Molly B. El Alam

Linking Microbiome Diversity and Immune Profiles in Ethiopian Patients With Cervical Cancer

PURPOSE This study investigates the interplay between T-cell receptor (TCR) immune characteristics and microbiome profiles to explore the relationship between immune diversity and microbial composition in cervical samples from Ethiopia. METHODS Cervical specimens were collected from patients at Tikur Anbessa Specialized Hospital in Addis Ababa, and rural Butajira, south-central Ethiopia. Patient data, including age, human papillomavirus status, pathology, and TCR immune characteristics, were analyzed with a focus on the interactions between TCR profiles and microbiome compositions in malignant samples. RESULTS Three distinct TCR profiles were identified: Group 1 (TCR active) exhibited features of active immune engagement, including high diversity, clonal expansion, and repertoire richness. Group 2 (TCR restricted) showed reduced TCR diversity and expansion, suggesting a restricted repertoire. Group 3 (TCR balanced) had moderate diversity and clonal activity. TCR repertoire groups were linked with microbial diversity, with Group 1 (TCR active) showing the highest number of microbes (high operational taxonomic units and microbial diversity). Maximum TCR clonal expansion positivity associated with microbial richness, while Group 3 (TCR balanced) was linked to reduced microbial alpha diversity. Taxonomic analysis revealed specific organisms enriched in TCR repertoire group. CONCLUSION Variations in TCR profiles are linked to distinct microbial environments in cervical cancer with greater microbial richness in patients with greater maximum productive frequency. These findings underscore the interplay between TCR diversity, microbiome composition, and malignancy, offering insights into the potential implications for microbiome-targeted therapies and prognostic biomarkers in cervical cancer.

Gut microbiome diversity is an independent predictor of survival in cervical cancer patients receiving chemoradiation

AbstractDiversity of the gut microbiome is associated with higher response rates for cancer patients receiving immunotherapy but has not been investigated in patients receiving radiation therapy. Additionally, current studies investigating the gut microbiome and outcomes in cancer patients may not have adjusted for established risk factors. Here, we sought to determine if diversity and composition of the gut microbiome was independently associated with survival in cervical cancer patients receiving chemoradiation. Our study demonstrates that the diversity of gut microbiota is associated with a favorable response to chemoradiation. Additionally, compositional variation among patients correlated with short term and long-term survival. Short term survivor fecal samples were significantly enriched in Porphyromonas, Porphyromonadaceae, and Dialister, whereas long term survivor samples were significantly enriched in Escherichia Shigella, Enterobacteriaceae, and Enterobacteriales. Moreover, analysis of immune cells from cervical tumor brush samples by flow cytometry revealed that patients with a high microbiome diversity had increased tumor infiltration of CD4+ lymphocytes as well as activated subsets of CD4 cells expressing ki67+ and CD69+ over the course of radiation therapy. Modulation of the gut microbiota before chemoradiation might provide an alternative way to enhance treatment efficacy and improve treatment outcomes in cervical cancer patients.

Tumor-resident Lactobacillus iners confer chemoradiation resistance through lactate-induced metabolic rewiring

Tumor microbiota can produce active metabolites that affect cancer and immune cell signaling, metabolism, and proliferation. Here, we explore tumor and gut microbiome features that affect chemoradiation response in patients with cervical cancer using a combined approach of deep microbiome sequencing, targeted bacterial culture, and in vitro assays. We identify that an obligate L-lactate-producing lactic acid bacterium found in tumors, Lactobacillus iners, is associated with decreased survival in patients, induces chemotherapy and radiation resistance in cervical cancer cells, and leads to metabolic rewiring, or alterations in multiple metabolic pathways, in tumors. Genomically similar L-lactate-producing lactic acid bacteria commensal to other body sites are also significantly associated with survival in colorectal, lung, head and neck, and skin cancers. Our findings demonstrate that lactic acid bacteria in the tumor microenvironment can alter tumor metabolism and lactate signaling pathways, causing therapeutic resistance. Lactic acid bacteria could be promising therapeutic targets across cancer types.

Exploratory analysis of the cervix tumoral HPV antigen-specific T-cell repertoire during chemoradiation and after brachytherapy

Chemoradiation (CRT) may modulate the immune milieu as an in-situ vaccine. Rapid dose delivery of brachytherapy has unclear impact on T-cell repertoires. HPV-associated cancers express viral oncoproteins E6/E7, which enable tracking antigen/tumor-specific immunity during CRT. Thirteen cervical cancer patients on a multi-institutional prospective protocol from 1/2020-1/2023 underwent standard-of-care CRT with pulsed-dose-rate brachytherapy boost (2 fractions). Cervix swabs at various timepoints underwent multiplex DNA deep sequencing of the TCR-β/CDR3 region with immunoSEQ. Separately, HPV-responsive T-cell clones were also expanded ex vivo. Statistical analysis was via Mann-Whitney-U. TCR productive clonality, templates, frequency, or rearrangements increased post-brachytherapy in 8 patients. Seven patients had E6/E7-responsive evolution over CRT with increased productive templates (ranges: 1.2-50.2 fold-increase from baseline), frequency (1.2-1.7), rearrangements (1.2-40.2), and clonality (1.2-15.4). Five patients had HPV-responsive clonal expansion post-brachytherapy, without changes in HPV non-responsive clones. Epitope mapping revealed VDJ rearrangements targeting cervical cancer-associated antigens in 5 patients. The only two patients with disease recurrence lacked response in all metrics. A lack of global TCR remodeling correlated with worse recurrence-free survival, p = 0.04. CRT and brachytherapy alters the cervical cancer microenvironment to facilitate the expansion of specific T-cell populations, which may contribute to treatment efficacy.