Fig. 4.

Zinc sulfate and NF-κB inhibitors cooperatively suppress ACE2 expression in H322M and Calu-3 cells. (A) H322M cells were treated with various concentrations of zinc sulfate (0, 100, 200 or 300 μM) for 48 h, followed by lysis for Western blot analysis of ACE2 and PARP; β-actin was used as a loading control. (B) H322M cells were treated with zinc sulfate (300 μM) for 24 h, and total RNA was collected for ACE2 measurement by real-time qRT-PCR. The data were normalized to GAPDH. Error bars represent the mean ± SD (n = 3). (*P < 0.05.) (C) H322M cells and (D) Calu-3 cells were treated with triclabendazole (50 μM), emetine (100 nM), zinc sulfate (150 μM) alone, or in combination with zinc sulfate (150 μM) and triclabendazole or emetine for 24 h. Treated cells were lysed for Western blot analysis of ACE2 and PARP; β-actin was used as a loading control. The bands for full-length PARP (f-PARP) and the cleaved fragment (c-PARP) are indicated.