Apoptosis Induction on AGS Gastric Adenocarcinoma and HEF Fibroblast Cell Lines by Wild Type and cagA or vacA Negative Helicobacter pylori Strains

Helicobacter pylori is one of the most common pathogens affecting humans and is the major environmental factor in the development of gastric cancer increasing from 4 to 6 folds the risk of its development. Variations in cancer risk among H. pylori infected individuals may correlate to difference in H. pylori strains, variable host characteristics and specific interactions between host and microbial determinants. To determine the effect of different strains of H. pylori on cellular apoptosis we designed an in vitro model using AGS and HEF cell lines. After specified time intervals total cell proteins was extracted and subjected to SDS-PAGE and immunoblotting using anti poly ADP-ribose polymerase (PARP) antibody. Decrease in densitometric value of PARP was indicative of higher level of apoptosis. The ability of apoptosis induction in AGS and HEF cell lines by wild type, cagA negative and vacA negative strains were significantly different. The assessed apoptosis in AGS cell line co-cultured with wild type strain was 3.22±0.2 in 24 h, 2.8±0.1 in 48 h, and 2.1±0.09 in 72 h of incubation time. Similar assessment with cagA negative strains in AGS cells was 4.17±1.49 in 24 h., 3.32±0.45 in 48 h., and 2.32±0.61 in 72 h. incubation. A variation in apoptotic potential between the H. pylori strains on two cells (AGS and HEF) was observed. Based on our results, it is concluded that H. pylori strains as well as target cell types are important in pathogenesis and induction of apoptosis during a specified time interval.