Gene Summary

Gene:PIK3R2; phosphoinositide-3-kinase regulatory subunit 2
Aliases: p85, MPPH, P85B, MPPH1, p85-BETA
Summary:Phosphatidylinositol 3-kinase (PI3K) is a lipid kinase that phosphorylates phosphatidylinositol and similar compounds, creating second messengers important in growth signaling pathways. PI3K functions as a heterodimer of a regulatory and a catalytic subunit. The protein encoded by this gene is a regulatory component of PI3K. Three transcript variants, one protein coding and the other two non-protein coding, have been found for this gene. [provided by RefSeq, Apr 2019]
Databases:OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:phosphatidylinositol 3-kinase regulatory subunit beta
Source:NCBIAccessed: 30 August, 2019

Cancer Overview

Research Indicators

Publications Per Year (1994-2019)
Graph generated 30 August 2019 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

Tag cloud generated 30 August, 2019 using data from PubMed, MeSH and CancerIndex

Specific Cancers (5)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: PIK3R2 (cancer-related)

Ma Q, Lu Y, Gu Y
ENKUR Is Involved in the Regulation of Cellular Biology in Colorectal Cancer Cells via PI3K/Akt Signaling Pathway.
Technol Cancer Res Treat. 2019; 18:1533033819841433 [PubMed] Free Access to Full Article Related Publications
Colorectal cancer is one of the most prevalent malignancies worldwide. ENKUR is a transient receptor potential canonical-binding protein that acts as a potential regulator or effector of transient receptor potential canonical channels. It also directly interacts with the p85 regulatory subunit of phosphoinositide 3-kinase. However, the role of ENKUR in colorectal cancer remains unclear. In the present study, the expression profiles of ENKUR in the The Cancer Genome Atlas and ONCOMINE databases were analyzed. Significant downregulation of ENKUR was observed in clinical tumor samples of various cancer types, including colorectal cancer. Decreased ENKUR messenger RNA expression and ENKUR protein level were detected in 6 human colorectal cancer cell lines. Silencing of ENKUR in colorectal cancer cells led to enhanced cell proliferation, migration, and invasion, while the opposite effects were achieved in ENKUR-overexpressing cells. Furthermore, ENKUR-underexpressing cells exhibited increased activity of phosphoinositide 3-kinase /Akt signaling pathway. Downregulation of the epithelial marker, E-cadherin, and upregulation of the mesenchymal markers, vimentin and N-cadherin, were detected in ENKUR-underexpressing cells, suggesting the induction of epithelial-mesenchymal transition. In conclusion, the present study demonstrates that ENKUR may be responsible for alterations in the proliferative, migratory, and invasive potential of colorectal cancer cells through possible involvement in the phosphoinositide 3-kinase /Akt signaling pathway.

Yang X, Huang WT, Wu HY, et al.
Novel drug candidate for the treatment of several soft‑tissue sarcoma histologic subtypes: A computational method using survival‑associated gene signatures for drug repurposing.
Oncol Rep. 2019; 41(4):2241-2253 [PubMed] Free Access to Full Article Related Publications
Systemic treatment options for soft tissue sarcomas (STSs) have remained unchanged despite the need for novel drug candidates to improve STS outcomes. Drug repurposing involves the application of clinical drugs to different diseases, reducing development time, and cost. It has also become a fast and effective way to identify drug candidates. The present study used a computational method to screen three drug‑gene interaction databases for novel drug candidates for the treatment of several common STS histologic subtypes through drug repurposing. STS survival‑associated genes were generated by conducting a univariate cox regression analysis using The Cancer Genome Atlas survival data. These genes were then applied to three databases (the Connectivity Map, the Drug Gene Interaction Database and the L1000 Fireworks Display) to identify drug candidates for STS treatment. Additionally, pathway analysis and molecular docking were conducted to evaluate the molecular mechanisms of the candidate drug. Bepridil was identified as a potential candidate for several STS histologic subtype treatments by overlapping the screening results from three drug‑gene interaction databases. The pathway analysis with the Kyoto Encyclopedia of Genes and Genomes predicted that Bepridil may target CRK, fibroblast growth factor receptor 4 (FGFR4), laminin subunit β1 (LAMB1), phosphoinositide‑3‑kinase regulatory subunit 2 (PIK3R2), WNT5A, cluster of differentiation 47 (CD47), elastase, neutrophil expressed (ELANE), 15‑hydroxyprostaglandin dehydrogenase (HPGD) and protein kinase cβ (PRKCB) to suppress STS development. Further molecular docking simulation suggested a relatively stable binding selectivity between Bepridil and eight proteins (CRK, FGFR4, LAMB1, PIK3R2, CD47, ELANE, HPGD, and PRKCB). In conclusion, a computational method was used to identify Bepridil as a potential candidate for the treatment of several common STS histologic subtypes. Experimental validation of these in silico results is necessary before clinical translation can occur.

Zheng X, Liu M, Song Y, Feng C
Long Noncoding RNA-ATB Impairs the Function of Tumor Suppressor miR-126-Mediated Signals in Endometrial Cancer for Tumor Growth and Metastasis.
Cancer Biother Radiopharm. 2019; 34(1):47-55 [PubMed] Related Publications
OBJECTIVE: Long non-coding RNA-ATB (Lnc-ATB) have been reported to promote tumor proliferation and metastasis via regulation of tumor suppressive miRNA-related signals. Patients with endometrial cancer (EC) have advanced stage disease or metastasis have poor prognosis. We here investigated the role of Lnc-ATB in endometrial cancer.
METHODS: Endometrial cancer tissues and normal tissues (n = 35) were collected to determine the expression and clinical significance of Lnc-ATB, and bioinformatics analysis was used to predict the miRNA target. siRNA was used to estimate the function of Lnc-ATB in EC cell lines and in vivo.
RESULT: The expression of Lnc-ATB is up-regulated in tumor tissues and EC cell lines. Patients with high expressed Lnc-ATB have high FIGO stage and poor tumor differentiation. The tumor suppressor miR-126 interacted with Lnc-ATB. Down-regulated miR-126 negative correlated with FIGO stage and tumor differentiation. Knockdown of Lnc-ATB in RL95 and HEC1A cell lines increased the miR-126 level and impaired the cell vitality, induced caspase-3-related tumor apoptosis and G1/S arrest. However, abrogation of miR-126 by its inhibitors counteracted Lnc-ATB knockdown-induced tumor inhibition via regulation of miR-126 target gene PIK3R2 and Sox2-related apoptosis and cell cycle pathway. Meanwhile, Lnc-ATB knockdown also suppressed the migration and invasion and inhibited TGF-β-induced epithelial-mesenchymal transition (EMT) phenotype via miR-126. Knockdown of Lnc-ATB in vivo remarkably induced tumor regression via restoration of tumor suppressor miR-126, leading to deceased tumor volume, reduced expression of PCNA and PIK3R2/Sox2 signals and EMT phenotype in tumor tissues.
CONCLUSION: These data demonstrate the tumorigenic role of Lnc-ATBs in endometrial cancer via abrogation of tumor suppressor miR-126 signals.

Katase N, Nishimatsu SI, Yamauchi A, et al.
DKK3 knockdown confers negative effects on the malignant potency of head and neck squamous cell carcinoma cells via the PI3K/Akt and MAPK signaling pathways.
Int J Oncol. 2019; 54(3):1021-1032 [PubMed] Related Publications
Dickkopf‑related protein 3 (DKK3), which is a member of the Dickkopf WNT signaling pathway inhibitor family, is considered to be a tumor suppressor, due to its reduced expression in cancer cells and its ability to induce apoptosis when overexpressed by adenovirus. However, our previous study demonstrated alternative functions for DKK3 in head and neck squamous cell carcinoma (HNSCC). Our study reported that DKK3 expression was predominantly upregulated in HNSCC cell lines and tissue samples, and its expression was significantly correlated with poor prognosis. Furthermore, DKK3 overexpression in HNSCC cells significantly increased cancer cell proliferation, migration, invasion and in vivo tumor growth. These data have led to the hypothesis that DKK3 may exert oncogenic functions and may increase the malignant properties of HNSCC. The present study established a stable DKK3 knockdown cell line (HSC‑3 shDKK3) using lentivirus‑mediated short hairpin RNA, and assessed its effects on cancer cell behavior using MTT, migration and invasion assays. In addition, its effects on in vivo tumor growth were assessed using a xenograft model. Furthermore, the molecular mechanisms underlying the effects of DKK3 knockdown were investigated by microarray analysis, pathway analysis and western blotting. Compared with control cells, HSC‑3 shDKK3 cells exhibited significantly reduced proliferation, migration and invasion, and formed significantly smaller tumor masses when subcutaneously transplanted into nude mice. In addition, in HSC‑3 shDKK3 cells, the expression levels of phosphorylated (p)‑protein kinase B (Akt) (Ser473), p‑phosphoinositide 3‑kinase (PI3K) p85 (Tyr467), p‑PI3K p55 (Try199), p‑3‑phosphoinositide‑dependent protein kinase‑1 (PDK1) (Ser241) and total p38 mitogen‑activated protein kinase (MAPK) were reduced. Furthermore, phosphorylation of mechanistic target of rapamycin (mTOR) (Ser2448) was slightly decreased in HSC‑3 shDKK3 cells, which may be due to the increased expression of DEP domain‑containing mTOR‑interacting protein. Conversely, DKK3 overexpression in HSC‑3 shDKK3 cells rescued cellular proliferation, migration and invasion. With regards to expression levels, p‑PI3K and p‑PDK1 expression was not altered, whereas mTOR and p‑p38 MAPK expression was elevated. These data supported the hypothesis and indicated that DKK3 may contribute to the malignant phenotype of HNSCC cells via the PI3K/Akt/mTOR and MAPK signaling pathways.

Li X, Han F, Liu W, Shi X
PTBP1 promotes tumorigenesis by regulating apoptosis and cell cycle in colon cancer.
Bull Cancer. 2018; 105(12):1193-1201 [PubMed] Related Publications
Increased expression of polypyrimidine tract-binding protein 1 (PTBP1) has been observed in human ovarian tumors, glioblastomas, and breast cancer, but its biological roles in tumorigenesis is not fully clear. In the present research, we investigated the biological role of PTBP1 in colon cancer. We found that PTBP1 was overexpressed both in colon cancer cell lines and tissues. Tissue microarray analysis (TMA) indicated that low PTBP1 expression predicted a favorable overall survival for colon cancer patients. Using small interfering RNA technology, we found that down-regulation of PTBP1 significantly inhibited colon cancer cell growth/proliferation, and induced cell cycle arrest as well as apoptosis in vitro. Western blot analysis showed that siRNA PTBP1 could up-regulate the expression of cytoC, p53 and Bax as well as down-regulated p85, p-AKT, cyclinD1, CDK4 and Bcl2 compared to the control. Furthermore, Caspase-3 and PARP1 were activated when PTBP1 is knockdown. This study implies that PTBP1 plays an important role in tumorigenesis of colon cancer.

Li D, Pan Y, Huang Y, et al.
PAK5 Induces EMT and Promotes Cell Migration and Invasion by Activating the PI3K/AKT Pathway in Ovarian Cancer.
Anal Cell Pathol (Amst). 2018; 2018:8073124 [PubMed] Free Access to Full Article Related Publications
Ovarian cancer is the most lethal gynecologic cancer and currently ranks fifth in causing cancer-related deaths among women. P21

Choi JR, Koh SB, Kim HR, et al.
Radon Exposure-induced Genetic Variations in Lung Cancers among Never Smokers.
J Korean Med Sci. 2018; 33(29):e207 [PubMed] Free Access to Full Article Related Publications
Background: Lung cancer in never smokers (LCINS) differs etiologically and clinically from lung cancer attributed to smoking. After smoking, radon exposure is the second leading cause and the primary risk factor of lung cancer among never smokers. Exposure to radon can lead to genetic and epigenetic alterations in tumor genomes affecting genes and pathways involved in lung cancer development. The present study sought to explore genetic alterations associated with LCINS exposed to radon gas indoors.
Methods: Genetic associations were assessed via a case-control study of LCINS (39 cases and 30 controls) using next generation sequencing. Associations between genetic mutations and high exposure to radon were investigated by OncoPrint and heatmap graphs. Bioinformatic analysis was conducted using various tools. According radon exposure levels, we divided subjects in two groups of cases and controls.
Results: We found that ABL2 rs117218074, SMARCA4 rs2288845, PIK3R2 rs142933317, MAPK1 rs1803545, and androgen receptor (AR) rs66766400 were associated with LCINS exposed to high radon levels. Among these, Chromodomain helicase DNA-binding protein 4 (CHD4) rs74790047, TSC2 rs2121870, and AR rs66766408 were identified as common exonic mutations in both lung cancer patients and normal individuals exposed to high levels of radon indoor.
Conclusion: We identified that CHD4 rs74790047, TSC2 rs2121870, and AR rs66766408 are found to be common exonic mutations in both lung cancer patients and normal individuals exposed to radon indoors. Further analysis is needed to determine whether these genes are completely responsible for LCINS exposed to residential radon.

Dornan GL, Burke JE
Molecular Mechanisms of Human Disease Mediated by Oncogenic and Primary Immunodeficiency Mutations in Class IA Phosphoinositide 3-Kinases.
Front Immunol. 2018; 9:575 [PubMed] Free Access to Full Article Related Publications
The signaling lipid phosphatidylinositol 3,4,5, trisphosphate (PIP

Xie JJ, Jiang YY, Jiang Y, et al.
Super-Enhancer-Driven Long Non-Coding RNA LINC01503, Regulated by TP63, Is Over-Expressed and Oncogenic in Squamous Cell Carcinoma.
Gastroenterology. 2018; 154(8):2137-2151.e1 [PubMed] Related Publications
BACKGROUND & AIMS: Long non-coding RNAs (lncRNAs) are expressed in tissue-specific pattern, but it is not clear how these are regulated. We aimed to identify squamous cell carcinoma (SCC)-specific lncRNAs and investigate mechanisms that control their expression and function.
METHODS: We studied expression patterns and functions of 4 SCC-specific lncRNAs. We obtained 113 esophageal SCC (ESCC) and matched non-tumor esophageal tissues from a hospital in Shantou City, China, and performed quantitative reverse transcription polymerase chain reaction assays to measure expression levels of LINC01503. We collected clinical data from patients and compared expression levels with survival times. LINC01503 was knocked down using small interfering RNAs and oligonucleotides in TE7, TE5, and KYSE510 cell lines and overexpressed in KYSE30 cells. Cells were analyzed by chromatin immunoprecipitation sequencing, luciferase reporter assays, colony formation, migration and invasion, and mass spectrometry analyses. Cells were injected into nude mice and growth of xenograft tumors was measured. LINC01503 interaction with proteins was studied using fluorescence in situ hybridization, RNA pulldown, and RNA immunoprecipitation analyses.
RESULTS: We identified a lncRNA, LINC01503, which is regulated by a super enhancer and is expressed at significantly higher levels in esophageal and head and neck SCCs than in non-tumor tissues. High levels in SCCs correlated with shorter survival times of patients. The transcription factor TP63 bound to the super enhancer at the LINC01503 locus and activated its transcription. Expression of LINC01503 in ESCC cell lines increased their proliferation, colony formation, migration, and invasion. Knockdown of LINC01503 in SCC cells reduced their proliferation, colony formation, migration, and invasion, and the growth of xenograft tumors in nude mice. Expression of LINC01503 in ESCC cell lines reduced ERK2 dephosphorylation by DUSP6, leading to activation of ERK signaling via MAPK. LINC01503 disrupted the interaction between EBP1 and the p85 subunit of PI3K, increasing AKT signaling.
CONCLUSIONS: We identified an lncRNA, LINC01503, which is increased in SCC cells compared with non-tumor cells. Increased expression of LINC01503 promotes ESCC cell proliferation, migration, invasion, and growth of xenograft tumors. It might be developed as a biomarker of aggressive SCCs in patients.

Xu S, Li Y, Lu Y, et al.
LZTS2 inhibits PI3K/AKT activation and radioresistance in nasopharyngeal carcinoma by interacting with p85.
Cancer Lett. 2018; 420:38-48 [PubMed] Related Publications
Phosphoinositide 3-kinase (PI3K) activity is aberrantly activated in nasopharyngeal carcinoma. However, the underlying mechanisms remain unclear. Here, we found that Leucine zipper tumor suppressor 2 (LZTS2) was downregulated and predicted poor prognosis in nasopharyngeal carcinoma patients. Furthermore, we identified the PI3K subunit p85 as a novel LZTS2-interacting protein using an unbiased proteomics approach. Moreover, we demonstrated that LZTS2 competes with p110 for p85 binding and inhibits activation of the PI3K/AKT signaling pathway. Functionally, we showed that LZTS2 suppresses tumorigenesis and radioresistance in nasopharyngeal carcinoma in a p85-dependent manner. Taken together, our results not only provide understanding of the molecular mechanisms by which PI3K/AKT signaling is activated but also suggest that targeting the LZTS2/PI3K/AKT signaling axis is a promising therapeutic strategy for radiosensitization of nasopharyngeal carcinoma.

Qi L, Sun K, Zhuang Y, et al.
Study on the association between PI3K/AKT/mTOR signaling pathway gene polymorphism and susceptibility to gastric cancer.
J BUON. 2017 Nov-Dec; 22(6):1488-1493 [PubMed] Related Publications
PURPOSE: Excessive activation of PI3K/AKT/mTOR signaling pathway is one of the most common changes in human cancers, and single nucleotide polymorphisms (SNPs) existing in its functional region can affect the occurrence process of a variety of cancers. This study aimed to screen out the SNPs associated with susceptibility to gastric cancer in the PI3K/AKT/mT0R signaling pathway.
METHODS: In this case-control study, the tagging SNPs in the promoter region5'-UTR, exon region or 3'-UTR of PIK3CA, PIK3CB, PIK3R1, PIK3R2, PIK3R3, AKT1, AKT2, AKT3 and mTOR genes were screened out. The relationship between the genetic variation of PI3K/AKT/mT0R signaling pathway genes and the susceptibility to gastric cancer in Chinese Han population was investigated by this casecontrol study.
RESULTS: The results showed that the polymorphisms of the two loci, PIK3R3 rs7536272 (Additive model: OR=1.16, 95% CI=1.01-1.35) and mTOR rs2295080 (GG vs TT: OR=0.75, 95% CI=0.60-0.94; Additive model: OR=0.78, 95% CI=0.66- 0.93), were associated with the risk of gastric cancer in the studied population and there was a combined effect between the two loci (ptrend=0.005).
CONCLUSIONS: In conclusion, the polymorphisms of the two loci, PIK3R3 rs7536272 and mTOR rs2295080, on the PI3K/AKT/mTOR signaling pathway genes are associated with genetic susceptibility to gastric cancer in Chinese population.

Wu D, Lu P, Mi X, Miao J
Downregulation of miR-503 contributes to the development of drug resistance in ovarian cancer by targeting PI3K p85.
Arch Gynecol Obstet. 2018; 297(3):699-707 [PubMed] Related Publications
OBJECTIVE: Cisplatin is an important chemotherapeutic agent frequently used in the treatment of ovarian cancer. However, resistance to cisplatin is an obstacle to the treatment of ovarian cancer. Recently, many studies have demonstrated that microRNAs (miRNAs) are involved in the drug resistance of ovarian cancer cells. In this study, we explored the role of miR-503 in cisplatin-resistant ovarian cancer.
MATERIALS AND METHODS: To investigate the relationship between miR-503 expression and the sensitivity of ovarian cancer cells to cisplatin, the cells were transfected with miR-503 mimics/inhibitors. The relative expression of miR-503 RNA and its targeted gene PI3K mRNA were detected by real-time PCR (RT-PCR). Western blot was used to measure relevant protein levels. Flow cytometry and CCK-8 assay were used to analyze cell proliferation and apoptosis.
RESULTS: MiR-503 expression was significantly downregulated in cisplatin-resistant ovarian cancer cell line SKOV3/DDP compared with parental SKOV3. Over-expression and knock-down of miR-503 partially regulated apoptotic activity and changed the cisplatin resistance of ovarian cancer cells. In exploring the underlying mechanisms of miR-503 in ovarian cancer cells' resistance to cisplatin, we found that miR-503 can directly target PI3K p85 and participates in the regulation of the PI3K/Akt signaling pathway. In vivo, miR-503 agomirs combined with cisplatin treatment significantly reduced the growth of tumors compared with cisplatin alone.
CONCLUSIONS: Our data suggest that miR-503 might be a sensitizer to cisplatin treatment in ovarian cancer by targeting PI3K p85, thus giving a new insight into developing therapeutic strategies to overcome cisplatin resistance in ovarian cancer.

He S, Zhang J, Zhang W, et al.
FOXA1 inhibits hepatocellular carcinoma progression by suppressing PIK3R1 expression in male patients.
J Exp Clin Cancer Res. 2017; 36(1):175 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Forkhead box A1 (FOXA1) expression is associated with various types of tumors; however, the function and underlying mechanism of FOXA1 in the development of hepatocellular carcinoma (HCC) remains obscure.
METHODS: Here, we investigated the role of FOXA1 in the development of HCC by applying gene function gain and loss analysis to HepG2 and Hep3B cell lines, and comparing outcomes with those of clinical HCC samples.
RESULTS: Phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1), which encodes protein PI3Kp85 (p85), was identified as a FOXA1 target gene. Analyses of the mechanism and function revealed that FOXA1 suppresses hepatocellular carcinoma cell viability and motility by inhibiting PI3K/Akt signaling through direct inhibition of PIK3R1 transcription. Moreover, in clinical samples from male HCC patients, FOXA1 expression was much lower, whereas PI3Kp85 levels were much higher in tumor than in non-tumor tissues. Elevated PI3Kp85 is an unfavorable factor in HCC.
CONCLUSIONS: As a tumor suppressor, FOXA1 targets PIK3R1 directly to inhibit PI3K/Akt signaling pathway, thus exerting a negative regulatory effect on proliferation, migration, and invasion of HCC in male patients.

Guo W, You X, Wang X, et al.
A synthetic peptide hijacks the catalytic subunit of class I PI3K to suppress the growth of cancer cells.
Cancer Lett. 2017; 405:1-9 [PubMed] Related Publications
Activation of class I Phosphoinositide 3-kinases (PI3Ks) by mutation or overexpression closely correlates with the development of various human cancers. Class I PI3Ks are heterodimers composed of p110 catalytic subunits and regulatory subunits represented by p85. PAQR3 has been found to inhibit p110α activity by blocking its interaction with p85. In this study, we identified the N-terminal 6-55 amino acid residues of PAQR3 being sufficient for its interaction with p110α. A synthetic peptide, P6-55, that contains the N-terminus of PAQR3 could disrupt the interactions of p110α with both PAQR3 and p85. The activity of PI3K was also inhibited by P6-55, accompanied by significant inhibition of cancer cell proliferation. In a xenograft mouse model, P6-55 was able to reduce tumor growth in vivo. Furthermore, P6-55 was capable of inhibiting the elevated basal PI3K activity of H1047R, a hotspot mutation found in many types of human cancers. The cell proliferation and migration of cancer cells bearing H1047R mutation were also reduced by P6-55. In conclusion, our study provides a proof of concept that blocking the interaction of p110α with p85 by a peptide can serve as a new strategy to inhibit the oncogenic activity of PI3K in cancer therapy.

Thorpe LM, Spangle JM, Ohlson CE, et al.
PI3K-p110α mediates the oncogenic activity induced by loss of the novel tumor suppressor PI3K-p85α.
Proc Natl Acad Sci U S A. 2017; 114(27):7095-7100 [PubMed] Free Access to Full Article Related Publications
Mutation or loss of the p85 regulatory subunit of phosphatidylinositol 3-kinase (PI3K) is emerging as a transforming factor in cancer, but the mechanism of transformation has been controversial. Here we find that hemizygous deletion of the

Demirci S, Doğan A, Başak Türkmen N, et al.
Poloxamer P85 increases anticancer activity of Schiff base against prostate cancer in vitro and in vivo.
Anticancer Drugs. 2017; 28(8):869-879 [PubMed] Related Publications
Prostate cancer is the second most common cancer among men and the leading cause of death after lung cancer. Development of hormone-refractory disease is a crucial step for prostate cancer progression for which an effective treatment option is currently unavailable. Therefore, there is a need for new agents that can efficiently target cancer cells, decrease tumor growth, and thereby extend the survival of patients in late-stage castration-resistant prostate cancer. In the current study, a novel heterodinuclear copper(II)Mn(II) Schiff base complex combined with P85 was used to evaluate anticancer activity against prostate cancer in vitro and in vivo. Cell proliferation and cytotoxicity were evaluated by cell viability, gene, and protein expression assays in vitro. Results showed that the heterodinuclear copper(II)Mn(II) complex-P85 combination decreased cell proliferation by upregulating the apoptotic gene expressions and blocking the cell proliferation-related pathways. Tramp-C1-injected C57/B16 mice were used to mimic a prostate cancer model. Treatment combination of Schiff base complex and P85 significantly enhanced the cellular uptake of chemicals (by blocking the drug transporters and increased life time), suppressed tumor growth, and decreased tumor volume steadily over the course of the experiments. Overall, heterodinuclear copper(II)Mn(II) complex-P85 showed remarkable anticancer activity against prostate cancer in in vitro and in vivo.

Chang F, Liu L, Fang E, et al.
Molecular Diagnosis of Mosaic Overgrowth Syndromes Using a Custom-Designed Next-Generation Sequencing Panel.
J Mol Diagn. 2017; 19(4):613-624 [PubMed] Related Publications
Recent studies have discovered a group of overgrowth syndromes, such as congenital lipomatous overgrowth with vascular, epidermal, and skeletal anomalies (CLOVES) syndrome, Proteus syndrome, and megalencephaly-capillary malformation-polymicrogyria (MCAP) syndrome, are caused by somatic activating variants in genes involved in the phosphatidylinositol 3-kinase/AKT/mechanistic target of rapamycin pathway. Because of the low-abundance nature of these variants, Sanger sequencing often yields negative results. We have developed and validated a next-generation sequencing (NGS) panel that targets all known variants associated with these syndromes. Fifty cases, including two prenatal cases, were tested using the panel. A pathogenic variant in the PIK3CA, PIK3R2, or AKT1 gene was identified in 28 of the 50 cases with the variant allele frequencies ranging from 1.0% to 49.2%. These variants were only present in the affected tissues in most of the cases, demonstrating a causal role in the development of these diseases. In vitro cell culture showed significant enrichment of the cells harboring variant alleles, suggesting that these variants render growth advantages to mutant cells. Phenotype-genotype correlation analysis showed PIK3CA mutation hotspots at residues E542, E545, and H1047 are often associated with CLOVES syndrome, whereas PIK3CA G914R is preferentially related to MCAP. We thus demonstrate that NGS technology is highly sensitive for detecting low-level mosaicism and can facilitate clinical diagnosis of mosaic overgrowth syndromes in both prenatal and postnatal settings.

Jiang SH, Li J, Dong FY, et al.
Increased Serotonin Signaling Contributes to the Warburg Effect in Pancreatic Tumor Cells Under Metabolic Stress and Promotes Growth of Pancreatic Tumors in Mice.
Gastroenterology. 2017; 153(1):277-291.e19 [PubMed] Related Publications
BACKGROUND & AIMS: Desmoplasia and poor vascularity cause severe metabolic stress in pancreatic ductal adenocarcinomas (PDACs). Serotonin (5-HT) is a neuromodulator with neurotransmitter and neuroendocrine functions that contributes to tumorigenesis. We investigated the role of 5-HT signaling in the growth of pancreatic tumors.
METHODS: We measured the levels of proteins that regulate 5-HT synthesis, packaging, and degradation in pancreata from Kras
RESULTS: In immunohistochemical analysis of a tissue microarray of PDAC specimens, increased levels of TPH1 and decreased level of MAOA, which regulate 5-HT synthesis and degradation, correlated with stage and size of PDACs and shorter patient survival time. We found levels of 5-HT to be increased in human PDAC tissues compared with non-tumor pancreatic tissues, and PDAC cell lines compared with non-transformed pancreatic cells. Incubation of PDAC cell lines with 5-HT increased proliferation and prevented apoptosis. Agonists of HTR2B, but not other 5-HT receptors, promoted proliferation and prevented apoptosis of PDAC cells. Knockdown of HTR2B in PDAC cells, or incubation of cells with HTR2B inhibitors, reduced their growth as xenograft tumors in mice. We observed a correlation between 5-HT and glycolytic flux in PDAC cells; levels of metabolic enzymes involved in glycolysis, the phosphate pentose pathway, and hexosamine biosynthesis pathway increased significantly in PDAC cells following 5-HT stimulation. 5-HT stimulation led to formation of the HTR2B-LYN-p85 complex, which increased PI3K-Akt-mTOR signaling and the Warburg effect by increasing protein levels of MYC and HIF1A. Administration of SB204741 to KPC mice slowed growth and metabolism of established pancreatic tumors and prolonged survival of the mice.
CONCLUSIONS: Human PDACs have increased levels of 5-HT, and PDAC cells increase expression of its receptor, HTR2B. These increases allow for tumor glycolysis under metabolic stress and promote growth of pancreatic tumors and PDAC xenograft tumors in mice.

Guinn D, Lehman A, Fabian C, et al.
The regulation of tumor-suppressive microRNA, miR-126, in chronic lymphocytic leukemia.
Cancer Med. 2017; 6(4):778-787 [PubMed] Free Access to Full Article Related Publications
The introduction of miR profiling of chronic lymphocytic leukemia (CLL) patients with different cytogenetic profiles and responses to therapy has allowed incorporation of important miR-mRNA interactions into the understanding of disease biology. In this study, we performed miR expression analysis using NanoString nCounter to discover differentially regulated miRs after therapy with the Bruton tyrosine kinase inhibitor ibrutinib. Of the differentially regulated miRs in the discovery set, miR-29c and miR-126 were confirmed using real-time PCR to be upregulated in CLL patient cells with ibrutinib therapy. In the validation set, an inverse correlation was observed between miR-126 levels and expression of its putative target p85β, an isoform of the phosphoinositide 3-kinase p85 regulatory subunit. We found that mRNA for the host gene EGFL7, primary unprocessed miR-126, and mature miR-126 are all downregulated in CLL cells compared to normal B cells. Patients in later stages of disease have a greater decrease in miR-126 expression compared to treatment-naive patients, indicating that lower miR-126 levels may associate with disease progression. Overexpression of miR-126 in leukemia cell lines significantly downregulates p85β expression and decreases activation of prosurvival mitogen-activated protein kinase (MAPK) signaling. These results implicate miR-126 in the pathology of CLL.

Madi A, Fisher D, Maughan TS, et al.
Comprehensive pharmacogenetic profiling of the epidermal growth factor receptor pathway for biomarkers of response to, and toxicity from, cetuximab.
J Med Genet. 2017; 54(8):567-571 [PubMed] Related Publications
BACKGROUND: Somatic mutations in the epidermal growth factor receptor (EGFR) intracellular signalling pathways predict non-response to cetuximab in the treatment of advanced colorectal cancer (aCRC). We hypothesised that common germline variants within these pathways may also play similar roles.
METHODS: We analysed 54 potentially functional, common, inherited EGFR pathway variants in 815 patients with aCRC treated with oxaliplatin-fluoropyrimidine chemotherapy plus cetuximab. Primary endpoints were response and skin rash (SR). We had >85% power to detect ORs=1.6 for variants with minor allele frequencies >20%.
RESULTS: We identified five potential biomarkers for response and four for SR, although none remained significant after correction for multiple testing. Our initial data supported a role for Ser313Pro in
CONCLUSIONS: Our study highlights the need to validate potential pharmacogenetic biomarkers. We did not find strong evidence for common germline biomarkers of cetuximab response and toxicity.

Teng Y, Ngoka L, Cowell JK
Promotion of invasion by mutant RAS is dependent on activation of the WASF3 metastasis promoter gene.
Genes Chromosomes Cancer. 2017; 56(6):493-500 [PubMed] Free Access to Full Article Related Publications
Metastasis represents an end stage in the evolution of cancer progression and has been related to specific genetic pathways. Overexpression of mutant RAS in particular appears to promote invasion and metastasis, although exactly how this occurs has not been well characterized. It was previously showed that activation of the WASF3 protein regulates actin cytoskeleton dynamics that promote invasion. In this report, how WASF3 overexpression interacts with mutant RAS to increase invasion and metastasis was investigated. The ability of RAS to promote invasion and metastasis was shown to be dependent on WASF3 activation in a PI3K and AKT dependent manner. Proteomics analysis demonstrates the presence of AKT in the WASF3 immunocomplex which is enhanced by overexpression of mutant RAS. During these processes activation of ERK1/2 is not affected by loss of WASF3 expression. Analysis of the relative involvement of p85 and p110 in the WASF3 complex demonstrates that mutant RAS promotes dissociation of p85 promoting activation of p110. These studies provide a deeper understanding of the critical role for WASF3 in facilitating increased invasion potential in cancer cells expressing mutant RAS and supports the idea that targeting WASF3 in metastatic cells overexpressing RAS may be used to suppress invasion and metastasis.

King H, Thillai K, Whale A, et al.
PAK4 interacts with p85 alpha: implications for pancreatic cancer cell migration.
Sci Rep. 2017; 7:42575 [PubMed] Free Access to Full Article Related Publications
It has been reported that p21-activated kinase 4 (PAK4) is amplified in pancreatic cancer tissue. PAK4 is a member of the PAK family of serine/threonine kinases, which act as effectors for several small GTPases, and has been specifically identified to function downstream of HGF-mediated c-Met activation in a PI3K dependent manner. However, the functionality of PAK4 in pancreatic cancer and the contribution made by HGF signalling to pancreatic cancer cell motility remain to be elucidated. We now find that elevated PAK4 expression is coincident with increased expression levels of c-Met and the p85α subunit of PI3K. Furthermore, we demonstrate that pancreatic cancer cells have a specific motility response to HGF both in 2D and 3D physiomimetic organotypic assays; which can be suppressed by inhibition of PI3K. Significantly, we report a specific interaction between PAK4 and p85α and find that PAK4 deficient cells exhibit a reduction in Akt phosphorylation downstream of HGF signalling. These results implicate a novel role for PAK4 within the PI3K pathway via interaction with p85α. Thus, PAK4 could be an essential player in PDAC progression representing an interesting therapeutic opportunity.

Zhong ZF, Tan W, Tian K, et al.
Combined effects of furanodiene and doxorubicin on the migration and invasion of MDA-MB-231 breast cancer cells in vitro.
Oncol Rep. 2017; 37(4):2016-2024 [PubMed] Related Publications
Furanodiene is one of the major bioactive components isolated from the natural product of the plant, Curcuma wenyujin Y.H. Chen et C. Ling. Furanodiene has been found to exert anticancer effects in various types of cancer cell lines, as well as exhibit antimetastatic activities. However, the antimetastatic capacity of furanodiene in combination with the common chemotherapy drug doxorubicin has not been investigated. We found that doxorubicin at a non-toxic concentration induced cell migration and cell invasion in highly metastatic breast cancer cells. Combinational treatments with furanodiene and doxorubicin blocked the invasion and migration of MDA-MB-231 breast cancer cells in vitro. We also clarified the effects of the combination on the signaling pathways involved in migration, invasion, and cytoskeletal organization. When combined with doxorubicin, furanodiene downregulated the expression of integrin αV and β-catenin and inhibited the phosphorylation of paxillin, Src, focal adhesion kinase (FAK), p85, and Akt. Moreover, combinational treatments also resulted in a decrease in matrix metalloproteinase-9 (MMP-9). Further study demonstrated that the co-treatments with furanodiene did not significantly alter the effects of doxorubicin on the tubulin cytoskeleton, represented by no influence on the expression levels of RhoA, Cdc42, N-WASP, and α/β tubulin. These observations indicate that furanodiene is a potential agent that may be utilized to improve the anticancer efficacy of doxorubicin and overcome the risk of chemotherapy in highly metastatic breast cancer.

Koirala P, Huang J, Ho TT, et al.
LncRNA AK023948 is a positive regulator of AKT.
Nat Commun. 2017; 8:14422 [PubMed] Free Access to Full Article Related Publications
Despite the overwhelming number of human long non-coding RNAs (lncRNAs) reported so far, little is known about their physiological functions for the majority of them. The present study uses a CRISPR/Cas9-based synergistic activation mediator (SAM) system to identify potential lncRNAs capable of regulating AKT activity. Among lncRNAs identified from this screen, we demonstrate that AK023948 is a positive regulator for AKT. Knockout of AK023948 suppresses, whereas rescue with AK023948 restores the AKT activity. Mechanistically, AK023948 functionally interacts with DHX9 and p85. Importantly, AK023948 is required for the interaction between DHX9 and p85 to hence the p85 stability and promote AKT activity. Finally, AK023948 is upregulated in breast cancer; interrogation of TCGA data set indicates that upregulation of DHX9 in breast cancer is associated with poor survival. Together, this study demonstrates two previously uncharacterized factors AK023948 and DHX9 as important players in the AKT pathway, and that their upregulation may contribute to breast tumour progression.

Borzi C, Calzolari L, Centonze G, et al.
mir-660-p53-mir-486 Network: A New Key Regulatory Pathway in Lung Tumorigenesis.
Int J Mol Sci. 2017; 18(1) [PubMed] Free Access to Full Article Related Publications
Lung cancer is the most frequent cause of cancer-related death worldwide, with limited therapeutic options and rapid development of drug resistance. MicroRNAs, a class of small non-coding RNAs that control different physiological processes, have been associated with cancer development, as either oncomiRNAs or tumor-suppressor miRNAs. In the present study we investigated the interaction between mir-486-5p and mir-660-5p, two independent tumor-suppressor miRNAs, to assess their possible role and synergistic effect in lung cancer treatment. Our data show that mir-660-5p over-expression in A549 lung cancer cells induced a remarkable increase in mir-486-5p expression level and activity, detected as a reduction of its target gene, p85. mir-486-5p expression was confirmed by microRNA in situ hybridization. mir-660-5p modulated mir-486-5p through the silencing of Mouse Double Minute 2 (MDM2), one of its direct target, and then through p53 stimulation. This regulatory pathway was effective in A549, but not in H1299; therefore, only in the context of a functional p53 protein. Our findings support the conclusion that mir-486-5p is positively regulated by mir-660-5p in lung cancer cell lines, through the mir-660-MDM2-p53 pathway, making mir-660-5p even more interesting for its potential successful use in lung cancer therapy.

Yu W, Honisch S, Schmidt S, et al.
Chorein Sensitive Orai1 Expression and Store Operated Ca2+ Entry in Rhabdomyosarcoma Cells.
Cell Physiol Biochem. 2016; 40(5):1141-1152 [PubMed] Related Publications
BACKGROUND: Chorein, a protein encoded by VPS13A (vacuolar protein sorting-associated protein 13A), is defective in chorea acanthocytosis, a rare disease characterized by acanthocytosis of red blood cells and neuronal cell death with progressive hyperkinetic movement disorder, cognitive dysfunction, behavioral abnormalities and chronic hyperkalemia. Chorein is highly expressed in ZF rhabdomyosarcoma cells and counteracts apoptosis of those cells. Chorein is effective in part by interacting with and fostering stimulation of phosphoinositide-3-kinase (PI3K)-p85-subunit. PI3K dependent signaling includes the serum and glucocorticoid inducible kinase SGK1. The kinase activates NFκB with subsequent up-regulation of the Ca2+ channel subunit Orai1, which accomplishes store operated Ca2+ entry (SOCE). Orai1 and SOCE have been shown to confer survival of tumor cells. The present study thus explored whether chorein impacts on Orai1 expression and SOCE.
METHODS: In rhabdomyosarcoma cells chorein, Orai1, NFκB and SGK1 transcript levels were quantified by RT-PCR, Orai1 protein abundance by Western blotting, FACS analysis and confocal laser microscopy, [Ca2+]i utilizing Fura-2 fluorescence, and SOCE from the increase of [Ca2+]i following store depletion with extracellular Ca2+ removal and inhibition of the sarcoendoplasmatic reticular Ca2+ ATPase with thapsigargin.
RESULTS: The mRNA coding for chorein was most abundant in drug resistant, poorly differentiated human ZF rhabdomyosarcoma cells. Chorein silencing significantly decreased Orai1 transcript levels and Orai1 protein expression, as well as SGK1 and NFκB transcript levels. SOCE in ZF rhabdomyosarcoma cells was significantly blunted by chorein silencing, Orai1 inhibitor 2-APB (50 µM), SGK1 inhibitor EMD638683 (50 µM, 10 h) and NFκB inhibitor wogonin (50 µM, 24 h).
CONCLUSION: Chorein is a stimulator of Orai1 expression and thus of store operated Ca2+ entry. The effect may involve SGK1 and NFκB.

Vallejo-Díaz J, Olazabal-Morán M, Cariaga-Martínez AE, et al.
Targeted depletion of PIK3R2 induces regression of lung squamous cell carcinoma.
Oncotarget. 2016; 7(51):85063-85078 [PubMed] Free Access to Full Article Related Publications
Oncogenic mutations in the PI3K/AKT pathway are present in nearly half of human tumors. Nonetheless, inhibitory compounds of the pathway often induce pathway rebound and tumor resistance. We find that lung squamous cell carcinoma (SQCC), which accounts for ~20% of lung cancer, exhibits increased expression of the PI3K subunit PIK3R2, which is at low expression levels in normal tissues. We tested a new approach to interfere with PI3K/AKT pathway activation in lung SQCC. We generated tumor xenografts of SQCC cell lines and examined the consequences of targeting PIK3R2 expression. In tumors with high PIK3R2 expression, and independently of PIK3CA, KRAS, or PTEN mutations, PIK3R2 depletion induced lung SQCC xenograft regression without triggering PI3K/AKT pathway rebound. These results validate the use PIK3R2 interfering tools for the treatment of lung squamous cell carcinoma.

Saleh AJ, Soltani BM, Dokanehiifard S, et al.
Experimental verification of a predicted novel microRNA located in human PIK3CA gene with a potential oncogenic function in colorectal cancer.
Tumour Biol. 2016; 37(10):14089-14101 [PubMed] Related Publications
PI3K/AKT signaling is involved in cell survival, proliferation, and migration. In this pathway, PI3Kα enzyme is composed of a regulatory protein encoded by p85 gene and a catalytic protein encoded by PIK3CA gene. Human PIK3CA locus is amplified in several cancers including lung and colorectal cancer (CRC). Therefore, microRNAs (miRNAs) that are encoded within the PIK3CA gene might have a role in cancer development. Here, we report a novel microRNA named PIK3CA-miR1 (EBI accession no. LN626315), which is located within PIK3CA gene. A DNA segment corresponding to PIK3CA-premir1 sequence was transfected in human cell lines that resulted in generation of mature exogenous PIK3CA-miR1. Following the overexpression of PIK3CA-miR1, its predicted target genes (APPL1 and TrkC) were significantly downregulated in the CRC-originated HCT116 and SW480 cell lines, detected by qRT-PCR. Then, dual luciferase assay supported the interaction of PIK3CA-miR1 with APPL1 and TrkC transcripts. Endogenous PIK3CA-miR1 expression was also detected in several cell lines (highly in HCT116 and SW480) and highly in CRC specimens. Consistently, overexpression of PIK3CA-premir1 in HCT116 and SW480 cells resulted in significant reduction of the sub-G1 cell distribution and apoptotic cell rate, as detected by flowcytometry, and resulted in increased cell proliferation, as detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. PIK3CA-miR1 overexpression also resulted in Wnt signaling upregulation detected by Top/Fop assay. Overall, accumulative evidences indicated the presence of a bona fide novel onco-miRNA encoded within the PIK3CA oncogene, which is highly expressed in colorectal cancer and has a survival effect in CRC-originated cells.

Amaral CL, Freitas LB, Tamura RE, et al.
S6Ks isoforms contribute to viability, migration, docetaxel resistance and tumor formation of prostate cancer cells.
BMC Cancer. 2016; 16:602 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: The S6 Kinase (S6K) proteins are some of the main downstream effectors of the mammalian Target Of Rapamycin (mTOR) and act as key regulators of protein synthesis and cell growth. S6K is overexpressed in a variety of human tumors and is correlated to poor prognosis in prostate cancer. Due to the current urgency to identify factors involved in prostate cancer progression, we aimed to reveal the cellular functions of three S6K isoforms-p70-S6K1, p85-S6K1 and p54-S6K2-in prostate cancer, as well as their potential as therapeutic targets.
METHODS: In this study we performed S6K knockdown and overexpression and investigated its role in prostate cancer cell proliferation, colony formation, viability, migration and resistance to docetaxel treatment. In addition, we measured tumor growth in Nude mice injected with PC3 cells overexpressing S6K isoforms and tested the efficacy of a new available S6K1 inhibitor in vitro.
RESULTS: S6Ks overexpression enhanced PC3-luc cell line viability, migration, resistance to docetaxel and tumor formation in Nude mice. Only S6K2 knockdown rendered prostate cancer cells more sensitive to docetaxel. S6K1 inhibitor PF-4708671 was particularly effective for reducing migration and proliferation of PC3 cell line.
CONCLUSIONS: These findings demonstrate that S6Ks play an important role in prostate cancer progression, enhancing cell viability, migration and chemotherapy resistance, and place both S6K1 and S6K2 as a potential targets in advanced prostate cancer. We also provide evidence that S6K1 inhibitor PF-4708671 may be considered as a potential drug for prostate cancer treatment.

Zhao Y, Scott A, Zhang P, et al.
Regulation of paxillin-p130-PI3K-AKT signaling axis by Src and PTPRT impacts colon tumorigenesis.
Oncotarget. 2017; 8(30):48782-48793 [PubMed] Free Access to Full Article Related Publications
Protein tyrosine phosphatase receptor T (PTPRT) is frequently mutated in a variety of human cancers including colorectal cancer. Here we report that PTPRT knockout increases the size of mouse colon tumors in the Apcmin+/- genetic background, suggesting that inactivation of PTPRT promotes tumor progression. We previously demonstrated that PTPRT dephosphorylates paxillin at tyrosine-Y88 residue. Consistently, phosphorylation of Y88 paxillin (pY88) is up-regulated in colon tumors derived from Apcmin+/- Ptprt-/- mice. An important downstream effector of pY88 paxillin is the oncogene Akt. Here, we show that pY88 paxillin impacts the Akt pathway by regulating the interaction between p130cas and the p85 regulatory subunit of PI3-Kinase. Additionally, while pY88 paxillin is a substrate of the tumor suppressor phosphatase PTPRT, the corresponding kinase has not been previously identified. In this study, we demonstrate that the oncogenic kinase Src directly phosphorylates paxillin at Y88. Moreover, colorectal cancer cells that express high levels of pY88 paxillin are sensitive to dasatinib treatment, suggesting that pY88 paxillin may serve as a predictive biomarker for Src family kinase inhibitors.

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