Apigenin Attenuates Melanoma Cell Migration by Inducing Anoikis through Integrin and Focal Adhesion Kinase Inhibition

A literature review on signaling pathways of cervical cancer cell death-apoptosis induced by Traditional Chinese Medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Cervical cancer (CC) is a potentially lethal disorder that can have serious consequences for a woman's health. Because early symptoms are typically only present in the middle to late stages of the disease, clinical diagnosis and treatment can be challenging. Traditional Chinese medicine (TCM) has been shown to have unique benefits in terms of alleviating cancer clinical symptoms, lowering the risk of recurrence after surgery, and reducing toxic side effects and medication resistance after radiation therapy. It has also been shown to improve the quality of life for patients. Because of its improved anti-tumor effectiveness and biosafety, it could be considered an alternative therapy option. This study examines how TCM causes apoptosis in CC cells via signal transduction, including the active components and medicinal tonics. It also intends to provide a reliable clinical basis and protocol selection for the TCM therapy of CC.

METHODS

The following search terms were employed in PubMed, Web of Science, Embase, CNKI, Wanfang, VIP, SinoMed, and other scientific databases to retrieve pertinent literature on "cervical cancer," "apoptosis," "signaling pathway," "traditional Chinese medicine," "herbal monomers," "herbal components," "herbal extracts," and "herbal formulas."

RESULTS

It has been demonstrated that herbal medicines can induce apoptosis in cells of the cervix, a type of cancer, by influencing the signaling pathways involved.

CONCLUSION

A comprehensive literature search was conducted, and 148 papers from the period between January 2017 and December 2023 were identified as eligible for inclusion. After a meticulous process of screening, elimination and summary, generalization, and analysis, it was found that TCM can regulate multiple intracellular signaling pathways and related molecular targets, such as STAT3, PI3K/AKT, Wnt/β-catenin, MAPK, NF-κB, p53, HIF-1α, Fas/FasL and so forth. This regulatory capacity was observed to induce apoptosis in cervical cancer cells. The study of the mechanism of TCM against cervical cancer and the screening of new drug targets is of great significance for future research in this field. The results of this study will provide ideas and references for the future development of Chinese medicine in the diagnosis and treatment of cervical cancer.

Apigenin: Molecular Mechanisms and Therapeutic Potential against Cancer Spreading

Due to its propensity to metastasize, cancer remains one of the leading causes of death worldwide. Thanks in part to their intrinsic low cytotoxicity, the effects of the flavonoid family in the prevention and treatment of various human cancers, both in vitro and in vivo, have received increasing attention in recent years. It is well documented that Apigenin (4',5,7-trihydroxyflavone), among other flavonoids, is able to modulate key signaling molecules involved in the initiation of cancer cell proliferation, invasion, and metastasis, including JAK/STAT, PI3K/Akt/mTOR, MAPK/ERK, NF-κB, and Wnt/β-catenin pathways, as well as the oncogenic non-coding RNA network. Based on these premises, the aim of this review is to emphasize some of the key events through which Apigenin suppresses cancer proliferation, focusing specifically on its ability to target key molecular pathways involved in angiogenesis, epithelial-to-mesenchymal transition (EMT), maintenance of cancer stem cells (CSCs), cell cycle arrest, and cancer cell death.

The Promising Role of Polyphenols in Skin Disorders

The biochemical characteristics of polyphenols contribute to their numerous advantageous impacts on human health. The existing research suggests that plant phenolics, whether consumed orally or applied directly to the skin, can be beneficial in alleviating symptoms and avoiding the development of many skin disorders. Phenolic compounds, which are both harmless and naturally present, exhibit significant potential in terms of counteracting the effects of skin damage, aging, diseases, wounds, and burns. Moreover, polyphenols play a preventive role and possess the ability to delay the progression of several skin disorders, ranging from small and discomforting to severe and potentially life-threatening ones. This article provides a concise overview of recent research on the potential therapeutic application of polyphenols for skin conditions. It specifically highlights studies that have investigated clinical trials and the use of polyphenol-based nanoformulations for the treatment of different skin ailments.

Recent Updates Regarding the Antiproliferative Activity of Galium verum Extracts on A375 Human Malignant Melanoma Cell Line

The biological activity of Galium verum herba was exerted on various tumor cell lines with incredible results, but their potential effect on malignant melanoma has not been established yet. Therefore, the current study was structured in two directions: (i) the investigation of the phytochemical profile of diethyl ether (GvDEE) and butanol (GvBuOH) extracts of G. verum L. and (ii) the evaluation of their biological profile on A375 human malignant melanoma cell line. The GvDEE extract showed an FT-IR profile different from the butanol one, with high antioxidant capacity (EC50 of GvDEE = 0.12 ± 0.03 mg/mL > EC50 of GvBuOH = 0.18 ± 0.05 mg/mL). The GvDEE extract also showed antimicrobial potential, especially against Gram-positive bacteria strains, compared to the butanol extract, which has no antimicrobial activity against any bacterial strain tested. The results regarding the antitumor potential showed that both extracts decreased A375 cell viability largely (69% at a dose of 55 µg/mL of the GvDEE extract). Moreover, both extracts induce nuclear fragmentation by forming apoptotic bodies and slight chromatin condensation, which is more intense for GvDEE. Considering the results, one can state that the Galium verum herba possesses antitumor effects on the A375 human malignant melanoma cell line, a promising phytocompound for the antitumor approach to skin cancer.

Bitter Phytochemicals as Novel Candidates for Skin Disease Treatment

Skin diseases represent a global healthcare challenge due to their rising incidence and substantial socio-economic burden. While biological, immunological, and targeted therapies have brought a revolution in improving quality of life and survival rates for certain dermatological conditions, there remains a stringent demand for new remedies. Nature has long served as an inspiration for drug development. Recent studies have identified bitter taste receptors (TAS2Rs) in both skin cell lines and human skin. Additionally, bitter natural compounds have shown promising benefits in addressing skin aging, wound healing, inflammatory skin conditions, and even skin cancer. Thus, TAS2Rs may represent a promising target in all these processes. In this review, we summarize evidence supporting the presence of TAS2Rs in the skin and emphasize their potential as drug targets for addressing skin aging, wound healing, inflammatory skin conditions, and skin carcinogenesis. To our knowledge, this is a pioneering work in connecting information on TAS2Rs expression in skin and skin cells with the impact of bitter phytochemicals on various beneficial effects related to skin disorders.

An anoikis-related lncRNA signature is a useful tool for predicting the prognosis of patients with lung adenocarcinoma

Background

Anoikis-related long non-coding RNAs (ARLs) play a critical role in tumor metastasis and progression, suggesting that they may serve as risk markers for cancer. This study aimed to investigate the prognostic value of ARLs in patients with lung adenocarcinoma (LUAD).

Methods

Clinical data, RNA sequencing (RNA-seq) data, and mutation data from the LUAD project were obtained from The Cancer Genome Atlas (TCGA) database. The Molecular Signatures Database (MSigDB) and the GeneCard database were used to collect an anoikis-related gene (ARG) set. Pearson correlation analysis was performed to identify ARLs. LASSO and Cox regression were then used to establish a prognostic risk signature for ARLs. The median risk score served as the basis for categorizing patients into high and low-risk groups. Kaplan-Meier analysis was utilized to compare the prognosis between these two groups. The study also examined the associations between risk scores and prognosis, clinicopathological characteristics, immune status, tumor mutation burden (TMB), and chemotherapeutic agents. LncRNA expression was assessed using quantitative real-time PCR (qRT-PCR).

Results

A total of 480 RNA expression profiles, 501 ARGs, and 2698 ARLs were obtained from the database. A prognostic ARL signature for LUAD was established, consisting of 9 lncRNAs. Patients in the low-risk group exhibited significantly better prognosis compared to those in the high-risk group (P < 0.001). The 9 lncRNAs from the ARL signature were identified as independent prognostic factors (P < 0.001). The signature demonstrated high accuracy in predicting LUAD prognosis, with area under the curve values exceeding 0.7. The risk scores for ARLs showed strong negative correlations with stroma score (P = 5.9E-07, R = -0.23), immune score (P = 9.7E-09, R = -0.26), and microenvironment score (P = 8E-11, R = -0.29). Additionally, the low-risk group exhibited significantly higher TMB compared to the high-risk group (P = 4.6E-05). High-risk status was significantly associated with lower half-maximal inhibitory concentrations for most chemotherapeutic drugs.

Conclusion

This newly constructed signature based on nine ARLs is a useful instrument for the risk stratification of LUAD patients. The signature has potential clinical significance for predicting the prognosis of LUAD patients and guiding personalized immunotherapy.

Therapeutic targeting of anoikis resistance in cutaneous melanoma metastasis

The acquisition of resistance to anoikis, the cell death induced by loss of adhesion to the extracellular matrix, is an absolute requirement for the survival of disseminating and circulating tumour cells (CTCs), and for the seeding of metastatic lesions. In melanoma, a range of intracellular signalling cascades have been identified as potential drivers of anoikis resistance, however a full understanding of the process is yet to be attained. Mechanisms of anoikis resistance pose an attractive target for the therapeutic treatment of disseminating and circulating melanoma cells. This review explores the range of small molecule, peptide and antibody inhibitors targeting molecules involved in anoikis resistance in melanoma, and may be repurposed to prevent metastatic melanoma prior to its initiation, potentially improving the prognosis for patients.

Melanoma Cellular Signaling Transduction Pathways Targeted by Polyphenols Action Mechanisms

Melanoma is the most aggressive type of skin cancer. Although different anti-melanoma treatments are available, their efficacy is still improvable, and the number of deaths continues to increase worldwide. A promising source of antitumor agents could be presented by polyphenols-natural plant-based compounds. Over the past decades, many studies have described multiple anticancer effects of polyphenols in melanoma, presenting their potential interactions with targeted molecules from different signaling pathways. However, to our knowledge, there is no comprehensive review on polyphenols-regulated mechanisms in melanoma cells available in the literature. To fulfill this gap, this article aims to summarize the current knowledge of molecular mechanisms of action regulated by polyphenols involved in melanoma initiation and progression. Here, we focus on in vitro and in vivo effects of polyphenol treatments on tumor-essential cellular pathways, such as cell proliferation, apoptosis, autophagy, inflammation, angiogenesis, and metastasis. Moreover, emerging studies regarding the well-marked role of polyphenols in the regulation of microRNAs (miRNAs), highlighting their contribution to melanoma development, are also epitomized. Finally, we hope this review will provide a firm basis for developing polyphenol-based therapeutic agents in melanoma treatment.

Apigenin in cancer therapy: Prevention of genomic instability and anticancer mechanisms

The incidence of cancer has been growing worldwide. Better survival rates following the administration of novel drugs and new combination therapies may concomitantly cause concern regarding the long-term adverse effects of cancer therapy, for example, second primary malignancies. Moreover, overcoming tumour resistance to anticancer agents has been long considered as a critical challenge in cancer research. Some low toxic adjuvants such as herb-derived molecules may be of interest for chemoprevention and overcoming the resistance of malignancies to cancer therapy. Apigenin is a plant-derived molecule with attractive properties for chemoprevention, for instance, promising anti-tumour effects, which may make it a desirable adjuvant to reduce genomic instability and the risks of second malignancies among normal tissues. Moreover, it may improve the efficiency of anticancer modalities. This paper aims to review various effects of apigenin in both normal tissues and malignancies. In addition, we explain how apigenin may have the ability to protect usual cells against the genotoxic repercussions following radiotherapy and chemotherapy. Furthermore, the inhibitory effects of apigenin on tumours will be discussed.

Apigenin and its dermatological applications: A comprehensive review

Apigenin is one of the abundant flavonoids in fruits and vegetables of human diet with several demonstrated health benefits. The aim of the present study is to provide an overview of the current evidence regarding the effect of apigenin on different dermatological complications. Electronic databases including PubMed, Scopus, and Web of Science were searched to retrieve all papers assessing the dermatological effects of apigenin. Preclinical studies support beneficial effects of apigenin on UV-induced skin damage, vitiligo, dermatitis, wounds, skin aging, and some types of skin cancer. The compound mostly acts via inhibition of inflammation through suppression of pro-inflammatory cytokines and intracellular inflammatory mediators, as well as antioxidant properties such as improvement of endogenous antioxidant defense mechanisms. There are also some studies for the design and development of novel drug delivery systems for apigenin to improve its oral and topical bioavailability. Nevertheless, no clinical study has evaluated apigenin as a natural supplement for skin conditions. Considering the benefits of apigenin in preclinical models of dermatological disorders, as well as the acceptable safety of this compound, apigenin may be a future candidate to be used in dermatological disorders. Future clinical studies are needed to further confirm the safety and efficacy of apigenin in skin care products.

Apigenin Induced Apoptosis by Downregulating Sulfiredoxin Expression in Cutaneous Squamous Cell Carcinoma

Cutaneous squamous cell carcinoma (cSCC) is the second carcinoma in nonmelanoma skin cancer (NMSC). Sulfiredoxin (Srx) is an antioxidant protein with a role in maintaining redox homeostasis. And Srx has an oncogenic role in skin tumorigenesis. In the current study, we found that apigenin, as a natural flavonoid, downregulated the expression of Srx protein in cSCC cell lines. Apigenin also inhibited the ability of cell proliferation and migration and induced apoptosis in cSCC cell lines. Our results also showed that apigenin induced apoptosis via the activation of the mitogen-activated protein kinase (MAPK) signaling pathway, as well as downregulated Srx expression in cSCC cell lines. Importantly, the effect of downregulation Srx by apigenin has been rescued with the inhibitor of the MAPK signaling pathway intervention. And induced apoptosis by apigenin was partially attenuated by the addition of MAPK inhibitor, Binimetinib. Our research revealed that apigenin induced apoptosis by downregulation of Srx expression through regulating the MAPK signaling pathway in cSCC cells, thus providing evidence of its applicability as a potentially effective therapeutic agent for cSCC treatment.

Pharmacological Properties of 4′, 5, 7-Trihydroxyflavone (Apigenin) and Its Impact on Cell Signaling Pathways

Plant bioactive compounds, particularly apigenin, have therapeutic potential and functional activities that aid in the prevention of infectious diseases in many mammalian bodies and promote tumor growth inhibition. Apigenin is a flavonoid with low toxicities and numerous bioactive properties due to which it has been considered as a traditional medicine for decades. Apigenin shows synergistic effects in combined treatment with sorafenib in the HepG2 human cell line (HCC) in less time and statistically reduces the viability of tumor cells, migration, gene expression and apoptosis. The combination of anti-cancerous drugs with apigenin has shown health promoting potential against various cancers. It can prevent cell mobility, maintain the cell cycle and stimulate the immune system. Apigenin also suppresses mTOR activity and raises the UVB-induced phagocytosis and reduces the cancerous cell proliferation and growth. It also has a high safety threshold, and active (anti-cancer) doses can be gained by consuming a vegetable and apigenin rich diet. Apigenin also boosted autophagosome formation, decreased cell proliferation and activated autophagy by preventing the activity of the PI3K pathway, specifically in HepG2 cells. This paper provides an updated overview of apigenin’s beneficial anti-inflammatory, antibacterial, antiviral, and anticancer effects, making it a step in the right direction for therapeutics. This study also critically analyzed the effect of apigenin on cancer cell signaling pathways including the PI3K/AKT/MTOR, JAK/STAT, NF-κB and ERK/MAPK pathways.

Selected Flavonoids to Target Melanoma: A Perspective in Nanoengineering Delivery Systems

Melanoma is a complex type of cancer that depends on several metabolic factors, while the currently used therapies are not always effective and have unwanted side effects. In this review, the main factors involved in the etiology of cutaneous carcinoma are highlighted, together with the main genes and proteins that regulate cancer invasion and metastization. The role of five selected flavonoids, namely, apigenin, epigallocatechin-3-gallate, kaempferol, naringenin, and silybin, in the modulating receptor tyrosine kinase (RTK) and Wnt pathways is reported with their relevance in the future design of drugs to mitigate and/or treat melanoma. However, as phenolic compounds have some difficulties in reaching the target site, the encapsulation of these compounds in nanoparticles is a promising strategy to promote improved physicochemical stabilization of the bioactives and achieve greater bioavailability. Scientific evidence is given about the beneficial effects of loading these flavonoids into selected nanoparticles for further exploitation in the treatment of melanoma.

Targeting cancer signaling pathways by natural products: Exploring promising anti-cancer agents

Cancer is one of the leading causes of death and significantly burdens the healthcare system. Due to its prevalence, there is undoubtedly an unmet need to discover novel anticancer drugs. The use of natural products as anticancer agents is an acceptable therapeutic approach due to accessibility, applicability, and reduced cytotoxicity. Natural products have been an incomparable source of anticancer drugs in the modern era of drug discovery. Along with their derivatives and analogs, natural products play a major role in cancer treatment by modulating the cancer microenvironment and different signaling pathways. These compounds are effective against several signaling pathways, mainly cell death pathways (apoptosis and autophagy) and embryonic developmental pathways (Notch pathway, Wnt pathway, and Hedgehog pathway). The historical record of natural products is strong, but there is a need to investigate the current role of natural products in the discovery and development of cancer drugs and determine the possibility of natural products being an important source of future therapeutic agents. Many target-specific anticancer drugs failed to provide successful results, which accounts for a need to investigate natural products with multi-target characteristics to achieve better outcomes. The potential of natural products to be promising novel compounds for cancer treatment makes them an important area of research. This review explores the significance of natural products in inhibiting the various signaling pathways that serve as drivers of carcinogenesis and thus pave the way for developing and discovering anticancer drugs.

The Effect of Encapsulated Apigenin Nanoparticles on HePG-2 Cells through Regulation of P53

Apigenin (Ap) is one of the most important natural flavonoids that has potent anticancer activity. This study was designed, for the first time, to load Ap into chitosan to improve its hydrophobicity and then it was coated with albumin-folic acid to increase its stability and bioavailability and to target cancer cells. The newly developed encapsulated Ap (Ap-CH-BSA-FANPs) was characterized and tested in vitro. The zeta potential of −17.0 mV was within the recommended range (−30 mV to +30 mV), indicating that encapsulated apigenin would not quickly settle and would be suspended. The in vitro results proved the great anticancer activity of the encapsulated apigenin on HePG-2 cells compared to pure Ap. The treated HePG-2 cells with Ap-CH-BSA-FANPs demonstrated the induction of apoptosis by increasing p53 gene expression, arresting the cell cycle, increasing caspase-9 levels, and decreasing both the MMP9 gene and Bcl-2 protein expression levels. Moreover, the higher antioxidant activity of the encapsulated apigenin treatment was evident through increasing SOD levels and decreasing the CAT concentration. In conclusion, the Ap-CH-BSA-FANPs were easy to produce with low coast, continued drug release, good loading capacity, high solubility in physiological pH, and were more stable than the formerly Ap-loaded liposomes or PLGA. Moreover, Ap-CH-BSA-FANPs may be a promising chemotherapeutic agent in the treatment of HCC.

Anticancer Effects and Molecular Mechanisms of Apigenin in Cervical Cancer Cells

Cervical cancer is the fourth most frequent malignancy in women. Apigenin is a natural plant-derived flavonoid present in common fruit, vegetables, and herbs, and has been found to possess antioxidant and anti-inflammatory properties as a health-promoting agent. It also exhibits important anticancer effects in various cancers, but its effects are not widely accepted by clinical practitioners. The present study investigated the anticancer effects and molecular mechanisms of apigenin in cervical cancer in vitro and in vivo. HeLa and C33A cells were treated with different concentrations of apigenin. The effects of apigenin on cell viability, cell cycle distribution, migration potential, phosphorylation of PI3K/AKT, the integrin β1-FAK signaling pathway, and epithelial-to-mesenchymal transition (EMT)-related protein levels were investigated. Mechanisms identified from the in vitro study were further validated in a cervical tumor xenograft mouse model. Apigenin effectively inhibited the growth of cervical cancer cells and cervical tumors in xenograft mice. Furthermore, the apigenin down-regulated FAK signaling (FAK, paxillin, and integrin β1) and PI3K/AKT signaling (PI3K, AKT, and mTOR), inactivated or activated various signaling targets, such as Bcl-2, Bax, p21^cip1, CDK1, CDC25c, cyclin B1, fibronectin, N-cadherin, vimentin, laminin, and E-cadherin, promoted mitochondrial-mediated apoptosis, induced G2/M-phase cell cycle arrest, and reduced EMT to inhibit HeLa and C33A cancer cell migration, producing anticancer effects in cervical cancer. Thus, apigenin may act as a chemotherapeutic agent for cervical cancer treatment.

Suppressive Effect and Molecular Mechanism of Houttuynia cordata Thunb. Extract against Prostate Carcinogenesis and Castration-Resistant Prostate Cancer

Simple Summary

This study explored the chemopreventive effects of Houttuynia cordata Thunb. (HCT) extracts against prostate carcinogenesis in both androgen-sensitive prostate cancer and castration-resistant prostate cancer (CRPC) using the Transgenic Rat for Adenocarcinoma of Prostate (TRAP) model, CRPC xenograft mice, and prostate cancer cell lines. HCT suppressed cell proliferation and stimulated apoptosis via inactivation of AKT/ERK/MAPK in both androgen-sensitive prostate cancer and CRPC cell lines. HCT also inhibited cell migration and EMT phenotypes through the STAT3/Snail/Twist pathway. One of the active compounds of HCT was identified as rutin. Consistent with in vitro study, the incidence of adenocarcinoma in the TRAP model and CRPC tumor growth in the xenograft model were suppressed by induction of apoptosis and inactivation of AKT/ERK/MAPK by HCT intake. Our data demonstrated that HCT attenuated androgen-sensitive prostate cancer and CRPC by mechanisms that may involve inhibition of cell growth and caspase-dependent apoptosis pathways.

Abstract

Houttuynia cordata Thunb. (HCT) is a well-known Asian medicinal plant with biological activities used in the treatment of many diseases including cancer. This study investigated the effects of HCT extract and its ethyl acetate fraction (EA) on prostate carcinogenesis and castration-resistant prostate cancer (CRPC). HCT and EA induced apoptosis in androgen-sensitive prostate cancer cells (LNCaP) and CRPC cells (PCai1) through activation of caspases, down-regulation of androgen receptor, and inactivation of AKT/ERK/MAPK signaling. Rutin was found to be a major component in HCT (44.00 ± 5.61 mg/g) and EA (81.34 ± 5.21 mg/g) in a previous study. Rutin had similar effects to HCT/EA on LNCaP cells and was considered to be one of the active compounds. Moreover, HCT/EA inhibited cell migration and epithelial-mesenchymal transition phenotypes via STAT3/Snail/Twist pathways in LNCaP cells. The consumption of 1% HCT-mixed diet significantly decreased the incidence of adenocarcinoma in the lateral prostate lobe of the Transgenic rat for adenocarcinoma of prostate model. Similarly, tumor growth of PCai1 xenografts was significantly suppressed by 1% HCT treatment. HCT also induced caspase-dependent apoptosis via AKT inactivation in both in vivo models. Together, the results of in vitro and in vivo studies indicate that HCT has inhibitory effects against prostate carcinogenesis and CRPC. This plant therefore should receive more attention as a source for the future development of non-toxic chemopreventive agents against various cancers.

An In Vitro-In Vivo Evaluation of the Antiproliferative and Antiangiogenic Effect of Flavone Apigenin against SK-MEL-24 Human Melanoma Cell Line

One of the most important class of natural compounds with successful preclinical results in the management of cancer is the flavonoids. Due to the plethora of biological activities, apigenin (4',5,7 trihydroxyflavone) is a main representant of the flavone subclass. Although the antiproliferative and antiangiogenic effects of apigenin were studied on a significant number of human and murine melanoma cell lines, in order to complete the data existing in the literature, the aim of this study is to evaluate the in vitro effect of apigenin on SK-MEL-24 human melanoma cell line as well as in vivo on tumor angiogenesis using the aforementioned cell line on the chorioallantoic membrane assay. Results have shown that in the range of tested doses, the phytocompound presents significant antiproliferative, cytotoxic, and antimigratory potential at 30 μM, respectively, 60 μM. Moreover, the phytocompound in both tested concentrations limited melanoma cell growth and migration and induced a reduced angiogenic reaction limiting melanoma cell development.

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.

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.

Chrysin Inhibits Melanoma Tumor Metastasis via Interfering with the FOXM1/β-Catenin Signaling

Melanoma, which features high metastasis and high lethality, is one of the toughest tumors to treat. Chrysin, which is rich in various plants, has shown a great inhibitory effect on melanoma proliferation. Here, we evaluated the metastasis suppressive effect of chrysin on melanoma in vivo and in vitro. In vitro, chrysin effectively inhibited ankios resistance from 5 μM cell migration, invasion from 10 μM, and tube formation capacity of melanoma cells from 20 μM. We discovered that chrysin interfered with the mesenchymal-epithelial transition via regulating FOXM1/β-catenin signaling, as the expression of key regulatory factors was downregulated by chrysin treatment, and overexpression of FOXM1 will attenuate the antimetastasis effect of chrysin. We also tested chrysin on lung colonization in melanoma metastasis, where we found fewer tumors were formed in the lungs of chrysin-treated mice. In addition, the expression of FOXM1 was also downregulated by chrysin in vivo. Collectively, our findings suggested the ability of chrysin treatment to lower the metastatic rate of melanoma through regulating FOXM1/β-catenin signaling, indicating the application potential of chrysin for melanoma therapy.

Apigenin inhibits growth and migration of fibroblasts by suppressing FAK signaling

The naturally occurring compound apigenin has many biological effects, including anti-inflammatory, antioxidative and anticancer effects. Although hypertrophic scar formation is a common surgical complication, there is still no good treatment for it. In the present study, we examined the effect of apigenin on hypertrophic scar. After isolating fibroblasts from human hypertrophic scars, we assess the effects of apigenin on fibroblast cell survival, apoptosis and migration. The results showed that apigenin dose-dependently inhibited the growth and migration of hypertrophic scar fibroblasts. By inhibiting FAK kinase activity and FAK phosphorylation, apigenin also inhibited activation of the FAK signaling pathway. Apigenin thus appears to inhibit the growth and migration of hypertrophic scar fibroblasts by inhibiting FAK signaling. This suggests apigenin could potentially provide a new option for the treatment of hypertrophic scars.

Experimental Study on the Influence of Apigenin K and Melatonin in Socket Preservation as Bone Stimulators: An Experimental Study in Beagle Dogs

The aim is to evaluate whether apigenin K and melatonin M5250 were able to stimulate bone formation after tooth extraction at one, two, and three months follow-up. Six male beagle dogs were used. Apigenin K and melatonin M5250 immersed in hemostatic collagen sponges were placed in the third and fourth premolar and the first molar extracted sockets; the second premolar was used as control. At one, two, and three months, bone core biopsies were performed, and picrosirius–hematoxylin was used for the staining process. In the first month, a higher amount of calcified bone tissue was observed in the melatonin (77.87% ± 1.2%) and apigenin K (69.81% ± 1.8%) groups than the control group (57.27% ± 0.54%), with apparent discrepancies in values between the three groups (p < 0.04). In the second month, there was a considerable improvement in the results in the areas with melatonin (79.81% ± 0.11%) than in those of apigenin K (71.65% ± 0.52%) and control (64.77% ± 0.44%) (p < 0.04). In the third month, the number of mature bone was similar to all the groups. The creation of new bone was significant in the melatonin group (82.78% ± 0.87%), followed by the apigenin K group (78.76% ± 0.43%) and the control group (57.27% ± 0.11%). From this experimental study in dogs, it can be concluded that melatonin and apigenin K can accelerate the process of mineralization of the bone matrix, and thus the creation of laminae in the early stages of healing (1 month). Less reabsorption of the post-extraction sockets can be expected with the topical application of melatonin and apigenin K. It seems that the stimulatory effects of bone healing induced by the topical application of melatonin and apigenin K are defect-size-dependent, being more evident in small defects compared to larger defects.

Apigenin, A Plant Flavone Playing Noble Roles in Cancer Prevention Via Modulation of Key Cell Signaling Networks

Background:

Cancer is a global health problem and the continuous rise in incidence and mortality due to cancer carries a real economic burden to all countries. Accumulation of genetic mutation, exposure of environmental carcinogens and food habits due to change in lifestyles are the key reasons for cancer. Targeting cancer cells, we need a multitargeting molecule with low/no toxicity.

Objective :

To review the current update of the research status of chemopreventive/therapeutic molecule, Apigenin.

Methods:

Compare the results of the published articles and granted patents on this compound. We also discuss the pros and cons of the present research and future direction.

Results:

Cancer cells have characteristic alterations and dysregulation of various cell signaling pathways that control cell homeostasis, proliferation, motility, and survival in normal cells. Natural flavonoids are the compounds well known for their anti-inflammatory, anti-oxidant, and anti-cancerous properties. Apigenin, along with several other physiological effects, has a very low intrinsic toxicity and striking effects on the proliferation of cancer cells. Interestingly, this multitargeting molecule is getting wide acceptance among researchers. It is evident from the recent patents filed in this compound. At present, three patents have been granted only on the anticancer properties of apigenin.

Conclusion:

This mini-review will explain the present research status of apigenin and will further shine some light on how apigenin performs its anti-cancerous actions by interfering with the key cellsignaling pathways.

Dietary Fucoxanthin Induces Anoikis in Colorectal Adenocarcinoma by Suppressing Integrin Signaling in a Murine Colorectal Cancer Model

Fucoxanthin (Fx), abundantly contained in edible brown algae, is a carotenoid with strong anti-cancer potential. Anoikis is an anchor-dependent apoptosis particularly related to integrin signaling, and a target for cancer preventive strategies. We recently demonstrated that Fx prevented colon cancer in azoxymethane-dextrane sodium sulfate (AOM/DSS) carcinogenic model mice, and that it increased anoikis-like integrin β1^low/-/cleaved caspase-3^high cells in colonic mucosal crypts. However, an induction mechanism of anoikis by Fx in adenocarcinoma tissue remains unresolved. Thus, we investigated anoikis in colonic adenocarcinoma in AOM/DSS mice. Fx administration (30 mg/kg body weight) significantly suppressed the incidence and multiplicity of colonic adenocarcinoma in AOM/DSS mice. A number of anoikis-like integrin β1^low/-/cleaved caspase-3^high cells in colonic adenocarcinoma and mucosal crypts were significantly increased, 8.3- and 3.5-fold in the Fx group compared with those of the control group, respectively. The results indicated the increase of anoikis-like cells occurred more strongly in colonic adenocarcinoma than in colonic mucosal crypts. In addition, integrin β1 expression, and pFAK (Tyr³⁹⁷) and pPaxillin (Tyr³¹) activation in mucosal tissue decreased 0.7-, 0.5- and 0.6-fold by Fx administration, respectively. The results suggest that Fx induces anoikis in colonic adenocarcinoma developed by AOM/DSS treatment through attenuation of integrin signaling.

Function of flavonoids on different types of programmed cell death and its mechanism: a review

Cell death in the living system plays a vital role in maintaining the homeostasis and balancing the cell count in the body. Programmed cell death (PCD) is a crucial component of several development and defense mechanisms. PCD is also important in terms of aging which avoids the accumulation of cellular damage by maintaining cell division. Depending on the execution of cell death and its role in destruction, PCD is categorized into several subtypes. The major different forms of PCD in animals are apoptosis, autophagy and necrosis, which can be distinct in morphological terms. More intense investigations of cell death have given close insight showing other important types of cellular destruction and their pivotal roles in treating disease conditions like cancer. Flavonoids have been acquired a great interest for disease therapies and chemoprevention through activation of several PCD mechanisms. The significant potential of natural flavonoids in the induction of distinct signaling cascades is being a massive approach for targeting uncontrolled cell growth. For these reasons, understanding PCD mechanisms is a promising approach for the interventions in treating cancer. Thus, it is intriguing that understanding the different forms of PCD mechanism induced by flavonoids with more accurate descriptions on the biochemical and cellular processes are gaining more significance in cancer research. Here, we provide a brief overview on the different types of PCD and aim to discuss the functional role of flavonoids in promoting different types of cell death as well as an extensive brief review on their mechanism of action has been highlighted.

Unraveling the molecular mechanisms and the potential chemopreventive/therapeutic properties of natural compounds in melanoma

Melanoma is the most fatal form of skin cancer. Current therapeutic approaches include surgical resection, chemotherapy, targeted therapy and immunotherapy. However, these treatment strategies are associated with development of drug resistance and severe side effects. In recent years, natural compounds have also been extensively studied for their anti-melanoma effects, including tumor growth inhibition, apoptosis induction, angiogenesis and metastasis suppression and cancer stem cell elimination. Moreover, a considerable number of studies reported the synergistic activity of phytochemicals and standard anti-melanoma agents, as well as the enhanced effectiveness of their synthetic derivatives and novel formulations. However, clinical data confirming these promising effects in patients are still scanty. This review emphasizes the anti-tumor mechanisms and potential application of the most studied natural products for melanoma prevention and treatment.

Autophagy, anoikis, ferroptosis, necroptosis, and endoplasmic reticulum stress: Potential applications in melanoma therapy

Melanoma as the most major skin malignancy has attracted much attention, so far. Although a successful therapeutic strategy requires an accurate understanding of the precise mechanisms for the initiation and progression of the melanoma. Several types of cell death mechanisms have recently been identified along with conventional cell death mechanisms such as apoptosis and necrosis. Among those mechanisms, necroptosis, anoikis, ferroptosis, and autophagy may be considered to have remarkable modulatory impacts on melanoma. In the present review, we explain the mechanisms of cell death signaling pathways related to autophagy, ferroptosis, anoikis, necroptosis, and reticulum endoplasmic stress in cells and describe how those mechanisms transduce signals in melanoma cells. Meanwhile, we describe how we can modulate those mechanisms to eliminate melanoma.

A Comprehensive Assessment of Apigenin as an Antiproliferative, Proapoptotic, Antiangiogenic and Immunomodulatory Phytocompound

Apigenin (4′,5,7-trihydroxyflavone) (Api) is an important component of the human diet, being distributed in a wide number of fruits, vegetables and herbs with the most important sources being represented by chamomile, celery, celeriac and parsley. This study was designed for a comprehensive evaluation of Api as an antiproliferative, proapoptotic, antiangiogenic and immunomodulatory phytocompound. In the set experimental conditions, Api presents antiproliferative activity against the A375 human melanoma cell line, a G2/M arrest of the cell cycle and cytotoxic events as revealed by the lactate dehydrogenase release. Caspase 3 activity was inversely proportional to the Api tested doses, namely 30 μM and 60 μM. Phenomena of early apoptosis, late apoptosis and necrosis following incubation with Api were detected by Annexin V-PI double staining. The flavone interfered with the mitochondrial respiration by modulating both glycolytic and mitochondrial pathways for ATP production. The metabolic activity of human dendritic cells (DCs) under LPS-activation was clearly attenuated by stimulation with high concentrations of Api. Il-6 and IL-10 secretion was almost completely blocked while TNF alpha secretion was reduced by about 60%. Api elicited antiangiogenic properties in a dose-dependent manner. Both concentrations of Api influenced tumour cell growth and migration, inducing a limited tumour area inside the application ring, associated with a low number of capillaries.

Botanical Therapeutics: Phytochemical Screening and Biological Assessment of Chamomile, Parsley and Celery Extracts against A375 Human Melanoma and Dendritic Cells

Chamomile, parsley, and celery represent major botanical sources of apigenin, a well-known flavone with chemopreventive properties. The aim of this study was to assess the phytochemical composition, antioxidant, and anti-inflammatory potential of methanol extracts obtained from chamomile, parsley, and celery collected from Romania, as well as the biological activity against A375 human melanoma and human dendritic cells. Results have shown that all three extracts are rich in polyphenolic compounds and flavonoids, and they generate a radical scavenger capacity, iron chelation potential, as well as lipoxygenase inhibition capacity. Chamomile and celery extracts present weak antiproliferative and pro-apoptotic properties in the set experimental conditions, while parsley extract draws out significant pro-apoptotic potential against A375 human melanoma cells. Parsley and chamomile extracts affected the fibroblast-like morphology of the screened tumor cell line. On the other hand, chamomile and celery extracts abrogated the expansion of LPS-activated dendritic cells, while the metabolic activity was attenuated by stimulation with celery extract; chamomile and parsley extracts had no effect upon this parameter. Chamomile and parsley extracts incubation with naive dendritic cells did not trigger cytokine secretion (TNF-alpha, IL-6, IL-10), but celery extract stimulation significantly reduced the anti-inflammatory, cytokine IL-10.

Alpha-mangostin, an active compound in Garcinia mangostana, abrogates anoikis-resistance in human hepatocellular carcinoma cells

Anoikis-resistance is a critical step in cancer progression, especially during the process of metastasis. During this phase, the cancer phenotype that causes cell survival in detachment conditions, drug resistance, and epithelial-to-mesenchymal transition (EMT) is altered. Inhibition of anoikis-resistance can potentially be the molecular target in cancer therapy. Alpha-mangostin, an active compound in Garcinia mangostana, has been reported for its cell-death induction and its chemosensitizing and anti-metastatic properties in many cancer cell types, such as ovarian cancer, lung cancer, and hepatocellular carcinoma. We, therefore, have investigated whether alpha-mangostin could sensitize anoikis in human hepatocellular carcinoma (HepG2). The established anoikis-resistant HepG2 displayed more aggressive malignant behaviors, including rapid proliferation, doxorubicin resistance, up-regulated anti-apoptotic protein levels, and EMT phenotype. Alpha-mangostin significantly sensitized anoikis in HepG2 through the inhibition of cell survival by induced caspase-9, caspase-8 and caspase-3 activities, increased pro-apoptotic protein (Bax, Bim, t-Bid) levels, and decreased anti-apoptotic protein (c-FLIP, Mcl-1) levels. Besides, alpha-mangostin significantly reduced cell re-adhesion and migration, matrix metalloproteinases-2 (MMP-2) and MMP-9 secretions, and EMT-involved protein (N-cadherin, αV, β1 integrin, and vimentin) expressions. AKT and ERK signaling pathways were dramatically suppressed, which indicated that alpha-mangostin inhibited anoikis-resistance via the inhibition of these pathways in HepG2. These findings support the development of alpha-mangostin to be used in the treatment of anoikis-resistant liver cancer.

Small size fullerenol nanoparticles suppress lung metastasis of breast cancer cell by disrupting actin dynamics

BACKGROUND

Tumor metastasis is the primary cause of mortality in cancer patients. Migratory breast cancer cells in lymphatic and blood vessels seek new sites and form metastatic colonies in the lung and bone, and then these cancer cells often wreak considerable havoc. With advances in nanotechnology, nanomaterials and nanotechnologies are widely applied in tumor therapy. In this paper, small size fullerenol nanoparticles, which are separated by isoelectric focusing electrophoresis (IFE) for discrepancy of isoelectric point (pI), are used in the study of tumor metastasis.

RESULTS

In this study, the commendable inhibition of tumor metastasis was uncovered by intravenous injection of purified fullerenol fraction with special surface charge and functional groups, which was separated by IFE for discrepancy of pI. By investigating the actin dynamics in several cancer cell lines, we found these small size fullerenol nanoparticles disturbed actin dynamics. Young's modulus detection and cell migration assays revealed that fullerenol lowered stiffness and restrained migration of breast cancer cells. Filopodia, the main supporting structures of actin bundles, are important for cell motility and adhesion. Scanning electron microscopy showed that fullerenol reduced the number and length of filopodia. Simultaneously, the inhibition of integrin to form clusters on filopodias, which was likely induced by reorganizing of actin cytoskeleton, impacted cancer cell adhesion and motility.

CONCLUSIONS

With intravenous injection of these fullerenol nanoparticles, tumor metastasis is well inhibited in vivo. The underlying mechanism most likely to be attributed to the effect of fullerenol nanoparticles on disturbing actin dynamics. With the disordered actin fiber, cell function is varied, including decreased cell stiffness, reduced filopodia formation, and inactivated integrin.

MiR-7a is an important mediator in Fas-associated protein with death domain (FADD)-regulated expression of focal adhesion kinase (FAK)

Fas-associated protein with death domain (FADD), a classical adaptor protein mediating apoptotic stimuli-induced cell death, has been reported to engage in several non-apoptotic processes such as T cell and cardiac development and tumorigenesis. Recently, there are several reports about the FADD's involvement in cell migration, however the underlying mechanism remains elusive. Here, we present a new finding that FADD could regulate the expression of FAK, a non-receptor protein tyrosine kinase overexpressed in many cancers, and played an important role in cell migration in murine MEF and melanoma cells with different metastatic potential, B16F10 and B16F1. Moreover, miR-7a, a tumor suppressor which prohibits cell migration and invasion, was up-regulated in FADD-deficient cells. And FAK was verified to be the direct target gene of miR-7a in B16F10 cells. Furthermore, we demonstrate that miR-7a was a necessary mediator in FADD-regulated FAK expression. In contrast to its classical apoptotic role, FADD interference could reduce the rate of cell migration, which could be rescued by inhibiting miR-7a expression. Taken together, our data provide a novel explanation regarding how FADD regulates cell migration in murine melanoma cells.

SRVF, a novel herbal formula including Scrophulariae Radix and Viticis Fructus, disrupts focal adhesion and causes detachment-induced apoptosis in malignant cancer cells

When cells lose adhesion, they undergo detachment-induced apoptosis, known as anoikis. In contrast, tumor cells acquire resistance to anoikis, enabling them to survive, even after separating from neighboring cells or the ECM. Therefore, agents that restore anoikis sensitivity may serve as anti-cancer candidates. In this study, we constructed a novel herbal formula, SRVF, which contains Scrophulariae Radix (SR) and Viticis Fructus (VF). SRVF rapidly decreased cell adhesion, altered the cell morphology to round, and induced cell death; however, SR, VF, or their co-treatment did not. SRVF arrested HT1080 cells in G₂/M phase, increased the levels of pro-apoptotic proteins, and decreased the levels of anti-apoptotic proteins. Furthermore, SRVF efficiently reduced cell-cell and cell-ECM interactions by disrupting the F-actin cytoskeleton and down-regulating the levels of focal adhesion-related proteins, suggesting that SRVF efficiently triggers detachment-induced apoptosis (i.e., anoikis) in malignant cancer cells. In xenograft mouse models, daily oral administration of 50 or 100 mg/kg SRVF retarded tumor growth in vivo, and repeated administration of SRVF did not cause systemic toxicity in normal mice. These data collectively indicate that SRVF induces cancer cell death by restoring anoikis sensitivity via disrupting focal adhesion. Therefore, SRVF may be a safe and potent anti-cancer herbal decoction.

Apigenin in cancer therapy: anti-cancer effects and mechanisms of action

Apigenin is a common dietary flavonoid that is abundantly present in many fruits, vegetables and Chinese medicinal herbs and serves multiple physiological functions, such as strong anti-inflammatory, antioxidant, antibacterial and antiviral activities and blood pressure reduction. Therefore, apigenin has been used as a traditional medicine for centuries. Recently, apigenin has been widely investigated for its anti-cancer activities and low toxicity. Apigenin was reported to suppress various human cancers in vitro and in vivo by multiple biological effects, such as triggering cell apoptosis and autophagy, inducing cell cycle arrest, suppressing cell migration and invasion, and stimulating an immune response. In this review, we focus on the most recent advances in the anti-cancer effects of apigenin and their underlying mechanisms, and we summarize the signaling pathways modulated by apigenin, including the PI3K/AKT, MAPK/ERK, JAK/STAT, NF-κB and Wnt/β-catenin pathways. We also discuss combinatorial strategies to enhance the anti-cancer effect of apigenin on various cancers and its use as an adjuvant chemotherapeutic agent to overcome cancer drug resistance or to alleviate other adverse effects of chemotherapy. The functions of apigenin against cancer stem cells are also summarized and discussed. These data demonstrate that apigenin is a promising reagent for cancer therapy. Apigenin appears to have the potential to be developed either as a dietary supplement or as an adjuvant chemotherapeutic agent for cancer therapy.

Apigenin Inhibits Human SW620 Cell Growth by Targeting Polyamine Catabolism

Apigenin is a nonmutagenic flavonoid that has antitumor properties. Polyamines are ubiquitous cellular polycations, which play an important role in the proliferation and differentiation of cancer cells. Highly regulated pathways control the biosynthesis and degradation of polyamines. Ornithine decarboxylase (ODC) is the rate-limiting enzyme in the metabolism, and spermidine/spermine-N1-Acetyl transferase (SSAT) is the rate-limiting enzyme in the catabolism of polyamines. In the current study, the effect of increasing concentrations of apigenin on polyamine levels, ODC and SSAT protein expression, mRNA expression, cell proliferation and apoptosis, and the production of reactive oxygen species (ROS) was investigated in SW620 colon cancer cells. The results showed that apigenin significantly reduced cell proliferation, decreased the levels of spermidine and spermine, and increased previously downregulated putrescine contents. Apigenin also enhanced SSAT protein and mRNA levels and the production of reactive oxygen species in SW620 cells, though it had no significant effect on the levels of ODC protein or mRNA. Apigenin appears to decrease the proliferation rate of human SW620 cells by facilitating SSAT expression to induce polyamine catabolism and increasing ROS levels to induce cell apoptosis.

miR-10a suppresses colorectal cancer metastasis by modulating the epithelial-to-mesenchymal transition and anoikis

MicroRNAs (miRNAs) have a critical role in tumorigenesis and metastasis, which are major obstacles of cancer therapy. However, the role of miRNAs in colorectal cancer (CRC) metastasis remains poorly understood. Here, we found that miRNA-10a (miR-10a) was upregulated in primary CRC tissues and cell line (SW480) derived from primary CRC compared with metastatic cancer tissues in lymph node and cell line (SW620). The differential expression of miR-10a was inversely correlated with distant metastasis and invasion depth. miR-10a promoted migration and invasion in vitro but inhibited metastasis in vivo by regulating the epithelial-to-mesenchymal transition and anoikis. Furthermore, matrix metalloproteinase 14 (MMP14) and actin gamma 1 (ACTG1) were validated as target genes of miR-10a in CRC cells. Ectopic expression of MMP14 and ACTG1 counteracted the decreased cell adhesion and anoikis resistance activities induced by miR-10a. These findings not only describe the mechanism by which miR-10a suppresses CRC metastasis but also suggest the potential prognostic and therapeutic value of miR-10a in CRC patients.

Morus alba Leaf Lectin (MLL) Sensitizes MCF-7 Cells to Anoikis by Inhibiting Fibronectin Mediated Integrin-FAK Signaling through Ras and Activation of P38 MAPK

Lectins are a unique class of carbohydrate binding proteins/glycoproteins, and many of them possess anticancer properties. They can induce cell cycle arrest and apoptosis, inhibit protein synthesis, telomerase activity and angiogenesis in cancer cells. In the present study, we have demonstrated the effect of Morus alba leaf lectin (MLL) on anoikis induction in MCF-7 cells. Anoikis induction in cancer cells has a significant role in preventing early stage metastasis. MLL treatment in monolayers of MCF-7 cells caused significant detachment of cells in a time and concentration dependent manner. The detached cells failed to re-adhere and grew even to culture plates coated with different matrix proteins. DNA fragmentation, membrane integrity studies, annexin V staining, caspase 9 activation and upregulation of Bax/Bad confirmed that the detached cells underwent apoptosis. Upregulation of matrix metalloproteinase 9 (MMP-9) caused a decrease in fibronectin (FN) production which facilitated the cells to detach by blocking the FN mediated downstream signaling. On treatment with MLL, we have observed downregulation of integrin expression, decreased phosphorylation of focal adhesion kinase (FAK), loss in FAK-integrin interaction and active Ras. MLL treatment downregulated the levels of phosphorylated Akt and PI3K. Also, we have studied the effect of MLL on two stress activated protein kinases p38 MAPK and JNK. p38 MAPK activation was found to be elevated, but there was no change in the level of JNK. Thus our study substantiated the possible antimetastatic effect of MLL by inducing anoikis in MCF-7 cells by activation of caspase 9 and proapoptotic Bax/Bad by blockage of FN mediated integrin/FAK signaling and partly by activation of p38 MAPK.

Potential therapeutic targets of epithelial-mesenchymal transition in melanoma

Melanoma is a cutaneous neoplastic growth of melanocytes with great potential to invade and metastasize, especially when not treated early and effectively. Epithelial-mesenchymal transition (EMT) is the process by which melanocytes lose their epithelial characteristics and acquire mesenchymal phenotypes. Mesenchymal protein expression increases the motility, invasiveness, and metastatic potential of melanoma. Many pathways play a role in promotion of mesenchymal protein expression including RAS/RAF/MEK/ERK, PI3K/AKT/mTOR, Wnt/β-catenin, and several others. Downstream effectors of these pathways induce expression of EMT transcription factors including Snail, Slug, Twist, and Zeb that promote repression of epithelial and induction of mesenchymal character. Emerging research has demonstrated that a variety of small molecule inhibitors as well as phytochemicals can influence the progression of EMT and may even reverse the process, inducing re-expression of epithelial markers. Phytochemicals are of particular interest as supplementary treatment options because of their relatively low toxicities and anti-EMT properties. Modulation of EMT signaling pathways using synthetic small molecules and phytochemicals is a potential therapeutic strategy for reducing the aggressive progression of metastatic melanoma. In this review, we discuss the emerging pathways and transcription factor targets that regulate EMT and evaluate potential synthetic small molecules and naturally occurring compounds that may reduce metastatic melanoma progression.