Figure 7. Cell viability of MCF-7 and U2OS cells with different DOX and 5-HTP treatments. (A) DOX-induced antineoplastic activities of 5-HTP in MCF-7 cells. (B) DOX-induced antineoplastic effects of 5-HTP in U2OS cells. *P < 0.05 vs. the Control group, #P < 0.05 vs. the DOX group.