Unravelling the metabolic rewiring in the context of doxorubicin-induced cardiotoxicity: Fuel preference changes from fatty acids to glucose oxidation.

Doxorubicin (DOX) is a highly effective chemotherapeutic agent whose clinical use is hindered by the onset of cardiotoxic effects, resulting in reduced ejection fraction within the first year from treatment initiation. Recently it has been demonstrated that DOX accumulates within mitochondria, leading to disruption of metabolic processes and energetic imbalance. We previously described that phosphoinositide 3-kinase γ (PI3Kγ) contributes to DOX-induced cardiotoxicity, causing autophagy inhibition and accumulation of damaged mitochondria. Here we intend to describe the maladaptive metabolic rewiring occurring in DOX-treated hearts and the contribution of PI3Kγ signalling to this process. Metabolomic analysis of DOX-treated WT hearts revealed an accumulation of TCA cycle metabolites due to a cycle slowdown, with reduced levels of pyruvate, unchanged abundance of lactate and increased Acetyl-CoA production. Moreover, the activity of glycolytic enzymes was upregulated, and fatty acid oxidation downregulated, after DOX, indicative of increased glucose oxidation. In agreement, oxygen consumption was increased in after pyruvate supplementation, with the formation of cytotoxic ROS rather than energy production. These metabolic changes were fully prevented in KD hearts. Interestingly, they failed to increase glucose oxidation in response to DOX even with autophagy inhibition, indicating that PI3Kγ likely controls the fuel preference after DOX through an autophagy-independent mechanism. In vitro experiments showed that inhibition of PI3Kγ inhibits pyruvate dehydrogenase (PDH), the key enzyme of Randle cycle regulating the switch from fatty acids to glucose usage, while decreasing DOX-induced mobilization of GLUT-4-carrying vesicles to the plasma membrane and limiting the ensuing glucose uptake. These results demonstrate that PI3Kγ promotes a maladaptive metabolic rewiring in DOX-treated hearts, through a two-pronged mechanism controlling PDH activation and GLUT-4-mediated glucose uptake.

SNX3 Promotes Doxorubicin-Induced Cardiomyopathy by Regulating GPX4-Mediated Ferroptosis.

The complete molecular mechanism underlying doxorubicin-induced cardiomyopathy remains incompletely elucidated. In this investigation, we engineered mice with cardiomyocyte-specific sorting nexin 3 knockout (SNX3Cko ) to probe the potential protective effects of SNX3 ablation on doxorubicin-triggered myocardial injury, focusing on GPX4-dependent ferroptosis. Our findings indicate that SNX3 deletion normalized heart contractile/relaxation function and thwarted the escalation of cardiac injury biomarkers following doxorubicin exposure. Additionally, SNX3 deletion in the heart mitigated the inflammatory response and oxidative stress in the presence of doxorubicin. At the molecular level, the detrimental effects of doxorubicin-induced cell death, endoplasmic reticulum (ER) stress, and mitochondrial dysfunction were alleviated by SNX3 deficiency. Molecular analysis revealed the activation of GPX4-mediated ferroptosis by doxorubicin, whereas loss of SNX3 prevented the initiation of GPX4-dependent ferroptosis. Furthermore, treatment with erastin, a ferroptosis inducer, markedly reduced cell viability, exacerbated ER stress, and induced mitochondrial dysfunction in SNX3-depleted cardiomyocytes upon doxorubicin exposure. In summary, our results demonstrate that SNX3 deficiency shielded the heart from doxorubicin-induced myocardial dysfunction by modulating GPX4-associated ferroptosis.

Amantadine mitigates the cytotoxic and genotoxic effects of doxorubicin in SH-SY5Y cells and reduces its mutagenicity.

Amantadine (AMA) is a useful drug in neuronal disorders, but few studies have been performed to access its toxicological profile. Conversely, doxorubicin (Dox) is a well-known antineoplastic drug that has shown neurotoxic effects leading to cognitive impairment. The aims of this study are to evaluate the cytotoxic, genotoxic, and mutagenic effects of AMA, as well as its possible protective actions against deleterious effects of Dox. The Salmonella/microsome assay was performed to assess mutagenicity while cytotoxicity and genotoxicity were evaluated in SH-SY5Y cells using MTT and comet assays. Possible modulating effects of AMA on the cytotoxicity, genotoxicity, and mutagenicity induced by Dox were evaluated through cotreatment procedures. Amantadine did not induce mutations in the Salmonella/microsome assay and decreased Dox-induced mutagenicity in the TA98 strain. AMA reduced cell viability and induced DNA damage in SH-SY5Y cells. In cotreatment with Dox, AMA attenuated the cytotoxicity of Dox and showed an antigenotoxic effect. In conclusion, AMA does not induce gene mutations, although it has shown a genotoxic effect. Furthermore, AMA decreases frameshift mutations induced by Dox as well as the cytotoxic and genotoxic effects of Dox in SH-SY5Y cells, suggesting that AMA can interfere with Dox mutagenic activity and attenuate its neurotoxic effects.

Ultrasonographic and histopathological investigation of the effect of N-acetylcysteine on doxorubicin-induced ovarian and uterine toxicity in rats.

BACKGROUND: This study aimed to investigate the mitigating effect of N-acetylcysteine (NAC) on doxorubicin (DOX)-induced ovarian and uterine toxicity in rats using laboratory tests, ultrasonographic (US) imaging, and histopathology analysis. METHODS: Forty-eight rats were divided into six groups (n = 8) as follows: Group A (control) (0.5 mL saline administered intraperitoneally [IP]), Group B (a single 10 mg/kg dose of DOX administered IP on day 1), Group C (a single 10 mg/kg dose of DOX administered IP 24 h before sacrifice), Group D (100 mg/kg of NAC administered IP for 21 days), Group E ( a single 10 mg/kg dose of DOX administered IP on day 1 and 100 mg/kg of NAC administered IP for 21 days), and Group F (100 mg/kg of NAC administered IP for 21 days and a single 10 mg/kg dose of DOX administered IP 24 h before sacrifice). The ovaries were examined using B-mode US on days 1, 14, and 21, and the histopathological examinations of the ovaries and the uterus were undertaken after sacrifice on day 22. RESULTS: Histomorphological analyses showed that ovarian weight decreased after DOX administration in Group B but not in Group E. US revealed a transient increase in ovarian size in Group B and E, reverting to baseline levels over time, as well as a progressive increase in peritoneal fluid in Groups B and E. Group B exhibited a significant decrease in the thickness of the endometrium and myometrium and uterine cornual length, which was not observed in Group E. Histopathological examination showed that DOX caused a decline in follicular count, especially in primordial, secondary, and Graafian follicles, and resulted in follicular atresia, predominantly in Group B. Destructive degeneration/necrosis and vascular changes were most prominently seen in the corpus luteum of Groups C and B. In NAC-treated rats (Groups E and F), although germ cell damage was present, atretic follicles and vascular changes, such as hyperemia and congestion, were reduced. The anti-müllerian hormone (AMH) level was the highest in Group F. CONCLUSIONS: NAC, an antioxidant, attenuated DOX-induced gonadotoxicity in rats.

Cuproptosis associated cytoskeletal destruction contributes to podocyte injury in chronic kidney disease.

The podocyte cytoskeleton determines the stability of podocyte structure and function, and their imbalance plays a pathogenic role in podocyte diseases. However, the underlying mechanism of podocyte cytoskeleton damage is not fully understood. Here, we investigate the specific role of cuproptosis in inducing podocyte cytoskeleton injury. In in vitro and in vivo studies, exposure to high levels of copper and adriamycin (ADR) caused significant increases in copper concentration in intracellular and renal tissue. Moreover, excessive accumulation of copper induced cuproptosis, resulting in the destruction of the podocyte cytoskeleton. However, inhibition of copper accumulation to reduce cuproptosis also significantly alleviated the damage of podocyte cytoskeleton. In addition, inhibition of cuproptosis mitigated ADR-induced mitochondrial damage as well as the production of reactive oxygen species and depolarization of mitochondrial membrane potential, and restored adenosine triphosphate (ATP) synthesis. Among the transcriptome sequencing data, the difference of CXCL5 (C-X-C motif chemokine ligand 5) was the most significant. Both high copper and ADR exposure can cause upregulation of CXCL5, and CXCL5 deletion inhibits the occurrence of cuproptosis, thereby alleviating the podocyte cytoskeleton damage. This suggests that CXCL5 may act upstream of cuproptosis that mediates podocyte cytoskeleton damage. In conclusion, cuproptosis induced by excessive copper accumulation may induce podocyte cytoskeleton damage by promoting mitochondrial dysfunction, thereby causing podocyte injury. This indicates that cuproptosis plays an important role in the pathogenesis of podocyte injury and provides a basis for seeking potential targets for the treatment of chronic kidney disease.NEW & NOTEWORTHY Cuproptosis induced by excessive copper accumulation leads to podocyte cytoskeleton damage by promoting mitochondrial dysfunction, and CXCL5 acts as an upstream signal mediating the occurrence of cuproptosis.

Cardioprotective potentials of myricetin on doxorubicin-induced cardiotoxicity based on biochemical and transcriptomic analysis.

Doxorubicin (DOX) is a commonly used anthracycline in cancer chemotherapy. The clinical application of DOX is constrained by its cardiotoxicity. Myricetin (MYR) is a natural flavonoid widely present in many plants with antioxidant and anti-inflammatory properties. However, MYR's beneficial effects and mechanisms in alleviating DOX-induced cardiotoxicity (DIC) remain unknown. C57BL/6 mice were injected with 15 mg/kg of DOX to establish the DIC, and MYR solutions were administrated by gavage to investigate its cardioprotective potentials. Histopathological analysis, physiological indicators assessment, transcriptomics analysis, and RT-qPCR were used to elucidate the potential mechanism of MYR in DIC treatment. MYR reduced cardiac injury produced by DOX, decreased levels of cTnI, AST, LDH, and BNP, and improved myocardial injury and fibrosis. MYR effectively prevented DOX-induced oxidative stress, such as lowered MDA levels and elevated SOD, CAT, and GSH activities. MYR effectively suppressed NLRP3 and ASC gene expression levels to inhibit pyroptosis while regulating Caspase1 and Bax levels to reduce cardiac cell apoptosis. According to the transcriptomic analysis, glucose and fatty acid metabolism were associated with differential gene expression. KEGG pathway analysis revealed differential gene enrichment in PPAR and AMPK pathways, among others. Following validation, MYR was found to alleviate DIC by regulating glycolipid metabolism and AMPK pathway-related genes. Our findings demonstrated that MYR could mitigate DIC by regulating the processes of oxidative stress, apoptosis, and pyroptosis. MYR is critical in improving DOX-induced myocardial energy metabolism abnormalities mediated by the AMPK signaling pathway. In conclusion, MYR holds promise as a therapeutic strategy for DIC.

miRNA Expression Profiles in Isolated Ventricular Cardiomyocytes: Insights into Doxorubicin-Induced Cardiotoxicity.

Doxorubicin (DOX), widely used as a chemotherapeutic agent for various cancers, is limited in its clinical utility by its cardiotoxic effects. Despite its widespread use, the precise mechanisms underlying DOX-induced cardiotoxicity at the cellular and molecular levels remain unclear, hindering the development of preventive and early detection strategies. To characterize the cytotoxic effects of DOX on isolated ventricular cardiomyocytes, focusing on the expression of specific microRNAs (miRNAs) and their molecular targets associated with endogenous cardioprotective mechanisms such as the ATP-sensitive potassium channel (KATP), Sirtuin 1 (SIRT1), FOXO1, and GSK3ß. We isolated Guinea pig ventricular cardiomyocytes by retrograde perfusion and enzymatic dissociation. We assessed cell morphology, Reactive Oxygen Species (ROS) levels, intracellular calcium, and mitochondrial membrane potential using light microscopy and specific probes. We determined the miRNA expression profile using small RNAseq and validated it using stem-loop qRT-PCR. We quantified mRNA levels of some predicted and validated molecular targets using qRT-PCR and analyzed protein expression using Western blot. Exposure to 10 µM DOX resulted in cardiomyocyte shortening, increased ROS and intracellular calcium levels, mitochondrial membrane potential depolarization, and changes in specific miRNA expression. Additionally, we observed the differential expression of KATP subunits (ABCC9, KCNJ8, and KCNJ11), FOXO1, SIRT1, and GSK3ß molecules associated with endogenous cardioprotective mechanisms. Supported by miRNA gene regulatory networks and functional enrichment analysis, these findings suggest that DOX-induced cardiotoxicity disrupts biological processes associated with cardioprotective mechanisms. Further research must clarify their specific molecular changes in DOX-induced cardiac dysfunction and investigate their diagnostic biomarkers and therapeutic potential.

Dihydroartemisinin alleviates doxorubicin-induced cardiotoxicity and ferroptosis by activating Nrf2 and regulating autophagy.

Although the use of Doxorubicin (Dox) is extensive in the treatment of malignant tumor, the toxic effects of Dox on the heart can cause myocardial injury. Therefore, it is necessary to find an alternative drug to alleviate the Dox-induced cardiotoxicity. Dihydroartemisinin (DHA) is a semisynthetic derivative of artemisinin, which is an active ingredient of Artemisia annua. The study investigates the effects of DHA on doxorubicin-induced cardiotoxicity and ferroptosis, which are related to the activation of Nrf2 and the regulation of autophagy. Different concentrations of DHA were administered by gavage for 4 weeks in mice. H9c2 cells were pretreated with different concentrations of DHA for 24 h in vitro. The mechanism of DHA treatment was explored through echocardiography, biochemical analysis, real-time quantitative PCR, western blotting analysis, ROS/DHE staining, immunohistochemistry, and immunofluorescence. In vivo, DHA markedly relieved Dox-induced cardiac dysfunction, attenuated oxidative stress, alleviated cardiomyocyte ferroptosis, activated Nrf2, promoted autophagy, and improved the function of lysosomes. In vitro, DHA attenuated oxidative stress and cardiomyocyte ferroptosis, activated Nrf2, promoted clearance of autophagosomes, and reduced lysosomal destruction. The changes of ferroptosis and Nrf2 depend on selective degradation of keap1 and recovery of lysosome. We found for the first time that DHA could protect the heart from the toxic effects of Dox-induced cardiotoxicity. In addition, DHA significantly alleviates Dox-induced ferroptosis through the clearance of autophagosomes, including the selective degradation of keap1 and the recovery of lysosomes.

Effects of exercise and doxorubicin on acute diaphragm neuromuscular transmission failure.

Doxorubicin (DOX) is a highly effective anthracycline antibiotic used to treat a wide variety of cancers including breast cancer, leukemia and lymphoma. Unfortunately, clinical use of DOX is limited due to adverse off-target effects resulting in fatigue, respiratory muscle weakness and dyspnea. The diaphragm is the primary muscle of inspiration and respiratory insufficiency is likely the result of both muscle weakness and neural impairment. However, the contribution of neuropathology to DOX-induced respiratory muscle dysfunction is unclear. We hypothesized that diaphragm weakness following acute DOX exposure is associated with neurotoxicity and that exercise preconditioning is sufficient to improve diaphragm muscle contractility by maintaining neuromuscular integrity. Adult female Sprague-Dawley rats were randomized into four experimental groups: 1) sedentary-saline, 2) sedentary-DOX, 3) exercise-saline or 4) exercise-DOX. Endurance exercise preconditioning consisted of treadmill running for 1 h/day at 30 m/min for 10 days. Twenty-four hours after the last bout of exercise, animals were treated with DOX (20 mg/kg, I.P.) or saline (equal volume). Our results demonstrate that 48-h following DOX administration diaphragm muscle specific force is reduced in sedentary-DOX rats in response to both phrenic nerve and direct diaphragm stimulation. Importantly, endurance exercise preconditioning in DOX-treated rats attenuated the decrease in diaphragm contractile function, reduced neuromuscular transmission failure and altered phrenic nerve morphology. These changes were associated with an exercise-induced reduction in circulating biomarkers of inflammation, nerve injury and reformation. Therefore, the results are consistent with exercise preconditioning as an effective way of reducing respiratory impairment via preservation of phrenic-diaphragm neuromuscular conduction.

Donepezil ameliorates gut barrier disruption in doxorubicin-treated rats.

An impact of donepezil against doxorubicin-induced gut barrier disruption and gut dysbiosis has never been investigated. Twenty-four male Wistar rats were divided into three groups. Each group was treated with either vehicle as a control, doxorubicin, or doxorubicin-cotreated with donepezil. Heart rate variability was assessed to reflect the impact of doxorubicin and donepezil. Then, animals were euthanized, and the ileum and its contents were collected in each case to investigate the gut barrier and gut microbiota, respectively. The microbiota-derived endotoxin, trimethylamine N-oxide (TMAO), and short-chain fatty acids (SCFAs) in the serum were determined. An increase in the sympathetic tone, endotoxins, and TMAO levels with disruption of the gut barrier and a decrease in SCFAs levels were observed in doxorubicin-treated rats. Gut microbiota of doxorubicin-treated rats was significantly different from that of the control group. Donepezil treatment significantly decreased the sympathetic tone, restored the gut barrier, and reduced endotoxin and TMAO levels in doxorubicin-treated rats. Nonetheless, donepezil administration did not alter the gut microbiota profile and levels of SCFAs in doxorubicin-treated rats. Doxorubicin impaired the autonomic balance and the gut barrier, and induced gut dysbiosis, resulting in gut toxicity. Donepezil partially improved the doxorubicin-induced gut toxicity through balancing the autonomic disturbance.

Beneficial Effects of Oral Carbon Monoxide on Doxorubicin-Induced Cardiotoxicity.

BACKGROUND: Doxorubicin and other anthracyclines are crucial cancer treatment drugs. However, they are associated with significant cardiotoxicity, severely affecting patient care and limiting dosage and usage. Previous studies have shown that low carbon monoxide (CO) concentrations protect against doxorubicin toxicity. However, traditional methods of CO delivery pose complex challenges for daily administration, such as dosing and toxicity. To address these challenges, we developed a novel oral liquid drug product containing CO (HBI-002) that can be easily self-administered by patients with cancer undergoing doxorubicin treatment, resulting in CO being delivered through the upper gastrointestinal tract. METHODS AND RESULTS: HBI-002 was tested in a murine model of doxorubicin cardiotoxicity in the presence and absence of lung or breast cancer. The mice received HBI-002 twice daily before doxorubicin administration and experienced increased carboxyhemoglobin levels from a baseline of ≈1% to 7%. Heart tissue from mice treated with HBI-002 had a 6.3-fold increase in CO concentrations and higher expression of the cytoprotective enzyme heme oxygenase-1 compared with placebo control. In both acute and chronic doxorubicin toxicity scenarios, HBI-002 protected the heart from cardiotoxic effects, including limiting tissue damage and cardiac dysfunction and improving survival. In addition, HBI-002 did not compromise the efficacy of doxorubicin in reducing tumor volume, but rather enhanced the sensitivity of breast 4T1 cancer cells to doxorubicin while simultaneously protecting cardiac function. CONCLUSIONS: These findings strongly support using HBI-002 as a cardioprotective agent that maintains the therapeutic benefits of doxorubicin cancer treatment while mitigating cardiac damage.

Low-Dose Colchicine Ameliorates Doxorubicin Cardiotoxicity Via Promoting Autolysosome Degradation.

BACKGROUND: The only clinically approved drug that reduces doxorubicin cardiotoxicity is dexrazoxane, but its application is limited due to the risk of secondary malignancies. So, exploring alternative effective molecules to attenuate its cardiotoxicity is crucial. Colchicine is a safe and well-tolerated drug that helps reduce the production of reactive oxygen species. High doses of colchicine have been reported to block the fusion of autophagosomes and lysosomes in cancer cells. However, the impact of colchicine on the autophagy activity within cardiomyocytes remains inadequately elucidated. Recent studies have highlighted the beneficial effects of colchicine on patients with pericarditis, postprocedural atrial fibrillation, and coronary artery disease. It remains ambiguous how colchicine regulates autophagic flux in doxorubicin-induced heart failure. METHODS AND RESULTS: Doxorubicin was administered to establish models of heart failure both in vivo and in vitro. Prior studies have reported that doxorubicin impeded the breakdown of autophagic vacuoles, resulting in damaged mitochondria and the accumulation of reactive oxygen species. Following the administration of a low dose of colchicine (0.1 mg/kg, daily), significant improvements were observed in heart function (left ventricular ejection fraction: doxorubicin group versus treatment group=43.75%±3.614% versus 57.07%±2.968%, P=0.0373). In terms of mechanism, a low dose of colchicine facilitated the degradation of autolysosomes, thereby mitigating doxorubicin-induced cardiotoxicity. CONCLUSIONS: Our research has shown that a low dose of colchicine is pivotal in restoring the autophagy activity, thereby attenuating the cardiotoxicity induced by doxorubicin. Consequently, colchicine emerges as a promising therapeutic candidate to improve doxorubicin cardiotoxicity.

Empagliflozin attenuates doxorubicin-induced cardiotoxicity by inhibiting the JNK signaling pathway.

BACKGROUND: Sodium-glucose cotransporter-2 inhibitors, such as empagliflozin, are pivotal therapies for heart failure. However, the effect of empagliflozin on doxorubicin-related cardiac dysfunction remains unclear. METHODS: Human induced pluripotent stem cell- and embryonic stem cell-derived cardiomyocytes were used to investigate the direct effect of empagliflozin on human cardiomyocytes. Then, the c-Jun amino-terminal kinases (JNK) inhibitor SP600125 was administered to the doxorubicin cardiotoxicity model in vitro and in vivo to investigate the role of JNK in empagliflozin. RESULTS: In human stem cell-derived cardiomyocytes, pretreatment with empagliflozin attenuated doxorubicin-induced cleavage of caspase 3 and other apoptosis markers. Empagliflozin significantly attenuated doxorubicin-induced phosphorylation of JNK and p38. Inhibiting the phosphorylation of JNK (SP600125) or STAT3 attenuated doxorubicin-induced apoptosis, but inhibiting the phosphorylation of p38 did not. SP600125 inhibits the phosphorylation of STAT3 (S727), and a STAT3 (Y705) inhibitor also inhibits the phosphorylation of JNK. Empagliflozin and SP600125 attenuated doxorubicin-induced increases in reactive oxygen species (ROS) and decreases in oxidized nicotinamide adenine dinucleotide (NAD+). In animal studies, empagliflozin and SP600125 attenuated doxorubicin-induced cardiac dysfunction and fibrosis. CONCLUSIONS: Empagliflozin attenuated doxorubicin-induced apoptosis by inhibiting the phosphorylation of JNK and its downstream signaling pathways, including ROS and NAD+.

Betaine ameliorates doxorubicin-induced cardiomyopathy by inhibiting oxidative stress, inflammation, and fibrosis through the modulation of AMPK/Nrf2/TGF-ß expression.

Doxorubicin (DOX) is a broad-spectrum antibiotic with potent anti-cancer activity. Nevertheless, despite having effective anti-neoplasm activity, its use has been clinically restricted due to its life-threatening side effects, such as cardiotoxicity. It is evident that betaine has anti-oxidant, and anti-inflammatory activity and has several beneficial effects, such as decreasing the amyloid-ß generation, reducing obesity, improving steatosis and fibrosis, and activating AMP-activated protein kinase (AMPK). However, whether betaine could mitigate DOX-induced cardiomyopathy is still unexplored. Cardiomyopathy was induced in male Sprague Dawley rats using DOX (4 mg/kg dose with a cumulative dose of 20 mg/kg, i.p.). Further, betaine (200 and 400 mg/kg) was co-treated with DOX through oral gavage for 28 days. After the completion of the study, several biochemical, oxidative stress parameters, histopathology, western blotting, and qRT-PCR were performed. Betaine treatment significantly reduced CK-MB, LDH, SGOT, and triglyceride levels, which are associated with cardiotoxicity. DOX-induced increased oxidative stress was also mitigated by betaine intervention as the SOD, catalase, MDA, and nitrite levels were restored. The histopathological investigation also confirmed the cardioprotective effect of betaine against DOX-induced cardiomyopathy as the tissue injury was reversed. Further, molecular analysis revealed that betaine suppressed the DOX-induced increased expression of phospho-p53, phospho-p38 MAPK, NF-kB p65, and PINK 1 with an upregulation of AMPK and downregulation of Nrf2 expression. Interestingly, qRT-PCR experiments show that betaine treatment alleviates the DOX-induced increase in inflammatory (TNF-α, NLRP3, and IL-6) and fibrosis (TGF-ß and Acta2) related gene expression, halting the cardiac injury. Interestingly, betaine also improves the mRNA expression of Nrf2, thus modulating the expression of antioxidant proteins and preventing oxidative damage. Here, we provide the first evidence that betaine treatment prevents DOX-induced cardiomyopathy by inhibiting oxidative stress, inflammation, and fibrosis by regulating AMPK/Nrf2/TGF-ß expression. We believe that betaine can be utilized as a potential novel therapeutic strategy for preventing DOX-induced cardiotoxicity.

Doxorubicin induces phosphorylation of lamin A/C and loss of nuclear membrane integrity: A novel mechanism of cardiotoxicity.

Lamin A/C, essential inner nuclear membrane proteins, have been linked to progeria, a disease of accelerated aging, and many other diseases, which include cardiac disorder. Lamin A/C mutation and its phosphorylation are associated with altering nuclear shape and size. The role of lamin A/C in regulating normal cardiac function was reported earlier. In the present study, we hypothesized that Doxorubicin (Dox) may alter total lamin A/C expression and phosphorylation, thereby taking part in cardiac injury. An in vitro cellular injury model was generated with Dox (0.1-10.0 µM) treatment on cardiomyoblast cells (H9c2) to prove our hypothesis. Increased size and irregular (ameboid) nucleus shape were observed in H9c2 cells after Dox treatment. Similarly, we have observed a significant increase in cell death on increasing the Dox concentration. The expression of lamin A/C and its phosphorylation at serine 22 significantly decreased and increased, respectively in H9c2 cells and rat hearts after Dox exposure. Phosphorylation led to depolymerization of the lamin A/C in the inner nuclear membrane and was evidenced by their presence throughout the nucleoplasm as observed by immunocytochemistry techniques. Thinning and perforation on the walls of the nuclear membrane were observed in Dox-treated H9c2 cells. LMNA-overexpression in H9c2 protected the cells from Dox-induced cell death, reversing all changes described above. Further, improvement of lamin A/C levels was observed in Dox-treated H9c2 cells when treated with Purvalanol A, a CDK1 inhibitor and N-acetylcysteine, an antioxidant. The study provides new insight regarding Dox-induced cardiac injury with the involvement of lamin A/C and alteration of inner nuclear membrane structure.

NSUN2 relies on ALYREF to regulate Nrf2-mediated oxidative stress and alleviate Dox-induced liver injury.

BACKGROUND: Doxorubicin (Dox) is associated with various liver injuries, limiting its clinical utility. This study investigates whether NSUN2 participates in Dox-induced liver injury and the associated molecular mechanism. METHODS: In vivo and in vitro liver cell injury models were constructed based on Dox therapy. The protein levels of NSUN2 and oxidative stress indicators Nrf2, HO-1, and NQO1 were evaluated by Western blot. The RNA binding potential was detected by RNA methylation immunoprecipitation (RIP). Additionally, the effect of NSUN2 on Nrf2 mRNA synthesis and localization was evaluated using an RNA fluorescence probe. RESULTS: NSUN2 was downregulated, and liver tissue suffered significant pathological damage in the Dox group. The levels of ALT and AST significantly increased. NSUN2 interference exacerbated Dox-induced liver cell damage, which was reversed by NSUN2 overexpression. RIP demonstrated that NSUN2 recognized and bound to Nrf2 mRNA. Western blot analysis showed the protein level of Nrf2 in the NSUN2-WT group was significantly higher than that of the control group, whereas there was no significant change in Nrf2 level in the mutant NSUN2 group. Luciferase analysis demonstrated that NSUN2 could recognize and activate the Nrf2 5'UTR region of LO2 cells. In addition, RIP analysis revealed that ALYREF could recognize and bind to Nrf2 mRNA and that ALYREF controls the regulatory effect of NSUN2 on Nrf2. CONCLUSION: NSUN2 regulates Dox-induced liver cell damage by increasing Nrf2 mRNA m5C methylation to inhibit inhibiting antioxidant stress. The regulatory effect of NSUN2 on Nrf2 depends on ALYREF.

Cardiomyocytes, cardiac endothelial cells and fibroblasts contribute to anthracycline-induced cardiac injury through RAS-homologous small GTPases RAC1 and CDC42.

The clinical use of the DNA damaging anticancer drug doxorubicin (DOX) is limited by irreversible cardiotoxicity, which depends on the cumulative dose. The RAS-homologous (RHO) small GTPase RAC1 contributes to DOX-induced DNA damage formation and cardiotoxicity. However, the pathophysiological relevance of other RHO GTPases than RAC1 and different cardiac cell types (i.e., cardiomyocytes, non-cardiomyocytes) for DOX-triggered cardiac damage is unclear. Employing diverse in vitro and in vivo models, we comparatively investigated the level of DOX-induced DNA damage in cardiomyocytes versus non-cardiomyocytes (endothelial cells and fibroblasts), in the presence or absence of selected RHO GTPase inhibitors. Non-cardiomyocytes exhibited the highest number of DOX-induced DNA double-strand breaks (DSB), which were efficiently repaired in vitro. By contrast, rather low levels of DSB were formed in cardiomyocytes, which however remained largely unrepaired. Moreover, DOX-induced apoptosis was detected only in non-cardiomyocytes but not in cardiomyocytes. Pharmacological inhibitors of RAC1 and CDC42 most efficiently attenuated DOX-induced DNA damage in all cell types examined in vitro. Consistently, immunohistochemical analyses revealed that the RAC1 inhibitor NSC23766 and the pan-RHO GTPase inhibitor lovastatin reduced the level of DOX-induced residual DNA damage in both cardiomyocytes and non-cardiomyocytes in vivo. Overall, we conclude that endothelial cells, fibroblasts and cardiomyocytes contribute to the pathophysiology of DOX-induced cardiotoxicity, with RAC1- and CDC42-regulated signaling pathways being especially relevant for DOX-stimulated DSB formation and DNA damage response (DDR) activation. Hence, we suggest dual targeting of RAC1/CDC42-dependent mechanisms in multiple cardiac cell types to mitigate DNA damage-dependent cardiac injury evoked by DOX-based anticancer therapy.

Ginsenoside Rb1 attenuates doxorubicin induced cardiotoxicity by suppressing autophagy and ferroptosis.

Ginsenoside Rb1 (Rb1), an active component isolated from traditional Chinese medicine Ginseng, is beneficial to many cardiovascular diseases. However, whether it can protect against doxorubicin induced cardiotoxicity (DIC) is not clear yet. In this study, we aimed to investigate the role of Rb1 in DIC. Mice were injected with a single dose of doxorubicin (20 mg/kg) to induce acute cardiotoxicity. Rb1 was given daily gavage to mice for 7 days. Changes in cardiac function, myocardium histopathology, oxidative stress, cardiomyocyte mitochondrion morphology were studied to evaluate Rb1's function on DIC. Meanwhile, RNA-seq analysis was performed to explore the potential underline molecular mechanism involved in Rb1's function on DIC. We found that Rb1 treatment can improve survival rate and body weight in Dox treated mice group. Rb1 can attenuate Dox induced cardiac dysfunction and myocardium hypertrophy and interstitial fibrosis. The oxidative stress increase and cardiomyocyte mitochondrion injury were improved by Rb1 treatment. Mechanism study found that Rb1's beneficial role in DIC is through suppressing of autophagy and ferroptosis. This study shown that Ginsenoside Rb1 can protect against DIC by regulating autophagy and ferroptosis.

Research progress on the role and mechanism of Sirtuin family in doxorubicin cardiotoxicity.

BACKGROUND: Doxorubicin (DOX) is a widely utilized anthracycline chemotherapy drug in cancer treatment, yet its efficacy is hindered by both short-term and long-term cardiotoxicity. Although oxidative stress, inflammation and mitochondrial dysfunction are established factors in DOX-induced cardiotoxicity, the precise molecular pathways remain elusive. Further exploration of the pathogenesis and identification of novel molecular targets are imperative. Recent studies have implicated the Sirtuins family in various physiological and pathological processes, suggesting their potential in ameliorating DOX-induced cardiotoxicity. Moreover, research on Sirtuins has discovered small-molecule compounds or medicinal plants with regulatory effects, representing a notable advancement in preventing and treating DOX-induced cardiac injury. PURPOSE: In this review, we delve into the pathogenesis of DOX-induced cardiotoxicity and explore the therapeutic effects of Sirtuins in mitigating this condition, along with the associated molecular mechanisms. Furthermore, we delineate the roles and mechanisms of small-molecule regulators of Sirtuins in the prevention and treatment of DOX-induced cardiotoxicity. STUDY-DESIGN/METHODS: Data for this review were sourced from various scientific databases (such as Web of Science, PubMed and Science Direct) up to March 2024. Search terms included "Sirtuins," "DOX-induced cardiotoxicity," "DOX," "Sirtuins regulators," "histone deacetylation," among others, as well as several combinations thereof. RESULTS: Members of the Sirtuins family regulate both the onset and progression of DOX-induced cardiotoxicity through anti-inflammatory, antioxidative stress and anti-apoptotic mechanisms, as well as by maintaining mitochondrial stability. Moreover, natural plant-derived active compounds such as Resveratrol (RES), curcumin, berberine, along with synthetic small-molecule compounds like EX527, modulate the expression and activity of Sirtuins. CONCLUSION: The therapeutic role of the Sirtuins family in mitigating DOX-induced cardiotoxicity represents a potential molecular target. However, further research is urgently needed to elucidate the relevant molecular mechanisms and to assess the safety and biological activity of Sirtuins regulators. This review offers an in-depth understanding of the therapeutic role of the Sirtuins family in mitigating DOX-induced cardiotoxicity, providing a preliminary basis for the clinical application of Sirtuins regulators in this condition.

Lapatinib combined with doxorubicin causes dose-dependent cardiotoxicity partially through activating the p38MAPK signaling pathway in zebrafish embryos.

Because of its enhanced antitumor efficacy, lapatinib (LAP) is commonly used clinically in combination with the anthracycline drug doxorubicin (DOX) to treat metastatic breast cancer. While it is well recognized that this combination chemotherapy can lead to an increased risk of cardiotoxicity in adult women, its potential cardiotoxicity in the fetus during pregnancy remains understudied. Here, we aimed to examine the combination of LAP chemotherapy and DOX-induced cardiotoxicity in the fetus using a zebrafish embryonic system and investigate the underlying pathologic mechanisms. First, we examined the dose-dependent cardiotoxicity of combined LAP and DOX exposure in zebrafish embryos, which mostly manifested as pericardial edema, bradycardia, cardiac function decline and reduced survival. Second, we revealed that a significant increase in oxidative stress concurrent with activated MAPK signaling, as indicated by increased protein expression of phosphorylated p38 and Jnk, was a notable pathophysiological event after combined LAP and DOX exposure. Third, we showed that inhibiting MAPK signaling by pharmacological treatment with the p38MAPK inhibitor SB203580 or genetic ablation of the map2k6 gene could significantly alleviate combined LAP and DOX exposure-induced cardiotoxicity. Thus, we provided both pharmacologic and genetic evidence to suggest that inhibiting MAPK signaling could exert cardioprotective effects. These findings have implications for understanding the potential cardiotoxicity induced by LAP and DOX combinational chemotherapy in the fetus during pregnancy, which could be leveraged for the development of new therapeutic strategies.