The Anticancer Effect Of Arsenic Trioxide On Human Nasopharyngeal Cancer Xenografts In Scid Mice

Background and Objective: Arsenic agents have been used as anticancer herbs in traditional Chinese medicine for more than a thousand years. The effective component in the remedy was recently identified as arsenic trioxide (As₂O₃). Long-term clinical trails have shown that As₂O₃ is very effective in the treatment of several types of leukemia, especially acute promyeloid leukemia (APL). Many studies also have investigated the anticancer effect of As₂O₃ in solid cancers including prostate cancer, gastrointestinal cancers and head and neck cancers. However, little is known about the effect of As₂O₃ on nasopharyngeal carcinoma(NPC), a common cancer in south China with nickname of " GUANGDONG cancer". We conduct this study in order to explore the efficacy of Arsenic trioxide (As₂O₃) in the treatment for human NPC xenograft in Scid mouse and its feasibility for further clinical trial. Materials and Methods: Human nasopharyngeal cancer cells from CSNE-1 cell line were implanted subcutaneously into Scid mice to produce tumors. The tumor inhibition rate in vivo was observed after intraperitoneally administering of As₂O₃. The histopathologic change in the tumor tissues, and the toxicity of As₂O₃ to the livers, hearts, lungs, kiddneys and white blood cell counts of the host mice were also investigated.Results: At the dose of 5mg/kg and Img/kg, As₂O₃ induced apoptosis in nasopharyngeal carcinoma cells. As₂O₃ of 5mg/kg also induced the cancer cell differentiation and inhibited tumor growth. No leukopenia was observed at these dose levels but some pathologic changes in liver and cardiac tissue were recognized. It is lethal to the Scid mice at the dose of l0mg/kg. Conclusions: As₂O₃ may have a potential therapeutic effect on NPC at suitable concentration. The mechanism of antitumor activity may be , at least in part, due to the induction of apoptosis and differentiation in cancer cell.