Fig. 1.

The pan-HDAC inhibitor AR42 enhances M1 macrophage infiltration into the tumor 5 weeks after drug exposure. Trametinib/dabrafenib-resistant MEL28 melanoma cells were implanted into the rear flanks of athymic mice. Tumors were treated with vehicle control or with AR42 (15mg/kg) for 2 days. Thirty-five days later, at the time of animal nadir, tumors were fixed, embedded in paraffin, and 4-μm sections obtained. Sections were deparaffinized, renatured, and stained to examine (10 × mag.) the colocalization of F4/80 staining and iNOS staining (that stains for M1 macrophages).