Abstract LB074: Chymostatin, a cathepsin L inhibitor, inhibits lung cancer cell proliferation and COVID-19 Mproin vitro

Lung cancer patients are more vulnerable to COVID-19 infection. Treatment of patients with lung cancer during the current COVID-19 pandemic is challenging and development of drugs for COVID-19 and lung cancer is urgently needed. Cathepsin L plays key role in lung cancer progression, invasion and more so, endocytosis of SARS-Cov-2 virus into the lung epithelial cells. Importantly, patients with KrasG12V mutation show agreessive disease and high-resistance to chemotherapy due to over-expression of Cathepsin L. Thus, Cathepsin L is a common target for lung cancer and COVID-19 infection. Chymostatin is a known cathepsin L inhibitor, here we screened it for dual inhibition of COVID-19 Mpro and lung cancer patients with COVID-19. In vitro COVID-19 Mpro fluorometric assay was performed to evaluate its inhibitory efficacy by chymostatin. Chymostatin showed dose-dependent inhibition of COVID-19 Mpro activity with IC50 of 15.81 µM (P Citation Format: Nagendra Sastry Yarla, Gopal Pathuri, Simon Terzyan, Yuting Zhang, Anil Singh, Marcus T. Scotti, Venkateshwar Madka, Chinthalapally V. Rao. Chymostatin, a cathepsin L inhibitor, inhibits lung cancer cell proliferation and COVID-19 Mproin vitro [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB074.