Figure 3

Abexinostat affects proplatelet formation. CD41⁺-sorted cells were seeded in triplicate in 96 wells with TPO and increasing doses of abexinostat (from 10 to 100 nM). Proplatelets were scored at day 12 under an inverted microscope. (a) Examples of proplatelet bearing MKs after treatment with indicated doses of the pan-HDACi. Proplatelet bearing MKs in control (i) and at 10 nM (ii) were similar; at 20 nM (iii), MK displayed less branching extensions compared with control MKs (i); at 50 nM (iv) and 100 nM (v) of abexinostat most MKs displayed apoptotic morphology and had shorter proplatelets. (b) Typical dose response of abexinostat on proplatelet formation. One representative experiment out of four experiments with increasing dose of abexinostat; ***P<0.0005. (c and d) Effects of a abexinostat short-time exposure on proplatelet formation. MKs were treated 24 h with 100 nM of abexinostat at day 8 (A-100 nM), then washed and seeded in triplicate in serum-free medium plus 10 ng/ml TPO. (d) Proplatelet formation was scored after 3 supplementary days of culture, n=2, P<0.0001. In c, even a short treatment (24 h) induces a proplatelet defect with a few extensions