Tumor cells resistant to a microtubule-depolymerizing hemiasterlin analogue, HTI-286, have mutations in α- or β-tubulin and increased microtubule stability
Tumor cells resistant to a microtubule-depolymerizing hemiasterlin analogue, HTI-286, have mutations in α- or β-tubulin and increased microtubule stability
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DOI：
10.1021/bi049300
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发表时间：
2004-11-09
期刊：
影响因子：
2.9
通讯作者：
Fojo, T
中科院分区：
文献类型：
--
作者：
Poruchynsky, MS;Kim, JH;Fojo, T
Hemiasterlin是海绵衍生的三肽，其通过解聚现有微管和抑制微管组装来抑制细胞生长。由于hemiasterlin是P-糖蛋白的不良底物，因此它们是用于癌症治疗的有吸引力的候选物，并且已经进行了临床试验。在HTI-286中选择的卵巢癌（A2780/1A 9）细胞衍生的细胞群中检查了对哈米特林合成类似物HTI-286（HTI）的耐药性基础。1A 9-HTI抗性细胞（1A 9-HTIR系列）对HTI的抗性为57-89倍。观察到对其他微管蛋白解聚药物的交叉耐药（3-186倍），对微管蛋白聚合剂具有间接敏感性（2-14倍）。1A 9亲本和1A 9-HTIR细胞中聚合和可溶性微管蛋白百分比的评价证实了HTI细胞毒性数据。在22 ℃或37 ℃下，在没有任何药物的情况下，每个1A 9-HTIR群体的聚合微管的百分比大于1A 9亲本细胞中的聚合微管的百分比，这与更稳定的微管一致。此外，1A 9-HTIR群体中的微管在4 ℃下对解聚的抗性也更强，并且具有更多的乙酰化和脱酪氨酸（Glu-微管蛋白）α-微管蛋白，所有这些都是更稳定的微管的特征。1A 9-HTIR细胞群在M40 β-微管蛋白同种型S172 A中表现出单核苷酸变化，或在未检测到β-微管蛋白突变的两个细胞群中表现出突变，在一个耐药细胞群中表现出Ka-1 α-微管蛋白同种型S165 P和R221 H，在另一个耐药细胞群中表现出1384 V。与导致药物亲和力降低的突变的报道不同，实验数据和突变的位置与β-或α-微管蛋白中微管稳定突变介导的对HTI-286的抗性一致。
Hemiasterlins are sponge-derived tripeptides that inhibit cell growth by depolymerizing existing microtubules and inhibiting microtubule assembly. Since hemiasterlins are poor substrates for P-glycoprotein, they are attractive candidates for cancer therapy and have been undergoing clinical trials. The basis of resistance to a synthetic analogue of hemiasterlin, HTI-286 (HTI), was examined in cell populations derived from ovarian carcinoma (A2780/1A9) cells selected in HTI-286. 1A9-HTI-resistant cells (1A9-HTIR series) were 57-89-fold resistant to HTI. Cross-resistance (3-186-fold) was observed to other tubulin depolymerizing drugs, with collateral sensitivity (2-14-fold) to tubulin polymerizing agents. Evaluation of the percentage of polymerized and soluble tubulin in 1A9 parental and 1A9-HTIR Cells corroborated the HTI cytotoxicity data. At 22 degreesC or 37 degreesC, in the absence of any drug, the percentage of polymerized microtubules for each of the 1A9-HTIR populations was greater than that in the 1A9 parental cells, consistent with more stable microtubules. Furthermore, microtubules in the 1A9-HTIR populations were also more resistant to depolymerization at 4 degreesC and had more acetylated and detyrosinated (Glu-tubulin) alpha-tubulin, all characteristic of more stable microtubules. The 1A9-HTIR cell populations exhibited either a single nucleotide change in the M40 beta-tubulin isotype, S172A, or in two cell populations where no beta-tubulin mutation was detected, mutations in the Kalpha-1 alpha-tubulin isotype, S165P and R221H in one resistant cell population and 1384V in another. Unlike reports of mutations resulting in reduced drug affinity, the experimental data and location of mutations are consistent with resistance to HTI-286 mediated by microtubule-stabilizing mutations in beta- or alpha-tubulin.