Therapeutic antibodies targeting programmed cell death 1 (PD-1) activate tumor-specific immunity and have shown remarkable efficacy in the treatment of melanoma. Yet, little is known about tumor ...cell-intrinsic PD-1 pathway effects. Here, we show that murine and human melanomas contain PD-1-expressing cancer subpopulations and demonstrate that melanoma cell-intrinsic PD-1 promotes tumorigenesis, even in mice lacking adaptive immunity. PD-1 inhibition on melanoma cells by RNAi, blocking antibodies, or mutagenesis of melanoma-PD-1 signaling motifs suppresses tumor growth in immunocompetent, immunocompromised, and PD-1-deficient tumor graft recipient mice. Conversely, melanoma-specific PD-1 overexpression enhances tumorigenicity, as does engagement of melanoma-PD-1 by its ligand, PD-L1, whereas melanoma-PD-L1 inhibition or knockout of host-PD-L1 attenuate growth of PD-1-positive melanomas. Mechanistically, the melanoma-PD-1 receptor modulates downstream effectors of mTOR signaling. Our results identify melanoma cell-intrinsic functions of the PD-1:PD-L1 axis in tumor growth and suggest that blocking melanoma-PD-1 might contribute to the striking clinical efficacy of anti-PD-1 therapy.
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•Human melanomas frequently contain PD-1-expressing cancer cell subpopulations•Inhibition of melanoma-PD-1 reduces tumor growth, independently of adaptive immunity•PD-1 overexpression and melanoma-PD-1:PD-L1 interactions promote tumor growth•Activation of the melanoma-PD-1 receptor modulates downstream mTOR signaling
PD-1/PD-L1 signaling has cell-intrinsic functions in certain types of mouse and human tumors, boosting cancer growth and promoting tumorigenesis. This suggests that immunotherapy with PD-1 blockers may produce an effect on tumor growth that is separate from their effect on the immune response.
Diabetes is a complex metabolic syndrome that is characterized by prolonged high blood glucose levels and frequently associated with life-threatening complications
. Epidemiological studies have ...suggested that diabetes is also linked to an increased risk of cancer
. High glucose levels may be a prevailing factor that contributes to the link between diabetes and cancer, but little is known about the molecular basis of this link and how the high glucose state may drive genetic and/or epigenetic alterations that result in a cancer phenotype. Here we show that hyperglycaemic conditions have an adverse effect on the DNA 5-hydroxymethylome. We identify the tumour suppressor TET2 as a substrate of the AMP-activated kinase (AMPK), which phosphorylates TET2 at serine 99, thereby stabilizing the tumour suppressor. Increased glucose levels impede AMPK-mediated phosphorylation at serine 99, which results in the destabilization of TET2 followed by dysregulation of both 5-hydroxymethylcytosine (5hmC) and the tumour suppressive function of TET2 in vitro and in vivo. Treatment with the anti-diabetic drug metformin protects AMPK-mediated phosphorylation of serine 99, thereby increasing TET2 stability and 5hmC levels. These findings define a novel 'phospho-switch' that regulates TET2 stability and a regulatory pathway that links glucose and AMPK to TET2 and 5hmC, which connects diabetes to cancer. Our data also unravel an epigenetic pathway by which metformin mediates tumour suppression. Thus, this study presents a new model for how a pernicious environment can directly reprogram the epigenome towards an oncogenic state, offering a potential strategy for cancer prevention and treatment.
Disorders in the regulatory arm of the adaptive immune system result in autoimmune‐mediated diseases. While systemic immunosuppression is the prevailing approach to manage them, it fails to achieve ...long‐lasting remission due to concomitant suppression of the regulatory arm and carries the risk of heightened susceptibility to infections and malignancies. Alopecia areata is a condition characterized by localized hair loss due to autoimmunity. The accessibility of the skin allows local rather than systemic intervention to avoid broad immunosuppression. It is hypothesized that the expansion of endogenous regulatory T cells (Tregs) at the site of antigen encounter can restore the immune balance and generate a long‐lasting tolerogenic response. A hydrogel microneedle (MN) patch is therefore utilized for delivery of CCL22, a Treg‐chemoattractant, and IL‐2, a Treg survival factor to amplify them. In an immune‐mediated murine model of alopecia, local bolstering of Treg numbers is shown, leading to sustained hair regrowth and attenuation of inflammatory pathways. In a humanized skin transplant mouse model, expansion of Tregs within human skin is confirmed without engendering peripheral immunosuppression. The patch offers high‐loading capacity and shelf‐life stability for prospective clinical translation. By harmonizing immune responses locally, the aim is to reshape the landscape of autoimmune skin disease management.
Alopecia areata is a condition characterized by hair loss due to autoimmunity. Expansion of endogenous regulatory T cells (Tregs) at the site of antigen encounter can restore the skin immune balance. Here, a hydrogel microneedle is utilized to amplify Tregs in a murine model of alopecia leading to sustained hair regrowth without engendering peripheral immunosuppression. This approach could reshape the landscape of autoimmune skin disease management.
DNA methylation at the 5 position of cytosine (5-mC) is a key epigenetic mark that is critical for various biological and pathological processes. 5-mC can be converted to 5-hydroxymethylcytosine ...(5-hmC) by the ten-eleven translocation (TET) family of DNA hydroxylases. Here, we report that “loss of 5-hmC” is an epigenetic hallmark of melanoma, with diagnostic and prognostic implications. Genome-wide mapping of 5-hmC reveals loss of the 5-hmC landscape in the melanoma epigenome. We show that downregulation of isocitrate dehydrogenase 2 (IDH2) and TET family enzymes is likely one of the mechanisms underlying 5-hmC loss in melanoma. Rebuilding the 5-hmC landscape in melanoma cells by reintroducing active TET2 or IDH2 suppresses melanoma growth and increases tumor-free survival in animal models. Thus, our study reveals a critical function of 5-hmC in melanoma development and directly links the IDH and TET activity-dependent epigenetic pathway to 5-hmC-mediated suppression of melanoma progression, suggesting a new strategy for epigenetic cancer therapy.
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► Loss of 5-hmC is an epigenetic hallmark of melanoma, with diagnostic/prognostic value ► Genome-wide mapping reveals a demolished 5-hmC landscape in human melanoma epigenome ► Downregulating IDH2 and TETs suggests a mechanism underlying 5-hmC loss in melanoma ► TET2 and IDH2 set the 5-hmC landscape, suppress melanoma growth, and increase survival
Genome-wide mapping of 5-hmC reveals that loss of 5-hmC is an epigenetic hallmark of melanoma, with diagnostic and prognostic implications. Downregulation of IDH2 and TET family enzymes likely underlies 5-hmC loss in melanoma, and rebuilding the 5-hmC landscape suppresses melanoma growth in animal models.
Cancer genetics has uncovered many tumor-suppressor and oncogenic pathways, but few alterations have revealed mechanisms involved in tumor spreading. Here, we examined the role of the third most ...significant chromosomal deletion in human melanoma that inactivates the adherens junction gene NECTIN1 in 55% of cases. We found that NECTIN1 loss stimulates melanoma cell migration in vitro and spreading in vivo in both zebrafish and human tumors specifically in response to decreased IGF1 signaling. In human melanoma biopsy specimens, adherens junctions were seen exclusively in areas with low IGF1 levels, but not in NECTIN1-deficient tumors. Our study establishes NECTIN1 as a major determinant of melanoma dissemination and uncovers a genetic control of the response to microenvironmental signals.
Cutaneous melanoma is a highly immunogenic malignancy that is surgically curable at early stages but life-threatening when metastatic. Here we integrate high-plex imaging, 3D high-resolution ...microscopy, and spatially resolved microregion transcriptomics to study immune evasion and immunoediting in primary melanoma. We find that recurrent cellular neighborhoods involving tumor, immune, and stromal cells change significantly along a progression axis involving precursor states, melanoma in situ, and invasive tumor. Hallmarks of immunosuppression are already detectable in precursor regions. When tumors become locally invasive, a consolidated and spatially restricted suppressive environment forms along the tumor-stromal boundary. This environment is established by cytokine gradients that promote expression of MHC-II and IDO1, and by PD1-PDL1-mediated cell contacts involving macrophages, dendritic cells, and T cells. A few millimeters away, cytotoxic T cells synapse with melanoma cells in fields of tumor regression. Thus, invasion and immunoediting can coexist within a few millimeters of each other in a single specimen.
The reorganization of the tumor ecosystem in primary melanoma is an excellent setting in which to study immunoediting and immune evasion. Guided by classic histopathology, spatial profiling of proteins and mRNA reveals recurrent morphologic and molecular features of tumor evolution that involve localized paracrine cytokine signaling and direct cell-cell contact. This article is highlighted in the In This Issue feature, p. 1397.
Cell division cycle 20 (CDC20) is a regulatory molecule and serves critical roles at multiple points of the cell cycle. Recent evidence indicates that CDC20 may serve an oncogenic role in a number of ...human cancer types. However, the role of CDC20 in primary cutaneous squamous cell carcinoma (cSCC) has not been studied, to the best of our knowledge. The aim of the present study was to investigate whether and how CDC20 is involved in the tumorigenesis of cSCC. The results revealed that CDC20 expression was significantly increased in cSCC tissues and cell lines, and its expression was associated with pathological differentiation. Downregulation of CDC20 inhibited cell proliferation, induced cell cycle arrest, promoted apoptosis and reduced migratory ability through inhibition of the Wnt/β-catenin signaling pathway. Furthermore, all-trans-retinoic acid treatment significantly downregulated CDC20 expression in cSCC. The present results revealed that CDC20 may serve a crucial role in human cSCC, and suggested that CDC20 may be a novel biomarker for the prevention, diagnosis and treatment of cSCC.
The steady rise in the incidence of cutaneous malignant melanoma and its inherently difficult-to-interpret histopathology continues to fuel an increasing demand for diagnostically and prognostically ...insightful adjunctive molecular tests among both clinicians and dermatopathologists. A number of DNA, RNA, and epigenetically based assays have now been developed and are at various stages of experimental and/or clinical use.
To examine the evidence for the utility and limitations of these leading candidates for the diagnosis and risk stratification of melanoma and related melanocytic neoplasms.
The available English medical literature was reviewed in the preparation of this manuscript.
Comparative genomic hybridization, fluorescence in situ hybridization, RNA-based gene expression profiling, and immunohistochemical assays for novel genetic and epigenetic markers will help bring diagnostic and prognostic accuracy to the assessment of melanocytic neoplasms.
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