Cytostatic and cytotoxic activity of synthetic genistein glycosides against human cancer cell lines

Multi-Anticancer Activities of Phytoestrogens in Human Osteosarcoma

Phytoestrogens are plant-derived bioactive compounds with estrogen-like properties. Their potential health benefits, especially in cancer prevention and treatment, have been a subject of considerable research in the past decade. Phytoestrogens exert their effects, at least in part, through interactions with estrogen receptors (ERs), mimicking or inhibiting the actions of natural estrogens. Recently, there has been growing interest in exploring the impact of phytoestrogens on osteosarcoma (OS), a type of bone malignancy that primarily affects children and young adults and is currently presenting limited treatment options. Considering the critical role of the estrogen/ERs axis in bone development and growth, the modulation of ERs has emerged as a highly promising approach in the treatment of OS. This review provides an extensive overview of current literature on the effects of phytoestrogens on human OS models. It delves into the multiple mechanisms through which these molecules regulate the cell cycle, apoptosis, and key pathways implicated in the growth and progression of OS, including ER signaling. Moreover, potential interactions between phytoestrogens and conventional chemotherapy agents commonly used in OS treatment will be examined. Understanding the impact of these compounds in OS holds great promise for developing novel therapeutic approaches that can augment current OS treatment modalities.

Therapeutic vulnerabilities of cancer stem cells and effects of natural products

Covering: 1995 to 2022Tumors possess both genetic and phenotypic heterogeneity leading to the survival of subpopulations post-treatment. The term cancer stem cells (CSCs) describes a subpopulation that is resistant to many types of chemotherapy and which also possess enhanced migratory and anchorage-independent growth capabilities. These cells are enriched in residual tumor material post-treatment and can serve as the seed for future tumor re-growth, at both primary and metastatic sites. Elimination of CSCs is a key goal in enhancing cancer treatment and may be aided by application of natural products in conjunction with conventional treatments. In this review, we highlight molecular features of CSCs and discuss synthesis, structure-activity relationships, derivatization, and effects of six natural products with anti-CSC activity.

Research Progress on Structural Modification of Effective Antitumor Active Ingredients in Licorice

Licorice, a widely used traditional Chinese medicine, contains more than 300 flavonoids and more than 20 triterpenoids, which have potential medicinal value and can prevent the growth of tumor cells by blocking the cell cycle, affecting the regulation of the apoptosis gene of tumor cells, and inhibiting tumor cell angiogenesis. However, many of the compounds in licorice still have the drawbacks of poor solubility, significant toxic side effects, and low antitumor activity. This article reviews the structural modification of effective antitumor active ingredients in licorice, thus providing a theoretical basis for further investigation of licorice and the development of new antitumor drugs.

Application of Polyphenols and Flavonoids in Oncological Therapy

The use of naturally derived drugs in anti-cancer therapies has grown exponentially in recent years. Among natural compounds, polyphenols have shown potential therapeutic applications in treatment due to their protective functions in plants, their use as food additives, and their excellent antioxidant properties, resulting in beneficial effects on human health. Building more efficient cancer therapies with fewer side effects on human health can be achieved by combining natural compounds with conventional drugs, which are typically more aggressive than natural chemicals with polyphenols. This article reviews a wide variety of studies where polyphenolic compounds can play a key role as anticancer drugs, alone or in combination with other drugs. Moreover, the future directions of applications of various polyphenols in cancer therapy are shown.

Synthesis and Chemopreventive Potential of 5-FU/Genistein Hybrids on Colorectal Cancer Cells

A series of 5-FU-Genistein hybrids were synthesized and their structures were elucidated by spectroscopic analysis. The chemopreventive potential of these compounds was evaluated in human colon adenocarcinoma cells (SW480 and SW620) and non-malignant cell lines (HaCaT and CHO-K1). Hybrid 4a displayed cytotoxicity against SW480 and SW620 cells with IC₅₀ values of 62.73 ± 7.26 µM and 50.58 ± 1.33 µM, respectively; compound 4g induced cytotoxicity in SW620 cells with an IC₅₀ value of 36.84 ± 0.71 µM. These compounds were even more selective than genistein alone, the reference drug (5-FU) and the equimolar mixture of genistein plus 5-FU. In addition, hybrids 4a and 4g induced time- and concentration-dependent antiproliferative activity and cell cycle arrest at the S-phase and G2/M. It was also observed that hybrid 4a induced apoptosis in SW620 cells probably triggered by the extrinsic pathway in response to the activation of p53, as evidenced by the increase in the levels of caspases 3/8 and the tumor suppressor protein (Tp53). Molecular docking studies suggest that the most active compound 4a would bind efficiently to proapoptotic human caspases 3/8 and human Tp53, which in turn could provide valuable information on the biochemical mechanism for the in vitro cytotoxic response of this compound in SW620 colon carcinoma cell lines. On the other hand, molecular dynamics (MD) studies provided strong evidence of the conformational stability of the complex between caspase-3 and hybrid 4a obtained throughout 100 ns all-atom MD simulation. Molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) analyses of the complex with caspase-3 showed that the interaction between the ligand and the target protein is stable. Altogether, the results suggest that the active hybrids, mainly compound 4a, might act by modulating caspase-3 activity in a colorectal cancer model, making it a privileged scaffold that could be used in future investigations.

Therapeutic potentials of genistein: New insights and perspectives

Genistein, a polyphenolic isoflavone compound found abundantly in soy or soy-based products, is widely consumed in the Asian population. Genistein has poor bioavailability, to overcome this problem many advanced nano-drug delivery carrier systems are designed to enhance its water solubility and stability. However, further research is required to develop more efficient bioavailability improvement strategies. Genistein is a phytoestrogen which has been associated with reducing the risk of cancer, cardiovascular disorders, and diabetes mellitus. This plant-based bioactive compound possesses numerous biological activities such as anti-oxidant, anti-inflammatory, anti-obesity, anti-cancer, cardioprotective, and anti-diabetic activities to treat various disease states. Genistein has been used as an active therapeutic agent in many medications. Moreover, several clinical trials are in the ongoing stage to develop more efficient treatment therapies, especially for cancer treatment. This article highlights the protective and therapeutic benefits of genistein in the treatment of different ailments, and more specifically elaborates on the anti-cancer potential of genistein regarding various types of cancers. PRACTICAL APPLICATIONS: Genistein possesses versatile biological activities, including anti-diabetic, anti-inflammatory, anti-oxidant, anti-obesity, and anti-angiogenic. The most studied activity is anti-cancer. Currently, a number of pre-clinical and clinical trials are being carried out on anti-neoplastic and cytotoxic activities of genistein to develop novel therapeutic agents with excellent anti-cancer potential for the treatment of various kinds of cancer. Moreover, many bioavailability enhancement strategies have been developed to improve the bioavailability of genistein. Genistein shows significant hypoglycemic effects alone or in combination with other anti-diabetic agents. Genistein in combination with other chemotherapeutic agents is used for the treatment of prostate, bone, colorectal, glioma, breast, and bladder cancer.

Elucidation of xenoestrogen metabolism by non-targeted, stable isotope-assisted mass spectrometry in breast cancer cells

Environmental exposure to xenoestrogens, i.e., chemicals that imitate the hormone 17β-estradiol, has the potential to influence hormone homeostasis and action. Detailed knowledge of xenobiotic biotransformation processes in cell models is key when transferring knowledge learned from in vitro models to in vivo relevance. This study elucidated the metabolism of two naturally-occurring phyto- and mycoestrogens; namely genistein and zearalenone, in an estrogen receptor positive breast cancer cell line (MCF-7) with the aid of stable isotope-assisted metabolomics and the bioinformatic tool MetExtract II. Metabolism was studied in a time course experiment after 2 h, 6 h and 24 h incubation. Twelve and six biotransformation products of zearalenone and genistein were detected, respectively, clearly demonstrating the abundant xenobiotic biotransformation capability of the cells. Zearalenone underwent extensive phase-I metabolism resulting in α-zearalenol (α-ZEL), a molecule known to possess a significantly higher estrogenicity, and several phase-II metabolites (sulfo- and glycoconjugates) of the native compound and the major phase I metabolite α-ZEL. Moreover, potential adducts of zearalenone with a vitamin and several hydroxylated metabolites were annotated. Genistein metabolism resulted in sulfation, combined sulfation and hydroxylation, acetylation, glucuronidation and unexpectedly adduct formation with pentose- and hexose sugars. Kinetics of metabolite formation and subsequent excretion into the extracellular medium revealed a time-dependent increase in most biotransformation products. The untargeted elucidation of biotransformation products formed during cell culture experiments enables an improved and more meaningful interpretation of toxicological assays and has the potential to identify unexpected or unknown metabolites.

Cytotoxicity of synthetic derivatives against breast cancer and multi-drug resistant breast cancer cell lines: a literature-based perspective study

Cancer is the second most killer worldwide causing millions of people to lose their lives every year. In the case of women, breast cancer takes away the highest proportion of mortality rate than other cancers. Due to the mutation and resistance-building capacity of different breast cancer cell lines against conventional therapies, this death rate is on the verge of growth. New effective therapeutic compounds and treatment method is the best way to look out for in this critical time. For instance, new synthetic derivatives/ analogues synthesized from different compounds can be a ray of hope. Numerous synthetic compounds have been seen enhancing the apoptosis and autophagic pathway that directly exerts cytotoxicity towards different breast cancer cell lines. To cease the ever-growing resistance of multi-drug resistant cells against anti-breast cancer drugs (Doxorubicin, verapamil, tamoxifen) synthetic compounds may play a vital role by increasing effectivity, showing synergistic action. Many recent and previous studies have reported that synthetic derivatives hold potentials as an effective anti-breast cancer agent as they show great cytotoxicity towards cancer cells, thus can be used even vastly in the future in the field of breast cancer treatment. This review aims to identify the anti-breast cancer properties of several synthetic derivatives against different breast cancer and multi-drug-resistant breast cancer cell lines with their reported mechanism of action and effectivity.

Potential of natural products in osteosarcoma treatment: Focus on molecular mechanisms

Osteosarcoma is the most frequent type of bone cancer found in children and adolescents, and commonly arises in the metaphyseal region of tubular long bones. Standard therapeutic approaches, such as surgery, chemotherapy, and radiation therapy, are used in the management of osteosarcoma. In recent years, the mortality rate of osteosarcoma has decreased due to advances in treatment methods. Today, the scientific community is investigating the use of different naturally derived active principles against various types of cancer. Natural bioactive compounds can function against cancer cells in two ways. Firstly they can act as classical cytotoxic compounds by non-specifically affecting macromolecules, such as DNA, enzymes, and microtubules, which are also expressed in normal proliferating cells, but to a greater extent by cancer cells. Secondly, they can act against oncogenic signal transduction pathways, many of which are activated in cancer cells. Some bioactive plant-derived agents are gaining increasing attention because of their anti-cancer properties. Moreover, some naturally-derived compounds can significantly promote the effectiveness of standard chemotherapy drugs, and in certain cases are able to ameliorate drug-induced adverse effects caused by chemotherapy. In the present review we summarize the effects of various naturally-occurring bioactive compounds against osteosarcoma.

Inhibitory Effects of Genistein on Vascular Smooth Muscle Cell Proliferation Induced by Ox-LDL: Role of BKCa Channels

Background

Oxidized low-density lipoprotein (Ox-LDL) is a crucial pathogenic factor for vascular diseases, which can induce the proliferation of vascular smooth muscle cells (VSMCs). Genistein is the main component of soybean isoflavone. Genistein has a variety of pharmacological properties in the treatment of vascular diseases and a promising clinical application. Large-conductance calcium-activated potassium (BKCa) channels are the primary type of potassium channels in VSMCs, which regulate various biological functions of VSMCs. However, whether genistein exerts an antiproliferation effect on Ox-LDL-stimulated VSMCs remains unclear. The current study is aimed at elucidating the effect of genistein on the Ox-LDL-stimulated proliferation of VSMCs and its possible molecular mechanism, especially the electrophysiological mechanism related to BKCa channels.

Methods

Monoculture VSMC was obtained by an acute enzyme-dispersing method. The proliferation of cells was measured by CCK-8, cell cycle, and proliferating cell nuclear antigen (PCNA) expression. The BKCa whole-cell currents were measured by patch-clamp.

Results

Ox-LDL treatment induced the proliferation of VSMCs, upregulated the BKCa protein expression, and increased the density of BKCa currents, while genistein significantly inhibited these effects caused by Ox-LDL. BKCa channels exerted a regulatory role in the proliferation of VSMCs in response to Ox-LDL. The inhibition of BKCa channels suppressed Ox-LDL-stimulated VSMC proliferation, while the activation of BKCa channels showed the opposite effect. Moreover, genistein suppressed the activity of BKCa, including protein expression and current density in a protein tyrosine kinase- (PTK-) dependent manner.

Conclusion

This study demonstrated that genistein inhibited the Ox-LDL-mediated proliferation of VSMCs by blocking the cell cycle progression; the possible molecular mechanism may be related to PTK-dependent suppression of BKCa channels. Our results provided novel ideas for the application of genistein in the treatment of vascular diseases and proposed a unique insight into the antiproliferative molecular mechanism of genistein.

Recent Advances in Characterizing Natural Products that Regulate Autophagy

Autophagy, an intricate response to nutrient deprivation, pathogen infection, Endoplasmic Reticulum (ER)-stress and drugs, is crucial for the homeostatic maintenance in living cells. This highly regulated, multistep process has been involved in several diseases including cardiovascular and neurodegenerative diseases, especially in cancer. It can function as either a promoter or a suppressor in cancer, which underlines the potential utility as a therapeutic target. In recent years, increasing evidence has suggested that many natural products could modulate autophagy through diverse signaling pathways, either inducing or inhibiting. In this review, we briefly introduce autophagy and systematically describe several classes of natural products that implicated autophagy modulation. These compounds are of great interest for their potential activity against many types of cancer, such as ovarian, breast, cervical, pancreatic, and so on, hoping to provide valuable information for the development of cancer treatments based on autophagy.

A new lipophilic amino alcohol, chemically similar to compound FTY720, attenuates the pathogenesis of experimental autoimmune encephalomyelitis by PI3K/Akt pathway inhibition

Experimental autoimmune encephalomyelitis (EAE) is one of the main animal models used for the study of Multiple Sclerosis (MS). Long-chain lipophilic amino alcohols with immunoregulatory activities have already been studied in some models of inflammatory diseases, but the action of these compounds in EAE and MS is still unknown. In this study, we investigated whether the lipophilic amino alcohol 4b would act to improve the clinical signs of EAE and reduce the demyelination process and the neuroinflammatory parameters in the spinal cord, as well as the inflammatory process in the inguinal lymph nodes, of C57Bl/6 mice induced with EAE after stimulation with MOG_35-55 and pertussis toxin. The 4b treatment (1.0 mg/kg/day) was orally administered, starting on the day of onset of clinical signs of the disease (10th) and ending on the 20th day after immunization. This treatment was able to reduce the cell count on the inguinal lymph nodes, the migration of inflammatory cells into the central nervous system (CNS), as well as the processes of microgliosis, astrogliosis, and the production of chemokines and pro-inflammatory cytokines, thus increasing the IL-10 anti-inflammatory cytokine levels in EAE mice. The inhibition of Akt phosphorylation in the CNS of EAE mice after treatment with 4b indicates that the immunoregulatory action of 4b is related to the PI3K/Akt signaling pathway. Our results indicate the immunoregulatory efficacy of the new compound 4b in the control of some inflammatory parameters and in the glial proliferation. In addition, 4b was able to reduce the demyelination of neurons and the worsening of clinical signs of EAE as effectively as the compound FTY720, the first oral drug approved by the FDA for the treatment of MS.

Genistein as Potential Therapeutic Candidate for Menopausal Symptoms and Other Related Diseases

Plant-derived compounds have recently attracted greater interest in the field of new therapeutic agent development. These compounds have been widely screened for their pharmacological effects. Polyphenols, such as soy-derived isoflavones, also called phytoestrogens, have been extensively studied due to their ability to inhibit carcinogenesis. These compounds are chemically similar to 17β-estradiol, and mimic the binding of estrogens to its receptors, exerting estrogenic effects in target organs. Genistein is an isoflavone derived from soy-rich products and accounts for about 60% of total isoflavones found in soybeans. Genistein has been reported to exhibit several biological effects, such as anti-tumor activity (inhibition of cell proliferation, regulation of the cell cycle, induction of apoptosis), improvement of glucose metabolism, impairment of angiogenesis in both hormone-related and hormone-unrelated cancer cells, reduction of peri-menopausal and postmenopausal hot flashes, and modulation of antioxidant effects. Additionally, epidemiological and clinical studies have reported health benefits of genistein in many chronic diseases, such as cardiovascular disease, diabetes, and osteoporosis, and aid in the amelioration of typical menopausal symptoms, such as anxiety and depression. Although the biological effects are promising, certain limitations, such as low bioavailability, biological estrogenic activity, and effects on target organs, have limited the clinical applications of genistein to some extent. Moreover, studies report that modification of its molecular structure may eliminate the biological estrogenic activity and its effects on target organs. In this review, we summarize the potential benefits of genistein on menopause symptoms and menopause-related diseases like cardiovascular, osteoporosis, obesity, diabetes, anxiety, depression, and breast cancer.

Polyphenols in Colorectal Cancer: Current State of Knowledge including Clinical Trials and Molecular Mechanism of Action

Polyphenols have been reported to have wide spectrum of biological activities including major impact on initiation, promotion, and progression of cancer by modulating different signalling pathways. Colorectal cancer is the second most major cause of mortality and morbidity among females and the third among males. The objective of this review is to describe the activity of a variety of polyphenols in colorectal cancer in clinical trials, preclinical studies, and primary research. The molecular mechanisms of major polyphenols related to their beneficial effects on colorectal cancer are also addressed. Synthetic modifications and other future directions towards exploiting of natural polyphenols against colorectal cancer are discussed in the last section.

Dietary Soy Isoflavone: A Mechanistic Insight

Soy, a major component of the diet for centuries contains the largest concentration of isoflavones, a class of phytoestrogens. A variety of health benefits are associated with the consumption of soy primarily because of the isoflavones genistein, daidzein, and glycitein with a potential protective effect against a number of chronic diseases. Owing to the pharmaceutical and nutraceutical properties allied with isoflavonoids and their use in functional foods, there is a growing interest in these compounds. This review throws light on the chemistry, and significant pharmacological and biopharmaceutical aspects of soy isoflavones. This article critically describes the mechanisms of action, infers conclusions and shows opportunity for future research.

Biosynthesis of natural and non-natural genistein glycosides

Biosynthesis of various genistein glycopyranoside scaffolds using versatile GTs and SOMTs. Each compound was structurally characterized and biological activity assay was carried out.

Isoflavones, their Glycosides and Glycoconjugates. Synthesis and Biological Activity

Glycosylation of small biologically active molecules, either of natural or synthetic origin, has a profound impact on their solubility, stability, and bioactivity, making glycoconjugates attractive compounds as therapeutic agents or nutraceuticals. A large proportion of secondary metabolites, including flavonoids, occur in plants as glycosides, which adds to the molecular diversity that is much valued in medicinal chemistry studies. The subsequent growing market demand for glycosidic natural products has fueled the development of various chemical and biotechnological methods of glycosides preparation. The review gives an extensive overview of the processes of the synthesis of isoflavones and discusses recently developed major routes towards isoflavone-sugar formation processes. Special attention is given to the derivatives of genistein, the main isoflavone recognized as a useful lead in several therapeutic categories, with particular focus on anticancer drug design. The utility of chemical glycosylations as well as glycoconjugates preparation is discussed in some theoretical as well as practical aspects. Since novel approaches to chemical glycosylations and glycoconjugations are abundant and many of them proved suitable for derivatization of polyphenols a new body of evidence has emerged, indicating that sugar moiety can play a much more significant role, when attached to a pharmacophore, then being a mere “solubilizer”. In many cases, it has been demonstrated that semisynthetic glycoconjugates are much more potent cytostatic and cytotoxic agents than reference isoflavones. Moreover, the newly designed glycosides or glycoside mimics can act through different mechanisms than the parent active molecule.

Cytotoxic activity of genistein-8-C-glucoside form Lupinus luteus L. and genistein against human SK-OV-3 ovarian carcinoma cell line

Genistein belongs to isoflavones, which are a subclass of flavonoids, a large group of polyphenolic compounds widely distributed in plants. Numerous in vitro studies suggest that isoflavones, particularly genistein, have both chemopreventive and chemotherapeutic potential in multiple tumor types. However, the molecular and cellular mechanisms of genistein effects on human ovarian cancer cells are still little known. In the present study, we investigated anticancer activity of genistein and its natural glucoside, genistein-8-C-glucoside isolated from flowers of Lupinus luteus L. We examined the effects of the two isoflavones alone or in combination on cultured human SK-OV-3 ovarian carcinoma cells. The cells were exposed to genistein and genistein-8-C-glucoside at various concentrations (1–90 µM) for 24 and 48 h. The cytotoxic and apoptotic properties of compounds were studied by the colorimetric 3-[4,5-2-yl]-2-5-diphenyltetrazolium bromide assay and the acridine orange/ethidium bromide staining technique. The morphological features of SK-OV-3 cells were examined by Nomarski differential interference contrast combined with a confocal laser scanning microscope. The level of ROS was evaluated with fluorescence probes: dichlorofluorescein-diacetate by flow cytometry. Changes in mitochondrial membrane potential were determined using 5,5,6,6-tetrachloro-1,1,3,3-tetraethylbenzimidazolcarbocyanine iodide. Genistein-treatment and genistein-8-C-glucoside-treatment resulted in the inhibition of cell proliferation, induction of apoptotic cell death and loss of mitochondrial membrane potential. The present data provide the first evidence in vitro that genistein-8-C-glucoside and combination genistein-genistein-8-C-glucoside could be a potential chemotherapeutic candidate for ovarian cancer therapy.

The Anti-Cancer Effect of Polyphenols against Breast Cancer and Cancer Stem Cells: Molecular Mechanisms

The high incidence of breast cancer in developed and developing countries, and its correlation to cancer-related deaths, has prompted concerned scientists to discover novel alternatives to deal with this challenge. In this review, we will provide a brief overview of polyphenol structures and classifications, as well as on the carcinogenic process. The biology of breast cancer cells will also be discussed. The molecular mechanisms involved in the anti-cancer activities of numerous polyphenols, against a wide range of breast cancer cells, in vitro and in vivo, will be explained in detail. The interplay between autophagy and apoptosis in the anti-cancer activity of polyphenols will also be highlighted. In addition, the potential of polyphenols to target cancer stem cells (CSCs) via various mechanisms will be explained. Recently, the use of natural products as chemotherapeutics and chemopreventive drugs to overcome the side effects and resistance that arise from using chemical-based agents has garnered the attention of the scientific community. Polyphenol research is considered a promising field in the treatment and prevention of breast cancer.

Oxidative Stress: A Promising Target for Chemoprevention

Cancer is a leading cause of death worldwide, and treating advanced stages of cancer remains clinically challenging. Epidemiological studies have shown that oxidants and free radicals induced DNA damage is one of the predominant causative factors for cancer pathogenesis. Hence, oxidants are attractive targets for chemoprevention as well as therapy. Dietary agents are known to exert an anti-oxidant property which is one of the most efficient preventive strategy in cancer progression. In this article, we highlight dietary agents can potentially target oxidative stress, in turn delaying, preventing, or treating cancer development. Some of these agents are currently in use in basic research, while some have been launched successfully into clinical trials.

Enhancement of anticancer potential of polyphenols by covalent modifications

As evidenced by a growing number of respective clinical trials, a promising and increasingly valued approach to cancer prevention is chemoprevention which is based on using synthetic, semisynthetic, or natural compounds with the aim of preventing, delaying, arresting, or reversing carcinogenesis. Research carried out in the last two decades indicates that natural polyphenols isolated from plants (as well as their derivatives and synthetic analogs) exhibit pleiotropic actions toward cancer cells and therefore they could be used in both cancer prevention and therapy. This review discusses selected covalent modifications of polyphenols as a means for increasing their anticancer potential in relation to the parent compounds. The modifications include hydroxylation, methylation, acylation, and galloylation, among others. They were demonstrated to enhance cytotoxic, pro-oxidant, antiproliferative, proapoptotic, proautophagic, and antimigratory activities of phenolics toward various cancer cell lines in vitro. Importantly, some derivatives proved to suppress tumor growth and metastasis in animal models more strongly than the parent compounds. Some of the above-mentioned covalent modifications were also shown to increase absorption and tissue distribution of tested phenolic compounds in vivo. Anticancer clinical trials with polyphenol derivatives therefore seem warranted.

The enhancing effect of genistein on apoptosis induced by trichostatin A in lung cancer cells with wild type p53 genes is associated with upregulation of histone acetyltransferase

Genistein has been shown to enhance the antitumor activity of trichostatin A (TSA) in human lung carcinoma A549 cells. However, whether the combined treatment exerts the same effect in other lung cancer cells is unclear. In the present study we first compared the enhancing effect of genistein on the antitumor effect of TSA in ABC-1, NCI-H460 (H460) and A549 cells. Second, we investigated whether the effects of genistein are associated with increased histone/non-histone protein acetylation. We found that the enhancing effect of genistein on cell-growth-arrest in ABC-1 cells (p53 mutant) was less than in A549 and H460 cells. Genistein enhanced TSA induced apoptosis in A549 and H460 cells rather than in ABC-1 cells. After silencing p53 expression in A549 and H460 cells, the enhancing effect of genistein was diminished. In addition, genistein increased TSA-induced histone H3/H4 acetylation in A549 and H460 cells. Genistein also increased p53 acetylation in H460 cells. The inhibitor of acetyltransferase, anacardic acid, diminished the enhancing effect of genistein on all TSA-induced histone/p53 acetylation and apoptosis. Genistein in combination with TSA increased the expression of p300 protein, an acetyltransferase, in A549 and NCI-H460 cells. Furthermore, we demonstrated that genistein also enhanced the antitumor effect of genistein in A549-tumor-bearing mice. Taken together, these results suggest that the enhancing effects of genistein on TSA-induced apoptosis in lung cancer cells were p53-dependent and were associated with histone/non-histone protein acetylation.

Isoflavone lupiwighteone induces cytotoxic, apoptotic, and antiangiogenic activities in DU-145 prostate cancer cells

Isoflavones constitute a large series of compounds found in many plants. They make up an important part of the diet and have a broad spectrum of biological activities such as cytotoxic and antitumor effects. Lupiwighteone (Lup) is an isoflavone-type compound. It is distributed widely in wild-growing plants such as Glycyrrhiza glabra, Lupinus, and Lotus pedunculatus. On the basis of existing research, Lup shows antioxidant and antimicrobial effects, but its antitumor activity has not been reported as yet. This study aimed to examine the antitumor activity of Lup, explore its antitumor mechanism in a human prostate carcinoma cell line (DU-145), and evaluate its antiangiogenetic activity in the human umbilical vein endothelial cell line (HUVEC). The results showed that Lup could inhibit the growth of DU-145 and HUVEC cells in a concentration-dependent and time-dependent manner by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. Flow cytometry analysis indicated that Lup could induce cell cycle arrest, cells apoptosis, mitochondrial membrane potential loss, and an increase in intracellular reactive oxygen species of DU-145 cells. Upregulation of Bax, cytochrome c, caspase-3, and PARP-1 protein expressions and downregulation of Bcl-2, procaspase-9, and p-Akt protein expressions were observed by western blot after the treatment of Lup. Furthermore, the effects of Lup on the cellular behavior of HUVECs were also investigated. Altogether, our data proved the anticancer and antiangiogenesis potential of Lup.

Genistein and cancer: current status, challenges, and future directions

Primary prevention through lifestyle interventions is a cost-effective alternative for preventing a large burden of chronic and degenerative diseases, including cancer, which is one of the leading causes of morbidity and mortality worldwide. In the past decade, epidemiologic and preclinical evidence suggested that polyphenolic phytochemicals present in many plant foods possess chemopreventive properties against several cancer forms. Thus, there has been increasing interest in the potential cancer chemopreventive agents obtained from natural sources, such as polyphenols, that may represent a new, affordable approach to curb the increasing burden of cancer throughout the world. Several epidemiologic studies showed a relation between a soy-rich diet and cancer prevention, which was attributed to the presence of a phenolic compound, genistein, present in soy-based foods. Genistein acts as a chemotherapeutic agent against different types of cancer, mainly by altering apoptosis, the cell cycle, and angiogenesis and inhibiting metastasis. Targeting caspases, B cell lymphoma 2 (Bcl-2)-associated X protein (Bax), Bcl-2, kinesin-like protein 20A (KIF20A), extracellular signal-regulated kinase 1/2 (ERK1/2), nuclear transcription factor κB (NF-κB), mitogen-activated protein kinase (MAPK), inhibitor of NF-κB (IκB), Wingless and integration 1 β-catenin (Wnt/β-catenin), and phosphoinositide 3 kinase/Akt (PI3K/Akt) signaling pathways may act as the molecular mechanisms of the anticancer, therapeutic effects of genistein. Genistein also shows synergistic behavior with well-known anticancer drugs, such as adriamycin, docetaxel, and tamoxifen, suggesting a potential role in combination therapy. This review critically analyzes the available literature on the therapeutic role of genistein on different types of cancer, focusing on its chemical features, plant food sources, bioavailability, and safety.

Synthesis and cytotoxicity of 2,3-enopyranosyl C-linked conjugates of genistein

A series of glycoconjugates, derivatives of genistein containing a C-glycosylated carbohydrate moiety, were synthesized and their anticancer activity was tested in vitro in the human cell lines HCT 116 and DU 145. The target compounds 15–17 were synthesized by treating ω-bromoalkyl C-glycosides derived from l-rhamnal (1) with a tetrabutylammonium salt of genistein. The new, metabolically stable analogs of previously studied O-glycosidic genistein derivatives inhibited proliferation of cancer cell lines through inhibition of the cell cycle.

Novel genistein derivatives induce cell death and cell cycle arrest through different mechanisms

Genistein is a natural compound belonging to isoflavone family of secondary plant metabolites, characterized by pleiotropic biological activity. Here we present the results of a study on new analogs and polysaccharide complexes of genistein as potent antiproliferative and cell death-inducing agents. Most potent were 2 analogs (i.e., IFG-027 and IFG-043) and 2 complexes (i.e., SPG-G and XG-G), which had higher or similar antiproliferative activity in comparison to genistein. However, these 2 analogs decreased the number of cells in G2/M phase in contrast to genistein and SPG-G complex. Genistein analogs, IFG-027 and IFG-043, and also SPG-G complex decreased mitochondrial membrane potential and induced the externalization of phosphatidylserine to the extracellular membrane site, which indicates the induction of apoptosis. Interestingly, genistein and its analogs induced caspase 3-activation supporting apoptotic mechanism of cell death but SPG-G supported caspase 3-independent apoptosis. XG-G complex probably did not induce cell death through the apoptotic pathway, as we did not find the externalization of phosphatidylserine and activation of caspase-3. After the treatment of HL-60 cells with genistein, SPG-G and XG-G formation of acidic vesicular organelle (AVO) was detected. In contrast, in the cells that were treated with genistein analogs IFG-027 and IFG-043, AVO formation was not observed.

Natural product MDM2 inhibitors: anticancer activity and mechanisms of action

The mdm2 oncogene has recently been suggested to be a valuable target for cancer therapy and prevention. Overexpression of mdm2 is often seen in various human cancers and correlates with high-grade, late-stage, and more treatment-resistant tumors. The MDM2-p53 auto-regulatory loop has been extensively investigated and is an attractive cancer target, which indeed has been the main focus of anti-MDM2 drug discovery. Much effort has been expended in the development of small molecule MDM2 antagonists targeting the MDM2-p53 interaction, and a few of these have advanced into clinical trials. However, MDM2 exerts its oncogenic activity through both p53-dependent and -independent mechanisms. Recently, there is an increasing interest in identifying natural MDM2 inhibitors; some of them have been shown to decrease MDM2 expression and activity in vitro and in vivo. These identified natural MDM2 inhibitors include a plethora of diverse chemical frameworks, ranging from flavonoids, steroids, and sesquiterpenes to alkaloids. In addition to a brief review of synthetic MDM2 inhibitors, this review focuses on natural product MDM2 inhibitors, summarizing their biological activities in vitro and in vivo and the underlying molecular mechanisms of action, targeting MDM2 itself, regulators of MDM2, and/or the MDM2-p53 interaction. These MDM2 inhibitors can be used alone or in combination with conventional treatments, improving the prospects for cancer therapy and prevention. Their complex and unique molecular architectures may provide a stimulus for developing synthetic analogs in the future.

C-Glycosidic Genistein Conjugates and Their Antiproliferative Activity

This paper presents our attempt to investigate scopes and the limitations of olefin cross-metathesis (CM) reaction in the synthesis of complex C-glycosides of genistein and evaluation of their antiproliferative activities. Novel genistein glycoconjugates were synthesized with the utility of CM reaction initiated by first and second generation of Grubbs catalysts. The relative reactivity of utilized olefins, based on categories proposed by Grubbs, was estimated.In vitroexperiments in cancer cell lines showed that the selected derivatives (3aand3f) exhibited higher antiproliferative potential than the parent compound, genistein, and were able to block the cell cycle in the G2/M phase. The observed mechanism of action of C-glycosidic derivatives was similar to the activity of their O-glycosidic counterparts. These compounds were stable in culture medium. The obtained results show that our approach to genistein modification with application of cross-metathesis reaction allowed to obtain stable glycoconjugates with improved anticancer potential, compared to the parent isoflavone.

Genistein Derivatives Regioisomerically Substituted at 7-O- and 4′-O- Have Different Effect on the Cell Cycle

Our previous studies on antiproliferative properties of genistein derivatives substituted at C7 hydroxyl group of the ring A revealed some compounds with antimitotic properties. The aim of this work was to synthesize their analogues substituted at the 4′-position of the ring B in genistein and to define their antiproliferative mechanism of action in selected cancer cell linesin vitro. C4′-substituted glycoconjugates were obtained in a three-step procedure: (1) alkylation with anω-bromoester; (2) deacylation; (3) Ferrier-type rearrangement glycosylation with acylated glycals. Biological effects including antiproliferative effects of the compounds, cell cycle, DNA lesions (ATM activation, H2A.X phosphorylation, and micronuclei formation), and autophagy were studied in human cancer cell lines. Some of the tested derivatives potently inhibited cell proliferation. The presence of a substituent at the 4′-position of the ring B in genistein correlated to a p53-independent G1 cell-cycle arrest. The derivatives substituted at C4′ did not induce DNA lesions and appeared to be nongenotoxic. The tested compounds induced autophagy and caused remarkable decrease of cell volume.

A genistein derivative, ITB-301, induces microtubule depolymerization and mitotic arrest in multidrug-resistant ovarian cancer

Purpose

To investigate the mechanistic basis of the anti-tumor effect of the compound ITB-301.

Methods

Chemical modifications of genistein have been introduced to improve its solubility and efficacy. The anti-tumor effects were tested in ovarian cancer cells using proliferation assays, cell cycle analysis, immunofluorescence, and microscopy.

Results

In this work, we show that a unique glycoside of genistein, ITB-301, inhibits the proliferation of SKOv3 ovarian cancer cells. We found that the 50% growth inhibitory concentration of ITB-301 in SKOv3 cells was 0.5 μM. Similar results were obtained in breast cancer, ovarian cancer, and acute myelogenous leukemia cell lines. ITB-301 induced significant time- and dose-dependent microtubule depolymerization. This depolymerization resulted in mitotic arrest and inhibited proliferation in all ovarian cancer cell lines examined including SKOv3, ES2, HeyA8, and HeyA8-MDR cells. The cytotoxic effect of ITB-301 was dependent on its induction of mitotic arrest as siRNA-mediated depletion of BUBR1 significantly reduced the cytotoxic effects of ITB-301, even at a concentration of 10 μM. Importantly, efflux-mediated drug resistance did not alter the cytotoxic effect of ITB-301 in two independent cancer cell models of drug resistance.

Conclusion

These results identify ITB-301 as a novel anti-tubulin agent that could be used in cancers that are multidrug resistant. We propose a structural model for the binding of ITB-301 to α- and β-tubulin dimers on the basis of molecular docking simulations. This model provides a rationale for future work aimed at designing of more potent analogs.

Electronic supplementary material

The online version of this article (doi:10.1007/s00280-011-1575-2) contains supplementary material, which is available to authorized users.

Inhibitory effects of genistein on metastasis of human hepatocellular carcinoma

AIM: To investigate the inhibitory effects of genistein on metastasis of MHCC97-H hepatocellular carcinoma cells and to explore the underlying mechanism.

METHODS: MHCC97-H hepatocellular carcinoma cells were exposed to genistein. A cell attachment assay was carried out in a microculture well pre-coated with fibronectin. The invasive activity of tumor cells was assayed in a transwell cell culture chamber, and cell cycle and apoptosis were evaluated by a functional assay. In addition, the expression and phosphorylation of FAK were detected by Western blotting. In situ xenograft transplantation of hepatocellular carcinoma was performed in 12 nude mice and lung metastasis of hepatocellular carcinoma was observed.

RESULTS: Genistein significantly inhibited the growth of MHCC97-H cells in vitro. Adhesion and invasiveness of MHCC97-H cells were inhibited in a concentration-dependent fashion, and the inhibitory effect of genistein was more potent in the 10 μg/mL and 20 μg/mL genistein-treated groups. Genistein caused G₀/G₁ cell cycle arrest, an S phase decrease, and increased apoptosis. The expression and phosphorylation of FAK in MHCC-97H cells were significantly decreased. In situ xenograft transplantation of hepatocellular carcinoma was also significantly suppressed by genistein. The number of pulmonary micrometastatic foci in the genistein group was significantly lower compared with the control group (12.3 ± 1.8 vs 16.6 ± 2.6, P < 0.05).

CONCLUSION: Genistein appears to be a promising agent in the inhibition of metastasis of hepatocellular carcinoma.

Trifolium L.--a review on its phytochemical and pharmacological profile

Plants from the genus Trifolium have been used in traditional medicine by many cultures. In Turkish folk medicine, for example, some Trifolium species are used for their expectorant, analgesic, antiseptic properties and also to treat rheumatic aches. Some species are also grown as pasture crops for animals in the Mediterranean. The high quercetin concentration and soyasaponin occurrence make the seeds of some Trifolium species a potential source of health beneficial phytochemicals for use in human nutrition. However, Trifolium pratense has also gained popularity due to research into its use for the treatment for menopausal symptoms. This paper provides an overview of the phytochemical and pharmacological profile of Trifolium species.

Natural isoflavones regulate the quadruplex-duplex competition in human telomeric DNA

Effects of natural isoflavones on the structural competition of human telomeric G-quadruplex d[AG(3)(T(2)AG(3))(3)] and its related Watson-Crick duplex d[AG(3)(T(2)AG(3))(3)-(C(3)TA(2))(3)C(3)T] are investigated by using circular dichroism (CD), ESI-MS, fluorescence quenching measurement, CD stopped-flow kinetic experiment, UV spectroscopy and molecular modeling methods. It is intriguing to find out that isoflavones can stabilize the G-quadruplex structure but destabilize its corresponding Watson-Crick duplex and this discriminated interaction is intensified by molecular crowding environments. Kinetic experiments indicate that the dissociation rate of quadruplex (k(obs290 nm)) is decreased by 40.3% at the daidzin/DNA molar ratio of 1.0 in K(+), whereas in Na(+) the observed rate constant is reduced by about 12.0%. Furthermore, glycosidic daidzin significantly induces a structural transition of the polymorphic G-quadruplex into the antiparallel conformation in K(+). This is the first report on the recognition of isoflavones with conformational polymorphism of G-quadruplex, which suggests that natural isoflavone constituents potentially exhibit distinct regulation on the structural competition of quadruplex versus duplex in human telomeric DNA.

Nucleocytoplasmic-localized acyltransferases catalyze the malonylation of 7-O-glycosidic (iso)flavones in Medicago truncatula

(Iso)flavonoids are commonly accumulated as malonylated or acetylated glycoconjugates in legumes. Sequence analysis on EST database of the model legume Medicago truncatula enabled us to identify nine cDNA sequences encoding BAHD super-family enzymes that are distinct from the most of the characterized anthocyanin/flavonol acyltransferase genes in other species. Functional characterization revealed that three of these corresponding enzymes, MtMaT1, 2 and 3, specifically recognize malonyl CoA as an acyl donor and catalyze the malonylation of a range of isoflavone 7-O-glucosides in vitro. These malonyltransferase genes displayed distinct tissue-specific expression patterns and responded differentially to biotic and abiotic stresses. Consistent with gene expression, the level of the accumulated malonyl isoflavone glucoside was altered in the roots of M. truncatula grown under normal and drought-stressed conditions. Overexpression of the MtMaT1 gene in a previously engineered Arabidopsis line that accumulates genistein glycosides (Proc. Natl Acad. Sci. USA, 99, 2002:14578) led to a malonylated product. Confocal microscopy of the transiently expressed MtMaT1-GFP fusion revealed strong fluorescence in both the cytoplasm and nucleus of M. truncatula and tobacco leaf cells. A truncated MtMaT1 lacking the C-terminal polypeptide of 110 amino acid residues that include the DFGWG motif, the single conserved sequence signature of BAHD super-family members, retained considerable catalytic efficiency, but showed an altered optimum pH preference for maximum activity. Such C-terminal polypeptide deletion or deletion of the DFGWG motif alone led to improper folding of the transiently expressed GFP fusion protein in living cells, and impaired nuclear localization of the enzyme.

Effect of genistein-magnetic-nanoparticles on the growth and apoptosis of gastric cancer cell line SGC-7901

AIM: To observe the effects of different concentrations of genistein-magnetic-nanoparticles (GEN-M-NPs) on the growth and apoptosis of gastric cancer cell line SGC-7901.

METHODS: GEN-M-NPs were prepared by chemical co-precipitation. Morphology of GEN-M-NPs was observed under a transmission electron microscope. Encapsulating efficiency of genistein was determined by high-performance liquid chromatography. After SGC-7901 cells were treated with various concentrations of GEN-M-NPs and genistein, their anti-tumor effects were determined by methyl thiazolyl tetrazolium (MTT) assay. Apoptosis rate was quantified by flow cytometry and DNA fragmentation was evaluated by agarose gel electrophoresis.

RESULTS: GEN-M-NPs were round or elliptical in shape with a diameter of about 105 nm. Their encapsulating efficiency was about 10.3%. The proliferation of SGC-7901 cells in vitro was significantly inhibited by GEN-M-NPs in a time- and dose-dependent manner (P < 0.05). The release of GEN-M-NPs was slower than that of genistein (86.04% vs 67.11%, P < 0.05). After treatment with various concentrations of GEN-M-NPs for 72 h, the apoptosis rate for GEN-M-NPs and negative control groups was 5.62% ± 2.04% (10 μmol/L), 13.46% ± 2.02% (20 μmol/L), 26.40% ± 3.84% (40 μmol/L), 37.34% ± 4.68%(80 μmol/L), 49.43% ± 8.29% (100 μmol/L), and 2.60% ± 1.34% (control), respectively. Agarose gel electrophoresis showed typical apoptotic DNA ladders 24 h after treatment with 40 μmol/L GEN-M-NPs.

CONCLUSION: GEN-M-NPs can effectively inhibit the growth and apoptosis of SGC-7901 cells.

The enhancement of isoflavones water solubility by complexation with modified cyclodextrins: a spectroscopic investigation with implications in the pharmaceutical analysis

The improvement of isoflavones bioavailability by complexation with chemically modified cyclodextrins (CyDs) has been exploited to analyse the drug/macrocycle binding affinity by a conventional method with new useful measures. Genistein (Gen) and daidzein (Daidz) were investigated in aqueous medium and in presence an amount of (2-hydroxypropyl)-beta-cyclodextrin (HP-beta-CyD) at different host/guest molar ratios. The solubility in pure water, approximately 3 x 10(-6)M for Gen and approximately 10 x 10(-6)M for Daidz, was obtained by distributing the of guest molecule between water and the organic solvent. The stoichiometric ratios and stability constants describing the extent of formation of the complexes have been determined by phase-solubility UV-vis measurements and confirmed by circular dichroism data. These results have implications in the determination of the carrier's capacity for the complexation of the drug in water solution.