恶性淋巴瘤细胞株对氨甲蝶呤的耐药性及其机制在化疗个体化中的意义

目的研究恶性淋巴瘤对氨甲蝶呤(MTX)的耐药机制,指导不同类型的恶性淋巴瘤患者合理应用MTX,以期进一步提高疗效并减轻药物毒副反应,改善长期生存质量.方法用MTT法检测了Sup-m2、Namalwa及Namalwa12细胞株对MTX的药效差异,用RT-PCR及3H-MTX掺入结合HPLC法分别检测二氢叶酸还原酶(DHFR)mRNA,还原性叶酸载体(RFC)功能及MTX多聚谷氨酸(MTXPG)各组分含量.结果各细胞株对MTX的敏感程度依次为Sup-m2>Namalwa>Namalwa12;这种差异并非RFC功能不同所致,而与形成MTXPG的量密切相关;Sup-m2细胞不仅较Namalwa细胞形成的MTXPG多,且形成MTXPG的速度也较快;DHFRmRNA表达逐渐增高参与Namalwa12耐药性的形成.结论MTXPG合成不佳、DHFRmRNA表达增高导致Namalwa12Burkitt's恶性淋巴瘤细胞对MTX耐药;大细胞间变性恶性淋巴瘤对MTX高敏,临床MTX使用剂量可相对减少,且维持用药时间也可略缩短.

Resistance and its mechanism of methotrexate against malignant lymphoma cell lines

Purpose:To study on the mechanism of methotrexate (MTX )resistance, so that MTX could be used in variety of malignant lymphomas,in order to reduce side effects of chemotherapy and enhance its effecacy and give the patients a better quality of life for lone term survivors.Methods:MTT drug sensitivity test was used to evaluate the MTX sensitivity in Sup m2,Namalwa and Namalwa 12 cell lines. RT PCR and 3H MTX with HPLC were used to examine the degree of dihydrofolate reductase (DHFR) mRNA expression,reduced folate carrier (RFC) function and polyglutamate MTX ( MTXPG). Results:The orders for MTX sensitivity of various cell lines were observed as follows: Sup m2>Namalwa > Namalwa12. This difference was not the result from differences in RFC function, but from the quantity of MTXPG. Comparing with Namalwa cell line, Sup m2 cell line had the ability not only of producing more MTXPG, but also reaching saturation early. Gradually increased expression of DHFR mRNA was the direct cause of the formation of MTX resistance in Namalwa/MTX cell line. Conclusions:Diminished RFC function, dysformation of MTXPG and overexpresion of DHFR mRNA develop MTX resistance in Namalwa 12 cell line. Patient with large cell anaplastic lymphoma possess high sensitivity to MTX, suggesting that the dosage of MTX may be scaled down, the time of usage may also be shortened.