Hypoxia Inducible Factor-1α Inhibition in Von Hippel Lindau-mutant Malignant Pleural Mesothelioma Cells.

Molecular targeted agents have been successfully developed against solid tumors and their use is also being investigated for the treatment of malignant pleural mesothelioma (MPM). We have previously reported von Hippel Lindau (VHL) mutations detected by massive parallel sequencing technology in samples of patients with MPM. Here, we conducted an in vitro study to investigate the therapeutic approaches in VHL-mutant MPM.Three MPM cell lines with or without a VHL mutation were used and the effects of molecular-targeted agents on growth inhibition were evaluated. Based on the characteristics of the molecular targeted agents that exhibited growth inhibitory effect, the effects of knockdown by siRNA were also evaluated.NCI-H28 MPM cells harboring the VHL L89H mutation were sensitive to YC-1, known as an inhibitor of hypoxia inducible factor (HIF)-1α, and YC-1treatment induced massive apoptosis in a dose-and-time-dependent manner. Knockdown of HIF-1α by siRNA partially inhibited the growth of NCI-H28 cells, suggesting that an additional blockade may be required to completely inhibit growth signaling.The VHL mutation may predict tumor responses to YC-1, a HIF-1α inhibitor.