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Ultraviolet light-related DNA damage mutation signature distinguishes cutaneous from mucosal or other origin for head and neck squamous cell carcinoma of unknown primary site
摘要： Background: Head and neck squamous cell carcinoma of unknown primary site (HNSCCUP) is a diagnostic challenge. Identification of an ultraviolet (UV) light-related DNA damage signature using next-generation sequencing (NGS) can classify the primary site of origin as cutaneous. Methods: A 62-year-old male was seen with 2 months of left neck swelling. He was a lifetime nonsmoker but had a history of cutaneous squamous cell carcinoma (SCC) of the left helix. He was also found to have left hilar adenopathy. He had a p16-negative HNSCCUP on fine needle aspiration (FNA) biopsy of the left neck. Results: NGS of the FNA specimen revealed a high number of somatic mutations that were mostly C to T transitions, indicating a UV mutation signature and confirming the diagnosis of cutaneous SCC. Conclusions: Identification of a UV DNA damage signature with NGS distinguishes HNSCCUP of cutaneous vs mucosal or other squamous cell carcinoma origin.
关键词： unknown primary squamous cell carcinoma of head and neck,cutaneous tumor mutation burden,next-generation sequencing,ultraviolet light-related DNA damage signature,skin cancer
更新于2025-09-23 15:23:52
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Spectral features of nuclear DNA in human sperm assessed by Raman Microspectroscopy: Effects of UV-irradiation and hydration
摘要： Raman Microspectroscopy represents an innovative tool for the assessment of sperm biochemical features otherwise undetectable by routine semen analysis. Previously, it was shown that induced DNA damage can be detected in smeared sperm by this technique. This novel readout may be of value for clinical settings especially if it can be transferred to living cells. Yet, starting with living sperms this study was carried-out using a variety of conditions to disclose the Raman features of sperm nuclei under different hydration conditions and UV exposure. Human sperm were immobilized and Raman spectra were obtained from individual sperm as repeated measurements. To create conditions with controlled DNA damage, sperm samples were exposed to ultraviolet light. Several media were used to evaluate their effect on Raman spectra in aqueous conditions. To substantiate differences between the experimental conditions, the spectra were analyzed by Principal Component Analysis. We observed that spectra of sperm nuclei obtained in different solutions showed a qualitatively unchanged spectral pattern showing the principal signals related to DNA. Evaluating the effect of ultraviolet light generated the finding that spectra representing DNA damage were only observed in dry conditions but not in aqueous medium. Thus, Raman microspectroscopy was successfully applied for sperm analysis in different conditions, among them in live spermatozoa in aqueous solution during the initial measurement, revealing the principle use of this technique. However, implementation of Raman spectroscopy as a technique for clinical sperm analysis and selection may be especially relevant when DNA evaluation can be established using live sperm.
关键词： hydration,DNA damage,sperm,UV-irradiation,Raman Microspectroscopy
更新于2025-09-23 15:21:21
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Blue LED phototherapy in preterm infants: effects on an oxidative marker of DNA damage
摘要： background Phototherapy is used on the majority of preterm infants with unconjugated hyperbilirubinaemia. The use of fluorescent tube phototherapy is known to induce oxidative DNA damage in infants and has largely been replaced by blue light- emitting diode phototherapy (BLP). To date, it is unknown whether BLP also induces oxidative DNA damage in preterm infants. Objective To determine whether BLP in preterm infants induces oxidative DNA damage as indicated by 8- hydroxy-2′deoxyguanosine (8- OHdG). Design Observational cohort study. Methods Urine samples (n=481) were collected in a cohort of 40 preterm infants (24–32 weeks’ gestational age) during the first week after birth. Urine was analysed for the oxidative marker of DNA damage 8- OHdG and for creatinine, and the 8- OHdG/creatinine ratio was calculated. Durations of phototherapy and levels of irradiance were monitored as well as total serum bilirubin concentrations. results BLP did not alter urinary 8- OHdG/creatinine ratios (B=0.2, 95% CI ?6.2 to 6.6) at either low (10–30 μW/cm2/nm) or high (>30 μW/cm2/nm) irradiance: (B=2.3, 95% CI ?5.7 to 10.2 and B=?3.0, 95% CI ?11.7 to 5.6, respectively). Also, the 8- OHdG/creatinine ratios were independent on phototherapy duration (B=?0.1, 95% CI ?0.3 to 0.1). Conclusions BLP at irradiances up to 35 μW/cm2/nm given to preterm infants ≤32 weeks’ gestation does not affect 8- OHdG, an oxidative marker of DNA damage.
关键词： preterm infants,phototherapy,8-hydroxy-2′deoxyguanosine,blue light-emitting diode phototherapy,oxidative DNA damage
更新于2025-09-23 15:21:01
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Quercetin encapsulated biodegradable plasmonic nanoparticles for photothermal therapy of hepatocellular carcinoma cells
摘要： Photothermal therapy (PTT) is emerging as an effective treatment modality for cancer due to its non-invasive nature. However, the pro-inflammatory necrotic cell death during PTT limits its successful clinical application. Here, we have developed quercetin (QE) loaded biodegradable plasmonic nanoparticles that can specifically induce apoptosis in cancer cells after PTT. We have synthesized gold-coated liposome (LiposAu) and QE loaded gold-coated liposome (QE-LiposAu) nanoparticles by in situ reduction of chloroauric acid with ascorbic acid in the presence of bare liposomes (Lipos) or QE loaded liposomes (QE-Lipos), respectively. The gold coating was confirmed by transmission electron microscopic analysis, dynamic light scattering, and zeta potential measurements. LiposAu and QE-LiposAu nanoparticles showed a similar level of temperature rise upon 750 nm near-infrared (NIR) laser (650 mW, 3 W cm-2) irradiation. The photothermal conversion efficiency of QE-LiposAu nanoparticles was determined to be ~75%. The efficacy of PTT was found to be dependent on the internalization efficiency of LiposAu nanoparticles in cancer cells. Importantly, QE-LiposAu nanoparticles showed increased PTT efficacy over LiposAu nanoparticles in hepatocellular carcinoma cells (Huh-7). Moreover, QE-LiposAu nanoparticles induced apoptosis-mediated cell death after the PTT, and the extent of apoptosis was significantly higher than the LiposAu nanoparticles in Huh-7 cells. Further, QE-LiposAu nanoparticles-mediated PTT depolymerized microtubules network, suppressed Hsp70 expression, and caused DNA damage. QE-LiposAu nanoparticles were also found to be hemocompatible. The results together suggested that biodegradable QE-LiposAu nanoparticles are promising photothermal agents for cancer therapy.
关键词： heat shock protein,liposome,microtubule,apoptosis,gold nanoparticles,DNA damage,Photothermal therapy
更新于2025-09-12 10:27:22
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Transcription-coupled nucleotide excision repair is coordinated by ubiquitin and SUMO in response to ultraviolet irradiation
摘要： Cockayne Syndrome (CS) is a severe neurodegenerative and premature aging autosomal-recessive disease, caused by inherited defects in the CSA and CSB genes, leading to defects in transcription-coupled nucleotide excision repair (TC-NER) and consequently hypersensitivity to ultraviolet (UV) irradiation. TC-NER is initiated by lesion-stalled RNA polymerase II, which stabilizes the interaction with the SNF2/SWI2 ATPase CSB to facilitate recruitment of the CSA E3 Cullin ubiquitin ligase complex. However, the precise biochemical connections between CSA and CSB are unknown. The small ubiquitin-like modifier SUMO is important in the DNA damage response. We found that CSB, among an extensive set of other target proteins, is the most dynamically SUMOylated substrate in response to UV irradiation. Inhibiting SUMOylation reduced the accumulation of CSB at local sites of UV irradiation and reduced recovery of RNA synthesis. Interestingly, CSA is required for the efficient clearance of SUMOylated CSB. However, subsequent proteomic analysis of CSA-dependent ubiquitinated substrates revealed that CSA does not ubiquitinate CSB in a UV-dependent manner. Surprisingly, we found that CSA is required for the ubiquitination of the largest subunit of RNA polymerase II, RPB1. Combined, our results indicate that the CSA, CSB, RNA polymerase II triad is coordinated by ubiquitin and SUMO in response to UV irradiation. Furthermore, our work provides a resource of SUMO targets regulated in response to UV or ionizing radiation.
关键词： SUMOylation,DNA damage response,transcription-coupled nucleotide excision repair,Cockayne Syndrome,UV irradiation,ubiquitination
更新于2025-09-12 10:27:22
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Photocarcinogenesis & Photoprotection || Molecular and Genetic Response of Human Skin Under Ultraviolet Radiation
摘要： Ultraviolet (UV) radiation is recognized as an essential risk factor due to its dual role of affecting the human skin. Primarily, it is required for natural vitamin D synthesis in the skin which is indispensable for human health in many constructive ways. On the other hand, UV radiation acts as a non-specific damaging agent and a mutagen as well. UV radiation has potential to cause both cancer initiation and progression. Excessive and repeated exposure to UV is associated with health risks, including pigment changes, wrinkle formation, atrophy, and malignancy. Epidemiologically and molecularly UV is linked to DNA damage, either directly or indirectly via oxidative injury resulting in various types of skin cancer. Genetic factors also stimulate threat of UV-mediated skin anomalies. This chapter emphasizes on genetic and molecular mechanisms of pigmentation, tanning, DNA damage and repair, Melanocortin 1 receptor (MC1R) gene expression, photoproduct formation, and p53 mutation.
关键词： UV radiation,MC1R,Pigmentation,Photoproduct,DNA damage
更新于2025-09-10 09:29:36
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Arabidopsis E2Fc is required for the DNA damage response under UV-B radiation epistatically over the microRNA396 and independently of E2Fe
摘要： UV-B radiation inhibits plant growth, and this inhibition is, to a certain extent, regulated by miR396-mediated repression of Growth Regulating transcription Factors (GRFs). Moreover, E2Fe transcription factor also modulates Arabidopsis leaf growth. Here, we provide evidence that, at UV-B intensities that induce DNA damage, E2Fc participates in the inhibition of cell proliferation. We demonstrate that E2Fc deficient plants show a lower inhibition of leaf size under UV-B conditions that damage DNA, decreased cell death after exposure and altered SOG1 and ATR expression. Interestingly, the previously reported participation of E2Fe in UV-B responses, which is a transcriptional target of E2Fc, is independent and different of that described for E2Fc. On the other hand, we here demonstrate that E2Fc has an epistatic role over the miR396 pathway under UV-B conditions. Finally, we show that inhibition of cell proliferation by UV-B is independent of the regulation of class II TCP transcription factors. Together, our results demonstrate that E2Fc is required for miR396 activity on cell proliferation under UV-B, and that its role is independent of E2Fe, probably modulating DNA damage responses through the regulation of SOG1 and ATR transcript levels.
关键词： E2F transcription factor,DNA damage response,UV-B,cell proliferation,miR396
更新于2025-09-10 09:29:36
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Biological activity of PtIV prodrugs triggered by riboflavin-mediated bioorthogonal photocatalysis
摘要： We have recently demonstrated that riboflavin (Rf) functions as unconventional bioorthogonal photocatalyst for the activation of PtIV prodrugs. In this study, we show how the combination of light and Rf with two PtIV prodrugs is a feasible strategy for light-mediated pancreatic cancer cell death induction. In Capan-1 cells, which have high tolerance against photodynamic therapy, Rf-mediated activation of the cisplatin and carboplatin prodrugs cis,cis,trans-[Pt(NH3)2(Cl)2(O2CCH2CH2CO2H)2] (1) and cis,cis,trans-[Pt(NH3)2(CBDCA)(O2CCH2CH2CO2H)2] (2, where CBDCA = cyclobutane dicarboxylate) resulted in pronounced reduction of the cell viability, including under hypoxia conditions. Such photoactivation mode occurs to a considerable extent intracellularly, as demonstrated for 1 by uptake and cell viability experiments. 195Pt NMR, DNA binding studies using circular dichroism, mass spectrometry and immunofluorescence microscopy were performed using the Rf-1 catalyst-substrate pair and indicated that cell death is associated with the efficient light-induced formation of cisplatin. Accordingly, Western blot analysis revealed signs of DNA damage and activation of cell death pathways through Rf-mediated photochemical activation. Phosphorylation of H2AX as indicator for DNA damage, was detected for Rf-1 in a strictly light-dependent fashion while in case of free cisplatin also in the dark. Photochemical induction of nuclear pH2AX foci by Rf-1 was confirmed in fluorescence microscopy again proving efficient light-induced cisplatin release from the prodrug system.
关键词： riboflavin,pancreatic cancer,DNA damage,PtIV prodrugs,photocatalysis
更新于2025-09-10 09:29:36
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Photo-Induced Depletion of Binding Sites in DNA-PAINT Microscopy
摘要： The limited photon budget of fluorescent dyes is the main limitation for localization precision in localization-based super-resolution microscopy. Points accumulation for imaging in nanoscale topography (PAINT)-based techniques use the reversible binding of fluorophores and can sample a single binding site multiple times, thus elegantly circumventing the photon budget limitation. With DNA-based PAINT (DNA-PAINT), resolutions down to a few nanometers have been reached on DNA-origami nanostructures. However, for long acquisition times, we find a photo-induced depletion of binding sites in DNA-PAINT microscopy that ultimately limits the quality of the rendered images. Here we systematically investigate the loss of binding sites in DNA-PAINT imaging and support the observations with measurements of DNA hybridization kinetics via surface-integrated fluorescence correlation spectroscopy (SI-FCS). We do not only show that the depletion of binding sites is clearly photo-induced, but also provide evidence that it is mainly caused by dye-induced generation of reactive oxygen species (ROS). We evaluate two possible strategies to reduce the depletion of binding sites: By addition of oxygen scavenging reagents, and by the positioning of the fluorescent dye at a larger distance from the binding site.
关键词： photo-induced DNA damage,surface-integrated fluorescence correlation spectroscopy (SI-FCS),reactive oxygen species,super-resolution microscopy,DNA-PAINT
更新于2025-09-09 09:28:46
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Integrating an ex-vivo skin biointerface with electrochemical DNA biosensor for direct measurement of the protective effect of UV blocking agents
摘要： Skin cancer is the most frequent kind of cancer in white people in many parts of the world. UV-induced DNA damage and genetic mutation can subsequently lead to skin cancer. Therefore development of new biosensing strategies for detection of UV-induced DNA damage is of great importance. Here we demonstrate a novel combination of an ex-vivo skin biointerface and an electrochemical DNA sensor for the direct detection of UV induced DNA damage and investigation the protective effect of various UV blockers (Zinc-oxide (ZnO), titanium-dioxide (TiO2) nanoparticles (NPs) and sunscreens) against DNA damage. A diazonium modified screen-printed carbon electrode immobilized with a DNA sequence related to the p53 tumour suppressor gene, the most commonly affected gene in human UV-induced skin cancer, was applied as an electrochemical DNA sensor. Electrochemical impedance spectroscopy (EIS) was employed for the detection of DNA damage induced by UV-A radiation by following the changes in charge transfer resistance (Rct). The protective effects of UV blockers applied onto a pig skin surface (a suitable model representing human skin) were successfully detected by the DNA sensor. We observed that the naked skin has little UV protection showing an 18.2% decreases in ?R/R values compared to the control, while applying both NPs and NP-formulated sunscreens could significantly reduce DNA damage, resulting in a decrease in ?R/R values of 67.1% (ZnO NPs), 77.2% (TiO2 NPs), 77.1% (sunscreen 1) and 92.4% (sunscreen 2), respectively. Moreover, doping moisturising cream with NPs could provide a similar DNA protective effect. This new method is a biologically relevant alternative to animal testing and offers advantages such as fast, easy and inexpensive processing, in addition to its miniaturised dimension, and could be used for a range of applications in other sources of DNA damage and the protective effect of different UV blocking agents and other topical formulations.
关键词： sunscreens,electrochemical DNA biosensor,skin biointerface,DNA damage,nanoparticles
更新于2025-09-04 15:30:14