RESUMO
PURPOSE: Cutaneous adverse effects from cyclin-dependent 4 and 6 kinase inhibitors (CDK4/6i) used in metastatic breast cancer are prevalent and well described. Vitiligo-like lesions have been reported and are rare. They can negatively impact patients' quality of life and may be associated with survival benefits. We describe the clinical characteristics of vitiligo-like lesions in an international cohort of patients treated with CDK4/6i to help improve recognition and management. METHODS: Retrospective review of patients diagnosed with vitiligo-like lesions from CDK4/6i from five academic institutions in the USA and Europe was performed. Ten patients were included in the study. RESULTS: Median age of our patients was 55 (range 37-86). Median progression-free survival was 24 months in 5 patients. The median time to rash was 10 months. Sun-exposed areas such as the arms and face were the most affected areas. Multiple skin-directed therapies such as topicals, laser, and phototherapy were trialed with minor success. Mild repigmentation was seen in one patient treated with ruxolitinib cream. CDK4/6 treatment was discontinued due to the vitiligo-like lesions in one patient. CONCLUSION: Clinical characteristics are similar to previously reported findings in case reports and series. We add topical ruxolitinib as a potential treatment option for these patients and include data regarding progression-free survival that should continue to be collected. No definitive conclusions can be made regarding survival benefits from our cohort. Clinicians should refer these patients to dermatologists to aid with management.
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Neoplasias da Mama , Nitrilas , Pirazóis , Pirimidinas , Vitiligo , Humanos , Feminino , Neoplasias da Mama/complicações , Neoplasias da Mama/tratamento farmacológico , Aminopiridinas , Piridinas/efeitos adversos , Vitiligo/tratamento farmacológico , Vitiligo/induzido quimicamente , Estudos Retrospectivos , Quinase 4 Dependente de Ciclina , Qualidade de Vida , Inibidores de Proteínas Quinases/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêuticoRESUMO
INTRODUCTION: Cutaneous adverse reactions to epidermal growth factor receptor inhibitors (EGFRi) are some of the most common side effects that patients experience. However, cutaneous adverse reactions that cause dyspigmentation in patients have been rarely reported. Erythema dyschromicum perstans (EDP) is a rare pigmentary condition that causes ashy-grey hyperpigmented macules and patches, with a few cases reported from EGFRi in the literature. The disfiguration caused by this condition may negatively impact patients' quality of life. Our study aimed to describe the clinical characteristics of EDP induced by EGFRi to better recognize and manage the condition. METHODS: We conducted a multicenter retrospective review at three academic institutions to identify patients with EDP induced by EGFRi from 2017 to 2023 and included sixteen patients in our study. RESULTS: The median age of patients was 66 years old, with 63% female and 37% male (Table 1). The majority of our patients were Asian (88%). All patients had non-small cell lung cancer and most patients received osimertinib. Median time to EDP was 6 months. The most common areas of distribution were the head/neck region, lower extremities, and upper extremities. Various topical ointments were trialed; however, approximately less than half had improvement in their disease and most patients had persistent EDP with no resolution. All patients desired treatment except one with EDP on the tongue, and there was no cancer treatment discontinuation or interruption due to EDP. Table 1 Patient demographics and clinical characteristics of 16 patients with EDP induced by EGFRi Case no Demographics: age, race, and sex Fitzpatrick skin type Cancer type EGFR therapy Concomitant photosensitive drug(s) Time to EDP (months) Clinical features Distribution Symptoms Treatments and clinical course EDP status from most recent follow up 1 47 y/o Asian male III Stage IV NSCLC Erlotinib None Unknown Brown-blue-gray hyperpigmented patches Bilateral shins Left thigh Xerosis Pruritus Triamcinolone 0.1% ointment for 4 months, improvement of blue discoloration Tacrolimus 0.1% BID for 9 months, improvement but no resolution Ongoing 2 62 y/o Asian female IV Stage IV NSCLC Osimertinib None 4 Gray-brown hyperpigmented patches Bilateral arms Back Forehead Neck Right shin None Tacrolimus 0.1% ointment for 1 year with minor improvement Ongoing 3 69 y/o Asian female IV Stage IV NSCLC Osimertinib None 4 Gray-brown macules and patches Chest Face Forehead Bilateral legs None Tacrolimus 0.1% ointment for 10 months, no improvement Ongoing 4 79 y/o White male II Stage IV NSCLC Osimertinib None 15 Mottled grey-blue hyperpigmented patches and plaques with mild scaling Bilateral arms Back Forehead Neck None Photoprotection, no improvement Ongoing 5 69 y/o Asian female III Stage IV NSCLC Osimertinib Ibuprofen 4 Blue-grey hyperpigmented macules and patches Abdomen Bilateral arms None Tacrolimus 0.1% ointment for 7 months, no improvement Ongoing 6 65 y/o Asian male III Stage IV NSCLC Osimertinib None 20 Hyperpigmented blue gray macules and patches Helix Bilateral shins None Photoprotection, no improvement Ongoing 7 66 y/o Asian female IV Stage IV NSCLC Erlotinib TMP-SMX 6 Ashy grey-brown thin plaques Back Forehead None 2.5% hydrocortisone ointment for 8 months, resolved Resolved 8 82 y/o Asian male III Stage III NSCLC Erlotinib Simvastatin 20 Ash-grey hyperpigmented patches Dorsal feet Forehead Scalp None Photoprotection Ongoing 9 57 y/o Asian female III Stage II NSCLC Erlotinib None 1 Bue-grey discoloration Tongue None No intervention Ongoing 10 51 y/o Asian female III Stage IV NSCLC Osimertinib None 9 Blue-grey hyperpigmented macules and patches Bilateral arms Axillae Groin Neck Trunk None 2.5% hydrocortisone ointment, triamcinolone 0.1% ointment, photoprotection with mild improvement Ongoing 11 67 y/o Asian male III Stage IV NSCLC Osimertinib None 7 Gray-blue macules and patches with mild background erythema and scaling Bilateral arms Ears Face Bilateral shins None Triamcinolone 0.1% ointment, protection for 6 months with mild improvement Ongoing 12 75 y/o Asian female IV Stage III NSCLC Osimertinib TMP-SMX 3 Gray-blue hyperpigmented patches Bilateral arms Abdomen Back Face Bilateral shins Pruritus Triamcinolone 0.1% and betamethasone 0.01% with relief of pruritus, lesions unchanged Triluma cream 6 months, mild improvement Ongoing 13 42 y/o Asian male IV Stage IV NSCLC Afatinib TMP-SMX 24 Grey-brown hyperpigmented patches Back Face None Hydroquinone 4% cream for 2 years with mild improvement Ongoing 14 74 y/o White female III Stage II NSCLC Osimertinib Atorvastatin 4 Grey-brown hyperpigmented patches Bilateral legs Trunk None Photoprotection Ongoing 15 64 y/o Asian female IV Stage IV NSCLC Osimertinib None 3 Gray-brown hyperpigmentation Abdomen Bilateral arms Back Bilateral legs Pruritus Triamcinolone 0.1% cream; No change, minimal concern to patient Ongoing 16 52 y/o Asian female IV Stage IV NSCLC Osimertinib None 42 Gray hyperpigmented patches with digitate shape Abdomen Bilateral flanks None Triamcinolone 0.1% cream Ongoing NSCLC, non-small cell lung cancer, TMP-SMX, Trimethoprim/Sulfamethoxazole CONCLUSIONS: We highlight the largest case series describing EDP from EGFR inhibitors, which mostly affected Asian patients with lung malignancy and on EGFR tyrosine kinase inhibitors. Clinicians should be able to recognize this condition in their patients and assess how it is affecting their quality of life, and refer to dermatology to help with management.
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Carcinoma Pulmonar de Células não Pequenas , Receptores ErbB , Neoplasias Pulmonares , Humanos , Masculino , Feminino , Idoso , Estudos Retrospectivos , Receptores ErbB/antagonistas & inibidores , Neoplasias Pulmonares/tratamento farmacológico , Pessoa de Meia-Idade , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Eritema/induzido quimicamente , Eritema/etiologia , Acrilamidas/efeitos adversos , Acrilamidas/administração & dosagem , Toxidermias/etiologia , Idoso de 80 Anos ou mais , Antineoplásicos/efeitos adversos , Antineoplásicos/administração & dosagem , Inibidores de Proteínas Quinases/efeitos adversos , Inibidores de Proteínas Quinases/administração & dosagem , Qualidade de VidaRESUMO
BACKGROUND: Reddit is one of the world's most popular social media platforms and is increasingly used as a health information resource for patients on topics such as red-light (RL) therapy. OBJECTIVE: In this article, the authors present an analysis of prevalent patient questions and concerns regarding RL therapy. METHODS: All posts on the "Hot" page of the r/redlighttherapy subreddit were analyzed and categorized. RESULTS: A total of 930 questions from 664 posts were analyzed. The most commonly asked question category was related to product recommendations or feedback (29.7%), followed by usage instructions (15.3%), safety and side effects (12.6%), and indications and efficacy (12.3%). CONCLUSION: Understanding patient concerns and questions about RL, as expressed on online platforms like Reddit, can help clinicians improve patient satisfaction, education, and clinical outcomes. The study offers an innovative approach by using social media to uncover valuable patient insights that might not be easily observable within clinical settings.
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Mídias Sociais , Humanos , Fototerapia/métodos , Satisfação do Paciente , Dermatologia/métodosRESUMO
Sunscreen is an essential way to protect against photodamage from ultraviolet (UV) radiation. Despite the recognized benefits of sunscreen in preventing skin damage from UV light, its use varies across different patient groups. This cross-sectional, questionnaire-based study aims to uncover the sunscreen usage patterns, preferences, and barriers among non-Hispanic White (NHW) and skin of color (SOC) individuals. Our findings demonstrate that NHW individuals are more likely to wear sunscreen daily (31% NHW vs 25% SOC) and reapply sunscreen at least once a day (76% NHW vs 45% SOC) compared with SOC individuals. SOC individuals demonstrate a willingness to use sunscreen, but they face barriers such as cost (2% NHW vs 16% SOC), lack of knowledge in finding suitable products (22% NHW vs 41% SOC), and concerns about white cast (7% NHW vs 25% SOC). SOC individuals are less likely to know the difference between mineral and chemical sunscreen (49% NHW vs 29% SOC), less likely to learn about sunscreen from dermatologists (36% NHW vs 22% SOC), and more likely to prefer sunscreen from brands owned by people of color (13% NHW vs 47% SOC). In addition to analyzing the broader categories of NHW and SOC, subgroup analysis was conducted on specific subgroups, including Black, Asian, and Hispanic groups. Herein, we highlight differences in motivations, sunscreen preferences, sources of information, and knowledge levels about sun protection between NHW and SOC individuals. By uncovering the unique needs and challenges faced by SOC individuals, we aim to improve culturally competent patient education and promote effective sun protection practices across diverse populations. J Drugs Dermatol. 2024;23(6):456-462. doi:10.36849/JDD.8268.
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Conhecimentos, Atitudes e Prática em Saúde , Preferência do Paciente , Protetores Solares , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Estudos Transversais , Queimadura Solar/prevenção & controle , Protetores Solares/administração & dosagem , Inquéritos e Questionários , Raios Ultravioleta/efeitos adversos , Brancos , Negro ou Afro-Americano , Asiático , Hispânico ou LatinoRESUMO
BACKGROUND: Facial rejuvenation by lasers that target water has been a mainstay of esthetic laser treatments for decades. Modern lasers more commonly treat a fraction of the skin surface using ablative, semi-ablative, or nonablative pulses. METHODS: Twenty subjects with visible evidence of chronic photoaging on the face were enrolled in this study. All subjects received two full-face, single-pass treatments spaced 2 months apart with the superficial mode of a 2910 nm fiber laser with an estimated penetration depth of 10 µm, 25% coverage, delivered in a 15 mm × 15 mm square microbeam pattern. A blinded comparison of pretreatment and 3-month post-treatment images was performed. Evaluation of biopsy samples for laser-tissue effects was performed on three separate subjects and biopsies were harvested 1-day post-treatment, 1-week post-treatment, and 2-weeks post-treatment. RESULTS: Blinded evaluation of digital images revealed an average improvement score of 25.1 ± 14.5 (mean ± SEM) or 25.1%, using an 11-point scale evaluating overall improvement in photoaging (p < 0.001). Post-treatment effects were limited to mild-to-moderate erythema and edema, and the pain was rated a 1.9 out of a maximum of 10. Histology demonstrated superficial changes in the stratum corneum and epidermis with dermal inflammation present at 1-day post-treatment and 1-week post-treatment, with a return to baseline at 2 weeks. CONCLUSIONS: The 2910 nm fiber laser is safe and effective for improving mild photodamage, with minimal discomfort and downtime. Dermal inflammation results from very superficial epidermal injury and may contribute to clinical improvement.
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Terapia a Laser , Lasers de Estado Sólido , Envelhecimento da Pele , Humanos , Satisfação do Paciente , Face , Estudos Prospectivos , Rejuvenescimento , Lasers de Estado Sólido/uso terapêutico , Inflamação , Resultado do Tratamento , Terapia a Laser/métodosRESUMO
Ehrlichia chaffeensis (E. chaffeensis) exploits evolutionarily conserved Notch and Wnt host cell signaling pathways to downregulate innate immune host defenses and promote infection. The multifunctional E. chaffeensis TRP120 effector which has HECT E3 ubiquitin ligase activity, interacts with the host nuclear tumor suppressor F-BOX and WD domain repeating-containing 7 (FBW7). FBW7 is the substrate recognition subunit of the Skp1-cullin-1-FBOX E3 ubiquitin (Ub) ligase complex (SCF) known to negatively regulate a network of oncoproteins (Notch, cyclin E, c-Jun, MCL1 and cMYC). In this study, we demonstrate that TRP120 and FBW7 colocalize strongly in the nucleus by confocal immunofluorescent microscopy and interactions between TRP120 and FBW7 FBOX and WD40 domains were demonstrated by ectopic expression and co-immunoprecipitation. Although FBW7 gene expression increased during E. chaffeensis infection, FBW7 levels significantly decreased (>70%) by 72 h post infection. Moreover, an iRNA knockdown of FBW7 coincided with increased E. chaffeensis infection and levels of Notch intracellular domain (NICD), phosphorylated c-Jun, MCL-1 and cMYC, which are negatively regulated by FBW7. An increase in FBW7 K48 ubiquitination was detected during infection by co-IP, and FBW7 degradation was inhibited in infected cells treated with the proteasomal inhibitor bortezomib. Direct TRP120 ubiquitination of native and recombinant FBW7 was demonstrated in vitro and confirmed by ectopic expression of TRP120 HECT Ub ligase catalytic site mutant. This study identifies the tumor suppressor, FBW7, as a TRP120 HECT E3 Ub ligase substrate, and demonstrates that TRP120 ligase activity promotes ehrlichial infection by degrading FBW7 to maintain stability of Notch and other oncoproteins involved in cell survival and apoptosis.
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Ehrlichia chaffeensis/metabolismo , Ehrlichiose/genética , Proteína 7 com Repetições F-Box-WD/metabolismo , Apoptose/fisiologia , Proteínas de Bactérias/metabolismo , Proteínas de Ciclo Celular/metabolismo , Ehrlichia chaffeensis/genética , Ehrlichia chaffeensis/fisiologia , Ehrlichiose/metabolismo , Proteínas F-Box/metabolismo , Proteína 7 com Repetições F-Box-WD/genética , Interações Hospedeiro-Patógeno , Humanos , Proteínas Oncogênicas/genética , Ligação Proteica/fisiologia , Células THP-1 , Ubiquitina-Proteína Ligases/metabolismo , UbiquitinaçãoRESUMO
BACKGROUND: Pityriasis lichenoides (PL) is a papulosquamous disease that affects both adults and children. Previous studies have shown a subset of this entity to have clonal T-cell populations via PCR-based assays. In this study, we sought to implement next-generation sequencing (NGS) as a more sensitive and specific test to examine for T-cell clonality within the pediatric population. METHODS: We identified 18 biopsy specimens from 12 pediatric patients with clinical and histopathologic findings compatible with PL. Patient demographics, clinical features, management, and histopathologic findings were reviewed. All specimens were analyzed for clonality with NGS of T-cell receptor beta (TRB) and gamma (TRG) genes. RESULTS: Of the 12 patients, 9 (75%) had complete resolution of lesions at the time of data collection (mean follow-up 31 months). The remaining three patients significantly improved with methotrexate (with or without acitretin). Interestingly, 7 of 12 patients (58%) and 9 of 17 biopsy specimens (53%) showed evidence of T-cell clonality. Two patients showed matching TRB clones from different anatomic sites. CONCLUSIONS: T-cell clonality is a common finding in PL, probably representing a "reactive clonality" rather than a true lymphoproliferative disorder. Clonality alone cannot be used as a means to distinguish PL from lymphomatoid papulosis or cutaneous lymphoma.
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Clonagem Molecular , Genes Codificadores da Cadeia beta de Receptores de Linfócitos T/genética , Genes Codificadores da Cadeia gama de Receptores de Linfócitos T/genética , Pitiríase Liquenoide/genética , Adolescente , Criança , Pré-Escolar , Feminino , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , MasculinoRESUMO
BACKGROUND AND OBJECTIVES: Treatment of vascular lesions is one of the main applications of cutaneous laser technology, while the other is laser hair removal. We present here a vascular laser pumped by a commercial hair removal laser. STUDY DESIGN/MATERIALS AND METHODS: A novel 524 nm vascular laser was designed using a 755 nm hair removal laser as a pumping source. This 524 nm vascular laser was used to treat facial redness and leg telangiectasias in 24 subjects. Four treatments were administered to the face at 4-6-week intervals and final photographs were taken 8 weeks following the final treatment, while two treatments were administered to lower-extremity spider veins at 2-month intervals with follow-up photographs 3 months following the final treatment. Blinded analysis of digital images was performed by two physicians not involved in the study. RESULTS: Blinded evaluation of digital photographs revealed an average improvement score of 3.3 ± 1.7 (mean ± SEM) on a 0-10 scale for removing facial redness (p < 0.001), representing a 33% improvement. Leg veins improved an average of 51% corresponding to a score of 5.1 ± 2.0 (p < 0.001). Side effects were mild and limited to erythema, purpura, edema, and one instance of mild hyperpigmentation. CONCLUSIONS: This novel 524 nm laser is safe and effective for treating vascularity on the face and legs, and proves the ability to create a laser platform incorporating a hair removal laser which then can be used as a pumping source for the attached vascular laser module.
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Remoção de Cabelo , Terapia a Laser , Telangiectasia , Eritema/etiologia , Humanos , Lasers , Perna (Membro) , Telangiectasia/cirurgia , Resultado do TratamentoRESUMO
Historically recognized by their characteristic histopathologic features, Spitz neoplasms are now known to be molecularly defined by mutually exclusive recurrent abnormalities that cause activation of the MAPK pathway. Spitz neoplasms with ALK rearrangements frequently demonstrate polypoid growth with a plexiform arrangement of nested, fusiform melanocytes in intersecting fascicles. Although neurotropism has been described in indolent Spitz neoplasms, this feature is not frequently mentioned in publications on histopathologic assessment of this group of melanocytic tumors. Here, we present an unusual case of a 3-year-old female with an ALK-positive compound Spitz nevus with extensive perineural and intraneural neurotropism occurring on the vermilion border of the lower lip.
Assuntos
Quinase do Linfoma Anaplásico/genética , Nevo de Células Epitelioides e Fusiformes/patologia , Neoplasias Cutâneas/patologia , Pré-Escolar , Feminino , Humanos , Lábio/patologia , Mutação , Nevo de Células Epitelioides e Fusiformes/genética , Nervos Periféricos/patologia , Neoplasias Cutâneas/genéticaRESUMO
Cutaneous tuberculosis is an uncommon entity with several clinical forms recognized. Histopathologically, most cases are characterized by granulomatous inflammation and caseating necrosis, although less common findings, including vasculitis, have also been described. We report a 55-year-old male with a history of recently diagnosed dermatomyositis receiving immunosuppression with mycophenolate mofetil and prednisone, who developed multifocal soft tissue abscesses and an indurated erythematous plaque on the back. Skin biopsy of the back revealed a necrotizing medium-vessel vasculitis. Mycobacterium tuberculosis was detected in the skin via acid-fast bacilli stain and confirmed by tissue culture and polymerase chain reaction. Cutaneous findings improved rapidly with antituberculosis therapy. This case illustrates an uncommon clinical and histopathologic presentation of disseminated tuberculosis.
Assuntos
Dermatomiosite/complicações , Pele/microbiologia , Infecções dos Tecidos Moles/patologia , Tuberculose Cutânea/diagnóstico , Vasculite/patologia , Abscesso/diagnóstico , Antituberculosos/uso terapêutico , Biópsia , Dermatomiosite/tratamento farmacológico , Diagnóstico Diferencial , Seguimentos , Humanos , Hospedeiro Imunocomprometido , Terapia de Imunossupressão/efeitos adversos , Masculino , Pessoa de Meia-Idade , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/isolamento & purificação , Pele/patologia , Infecções dos Tecidos Moles/diagnóstico , Infecções dos Tecidos Moles/microbiologia , Resultado do Tratamento , Tuberculose Cutânea/tratamento farmacológico , Tuberculose Cutânea/patologiaRESUMO
BACKGROUND: PRAME (PReferentially expressed Antigen in MElanoma) has shown utility in distinguishing melanoma from benign melanocytic lesions, but knowledge of its expression pattern in intermediate melanocytic and spitzoid proliferations is limited. METHODS: Immunohistochemical expression of PRAME was examined in 112 melanocytic proliferations with intermediate histopathologic or spitzoid features. RESULTS: Any intensity of nuclear PRAME staining in at least 60% of lesional melanocytes was determined as the best threshold for diffuse staining in this cohort. Nearly all non-spitzoid melanomas (23/24; 95.8%) demonstrated diffuse PRAME expression. PRAME was completely negative in 95.6% (43/45) of mitotically-active nevi, traumatized nevi, nevi with persistent/recurrent features, and dysplastic nevi. Most Spitz nevi (15/20) and atypical Spitz tumors (10/13) entirely lacked PRAME expression. One Spitz nevus, one atypical Spitz tumor, and one spitzoid melanoma (1/2) demonstrated diffuse PRAME expression. CONCLUSIONS: Although diffuse PRAME expression is generally limited to malignant melanoma, benign Spitz nevi and atypical Spitz tumors can infrequently express diffuse PRAME. PRAME immunohistochemistry can be useful in the evaluation of atypical melanocytic proliferations with intermediate histopathologic features but should be interpreted with caution in the setting of spitzoid neoplasms.
Assuntos
Antígenos de Neoplasias/genética , Proliferação de Células/genética , Melanócitos/patologia , Melanoma/genética , Neoplasias Cutâneas/genética , Adulto , Idoso , Proteínas de Transporte/genética , Estudos de Coortes , Diagnóstico Diferencial , Síndrome do Nevo Displásico/genética , Síndrome do Nevo Displásico/patologia , Feminino , Humanos , Imuno-Histoquímica/métodos , Masculino , Melanoma/patologia , Nevo de Células Epitelioides e Fusiformes/genética , Nevo de Células Epitelioides e Fusiformes/patologia , Neoplasias Cutâneas/patologia , Proteínas Supressoras de Tumor/genética , Ubiquitina Tiolesterase/genética , Melanoma Maligno CutâneoRESUMO
Chagas disease, a multisystem infection caused by the protozoan Trypanosoma cruzi, is primarily found in Latin America. In recent years, prevalence has increased in the United States, where reactivation is the most common clinical scenario. Here, we describe cutaneous reactivation of T. cruzi in a patient with limited cutaneous systemic sclerosis on immunosuppression therapy who simultaneously presented with cytomegalovirus reactivation. Histopathology showed parasitized histiocytes in the superficial and deep dermis. Occasional epidermal keratinocytes were also parasitized, and rare organisms were also seen in the walls of blood vessels. Also noted were viral cytopathic changes within the vascular endothelium, and immunostaining confirmed cytomegalovirus. In this report, we describe the difference in cutaneous findings between reactivated and acute Chagas disease, and we also review the histopathologic features that help distinguish T.cruzi from other intracellular organisms.
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This JAMA Patient Page describes melanoma, its risk factors, diagnosis, treatment, and prognosis.
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Melanoma , Neoplasias Cutâneas , Humanos , Melanoma/diagnóstico , Melanoma/terapia , Prognóstico , Neoplasias Cutâneas/diagnóstico , SíndromeRESUMO
Peroxisome proliferator-activated receptor γ (PPARγ) ligands have been widely used to treat type 2 diabetes mellitus. However, knowledge of PPARγ signaling remains incomplete. In addition to PPARγ, these drugs also activate G protein-coupled receptor 40 (GPR40), a Gαq-coupled free fatty acid receptor linked to MAPK networks and glucose homeostasis. Notably, p38 MAPK activation has been implicated in PPARγ signaling. Here, rosiglitazone (RGZ) activation of GPR40 and p38 MAPK was found to boost PPARγ-induced gene transcription in human endothelium. Inhibition or knockdown of p38 MAPK or expression of a dominant negative (DN) p38 MAPK mutant blunted RGZ-induced PPARγ DNA binding and reporter activity in EA.hy926 human endothelial cells. GPR40 inhibition or knockdown, or expression of a DN-Gαq mutant likewise blocked activation of both p38 MAPK and PPARγ reporters. Importantly, RGZ induction of PPARγ target genes in primary human pulmonary artery endothelial cells (PAECs) was suppressed by knockdown of either p38 MAPK or GPR40. GPR40/PPARγ signal transduction was dependent on p38 MAPK activation and induction of PPARγ co-activator-1 (PGC1α). Silencing of p38 MAPK or GPR40 abolished the ability of RGZ to induce phosphorylation and expression of PGC1α in PAECs. Knockdown of PGC1α, its essential activator SIRT1, or its binding partner/co-activator EP300 inhibited RGZ induction of PPARγ-regulated genes in PAECs. RGZ/GPR40/p38 MAPK signaling also led to EP300 phosphorylation, an event that enhances PPARγ target gene transcription. Thus, GPR40 and PPARγ can function as an integrated two-receptor signal transduction pathway, a finding with implications for rational drug development.