Suppresses Autophagy in Prostate Cancer Cells via Inhibiting m6A-Modification of mRNA.

Background: Activating autophagy promotes the invasion and progression of prostate cancer (PCa). Tetraspanin 1 () has been found to promote autophagy flux and its up-regulation can enhance the migration of PCa cells. In addition, there is a binding relationship between and the N6-methyladenosine (m6A) demethylase AlkB homolog 5 (). Therefore, we wanted to know whether could affect autophagy by regulating expression, and thereby participate in PCa malignant progression.

Methods: The expression of and in PCa was examined by quantitative real-time polymerase chain reaction (qRT-PCR), and the functional tests included cell counting kit-8 and 5-ethynyl-2'-deoxyuridine (EdU) staining assays. The expression of autophagy-related proteins was confirmed by western blot. Detection of the m6A level of was performed using methylated RNA immunoprecipitation sequencing (MeRIP)-qPCR.

Results: was significantly downregulated in PCa cells (LNCaP, DU145 and PC3 cells; < 0.001). Overexpression of inhibited cell viability and the number of EdU-positive cells ( < 0.01, < 0.001), decreased the ratio of microtubule-associated protein light chain 3B (LC3B)-II/LC3B-I, and promoted P62 protein expression in LNCaP and DU145 cells ( < 0.001). The m6A level of was high in LNCaP and DU145 cells, but was inhibited by the overexpression of ( < 0.001). overexpression promoted cell viability ( < 0.001), increased EdU-positive cells and the LC3B-II/LC3B-I ratio ( < 0.001, < 0.05), reduced P62 protein expression ( < 0.05, < 0.001), and reversed the regulation of overexpression in LNCaP and DU145 cells ( < 0.01, < 0.001).

Conclusions: Promoting expression may inhibit PCa autophagy by reducing the m6A level of .