Topical therapy for regression and melanoma prevention of congenital giant nevi

Nevi and Melanoma

Cutaneous melanoma is an aggressive form of skin cancer derived from skin melanocytes and is associated with significant morbidity and mortality. A significant fraction of melanomas are associated with precursor lesions, benign clonal proliferations of melanocytes called nevi. Nevi can be either congenital or acquired later in life. Identical oncogenic driver mutations are found in benign nevi and melanoma. While much progress has been made in our understanding of nevus formation and the molecular steps required for transformation of nevi into melanoma, the clinical diagnosis of benign versus malignant lesions remains challenging.

Alpelisib decreases nevocytes of congenital melanocytic nevi

BACKGROUND

Multiple, large or giant congenital melanocytic nevi (CMN) are uncommon and affected patients can show progressive growth and thickening, associate neurocutaneous melanocytosis or develop melanoma. Current treatment modalities are mostly complex surgeries that frequently do not solve the disease and its risks completely. Thus, investigation on new treatment options for CMN and its complications must continue. MAPK pathway inhibitors are being investigated, also targeting PI3K-AKT. Omipalisib (PI3K inhibitor, with no indications approved yet) has been studied for CMN in vitro and in mice with promising results. However, alpelisib, a PI3K inhibitor approved with an adequate safety profile for patients with severe manifestations of PROS (PIK3CA-Related Overgrowth Spectrum), had not yet been tested for CMN.

OBJECTIVE

To evaluate the effect of alpelisib in nevocytes of congenital melanocytic nevi.

METHODS

Nevomelanocytic tissue samples of 10 patients were collected prospectively and, following a previously reported preclinical ex vivo model, explants were placed in organotypic culture for 5 days, with or without alpelisib. Consecutively, tissue sections were stained and using scanned images with Qupath and ImageJ softwares, representative regions from the dermis were analysed (using Wilcoxon test and Spearman's correlation).

RESULTS

When comparing alpelisib-treated explants with respect to control explants, we found a decrease in cell density (p = 0.0273), in density of SOX10+-cells (p = 0.0391) and also in the % of S-100+ area (p = 0.0078), in alpelisib samples. The three markers showed a positive correlation (p < 0.05).

CONCLUSIONS

This study provides first-time evidence that alpelisib induces nevocyte reduction in CMN from patient-derived explants, probably inducted by autophagy. Alpelisib is an approved drug with an adequate safety profile used in another mosaicism affecting PI3K (PROS). Further studies are needed to evaluate its efficacy in treating CMN and potentially, their complications, either with local or systemic administration, alone or in combination.

Modulation of tumor plasticity by senescent cells: Deciphering basic mechanisms and survival pathways to unravel therapeutic options

Senescence is a cellular state in which the cell loses its proliferative capacity, often irreversibly. Physiologically, it occurs due to a limited capacity of cell division associated with telomere shortening, the so-called replicative senescence. It can also be induced early due to DNA damage, oncogenic activation, oxidative stress, or damage to other cellular components (collectively named induced senescence). Tumor cells acquire the ability to bypass replicative senescence, thus ensuring the replicative immortality, a hallmark of cancer. Many anti-cancer therapies, however, can lead tumor cells to induced senescence. Initially, this response leads to a slowdown in tumor growth. However, the longstanding accumulation of senescent cells (SnCs) in tumors can promote neoplastic progression due to the enrichment of numerous molecules and extracellular vesicles that constitutes the senescence-associated secretory phenotype (SASP). Among other effects, SASP can potentiate or unlock the tumor plasticity and phenotypic transitions, another hallmark of cancer. This review discusses how SnCs can fuel mechanisms that underlie cancer plasticity, like cell differentiation, stemness, reprogramming, and epithelial-mesenchymal transition. We also discuss the main molecular mechanisms that make SnCs resistant to cell death, and potential strategies to target SnCs. At the end, we raise open questions and clinically relevant perspectives in the field.

A BEST classification system of large to giant congenital melanocytic nevi based on expert consensus and distribution characteristics

BACKGROUND

Large to giant congenital melanocytic nevi (LGCMN) significantly decrease patients' quality of life, but the inaccuracy of current classification system makes their clinical management challenging.

OBJECTIVES

To improve and extend the existing LGCMN 6B/7B classification systems by developing a novel LGCMN classification system based on a new phenotypic approach to clinical tool development.

METHODS

Three hundred and sixty-one LGCMN cases were categorized into four subtypes based on anatomic site: bonce (25.48%), extremity (17.73%), shawl (19.67%) and trunks (37.12%) LGCMN. A 'BEST' classification system of LGCMN was established and validated by a support vector machine classifier combined with the 7B system.

RESULTS

The most common LGCMN distributions were on bonce and trunks (bathing trunk), whereas breast/belly and body LGCMN were exceptionally rare. Sexual dimorphism characterized distribution, with females showing a wider range of lesions in the genital area. Nearly half of the patients with bathing trunk LGCMN exhibited a butterfly-like distribution. Approximately half of the LGCMN with chest involvement did not have nipple-areola complex involvement. Abdomen, back and buttock involvement was associated with the presence of satellite nevi (r = 0.558), and back and buttock involvement was associated with the presence of nodules (r = 0.364).

CONCLUSIONS

The effective quantification of a standardized anatomical site provides data support for the accuracy of the 6B/7B classification systems. The simplified BEST classification system can help establish a LGCMN clinical database for exploration of LGCMN aetiology, disease management and prognosis prediction.

Erbium: YAG laser treatment efficacy and association with histologic features for giant congenital melanocytic nevi management

BACKGROUND

Limited research exists on laser treatment of giant congenital melanocytic nevus (GCMN).

OBJECTIVE

We sought to elucidate the efficacy of the Erbium: YAG laser on GCMN and the histologic factors associated with a positive clinical response.

METHODS AND MATERIALS

Between 2019 and 2022, we enrolled 30 medium-to-giant CMN patients who underwent Er: YAG laser treatment. All patients received biopsies before and after laser treatments. Clinical efficacy outcomes were evaluated by the investigator's global assessment (IGA), 5-point scale of depigmentation, and Vancouver Scar Scale (VSS) scores at least 6 months after treatment.

RESULTS

Of the 30 cases, 18 (60.0%) showed improvement (IGA score ≥3). Eight (26.7%) patients showed repigmentation. Eight (26.7%) patients developed hypertrophic scars. The average IGA, depigmentation, and VSS scores were 2.93, 3.57, and 3.20. The IGA score was higher (3.24 ± 1.18 vs. 2.22 ± 0.97, p = 0.031) and a lower repigmentation rate (14.3% vs. 55.6%, p = 0.032) was observed in the cases with Grenz zone. The IGA score was higher (3.33 ± 1.24 vs. 2.13 ± 0.89, p = 0.023) and the repigmentation rate was lower (11.1% vs. 50.0%, p = 0.034) also in the cases with the melanocytes nests with aggregation of melanin. Lesions with superficial ablation resulted in less hypertrophic scar formation than those with deep ablation (5.9% vs. 53.8%, p < 0.05).

CONCLUSION

The Er: YAG laser demonstrated effective clinical results for GCMNs. The grenz zone and the melanocytes nests with aggregation of melanin are promising predictors of laser efficacy.

Updates in the Management of Congenital Melanocytic Nevi

Congenital melanocytic nevi (CMN) carry an increased risk of melanoma and may be disfiguring, and consensus regarding treatment recommendations is lacking. While clinical monitoring is the standard of care, many caregivers are interested in its removal to prevent psychosocial burden or to decrease risk. Although melanoma can occur regardless of CMN removal, there are a variety of treatments that may offer improved cosmesis or local symptom control, including surgical excision, laser therapy, and other superficially destructive techniques. Regardless of the selected management, these patients are monitored for ongoing melanoma risk. An extensive discussion with families regarding the risks and benefits of observation versus active intervention is essential. To facilitate these discussions, we herein summarize current CMN management strategies and considerations.

A clinical and biologic review of congenital melanocytic nevi

Congenital melanocytic nevi (CMN) are the result of aberrations in the mitogen-activated protein kinase signal transduction pathway caused by postzygotic somatic mutations. The estimated incidence of newborns with CMN is 1%-2%. The main complications of CMN include proliferative nodules, melanomas, and neurocutaneous melanosis, and the latter two are the most troublesome issues to address. Treatments are primarily taken into account for aesthetic purposes and the reduction of melanoma risk. Due to the much lower incidence of malignant transformation observed in recent studies than in previous data, clinical management paradigms for CMN patients have gradually shifted towards conservative observation and close monitoring. Surgery and lasers are still the main treatments, and targeted therapy may be a promising strategy to help manage complications. With the increase in awareness of mental health, increasing focus has been placed on the quality of life (QoL) and psychological issues of both CMN patients and their parents. Recent studies have revealed that families coping with CMN might endure intense pressure, a major loss in QoL, and psychological problems after diagnosis and during treatment. Here, we sought to present an overview of genetic basis, complications, treatments, and psychological issues related to CMN and hope to provide better management for patients with CMN.

Oxocarbon Acids and their Derivatives in Biological and Medicinal Chemistry

The biological and medicinal chemistry of the oxocarbon acids 2,3- dihydroxycycloprop-2-en-1-one (deltic acid), 3,4-dihydroxycyclobut-3-ene-1,2-dione (squaric acid), 4,5-dihydroxy-4-cyclopentene-1,2,3-trione (croconic acid), 5,6-dihydroxycyclohex- 5-ene-1,2,3,4-tetrone (rhodizonic acid) and their derivatives is reviewed and their key chemical properties and reactions are discussed. Applications of these compounds as potential bioisosteres in biological and medicinal chemistry are examined. Reviewed areas include cell imaging, bioconjugation reactions, antiviral, antibacterial, anticancer, enzyme inhibition, and receptor pharmacology.

Incidence of neurocutaneous melanosis in Japanese pediatric patients with congenital melanocytic nevi

Neurocutaneous melanosis (NCM) is a rare, non-hereditary neurocutaneous disorder characterized by excessive melanocytic proliferation in the skin and central nervous system. As no major studies have covered the incidence of NCM among Japanese patients with congenital melanocytic nevi (CMN), we prospectively investigated the incidence of NCM among Japanese patients who underwent initial treatment for CMN. The relationship of CMN and NCM was also investigated. Japanese pediatric patients with CMN under 1 year of age were included between January 2020 and November 2022, and all patients underwent brain MRI to check for NCM in this study. NCM lesions were most frequently seen in the amygdala, followed by the cerebellum, brainstem, and cerebral hemispheres. NCM was diagnosed on brain MRI in 31.6% of the 38 patients with CMN and in 25.0% of patients with no prior examination or treatment. Distribution and size of CMN, number of satellite nevi, rugosity and nodules were strongly associated with the existence of NCM, and these findings may guide a future registry study with a large cohort of CMN patients.

Signalling by senescent melanocytes hyperactivates hair growth

Niche signals maintain stem cells in a prolonged quiescence or transiently activate them for proper regeneration¹. Altering balanced niche signalling can lead to regenerative disorders. Melanocytic skin nevi in human often display excessive hair growth, suggesting hair stem cell hyperactivity. Here, using genetic mouse models of nevi^2,3, we show that dermal clusters of senescent melanocytes drive epithelial hair stem cells to exit quiescence and change their transcriptome and composition, potently enhancing hair renewal. Nevus melanocytes activate a distinct secretome, enriched for signalling factors. Osteopontin, the leading nevus signalling factor, is both necessary and sufficient to induce hair growth. Injection of osteopontin or its genetic overexpression is sufficient to induce robust hair growth in mice, whereas germline and conditional deletions of either osteopontin or CD44, its cognate receptor on epithelial hair cells, rescue enhanced hair growth induced by dermal nevus melanocytes. Osteopontin is overexpressed in human hairy nevi, and it stimulates new growth of human hair follicles. Although broad accumulation of senescent cells, such as upon ageing or genotoxic stress, is detrimental for the regenerative capacity of tissue⁴, we show that signalling by senescent cell clusters can potently enhance the activity of adjacent intact stem cells and stimulate tissue renewal. This finding identifies senescent cells and their secretome as an attractive therapeutic target in regenerative disorders.

Making a mouse out of a molehill: how precision modeling repurposes drugs for congenital giant nevi

Patients with congenital giant nevi (CGN), which can compromise quality of life and progress to melanoma, have limited treatment options. Choi et al. have demonstrated that topical application of a proinflammatory hapten for alopecia treatment [squaric acid dibutylester (SADBE)] caused nevus regression and prevented melanoma in an Nras mouse CGN model. Their results demonstrate the promise of repurposing drugs through precision modeling.