title: Arsenic trioxide prevents radiation-enhanced tumor invasiveness and inhibits matrix metalloproteinase-9 through downregulation of nuclear factor kappaB.
abstract: Arsenic trioxide (ATO) has been implicated as a promising anticancer agent by inhibiting cell growth and inducing apoptosis in certain types of cancer cells. This study explored the antimetastasis property of arsenic, drew potential link between arsenic use and radiotherapy, and uncovered the specific mechanisms underlying these remarkable responses. Using gelatin invasion assay and intravasation assay, we report the novel finding that low-dose ATO (1 muM) reduced the intrinsic migration ability of HeLa cells and significantly inhibited radiation-promoted tumor invasive potential of CaSki cells without inducing apoptotic cell death. Using the murine Lewis lung carcinoma model, the control animals and ATO treatment animals (1 mg/kg i.p., twice weekly) displayed similar in vivo growth kinetics, whereas the radiation (30 Gy in one fraction) and concurrent treatment groups showed considerable growth inhibition. Importantly, although concurrent treatment did not enhance the effectiveness of radiation therapy to the primary tumor, further examination of the lungs revealed that all animals succumbed to radiation-accelerated lung metastases could be effectively treated by combination of ATO and radiation. Radiation-induced matrix metalloproteinase-9 (MMP-9) expression was significantly inhibited by ATO using sequential analysis of the expression of MMPs in xenografts. Supporting this observation, ATO directly downregulates radiation-induced MMP-9 mRNA expression by inhibiting nuclear factor kappaB activity in human cervical cancer cells. In sum, concurrent arsenic-radiation therapy not only achieves local tumor control but also inhibits distant metastasis. Experimental results of this study highlight a novel strategy in cancer treatment.
authors.affiliation: Department of Oncology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Lin-Hung
authors.initials: LH
authors.lastname: Wei
authors.forename: Kuo-Pao
authors.initials: KP
authors.lastname: Lai
authors.forename: Chi-An
authors.initials: CA
authors.lastname: Chen
authors.forename: Chia-Hsien
authors.initials: CH
authors.lastname: Cheng
authors.forename: Yun-Ju
authors.initials: YJ
authors.lastname: Huang
authors.forename: Chia-Hung
authors.initials: CH
authors.lastname: Chou
authors.forename: Min-Liang
authors.initials: ML
authors.lastname: Kuo
authors.forename: Chang-Yao
authors.initials: CY
authors.lastname: Hsieh
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D000077237:Arsenic Trioxide; D001152:Arsenicals / Q000494:pharmacology*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005720:Gamma Rays; D015972:Gene Expression Regulation, Neoplastic; D017930:Genes, Reporter; D006367:HeLa Cells; D006801:Humans; D020780:Matrix Metalloproteinase 9 / Q000235:genetics* / Q000528:radiation effects; D061965:Matrix Metalloproteinase Inhibitors; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism*; D009361:Neoplasm Invasiveness / Q000517:prevention & control*; D010087:Oxides / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000970:Antineoplastic Agents; D001152:Arsenicals; D004791:Enzyme Inhibitors; D061965:Matrix Metalloproteinase Inhibitors; D016328:NF-kappa B; D010087:Oxides; D020780:Matrix Metalloproteinase 9; D000077237:Arsenic Trioxide