Interaction of bacterial genera associated with therapeutic response to immune checkpoint PD-1 blockade in a United States cohort

BACKGROUND

Recent studies show that human gut microbial composition can determine whether a patient is a responder or non-responder to immunotherapy but have not identified a common microbial signal shared by responding patients. The functional relationship between immunity, intestinal microbiota, and NSCLC response to immune checkpoint inhibitor/inhibition (ICI) in an American cohort remains unexplored.

METHODS

RNAlater-preserved fecal samples were collected from 65 pre-treatment (baseline) and post-treatment stage III/IV NSCLC patients undergoing ICI therapy, categorized as responders or non-responders according to RECIST criteria. Pooled and individual responder and non-responder microbiota were transplanted into a gnotobiotic mouse model of lung cancer and treated with ICIs. 16S rDNA and RNA sequencing was performed on patient fecal samples, 16S rDNA sequencing on mouse fecal samples, and flow cytometric analysis on mouse tumor tissue.

RESULTS

Responder patients have both a different microbial community structure than non-responders (P = 0.004) and a different bacterial transcriptome (PC2 = 0.03) at baseline. Taxa significantly enriched in responders include amplicon sequence variants (ASVs) belonging to the genera Ruminococcus, Akkermansia, and Faecalibacterium. Pooled and individual responder microbiota transplantation into gnotobiotic mice decreased tumor growth compared to non-responder colonized mice following ICI (P = 0.023, P = 0.019, P = 0.008, respectively). Responder tumors showed an increased anti-tumor cellular phenotype following ICI treatment. Responder mice are enriched with ASVs belonging to the genera Bacteroides, Blautia, Akkermansia, and Faecalibacterium. Overlapping taxa mapping between human and mouse cohorts correlated with tumor size and weight revealed a network highlighting responder-associated ASVs belonging to the genera Colidextribacter, Frisingicoccus, Marvinbryantia, and Blautia which have not yet been reported.

CONCLUSIONS

The role of isolate-specific function and bacterial gene expression in gut microbial-driven responsiveness to ICI has been underappreciated. This work supports further investigation using isolate-driven models to characterize the mechanisms underlying this phenomenon.

A Customized At-Home Stool Collection Protocol for Use in Microbiome Studies Conducted in Cancer Patient Populations

Fecal specimen collection in the clinical setting is often unfeasible for large population studies, especially because cancer patients on immunotherapy often experience constipation. A method for constructing and using an at-home stool collection kit designed for epidemiological studies in cancer patients is presented. Participation and compliance rates of the collection kit among late-stage cancer patients from an ongoing, longitudinal study are also discussed. The kit includes three different media on which samples are introduced. Using one stool sample, patients collect specimens by smearing stool onto a fecal occult blood test (FOBT) card, containing three slides for collection. Additional specimens from the same stool sample are added to one tube containing 8 mL of RNAlater preservative and one tube containing 8 mL of 95% ethanol. Stool specimens are stored at room temperature and returned to researchers within 3 days of collection. The purpose of this kit is to yield stool specimens on a variety of media that can be preserved for extended periods of time at room temperature and are compatible with multi-omics approaches for specimen analysis. According to leading microbiome researchers and published literature, each collection method is considered optimal for use in large epidemiological studies. Moreover, the kit is comprised of various components that make stool collection easy, so as not to burden the patient and hence maximize overall compliance. Use of this kit in a study of late-stage lung cancer patients had a participation rate of 83% and baseline compliance rate of 58%.

Abstract 3326: Mucositis, candidiasis, and associations with the oral microbiome in treatment naive patients with oropharyngeal cancer

Purpose: Oropharyngeal cancer (OPC) incidence continues to increase dramatically in the US. Accumulating evidence suggests that oral microbiota (communities of microorganisms that reside in the oral cavity) may influence cancer treatment-related toxicities. We sought to examine the composition and diversity of oral microbiota in OPC patients prior to treatment, and identify associations between oral microbiota and subsequent development of oral mucositis (inflammation of mucous membranes) and candidiasis (fungal infection with Candida yeast).

Methods: 60 newly diagnosed, treatment naïve, OPC patients were recruited from Moffitt Cancer Center (2015-2017). Patients provided mouthwash-based oral gargles before starting chemoradiation or radiation. DNA was isolated using the QIAGEN DNeasy PowerSoil kit, and the V1-V3 region of the bacterial 16S rRNA gene was sequenced. An operational taxonomic unit table was generated and Ribosomal Database Project Classifier used to assign taxonomy. The development of oral mucositis (no/mild vs. severe) and candidiasis (no vs. yes) during treatment was abstracted from medical records. Comparisons of bacterial relative abundance (Mann Whitney U), alpha diversity (Chao1, Shannon, and Simpson), and beta diversity (Bray-Curtis) were performed in R and its extension (Phyloseq).

Results: Of 60 OPC patients, 65% were stage IV, 48% tonsillar and 42% base of tongue, and 40% never smokers. Pre-treatment levels of genus Klebsiella and class Gammaproteobacteria were significantly greater in the oral cavity of patients who had no/mild mucositis vs. those who developed severe mucositis (p<0.04). Genera Atopobium and Mogibacterium, as well as families Coriobacteriaceae and Clostridiales Incertae Sedis, were significantly more abundant in patients who did not develop oral candidiasis compared to those who did (p<0.04). Oral bacterial alpha diversity (intra-subject) was higher in patients who developed vs. did not develop severe mucositis, and lower in patients who developed vs. did not develop candidiasis during treatment. Analyses of beta diversity (inter-subject) showed that the microbial community structures were not significantly different by mucositis or candidiasis development.

Conclusions: Microbiome profiling may hold promise as a prognostic biomarker of treatment-related toxicities. Several potentially predictive taxa were identified to be differentially abundant in OPC patients who subsequently developed oral mucositis or candidiasis. Future analyses will evaluate the role of oral microbial resilience (the rate of recovery after disturbance) using oral specimens collected 3 mo. after treatment. Translational research focused on understanding how oral microbiota influence local immune and inflammatory responses may aid in the development of microbiota-based interventions to minimize adverse events.

Citation Format: Christine M. Pierce, Stephanie Hogue, Shirlene Paul, Bo-Young Hong, Wildson Vieira da Silva, Maria F. Gomez, Anna R. Giuliano, Jimmy J. Caudell, George M. Weinstock. Mucositis, candidiasis, and associations with the oral microbiome in treatment naive patients with oropharyngeal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3326.

Ansiedade infantil e instrumentos de avaliação: uma revisão sistemática

OBJETIVO: Fazer um levantamento dos principais instrumentos de avaliação da ansiedade em crianças, quando surgiram, que tipos de estudos foram realizados com os mesmos, verificando os países de maior incidência de aplicação dos testes, bem como a realidade dos instrumentos no Brasil. MÉTODOS: Revisão sistemática em bancos de dados eletrônicos _ Psychoinfo (1940 _ Maio 2002), Psyclit (1887 _ maio 2002), Medline (1966 _ maio 2002) e Eric (1966 _ maio 2002). Busca de informações fundamentada em comunicação pessoal e capítulos de livros. O critério de inclusão foi: estudos realizados com crianças, nos quais o construto ansiedade foi avaliado por algum instrumento psicométrico. Critérios de exclusão: artigos alusivos à pesquisa com adolescentes, adultos e animais; artigos utilizando testes projetivos ou sem a indicação do instrumento. Os artigos indexados repetidamente em dois ou mais bancos foram considerados apenas uma vez. RESULTADOS: Esta revisão apontou 1.911 estudos que utilizaram, no mínimo, um instrumento de avaliação de ansiedade; 118 instrumentos foram usados para este fim. Conclusões: Atualmente, existem inúmeros instrumentos disponíveis para avaliação da ansiedade em crianças; entretanto, no Brasil, a escala disponível no mercado está desatualizada e as mais modernas encontram-se somente em centros clínicos acadêmicos.