Notes: HAMNO is a small molecule inhibitor of replication protein A (RPA).{45417} It selectively binds to and inhibits DNA binding domain F (DBD-F) on RPA70 when used at concentrations up to 100 µM. HAMNO inhibits etoposide-induced autophosphorylation of ATR kinase and subsequent phosphorylation of RPA32 in UMSCC38 cells when used at concentrations of 10 and 20 µM. HAMNO (1 mg/kg), in combination with etoposide (Item No. 12092), reduces tumor growth in UMSCC11B and UMSCC38 mouse xenograft models.