Biology subjects

Meylan, E.

Publications and source records attributed to Meylan, E..

3 recordsLinked to original sources

bioRxiv2021

Low STING expression in a transplantable KrasG12D/P53ko lung cancer model contributes to SiglecF+ neutrophil and CD103+Treg accumulation in tumors

Lung cancer is the leading cause of mortality by cancer worldwide. Non-small cell lung cancer is the most common type of lung cancer and mutations in the KRAS gene are frequently found in this pathology. While immune checkpoint inhibitors are providing new hope for lung cancer care, only a subset of patients show durable benefit from these new therapies designed to drive an efficient anti-tumor immune response. Hence, it is crucial to better understand the mechanisms through which the tumor immune microenvironment is established in lung tumors. Using bioinformatics, we observed that high expression of the STimulator of INterferon Gene (STING) associates with a longer overall survival specifically in KRAS mutant cancer patients. In lung cancer cell lines, STING expression is linked to interferon response and epithelial-to-mesenchymal transition. Because STING activation in immune cells of the tumor microenvironment using specific agonists is an emerging strategy to trigger an anti-tumor immune response, we took advantage of two transplantable models of Kras driven lung cancer, expressing high or low levels of STING, to investigate the function of STING directly in cancer cells in vivo. We observed that high-STING expression and constitutive STING signaling were critical for transplanted tumor formation rather than playing a major role in tumor immunogenicity. Besides, low-STING expression in cancer cells is associated with an immunosuppressive tumor microenvironment characterized by the accumulation of tumor promoting SiglecF+ neutrophils and CD103+ regulatory T cells. In that model, knocking out STING increased the early response to anti-PD1 treatment. We conclude that low-STING expression in cancer cells might confer them an independence from pro-inflammatory signals and a greater immunosuppressive capability and aggressiveness.

cancer biology↗

bioRxiv2018

Efficient and specific Ly6G+ cell depletion: A change in the current practices toward more relevant functional analyses of neutrophils

Neutrophils orchestrate the innate immune response against microorganisms and are increasingly recognized to modulate cancer development in primary tumors and metastases. To address their function in vivo, different approaches are used, the most common ones relying on antibody-mediated neutrophil depletion. By comparing the effects of two widely used antibodies, we demonstrate a strong efficacy but a lack of specificity for anti-Gr1. In contrast, anti-Ly6G lacks neutrophil-depletion capacity in C57BL/6 mice, which can be explained by an insufficient celerity of neutrophil clearance that is counterbalanced by exacerbated mobilization of immature cells. When combined with a secondary antibody, anti-Ly6G treatment results in specific and efficient neutrophil depletion. Using a mouse model of lung adenocarcinoma, we demonstrate the efficacy of this new approach to diminish primary tumor growth and propose the existence of a local intercellular communication between neutrophils and alveolar macrophages that fosters regulatory T cell proliferation in lung cancer.

immunology↗

bioRxiv2017

RANKL Signaling Sustains Primary Tumor Growth In Genetically Engineered Mouse Models Of Lung Adenocarcinoma

HypothesisNon-small cell lung cancer (NSCLC) is the leading cause of cancer mortality. Recent retrospective clinical analyses suggest that blocking the receptor activator of NF-{kappa}B (RANK) signaling pathway inhibits the growth of NSCLC and might represent a new treatment strategy.\n\nMethodsRANK and RANKL expression in human lung adenocarcinoma was interrogated from publicly available gene expression datasets. Several genetically engineered mouse models were used to evaluate treatment efficacy of RANK-Fc to block RANKL, with primary tumor growth measured longitudinally using micro-computed tomography. A combination of RANKL blockade with cisplatin was tested to mirror an ongoing clinical trial.\n\nResultsIn human lung adenocarcinoma datasets, RANKL expression was associated with decreased survival and KRAS mutation, with the highest levels in tumors with co-occurring KRAS and LKB1 mutations. In KrasLSL-G12D/WT, KrasLSL-G12D/WT; Lkb1Flox/Flox and KrasLSL-G12D/WT; p53Flox/Flox mouse models of lung adenocarcinoma, we monitored an impaired progression of tumors upon RANKL blockade. Despite elevated expression of RANKL and RANK in immune cells, treatment response was not associated with major changes in the tumor immune microenvironment. Combined RANK-Fc with cisplatin revealed increased efficacy compared to single agents.\n\nConclusionsRANKL blocking agents impair the growth of primary lung tumors in several mouse models of lung adenocarcinoma, and suggest that patients with KRAS mutant lung tumors will benefit from such treatments.

cancer biology↗