Growth Of Renal Cell Carcinoma Research Articles

SOX6 represses tumor growth of clear cell renal cell carcinoma by HMG domain-dependent regulation of Wnt/β-catenin signaling.

Sex-determining region Y box (SOXs) are expressed in various cells and control cell fate and differentiation in a multitude of physiologic processes. SOX6, a main representative of SOXs, is involved in the regulation of carcinogenesis in various human malignancies. However, the role of SOX6 in clear cell renal cell carcinoma (ccRCC) remains unclear. In this study, SOX6 expression in ccRCC and its clinical significance were investigated. In vitro and in vivo assays were used to explore the tumor-related function and the underlying molecular mechanism of SOX6 in ccRCC. We confirmed that SOX6 was frequently downregulated in ccRCC tissues and cell lines. Besides, downregulation of SOX6 was significantly associated with larger tumor sizes, advanced tumor stage, higher Fuhrman grades, and its expression could act as an independent prognostic factor for ccRCC (hazards ratio = 0.590, P = .026). Gain/loss-of-function experiments demonstrated that SOX6 could remarkably inhibit tumor cell growth and foci formation in vitro and xenograft tumorigenesis in vivo, respectively. Mechanistically, SOX6 could influence cell cycle by regulating the G1/the S phase transition and had an inhibitory effect on Wnt/β-catenin signaling as well as its target genes, c-Myc and cyclin D1. Interesting, the tumor-suppressive function of SOX6 was proved to be dependent on its specific high-mobility-group (HMG) domain. In general, our findings indicated that SOX6 was a novel tumor suppressor and prognostic biomarker in ccRCC. SOX6 could inhibit tumor growth by negatively regulating the Wnt/β-catenin signaling pathway in an HMG domain-dependent manner in ccRCC, which might provide a novel therapeutic approach for ccRCC.

Circ-SAR1A Promotes Renal Cell Carcinoma Progression Through miR-382/YBX1 Axis.

BackgroundAccumulating evidence points to a role for circular RNAs (circRNAs) in important regulatory function in tumor advancement. We explored the effect and function of circ-SAR1A in renal cell carcinoma (RCC).Methodscirc-SAR1A expression in RCC tissues and cell lines was explored by qRT-PCR. The roles of circ-SAR1A on RCC progression were explored by in vitro function assays. Moreover, we determined the underlying mechanism of circ-SAR1A in RCC progression through bioinformatics analysis and dual-luciferase reporter assays.ResultsOur data reveal that circ-SAR1A is significantly high in RCC tissues and cell lines. High circ-SAR1A levels are correlated to advanced Fuhrman grade, and lymph-node metastasis in RCC patients. Functional experiments indicate that circ-SAR1A suppression decreased RCC cell growth and invasion abilities in vitro. Mechanistically, circ-SAR1A upregulated YBX1 expression by sponging miR-382, resulting in promoting the growth and invasion in RCC cells.ConclusionOur data indicate that the circ-SAR1A/miR-382/YBX1 axis plays a critical role in RCC progression, which serve as a potential novel treatment strategy of RCC.

A Novel Combination Treatment with Honokiol and Rapamycin Effectively Restricts c-Met-Induced Growth of Renal Cancer Cells, and also Inhibits the Expression of Tumor Cell PD-L1 Involved in Immune Escape.

The mTOR inhibitor Rapamycin has tumor inhibitory properties; and it is also used as an immunosuppressive agent after organ transplantation. However, prolonged Rapamycin treatment re-activates Akt and can promote cancer growth. Honokiol is a natural compound with both anti-tumorigenic and anti-inflammatory properties. Here, we assessed the anti-tumor effects of Rapamycin and Honokiol combination in renal cell carcinoma (RCC). Receptor tyrosine kinase c-Met-mediated signaling plays a major role in RCC growth. We observed that compared with Rapamycin alone, Rapamycin + Honokiol combination can effectively down-regulate c-Met-induced Akt phosphorylation in renal cancer cells; and it markedly inhibited Ras activation and cell proliferation and promoted G1 phase cell cycle arrest. The combination treatment significantly induced ROS generation and cancer cell apoptosis even when c-Met is activated. Importantly, Honokiol, but not Rapamycin, decreased c-Met-induced expression of the co-inhibitory molecule PD-L1, implied in the immune escape of renal cancer cells. In mouse renal cancer cells and Balb/c splenocytes co-culture assay, Rapamycin + Honokiol markedly potentiated immune-cell-mediated killing of cancer cells, possibly through the down-regulation of PD-L1. Together, Honokiol can effectively overcome the limitation of Rapamycin treatment alone; and the combination treatment can markedly restrict the growth of RCC, with particular importance to post-transplantation renal cancer.

Inhibition of the CDK4/6-Cyclin D-Rb Pathway by Ribociclib Augments Chemotherapy and Immunotherapy in Renal Cell Carcinoma.

Renal cell carcinoma (RCC) is the most aggressive type of genitourinary cancer and is resistant to current therapies. Identifying drugs that enhance the efficacy of RCC standard-of-care drugs at sublethal concentrations is an alternative therapeutic strategy. Ribociclib is an orally available cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor that is approved for the treatment of breast cancer. In this work, we demonstrate that ribociclib at clinically achievable concentrations inhibits proliferation of 7 out of 9 tested RCC cell lines, with IC50 range from 76 to 280 nM. In addition, ribociclib induces apoptosis of RCC cells, but with less potency compared to its antiproliferative activity. The combination of ribociclib with chemotherapeutic or immunotherapeutic agents is synergistic in RCC cell lines. Of note, ribociclib demonstrates selective anti-RCC activity by sparing normal kidney cells and fibroblast cells. Consistent with the in vitro findings, ribociclib inhibits RCC growth at the dosage that does not lead to toxicity in mice and enhances the in vivo efficacy of RCC standard-of-care drugs. Mechanistically, we show that ribociclib remarkably inhibits phosphorylation of retinoblastoma protein (Rb) at various sites, leading to the suppression of transcription of E2F target genes in RCC cells. Our findings clearly demonstrate the potency and selectivity of ribociclib in RCC preclinical models, via inhibition of the CDK4/6-cyclin D/Rb pathway. Our findings support a clinical trial for the combination of ribociclib with chemo/immunotherapy in RCC.

Circular RNA circ_0001368 inhibited growth and invasion in renal cell carcinoma by sponging miR-492 and targeting LATS2

Circular RNAs (circRNAs) act as essential regulators in the tumorigenesis of renal cell carcinoma. Our study aims to investigate the underlying function and the molecular mechanisms of circ_0001368 in renal cell carcinoma. The qRT-PCR results indicate that the circ_0001368 expression level was downregulated in the carcinoma cells and tissues of the renal cell. circ_0001368 weakened cell proliferation and invasion in the ACHN and 786-O cells. The luciferase reporter assay showed that circ_0001368 functioned as an endogenous sponge for miR-492. The transwell and CCK8 assays showed that circ_0001368 suppressed cell proliferation and invasion in the ACHN and 786-O cells. Large tumor suppressor kinase 2 (LATS2) was confirmed by Targetscan as a target gene of miR-492. The overexpression of LATS2 repressed the growth and invasion of ACHN and 786-O cells. circ_0001368 upregulated the LATS2 expression and suppressed ACHN and 786-O cell growth and invasion by sponging miR-492. circ_0001368 suppressed the proliferation ability of 786-O in vivo. In conclusion, circ_0001368 was identified in this study as a novel anti-tumor RNA in renal cell carcinoma and can function as a potential therapeutic target for renal cell carcinoma treatment.

On the Shoulders of Giants: The Evolution of Renal Cell Carcinoma Treatment-Cytokines, Targeted Therapy, and Immunotherapy.

The treatment of advanced renal cell carcinoma (RCC) has evolved dramatically over the past 30 years, as has a better understanding of the biology of the disease, knowledge of multiple subtypes with distinct molecular abnormalities, and improved comprehension of the perturbed pathways that lead to the development and growth of RCC. This is no longer a monolithic disease, although the majority of tumors are of the clear cell subtype. However, progress is being made in other subtypes as well, as molecular profiles are better understood and as new agents show activity. Immunotherapies remain a major category of treatment, from cytokines to checkpoint inhibitors to ex vivo activated cellular therapy. Antiangiogenesis tyrosine kinase inhibitors are also an important part of the armamentarium. Because these approaches have evolved, we are now in the era of combination therapy using agents of differing mechanisms to try to achieve synergy to increase response rates and create durable responses leading to prolonged survival. Renal cell carcinoma as a tumor is unique in that there has always been a subset of patients who achieve complete responses that last for many years without subsequent treatment. Thus, the goal of further development is to enlarge this subset using new therapeutic approaches and to achieve further durable responses and treatment-free survival.

Circular RNA MYLK promotes tumour growth and metastasis via modulating miR-513a-5p/VEGFC signalling in renal cell carcinoma.

Growing evidence indicates that circular RNAs (circRNAs) are promising biomarkers, as they play significant roles in the development of various cancers. The circular RNA MYLK (circMYLK) has been reported to be involved in the development of malignant tumours, including liver, prostate and bladder cancers. Nevertheless, the biological function of circMYLK in renal cell carcinoma (RCC) remains unclear. In this study, we observed that circMYLK is notably up‐regulated in RCC. Increased circMYLK expression led to a larger tumour size, distant metastasis and poor prognosis of RCC patients. Moreover, circMYLK silencing repressed RCC growth and metastasis in vitro and in vivo. Mechanistically, circMYLK can capture miR‐513a‐5p to facilitate VEGFC expression and further promote the tumorigenesis of RCC cells. In summary, our findings demonstrate that circMYLK has an oncogenic role in RCC growth and metastasis by modulating miR‐513a‐5p/VEGFC signalling. Thus, circMYLK has potential as a diagnostic biomarker and therapeutic target in the treatment of RCC.

PD64-11 OVEREXPRESSION OF LNCRNA SUCLG2-AS1 INHIBITS CELL PROLIFERATION, MIGRATION AND INVASION THROUGH INHIBITING MAPK PATHWAY IN RENAL CELL CARCINOMA

You have accessJournal of UrologyKidney Cancer: Basic Research & Pathophysiology III (PD64)1 Apr 2020PD64-11 OVEREXPRESSION OF LNCRNA SUCLG2-AS1 INHIBITS CELL PROLIFERATION, MIGRATION AND INVASION THROUGH INHIBITING MAPK PATHWAY IN RENAL CELL CARCINOMA Zhang Kenan*, Gong Yanqing, Cai Lin, and Gong Kan Zhang Kenan*Zhang Kenan* More articles by this author , Gong YanqingGong Yanqing More articles by this author , Cai LinCai Lin More articles by this author , and Gong KanGong Kan More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000000981.011AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Pervious studies have revealed that long non-coding RNAs (lncRNAs) play an important role in renal cell carcinoma. However, the detailed roles of lncRNA SUCLG2-AS1 was rarely known and remained to be elucidated. METHODS: The genes of differential expression lncRNA were identified by TCGA.The relative expression level of SUCLG2-AS1 was determined by Real-Time qPCR in a total of 60 patients with clear cell renal cell carcinoma (ccRCC) and in different renal cell carcinoma (RCC) cell lines. Overexpression experiments were performed to investigate the biological roles of SUCLG2-AS1 on RCC cell proliferation, migration and invasion. Comprehensive transcriptional analysis, RNA-FISH and western blot were performed to explore the molecular mechanisms underlying the functions of SUCLG2-AS1. RESULTS: In this study, we found that SUCLG2-AS1 was downregulated in ccRCC tissues by analyzing TCGA online RNA-seq data. Moreover, decreased SUCLG2-AS1 expression level was positive associated with pathologic states and survival. Low expression of SUCLG2-AS1 was also confirmed in ccRCC tissues and RCC cell lines. In vitro, overexpression of SUCLG2-AS1 inhibits cell proliferation, migration and invasion in RCC cell lines. In a tumor xenograft model, we confirmed that SUCLG2-AS1 overexpression could significantly inhibit the growth of RCC. Mechanistically, we found that SUCLG2-AS1 was distributed mostly in the cytoplasm Furthermore, overexpression of SUCLG2-AS1 suppressed the expression of MAPK pathway related proteins in renal cell carcinoma. CONCLUSIONS: In conclusion, our findings demonstrated that SUCLG2-AS1 act as an suppressor gene in ccRCC, which may sever as a candidate prognostic biomarker for ccRCC patients. Source of Funding: This work was supported by the National Natural Science Foundation of China (grant 81572506), the Special Health Development Research Project of Capital (grant 2016-2-4074), and the Fundamental Research Funds for the Central Universities (grant BMU2018JI002). © 2020 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 203Issue Supplement 4April 2020Page: e1304-e1304 Advertisement Copyright & Permissions© 2020 by American Urological Association Education and Research, Inc.MetricsAuthor Information Zhang Kenan* More articles by this author Gong Yanqing More articles by this author Cai Lin More articles by this author Gong Kan More articles by this author Expand All Advertisement PDF downloadLoading ...

OTUB1-mediated deubiquitination of FOXM1 up-regulates ECT-2 to promote tumor progression in renal cell carcinoma

BackgroundOTUB1 (ovarian tumor domain protease domain-containing ubiquitin aldehyde-binding proteins)-mediated deubiquitination of FOXM1 (Forkhead box M1) participates in carcinogenesis of various tumors. We aim to investigate the effect and mechanism of OTUB1/FOXM1 on RCC (renal cell carcinoma) progression. Expression levels of OTUB1 in RCC tissues and cell lines were examined by qRT-PCR (quantitative real-time polymerase chain reaction) and immunohistochemistry. Cell proliferation was measured with CCK8 (Cell Counting Kit-8) and colony formation assays. Wound healing and transwell assays were used to determine cell migration and invasion, respectively. The effect of OTUB1 on FOXM1 ubiquitination was examined by Immunoprecipitation. Western blot was used to uncover the underlying mechanism. In vivo subcutaneous xenotransplanted tumor model combined with immunohistochemistry and western blot were used to examine the tumorigenic function of OTUB1.ResultsOTUB1 was up-regulated in RCC tissues and cell lines, and was associated with poor prognosis of RCC patients. Knockdown of OTUB1 inhibited cell viability and proliferation, as well as migration and invasion of RCC cells. Mechanistically, knockdown of OTUB1 down-regulated FOXM1 expression by promoting its ubiquitination. Down-regulation of FOXM1 inhibited ECT2 (epithelial cell transforming 2)-mediated Rho signaling. Moreover, the inhibition of RCC progression caused by OTUB1 knockdown was reversed by FOXM1 over-expression. In vivo subcutaneous xenotransplanted tumor model also revealed that knockdown of OTUB1 could suppress in vivo RCC growth via down-regulation of FOXM1-mediated ECT2 expression.ConclusionsOTUB1-mediated deubiquitination of FOXM1 up-regulates ECT-2 to promote tumor progression in RCC, providing a new potential therapeutic target for RCC treatment.

NKAP promotes renal cell carcinoma growth via AKT/mTOR signalling pathway.

Renal cell carcinoma (RCC) is the seventh most common site for malignant tumours worldwide leading to a high risk of death. NKAP is a conserved nuclear protein that has critical roles in the development, maturation, and functional acquisition of T cells, iNKT cells, and cancers. But the function and underlying mechanism of NKAP in RCC is still unknown. Knockdown of NKAP by siRNA interference (siNKAP) was used to explore the roles of NAKP in human RCC cells. Here, we found that siNKAP strongly inhibited the proliferation and motility of Ketr-3 and 786-0 cells and induced cell apoptosis. Furthermore, the expression of anti-apoptotic protein Bcl2 in the siNKAP group was strongly decreased, while the expression of pro-apoptotic proteins Bax, cleaved Caspase-3, and cleaved Caspase-9 was significantly increased. Finally, to identify the potential mechanisms, we detected related proteins of the AKT/mTOR signalling pathway by western blot assay. We found that siNKAP significantly inhibited the expression of cyclin D1 and the phosphorylation of AKT and mTOR. The findings for the first time reveal that the AKT/mTOR signalling pathway is involved in the oncogenic role of NKAP in RCC, which provides an important basis for exploring the molecular regulation mechanism of RCC. SIGNIFICANCE OF THE STUDY: There is an urgent need to study the molecular mechanisms involved in RCC to promote the development of early diagnosis and more effective treatment options. This research provides an important basis for exploring the accurate regulatory mechanism of NKAP in RCC and a novel perspective to find the potential utility of NKAP inhibitors for RCC therapy.

Noncoding RNAs orchestrate cell growth, death and drug resistance in renal cell carcinoma.

Aim: We aimed to explore the roles of noncoding RNAs (ncRNAs) in renal cell carcinoma. Materials & methods: The altered expressions of miR-196a2, miR-499a, H19, MALAT1and GAS5, as well as some target transcripts were identified by quantitative real-time reverse transcription polymerase chain reaction. Results: Up-regulation of miR-196a2, E2F3, HSPA4and MALAT1 (median fold change: 5.69, 25.6, 4.15 and 19.6, respectively) and down-regulation of miR-499a, GAS5, PDCD4, ANXA1and DFFA (median fold change: 0.28, 0.25, 0.12, 0.09 and 0.08, respectively) were reported compared with paired non-cancer tissue. PDCD4, DFFA and GAS5 down-regulation was associated with poor prognosis in terms of high grade, larger tumor, nodal invasion, capsular and pelvic infiltration. Conclusion: The identified ncRNAs could represent potential theranostic biomarkers for renal cell carcinoma.

Inactivation of the AMPK-GATA3-ECHS1 Pathway Induces Fatty Acid Synthesis That Promotes Clear Cell Renal Cell Carcinoma Growth.

The tumorigenic role and underlying mechanisms of lipid accumulation, commonly observed in many cancers, remain insufficiently understood. In this study, we identified an AMP-activated protein kinase (AMPK)-GATA-binding protein 3 (GATA3)-enoyl-CoA hydratase short-chain 1 (ECHS1) pathway that induces lipid accumulation and promotes cell proliferation in clear cell renal cell carcinoma (ccRCC). Decreased expression of ECHS1, which is responsible for inactivation of fatty acid (FA) oxidation and activation of de novo FA synthesis, positively associated with ccRCC progression and predicted poor patient survival. Mechanistically, ECHS1 downregulation induced FA and branched-chain amino acid (BCAA) accumulation, which inhibited AMPK-promoted expression of GATA3, a transcriptional activator of ECHS1. BCAA accumulation induced activation of mTORC1 and de novo FA synthesis, and promoted cell proliferation. Furthermore, GATA3 expression phenocopied ECHS1 in predicting ccRCC progression and patient survival. The AMPK-GATA3-ECHS1 pathway may offer new therapeutic approaches and prognostic assessment for ccRCC in the clinic. SIGNIFICANCE: These findings uncover molecular mechanisms underlying lipid accumulation in ccRCC, suggesting the AMPK-GATA3-ECHS1 pathway as a potential therapeutic target and prognostic biomarker.

PRMT7 promotes the growth of renal cell carcinoma through modulating the β-catenin/C-MYC axis.

Arginine methylation is mainly catalyzed by protein arginine methyltransferases (PRMTs) and is one of the most common posttranslational modifications closely related to the development of cancer. PRMT7 is overexpressed in various tumors and promotes the malignant progression of tumors, but the expression and role of PRMT7 in renal cell carcinoma (RCC) remains unclear. Here, we report for the first time that the expression of PRMT7 is increased in clear cell renal cell carcinoma (ccRCC) tissues and that it may act as an independent predictor for the poor prognosis of ccRCC patients. We found that PRMT7 promotes RCC cell proliferation both in vitro and in vivo. Moreover, the methyltransferase inhibitor adenosine dialdehyde (Adox) blocks the action of PRMT7 in ccRCC cells. Furthermore, PRMT7 regulates the expression of C-MYC, which plays an important role in promoting ccRCC cell proliferation, and it accelerates the tumor development of RCC in a C-MYC-dependent manner. Mechanistically, PRMT7 upregulates the expression of C-MYC via methylating β-catenin and inhibiting the ubiquitin-mediated degradation of β-catenin. In conclusion, our study demonstrates that overexpressed PRMT7 in ccRCC cells acts as an oncogene to promote the growth of renal cell carcinoma through regulating the β-catenin/C-MYC axis, thereby providing new strategies and targets for the treatment of ccRCC patients.

SH3BGRL2 inhibits growth and metastasis in clear cell renal cell carcinoma via activating hippo/TEAD1-Twist1 pathway.

BackgroundClear cell renal cell carcinoma (ccRCC) is one of the most prevalent malignancies in the world, and tumor metastasis is still the main reason for disease progression. Accumulating evidence shows that SH3BGRL2 may play a key role in tumor progression and metastasis. However, the role of SH3BGRL2 in ccRCC has not been systematically investigated and remains elusive.MethodsThe clinical significance of SH3BGRL2 was evaluated by bioinformatic analysis and tissue microarray (TMA) samples. SH3BGRL2 expression was determined by RT-PCR, western blot and immunohistochemistry staining. Tumor suppressive effect of SH3BGRL2 was determined by both in vitro and in vivo studies. Western blot, chromatin immunoprecipitation assay and luciferase report assay were applied for mechanism dissection.FindingsSH3BGRL2 was crucial for epithelial-mesenchymal transition (EMT) progression and metastasis in ccRCC. Clinically, SH3BGRL2 was identified as an independent prognostic factor for ccRCC patients. Gain- and loss-of-function results suggested that SH3BGRL2 played a critical role in cell proliferation, migration and invasion. Mechanistically, we found that SH3BGRL2 acted as a tumor suppressor through Hippo/TEAD1 signaling, then TEAD1 altered Twist1 expression at the transcriptional level via directly binding to its promoter region.InterpretationOur findings established that SH3BGRL2 performed as a tumor suppressor and modulator via Hippo/TEAD1-Twist1 signaling in ccRCC, and the alteration of SH3BGRL2 could serve as a functional response biomarker of tumor progression and metastasis in ccRCC.

Poly(U) binding splicing factor 60 promotes renal cell carcinoma growth by transcriptionally upregulating telomerase reverse transcriptase.

Background: Abnormal transcriptional upregulation of telomerase reverse transcriptase (TERT) plays a dominant role in telomerase activation in various cancers. TERT promoter mutations (TPMs) have been identified as a key mechanism in TERT upregulation. However, the mechanism of TERT upregulation in cancers with low frequency of TPMs are not fully elucidated so far.Methods: The expression of PUF60 and TERT was detected by real-time PCR, western blot and immunohistochemistry. TERT promoter binding proteins were identified by streptavidin-agarose pulldown assay and mass spectrum (MS) analysis. The role of PUF60/TERT in renal cancer was evaluated on cell growth in vitro and in vivo.Results: In this study, we identify the regulation mechanism of TERT in renal cell carcinoma (RCC) cells which have rare TPMs but exert significant upregulation of TERT. We found that TERT was highly expressed in RCC tumor tissues, and elevated TERT expression was associated with poor prognosis for patients. We also detected the relatively rare TPM status in both RCC tumor tissues and RCC cell lines. Mechanistically, PUF60, a RNA binding protein, was identified as a novel TERT regulator which bound to the TERT and transcriptionally upregulated TERT expression in RCC cells. The in vitro and in vivo experiments also demonstrated that PUF60 could promote RCC cell growth through activation of TERT expression in a TPM status independent way. Furthermore, we showed that there was a strong correlation of the expression of PUF60 and TERT in RCC tumor tissues and RCC cell lines, and the patients with high expression of PUF60 and TERT had significantly shorter survival.Conclusions: Collectively, these results indicated that PUF60 transcriptionally upregulated TERT expression to promote RCC growth and progression in a TPM status independent way, suggesting that the PUF60/TERT signaling pathway may serve as potential prognostic biomarkers and therapeutic targets for RCC.

LncRNA-LET inhibits cell growth of clear cell renal cell carcinoma by regulating miR-373-3p

BackgroundClear cell renal cell carcinoma (ccRCC) is the most common renal cell carcinoma subtype with a poor prognosis. LncRNA-LET is a long non-coding RNA (lncRNA) that is down-regulated in ccRCC tissues. However, its role in ccRCC development and progress is unclear.MethodsLncRNA-LET expression was detected in ccRCC tissues and ccRCC cells using quantitative real-time PCR. The overexpression and knockdown experiments were performed in ccRCC cells and xenograft mouse model to evaluate role of lncRNA-LET. Cell cycle, apoptosis and JC-1 assays were conducted via flow cytometer. The protein levels were measured through western blot analysis and the interaction between lncRNA-LET and miR-373-3p was identified via luciferase reporter assay.ResultsLncRNA-LET expression was lower in ccRCC tissues than that in the matched adjacent non-tumor tissues (n = 16). In vitro, lncRNA-LET overexpression induced cell cycle arrest, promoted apoptosis and impaired mitochondrial membrane potential, whereas its knockdown exerted opposite effects. Moreover, we noted that lncRNA-LET may act as a target for oncomiR miR-373-3p. In contrast to lncRNA-LET, miR-373-3p expression was higher in ccRCC tissues. The binding between lncRNA-LET and miR-373-3p was validated. Two downstream targets of miR-373-3p, Dickkopf-1 (DKK1) and tissue inhibitor of metalloproteinase-2 (TIMP2), were positively regulated by lncRNA-LET in ccRCC cells. MiR-373-3p mimics reduced lncRNA-LET-induced up-regulation of DKK1 and TIMP2 levels, and attenuated lncRNA-LET-mediated anti-tumor effects in ccRCC cells. In vivo, lncRNA-LET suppressed the growth of ccRCC xenograft tumors.ConclusionThese findings indicate that lncRNA-LET plays a tumor suppressive role in ccRCC by regulating miR-373-3p.

CircRNA cRAPGEF5 inhibits the growth and metastasis of renal cell carcinoma via the miR-27a-3p/TXNIP pathway.

Circular RNAs (circRNAs) are reported to act as important regulators in cancers. CircRNA RAPGEF5 (cRAPGEF5) is derived from exons 2-6 of the RAPGEF5 gene and may promote papillary thyroid cancer progression. However, the role of cRAPGEF5 in renal cell carcinoma (RCC) remains unclear. In this study, we found cRAPGEF5 to be significantly downregulated in RCC tissues. Among 245 RCC cases, cRAPGEF5 downregulation correlated positively with aggressive clinical characteristics and independently predicted poor overall survival and recurrence-free survival. Functional assays demonstrated that cRAPGEF5 suppresses RCC proliferation and migration in vitro and in vivo. Mechanistically, RNA Immunoprecipitation and circRNA in vivo precipitation assays showed that cRAPGEF5 functions as a sponge of oncogenic miR-27a-3p, which targets the suppressor gene TXNIP. Interactions between miR-27a-3p and cRAPGEF5 or TXNIP were confirmed by dual-luciferase reporter assays. In conclusion, cRAPGEF5 plays a role in suppressing RCC via the miR-27a-3p/TXNIP pathway and may serve as a promising prognostic biomarker and novel therapeutic target for RCC patients.

Cytochrome C inhibits tumor growth and predicts favorable prognosis in clear cell renal cell carcinoma.

Cytochrome C (Cyto C), a multifunctional enzyme, has been demonstrated to be associated with cell apoptosis and respiration. Accumulating evidence has revealed that serum Cyto C is an effective indicator in evaluating the effect of chemotherapy. However, to the best of our knowledge, the clinical significance of Cyto C and its role in cell growth and apoptosis in clear cell renal cell carcinoma (CCRCC) remain unknown. In the present study, Cyto C expression was detected in 150 CCRCC and 30 normal tissues samples via immunohistochemistry. The results demonstrated that Cyto C protein expression levels in CCRCC tissues were downregulated compared with those in corresponding normal tissues. In addition, it was revealed that Cyto C expression was negatively associated with TNM stage. Further analyses revealed that patients with CCRCC and low Cyto C expression levels had a shorter survival time than those with high Cyto C expression. Multivariate analyses indicated that high Cyto C expression levels were an independent prognostic factor for survival. Functionally, overexpression of Cyto C effectively suppressed the growth of CCRCC cells and induced cell apoptosis, and knockdown of Cyto C reversed these effects. Finally, overexpression of Cyto C inhibited the tumor growth of CCRCC cells in vivo. Overall, the data of the present study indicated that Cyto C may be a novel prognostic biomarker and acted as a regulator of tumor growth in CCRCC.

SPTLC1 inhibits cell growth via modulating Akt/FOXO1 pathway in renal cell carcinoma cells

Serine palmitoyltransferase long chain-1 (SPTLC1), which is the rate-limiting enzyme for sphingolipid biosynthesis, has been indicated to be essential for carcinoma cell survival and proliferation in recent, but its role in the regulation of renal cell carcinoma (RCC) remains unknown. In the present study, we found that SPTLC1 expression was significantly decreased in RCC tissues compared to non-tumor tissues, and low SPTLC1 expression was associated with poor overall survival of RCC patients. In addition, our results revealed that forced expression of SPTLC1 could significantly inhibit cell growth in vitro and in vivo via, at least in part, modulating Akt/FOXO1 signaling pathway, thus representing a novel role of SPTLC1 in the regulation of tumor growth in RCC for the first time.

MiRNA‑205‑5p functions as a tumor suppressor by negatively regulating VEGFA and PI3K/Akt/mTOR signaling in renal carcinoma cells.

MicroRNAs (miRNAs) are involved in the development of various types of cancers. Dysregulation of miR-205-5p has been reported in various types of human cancer. However, little is known concerning the role of miR-205-5p in renal cell carcinoma (RCC). The pr~esent study was designed to investigate the role of miR-205-5p in RCC. The expression of miR-205-5p was measured in clear cell renal cell carcinoma (ccRCC) tissues and cell lines using RT-qPCR. RCC cell lines were transfected with miR-205-5p mimics. CCK-8 assays, wound healing assays, Matrigel invasion assays and nucleosome ELISAs were used to assess the effects of miR-205-5p on cell growth, migration, invasion and apoptosis, respectively. Western blotting was employed to detect changes in protein levels. Bioinformatic analyses and luciferase reporter assays were performed to identify the potential targets of miR-205-5p. Mouse xenograft models were used to verify the effect of miR-205-5p in vivo. The expression of miR-205-5p was found to be downregulated in 25 RCC tissues compared to that noted in the adjacent normal tissues. Decreased expression of miR-205-5p was associated with poor clinical outcomes. Based on the results of the in vitro experiments, overexpression of miR-205-5p reduced RCC cell proliferation, invasion and migration. Overexpression of miR-205-5p also promoted apoptosis and inhibited the EMT in RCC cells. Moreover, the PI3K/Akt signaling pathway was found to be negatively regulated by miR-205-5p. Bioinformatic analyses and luciferase reporter assays revealed that miR-205-5p directly targeted the 3′-UTR of vascular endothelial growth factor A (VEGFA). Furthermore, miR-205-5p negatively regulated the expression of VEGFA in ccRCC cell lines. In ccRCC tissues, miR-205-5p expression was inversely correlated with VEGFA expression. Moreover, overexpression of miR-205-5p inhibited RCC growth in vivo in a mouse xenograft model. Overall, miR-205-5p functions as a tumor suppressor in RCC by targeting VEGFA and the PI3K/Akt signaling pathway, providing a potential therapeutic target for the treatment of ccRCC.