Miconazole induces protective autophagy in bladder cancer cells

Autophagy plays a dual function in cancer progression; autophagy activation can support cancer cell survival or contribute to cell death. Miconazole, a Food and Drug Administration-approved antifungal drug, has been implicated in oncology research recently. Miconazole was found to exert antitumor effects in various tumors, including bladder cancer (BC). However, whether it provokes protective autophagy has been never discussed. We provide evidence that miconazole induces protective autophagy in BC for the first time. The results indicated that 1A/1B-light chain 3 (LC3)-II processing and p62 expression were elevated after miconazole exposure. Also, adenosine monophosphate-activated protein kinase phosphorylation was increased after miconazole treatment. We also confirmed the autophagy-promoting effect of miconazole in the presence of bafilomycin A1 (Baf A1). The result indicates that a combination treatment of miconazole and Baf A1 improved LC3-II processing, confirming that miconazole promoted autophagic flux. The acridine orange, Lysotracker, and cathepsin D staining results indicate that miconazole increased lysosome formation, revealing its autophagy-promoting function. Finally, miconazole and autophagy inhibitor 3-methyladenine cotreatment further reduced the cell viability and induced apoptosis in BC cells, proving that miconazole provokes protective autophagy in BC cells. Our findings approve that miconazole has an antitumor effect in promoting cell apoptosis; however, its function of protective autophagy is needed to be concerned in cancer treatment.