Doxorubicin Is Key for the Cardiotoxicity of FAC (5-Fluorouracil + Adriamycin + Cyclophosphamide) Combination in Differentiated H9c2 Cells

pH-responsive nanogels with enhanced antioxidant and antitumor activities on drug delivery and smart drug release

pH-responsive nanogels have played an increasingly momentous role in tumor treatment. The focus of this study is to design and develop pH-responsive benzimidazole-chitosan quaternary ammonium salt (BIMIXHAC) nanogels for the controlled release of doxorubicin hydrochloride (DOX) while enhancing its hydrophilicity. BIMIXHAC is crosslinked with carboxymethyl chitosan (CMC), hyaluronic acid sodium salt (HA), and sodium alginates (SA) using an ion crosslinking method. The chemical structure of chitosan derivatives was verified by 1H NMR and FT-IR techniques. Compared to hydroxypropyl trimethyl ammonium chloride chitosan (HACC)-based nanogels, BIMIXHAC-based nanogels exhibit better drug encapsulation efficiency and loading capacity (BIMIXHAC-D-HA 91.76 %, and 32.23 %), with pH-responsive release profiles and accelerated release in vitro. The series of nanogels formed by crosslinking with three different polyanionic crosslinkers have different particle size potentials and antioxidant properties. BIMIXHAC-HA, BIMIXHAC-SA and BIMIXHAC-CMC demonstrate favorable antioxidant capability. In addition, cytotoxicity tests showed that BIMIXHAC-based nanogels have high biocompatibility. BIMIXHAC-based nanogels exhibit preferable anticancer effects on MCF-7 and A549 cells. Furthermore, the BIMIXHAC-D-HA nanogel was 2.62 times less toxic than DOX to L929 cells. These results suggest that BIMIXHAC-based nanogels can serve as pH-responsive nanoplatforms for the delivery of anticancer drugs.

Molecular mechanism of empagliflozin cardioprotection in 5-fluorouracil (5-FU)-induced cardiotoxicity via modulation of SGLT2 and TNFα/TLR/NF-κB signaling pathway in rats

One of the commoly used chemotherapeutic agents is 5-Fluorouracil (5-FU). Unfortunately, the clinical administration of 5-FU is complicated with serious cardiotoxic effects and the safe use becomes an urgent task in cardio-oncology. Till now, there are no studies discussed the role of empagliflozin (EMP) against 5-FU cardiotoxicity. Thus, we investigated this effect and the involved mechanisms in 5-FU induced heart injury. Forty male rats of Wistar albino species were used and divided randomly into four groups. Group I is the control group, group II is EMP given group, group III is 5-FU cardiotoxic group and group IV is 5-FU plus EMP group. 5-FU (150 mg/kg) was administered as a single intraperitoneal (i.p.) dose on 1st day to induce cardiotoxicity with or without EMP (30 mg/kg/d) orally for 5 days. The dose of 5-FU is relevant to the human toxic dose. Our data showed that 5-FU given group caused cardiotoxicity with significant increase of serum cardiac enzymes, toll like receptors, enhancement of nuclear factor kappa B (NF-κB), interleukin1β (IL1β), IL6, myeloid-differentiation-factor 88 (MYD88), heart weight, malondialdehyde (MDA), tumor-necrosis-factor-alpha (TNFα), sodium glucose co-transporter 2 (SGLT2), P53 and caspase3 expression with clear histopathological features of cardiotoxicity. Moreover, there is a significant decrease in reduced glutathione (GSH) and total antioxidant capacity (TAC). Interestingly, co-administration of EMP could ameliorate 5-FU induced biochemical and histopathological changes. This effect may be due to modulation of SGLT2, decreasing inflammation, oxidative stress and apoptosis with downregulation of an essential inflammatory cascade that mediates 5-FU cardiotoxicity; TNFα/TLR/NF-κB.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43188-023-00204-1.

14,15-Dihydroxyeicosatrienoic acid, a soluble epoxide hydrolase metabolite in blood, is a predictor of anthracycline-induced cardiotoxicity - a hypothesis generating study

BACKGROUND

Early identification of patients susceptible to chemotherapy-induced cardiotoxicity could lead to targeted treatment to reduce cardiac dysfunction. Rats treated with doxorubicin (DOX), a chemotherapeutic agent, have increased cardiac expression of 14,15-dihydroxyeicosatrienoic acid (14,15-DHET), a bioactive lipid implicated in hypertension and coronary artery disease. However, the utility of 14,15-DHET as plasma biomarkers was not defined. The aim of this study is to investigate if levels of 14,15-DHET are an early blood biomarker to predict the subsequent occurrence of cardiotoxicity in cancer patients after chemotherapy.

METHODS

H9c2 rat cardiomyocytes were treated with DOX (1 μM) for 2 h and levels of 14,15-DHET in cell media was quantified at 2, 6 or 24 h in media after DOX treatment. Similarly, female Sprague-Dawley rats were treated with DOX for two weeks and levels of 14,15-DHET was assessed in plasma at 48 h and 2 weeks after DOX treatment. Changes in brain natriuretic peptide (BNP) mRNA, an early cardiac hypertrophy process, were determined in the H9c2 cells and rat cardiac tissue. Results were confirmed in human subjects by assessment of levels of 14,15-DHET in plasma of breast cancer patients before and after DOX treatment and left ventricular ejection fraction (LVEF), a clinical marker of cardiotoxicity.

RESULTS

Levels of 14,15-DHET in cell media and rat plasma increased ~ 3-fold and was accompanied with increase in BNP mRNA in H9c2 cells and rat cardiac tissue after DOX treatment. In matched plasma samples from breast cancer patients, levels of 14,15-DHET were increased in patients that developed cardiotoxicity at 3 months before occurrence of LVEF decrease.

CONCLUSIONS

Together, these results indicate that levels of 14,15-DHET are elevated prior to major changes in cardiac structure and function after exposure to anthracyclines. Increased levels of 14,15-DHET in plasma may be an important clinical biomarker for early detection of anthracycline-induced cardiotoxicity in cancer patients.

Targeting CAR and Nrf2 improves cyclophosphamide bioactivation while reducing doxorubicin-induced cardiotoxicity in triple-negative breast cancer treatment

Cyclophosphamide (CPA) and doxorubicin (DOX) are key components of chemotherapy for triple-negative breast cancer (TNBC), although suboptimal outcomes are commonly associated with drug resistance and/or intolerable side effects. Through an approach combining high-throughput screening and chemical modification, we developed CN06 as a dual activator of the constitutive androstane receptor (CAR) and nuclear factor erythroid 2-related factor 2 (Nrf2). CN06 enhances CAR-induced bioactivation of CPA (a prodrug) by provoking hepatic expression of CYP2B6, while repressing DOX-induced cytotoxicity in cardiomyocytes in vitro via stimulating Nrf2-antioxidant signaling. Utilizing a multicellular coculture model incorporating human primary hepatocytes, TNBC cells, and cardiomyocytes, we show that CN06 increased CPA/DOX-mediated TNBC cell death via CAR-dependent CYP2B6 induction and subsequent conversion of CPA to its active metabolite 4-hydroxy-CPA, while protecting against DOX-induced cardiotoxicity by selectively activating Nrf2-antioxidant signaling in cardiomyocytes but not in TNBC cells. Furthermore, CN06 preserves the viability and function of human iPSC-derived cardiomyocytes by modulating antioxidant defenses, decreasing apoptosis, and enhancing the kinetics of contraction and relaxation. Collectively, our findings identify CAR and Nrf2 as potentially novel combined therapeutic targets whereby CN06 holds the potential to improve the efficacy/toxicity ratio of CPA/DOX-containing chemotherapy.

Cardiotoxicity of cyclophosphamide's metabolites: an in vitro metabolomics approach in AC16 human cardiomyocytes

Cyclophosphamide is a widely used anticancer and immunosuppressive prodrug that unfortunately causes severe adverse effects, including cardiotoxicity. Although the exact cardiotoxic mechanisms are not completely understood, a link between cyclophosphamide's pharmacologically active metabolites, namely 4-hydroxycyclophosphamide and acrolein, and the toxicity observed after the administration of high doses of the prodrug is likely. Therefore, the objective of this study is to shed light on the cardiotoxic mechanisms of cyclophosphamide and its main biotransformation products, through classic and metabolomics studies. Human cardiac proliferative and differentiated AC16 cells were exposed to several concentrations of the three compounds, determining their basic cytotoxic profile and preparing the next study, using subtoxic and toxic concentrations for morphological and biochemical studies. Finally, metabolomics studies were applied to cardiac cells exposed to subtoxic concentrations of the aforementioned compounds to determine early markers of damage. The cytotoxicity, morphological and biochemical assays showed that 4-hydroxycyclophosphamide and acrolein induced marked cardiotoxicity at µM concentrations (lower than 5 µM), being significantly lower than the ones observed for cyclophosphamide (higher than 2500 μM). Acrolein led to increased levels of ATP and total glutathione on proliferative cells at 25 µM, while no meaningful changes were observed in differentiated cells. Higher levels of carbohydrates and decreased levels of fatty acids and monoacylglycerols indicated a metabolic cardiac shift after exposure to cyclophosphamide's metabolites, as well as a compromise of precursor amino acids used in the synthesis of glutathione, seen in proliferative cells' metabolome. Overall, differences in cytotoxic mechanisms were observed for the two different cellular states used and for the three molecules, which should be taken into consideration in the study of cyclophosphamide cardiotoxic mechanisms.

MicroRNA and Alternative mRNA Splicing Events in Cancer Drug Response/Resistance: Potent Therapeutic Targets

Cancer is a multifaceted disease that involves several molecular mechanisms including changes in gene expression. Two important processes altered in cancer that lead to changes in gene expression include altered microRNA (miRNA) expression and aberrant splicing events. MiRNAs are short non-coding RNAs that play a central role in regulating RNA silencing and gene expression. Alternative splicing increases the diversity of the proteome by producing several different spliced mRNAs from a single gene for translation. MiRNA expression and alternative splicing events are rigorously regulated processes. Dysregulation of miRNA and splicing events promote carcinogenesis and drug resistance in cancers including breast, cervical, prostate, colorectal, ovarian and leukemia. Alternative splicing may change the target mRNA 3'UTR binding site. This alteration can affect the produced protein and may ultimately affect the drug affinity of target proteins, eventually leading to drug resistance. Drug resistance can be caused by intrinsic and extrinsic factors. The interplay between miRNA and alternative splicing is largely due to splicing resulting in altered 3'UTR targeted binding of miRNAs. This can result in the altered targeting of these isoforms and altered drug targets and drug resistance. Furthermore, the increasing prevalence of cancer drug resistance poses a substantial challenge in the management of the disease. Henceforth, molecular alterations have become highly attractive drug targets to reverse the aberrant effects of miRNAs and splicing events that promote malignancy and drug resistance. While the miRNA-mRNA splicing interplay in cancer drug resistance remains largely to be elucidated, this review focuses on miRNA and alternative mRNA splicing (AS) events in breast, cervical, prostate, colorectal and ovarian cancer, as well as leukemia, and the role these events play in drug resistance. MiRNA induced cancer drug resistance; alternative mRNA splicing (AS) in cancer drug resistance; the interplay between AS and miRNA in chemoresistance will be discussed. Despite this great potential, the interplay between aberrant splicing events and miRNA is understudied but holds great potential in deciphering miRNA-mediated drug resistance.

Human Amnion Membrane Proteins Prevent Doxorubicin-Induced Oxidative Stress Injury and Apoptosis in Rat H9c2 Cardiomyocytes

Doxorubicin (DOX) is widely used as an effective chemotherapy agent in cancer treatment. Cardiac toxicity in cancer treatment with DOX demand urgent attention and no effective treatment has been established for DOX-induced cardiomyopathy. It has been well documented that human amniotic membrane proteins (AMPs), extracted from amnion membrane (AM), have antioxidant, anti-apoptotic, and cytoprotective properties. Therefore, in this study, we aimed to investigate the protective effects of AMPs against cardiotoxicity induced by DOX in cultured rat cardiomyocyte cells (H9c2). DOX-induced cell injury was evaluated using multi-parametric assay including thiazolyl blue tetrazolium bromide (MTT), the release of lactic dehydrogenase (LDH), intracellular Ca2+ , reactive oxygen species (ROS) levels, cellular antioxidant status, mitochondrial membrane potential (ΔΨm), malondialdehyde (MDA), and NF-κB p65 DNA-binding activity. Moreover, expression profiling of apoptosis-related genes (P53, Bcl-2, and Bax) and Annexin V by flow cytometry were used for cell apoptosis detection. It was shown that AMPs pretreatment inhibited the cell toxicity induced by DOX. AMPs effectively attenuated the increased levels of LDH, Ca2+ , ROS, and MDA and also simultaneously elevated the ΔΨm and antioxidant status such as superoxide dismutase (SOD) and Catalase (CAT) in pretreated H9c2 cardiomyocytes. Besides, the activity of NF-kB p65 was reduced and the p53 and Bax protein levels were inhibited in these myocardial cells subjected to DOX. These findings provide the first evidence that AMPs potently suppressed DOX-induced toxicity in cardiomyocytes through inhibition of oxidative stress and apoptosis. Thus, AMPs can be a potential therapeutic agent against DOX cardiotoxicity.

Cardiotoxicity by Anthracycline Regimen Chemotherapy Prolonged T Peak to T End Interval

Background

Myocardial necrosis may occur due to anthracycline (doxorubicin/adriamycin) chemotherapy usage. Furthermore, myocardial necrosis can affect the heterogeneity of heart conduction system and lead to repolarization abnormalities. The aim of this study was to investigate the effect of cardiotoxicity caused by anthracycline to repolarization abnormalities measured by T peak to T end (TpTe) interval.

Methods

This was a single center prospective cohort study with linear regression from October 2018 to May 2019. The subjects of the study were breast cancer patients after completing administration of chemotherapy with fluorouracil, adriamycin and cyclophosphamide (FAC) regimen (containing anthracycline) for 6 months. Myocardial necrosis was assessed by high sensitive (hs)-troponin I, and the heterogeneity of repolarization was measured by TpTe interval.

Results

This study involved 25 breast cancer patients after chemotherapy in the 6-month FAC regimen. The mean age is 46 ± 7 years, and the cumulative dose of anthracycline is 591 ± 52 mg/m². The mean level of hs-troponin I is 90.5 ± 44.7 ng/L and the TpTe interval is 108.2 ± 10 ms. The results of linear regression analysis showed a positive correlation between hs-troponin I and TpTe interval (r: 0.421, P: 0.036) after controlling for one confounding variable (cumulative dose of anthracycline).

Conclusions

Cardiotoxicity caused by accumulative dose of anthracycline may lead to myocardial necrosis which was shown by elevated hs-troponin I levels. This process may lead to heterogeneity conduction system that affect the repolarization phase of cardiac cycle which was shown by increased TpTe interval.

Adverse outcome pathways induced by 3,4-dimethylmethcathinone and 4-methylmethcathinone in differentiated human SH-SY5Y neuronal cells

Cathinones (β-keto amphetamines), widely abused in recreational settings, have been shown similar or even worse toxicological profile than classical amphetamines. In the present study, the cytotoxicity of two β-keto amphetamines [3,4-dimethylmethcathinone (3,4-DMMC) and 4-methylmethcathinone (4-MMC)], was evaluated in differentiated dopaminergic SH-SY5Y cells in comparison to methamphetamine (METH). MTT reduction and NR uptake assays revealed that both cathinones and METH induced cytotoxicity in a concentration- and time-dependent manner. Pre-treatment with trolox (antioxidant) partially prevented the cytotoxicity induced by all tested drugs, while N-acetyl-L-cysteine (NAC; antioxidant and glutathione precursor) and GBR 12909 (dopamine transporter inhibitor) partially prevented the cytotoxicity induced by cathinones, as evaluated by the MTT reduction assay. Unlike METH, cathinones induced oxidative stress evidenced by the increase on intracellular levels of reactive oxygen species (ROS), and also by the decrease of intracellular glutathione levels. Trolox prevented, partially but significantly, the ROS generation elicited by cathinones, while NAC inhibited it completely. All tested drugs induced mitochondrial dysfunction, since they led to mitochondrial membrane depolarization and to intracellular ATP depletion. Activation of caspase-3, indicative of apoptosis, was seen both for cathinones and METH, and confirmed by annexin V and propidium iodide positive staining. Autophagy was also activated by all drugs tested. Pre-incubation with bafilomycin A1, an inhibitor of the vacuolar H⁺-ATPase, only protected against the cytotoxicity induced by METH, which indicates dissimilar toxicological pathways for the tested drugs. In conclusion, the mitochondrial impairment and oxidative stress observed for the tested cathinones may be key factors for their neurotoxicity, but different outcome pathways seem to be involved in the adverse effects, when compared to METH.

The Main Metabolites of Fluorouracil + Adriamycin + Cyclophosphamide (FAC) Are Not Major Contributors to FAC Toxicity in H9c2 Cardiac Differentiated Cells

In the clinical practice, the combination of 5-fluorouracil (5-FU) + Adriamycin (also known as doxorubicin, DOX) + cyclophosphamide (CYA) (known as FAC) is used to treat breast cancer. The FAC therapy, however, carries some serious risks, namely potential cardiotoxic effects, although the mechanisms are still unclear. In the present study, the role of the main metabolites regarding FAC-induced cardiotoxicity was assessed at clinical relevant concentrations. Seven-day differentiated H9c2 cells were exposed for 48 h to the main metabolites of FAC, namely the metabolite of 5-FU, α-fluoro-β-alanine (FBAL, 50 or 100 μM), of DOX, doxorubicinol (DOXOL, 0.2 or 1 μM), and of CYA, acrolein (ACRO, 1 or 10 μM), as well as to their combination. The parent drugs (5-FU 50 μM, DOX 1 μM, and CYA 50 μM) were also tested isolated or in combination with the metabolites. Putative cytotoxicity was evaluated through phase contrast microscopy, Hoechst staining, membrane mitochondrial potential, and by two cytotoxicity assays: the reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and the neutral red (NR) lysosomal incorporation. The metabolite DOXOL was more toxic than FBAL and ACRO in the MTT and NR assays. When in combination, neither FBAL nor ACRO increased DOXOL-induced cytotoxicity. No nuclear condensation was observed for any of the tested combinations; however, a significant mitochondrial potential depolarization after FBAL 100 μM + DOXOL 1 μM + ACRO 10 μM or FBAL 100 μM + DOXOL 1 μM exposure was seen at 48 h. When tested alone DOX 1 μM was more cytotoxic than all the parent drugs and metabolites in both the cytotoxicity assays performed. These results demonstrated that DOXOL was the most toxic of all the metabolites tested; nonetheless, the metabolites do not seem to be the major contributors to FAC-induced cardiotoxicity in this cardiac model.