Quercetin enhances the effects of 5-fluorouracil-mediated growth inhibition and apoptosis of esophageal cancer cells by inhibiting NF-κB

Flavonoids as promising anticancer therapeutics: Contemporary research, nanoantioxidant potential, and future scope

Flavonoids are natural polyphenolic compounds considered safe, pleiotropic, and readily available molecules. It is widely distributed in various food products such as fruits and vegetables and beverages such as green tea, wine, and coca-based products. Many studies have reported the anticancer potential of flavonoids against different types of cancers, including solid tumors. The chemopreventive effect of flavonoids is attributed to various mechanisms, including modulation of autophagy, induction of cell cycle arrest, apoptosis, and antioxidant defense. Despite of significant anticancer activity of flavonoids, their clinical translation is limited due to their poor biopharmaceutical attributes (such as low aqueous solubility, limited permeability across the biological membranes (intestinal and blood-brain barrier), and stability issue in biological systems). A nanoparticulate system is an approach that is widely utilized to improve the biopharmaceutical performance and therapeutic efficacy of phytopharmaceuticals. The present review discusses the significant anticancer potential of promising flavonoids in different cancers and the utilization of nanoparticulate systems to improve their nanoantioxidant activity further to enhance the anticancer activity of loaded promising flavonoids. Although, various plant-derived secondary metabolites including flavonoids have been recommended for treating cancer, further vigilant research is warranted to prove their translational values.

Exploring the Remarkable Chemotherapeutic Potential of Polyphenolic Antioxidants in Battling Various Forms of Cancer

Plant-derived compounds, specifically antioxidants, have played an important role in scavenging the free radicals present under diseased conditions. The persistent generation of free radicals in the body leads to inflammation and can result in even more severe diseases such as cancer. Notably, the antioxidant potential of various plant-derived compounds prevents and deregulates the formation of radicals by initiating their decomposition. There is a vast literature demonstrating antioxidant compounds' anti-inflammatory, anti-diabetic, and anti-cancer potential. This review describes the molecular mechanism of various flavonoids, such as quercetin, kaempferol, naringenin, epicatechin, and epicatechin gallate, against different cancers. Additionally, the pharmaceutical application of these flavonoids against different cancers using nanotechnologies such as polymeric, lipid-based nanoparticles (solid-lipid and liquid-lipid), liposomes, and metallic nanocarriers is addressed. Finally, combination therapies in which these flavonoids are employed along with other anti-cancer agents are described, indicating the effective therapies for the management of various malignancies.

Combination of Quercetin or/and siRNA-loaded DDAB-mPEG-PCL hybrid nanoparticles reverse resistance to Regorafenib in colon cancer cells

BACKGROUND

Colorectal cancer (CRC) is the second leading cause of cancer death. Although Regorafenib showed survival benefits in patients with CRC, reports imply the recurrence of malignant phenotype resulting from chemotherapy. Evidence demonstrated that a5β1 integrin plays an important role in the Regorafenib treatment, which, may be led to resistance. In this study, the effects of /siRNA or/ and Quercetin loaded DDAB-mPEG-PCLnanoparticles could reverse this resistance phenotype in colon cancer cells in vitro.

METHODS

Regorafenib-resistant Ls-180 colon cancer cell line was developed by long-term exposure to Regorafenib. Quercetin and Regorafenib were separately encapsulated into mPEG-PCL micelles through the nano-precipitation method and characterized by DLS. Optimized doses of Quercetin and Regorafenib were used for combination therapy of resistant cells followed cytotoxicity study using MTT. Gene expression levels of the β1 subunit of integrin were determined by the real-time method of RT-PCR.

RESULTS

Developed Regorafenib resistant LS-180 showed to have Regorafenib IC50 of 38.96 ± 1.72 µM whereas IC50 in non-resistant cells were 8.51 ± 0.29 µM, which meaningful was lower statistically compared to that of a resistant one. The β1 mRNA level of whole α5β1 integrin was significantly higher in the resistant cells compared to those of non-resistant ones. Gene expression levels in each siRNA-loaded nanoparticle and Quercetin-loaded one were lower than that in mock experiments. Finally, when these two types of nanoparticles were used to treat resistant cells, gene expression decrease of integrin indicated a greater effect that could be capable of reverse resistancy.

CONCLUSION

Results of this study demonstrated another confirmation of involving integrins in cancer resistance following chemotherapy using Regorafenib. Also, it indicated how using siRNA targeting integrin could enhance the plant derivatives like Quercetin effects to reverse resistance in vitro.

Telomerase inhibitor MST-312 and quercetin synergistically inhibit cancer cell proliferation by promoting DNA damage

Quercetin is a natural flavonoid with well-established anti-proliferative activities against a variety of cancers. Telomerase inhibitor MST-312 also exhibits anti-proliferative effect on various cancer cells independent of its effect on telomere shortening. However, due to their low absorption and toxicity at higher doses, their clinical development is limited. In the present study, we examine the synergistic potential of their combination in cancer cells, which may result in a decrease in the therapeutic dosage of these compounds. We report that MST-312 and quercetin exhibit strong synergism in ovarian cancer cells with combination index range from 0.2 to 0.7. Co-treatment with MST-312 and quercetin upregulates the DNA damage and augments apoptosis when compared to treatment with either compound alone or a vehicle. We also examined the effect of these compounds on the proliferation of normal ovarian surface epithelial cells (OSEs). MST-312 has a cytoprotective impact in OSEs at lower dosages, but is inhibitory at higher doses. Quercetin did not affect the OSEs proliferation at low concentrations while at higher concentrations it is inhibitory. Notably, combination of MST-312 and quercetin had no discernible impact on OSEs. These observations have significant implications for future efforts towards maximizing efficacy in cancer therapeutics as this co-treatment specifically affects cancer cells and reduces the effective dosage of both the compounds.

Advances in Dietary Phenolic Compounds to Improve Chemosensitivity of Anticancer Drugs

Simple Summary

Several dietary phenolic compounds isolated from medicinal plants exert significant anticancer effects via several mechanisms. They induce apoptosis, autophagy, telomerase inhibition, and angiogenesis. Certain dietary phenolic compounds increase the effectiveness of drugs used in conventional chemotherapy. Some clinical uses of dietary phenolic compounds for treating certain cancers have shown remarkable therapeutic results, suggesting effective incorporation in anticancer treatments in combination with traditional chemotherapeutic agents.

Abstract

Despite the significant advances and mechanistic understanding of tumor processes, therapeutic agents against different types of cancer still have a high rate of recurrence associated with the development of resistance by tumor cells. This chemoresistance involves several mechanisms, including the programming of glucose metabolism, mitochondrial damage, and lysosome dysfunction. However, combining several anticancer agents can decrease resistance and increase therapeutic efficacy. Furthermore, this treatment can improve the effectiveness of chemotherapy. This work focuses on the recent advances in using natural bioactive molecules derived from phenolic compounds isolated from medicinal plants to sensitize cancer cells towards chemotherapeutic agents and their application in combination with conventional anticancer drugs. Dietary phenolic compounds such as resveratrol, gallic acid, caffeic acid, rosmarinic acid, sinapic acid, and curcumin exhibit remarkable anticancer activities through sub-cellular, cellular, and molecular mechanisms. These compounds have recently revealed their capacity to increase the sensitivity of different human cancers to the used chemotherapeutic drugs. Moreover, they can increase the effectiveness and improve the therapeutic index of some used chemotherapeutic agents. The involved mechanisms are complex and stochastic, and involve different signaling pathways in cancer checkpoints, including reactive oxygen species signaling pathways in mitochondria, autophagy-related pathways, proteasome oncogene degradation, and epigenetic perturbations.

Chemical Compounds of Berry-Derived Polyphenols and Their Effects on Gut Microbiota, Inflammation, and Cancer

Berry-derived polyphenols are bioactive compounds synthesized and secreted by several berry fruits. These polyphenols feature a diversity of chemical compounds, including phenolic acids and flavonoids. Here, we report the beneficial health effects of berry-derived polyphenols and their therapeutical application on gut-microbiota-related diseases, including inflammation and cancer. Pharmacokinetic investigations have confirmed the absorption, availability, and metabolism of berry-derived polyphenols. In vitro and in vivo tests, as well as clinical trials, showed that berry-derived polyphenols can positively modulate the gut microbiota, inhibiting inflammation and cancer development. Indeed, these compounds inhibit the growth of pathogenic bacteria and also promote beneficial bacteria. Moreover, berry-derived polyphenols exhibit therapeutic effects against different gut-microbiota-related disorders such as inflammation, cancer, and metabolic disorders. Moreover, these polyphenols can manage the inflammation via various mechanisms, in particular the inhibition of the transcriptional factor Nf-κB. Berry-derived polyphenols have also shown remarkable effects on different types of cancer, including colorectal, breast, esophageal, and prostate cancer. Moreover, certain metabolic disorders such as diabetes and atherosclerosis were also managed by berry-derived polyphenols through different mechanisms. These data showed that polyphenols from berries are a promising source of bioactive compounds capable of modulating the intestinal microbiota, and therefore managing cancer and associated metabolic diseases. However, further investigations should be carried out to determine the mechanisms of action of berry-derived polyphenol bioactive compounds to validate their safety and examinate their clinical uses.

Application of Quercetin in the Treatment of Gastrointestinal Cancers

Many cellular signaling pathways contribute to the regulation of cell proliferation, division, motility, and apoptosis. Deregulation of these pathways contributes to tumor cell initiation and tumor progression. Lately, significant attention has been focused on the use of natural products as a promising strategy in cancer treatment. Quercetin is a natural flavonol compound widely present in commonly consumed foods. Quercetin has shown significant inhibitory effects on tumor progression via various mechanisms of action. These include stimulating cell cycle arrest or/and apoptosis as well as its antioxidant properties. Herein, we summarize the therapeutic effects of quercetin in gastrointestinal cancers (pancreatic, gastric, colorectal, esophageal, hepatocellular, and oral).

Quercetin synergistically potentiates the anti-metastatic effect of 5-fluorouracil on the MDA-MB-231 breast cancer cell line

OBJECTIVES

Breast cancer (BC) cells' ability to metastasize to other tissues increases mortality. The Matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9) facilitate cancer cell migration. 5-fluorouracil is a frequently applied chemotherapeutic agent in cancer treatment with destructive side effects on normal tissues. Hence, researchers have focused on finding a way to reduce the dose of chemotherapeutic drugs. Quercetin, a natural polyphenolic compound, has inhibitory effects on proliferation and migration of tumor cells. This study evaluated the effect of the combination of Quercetin and 5-fluorouracil on migration of the MDA-MB-231 breast cancer cell line.

MATERIALS AND METHODS

The effect of Quercetin, 5-fluorouracil , and their combination on MDA-MB-231 breast cancer cell proliferation was investigated through MTT assay. Inhibition of tumor cell migration was examined by wound healing assay. Finally, the effect of treatments on gene expression of MMP-2 and MMP-9 was evaluated by quantitative real-time PCR.

RESULTS

The IC50 values for Quercetin and 5-fluorouracil after 48 hr treatment were 295 μM and 525 μM, respectively. The combination index (CI) for Quercetin and 5-fluorouracil was <1, indicating synergy between them. The combination of Quercetin plus 5-fluorouracil resulted in a significant reduction in migration rate and MMP-2 and MMP-9 gene expressions of MDA-MB-231 cancer cells compared with the individual application of 5-FU.

CONCLUSION

Quercetin enhances the suppressory effect of 5-fluorouracil on migration of BC cells. The combination of Quercetin and 5-fluorouracil can be an attractive field for future studies.

Research Progress in Flavonoids as Potential Anticancer Drug Including Synergy with Other Approaches

BACKGROUND

In chemotherapy for cancer, conventional drugs aim to target the rapidly growing and dividing cells at the early stages. However, at an advanced stage, cancer cells become less susceptible because of the multidrug resistance and the recruitment of alternative salvage pathways for their survival. Besides, owing to target non-selectivity, healthy proliferating cells also become vulnerable to the damage. The combination therapies offered using flavonoids to cure cancer not only exert an additive effect against cancer cells by targetting supplementary cell carnage pathways but also hampers the drug resistance mechanisms. Thus, the review aims to discuss the potential and pharmacokinetic limitations of flavonoids in cancer treatment. Further successful synergistic studies reported using flavonoids to treat cancer has been described along with potential drug delivery systems.

METHODS

A literature search was done by exploring various online databases like Pubmed, Scopus, and Google Scholar with the specific keywords like "Anticancer drugs", "flavonoids", "oncology research", and "pharmacokinetics".

RESULTS

Dietary phytochemicals, mainly flavonoids, hinder cell signalling responsible for multidrug resistance and cancer progression, primarily targeting cancer cells sparing normal cells. Such properties establish flavonoids as a potential candidate for synergistic therapy. However, due to low absorption and high metabolism rates, the bioavailability of flavonoids becomes a challenge. Such challenges may be overcome using novel approaches like derivatization, and single or co-delivery nano-complexes of flavonoids with conventional drugs. These new approaches may improve the pharmacokinetic and pharmacodynamic of flavonoids.

CONCLUSION

This review highlights the application of flavonoids as a potential anticancer phytochemical class in combination with known anti-cancer drugs/nanoparticles. It also discusses flavonoid's pharmacokinetics and pharmacodynamics issues and ways to overcome such issues. Moreover, it covers successful methodologies employed to establish flavonoids as a safe and effective phytochemical class for cancer treatment.

Quercetin inhibits invasion and angiogenesis of esophageal cancer cells

BACKGROUND

Esophageal carcinoma has poor prognosis and novel therapies for esophageal carcinoma are urgently needed. Quercetin is a natural flavonoid compound that can be found in many foods. In this study, we investigated the effects of quercetin on invasion and angiogenesis of esophageal cancer cells.

METHODS

Human esophageal cancer cell line Eca109 was treated with 5 μg/mL or 10 μg/mL of quercetin. Colony formation assay was performed. Cell migration and invasion were evaluated by wound healing and transwell assays, respectively. Human umbilical vein/vascular endothelium cells (CLR-1730) were treated with Eca109 conditioned medium, and the effects of quercetin on CLR-1730 were evaluated by wound healing and tube formation assays. Protein levels of VEGF-A, MMP9, and MMP2 were determined by Western blotting.

RESULTS

The ability of colony forming in Eca109 was reduced with the administration of 10 μg/mL quercetin, but there was no difference between the 5 μg/mL quercetin group and control. The migration distance and the number of invasive cells were significantly reduced in the 10 μg/mL quercetin group. At the lower level of quercetin at 5 μg/mL, only the invasion of cells was significantly inhibited. In endothelial cells treated with Eca109 conditioned medium, cell migration and tube forming ability were suppressed. The decreased protein levels of VEGF-A, MMP9, and MMP2 were observed at the 10 μg/mL quercetin group.

CONCLUSION

Quercetin suppressed the invasion and angiogenesis of esophageal cancer cells, and the effects were associated with the decreased expression of VEGF-A, MMP2, and MMP9.

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.

Co-Delivery Anticancer Drug Nanoparticles for Synergistic Therapy Against Lung Cancer Cells

Introduction

This study aims to develop a novel co-delivery gefitinib and quercetin system loaded with PLGA-PEG nanoparticles and evaluate their antitumor activity in vitro and in vivo.

Methods

Gef/Qur NPs were prepared and characterized. The release of drugs, stability, cellular uptake and cytotoxicity were evaluated in vitro. The antitumor effects and systemic toxicity of different formulations were also investigated.

Results

Gef/Qur NPs displayed a smaller particle size and a PDI and zeta potential of 0.11 and −23.5 mV, respectively. The hydrophobic Gef and Qur content in NPs reached up to 65.2% and 56.4%, respectively, and their high entrapment efficiencies recorded 83.7% and 82.3%, respectively. The in vitro release of Gef/Qur from the NPs was sustained for 12 h. Compared with control groups, Gef/Qur NPs showed higher cellular uptake and cell inhibition rates. In vivo studies identified the lungs as the target tissue and the region of maximum drug release. Through pharmacodynamics analysis, we found that two drugs (Gef and Qur) were incorporated into one nanoparticle carrier, which played a good role in generating synergistic effect.

Discussion

It is concluded that PLGA-PEG is an ideal drug carrier for the co-delivery of Gef/Qur to treat lung cancer.

Quercetin as an anticancer agent: Focus on esophageal cancer

Esophageal cancer (EC) is regarded as the sixth highest contributor to all cancer-related mortality, worldwide. In spite of advances in the treatment of EC, currently used methods remain ineffective. Quercetin, as a dietary antioxidant, is a plant flavonol from the flavonoid group of polyphenols, and can be found in numerous vegetables, fruits, and herbs. Quercetin can affect the processes of cancer-related diseases via cell proliferation inhibitory effects, potential apoptosis effects, and antioxidant properties. Of the various types of cancer, the use of quercetin has now become prominent in the treatment of EC. In this review, we discuss how quercetin may be an important supplement for the prevention, treatment, and management of EC, owing to its natural origin, and low-cost relative to synthetic cancer drugs. However, most findings cited in the current study are based on in vitro and in vivo studies, and thus, further human-based research is necessitated. PRACTICAL APPLICATIONS: In spite of advances in the treatment of esophageal cancer, currently used methods remain ineffective, therefore, an alternative or complementary therapy is required. Quercetin, as a dietary antioxidant, can affect the processes of cancer-related diseases via cell proliferation inhibitory effects, potential proapoptotic functions, and antioxidant properties. Quercetin may be an important supplement for the prevention, treatment, and management of EC, owing to its natural origin. The low cost of quercetin as supplement or dietary intake, relative to synthetic cancer drugs, is an advantage of the compound which should be considered.

LncRNA HOTAIR-mediated MTHFR methylation inhibits 5-fluorouracil sensitivity in esophageal cancer cells

BACKGROUND

Esophageal cancer (EC) represents one of the most aggressive digestive neoplasms globally, with marked geographical variations in morbidity and mortality. Chemoprevention is a promising approach for cancer therapy, while acquired chemoresistance is a major obstacle impeding the success of 5-fluorouracil (5-FU)-based chemotherapy in EC, with the mechanisms underlying resistance not well-understood. In the present study, we focus on exploring the role of long non-coding RNA (lncRNA) HOTAIR in EC progression and sensitivity of EC cells to 5-FU.

METHODS

Paired cancerous and pre-cancerous tissues surgically resected from EC patients were collected in this study. Promoter methylation of the MTHFR was assessed by methylation-specific PCR. RIP and ChIP assays were adopted to examine the interaction of DNA methyltransferases (DNMTs) with lncRNA HOTAIR and MTHFR, respectively. EC cells resistant to 5-FU were induced by step-wise continuous increasing concentrations of 5-FU. The sensitivity of EC cells to 5-FU in vivo was evaluated in nude mice treated with xenografts of EC cells followed by injection with 5-FU (i.p.).

RESULTS

We found reciprocal expression patterns of lncRNA HOTAIR and MTHFR in EC tissues and human EC cells. Interference with lncRNA HOTAIR enhanced 5-FU-induced apoptosis, exhibited anti-proliferative activity, and reduced promoter methylation of the MTHFR in EC cells. Besides, overexpression of MTHFR attenuated the acquired chemoresistance induced by overexpression of lncRNA HOTAIR in EC cells. At last, enhanced chemosensitivity was observed in vivo once nude mice xenografted with lncRNA HOTAIR-depleted EC cells.

CONCLUSION

Together, our study proposes that pharmacologic targeting of lncRNA HOTAIR sensitizes EC cells to 5-FU-based chemotherapy by attenuating the promoter hypermethylation of the MTHFR in EC.

Lycopene, sulforaphane, quercetin, and curcumin applied together show improved antiproliferative potential in colon cancer cells in vitro

Lycopene, sulforaphane, quercetin, and curcumin, ingredients of daily diet, show significant anticancer and chemopreventive potential; however, no data are available showing thorough evaluation of jointly used phytochemicals on cancer cell proliferation. Here, we compare anticancer potential of mentioned substances applied separately or in combination (as MIX) by measuring mitochondrial activity (MTT test), DNA synthesis (BrdU test) and lactate dehydrogenase release (LDH test) in colon epithelial (CCD841 CoTr), and colon cancer (HT-29, LS174T) cells. Additive inhibitory effect of simultaneously used phytochemicals on cancer cells proliferation has been shown. In epithelial cells, tested combination effectively inhibited mitochondrial activity, but not DNA synthesis. LDH test revealed cytotoxicity of tested mixture against cancer cells without negative effect on normal cells. Furthermore, we demonstrated that MIX enhances antiproliferative effect of common cytostatics: 5-fluorouracil and cisplatin. Presented data suggest chemopreventive potential of the proposed combination of natural substances and their usefulness as adjuvant strategy during chemotherapy. PRACTICAL APPLICATIONS: Colorectal cancer is one of the most common causes of cancer death worldwide. Since its development and progression is strongly correlated with dietary habits, healthy diet as well as supplementation with proved anticancer agents seems to be reasonable strategy of colon cancer prevention and treatment. In the present study, we have focused on four natural compounds abundantly found in daily diet i.e., lycopene, sulforaphane, quercetin, and curcumin, with well established anticancer potential. Their individual and collective impact both on normal colon epithelium cells and colon cancer cells viability, growth, and proliferation was examined. Furthermore, activity of the substances combined as MIX to influence antiproliferative potential of commonly used in colon cancer treatment cytostatics, 5-fluorouracil, and cisplatin was verified. Proposed in the study combination of phytochemicals with experimentally proven antiproliferative activity may propose an effective strategy for prevention and treatment of colon cancer.

Long noncoding RNA LINC00261 induces chemosensitization to 5-fluorouracil by mediating methylation-dependent repression of DPYD in human esophageal cancer

Approximately 85% of a single administered dose of 5-fluorouracil (5-FU) will be degraded by dihydropyrimidine dehydrogenase (DYPD). Studies have highlighted a link between the complete or partial loss of DYPD function and clinical responses to 5-FU; however, the underlying molecular basis of DPD deficiency remains poorly understood. Hence, the aim of the present study was to evaluate the prevailing hypothesis which suggests that overexpression of LINC00261 possesses the ability to modulate the methylation-dependent repression of DPYD, ultimately resulting in an elevation of the sensitivity of human esophageal cancer cells to 5-FU. LINC00261 levels were initially quantified, followed by analysis of DYPD methylation within the cancerous tissues collected from 75 patients diagnosed with esophageal cancer undergoing 5-FU-based adjuvant chemotherapy. In an attempt to determine the levels of LINC00261 related to the esophageal cancer cell resistance to 5-FU and to identify the interaction between the levels of LINC00261 and methylation of the DYPD promoter, esophageal cancer cells TE-1 and -5 were prepared, in which LINC00261 and the 5-FU-resistant TE-1 and -5 cells were overexpressed. The levels of LINC00261 were reduced among the cancerous tissues obtained from patients exhibiting resistance to 5-FU. Overexpression of LINC00261 was determined to dramatically inhibit proliferation and resistance to apoptosis among 5-FU-resistant TE-1 and -5 cells, whereas silencing of LINC00261 was determined to enhance proliferation and resistance to apoptosis among the TE-1 and -5 cells. DPYD, a confirmed target of LINC00261, displayed a greater incidence of DNA methylation among patient's sensitive to 5-FU. A key finding revealed that overexpressed LINC00261 could increase the methylation of the DPYD promoter through the recruitment of DNA methyltransferase (DNMT), which, in turn, acts to decrease DPYD activity in 5-FU-resistant TE-1 cells, whereas a reversible change was recorded once the demethylation reagent 5-aza-2'-deoxyctidine was employed to treat the 5-FU-resistant TE-1 cells. Taken together, the results of the study provided evidence emphasizing the distinct antitumor ability of LINC00261 in cases of esophageal cancer, which was manifested by overexpression of LINC00261 detected to increase the sensitivity of human esophageal cancer cells to 5-FU by mediating methylation-dependent repression of DPYD. Our study highlighted the potential of LINC00261 as a novel target capable of improving the chemotherapeutic response and survival of patients with esophageal cancer.-Lin, K., Jiang, H., Zhuang, S.-S., Qin, Y.-S., Qiu, G.-D., She, Y.-Q., Zheng, J.-T., Chen, C., Fang, L., Zhang, S.-Y. Long noncoding RNA LINC00261 induces chemosensitization to 5-fluorouracil by mediating methylation-dependent repression of DPYD in human esophageal cancer.

RGD-modified nanoliposomes containing quercetin for lung cancer targeted treatment

Purpose

The aim of this study was to prepare RGD-modified nanoliposomes containing quercetin (QCT) distearoyl-L-a-phosphatidylethanolamine-polyethylene glycol 2000-RGD-liposomes ([DSPE]-PEG2000-RGD-LPs/QCT) for lung cancer targeting treatment.

Methods

The physicochemical parameters of (DSPE)-PEG2000-RGD-LPs/QCT were characterized in terms of the particle size, zeta potential, morphology, entrapment efficiency, drug loading, and in vitro release behavior. In vivo, pharmacokinetics and antitumor studies of prepared formulations were also evaluated.

Results

In this study, QCT was found to be easily dispersed in lipid solution and entrapped by the thin-film hydration method. The encapsulation ratio and drug loading of prepared LPs were 89.2%±7.4% and 9.2%±1.3% and the mean diameter was 93.4±7.2 nm from 3 batches. The results of in vitro experiments showed that the particle size of liposomes was suitable for the fenestrated vasculatures of cancer tissues via the enhanced permeability retention effect. In vitro, a relatively slow QCT release profile was observed in (DSPE)-PEG2000-RGD-LPs, and the release mechanism fit with the Higuchi equation better. In vivo imaging results indicated that RGD-modified LPs had very good tumor targeting ability. (DSPE)-PEG2000-RGD-LPs/QCT showed a significant antitumor activity in mice with A549 tumors.

Conclusion

Through this study, it was found that the RGD-modified LPs loaded with QCT could potentially be a very promising lung-targeted preparation.

The potential of herb medicines in the treatment of esophageal cancer

Esophageal cancer (EC) is one of common malignant neoplasms in the world. Due to dietary habits, environmental factors, stress and so on, larger numbers of person are diagnose with EC every year. Currently, the clinical treatment of EC mainly includes radiotherapy, chemotherapy, surgical resection alone or combined strategy. These treatment options are insufficient and often associated with a number of side effects. Medicinal herbs containing Traditional Chinese Medicine (TCM) have been used as an adjunct treatment for alleviating the side effects of chemotherapy or radiotherapy and for improving the quality of life of cancer patients. The monomer compounds obtained from medicinal herbs also exhibit potential anti-cancer activity against various type cancer cell lines including esophageal cancer, and have the ability to enhance cancer cells sensitizing to chemotherapy or radiotherapy. In this review, we summarize some monomers and composite of medicinal herbs with anti-cancer activity for EC, and elaborate their mechanism of action. Understanding the exact mechanism of their actions may provide valuable information for their possible application in cancer therapy and prevention. This is beneficial for the use and development of medicinal herbs for diseases therapy in the future.

Improving In Vivo Efficacy of Bioactive Molecules: An Overview of Potentially Antitumor Phytochemicals and Currently Available Lipid-Based Delivery Systems

Cancer is among the leading causes of morbidity and mortality worldwide. Many of the chemotherapeutic agents used in cancer treatment exhibit cell toxicity and display teratogenic effect on nontumor cells. Therefore, the search for alternative compounds which are effective against tumor cells but reduce toxicity against nontumor ones is of great importance in the progress or development of cancer treatments. In this sense, scientific knowledge about relevant aspects of nutrition intimately involved in the development and progression of cancer progresses rapidly. Phytochemicals, considered as bioactive ingredients present in plant products, have shown promising effects as potential therapeutic/preventive agents on cancer in several in vitro and in vivo assays. However, despite their bioactive properties, phytochemicals are still not commonly used in clinical practice due to several reasons, mainly attributed to their poor bioavailability. In this sense, new formulation strategies are proposed as carriers to improve their bioefficacy, highlighting the use of lipid-based delivery systems. Here, we review the potential antitumoral activity of the bioactive compounds derived from plants and the current studies carried out in animal and human models. Furthermore, their association with lipids as a formulation strategy to enhance their efficacy in vivo is also reported. The development of high effective bioactive supplements for cancer treatment based on the improvement of their bioavailability goes through this association.

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.

Synergistic Anticancer Activities of Natural Substances in Human Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is highly resistant to currently available chemotherapeutic agents. The clinical outcome of HCC treatment remains unsatisfactory. Therefore, new effective and well-tolerated therapy strategies are needed. Natural products are excellent sources for the development of new medications for disease treatment. Recently, we and other researchers have suggested that the combined effect of natural products may improve the effect of chemotherapy treatments against the proliferation of cancer cells. In addition, many combination treatments with natural products augmented intracellular reactive oxygen species (ROS). In this review we will demonstrate the synergistic anticancer effects of a combination of natural products with chemotherapeutic agents or natural products against human HCC and provide new insight into the development of novel combination therapies against HCC.

A Randomized Placebo-controlled Double Blind Clinical Trial of Quercetin for Treatment of Oral Lichen Planus

Background and aims. Standard treatment of oral lichen planus (OLP) includes topical or systemic corticosteroids that have many adverse effects. A trend toward alternative natural or herbal drugs has attended recently. This study was conducted to evaluate the effect of quercetin in treatment of erosive-atrophic OLP.

Materials and methods. Thirty patients participated in this randomized clinical trial from April 2010 to June 2010 (Trial Registration Number: NCT01375101). Patients were randomly allocated in two groups. Both groups received the standard treatment (dexamethasone mouthwash and nystatin suspension). Experimental group received oral 250 mg quercetin hydrate capsules (bid) and the control group received placebo capsules. The pain and severity of the lesions were recorded at the initial visit and the follow-ups. All recorded data were analyzed with chi-square, Mann-Whitney, t-test, Wilcoxon and Friedman tests using SPSS 11.5.

Results. There were no significant differences between the two groups in severity of the lesions and pain in the follow-ups.According to the Friedman test, there was a significant reduction in pain (P = 0.01) and severity indices (P = 0.00) in the case group. These differences were not observed in the control group(P = 0.26,SI; and P = 0.86, PI). No adverse effect of quercetin was reported.

Conclusion. According to the results, no significant therapeutic effect can be considered for quercetin in treatment of OLP.

Synergistic growth-suppressive effects of quercetin and cisplatin on HepG2 human hepatocellular carcinoma cells

Quercetin, a natural flavonoid, exhibits anticancer effects. The aim of this study is to determine whether the combination of quercetin with cisplatin, a conventional chemotherapeutic drug, would have synergistic suppressive effects on hepatocellular carcinoma (HCC) cells. To this end, HepG2 cells were exposed to quercetin (50 μM) or cisplatin (10 μM) alone or combination of both and cell proliferation and apoptosis were investigated. Our data revealed that the combination of quercetin and cisplatin was significantly (P < 0.05) effective in inducing growth suppression and apoptosis in HepG2 cells, when compared with single agent treatment. Quercetin combined with cisplatin modulated the expression of numerous genes involved in cell cycle progression and apoptosis. Treatment with quercetin rather than cisplatin resulted in a marked elevation of p16 expression in HepG2 cells. Targeted reduction of p16 using RNA interference technology partially reversed quercetin-induced cell cycle G1 arrest and apoptosis in HepG2 cells. In conclusion, quercetin has suppressive activity against HCC cells through p16-mediated cell cycle arrest and apoptosis and its combination with cisplatin yielded synergistic inhibitory effects in suppressing cell growth and inducing apoptosis.

Involvement of chromosome region maintenance 1 (CRM1) in the formation and progression of esophageal squamous cell carcinoma

Chromosome region maintenance 1 (CRM1) has been related to several malignancies. The predictive value of CRM1 in the malignance and prognosis of esophageal squamous cell carcinoma (ESCC), however, is not clear yet. In this study, we displayed that CRM1 expression was up-regulated in ESCC using immunohistochemistry and Western blot. Statistical analysis demonstrated that patients with high CRM1 levels indicated shorter survival period. We further found that silencing CRM1 caused apoptosis in ESCC cell lines. Moreover, knockdown of CRM1 disturbed the expression of tumor suppressor proteins and inhibited NF-κB activity in ESCC cell lines, especially if the cell line was treated with 5-fluorouracil. In consequence, our results for the first time indicated that CRM1 was dysregulated in ESCC, and suppression of CRM1 expression which resulted in inhibiting of NF-κB signaling might be developed into a new strategy in ESCC therapy.

Site-specific anticancer effects of dietary flavonoid quercetin

Food-derived flavonoid quercetin, widely distributed in onions, apples, and tea, is able to inhibit growth of various cancer cells indicating that this compound can be considered as a good candidate for anticancer therapy. Although the exact mechanism of this action is not thoroughly understood, behaving as antioxidant and/or prooxidant as well as modulating different intracellular signalling cascades may all play a certain role. Such inhibitory activity of quercetin has been shown to depend first of all on cell lines and cancer types; however, no comprehensive site-specific analysis of this effect has been published. In this review article, cytotoxicity constants of quercetin measured in various human malignant cell lines of different origin were compiled from literature and a clear cancer selective action was demonstrated. The most sensitive malignant sites for quercetin revealed to be cancers of blood, brain, lung, uterine, and salivary gland as well as melanoma whereas cytotoxic activity was higher in more aggressive cells compared to the slowly growing cells showing that the most harmful cells for the organism are probably targeted. More research is needed to overcome the issues of poor water solubility and relatively low bioavailability of quercetin as the major obstacles limiting its clinical use.

Proteomic analysis of differentially expressed proteins in 5-fluorouracil-treated human breast cancer MCF-7 cells

BACKGROUND

5-Fluorouracil (5-Fu) is a commonly used chemotherapeutic agent in clinical care of breast cancer patients. However, the mechanism of how the 5-Fu works is complex and still largely unknown.

OBJECTIVE

The objective of this study was to understand the mechanism further and explore the new targets of 5-Fu.

METHODS

The differentially expressed proteins induced by 5-Fu in human breast cancer MCF-7 cells were identified by proteomic analysis. Four differentially expressed proteins were validated using Western blot and quantitative real-time reverse-transcription polymerase chain reaction analysis for protein and mRNA levels. The effect of 5-Fu on MCF-7 cells was determined by cell viability assay, transmission electron microscopy and flow cytometry analysis.

RESULTS

5-Fu dose-dependently inhibited cell proliferation with the IC50 value of 98.2 μM. 5-Fu also induced obviously morphological change and apoptosis in MCF-7 cells. Twelve differentially expressed proteins involved in energy metabolism, cytoskeleton, cellular signal transduction and tumor invasion and metastasis were identified.

CONCLUSION

These results may provide a new insight into the molecular mechanism of 5-Fu in therapy of breast cancer.

Venus Flytrap (Dionaea muscipula Solander ex Ellis) Contains Powerful Compounds that Prevent and Cure Cancer

Chemoprevention uses natural or synthetic molecules without toxic effects to prevent and/or block emergence and development of diseases including cancer. Many of these natural molecules modulate mitogenic signals involved in cell survival, apoptosis, cell cycle regulation, angiogenesis, or on processes involved in the development of metastases occur naturally, especially in fruits and vegetables bur also in non-comestible plants. Carnivorous plants including the Venus flytrap (Dionaea muscipula Solander ex Ellis) are much less investigated, but appear to contain a wealth of potent bioactive secondary metabolites. Aim of this review is to give insight into molecular mechanisms triggered by compounds isolated from these interesting plants with either therapeutic or chemopreventive potential.