A series of novel 4-(4-substituted-thiazol-2-ylamino)-N-(pyridin-2-yl) benzene-sulfonamides were synthesized and screened for their cytotoxic activity against human breast cancer cell line (MCF-7). Compounds 6, 7, 9, 10, 11, and 14 displayed significant activity against MCF-7 when compared to doxorubicin, which was used as a reference drug. The synergistic effect of Gamma radiation for the most active derivatives 7, 9, and 11 was also studied and their $IC_{50}$ values markedly decreased to $11.9{mu}M$, $11.7{mu}M$, and $11.6{mu}M$, respectively.