Porphyromonas gingivalis Promotes Oral Squamous Cell Carcinoma Progression by Modulating Autophagy.

OBJECTIVES: Porphyromonas gingivalis (P. gingivalis) is a keystone periodontal pathogen associated with various gastro-intestinal tract cancers. However, whether P. gingivalis can promote oral squamous cell carcinoma (OSCC) and the underlying mechanism associated with such promotion remain unclear. MATERIALS AND METHODS: In this study, OSCC xenograft models were used to evaluate the effects of P. gingivalis on tumor progression. The functional studies were done on several OSCC cell lines in vitro. P. gingivalis-specific 16S rRNA fluorescent in situ hybridization (FISH) was used to test its prevalence in clinical samples. RESULTS: We found that P. gingivalis increased tumor volume and tumor growth in OSCC nude models. Functional studies demonstrated that P. gingivalis inhibited the apoptosis of OSCC cells by promoting cellular autophagy. P. gingivalis was more prevalent in FISH samples from patients with OSCC than from patients with leukoplakia or healthy subjects (70% vs. 47.2% vs. 33.3%, p = 0.045 and p < 0.001, respectively). CONCLUSION: These data suggest that P. gingivalis plays an accelerating role in OSCC progression and contributes to OSCC by enhancing the autophagy pathway to reduce carcinoma apoptosis.