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RASopathies are a diverse group of genetic conditions caused by hyperactivation of the RAS-MAPK signaling pathway, mainly inherited in an autosomal dominant manner. They present with variable features such as short stature, congenital heart defects, facial dysmorphisms, and neurodevelopmental delays. This study retrospectively analyzed 143 cases from 2003 to 2022, aiming to improve genotype–phenotype correlation knowledge for personalized care. Patients with genetically confirmed Noonan syndrome (NS) and related disorders were included, with molecular analysis performed via Sanger or parallel sequencing. Data from 906 previously reported cases were also reviewed. Among the 143 patients, most had NS (n = 116). PTPN11 mutations were most frequent (61%), followed by SOS1 (10.3%) and RAF1 (8.6%). Cardiac anomalies were observed in 71%, with pulmonary stenosis (PS) prevalent in NS (48.3%) and hypertrophic cardiomyopathy (HCM) in NSML (40%). PTPN11 variants were linked to PS and atrial septal defects, SOS1 to multiple cardiopathies, and RAF1 to HCM. Additional features included facial dysmorphisms (74.1%), short stature (62.0%), skeletal anomalies (43.1%), cryptorchidism (59.7%), and brain abnormalities (17.2%). JMML and other malignancies were seen in eight patients. This study emphasizes the importance of genotype-guided care, improved diagnosis of mild cases, and the underrecognized prevalence of neurological anomalies.

Background The main drawback of BRAF/MEK inhibitors (BRAF/MEKi)-based targeted therapy in the management of BRAF-mutated cutaneous metastatic melanoma (MM) is the development of therapeutic resistance. We aimed to assess in this context the role of mTORC2, a signaling complex defined by the presence of the essential RICTOR subunit, regarded as an oncogenic driver in several tumor types, including MM. Methods After analyzing The Cancer Genome Atlas MM patients’ database to explore both overall survival and molecular signatures as a function of intra-tumor RICTOR levels, we investigated the effects of RICTOR downregulation in BRAF V600E MM cell lines on their response to BRAF/MEKi. We performed proteomic screening to identify proteins modulated by changes in RICTOR expression, and Seahorse analysis to evaluate the effects of RICTOR depletion on mitochondrial respiration. The combination of BRAFi with drugs targeting proteins and processes emerged in the proteomic screening was carried out on RICTOR-deficient cells in vitro and in a xenograft setting in vivo. Results Low RICTOR levels in BRAF-mutated MM correlate with a worse clinical outcome. Gene Set Enrichment Analysis of low-RICTOR tumors display gene signatures suggestive of activation of the mitochondrial Electron Transport Chain (ETC) energy production. RICTOR-deficient BRAF V600E cells are intrinsically tolerant to BRAF/MEKi and anticipate the onset of resistance to BRAFi upon prolonged drug exposure. Moreover, in drug-naïve cells we observed a decline in RICTOR expression shortly after BRAFi exposure. In RICTOR-depleted cells, both mitochondrial respiration and expression of nicotinamide phosphoribosyltransferase (NAMPT) are enhanced, and their pharmacological inhibition restores sensitivity to BRAFi. Conclusions Our work unveils an unforeseen tumor-suppressing role for mTORC2 in the early adaptation phase of BRAF V600E melanoma cells to targeted therapy and identifies the NAMPT-ETC axis as a potential therapeutic vulnerability of low RICTOR tumors. Importantly, our findings indicate that the evaluation of intra-tumor RICTOR levels has a prognostic value in metastatic melanoma and may help to guide therapeutic strategies in a personalized manner.

Background p130 Crk-associated substrate (p130CAS; also known as BCAR1) is a scaffold protein that modulates many essential cellular processes such as cell adhesion, proliferation, survival, cell migration, and intracellular signaling. p130Cas has been shown to be highly expressed in a variety of human cancers of epithelial origin. However, few data are available regarding the role of p130Cas during normal epithelial development and homeostasis. Methods To this end, we have generated a genetically modified mouse in which p130Cas protein was specifically ablated in the epidermal tissue. Results By using this murine model, we show that p130Cas loss results in increased cell proliferation and reduction of cell adhesion to extracellular matrix. In addition, epidermal deletion of p130Cas protein leads to premature expression of “late” epidermal differentiation markers, altered membrane E-cadherin/catenin proteins localization and aberrant tyrosine phosphorylation of E-cadherin/catenin complexes. Interestingly, these alterations in adhesive properties in absence of p130Cas correlate with abnormalities in progenitor cells balance resulting in the amplification of a more committed cell population. Conclusion Altogether, these results provide evidence that p130Cas is an important regulator of epidermal cell fate and homeostasis.

Following publication of the original article [1], the authors reported an error in the name of the 11th author. The author's name was incorrectly published as \"Vincenzo Calautti\", instead of \"Enzo Calautti\".

The main drawback of BRAF/MEK inhibitors (BRAF/MEKi)-based targeted therapy in the management of BRAF-mutated cutaneous metastatic melanoma (MM) is the development of therapeutic resistance. We aimed to assess in this context the role of mTORC2, a signaling complex defined by the presence of the essential RICTOR subunit, regarded as an oncogenic driver in several tumor types, including MM. After analyzing The Cancer Genome Atlas MM patients' database to explore both overall survival and molecular signatures as a function of intra-tumor RICTOR levels, we investigated the effects of RICTOR downregulation in BRAF MM cell lines on their response to BRAF/MEKi. We performed proteomic screening to identify proteins modulated by changes in RICTOR expression, and Seahorse analysis to evaluate the effects of RICTOR depletion on mitochondrial respiration. The combination of BRAFi with drugs targeting proteins and processes emerged in the proteomic screening was carried out on RICTOR-deficient cells in vitro and in a xenograft setting in vivo. Low RICTOR levels in BRAF-mutated MM correlate with a worse clinical outcome. Gene Set Enrichment Analysis of low-RICTOR tumors display gene signatures suggestive of activation of the mitochondrial Electron Transport Chain (ETC) energy production. RICTOR-deficient BRAF cells are intrinsically tolerant to BRAF/MEKi and anticipate the onset of resistance to BRAFi upon prolonged drug exposure. Moreover, in drug-naïve cells we observed a decline in RICTOR expression shortly after BRAFi exposure. In RICTOR-depleted cells, both mitochondrial respiration and expression of nicotinamide phosphoribosyltransferase (NAMPT) are enhanced, and their pharmacological inhibition restores sensitivity to BRAFi. Our work unveils an unforeseen tumor-suppressing role for mTORC2 in the early adaptation phase of BRAF melanoma cells to targeted therapy and identifies the NAMPT-ETC axis as a potential therapeutic vulnerability of low RICTOR tumors. Importantly, our findings indicate that the evaluation of intra-tumor RICTOR levels has a prognostic value in metastatic melanoma and may help to guide therapeutic strategies in a personalized manner.