Histological changes induced by refametinib treatment. (a) Left panel: TUNEL staining demonstrating apoptosis in refametinib treated mice 4 h and 24 h post-therapy. Right panel: Western blots demonstrating increase in apoptosis markers caspase 3 and cleaved PARP upon refametinib treatment in murine PDAC. (b) H&E staining of gemcitabine treated tumor demonstrating no changes in histology while refametinib treated tumors show decrease in cellularity and increase in intercellular space. MOVAT staining and quantification of ground substance demonstrated a ground substance increment in stroma (blue-green color) in refametinib treated tumors. One point presents one tumor. p = 0,027; (c). Real-time PCR demonstrates no differences in expression of enzymes involved in synthesis of ground substance, Has1 and Has2, among refametinib and vehicle treated tumors. Data normalized to cyclophilin.