Apigenin Attenuates Adriamycin-Induced Cardiomyocyte Apoptosis via the PI3K/AKT/mTOR Pathway

Unrevealing the mechanisms behind the cardioprotective effect of wheat polyphenolics

Cardiovascular diseases pose a major threat to both life expectancy and quality of life worldwide, and a concerning level of disease burden has been attained, particularly in middle- and low-income nations. Several drugs presently in use lead to multiple adverse events. Thus, it is urgently needed to develop safe, affordable, and effective management of cardiovascular diseases. Emerging evidence reveals a positive association between polyphenol consumption and cardioprotection. Whole wheat grain and allied products are good sources of polyphenolic compounds bearing enormous cardioprotective potential. Polyphenolic extract of the entire wheat grain contains different phenolic compounds viz. ferulic acid, caffeic acid, chlorogenic acid, p-coumaric acid, sinapic acid, syringic acid, vanillic acid, apigenin, quercetin, luteolin, etc. which exert cardioprotection by reducing oxidative stress and interfering with different toxicological processes. The antioxidant capacity has been thought to exert the cardioprotective mechanism of wheat grain polyphenolics, which predominantly suppresses oxidative stress, inflammation and fibrosis by downregulating several pathogenic signaling events. However, the combined effect of polyphenolics appears to be more prominent than that of a single molecule, which might be attained due to the synergy resulting in multimodal cardioprotective benefits from multiple phenolics. The current article covers the bioaccessibility and possible effects of wheat-derived polyphenolics in protecting against several cardiovascular disorders. This review discusses the mechanistic pharmacology of individual wheat polyphenols on the cardiovascular system. It also highlights the comparative superiority of polyphenolic extracts over a single phenolic.

The Role of mTOR in the Doxorubicin-Induced Cardiotoxicity: A Systematic Review

Doxorubicin (DOX) is a chemotherapy drug known to induce metabolic changes in the heart, leading to potential heart toxicity. These changes impact various cellular functions and pathways such as disrupting the mechanistic target of rapamycin (mTOR) signaling pathway. The study aimed to investigate the effect of DOX on the mTOR pathway through an in vivo systematic review. Databases were searched on September 11, 2023. We finally included 30 in vivo studies that examined the mTOR expression in cardiac tissue samples. The present study has shown that the PI3K/AKT/mTOR, the AMPK/mTOR, the p53/mTOR signaling, the mTOR/TFEB pathway, the p38 MAPK/mTOR, the sestrins/mTOR, and the KLF15/eNOS/mTORC1 signaling pathways play a crucial role in the development of DOX-induced cardiotoxicity. Inhibition or dysregulation of these pathways can lead to increased oxidative stress, apoptosis, and other adverse effects on the heart. Strategies that target and modulate the mTOR pathways, such as the use of mTOR inhibitors like rapamycin, have the potential to enhance the anticancer effects of DOX while also mitigating its cardiotoxic side effects.

The Protective Effect of Flavonoids in the Diet on Autophagy-Related Cardiac Impairment

The compounds known as flavonoids, commonly found in fruits, vegetables, legumes, medicinal herbs, chocolate, and coffee and tea beverages, have been extensively researched for their impact on cardiovascular health. Flavonoids, with their demonstrated potential, have shown promising effects in regulating blood vessel function and apoptotic processes, as well as in improving lipid profiles. While their powerful antioxidant properties were initially thought to be the main reason behind these effects, recent studies have uncovered new insights into the positive effects of flavonoids on cardiovascular health, and researchers have now identified several signaling pathways and mechanisms that also play a role. Of particular interest are the studies that have highlighted the role of autophagy in maintaining the physiological functions of cardiomyocytes and protecting them from harm. Recent publications have linked the dysregulation of autophagic processes with the development of cardiomyopathies, heart failure, and other cardiovascular diseases. This review aims to present the latest, novel findings from preclinical research regarding the potential beneficial effects of flavonoids on various heart conditions associated with altered autophagy processes.

Role of Oxidative Stress and Inflammation in Doxorubicin-Induced Cardiotoxicity: A Brief Account

Cardiotoxicity is the main side effect of several chemotherapeutic drugs. Doxorubicin (Doxo) is one of the most used anthracyclines in the treatment of many tumors, but the development of acute and chronic cardiotoxicity limits its clinical usefulness. Different studies focused only on the effects of long-term Doxo administration, but recent data show that cardiomyocyte damage is an early event induced by Doxo after a single administration that can be followed by progressive functional decline, leading to overt heart failure. The knowledge of molecular mechanisms involved in the early stage of Doxo-induced cardiotoxicity is of paramount importance to treating and/or preventing it. This review aims to illustrate several mechanisms thought to underlie Doxo-induced cardiotoxicity, such as oxidative and nitrosative stress, inflammation, and mitochondrial dysfunction. Moreover, here we report data from both in vitro and in vivo studies indicating new therapeutic strategies to prevent Doxo-induced cardiotoxicity.

Analysis of phytochemical components of Tibetan medicine Pedicularis flava and Pedicularis muscicola by GC-MS and UHPLC-TOF-MS

Traditional medicine, 'LuRu', is a commonly used Tibetan medicine for clearing away heat and detoxifying. Dried products of Pedicularis flava and Pedicularis muscicola are often used as 'LuRu' in the market. This study aims to compare the chemical constituents of P. flava and P. muscicola using GC-MS and UPLC-TOF-MS, and confirm which plant species is more suitable to be used as 'LuRu'. A total of 46 and 68 compounds were identified from the volatile and non-volatile components, respectively. Out of these, 17 and 37 volatile and non-volatile components, respectively, had pharmacological activities. P. flava showed a higher content of the same active components than P. muscicola. Good biological activities are only observed in the unique components in P. flava, and not in P. muscicola. The two herbs should not be mixed in clinical medication. Our study shows that P. flava is better suited as a high-quality herb for the Tibetan medicine, 'LuRu'.

Puerarin inhibits NHE1 activity by interfering with the p38 pathway and attenuates mitochondrial damage induced by myocardial calcium overload in heart failure rats

Previous studies have shown that puerarin plays a key role in protecting humans and animals from cardiovascular diseases. The exact mechanism of the therapeutic effect of puerarin on various cardiovascular diseases (protective effect on cardiomyocytes) is still unclear. In the present study, we identify the role of puerarin in an animal model of experimental heart failure (HF) and explore its underlying mechanisms. The HF rat model is induced by intraperitoneal injection of adriamycin (ADR), and puerarin is administered intragastrically at low, medium, and high concentrations. We demonstrate that puerarin significantly improves myocardial fibrosis and inflammatory infiltration and, as a result, improves cardiac function in ADR-induced HF rats. Mechanistically, we find for the first time that puerarin inhibits overactivated Na +/H + exchange isoform 1 (NHE1) in HF, which may improve HF by decreasing Na + and Ca 2+ ion concentrations and attenuating mitochondrial damage caused by calcium overload; on the other hand, puerarin inhibits the activation of the p38 pathway in HF, reduces the expressions of TGF-β and proinflammatory cytokines, and suppresses myocardial fibrosis. In conclusion, our results suggest that Puerarin is an effective drug against HF and may play a protective role in the myocardium by inhibiting the activation of p38 and its downstream NHE1.

The Role of mTOR in Doxorubicin-Altered Cardiac Metabolism: A Promising Therapeutic Target of Natural Compounds

Doxorubicin (DOX) is commonly used for the treatment of various types of cancer, however can cause serious side effects, including cardiotoxicity. The mechanisms involved in DOX-induced cardiac damage are complex and not yet fully understood. One mechanism is the disruption of cardiac metabolism, which can impair cardiac function. The mammalian target of rapamycin (mTOR) is a key regulator of cardiac energy metabolism, and dysregulation of mTOR signaling has been implicated in DOX-induced cardiac dysfunction. Natural compounds (NCs) have been shown to improve cardiac function in vivo and in vitro models of DOX-induced cardiotoxicity. This review article explores the protective effects of NCs against DOX-induced cardiac injury, with a focus on their regulation of mTOR signaling pathways. Generally, the modulation of mTOR signaling by NCs represents a promising strategy for decreasing the cardiotoxic effects of DOX.

Resources for Human Health from the Plant Kingdom: The Potential Role of the Flavonoid Apigenin in Cancer Counteraction

Apigenin is one of the most widespread flavonoids in the plant kingdom. For centuries, apigenin-containing plant preparations have been used in traditional medicines to treat diseases that have an inflammatory and/or degenerative component. In the 1980s, apigenin was proposed to interfere with the process of carcinogenesis. Since then, more and more evidence has demonstrated its anticancer efficacy, both in vitro and in vivo. Apigenin has been shown to target signaling pathways involved in the development and progression of cancer, such as PI3K/Akt/mTOR, MAPK/ERK, JAK/STAT, NF-κB, and Wnt/β-catenin pathways, and to modulate different hallmarks of cancer, such as cell proliferation, metastasis, apoptosis, invasion, and cell migration. Furthermore, apigenin modulates PD1/PD-L1 expression in cancer/T killer cells and regulates the percentage of T killer and T regulatory cells. Recently, apigenin has been studied for its synergic and additive effects when combined with chemotherapy, minimizing the side effects. Unfortunately, its low bioavailability and high permeability limit its therapeutic applications. Based on micro- and nanoformulations that enhance the physical stability and drug-loading capacity of apigenin and increase the bioavailability of apigenin, novel drug-delivery systems have been investigated to improve its solubility.

Mitochonic acid 5 rescues cardiomyocytes from doxorubicin-induced toxicity via repressing the TNF-α/NF-κB/NLRP3-mediated pyroptosis

AIMS

Doxorubicin (DOX) is an effective anti-tumor drug, but the cardiotoxicity severely limits its clinical use. Interestingly, a hypothesis has emerged suggesting an association between DOX-induced cardiotoxicity and mitochondrial disorders and oxidative stress. The mitochonic acid 5 (MA5) shows promise in alleviating mitochondrial dysfunction by promoting mitochondrial ATP synthesis and reducing reactive oxygen species (ROS) accumulation, though its potential in ameliorating DOX-induced cardiotoxicity remains elusive.

METHODS

Network pharmacology approach, molecular docking techniques, and molecular dynamics simulation (MDS) were used to reveal the specific drug targets and pharmaceutical mechanisms involved in the treatment of DOX-induced cardiotoxicity using MA5. For experimental verification, cardiomyocytes (H9c2) and mice were exposed to DOX in the presence or absence of MA5. Our investigation involved the assessment of echocardiographic parameters, cardiac enzymes, inflammatory factors, mitochondrial function, myocardial structure, and cardiomyocyte pyroptosis.

RESULTS

Among the 100 core targets identified in network pharmacology, MA5 was pharmacologically active against DOX-induced cardiotoxicity via pathways implicated in cancer, prostate cancer, lipids and atherosclerosis. Molecular docking analysis confirmed that MA5 docked well with TNF-α, interleukin-6 (IL-6), and caspase-3. Furthermore, MA5 exhibited a stronger affinity toward TNF-α than IL-6 and caspase-3. Subsequent MDS revealed the stability of binding between MA5 and TNF-α. The DOX-challenged mice also displayed abnormal myocardial enzymogram, disrupted systolic and diastolic function, and elevated inflammation and cardiomyocyte pyroptosis, which could be mitigated by the administration of MA5. Similarly, H9c2 cells exposed to DOX showed increased intracellular ROS production and impaired mitochondrial function, which were relieved by MA5 treatment.

CONCLUSION

Our findings suggest that MA5 attenuates DOX-induced cardiac anomalies through the TNF-α-mediated regulation of inflammation and pyroptosis. These insights offer a potential therapeutic strategy for managing DOX-induced cardiac complications, thereby improving the safety and efficacy of cancer treatments.

Amifostine attenuates bleomycin-induced pulmonary fibrosis in mice through inhibition of the PI3K/Akt/mTOR signaling pathway

Amifostine is a normal cell protection agent, not only used in the adjuvant therapy of lung cancer, ovarian cancer, breast cancer, nasopharyngeal cancer, bone tumor, digestive tract tumor, blood system tumor and other cancers in order to reduce the toxicity of chemotherapy drugs, and recent studies have reported that the drug can also reduce lung tissue damage in patients with pulmonary fibrosis, but its mechanism of action is not yet fully understood. In this study, we explored the potential therapeutic effects and molecular mechanisms of AMI on bleomycin (BLM)-induced pulmonary fibrosis in mice. A mouse model of pulmonary fibrosis was established using BLM. We then assessed histopathological changes, inflammatory factors, oxidative indicators, apoptosis, epithelial-mesenchymal transition, extracellular matrix changes, and levels of phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling pathway-related proteins in the BLM-treated mice to determine the effect of AMI treatment on these factors. BLM-treated mice had substantial lung inflammation and abnormal extracellular matrix deposition. Overall, treatment with AMI significantly improved BLM-induced lung injury and pulmonary fibrosis. More specifically, AMI alleviated BLM-induced oxidative stress, inflammation, alveolar cell apoptosis, epithelial-mesenchymal transition, and extracellular matrix deposition by regulating the PI3K/Akt/mTOR signaling pathway. This finding that AMI can alleviate pulmonary fibrosis in a mouse model by inhibiting activation of the PI3K/Akt/mTOR signaling pathway lays a foundation for potential future clinical application of this agent in patients with pulmonary fibrosis.

Syntaxin17 contributes to obesity cardiomyopathy through promoting mitochondrial Ca2+ overload in a Parkin-MCUb-dependent manner

OBJECTIVE

Uncorrected obesity is accompanied by unfavorable structural and functional changes in the heart, known as obesity cardiomyopathy. Recent evidence has revealed a crucial role for mitochondria-associated endoplasmic reticulum membranes (MAMs) in obesity-induced cardiac complication. Syntaxin 17 (STX17) serves as a scaffolding molecule localized on MAMs although its role in obesity heart complication remains elusive.

METHODS AND MATERIALS

This study examined the role of STX17 in MAMs and mitochondrial Ca²⁺ homeostasis in HFD-induced obesity cardiomyopathy using tamoxifen-induced cardiac-specific STX17 knockout (STX17^cko) and STX17 overexpression mice using intravenously delivered recombinant adeno-associated virus serotype-9 (AAV9-cTNT-STX17).

RESULTS

STX17 levels were significantly elevated in plasma from obese patients and heart tissues of HFD-fed mice. Our data revealed that cardiac STX17 knockout alleviated cardiac remodeling and dysfunction in obese hearts without eliciting any notable effect itself, while STX17 overexpression aggravated cardiac dysfunction in obese mice. STX17 deletion and STX17 overexpression annihilated and aggravated, respectively, HFD-induced oxidative stress (O₂^- production) and mitochondrial injury in the heart. Furthermore, STX17 transfection facilitated obesity-induced MAMs formation in cardiomyocytes and evoked excess mitochondrial Ca²⁺ influx, dependent upon interaction with mitochondrial Ca²⁺ uniporter dominant negative β (MCUb) through Habc domain. Our data also suggested that STX17 promoted ubiquitination and degradation of MCUb through the E3 ligase parkin in the face of palmitate challenging.

CONCLUSION

Taken together, our results identified a novel role for STX17 in facilitating obesity-induced MAMs formation, and subsequently mitochondrial Ca²⁺ overload, mitochondrial O₂^- accumulation, lipid peroxidation, resulting in cardiac impairment. Our findings denoted therapeutic promises of targeting STX17 in obesity.

Integrated strategy of network pharmacology, molecular docking, HPLC-DAD and mice model for exploring active ingredients and pharmacological mechanisms of Penthorum chinense Pursh against alcoholic liver injury

ETHNOPHARMACOLOGICAL RELEVANCE

Penthorum chinense Pursh (PCP, Saxifragaceae) is an edible plant and frequently-used Chinese herbal medicine, and is commonly used as Miao medicine in China. It showed well effect on alcoholic liver injury (ALI), but studies on its active ingredients and mechanisms against ALI remain at the starting stage.

AIM OF THE STUDY

This work aims to explore the active ingredients and pharmacological mechanisms of PCP against ALI.

MATERIALS AND METHODS

First, network pharmacology was applied to decipher the potential active ingredients and pharmacological mechanisms of PCP against ALI by ingredient identification, ADMET evaluation, target identification, network construction and analysis, protein-protein interaction (PPI) analysis, and gene enrichment analysis. Second, molecular docking was used to explore the interaction between key active ingredient and hub protein of PCP against ALI. Then, the ingredient analysis of PCP aqueous extract and semiquantitative analysis of key active ingredient were carried out on HPLC-DAD. Subsequently, mice with ALI were used to investigate the therapeutic effect or verify the predicted mechanisms of PCP or key active ingredient against ALI by analyzing body weight, liver index, ALT and AST activities in serum and liver tissues, oxidation related indices (SOD activity, GSH level and MDA level) in liver tissues, histopathology of liver tissues (oil red O, hematoxylin-eosin and DAB-TUNEL staining), and changes of related proteins (PI3K, Akt, p-Akt, Bax and Bcl-2) in liver tissues with the aid of Western blot.

RESULTS

Network pharmacology showed that the active ingredients and related genes of PCP against ALI comprised 10 ingredients and 52 genes. Based on the result of ingredient analysis of PCP aqueous extract, quercitrin was identified as the key active ingredient of PCP against ALI. PPI analysis indicated that AKT1 was the hub gene of PCP against ALI, and molecular docking suggested that there were good interaction between quercetin and Akt1 protein. Gene enrichment analysis showed that the pivotal molecular mechanism of PCP against ALI might be to inhibit hepatocyte apoptosis via activation of PI3K-Akt signaling pathway. PCP and quercitrin showed anti-ALI effect by offsetting weight loss and increase of liver index, and reversing the imbalance of oxidative stress and histopathological changes of liver tissues (abnormal fatty acid metabolism, hepatic cord swelling and inflammatory cell infiltration) in mice with ALI. PCP caused the decrease of DAB-TUNEL-positive cells, upregulated the anti-apoptotic proteins (PI3K, Akt and p-Akt) levels and the ratio of p-Akt/Akt, and downregulated pro-apoptotic protein (Bax) level and the ratio of Bax/Bcl-2 in liver tissues of mice with ALI, indicating that the mechanism of PCP against ALI involved in inhibiting hepatocyte apoptosis via activation of PI3K-Akt signaling pathway.

CONCLUSION

PCP and quercitrin showed well anti-ALI effect. The key active ingredient of PCP against ALI was identified as quercitrin. The underlying pharmacological mechanisms of PCP against ALI may be related to PI3K-Akt signaling pathway-mediated inhibition of hepatocyte apoptosis. This work provided new evidence to support the application of PCP in treatment of ALI, and a research basis for the research and development of functional foods or drugs against ALI from PCP.

The Potential Role of Apigenin in Cancer Prevention and Treatment

Cancer is the leading cause of death worldwide. In spite of advances in the treatment of cancer, currently used treatment modules including chemotherapy, hormone therapy, radiation therapy and targeted therapy causes adverse effects and kills the normal cells. Therefore, the goal of more effective and less side effects-based cancer treatment approaches is still at the primary position of present research. Medicinal plants or their bioactive ingredients act as dynamic sources of drugs due to their having less side effects and also shows the role in reduction of resistance against cancer therapy. Apigenin is an edible plant-derived flavonoid that has received significant scientific consideration for its health-promoting potential through modulation of inflammation, oxidative stress and various other biological activities. Moreover, the anti-cancer potential of apigenin is confirmed through its ability to modulate various cell signalling pathways, including tumor suppressor genes, angiogenesis, apoptosis, cell cycle, inflammation, apoptosis, PI3K/AKT, NF-κB, MAPK/ERK and STAT3 pathways. The current review mainly emphases the potential role of apigenin in different types of cancer through the modulation of various cell signaling pathways. Further studies based on clinical trials are needed to explore the role of apigenin in cancer management and explain the possible potential mechanisms of action in this vista.

Induction of P-glycoprotein expression by dandelion in tumor and heart tissues: Impact on the anti-tumor activity and cardiotoxicity of doxorubicin

BACKGROUND

Previously, we have investigated the anti-tumor activity and mechanism through which dandelion acts against triple-negative breast cancer (TNBC). However, traditional Chinese medicine is mostly accepted as an adjunct therapy during chemotherapy in clinical practice. So far, little is known about the effects of dandelion in conjunction with chemotherapeutic drugs.

PURPOSE

To investigate the effects of dandelion on the anti-tumor activity and cardiotoxicity of doxorubicin (DOX), and to further explore the molecular mechanisms through which these effects occur.

STUDY DESIGN

At the beginning of this study, dandelion was observed to alleviate DOX-induced cardiotoxicity and reduce the anti-tumor activity of DOX. Subsequently, we investigated whether the resistance to DOX mediated by P-glycoprotein was involved in the above effects.

METHODS

The cardioprotective effect of dandelion was investigated on DOX-treated mice by histological analysis, myocardial enzyme assays, and an untargeted metabolomics study based on LC-Q-TOF/MS. TNBC cell lines and 4T1 tumor-bearing mice were employed to investigate the combined anti-tumor activity. Laser scanning confocal microscope and a flow cytometry analysis were employed to measure the intracellular accumulation of DOX. A specific, sensitive, and rapid LC-MS/MS method was developed to detect the efflux of DOX from cells. Expression of P-glycoprotein in mouse tumor and heart tissues was detected via Western blotting analysis.

RESULTS

Dandelion was found to significantly alleviate DOX-induced cardiotoxicity, as was evidenced by improved cardiomyocyte morphology, decreased LDH and CK-MB release, and adjusted metabolic biomarker levels. However, in vitro and in vivo studies showed that dandelion could reduce the anti-tumor activity of DOX. This counteraction was achieved by activating of the drug efflux transporter P-glycoprotein, thereby promoting the efflux of DOX from cells and reducing the intracellular accumulation of DOX. Moreover, the activation of P-glycoprotein by dandelion in mouse heart tissue was also observed, thus suggesting that the decrease of cardiac DOX accumulation plays an important role in the cardioprotective effect of dandelion.

CONCLUSION

Dandelion can activate the P-glycoprotein in heart and tumor tissues, which ameliorates DOX-induced cardiotoxicity but attenuates DOX cytotoxicity toward TNBC. Our findings have important implications for the correct clinical use of dandelion.

Danhong injection attenuates doxorubicin-induced cardiotoxicity in rats via suppression of apoptosis: network pharmacology analysis and experimental validation

Doxorubicin (DOX) is a potent chemotherapeutic agent that is used against various types of human malignancies. However, the associated risk of cardiotoxicity has limited its clinical application. Danhong injection (DHI) is a Chinese medicine with multiple pharmacological activities and is widely used for treating cardiovascular diseases. The aim of the present study was to evaluate the potential protective effect of DHI on DOX-induced cardiotoxicity in vivo and to investigate the possible underlying mechanisms. First, a sensitive and reliable HPLC−ESI-Q-TOF-MS/MS method was developed to comprehensively analyze the chemical compositions of DHI. A total of 56 compounds were identified, including phenolic acids, tanshinones, and flavonoids. Then, a DOX-induced chronic cardiotoxicity rat model was established to assess the therapeutic effect of DHI. As a result, DHI administration prevented the reduction in body weight and heart weight, and improved electrocardiogram performance. Additionally, the elevated levels of serum biochemical indicators were reduced, and the activities of oxidative enzymes were restored in the DOX-DHI group. Network pharmacology analysis further revealed that these effects might be attributed to 14 active compounds (e.g., danshensu, salvianolic acid A, salvianolic acid B, rosmarinic acid, and tanshinone IIA) and 15 potential targets (e.g., CASP3, SOD1, NOS3, TNF, and TOP2A). The apoptosis pathway was highly enriched according to the KEGG analysis. Molecular docking verified the good binding affinities between the active compounds and the corresponding apoptosis targets. Finally, experimental validation demonstrated that DHI treatment significantly increased the Bcl-2 level and suppressed DOX-induced Bax and caspase-3 expression in rat heart tissue. Furthermore, DHI treatment obviously decreased the apoptosis rate of DOX-treated H9c2 cells. These results indicate that DHI attenuated DOX-induced cardiotoxicity via regulating the apoptosis pathway. The present study suggested that DHI is a promising agent for the prevention of DOX-induced cardiotoxicity.

Protective Roles of Apigenin Against Cardiometabolic Diseases: A Systematic Review

Apigenin is a flavonoid with antioxidant, anti-inflammatory, and anti-apoptotic activity. In this study, the potential effects of apigenin on cardiometabolic diseases were investigated in vivo and in vitro. Potential signaling networks in different cell types induced by apigenin were identified, suggesting that the molecular mechanisms of apigenin in cardiometabolic diseases vary with cell types. Additionally, the mechanisms of apigenin-induced biological response in different cardiometabolic diseases were analyzed, including obesity, diabetes, hypertension and cardiovascular diseases. This review provides novel insights into the potential role of apigenin in cardiometabolic diseases.

The Role of Flavonoids as a Cardioprotective Strategy against Doxorubicin-Induced Cardiotoxicity: A Review

Doxorubicin is a widely used and promising anticancer drug; however, a severe dose-dependent cardiotoxicity hampers its therapeutic value. Doxorubicin may cause acute and chronic issues, depending on the duration of toxicity. In clinical practice, the accumulative toxic dose is up to 400 mg/m² and increasing the dose will increase the probability of cardiac toxicity. Several molecular mechanisms underlying the pathogenesis of doxorubicin cardiotoxicity have been proposed, including oxidative stress, topoisomerase beta II inhibition, mitochondrial dysfunction, Ca²⁺ homeostasis dysregulation, intracellular iron accumulation, ensuing cell death (apoptosis and necrosis), autophagy, and myofibrillar disarray and loss. Natural products including flavonoids have been widely studied both in cell, animal, and human models which proves that flavonoids alleviate cardiac toxicity caused by doxorubicin. This review comprehensively summarizes cardioprotective activity flavonoids including quercetin, luteolin, rutin, apigenin, naringenin, and hesperidin against doxorubicin, both in in vitro and in vivo models.

Phytochemicals: Potential Therapeutic Modulators of Radiation Induced Signaling Pathways

Ionizing radiation results in extensive damage to biological systems. The massive amount of ionizing radiation from nuclear accidents, radiation therapy (RT), space exploration, and the nuclear battlefield leads to damage to biological systems. Radiation injuries, such as inflammation, fibrosis, and atrophy, are characterized by genomic instability, apoptosis, necrosis, and oncogenic transformation, mediated by the activation or inhibition of specific signaling pathways. Exposure of tumors or normal cells to different doses of ionizing radiation could lead to the generation of free radical species, which can release signal mediators and lead to harmful effects. Although previous FDA-approved agents effectively mitigate radiation-associated toxicities, their use is limited due to their high cellular toxicities. Preclinical and clinical findings reveal that phytochemicals derived from plants that exhibit potent antioxidant activities efficiently target several signaling pathways. This review examined the prospective roles played by some phytochemicals in altering signal pathways associated with radiation response.

Chemoprotective and chemosensitizing effects of apigenin on cancer therapy

BACKGROUND

Therapeutic resistance to radiation and chemotherapy is one of the major obstacles in cancer treatment. Although synthetic radiosensitizers are pragmatic solution to enhance tumor sensitivity, they pose concerns of toxicity and non-specificity. In the last decades, scientists scrutinized novel plant-derived radiosensitizers and chemosensitizers, such as flavones, owing to their substantial physiological effects like low toxicity and non-mutagenic properties on the human cells. The combination therapy with apigenin is potential candidate in cancer therapeutics. This review explicates the combinatorial strategies involving apigenin to overcome drug resistance and boost the anti-cancer properties.

METHODS

We selected full-text English papers on international databases like PubMed, Web of Science, Google Scholar, Scopus, and ScienceDirect from 1972 up to 2020. The keywords included in the search were: Apigenin, Chemoprotective, Chemosensitizing, Side Effects, and Molecular Mechanisms.

RESULTS

In this review, we focused on combination therapy, particularly with apigenin augmenting the anti-cancer effects of chemo drugs on tumor cells, reduce their side effects, subdue drug resistance, and protect healthy cells. The reviewed research data implies that these co-therapies exhibited a synergistic effect on various cancer cells, where apigenin sensitized the chemo drug through different pathways including a significant reduction in overexpressed genes, AKT phosphorylation, NFκB, inhibition of Nrf2, overexpression of caspases, up-regulation of p53 and MAPK, compared to the monotherapies. Meanwhile, contrary to the chemo drugs alone, combined treatments significantly induced apoptosis in the treated cells.

CONCLUSION

Briefly, our analysis proposed that the combination therapies with apigenin could suppress the unwanted toxicity of chemotherapeutic agents. It is believed that these expedient results may pave the path for the development of drugs with a high therapeutic index. Nevertheless, human clinical trials are a prerequisite to consider the potential use of apigenin in the prevention and treatment of various cancers. Conclusively, the clinical trials to comprehend the role of apigenin as a chemoprotective agent are still in infancy.

Cardiotoxicity of Antineoplastic Therapies and Applications of Induced Pluripotent Stem Cell-Derived Cardiomyocytes

The therapeutic landscape for the treatment of cancer has evolved significantly in recent decades, aided by the development of effective oncology drugs. However, many cancer drugs are often poorly tolerated by the body and in particular the cardiovascular system, causing adverse and sometimes fatal side effects that negate the chemotherapeutic benefits. The prevalence and severity of chemotherapy-induced cardiotoxicity warrants a deeper investigation of the mechanisms and implicating factors in this phenomenon, and a consolidation of scientific efforts to develop mitigating strategies. Aiding these efforts is the emergence of induced pluripotent stem cells (iPSCs) in recent years, which has allowed for the generation of iPSC-derived cardiomyocytes (iPSC-CMs): a human-based, patient-derived, and genetically variable platform that can be applied to the study of chemotherapy-induced cardiotoxicity and beyond. After surveying chemotherapy-induced cardiotoxicity and the associated chemotherapeutic agents, we discuss the use of iPSC-CMs in cardiotoxicity modeling, drug screening, and other potential applications. Improvements to the iPSC-CM platform, such as the development of more adult-like cardiomyocytes and ongoing advances in biotechnology, will only enhance the utility of iPSC-CMs in both basic science and clinical applications.

Epithelial-to-Mesenchymal Transition Is Not a Major Modulating Factor in the Cytotoxic Response to Natural Products in Cancer Cell Lines

Numerous natural products exhibit antiproliferative activity against cancer cells by modulating various biological pathways. In this study, we investigated the potential use of eight natural compounds (apigenin, curcumin, epigallocatechin gallate, fisetin, forskolin, procyanidin B2, resveratrol, urolithin A) and two repurposed agents (fulvestrant and metformin) as chemotherapy enhancers and mesenchymal-to-epithelial (MET) inducers of cancer cells. Screening of these compounds in various colon, breast, and pancreatic cancer cell lines revealed anti-cancer activity for all compounds, with curcumin being the most effective among these in all cell lines. Although some of the natural products were able to induce MET in some cancer cell lines, the MET induction was not related to increased synergy with either 5-FU, irinotecan, gemcitabine, or gefitinib. When synergy was observed, for example with curcumin and irinotecan, this was unrelated to MET induction, as assessed by changes in E-cadherin and vimentin expression. Our results show that MET induction is compound and cell line specific, and that MET is not necessarily related to enhanced chemosensitivity.

Curcumin-coated gold nanoparticles attenuate doxorubicin-induced cardiotoxicity via regulating apoptosis in a mouse model

Doxorubicin (DOX) is one of the most widely used chemotherapy agents; however, its nonselective effect causes cardiotoxicity. Curcumin (Cur), a well known dietary polyphenol, could exert a significant cardioprotective effect, but the biological application of this substance is limited by its chemical insolubility. To overcome this limitation, in this study, we synthesised gold nanoparticles based on Cur (Cur-AuNPs). Ultraviolet-visible (UV-Vis) absorbance spectroscopy and transmission electron microscopy (TEM) were performed for the characterisation of synthesised NPs, and Fourier transform infrared (FTIR) spectroscopy were applied to detect Cur on the surface of AuNPs. Its cytotoxicity effect on H9c2 cells was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The biological efficacy of Cur-AuNPs was assessed after acute cardiotoxicity induction in BALB/c mice with DOX injection. The serum biomarkers, myocardial histological changes, and cardiomyocyte apoptosis were then measured. The results revealed that the heart protection by Cur-AuNPs is more effective than Cur alone. Heart protective effect of Cur-AuNPs was evident both in the short-term (24 hours) and long-term (14 days) study. The results of Cur-AuNPs400 after 24 hours of toxicity induction displayed the reduction of the cardiac injury serum biomarkers (LDH, CK-MB, cTnI, ADT, and ALT) and apoptotic proteins (Bax and Caspase-3), as well as increase of Bcl-2 anti-apoptotic proteins without any sign of interfibrillar haemorrhage and intercellular spaces in the heart tissue microscopic images. Our long-term study signifies that Cur-AuNPs400 in DOX-intoxicated mice could successfully inhibit body and heart weight loss in comparison to DOX group.

Dietary Flavonoids: Cardioprotective Potential with Antioxidant Effects and Their Pharmacokinetic, Toxicological and Therapeutic Concerns

Flavonoids comprise a large group of structurally diverse polyphenolic compounds of plant origin and are abundantly found in human diet such as fruits, vegetables, grains, tea, dairy products, red wine, etc. Major classes of flavonoids include flavonols, flavones, flavanones, flavanols, anthocyanidins, isoflavones, and chalcones. Owing to their potential health benefits and medicinal significance, flavonoids are now considered as an indispensable component in a variety of medicinal, pharmaceutical, nutraceutical, and cosmetic preparations. Moreover, flavonoids play a significant role in preventing cardiovascular diseases (CVDs), which could be mainly due to their antioxidant, antiatherogenic, and antithrombotic effects. Epidemiological and in vitro/in vivo evidence of antioxidant effects supports the cardioprotective function of dietary flavonoids. Further, the inhibition of LDL oxidation and platelet aggregation following regular consumption of food containing flavonoids and moderate consumption of red wine might protect against atherosclerosis and thrombosis. One study suggests that daily intake of 100 mg of flavonoids through the diet may reduce the risk of developing morbidity and mortality due to coronary heart disease (CHD) by approximately 10%. This review summarizes dietary flavonoids with their sources and potential health implications in CVDs including various redox-active cardioprotective (molecular) mechanisms with antioxidant effects. Pharmacokinetic (oral bioavailability, drug metabolism), toxicological, and therapeutic aspects of dietary flavonoids are also addressed herein with future directions for the discovery and development of useful drug candidates/therapeutic molecules.

Rationalizing the therapeutic potential of apigenin against cancer

BACKGROUND

Despite the remarkable advances made in the diagnosis and treatment of cancer during the past couple of decades, it remains the second largest cause of mortality in the world, killing approximately 9.6 million people annually. The major challenges in the treatment of the advanced stage of this disease are the development of chemoresistance, severe adverse effects of the drugs, and high treatment cost. Therefore, the development of drugs that are safe, efficacious, and cost-effective remains a 'Holy Grail' in cancer research. However, the research over the past four decades shed light on the cancer-preventive and therapeutic potential of natural products and their underlying mechanism of action. Apigenin is one such compound, which is known to be safe and has significant potential in the prevention and therapy of this disease.

AIM

To assess the literature available on the potential of apigenin and its analogs in modulating the key molecular targets leading to the prevention and treatment of different types of cancer.

METHOD

A comprehensive literature search has been carried out on PubMed for obtaining information related to the sources and analogs, chemistry and biosynthesis, physicochemical properties, biological activities, bioavailability and toxicity of apigenin.

KEY FINDINGS

The literature search resulted in many in vitro, in vivo and a few cohort studies that evidenced the effectiveness of apigenin and its analogs in modulating important molecular targets and signaling pathways such as PI3K/AKT/mTOR, JAK/STAT, NF-κB, MAPK/ERK, Wnt/β-catenin, etc., which play a crucial role in the development and progression of cancer. In addition, apigenin was also shown to inhibit chemoresistance and radioresistance and make cancer cells sensitive to these agents. Reports have further revealed the safety of the compound and the adaptation of nanotechnological approaches for improving its bioavailability.

SIGNIFICANCE

Hence, the present review recapitulates the properties of apigenin and its pharmacological activities against different types of cancer, which warrant further investigation in clinical settings.

Natural compounds against cytotoxic drug-induced cardiotoxicity: A review on the involvement of PI3K/Akt signaling pathway

Cardiotoxicity is a critical concern in the use of several cytotoxic drugs. Induction of apoptosis, inflammation, and autophagy following dysregulation of the PI3K/Akt signaling pathway contributes to the cardiac damage induced by these drugs. Several natural compounds (NCs), including ferulic acid, gingerol, salvianolic acid B, paeonol, apigenin, calycosin, rutin, neferine, higenamine, vincristine, micheliolide, astragaloside IV, and astragalus polysaccharide, have been reported to suppress cytotoxic drug-induced cardiac injury. This article reviews these NCs that have been reported to have a protective effect against cytotoxic drug-induced cardiotoxicity through regulation of the PI3K/Akt signaling pathway.

Autophagy and cardiac diseases: Therapeutic potential of natural products

The global incidence of cardiac diseases is expected to increase in the coming years, imposing a substantial socioeconomic burden on healthcare systems. Autophagy is a tightly regulated lysosomal degradation mechanism important for cell survival, homeostasis, and function. Accumulating pieces of evidence have indicated a major role of autophagy in the regulation of cardiac homeostasis and function. It is well established that dysregulation of autophagy in cardiomyocytes is involved in cardiac hypertrophy, myocardial infarction, diabetic cardiomyopathy, and heart failure. In this sense, autophagy seems to be an attractive therapeutic target for cardiac diseases. Recently, multiple natural products/phytochemicals, such as resveratrol, berberine, and curcumin have been shown to regulate cardiomyocyte autophagy via different pathways. The autophagy-modifying capacity of these compounds should be taken into consideration for designing novel therapeutic agents. This review focuses on the role of autophagy in various cardiac diseases and the pharmacological basis and therapeutic potential of reported natural products in cardiac diseases by modifying autophagic processes.

Molecular Mechanisms of Cardiomyocyte Death in Drug-Induced Cardiotoxicity

Homeostatic regulation of cardiomyocytes plays a crucial role in maintaining the normal physiological activity of cardiac tissue. Severe cardiotoxicity results in cardiac diseases including but not limited to arrhythmia, myocardial infarction and myocardial hypertrophy. Drug-induced cardiotoxicity limits or forbids further use of the implicated drugs. Such drugs that are currently available in the clinic include anti-tumor drugs (doxorubicin, cisplatin, trastuzumab, etc.), antidiabetic drugs (rosiglitazone and pioglitazone), and an antiviral drug (zidovudine). This review focused on cardiomyocyte death forms and related mechanisms underlying clinical drug-induced cardiotoxicity, including apoptosis, autophagy, necrosis, necroptosis, pryoptosis, and ferroptosis. The key proteins involved in cardiomyocyte death signaling were discussed and evaluated, aiming to provide a theoretical basis and target for the prevention and treatment of drug-induced cardiotoxicity in the clinical practice.

Acylated Ghrelin Protects the Hearts of Rats from Doxorubicin-Induced Fas/FasL Apoptosis by Stimulating SERCA2a Mediated by Activation of PKA and Akt

This study investigated if the cardioprotective effect of acylated ghrelin (AG) against doxorubicin (DOX)-induced cardiac toxicity in rats involves inhibition of Fas/FasL-mediated cell death. It also investigated if such an effect is mediated by restoring Ca⁺² homeostasis from the aspect of stimulation of SERCA2a receptors. Adult male Wistar rats were divided into 4 groups (20 rats/each) as control, control + AG, DOX, and DOX + AG. AG was co-administered to all rats consecutively for 35 days. In addition, isolated cardiomyocytes were cultured and treated with AG in the presence or absence of DOX with or without pre-incubation with [D-Lys3]-GHRP-6 (a AG receptor antagonist), VIII (]an Akt inhibitor), or KT-5720 (a PKA inhibitor). AG increased LVSP, dp/dt_max, and dp/dt_min in both control and DOX-treated animals and improved cardiac ultrastructural changes in DOX-treated rats. It also inhibited ROS in control rats and lowered LVEDP, intracellular levels of ROS and Ca²⁺, and activity of calcineurin in LVs of DOX-treated rats. Concomitantly, it inhibited LV NFAT-4 nuclear translocation and downregulated their protein levels of Fas and FasL. Mechanistically, in control or DOX-treated hearts or cells, AG upregulated the levels of SERCA2a and increased the activities of PKA and Akt, leading to increase phosphorylation of phospholamban at Ser¹⁶ and Thr¹⁷. All these effects were abolished by D-Lys3-GHRP-6, VIII, or KT-5720 and were independent of food intake or GH/IGF-1. In conclusion, AG cardioprotection against DOX involves inhibition of extrinsic cell death and restoring normal Ca⁺² homeostasis.

Polydatin protects H9c2 cells from hypoxia-induced injury via up-regulating long non-coding RNA DGCR5

Polydatin (PD), a monocrystalline polyphenolic drug mainly found in the roots of Polygonum cuspidatum, has various pharmacological activities. Long non-coding RNAs (lncRNA) DiGeorge syndrome critical region gene 5 (DGCR5) was found to participate in the suppression of multiple cancers. Here, we proposed to study the effect of PD on myocardial infarction (MI) by inducing DGCR5. CCK-8 assay was performed to detect the viability of H9c2 cells. Flow cytometry was utilized to test apoptosis of H9c2 cells. These results determined the optimal concentration and effect time of hypoxia as well as PD. Si-DGCR5 was transfected into cells and the expression level was determined by qRT-PCR. Western blot was utilized to evaluate the expression of apoptosis-related proteins, Bcl-2, Bax, and cleaved-caspase-3, as well as autophagy-associated proteins including Beclin-1, p62, and LC3-II/LC3-I. As a result, PD efficiently attenuated hypoxia-induced apoptosis and autophagy in H9c2 cells. The expression of DGCR5 was down-regulated by hypoxia and up-regulated by PD. Besides, knocking-down the expression of DGCR5 inhibited the protection of PD in H9c2 cells. In addition, PD up-regulated the accumulation of DGCR5, DGCR5 decreased the expression of Bcl-2 and p62, raised the expression of Bax and cleaved-caspase-3, and the proportion of LC3-II/LC3-I. PD stimulated the PI3K/AKT/mTOR and MEK/ERK signaling pathways via up-regulating the expression of DGCR5. Our data demonstrated that PD reduced cell apoptosis and autophagy induced by hypoxia in cardiomyocytes. Moreover, PD activated PI3K/AKT/mTOR and MEK/ERK signaling pathways by up-regulating the expression of DGCR5.

Apigenin attenuates doxorubicin induced cardiotoxicity via reducing oxidative stress and apoptosis in male rats

AIMS

Doxorubicin, an antibiotic belonging to anthracycline family, has been used for treatment of malignancies. Cardiotoxicity is the main adverse effect of doxorubicin. Apigenin, as a flavonoid, has antioxidant, anti-inflammatory and anti-tumoral properties. The aim of this study was the assessment of any protective effect of apigenin on cardiotoxicity induced by doxorubicin.

MAIN METHODS

40 male Wistar rats were randomly divided into 4 groups: control, cardiotoxicity (DOX), apigenin treated group (DOX + Api 25) and apigenin group (Api 25). At the end of the experiment, the markers of cardiac function (%EF, %FS, LVIDs, LVIDd), cardiac and liver injury (LDH, CK-MB, cTn-I, ALT, and AST), cardiac apoptosis (Bax, Bcl-2 and Caspase3), cardiac oxidative stress (SOD, GSH, MDA) and cardiac fibrosis were measured.

KEY FINDINGS

Apigenin improved cardiac functional parameters. The levels of cardiac and liver injury markers were significantly decreased in DOX + Api 25 compared to DOX. Treatment with apigenin caused significant decrease in percentage of cardiac fibrosis in comparison with DOX. Apigenin in DOX + Api 25 group led to significant decrease in apoptotic proteins (Casp3, Bax) and a significant increase in anti-apoptotic proteins (Bcl2). In apigenin treatment groups, SOD levels significantly increased while a significant decrease was observed in MDA. The amount of GSH in DOX + Api 25 had no significant change in comparison to control and Api 25 groups.

SIGNIFICANCE

Apigenin reduced cardiac injuries induced by DOX through anti-fibrotic, antioxidant and anti-apoptotic properties. It seems that apigenin prevents cardiac injuries and improves cardiac function.

Vaspin Prevents Tumor Necrosis Factor-α-Induced Apoptosis in Cardiomyocytes by Promoting Autophagy

Visceral adipose tissue-derived serine protease inhibitor (Vaspin) is an adipocytokine that has been shown to exert anti-inflammatory effects and inhibits apoptosis under diabetic conditions. This study was designed to investigate the impact of vaspin on autophagy in tumor necrosis factor (TNF)-α-induced injury in cardiomyocytes and its cardioprotective effects in the pathogenesis of diabetic cardiomyopathy (DCM). H9C2 cells were treated with TNF-α with or without vaspin in vitro. Tumor necrosis factor-α treatment inhibited autophagy and promoted apoptosis in H9C2 cells after stimulating for 24 hours. Pretreatment with vaspin significantly mitigated apoptosis induced by TNF-α partly because of augment effects of vaspin on autophagy as demonstrated by a higher ratio of LC3-II/LC3-I, higher expression of Beclin-1, and increased autophagosomes formation. Furthermore, the AKT agonist IGF-1 significantly reversed the effect of vaspin on autophagy. In vivo DCM model was also developed by treating rats with streptozotocin followed by intraperitoneal injection with vaspin. In DCM rats, upregulation of vaspin reversed cardiac dysfunction, as identified by increased left ventricular ejection fractions and fractional shortening levels, a higher Em/Am ratio, and lower levels of TNF-α, lactate dehydrogenase, creatine kinase, and creatine kinase-myocardial isoenzyme. In conclusion, vaspin attenuated the TNF-α-induced apoptosis by promoting autophagy probably through inhibiting the PI3K/AKT/mTOR pathway and further ameliorated the cardiac dysfunction in DCM rats.

Alisol B 23‑acetate inhibits the viability and induces apoptosis of non‑small cell lung cancer cells via PI3K/AKT/mTOR signal pathway

The aim of the present study was to investigate the effects of alisol B 23‑acetate (AB23A) on inhibiting the viability and inducing apoptosis of human non‑small cell lung cancer (NSCLC) cells and the anticancer mechanisms of AB23A in vitro. The viability of A549 cells following treatment with different doses of AB23A was examined using a Cell Counting Kit‑8 assay. Subsequently, apoptosis and the cell cycle were detected using flow cytometric analysis. The effect of AB23A on migration and invasion of A549 cells was detected by wound healing and Transwell assays. Western blotting was performed to determine the relative expression of Bax/Bcl‑2, phosphatidylinositol 3‑kinase (PI3K), protein kinase B (AKT) and mammalian target of rapamycin (mTOR). AB23A markedly inhibited the viability enhanced apoptosis of A549 cells and arrested the cell cycle in G1 phase. Additionally, AB23A upregulated the ratio of Bax/Bcl‑2 in the A549 cells in a concentration‑dependent manner. The results of wound healing and Transwell assays indicated that AB23A also suppresses the migration and invasion ability of A549 cells. Furthermore, AB23A reduced the protein levels of phosphorylated AKT, PI3K and mTOR. In conclusion, AB23A exerted anti‑cancer activity via inhibiting cells viability, migration and invasion, and promoting apoptosis. Therefore, AB23A is a potential antitumor drug for the treatment of NSCLC.

miR-181b-5p suppresses starvation-induced cardiomyocyte autophagy by targeting Hspa5

This study aimed to investigate the role of microRNA-181b-5p (miR-181b-5p) in starvation-induced cardiomyocyte autophagy by targeting heat shock protein family A member 5 (Hspa5). For this purpose, H9c2 cardiomyocytes and neonatal rat ventricular myocytes (NRVMs) were glucose-starved in Earle's Balanced Salt Solution (EBSS) for different periods of time (0, 2, 4, 6 and 8 h). RT-qPCR analysis was performed to examine the expression of miR-181b-5p in the different groups. Immunofluorescence was performed to detect the expression of LC3. In addition, the H9c2 cardiomyo-cytes and NRVMs were transfected with miR-181b-5p mimic, miR-181b-5p inhibitor, siHspa5 or their respective controls. An MTT assay was performed to measure cell proliferation in the different groups. Western blot analysis was performed to determine the expression of Beclin-1, Hspa5, phosphorylated phosphoinositide 3-kinase PI3K (p-PI3K), phosphorylated Akt (p-Akt), phosphorylated mammalian target of rapamycin (p-mTOR), Bcl-2, Bax and cleaved caspase-3. Flow cytometry was performed to assess cell apoptosis. A luciferase reporter assay was performed to determine whether Hspa5 is a direct target of miR-181b-5p. The results revealed that the down-regulation of miR-181b-5p promoted cell autophagy in the cardiomyocytes. Moreover, miR-181b-5p negatively regulated Beclin-1 and Hspa5. Beclin-1 is a well-known autophagy- and apoptosis-related protein. In addition, cell apoptosis was attenuated by the decreased expression of miR-181b-5p in the cardiomyocytes. Bcl-2 prevented apoptosis and autophagy by binding to Bax and Bcl-2, respectively. The upregulation of miR-181b-5p inhibited autophagy and promoted apoptosis via Hspa5. miR-181b-5p inhibition promoted p-mTOR, p-Akt and p-PI3K expression via Hspa5. The results of luciferase reporter assay also confirmed that Hspa5 is a direct target of miR-181b-5p. On the whole, the findings of this study suggest that miR-181b-5p contributes to starvation-induced autophagy and apoptosis in cardiomyocytes by directly targeting Hspa5 via the PI3K/Akt/mTOR signaling pathway.

Norcantharidin inhibits viability and induces cell cycle arrest and apoptosis in osteosarcoma

Osteosarcoma is the most frequent malignant bone tumor in children and adolescents. Norcantharidin (NCTD) is a purified component from blister beetles and has been identified to exert antitumor effects in a variety of cancer types. However, the antitumor effect of NCTD in osteosarcoma remains to be elucidated. In the current study, it was first demonstrated that NCTD inhibited proliferation and induced G2/M-phase arrest and cell apoptosis in human osteosarcoma cells. Furthermore, NCTD significantly decreased the phosphorylation of Akt and the mammalian target of rapamycin in human osteosarcoma cells. These results suggest that NCTD is a promising candidate for the treatment of osteosarcoma patients in the future.

Humanin analog enhances the protective effect of dexrazoxane against doxorubicin-induced cardiotoxicity

The chemotherapeutic effect of doxorubicin (Dox) is limited by cumulative dose-dependent cardiotoxicity in cancer survivors. Dexrazoxane (DRZ) is approved to prevent Dox-induced cardiotoxicity. Humanin and its synthetic analog HNG have a cytoprotective effect on the heart. To investigate the cardioprotective efficacy of HNG alone or in combination with DRZ against Dox-induced cardiotoxicity, 80 adult male mice were randomly divided into 8 groups to receive the following treatments via intraperitoneal injection: saline dailym HNG (5 mg/kg) daily, DRZ (60 mg/kg) weekly, Dox (3 mg/kg) weekly, DRZ + HNG, Dox + HNG, Dox + DRZ, and Dox + HNG + DRZ. Echocardiograms were performed before and at 4, 8, and 9.5 wk after the beginning of treatment. All mice were euthanized at 10 wk. In the absence of Dox, HNG, DRZ, or DRZ + HNG had no adverse effect on the heart. Dox treatment caused decreases in ejection fraction and cardiac mass and increases in cardiomyocyte apoptosis and intracardiac fibrosis. HNG or DRZ alone blunted the Dox-induced decrease in left ventricle posterior wall thickness and modestly ameliorated the Dox-induced decrease in ejection fraction. HNG + DRZ significantly ameliorated Dox-induced decreases in ejection function, cardiac fibrosis, and cardiac mass. Using a targeted analysis for the mitochondrial gene array and protein expression in heart tissues, we demonstrated that HNG + DRZ reversed DOX-induced altered transcripts that were biomarkers of cardiac damage and uncoupling protein-2. We conclude that HNG enhances the cardiac protective effect of DRZ against Dox-induced cardiotoxicity. HNG + DRZ protects mitochondria from Dox-induced cardiac damage and blunts the onset of cardiac dysfunction. Thus, HNG may be an adjuvant to DRZ in preventing Dox-induced cardiotoxicity. NEW & NOTEWORTHY Doxorubicin (Dox) is commonly used for treating a wide range of human cancers. However, cumulative dosage-dependent carditoxicity often limits its clinical applications. We demonstrated in this study that treating young adult male mice with synthetic humanin analog enhanced the cardiac protective effect of dexrazoxane against chemotherapeutic agent Dox-induced cardiac dysfunction. Thus, humanin analog can potentially serve as an adjuvant to dexrazoxane in more effectively preventing Dox-induced cardiac dysfunction and cardiomyopathy.

Apigenin suppresses the apoptosis of H9C2 rat cardiomyocytes subjected to myocardial ischemia‑reperfusion injury via upregulation of the PI3K/Akt pathway

Apigenin, a flavonoid with multiple physiological and pharmacological activities, is associated with the prevention of cardiovascular diseases. The present study aimed to examine the roles and mechanisms of apigenin in the apoptosis of H9C2 rat cardiomyocytes, which were subjected to myocardial ischemia-reperfusion (MI/R) injury. Cell viability, reactive oxygen species (ROS), mitochondrial membrane potential (MMP) and cellular apoptosis were evaluated using cell counting kit-8 assays and flow cytometry. The content/activity of oxidative stress markers was determined using commercial kits. Western blot analysis and reverse transcription-quantitative polymerase chain reaction assays were used to measure protein and mRNA expression, respectively. The results demonstrated that apigenin had limited cytotoxicity on the viability of H9C2 rat cardiomyocytes. Apigenin reduced the oxidative stress, ROS production and cellular apoptotic capacity of MI/R-induced H9C2 cells. Apigenin additionally increased the MMP level of MI/R-induced H9C2 cells. Furthermore, apigenin modulated apoptosis-associated protein expression and phosphatidylinositol 3′-kinase (PI3K)/RAC-α serine/threonine-protein kinase (Akt) signaling in MI/R-induced H9C2 cells. Treatment with LY294002 reversed the anti-apoptotic effect of apigenin. In conclusion, apigenin suppressed the apoptosis of H9C2 cells that were subjected to MI/R injury by activating the PI3K/Akt pathway. It was suggested that apigenin may be effective as an MI/R therapy.

Cardiac progenitor cell‑derived exosomes promote H9C2 cell growth via Akt/mTOR activation

Exosomes are cell-derived vesicles released from a variety of mammalian cells that are involved in cell-to-cell signalling. It has been reported that cardiac progenitor cells (CPCs) derived from an adult heart are one of the most promising stem cell types for cardioprotection and repair. The mammalian target of rapamycin (mTOR) signalling pathway is a pivotal regulator in CPCs, therefore, CPC-derived exosomes were used in the present study to investigate whether it can promote H9C2 cell growth through the protein kinase B (PKB, or Akt)/mTOR signalling pathway. The CPCs were isolated from Sprague-Dawley hearts. Following treatment with a specific medium, the exosomes were purified and identified by electron micrograph and western blot assays, using CD63 and CD81 as markers. The methyl-thiazolyl-tetrazolium and 5-ethynyl-2′-deoxyuridine methods were used to detect H9C2 cell growth. The expression of Akt and mTOR were detected by western blot analysis following treatment with 200 or 400 µg/ml of exosomes for 24 or 48 h, respectively. It was found that, compared with higher concentrations of exosomes, prolonging the duration of exposure promoted cell growth. Accordingly, CPC-derived exosomes stimulated the expression of Akt to a marked degree; groups treated with exosomes for 48 h showed higher expression of Akt than those treated for 24 h at the same concentration. mTOR was also stimulated by CPC-derived exosomes. The activation of mTOR increased in accordance with the treatment time at an exosome concentration of 200 µg/ml and decreased with treatment time at an exosome concentration of 400 µg/ml. In conclusion, the present study demonstrated that CPC-derived exosomes promoted H9C2 cell growth via the activation of Akt/mTOR in a time-dependent manner at a relatively low exosome concentration, which may provide a novel therapy for cardiovascular disease.

Apigenin in cancer therapy: anti-cancer effects and mechanisms of action

Apigenin is a common dietary flavonoid that is abundantly present in many fruits, vegetables and Chinese medicinal herbs and serves multiple physiological functions, such as strong anti-inflammatory, antioxidant, antibacterial and antiviral activities and blood pressure reduction. Therefore, apigenin has been used as a traditional medicine for centuries. Recently, apigenin has been widely investigated for its anti-cancer activities and low toxicity. Apigenin was reported to suppress various human cancers in vitro and in vivo by multiple biological effects, such as triggering cell apoptosis and autophagy, inducing cell cycle arrest, suppressing cell migration and invasion, and stimulating an immune response. In this review, we focus on the most recent advances in the anti-cancer effects of apigenin and their underlying mechanisms, and we summarize the signaling pathways modulated by apigenin, including the PI3K/AKT, MAPK/ERK, JAK/STAT, NF-κB and Wnt/β-catenin pathways. We also discuss combinatorial strategies to enhance the anti-cancer effect of apigenin on various cancers and its use as an adjuvant chemotherapeutic agent to overcome cancer drug resistance or to alleviate other adverse effects of chemotherapy. The functions of apigenin against cancer stem cells are also summarized and discussed. These data demonstrate that apigenin is a promising reagent for cancer therapy. Apigenin appears to have the potential to be developed either as a dietary supplement or as an adjuvant chemotherapeutic agent for cancer therapy.