Molecular Targets - Colon Cancer

我们采用了一种新的策略来确定治疗和预防常见癌症的分子靶点，最初的重点是结肠癌。化疗药物的主要局限性之一是相对狭窄的治疗毒性比，这是由于治疗靶点在癌变组织和正常组织中的共性造成的。因此，我们试图通过使用公共数据库中的基因表达信息以及高通量基因表达阵列分析来确定相对癌症特异性的潜在治疗靶点。使用数字基因表达显示器挖掘通过NCI的癌症基因组解剖计划提供的表达文库，我们确定了665个序列在结肠癌文库中表达，但在基本正常组织中不表达。其中，356个基因在Affymetrix表达阵列上得到了表达，这就可以比较这些基因在结肠癌组织和细胞系以及基本正常组织中的表达。这项研究加上随后使用定量RT-PCR的确认，鉴定了两个以前未被表征的基因，它们的表达在大部分结肠癌样本中相对特异性。我们进行了实验，以确定siRNA介导的候选基因的抑制是否抑制HCT15结肠癌细胞系的细胞增殖；使用Cyquant试剂盒进行细胞增殖试验，与siRNA阴性对照相比，抑制细胞增殖10%。siRNA介导的这些基因的沉默导致HCT15细胞系细胞增殖的小幅减少，这表明这些基因可能在促进结肠癌细胞增殖中发挥作用。利用现有数据库与高通量技术相结合的方法来鉴定相对的癌症选择性基因靶点，可能构成一种快速有效的开发活性低毒性化疗药物的方法。这些基因作为潜在靶标的鉴定完全基于它们的表达谱，而不是依赖于它们在细胞内功能的先验知识。除了为药物开发提供感兴趣的靶标之外，这些靶标还可用于药物递送，作为疾病的分子标记，或作为药物递送和药物有效性的替代标记。

We have employed a novel strategy to identify molecular targets for the therapy and prevention of common cancers, with an initial focus on colon cancer. One of the major limitations of chemotherapeutic agents is the relatively narrow therapeutic: toxic ratio that results from the commonality of the therapeutic target in both the cancerous and normal tissues. Therefore, we sought to identify potential therapeutic targets that were relatively cancer specific by using gene expression information available in public databases coupled with the use of high-throughput gene expression array analysis. Using the Digital Gene expression Displayer to mine expression libraries available through the NCI's Cancer Genome Anatomy Project, we identified 665 sequences that were expressed in colon cancer libraries but not in essential normal tissues. Of these, 356 were represented on Affymetrix expression arrays and this allowed for a comparison of the expression of these genes in colon cancer tissues and cell lines, and essential normal tissues. This investigation coupled with subsequent confirmation using quantitative RT-PCR resulted in the identification of two previously uncharacterized genes whose expression was relatively specific to a substantial proportion of colon cancer samples tested. We carried out experiments in order to determine whether the siRNA mediated suppression of our candidate genes inhibits cell proliferation in the HCT15 colon cancer cell line; cell proliferation assays were carried out using a Cyquant kit inhibit cell proliferation by 10% as compared to the siRNA negative control. siRNA mediated silencing of these gene resulted in a small reduction of cell proliferation in HCT15 cell lines indicating that these genes may play a role in promoting cell proliferation in colon cancer. The approach of using available databases coupled with high-throughput technologies for the identification of relatively cancer selective gene targets may constitute a rapid and efficient method for the development of active and less toxic chemotherapeutic agents. The identification of these genes as potential targets was based entirely on their expression profile rather than dependent on prior knowledge of their intracellular function(s). In addition to providing targets of interest for drug development, such targets could also be exploited for drug delivery, as molecular markers of disease, or as surrogate markers for drug delivery and drug effectiveness.