Baicalin protects against hepatocyte injury caused by aflatoxin B1 via the TP53-related ferroptosis Pathway.

OBJECTIVE: Baicalin has antioxidative, antiviral, and anti-inflammatory properties. However, its ability to alleviate oxidative stress (OS) and DNA damage in liver cells exposed to aflatoxin B1 (AFB1), a highly hepatotoxic compound, remains uncertain. In this study, the protective effects of baicalin on AFB1-induced hepatocyte injury and the mechanisms underlying those effects were investigated. METHODS: Stable cell lines expressing CYP3A4 were established using lentiviral vectors to assess oxidative stress levels by conducting assays to determine the content of reactive oxygen species (ROS), malondialdehyde (MDA), and superoxide dismutase (SOD). Additionally, DNA damage was evaluated by 8-hydroxy-2-deoxyguanosine (8-OHdG) and comet assays. Transcriptome sequencing, molecular docking, and in vitro experiments were conducted to determine the mechanisms underlying the effects of baicalin on AFB1-induced hepatocyte injury. In vivo, a rat model of hepatocyte injury induced by AFB1 was used to evaluate the effects of baicalin. RESULTS: In vitro, baicalin significantly attenuated AFB1-induced injury caused due to OS, as determined by a decrease in ROS, MDA, and SOD levels. Baicalin also considerably decreased AFB1-induced DNA damage in hepatocytes. This protective effect of baicalin was found to be closely associated with the TP53-mediated ferroptosis pathway. To elaborate, baicalin physically interacts with P53, leading to the suppression of the expression of GPX4 and SLC7A11, which in turn inhibits ferroptosis. In vivo findings showed that baicalin decreased DNA damage and ferroptosis in AFB1-treated rat liver tissues, as determined by a decrease in the expression of γ-H2AX and an increase in GPX4 and SLC7A11 levels. Overexpression of TP53 weakened the protective effects of baicalin. CONCLUSIONS: Baicalin can alleviate AFB1-induced OS and DNA damage in liver cells via the TP53-mediated ferroptosis pathway. In this study, a theoretical foundation was established for the use of baicalin in protecting the liver from the toxic effects of AFB1.

Alantolactone Induced Apoptosis and DNA Damage of Cervical Cancer through ATM/CHK2 Signaling Pathway.

Traditional Chinese Medicine, known for its minimal side effects and significant clinical efficacy, has attracted considerable interest for its potential in cancer therapy. In particular, Inula helenium L. has demonstrated effectiveness in inhibiting a variety of cancers. This study focuses on alantolactone (ALT), a prominent compound from Inula helenium L., recognized for its anti-cancer capabilities across multiple cancer types. The primary objective of this study is to examine the influence of ALT on the proliferation, apoptosis, cell cycle, and tumor growth of cervical cancer (CC) cells, along with its associated signaling pathways. To determine protein expression alterations, Western blot analysis was conducted. Furthermore, an in vivo model was created by subcutaneously injecting HeLa cells into nude mice to assess the impact of ALT on cervical cancer. Our research thoroughly investigates the anti-tumor potential of ALT in the context of CC. ALT was found to inhibit cell proliferation and induce apoptosis in SiHa and HeLa cell lines, particularly targeting ataxia-telangiectasia mutated (ATM) proteins associated with DNA damage. The suppression of DNA damage and apoptosis induction when ATM was inhibited underscores the crucial role of the ATM/cell cycle checkpoint kinase 2 (CHK2) axis in ALT's anti-tumor effects. In vivo studies with a xenograft mouse model further validated ALT's effectiveness in reducing CC tumor growth and promoting apoptosis. This study offers new insights into how ALT combats CC, highlighting its promise as an effective anti-cervical cancer agent and providing hope for improved treatment outcomes for CC patients.

IL-17A Drives Oxidative Stress and Cell Growth in A549 Lung Epithelial Cells: Potential Protective Action of Oleuropein.

IL-17A drives inflammation and oxidative stress, affecting the progression of chronic lung diseases (asthma, chronic obstructive pulmonary disease (COPD), lung cancer, and cystic fibrosis). Oleuropein (OLP) is a polyphenolic compound present in olive oil and widely included in the Mediterranean diet. It exerts antioxidant and anti-inflammatory activities, oxidative stress resistance, and anticarcinogenic effects with a conceivable positive impact on human health. We hypothesized that OLP positively affects the mechanisms of oxidative stress, apoptosis, DNA damage, cell viability during proliferation, and cell growth in alveolar epithelial cells and tested its effect in a human alveolar epithelial cell line (A549) in the presence of IL-17A. Our results show that OLP decreases the levels of oxidative stress (Reactive Oxygen Species, Mitochondrial membrane potential) and DNA damage (H2AX phosphorylation-ser139, Olive Tail Moment data) and increases cell apoptosis in A549 cells exposed to IL-17A. Furthermore, OLP decreases the number of viable cells during proliferation, the migratory potential (Scratch test), and the single cell capacity to grow within colonies as a cancer phenotype in A549 cells exposed to IL-17A. In conclusion, we suggest that OLP might be useful to protect lung epithelial cells from oxidative stress, DNA damage, cell growth, and cell apoptosis. This effect might be exerted in lung diseases by the downregulation of IL-17A activities. Our results suggest a positive effect of the components of olive oil on human lung health.

Polyploid giant cancer cells induced by Docetaxel exhibit a senescence phenotype with the expression of stem cell markers in ovarian cancer cells.

Docetaxel (Doc) plays a crucial role in clinical antineoplastic practice. However, it is continuously documented that tumors frequently develop chemoresistance and relapse, which may be related to polyploid giant cancer cells (PGCCs). The aim of this study was investigate the formation mechanism and biological behavior of PGCCs induced by Doc. Ovarian cancer cells were treated with Doc, and then the effect of Doc on cellular viability was evaluated by MTT assay and microscopic imaging analysis. The biological properties of PGCCs were further evaluated by Hoechst 33342 staining, cell cycle and DNA content assay, DNA damage response (DDR) signaling detection, ß-galactosidase staining, mitochondrial membrane potential detection, and reverse transcription-quantitative polymerase chain reaction. The results indicated that Doc reduced cellular viability; however, many cells were still alive, and were giant and polyploid. Doc increased the proportion of cells stayed in the G2/M phase and reduced the number of cells. In addition, the expression of γ-H2A.X was constantly increased after Doc treatment. PGCCs showed senescence-associated ß-galactosidase activity and an increase in the monomeric form of JC-1. The mRNA level of octamer-binding transcription factor 4 (OCT4) and krüppel-like factor 4 (KLF4) was significantly increased in PGCCs. Taken together, our results suggest that Doc induces G2/M cell cycle arrest, inhibits the proliferation and activates persistent DDR signaling to promote the formation of PGCCs. Importantly, PGCCs exhibit a senescence phenotype and express stem cell markers.

Dual inhibition of SUMOylation and MEK conquers MYC-expressing KRAS-mutant cancers by accumulating DNA damage.

BACKGROUND: KRAS mutations frequently occur in cancers, particularly pancreatic ductal adenocarcinoma, colorectal cancer, and non-small cell lung cancer. Although KRASG12C inhibitors have recently been approved, effective precision therapies have not yet been established for all KRAS-mutant cancers. Many treatments for KRAS-mutant cancers, including epigenome-targeted drugs, are currently under investigation. Small ubiquitin-like modifier (SUMO) proteins are a family of small proteins covalently attached to and detached from other proteins in cells via the processes called SUMOylation and de-SUMOylation. We assessed whether SUMOylation inhibition was effective in KRAS-mutant cancer cells. METHODS: The efficacy of the first-in-class SUMO-activating enzyme E inhibitor TAK-981 (subasumstat) was assessed in multiple human and mouse KRAS-mutated cancer cell lines. A gene expression assay using a TaqMan array was used to identify biomarkers of TAK-981 efficacy. The biological roles of SUMOylation inhibition and subsequent regulatory mechanisms were investigated using immunoblot analysis, immunofluorescence assays, and mouse models. RESULTS: We discovered that TAK-981 downregulated the expression of the currently undruggable MYC and effectively suppressed the growth of MYC-expressing KRAS-mutant cancers across different tissue types. Moreover, TAK-981-resistant cells were sensitized to SUMOylation inhibition via MYC-overexpression. TAK-981 induced proteasomal degradation of MYC by altering the balance between SUMOylation and ubiquitination and promoting the binding of MYC and Fbxw7, a key factor in the ubiquitin-proteasome system. The efficacy of TAK-981 monotherapy in immunocompetent and immunodeficient mouse models using a mouse-derived CMT167 cell line was significant but modest. Since MAPK inhibition of the KRAS downstream pathway is crucial in KRAS-mutant cancer, we expected that co-inhibition of SUMOylation and MEK might be a good option. Surprisingly, combination treatment with TAK-981 and trametinib dramatically induced apoptosis in multiple cell lines and gene-engineered mouse-derived organoids. Moreover, combination therapy resulted in long-term tumor regression in mouse models using cell lines of different tissue types. Finally, we revealed that combination therapy complementally inhibited Rad51 and BRCA1 and accumulated DNA damage. CONCLUSIONS: We found that MYC downregulation occurred via SUMOylation inhibition in KRAS-mutant cancer cells. Our findings indicate that dual inhibition of SUMOylation and MEK may be a promising treatment for MYC-expressing KRAS-mutant cancers by enhancing DNA damage accumulation.

Dulaglutide reduces oxidative DNA damage and hypermethylation in the somatic cells of mice fed a high-energy diet by restoring redox balance, inflammatory responses, and DNA repair gene expressions.

Obesity is an established risk factor for numerous malignancies, although it remains uncertain whether the disease itself or weight-loss drugs are responsible for a greater predisposition to cancer. The objective of the current study was to determine the impact of dulaglutide on genetic and epigenetic DNA damage caused by obesity, which is a crucial factor in the development of cancer. Mice were administered a low-fat or high-fat diet for 12 weeks, followed by a 5-week treatment with dulaglutide. Following that, modifications of the DNA bases were examined using the comet assay. To clarify the underlying molecular mechanisms, oxidized and methylated DNA bases, changes in the redox status, levels of inflammatory cytokines, and the expression levels of some DNA repair genes were evaluated. Animals fed a high-fat diet exhibited increased body weights, elevated DNA damage, oxidation of DNA bases, and DNA hypermethylation. In addition, obese mice showed altered inflammatory responses, redox imbalances, and repair gene expressions. The findings demonstrated that dulaglutide does not exhibit genotoxicity in the investigated conditions. Following dulaglutide administration, animals fed a high-fat diet demonstrated low DNA damage, less oxidation and methylation of DNA bases, restored redox balance, and improved inflammatory responses. In addition, dulaglutide treatment restored the upregulated DNMT1, Ogg1, and p53 gene expression. Overall, dulaglutide effectively maintains DNA integrity in obese animals. It reduces oxidative DNA damage and hypermethylation by restoring redox balance, modulating inflammatory responses, and recovering altered gene expressions. These findings demonstrate dulaglutide's expediency in treating obesity and its associated complications.

Selective anti-tumor activity of glutathione-responsive abasic site trapping agent in anaplastic thyroid carcinoma.

Anaplastic thyroid carcinoma (ATC) is a rare but highly aggressive thyroid cancer with poor prognosis. Killing cancer cells by inducing DNA damage or blockage of DNA repair is a promising strategy for chemotherapy. It is reported that aldehyde-reactive alkoxyamines can capture the AP sites, one of the most common DNA lesions, and inhibit apurinic/apyrimidinic endonuclease 1(APE1)-mediated base excision repair (BER), leading to cell death. Whether this strategy can be employed for ATC treatment is rarely investigated. The aim of this study is to exploit GSH-responsive AP site capture reagent (AP probe-net), which responses to the elevated glutathione (GSH) levels in the tumor micro-environment (TME), releasing reactive alkoxyamine to trap AP sites and block the APE1-mediated BER for targeted anti-tumor activity against ATC. In vitro experiments, including MTT andγ-H2AX assays, demonstrate their selective cytotoxicity towards ATC cells over normal thyroid cells. Flow cytometry analysis suggests that AP probe-net arrests the cell cycle in the G2/M phase and induces apoptosis. Western blotting (WB) results show that the expression of apoptotic protein increased with the increased concentration of AP probe-net. Further in vivo experiments reveal that the AP probe-net has a good therapeutic effect on subcutaneous tumors of the ATC cells. In conclusion, taking advantage of the elevated GSH in TME, our study affords a new strategy for targeted chemotherapy of ATC with high selectivity and reduced adverse effects.

Genotoxicity and cytotoxicity evaluation of a heat-not-burn product.

'Heat-not-burn' products (HnBP) contain lower levels of harmful substances than traditional cigarettes, but the use of these products warrants further toxicological evaluation. We have compared the cytotoxicity and genotoxicity of a heat-not burn product with conventional cigarettes, in vivo and in vitro. Male Sprague Dawley rats were exposed to mainstream smoke from conventional cigarettes or a HnBP, for 4 or 28 days, followed by isolation of bone marrow polychromatic erythrocytes (PCE) and histological examination of the testes. Chinese hamster lung fibroblast cells were exposed in vitro to total particulate matter from cigarette smoke obtained through Cambridge filters. The cytotoxicity and genotoxicity of total particulate matter were assessed by the neutral red uptake assay, chromosome aberration assay, in vitro micronucleus test, comet assay, and Ames assay. In the short-term exposure rat models, only the conventional-cigarettes group showed a significant increase in the ratio of micronuclei to total PCE. There was no significant difference in rat testis histology in the long-term exposure models. In vitro, in the neutral red uptake assay, the HnBP product showed lower cytotoxicity than conventional cigarettes. Conventional cigarettes showed greater genotoxicity in the chromosome aberration assay, high-dose Ames tests with exogenous metabolic activation, and micronucleus tests. In summary, our results suggest that HnBP have lower cytotoxicity and genotoxicity than conventional cigarettes.

Repeat treatment of organotypic airway cultures with ethyl methanesulfonate causes accumulation of somatic cell mutations without expansion of bronchial-carcinoma-specific cancer driver mutations.

The human in vitro organotypic air-liquid-interface (ALI) airway tissue model is structurally and functionally similar to the human large airway epithelium and, as a result, is being used increasingly for studying the toxicity of inhaled substances. Our previous research demonstrated that DNA damage and mutagenesis can be detected in human airway tissue models under conditions used to assess general and respiratory toxicity endpoints. Expanding upon our previous proof-of-principle study, human airway epithelial tissue models were treated with 6.25-100 µg/mL ethyl methanesulfonate (EMS) for 28 days, followed by a 28-day recovery period. Mutagenesis was evaluated by Duplex Sequencing (DS), and clonal expansion of bronchial-cancer-specific cancer-driver mutations (CDMs) was investigated by CarcSeq to determine if both mutation-based endpoints can be assessed in the same system. Additionally, DNA damage and tissue-specific responses were analyzed during the treatment and following the recovery period. EMS exposure led to time-dependent increases in mutagenesis over the 28-day treatment period, without expansion of clones containing CDMs; the mutation frequencies remained elevated following the recovery. EMS also produced an increase in DNA damage measured by the CometChip and MultiFlow assays and the elevated levels of DNA damage were reduced (but not eliminated) following the recovery period. Cytotoxicity and most tissue-function changes induced by EMS treatment recovered to control levels, the exception being reduced proliferating cell frequency. Our results indicate that general, respiratory-tissue-specific and genotoxicity endpoints increased with repeat EMS dosing; expansion of CDM clones, however, was not detected using this repeat treatment protocol. DISCLAIMER: This article reflects the views of its authors and does not necessarily reflect those of the U.S. Food and Drug Administration. Any mention of commercial products is for clarification only and is not intended as approval, endorsement, or recommendation.

H2O2 promotes photodynamic efficacy of TMPyP4 against ovarian cancer in vitro by downregulating HIF-1α expression.

Photodynamic therapy (PDT), employing photosensitizers to induce formation of reactive oxygen species (ROS) for tumor elimination, is emerging as a promising treatment modality in oncology due to its unique benefits. However, the PDT application in ovarian cancer, the most prevalent and lethal type of gynecological malignancy with a severe hypoxic microenvironment, remains unknown. This study revealed that photosensitizer TMPyP4 exhibited enhanced efficacy under H2O2 stimulation, with minimal change in cytotoxicity compared to TMPyP4 alone. The results showed that H2O2 increased ROS production induced by TMPyP4, leading to exacerbated mitochondrial dysfunction and DNA damage, ultimately inhibiting proliferation and inducing apoptosis in ovarian cancer cells. Mechanistically, H2O2 primarily enhanced the therapeutic efficacy of PDT with TMPyP4 against ovarian cancer cells by degrading HIF-1α, which subsequently modulated the HIF-1 signaling pathway, thereby alleviating the hypoxic environment in ovarian cancer cells. Our findings underscore the therapeutic potential of targeting HIF-1α within the hypoxic microenvironment for PDT in ovarian cancer and propose a novel integrated strategy for PDT treatment of this malignancy in vitro.

Investigation into the Neuroprotective and Therapeutic Potential of Plant-Derived Chk2 Inhibitors.

Nature provides us with a rich source of compounds with a wide range of applications, including the creation of innovative drugs. Despite advancements in chemically synthesized therapeutics, natural compounds are increasingly significant, especially in cancer treatment, a leading cause of death globally. One promising approach involves the use of natural inhibitors of checkpoint kinase 2 (Chk2), a critical regulator of DNA repair, cell cycle arrest, and apoptosis. Chk2's activation in response to DNA damage can lead to apoptosis or DNA repair, influencing glycolysis and mitochondrial function. In cancer therapy, inhibiting Chk2 can disrupt DNA repair and cell cycle progression, promoting cancer cell death and enhancing the efficacy of radiotherapy and chemotherapy. Additionally, Chk2 inhibitors can safeguard non-cancerous cells during these treatments by inhibiting p53-dependent apoptosis. Beyond oncology, Chk2 inhibition shows potential in treating hepatitis C virus (HCV) infections, as the virus relies on Chk2 for RNA replication in neurodegenerative diseases like amyotrophic lateral sclerosis (ALS), in which DNA damage plays a crucial role. Plant-derived Chk2 inhibitors, such as artemetin, rhamnetin, and curcumin, offer a promising future for treating various diseases with potentially milder side effects and broader metabolic impacts compared to conventional therapies. The review aims to underscore the immense potential of natural Chk2 inhibitors in various therapeutic contexts, particularly in oncology and the treatment of other diseases involving DNA damage and repair mechanisms. These natural Chk2 inhibitors hold significant promise for revolutionizing the landscape of cancer treatment and other diseases. Further research into these compounds could lead to the development of innovative therapies that offer hope for the future with fewer side effects and enhanced efficacy.

Trans-[Pt(amine)Cl2(PPh3)] Complexes Target Mitochondria and Endoplasmic Reticulum in Gastric Cancer Cells.

Gastric cancer prognosis is still notably poor despite efforts made to improve diagnosis and treatment of the disease. Chemotherapy based on platinum agents is generally used, regardless of the fact that drug toxicity leads to limited clinical efficacy. In order to overcome these problems, our group has been working on the synthesis and study of trans platinum (II) complexes. Here, we explore the potential use of two phosphine-based agents with the general formula trans-[Pt(amine)Cl2(PPh3)], called P1 and P2 (with dimethylamine or isopropylamine, respectively). A cytotoxicity analysis showed that P1 and especially P2 decrease cell viability. Specifically, P2 exhibits higher activity than cisplatin in gastric cancer cells while its toxicity in healthy cells is slightly lower. Both complexes generate Reactive Oxygen Species, produce DNA damage and mitochondrial membrane depolarization, and finally lead to induced apoptosis. Thus, an intrinsic apoptotic pathway emerges as the main type of cell death through the activation of BAX/BAK and BIM and the degradation of MCL1. Additionally, we demonstrate here that P2 produces endoplasmic reticulum stress and activates the Unfolded Protein Response, which also relates to the impairment observed in autophagy markers such as p62 and LC3. Although further studies in other biological models are needed, these results report the biomolecular mechanism of action of these Pt(II)-phosphine prototypes, thus highlighting their potential as novel and effective therapies.

Prevention of UVB-Induced Photoaging by an Ethyl Acetate Fraction from Allomyrina dichotoma Larvae and Its Potential Mechanisms in Human Dermal Fibroblasts.

Allomyrina dichotoma larvae (ADL) is an insect type that is used ethnopharmacologically to treat various diseases; however, its use as an antiaging treatment has not been widely studied. Previously, we found that an ethyl acetate (EA) fraction derived from an ADL extract (ADLE) has a high polyphenol content and antioxidant properties. In this study, we identified the underlying molecular mechanism for the protective effect of the EA fraction against UVB-induced photodamage in vitro and ex vivo. UVB treatment increased intracellular reactive oxygen species levels and DNA damage; the latter of which was significantly decreased following cotreatment with the EA fraction. Biological markers of aging, such as p16INK4a, p21WAF1, and senescence-associated ß-gal levels, were induced by UVB treatment but significantly suppressed following EA-fraction treatment. UVB-induced upregulation of matrix metalloproteinase (MMP)-1 and downregulation of COL1A1 were also reversed by EA-fraction treatment in both cells and a 3D skin model, which resulted in increased keratin and collagen deposition. Moreover, EA-fraction treatment inhibited the phosphorylation of MAPKs (p38, ERK, and JNK) and nuclear factor (NF-)-kB and decreased the levels of inflammatory cytokines in UVB-treated cells. The results indicate that an EA fraction from ADLE ameliorates UVB-induced degradation of COL1A1 by inhibiting MMP expression and inactivating the MAPK/NF-κB p65/AP-1 signaling pathway involved in this process.

5-aminolevulinic acid photodynamic therapy protects against UVB-induced skin photoaging: A DNA-repairing mechanism involving the BER signalling pathway.

Low-dose 5-aminolevulinic acid photodynamic therapy (ALA-PDT) has been used to cope with skin photoaging, and is thought to involve DNA damage repair responses. However, it is still unknown how low-dose ALA-PDT regulates DNA damage repair to curb skin photoaging. We established a photoaging model using human dermal fibroblasts (HDFs) and rat skin. RNA-sequencing (RNA-seq) analysis was conducted to identify differentially expressed genes (DEGs) in HDFs before and after low-dose ALA-PDT treatment, followed by bioinformatics analysis. Senescence-associated ß-galactosidase (SA-ß-gal) staining was employed to assess skin aging-related manifestations and Western blotting to evaluate the expression of associated proteins. A comet assay was used to detect cellular DNA damage, while immunofluorescence to examine the expression of 8-hydroxy-2'-deoxyguanosine (8-oxo-dG) in cells and skin tissues. In both in vivo and in vitro models, low-dose ALA-PDT alleviated the manifestations of ultraviolet B (UVB)-induced skin photoaging. Low-dose ALA-PDT significantly reduced DNA damage in photoaged HDFs. Furthermore, low-dose ALA-PDT accelerated the clearance of the photoproduct 8-oxo-dG in photoaged HDFs and superficial dermis of photoaged rat skin. RNA-seq analysis suggested that low-dose ALA-PDT upregulated the expression of key genes in the base excision repair (BER) pathway. Further functional validation showed that inhibition on BER expression by using UPF1069 significantly suppressed SA-ß-gal activity, G2/M phase ratio, expression of aging-associated proteins P16, P21, P53, and MUTYH proteins, as well as clearance of the photoproduct 8-oxo-dG in photoaged HDFs. Low-dose ALA-PDT exerts anti-photoaging effects by activating the BER signalling pathway.

H3K27ac acts as a molecular switch for doxorubicin-induced activation of cardiotoxic genes.

BACKGROUND: Doxorubicin (Dox) is an effective chemotherapeutic drug for various cancers, but its clinical application is limited by severe cardiotoxicity. Dox treatment can transcriptionally activate multiple cardiotoxicity-associated genes in cardiomyocytes, the mechanisms underlying this global gene activation remain poorly understood. METHODS AND RESULTS: Herein, we integrated data from animal models, CUT&Tag and RNA-seq after Dox treatment, and discovered that the level of H3K27ac (a histone modification associated with gene activation) significantly increased in cardiomyocytes following Dox treatment. C646, an inhibitor of histone acetyltransferase, reversed Dox-induced H3K27ac accumulation in cardiomyocytes, which subsequently prevented the increase of Dox-induced DNA damage and apoptosis. Furthermore, C646 alleviated cardiac dysfunction in Dox-treated mice by restoring ejection fraction and reversing fractional shortening percentages. Additionally, Dox treatment increased H3K27ac deposition at the promoters of multiple cardiotoxic genes including Bax, Fas and Bnip3, resulting in their up-regulation. Moreover, the deposition of H3K27ac at cardiotoxicity-related genes exhibited a broad feature across the genome. Based on the deposition of H3K27ac and mRNA expression levels, several potential genes that might contribute to Dox-induced cardiotoxicity were predicted. Finally, the up-regulation of H3K27ac-regulated cardiotoxic genes upon Dox treatment is conservative across species. CONCLUSIONS: Taken together, Dox-induced epigenetic modification, specifically H3K27ac, acts as a molecular switch for the activation of robust cardiotoxicity-related genes, leading to cardiomyocyte death and cardiac dysfunction. These findings provide new insights into the relationship between Dox-induced cardiotoxicity and epigenetic regulation, and identify H3K27ac as a potential target for the prevention and treatment of Dox-induced cardiotoxicity.

Tripeptide linked dispiro cyclotriphosphazene conjugates: Synthesis, molecular docking analysis of compounds binding within cancer cell line receptors and in vitro cytotoxic and genotoxic activities.

The novel dioxybiphenyl bridged-cyclotriphosphazenes (DPP) bearing tripeptide were synthesized and investigated for their molecular docking analysis, visualizing their binding profiles within various cancer cell line receptors and in vitro cytotoxic and genotoxic properties. The dipeptide compound (Tyr-Phe) was treated with various amino acids to obtain the tripeptide compounds (Tyr-Phe-Gly, Tyr-Phe-Ala, Tyr-Phe-Val, Tyr-Phe-Phe, and Tyr-Phe-Leu). These synthesized tripeptides were subsequently treated with DPP to obtain novel phosphazene compounds bearing tripeptide structures. As a result, the synthesis of target molecules with phosphazene compound in the center and biphenyl and tripeptide groups in the side arms was obtained for the first time in this study. Examining the cytotoxic studies in vitro of our newly synthesized compounds demonstrated the anticancer properties against four selected human cancer cell lines, including breast (MCF-7), ovarian (A2780), prostate (PC-3), and colon (Caco-2) cancer cells. The Comet Assay analysis determined that the cell death mechanism of most of the compounds with cytotoxic activity stemmed from the DNA damage mechanism. Among the compounds, the DPP-Tyr-Phe-Phe compound seems to have the best anticancer activity against the subjected cell lines (Except for A2780) with IC50 values equal to 20.18, 72.14, 12.21, and 5.17 µM against breast, ovarian, prostate, and colon cancer cell lines, respectively. For this reason, the molecular docking analysis was conducted for the DTPP compound to visualize its binding geometry and profile within the target enzyme's binding site associated with the specific cancer cell line. The analysis revealed that the DTPP derivative exhibited an optimal binding conformation and characteristics within the target enzyme's binding site, aligning well with the experimental data. Based on the data, these compounds are believed to be strong candidate molecules for both pharmaceutical and clinical applications.

Onvansertib treatment overcomes olaparib resistance in high-grade ovarian carcinomas.

Occurrence of resistance to olaparib, a poly(ADP-ribose) polymerase (PARP) inhibitor (PARPi) approved in ovarian carcinoma, has already been shown in clinical settings. Identifying combination treatments to sensitize tumor cells and/or overcome resistance to olaparib is critical. Polo-like kinase 1 (PLK1), a master regulator of mitosis, is also involved in the DNA damage response promoting homologous recombination (HR)-mediated DNA repair and in the recovery from the G2/M checkpoint. We hypothesized that PLK1 inhibition could sensitize tumor cells to PARP inhibition. Onvansertib, a highly selective PLK1 inhibitor, and olaparib were tested in vitro and in vivo in BRCA1 mutated and wild-type (wt) ovarian cancer models, including patient-derived xenografts (PDXs) resistant to olaparib. The combination of onvansertib and olaparib was additive or synergic in different ovarian cancer cell lines, causing a G2/M block of the cell cycle, DNA damage, and apoptosis, much more pronounced in cells treated with the two drugs as compared to controls and single agents treated cells. The combined treatment was well tolerated in vivo and resulted in tumor growth inhibition and a statistically increased survival in olaparib-resistant-BRCA1 mutated models. The combination was also active, although to a lesser extent, in BRCA1 wt PDXs. Pharmacodynamic analyses showed an increase in mitotic, apoptotic, and DNA damage markers in tumor samples derived from mice treated with the combination versus vehicle. We could demonstrate that in vitro onvansertib inhibited both HR and non-homologous end-joining repair pathways and in vivo induced a decrease in the number of RAD51 foci-positive tumor cells, supporting its ability to induce HR deficiency and favoring the activity of olaparib. Considering that the combination was well tolerated, these data support and foster the clinical evaluation of onvansertib with PARPis in ovarian cancer, particularly in the PARPis-resistant setting.

New Horizons of Synthetic Lethality in Cancer: Current Development and Future Perspectives.

In recent years, synthetic lethality has been recognized as a solid paradigm for anticancer therapies. The discovery of a growing number of synthetic lethal targets has led to a significant expansion in the use of synthetic lethality, far beyond poly(ADP-ribose) polymerase inhibitors used to treat BRCA1/2-defective tumors. In particular, molecular targets within DNA damage response have provided a source of inhibitors that have rapidly reached clinical trials. This Perspective focuses on the most recent progress in synthetic lethal targets and their inhibitors, within and beyond the DNA damage response, describing their design and associated therapeutic strategies. We will conclude by discussing the current challenges and new opportunities for this promising field of research, to stimulate discussion in the medicinal chemistry community, allowing the investigation of synthetic lethality to reach its full potential.

The Role of IRF9 Upregulation in Modulating Sensitivity to Olaparib and Platinum-Based Chemotherapies in Breast Cancer.

Poly(ADP-ribose) polymerase (PARP) inhibitors are targeted therapies that accumulate DNA damage by interfering with DNA repair mechanisms and are approved for treating several cancers with BRCA1/2 mutations. In this study, we utilized CRISPR-dCas9 interference screening to identify genes regulating sensitivity to PARP inhibitors in breast cancer cell lines. Our findings indicated that the interferon (IFN) signaling gene IRF9 was critically involved in modulating sensitivity to these inhibitors. We revealed that the loss of IRF9 leads to increased resistance to the PARP inhibitor in MDA-MB-468 cells, and a similar desensitization was observed in another breast cancer cell line, MDA-MB-231. Further analysis indicated that while the basal expression of IRF9 did not correlate with the response to the PARP inhibitor olaparib, its transcriptional induction was significantly associated with increased sensitivity to the DNA-damaging agent cisplatin in the NCI-60 cell line panel. This finding suggests a mechanistic link between IRF9 induction and cellular responses to DNA damage. Additionally, data from the METABRIC patient tissue study revealed a complex network of IFN-responsive gene expressions postchemotherapy, with seven upregulated genes, including IRF9, and three downregulated genes. These findings underscore the intricate role of IFN signaling in the cellular response to chemotherapy. Collectively, our CRISPR screening data and subsequent bioinformatic analyses suggest that IRF9 is a novel biomarker for sensitivity to DNA-damaging agents, such as olaparib and platinum-based chemotherapeutic agents. Our findings for IRF9 not only enhance our understanding of the genetic basis of drug sensitivity, but also elucidate the role of IRF9 as a critical effector within IFN signaling pathways, potentially influencing the association between the host immune system and chemotherapeutic efficacy.

The Induction of G2/M Phase Cell Cycle Arrest and Apoptosis by the Chalcone Derivative 1C in Sensitive and Resistant Ovarian Cancer Cells Is Associated with ROS Generation.

Ovarian cancer ranks among the most severe forms of cancer affecting the female reproductive organs, posing a significant clinical challenge primarily due to the development of resistance to conventional therapies. This study investigated the effects of the chalcone derivative 1C on sensitive (A2780) and cisplatin-resistant (A2780cis) ovarian cancer cell lines. Our findings revealed that 1C suppressed cell viability, induced cell cycle arrest at the G2/M phase, and triggered apoptosis in both cell lines. These effects are closely associated with generating reactive oxygen species (ROS). Mechanistically, 1C induced DNA damage, modulated the activity of p21, PCNA, and phosphorylation of Rb and Bad proteins, as well as cleaved PARP. Moreover, it modulated Akt, Erk1/2, and NF-κB signaling pathways. Interestingly, we observed differential effects of 1C on Nrf2 levels between sensitive and resistant cells. While 1C increased Nrf2 levels in sensitive cells after 12 h and decreased them after 48 h, the opposite effect was observed in resistant cells. Notably, most of these effects were suppressed by the potent antioxidant N-acetylcysteine (NAC), underscoring the crucial role of ROS in 1C-induced antiproliferative activity. Moreover, we suggest that modulation of Nrf2 levels can, at least partially, contribute to the antiproliferative effect of chalcone 1C.