Avoiding destruction by immune cells is a hallmark of cancer, yet how tumors ultimately evade control by natural killer (NK) cells remains incompletely defined. Using global transcriptomic and ...flow-cytometry analyses and genetically engineered mouse models, we identified the cytokine-TGF-β-signaling-dependent conversion of NK cells (CD49a
CD49b
Eomes
) into intermediate type 1 innate lymphoid cell (intILC1) (CD49a
CD49b
Eomes
) populations and ILC1 (CD49a
CD49b
Eomes
) populations in the tumor microenvironment. Strikingly, intILC1s and ILC1s were unable to control local tumor growth and metastasis, whereas NK cells favored tumor immunosurveillance. Experiments with an antibody that neutralizes the cytokine TNF suggested that escape from the innate immune system was partially mediated by TNF-producing ILC1s. Our findings provide new insight into the plasticity of group 1 ILCs in the tumor microenvironment and suggest that the TGF-β-driven conversion of NK cells into ILC1s is a previously unknown mechanism by which tumors escape surveillance by the innate immune system.
Evolution of tumor cell phenotypes promotes heterogeneity and therapy resistance. Here we found that induction of CD73, the enzyme that generates immunosuppressive adenosine, is linked to melanoma ...phenotype switching. Activating MAPK mutations and growth factors drove CD73 expression, which marked both nascent and full activation of a mesenchymal-like melanoma cell state program. Proinflammatory cytokines like TNFα cooperated with MAPK signaling through the c-Jun/AP-1 transcription factor complex to activate CD73 transcription by binding to an intronic enhancer. In a mouse model of T-cell immunotherapy, CD73 was induced in relapse melanomas, which acquired a mesenchymal-like phenotype. We also detected CD73 upregulation in melanoma patients progressing under adoptive T-cell transfer or immune checkpoint blockade, arguing for an adaptive resistance mechanism. Our work substantiates CD73 as a target to combine with current immunotherapies, but its dynamic regulation suggests limited value of CD73 pretreatment expression as a biomarker to stratify melanoma patients.
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Recent studies revealed trajectories of mutational events in early melanomagenesis, but the accompanying changes in gene expression are far less understood. Therefore, we performed a comprehensive ...RNA-seq analysis of laser-microdissected melanocytic nevi (n = 23) and primary melanoma samples (n = 57) and characterized the molecular mechanisms of early melanoma development. Using self-organizing maps, unsupervised clustering, and analysis of pseudotime (PT) dynamics to identify evolutionary trajectories, we describe here two transcriptomic types of melanocytic nevi (N1 and N2) and primary melanomas (M1 and M2). N1/M1 lesions are characterized by pigmentation-type and MITF gene signatures, and a high prevalence of NRAS mutations in M1 melanomas. N2/M2 lesions are characterized by inflammatory-type and AXL gene signatures with an equal distribution of wild-type and mutated BRAF and low prevalence of NRAS mutations in M2 melanomas. Interestingly, N1 nevi and M1 melanomas and N2 nevi and M2 melanomas, respectively, cluster together, but there is no clustering in a stage-dependent manner. Transcriptional signatures of M1 melanomas harbor signatures of BRAF/MEK inhibitor resistance and M2 melanomas harbor signatures of anti-PD-1 antibody treatment resistance. Pseudotime dynamics of nevus and melanoma samples are suggestive for a switch-like immune-escape mechanism in melanoma development with downregulation of immune genes paralleled by an increasing expression of a cell cycle signature in late-stage melanomas. Taken together, the transcriptome analysis identifies gene signatures and mechanisms underlying development of melanoma in early and late stages with relevance for diagnostics and therapy.
The activating receptor CD226 is expressed on lymphocytes, monocytes, and platelets and promotes anti-tumor immunity in pre-clinical models. Here, we examined the role of CD226 in the function of ...tumor-infiltrating lymphocytes (TILs) and resistance to immunotherapy. In murine tumors, a large proportion of CD8+ TILs had decreased surface expression of CD226 and exhibited features of dysfunction, whereas CD226hi TILs were highly functional. This correlation was seen also in TILs isolated from HNSCC patients. Mutation of CD226 at tyrosine 319 (Y319) led to increased CD226 surface expression, enhanced anti-tumor immunity and improved efficacy of immune checkpoint blockade (ICB). Mechanistically, tumor-derived CD155, the ligand for CD226, initiated phosphorylation of Y319 by Src kinases, thereby enabling ubiquitination of CD226 by CBL-B, internalization, and proteasomal degradation. In pre-treatment samples from melanoma patients, CD226+CD8+ T cells correlated with improved progression-free survival following ICB. Our findings argue for the development of therapies aimed at maintaining the expression of CD226.
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•Dysfunctional CD226-negative T cells accumulate in mouse and human tumors•CD155 induces ubiquitination via CBL-B and proteasomal degradation of CD226•A mutation of Y319 maintains CD226 expression and improves anti-tumor immunity•ICB-therapy in melanoma patients relies on the presence of CD226+CD8+ T cells
Braun et al. find that CD155 on tumor cells drives the proteasomal degradation of the activating receptor CD226 on tumor-infiltrating CD8+ T cells, thus promoting immune evasion and resistance to cancer immunotherapy.
Increasing evidence exists for the role of immunosuppressive adenosine in promoting tumor growth and spread in a number of cancer types, resulting in poor clinical outcomes. In this study, we ...assessed whether the CD73-adenosinergic pathway is active in melanoma patients and whether adenosine restricts the efficacy of clinically approved targeted therapies for commonly mutated BRAF
melanoma. In AJCC stage III melanoma patients, CD73 expression (the enzyme that generates adenosine) correlated significantly with patients presenting nodal metastatic melanoma, suggesting that targeting this pathway may be effective in advanced stage disease. In addition, dabrafenib and trametinib treatment of CD73
BRAF
-mutant melanomas caused profound CD73 downregulation in tumor cells. Inhibition of BRAF and MEK in combination with the A2A adenosine receptor provided significant protection against tumor initiation and metastasis formation in mice. Our results suggest that targeting adenosine may enhance therapeutic responses for melanoma patients receiving targeted or immune-based therapies.
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Frequent testing of large population groups combined with contact tracing and isolation measures will be crucial for containing Coronavirus Disease 2019 outbreaks. Here we present LAMP-Seq, a ...modified, highly scalable reverse transcription loop-mediated isothermal amplification (RT-LAMP) method. Unpurified biosamples are barcoded and amplified in a single heat step, and pooled products are analyzed en masse by sequencing. Using commercial reagents, LAMP-Seq has a limit of detection of ~2.2 molecules per µl at 95% confidence and near-perfect specificity for severe acute respiratory syndrome coronavirus 2 given its sequence readout. Clinical validation of an open-source protocol with 676 swab samples, 98 of which were deemed positive by standard RT-qPCR, demonstrated 100% sensitivity in individuals with cycle threshold values of up to 33 and a specificity of 99.7%, at a very low material cost. With a time-to-result of fewer than 24 h, low cost and little new infrastructure requirement, LAMP-Seq can be readily deployed for frequent testing as part of an integrated public health surveillance program.
Target genes of the protooncogene c-myc are implicated in cell cycle and growth control, yet the linkage of both is still unexplored. Here, we show that the products of the nucleolar target genes ...Pes1 and Bop1 form a stable complex with a novel member, WDR12 (PeBoW complex). Endogenous WDR12, a WD40 repeat protein, is crucial for processing of the 32S precursor ribosomal RNA (rRNA) and cell proliferation. Further, a conditionally expressed dominant-negative mutant of WDR12 also blocks rRNA processing and induces a reversible cell cycle arrest. Mutant WDR12 triggers accumulation of p53 in a p19ARF-independent manner in proliferating cells but not in quiescent cells. Interestingly, a potential homologous complex of Pes1-Bop1-WDR12 in yeast (Nop7p-Erb1p-Ytm1p) is involved in the control of ribosome biogenesis and S phase entry. In conclusion, the integrity of the PeBoW complex is required for ribosome biogenesis and cell proliferation in mammalian cells.
Retinoids play key roles in differentiation, growth arrest, and apoptosis and are increasingly being used in the clinic for the treatment of a variety of cancers, including neuroblastoma. Here, using ...a large-scale RNA interference-based genetic screen, we identify
ZNF423 (also known as
Ebfaz,
OAZ, or
Zfp423) as a component critically required for retinoic acid (RA)-induced differentiation. ZNF423 associates with the RARα/RXRα nuclear receptor complex and is essential for transactivation in response to retinoids. Downregulation of
ZNF423 expression by RNA interference in neuroblastoma cells results in a growth advantage and resistance to RA-induced differentiation, whereas overexpression of
ZNF423 leads to growth inhibition and enhanced differentiation. Finally, we show that low
ZNF423 expression is associated with poor disease outcome in neuroblastoma patients.
Retinoic acid (RA) induces differentiation of neuroblastoma cells in vitro and is used with variable success to treat aggressive forms of this disease. This variability in clinical response to RA is ...enigmatic, as no mutations in components of the RA signaling cascade have been found. Using a large-scale RNAi genetic screen, we identify crosstalk between the tumor suppressor NF1 and retinoic acid-induced differentiation in neuroblastoma. Loss of NF1 activates RAS-MEK signaling, which in turn represses ZNF423, a critical transcriptional coactivator of the retinoic acid receptors. Neuroblastomas with low levels of both NF1 and ZNF423 have extremely poor outcome. We find NF1 mutations in neuroblastoma cell lines and in primary tumors. Inhibition of MEK signaling downstream of NF1 restores responsiveness to RA, suggesting a therapeutic strategy to overcome RA resistance in NF1-deficient neuroblastomas.
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▸ Loss of NF1 blocks retinoic acid (RA) induced differentiation in neuroblastoma ▸ Loss of NF1 represses the RA receptor coactivator ZNF423 through RAS-MEK signaling ▸ Mutations and low expression of NF1 occur in primary neuroblastomas ▸ MEK inhibitors restore the RA response in NF1-deficient neuroblastomas
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