Renal Cell Carcinoma Tumorigenesis Research Articles

Quantitative Global Proteome and Lysine Succinylome Analyses Reveal the Effects of Energy Metabolism in Renal Cell Carcinoma.

In light of the increasing incidence of renal cell carcinoma (RCC), its molecular mechanisms have been comprehensively explored in numerous recent studies. However, few studies focus on the influence of multi-factor interactions during the occurrence and development of RCC. This study aims to investigate the quantitative global proteome and the changes in lysine succinylation in related proteins, seeking to facilitate a better understanding of the molecular mechanisms underlying RCC. LC-MS/MS combined with bioinformatics analysis are used to quantitatively detect the perspectives at the global protein level. IP and WB analysis were conducted to further verify the alternations of related proteins and lysine succinylation. A total of 3,217 proteins and 1,238 lysine succinylation sites are quantified in RCC tissues, and 668 differentially expressed proteins and 161 differentially expressed lysine succinylation sites are identified. Besides, expressions of PGK1 and PKM2 at protein and lysine, succinylation levels are significantly altered in RCC tissues. Bioinformatics analysis indicates that the glycolysis pathway is a potential mechanism of RCC progression and lysine succinylation may plays a potential role in energy metabolism. These results can provide a new direction for exploring the molecular mechanism of RCC tumorigenesis.

Decreased miR-200a-3p is a key regulator of renal carcinoma growth and migration by directly targeting CBL.

Although emerging evidence has revealed that microRNAs (miRNAs) dysregulation contribute to carcinogenesis, the mechanism underlying their roles in renal cell carcinoma (RCC) is unclear. The purpose of the current study was to analyze the association of miR-200a-3p expression with RCC and to understand potential novel target genes, functions and mechanisms of miR-200a-3p in RCC. MiR-200a-3p expression levels were first measured by quantitative real-time polymerase chain reaction and in situ hybridization in pairs of RCC tissue samples. Next, the potential miR-200a-3p target gene was analyzed using a combination of computer-aided algorithms, luciferase reporter assays and Western blotanalysis. Finally, the biological roles of miR-200a-3p in RCC tumorigenesis were investigated both in vitro by 5-ethynyl-20-deoxyuridine, apoptosis assay and transwell assay, as well as in vivo using a xenograft mouse model. Our results demonstrated that miR-200a-3p was remarkably downregulated in RCC tissues compared with normal adjacent tissue, and CBL is a direct target of miR-200a-3p. An inverse correlation between miR-200a-3p and CBL was observed in RCC tissue samples. Mechanistic investigations revealed that ectopic expression of miR-200a-3p in RCC cell lines suppressed cell proliferation and migration and enforced cell apoptosis by directly inhibiting CBL in vitro and in vivo, whereas silencing miR-200a-3p resulted in the opposite effects. Additionally, overexpressing CBL abolished the effects induced by miR-200a-3p overexpression. Taken together, our results show that the miR-200a-3p/CBL regulation axis is a novel mechanism underlying RCC pathogenesis and may serve as a candidate biomarker and therapeutic target in RCC.

Abstract 4625: Tumor expression of PIM kinases in renal cell carcinoma and the association with disease progression

Abstract Hypoxia-inducible factor (HIF) plays an important role in the tumorigenesis of renal cell carcinoma (RCC). Mutational inactivation of the von Hippel-Lindau (VHL) tumor suppressor gene, which is the most frequent molecular event, has been implicated in HIF overexpression. Recent studies found that PIM kinases increase HIF expression in cancer. The PIM Kinases are a family of highly conserved serine/threonine kinases consisting of three isoforms (PIM1, PIM2, and PIM3). PIM kinases play multiple roles in promoting cell proliferation and survival and preventing apoptosis. The expression and the potential function of PIM kinases in RCC remain unclear. Thus, we examined the expression patterns and the clinical significance of the three individual PIM kinases in RCC. PIM expression was examined by immunohistochemical staining tumor tissue and adjacent non-tumor tissue samples from 218 patients with clear cell RCC (ccRCC), including 60 patients with metastatic ccRCC. The expression of each PIM kinase in primary and metastatic ccRCC tissues comparing with adjacent normal tissues was analyzed with variables including tumor stage, grade and survival. Effect of PIM kinase on cell growth in ACHN and 786-O RCC cell lines was examined by individual PIM knockdown with specific siRNA followed by in vitro proliferation assay. Effect of PIM kinase on RCC cell motility was examined by siRNA followed by in vitro Matrigel-based invasion assay. Expression of PIM1, PIM2 and PIM3 was detected in the majority of ccRCC samples (185, 85%), but localization of isoforms differed. PIM1 expression was higher in the nucleus than in cytoplasm, while the reverse was true for PIM 2 and 3. PIM2 and PIM3 expression was higher in cytoplasm than in the nucleus. Higher expression of PIM1 and PIM2 in tumor tissues was significantly associated with metastasis. Nuclear PIM2 was associated with poorly differentiated ccRCC cells. ccRCC patients with increased nuclear PIM2 expression had significantly poorer survival compared with patients with low nuclear PIM2. siRNA-PIM2, but not siRNA-PIM1 and siRNA-PIM3, significantly reduced proliferation of ACHN and 786-O cells. Further, knockdown of PIM2 by siRNA reduced the ability of cell invasion in 786-O cells. In conclusion, PIM kinases, especially PIM2, are associated with ccRCC progression, indicating that PIM kinases may serve as potential markers for metastatic ccRCC. Targeting PIM kinases may have a therapeutic potential in ccRCC. This work was supported by NIH/NCI grant CA067267, CA085142 (Johnson, CS) and National Cancer Institute (NCI) grant P30 CA016056 involving the use of Roswell Park Cancer Institute's Bioinformatics, Pathology Resource Network, Genomics, and Clinical Data Network Shared Resources. Citation Format: Wei Luo, Yingyu Ma, Eduardo Cortes, Angela Omilian, Wiam Bshara, Gissou Azabdaftari, Brittany Bunch, Candace Johnson, Donald Trump. Tumor expression of PIM kinases in renal cell carcinoma and the association with disease progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4625.

PO-136 SOX2 is a novel biomarker for high-risk ewing sarcoma

IntroductionKidney cancer represents 2%–3% of all cancer cases and is an insidious cancer with poor prognosis in metastatic stages associated with chemo- and radio-resistance. Targeted therapies such as antiangiogenic or immunomodulatory agents are developed but present low response rates. Identification of new therapeutic targets for future drug development is a challenge to improve kidney cancer treatment. HOX transcription factors are interesting targets in many solid tumours and leukaemia. Particularly, HOXA9 has been associated with metastatic potential of ovarian and prostate cancers or with aggressiveness in glioblastoma or pancreas cancer. HOXA9 is normally regulated by EZH2, a frequently dysregulated/mutated actor in cancer and in renal cell carcinoma (RCC) particularly. Of interest, HOXC11, another HOX transcription factor, was previously shown to play a role in RCC. Our study aimed to investigate the role of HOXA9 in RCC and to identify if it may be an interesting therapeutic target in this cancer.Material and methodsThe potential role of HOXA9 in RCC was first evaluated by TCGA analysis. Then, HOXA9 was invalidated using lentivirally-expressed shRNAs, to subsequently evaluate biological impacts (survival, migration/invasion) and to perform global gene expression analysis in HOXA9-expressing RCC cell lines. In vivo, HOXA9-invalidated cells were orthotopically xenografted into immunodeficient mice and followed by bioluminescence imaging.Results and discussionsTCGA analysis showed that survival rate of RCC patients who exhibit high HOXA9 expression is significantly lower compared to patients with low expression (p=0.0014). In RCC cell lines, HOXA9 invalidation led to cell death and impacted cell migration and invasion. Transcriptomic analysis identified HOXA9 regulated pathways and genes known to play a role in RCC aggressiveness. In vivo, invalidation of HOXA9 abolished tumorigenesis. Macroscopic and microscopic analyses demonstrated the absence of tumour with HOXA9-invalidated cells.ConclusionWe identified HOXA9 as a novel actor of RCC tumorigenesis and aggressiveness, and propose that it could be a potential therapeutic target. These results could pave the way for new targeted therapies in kidney cancer.

Evaluation and prognostic significance of manganese superoxide dismutase in clear cell renal cell carcinoma

The antioxidant enzyme manganese superoxide dismutase (MnSOD) is up-regulated in renal cell carcinoma (RCC) and has been implicated in multiple stages of RCC tumorigenesis and progression. However, the prognostic significance of MnSOD in RCC has not been fully elucidated. This study aimed to investigate the expression profile of MnSOD in clear cell RCC (ccRCC) tissues and evaluate the clinical significance of this enzyme in ccRCC patients. MnSOD mRNA was assessed in 42 ccRCC and 33 normal kidney tissues using the Oncomine database, and its protein was detected in 145 ccRCCs and 3 normal tissues by immunohistochemistry staining. The Oncomine database confirmed higher MnSOD mRNA expression in ccRCC than in normal tissues, and immunohistochemistry analysis revealed that MnSOD protein expression was inversely associated with pathologic grade, clinical stage, tumor size, M status, and cancer-specific survival. In addition, univariate survival analysis demonstrated that high-grade, late-stage, large tumors, stage M1, and low MnSOD expression were associated with a poorer prognosis for cancer-specific survival, and further multivariate analysis revealed that tumor grade, stage, M1 stage, and MnSOD were identified as independent prognostic factors for cancer-specific survival in patients with ccRCC. Collectively, these findings imply that MnSOD is a promising prognostic marker in ccRCC and implies that oxidative stress might be involved in the tumorigenesis and progression of ccRCC.

Knockdown of NF-κB1 by shRNA Inhibits the Growth of Renal Cell Carcinoma In Vitro and In Vivo.

Renal cell carcinoma (RCC) accounts for approximately 2%–3% of human malignancies and is the most aggressive among urologic tumors. Biological heterogeneity, drug resistance, and chemotherapy side effects are the biggest obstacles to the effective treatment of RCC. The NF-κB transcription factor is one of several molecules identified to be responsible for the aggressive phenotype of this tumor. In the past decade, several studies have demonstrated the activation of NF-κB in RCC, and many have implicated NF-κB1 (p50) as an important molecule in tumor progression and metastasis. In the present study, a lentivirus was used to deliver shRNA targeting NF-κB1 into mouse RCC (Renca) cells. It was determined that the knockdown of the NF-κB1 gene led to a reduction in cell proliferation and late apoptosis/necrosis in vitro. Flow cytometry analysis demonstrated G2/M arrest in the cells. In addition, immunoblotting analysis revealed a significant increase in cyclin B1 and Bax. In vivo experiments showed that Renca-shRNA-NF-κB1 cells have significantly diminished tumorigenicity. Moreover, immunohistochemical analysis revealed an increase in necrotic areas of Renca-shRNA-NF-κB1 tumors. Thus, this study indicates that downregulation of NF-κB1 can suppress RCC tumorigenesis by inducing late apoptosis/necrosis. Therefore, NF-κB1 may be a potential therapeutic target for RCC.

Long Noncoding RNA Small Nucleolar RNA Host Gene 1 (SNHG1) Promotes Renal Cell Carcinoma Progression and Metastasis by Negatively Regulating miR-137.

BackgroundData on the expression of RCC tissues from the GEO database and patient survival data from TCGA were used to explore the prognostic significance of long noncoding RNA SNHG1. SNHG1 has been reported to participate in the development of several cancers, but, the underlying mechanism of SNHG1 in renal cell carcinoma (RCC) has not been reported. The purpose of our study was to investigate the potential function of SNHG1 in RCC.Material/MethodsThe expression of SNHG1 in 40 cases of RCC and adjacent normal tissues and 5 cell lines was detected by qRT-PCR. Cell proliferation, Transwell assay, and Western blotting assay were carried out to investigate the biological function of SNHG1. A rescue experiment was performed to verify that miR-137 can partly impede the effect of SNHG1 on renal cancer cells.ResultsSNHG1 was identified to be overexpressed in RCC tissues and RCC cell lines. High levels of SNHG1 were correlated with poor prognosis of RCC patients. Knockdown of SNHG1 suppressed the proliferation, invasion, and EMT capacity in RCC. Moreover, miR-137 abrogated the effect of SNHG1 on RCC.ConclusionsSNHG1 is significantly upregulated in RCC and renal cancer cell lines. Overexpression of SNHG1 participates in RCC tumorigenesis by regulating miR-137.

Alternative splice variants of DCLK1 mark cancer stem cells, promote self‐renewal and drug‐resistance, and can be targeted to inhibit tumorigenesis in kidney cancer

Renal cell carcinoma (RCC) is a common and devastating disease characterized by a hypoxic microenvironment, epithelial-mesenchymal transition and potent resistance to therapy evidencing the presence of cancer stem cells (CSCs). Various CSC markers have been studied in RCC, but overall there is limited data on their role and most markers studied have been relatively nonspecific. Doublecortin-like kinase 1 (DCLK1) is a validated CSC marker in the gastrointestinal tract and evidence for an equivalent role in other cancers is accumulating. We used bioinformatics, immunohistochemistry, flow cytometry, spheroid self-renewal and chemoresistance assays in combination with overexpression and siRNA-knockdown to study the stem cell-supportive role of DCLK1 alternative splice variants (DCLK1 ASVs) in RCC. To target tumor cells expressing DCLK1 ASVs directly, we developed a novel monoclonal antibody (CBT-15) and delivered it systemically to RCC tumor xenografts. DCLK1 ASVs were overexpressed, enriched together with CSC markers and predictive of overall and recurrence-free survival in RCC patients. In vitro, DCLK1 ASVs were able to directly stimulate essential molecular and functional characteristics of renal CSCs including expression of aldehyde dehydrogenase, self-renewal and resistance to FDA-approved receptor tyrosine kinase and mTOR inhibitors, while targeted downregulation of DCLK1 reversed these characteristics. Finally, targeting DCLK1 ASV-positive cells with the novel CBT-15 monoclonal antibody blocked RCC tumorigenesis in vivo. These findings establish DCLK1 as a CSC marker with implications for therapy, disease progression and survival in RCC and demonstrate the therapeutic value of DCLK1-targeted monoclonal antibodies against renal CSCs.

MicroRNA-384 Inhibits the Growth and Invasion of Renal Cell Carcinoma Cells by Targeting Astrocyte Elevated Gene 1.

MicroRNAs (miRNAs) are emerging as pivotal regulators in the development and progression of various cancers, including renal cell carcinoma (RCC). MicroRNA-384 (miR-384) has been found to be an important cancer-related miRNA in several types of cancers. However, the role of miR-384 in RCC remains unclear. In this study, we aimed to investigate the potential function of miR-384 in regulating tumorigenesis in RCC. Here we found that miR-384 was significantly downregulated in RCC tissues and cell lines. Overexpression of miR-384 significantly inhibited the growth and invasion of RCC cells, whereas inhibition of miR-384 had the opposite effects. Bioinformatic analysis and luciferase reporter assay showed that miR-384 directly targeted the 3′-untranslated region of astrocyte elevated gene 1 (AEG-1). Further data showed that miR-384 could negatively regulate the expression of AEG-1 in RCC cells. Importantly, miR-384 expression was inversely correlated with AEG-1 expression in clinical RCC specimens. Moreover, miR-384 regulates the activation of Wnt signaling. Overexpression of AEG-1 significantly reversed the antitumor effects of miR-384. Overall, these findings suggest that miR-384 suppresses the growth and invasion of RCC cells via downregulation of AEG-1, providing a potential therapeutic target for the treatment of RCC.

Cyanidin Curtails Renal Cell Carcinoma Tumorigenesis

Background/Aims: Cyanidin is an anthocyanin found in many foods. Although its variable antioxidant levels are well-documented, little is known about its effects on renal cell carcinoma (RCC) tumorigenesis. This study, therefore, investigated the effects of cyanidin on the proliferation, migration, and invasion of renal cell carcinoma lines and demonstrated, for the first time, significant inhibitory effects of cyanidin on RCC tumorigenesis. Methods: RCC cells were treated with different doses of cyanidin and the effects were tested by Cell Counting Kit-8 reagent, clone formation assay, transwell assay, and flow cytometry. Moreover, the cyanidin-mediated mechanism that curtailed tumorigenesis was analyzed by RNA sequencing (RNA-seq). Sequencing data from The Cancer Genome Atlas (TCGA) were used to compare the expression of both early growth response protein 1 (EGR1) and selenoprotein W (SEPW1) in RCC and tumor-free adjacent normal tissue samples. Real-time PCR (RT-PCR) and/or western blot were used to assess the expression of E-cadherin, cleaved-caspase3, Bcl2, p62, and ATG4. Results: We found significantly greater induction of cell-cycle arrest, apoptosis, and suppression of RCC cell invasion and migration at concentrations of 25 µM and 100 µM than at a concentration of 50 µM. It was also discovered, first through RNA-seq then confirmed by RT-PCR, that cyanidin (100 µM) inhibited RCC carcinogenesis through EGR1 and SEPW1. TCGA data indicated that the expression level of EGR1 was lower and that of SEPW1 was higher in RCC tumor tissue than in normal tissues. Moreover, western blot and/or RT-PCR indicated that cleaved-caspase3 was enhanced and E-cadherin was inhibited by cyanidin treatment. Furthermore, western blot and RT-PCR also showed regulation of p62 and ATG4, which are associated with autophagy. Cyanidin in vivo significantly inhibited the growth of xenografts in nude mice. Conclusions: The results of this study showed the therapeutic potential of cyanidin for the treatment of RCC and the prevention of recurrence and metastasis.

MiR‑660‑5p is associated with cell migration, invasion, proliferation and apoptosis in renal cell carcinoma.

Renal cell carcinoma (RCC) is a common malignant tumor of the urinary system with poor prognosis. microRNAs (miRNAs) are a class of small, non‑coding RNA molecules that serve important roles in biological and pathological processes in several types of human tumors. miRNA (miR)‑660‑5p is dysregulated in many human cancers; however, its role in renal cell carcinoma is currently unclear. In the present study, reverse transcription‑quantitative polymerase chain reaction was performed to examine the expression levels of miR‑660‑5p in RCC tissues and paired normal adjacent tissues (NATs). To determine the function of miR‑660‑5p in RCC cells, wound‑healing and Matrigel assays were performed to determine the effects of miR‑660‑5p on cell migration and invasion, respectively. MTT and Cell Counting kit‑8 assays were performed to determine the effects of miR‑660‑5p on RCC cell proliferation. In addition, flow cytometric analysis was performed to validate the effects of miR‑660‑5p on apoptosis. The results indicated that miR‑660‑5p expression was downregulated in RCC tissues compared with NATs. Restoration of miR‑660‑5p expression using synthetic mimics may suppress cell migration, invasion and proliferation, and induce cell apoptosis, while using synthetic inhibitors may promote cell migration, invasion and proliferation, and suppress cell apoptosis. These results suggested that miR‑660‑5p may serve a tumor suppressive role in RCC tumorigenesis.

Transferrin receptor 1 upregulation in primary tumor and downregulation in benign kidney is associated with progression and mortality in renal cell carcinoma patients.

The central dysregulated pathway of clear cell (cc) renal cell carcinoma (RCC), the von Hippel Lindau/hypoxia inducible factor-α axis, is a key regulator of intracellular iron levels, however the role of iron uptake in human RCC tumorigenesis and progression remains unknown. We conducted a thorough, large-scale investigation of the expression and prognostic significance of the primary iron uptake protein, transferrin receptor 1 (TfR1/CD71/TFRC), in RCC patients. TfR1 immunohistochemistry was performed in over 1500 cores from 574 renal cell tumor patient tissues (primary tumors, matched benign kidneys, metastases) and non-neoplastic tissues from 36 different body sites. TfR1 levels in RCC tumors, particularly ccRCC, were significantly associated with adverse clinical prognostic features (anemia, lower body mass index, smoking), worse tumor pathology (size, stage, grade, multifocality, sarcomatoid dedifferentiation) and worse survival outcomes, including after adjustments for tumor pathology. Highest TfR1 tissue levels in the non-gravid body were detected in benign renal tubule epithelium. Opposite to TfR1 changes in the primary tumor, TfR1 levels in benign kidney dropped during tumor progression and were inversely associated with worse survival outcomes, independent of tumor pathology. Quantitative measurement of TfR1 subcellular localization in cell lines demonstrated mixed cytoplasmic and membranous expression with increased TfR1 in clusters in ccRCC versus benign renal cell lines. Results of this study support an important role for TfR1 in RCC progression and identify TfR1 as a novel RCC biomarker and therapeutic target.

The M6A methyltransferase METTL3: acting as a tumor suppressor in renal cell carcinoma.

We aimed to study the role of METTL3 in renal cell carcinoma (RCC) carcinogenesis and development. Immunohistochemistry was performed in clinical tissue microarray. Expression level of METTL3 in RCC tissues and cell lines was evaluated by quantitative real-time PCR (qRT-PCR) and western blot. Then, the effects of METTL3 on proliferation, migration, invasion and cell cycle were studied in RCC cells. Additionally, in vivo study was carried out in nude mice. Negative METTL3 expression was associated with larger tumor size (P=0.010) and higher histological grade (P=0.021). Moreover, RCC patients with positive METTL3 expression had an obvious longer survival time (P=0.039). METTL3 mRNA and protein expression was lower in RCC samples compared with adjacent non-tumor samples, and lower in RCC cell lines (CAKI-1, CAKI-2 and ACHN) compared with HK-2. Afterwards, knockdown of METTL3 could obviously promote cell proliferation, migration and invasion function, and induce G0/G1 arrest. In contrast, up-regulation of METTL3 could inhibit such functions and reduce G0/G1 arrest. Additionally, up-regulation of METTL3 significantly suppressed tumor growth in vivo. Furthermore, significant changes in epithelial-to-mesenchymal transition (EMT) and PI3K-Akt-mTOR pathways were observed. Overall, our findings demonstrated that METTL3 might have a carcinostasis role in cell proliferation, migration, invasion function and cell cycle of RCC, indicating METTL3 may act as a novel marker for tumorigenesis, development and survival of RCC.

The IGF-I/JAK2-STAT3/miR-21 signaling pathway may be associated with human renal cell carcinoma cell growth.

Renal cell carcinoma (RCC) is the highest mortality rate of the genitourinary cancers, and the treatment options are very limited. Thus, identification of molecular mechanisms underlying RCC tumorigenesis, is critical for identifying biomarkers for RCC diagnosis and prognosis. To validate whether the IGF-I/JAK2-STAT3/miR-21 signaling pathway is associated with human RCC cell growth. qRT-PCR and Western blotting were used to detect the mRNA and protein expression levels, respectively. The MTT assay was performed to determine cell survival rate. The Annexin V-FITC/PI apoptosis detection kit was used to detect cell apoptosis. We employed RCC tissues and cell lines (A498; ACHN; Caki-1; Caki-2 and 786-O) in the study. IGF-I, and its inhibitor (NT-157) were administrated to detect the effects of IGF-I on the expression of miR-21 and p-JAK2. JAK2 inhibitor (AG490), and si-STAT3 were used to detect the effects of JAK2/STAT3 signaling pathway on the expression of miR-21. In our study, we firstly showed that the expression levels of IGF-I and miR-21 were up-regulated in RCC tissues and cell lines. After exogenous IGF-I treatment, the expression levels of miR-21, p-IGF-IR and p-JAK2 were significantly increased, whereas NT-157 treatment showed the reversed results. Further study indicated that JAK2 inhibitor or si-STAT3 significantly reversed the IGF-I-induced miR-21 expression level. Finally, we found that IGF-I treatment significantly prompted human RCC cell survival and inhibited cell apoptosis, and NT-157 treatment showed the reversed results. The IGF-I/JAK2-STAT3/miR-21 signaling pathway may be associated with human RCC cell growth.

Low expression of long noncoding RNA CASC2 indicates a poor prognosis and promotes tumorigenesis in thyroid carcinoma

Recently, long noncoding RNAs (lncRNAs) have been shown to be linked to regulate different biological processes, such as cell growth, differentiation and tumorigenesis. LncRNAs have been identified to be promising clinical biomarkers in various tumors. Long noncoding RNAs cancer susceptibility candidate 2 (CASC2) has recently been demonstrated to be correlated to tumorigenesis in renal cell carcinoma, lung carcinoma, glioma, and gastric carcinoma. Nevertheless, the research on the biological function and clinical significance of CASC2 in thyroid carcinoma are still unclear. In this research, we focused on the relationship between CASC2 expression and clinicopathological factors in thyroid cancer. We found that the low expression of CASC2 correlated with multifocality and advanced tumor-node-metastasis (TNM) stage. Kaplan-Meier survival analysis and multivariate analysis showed that CASC2 expression may be an independent prognostic factor in human thyroid carcinoma. Moreover, the area under the receiver operating characteristic (ROC) curve of CASC2 indicated that its diagnostic value in thyroid carcinoma. Additionally, overexpression of CASC2 significantly inhibited the proliferation of thyroid carcinoma cells and arrested cell cycle at G0/G1 stage in thyroid cancer cells. Our findings showed that CASC2 may be a potential prognostic marker and therapeutic target.

Induction of cell cycle arrest by increasing GTP-RhoA levels via Taxol-induced microtubule polymerization in renal cell carcinoma

Renal cell carcinoma (RCC) is the most common neoplasm of the kidney in adults, accounting for ~3% of adult malignancies. Understanding the underlying mechanism of RCC tumorigenesis is necessary to improve patient survival. The present study revealed that Taxol-induced microtubule (MT) polymerization causes cell cycle arrest and an increase in guanosine triphosphate-Ras homology gene family, member A (GTP-RhoA) protein expression. Disruption of Taxol-induced MT polymerization reversed GTP-RhoA expression and cell cycle arrest. The localization and redistribution of MTs and RhoA were consistent in cells with MT bundles and those without. Decreased GTP-RhoA had no marked effect on Taxol-induced MT bundling, however, it reduced the proportion of cells in G2/M phase. Taken together, Taxol-induced MT polymerization regulated the protein expression levels of GTP-RhoA and cell cycle arrest. However, the alteration in GTP-RhoA expression did not influence MT arrangement, suggesting that GTP-RhoA serves a pivotal role in Taxol-induced MT polymerization and cell cycle arrest in RCC.

MicroRNA‑373 promotes tumorigenesis of renal cell carcinoma in vitro and in vivo.

Renal cell carcinoma (RCC) is the most common type of malignancy in the kidney parenchyma. MicroRNAs (miRNAs) are small non‑coding RNAs that serve a role in various biological processes associated with human cancer. The present study aimed to explore the potential role of miRNA (miR)‑373 in the tumorigenesis of RCC. The effects of miR‑373 on the proliferation and apoptosis of RCC cells were determined using MTT, colony formation and flow cytometry assays invitro. The results demonstrated that miR‑373 was significantly upregulated in RCC tissues and cell lines. Knockdown of miR‑373 expression reduced cell proliferation and promoted cell apoptosis in 786‑O and ACHN cell lines. Furthermore, an invivo tumorigenicity assay revealed that knockdown of miR‑373 expression reduced tumor growth in nude mice. Taken together, these data indicate that miR‑373 may promote tumorigenesis in RCC, suggesting that miR‑373 may act as a potential therapeutic target against RCC.

Periostin promotes migration and invasion of renal cell carcinoma through the integrin/focal adhesion kinase/c-Jun N-terminal kinase pathway.

Periostin (POSTN) is an extracellular matrix protein which is overexpressed in a variety of cancers and has been related to tumorigenesis of renal cell carcinoma. However, the involvement of POSTN in renal cell carcinoma migration, invasion, and their underlying mechanisms has not been established. In this study, renal cell carcinoma cell lines stably overexpressing POSTN were established using a lentiviral vector, and the effects of POSTN on renal cell carcinoma cell migration and invasion were investigated. POSTN overexpression increased the migration and invasion capabilities of renal cell carcinoma cell lines as well as activity of matrix metalloproteinase-2 and matrix metalloproteinase-9. Integrin αvβ3 and αvβ5 antibodies inhibited POSTN overexpression or recombinant POSTN-induced focal adhesion kinase activation, cell migration, and invasion. Furthermore, lentivirus-mediated focal adhesion kinase knockdown and c-Jun N-terminal kinase inhibitor reduced POSTN-enhanced phosphorylation of c-Jun N-terminal kinase, matrix metalloproteinase-9 and matrix metalloproteinase-2 expressions, cell migration, and invasion. Our research thus indicates that POSTN promotes renal cell carcinoma cell migration and invasion through interaction with integrins αvβ3 and αvβ5 and subsequent activation of the focal adhesion kinase/c-Jun N-terminal kinase pathway. These results suggest that POSTN plays a critical role in renal cell carcinoma metastasis and may represent a potential target for novel therapeutic approaches against renal cell carcinoma.

Downregulation of microRNA-15a suppresses the proliferation and invasion of renal cell carcinoma via direct targeting of eIF4E.

The downregulation of microRNA-15a has been reported in several human tumors. However, its expression and functional importance in renal cell carcinoma (RCC) remain unknown. The aim of the present study was to investigate its expression, biological functions and underlying mechanisms in RCC tumorigenesis. The expression levels of miR-15a were examined by qRT-PCR in 40 RCC specimens and adjacent-paired normal tissues. Cell Counting Kit-8 (CCK-8), colony formation, flow cytometry and Transwell assays were used to explore the potential influence of miR-15a transfection on RCC cell proliferation, the cell cycle, cell apoptosis, and cell invasion. Luciferase reporter assays were performed to confirm the potential target of miR-15a, in combination with qRT-PCR, western blotting and immunohistochemical assays. We found that miR-15a was significantly downregulated in most RCC specimens compared with adjacent normal tissues (P<0.01). Overexpression of miR-15a inhibited cellular growth, suppressed invasion and arrested cells at the G1/G0 phase, and induced cell apoptosis in RCC cells. Luciferase assays revealed that miR-15a directly targeted the binding site of the 3′-untranslated region (3′-UTR) of eIF4E, and inhibited its expression at both mRNA and protein levels. eIF4E expression was negatively associated with miR-15a expression in RCC tissues. eIF4E overexpression treatment partially abrogated the inhibitory effect of miR-15a on cell proliferation and invasion, as well as inactivated P13K/AKT/mTOR signaling in RCC cells. In conclusion, the present study indicated that miR-15a downregulation was associated with cell proliferation and invasion by directly targeting eIF4E during RCC progression. Thus, it may serve as a potential tumor suppressor and therapeutic target for the treatment of RCC.

Identification of miR‑195‑3p as an oncogene in RCC.

There is increasing evidence that the deregulation of microRNAs (miRNAs; miRs) contributes to tumorigenesis. Previous studies have shown that miR‑195 is downregulated in various types of cancer. The present study aimed to investigate the function and expression levels of miR‑125b. Results of qPCR revealed that miR‑195‑3p, the mature sequence of miR‑195, was upregulated in renal cell carcinoma (RCC) tissues and cell lines (786‑O, 769P and ACHN). This indicated that the function and role of miR‑195‑3p may differ in different types of tumor. To assess the function of miR‑195‑3p in RCC cell lines, cell proliferation was examined using MTT and CCK‑8 assays, mobility was assessed using a cell scratch assay, Transwell migration assay and invasion assay, and apoptosis was examined using flow cytometry. These assessments were also performed in cells with upregulated or downregulated miR‑195‑3p via transfection with synthesized miR‑195‑3p mimic or inhibitor. The results revealed that the overexpression of miR‑195‑3p promoted 786‑O and ACHN RCC cell proliferation, migration and invasion, and inhibited cell apoptosis, whereas the downregulation of miR‑195‑3p suppressed cell proliferation, migration and invasion, and induced cell apoptosis. These results indicated that miR‑195‑3p was associated with the tumorigenesis of RCC, with further investigations to focus on the pathway and use of miR‑195‑3p as a clinical biomarker for RCC.