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

Leveraging a Y. lipolytica naringenin chassis for biosynthesis of apigenin and associated glucoside

Flavonoids are a diverse set of natural products with promising bioactivities including anti-inflammatory, anti-cancer, and neuroprotective properties. Previously, the oleaginous host Yarrowia lipolytica has been engineered to produce high titers of the base flavonoid naringenin. Here, we leverage this host along with a set of E. coli bioconversion strains to produce the flavone apigenin and its glycosylated derivative isovitexin, two potential nutraceutical and pharmaceutical candidates. Through downstream strain selection, co-culture optimization, media composition, and mutant isolation, we were able to produce168 mg/L of apigenin, representing a 46% conversion rate of 2-(R/S)-naringenin to apigenin. This apigenin platform was modularly extended to produce isovitexin by addition of a second bioconversion strain. Together, these results demonstrate the promise of microbial production and modular bioconversion to access diversified flavonoids.

Apigenin and its combination with Vorinostat induces apoptotic-mediated cell death in TNBC by modulating the epigenetic and apoptotic regulators and related miRNAs

Triple-negative breast cancer (TNBC) is a metastatic disease and a formidable treatment challenge as it does not respond to existing therapies. Epigenetic regulators play a crucial role in the progression and metastasis by modulating the expression of anti-apoptotic, pro-apoptotic markers and related miRNAs in TNBC cells. We have investigated the anti-TNBC potential of dietary flavonoid 'Apigenin' and its combination with Vorinostat on MDA-MB-231 cells. At Apigenin generated ROS, inhibited cell migration, arrested the cell cycle at subG0/G1 phases, and induced apoptotic-mediated cell death. Apigenin reduced the expression of the class-I HDACs at the transcriptomic and proteomic levels. In the immunoblotting study, Apigenin has upregulated pro-apoptotic markers and downregulated anti-apoptotic proteins. Apigenin inhibited the enzymatic activity of HDAC/DNMT and increased HAT activity. Apigenin has manifested its effect on miRNA expression by upregulating the tumor-suppressor miR-200b and downregulation oncomiR-21. Combination study reduced the growth of TNBC cells synergistically by modulating the expression of epigenetic and apoptotic regulators. Molecular docking and MD simulations explored the mechanism of catalytic inhibition of HDAC1 and HDAC3 and supported the in-vitro studies. The overall studies demonstrated an anti-TNBC potential of Apigenin and may help to design an effective strategy to treat metastatic phenotype of TNBC.

Protective Effects of Alpha-lipoic Acid, Resveratrol, and Apigenin Against Oxidative Damages, Histopathological Changes, and Mortality Induced by Lung Irradiation in Rats

AIM

This study investigated the protective effects of three antioxidants on radiationinduced lung injury.

BACKGROUND

Oxidative stress is one of the key outcomes of radiotherapy in normal tissues. It can induce severe injuries in lung tissue, which may lead to pneumonitis and fibrosis. Recently, interest in natural chemicals as possible radioprotectors has increased due to their reduced toxicity, cheaper price, and other advantages.

OBJECTIVE

The present study was undertaken to evaluate the radioprotective effect of Alpha-lipoic Acid (LA), Resveratrol (RVT), and Apigenin (APG) against histopathological changes and oxidative damage and survival induced by ionizing radiation (IR) in the lung tissues of rats.

METHODS

First, the lung tissue of 50 mature male Wistar rats underwent an 18 Gy gamma irradiation. Next, the rats were sacrificed and transverse sections were obtained from the lung tissues and stained with hematoxylin and eosin (H and E) and Mason trichrome (MTC) for histopathological evaluation. Then, the activity of Glutathione peroxidase (GPx), Superoxide Dismutase (SOD), and Malondialdehyde (MDA) was measured by an ELISA reader at 340, 405, and 550 nm.

RESULTS

Based on the results of this study, IR led to a remarkable increase in morphological changes in the lung. However, APG, RVT, and LA could ameliorate the deleterious effects of IR in lung tissue. IR causes an increase in GPX level, and APG+IR administration causes a decrease in the level of GPX compared to the control group. Also, the results of this study showed that RVT has significant effects in reducing MDA levels in the short term. In addition, compared to the control group, IR and RVT+IR decrease the activity of SOD in the long term in the lung tissues of rats. Also, the analysis of results showed that weight changes in IR, LA+IR, APG+IR, and control groups were statistically significant.

CONCLUSION

APG and RVT could prevent tissue damage induced by radiation effects in rat lung tissues. Hence, APG, LA, and RVT could provide a novel preventive action with their potential antioxidant anti-inflammatory properties, as well as their great safety characteristic.

Flavonoids as promising molecules in the cancer therapy: An insight

Cancer continues to increase global morbidity and mortality rates. Despite substantial progress in the development of various chemically synthesized anti-cancer drugs, the poor prognosis of the disease still remains a big challenge. The most common drawback of conventional cancer therapies is the emergence of drug resistance eventually leading to the discontinuation of chemotherapy. Moreover, advanced target-specific therapies including immunotherapy and stem cell therapy are expensive enough and are unaffordable for most patients in poorer nations. Therefore, alternative and cheaper therapeutic strategies are needed to complement the current cancer treatment approaches. Phytochemicals are bioactive compounds produced naturally by plants and have great potential in human health and disease. These compounds possess antiproliferative, anti-oxidant, and immunomodulatory properties. Among the phytochemicals, flavonoids are very effective in treating a wide range of diseases from cardiovascular diseases and immunological disorders to cancer. They scavenge reactive oxygen species (ROS), inhibit cancer metastasis, modulate the immune system and induce apoptotic or autophagic cell death in cancers. This review will discuss the potential of various phytochemicals particularly flavonoids in attempts to target various cancers.

Determination of Rutin's antitumoral effect on EAC solid tumor by AgNOR count and PI3K/AKT/mTOR signaling pathway

Rutin is one of the flavonoids found in fruits and vegetables. The PI3K/AKT/mTOR signaling pathway is critical for the life cycle at the cellular level. In current study, we purposed to demonstrate the antitumoral effect of rutin at different doses through the mTOR-signaling pathway and argyrophilic nucleolar regulatory region. EAC cells were injected subcutaneously into the experimental groups. 25 and 50 mg/kg Rutin were injected intraperitoneally to the animals with solid tumors for 14 days. Immunohistochemical, Real-time PCR and AgNOR analyzes were actualized on the taken tumors. When the rutin given groups and the tumor group were compared, the tumor size increase was detected to be statistically significant (p < 0.05). In immunohistochemical analysis, a significant decrease was encountered in the AKT, mTOR, PI3K and F8 expressions especially in the groups administered 25 mg Rutin, in comparison with the control group (p < 0.05). AgNOR area/nuclear area (TAA/NA) and average AgNOR number were determineted, and statistically important differences were detected between the groups in terms of TAA/NA ratio (p < 0.05). There were significant statistical differences between the mRNA quantity of the PI3K, AKT1 and mTOR genes (p < 0.05). In the in vitro study, cell apoptosis was evaluated with different doses of annexin V and it was determined that a dose of 10 µg/mL Rutin induced apoptosis (p < 0.05). In our study, it was demonstrated in vivo and in vitro that Rutin has an anti-tumor effect on the development of solid tumors formed by both EAC cells.

Modulation of AKT Pathway-Targeting miRNAs for Cancer Cell Treatment with Natural Products

Many miRNAs are known to target the AKT serine-threonine kinase (AKT) pathway, which is critical for the regulation of several cell functions in cancer cell development. Many natural products exhibiting anticancer effects have been reported, but their connections to the AKT pathway (AKT and its effectors) and miRNAs have rarely been investigated. This review aimed to demarcate the relationship between miRNAs and the AKT pathway during the regulation of cancer cell functions by natural products. Identifying the connections between miRNAs and the AKT pathway and between miRNAs and natural products made it possible to establish an miRNA/AKT/natural product axis to facilitate a better understanding of their anticancer mechanisms. Moreover, the miRNA database (miRDB) was used to retrieve more AKT pathway-related target candidates for miRNAs. By evaluating the reported facts, the cell functions of these database-generated candidates were connected to natural products. Therefore, this review provides a comprehensive overview of the natural product/miRNA/AKT pathway in the modulation of cancer cell development.

Role of STAT3 in the initiation, progression, proliferation and metastasis of breast cancer and strategies to deliver JAK and STAT3 inhibitors

INTRODUCTION

Breast cancer (BC) accounts for the majority of cancers among the female population. Anomalous activation of various signaling pathways has become an issue of concern. The JAK-STAT signaling pathway is activated in numerous cancers, including BC. STAT3 is widely involved in BCs, as 40 % of BCs display phosphorylated STAT3. JAK-STAT signaling is crucial for proliferation, survival, metastasis and other cellular events associated with the tumor microenvironment. Hence, targeting this pathway has become an area of interest among researchers.

KEY FINDINGS

This review article focuses on the role of STAT3 in the initiation, proliferation, progression and metastasis of BC. The roles of various phytochemicals, synthetic molecules and biologicals against JAK-STAT and STAT3 in various cancers have been discussed, with special emphasis on BC.

SIGNIFICANCE

JAK and STAT3 are involved in various phases from initiation to metastasis, and targeting this pathway is a promising approach to inhibit the various stages of BC development and to prevent metastasis. A number of phytochemicals and synthetic and biological molecules have demonstrated potential inhibitory effects on JAK and STAT3, thereby paving the way for the development of better therapeutics against BC.

Therapeutic Potential of Naturally Occurring Small Molecules to Target the Wnt/β-Catenin Signaling Pathway in Colorectal Cancer

Simple Summary

Colorectal cancer (CRC) is an emerging public health problem and the second leading cause of death worldwide, with a significant socioeconomic impact in several countries. The 5-year survival rate is only 12% due to the lack of early diagnosis and resistance to available treatments, and the canonical Wnt signaling pathway is involved in this process. This review underlines the importance of understanding the fundamental roles of this pathway in physiological and pathological contexts and analyzes the use of naturally occurring small molecules that inhibits the Wnt/β-catenin pathway in experimental models of CRC. We also discuss the progress and challenges of moving these small molecules off the laboratory bench into the clinical platform.

Abstract

Colorectal cancer (CRC) ranks second in the number of cancer deaths worldwide, mainly due to late diagnoses, which restrict treatment in the potentially curable stages and decrease patient survival. The treatment of CRC involves surgery to remove the tumor tissue, in addition to radiotherapy and systemic chemotherapy sessions. However, almost half of patients are resistant to these treatments, especially in metastatic cases, where the 5-year survival rate is only 12%. This factor may be related to the intratumoral heterogeneity, tumor microenvironment (TME), and the presence of cancer stem cells (CSCs), which is impossible to resolve with the standard approaches currently available in clinical practice. CSCs are APC-deficient, and the search for alternative therapeutic agents such as small molecules from natural sources is a promising strategy, as these substances have several antitumor properties. Many of those interfere with the regulation of signaling pathways at the central core of CRC development, such as the Wnt/β-catenin, which plays a crucial role in the cell proliferation and stemness in the tumor. This review will discuss the use of naturally occurring small molecules inhibiting the Wnt/β-catenin pathway in experimental CRC models over the past decade, highlighting the molecular targets in the Wnt/β-catenin pathway and the mechanisms through which these molecules perform their antitumor activities.

Facilitating Reparative Dentin Formation Using Apigenin Local Delivery in the Exposed Pulp Cavity

Apigenin, a natural product belonging to the flavone class, affects various cell physiologies, such as cell signaling, inflammation, proliferation, migration, and protease production. In this study, apigenin was applied to mouse molar pulp after mechanically pulpal exposure to examine the detailed function of apigenin in regulating pulpal inflammation and tertiary dentin formation. In vitro cell cultivation using human dental pulp stem cells (hDPSCs) and in vivo mice model experiments were employed to examine the effect of apigenin in the pulp and dentin regeneration. In vitro cultivation of hDPSCs with apigenin treatment upregulated bone morphogenetic protein (BMP)- and osteogenesis-related signaling molecules such as BMP2, BMP4, BMP7, bone sialoprotein (BSP), runt-related transcription factor 2 (RUNX2), and osteocalcin (OCN) after 14 days. After apigenin local delivery in the mice pulpal cavity, histology and cellular physiology, such as the modulation of inflammation and differentiation, were examined using histology and immunostainings. Apigenin-treated specimens showed period-altered immunolocalization patterns of tumor necrosis factor (TNF)-α, myeloperoxidase (MPO), NESTIN, and transforming growth factor (TGF)-β1 at 3 and 5 days. Moreover, the apigenin-treated group showed a facilitated dentin-bridge formation with few irregular tubules after 42 days from pulpal cavity preparation. Micro-CT images confirmed obvious dentin-bridge structures in the apigenin-treated specimens compared with the control. Apigenin facilitated the reparative dentin formation through the modulation of inflammation and the activation of signaling regulations. Therefore, apigenin would be a potential therapeutic agent for regenerating dentin in exposed pulp caused by dental caries and traumatic injury.

Rutin (Bioflavonoid) as Cell Signaling Pathway Modulator: Prospects in Treatment and Chemoprevention

Cancer is a complex ailment orchestrated by numerous intrinsic and extrinsic pathways. Recent research has displayed a deep interest in developing plant-based cancer therapeutics for better management of the disease and limited side effects. A wide range of plant-derived compounds have been reported for their anticancer potential in the quest of finding an effective therapeutic approach. Rutin (vitamin P) is a low-molecular weight flavonoid glycoside (polyphenolic compound), abundantly present in various vegetables, fruits (especially berries and citrus fruits), and medicinal herbs. Numerous studies have delineated several pharmacological properties of rutin such as its antiprotozoal, antibacterial, anti-inflammatory, antitumor, antiviral, antiallergic, vasoactive, cytoprotective, antispasmodic, hypolipidemic, antihypertensive, and antiplatelet properties. Specifically, rutin-mediated anticancerous activities have been reported in several cancerous cell lines, but the most common scientific evidence, encompassing several molecular processes and interactions, including apoptosis pathway regulation, aberrant cell signaling pathways, and oncogenic genes, has not been thoroughly studied. In this direction, we attempted to project rutin-mediated oncogenic pathway regulation in various carcinomas. Additionally, we also incorporated advanced research that has uncovered the notable potential of rutin in the modulation of several key cellular functions via interaction with mRNAs, with major emphasis on elucidating direct miRNA targets of rutin as well as the process needed to transform these approaches for developing novel therapeutic interventions for the treatment of several cancers.

Pharmacological Effects of Polyphenol Phytochemicals on the JAK-STAT Signaling Pathway

The JAK-STAT signaling pathway is a common pathway of many cytokine signal transductions, closely related to cell proliferation, apoptosis, differentiation, and inflammatory response. It is essential for inhibiting the inflammatory response, initiating innate immunity, and coordinating adaptive immune mechanisms. Owing to the nature of this pathway and its potential cross-epitopes with multiple alternative pathways, the long-term efficacy of monotherapy-based adaptive targeting therapy is limited, and the majority of drugs targeting STATs are still in the preclinical phase. Meanwhile, curcumin, quercetin, and several kinds of plant polyphenol chemicals play roles in multiple sites of the JAK-STAT pathway to suppress abnormal activation. Polyphenol compounds have shown remarkable effects by acting on the JAK-STAT pathway in anti-inflammatory, antitumor, and cardiovascular disease control. This review summarizes the pharmacological effects of more than 20 kinds of phytochemicals on JAK-STAT signaling pathway according to the chemical structure of polyphenolic phytochemicals.

Dehydrocrenatidine inhibits head and neck cancer cells invasion and migration by modulating JNK1/2 and ERK1/2 pathway and decreases MMP-2 expression

Head and neck cancer is associated with poor prognosis because of its highly metastatic nature. For the better management of head and neck cancer patients, it is very important to diagnose the cancer at an early stage, as well as to prevent the rapid spread of cancer either through direct invasion or lymphatic metastasis. In present study, the effect of dehydrocrenatidine, which is a beta-carboline alkaloid found in the medicinal plant Picrasma quassioides, on human head and neck cancer metastasis was investigated. The study results revealed the treatment of FaDu, SCC9, and SCC47 cells with 5, 10, and 20 μM of dehydrocrenatidine significantly decreased the motility, migration, and invasion of head and neck cancer cells. Moreover, the dehydrocrenatidine treatment significantly decreased the expression of MMP-2 and phosphorylation of ERK1/2 and JNK1/2. Additional experiments revealed that the cotreatment of dehydrocrenatidine with either ERK1/2 or JNK1/2 inhibitor caused further reduction in cancer cell motility and migration compared to that in dehydrocrenatidine treatment alone. Moreover, similar trend was observed in case of ERK1/2 and JNK1/2 phosphorylation and MMP-2 expression after the cotreatment. Taken together, the mechanism by which dehydrocrenatidine can decrease the phosphorylation of ERK1/2 and JNK1/2, follow decrease the expression of MMP-2 and inhibits head and neck cancer cells invasion and migration. This present study identifies dehydrocrenatidine as a potent antimetastatic agent that can be used clinically to improve head and neck cancer prognosis.

Realizing the Potential of Blueberry as Natural Inhibitor of Metastasis and Powerful Apoptosis Inducer: Tapping the Treasure Trove for Effective Regulation of Cell Signaling Pathways

Blueberries belong to the genus Vaccinium of the family Ericaceae. Rapidly accumulating experimentally verified data is uncovering the tremendous pharmacological properties of biologically active constituents of blueberries against different diseases. Our rapidly evolving knowledge about the multifaceted nature of cancer has opened new horizons to search for different strategies to target multiple effectors of oncogenic networks to effectively inhibit cancer onset and progression. Excitingly, whole blueberry powder and various bioactive constituents (pterostilbene, malvidin-3-galactoside) of blueberries have been shown to efficiently inhibit metastasis in animal models. These results are encouraging and future studies must focus on the identification of cell signaling pathways effectively modulated by blueberries in different cancers. It seems exciting to note that researchers are focusing on metastasis inhibitory effects of blueberry; however, to reap full benefits, it is necessary to take a step back and critically re-interpret the mechanisms used by active components of blueberry to inhibit or prevent metastasis. JAK/STAT, TGF/SMAD, Notch, SHH/GLI, and Wnt/ β-Catenin have been shown to be directly involved in the regulation of metastasis. However, because of limited studies, it is difficult to critically assess the true potential of blueberry. Loss of apoptosis, metastasis and deregulation of signaling pathways are branching trajectories of molecular oncology. Accordingly, we have to emphasize on these essential facets to realistically claim blueberry as "Superfood". Different clinical trials have been conducted to gather clinical evidence about the chemopreventive role of blueberry or its bioactive components in cancer patients. But it seems clear that because of the lack of sufficient proof-of-concept studies, we cannot extract significant information about the transition of blueberry into the next phases of clinical trials. Overview of the existing scientific evidence revealed visible knowledge gaps and a better understanding of the targets of blueberry will be helpful in efficient and meaningful translation of laboratory findings to clinically effective therapeutics.

Flavonoids Overcome Drug Resistance to Cancer Chemotherapy by Epigenetically Modulating Multiple Mechanisms

Drug resistance is the major reason accounting for the treatment failure in cancer chemotherapy. Dysregulation of the epigenetic machineries is known to induce chemoresistance. It was reported that numerous genes encoding the key mediators in cancer proliferation, apoptosis, DNA repair, and drug efflux are dysregulated in resistant cancer cells by aberrant DNA methylation. The imbalance of various enzymes catalyzing histone post-translational modifications is also known to alter chromatin configuration and regulate multiple drug resistance genes. Alteration in miRNA signature in cancer cells also gives rise to chemoresistance. Flavonoids are a large group of naturally occurring polyphenolic compounds ubiquitously found in plants, fruits, vegetables and traditional herbs. There has been increasing research interest in the health-promoting effects of flavonoids. Flavonoids were shown to directly kill or re-sensitize resistant cancer cells to conventional anticancer drugs by epigenetic mechanisms. In this review, we summarize the current findings of the circumvention of drug resistance by flavonoids through correcting the aberrant epigenetic regulation of multiple resistance mechanisms. More investigations including the evaluation of synergistic anticancer activity, dosing sequence effect, toxicity in normal cells, and animal studies, are warranted to establish the full potential of the combination of flavonoids with conventional chemotherapeutic drugs in the treatment of cancer with drug resistance.

Rotundic Acid Regulates the Effects of Let-7f-5p on Caco2 Cell Proliferation

BACKGROUND & OBJECTIVE

Nowadays, the interaction between natural products and microRNAs provides a promising field for exploring the chemopreventive agents for various cancers. As a member of microRNAs, the expression of let-7f-5p is universally downregulated in Colorectal Cancer (CRC). The present study aimed to uncover the function of let-7f-5p in the proliferation of human colon cancer cell line Caco2 and explored chemopreventive agents from natural resources that can prevent the development of CRC.

METHODS

Herein, Caco2 cells were transfected with let-7f-5p mimic and inhibitor to manipulate let-7f-5p levels, and the expression of let-7f-5p was performed by RT-qPCR. Next, we determined how let-7f-5p regulates Caco2 cell proliferation by using MTT, wound-healing, cell cycle, and colony formation assays. Besides, to further understand the effect of let-7f-5p, we evaluated the protein level of AMER3 and SLC9A9 by using western blotting assays.

RESULTS

The results showed a suppressive function of let-7f-5p on Caco2 cell proliferation and then put forward a triterpenoid (Rotundic Acid, RA) which significant antagonized the effect of cell proliferation, restitution after wounding, and colony formation caused by let-7f-5p. Moreover, the western blot results further indicated that the inhibitory effect of RA might be due to its suppressive role in let-7f-5p-targeted AMER3 and SLC9A9 regulation.

CONCLUSION

Our validation study results confirmed that let-7f-5p was a potent tumor suppressor gene of Caco2 cell proliferation, and RA showed as a regulator of the effect of let-7f-5p on cell proliferation and then could be a potential chemopreventive agent for CRC treatment.

Apigenin role as cell-signaling pathways modulator: implications in cancer prevention and treatment

Cancer is a complex disease orchestrated by various extrinsic and intrinsic pathways. In recent years, there has been a keen interest towards the development of natural extracts-based cancer therapeutics with minimum adverse effects. In pursuit of effective strategy, a wide variety of natural products-derived compounds have been addressed for their anticancer effects. Apigenin is a naturally-occurring flavonoid present abundantly in various fruits and vegetables. Decades of research have delineated the pharmacological and biological properties of apigenin. Specifically, the apigenin-mediated anticancer activities have been documented in various types of cancer, but the generalized scientific evidence encompassing various molecular interactions and processes, such as regulation of the apoptotic machinery, aberrant cell signaling and oncogenic protein network have not been comprehensively covered. In this sense, in this review we have attempted to focus on the apigenin-mediated regulation of oncogenic pathways in various cancers. We have also addressed the cutting-edge research which has unveiled the remarkable abilities of apigenin to interact with microRNAs to modulate key cellular processes, with special emphasis on the nano-formulations of apigenin that can help their targeted delivery and can be a therapeutic solution for the treatment of various cancers.

Genetic alterations in Wnt family of genes and their putative association with head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is the most frequent type of head and neck cancer that usually arises from the mucosal surfaces of several organs including nasal cavity, paranasal sinuses, oral cavity, tongue, pharynx, and larynx. The Wnt signaling pathway is a crucial mechanism for cellular maintenance and development. It regulates cell cycle progression, apoptosis, proliferation, migration, and differentiation. Dysregulation of this pathway correlates with oncogenesis in various tissues including breast, colon, pancreatic as well as head and neck cancers. The present study aims to assess the gene alterations in the Wnt family of genes so as to derive an association with HNSCC. Computational approaches have been utilized for the identification of gene alterations in the Wnt family of genes. Several databases such as cBioportal, STRING, and UALCAN were used for the purpose. The frequency of alteration was high in case of Wnt family member 11 (5%). Gene amplification, deep deletions, missense and truncating mutations were observed in HNSCC patients. There was a marked difference in the gene expression profile of WNT11 between grades as well as normal samples. The survival probability measured using the Kaplan-Meier curve also presented with a significant difference among male and female subjects experiencing a low/medium level expression. The female patients showed less survival probability when compared to the male subjects. This provides the prognostic significance of the WNT11 gene in HNSCC. Taken together, the present study provides clues on the possible association of WNT11 gene alterations with HNSCC, which has to be further validated using experimental approaches.

Apigenin suppresses TGF-β1-induced cardiac fibroblast differentiation and collagen synthesis through the downregulation of HIF-1α expression by miR-122-5p

BACKGROUND

Apigenin can reduce cardiomyocyte hypertrophy by downregulating hypoxia inducible factor-1 alpha (HIF-1α) expression. However, its effects on cardiac fibroblasts (CFs) and its exact inhibitory molecular mechanisms on HIF-1α remain unclear.

PURPOSE

This study aims to examine the effects of apigenin on cell proliferation and differentiation, microRNA-122-5p (miR-122-5p) expression, and HIF-1α-mediated Smad signaling pathway in transforming growth factor beta 1 (TGF-β1)-stimulated CFs and cardiac fibrosis and to investigate the relationship between miR-122-5p and HIF-1α.

METHODS

The TGF-β1-stimulated CFs, the combination of TGF-β1-stimulated and miR-122-5p mimic-transfected CFs, the combination of TGF-β1-stimulated and miR-122-5p inhibitor-transfected CFs, and the isoproterenol-induced cardiac fibrotic mice were used and treated with or without apigenin. The recombinant lentiviruses overexpressing HIF-1α vector and miR-122-5p mimic were co-transfected to observe their interaction. Related mRNA and protein expressions and myocardial collagen were determined. The luciferase reporter gene that contains HIF-1α wild type or mutant type 3'-UTR was used, and the luciferase activity was determined to verify the direct link between miR-122-5p and HIF-1α.

RESULTS

In the TGF-β1-stimulated CFs, apigenin treatment increased the miR-122-5p and Smad7 expressions and decreased the HIF-1α, α-smooth muscle actin, collagen Ⅰ/Ⅲ, Smad2/3, and p-Smad2/3 expressions. Similar and inverse results were observed in the miR-122-5p mimic- and inhibitor-transfected CFs, respectively. Moreover, the miR-122-5p mimic could antagonize the effects of TGF-β1 in the TGF-β1 and miR-122-5p mimic-combined CFs, and the miR-122-5p inhibitor could enhance the effects of TGF-β1 in the TGF-β1 and miR-122-5p inhibitor-combined CFs. In the two aforementioned cell models, the addition of apigenin could further enhance the effects of miR-122-5p mimic and partially reverse the effects of miR-122-5p inhibitor. After treatment of HIF-1α-transfected CFs with miR-122-5p mimic, the HIF-1α expression decreased. Further study confirmed that HIF-1α was a direct target of miR-122-5p. Apigenin also decreased the myocardial collagen accumulation in cardiac fibrotic mice.

CONCLUSION

Apigenin could suppress the differentiation and collagen synthesis of TGF-β1-stimulated CFs and mouse cardiac fibrosis, and its mechanisms were related to the increment of miR-122-5p expression and subsequent downregulation of HIF-1α expression via direct interaction, which might finally result in the decrements of Smad2/3 and p-Smad2/3 expressions and increment of Smad7 expression.

Natural products in the reprogramming of cancer epigenetics

Owing to the technological advancements, including next generation sequencing, the significance of deregulated epigenetic mechanisms in cancer initiation, progression and treatment has become evident. The accumulating knowledge relating to the epigenetic markers viz. DNA methylation, Histone modifications and non-coding RNAs make them one of the most interesting candidates for developing anti-cancer therapies. The reversibility of deregulated epigenetic mechanisms through environmental and dietary factors opens numerous avenues in the field of chemoprevention and drug development. Recent studies have proven that plant-derived natural products encompass a great potential in targeting epigenetic signatures in cancer and numerous natural products are being explored for their possibility to be considered as "epi-drug". This review intends to highlight the major aberrant epigenetic mechanisms and summarizes the essential functions of natural products like Resveratrol, Quercetin, Genistein, EGCG, Curcumin, Sulforaphane, Apigenin, Parthenolide and Berberine in modulating these aberrations. This knowledge along with the challenges and limitations in this field has potential and wider implications in developing novel and successful therapeutic strategies. The increased focus in the area will possibly provide a better understanding for the development of dietary supplements and/or drugs either alone or in combination. The interaction of epigenetics with different hallmarks of cancer and how natural products can be utilized to target them will also be interesting in the future therapeutic approaches.

Apigenin attenuates TGF-β1-stimulated cardiac fibroblast differentiation and extracellular matrix production by targeting miR-155-5p/c-Ski/Smad pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Apigenin is a natural flavonoid compound present in chamomile (Matricaia chamomilla L.) from the Asteraceae family, which is used in the treatment of cardiovascular diseases by traditional healers, but its effects on differentiation and extracellular matrix (ECM) production of cardiac fibroblasts (CFs) induced by transforming growth factor beta 1 (TGF-β1) are poorly understood.

AIM OF THE STUDY

This study aimed to examine these effects and potential molecular mechanisms and to provide a new application of apigenin in the prevention and treatment of cardiac fibrosis.

MATERIALS AND METHODS

The TGF-β1-stimulated CFs or the combination of TGF-β1-stimulated and microRNA-155-5p (miR-155-5p) inhibitor- or mimic-transfected CFs were treated with or without apigenin. The expression levels of intracellular related mRNA and proteins were detected by real-time polymerase chain reaction and Western blot methods, respectively. The luciferase reporter gene containing cellular Sloan-Kettering Institute (c-Ski) wild or mutant type 3'-UTR was used and the luciferase activity was examined to verify the direct link of miR-155-5p and c-Ski.

RESULTS

After treatment of TGF-β1-stimulated CFs with 6-24 μM apigenin, the expression of c-Ski was increased, while levels of miR-155-5p, α-smooth muscle actin, collagen Ⅰ/Ⅲ, Smad2/3, and p-Smad2/3 were decreased. After transfection of CFs with the miR-155-5p inhibitor or mimic, the similar or inverse results were respectively observed as well. The combination of TGF-β1 and miR-155-5p inhibitor or mimic might cause an antagonistical or synergistic effect, respectively, and apigenin addition could enhance the effects of the inhibitor and antagonize the effects of the mimic. Luciferase reporter gene assay demonstrated that c-Ski was a direct target of miR-155-5p.

CONCLUSION

These findings suggested that apigenin could inhibit the differentiation and ECM production in TGF-β1-stimulated CFs, and its mechanisms might partly be attributable to the reduction of miR-155-5p expression and subsequent increment of c-Ski expression, which might result in the inhibition of Smad2/3 and p-Smad2/3 expressions.

Aberrant Methylation of miR-34b and IL-12B mRNA Promoters Contributes to the Reduced Severity of Ankylosing Spondylitis

DNA methylation of Interleukin-12B (IL-12B) and miR-34b was proved to affect the expression of IL-12B and miR-34b, which were found to be involved in the pathogenesis of ankylosing spondylitis (AS). However, the molecular mechanisms underlying the role of IL-12B and miR-34b in AS remain to be explored. AS patients were divided into four groups according to their status of DNA methylation of miR-34b and IL-12B by bisulfite sequencing: HYPER-miR-34b + HYPO-IL-12B, HYPER-miR-34b + HYPER-IL-12B, HYPO-miR-34b + HYPER-IL-12B and HYPO-miR-34b + HYPO-IL-12B groups. Functional indicators were examined for patients with different status of DNA methylation in their miR-34b and IL-12B promoters. QPCR was performed to examine the expression of miR-34b and IL-12B mRNA under different conditions. ELISA was used to measure the expression of IL-12B p40 in the peripheral blood. Western blot was used to analyze the expression of IL-12B proteins. Luciferase assay was carried out to explore the suppressive role of miR-34b in IL-12B expression. The level of Ankylosing Spondylitis Disease Activity Score with C-reactive protein (ASDAS-CRP) was gradually increased in HYPER-miR-34b + HYPO-IL-12B,HYPER-miR-34b + HYPER-IL-12B,HYPO-miR-34b + HYPER-IL-12B and HYPO-miR-34b + HYPO-IL-12B groups, whereas the levels of Bath Ankylosing Spondylitis Functional Index (BASFI) and Bath Ankylosing Spondylitis Metrology Index (BASMI) were significantly elevated in the HYPO-miR-34b + HYPO-IL-12B group and diminished in the HYPER-miR-34b + HYPO-IL-12B group. The expression of miR-34b in the PBMCs and peripheral blood was remarkably higher in the HYPER-miR-34b + HYPO-IL-12B and HYPER-miR-34b + HYPER-IL-12B groups, whereas the expression of IL-12B was gradually decreased in the HYPER-miR-34b + HYPO-IL-12B, HYPER-miR-34b + HYPER-IL-12B, HYPO-miR-34b + HYPER-IL-12B and HYPO-miR-34b + HYPO-IL-12B groups. Luciferase assays with the transfection of miR-34b precursors suggested that miR-34b strongly suppressed the expression of IL-12B in THP-1 cells. In conclusion, our study demonstrated that hypermethylated miR-34b promoter led to evident upregulation of miR-34b, thus inhibiting the expression of IL-12B and alleviated the severity of ankylosing spondylitis by reducing the levels of factors including ASDAS-CRP, BASFI and BASMI.

Functional mechanism and clinical implications of MicroRNA-423 in human cancers

MicroRNAs play a vital role in the regulatory mechanisms of tumorigenesis. Current research indicates that microRNA-423 (miR-423) is abnormally expressed in various human tumors and participates in multiple signaling pathways of cancer progression. In most studies, miR-423 was confirmed as oncomiR, while a few contradictory reports considered miR-423 as an anticancer miRNA. The paradoxical role in cancer may hinder the application of miR-423 as a diagnostic and therapeutic target. Simultaneously, the interaction mechanism between miR-423 and lncRNA also needs attention. In this review, we have summarized the dual role of aberrant miR-423 expression and its mechanisms in tumorigenesis, and the therapeutic potential of miR-423 in human tumors.

Pyrvinium pamoate induces in-vitro suppression of IL-6 and IL-8 produced by human endometriotic stromal cells

Endometriosis, a chronic inflammatory disease, is identified by the presence of endometrial tissue outside the uterus. The prevalence of this disease among reproductive-age women is almost 10-15%. High levels of IL-6 and IL-8 have been found in the peritoneal fluid (PF) of women with endometriosis and are involved in its pathogenesis. Isolated stromal cells from 12 ectopic and eutopic endometrial biopsies of women with ovarian endometrioma and also 12 endometrial biopsies of nonendometriotic controls were treated with 1.1 µM pyrvinium pamoate, a Wnt/β-catenin signaling pathway inhibitor, for 72 hrs. Before treatment, mRNA gene expression and secretion of IL-6 and IL-8 were significantly higher in ectopic (EESCs) than eutopic (EuESCs) and control (CESCs) endometrial stromal cells. After treatment, mRNA gene expression and also secretion of IL-6 and IL-8 were significantly reduced. Our Findings showed that pyrvinium pamoate suppresses the mRNA gene expression and secretion of IL-6 and IL-8 in human endometriotic stromal cells. Additional investigations on this compound are required before clinical application.

Nature-derived compounds modulating Wnt/ -catenin pathway: a preventive and therapeutic opportunity in neoplastic diseases

The Wnt/β-catenin signaling is a conserved pathway that has a crucial role in embryonic and adult life. Dysregulation of the Wnt/β-catenin pathway has been associated with diseases including cancer, and components of the signaling have been proposed as innovative therapeutic targets, mainly for cancer therapy. The attention of the worldwide researchers paid to this issue is increasing, also in view of the therapeutic potential of these agents in diseases, such as Parkinson's disease (PD), for which no cure is existing today. Much evidence indicates that abnormal Wnt/β-catenin signaling is involved in tumor immunology and the targeting of Wnt/β-catenin pathway has been also proposed as an attractive strategy to potentiate cancer immunotherapy. During the last decade, several products, including naturally occurring dietary agents as well as a wide variety of products from plant sources, including curcumin, quercetin, berberin, and ginsenosides, have been identified as potent modulators of the Wnt/β-catenin signaling and have gained interest as promising candidates for the development of chemopreventive or therapeutic drugs for cancer. In this review we make an overview of the nature-derived compounds reported to have antitumor activity by modulating the Wnt/β-catenin signaling, also focusing on extraction methods, chemical features, and bio-activity assays used for the screening of these compounds.

Abatement of the Stimulatory Effect of Copper Nanoparticles Supported on Titania on Ovarian Cell Functions by Some Plants and Phytochemicals

The application of nanoparticles has experienced a vertiginous growth, but their interaction with food and medicinal plants in organisms, especially in the control of reproduction, remains unresolved. We examined the influence of copper nanoparticles supported on titania (CuNPs/TiO2), plant extracts (buckwheat (Fagopyrum esculentum) and vitex (Vitex agnus-castus)), phytochemicals (rutin and apigenin), and their combination with CuNPs/TiO2 on ovarian cell functions, using cultured porcine ovarian granulosa cells. Cell viability, proliferation (PCNA accumulation), apoptosis (accumulation of bax), and hormones release (progesterone, testosterone, and 17β-estradiol) were analyzed by the Trypan blue test, quantitative immunocytochemistry, and ELISA, respectively. CuNPs/TiO2 increased cell viability, proliferation, apoptosis, and testosterone but not progesterone release, and reduced the 17β-estradiol output. Plant extracts and components have similar stimulatory action on ovarian cell functions as CuNPs/TiO2, but abated the majority of the CuNPs/TiO2 effects. This study concludes that (1) CuNPs/TiO2 can directly stimulate ovarian cell functions, promoting ovarian cell proliferation, apoptosis, turnover, viability, and steroid hormones release; (2) the plants buckwheat and vitex, as well as rutin and apigenin, can promote some of these ovarian functions too; and (3) these plant additives mitigate the CuNPs/TiO2's activity, something that must be considered when applied together.

Targeting the JAK/STAT Signaling Pathway Using Phytocompounds for Cancer Prevention and Therapy

Cancer is a prevalent cause of mortality around the world. Aberrated activation of Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling pathway promotes tumorigenesis. Natural agents, including phytochemicals, exhibit potent anticancer activities via various mechanisms. However, the therapeutic potency of phytoconstituents as inhibitors of JAK/STAT signaling against cancer has only come into focus in recent days. The current review highlights phytochemicals that can suppress the JAK/STAT pathway in order to impede cancer cell growth. Various databases, such as PubMed, ScienceDirect, Web of Science, SpringerLink, Scopus, and Google Scholar, were searched using relevant keywords. Once the authors were in agreement regarding the suitability of a study, a full-length form of the relevant article was obtained, and the information was gathered and cited. All the complete articles that were incorporated after the literature collection rejection criteria were applied were perused in-depth and material was extracted based on the importance, relevance, and advancement of the apprehending of the JAK/STAT pathway and their relation to phytochemicals. Based on the critical and comprehensive analysis of literature presented in this review, phytochemicals from diverse plant origins exert therapeutic and cancer preventive effects, at least in part, through regulation of the JAK/STAT pathway. Nevertheless, more preclinical and clinical research is necessary to completely comprehend the capability of modulating JAK/STAT signaling to achieve efficient cancer control and treatment.

Apigenin induces apoptosis and counteracts cisplatin-induced chemoresistance via Mcl-1 in ovarian cancer cells

Ovarian cancer (OC) is one of the prominent causes of mortality in female patients diagnosed with gynecologic malignancies. While it has previously been demonstrated that apigenin inhibits cell growth in colon and breast cancer cells, the effect of apigenin in OC cells is not fully understood. Therefore, the aim of the present study was to investigate the impact of apigenin on cell death and resistance to cisplatin in OC cells. It was found that apigenin inhibited proliferation, hindered cell cycle progression and promoted SKOV3 cell apoptosis. Moreover, these effects were also observed in cisplatin-resistant SKOV3/DDP cells. Furthermore, apigenin reduced the mitochondrial transmembrane potential, and elevated the ratios of cleaved caspase-3/caspase-3 and Bax/Bcl-2 in the two cell types. Reverse transcription-quantitative PCR and western blotting results demonstrated that apigenin significantly downregulated Mcl-1 at the transcriptional and translational levels in SKOV3 and SKOV3/DDP cells, which was responsible for its cytotoxic functions and chemosensitizing effects. Collectively, the present results identified the impact of apigenin on OC cell death and resistance to cisplatin, and the potential molecular mechanisms. However, additional studies are required to further elucidate the underlying mechanisms.

Concise review: Coarse cereals exert multiple beneficial effects on human health

Coarse cereals (CC) refer to cereal grains except for rice and wheat which are highly-valued as functional foods with nutritional and pharmacological properties. Owing to their diverse positive effect on chronic diseases, coarse cereals exert a vital role in food industry. CC and the main contents prevent tumor pathogenesis through promoting apoptosis, inducing cell cycle arrest as well as modulating metastasis initiation. Meanwhile, CC ameliorates cardiovascular diseases through affecting multiple pathways, such as CaMKII/p-BFAF-3, NF-κB, MAPK, PI3K/Akt, etc. Besides, CC and the main contents have potential as prebiotics which facilitating the activities and growth of probiotics such as Bifidobacteria and Lactobacillus. However, there's a lack of report on CC' beneficial properties and the underlying mechanisms are not fully understood. Here this article explains in detail, the effect and mechanism of CC on chronic diseases like tumor, inflammation and cardiovascular diseases.

Whole Transcriptomic Analysis of Apigenin on TNFα Immuno-activated MDA-MB-231 Breast Cancer Cells

BACKGROUND

Triple-negative breast cancer is categorized by a lack of hormone receptors, inefficacy of anti-estrogen or aromatase inhibitor chemotherapies and greater mortality rates in African American populations. Advanced-stage breast tumors have a high concentration of tumor necrosis factor-α (TNFα) throughout the tumor/stroma milieu, prompting sustained release of diverse chemokines (i.e. C-C motif chemokine ligand 2 (CCL2)/CCL5). These potent chemokines can subsequently direct mass infiltration of leukocyte sub-populations to lodge within the tumor, triggering a loss of tumor immune surveillance and subsequent rapid tumor growth. Previously, we demonstrated that in the MDA-MB-231 TNBC cell line, TNFα evoked a rise in immune signaling proteins: CCL2, granulocyte macrophage colony-stimulating factor, interleukin (IL)1α, IL6 and inhibitor of nuclear factor kappa-B kinase subunit epsilon (IKBKε) all of which were attenuated by apigenin, a dietary flavonoid found in chamomile and parsley.

MATERIALS AND METHODS

The present work elucidates changes evoked by TNFα in the presence or absence of apigenin by examining the entire transcriptome for mRNA and long intergenic non-coding RNA with Affymetrix Hugene-2.1_ST human microarrays. Differential gene-expression analysis was conducted on 48,226 genes.

RESULTS

TNFα caused up-regulation of 75 genes and down-regulation of 10. Of these, apigenin effectively down-regulated 35 of the 75 genes which were up-regulated by TNFα. These findings confirm our previous work, specifically for the TNFα-evoked spike in IL1A vs. untreated controls [+21-fold change (FC), p<0.0001] being attenuated by apigenin in the presence of TNFa (-15 FC vs. TNFα, p<0.0001). Similar trends were seen for apigenin-mediated down-regulation of TNFα-up-regulated transcripts: IKBKE (TNFα: 4.55 FC vs. control, p<0.001; and TNFα plus apigenin: -4.92 FC, p<0.001), CCL2 (2.19 FC, p<0.002; and -2.12 FC, p<0.003), IL6 (3.25 FC, p<0.020; and -2.85 FC, p<0.043) and CSF2 (TNFα +6.04 FC, p<0.001; and -2.36 FC, p<0.007). In addition, these data further establish more than a 65% reduction by apigenin for the following transcripts which were also up-regulated by TNFα: cathepsin S (CTSS), complement C3 (C3), laminin subunit gamma 2 (LAMC2), (TLR2), toll-like receptor 2 G protein-coupled receptor class C group 5 member B (GPRC5B), contactin-associated protein 1 (CNTNAP1), claudin 1 (CLDN1), nuclear factor of activated T-cells 2 (NFATC2), C-X-C motif chemokine ligand 10 (CXCL10), CXCL11, interleukin 1 receptor-associated kinase 3 (IRAK3), nuclear receptor subfamily 3 group C member 2 (NR3C2), interleukin 32 (IL32), IL24, slit guidance ligand 2 (SLIT2), transmembrane protein 132A (TMEM132A), TMEM171, signal transducing adaptor family member 2 (STAP2), mixed lineage kinase domain-like pseudokinase (MLKL), kinase insert domain receptor (KDR), BMP-binding endothelial regulator (BMPER), and kelch-like family member 36 (KLHL36).

CONCLUSION

There is a possible therapeutic role for apigenin in down-regulating diverse genes associated with tumorigenic leukocyte sub-population infiltration by triple-negative breast cancer. The data have been deposited into the Gene Expression Omnibus for public analysis at https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE120550.

Small Molecule Wnt Pathway Modulators from Natural Sources: History, State of the Art and Perspectives

The Wnt signaling is one of the major pathways known to regulate embryonic development, tissue renewal and regeneration in multicellular organisms. Dysregulations of the pathway are a common cause of several types of cancer and other diseases, such as osteoporosis and rheumatoid arthritis. This makes Wnt signaling an important therapeutic target. Small molecule activators and inhibitors of signaling pathways are important biomedical tools which allow one to harness signaling processes in the organism for therapeutic purposes in affordable and specific ways. Natural products are a well known source of biologically active small molecules with therapeutic potential. In this article, we provide an up-to-date overview of existing small molecule modulators of the Wnt pathway derived from natural products. In the first part of the review, we focus on Wnt pathway activators, which can be used for regenerative therapy in various tissues such as skin, bone, cartilage and the nervous system. The second part describes inhibitors of the pathway, which are desired agents for targeted therapies against different cancers. In each part, we pay specific attention to the mechanisms of action of the natural products, to the models on which they were investigated, and to the potential of different taxa to yield bioactive molecules capable of regulating the Wnt signaling.

Coptisine from Coptis chinensis exerts diverse beneficial properties: A concise review

Coptisine is a natural small-molecular compound extracted from Coptis chinensis (CC) with a history of using for thousands of years. This work aimed at summarizing coptisine's activity and providing advice for its clinical use. We analysed the online papers in the database of SciFinder, Web of Science, PubMed, Google scholar and CNKI by setting keywords as 'coptisine' in combination of 'each pivotal pathway target'. Based on the existing literatures, we find (a) coptisine exerted potential to be an anti-cancer, anti-inflammatory, CAD ameliorating or anti-bacterial drug through regulating the signalling transduction of pathways such as NF-κB, MAPK, PI3K/Akt, NLRP3 inflammasome, RANKL/RANK and Beclin 1/Sirt1. However, we also (b) observe that the plasma concentration of coptisine demonstrates obvious non-liner relationship with dosage, and even the highest dosage used in animal study actually cannot reach the minimum concentration level used in cell experiments owing to the poor absorption and low availability of coptisine. We conclude (a) further investigations can focus on coptisine's effect on caspase-1-involved inflammasome assembling and pyroptosis activation, as well as autophagy. (b) Under circumstance of promoting coptisine availability by pursuing nano- or microrods strategies or applying salt-forming process to coptisine, can it be introduced to clinical trial.

MiR-34b regulates cervical cancer cell proliferation and apoptosis

Objectives: MiR-34b is a tumour suppressor in different kinds of carcinomas. This study investigated the role of miR-34b in proliferation and apoptosis of cervical cancer. Materials and methods: The expression of miR-34b in 60 cervical cancer patients were quantified by RT-PCR and correlated with their clinicopathological parameters. Besides, there is a significant reverse relationship between miR-43b and TGF-β1 expression in tumour tissues. Cell proliferation and apoptosis was detected by CCK-8 assays and flow cytometry in cell lines transfected with miR-34b mimics. Western blotting, quantitative reverse transcription-PCR (RT-PCR) and luciferase assays were conducted to analyze the regulation of TGF-β1 by miR-34b in cell lines. Results: Here, we found expression of miR-34b to be downregulated in cervical cancer in comparison with the adjacent normal tissues. Expression levels of miR-34b were associated with enhanced malignant potential, such as tumour stage and stromal invasion. The overexpression of miR-34b potently suppressed cell proliferation and induced the apoptosis of cell lines. Conclusions: MiR-34b and TGF-β1 contribute to cervical cancer cell proliferation and apoptosis and are potential targets for cervical cancer therapeutics.

Apigenin Inhibits IL-6 Transcription and Suppresses Esophageal Carcinogenesis

Esophagus cancer is the seventh cause of cancer-related deaths globally. In this study, we analyzed interleukin 6 (IL-6) gene expression in human esophagus cancer patients and showed that IL-6 mRNA levels are significantly higher in tumor tissues and negatively correlated with overall survival, suggesting that IL-6 is a potential therapeutic target for esophagus cancer. We further demonstrated that apigenin, a nature flavone product of green plants, inhibited IL-6 transcription and gene expression in human esophagus cancer Eca-109 and Kyse-30 cells. Apigenin significantly and dose-dependently inhibited cell proliferation and promoted apoptosis while stimulating the cleaved PARP (poly ADP-ribose polymerase) (C-PARP) and caspase-8 expression. It suppressed VEGF (Vascular endothelial growth Factor) expression and tumor-induced angiogenesis. Pretreatment of cells with IL-6 could completely reverse apigenin-induced cellular changes. Finally, using a preclinical nude mice model subcutaneously xenografted with Eca-109 cells, we demonstrated the in vivo antitumor activity and mechanisms of apigenin. Taken together, this study revealed for the first time that apigenin is a new IL-6 transcription inhibitor and that inhibiting IL-6 transcription is one of the mechanisms by which apigenin exhibits its anticancer effects. The potential clinical applications of apigenin in treating esophagus cancer warrant further investigations.

Apigenin inhibits fibroblast proliferation and reduces epidural fibrosis by regulating Wnt3a/β-catenin signaling pathway

BACKGROUND

Failed back surgery syndrome (FBSS) is a common complication after the laminectomy. Epidural fibrosis is the major cause of lower back pain and other complications. Numerous studies have shown that apigenin (API) could treat various fibrotic diseases by regulating various signaling pathways, whereas no study has discussed whether API can inhibit fibroblast proliferation and reduce epidural fibrosis after the laminectomy by regulating Wnt3a/β-catenin signaling pathway.

METHODS

Human fibroblasts were cultured and treated with API in different concentrations for 24 h. CCK-8 detection and EdU incorporation assay were performed to detect cell viability and cell proliferation. Western blotting analysis was applied to detect expressions of proliferative proteins, Wnt3a, and its downstream proteins. Moreover, the Wnt3a gene was overexpressed in fibroblasts to define the relationship between Wnt3a/β-catenin signaling pathway and fibroblast proliferation. Wnt3a overexpressed fibroblasts were treated with API to verify if it could reverse the effects of API treatment. Twenty-four Sprague-Dawley rats were randomly divided into four groups. Laminectomy was performed and the rats were gavaged with different doses of API or 5% sodium carboxyl methyl cellulose (CMC-Na) solution for 1 month. The abilities of API to inhibit fibroblast proliferation and to reduce epidural fibrosis were evaluated using histological and immunohistochemical analysis.

RESULTS

CCK-8 detection and EdU incorporation assay demonstrated that API could inhibit the viability and proliferation rate of fibroblasts in a concentration-dependent manner. The Western blotting analysis revealed that API could inhibit the expressions of PCNA, cyclinD1, Wnt3a, and its downstream proteins. The overexpression of Wnt3a in fibroblasts could upregulate the expressions of proliferative proteins such as PCNA and cyclinD1. The inhibitory effect of API on PCNA, Wnt3a, and its downstream proteins was partially reversed by overexpression of Wnt3a. Moreover, the results of the histological and immunohistochemical analysis revealed that API could reduce the epidural fibrosis in rats by inhibiting fibroblast proliferation in a dose-dependent manner.

CONCLUSIONS

API can inhibit fibroblast proliferation and reduce epidural fibrosis by suppressing Wnt3a/β-catenin signaling pathway, which can be adopted as a new option to prevent epidural fibrosis after the laminectomy.

Wnt Signaling: A Potential Therapeutic Target in Head and Neck Squamous Cell Carcinoma

Cellular maintenance and development are two fundamental mechanisms regulated by the canonical Wnt signaling pathway. Wnt/beta-catenin signaling pathway controls a myriad of cellular processes that are essential for normal cell functioning. Cell cycle progression, differentiation, fate determination, and migration are generally orchestrated by canonical Wnt signaling. Altered Wnt/beta-catenin signaling has been considered a promoting event for different types of cancers and the oncogenic potential of Wnt signaling have been discussed in many cancer types, including breast, colon, pancreatic as well as head and neck. Furthermore, Wnt signaling is critical for the maintenance and stemness of both the normal as well as cancer stem cells. This review sheds new light on Wnt signaling and explains how it can regulate normal physiological processes and curtail the development of cancer. It depicts the vital functions of Wnt signaling in the stem cell growth and differentiation by focusing on current druggable targets that have been ascribed by recent studies. Thus, Wnt signaling pathway retains a tremendous potential in eradicating head and neck squamous cell carcinoma.

Dissolution and bioavailability improvement of bioactive apigenin using solid dispersions prepared by different techniques

Apigenin (APG) is a poorly soluble bioactive compound/nutraceutical which shows poor bioavailability upon oral administration. Hence, the objective of this research work was to develop APG solid dispersions (SDs) using different techniques with the expectation to obtain improvement in its in vitro dissolution rate and in vivo bioavailability upon oral administration. Different SDs of APG were prepared by microwave, melted and kneaded technology using pluronic-F127 (PL) as a carrier. Prepared SDs were characterized using "thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infra-red (FTIR) spectrometer, powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM)". After characterization, prepared SDs of APG were studied for in vitro drug release/dissolution profile and in vivo pharmacokinetic studies. The results of TGA, DSC, FTIR, PXRD and SEM indicated successful formation of APG SDs. In vitro dissolution experiments suggested significant release of APG from all SDs (67.39-84.13%) in comparison with control (32.74%). Optimized SD of APG from each technology was subjected to in vivo pharmacokinetic study in rats. The results indicated significant improvement in oral absorption of APG from SD prepared using microwave and melted technology in comparison with pure drug and commercial capsule. The enhancement in oral bioavailability of APG from microwave SD (319.19%) was 3.19 fold as compared with marketed capsule (100.00%). Significant enhancement in the dissolution rate and oral absorption of APG from SD suggested that developed SD systems can be successfully used for oral drug delivery system of APG.

Targeting Cancer with Phytochemicals via Their Fine Tuning of the Cell Survival Signaling Pathways

The role of phytochemicals as potential prodrugs or therapeutic substances against tumors has come in the spotlight in the very recent years, thanks to the huge mass of encouraging and promising results of the in vitro activity of many phenolic compounds from plant raw extracts against many cancer cell lines. Little but important evidence can be retrieved from the clinical and nutritional scientific literature, where flavonoids are investigated as major pro-apoptotic and anti-metastatic compounds. However, the actual role of these compounds in cancer is still far to be fully elucidated. Many of these phytochemicals act in a pleiotropic and poorly specific manner, but, more importantly, they are able to tune the reactive oxygen species (ROS) signaling to activate a survival or a pro-autophagic and pro-apoptosis mechanism, depending on the oxidative stress-responsive endowment of the targeted cell. This review will try to focus on this issue.