Expansion of Candidate HPV-Specific T Cells in the Tumor Microenvironment during Chemoradiotherapy Is Prognostic in HPV16+ Cancers

Human papillomavirus (HPV) infection causes 600,000 new cancers worldwide each year. HPV-related cancers express the oncogenic proteins E6 and E7, which could serve as tumor-specific antigens. It is not known whether immunity to E6 and E7 evolves during chemoradiotherapy or affects survival. Using T cells from 2 HPV16⁺ patients, we conducted functional T-cell assays to identify candidate HPV-specific T cells and common T-cell receptor motifs, which we then analyzed across 86 patients with HPV-related cancers. The HPV-specific clones and E7-related T-cell receptor motifs expanded in the tumor microenvironment over the course of treatment, whereas non-HPV-specific T cells did not. In HPV16⁺ patients, improved recurrence-free survival was associated with HPV-responsive T-cell expansion during chemoradiotherapy.

Effect of Antibiotics on Gut and Vaginal Microbiomes Associated with Cervical Cancer Development in Mice

Antibiotics affect microbial diversity in the gut, leading to dysbiosis and impaired immunity. However, the impact of antibiotics on microbial communities at other sites, such as vagina is less understood. It is also not clear whether changes induced by antibiotics in both microbiomes affect the development of cervical cancer. In this study, we utilized the murine model to evaluate these questions. We show that oral application of broad-spectrum antibiotics in mice changed not only diversity, but composition and sharing of gut and vaginal microbiomes in mice and influenced cervical cancer development in an orthotopic tumor model. Antibiotics decreased richness and diversity indexes in the gut but increased them in the vagina. Some beneficial taxa, such as Bacteroides, Ruminococcaceae, and Lachnospiraceae increased their abundance in the vagina while other pathogenic species, such as Proteobacteria, were decreased. As a result of the changes, mice with greater richness and diversity of the vaginal microbiome after antibiotics exposure were less likely developed tumors. No association between richness and diversity of the gut microbiome and tumor development was identified.

Kinetics of Intratumoral Immune Cell Activation During Chemoradiation for Cervical Cancer

PURPOSE

Radiation therapy has direct cytotoxic effects on tumor-infiltrating lymphocytes, but it also has immune stimulatory effects that increase immune cell infiltration. The dynamics of these competing effects on immune cells at the site of the tumor are poorly characterized during chemoradiation treatment (CRT) because of the difficulty of obtaining consecutive tumor biopsies. We used a minimally invasive cervical cytobrushing method to analyze the kinetics of intratumoral immune cell changes in patients with cervical cancer during CRT.

METHODS AND MATERIALS

Cervical brushings were obtained from 20 patients with cervical cancer at baseline and during fractionated radiation therapy and cisplatin (weeks 1, 3, and 5). Matching peripheral blood mononuclear cells were obtained from 9 patients at the same time points. Cells were analyzed using multispectral flow cytometry to identify T cell and myeloid cell subsets and their activation status. Changes in immune cell subsets throughout treatment were calculated using matched-pair analysis with Wilcoxon rank sum test.

RESULTS

We observed a significant decline in CD3+ total T cells, as well as CD8+ and CD4+ T-cell subsets in the first week of treatment from baseline, followed by variable expansion at weeks 3 and 5. This coincided with higher levels of proliferating CD8+ T cells expressing Ki67 at week 3 of treatment. The percentages of activated CD8+ T cells expressing CD69 continuously increased over the course of treatment, whereas the percentage of activated CD11c+CD11b- dendritic cells was highest during the first week. Many of these changes were not observed in the blood.

CONCLUSIONS

Our results identified immune dynamic changes during CRT, indicating that CRT may be immune activating at the site of the tumor. This study also suggests the importance of sequential analyses of the local tumor microenvironment in addition to peripheral blood.