Inhibition of ErbB2 by herceptin reduces viability and survival, induces apoptosis and oxidative stress in Calu-3 cell line

Promoting reactive oxygen species accumulation to overcome tyrosine kinase inhibitor resistance in cancer

BACKGROUND

In tumor treatment, protein tyrosine kinase inhibitors (TKIs) have been extensively utilized. However, the efficacy of TKI is significantly compromised by drug resistance. Consequently, finding an effective solution to overcome TKI resistance becomes crucial. Reactive oxygen species (ROS) are a group of highly active molecules that play important roles in targeted cancer therapy including TKI targeted therapy. In this review, we concentrate on the ROS-associated mechanisms of TKI lethality in tumors and strategies for regulating ROS to reverse TKI resistance in cancer.

MAIN BODY

Elevated ROS levels often manifest during TKI therapy in cancers, potentially causing organelle damage and cell death, which are critical to the success of TKIs in eradicating cancer cells. However, it is noteworthy that cancer cells might initiate resistance pathways to shield themselves from ROS-induced damage, leading to TKI resistance. Addressing this challenge involves blocking these resistance pathways, for instance, the NRF2-KEAP1 axis and protective autophagy, to promote ROS accumulation in cells, thereby resensitizing drug-resistant cancer cells to TKIs. Additional effective approaches inducing ROS generation within drug-resistant cells and providing exogenous ROS stimulation.

CONCLUSION

ROS play pivotal roles in the eradication of tumor cells by TKI. Harnessing the accumulation of ROS to overcome TKI resistance is an effective and widely applicable approach.

ADPN Regulates Oxidative Stress-Induced Follicular Atresia in Geese by Modulating Granulosa Cell Apoptosis and Autophagy

Geese are susceptible to oxidative stress during reproduction, which can lead to follicular atresia and impact egg production. Follicular atresia is directly triggered by the apoptosis and autophagy of granulosa cells (GCs). Adiponectin (ADPN), which is secreted by adipose tissue, has good antioxidant and anti-apoptotic capacity, but its role in regulating the apoptosis of GCs in geese is unclear. To investigate this, this study examined the levels of oxidative stress, apoptosis, and autophagy in follicular tissues and GCs using RT-qPCR, Western blotting, immunofluorescence, flow cytometry, transcriptomics and other methods. Atretic follicles exhibited high levels of oxidative stress and apoptosis, and autophagic flux was obstructed. Stimulating GCs with H2O2 produced results similar to those of atretic follicles. The effects of ADPN overexpression and knockdown on oxidative stress, apoptosis and autophagy in GCs were investigated. ADPN was found to modulate autophagy and reduced oxidative stress and apoptosis in GCs, in addition to protecting them from H2O2-induced damage. These results may provide a reasonable reference for improving egg-laying performance of geese.

Potential Role of Nrf2, HER2, and ALDH in Cancer Stem Cells: A Narrative Review

Cancer is one of the main causes of death among humans, second only to cardiovascular diseases. In recent years, numerous studies have been conducted on the pathophysiology of cancer, and it has been established that this disease is developed by a group of stem cells known as cancer stem cells (CSCs). Thus, cancer is considered a stem cell disease; however, there is no comprehensive consensus about the characteristics of these cells. Several different signaling pathways including Notch, Hedgehog, transforming growth factor-β (TGF-β), and WNT/β-catenin pathways cause the self-renewal of CSCs. CSCs change their metabolic pathways in order to access easy energy. Therefore, one of the key objectives of researchers in cancer treatment is to destroy CSCs. Nuclear factor erythroid 2-related factor 2 (Nrf2) plays an essential role in the protection of CSCs from reactive oxygen species (ROS) and chemotherapeutic agents by regulating antioxidants and detoxification enzymes. Human epidermal growth factor receptor 2 (HER2) is a member of the tyrosine kinase receptor family, which contributes to the protection of cancer cells against treatment and implicated in the invasion, epithelial-mesenchymal transition (EMT), and tumorigenesis. Aldehyde dehydrogenases (ALDHs) are highly active in CSCs and protect the cells against damage caused by active aldehydes through the regulation of aldehyde metabolism. On the other hand, ALDHs promote the formation and maintenance of tumor cells and lead to drug resistance in tumors through the activation of various signaling pathways, such as the ALDH1A1/HIF-1α/VEGF axis and Wnt/β-catenin, as well as changing the intracellular pH value. Given the growing body of information in this field, in the present narrative review, we attempted to shed light on the function of Nrf2, HER2, and ALDH in CSCs.

Effects of H2O2 Treatment Combined With PI3K Inhibitor and MEK Inhibitor in AGS Cells: Oxidative Stress Outcomes in a Model of Gastric Cancer

Gastric cancer is worldwide the fifth and third cancer for incidence and mortality, respectively. Stomach wall is daily exposed to oxidative stress and BER system has a key role in the defense from oxidation-induced DNA damage, whilst ErbB receptors have important roles in the pathogenesis of cancer. We used AGS cells as an aggressive gastric carcinoma cell model, treated with H2O2 alone or combined with ErbB signaling pathway inhibitors, to evaluate the effects of oxidative stress in gastric cancer, focusing on the modulation of ErbB signaling pathways and their eventual cross-talk with BER system. We showed that treatment with H2O2 combined with PI3K/AKT and MEK inhibitors influenced cell morphology and resulted in a reduction of cancer cell viability. Migration ability was reduced after H2O2 treatment alone or combined with MEK inhibitor and after PI3K/AKT inhibitor alone. Western blotting analysis showed that oxidative stress stimulated EGFR pathway favoring the MAPKs activation at the expense of PI3K/AKT pathway. Gene expression analysis by RT-qPCR showed ErbB2 and OGG1 increase under oxidative stress conditions. Therefore, we suggest that in AGS cells a pro-oxidant treatment can reduce gastric cancer cell growth and migration via a different modulation of PI3K and MAPKs pathways. Moreover, the observed ErbB2 and OGG1 induction is a cellular response to protect the cells from H2O2-induced cell death. In conclusion, to tailor specific combinations of therapies and to decide which strategy to use, administration of a chemotherapy that increases intracellular ROS to toxic levels, might not only be dependent on the tumor type, but also on the molecular targeting therapy used.

Genetic Variability of Antioxidative Mechanisms and Cardiotoxicity after Adjuvant Radiotherapy in HER2-Positive Breast Cancer Patients

Background

Breast cancer treatment is associated with the occurrence of various cardiac adverse events. One of the mechanisms associated with cardiotoxicity is oxidative stress, against which cells are protected by antioxidative enzymes. Genetic variability of antioxidative enzymes can affect enzyme activity or expression, which modifies the ability of cells to defend themselves against oxidative stress and could consequently contribute to the occurrence of treatment-related cardiotoxicity. Our aim was to evaluate the association of common polymorphisms in antioxidative genes with cardiotoxicity after adjuvant radiotherapy (RT) in HER2-positive breast cancer patients.

Methods

Our retrospective study included 101 HER2-positive early breast cancer patients who received trastuzumab and adjuvant RT. We isolated DNA from buccal swabs and used competitive allele-specific PCR for genotyping of PON1 rs854560 and rs662, GSTP1 rs1138272 and rs1695, SOD2 rs4880, CAT rs1001179, and HIF1 rs1154965 polymorphisms. N-terminal pro B-type natriuretic peptide (NT-proBNP), left ventricular ejection fraction, and NYHA class were used as markers of cardiotoxicity. We used logistic regression to evaluate the association of genetic factors with markers of cardiotoxicity.

Results

Carriers of at least one polymorphic PON1 rs854560 allele were less likely to have increased NT-proBNP (OR = 0.34; 95% CI = 0.15-0.79; P = 0.012), even after adjustment for age (OR = 0.35; 95% CI = 0.15-0.83; P = 0.017). Carriers of at least one polymorphic PON1 rs662 allele were more likely to have increased NT-proBNP (OR = 4.44; 95% CI = 1.85-10.66; P = 0.001), even after adjustment for age (OR = 5.41; 95% CI = 2.12-13.78; P < 0.001). GSTP1 rs1695 was also associated with decreased NT-proBNP in the multivariable analysis (P = 0.026), while CAT rs1001179 was associated with NYHA class in the univariable (P = 0.012) and multivariable analysis (P = 0.023).

Conclusion

In our study, polymorphisms PON1 rs662 and rs854560, CAT rs1001179, and GSTP1 rs1695 were significantly associated with the occurrence of cardiac adverse events after adjuvant RT and could serve as biomarkers contributing to treatment personalization.

Mechanobiology Assays with Applications in Cardiomyocyte Biology and Cardiotoxicity

Cardiomyocytes are the motor units that drive the contraction and relaxation of the heart. Traditionally, testing of drugs for cardiotoxic effects has relied on primary cardiomyocytes from animal models and focused on short-term, electrophysiological, and arrhythmogenic effects. However, primary cardiomyocytes present challenges arising from their limited viability in culture, and tissue from animal models suffers from a mismatch in their physiology to that of human heart muscle. Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) can address these challenges. They also offer the potential to study not only electrophysiological effects but also changes in cardiomyocyte contractile and mechanical function in response to cardiotoxic drugs. With growing recognition of the long-term cardiotoxic effects of some drugs on subcellular structure and function, there is increasing interest in using hiPSC-CMs for in vitro cardiotoxicity studies. This review provides a brief overview of techniques that can be used to quantify changes in the active force that cardiomyocytes generate and variations in their inherent stiffness in response to cardiotoxic drugs. It concludes by discussing the application of these tools in understanding how cardiotoxic drugs directly impact the mechanobiology of cardiomyocytes and how cardiomyocytes sense and respond to mechanical load at the cellular level.

Strategies for the development of selenium-based anticancer drugs

Many experimental models demonstrated that inorganic and organic selenium (Se) compounds may have an anticancer activity. However, large clinical studies failed to demonstrate that Se supplementations may prevent the outcome of cancers. Moreover, there are few randomized trials in cancer patients and there is not yet any Se compound recognized as anticancer drug. There is still a need to develop new Se compounds with new strategies. For that, it may be necessary to consider that Se compounds may have a dual role, either as anti-oxidant or as pro-oxidant. Experimental studies demonstrated that it is as pro-oxidant that Se compounds have anticancer effects, even though cancer cells have a pro-oxidant status. The oxidative status differs according to the type of cancer, the stage of the disease and to other parameters. We propose to adapt the doses of the Se compounds to markers of the oxidative stress, but also to markers of angiogenesis, which is strongly related with the oxidative status. A dual role of Se on angiogenesis has also been noted, either as pro-angiogenesis or as anti-angiogenesis. The objective for the development of new Se compounds, having a great selectivity on cancer cells, could be to try to normalize these oxidative and angiogenic markers in cancer patients, with an individual adaptation of doses.

Celastrol suppresses the proliferation of lung adenocarcinoma cells by regulating microRNA-24 and microRNA-181b

Cumulative evidence has indicated that celastrol may suppress cancer growth; however, the underlying mechanism requires further investigation. In the present study, A549 cells were treated with various concentrations of celastrol. Lung cancer cell proliferation was evaluated using an MTT assay and observed under a microscope. Cell apoptosis was detected by Annexin V fluorescein isothiocyanate/propidium iodide double-labeled flow cytometry. The results demonstrated that celastrol suppressed proliferation and induced apoptosis in a dose-independent manner. Celastrol may also decrease the phosphorylation levels of signal transducer and activator of transcription 3 (STAT3) and the B cell lymphoma-2 (Bcl-2)/Bcl-2 associated C protein (Bax) ratio. As microRNA (miR-24 and miR-181b) were predicated to target STAT3, STAT3 activation was inhibited in miR-24-or miR-181b-treated A549 cells compared with the control treatment. The ratio of Bcl-2/Bax was further reduced in miR-24 or miR-181b-treated A549 cells. The results were further confirmed by detecting in another lung adenocarcinoma cell line, LTEP-a-2. In summary, the results of the present study demonstrated that celastrol treatment suppressed the proliferation and induced apoptosis by regulating the expression levels of miR-24 and miR-181b.

Pathophysiology of cardiotoxicity from target therapy and angiogenesis inhibitors

The progress in cancer therapy and the increase in number of long-term survivors reveal the issue of cardiovascular side-effects of anticancer drugs. Cardiotoxicity has become a significant problem, and the risks of adverse cardiac events induced by systemic drugs need to be seriously considered. Potential cardiovascular toxicities linked to anticancer agents include arrhythmias, myocardial ischemia and infarction, hypertension, thromboembolism, left ventricular dysfunction, and heart failure. It has been shown that several anticancer drugs seriously affect the cardiovascular system, such as ErbB2 inhibitors, vascular endothelial growth factor (VEGF) inhibitors, multitargeted kinase inhibitors, Abelson murine leukemia viral oncogene homolog inhibitors, and others. Each of these agents has a different mechanism through which it affects the cardiovascular system. ErbB2 inhibitors block the ErbB4/ErbB2 heterodimerization pathway triggered by Neuregulin-1, which is essential for cardiomyocyte survival. VEGF signaling is crucial for vascular growth, but it also has a major impact on myocardial function, and the VEGF pathway is also essential for maintenance of cardiovascular homeostasis. Drugs that inhibit the VEGF signaling pathway lead to a net reduction in capillary density and loss of contractile function. Here, we review the mechanisms and pathophysiology of the most significant cardiotoxic effects of ErbB2 inhibitors and antiangiogenic drugs. Moreover, we highlight the role of cardioncology in recognizing these toxicities, developing strategies to prevent or minimize cardiovascular toxicity, and reducing long-term cardiotoxic effects.

Anthracyclines/trastuzumab: new aspects of cardiotoxicity and molecular mechanisms

Anticancer drugs continue to cause significant reductions in left ventricular ejection fraction resulting in congestive heart failure. The best-known cardiotoxic agents are anthracyclines (ANTHs) such as doxorubicin (DOX). For several decades cardiotoxicity was almost exclusively associated with ANTHs, for which cumulative dose-related cardiac damage was the use-limiting step. Human epidermal growth factor (EGF) receptor 2 (HER2; ErbB2) has been identified as an important target for breast cancer. Trastuzumab (TRZ), a humanized anti-HER2 monoclonal antibody, is currently recommended as first-line treatment for patients with metastatic HER2(+) tumors. The use of TRZ may be limited by the development of drug intolerance, such as cardiac dysfunction. Cardiotoxicity has been attributed to free-iron-based, radical-induced oxidative stress. Many approaches have been promoted to minimize these serious side effects, but they are still clinically problematic. A new approach to personalized medicine for cancer that involves molecular screening for clinically relevant genomic alterations and genotype-targeted treatments is emerging.

Progressive loss of anti-HER2 CD4+ T-helper type 1 response in breast tumorigenesis and the potential for immune restoration

Genomic profiling has identified several molecular oncodrivers in breast tumorigenesis. A thorough understanding of endogenous immune responses to these oncodrivers may provide insights into immune interventions for breast cancer (BC). We investigated systemic anti-HER2/neu CD4⁺ T-helper type-1 (Th1) responses in HER2-driven breast tumorigenesis. A highly significant stepwise Th1 response loss extending from healthy donors (HD), through HER2^pos-DCIS, and ultimately to early stage HER2^pos-invasive BC patients was detected by IFNγ ELISPOT. The anti-HER2 Th1 deficit was not attributable to host-level T-cell anergy, loss of immune competence, or increase in immunosuppressive phenotypes (T_reg/MDSCs), but rather associated with a functional shift in IFNγ:IL-10-producing phenotypes. HER2^high, but not HER2^low, BC cells expressing IFNγ/TNF-α receptors were susceptible to Th1 cytokine-mediated apoptosis in vitro, which could be significantly rescued by neutralizing IFNγ and TNF-α, suggesting that abrogation of HER2-specific Th1 may reflect a mechanism of immune evasion in HER2-driven tumorigenesis. While largely unaffected by cytotoxic or HER2-targeted (trastuzumab) therapies, depressed Th1 responses in HER2^pos-BC patients were significantly restored following HER2-pulsed dendritic cell (DC) vaccinations, suggesting that this Th1 defect is not "fixed" and can be corrected by immunologic interventions. Importantly, preserved anti-HER2 Th1 responses were associated with pathologic complete response to neoadjuvant trastuzumab/chemotherapy, while depressed responses were observed in patients incurring locoregional/systemic recurrence following trastuzumab/chemotherapy. Monitoring anti-HER2 Th1 reactivity following HER2-directed therapies may identify vulnerable subgroups at risk of clinicopathologic failure. In such patients, combinations of existing HER2-targeted therapies with strategies to boost anti-HER2 CD4⁺ Th1 immunity may decrease the risk of recurrence and thus warrant further investigation.

Effect of celastrol on growth inhibition of prostate cancer cells through the regulation of hERG channel in vitro

Objective. To explore the antiprostate cancer effects of Celastrol on prostate cancer cells' proliferation, apoptosis, and cell cycle distribution, as well as the correlation to the regulation of hERG. Methods. DU145 cells were treated with various concentrations of Celastrol (0.25–16.0 μmol/L) for 0–72 hours. MTT assay was used to evaluate the inhibition effect of Celastrol on the growth of DU145 cells. Cell apoptosis was detected through both Annexin-V FITC/PI double-labeled cytometry and Hoechst 33258. Cell cycle regulation was examined by a propidium iodide method. Western blot and RT-PCR technologies were applied to assess the expression level of hERG in DU145 cells. Results. Celastrol presented striking growth inhibition and apoptosis induction potency on DU145 cells in vitro in a time- and dose-dependent manner. The IC₅₀ value of Celastrol for 24 hours was 2.349 ± 0.213 μmol/L. Moreover, Celastrol induced DU145 cell apoptosis in a cell cycle-dependent manner, which means Celastrol could arrest DU145 cells in G₀/G₁ phase; accordingly, cells in S phase decreased gradually and no obvious changes were found in G₂/M phase cells. Through transmission electron microscope, apoptotic bodies containing nuclear fragments were found in Celastrol-treated DU145 cells. Overexpression of hERG channel was found in DU145 cells, while Celastrol could downregulate it at both protein and mRNA level in a dose-dependent manner (P < 0.01). Conclusions. Celastrol exhibits its antiprostate cancer effects partially through the downregulation of the expression level of hERG channel in DU145 cells, suggesting that Celastrol may be a potential agent against prostate cancer with a mechanism of blocking the hERG channel.

Em08red, a dual functional antiproliferative emodin analogue, is a downregulator of ErbB2 expression and inducer of intracellular oxidative stress

Expression of ErbB2 protein is inversely correlated with the prognosis in cancer patients. Consequently, strategies targeting ErbB2 remain an attractive option in treating several types of malignancies, including oral cancer. In addition, many studies have shown that emodin and emodin derivatives are able to inhibit growth of ErbB2-overexpressing tumor cells. In this study, a series of computer modeling-generated emodin analogues were synthesized and tested for their antiproliferative activity against oral cancer cell lines overexpressing ErbB2. Among these analogues, em08red (1,8-dihydroxy-9(10H)-anthracenone) demonstrated potent antiproliferative activity against all three tested ErbB2-overexpressing cell lines, ie, FaDu, HSC3, and OECM1. Treatment with em08red significantly downregulated activation of ErbB2 as well as the ErbB2 protein expression level in the tested cell lines and induced G2 arrest. Antiapoptosis protein (Bcl-xl and Bcl-2) expression levels were also downregulated, and active caspase-3 and caspase-9 was detected in cells after treatment with em08red. Moreover, treatment with em08red stimulated production of cytotoxic reactive oxygen species in treated cells, and this could be partially reversed by pretreatment with N-acetylcysteine. Overall, we demonstrated inhibition of ErbB2 function and induction of reactive oxygen species in tumor cells by em08red, which prevented proliferation of tumor cells and induced apoptotic cell death.

Should we be more cautious about replacement of vitamin B12 in patients with cancer receiving cytotoxic chemotherapy?

Vitamin B12 (Cbl) deficiency may cause hematologic and neurologic dysfunction. Replacement therapy is effective in correcting hematologic abnormalities and improving neurologic symptoms. Cbl is known to have antioxidant activity. This antioxidant activity may antagonize the effects of chemotherapeutics (i.e. genotoxic effects of paclitaxel) on tumor DNA. We claim that Cbl replacement should be done more cautiously in patients receiving cytotoxic chemotherapy.

The role of antioxidants in the era of cardio‑oncology

Although most chemotherapeutic drugs have the potential to exert cardiotoxicity, these drugs have been chosen for use in cancer treatment because survival and curability benefits outweigh the risk of these complications. Anthracyclines, for example, are a powerful class of chemotherapeutic agents; however, their use is restricted by dose-related cardiotoxicity. Experimental evidence strongly supports the role of reactive oxygen species in this process, suggesting that antioxidants may be effective in protecting the heart from toxicity. Clinical use of antioxidants to protect the heart during anthracycline chemotherapy has been controversial due to the potential for reduced cytotoxic efficacy toward cancer cells. Results from randomized clinical trials addressing whether antioxidants either reduce the incidence of clinical heart failure among patients undergoing anthracycline-based chemotherapy or reduce the response rates to anthracycline-based chemotherapy have been unclear. While anthracyclines are by far the most well-studied antitumor agents with cardiotoxic properties, evidence now shows that reactive oxygen species may play roles in cardiotoxicity induced by other chemotherapeutic agents such as cyclophosphamide, cisplatin, 5-fluorouracil, and trastuzumab. Thus, in the new era of combination therapy and long-term survival of cancer patients, the use of antioxidants to support cancer therapy should be revisited.

Carbonyl stress in aging process: role of vitamins and phytochemicals as redox regulators

There is a growing scientific agreement that the cellular redox regulators such as antioxidants, particularly the natural polyphenolic forms, may help lower the incidence of some pathologies, including metabolic diseases like diabetes and diabesity, cardiovascular and neurodegenerative abnormalities, and certain cancers or even have anti-aging properties. The recent researches indicate that the degree of metabolic modulation and adaptation response of cells to reductants as well as oxidants establish their survival and homeostasis, which is linked with very critical balance in imbalances in cellular redox capacity and signaling, and that might be an answer the questions why some antioxidants or phytochemicals potentially could do more harm than good, or why some proteins lose their function by increase interactions with glyco- and lipo-oxidation mediates in the cells (carbonyl stress). Nonetheless, pursue of healthy aging has led the use of antioxidants as a means to disrupt age-associated physiological dysfunctions, dysregulated metabolic processes or prevention of many age-related diseases. Although it is still early to define their exact clinical benefits for treating age-related disease, a diet rich in polyphenolic or other forms of antioxidants does seem to offer hope in delaying the onset of age-related disorders. It is now clear that any deficiency in antioxidant vitamins, inadequate enzymatic antioxidant defenses can distinctive for many age-related disease, and protein carbonylation can used as an indicator of oxidative stress associated diseases and aging status. This review examines antioxidant compounds and plant polyphenols as redox regulators in health, disease and aging processes with hope that a better understanding of the many mechanisms involved with these distinct compounds, which may lead to better health and novel treatment approaches for age-related diseases.

Suppression of FUT1 attenuates cell proliferation in the HER2-overexpressing cancer cell line NCI-N87

Lewis Y (LeY) antigen is an oligosaccharide that is highly expressed at the cell surface in various human cancers. Increased LeY expression activates epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2) and promotes cell proliferation in EGFR-overexpressing cells. However, the effect of downregulation of LeY expression on cell proliferation in HER2-overexpressing cells remains unknown. FUT1 encodes α1,2-fucosyltransferase, a key enzyme for LeY synthesis. We knocked down FUT1 by short interfering RNA (siRNA) in four HER2-overexpressing human cancer cell lines, including NCI-N87, MKN7, SKBr3 and BT474. We investigated whether downregulation of LeY and alteration in the glycosylation status of these cells affect cell proliferation and HER2 activation. Knocking down FUT1 expression markedly inhibited proliferation of NCI-N87, which highly expressed EGFR and was sensitive to EGFR deprivation. Furthermore, FUT1 siRNA downregulated the total amount of HER2 protein, phosphorylation of HER2 and EGFR, and phosphorylation of extracellular signal-regulated kinase (ERK) in this cell line. Moreover, the marked downregulation of phosphorylation of HER2 and ERK was observed following short-time EGF-stimulation. These effects were not observed in the other three cell lines. Our results suggest that knockdown of FUT1 downregulates HER2 signaling via EGFR downregulation. FUT1 may serve as a new molecular target for HER2-overexpressing human cancers with activated EGFR signaling.