Department of Basic Pharmaceutical Sciences, University of Louisiana at Monroe, Monroe, LA 71209, USA.
Biochem Pharmacol. 2010 Jul 1;80(1):72-9. doi: 10.1016/j.bcp.2010.03.010. Epub 2010 Mar 16.
Multidrug resistance is a major impediment to the success of cancer chemotherapy. The overproduced P-glycoprotein that extrudes anticancer drugs from cells, is the most common mechanism detected in multidrug-resistant cancers. Direct measurement of cellular efflux of tumors in vivo, rather than estimation of MDR1 mRNA and P-glycoprotein levels in samples stored or embedded, can functionally characterize the mechanism of drug resistance and determine the choice of anticancer drugs for cancer patients. Herewith, we introduce a new approach to directly determine P-glycoprotein efflux of tumors. Employing Flutax-2 (Oregon green-488 paclitaxel) and fluorescence spectrophotometry, this method has successfully measured cellular transportability including efflux and accumulation in diverse cancer cell lines, tumors and other tissues with high reproducibility. With this method, we have quantitatively determined cellular efflux that is correlated with P-glycoprotein levels and the reversal effects of agents in cell lines of breast, ovarian, cervical and colon cancers, and in tumor-bearing mice. It has sensitively detected these alterations of P-glycoprotein efflux in approximately 5mg tumor or other tissues with high confidence. This direct and quick functional assessment has a potential to determine drug resistance in different types of cancers after surgical resection. Further validation of this method in clinic settings for the diagnosis of drug resistance purpose is needed.
多药耐药性是癌症化疗成功的主要障碍。过度表达的 P-糖蛋白将抗癌药物从细胞中排出，是在多药耐药性癌症中检测到的最常见机制。直接测量体内肿瘤的细胞外排，而不是估计储存或嵌入样本中的 MDR1 mRNA 和 P-糖蛋白水平，可以功能表征耐药机制，并为癌症患者确定抗癌药物的选择。在此，我们介绍了一种直接测定肿瘤 P-糖蛋白外排的新方法。该方法采用 Flutax-2（Oregon green-488 紫杉醇）和荧光分光光度法，成功测量了包括乳腺癌、卵巢癌、宫颈癌和结肠癌细胞系、肿瘤和其他组织在内的多种细胞的转运能力，具有高度的重现性。使用该方法，我们定量测定了与 P-糖蛋白水平相关的细胞外排率以及在乳腺癌、卵巢癌、宫颈癌和结肠癌细胞系以及荷瘤小鼠中的药物的逆转作用。它能够高度自信地灵敏检测约 5mg 肿瘤或其他组织中 P-糖蛋白外排的这些改变。这种直接快速的功能评估有可能在手术切除后确定不同类型癌症的耐药性。需要在临床环境中进一步验证该方法用于耐药性诊断的目的。
