Mechanism In Renal Cell Carcinoma Research Articles

SRSF3 suppresses RCC tumorigenesis and progression via regulating SP4 alternative splicing

Abnormal alternative splicing (AS) caused by dysregulated expression of splicing factors plays a crucial role in tumorigenesis and progression. The serine/arginine-rich (SR) RNA-binding protein family is a major class of splicing factors regulating AS. However, their roles and mechanisms in renal cell carcinoma (RCC) development and progression are not fully understood. Here, we found that SR splicing factor 3 (SRSF3) was an important splicing factor affecting RCC progression. SRSF3 was downregulated in RCC tissues and its low level was associated with decreased overall survival time of RCC patients. SRSF3 overexpression suppressed RCC cell malignancy. Mechanistically, the binding of SRSF3 to SP4 exon 3 led to the inclusion of SP4 exon 3 and the increase of long SP4 isoform (L-SP4) level in RCC cells. L-SP4, but not S-SP4 overexpression suppressed RCC cell malignancy. Meanwhile, L-SP4 participated in SRSF3-mediated anti-proliferation by transcriptionally promoting SMAD4 expression. Taken together, our findings provide new insights into the anticancer mechanism of SRSF3, suggesting that SRSF3 may serve as a novel potential therapeutic target for RCC.

Label-free quantitative proteomics reveals the mechanisms of Aurora kinase B in renal cell carcinoma.

Renal cell carcinoma is the most common form of kidney cancer which is a global threat to human health, needing to explore effective therapeutic targets and treatment methods. Aurora kinase B acts as an important carcinogenic role in various kinds of tumors, while its mechanism in renal cell carcinoma is indistinct. Herein we explore the underlying mechanism of Aurora kinase B in renal cell carcinoma. Label-free quantitative proteomics analysis was employed to analyze the differentially expressed proteins in 786-O cells which were treated with si-Aurora kinase B or si-ctrl. In the current study, 169 differentially expressed proteins were identified. The top 10 upregulated proteins were MX2, IFI44L, ISG20, DDX58, F3, IFI44, ECE1, PRIC285, NIT1, and IFIT2. The top 10 downregulated proteins were FKBP9, FSTL1, DDAH1, TGFB2, HMGN3, COIL, FAM65A, PTPN14, ARFGAP2, and EIF2C2. GO enrichment analysis showed that these differentially expressed proteins participated in biological processes, including defense response to virus, response to virus, and type I interferon signaling pathway. These differentially expressed proteins participated in cellular components, including focal adhesion, cell-substrate adherens junction, cell-substrate junction, and endoplasmic reticulum lumen. These differentially expressed proteins participated in molecule functions, including guanyl nucleotide binding, nucleotidase activity, double-stranded RNA binding, 2'-5'-oligoadenylate synthetase activity, and virus receptor activity. Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that the significantly changed proteins including OAS3, OAS2, JAK1, TAP1, and RAC1 were involved in Epstein-Barr virus infection. Taken together, our results demonstrate the possible mechanisms that Aurora kinase B may participate in renal cell carcinoma. These findings may provide insights into tumorigenesis and a theoretical basis for developing potential therapies of renal cell carcinoma.

Abnormal expression of CEBPB promotes the progression of renal cell carcinoma through regulating the generation of IL-6

BackgroundThe CCAAT/enhancer-binding protein beta (CEBPB), a transcription factor regulating immune and inflammatory responses, has been implicated in the pathogenesis of various malignancies. However, its specific regulatory mechanism in renal cell carcinoma (RCC) remains poorly understood. MethodsThe expression of CEBPB was detected in RCC cells and tissues using qRT-PCR, western blotting and immunohistochemistry. ELISA assay was used to detect the immune factors regulated by CEBPB in supernatants. Additionally, western blotting was employed to measure the phosphorylation level of STAT3 and the expression levels of its downstream target genes. ResultsCEBPB was found to be overexpressed in both RCC tissues and cell lines, and its higher expression was associated with a lower survival rate. In RCC cells, CEBPB enhances the expression of IL6, consequently promoting the phosphorylation of STAT3 and the expression of its downstream target genes. This mechanism ultimately facilitates tumor progression. ConclusionsThe dysregulated expression of CEBPB facilitates RCC progression through the IL6/STAT3 pathway. CEBPB is a potential diagnostic markers and a novel effective therapeutic target for RCC patients.

Circular RNA CSPP1 motivates renal cell carcinoma carcinogenesis and the Warburg effect by targeting RAC1 through microRNA-493-5p.

Circular RNAs (circRNAs) take on regulatory roles in renal cell carcinoma (RCC). The research's goal was to figure out circ-CSPP1's role and molecular mechanism in RCC. The results clarified that circ-CSPP1 expression was enhanced in RCC. Down-regulating circ-CSPP1 refrained the proliferation, migration, invasion, and Warburg effect (aerobic glycolysis), but accelerated apoptosis of RCC cells. The luciferase activity assay exhibited that circ-CSPP1 could perform as an endogenous sponge for miR-493-5p. Elevating miR-493-5p repressed RCC progression. The bioinformatics website starBase confirmed that ras-related C3 botulinum toxin substrate 1 (RAC1) was a target gene of miR-493-5p. Circ-CSPP1 up-regulated RAC1 by sponging miR-493-5p, and elevating RAC1 could turn around the effect of down-regulating circ-CSPP1 on RCC cells. Taken together, circ-CSPP1 is identified as a novel RCC-promoting RNA that could serve as a latent therapeutic target for RCC therapy.

Hsa_circ_0003596, as a novel oncogene, regulates the malignant behavior of renal cell carcinoma by modulating glycolysis

BackgroundThis research was planned to analyze hsa_circ_0003596 (circCOL5A1) and glycolysis-focused mechanisms in renal cell carcinoma (RCC).MethodscircCOL5A1, miR-370-5p, and PRKCSH levels were determined in RCC tissues and selected cell lines by RT-qPCR and/or Western blot. RCC cells after corresponding transfection were tested by colony formation assay, EdU assay, Transwell assay, and flow cytometry to analyze cell proliferation, invasion, migration, and apoptosis. Meanwhile, glycolysis in cells was evaluated by measuring glucose consumption, lactic acid, and ATP production, as well as immunoblotting for HK2 and PKM2. In addition, circCOL5A1 knockdown was performed in animal experiments to observe tumor growth and glycolysis. Finally, the ceRNA network between circCOL5A1, miR-370-5p, and PRKCSH was studied by luciferase reporter assay and RIP experiment.ResultscircCOL5A1 and PRKCSH were highly expressed and miR-370-5p was poorly expressed in RCC. circCOL5A1 knockdown depressed RCC proliferation, invasion, migration, and glycolysis, and enhanced apoptosis. circCOL5A1 competitively adsorbed miR-370-5p. Artificial upregulation of miR-370-5p saved the pro-tumor effect of circCOL5A1 on RCC cells, as evidenced by suppression of tumor malignancy and glycolysis. miR-370-5p targeted PRKCSH. PRKCSH overexpression contributed to a reversal of the anti-tumor effect of circCOL5A1 silencing. Silencing circCOL5A1 inhibited RCC tumor growth and glycolysis.ConclusionscircCOL5A1 regulates the malignant behavior of RCC by modulating glycolysis.

GPD1L inhibits renal cell carcinoma progression by regulating PINK1/Parkin-mediated mitophagy.

Few approaches have been conducted in the treatment of renal cell carcinoma (RCC) after nephrectomy, resulting in a high mortality rate in urological tumours. Mitophagy is a mechanism of mitochondrial quality control that enables selective degradation of damaged and unnecessary mitochondria. Previous studies have found that glycerol-3-phosphate dehydrogenase 1-like (GPD1L) is associated with the progression of tumours such as lung cancer, colorectal cancer and oropharyngeal cancer, but the potential mechanism in RCC is still unclear. In this study, microarrays from tumour databases were analysed. The expression of GPD1L was confirmed by RT-qPCR and western blotting. The effect and mechanism of GPD1L were explored using cell counting kit 8, wound healing, invasion, flow cytometry and mitophagy-related experiments. The role of GPD1L was further confirmed in vivo. The results showed that GPD1L expression was downregulated and positively correlated with prognosis in RCC. Functional experiments revealed that GPD1L prevented proliferation, migration and invasion while promoting apoptosis and mitochondrial injury in vitro. The mechanistic results indicated that GPD1L interacted with PINK1, promoting PINK1/Parkin-mediated mitophagy. However, inhibition of PINK1 reversed GPD1L-mediated mitochondrial injury and mitophagy. Moreover, GPD1L prevented tumour growth and promoted mitophagy by activating the PINK1/Parkin pathway in vivo. Our study shows that GPD1L has a positive correlation with the prognosis of RCC. The potential mechanism involves interacting with PINK1 and regulating the PINK1/Parkin pathway. In conclusion, these results reveal that GPD1L can act as a biomarker and target for RCC diagnosis and therapy.

Berberine inhibits the progression of renal cell carcinoma cells by regulating reactive oxygen species generation and inducing DNA damage.

Berberine is a natural isoquinoline alkaloid that has been shown to have antitumor properties in a growing number of studies. However, its role in renal cell carcinoma remains unclear. This study investigates berberine's effect and mechanism in renal cell carcinoma. The methyl-tetrazolium, colony formation, and lactate dehydrogenase assay were used to detect proliferation and cytotoxicity, respectively. Flow cytometry, caspase-Glo 3/7 assay, and adenosine triphosphate assay were used to detect apoptosis and the adenosine triphosphate levels. Wound healing and transwell assay were used to examine the migration ability of renal cell carcinoma cells. Besides, the level of reactive oxygen species (ROS) was explored using a DCFH-DA-based kit. Additionally, western blot and Immunofluorescence assay was taken to determine the levels of relative proteins. In vitro, our findings indicated that the proliferation and migration of renal cell carcinoma cells treated with berberine in various concentrations were inhibited, while the level of ROS and apoptosis rate were increased. Furthermore, The results of western blot showed that the expression of Bax, Bad, Bak, Cyto c, Clv-Caspase 3, Clv-Caspase 9, E-cadherin, TIMP-1and γH2AX were up-regulated, while Bcl-2, N-cadherin, Vimentin, Snail, Rad51 and PCNA were down-regulated after treating with berberine with various concentration. The result of this study revealed that berberine inhibits renal cell carcinoma progression via regulating ROS generation and inducing DNA break.

Phospholipase C delta 1 inhibits WNT/β‐catenin and EGFR-FAK-ERK signaling and is disrupted by promoter CpG methylation in renal cell carcinoma

BackgroundPLCD1, located at 3p22, encodes an enzyme that mediates cellular metabolism and homeostasis, intracellular signal transduction and movement. PLCD1 plays a pivotal role in tumor suppression of several types of cancers; however, its expression and underlying molecular mechanisms in renal cell carcinoma (RCC) pathogenesis remain elusive.MethodsRT-PCR and Western blot were used to detect PLCD1 expression in RCC cell lines and normal tissues. Bisulfite treatment, MSP and BGS were utilized to explore the CpG methylation status of PLCD1 promoter. Online databases were analyzed for the association between PLCD1 expression/methylation and patient survival. In vitro experiments including CCK8, colony formation, wound-healing, transwell migration and invasion, immunofluorescence and flow cytometry assays were performed to evaluate tumor cell behavior. Luciferase assay and Western blot were used to examine effect of PLCD1 on WNT/β‐catenin and EGFR‐FAK-ERK signaling.ResultsWe found that PLCD1 was widely expressed in multiple adult normal tissues including kidney, but frequently downregulated or silenced in RCC due to its promoter CpG methylation. Restoration of PLCD1 expression inhibited the viability, migration and induced G2/M cell cycle arrest and apoptosis in RCC cells. PLCD1 restoration led to the inhibition of signaling activation of WNT/β-catenin and EGFR-FAK-ERK pathways, and the EMT program of RCC cells.ConclusionsOur results demonstrate that PLCD1 is a potent tumor suppressor frequently inactivated by promoter methylation in RCC and exerts its tumor suppressive functions via suppressing WNT/β‐catenin and EGFR‐FAK-ERK signaling. These findings establish PLCD1 as a promising prognostic biomarker and treatment target for RCC.

Integrated analysis of transcriptomics, proteomics and metabolomics data reveals the role of SLC39A1 in renal cell carcinoma.

Purpose: Accumulating evidence suggests that solute carrier family 39 member 1 (SLC39A1) conceivably function as a tumor suppressor, but the underlying mechanism in renal cell carcinoma (RCC) is poorly understood. Methods: OSRC-2 renal cancer cells were first transfected with SLC39A1 overexpressed vectors and empty vectors and then used in transcriptomics, proteomics, and metabolomics integrated analyses. Results: SLC39A1 significantly altered several metabolisms at transcriptional, protein and metabolic levels, including purine and pyrimidine metabolism, amino acids and derivatives metabolism, lactose metabolism, and free fatty acid metabolism. Additionally, SLC39A1 could promote ferroptosis, and triggered significant crosstalk in PI3K-AKT signal pathway, cAMP signal pathway, and peroxisome proliferators-activated receptor (PPAR) signal pathway. Conclusion: We found SLC39A1 transfection impaired tumor metabolism and perturbed tumor metabolism-related pathways, which was a likely cause of the alteration in cell proliferation, migration, and cell cycle progression in RCC cells. These multi-omics analyses results provided both a macroscopic picture of molecular perturbation by SLC39A1 and novel insights into RCC tumorigenesis and development.

Panels of mRNAs and miRNAs for decoding molecular mechanisms of Renal Cell Carcinoma (RCC) subtypes utilizing Artificial Intelligence approaches

Renal Cell Carcinoma (RCC) encompasses three histological subtypes, including clear cell RCC (KIRC), papillary RCC (KIRP), and chromophobe RCC (KICH) each of which has different clinical courses, genetic/epigenetic drivers, and therapeutic responses. This study aimed to identify the significant mRNAs and microRNA panels involved in the pathogenesis of RCC subtypes. The mRNA and microRNA transcripts profile were obtained from The Cancer Genome Atlas (TCGA), which were included 611 ccRCC patients, 321 pRCC patients, and 89 chRCC patients for mRNA data and 616 patients in the ccRCC subtype, 326 patients in the pRCC subtype, and 91 patients in the chRCC for miRNA data, respectively. To identify mRNAs and miRNAs, feature selection based on filter and graph algorithms was applied. Then, a deep model was used to classify the subtypes of the RCC. Finally, an association rule mining algorithm was used to disclose features with significant roles to trigger molecular mechanisms to cause RCC subtypes. Panels of 77 mRNAs and 73 miRNAs could discriminate the KIRC, KIRP, and KICH subtypes from each other with 92% (F1-score ≥ 0.9, AUC ≥ 0.89) and 95% accuracy (F1-score ≥ 0.93, AUC ≥ 0.95), respectively. The Association Rule Mining analysis could identify miR-28 (repeat count = 2642) and CSN7A (repeat count = 5794) along with the miR-125a (repeat count = 2591) and NMD3 (repeat count = 2306) with the highest repeat counts, in the KIRC and KIRP rules, respectively. This study found new panels of mRNAs and miRNAs to distinguish among RCC subtypes, which were able to provide new insights into the underlying responsible mechanisms for the initiation and progression of KIRC and KIRP. The proposed mRNA and miRNA panels have a high potential to be as biomarkers of RCC subtypes and should be examined in future clinical studies.

FBP1 /miR-24-1/enhancer axis activation blocks renal cell carcinoma progression via Warburg effect.

Warburg effect is a pivotal hallmark of cancers and appears prevalently in renal cell carcinoma (RCC). FBP1 plays a negative role in Warburg effect as a rate-limiting enzyme in gluconeogenesis, yet its mechanism in RCC remains to be further characterized. Herein, we revealed that FBP1 was downregulated in RCC tissue samples and was related to the poor survival rate of RCC. Strikingly, miR-24-1 whose DNA locus is overlapped with enhancer region chr9:95084940-95087024 was closely linked with the depletion of FBP1 in RCC. Of note, miRNAs like miR-24-1 whose DNA loci are enriched with H3K27ac and H3K4me1 modifications are belonging to nuclear activating miRNAs (NamiRNAs), which surprisingly upregulate target genes in RCC through enhancer beyond the conventional role of repressing target gene expression. Moreover, miR-24-1 reactivated the expression of FBP1 to suppress Warburg effect in RCC cells, and subsequently inhibited proliferation and metastasis of RCC cells. In mechanism, the activating role of miR-24-1 was dependent on enhancer integrity by dual luciferase reporter assay and CRISPR/Cas9 system. Ultimately, animal assay in vivo validated the suppressive function of FBP1 on 786-O and ACHN cells. Collectively, the current study highlighted that activation of FBP1 by enhancer-overlapped miR-24-1 is capable of contributing to Warburg effect repression through which RCC progression is robustly blocked, providing an alternative mechanism for RCC development and as well implying a potential clue for RCC treatment strategy.

N6-methyladenosine-modified TRAF1 promotes sunitinib resistance by regulating apoptosis and angiogenesis in a METTL14-dependent manner in renal cell carcinoma

BackgroundSunitinib resistance can be classified into primary and secondary resistance. While accumulating research has indicated several underlying factors contributing to sunitinib resistance, the precise mechanisms in renal cell carcinoma are still unclear.MethodsRNA sequencing and m6A sequencing were used to screen for functional genes involved in sunitinib resistance. In vitro and in vivo experiments were carried out and patient samples and clinical information were obtained for clinical analysis.ResultsWe identified a tumor necrosis factor receptor-associated factor, TRAF1, that was significantly increased in sunitinib-resistant cells, resistant cell-derived xenograft (CDX-R) models and clinical patients with sunitinib resistance. Silencing TRAF1 increased sunitinib-induced apoptotic and antiangiogenic effects. Mechanistically, the upregulated level of TRAF1 in sunitinib-resistant cells was derived from increased TRAF1 RNA stability, which was caused by an increased level of N6-methyladenosine (m6A) in a METTL14-dependent manner. Moreover, in vivo adeno-associated virus 9 (AAV9) -mediated transduction of TRAF1 suppressed the sunitinib-induced apoptotic and antiangiogenic effects in the CDX models, whereas knockdown of TRAF1 effectively resensitized the sunitinib-resistant CDXs to sunitinib treatment.ConclusionsOverexpression of TRAF1 promotes sunitinib resistance by modulating apoptotic and angiogenic pathways in a METTL14-dependent manner. Targeting TRAF1 and its pathways may be a novel pharmaceutical intervention for sunitinib-treated patients.

A Novel Nomogram for Prediction and Evaluation of Lymphatic Metastasis in Patients With Renal Cell Carcinoma.

BackgroundLymphatic metastasis is an important mechanism of renal cell carcinoma (RCC) dissemination and is an indicator of poor prognosis. Therefore, we aimed to identify predictors of lymphatic metastases (LMs) in RCC patients and to develop a new nomogram to assess the risk of LMs.MethodsThis study included patients with RCC from 2010 to 2018 in the Surveillance, Epidemiology, and Final Results (SEER) database into the training cohort and included the RCC patients diagnosed during the same period in the Second Affiliated Hospital of Dalian Medical University into the validation cohort. Univariate and multivariate logistic regression analysis were performed to identify risk factors for LM, constructing a nomogram. The receiver operating characteristic (ROC) curves were generated to assess the nomogram’s performance, and the concordance index (C-index), area under curve value (AUC), and calibration plots were used to evaluate the discrimination and calibration of the nomogram. The nomogram’s clinical performance was evaluated by decision curve analysis (DCA), probability density function (PDF) and clinical utility curve (CUC). Furthermore, Kaplan-Meier curves were performed in the training and the validation cohort to evaluate the survival risk of the patients with lymphatic metastasis or not. Additionally, on the basis of the constructed nomogram, we obtained a convenient and intuitive network calculator.ResultsA total of 41837 patients were included for analysis, including 41,018 in the training group and 819 in the validation group. Eleven risk factors were considered as predictor variables in the nomogram. The nomogram displayed excellent discrimination power, with AUC both reached 0.916 in the training group (95% confidence interval (CI) 0.913 to 0.918) and the validation group (95% CI 0.895 to 0.934). The calibration curves presented that the nomogram-based prediction had good consistency with practical application. Moreover, Kaplan-Meier curves analysis showed that RCC patients with LMs had worse survival outcomes compared with patients without LMs.ConclusionsThe nomogram and web calculator (https://liwenle0910.shinyapps.io/DynNomapp/) may be a useful tool to quantify the risk of LMs in patients with RCC, which may provide guidance for clinicians, such as identifying high-risk patients, performing surgery, and establishing personalized treatment as soon as possible.

LncRNA FAM13A-AS1 Promotes Renal Carcinoma Tumorigenesis Through Sponging miR-141-3p to Upregulate NEK6 Expression.

Long non-coding RNAs are a diverse catalog of RNAs that have been implicated in various aspects of tumorigenesis. Emerging evidence indicates that they play crucial roles in tumor growth, disease progression, and drug resistance. However, the clinical significance of lncRNAs in tumor behavior prediction and disease prognosis as well as the underlying mechanism in renal cell carcinoma (RCC) remains elusive. By analyzing the gene expression profiles of 539 RCC patients from the TCGA cohort and 40 RCC patients from an independent cohort, we identified FAM13A-AS1, a poorly studied lncRNA, upregulated in RCC patients. Knockdown experiments revealed that FAM13A-AS1 promotes cell proliferation, migration, and invasion by interacting with miR-141-3p. FAM13A-AS1 regulates the expression of NEK6 by decoying miR-141-3p. In addition, there was a strong positive correlation between the expression of FAM13A-AS1 and NEK6 in RCC patients. In summary, our results demonstrate the oncogenic role of FAM13A-AS1 in RCC and suggest that it promotes tumorigenesis by upregulating the expression of NEK6 by competitively binding to miR-141-3p.

Telmisartan-Induced Cytotoxicity <i>via</i> G<sub>2</sub>/M Phase Arrest in Renal Cell Carcinoma Cell Lines

Renal cell carcinoma (RCC) is the most common type of kidney cancer. Given that stage IV RCC is intractable, there is a need for a novel treatment strategy. We investigated the antitumor effects of telmisartan (TEL) and their underlying mechanisms in RCC, including their impact on apoptosis, Akt/mammalian target of rapamycin (mTOR) pathways, and the cell cycle using two human RCC cell lines: 786-O and Caki-2. Cell viability was detected via fluorescence-based assays. Cells were stained with Hoechst 33342 to observe chromatin condensation, and Western blotting was performed to analyze protein expression. The cell cycle was assessed using flow cytometry. Invasion and migration assays were performed using 24-well chambers. TEL induced cell death in a dose-dependent manner and increased the percentage of cells with high chromatin condensation and Bax/Bcl-2 ratio in both cell lines. TEL-induced cell death was attenuated by neither peroxisome proliferator-activated receptor-γ nor -δ inhibitors. Although TEL elevated c-Jun N-terminal kinase levels and p38 phosphorylation rates in Caki-2 cells, as well as extracellular signal-regulated kinase phosphorylation rates in 786-O cells, their inhibitors did not suppress TEL-induced cell death. TEL decreased Akt phosphorylation in 786-O cells and mTOR phosphorylation in both cell lines, increased the population of cells in the G2/M phase, and altered G2/M-related proteins in both cell lines. TEL moderately suppressed cell invasion and migration in 786-O and Caki-2 cells, respectively, and increased cell invasion in Caki-2 cells, suggesting a potential therapeutic role of TEL in RCC.

Doxycycline sensitizes renal cell carcinoma to chemotherapy by preferentially inhibiting mitochondrial translation

ObjectivesThe anti-cancer activity of doxycycline has been reported in many cancers but not renal cell carcinoma (RCC). This study aimed to determine the efficacy of doxycycline alone and in combination with paclitaxel and analyze the underlying mechanism in RCC.MethodsProliferation, colony formation and apoptosis assays were performed in RCC cell lines after drug treatments. An RCC xenograft mouse model was generated, and tumor growth was monitored. Mechanistic studies focused on mitochondrial translation and functions.ResultsDoxycycline at clinically achievable concentrations inhibited proliferation and colony formation and induced apoptosis in RCC cell lines. In normal kidney cells, doxycycline at the same concentrations either had no effect or was less effective. The combination index value demonstrated that doxycycline and paclitaxel were synergistic in vitro. Consistently, this combination therapy was significantly more effective than the monotherapy in RCC xenograft mice without causing significant toxicity. Mechanistic studies revealed that doxycycline acts on RCC cells via preferentially inhibiting mitochondrial DNA translation, thereby disrupting multiple mitochondrial complexes and impairing mitochondrial respiration.ConclusionsDoxycycline is a useful addition to the treatment strategy for RCC. Our work also highlights the therapeutic value of mitochondrial translation inhibition in sensitizing RCC to chemotherapy.

MicroRNA-501-3p inhibits the proliferation of kidney cancer cells by targeting WTAP.

BackgroundEmerging evidence suggests that miR‐501‐3p plays an important role in the pathogenesis and progression of various carcinomas. However, its role and underlying mechanisms in renal cell carcinoma (RCC) remain to be elucidated.MethodsQuantitative RT‐PCR, western blot, and bioinformatics methods were used to evaluate the expression of miR‐501‐3p and Wilms’ tumor 1‐associating protein (WTAP) in RCC cell lines and clinical tissues. The effects of miR‐501‐3p on the proliferation of RCC cells were investigated using flow cytometric, colony formation, and CCK8 assays. The target gene of miR‐501‐3p was confirmed by western blotting, qRT‐PCR, and dual‐luciferase reporter assays. The levels of RNA methylation with N6‐methyladenosine (m6A) following miR‐501‐3p overexpression or knockdown of its target gene were quantified using a dot‐blot assay.ResultsmiR‐501‐3p expression was significantly downregulated in human RCC cell lines and tissues. In contrast, its overexpression markedly inhibited cancer cell proliferation in vitro by inducing G1 phase arrest. Moreover, WTAP was verified as a direct target gene of miR‐501‐3p. WTAP gene knockdown alone efficiently produced the same cancer‐inhibiting effects as miR‐501‐3p overexpression, with the level of m6A in RCC cells being decreased under both scenarios. The intermolecular interaction between miR‐501‐3p and WTAP was further substantiated by rescue experiments.ConclusionRCC progression is regulated via the miR‐501‐3p/WTAP/CDK2 axis and is inhibited by the overexpression of miR‐501‐3p.

Renal Cell Carcinoma-Infiltrating CD3low Vγ9Vδ1 T Cells Represent Potentially Novel Anti-Tumor Immune Players.

Due to the highly immunogenic nature of renal cell carcinoma (RCC), the tumor microenvironment (TME) is enriched with various innate and adaptive immune subsets. In particular, gamma-delta (γδ) T cells can act as potent attractive mediators of adoptive cell transfer immunotherapy because of their unique properties such as non-reliance on major histocompatibility complex expression, their ability to infiltrate human tumors and recognize tumor antigens, relative insensitivity to immune checkpoint molecules, and broad tumor cytotoxicity. Therefore, it is now critical to better characterize human γδ T-cell subsets and their mechanisms in RCCs, especially the stage of differentiation. In this study, we aimed to identify γδ T cells that might have adaptive responses against RCC progression. We characterized γδ T cells in peripheral blood and tumor-infiltrating lymphocytes (TILs) in freshly resected tumor specimens from 20 RCC patients. Furthermore, we performed a gene set enrichment analysis on RNA-sequencing data from The Cancer Genome Atlas (TCGA) derived from normal kidneys and RCC tumors to ascertain the association between γδ T-cell infiltration and anti-cancer immune activity. Notably, RCC-infiltrating CD3low Vγ9Vδ1 T cells with a terminally differentiated effector memory phenotype with up-regulated activation/exhaustion molecules were newly detected as predominant TILs, and the cytotoxic activity of these cells against RCC was confirmed in vitro. In an additional analysis of the TCGA RCC dataset, γδ T-cell enrichment scores correlated strongly with those for CTLs, Th1 cells, “exhausted” T cells, and M1 macrophages, suggesting active involvement of γδ T cells in anti-tumor rather than pro-tumor activity, and Vδ1 cells were more abundant than Vδ2 or Vδ3 cells in RCC tumor samples. Thus, we posit that Vγ9Vδ1 T cells may represent an excellent candidate for adoptive immunotherapy in RCC patients with a high risk of relapse after surgery.

Simvastatin suppresses renal cell carcinoma cells by regulating DDX5/DUSP5

Objectives Renal cell carcinoma (RCC) has the highest mortality rate of genitourinary cancers and the incidence of RCC has risen steadily. Simvastatin has been reported to exhibit anti-tumor activity in a variety of cancers; however, its roles and molecular mechanisms in RCC remain unclear. Our aim was to evaluate the inhibitory effect of simvastatin on RCC. Methods We used a variety of methods to test the changes of RCC cell lines’ viability, migration, invasion, cell cycle and apoptosis after treatment with simvastatin. Results We found that simvastatin not only inhibited RCC cell viability, migration, and invasion, but also regulated the cell cycle and induced apoptosis. We also observed abnormal expression of DDX5 and DUSP5 in RCC cell lines. Mechanistic investigation showed that simvastatin significantly suppressed DDX5 and promoted DUSP5 expression. Conclusion Together, these results provide a novel mechanism underlying simvastatin-induced inhibition of RCC via regulation of the DDX5/DUSP5 axis.

Wild-type IDH1 inhibits the tumor growth through degrading HIF-α in renal cell carcinoma.

The purpose of our study was to explore the effect and intrinsic mechanism of wild-type IDH1 and its substrate α-KG on renal cell carcinoma (RCC). IDH1 was observed lower expression in RCC cell lines. Phenotype experiment was carried out in the wild-type IDH1 and mutant IDH1R132H plasmid treated cell line. The results showed that the wild-type IDH1 could significantly inhibit the proliferation, migration and promote the apoptosis of RCC cell lines, which were consistent with the IDH1's substrate α-KG. The mutant IDH1R132H was found to lose this biological function of IDH1. Moreover, we verified the proliferation inhibition of IDH1 in vivo. In addition, we verified the correlation between IDH1 and hypoxia signal-related proteins in vitro and in vivo, specifically, IDH1 overexpression could significantly reduce the expression of HIF-1α and HIF-2α proteins and its downstream proteins (VEGF, TGF-α). Furthermore, we preliminarily verified the possibility of α-KG in the RCC's treatment by injecting α-KG into the xenograft model. α-KG significantly reduced tumor size and weight in tumor-bearing mice. This study provided a new therapeutic target and small molecule for the study of the treatment and mechanism of RCC.