Hsa_circ_0007059 sponges miR-421 to repress cell growth and stemness in hepatocellular carcinoma by the PTEN-AKT/mTOR pathway.

BACKGROUND: Hepatocellular carcinoma (HCC) is a substantial health concern worldwide. Increasing studies have suggested that circle RNAs (circRNAs) function as new regulators in HCC progression. The present work explored the role of hsa_circ_0007059 (circ_0007059) in the developing process of hepatocarcinogenesis. METHODS: The circ_0007059 level in HCC was determined by reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) and northern blot. Its biological role in HCC cells was assessed using 3-(4,5-Dimethylthiazol-2-yl)- 2,5-diphenyltetrazolium bromide (MTT), colony formation, flow cytometry, Transwell, sphere formation and western blotting analyses. Bioinformatics analysis, luciferase reporter, and RNA immunoprecipitation (RIP) assays were used to test the regulatory mechanisms of circ_0007059. RESULTS: Our results revealed that circ_0007059 expression was downregulated in HCC samples and cells. Moreover, circ_0007059 overexpression inhibited HCC cell proliferation, migration, invasion, and stem cell-like property, and strengthened cell apoptosis. In mechanism, circ_0007059 suppressed AKT/mTOR pathway by positively regulating phosphatase and tensin homolog (PTEN) expression. Additionally, circ_0007059 acted as a positive regulator of PTEN through controlling the availability of miR-421. Rescue assays demonstrated that PTEN knockdown or SC79 (AKT agonist) eliminated the effect of circ_0007059 on HCC cell phenotypes. CONCLUSION: Circ_0007059 sponges miR-421 to inhibit oncogenic cellular process in HCC by mediating the PTEN-AKT/mTOR pathway.

Down-Regulation of Casein Kinase 1α Contributes to Endometriosis through Phosphatase and Tensin Homolog/Autophagy-Related 7-Mediated Autophagy.

The present study aimed to explore the roles of casein kinase 1α (CK1α) in endometriosis and its underlying mechanisms. Endometrial specimen were collected from the patients and healthy volunteers. The expression patterns of CK1α, phosphatase and tensin homolog (PTEN), and autophagy-related proteins were determined using immunohistochemistry staining, Western blot analysis, and quantitative RT-PCR. Besides, the CK1α-overexpressing cells and PTEN knockdown cells were constructed in the endometrial stromal cells isolated from endometriosis patients. In addition, the cells were transfected with pcDNA3.1-CK1α or pcDNA3.1-CK1α plus siRNA- PTEN. The expressions of CK1α, PTEN, and autophagy-related proteins were determined using Western blot and quantitative RT-PCR. The expressions of CK1α and autophagy-related 7 (Atg7) were significantly decreased in the ectopic endometrium compared with the eutopic endometrium. Spearman rank correlation analysis revealed positive correlations between CK1α and PTEN, CK1α and Atg7, and PTEN and Atg7. In addition, CK1α, PTEN, and autophagy-related proteins were down-regulated in ectopic endometrium. Interestingly, overexpression of CK1α significantly increased the expressions of autophagy-related proteins, whereas the protein expression of autophagy-related proteins was decreased with PTEN knock-down. CK1α regulated PTEN/Atg7-mediated autophagy in endometriosis.

Novel Mouse Models of Bladder Cancer Identify a Prognostic Signature Associated with Risk of Disease Progression.

To study the progression of bladder cancer from non-muscle-invasive to muscle-invasive disease, we have developed a novel toolkit that uses complementary approaches to achieve gene recombination in specific cell populations in the bladder urothelium in vivo, thereby allowing us to generate a new series of genetically engineered mouse models (GEMM) of bladder cancer. One method is based on the delivery of adenoviruses that express Cre recombinase in selected cell types in the urothelium, and a second uses transgenic drivers in which activation of inducible Cre alleles can be limited to the bladder urothelium by intravesicular delivery of tamoxifen. Using both approaches, targeted deletion of the Pten and p53 tumor suppressor genes specifically in basal urothelial cells gave rise to muscle-invasive bladder tumors. Furthermore, preinvasive lesions arising in basal cells displayed upregulation of molecular pathways related to bladder tumorigenesis, including proinflammatory pathways. Cross-species analyses comparing a mouse gene signature of early bladder cancer with a human signature of bladder cancer progression identified a conserved 28-gene signature of early bladder cancer that is associated with poor prognosis for human bladder cancer and that outperforms comparable gene signatures. These findings demonstrate the relevance of these GEMMs for studying the biology of human bladder cancer and introduce a prognostic gene signature that may help to stratify patients at risk for progression to potentially lethal muscle-invasive disease. SIGNIFICANCE: Analyses of bladder cancer progression in a new series of genetically engineered mouse models has identified a gene signature of poor prognosis in human bladder cancer.

Sleeping Beauty Transposon Mutagenesis Identifies Genes Driving the Initiation and Metastasis of Uterine Leiomyosarcoma.

Uterine leiomyosarcoma (ULMS) is a malignancy, which arises from the uterine smooth muscle. Because of its rarity, aggressive nature, and extremely poor prognosis, the molecular mechanisms driving ULMS remain elusive. To identify candidate cancer genes (CCG) driving ULMS, we conducted an in vivo Sleeping Beauty (SB) transposon mutagenesis screen in uterine myometrium-specific, PTEN knockout, KRAS mutant (PTEN KO/KRAS) mice. ULMS quickly developed in SB PTEN KO/KRAS mice, but not in PTEN KO/KRAS mice, demonstrating the critical importance of SB mutagenesis for driving ULMS in this model. Subsequent sequencing of SB insertion sites in these tumors identified 19 ULMS CCGs that were significantly enriched in known cancer genes. Among them, Zfp217 and Sfmbt2 functioned at early stages of tumor initiation and appeared to be oncogenes. Expression of ZNF217, the human homolog of ZFP217, was shown to be elevated in human ULMS compared with paired normal uterine smooth muscle, where it negatively correlated with patient prognosis. Inhibition of ZNF217 suppressed, whereas overexpression induced, proliferation, survival, migration, and stemness of human ULMS. In a second ex vivo ULMS SB metastasis screen, three CCGs were identified that may drive ULMS metastasis to the lung. One of these CCGs, Nrd1 (NRDC in humans), showed stronger expression in human metastatic tumors compared with primary ULMS and negatively associated with patient survival. NRDC knockdown impaired migration and adhesion without affecting cell proliferation, whereas overexpression had the opposite effect. Together, these results reveal novel mechanism driving ULMS tumorigenesis and metastasis and identify ZNF217 and NRDC as potential targets for ULMS therapy. SIGNIFICANCE: An in vivo Sleeping Beauty transposon mutagenesis screen identifies candidate cancer genes that drive initiation and progression of uterine leiomyosarcoma and may serve as therapeutic targets.

Diagnosis and management of an endometrial cancer patient with Cowden syndrome.

Somatic PTEN alterations are common in endometrial carcinoma (EC), but in rare cases PTEN mutations are associated with inherited syndromes. Here, we present a case of Cowden syndrome-associated EC. We discuss clinical, pathologic and molecular features of her tumor and PTEN-mutated EC, inherited syndromes predisposing to EC and PTEN-targeted therapies.

Macrophage-Derived Cholesterol Contributes to Therapeutic Resistance in Prostate Cancer.

Castration-resistant prostate cancer (CRPC) is a lethal stage of disease in which androgen receptor (AR) signaling is persistent despite androgen deprivation therapy (ADT). Most studies have focused on investigating cell-autonomous alterations in CRPC, while the contributions of the tumor microenvironment are less well understood. Here we sought to determine the role of tumor-associated macrophages in CRPC, based upon their role in cancer progression and therapeutic resistance. In a syngeneic model that reflected the mutational landscape of CRPC, macrophage depletion resulted in a reduced transcriptional signature for steroid and bile acid synthesis, indicating potential perturbation of cholesterol metabolism. As cholesterol is the precursor of the five major types of steroid hormones, we hypothesized that macrophages were regulating androgen biosynthesis within the prostate tumor microenvironment. Macrophage depletion reduced androgen levels within prostate tumors and restricted AR nuclear localization in vitro and in vivo. Macrophages were also cholesterol-rich and were able to transfer cholesterol to tumor cells in vitro. AR nuclear translocation was inhibited by activation of liver X receptor (LXR)-ß, the master regulator of cholesterol homeostasis. Consistent with these data, macrophage depletion extended survival during ADT and the presence of macrophages correlated with therapeutic resistance in patient-derived explants. Taken together, these findings support the therapeutic targeting of macrophages in CRPC. SIGNIFICANCE: These results suggest that macrophage-targeted therapies can be combined with androgen deprivation therapy to treat patients with prostate cancer by limiting cholesterol bioavailability and the production of intratumoral androgens.See related commentary by Al-Janabi and Lewis, p. 5399.

Modeling High-Grade Serous Ovarian Carcinoma Using a Combination of In Vivo Fallopian Tube Electroporation and CRISPR-Cas9-Mediated Genome Editing.

Ovarian cancer is the most lethal gynecologic cancer to date. High-grade serous ovarian carcinoma (HGSOC) accounts for most ovarian cancer cases, and it is most frequently diagnosed at advanced stages. Here, we developed a novel strategy to generate somatic ovarian cancer mouse models using a combination of in vivo electroporation and CRISPR-Cas9-mediated genome editing. Mutation of tumor suppressor genes associated with HGSOC in two different combinations (Brca1, Tp53, Pten with and without Lkb1) resulted in successfully generation of HGSOC, albeit with different latencies and pathophysiology. Implementing Cre lineage tracing in this system enabled visualization of peritoneal micrometastases in an immune-competent environment. In addition, these models displayed copy number alterations and phenotypes similar to human HGSOC. Because this strategy is flexible in selecting mutation combinations and targeting areas, it could prove highly useful for generating mouse models to advance the understanding and treatment of ovarian cancer. SIGNIFICANCE: This study unveils a new strategy to generate genetic mouse models of ovarian cancer with high flexibility in selecting mutation combinations and targeting areas.

Curcumin suppresses tumor growth of gemcitabine-resistant non-small cell lung cancer by regulating lncRNA-MEG3 and PTEN signaling

Background Lung cancer is one of the most aggressive malignancies and the efficacy of chemotherapy or concurrent chemoradiation is limited in clinical application. Curcumin has been reported to block cancer development by modulating multiple signaling pathways. However, whether curcumin can inhibit gemcitabine-resistant non-small cell lung cancer through regulation of lncRNA and the involved molecular mechanisms are rarely reported. Materials and methods MTT assay, clonogenic assay, apoptosis assay, qRT-PCR, Western blotting, immunohistochemistry, xenograft experiment were carried out in the present study. Results The results showed that curcumin suppressed gemcitabine-resistant non-small cell lung cancer cell proliferation and induced apoptosis. Curcumin upregulated the expression of lncRNA-MEG3 and PTEN, and MEG3 overexpression could increase the level of PTEN expression, while MEG3 knockdown decreased the level of PTEN expression in gemcitabine-resistant non-small cell lung cancer cells. Curcumin treatment failed to inhibit the proliferation and induce apoptosis in MEG3 knockdown or PTEN knockdown cells. Conclusions These findings show the antitumor activity of curcumin for potential clinical application in gemcitabine-resistant non-small cell lung cancer treatment (AU)

Targeting therapy-resistant lung cancer stem cells via disruption of the AKT/TSPYL5/PTEN positive-feedback loop.

Cancer stem cells (CSCs) are regarded as essential targets to overcome tumor progression and therapeutic resistance; however, practical targeting approaches are limited. Here, we identify testis-specific Y-like protein 5 (TSPYL5) as an upstream regulator of CSC-associated genes in non-small cell lung cancer cells, and suggest as a therapeutic target for CSC elimination. TSPYL5 elevation is driven by AKT-dependent TSPYL5 phosphorylation at threonine-120 and stabilization via inhibiting its ubiquitination. TSPYL5-pT120 also induces nuclear translocation and functions as a transcriptional activator of CSC-associated genes, ALDH1 and CD44. Also, nuclear TSPYL5 suppresses the transcription of PTEN, a negative regulator of PI3K signaling. TSPYL5-pT120 maintains persistent CSC-like characteristics via transcriptional activation of CSC-associated genes and a positive feedback loop consisting of AKT/TSPYL5/PTEN signaling pathway. Accordingly, elimination of TSPYL5 by inhibiting TSPYL5-pT120 can block aberrant AKT/TSPYL5/PTEN cyclic signaling and TSPYL5-mediated cancer stemness regulation. Our study suggests TSPYL5 be an effective target for therapy-resistant cancer.

Anti-androgen therapy induces transcriptomic reprogramming in metastatic castration-resistant prostate cancer in a murine model.

Despite recent development of next-generation androgen receptor (AR) antagonists, metastatic castration-resistant prostate cancer (CRPC) remains incurable and requires deeper understanding through studies in suitable animal models. Prostate-specific deletion of Pten and Smad4 in mice recapitulated the disease progression of human prostate adenocarcinoma, including metastasis to lymph nodes and lung. Moreover, Pten/Smad4 tumors fostered an immunosuppressive microenvironment dominated by myeloid-derived suppressor cells (MDSCs). However, the response of Pten/Smad4 tumors to androgen deprivation and anti-androgen therapies has not been described. Here, we report that the combination of surgical castration and enzalutamide treatment in Pten/Smad4 mice slowed down the tumor growth and prolonged the median survival of the mice for 8 weeks. Treatment-naïve and castration-resistant primary tumors exhibited comparable levels of immune infiltrations with the exception of reduced monocytic MDSCs in CRPC. RNA profiling of treatment-naïve and castration-resistant primary tumors revealed largely preserved transcriptome with modest expressional alterations of collagen-related and immune-related genes, among which CC chemokine receptor type 2 (Ccr2) downregulation and predicted negative activation in CRPC was consistent with reduced monocytic MDSC infiltration. Importantly, significant transcriptomic reprograming was observed in lung metastatic CRPC compared with primary CRPC and enriched for immune-related and coagulation-related pathways. At the individual gene level, we validated the expression changes of some of the most upregulated (Cd36, Bmp5, Bmp6, Etv5, Prex2, Ptprb, Egfl6, Itga8 and Cxcl12) and downregulated genes (Cxcl9 and Adamts5). Together, this study uncovers the inherent activity of Pten/Smad4 tumors to progress to CRPC and highlights potentially targetable transcriptomic signatures associated with CRPC metastasis.

Autophagy and PTEN in DNA damage-induced senescence.

The use of DNA-damaging agents such as radiotherapy and chemotherapy has been a mainstay treatment protocol for many cancers, including lung and prostate. Recently, FDA approval of inhibitors of DNA repair, and targeting innate immunity to enhance the efficacy of DNA-damaging agents have gained much attention. Yet, inherent or acquired resistance against DNA-damaging therapies persists as a fundamental drawback. While cancer eradication by causing cancer cell death through induction of apoptosis is the ultimate goal of anti-cancer treatments, autophagy and senescence are two major cellular responses induced by clinically tolerable doses of DNA-damaging therapies. Unlike apoptosis, autophagy and senescence can act as both pro-tumorigenic as well as tumor suppressive mechanisms. DNA damage-induced senescence is associated with a pro-inflammatory secretory phenotype, which contributes to reshaping the tumor- immune microenvironment. Moreover, PTEN (phosphatase and tensin homolog) is a tumor supressor deleted in many tumors, and has been implicated in both senescence and autophagy. This review presents an overview of the literature on the regulation and consequences of DNA damage- induced senescence in cancer cells, with a specific focus on autophagy and PTEN. Both autophagy and senescence occur concurrently in the same cells in response to DNA damaging agents. However, a deterministic relationship between these fundamental processes has been controversial. We present experimental evidence obtained with tumor cells, with a prime focus on two models of cancer, prostate and lung. A better understanding of mechanisms associated with DNA damage-induced cellular senescence is central to fully exploit the potential of DNA-damaging agents against cancer.

Circular RNA circ-PTEN elevates PTEN inhibiting the proliferation of non-small cell lung cancer cells.

Phosphatase and tensin homolog (PTEN) is a well-known tumor suppressor in various cancer types, including non-small cell lung cancer (NSCLC). Circular RNA (circRNA) has recently been proven to be strongly linked with cancer progression. Here, we aimed to investigate the biological relevance and clinical significance of circRNA derived from PTEN in NSCLC. We found that circ-PTEN (hsa_circ_0094342) was significantly decreased in NSCLC tissues and serum, which was attributed to the upregulation of RNA-binding protein DHX9. Low circ-PTEN was linked with malignant clinical features and poor outcome. Exogenous expression of circ-PTEN markedly inhibited NSCLC cell proliferation in vitro as well as retarded tumor growth in vivo. Circ-PTEN increased the expression of its host gene PTEN via acting as a sponge for miR-155 and miR-330-3p, leading to the inactivation of the carcinogenic PI3K/AKT signaling pathway. The xenograft tumor model also indicated the existence of circ-PTEN/miR-155/miR-330-3p/PTEN regulatory axis in vivo. Our data for the first time demonstrate that circ-PTEN functions as a tumor-inhibiting circRNA in NSCLC through post-transcriptionally regulating PTEN, hinting a promising diagnostic/prognostic biomarker as well as therapeutic target for NSCLC patients.

PTEN-mediated AKT/ß-catenin signaling enhances the proliferation and expansion of Lgr5+ hepatocytes.

Rationale: Compelling evidence suggests that Lgr5+ hepatocytes repair liver damage by promoting the regeneration of hepatocytes and ductal cells in the case of liver injury. The PTEN-mediated AKT/ß-catenin signaling plays a key role in the regulation of innate immune regulation in the liver. However, the signaling pathways that control Lgr5+ hepatocyte proliferation in the liver remain unclear. Methods: In order to assess the involvement of PTEN-mediated AKT/ß-catenin signaling in the expansion of Lgr5+ hepatocytes upon liver injuries, the Lgr5-CreER; Rosa-mTmG lineage tracing system was used to target Lgr5+ hepatocytes. Results: The tracing of Lgr5+ hepatocytes showed that PTEN deletion and ß-catenin activation significantly promoted the proliferation of Lgr5+ hepatocytes. In converse, the simultaneous inhibition of PTEN and ß-catenin limited Lgr5+ hepatocyte proliferation in the liver. Our findings provide an insight into understanding how PTEN-mediated AKT/ß-catenin signaling regulates the proliferation of Lgr5+ hepatocytes. Conclusion: The outcomes can improve the application potential of Lgr5+ hepatocytes in the treatment of liver injury diseases and provide a new treatment option for liver cancer.

TUBB3 is associated with PTEN, neuroendocrine differentiation, and castration resistance in prostate cancer.

BACKGROUND: Tubulin-ß3 encoded by the Tubulin-ß3 (TUBB3) gene is a microtubule protein. Previous studies have shown that TUBB3 expression is upregulated in castration-resistant prostate cancer (CaP) and is involved in taxane resistance. However, the biological mechanism of TUBB3 involvement in the progression to castration-resistant CaP is not fully elucidated. This study aimed to analyze the expression and function of TUBB3 in localized and metastatic CaP. METHODS: TUBB3 expression was determined using immunohistochemistry in localized and metastatic CaP. We also investigated the association between TUBB3, phosphatase and tensin homolog (PTEN), and neuroendocrine differentiation and examined the involvement of TUBB3 in new antiandrogen drugs (enzalutamide and apalutamide) resistance in metastatic CaP. RESULTS: In 155 cases of localized CaP, immunohistochemistry showed that 5 (3.2%) of the CaP cases were positive for tubulin-ß3. Kaplan-Meier analysis showed that high expression of tubulin-ß3 was associated with poor prostate-specific antigen recurrence-free survival after radical prostatectomy. In 57 cases of metastatic CaP, immunohistochemistry showed that 14 (25%) cases were positive for tubulin-ß3. Tubulin-ß3 expression was higher in metastatic CaP than in localized CaP. High tubulin-ß3 expression was correlated with negative PTEN expression. TUBB3 expression was increased in neuroendocrine CaP based on several public databases. PTEN knockout decreased the sensitivity to enzalutamide and apalutamide in 22Rv-1 cells. TUBB3 knockdown reversed the sensitivity to enzalutamide and apalutamide in PTEN-CRISPR 22Rv-1 cells. High expression of tubulin-ß3 and negative expression of PTEN were significantly associated with poor overall survival in metastatic CaP treated with androgen deprivation therapy. CONCLUSIONS: These results suggest that TUBB3 may be a useful predictive biomarker for survival and play an essential role in antiandrogen resistance in CaP.

Pten regulates collagen fibrillogenesis by fibroblasts through SPARC.

Collagen deposition contributes to both high mammographic density and breast cancer progression. Low stromal PTEN expression has been observed in as many as half of breast tumors and is associated with increases in collagen deposition, however the mechanism connecting PTEN loss to increased collagen deposition remains unclear. Here, we demonstrate that Pten knockout in fibroblasts using an Fsp-Cre;PtenloxP/loxP mouse model increases collagen fiber number and fiber size within the mammary gland. Pten knockout additionally upregulated Sparc transcription in fibroblasts and promoted collagen shuttling out of the cell. Interestingly, SPARC mRNA expression was observed to be significantly elevated in the tumor stroma as compared to the normal breast in several patient cohorts. While SPARC knockdown via shRNA did not affect collagen shuttling, it notably decreased assembly of exogenous collagen. In addition, SPARC knockdown decreased fibronectin assembly and alignment of the extracellular matrix in an in vitro fibroblast-derived matrix model. Overall, these data indicate upregulation of SPARC is a mechanism by which PTEN regulates collagen deposition in the mammary gland stroma.

Curcumin suppresses tumor growth of gemcitabine-resistant non-small cell lung cancer by regulating lncRNA-MEG3 and PTEN signaling.

BACKGROUND: Lung cancer is one of the most aggressive malignancies and the efficacy of chemotherapy or concurrent chemoradiation is limited in clinical application. Curcumin has been reported to block cancer development by modulating multiple signaling pathways. However, whether curcumin can inhibit gemcitabine-resistant non-small cell lung cancer through regulation of lncRNA and the involved molecular mechanisms are rarely reported. MATERIALS AND METHODS: MTT assay, clonogenic assay, apoptosis assay, qRT-PCR, Western blotting, immunohistochemistry, xenograft experiment were carried out in the present study. RESULTS: The results showed that curcumin suppressed gemcitabine-resistant non-small cell lung cancer cell proliferation and induced apoptosis. Curcumin upregulated the expression of lncRNA-MEG3 and PTEN, and MEG3 overexpression could increase the level of PTEN expression, while MEG3 knockdown decreased the level of PTEN expression in gemcitabine-resistant non-small cell lung cancer cells. Curcumin treatment failed to inhibit the proliferation and induce apoptosis in MEG3 knockdown or PTEN knockdown cells. CONCLUSIONS: These findings show the antitumor activity of curcumin for potential clinical application in gemcitabine-resistant non-small cell lung cancer treatment.

Downregulation of HOXA11 enhances endometrial cancer malignancy and cisplatin resistance via activating PTEN/AKT signaling pathway.

PURPOSE: Endometrial cancer is the most common malignant tumor of female genital system worldwide. Homeobox A11 (HOXA11) is an evolutionarily conserved Homeobox gene closely implicated in carcinogenesis. However, the mechanisms of HOXA11 in the progression and cisplatin resistance of endometrial cancer remain unclear. METHODS: The expression of HOXA11 was analyzed based on 548 endometrial cancer and 35 control tissues from The Cancer Genome Atlas (TCGA) database. Transwell assay was performed to investigate the effect of HOXA11 on endometrial cell migration and invasion. TUNEL staining was carried out to assay the role of HOXA11 in endometrial cell apoptosis. Western blot was employed to detect the protein levels of B cell lymphoma-2 (Bcl-2), Bcl-2 associated X (Bax), cleaved caspase-3, matrix metalloproteinase-2/9 (MMP/9), phosphatase and tensin homolog (PTEN), protein kinase B (AKT) and p-AKT. RESULTS: TCGA data showed that HOXA11 expression was significantly down-regulated in endometrial cancer tissue samples. The overexpression of HOXA11 promoted the apoptosis, but inhibited the proliferation, migration and invasion of endometrial cancer cells. HOXA11 knockdown with small interfering RNA (siRNA) considerably repressed cell apoptosis, while promoted cell proliferation, migration, and invasion through PTEN/AKT signaling pathway. Interestingly, HOXA11 was lowly expressed in Ishikawa cells treated with cisplatin. In addition, HOXA11 knockdown increased the resistance of endometrial cancer to cisplatin through activating PTEN/AKT signaling pathway. CONCLUSION: Low HOXA11 expression may promote the proliferation, migration, invasion of endometrial cancer cells, and increase their resistance to cisplatin through activating PTEN/AKT pathway.

FRMD6 has tumor suppressor functions in prostate cancer.

Available tools for prostate cancer (PC) prognosis are suboptimal but may be improved by better knowledge about genes driving tumor aggressiveness. Here, we identified FRMD6 (FERM domain-containing protein 6) as an aberrantly hypermethylated and significantly downregulated gene in PC. Low FRMD6 expression was associated with postoperative biochemical recurrence in two large PC patient cohorts. In overexpression and CRISPR/Cas9 knockout experiments in PC cell lines, FRMD6 inhibited viability, proliferation, cell cycle progression, colony formation, 3D spheroid growth, and tumor xenograft growth in mice. Transcriptomic, proteomic, and phospho-proteomic profiling revealed enrichment of Hippo/YAP and c-MYC signaling upon FRMD6 knockout. Connectivity Map analysis and drug repurposing experiments identified pyroxamide as a new potential therapy for FRMD6 deficient PC cells. Finally, we established orthotropic Frmd6 and Pten, or Pten only (control) knockout in the ROSA26 mouse prostate. After 12 weeks, Frmd6/Pten double knockouts presented high-grade prostatic intraepithelial neoplasia (HG-PIN) and hyperproliferation, while Pten single-knockouts developed only regular PIN lesions and displayed lower proliferation. In conclusion, FRMD6 was identified as a novel tumor suppressor gene and prognostic biomarker candidate in PC.

HBV down-regulates PTEN expression via Nrf2/GSK3ß signaling pathway. / HBV通过Nrf2/GSK3ß信号通路下调PTEN的表达.

OBJECTIVES: To investigate the effect of HBV infection on PTEN expression, and to explore the possible molecular mechanisms. METHODS: HepG2 cells and HepG2.2.15 cells were cultured under suitable conditions for 48 hours, and the expressions of PTEN, Nrf2 and pGSK3ß in HepG2 and HepG2.2.15 cells were detected by Western blotting. After the blank plasmid (EV) and the plasmid pWXL-Nrf2 were transiently transfected into HepG2 and HepG2.2.15 cells, respectively, the HepG2 and HepG2.2.15 cells were treated with the selective inhibitor of GSK3ß (25 nmol/L LiCl). After 48 h, the expressions of Nrf2, pGSK3ß and PTEN in HepG2 and HepG2.2.15 cells were examined by Western blotting. RESULTS: Expression of PTEN was reduced and the levels of Nrf2 and pGSK3ß were increased in HepG2.2.15 cells compared with those in the HepG2 cells (all P<0.05). After transfection with pWXL-Nrf2, the protein expression of Nrf2 and pGSK3ß in cells were significantly increased while the protein expression of PTEN was decreased (all P<0.05). Furthermore, LiCl treatment up-regulated the protein expression of Nrf2 and pGSK3ß, and eventually suppressed the production of PTEN (all P<0.05). CONCLUSIONS: HBV may down-regulate PTEN expression via Nrf2/GSK3ß signaling pathway, which may provide new ideas for the targeting therapy of hepatocellular carcinoma.