Study on the antitumor arug resistance in oral squamous carcinoma cells-Analysis of resistance mechanism and development of therapy for overcoming o the resistance-

本研究的目的是通过使用未经放疗和/或化疗的口腔鳞状细胞癌患者的癌细胞分离来分析抗肿瘤药物耐药的机制，从而开发克服耐药的治疗方法。结果如下：1）15例鳞状细胞癌患者的临床标本经裸鼠异种移植后分离出癌细胞，其中10例来自未经治疗的原发灶或转移淋巴结，3例来自放疗后原发灶或转移淋巴结，2例来自放化疗后复发灶。不同肿瘤对博莱霉素的敏感性不同，但大多数放化疗后分离的肿瘤对抗癌药物的敏感性较低32例临床标本和6例培养肿瘤细胞中2例单克隆抗体免疫组化染色显示多药耐药基因产物P-糖蛋白阳性，C219，但Western blotting均未检测到蛋白条带（25倍耐药）对CBDCA、BLM、MMC和5-FU的敏感性降低2倍以上。尽管这种耐药细胞与KB细胞之间的细胞内谷胱甘肽浓度没有差异，通过免疫染色和蛋白质印迹，抗性细胞显示与KB细胞相比仅三分之一的细胞内CDDP浓度和升高的HSP 27和70（应激蛋白）表达。4）与THP-ADM联合化疗的抗肿瘤作用，CDDP和5-FU使用裸鼠肿瘤（包括多药耐药细胞）进行检测。结果表明，THP-ADM、5-FU和CDDP的给药顺序优于THP-ADM、CDDP和5-FU。与合成类异戊二烯的组合增加了BLM的效果。

The aim of this study is to analyze the mechanism of antitumor drug resistance by using carcinoma cells isolated from oral squamous cell carcinoma patients without and with irradiation and/or chemotherapy and thereby to develop the therapy for overcoming of the resistance. The results obtained are as follows.1) Squamous cell carcinoma cells were isolated from fifteen patients by heterotransplantation of clinical specimens to nude mice : 10 cases from untreated primary lesions or metastasized lymph nodes, 3 cases from primary lesions or metastasized lymph nodes after irradiation, 2 cases from recurrent lesions after irradiation and chemotherapy. Each tumor showed a different sensitivity to bleomycin, but most of the tumors isolated after irradiation and chemotherapy showed a low sensitivity to antitumor agents.2) Five cases in 15 cases (32 specimens) of clinical materials and 2 cases in 6 cases of cultured tumor cells showed a positive staining forP-glycoprotein, a multidrug resistance gene product, in immuno-histochemical staining with monoclonal antibody, C219.However, , protein bands by Western blotting were out demonstrated in any case.3) The CDDP-resistant KB carcinoma cells isolated in vitro (25-fold degree of resistance) were over two-fold less sensitive kto CBDCA,BLM,MMC and 5-FU,Although there was no difference in intracellular glutathione concentration between this resistant cells and KB cells, resistant cells showed only one third of the intracellular CDDP concentration and elevated expression of HSP 27 and 70, stress proteins, by immunostaining and Western blotting, as compared to KB cells.4) Antitumor effect of combination chemotherapy with THP-ADM,CDDP and 5-FU was examined using nude mouse tumors including multidrug resistant celsl. As a results, THP-ADM,5-FU and CDDP was more effective than THP-ADM,CDDP and 5-FU in the sequence of administration. The combination with synthetic isoprenoid increased the effect of BLM.