Inhibited Renal Cell Carcinoma Cell Proliferation Research Articles

Syringin as a novel therapeutic agent for renal cell carcinoma by targeting EGFR/PI3K/Akt pathway and enhancing sunitinib efficacy

Syringin as a novel therapeutic agent for renal cell carcinoma by targeting EGFR/PI3K/Akt pathway and enhancing sunitinib efficacy

METTL3 and IGF2BP1-Mediated m6A Modification of ZHX2 Promotes Tumor Property of Renal Cell Carcinoma

Introduction: Renal cell carcinoma (RCC) is a common type of kidney cancer with limited treatment options and a high mortality rate. Therefore, it is essential to understand the role and mechanism of key genes in RCC development and progression. This study aimed to analyze the role of zinc fingers and homeoboxes 2 (ZHX2) in RCC and the underlying mechanism. Methods: RNA expression was analyzed by quantitative real-time polymerase chain reaction, while protein expression was analyzed by Western blotting assay and immunohistochemistry assay. Cell viability was evaluated using CCK-8 assay, and cell proliferation was assessed by EdU assay. The rate of cell apoptosis was quantified by flow cytometry. Transwell assays were conducted to analyze cell migration and invasion. The sphere formation assay was performed to assess the formation of microspheres. Additionally, m6A RNA immunoprecipitation assay and RNA immunoprecipitation assay were utilized to investigate the relationship between ZHX2 and two proteins, methyltransferase like 3 (METTL3) and insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1). The stability of ZHX2 mRNA was analyzed through the Actinomycin D assay. Furthermore, a xenograft mouse model assay was conducted to analyze the effect of ZHX2 overexpression and METTL3 silencing on RCC cell tumor properties in vivo. Results: ZHX2 expression was upregulated in both RCC tissues and cells when compared with healthy renal tissues and human renal cortex proximal convoluted tubule epithelial cells. Depletion of ZHX2 inhibited RCC cell proliferation, migration, invasion, and spheroid-forming capacity but promoted cell apoptosis. Moreover, it was found that METTL3-mediated m6A methylation of ZHX2 and IGF2BP1 also stabilized ZHX2 through m6A methylation modification. Furthermore, ZHX2 overexpression showed a potential for attenuating the effects induced by METTL3 silencing and counteracted the inhibitory effect of METTL3 depletion on tumor formation in vivo. Conclusion: METTL3 and IGF2BP1-mediated m6A modification of ZHX2 promoted RCC progression. The finding suggests that ZHX2 may serve as a potential therapeutic target in RCC, providing valuable insights for future clinical interventions.

CALCR exacerbates renal cell carcinoma progression via stabilizing CD44.

The calcitonin receptor (CALCR) is an essential protein for maintaining calcium homeostasis and has been reported to be upregulated in numerous cancers. However, the molecular role of CALCR in renal cell carcinoma (RCC) is not well understood. In this study, we identified the overexpression of CALCR in RCC using human tissue chip by immunohistochemical (IHC) staining, which was associated with a poor prognosis. Functionally, CALCR depletion inhibited RCC cell proliferation and migration, and induced cell apoptosis and cycle arrest. CALCR is also essential for in vivo tumor formation. Mechanistically, we demonstrated that CALCR could directly bind to CD44, preventing CD44 protein degradation and thereby upregulating CD44 expression. Moreover, a deficiency in CD44 significantly attenuated the promoting role of CALCR on RCC cell proliferation, migration and anti-apoptosis capacities. Collectively, CALCR exacerbates RCC progression via stabilizing CD44, offering a fundamental basis for considering CALCR as a potential therapeutic target for RCC patients.

CircSCNN1A inhibits the proliferation, migration and invasion of renal cell carcinoma cells by decreasing CLDN8 expression through miR-590-5p.

Increasing evidence suggests that circular RNA (circRNA) plays a regulatory role in the progression of renal cell carcinoma (RCC). However, the precise function and underlying mechanism of circSCNN1A in RCC progression still remain unclear. The expression levels of circSCNN1A, microRNA-590-5p (miR-590-5p), claudin 8 (CLDN8), cyclin D1, matrix metalloprotein 2 (MMP2), MMP9, E-cadherin, N-cadherin and vimentin were detected by a quantitative real-time polymerase chain reaction and Western blotting analysis. Immunohistochemistry assay was performed to analyze the positive expression rate of CLDN8. Cell proliferation was investigated by cell colony formation, 5-Ethynyl-2'-deoxyuridine and DNA content quantitation assays. Cell migration and invasion were assessed by wound-healing and transwell invasion assays. Interactions among circSCNN1A, miR-590-5p and CLDN8 were identified by dual-luciferase reporter assay, RNA immunoprecipitation assay and RNA pull-down assay. Xenograft mouse model assay was conducted to verify the effect of circSCNN1A on tumor formation in vivo. CircSCNN1A and CLDN8 expression were significantly downregulated, while miR-590-5p was upregulated in both RCC tissues and cells. CircSCNN1A overexpression inhibited RCC cell proliferation, migration and invasion, accompanied by decreases of cyclin D1, MMP2, MMP9, N-cadherin and vimentin expression and an increase of E-cadherin expression. CircSCNN1A acted as a miR-590-5p sponge and regulated RCC cell processes by binding to miR-590-5p. CLDN8, a target gene of miR-590-5p, was involved in the regulation of the biological behaviors of RCC cells by miR-590-5p. In addition, circSCNN1A induced CLDN8 production by interacting with miR-590-5p. Further, circSCNN1A suppressed tumor formation in vivo. CircSCNN1A inhibited RCC cell proliferation, migration and invasion by regulating the miR-590-5p/CLDN8 pathway.

Calcium saccharate/DUSP6 suppresses renal cell carcinoma glycolytic metabolism and boosts sunitinib efficacy via the ERK-AKT pathway

Current therapeutic options for renal cell carcinoma (RCC) are very limited, which is largely due to inadequate comprehension of molecular pathological mechanisms as well as RCC's resistance to chemotherapy. Dual-specificity phosphatase 6 (DUSP6) has been associated with numerous human diseases. However, its role in RCC is not well understood. Here, we show that diminished DUSP6 expression is linked to RCC progression and unfavorable prognosis. Mechanistically, DUSP6 serves as a tumor suppressor in RCC by intervening the TAF10 and BSCL2 via the ERK-AKT pathway. Further, DUSP6 is also transcriptionally regulated by HNF-4a. Moreover, docking experiments have indicated that DUSP6 expression is enhanced when bound by Calcium saccharate, which also inhibits RCC cell proliferation, metabolic rewiring, and sunitinib resistance. In conclusion, our study identifies Calcium saccharate as a prospective pharmacological therapeutic approach for RCC.

AURKA promotes renal cell carcinoma progression via regulation of CCNB1 transcription

AURKA is a member of the serine/threonine kinase family and its kinase activity is crucial for the progression of mitosis. Recent studies have highlighted the therapeutic significance of AURKA inhibition in multiple cancer types. However, the specific mechanisms by which AURKA contributes to the progression of renal cell carcinoma (RCC) have not been fully elucidated. In this study, AURKA expression level was identified in human RCC tissues by immunohistochemical (IHC) staining. The function of AURKA on cell malignant phenotypes was evaluated in vitro after AURKA inhibition. The subcutaneous xenograft was conducted to confirm the in vivo effect of AURKA knockdown on growth of RCC cells. Finally, Co-IP, luciferase assay and ChIP experiments were performed to reveal the regulatory mechanism of AURKA on CCNB1. Our results showed a significant upregulation of AURKA in RCC tissues and cell lines, and a high AURKA expression was associated with poor prognosis. AURKA knockdown inhibited RCC cell proliferation and migration, induced cell apoptosis, and led to G1/G2 phase arrest. This effect was further confirmed by the use of an AURKA inhibitor. Mechanistically, AURKA interacted with E2F1, and subsequently recruited it to the promoter region of CCNB1. CCNB1 expression was essential for AURKA-induced RCC progression. Collectively, our results suggested that AURKA plays an important role in development of RCC via regulating CCNB1 transcription.

CircPDSS1 accelerates malignant progression of renal cell carcinoma through sponging of miR-182-5p

Purpose: To investigate the biological function and mechanisms of circPDSS1 in triggering malignant progression of renal cell carcinoma (RCC).
 Methods: Quantitative real-time polymerase chain reaction (qRT-PCR) was conducted to determine circPDSS1 levels in 50 pairs of RCC and para-cancerous tissues. The relationship between circPDSS1 level and pathological indices in RCC patients was analyzed, while the in vitro effect of circPDSS1 in regulating RCC proliferation was assessed using cell counting kit-8 (CCK-8), colony formation and 5- ethynyl-2’- deoxyuridine (EdU) assay. The sponge effect of circPDSS1 on miR-182-5p was examined by bioinformatics analysis and dual- luciferase reporter assay, while their involvement in mediating malignant progression of RCC was analyzed using rescue experiments. In vivo, the influence of circPDSS1 on RCC growth was determined by establishing a xenograft model in nude mice. Thereafter, RCC tissues were harvested from mice to assess relative levels of miR-182-5p and Ki-67.
 Results: CircPDSS1 was highly expressed in RCC tissues (p < 0.05). A high level of circPDSS1 correlated with advanced tumor staging and low overall survival. Knockdown of circPDSS1 inhibited RCC cell proliferation, and CircPDSS1 sponged and negatively regulated miR-182-5p (p < 0.05). MiR182-5p was able to abolish regulatory effect of circPDSS1 on malignant proliferative potential in RCC cells. In nude mice bearing RCC, in vivo knockdown of circPDSS1 slowed down tumor growth and decreased positive expression of Ki-67 in tumor tissues (p < 0.05).
 Conclusion: CircPDSS1 predicts tumor stage and prognosis in RCC patients. It triggers malignant progression of RCC through sponging of miR-182-5p.

Brusatol enhances MEF2A expression to inhibit RCC progression through the Wnt signalling pathway in renal cell carcinoma.

Renal cell carcinoma (RCC) is the most aggressive subtype of kidney tumour with a poor prognosis and an increasing incidence rate worldwide. Brusatol, an essential active ingredient derived from Brucea javanica, exhibits potent antitumour properties. Our study aims to explore a novel treatment strategy for RCC patients. We predicted 37 molecular targets of brusatol based on the structure of brusatol, and MEF2A (Myocyte Enhancer Factor 2A) was selected as our object through bioinformatic analyses. We employed various experimental techniques, including RT-PCR, western blot, CCK8, colony formation, immunofluorescence, wound healing, flow cytometry, Transwell assays and xenograft mouse models, to investigate the impact of MEF2A on RCC. MEF2A expression was found to be reduced in patients with RCC, indicating a close correlation with MEF2A deubiquitylation. Additionally, the protective effects of brusatol on MEF2A were observed. The overexpression of MEF2A inhibits RCC cell proliferation, invasion and migration. In xenograft mice, MEF2A overexpression in RCC cells led to reduced tumour size compared to the control group. The underlying mechanism involves the inhibition of RCC cell proliferation, invasion, migration and epithelial-mesenchymal transition (EMT) through the modulation of Wnt/β-catenin signalling. Altogether, we found that MEF2A overexpression inhibits RCC progression by Wnt/β-catenin signalling, providing novel insight into diagnosis, treatment and prognosis for RCC patients.

Hyperthermia inhibits cellular function and induces immunogenic cell death in renal cell carcinoma

BackgroundIn recent years, hyperthermia has been widely applied as a novel strategy for cancer treatment due to its multiple antitumour effects. In particular, the potential influences of hyperthermia on the tumour immune microenvironment may improve the efficacy of immunotherapies. However, the effect of hyperthermia on renal cell carcinoma (RCC) has not been well characterized until now.MethodsIn the present study, we primarily evaluated the effects of hyperthermia on cellular function via cellular proliferation, migration, invasion and apoptosis assays. In addition, the influence of hyperthermia on the immunogenicity of RCC cells was analysed using flow cytometry analysis, enzyme-linked immunosorbent assays, and immunofluorescent (IF) staining.ResultsOur results demonstrate that hyperthermia significantly inhibits RCC cell proliferation, migration, and invasion and promotes cell apoptosis. In addition, we verified that hyperthermia improves the immunogenicity of RCC cells by inducing immunogenic cell death.ConclusionOur findings suggest that hyperthermia is a promising therapeutic strategy for RCC.

Polymer nanoparticle delivery of microRNA-1303 suppresses renal cell carcinoma differentiation via regulation of small nucleolar RNA host gene 16

Small nucleolar RNA host gene 16 (SNHG16) participates in some cancers as microRNA (miR)-1303 is also reported to function on proliferation of various cancer cells. This study aimed to assess SNHG16 and miR-1303′s role in renal cell carcinoma (RCC) and its underlying mechanism. RT-qPCR was used to determine SNHG16 and miR-1303 expression in RCC cells (A498, 786-O, ACHN and OS-RC-2) and normal kidney epithelial cells (HK-2). Functional experiment was established to detect the role of miR-1303. After synthesis of nanoparticles carrying miR-1303 and transfection, CCK-8 method and assays were used to evaluate cell growth and apoptosis. The target genes for miR-1303 were predicted using bioinformatics software, and binding of miR-1303 to SNHG16 was evaluated using the dual-luciferase reporter assay. miR-1303 was lowly expressed in RCC cells, with lowest level in A498 (p < 0.05). Overexpressed miR-1303 significantly reduced proliferation ability of RCC cells and induced apoptosis (p < 0.05). Besides, transfection of NP carrying miR-1303 mimic resulted in dramatically decreased migrated cells when reducing the expression of SNHG18 mRNA. The presence of NPs strengthened the inhibitory effect of miR-1303 on RCC. Furthermore, the miR-1303+SNHG16-WT co-transfection group had lower relative luciferase activity compared with miR-1303+SNHG16-MUT co-transfection group (p < 0.05). miR-1303 was down-regulated in RCC and NP delivery of miR-1303 inhibited RCC cell proliferation and differentiation through regulation of SNHG16. These findings suggest miR-1303 may become a potential molecular target for RCC.

KMT2B promotes the growth of renal cell carcinoma via upregulation of SNHG12 expression and promotion of CEP55 transcription

BackgroundThis study aims to clarify the mechanistic action of long non-coding RNA (lncRNA) SNHG12 in the development of renal cell carcinoma (RCC), which may be associated with promoter methylation modification by KMT2B and the regulation of the E2F1/CEP55 axis.MethodsTCGA and GEO databases were used to predict the involvement of SNHG12 in RCC. Knockdown of SNHG12/E2F1/CEP55 was performed. Next, SNHG12 expression and other mRNAs were quantified by RT-qPCR. Subsequently, CCK-8 was used to detect cell proliferation. Wound healing assay and Transwell assay were used to detect cell migration and invasion, respectively. The in vitro angiogenesis of human umbilical vein endothelial cells (HUVECs) was explored by matrigel-based capillary-like tube formation assay. ChIP assay was used to detect H3K4me3 in SNHG12 promoter region. The binding of E2F1 to CEP55 promoter region was analyzed with ChIP and dual luciferase reporter assays. RIP assay was used to detect the binding of SNHG12 to E2F1. Finally, the effect of SNHG12 on the tumor formation and angiogenesis of RCC was assessed in nude mouse xenograft model.ResultsSNHG12 was highly expressed in RCC tissues and cells, and it was related to the poor prognosis of RCC patients. SNHG12 knockdown significantly inhibited RCC cell proliferation, migration, and invasion and HUVEC angiogenesis. KMT2B up-regulated SNHG12 expression through modifying H3K4me3 in its promoter region. In addition, SNHG12 promoted CEP55 expression by recruiting the transcription factor E2F1. Knockdown of SNHG12 blocked E2F1 recruitment and down-regulated the expression of CEP55, thereby inhibiting tumor formation and angiogenesis in nude mice.ConclusionThe evidence provided by our study highlighted the involvement of KMT2B in up-regulation of lncRNA as well as the transcription of CEP55, resulting in the promotion of angiogenesis and growth of RCC.

GPNMB overexpression is associated with extensive bone metastasis and poor prognosis in renal cell carcinoma

Glycoprotein non-metastatic protein B (GPNMB) promotes bone metastasis (BM) in various types of cancer. However, GPNMB expression and its function in patients with renal cell carcinoma (RCC) and BM is still unknown. Therefore, the clinical significance of GPNMB and its biological function in RCC with BM was investigated in the present study. A total of 31 patients with RCC and BM were retrospectively collected. The association between GPNMB protein expression level on the primary tumor and the clinicopathological characteristics of the patients was analyzed. Kaplan-Meier analysis was used to investigate the association between GPNMB expression and the prognosis of the patients. The effects of GPNMB inhibition on cell proliferation, migration and invasion in RCC cells were investigated using short hairpin (sh)RNA. High GPNMB expression level was significantly associated with the number (P=0.001) and the extent of BM (P=0.001), Fuhrman grade (P=0.037), and ERK expression level (P=0.003) of the primary tumor. In addition, GPNMB overexpression was significantly associated with poor prognosis with respect to overall survival time (P=0.001). Furthermore, a specific shRNA sequence targeting the GPNMB gene was constructed and transduced into the ACHN cell line, using a lentivirus vector to obtain a stable cell line with low mRNA expression level of GPNMB. Low GPNMB expression level inhibited RCC cell proliferation, which was measured using a Cell Counting Kit-8 assay. Cell migration and invasion ability was significantly decreased in GPNMB knockdown RCC cells compared with that in cells transduced with the negative control shRNA. In addition, the protein expression levels of phosphorylated ERK were lower in the GPNMB shRNA-transduced ACHN cells compared with those in the control cells. Therefore, these results suggested that GPNMB plays an important role in tumor progression in RCC with BM. Furthermore, it might serve as a predictive marker for BM and as a poor prognostic factor in RCC with BM. GPNMB downregulation suppressed the proliferation, migration and invasion of the RCC cells, which may be mediated through the inhibition of the ERK signaling pathway.

MiR-101-3p Serves as a Tumor Suppressor for Renal Cell Carcinoma and Inhibits Its Invasion and Metastasis by Targeting EZH2.

Background The role of miRNAs in renal cell carcinoma (RCC) is not certain. We wanted to study the biological functions and potential mechanisms of miR-101-3p in RCC. Methods miR-101-3p was inhibited in A498 and OSRC-2 (two RCC cell lines). We studied its effect on cell invasion and proliferation. Target EZH2 of miR-101-3p was designated by different methods, including luciferase functional analysis and Western blotting. The expression level of the target gene in treated cells was quantitatively analyzed by quantitative real-time polymerase chain reaction. In addition, induction of miR-101-3p to prevent tumor formation of A498 cells in mice was further studied. Results The overexpression of miR-101-3p significantly inhibited the proliferation, migration, and invasion in two RCC cells. Western blotting and luciferase functional analysis indicated that miR-101-3p regulated the expression of EZH2 in two cell lines. Mice inoculated with A498 and OSRC-2 cells transfected with miR-101-3p mimics showed significantly smaller xenografts and weaker EZH2 expression levels than the control group. Conclusions miR-101-3p inhibited RCC cell proliferation, migration, and invasion by targeting EZH2.

Epigenetic silencing of ZBTB28 promotes renal cell carcinogenesis.

Zinc finger and BTB domain-containing protein 28 (ZBTB28) is a potential tumor suppressor for some cancers. However, its epigenetic regulation and functions in renal cell carcinoma (RCC) remain to be elucidated. The expression of ZBTB28 mRNA was analyzed by semi-quantitative reverse transcription polymerase chain reaction (PCR) in nine RCC cell lines and normal kidney tissues. Methylation status of ZBTB28 promoter was assessed by methylation-specific PCR in RCC cell lines, primary RCC, tumors and adjacent tissues. The involvement of ZBTB28 in cell proliferation and migration was investigated. ZBTB28 promoter was hypermethylated in 88.9% (8/9) of RCC cell lines with reduced ZBTB28 mRNA expression, and could be reversed by DNA methyltransferase inhibitors. The methylation of ZBTB28 promoter was detected in 73.5% (36/49) of primary RCC tissues, compared with 7.1% (1/14) in normal tissues. Overexpression of ZBTB28 significantly inhibited RCC cell proliferation and migration, and induced apoptosis. Further analyses revealed that ZBTB28 upregulation could inhibit multiple oncogenic signaling transduction pathways. ZBTB28 is frequently silenced by promoter methylation in RCC pathogenesis and functions as a novel tumor suppressive gene. ZBTB28 may be a potential target for the development of RCC therapeutic strategies.

MiR-224-5p Contained in Urinary Extracellular Vesicles Regulates PD-L1 Expression by Inhibiting Cyclin D1 in Renal Cell Carcinoma Cells.

Simple SummaryThe detailed effects of abundant microRNAs contained in extracellular vesicles (EVs) on renal cell carcinoma (RCC) progression are still unclear. This study identified the overexpression of miR-224-5p in urinary EVs of RCC patients. miR-224-5p suppressed RCC cell proliferation and induced cell cycle arrest through inhibiting cyclin D1 expression. PD-L1 protein abundance was increased by miR-224-5p, and this regulation could be transmitted via EVs intercellularly. These findings may shed light on biomarker discovery for RCC immunotherapy.The abundant miRNAs in urinary extracellular vesicles (EVs) represent ideal reservoirs for biomarker discovery, especially in renal cell carcinoma (RCC). However, the content and biological functions of microRNAs contained in urinary EVs in RCC remain ambiguous. In this study, urinary EVs were isolated and characterized from RCC patients and healthy volunteers. Differentially expressed microRNAs in urinary EVs were screened by small RNA sequencing. The target gene and biological functions of selected microRNAs were investigated through multifaceted methods. Results indicated that miR-224-5p was significantly upregulated in urinary EVs of RCC patients compared to healthy volunteers. The overexpression of miR-224-5p inhibited RCC cell proliferation and induced cell cycle arrest. The gene CCND1 encoding cyclin D1 was identified as a direct target of miR-224-5p via prediction and validation. Moreover, the invasive and metastatic abilities of RCC cells were enhanced by miR-224-5p. Interestingly, miR-224-5p also increased the stability of PD-L1 protein by inhibiting CCND1. This effect could be transmitted via EVs and further promoted the resistance of RCC cells to T cell-dependent toxicity. In summary, urinary EVs containing miR-224-5p were identified as a potential biomarker in RCC. Regulation of PD-L1 protein expression by miR-224-5p through suppressing CCND1 elucidates new roles of miR-224-5p in RCC progression.

Parthenolide inhibits the tumor characteristics of renal cell carcinoma.

Parthenolide has been demonstrated to have anticancer effects against various types of cancer. However, the functional role of parthenolid has yet to be clearly reported in renal cell carcinoma (RCC). The aim of the present study was to investigate the effect of parthenolide in RCC 786‑O and ACHN cells. CCK‑8 and colony‑formation assays were used to observe the proliferation of RCC 786‑O and ACHN cells. Migration and invasion abilities were assessed through Transwell assays. The stem cell‑like properties of RCC cell lines were evaluated by mammosphere formation assay. Western blot analysis was used to investigate the metastasis and epithelial‑mesenchymal transition (EMT) induced by parthenolide on the expression levels of MMP2, MMP9, E‑cadherin, N‑cadherin, vimentin and snail. The results revealed that when the cells were treated with various concentrations of parthenolide, the rate of proliferation and growth was decreased in 786‑O and ACHN cells. The number of invasive cells in a field was approximately 170, 90, 40 and 190, 150, 70 in 786‑O and ACHN cells with 0, 4 and 8µM of parthenolide treatment. MMP‑2/‑9 expression (P<0.05) was inhibited by parthenolide. The protein levels of E‑cadherin were increased (P<0.05) and N‑cadherin, vimentin and snail were decreased (P<0.05) by parthenolide treatment. In addition, Parthenolide inhibited the expression of cancer stem cell markers and the PI3K/AKT pathway. The present study confirmed that parthenolide inhibited RCC cell proliferation and metastasis and suppressed the stem cell‑like properties of RCC cell lines, which could be a potential strategy to treat RCC. However, further molecular mechanisms of parthenolide in RCC should be observed and reported in the future.

BRD4 inhibition sensitizes renal cell carcinoma cells to the PI3K/mTOR dual inhibitor VS-5584.

Activation of the PI3K/AKT/mTOR pathway promotes the progression of renal cell carcinoma (RCC). This study tested the anti-RCC cell activity of the PI3K/mTOR dual inhibitor, VS-5584. We show that VS-5584 inhibited PI3K/AKT/mTORC1/2 activation in established (786-O and A498 lines) and primary RCC cells, thereby suppressing cell survival, proliferation, migration and cell cycle progression. VS-5584 induced significant apoptosis in RCC cells. A daily single oral dose of VS-5584 (20 mg/kg) significantly inhibited 786-O tumor growth in vivo. VS-5584 treatment of 786-O tumor xenografts and RCC cells resulted in feedback upregulation of bromodomain-containing protein 4 (BRD4). Furthermore, BRD4 inhibition (by JQ1 and CPI203), knockdown or complete knockout potentiated VS-5584-induced RCC cell death and apoptosis. Conversely, forced overexpression of BRD4 attenuated the cytotoxicity of VS-5584 in 786-O cells. Collectively, VS-5584 potently inhibits RCC cell proliferation and survival. Its anti-tumor activity is further enhanced by the targeted inhibition of BRD4.

RETRACTED ARTICLE: CircTLK1 promotes the proliferation and metastasis of renal cell carcinoma by sponging miR-136-5p

BackgroundCircular RNAs (circRNAs), a novel type of noncoding RNA (ncRNA), are covalently linked circular configurations that form via a loop structure. Accumulating evidence indicates that circRNAs are potential biomarkers and key regulators of tumor development and progression. However, the precise roles of circRNAs in renal cell carcinoma (RCC) remain unknown.MethodsThrough circRNA high-throughput sequencing of RCC cell lines, we identified the circRNA TLK1 (circTLK1) as a novel candidate circRNA derived from the TLK1 gene. qRT-PCR detected the mRNA, circRNA and miRNA expression levels in RCC tissues and cells. Loss-of function experiments were executed to detect the biological roles of circTLK1 in the RCC cell phenotypes in vitro and in vivo. RNA-FISH, RNA pull-down, dual-luciferase reporter, western blot and immunohistochemistry assays were used to investigate the molecular mechanisms underlying the functions of circTLK1.ResultscircTLK1 is overexpressed in RCC, and expression is positively correlated with distant metastasis and unfavorable prognosis. Silencing circTLK1 significantly inhibited RCC cell proliferation, migration and invasion in vitro and in vivo. circTLK1 was mainly distributed in the cytoplasm and positively regulated CBX4 expression by sponging miR-136-5p. Forced CBX4 expression reversed the circTLK1 suppression-induced phenotypic inhibition of RCC cells. Moreover, CBX4 expression was positively correlated with VEGFA expression in RCC tissues. CBX4 knockdown significantly inhibited VEGFA expression in RCC cells.ConclusionCollectively, our findings demonstrate that circTLK1 plays a critical role in RCC progression by sponging miR-136-5p to increase CBX4 expression. circTLK1 may act as a diagnostic biomarker and therapeutic target for RCC.

VHL-HIF-2α axis-induced SMYD3 upregulation drives renal cell carcinoma progression via direct trans-activation of EGFR.

It has been well established that the von Hippel-Lindau/hypoxia-inducible factor α (VHL-HIFα) axis and epidermal growth factor receptor (EGFR) signaling pathway play a critical role in the pathogenesis and progression of renal cell carcinoma (RCC). However, few studies have addressed the relationship between the two oncogenic drivers in RCC. SET and MYND domain-containing protein 3 (SMYD3) is a histone methyltransferase involved in gene transcription and oncogenesis, but its expression and function in RCC remain unclear. In the present study, we found that SMYD3 expression was significantly elevated in RCC tumors and correlated with advanced tumor stage, histological and nuclear grade, and shorter survival. Depletion of SMYD3 inhibited RCC cell proliferation, colony numbers, and xenograft tumor formation, while promoted apoptosis. Mechanistically, SMYD3 cooperates with SP1 to transcriptionally promote EGFR expression, amplifying its downstream signaling activity. TCGA data analyses revealed a significantly increased SMYD3 expression in primary RCC tumors carrying the loss-of-function VHL mutations. We further showed that HIF-2α can directly bind to the SMYD3 promoter and subsequently induced SMYD3 transcription and expression. Taken together, we identify the VHL/HIF-2α/SMYD3 signaling cascade-mediated EGFR hyperactivity through which SMYD3 promotes RCC progression. Our study suggests that SMYD3 is a potential therapeutic target and prognostic factor in RCC.

Cell proliferation is induced in renal cell carcinoma through miR-92a-3p upregulation by targeting FBXW7.

Renal cell carcinoma (RCC) is the most common type of kidney cancer whose incidence has gradually increased worldwide. MicroRNAs (miRNAs) represent a type of short endogenous non-coding RNA containing approximately 22 nucleotides, which are capable of regulating mRNAs at the post-transcriptional level in human cells. miRNAs have been demonstrated to mediate gene expression by influencing important regulatory genes. Accumulating evidence indicates that certain miRNAs are involved in RCC development. The present study investigated the underlying mechanism and functional role of miR-92a-3p in RCC cells using reverse transcription-quantitative polymerase chain reaction, western blotting, 3′ UTR luciferase assay, cell proliferation assay and soft agar assay. The results demonstrated that miR-92a-3p expression level is significantly upregulated in RCC tissues and cell lines; however, F-box and WD repeat domain containing 7 (FBXW7) expression level was significantly downregulated in RCC tissues and cell lines. Subsequently, whether FBXW7 could be considered as a direct target of miR-92a-3p in RCC cells was investigated. The results demonstrated that miR-92a-3p overexpression significantly promoted RCC cell proliferation and colony formation. Conversely, miR-92a-3p downregulation significantly inhibited RCC cell proliferation and colony formation. In addition, FBXW7 knockdown significantly enhanced RCC cell proliferation and colony formation. Conversely, FBXW7 overexpression significantly inhibited RCC cell proliferation and colony formation. Collectively, these results demonstrated that miR-92a-3p/FBXW7 pathway may represent a novel strategy and therapeutic target for RCC.