Targeting the BCL2 Gene Promoter G-Quadruplex with a New Class of Furopyridazinone-Based Molecules.

Targeting of G-quadruplex-forming DNA in the BCL2 gene promoter to inhibit the expression of anti-apoptotic Bcl-2 protein is an attractive approach to cancer treatment. So far, efforts made in the discovery of molecules that are able to target the BCL2 G-quadruplex have succeeded mainly in the identification of ligands with poor drug-like properties. Here, a small series of furo[2,3-d]pyridazin-4(5H)-one derivatives were evaluated as a new class of drug-like G-quadruplex-targeting compounds. Biophysical studies showed that two derivatives could effectively bind to BCL2 G-quadruplex with good selectivity. Moreover, one such ligand was found to appreciably inhibit BCL2 gene transcription, with a substantial decrease in protein expression levels, and also showed significant cytotoxicity toward the Jurkat human T-lymphoblastoid cell line.