LAUSR

Abstract Background Probiotics have gained exponential attention worldwide because they are used as a therapeutic tool for management, prevention and treatment of diseases like cancer. Here, antiproliferation, anti-angiogenesis and antitumor effects of Lactobacillus acidophilus (LA) and Bifidobacterium longum (BL) were examined on gastric (AGS) and bladder (J253) cancer cell lines. Methods Cancer cell viability was monitored with MTT assay. The chick embryo chorioallantoic membrane (CAM) assay was used to screen tumor growth and hemoglobin content of cancer cells alone and with different LA and BL concentrations. Protein expression of COX2 was analyzed with Western blot in cell lines treated with LA, BL, celecoxib at 60 and 100 µM (a nonsteroidal anti-inflammatory drug and COX2 inhibitor), or their combination. Results Both probiotics showed increased vacuolated gastric cancer (AGS) cells with significant morphological changes at high concentration (2.5 × 107 cfu/ml) of LA and BL bacteria compared to bladder cancer cells (J253). Similarly, AGS cells responded well to LA and BL and decreased cancer cell viability, tumor weight and hemoglobin content (p Conclusions This study is the first to document antiproliferation and anti-angiogenesis of LA and BL against gastric cancer by downregulating COX2 expression. LA and BL might be new, safe agents for targeting COX2 and suppressing growth of some cancers.