The flavonoid quercetin induces cell cycle arrest and mitochondria-mediated apoptosis in human cervical cancer (HeLa) cells through p53 induction and NF-κB inhibition

Molecular mechanisms of action of quercetin in cancer: recent advances

In the last few decades, the scientific community has discovered an immense potential of natural compounds in the treatment of dreadful diseases such as cancer. Besides the availability of a variety of natural bioactive molecules, efficacious cancer therapy still needs to be developed. So, to design an efficacious cancer treatment strategy, it is essential to understand the interactions of natural molecules with their respective cellular targets. Quercetin (Quer) is a naturally occurring flavonol present in many commonly consumed food items. It governs numerous intracellular targets, including the proteins involved in apoptosis, cell cycle, detoxification, antioxidant replication, and angiogenesis. The weight of available synergistic studies vigorously fortifies the utilization of Quer as a chemoprevention drug. This extensive review covers various therapeutic interactions of Quer with their recognized cellular targets involved in cancer treatment.

Anti-inflammatory and Antioxidant Effects of Flavonoid-Rich Fraction of Bergamot Juice (BJe) in a Mouse Model of Intestinal Ischemia/Reperfusion Injury

The flavonoid-rich fraction of bergamot juice (BJe) has demonstrated anti-inflammatory and antioxidant activities. The aim of work was to test the beneficial effects of BJe on the modulation of the ileum inflammation caused by intestinal ischemia/reperfusion (I/R) injury in mice. To understand the cellular mechanisms by which BJe may decrease the development of intestinal I/R injury, we have evaluated the activation of signaling transduction pathways that can be induced by reactive oxygen species production. Superior mesenteric artery and celiac trunk were occluded for 30 min and reperfused for 1 h. The animals were sacrificed after 1 h of reperfusion, for both histological and molecular examinations of the ileum tissue. The experimental results demonstrated that BJe was able to reduce histological damage, cytokines production, adhesion molecules expression, neutrophil infiltration and oxidative stress by a mechanism involved both NF-κB and MAP kinases pathways. This study indicates that BJe could represent a new treatment against inflammatory events of intestinal I/R injury.

Flow Cytometric Method for the Detection of Flavonoids in Cell Lines

Here, we describe an easy-to-use flow cytometric method using diphenylboric acid 2-amino ethyl ester (DPBA) stain for the detection of flavonoids in cells from human/animal origin. Flavonoid bioavailability and bioactivity depend on structure, conjugation and the cell type to which they are presented. We have studied cellular uptake of five flavonoids with different structures and conjugation forms. First, parameters including fixation method, technical and batch variability, and concentration were optimized. Second, uptake of two aglycones—quercetin and hesperetin—and their corresponding glycosides—rutin and hesperidin—in Caco-2 cells was compared. Third, the aglycone quercetin, glycoside rutin, and glucuronide baicalin were added to the Caco-2, HepG2, and CHO-K1 cell lines at 1, 10, and 20 µM concentrations and cellular uptake was measured after 1, 4, and 7 h. We conclude that quercetin was taken up by cells in a dose-dependent way, and that HepG2 cells had the highest uptake factors, followed by CHO-K1 and Caco-2 cells. Confocal microscopy showed cell type–dependent localization of quercetin in the cell membrane and cytoplasm. No uptake of flavonoid glycosides was detected. This flow cytometric method can be used for future research unravelling mechanisms behind flavonoid bioactivity in health and disease at the cellular level.

Targeted delivery of quercetin loaded mesoporous silica nanoparticles to the breast cancer cells

BACKGROUND

Mesoporous silica nanoparticles (MSNs) have been promising vehicles for drug delivery. Quercetin (Q), a natural flavonoid, has been reported to have many useful effects. However, poor water solubility as well as less bioavailability has confined its use as a suitable anti-cancer drug. Therefore, profound approach is required to overcome these drawbacks.

METHODS

We have synthesized folic acid (FA) armed mesoporous silica nanoparticles (MSN-FA-Q) loaded with quercetin and then characterized it by DLS, SEM, TEM and FTIR. MTT, confocal microscopy, flow cytometry, scratch assay and immunoblotting were employed to assess the cell viability, cellular uptake, cell cycle arrest, apoptosis, wound healing and the expression levels of different signalling molecules in breast adenocarcinoma cells. Nanoparticle distribution was investigated by using ex vivo optical imaging and CAM assay was employed to assess tumor regression.

RESULTS

MSN-FA-Q facilitates higher cellular uptake and allows more drug bioavailability to the breast cancer cells with over-expressed folate receptors. Our experimental results suggest that the newly synthesized MSN-FA-Q nanostructure caused cell cycle arrest and apoptosis in breast cancer cells through the regulation of Akt & Bax signalling pathways. Besides, we also observed that MSN-FA-Q has a concurrent anti-migratory role as well.

CONCLUSION

This uniquely engineered quercetin loaded mesoporous silica nanoparticle ensures a targeted delivery with enhanced bioavailability.

GENERAL SIGNIFICANCE

Effective targeted therapeutic strategy against breast cancer cells.

Investigating core genetic-and-epigenetic cell cycle networks for stemness and carcinogenic mechanisms, and cancer drug design using big database mining and genome-wide next-generation sequencing data

Recent studies have demonstrated that cell cycle plays a central role in development and carcinogenesis. Thus, the use of big databases and genome-wide high-throughput data to unravel the genetic and epigenetic mechanisms underlying cell cycle progression in stem cells and cancer cells is a matter of considerable interest.

Real genetic-and-epigenetic cell cycle networks (GECNs) of embryonic stem cells (ESCs) and HeLa cancer cells were constructed by applying system modeling, system identification, and big database mining to genome-wide next-generation sequencing data. Real GECNs were then reduced to core GECNs of HeLa cells and ESCs by applying principal genome-wide network projection. In this study, we investigated potential carcinogenic and stemness mechanisms for systems cancer drug design by identifying common core and specific GECNs between HeLa cells and ESCs. Integrating drug database information with the specific GECNs of HeLa cells could lead to identification of multiple drugs for cervical cancer treatment with minimal side-effects on the genes in the common core. We found that dysregulation of miR-29C, miR-34A, miR-98, and miR-215; and methylation of ANKRD1, ARID5B, CDCA2, PIF1, STAMBPL1, TROAP, ZNF165, and HIST1H2AJ in HeLa cells could result in cell proliferation and anti-apoptosis through NFκB, TGF-β, and PI3K pathways. We also identified 3 drugs, methotrexate, quercetin, and mimosine, which repressed the activated cell cycle genes, ARID5B, STK17B, and CCL2, in HeLa cells with minimal side-effects.

Anti-Breast Cancer Potential of Quercetin via the Akt/AMPK/Mammalian Target of Rapamycin (mTOR) Signaling Cascade

The Akt/adenosine monophosphate protein kinase (AMPK)/mammalian target of rapamycin (mTOR) pathway has emerged as a critical signaling nexus for regulating cellular metabolism, energy homeostasis, and cell growth. Thus, dysregulation of this pathway contributes to the development of metabolic disorders such as obesity, type 2diabetes, and cancer. We previously reported that a combination of grape polyphenols (resveratrol, quercetin and catechin: RQC), at equimolar concentrations, reduces breast cancer (BC) growth and metastasis in nude mice, and inhibits Akt and mTOR activities and activates AMPK, an endogenous inhibitor of mTOR, in metastatic BC cells. The objective of the present study was to determine the contribution of individual polyphenols to the effect of combined RQC on mTOR signaling. Metastatic BC cells were treated with RQC individually or in combination, at various concentrations, and the activities (phosphorylation) of AMPK, Akt, and the mTOR downstream effectors, p70S6 kinase (p70S6K) and 4E binding protein (4EBP1), were determined by Western blot. Results show that quercetin was the most effective compound for Akt/mTOR inhibition. Treatment with quercetin at 15μM had a similar effect as the RQC combination in the inhibition of BC cell proliferation, apoptosis, and migration. However, cell cycle analysis showed that the RQC treatment arrested BC cells in the G1 phase, while quercetin arrested the cell cycle in G2/M. In vivo experiments, using SCID mice with implanted tumors from metastatic BC cells, demonstrated that administration of quercetin at 15mg/kg body weight resulted in a ~70% reduction in tumor growth. In conclusion, quercetin appears to be a viable grape polyphenol for future development as an anti BC therapeutic.

Quercetin reduces cyclin D1 activity and induces G1 phase arrest in HepG2 cells

Quercetin is able to inhibit proliferation of malignant tumor cells; however, the exact mechanism involved in this biological process remains unclear. The current study utilized a quantitative proteomic analysis to explore the antitumor mechanisms of quercetin. The leucine of HepG2 cells treated with quercetin was labeled as d3 by stable isotope labeling by amino acids in cell culture (SILAC). The isotope peaks of control HepG2 cells were compared with the d3-labeled HepG2 cells by mass spectrometry (MS) to identify significantly altered proteins. Reverse transcription-polymerase chain reaction (RT-PCR) and western blot analyses were subsequently employed to verify the results of the MS analysis. A flow cytometry assay was designed to observe the influence of various quercetin treatment concentrations on the cell cycle distribution of HepG2 cells. The results indicated that quercetin is able to substantially inhibit proliferation of HepG2 cells and induce an obvious morphological alteration of cells. According to the MS results, the 70 credibly-changed proteins that were identified may play important roles in multiple cellular processes, including protein synthesis, signaling, cytoskeletal processes and metabolism. Among these functional proteins, the expression of cyclin D1 (CCND1) was found to be significantly decreased. RT-PCR and western blot analyses verified the SILAC-MS results of decreased CCND1 expression. In summary, flow cytometry revealed that quercetin is able to induce G1 phase arrest in HepG2 cells. Based on the aforementioned observations, it is suggested that quercetin exerts antitumor activity in HepG2 cells through multiple pathways, including interfering with CCND1 gene expression to disrupt the cell cycle and proliferation of HepG2 cells. In the future, we aim to explore this effect in vivo.

Quercetin Impacts Expression of Metabolism- and Obesity-Associated Genes in SGBS Adipocytes

Obesity is characterized by the rapid expansion of visceral adipose tissue, resulting in a hypoxic environment in adipose tissue which leads to a profound change of gene expression in adipocytes. As a consequence, there is a dysregulation of metabolism and adipokine secretion in adipose tissue leading to the development of systemic inflammation and finally resulting in the onset of metabolic diseases. The flavonoid quercetin as well as other secondary plant metabolites also referred to as phytochemicals have anti-oxidant, anti-inflammatory, and anti-diabetic effects known to be protective in view of obesity-related-diseases. Nevertheless, its underlying molecular mechanism is still obscure and thus the focus of this study was to explore the influence of quercetin on human SGBS (Simpson Golabi Behmel Syndrome) adipocytes’ gene expression. We revealed for the first time that quercetin significantly changed expression of adipokine (Angptl4, adipsin, irisin and PAI-1) and glycolysis-involved (ENO2, PFKP and PFKFB4) genes, and that this effect not only antagonized but in part even overcompensated the effect mediated by hypoxia in adipocytes. Thus, these results are explained by the recently proposed hypothesis that the protective effect of quercetin is not solely due to its free radical-scavenging activity but also to a direct effect on mitochondrial processes, and they demonstrate that quercetin might have the potential to counteract the development of obesity-associated complications.

Quercetin, a Natural Flavonoid Interacts with DNA, Arrests Cell Cycle and Causes Tumor Regression by Activating Mitochondrial Pathway of Apoptosis

Naturally occurring compounds are considered as attractive candidates for cancer treatment and prevention. Quercetin and ellagic acid are naturally occurring flavonoids abundantly seen in several fruits and vegetables. In the present study, we evaluate and compare antitumor efficacies of quercetin and ellagic acid in animal models and cancer cell lines in a comprehensive manner. We found that quercetin induced cytotoxicity in leukemic cells in a dose-dependent manner, while ellagic acid showed only limited toxicity. Besides leukemic cells, quercetin also induced cytotoxicity in breast cancer cells, however, its effect on normal cells was limited or none. Further, quercetin caused S phase arrest during cell cycle progression in tested cancer cells. Quercetin induced tumor regression in mice at a concentration 3-fold lower than ellagic acid. Importantly, administration of quercetin lead to ~5 fold increase in the life span in tumor bearing mice compared to that of untreated controls. Further, we found that quercetin interacts with DNA directly, and could be one of the mechanisms for inducing apoptosis in both, cancer cell lines and tumor tissues by activating the intrinsic pathway. Thus, our data suggests that quercetin can be further explored for its potential to be used in cancer therapeutics and combination therapy.

Simultaneous targeting of androgen receptor (AR) and MAPK-interacting kinases (MNKs) by novel retinamides inhibits growth of human prostate cancer cell lines

Androgen receptor (AR) and MNK activated eIF4E signaling promotes the development and progression of prostate cancer (PCa). In this study, we report that our Novel Retinamides (NRs) target both AR signaling and eIF4E translation in androgen sensitive and castration resistant PCa cells via enhancing AR and MNK degradation through ubiquitin-proteasome pathway. Dual blockade of AR and MNK initiated eIF4E activation by NRs in turn induced cell cycle arrest, apoptosis, and inhibited cell proliferation. NRs also inhibited cell migration and invasion in metastatic cells. Importantly, the inhibitory effects of NRs on AR signaling, eIF4E translation initiation and subsequent oncogenic program were more potent than that observed with clinically relevant retinoids, established MNK inhibitors, and the FDA approved PCa drugs. Our findings provide the first preclinical evidence that simultaneous inhibition of AR and eIF4E activation is a novel and efficacious therapeutic approach for PCa, and that NRs hold significant promise for treatment of advanced prostate cancer.

Cudrania tricuspidata Stem Extract Induces Apoptosis via the Extrinsic Pathway in SiHa Cervical Cancer Cells

The focus of this study is the anti-cancer effects of Cudrania tricuspidata stem (CTS) extract on cervical cancer cells. The effect of CTS on cell viability was investigated in HPV-positive cervical cancer cells and HaCaT human normal keratinocytes. CTS showed significant dose-dependent cytotoxic effects in cervical cancer cells. However, there was no cytotoxic effect of CTS on HaCaT keratinocytes at concentrations of 0.125-0.5 mg/mL. Based on this cytotoxic effect, we demonstrated that CTS induced apoptosis by down-regulating the E6 and E7 viral oncogenes. Apoptosis was detected by DAPI staining, annexin V-FITC/PI staining, cell cycle analysis, western blotting, RT-PCR, and JC-1 staining in SiHa cervical cancer cells. The mRNA expression levels of extrinsic pathway molecules such as Fas, death receptor 5 (DR5), and TNF-related apoptosis-inducing ligand (TRAIL) were increased by CTS. Furthermore, CTS treatment activated caspase-3/caspase-8 and cleavage of poly (ADP-ribose) polymerase (PARP). However, the mitochondrial membrane potential and expression levels of intrinsic pathway molecules such as Bcl-2, Bcl-xL, Bax, and cytochrome C were not modulated by CTS. Taken together, these results indicate that CTS induced apoptosis by activating the extrinsic pathway, but not the intrinsic pathway, in SiHa cervical cancer cells. These results suggest that CTS can be used as a modulating agent in cervical cancer.

New Approach for Treatment of Primary Liver Tumors: The Role of Quercetin

Hepatocellular carcinoma (HCC) is the most common primary liver tumor (PLT), with cholangiocarcinoma (CC) being the second most frequent. Glucose transporter 1 (GLUT-1) expression is increased in PLTs and therefore it is suggested as a therapeutic target. Flavonoids, like quercetin, are GLUT-1 competitive inhibitors and may be considered as potential therapeutic agents for PLTs. The objective of this study was evaluation of quercetin anticancer activity in three human HCC cell lines (HepG2, HuH7, and Hep3B2.1-7) and in a human CC cell line (TFK-1). The possible synergistic effect between quercetin and sorafenib, a nonspecific multikinase inhibitor used in clinical practice in patients with advanced HCC, was also evaluated. It was found that in all the cell lines, quercetin induced inhibition of the metabolic activity and cell death by apoptosis, followed by increase in BAX/BCL-2 ratio. Treatment with quercetin caused DNA damage in HepG2, Hep3B2.1-7, and TFK-1 cell lines. The effect of quercetin appears to be independent of P53. Incubation with quercetin induced an increase in GLUT-1 membrane expression and a consequent reduction in the cytoplasmic fraction, observed as a decrease in (18)F-FDG uptake, indicating a GLUT-1 competitive inhibition. The occurrence of synergy when sorafenib and quercetin were added simultaneously to HCC cell lines was noticed. Thus, the use of quercetin seems to be a promising approach for PLTs through GLUT-1 competitive inhibition.

Application of Bioactive Quercetin in Oncotherapy: From Nutrition to Nanomedicine

Phytochemicals as dietary constituents are being explored for their cancer preventive properties. Quercetin is a major constituent of various dietary products and recently its anti-cancer potential has been extensively explored, revealing its anti-proliferative effect on different cancer cell lines, both in vitro and in vivo. Quercetin is known to have modulatory effects on cell apoptosis, migration and growth via various signaling pathways. Though, quercetin possesses great medicinal value, its applications as a therapeutic drug are limited. Problems like low oral bioavailability and poor aqueous solubility make quercetin an unreliable candidate for therapeutic purposes. Additionally, the rapid gastrointestinal digestion of quercetin is also a major barrier for its clinical translation. Hence, to overcome these disadvantages quercetin-based nanoformulations are being considered in recent times. Nanoformulations of quercetin have shown promising results in its uptake by the epithelial system as well as enhanced delivery to the target site. Herein we have tried to summarize various methods utilized for nanofabrication of quercetin formulations and for stable and sustained delivery of quercetin. We have also highlighted the various desirable measures for its use as a promising onco-therapeutic agent.

Quercetin and the mitochondria: A mechanistic view

Quercetin is an important flavonoid that is ubiquitously present in the diet in a variety of fruits and vegetables. It has been traditionally viewed as a potent antioxidant and anti-inflammatory molecule. However, recent studies have suggested that quercetin may exert its beneficial effects independent of its free radical-scavenging properties. Attention has been placed on the effect of quercetin on an array of mitochondrial processes. Quercetin is now recognized as a phytochemical that can modulate pathways associated with mitochondrial biogenesis, mitochondrial membrane potential, oxidative respiration and ATP anabolism, intra-mitochondrial redox status, and subsequently, mitochondria-induced apoptosis. The present review evaluates recent evidence on the ability of quercetin to interact with the abovementioned pathways, and critically analyses how, such interactions can exert protection against mitochondrial damage in response to toxicity induced by several exogenously and endogenously-produced cellular stressors, and oxidative stress in particular.

Therapeutic Implications for Overcoming Radiation Resistance in Cancer Therapy

Ionizing radiation (IR), such as X-rays and gamma (γ)-rays, mediates various forms of cancer cell death such as apoptosis, necrosis, autophagy, mitotic catastrophe, and senescence. Among them, apoptosis and mitotic catastrophe are the main mechanisms of IR action. DNA damage and genomic instability contribute to IR-induced cancer cell death. Although IR therapy may be curative in a number of cancer types, the resistance of cancer cells to radiation remains a major therapeutic problem. In this review, we describe the morphological and molecular aspects of various IR-induced types of cell death. We also discuss cytogenetic variations representative of IR-induced DNA damage and genomic instability. Most importantly, we focus on several pathways and their associated marker proteins responsible for cancer resistance and its therapeutic implications in terms of cancer cell death of various types and characteristics. Finally, we propose radiation-sensitization strategies, such as the modification of fractionation, inflammation, and hypoxia and the combined treatment, that can counteract the resistance of tumors to IR.

Quercetin Mediates β-Catenin in Pancreatic Cancer Stem-Like Cells

OBJECTIVE

The aim of this study is to explore how quercetin interacts with pancreatic cancer stem-like cells and the mechanism underlying the effective quercetin-mediated suppression.

METHODS

A model of pancreatic cancer stem-like cells was generated by using a sphere formation culture system. A comparative analysis was performed between the parent cells and pancreatic cancer stem-like cells with a related treatment strategy focusing on cancer stem cell (CSC) properties and drug-resistance-related mechanisms in vitro.

RESULTS

Our data show that pancreatic cancer stem-like cells have greater resistance to gemcitabine and stronger CSC properties compared with the parent cells. In contrast to the pancreatic cancer stem-like cells, overexpression of β-catenin was observed in the parent cells. Quercetin suppressed proliferation, invasion and self-renewal capacity, and CSC surface markers expression, with alterations of β-catenin in pancreatic cancer stem-like cells. The combination of quercetin and gemcitabine can reduce tumor growth and decrease drug resistance in pancreatic cancer.

CONCLUSIONS

β-Catenin plays an important role in maintenance and progression of pancreatic cancer. Targeting β-catenin using quercetin combined with gemcitabine may be a treatment strategy to improve prognosis in patients with pancreatic cancer.

2',4'-dihydroxychalcone, a flavonoid isolated from Herba oxytropis, suppresses PC-3 human prostate cancer cell growth by induction of apoptosis

Natural products are a promising source for the development of novel cancer therapies, due to their potential effectiveness and low toxicity profiles. As a main component of Herba oxytropis, 2',4'-dihydroxychalcone (TFC) is known to demonstrate anti-tumor activity in vitro. In the present study, TFC was found to potently inhibit proliferation and induce apoptosis in PC-3 human prostate cancer cells in a dose-dependent manner. The results demonstrated that the induction of apoptosis is associated with cell cycle arrest at the G0/G1 phase and activation of caspase-3/-7. Additional mechanistic studies of two biomarkers, phosphatase and tensin homolog (PTEN) and cyclin-dependent kinase inhibitor 1B (p27^Kip1), in prostate cancer revealed that TFC treatment significantly upregulated the expression of PTEN and p27^Kip1. The findings of the present study indicate that TFC-induced apoptosis in PC-3 cells via upregulation of PTEN and p27^Kip1, which results in cell cycle arrest in G0/G1 phase, activation of caspase-3/-7 and induction of apoptosis. Therefore, TFC may be a potential compound for human prostate cancer therapy.

Critical role of NF-κB in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers, and in spite of intense efforts there are limited therapeutic options for patients with PDAC. PDACs harbor a high frequency of Kras mutations and other driver mutations that lead to altered signaling pathways and contribute to therapeutic resistance. Importantly, constitutive activation of nuclear factor κB (NF-κB) is frequently observed in PDAC. An increasing body of evidence suggests that both classical and non-classical NF-κB pathways play a crucial role in PDAC development and progression. In this review, we update the most recent advances regarding different aspects of NF-κB involvement in PDAC development and progression, emphasizing its potential as a therapeutic target and the need to discover pathway-specific cytosolic NF-κB regulators which could be used to design novel therapeutic strategies for PDAC.

MicroRNA-143 enhances chemosensitivity of Quercetin through autophagy inhibition via target GABARAPL1 in gastric cancer cells

MicroRNAs have emerged as fundamental regulators in gene expression through silencing gene expression at the post-transcriptional and translational levels. In this study, miR-143 expression and biological functions in AGS/MNK28 cell lines was investigated. Results indicated that the expression of miR-143 was significantly down-regulated in cancer tissues and in gastric cancer (GC) cell lines. Target prediction algorithms (Target Scan and miRanda) showed that GABARAPL1 was a potential target gene of miR-143. GABARAPL1, also regarded as autophagy-related protein 8 (Atg8) is a ubiquitin-like protein required for the formation of autophagosomal membranes. Then, several different assays were conducted to detect autophagy in AGS/MNK28 after transfected with miR-143. In the present study, miR-143 was firstly identified as a autophagy inhibitor in GC cells via targeting GABARAPL1. Quercetin is one of the most prominent dietary antioxidants in human diet and lately it is grabbing some serious attention as a potentially powerful cancer fighter. However, the effect of Quercetin was unexpected decreased in GC cells on account of the appearance of Quercetin-induced autophagy. Therefore, applicable autophagy inhibitors might enhance the chemosensitivity of Quercetin. Furthermore, the therapeutic response of Quercetin in the combination of miR-143 was evaluated by MTT, Hochest and western blot, results suggesting that the chemosensitivity of Quercetin was enhanced when in combination with miR-143 in AGS/MNK28 cells. In conclusion, we determined miR-143 as a potent inhibitor of autophagy via targeting GABARAPL1 and miR-143 could improve the efficacy of Quercetin though autophagy inhibition in GC cell lines, thus representing a novel potential therapeutic target for gastric cancer.

HAX-1 inhibits apoptosis in prostate cancer through the suppression of caspase-9 activation

HS1 associated protein X-1 (HAX-1), a substrate of Src family tyrosine kinases, plays a critical role in cell apoptosis. However, its functions in prostate cancer remains unclear. The present study explored the role and mechanism of HAX-1 in cancer cell apoptosis. The mRNA and protein levels of HAX-1 in the prostate cancer cell lines PC-3, VCaP and DU145 were assessed. Cell proliferation, apoptosis and caspase-9 activities were assessed in DU145 after HAX-1 siRNA treatment. The mRNA and protein levels of HAX-1 in prostate cancer cell lines PC-3, VCaP and DU145 were significantly higher than those in the primary prostate epithelial cells, and DU145 possess the highest mRNA and protein levels compared to PC-3 and VCaP. When HAX-1 was knocked down in DU145, cell proliferation was significantly decreased, accompanied by a decrease in Ki67 protein expression. Compared with the control and control siRNA groups, HAX-1 siRNA promoted cell apoptosis and caspase-9 activation in DU145. Furthermore, prostate cancer cells co-transfected with HAX-1 and caspase-9 promoted viability and reduced apoptosis. In contract, co-transfection of caspase-9 and HAX-1 siRNA suppressed the cell viability and enhanced apoptosis. In summary, the present study demonstrated that HAX-1 inhibits cell apoptosis through caspase-9 inactivation.

How Phytochemicals Prevent Chemical Carcinogens and/or Suppress Tumor Growth?

Phytochemicals are a powerful group of chemicals that are derived from natural resource, especially with plants origin. They have shown to exhibit chemoprevention and chemotherapeutic effects not only in cell lines and in animal models of cancer but also some of them are in the clinical trial phase I and II. Despite numerous reports of these phytochemical effects on cancer, an overview of the mechanisms of their action and their effects on various cellular and molecular functions important in the inhibition of cancer progression has been lacking. In this review, we attempt to catalogue various studies to examine the effect of phytochemicals in cancer initiation, promotion, signaling, and epigenetic changes. Because of the numerous studies in these topics, we only pointed out to some examples in each section.

Tuning cell adhesion by direct nanostructuring silicon into cell repulsive/adhesive patterns

Developing platforms that allow tuning cell functionality through incorporating physical, chemical, or mechanical cues onto the material surfaces is one of the key challenges in research in the field of biomaterials. In this respect, various approaches have been proposed and numerous structures have been developed on a variety of materials. Most of these approaches, however, demand a multistep process or post-chemical treatment. Therefore, a simple approach would be desirable to develop bio-functionalized platforms for effectively modulating cell adhesion and consequently programming cell functionality without requiring any chemical or biological surface treatment. This study introduces a versatile yet simple laser approach to structure silicon (Si) chips into cytophobic/cytophilic patterns in order to modulate cell adhesion and proliferation. These patterns are fabricated on platforms through direct laser processing of Si substrates, which renders a desired computer-generated configuration into patterns. We investigate the morphology, chemistry, and wettability of the platform surfaces. Subsequently, we study the functionality of the fabricated platforms on modulating cervical cancer cells (HeLa) behaviour. The results from in vitro studies suggest that the nanostructures efficiently repel HeLa cells and drive them to migrate onto untreated sites. The study of the morphology of the cells reveals that cells evade the cytophobic area by bending and changing direction. Additionally, cell patterning, cell directionality, cell channelling, and cell trapping are achieved by developing different platforms with specific patterns. The flexibility and controllability of this approach to effectively structure Si substrates to cell-repulsive and cell-adhesive patterns offer perceptible outlook for developing bio-functionalized platforms for a variety of biomedical devices. Moreover, this approach could pave the way for developing anti-cancer platforms that selectively repel cancer cells while favoring the adhesion of normal cells.

Characteristic features of cytotoxic activity of flavonoids on human cervical cancer cells

Cervical cancer is the most common gynecologic malignancy worldwide and development of new therapeutic strategies and anticancer agents is an urgent priority. Plants have remained an important source in the search for novel cytotoxic compounds and several polyphenolic flavonoids possess antitumor properties. In this review article, data about potential anticarcinogenic activity of common natural flavonoids on various human cervical cancer cell lines are compiled and analyzed showing perspectives for the use of these secondary metabolites in the treatment of cervical carcinoma as well as in the development of novel chemotherapeutic drugs. Such anticancer effects of flavonoids seem to differentially depend on the cellular type and origin of cervical carcinoma creating possibilities for specific targeting in the future. Besides the cytotoxic activity per se, several flavonoids can also contribute to the increase in efficacy of conventional therapies rendering tumor cells more sensitive to standard chemotherapeutics and irradiation. Although the current knowledge is still rather scarce and further studies are certainly needed, it is clear that natural flavonoids may have a great potential to benefit cervical cancer patients.

Streptozotocin Induced Neurotoxicity Involves Alzheimer's Related Pathological Markers: a Study on N2A Cells

Intracerebroventricular (icv) injection of streptozotocin (STZ) in rat brain causes prolonged impairment of brain energy metabolism and oxidative damage and leads to cognitive dysfunction; however, its mechanistic specific effects on neurons are not known. The present study was conducted to investigate the STZ-induced cellular and molecular alterations in mouse neuronal N2A cells. The N2A cells were treated with STZ (10, 50, 100, 1000 μM) for 48 h, and different assays were performed. STZ treatment caused significant decrease in cell viability, choline levels, increased acetylcholinesterase (AChE) activity, tau phosphorylation and amyloid aggregation. STZ treatment also led to low levels of glucose uptake, elevated mitochondrial stress, translocation of cytochrome c in cytosol, phosphatidylserine externalization, increased expression of caspase-3 and DNA damage. Co-treatment of clinically used drug donepezil (1 μM) offered significant protection against STZ induced neurotoxicity. Donepezil treatment significantly inhibited the STZ induced neurotoxicity, altered choline level, AChE activity, lowered glucose uptake and mitochondrial stress. However, the caspase-3 expression remains unaltered with co-treatment of donepezil. In conclusion, findings showed that STZ treated N2A cells exhibited the Alzheimer's disease (AD) related pathological markers which are attenuated with co-treatment of donepezil. Findings of the study suggested the potent use of STZ treated N2A cells as in vitro experimental test model to study the disease mechanism at cellular level.

Effect of quercetin against lindane induced alterations in the serum and hepatic tissue lipids in wistar rats

OBJECTIVE

To assess the effect of quercetin (flavonoid) against lindane induced alterations in lipid profile of wistar rats.

METHODS

Rats were administered orally with lindane (100 mg/kg body weight) and quercetin (10 mg/kg body weight) for 30 days. After the end of treatment period lipid profile was estimated in serum and tissue.

RESULTS

Elevated levels of serum cholesterol, triglycerides, low density lipoprotein (LDL), very Low Density Lipoprotein (VLDL) and tissue triglycerides, cholesterol with concomitant decrease in serum HDL and tissue phospholipids were decreased in lindane treated rats were found to be significantly decreased in the quercetin and lindane co-treated rats.

CONCLUSIONS

Our study suggests that quercetin has hypolipidemic effect and offers protection against lindane induced toxicity in liver by restoring the altered levels of lipids. The quercetin cotreatment along with lindane for 30 days reversed these biochemical alterations in lipids induced by lindane.

Synthesis and pharmacological evaluation of novel bisindole derivatives bearing oximes moiety: identification of novel proapoptotic agents

In an effort to develop potent anti-cancer chemopreventive agents, a novel series of bisindole derivatives bearing oxime moiety were synthesized. Structures of all compounds were characterized by NMR and HRMS. Anti-proliferative activities for all of these compounds were investigated by the method of MTT assay on 7 human cancer lines and the normal cell lines (HUVEC). Most of them showed a noteworthy anti-cancer activity in vitro, the half maximal inhibitory concentration (IC50) value is 4.31 μM of 4e against T24. The results from Hoechst 33258 and acridine orange/propidium iodide staining as well as annexinV-FITC assays provided evidence for an apoptotic cell death. The further mechanisms of compound 4e-induced apoptosis in T24 cells demonstrated that compound 4e induced the productions of ROS, and altered anti- and pro-apoptotic proteins, leading to mitochondrial dysfunction and activations of caspase-9 and caspase-3 for causing cell apoptosis. Moreover, the cell cycle analysis and western-blot analysis indicated that compound 4e effectively arrested T24 cells in G1 stage and possibly has an effect on cell cycle regulatory proteins particularly cyclin D1.

Quercetin regresses Dalton's lymphoma growth via suppression of PI3K/AKT signaling leading to upregulation of p53 and decrease in energy metabolism

Various oncogenes are associated with deregulation in cell proliferation, apoptosis, and cell survival, which ultimately cause cancerous growth. Phosphatidylinositol 3-kinase (PI3K) mediated signaling plays a key role in malignant transformation. Cell proliferation and cell survival of tumor cell are induced by hyper activation of PI3K, AKT1, glycolytic enzyme LDH-A, and inactivation of tumor suppressor gene p53. Dietary flavonoids such as quercetin are considered a powerful modulator of different cellular signaling pathways. The present study is focused on the role of quercetin on regulation of PI3K/AKT pathways in Dalton's lymphoma mice. Effect of quercetin was analyzed in ascite cells in terms of cell viability, glycolytic metabolism as well as expression, and level of PI3K (regulatory and catalytic subunit), AKT1, and p53 using standard methods. Results reflect hyperactivation of PI3K signaling in ascite cells of Dalton's lymphoma mice, leading to activation of AKT1 and inactivation of p53. Quercetin modulates the pathway toward suppression of lymphoma. Glycolytic metabolism was also downregulated by quercetin. Its tumor suppressor activity was confirmed by morphological parameters and longevity of mice. The findings suggest that quercetin may contribute to lymphoma prevention by downregulating PI3K-AKT1-p53 pathway as well as by glycolytic metabolism.

Curcumin improves the paclitaxel-induced apoptosis of HPV-positive human cervical cancer cells via the NF-κB-p53-caspase-3 pathway

Paclitaxel, isolated from Taxus brevifolia, is considered to be an efficacious agent against a wide spectrum of human cancers, including human cervical cancer. However, dose-limiting toxicity and high cost limit its clinical application. Curcumin, a nontoxic food additive, has been reported to improve paclitaxel chemotherapy in mouse models of cervical cancer. However, the underlying mechanisms remain unclear. In this study, two human cervical cancer cell lines, CaSki [human papilloma virus (HPV)16-positive] and HeLa (HPV18-positive), were selected in which to investigate the effect of curcumin on the anticancer action of paclitaxel and further clarify the mechanisms. Flow cytometry and MTT analysis demonstrated that curcumin significantly promoted paclitaxel-induced apoptosis and cytotoxicity in the two cervical cell lines compared with that observed with paclitaxel alone (P<0.05). Reverse transcription-polymerase chain reaction indicated that the decline of HPV E6 and E7 gene expression induced by paclitaxel was also assisted by curcumin. The expression levels of p53 protein and cleaved caspase-3 were increased significantly in the curcumin plus paclitaxel-treated HeLa and CaSki cells compared with those in the cells treated with paclitaxel alone (P<0.01). Significant reductions in the levels of phosphorylation of IκBα and the p65-NF-κB subunit in CaSki cells treated with curcumin and paclitaxel were observed compared with those in cells treated with paclitaxel alone (P<0.05). This suggests that the combined effect of curcumin and paclitaxel was associated with the NF-κB-p53-caspase-3 pathway. In conclusion, curcumin has the ability to improve the paclitaxel-induced apoptosis of HPV-positive human cervical cancer cell lines via the NF-κB-p53-caspase-3 pathway. Curcumin in combination with paclitaxel may provide a superior therapeutic effect on human cervical cancer.

Adaptive cellular stress pathways as therapeutic targets of dietary phytochemicals: focus on the nervous system

During the past 5 decades, it has been widely promulgated that the chemicals in plants that are good for health act as direct scavengers of free radicals. Here we review evidence that favors a different hypothesis for the health benefits of plant consumption, namely, that some phytochemicals exert disease-preventive and therapeutic actions by engaging one or more adaptive cellular response pathways in cells. The evolutionary basis for the latter mechanism is grounded in the fact that plants produce natural antifeedant/noxious chemicals that discourage insects and other organisms from eating them. However, in the amounts typically consumed by humans, the phytochemicals activate one or more conserved adaptive cellular stress response pathways and thereby enhance the ability of cells to resist injury and disease. Examplesof such pathways include those involving the transcription factors nuclear factor erythroid 2-related factor 2, nuclear factor-κB, hypoxia-inducible factor 1α, peroxisome proliferator-activated receptor γ, and forkhead box subgroup O, as well as the production and action of trophic factors and hormones. Translational research to develop interventions that target these pathways may lead to new classes of therapeutic agents that act by stimulating adaptive stress response pathways to bolster endogenous defenses against tissue injury and disease. Because neurons are particularly sensitive to potentially noxious phytochemicals, we focus on the nervous system but also include findings from other cell types in which actions of phytochemicals on specific signal transduction pathways have been more thoroughly studied.

Signaling proteins and pathways affected by flavonoids in leukemia cells

Flavonoids are a class of plant secondary metabolites that are found ubiquitously in plants and in the human diet. Our objective is to investigate the antiproliferative effects of flavonoids (baicalein, luteolin, genistein, apigenin, scutellarin, galangin, chrysin, and naringenin) toward leukemia cells (HL-60, NB4, U937, K562, Jurkat) as well as the relationship between their antileukemic potencies and molecular structures. At the proteomic level, we evaluate the effects of different flavonoids on the expression levels of various proteins using Protein Pathway Array (PPA) technology. Our results showed a dose-dependent cytotoxicity of flavonoids toward various types of leukemia cells. The results of PPA illustrated that flavonoids, such as baicalein, genistein, and scutellarin affected different proteins in different leukemia cell lines. Cell cycle regulatory proteins, such as CDK4, CDK6, Cyclin D1, Cyclin B1, p-CDC2, and p-RB were affected in different leukemia cells. Furthermore, we found that baicalein suppresses CDK4 and activates p-ERK in most leukemia cells; genistein mainly affects CDK4, p-ERK, p-CDC2, while scutellarin dysregulated the proteins, cell division control protein 42, Notch4, and XIAP. Collectively, a wide variety of dysregulation of key signaling proteins related to apoptosis and cell-cycle regulation contributes to the antileukemic properties of these flavonoids.

Synthesis of chitosan-coated polyoxometalate nanoparticles against cancer and its metastasis

HeLa cells, before and after treatment with nanoparticles.

Anti-proliferative effects of quercetin and catechin metabolites

Dietary flavonoids have been associated with a lower incidence of some chronic diseases. However, the mechanisms behind the in vivo biological activity of flavonoids are still mostly unknown. Flavonoids are metabolized in the human body to conjugated forms (methylated, sulphated and glucuronidated derivatives) that should play a role in flavonoid activity. In this study, the anti-proliferative effects of conjugated metabolites of quercetin and (epi)catechin, major flavonoids in the diet, have been evaluated against three different cancer cell lines from breast (MCF-7), colon (Caco-2) and pancreas (BxPC-3) and one normal cell line of human foreskin fibroblasts (HFF-1), and compared with the effect of their unconjugated forms. Quercetin showed anti-proliferative activity on the three assayed cell models, whereas catechin and epicatechin were not active. Methylation on ring-B of quercetin decreased the anti-proliferative effects, especially when the methylation occurred in position 3' (isorhamnetin), although methylated metabolites still showed significant anti-proliferative activity. As to catechins, 4'-O-methyl-epicatechin and 3'-O-methyl-epicatechin were the only ones to show some activity on MCF-7 and BxPC-3 cell lines, respectively. Conjugation of quercetin with glucose or glucuronic acid eliminated the anti-proliferative effects of aglycones. Sulphated metabolites were also tested and found to be inactive in most of the explored cell lines, although quercetin-4'-O-sulphate and epicatechin-3'-O-sulphate still showed some anti-proliferative activity on MCF-7 and Caco-2 cells, respectively.

The anti-inflammatory and antioxidant effects of bergamot juice extract (BJe) in an experimental model of inflammatory bowel disease

BACKGROUND & AIMS

The beneficial properties of the flavonoid fraction of bergamot juice (BJe) have been raising interest and have been the subject of recent studies, considering the potentiality of its health promoting substances. Flavonoids have demonstrated radical-scavenging and anti-inflammatory activities. The aim of the present study was to examine the effects of BJe in mice subjected to experimental colitis.

METHODS

Colitis was induced in mice by intracolonic instillation of dinitrobenzene sulfonic acid (DNBS). BJe was administered daily orally (at 5, 10 and 20 mg/kg).

RESULTS

Four days after DNBS administration, colon nuclear factor NF-κB translocation and MAP kinase phospho-JNK activation were increased as well as cytokine production such as tumor necrosis factor (TNF)-α and interleukin (IL)-1β. Neutrophil infiltration, by myeloperoxidase (MPO) activity, in the mucosa was associated with up-regulation of adhesion molecules (ICAM-1 and P-selectin). Immunohistochemistry for nitrotyrosine and poly ADP-ribose (PAR) also showed an intense staining in the inflamed colon. Treatment with BJe decreased the appearance of diarrhea and body weight loss. This was associated with a reduction in colonic MPO activity. BJe reduced nuclear NF-κB translocation, p-JNK activation, the pro-inflammatory cytokines release, the appearance of nitrotyrosine and PAR in the colon and reduced the up-regulation of ICAM-1 and P-selectin. In addition, colon inflammation was also associated with apoptotic damage. Treatment with BJe caused a decrease of pro-apoptotic Bax expression and an increase of anti-apoptotic Bcl-2 expression.

CONCLUSIONS

The results of this study suggested that administration of BJe induced, partly specified, anti-inflammatory mechanisms, which potentially may be beneficial for the treatment of IBD in humans.

Mechanisms of hela cell apoptosis induced by abnormal Savda Munziq total phenolics combined with chemotherapeutic agents

OBJECTIVE

To investigate the effects of abnormal Savda Munziq (ASMq) total phenolics combined with cisplatin and docetaxel on the Hela cell growth.

METHODS

In vivo cultured Hela cells were treated with cisplatin, docetaxel, total phenolics, cisplatin+total phenolics or docetaxel+total phenolics. MTT was performed to assess inhibition of cell proliferation, flow cytometry to detect apoptosis, and semi-quantitative RT-PCR to test for survivin and Bcl-2 expression.

RESULTS

The total phenolics, cisplatin and docetaxel had significant inhibitory and apoptosis-promoting effects on Hela cells (P<0.05), with the early apoptotic rates of 12.8±0.70%, 18.9±3.79% and 15.8±3.8)%; the total phenolics, cisplatin and docetaxel significantly decreased the expression of Bcl-2 and survivin (all P<0.01), especially when used in combination.

CONCLUSION

ASMq total phenolics, combined with cisplatin and docetaxel, could promote the apoptosis of Hela cells possibly through reducing the expression of Bcl-2 and survivin.

Simultaneous determination of esculetin, quercetin-3-O-β-D-glucuronide, quercetin-3-O-β -D-glucuronopyranside methyl ester and quercetin in effective part of Polygonum Perfoliatum L. using high performace liquid chromatography

Objective:

In the present study, a high performance liquid chromatography (HPLC) coupled with photodiode array detection was developed for simultaneous quantitation of esculetin, quercetin-3-O-β-D-glucuronide, quercetin-3-O-β-D- glucuronopyranoside methyl ester and quercetin in Polygonum perfoliatum L.

Materials and Methods:

The chromatographic separations were performed on a reversed-phase C₁₈ column using a mobile phase composed of acetonitrile -0.5% aqueous acetic acid with gradient elution. The calibration curves for the analytes demonstrated good linearities within the investigated ranges. The satisfactory intra- and inter-day precision, repeatability and stability of the developed analytical method were shown in the method validation procedure. The recoveries of the established method ranged from 95.76 to 102.10% for all the analytes.

Results:

This proposed method was successfully applied for simultaneous quantification of the four compounds in effective part of Polygonum perfoliatum L. from different regions. Hierarchical clustering analysis (HCA) and principal components analysis (PCA) were performed to characterize and classify the samples based on the contents of the four compounds in Polygonum perfoliatum L.

Conclusion:

The established HPLC method combined with chemometric approaches was proven to be useful and efficient for quality control of Polygonum perfoliatum L.

Secoiridoid type of antiallergic substances in olive waste materials of three Japanese varieties of Olea europaea

2-Hydroxy-3-ethylidene-5-(methoxycarbonyl)-3,4-dihydro-2H-pyran-4-acetic acid 2-(3,4-dihydroxyphenyl)ethyl ester (3,4-DHPEA-EA) is a kind of secoiridoid first found in three Japanese olive pomaces: Mission, Lucca, and Manzanillo. These varieties showed high activity of 3,4-DHPEA-EA as an antiallergic active substance with IC50 at 33.5 ± 0.6 μg/mL. Because 3,4-DHPEA-EA was the most abundant among the active substances in the pomaces and the activity of 3,4-DHPEA-EA was greater than that of hydroxytyrosol and elenolic acid, 3,4-DHPEA-EA, which has the ester linkage of hydroxytyrosol and elenolic acid, should be essential for antiallergic activity. Although a trace amount (1.04 mg/kg) of luteolin in the pomace showed the highest antiallergic activity with IC50 at 0.752 ± 0.1 μg/mL, we concluded that the entire antiallergic effect derives from the abundance of 3,4-DHPEA-EA, especially in the green olive pomace of the Mission variety in October, which showed the highest level of 3,4-DHPEA-EA (5033 ± 118 mg/kg). Therefore, the Mission variety had the most effective antiallergy property.