Prostate, 2011, 71(16):1810–1817.

Chemotherapy Sensitivity Recovery of Prostate Cancer Cells by Functional Inhibition and Knock Down of Multidrug Resistance Proteins

Catherine Sanchez, et al.

Laboratory of Molecular and Cellular Andrology, Physiology and Biophysics Department, Faculty of Medicine, University of Chile, Santiago, Chile; Urology Service,Clinical Hospital Universityof Chile, Santiago,Chile

BACKGROUND: In several cancer types, expression of multidrug resistance (MDR) proteins has been associated with lack of chemotherapy response. In advanced prostate cancer (PCa) the use of chemotherapy is mainly palliative due to its high resistance. Previously, we described that MDR phenotype in PCa could be related with high basal and drug-induced expression of MDR proteins P-Glycoprotein (P-Gp), MRP1, and LRP.

METHODS: Using primary cell cultures from PCa patients, we evaluated the effect of function and expression inhibition of P-Gp, MRP1, and LRP, on cell survival after chemotherapy exposure. Cells were treated with specific MDR protein substrates (docetaxel and mitoxantrone for P-Gp, methotrexate for MRP1 and cisplatin for LRP) and pharmacological inhibitors (cyclosporine A, genistein and 3-aminobenzamide), and cell survival was evaluated trough 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and cell cycle analysis. MRP1 activity was evaluated by FACS using the specific inhibitor MK571. Cells were transfected with MDR proteins siRNAs and treated with the corresponding substrates.

RESULTS: PCa cell resistance to MDR protein substrates was partially reversed, decreasing cell survival in around 20%, by treating primary cell cultures with specific pharmacological inhibitors. PCa cells transfected with siRNAs against MDR proteins decreased cell survival when treated with the corresponding drugs. Docetaxel was the most effective chemotherapeutic drug to induce cell death and decrease survival.

CONCLUSION: Low chemotherapy response in PCa could be explained, in part, by over-expression of functional MDR proteins. Expression and function of these proteins should be evaluated to enhance efficacy of docetaxel-based therapies of patients with hormone-resistant PCa.

美国《前列腺癌》，2011年4月

通过对多药耐药蛋白的功能性抑制和打击来恢复前列腺癌细胞的化疗敏感性

凯瑟琳  桑切斯等

智利大学医学院生理学和生物物理学系分子和细胞男性生殖病学实验室；智利大学临床医院泌尿外科服务部

背景︰ 在几种癌症类型中，多药耐药 (MDR) 蛋白的表达与化疗反应的不足相关联。在中晚期前列腺癌 (PCa)由于高抗性减轻化疗的使用。以前，我们描述了多药耐药在 PCa 中的表型与高基底和 MDR 蛋白 P-糖蛋白 (P-Gp)、 MRP1 和LPR的药物诱导表达有关。

方法︰ 从 PCa 病人中提取基本细胞培养基，我们评估了在化疗以后P-Gp、 MRP1 和LRP的功能及表达抑制对细胞存活的效果。用特定的MDR底物 （用于P-Gp的多西他赛和 盐酸米托蒽醌，用于MRP1的 甲氨蝶呤和用于 LRP的 顺铂）和药理性抑制剂 （环孢菌素 A、 金雀异黄素和 3-氨戊酰胺）处理细胞，通过MTT 法和细胞周期分析计算细胞的存活率。使用特异性抑制剂MK571通过FACS评估 MRP1的活性。用MDR蛋白 siRNA 转录细胞并用相应底物处理。

结果︰ PCa 细胞对MDR蛋白底物的抗性被部分逆转，降低了 20%左右的细胞存活率，通过用特定的药理抑制剂治疗基本细胞培养基。在被相关药物治疗时转录了抗MDR蛋白的siRNA的PCa 细胞降低了细胞存活率。多西他赛是目前最有效的诱导细胞死亡和降低存活率的化疗药物。

结论︰在 PCa中低的化疗反应可以用功能性MDR蛋白的过度表达来部分的解释。这些蛋白质的表达和功能被评估用来提高以多西他赛为基础的疗法对耐激素PCa患者的功效。