As a catalytic subunit of the positive transcription elongation factor b (P-TEFb), cyclin-dependent kinase 9 (CDK9) has been demonstrated to contribute to carcinogenesis. This review focuses on the development of selective CDK9 inhibitors and proteolysis-targeting chimera (PROTAC) degraders. Twenty selective CDK9 inhibitors and degraders are introduced along with their structures, IC50 values, in vitro and in vivo experiments, mechanisms underlying their inhibitory effects, and combination regimens. NVP-2, MC180295, fadraciclib, KB-0742, LZT-106, and 21e have been developed mainly for treating solid tumors, and most of them work only on certain genotypes of solid tumors. Only VIP152 has been proven to benefit the patients with advanced high-grade lymphoma (HGL) and solid tumors in clinical trials. Continued efforts to explore the molecular mechanisms underlying the inhibitory effects, and to identify suitable tumor genotypes and combination treatment strategies, are crucial to demonstrate the efficacy of selective CDK9 inhibitors and degraders in tumor therapy.

IntroductionCystoscopy is the standard methodology for diagnosis of bladder cancer (BC), but it is invasive and relatively expensive. Previous studies have found that urinary exosomal long non-coding RNAs (lncRNAs) may act as potential noninvasive biomarkers for diagnosis. Here we identified urinary exosomal lncRNAs that are differentially expressed between BC and controls, and established a panel for diagnosis of BC.MethodsWe performed RNA sequencing in urinary exosomes of 7 controls and 7 patients, subsequently the differentially expressed lncRNAs were detected in training cohort (50 controls and 50 patients) and validation cohort (43 controls and 43 patients). The diagnostic power of lncRNAs for BC was calculated by the area under curve (AUC). The panel for diagnosis of BC was calculated by logistic regression.ResultsThe results of RNA sequencing in urinary exosomes showed that 240 upregulated lncRNAs and 275 downregulated lncRNAs were differentially expressed. The levels of MKLN1-AS, TALAM1, TTN-AS1 and UCA1 in BC patients were higher than that in controls in the training and validation cohort by real-time PCR. Using logistic regression, with the combination of these four lncRNAs and NMP22, we identified a panel of five parameters capable of classifying BC patients versus controls on the basis of the training cohort (AUC=0.850). Moreover, the performance of the panel exhibited better performance than either single parameter in the validation cohort.ConclusionCollectively, this study confirmed the diagnostic value of lncRNAs for BC by high-throughout urinary exosomal RNA sequencing.