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Asato MA, Moares Neto FA, Moraes MPDT, Ocanha-Xavier JP, Takita LC, Marques MEA, Xavier-Júnior JCC. Proposal for the applicability of modified Breslow (measured from the basal membrane) as a predictor of survival and sentinel lymph node outcome in patients with cutaneous melanoma. An Bras Dermatol 2024; 99:398-406. [PMID: 38378363 DOI: 10.1016/j.abd.2023.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 09/05/2023] [Accepted: 09/08/2023] [Indexed: 02/22/2024] Open
Abstract
BACKGROUND Cutaneous melanoma is a neoplasm with a high mortality rate and risk of metastases to distant organs. The Breslow micrometric measurement is considered the most important factor for evaluating prognosis and management, measured from the granular layer to the deepest portion of the neoplasm. Despite its widespread use, the Breslow thickness measurement has some inaccuracies, such as not considering variations in the thickness of the epidermis in different body locations or when there is ulceration. OBJECTIVE To evaluate the applicability of a modified Breslow measurement, measured from the basal membrane instead of from the granular layer, in an attempt to predict sentinel lymph node examination outcome and survival of patients with melanoma. METHODS A retrospective and cross-sectional analysis was carried out based on the evaluation of slides stained with hematoxylin & eosin from 275 cases of melanoma that underwent sentinel lymph node biopsy from 2008 to 2021 at a reference center in Brazil. RESULTS Analysis of the Cox model to evaluate the impact of the Breslow measurement and the modified Breslow measurement on survival showed that both methods are statistically significant. Logistic regression revealed a significant association between both measurements and the presence of metastasis in sentinel lymph nodes. CONCLUSION Measuring melanoma depth from the basal membrane (modified Breslow measurement) is capable of predicting survival time and sentinel lymph node outcome, as well as the conventional Breslow measurement.
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Affiliation(s)
- Marcel Arakaki Asato
- Faculty of Medicine, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS, Brazil; Department of Pathology, Faculty of Medicine, Universidade Estadual Paulista, Botucatu, SP, Brazil
| | | | | | | | - Luiz Carlos Takita
- Faculty of Medicine, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS, Brazil
| | | | - José Cândido Caldeira Xavier-Júnior
- Department of Pathology, Faculty of Medicine, Universidade Estadual Paulista, Botucatu, SP, Brazil; Faculty of Medicine, Centro Universitário Unisalesiano Auxilium, Araçatuba, SP, Brazil; Department of Dermatopathology, Instituto de Patologia de Araçatuba, Araçatuba, SP, Brazil.
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Flont M, Dybko A, Jastrzębska E. A layered cancer-on-a-chip system for anticancer drug screening and disease modeling. Analyst 2023; 148:5486-5495. [PMID: 37768020 DOI: 10.1039/d3an00959a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/29/2023]
Abstract
Recent advances in the development of microfluidic systems for the culture of complex and three-dimensional cell, tissue, and organ models allow their use in toxicity studies and mimicking many diseases. These types of in vitro models are important because of the huge advantages over standard two-dimensional cell cultures: better mimicking of in vivo conditions and more reliable response to the tested drugs. This report presents a new approach to modeling skin cancer (melanoma-on-a-chip) and breast cancer (breast cancer-on-a-chip) using the microfluidic systems. We designed a microfluidic device to co-culture cancer cells with non-malignant cells, which are the main component of the cancer microenvironment. In the construction of the microsystem, we used a scaffold in the form of a porous membrane made of poly(ethylene terephthalate), which enables the regular and reproducible arrangement of cells in the culture and maintains intercellular communication. To demonstrate the functionality of the microsystem, we used it to analyze the effectiveness of photodynamic therapy in the treatment of melanoma and chemotherapy in the treatment of breast cancer. The developed microsystem can be successfully used to model cancer diseases, especially with a layered arrangement of cells in the cancerous tissue, such as melanoma, ductal breast cancer, or breast cancer metastases to the skin.
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Affiliation(s)
- Magdalena Flont
- Center for Advanced Materials and Technologies CEZAMAT, Warsaw University of Technology, Poleczki 19, 02-822 Warsaw, Poland.
| | - Artur Dybko
- Chair of Medical Biotechnology, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Elżbieta Jastrzębska
- Center for Advanced Materials and Technologies CEZAMAT, Warsaw University of Technology, Poleczki 19, 02-822 Warsaw, Poland.
- Chair of Medical Biotechnology, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
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Ottaiano A, Santorsola M, Perri F, Pace U, Marra B, Correra M, Sabbatino F, Cascella M, Petrillo N, Ianniello M, Casillo M, Misso G, Delrio P, Caraglia M, Nasti G. Clinical and Molecular Characteristics of Rare Malignant Tumors of Colon and Rectum. BIOLOGY 2022; 11:biology11020267. [PMID: 35205133 PMCID: PMC8869306 DOI: 10.3390/biology11020267] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 01/21/2022] [Accepted: 02/05/2022] [Indexed: 02/04/2023]
Abstract
Simple Summary Tumors of colon and rectum other than adenocarcinomas represent a neglected issue from clinical and laboratory points of view because of their rarity. In this review, we summarize and describe the rare histologic entities occurring in colon and rectum. Clinical and pathologic characteristics, prognostic behavior, treatments, and altered genes are reported to provide readers with a paramount and comparative perspective. In relation to this, we propose that improvements in registries and multidisciplinary research are warranted to ameliorate their management. Abstract The most frequent form of colorectal cancer is represented by adenocarcinoma being about 98% of tumor histological types. However, other rare histotypes can be found in colon and rectum (adenosquamous, goblet cell adenocarcinoma, lymphoma, medullary carcinoma, melanoma, mesenchymal, neuroendocrine, plasmacytoma, signet ring, squamous tumors). Altogether, these forms account for less than 2% of colorectal tumors. There are no specific diagnostic or therapeutic recommended approaches and most of the information available from literature derives from small and retrospective clinical series. In the present study, we provide a paramount and updated view on clinical and biologic characteristics of rare colorectal tumors.
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Affiliation(s)
- Alessandro Ottaiano
- Istituto Nazionale Tumori di Napoli, IRCCS “G. Pascale”, Via M. Semmola, 80131 Naples, Italy; (M.S.); (F.P.); (U.P.); (B.M.); (M.C.); (M.C.); (P.D.); (G.N.)
- Correspondence:
| | - Mariachiara Santorsola
- Istituto Nazionale Tumori di Napoli, IRCCS “G. Pascale”, Via M. Semmola, 80131 Naples, Italy; (M.S.); (F.P.); (U.P.); (B.M.); (M.C.); (M.C.); (P.D.); (G.N.)
| | - Francesco Perri
- Istituto Nazionale Tumori di Napoli, IRCCS “G. Pascale”, Via M. Semmola, 80131 Naples, Italy; (M.S.); (F.P.); (U.P.); (B.M.); (M.C.); (M.C.); (P.D.); (G.N.)
| | - Ugo Pace
- Istituto Nazionale Tumori di Napoli, IRCCS “G. Pascale”, Via M. Semmola, 80131 Naples, Italy; (M.S.); (F.P.); (U.P.); (B.M.); (M.C.); (M.C.); (P.D.); (G.N.)
| | - Bruno Marra
- Istituto Nazionale Tumori di Napoli, IRCCS “G. Pascale”, Via M. Semmola, 80131 Naples, Italy; (M.S.); (F.P.); (U.P.); (B.M.); (M.C.); (M.C.); (P.D.); (G.N.)
| | - Marco Correra
- Istituto Nazionale Tumori di Napoli, IRCCS “G. Pascale”, Via M. Semmola, 80131 Naples, Italy; (M.S.); (F.P.); (U.P.); (B.M.); (M.C.); (M.C.); (P.D.); (G.N.)
| | - Francesco Sabbatino
- Oncology Unit, San Giovanni di Dio e Ruggi D’Aragona University Hospital, Universisty of Salerno, 84131 Salerno, Italy;
| | - Marco Cascella
- Istituto Nazionale Tumori di Napoli, IRCCS “G. Pascale”, Via M. Semmola, 80131 Naples, Italy; (M.S.); (F.P.); (U.P.); (B.M.); (M.C.); (M.C.); (P.D.); (G.N.)
| | - Nadia Petrillo
- AMES, Centro Polidiagnostico Strumentale srl, 80013 Naples, Italy; (N.P.); (M.I.); (M.C.)
| | - Monica Ianniello
- AMES, Centro Polidiagnostico Strumentale srl, 80013 Naples, Italy; (N.P.); (M.I.); (M.C.)
| | - Marika Casillo
- AMES, Centro Polidiagnostico Strumentale srl, 80013 Naples, Italy; (N.P.); (M.I.); (M.C.)
| | - Gabriella Misso
- Department of Precision Medicine, University of Campania “L. Vanvitelli”, Via de Crecchio 7, 80138 Naples, Italy; (G.M.); (M.C.)
| | - Paolo Delrio
- Istituto Nazionale Tumori di Napoli, IRCCS “G. Pascale”, Via M. Semmola, 80131 Naples, Italy; (M.S.); (F.P.); (U.P.); (B.M.); (M.C.); (M.C.); (P.D.); (G.N.)
| | - Michele Caraglia
- Department of Precision Medicine, University of Campania “L. Vanvitelli”, Via de Crecchio 7, 80138 Naples, Italy; (G.M.); (M.C.)
| | - Guglielmo Nasti
- Istituto Nazionale Tumori di Napoli, IRCCS “G. Pascale”, Via M. Semmola, 80131 Naples, Italy; (M.S.); (F.P.); (U.P.); (B.M.); (M.C.); (M.C.); (P.D.); (G.N.)
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Weitzenböck HP, Gschwendtner A, Wiesner C, Depke M, Schmidt F, Trautinger F, Hengstschläger M, Hundsberger H, Mikula M. Proteome analysis of NRF2 inhibition in melanoma reveals CD44 up-regulation and increased apoptosis resistance upon vemurafenib treatment. Cancer Med 2021; 11:956-967. [PMID: 34951143 PMCID: PMC8855890 DOI: 10.1002/cam4.4506] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 11/30/2021] [Accepted: 12/04/2021] [Indexed: 12/27/2022] Open
Abstract
Malignant melanoma is the deadliest form of skin cancer and NRF2 has been proposed as a main regulator of tumor cell malignancy. Still the mechanisms how NRF2 is contributing to melanoma progression are incompletely understood. Here we analyzed the effects of either NRF2 induction or depletion, and we also quantified changes on the whole cell proteome level. Our results showed that inhibition of NRF2 leads to a loss of reactive oxygen species protection, but at the same time to an induction of an epithelial mesenchymal transition (EMT) phenotype and an up‐regulation of the stem cell marker CD44. Additionally, cells devoid of NRF2 showed increased cell viability after treatment with a MYC and a BRAF inhibitor. Importantly, survival upon vemurafenib treatment was dependent on CD44 expression. Finally, analysis of archival melanoma patient samples confirmed a vice versa relationship of NRF2 and CD44 expression. In summary, we recorded changes in the proteome after NRF2 modulation in melanoma cells. Surprisingly, we identified that NRF2 inhibition lead to induction of an EMT phenotype and an increase in survival of cells after apoptosis induction. Therefore, we propose that it is important for future therapies targeting NRF2 to consider blocking EMT promoting pathways in order to achieve efficient tumor therapy.
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Affiliation(s)
- Hans Peter Weitzenböck
- Medical and Pharmaceutical Biotechnology, IMC University of Applied Sciences, Krems, Austria
| | - Anna Gschwendtner
- Center for Pathobiochemistry and Genetics, Medical University of Vienna, Vienna, Austria
| | - Christoph Wiesner
- Medical and Pharmaceutical Biotechnology, IMC University of Applied Sciences, Krems, Austria
| | - Maren Depke
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Frank Schmidt
- Proteomics Core, Weill Cornell Medicine-Qatar, Qatar Foundation-Education City, Doha, Qatar
| | - Franz Trautinger
- Department of Dermatology and Venereology, University Hospital of St. Pölten, Karl Landsteiner University of Health Sciences, St. Pölten, Austria.,Karl Landsteiner Institute of Dermatological Research, St. Pölten, Austria
| | - Markus Hengstschläger
- Center for Pathobiochemistry and Genetics, Medical University of Vienna, Vienna, Austria
| | - Harald Hundsberger
- Medical and Pharmaceutical Biotechnology, IMC University of Applied Sciences, Krems, Austria.,Department of Dermatology, University Hospital of the Paracelsus Medical University, Salzburg, Austria
| | - Mario Mikula
- Center for Pathobiochemistry and Genetics, Medical University of Vienna, Vienna, Austria
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Dysfunction of the limbal epithelial stem cell niche in aniridia-associated keratopathy. Ocul Surf 2021; 21:160-173. [PMID: 34102310 DOI: 10.1016/j.jtos.2021.06.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 04/22/2021] [Accepted: 06/01/2021] [Indexed: 02/06/2023]
Abstract
PURPOSE Abnormalities in the limbal niche microenvironment have been suggested to be causally involved in aniridia-associated keratopathy (AAK), but histological analyses on the limbal structure and composition in AAK are lacking. Here, we investigated morphologic and molecular alterations of the limbal epithelial stem cell niche in human congenital aniridia. METHODS The blind, buphthalmic and painful left eye of a 16-year old girl with congenital aniridia and juvenile glaucoma had to be enucleated because of uncontrolled intraocular pressure. The diagnosis of AAK was based on classical clinical features and partial limbal stem cell deficiency in the superior half. Genetic analysis identified a large heterozygous PAX6 gene deletion encompassing exons 11-15 as well as exon 9 of the neighboring ELP4 gene. Three limbal biopsies were taken from the superior, nasal and temporal regions to isolate and cultivate limbal epithelial progenitor cells and subject them to mRNA expression analyses. The globe was vertically bisected and processed for light and transmission electron microscopy and immunohistochemistry. RESULTS Comparative analysis of the superior and inferior limbal zones showed a gradual degradation of palisade structures associated with the transition from a hyperplastic to an attenuated corneal epithelium, inflammatory cell infiltrations and basement membrane irregularities. The clinically unaffected inferior part revealed no distinct stem cell clusters in the preserved palisade region, but a uniform population of hyperproliferative, undifferentiated progenitor cells in the basal/suprabasal layers of limbal and corneal epithelia, which gave rise to maldifferentiated epithelial cells exhibiting a conjunctival/epidermal phenotype and nuclear-to-cytoplasmic translocation of Pax6. The structure of the limbal niche was fundamentally perturbed, showing marked alterations in extracellular matrix composition, dislocation of atypical melanocytes lacking melanosomes and melanin, aberrant Wnt/β-catenin and retinoic acid signaling, and massive immune cell infiltration. CONCLUSIONS Considering the limitations of a single Case study, the findings suggest that ocular surface alterations in AAK are caused by a primary dysfunction and gradual breakdown of the limbal stem cell niche through Pax6-related effects on both melanogenesis and epithelial differentiation.
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Sun LD, Chu X, Xu L, Fan XZ, Qian Y, Zuo DM. Primary intramedullary melanoma of lumbar spinal cord: A case report. World J Clin Cases 2021; 9:2352-2356. [PMID: 33869613 PMCID: PMC8026835 DOI: 10.12998/wjcc.v9.i10.2352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/15/2020] [Accepted: 12/28/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Primary intramedullary melanoma is a very rare tumor, most frequently occurring in the cervical and thoracic spinal cord.
CASE SUMMARY We present a rare case in which the primary intramedullary melanoma was located in the lumbar spine. A 56-year-old man complained of progressive intermittent pain in the lumbar area. Thoracic magnetic resonance imaging showed a spinal intramedullary tumor between the L3 and S1 levels. The tumor was resected entirely, and the diagnosis of malignant melanoma was confirmed by histopathology.
CONCLUSION Primary melanoma of the spinal cord, particularly intramedullary localization, has rarely been reported in the previous literature. We describe a primary malignant melanoma of the lumbar spinal cord and discuss the challenges associated with the diagnosis.
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Affiliation(s)
- Le-Dong Sun
- Department of Dermatology, The Fifth Affiliated Hospital, Southern Medical University, Guangzhou 510900, Guangdong Province, China
| | - Xin Chu
- Department of Dermatology, The Fifth Affiliated Hospital, Southern Medical University, Guangzhou 510900, Guangdong Province, China
| | - Li Xu
- Department of Dermatology, The Fifth Affiliated Hospital, Southern Medical University, Guangzhou 510900, Guangdong Province, China
| | - Xiu-Zhen Fan
- Department of Dermatology, The Fifth Affiliated Hospital, Southern Medical University, Guangzhou 510900, Guangdong Province, China
| | - Yi Qian
- The Fifth Affiliated Hospital, Southern Medical University, Guangzhou 510900, Guangdong Province, China
| | - Da-Ming Zuo
- Department of Medical Laboratory, Southern Medical University, Guangzhou 510515, Guangdong Province, China
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Mitsiogianni M, Kyriakou S, Anestopoulos I, Trafalis DT, Deligiorgi MV, Franco R, Pappa A, Panayiotidis MI. An Evaluation of the Anti-Carcinogenic Response of Major Isothiocyanates in Non-Metastatic and Metastatic Melanoma Cells. Antioxidants (Basel) 2021; 10:antiox10020284. [PMID: 33668498 PMCID: PMC7918923 DOI: 10.3390/antiox10020284] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 02/07/2021] [Accepted: 02/10/2021] [Indexed: 12/28/2022] Open
Abstract
Malignant melanoma is one of the most deadly types of solid cancers, a property mainly attributed to its highly aggressive metastatic form. On the other hand, different classes of isothiocyanates, a class of phytochemicals, present in cruciferous vegetables have been characterized by considerable anti-cancer activity in both in vitro and in vivo experimental models. In the current study, we investigated the anti-cancer response of five isothiocyanates in an in vitro model of melanoma consisting of non-metastatic (A375, B16F-10) and metastatic (VMM1, Hs294T) malignant melanoma as well as non-melanoma epidermoid carcinoma (A431) and non-tumorigenic melanocyte-neighboring keratinocyte (HaCaT) cells. Our aim was to compare different endpoints of cytotoxicity (e.g., reactive oxygen species, intracellular glutathione content, cell cycle growth arrest, apoptosis and necrosis) descriptive of an anti-cancer response between non-metastatic and metastatic melanoma as well as non-melanoma epidermoid carcinoma and non-tumorigenic cells. Our results showed that exposure to isothiocyanates induced an increase in intracellular reactive oxygen species and glutathione contents between non-metastatic and metastatic melanoma cells. The distribution of cell cycle phases followed a similar pattern in a manner where non-metastatic and metastatic melanoma cells appeared to be growth arrested at the G2/M phase while elevated levels of metastatic melanoma cells were shown to be at sub G1 phase, an indicator of necrotic cell death. Finally, metastatic melanoma cells were more sensitive apoptosis and/or necrosis as higher levels were observed compared to non-melanoma epidermoid carcinoma and non-tumorigenic cells. In general, non-melanoma epidermoid carcinoma and non-tumorigenic cells were more resistant under any experimental exposure condition. Overall, our study provides further evidence for the potential development of isothiocyanates as promising anti-cancer agents against non-metastatic and metastatic melanoma cells, a property specific for these cells and not shared by non-melanoma epidermoid carcinoma or non-tumorigenic melanocyte cells.
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Affiliation(s)
- Melina Mitsiogianni
- Department of Applied Sciences, Northumbria University, Newcastle Upon Tyne NE1 8ST, UK;
| | - Sotiris Kyriakou
- Department of Electron Microscopy & Molecular Pathology, The Cyprus Institute of Neurology & Genetics, Nicosia 2371, Cyprus; (S.K.); (I.A.)
- The Cyprus School of Molecular Medicine, P.O. Box 23462, Nicosia 1683, Cyprus
| | - Ioannis Anestopoulos
- Department of Electron Microscopy & Molecular Pathology, The Cyprus Institute of Neurology & Genetics, Nicosia 2371, Cyprus; (S.K.); (I.A.)
- The Cyprus School of Molecular Medicine, P.O. Box 23462, Nicosia 1683, Cyprus
| | - Dimitrios T. Trafalis
- Laboratory of Pharmacology, Medical School, National & Kapodistrian University of Athens, 11527 Athens, Greece; (D.T.T.); (M.V.D.)
| | - Maria V. Deligiorgi
- Laboratory of Pharmacology, Medical School, National & Kapodistrian University of Athens, 11527 Athens, Greece; (D.T.T.); (M.V.D.)
| | - Rodrigo Franco
- Redox Biology Centre, University of Nebraska-Lincoln, Lincoln, NE 68583, USA;
- Department of Veterinary Medicine & Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
| | - Aglaia Pappa
- Department of Molecular Biology & Genetics, Democritus University of Thrace, 68100 Alexandroupolis, Greece;
| | - Mihalis I. Panayiotidis
- Department of Applied Sciences, Northumbria University, Newcastle Upon Tyne NE1 8ST, UK;
- Department of Electron Microscopy & Molecular Pathology, The Cyprus Institute of Neurology & Genetics, Nicosia 2371, Cyprus; (S.K.); (I.A.)
- The Cyprus School of Molecular Medicine, P.O. Box 23462, Nicosia 1683, Cyprus
- Correspondence: ; Tel.: +357-223-92626
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STAT3 promotes melanoma metastasis by CEBP-induced repression of the MITF pathway. Oncogene 2020; 40:1091-1105. [PMID: 33323974 PMCID: PMC7116782 DOI: 10.1038/s41388-020-01584-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 10/30/2020] [Accepted: 11/24/2020] [Indexed: 12/22/2022]
Abstract
Metastatic melanoma is hallmarked by its ability of phenotype switching to more slowly proliferating, but highly invasive cells. Here, we tested the impact of signal transducer and activator of transcription 3 (STAT3) on melanoma progression in association with melanocyte inducing transcription factor (MITF) expression levels. We established a mouse melanoma model for deleting Stat3 in melanocytes with specific expression of human hyperactive NRASQ61K in an Ink4a deficient background, two frequent driver mutations in human melanoma. Mice devoid of Stat3 showed early disease onset with higher proliferation in primary tumors, but displayed significantly diminished lung, brain and liver metastases. Whole genome expression profiling of tumor-derived cells also showed a reduced invasion phenotype, which was further corroborated by 3D melanoma model analysis. Notably, loss or knockdown of STAT3 in mouse or human cells resulted in up-regulation of MITF and induction of cell proliferation. Mechanistically we show that STAT3-induced CEBPa/b expression was sufficient to suppress MITF transcription. Epigenetic analysis by ATAC-seq confirmed that CEBPa/b binding to the MITF enhancer region silenced the MITF locus. Finally, by classification of patient-derived melanoma samples, we show that STAT3 and MITF act antagonistically and hence contribute differentially to melanoma progression. We conclude that STAT3 is a driver of the metastatic process in melanoma and able to antagonize MITF via direct induction of CEBP family member transcription.
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