Western blot analysis of the expression of proteins involved in the regulation of cell cycle and survival in MKN45 cells. After 48 hours of treatment with single agent or combined bromelain (100 and 200 μg/mL) and NAC (5 and 10 mM), activation of caspase system (represented by caspase proteins, cytochrome c and PARP), inhibition of anti-apoptotic and pro-survival processes (represented by Bcl-2 and phospho-Akt), diminution of the cell cycle regulators cyclin A, cyclin B and cyclin D along with the emergence of the autophagosomal marker LC3-II and deregulation of other autophagy-related proteins, including Atg3, Atg5, Atg7, Atg12 and Beclin 1, were found. As seen, results were more prominent in combination therapy. Our data implies that growth arrest, apoptosis and autophagy are likely mechanisms underlying cytotoxic effects of bromelain and NAC on gastrointestinal cancer cells. GAPDH was used as the loading control.