Weigum Shannon E, Floriano Pierre N, Christodoulides Nicolaos, McDevitt John T
Department of Chemistry and Biochemistry, The University of Texas at Austin, 1 University Station A5300, Austin, TX 78712, USA.
Lab Chip. 2007 Aug;7(8):995-1003. doi: 10.1039/b703918b. Epub 2007 Jul 11.
Oral cancer is the sixth most common cancer worldwide and has been marked by high morbidity and poor survival rates that have changed little over the past few decades. Beyond prevention, early detection is the most crucial determinant for successful treatment and survival of cancer. Yet current methodologies for cancer diagnosis based upon pathological examination alone are insufficient for detecting early tumor progression and molecular transformation. To address this clinical need, we have developed a cell-based sensor to detect oral cancer biomarkers, such as the epidermal growth factor receptor (EGFR) whose over-expression is associated with early oral tumorigenesis and aggressive cancer phenotypes. The lab-on-a-chip (LOC) sensor utilizes an embedded track-etched membrane, which functions as a micro-sieve, to capture and enrich cells from complex biological fluids or biopsy suspensions. Once captured, "on-membrane" immunofluorescent assays reveal the presence and isotype of interrogated cells via automated microscopy and fluorescent image analysis. Using the LOC sensor system, with integrated capture and staining technique, EGFR assays were completed in less than 10 minutes with staining intensity, homogeneity, and cellular localization patterns comparable to conventional labeling methods. Further examination of EGFR expression in three oral cancer cell lines revealed a significant increase (p < 0.05) above control cells with EGFR expression similar to normal squamous epithelium. Results obtained in the microfluidic sensor system correlated well with flow cytometry (r(2) = 0.98), the "gold standard" in quantitative protein expression analysis. In addition, the LOC sensor detected significant differences between two of the oral cancer cell lines (p < 0.01), accounting for disparity of approximately 34 000 EGFR per cell according to quantitative flow cytometry. Taken together, these results support the LOC sensor system as a suitable platform for rapid detection of oral cancer biomarkers and characterization of EGFR over-expression in oral malignancies. Application of this technique may be clinically useful in cancer diagnostics for early detection, prognostic evaluation, and therapeutic selection. Having demonstrated the functionality of this integrated microfluidic sensor system, further studies using clinical samples from oral cancer patients are now warranted.
口腔癌是全球第六大常见癌症，其发病率高且生存率低，在过去几十年中变化不大。除了预防之外，早期检测是癌症成功治疗和生存的最关键决定因素。然而，目前仅基于病理检查的癌症诊断方法不足以检测早期肿瘤进展和分子转变。为了满足这一临床需求，我们开发了一种基于细胞的传感器来检测口腔癌生物标志物，例如表皮生长因子受体（EGFR），其过度表达与早期口腔肿瘤发生和侵袭性癌症表型相关。芯片实验室（LOC）传感器利用嵌入的径迹蚀刻膜，其作为微筛，从复杂的生物流体或活检悬浮液中捕获和富集细胞。一旦捕获，“膜上”免疫荧光测定通过自动显微镜和荧光图像分析揭示被询问细胞的存在和同种型。使用具有集成捕获和染色技术的LOC传感器系统，EGFR测定在不到10分钟内完成，染色强度、均匀性和细胞定位模式与传统标记方法相当。对三种口腔癌细胞系中EGFR表达的进一步检查显示，与对照细胞相比有显著增加（p < 0.05），EGFR表达与正常鳞状上皮相似。在微流控传感器系统中获得的结果与流式细胞术（r(2) = 0.98）相关性良好，流式细胞术是定量蛋白质表达分析中的“金标准”。此外，LOC传感器检测到两种口腔癌细胞系之间存在显著差异（p < 0.01），根据定量流式细胞术，每个细胞的EGFR差异约为34000。综上所述，这些结果支持LOC传感器系统作为快速检测口腔癌生物标志物和表征口腔恶性肿瘤中EGFR过度表达的合适平台。这项技术的应用在癌症诊断中对于早期检测、预后评估和治疗选择可能具有临床实用性。已经证明了这种集成微流控传感器系统的功能，现在有必要使用口腔癌患者的临床样本进行进一步研究。
