Molecular Drivers of Lung Cancer in Hispanics

项目摘要 肺部恶性肿瘤是西班牙裔/拉丁裔（H/L）男性癌症死亡的主要原因， 在H/L女性中1.虽然H/L已经超过了非洲裔美国人作为少数民族的国家，他们占 只有3%（共149例）的患者在癌症基因组图谱（TCGA）2中进行了特征描述，只有0.4%的患者- 现有的衍生肿瘤学模型3.在肺癌患者中，与白人相比，H/Ls（1） 不吸烟者的死亡率是不吸烟者的两倍4 -8;（2）更常出现晚期疾病7，9;（3） 并且由于缺乏适当的基因组， 肺癌的特征10 -12。为了解决肺癌的这些差异，我们 从H/L患者收集163个肺肿瘤样品并对其进行外显子组测序13。值得注意的是， 观察到的H/L肺腺癌患者KRAS和STK 11突变的患病率非常低， EGFR突变的高流行率--我们13和其他人14发现与土著人相关的一种模式， 美国血统。我们对48例缺乏KRAS或EGFR的患者进行了研究。 RNA测序的驱动突变，以评估已知或未知的融合事件是否可能解释肺 癌症在这个未被充分研究的人群中。在48份患者标本中，10份（21%）具有潜在的 致癌转录物融合。这些患者中有一半（5例）已知MET融合或表达已知 MET的致癌同种型。值得注意的是，其他5例患者标本表达ADCK 4-NUMBL融合， 转录本（三份外显子15：外显子2融合体和两份外显子15：外显子3融合体）。DNA 测序没有揭示基因融合;然而，ADCK 4和NUMBL基因在基因组中头对尾排列。 19号染色体支持ADCK 4（外显子15）与NUMBL（外显子15）基因间顺式剪接的假设， 2)驱动ADCK 4-NUMBL嵌合转录物的表达。类似的转录本在一些 细胞系，但没有观察到大量的RNA测序数据可通过TCGA，这表明，这些 转录物通常仅在H/L患者样品中表达。基于有限的文献15 -18，我们 假设ADCK 4与NUMBL基因间剪接驱动ADCK 4-NUMBL嵌合体的表达 这些转录本表达具有独特生物学特性的癌蛋白。测试这些 假设，我们将1）确定ADCK 4-NUMBL嵌合蛋白表达如何影响细胞 生物学，2）从H/L从不吸烟者建立新的患者来源的细胞系，3）探索 导致顺式剪接的ADCK 2-NUMBL转录物表达的机制。我们预计 这些研究的结果将有助于深入了解肺癌死亡率升高的机制 在不吸烟的H/L中，并确定新的治疗靶点。

Project Summary Lung malignancies are the leading cause of cancer death among Hispanic/Latino (H/L) men and second among H/L women1. While H/L have surpassed African Americans as a minority nationally, they account for only 3% (149 total) of patients characterized in the Cancer Genome Atlas (TCGA)2 and only 0.4% of patient- derived oncological models in existence3. Among lung cancer patients, compared to Caucasians, H/Ls (1) have double the mortality among never-smokers4-8; (2) present more frequently with late-stage disease7, 9; (3) and are often not identified as being candidates for targeted therapy due to the lack of proper genomic characterization of their lung cancers10-12. To address these disparities with respect to lung cancer, we collected 163 lung tumor samples from H/L patients and subjected them to exome sequencing13. Notably, we observed H/L lung adenocarcinoma patients have a very low prevalence of KRAS and STK11 mutations and a high prevalence of EGFR mutations - a pattern that we13 and others14 find associated with Indigenous American ancestry. We subjected 48 patients of those patients from the registry that lacked KRAS or EGFR driver mutations to RNA sequencing to assess if known or unknown fusion-events might account for lung cancer in this understudied population. Out of the 48 patient specimens, ten (21%) harbored potential oncogenic transcript fusions. Half (5) of these patients had known MET fusions or expressed known oncogenic isoforms of MET. Notably, the other five patient specimens expressed ADCK4-NUMBL fusion transcript (three copies of Exon 15: Exon 2 fusions and two copies of Exon 15: Exon 3 fusions). DNA sequencing does not reveal gene fusion; however, the ADCK4 and NUMBL genes are aligned head-to-tail in chromosome 19 supporting the hypothesis that intergenic cis-splicing of ADCK4 (Exon 15) with NUMBL (Exon 2) drives expression of ADCK4-NUMBL chimeric transcripts. Similar transcripts have been detected in a few cell lines but are not observed in the vast RNA sequencing data available via the TCGA, suggesting that these transcripts are expressed commonly only in H/L patient samples. Based on the limited literature15-18, we hypothesize that intergenic splicing of ADCK4 with NUMBL drives expression of ADCK4-NUMBL chimeric transcripts and that these transcripts express oncoproteins with unique biological properties. To test these hypotheses, we will 1) determine how expression of ADCK4-NUMBL chimeric proteins influence cell biology, 2) establish novel patient-derived cell lines from H/L never smokers and 3) explore the mechanisms leading to the expression of cis-spliced ADCK2-NUMBL transcripts. We anticipate that the results of these studies will provide insight into the mechanisms driving the elevated lung cancer mortality among H/Ls who do not smoke and identify novel therapeutic targets.