ACE2 and lung adenocarcinoma: We examined whether SARS-CoV-2 similarly blocks nuclear export of host mRNA by infecting the human lung adenocarcinoma cell line, Calu3, and a human bronchial epithelial cell line stably expressing the SARS-CoV-2 receptor angiotensin-converting enzyme 2 (ACE2), HBEC3-ACE2, with SARS-CoV-2.