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LZTFL1 is a tumor suppressor located in chromosomal region 3p21.3 that is deleted frequently and early in various cancer types including the kidney cancer. However, its role in kidney tumorigenesis remains unknown. Here we hypothesized a tumor suppressive function of LZTFL1 in clear cell renal cell carcinoma (ccRCC) and its mechanism of action based on extensive bioinformatics analysis of patients’ tumor data and validated it using both gain- and loss-functional studies in kidney tumor cell lines and patient-derive xenograft (PDX) model systems. Our studies indicated that LZTFL1 inhibits kidney tumor cell proliferation by destabilizing AKT through ZNRF1-mediated ubiquitin proteosome pathway and inducing cell cycle arrest at G1. Clinically, we found that LZTFL1 is frequently deleted in ccRCC. Downregulation of LZTFL1 is associated with a poor ccRCC outcome and may be used as prognostic maker. Furthermore, we show that overexpression of LZTFL1 in PDX via lentiviral delivery suppressed PDX growth, suggesting that re-expression of LZTFL1 may be a therapeutic strategy against ccRCC.

Shortening of the 3′ untranslated regions (3′UTR) of mRNA is an important mechanism for oncogene activation. However, 3′UTR alteration events, their pathologic functions, and underlying mechanisms in human urothelial carcinoma of the bladder (UCB) are not clear. Here, we combine RNA sequencing, bioinformatics, and clinical studies in two independent cohorts of patients with UCB to identify a novel RAC1 shorter 3′UTR isoform that is frequently expressed in UCB and is critical in the tumorigenesis and acquisition of a poor prognostic phenotype in patients. Short 3′UTR isoform of RAC1 substantially upregulated RAC1 expression by escaping from miRNA-targeted repression and played an essential oncogenic role in UCB pathogenesis. An important cleavage/polyadenylation factor, cleavage stimulation factor 2 (CSTF2), induced 3′UTR shortening of RAC1 in UCB by mediating slow transcriptional elongation at RAC1. Cotranscriptional recruitment of CSTF2 on the GUAAU motif at proximal polyadenylation site of RAC1 attenuated the recruitment of two transcription factors AFF1 and AFF4, causing the defects in elongation. CSTF2 regulated the tumorigenic functions of the shorter RAC1 isoform in UCB cells, enhancing cell proliferation, migration, and invasion. The combination of high expression of CSTF2 and high usage of RAC1 short-3′UTR isoform may be used as a powerful biomarker to predict poor prognosis in UCB. Our findings also suggest a CSTF2-regulated RAC1-3′UTR shortening program as an exploitable therapeutic strategy for patients with UCB.Significance: These findings demonstrate that the short isoform of RAC1 is critical in UCB tumorigenesis and may have implications for developing new therapeutic strategies to treat this disease. Cancer Res; 78(20); 5848–62. ©2018 AACR.

Supplementary Figure S1. Identification of 3'UTR shortening of RALA and RAC1 from UCB, colorectal carcinoma, hepatocellular carcinoma and non-small cell lung cancer samples. Supplementary Figure S2. RAC1 with short 3'UTR promotes tumorigenesis and produces more protein due to evasion of miRNA-mediated repression. Supplementary Figure S3. Screening of APA factors that contribute to the PAS selection of RAC1 in UCB. Supplementary Figure S4. CSTF2 regulates colony formation and invasiveness abilities of shorter RAC1 isoform in UCB. Supplementary Table S1. PDUI value calculated from DaPars analysis of 15 pairs of UCB and adjacent normal bladder tissues. Supplementary Table S2. KEGG pathway analyses of APA genes identified from RNA-Seq. Supplementary Table S3. RAC1 genomic mutations identified from TCGA UCB database. Supplementary Table S4. Correlation between the expression of CSTF2 and clinicopathologic characteristics of UCB patients

Low levels of ITLN1 have been correlated with obesity-related colorectal carcinogenesis, however, the specific functions and underlying mechanisms remain unclear. Thus, we sought to explore the inhibitory role of ITLN1 in the tumor-permissive microenvironment that exists during the first occurrence and subsequent development of colorectal carcinoma (CRC). Results indicated that ITLN1 was frequently lost in CRC tissues and ITLN1 to be an independent prognostic predictor of CRC. Orthotopic and subcutaneous tumor xenograft approaches were then used to further confirm the protective role of ITLN1 during tumor progression. Increased ITLN1 expression in CRC cells significantly inhibited local pre-existing vessels sprouting, EPC recruitment and the infiltration of immunosuppressive myeloid-derived suppressor cells (MDSCs) into tumor tissues without affecting the behavior of CRC cells in vitro. Comparatively, ITLN1-derived MDSCs had a lower suppressive effect on T cell proliferation, NOS2 expression, and ROS production. In addition, ITLN1 overexpression markedly suppressed bone marrow (BM)-derived hematopoietic progenitor cells (HPC) differentiation into MDSCs as well as NOS2 activity on MDSCs. Using H-2b+YFP + chimerism through bone marrow transplantation, increased ITLN1 in HCT116 significantly reduced the BM-derived EPCs and MDSCs in vivo mobilization. Mechanistically, results indicated ITLN1 inhibited tumor-derived IL-17D and CXCL2 (MIP2) through the KEAP1/Nrf2/ROS/IL-17D and p65 NF-ĸB/CXCL2 signaling cascades dependent on PI3K/AKT/GSK3s. This effect was reversed by the PI3K selective inhibitor LY294002. Collectively, ITLN1 synergistically suppressed IL-17D and CXCL2-mediated tumor vascularization, bone marrow derived EPC recruitment, as well as MDSCs generation and trafficking. Thus, ITLN1 potentially serves as a critical prognostic and therapeutic target for CRC.

Translational reprogramming is part of the unfolded protein response (UPR) during endoplasmic reticulum (ER) stress, which acts to the advantage of cancer growth and development in different stress conditions, but the mechanism of ER stress-related translational reprogramming in colorectal carcinoma (CRC) progression remains unclear. Here, we identified that Krüppel-like factor 16 (KLF16) can promote CRC progression and stress tolerance through translational reprogramming. The expression of KLF16 was upregulated in CRC tissues and associated with poor prognosis for CRC patients. We found that ER stress inducers can recruit KLF16 to the nucleolus and increase its interaction with two essential proteins for nucleolar homeostasis: nucleophosmin1 (NPM1) and fibrillarin (FBL). Moreover, knockdown of KLF16 can dysregulate nucleolar homeostasis in CRC cells. Translation-reporter system and polysome profiling assays further showed that KLF16 can effectively promote cap-independent translation of ATF4, which can enhance ER-phagy and the proliferation of CRC cells. Overall, our study unveils a previously unrecognized role for KLF16 as an ER stress regulator through mediating translational reprogramming to enhance the stress tolerance of CRC cells and provides a potential therapeutic vulnerability.

Rationale: The incidence of hepatocellular carcinoma is rising worldwide. It is predicted that nearly half of the early-stage hepatocellular carcinoma (E-HCC) patients will develop recurrence. Dysregulated pH, a hallmark of E-HCC, is correlated with poor prognosis. The acidic microenvironment has been shown to promote the release of exosomes, the membrane vesicles recognized as intercellular communicators associated with tumor progression, recurrence, and metastasis. We, therefore, aimed to identify exosomes induced by acidic microenvironment that may regulate E-HCC progression and to explore their mechanisms and clinical significance in E-HCCs. Methods: miRNA microarray analysis and LASSO logistic statistic model were used to identify the main functional exosomal miRNAs. Invasion and scratch assays were performed to examine the migration and invasion of HCC cells. Immunoblotting and immunofluorescence were employed to detect the epithelial-to-mesenchymal transition (EMT) in HCC cells. Chromatin immunoprecipitation (ChIP) was used to analyze the binding of HIF-1α and HIF-2α to promoter regions of miR-21 and miR-10b. Results: The acidic microenvironment in HCC was correlated with poor prognosis of patients. Exosomes from HCC cells cultured in the acidic medium could promote cell proliferation, migration, and invasion of recipient HCC cells. We identified miR-21 and miR-10b as the most important functional miRNAs in acidic HCC-derived exosomes. Also, the acidic microenvironment triggered the activation of HIF-1α and HIF-2α and stimulated exosomal miR-21 and miR-10b expression substantially promoting HCC cell proliferation, migration, and invasion both in vivo and in vitro. In E-HCC patients, serum exosomal miR-21 and miR-10b levels were associated with advanced tumor stage and HIF-1α and HIF-2α expression and were independent prognostic factors for disease-free survival of E-HCC patients. Most importantly, we developed a nano-drug to target exosomal miR-21 and/or miR-10b and examined its therapeutic effects against HCC in vivo. Conclusion: Our findings suggested that the exosomal miR-21 and miR-10b induced by acidic microenvironment in HCC promote cancer cell proliferation and metastasis and may serve as prognostic molecular markers and therapeutic targets for HCC.

Endocrine therapy is one of the main treatments for estrogen receptor-positive breast cancers. Tamoxifen is the most commonly used drug for endocrine therapy. However, primary or acquired tamoxifen resistance occurs in a large proportion of breast cancer patients, leading to therapeutic failure. We found that the combination of tamoxifen and ACT001, a nuclear factor-κB (NF-κB) signaling pathway inhibitor, effectively inhibited the proliferation of both tamoxifen-sensitive and tamoxifen-resistant cells. The tamoxifen-resistant cell line MCF7R/LCC9 showed active NF-κB signaling and high apoptosis-related gene transcription, especially for antiapoptotic genes, which could be diminished by treatment with ACT001. These results demonstrate that ACT001 can prevent and reverse tamoxifen resistance by inhibiting NF-κB activation.

Low levels of ITLN1 have been correlated with obesity-related colorectal carcinogenesis, however, the specific functions and underlying mechanisms remain unclear. Thus, we sought to explore the inhibitory role of ITLN1 in the tumor-permissive microenvironment that exists during the first occurrence and subsequent development of colorectal carcinoma (CRC). Results indicated that ITLN1 was frequently lost in CRC tissues and ITLN1 to be an independent prognostic predictor of CRC. Orthotopic and subcutaneous tumor xenograft approaches were then used to further confirm the protective role of ITLN1 during tumor progression. Increased ITLN1 expression in CRC cells significantly inhibited local pre-existing vessels sprouting, EPC recruitment and the infiltration of immunosuppressive myeloid-derived suppressor cells (MDSCs) into tumor tissues without affecting the behavior of CRC cells in vitro. Comparatively, ITLN1-derived MDSCs had a lower suppressive effect on T cell proliferation, NOS2 expression, and ROS production. In addition, ITLN1 overexpression markedly suppressed bone marrow (BM)-derived hematopoietic progenitor cells (HPC) differentiation into MDSCs as well as NOS2 activity on MDSCs. Using H-2b+YFP + chimerism through bone marrow transplantation, increased ITLN1 in HCT116 significantly reduced the BM-derived EPCs and MDSCs in vivo mobilization. Mechanistically, results indicated ITLN1 inhibited tumor-derived IL-17D and CXCL2 (MIP2) through the KEAP1/Nrf2/ROS/IL-17D and p65 NF-ĸB/CXCL2 signaling cascades dependent on PI3K/AKT/GSK3ß. This effect was reversed by the PI3K selective inhibitor LY294002. Collectively, ITLN1 synergistically suppressed IL-17D and CXCL2-mediated tumor vascularization, bone marrow derived EPC recruitment, as well as MDSCs generation and trafficking. Thus, ITLN1 potentially serves as a critical prognostic and therapeutic target for CRC.

Background Metastasis causes the vast majority of colorectal carcinoma (CRC)-related deaths. However, little is known about the specific traits and underlying mechanisms of metastasis-initiating cells in primary CRC. And whether or not circular RNAs (circRNAs) take part in this particular event remain not adequately stated yet. Methods A screening method based on Transwell assay was first applied to build CRC subgroups with different metastatic potential. High throughput RNA sequencing was used to find out novel metastatic drivers in CRC metastasis-initiating step. A series of in vitro and in vivo assays were further applied to elucidate the functions and underlying molecular mechanisms of circRNAs in CRC metastasis. Results A circRNA consisting of exon 8–11 of LONP2, termed as circLONP2, was upregulated in metastasis-initiating CRC subgroups. Aberrant higher expression of circLONP2 was observed in primary CRC tissues with established metastasis, and along the invasive margin in metastatic site. High expression of circLONP2 predicted unfavorable overall survival. Functional studies revealed that circLONP2 could enhance the invasiveness of CRC cells in vitro, and targeting circLONP2 through anti-sense oligonucleotide (ASO) dramatically reduced the penetrance of metastasis to foreign organs in vivo. Mechanically, circLONP2 directly interacted with and promoted the processing of primary microRNA-17 (pri-miR-17), through recruiting DiGeorge syndrome critical region gene 8 (DGCR8) and Drosha complex in DDX1-dependent manner. Meanwhile, upregulated mature miR-17-5p could be assembled into exosomes and internalized by neighboring cells to enhance their aggressiveness. Conclusions Our data indicate that circLONP2 acts as key metastasis-initiating molecule during CRC progression through modulating the intracellular maturation and intercellular transfer of miR-17, resulting in dissemination of metastasis-initiating ability in primary site and acceleration of metastasis formation in foreign organs. circLONP2 could serve as an effective prognostic predictor and/or novel anti-metastasis therapeutic target in CRC treatment.

Shortening of the 3′ untranslated regions (3′UTR) of mRNA is an important mechanism for oncogene activation. However, 3′UTR alteration events, their pathologic functions, and underlying mechanisms in human urothelial carcinoma of the bladder (UCB) are not clear. Here, we combine RNA sequencing, bioinformatics, and clinical studies in two independent cohorts of patients with UCB to identify a novel RAC1 shorter 3′UTR isoform that is frequently expressed in UCB and is critical in the tumorigenesis and acquisition of a poor prognostic phenotype in patients. Short 3′UTR isoform of RAC1 substantially upregulated RAC1 expression by escaping from miRNA-targeted repression and played an essential oncogenic role in UCB pathogenesis. An important cleavage/polyadenylation factor, cleavage stimulation factor 2 (CSTF2), induced 3′UTR shortening of RAC1 in UCB by mediating slow transcriptional elongation at RAC1. Cotranscriptional recruitment of CSTF2 on the GUAAU motif at proximal polyadenylation site of RAC1 attenuated the recruitment of two transcription factors AFF1 and AFF4, causing the defects in elongation. CSTF2 regulated the tumorigenic functions of the shorter RAC1 isoform in UCB cells, enhancing cell proliferation, migration, and invasion. The combination of high expression of CSTF2 and high usage of RAC1 short-3′UTR isoform may be used as a powerful biomarker to predict poor prognosis in UCB. Our findings also suggest a CSTF2-regulated RAC1-3′UTR shortening program as an exploitable therapeutic strategy for patients with UCB. Significance: These findings demonstrate that the short isoform of RAC1 is critical in UCB tumorigenesis and may have implications for developing new therapeutic strategies to treat this disease. Cancer Res; 78(20); 5848–62. ©2018 AACR.

// Wei-Juan Huang 1, 2, * , Mei Li 3, * , Xiao-Han Jin 4, * , Xiao-Jia Huang 1 , Wei Zhao 1 and Xiao-Peng Tian 1, 4 1 Department of Histology and Embryology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China 2 Department of Pharmacology, Jinan University, Guangzhou, China 3 Department of Pathology, Cancer Center, Sun Yat-Sen University, Guangzhou, China 4 The State Key Laboratory of Oncology in South China, Sun Yat-Sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China * These authors have contributed equally to this work Correspondence to: Xiao-Peng Tian, email: aldrichtian@163.com Keywords: PinX1, cancer, expression pattern, function, cBioportal Received: April 11, 2017 Accepted: May 03, 2017 Published: June 21, 2017 ABSTRACT Pin2/TRF1-interacting telomere inhibitor 1 (PinX1) was originally identified as a telomerase inhibitor, involved in maintaining telomerase activity, telomere length, and chromosomal stability. However, research has shown that PinX1 can have opposing molecular status in its expression patterns in several other tumor types. We thus investigated the genetic profile and biological implication of PinX1 in several human cancers using the cBioportal database. Our results showed that PinX1 deletion accounted for the most alterations, with the frequency of its deletion regularly occurring in pathological types of carcinosarcoma and adenocarcinoma. We found few instances of PinX1 gene mutations and 3D structural analysis demonstrated that these mutation sites were always located within telomerase inhibitor domains. Furthermore, our analysis of several human cancers from the cBioportal database revealed more frequent PinX1 homozygous depletion and PinX1 heterozygous deficiency, but both more infrequent PinX1 gain and rare instances of PinX1 amplification. The status of PinX1 genetic alterations was correlated with prognosis and may be tumor-type specific. As such, its biological function in tumorigenesis and later prognosis is complicated and may involve co-worked with NEIL2, R3HCC1, POLR3D, GTF2E2, and INTS10. In addition, we observed that PinX1 interacts with TERT, DKC1, PTGES3, and HSP90AA1. PinX1 mRNA expression was decreased in most selected cancer tissues, which could promote tumor growth and enhance tumorigenicity. Collectively, our data reveal PinX1 expression patterns and potential mechanisms in various human cancers. Further work will be needed to comprehensively examine its role in tumor genesis and progression.

This work presents a new type of coating system based on the use of electrodeposited SiO 2 (E-SiO 2 ) film post-treated with (3-glycidoxypropyl)-trimethoxysilane (GPTMS) as the pretreatment layer. The silane-modified E-SiO 2 films take advantage of not only the highly rough and porous features provided by E-SiO 2 skeleton, but also the chemical functionalization offered by organosilane molecule. As a result, the composite pretreatment layer provides improved adhesion to the topcoat. In addition, the experimental results of electrochemical impedance spectroscopy, salt spray test, iron-dissolution measurement and the scanning vibrating electrode technique suggest that painting system constructed on GPTMS-treated E-SiO 2 films exhibits excellent corrosion performance.

The adenomatous polyposis coli (APC) gene plays a pivotal role in the pathogenesis of colorectal carcinoma (CRC) but remains a challenge for drug development. Long noncoding RNAs (lncRNAs) are invaluable in identifying cancer pathologies and providing therapeutic options for patients with cancer. Here, we identified a lncRNA (lncRNA-APC1) activated by APC through lncRNA microarray screening and examined its expression in a large cohort of CRC tissues. A decrease in lncRNA-APC1 expression was positively associated with lymph node and/or distant metastasis, a more advanced clinical stage, as well as a poor prognosis for patients with CRC. Additionally, APC could enhance lncRNA-APC1 expression by suppressing the enrichment of PPARα on the lncRNA-APC1 promoter. Furthermore, enforced lncRNA-APC1 expression was sufficient to inhibit CRC cell growth, metastasis, and tumor angiogenesis by suppressing exosome production through the direct binding of Rab5b mRNA and a reduction of its stability. Importantly, exosomes derived from lncRNA-APC1–silenced CRC cells promoted angiogenesis by activating the MAPK pathway in endothelial cells, and, moreover, exosomal Wnt1 largely enhanced CRC cell proliferation and migration through noncanonicial Wnt signaling. Collectively, lncRNA-APC1 is a critical lncRNA regulated by APC in the pathogenesis of CRC. Our findings suggest that an APC-regulated lncRNA-APC1 program is an exploitable therapeutic approach for the treatment of patients with CRC.

Shortening of the 3' untranslated regions (3'UTR) of mRNA is an important mechanism for oncogene activation. However, 3'UTR alteration events, their pathologic functions, and underlying mechanisms in human urothelial carcinoma of the bladder (UCB) are not clear. Here, we combine RNA sequencing, bioinformatics, and clinical studies in two independent cohorts of patients with UCB to identify a novel

It has been suggested that formin-like protein 1 (FMNL1) plays an important role in the pathogenic process of several hematopoietic malignancies. In this study, we performed a series of in vivo and in vitro assays to elucidate the biological functions of FMNL1 and underlying mechanisms in human nasopharyngeal carcinoma (NPC) pathogenesis. Herein, we report that high expression of FMNL1 in NPC is positively associated with an aggressive disease and/or poor patient survival. Ectopic overexpression of FMNL1 in NPC cells substantially promoted cell invadopodia formation, epithelial-mesenchymal transition (EMT) and invasiveness, whereas depletion of FMNL1 potently suppressed NPC cells invadopodia formation, EMT, and invasive/metastatic capacities. We further show that FMNL1 could enhance NPC cell aggressiveness by increasing a key downstream target, the metastasis-associated protein 1 (MTA1) gene. Importantly, ectopic overexpression of FMNL1 in NPC cells markedly improved the binding of HDAC1 with Profilin2 in the cytoplasm and suppressed the enrichment of HDAC1 on the promoter of MTA1 and thereby, leading to an increased MTA1 transcription and expression. Furthermore, in addition to the amplification of FMNL1 gene, decreased level of miR-16 in NPCs is another critical mechanism to upregulate FMNL1 expression. These results, collectively, provide first-line of evidences that high expression of FMNL1, resulted from decreased miR-16 and/or MTA1 amplification, has a potent oncogenic role to drive the development and aggressive process of NPC by upregulating MTA1, and FMNL1 might be employed as a new prognostic biomarker and therapeutic target for human NPC.

AGBL2 has been reported to catalyze α-tubulin detyrosination, by which it promotes tumorigenesis and cancer progression. However, its potential role in the pathogenesis of hepatocellular carcinoma (HCC) has not been revealed yet. In the present study, AGBL2 was frequently found being overexpressed in HCC tissues and cell lines. In a large cohort of clinical HCC tissues, high expression of AGBL2 was positively associated with tumor size, tumor multiplicity and advanced clinical stage (p

Cancer stem cells (CSCs)/cancer-initiating cells (CICs) are suggested responsible for driving cancer resistance to conventional therapies and for cancer recurrence and/or metastasis. CD133 is served as a key biomarker to identify and characterize this subpopulation of cells in hepatocellular carcinoma (HCC). Our previous study indicated that overexpression of eukaryotic initiation factor 5A2 (EIF5A2) promotes HCC cell metastasis and angiogenesis. In this study, we demonstrated that EIF5A2 might play a crucial role in CSCs regulation and investigated its potential molecular mechanisms. Using quantitative real-time polymerase chain reaction assay, we observed that the expression of EIF5A2 positively correlated with CD133 levels in a cohort of cancerous and noncancerous liver tissues and cells. Next, HCC cells with high expression of EIF5A2 have a strong capacity to form undifferentiated tumor spheres in vitro and show elevated levels of stem cell-related genes, leading to an increased ability to develop tumors when subcutaneously injected into nude mice. Furthermore, differential microRNA expression was profiling between two EIF5A2-depleted HCC cell lines and their control one identified a decreased expression of miR-29b in EIF5A2-depleted cell lines. Further functional studies illustrated that downregulated miR-29b level is responsible for EIF5A2-maintained HCC cell stemness either in vitro or in vivo. Moreover, enforced expression of EIF5A2 in HCC cells largely enhanced the binding of c-Myc on the promoter of miR-29b and downregulation of miR-29b by EIF5A2 was dependent on c-Myc. Our findings, collectively, reveal that EIF5A2 contributes to the maintenance of CD133+ HCC cells via the c-Myc/miR-29b axis.

Zing finger protein 580 (ZFP580) is a novel Cys2-His2 zinc-finger transcription factor that has an anti-apoptotic role in myocardial cells. It is involved in the endothelial transforming growth factor‑β1 (TGF‑β1) signal transduction pathway as a mothers against decapentaplegic homolog (Smad)2 binding partner. The aim of the present study was to determine the involvement of ZFP580 in TGF‑β1‑mediated cytoprotection against chemical hypoxia‑induced apoptosis, using H9c2 cardiac myocytes. Hypoxia was chemically induced in H9c2 myocardial cells by exposure to cobalt chloride (CoCl2). In response to hypoxia, cell viability was decreased, whereas the expression levels of hypoxia inducible factor-1α and ZFP580 were increased. Pretreatment with TGF‑β1 attenuated CoCl2‑induced cell apoptosis and upregulated ZFP580 protein expression; however, these effects could be suppressed by SB431542, an inhibitor of TGF‑β type I receptor and Smad2/3 phosphorylation. Furthermore, suppression of ZFP580 expression by RNA interference reduced the anti‑apoptotic effects of TGF‑β1 and thus increased CoCl2‑induced apoptosis. B‑cell lymphoma (Bcl)‑2‑associated X protein/Bcl‑2 ratio, reactive oxygen species generation and caspase‑3 activation were also increased following ZFP580 inactivation. In conclusion, these results indicate that ZFP580 is a component of the TGF-β1/Smad signaling pathway, and is involved in the protective effects of TGF‑β1 against chemical hypoxia‑induced cell apoptosis, through inhibition of the mitochondrial apoptotic pathway.

Trimethylation of lysine 27 on histone H3 (H3K27ME3) is a transcription-suppressive histone mark mediated by enhancer of zeste homolog 2 (EZH2). We have previously suggested that EZH2-mediated H3K27ME3 plays a critical oncogenic role in human hepatocellular carcinoma (HCC) aggressiveness. However, the direct downstream targets of EZH2-H3K27ME3 and the molecular mechanisms by which regulates HCC pathogenesis remain unclear. In this study, we used chromatin immunoprecipitation together with high-throughput sequencing (ChIP-seq) and gene expression profiling by microarray analysis to assess genome-wide chromatin occupancy of H3K27ME3 in HCC cells. We identified that claudin14 (CLDN14) is a potentially direct target for EZH2-mediated H3K27ME3 in HCC. In a large cohort of clinical HCC tissues, we found that low expression of CLDN14 was significantly associated with advanced tumor stage and determined to be an independent predictor of shortened survival of HCC patients. Next, functional experiment demonstrated that depletion of CLDN14 substantially restored EZH2-silenced HCC cells motility and invasive capacities and supported cell epithelial-mesenchymal transition (EMT). Furthermore, downregulation of CLDN14 dramatically re-enhanced the wnt/β-catenin signaling activity in EZH2-silenced HCC cells by increasing the levels of active β-catenin and promoting the nuclear localization of β-catenin. These results, collectively, uncover that CLDN14 is a novel direct target of EZH2-mediated H3K27ME3, and provide an explanation for the aggressive nature of HCC with downregulation of CLDN14 and the underling mechanism that links the tumor suppressor CLDN14 to the wnt/β-catenin signaling pathway.

We have recently identified and characterized a novel oncogene, maelstrom (MAEL) from 1q24, in the pathogenesis of hepatocellular carcinoma. In this study, MAEL was investigated for its oncogenic role in urothelial carcinoma of the bladder (UCB) tumorigenesis/aggressiveness and underlying molecular mechanisms. Here, we report that overexpression of MAEL in UCB is important in the acquisition of an aggressive and/or poor prognostic phenotype. In UCB cell lines, knockdown of MAEL by short hairpin RNA is sufficient to inhibit cell growth, invasiveness/metastasis and suppressed epithelial-mesenchymal transition (EMT), whereas ectopic overexpression of MAEL promoted cell growth, invasive and/or metastatic capacity and enhanced EMT both in vitro and in vivo. We further demonstrate that MAEL could induce UCB cell EMT by downregulating a critical downstream target, the metastasis suppressor 1 (MTSS1) gene, ultimately leading to an increased invasiveness of cancer cells. Notably, overexpression of MAEL in UCB cells substantially enhanced the enrichment of DNA methyltrans-ferase (DNMT)3B and histone deacetylase (HDAC)1/2 on the promoter of the MTSS1, and thereby epigenetically suppressing the MTSS1 transcription. Downregulation of MTSS1 by MAEL in UCB cells is partially dependent on DNMT3B. Furthermore, we identify that beside the gene amplification of MAEL, miR-186 is a key negative regulator of MAEL and downregulation of miR-186 is another important mechanism for MAEL overexpression in UCBs. These data suggest that overexpression of MAEL, caused by gene amplification and/or decreased miR-186, has a critical oncogenic role in UCB pathogenesis by downregulation of MTSS1, and MAEL could be used as a novel prognostic marker and/or effective therapeutic target for human UCB.

Background The telomerase/telomere interacting protein PinX1 has been suggested as a tumor suppressor. However, the clinical and biological significance of PinX1 in human non-small cell lung cancer (NSCLC) is unclear. Methods PinX1 gene/expression pattern and its association with NSCLC patient survival were analyzed in cBioportal Web resource and two cohorts of NSCLC samples. A series of in vivo and in vitro assays were performed to elucidate the function of PinX1 on NSCLC cells proliferation and underlying mechanisms. Results More frequency of gene PinX1 homozygous deletion and heterozygote deficiency was first retrieved from cBioportal Web resource. Low expression of PinX1 correlated with smoking condition, histological type, T stage, N stage, M stage and TNM stage, and was an independent predictor for overall survival in a learning cohort (n = 93) and a validation cohort (n = 51) of NSCLC patients. Furthermore, knockdown of PinX1 dramatically accelerated NSCLC cell proliferation and G1/S transition, whereas ectopic overexpression of PinX1 substantially inhibited cell viability and cell cycle transition in vitro and in vivo. p15/cyclin D1 pathway and BMP5 might contribute to PinX1-associated cell proliferation and cell cycle transition. Conclusion The cost-effective expression of PinX1 could constitute a novel molecular predictor/marker for NSCLC management. Electronic supplementary material The online version of this article (doi:10.1186/s12943-017-0637-4) contains supplementary material, which is available to authorized users.