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Bax MJ, Brown MD, Rothberg PG, Laughlin TS, Scott GA. Pigmented epithelioid melanocytoma (animal-type melanoma): An institutional experience. J Am Acad Dermatol 2017; 77:328-332. [DOI: 10.1016/j.jaad.2017.01.029] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 01/13/2017] [Accepted: 01/17/2017] [Indexed: 11/16/2022]
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Yan G, Eller MS, Elm C, Larocca CA, Ryu B, Panova IP, Dancy BM, Bowers EM, Meyers D, Lareau L, Cole PA, Taverna SD, Alani RM. Selective inhibition of p300 HAT blocks cell cycle progression, induces cellular senescence, and inhibits the DNA damage response in melanoma cells. J Invest Dermatol 2013; 133:2444-2452. [PMID: 23698071 PMCID: PMC4380234 DOI: 10.1038/jid.2013.187] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Revised: 03/08/2013] [Accepted: 03/21/2013] [Indexed: 01/04/2023]
Abstract
Epigenetic events, including covalent post-translational modifications of histones, have been demonstrated to have critical roles in tumor development and progression. The transcriptional coactivator p300/CBP possesses both histone acetyltransferase (HAT) activity and scaffolding properties that directly influence the transcriptional activation of targeted genes. We have used a potent and specific inhibitor of p300/CBP HAT activity, C646, in order to evaluate the functional contributions of p300/CBP HAT to tumor development and progression. Here we report that C646 inhibits the growth of human melanoma and other tumor cells and promotes cellular senescence. Global assessment of the p300 HAT transcriptome in human melanoma identified functional roles in promoting cell cycle progression, chromatin assembly, and activation of DNA repair pathways through direct transcriptional regulatory mechanisms. In addition, C646 is shown to promote sensitivity to DNA damaging agents, leading to the enhanced apoptosis of melanoma cells after combination treatment with cisplatin. Together, our data suggest that p300 HAT activity mediates critical growth regulatory pathways in tumor cells and may serve as a potential therapeutic target for melanoma and other malignancies by promoting cellular responses to DNA damaging agents that are currently ineffective against specific cancers.
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Affiliation(s)
- Gai Yan
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Mark S Eller
- Department of Dermatology, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Courtney Elm
- Department of Dermatology, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Cecilia A Larocca
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Byungwoo Ryu
- Department of Dermatology, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Izabela P Panova
- Department of Dermatology, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Beverley M Dancy
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Erin M Bowers
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - David Meyers
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Lisa Lareau
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Philip A Cole
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
| | - Sean D Taverna
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
| | - Rhoda M Alani
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA; Department of Dermatology, Boston University School of Medicine, Boston, Massachusetts, USA; Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
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Koenig A, Bianco SR, Fosmire S, Wojcieszyn J, Modiano JF. Expression and significance of p53, rb, p21/waf-1, p16/ink-4a, and PTEN tumor suppressors in canine melanoma. Vet Pathol 2002; 39:458-72. [PMID: 12126149 DOI: 10.1354/vp.39-4-458] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The role of tumor suppressor genes in the pathogenesis of canine melanoma is incompletely understood. The genes encoding the tumor suppressors p53, Rb, p21 (waf-1), p16 (ink-4a), and PTEN have been postulated to contribute to the pathogenesis of melanoma in humans and experimental animal models. To assess whether inactivation of these genes similarly contributes to the origin and progression of canine melanoma, we examined their expression in seven distinct canine melanoma cell lines and in 31 retrospective samples (representing 29 dogs) of spontaneous canine melanoma. Various patterns suggestive of loss of tumor suppressor function emerged in these cell lines. The most frequently observed abnormality was loss or significant reduction of p16 expression in six of seven cell lines and in 21 of 26 tumor samples. Loss or significant reduction of PTEN expression was seen in four of seven cell lines and in 13 of 27 tumor samples. Although p53 was detectable in all the cell lines and in 24 of 30 tumors, exclusion of p53 from the nuclear compartment was observed in each of the cell lines and in 18 of 25 tumor samples. These results indicate that loss of function of these tumor suppressor proteins is a common occurrence that may contribute to the origin of canine melanoma. In our sample population, abnormalities in the expression or localization of one or more tumor suppressor proteins occurred with similar frequency in malignant and benign tumors; thus, additional work is necessary to determine how these proteins may impact disease progression and response to therapy.
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Affiliation(s)
- A Koenig
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, Texas A & M University, College Station, USA
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Modiano JF, Ritt MG, Wojcieszyn J, Smith R. Growth arrest of melanoma cells is differentially regulated by contact inhibition and serum deprivation. DNA Cell Biol 1999; 18:357-67. [PMID: 10360837 DOI: 10.1089/104454999315259] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Both growth-factor deprivation and contact inhibition suppress cell growth; however, the mechanisms by which they inhibit cell proliferation may not be identical. The function of antiproliferative genes and the induction of programmed cell death are among the potential differences between these growth-arrest mechanisms. Specifically, an inverse relation between the expression of cyclin-dependent kinase inhibitors (CDKIs) and the susceptibility to apoptosis has been reported. To test this relation, we examined the features of growth arrest in a canine melanoma cell line, TLM1. Both contact inhibition and serum deprivation halted cell-cycle progression of TLM1 cells in the G1 phase. Prolonged growth arrest of the cells without restimulation resulted in apoptosis; conversely, the cells reentered the cell cycle after release from contact inhibition or on restimulation with serum. Cell-to-cell contact, but not serum deprivation, led to the expression of p53 and p21/Waf-1. The expression of p21/Waf-1 did not prevent apoptosis. Moreover, the ectopic overexpression of CDKIs increased apoptosis. These results support the premise that growth arrest induced by contact inhibition and serum deprivation are mediated through distinct mechanisms. Furthermore, CDKIs are not universal inhibitors of apoptosis, and in some cases, they may initiate or enhance the apoptotic program.
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Affiliation(s)
- J F Modiano
- Department of Pathobiology, Texas A&M University, College Station 77843-4467, USA
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Weiss J, Heine M, Körner B, Pilch H, Jung EG. Expression of p53 protein in malignant melanoma: clinicopathological and prognostic implications. Br J Dermatol 1995; 133:23-31. [PMID: 7669636 DOI: 10.1111/j.1365-2133.1995.tb02487.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In the present study, we investigated the expression of the tumour suppressor protein p53 in 113 primary and 43 metastatic malignant melanomas by immunohistochemistry, and correlated the findings with clinicopathological parameters such as histological melanoma subtype, thickness of primary melanomas (Breslow thickness) and patient outcome. In primary melanomas, the polyclonal anti-p53 antibody CM-1 detected immunoreactivity in 70% of the lesions, predominantly in the cytoplasm. Signals were observed in this cellular compartment in 57% of the melanomas, whereas in 32% nuclear p53 over-expression was detected. Immunohistochemistry, using the monoclonal antibody DO-1, revealed lower staining frequencies. However, both antibodies showed congruent results in approximately 80% of the cases. Overall, immunoreactivity was observed in 73% of superficial spreading melanomas, but only in 52% of lentigo maligna melanomas. This difference (P < 0.001) was mainly due to a lower frequency of cytoplasmic immunoreactivity (P < 0.002). There was no difference with respect to cytoplasmic and nuclear immunoreactivity between thin (< 1 mm thickness) and thicker primary melanomas. Staining frequencies detected in metastatic lesions seemed to be lower than in primary tumours. In 103 primary melanomas, follow-up data for at least 5 years were available. In 71% (54 of 76) of the primary melanomas which did not recur, and in 78% (21 of 27) of tumours with subsequent metastases, p53 over-expression was detected by CM-1. However, this difference was not statistically significant. The results of the present study indicate that immunoreactivity to anti-p53 antibodies is a common observation in malignant melanomas, with staining signals predominantly found in the cytoplasm of cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J Weiss
- Department of Dermatology, Mannheim Medical School, Germany
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Weiss J, Heine M, Arden KC, Körner B, Pilch H, Herbst RA, Jung EG. Mutation and expression of TP53 in malignant melanomas. Recent Results Cancer Res 1995; 139:137-154. [PMID: 7597286 DOI: 10.1007/978-3-642-78771-3_10] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Mutations of the TP53 gene are the most common genetic alterations in human malignancies. Overexpression of the p53 protein has been reported in high frequencies in all types of skin cancer. To determine the role of TP53 in the pathogenesis of malignant melanoma, we investigated the expression of p53 in 12 cell lines and 145 primary and metastatic lesions by immunohistochemistry. Overexpression of p53 was predominantly detected in the cytoplasm of the cells in 96 (66%) tumor and 12 (93%) cell lines. In contrast to findings in other tumor types, in melanomas immunoreactive cells were found in clusters or as scattered single cells. In primary melanomas, the frequency of p53 overexpression did not correlate with tumor thickness. Nucleotide sequencing of TP53 genes of 24 melanoma tumors/cell lines demonstrated point mutations in seven samples, all coding for mutant p53 protein species. The frequency of TP53 alterations of 20%-30% is lower than in other skin tumor types. Notably, immunohistochemistry was not a suitable method to distinguish overexpression of wild-type p53 from mutant species, since cell lines/tumors with TP53 mutations did not show distinctive staining patterns. The mutation pattern in six out of seven lesions was similar to that caused by ultraviolet light damage. This finding may be regarded a further indication for a pathogenetic role of UV light damage in at least a subgroup of malignant melanomas.
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MESH Headings
- Antibodies, Monoclonal/immunology
- Carcinoma, Basal Cell/genetics
- Carcinoma, Basal Cell/metabolism
- Carcinoma, Squamous Cell/genetics
- Carcinoma, Squamous Cell/metabolism
- Cytoplasm/chemistry
- DNA Mutational Analysis
- DNA, Neoplasm/genetics
- Fluorescent Antibody Technique
- Gene Expression Regulation, Neoplastic
- Genes, p53
- Humans
- Melanoma/genetics
- Melanoma/metabolism
- Melanoma/pathology
- Neoplasm Metastasis
- Neoplasm Proteins/analysis
- Neoplasm Proteins/biosynthesis
- Neoplasm Proteins/genetics
- Neoplasm Proteins/immunology
- Neoplasms, Radiation-Induced/genetics
- Neoplasms, Radiation-Induced/metabolism
- Neoplasms, Radiation-Induced/pathology
- Point Mutation
- Skin Neoplasms/genetics
- Skin Neoplasms/metabolism
- Skin Neoplasms/pathology
- Tumor Cells, Cultured
- Tumor Suppressor Protein p53/analysis
- Tumor Suppressor Protein p53/biosynthesis
- Tumor Suppressor Protein p53/immunology
- Ultraviolet Rays/adverse effects
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Affiliation(s)
- J Weiss
- Department of Dermatology, University of Heidelberg, Mannheim, Germany
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