砷化物是一個普遍存在的環境致癌物質，而且其毒性機制卻尚未完全瞭解。於此篇研究中，我們探討Gal-1蛋白與亞砷酸鈉毒性與作用機制。Gal-1於細胞的增生、細胞與基質間交互作用以及自發性死亡皆扮演一個很重要的角色，但是目前尚未有亞砷酸鈉與Gal-1的研究。以反轉錄聚合酶鏈反應與西方點墨法證明亞砷酸鈉會抑制中國倉鼠卵巢細胞及中度抗砷細胞的Gal-1的表現量呈現處理劑量與時間關係；而在另外兩種人類口腔上皮癌細胞與老鼠纖維母細胞內的Gal-1的表現量亦受亞砷酸鈉所抑制。以SRB分析方法得知Gal-1轉殖細胞株（KB-gal與3T3-gal）對亞砷酸鈉比較敏感。以試管實驗與細胞內實驗證實亞砷酸鈉會直接與Gal-1蛋白所鍵結。砷化物對蛋白質的硫醇基有高度的親和性，未來以定位點突變找出galectin-1與亞砷酸鈉鍵結的正確位置。 Arsenic is a ubiquitous environmental carcinogen, and its toxic mechanism is not fully illustrated. In this, we study the role of galectin-1 in arsenite-induced toxicity. Though galectin-1 plays important role in cell proliferation, cell-matrix interaction and apoptosis, the association of galectin-1 with sodium arsenite has never been reported. Our present result showed that the expression of galectin-1 was dose- and time-dependently inhibited by sodium arsenite treatment in CHOA (Chinese hamster ovary cells) and SA7N cells (a revertant of SA7 cells cultured in arsenite-free medium) as indicated by RT-PCR and Western blot. The protein level of galectin-1 was also inhibited by sodium arsenite treatment in KB and 3T3 cell. The galectin-1-transfected KB and 3T3 cells showed more sensitive to arsenite treatment. The current results also suggest that sodium arsenite could bind directly to galectin-1 by in vitro and in vivo binding assay. Arsenite has been proposed with high affinity for sulfhydryl groups of protein. Site-directed mutagesis in cysteine residues of galectin-1 are currectly underway to further idently the binding site of galectin-1 with arsenite.