Postbiotics of Lacticaseibacillus paracasei CECT 9610 and Lactiplantibacillus plantarum CECT 9608 attenuates store-operated calcium entry and FAK phosphorylation in colorectal cancer cells.

Store-operated Ca entry (SOCE) is a major mechanism for Ca influx in colorectal cancer (CRC) cells. This mechanism, regulated by the filling state of the intracellular Ca stores, is mediated by the endoplasmic reticulum Ca sensors of the stromal interaction molecules (STIM) family [stromal interaction molecule 1 (STIM1) and STIM2] and the Ca-release-activated Ca channels constituted by Orai family members, with predominance of calcium release-activated calcium channel protein 1 (Orai1). CRC cells exhibit enhanced SOCE due to remodeling of the expression of the key SOCE molecular components. The enhanced SOCE supports a variety of cancer hallmarks. Here, we show that treatment of the colorectal adenocarcinoma cell lines HT-29 and Caco-2 with inanimate Lacticaseibacillus paracasei (CECT9610) and Lactiplantibacillus plantarum (CECT9608) attenuates SOCE, although no detectable effect is seen on SOCE in normal colon mucosa cells. The effect of Lacticaseibacillus paracasei and Lactiplantibacillus plantarum postbiotics was mediated by downregulation of Orai1 and STIM1, while the expression levels of Orai3 and STIM2 remained unaltered. Treatment of HT-29 and Caco-2 cells with inanimate Lacticaseibacillus paracasei and Lactiplantibacillus plantarum impairs in vitro migration by a mechanism likely involving attenuation of focal adhesion kinase (FAK) tyrosine phosphorylation. Cell treatment with the Orai1 inhibitor synta-66 attenuates SOCE and prevents any further effect of Lacticaseibacillus paracasei and Lactiplantibacillus plantarum postbiotics. Together, our results indicate for the first time that Lacticaseibacillus paracasei and Lactiplantibacillus plantarum postbiotics selectively exert negative effects on Ca influx through SOCE in colorectal adenocarcinoma cell lines, providing evidence for an attractive strategy against CRC.