microRNA-497 slows esophageal cancer development and reverses chemotherapy resistance through its target QKI.

Esophageal cancer (EC) is considered one of the most lethal cancers in human beings, and multiple miRNAs have been investigated to be involved in EC development by targeting their target genes. However, the function and related mechanism of miRNA-497 on EC tumorigenesis remain uncertain. This study first demonstrated that the expression levels of miR-497 in esophageal cancer specimens and cells were down-regulated. Forced expression of miR-497 inhibited cell proliferation, tube formation and migration in EC cells. To further investigate the potential molecular mechanism of miR-497 suppression in regulating EC, we found that miR-497 directly binds to the 3'-untranslational region of QKI, miR-497 overexpression suppressed QKI expression. We further found that overexpression of miR-497 enhanced the effect of chemotherapy in EC cell lines, and prevented the tumor growth of EC in vivo. Our findings indicated that miR-497 suppression increased QKI expression and therapeutic resistance of esophageal cancer, which is likely to be a biomarker of EC progression and potential therapeutic target.

MKRN2 knockout causes male infertility through decreasing STAT1, SIX4, and TNC expression.

Makorin-2 (Mkrn2) is an evolutionarily conserved gene whose biological functions are not fully known. Although recent studies have shed insights on the potential causes of male infertility, its underlining mechanisms still remain to be elucidated. We developed a Mrkn2 knockout mice model to study this gene and found that deletion of Mkrn2 in mice led to male infertility. Interestingly, the expression level of signal transducer and activator of the transcription (STAT)1 was significantly decreased in MKRN2 knockout testis and MEF cells. Co-IP assay showed an interaction between MKRN2 and STAT1. Moreover, our results further indicated that MKRN2 regulated the expression level of SIX4 and tenascin C (TNC) via the EBF transcription factor 2 (EBF2) in mice. The results of our study will provide insights into a new mechanism of male infertility.

METTL3-mediated N6-methyladenosine modification and HDAC5/YY1 promote IFFO1 downregulation in tumor development and chemo-resistance.

Ovarian cancer (OC) is a malignant tumor that seriously threatens women's health. Due to the difficulty of early diagnosis, most patients exhibit advanced disease or peritoneal metastasis at diagnosis. We discovered that IFFO1 is a novel tumor suppressor, but its role in tumorigenesis, development and chemoresistance is unknown. In this study, IFFO1 levels were downregulated across cancers, leading to the acceleration of tumor development, metastasis and/or cisplatin resistance. Overexpression of IFFO1 inhibited the translocation of ß-catenin to the nucleus and decreased tumor metastasis and cisplatin resistance. Furthermore, we demonstrated that IFFO1 was regulated at both the transcriptional and posttranscriptional levels. At the transcriptional level, the recruitment of HDAC5 inhibited IFFO1 expression, which is mediated by the transcription factor YY1, and the METTL3/YTHDF2 axis regulated the mRNA stability of IFFO1 in an m6A-dependent manner. Mice injected with IFFO1-overexpressing cells had lower ascites volumes and tumor weights throughout the peritoneal cavity than those injected with parental cells expressing the vector control. In conclusion, we demonstrated that IFFO1 is a novel tumor suppressor that inhibits tumor metastasis and reverses drug resistance in ovarian cancer. IFFO1 was downregulated at both the transcriptional level and posttranscriptional level by histone deacetylase and RNA methylation, respectively, and the IFFO1 signaling pathway was identified as a potential therapeutic target for cancer.

KIAA1429 regulates alternative splicing events of cancer-related genes in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) remains one of the most fatal malignancies with high morbidity and mortality rates in the world, whose molecular pathogenesis is incompletely understood. As an RNA-binding protein participating in the processing and modification of RNA, KIAA1429 has been proved to be implicated in the pathogenesis of multiple cancers. However, how KIAA1429 functions in alternative splicing is not fully reported. In the current study, multi-omics sequencing data were used to analyze and decipher the molecular functions and the underlying mechanisms of KIAA1429 in HCC samples. RNA sequencing data (RNA-seq) analysis demonstrated that in HCCLM3 cells, alternative splicing (AS) profiles were mediated by KIAA1429. Regulated AS genes (RASGs) by KIAA1429 were enriched in cell cycle and apoptosis-associated pathways. Furthermore, by integrating the RNA immunoprecipitation and sequencing data (RIP-seq) of KIAA1429, we found that KIAA1429-bound transcripts were highly overlapping with RASGs, indicating that KIAA1429 could globally regulate the alternative splicing perhaps by binding to their transcripts in HCCLM3 cells. The overlapping RASGs were also clustered in cell cycle and apoptosis-associated pathways. In particular, we validated the regulated AS events of three genes using clinical specimens from HCC patients, including the exon 6 of BPTF gene and a marker gene of HCC. In summary, our results shed light on the regulatory functions of KIAA1429 in the splicing process of pre-mRNA and provide theoretical basis for the targeted therapy of HCC.

Chromium (VI)-induced ALDH1A1/EGF axis promotes lung cancer progression.

Cr(VI) is broadly applied in industry. Cr(VI) exposure places a big burden on public health, thereby increasing the risk of lung squamous cell carcinoma (LUSC). The mechanisms underlying Cr(VI)-induced LUSC remain largely elusive. Here, we report that the cancer stem cell (CSC)/tumour-initiating cell (TIC)-like subgroup within Cr(VI)-transformed bronchial epithelial cells (CrT) promotes lung cancer tumourigenesis. Mechanistically, Cr(VI) exposure specifically increases the expression levels of aldehyde dehydrogenase 1A1 (ALDH1A1), a CSC marker, through KLF4-mediated transcription. ALDH1A1 maintains self-renewal of CrT/TICs and facilitates the expression and secretion of EGF from CrT/TICs, which subsequently promotes the activation of EGFR signalling in differentiated cancer cells and tumour growth of LUSC. In addition, the ALDH1A1 inhibitor A37 and gemcitabine synergistically suppress LUSC progression. Importantly, high ALDH1A1 expression levels are positively correlated with advanced clinical stages and predict poor survival in LUSC patients. These findings elucidate how ALDH1A1 modulates EGF secretion from TICs to facilitate LUSC tumourigenesis, highlighting new therapeutic strategies for malignant lung cancers.

Corrigendum: Regulation of microrna-497-targeting AKT2 influences tumor growth and chemoresistance to cisplatin in lung cancer.

[This corrects the article DOI: 10.3389/fcell.2020.00840.].

Green autofluorescence of the index fingernails is a novel biomarker for noninvasive determinations on the status of tobacco smoking.

It is critical to discover novel biomarkers for tobacco smoking. Our study has indicated the green autofluorescence (AF) of Index Fingernails as a novel biomarker for rapid and noninvasive determinations on the status of tobacco smoking: The green AF intensity of the Index Fingernails of the smokers was remarkably higher than that of the nonsmokers in the natural populations. When the AF intensity of the Fingernails was used as the variable, the area under curve (AUC) for differentiating the smokers from the nonsmokers was 0.91. Similar results were obtained by analyzing the green AF of the Index Fingernails of the healthy populations and the patients of acute ischemic stroke. Collectively, our study has indicated the green AF of the Index Fingernails as a novel biomarker for tobacco smoking, based on which the first method for noninvasive, rapid and economical determinations on the status of tobacco smoking may be established.

Epigenetic alterations of CXCL5 in Cr(VI)-induced carcinogenesis.

Chronic exposure to hexavalent chromium compounds [Cr(VI)] is associated with an increased risk of cancers, but the molecular mechanisms remain to be elucidated. In this study, we found that CXCL5 levels in peripheral blood monocytes (PBMCs) and plasma from workers with occupational exposure to Cr(VI) were dramatically upregulated compared to non-exposure healthy subjects, and plasma C-X-C Motif Chemokine Ligand 5 (CXCL5) CXCL5 levels were positively correlated with Cr concentrations in subjects' toenails. Zinc chromate exposed mice showed higher levels of CXCL5 and its receptor CXCR2 in lung tissues, and in PBMCs. Similar CXCL5 upregulation was evident in Cr(VI)-induced transformed (Cr-T) cells with long-term Cr(VI) treatment. Mechanistic studies showed that elevated CXCL5 expression levels were regulated by Cr(VI)-induced histone modifications and DNA hypomethylation, and that the c-Myc/p300 complex was a key upstream regulator of histone H3 acetylation. CXCL5 overexpression promoted Cr(VI)-induced the epithelial to mesenchyme transition (EMT) by upregulating zinc finger E-box binding homeobox 1 (ZEB1) to promote tumor development. Our findings identify a novel mechanism by which CXCL5 is upregulated and promotes EMT and carcinogenesis upon chronic Cr(VI) exposure. Our work also implies that CXCL5 mRNA and protein levels will elevate in PBMCs and serum after occupational Cr(VI) exposure, which may be a potential target and biomarker for cancer prevention and health surveillance among populations exposed to Cr(VI).

ROS and miRNA Dysregulation in Ovarian Cancer Development, Angiogenesis and Therapeutic Resistance.

The diverse repertoires of cellular mechanisms that progress certain cancer types are being uncovered by recent research and leading to more effective treatment options. Ovarian cancer (OC) is among the most difficult cancers to treat. OC has limited treatment options, especially for patients diagnosed with late-stage OC. The dysregulation of miRNAs in OC plays a significant role in tumorigenesis through the alteration of a multitude of molecular processes. The development of OC can also be due to the utilization of endogenously derived reactive oxygen species (ROS) by activating signaling pathways such as PI3K/AKT and MAPK. Both miRNAs and ROS are involved in regulating OC angiogenesis through mediating multiple angiogenic factors such as hypoxia-induced factor (HIF-1) and vascular endothelial growth factor (VEGF). The NAPDH oxidase subunit NOX4 plays an important role in inducing endogenous ROS production in OC. This review will discuss several important miRNAs, NOX4, and ROS, which contribute to therapeutic resistance in OC, highlighting the effective therapeutic potential of OC through these mechanisms.

Human endothelial cells promote arsenic-transformed lung epithelial cells to induce tumor growth and angiogenesis through interleukin-8 induction.

Arsenic exposure is associated with lung cancer. Angiogenesis is essential for tumor development. However, the role and mechanism of human vascular endothelial cells in tumor growth and angiogenesis induced by arsenic-transformed bronchial epithelial (As-T) cells remain to be elucidated. In this study, we found that endothelial cells significantly increased As-T cell-induced tumor growth compared to those induced by As-T cells alone. To understand the molecular mechanism, we found that endothelial cells co-cultured with As-T cells or cultured in conditioned medium (CM) prepared from As-T cells showed much higher cell migration, proliferation, and tube formation compared to those co-cultured with BEAS-2B (B2B) cells or cultured in CM from B2B. We identified that higher levels of intracellular interleukin 8 (IL-8) were secreted by As-T cells, which activated IL-8/IL-8R signaling to promote endothelial cells migration and tube formation. IL-8 silencing and knockout (KO) in As-T cells, or IL-8 neutralizing antibody dramatically suppressed endothelial cell proliferation, migration, tube formation in vitro, and tumor growth and angiogenesis in vivo, suggesting a key role of IL-8 in As-T cells to induce angiogenesis via a paracrine effect. Finally, blocking of IL-8 receptors C-X-C chemokine receptor type 1 (CXCR1) and CXCR2 with neutralizing antibodies and chemical inhibitors inhibited tube formation, indicating that IL-8Rs on endothelial cells are necessary for As-T cell-induced angiogenesis. Overall, this study reveals an important molecular mechanism of arsenic-induced carcinogenesis, and suggests a new option to prevent and treat arsenic-induced angiogenesis.

miR-196a Upregulation Contributes to Gefitinib Resistance through Inhibiting GLTP Expression.

Tyrosine kinase inhibitor (TKI) therapy has greatly improved lung cancer survival in patients with epidermal growth factor receptor (EGFR) mutations. However, the development of TKI-acquired resistance is the major problem to be overcome. In this study, we found that miR-196a expression was greatly induced in gefitinib-resistant lung cancer cells. To understand the role and mechanism of miR-196a in TKI resistance, we found that miR-196a-forced expression alone increased cell resistance to gefitinib treatment in vitro and in vivo by inducing cell proliferation and inhibiting cell apoptosis. We identified the transcription factor nuclear factor erythroid 2-related factor 2 (NRF2) bound to the promoter region of miR-196a and induced miR-196a expression at the transcriptional level. NRF2-forced expression also significantly increased expression levels of miR-196a, and was an upstream inducer of miR-196a to mediate gefitinib resistance. We also found that glycolipid transfer protein (GLTP) was a functional direct target of miR-196a, and downregulation of GLTP by miR-196a was responsible for gefitinib resistance. GLTP overexpression alone was sufficient to increase the sensitivity of lung cancer cells to gefitinib treatment. Our studies identified a new role and mechanism of NRF2/miR-196a/GLTP pathway in TKI resistance and lung tumor development, which may be used as a new biomarker (s) for TKI resistance or as a new therapeutic target in the future.

Reactive oxygen species reprogram macrophages to suppress antitumor immune response through the exosomal miR-155-5p/PD-L1 pathway.

BACKGROUND: Cancer cells have an imbalance in oxidation-reduction (redox) homeostasis. Understanding the precise mechanisms and the impact of the altered redox microenvironment on the immunologic reaction to tumors is limited. METHODS: We isolated exosomes from ovarian cancer cells through ultracentrifuge and characterized by Western-blots and Nanoparticle Tracking Analysis. 2D, 3D-coculture tumor model, and 3D live cell imaging were used to study the interactions between tumor cells, macrophages and CD3 T cells in vitro. The role of exosomal miR-155-5p in tumor growth was evaluated in xenograft nude mice models and immune-competent mice models. Flow cytometry and flow sorting were used to determine the expression levels of miR-155-5p and PD-L1 in ascites and splenic macrophages, and the percentages of CD3 T cells subpopulations. RESULTS: The elevation of reactive oxygen species (ROS) greatly downregulated exosomal miR-155-5p expression in tumor cells. Neutralization of ROS with N-acetyl-L-cysteine (NAC) increased the levels of miR-155-5p in tumor exosomes that were taken up by macrophages, leading to reduction of macrophage migration and tumor spheroid infiltration. We further found that programmed death ligand 1 (PD-L1) is a functional target of miR-155-5p. Co-culture of macrophages pre-treated with NAC-derived tumor exosomes or exosomal miR-155-5p with T-lymphocytes leading to an increased percentage of CD8+ T-lymphocyte and a decreased CD3+ T cell apoptosis through PD-L1 downregulation. Tumor growth in nude mice was delayed by treatment with NAC-derived tumor exosomes. Delivery of tumor exo-miR-155-5p in immune-intact mice suppressed ovarian cancer progression and macrophage infiltration, and activated CD8+ T cell function. It is of note that exo-miR-155-5p inhibited tumor growth more potently than the PD-L1 antibody, suggesting that in addition to PD-L1, other pathways may also be targeted by this approach. CONCLUSIONS: Our findings demonstrate a novel mechanism, ROS-induced down-regulation of miR-155-5p, by which tumors modulate the microenvironment that favors tumor growth. Understanding of the negative impact of ROS on the tumor immune response will improve current therapeutic strategies. Targeting miR-155-5p can be an alternative approach to prevent formation of an immunosuppressive TME through downregulation of PD-L1 and other immunosuppressive factors.

Redox sensitive miR-27a/b/Nrf2 signaling in Cr(VI)-induced carcinogenesis.

Hexavalent chromium [Cr(VI)] is a well-known carcinogen that can cause several types of cancer including lung cancer. NF-E2-related factor 2 (Nrf2), the redox sensitive transcription factor, can protect normal cells from a variety of toxicants and carcinogens by inducing the expression of cellular protective genes and maintaining redox balance. However, Nrf2 also protects cancer cells from radio- and chemo-therapies and facilitates cancer progression. Although Cr(VI) treatment has been demonstrated to upregulate Nrf2 expression, the mechanisms for Nrf2 regulation upon chronic Cr(VI) exposure remain to be elucidated. We found that Nrf2 was upregulated in BEAS-2B cells exposed to Cr(VI) from 1 to 5 months, and also in Cr(VI)-induced transformed (Cr-T) cells with Cr(VI) treatment for 6 months. We showed that KEAP1, the classic negative regulator of Nrf2, was downregulated after Cr(VI) exposure for 4 months, suggesting that Nrf2 induction by Cr(VI) treatment is through KEAP1 decrease at late stage. To further decipher the mechanisms of Nrf2 upregulation at early stage of Cr(VI) exposure, we demonstrated that miR-27a and miR-27b were redox sensitive miRNAs, since reactive oxygen species (ROS) scavengers induced miR-27a/b expression. After Cr(VI) exposure for 1 month, the expression levels of miR-27a/b was dramatically decreased. The changes of miR-27a/b and their target Nrf2 were confirmed in vivo by mouse model intranasally exposed to Cr(VI) for 12 weeks. Nrf2 was a direct target of miR-27a/b, which acted as tumor suppressors in vitro and in vivo to inhibit tumorigenesis and cancer development of Cr-T cells. The results suggested that the inhibition of miR-27a/b was responsible for Nrf2 upregulation at both early stage and late stage of Cr(VI) exposure. This novel regulation of Nrf2 upon chronic Cr(VI) exposure through redox-regulated miR-27a/b will provide potential targets for preventing and treating Cr(VI)-induced carcinogenesis in the future.

MiRNA-30e downregulation increases cancer cell proliferation, invasion and tumor growth through targeting RPS6KB1.

Human esophagus carcinoma (EC) is one of the most common malignant tumors, especially in Africa and Asia including China. In EC initiation and progression, genetic and epigenetic aberrations have been reported to play a major role, but the underlying molecular mechanisms are largely unknown. In this study, the miR-30e levels were analyzed in human EC tissues and TCGA databases, and the results demonstrated that miR-30e expression in EC tissues was significantly decreased compared to adjacent normal tissues. To further investigate the role of miR-30e in cancer cells, we found that forced expression of miR-30e dramatically inhibited cell proliferation, invasion, tube formation, and colony formation of cancer cells. To determine the underlying mechanism of miR-30e, we found that RPS6KB1 was a direct target of miR-30e by binding to its 3'-UTR, which was verified by luciferase activity assay using reporters with wild-type miR-30e and its seed sequence mutant constructs and Western blotting assay. In vivo experiment showed that miR-30e overexpression significantly inhibited tumor growth and decreased RPS6KB1 expression in xenografts. In EC, high expression of RPS6KB1 in tumor tissues indicated poor prognosis of patients with less survival rate. High levels of RPS6KB1 and low levels of miR-30e closely correlated poor survival of patients with several other types of cancer. These findings show that miR-30e and its target RPS6KB1 are important in cancer development and clinical outcomes, and miR-30e/RPS6KB1 is a potential future therapeutic pathway for EC intervention.

TBX15/miR-152/KIF2C pathway regulates breast cancer doxorubicin resistance via promoting PKM2 ubiquitination.

BACKGROUND: Chemoresistance is a critical risk problem for breast cancer treatment. However, mechanisms by which chemoresistance arises remains to be elucidated. The expression of T-box transcription factor 15 (TBX-15) was found downregulated in some cancer tissues. However, role and mechanism of TBX15 in breast cancer chemoresistance is unknown. Here we aimed to identify the effects and mechanisms of TBX15 in doxorubicin resistance in breast cancer. METHODS: As measures of Drug sensitivity analysis, MTT and IC50 assays were used in DOX-resistant breast cancer cells. ECAR and OCR assays were used to analyze the glycolysis level, while Immunoblotting and Immunofluorescence assays were used to analyze the autophagy levels in vitro. By using online prediction software, luciferase reporter assays, co-Immunoprecipitation, Western blotting analysis and experimental animals models, we further elucidated the mechanisms. RESULTS: We found TBX15 expression levels were decreased in Doxorubicin (DOX)-resistant breast cancer cells. Overexpression of TBX15 reversed the DOX resistance by inducing microRNA-152 (miR-152) expression. We found that KIF2C levels were highly expressed in DOX-resistant breast cancer tissues and cells, and KIF2C was a potential target of miR-152. TBX15 and miR-152 overexpression suppressed autophagy and glycolysis in breast cancer cells, while KIF2C overexpression reversed the process. Overexpression of KIF2C increased DOX resistance in cancer cells. Furthermore, KIF2C directly binds with PKM2 for inducing the DOX resistance. KIF2C can prevent the ubiquitination of PKM2 and increase its protein stability. In addition, we further identified that Domain-2 of KIF2C played a major role in the binding with PKM2 and preventing PKM2 ubiquitination, which enhanced DOX resistance by promoting autophagy and glycolysis. CONCLUSIONS: Our data identify a new mechanism by which TBX15 abolishes DOX chemoresistance in breast cancer, and suggest that TBX15/miR-152/KIF2C axis is a novel signaling pathway for mediating DOX resistance in breast cancer through regulating PKM2 ubiquitination and decreasing PKM2 stability. This finding suggests new therapeutic target and/or novel strategy development for cancer treatment to overcome drug resistance in the future.

Discovery of a New CDK4/6 and PI3K/AKT Multiple Kinase Inhibitor Aminoquinol for the Treatment of Hepatocellular Carcinoma.

Background: Hepatocellular carcinoma (HCC) is a lethal malignancy lacking effective treatment. The Cyclin-dependent kinases 4/6 (CDK4/6) and PI3K/AKT signal pathways play pivotal roles in carcinogenesis and are promising therapeutic targets for HCC. Here we identified a new CDK4/6 and PI3K/AKT multi-kinase inhibitor for the treatment of HCC. Methods: Using a repurposing and ensemble docking methodology, we screened a library of worldwide approved drugs to identify candidate CDK4/6 inhibitors. By MTT, apoptosis, and flow cytometry analysis, we investigated the effects of candidate drug in reducing cell-viability,inducing apoptosis, and causing cell-cycle arrest. The drug combination and thermal proteomic profiling (TPP) method were used to investigate whether the candidate drug produced antagonistic effect. The in vivo anti-cancer effect was performed in BALB/C nude mice subcutaneously xenografted with Huh7 cells. Results: We demonstrated for the first time that the anti-plasmodium drug aminoquinol is a new CDK4/6 and PI3K/AKT inhibitor. Aminoquinol significantly decreased cell viability, induced apoptosis, increased the percentage of cells in G1 phase. Drug combination screening indicated that aminoquinol could produce antagonistic effect with the PI3K inhibitor LY294002. TPP analysis confirmed that aminoquinol significantly stabilized CDK4, CDK6, PI3K and AKT proteins. Finally, in vivo study in Huh7 cells xenografted nude mice demonstrated that aminoquinol exhibited strong anti-tumor activity, comparable to that of the leading cancer drug 5-fluorouracil with the combination treatment showed the highest therapeutic effect. Conclusion: The present study indicates for the first time the discovery of a new CDK4/6 and PI3K/AKT multi-kinase inhibitor aminoquinol. It could be used alone or as a combination therapeutic strategy for the treatment of HCC.

Dysregulation of microRNAs in metal-induced angiogenesis and carcinogenesis.

MicroRNAs (miRNAs) are small endogenous non-coding RNAs that regulate cancer initiation, development, angiogenesis, and therapeutic resistance. Metal exposure widely occurs through air, water, soil, food, and industrial contaminants. Hundreds of millions of people may have metal exposure associated with toxicity, serious health problems, and cancer occurrence. Metal exposure is found to induce oxidative stress, DNA damage and repair, and activation of multiple signaling pathways. However, molecular mechanisms of metal-induced carcinogenesis remain to be elucidated. Recent studies demonstrated that the exposure of metals such as arsenic, hexavalent chromium, cadmium, and nickel caused dysregulation of microRNAs that are implicated to play an important role in cell transformation, tumor growth and angiogenesis. This review focuses on the recent studies that show metal-induced miRNA dysregulation and underlined mechanisms in cell malignant transformation, angiogenesis and tumor growth.

NOX4 Signaling Mediates Cancer Development and Therapeutic Resistance through HER3 in Ovarian Cancer Cells.

Development of resistance to therapy in ovarian cancer is a major hinderance for therapeutic efficacy; however, new mechanisms of the resistance remain to be elucidated. NADPH oxidase 4 (NOX4) is responsible for higher NADPH activity to increase reactive oxygen species (ROS) production. In this study, we showed that higher levels of NOX4 were detected in a large portion of human ovarian cancer samples. To understand the molecular mechanism of the NOX4 upregulation, we showed that NOX4 expression was induced by HIF-1α and growth factor such as IGF-1. Furthermore, our results indicated that NOX4 played a pivotal role in chemotherapy and radiotherapy resistance in ovarian cancer cells. We also demonstrated that NOX4 knockdown increased sensitivity of targeted therapy and radiotherapy through decreased expression of HER3 (ERBB3) and NF-κB p65. Taken together, we identified a new HIF-1α/NOX4 signal pathway which induced drug and radiation resistance in ovarian cancer. The finding may provide a new option to overcome the therapeutic resistance of ovarian cancer in the future.

Predictive significance of STK17A in patients with gastric cancer and association with gastric cancer cell proliferation and migration.

Gastric cancer (GC) is one of the most frequently diagnosed types of cancer worldwide, and exploring its potential therapeutic targets is particularly important for improving the prognosis of patients with GC. The aim of the present study was to investigate the association between serine/threonine kinase 17a (STK17A) expression and GC prognosis. STK17A expression was measured by quantitative real­time PCR, western blotting and immunohistochemical staining. Standard stable transfection technology was also used to construct overexpression and knockdown cell lines. Wound healing, Transwell, Cell Counting Kit­8 and colony formation assays, as well as other methods, were used to explore the function and underlying molecular mechanism of STK17A in GC. The results indicated that STK17A overexpression significantly promoted the proliferation and migration of GC cells. The clinical significance of STK17A in a cohort of 102 cases of GC was assessed by clinical correlation and Kaplan­Meier analyses. Overexpression of STK17A was demonstrated to be associated with tumor invasion depth (P<0.001), lymph node metastasis (P<0.001) and poor prognosis in terms of 5­year survival (P<0.001). In addition, Cox multivariate analysis revealed that STK17A expression was an independent risk factor for overall and progress­free survival (P<0.001). Therefore, STK17A may be a valuable biomarker for the prognosis of patients with GC.

Discovery of vanoxerine dihydrochloride as a CDK2/4/6 triple-inhibitor for the treatment of human hepatocellular carcinoma.

BACKGROUND: Cyclin-dependent kinases 2/4/6 (CDK2/4/6) play critical roles in cell cycle progression, and their deregulations are hallmarks of hepatocellular carcinoma (HCC). METHODS: We used the combination of computational and experimental approaches to discover a CDK2/4/6 triple-inhibitor from FDA approved small-molecule drugs for the treatment of HCC. RESULTS: We identified vanoxerine dihydrochloride as a new CDK2/4/6 inhibitor, and a strong cytotoxicdrugin human HCC QGY7703 and Huh7 cells (IC50: 3.79 µM for QGY7703and 4.04 µM for Huh7 cells). In QGY7703 and Huh7 cells, vanoxerine dihydrochloride treatment caused G1-arrest, induced apoptosis, and reduced the expressions of CDK2/4/6, cyclin D/E, retinoblastoma protein (Rb), as well as the phosphorylation of CDK2/4/6 and Rb. Drug combination study indicated that vanoxerine dihydrochloride and 5-Fu produced synergistic cytotoxicity in vitro in Huh7 cells. Finally, in vivo study in BALB/C nude mice subcutaneously xenografted with Huh7 cells, vanoxerine dihydrochloride (40 mg/kg, i.p.) injection for 21 days produced significant anti-tumor activity (p < 0.05), which was comparable to that achieved by 5-Fu (10 mg/kg, i.p.), with the combination treatment resulted in synergistic effect. Immunohistochemistry staining of the tumor tissues also revealed significantly reduced expressions of Rb and CDK2/4/6in vanoxerinedihydrochloride treatment group. CONCLUSIONS: The present study isthe first report identifying a new CDK2/4/6 triple inhibitor vanoxerine dihydrochloride, and demonstrated that this drug represents a novel therapeutic strategy for HCC treatment.