Functional characterization of 2q22.1 deletion in oral squamous cell carcinoma

项目总结/摘要 口腔鳞状细胞癌（OSCC）影响全世界约35万患者。主要原因 口腔鳞状细胞癌包括吸烟、饮酒和感染高危人群。 乳头瘤病毒（HPV）。目前，提供给患者的主要治疗方式包括手术，放射， 化疗和免疫疗法。尽管现有的临床干预措施，这种疾病的死亡率 保持约20%，并且对于更高级别的肿瘤更高。口腔鳞状细胞癌肿瘤是遗传异质性的 具有高的点突变率和体细胞拷贝数变异（CNVs）。类似的CNV模式是 通常在其他鳞状细胞癌中观察到，例如来自肺、子宫颈的鳞状细胞癌， 食道CNV还具有与肿瘤细胞的失活突变共同发生的高倾向性。 抑制基因然而，尽管发现记录了各种基因组位点的存在， 拷贝数的改变，这些CNV对OSCC致癌作用的机制还有待进一步研究。 测定口腔鳞状细胞癌早期和最常见的遗传改变包括肿瘤抑制基因的丢失 CDKN 2A（位于9 p）与TP 53（位于17 p）中的突变结合。此外，最 OSCC肿瘤中常见的缺失位点位于2q22.1。删除的内容完全包含在 低密度脂蛋白受体相关蛋白1B基因，LRP 1B，与肿瘤有关 在其他癌症中是抑制因子，但在OSCC中尚未表征。虽然在这个位点发生缺失， 这种基因内的失活点突变并不常见，其发生率比预期的偶然性要高。 此外，LRP 1B在口腔角质形成细胞中不表达，这就提出了一个问题，即为什么在该位点的缺失 以如此高的频率发生，尽管缺乏基因表达。这表明这些缺失是通过 该机制与干扰LRP 1B功能无关。因此，我假设染色体 2q22.1的缺失通过改变基因内元件， 在肿瘤抑制中的作用。这个建议将通过三个具体目标来解决我的假设：1）确定 2q22.1染色体缺失对体外角质形成细胞致瘤行为的影响，2）鉴定 负责肿瘤发生行为的2q22.1缺失下游机制，和3）确定最小的 负责观察到的表型变化的关键区域。这些目标将通过一个 生物化学和分子生物学技术的组合，以产生在患者样品中观察到的缺失 在野生型角质形成细胞中，并评估它们对肿瘤发生行为的贡献。调查结果 将用于开发抑制OSCC的新型治疗应用， 源自鳞状上皮的其他癌症。

PROJECT SUMMARY/ABSTRACT Oral squamous cell carcinoma (OSCC) affects approximately 350,000 patients worldwide. The primary causes of OSCC include smoking, consumption of alcoholic beverages, and infections with high-risk human papillomaviruses (HPV). Currently, the main therapeutic modalities offered to patients include surgery, radiation, chemotherapy, and immunotherapy. Despite the existing clinical interventions, the mortality for this disease remains approximately 20% and is greater for higher grade tumors. OSCC tumors are genetically heterogenous with a high rate of point mutations and somatic copy number variations (CNVs). Similar CNV patterns are commonly observed in other squamous cell carcinomas such as those arising from the lung, cervix, and esophagus. The CNVs also have a high propensity for co-occurring with inactivating mutations of tumor suppressor genes. However, despite discoveries documenting the presence of various genomic loci undergoing copy number alterations, the mechanistic contributions of these CNVs to OSCC carcinogenesis have yet to be determined. The early and most frequent genetic alterations in OSCC include loss of tumor suppressors CDKN2A (residing at 9p) in conjunction with mutations in TP53 (residing at 17p). Additionally, one of the most commonly deleted sites within OSCC tumors is located at 2q22.1. This deletion is entirely contained within the low-density lipoprotein receptor-related protein 1B gene, LRP1B, which has been implicated as a tumor suppressor in other cancers but has not been characterized in OSCC. Although deletions at this locus occur more frequently than would be expected by chance, inactivating point mutations within this gene are not common. Moreover, LRP1B is not expressed in oral keratinocytes, raising the question as to why the deletions at this locus occur at such a high frequency, despite the lack of gene expression. This suggests these deletions act by a mechanism that is independent of interfering with LRP1B function. Therefore, I hypothesize that chromosomal deletions at 2q22.1 act as driver events in OSCC progression via alteration of intragenic elements that function in tumor suppression. This proposal will address my hypothesis via three specific aims: 1) Determine the impact of 2q22.1 chromosomal deletions on the tumorigenic behavior of keratinocytes in vitro, 2) Identify mechanisms downstream of 2q22.1 deletion responsible for tumorigenic behavior, and 3) Identify the minimal critical region responsible for the observed phenotypic changes. These aims will be achieved utilizing a combination of biochemical and molecular biology techniques to create the deletions observed in patient samples in wild type keratinocytes and assess their contribution to tumorigenic behavior. Outcomes from this investigation will be used in the development of novel therapeutic applications for suppression of OSCC and potentially various other cancers that originate from the squamous epithelium.