Determining the role of SARS-CoV-2 in driving premalignancy of the airway

Project Summary/AbstractLung cancer is thought to develop in a stepwise fashion giving us the opportunity to intervene before it becomesinvasive. A novel approach to cure patients of lung cancer is therefore to develop a targeted chemopreventionstrategy to prevent the formation of lung premalignant lesions in the first place. My lab studies airway epithelialstem cells (AESCs) and the signaling pathways involved in their repair and regeneration after injury. Our studiesled us to the conclusion that premalignancy represents a state of excessive self-renewal of AESCs with a blockin differentiation and we identified several mechanisms involved in stepwise progression to lung cancer. Onesuch mechanism involves proliferation of AESCs via the Wnt-β-catenin pathway and in particular we found thatonly one of the differential phosphorylation sites, the tyrosine Y489 residue of the β-catenin protein, allowednuclear localization of β-catenin with concomitant TCF/LEF activation for proliferation. This phosphorylation ofβ-catenin at Y489 is not present in normal airway AESCs but persists in premalignant lesions and lung cancer. We have developed human and mouse in vitro models of premalignancy in the proximal and distal airwayepithelium by driving Wnt/β-catenin signaling. These models include the air-liquid interface model of proximalairway stem cell proliferation and differentiation (Aros et al, 2020) and a 3D lung organoid co-culture model withtype I and type II alveolar epithelial cells. We are currently infecting our lung premalignancy models withSARS-CoV-2, in collaboration with Dr. Arumugaswami at UCLA to assess how viral infection alters this aberrantresponse to injury. Our hypothesis is that SARS-CoV-2 infection in the setting of premalignancy with excessive proliferationof AESCs will result in persistent Wnt/β-catenin signaling which will prevent the resolution of premalignant lesionsand allow additional mutations to develop to drive invasive carcinoma. Our goal is to understand the effects ofSARS-CoV-2 on Wnt/β-catenin signaling and especially p-β-cateninY489 in premalignant lesions using thefollowing approaches:Specific Aim: To understand the role of SARS-CoV-2 on p-β-cateninY489 in proliferation of AESCs inpremalignant lesions. We hypothesize that p-β-cateninY489 is induced by SARS-CoV-2 for repair after infectionand prevents resolution of existing premalignant lesions.Specific Aim 1a: We will identify how frequently SARS-CoV-2 infection drives Wnt/β-catenin signaling and leadsto the p-β-cateninY489 in AESCs in proximal and distal airway models.Specific Aim 1b: We have identified a compound that prevents p-β-cateninY489 in AESCs (Aros et al, 2020) andwill test the effects of this compound on SARS-CoV-2 infected proximal and distal airway premalignancy models.Specific Aim 1c: We will use transgenic mouse models with loss of β-catenin in the AESCs of the proximal airwayand examine the effects on repair of the airway after SARS-CoV-2 infection.