CRTC1

Gene Summary

Gene:CRTC1; CREB regulated transcription coactivator 1
Aliases: MAML2, MECT1, Mam-2, TORC1, TORC-1, WAMTP1
Location:19p13.11
Summary:-
Databases:OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:CREB-regulated transcription coactivator 1
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.

  • Translocation
  • Salivary Gland Cancer
  • Gene Expression Profiling
  • Cyclic AMP Response Element-Binding Protein
  • ErbB Receptors
  • Messenger RNA
  • Sweat Gland Neoplasms
  • Gene Rearrangement
  • Phosphorylation
  • RTPCR
  • Nuclear Proteins
  • Chromosome 11
  • Chromosome 19
  • Adenoma, Pleomorphic
  • Childhood Cancer
  • DNA-Binding Proteins
  • Signal Transduction
  • Genetic Predisposition
  • Young Adult
  • Adolescents
  • Disease Models, Animal
  • Differential Diagnosis
  • Cervical Cancer
  • Gene Fusion
  • Single Nucleotide Polymorphism
  • Tumor Suppressor Proteins
  • Immunohistochemistry
  • HEK293 Cells
  • Carcinoma, Mucoepidermoid
  • Biomarkers, Tumor
  • Transcription Factors
  • Mutation
  • Tuberous Sclerosis
  • Oncogene Fusion Proteins
  • rho GTP-Binding Proteins
  • tuberous sclerosis complex 2 protein
  • Adenolymphoma
  • Cancer Gene Expression Regulation
  • FISH
  • Lung Cancer
Tag cloud generated 30 August, 2019 using data from PubMed, MeSH and CancerIndex

Specific Cancers (4)

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: CRTC1 (cancer-related)

Zhang D, Liao X, Tang Y, et al.
Warthin-like Mucoepidermoid Carcinoma of the Parotid Gland: Unusual Morphology and Diagnostic Pitfalls.
Anticancer Res. 2019; 39(6):3213-3217 [PubMed] Related Publications
BACKGROUND: Warthin-like mucoepidermoid carcinoma is a newly recognized rare entity and could be misdiagnosed as a benign Warthin tumor. We report such a case of a 36-year-old male who presented with a left parotid gland mass.
CASE REPORT: Fine-needle aspiration showed features suggestive of Warthin tumor. Following parotidectomy, grossly there was a 1.6 cm well-circumscribed multilobular mass with focal areas of cystic change. Microscopically, at low magnification it had histological features resembling Warthin tumor, while lining with squamoid cells with scattered mucocytes demonstrating mild cytologic atypia was observed at high magnification. Immunohistochemically, the tumor cells were positive for p40, p63, cytokeratin 5/6, cytokeratin 7, and cancer antigen 125, but negative for discovered on GIST-1 (DOG1). Mucicarmine stain highlighted intracellular mucin within mucocytes. Rearrangement of mastermind like transcriptional coactivator 2 (MAML2) (11q21) gene was shown to be present in tumor cells by fluorescence in situ hybridization, supporting the diagnosis of a low-grade Warthin-like mucoepidermoid carcinoma. The patient was disease-free 12 months after surgery.
CONCLUSION: Warthin-like mucoepidermoid carcinoma has not been widely recognized and can be misdiagnosed as Warthin tumor. Testing for MAML2 rearrangement provides essential support for diagnosis in difficult cases.

Picco G, Chen ED, Alonso LG, et al.
Functional linkage of gene fusions to cancer cell fitness assessed by pharmacological and CRISPR-Cas9 screening.
Nat Commun. 2019; 10(1):2198 [PubMed] Free Access to Full Article Related Publications
Many gene fusions are reported in tumours and for most their role remains unknown. As fusions are used for diagnostic and prognostic purposes, and are targets for treatment, it is crucial to assess their function in cancer. To systematically investigate the role of fusions in tumour cell fitness, we utilized RNA-sequencing data from 1011 human cancer cell lines to functionally link 8354 fusion events with genomic data, sensitivity to >350 anti-cancer drugs and CRISPR-Cas9 loss-of-fitness effects. Established clinically-relevant fusions were identified. Overall, detection of functional fusions was rare, including those involving cancer driver genes, suggesting that many fusions are dispensable for tumour fitness. Therapeutically actionable fusions involving RAF1, BRD4 and ROS1 were verified in new histologies. In addition, recurrent YAP1-MAML2 fusions were identified as activators of Hippo-pathway signaling in multiple cancer types. Our approach discriminates functional fusions, identifying new drivers of carcinogenesis and fusions that could have clinical implications.

Lupinacci FCS, Kuasne H, Roffé M, et al.
Polysome Profiling of a Human Glioblastoma Reveals Intratumoral Heterogeneity.
Int J Mol Sci. 2019; 20(9) [PubMed] Free Access to Full Article Related Publications
Glioblastoma (GBM) is one of the most aggressive cancers, with median survival of less than 2 years. Despite of considerable advance in molecular classification of GBMs, no improvements in therapy have been described. The scenario is further complicated by tumor heterogeneity and the relationship among genetic, transcriptional and functional findings. Classically, gene expression has been evaluated by steady-state mRNA, however, this does not take translational control into consideration, which contributes considerably to the composition of the proteome. In this study, we evaluated the transcriptomic and translatomic signature of a GBM obtained from a single patient focusing in tumor heterogeneity. In a sampling of eight fragments, we investigated the translation rates, mTORC1 and ERK1/2 pathways and identified both total and polysome associated mRNAs. An increased translation rate was observed in fragments with high-grade histological features. High-grade histology was also associated with the expression of genes related to extracellular matrix (ECM) and angiogenesis, in both transcriptomes and translatomes. However, genes associated with epithelial to mesenchymal transition and stress response, were observed only in translatomes from high-grade fragments. Overall, our results demonstrate that isolation of translated mRNA can be used to identify biomarkers and reveal previously unrecognized determinants of heterogeneity in GBMs.

Saccà CD, Gorini F, Ambrosio S, et al.
Inhibition of lysine-specific demethylase LSD1 induces senescence in Glioblastoma cells through a HIF-1α-dependent pathway.
Biochim Biophys Acta Gene Regul Mech. 2019; 1862(5):535-546 [PubMed] Related Publications
Senescence is a stress-responsive cellular program that leads to cell cycle arrest. In cancer cells, senescence has profound implications for tumor aggressiveness and clinical outcome, but the molecular events that provoke cancer cells to undergo senescence remain unclear. Herein, we provide evidence that the histone demethylase LSD1/KDM1A supports the growth of Glioblastoma tumor cells and its inhibition triggers senescence response. LSD1 is a histone modifier that participates in key aspects of gene transcription as well as in the regulation of methylation dynamics of non-histone proteins. We found that down-regulation of LSD1 inhibits Glioblastoma cell growth, impairs mTOR pathway and cell migration and induces senescence. At mechanistic level, we found that LSD1 regulates HIF-1α protein stability. Pharmacological inhibition or siRNA-mediated silencing of LSD1 expression effectively reduces HIF-1α protein levels, which suffices for the induction of senescence. Our findings elucidate a mechanism whereby LSD1 controls senescence in Glioblastoma tumor cells through the regulation of HIF-1α, and we propose the novel defined LSD1/HIF-1α axis as a new target for the therapy of Glioblastoma tumors.

Qie S, Yoshida A, Parnham S, et al.
Targeting glutamine-addiction and overcoming CDK4/6 inhibitor resistance in human esophageal squamous cell carcinoma.
Nat Commun. 2019; 10(1):1296 [PubMed] Free Access to Full Article Related Publications
The dysregulation of Fbxo4-cyclin D1 axis occurs at high frequency in esophageal squamous cell carcinoma (ESCC), where it promotes ESCC development and progression. However, defining a therapeutic vulnerability that results from this dysregulation has remained elusive. Here we demonstrate that Rb and mTORC1 contribute to Gln-addiction upon the dysregulation of the Fbxo4-cyclin D1 axis, which leads to the reprogramming of cellular metabolism. This reprogramming is characterized by reduced energy production and increased sensitivity of ESCC cells to combined treatment with CB-839 (glutaminase 1 inhibitor) plus metformin/phenformin. Of additional importance, this combined treatment has potent efficacy in ESCC cells with acquired resistance to CDK4/6 inhibitors in vitro and in xenograft tumors. Our findings reveal a molecular basis for cancer therapy through targeting glutaminolysis and mitochondrial respiration in ESCC with dysregulated Fbxo4-cyclin D1 axis as well as cancers resistant to CDK4/6 inhibitors.

Pal R, Xiong Y, Sardiello M
Abnormal glycogen storage in tuberous sclerosis complex caused by impairment of mTORC1-dependent and -independent signaling pathways.
Proc Natl Acad Sci U S A. 2019; 116(8):2977-2986 [PubMed] Free Access to Full Article Related Publications
Tuberous sclerosis complex (TSC) is an autosomal dominant syndrome that causes tumor formation in multiple organs. TSC is caused by inactivating mutations in the genes encoding TSC1/2, negative regulators of the mammalian target of rapamycin complex 1 (mTORC1). Diminished TSC function is associated with excess glycogen storage, but the causative mechanism is unknown. By studying human and mouse cells with defective or absent TSC2, we show that complete loss of TSC2 causes an increase in glycogen synthesis through mTORC1 hyperactivation and subsequent inactivation of glycogen synthase kinase 3β (GSK3β), a negative regulator of glycogen synthesis. Specific TSC2 pathogenic mutations, however, result in elevated glycogen levels with no changes in mTORC1 or GSK3β activities. We identify mTORC1-independent lysosomal depletion and impairment of autophagy as the driving causes underlying abnormal glycogen storage in TSC irrespective of the underlying mutation. The defective autophagic degradation of glycogen is associated with abnormal ubiquitination and degradation of essential proteins of the autophagy-lysosome pathway, such as LC3 and lysosomal associated membrane protein 1 and 2 (LAMP1/2) and is restored by the combined use of mTORC1 and Akt pharmacological inhibitors. In complementation to current models that place mTORC1 as the central therapeutic target for TSC pathogenesis, our findings identify mTORC1-independent pathways that are dysregulated in TSC and that should therefore be taken into account in the development of a therapeutic treatment.

Wang R, Liu Y, Liu L, et al.
Tumor cells induce LAMP2a expression in tumor-associated macrophage for cancer progression.
EBioMedicine. 2019; 40:118-134 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Tumor cells benefit from tumor-associated macrophages (TAMs) promoting tumor growth and modulating functions of other cells in tumor microenvironment (TME). However, how tumor cells regulate the property of TAMs during tumor invasion remains to be defined.
METHODS: Mouse tumor models and cancer patients' samples were analyzed to determine LAMP2a expression in TAMs. In vitro mouse primary macrophages were used to assess LAMP2a-modulated macrophage activation, and to verify LAMP2a's target proteins. The effect of LAMP2a-knockdown on tumor progression and TME maintaining was determined by using mouse tumor models.
FINDINGS: Lysosome associated membrane protein type 2A (LAMP2a) is upregulated in TAMs by tumor cells and important for tumor progression. LAMP2a expression in TAMs, but not in tumor cells, is associated with poor prognosis in breast cancer. LAMP2a inactivation induced by either shRNA or CRISPR/Cas9 prevents TAMs activation and tumor growth. LAMP2a degrades PRDX1 (peroxiredoxin 1) and CRTC1 (CREB-regulated transcription coactivator 1) to promote macrophage pro-tumorigenic activation.
INTERPRETATION: Our study suggests that tumor cells utilize LAMP2a-PRDX1/CRTC1 axis to modulate TAMs activation and promote tumor growth, reveals the role of LAMP2a in macrophage study and TAM-targeting tumor immunotherapy. FUND: National Natural Science Foundation of China (No. 81602492); National Key Research and Development Program of China (No. 2016YFA0201402).

Yorita K, Nakagawa H, Miyazaki K, et al.
Infarcted Warthin tumor with mucoepidermoid carcinoma-like metaplasia: a case report and review of the literature.
J Med Case Rep. 2019; 13(1):12 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Warthin tumor is a common, benign, painless salivary gland neoplasm. Rarely, Warthin tumors show large areas of squamous metaplasia; such Warthin tumors are called metaplastic or infarcted Warthin tumors because they are occasionally accompanied with tumor necrosis. The histological distinction between mucoepidermoid carcinomas and the metaplastic portions of Warthin tumors can be challenging; without a genetic study, mucoepidermoid carcinomas can be misdiagnosed as metaplastic Warthin tumors. We report a case of infarcted Warthin tumor partly showing mucoepidermoid carcinoma-like epithelial metaplasia. Only two cases of infarcted Warthin tumor similar to our case have been reported.
CASE PRESENTATION: A 69-year-old Japanese man presented with a right parotid tumor. He had noticed the swelling on his right buccal region 1 year previously; the lesion had rapidly enlarged, with associated pain, 1 month previously. A radiological examination revealed a mass in the tail of the right parotid gland. Superficial parotidectomy was performed. On histological examination, the mass showed typical focal features of Warthin tumor; other areas showed coagulation necrosis of the tumor. These areas were surrounded by non-oncocytic epithelium comprising squamous and mucinous epithelial cells. Although cellular atypia of the non-oncocytic epithelium was not observed, a mixture of squamous and mucinous cells and lack of abundant lymphoid tissue mimicked low-grade mucoepidermoid carcinoma. Based on the results of fluorescence in situ hybridization, MAML2 gene rearrangement was not present in the typical portions of Warthin tumor and the mucoepidermoid carcinoma-like lesion. Therefore, a metaplastic or infarcted Warthin tumor was diagnosed. Our patient was disease-free 8 months after surgery.
CONCLUSIONS: Clinicians need to know that pain is a clinical symptom of infarcted/metaplastic Warthin tumor. Pathologists should be aware that a metaplastic Warthin tumor can mimic a low-grade mucoepidermoid carcinoma. Our case showed a mucoepidermoid carcinoma-like lesion that was confined near the area of tumor necrosis, and neither cytological atypia nor apparent invasive growth was present. These findings appeared to be histological clues of a metaplastic Warthin tumor rather than a mucoepidermoid carcinoma. Careful clinicopathological evaluation as well as genetic studies are needed to clarify the distinction between mucoepidermoid carcinoma and metaplastic portions of Warthin tumors.

Cuesta R, Berman AY, Alayev A, Holz MK
Estrogen receptor α promotes protein synthesis by fine-tuning the expression of the eukaryotic translation initiation factor 3 subunit f (eIF3f).
J Biol Chem. 2019; 294(7):2267-2278 [PubMed] Article available free on PMC after 15/02/2020 Related Publications
Approximately two thirds of all breast cancer cases are estrogen receptor (ER)-positive. The treatment of this breast cancer subtype with endocrine therapies is effective in the adjuvant and recurrent settings. However, their effectiveness is compromised by the emergence of intrinsic or acquired resistance. Thus, identification of new molecular targets can significantly contribute to the development of novel therapeutic strategies. In recent years, many studies have implicated aberrant levels of translation initiation factors in cancer etiology and provided evidence that identifies these factors as promising therapeutic targets. Accordingly, we observed reduced levels of the eIF3 subunit eIF3f in ER-positive breast cancer cells compared with ER-negative cells, and determined that low eIF3f levels are required for proper proliferation and survival of ER-positive MCF7 cells. The expression of eIF3f is tightly controlled by ERα at the transcriptional (genomic pathway) and translational (nongenomic pathway) level. Specifically, estrogen-bound ERα represses transcription of the

Rogers-Broadway KR, Kumar J, Sisu C, et al.
Differential expression of mTOR components in endometriosis and ovarian cancer: Effects of rapalogues and dual kinase inhibitors on mTORC1 and mTORC2 stoichiometry.
Int J Mol Med. 2019; 43(1):47-56 [PubMed] Article available free on PMC after 15/02/2020 Related Publications
Endometriosis is a well‑known risk factor for ovarian cancer. The genetic changes that characterise endometriosis are poorly understood; however, the mechanistic target of rapamycin (mTOR) pathway is involved. In this study, we investigated the expression of key mTOR components in endometriosis and the effects of rapalogues using an endometrioid ovarian carcinoma cell line (MDAH 2774) as an in vitro model. Gene expression of mTOR, DEPTOR, Rictor and Raptor was assessed by qPCR in 24 endometriosis patients and in silico in ovarian cancer patients. Furthermore, the effects of Rapamycin, Everolimus, Deforolimus, Temsirolimus, Resveratrol, and BEZ235 (Dactolisib, a dual kinase inhibitor) on mTOR signalling components was assessed. mTOR showed a significant increase in the expression in endometriosis and ovarian endometrioid adenocarcinoma patients compared to non‑affected controls. DEPTOR, an inhibitor of mTOR, was downregulated in the advanced stages of ovarian cancer (III and IV) compared to earlier stages (I and II). Treatment of MDAH‑2774 cells with the mTOR inhibitors resulted in the significant upregulation of DEPTOR mRNA, whereas treatment with rapamycin and BEZ‑235 (100 nM) resulted in downregulation of the mTOR protein expression after 48 h of treatment. None of the treatments resulted in translocation of mTOR from cytoplasm to nucleus. Upregulation of DEPTOR is a positive prognostic marker in ovarian cancer and is increased in response to mTOR pathway inhibition suggesting that it functions as a tumour suppressor gene in endometrioid ovarian carcinoma. Collectively, our data suggest the mTOR pathway as a potential connection between endometriosis and ovarian cancer and may be a potential target in the treatment of both conditions.

Bean GR, Krings G, Otis CN, et al.
CRTC1-MAML2 fusion in mucoepidermoid carcinoma of the breast.
Histopathology. 2019; 74(3):463-473 [PubMed] Related Publications
AIMS: Mucoepidermoid carcinomas (MEC) are the most common malignant neoplasms of salivary glands, but are uncommon in other sites. Salivary gland MEC are most frequently associated with CRTC1-MAML2 translocations. Exceedingly rare MEC of the breast demonstrate a basal-like and often triple (oestrogen and progesterone receptor, HER2)-negative immunophenotype, with a single case previously reported to show MAML2 rearrangement, although the fusion partner was not known. Comprehensive genomic studies of breast MEC are lacking. In this study, we analysed the immunophenotype and molecular landscape of two breast MEC to elucidate the pathogenesis of these rare tumours.
METHODS AND RESULTS: Two breast MEC were subjected to capture-based next-generation DNA sequencing of 479 cancer-related genes. The presence of the CRTC1-MAML2 fusion transcript was interrogated by reverse transcriptase-polymerase chain reaction. In addition, the immunoprofiles of breast MEC were compared to salivary gland MEC. Both breast MEC harboured CRTC1-MAML2 fusions. In contrast to most triple-negative breast carcinomas of no special type, the mutational burden of MEC was very low, with one case demonstrating only an inactivating SETD2 mutation, and the other harbouring no somatic variants in genes on the panel. No copy number alterations were identified. The immunoprofiles of breast and salivary gland MEC were overlapping, but not identical.
CONCLUSIONS: The findings highlight MEC as a breast cancer subtype more closely related to its salivary gland counterpart than to basal-like/triple-negative breast cancers of no special type.

Harachi M, Masui K, Okamura Y, et al.
mTOR Complexes as a Nutrient Sensor for Driving Cancer Progression.
Int J Mol Sci. 2018; 19(10) [PubMed] Article available free on PMC after 15/02/2020 Related Publications
Recent advancement in the field of molecular cancer research has clearly revealed that abnormality of oncogenes or tumor suppressor genes causes tumor progression thorough the promotion of intracellular metabolism. Metabolic reprogramming is one of the strategies for cancer cells to ensure their survival by enabling cancer cells to obtain the macromolecular precursors and energy needed for the rapid growth. However, an orchestration of appropriate metabolic reactions for the cancer cell survival requires the precise mechanism to sense and harness the nutrient in the microenvironment. Mammalian/mechanistic target of rapamycin (mTOR) complexes are known downstream effectors of many cancer-causing mutations, which are thought to regulate cancer cell survival and growth. Recent studies demonstrate the intriguing role of mTOR to achieve the feat through metabolic reprogramming in cancer. Importantly, not only mTORC1, a well-known regulator of metabolism both in normal and cancer cell, but mTORC2, an essential partner of mTORC1 downstream of growth factor receptor signaling, controls cooperatively specific metabolism, which nominates them as an essential regulator of cancer metabolism as well as a promising candidate to garner and convey the nutrient information from the surrounding environment. In this article, we depict the recent findings on the role of mTOR complexes in cancer as a master regulator of cancer metabolism and a potential sensor of nutrients, especially focusing on glucose and amino acid sensing in cancer. Novel and detailed molecular mechanisms that amino acids activate mTOR complexes signaling have been identified. We would also like to mention the intricate crosstalk between glucose and amino acid metabolism that ensures the survival of cancer cells, but at the same time it could be exploitable for the novel intervention to target the metabolic vulnerabilities of cancer cells.

He R, Yin Y, Yin W, et al.
Prevention of pancreatic acinar cell carcinoma by Roux-en-Y Gastric Bypass Surgery.
Nat Commun. 2018; 9(1):4183 [PubMed] Article available free on PMC after 15/02/2020 Related Publications
Roux-en-Y Gastric Bypass Surgery (RYGB) prevents the occurrence of pancreatic cell acinar carcinoma (ACC) in male and female Ngn3-Tsc1-/- mice. Ngn3 directed Cre deletion of Tsc1 gene induced the development of pancreatic ACC. The transgenic mice with sham surgery demonstrated a cancer incidence of 96.7 ± 3.35% and survival rate of 67.0 ± 1.4% at the age of 300 days. Metastasis to liver and kidney was observed in 69.7 ± 9.7% and 44.3 ± 8.01% of these animals, respectively. All animals with RYGB performed at the age of 16 weeks survived free of pancreatic ACC up to the age of 300 days. RYGB significantly attenuated the activation of mTORC1 signaling and inhibition of tumor suppressor genes: p21, p27, and p53 in pancreatic ACC. Our studies demonstrate that bariatric surgery may limit the occurrence and growth of pancreatic ACC through the suppression of mTORC1 signaling in pancreas. RYGB shows promise for intervention of both metabolic dysfunction and organ cancer.

Lam HC, Siroky BJ, Henske EP
Renal disease in tuberous sclerosis complex: pathogenesis and therapy.
Nat Rev Nephrol. 2018; 14(11):704-716 [PubMed] Related Publications
Tuberous sclerosis complex (TSC) is an autosomal dominant disease characterized by hamartomatous tumours of the brain, heart, skin, lung and kidney. Patients with TSC show a diverse range of neurological features (including seizures, cognitive disability and autism) and renal manifestations (including angiomyolipomas, epithelial cysts and renal cell carcinoma (RCC)). TSC is caused by inactivating mutations in TSC1 and TSC2, which encode hamartin and tuberin, respectively. These two proteins form a complex that negatively regulates mechanistic target of rapamycin complex 1 (mTORC1), a master regulator of cellular growth and metabolism. In clinical trials, allosteric inhibitors of mTORC1 decrease angiomyolipoma size, but the tumours regrow after treatment cessation. Therefore, the development of strategies to eliminate rather than suppress angiomyolipomas remains a high priority. This Review describes important advances in the TSC field and highlights several remaining critical knowledge gaps: the factors that promote aggressive behaviour by a subset of TSC-associated RCCs; the molecular mechanisms underlying early-onset cystogenesis in TSC2-PKD1 contiguous gene deletion syndrome; the effect of early, long-term mTORC1 inhibition on the development of TSC renal disease; and the identification of the cell or cells of origin of angiomyolipomas.

Blair JD, Hockemeyer D, Bateup HS
Genetically engineered human cortical spheroid models of tuberous sclerosis.
Nat Med. 2018; 24(10):1568-1578 [PubMed] Article available free on PMC after 15/02/2020 Related Publications
Tuberous sclerosis complex (TSC) is a multisystem developmental disorder caused by mutations in the TSC1 or TSC2 genes, whose protein products are negative regulators of mechanistic target of rapamycin complex 1 signaling. Hallmark pathologies of TSC are cortical tubers-regions of dysmorphic, disorganized neurons and glia in the cortex that are linked to epileptogenesis. To determine the developmental origin of tuber cells, we established human cellular models of TSC by CRISPR-Cas9-mediated gene editing of TSC1 or TSC2 in human pluripotent stem cells (hPSCs). Using heterozygous TSC2 hPSCs with a conditional mutation in the functional allele, we show that mosaic biallelic inactivation during neural progenitor expansion is necessary for the formation of dysplastic cells and increased glia production in three-dimensional cortical spheroids. Our findings provide support for the second-hit model of cortical tuber formation and suggest that variable developmental timing of somatic mutations could contribute to the heterogeneity in the neurological presentation of TSC.

Du H, Dreier JR, Zarei M, et al.
A novel mouse model of hemangiopericytoma due to loss of Tsc2.
Hum Mol Genet. 2018; 27(24):4169-4175 [PubMed] Article available free on PMC after 15/12/2019 Related Publications
Hemangiopericytoma (HPC) is a rare vascular tumor, which is thought to originate from pericytes. However, no direct evidence for the cell of origin has been found, and the mechanism of HPC tumorigenesis is poorly understood. Here we report that loss of the tumor suppressor gene Tsc2 in pericytes using a FoxD1 promoter driven cre allele (Foxd1tm1(GFP/cre) Amc, FoxD1GC) leads to the formation of HPC in multiple sites. Tsc2ffFoxD1GC mice had stunted growth with seizures and tail and hind limb tremor with a median survival of 110 days. They also showed recombination in brain, spinal cord, tongue, liver, intestine and skeletal muscle. Distinctive perivascular tumors consisting of cells with oval nuclei and scant cytoplasm were identified in multiple sites in all Tsc2ffFoxD1GC mice. Immunohistochemistry staining showed a high expression of phospho-S6-S240/244, a hallmark of activated mTORC1, as well as pericyte markers NG2 and vimentin in these tumors. In summary, we demonstrate that loss of Tsc2 in pericytes generates HPC, the first mouse model of HPC reported.

Boyle KA, Van Wickle J, Hill RB, et al.
Mitochondria-targeted drugs stimulate mitophagy and abrogate colon cancer cell proliferation.
J Biol Chem. 2018; 293(38):14891-14904 [PubMed] Article available free on PMC after 21/09/2019 Related Publications
Mutations in the KRAS proto-oncogene are present in 50% of all colorectal cancers and are increasingly associated with chemotherapeutic resistance to frontline biologic drugs. Accumulating evidence indicates key roles for overactive KRAS mutations in the metabolic reprogramming from oxidative phosphorylation to aerobic glycolysis in cancer cells. Here, we sought to exploit the more negative membrane potential of cancer cell mitochondria as an untapped avenue for interfering with energy metabolism in KRAS variant-containing and KRAS WT colorectal cancer cells. Mitochondrial function, intracellular ATP levels, cellular uptake, energy sensor signaling, and functional effects on cancer cell proliferation were assayed. 3-Carboxyl proxyl nitroxide (Mito-CP) and Mito-Metformin, two mitochondria-targeted compounds, depleted intracellular ATP levels and persistently inhibited ATP-linked oxygen consumption in both KRAS WT and KRAS variant-containing colon cancer cells and had only limited effects on nontransformed intestinal epithelial cells. These anti-proliferative effects reflected the activation of AMP-activated protein kinase (AMPK) and the phosphorylation-mediated suppression of the mTOR target ribosomal protein S6 kinase B1 (RPS6KB1 or p70S6K). Moreover, Mito-CP and Mito-Metformin released Unc-51-like autophagy-activating kinase 1 (ULK1) from mTOR-mediated inhibition, affected mitochondrial morphology, and decreased mitochondrial membrane potential, all indicators of mitophagy. Pharmacological inhibition of the AMPK signaling cascade mitigated the anti-proliferative effects of Mito-CP and Mito-Metformin. This is the first demonstration that drugs selectively targeting mitochondria induce mitophagy in cancer cells. Targeting bioenergetic metabolism with mitochondria-targeted drugs to stimulate mitophagy provides an attractive approach for therapeutic intervention in KRAS WT and overactive mutant-expressing colon cancer.

Bothwell PJ, Kron CD, Wittke EF, et al.
Targeted Suppression and Knockout of ASCT2 or LAT1 in Epithelial and Mesenchymal Human Liver Cancer Cells Fail to Inhibit Growth.
Int J Mol Sci. 2018; 19(7) [PubMed] Article available free on PMC after 21/09/2019 Related Publications
Amino acid transporters alanine-serine-cysteine transporter 2 (ASCT2) and L-Type Amino Acid Transporter 1 (LAT1) are coordinately enhanced in human cancers where among other roles, they are thought to drive mechanistic target-of-rapamycin (mTOR) growth signaling. To assess ASCT2 and LAT1 as therapeutic targets, nine unique short hairpin RNA (shRNA) vectors were used to stably suppress transporter expression in human epithelial (Hep3B) and mesenchymal (SK-Hep1) hepatocellular carcinoma (HCC) cell lines. In addition, six unique CRISPR-Cas9 vectors were used to edit the ASCT2 (

Xie Y, Li B, Bu W, et al.
Dihydrocelastrol exerts potent antitumor activity in mantle cell lymphoma cells via dual inhibition of mTORC1 and mTORC2.
Int J Oncol. 2018; 53(2):823-834 [PubMed] Related Publications
Mantle cell lymphoma (MCL) is a distinct and highly aggressive subtype of B-cell non-Hodgkin lymphoma. Dihydrocelastrol (DHCE) is a dihydro-analog of celastrol, which is isolated from the traditional Chinese medicinal plant Tripterygium wilfordii. The present study aimed to investigate the effects of DHCE treatment on MCL cells, and to determine the mechanism underlying its potent antitumor activity in vitro and in vivo using the Cell Counting kit-8 assay, clonogenic assay, apoptosis assay, cell cycle analysis, immunofluorescence staining, western blotting and tumor xenograft models. The results demonstrated that DHCE treatment exerted minimal cytotoxic effects on normal cells, but markedly suppressed MCL cell proliferation by inducing G0/G1 phase cell cycle arrest, and inhibited MCL cell viability by stimulating apoptosis via extrinsic and intrinsic pathways. In addition, the results revealed that DHCE suppressed cell growth and proliferation by inhibiting mammalian target of rapamycin complex (mTORC)1-mediated phosphorylation of ribosomal protein S6 kinase and eukaryotic initiation factor 4E binding protein. Simultaneously, DHCE induced apoptosis and inhibited cell survival by suppressing mTORC2-mediated phosphorylation of protein kinase B and nuclear factor-κB activity. In addition to in vitro findings, DHCE treatment reduced the MCL tumor burden in a xenograft mouse model, without indications of toxicity. Furthermore, combined treatment with DHCE and bortezomib, a proteasome inhibitor, induced a synergistic cytotoxic effect on MCL cells. These findings indicated that DHCE may have the potential to serve as a novel therapeutic agent for the treatment of MCL through dually inhibiting mTORC1 and mTORC2.

Krencz I, Sebestyen A, Papay J, et al.
In situ analysis of mTORC1/2 and cellular metabolism-related proteins in human Lymphangioleiomyomatosis.
Hum Pathol. 2018; 79:199-207 [PubMed] Related Publications
Lymphangioleiomyomatosis (LAM) is a rare progressive cystic lung disease with features of a low-grade neoplasm. It is primarily caused by mutations in TSC1 or TSC2 genes. Sirolimus, an inhibitor of mTOR complex 1 (mTORC1), slows down disease progression in some, but not all patients. Hitherto, other potential therapeutic targets such as mTOR complex 2 (mTORC2) and various metabolic pathways have not been investigated in human LAM tissues. The aim of this study was to assess activities of mTORC1, mTORC2 and various metabolic pathways in human LAM tissues through analysis of protein expression. Immunohistochemical analysis of p-S6 (mTORC1 downstream protein), Rictor (mTORC2 scaffold protein) as well as GLUT1, GAPDH, ATPB, GLS, MCT1, ACSS2 and CPT1A (metabolic pathway markers) were performed on lung tissue from 11 patients with sporadic LAM. Immunoreactivity was assessed in LAM cells with bronchial smooth muscle cells as controls. Expression of p-S6, Rictor, GAPDH, GLS, MCT1, ACSS2 and CPT1A was significantly higher in LAM cells than in bronchial smooth muscle cells (P<.01). No significant differences were found between LAM cells and normal bronchial smooth muscle cells in GLUT1 and ATPB expression. The results are uniquely derived from human tissue and indicate that, in addition to mTORC1, mTORC2 may also play an important role in the pathobiology of LAM. Furthermore, glutaminolysis, acetate utilization and fatty acid β-oxidation appear to be the preferred bioenergetic pathways in LAM cells. mTORC2 and these preferred bioenergetic pathways appear worthy of further study as they may represent possible therapeutic targets in the treatment of LAM.

Ribas R, Pancholi S, Rani A, et al.
Targeting tumour re-wiring by triple blockade of mTORC1, epidermal growth factor, and oestrogen receptor signalling pathways in endocrine-resistant breast cancer.
Breast Cancer Res. 2018; 20(1):44 [PubMed] Article available free on PMC after 21/09/2019 Related Publications
BACKGROUND: Endocrine therapies are the mainstay of treatment for oestrogen receptor (ER)-positive (ER
METHODS: A panel of ER
RESULTS: Here, we show RAD001 and neratinib (pan-ERBB inhibitor) caused a concentration-dependent decrease in proliferation, irrespective of the ESR1 mutation status. The combination of either agent with endocrine therapy further reduced proliferation but the maximum effect was observed with a triple combination of RAD001, neratinib, and endocrine therapy. In the absence of oestrogen, RAD001 caused a reduction in ER-mediated transcription in the majority of the cell lines, which associated with a decrease in recruitment of ER to an oestrogen-response element on the TFF1 promoter. Contrastingly, neratinib increased both ER-mediated transactivation and ER recruitment, an effect reduced by the addition of RAD001. In-vivo analysis of an LTED model showed the triple combination of RAD001, neratinib, and fulvestrant was most effective at reducing tumour volume. Gene set enrichment analysis revealed that the addition of neratinib negated the epidermal growth factor (EGF)/EGF receptor feedback loops associated with RAD001.
CONCLUSIONS: Our data support the combination of therapies targeting ERBB2/3 and mTORC1 signalling, together with fulvestrant, in patients who relapse on endocrine therapy and retain a functional ER.

Roy S, Banerjee S, Chakraborty T
Vanadium quercetin complex attenuates mammary cancer by regulating the P53, Akt/mTOR pathway and downregulates cellular proliferation correlated with increased apoptotic events.
Biometals. 2018; 31(4):647-671 [PubMed] Related Publications
Flavonoid metal ion complexes have been deliberated in recent years and are considered as a new class of medicinal agents with enhanced therapeutic activity and low toxicity. Our study deals with chemotherapeutic effects of vanadium, when coordinated with the flavonoid quercetin on a defined model of chemically induced rat mammary carcinogenesis in vivo and on human breast cancer cell line MCF-7 in vitro. The characterization of the complex was achieved through UV-Visible, IR, and Mass spectra and antioxidant activity was assessed by DPPH, FRAP and ABTS methods. In vitro studies established that the complex upregulated the expressions of p53, Caspase 3 and 9, whereas down regulating Akt, mTOR and VEGF expressions and also induced apoptosis and DNA fragmentation in a dose dependent manner. Acute and Sub-acute toxicity was performed to determine safe doses. 7,12-Dimethylbenz(α)anthracene (0.5 mg/100 g body weight) was used for induction of breast cancer in female Sprague-Dawley rats via single tail vein injection. The histopathological analysis after 24 weeks of carcinogenesis study depicted substantial repair of hyperplastic lesions. TUNEL assay showed an increase in apoptotic index (0.14 ± 0.03; 0.15 ± 0.01) in vanadium-quercetin treated groups as compared to the carcinogen control (0.02 ± 0.01) along with upregulation of Bcl-2 and downregulation of Bax and p53. Immunohistochemical analysis also exhibited decrease in cell proliferation in the vanadium-quercetin treated groups (11.3 ± 0.12; 11.8 ± 0.10). Thus, results from both in vivo and in vitro studies revealed that vanadium-quercetin complex could be a potential candidate for development of approved drug for breast cancer in the near future.

Sundaramoorthy S, Devanand P, Ryu MS, et al.
TIS21
J Cancer Res Clin Oncol. 2018; 144(8):1445-1462 [PubMed] Related Publications
PURPOSE: It has been reported that PI3K/AKT pathway is altered in various cancers and AKT isoforms specifically regulate cell growth and metastasis of cancer cells; AKT1, but not AKT2, reduces invasion of cancer cells but maintains cancer growth. We propose here a novel mechanism of the tumor suppresser, TIS21
METHODS: Transduction of adenovirus carrying TIS21
RESULTS: We observed that TIS21
CONCLUSIONS: TIS21

Chen J, Ou Y, Yang Y, et al.
KLHL22 activates amino-acid-dependent mTORC1 signalling to promote tumorigenesis and ageing.
Nature. 2018; 557(7706):585-589 [PubMed] Related Publications
The mechanistic target of rapamycin complex 1 (mTORC1) is a master regulator of cell growth that responds to a diverse set of environmental cues, including amino acids

Tavares C, Eloy C, Melo M, et al.
mTOR Pathway in Papillary Thyroid Carcinoma: Different Contributions of mTORC1 and mTORC2 Complexes for Tumor Behavior and
Int J Mol Sci. 2018; 19(5) [PubMed] Article available free on PMC after 21/09/2019 Related Publications
The mammalian target of rapamycin (mTOR) pathway is overactivated in thyroid cancer (TC). We previously demonstrated that phospho-mTOR expression is associated with tumor aggressiveness, therapy resistance, and lower mRNA expression of

Zhang J, Chen J, Ma T, et al.
Genetic variants of FOXP1 and FOXF1 are associated with the susceptibility of oesophageal adenocarcinoma in Chinese population.
J Genet. 2018; 97(1):213-218 [PubMed] Related Publications
This study aimed to investigate whether the genetic variants of CRTC1, BARX1, FOXP1 and FOXF1 are associated with the development of oesophageal adenocarcinoma (OA) in Chinese population. A total of 744 OA patients and 1138 controls were included in this study. Here we genotyped four SNPs, rs10419226 of CRTC1, rs11789015 of BARX1, rs2687201 of FOXP1 and rs3111601 of FOXF1. The chi-square test was used to compare the genotype and allele frequencies between the patients and controls. The student's t-test was used to compare FOXP1 expression in the tumour and the adjacent normal tissues. The relationship between genotypes of rs2687201 and FOXP1 expression was investigated by one-way analysis of variance test. Patients were found to have significantly higher frequency of allele A of rs2687201 and allele C of rs3111601 when compared with the controls (49.2 vs 43.4%, P = 0.0008 for rs2687201; 29.1 vs 24.0%, P = 0.0003 for rs3111601). There was a significantly higher expression level of FOXP1 in the tumour than in the adjacent normal tissue (0.0052 ± 0.0021 vs 0.0027 ± 0.0018, P < 0.001). Patients with genotype AA were found to have remarkably higher FOXP1 expression in the tumour than those with genotype CC (P = 0.01). To conclude, the varients of FOXP1 and FOXF1 genes are functionally associated with OA in Chinese population.With the identification of more susceptible loci, the combined effect of these markers may be helpful for the surveillance of OA.

Zhao Z, Li J, Tan F, et al.
mTOR up-regulation of BEX4 promotes lung adenocarcinoma cell proliferation by potentiating OCT4.
Biochem Biophys Res Commun. 2018; 500(2):302-309 [PubMed] Related Publications
Previously, BEX family members have been reported to participate in cancer development. However, little is known about the role of BEX4 in lung adenocarcinoma (LAC). Here, we found that BEX4 was over-expressed in LAC tissues compared with adjacent tissues. LAC tissues from metastatic patients exhibited higher expression of BEX4 comparing to those from non-metastatic ones. In vitro, BEX4 ectopic expression accelerated the proliferation of both A549 and H1975 cells. By contrast, knockdown of BEX4 suppressed the proliferation of A549 and H1975 cells. BEX4 positively regulated the expression of OCT4, silencing of which reduced the proliferation of A549 and H1975 cells with over-expressed BEX4. Additionally, mTOR activation, which is frequently observed in LAC, potentiated BEX4 depending on mTORC1 but not mTORC2. BEX4 abundance dictated the sensitivity of A549 and H1975 cells to rapamycin treatment. Our findings reveal that BEX4 is an oncogene in LAC and may contribute to the hyper-active mTOR-induced LAC development.

Rudat S, Pfaus A, Cheng YY, et al.
RET-mediated autophagy suppression as targetable co-dependence in acute myeloid leukemia.
Leukemia. 2018; 32(10):2189-2202 [PubMed] Related Publications
Many cases of AML are associated with mutational activation of receptor tyrosine kinases (RTKs) such as FLT3. However, RTK inhibitors have limited clinical efficacy as single agents, indicating that AML is driven by concomitant activation of different signaling molecules. We used a functional genomic approach to identify RET, encoding an RTK, as an essential gene in multiple subtypes of AML, and observed that AML cells show activation of RET signaling via ARTN/GFRA3 and NRTN/GFRA2 ligand/co-receptor complexes. Interrogation of downstream pathways identified mTORC1-mediated suppression of autophagy and subsequent stabilization of leukemogenic drivers such as mutant FLT3 as important RET effectors. Accordingly, genetic or pharmacologic RET inhibition impaired the growth of FLT3-dependent AML cell lines and was accompanied by upregulation of autophagy and FLT3 depletion. RET dependence was also evident in mouse models of AML and primary AML patient samples, and transcriptome and immunohistochemistry analyses identified elevated RET mRNA levels and co-expression of RET and FLT3 proteins in a substantial proportion of AML patients. Our results indicate that RET-mTORC1 signaling promotes AML through autophagy suppression, suggesting that targeting RET or, more broadly, depletion of leukemogenic drivers via autophagy induction provides a therapeutic opportunity in a relevant subset of AML patients.

McKenna J, Kapfhamer D, Kinchen JM, et al.
Metabolomic studies identify changes in transmethylation and polyamine metabolism in a brain-specific mouse model of tuberous sclerosis complex.
Hum Mol Genet. 2018; 27(12):2113-2124 [PubMed] Article available free on PMC after 21/09/2019 Related Publications
Tuberous sclerosis complex (TSC) is an autosomal dominant neurodevelopmental disorder and the quintessential disorder of mechanistic Target of Rapamycin Complex 1 (mTORC1) dysregulation. Loss of either causative gene, TSC1 or TSC2, leads to constitutive mTORC1 kinase activation and a pathologically anabolic state of macromolecular biosynthesis. Little is known about the organ-specific metabolic reprogramming that occurs in TSC-affected organs. Using a mouse model of TSC in which Tsc2 is disrupted in radial glial precursors and their neuronal and glial descendants, we performed an unbiased metabolomic analysis of hippocampi to identify Tsc2-dependent metabolic changes. Significant metabolic reprogramming was found in well-established pathways associated with mTORC1 activation, including redox homeostasis, glutamine/tricarboxylic acid cycle, pentose and nucleotide metabolism. Changes in two novel pathways were identified: transmethylation and polyamine metabolism. Changes in transmethylation included reduced methionine, cystathionine, S-adenosylmethionine (SAM-the major methyl donor), reduced SAM/S-adenosylhomocysteine ratio (cellular methylation potential), and elevated betaine, an alternative methyl donor. These changes were associated with alterations in SAM-dependent methylation pathways and expression of the enzymes methionine adenosyltransferase 2A and cystathionine beta synthase. We also found increased levels of the polyamine putrescine due to increased activity of ornithine decarboxylase, the rate-determining enzyme in polyamine synthesis. Treatment of Tsc2+/- mice with the ornithine decarboxylase inhibitor α-difluoromethylornithine, to reduce putrescine synthesis dose-dependently reduced hippocampal astrogliosis. These data establish roles for SAM-dependent methylation reactions and polyamine metabolism in TSC neuropathology. Importantly, both pathways are amenable to nutritional or pharmacologic therapy.

Zhang C, Zhang CD, Ma MH, Dai DQ
Three-microRNA signature identified by bioinformatics analysis predicts prognosis of gastric cancer patients.
World J Gastroenterol. 2018; 24(11):1206-1215 [PubMed] Article available free on PMC after 21/09/2019 Related Publications
AIM: To identify multiple microRNAs (miRNAs) for predicting the prognosis of gastric cancer (GC) patients by bioinformatics analysis.
METHODS: The original microarray dataset GSE93415, which included 20 GC and 20 tumor adjacent normal gastric mucosal tissues, was downloaded from the Gene Expression Omnibus database and used for screening differentially expressed miRNAs (DEMs). The cut-off criteria were
RESULTS: A total of 110 DEMs including 19 up-regulated and 91 down-regulated miRNAs were identified between 20 pairs of GC and tumor adjacent normal tissues, and the Kaplan-Meier survival analysis found that a three-miRNA signature (miR-145-3p, miR-125b-5p, and miR-99a-5p) had an obvious correlation with the survival of GC patients. Furthermore, univariate and multivariate Cox regression analyses indicated that the three-miRNA signature could be a significant prognostic marker in GC patients. The common target genes of the three miRNAs are added up to 108 and used for Gene Functional Enrichment analysis. Biological Process and Molecular Function analyses showed that the target genes are involved in cell recognition, gene silencing and nucleic acid binding, transcription factor activity, and transmembrane receptor activity. Cellular Component analysis revealed that the genes are portion of nucleus, chromatin silencing complex, and TORC1/2 complex. Biological Pathway analysis indicated that the genes participate in several cancer-related pathways, such as the focal adhesion, PI3K, and mTOR signaling pathways.
CONCLUSION: This study justified that a three-miRNA signature could play a role in predicting the survival of GC patients.

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