Oxidative Damage as a Fundament of Systemic Toxicities Induced by Cisplatin-The Crucial Limitation or Potential Therapeutic Target?

Taxifolin mitigates cisplatin-induced testicular damage by reducing inflammation, oxidative stress, and apoptosis in mice

Cisplatin (CIS) is effective against various cancers but causes significant side effects, including testicular damage. This study investigated the effects of taxifolin (TX), a potent flavonoid with well-known benefits, against CIS-induced testicular injury. Mice received TX (25 and 50 mg/kg) orally for 14 days, with a single injection of CIS (7 mg/kg) on day 8. CIS significantly impaired sperm parameters (motility, viability, and count) and caused notable histopathological alterations in testicular tissue. CIS-treated testicular tissue exhibited elevated MDA and protein carbonyl levels, alongside decreased antioxidant defenses, including GSH, SOD, and catalase activities. TX significantly mitigated the deterioration of sperm parameters and prevented testicular tissue damage. It also restored antioxidant levels and reduced MDA and protein carbonyl contents. Furthermore, CIS elevated pro-inflammatory markers (NF-κB p65, TNF-α, and IL-1β) and apoptosis markers (Bax and caspase-3), while reducing anti-apoptotic Bcl-2 levels. TX effectively suppressed NF-κB activation, reduced pro-inflammatory cytokine production, and inhibited apoptosis in CIS-treated mice. Overall, TX alleviated CIS-induced oxidative stress, inflammation, apoptosis, and testicular damage, thereby improving sperm quality. These findings emphasize TX's potential as a protective agent against CIS-induced testicular damage and warrant further research in human applications.

Protective effect of adenosine triphosphate against cisplatin-induced necrotic and degenerative oral mucositis in rats

BACKGROUND

Inflammation, oxidative damage, and adenosine triphosphate (ATP) depletion play a role in the pathogenesis of cisplatin (CIS)-induced oral mucositis.

OBJECTIVE

The purpose of this research is to examine the impact of ATP against potential oral mucositis development in cisplatin-treated rats. Methodology All rats were randomly assigned to four groups, namely healthy control group (HG), ATP group (ATPG), Cisplatin group (CISG), and ATP + Cisplatin group (ATCS). Firstly, ATP 4 mg/kg was administered via intraperitoneal injection (IP) to both ATPG and ATCS groups. The same volume of normal saline was injected into HG and CISG groups. After 1 h, cisplatin 5 mg/kg was administered via IP to CISG and ATCS groups. The drugs were taken 1x1 for 7 d. Later, tongue tissues were collected from all groups. Biochemical, macroscopic, and histopathological examinations were performed on all tissues.

RESULTS

ATP inhibited cisplatin-induced oxidative damage and pro-inflammatory cytokines levels in tongue tissue. In the CIS group, a significant number of distinct sulcus formations were found in the apex and corpus, as well as a few ulcer foci in the corpus, significant papilla loss, and bleeding. Meanwhile, in the ATP group, a similar appearance to healthy tissue was observed. Histopathologically, it was determined that in cisplatin-aggravated tongue tissue damage, filiform papillae decreased when ATP was administered, and the arrangement and structures of the epithelium, blood capillaries, muscle groups, and adipose cell groups were normal.

CONCLUSIONS

Oral mucositis caused by cisplatin is alleviated by ATP. These findings may be useful for developing new therapeutic approaches to prevent or treat mucositis, a side effect so severe that can lead to treatment discontinuation.

Development of a Prognostic Risk Model Based on Oxidative Stress-related Genes for Platinum-resistant Ovarian Cancer Patients

INTRODUCTION

Ovarian Cancer (OC) is a heterogeneous malignancy with poor outcomes. Oxidative stress plays a crucial role in developing drug resistance. However, the relationships between Oxidative Stress-related Genes (OSRGs) and the prognosis of platinum-resistant OC remain unclear. This study aimed to develop an OSRGs-based prognostic risk model for platinum- resistant OC patients.

METHODS

Gene Set Enrichment Analysis (GSEA) was performed to determine the expression difference of OSRGs between platinum-resistant and -sensitive OC patients. Cox regression analyses were used to identify the prognostic OSRGs and establish a risk score model. The model was validated by using an external dataset. Machine learning was used to determine the prognostic OSRGs associated with platinum resistance. Finally, the biological functions of selected OSRG were determined via in vitro cellular experiments.

RESULTS

Three gene sets associated with oxidative stress-related pathways were enriched (p < 0.05), and 105 OSRGs were found to be differentially expressed between platinum-resistant and - sensitive OC (p < 0.05). Twenty prognosis-associated OSRGs were identified (HR: 0:562-5.437; 95% CI: 0.319-20.148; p < 0.005), and seven independent OSRGs were used to construct a prognostic risk score model, which accurately predicted the survival of OC patients (1-, 3-, and 5-year AUC=0.69, 0.75, and 0.67, respectively). The prognostic potential of this model was confirmed in the validation cohort. Machine learning showed five prognostic OSRGs (SPHK1, PXDNL, C1QA, WRN, and SETX) to be strongly correlated with platinum resistance in OC patients. Cellular experiments showed that WRN significantly promoted the malignancy and platinum resistance of OC cells.

CONCLUSION

The OSRGs-based risk score model can efficiently predict the prognosis and platinum resistance of OC patients. This model may improve the risk stratification of OC patients in the clinic.

OTULIN confers cisplatin resistance in osteosarcoma by mediating GPX4 protein homeostasis to evade the mitochondrial apoptotic pathway

BACKGROUND

Osteosarcoma (OS), the most prevalent primary malignant bone tumor in children and adolescents, arises from bone-forming mesenchymal cells. Despite advancements in surgical resection and neoadjuvant chemotherapy (cisplatin, doxorubicin, and methotrexate), chemotherapy resistance remains a significant challenge, leading to poor survival rates in patients with metastatic or recurrent OS.

METHODS

In this study, we focused on the role of OTULIN, a key linear deubiquitinating enzyme, in OS chemoresistance. In addition, mechanistic investigations were carried out to identify potential downstream targets of OTULIN involved in cisplatin resistance.

RESULTS

Our results demonstrated that OTULIN expression was significantly upregulated in OS tissues and cell lines following cisplatin treatment but not in response to doxorubicin or methotrexate. High OTULIN expression was associated with reduced survival in sarcoma patients. Furthermore, immunohistochemical analysis of prechemotherapy and postchemotherapy OS tissues revealed increased OTULIN expression in postchemotherapy samples. In vitro results demonstrated that OTULIN plays a critical role in mediating cisplatin resistance in OS. Mechanistically, GPX4 could be a downstream target of OTULIN, conferring cisplatin resistance to OS by blocking the mitochondrial apoptotic pathway but not ferroptosis. Specifically, OTULIN prevents the proteasomal degradation of GPX4 by reducing its ubiquitin level, thereby conferring resistance to cisplatin in OS cells.

CONCLUSION

This study highlights the importance of OTULIN in OS chemoresistance and provides a promising approach for targeting the OTULIN-GPX4 axis to improve the prognosis of OS patients. Our findings offer new insights into the molecular mechanisms underlying OS chemoresistance and suggest potential therapeutic targets for future clinical interventions.

Cisplatin-Induced Hearing Loss, Oxidative Stress, and Antioxidants as a Therapeutic Strategy-A State-of-the-Art Review

Cisplatin is an established component of treatment protocols for various solid malignancies but carries a significant potential for serious adverse effects. Ototoxicity from cisplatin treatment is an important dose-limiting toxicity that manifests as bilateral, progressive, irreversible, dose-dependent sensorineural hearing loss, ear pain, tinnitus, and vestibular dysfunction. Despite the recent approval of sodium thiosulphate for the prevention of cisplatin-induced hearing loss (CIHL) in pediatric patients, structured prevention programs are not routinely implemented in most hospitals, and reducing platinum-induced ototoxicity in adults remains an important clinical problem without established treatment options. Cochlear oxidative stress plays a fundamental role in CIHL. Here, we review the molecular mechanisms leading to oxidative stress in CIHL and the clinical and preclinical studies testing antioxidants in CIHL to guide future clinical trials in assessing the efficacy and safety of candidate antioxidant compounds in this clinical setting.

Advances in understanding cisplatin-induced toxicity: Molecular mechanisms and protective strategies

Cisplatin, a widely used chemotherapeutic agent, has proven efficacy against various malignancies. However, its clinical utility is hampered by its dose-limiting toxicities, including nephrotoxicity, ototoxicity, neurotoxicity, and myelosuppression. This review aims to provide a comprehensive overview of cisplatin toxicity, encompassing its underlying mechanisms, risk factors, and emerging therapeutic strategies. The mechanisms of cisplatin toxicity are multifactorial and involve oxidative stress, inflammation, DNA damage, and cellular apoptosis. Various risk factors contribute to the interindividual variability in susceptibility to cisplatin toxicity. The risk of developing cisplatin-induced toxicity could be related to pre-existing conditions, including kidney disease, hearing impairment, neuropathy, impaired liver function, and other comorbidities. Additionally, this review highlights the emerging therapeutic strategies that could be applied to minimize cisplatin-induced toxicities and aid in optimizing cisplatin treatment regimens, improving patient outcomes, and enhancing the overall quality of cancer care.

Chokeberry Products and By-Products as the Potential Pharmaceuticals for Kidney Protection-An Experimental Study in Rats

The study aimed to investigate the protective effects of chokeberry fruit products and by-products against cisplatin-induced acute nephrotoxicity in rats. Potential mechanisms involving oxidative stress and inflammatory responses were examined through biochemical and histopathological analyses of kidney tissue. Chokeberry waste, along with the whole fruit extract and juice, was evaluated as a potential raw material for pharmaceutical use. The chemical composition of chokeberry juice and extracts was analyzed using spectrophotometry and HPLC. Rats were treated with chokeberry preparations via intragastric tube for ten days, with a single intraperitoneal dose of cisplatin (8 mg/kg BW) administered on the third day. Post-sacrifice, plasma samples were analyzed for biochemical nephrotoxicity markers, oxidative stress, and inflammatory markers. Kidneys were removed for histopathological and biochemical analysis. Cisplatin-induced acute nephrotoxicity was confirmed by elevated plasma creatinine and blood urea nitrogen levels. Additionally, lipid peroxidation was significantly elevated, while reduced glutathione and catalase activity were significantly reduced. Pro-inflammatory mediators IL-1β, TNF-α, and IL-6 levels were significantly increased in the cisplatin group. Treatment with chokeberry extracts and juice significantly mitigated these nephrotoxic effects, as confirmed by histopathological examination and biochemical marker analysis. Notably, the waste extract demonstrated greater efficacy than the whole fruit extract, likely due to its higher concentration of polyphenolic compounds, especially anthocyanins. These results highlight the potential of chokeberry as a therapeutic and preventive agent for kidney protection, emphasizing the value of by-products rich in biologically active compounds.

Natural products for enhancing the sensitivity or decreasing the adverse effects of anticancer drugs through regulating the redox balance

Redox imbalance is reported to play a pivotal role in tumorigenesis, cancer development, and drug resistance. Severe oxidative damage is a general consequence of cancer cell responses to treatment and may cause cancer cell death or severe adverse effects. To maintain their longevity, cancer cells can rescue redox balance and enter a state of resistance to anticancer drugs. Therefore, targeting redox signalling pathways has emerged as an attractive and prospective strategy for enhancing the efficacy of anticancer drugs and decreasing their adverse effects. Over the past few decades, natural products (NPs) have become an invaluable source for developing new anticancer drugs due to their high efficacy and low toxicity. Increasing evidence has demonstrated that many NPs exhibit remarkable antitumour effects, whether used alone or as adjuvants, and are emerging as effective approaches to enhance sensitivity and decrease the adverse effects of conventional cancer therapies by regulating redox balance. Among them are several novel anticancer drugs based on NPs that have entered clinical trials. In this review, we summarize the synergistic anticancer effects and related redox mechanisms of the combination of NPs with conventional anticancer drugs. We believe that NPs targeting redox regulation will represent promising novel candidates and provide prospects for cancer treatment in the future.

The Effect of Thymoquinone on the TNF-α/OTULIN/NF-κB Axis Against Cisplatin-İnduced Testicular Tissue Damage

One of the adverse effects of the antineoplastic drug cisplatin (CS) is damage to testicular tissue. This study aimed to examine the potential therapeutic effect of thymoquinone (TQ), a strong antioxidant, against testicular damage caused by CS. In the experiment, 28 rats were used, and the rats were randomly divided into four groups: control (n = 7), CS (n = 7), CS + TQ (n = 7), and TQ (n = 7). The experiment was called off after all treatments were finished on day 15. Blood serum and testicular tissues were utilized for biochemical, histological, immunohistochemical, mRNA expression, and gene protein investigations. The testosterone level decreased and oxidative stress, histopathological damage, dysregulation in mitochondrial dynamics, inflammation and apoptotic cells increased in testicular tissue due to CS administration. TQ supplementation showed anti-inflammatory, antioxidant, and anti-apoptotic effects in response to CS-induced testicular damage. In addition, TQ contributed to the reduction of CS-induced toxic effects by regulating the TNF-α/OTULIN/NF-κB pathway. TQ supplementation may be a potential therapeutic strategy against CS-induced testicular damage by regulating the TNF-α/OTULIN/NF-κB axis, inhibiting inflammation, oxidative stress, and apoptosis.

hTERT Epigenetics Provides New Perspectives for Diagnosis and Evidence-Based Guidance of Chemotherapy in Cancer

Strong epigenetic pan-cancer biomarkers are required to meet several current, urgent clinical needs and to further improve the present chemotherapeutic standard. We have concentrated on the investigation of epigenetic alteration of the hTERT gene, which is frequently epigenetically dysregulated in a number of cancers in specific developmental stages. Distinct DNA methylation profiles were identified in our data on early urothelial cancer. An efficient EpihTERT assay could be developed utilizing suitable combinations with sequence-dependent thermodynamic parameters to distinguish between differentially methylated states. We infer from this data set, the epigenetic context, and the related literature that a CpG-rich, 2800 bp region, a prominent CpG island, surrounding the transcription start of the hTERT gene is the crucial epigenetic zone for the development of a potent biomarker. In order to accurately describe this region, we have named it "Acheron" (Ἀχέρων). In Greek mythology, this is the river of woe and misery and the path to the underworld. Exploitation of the DNA methylation profiles focused on this region, e.g., idiolocal normalized Methylation Specific PCR (IDLN-MSP), opens up a wide range of new possibilities for diagnosis, determination of prognosis, follow-up, and detection of residual disease. It may also have broad implications for the choice of chemotherapy.

Malate, a natural inhibitor of 6PGD, improves the efficacy of chemotherapy in lung cancer

OBJECTIVE

Metabolic reprogramming is an important coordinator of tumor development and resistance to therapy, such as the tendency of tumor cells to utilize glycolytic energy rather than oxidative phosphorylation, even under conditions of sufficient oxygen. Therefore, targeting metabolic enzymes is an effective strategy to overcome therapeutic resistance.

MATERIALS AND METHODS

We explored the differential expression and growth-promoting function of MDH2 by immunohistochemistry and immunoblotting experiments in lung cancer patients and lung cancer cells. Pentose phosphate pathway-related phenotypes (including ROS levels, NADPH levels, and DNA synthesis) were detected intracellularly, and the interaction of malate and proteinase 6PGD was detected in vitro. In vivo experiments using implanted xenograft mouse models to explore the growth inhibitory effect and pro-chemotherapeutic function of dimethyl malate (DMM) on lung cancer.

RESULTS

We found that the expression of malate dehydrogenase (MDH2) in the tricarboxylic acid cycle (TCA cycle) was increased in lung cancer. Biological function enrichment analysis revealed that MDH2 not only promoted oxidative phosphorylation, but also promoted the pentose phosphate pathway (PPP pathway). Mechanistically, it was found that malate, the substrate of MDH2, can bind to the PPP pathway metabolic enzyme 6PGD, inhibit its activity, reduce the generation of NADPH, and block DNA synthesis. More importantly, DMM can improve the sensitivity of lung cancer to the clinical drug cisplatin.

CONCLUSION

We have identified malate as a natural inhibitor of 6PGD, which will provide new leads for the development of 6PGD inhibitors. In addition, the metabolic enzyme MDH2 and the metabolite malate may provide a backup option for cells to inhibit their own carcinogenesis, as the accumulated malate targets 6PGD to block the PPP pathway and inhibit cell cycle progression.

The uses of zebrafish (Danio rerio) as an in vivo model for toxicological studies: A review based on bibliometrics

An in vivo model is necessary for toxicology. This review analyzed the uses of zebrafish (Danio rerio) in toxicology based on bibliometrics. Totally 56,816 publications about zebrafish from 2002 to 2023 were found in Web of Science Core Collection, with Toxicology as the top 6 among all disciplines. Accordingly, the bibliometric map reveals that "toxicity" has become a hot keyword. It further reveals that the most common exposure types include acute, chronic, and combined exposure. The toxicological effects include behavioral, intestinal, cardiovascular, hepatic, endocrine toxicity, neurotoxicity, immunotoxicity, genotoxicity, and reproductive and transgenerational toxicity. The mechanisms include oxidative stress, inflammation, autophagy, and dysbiosis of gut microbiota. The toxicants commonly evaluated by using zebrafish model include nanomaterials, arsenic, metals, bisphenol, and dioxin. Overall, zebrafish provide a unique and well-accepted model to investigate the toxicological effects and mechanisms. We also discussed the possible ways to address some of the limitations of zebrafish model, such as the combination of human organoids to avoid species differences.