Ultraviolet irradiation of normal human keratinocytes induces a cytotoxic effect. The chromophore for this effect is believed to be genomic DNA. However, DNA damage is known to be repaired in UVB irradiated keratinocytes. The trigger for this DNA repair is potentially damaged DNA itself. To test the hypothesis that damaged DNA can induce the host cell's own DNA repair mechanism, we treated the keratinocytes with the damaged DNA and evaluated its cytoprotective effects. We have observed that fragmented calf thymus DNA irradiated and damaged with a UVC light can induce a protective effect in cultured human keratinocytes. Keratinocytes treated with UVC damaged DNA fragments are less susceptible to UVB irradiation-induced cell death as measured by neutral red uptake. Unirradiated exogenous DNA did not induce this protective effect. Similar protective effects can be seen with irradiated salmon sperm DNA. UVC damaged DNA fragments induced 60% increase in protection in human HaCaT keratinocyte in culture to the cell death induced by UVB. Similar protection was observed with UVC irradiated oligothymidylic acid (dT3-dT5) which increased the survival of human HaCaT keratinocytes after UVB irradiated by 50%. Isolated mononucleotides, irradiated or not, do not increase UVB survivability. Cellular DNA synthesis was greatly inhibited by UVB, becoming undetectable at 40 mJ/cm(2). Exogenous treatment with damaged fragments causes immediate and significant inhibition of total cellular DNA synthesis. This inhibition was dose dependent. Cells that undergo damage to their DNA are known to inhibit endogenous DNA synthesis via p53 suppressor gene activation. This is believed to allow them sufficient time to repair the host DNA. The cellular response to exogenous damaged DNA may be a similar mechanism.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1159/000049386 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Multiplexed single-cell imaging reveals diverging subpopulations with distinct senescence phenotypes during long-term senescence induction.
Geroscience
January 2025
Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
Cellular senescence is a phenotypic state that contributes to the progression of age-related disease through secretion of pro-inflammatory factors known as the senescence-associated secretory phenotype (SASP). Understanding the process by which healthy cells become senescent and develop SASP factors is critical for improving the identification of senescent cells and, ultimately, understanding tissue dysfunction. Here, we reveal how the duration of cellular stress modulates the SASP in distinct subpopulations of senescent cells.
View Article and Find Full Text PDFDe novo transcriptome assembly and analysis during agarwood induction in Gyrinops versteegii Gilg. seedling.
Sci Rep
January 2025
Plant Science and Biotechnology Research Group, School of Life Sciences and Technology, Institut Teknologi Bandung, West Java, 40132, Indonesia.
Agarwood is a highly prized resinous wood produced by select members of the Thymelaeaceae plant family. Its formation in Aquilaria species has been expedited using various induction techniques, revealing insights into factors affecting the chemical constituents of artificially induced agarwood. Building on this, our research delved into the potential of another Thymelaeaceae member, Gyrinops versteegii, as an alternate agarwood source.
View Article and Find Full Text PDFCalcium hydroxide nanoparticles induce cell death, genomic instability, oxidative stress and apoptotic gene dysregulation on human HepG2 cells.
Sci Rep
January 2025
Faculty of Biotechnology, October University for Modern Sciences and Arts, 6th of October, Egypt.
Calcium hydroxide nanoparticles (Ca(OH)NPs) possess potent antimicrobial activities and unique physical and chemical properties, making them valuable across various fields. However, limited information exists regarding their effects on genomic DNA integrity and their potential to induce apoptosis in normal and cancerous human cell lines. This study thus aimed to evaluate the impact of Ca(OH)NPs on cell viability, genomic DNA integrity, and oxidative stress induction in human normal skin fibroblasts (HSF) and cancerous hepatic (HepG2) cells.
View Article and Find Full Text PDFUncovering the chromatin-mediated transcriptional regulatory network governing cold stress responses in fish immune cells.
J Genet Genomics
January 2025
Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China; International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai 201306, China; Marine Biomedical Science and Technology Innovation Platform of Lin-gang Special Area, Shanghai 201306, China. Electronic address:
Temperature fluctuations challenge ectothermic species, particularly tropical fish dependent on external temperatures for physiological regulation. However, the molecular mechanisms through which low-temperature stress impacts immune responses in these species, especially in relation to chromatin accessibility and epigenetic regulation, remain poorly understood. In this study, we investigate chromatin and transcriptional changes in the head kidney and thymus tissues of Nile tilapia (Oreochromis niloticus), a tropical fish of significant economic importance, under cold stress.
View Article and Find Full Text PDFThe extracts from Centaurea species abolished the cytotoxic effects of doxorubicin on breast cancer cell line - MCF-7 and bortezomib on prostate cancer cell line- PC3.
Food Chem Toxicol
January 2025
Independent Medical Biology Unit, Faculty of Pharmacy, Medical University of Lublin, 8b Jaczewski Street 20-093 Lublin, Poland. Electronic address:
The use of plant extracts by cancer patients during chemotherapy poses potential risks, as they may reduce the effectiveness of treatment or interact negatively with chemotherapeutic drugs. There is a lack of comprehensive studies evaluating the effects of various Centaurea spp. plant extracts on chemotherapy outcomes, highlighting the need for caution and medical supervision.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!