Background

Coronavirus disease-2019 (COVID-19) has been associated with cutaneous findings, some being the result of drug hypersensitivity reactions such as maculopapular drug rashes (MDR). The aim of this study was to investigate whether COVID-19 may impact the development of the MDR.

Methods

Blood and skin samples from COVID-19 patients (based on a positive nasopharyngeal PCR) suffering from MDR (COVID-MDR), healthy controls, non-COVID-19-related patients with drug rash with eosinophilia and systemic symptoms (DRESS), and MDR were analyzed. We utilized imaging mass cytometry (IMC) to characterize the cellular infiltrate in skin biopsies. Furthermore, RNA sequencing transcriptome of skin biopsy samples and high-throughput multiplexed proteomic profiling of serum were performed.

Results

IMC revealed by clustering analyses a more prominent, phenotypically shifted cytotoxic CD8⁺ T cell population and highly activated monocyte/macrophage (Mo/Mac) clusters in COVID-MDR. The RNA sequencing transcriptome demonstrated a more robust cytotoxic response in COVID-MDR skin. However, severe acute respiratory syndrome coronavirus 2 was not detected in skin biopsies at the time point of MDR diagnosis. Serum proteomic profiling of COVID-MDR patients revealed upregulation of various inflammatory mediators (IL-4, IL-5, IL-6, TNF, and IFN-γ), eosinophil and Mo/Mac -attracting chemokines (MCP-2, MCP-3, MCP-4 and CCL11). Proteomics analyses demonstrated a massive systemic cytokine storm in COVID-MDR compared with the relatively milder cytokine storm observed in DRESS, while MDR did not exhibit such features.

Conclusion

A systemic cytokine storm may promote activation of Mo/Mac and cytotoxic CD8⁺ T cells in severe COVID-19 patients, which in turn may impact the development of MDR.

Tumor lymphangiogenesis is accompanied by a higher incidence of sentinel lymph node metastasis and shorter overall survival in several types of cancer. We asked whether tumor lymphangiogenesis might also occur in distant organs with established metastases and whether it might promote further metastatic spread of those metastases to other organs. Using mouse metastasis models, we found that lymphangiogenesis occurred in distant lung metastases and that some metastatic tumor cells were located in lymphatic vessels and draining lymph nodes. In metastasis-bearing lungs of melanoma patients, a higher lymphatic density within and around metastases and lymphatic invasion correlated with poor outcome. Using a transgenic mouse model with inducible expression of vascular endothelial growth factor C (VEGF-C) in the lung, we found greater growth of lung metastases, with more abundant dissemination to other organs. Our findings reveal unexpected contributions of lymphatics in distant organs to the promotion of growth of metastases and their further spread to other organs, with potential clinical implications for adjuvant therapies in patients with metastatic cancer.

Background

Anti-PD-1 therapy has shown significant clinical activity in advanced melanoma. We developed and validated a clinical prediction scale for response to anti- PD-1 monotherapy.

Methods

A total of 315 patients with advanced melanoma treated with pembrolizumab (2 or 10 mg kg^-1 Q2W or Q3W) or nivolumab (3 mg kg^-1 Q2W) at four cancer centres between 2011 to 2013 served as the setting for the present cohort study. Variables with significant association to response on a univariate analysis were entered into a forward stepwise logistic regression model and were given a score based on ORs to calculate a clinical prediction scale.

Results

The developed clinical prediction scale included elevated LDH (1 point), age <65 years (1 point), female sex (1 point), history of ipilimumab treatment (2 points) and the presence of liver metastasis (2 points). The scale had an area under the receiver-operating curve (AUC) of 0.73 (95% CI 0.67, 0.80) in predicting response to therapy. The predictive performance of the score was maintained in the validation cohort (AUC 0.70 (95% CI 0.58, 0.81)) and the goodness-to-fit model demonstrated good calibration.

Conclusions

Based on a large cohort of patients, we developed and validated a simple five-factor prediction scale for the clinical activity of PD-1 antibodies in advanced melanoma patients. This scale can be used to stratify patients participating in clinical trials.

Acral melanoma is an aggressive type of melanoma with unknown origins. It is the most common type of melanoma in individuals with dark skin and is notoriously challenging to treat. We examine exome sequencing data of 139 tissue samples, spanning different progression stages, from 37 patients. We find that 78.4% of the melanomas display clustered copy number transitions with focal amplifications, recurring predominantly on chromosomes 5, 11, 12, and 22. These complex genomic aberrations are typically shared across all progression stages of individual patients. TERT activating alterations also arise early, whereas MAP-kinase pathway mutations appear later, an inverted order compared to the canonical evolution. The punctuated formation of complex aberrations and early TERT activation suggest a unique mutational mechanism that initiates acral melanoma. The marked intratumoral heterogeneity, especially concerning MAP-kinase pathway mutations, may partly explain the limited success of therapies for this melanoma subtype.

Plasticity of the cell state has been proposed to drive resistance to multiple classes of cancer therapies, thereby limiting their effectiveness. A high-mesenchymal cell state observed in human tumours and cancer cell lines has been associated with resistance to multiple treatment modalities across diverse cancer lineages, but the mechanistic underpinning for this state has remained incompletely understood. Here we molecularly characterize this therapy-resistant high-mesenchymal cell state in human cancer cell lines and organoids and show that it depends on a druggable lipid-peroxidase pathway that protects against ferroptosis, a non-apoptotic form of cell death induced by the build-up of toxic lipid peroxides. We show that this cell state is characterized by activity of enzymes that promote the synthesis of polyunsaturated lipids. These lipids are the substrates for lipid peroxidation by lipoxygenase enzymes. This lipid metabolism creates a dependency on pathways converging on the phospholipid glutathione peroxidase (GPX4), a selenocysteine-containing enzyme that dissipates lipid peroxides and thereby prevents the iron-mediated reactions of peroxides that induce ferroptotic cell death. Dependency on GPX4 was found to exist across diverse therapy-resistant states characterized by high expression of ZEB1, including epithelial-mesenchymal transition in epithelial-derived carcinomas, TGFβ-mediated therapy-resistance in melanoma, treatment-induced neuroendocrine transdifferentiation in prostate cancer, and sarcomas, which are fixed in a mesenchymal state owing to their cells of origin. We identify vulnerability to ferroptic cell death induced by inhibition of a lipid peroxidase pathway as a feature of therapy-resistant cancer cells across diverse mesenchymal cell-state contexts.

Knowledge of key drivers and therapeutic targets in mucosal melanoma is limited due to the paucity of comprehensive mutation data on this rare tumor type. To better understand the genomic landscape of mucosal melanoma, here we describe whole genome sequencing analysis of 67 tumors and validation of driver gene mutations by exome sequencing of 45 tumors. Tumors have a low point mutation burden and high numbers of structural variants, including recurrent structural rearrangements targeting TERT, CDK4 and MDM2. Significantly mutated genes are NRAS, BRAF, NF1, KIT, SF3B1, TP53, SPRED1, ATRX, HLA-A and CHD8. SF3B1 mutations occur more commonly in female genital and anorectal melanomas and CTNNB1 mutations implicate a role for WNT signaling defects in the genesis of some mucosal melanomas. TERT aberrations and ATRX mutations are associated with alterations in telomere length. Mutation profiles of the majority of mucosal melanomas suggest potential susceptibility to CDK4/6 and/or MEK inhibitors.

Accumulating evidence points to an important role for the gut microbiome in anti-tumor immunity. Here, we show that altered intestinal microbiota contributes to anti-tumor immunity, limiting tumor expansion. Mice lacking the ubiquitin ligase RNF5 exhibit attenuated activation of the unfolded protein response (UPR) components, which coincides with increased expression of inflammasome components, recruitment and activation of dendritic cells and reduced expression of antimicrobial peptides in intestinal epithelial cells. Reduced UPR expression is also seen in murine and human melanoma tumor specimens that responded to immune checkpoint therapy. Co-housing of Rnf5^-/- and WT mice abolishes the anti-tumor immunity and tumor inhibition phenotype, whereas transfer of 11 bacterial strains, including B. rodentium, enriched in Rnf5^-/- mice, establishes anti-tumor immunity and restricts melanoma growth in germ-free WT mice. Altered UPR signaling, exemplified in Rnf5^-/- mice, coincides with altered gut microbiota composition and anti-tumor immunity to control melanoma growth.