Brown Iain, Shalli Kawan, McDonald Sarah L, Moir Susan E, Hutcheon Andrew W, Heys Steven D, Schofield Andrew C
Department of Surgery, University of Aberdeen, Medical School, Aberdeen, UK.
Breast Cancer Res. 2004;6(5):R601-7. doi: 10.1186/bcr918. Epub 2004 Aug 5.
Docetaxel is one of the most effective chemotherapeutic agents in the treatment of breast cancer. Breast cancers can have an inherent or acquired resistance to docetaxel but the causes of this resistance remain unclear. However, apoptosis and cell cycle regulation are key mechanisms by which most chemotherapeutic agents exert their cytotoxic effects.
We created two docetaxel-resistant human breast cancer cell lines (MCF-7 and MDA-MB-231) and performed cDNA microarray analysis to identify candidate genes associated with docetaxel resistance. Gene expression changes were validated at the RNA and protein levels by reverse transcription PCR and western analysis, respectively.
Gene expression cDNA microarray analysis demonstrated reduced p27 expression in docetaxel-resistant breast cancer cells. Although p27 mRNA expression was found to be reduced only in MCF-7 docetaxel-resistant sublines (2.47-fold), reduced expression of p27 protein was noted in both MCF-7 and MDA-MB-231 docetaxel-resistant breast cancer cells (2.83-fold and 3.80-fold, respectively).
This study demonstrates that reduced expression of p27 is associated with acquired resistance to docetaxel in breast cancer cells. An understanding of the genes that are involved in resistance to chemotherapy may allow further development in modulating drug resistance, and may permit selection of those patients who are most likely to benefit from such therapies.
多西他赛是治疗乳腺癌最有效的化疗药物之一。乳腺癌可能对多西他赛具有内在或获得性耐药性，但其耐药原因尚不清楚。然而，细胞凋亡和细胞周期调控是大多数化疗药物发挥细胞毒性作用的关键机制。
我们构建了两种对多西他赛耐药的人乳腺癌细胞系（MCF-7和MDA-MB-231），并进行了cDNA微阵列分析，以鉴定与多西他赛耐药相关的候选基因。分别通过逆转录PCR和蛋白质印迹分析在RNA和蛋白质水平验证基因表达变化。
基因表达cDNA微阵列分析表明，多西他赛耐药的乳腺癌细胞中p27表达降低。虽然仅在MCF-7多西他赛耐药亚系中发现p27 mRNA表达降低（2.47倍），但在MCF-7和MDA-MB-231多西他赛耐药的乳腺癌细胞中均观察到p27蛋白表达降低（分别为2.83倍和3.80倍）。
本研究表明，p27表达降低与乳腺癌细胞对多西他赛的获得性耐药相关。了解参与化疗耐药的基因可能有助于进一步开发调节耐药性的方法，并可能有助于选择最有可能从此类治疗中获益的患者。
