DNA double-strand breaks are increased in human melanoma tissue as detected by histone H2AX phosphorylation.(1-3) We investigated two of the downstream effectors of DNA double-strand breaks, Rad50 and 53BP1 (tumor suppressor p53 binding protein 1), to determine if they are altered in human primary melanoma cells. Melanoma cases showed high Rad50 staining (81.8%; 9/11) significantly more frequently than conventional or atypical melanocytic nevi (0%; 0/18). In contrast, the staining pattern for 53BP1 appears similar between melanoma and nevi. This is the first study that shows activation and misregulation of the DNA repair pathway in human melanoma cells. The staining features of Rad50, a component of an essential DNA double-strand break repair complex, are clearly increased in melanoma cells with regards to both staining intensity and the number of positive melanoma cells. Interestingly, among the melanoma cases with increased Rad50 staining, most demonstrated cytoplasmic rather than nuclear staining (88.9%, 8/9). Further studies are needed to determine the cause of this mislocalization and its affects, if any, on DNA double-strand break repair in melanoma.
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http://dx.doi.org/10.1111/j.1600-0560.2012.01915.x | DOI Listing |
Front Immunol
January 2025
Centro de Investigaciones Oncológicas (FUCA), Fundación Cáncer, Ciudad Autónoma de Buenos Aires, Argentina.
VACCIMEL is a therapeutic cancer vaccine composed of four irradiated allogeneic human melanoma cell lines rationally selected to cover a wide range of melanoma tumor-associated antigens (TAA). We previously demonstrated that vaccination in the adjuvant setting prolonged the distant-metastasis-free survival of cutaneous melanoma patients and that T cells reactive to TAA and the patient's private neoantigens increased during treatment. However, immune responses directed to vaccine antigens that may arise from VACCIMEL's somatic mutations and human polymorphisms remain unexplored.
View Article and Find Full Text PDFiScience
January 2025
Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands.
Proton pump inhibitors have been explored for potentiating cancer therapies via reverting the tumor acidity and promoting the activation of anti-tumor immune responses. To regulate the intracellular pH of melanoma and immunosuppressive myeloid cells, we developed poly(L-lactide-co-glycolide) nanoparticles loaded with esomeprazole (ESO-NPs). The effect of ESO-NPs on melanoma cells was observed as alkalinization and reduction of melanin content accompanied by a decrease of microphthalmia-associated transcription factor (MITF), poliovirus receptor (PVR), and programmed death ligand 1 (PD-L1) immune checkpoint expression.
View Article and Find Full Text PDFPhotochem Photobiol
January 2025
Department of Biochemistry, Institute of Chemistry, University of Sao Paulo, São Paulo, Brazil.
Melanoma is an aggressive cancer that has attracted attention in recent years due to its high mortality rate of 80%. Damage caused by oxidative stress generated by radical (type I reaction) and singlet oxygen, O (type II reaction) oxidative reactions may induce cancer. Thus, studies that aim to unveil the mechanism that drives these oxidative damage processes become relevant.
View Article and Find Full Text PDFCurr Med Chem
January 2025
Biotechnology Institute, Ankara University, Keçiören, TR-06135, Ankara, Turkey.
Introduction: Melanoma is one of the most dangerous and common types of cancer in humans. In order to minimize the toxicity and side effects of melanoma treatment, it is important to identify drug candidates that have strong anti-cancer activity and fewer side effects. Lobaric acid is a small molecule that has been found to have significant anti-cancer effects on various types of cancer cells.
View Article and Find Full Text PDFBMC Biol
January 2025
Cancer Research Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada.
Background: Uveal melanoma (UM) is the most common intraocular tumor in adults, arises either de novo from normal choroidal melanocytes (NCMs) or from pre-existing nevi that stem from NCMs and are thought to harbor UM-initiating mutations, most commonly in GNAQ or GNA11. However, there are no commercially available NCM cell lines, nor is there a detailed protocol for developing an oncogene-mutated CM line (MutCM) to study UM development. This study aimed to establish and characterize premalignant CM models from human donor eyes to recapitulate the cell populations at the origin of UM.
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