In vitro activity of probiotic Lactobacillus reuteri against gastric cancer progression by downregulation of urokinase plasminogen activator/urokinase plasminogen activator receptor gene expression

Background: Gastric cancer (GC) is the third leading cause of cancer death, and most patients represent metastatic phenotype at the time of diagnosis. Urokinase plasminogen activator (uPA) system is well known for its critical roles in cancer cells invasion since uPA/uPA receptor (uPAR) overexpresses in several cancers. Subsequently, suppression of uPA/uPAR gene expression improves patients overall survival and prevents cancer progression. Objectives: The aim of the current study was to investigate possible effects of live Lactobacillus reuteri as a probiotic in inhibition of GC cells proliferation and invasion. Materials and Methods: Human gastric adenocarcinoma epithelial cell line (AGS) cells were treated with different ratios of live L. reuteri and were incubated for 24, 48, and 72 h. Viability of cancer cells was measured with 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide assay, and the effects of L. reuteri on uPA/uPAR gene expression were assessed by real-time polymerase chain reaction. Results: Our results showed that L. reuteri inhibits cell proliferation significantly in dose-dependent manner. Expressions of uPA and uPAR were downregulated followed by co-incubation of AGS cells and live L. reuteri compared to untreated-based line level. Conclusion: This study provides strong support in the role of L. reuteri in suppression of GC cell invasion by downregulation of pathways which is involved in extracellular matrix degradation such as uPA and uPAR.