Belinostat (PXD101)

Inhibition of LSD1 activity by HDAC inhibitors. a MDA-MB-231 and MDA-MB-468 cells were exposed to indicated HDAC inhibitors for 24 h.

LSD1 and HDAC inhibitors exhibit synergistic growth inhibition. Cells were simultaneously treated with pargyline or HDAC inhibitors for 48 h.

HDACIs That Simultaneously Inhibit HDACs 1 and 6 Showed Greater Antileukemic Activities than HDACIs that Don’t at Cmax Concentrations. THP-1 cells were treated with LBH-589, PXD101, SAHA, VPA, MS-275 and MGCD0103 at Cmax concentrations for 3 h and 24 h, respectively. The cells post 3 h treatments were washed three times with complete medium and divided into two halves. One half of the cells was resuspended in complete media and cultured for up to 24 h to determine the effects of the 3 h treatments on cell proliferation and apoptosis. The other half of the cells was used to prepare whole cell lysates. Whole cell lysates from the 3 h and 24 h treatments were extracted and subjected to Western blots probed by anti-ac-tubulin or –b-actin antibody (panels A&B), or subjected to HDAC1 enzymatic assays post IP as described in the Materials and Methods (Panels C&D). The effects of the 3 h and 24 h HDACI treatments on cell proliferation, as reflected by percent decrease of live cells relative to untreated cells (panel E), and apoptosis (panel F) were determined by flow cytometry analysis as described in the Materials and Methods.

Induction of DNA Damage and Bim Is Critical for HDACI-Induced Apoptosis in Pediatric AML Cells. THP-1 cells were treated with the HDACIs at Cmax concentrations for 3 (panel A) and 24 h (panel B), respectively. Whole cell lysates were extracted and subjected to Western blots probed by anti-p21, -c-Myc, -cH2AX, -Bim, or -b-actin antibody.

MDA-MB-231 Breast cancer cells were pretreated with Acetyl-H3 and H3, and then treated with the indicated concentrations of  PXD101.