DNA Damage In Cells Research Articles

A novel protein encoded by circCOPA inhibits the malignant phenotype of glioblastoma cells and increases their sensitivity to temozolomide by disrupting the NONO–SFPQ complex

Glioblastoma (GBM) represents a primary malignant brain tumor. Temozolomide resistance is a major hurdle in GBM treatment. Proteins encoded by circular RNAs (circRNAs) can modulate the sensitivity of multiple tumor chemotherapies. However, the impact of circRNA-encoded proteins on GBM sensitivity to temozolomide remains unknown. Herein, we discover a circRNA (circCOPA) through the circRNA microarray profile in GBM samples, which can encode a novel 99 amino acid protein (COPA-99aa) through its internal ribosome entry site. Functionally, circCOPA overexpression in GBM cells inhibits cell proliferation, migration, and invasion in vitro and growth in vivo. Rather than itself, circCOPA mainly functions as a suppressive effector by encoding COPA-99aa. Moreover, we reveal that circCOPA is downregulated in GBM tissues and high expression of circCOPA is related to a better prognosis in GBM patients. Mechanistically, a heteromer of SFPQ and NONO is required for double-strand DNA break repair. COPA-99aa disrupts the dimerization of NONO and SFPQ by separately binding with the NONO and SFPQ proteins, thus resulting in the inhibition of proliferation or invasion and the increase of temozolomide-induced DNA damage in GBM cells. Collectively, our data suggest that circCOPA mainly contributes to inhibiting the GBM malignant phenotype through its encoded COPA-99aa and that COPA-99aa increases temozolomide-induced DNA damage by interfering with the dimerization of NONO and SFPQ. Restoring circCOPA or COPA-99aa may increase the sensitivity of patients to temozolomide.

Determination of the Effect of Thymoquinone on DNA Damage in Kidney Cells Treated to High Glucose Depending on Time and Dosage by Comet Assay

The purpose of this study was to assess the anti-genotoxic potential of thymoquinone (TQ) against DNA damage in NRK-52E cells treated with high glucose using the comet assay technique single cell gel electrophoresis method. Cells were propagated by regular passages in in vitro conditions. TQ proliferative concentration (10μM) and IC25 (3rd-hour: 550 mM, 12th-hour: 240 mM, 24th-hour: 200 mM) and IC50 (3rd-hour: 760 mM, 12th-hour: 400 mM, 24th-hour: 280 mM) values for each hour of high glucose and were determined separately with MTT method. At these concentrations, the cells were divided into control(C), Thymoquinone (TQ), high glucose(G) and high glucose plus thymoquinone (GT) groups; It was incubated with the indicated substances for 3, 12, 24 hours. DNA damage was evaluated by applying the comet assay protocol and the results were calculated as DNA damage index (DDI). While DDI levels were observed to be significantly higher (p<0.05) in all groups administered high glucose compared to the control, a significant decrease was determined in all groups in which TQ was added along with high glucose. It was determined that high concentrations of glucose had genotoxic effects on kidney cells, and TQ administration together with high glucose, depending on concentration and time, had a significant effect on reducing DNA damage. However, it was concluded that the application of only thymoquinone significantly increased the DDI value compared to the control, and this was a data worth investigating in future studies. Additionally, TQ inhibited DNA damage. These results demonstrated the importance of TQ against nephrotic syndrome with its high antioxidant properties.

Polθ Inhibitor (ART558) Demonstrates a Synthetic Lethal Effect with PARP and RAD52 Inhibitors in Glioblastoma Cells.

DNA repair proteins became the popular targets in research on cancer treatment. In our studies we hypothesized that inhibition of DNA polymerase theta (Polθ) and its combination with Poly (ADP-ribose) polymerase 1 (PARP1) or RAD52 inhibition and the alkylating drug temozolomide (TMZ) has an anticancer effect on glioblastoma cells (GBM21), whereas it has a low impact on normal human astrocytes (NHA). The effect of the compounds was assessed by analysis of cell viability, apoptosis, proliferation, DNA damage and cell cycle distribution, as well as gene expression. The main results show that Polθ inhibition causes a significant decrease in glioblastoma cell viability. It induces apoptosis, which is accompanied by a reduction in cell proliferation and DNA damage. Moreover, the effect was stronger when dual inhibition of Polθ with PARP1 or RAD52 was applied, and it is further enhanced by addition of TMZ. The impact on normal cells is much lower, especially when considering cell viability and DNA damage. In conclusion, we would like to highlight that Polθ inhibition used in combination with PARP1 or RAD52 inhibition has great potential to kill glioblastoma cells, and shows a synthetic lethal effect, while sparing normal astrocytes.

PEITC Induces DNA Damage and Inhibits DNA Repair-Associated Proteins in Human Retinoblastoma Cells In Vitro.

Phenethyl isothiocyanate (PEITC), a natural product, exists in biological activities, including anticancer activity in many human cancer cells. No information shows that PEITC affects DNA damage in human retinoblastoma (RB) cells in vitro. In this study, the aim of experiments was to determine whether PEITC decreased total viable cell number or not by inducing protein expressions involved in DNA damage and repair in Y79 RB cells in vitro. Total cell viability was measured by PI exclusion assay, and PEITC reduced the total Y79 viable cell numbers in a dose-dependent manner. DNA condensation and DNA impairment were conducted by DAPI staining and comet assays, respectively, in Y79 cells. The findings show that PEITC induced DNA condensation dose-dependently based on the brighter fluorescence of cell nuclei stained by DAPI staining. PEITC-induced DNA damage showed a more extended DNA migration smears than that of the control, which was performed by a comet assay. Western blotting was performed to measure the protein expressions involved in DNA damage and repair, which showed that PEITC at 2.5-10 μM increased NRF2, HO-1, SOD (Mn), and catalase; however, it decreased SOD (Cu/Zn) except 10 μM PEITC treatment, and decreased glutathione, which were associated with oxidativestress. Furthermore, PEITC increased DNA-PK, MDC1, H2A.XpSer139, ATMpSer1981, p53, p53pSer15, PARP, HSP70, and HSP90, but decreased TOPIIα, TOPIIβ, and MDM2pSer166 that were associated with DNA damage and repair mechanism in Y79 cells. The examination from confocal laser microscopy shows that PEITC increased H2A.XpSer139 and p53pSer15, and decreased glutathione and TOPIIα in Y79 cells. In conclusion, the cytotoxic effects of PEITC on reducing the number of viable cells may be due to the induction of DNA damage and the alteration of DNA repair proteins in Y79 cells in vitro.

Safe, simple and multifunctional hydroxyapatite nanoparticles for efficient overcoming of tumor multidrug resistance

Multidrug resistance (MDR) of cancer is the most common obstacle to chemotherapy. Many complex multifunctional nanoparticles have been developed for combination of two or more therapeutics to overcome MDR. Unlike these sophisticated nanoparticles, hydroxyapatite nanoparticles (HAPNs) were found to be able to inhibit cell proliferation of various human cancer cells. Herein, with different MDR cells and chemotherapeutic drugs, we tested whether HAPNs can be widely applied in fighting cancer drug resistance. Rod-shaped HAPNs were synthesized by the aqueous precipitation and then successfully loaded with paclitaxel (PTX) and doxorubicin (DOX) by physical adsorption to obtain pH-responsive drug-loaded nanoparticles, PHAPNs and DHAPNs, respectively. Plain HAPNs exhibited selective cytotoxicity to drug-resistant breast cancer cells MCF-7/ADR, lung cancer cells H69AR and A549/PTX, while spared normal human liver cells L-02. HAPN treatment led to an increase in the apoptosis ratio, a decrease in cell viability and a sustained increase in intracellular calcium ion level in MDR cells. Furthermore, HAPNs facilitated the delivery and accumulation of both drugs, thereby improving the DOX-induced DNA damage in H69AR cells, as well as the acetylation of α-tubulin and cell cycle arrest led by PTX in MCF-7/ADR and A549/PTX cells. Drug-loaded HAPNs greatly enhanced mitochondrial damage, inhibited ATP synthesis and efflux pump activity, and triggered both the intrinsic and extrinsic apoptosis induced by HAPNs or drugs alone. HAPNs acted synergistically with DOX and PTX, resulting in a >6-fold reduction in the IC50 compared with free drugs for these MDR cells. Notably, PHAPNs successfully suppressed the tumor growth in A549/PTX xenograft mice and exhibited excellent biocompatibility in vivo. These findings demonstrated that HAPNs may be widely utilized to reverse the resistance of various drug-resistant cells, providing a simple but practical approach to overcome MDR of cancer.

Restoration of Radiosensitivity by Soya Isoflavone Genistein is Accomplished by Facilitating DNA Damage Response in Radioresistant Cervical Cancer in vitro

ABSTRACT Context: Enhancing radiotherapeutic efficacy in tumor cells and sparing the normal tissues are major clinical concerns for the betterment of cancer therapy. Genistein (GEN) being a radiosensitizer ameliorates the effectiveness of radiation-induced cell killing by inducing DNA damage. This molecule is accountable for minimizing radiation-related toxicity and protecting healthy cells. However, the explicit mechanism of action of such molecules needs exploration. Aims: The objective of this study is to investigate the mechanistic action of GEN in cervical cancer cell radiosensitization. Settings and Design: Cervical squamous carcinoma cell SiHa and a radioresistant subline SiHa/RR (developed and isolated from SiHa) were taken for this study. The experiments were performed by pretreating the cells with IC30 dose of GEN, followed by acute irradiation to detect the impact of GEN in imparting radiosensitivity. Subjects and Methods: Optimal dose selection of GEN was performed by MTT assay, and radiosensitizing potency was determined by pretreating the cells with IC30 dose of GEN, followed by challenging with acute incremental doses of radiation. Mechanistic parameters were checked by clonogenic assay, cell cycle analysis, DNA damage estimation, apoptosis, and wound healing-sphere-forming assay. Statistical Analysis Used: Statistical analysis was performed in GraphPad software by performing the Student’s t-test. Results: Results depicted decreased numbers of colonies, increased frequency of DNA damage and apoptotic cells, and suppressed wound healing ability along with restrained sphere-forming ability upon the intervention of cells with GEN before radiation exposure. Such observations implied that GEN pretreatment renders improved radiosensitivity in cervical cancer by increased DNA damage-mediated G2/M arrest with subsequent apoptosis. Conclusions: GEN by inducing DNA damage stimulates radiation-induced cell killing in vitro.

Removal of the catalytic subunit of DNA-protein kinase in the proximal tubules promotes DNA and tubular damage during kidney injury.

Tubular epithelial cell damage can be repaired through a series of complex signaling pathways. An early event in many forms of tubular damage is the observation of DNA damage, which can be repaired by specific pathways depending upon the type of genomic alteration.. In this study, we report that the catalytic subunit of DNA protein kinase (DNA-PKcs), a central DNA repair enzyme involved in sensing DNA damage and performing double stranded DNA break repair, plays an important role in the extent of tubular epithelial cell damage following exposure to injurious acute and chronic stimuli. Selective loss of DNA-PKcs in the proximal tubules led to increased markers of kidney dysfunction, DNA damage, and tubular epithelial cell injury in multiple models of acute kidney injury, specifically bilateral renal ischemia-reperfusion injury and single dose of cisplatin (15 mg/kg IP). In contrast, in a mouse model of kidney fibrosis and chronic kidney disease (UUO),the protective effects of DNA-PKcs was not as obvious histologically from the tissue sections. In the absence of proximal tubular DNA-PKcs, there was reduced levels of fibrotic markers, α-SMA and fibronectin, which suggests that there may be a biphasic role of DNA-PKcs depending upon the conditions exerted upon the kidney. In conclusion, this study demonstrates that the catalytic subunit of DNA-PKcs plays a context-dependent role in the kidney to reduce DNA damage during exposure to various types of acute, but not chronic forms of injurious stimuli.

In Vitro Safety Study on the Use of Cold Atmospheric Plasma in the Upper Respiratory Tract.

Cold atmospheric plasma (CAP) devices generate reactive oxygen and nitrogen species, have antimicrobial and antiviral properties, but also affect the molecular and cellular mechanisms of eukaryotic cells. The aim of this study is to investigate CAP treatment in the upper respiratory tract (URT) to reduce the incidence of ventilator-associated bacterial pneumonia (especially superinfections with multi-resistant pathogens) or viral infections (e.g., COVID-19). For this purpose, the surface-microdischarge-based plasma intensive care (PIC) device was developed by terraplasma medical GmbH. This study analyzes the safety aspects using in vitro assays and molecular characterization of human oral keratinocytes (hOK), human bronchial-tracheal epithelial cells (hBTE), and human lung fibroblasts (hLF). A 5 min CAP treatment with the PIC device at the "throat" and "subglottis" positions in the URT model did not show any significant differences from the untreated control (ctrl.) and the corresponding pressurized air (PA) treatment in terms of cell morphology, viability, apoptosis, DNA damage, and migration. However, pro-inflammatory cytokines (MCP-1, IL-6, and TNFα) were induced in hBTE and hOK cells and profibrotic molecules (collagen-I, FKBP10, and αSMA) in hLF at the mRNA level. The use of CAP in the oropharynx may make an important contribution to the recovery of intensive care patients. The results indicate that a 5 min CAP treatment in the URT with the PIC device does not cause any cell damage. The extent to which immune cell activation is induced and whether it has long-term effects on the organism need to be carefully examined in follow-up studies in vivo.

Cyclic RGD conjugated PEG-PLGA nanoparticle enhances preventative effect of bilirubin on the development of ultraviolet-B (UVB)-induced cataract

Age related cataract (ARC) is characterized by protein conformational disorder with aging stands out as an independent risk factor. Therefore, mitigation of oxidative stress and DNA damage within the lens emerges as a potential therapeutic strategy. While topical administration remains the most common treatment modality for ocular disorder, drug bioavailability is hindered by the cornea epithelium barrier. In this study, we developed a novel cyclic Arg-Gly-Asp (cRGD)-conjugated nanoparticle encapsulating bilirubin (cRNM@BR), an endogenous antioxidant, to combat against cellular senescence and lens opacity associated with ARC. Immunofluorescence staining assay confirmed that cRGD modification significantly prolonged nanoparticle retention on the ocular surface by targeting integrin expressed on corneal epithelium. Moreover, through LC-MS/MS analysis, we demonstrated the enhanced transcorneal penetration efficacy of cRGD-modified nanodrugs both in vivo and in vitro. Our mechanistic investigations revealed that cRNM entered human corneal epithelial cells (HCECs) by clathrin and micropinocytosis-mediated pathways, with the ER/Golgi pathway facilitating its exocytosis. In a mouse model of ultraviolet B (UVB)-induced cataract, topical application of cRNM@BR effectively alleviated intracellular reactive oxygen species (ROS) levels and DNA damage in lens epithelial cells (LECs), thereby preventing cellular senescence and lens opacity. Transcriptomics analysis of LECs in UVB-exposed group and cRNM@BR pretreated group indicated significant enrichment of the cGAS/STING pathway. Further experiments determined that cRNM@BR prevented cellular senescence and lens opacity by ameliorating the cGAS/STING pathway. In conclusion, our findings underscore the therapeutic potential of cRNM@BR in ARC management and highlight the efficacy of cRGD-conjugated nanoplatform for intraocular delivery.

Promising Effects of Novel Supplement Formulas in Preventing Skin Aging in 3D Human Keratinocytes.

Dietary intervention is considered a safe preventive strategy to slow down aging. This study aimed to evaluate the protective effects of a commercially available supplement and six simpler formulations against DNA damage in 3D human keratinocytes. The ingredients used are well known and were combined into various formulations to test their potential anti-aging properties. Firstly, we determined the formulations' safe concentration by evaluating cytotoxicity and cell viability through spectrophotometric assays. We then examined the presence of tumor p53 binding protein 1 and phosphorylated histone H2AX foci, which are markers of genotoxicity. The foci count revealed that a 24-h treatment with the supplement did not induce DNA damage, and significantly reduced DNA damage in cells exposed to neocarzinostatin for 2 h. Three of the simpler formulations showed similar results. Moreover, the antioxidant activity was tested using a recently developed whole cell-based chemiluminescent bioassay; results showed that a 24-h treatment with the supplement and three simpler formulations significantly reduced intracellular H2O2 after pro-oxidant injury, thus suggesting their possible antiaging effect. This study's originality lies in the use of a 3D human keratinocyte cell model and a combination of natural ingredients targeting DNA damage and oxidative stress, providing a robust evaluation of their anti-aging potential.

Increased DNA damage of adipose tissue-derived mesenchymal stem cells under inflammatory conditions

Cells have evolved various DNA repair mechanisms to prevent DNA damage from building up. Malfunctions during DNA repair can influence cellular homeostasis because they can bring on genomic instability through the improper recognition of DNA damage or dysregulation of the repair process. Maintaining proper DNA repair is also essential for stem cells (SCs), as they provide a differentiated cell population to the living organism. SCs are regularly used in personalized stem cell therapy. Patients must be treated with specific activators to produce these SCs effectively. This report investigated the impact of treating mesenchymal stem cells (MSC) with lipopolysaccharide, tumor necrosis factor, interferon-gamma, polyinosinic acid, interleukin 1 beta, while monitoring their transcription-related response using next-generation sequencing. RNA sequencing revealed robust gene expression changes, including those of specific genes encoding proteins implicated in DNA damage response. Stem cells can effectively repair specific DNA damages; moreover, they fail to undergo senescence or cell death when genetic lesions accumulate. Here, we draw attention to an elevated DNA repair activation following MSC induction, which may be the main reason for the ineffective stem cell transplantation and may also contribute to the genetic drift that can initiate tumor formation.

Structures of LIG1 uncover the mechanism of sugar discrimination against 5′-RNA-DNA junctions during ribonucleotide excision repair

Ribonucleotides in DNA cause several types of genome instability and can be removed by ribonucleotide excision repair (RER) that is finalized by DNA ligase 1 (LIG1). However, the mechanism by which LIG1 discriminates the RER intermediate containing a 5'-RNA–DNA lesion generated by RNase H2-mediated cleavage of ribonucleotides remains unknown. Here, we determine X-ray structures of LIG1/5'-rG:C at the initial step of ligation where AMP is bound to the active site of the ligase, and uncover a large conformational change downstream the nick resulting in a shift at Arg(R)871 residue in the Adenylation domain of the ligase. Furthermore, we demonstrate a diminished ligation of the nick DNA substrate with a 5'-ribonucleotide in comparison to an efficient end joining of the nick substrate with a 3'-ribonucleotide by LIG1. Finally, our results demonstrate that mutations at the active site residues of the ligase and LIG1 disease-associated variants significantly impact the ligation efficiency of RNA–DNA heteroduplexes harboring “wrong” sugar at 3'- or 5'-end of nick. Collectively, our findings provide a novel atomic insight into proficient sugar discrimination by LIG1 during processing of the most abundant form of DNA damage in cells, genomic ribonucleotides, during initial step of the RER pathway.

Bombyx mori nucleopolyhedrovirus LEF-2 disrupts the cell cycle in the G2/M phase by triggering a host cell DNA damage response.

It is a common strategy for viruses to block the host cell cycle to favour their DNA replication. Baculovirus, being a double-stranded DNA virus, can arrest the cell cycle in the G2/M phase to facilitate its replication. However, the key viral genes and mechanisms crucial for inducing cell cycle arrest remain poorly understood. Here, we initially examined the impacts of several Bombyx mori nucleopolyhedrovirus (BmNPV) DNA replication-associated genes: ie1, lef-1, lef-2, lef-3, lef-4, odv-ec27 and dbp. We assessed their effects on both the host cells' DNA replication and cell cycle. Our findings reveal that when the lef-2 gene was overexpressed, it led to a significant increase in the number of cells in the G2/M phase and a reduction in the number of cells in the S phase. Furthermore, we discovered that the LEF-2 protein is located in the virogenic stroma and confirmed its involvement in viral DNA replication. Additionally, by employing interference and overexpression experiments, we found that LEF-2 influences host cell DNA replication and blocks the cell cycle in the G2/M phase by regulating the expression of CyclinB and CDK1. Finally, we found that BmNPV lef-2 triggered a DNA damage response in the host cell, and inhibiting this response removed the cell cycle block caused by BmNPV LEF-2. Thus, our findings indicate that the BmNPV lef-2 gene plays a crucial role in viral DNA replication and can regulate host cell cycle processes. This study furthers our understanding of baculovirus-host cell interactions and provides new insight into the molecular mechanisms of antiviral research.

Impact of environmental concentrations of fipronil on DNA integrity and brain structure of Bombus atratus bumblebees

Fipronil (FP) is an insecticide used in the treatment and control of pests, but it also adversely affects bees. Currently, there is no data on the genotoxic effects of FP in the brain of bumblebees. Thus, through the comet assay and routine morphological analysis, we analyzed the morphological effects and potential genotoxicity of environmentally relevant concentrations of FP on the brain of Bombus atratus. Bumblebees were exposed at concentrations of 2.5 μg/g and 3.5 μg/g for 96 hours. After the exposure, the brains were removed for morphological and morphometric analysis, and the comet assay procedure - used to detect DNA damage in individual cells using electrophoresis. Our data showed that both concentrations (2.5 μg/g and 3.5 μg/g) caused DNA damage in brain cells. These results corroborate the morphological data. We observed signs of synapse loss in the calyx structure, intercellular spaces between compact inner and non-compact inner cells, and cell swelling. This study provides unprecedented evidence of the effects of FP on DNA and cellular structures in the brain of B. atratus and reinforces the need to elucidate its toxic effects on other species to allow future risk assessments and conservation projects.

Albumin-Based Microneedles for Spatiotemporal Delivery of Temozolomide and Niclosamide to Resistant Glioblastoma.

Glioblastoma (GBM) is the most common and aggressive malignant brain tumor. Standard therapy includes maximal surgical resection, radiotherapy, and adjuvant temozolomide (TMZ) administration. However, the rapid development of TMZ resistance and the impermeability of the blood-brain barrier (BBB) significantly hinder the therapeutic efficacy. Herein, we developed spatiotemporally controlled microneedle patches (BMNs) loaded with TMZ and niclosamide (NIC) to overcome GBM resistance. We found that hyaluronic acid (HA) increased the viscosity of bovine serum albumin (BSA) and evidenced that concentrations of BSA/HA exert an impact degradation rates exposure to high-temperature treatment, showing that the higher BSA/HA concentrations result in slower drug release. To optimize drug release rates and ensure synergistic antitumor effects, a 15% BSA/HA solution constituting the bottoms of BMNs was chosen to load TMZ, showing sustained drug release for over 28 days, guaranteeing long-term DNA damage in TMZ-resistant cells (U251-TR). Needle tips made from 10% BSA/HA solution loaded with NIC released the drug within 14 days, enhancing TMZ's efficacy by inhibiting the activity of O6-methylguanine-DNA methyltransferase (MGMT). BMNs exhibit superior mechanical properties, bypass the BBB, and gradually release the drug into the tumor periphery, thus significantly inhibiting tumor proliferation and expanding median survival in mice. The on-demand delivery of BMNs patches shows a strong translational potential for clinical applications, particularly in synergistic GBM treatment.

The protective effects of PCSK9 inhibitors on DNA damage in peripheral blood mononuclear cells in familial hypercholesterolemic patients

The protective effects of PCSK9 inhibitors on DNA damage in peripheral blood mononuclear cells in familial hypercholesterolemic patients

Neuropeptide alpha-Melanocyte stimulating hormone preserves corneal endothelial morphology in a murine model of Fuchs dystrophy

Fuchs endothelial corneal dystrophy is a heterogenous disease with multifactorial etiology, and genetic, epigenetic, and exogenous factors contributing to its pathogenesis. DNA damage plays a significant role, with ultraviolet-A (UV-A) emerging as a key contributing factor. We investigate the potential application of neuropeptide α-melanocyte stimulating hormone (α-MSH) in mitigating oxidative stress induced endothelial damage. First, we examined the effects of α-MSH on a cultured human corneal endothelial cell line (HCEnC-21T) exposed to hydrogen peroxide (H2O2) induced oxidative DNA damage. We performed immunofluorescence and flow cytometry to assess DNA damage and cell death in the cultured cells. Additionally, we used an established mouse model that utilizes ultraviolet light to induce corneal endothelial cell damage resulting in decreased CEnC number, increased cell size variability, and decreased percentage of hexagonal cells. This endothelial decompensation leads to an increase in corneal thickness. Following UV-A exposure, the mice were systemically treated with α-MSH, either immediately after exposure (early treatment) or beginning two weeks post-exposure (delayed treatment). To evaluate treatment efficacy, we analyzed CEnC density and morphology using in vivo confocal microscopy, and central corneal thickness using anterior segment optical coherence tomography. Our findings demonstrated that α-MSH treatment effectively protects HCEnC-21T from free-radical induced oxidative DNA damage and subsequent cell death. In vivo, α-MSH treatment, mitigated the loss of CEnC density, deterioration of cell morphology and suppression of the resultant corneal swelling. These results underline the potential application of α-MSH as a therapeutic agent for mitigating corneal endothelial damage.

Imidacloprid affects human cells through mitochondrial dysfunction and oxidative stress

Given their relatively low persistence and mammalian toxicity, neonicotinoid pesticides have been extensively used worldwide and are omnipresent in the environment. Recent studies have shown that neonicotinoids may pose adverse effects on non-target organisms other than the known neurotoxicity, raising emerging concerns that these insecticides might pose human health risk through additional toxicity pathways. In the present study, the mitochondria function, oxidative stress, DNA damages, and genes transcription levels were examined in the human neuroblastoma SH-SY5Y cells after 48-h exposure to imidacloprid at concentrations from 0.05 to 200 μmol/L. Results showed that imidacloprid induced mitochondrial dysfunction with the degradation of adenosine triphosphate (ATP) and mitochondrial membrane potential (MMP) levels. In addition, imidacloprid caused oxidative stress by stimulating the generation of reactive oxygen species (ROS) and hydrogen peroxide (H2O2) via the disruption of calcium ion level and mitochondrial function. Ultimately, the oxidative stress continued to produce DNA damage and apoptosis in SH-SY5Y cells at imidacloprid concentrations above 47.6 μmol/L. Among the evaluated endpoints, ATP was the most sensitive, with a median activity concentration of 0.74 μmol/L. The 5 % hazard concentration of imidacloprid was estimated to be 0.69 μmol/L, which can be used as a threshold for human health risk assessment for imidacloprid. Collectively, our results provide an important support for further research on potential toxicity of neonicotinoids related to mitochondrial toxicity in humans.

Ciclopirox platinum(IV) conjugates suppress tumors by promoting mitophagy and provoking immune responses

Mitophagy is an important target for antitumor drugs development. A series of ciclopirox (CPX) platinum(IV) hybrids targeting PTEN induced putative kinase 1 (PINK1)/Parkin mediated mitophagy were designed and prepared as antitumor agents. The dual CPX platinum(IV) complex with cisplatin core was screened out as a candidate, which displayed promising antitumor activities both in vitro and in vivo. Mechanistically, it caused serious DNA damage in tumor cells. Then, remarkable mitochondrial damage was induced accompanied by the mitochondrial membrane depolarization and reactive oxygen species generation, which further promoted apoptosis through the Bcl-2/Bax/Caspase3 pathway. Furthermore, mitophagy was ignited via the PINK1/Parkin/P62/LC3 axis, and exhibited positive influence on promoting the apoptosis of tumor cells. The antitumor immunity was boosted by the block of immune check point programmed cell death ligand-1 (PD-L1), which further increased the density of T cells in tumors. Subsequently, the metastasis of tumor cells was inhibited by inhibiting angiogenesis in tumors.

Stereotactic centralized ablative radiation therapy: A novel methodology in treating bulky tumor and its technical realization.

159 Background: Bulky tumors pose significant challenges to traditional treatment modalities such as surgery, chemotherapy, and conventional radiotherapy. This study introduces a novel therapeutic approach named as Stereotactic-Core-Ablative-Radiation-Therapy (SCART), designed to deliver an ablative dose to a substantial core of the bulky tumor while quickly decreasing to a lower dose at the tumor periphery. Methods: A SCART-Treatment-Volume (STV) at the core of the GTV was predefined to administer an ablative radiation dose, aiming to induce DNA damage in cancer cells and potentially trigger biological cancer-killing effects. Utilizing Linac-based VMAT or Cyberknife techniques with 6MV photon beams, multiple radiation fields intersect and optimize at STV, generating an ablative dose at the STV. The dose rapidly diminishes to a safe level at the edge of GTV sparing the surrounding tissue. In the phase-1 trial, nineteen patients with 21 bulky tumors enrolled, receiving SCART at five dose levels (15GyX1, 15GyX2, 15GyX3, 18GyX3, 21GyX3, and 24GyX3), while maintaining the GTV's peripheral dose at 5Gy each fraction. Results: All patients completed treatment with average beam-on time of 8.9min and average treatment time of 18.5min. Mean follow-up time is 15.4 month. No grade-III or higher toxicity was observed. 7/19 patients still survive, with the overall survival of 40% at 30 months. Mean tumor volume shrinks by 60% between initial 301cc and post-SCART volumes of 118cc. Long-term follow-up revealed that 14/21 tumors achieved Partial Response, 2/21 Complete-Response, 3/21 Stable-Disease, and 1/21 Progressive-Disease, leading to an encouraging local control of 95%. Conclusions: SCART emerges as a safe and effective strategy for treating bulky malignant tumors, demonstrating excellent local control and overall survival. Multiple treatment courses were feasible. The results from phase-1 study suggest that SCART could revolutionize the treatment landscape for bulky tumors, offering a promising avenue for further exploration and application in clinical practice.