The effect of the presence of melanin on the response of mammalian cells to ionizing radiation was investigated in a model system utilizing the ability of Chinese hamster ovary cells to incorporate melanin by endocytosis. Cells were incubated in monolayer cultures from 2 to 20 hours with melanin prepared from 'beef eye' or synthesized by air oxidation of 3,4-dihydroxyphenylalanine. For asynchronous cultures, the survival curve parameters for cells incubated with both types of melanin were indistinguishable from those of the same cells without added melanin. The radiation response to fractionated doses of 6 Gy separated by various periods did not indicate any effect of melanin on the extent or kinetics of repair of sublethal damage. Likewise, the repair of potentially lethal damage in plateau phase cultures was unaffected by the presence of melanin. Thus the explanation for the clinical radiation resistance of melanomas in the absence of a direct radiation effect might more likely be found in consideration of other factors such as the role of melanin in oxygen consumption or in differentiation.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1080/09553008514550761 | DOI Listing |
Arch Dermatol Res
January 2025
Department of Genetics & Biotechnology, Graduate School of Biotechnology, College of Life Sciences, Kyung Hee University, Youngin, 17104, Republic of Korea.
Abnormal melanin synthesis within melanocytes can result in pigmentary skin disorders. Although pigmentation alterations associated with inflammation are frequently observed, the precise reason for this clinical observation is still unknown. More specifically, although many cytokines are known to be critical for inflammatory skin processes, it is unclear how they affect epidermal melanocyte function.
View Article and Find Full Text PDFArch Dermatol Res
January 2025
Burn and Wound Repair Center, The Third Hospital of Hebei Medical University, No. 139, Ziqiang Road, Shijiazhuang, Hebei Province, 050035, China.
This study aimed to investigate the role of transforming growth factor-beta 3 (TGF-β3) secreted by adipose-derived stem cells (ADSCs) in suppressing melanin synthesis during the wound healing process, particularly in burn injuries, and to explore the underlying mechanisms involving the cAMP/PKA signaling pathway. ADSCs were isolated from C57BL/6 mice and characterized using flow cytometry and differentiation assays. A burn injury model was established in mice, followed by UVB irradiation to induce hyperpigmentation.
View Article and Find Full Text PDFArch Dermatol Res
January 2025
Dermatology and Venereology Department, Faculty of Medicine for Girls, Al-Azhar University, Cairo, Egypt.
Both the surgical non-cultured melanocyte-keratinocyte transplant procedure (MKTP) and intradermal injection of 5-Fluorouracil (5-FU) are effective in the treatment of vitiligo. Intrablisters injection of MKTP was done in one study with better results than MKTP application after ablative CO2 laser of the reciepient area. However, intrablister injection of 5-FU was not done before.
View Article and Find Full Text PDFPigment Cell Melanoma Res
January 2025
Department of Cell Biology and Anatomy, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada.
Circadian regulation of skin pigmentation is essential for thermoregulation, ultraviolet (UV) protection, and synchronization of skin cell renewal. This regulation involves both cell-autonomous photic responses and non-cell-autonomous hormonal control, particularly through melatonin produced in a light-sensitive manner. Photosensitive opsins, cryptochromes, and melatonin regulate circadian rhythms in skin pigment cells.
View Article and Find Full Text PDFInt Immunopharmacol
January 2025
Pharmacology Division, Council of Scientific and Industrial Research-Indian Institute of Integrative Medicine, Jammu, Jammu and Kashmir 180001, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India. Electronic address:
Melanoma is an aggressive form of malignancy that originates from melanin-producing cells known as melanocytes underlying the basal layer of the epidermis with a poor prognosis, low survival rates, and limited treatment options. Although several specific and effective systematic strategies for treating melanoma have been established, the underlying molecular mechanism of melanoma progression, mortality and the promising therapeutic options remain elusive. Shikonin (SK), a natural naphthoquinone derived from a medicinal herbaceous plant, has been shown to inhibit the proliferation of several cancer cells.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!