Novel pyrazolo[3,4-d]pyrimidine derivatives inhibit human cancer cell proliferation and induce apoptosis by ROS generation.

The paucity of effective anticancer drugs for successful treatment is a major concern, indicating the strong need for novel therapeutic compounds. In the quest of new molecules, the present study aimed to explore the potential of pyrazolo[3,4-d]pyrimidine derivatives as antiproliferative agents. In vitro anticancer screening of selected compounds was done by the National Cancer Institute's Developmental Therapeutics Programme against a panel of 60 cancer cell lines. The lead compound PP-31d considerably inhibited the growth of cancer cells, such as NCI-H460 (non-small-cell lung cancer), OVCAR-4 (ovarian cancer), 786-0 (renal cancer), A549 (non-small-cell lung cancer), and ACHN (renal cancer), showing strong anticancer potential, among other derivatives. Kinetic studies of PP-31d on NCI-H460 cells revealed a dose-dependent effect with an IC of 2 µM. The observed inhibition by PP-31d is attributed to the generation of reactive oxygen species and the subsequent induction of cellular apoptosis, as evidenced by the increase in the hypodiploid (subG1) population, the early apoptotic cell population, and caspase-3/7 activity, the loss of the mitochondrial membrane potential, and the degradation of nuclear DNA. Collectively, our results demonstrated that pyrazolo[3,4-d]pyrimidine derivatives inhibit cancer cell proliferation by inducing apoptosis and, thus, have the potential to be further explored for anticancer properties.