Parvimonas micra infection enhances proliferation, wound healing, and inflammation of a colorectal cancer cell line

Abstract

Abstract The gut microbiota Parvimonas micra has been found to be enriched in gut mucosal tissues and fecal samples of colorectal cancer (CRC) patients compared with non-CRC controls. In the present study, we investigated the tumorigenic potential of P. micra and its regulatory pathways in CRC using HT-29, a low-grade CRC intestinal epithelial cell. For every P. micra-HT-29 interaction assay, HT-29 was co-cultured anaerobically with P. micra at an MOI of 100:1 (bacteria: cells) for 2 h. We found that P. micra increased HT-29 cell proliferation by 38.45% (P=0.008), with the highest wound healing rate at 24 h post-infection (P=0.02). In addition, inflammatory marker expression (IL-5, IL-8, CCL20, and CSF2) was also significantly induced. Shotgun proteomics profiling analysis revealed that P. micra affects the protein expression of HT-29 (157 up-regulated and 214 down-regulated proteins). Up-regulation of PSMB4 protein and its neighbouring subunits revealed association of the ubiquitin–proteasome pathway (UPP) in CRC carcinogenesis; whereas down-regulation of CUL1, YWHAH, and MCM3 signified cell cycle dysregulation. Moreover, 22 clinically relevant epithelial–mesenchymal transition (EMT)-markers were expressed in HT-29 infected with P. micra. Overall, the present study elucidated exacerbated oncogenic properties of P. micra in HT-29 via aberrant cell proliferation, enhanced wound healing, inflammation, up-regulation of UPPs, and activation of EMT pathways.