Department of Urology, Tufts Medical Center/Tufts University School of Medicine, Boston, MA, USA.
Cancer Biol Ther. 2011 Jan 15;11(2):204-12. doi: 10.4161/cbt.11.2.13750.
The molecular mechanisms conferring resistance to docetaxel in prostate cancer patients remain partially understood. We generated docetaxel resistant derivatives of the androgen independent prostate cancer cell lines PC-3 and DU-145. Docetaxel rapidly induces DU-145 cell death via apoptosis and the drug resistant cells were produced by periodically exposing proliferating DU-145 cultures to small doses of docetaxel. In PC-3 cells docetaxel induces delayed cell death via mitotic catastrophe evident by profound multinucleation and formation of giant cells. Mononucleated progeny of the giant PC-3 cells shows significant resistance to docetaxel. Gene expression profiling of these docetaxel resistant PC-3 cells revealed sets of docetaxel inducible and constitutively expressed genes associated with major cancer pathways. A contradictory overlap with DU-145 docetaxel resistant cells was also found. Analyses suggested significant changes associated with apoptotic function, DNA repair, cell growth, survival and proliferation, metabolism, maintenance of cytoskeleton and extracellular matrix formation. These cellular processes often contribute to drug resistance and our study identified a set of genes managing this phenotype. Additional analyses of the drug resistant PC-3 cells using shRNA constructs determined direct relevance of Cyclin G2 to docetaxel resistance as well as prevention of multinucleation, whereas the knockdown of upregulated CYP1B1 showed no effect on either of these processes. Downregulated GBP1 was explored by ectopic overexpression and even though GBP1 has a potential to mediate resistance to docetaxel, it was not utilized in PC-3 cells. The results suggest complex combination of gene expression pattern changes that enables resistance to docetaxel while preventing death via multinucleation.
在前列腺癌患者中，赋予对多西紫杉醇耐药的分子机制仍部分了解。我们生成了雄激素非依赖性前列腺癌细胞系 PC-3 和 DU-145 的多西紫杉醇耐药衍生物。多西紫杉醇通过凋亡迅速诱导 DU-145 细胞死亡，耐药细胞是通过周期性地将增殖的 DU-145 培养物暴露于小剂量的多西紫杉醇来产生的。在 PC-3 细胞中，多西紫杉醇通过有丝分裂灾难诱导延迟的细胞死亡，明显表现为多极核和巨细胞的形成。巨 PC-3 细胞的单核后代对多西紫杉醇表现出显著的耐药性。对这些多西紫杉醇耐药的 PC-3 细胞进行基因表达谱分析，揭示了与主要癌症途径相关的多西紫杉醇诱导和组成性表达基因。还发现与 DU-145 多西紫杉醇耐药细胞存在矛盾重叠。分析表明与凋亡功能、DNA 修复、细胞生长、存活和增殖、代谢、细胞骨架和细胞外基质形成的维持相关的显著变化。这些细胞过程通常与耐药性有关，我们的研究确定了一组管理这种表型的基因。使用 shRNA 构建体对耐药性 PC-3 细胞的进一步分析确定了细胞周期蛋白 G2 与多西紫杉醇耐药直接相关，以及预防多核化，而上调的 CYP1B1 的敲低对这两种过程均无影响。通过异位过表达探索下调的 GBP1，尽管 GBP1 具有介导多西紫杉醇耐药的潜力，但它未在 PC-3 细胞中被利用。结果表明，复杂的基因表达模式变化组合使细胞能够耐受多西紫杉醇，同时防止通过多核化导致的死亡。
