Discovery of anti-tumor small molecule lead compounds targeting the SH3 domain of c-Src protein through virtual screening and biological evaluation.

c-Src, also known as cellular Src, is a non-receptor tyrosine kinase that plays a crucial role in various cellular processes, including cell proliferation, adhesion, and migration. Its dysregulation has been implicated in the development and progression of several diseases, particularly cancer. Current therapeutic agents targeting c-Src are primarily small molecules binding to its kinase domain. However, drug resistance often reduces the effectiveness of these drugs. The SH3 domain of c-Src is a highly conserved functional region with a low propensity for developing drug resistance, whereas there are no existing anti-cancer drugs specifically binding to this domain. In this study, structure-based virtual screening and thermal shift experimental verification identified three molecules that showed potent binding affinity with SH3 domain of c-Src. Subsequent kinase activity assay validated the inhibitory activity of these compounds against c-Src, with IC values ranging from 60.42 to 122.2 nM. Next, cell-level assays and preliminary study were conducted to further evaluate the efficacy of the identified active compounds. In conclusion, the present work has provided new chemical templates as lead structures for the future development of new antitumor therapeutics targeting the c-Src SH3 domain to overcome drug resistance.