RESUMEN
Citron kinase (CIT) is a Rho-effector protein kinase that is associated with several types of cancer. However, the role of CIT in prostate cancer (PCa) is unclear. The current study utilized microarray data obtained from The Cancer Genome Atlas, which was analyzed via Biometric Research Program array tools. Additionally, reverse transcription-quantitative (RT-q)PCR was performed to compare the mRNA expression of CIT in PCa tissue and in benign prostatic hyperplasia. The protein expression of CIT was detected in a consecutive cohort via immunochemistry and CIT was screened as a potential oncogene in PCa. The results of RT-qPCR demonstrated that the mRNA expression of CIT was increased in PCa tissues. Furthermore, immunochemistry revealed that CIT protein expression was positively associated with age at diagnosis, Gleason grade, serum PSA, clinical T stage, risk group, lymph node invasion and metastasis. When compared with the low expression group, patients with a high CIT expression exhibited shorter survival rates, cancer specific mortalities (CSM) and biochemical recurrence (BCR). In addition, multivariate analysis revealed that CIT was a potential predictor of CSM and BCR. The results revealed that CIT is overexpressed during the malignant progression of PCa and may be a predictor of a poor patient prognosis.
RESUMEN
Ras and a-factor-converting enzyme 1 (Rce1) is located in the endoplasmic reticulum (ER) and is thought to be responsible for endoproteolytic processing of the vast majority of CAAX proteins. Endoplasmic reticulum stress (ERS) plays an important role in renal cell carcinoma (RCC); however, the expression and role of Rce1 in RCC have not been extensively studied. We aimed to investigate the expression of Rce1 in RCC tissues and its molecular mechanism in ERS-induced apoptosis in RCC 786-O cells. We first used western blotting, quantitative reverse transcriptase-polymerase chain reaction, and immunohistochemistry to detect the Rce1 expression in renal carcinoma tissues and paracancerous tissues. It was found that Rce1 expression was upregulated in RCC tissues, and its positive expression level was strongly associated with clinicopathologic features. Next, we detected the expression of Rce1 in human embryonic kidney cell line HEK293 and human renal carcinoma cell lines 786-O, ACHN, and A498. Higher expression of Rce1 was found in human renal carcinoma cell lines, especially in 786-O cells. Knockdown of Rce1 in 786-O cells increased apoptosis and inhibited proliferation (P < 0.05). Moreover, downregulation of Rce1 upregulated the expression of the pro-apoptotic protein Bax, but downregulated the expression of the anti-apoptotic protein Bcl-2. Further studies showed that downregulation of Rce1 also affected the expression of ERS factors. In conclusion, our results indicated that Rce1 plays a key role in RCC. Low expression of Rce1 might indirectly increase apoptosis and inhibit proliferation of renal carcinoma cells through ERS.
