Methionine-dependence and combination chemotherapy on human gastric cancer cells in vitro

AIM: To elucidate whether human primary gastric cancer and gastric mucosa epithelial calls in vitro can grow normally in a rnethionine (Met) depleted environment, i.e.Met-dependence, and whether Met-depleting status can enhance the killing effect of chemotherapy on gastric cancer cells.lMETHODS: Fresh human gastric cancer and mucosal tissueswere managed to form monocellular suspensions, whichwere then cultured in the Met-free but homocysteine-containing ( MetHcy+ ) medium, with differentchemotherapeutic drugs. The proliferation of the cells wasexamined by cell counter, flow cytometry (FCM) andmicrocytotoxicity assay (MTT).RESULTS: The growth of human primary gastric cancer cellsin Met Hcy+ was suppressed, manifested by the decrease oftotal cell counts [1.46±0.42 ( x 109@L-1) in Met-Hcy+ vs .64±0.44 ( x l09@L-1) in Met+ Hcy, P＜0.01], the decline inthe percentage of G0G1 phase cells (0.69±0.24 in Met-Hey+vs 0.80±0.18 in Met+ Hcy, P＜0.01) and the increase of Scells(0.24±0.20inMet-Hcy+ vs 0.17 ± 0.16 in Met+ Hcy-, P＜ 0.01); however, gastric mucusal cells grew normally. IfMet-Hcy+ medium was used in combination withchemotherapeutic drugs, the number of surviving gastriccancer cells dropped significantly.CONCLUSION: Human primary gastric cancer cells in vitroare Met-dependent; however, gastric mucosal cells have notshown the same characteristica. Met- Hcy+ environment maystrengthen the killing effect of chemotherapy on humanprimary gastric cancer cells.

AIM: To elucidate whether human primary gastric cancer and gastric mucosa epithelial cells in vitro can grow normally in a methionine (Met) depleted environment, i.e. Met-dependence, and whether Met-depleting status can enhance the killing effect of chemotherapy on gastric cancer cells. METHODS: Fresh human gastric cancer and mucosal tissues were managed to form monocellular suspensions, which were then cultured in the Met-free but homocysteine-containing (Met(-)Hcy(+)) medium, with different chemotherapeutic drugs. The proliferation of the cells was examined by cell counter, flow cytometry (FCM) and microcytotoxicity assay (MTT). RESULTS: The growth of human primary gastric cancer cells in Met(-)Hcy(+) was suppressed, manifested by the decrease of total cell counts [1.46 +/- 0.42 (x 10(9).L(-1)) in Met(-)Hcy(+) vs 1.64 +/-0.44(x 10(9).L(-1)) in Met(+)Hcy(-), P<0.01], the decline in the percentage of G(0)G(1) phase cells (0.69 +/- 0.24 in Met(-)Hcy(+) vs 0.80 +/- 0.18 in Met(+)Hcy(-), P<0.01) and the increase of S cells (0.24 +/- 0.20 in Met(-)Hcy(+) vs 0.17 +/- 0.16 in Met(+)Hcy(-), P<0.01); however, gastric mucosal cells grew normally. If Met(-)Hcy(+) medium was used in combination with chemotherapeutic drugs, the number of surviving gastric cancer cells dropped significantly. CONCLUSION: Human primary gastric cancer cells in vitro are Met-dependent; however, gastric mucosal cells have not shown the same characteristics. Met(-)Hcy(+) environment may strengthen the killing effect of chemotherapy on human primary gastric cancer cells.