The C-terminus of the prototypical M2 muscarinic receptor localizes to the mitochondria and regulates cell respiration under stress conditions.

Muscarinic acetylcholine receptors are prototypical G protein-coupled receptors (GPCRs), members of a large family of 7 transmembrane receptors mediating a wide variety of extracellular signals. We show here, in cultured cells and in a murine model, that the carboxyl terminal fragment of the muscarinic M2 receptor, comprising the transmembrane regions 6 and 7 (M2tail), is expressed by virtue of an internal ribosome entry site localized in the third intracellular loop. Single-cell imaging and import in isolated yeast mitochondria reveals that M2tail, whose expression is up-regulated in cells undergoing integrated stress response, does not follow the normal route to the plasma membrane, but is almost exclusively sorted to the mitochondria inner membrane: here, it controls oxygen consumption, cell proliferation, and the formation of reactive oxygen species (ROS) by reducing oxidative phosphorylation. Crispr/Cas9 editing of the key methionine where cap-independent translation begins in human-induced pluripotent stem cells (hiPSCs), reveals the physiological role of this process in influencing cell proliferation and oxygen consumption at the endogenous level. The expression of the C-terminal domain of a GPCR, capable of regulating mitochondrial function, constitutes a hitherto unknown mechanism notably unrelated to its canonical signaling function as a GPCR at the plasma membrane. This work thus highlights a potential novel mechanism that cells may use for controlling their metabolism under variable environmental conditions, notably as a negative regulator of cell respiration.

Molecular Profile of Subungual Melanoma: A MelaNostrum Consortium Study of 68 Cases Reporting BRAF, NRAS, KIT, and TERT Promoter Status.

BACKGROUND: Subungual melanoma (SM) is an unusual type of melanocytic tumor affecting the nail apparatus. The mutational prevalence of the most prominently mutated genes in melanoma has been reported in small cohorts of SM, with unclear conclusions on whether SM is different from the rest of melanomas arising in acral locations or not. Hence, the molecular profile of a large series of SM is yet to be described. OBJECTIVES: The aim of this study was to describe the molecular characteristics of a large series of SM and their association with demographic and histopathological features. METHODS: Patients diagnosed with SM between 2001 and 2021 were identified from six Spanish and Italian healthcare centers. The mutational status for BRAF, NRAS, KIT, and the promoter region of TERT (TERTp) were determined either by Sanger sequencing or next-generation sequencing. Clinical data were retrieved from the hospital databases to elucidate potential associations. RESULTS: A total of 68 SM cases were included. Mutations were most common in BRAF (10.3%) and KIT (10%), followed by NRAS (7.6%), and TERTp (3.8%). Their prevalence was similar to that of non-subungual acral melanoma but higher in SM located on the hand than on the foot. CONCLUSIONS: To date, this study represents the largest cohort of SM patients with data on the known driver gene mutations. The low mutation rate supports a different etiopathogenic mechanism for SM in comparison of non-acral cutaneous melanoma, particularly for SM of the foot.

The dynamics of circulating tumour DNA (ctDNA) during treatment reflects tumour response in advanced melanoma patients.

Despite the introduction of targeted (BRAFi/MEKi) and immune checkpoint inhibitors (ICIs) has significantly reduced the recurrence rate and improved the overall survival (OS) of patients with Stage III and IV melanoma, only a percentage will benefit of durable disease control. The aim of this study was to examine whether the levels of circulating tumour DNA (ctDNA) in plasma of advanced melanoma patients undergoing BRAFi/MEKi or ICIs vary according to the patients' survival outcomes (i.e. progression-free survival (PFS) and OS) and disease progression. Plasma samples of Stage III-IV melanoma patients were collected at baseline (treatment initiation) and thereafter every 3 months. Circulating BRAFV600E/K and NRASQ61R/K mutations were analysed through droplet digital PCR (ddPCR, Bio-Rad) in a total of 177 plasma samples from 48 melanoma patients (19 Stage III, 29 Stage IV). Baseline ctDNA concentration was significantly associated with OS (HR = 1.003, 95% CI = 1.000-1.006, p = 0.043) and PFS (HR = 1.004, 95% CI = 1.000-1.007, p = 0.029) independent of clinical-prognostic confounders. For each unit increase in the ∆ctDNA (concentration difference between the last follow-up and baseline) there was a 24% increased risk of disease progression, irrespective of treatment type and stage at diagnosis (OR = 1.24, 95% CI = 1.03-1.49, p = 0.020, AUC = 0.93). Patients with reduction of ctDNA level from baseline to the last follow-up had longer OS (HR = 0.14; 95% CI = 0.05-0.44, p = 0.001) and PFS (HR = 0.08; 95% CI = 0.03-0.27, p < 0.0001) compared to patients with increased ctDNA, including adjustment for confounding factors. Our findings suggest that variation of ctDNA over time during melanoma treatment reflects the clinical outcome and tumour response to therapy and might be helpful in clinical monitoring.

"Your Skin Tells You" Campaign for Keratinocyte Cancers: When Individuals' Selection Makes the Difference.

BACKGROUND: Prevention campaigns for skin cancers have focused primarily on melanoma, and over time there has been increasing awareness of the need to select the population to be screened to maximize program effectiveness. OBJECTIVES: The objective of the study was to report the results of a free dermatological initiative, as part of an awareness campaign dedicated to keratinocyte cancers, targeting individuals pre-selected through a short questionnaire. METHODS: One day of dermatological consultations was held at 15 dermato-oncology referral centers during May 22-June 30, 2021. For selection, individuals answered a telephone interview consisting of 7 yes/no questions on risk factors. Demographics, clinical characteristics of suspicious tumors, and histopathologic diagnosis of excised lesions were collected. Suspicion rate, detection rate, and positive predictive values (PPVs) for any skin cancer, basal cell carcinoma (BCC), cutaneous squamous cell carcinoma (cSCC), and melanoma were calculated. RESULTS: A total of 320 individuals (56.9% males; 43.1% females) with a median age of 69.6 (range 21-91) years qualified for the screening initiative. Overall, skin cancers and precancerous lesions were diagnosed in 65.9% of the patients. Suspicion rate was 28.7% for any skin cancer (92/320), 22.8% for BCC (73/320), 4.7% for cSCC (15/320), and 1.2% for melanoma (4/320). Detection rate was 23.4% for any skin cancer (PPV 93.7%), 18.1% for BCC (PPV 95.1%), 4.4% for cSCC (PPV 93.3%), and 0.9% for melanoma (PPV 75%). CONCLUSIONS: Selection of individuals at high risk is a cost-effective approach for early detection campaigns for keratinocyte cancers.

Updates on liquid biopsy: current trends and future perspectives for clinical application in solid tumors.

Despite advances in screening and therapeutics cancer continues to be one of the major causes of morbidity and mortality worldwide. The molecular profile of tumor is routinely assessed by surgical or bioptic samples, however, genotyping of tissue has inherent limitations: it represents a single snapshot in time and it is subjected to spatial selection bias owing to tumor heterogeneity. Liquid biopsy has emerged as a novel, non-invasive opportunity of detecting and monitoring cancer in several body fluids instead of tumor tissue. Circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), RNA (mRNA and microRNA), microvesicles, including exosomes and tumor "educated platelets" were recently identified as a source of genomic information in cancer patients which could reflect all subclones present in primary and metastatic lesions allowing sequential monitoring of disease evolution. In this review, we summarize the currently available information concerning liquid biopsy in breast cancer, colon cancer, lung cancer and melanoma. These promising issues still need to be standardized and harmonized across laboratories, before fully adopting liquid biopsy approaches into clinical practice.

Satisfaction and attitudes toward systemic treatments for psoriasis: A cross-sectional study.

In psoriasis patients, satisfaction and patients' attitude toward treatment are heterogeneous depending on several factors and remain poorly investigated, although the availability of several new targeted therapeutic options. A multicentre cross-sectional investigation was conducted to estimate treatment satisfaction and attitudes (awareness, trust, and therapeutic alliance) in a large population of adult psoriasis patients undergoing a systemic biologic or non-biologic agent for moderate-to-severe plaque-type psoriasis. Patients' satisfaction was measured using the Treatment Satisfaction Questionnaire for Medication II questionnaire and patients' attitudes toward treatment were evaluated using a Lickert scale. Results were related to patients' and treatment characteristics and therapeutic outcomes. The study included 899 psoriasis patients and demonstrated high-treatment satisfaction and positive attitudes toward systemic treatments, with greater influence of the perceived efficacy and the type of treatment. Biologic treatments and, in particular anti-IL17 agents showed higher results. More efforts in developing tools facilitating communication and exploring important aspects of patients' view are needed.

Combining common genetic variants and non-genetic risk factors to predict risk of cutaneous melanoma.

Melanoma heritability is among the highest for cancer and single nucleotide polymorphisms (SNPs) contribute to it. To date, only SNPs that reached statistical significance in genome-wide association studies or few candidate SNPs have been included in melanoma risk prediction models. We compared four approaches for building polygenic risk scores (PRS) using 12 874 melanoma cases and 23 203 controls from Melanoma Meta-Analysis Consortium as a training set, and newly genotyped 3102 cases and 2301 controls from the MelaNostrum consortium for validation. We estimated adjusted odds ratios (ORs) for melanoma risk using traditional melanoma risk factors and the PRS with the largest area under the receiver operator characteristics curve (AUC). We estimated absolute risks combining the PRS and other risk factors, with age- and sex-specific melanoma incidence and competing mortality rates from Italy as an example. The best PRS, including 204 SNPs (AUC = 64.4%; 95% confidence interval (CI) = 63-65.8%), developed using winner's curse estimate corrections, had a per-quintile OR = 1.35 (95% CI = 1.30-1.41), corresponding to a 3.33-fold increase comparing the 5th to the 1st PRS quintile. The AUC improvement by adding the PRS was up to 7%, depending on adjusted factors and country. The 20-year absolute risk estimates based on the PRS, nevus count and pigmentation characteristics for a 60-year-old Italian man ranged from 0.5 to 11.8% (relative risk  = 26.34), indicating good separation.

Intra-patient Heterogeneity of BRAF and NRAS Molecular Alterations in Primary Melanoma and Metastases.

Mutations in MAPK signalling genes are driver events in melanoma, and have therapeutic relevance in the metastatic and adjuvant setting. This study evaluated the intra-patient heterogeneity of BRAF, NRAS and c-KIT mutational status between 30 primary melanomas and 39 related metastases, using molecular analysis and immunohistochemistry. BRAF mutations were identified in 46.7% of primary melanomas and 48.7% of metastases and NRAS mutations in 20% and 25.6%, respectively. Intra-patient heterogeneity was detected in 13.3% of patients for both BRAF and NRAS genes and was not associated with clinico-pathological characteristics of melanomas or metastases. High consistency was observed between immunostaining and molecular methods for BRAFV600E (k = 0.90; p < 0.001) and NRASQ61R (k = 0.87; p < 0.001). These findings demonstrate a relevant intra-patient heterogeneity between primary and metastatic lesions that is independent of clinical variables and methodological approach.

Dermoscopic similarity is an independent predictor of BRAF mutational concordance in multiple melanomas.

BACKGROUND: The association of clinical and dermoscopic features with BRAF mutational status has been poorly analysed in multiple primary melanomas (MPM). OBJECTIVE: To investigate whether concordance of BRAF mutational status is associated with dermoscopic similarity in multiple melanomas of the same patient. METHODS: Dermoscopic images and corresponding tissue sections of 124 melanomas from 62 patients with MPM were selected at four Italian Dermatology Departments. Similarity of dermoscopic appearance between multiple melanomas was evaluated according to the presence of the same prevalent dermoscopic feature. The BRAFV600 mutational status was analysed with allele-specific TaqManTM assays or pyrosequencing. Spearman's correlation and univariate and multivariate regression analysis were used for statistical analysis. RESULTS: A similar dermoscopic appearance was identified in 38.7% (24/62) of patients with MPM and was correlated with older age at first diagnosis (rho: 0.26; P: 0.042) and occurrence on sun-damaged skin (rho: 0.27; P: 0.037). The BRAFV600 mutation was detected in 39.5% (49/124) of the tumors and a concordant BRAF mutational status between melanomas in 33/62 (53.2%) MPM patients. Dermoscopically similar melanomas showed 5.7-fold higher odds to be concordant for BRAF mutational status compared to dissimilar lesions (OR: 5.7; 95% CI 1.7-19.5; P: 0.005). CONCLUSION: Dermoscopic similarity of multiple melanomas represents an independent clinical predictor of a concordant BRAF mutational status in MPM patients.

Melanoma types by in vivo reflectance confocal microscopy correlated with protein and molecular genetic alterations: A pilot study.

Cutaneous melanoma (CM) is one of the most prevalent skin cancers, which lacks both a prognostic marker and a specific and lasting treatment, due to the complexity of the disease and heterogeneity of patients. Reflectance confocal microscopy (RCM) in vivo analysis is a versatile approach offering immediate morphological information, enabling the identification of four primary cutaneous RCM CM types. Whether RCM CM types are associated with a specific protein and molecular genetic profiles at the tissue level remains unclear. The current pilot study was designed to identify potential correlations between RCM CM types and specific biological characteristics, combining immunohistochemistry (IHC) and molecular analyses. Eighty primary CMs evaluated at patient bedside with RCM (type 1 [19, 24%], type 2 [12, 15%], type 3 [7, 9%] and type 4 [42, 52%]) were retrospectively evaluated by IHC stains (CD271, CD20, CD31, cyclin D1), fluorescence in situ hybridization FISH for MYC gain and CDKN2A loss and molecular analysis for somatic mutations (BRAF, NRAS and KIT). RCM CM types correlated with markers of stemness property, density of intra-tumoral lymphocytic B infiltrate and cyclin D1 expression, while no significant association was found with blood vessel density nor molecular findings. RCM CM types show a different marker profile expression, suggestive of a progression and an increase in aggressiveness, according to RCM morphologies.

Telomeres and Telomerase in Cutaneous Squamous Cell Carcinoma.

The role of telomere biology and telomerase activation in skin cancers has been investigated in melanoma and basal cell carcinoma but limited evidence is available for cutaneous squamous cell carcinoma (cSCC). We will review the current knowledge on the role of telomere and telomerase pathway in cSCC pathogenesis. At the somatic level, both long and short telomere lengths have been described in cSCC. This telomere dichotomy is probably related to two different mechanisms of tumour initiation which determines two tumour subtypes. Telomere shortening is observed during the invasive progression from in situ forms of cSCC, such as Bowen's disease (BD) and actinic keratosis (AK), to invasive cSCC. At the germline level, controversial results have been reported on the association between constitutive telomere length and risk of cSCC. Approximately 75⁻85% of cSCC tumours are characterized by a high level of telomerase activity. Telomerase activation has been also reported in AKs and BD and in sun-damaged skin, thus supporting the hypothesis that UV modulates telomerase activity in the skin. Activating TERT promoter mutations have been identified in 32⁻70% of cSCCs, with the majority showing the UV-signature. No significant correlation was observed between TERT promoter mutations and cSCC clinico-pathological features. However, TERT promoter mutations have been recently suggested to be independent predictors of an adverse outcome. The attention on telomere biology and telomerase activity in cSCC is increasing for the potential implications in the development of effective tools for prognostic assessment and of therapeutic strategies in patients with cutaneous cSCC.

Understanding the Molecular Genetics of Basal Cell Carcinoma.

Basal cell carcinoma (BCC) is the most common human cancer and represents a growing public health care problem. Several tumor suppressor genes and proto-oncogenes have been implicated in BCC pathogenesis, including the key components of the Hedgehog pathway, PTCH1 and SMO, the TP53 tumor suppressor, and members of the RAS proto-oncogene family. Aberrant activation of the Hedgehog pathway represents the molecular driver in basal cell carcinoma pathogenesis, with the majority of BCCs carrying somatic point mutations, mainly ultraviolet (UV)-induced, and/or copy-loss of heterozygosis in the PTCH1 gene. Recent advances in sequencing technology allowed genome-scale approaches to mutation discovery, identifying new genes and pathways potentially involved in BCC carcinogenesis. Mutational and functional analysis suggested PTPN14 and LATS1, both effectors of the Hippo-YAP pathway, and MYCN as new BCC-associated genes. In addition, emerging reports identified frequent non-coding mutations within the regulatory promoter sequences of the TERT and DPH3-OXNAD1 genes. Thus, it is clear that a more complex genetic network of cancer-associated genes than previously hypothesized is involved in BCC carcinogenesis, with a potential impact on the development of new molecular targeted therapies. This article reviews established knowledge and new hypotheses regarding the molecular genetics of BCC pathogenesis.

Does Locoregional Chemotherapy Still Matter in the Treatment of Advanced Pelvic Melanoma?

Pelvic Melanoma relapse occurs in 15% of patients with loco regional metastases, and 25% of cases do not respond to new target-therapy and/or immunotherapy. Melphalan hypoxic pelvic perfusion may, therefore, be an option for these non-responsive patients. Overall median survival time (MST), stratified for variables, including BRAF V600E mutation and eligibility for treatments with new immunotherapy drugs, was retrospectively assessed in 41 patients with pelvic melanoma loco regional metastases. They had received a total of 175 treatments with Melphalan hypoxic perfusion and cytoreductive excision. Among the 41 patients, 22 (53.7%) patients exhibited a wild-type BRAF genotype, 11 of which were not eligible for immunotherapy. The first treatment resulted in a 97.5% response-rate in the full cohort and a 100% response-rate in the 22 wild-type BRAF patients. MST was 18 months in the full sample, 20 months for the 22 wild-type BRAF patients and 21 months for the 11 wild-type BRAF patients not eligible for immunotherapy. Melphalan hypoxic perfusion is a potentially effective treatment for patients with pelvic melanoma loco regional metastases that requires confirmation in a larger multicenter study.

Kinetic Studies on CphA Mutants Reveal the Role of the P158-P172 Loop in Activity versus Carbapenems.

Site-directed mutagenesis of CphA indicated that prolines in the P158-P172 loop are essential for the stability and the catalytic activity of subclass B2 metallo-ß-lactamases against carbapenems. The sequential substitution of proline led to a decrease of the catalytic efficiency of the variant compared to the wild-type (WT) enzyme but also to a higher affinity for the binding of the second zinc ion.

Photodynamic Therapy for the Treatment of Bowen's Disease: A Review on Efficacy, Non-Invasive Treatment Monitoring, Tolerability, and Cosmetic Outcome.

Bowen's disease represents the in situ form of cutaneous squamous cell carcinoma; although it has an excellent prognosis, 3-5% of lesions progress to invasive cutaneous squamous cell carcinoma, with a higher risk in immunocompromised patients. Treatment is therefore always necessary, and conventional photodynamic therapy is a first-line option. The aim of this review is to provide an overview of the clinical response, recurrence rates, safety, and cosmetic outcome of photodynamic therapy in the treatment of Bowen's disease, considering different protocols in terms of photosensitizers, light source, and combination treatments. Photodynamic therapy is a valuable option for tumors at sites where wound healing is poor/delayed, in the case of multiple and/or large tumors, and where surgery would be difficult or invasive. Dermoscopy and reflectance confocal microscopy can be used as valuable tools for monitoring the therapeutic response. The treatment is generally well tolerated, with mild side effects, and is associated with a good/excellent cosmetic outcome. Periodic follow-up after photodynamic therapy is essential because of the risk of recurrence and progression to cSCC. As the incidence of keratinocyte tumors increases, the therapeutic space for photodynamic therapy will further increase.

Exploring the interplay of atopic dermatitis severity with sleep and mental health: a case-control study in adult patients.

OBJECTIVES: Atopic dermatitis (AD) is a chronic inflammatory skin disease often associated with non-atopic comorbidities. Recently, a severity-dependent relationship between AD and sleep/mental health diseases has been proposed. However, few studies investigated these comorbidities and their association with AD severity through validated questionnaires. This study aimed to use a set of validated instruments to assess the impact of AD on sleep and psychological disorders and estimate the association of itch and AD severity with sleep disorders and psychological symptoms, distinguishing between clinical-oriented and patient-oriented measures. METHODS: We conducted a case-control study, recruiting 57 adult AD patients (mean age ± std. dev. 34.28 years ± 13.07; 27 males) matched for age and sex with 57 healthy adults (34.39 years ± 13.09; 27 males). To investigate the differences in sleep quality, insomnia, depression, and anxiety between the two groups, we performed independent sample t-Tests. Moreover, we conducted univariate linear regression analyses to examine the relationship between itch and objective/subjective severity of AD and sleep quality, insomnia, and psychological symptoms. RESULTS: AD patients reported lower sleep quality (p = 0.002), more severe insomnia (p = 0.006) and depression (p = 0.013), and higher stress levels than healthy adults (p = 0.049). Itch intensity was linked to sleep disturbances and psychological symptoms (R2range = 0.13-0.19, prange = 0.02-<0.001). Objective and subjective AD severity were similarly associated with worse sleep quality (R2 = 0.26, p < 0.001; R2 = 0.24, p < 0.001; respectively), anxiety (R2 = 0.15, p = 0.04; R2 = 0.17, p = 0.001; respectively), and self-perceived stress (R2 = 0.10, p = 0.02; R2 = 0.07, p = 0.049; respectively). However, subjective AD severity was more strongly associated with insomnia (R2 = 0.31, p < 0.001) and depression (R2 = 0.20, p < 0.001) than clinical-oriented AD severity (R2 = 0.19, p < 0.001; R2 = 0.05, p = 0.098; respectively). CONCLUSIONS: The study demonstrated poor sleep quality and high levels of insomnia, depression, and stress in AD patients, with an aggravated psychological status for adults with more severe skin disease. We suggest implementing a multidisciplinary approach to AD management/treatment that considers objective and subjective measures of disease severity.

R164H and V240H replacements by site-directed mutagenesis of TEM-149 extended-spectrum ß-lactamase: kinetic analysis of TEM-149H240 and TEM-149H164-H240 laboratory mutants.

Two laboratory mutant forms, TEM-149(H240) and TEM-149(H164-H240), of the TEM-149 extended-spectrum ß-lactamase enzyme were constructed by site-directed mutagenesis. TEM-149(H240) and TEM-149(H164-H240) were similar in kinetic behavior, except with respect to benzylpenicillin and ceftazidime. Molecular modeling of the two mutant enzymes demonstrated the role of histidine at position 240 in the reduction of the affinity of the enzyme for ceftazidime.

Cytokine profile characterization of naïve patients with psoriasis and psoriatic arthritis: implications for a pathogenic disease continuum.

Background: The idea of psoriatic disease continuum has been progressively prompted based on the advances of the knowledge about the pathogenic steps underpinning the occurrence of psoriasis (PSO) and psoriatic arthritis (PSA). To evaluate biomolecules (inflammatory cytokines, inflammatory chemokines, cell adhesion and cellular mediators) in naïve patients with PSO, PSA with PSO, and PSA sine PSO. To stratify the results considering the presence of psoriatic nail involvement, extensive skin disease and obesity evaluating all involved patients. Methods: By multiplex technology, 20 serum biomolecules were assessed with the inclusion of pro-inflammatory cytokines (GM-CSF, IFN-γ, IL-1α, IL-1ß, IL-6, IL-8, IL-12p70, IL-17A, IL-23, TNF), anti-inflammatory cytokines (IFN-α, IL-4, IL-10, IL-13), inflammatory chemokines (IP-10, MCP-1, MIP-1α, MIP-1ß), cell adhesion and cellular mediators (ICAM-1, E-selectin, P-selectin). The assessment of possible statistical differences between the means of the three groups was performed by One-Way ANOVA. In addition, by non-parametric T-tests, we stratified the results according to selected clinical characteristics (psoriatic nail involvement, PASI ≥ 10, BMI ≥ 30). Results: In 80 assessed naïve patients, patients with PSO showed significant increases of E-selectin (p=0.021) and IL-8 (0.041) than other groups. In patients with PSA with PSO, significant higher levels of ICAM-1 were observed (p=0.009) than other groups. We did not observe further differences comparing pro-inflammatory and anti-inflammatory cytokines, inflammatory chemokines, and cell adhesion and cellular mediators in patients with PSO, PSA with PSO, and PSA sine PSO. Patients with psoriatic onychopathy showed significant increased levels of ICAM-1 (p=0.010) and IP-10 (0.030) than others. In patients with PASI ≥ 10, significantly enhanced values of IL-8 (p=0.004), TNF (p=0.013), E-selectin (p=0.004), MIP-1α (p=0.003), and MIP-1ß (p=0.039). In patients with BMI ≥ 30, significantly higher levels of E-selectin were pointed out (p=0.035) than others. Conclusion: Our findings may suggest that a similar cytokine profile may characterize naïve patients with PSO, PSA with PSO, and PSA sine PSO, reinforcing the concept of psoriatic disease continuum. However, some differences may be also shown, underlying possible pathogenic differences and leading to the clinical heterogeneity of these patients.

The Alternative TrkAIII Splice Variant, a Targetable Oncogenic Participant in Human Cutaneous Malignant Melanoma.

Post-therapeutic relapse, poor survival rates and increasing incidence justify the search for novel therapeutic targets and strategies in cutaneous malignant melanoma (CMM). Within this context, a potential oncogenic role for TrkA in CMM is suggested by reports of NTRK1 amplification, enhanced TrkA expression and intracellular TrkA activation associated with poor prognosis. TrkA, however, exhibits tumour-suppressing properties in melanoma cell lines and has recently been reported not to be associated with CMM progression. To better understand these contradictions, we present the first analysis of potential oncogenic alternative TrkA mRNA splicing, associated with TrkA immunoreactivity, in CMMs, and compare the behaviour of fully spliced TrkA and the alternative TrkAIII splice variant in BRAF(V600E)-mutated A375 melanoma cells. Alternative TrkA splicing in CMMs was associated with unfolded protein response (UPR) activation. Of the several alternative TrkA mRNA splice variants detected, TrkAIII was the only variant with an open reading frame and, therefore, oncogenic potential. TrkAIII expression was more frequent in metastatic CMMs, predominated over fully spliced TrkA mRNA expression in ≈50% and was invariably linked to intracellular phosphorylated TrkA immunoreactivity. Phosphorylated TrkA species resembling TrkAIII were also detected in metastatic CMM extracts. In A375 cells, reductive stress induced UPR activation and promoted TrkAIII expression and, in transient transfectants, promoted TrkAIII and Akt phosphorylation, enhancing resistance to reductive stress-induced death, which was prevented by lestaurtinib and entrectinib. In contrast, fully spliced TrkA was dysfunctional in A375 cells. The data identify fully spliced TrkA dysfunction as a novel mechanism for reducing melanoma suppression, support a causal relationship between reductive stress, UPR activation, alternative TrkAIII splicing and TrkAIII activation and characterise a targetable oncogenic pro-survival role for TrkAIII in CMM.

T Cell Immunoglobulin and Mucin Domain 3 (TIM-3) in Cutaneous Melanoma: A Narrative Review.

T cell immunoglobulin and mucin domain 3 (TIM-3) is an inhibitory immunocheckpoint that belongs to the TIM gene family. Monney et al. first discovered it about 20 years ago and linked it to some autoimmune diseases; subsequent studies have revealed that some tumours, including melanoma, have the capacity to produce inhibitory ligands that bind to these receptor checkpoints on tumour-specific immune cells. We conducted a literature search using PubMed, Web of Science (WoS), Scopus, Google Scholar, and Cochrane, searching for the following keywords: "T cell immunoglobulin and mucin-domain containing-3", "TIM-3" and/or "Immunocheckpoint inhibitors" in combination with "malignant melanoma" or "human malignant melanoma" or "cutaneous melanoma". The literature search initially turned up 117 documents, 23 of which were duplicates. After verifying eligibility and inclusion criteria, 17 publications were ultimately included. A growing body of scientific evidence considers TIM-3 a valid inhibitory immuno-checkpoint with a very interesting potential in the field of melanoma. However, other recent studies have discovered new roles for TIM-3 that seem almost to contradict previous findings in this regard. All this demonstrates how common and valid the concept of 'pleiotropism' is in the TME field, in that the same molecule can behave completely or partially differently depending on the cell type considered or on temporary conditions. Further studies, large case series, and a special focus on the immunophenotype of TIM-3 are absolutely necessary in order to explore this highly promising topic in the near future.