Abstract
Overuse and abuse of antibiotics can increase the risk of cancer. Chloramphenicol can inhibit both bacterial and mitochondrial protein synthesis, causing mitochondrial stress and decreased ATP biosynthesis. Chloramphenicol can accelerate cancer progression; however, the underlying mechanisms of chloramphenicol in carcinogenesis and cancer progression are still unclear. We found that chloramphenicol can induce matrix metalloproteinase (MMP)-13 expression and increase MMP-13 protein in conditioned medium, resulting in an increase in cancer cell invasion. Chloramphenicol also activated c-Jun N-terminal kinases (JNK) and phosphatidylinositol 3-kinase (PI-3K)/Akt signaling, leading to c-Jun protein phosphorylation. The activated c-Jun protein has been proven to activate binding to the MMP-13 promoter and also upregulate the amount of MMP-13. Both the SP 600125 (JNK inhibitor) and LY 294002 (PI-3K/Akt inhibitor) can inhibit chloramphenicol-induced c-Jun phosphorylation, MMP-13 expression, and cell invasion. Overexpression of the dominant-negative JNK and PI-3K p85 subunit also negate chloramphenicol-induced responses. Other antibiotics that cause mitochondrial stress and a decrease in ATP biosynthesis also induce MMP-13 expression. These findings suggest that chloramphenicol-induced PI-3K/Akt, JNK phosphorylation, and activator protein 1 activation might function as a novel mitochondrial stress signal that result in an increase of MMP-13 expression and MMP-13-associated cancer cell invasion. The findings of this study confirms that chloramphenicol, and other 70S ribosomal inhibitors, should be administered with caution, especially during cancer therapy.