The gut microbiota influences both local and systemic inflammation. Inflammation contributes to development, progression and treatment of cancer, but it remains unclear whether commensal bacteria affect inflammation in the sterile tumor microenvironment. Here we show that disruption of the microbiota impairs the response of subcutaneous tumors to CpG-oligonucleotide immunotherapy and platinum chemotherapy. In antibiotic-treated or germ-free mice, tumor-infiltrating myeloid-derived cells responded poorly to therapy, resulting in lower cytokine production and tumor necrosis after CpG-oligonucleotide treatment, and deficient production of reactive oxygen species and cytotoxicity following chemotherapy. Thus, optimal responses to cancer therapy require an intact commensal microbiota that mediates its effects by modulating myeloid-derived cell functions in the tumor microenvironment. These findings underscore the importance of the microbiota in the outcome of disease treatment.
Commensal bacteria control cancer response to therapy by modulating the tumor microenvironment.
Specimen part
View SamplesCharacterized by striking metastatic propensity and chemoresistance, melanoma is among the most lethal cutaneous malignancies. The transcription factor ATF2 was shown to elicit oncogenic activities in melanoma, and its inhibition attenuates melanoma development. Here, a mouse model engineered to express a transcriptionally inactive form of Atf2 (Atf2?8,9) was found to be sufficient to induce nevi formation and, when crossed with BrafV600E animals, to promote melanoma development. The cross of Atf2?8,9 with BrafV600E;Pten-/- mice augmented pigmentation, tumorigenicity, and metastasis. Similar to mouse Atf2?8,9, the human ATF2 splice variant 5 enhanced growth and migration capacity of cultured melanoma and immortalized melanocytes. Induced Melan-A, CXCL9, S100A8, CCR7 expression, seen in Atf2?8,9-driven tumors associate with their enhanced pigmentation, immune infiltration and propensity to metastasize. Notably, elevated ATF2SV5 expression in melanoma specimens coincided with poor prognosis. The gain-of-function activity elicited by the truncated ATF2 form offers unexpected insight into mechanisms underlying melanoma development and progression. Overall design: Compared silencing of ATF2SV5 in H3A cells vs. silencing of ATF2WT via Ampliseq whole transcriptome analysis on the Ion Proton
A Transcriptionally Inactive ATF2 Variant Drives Melanomagenesis.
Specimen part, Subject
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