ABSTRACT
BACKGROUND: Intravesical bacillus Calmette-Guérin (BCG) application is widely used in the treatment of superficial bladder carcinoma. Despite being an effective therapy, the pathogenicity and lethal side effects of BCG limits its usage. Intensive research has been carried out to find less toxic and more potent therapeutic agents for the treatment of bladder cancer. Researchers have focused on Mycobacterium phlei as an alternative. The cell wall extract of M. phlei is sufficient for antitumoral activity. Our preliminary experiments indicate that the fractions rich in cell wall proteins cause activation of tumor necrosis factor (TNF)-α and interleukin (IL)-12. This study aims to identify powerful and less harmful mycobacteria among 88 strains in terms of how they stimulate the immune system. METHODS: Eighty-eight mycobacterial strains were grown in Middlebrook 7H9 medium. The bacterial cells were sonicated after heat treatment. The supernatants were incubated with the monocytic cell line THP-1, followed by measurement of TNF-α and IL-12 response. RESULTS AND CONCLUSION: In addition to M. phlei, the following 12 mycobacterial strains were selected as candidates for superficial bladder tumor treatment: M. agri, M. aichiense, M. aurum, M. brumae, M. chitae, M. chubuense, M. diernhoferi, M. gadium, M. murale, M. obuense, M. tokaiense and M. vaccae.
Subject(s)
Cell Wall/immunology , Mycobacterium/immunology , Cell Line , Cell Wall/chemistry , Humans , Immunotherapy/methods , Interleukin-12/metabolism , Monocytes/immunology , Mycobacterium/chemistry , Tumor Necrosis Factor-alpha/metabolism , Urinary Bladder Neoplasms/therapyABSTRACT
Our previously synthesized 37 compounds, which are 2,5,6-substituted benzoxazole, benzimidazole, benzothiazole, and oxazolo(4,5-b)pyridine derivatives, were tested for their eukaryotic DNA topoisomerase II inhibitory activity in cell free system and 28 were found to inhibit the topoisomerase II at an initial concentration of 100 microg/ml. After further testing at a lower range of concentrations, 12 derivatives, which were considered as positive topoisomerase inhibitors, exhibited IC50 values between 11.4 and 46.8 microM. Etoposide was used as the standard reference drug to compare the inhibitor activity. Among these compounds, 2-phenoxymethylbenzothiazole (3f), 6-nitro-2-(2-methoxyphenyl)benzoxazole (1a), 5-methylcarboxylate-2-phenylthiomethylbenzimidazole (3c), and 6-methyl-2-(2-nitrophenyl)benzoxazole (1c) were found to be more active than the reference drug etoposide. Present results point out that, besides the very well-known bi- and ter-benzimidazoles, compounds with single bicycle fused ring systems in their structure such as benzimidazole, benzoxazole, benzothiazole, and/or oxazolopyridine derivatives also exhibit significant topoisomerase II inhibitory activity.
