Gheuens E E, van der Heyden S A, Elst H E, Van Oosterom A T, De Bruijn E A
Laboratory for Cancer Research & Clinical Oncology, University of Antwerp, Wilrijk, Belgium.
Cancer Detect Prev. 1997;21(1):78-82.
The detection of multidrug resistance (MDR) in clinical samples is still a topic for discussion. One method, proven extremely useful for detection of membrane proteins in patients with hematological malignancies is the flow cytometrical analysis of individual tumor cells. Recently an assay was described based on the labeling of the P-glycoprotein (P-gp) with the monoclonal antibody MRK16, combined with detection of active daunorubicin (DNR) extrusion. In order to improve the specificity of the assay, on line with the results obtained by Wall et al., we exploited staining with Fluo-3. Both assays prove to be able to discriminate between drug-resistant and drug-sensitive cells. A major drawback of labeling with Fluo-3 in combination with the monoclonal antibody MRK16 is the important overlap of emission spectra of both fluorochromes. Moreover, using Fluo-3 for the detection of MDR might be complicated by the fact that differences in fluorescence intensities are not solely dependent on the presence of P-gp, but also on the activity of cytosolic esterases and the intracellular calcium concentration. Combination of the detection of structural and functional aspects of the MDR-associated protein may lead to a more precise detection of the MDR-positive patient.
临床样本中多药耐药（MDR）的检测仍是一个讨论话题。一种已被证明对检测血液系统恶性肿瘤患者膜蛋白极为有用的方法是对单个肿瘤细胞进行流式细胞术分析。最近描述了一种检测方法，该方法基于用单克隆抗体MRK16标记P-糖蛋白（P-gp），并结合检测柔红霉素（DNR）的主动外排。为了提高检测方法的特异性，根据Wall等人获得的结果，我们采用了Fluo-3染色。这两种检测方法都证明能够区分耐药细胞和药物敏感细胞。Fluo-3与单克隆抗体MRK16联合标记的一个主要缺点是两种荧光染料发射光谱存在重要重叠。此外，使用Fluo-3检测MDR可能会因以下事实而变得复杂：荧光强度差异不仅取决于P-gp的存在，还取决于胞质酯酶的活性和细胞内钙浓度。MDR相关蛋白结构和功能方面检测的结合可能会导致对MDR阳性患者进行更精确的检测。
