Akakura K, Bruchovsky N, Rennie P S, Coldman A J, Goldenberg S L, Tenniswood M, Fox K
Department of Cancer Endocrinology, British Columbia Cancer Agency, Vancouver, Canada.
J Steroid Biochem Mol Biol. 1996 Dec;59(5-6):501-11. doi: 10.1016/s0960-0760(96)00132-x.
The proportion of tumorigenic stem cells and the expression of the apoptosis-related gene, TRPM-2 (clusterin), were studied in populations of Shionogi carcinoma cells subjected to multiple cycles of androgen withdrawal and replacement (intermittent androgen suppression). The parent androgen-dependent cell line was initially transplanted into a male mouse which was castrated when the estimated weight of the resultant tumour became approximately 3 g. After the tumour had regressed to 40% or less of the original weight, it was transplanted into the next non-castrated male. This was repeated for four cycles of transplantation and castration-induced apoptosis before the tumour progressed to an androgen-independent state. The proportion of total stem cells in the tumour, as determined by in vivo limiting dilution assays in male mice, was constant during the first three cycles but increased 15-fold between the third and fourth cycles. In the parent androgen-dependent tumour before androgen ablation, the androgen-independent stem cell population formed 0.8% of the total stem cell compartment. After the fourth cycle this population increased to 47%; a population of similar size (33%, P = 0.8) was found in the androgen-independent recurrent form of the tumour induced by one-time castration. Whether androgen withdrawal therapy was intermittent or continuous, conversion to androgen independence thus occurred when one-third to one-half of the total stem cell compartment was populated by androgen-independent stem cells. The androgen-repressed TRPM-2 (clusterin) gene was actively expressed in regressing tumours after androgen ablation, and also became constitutively expressed in non-regressing tumours after the first and subsequent cycles of androgen withdrawal. Staining of cytoplasm and nuclei with anti-clusterin antibody was observed in androgen-dependent tumour cells after each cycle of intermittent androgen suppression; the nuclear staining was more intense in recurrent androgen-independent cells. The anomalous nuclear localization of clusterin, an anti-cytolytic TRPM-2 encoded protein, may serve to inhibit early events in the apoptotic process and thereby foster the generation and outgrowth of androgen-independent stem cells in an androgen-depleted environment.
研究了在经受多次雄激素撤除和替代循环（间歇性雄激素抑制）的狮王（Shionogi）癌细胞群体中致瘤干细胞的比例以及凋亡相关基因TRPM-2（聚集素）的表达。将亲本雄激素依赖性细胞系最初移植到雄性小鼠体内，当所形成肿瘤的估计重量达到约3 g时对该小鼠进行去势。在肿瘤消退至原始重量的40%或更低后，将其移植到下一只未去势的雄性小鼠体内。在肿瘤进展为雄激素非依赖性状态之前，重复进行四个移植和去势诱导凋亡的循环。通过雄性小鼠体内有限稀释分析确定，肿瘤中总干细胞的比例在前三个循环中保持恒定，但在第三个和第四个循环之间增加了15倍。在雄激素切除前的亲本雄激素依赖性肿瘤中，雄激素非依赖性干细胞群体占总干细胞区室的0.8%。在第四个循环后，该群体增加到47%；在一次性去势诱导的肿瘤的雄激素非依赖性复发形式中发现了大小相似的群体（33%，P = 0.8）。因此，无论雄激素撤除疗法是间歇性还是连续性的，当总干细胞区室的三分之一到二分之一由雄激素非依赖性干细胞占据时，就会发生向雄激素非依赖性的转变。雄激素抑制的TRPM-2（聚集素）基因在雄激素切除后的消退肿瘤中活跃表达，并且在第一次及随后的雄激素撤除循环后的非消退肿瘤中也持续表达。在间歇性雄激素抑制的每个循环后，在雄激素依赖性肿瘤细胞中观察到用抗聚集素抗体对细胞质和细胞核的染色；在复发的雄激素非依赖性细胞中核染色更强烈。聚集素是一种抗细胞溶解的TRPM-2编码蛋白，其异常的核定位可能有助于抑制凋亡过程中的早期事件，从而促进在雄激素缺乏环境中雄激素非依赖性干细胞的产生和生长。
