Use of a new class of phosphoinositide-dependent kinase-1 (PDK-1) inhibitors of formula I for inducing apoptosis in unwanted rapidly proliferating cells, for treating, inhibiting, or delaying the onset of cancer, and for preventing restenosis in a subject that has undergone an angioplasty or stent: wherein X is selected from the group consisting of alkyl and haloalkyl; Ar is an aryl radical selected from the group consisting of phenyl, biphenyl, naphthyl, anthryl, phenanthryl, and fluorenyl; and wherein Ar is optionally substituted with one or more radicals selected from the group consisting of halo, C1-C4 alkyl, C1-C4 haloalkyl, azido, C1-C4 azidoalkyl, aryl, akylaryl, haloaryl, haloalkylaryl, and combinations thereof; and R is selected from the group consisting of nitrile, acetonitrile, ethylnitrile, propylnitrile, carboxamide, amidine, tetrazole, oxime, hydrazone, acetamidine, aminoacetamide, guanidine, and urea.