Effects of 5-fluorouracil on oxidative stress and calcium levels in the blood of patients with newly diagnosed colorectal cancer

Downregulating miRNA-199a-5p exacerbates fluorouracil-induced cardiotoxicity by activating the ATF6 signaling pathway

BACKGROUND

Fluorouracil (5-FU) might produce serious cardiac toxic reactions. miRNA-199a-5p is a miRNA primarily expressed in myocardial cells and has a protective effect on vascular endothelium. Under hypoxia stress, the expression level of miRNA-199a-5p was significantly downregulated and is closely related to cardiovascular events such as coronary heart disease, heart failure, and hypertension. We explored whether 5-FU activates the endoplasmic reticulum stress ATF6 pathway by regulating the expression of miRNA-199a-5p in cardiac toxicity.

METHODS

This project established a model of primary cardiomyocytes derived from neonatal rats and treated them with 5-FU in vitro. The expression of miRNA-199a-5p and its regulation were explored in vitro and in vivo.

RESULTS

5-FU decreases the expression of miRNA-199a-5p in cardiomyocytes, activates the endoplasmic reticulum stress ATF6 pathway, and increases the expression of GRP78 and ATF6, affecting the function of cardiomyocytes, and induces cardiac toxicity. The rescue assay further confirmed that miRNA-199a-5p supplementation can reduce the cardiotoxicity caused by 5-FU, and its protective effect on cardiomyocytes depends on the downregulation of the endoplasmic reticulum ATF6 signaling pathway.

CONCLUSIONS

5-FU can down-regulate expression of miRNA-199a-5p, then activate the endoplasmic reticulum stress ATF6 pathway, increase the expression of GRP78 and ATF6, affect the function of cardiomyocytes, and induce cardiac toxicity.

Oxidative Stress Induced by Chemotherapy: Evaluation of Glutathione and Its Related Antioxidant Enzyme Dynamics in Patients with Colorectal Cancer

One of the mechanisms of chemotherapy is to increase the oxidative stress of cancer cells, leading to their apoptosis. Glutathione (GSH) and its related antioxidant enzymes might be stimulated to cope with increased oxidative stress during chemotherapy. Here, we studied the fluctuation in oxidative stress and GSH-related antioxidant capacities before tumor resection, after tumor resection, and after resection either with or without chemotherapy in patients with colorectal cancer (CRC). This was a cross-sectional and follow-up design. We followed patients before having tumor resection (pre-resection), one month after tumor resection (post-resection), and after the first scheduled chemotherapy (post-chemo). If patients were required to receive chemotherapy after tumor resection, they were assigned to the chemotherapy group. Eligible patients were scheduled to undergo six to twelve cycles of chemotherapy at 2-week intervals and received single, double, or triple chemotherapeutic drugs as required. Those patients who did not require chemotherapy were assigned to the non-chemotherapy group. Indicators of oxidative stress and GSH-related antioxidant capacities were determined at the above three time points. We found in 48 patients of the chemotherapy group and in 43 patients of the non-chemotherapy group different fluctuations in levels of oxidative stress indicators and GSH-related antioxidant capacities starting from pre-resection, post-resection through the post-chemo period. Both groups showed significantly or slightly increased levels of advanced oxidation protein products (AOPP), GSH, and its related enzymes in tumor tissues compared to adjacent normal tissues. Patients in the chemotherapy group had significantly lower plasma levels of GSH and glutathione disulfide (GSSG), but had significantly higher plasma glutathione peroxidase and glutathione reductase activities than patients in the non-chemotherapy group post-chemo. Plasma levels of malondialdehyde and AOPP were positively or negatively associated with GSH and GSSG levels post-chemo after adjustment for age, sex, and histological grading in patients receiving chemotherapy. These significant associations were, however, not seen in patients without chemotherapy. Patients with CRC may require higher GSH demands to cope with a greater oxidative stress resulting from chemotherapy.

A systematic review of the therapeutic effects of resveratrol in combination with 5-fluorouracil during colorectal cancer treatment: with a special focus on the oxidant, apoptotic, and anti-inflammatory activities

PURPOSE

5-fluorouracil (5-FU), an effective chemotherapy drug, is commonly applied for colorectal cancer treatment. Nevertheless, its toxicity to normal tissues and the development of tumor resistance are the main obstacles to successful cancer chemotherapy and hence, its clinical application is limited. The use of resveratrol can increase 5-FU-induced cytotoxicity and mitigate the unwanted adverse effects. This study aimed to review the potential therapeutic effects of resveratrol in combination with 5-FU against colorectal cancer.

METHODS

According to the PRISMA guideline, a comprehensive systematic search was carried out for the identification of relevant literature in four electronic databases of PubMed, Web of Science, Embase, and Scopus up to May 2021 using a pre-defined set of keywords in their titles and abstracts. We screened 282 studies in accordance with our inclusion and exclusion criteria. Thirteen articles were finally included in this systematic review.

RESULTS

The in vitro findings showed that proliferation inhibition of colorectal cancer cells in the groups treated by 5-FU was remarkably higher than the untreated groups and the co-administration of resveratrol remarkably increased cytotoxicity induced by 5-FU. The in vivo results demonstrated a decrease in tumor growth of mice treated by 5-FU than the untreated group and a dramatic decrease was observed following combined treatment of resveratrol and 5-FU. It was also found that 5-FU alone and combined with resveratrol could regulate the cell cycle profile of colorectal cancer cells. Moreover, this chemotherapeutic agent induced the biochemical and histopathological changes in the cancerous cells/tissues and these alterations were synergized by resveratrol co-administration (for most of the cases), except for the inflammatory mediators.

CONCLUSION

The results obtained from this systematic review demonstrated that co-administration of resveratrol could sensitize the colorectal cancer cells to 5-FU treatment via various mechanisms, including regulation of cell cycle distribution, oxidant, apoptosis, anti-inflammatory effects.

Protective Effect of Kaempferol and Its Nanoparticles on 5-Fluorouracil-Induced Cardiotoxicity in Rats

BACKGROUND

Fluorouracil (5-FU) is the third most common chemotherapeutic agent used in the treatment of solid tumors. 5-FU-associated cardiotoxicity ranks the second causes of cardiotoxicity induced by chemotherapeutic drugs after anthracyclines. Kaempferol (KPF), a common flavonoid, possessing anti-inflammatory, antiapoptotic, antioxidative properties, and its protective effects on cardiovascular disease has been reported in various studies. The current study is aimed at appraising the effect of KPF and KPF nanoparticles (NPs) on 5-FU-induced cardiotoxicity in rats.

METHODS

Thirty Male Wistar rats were divided into five groups as follows: control, 5-FU, 5-FU+10 mg/kg vitamin C, 5-FU+ 1 mg/kg KPF, and 5-FU+ 1 mg/kg KPF-NPs. Cardiotoxicity was induced with an intraperitoneal injection of a single dose of 5-FU (100 mg/kg). The control group received normal saline, and the treatment groups received KPF and KPF-NPs with an intraperitoneal injection for 14 days. Each heart histopathological lesions were given a score of 0 to 3 in compliance with the articles for statistical analysis.

RESULTS

5-FU resulted in a significant cardiotoxicity represented by an increase in cardiac enzymes, MDA (malondialdehyde) levels, COX-2 (cyclooxygenase-2) expression, and histopathological degenerations. 5-FU treatment also decreased body weight, TAC (total antioxidant capacity) values, VEGF (vascular endothelial growth factor) expression, blood cells, and hemoglobin (Hb) levels. Treatment with KPF and KPF-NPs reduced oxidative stress, cardiac enzymes, COX-2 expression, and VEGF expression. The number of blood cells, Hb levels, and histopathological degenerations, in cardiac tissue also body weight of animals, increased, followed by treatment with KPF and KPF-NPs.

CONCLUSION

Our results demonstrated that treatment with KPF and KPF-NPs significantly improved cardiotoxicity induced by 5-FU in rats.

Multilayered Cell Sheets of Cardiac Reprogrammed Cells for the Evaluation of Drug Cytotoxicity

BACKGROUND

Various cell-culture systems have been used to evaluate drug toxicity in vitro. However, factors that affect cytotoxicity outcomes in drug toxicity evaluation systems remain elusive. In this study, we used multilayered sheets of cardiac-mimetic cells, which were reprogrammed from human fibroblasts, to investigate the effects of the layer number on drug cytotoxicity outcomes.

METHODS

Cell sheets of cardiac-mimetic cells were fabricated by reprogramming of human fibroblasts into cardiac-mimetic cells via coculture with cardiac cells and electric stimulation, as previously described. Double-layered cell sheets were prepared by stacking the cell sheets. The mono- and double-layered cell sheets were treated with 5-fluorouracil (5-FU), an anticancer drug, in vitro. Subsequently, apoptosis and lipid peroxidation were analyzed. Furthermore, effects of cardiac-mimetic cell density on cytotoxicity outcomes were evaluated by culturing cells in monolayer at various cell densities.

RESULTS

The double-layered cell sheets exhibited lower cytotoxicity in terms of apoptosis and lipid peroxidation than the mono-layered sheets at the same 5-FU dose. In addition, the double-layered cell sheets showed better preservation of mitochondrial function and plasma membrane integrity than the monolayer sheets. The lower cytotoxicity outcomes in the double-layered cell sheets may be due to the higher intercellular interactions, as the cytotoxicity of 5-FU decreased with cell density in monolayer cultures of cardiac-mimetic cells.

CONCLUSION

The layer number of cardiac-mimetic cell sheets affects drug cytotoxicity outcomes in drug toxicity tests. The in vitro cellular configuration that more closely mimics the in vivo configuration in the evaluation systems seems to exhibit lower cytotoxicity in response to drug.

Diagnostic potential of ionomic profile in the plasma of cervical cancer patients receiving neoadjuvant chemoradiotherapy

BACKGROUND AND AIM

Major and trace elements play an important role in human body, and it has been reported that ionomic distribution differ greatly in tumor patients. The aim of the present study was to investigate the effects of cisplatin-based neoadjuvant chemoradiotherapy on the ionomic profile in human plasma as a potential biomarker for the therapeutic effects of cervical cancer.

METHOD

Thirty-seven patients with cervical cancer receiving neoadjuvant chemoradiotherapy were included in this study, pretherapy and post-treatment blood samples were collected and concentrations of 24 ions were analyzed by inductively coupled plasma mass spectrometry (ICP-MS).

RESULTS

The results showed that after cisplatin chemotherapy and radiotherapy, patients' plasma Pt level significantly increased, Na, Mg, P, K, Ca, Se, Cu, Zn, Se, Sr, Ba levels significantly decreased (P < 0.01), and Al, Cu ions were significantly correlated with the treatment effect (P < 0.05). In addition, the pattern of elemental correlations changed dramatically after the neoadjuvant chemoradiotherapy.

CONCLUSION

The results indicated that the plasma ionomic profile may serve as a quick and convenient tool to reflect the therapeutic effect of cisplatin-based chemoradiotherapy in cervical cancer patients, and supplement of certain essential elements may be of great importance for the maintenance of ion homeostasis in human body and for the reduction of adverse effect of chemotherapy and radiotherapy.

Combined in silico and 19F NMR analysis of 5-fluorouracil metabolism in yeast at low ATP conditions

The cytotoxic effect of 5-fluorouracil (5-FU) on yeast cells is thought to be mainly via a misincorporation of fluoropyrimidines into both RNA and DNA, not only DNA damage via inhibition of thymidylate synthase (TYMS) by fluorodeoxyuridine monophosphate (FdUMP). However, some studies on Saccharomyces cerevisiae show a drastic decrease in ATP concentration under oxidative stress, together with a decrease in concentration of other tri- and diphosphates. This raises a question if hydrolysis of 5-fluoro-2-deoxyuridine diphosphate (FdUDP) under oxidative stress could not lead to the presence of FdUMP and the activation of so-called 'thymine-less death' route. We attempted to answer this question with in silico modeling of 5-FU metabolic pathways, based on new experimental results, where the stages of intracellular metabolism of 5-FU in Saccharomyces cerevisiae were tracked by a combination of 19F and 31P NMR spectroscopic study. We have identified 5-FU, its nucleosides and nucleotides, and subsequent di- and/or triphosphates. Additionally, another wide 19F signal, assigned to fluorinated unstructured short RNA, has been also identified in the spectra. The concentration of individual metabolites was found to vary substantially within hours, however, the initial steady-state was preserved only for an hour, until the ATP concentration dropped by a half, which was monitored independently via 31P NMR spectra. After that, the catabolic process leading from triphosphates through monophosphates and nucleosides back to 5-FU was observed. These results imply careful design and interpretation of studies in 5-FU metabolism in yeast.

Thermo-Sensitive TRP Channels: Novel Targets for Treating Chemotherapy-Induced Peripheral Pain

Abnormal Ca²⁺ channel physiology, expression levels, and hypersensitivity to heat have been implicated in several pain states following treatment with chemotherapeutic agents. As members of the Ca²⁺ permeable transient receptor potential (TRP), five of the channels (TRPV1-4 and TRPM2) are activated by different heat temperatures, and two of the channels (TRPA1 and TRPM8) are activated by cold temperature. Accumulating evidences indicates that antagonists of TRPA1 and TRPM8 may protect against cisplatin, oxaliplatin, and paclitaxel-induced mitochondrial oxidative stress, inflammation, cold allodynia, and hyperalgesia. TRPV1 was responsible from the cisplatin-induced heat hyperalgesia and mechanical allodynia in the sensory neurons. TRPA1, TRPM8, and TRPV2 protein expression levels were mostly increased in the dorsal root (DRG) and trigeminal ganglia by these treatments. There is a debate on direct or oxaliplatin-induced oxidative cold stress dependent TRPA1 and TRPV4 activation in the DRG. Involvement of molecular pathways such as cysteine groups, glutathione metabolism, anandamide, cAMP, lipopolysaccharide, proteinase-activated receptor 2, and mitogen-activated protein kinase were also indicated in the oxaliplatin and paclitaxel-induced cold allodynia. In this review, we summarized results of five temperature-regulated TRP channels (TRPA1, TRPM8, TRPV1, TRPV2, and TRPV4) as novel targets for treating chemotherapy-induced peripheral pain

Link between risk of colorectal cancer and serum vitamin E levels: A meta-analysis of case-control studies

BACKGROUND

The effect of low serum vitamin E levels on the risk of colorectal cancer (CRC) remains inconclusive. This meta-analysis aims to synthesize relevant studies to evaluate the association between serum vitamin E and the risk of CRC based on case-control studies.

METHODS

Potentially relevant studies were selected by searching PubMed, EMBASE, and China National Knowledge Infrastructure databases according to inclusion and exclusion criteria. The association between serum vitamin E levels and CRC was estimated by the weighted mean difference (WMD) and 95% confidence interval (CI) using a random-effects model. Heterogeneity was evaluated using Q test and I statistic. Subgroup analysis was conducted to explore sources of heterogeneity. Sensitivity analysis was performed to reveal stability and reliability.

RESULTS

A total of 10 papers with 11 studies, including 6431 subjects with 520 CRC patients and 5981 controls, were included in this present meta-analysis. The results indicated that compared with healthy controls, patients with CRC showed lower concentrations of serum vitamin E (WMD = -2.994 μmol/L, 95% CI = -4.395 to -1.593). Ethnicity subgroup analysis indicated that the serum vitamin E levels were lower in European (WMD = -1.82 μmol/L, 95% CI = -3.00 to -0.65), but not in Asian. Control-source subgroup analysis revealed that a significant association was observed in subgroup with hospital-based controls (WMD = -3.43 μmol/L, 95% CI = -6.27 to -0.59), but not in those with population-based controls. Sensitivity analysis suggested no significant difference in the pooled estimates, indicating stable results.

CONCLUSIONS

CRC is associated with a lower concentration of serum vitamin E. However, necessary prospective cohort studies should be conducted to assess the effect of serum vitamin E on the risk of CRC in the future.

Effect of Zinc Supplementation on Antioxidant Defenses and Oxidative Stress Markers in Patients Undergoing Chemotherapy for Colorectal Cancer: a Placebo-Controlled, Prospective Randomized Trial

The study aimed to investigate the effect of oral zinc supplementation on antioxidant defenses and oxidative stress markers during chemotherapy for colorectal cancer. Twenty-four patients who had undergone surgical resection of colorectal cancer participated in this placebo-controlled, prospective randomized study. The supplementation was started in the perioperative period, in which 10 patients received 70 mg of zinc (zinc group, n = 10) and 14 patients received placebo (placebo group, n = 14) for 16 weeks. Approximately 45 days after surgical resection of tumor, all patients received a chemotherapeutic regimen (capecitabine, capecitabine combined with oxaliplatin or 5-fluorouracil). Vitamin C, vitamin E, antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx), and lipid peroxidation markers malondialdehyde (MDA) and 8-isoprostane were determined before the first, second, third, and fourth chemotherapy cycles. Compared with the placebo group, the zinc group presented higher SOD values before the first, second, and fourth chemotherapy cycles and lower GPx values before the third cycle. There were no statistical differences between the study groups in vitamin C, vitamin E, MDA, or 8-isoprostane plasma values. Longitudinal analysis revealed decreased vitamin E concentration in the placebo group before the second and fourth cycles as compared with the initial values. Zinc supplementation during chemotherapy cycles increased SOD activity and maintained vitamin E concentrations. Although no effect of zinc supplementation on oxidative stress markers was observed, the increase in SOD activity indicates a production of stable free radicals, which may have a positive effect in cancer treatment.

New benzimidazole acridine derivative induces human colon cancer cell apoptosis in vitro via the ROS-JNK signaling pathway

AIM

To investigate the mechanisms underlying anticancer action of the benzimidazole acridine derivative N-{(1H-benzo[d]imidazol-2-yl)methyl}-2-butylacridin-9-amine(8m) against human colon cancer cells in vitro.

METHODS

Human colon cancer cell lines SW480 and HCT116 were incubated in the presence of 8m, and then the cell proliferation and apoptosis were measured. The expression of apoptotic/signaling genes and proteins was detected using RT-PCR and Western blotting. ROS generation and mitochondrial membrane depolarization were visualized with fluorescence microscopy.

RESULTS

8m dose-dependently suppressed the proliferation of SW480 and HCT116 cells with IC50 values of 6.77 and 3.33 μmol/L, respectively. 8m induced apoptosis of HCT116 cells, accompanied by down-regulation of Bcl-2, up-regulation of death receptor-5 (DR5), truncation of Bid, cleavage of PARP, and activation of caspases (including caspase-8 and caspase-9 as well as the downstream caspases-3 and caspase-7). Moreover, 8m selectively activated JNK and p38 without affecting ERK in HCT116 cells. Knockout of JNK1, but not p38, attenuated 8m-induced apoptosis. In addition, 8m induced ROS production and mitochondrial membrane depolarization in HCT116 cells. Pretreatment with the antioxidants N-acetyl cysteine or glutathione attenuated 8m-induced apoptosis and JNK activation in HCT116 cells.

CONCLUSION

The new benzimidazole acridine derivative, 8m exerts anticancer activity against human colon cancer cells in vitro by inducing both intrinsic and extrinsic apoptosis pathways via the ROS-JNK1 pathway.

Investigation of the effects of distance from sources on apoptosis, oxidative stress and cytosolic calcium accumulation via TRPV1 channels induced by mobile phones and Wi-Fi in breast cancer cells

TRPV1 is a Ca2+ permeable channel and gated by noxious heat, oxidative stress and capsaicin (CAP). Some reports have indicated that non-ionized electromagnetic radiation (EMR)-induces heat and oxidative stress effects. We aimed to investigate the effects of distance from sources on calcium signaling, cytosolic ROS production, cell viability, apoptosis, plus caspase-3 and -9 values induced by mobile phones and Wi-Fi in breast cancer cells MCF-7 human breast cancer cell lines were divided into A, B, C and D groups as control, 900, 1800 and 2450 MHz groups, respectively. Cells in Group A were used as control and were kept in cell culture conditions without EMR exposure. Groups B, C and D were exposed to the EMR frequencies at different distances (0 cm, 1 cm, 5 cm, 10 cm, 20 cm and 25 cm) for 1h before CAP stimulation. The cytosolic ROS production, Ca2+ concentrations, apoptosis, caspase-3 and caspase-9 values were higher in groups B, C and D than in A group at 0 cm, 1 cm and 5 cm distances although cell viability (MTT) values were increased by the distances. There was no statistically significant difference in the values between control, 20 and 25 cm. Wi-Fi and mobile phone EMR placed within 10 cm of the cells induced excessive oxidative responses and apoptosis via TRPV1-induced cytosolic Ca2+ accumulation in the cancer cells. Using cell phones and Wi-Fi sources which are farther away than 10 cm may provide useful protection against oxidative stress, apoptosis and overload of intracellular Ca2+. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers.

Selenium reduces mobile phone (900 MHz)-induced oxidative stress, mitochondrial function, and apoptosis in breast cancer cells

Exposure to mobile phone-induced electromagnetic radiation (EMR) may affect biological systems by increasing free oxygen radicals, apoptosis, and mitochondrial depolarization levels although selenium may modulate the values in cancer. The present study was designed to investigate the effects of 900 MHz radiation on the antioxidant redox system, apoptosis, and mitochondrial depolarization levels in MDA-MB-231 breast cancer cell line. Cultures of the cancer cells were divided into four main groups as controls, selenium, EMR, and EMR + selenium. In EMR groups, the cells were exposed to 900 MHz EMR for 1 h (SAR value of the EMR was 0.36 ± 0.02 W/kg). In selenium groups, the cells were also incubated with sodium selenite for 1 h before EMR exposure. Then, the following values were analyzed: (a) cell viability, (b) intracellular ROS production, (c) mitochondrial membrane depolarization, (d) cell apoptosis, and (e) caspase-3 and caspase-9 values. Selenium suppressed EMR-induced oxidative cell damage and cell viability (MTT) through a reduction of oxidative stress and restoring mitochondrial membrane potential. Additionally, selenium indicated anti-apoptotic effects, as demonstrated by plate reader analyses of apoptosis levels and caspase-3 and caspase-9 values. In conclusion, 900 MHz EMR appears to induce apoptosis effects through oxidative stress and mitochondrial depolarization although incubation of selenium seems to counteract the effects on apoptosis and oxidative stress.