Search bioRxiv⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/548818

Exosome-mediated MIR211 modulates tumor microenvironment via the DUSP6-ERK5 axis and contributes to BRAFV600E inhibitor resistance in melanoma.

Lee, B.·Sahoo, A.·Marchica, J.·Sawada, J.·Sahoo, S.·Layng, F. I. A. L.·Finlay, D.·Mazar, J.·Joshi, P.·Komatsu, M.·Vuori, K.·Powis, G.·de Jong, P. R.·Ray, A.·Perera, R. J.
View original source ↗Export metadata ↓

Abstract

The microRNA MIR211 is an important regulator of melanoma tumor cell behavior. Previous studies suggested that in certain tumors, MIR211 acted as a tumor suppressor while in others it behaved as an oncogenic regulator. When MIR211 is expressed in BRAFV600E-mutant A375 melanoma cells in mouse xenografts, it promotes aggressive tumor growth accompanied by increased cellular proliferation and angiogenesis. We demonstrate that MIR211 is transferred to adjacent cells in the tumor micro-environment via exosomes. Cross-species genome-wide transcriptomic analysis showed that human tumor-derived MIR211 interacts with the mouse transcriptome in the tumor microenvironment, and activates ERK5 signaling in human tumor cells via the modulation of a feedback loop. Human miR211 directly inhibits human DUSP6 protein phosphatase at the post-transcriptional level. We provide support for the hypothesis that DUSP6 inhibition conferred resistance of the human tumor cells to the BRAF inhibitor vemurafenib and to the MEK inhibitor cobimetinib, with associated increases in ERK5 phosphorylation. These findings are consistent with a model in which MIR211 regulates melanoma tumor proliferation and BRAF inhibitor resistance by inducing ERK5 signaling within the complex tumor microenvironment. We propose that the MIR211-ERK5 axis represents an important and sensitive regulatory arm in melanoma with potential theranostic applications.

Explore related subjects

cancer biologyPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Lee, B., Sahoo, A., Marchica, J., Sawada, J., Sahoo, S., Layng, F. I. A. L., Finlay, D., Mazar, J., Joshi, P., Komatsu, M., Vuori, K., Powis, G., de Jong, P. R., Ray, A., Perera, R. J.. 2019-02-13. Exosome-mediated MIR211 modulates tumor microenvironment via the DUSP6-ERK5 axis and contributes to BRAFV600E inhibitor resistance in melanoma.. https://doi.org/10.1101/548818

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

BCL10 Gain-of-Function Impairs Germinal Center Participation by Naive B Cells and Cooperates with BCL6 to Drive Extrafollicular Diffuse Large B-Cell Lymphoma

BCL10 gain-of-function (GoF) mutations occur in diffuse large B-cell lymphoma (DLBCL) cases of the BN2/C1 molecular subgroup. These alterations activate CARD11-BCL10-MALT1 (CBM) signaling and drive resistance to multiple drug classes, but their role in disease pathogenesis is incompletely understood. In particular, interactions between BCL10 GoF and additional DLBCL oncogenes are undefined. Here, we show BCL10 GoF in naive B cells blocks their participation in germinal center (GC) reactions and permits transformation to DLBCL with a non-GC B-cell phenotype. Most clinical cases with BCL10 GoF also carry translocation of the BCL6 proto-oncogene, and we show that co-activation of these two lesions together promotes pronounced oncogenic synergy. Detailed single-cell analyses of underlying premalignant B-cell populations revealed expansion of extrafollicular memory B cells whose gene-expression program remains prominent in resulting lymphomas in both the mouse and corresponding human tumors. We therefore define a novel role for BCL10 activating mutations in enabling BCL6 lymphomagenesis.

cancer biology↗
bioRxiv2026

Response to azacitidine and the TIM-3 inhibitor, sabatolimab, in MDS and CMML is associated with distinct immune and antigen-presentation states

Targeting the immune checkpoint TIM-3 is of interest in myeloid neoplasms, yet the hematopoietic and immune changes associated with anti-TIM-3 therapy remain poorly characterized. We used single-cell RNA sequencing to profile bone marrow (BM) and peripheral blood from patients with myelodysplastic syndrome (MDS) and chronic myelomonocytic leukemia (CMML) treated with the hypomethylating agent azacitidine combined with sabatolimab, a monoclonal antibody targeting TIM-3, and integrated Human Cell Atlas reference datasets for comparison. CITE-seq profiling showed that TIM-3 was predominantly expressed on dendritic cells and NK cells, with variable expression across other populations, including CD34 cells and CD8 T cells. At baseline, we identified a population of CD34 myeloid-biased progenitors specific to MDS/CMML samples ("HSPC-like") characterized by inflammatory gene expression programs and features of impaired differentiation. In MDS, elevated baseline HLA class II expression across hematopoietic stem and progenitor cells (HSPCs), HSPC-like cells, and multiple myeloid populations was associated with response. Consistent with this finding, trajectory analysis suggested that nonresponders bypassed HLA class II-high states during myeloid differentiation. In MDS, the presence of distinct CD8 T-cell populations and increased interferon-response programs in CD8 T and NK cells at baseline was also associated with response. In both MDS and CMML, treatment among responders was associated with contraction of BM CD8 and CD4 T-cell populations characterized by type I interferon-responsive and inflammatory programs, including IFIT1, IFIT2, and TNF, along with expansion of a distinct GZMH/IFITM1-expressing cytotoxic CD8 T-cell population. Together, these findings identify baseline antigen-presentation and immune-response programs associated with therapeutic response and reveal coordinated remodeling of myeloid and lymphoid compartments during azacitidine/sabatolimab treatment in MDS and CMML.

cancer biology↗
bioRxiv2026

Adaptation of breast cancer cells to serum-free defined medium reveals changes in proliferation, adhesion, and lipid metabolism

Cancer cell metabolic dependencies are strongly influenced by nutrient availability, yet conventional culture conditions contain non-physiological nutrient concentrations and poorly defined serum components that may obscure metabolic vulnerabilities. Here, we investigated the adaptation of three breast cancer cell lines to physiologically relevant, serum-free defined medium (DM). Using a stepwise reduction in fetal bovine serum (FBS), we evaluated proliferation, adhesion, morphology, and transcriptional changes in HER2-positive SK-BR-3, triple-negative MDA-MB-231, and ER-positive/HER2-positive BT-474 cells. The three cell lines differed substantially in their ability to adapt to serum-free conditions. MDA-MB-231 cells adapted readily, maintaining proliferation and adhesion without exogenous substrate coatings. SK-BR-3 cells also achieved sustained proliferation in serum-free DM, but required a serum-derived coating to maintain adhesion. In contrast, BT-474 cells failed to sustain adhesion and proliferation following complete serum withdrawal, although they remained proliferative in medium containing 1% FBS. Adapted cells retained characteristic HER2 or vimentin expression despite changes in morphology and proliferation. RNA sequencing revealed extensive transcriptional remodeling, including reduced expression of cell-cycle-associated programs in SK-BR-3 cells and enrichment of cholesterol homeostasis gene sets in SK-BR-3 and MDA-MB-231 cells. Expression of cholesterol regulatory genes, including SREBF2, HMGCR, and LDLR, increased across all three lines. Together, these findings highlight cell-line-specific adhesion requirements and shared metabolic responses to serum withdrawal, establishing a framework for developing defined culture systems to investigate cancer metabolic dependencies through genetic screening.

cancer biology↗