Figure 2. Differential in vitro effects of MSA and SN38 in hypoxic cells expressing HIF-1α and in normoxic cells with no detectable HIF1α protein expression.

(A). Effects of MSA on the level of apoptosis induced by MSA and SN38 in hypoxic FaDu tumor cells expressing HIF1α, and, in HIF-1α shRNA knockdown FaDu cells treated with SN38 alone (B). Effects of MSC on the antitumor activity of anticancer drugs in head and neck FaDu and A253; colorectal HCT8 and HT29 xenografts, and, in rats bearing Ward colon tumors (C). Effects of MSC on the toxicity induced by lethal doses of anticancer drugs (D). CR, complete tumor response with no evidence of tumor relapse at 3 months.