(A) VPA Induces Notch1 Signaling in SCLC Cells. Western blots of cell extracts from DMS53 cells treated with control (DMSO 0.1%) or VPA (1 to 10 mM) for 2 d showed increased expression of full-length Notch1 and the cleaved, active Notch intracellular domain (NICD). Levels of Hes-1, a downstream target of Notch1, were also elevated from baseline with VPA treatments. Equal protein loading was confirmed with antibodies against G3PDH. (B) After quantification with image analysis software, there were statistically significant differences between control and treatment groups with full-length Notch, NICD, and Hes-1 expression (p-value <0.001).