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Updated: Jan 13, 2026
Intramucosal Inoculation of Squamous Cell Carcinoma Cells in Mice for Tumor Immune Profiling and Treatment Response Assessment
Published on: April 22, 2019
Vendor-specific microbiomes influence oral cancer development and its response to Streptococcus mitis intervention in
Doaa E El-Hadedy1, Tsute Chen2, Kathy Q Cai3
1Department of Oral Health Sciences, Oral Microbiome Research Laboratory, Maurice H. Kornberg School of Dentistry, Temple University, Philadelphia, PA, USA.
Background:
We previously demonstrated that Streptococcus mitis exhibits anticancer properties in vitro. Here, we sought to validate these findings in vivo. Because mice from different vendors harbor distinct microbiomes that can influence disease susceptibility and experimental outcomes, we also examined whether vendor-specific oral and gut microbiomes affect oral carcinogenesis and response to S. mitis intervention.
Materials And Methods:
Oral carcinogenesis was induced using 4-NQO in C57BL/6 mice from Jackson Laboratory and Taconic Biosciences (n = 32 per vendor). Mice were randomized to biweekly oral swabbing with S. mitis or vehicle for 28 weeks. Oral and fecal microbiomes were profiled at baseline and week 8. At week 32, tongues were evaluated for tumor development.
Results:
Oral and gut microbiomes differed significantly between vendors. 4-NQO exposure induced marked microbial shifts and partial convergence of microbiome profiles. Jackson mice developed a significantly higher squamous cell carcinoma (SCC) burden. Several microbial taxa were associated with SCC, notably Clostridium, which was enriched in oral and fecal samples from Jackson mice. S. mitis reduced SCC burden in both cohorts and was accompanied by decreased Clostridium abundance.
Conclusions:
These data support S. mitis as a potential anticancer agent and underscore the importance of microbiome context in preclinical cancer models.
Insights
Streptococcus mitis shows anticancer effects in vivo, reducing oral cancer burden in mice. Microbiome differences between mouse vendors impacted cancer development and response to S. mitis intervention.
Area of Science:
- Microbiology
- Oncology
- Immunology
Background:
- Previous in vitro studies showed Streptococcus mitis possesses anticancer properties.
- This study aimed to validate these anticancer findings in vivo.
- The influence of vendor-specific microbiomes on oral carcinogenesis and S. mitis efficacy was investigated.
Purpose of the Study:
- To validate the in vivo anticancer effects of Streptococcus mitis.
- To assess the impact of distinct mouse vendor microbiomes on oral carcinogenesis.
- To determine if microbiome context influences the response to S. mitis intervention.
Main Methods:
- Oral carcinogenesis was induced using 4-NQO in C57BL/6 mice from two different vendors.
- Mice received biweekly oral swabs of S. mitis or vehicle for 28 weeks.
- Oral and fecal microbiomes were analyzed, and tongue tumors were evaluated.
Main Results:
- Significant differences in oral and gut microbiomes were observed between mouse vendors.
- 4-NQO exposure altered microbial profiles; Jackson mice had higher squamous cell carcinoma (SCC) burden.
- S. mitis reduced SCC burden in both groups and was associated with decreased Clostridium abundance.
Conclusions:
- Streptococcus mitis demonstrates potential as an anticancer agent.
- Microbiome context is crucial for preclinical cancer models.
- Vendor-specific microbiomes influence experimental outcomes in oral carcinogenesis studies.
