Myelosuppression, a side effect of anticancer drugs, makes people more susceptible to infectious diseases by compromising the immune system. When a cancer patient develops a contagious disease, treatment with an anticancer drug is suspended or postponed to treat the infectious disease. If there was a drug that suppresses the growth of cancer cells among antibacterial agents, it would be possible to treat both infectious diseases and cancer. Therefore, this study investigated the effect of antibacterial agents on cancer cell development. Vancomycin (VAN) had little effect on cell proliferation against the breast cancer cell, MCF-7, prostate cancer cell, PC-3, and gallbladder cancer cell, NOZ C-1. Alternatively, Teicoplanin (TEIC) and Daptomycin (DAP) promoted the growth of some cancer cells. In contrast, Linezolid (LZD) suppressed the proliferation of MCF-7, PC-3, and NOZ C-1 cells. Therefore, we found a drug that affects the growth of cancer cells among antibacterial agents. Next, when we examined the effects of the combined use of existing anticancer and antibacterial agents, we found VAN did not affect the growth suppression by anticancer agents. However, TEIC and DAP attenuated the growth suppression of anticancer agents. In contrast, LZD additively enhanced the growth suppression by Docetaxel in PC-3 cells. Furthermore, we showed that LZD inhibits cancer cell growth by mechanisms that involve phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway suppression. Therefore, LZD might simultaneously treat cancer and infectious diseases.
Keywords: Linezolid; antibacterial agent; cancer; drug repositioning; phosphatidylinositol 3-kinase (PI3K); protein kinase B (Akt).