Androgen receptor (AR) signaling inhibitors provide limited survival benefits to patients with prostate cancer (PCa), and worse, few feasible genomic lesions restrict targeted treatment to PCa. Thus, a better understanding of the critical dependencies of PCa may enable more feasible therapeutic approaches to the dilemma. We performed a kinome-scale CRISPR/Cas9 screen and identified cyclin-dependent kinase 12 (CDK12) as being conservatively required for PCa cell survival. Suppression of CDK12 by the covalent inhibitor THZ531 led to an obvious anti-PCa effect. Mechanistically, THZ531 downregulated AR signaling and preferentially repressed a distinct class of CDK12 inhibition-sensitive transcripts (CDK12-ISTs), including prostate lineage-specific genes, and contributed to cellular survival processes. Integration of the super-enhancer (SE) landscape and CDK12-ISTs indicated a group of potential PCa oncogenes, further conferring the sensitivity of PCa cells to CDK12 inhibition. Importantly, THZ531 strikingly synergized with multiple AR antagonists. The synergistic effect may be driven by attenuated H3K27ac signaling on AR targets and an intensive SE-associated apoptosis pathway. In conclusion, we highlight the validity of CDK12 as a druggable target in PCa. The synergy of THZ531 and AR antagonists suggests a potential combination therapy for PCa.

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BackgroundDoublecortin-like kinase 1 (DCLK1) has been proven to be involved in numerous tumors, while its role in prostate cancer (PCa) is still unclear. This study aimed at investigating the expression pattern and prognostic value of DCLK1 in PCa.Patients and methodsReal-time polymerase chain reaction and Western blot were employed to determine DCLK1 mRNA and protein levels in 25 paired fresh samples of PCa and benign prostatic hyperplasia (BPH) as well as in PCa cell lines. Immunohistochemistry (IHC) was also performed in 125 PCa and 65 BPH tissues to assess DCLK1 expression. Then, the association of DCLK1 expression with clinicopathological parameters and biochemical recurrence (BCR) after radical prostatectomy was statistically analyzed. In addition, the role of DCLK1 in PCa cell proliferation, migration, and invasion was evaluated by using MTT and transwell assays.ResultsThe mRNA and protein levels of DCLK1 were markedly higher in the fresh samples of PCa than that in BPH. Consistently, IHC revealed increased expression of DCLK1 in PCa paraffin-embedded tissues compared with BPH. Moreover, increased DCLK1 expression was significantly associated with postoperative Gleason grading (P=0.012), pathological T stage (P=0.001), seminal vesicle invasion (P=0.026), and lymph node involvement (P=0.017), respectively. The Kaplan–Meier curve analysis demonstrated that high DCLK1 expression was associated with lower postoperative BCR-free survival (bRFS). Furthermore, multivariate Cox analysis showed that postoperative Gleason grading (P=0.018), pathological T stage (P<0.001), seminal vesicle invasion (P=0.012), lymph node involvement (P=0.014), and DCLK1 expression (P=0.014) were independent predictors of BCR. In vitro, the overexpression and knockdown of DCLK1 in PCa cell lines indicated that DCLK1 could promote cell proliferation, migration, and invasion.ConclusionIncreased DCLK1 expression is associated with PCa aggressiveness and may independently predict poor bRFS in patients with PCa.

Renal cell carcinoma (RCC) displays an increasing incidence and mortality rate worldwide in recent years. More and more evidence demonstrated microRNAs function as positive or negative regulatory factors in many cancers, while the role of miR-301a in RCC is still unclear. Material and Methods: The expression and clinical significance of miR-301a were assessed via bioinformatic software on open microarray datasets of the Cancer Genome Atlas (TCGA) and then confirmed by quantitative real-time PCR (qRT-PCR) in RCC cell lines. Loss of function assays were performed in RCC cell lines both in vitro and in vivo. Cell Counting Kit-8 (CCK-8), flow cytometry, luciferase reporter assays, Western blotting, and immunohistochemistry were employed to explore the mechanisms of the effect of miR-301a on RCC. Results: By analyzing RCC clinical specimens and cell lines, we found a uniform increased miR-301a in expression in comparison with normal renal tissue or normal human proximal tubule epithelial cell line (HK-2). In addition, miR-301a upregulation correlated advanced stage and poor prognosis of clear cell RCC (ccRCC). Anti-miR-301a could inhibit growth and cell cycle G1/S transition in RCC cell lines. Moreover, we found that PTEN was identified as a direct target of miR-301a that might partially interrupt miR-301a-induced G1/S transition. Importantly, nude-mouse models revealed that knockdown of miR-301a delayed tumor growth. Conclusion: These results indicate that miR-301a functions as a tumor-promoting miRNA through regulating PTEN expression, representing a novel therapeutic target for RCC.

Metabolic dysfunction is seen in cancer cells where increased glycolysis provides energy for growth. Circular RNAs (circRNAs) are thought to assist in glucose metabolism and the switch to glycolysis. Through screening, we found that circVAMP3 was necessary for both glycolytic and proliferative activities in renal cell carcinoma (RCC). Furthermore, circVAMP3 expression was elevated in RCC patients in correspondence with TNM stage. Mechanistically, circVAMP3 was observed to interact directly with lactate dehydrogenase A (LDHA) and modulate its activity. The circVAMP3–LDHA interaction facilitated LDHA phosphorylation at tyrosine 10 (Y10) catalyzed by the upstream kinase fibroblast growth factor receptor type 1 (FGFR1). Therefore, this study reveals a novel molecular mechanism by which circVAMP3 promotes glycolysis and proliferation through regulating the enzymatic activity of glycolytic enzyme, suggesting that circVAMP3 may represent an RCC biomarker and treatment target.