Molecularly matched targeted therapy: a promising approach for refractory metastatic melanoma.

BACKGROUND: Only a fraction of patients with metastatic melanoma derive durable benefit from approved treatments. The clinical impact of personalized medicine strategies for melanoma, apart from BRAF, NRAS, or CKIT targeting, has rarely been reported. MATERIALS AND METHODS: By means of the Group of Cutaneous Oncology of the French Society of Dermatology, we retrospectively included all patients with advanced melanoma aged 18 years and older for whom molecular testing identified one or more actionable molecular alterations and who accordingly received molecularly matched therapy. We excluded patients with only BRAF, NRAS, or CKIT alterations and patients who received molecularly matched therapy for less than 15 days. RESULTS: We included 26 patients with a median follow-up of 8 months (1-54), a median age of 63 years (24-89), and a sex ratio of 2.7. These patients had been heavily pretreated, and 64% had elevated LDH levels. The disease control rate was 38%, with 4 cases of partial response (overall response rate: 15%) and 6 of stable disease for at least 6 months. The median duration of treatment was 3.1 months (0.9-13.5). Among patients with disease control, the median duration of control was 6.6 months (2.6-13.5) and 3 cases were ongoing at the end of the study. Patients with controlled disease had GNA11, MAP2K1, FYCO1-RAF1, HRAS, ATM, CCND1, MDM2/CDK4, and CDKN2A/NRAS alterations. CONCLUSIONS: High-throughput sequencing followed by matched targeted therapy is a promising approach for patients with advanced melanoma refractory to approved treatments.

VEXAS syndrome is characterized by inflammasome activation and monocyte dysregulation.

Acquired mutations in the UBA1 gene were recently identified in patients with severe adult-onset auto-inflammatory syndrome called VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic). However, the precise physiological and clinical impact of these mutations remains poorly defined. Here we study a unique prospective cohort of VEXAS patients. We show that monocytes from VEXAS are quantitatively and qualitatively impaired and display features of exhaustion with aberrant expression of chemokine receptors. In peripheral blood from VEXAS patients, we identify an increase in circulating levels of many proinflammatory cytokines, including IL-1ß and IL-18 which reflect inflammasome activation and markers of myeloid cells dysregulation. Gene expression analysis of whole blood confirms these findings and also reveals a significant enrichment of TNF-α and NFκB signaling pathways that can mediate cell death and inflammation. This study suggests that the control of the nflammasome activation and inflammatory cell death could be therapeutic targets in VEXAS syndrome.

Enhanced fetal hematopoiesis in response to symptomatic SARS-CoV-2 infection during pregnancy.

BACKGROUND: Pregnant women and their fetuses are particularly susceptible to respiratory pathogens. How they respond to SARS-CoV-2 infection is still under investigation. METHODS: We studied the transcriptome and phenotype of umbilical cord blood cells in pregnant women infected or not with SARS-CoV-2. RESULTS: Here we show that symptomatic maternal COVID-19 is associated with a transcriptional erythroid cell signature as compared with asymptomatic and uninfected mothers. We observe an expansion of fetal hematopoietic multipotent progenitors skewed towards erythroid differentiation that display increased clonogenicity. There was no difference in inflammatory cytokines levels in the cord blood upon maternal SARS-CoV-2 infection. Interestingly, we show an activation of hypoxia pathway in cord blood cells from symptomatic COVID-19 mothers, suggesting that maternal hypoxia may be triggering this fetal stress hematopoiesis. CONCLUSIONS: Overall, these results show a fetal hematopoietic response to symptomatic COVID-19 in pregnant mothers in the absence of vertically transmitted SARS-CoV-2 infection which is likely to be a mechanism of fetal adaptation to the maternal infection and reduced oxygen supply.

During pregnancy, women are more prone to respiratory infectious diseases. It is not known if COVID-19 infection has an adverse effect on the growing fetus. Here, we aimed to identify any potential effects of COVID-19 infection on the fetus by taking measurements from the umbilical cord blood cells. In mothers who displayed symptomatic COVID-19 infection, we observed an increased production of hematopoietic progenitor cells, especially the ones that are responsible for producing red blood cells. We think this might be a coping mechanism for the fetus, as the mother's body deals with the infection. Therefore, our work shows that growing fetuses do respond to maternal COVID-19 symptoms, even when they are protected in the womb from the infection and may never get infected by the mother.

Diagnostic Accuracy of GATA6 Immunostaining in Sebaceous Tumors of the Skin.

The accurate diagnosis of skin adnexal neoplasms is sometimes challenging but is necessary because medical management and follow-up may differ between tumors. GATA6 transcription factor has been identified as a new marker of the upper folliculosebaceous compartment (lower infundibulum, junctional zone and isthmus, and upper sebaceous gland) in the human skin. We aimed to determine the diagnostic accuracy of GATA6 immunostaining to diagnose sebaceous tumors compared with that to diagnose other adnexal and nonadnexal cutaneous neoplasms. We conducted a retrospective, evaluator-nonblinded study comparing the reference standard (diagnosis by an expert dermatopathologist) with GATA6 immunostaining to identify sebaceous tumors in a cohort containing 234 different tumors. The GATA6 expression score was significatively higher in sebaceous than that in nonsebaceous tumors. In addition, tumors originating from the upper hair follicle showed positive results for GATA6 staining; however, they showed lower GATA6 expression scores. Detection of sebaceous tumors using GATA6 positivity had a sensitivity of 95.7% (95% CI, 85.8-99.2), specificity of 80.8% (95% CI, 74.5-85.8), positive predictive value of 55.6% (95% CI, 44.7-65.9), and negative predictive value of 98.7% (95% CI, 95.4-99.8). GATA6 showed similar sensitivity to adipophilin, the reference marker; however, the specificity of GATA6 was higher, as observed in a cohort of 106 tumors enriched in squamous cell carcinomas with clear-cell histology. In addition, GATA6 positivity was assessed in 39 sebaceous carcinomas and compared with epithelial membrane antigen (EMA), CK7, and androgen receptor (AR) staining results. Although CK7 staining displayed lower diagnostic performances, GATA6 staining showed comparable results as EMA and AR. Finally, we found GATA6 expression in skin metastases of gastrointestinal origin, whereas GATA6 was absent in metastases originating from breast or lung cancers. Overall, our work identified GATA6 immunostaining as a new diagnostic tool for sebaceous tumors.

Acneiform Eruption Following Elexacaftor-Tezacaftor-Ivacaftor Treatment in Patients With Cystic Fibrosis.

Importance: A new treatment for cystic fibrosis combining 3 CFTR modulators-elexacaftor (ELX), tezacaftor (TEZ), and ivacaftor (IVA)-has recently been approved for cystic fibrosis treatment. The cutaneous adverse effects following treatment with this combination are poorly described in the literature. Objective: To describe the clinicopathological features and treatment response of ELX-TEZ-IVA-associated acneiform eruptions in patients with cystic fibrosis. Design, Setting, and Participants: This case series study was conducted in the Dermatology Department of Cochin Hospital, Paris, France, from July 2021 to June 2022 in collaboration with the Cochin Reference Center for Cystic Fibrosis. Referred patients were examined by senior dermatologists. All patients with cystic fibrosis treated with ELX-TEZ-IVA and referred for an acneiform rash were included. Exposures: Treatment with ELX-TEZ-IVA. Main Outcomes and Measures: Onset of acneiform rash, type of lesions, and degree of severity, as well as treatments initiated and response, were evaluated. When performed, skin biopsies were reviewed. Results: This study included 16 patients (11 women [68.7%]) with a median (range) age of 27 (22-38) years. Six patients (37.5%) developed new-onset acneiform rashes, whereas 10 patients (62.5%) had a relapse (5 patients) or worsening (5 patients) of previous acne. The median (range) onset of acneiform rash was 45 (15-150) days. At inclusion, 11 patients (68.7%) had facial hyperseborrhea, 15 patients (93.7%) had noninflammatory lesions, and 14 (87.5%) had inflammatory lesions of seborrheic regions. Four patients (25.0%) had severe acne with deep inflammatory lesions and pitted scars. A specific pathological pattern of necrotizing infundibular crystalline folliculitis was observed in 4 patients. Topical acne treatments, antibiotics, and isotretinoin were used successfully in these patients, resulting in partial or complete remission in 12 patients (85.7% of patients reevaluated). Conclusions and Relevance: This case series study found that acneiform eruption is an adverse event associated with ELX-TEZ-IVA treatment in patients with cystic fibrosis. Most patients developed mild lesions. However, isotretinoin treatment may be necessary in some patients. The mechanism of ELX-TEZ-IVA-associated acneiform eruption is currently unknown, but the observation of necrotizing infundibular crystalline folliculitis in biopsied patients may guide further exploration.

Clinicopathologic and molecular characterization of melanomas mutated for CTNNB1 and MAPK.

Wnt/ß-catenin signaling plays crucial roles in melanocyte biology and may be implicated in melanoma progression. In this study, we retrospectively examined a real-life cohort of melanomas mutated for ß-catenin (CTNNB1), in association or not with a MAPK mutation (of BRAF or NRAS), and analyzed their clinical, histopathological, and molecular characteristics. Our results indicate that, regardless of the presence of a concurrent MAPK mutation, CTNNB1mut cutaneous primary melanomas display more proliferative hallmarks (increased Breslow thickness, mitotic index, and ulceration) than their CTNNB1 wild-type counterparts. Accordingly, they often progress to the metastatic stage. Furthermore, concurrent CTNNB1 and MAPK mutations do not necessarily confer a deep penetrating nevi phenotype. Altogether, this study provides evidence that CTNNB1 mutations in melanomas are associated with specific clinical and pathological features.

Upregulation of the Sarco-Endoplasmic Reticulum Calcium ATPase 1 Truncated Isoform Plays a Pathogenic Role in Alzheimer's Disease.

Dysregulation of the Endoplasmic Reticulum (ER) Ca2+ homeostasis and subsequent ER stress activation occur in Alzheimer Disease (AD). We studied the contribution of the human truncated isoform of the sarco-endoplasmic reticulum Ca2+ ATPase 1 (S1T) to AD. We examined S1T expression in human AD-affected brains and its functional consequences in cellular and transgenic mice AD models. S1T expression is increased in sporadic AD brains and correlates with amyloid ß (Aß) and ER stress chaperone protein levels. Increased S1T expression was also observed in human neuroblastoma cells expressing Swedish-mutated ß-amyloid precursor protein (ßAPP) or treated with Aß oligomers. Lentiviral overexpression of S1T enhances in return the production of APP C-terminal fragments and Aß through specific increases of ß-secretase expression and activity, and triggers neuroinflammation. We describe a molecular interplay between S1T-dependent ER Ca2+ leak, ER stress and ßAPP-derived fragments that could contribute to AD setting and/or progression.

Single cell analysis of human foetal liver captures the transcriptional profile of hepatobiliary hybrid progenitors.

The liver parenchyma is composed of hepatocytes and bile duct epithelial cells (BECs). Controversy exists regarding the cellular origin of human liver parenchymal tissue generation during embryonic development, homeostasis or repair. Here we report the existence of a hepatobiliary hybrid progenitor (HHyP) population in human foetal liver using single-cell RNA sequencing. HHyPs are anatomically restricted to the ductal plate of foetal liver and maintain a transcriptional profile distinct from foetal hepatocytes, mature hepatocytes and mature BECs. In addition, molecular heterogeneity within the EpCAM+ population of freshly isolated foetal and adult human liver identifies diverse gene expression signatures of hepatic and biliary lineage potential. Finally, we FACS isolate foetal HHyPs and confirm their hybrid progenitor phenotype in vivo. Our study suggests that hepatobiliary progenitor cells previously identified in mice also exist in humans, and can be distinguished from other parenchymal populations, including mature BECs, by distinct gene expression profiles.

Mutant Lef1 controls Gata6 in sebaceous gland development and cancer.

Mutations in Lef1 occur in human and mouse sebaceous gland (SG) tumors, but their contribution to carcinogenesis remains unclear. Since Gata6 controls lineage identity in SG, we investigated the link between these two transcription factors. Here, we show that Gata6 is a ß-catenin-independent transcriptional target of mutant Lef1. During epidermal development, Gata6 is expressed in a subset of Sox9-positive Lef1-negative hair follicle progenitors that give rise to the upper SG Overexpression of Gata6 by in utero lentiviral injection is sufficient to induce ectopic sebaceous gland elements. In mice overexpressing mutant Lef1, Gata6 ablation increases the total number of skin tumors yet decreases the proportion of SG tumors. The increased tumor burden correlates with impaired DNA mismatch repair and decreased expression of Mlh1 and Msh2 genes, defects frequently observed in human sebaceous neoplasia. Gata6 specifically marks human SG tumors and also defines tumors with elements of sebaceous differentiation, including a subset of basal cell carcinomas. Our findings reveal that Gata6 controls sebaceous gland development and cancer.

Localization and Processing of the Amyloid-ß Protein Precursor in Mitochondria-Associated Membranes.

Alteration of mitochondria-associated membranes (MAMs) has been proposed to contribute to the pathogenesis of Alzheimer's disease (AD). We studied herein the subcellular distribution, the processing, and the protein interactome of the amyloid-ß protein precursor (AßPP) and its proteolytic products in MAMs. We reveal that AßPP and its catabolites are present in MAMs in cellular models overexpressing wild type AßPP or AßPP harboring the double Swedish or London familial AD mutations, and in brains of transgenic mice model of AD. Furthermore, we evidenced that both ß- and γ-secretases are present and harbor AßPP processing activities in MAMs. Interestingly, cells overexpressing APPswe show increased ER-mitochondria contact sites. We also document increased neutral lipid accumulation linked to Aß production and reversed by inhibiting ß- or γ-secretases. Using a proteomic approach, we show that AßPP and its catabolites interact with key proteins of MAMs controlling mitochondria and ER functions. These data highlight the role of AßPP processing and proteomic interactome in MAMs deregulation taking place in AD.

Ryanodine receptor blockade reduces amyloid-ß load and memory impairments in Tg2576 mouse model of Alzheimer disease.

In Alzheimer disease (AD), the perturbation of the endoplasmic reticulum (ER) calcium (Ca²âº) homeostasis has been linked to presenilins, the catalytic core in γ-secretase complexes cleaving the amyloid precursor protein (APP), thereby generating amyloid-ß (Aß) peptides. Here we investigate whether APP contributes to ER Ca²âº homeostasis and whether ER Ca²âº could in turn influence Aß production. We show that overexpression of wild-type human APP (APP(695)), or APP harboring the Swedish double mutation (APP(swe)) triggers increased ryanodine receptor (RyR) expression and enhances RyR-mediated ER Ca²âº release in SH-SY5Y neuroblastoma cells and in APP(swe)-expressing (Tg2576) mice. Interestingly, dantrolene-induced lowering of RyR-mediated Ca²âº release leads to the reduction of both intracellular and extracellular Aß load in neuroblastoma cells as well as in primary cultured neurons derived from Tg2576 mice. This Aß reduction can be accounted for by decreased Thr-668-dependent APP phosphorylation and ß- and γ-secretases activities. Importantly, dantrolene diminishes Aß load, reduces Aß-related histological lesions, and slows down learning and memory deficits in Tg2576 mice. Overall, our data document a key role of RyR in Aß production and learning and memory performances, and delineate RyR-mediated control of Ca²âº homeostasis as a physiological paradigm that could be targeted for innovative therapeutic approaches.

Identification of CANT1 mutations in Desbuquois dysplasia.

Desbuquois dysplasia is a severe condition characterized by short stature, joint laxity, scoliosis, and advanced carpal ossification with a delta phalanx. Studying nine Desbuquois families, we identified seven distinct mutations in the Calcium-Activated Nucleotidase 1 gene (CANT1), which encodes a soluble UDP-preferring nucleotidase belonging to the apyrase family. Among the seven mutations, four were nonsense mutations (Del 5' UTR and exon 1, p.P245RfsX3, p.S303AfsX20, and p.W125X), and three were missense mutations (p.R300C, p.R300H, and p.P299L) responsible for the change of conserved amino acids located in the seventh nucleotidase conserved region (NRC). The arginine substitution at position 300 was identified in five out of nine families. The specific function of CANT1 is as yet unknown, but its substrates are involved in several major signaling functions, including Ca2+ release, through activation of pyrimidinergic signaling. Importantly, using RT-PCR analysis, we observed a specific expression in chondrocytes. We also found electron-dense material within distended rough endoplasmic reticulum in the fibroblasts of Desbuquois patients. Our findings demonstrate the specific involvement of a nucleotidase in the endochondral ossification process.