We next examined changes in cellular ultrastructure in response to treatment of pancreatic cancer cells with PA-MSHA by transmission electron microscopy. Treatment of PANC-1 and SW1990 cells with 0.5 × 109/mL PA did not alter the cellular morphology. However, treatment with 0.5 × 109/mL PA-MSHA for 24 hours resulted in cytoplasmic condensation, shrinkage of the cell body, nuclear fragmentation, mitochondrial enlargement, and the detachment and fusion of the endoplasmic reticulum with the plasma membrane to form multiple vacuoles. The presence of budding apoptotic bodies was indicative of the initiation of cellular breakdown in response to PA-MSHA treatment. Vacuole size and number increased after 48 hours of PA-MSHA treatment. At this time-point, most of the cells had died and the cytoplasmic structures had collapsed (Figure 2 and Figure 3).