Repository of Research and Investigative Information

Repository of Research and Investigative Information

Kurdistan University of Medical Sciences

Melatonin as an adjuvant in radiotherapy for radioprotection and radiosensitization

(2019) Melatonin as an adjuvant in radiotherapy for radioprotection and radiosensitization. Clinical and Translational Oncology.

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Official URL: https://www.scopus.com/inward/record.uri?eid=2-s2....

Abstract

It is estimated that more than half of cancer patients undergo radiotherapy during the course of their treatment. Despite its beneficial therapeutic effects on tumor cells, exposure to high doses of ionizing radiation (IR) is associated with several side effects. Although improvements in radiotherapy techniques and instruments could reduce these side effects, there are still important concerns for cancer patients. For several years, scientists have been trying to modulate tumor and normal tissue responses to IR, leading to an increase in therapeutic ratio. So far, several types of radioprotectors and radiosensitizers have been investigated in experimental studies. However, high toxicity of chemical sensitizers or possible tumor protection by radioprotectors creates a doubt for their clinical applications. On the other hand, the protective effects of these radioprotectors or sensitizer effects of radiosensitizers may limit some type of cancers. Hence, the development of some radioprotectors without any protective effect on tumor cells or low toxic radiosensitizers can help improve therapeutic ratio with less side effects. Melatonin as a natural body hormone is a potent antioxidant and anti-inflammatory agent that shows some anti-cancer properties. It is able to neutralize different types of free radicals produced by IR or pro-oxidant enzymes which are activated following exposure to IR and plays a key role in the protection of normal tissues. In addition, melatonin has shown the ability to inhibit long-term changes in inflammatory responses at different levels, thereby ameliorating late side effects of radiotherapy. Fortunately, in contrast to classic antioxidants, some in vitro studies have revealed that melatonin has a potent anti-tumor activity when used alongside irradiation. However, the mechanisms of its radiosensitive effect remain to be elucidated. Studies suggested that the activation of pro-apoptosis gene, such as p53, changes in the metabolism of tumor cells, suppression of DNA repair responses as well as changes in biosynthesis of estrogen in breast cancer cells are involved in this process. In this review, we describe the molecular mechanisms for radioprotection and radiosensitizer effects of melatonin. Furthermore, some other proposed mechanisms that may be involved are presented. © 2018, Federación de Sociedades Españolas de Oncología (FESEO).

Item Type: Article
Keywords: catalase; endothelin 1; epidermal growth factor receptor; free radical; glutathione; glutathione peroxidase; growth factor; hypoxia inducible factor 1alpha; interleukin 1; interleukin 13; interleukin 4; interleukin 6; interleukin 8; melatonin; protein p53; reactive nitrogen species; reactive oxygen metabolite; somatomedin C; superoxide dismutase; tumor necrosis factor; vasculotropin; antioxidant; melatonin; radioprotective agent; radiosensitizing agent, adjuvant radiotherapy; angiogenesis; antiinflammatory activity; antineoplastic activity; antioxidant activity; apoptosis; autophagy; B lymphocyte; cancer patient; cell death; cell proliferation; DNA damage; DNA repair; estrogen synthesis; gene expression; immune response; inflammation; ionizing radiation; macrophage; MCF-7 cell line; metabolism; natural killer cell; necroptosis; necrosis; oxidative stress; protein expression; radiation protection; radiosensitization; regulatory T lymphocyte; Review; senescence; signal transduction; T lymphocyte; tumor growth; upregulation; animal; drug effect; human; neoplasm; procedures; radiation injury; radiation tolerance, Animals; Antioxidants; Humans; Melatonin; Neoplasms; Radiation Injuries; Radiation Tolerance; Radiation-Protective Agents; Radiation-Sensitizing Agents; Radiotherapy
Page Range: pp. 268-279
Journal or Publication Title: Clinical and Translational Oncology
Volume: 21
Number: 3
Publisher: Springer-Verlag Italia s.r.l.
Identification Number: 10.1007/s12094-018-1934-0
ISSN: 1699048X
Depositing User: مهندس جمال محمودپور
URI: http://eprints.muk.ac.ir/id/eprint/1769

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