The expression and role of protein kinase C (PKC) epsilon in clear cell renal cell carcinoma

Protein kinase C epsilon (PKCε), an oncogene overexpressed in several human cancers, is involved in cell proliferation, migration, invasion, and survival. However, its roles in clear cell renal cell carcinoma (RCC) are unclear. This study aimed to investigate the functions of PKCε in RCC, especially in clear cell RCC, to determine the possibility of using it as a therapeutic target. By immunohistochemistry, we found that the expression of PKCε was up-regulated in RCCs and was associated with tumor Fuhrman grade and T stage in clear cell RCCs. Clone formation, wound healing, and Borden assays showed that down-regulating PKCε by RNA interference resulted in inhibition of the growth, migration, and invasion of clear cell RCC cell line 769P and, more importantly, sensitized cells to chemotherapeutic drugs as indicated by enhanced activity of caspase-3 in PKCε siRNA-transfected cells. These results indicate that the overexpression of PKCε is associated with an aggressive phenotype of clear cell RCC and may be a potential therapeutic target for this disease

MTHFD2 Overexpression Predicts Poor Prognosis in Renal Cell Carcinoma and is Associated with Cell Proliferation and Vimentin-Modulated Migration and Invasion

Background/Aims: To investigate the role of methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) in the clinical prognosis and cell biology of renal cell carcinoma (RCC). Methods: A total of 137 RCC tissues were evaluated by immunohistochemistry. The relationship between MTHFD2 overexpression and clinical parameters and vimentin expression was assessed. Kaplan-Meier curves and the log-rank test were applied for survival analysis according to MTHFD2 and vimentin expression in RCC tissues. The expression of MTHFD2 mRNA and protein was examined by quantitative reverse transcription PCR and western blotting, respectively. To determine further the biological activity of MTHFD2 in RCC, 786-O cells were transfected with short hairpin RNA specifically targeting MTHFD2 (shMTHFD2) with or without tumor necrosis factor (TNF)-α stimulation. Cell proliferation, cell migration and invasion and drug sensitivity were subsequently assessed using Cell Counting Kit-8, wound healing, and Transwell assays. Results: Immunohistochemical analysis demonstrated that both MTHFD2 and vimentin overexpression was positively associated with clinical staging, pathological grade, and poor overall survival (all P < 0.05). MTHFD2 expression was closely correlated with vimentin overexpression in RCC (r = 0.402, P < 0.001). After knocking down MTHFD2 expression in 786-O cells, decreased cell proliferation, migration, and invasion were observed and accompanied by the reduced expression of vimentin. The effects of MTHFD2 down-regulation could be partially restrained by TNF-α treatment. Vimentin expression and cell migration and invasion, but not cell proliferation, were reversed by TNF-α stimulation. Furthermore, treatment of 786-O cells with shMTHFD2 increased their sensitivity to chemotherapy drugs. Conclusion: The current results demonstrated that MTHFD2 was overexpressed in RCC and associated with poor clinical characteristics, vimentin expression, and cellular features connected to malignant disease, thus, implicating MTHFD2 as a potential target for RCC therapy

Tyrosine Kinase ETK/BMX Is Up-Regulated in Bladder Cancer and Predicts Poor Prognosis in Patients with Cystectomy

Deregulation of the non-receptor tyrosine kinase ETK/BMX has been reported in several solid tumors. In this report, we demonstrated that ETK expression is progressively increased during bladder cancer progression. We found that down-regulation of ETK in bladder cancer cells attenuated STAT3 and AKT activity whereas exogenous overexpression of ETK had opposite effects, suggesting that deregulation of ETK may attribute to the elevated activity of STAT3 and AKT frequently detected in bladder cancer. The survival, migration and invasion of bladder cancer cells were significantly compromised when ETK expression was knocked down by a specific shRNA. In addition, we showed that ETK localizes to mitochondria in bladder cancer cells through interacting with Bcl-XL and regulating ROS production and drug sensitivity. Therefore, ETK may play an important role in regulating survival, migration and invasion by modulating multiple signaling pathways in bladder cancer cells. Immunohistochemistry analysis on tissue microarrays containing 619 human bladder tissue samples shows that ETK is significantly upregulated during bladder cancer development and progression and ETK expression level predicts the survival rate of patients with cystectomy. Taken together, our results suggest that ETK may potentially serve as a new drug target for bladder cancer treatment as well as a biomarker which could be used to identify patients with higher mortality risk, who may be benefited from therapeutics targeting ETK activity