Quinazoline Sulfonamides as Dual Binders of the Proteins B-Cell Lymphoma 2 and B-Cell Lymphoma Extra Long with Potent Proapoptotic Cell-Based Activity

ABT-737 and ABT-263 are potent inhibitors of the BH3 antiapoptotic proteins, Bcl-xL and Bcl-2. This class of putative anticancer agents invariantly contains an acylsulfonamide core. We have designed and synthesized a series of novel quinazoline-based inhibitors of Bcl-2 and Bcl-xL that contain a heterocyclic alternative to the acylsulfonamide. These compounds exhibit submicromolar, mechanism-based activity in human small-cell lung carcinoma cell lines in the presence of 10% human serum. This comprises the first successful demonstration of a quinazoline sulfonamide core serving as an effective benzoylsulfonamide bioisostere. Additionally, these novel quinazolines comprise only the second known class of Bcl-2 family protein inhibitors to induce mechanism-based cell death.