Modulation of Human Cancer Cell Lines to Mitomycin C Susceptibility by Sodium Arsenite Pretreatment

• Main Authors: Yii-Ling Lin, 林依玲
• Other Authors: Te-Chang Lee
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/18958801450118713256

碩士 === 國立陽明大學 === 藥理學研究所 === 91 === Arsenic has been extensively used in medicine for a long time. In recent years, therapy with arsenic trioxide offers the opportunity for a complete remission and improved survival in patients with refractory or relapsed acute promyelocytic leukemia (APL). However, therapy with arsenic in sold tumors is still on clinical trials. Mechanisms of arsenic action in cancer therapy include induction of cytodifferentiation, apoptosis, and inhibition of cell proliferation and angiogenesis, etc. The objective of this study attempts to find suitable target genes altered by arsenic and to establish an effective cancer therapy protocol for other cancers. In a preliminary cDNA microarray study in our laboratory, NAD(P)H quinone oxidoreductase 1 (NQO1), glutathione peroxidase 2 (GPX2) and heme oxygenase-1 (HO-1) were induced in human lung adenocarcinoma CL3 cells treated with 2 μM sodium arsenite for 24h. In the present study, the enhanced mRNA expression of these genes was further confirmed by Western blot assay. Among these genes, increased protein level and enzyme activity of NQO1 were confirmed by western blot technique and enzymatic activity assay. Since NQO1 is a quinone reductase that physiologically plays an important role on quinone drug metabolism, the influences of the quinone compounds’ cytotoxicity by arsenite via enhanced NQO1 expression were examined by colony forming assay in CL3 cells. Among quinone drugs tested, sodium arsenite pretreatment resulted in increased susceptibility of mitomycin C to CL3 cells but had no obvious influence on susceptibility of adriamycin, menadione and mitoxantrone. Furthermore, dicumarol, a specific inhibitor of NQO1, was shown to abrogate the increased susceptibility of CL3 cells to mitomycin C by arsenite. These results demonstrated the involvement of NQO1 in increased susceptibility to mitomycin C by arsenite pretreatment. To investigate the therapeutic potential of arsenite pretreatment in different cell types, the present results demonstrated that arsenite pretreatment resulted in increased NQO1 activity and susceptibility to mitomycin C in human lung large cell carcinoma H1299 cells and human uroepithelium MC-SV-HUC-1 cells. In contrast, arsenite pretreatment showed neither enhancement of NQO1 expression nor susceptibility to mitomycin C in human lung large cell carcinoma H460 cells. These results revealed that the therapeutic effectiveness of combination of arsenite and mitomycin C in cancer cells that NQO1 expression is enhanced by arsenite pretreatment warrants further animal and clinical trials in the future.