Solar Urticaria: An Ambispective Study in a Long-term Follow-up Cohort with Emphasis on Therapeutic Predictors and Outcomes

Solar urticaria is a rare photodermatosis with several unknown pathogenic, clinical and therapeutic aspects. This study analysed the clinical and therapeutic features of a long-term follow-up solar urticaria cohort, with a focus on omalizumab management and outcomes, and characterized omalizumab response with the use of the high-affinity immunoglobulin E (IgE) receptor (FcεRI) and the Urticaria Control Test. An observational, unicentric, ambispective study was conducted from 2007 to 2023. Solar urticaria was diagnosed in 41 patients with a median follow-up of 60 months. Thirteen patients were prescribed omalizumab, with a median treatment time of 48 months. A significant decrease in FcεRI baseline levels and subsequent median increase in Urticaria Control Test was evidenced after omalizumab prescription in all patients. Drug survival at 48 months was at 88.9%. Omalizumab stepping-down protocol led to sustained omalizumab discontinuation in only 1 patient. Median basal Urticaria Control Test was lower (p < 0.01) in patients who were prescribed omalizumab and in patients without remission. This study contributes to our knowledge of omalizumab outcomes in real-life clinical practice and highlights the pathogenic importance of IgE-mediated pathways in solar urticaria, where FcεRI emerges as a possible biomarker of omalizumab response.

Noncanonical Wnt signaling promotes colon tumor growth, chemoresistance and tumor fibroblast activation

Colon tumors of the mesenchymal subtype have the lowest overall survival. Snail1 is essential for the acquisition of this phenotype, characterized by increased tumor stemness and invasion, and high resistance to chemotherapy. Here, we find that Snail1 expression in colon tumor cells is dependent on an autocrine noncanonical Wnt pathway. Accordingly, depletion of Ror2, the co-receptor for noncanonical Wnts such as Wnt5a, potently decreases Snail1 expression. Wnt5a, Ror2, and Snail1 participate in a self-stimulatory feedback loop since Wnt5a increases its own synthesis in a Ror2- and Snail1-dependent fashion. This Wnt5a/Ror2/Snail1 axis controls tumor invasion, chemoresistance, and formation of tumor spheres. It also stimulates TGFβ synthesis; consequently, tumor cells expressing Snail1 are more efficient in activating cancer-associated fibroblasts than the corresponding controls. Ror2 downmodulation or inhibition of the Wnt5a pathway decreases Snail1 expression in primary colon tumor cells and their ability to form tumors and liver metastases. Finally, the expression of SNAI1, ROR2, and WNT5A correlates in human colon and other tumors. These results identify inhibition of the noncanonical Wnt pathway as a putative colon tumor therapy.

Loss of dyskerin facilitates the acquisition of metastatic traits by altering the mevalonate pathway

The initial dissemination of cancer cells from many primary tumors implies intravasation to lymphatic nodes or blood vessels. To investigate the mechanisms involved, we analyzed the expression of small non-coding RNAs in cutaneous squamous cell carcinoma (cSCC), a prevalent tumor that mainly spreads to lymph nodes. We report the reduced expression of small nucleolar RNAs in primary cSCCs that metastasized when compared to non-metastasizing cSCCs, and the progressive loss of DKC1 (dyskerin, which stabilizes the small nucleolar RNAs) along the metastasis. DKC1 depletion in cSCC cells triggered lipid metabolism by altering the mevalonate pathway and the acquisition of metastatic traits. Treatment of DKC1-depleted cells with simvastatin, an inhibitor of the mevalonate pathway, blocked the expression of proteins involved in the epithelial-to-mesenchymal transition. Consistently, the expression of the enzyme 3-hydroxy-3-methylglutaryl-CoA synthase 1 was associated with pathological features of high metastatic risk in cSCC patients. Our data underpin the relevance of the mevalonate metabolism in metastatic dissemination and pave the possible incorporation of therapeutic approaches among the antineoplastic drugs used in routine patient care.

Remibrutinib inhibits hives effector cells stimulated by serum from chronic urticaria patients independently of FcεR1 expression level and omalizumab clinical response

BACKGROUND

Despite advances in the treatment of chronic urticaria, in a significant percentage of the patients symptoms are not fully controlled with conventional approaches. New strategies under development include blocking intracellular mediators of mast cell and basophil activation.

OBJECTIVE

We aim to investigate the effects of the Bruton's tyrosine kinase (BTK) inhibitor remibrutinib on human blood basophils and CD34+ -derived mast cells activation induced by serum obtained from chronic urticaria patients.

METHODS

Twenty-two patients with chronic spontaneous urticaria (mean age 52 years, 27% women) and 22 patients with chronic inducible urticaria (46 years, 27% women) were included in the study together with a sex-matched control group. Patients were classified as responders or non-responders to anti-IgE therapy on the basis of their clinical data, FcεR1a expression on blood basophils and total IgE levels. Changes on CD63 expression-as an activation marker-, were used to evaluate in vitro the response of basophils and mast cells to serum exposure and the inhibitory effects of remibrutinib.

RESULTS

Remibrutinib inhibits degranulation induced by IgE cross-linking in mast cells and basophils and also the activation triggered by factors present in the sera of spontaneous and inducible chronic urticaria patients. Patient's serum induces a greater degranulation of effector cells than controls. Activation of mast cells and basophils by patient sera and remibrutinib effects were not related to omalizumab responsiveness.

CONCLUSION

Remibrutinib inhibits activation of human basophils and mast cells induced in vitro by exposure to the serum of chronic urticaria patients independently of their response to omalizumab.

New transcriptome and clinical findings of platelet-activating factor in chronic spontaneous urticaria: Pathogenic and treatment relevance

The objective of the study was to assess the pathogenic and treatment relevance of Platelet Activating factor (PAF) in chronic spontaneous urticaria (CSU). The expression and cellular location of PAF receptor (PAFR) and serum levels of PAF and PAF acetylhydrolase (PAF-AH) in patients with moderate/severe CSU (n = 45) and healthy controls (HCs, n = 17) were studied. Skin samples from the active wheal (LS-CSU, 13 samples for qPCR and 33 for immunohistochemistry) and non-lesional skin (NLS-CSU, 13 samples) of CSU patients and HCs (13 samples and 5 for immunohistochemistry) were analyzed. Serum PAF and PAF-AH levels were measured by ELISA and compared between HC (10 samples) and CSU patients (25 samples) and, among them, between those refractory and non-refractory to second-generation H₁ -antihistamines (sgAH). PAFR mRNA expression was significantly higher in LS-CSU versus HCs (p = 0.014). PAFR positive staining in immunohistochemistry was mainly found in the epidermal basal layer in HCs, whereas it was broadly present along the epidermis in LS-CSU samples. Endothelial cells showed PAFR expression exclusively in LS-CSU and NLS-CSU samples. PAFR expression was observed in the nerves of HC, LS-CSU, and NLS-CSU samples. Double PAFR/CD43 expression showed that T-lymphocytes were the main cell type from the wheal inflammatory infiltrate expressing PAFR. A significantly lower PAF-AH/PAF ratio was observed in sgAH non-responders versus responders (6.1 vs. 12.6; p = 0.049). Our study confirms that PAF is a mediator of wheal pathogenesis in CSU. The significantly lower PAF-AH/PAF ratio in sgAH non-responders vs responders suggests that PAF could be a potential biomarker of sgAH refractoriness.

Identification of differentially expressed genes in actinic keratosis samples treated with ingenol mebutate gel

Actinic keratosis is a common skin disease that may progress to invasive squamous cell carcinoma if left untreated. Ingenol mebutate has demonstrated efficacy in field treatment of actinic keratosis. However, molecular mechanisms on ingenol mebutate response are not yet fully understood. In this study, we evaluated the gene expression profiles of actinic keratosis lesions before and after treatment with ingenol mebutate using microarray technology. Actinic keratoses on face/scalp of 15 immunocompetent patients were identified and evaluated after treatment with topical ingenol mebutate gel 0.015%, applied once daily for 3 consecutive days. Diagnostic and clearance of lesions was determined by clinical, dermoscopic, and reflectance confocal microscopy criteria. Lesional and non-lesional skin biopsies were subjected to gene expression analysis profiled by Affymetrix microarray. Differentially expressed genes were identified, and enrichment analyses were performed using STRING database. At 8 weeks post-treatment, 60% of patients responded to ingenol mebutate therapy, achieving complete clearance in 40% of cases. A total of 128 differentially expressed genes were identified following treatment, and downregulated genes (114 of 128) revealed changes in pathways important to epidermal development, keratinocyte differentiation and cornification. In responder patients, 388 downregulated genes (of 450 differentially expressed genes) were also involved in development/differentiation of the epidermis, and immune system-related pathways, such as cytokine and interleukin signaling. Cluster analysis revealed two relevant clusters showing upregulated profile patterns in pre-treatment actinic keratoses of responders, as compared to non-responders. Again, differentially expressed genes were mainly associated with cornification, keratinization and keratinocyte differentiation. Overall, the present study provides insight into the gene expression profile of actinic keratoses after treatment with ingenol mebutate, as well as identification of genetic signatures that could predict treatment response.

Molecular characterisation of oncogenic urothelial mosaic mutations in patients with extensive keratinocytic epidermal naevi

Background: Keratinocytic epidermal naevi (KENs) are congenital benign skin mosaic lesions that share common mutations with some subsets of urothelial carcinomas. Moreover, several patients with extensive KEN who also developed urothelial carcinomas at young ages have been reported. Thus, patients with extensive KEN may harbour mosaic urothelial oncogenic mutations that would favour the early development of urothelial carcinomas. Methods: We selected five patients with extensive KEN involving the lower part of the back and performed a molecular characterisation of urothelial and cutaneous samples using a next-generation sequencing (NGS) custom panel targeting candidate oncogenic genes. Results: Mosaic pathogenic mutations were detected in KEN in all patients. In four out of five patients, mosaic pathogenic mutations in FGFR2 or HRAS were also detected in samples from the urothelial tract. Moreover, we report a patient who developed urothelial carcinomas at age 29 and harboured an HRAS G12S mutation both in skin and urothelial tumour samples. Conclusions: We conclude that patients with extensive KEN involving the lower part of the back frequently harbour oncogenic mutations in the urothelium that may induce the development of carcinomas. NGS panels can be considered as highly sensitive tools to identify this subgroup of patients, which might permit adoption of screening measures to detect malignant transformation at early stages.

A Myxoid Fibrotic Reaction Pattern is Associated with Metastatic Risk in Cutaneous Squamous Cell Carcinoma

Although desmoplasia has been associated with poor prognoses in cutaneous squamous cell carcinoma, little attention has been paid to the patterns of fibrosis. This study aimed to examine the different stromal fibrotic patterns as markers of metastatic risk. We performed a multicenter retrospective study that included 102 cutaneous squamous cell carcinomas (52 non-metastatic and 50 metastatic carcinomas). Clinical and histopathological data were registered. The fibrotic reaction pattern was classified as mature, intermediate or immature depending on the presence of keloid-like collagen and myxoid stroma. The immature pattern (areas characterized by myxoid changes with no inflammation) was observed in 18 samples and its presence was significantly associated with immunosuppression, budding, desmoplasia, perineural invasion, anatomic level, tumoural depth and metastatic risk in the multivariate analysis. Our findings suggest that the presence of an immature myxoid fibrotic pattern, which can be easily identified by routine hematoxylin-eosin staining, is strongly associated with metastatic risk.

The Polycomb proteins RING1B and EZH2 repress the tumoral pro-inflammatory function in metastasizing primary cutaneous squamous cell carcinoma

Cutaneous squamous cell carcinoma (cSCC) is the second most common malignancy in humans and approximately 5% metastasize, usually to regional lymph nodes. Epigenetic regulation of gene expression may allow tumoral cells to acquire new functions in order to escape from the primary tumor. The aim of this study was to investigate the expression and function of proteins of the Polycomb family of epigenetic regulators in the metastatic process of cSCC. A higher expression of RING1B and EZH2 was detected by immunohistochemistry in a series of primary cSCC tumors that metastasized (MSCCs) when compared with non-metastasizing cSCCs (non-MSCCs). Stable downregulation of RING1B and EZH2 in cSCC cells results in enhanced expression of inflammatory cytokines and activation of the NF-κB signaling pathway. Accordingly, non-MSCCs display higher levels of membranous pS176-inhibitor of NF-kB kinase, and their stroma is enriched in neutrophils and eosinophils when compared with MSCCs. In vitro, hematopoietic cells exhibit a substantial migratory response to supernatants from Polycomb-depleted cSCC cells. Altogether, these data indicate that RING1B and EZH2 repress the innate inflammatory cSCC function and impair tumor immunosurveillance and suggest that patients with high-risk cSCCs could benefit from clinical therapies addressed to harness the immune response.

MiR-204 silencing in intraepithelial to invasive cutaneous squamous cell carcinoma progression

Background

Cutaneous squamous cell carcinoma (cSCC) is the second most common skin cancer and frequently progresses from an actinic keratosis (AK), a sun-induced keratinocyte intraepithelial neoplasia (KIN). Epigenetic mechanisms involved in the phenomenon of progression from AK to cSCC remain to be elicited.

Methods

Expression of microRNAs in sun-exposed skin, AK and cSCC was analysed by Agilent microarrays. DNA methylation of miR-204 promoter was determined by bisulphite treatment and pyrosequencing. Identification of miR-204 targets and pathways was accomplished in HaCat cells. Immunofluorescence and immunohistochemistry were used to analyze STAT3 activation and PTPN11 expression in human biopsies.

Results

cSCCs display a marked downregulation of miR-204 expression when compared to AK. DNA methylation of miR-204 promoter was identified as one of the repressive mechanisms that accounts for miR-204 silencing in cSCC. In HaCaT cells miR-204 inhibits STAT3 and favours the MAPK signaling pathway, likely acting through PTPN11, a nuclear tyrosine phosphatase that is a direct miR-204 target. In non-peritumoral AK lesions, activated STAT3, as detected by pY705-STAT3 immunofluorescence, is retained in the membrane and cytoplasm compartments, whereas AK lesions adjacent to cSCCs display activated STAT3 in the nuclei.

Conclusions

Our data suggest that miR-204 may act as a “rheostat” that controls the signalling towards the MAPK pathway or the STAT3 pathway in the progression from AK to cSCC.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-016-0537-z) contains supplementary material, which is available to authorized users.