New quinoline derivatives 6, 7 and 19, pyrimidoquinoline derivatives 8-16 and triazolopyrimidoquinoline derivatives 17 and 18 bearing a bromo-substituent were synthesized starting from 3-(4-Bromophenylamino)-5,5-dimethylcyclohex-2-enone 3. All the newly synthesized compounds were evaluated for their in vitro anticancer activity against human breast cancer cell line (MCF7). Compounds 9, 11, 17 and 18 showed $IC_{50}$ values (36.4, 39.7, 39.02 and 36.4 ${mu}M$, respectively) comparable to that of the reference drug doxorubicin ($IC_{50}=32.02{mu}M$). On the other hand, compound 6, 14 and 19 exhibited better activity than doxorubicin with $IC_{50}$ values of 8.5, 23.5 and 23.7 ${mu}M$. Additionally, the most potent compounds 6, 14 and 19 were evaluated for their ability to enhance the cell killing effect of ${gamma}$-radiation.