The antibiotic chloramphenicol may be an effective new agent for inhibiting the growth of multiple myeloma

Abstract

// Faqing Tian 1, * , Chunyan Wang 3, * , Meiqin Tang 1 , Juheng Li 1 , Xiaohui Cheng 1 , Sihan Zhang 2 , Delan Ji 1 , Yingcai Huang 1 , Huiqing Li 1 1 Department of Hematology, Longgang District People’s Hospital of Shenzhen, Guangdong, China 2 Department of Rheumatology, Longgang District People’s Hospital of Shenzhen, Guangdong, China 3 Department of Rheumatology, Lanzhou University Second Hospital, Gansu, China * These authors contributed equally to this work Correspondence to: Faqing Tian, email: trumantfq@163.com Keywords: chloramphenicol, multiple myeloma, adenosine triphosphate, apoptosis Received: December 21, 2015      Accepted: June 29, 2016      Published: July 16, 2016 ABSTRACT Chloramphenicol is an old antibiotic that also inhibits mammalian mitochondrial protein synthesis. Our studies demonstrated that chloramphenicol is highly cytotoxic to myeloma cells, acting in a dose- and time-dependent manner. Chloramphenicol sharply suppressed ATP levels in myeloma cells at concentrations ≥ 25 μg/mL. Colorimetric and clonogenic assays indicate that chloramphenicol inhibits growth of myeloma cell lines at concentrations ≥ 50 μg/mL, and inhibits primary myeloma cell growth at concentrations ≥ 25 μg/mL. Flow cytometry and Western blotting showed that chloramphenicol induces myeloma cell apoptosis at concentrations ≥ 50 μg/mL. Chloramphenicol increased levels of cytochrome c, cleaved caspase-9 and cleaved caspase-3, suggesting that myeloma cell apoptosis occurs through the mitochondria-mediated apoptosis pathway. It thus appears chloramphenicol is not only an old antibiotic, it is also a potential cytotoxic agent effective against myeloma cells. This suggests chloramphenicol may be an effective “new” drug for the treatment of myeloma.