Porphyromonas gingivalis enhances the proliferation of colorectal cancer Caco-2 cells via the JAK2-STAT3 pathway

Abstract

Objective To investigate the effect of pathogenic bacterium-Porphyromonas gingivalis (P.g) on the proliferation and inflammatory factor expression of human colorectal cancer Caco-2 cells, to determine whether the Janus kinase 2-signal transducers and activators of transcription 3 (JAK2-STAT3) pathway is involved in the regulation of Caco-2 cell proliferation by P.g and to provide an experimental basis for further exploring the relationship between P.g and colorectal cancer. Methods Caco-2 cells were cultured in vitro, and P.g at different multiplicities of infection (MOIs) (0, 1, 10, 25) was selected to stimulate for 12, 24 and 48 h. The effect of P.g on the proliferation of Caco-2 cells was detected by CCK8. The stimulation time was set as 12, 24 and 48 h. MOI=0 was the control group, and MOI=1, 10 and 25 comprised the experimental group. qRT-PCR and Western blot were used to detect the changes in interleukin-6 (IL-6), interleukin-10(IL-10), JAK2 and STAT3 gene and protein (phosphorylated protein) levels in each group. Results After P.g infection of Caco-2 cells, P.g had a sustained stimulatory effect on the cells for 12, 24 and 48 h at MOI=1 and MOI=10 compared with the control group. Compared with that in the control group, the expression of pro-inflammatory factor IL-6 and related proliferative pathway protein JAK2 and STAT3 in Caco-2 cells with P.g infection increased in a concentration- and time-dependent manner (P<0.05). Additionally, the expression of IL-10, an anti-inflammatory factor, in Caco-2 cells infected with P.g decreased (P<0.05). After the addition of the JAK2 inhibitor AZ960, the proliferation of Caco-2 cells infected with P.g decreased, and the mRNA expression of STAT3 and JAK2 and the protein expression of p-STAT3 and p-JAK2 decreased (P<0.05). Conclusion P.g can promote the proliferation of the colorectal cancer cell line Caco-2, and the effect of P.g on Caco-2 cells may promote cell proliferation through the JAK2-STAT3 pathway while promoting the expression of the proinflammatory factor IL-6 and inhibiting the expression of the anti-inflammatory factor IL-10, creating an inflammatory environment conducive to cell proliferation, which may be the mechanism by which P.g affects the proliferation of Caco-2 cells.

Keywords

• periodontitis ，
• porphyromonas gingivalis ，
• colorectal cancer cells ，
• interluekin-6 ，
• interluekin-10 ，
• janus kinase 2 ，
• signal transducers and activators of transcription 3，