Troxerutin with copper generates oxidative stress in cancer cells: Its possible chemotherapeutic mechanism against hepatocellular carcinoma

The detoxification of cadmium in Japanese quail by pomegranate peel powder

Environmental pollution and exposure to toxic metals such as cadmium (Cd) can cause severe and chronic diseases and have significant side effects on vital organs. The present study aimed to evaluate the effect of pomegranate peel on biochemical factors and lipid peroxidation in intoxication by Cd in Japanese quail. Two hundred seventy quails in different groups were fed diets containing Cd and pomegranate peel from 6 to 35 days old. Then, serum biochemical parameters were assessed, including liver enzymes, urea, and thiobarbituric acid. In the quails, Cd significantly increased MDA, urea, and AST (P < 0.05). Adding pomegranate peel at 1.5 and 2% levels decreased these parameters significantly (P < 0.05). In conclusion, dietary enrichment using pomegranate peel reduced the adverse effects of Cd by improving lipid peroxidation, aspartate aminotransferase (AST), and urea in Japanese quail.

The creation of selenium nanoparticles decorated with troxerutin and their ability to adapt to the tumour microenvironment have therapeutic implications for triple-negative breast cancer

The unique use of selenium–troxerutin nanoconjugates as an effective management therapy for treating TNBC.

Cuproptosis-Related Signature Predicts the Prognosis, Tumor Microenvironment, and Drug Sensitivity of Hepatocellular Carcinoma

Background

Copper (Cu) metabolism is strongly associated with liver disease. Cuproptosis is a novel format of cell death, and cuproptosis-related genes (CRGs) were identified. However, the role of CRGs in Hepatocellular Carcinoma (HCC) remains unknown.

Method

The mRNA transcriptome profiling data, somatic mutation data, and copy number gene level data of The Cancer Genome Atlas-Liver Hepatocellular Carcinoma project (TCGA-LIHC) were downloaded for subsequent analysis. Molecular characterization analysis of CRGs, including differential gene expression analysis, mutation analysis, copy number variation (CNV) analysis, Kaplan-Meier analysis, and immune regulator prioritization analysis, was implemented. The nonnegative matrix factorization (NMF) approach was used to identify the CRG-related molecular subtypes. Principal component analysis was adopted to verify the robustness and reliability of the molecular subtype. The least absolute shrinkage and selection operator regression analysis was performed to construct the prognostic signature based on differentially expressed genes between molecular subtypes. The survival characteristics of the molecular subtype and the signature were analyzed. The Gene Set Variation Analysis was performed for functional annotation. The immune landscape analysis, including immune checkpoint gene analysis, single sample gene set enrichment analysis, tumor immune dysfunction and exclusion (TIDE) analysis, immune infiltration cell, and tumor mutation burden analysis (TMB), was conducted. The ability of the signature to predict conventional anti-HCC agent responses was evaluated. The signature was validated in the LIRI-JP cohort and the IMvigor210 cohort.

Result

A total of 13 CRGs are differentially expressed between the tumor and normal samples, while the mutation of CRGs in HCC is infrequent. The expression of CRGs is associated with the CNV level. Fourteen CRGs are associated with the prognosis of HCC. Two clusters were identified and HCC patients were divided into 2 groups with a cutoff risk score value of 1.570. HCC patients in the C1 cluster and high-risk have a worse prognosis. The area under the receiver operating characteristic curve for predicting 1-, 2-, and 3-year overall survival is 0.775, 0.768, and 0.757 in the TCGA-LIHC cohort, and 0.811, 0.741, and 0.775 in the LIRI-JP cohort. Multivariate Cox regression analysis indicates that the signature is an independent prognostic factor. Pathways involved in metabolism and gene stability and immune infiltration cells are significantly enriched. Immune checkpoint genes are highly expressed in the C1 cluster. TMB is positively correlated with the risk score. HCC patients in the high-risk group are more likely to benefit from conventional anti-HCC agents and immune checkpoint inhibitor therapies.

Conclusion

The molecular characterization of CRGs in HCC is presented in this study, and a successful prognostic signature for HCC based on the cuproptosis-related molecular subtype was constructed.

Enhanced antitumor effect of L-buthionine sulfoximine or ionizing radiation by copper complexes with 2,2´-biquinoline and sulfonamides on A549 2D and 3D lung cancer cell models

Two ternary copper(II) complexes with 2,2'-biquinoline (BQ) and with sulfonamides: sulfamethazine (SMT) or sulfaquinoxaline (SDQ) whose formulae are Cu(SMT)(BQ)Cl and Cu(SDQ)(BQ)Cl·CH₃OH, in what follows SMTCu and SDQCu, respectively, induced oxidative stress by increasing ROS level from 1.0 μM and the reduction potential of the couple GSSG/GSH². The co-treatment with L-buthionine sulfoximine (BSO), which inhibits the production of GSH, enhanced the effect of copper complexes on tumor cell viability and on oxidative damage. Both complexes generated DNA strand breaks given by-at least partially-the oxidation of pyrimidine bases, which caused the arrest of the cell cycle in the G2/M phase. These phenomena triggered processes of apoptosis proven by activation of caspase 3 and externalization of phosphatidylserine and loss of cell integrity from 1.0 μM. The combination with BSO induced a marked increase in the apoptotic population. On the other hand, an improved cell proliferation effect was observed when combining SDQCu with a radiation dose of 2 Gy from 1.0 μM or with 6 Gy from 1.5 μM. Finally, studies in multicellular spheroids demonstrated that even though copper(II) complexes did not inhibit cell invasion in collagen gels up to 48 h of treatment at the higher concentrations, multicellular resistance outperformed several drugs currently used in cancer treatment. Overall, our results reveal an antitumor effect of both complexes in monolayer and multicellular spheroids and an improvement with the addition of BSO. However, only SDQCu was the best adjuvant of ionizing radiation treatment.

Biological and Therapeutic Effects of Troxerutin: Molecular Signaling Pathways Come into View

Flavonoids consist a wide range of naturally occurring compounds which are exclusively found in different fruits and vegetables. These medicinal herbs have a number of favourable biological and therapeutic activities such as antioxidant, neuroprotective, renoprotective, anti-inflammatory, anti-diabetic and anti-tumor. Troxerutin, also known as vitamin P4, is a naturally occurring flavonoid which is isolated from tea, coffee and cereal grains as well as vegetables. It has a variety of valuable pharmacological and therapeutic activities including antioxidant, anti-inflammatory, anti-diabetic and anti-tumor. These pharmacological impacts have been demonstrated in in vitro and in vivo studies. Also, clinical trials have revealed the efficacy of troxerutin for management of phlebocholosis and hemorrhoidal diseases. In the present review, we focus on the therapeutic effects and biological activities of troxerutin as well as its molecular signaling pathways.

The Protective Roles and Molecular Mechanisms of Troxerutin (Vitamin P4) for the Treatment of Chronic Diseases: A Mechanistic Review

Troxerutin (TRX), a semi-synthetic bioflavonoid derived from rutin, has been reported to exert several pharmacological effects including antioxidant, anti-inflammatory, antihyperlipidemic, and nephroprotective. However, the related molecular details and its mechanisms remain poorly understood. In the present review, we presented evidences from the diversity in vitro and in vivo studies on the therapeutic potential of TRX against neurodegenerative, diabetes, cancer and cardiovascular diseases with the purpose to find molecular pathways related to the treatment efficacy. TRX has a beneficial role in many diseases through multiple mechanisms including, increasing antioxidant enzymes and reducing oxidative damage, decreasing in proapoptotic proteins (APAF-1, BAX, caspases-9 and-3) and increasing the antiapoptotic BCL-2, increasing the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and downregulating the nuclear factor κB (NFκ). TRX also reduces acetylcholinesterase activity and upregulates phosphoinositide 3- kinase/Akt signaling pathway in Alzheimer's disease models. Natural products such as TRX may develop numerous and intracellular pathways at several steps in the treatment of many diseases. Molecular mechanisms of action are revealing novel, possible combinational beneficial approaches to treat multiple pathological conditions.

Anti-inflammatory effects of troxerutin are mediated through elastase inhibition

CONTEXT

Obesity is a chronic low-grade inflammatory state associated with immune cell infiltration into the adipose tissue (AT). We hypothesize that the anti-obesity and anti-inflammatory effects of troxerutin (TX) are mediated through inhibition of elastase.

OBJECTIVE

To determine the inhibitory effect of TX on elastase in vitro and in tumor necrosis factor alpha (TNFα) induced 3T3-L1 adipocytes and the molecular interaction of TX with human neutrophil elastase (HNE).

MATERIALS AND METHODS

Differentiated 3T3-L1 adipocytes were pretreated with TX, elastatinal (ELAS) or sodium salicylate (SAL) before exposure to TNFα. Lipid accumulation, reactive oxygen species (ROS) generation and oxidant-antioxidant balance were examined. The mRNA and protein expression of TNFα, interleukin-6, monocyte chemoattractant protein-1, adiponectin, leptin, resistin, chemerin, and elastase were analyzed. Elastase inhibition by TX and ELAS in a cell free system and docking studies for HNE with TX and ELAS were performed.

RESULTS

TX, ELAS or SAL pretreatment had lowered lipid droplets formation and TG content. TX suppressed ROS generation, oxidative stress and improved antioxidant status. The expression of inflammatory cytokines and elastase was downregulated while that of adiponectin was upregulated by TX. The concentration required to produce 50% inhibition in vitro (IC₅₀) was 11.5 μM for TX and 16.9 μM for ELAS. TX showed hydrogen bonding and hydrophobic interactions with elastase.

DISCUSSION

TNFα induces inflammation of 3T3-L1 cells through elastase activation. TX inhibits elastase activity, downregulates expression and binds with elastase.

CONCLUSION

The antioxidant and anti-inflammatory activities of TX in AT could be of relevance in the management of obesity.

Anticancer and cytotoxic effects of troxerutin on HeLa cell line: an in-vitro model of cervical cancer

Cervical cancer is one of the grave uterine tumors which leads to death in women worldwide. Troxerutin (TRX) as a bioflavonoid compound has many pharmacological effects such as anti-neoplastic, radioprotective, and anti-cancer. The present study was designed to examine the cytotoxic effect of TRX on human HeLa tumor cells. Human HeLa cells were cultured and treated with different doses of TRX (20-640 mg/ml) to evaluate the effective half-maximal inhibitory concentration (IC₅₀) after 24 h. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) test was used for cell proliferation assay. Also, the Bax, Bcl-2, cleaved caspase-3, and tumor necrosis factor-α (TNF-α) protein expression levels were detected with immunoblotting analysis. The malondialdehyde (MDA) concentration, glutathione peroxidase (GPx) and superoxide dismutase (SOD) activity levels were measured via their commercial kits. Data were analyzed using one-way ANOVA. The result showed that TRX at 320 mg/ml concentration (IC₅₀) has a growth inhibitory effect against HeLa cells at 24 h treatment (P ˂ 0.01). Moreover, it increased the MDA concentration and also decreased the GPx and SOD activity levels at 320 mg/ml concentration versus control (P < 0.001). Also, TRX significantly up-regulated the Bax, cleaved caspase-3 and TNF-α proteins expression levels (P  <  0.01) and down-regulated the Bcl-2 protein expression in HeLa tumor cells at 320 mg/ml concentration compared to control (P < 0.05). Our study showed that 24 h of treatment with TRX (320 mg/ml) has apoptotic and growth inhibitory effects against HeLa cells. It can induce inflammation (at least via up-regulating the TNF-α protein expression) and oxidative stress in human HeLa cells.

Cucurbita ficifolia Fruit Extract Induces Tp53/Caspase-Mediated Apoptosis in MCF-7 Breast Cancer Cells

The second most biggest cancer worldwide is breast cancer. There is an increasing need for safer, effective, and affordable drug candidates from natural sources to treat breast cancer. In the present investigation, the anticancer effect of Cucurbita ficifolia Bouché (C. ficifolia) fruit extract was tested on the human breast cancer cells such as MCF-7. The cells were exposed with different doses of C. ficifolia, for the assessment of IC₅₀ concentrations on the MCF-7 cell lines for 24 hs. The effect of C. ficifolia fruit extract on morphological and apoptotic changes were evaluated by specific fluorescence staining techniques and real-time PCR in a time-dependent manner for 24 hs and 48 hs. The IC₅₀ value for C. ficifolia fruit extract was found to be 90 μg/mL. Morphological alteration and apoptotic distinctiveness aspect like chromatin condensation and nuclear fragmentation were noticed in C. ficifolia extract exposed breast cancer cells. Further, we observed that C. ficifolia extract-induced programmed cell death in the MCF-7 cells were mediated with the elevated expression of the tumor suppressor gene such as p53 and apoptotic markers such as caspase-8, caspase-9, caspase-3, fatty acid synthase (FAS), Fas-associated protein with death domain (FADD), Bcl-2 homologous antagonist/killer (BAK), and Bcl-2-associated X protein (BAX). These observations established that C. ficifolia significantly concealed the cell division and provoked p53/caspase-mediated programmed cell death. Further, we noticed that this cell death in MCF-7 cells is concentration and time dependent. As evaluated through the comet assay, C. ficifolia induced DNA damage; further upon increasing the duration of the treatment, the DNA damage was higher than before. Thus, our study concludes that C. ficifolia could serve as an effective anticancer agent through vital gene modulation.

Comparative Analysis of Age-Related Changes in Lacrimal Glands and Meibomian Glands of a C57BL/6 Male Mouse Model

It is not known how biological changes in the lacrimal (LGs) and meibomian (MGs) glands contribute to dry eye disease (DED) in a time-dependent manner. In this study, we investigated time-sequenced changes in the inflammation, oxidative stress, and senescence of stem cells in both glands of an aging-related DED mouse model. Eight-week (8W)-, one-year (1Y)-, and two-year (2Y)-old C57BL/6 male mice were used. MG areas of the upper and lower eyelids were analyzed by transillumination meibography imaging. The number of CD45⁺, 8-OHdG⁺, Ki-67⁺, and BrdU⁺ cells was compared in both glands. Increased corneal staining and decreased tear secretion were observed in aged mice. The MG dropout area increased with aging, and the age-adjusted MG area in lower lids was negatively correlated with the National Eye Institute (NEI) score. Increased CD4⁺ interferon (IFN)-γ⁺ cells in LGs were found in both aged mice. An increase in 8-OHdG⁺ cells in both glands was evident in 2Y-old mice. Reduced Ki-67⁺ cells, but no change in CD45⁺ cells, was observed in the MGs of 1Y-old mice. Increased BrdU⁺ cells were observed in the LGs of aged mice. This suggests that age-dependent DED in C57BL/6 mice is related to inflammation of the LGs, the development of MG atrophy, and oxidative stress in both glands.

Redox cycling of copper by coumarin-di(2-picolyl)amine hybrid molecule leads to ROS-mediated modulation of redox scavengers, DNA damage and cell death in diethylnitrosamine induced hepatocellular carcinoma

Targeted therapy is a new strategy for cancer treatment that targets chemical entities specific to cancer cells than normal ones. One of the features associated with malignancy is the elevated copper which plays an integral role in angiogenesis. Work is in progress in our lab to identify new copper chelators to target elevated copper under targeted therapy for the killing of cancer cells. Recently, a coumarin-based copper chelator, di(2-picolyl)amine-3(bromoacetyl)coumarin hybrid molecule (ligand-L) has been synthesized by us, and also studied its copper-dependent macromolecular damage response in copper overloaded lymphocytes. The present study investigates the anticancer activity of ligand-L and its mode of action in rat model of diethylnitrosamine (DEN) induced hepatocellular carcinoma. It has been found that liver tissue has a marked increase in copper levels in DEN induced hepatocellular carcinoma. Ex vivo results showed that ligand-L inhibited cell viability, induced reactive oxygen species (ROS) generation, DNA damage, loss of mitochondrial membrane potential and caspase-3 activation in isolated hepatocellular carcinoma cells (HCC). All these effects induced by ligand-L were abrogated by neocuproine and N-acetylcysteine (ROS scavenger). Further, ligand-L treatment of animals bearing hepatocellular carcinoma results in an increment in the cellular redox scavengers, lipid peroxidation and DNA breakage in malignant hepatocytes. In vivo studies using ligand-L also showed that ligand-L possesses anticancer properties as evidenced by improvement in liver marker enzymes and liver surface morphology, and reduced alpha-fetoprotein in the treated group compared to untreated cancer-induced group. Overall, this study suggests that copper-ligand-L interaction leads to ROS generation which caused DNA damage and apoptosis in malignant cells. This study provides enough support to establish ligand-L as a clinically relevant lead molecule for the treatment of different malignancies.

Curcuma longa and Trigonella foenum graecum-enriched nutrient mixture from germinated Macrotyloma uniflorum and Vigna radiate ameliorate nonalcoholic fatty liver diseases in rats

The prevalence of nonalcoholic fatty liver is increasing due to modern lifestyle. Germinated and dehulled Macrotyloma uniflorum and Vigna radiate were shown to have enhanced nutrients. Curcuma longa and Trigonella foenum graecum were proven hepatoprotective.The supplementation of the nutrient herbal mixture to the MCD diet-induced steatosis shows reduced hepatic fat accumulation and lipid profile, and liver injury markers in serum also reserved in normal. Increased serum albumin in the treatment group indicates that the liver function is enhanced than that of steatosis. The supplementation of the herbal mixture has preserved the hepatic antioxidant. Zymographic analysis of matrix metalloproteinase, western blot determination of α-SMA, and histological evolution (H&E, Sirius red) depicted reduced fibrosis and reveled management of hepatic stellate cells in quiescent form. The present study concludes that the herbal mixture has reduced hepatocyte fat accumulation in steatotic animals, and curtailed the oxidative stress, further it prevents the progression of steatohepatitis. PRACTICAL APPLICATIONS: Fatty liver diseases can be treated by modulating the diet composition such as consuming food rich in the nutrient herbal mixture. In this study, the nutrient mixture was made with dynamic food processing techniques such as germination, dehulling, and milling to augment the nutritional contents. Besides, Macrotyloma uniflorum, Vigna radiate, Curcuma longa, and Trigonella foenum graecum were used to improve the medicinal value and antioxidant. This formulation could target the various stages of NAFLD. This study revealed that the nutrient herbal mixture reduces the steatosis of the liver and curtailed the progression of steatohepatitis from hepatic steatosis. Since the edible foodstuff was used to make the nutrient mixture, it has excellent clinical application.

Nutrient mixture from germinated legumes: Enhanced medicinal value with herbs-attenuated liver cirrhosis

Among various food processing strategies, germination and dehulling enhance the nutritional content of the food, and the addition of herbs to this could improve the medicinal value. The milled powders of germinated Macrotyloma uniflorum (horse gram) and Vigna radiata (green gram) were used to make the nutrient mixture. Further, Curcuma longa (turmeric) and Trigonella foenum graecum (fenugreek) were used to improve its medicinal value. The prepared nutrient mixture has high nutritional value, antioxidant potential, and reduced antinutrient factors. Supplementation of nutrient mixture reduced oxidative stress-mediated hepatocyte injury on the CCl₄ -induced liver cirrhosis model. Further, histological examination (H&E and Sirius red), matrix metalloproteinase gelatin zymography, and Western blot revealed the management of hepatic stellate cells in an inactive stage thereby reduced cirrhosis. These findings conclude that the supplementation of nutrient mixture formulation protected and effectively prevented liver cirrhosis. PRACTICAL APPLICATIONS: This study has a good impact on nutritional therapy for liver diseases. Many of the chronic liver diseases are associated with severe malnutrition and hypoalbuminemia, which further worsens the condition. This study would emphasize the nutritional therapy to treat such imbalance and enriching the medicinal value of nutrition mixture with herbs could target different pathophysiological changes and provide better defense in liver disease patients. Since this nutrient mixture is from common edible natural resources, it could reach the pharmaceutical industry's attention to the highest production and marketing.

Arsenic trioxide, a cancer chemo drug hampers fibrotic liver regeneration by interrupting oxidative stress rekindling and stellate cell rejuvenation

After withdrawal of liver toxic insult, the spontaneous regenerative potential of the liver is well reported in the literature. On the other hand, various molecules have been reported to promote as well as delay such natural regeneration. This current study investigates the involvement of arsenic trioxide (ATO) medication at chemotherapeutic dose on the spontaneous regeneration of the CCl₄ induced fibrotic liver. Liver injury markers, such as albumin and SGOT, SGPT, and ALP activities, in serum indicated that ATO supplementation during liver regeneration hampers the rejuvenation process. The hepatic architecture as well as the degree of fibrosis by hematoxylin and eosin and Sirius red staining confirms the above findings. The reduced hepatic antioxidant system and elevated oxidative stress markers, such as lipid peroxidation and 8-hydroxy deoxy-guanosine-positive hepatocytes in ATO supplied rats, display the persistence of oxidative stress when compared with healthy controls and the normal regeneration model. Immuno-histochemical localization of Ki-67 indicates that mitotically active hepatocytes were fewer in the ATO given rats when compared with normal regeneration rats. Further delay in hepatic fibrinolysis was monitored by matrix metalloproteinase zymography assay in the ATO-given animals. Poly(ADP-ribose) polymerase 1 expression demonstrates elevated hepatocyte apoptosis with ATO. Furthermore, increased α-smooth muscle actin indicates that the stellate cells are in an activated state in ATO supplemented fibrotic animals. In conclusion, it's observed that ATO supplementation to the fibrotic liver delays oxidative stress revitalization and maintains stellate cells in the active form, thereby delaying liver regeneration, and the health status of the liver must be taken into account before administering drugs like ATO.

Combining an in silico approach with an animal experiment to investigate the protective effect of troxerutin for treating acute lung injury

Background

Troxerutin (TRX), a naturally occurring flavonoid in various fruits, has been reported to exhibit numerous pharmacological and biological activities in vitro and in vivo. However, the molecular mechanisms underlying TRX as a treatment for disease are poorly understood.

Methods

Using pharmacophore mapping and inverse docking, a set of potential TRX target proteins that have been associated with multiple forms of diseases was obtained. Bioinformatic analyses were performed using the Enrichr and STRING servers to analyse the related biological processes and protein-protein networks. Furthermore, we investigated the potential protective effect of TRX against lipopolysaccharide-induced acute lung injury (ALI) using a mouse model. Morphological changes in the lungs were assessed using haematoxylin and eosin staining. Inflammatory cytokines, tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6 and IL-10 were investigated using ELISA. Activation of MAPK and NF-κB was detected using western blotting.

Results

Our network pharmacology analysis revealed the existence of multiple TRX-related chemical-target interactions and the related biological processes. We found that pretreatment with TRX protected against histological changes and obviously regulated the inflammatory cell counts and inflammatory cytokine levels in bronchoalveolar lavage fluid. Based on bioinformatic and western blot analyses, TRX may exert a protective effect against ALI by inhibiting MAPK and NF-κB signalling.

Conclusions

TRX can ameliorate pulmonary injury by inhibiting the MAPK and NF-κB signalling pathways and has a potential protective effect against ALI. This study may be helpful for understanding the mechanisms underlying TRX action and for discovering new drugs from plants for the treatment of ALI.

Electronic supplementary material

The online version of this article (10.1186/s12906-019-2515-7) contains supplementary material, which is available to authorized users.

6-Methoxyquinoline complexes as lung carcinoma agents: induction of oxidative damage on A549 monolayer and multicellular spheroid model

The aim of this work was to study the antitumor effects and the mechanisms of toxic action of a series of 6-methoxyquinoline (6MQ) complexes in vitro. The Cu(II) and Zn(II) complexes (Cu6MQ and Zn6MQ) are formulated as M(6MQ)₂Cl₂; the Co(II) and Ag(I) compounds (Co6MQ and Ag6MQ) are ionic with formulae [Ag(6MQ)₂]⁺NO₃^- and H(6MQ)⁺[Co(6MQ)Cl₃]^- (where H(6MQ)⁺ is the protonated ligand). We found that the copper complex, outperformed the Co(II), Zn(II) and Ag(I) complexes with a lower IC₅₀ (57.9 µM) in A549 cells exposed for 24 h. Cu6MQ decreased cell proliferation and induced oxidative stress detected with H₂DCFDA at 40 µM, which reduces GSH/GSSG ratio. This redox imbalance induced oxidative DNA damage revealed by the Micronucleus test and the Comet assay, which turned into a cell cycle arrest at G2/M phase and induced apoptosis. In multicellular spheroids, the IC₅₀ values tripled the monolayer model (187.3 µM for 24 h). At this concentration, the proportion of live/dead cells diminished, and the spheroids could not proliferate or invade. Although Zn6MQ also decreased GSH/GSSG ratio from 200 µM and the cytotoxicity is related to oxidative stress, the induction of the hydrogen peroxide levels only doubled the control value. Zn6MQ induced S phase arrest, which relates with the increased micronucleus frequency and with the induction of necrosis. Finally, our results reveal a synergistic activity with a 1:1 ratio of both complexes in the monolayer and multicellular spheroids.

Induction of cell cycle arrest and apoptosis by copper complex Cu(SBCM)2 towards oestrogen-receptor positive MCF-7 breast cancer cells

Copper complexes have the potential to be developed as targeted therapy for cancer because cancer cells take up larger amounts of copper than normal cells. Copper complex Cu(SBCM)₂ has been reported to induce cell cycle arrest and apoptosis towards triple-negative breast cancer cells. Nevertheless, its effect towards other breast cancer subtypes has not been explored. Therefore, the present study was conducted to investigate the effect of Cu(SBCM)₂ towards oestrogen-receptor positive MCF-7 breast cancer cells. Growth inhibition of Cu(SBCM)₂ towards MCF-7 and human non-cancerous MCF-10A breast cells was determined by MTT assay. Morphological changes of Cu(SBCM)₂-treated-MCF-7 cells were observed under an inverted microscope. Annexin V/PI apoptosis assay and cell cycle analysis were evaluated by flow cytometry. The expression of wild-type p53 protein was evaluated by Western blot analysis. The intracellular ROS levels of MCF-7 treated with Cu(SBCM)₂ were detected using DCFH-DA under a fluorescence microscope. The cells were then co-treated with Cu(SBCM)₂ and antioxidants to evaluate the involvement of ROS in the cytotoxicity of Cu(SBCM)₂. Docking studies of Cu(SBCM)₂ with DNA, DNA topoisomerase I, and human ribonucleotide reductase were also performed. The growth of MCF-7 cells was inhibited by Cu(SBCM)₂ in a dose-dependent manner with less toxicity towards MCF-10A cells. It was found that Cu(SBCM)₂ induced G₂/M cell cycle arrest and apoptosis in MCF-7 cells, possibly via a p53 pathway. Induction of intracellular ROS was not detected in MCF-7 cells. Interestingly, antioxidants enhance the cytotoxicity of Cu(SBCM)₂ towards MCF-7 cells. DNA topoisomerase I may be the most likely target that accounts for the cytotoxicity of Cu(SBCM)₂.

Cu(SBCM)₂ binds to DNA topoisomerase I, which, in turn, induces cell cycle arrest and apoptosis in MCF-7 breast cancer cells, possibly via p53 signalling pathway.