Inherited duplications of PPP2R3B predispose to nevi and melanoma via a C21orf91-driven proliferative phenotype

PURPOSE

Much of the heredity of melanoma remains unexplained. We sought predisposing germline copy-number variants using a rare disease approach.

METHODS

Whole-genome copy-number findings in patients with melanoma predisposition syndrome congenital melanocytic nevus were extrapolated to a sporadic melanoma cohort. Functional effects of duplications in PPP2R3B were investigated using immunohistochemistry, transcriptomics, and stable inducible cellular models, themselves characterized using RNAseq, quantitative real-time polymerase chain reaction (qRT-PCR), reverse phase protein arrays, immunoblotting, RNA interference, immunocytochemistry, proliferation, and migration assays.

RESULTS

We identify here a previously unreported genetic susceptibility to melanoma and melanocytic nevi, familial duplications of gene PPP2R3B. This encodes PR70, a regulatory unit of critical phosphatase PP2A. Duplications increase expression of PR70 in human nevus, and increased expression in melanoma tissue correlates with survival via a nonimmunological mechanism. PPP2R3B overexpression induces pigment cell switching toward proliferation and away from migration. Importantly, this is independent of the known microphthalmia-associated transcription factor (MITF)-controlled switch, instead driven by C21orf91. Finally, C21orf91 is demonstrated to be downstream of MITF as well as PR70.

CONCLUSION

This work confirms the power of a rare disease approach, identifying a previously unreported copy-number change predisposing to melanocytic neoplasia, and discovers C21orf91 as a potentially targetable hub in the control of phenotype switching.

Stability of jabuticaba flakes obtained by drum drying with cassava starch as additive

Abstract The stability of jabuticaba flakes produced by drum drying using cassava starch as additive was evaluated. Sorption isotherms at 25 ºC were determined. Samples were stored under controlled conditions (relative humidity = 60%, temperature = 20, 25 and 35 ºC) for until 235 days. The anthocyanin content and color parameters (L*, a* and b*) were monitored. GAB model led to the best adjustment of sorption isotherm, with a monolayer moisture value of 0.1596 g water/g dry basis. The visual observations did not point out agglomerations and darkening at aw values higher than 0.33 at 25 ºC, which can be considered the critical point. The degradation of anthocyanin and color parameters followed first and zero-order kinetic model, respectively. The half-life times (630 to 1450 days) showed good stability at 25 ºC, while the temperature acceleration coefficient (2.2 ≤ Q10 ≤ 3.2) and activation energy (15 ≤ Ea ≤ 19 kcal/mol) values demonstrated a high-temperature sensitivity.

Melanocortin-1 receptor (MC1R) genotypes do not correlate with size in two cohorts of medium-to-giant congenital melanocytic nevi

Congenital melanocytic nevi (CMN) are cutaneous malformations whose prevalence is inversely correlated with projected adult size. CMN are caused by somatic mutations, but epidemiological studies suggest that germline genetic factors may influence CMN development. In CMN patients from the U.K., genetic variants in MC1R, such as p.V92M and loss-of-function variants, have been previously associated with larger CMN. We analyzed the association of MC1R variants with CMN characteristics in two distinct cohorts of medium-to-giant CMN patients from Spain (N = 113) and from France, Norway, Canada, and the United States (N = 53), similar at the clinical and phenotypical level except for the number of nevi per patient. We found that the p.V92M or loss-of-function MC1R variants either alone or in combination did not correlate with CMN size, in contrast to the U.K. CMN patients. An additional case-control analysis with 259 unaffected Spanish individuals showed a higher frequency of MC1R compound heterozygous or homozygous variant genotypes in Spanish CMN patients compared to the control population (15.9% vs. 9.3%; p = .075). Altogether, this study suggests that MC1R variants are not associated with CMN size in these non-UK cohorts. Additional studies are required to define the potential role of MC1R as a risk factor in CMN development.

Sutton Naevi as Melanoma Simulators: Can Confocal Microscopy Help in the Diagnosis?

Sutton naevi can sometimes present a challenging appearance with atypical presentation, also by dermoscopy. Reflectance confocal microscopy could help in making a diagnosis. This study prospectively collected two groups of Sutton nevi: the first one was composed by typical white halo naevi monitored for one year (13, 23%) and the second one was made up of atypical lesions excised in order to rule out melanoma, which were histologically diagnosed as Sutton naevi (21, 37%). These two groups of Sutton naevi were compared to a retrospectively collected cohort of thin melanomas with histologic regression features (23, 40%). On dermoscopy, atypical Sutton naevi and melanomas were indistinguishable. Reflectance confocal microscopy demonstrated significant differences at the dermo–epidermal junction: marked dermo–epidermal junction thickening and non-edged papilla were associated with melanoma, while the presence of nests was associated with Sutton naevi. However, reflectance confocal microscopy also detected marked intraepidermal pagetoid cells in Sutton naevi that were a combination of MelanA⁺ and CD1a+ cells. Sutton naevi can simulate melanoma, under both dermoscopy and reflectance confocal microscopy. Nevertheless, relevant confocal dermo–epidermal junction features and the clinical scenario can be helpful to make a final diagnosis, especially in those situations where melanoma must be ruled out.

Physicochemical and rheological properties of soybean organogels: Interactions between different structuring agents

High consumption of trans and saturated fats has been related to the development of cardiovascular diseases, justifying the application of organogels as possible substitutes for industrial fats. The aim of this study was to evaluate the physicochemical and rheological characteristics of soybean organogels that were prepared with 6% (w:w) of structuring components by a simplex centroid design, individually added, in binary and ternary associations with candelilla wax (CW), sorbitan monostearate (SMS) and fully hydrogenated palm oil (HPO). The formulated organogels were evaluated for hardness, solid content, and rheological behavior. The organogels containing a high proportion of HPO had higher solid content: 8.1% with the addition of isolated HPO and a solid content of 6.9% with the addition of HPO + CW. However, isolated use of HPO resulted in lower compression/extrusion strength (0.85 N) than that obtained with isolated CW (10.45 N). All organogels exhibited Hershel-Bulkley rheological behavior, except organogel 2 (containing only SMS), which showed pseudoplastic behavior. Thus, the structuring agents used to form the organogels are capable of changing the physical behavior of unsaturated lipids depending on whether a combination of CW + HPO was added, a ternary interaction with a higher proportion of CW, and the use of isolated CW as a structuring agent, resulting in organogels of greater stability and hardness.

Genetic Abnormalities in Large to Giant Congenital Nevi: Beyond NRAS Mutations

Large and giant congenital melanocytic nevi (CMN) are rare melanocytic lesions mostly caused by postzygotic NRAS alteration. Molecular characterization is usually focused on NRAS and BRAF genes in a unique biopsy sample of the CMN. However, large/giant CMN may exhibit phenotypic differences among distinct areas, and patients differ in features such as presence of multiple CMN or spilus-like lesions. Herein, we have characterized a series of 21 large/giant CMN including patients with spilus-type nevi (9/21 patients, 42.8%). Overall, 53 fresh frozen biopsy samples corresponding to 40 phenotypically characterized areas of large/giant CMNs and 13 satellite lesions were analyzed with a multigene panel and RNA sequencing. Mutational screening showed mutations in 76.2% (16/21) of large/giant CMNs. A NRAS mutation was found in 57.1% (12/21) of patients, and mutations in other genes such as BRAF, KRAS, APC, and MET were detected in 14.3% (3/21) of patients. RNA sequencing showed the fusion transcript ZEB2-ALK and SOX5-RAF1 in large/giant CMN from two patients without missense mutations. Both alterations were not detected in unaffected skin and were detected in different areas of affected skin. These findings suggest that large/giant CMN may result from distinct molecular events in addition to NRAS mutations, including point mutations and fusion transcripts.

Respiratory and Systemic Effects of LASSBio596 Plus Surfactant in Experimental Acute Respiratory Distress Syndrome

BACKGROUND/AIMS

Exogenous surfactant has been proposed as adjunctive therapy for acute respiratory distress syndrome (ARDS), but it is inactivated by different factors present in the alveolar space. We hypothesized that co-administration of LASSBio596, a molecule with significant anti-inflammatory properties, and exogenous surfactant could reduce lung inflammation, thus enabling the surfactant to reduce edema and improve lung function, in experimental ARDS.

METHODS

ARDS was induced by cecal ligation and puncture surgery in BALB/c mice. A sham-operated group was used as control (CTRL). After surgery (6 hours), CTRL and ARDS animals were assigned to receive: (1) sterile saline solution; (2) LASSBio596; (3) exogenous surfactant or (4) LASSBio596 plus exogenous surfactant (n = 22/group).

RESULTS

Regardless of exogenous surfactant administration, LASSBio596 improved survival rate and reduced collagen fiber content, total number of cells and neutrophils in PLF and blood, cell apoptosis, protein content in BALF, and urea and creatinine levels. LASSBio596 plus surfactant yielded all of the aforementioned beneficial effects, as well as increased BALF lipid content and reduced surface tension.

CONCLUSION

LASSBio596 exhibited major anti-inflammatory and anti-fibrogenic effects in experimental sepsis-induced ARDS. Its association with surfactant may provide further advantages, potentially by reducing surface tension.