Design, synthesis and biological evaluation of 2H-benzo[b][1,4] oxazine derivatives as hypoxia targeted compounds for cancer therapeutics.

A small library of 2H-benzo[b][1,4] oxazine derivative was synthesized and their biological activity was tested on HepG2 cells under normoxic and hypoxic conditions. From preliminary screening, we found compound 10 and 11 specifically inhibit hypoxic cancer cell growth IC(50) 87+/-1.8microM and IC(50) 10+/-3.7microM while sparing 'normoxic' cells IC(50) >600M and >1mM (not applicable), respectively. We tested the effect of 10 on MTT, clonogenic and hypoxia induced genes. The MTT correlates with clonogenic assays and most importantly compound 10 down regulates hypoxia induces genes (HIF-1alpha, P21 and VEGF) appropriately. We are in the process to explore the molecular mechanism of action of oxazine derivative compounds on hypoxia tumor cells.