Apigenin potentiates the growth inhibitory effects by IKK-β-mediated NF-κB activation in pancreatic cancer cells

Cancer chemoprevention: signaling pathways and strategic approaches

Although cancer chemopreventive agents have been confirmed to effectively protect high-risk populations from cancer invasion or recurrence, only over ten drugs have been approved by the U.S. Food and Drug Administration. Therefore, screening potent cancer chemopreventive agents is crucial to reduce the constantly increasing incidence and mortality rate of cancer. Considering the lengthy prevention process, an ideal chemopreventive agent should be nontoxic, inexpensive, and oral. Natural compounds have become a natural treasure reservoir for cancer chemoprevention because of their superior ease of availability, cost-effectiveness, and safety. The benefits of natural compounds as chemopreventive agents in cancer prevention have been confirmed in various studies. In light of this, the present review is intended to fully delineate the entire scope of cancer chemoprevention, and primarily focuses on various aspects of cancer chemoprevention based on natural compounds, specifically focusing on the mechanism of action of natural compounds in cancer prevention, and discussing in detail how they exert cancer prevention effects by affecting classical signaling pathways, immune checkpoints, and gut microbiome. We also introduce novel cancer chemoprevention strategies and summarize the role of natural compounds in improving chemotherapy regimens. Furthermore, we describe strategies for discovering anticancer compounds with low abundance and high activity, revealing the broad prospects of natural compounds in drug discovery for cancer chemoprevention. Moreover, we associate cancer chemoprevention with precision medicine, and discuss the challenges encountered in cancer chemoprevention. Finally, we emphasize the transformative potential of natural compounds in advancing the field of cancer chemoprevention and their ability to introduce more effective and less toxic preventive options for oncology.

Botanical Flavonoids: Efficacy, Absorption, Metabolism and Advanced Pharmaceutical Technology for Improving Bioavailability

Flavonoids represent a class of natural plant secondary metabolites with multiple activities including antioxidant, antitumor, anti-inflammatory, and antimicrobial properties. However, due to their structural characteristics, they often exhibit low bioavailability in vivo. In this review, we focus on the in vivo study of flavonoids, particularly the effects of gut microbiome on flavonoids, including common modifications such as methylation, acetylation, and dehydroxylation, etc. These modifications aim to change the structural characteristics of the original substances to enhance absorption and bioavailability. In order to improve the bioavailability of flavonoids, we discuss two feasible methods, namely dosage form modification and chemical modification, and hope that these approaches will offer new insights into the application of flavonoids for human health. In this article, we also introduce the types, plant sources, and efficacy of flavonoids. In conclusion, this is a comprehensive review on how to improve the bioavailability of flavonoids.

The synthesis and bioactivity of apigenin derivatives

BACKGROUND

Apigenin, a naturally occurring compound with a flavone core structure, is known for its diverse bioactivities, including anti-inflammation, anti-toxicant, anti-cancer and so on. There has been significant interest in the medicinal chemistry community. To address these challenges, researchers have developed various derivatives of apigenin to address challenges such as poor water-solubility and low intestinal absorption, aiming to enhance the pharmacological activities and pharmacokinetic properties of this compound.

OBJECTIVE

In recent years, there has been a proliferation of apigenin derivatives with enhanced bioactivity. However, there is a lack of comprehensive reviews on the function-based modification of these derivatives. In this paper, we provide an overview of the apigenin derivatives with varying bioactivities and explored their structure activity relationships. And the functions of different groups of apigenin derivatives were also analyzed.

CONCLUSION

This review summarized the current achievements that could provide some clues for further study of apigenin-based drugs.

Therapeutic potential of flavonoids from traditional Chinese medicine in pancreatic cancer treatment

Pancreatic cancer (PC) is a highly aggressive malignancy with rising mortality rates globally. Its diagnosis is often challenging due to its asymptomatic nature in the early stages. Consequently, most patients receive a poor prognosis, with low survival rates within 5 years, as the disease is typically detected at an advanced stage, complicating effective treatment. Flavonoids, especially those derived from traditional Chinese herbal medicines, have attracted considerable attention for their potent anti-PC properties. This review highlights the therapeutic potential of these bioactive compounds, which modulate key biological pathways, making them promising candidates for PC intervention. Their mechanisms of action include the regulation of autophagy, apoptosis, cell growth, epithelial-mesenchymal transition, and oxidative stress, as well as enhancing chemotherapeutic sensitivity, exerting antiangiogenic effects, and potentially boosting immunomodulatory responses. The demonstrated benefits of these natural compounds in cancer management have spurred extensive academic interest. Beyond their role as anti-cancer agents, flavonoids may provide both preventive and therapeutic advantages for PC, resonating with the core principles of traditional Chinese medicine for disease prevention and holistic treatment.

Plant‐Derived Phytochemicals and Their Nanoformulations for Inducing Programed Cell Death in Cancer

Phytochemicals are a diverse class of compounds found in various plant‐based foods and beverages that have displayed the capacity to exert powerful anticancer effects through the induction of programed cell death (PCD) in malignancies. PCD is a sophisticated process that maintains in upholding tissue homeostasis and eliminating injured or neoplastic cells. Phytochemicals have shown the potential to induce PCD in malignant cells through various mechanisms, including modulation of cell signaling pathways, regulation of reactive oxygen species (ROS), and interaction with critical targets in cells such as DNA. Moreover, recent studies have suggested that nanomaterials loaded with phytochemicals may enhance cell death in tumors, which can also stimulate antitumor immunity. In this review, a comprehensive overview of the current understanding of the anticancer effects of phytochemicals and their potential as a promising approach to cancer therapy, is provided. The impacts of phytochemicals such as resveratrol, curcumin, apigenin, quercetin, and some approved plant‐derived drugs, such as taxanes on the regulation of some types of PCD, including apoptosis, pyroptosis, anoikis, autophagic cell death, ferroptosis, and necroptosis, are discussed. The underlying mechanisms and the potential of nanomaterials loaded with phytochemicals to enhance PCD in tumors are also explained.

Signaling controversy and future therapeutical perspectives of targeting sphingolipid network in cancer immune editing and resistance to tumor necrosis factor-α immunotherapy

Anticancer immune surveillance and immunotherapies trigger activation of cytotoxic cytokine signaling, including tumor necrosis factor-α (TNF-α) and TNF-related apoptosis-inducing ligand (TRAIL) pathways. The pro-inflammatory cytokine TNF-α may be secreted by stromal cells, tumor-associated macrophages, and by cancer cells, indicating a prominent role in the tumor microenvironment (TME). However, tumors manage to adapt, escape immune surveillance, and ultimately develop resistance to the cytotoxic effects of TNF-α. The mechanisms by which cancer cells evade host immunity is a central topic of current cancer research. Resistance to TNF-α is mediated by diverse molecular mechanisms, such as mutation or downregulation of TNF/TRAIL receptors, as well as activation of anti-apoptotic enzymes and transcription factors. TNF-α signaling is also mediated by sphingosine kinases (SphK1 and SphK2), which are responsible for synthesis of the growth-stimulating phospholipid, sphingosine-1-phosphate (S1P). Multiple studies have demonstrated the crucial role of S1P and its transmembrane receptors (S1PR) in both the regulation of inflammatory responses and progression of cancer. Considering that the SphK/S1P/S1PR axis mediates cancer resistance, this sphingolipid signaling pathway is of mechanistic significance when considering immunotherapy-resistant malignancies. However, the exact mechanism by which sphingolipids contribute to the evasion of immune surveillance and abrogation of TNF-α-induced apoptosis remains largely unclear. This study reviews mechanisms of TNF-α-resistance in cancer cells, with emphasis on the pro-survival and immunomodulatory effects of sphingolipids. Inhibition of SphK/S1P-linked pro-survival branch may facilitate reactivation of the pro-apoptotic TNF superfamily effects, although the role of SphK/S1P inhibitors in the regulation of the TME and lymphocyte trafficking should be thoroughly assessed in future studies.

In silico study of polyphenols as potential inhibitors of MALT1 protein in non-Hodgkin lymphoma

Non-Hodgkin lymphoma (NHL) is one of the most common cancer types. Deregulated signaling pathways can trigger certain NHL subtypes, including Diffuse Large B-cell lymphoma. NF-ĸB signaling pathway, which is responsible for the proliferation, growth, and survival of cells, has an essential role in lymphoma development. Although different signals control NF-ĸB activation in various lymphoid malignancies, the characteristic one is the CARD11-BCL10-MALT1 (CBM) complex. The CBM complex is responsible for the initiation of adaptive immune response. Our study is focused on the molecular docking of ten polyphenols as potential CARD11-BCL10-MALT1 complex inhibitors, essentially through MALT1 inhibition. Molecular docking was performed by Auto Dock Tools and AutoDock Vina tool, while SwissADME was used for drug-likeness and absorption, distribution, metabolism, excretion, and toxicity (ADMET) analysis of the ligands. Out of 66 ligands that were used in this study, we selected and visualized five. Selection criteria were based on the binding energy score and position of the ligands on the used protein. 2D and 3D visualizations showed interactions of ligands with the protein. Five ligands are considered potential inhibitors of MALT1, thus affecting NF-ĸB signaling pathway. However, additional in vivo and in vitro studies are required to confirm their mechanism of inhibition.

Apigenin inhibits macrophage pyroptosis through regulation of oxidative stress and the NF-κB pathway and ameliorates atherosclerosis

Pyroptosis plays an important role in inflammatory diseases such as viral hepatitis and atherosclerosis. Apigenin exhibits various bioactivities, particularly anti-inflammation, but its effect on pyroptosis remains unclear. The aim of this study is to investigate the effect of apigenin on pyroptosis and explore its potential against inflammatory diseases. THP-1 macrophages treated by lipopolysaccharides/adenosine 5'-triphosphate were used as the in vitro pyroptosis model. Western blot was used to detect the expression of NLRP3 inflammasome components and key regulators. Immunofluorescence was used to observe ROS production and intracellular location of p65. The potential of apigenin against inflammatory diseases was evaluated using atherosclerotic mice. Plaque progression was observed by pathological staining. Immunofluorescence was used to observe the expression of NLRP3 inflammasome components in plaques. The results showed that apigenin inhibited NLRP3 inflammasome activation. Apigenin reduced ROS overproduction and inhibited p65 nuclear translocation. Additionally, apigenin decreased the expression of NLRP3 inflammasome components in the plaque. Plaque progression was inhibited by apigenin. In conclusion, apigenin exhibited a preventive effect on macrophage pyroptosis by reducing oxidative stress and inhibiting the NF-κB pathway. Apigenin may alleviate atherosclerosis at least partially by inhibiting macrophage pyroptosis. These findings suggest apigenin to be a promising therapeutic agent for inflammatory diseases.

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.

The Potential Role of Apigenin in Cancer Prevention and Treatment

Cancer is the leading cause of death worldwide. In spite of advances in the treatment of cancer, currently used treatment modules including chemotherapy, hormone therapy, radiation therapy and targeted therapy causes adverse effects and kills the normal cells. Therefore, the goal of more effective and less side effects-based cancer treatment approaches is still at the primary position of present research. Medicinal plants or their bioactive ingredients act as dynamic sources of drugs due to their having less side effects and also shows the role in reduction of resistance against cancer therapy. Apigenin is an edible plant-derived flavonoid that has received significant scientific consideration for its health-promoting potential through modulation of inflammation, oxidative stress and various other biological activities. Moreover, the anti-cancer potential of apigenin is confirmed through its ability to modulate various cell signalling pathways, including tumor suppressor genes, angiogenesis, apoptosis, cell cycle, inflammation, apoptosis, PI3K/AKT, NF-κB, MAPK/ERK and STAT3 pathways. The current review mainly emphases the potential role of apigenin in different types of cancer through the modulation of various cell signaling pathways. Further studies based on clinical trials are needed to explore the role of apigenin in cancer management and explain the possible potential mechanisms of action in this vista.

Exploring the role of senescence inducers and senotherapeutics as targets for anticancer natural products

During the last few decades, cancer has remained one of the deadliest diseases that endanger human health, emphasizing urgent drug discovery. Cellular senescence has gained a great deal of attention in recent years because of its link to the development of cancer therapy. Senescent cells are incapable of proliferating due to irreversibly inhibited the initiation of the cell cycle pathways. However, senescent cells aggregate in tissues and produce a pro-inflammatory secretome called senescence-associated secretory phenotype (SASP) that can cause serious harmful effects if not managed properly. There is mounting evidence that senescent cells lead to various phases of tumorigenesis in various anatomical sites, owing mostly to the paracrine activities of the SASP. Therefore, a new treatment field called senotherapeutics has been established. Senotherapeutics are newly developed anticancer agents that have been demonstrated to inhibit cancer effectively. In light of recent findings, several promising natural products have been identified as senescence inducers and senotherapeutics, including, miliusanes, epigallocatechin gallate, phloretin, silybin, resveratrol, genistein, sulforaphane, quercetin, allicin, fisetin, piperlongumine, berberine, triptolide, tocotrienols and curcumin analogs. Several of them have already been validated through preclinical trials and exert an enormous potential for clinical trials. This review article focuses on and summarises the latest advances on cellular senescence and its potential as a target for cancer treatment and highlights the well-known natural products as senotherapeutics for cancer treatment.

Phyto-targeting the CEMIP Expression as a Strategy to Prevent Pancreatic Cancer Metastasis

INTRODUCTION

Metastasis of primary pancreatic cancer (PC) to adjacent or distant organs is responsible for the poor survival rate of affected individuals. Chemotherapy, radiotherapy, and immunotherapy are currently being prescribed to treat PC in addition to surgical resection. Surgical resection is the preferred treatment for PC that leads to 20% of 5-year survival, but only less than 20% of patients are eligible for surgical resection because of the poor prognosis. To improve the prognosis and clinical outcome, early diagnostic markers need to be identified, and targeting them would be of immense benefit to increase the efficiency of the treatment. Cell migration-inducing hyaluronan-binding protein (CEMIP) is identified as an important risk factor for the metastasis of various cancers, including PC. Emerging studies have pointed out the crucial role of CEMIP in the regulation of various signaling mechanisms, leading to enhanced migration and metastasis of PC.

METHODS

The published findings on PC metastasis, phytoconstituents, and CEMIP were retrieved from Pubmed, ScienceDirect, and Cochrane Library. Computational tools, such as gene expression profiling interactive analysis (GEPIA) and Kaplan-Meier (KM) plotter, were used to study the relationship between CEMIP expression and survival of PC individuals.

RESULTS

Gene expression analysis using the GEPIA database identified a stupendous increase in the CEMIP transcript in PC compared to adjacent normal tissues. KM plotter analysis revealed the impact of CEMIP on the overall survival (OS) and disease-free survival (DFS) among PC patients. Subsequently, several risk factors associated with PC development were screened, and their ability to regulate CEMIP gene expression was analyzed using computational tools.

CONCLUSION

The current review is focused on gathering information regarding the regulatory role of phytocomponents in PC migration and exploring their possible impact on the CEMIP expression.

Plectranthus ecklonii Benth: A Comprehensive Review Into its Phytochemistry and Exerted Biological Activities

Ethnopharmacological Relevance: Plectranthus genus (Lamiaceae family) contain several species with acknowledged ethnopharmacological uses, such as, for gastrointestinal and respiratory-related problems, due to their anti-inflammatory, antibacterial and antifungal properties. The bioactivity of isolated medicinal compounds from this genus justifies the increased interest in recent times for species of Plectranthus, placing them in the spotlight for natural product drug development. Aim of the study: To the best of our knowledge, this is the first review on the biological activities of Plectranthus ecklonii Benth. As such, the aim of this review was three-fold: 1) to summarize the chemical compounds isolated from P. ecklonii; 2) to collate the biological activities and mechanisms of action of these compounds from in vitro studies; and 3) to evaluate the documented uses and potential applications of this species, in order to postulate on the direction of pharmaceutical uses of this species. Materials and methods: An extensive database retrieval was performed using the electronic databases Web of Science, PubMed, Google Scholar and ScienceDirect. The search criteria consisted of the keywords "Plectranthus ecklonii", "Plectranthus ecklonii + review", "Plectranthus ecklonii + diterpenes" or "Plectranthus ecklonii + abietanes", "ecklonii + parviflorone D", searched individually and as combinations. Eligibility criteria were set out and titles in English, Portuguese and Spanish were reviewed, with all references included dating from 1970 to 2021. A total of 169 papers were selected and included. Chemical structures were drawn using ChemDraw 20.0, CID numbers were searched in PubChem and the PRISMA diagram was created using PowerPoint 2012. Results: To date, a total of 28 compounds have been isolated from P. ecklonii, including diterpenes, triterpenes, flavonoids, and hydroxycinnamic acids. Most focused on the antimicrobial action of its constituents, although compounds have demonstrated other bioactivities, namely antioxidant, anti-inflammatory and antitumor. The most recent studies emphasize the diterpenoids, particularly parviflorone D, with the help of nanotechnology. Conclusions: The widespread ethnobotanical and traditional uses of P. ecklonii can be scientifically justified by a range of biological activities, demonstrated by isolated secondary metabolites. These bioactivities showcase the potential of this species in the development of economically important active pharmaceutical ingredients, particularly in anticancer therapy.

Flavonoid-Based Cancer Therapy: An Updated Review

As cancers are one of the most important causes of human morbidity and mortality worldwide, researchers try to discover novel compounds and therapeutic approaches to decrease survival of cancer cells, angiogenesis, proliferation and metastasis. In the last decade, use of special phytochemical compounds and flavonoids was reported to be an interesting and hopeful tactic in the field of cancer therapy. Flavonoids are natural polyphenols found in plant, fruits, vegetables, teas and medicinal herbs. Based on reports, over 10,000 flavonoids have been detected and categorized into several subclasses, including flavonols, anthocyanins, flavanones, flavones, isoflavones and chalcones. It seems that the anticancer effect of flavonoids is mainly due to their antioxidant and anti inflammatory activities and their potential to modulate molecular targets and signaling pathways involved in cell survival, proliferation, differentiation, migration, angiogenesis and hormone activities. The main aim of this review is to evaluate the relationship between flavonoids consumption and cancer risk, and discuss the anti-cancer effects of these natural compounds in human cancer cells. Hence, we tried to collect and revise important recent in vivo and in vitro researches about the most effective flavonoids and their main mechanisms of action in various types of cancer cells.

Forecasting sensitive targets of the kynurenine pathway in pancreatic adenocarcinoma using mathematical modeling

In this study, a new mathematical model was established and validated to forecast and define sensitive targets in the kynurenine pathway (Kynp) in pancreatic adenocarcinoma (PDAC). Using the Panc-1 cell line, genetic profiles of Kynp molecules were tested. qPCR data were implemented in the algorithm programming (fmincon and lsqnonlin function) to estimate 35 parameters of Kynp variables by Matlab 2017b. All tested parameters were defined as non-negative and bounded. Then, based on experimental data, the function of the fmincon equation was employed to estimate the approximate range of each parameter. These calculations were confirmed by qPCR and Western blot. The correlation coefficient (R) between model simulation and experimental data (72 hours, in intervals of 6 hours) of every variable was >0.988. The analysis of reliability and predictive accuracy depending on qPCR and Western blot data showed high predictive accuracy of the model; R was >0.988. Using the model calculations, kynurenine (x3, a6), GPR35 (x4, a8), NF-kβp105 (x7, a16), and NF-kβp65 (x8, a18) were recognized as sensitive targets in the Kynp. These predicted targets were confirmed by testing gene and protein expression responses. Therefore, this study provides new interdisciplinary evidence for Kynp-sensitive targets in the treatment of PDAC.

The Anticancer Potential of Apigenin Via Immunoregulation

Apigenin is an edible flavonoid widely distributed in natural plants, including most vegetables and fruits. Previous studies have revealed that apigenin possesses multiple biological functions by demonstrating antiinflammatory, anti-oxidative, anti-bacterial, anti-viral, anti-tumor and cardiovascular protective effects. Furthermore, recent progressions have disclosed a novel perspective of the anti-cancer roles of apigenin through its immunoregulatory functions. With the rapid progression of the groundbreaking strategies being developed for cancer immunotherapy, its immunoregulatory roles are being recognized as intriguing features of the multifaceted apigenin. However, the current understanding of this emerging role of apigenin still remains limited. Therefore, in the present review, recent advances on the immunoregulatory properties of apigenin in various diseases with a special focus on neoplasm, are summarized. Clinical strategies of cancer immunotherapy are briefly introduced and findings on apigenin linked to immunoregulatory roles in immunotherapy-associated aspects are brought together. The bioactivity, bioavailability, toxicity and potential of apigenin, to be considered as a therapeutic agent in anti-tumor immunotherapy, is discussed. Disclosed molecular mechanisms underlying the immunoregulatory roles of apigenin in cancer immunotherapy are also summarized. Based on findings from the literature, apigenin has the potential to serve as a prospective adjuvant for anti-cancer immunotherapy and warrants further investigations.

Rationalizing the therapeutic potential of apigenin against cancer

BACKGROUND

Despite the remarkable advances made in the diagnosis and treatment of cancer during the past couple of decades, it remains the second largest cause of mortality in the world, killing approximately 9.6 million people annually. The major challenges in the treatment of the advanced stage of this disease are the development of chemoresistance, severe adverse effects of the drugs, and high treatment cost. Therefore, the development of drugs that are safe, efficacious, and cost-effective remains a 'Holy Grail' in cancer research. However, the research over the past four decades shed light on the cancer-preventive and therapeutic potential of natural products and their underlying mechanism of action. Apigenin is one such compound, which is known to be safe and has significant potential in the prevention and therapy of this disease.

AIM

To assess the literature available on the potential of apigenin and its analogs in modulating the key molecular targets leading to the prevention and treatment of different types of cancer.

METHOD

A comprehensive literature search has been carried out on PubMed for obtaining information related to the sources and analogs, chemistry and biosynthesis, physicochemical properties, biological activities, bioavailability and toxicity of apigenin.

KEY FINDINGS

The literature search resulted in many in vitro, in vivo and a few cohort studies that evidenced the effectiveness of apigenin and its analogs in modulating important molecular targets and signaling pathways such as PI3K/AKT/mTOR, JAK/STAT, NF-κB, MAPK/ERK, Wnt/β-catenin, etc., which play a crucial role in the development and progression of cancer. In addition, apigenin was also shown to inhibit chemoresistance and radioresistance and make cancer cells sensitive to these agents. Reports have further revealed the safety of the compound and the adaptation of nanotechnological approaches for improving its bioavailability.

SIGNIFICANCE

Hence, the present review recapitulates the properties of apigenin and its pharmacological activities against different types of cancer, which warrant further investigation in clinical settings.

Apigenin as Tumor Suppressor in Cancers: Biotherapeutic Activity, Nanodelivery, and Mechanisms With Emphasis on Pancreatic Cancer

Pancreatic cancer is the most lethal malignancy of the gastrointestinal tract. Due to its propensity for early local and distant spread, affected patients possess extremely poor prognosis. Currently applied treatments are not effective enough to eradicate all cancer cells, and minimize their migration. Besides, these treatments are associated with adverse effects on normal cells and organs. These therapies are not able to increase the overall survival rate of patients; hence, finding novel adjuvants or alternatives is so essential. Up to now, medicinal herbs were utilized for therapeutic goals. Herbal-based medicine, as traditional biotherapeutics, were employed for cancer treatment. Of them, apigenin, as a bioactive flavonoid that possesses numerous biological properties (e.g., anti-inflammatory and anti-oxidant effects), has shown substantial anticancer activity. It seems that apigenin is capable of suppressing the proliferation of cancer cells via the induction of cell cycle arrest and apoptosis. Besides, apigenin inhibits metastasis via down-regulation of matrix metalloproteinases and the Akt signaling pathway. In pancreatic cancer cells, apigenin sensitizes cells in chemotherapy, and affects molecular pathways such as the hypoxia inducible factor (HIF), vascular endothelial growth factor (VEGF), and glucose transporter-1 (GLUT-1). Herein, the biotherapeutic activity of apigenin and its mechanisms toward cancer cells are presented in the current review to shed some light on anti-tumor activity of apigenin in different cancers, with an emphasis on pancreatic cancer.

Dietary Polyphenols in Cancer Chemoprevention: Implications in Pancreatic Cancer

Naturally occurring dietary agents present in a wide variety of plant products, are rich sources of phytochemicals possessing medicinal properties, and thus, have been used in folk medicine for ages to treat various ailments. The beneficial effects of such dietary components are frequently attributed to their anti-inflammatory and antioxidant properties, particularly in regards to their antineoplastic activities. As many tumor types exhibit greater oxidative stress levels that are implicated in favoring autonomous cell growth activation, most chemotherapeutic agents can also enhance tumoral oxidative stress levels in part via generating reactive oxygen species (ROS). While ROS-mediated imbalance of the cellular redox potential can provide novel drug targets, as a consequence, this ROS-mediated excessive damage to cellular functions, including oncogenic mutagenesis, has also been implicated in inducing chemoresistance. This remains one of the major challenges in the treatment and management of human malignancies. Antioxidant-enriched natural compounds offer one of the promising approaches in mitigating some of the underlying mechanisms involved in tumorigenesis and metastasis, and therefore, have been extensively explored in cancer chemoprevention. Among various groups of dietary phytochemicals, polyphenols have been extensively explored for their underlying chemopreventive mechanisms in other cancer models. Thus, the current review highlights the significance and mechanisms of some of the highly studied polyphenolic compounds, with greater emphasis on pancreatic cancer chemoprevention.

Apigenin as an anticancer agent

Apigenin is an edible plant-derived flavonoid that has been reported as an anticancer agent in several experimental and biological studies. It exhibits cell growth arrest and apoptosis in different types of tumors such as breast, lung, liver, skin, blood, colon, prostate, pancreatic, cervical, oral, and stomach, by modulating several signaling pathways. Apigenin induces apoptosis by the activation of extrinsic caspase-dependent pathway by upregulating the mRNA expressions of caspase-3, caspase-8, and TNF-α. It induces intrinsic apoptosis pathway as evidenced by the induction of cytochrome c, Bax, and caspase-3, while caspase-8, TNF-α, and B-cell lymphoma 2 levels remained unchanged in human prostate cancer PC-3 cells. Apigenin treatment leads to significant downregulation of matrix metallopeptidases-2, -9, Snail, and Slug, suppressing invasion. The expressions of NF-κB p105/p50, PI3K, Akt, and the phosphorylation of p-Akt decreases after treatment with apigenin. However, apigenin-mediated treatment significantly reduces pluripotency marker Oct3/4 protein expression which might be associated with the downregulation of PI3K/Akt/NF-κB signaling.

Apigenin and Abivertinib, a novel BTK inhibitor synergize to inhibit diffuse large B-cell lymphoma in vivo and vitro

Background: Apigenin, a flavonoid phytochemical extracted from fruits and vegetables, has shown anti-neoplastic effects in a variety of malignant tumors. DLBCL is the most common type of aggressive lymphoma in adults with a poor prognosis. Small-molecule inhibitors like BTK inhibitors have demonstrated extended period of disease control. Whereas the effects of the synergetic inhibition of the two have not been elucidated.

Methods: We assessed the efficacy of Apigenin alone or combined with Abivertinib to inhibit DLBCL progression. Cell viability was examined using the cell proliferation cell proliferation assay (MTS). Apoptotic cells and cell cycle evaluation were detected by Annexin V-FITC and DNA staining solution respectively. Western blot was used to explore the potential mechanism, and the in vivo effects of the two drugs were performed by a DLBCL xenograft BALB/c nude mice model.

Results: Our results demonstrated that Apigenin can inhibit the proliferation and clone forming of DLBCL cells. Apigenin also induces apoptosis by down-regulating BCL-XL and activating Caspase family. In addition, Apigenin down-regulates cell cycle proteins including CDK2/CDK4/CDK6/CDC2/p-RB to increase G2/M phase arrest. Mechanically, our data demonstrate that Apigenin leads to a significant reduction of the expression of pro-proliferative pathway PI3K/mTOR to inhibit DLBCL cells survival. Moreover, our in vitro and in vivo results show that Apigenin can synergize with Abivertinib, a novel BTK inhibitor, in treating DLBCL visa synergistically inducing apoptosis and inhibiting the p-GS3K-β and its downstream targets.

Conclusions: Collectively, our study suggests that Apigenin exerts improving anti-lymphoma effect of BTK inhibitors and provides hope to targeted therapy of those develop resistance.

Ginsenoside Rk1 induces apoptosis and downregulates the expression of PD-L1 by targeting the NF-κB pathway in lung adenocarcinoma

Ginsenoside Rk1 can function as an antitumor modulator that induces apoptosis in lung adenocarcinoma cells by inhibiting NF-κB transcription and triggering cell cycle arrest.

A critical review on anti-angiogenic property of phytochemicals

Angiogenesis, a process involved in neovascularization, has been found to be associated with several metabolic diseases like cancer, retinopathy etc. Thus, currently, the focus on anti-angiogenic therapy for treatment and prevention of diseases has gained significant attention. Currently available Food and Drug Administration (FDA) approved drugs are targeting either vascular endothelial growth factor or it's receptor, but in the long term, these approaches were shown to cause several side effects and the chances of developing resistance to these drugs is also high. Therefore, identification of safe and cost-effective anti-angiogenic molecules is highly imperative. Over the past decades, dietary based natural compounds have been studied for their anti-angiogenic potential which provided avenues in improving the angiogenesis based therapy. In this review, major emphasis is given to the molecular mechanism behind anti-angiogenic effect of natural compounds from dietary sources.

Apigenin as an effective anticancer natural product: Spotlight on TRAIL, WNT/β-catenin, JAK-STAT pathways, and microRNAs

Wealth of information gleaned from decades of high-impact research work; scientists have disentangled the complicated web of versatile regulators that underlie cancer development and progression. Use of structural biology approaches and functional genomics have helped us to gain new insights into complex nature of cancer, and it is now clear that genetic/epigenetic mutations, overexpression of oncogenes, inactivation of tumor suppressors, loss of apoptosis, and versatility of protein binding partners have contributory roles in carcinogenesis and metastatic spread. It is becoming progressively more understandable that reprogramming of gene expression during and nontranscriptional changes during cancer development and progression are initiated and controlled by deregulated signal transduction cascades, all of which collectively create an incalculable complexity. Data obtained through preclinical and clinical trials revealed that alterations in the targeted oncogenes and other downstream, and parallel pathways played a central role in the development of resistance against different therapeutics. Phytochemicals have regained limelight, and different natural products are currently being tested for efficacy in preclinical studies. Apigenin, a plant-derived flavonoid has considerable pharmacological value and is reportedly involved in the regulation of different signaling cascades. In this review, we have attempted to summarize rapidly evolving understanding of molecular biologists and pharmacologists about the potential of apigenin in the regulation of deregulated signaling pathways in different cancers. We have emphasized on the regulation of WNT/β-catenin and janus kinase/signal transducers and activators of transcription (JAK-STAT) pathways. We also comprehensively discuss how apigenin restored apoptosis in tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-resistant cancers. The review also gives a snapshot of microRNAs (miRNAs) that regulate wide-ranging biological processes, and it is now clear that each miRNA can control hundreds of gene targets. Apigenin was noted to upregulate miR-520b and miR-101 in different cancers to inhibit tumor growth. Moreover, apigenin-induced apoptotic rate was significantly higher when used in combination with miR-423-5p inhibitors or miR-138 mimics. Better comprehension of linear and integrated signaling pathways will be helpful in effective therapeutic targeting of deregulated signaling pathways to inhibit/prevent cancer.

Apigenin Decreases Acinar Cell Damage in Pancreatitis

OBJECTIVE

Chronic pancreatitis is the consequence of multiple episodes of recurrent acute pancreatitis (RAP). We hypothesized that apigenin can minimize the sequelae of RAP by limiting acinar cells' proinflammatory signaling pathways.

METHODS

AR42J acinar cells were treated in vitro with transforming growth factor β (TGF-β), apigenin, and other inhibitors. Dual luciferase reporter assay measured parathyroid hormone-related protein (PTHrP) promoter activity. MAPK/ERK pathway activity was assessed by immunoblotting and in vivo by immunohistochemistry with a cerulein-induced RAP mouse model. Nuclear factor κ B nuclear localization was analyzed in vitro in cells stimulated with tumor necrosis factor α. Primary acini were isolated and treated with cerulein; interleukin 6 messenger RNA was measured comparing PTHrP wild-type and knockout mice.

RESULTS

Apigenin and PD98059 each downregulated TGF-β stimulation of PTHrP P3 promoter activity. In a RAP mouse model, apigenin reduced pERK nuclear localization in acinar cells and preserved acinar cell architecture. Apigenin suppressed tumor necrosis factor α-mediated signaling by decreasing nuclear factor κ B nuclear localization and decreased interleukin 6 messenger RNA levels via a PTHrP-dependent mechanism.

CONCLUSIONS

Apigenin reduced inflammatory responses in experimental models of RAP. The mechanisms mediating the actions of apigenin, in part, are owing to attenuation of PTHrP and TGF-β proinflammatory signaling.

Cancer Chemoprevention: Classic and Epigenetic Mechanisms Inhibiting Tumorigenesis. What Have We Learned So Far?

Cancers derive from step by step processes which are differentiated by the progressively accumulated mutations. For some tumors there is a clear progressive advancement from benign lesions to malignancy and for these, preventive screening programs exist. In such cases having those benign lesions are a clear indicator of predisposition while for some other cases, familial patterns of cancer incidence and the identification of mutations are the main indicators of higher risk for having the disease. For patients identified as having predisposition, chemoprevention is a goal and in some cases a possibility. Chemoprevention is the use of any compound, either natural or synthetic that abrogates carcinogenesis or tumor progression, through different mechanisms, some of which have already been described. For example, the classic mechanisms may involve activation of free radical scavenging enzymes, control of chronic inflammation, and downregulation of specific signaling pathways. More recently, epigenetics allowed further understanding of the chemopreventive potential of several agents, such as sulforaphane, green tea derived compounds, resveratrol, isoflavones, and others which we exploit in this review article. Throughout the text we discuss the properties compounds should have in order to be classified as chemopreventive ones and the challenges in translational research in this area, as lots of the success achieved in vitro cannot be translated into the clinical settings, due to several different drawbacks, which include toxicity, cost, dose definition, patient adherence, and regimen of use.

NF-κB in pancreatic cancer: Its key role in chemoresistance

Pancreatic cancer is considered a lethal disease with a high mortality and an extremely low five-year survival rate. Chemotherapy plays a pivotal role in pancreatic cancer treatment both in an adjuvant setting after complete resection and in the case of unresectable metastatic disease. However, none of the available combination chemotherapy regimens has resulted in satisfactory survival outcomes. Recent studies have revealed that both constitutive and induced activation of nuclear factor kappa B (NF-κB) in pancreatic cancer cells are closely associated with cell proliferation, invasion, anti-apoptosis, inflammation, angiogenesis and chemotherapeutic resistance. Therefore, NF-κB inhibitors in combination with cytotoxic compounds have been reported as novel agents that improve chemotherapy sensitivity in pancreatic cancer. In this review, we outline recent developments in the understanding of the role of the NF-κB signaling pathway and its associated genes in the progression of pancreatic cancer and highlight some potentially effective strategies for pancreatic cancer treatment.

Apigenin's anticancer properties and molecular mechanisms of action: Recent advances and future prospectives

Cancer is a major health concern and leading burden on economy worldwide. An increasing effort is devoted to isolation and development of plant-derived dietary components as effective chemo-preventive products. Phytochemical compounds from natural resources such as fruits and vegetables are responsible for decreasing the risk of certain cancers among the consuming populations. Apigenin, a flavonoid phytochemical found in many kinds of fruits and vegetables, has been shown to exert significant biological effects, such as anti-oxidant, anti-inflammatory and most particularly anti-neoplastic properties. This review is intended to summarize the most recent advances in the anti-proliferative and chemo-preventive effects of apigenin in different cancer models. Analysis of the data from the studied cancer models has revealed that apigenin exerts its anti-proliferative effects through multiple and complex pathways. This guided us to discover some controversial results about the exact role of certain molecular pathways such as autophagy in the anticancer effects of apigenin. Further, there were cumulative positive evidences supporting the involvement of certain pathways such as apoptosis, ROS and DNA damage and repair. Apigenin possesses a high potential to be used as a chemosensitizing agent through the up-regulation of DR5 pathway. According to these preclinical findings we recommend that further robust unbiased studies should consider the possible interactions between different molecular pathways.

Plant flavone apigenin: An emerging anticancer agent

Research in cancer chemoprevention provides convincing evidence that increased intake of vegetables and fruits may reduce the risk of several human malignancies. Phytochemicals present therein provide beneficial anti-inflammatory and antioxidant properties that serve to improve the cellular microenvironment. Compounds known as flavonoids categorized anthocyanidins, flavonols, flavanones, flavonols, flavones, and isoflavones have shown considerable promise as chemopreventive agents. Apigenin (4', 5, 7-trihydroxyflavone), a major plant flavone, possessing antioxidant, anti-inflammatory, and anticancer properties affecting several molecular and cellular targets used to treat various human diseases. Epidemiologic and case-control studies have suggested apigenin reduces the risk of certain cancers. Studies demonstrate that apigenin retain potent therapeutic properties alone and/or increases the efficacy of several chemotherapeutic drugs in combination on a variety of human cancers. Apigenin's anticancer effects could also be due to its differential effects in causing minimal toxicity to normal cells with delayed plasma clearance and slow decomposition in liver increasing the systemic bioavailability in pharmacokinetic studies. Here we discuss the anticancer role of apigenin highlighting its potential activity as a chemopreventive and therapeutic agent. We also highlight the current caveats that preclude apigenin for its use in the human trials.

Apigenin, by activating p53 and inhibiting STAT3, modulates the balance between pro-apoptotic and pro-survival pathways to induce PEL cell death

Background

Apigenin is a flavonoid widely distributed in plant kingdom that exerts cytotoxic effects against a variety of solid and haematological cancers. In this study, we investigated the effect of apigenin against primary effusion lymphoma (PEL), a KSHV-associated B cell lymphoma characterized by a very aggressive behavior, displaying constitutive activation of STAT3 as well as of other oncogenic pathways and harboring wtp53.

Methods

Cell death was assessed by trypan blue exclusion assay, FACS analysis as well as by biochemical studies. The latter were also utilized to detect the occurrence of autophagy and the molecular mechanisms leading to the activation of both processes by apigenin. FACS analysis was used to measure the intracellular ROS utilizing DCFDA.

Results

We show that apigenin induced PEL cell death and autophagy along with reduction of intracellular ROS. Mechanistically, apigenin activated p53 that induced catalase, a ROS scavenger enzyme, and inhibited STAT3, the most important pro-survival pathway in PEL, as assessed by p53 silencing. On the other hand, STAT3 inhibition by apigenin resulted in p53 activation, since STAT3 negatively influences p53 activity, highlighting a regulatory loop between these two pathways that modulates PEL cell death/survival.

Conclusion

The findings of this study demonstrate that apigenin may modulate pro-apoptotic and pro-survival pathways representing a valid therapeutic strategy against PEL.

In Vitro and In Vivo Anti-tumoral Effects of the Flavonoid Apigenin in Malignant Mesothelioma

Malignant mesothelioma (MM) is a tumor arising from mesothelium. MM patients’ survival is poor. The polyphenol 4′,5,7,-trihydroxyflavone Apigenin (API) is a “multifunctional drug”. Several studies have demonstrated API anti-tumoral effects. However, little is known on the in vitro and in vivo anti-tumoral effects of API in MM. Thus, we analyzed the in vitro effects of API on cell proliferation, cell cycle regulation, pro-survival signaling pathways, apoptosis, and autophagy of human and mouse MM cells. We evaluated the in vivo anti-tumor activities of API in mice transplanted with MM #40a cells forming ascites. API inhibited in vitro MM cells survival, increased reactive oxygen species intracellular production and induced DNA damage. API activated apoptosis but not autophagy. API-induced apoptosis was sustained by the increase of Bax/Bcl-2 ratio, increase of p53 expression, activation of both caspase 9 and caspase 8, cleavage of PARP-1, and increase of the percentage of cells in subG1 phase. API treatment affected the phosphorylation of ERK1/2, JNK and p38 MAPKs in a cell-type specific manner, inhibited AKT phosphorylation, decreased c-Jun expression and phosphorylation, and inhibited NF-κB nuclear translocation. Intraperitoneal administration of API increased the median survival of C57BL/6 mice intraperitoneally transplanted with #40a cells and reduced the risk of tumor growth. Our findings may have important implications for the design of MM treatment using API.

Design, synthesis, and biological evaluation of novel and analogs as potential IκB kinase β inhibitors for the treatment of pancreatic cancer

Given the important role that inhibitory kappa B (IκB) kinase β (IKKβ) plays in pancreatic cancer (PC) development and progression, inhibitors targeting IKKβ are believed to be increasingly popular as novel anti-PC therapies. Two synthetic molecules, named EF24 and EF31, exhibited favorable potential in terms of inhibition of both IKKβ activity and PC cell proliferation. Aiming to enhance their cellular efficacy and to analyze their structure–activity relationship, four series of EF24 and EF31 analogs were designed and synthesized. Through kinase activity and vitality screening of cancer cells, D6 displayed excellent inhibition of both IKKβ activity and PC cell proliferation. Additionally, multiple biological evaluations showed that D6 was directly bound to IKKβ and significantly suppressed the activation of the IKKβ/nuclear factor κB pathway induced by tumor necrosis factor-α, as well as effectively inducing cancer cell apoptosis. Moreover, molecular docking and molecular dynamics simulation analysis indicated that the dominant force between D6 and IKKβ comprised hydrophobic interactions. In conclusion, D6 may be a promising therapeutic agent for PC treatment and it also provides a structural lead for the design of novel IKKβ inhibitors.

Impact of Phytochemicals and Dietary Patterns on Epigenome and Cancer

Cancer remains one of the leading causes of death around the world. Initially it is recognized as a genetic disease, but now it is known to involve epigenetic abnormalities along with genetic alterations. Epigenetics refers to heritable changes that are not encoded in the DNA sequence itself, but play an important role in the control of gene expression. It includes changes in DNA methylation, histone modifications, and RNA interference. Although it is heritable, environmental factors such as diet could directly influence epigenetic mechanisms in humans. This article will focus on the role of dietary patterns and phytochemicals that have been demonstrated to influence the epigenome and more precisely histone and non-histone proteins modulation by acetylation that helps to induce apoptosis and phosphorylation inhibition, which counteracts with cells proliferation. Recent developments discussed here enhance our understanding of how dietary intervention could be beneficial in preventing or treating cancer and improving health outcomes.

Oxidative Stress Triggered by Apigenin Induces Apoptosis in a Comprehensive Panel of Human Cervical Cancer-Derived Cell Lines

Recently, the cytotoxic effects of apigenin (4′,5,7-trihydroxyflavone), particularly its marked inhibition of cancer cell viability both in vitro and in vivo, have attracted the attention of the anticancer drug discovery field. Despite this, there are few studies of apigenin in cervical cancer, and these studies have mostly been conducted using HeLa cells. To evaluate the possibility of apigenin as a new therapeutic candidate for cervical cancer, we evaluated its cytotoxic effects in a comprehensive panel of human cervical cancer-derived cell lines including HeLa (human papillomavirus/HPV 18-positive), SiHa (HPV 16-positive), CaSki (HPV 16 and HPV 18-positive), and C33A (HPV-negative) cells in comparison to a nontumorigenic spontaneously immortalized human epithelial cell line (HaCaT). Our results demonstrated that apigenin had a selective cytotoxic effect and could induce apoptosis in all cervical cancer cell lines which were positively marked with Annexin V, but not in HaCaT (control cells). Additionally, apigenin was able to induce mitochondrial redox impairment, once it increased ROS levels and H₂O₂, decreased the Δψm, and increased LPO. Still, apigenin was able to inhibit migration and invasion of cancer cells. Thus, apigenin appears to be a promising new candidate as an anticancer drug for cervical cancer induced by different HPV genotypes.

Apigenin potentiates TRAIL therapy of non-small cell lung cancer via upregulating DR4/DR5 expression in a p53-dependent manner

Apigenin (APG) is an edible plant-derived flavonoid that shows modest antitumor activities in vitro and in vivo. APG treatment results in cell growth arrest and apoptosis in various types of tumors by modulating several signaling pathways. In the present study, we evaluated interactions between APG and TRAIL in non-small cell lung cancer (NSCLC) cells. We observed a synergistic effect between APG and TRAIL on apoptosis of NSCLC cells. A549 cells and H1299 cells were resistant to TRAIL treatment alone. The presence of APG sensitized NSCLC cells to TRAIL-induced apoptosis by upregulating the levels of death receptor 4 (DR4) and death receptor 5 (DR5) in a p53-dependent manner. Consistently, the pro-apoptotic proteins Bad and Bax were upregulated, while the anti-apoptotic proteins Bcl-xl and Bcl-2 were downregulated. Meanwhile, APG suppressed NF-κB, AKT and ERK activation. Treatment with specific small-molecule inhibitors of these pathways enhanced TRAIL-induced cell death, mirroring the effect of APG. Furthermore, using a mouse xenograft model, we demonstrated that the combined treatment completely suppressed tumor growth as compared with APG or TRAIL treatment alone. Our results demonstrate a novel strategy to enhance TRAIL-induced antitumor activity in NSCLC cells by APG via inhibition of the NF-κB, AKT and ERK prosurvival regulators.

Targeting arachidonic acid pathway by natural products for cancer prevention and therapy

Arachidonic acid (AA) pathway, a metabolic process, plays a key role in carcinogenesis. Hence, AA pathway metabolic enzymes phospholipase A₂s (PLA₂s), cyclooxygenases (COXs) and lipoxygenases (LOXs) and their metabolic products, such as prostaglandins and leukotrienes, have been considered novel preventive and therapeutic targets in cancer. Bioactive natural products are a good source for development of novel cancer preventive and therapeutic drugs, which have been widely used in clinical practice due to their safety profiles. AA pathway inhibitory natural products have been developed as chemopreventive and therapeutic agents against several cancers. Curcumin, resveratrol, apigenin, anthocyans, berberine, ellagic acid, eugenol, fisetin, ursolic acid, [6]-gingerol, guggulsteone, lycopene and genistein are well known cancer chemopreventive agents which act by targeting multiple pathways, including COX-2. Nordihydroguaiaretic acid and baicalein can be chemopreventive molecules against various cancers by inhibiting LOXs. Several PLA₂s inhibitory natural products have been identified with chemopreventive and therapeutic potentials against various cancers. In this review, we critically discuss the possible utility of natural products as preventive and therapeutic agents against various oncologic diseases, including prostate, pancreatic, lung, skin, gastric, oral, blood, head and neck, colorectal, liver, cervical and breast cancers, by targeting AA pathway. Further, the current status of clinical studies evaluating AA pathway inhibitory natural products in cancer is reviewed. In addition, various emerging issues, including bioavailability, toxicity and explorability of combination therapy, for the development of AA pathway inhibitory natural products as chemopreventive and therapeutic agents against human malignancy are also discussed.

Apigenin blocks IKKα activation and suppresses prostate cancer progression

IKKα has been implicated as a key regulator of oncogenesis and driver of the metastatic process; therefore is regarded as a promising therapeutic target in anticancer drug development. In spite of the progress made in the development of IKK inhibitors, no potent IKKα inhibitor(s) have been identified. Our multistep approach of molecular modeling and direct binding has led to the identification of plant flavone apigenin as a specific IKKα inhibitor. Here we report apigenin, in micro molar range, inhibits IKKα kinase activity, demonstrates anti-proliferative and anti-invasive activities in functional cell based assays and exhibits anticancer efficacy in experimental tumor model. We found that apigenin directly binds with IKKα, attenuates IKKα kinase activity and suppresses NF-ĸB/p65 activation in human prostate cancer PC-3 and 22Rv1 cells much more effectively than IKK inhibitor, PS1145. We also showed that apigenin caused cell cycle arrest similar to knockdown of IKKα in prostate cancer cells. Studies in xenograft mouse model indicate that apigenin feeding suppresses tumor growth, lowers proliferation and enhances apoptosis. These effects correlated with inhibition of p-IKKα, NF-ĸB/p65, proliferating cell nuclear antigen and increase in cleaved caspase 3 expression in a dose-dependent manner. Overall, our results suggest that inhibition of cell proliferation, invasiveness and decrease in tumor growth by apigenin are mediated by its ability to suppress IKKα and downstream targets affecting NF-ĸB signaling pathways.

Activation of G-Protein-Coupled Estrogen Receptor Inhibits the Migration of Human Nonsmall Cell Lung Cancer Cells via IKK-β/NF-κB Signals

Estrogen signals have been suggested to modulate the progression and metastasis of nonsmall cell lung cancer (NSCLC), which is one of the leading causes of cancer deaths worldwide. While there are limited data concerning the roles and effects of G-protein-coupled estrogen receptor (GPER) on the progression of NSCLC, our present study reveals that the expression of GPER in NSCLC cells is obviously greater than that in lung fibroblast cell line MRC-5. Activation of GPER via its specific agonist G-1 decreases the in vitro motility of A549 and H358 cells and the expression of matrix metalloproteinase 2 (MMP-2) and MMP-9. Further, G-1 treatment can rapidly decrease the phosphorylation, nuclear translocation, and promoter activities of NF-κB in NSCLC cells. BAY 11-7082, the inhibitor of NF-κB, also inhibits the expression of MMP-2/9, while overexpression of p65 significantly attenuates G-1-induced downregulation of MMP-2/9. It suggests that inhibition of NF-κB mediates G-1-induced MMP-2/9 downregulation. G-1 treatment significantly down regulates the phosphorylation of IκB kinase β (IKK-β) and IκBα, while not IKK-α, in both 549 and H358 cells. ACHP, the specific inhibitor of IKK-β, can reinforce G-1-induced MMP-2/9 downregulation and invasion suppression of A549 cells. Collectively, our results suggest that activation of GPER can inhibit the migration of human NSCLC cells via suppression of IKK-β/NF-κB signals. These findings will help to better understand the roles and mechanisms of GPER as a potential therapy target for NSCLC patients.

Apigenin suppresses colorectal cancer cell proliferation, migration and invasion via inhibition of the Wnt/β-catenin signaling pathway

Abnormal activation of the Wnt/β-catenin signaling pathway has a significant role in human tumorigenesis. The search for potential anticancer drugs has included widespread screening of inhibitors of the Wnt signaling pathway. Recently, one of the most common flavonoids, apigenin, demonstrated potential anti-tumor effects on multiple human cancer cell lines, with low cytotoxicity and no mutagenic activity. However, the association between apigenin and the Wnt/β-catenin signaling pathway remains to be elucidated. The results of wound healing and Transwell invasion assays revealed that apigenin was able to significantly suppress colorectal cancer cell proliferation, migration and invasion in a dose-dependent manner. An organoid culture assay revealed that apigenin was also able to suppress the growth of intestinal organoids. Furthermore, apigenin inhibited β-catenin/T-cell factor/lymphoid enhancer factor signaling activation, which was induced by LiCl in a dose-dependent manner. This inhibited β-catenin nuclear entry, and therefore the expression of Wnt downstream target genes. In conclusion, apigenin significantly suppressed colorectal cancer cell proliferation, migration, invasion and organoid growth by inhibiting the Wnt/β-catenin signaling pathway.

An efficient liposome based method for antioxidants encapsulation

Apigenin is an antioxidant that has shown a preventive activity against different cancer and cardiovascular disorders. In this study, we encapsulate apigenin with liposome to tackle the issue of its poor bioavailability and low stability. Apigenin loaded liposomes are fabricated with food-grade rapeseed lecithin in an aqueous medium in absence of any organic solvent. The liposome particle characteristics, such as particle size and polydispersity are optimised by tuning ultrasonic processing parameters. In addition, to measure the liposome encapsulation efficiency accurately, we establish a unique high-performance liquid chromatography technique in which an alkaline buffer mobile phase is used to prevent apigenin precipitation in the column;. salt is added to separate lipid particles from the aqeuous phase. Our results demonstrate that apigenin encapsulation efficiency is nearly 98% that is remarkably higher than any other reported value for encapsulation of this compound. In addition, the average particle size of these liposomes is 158.9 ± 6.1 nm that is suitable for the formulation of many food products, such as fortified fruit juice. The encapsulation method developed in this study, therefore have a high potential for the production of innovative, functional foods or nutraceutical products.

Apigenin Inhibits Tumor Necrosis Factor-α-Induced Production and Gene Expression of Mucin through Regulating Nuclear Factor-Kappa B Signaling Pathway in Airway Epithelial Cells

In the present study, we investigated whether apigenin significantly affects tumor necrosis factor-α (TNF-α)-induced production and gene expression of MUC5AC mucin in airway epithelial cells. Confluent NCI-H292 cells were pretreated with apigenin for 30 min and then stimulated with TNF-α for 24 h or the indicated periods. The MUC5AC mucin gene expression and mucin protein production were measured by reverse transcription - polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. Apigenin significantly inhibited MUC5AC mucin production and down-regulated MUC5AC gene expression induced by TNF-α in NCI-H292 cells. To elucidate the action mechanism of apigenin, effect of apigenin on TNF-α-induced nuclear factor kappa B (NF-κB) signaling pathway was also investigated by western blot analysis. Apigenin inhibited NF-κB activation induced by TNF-α. Inhibition of inhibitory kappa B kinase (IKK) by apigenin led to the suppression of inhibitory kappa B alpha (IκBα) phosphorylation and degradation, p65 nuclear translocation. This, in turn, led to the down-regulation of MUC5AC protein production in NCI-H292 cells. Apigenin also has an influence on upstream signaling of IKK because it inhibited the expression of adaptor protein, receptor interacting protein 1 (RIP1). These results suggest that apigenin can regulate the production and gene expression of mucin through regulating NF-κB signaling pathway in airway epithelial cells.