NO-Donating NSAIDs, PPAR𝛿, and Cancer: Does PPAR𝛿 Contribute to Colon Carcinogenesis?

Figure 2

Effect of NO-ASA on PPARδ and apoptosis in colon tissue of Min mice. Upper panel: the evolution of necrotic areas in intestinal tumors treated with p-NO-ASA; sections are stained by the TUNEL method. (I) Coalescence of TUNEL positive cells (arrow), representing the earliest stage; (II) abundant apoptotic cells at the margins of the developing area with contrast to their rarity in the surrounding area; (III) and (IV) the necrotic area is increasing in size, but TUNEL positive cells persist at its margins; TUNEL positive areas within the necrotic areas (arrows) suggest their cellular origin. Lower panel: the relationship of PPARδ and apoptosis in NO-ASA treated intestinal tumors. Successive sections of intestinal tumors were stained for PPAR𝛿 expression and apoptosis. The untreated tumor shows strong PPARδ expression (A) and rare apoptotic cells (B). After treatment with meta or para NO-ASA, tumors show decreased PPARδ expression (C) and (E) and increased apoptosis (D) and (F). Magnification is x400, adapted from Ouyang et al. [7].