Intratumoural microorganism can affect the progression of hepatocellular carcinoma.

Background: Several recent studies have confirmed that intratumoural microorganisms can affect the occurrence and development of hepatocellular carcinoma (HCC); however, their role in tumor progression remains unclear. Hence, there is a need for further research on the role of intratumoural microorganisms in HCC.

Aim: To investigate the changes in intratumoural microorganisms in HCC and the effect of Propionibacterium on HCC progression.

Methods: HCC and normal liver tissue specimens were subjected to fluorescence in situ hybridization (FISH). After performing 16S rRNA sequencing on HCC and peritumoral tissues to analyze the differences between the two groups. Propionibacterium was cocultured with HCC cells in vitro. Changes in cell proliferation and migration capacity were evaluated. The expression of NF-κB pathway related proteins in tumor cells was compared. The orthotopic liver implantation model and the subcutaneous xenograft model were constructed. liver tissues and subcutaneous tumors were collected 2 weeks later.

Results: FISH demonstrated the presence of microorganisms in HCC and normal liver tissues. 16S rRNA sequencing revealed an abundance of Lysobacter, Lachnospiraceae, Pseudomonas, and Lactobacillus in HCC tissues. The distribution and abundance of Propionibacterium showed differences between HCC and peritumoral tissues (P < 0.05). In vitro studies demonstrated that Propionibacterium and its metabolite propionic acid (PA) inhibited the proliferation and migration of HCC cells (P < 0.05). The expression of the proteins in NF-κB signaling pathway also decreased in HCC cells (P < 0.05).

Conclusion: Microorganisms in HCC and normal liver tissues displayed significant disparities. The PA-producing bacterium Propionibacterium in HCC exerts an effect on the NF-κB pathway, thereby affecting the biological behavior of HCC.