Human Basal Cell Carcinoma Research Articles

Evidence of Neutrophils and Neutrophil Extracellular Traps in Human NMSC with Regard to Clinical Risk Factors, Ulceration and CD8+ T Cell Infiltrate.

Non-melanoma skin cancers (NMSC), including basal cell carcinoma (BCC), cutaneous squamous cell carcinoma (cSCC), and Merkel cell carcinoma (MCC), are increasingly common and present significant healthcare challenges. Neutrophil extracellular traps (NETs), chromatin fibers expulsed by neutrophil granulocytes, can promote immunotherapy resistance via an impairment of CD8+ T cell-mediated cytotoxicity. Here, to identify a potential therapeutic target, we investigate the expulsion of NETs and their relation to CD8+ T cell infiltration in NMSC. Immunofluorescence staining for neutrophils (CD15) and NETs (H3cit), as well as immunohistochemistry for cytotoxic T cells (CD8+) on human cSCCs (n = 24), BCCs (n = 17) and MCCs (n = 12), revealed a correlation between neutrophil infiltration and ulceration diameter in BCC and MCC, but not in cSCC. In BCC and cSCC, neutrophil infiltration also correlated with the cross-sectional area (CSA). NETs were not associated with established risk factors but with the presence of an ulceration, and, in cSCC, with abscess-like structures. CD8+ T cell infiltration was not reduced in tumors that were NET-positive nor in those with a denser neutrophil infiltration. This study is the first to report and characterize NETs in NMSC. Thus, it gives an incentive for further research in this relevant yet understudied topic.

200 (PB188): Cornulin, detected through electroporation based molecular sampling, discriminates between human basal cell carcinoma and squamous cell carcinoma

200 (PB188): Cornulin, detected through electroporation based molecular sampling, discriminates between human basal cell carcinoma and squamous cell carcinoma

Micro RNA Dysregulation in Keratinocyte Carcinomas: Clinical Evidence, Functional Impact, and Future Directions.

The keratinocyte carcinomas, basal cell carcinoma (BCC), and cutaneous squamous cell carcinoma (cSCC), are the most common cancers in humans. Recently, an increasing body of literature has investigated the role of miRNAs in keratinocyte carcinoma pathogenesis, progression and their use as therapeutic agents and targets, or biomarkers. However, there is very little consistency in the literature regarding the identity of and/or role of individual miRNAs in cSCC (and to a lesser extent BCC) biology. miRNA analyses that combine clinical evidence with experimental elucidation of targets and functional impact provide far more compelling evidence than studies purely based on clinical findings or bioinformatic analyses. In this study, we review the clinical evidence associated with miRNA dysregulation in KCs, assessing the quality of validation evidence provided, identify gaps, and provide recommendations for future studies based on relevant studies that investigated miRNA levels in human cSCC and BCC. Furthermore, we demonstrate how miRNAs contribute to the regulation of a diverse network of cellular functions, and that large-scale changes in tumor cell biology can be attributed to miRNA dysregulation. We highlight the need for further studies investigating the role of miRNAs as communicators between different cell types in the tumor microenvironment. Finally, we explore the clinical benefits of miRNAs as biomarkers of keratinocyte carcinoma prognosis and treatment.

Plasmonic nanophotothermal therapy: Destruction of 500 mm3 subcutaneous human basal cell carcinoma with gold nanoparticles and near infrared laser.

Multilesional basal cell carcinoma (BCC) are spread on sun exposed skin areas, including arms, face and back. The first-line treatment remains the surgical resection or Mohs surgery. Despite its high complexity, Mohs surgery is well practiced in USA and Germany and presents very good results both in esthetic and in carcinology point of view. Large lesions more than 2cm remain challenging to remove by topical cream used in photodynamic therapy (PDT). If these larger lesions are not treated in less than 1 month, they could grow deeply in the skin, thus enhancing the risk of reoccurrence and the severity of the disease. Despite this model herein studied, that is non melanoma skin cancer is a good prognostic cancer, the therapy aims to be applied to more aggressive melanoma skin cancers. Total regression of large cutaneous lesions less than 1 month with no reoccurrence. Tumor induction on murine model bearing a 500 mm3 subcutaneous lesion. Increasing dose of gold nanoparticles at fixed initial concentration C0=0.3mg/mL, infused into the tumor then exposition of the region of interest to NIR medical laser to assess the therapy. One or two intratumoral administration(s) were compared to surgery and control, that is no treatment, laser alone or nanoparticles alone. Gold nanoparticles alone or the NIR laser alone did not induce the tumor regression. The combination of laser and nanoparticles called plasmonic nanophotothermal therapy induced apoptosis. Derma and hypoderm do not show any visible gold nanoparticles and demonstrated a good cicatrization process. Plasmonic nanophotothermal therapy using two doses of gold nanoparticles was the only protocol that proved its efficacy on large lesions in 14 days, that is 500 mm3 on a murine model bearing human basal cell carcinoma.

Assessment of Mammalian Target of Rapamycin Pathway Activation in Basal Cell Carcinoma as a New Therapeutic Approach.

Targeting the mammalian target of rapamycin (mTOR) pathway represents a potentially novel approach to treat basal cell carcinoma (BCC), but activation of this pathway has not been well described in human BCCs. The purpose of this study was to assess whether mTOR pathway activation occurs in BCCs (both sporadic and syndromic) and report a case of a patient with Gorlin syndrome (GS) whose clinically suspicious BCCs responded to mTOR inhibition through topical sirolimus treatment. After Stanford Institutional Review Board Approval, archived BCCs from patients with GS (n = 25), sporadic BCCs (n = 35), and control tissues were subjected to immunohistochemical analysis for the activation of mTOR pathway, and immunohistochemical staining intensity was evaluated by a dermatopathologist. BCCs (compared with normal skin) had elevated levels of eIF4EBP1 ( Padjusted = 0.0336), which is downstream of mTOR. a serine/threonine kinase Phospho-(AKT), which interacts with mTOR, was also significantly elevated (perinuclear: Padjusted < 0.0001; cytoplasmic: Padjusted = 0.0021). When off-label topical 1% sirolimus was used on a pediatric patient with GS, we noted reduction of new BCC development and decreased size of existing neoplasms clinically suspicious for BCCs. This treatment was well tolerated after 2 years of continuous use, with no other treatments needed during this period. Topical sirolimus is a promising therapeutic candidate against both sporadic and GS-associated BCC. Multicenter, prospective studies are needed to understand the efficacy and safety of topical mTOR inhibitors in BCC treatment, and ascertain whether the immunohistochemical markers downstream of mTOR could have predictive value in identifying BCCs most likely to respond to topical mTOR inhibitors, such as sirolimus.

Laser-assisted topical delivery of vismodegib reduces hedgehog gene expression in human basal cell carcinomas in vivo.

Systemically delivered hedgehog inhibitors including vismodegib and sonidegib are widely used to treat basal cell carcinomas (BCCs). Ablative fractional laser (AFL)-assisted topical delivery of vismodegib has been demonstrated in preclinical studies. The aim of this explorative clinical study was to evaluate intratumoral vismodegib concentrations and effect on hedgehog pathway gene expression following AFL-assisted topical vismodegib delivery to BCCs. In an open-label clinical trial, 16 nodular BCCs (in n = 9 patients) received one application of CO2 -AFL (40 mJ/microbeam, 10% density) followed by topical vismodegib emulsion. After 3-4 days, vismodegib concentrations in tumor biopsies (n = 15) and plasma were analyzed and compared with samples from patients receiving oral treatment (n = 3). GLI1, GLI2, PTCH1, and PTCH2 expression was determined by quantitative polymerase chain reaction (n = 7) and GLI1 additionally by in situ hybridization (n = 3). Following AFL-assisted topical administration, vismodegib was detected in 14/15 BCCs and reached a median concentration of 6.2 µmol/L, which compared to concentrations in BCC tissue from patients receiving oral vismodegib (9.5 µmol/L, n = 3, p = 0.8588). Topical vismodegib reduced intratumoral GLI1 expression by 51%, GLI2 by 55%, PTCH1 and PTCH2 each by 73% (p ≤ 0.0304) regardless of vismodegib concentrations (p ≥ 0.3164). In situ hybridization demonstrated that GLI1 expression was restricted to tumor tissue and downregulated in response to vismodegib exposure. A single AFL-assisted topical application of vismodegib resulted in clinically relevant intratumoral drug concentrations and significant reductions in hedgehog pathway gene expressions.

Multiscale spatial mapping of cell populations across anatomical sites in healthy human skin and basal cell carcinoma.

Our understanding of how human skin cells differ according to anatomical site and tumour formation is limited. To address this, we have created a multiscale spatial atlas of healthy skin and basal cell carcinoma (BCC), incorporating in vivo optical coherence tomography, single-cell RNA sequencing, spatial global transcriptional profiling, and in situ sequencing. Computational spatial deconvolution and projection revealed the localisation of distinct cell populations to specific tissue contexts. Although cell populations were conserved between healthy anatomical sites and in BCC, mesenchymal cell populations including fibroblasts and pericytes retained signatures of developmental origin. Spatial profiling and in silico lineage tracing support a hair follicle origin for BCC and demonstrate that cancer-associated fibroblasts are an expansion of a POSTN+ subpopulation associated with hair follicles in healthy skin. RGS5+ pericytes are also expanded in BCC suggesting a role in vascular remodelling. We propose that the identity of mesenchymal cell populations is regulated by signals emanating from adjacent structures and that these signals are repurposed to promote the expansion of skin cancer stroma. The resource we have created is publicly available in an interactive format for the research community.

Exploring multisite heterogeneity of human basal cell carcinoma proteome and transcriptome.

Basal cell carcinoma (BCC) is the most common type of skin cancer. Due to multiple, potential underlying molecular tumor aberrations, clinical treatment protocols are not well-defined. This study presents multisite molecular heterogeneity profiles of human BCC based on RNA and proteome profiling. Three areas from lesions excised from 9 patients were analyzed. The focus was gene expression profiles based on proteome and RNA measurements of intra-tumor heterogeneity from the same patient and inter-tumor heterogeneity in nodular, infiltrative, and superficial BCC tumor subtypes from different patients. We observed significant overlap in intra- and inter-tumor variability of proteome and RNA expression profiles, showing significant multisite heterogeneity of protein expression in the BCC tumors. Inter-subtype analysis has also identified unique proteins for each BCC subtype. This profiling leads to a deeper understanding of BCC molecular heterogeneity and potentially contributes to developing new sampling tools for personalized diagnostics therapeutic approaches to BCC.

Documented and projected actions in vitro of thyroid hormone as L -thyroxine (T4) on basal cell carcinoma of the skin

Thyroid hormone as L-thyroxine (T4) at physiological concentrations acts at its cell surface receptor on integrin avb3 to stimulate cancer cell proliferation1. These proliferation studies have been conducted in vitro, but pharmacological reduction of T4 and substitution of nuclear receptor ligand 3,3’,5-triiodo-L-thyronine (T3) is a state of euthyroid hypothyroxinemia that has been shown clinically to arrest tumor growth in patients with cancer. T3 is inactive at physiological levels at the plasma membrane integrin receptor. A preclinical study of human basal cell carcinoma (BCC) cells has shown that the integrin thyroid hormone receptor regulates BCC radiosensitivity. While the large majority of BCCs are very manageable clinically, a small number of such tumors are aggressive. In this review of documented and proposed effects of T4 on BCC cells, we raise the possibility that BCC aggressiveness reflects T4 actions on its thyrointegrin target. The functions affected by T4 at the integrin in other human cancers include enhanced cell proliferation, anti-apoptosis, immune checkpoint regulation and metastasis, as well as state of radiosensitivity. The importance of investigating this possible pathophysiology is that euthyroid hypothyroxinemia may be tested as a treatment option.

Feasibility of Intratumoral Anti-PD1 as Treatment of Human Basal Cell Carcinoma: An Explorative Study with Adjuvant Ablative Fractional Laser

The use of immune checkpoint inhibitors (ICI) is expanding with the approval for advanced/metastatic keratinocyte carcinoma; however, most tumors are non-aggressive. Local administration could broaden ICI, but adequate immune response might require an immune-attractive adjuvant such as ablative fractional laser (AFL). Accordingly, this study aimed to explore intratumoral injection of anti-PD1 with and without AFL in basal cell carcinoma (BCC), exploring anti-PD1 concentration, immune cell infiltration, tumor response, and safety. This open-label, proof-of-concept trial investigated intratumoral anti-PD1 + AFL combination therapy versus anti-PD1 or AFL monotherapy in 28 BCC patients. The primary endpoints were immune cell infiltration evaluated immunohistochemically and clinical tumor response after 3 months. The secondary outcomes were tumoral drug concentration and safety. The most robust response was obtained following intervention with combined anti-PD1+AFL, leading to a ~2.5-fold increase in CD3+ cells (p = 0.027), and tumor reduction ≥25% in 73%, including two tumors with complete remission. Upon anti-PD1 monotherapy, a slight decrease in CD3+ cells was observed while a non-significant increase following AFL was seen. Tumor reduction ≥25% was seen in 45% and 50%, respectively, after anti-PD1 and AFL monotherapy. The CD8/CD3 ratio remained unchanged after anti-PD1+AFL and anti-PD1 monotherapy, while AFL led to a decreased ratio. A non-significant decline in the Foxp3/CD3 ratio was observed for all groups. Side-effects were mild with no systemic drug concentration detected. Intratumoral anti-PD1 injection is feasible, and a single exposure to locally injected anti-PD1 with adjuvant AFL increased immune cell infiltration and reduction in BCC with limited side-effects.

432 Integrated multi-omics reveals cellular and molecular interactions governing the invasive niche of basal cell carcinoma

Tumors invade the surrounding tissues to progress, but the heterogeneity of cell types at the tumor-stroma interface and the complexity of their potential interactions hampered mechanistic insight required for efficient therapeutic targeting. Here, combining single-cell and spatial transcriptomics on human basal cell carcinomas (BCCs), we define the cellular contributors of tumor progression. In the invasive niche, tumor cells exhibit a collective migration phenotype, characterized by the expression of cell-cell junction complexes.

468 Preferentially Expressed Antigen in Melanoma Modulates Sensitivity to Retinoic Acid and Cell Cycle Control in Immortalized and Malignant Keratinocytes

Retinoids can be used to treat and prevent the formation of basal cell carcinoma (BCC) and squamous cell carcinomas (SCCs; notably cutaneous and oral SCC). Preferentially Expressed Antigen in Melanoma (PRAME), a gamete-specific repressor of retinoid-induced differentiation, is ectopically expressed in BCC and SCC tumors. However, the effects of PRAME on the development of these cancers and their sensitivity to retinoid therapies are unknown. The purpose of this study was to investigate PRAME’s influence on retinoid response and proliferation in benign human keratinocytes, BCC and SCC cells.

Integrated multi-omics reveals cellular and molecular interactions governing the invasive niche of basal cell carcinoma

Tumors invade the surrounding tissues to progress, but the heterogeneity of cell types at the tumor-stroma interface and the complexity of their potential interactions hampered mechanistic insight required for efficient therapeutic targeting. Here, combining single-cell and spatial transcriptomics on human basal cell carcinomas, we define the cellular contributors of tumor progression. In the invasive niche, tumor cells exhibit a collective migration phenotype, characterized by the expression of cell-cell junction complexes. In physical proximity, we identify cancer-associated fibroblasts with extracellular matrix-remodeling features. Tumor cells strongly express the cytokine Activin A, and increased Activin A-induced gene signature is found in adjacent cancer-associated fibroblast subpopulations. Altogether, our data identify the cell populations and their transcriptional reprogramming contributing to the spatial organization of the basal cell carcinoma invasive niche. They also demonstrate the power of integrated spatial and single-cell multi-omics to decipher cancer-specific invasive properties and develop targeted therapies.

077 Identifying genetic factors that enable basal cell carcinoma to transition from microscopic to macroscopic disease

Basal cell carcinoma (BCC) is driven by constitutive activation of the Hedgehog (Hh) signaling pathway, most commonly through loss-of-function mutations in PTCH1. Using animal models, we demonstrate here that microscopic BCC-like tumors initiated by loss of Ptch1 or gain of Smo fail to progress and eventually enter into a dormant state. Because loss-of-function mutations in NOTCH1/2 and TRP53 are commonly detected in human BCC, we sought to determine if these genetic factors modulate tumor progression.

847 Modeling basal cell carcinoma in 3D organotypic raft cultures

Basal cell carcinoma (BCC) is the most-commonly diagnosed cancer worldwide with limited availability for non-surgical treatments. The Hedgehog signaling cascade drives tumorigenesis, but efforts to develop effective chemotherapeutics have been thwarted by chemoresistant tumor recurrence. A contributing factor to this is an overall lack of human-based preclinical models. We endeavored to develop 3D organotypic raft models that mimic characteristics of human BCC by combining primary normal human epidermal keratinocytes (NHEK) with established murine BCC cells.

115 The impact of aging on murine basal cell carcinoma development

Basal cell carcinoma (BCC) is the most common skin malignancy and most frequently occurs in patients over 70 years of age. Dysregulated Hedgehog (Hh) signaling and consequent activation of GLI transcription factors is a molecular hallmark of human BCC and drives BCC-like tumor development in genetically engineered mice, which are typically studied at a young age. We examined the impact of aging on BCC tumorigenesis in young versus aged cohorts of Lgr6-CreER;R26-LSL-rtTA;tetO-GLI2A mice, in which topical 4-OHT treatment activates Cre function and rtTA expression in Lgr6+ cells and their progeny, and treatment with doxycycline leads to expression of a tetO-driven activator form of GLI2.

083 Defining the immune response in basal cell carcinoma spontaneous regression

In the US, more people are diagnosed with basal cell carcinoma (BCC) than any other cancer, but treatment of advanced tumors is frequently complicated by drug resistance. Interestingly, 20-29% of human BCC tumors are reported to shrink spontaneously in the absence of treatment through an unknown mechanism. With case studies suggesting a role for immune activation in this tumor regression, we hypothesize that T cells are recruited to growing BCCs to promote spontaneous tumor shrinkage. The inducible Gli1CreERT2; Ptch fl/fl transgenic BCC mouse model shows microtumor growth in the skin followed by significant reduction (p<0.001) in tumor area after 10 weeks.

BG04: Exploring the cellular and genetic composition of human basal cell carcinoma at single‐cell and spatial resolutions

BG04: Exploring the cellular and genetic composition of human basal cell carcinoma at single‐cell and spatial resolutions

Single-cell analysis of human basal cell carcinoma reveals novel regulators of tumor growth and the tumor microenvironment.

How basal cell carcinoma (BCC) interacts with its tumor microenvironment to promote growth is unclear. We use singe-cell RNA sequencing to define the human BCC ecosystem and discriminate between normal and malignant epithelial cells. We identify spatial biomarkers of tumors and their surrounding stroma that reinforce the heterogeneity of each tissue type. Combining pseudotime, RNA velocity–PAGA, cellular entropy, and regulon analysis in stromal cells reveals a cancer-specific rewiring of fibroblasts, where STAT1, TGF-β, and inflammatory signals induce a noncanonical WNT5A program that maintains the stromal inflammatory state. Cell-cell communication modeling suggests that tumors respond to the sudden burst of fibroblast-specific inflammatory signaling pathways by producing heat shock proteins, whose expression we validated in situ. Last, dose-dependent treatment with an HSP70 inhibitor suppresses in vitro vismodegib-resistant BCC cell growth, Hedgehog signaling, and in vivo tumor growth in a BCC mouse model, validating HSP70’s essential role in tumor growth and reinforcing the critical nature of tumor microenvironment cross-talk in BCC progression.

Functional Disruption of Gli1-DNA Recognition via a Cobalt(III) Complex.

The aberrant activation of the Gli family of zinc finger transcription factors (ZFTFs) is associated with several types of human cancer, including medulloblastoma and basal cell carcinoma. We have reported the use of cobalt(III) Schiff-base complexes (Co(III)-sb) as potent inhibitors of ZFTFs in vivo. These complexes inhibit transcription by displacing the zinc finger domain's structural Zn(II) ion, destabilizing the alpha helix necessary for DNA recognition. Here, we describe the use of Co(III)-sb complexes for the selective inhibition of Gli1. Spectroscopic and computational studies of the Gli1 DNA binding domain found that Co(III)-sb displaced Zn(II) through direct coordination with the His residues of the Cys2 His2 Zn(II) binding site. As a result, there is a dose-dependent degradation of the alpha-helix content in the DNA binding domain of Gli1 and corresponding inhibition of consensus sequence recognition. We conclude that this strategy is well suited for the development of new and potent inhibitors of Gli1.