Figure 2.

Electron microscopic observation of cell-surface and cell-morphology in CRC cells after treatment with TNF-β or/and resveratrol. HCT116, RKO, and SW480 were cultured in a monolayer culture and were untreated (a–c), or treated with TNF-β (d–f) or TNF-α with resveratrol (g–i) alone, or with TNF-β and co-treated with resveratrol (j–l), or TNF-α and co-treated with resveratrol, as described above and investigated with a transmission electron microscope. (A) Untreated control (Co) tumor cells showed a planar surface and moderate microvilli (arrows) on the cell surface (a–c). By contrast, treatment with TNF-β or TNF-α resulted in alteration of cell surface ultrastructure and cells contained abundant, long microvilli and filopodia-like structures on the cell surface (d–f). By contrast, treatment of tumor cells with resveratrol alone (g–i) or co-treated cells with resveratrol and TNF-β (j-l) displayed only a few microvilli, with an overall planar surface. Tumor cells became rounded and the nucleus contained more heterochromatin, multiple vacuoles, and swelling of cell organelles like mitochondria. Apoptotic bodies (arrowheads) and cell lysis (*) was visible. a–l: Magnification, 5000x. Scale bar = 1 μm. Insets: Scale bar = 0.09 µm. To quantify mitochondrial changes (MC) and apoptosis in tumor cells, 100 cells from 25 microscopic fields were counted. Values were compared with the control and statistically significant values with p < 0.05 were designated by (*) and p < 0.01 were designated by (**). (B) Effect of resveratrol on E-cadherin expression in CRC cells shown by immunoelectron microscopy. Immunogold labeling (arrows) is observed at the plasma membrane of CRC cells with antibodies against E-cadherin. Scale bars = 0.2 µm.