Aim: To investigate whether microRNA-21 was involved in mediating the chemoresistance of prostate cancer cells to docetaxel. Methods: A microarray technique was used to determine the miRNA profile in docetaxel-resistant PC3 cells. Real-time PCR was used to confirm the array results. miR-21 mimics and inhibitors were synthesized and introduced to cells using Lipofectamine 2000. Cell proliferation was examined with the CCK-8 assay. Luciferase reporter containing PDCD 3′UTR was constructed and the activity was detected by a dual luciferase assay. PDCD4 protein expression was evaluated using Western blot. Results: A docetaxel-resistant prostate cancer PC3 cell line (PC3R) was established . Using microarrays, miR-21 was found to be upregulated in PC3R cells. Ectopic expression of miR-21 increased the resistance to docetaxel in PC3 wild type cells. In contrast, silencing of miR-21 in PC3R cells sensitized the cells to docetaxel. The IC 50 values for miR-21-silencing cells and control cells were 28.31 and 35.89 nmol/L, respectively. PDCD4, a direct target gene of miR-21, could mediate chemoresistance to docetaxel in PC3 cells. Conclusion: Our findings suggest that miR-21 contributed to the resistance of PC3 cells to docetaxel, and that targeting miR-21 may offer a promising therapeutic approach in sensitizing prostate cancer to docetaxel treatment.

Although pretreatment neutrophil-lymphocyte ratio (NLR), lymphocyte-monocyte ratio (LMR), and platelet-lymphocyte ratio (PLR) are reportedly associated with clinical outcomes of many cancers, their roles in patients with bladder cancer (BCa) who undergo radical cystectomy (RC) have not been widely investigated. We analyzed relationships between preoperative NLR, LMR, PLR, and overall survival (OS) in 124 BCa patients undergoing RC. OS curves were drawn using the Kaplan-Meier method and evaluated using the log-rank test. Relationships between OS and potential confounding variables were determined using Cox's proportional hazard regression model. Decreased LMR was associated with shorter OS (P = 0.012); OS in the low PLR group was significantly longer than that in the high PLR group (P = 0.029), and NLR was not significantly associated with oncological outcomes. However, after adjusting for confounding variables, patients in the high-LMR group indicated >30% decreased mortality than the low-LMR group (hazard ratio 0.674; 95% confidence interval 0.412-0.890; P = 0.003), and PLR was not an independent predictor of OS. Our results show that preoperative LMR is a better prognostic factor in BCa patients undergoing RC, compared with NLR and PLR.

The tumorigenic role and underlying mechanisms of lipid accumulation, commonly observed in many cancers, remain insufficiently understood. In this study, we identified an AMP-activated protein kinase (AMPK)-GATA-binding protein 3 (GATA3)enoyl-CoA hydratase short-chain 1 (ECHS1) pathway that induces lipid accumulation and promotes cell proliferation in clear cell renal cell carcinoma (ccRCC). Decreased expression of ECHS1, which is responsible for inactivation of fatty acid (FA) oxidation and activation of de novo FA synthesis, positively associated with ccRCC progression and predicted poor patient survival. Mechanistically, ECHS1 downregulation induced FA and branched-chain amino acid (BCAA) accumulation, which inhibited AMPK-promoted expression of GATA3, a transcriptional activator of ECHS1. BCAA accumulation induced activation of mTORC1 and de novo FA synthesis, and promoted cell proliferation. Furthermore, GATA3 expression phenocopied ECHS1 in predicting ccRCC progression and patient survival. The AMPK-GATA3-ECHS1 pathway may offer new therapeutic approaches and prognostic assessment for ccRCC in the clinic. Significance: These findings uncover molecular mechanisms underlying lipid accumulation in ccRCC, suggesting the AMPK-GATA3-ECHS1 pathway as a potential therapeutic target and prognostic biomarker.