Expression of SARS-CoV-2-Related Surface Proteins in Non-Small-Cell Lung Cancer Patients and the Influence of Standard of Care Therapy

SIMPLE SUMMARY: SARS-CoV-2 is a respiratory virus that uses ACE2 for host cell entry and the spike protein is primed by, among others, TMPRSS2 and FURIN. The goal of this study was to determine in which non-small-cell lung cancer (NSCLC) patients these proteins are expressed on the membrane of the lung cancer cells and in which patients this increased ACE2 expression results in higher levels of soluble (s)ACE2 in their serum. In addition, we studied the influence of standard of care (SOC) therapies on sACE2 levels. Membranous (m)ACE2 was co-expressed with mFURIN and/or mTMPRSS2 in 16% of the NSCLC patients, and mACE2 and sACE2 were more frequently expressed in mutant EGFR patients but not mutant-KRAS patients. Importantly, systemic SOC therapies did not result in increased sACE2 levels. This indicates that cancer cells can be infected by SARS-CoV-2 in these patients, as well as that soluble ACE2 could impact the course of COVID-19. ABSTRACT: In this study, we aimed to study the expression of SARS-CoV-2-related surface proteins in non-small-cell lung cancer (NSCLC) cells and identify clinicopathological characteristics that are related to increased membranous (m)ACE2 protein expression and soluble (s)ACE2 levels, with a particular focus on standard of care (SOC) therapies. ACE2 (n = 107), TMPRSS2, and FURIN (n = 38) protein expression was determined by immunohistochemical (IHC) analysis in NSCLC patients. sACE2 levels (n = 64) were determined in the serum of lung cancer patients collected before, during, or after treatment with SOC therapies. Finally, the TCGA lung adenocarcinoma (LUAD) database was consulted to study the expression of ACE2 in EGFR- and KRAS-mutant samples and ACE2 expression was correlated with EGFR/HER, RAS, BRAF, ROS1, ALK, and MET mRNA expression. Membranous (m)ACE2 was found to be co-expressed with mFURIN and/or mTMPRSS2 in 16% of the NSCLC samples and limited to the adenocarcinoma subtype. TMPRSS2 showed predominantly atypical cytoplasmic expression. mACE2 and sACE2 were more frequently expressed in mutant EGFR patients, but not mutant-KRAS patients. A significant difference was observed in sACE2 for patients treated with targeted therapies, but not for chemo- and immunotherapy. In the TCGA LUAD cohort, ACE2 expression was significantly higher in EGFR-mutant patients and significantly lower in KRAS-mutant patients. Finally, ACE2 expression was positively correlated with ERBB2-4 and ROS1 expression and inversely correlated with KRAS, NRAS, HRAS, and MET mRNA expression. We identified a role for EGFR pathway activation in the expression of mACE2 in NSCLC cells, associated with increased sACE2 levels in patients. Therefore, it is of great interest to study SARS-CoV-2-infected EGFR-mutated NSCLC patients in greater depth in order to obtain a better understanding of how mACE2, sACE2, and SOC TKIs can affect the course of COVID-19.