Cancer therapy-induced cardiovascular toxicity: old/new problems and old drugs

Cancer mortality risk from short-term PM2.5 exposure and temporal variations in Brazil

Although some studies have found that short-term PM2.5 exposure is associated with lung cancer deaths, its impact on other cancer sites is unclear. To answer this research question, this time-stratified case-crossover study used individual cancer death data between January 1, 2000, and December 31, 2019, extracted from the Brazilian mortality information system to quantify the associations between short-term PM2.5 exposure and cancer mortality from 25 common cancer sites. Daily PM2.5 concentration was aggregated at the municipality level as the key exposure. The study included a total of 34,516,120 individual death records, with the national daily mean PM2.5 exposure 15.3 (SD 4.3) μg/m3. For every 10-μg/m3 increase in three-day average PM2.5 exposure, the odds ratio (OR) for all-cancer mortality was 1.04 (95% CI 1.03-1.04). Apart from all-cancer deaths, PM2.5 exposure may impact cancers of oesophagus (1.04, 1.00-1.08), stomach (1.05, 1.02-1.08), colon-rectum (1.04, 1.01-1.06), lung (1.04, 1.02-1.06), breast (1.03, 1.00-1.06), prostate (1.07, 1.04-1.10), and leukaemia (1.05, 1.01-1.09). During the study period, acute PM2.5 exposure contributed to an estimated 1,917,994 cancer deaths, ranging from 0 to 6,054 cases in each municipality. Though there has been a consistent downward trend in PM2.5-related all-cancer mortality risks from 2000 to 2019, the impact remains significant, indicating the continued importance of cancer patients avoiding PM2.5 exposure. This nationwide study revealed a notable association between acute PM2.5 exposure and heightened overall and site-specific cancer mortality for the first time to our best knowledge. The findings suggest the importance of considering strategies to minimize such exposure in cancer care guidelines. ENVIRONMENTAL IMPLICATION: The 20-year analysis of nationwide death records in Brazil revealed that heightened short-term exposure to PM2.5 is associated with increased cancer mortality at various sites, although this association has gradually decreased over time. Despite the declining impact, the research highlights the persistent adverse effects of PM2.5 on cancer mortality, emphasizing the importance of continued research and preventive measures to address the ongoing public health challenges posed by air pollution.

Therapy-naïve malignancy causes cardiovascular disease: a state-of-the-art cardio-oncology perspective

Cardiovascular disease (CVD) and cancer are the leading causes of mortality worldwide. Although generally thought of as distinct diseases, the intersectional overlap between CVD and cancer is increasingly evident in both causal and mechanistic relationships. The field of cardio-oncology is largely focused on the cardiotoxic effects of cancer therapies (e.g., chemotherapy, radiation). Furthermore, the cumulative effects of cardiotoxic therapy exposure and the prevalence of CVD risk factors in patients with cancer lead to long-term morbidity and poor quality of life in this patient population, even when patients are cancer-free. Evidence from patients with cancer and animal models demonstrates that the presence of malignancy itself, independent of cardiotoxic therapy exposure or CVD risk factors, negatively impacts cardiac structure and function. As such, the primary focus of this review is the cardiac pathophysiological and molecular features of therapy-naïve cancer. We also summarize the strengths and limitations of preclinical cancer models for cardio-oncology research and discuss therapeutic strategies that have been tested experimentally for the treatment of cancer-induced cardiac atrophy and dysfunction. Finally, we explore an adjacent area of interest, called "reverse cardio-oncology," where the sequelae of heart failure augment cancer progression. Here, we emphasize the cross-disease communication between malignancy and the injured heart and discuss the importance of chronic low-grade inflammation and endocrine factors in the progression of both diseases.

Anthracycline cardiotoxicity is exacerbated by global p38β genetic ablation in a sexually dimorphic manner but unaltered by cardiomyocyte-specific p38α loss

Severe cardiotoxic effects limit the efficacy of doxorubicin (DOX) as a chemotherapeutic agent. Activation of intracellular stress signaling networks, including p38 mitogen-activated protein kinase (MAPK), has been implicated in DOX-induced cardiotoxicity (DIC). However, the roles of the individual p38 isoforms in DIC remain incompletely elucidated. We recently reported that global p38δ deletion protected female but not male mice from DIC, whereas global p38γ deletion did not significantly modulate it. Here we studied the in vivo roles of p38α and p38β in acute DIC. Male and female mice with cardiomyocyte-specific deletion of p38α or global deletion of p38β and their wild-type counterparts were injected with DOX. Survival and health were tracked for 10 days postinjection. Cardiac function was assessed by echocardiography and electrocardiography and fibrosis by Picrosirius red staining. Expression and activation of signaling proteins and inflammatory markers were measured by Western blot, phosphorylation array, and chemokine/cytokine array. Global p38β deletion significantly aggravated DIC and worsened cardiac electrical and mechanical function deterioration in female mice. Mechanistically, DIC in p38β-null female mice correlated with increased autophagy, sustained hyperactivation of proapoptotic JNK signaling, as well as remodeling of a myocardial inflammatory environment. In contrast, cardiomyocyte-specific deletion of p38α improved survival of DOX30-treated male mice 5 days posttreatment but did not influence cardiac function in DOX-treated male or female mice. Our data highlight the sex- and isoform-specific roles of p38α and p38β MAPKs in DOX-induced cardiac injury and suggest a novel in vivo function of p38β in protecting female mice from DIC.NEW & NOTEWORTHY We show that p38α and p38β have distinct in vivo functions in a murine model of acute DIC. Specifically, although conditional cardiomyocyte-specific p38α deletion exhibited mild cardioprotective effects in male mice, p38β deletion exacerbated the DOX cardiotoxicity in female mice. Our findings caution against employing pyridinyl imidazole inhibitors that target both p38α and p38β isoforms as a cardioprotective strategy against DIC. Such an approach could have undesirable sex-dependent effects, including attenuating p38β-dependent cardioprotection in females.

Immune interactions in pembrolizumab (PD-1 inhibitor) cancer therapy and cardiovascular complications

The use of immunotherapies like pembrolizumab (PEM) is increasingly common for the management of numerous cancer types. The use of PEM to bolster T-cell response against tumor growth is well documented. However, the interactions PEM has on other immune cells to facilitate tumor regression and clearance is unknown and warrants further investigation. In this review, we present literature findings that have reported the interactions of PEM in stimulating innate and adaptive immune cells, which enhance cytotoxic phenotypes. This triggers secretion of cytokines and chemokines, which have both beneficial and detrimental effects. We also describe how this leads to the development of rare but underreported occurrence of PEM-induced immune-related cardiovascular complications that arise suddenly and progress rapidly to debilitating and fatal consequences. This review encourages further research and investigation of PEM-induced cardiovascular complications and other immune cell interactions in patients with cancer. As PEM therapy in treating cancer types is expanding, we expect that this review will inform health care professionals of diverse specializations of medicine like dermatology (melanoma skin cancers), ophthalmology (eye cancers), and pathology (hematological malignancies) about PEM-induced cardiac complications.

Left Atrial Appendage Closure Outcomes in Patients With Cancer at a Single Tertiary Center

Atrial fibrillation is the most common arrhythmia in patients with underlying malignancy. Patients with cancer have a higher risk of bleeding, and at the same time, carry an elevated risk of thromboembolism related to the hypercoagulable state, type of cancer, and anticancer treatment, rendering safe anticoagulation challenging in this population. Left atrial appendage closure is an alternative treatment option in patients with atrial fibrillation and high bleeding risk; however, the data on patients with cancer are limited. Our study aimed to compare the long-term outcomes in patients with cancer receiving left atrial appendage closure using the WATCHMAN device. This is a prospective, single-center study comparing outcomes in 389 patients who underwent percutaneous left atrial appendage closure using the WATCHMAN device over 5 years in a single, large academic hospital in the United States. The postprocedural outcomes of mortality, stroke, and major bleeding were evaluated in patients with and without cancer. Our study included 57 patients with cancer and 332 without cancer. The baseline characteristics were similar between the 2 groups. Metastatic disease was present in 16.4% of patients, and 25% were receiving active treatment at the time of the procedure. The median follow-up time was 354 (interquartile range 85 to 790) days. There was no difference in mortality (hazard ratio [HR] 1.3, 95% confidence interval [CI] 0.72 to 2.35, p = 0.38), major bleeding episodes (HR 1.2, 95% CI 0.45 to 3.33, p = 0.68), and stroke (HR 0.64, 95% CI 0.19 to 2.21, p = 0.49) at 3 years after the procedure in patients with and without cancer. There was no difference in the composite outcome (postprocedural mortality, stroke, and major bleeding) between the 2 groups (HR 1.25, CI 0.75 to 2.07, p = 0.38). Percutaneous left atrial appendage closure in patients with cancer appears to be safe and has a similar long-term risk compared with patients without cancer.

Combination Therapy of Radiation and Hyperthermia, Focusing on the Synergistic Anti-Cancer Effects and Research Trends

Despite significant therapeutic advances, the toxicity of conventional therapies remains a major obstacle to their application. Radiation therapy (RT) is an important component of cancer treatment. Therapeutic hyperthermia (HT) can be defined as the local heating of a tumor to 40-44 °C. Both RT and HT have the advantage of being able to induce and regulate oxidative stress. Here, we discuss the effects and mechanisms of RT and HT based on experimental research investigations and summarize the results by separating them into three phases. Phase (1): RT + HT is effective and does not provide clear mechanisms; phase (2): RT + HT induces apoptosis via oxygenation, DNA damage, and cell cycle arrest; phase (3): RT + HT improves immunological responses and activates immune cells. Overall, RT + HT is an effective cancer modality complementary to conventional therapy and stimulates the immune response, which has the potential to improve cancer treatments, including immunotherapy, in the future.

Analysis of the Relationship between Scleritis and T Cell Activation in Patients with Hepatocellular Carcinoma Treated with PD-1 Carrelizumab

In order to explore the function of inhibiting the immune effect, the relationship between programmed death receptor 1 (PD-1) carrelizumab in the treatment of hepatocellular carcinoma-induced scleritis and T cell activation is investigated. A total of 120 patients with primary liver cancer treated in the department of oncology of our hospital from July 2020 to January 2022 are selected and treated with carrelizumab. According to the occurrence of PD-1 carrelizumab treatment, the patients are divided into the scleritis group and nonscleritis group. The levels of T cells, PD-1, PD-L1 proteins, and serum inflammatory factors at different time points are compared. The experimental results show that the occurrence of scleritis after liver cancer treatment with PD-1 carrelizumab is closely associated with Treg cells, the percentage of Th17 cells, the expression of PD-1, PD-L1 proteins, and inflammatory factors. It is clearly evident that PD-1 carrelizumab can increase the risk of scleritis by affecting T cell activation.

Inhibition of TNF-α and JNK Signaling Pathway Can Reduce Paclitaxel-Induced Apoptosis of Mouse Cardiomyocytes

Paclitaxel (PTX) is a widely used chemotherapeutic drug for treating tumors. However, studies have shown that it can cause cardiac problems such as arrhythmia, myocarditis, chronic cardiomyopathy, and heart failure. Therefore, it is essential to study the mechanism behind the cardiotoxicity of PTX in tumor treatment. In this study, we initially injected PTX into mice to establish a myocardial cell apoptosis model to observe the degree of damage to mouse myocardium caused by PTX. Upon determining the levels of mouse myocardial creatine phosphokinase (CK), myokinase isoenzyme (CK-MB), aspartate transaminase (AST), and lactate dehydrogenase (LDH), we found that all of these levels showed apparent increases in mice treated with PTX. Further analyses of the TNF-α level and the expression of Jun N-terminal kinase (JNK) and Bcl-2 family-related proteins in myocardial tissue were performed. It was found that PTX increased the protein levels of TNF-α, Bax, p-JNK, and JNK in myocardial tissue but decreased the protein level of Bcl-2. After 1 month of PTX treatment in mice, we inhibited the expression of TNF-α and JNK proteins, which reduced the effect of paclitaxel on the apoptosis of mouse cardiomyocytes. The protein levels of Bax, p-JNK, and TNF-α in cardiomyocytes were reduced, while there was a relative increase in the Bcl-2 protein level. The findings suggested that inhibition of the NK signaling pathway and TNF-α can lessen the effect of PTX on mouse cardiomyocytes.

Risk factors associated with cardiovascular mortality among gastric cancer patients: a population-based analysis

BACKGROUND

Cancer patients were found at a high risk of death from cardiovascular disease. This study aims to assess cardiovascular mortality risk and identify the potential risk factors associated with cardiovascular mortality among gastric cancer patients.

METHODS

Gastric cancer patients were collected from the Surveillance Epidemiology and End Results database during 1975-2016. Standardized mortality ratios were calculated to compare cardiovascular mortality rates between gastric cancer patients and the general US population. Univariable Cox analysis and multivariable stepwise Cox analysis were adopted to identify the potential risk factors for cardiovascular disease death after gastric cancer diagnosis.

RESULTS

There were 10 886 cardiovascular disease deaths identified among 165 433 individuals with gastric cancer observed for 410207.20 person-years. Gastric cancer patients were at a higher cardiovascular disease mortality risk (standardized mortality ratio = 3.35, 95% confidence interval: 3.24-3.47, P < 0.05). The study showed that older age at diagnosis (>80 years vs. 0-69 years, hazard ratio = 7.05, 95% confidence interval: 6.66-7.46, P < 0.001; 70-80 years vs. 0-69 years, hazard ratio = 3.35, 95% confidence interval: 3.19-3.53, P < 0.001), male sex (vs. female, hazard ratio = 1.39, 95% confidence interval: 1.33-1.45, P < 0.001), black race (vs. white, hazard ratio = 1.31, 95% confidence interval: 1.24-1.38, P < 0.001), without a partner (divorced/separated vs. married/partnered, hazard ratio = 1.35, 95% confidence interval: 1.25-1.45, P < 0.001; single vs. married/partnered, hazard ratio = 1.20, 95% confidence interval: 1.12-1.29, P < 0.001; widowed vs. married/partnered, hazard ratio = 1.41, 95% confidence interval: 1.34-1.48, P < 0.001), living in the northern plains (vs. pacific coast, hazard ratio = 1.23, 95% confidence interval: 1.16-1.29, P < 0.001) and surgery not performed (vs. performed, hazard ratio = 1.70, 95% confidence interval: 1.61-1.79, P < 0.001) were significantly associated with increased risk of cardiovascular disease death. Compared with patients with localized stage, distant staged patients were less likely to die of cardiovascular disease (hazard ratio = 0.88, 95% confidence interval: 0.83-0.94, P < 0.001).

CONCLUSIONS

Gastric cancer patients were at an increased risk of cardiovascular disease death. Older age at diagnosis, male sex, black race, without a partner, living in the northern plains and surgery not performed were significantly associated with cardiovascular disease death after gastric cancer diagnosis.

Pan-cancer analysis identifies BIRC5 as a prognostic biomarker

Background

The BIRC5 gene encodes for the Survivin protein, which is a member of the inhibitor of apoptosis family. Survivin is found in humans during fetal development, but generally not in adult cells thereafter. Previous studies have shown that Survivin is abundant in most cancer cells, thereby making it a promising target for anti-cancer drugs and a potential prognostic tool.

Methods

To assess genetic alterations and mutations in the BIRC5 gene as well as BIRC5 co-expression with other genes, genomic and transcriptomic data were downloaded via cBioPortal for approximately 9000 samples from The Cancer Genome Atlas (TCGA) representing 33 different cancer types and 11 pan-cancer organ systems, and validated using the ICGC Data Portal and COSMIC. TCGA BIRC5 RNA sequencing data from 33 different cancer types and matching normal tissue samples for 16 cancer types were downloaded from Broad GDAC Firehose and validated using breast cancer microarray data from our previous work and data sets from the GENT2 web-based tool. Survival data were analyzed with multivariable Cox proportional hazards regression analysis and validated using KM plotter for breast-, ovarian-, lung- and gastric cancer.

Results

Although genetic alterations in BIRC5 were not common in cancer, BIRC5 expression was significantly higher in cancer tissue compared to normal tissue in the 16 different cancer types. For 14/33 cancer types, higher BIRC5 expression was linked to worse overall survival (OS, 4/14 after adjusting for both age and tumor grade and 10/14 after adjusting only for age). Interestingly, higher BIRC5 expression was associated with better OS in lung squamous cell carcinoma and ovarian serous cystadenocarcinoma. Higher BIRC5 expression was also linked to shorter progressive-free interval (PFI) for 14/33 cancer types (4/14 after adjusting for both age and tumor grade and 10/14 after adjusting only for age). External validation showed that high BIRC5 expression was significantly associated with worse OS for breast-, lung-, and gastric cancer.

Conclusions

Our findings suggest that BIRC5 overexpression is associated with the initiation and progression of several cancer types, and thereby a promising prognostic biomarker.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09371-0.

Coronary Artery Disease and Cancer: Treatment and Prognosis Regarding Gender Differences

Simple Summary

Cardiovascular disease and cancer are the leading causes of hospitalization and mortality in high-income countries. Studies of myocardial infarction show a disadvantage for the female sex in terms of survival and development of heart failure after myocardial infarction. The extent to which this also applies to the co-occurrence of coronary heart disease and cancer was investigated and analyzed here in large registry studies. Particular attention has been paid to the four most common cancers and hematologic diseases associated with coronary artery disease requiring treatment.

Abstract

Cardiovascular disease and cancer remain the leading causes of hospitalization and mortality in high-income countries. Survival after myocardial infarction has improved but there is still a difference in clinical outcome, mortality, and developing heart failure to the disadvantage of women with myocardial infarction. Most major cardiology trials and registries have excluded patients with cancer. As a result, there is only very limited information on the effects of coronary artery disease in cancer patients. In particular, the outcomes in women with cancer and coronary artery disease and its management remain empiric. We reviewed studies of over 27 million patients with coronary artery disease and cancer. Our review focused on the most important types of cancer (breast, colon, lung, prostate) and hematological malignancies with particular attention to sex-specific differences in treatment and prognosis.

Risk of cardiovascular toxicities and hypertension in nonmetastatic castration-resistant prostate cancer patients treated with novel hormonal agents: a systematic review and meta-analysis

Background: With hormonal agents quickly expanding as novel therapeutic options in nonmetastatic castration-resistant prostate cancer (nmCRPC), the toxicity profile of enzalutamide, apalutamide, and darolutamide should be kept in mind.Methods: We performed an updated meta-analysis with the aim to analyze the risk of treatment-related cardiovascular (CV) events, any grade, and grade 3-4 (G3-4) hypertension in nmCRPC patients treated with enzalutamide, apalutamide, and darolutamide plus androgen deprivation therapy (ADT) versus ADT plus placebo in randomized controlled trials (RCTs). Results were compared by calculating Relative Risk (RR) with 95% confidence intervals (CIs); RRs were combined with Mantel-Haenszel method.Results: Three RCTs involving 4110 patients were available for the meta-analysis. According to our results, the addition of novel hormonal agents was associated with a significantly increased risk of CV events (RR = 1.71; 95% CI 1.29-2.27) and G3-4 hypertension (RR = 1.53; 95% CI 1.19-1.97). In addition, a trend toward a higher risk of any grade hypertension was reported in the experimental arm.Conclusions: The use of enzalutamide, apalutamide, and darolutamide in nmCRPC patients implies a careful benefit-risk assessment. Real-world, large-cohort studies are warranted to confirm the findings of our meta-analysis.

Comparative Evaluation of Engineered Polypeptide Scaffolds in HER2-Targeting Magnetic Nanocarrier Delivery

Targeted drug delivery is one of the most intriguing and challenging issues in modern biomedicine. For active targeting, full-size IgG molecules (150 kDa) are usually used. Recent studies have revealed that small artificial polypeptide scaffolds such as DARPins (14 kDa) and affibodies (8 kDa) are much more promising tools for drug delivery due to their small size, artificial nature, low immunogenicity, and many other properties. However, there is no comparative information on the targeting abilities of scaffold polypeptides, which should be taken into account when developing drug delivery systems (DDSs). The present work is the first comprehensive study on the comparison of the effectiveness of different HER2-targeting proteins within the architecture of nanoparticles. Namely, we synthesized trimodal nanoparticles: magnetic, fluorescent, and directed toward HER2 oncomarker on cancer cells. The magnetic particles (MPs) were covalently modified with (i) full-size IgG, 150 kDa, (ii) DARPin_G3, 14 kDa, and (iii) affibody Z_HER2:342, 8 kDa. We showed that the number of DARPin_G3 and affibody Z_HER2:342 molecules conjugated to the nanoparticle surface are 10 and 40 times higher, respectively, than the corresponding value for trastuzumab. Using the methods of magnetic particle quantification (MPQ)-cytometry and confocal microscopy, we showed that all types of the obtained magnetic conjugates specifically labeled HER2-overexpressing cells. Namely, we demonstrated that particle binding to HER2-positive cells is 1113 ± 39 fg/cell for MP*trastuzumab, 1431 ± 186 fg/cell for MP*Z_HER2:342, and 625±21 fg/cell for MP*DARPin_G3, which are 2.77, 2.75, and 2.30 times higher than the corresponding values for control HER2-negative cells. Thus, we showed that the smallest HER2-recognizing polypeptide affibody Z_HER2:342 is more effective in terms of specificity and selectivity in nanoparticle-mediated cell labeling.

Intra- and intercellular signaling pathways associated with drug-induced cardiac pathophysiology

Cardiac physiology and homeostasis are maintained by the interaction of multiple cell types, via both intra- and intercellular signaling pathways. Perturbations in these signaling pathways induced by oncology therapies can reduce cardiac function, ultimately leading to heart failure. As cancer survival increases, related cardiovascular complications are becoming increasingly prevalent, thus identifying the perturbations and cell signaling drivers of cardiotoxicity is increasingly important. Here, we discuss the homotypic and heterotypic cellular interactions that form the basis of intra- and intercellular cardiac signaling pathways, and how oncological agents disrupt these pathways, leading to heart failure. We also highlight the emerging systems biology techniques that can be applied, enabling a deeper understanding of the intra- and intercellular signaling pathways across multiple cell types associated with cardiovascular toxicity.

Predicting and Quantifying Antagonistic Effects of Natural Compounds Given with Chemotherapeutic Agents: Applications for High-Throughput Screening

Natural products have been used for centuries to treat various human ailments. In recent decades, multi-drug combinations that utilize natural products to synergistically enhance the therapeutic effects of cancer drugs have been identified and have shown success in improving treatment outcomes. While drug synergy research is a burgeoning field, there are disagreements on the definitions and mathematical parameters that prevent the standardization and proper usage of the terms synergy, antagonism, and additivity. This contributes to the relatively small amount of data on the antagonistic effects of natural products on cancer drugs that can diminish their therapeutic efficacy and prevent cancer regression. The ability of natural products to potentially degrade or reverse the molecular activity of cancer therapeutics represents an important but highly under-emphasized area of research that is often overlooked in both pre-clinical and clinical studies. This review aims to evaluate the body of work surrounding the antagonistic interactions between natural products and cancer therapeutics and highlight applications for high-throughput screening (HTS) and deep learning techniques for the identification of natural products that antagonize cancer drug efficacy.

TILRR (FREM1 isoform 2) is a prognostic biomarker correlated with immune infiltration in breast cancer

In atherosclerosis, upregulated TILRR (FREM1 isoform 2) expression increases immune cell infiltration. We hypothesized that TILRR expression is also correlated with cancer progression. By analyzing data from Oncomine and the Tumor Immune Estimation Resource, we found that TILRR mRNA expression was significantly lower in breast cancer tissue than adjacent normal tissue. Kaplan-Meier survival analysis and immunohistochemical staining revealed shortened overall survival and disease-free survival in patients with low TILRR expression. TILRR transcript expression was positively correlated with immune score, immune cell biomarkers and the expression of CXCL10 and CXCL11. TILRR expression was also positively correlated with CD8+ and CD4+ T-cell infiltration. These correlations were verified using the ESTIMATE algorithm, gene set enrichment analysis and Q-PCR. We concluded that impaired TILRR expression is correlated with breast cancer prognosis and immune cell infiltration.

Inhibition of miR-25 attenuates doxorubicin-induced apoptosis, reactive oxygen species production and DNA damage by targeting PTEN

Background: Doxorubicin (DOX) is one of the widely used anti-cancer drugs, whereas it can induce irreversible cardiac injury in a dose-dependent manner which limits its utility in clinic. Our study aimed to investigate the relationship between miR-25 and DOX-induced cardiac injury and its underlying mechanism. Methods: Mice and H9c2 cells were exposed to DOX. The overexpressed or knockdown of miR-25 in H9c2 cells was achieved by miR-25 mimic or inhibitor and the efficiency of transfection was identified by qRT-PCR or Western blotting. Cell viability, apoptotic cell rate, and levels of apoptosis-related proteins were determined by CCK-8, flow cytometry, and Western blotting, respectively. Furthermore, Western blotting and immunofluorescence staining (IF) were performed to assess the expression levels of reactive oxygen species and degree of DNA damage. Results: As a result, DOX significantly upregulated miR-25 expression in mice and H9c2 cells and reduced cell viability and increased cell apoptosis in vitro and in vivo. miR-25 overexpression expedited cell injury induced by DOX in H9c2 cells demonstrated by the increased cell apoptosis and reactive oxygen species (ROS) production, whereas miR-25 inhibition attenuated the cell injury. Furthermore, miR-25 negatively controlled the expression of phosphatase and tensin homolog deleted on chromosome 10 (PTEN). Intervention the expression of PTEN using si-PTEN reversed the beneficial effects of miR-25 inhibition on DOX-injured H9c2 cells. Conclusion: In conclusion, this study demonstrated that miR-25 is involved in DOX-induced cell damage through the regulation of PTEN expression.