Gliomas are among the most frequent types of primary malignancies in the central nervous system. The main treatment for glioma includes surgical resection followed by a combination of radiotherapy and chemotherapy. Despite the availability of several treatments, the average survival for patients with glioma at advanced stages still remains 16 months only. Therefore, there is an urgent need to look for novel and more efficient drug candidates for the treatment of glioma. In the current study the anticancer activity of Mahanine was evaluated against a panel of glioma cells. The results revealed that Mahanine exerted significant anticancer effects on the glioma HS 683 cells with an IC

BACKGROUND: Nasopharyngeal carcinoma (NPC) is prevalent in South China, including Hong Kong and Southeast Asia, constantly associated with Epstein-Barr virus (EBV) infection. Epigenetic etiology attributed to EBV plays a critical role in NPC pathogenesis. Through previous CpG methylome study, we identified Disheveled-associated binding antagonist of beta-catenin 2 (DACT2) as a methylated target in NPC. Although DACT2 was shown to regulate Wnt signaling in some carcinomas, its functions in NPC pathogenesis remain unclear.
METHODS: RT-PCR, qPCR, MSP, and BGS were applied to measure expression levels and promoter methylation of DACT2 in NPC. Transwell, flow cytometric analysis, colony formation, and BrdU-ELISA assay were used to assess different biological functions affected by DACT2. Immunofluorescence, Western blot, and dual-luciferase reporter assay were used to explore the mechanisms of DACT2 functions. Chemosensitivity assay was used to measure the impact of DACT2 on chemotherapy drugs.
RESULTS: We found that DACT2 is readily expressed in multiple normal adult tissues including upper respiratory tissues. However, it is frequently downregulated in NPC and correlated with promoter methylation. DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine restored its expression in NPC cells. DACT2 methylation was further detected in 29/32 (91%) NPC tumors but not in any (0/8) normal nasopharyngeal tissue samples. Ectopic expression of DACT2 in NPC cells suppressed their proliferation, migration, and invasion through downregulating matrix metalloproteinases. DACT2 expression also induced G2/M arrest in NPC cells through directly suppressing β-catenin/Cdc25c signaling, which sensitized NPC cells to paclitaxel and 5-FU, but not cisplatin.
CONCLUSION: Our results demonstrate that DACT2 is frequently inactivated epigenetically by CpG methylation in NPC, while it inhibits NPC cell proliferation and metastasis via suppressing β-catenin/Cdc25c signaling. Our study suggests that DACT2 promoter methylation is a potential epigenetic biomarker for the detection and chemotherapy guidance of NPC.

Glioblastoma is the most common and lethal intracranial tumor type, characterized by high angiogenic and infiltrative capacities. To provide a novel insight into therapeutic strategies against glioblastoma, the cytotoxicity of arenobufagin and hellebrigenin was investigated in the human glioblastoma cell line, U-87. Similar dose-dependent cytotoxicity was observed in the cells, whereas no detectable toxicity was confirmed in mouse primary astrocytes. Treatment with each drug downregulated the expression levels of Cdc25C, Cyclin B1 and survivin, which occurred in parallel with G2/M phase arrest. Necrotic-like cell death was only observed in the cells treated with a relatively high concentration (>100 ng/ml). These results indicate that the two drugs exhibited distinct cytotoxicity against cancerous glial cells with high potency and selectivity, suggesting that growth inhibition associated with G2/M phase arrest and/or necrosis were attributed to their toxicities. Activation of the p38 mitogen activated protein kinase (MAPK) signaling pathway was also observed in treated cells. Notably, a specific inhibitor of p38 MAPK, SB203580, itself caused a significant decrease in cell viability, and further enhanced the cytotoxicity of the two drugs, suggesting an important pro-survival role for p38 MAPK. Given that p38 MAPK serves an essential role in promoting glioblastoma cell survival, developing a novel combination regimen of arenobufagin/hellebrigenin plus a p38 MAPK inhibitor may improve the efficacy of the two drugs, and may provide more therapeutic benefits to patients with glioblastoma. The qualitative assessment demonstrated the existence of arenobufagin in the cerebrospinal fluid of arenobufagin-treated rats, supporting its clinical application.

6-(methylsulfinyl) hexyl isothiocyanate (6-MITC) is a naturally occurring compound isolated from

ARID1A, a component of the SWI/SNF chromatin remodeling complex, is a tumor suppressor with a high frequency of inactivating mutations in many cancers. Therefore, ARID1A deficiency has been exploited therapeutically for treating cancer. Here we show that ARID1A has a synthetic lethal interaction with aurora kinase A (AURKA) in colorectal cancer (CRC) cells. Pharmacological and genetic perturbations of AURKA selectively inhibit the growth of ARID1A-deficient CRC cells. Mechanistically, ARID1A occupies the AURKA gene promoter and negatively regulates its transcription. Cells lacking ARID1A show enhanced AURKA transcription, which leads to the persistent activation of CDC25C, a key protein for G2/M transition and mitotic entry. Inhibiting AURKA activity in ARID1A-deficient cells significantly increases G2/M arrest and induces cellular multinucleation and apoptosis. This study shows a novel synthetic lethality interaction between ARID1A and AURKA and indicates that pharmacologically inhibiting the AURKA-CDC25C axis represents a novel strategy for treating CRC with ARID1A loss-of-function mutations.

Irinotecan, an analog of camptothecin, which is an inhibitor of topoisomerase I, is currently used in the treatment of metastatic colorectal cancer. Camptothecin derivatives have been demonstrated to exert radiosensitizing effects on several types of cancer cells. However, to date, at least to the best of our knowledge, few studies have examined these effects in colorectal cancer cell lines. In the present study, we examined the radiosensitizing effects of irinotecan on the p53-mutant colorectal cancer cell lines, HT29 and SW620, and explored the potential underlying mechanisms. Drug cytotoxicity tests revealed that the 24 h half-maximal inhibitory concentrations (IC50s) of irinotecan as a single agent were 39.84 µg/ml (HT29 95% CI, 38.27-41.48) and 96.86 µg/ml (SW620 95% CI, 89.04-105.4); finally, concentrations <2 µg/ml were used in the subsequent experiments. Clonogenic assays revealed that irinotecan exerted radiosensitizing effects on the HT29 and SW620 cells, and the sensitivity enhancement ratios (SERs) at 2 Gy increased with increasing concentrations (SER at 2 Gy, 1.41 for the HT29 cells, 1.87 for the SW620 cells; with irinotecan at 2 µg/ml). Subsequently, the cells were divided into 4 groups: The control group, irinotecan group, radiation group and combination group. Compared with the control, irinotecan and radiation groups, the combination group had the slowest cell growth rate and the most obvious foci of Ser139p‑γH2AX. Combined treatment resulted in a firstly decreased and then increased M phase arrest and led to the most significant G2/M phase arrest, followed by the most significant increase in apoptosis. The results of western blot analysis indicated that the expression levels of proteins related to the DNA damage response system (Ser1981p‑ATM, Ser345p‑Chk1, Thr68p‑Chk2 and Ser139p‑γH2AX) and the cell cycle (Tyr15p‑Cdc2 and cyclin B1) exhibited the greatest increase in the combined group. In addition, the expression of Ser216p‑Cdc25C was also increased in the combined group, indicating that irinotecan likely radiosensitized the p53-mutant HT29 and SW620 cells through the ATM/Chk/Cdc25C/Cdc2 pathway.

BACKGROUND: Glioblastoma (GBM) is the most common, malignant, and lethal primary brain tumor in adults accounting for about 50% of all gliomas. Up to now, the chemotherapy approaches for GBM were limited. 3-O-acetyl-11-keto-β-boswellic acid (AKBA), the major active ingredient of the gum resin from Boswellia serrata and Boswellia carteri Birdw., was reported to inhibit the growth of many types of cancer cells; however, the underlying mechanism of its anticancer effects are still unclear.
METHODS: The effects of AKBA on cell viability and its cytotoxicity were determined using CCK8 and LDH kits respectively. The EdU-DNA synthesis assay was used to evaluate inhibition of cell proliferation by AKBA. The role of AKBA in glioblastoma cell functions such as migration/invasion, and colony formation was evaluated using transwell chambers and soft agar, respectively. Flow cytometry and western blotting were used to detect AKBA-induced apoptosis. Potential mechanisms of AKBA action were explored by RNA sequencing and the identified hub genes were validated by real-time quantitative PCR and western blotting. Finally, the in vivo anti-tumor activity of AKBA was evaluated against a human glioblastoma cell line, U87-MG, in a xenograft mouse model.
RESULTS: AKBA inhibited cell proliferation, caused the release of LDH, decreased DNA synthesis, and inhibited the migration, invasion, and colony formation of U251 and U87-MG human glioblastoma cell lines. AKBA increased apoptosis as well as the activity of caspase 3/7 and the protein expression of cleaved-caspase 3 and cleaved PARP, while decreasing mitochondrial membrane potential. RNA-sequencing analyses showed that AKBA suppressed the expression of pRB, FOXM1, Aurora A, PLK1, CDC25C, p-CDK1, cyclinB1, Aurora B, and TOP2A while increasing the expression of p21 and GADD45A. These findings were validated by qRT-PCR and western blotting. The data are consistent with a mechanism in which AKBA arrested the cell cycle in glioblastoma cells at the G2/M phase by regulating the p21/FOXM1/cyclin B1 pathway, inhibited mitosis by downregulating the Aurora B/TOP2A pathway, and induced mitochondrial-dependent apoptosis. Oral administration of AKBA (100 mg/kg) significantly suppressed the tumorigenicity of U87-MG cells in a xenograft mouse model.
CONCLUSIONS: Taken together, these results suggest that AKBA (molecular weight, 512.7 Da) might be a promising chemotherapy drug in the treatment of GBM.

Previous studies have shown that high levels of PLK1 are expressed in HCC, and PLK1 inhibitors are being tested in clinical trials. However, the mechanisms, which regulate PLK1 expression in HCC, have not been clarified. Here, we show that induction of let-7b over-expression inhibits the PLK1-regulated luciferase activity in HEK-293T cells, and decreases the levels of PLK1 expression in HCC cells. Furthermore, the levels of let-7b expression were negatively correlated with PLK1 expression in HCC tissues. Let-7b over-expression inhibited the proliferation of HCC cells and promoted their apoptosis, which were partially rescued by increased PLK1 expression. Let-7b over-expression decreased the levels of PLK1, CDC25C and Survivin phosphorylation and CDC2, β-catenin, TCF-4 expression, which were mitigated by increased PLK1 expression in MHCC-97H cells. Let-7b over-expression inhibited the development and growth of implanted HCC tumors in mice by decreasing PLK1 and Survivin expression in the tumors. Together, our data indicated that let-7b targeted PLK1 to inhibit HCC growth and induce their apoptosis by attenuating the PLK1-mediated Survivin phosphorylation. Our findings may provide new insights into the pathogenesis of HCC.

Post-operative microwave (MW) hyperthermia has been applied as an important adjuvant therapy to enhance the efficacy of traditional cancer treatment. A better understanding of the molecular mechanisms of MW hyperthermia may provide guided and further information on clinical hyperthermia treatment. In this study, we examined the effects of MW hyperthermia on non‑small cell lung carcinoma (NSCLC) cells in vitro, as well as the underlying mechanisms. In order to mimic clinical treatment, we developed special MW heating equipment for this study. Various NSCLC cells (H460, PC-9 and H1975) were exposed to hyperthermia treatment using a water bath or MW heating system. The results revealed that MW hyperthermia significantly inhibited cell growth compared with the water bath heating system. Furthermore, MW hyperthermia increased the production of reactive oxygen species (ROS), decreased the levels of mitochondrial membrane potential (MMP) and induced caspase‑3 dependent apoptosis. It also induced G2/M phase arrest through the upregulation of the expression of phosphorylated (p‑) ataxia telangiectasia mutated (ATM), p‑checkpoint kinase 2 (Chk2) and p21, and the downregulation of the expression of cdc25c, cyclin B1 and cdc2. On the whole, the findings of this study indicate that the exposure of NSCLC cells to MW hyperthermia promotes caspase‑3 dependent apoptosis and induces G2/M cell cycle arrest via the ATM pathway. This preclinical study may help to provide laboratory-based evidence for MW hyperthermia treatment in clinical practice.

BACKGROUND/AIMS: Mutations in the Ras/Raf/MEK/ERK pathway are detected in 50% of colorectal cancer cases and play a crucial role in cancer development and progression. Cobimetinib is a MEK inhibitor approved for the treatment of advanced melanoma and inhibits the cell viability of other types of cancer cells.
METHODS: HCT116 colorectal cancer cells were treated with cobimetinib, and MTT assay, colony formation assay, and flow cytometry were used to evaluate cell viability, cell cycle, and apoptosis, respectively. The expression of genes associated with the cell cycle and apoptosis were evaluated by quantitative real-time PCR and western blotting. To explore use of cobimetinib in colorectal cancer treatment and further understand its mechanisms, RNA-seq technology was used to identify differentially expressed genes (DEGs) between cobimetinib-treated and untreated HCT116 cells. Furthermore, we compared these DEGs with Gene Expression Omnibus data from colorectal cancer tissues and normal colonic epithelial tissues.
RESULTS: We found that cobimetinib not only inhibited cell proliferation but also induced G1 phase arrest and apoptosis in HCT116 colorectal cancer cells, suggesting that cobimetinib may useful in colorectal cancer therapy. After cobimetinib treatment, 3,495 DEGs were obtained, including 2,089 upregulated genes and 1,406 downregulated genes, and most of these DEGs were enriched in the cell cycle, DNA replication, and DNA damage repair pathways. Our results revealed that some genes with high expression in colorectal cancer tissues were downregulated by cobimetinib in HCT116 cells, including CCND1, E2F1, CDC25C, CCNE2, MYC, and PCNA. These genes have vital roles in DNA replication and the cell cycle. Furthermore, genes with low expression in colorectal cancer tissues were upregulated by cobimetinib, including PRKCA, PI3K, RTK, and PKC. Based on our results, the PKC and PI3K pathways were activated after cobimetinib treatment, and inhibition of these two pathways can increase the cytotoxicity of cobimetinib in HCT116 cells. Notably, cobimetinib appeared to enhance the efficacy of 5-fluorouracil (5-FU) by decreasing TYMS expression, high expression of which is responsible for 5-FU resistance in colorectal cancer.
CONCLUSIONS: Our results suggest the potential use of cobimetinib in colorectal cancer therapy.

We synthesized and validated five Schiff base Pt(II) complexes derived from 2-hydroxy-1-naphthaldehyde benzoyl hydrazone and its derivatives, which are modified at the benzohydrazide structures (L1-L5). The complexes were [Pt(L1)(DMSO)Cl] (C1), [Pt(L2)(DMSO)Cl] (C2), [Pt(L3)(DMSO)Cl] (C3), [Pt(L4)(DMSO)Cl] (C4), and [Pt(L5)(DMSO)Cl] (C5). Crystal structures showed that the Pt centers of all complexes were tetra-coordinated with other atoms. The structure-activity relationships and anticancer mechanisms of the complexes were explored. These five Pt(II) complexes were toxic at micromolar doses and exhibited cytotoxicity similar to or somewhat higher than that of cisplatin, with IC

Head and neck squamous cell carcinoma (HNSCC) is a global disease and mortality burden, necessitating the elucidation of its molecular progression for effective disease management. The study aims to understand the molecular profile of three candidate cell cycle regulatory genes, RBSP3, LIMD1 and CDC25A in the basal/ parabasal versus spinous layer of normal oral epithelium and during head and neck tumorigenesis. Immunohistochemical expression and promoter methylation was used to determine the molecular signature in normal oral epithelium. The mechanism of alteration transmission of this profile during tumorigenesis was then explored through additional deletion and mutation in HPV/ tobacco etiological groups, followed byclinico-pathological correlation. In basal/parabasal layer, the molecular signature of the genes was low protein expression/ high promoter methylation of RBSP3, high expression/ low methylation of LIMD1 and high expression of CDC25A. Dysplastic epithelium maintained the signature of RBSP3 through high methylation/ additional deletion with loss of the signatures of LIMD1 and CDC25A via deletion/ additional methylation. Similarly, maintenance and / or loss of signature in invasive tumors was by recurrent deletion/ methylation. Thus, differential patterns of alteration of the genes might be pre-requisite for the development of dysplastic and invasive lesions. Etiological factors played a key role in promoting genetic alterations and determining prognosis. Tobacco negative HNSCC patients had significantly lower alterations of LIMD1 and CDC25A, along with better survival among tobacco negative/ HPV positive patients. Our data suggests the necessity for perturbation of normal molecular profile of RBSP3, LIMD1 and CDC25A in conjunction with etiological factors for head and neck tumorigenesis, implying their diagnostic and prognostic significance.

Head and neck squamous cell carcinoma is one of the leading cancers in terms of incidence and mortality. However, no reliable marker till date accurately predicts its progression when altered in healthy tissues. The study aims to identify alleles of microsatellites adjacent to important cell cycle regulatory, tumor suppressor genes altered in early head and neck lesions, viz. RBSP3, LIMD1 and CDC25A, which undergo frequent deletion and can be used for population screening and early detection. DNA for tumors and normal tissues was isolated from 143 patients in different stages of head and neck squamous cell carcinoma. The size of microsatellite present in normal tissues and their deletion in the corresponding tumor was identified, along with the correlation of expression in normal epithelium with respect to allele size. The results revealed a range of alleles (CA

Anthricin (deoxypodophyllotoxin) is a major lignan in Anthriscus sylvestris and possesses many bioactivities such as antiproliferative, antitumor, anti‑platelet aggregation, antiviral and anti‑inflammatory actions. However, the anticancer effects of anthricin on A549 human non‑small cell lung cancer cells and potential molecular mechanisms remain unknown. Therefore, we investigated the anticancer effect of anthricin and the underlying mechanism in A549 cells. Anthricin (10‑200 nM) inhibited the viability of A549 cells in a dose‑ and time‑dependent manner. Moreover, anthricin‑induced apoptosis was confirmed by live and dead assay, 4,6‑dianmidino‑2‑phenylindole staining, and flow cytometric analysis. In addition, anthricin induced cell cycle arrest at the G2/M phase through suppression of the expression of cell cycle cascade proteins, Cdc2 and Cdc25C. Furthermore, it induced the expression of caspase‑related proteins and significantly suppressed the phosphorylation of insulin‑like growth factor 1 receptor (IGF1R), PI3K and Akt. Anthricin significantly inhibited tumor growth without any significant change in the body weight of mice in A549 tumor xenograft BALB/c nude mice. Anthricin induced caspase‑dependent apoptosis through the IGF1R/PI3K/Akt signaling pathway in A549 cells.

BACKGROUND/AIMS: Hypoxia is a powerful stimulator of angiogenesis under physiological as well as pathological conditions. Normal endothelial cells (EC), such as human umbilical vein EC (HUVEC), are relatively affected by hypoxic insult in terms of cell survival. In contrast, EC from tumors are particularly resistant to hypoxia-induced cell death. Previous reports have shown that EC in bone marrow from multiple myeloma (MM) patients had a hypoxic phenotype, even under normoxic conditions. The aim of this study was to evaluate whether HUVEC and MMEC adapt differently to hypoxia.
METHODS: Cell proliferation was assessed by the CyQUANT assay. Cdc25A, p21, Bax, Bcl-xl, BNIP3, glucose transporter (GLUT)-1, monocarboxylate transporter (MCT)-4 and carbonic anhydrase (CA)IX mRNA expression was determined by qRT-PCR. HIF-1α, BNIP3, Beclin-1, LC3B, livin, Bax, Bcl-xl, p21, p62 and β-actin protein expression was analyzed by western blot. Apoptosis was determined by TUNEL assay. Silencing of BNIP3 was achieved by stealth RNA system technology.
RESULTS: While HUVEC survival was reduced after prolonged hypoxic exposure, MMEC were completely unaffected. This difference was also significant in terms of livin, cdc25A and p21 expression. Hypoxia induced apoptosis and inhibited autophagy in HUVEC, but not in MMEC, where hypoxic treatment resulted in a more sustained adaptive response. In fact, MMEC showed a more significant increase in the expression of genes regulated transcriptionally by hypoxia-inducible factor (HIF)-1α. Interestingly, they showed higher expression of BNIP3 than did HUVEC, indicating a more pronounced autophagic (and pro-survival) phenotype. The potential role of BNIP3 in EC survival was confirmed by BNIP3 siRNA experiments in HUVEC, where BNIP3 inhibition resulted in reduced cell survival and increased apoptosis.
CONCLUSION: These findings provide further information on how hypoxia may affect EC survival and could be important for a better understanding of EC physiology under normal and pathological conditions, such as in multiple myeloma.

BACKGROUND Colorectal cancer (CRC) is the third most common cancer worldwide, making it is a serious threat to human health. It is imperative to develop new therapeutics to improve the CRC treatment efficiency. The aim of this study was to investigate the role of NPRL2 in improving sensitivity to CPT-11 in colon cancer cells. MATERIAL AND METHODS NPRL2 overexpression was established by transfecting the recombinant lentivirus-encoding NPRL2 gene into HCT116 colon cancer cells. Cell proliferation was identified using Cell Counting Kit-8 (CCK8) assay. Cell cycle and apoptosis were examined by flow cytometry. An immunofluorescence staining assay was conducted to examine the expression of γ-H2AX. Wound-healing and Transwell assays were utilized to show cell migration and invasion capability. The expression of apoptosis-related proteins (cleaved caspase-3, caspase-9, cleaved PARP, BAX, and Bcl-2), invasion-related proteins (MMP2, MMP9, p-PI3K, and p-AKT), and DNA damage checkpoint pathway proteins (p-ATM, p-Chk2, Cdc25C, Cdc2, and Cyclin B1) were quantified by Western blotting. RESULTS A CCK8 assay revealed that the overexpression of NPRL2 improved the sensitivity of CPT-11 in HCT116 cells (P<0.05). Functionally, NPRL2 overexpression elevated the sensitivity of CPT-11 by preventing colon cancer cell proliferation, cell movement, and invasion, and promoting cell apoptosis and G2/M cell cycle arrest. Mechanistically, NPRL2 overexpression enhanced CPT-11 sensitivity by activating the DNA damage checkpoint pathway. CONCLUSIONS NPRL2 overexpression enhances sensitivity to CPT-11 treatment in colon cancer cells, and it may serve as a molecular therapeutic agent to treat patients with CRC.

The most common therapy for estrogen receptor-positive breast cancer is antihormone therapy, such as tamoxifen. However, acquisition of resistance to tamoxifen in one third of patients presents a serious clinical problem. Polo-like kinase 1 (Plk1) is a key oncogenic regulator of completion of G

BRCA2 is essential for maintaining genomic integrity. BRCA2-deficient primary cells are either not viable or exhibit severe proliferation defects. Yet, BRCA2 deficiency contributes to tumorigenesis. It is believed that mutations in genes such as TRP53 allow BRCA2 heterozygous cells to overcome growth arrest when they undergo loss of heterozygosity. Here, we report the use of an insertional mutagenesis screen to identify a role for BRE (Brain and Reproductive organ Expressed, also known as BRCC45), known to be a part of the BRCA1-DNA damage sensing complex, in the survival of BRCA2-deficient mouse ES cells. Cell viability by BRE overexpression is mediated by deregulation of CDC25A phosphatase, a key cell cycle regulator and an oncogene. We show that BRE facilitates deubiquitylation of CDC25A by recruiting ubiquitin-specific-processing protease 7 (USP7) in the presence of DNA damage. Additionally, we uncovered the role of CDC25A in BRCA-mediated tumorigenesis, which can have implications in cancer treatment.

DN604, a carboplatin analogue with a functional dicarboxylato ligand, was deeply investigated to explore its ability to induce apoptosis as well as its antitumor mechanism of action. Both in vitro and in vivo assays indicated that DN604 could effectively inhibit cell viability of SGC-7901 gastric cancer cells and exhibited stronger antitumor activity than carboplatin and comparable activity to cisplatin. Significantly in contrast to cisplatin, DN604 resulted in negligible toxic effects in vivo with the same tumor growth inhibition effect as cisplatin. The mechanism study indicated that DN604 inhibited CK2-phosphorylated cdc25C activation to decrease p-cdc25C subcellular localization, leading to the inactivation of cdc2/Cyclin B and G2/M cell cycle arrest and apoptosis in SGC-7901 cancer cells. Our research revealed for the first time that the dicarboxylato ligand containing a suitable functional moiety as the leaving group in the platinum(II) complex can effectively induce cell cycle arrest and apoptosis via inhibiting key checkpoint proteins.

microRNA-152 (miR-152) is a tumor suppressor that is down-regulated in many cancers including endometrial cancer (EC). However, the underlying mechanism of action of miR-152 in EC is unclear. The aim of the present study was to evaluate the role of miR-152 on proliferation of human endometrial cancer cells. Herein, we found that miR-152 overexpression and CDC25B knockdown inhibited proliferative ability and induced G2/M phase arrest in KLE and HEC-1B cells. CDC25B was a target of miR-152. In addition, CDC25B overexpression rescued miR-152-induced proliferation inhibition and G2/M phase arrest in human endometrial cancer cells. The results indicated that miR-152 was a tumor suppressor in EC that inhibited proliferation of human endometrial cancer cells via inducing G2/M phase arrest by suppressing CDC25B expression.

Butein is a biologically active flavonoid isolated from the bark of Rhus verniciflua Stokes, which is known to have therapeutic potential against various cancers. Notably, butein inhibits cancer cell growth by inducing G

In the cell cycle, there are two checkpoint arrests that allow cells to repair damaged DNA in order to maintain genomic integrity. Many cancer cells have defective G1 checkpoint mechanisms, thus depending on the G2 checkpoint far more than normal cells. G2 checkpoint abrogation is therefore a promising concept to preferably damage cancerous cells over normal cells. The main factor influencing the decision to enter mitosis is a complex composed of Cdk1 and cyclin B. Cdk1/CycB is regulated by various feedback mechanisms, in particular inhibitory phosphorylations at Thr14 and Tyr15 of Cdk1. In fact, Cdk1/CycB activity is restricted by the balance between WEE family kinases and Cdc25 phosphatases. The WEE kinase family consists of three proteins: WEE1, PKMYT1, and the less important WEE1B. WEE1 exclusively mediates phosphorylation at Tyr15, whereas PKMYT1 is dual-specific for Tyr15 as well as Thr14. Inhibition by a small molecule inhibitor is therefore proposed to be a promising option since WEE kinases bind Cdk1, altering equilibria and thus affecting G2/M transition.

Small cell lung cancer (SCLC) is a difficult to treat subtype of lung cancer. One of the hallmarks of SCLC is its almost uniform chemotherapy sensitivity. However, chemotherapy response is typically transient and patients frequently succumb to SCLC within a year following diagnosis. We performed a transcriptome analysis of the major human lung cancer entities. We show a significant overexpression of genes involved in the DNA damage response, specifically in SCLC. Particularly CHEK1, which encodes for the cell cycle checkpoint kinase CHK1, is significantly overexpressed in SCLC, compared to lung adenocarcinoma. In line with uncontrolled cell cycle progression in SCLC, we find that CDC25A, B and C mRNAs are expressed at significantly higher levels in SCLC, compared to lung adenocarcinoma. We next profiled the efficacy of compounds targeting CHK1 and ATR. Both, ATR- and CHK1 inhibitors induce genotoxic damage and apoptosis in human and murine SCLC cell lines, but not in lung adenocarcinoma cells. We further demonstrate that murine SCLC tumors were highly sensitive to ATR- and CHK1 inhibitors, while Kras

Augmenter of liver regeneration (ALR) plays crucial roles in cell survival and growth. Previous studies have demonstrated that ALR exerts a protective effect on toxic agent‑induced cell death in acute T lymphoblastic leukemia cells and ALR knockdown can sensitize cancer cells to radiation. However, the biological functions of ALR against drug resistance in T-cell acute lymphoblastic leukemia are mostly unknown. In the present study, we investigated the effect of small interfering RNA (siRNA)-induced ALR silencing on cell proliferation and sensitivity to vincristine (VCR) of Jurkat cells. We found that ALR siRNA effectively decreased the ALR expression, then inhibited cell growth and increased sensitivity to VCR in Jurkat cells. Flow cytometry assay revealed that the downregulation of ALR expression promoted cell apoptosis and regulated cell cycle distribution. Following incubation with VCR, apoptosis-related proteins, such as pro-PARP, pro-caspase 8, pro-caspase 3 and Bcl-2 were downregulated in the siRNA/ALR group. Pretreatment with siRNA/ALR in combination with VCR resulted in prolonged G2/M arrest, accompanied by downregulation of cdc25c and cdc2 expression and dissociation of cyclin B1. In conclusion, the results of this study demonstrated that targeted inhibition of the ALR expression in Jurkat cells triggered cell growth inhibition and sensitized cells to VCR via promoting apoptosis and regulating the cell cycle.

BACKGROUND: Dysregulation of microRNA(miRNAs) expression was reported in human esophageal squamous cell carcinoma (ESCC). MiR-214 has been found to acts as a tumor suppressor in some tumors including ESCC. The objective of the study was to investigate the functional effect of miR-214 on the regulation of human ESCC progression.
METHODS: The expression levels of miR-214 in 57 paired human ESCC tissues and adjacent normal tissues were examined by qRT-PCR. The capacities of cell proliferation and invasion were determined after up-regulation or down-regulation of miR-214 by performing cell viability assay, colony formation assay and transwell assay. Dual luciferase assays, Western blot analysis and qRT-PCR assay were used to demonstrate the association between CDC25B and miR-214. Western blot analysis assessed relative CDC25B protein expression.
RESULTS: We observed that miR-214 expression exhibited a frequent down-regulation in ESCC tissues and cells, compared to adjacent normal tissues and cells, respectively. Furthermore, up-regulation of miR-214 significantly inhibited cell proliferation and colony formation and cell invasion capacities in Eca9706 and Eca109 cells. However, down-regulation of miR-214 exhibited an opposite effects. Dual luciferase assays showed that CDC25B was identified as a direct target of miR-214. Meanwhile, up-regulation of miR-214 decreased CDC25B expression, whereas, down-regulation of miR-214 increased the CDC25B expression in Eca9706 and Eca109 cells. Moreover, we demonstrated that miR-214 inhibited Eca9706 and Eca109 cells proliferation and invasion through CDC25B.
CONCLUSION: Our results indicate that miR-214 function as a tumor suppressor and may be potential therapeutic target for ESCC.

Despite its documented role in cell cycle regulation, over-expression of the cyclin-dependent kinase activator CDC25A does not consistently correlate with worse cancer patient outcomes or predict successful clinical response to CDC25A inhibition. The current study was undertaken to investigate CDC25A in skin cancer and understand predictors of positive response to CDC25A targeting. CDC25A was increased in human squamous cell carcinoma (SCC) associated with a shift from a primarily nuclear localization in skin to a strong cytoplasmic localization in SCC, a pattern that was reproduced in skin cancer cell lines. Surprisingly, siRNA-targeting or forced expression of CDC25A failed to alter SCC proliferation. Instead, CDC25A suppressed apoptotic cell death in a manner dependent on both its cytoplasmic localization and interaction with 14-3-3. Normal keratinocytes with nuclear localization of the phosphatase were resistant to CDC25A modulation. Additionally, the CDC25A inhibitors Vitamin K3 or NSC663284 were more toxic to SCC than normal keratinocytes, and CDC25A inhibition effectively suppressed skin cancer growth by increasing apoptosis without affecting normal skin biology. These studies provide proof-of-concept evidence for the potential of CDC25A inhibitors for skin cancer treatment and suggest that an assessment of the cytoplasmic localization of CDC25A may be a strategy for identification of skin and other cancers susceptible to CDC25A targeting.

BACKGROUND: Upregulation of Cyclin dependent kinase 1 (CDK1) protein is closely related with the prognosis of several malignant tumors. Chk1-CDC25C-CDK1 signaling and P53-P21WAF1-CDK1 signaling pathways are closely related with the cell cycle G2/M phase regulation. The present study aimed to analyze the relationship between CDK1 and the proliferation and apoptosis of ovarian cancer cells, investigate its molecular mechanism preliminarily.
METHODS: The specific short-hair RNA (shRNA) plasmids and negative control plasmid of CDK1, checkpoint kinase 1 (CHK1) and p53 genes were transfected into ovarian cancer SK-OV-3 and OVCAR-3 cells respectively. The expressions of CDK1, CHK1 and p53 mRNA and CDK1, Chk1 and P53 protein were detected by sqRT-PCR and Western blot, levels of phospho-CDK1(Thr14/Tyr15), CyclinB1, phospho-Chk1(ser345), cell division cycle 25C (CDC25C), phospho-CDC25C(ser216), P21WAF1, phospho-P53(ser15), proliferating cell nuclear antigen (PCNA), Ki-67, Bcl-2, Bax, Caspase8, Cleaved-caspase3 and Cytochrome C were examined by Western blot. The cell proliferation was measured by MTT and Trypan blue exclusion assay respectively, the cell cycle phase distribution and cell apoptosis rate were detected by flow cytometry (FCM) assay.
RESULTS: As results of CDK1 inhibition by shRNA, the cell proliferation was repressed, the cell numbers of G2/M phase and cell apoptosis rate were increased in both SK-OV-3 and OVCAR-3 cells. After knockdown of CDK1, expressions of PCNA, Ki-67 and Bcl-2 protein were downregulated, expressions of Bax, Caspase8, Cleaved-caspase3 and Cytochrome C were upregulated. While knockdown the CHK1 and p53 by shRNA respectively, the similar effects were observed on the cell proliferation, cell cycle phase distribution and apoptosis in both SK-OV-3 and OVCAR-3 cells, as well as the expressions of the proliferation and apoptosis related proteins mentioned above. Moreover, the levels of p-CDK1(Thr14/Tyr15) were increased after either CHK1 inhibition or p53 inhibition.
CONCLUSIONS: Abnormal activation of CDK1 was implicated in the proliferation and apoptosis regulation of ovarian cancer cells, which might be due to the aberrant regulations of the upstream Chk1-CDC25C and P53-P21WAF1 signaling pathway.

Cell cycle dysregulation leads to uncontrolled cell proliferation and tumorigenesis. Understanding the molecular mechanisms underlying cell cycle progression can provide clues leading to the identification of key proteins involved in cancer development. In this study, we performed proteomics analysis to identify novel regulators of the cell cycle. We found that potassium channel tetramerization domain containing 12 (KCTD12) was significantly upregulated in M phase compared with S phase. We also found that KCTD12 overexpression not only facilitated the G2/M transition and induced cancer cell proliferation, but also promoted the growth of subcutaneous tumors and Ki-67 proliferation index in mice. Regarding the mechanism underlying these phenomena, cyclin-dependent kinase 1 (CDK1) was identified as an interacting partner of KCTD12 by immunoprecipitation and mass spectrometry analysis, which showed that KCTD12 activated CDK1 and Aurora kinase A (Aurora A) and that the effects of KCTD12 on CDK1 phosphorylation and cell proliferation were abrogated by cell division cycle 25B (CDC25B) silencing. In addition, Aurora A phosphorylated KCTD12 at serine 243, thereby initiating a positive feedback loop necessary for KCTD12 to exert its cancer-promoting effects. Furthermore, we analyzed the expression levels of various genes and the correlations between the expression of these genes and survival using tumor tissue microarray and Gene Expression Omnibus (GEO) data sets. The data showed that KCTD12 expression was significantly upregulated in cervical and lung cancers. More importantly, high KCTD12 expression was associated with larger tumor sizes, higher pathological stages and poor patient survival. Collectively, our study demonstrate that KCTD12 binds to CDC25B and activates CDK1 and Aurora A to facilitate the G2/M transition and promote tumorigenesis and that Aurora A phosphorylates KCTD12 at serine 243 to trigger a positive feedback loop, thereby potentiating the effects of KCTD12. Thus, the KCTD12-CDC25B-CDK1-Aurora A axis has important implications for cancer diagnoses and prognoses.

The aim of the present study was to clarify the clinical implication and functional role of tripartite motif-59 (TRIM59) in colorectal carcinoma (CRC) and explore the underlying mechanism of aberrant high expression of TRIM59 in cancer. We validated that TRIM59 was upregulated in CRC samples, and also demonstrated that its upregulation was associated with advanced tumor stage of CRC patients; and its high expression indicated shorter overall survival and faster recurrence. Knockdown of TRIM59 significantly inhibited cell proliferation, migration and invasion. Cell cycle analysis showed that TRIM59-depleted cells accumulated in S-phase. In addition, the cell cycle regulators CDC25C, cyclin B1 and cyclin D1 were decreased by TRIM59 siRNA mediated knockdown. Furthermore, the depletion of TRIM59 promoted apoptosis in cell culture as indicated by the cleavage of caspase-3 and PARP when TRIM59 was depleted. These results suggested that TRIM59 is upregulated in human colorectal tumors compared with non-tumor tissues. The level of TRIM59 is correlated with malignant features of CRC and may serve as potential therapeutic and preventive strategies for CRC.

Non-small cell lung carcinoma (NSCLC) is the most common lung cancer with high morbidity and mortality. The traditional treatment for NSCLC is particularly liable to relapse with many side-effects. Barbaloin is a natural compound with anticancer efficacy. The present study aimed to investigate the anticancer potential of barbaloin in NSCLC. The results displayed that barbaloin inhibited the viability of A549 cells by decreasing cell growth and the expression level of Ki-67 and proliferating cell nuclear antigen (PCNA), especially at high concentrations (50 and 100 µM). Besides, barbaloin increased the apoptosis rate of A549 cells and induced an accumulation of G2/M phase. Increased expression of apoptosis-related proteins (caspase-3, -8 and -9) and the changed levels of cell cycle checkpoint proteins (p27, p53 and cyclin A) further convinced of the anti-viability effect of barbaloin in A549 cells. On the other hand, barbaloin significantly suppressed the invasion and migration of A549 cells, and restrained the expression of tumor metastasis-related proteins. We further explored the activation of pro-survival or pro-metastasis signaling pathways, including AKT, nuclear factor kappa B (NF-κB), mitogen-actived protein kinase (MAPK) and β-catenin. The results revealed that barbaloin inactivated the p38MAPK/Cdc25B/Hsp27 pathway by inhibiting p38 nucleus translocation, while no significant influence was observed among other pathways. Finally, barbaloin restrained the growth and hepatic metastases of A549 cells in vivo. Taken together, our research indicated that barbaloin inhibited the proliferation and metastasis of NSCLC cells in vivo and in vitro. This may provide safer and more effective aspects for the treatment of NSCLC.