Jordan M. Meyers

To define the cellular composition and architecture of cutaneous squamous cell carcinoma (cSCC), we combined single-cell RNA sequencing with spatial transcriptomics and multiplexed ion beam imaging from a series of human cSCCs and matched normal skin. cSCC exhibited four tumor subpopulations, three recapitulating normal epidermal states, and a tumor-specific keratinocyte (TSK) population unique to cancer, which localized to a fibrovascular niche. Integration of single-cell and spatial data mapped ligand-receptor networks to specific cell types, revealing TSK cells as a hub for intercellular communication. Multiple features of potential immunosuppression were observed, including T regulatory cell (Treg) co-localization with CD8 T cells in compartmentalized tumor stroma. Finally, single-cell characterization of human tumor xenografts and in vivo CRISPR screens identified essential roles for specific tumor subpopulation-enriched gene networks in tumorigenesis. These data define cSCC tumor and stromal cell subpopulations, the spatial niches where they interact, and the communicating gene networks that they engage in cancer.

(Cell 182, 497–514.e1–e22; July 23, 2020) As a result of human error, the spatial feature plot labeled ITGB1 in Figure 6G was instead a duplicate of the ITGA3 data just below it. Additionally, in Figure S4C, the order of some of the bar labels on the plot were swapped, in particular, the order of Treg, CD4+ Naïve, NK, and CD8+ Naive. Both figures have been corrected online. We are confident that these inadvertent panel duplication and labeling errors did not have any effect on our analyses or on any conclusions drawn from the paper, and we apologize for the errors.Figure 6GCellular Crosstalk Landscape Associated with Leading Edge Niches (original)View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure S4CT Cell Subset Characterization and Spatial Positioning (corrected)View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure S4CT Cell Subset Characterization and Spatial Positioning (original)View Large Image Figure ViewerDownload Hi-res image Download (PPT) Multimodal Analysis of Composition and Spatial Architecture in Human Squamous Cell CarcinomaJi et al.CellJune 23, 2020In BriefIntegration of high-dimensional multi-omics approaches to characterize human cutaneous squamous cell carcinoma identifies a tumor-specific keratinocyte population as well as the immune infiltrates and heterogeneity at tumor leading edges. Full-Text PDF Open Access

Cutaneous β-human papillomavirus (β-HPV) E6 proteins inhibit NOTCH signaling by associating with the transcriptional coactivator MAML1. NOTCH has tumor suppressor activities in epithelial cells and is activated during keratinocyte differentiation. Here we report that HPV type 8 (HPV8) E6 subverts NOTCH activation during keratinocyte differentiation by inhibiting RBPJ/MAML1 transcriptional activator complexes at NOTCH target DNA. NOTCH inhibition impairs epithelial differentiation and may thus contribute to β-HPV replication and viral oncogenesis.

Cutaneous beta-papillomaviruses are associated with non-melanoma skin cancers that arise in patients who suffer from a rare genetic disorder, Epidermodysplasia verruciformis (EV) or after immunosuppression following organ transplantation. Recent studies have shown that the E6 proteins of the cancer associated beta human papillomavirus (HPV) 5 and HPV8 inhibit NOTCH and TGF-β signaling. However, it is unclear whether disruption of these pathways may contribute to cutaneous HPV pathogenesis and carcinogenesis. A recently identified papillomavirus, MmuPV1, infects laboratory mouse strains and causes cutaneous skin warts that can progress to squamous cell carcinoma. To determine whether MmuPV1 may be an appropriate model to mechanistically dissect the molecular contributions of cutaneous HPV infections to skin carcinogenesis, we investigated whether MmuPV1 E6 shares biological and biochemical activities with HPV8 E6. We report that the HPV8 and MmuPV1 E6 proteins share the ability to bind to the MAML1 and SMAD2/SMAD3 transcriptional cofactors of NOTCH and TGF-beta signaling, respectively. Moreover, we demonstrate that these cutaneous papillomavirus E6 proteins inhibit these two tumor suppressor pathways and that this ability is linked to delayed differentiation and sustained proliferation of differentiating keratinocytes. Furthermore, we demonstrate that the ability of MmuPV1 E6 to bind MAML1 is necessary for papilloma formation in experimentally infected mice. Our results, therefore, suggest that experimental MmuPV1 infection in mice will be a robust and useful experimental system to model key aspects of cutaneous HPV infection, pathogenesis and carcinogenesis.