Mutational Characterization of Cutaneous Melanoma Supports Divergent Pathways Model for Melanoma Development

This article belongs to the Special Issue Melanoma: Prevention and Molecular Epidemiology.[Simple Summary] The divergent pathway model established at least two approaches for melanoma development. One was related to a propensity to melanocytic proliferation (nevogenic), and the other was associated with an accumulation of solar damage (CSD). We conducted a retrospective study to examine whether this model had a molecular support using sequencing and bioinformatic tools on a set of cutaneous melanomas corresponding to these two groups. We found that the nevogenic melanomas were associated with mutations in BRAF, while the CSD melanomas were associated with mutations in NF1, ROS1, GNA11, and RAC1. We concluded that nevogenic and CSD melanomas constitute two different biological entities.[Abstract] According to the divergent pathway model, cutaneous melanoma comprises a nevogenic group with a propensity to melanocyte proliferation and another one associated with cumulative solar damage (CSD). While characterized clinically and epidemiologically, the differences in the molecular profiles between the groups have remained primarily uninvestigated. This study has used a custom gene panel and bioinformatics tools to investigate the potential molecular differences in a thoroughly characterized cohort of 119 melanoma patients belonging to nevogenic and CSD groups. We found that the nevogenic melanomas had a restricted set of mutations, with the prominently mutated gene being BRAF. The CSD melanomas, in contrast, showed mutations in a diverse group of genes that included NF1, ROS1, GNA11, and RAC1. We thus provide evidence that nevogenic and CSD melanomas constitute different biological entities and highlight the need to explore new targeted therapies.This study was supported by the Ministerio de Ciencia e Innovación-Instituto de Salud Carlos III (PI15/01860; PI19/00667), the Asociación Española Contra el Cáncer-Valencia through “Ayudas predoctorales en Oncología” grant, and the European Academy of Dermatology and Venereology (PPRC-2018-36)

Mutational Characterization of Cutaneous Melanoma Supports Divergent Pathways Model for Melanoma Development

From MDPI via Jisc Publications RouterHistory: accepted 2021-10-14, pub-electronic 2021-10-18Publication status: PublishedFunder: Instituto de Salud Carlos III; Grant(s): PI15/01860; PI19/00667Funder: EADV; Grant(s): PPRC-2018-36, Ayuda predoctoral en OncologíaAccording to the divergent pathway model, cutaneous melanoma comprises a nevogenic group with a propensity to melanocyte proliferation and another one associated with cumulative solar damage (CSD). While characterized clinically and epidemiologically, the differences in the molecular profiles between the groups have remained primarily uninvestigated. This study has used a custom gene panel and bioinformatics tools to investigate the potential molecular differences in a thoroughly characterized cohort of 119 melanoma patients belonging to nevogenic and CSD groups. We found that the nevogenic melanomas had a restricted set of mutations, with the prominently mutated gene being BRAF. The CSD melanomas, in contrast, showed mutations in a diverse group of genes that included NF1, ROS1, GNA11, and RAC1. We thus provide evidence that nevogenic and CSD melanomas constitute different biological entities and highlight the need to explore new targeted therapies

Ultraviolet light-induced collagen degradation inhibits melanoma invasion

From Springer Nature via Jisc Publications RouterHistory: received 2020-08-31, accepted 2021-04-08, registration 2021-04-11, online 2021-05-12, pub-electronic 2021-05-12, collection 2021-12Publication status: PublishedAbstract: Ultraviolet radiation (UVR) damages the dermis and fibroblasts; and increases melanoma incidence. Fibroblasts and their matrix contribute to cancer, so we studied how UVR modifies dermal fibroblast function, the extracellular matrix (ECM) and melanoma invasion. We confirmed UVR-damaged fibroblasts persistently upregulate collagen-cleaving matrix metalloprotein-1 (MMP1) expression, reducing local collagen (COL1A1), and COL1A1 degradation by MMP1 decreased melanoma invasion. Conversely, inhibiting ECM degradation and MMP1 expression restored melanoma invasion. Primary cutaneous melanomas of aged humans show more cancer cells invade as single cells at the invasive front of melanomas expressing and depositing more collagen, and collagen and single melanoma cell invasion are robust predictors of poor melanoma-specific survival. Thus, primary melanomas arising over collagen-degraded skin are less invasive, and reduced invasion improves survival. However, melanoma-associated fibroblasts can restore invasion by increasing collagen synthesis. Finally, high COL1A1 gene expression is a biomarker of poor outcome across a range of primary cancers

Mouse models in the study of malignant melanoma

Presentamos tres publicaciones que resumen la investigación de la propuesta doctoral en modelos de melanoma en ratón. En la primera publicación presentamos como la expresión del oncogén V600EBRAF en melanocitos de ratón adultos combinado con la expresión en queratinocitos adultos del mismo ratón de KITL logra traslocar los melanocitos de la dermis a la epidermis de los ratones. Sin embargo, la inclusión de melanocitos epidérmicos no logra generar un melanoma en el ratón que replique las características primordiales del melanoma en humanos. Los tumores en el ratón siguen siendo principalmente de ubicación dérmica, sin componente epidérmico, y no presenta una fase de crecimiento radial. Los tumores en el modelo V600EBRAF-KITL son muy invasivos y presentan destrucción local en la dermis, similares a los melanomas que surgen en el modelo V600EBRAF. Lo que si ocurre con el modelo de ratón V600EBRAF-KITL es que en la epidermis normal vemos el depósito de melanocitos en la epidermis interfolicular, algo no observado en ratones normales o ratones V600EBRAF. Igualmente, los nevus dérmicos que se forman tienen un fenotipo distinto, con mayor numero de células en la dermis papilar. Otro de los hallazgos importantes es que los melanomas que surgen en este modelo de ratón surgen en mayor numero (mayor penetrancia) y con una latencia más corta que los melanomas en el modelo tradicional V600EBRAF. Nuestro segundo estudio investiga la aparición de los carcinomas escamosos y los queratoacantomas (cSCC y KA) que surgen en 25% de pacientes como efecto secundario a los nuevos fármacos inhibidores del oncogén BRAF. Estos fármacos se han demostrado eficaces en el tratamiento del melanoma maligno metastático, prolongando la supervivencia de pacientes. En nuestro estudio, utilizamos un modelo de ratón de carcinogénesis de escamosos cutáneos para demostrar como la utilización de inhibidores de BRAF es capaz de acelerar la progresión tumoral en estos pacientes. Nuestra hipótesis es que la activación del oncogén RAS en queratinocitos puede interaccionar con inhibidores de BRAF para promover la proliferación celular, que llevaría al desarrollo de KA y cSCC en los pacientes. Nosotros demostramos evidencia indirecta que el mecanismo que subyace el desarrollo de tumores de estirpe queratinocítica en estos pacientes es la activación paradójica de la vía de proliferación celular MAP Kinase tanto en ratones como humanos. Los inhibidores de BRAF inhiben la vía MAP Kinase en células que portan una mutación BRAF, pero paradójicamente son capaces de inducir una activación de la misma vía en células que en lugar de mutación en BRAF tienen mutación en RAS. Nuestros resultados sugieren que las mutaciones en queratosis actínicas (lesiones premalignas precursoras de KA y cSCC) proliferan cuando los pacientes inician tratamiento con inhibidores de BRAF para su melanoma metastático. En nuestro tercer estudio demostramos como las lesiones inducidas por inhibidores de BRAF son altamente proliferativas y responden al antimetabolito 5-Fluorouracilo aprobado para el uso de lesiones queratinocíticas cutáneas premalignas. Nuestro modelo de ratón en este artículo nos permite desarrollar una nueva guía para el tratamiento de pacientes en estadios avanzados de melanoma metastático BRAF. Demostramos como la inhibición de MEK, una quinasa que señaliza en las últimas fases de activación de la vía MAP Kinase, es capaz de evitar el desarrollo de lesiones cutáneas, evitando la activación paradójica de MAP Kinase.We present three publications summarizing the investigations in mouse models of melanoma proposed as a subject for a doctoral thesis. In the first publication we present how oncogenic V600EBRAF expression in adult mouse melanocytes combined with KITL expression in mouse keratinocytes translocates melanocytes to the epidermis but does not lead to a more “humanized”form of melanoma. Tumours in this mouse model fail to replicate the cardinal features of V600EBRAF -driven human melanomas, where there is a prominent radial growth phase. Mice melanomas in the V600EBRAF-KITL model more closely resemble tumours induced in the V600EBRAF model without expression of KITL, where tumours are dermal, invasive, and present no radial growth phase. However, the V600EBRAF-KITL model translocates melanocytes to the epidermis and leads to the development of naevi of distinct phenotype. Importantly, coexpression of V600EBRAF and KITL leads to dermal melanomas that appear with a higher penetrance and shorter latency. Our second study shows how the recently approved BRAF inhibitors for the targeted treatment of metastatic malignant melanoma driven by oncogenic BRAF lead to the appearance of squamous cell carcinoma (SCC) and keratoacanthoma in approximately 25% of patients. Using a mouse model of skin carcinogenesis leading to the formation of SCC in mice, we show how the addition of a BRAF inhibitor accelerates the course of disease. We hypothesized that RAS activation in keratinocytes might interact with RAF inhibitor therapy to promote cell proliferation, ultimately resulting in KAs and cSCCs. We show indirect evidence the mechanism underlying SCC development in the context of BRAF inhibitor treatment is the paradoxical activation of the MAP Kinase pathway in both humans and mice. While RAF inhibitors inhibit mitogen-activated protein kinase (MAPK) signaling in BRAF-mutant melanoma cells, they may also cause a paradoxical increase in MAPK signaling in the context of mutated or activated RAS. Our results strongly suggest RAS mutations in actinic keratoses, the premalignant skin lesions with the potential to transform into cSCC, are driven to proliferate when treatment with a BRAF inhibitor is initiated. We show these lesions are highly proliferative in humans and in our mouse model, and respond to the FDA approved antiproliferative drug 5 Fluorouracil. Our mouse model also helps develop a new treatment rationale for metastatic melanoma with an underlying BRAF mutation. We show how downstream inhibition of the MAP Kinase pathway with a MEK inhibitor is able to abrogate the development of SCC

Mouse models in the study of malignant melanoma

Presentamos tres publicaciones que resumen la investigación de la propuesta doctoral en modelos de melanoma en ratón. En la primera publicación presentamos como la expresión del oncogén V600EBRAF en melanocitos de ratón adultos combinado con la expresión en queratinocitos adultos del mismo ratón de KITL logra traslocar los melanocitos de la dermis a la epidermis de los ratones. Sin embargo, la inclusión de melanocitos epidérmicos no logra generar un melanoma en el ratón que replique las características primordiales del melanoma en humanos. Los tumores en el ratón siguen siendo principalmente de ubicación dérmica, sin componente epidérmico, y no presenta una fase de crecimiento radial. Los tumores en el modelo V600EBRAF-KITL son muy invasivos y presentan destrucción local en la dermis, similares a los melanomas que surgen en el modelo V600EBRAF. Lo que si ocurre con el modelo de ratón V600EBRAF-KITL es que en la epidermis normal vemos el depósito de melanocitos en la epidermis interfolicular, algo no observado en ratones normales o ratones V600EBRAF. Igualmente, los nevus dérmicos que se forman tienen un fenotipo distinto, con mayor numero de células en la dermis papilar. Otro de los hallazgos importantes es que los melanomas que surgen en este modelo de ratón surgen en mayor numero (mayor penetrancia) y con una latencia más corta que los melanomas en el modelo tradicional V600EBRAF. Nuestro segundo estudio investiga la aparición de los carcinomas escamosos y los queratoacantomas (cSCC y KA) que surgen en 25% de pacientes como efecto secundario a los nuevos fármacos inhibidores del oncogén BRAF. Estos fármacos se han demostrado eficaces en el tratamiento del melanoma maligno metastático, prolongando la supervivencia de pacientes. En nuestro estudio, utilizamos un modelo de ratón de carcinogénesis de escamosos cutáneos para demostrar como la utilización de inhibidores de BRAF es capaz de acelerar la progresión tumoral en estos pacientes. Nuestra hipótesis es que la activación del oncogén RAS en queratinocitos puede interaccionar con inhibidores de BRAF para promover la proliferación celular, que llevaría al desarrollo de KA y cSCC en los pacientes. Nosotros demostramos evidencia indirecta que el mecanismo que subyace el desarrollo de tumores de estirpe queratinocítica en estos pacientes es la activación paradójica de la vía de proliferación celular MAP Kinase tanto en ratones como humanos. Los inhibidores de BRAF inhiben la vía MAP Kinase en células que portan una mutación BRAF, pero paradójicamente son capaces de inducir una activación de la misma vía en células que en lugar de mutación en BRAF tienen mutación en RAS. Nuestros resultados sugieren que las mutaciones en queratosis actínicas (lesiones premalignas precursoras de KA y cSCC) proliferan cuando los pacientes inician tratamiento con inhibidores de BRAF para su melanoma metastático. En nuestro tercer estudio demostramos como las lesiones inducidas por inhibidores de BRAF son altamente proliferativas y responden al antimetabolito 5-Fluorouracilo aprobado para el uso de lesiones queratinocíticas cutáneas premalignas. Nuestro modelo de ratón en este artículo nos permite desarrollar una nueva guía para el tratamiento de pacientes en estadios avanzados de melanoma metastático BRAF. Demostramos como la inhibición de MEK, una quinasa que señaliza en las últimas fases de activación de la vía MAP Kinase, es capaz de evitar el desarrollo de lesiones cutáneas, evitando la activación paradójica de MAP Kinase.We present three publications summarizing the investigations in mouse models of melanoma proposed as a subject for a doctoral thesis. In the first publication we present how oncogenic V600EBRAF expression in adult mouse melanocytes combined with KITL expression in mouse keratinocytes translocates melanocytes to the epidermis but does not lead to a more "humanized"form of melanoma. Tumours in this mouse model fail to replicate the cardinal features of V600EBRAF -driven human melanomas, where there is a prominent radial growth phase. Mice melanomas in the V600EBRAF-KITL model more closely resemble tumours induced in the V600EBRAF model without expression of KITL, where tumours are dermal, invasive, and present no radial growth phase. However, the V600EBRAF-KITL model translocates melanocytes to the epidermis and leads to the development of naevi of distinct phenotype. Importantly, coexpression of V600EBRAF and KITL leads to dermal melanomas that appear with a higher penetrance and shorter latency. Our second study shows how the recently approved BRAF inhibitors for the targeted treatment of metastatic malignant melanoma driven by oncogenic BRAF lead to the appearance of squamous cell carcinoma (SCC) and keratoacanthoma in approximately 25% of patients. Using a mouse model of skin carcinogenesis leading to the formation of SCC in mice, we show how the addition of a BRAF inhibitor accelerates the course of disease. We hypothesized that RAS activation in keratinocytes might interact with RAF inhibitor therapy to promote cell proliferation, ultimately resulting in KAs and cSCCs. We show indirect evidence the mechanism underlying SCC development in the context of BRAF inhibitor treatment is the paradoxical activation of the MAP Kinase pathway in both humans and mice. While RAF inhibitors inhibit mitogen-activated protein kinase (MAPK) signaling in BRAF-mutant melanoma cells, they may also cause a paradoxical increase in MAPK signaling in the context of mutated or activated RAS. Our results strongly suggest RAS mutations in actinic keratoses, the premalignant skin lesions with the potential to transform into cSCC, are driven to proliferate when treatment with a BRAF inhibitor is initiated. We show these lesions are highly proliferative in humans and in our mouse model, and respond to the FDA approved antiproliferative drug 5 Fluorouracil. Our mouse model also helps develop a new treatment rationale for metastatic melanoma with an underlying BRAF mutation. We show how downstream inhibition of the MAP Kinase pathway with a MEK inhibitor is able to abrogate the development of SCC

3D Bioprinting: An Enabling Technology to Understand Melanoma

Melanoma is a potentially fatal cancer with rising incidence over the last 50 years, associated with enhanced sun exposure and ultraviolet radiation. Its incidence is highest in people of European descent and the ageing population. There are multiple clinical and epidemiological variables affecting melanoma incidence and mortality, such as sex, ethnicity, UV exposure, anatomic site, and age. Although survival has improved in recent years due to advances in targeted and immunotherapies, new understanding of melanoma biology and disease progression is vital to improving clinical outcomes. Efforts to develop three-dimensional human skin equivalent models using biofabrication techniques, such as bioprinting, promise to deliver a better understanding of the complexity of melanoma and associated risk factors. These 3D skin models can be used as a platform for patient specific models and testing therapeutics

3D bioprinting: an enabling technology to understand melanoma

SIMPLE SUMMARY: Melanoma is a form of skin cancer that has increased in incidence in the last few decades. The main environmental risk factor is exposure to ultraviolet radiation (UVR). It is the fifth most common cancer in the UK, with a 17% mortality rate. There are new melanoma therapies that show improvement in patient survival; however, there is a significant proportion of patients who do not respond to approved treatments, for whom there are no second line therapies. Developing safe new therapies without significant side effects for patients is a pressing clinical challenge; 3D skin equivalents allow for disease modelling and systematic and safe drug testing for skin cancer. This paper reviews recent advances in creating 3D skin and cancer models for effective drug screening for melanoma. ABSTRACT: Melanoma is a potentially fatal cancer with rising incidence over the last 50 years, associated with enhanced sun exposure and ultraviolet radiation. Its incidence is highest in people of European descent and the ageing population. There are multiple clinical and epidemiological variables affecting melanoma incidence and mortality, such as sex, ethnicity, UV exposure, anatomic site, and age. Although survival has improved in recent years due to advances in targeted and immunotherapies, new understanding of melanoma biology and disease progression is vital to improving clinical outcomes. Efforts to develop three-dimensional human skin equivalent models using biofabrication techniques, such as bioprinting, promise to deliver a better understanding of the complexity of melanoma and associated risk factors. These 3D skin models can be used as a platform for patient specific models and testing therapeutics

Distribution and clinical role of KIT gene mutations in melanoma according to subtype: a study of 492 Spanish patients

KIT mutations are primarily associated with acral and mucosal melanoma, and have been reported to show higher prevalence in chronic sun-damaged (CSD) than non-CSD melanomas. The aim is to investigate the prevalence of KIT mutations in melanoma according to subtype, and to determine the clinical role of such mutations.Medicin

Mutational Characterization of Cutaneous Melanoma Supports Divergent Pathways Model for Melanoma Development

According to the divergent pathway model, cutaneous melanoma comprises a nevogenic group with a propensity to melanocyte proliferation and another one associated with cumulative solar damage (CSD). While characterized clinically and epidemiologically, the differences in the molecular profiles between the groups have remained primarily uninvestigated. This study has used a custom gene panel and bioinformatics tools to investigate the potential molecular differences in a thoroughly characterized cohort of 119 melanoma patients belonging to nevogenic and CSD groups. We found that the nevogenic melanomas had a restricted set of mutations, with the prominently mutated gene being BRAF. The CSD melanomas, in contrast, showed mutations in a diverse group of genes that included NF1, ROS1, GNA11, and RAC1. We thus provide evidence that nevogenic and CSD melanomas constitute different biological entities and highlight the need to explore new targeted therapies.Medicin