甲基鸟嘌呤甲基转移酶表达调节在肿瘤发生和治疗中的作用

甲基鸟嘌呤甲基转移酶（O⁶-methylguanine-DNA methyltransferase,MGMT）是从细菌到哺乳类机体中存在的一种独特的DNA修复蛋白，其作用是在DNA损伤的修复过程，催化DNA分子鸟嘌呤O⁶位上的烷基从鸟嘌呤碱基转移至MGMT蛋白的半胱氨酸残基上，而使DNA分子鸟嘌呤复原.因此，机体中MGMT适当的表达有利于修复由烷化剂诱导而形成的O⁶烷基鸟嘌呤DNA加合物.MGMT蛋白的含量和活性不但在基因水平受到各种因素的调控，并且与某些药物的直接作用有关.调节MGMT在细胞内的活性，对于防御肿瘤的发生及某些肿瘤的治疗过程中克服肿瘤耐药性和克服骨髓毒性具有重要的意义.

The Action of Regulation on O6-Methylguanine-DNA Methyltransferase Expression in Tumor-geneses and Tumor Therapy

O⁶-methylguanine-DNA methyltransferase (MGMT) is a specific DNA repair protein that exist in cells and tissues from bacteria to mammalias. The function of the repair protein is to catalyzing and transfering the alkyl group from the O⁶ position of guanine of DNA to an internal cysteine residue of MGMT protein which repairs the lesion by reversion the guanine of DNA. Therefore the proper expression of MGMT is useful to repair O⁶-methylguanine-DNA adducts formed by the induction of alkyl agents. The amount and activity of MGMT are not only regulated by various factors at genetic level, but also associated with the directly effects of some drugs. It has important significance to regulate the activity of MGMT in the cells during the prevention of tumor-geneses and overcoming the drug resistance or marrow toxicity.