A conjugate of formula: V--(Y).sub.a--Z-T: (I), T-X--B--(Y).sub.a--Z-T': (II), V--(Y).sub.a Z--(Y').sub.a V': (III), T-X--B--(Y).sub.a--Z--(Y').sub.a--X'--B'-T': (IV), V--(Y).sub.a--Z--(Y').sub.a--X--B-T: (V), V--(Y).sub.a--Z--X--B--Z'--(Y').sub.a--(V').sub.b: (VI), or (W).sub.a--(Y).sub.b--[(Z).sub.c--(Y').sub.d--(X--B).sub.e--(Y'').sub.f--- (Z').sub.g].sub.h--(Y . . . ).sub.i--(W').sub.j: (VII), in which W and W' are independently a DNA intercalator or terminal subunit, V and V' are independently a DNA intercalator, X and X' are independently a DNA alkylator, B and B' are the same or different and each is a heteoaromatic residue that is attached to the Nterminus of an alkylator subunit (X or X'), Y, Y', Y'' and Y''' are independently a linker, T and T' are independently terminal subunits, Z and Z' are independently a polyamide group that binds to the minor groove of DNA, a, b, c, d, f, g, i, and j are independently 0 to 5, and e and h are independently 1 to 5, a composition comprising a conjugate of any of formulae (I)-(VII) and a carrier, and a method for treating cancer in a mammal comprising administering an effective amount of a conjugate of any of formulae (I)-(VII) or a composition comprising same.