Low concentration of quercetin antagonizes the cytotoxic effects of anti-neoplastic drugs in ovarian cancer

Pterostilbene Induces Pyroptosis in Breast Cancer Cells through Pyruvate Kinase 2/Caspase-8/Gasdermin C Signaling Pathway

The incidence and mortality of breast cancer increase year by year, and it is urgent to find high-efficiency and low-toxicity anti-cancer drugs. Pterostilbene (PTE) is a natural product with antitumor activity, but the specific antitumor mechanism is not very clear. Aerobic glycolysis is the main energy supply for cancer cells. Pyroptosis is an inflammatory, programmed cell death. The aim of this study was to investigate the effect of PTE on glycolysis and pyroptosis in EMT6 and 4T1 cells and the specific mechanism, and to elucidate the role of pyruvate kinase 2 (PKM2), a key enzyme in glycolysis, in the antitumor role of PTE. Our study suggested that PTE induced pyroptosis by inhibiting tumor glycolysis. PKM2 played an important role in both the inhibition of glycolysis and the induction of pyroptosis by PTE.

Revitalizing premature ovarian failure: quercetin counteracts imatinib-induced apoptosis via the PI3K/AKT signaling pathway based on network pharmacology

As a commonly used first-line targeted drug, imatinib (Ima) is widely used first-line treatment for cancer patients. Patient survival is significantly prolonged, but Ima can cause premature ovarian failure (POF) and affect fertility. However, the underlying mechanism is unknown, and no effective method can be employed to improve this process. To investigate the effect of quercetin (Que) on Ima-induced POF and the underlying mechanism. The therapeutic impact of Que on Ima-induced POF in mice was clarified via molecular biology experiments and in vivo experiments in animals. To verify the underlying mechanism, network pharmacology was employed to construct a signaling network of Que-Ima-POF-related genes, followed by molecular biology and docking analysis. Network pharmacology analysis identified 38 therapeutic targets of Que in Ima-induced POF. The KEGG pathways of these genes were enriched for the phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt) signaling pathway. Molecular docking analysis revealed that the epidermal growth factor receptor (EGFR) is a shared target of Que, Ima, and POF and has strong binding affinity. Hematoxylin-eosin (HE) staining and ELISA confirmed that Que can partially restore the ovarian index and function of mice with Ima-induced POF. Western blot, TUNEL, and immunohistochemical staining confirmed that Que promoted the PI3K/Akt signaling pathway and reduced apoptosis in Ima-induced POF mice. Thus, Que could inhibit apoptosis in Ima-induced POF by activating the PI3K/Akt pathway.

Nano Drug Delivery Strategies for an Oral Bioenhanced Quercetin Formulation

Quercetin, a naturally occurring flavonoid, has been credited with a wide spectrum of therapeutic properties. However, the oral use of quercetin is limited due to its poor water solubility, low bioavailability, rapid metabolism, and rapid plasma clearance. Quercetin has been studied extensively when used with various nanodelivery systems for enhancing quercetin bioavailability. To enhance its oral bioavailability and efficacy, various quercetin-loaded nanosystems such as nanosuspensions, polymer nanoparticles, metal nanoparticles, emulsions, liposomes or phytosomes, micelles, solid lipid nanoparticles, and other lipid-based nanoparticles have been investigated in in-vitro cells, in-vivo animal models, and humans. Among the aforementioned nanosystems, quercetin phytosomes are attracting more interest and are available on the market. The present review covers insights into the possibilities of harnessing quercetin for several therapeutic applications and a special focus on anticancer applications and the clinical benefits of nanoquercetin formulations.

Anticancer Potential of Flavonoids: An Overview with an Emphasis on Tangeretin

Natural compounds with pharmacological activity, flavonoids have been the subject of an exponential increase in studies in the field of scientific research focused on therapeutic purposes due to their bioactive properties, such as antioxidant, anti-inflammatory, anti-aging, antibacterial, antiviral, neuroprotective, radioprotective, and antitumor activities. The biological potential of flavonoids, added to their bioavailability, cost-effectiveness, and minimal side effects, direct them as promising cytotoxic anticancer compounds in the optimization of therapies and the search for new drugs in the treatment of cancer, since some extensively antineoplastic therapeutic approaches have become less effective due to tumor resistance to drugs commonly used in chemotherapy. In this review, we emphasize the antitumor properties of tangeretin, a flavonoid found in citrus fruits that has shown activity against some hallmarks of cancer in several types of cancerous cell lines, such as antiproliferative, apoptotic, anti-inflammatory, anti-metastatic, anti-angiogenic, antioxidant, regulatory expression of tumor-suppressor genes, and epigenetic modulation.

The Role of Natural and Semi-Synthetic Compounds in Ovarian Cancer: Updates on Mechanisms of Action, Current Trends and Perspectives

Ovarian cancer represents a major health concern for the female population: there is no obvious cause, it is frequently misdiagnosed, and it is characterized by a poor prognosis. Additionally, patients are inclined to recurrences because of metastasis and poor treatment tolerance. Combining innovative therapeutic techniques with established approaches can aid in improving treatment outcomes. Because of their multi-target actions, long application history, and widespread availability, natural compounds have particular advantages in this connection. Thus, effective therapeutic alternatives with improved patient tolerance hopefully can be identified within the world of natural and nature-derived products. Moreover, natural compounds are generally perceived to have more limited adverse effects on healthy cells or tissues, suggesting their potential role as valid treatment alternatives. In general, the anticancer mechanisms of such molecules are connected to the reduction of cell proliferation and metastasis, autophagy stimulation and improved response to chemotherapeutics. This review aims at discussing the mechanistic insights and possible targets of natural compounds against ovarian cancer, from the perspective of medicinal chemists. In addition, an overview of the pharmacology of natural products studied to date for their potential application towards ovarian cancer models is presented. The chemical aspects as well as available bioactivity data are discussed and commented on, with particular attention to the underlying molecular mechanism(s).

Hydroxyapatite microbeads containing BMP-2 and quercetin fabricated via electrostatic spraying to encourage bone regeneration

BACKGROUND

Hydroxyapatite (HAp) possesses osteoconductive properties, and its granular form can serve as an effective drug delivery vehicle for bone regeneration. Quercetin (Qct), a plant-derived bioflavonoid, is known to promote bone regeneration; however, its comparative and synergistic effects with the commonly used bone morphogenetic protein-2 (BMP-2) have not been investigated.

METHODS

We examined the characteristics of newly formed HAp microbeads using an electrostatic spraying method and analyzed the in vitro release pattern and osteogenic potential of ceramic granules containing Qct, BMP-2, and both. In addition, HAp microbeads were transplanted into a rat critical-sized calvarial defect and the osteogenic capacity was assessed in vivo.

RESULTS

The manufactured beads had a microscale size of less than 200 μm, a narrow size distribution, and a rough surface. The alkaline phosphatase (ALP) activity of osteoblast-like cells cultured with the BMP-2-and-Qct-loaded HAp was significantly higher than that of either Qct- or BMP-2-loaded HAp groups. The mRNA levels of osteogenic marker genes such as ALP and runt-related transcription factor 2 were found to be upregulated in the HAp/BMP-2/Qct group compared to the other groups. In micro-computed tomographic analysis, the amount of newly formed bone and bone surface area within the defect was significantly higher in the HAp/BMP-2/Qct group, followed by the HAp/BMP-2 and HAp/Qct groups, which is consistent with the histomorphometrical results.

CONCLUSIONS

These results imply that electrostatic spraying can be an efficient strategy to produce homogenous ceramic granules and that the BMP-2-and-Qct-loaded HAp microbeads can serve as effective implants for bone defect healing.

Dual role of quercetin in enhancing the efficacy of cisplatin in chemotherapy and protection against its side effects: a review

Chemotherapy has opened a new window in cancer therapy. However, the resistance of cancer cells has dramatically reduced the efficacy of chemotherapy. Cisplatin is a chemotherapeutic agent and its potential in cancer therapy has been restricted by resistance of cancer cells. As a consequence, the scientists have attempted to find new strategies in elevating chemotherapy efficacy. Due to great anti-tumour activity, naturally occurring compounds are of interest in polychemotherapy. Quercetin is a flavonoid with high anti-tumour activity against different cancers that can be used with cisplatin to enhance its efficacy and also are seen to sensitise cancer cells into chemotherapy. Furthermore, cisplatin has side effects such as nephrotoxicity and ototoxicity. Administration of quercetin is advantageous in reducing the adverse effects of cisplatin without compromising its anti-tumour activity. In this review, we investigate the dual role of quercetin in enhancing anti-tumour activity of cisplatin and simultaneous reduction in its adverse effects.

Therapeutic and Nutraceutical Effects of Polyphenolics from Natural Sources

The prevalence of cardiovascular disease, oxidative stress-related complications, and chronic age-related illnesses is gradually increasing worldwide. Several causes include the ineffectiveness of medicinal treatment therapies, their toxicity, their inability to provide radical solutions in some diseases, and the necessity of multiple drug therapy in certain chronic diseases. It is therefore necessary for alternative treatment methods to be sought. In this review, polyphenols were identified and classified according to their chemical structure, and the sources of these polyphenol molecules are indicated. The cardioprotective, ROS scavenging, anti-aging, anticancer properties of polyphenolic compounds have been demonstrated by the results of many studies, and these natural antioxidant molecules are potential alternative therapeutic agents.

Determination of Phenolic Compounds in Blue Corn Flour (Zea mays L.) Produced and/or Metabolized by Colletotrichum gloeosporioides in a Fermentation Process

Phenolic compounds are secondary metabolites produced by plants, and their study has been increased in recent years due to their ability to improve human health. The aim of this work was the determination of phenolic compounds presents in blue corn flour before and after a fermentation process, where different proportions were used of blue corn (Zea mays L.) flour and Czapek Dox culture medium (90 mL of culture medium with 10 g of blue corn flour, 80 mL of culture medium with 20 g of blue corn flour and 70 mL of culture medium with 30 g of blue corn flour) and were fermented at 3 different times (20, 25 and 30 days) with the Colletotrichum gloeosporioides fungus. A determination of the phenolic compounds was carried out with five standard solutions, which were cyanidin 3-glucoside (CYA), pelargonidin 3-glucoside (PEL), chlorogenic acid (CLA), quercetin (QRC) and cinnamic acid (CA). The obtained results showed the presence of CA and PEL. The most abundant phenolic compound in the fermented samples was CLA over the naturally occurring compounds in blue corn, which are CYA and PEL. QRC was the phenolic compound with the lowest concentration in blue corn flour samples fermented with Colletotrichum gloeosporioides.

miR-450a exerts oncosuppressive effects in breast carcinoma by targeting CREB1

Emerging evidence greatly implicates that microRNA-450a (miR-450a) plays an essential role in cancer pathobiology. While the pathological role of miR-450a in breast carcinogenesis remains enigmatic. Herein, we showed that miR-450a was lowly expressed in breast cancer cell lines compared with normal, and low miR-450a expression was associated with poor survival in patients with breast cancer. We revealed that miR-450a mimic transfected breast cancer cells (T47D and BT474) exhibited attenuated capacities of proliferation, migration, and invasion in vitro, and miR-450a suppressed T47D cell growth in a xenograft tumor model. Mechanistically, cAMP response element-binding protein 1 (CREB1) was negatively targeted by miR-450a, and CREB1 deletion mimicked the effects of miR-450a mimic treatment. Bioinformatics analysis further revealed that elevated expression of CREB1 correlated with poor prognosis in patients with breast cancer and miR-450a level was negatively correlated with CREB1 level in breast cancer. Additionally, miR-450a inhibited the phosphorylation of phosphatidylinositol 3-kinase/V-akt murine thymoma viral oncogene homolog (PI3K/AKT) and the activities of matrix metalloproteinase-2/9 (MMP-2/9). The following rescue assay indicated that CREB1 was implicated in the anti-tumoral effect of mR-450a in breast carcinoma. All these observations disclosed that miR-450a negatively regulates the growth and metastatic property of breast carcinoma cells.

In Vitro Study of Licorice on IL-1β-Induced Chondrocytes and In Silico Approach for Osteoarthritis

Osteoarthritis (OA) is a common degenerative joint disorder that affects joint function, mobility, and pain. The release of proinflammatory cytokines stimulates matrix metalloproteinases (MMPs) and aggrecanase production which further induces articular cartilage degradation. Hypertrophy-like changes in chondrocytes are considered to be an important feature of OA pathogenesis. A Glycyrrhiza new variety, Wongam (WG), was developed by the Korea Rural Development Administration to enhance the cultivation and quality of Glycyrrhizae Radix et Rhizoma (licorice). This study examined the regulatory effect of WG against hypertrophy-like changes such as RUNX2, Collagen X, VEGFA, MMP-13 induction, and Collagen II reduction induced by IL-1β in SW1353 human chondrocytes. Additionally, in silico methods were performed to identify active compounds in licorice to target chondrocyte hypertrophy-related proteins. WG showed inhibitory effects against IL-1β-induced chondrocyte hypertrophy by regulating both HDAC4 activation via the PTH1R/PKA/PP2A pathway and the SOX9/β-catenin signaling pathway. In silico analysis demonstrated that 21 active compounds from licorice have binding potential with 11 targets related to chondrocyte hypertrophy. Further molecular docking analysis and in vivo studies elicited four compounds. Based on HPLC, isoliquiritigenin and its precursors were identified and quantified. Taken together, WG is a potential therapeutic agent for chondrocyte hypertrophy-like changes in OA.

Redox-Modulating Capacity and Antineoplastic Activity of Wastewater Obtained from the Distillation of the Essential Oils of Four Bulgarian Oil-Bearing Roses

The wastewater from the distillation of rose oils is discharged directly into the soil because it has a limited potential for future applications. The aim of the present study was to determine in vitro the chromatographic profile, redox-modulating capacity, and antineoplastic activity of wastewater obtained by distillation of essential oils from the Bulgarian Rosa alba L., Rosa damascena Mill., Rosa gallica L., and Rosa centifolia L. We applied UHPLC-HRMS for chromatographic analysis of rose wastewaters, studied their metal-chelating and Fe(III)-reducing ability, and performed MTT assay for the evaluation of cytotoxic potential against three tumorigenic (HEPG2-hepatocellular adenocarcinoma, A-375-malignant melanoma, A-431-non-melanoma epidermoid squamous skin carcinoma) and one non-tumorigenic human cell lines (HaCaT-immortalized keratinocytes). The median inhibitory concentrations (IC₅₀) were calculated with nonlinear modeling using the MAPLE^® platform. The potential of the wastewaters to induce apoptosis was also examined. Mono-, di-, and acylated glycosides of quercetin and kaempferol, ellagic acid and its derivatives as main chemical components, and gallic acid and its derivatives-such as catechin and epicatechin-were identified. The redox-modulating capacity of the samples (TPTZ test) showed that all four wastewaters exhibited the properties of excellent heavy metal cleaners, but did not exert very strong cytotoxic effects. The lowest IC₅₀ rate was provided in wastewater from R. centifolia (34-35 µg/mL of gallic acid equivalents after a 72 h period for all cell lines). At 24 and 48 hours, the most resistant cell line was HEPG2, followed by HaCaT. After 72 h of exposure, the IC₅₀ values were similar for tumor and normal cells. Still, R. damascena had a selectivity index over 2.0 regarding A-431 non-melanoma skin cancer cells, showing a good toxicological safety profile in addition to moderate activity-IC₅₀ of 35 µg/mL polyphenols. The obtained results related to wastewaters acquired after the distillation of essential oils from the Bulgarian R. alba, R. damascena, R. gallica, and R. centifolia direct our attention to further studies for in-depth elucidation of their application as detoxifying agents under oxidative damage conditions in other experimental datasets.

Efficacy and Mechanism of Buxue Yimu Pills () on Gynecological Anemia: A Combination of Clinical and Network Pharmacology Study

OBJECTIVE

To compare the clinical efficacy and safety of oral administration of Buxue Yimu Pills (BYP, ), ferrous sulfate (FS), and the combination of BYP and FS on gynecological anemia, and investigate the mechanisms using network pharmacology.

METHODS

A randomized, controlled, multi-center clinical trial was conducted. Totally 150 patients with hemoglobin of 70-110 g/L due to gynecological conditions were recruited and randomized (using the block randomization method) into Buxue Yimu Pills group (24 g/d), oral iron group (FS Tablets, 0.9 g/d), and combined treatment group (BYP, 24 g/d plus FS Tablets, 0.9 g/d), 50 patients in each group. At the enrollment and 4-week treatment, complete blood count, serum iron indexes were evaluated. Adverse events, liver and renal functions, as well as blood coagulation were observed. Network pharmacology was conducted to identify the active ingredients and explore the potential mechanisms of BYP.

RESULTS

Ten (20%) and 7 (14%) participants discontinued the therapy due to gastrointestinal symptoms in oral iron and combination treatment groups. All 3 groups showed elevated hemoglobin. The patients in the iron group exhibited typically elevated in serum iron and ferritin and decreased in total iron-binding capacity. No change in iron indexes was observed in BYP group. The patients in the combination treatment group neither showed significant changes in serum ferritin nor total iron-binding capacity. No significant adverse reactions were observed in the BYP group. The network pharmacology identified 27 bioactive compounds and 145 targets of BYP on gynecological anemia. Biological processes and pathways including regulation of inflammation, hormone, angiogenesis and hemostasis, response to decreased oxygen levels, effects on myeloma cell, and response to metal ions were identified.

CONCLUSION

BYP contributes to the practical improvement on gynecological anemia potentially through multi-target mechanisms and optimized iron re-distribution. (Trial registration: No. NCT03232554).

Quercetin prevents primordial follicle loss via suppression of PI3K/Akt/Foxo3a pathway activation in cyclophosphamide-treated mice

BACKGROUND

Chemotherapy improves the survival rates of patients with various cancers but often causes some adverse effects, including ovarian damage, characterised by a decrease in primordial follicle stockpiles. Recent studies have revealed that chemotherapy may stimulate the PI3K signalling pathway, thereby resulting in accelerated primordial follicle activation and a decreased ovarian reserve. Quercetin is an inhibitor of the PI3K pathway; however, its protective effects against chemotherapy-induced follicle loss in mice have not been established. In this study, the effects of quercetin in a mouse model of cyclophosphamide-induced ovarian dysfunction were investigated.

METHODS

C57BL/6 female mice were used for the study. Paraffin sections of mouse ovaries (n = 30 mice) were stained with haematoxylin and eosin for differential follicle counts. Apoptosis (n = 5 mice per group) was evaluated by TUNEL assay. Immunohistochemical staining for ki67 and Foxo3a (n = 5 mice per group) was performed to evaluate the activation of primordial follicles. The role of the PI3K signalling pathway in the ovaries (n = 45 mice) was assessed by western blotting.

RESULTS

Quercetin attenuated the cyclophosphamide-induced reduction in dormant primordial follicles. Analysis of the PI3K/Akt/Foxo3a pathway showed that quercetin decreased the phosphorylation of proteins that stimulate follicle activation in cyclophosphamide-induced ovaries. Furthermore, quercetin prevented cyclophosphamide-induced apoptosis in early growing follicles and early antral follicles, maintained anti-Müllerian hormone levels secreted by these follicles, and preserved the quiescence of the primordial follicle pool, as determined by intranuclear Foxo3a staining.

CONCLUSIONS

Quercetin attenuates cyclophosphamide-induced follicle loss by preventing the phosphorylation of PI3K/Akt/Foxo3a pathway members and maintaining the anti-Müllerian hormone level through reduced apoptosis in growing follicles. Accordingly, quercetin is expected to improve fertility preservation and the prevention of endocrine-related side effects of chemotherapy.

Diabetes and Cancer: Metabolic Association, Therapeutic Challenges, and the Role of Natural Products

Cancer is considered the second leading cause of death worldwide and in 2018 it was responsible for approximately 9.6 million deaths. Globally, about one in six deaths are caused by cancer. A strong correlation was found between diabetes mellitus and carcinogenesis with the most evident correlation was with type 2 diabetes mellitus (T2DM). Research has proven that elevated blood glucose levels take part in cell proliferation and cancer cell progression. However, limited studies were conducted to evaluate the efficiency of conventional therapies in diabetic cancer patients. In this review, the correlation between cancer and diabetes will be discussed and the mechanisms by which the two diseases interact with each other, as well as the therapeutics challenges in treating patients with diabetes and cancer with possible solutions to overcome these challenges. Natural products targeting both diseases were discussed with detailed mechanisms of action. This review will provide a solid base for researchers and physicians to test natural products as adjuvant alternative therapies to treat cancer in diabetic patients.

Kaempferol and Its Glycoside Derivatives as Modulators of Etoposide Activity in HL-60 Cells

Kaempferol is a polyphenol found in a variety of plants. Kaempferol exerts antitumor properties by affecting proliferation and apoptosis of cancer cells. We investigated whether kaempferol and its glycoside derivatives-kaempferol 3-O-[(6-O-E-caffeoyl)-β-D-glucopyranosyl-(1→2)]-β-D-galactopyranoside-7-O-β-D-glucuropyranoside (P2), kaempferol 3-O-[(6-O-E-p-coumaroyl)-β-D-glucopyranosyl-(1→2)]-β-D-galactopyranoside-7-O-β-D-glucuropyranoside (P5) and kaempferol 3-O-[(6-O-E-feruloyl)-β-D-glucopyranosyl-(1→2)]-β-D-galactopyranoside-7-O-β-D-glucuropyranoside (P7), isolated from aerial parts of Lens culinaris Medik.-affect the antitumor activity of etoposide in human promyelocytic leukemia (HL-60) cells. We analyzed the effect of kaempferol and its derivatives on cytotoxicity, DNA damage, apoptosis, cell cycle progression and free radicals induced by etoposide. We demonstrated that kaempferol increases the sensitivity of HL-60 cells to etoposide but does not affect apoptosis induced by this drug. Kaempferol also reduces the level of free radicals generated by etoposide. Unlike kaempferol, some of its derivatives reduce the apoptosis of HL-60 cells (P2 and P7) and increase the level of free radicals (P2 and P5) induced by etoposide. Our results indicate that kaempferol and its glycoside derivatives can modulate the activity of etoposide in HL-60 cells and affect its antitumor efficacy in this way. Kaempferol derivatives may have the opposite effect on the action of etoposide in HL-60 cells compared to kaempferol.

Cisplatin resistance reversal in lung cancer by tumor acidity-activable vesicular nanoreactors via tumor oxidative stress amplification

Drug resistance of cisplatin significantly limits its therapeutic efficacy in clinical applications against different cancers. Herein, we develop a novel strategy to overcome cisplatin drug resistance through sensitizing cisplatin-resistant human lung cancer cells (A549R) under amplified oxidative stress using a vesicular nanoreactor for simultaneous cisplatin delivery and H₂O₂ generation. We engineer the nanoreactor by the self-assembly of the amphiphilic diblock copolymers to co-deliver glucose oxidase (GOD) and cisplatin (Cis) (Cis/GOD@Bz-V). Cis/GOD@Bz-V was rationally designed to stay impermeable during blood circulation while mild acidity (pH 6.5-6.8) can activate its molecular-weight selective membrane permeability and release cisplatin locally. Diffusion of small molecules such as oxygen and glucose across the membranes can induce the in situ generation of superfluous H₂O₂ to promote cellular oxidative stress and sensitize A549R cells via activation of pro-apoptotic pathways. Cis/GOD@Bz-V nanoreactors could effectively kill A549R at pH 6.8 in the presence of glucose by the combination of H₂O₂ generation and cisplatin release. Growth of A549R xenograft tumors can be inhibited efficiently without the obvious toxic side effects via the systemic administration of Cis/GOD@Bz-V. Accordingly, the tumor acidity-activable cisplatin-loaded nanoreactors show great potential to enhance the therapeutic efficacy against cisplatin-resistant cancers.

Chemoresistance in Ovarian Cancer: Prospects for New Drugs

This review focuses on the conventional treatment, signaling pathways and various reasons for drug resistance with an understanding of novel methods that can lead to effective therapies. Ovarian cancer is amongst the most common gynecological and lethal cancers in women affecting different age groups (20-60). The survival rate is limited to 5 years due to diagnosis in subsequent stages with a reoccurrence of tumor and resistance to chemotherapeutic therapy. The recent clinical trials use the combinatorial treatment of carboplatin and paclitaxel on ovarian cancer after the cytoreduction of the tumor. Predominantly, patients are responsive initially to therapy and later develop metastases due to drug resistance. Chemotherapy also leads to drug resistance causing enormous variations at the cellular level. Multifaceted mechanisms like drug resistance are associated with a number of genes and signaling pathways that process the proliferation of cells. Reasons for resistance include epithelial-mesenchyme, DNA repair activation, autophagy, drug efflux, pathway activation, and so on. Determining the routes on the molecular mechanism that target chemoresistance pathways are necessary for controlling the treatment and understanding efficient drug targets can open light on improving therapeutic outcomes. The most common drug used for ovarian cancer is Cisplatin that activates various chemoresistance pathways, ultimately causing drug resistance. There have been substantial improvements in understanding the mechanisms of cisplatin resistance or chemo sensitizing cisplatin for effective treatment. Therefore, using therapies that involve a combination of phytochemical or novel drug delivery system would be a novel treatment for cancer. Phytochemicals are plant-derived compounds that exhibit anti-cancer, anti-oxidative, anti-inflammatory properties and reduce side effects exerted by chemotherapeutics.

Effects of Quercetin on the Efficacy of Various Chemotherapeutic Drugs in Cervical Cancer Cells

Purpose

This study aimed to investigate the effects of quercetin on the efficacy of various chemotherapeutic drugs in cervical cancer cells.

Methods

All drug experiments were performed in HeLa and SiHa cells. The cell viability was detected by Cell Counting Kit-8 assay, and cell proliferation was estimated by bromodeoxyuridine assay. CompuSyn software was utilized to calculate the combination index (CI) and evaluate the synergistic or antagonistic effect of quercetin with cisplatin, paclitaxel, 5-fluorouracil and doxorubicin on cell viability. Cell migration and invasion abilities were detected by transwell assays, and cell apoptosis was measured by flow cytometry. The expression levels of matrix metallopeptidase 2 (MMP2), ezrin, P-glycoprotein (P-Gp) and methyltransferase-like 3 (METTL3) protein treated with various drugs were analyzed by Western blotting.

Results

Quercetin inhibited the viability of HeLa and SiHa cells in a dose- and time-dependent manner. The CI values of quercetin with cisplatin, paclitaxel, 5-fluorouracil and doxorubicin were <1, >1, >1 and >1, respectively. The effect of combination of quercetin and cisplatin on cell proliferation was stronger than their individual effects. Co-treatment group could inhibit more cell migration and invasion in contrast to single-drug group. Besides, quercetin combined with cisplatin group induced more cell apoptosis in contrast to single-drug group. The results of Western blotting showed that the expression levels of MMP2, ezrin, P-Gp and METTL3 in co-treatment group were lower than in cisplatin group, respectively.

Conclusion

Quercetin and cisplatin had synergistic inhibitory effect on cervical cancer cells. Quercetin might enhance the antitumor effect of cisplatin via inhibiting proliferation, migration and invasion and elevating apoptosis through weakening MMP2, ezrin, METTL3 and P-Gp expression of cancer cells.

Concentration-Dependent Pro- and Antitumor Activities of Quercetin in Human Melanoma Spheroids: Comparative Analysis of 2D and 3D Cell Culture Models

Quercetin, a dietary flavonoid found in fruits and vegetables, has been described as a substance with many anti-cancer properties in a variety of preclinical investigations. In the present study, we demonstrate that 2D and 3D melanoma models exhibit not only different sensitivities to quercetin, but also opposite, cancer-promoting effects when metastatic melanoma spheroids are treated with quercetin. Higher concentrations of quercetin reduce melanoma growth in three tested cell lines, whereas low concentrations induce the opposite effect in metastatic melanoma spheroids but not in the non-metastatic cell line. High (>12.5 µM) or low (<6.3 µM) quercetin concentrations decrease or enhance cell viability, spheroid size, and cell proliferation, respectively. Additionally, melanoma cells cultivated in 2D already show significant caspase 3 activity at very low concentrations (>0.4 µM), whereas in 3D spheroids apoptotic cells, caspase 3 activity can only be detected in concentrations ≥12.5 µM. Further, we show that the tumor promoting or repressing effect in the 3D metastatic melanoma spheroids are likely to be elicited by a precisely controlled regulation of Nrf2/ARE-mediated cytoprotective genes, as well as ERK and NF-κB phosphorylation. According to the results obtained here, further studies are needed to better characterize the mechanisms of action underlying the pro- and anti-carcinogenic effects of quercetin on human melanomas.

Plant isoflavones can affect accumulation and impact of silver and titania nanoparticles on ovarian cells

Objectives. The application of nanoparticles is experiencing a rapid growth, but it faces a problem of their toxicity, especially adverse effects on female reproduction. Food and medicinal plants and their isoflavones can be protectors against environmental stressors, but their ability to abate the adverse effects of nanoparticles has not been studied yet. In the present study, we examined the effect of silver (AgNPs) and titanium dioxide (titania, TiO2NPs) nanoparticles alone or in combination with plant phytoestrogens/antioxidants (resveratrol, diosgenin, and quercetin) on accumulation of nanoparticles, and progesterone release by cultured porcine ovarian granulosa cells.Methods. Porcine granulosa cells were incubated in the presence of AgNPs or TiO2NPs (0.1, 1, 10 or 100 µg/ml) alone or in combination with resveratrol, diosgenin or quercetin (10 µg/ml) for 48 h. The accumulation of tested nanoparticles by granulosa cells was assessed under light microscope. Progesterone concentration in culture media was measured by ELISA kit.Results. Cells accumulated both AgNPs and TiO2NPs in a dose-dependent manner. AgNPs, but not TiO2NPs, at highest dose (100 µg/ml) resulted in a destruction of cell monolayer. Both Ag-NPs and TiO2NPs reduced progesterone release. Resveratrol, diosgenin, and quercetin promoted accumulation of both AgNPs and TiO2NPs in ovarian cells and inhibited the progesterone output. Furthermore, resveratrol and diosgenin, but not quercetin, prevented the suppressive action of both AgNPs, and TiO2NPs on progesterone release.Conclusions. These observations (1) demonstrate accumulation of AgNPs and TiO2NPs in ovarian cells, (2) confirm the toxic impact of AgNPs, and TiO2NPs on these cells, (3) confirm the inhibitory effects of plant polyphenols/phytoestrogens on ovarian steroidogenesis, (4) show the ability of these isoflavones to increase the accumulation of AgNPs and TiO2NPs, and (5) show their ability to reduce the suppressive effect of AgNPs and TiO2NPs on ovarian progesterone release. The suppressive effect of AgNPs and TiO2NPs on ovarian functions should be taken into account by their exposition. However, these adverse effects could be mitigated by some plant isoflavones.

Comprehensive Review of Methodology to Detect Reactive Oxygen Species (ROS) in Mammalian Species and Establish Its Relationship with Antioxidants and Cancer

Evidence suggests that reactive oxygen species (ROS) mediate tissue homeostasis, cellular signaling, differentiation, and survival. ROS and antioxidants exert both beneficial and harmful effects on cancer. ROS at different concentrations exhibit different functions. This creates necessity to understand the relation between ROS, antioxidants, and cancer, and methods for detection of ROS. This review highlights various sources and types of ROS, their tumorigenic and tumor prevention effects; types of antioxidants, their tumorigenic and tumor prevention effects; and abnormal ROS detoxification in cancer; and methods to measure ROS. We conclude that improving genetic screening methods and bringing higher clarity in determination of enzymatic pathways and scale-up in cancer models profiling, using omics technology, would support in-depth understanding of antioxidant pathways and ROS complexities. Although numerous methods for ROS detection are developing very rapidly, yet further modifications are required to minimize the limitations associated with currently available methods.

4-Hydroxyhalcone effects on cisplatin-induced genotoxicity model

BACKGROUND

The genotoxicity of cisplatin (CP) as a platinum-based antineoplastic agent due to its oxidative stress induction was well known. In this research, we examined 4-hydroxychalcone (4-HCH) as a natural food that presents flavonoid effects on reactive oxygen species (ROS) production and CP-induced in vivo genotoxicity.

METHOD AND MATERIALS

Cytotoxicity of CP and 4-HCH was measured on human embryonic kidney 293 cells with MTT assay. Then, intracellular ROS content at IC50 concentration of CP was measured with 2',7'-dichlorofluorescein diacetate (DCFDA) dye. Finally, 4-HCH was administered intraperitoneally at 10 and 40 mg/kg/BW doses as a pre and post-treatment schedule in a mice model of CP genotoxicity (7 mg/kg). Acridine-orange-stained bone marrow cells were quantified for micronucleus presence examination.

RESULTS

The calculated IC50 of CP and 4-HCH were reported around 19.4 and 133.6 μM, respectively, on HEK293 cells. Also, it was observed that 4-HCH at 0.2, 2 and 10 μM concentrations did not show obvious cytotoxicity. The fluorimetry confirmed that pre-treatment with 10 μM and co-treatment with 2 μM of 4-HCH could attenuate the CP-induced ROS production (P < 0.05 and P < 0.01, respectively). Also, the lowest micronucleated cells were seen in 10 mg/kg 4-HCH-treated group after CP exposure (39 ± 7.9, P < 0.0001).

DISCUSSION

Our results demonstrated the antigenotoxic action of 4-HCH in CP-treated mice bone marrow cells for the first time in both concentrations of 10 and 40 mg/kg especially in the form of co-treatment. Further studies required clinical application of this compound in a combination of CP to attenuate the normal cells' genotoxicity side effects.

Interactions between Cisplatin and Quercetin at Physiological and Hyperthermic Conditions on Cancer Cells In Vitro and In Vivo

Quercetin (QU), a hyperthermic sensitizer, when combined with cisplatin (CP) affects tumor growth. To determine the effects of QU and CP and their interactions, multimodal treatment in vitro and in vivo models under physiological and hyperthermic conditions was performed. In vitro, different sensitivity of T24 and UMUC human bladder cancer cells was observed after short-term exposure to QU (2 h) and CP (1 h). Effects of both compounds were investigated at low and high micromolar concentrations (1 and 50 µM, respectively) under both thermal conditions. QU acted in additive or synergistic manner in combination with CP between physiological condition and hyperthermia. As determined by 3-(4,5-dimethylthiazol2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, short-term application of QU and CP reduced cell viability. Clonal assay also indicated that combined treatment with QU and CP is lethal to bladder cancer cells in both conditions. In vivo, CP (5 or 10 mg kg⁻¹) and QU (50 mg kg⁻¹) acted synergistically with hyperthermia (43 °C) and inhibited tumor growth, activated immune effectors and increased mice survival. Our results demonstrate that combined treatment with CP and QU may increase death of tumor cells in physiological and hyperthermic conditions which could be clinically relevant in locoregional chemotherapy.

Overview of biological effects of Quercetin on ovary

Over the last few decades, using natural products has been increased to treat different diseases. Today, great attention has been pointed toward the usage of natural products such as flavonoids, especially Quercetin (QUR), in the treatment of diseases. QUR as a natural antioxidant has been traditionally used to prevent or treat a variety of diseases such as cancer, cardiovascular disease, polycystic ovary syndrome (PCOS), obesity, chronic inflammation, and reproductive system dysfunction. Several studies demonstrated that QUR acts as an anti-inflammatory, anti-apoptotic, antioxidant, and anticancer agent. With this in view, in this study, we intended to describe an overview of the biological effects of QUR on the ovary. QUR improves the quality of oocytes and embryos. It affects the proliferation and apoptosis and decreases the oxidative stress in granulosa cells (GCs). Furthermore, QUR can be used as a complementary and alternative therapy in ovarian cancer and it has beneficial effects in the treatment of PCOS patients. It seems that QUR as a supplementary factor has different activities for the treatment of different disorders and it also has bidirectional activities. However, further investigations are needed for understanding the efficacy of QUR in the treatment and improvement of gynecological patients.

Quercetin protects the buffalo rat liver (BRL-3A) cells from aflatoxin B1-induced cytotoxicity via activation of Nrf2-ARE pathway

Aflatoxin B1 (AFB1) is the most toxic mycotoxin widely presented in agricultural products, and the protective effect of quercetin (QUE), a natural antioxidant, against AFB1-induced cytotoxicity to the buffalo rat liver (BRL-3A) cells was investigated. With an IC50 of 23 μM, AFB1 induced a significant oxidative stress to BRL-3A cells evidenced by a dose-dependent reduction of mitochondria membrane potential (MMP), ATP content, and activities of endogenous antioxidant enzymes along with increased levels of reactive oxygen species (ROS) and lipid peroxidation biomarker of malondialdehyde (MDA). The activity of CYP1A2, the key enzyme to convert AFB1 to reactive AFB1 exo-8,9- epoxide, was also increased, which, probably in together with ROS, led to cell apoptosis with DNA fragmentation, chromatin condensation and increased lactate dehydrogenase release. After the BRL cells were pre-treated by low level QUE (2.5 and/or 5 μM) for 24 h and then exposed to AFB1, the activities of antioxidant enzymes including haeme oxygenase-1, glutathione S-transferase, superoxide dismutase, and the ratio of reduced to oxidised glutathione were significantly increased whereas the levels of intracellular ROS and MDA were reduced. The QUE pre-treatment also increased the levels of MMP, ATP and DNA integrity, and reduced the expression of apoptosis related genes of Bax and Caspase-3. The Western blotting study revealed increased content of phosphorylated Akt and nuclear NF-E2-related factor 2 (Nrf2), indicating an activation of Nrf2-ARE pathway in counteracting oxidative stress and cytotoxicity of AFB1. Thus, the QUE pre-treatment enhanced the anti-stress capacity of the cells through the activation of the Nrf2-ARE pathway, and QUE-based measures could be developed to ameliorate the toxicity caused by AFB1.

Quercetin Enhanced Paclitaxel Therapeutic Effects Towards PC-3 Prostate Cancer Through ER Stress Induction and ROS Production

Introduction

Prostate cancer is one of the most common cancers threatening public health worldwide. Although chemotherapy plays an important role in treating prostate cancer, it leads to many adverse effects and is prone to drug resistance. Quercetin, a natural product, is used in traditional Chinese medicine because of its strong antitumor activity and few side effects.

Methods

In this study, we combined quercetin and paclitaxel to kill prostate cancer cells in vivo and in vitro, and we investigated the relevant mechanism of this combination treatment. After the cancer cells were treated with quercetin or/and paclitaxel, cell growth inhibition, apoptosis, the cell cycle, reactive oxygen species (ROS) generation, and several endoplasmic reticulum (ER) stress signaling pathway related gene expressions were evaluated.

Results

The combined treatment with quercetin and paclitaxel significantly inhibited cell proliferation, increased apoptosis, arrested the cell cycle at the G2/M phase, inhibited cell migration, dramatically induced ER stress to occur, and increased ROS generation. In a PC-3 cancer-bearing murine model, this combination treatment exerted the most beneficial therapeutic effects, and quercetin increased the cancer cell-killing effects of paclitaxel, with nearly no side effects compared with the single paclitaxel treatment group.

Conclusion

Combination treatment possessed enhanced anti-cancer effects, and these results will provide a basis for treating prostate cancer using a combination of quercetin and paclitaxel.

The Role of Antioxidants in Cancer, Friends or Foes?

Consumption of dietary supplements by millions of people is increasing [1]. Between 64 to 81% of cancer patients and survivors use multivitamin supplements after the cancer diagnosis [2]. The use of antioxidants during cancer therapy has been a hot topic in medical science for the last 20 years without clear answers and recommendations. It seems that antioxidants are able to I) decrease the cancer formation risk by quenching ROS that are involved in cancer initiation and progression and II) assist in survival of cancer/precancer cells once the malignant transformation already occurred. Antioxidants were shown to assist cancer initiation, interfere with cancer treatment by reducing its efficacy and patient survival, and vice versa, there are reports of beneficial antioxidant effect during the cancer treatment.

Therapeutic and preventive properties of honey and its bioactive compounds in cancer: an evidence-based review

Despite the much improved therapeutic approaches for cancer treatment that have been developed over the past 50 years, cancer remains a major cause of mortality globally. Considerable epidemiological and experimental evidence has demonstrated an association between ingestion of food and nutrients with either an increased risk for cancer or its prevention. There is rising interest in exploring agents derived from natural products for chemoprevention or for therapeutic purposes. Honey is rich in nutritional and non-nutritional bioactive compounds, as well as in natural antioxidants, and its potential beneficial function in human health is becoming more evident. A large number of studies have addressed the anti-cancer effects of different types of honey and their phenolic compounds using in vitro and in vivo cancer models. The reported findings affirm that honey is an agent able to modulate oxidative stress and has anti-proliferative, pro-apoptotic, anti-inflammatory, immune-modulatory and anti-metastatic properties. However, despite its reported anti-cancer activities, very few clinical studies have been undertaken. In the present review, we summarise the findings from different experimental approaches, including in vitro cell cultures, preclinical animal models and clinical studies, and provide an overview of the bioactive profile and bioavailability of the most commonly studied honey types, with special emphasis on the chemopreventive and therapeutic properties of honey and its major phenolic compounds in cancer. The implications of these findings as well as the future prospects of utilising honey to fight cancer will be discussed.

cRGDfK-Grafted Small-Size Quercetin Micelles For Enhancing Therapy Efficacy Of Active Ingredient From The Chinese Medicinal Herb

Background

As an active ingredient of Chinese herbal medicine, quercetin (QU) can significantly induce apoptosis of tumor cells and give play to other effect such as decreasing both fibroblast population and collagen in cancer cell nest. However, the antitumor efficacy of quercetin was mostly evaluated at cellular level and rarely developed in vivo by intravenous injection, which may be ascribed to its inferior physicochemical properties including water insolubility, short plasma half-time, and insufficient enrichment in the tumor tissues.

Methods

The DSPE-PEG was used to construct quercetin-loaded micelles, and the integrin ligand cRGDfK was grafted to modify the nanocarrier for enhancing its cancer-specific homing. The MALDI-TOF-MS, DLS, TEM, and UV were orderly operated to characterize guidance molecules and micelles by morphology, size distribution, Zeta potential, and drug encapsulation efficiency. In addition, the surface plasmon resonance study and real-time confocal analysis were employed to demonstrate α_vβ₃ integrin-overexpressing B16 cells-specific binding and uptake. After further pharmacodynamics studies in vitro and in vivo, we also evaluate systemic toxicity about cRGDfK-PM-QU.

Results

The cRGDfK was successfully stitched with DSPE-PEG and modified on the surface of micelles. The ligand modification enhanced the negative charges of the micelles, but it did not induce significant changes in particle size. The quercetin micelles were about 15 nm in size and negatively charged, and had spherical morphology and high drug encapsulation efficiency. In vitro, the cRGDfK-modified micelles (cRGDfK-PM) showed α_vβ₃ integrin-overexpressing B16 cells-specific binding and uptake, and cRGDfK-PM-QU (QU loaded in cRGDfK-PM) induced more significant cell apoptosis and cytotoxic effects against B16 tumor cells than counterpart micelles (PM-QU). In vivo, the cRDGfK modification enhanced enrichment in B16 tumor tissue, improved the therapeutic efficacy of the quercetin-loaded micelles against B16 tumor, and exhibited lower systemic and pulmonary toxicity compared with counterpart micelles in the mouse mode.

Conclusion

Quercetin as a natural product has triggered increasing interest in the antitumor field. In this study, cRGDfK-modified DSPE-PEG micelles significantly optimized quercetin therapeutic efficacy and pulmonary toxicity as well as lowered systemic toxicity.

Anthocyanins, delphinidin-3-O-glucoside and cyanidin-3-O-glucoside, inhibit immune checkpoints in human colorectal cancer cells in vitro and in silico

The objective was to assess anti-progression and stimulatory immune response effects among anthocyanins (ANC) and their metabolites on human colorectal cancer cells in vitro and in silico. Pure phenolics including delphinidin-3-O-glucoside (D3G) and its metabolites, delphinidin (DC) and gallic acid (GA), were tested alone or in combination, on HCT-116 and HT-29 human colorectal cancer cells (100-600 µg/mL). HCT-116 and HT-29 50% inhibition concentrations (µg/mL) were 396 ± 23 and 329 ± 17 for D3G; 242 ± 16 and >600 for DC; and 154 ± 5 and 81 ± 5 for GA, respectively. Using molecular docking, cyanidin-3-O-glucoside (C3G) showed the highest potential to inhibit immune checkpoints: programmed cell death protein-1 (PD-1) (-6.8 kcal/mol) and programmed death-ligand-1 (PD-L1) (-9.6 kcal/mol). C3G, D3G, DC, GA, and D3G-rich extracts decreased PD-L1 protein expression in HCT-116 cells. C3G decreased PD-L1 fluorescence intensity by 39%. ANC decreased PD-1 expression in peripheral blood mononuclear cells in monoculture by 41% and 55%, and co-culture with HCT-116 and HT-29 cells by 39% and 26% (C3G) and 50% and 51% (D3G), respectively. D3G and C3G, abundant in plant foods, showed potential for binding with and inhibiting immune checkpoints, PD-1 and PD-L1, which can activate immune response in the tumor microenvironment and induce cancer cell death.

Polyphenols enhance the activity of alkylating agents in leukaemia cell lines

Polyphenols have been shown to sensitize solid tumours to alkylating agents such as cisplatin, and induce apoptosis and/or cell-cycle arrest. Here, we assess the effects of five polyphenols alone and in combination with three alkylating agents: cisplatin, cyclophosphamide and chlorambucil in lymphoid and myeloid leukaemia cells lines, and non-tumour control cells. In lymphoid leukaemia cell lines there was a synergistic reduction in ATP and glutathione levels, an induction of cell cycle arrest, DNA damage and apoptosis when quercetin, apigenin, emodin and rhein were combined with cisplatin and cyclophosphamide; and when apigenin and rhein were combined with chlorambucil. In myeloid leukaemia cells quercetin, apigenin and emodin showed a similar synergistic effect with all alkylating agents; however antagonistic effects were observed with some or all alkylating agents when combined with emodin, rhein and cis-stilbene. All synergistic effects were associated with reduced glutathione levels, DNA damage and apoptosis; whilst during antagonism the reverse effects were observed. The combination of alkylating agents, particularly cisplatin with polyphenols could be promising for the treatment of lymphoid leukaemias, with apigenin showing the greatest effects. Likewise in myeloid cells apigenin also synergised the action of all alkylating agents, suggesting that apigenin may also be beneficial in myeloid leukaemias.

Quercetin shows anti-tumor effect in hepatocellular carcinoma LM3 cells by abrogating JAK2/STAT3 signaling pathway

Objective

Hepatocellular carcinima is one of the most common tumors in clinic and also one of the leading causes of death from cancer worldwide. Quercetin shows significant effects on blocking the development of various cancers.

Methods

We used the human hepatocellular carcinoma LM3 and nude mice tumor model to assess the effects of quercetin in hepatocellular carcinoma and clarify its mechanism of action. We collected LM3 cell line treated with different doses of quercetin at different time periods and determined the vital indexes. The liver tissues of mice were collected and used for western boltting (WB), Hematoxylin and Eosin (H&E) and TUNEL staining.

Results

Results indicated that quercetin suppressed the Hepatocellular carcinoma (HCC) growth both in vivo and in vitro. Quercetin could disturb LM3 cells proliferation and cell cycle distribution, thus inducing apoptosis. At the same time, quercetin inhibited LM3 cells migration and invasion and promoted HCC autophagy. These effects at least partly depended on the down‐regulation of the activation of JAK2 and STAT3 by quercetin.

Conclusion

Quercetin inhibited hepatocellular carcinoma progression by modulating cell apoptosis, migration, invasion, and autophagy; and its effects were at least partly related with the JAK2/STAT3 signaling pathway.

Berberine Effects on NFκB, HIF1A and NFE2L2/AP-1 Pathways in HeLa Cells

Background:

Berberine has multitudinous anti-cancer stem cells effects making it a highly promising candidate substance for the next-generation cancer therapy. However, berberine modes of action predispose it to significant side-effects that probably limit its clinical testing and application.

Materials and Methods:

HeLa cells were treated with two concentrations of berberine (30 and 100 µM) for 24 hours to assess the functioning of the NFE2L2/AP-1, NFκB and HIF1A pathways using 22 RNAs expression qPCR-based analysis.

Results:

Berberine effects appeared to be highly dose-dependent, with the lower concentration being capable of suppressing the NFκB functioning and the higher concentration causing severe signaling side-effects seen in the HIF1A pathway and the NFE2L2 sub-pathways, and especially and more importantly in the AP-1 sub-pathway.

Conclusion:

The results of the study suggest that berberine has clinically valuable anti-NFκB effects however jeopardized by its side effects on the HIF1A and especially NFE2L2/AP-1 pathways, its therapeutic window phenomenon and its cancer type-specificity. These, however, may be ameliorated using the cocktail approach, provided there is enough data on signaling effects of berberine.

Quercetin: a natural compound for ovarian cancer treatment

Ovarian cancer is the main cause of death among all reproductive cancers in females. In 2018, ovarian cancer was the seventh most common cancer of women entire the world. A wide variety of molecular and genetic alterations as well as different response to therapies in the different types of ovarian cancer lead to problems in design a common therapeutic strategy. Besides, ovarian cancer cells have tendency to acquire resistance to common cancer treatments through multiple mechanisms. Various factors, including cytokines, growth factors, proteases, adhesion molecules, coagulation factors, hormones and apoptotic agents have been examined to find effective cancer treatment. Phytochemicals have been indicated to have great potential anti-cancer properties against various types of cancers. Quercetin is one of the phytochemicals that exists extensively in daily foods. Wide evidences revealed that quercetin is able to inhibit various types of cancers including breast, lung, nasopharyngeal, kidney, colorectal, prostate, pancreatic, and ovarian cancer. Several in vitro and in vivo studied conducted to evaluate cytotoxic effects of quercetin on ovarian cancer. Since quercetin does not harm healthy cells and it is cytotoxic to cancer cells via various mechanisms, researchers suggest that it could be an ideal agent for ovarian cancer treatment or an adjuvant agent in combination with other anti-cancer drugs. Thus, in this review, we focused on chemo-preventive and curative attitude of quercetin for ovarian cancer and summarize some of the most recent findings which regard the possible molecular mechanisms by which this natural compound inhibits this cancer.

Protective effects of quercetin against inflammation and oxidative stress in a rabbit model of knee osteoarthritis

Hit, Lead & Candidate Discovery This study investigated the effects of a natural phenolic compound quercetin on surgical-induced osteoarthritis (OA) in rabbits. Forty-eight New Zealand White rabbits were used to establish OA model by Hulth modified method, and subsequently randomized into untreated OA group (treatment was drinking water), celecoxib treated group (celecoxib 100 mg kg^-1 by gavage), and quercetin treated group (25 mg kg^-1 by gavage). Sixteen nonoperated rabbits served as the normal controls (drinking water was given). The treatment (length: 4 weeks) started on the 5th week postoperation when the OA pathological changes were manifested. Expressions of superoxide dismutase (SOD), matrix metalloproteinase-13 (MMP-13) and tissue inhibitor of metalloproteinases-1 (TIMP-1) in serum, synovial fluid, and synovial tissue were measured at 8 and 12 weeks postoperation. Pathological analysis was performed with synovial tissue section and Osteoarthritis Research Society International histopathology grading and staging scores were determined. The quercetin treated group showed higher SOD and TIMP-1 expressions but lower MMP-13 expression than untreated OA group in the serum, synovial fluid and synovial tissues (p < .05). There was no significant difference in the SOD, MMP-13 and TIMP-1 expressions between the quercetin-treated and celecoxib-treated groups. The MMP-13/TIMP-1 ratio of the quercetin treated group was significantly lower than that of the untreated OA group (p < .05). Quercetin can up-regulate SOD and TIMP-1, down-regulate MMP-13, and improve the degeneration of OA through weakening the oxidative stress responses and inhibiting the degradation of cartilage extracellular matrix.

Clofoctol and sorafenib inhibit prostate cancer growth via synergistic induction of endoplasmic reticulum stress and UPR pathways

Background/Purpose

Prostate cancer is a major burden on public health and a major cause of morbidity and mortality among men worldwide. Drug combination therapy is known as a powerful tool for the treatment of cancer. The aim of this study is to evaluate the synergistic inhibitory mechanisms of clofoctol and sorafenib in the treatment of prostate cancer. However, the molecular mechanisms of this phenomenon have not been illuminated clearly. In this study, we investigated the anti-tumor effects of clofoctol in combination with sorafenib in vitro and in vivo.

Methods

The activity and mechanism of clofoctol in combination with sorafenib were examined in PC-3cells. mRNA and protein expression of key players in the ER stress pathway were detected with RT-PCR and Western blotting. Cell viability was estimated by CCK-8 assay or Alamar blue assay, and apoptosis and cell cycle were monitored and measured by flow cytometry. PC-3 cells were inoculated subcutaneously in male BALB/c nude mice. The therapeutic regimen was initiated when the tumor began showing signs of growth and treatment continued for 5 weeks.

Results

Our data indicate that clofototol and sorafenib induce cell death through synergistic induction of endoplasmic reticulum (ER) stress, resulting in activation of the unfolded protein response (UPR). Combination therapy with clofoctol and sorafenib induced an upregulation of markers of all three ER stress pathways: PERK, IRE1 and ATF6. In addition, combination therapy with clofoctol and sorafenib markedly inhibited the growth of prostate cancer xenograft tumors, compared with clofoctol or sorafenib alone.

Conclusion

The combination of clofoctol and sorafenib can serve as a novel clinical treatment regimen, potentially enhancing antitumor efficacy in prostate cancer and decreasing the dose and adverse effects of either clofoctol or sorafenib alone. These results lay the foundation for subsequent research on this novel therapeutic regimen in human prostate cancer.

Manuka honey synergistically enhances the chemopreventive effect of 5-fluorouracil on human colon cancer cells by inducing oxidative stress and apoptosis, altering metabolic phenotypes and suppressing metastasis ability

The development of chemo-sensitizers is urgently needed to overcome 5-fluorouracil (5-FU) therapeutic resistance and adverse toxicity in colorectal cancer. This work aims to evaluate the synergic effects of 5-FU and Manuka honey (MH), a rich source of bioactive compounds, in enhancing the anticancer effects of this drug on human colon cancer HCT-116 and LoVo cells. Compared to 5-FU alone, MH synergistically enhanced the chemotherapeutic effects of 5-FU, by reducing cell proliferation through the suppression of EGFR, HER2, p-Akt and p-mTOR expression, and promoting apoptosis by the modulation pro-apoptotic (p53, Bax, Cyto c, FasL caspase-3, -8, -9 and cleave-PARP) and anti-apoptotic (Bcl-2) markers. The activations of p-p38MAPK and p-Erk1/2 pathways and ROS production were also involved in this process. Downregulation of transcription factor (NF-κB and Nrf2) and antioxidant enzyme activity (SOD, catalase, glutathione peroxidase and glutathione reductase) and expression (SOD, catalase and HO-1) were more evident after the combined treatment, leading to more cell death by oxidative stress. Moreover, additive effects were also observed by increasing lipid and protein oxidation and arresting cell cycle. All the parameters of mitochondrial respiration and glycolysis function decreased and both cells entered the quiescent stage after the combined treatments. MH also influenced the anti-metastasis effects of 5-FU by decreasing migration ability, suppressing the expression of MMP-2, MMP-9 and increasing N-cadherin and E-cadherin. In conclusion, MH could be a useful preventive or adjuvant agent in the treatment of colorectal cancer with 5-FU.

Administration of antioxidants in cancer: debate of the decade

Several randomized clinical trials have divulged that administration of antioxidants during chemotherapy decreases the effectiveness of treatment. Hence, the characteristic feature of this article is extensive assessment of putative benefits and potential risks of natural and synthetic antioxidant supplementation, administered with chemotherapy, based upon the available preclinical and clinical data. After analyzing mixed results, it was concluded that current FDA guidelines should be followed before supplementing antioxidants during cytotoxic treatment. Nevertheless, contradictory experimental animal models opposing human clinical trials discourage the concurrent administration of antioxidants ostensibly owing to the possibility of tumor protection and reduced survival.

Enhancing the anti-ovarian cancer activity of quercetin using a self-assembling micelle and thermosensitive hydrogel drug delivery system

Ovarian cancer, as one of the killers that threaten women’s health, has been studied extensively. As a natural bioflavonoid with prospective effects, quercetin is highly recognized for its anti-cancer applications. However, one of the major challenges that quercetin faces is its poor water solubility, instability in physiological media, and subsequent poor bioavailability. Thus, optimizing the ideal drug delivery options is necessary to facilitate the harnessing of the maximum benefits from quercetin. In this study, a quercetin-loaded thermosensitive injectable hydrogel system (Qu-M–hydrogel composites) was constructed based on nanotechnology. Quercetin was encapsulated into MPEG-PCL (with a high drug loading of 7% and minor particle size of 32 nm) and then added into the blank thermosensitive hydrogel Pluronic F-127. The Qu-M–hydrogel composites showed a much slower release than Qu-M in vivo. Moreover, the cytotoxicity, apoptosis induction, and anti-tumor effects of the Qu-M–hydrogel composites on the abdominal SKOV-3 ovarian cancer mouse models were investigated in vivo. Compared with other groups, the Qu-M–hydrogel composites exhibited improved apoptosis induction and cell growth inhibition effects and in vivo trials showed a better balance between the anti-tumor efficacy in the Qu-M–hydrogel composite group than in other groups at an equal drug dose. In conclusion, the prepared Qu-M–hydrogel composites enhanced the anti-tumor activity by providing a high local quercetin concentration, sustained and stable drug release, extended drug retention inside the tumor, and low toxicity to normal tissues. The Qu-M–hydrogel composites might have great potential for clinical application in anti-ovarian cancer activity.

In this study, a quercetin-loaded thermosensitive injectable hydrogel system (Qu-M–hydrogel composites) was constructed based on nanotechnology.

FAM19A5, a brain-specific chemokine, inhibits RANKL-induced osteoclast formation through formyl peptide receptor 2

Osteoclasts can be differentiated from bone marrow-derived macrophages (BMDM). They play a key role in bone resorption. Identifying novel molecules that can regulate osteoclastogenesis has been an important issue. In this study, we found that FAM19A5, a neurokine or brain-specific chemokine, strongly stimulated mouse BMDM, resulting in chemotactic migration and inhibition of RANKL-induced osteoclastogenesis. Expression levels of osteoclast-related genes such as RANK, TRAF6, OSCAR, TRAP, Blimp1, c-fos, and NFATc1 were markedly decreased by FAM19A5. However, negative regulators of osteoclastogenesis such as MafB and IRF-8 were upregulated by FAM19A5. FAM19A5 also downregulated expression levels of RANKL-induced fusogenic genes such as OC-STAMP, DC-STAMP, and Atp6v0d2. FAM19A5-induced inhibitory effect on osteoclastogenesis was significantly reversed by a formyl peptide receptor (FPR) 2 antagonist WRW4 or by FPR2-deficiency, suggesting a crucial role of FPR2 in the regulation of osteoclastogenesis. Collectively, our results suggest that FAM19A5 and its target receptor FPR2 can act as novel endogenous ligand/receptor to negatively regulate osteoclastogenesis. They might be regarded as potential targets to control osteoclast formation and bone disorders.

Dietary polyphenols influence antimetabolite agents: methotrexate, 6-mercaptopurine and 5-fluorouracil in leukemia cell lines

Polyphenols have been previously shown to sensitize leukemia cell lines to topoisomerase inhibitors. Here, we assess the effects of five polyphenols when used alone and in combination with antimetabolites: methotrexate, 6-mercaptopurine and 5-fluorouracil; in lymphoid and myeloid leukemia cells lines, and non-tumor control cells. The effects of combined treatments were investigated on ATP and glutathione levels, cell-cycle progression, DNA damage and apoptosis.

Polyphenols antagonized methotrexate and 6-mercaptopurine induced cell-cycle arrest and apoptosis in most leukemia cell lines. This was associated with reduced DNA damage and increased glutathione levels, greater than that seen following individual treatments alone.

In contrast, 5-fluorouracil when combined with quercetin, apigenin and rhein caused synergistic decrease in ATP levels, induction of cell-cycle arrest and apoptosis in some leukemia cell lines. However, antagonistic effects were observed when 5-fluorouracil was combined with rhein and cis-stilbene in myeloid cell lines. The effects were dependant on polyphenol type and chemotherapy agent investigated, and cell type treated. Interestingly treatment of non-tumor control cells with polyphenols protected cells from antimetabolite treatments.

This suggests that polyphenols modulate the action of antimetabolite agents; more importantly they antagonized methotrexate and 6-mercaptopurine actions, thus suggesting the requirement of polyphenol-exclusion during their use.

The role of quercetin and vitamin C in Nrf2-dependent oxidative stress production in breast cancer cells

The balance between the production and elimination of reactive oxygen species (ROS) is essential in determining whether cells survive or undergo apoptosis. Nuclear factor erythroid 2-related factor 2 (Nrf2) may act as a sensor for electrophilic stress, thus regulating the intracellular antioxidant response. The present study investigated the role of vitamin C (VC) and quercetin (Q) in the induction of Nrf2-mediated oxidative stress in cancer cells. An MTT assay was conducted to examine the anti-proliferative effects of VC and Q. Reverse transcription-quantitative polymerase chain reaction and western blot analysis were performed to determine the messenger RNA (mRNA) and protein expression of Nrf2, respectively. The activity of nicotinamide adenine dinucleotide phosphate dehydrogenase quinone 1, heme oxygenase 1, glutathione peroxidase, glutathione reductase and reduced glutathione were measured by spectrophotometric analysis. Intracellular generation of ROS was determined using 2'-7'-dichlorodihydrofluorescein diacetate fluorescent probes. The results demonstrated that the cytotoxicity (50% inhibitory concentration) of VC and Q were 271.6-480.1 and 155.1-232.9 µM, respectively. Additionally, there was a significant decrease in the expression of Nrf2 mRNA and protein levels following the treatment of breast cancer cells with VC and Q (P=0.024). Following treatment with VC and Q, the nuclear/cytosolic Nrf2 ratio was reduced by 1.7-fold in MDA-MB 231 cells, 2-fold in MDA-MB 468 cells, 1.4-fold in MCF-7 cells and 1.2 fold in A549 cells. Sequential treatment with VC and Q decreased endogenous production of ROS in a dose-dependent manner (P=0.027). The results of the current study suggest that VC and Q treatment may be developed as an adjuvant for patients with cancer and overexpression of Nrf2.

Quercetin as an Emerging Anti-Melanoma Agent: A Four-Focus Area Therapeutic Development Strategy

Replacing current refractory treatments for melanoma with new prevention and therapeutic approaches is crucial in order to successfully treat this aggressive cancer form. Melanoma develops from neural crest cells, which express tyrosinase – a key enzyme in the pigmentation pathway. The tyrosinase enzyme is highly active in melanoma cells and metabolizes polyphenolic compounds; tyrosinase expression thus makes feasible a target for polyphenol-based therapies. For example, quercetin (3,3′,4′,5,7-pentahydroxyflavone) is a highly ubiquitous and well-classified dietary polyphenol found in various fruits, vegetables, and other plant products including onions, broccoli, kale, oranges, blueberries, apples, and tea. Quercetin has demonstrated antiproliferative and proapoptotic activity in various cancer cell types. Quercetin is readily metabolized by tyrosinase into various compounds that promote anticancer activity; additionally, given that tyrosinase expression increases during tumorigenesis, and its activity is associated with pigmentation changes in both early- and late-stage melanocytic lesions, it suggests that quercetin can be used to target melanoma. In this review, we explore the potential of quercetin as an anti-melanoma agent utilizing and extrapolating on evidence from previous in vitro studies in various human malignant cell lines and propose a “four-focus area strategy” to develop quercetin as a targeted anti-melanoma compound for use as either a preventative or therapeutic agent. The four areas of focus include utilizing quercetin to (i) modulate cellular bioreduction potential and associated signaling cascades, (ii) affect transcription of relevant genes, (iii) regulate epigenetic processes, and (iv) develop effective combination therapies and delivery modalities/protocols. In general, quercetin could be used to exploit tyrosinase activity to prevent, and/or treat, melanoma with minimal additional side effects.

Bioactive effects of quercetin in the central nervous system: Focusing on the mechanisms of actions

Quercetin, a ubiquitous flavonoid that is widely distributed in plants is classified as a cognitive enhancer in traditional and oriental medicine. The protective effects of quercetin for the treatment of neurodegenerative disorders and cerebrovascular diseases have been demonstrated in both in vitro and in vivo studies. The free radical scavenging activity of quercetin has been well-documented, wherein quercetin has been observed to exhibit protective effects against oxidative stress mediated neuronal damage by modulating the expression of NRF-2 dependent antioxidant responsive elements, and attenuation of neuroinflammation by suppressing NF-κB signal transducer and activator of transcription-1 (STAT-1). Several in vitro and in vivo studies have also shown that quercetin destabilizes and enhances the clearance of abnormal protein such as beta- amyloid peptide and hyperphosphorlyated tau, the key pathological hallmarks of Alzheimer's disease. Quercetin enhances neurogenesis and neuronal longevity by modulating a broad number of kinase signaling cascades such as phophoinositide 3- kinase (P13-kinase), AKT/PKB tyrosine kinase and Protein kinase C (PKC). Quercetin has also been well reported for its ability to reverse cognitive impairment and memory enhancement during aging. The current review focuses on summarizing the recent findings on the neuroprotective effect of quercetin, its mechanism of action and its possible roles in the prevention of neurological disorders.

Antioxidant Intake and Antitumor Therapy: Toward Nutritional Recommendations for Optimal Results

The role of the induction of oxidative stress as the mechanism of action of many antitumor drugs is acquiring an increasing interest. In such cases, the antitumor therapy success may be conditioned by the antioxidants present in our own body, which can be synthesized de novo (endogenous) or incorporated through the diet and nutritional supplements (exogenous). In this paper, we have reviewed different aspects of antioxidants, including their classification, natural sources, importance in diet, consumption of nutritional supplements, and the impact of antioxidants on health. Moreover, we have focused especially on the study of the interaction between antioxidants and antitumor therapy, considering both radiotherapy and chemotherapy. In this regard, we found that the convenience of administration of antioxidants during cancer treatment still remains a very controversial issue. In general terms, antioxidants could promote or suppress the effectiveness of antitumor treatment and even protect healthy tissues against damage induced by oxidative stress. The effects may depend on many factors discussed in the paper. These factors should be taken into consideration in order to achieve precise nutritional recommendations for patients. The evidence at the moment suggests that the supplementation or restriction of exogenous antioxidants during cancer treatment, as appropriate, could contribute to improving its efficiency.

Polyphenols as Modulator of Oxidative Stress in Cancer Disease: New Therapeutic Strategies

Cancer onset and progression have been linked to oxidative stress by increasing DNA mutations or inducing DNA damage, genome instability, and cell proliferation and therefore antioxidant agents could interfere with carcinogenesis. It is well known that conventional radio-/chemotherapies influence tumour outcome through ROS modulation. Since these antitumour treatments have important side effects, the challenge is to develop new anticancer therapeutic strategies more effective and less toxic for patients. To this purpose, many natural polyphenols have emerged as very promising anticancer bioactive compounds. Beside their well-known antioxidant activities, several polyphenols target epigenetic processes involved in cancer development through the modulation of oxidative stress. An alternative strategy to the cytotoxic treatment is an approach leading to cytostasis through the induction of therapy-induced senescence. Many anticancer polyphenols cause cellular growth arrest through the induction of a ROS-dependent premature senescence and are considered promising antitumour therapeutic tools. Furthermore, one of the most innovative and interesting topics is the evaluation of efficacy of prooxidant therapies on cancer stem cells (CSCs). Several ROS inducers-polyphenols can impact CSCs metabolisms and self-renewal related pathways. Natural polyphenol roles, mainly in chemoprevention and cancer therapies, are described and discussed in the light of the current literature data.

Serum amyloid A inhibits RANKL-induced osteoclast formation

When mouse bone marrow-derived macrophages were stimulated with serum amyloid A (SAA), which is a major acute-phase protein, there was strong inhibition of osteoclast formation induced by the receptor activator of nuclear factor kappaB ligand. SAA not only markedly blocked the expression of several osteoclast-associated genes (TNF receptor-associated factor 6 and osteoclast-associated receptor) but also strongly induced the expression of negative regulators (MafB and interferon regulatory factor 8). Moreover, SAA decreased c-fms expression on the cell surface via shedding of the c-fms extracellular domain. SAA also restrained the fusion of osteoclast precursors by blocking intracellular ATP release. This inhibitory response of SAA is not mediated by the well-known SAA receptors (formyl peptide receptor 2, Toll-like receptor 2 (TLR2) or TLR4). These findings provide insight into a novel inhibitory role of SAA in osteoclastogenesis and suggest that SAA is an important endogenous modulator that regulates bone homeostasis.