Maillard reaction product-rich food impair cell proliferation and induce cell death in vitro

Maillard reaction products (MRPs) and advanced glycation end-products (AGEs) correspond to modified protein derivatives that are initially generated by non-enzymatic glycation between amino acids and reducing sugars in heat-treated foods and in vivo, respectively. Because lung tissue highly expresses the receptor for advanced glycation end-products (RAGE), we studied the impact of MRP/AGE-rich foods like bread crust (BC) and coffee extract (CE) on the proliferation and cell death induction using lung epithelial (H358) cells. Here, we showed that CE impairs the proliferation and viability of H358 cells at much higher extent than BC does. Particularly cell death induced by CE showed a concentration-dependent shift from apoptotic to necrotic features as estimated by caspase activation, phosphatidylserine exposure, leakage of the outer membrane, mitochondrial dysfunction and stress kinase activation. Moreover, CE at higher dose triggered the generation of reactive oxygen species thereby mediating caspase inhibition. Non-toxic concentrations of both foods only impaired the proliferation associated with an increased amount of cells in the S/G2 phase of the cell cycle, which did not depend on the over-expression of RAGE. From our data we conclude that MRP/AGE-rich foods mediate antiproliferative effects at moderate concentrations that might be important in physiological conditions like cancer prevention but contribute to cell death at higher levels in vitro.