Abstract 2213: Generating a collection of isogenic lung adenocarcinoma cell lines to study RAS gene activation in black Americans
Authors: Puente Pablo E. , Yan Chunli , Gregory Matthew , Belony Nadine L. , Lamango Nazarius , Huang Yong , Offringa Ite A. 
Published: June 2022

Abstract
Lung cancer is a source of cancer health disparity among black Americans, especially men. Lung cancer incidence rates and mortality rates are higher in black Americans than in white Americans despite lower tobacco exposure among black men than white men. Lung adenocarcinoma (LUAD) is the most common subtype of lung cancer in all ethnic/racial groups, including blacks. Genetic driver mutations differ among racial/ethnic groups. In addition, the same mutation could have different effects based on the genetic background arising from different racial/ethnic groups. Therefore, it is important to study appropriate driver mutations in the correct genetic background. Protooncogenes from the RAS family, KRAS, NRAS, and HRAS, play a crucial role in cell growth regulation, cell proliferation, and survival. KRAS is the most frequently mutated driver gene in black LUAD (~14%). NRAS mutations are also seen (1-2%). It is therefore important to study LUAD cell lines carrying different RAS mutations in black Americans’ genetic backgrounds. Unfortunately, to our knowledge, there is only one LUAD cell line from a black subject. The NCI-H23 cell line contains a heterozygous KRAS mutation at codon 12. We are generating a collection of isogenic cell lines derived from NCI-H23, tailored to study RAS gene activation in black Americans. We will correct the KRAS mutation to wildtype through CRISPR/Cas9 deletion with co-transfection of the wild-type sequence. However, we expect that the NCI-H23 cells may not tolerate the removal of the KRAS without simultaneous replacement with another driver mutation. Therefore, we will replace the KRAS mutation with either mutated NRAS, HRAS, or EGFR. EGFR functions as a receptor tyrosine kinase in the RAS-RAF-MEK-ERK pathway to control the activation of RAS oncogenes and is also frequently mutated in black LUAD (~8%). We have identified a heterozygous single nucleotide polymorphism, rs11047919, 839 nucleotides downstream from the KRAS mutation which we are using to differentiate between the wild-type and mutated KRAS alleles following CRISPR editing. We will use the new cell lines to test the efficacy of polyisoprenylated cysteinyl amide inhibitors (PCAIs). These agents have been shown to disrupt RAS-mediated signaling in ethnically/racially diverse cell lines. In the future, we will develop immortalized alveolar epithelial cell lines from black subjects to further address the lack of lung cancer models representing black Americans. Through our research, we intend to address one facet of the prominent lack of representation of black Americans in LUAD studies.
Citation Format: Pablo E. Puente, Chunli Yan, Matthew Gregory, Nadine L. Belony, Nazarius Lamango, Yong Huang, Ite A. Offringa. Generating a collection of isogenic lung adenocarcinoma cell lines to study RAS gene activation in black Americans [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2213.