α-Mangostin, A Novel Dietary Xanthone, Suppresses TPA-Mediated MMP-2 and MMP-9 Expressions through the ERK Signaling Pathway in MCF-7 Human Breast Adenocarcinoma Cells

γ-Mangosteen, an autophagy enhancer, prevents skin-aging via activating KEAP1/NRF2 signaling and downregulating MAPKs/AP-1/NF-κB-mediated MMPs

BACKGROUND

Mangosteens, a naturally occurring xanthones, found abundantly in mangosteen fruits. The anti-skin aging potential of γ-mangosteen (GM) remains unexplored; therefore, we investigated the UVB-induced anti-skin aging of GM via activation of autophagy.

HYPOTHESIS

We hypothesized that GM exerts antioxidant and anti-aging capabilities both in vitro and in vivo through activation of autophagy as well as control of KEAP1/NRF2 signaling and MAPKs/AP-1/NF-κB-mediated MMPs pathways.

METHODS

The anti-skin aging effects of GM were studied using HDF cells and a mice model. Various assays, such as DPPH, ABTS, CUPRAC, FRAP, and ROS generation, assessed antioxidant activities. Kits measured antioxidant enzymes, SA-β-gal staining, collagen, MDA content, si-RNA experiments, and promoter assays. Western blotting evaluated protein levels of c-Jun, c-Fos, p-IκBα/β, p-NF-κB, MAPK, MMPs, collagenase, elastin, KEAP1, NRF2, HO-1, and autophagy-related proteins.

RESULTS

GM exhibited strong antioxidant, collagenase and elastase enzyme inhibition activity surpassing α- and β-mangosteen. GM competitively inhibited elastase with a Ki value of 29.04 µM. GM orchestrated the KEAP1-NRF2 pathway, enhancing HO-1 expression, and suppressed UVB-induced ROS in HDF cells. NRF2 knockdown compromised GM's antioxidant efficacy, leading to uncontrolled ROS post-UVB. GM bolstered endogenous antioxidants, curbing lipid peroxidation in UVB-exposed HDF cells and BALB/c mice. GM effectively halted UVB-induced cell senescence, and reduced MMP-1/-9, while elevated TIMP-1 levels, augmented COL1A1, ELN, and HAS-2 expression in vitro and in vivo. Additionally, it suppressed UVB-induced MAPKs, AP-1, NF-κB phosphorylation. Pharmacological inhibitors synergistically enhanced GM's anti-skin aging potential. Moreover, GM inhibited UVB-induced mTOR activation, upregulated LC3-II, Atg5, Beclin 1, and reduced p62 in both UVB induced HDF cells and BALB/c mice, while blocking of autophagy successfully halt the GM effects against the UVB-induced increase of cell senescence, degradation of collagen through upregulation of MMP-1, underscoring GM's substantial anti-skin aging impact via autophagy induction in vitro and in vivo.

CONCLUSION

Together, GM has potent antioxidant and anti-skin aging ingredients that can be used to formulate skin care products for both the nutraceutical and cosmeceutical industries.

Chitosan/Alginate Polymeric Nanoparticle-Loaded α-Mangostin: Characterization, Cytotoxicity, and In Vivo Evaluation against Breast Cancer Cells

α-mangostin (Amg), a compound isolated from the mangosteen rind (Garcinia mangostana, L.), has demonstrated promising anticancer activity. However, its low solubility and selectivity against cancer cells limit its efficacy. To address this issue, researchers have developed chitosan/alginate polymeric nanoparticles (NANO-AMCAL) to enhance the effectiveness of Amg. In vitro studies have demonstrated that NANO-AMCAL is highly active against breast cancer cells. Therefore, an in vivo study was conducted to evaluate the efficacy of NANO-AMCAL in treating breast cancer in Wistar rats (Rattus norvegicus) and determine the effective dose. The rats were divided into seven treatment groups, including positive control, negative control, pure Amg, and NANO-AMCAL 5 mg, 10 mg, and 20 mg. The rats were injected subcutaneously with a carcinogenic agent, 7,12-dimethylbenz(a)anthracene (DMBA) and were evaluated for weight and tumor volume every three days during treatment. Surgery was performed on day 14, and histopathological studies were carried out on breast and lung cancer tissues. The results showed that NANO-AMCAL significantly enhanced the anticancer activity of Amg in treating breast cancer in Wistar rats. NANO-AMCAL containing 0.33 mg of Amg had a healing effect three times better than 20 mg pure Amg and was comparable to tamoxifen. The effective dose of NANO-AMCAL for anti-breast cancer treatment in Wistar rats was found to be 20 mg, which exhibited a good healing response, and the tumor volume continued to decrease up to 17.43% on the 14th day. Furthermore, histopathological tests showed tissue repair and no metastases. These findings suggest that NANO-AMCAL may be a promising therapeutic option for breast cancer treatment.

Biochemical features and therapeutic potential of α-Mangostin: Mechanism of action, medicinal values, and health benefits

α-Mangostin (α-MG) is a natural xanthone obtained from the pericarps of mangosteen. It exhibits excellent potential, including anti-cancer, neuroprotective, antimicrobial, antioxidant, and anti-inflammatory properties, and induces apoptosis. α-MG controls cell proliferation by modulating signaling molecules, thus implicated in cancer therapy. It possesses incredible pharmacological features and modulates crucial cellular and molecular factors. Due to its lesser water solubility and pitiable target selectivity, α-MG has limited clinical application. As a known antioxidant, α-MG has gained significant attention from the scientific community, increasing interest in extensive technical and biomedical applications. Nanoparticle-based drug delivery systems were designed to improve the pharmacological features and efficiency of α-MG. This review is focused on recent developments on the therapeutic potential of α-MG in managing cancer and neurological diseases, with a special focus on its mechanism of action. In addition, we highlighted biochemical and pharmacological features, metabolism, functions, anti-inflammatory, antioxidant effects and pre-clinical applications of α-MG.

Mangosteen for malignancy prevention and intervention: Current evidence, molecular mechanisms, and future perspectives

Mangosteen (Garcinia mangostana L.), also known as the "queen of fruits", is a tropical fruit of the Clusiacea family. While native to Southeast Asian countries, such as Thailand, Indonesia, Malaysia, Myanmar, Sri Lanka, India, and the Philippines, the fruit has gained popularity in the United States due to its health-promoting attributes. In traditional medicine, mangosteen has been used to treat a variety of illnesses, ranging from dysentery to wound healing. Mangosteen has been shown to exhibit numerous biological and pharmacological activities, such as antioxidant, anti-inflammatory, antibacterial, antifungal, antimalarial, antidiabetic, and anticancer properties. Disease-preventative and therapeutic properties of mangosteen have been ascribed to secondary metabolites called xanthones, present in several parts of the tree, including the pericarp, fruit rind, peel, stem bark, root bark, and leaf. Of the 68 mangosteen xanthones identified so far, the most widely-studied are α-mangostin and γ-mangostin. Emerging studies have found that mangosteen constituents and phytochemicals exert encouraging antineoplastic effects against a myriad of human malignancies. While there are a growing number of individual research papers on the anticancer properties of mangosteen, a complete and critical evaluation of published experimental findings has not been accomplished. Accordingly, the objective of this work is to present an in-depth analysis of the cancer preventive and anticancer potential of mangosteen constituents, with a special emphasis on the associated cellular and molecular mechanisms. Moreover, the bioavailability, pharmacokinetics, and safety of mangosteen-derived agents together with current challenges and future research avenues are also discussed.

Different Modes of Mechanism of Gamma-Mangostin and Alpha-Mangostin to Inhibit Cell Migration of Triple-Negative Breast Cancer Cells Concerning CXCR4 Downregulation and ROS Generation

Background

Two mangostin compounds, gamma-mangostin and alpha-mangostin, show anticancer properties through the inhibition of cell proliferation and cell migration. Metastatic triple-negative breast cancer (TNBC) cells, including MDA-MB-231, highly express C-X-C chemokine receptor type 4 (CXCR4) to maintain reactive oxygen species (ROS) and cell migration.

Objectives

This study was performed to analyze and compare different modes of action of γ-mangostin and α-mangostin as antimigratory effects targeted on CXCR4 in MDA-MB-231 as a model of TNBC cell.

Methods

This study investigated the effect of γ-mangostin and α-mangostin using a series of assays, including Cell Counting Kit-8 (CCK-8) assay for cytotoxicity, wound healing assay for migration study, quantitative real-time polymerase chain reaction (qRT-PCR) for gene expression analysis, and flow cytometry for ROS measurement, along with in silico study to observe the binding between the compound and CXCR4.

Results

The findings revealed half maximal inhibitory concentration (IC50) values of 25 and 20 μM for γ-mangostin and α-mangostin in MDA-MB 231 cells, respectively. Moreover, a concentration of 10 μM was used for the migration assay. Both γ-mangostin and α-mangostin significantly suppressed cell migration within 24 hours. The present gene expression studies revealed the downregulation of key migration-associated genes, namely Farp, CXCR4, and LPHN2, upon γ-mangostin treatment but not α-mangostin. Additionally, both γ-mangostin and α-mangostin increased cellular ROS generation, highlighting the same effect of γ-mangostin and α-mangostin ROS elevation to inhibit cancer cell migration. Molecular docking simulations further suggested a potential interaction between γ-mangostin and α-mangostin with CXCR4 in high affinity.

Conclusions

These findings suggest that both γ-mangostin and α-mangostin inhibit breast cancer cell migration and induce cellular ROS levels in MDA-MB-231 cells; notably, γ-mangostin suppresses CXCR4 mRNA expression that might correlate to its activity to inhibit MDA-MB-231 cell migration.

A Review of Herbal Medicine-Based Phytochemical of Garcinia as Molecular Therapy for Breast Cancer

Data from globocan statistic in 2020 indicate that breast cancer has become highest incidence rate of cancer. Estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) are known immunohistochemistry (IHC) markers that mediate cell growth and survival signaling. Furthermore, regulator proteins, receptors, and their downstream signaling pathways have emerged as critical components in breast cancer formation and proliferation, and have become well-established therapeutic targets and the core focus of breast cancer therapy research. Garcinia is a big genus in the Clusiaceae family that contains a wide spectrum of biologically active metabolites for the chemical composition of their isolated fruits, stem barks, seeds, leaves, and roots, have resulted including polyisoprenylated benzophenones, polyphenols, bioflavonoids, xanthones, lactones, and triterpenes. This review article aimed to analyze the potential of Garcinia phytochemicals as a molecular therapy of breast cancer. The results showed that phytochemicals of Garcinia (i.e., α-mangostin, Cambogin, Gambogic Acid [GA], Garcinol, Griffipavixanthone, Friedolanostane triterpenoid, Hexane, Neobractatin, 7-Epiclusianone, xanthochymol - guttiferone E, and isoxanthochymol - cycloxanthochymol) have anticancer properties, including apoptosis, inhibition of proliferation, and metastasis. This review is important to provide information regarding phytochemicals of Garcinia as an alternative treatment for breast cancer patients. This article selected 28 article researches based on inclusion criteria with the keyword “Garcinia” and “Breast cancer”, in English, and available in full text and abstract searching on PubMed.

Inhibition of cell invasion and migration by targeting matrix metalloproteinase-9 expression via sirtuin 6 silencing in human breast cancer cells

Sirtuin 6 (SIRT6) regulation is involved in carcinogenesis. However, its role in breast cancer (BC) metastasis remains unclear. We investigated the effects of SIRT6 on protein kinase C activator- and cytokine-mediated cancer cell invasion and migration in MCF-7 and MDA-MB-231 cells and the association between SIRT6 and matrix metalloproteinase-9 (MMP-9) expression. To assess MMP-9 and SIRT6 expression in patients, protein levels in BC tissues were analyzed. MCF-7 and MDA-MB-231 cell viability was analyzed using MTT assays. SIRT6 was silenced in both cell lines and protein secretion, expression, and mRNA levels were analyzed. Transcription factor DNA activity was investigated using luciferase assays. Matrigel invasion assays were used to assess the effects of SIRT6 in both cell lines. SIRT6 and MMP-9 expression in cancer tissues was significantly higher than in paired normal breast tissues. 12-O-tetradecanoylphorbol-13-acetate (TPA) or tumor necrosis factor-α (TNF-α) increased MMP-9 expression and cell invasion and migration, but SIRT6 knockdown abolished these effects. SIRT6 overexpression additively increased TPA- and TNF-α-induced MMP-9 expression. SIRT6 knockdown suppressed the mitogen-activated protein kinase (MAPK) signaling pathway and thus TPA- and TNF-α-induced MMP-9 expression. SIRT6 silencing suppressed TPA- and TNF-α-induced nuclear factor-κB (NF-κB) and activator protein-1 (AP-1) expressions in both cell lines, and treatment with MAPK, NF-κB, and AP-1 inhibitors reduced MMP-9 expression. The anti-invasive effects of SIRT6 in BC cells might be mediated by suppression of MAPK phosphorylation and reduction in NF-κB and AP-1 DNA activities, leading to MMP-9 downregulation, suggesting that SIRT6 modulation has the potential to target BC metastasis.

The purple mangosteen (Garcinia mangostana): Defining the anticancer potential of selected xanthones

The purple mangosteen (Garcinia mangostana) is a popular Southeast Asian fruit that has been used traditionally for its health promoting benefits for years. Unique to the mangosteen are a class of phytochemicals known as xanthones that have been reported to display significant anti-cancer and anti-tumor activities, specifically through the promotion of apoptosis, targeting of specific cancer-related proteins, or modulation of cell signaling pathways. α-Mangostin, the most abundant xanthone isolated from the mangosteen, has received substantial attention as it has proven to be a potent phytochemical, specifically as an anticancer agent, in numerous different cancer cell studies and cancer animal models. While the mechanisms for these anticancer effects have been reported in many studies, lesser xanthones, including gartanin, β-mangostin, γ-mangostin, garcinone C, and garcinone E, and mangosteen extracts from the pericarp, roots, rind, and stem show promise for their anticancer activity but their mechanisms of action are not as well developed and remain to be determined. Mangosteen products appear safe and have been well tolerated in human clinical trials where they show antioxidant activity, though their clinical anticancer activity has not yet been evaluated. This review summarizes the work that has been done to explore and explain the anticancer and antitumor activities of α-mangostin, lesser xanthones, and mangosteen extracts in vitro, in vivo, and in humans in various cancers.

Alpha-mangostin dephosphorylates ERM to induce adhesion and decrease surface stiffness in KG-1 cells

Surface stiffness is a unique indicator of various cellular states and events and needs to be tightly controlled. α-Mangostin, a natural compound with numerous bioactivities, reduces the mechanical stiffness of various cells; however, the mechanism by which it affects the actin cytoskeleton remains unclear. We aimed to elucidate the mechanism underlying α-mangostin activity on the surface stiffness of leukocytes. We treated spherical non-adherent myelomonocytic KG-1 cells with α-mangostin; it clearly reduced their surface stiffness and disrupted their microvilli. The α-mangostin-induced reduction in surface stiffness was inhibited by calyculin A, a protein phosphatase inhibitor. α-Mangostin also induced KG-1 cell adhesion to a fibronectin-coated surface. In KG-1 cells, a decrease in surface stiffness and the induction of cell adhesion are largely attributed to the dephosphorylation of ezrin/radixin/moesin proteins (ERMs); α-mangostin reduced the levels of phosphorylated ERMs. It further increased protein kinase C (PKC) activity. α-Mangostin-induced KG-1 cell adhesion and cell surface softness were inhibited by the PKC inhibitor GF109203X. The results of the present study suggest that α-mangostin decreases stiffness and induces adhesion of KG-1 cells via PKC activation and ERM dephosphorylation.

Evaluation of anti-epithelial-mesenchymal transition property of Garcinia mangostana rind extract

Background

Epithelial-mesenchymal transition (EMT) helps solid tumors to lose their intercellular adhesive property and drives metastasis. As mangosteen fruit is known for many beneficial effects including antimicrobial, antioxidant, and anti-tumorigenic properties and has been used widely in traditional medicine, we interrogated its possible anti-metastatic effect on MCF-7 breast cancer cells.

Results

We found that aqueous mangosteen rind extract (MRE) inhibited growth of MCF-7 and altered the transcript levels of ERα, ERβ, and EGFR genes. Additionally, the MRE changed the expression of important markers of EMT, E-Cadherin, N-Cadherin, Snail, and MMP-9. Moreover, MRE inhibited migration of MCF-7 cells.

Conclusion

The results suggest that MRE suppresses growth and inhibits epithelial-mesenchymal transition in MCF-7 cells.

α-Mangostin Induces Apoptosis and Inhibits Metastasis of Breast Cancer Cells via Regulating RXRα-AKT Signaling Pathway

Mangostin, which has the function of anti-inflammatory, antioxidant, and anticancer, etc, is one of the main active ingredients of the hull of the mangosteen. The main objective of the study was to elucidate its anti-cancer function and possible mechanism. α-Mangostin was separated and structurally confirmed. MTT method was used to check the effect of mangostin on breast cancer cell proliferation. Then the effect of α-Mangostin on the transcriptional activity of RXRα was tested by dual-luciferase reporter gene assay. And Western blot (WB) was used to detect the expression of apoptosis-related proteins or cell cycle-associated proteins after treatment. Also, this study was to observe the effects of α-Mangostin on the invasion of breast cancer cell line MDA-MB-231. α-Mangostin regulates the downstream effectors of the PI3K/AKT signaling pathway by degrading RXRα/tRXRα. α-Mangostin can trigger PARP cleavage and induce apoptosis, which may be related to the induction of upregulated BAX expression and downregulation of BAD and cleaved caspase-3 expression in MDA-MB-231 cells through blockade of AKT signaling. The experiments verify that α-Mangostin have evident inhibition effects of invasion and metastasis of MDA-MB-231 cells. Cyclin D1 was involved in the anticancer effects of α-Mangostin on the cell cycle in MDA-MB-231 cells. α-Mangostin induces apoptosis, suppresses the migration and invasion of breast cancer cells through the PI3K/AKT signaling pathway by targeting RXRα, and cyclin D1 has involved in this process.

α-Mangostin Nanoparticles Cytotoxicity and Cell Death Modalities in Breast Cancer Cell Lines

α-Mangostin (AMG) is a potent anticancer xanthone that was discovered in mangosteen (Garcinia mangostana Linn.). AMG possesses the highest opportunity for chemopreventive and chemotherapeutic therapy. AMG inhibits every step in the process of carcinogenesis. AMG suppressed multiple breast cancer (BC) cell proliferation and apoptosis by decreasing the creation of cancerous compounds. Accumulating BC abnormalities and their associated molecular signaling pathways promotes novel treatment strategies. Chemotherapy is a commonly used treatment; due to the possibility of unpleasant side effects and multidrug resistance, there has been substantial progress in searching for alternative solutions, including the use of plant-derived natural chemicals. Due to the limitations of conventional cancer therapy, nanotechnology provides hope for effective and efficient cancer diagnosis and treatment. Nanotechnology enables the delivery of nanoparticles and increased solubility of drugs and drug targeting, resulting in increased cytotoxicity and cell death during BC treatment. This review summarizes the progress and development of AMG’s cytotoxicity and the mechanism of death BC cells. The combination of natural medicine and nanotechnology into a synergistic capital will provide various benefits. This information will aid in the development of AMG nanoparticle preparations and may open up new avenues for discovering an effective BC treatment.

The diverse bioactivity of α-mangostin and its therapeutic implications

α-Mangostin is a xanthone natural product isolated as a secondary metabolite from the mangosteen tree. It has attracted a great deal of attention due to its wide-ranging effects on certain biological activity, such as apoptosis, tumorigenesis, proliferation, metastasis, inflammation, oxidation, bacterial growth and metabolism. This review focuses on the key pathways directly affected by α-mangostin and how this varies between disease states. Insight is also provided, where investigated, into the key structural features of α-mangostin that produce these biological effects. The review then sheds light on the utility of α-mangostin as a investigational tool for certain diseases and demonstrate how future derivatives may increase selectivity and potency for specific disease states.

α-Mangostin Synergizes the Antineoplastic Effects of 5-Fluorouracil Allowing a Significant Dose Reduction in Breast Cancer Cells

Breast cancer is the most common neoplasm and the leading cause of cancer death in women worldwide. Although 5-fluorouracil is a conventional chemotherapeutic agent for breast cancer treatment, its use may result in severe side effects. Thus, there is widespread interest in lowering 5-fluorouracil drawbacks, without affecting its therapeutic efficacy by the concomitant use with natural products. Herein, we aimed at evaluating whether α-mangostin, a natural antineoplastic compound, could increase the anticancer effect of 5-fluorouracil in different breast cancer cell lines, allowing for dose reduction. Cell proliferation was evaluated by sulforhodamine-B assays, inhibitory concentrations and potency were calculated by dose-response curves, followed by analysis of their pharmacological interaction by the combination-index method and dose-reduction index. Cell cycle distribution was evaluated by flow cytometry. Each compound inhibited cell proliferation in a dose-dependent manner, the triple negative breast cancer cells being the most sensitive. When 5-fluorouracil and α-mangostin were used concomitantly, synergistic antiproliferative effect was observed. The calculated dose-reduction index suggested that this combination exhibits therapeutic potential for reducing 5-fluorouracil dosage in breast cancer. Mechanistically, the cotreatment induced cell death in a greater extent than each drug alone. Therefore, α-mangostin could be used as a potent co-adjuvant for 5-fluorouracil in breast cancer.

Investigating the ameliorative effect of alpha-mangostin on development and existing pain in a rat model of neuropathic pain

Mangosteen fruit has been used for various disorders, including pain. The effects of alpha-mangostin, the main component of mangosteen, on the neuropathic pain caused by chronic constriction injury (CCI) were evaluated in rats. In treatment groups, alpha-mangostin (10, 50, 100 mg/kg/day, i.p.) was administered from Day 0, the day of surgery, for 14 days. The degree of heat hyperalgesia, cold, and mechanical allodynia was assessed on Days 0, 3, 5, 7, 10, and 14. The lumbar spinal cord levels of MDA, GSH, inflammatory markers (TLR-4, TNF-α, MMP2, COX2, IL-1β, iNOS, and NO), apoptotic markers (Bcl-2, Bax, and caspase-3) were measured by western blot on Days 7 and 14. Rats in the CCI group showed thermal hyperalgesia, cold, and mechanical allodynia on Days 3-14. All concentrations of alpha-mangostin alleviated CCI-induced behavioral alterations. MDA level augmented and GSH level decreased in the CCI group and alpha-mangostin (50, 100 mg/kg) reversed the alterations. An enhancement in the levels of all inflammatory markers, Bax, and caspase-3 was shown on Days 7 and 14, which was controlled by alpha-mangostin (50 mg/kg). The detected antinociceptive effects of alpha-mangostin may be mediated through antioxidant, anti-inflammatory, and antiapoptotic properties.

β-Mangostin inhibits the metastatic power of cervical cancer cells attributing to suppression of JNK2/AP-1/Snail cascade

β-Mangostin is a natural mangostin with potent anticancer activity against various cancers. In this study, we further explored the anticancer activity of β-mangostin on cervical cancer cells. β-Mangostin did not affect cell viability and cell cycle distribution in HeLa and SiHa cells; however, it dose-dependently inhibited the migration and invasion of both the human cervical cancer cell lines. In addition, we observed that β-mangostin suppressed the expression of integrin αV and β3 and the downstream focal adhesion kinase/Src signaling. We also found that Snail was involved in the β-mangostin inhibited cell migration and invasion of HeLa cell. Then, our findings showed that β-mangostin reduced both nuclear translocation and messenger RNA expression of AP-1 and demonstrated that AP-1 could target to the Snail promoter and induce Snail expression. Kinase cascade analysis and reporter assay showed that JNK2 was involved in the inhibition of AP-1/Snail axis by β-mangostin in HeLa cells. These results indicate that β-mangostin can inhibit the mobility and invasiveness of cervical cancer cells, which may attribute to the suppression of both integrin/Src signaling and JNK2-mediated AP-1/Snail axis. This suggests that β-mangostin has potential antimetastatic potential against cervical cancer cells.

Alpha-mangostin reduces mechanical stiffness of various cells

Alpha-mangostin (α-mangostin) has been identified as a naturally occurring compound with potential anticancer properties. It can induce apoptosis and inhibit the growth and metastasis of cancer cells. Moreover, α-mangostin reduces the mechanical stiffness of lung cancer cells. The objective of this study was to determine the effect of α-mangostin on the mechanical stiffness of various cells, as well as cell viability. The following cell types were examined: human fibroblast TIG-1 cells, human cancerous HeLa cells, human embryonic kidney HEK293 cells, mouse macrophage RAW 264.7 cells, and human myeloblasts KG-1 cells. Cells were treated with α-mangostin, and then examined for cell viability, actin cytoskeletal structures, and surface mechanical stiffness using atomic force microscopy. α-Mangostin demonstrated cytotoxicity against TIG-1, HeLa, HEK293, and KG-1 cells, but not against RAW 264.7 cells. The cytotoxic effect of α-mangostin varies according to cell type. On the other hand, α-mangostin reduced the mechanical stiffness of all cell types, including RAW 264.7 cells. Upon treatment with α-mangostin, F-actin was slightly reduced but the actin cytoskeletal structures were little altered in these cells. Thus, reducing mechanical stiffness of animal cells is an inherent effect of α-mangostin. Our results show that α-mangostin is a naturally occurring compound with potential to change the actin cytoskeletal micro-structures and reduce the surface stiffness of various cells.

Xanthones from the Bark of Garcinia xanthochymus and the Mechanism of Induced Apoptosis in Human Hepatocellular Carcinoma HepG2 Cells via the Mitochondrial Pathway

Xanthones are important chemical constituents of Garcinia xanthochymus and varied bioactivities including cytotoxicity. However, their anti-tumor mechanism has remained unknown. Here, we isolated and identified a new xanthone named garciniaxanthone I (1) and five known compounds from the bark of G. xanthochymus. Their structures were elucidated by NMR analysis and HRESIMS. The anti-proliferation activities of all isolated compounds were evaluated on four human tumor cell lines (HepG2, A549, SGC7901, MCF-7). The results demonstrated that the anti-proliferation activity of xanthone was related to the number and location of prenyl groups. We further found that garciniaxanthone I (GXI) could induce HepG2 apoptosis and enhance the expression of cleaved caspase-8, caspase-9, and caspase-3. GXI could also increase Bax level and concurrently reduce the overexpression of Bcl-2, Bcl-XL, Mcl-1, and surviving in HepG2 cells. Moreover, GXI could inhibit cell migration of HepG2 cells by inhibiting the expressions of MMP-7 and MMP-9. In summary, our study suggests that GXI could induce HepG2 apoptosis via the mitochondrial pathway and might become a lead compound for liver cancer treatment.

Influence of New Synthetic Xanthones on the Proliferation and Migration Potential of Cancer Cell Lines In Vitro

BACKGROUND

Natural plant metabolites and their semisynthetic derivatives have been used for years in cancer therapy. Xanthones are oxygenated heterocyclic compounds produced as secondary metabolites by higher plants, fungi or lichens. Xanthone core may serve as a template in the synthesis of many derivatives that have broad biological activities.

OBJECTIVE

This study synthesized a series of 17 new xanthones, and their anticancer potential was also evaluated.

METHODS

The anticancer potential was evaluated in vitro using a highly invasive T24 cancer cell line. Direct cytotoxic effects of the xanthones were established by IC50 estimation based on XTT assay.

RESULTS

5 compounds of the total 17 showed significant cytotoxicity toward the studied cancer cultures and were submitted to further detailed analysis, including studies examining their influence on gelatinase A and B expression, as well as on the cancer cells migration and adhesion to an extracellular matrix. These analyses were carried out on five human tumor cell lines: A2780 (ovarian cancer), A549 (lung cancer), HeLa (cervical cancer), Hep G2 (liver cancer), and T24 (urinary bladder cancer). All the compounds, especially 4, showed promising anticancer activity: they exhibited significant cytotoxicity towards all the evaluated cell lines, including MCF-7 breast cancer, and hindered migration-motility activity of cancer cells demonstrating more potent activity than α-mangostin which served as a reference xanthone.

CONCLUSION

These results suggest that our xanthone derivatives may be further analyzed in order to include them in cancer treatment protocols.

Complete Disaggregation of MCF-7-derived Breast Tumour Spheroids with Very Low Concentrations of α-Mangostin Loaded in CD44 Thioaptamer-tagged Nanoparticles

Background: α-Mangostin (αMG) is a natural substance that exerts a wide range of antitumor effects. Recently, we described that free αMG was able to dissociate multicellular tumour spheroids (MCTSs) generated from breast carcinoma cells and to reduce their cellular viability and motility. Here, αMG was encapsulated into lipidic nanoparticles (NPs), conjugated or not to a CD44 thioaptamer, and the anticancer action evaluated against MCF-7 breast MCTSs. Methods: NPs containing αMG were formulated with a core of polylactic-co-glycolyc acid. Some of them were decorated with a CD44 thioaptamer using as catalysts 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide and N-hydroxysuccinimide. Both size and density of MCF-7-derived MCTSs were monitored during 72 h of treatment with NPs carrying 0.1, 0.5 and 1.0 μg/ml final concentrations of αMG. MCTSs were cultured on Matrigel or gelatine to better simulate the extracellular environment. Results: The NPs without thioaptamer and conveying 0.1 μg/ml αMG caused a significant dissociation of the MCTSs grown in gelatine after 24 h of treatment (p < 0.01). The most significant disaggregation of MCTSs was obtained using NPs carrying 0.5 μg/ml αMG (p < 0.01). A similar dissociating effect was observed when MCTSs were cultured in Matrigel under the same conditions for 48 - 72 h. By contrast, only concentrations over 1.0 μg/ml of free αMG were able to provoke a damage to MCTSs, consisting in a substantial reduction in their size (p < 0.05). Since the MCTS dissociation induced by αMG-loaded NPs occurred only in the presence of Matrigel or gelatine, an impairment of cell contacts to collagen fibres was likely responsible of this effect. Finally, the treatment of MCTSs with αMG-loaded NPs that were conjugated to the CD44 thioaptamer caused a similar decrease in density but a lower expansion of the spheroid, suggesting that a significant number of cells were died or arrested in cycle. Conclusion: Very low concentrations of αMG delivered by lipidic NPs are sufficient to provoke a substantial disaggregation of MCF-7 MCTSs that involves cell-to-collagen contacts. Similarly, the treatment of MCTSs with NPs conjugated to a CD44 thioaptamer leads to MCTS dissociation but through a more damaging action that causes also a reduction in cell number.

Orientin inhibits invasion by suppressing MMP-9 and IL-8 expression via the PKCα/ ERK/AP-1/STAT3-mediated signaling pathways in TPA-treated MCF-7 breast cancer cells

BACKGROUND

Orientin (luteolin 8-C-β-D-glucopyranoside), a glycosyl dietary flavonoid, has therapeutic effects such as anti-inflammation and antiadipogenesis. However, there is little known about the antimigratory and anti-invasive effects of orientin. Thus, we demonstrate the anti-invasive effects of orientin compared with well-known anticancer flavonoid, luteolin and luteolin 8-C-β-fucopyranoside (LU8C-FP).

PURPOSE

We investigated whether orientin would inhibit the migration and invasion of 12-O-tetradecanoyl phorbol-13-acetate (TPA) induced MCF-7 breast cancer cells.

METHODS

We investigated the anti-invasive mechanism of orientin by using wound-healing assay, Matrigel invasion assay, gelatin zymography, qRT-PCR, ELISA, western blotting, nuclear, membrane and cytosolic fractionations, and immunofluorescence staining in MCF-7 cell line.

RESULTS

We demonstrated the antimigratory and anti-invasive effects of orientin in TPA-treated MCF-7 cells. TPA-induced membrane translocation of protein kinase C alpha (PKCα), phosphorylation of extracellular signal regulated kinase (ERK), and nuclear translocations of activator protein-1 (AP-1) and signal transducer and activator of transcription 3 (STAT3) were downregulated by orientin. In addition, orientin also inhibited matrix metalloproteinase-9 (MMP-9) and interleukin-8 (IL-8) expression.

CONCLUSION

Orientin inhibits migratory and invasive responses by suppressing MMP-9 and IL-8 expression through mitigation of TPA-induced PKCα and ERK activation, as well as the nuclear translocation of AP-1 and STAT3. Therefore, orientin prevents tumor invasion and could be applied as a possible therapeutic agent for the treatment of cancer metastasis.

7-Methoxy-luteolin-8-C-β-6-deoxy-xylo-pyranos-3-uloside exactly (mLU8C-PU) isolated from Arthraxon hispidus inhibits migratory and invasive responses mediated via downregulation of MMP-9 and IL-8 expression in MCF-7 breast cancer cells

7-Methoxy-luteolin-8-C-β-6-deoxy-xylo-pyranos-3-uloside (mLU8C-PU) is a glycosylflavone of luteolin isolated from Arthraxon hispidus (Thunb.). Luteolin is known to exert anti-migratory and anti-invasive effects on tumor cells. However, there are no reports on the effects of mLU8C-PU on tumor invasiveness and associated signaling pathways. In this study, we demonstrated the anti-migratory and anti-invasive effects of mLU8C-PU in 12-O-tetradecanoylphorbol-13-acetate (TPA)-treated MCF-7 breast cancer cells. We also investigated the effect of mLU8C-PU on invasion- related signal transducers, including protein kinase Cα (PKCα), c-Jun N terminal kinase (JNK), activator protein-1 (AP-1), and nuclear factor-kappa B (NF-ĸB). TPA-induced membrane translocation of PKCα, phosphorylation of JNK, and the nuclear translocations of AP-1 and NF-κB were downregulated by mLU8C-PU in MCF-7 cells. In addition, mLU8C-PU also inhibited matrix metalloproteinase-9 (MMP-9) and interleukin-8 (IL-8) expression. These results indicate that mLU8C-PU inhibits migratory and invasive responses in MCF-7 breast cancer cells by suppressing MMP-9 and IL-8 expression through mitigating TPA-induced PKCα, JNK activation, and the nuclear translocation of AP-1 and NF-κB. These results suggest that mLU8C-PU may be used as an anti-metastatic agent.

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.

Alpha-mangostin inhibits the migration and invasion of A549 lung cancer cells

Several studies have indicated that α-mangostin exerts anti-metastasis and anti-subsistence effects on several types of cancer cells. Especially, the anti-metastatic effect of α-mangostin on cancer cells is a prospective function in cancer treatment. However, the metastasis process is complicated, and includes migration, invasion, intravasation, and extravasation; thus, the main target of anti-metastatic effect of α-mangostin is not known. In this study, we investigated the effects of α-mangostin on the invasion, subsistence, and migration of lung cancer cells under co-culture conditions with normal cells and regular mono-culture conditions. We found that α-mangostin killed the lung cancer and normal cells in a dose-dependent manner. Furthermore, the alteration in the surface mechanical properties of cells was examined by using atomic force microscopy. Although the α-mangostin concentrations of 5 and 10 µM did not affect the short-term cell viability, they considerably decreased the Young's modulus of lung cancer cells implying a decline in cell surface actin cytoskeletal properties. Additionally, these concentrations of α-mangostin inhibited the migration of lung cancer cells. In co-culture conditions (cancer cells with normal cells), the invasive activities of cancer cells on normal cells were discernibly observed, and was inhibited after treatment with 5 and 10 µM of α-mangostin. Taken together, α-mangostin suppressed the subsistence of lung cancer cells and displayed anti-metastatic activities by inhibiting the migration and invasion, and reducing the actin cytoskeleton of cancer cells. Our findings suggest that α-mangostin could be a potential therapeutic agent for cancer treatment.

Perfluorooctanoic acid stimulates ovarian cancer cell migration, invasion via ERK/NF-κB/MMP-2/-9 pathway

As widely used in consumer products, perfluorooctanoic acid (PFOA) has become a common environmental pollutant, which has been detected in human serum and associated with cancers. Our previous study showed that PFOA is a carcinogen that promotes endometrial cancer cell migration and invasion through activation of ERK/mTOR signaling. Here, we showed that PFOA (≥100 nM) treatment also stimulated A2780 ovarian cancer cell invasion and migration, which correlated with increased matrix metalloproteinases MMP-2/-9 expression, important proteases associated with tumor invasion and migration. Notably, PFOA treatment induced activation of ERK1/2/ NF-κB signaling. Pre-treatment with U0126, an ERK1/2inhibitor；or JSH-23, a NF-kB inhibitor, can reverse the PFOA-induced cell migration and invasion. Consistent with these results, inhibiting ERK1/2 or NF-κB signaling abolished PFOA-induced up-regulation of MMP-2/-9 expression. These results indicate that PFOA can stimulate ovarian cancer cell migration, invasion and MMP-2/-9 expression by up-regulating ERK/NF-κB pathway.

Effects of α-Mangostin on Viability, Growth and Cohesion of Multicellular Spheroids Derived from Human Breast Cancer Cell Lines

Background: α-Mangostin (αMG) is extracted from Garcinia mangostana Linn and exerts antiproliferative activities. Although several researches on αMG were performed using cell monolayers, the in vitro pharmacological effects on 3D cancer models have never been investigated. Aim of the present study was to find new anticancer properties of αMG by evaluating the changes that this compound provokes in multicellular tumour spheroids (MCTSs). Methods: MCTSs were generated from MDA-MB-231 and MCF-7 breast tumour cell lines and then treated with 0.1÷30 μg/ml αMG for 24 and 48 h. MCTS size, density, and cell migration were determined by software elaboration of phase contrast images captured by a digital camera. Cell viability was evaluated by resazurin and acid phosphatase assays, while cell apoptosis was assessed by a fluorescent assay of caspase activity. The distribution of living cells inside MCTSs was shown by live/dead fluorescence staining. Results: A dose-dependent decrease in cell viability was obtained by treating MDA-MB-231 spheroids with αMG for 48 h (IC₅₀ = 0.70-1.25 μg/ml). A significant reduction in spheroid volume, paralleled by its increased compactness, was observed only at concentration of 30 μg/ml, but not with lower doses of αMG. By contrast, αMG in the range of 5-15 μg/ml increased the size of MCTSs due to a parallel reduction in cell aggregation. The same window of concentrations was also able to stimulate cell apoptosis in a dose-dependent manner. Bimodal volumetric effects were also obtained by treating the spheroids generated from the MCF-7 cells with 0.1÷30 μg/ml αMG for 48 h. Finally, doses higher than 5 μg/ml caused a progressive impairment in cell migration from the edge of MDA-MB-231 MCTSs. Conclusion: After exposure at doses of αMG just above IC₅₀, MDA-MB-231 spheroids showed a significant reduction in cell adhesion that did not stimulate cell migration but, on the contrary, blunted cell motility. These findings suggest a novel anticancer feature of αMG that could be taken into consideration to improve conventional drug penetration into the tumour bulk.

β-mangostin suppresses human hepatocellular carcinoma cell invasion through inhibition of MMP-2 and MMP-9 expression and activating the ERK and JNK pathways

β-mangostin is a dietary xanthone that has been reported to have the anticancer properties in some human cancer cell types. However, the antimetastatic effect and molecular mechanism of β-mangostin action in human hepatocellular carcinoma (HCC) cells remain unknown. In this study, we found that β-mangostin did not induce cytotoxicity in human HCC cells (SK-Hep-1, Huh-7 and HA22T/VGH cells). β-mangostin could inhibit migration and invasion of human HCC cells. Meanwhile, β-mangostin significantly decreased the protein activities and expression of matrix metalloproteinase (MMP)-2 and MMP-9 via increasing the activation of MEK1/2, ERK1/2, MEK4 and JNK1/2 signaling pathways. Furthermore, using specific inhibitor for ERK1/2 (PD98059) and JNK1/2 (JNKII) significantly restored the expression of MMP-2/-9 and invasion by β-mangostin treatment in Huh-7 cells. In addition, β-mangostin effectively restored the protein levels and transcription activity of MMP-2 and MMP-9 in siERK or siJNK-transfected Huh-7 cells, concomitantly with promotion on cell migration and invasion. Taken together, these findings are the first to demonstrate the antimetastatic activity of β-mangostin against human HCC cells, which may act as a promising therapeutic agent for the treatment of HCC.

Medicinal properties of mangosteen (Garcinia mangostana L.): A comprehensive update

Garcinia mangostana L. (Clusiaceae) is a tropical tree native to Southeast Asia known as mangosteen which fruits possess a distinctive and pleasant taste that has granted them the epithet of "queen of the fruits". The seeds and pericarps of the fruit have a long history of use in the traditional medicinal practices of the region, and beverages containing mangosteen pulp and pericarps are sold worldwide as nutritional supplements. The main phytochemicals present in the species are isoprenylated xanthones, a class of secondary metabolites with multiple reports of biological effects, such as antioxidant, pro-apoptotic, anti-proliferative, antinociceptive, anti-inflammatory, neuroprotective, hypoglycemic and anti-obesity. The diversity of actions displayed by mangosteen xanthones shows that these compounds target multiple signaling pathways involved in different pathologies, and place them as valuable sources for developing new drugs to treat chronic and degenerative diseases. This review article presents a comprehensive update of the toxicological findings on animal models, and the preclinical anticancer, analgesic, neuroprotective, antidiabetic and hypolipidemic effects of G. mangostana L. extracts and its main isolates. Pharmacokinetics, drug delivery systems and reports on dose-finding human trials are also examined.

Mangiferin positively regulates osteoblast differentiation and suppresses osteoclast differentiation

Mangiferin is a polyphenolic compound present in Salacia reticulata. It has been reported to reduce bone destruction and inhibit osteoclastic differentiation. This study aimed to determine whether mangiferin directly affects osteoblast and osteoclast proliferation and differentiation, and gene expression in MC3T3‑E1 osteoblastic cells and osteoclast‑like cells derived from primary mouse bone marrow macrophage cells. Mangiferin induced significantly greater WST‑1 activity, indicating increased cell proliferation. Mangiferin induced significantly increased alkaline phosphatase staining, indicating greater cell differentiation. Reverse transcription‑polymerase chain reaction (RT‑PCR) demonstrated that mangiferin significantly increased the mRNA level of runt‑related transcription factor 2 (RunX2), but did not affect RunX1 mRNA expression. Mangiferin significantly reduced the formation of tartrate‑resistant acid phosphatase‑positive multinuclear cells. RT‑PCR demonstrated that mangiferin significantly increased the mRNA level of estrogen receptor β (ERβ), but did not affect the expression of other osteoclast‑associated genes. Mangiferin may inhibit osteoclastic bone resorption by suppressing differentiation of osteoclasts and promoting expression of ERβ mRNA in mouse bone marrow macrophage cells. It also has potential to promote osteoblastic bone formation by promoting cell proliferation and inducing cell differentiation in preosteoblast MC3T3‑E1 cells via RunX2. Mangiferin may therefore be useful in improving bone disease outcomes.

An overview of anticancer activity of Garcinia and Hypericum

Cancer is one of the leading causes of death worldwide (approximately 8.2 million cases/year) and, over the next two decades, a 70% increase in new cancer cases is expected. Through analysis of the available drugs between the years of 1930 and 2014, it was found that 48% were either natural products or their derivatives. This proportion increased to 66% when semi-synthetic products were included. The family Clusiaceae Juss. (Malpighiales) includes approximately 1000 species distributed throughout all tropical and temperate regions. The phytochemical profile of this family includes many chemicals with interesting pharmacological activities, including anticancer activities. This study includes an overview of the in vitro and in vivo anticancer activity of secondary metabolites from Garcinia and Hypericum and the mechanisms involved in this activity. Hypericum no longer belong to Clusiaceae family, but was considered in the past by taxonomists, due to similarities with this family. Research in the area has shown that several compounds belonging to different chemical classes exhibit activity in several tumor cell lines in different experimental models. This review shows the significant antineoplasic activity of these compounds, in particular of these two genera and validates the importance of natural products in the search for anticancer drugs.

In Vitro and In Vivo Inhibitory Effects of α-Mangostin on Cholangiocarcinoma Cells and Allografts

We investigated the anti-cholangiocarcinoma effect of α-mangostin from Garcinia mangostana pericarp extract (GM) in a human cholangiocarcinoma (CCA) cell line and a hamster CCA allograft model. In vitro, human CCA cells were treated with GM at various concentrations and for different time periods; then cell-cycle arrest and apoptosis were evaluated using flow cytometry, and metastatic potential with wound healing assays. In vivo, hamster allografts were treated with GM, gemcitabine (positive control) and a placebo (negative control) for 1 month; tumor weight and volume were then determined. Histopathological features and immunostaining (CK19 and PCNA) characteristics were examined by microscopy. The present study found that α-mangostin could: inhibit CCA cell proliferation by inducing apoptosis through the mitochondrial pathway; induce G1 cell-cycle arrest; and inhibit metastasis. Moreover, α-mangostin could inhibit CCA growth, i.e. reduce tumor mass (weight and size) and alter CCA pathology, as evidenced by reduced positive staining for CK19 and PCNA. The present study thus suggested that α-mangostin is a promising anti-CCA compound whose ready availability in tropical countries might indicate use for prevention and treatment of CCA.

Gartanin induces cell cycle arrest and autophagy and suppresses migration involving PI3K/Akt/mTOR and MAPK signalling pathway in human glioma cells

In central nervous system, glioma is the most common primary brain tumour. The diffuse migration and rapid proliferation are main obstacles for successful treatment. Gartanin, a natural xanthone of mangosteen, suppressed proliferation, migration and colony formation in a time- and concentration-dependent manner in T98G glioma cells but not in mouse normal neuronal HT22 cells. Gartanin, at low micromole, led to cell cycle arrest in G1 phase accompanied by inhibited expression level of G1 cell cycle regulatory proteins cyclin D1, while increased expression level of cyclin-dependent kinase inhibitor p27Kip1. In addition, the secretion and activity of matrix metalloproteinases 2/9 (MMP-2/-9) were significantly suppressed in T98G cells treated with gartanin, and it might result from modulating mitogen-activated protein kinases (MAPK) signalling pathway in T98G glioma cells. Moreover, gartanin significantly induced autophagy in T98G cells and increased GFP-LC3 punctate fluorescence accompanied by the increased expression level of Beclin 1 and LC3-II, while suppressed expression level of p62. Gartanin treatment resulted in obvious inhibition of PI3K/Akt/mTOR signalling pathway, which is important in modulating autophagy. Notably, gartanin-mediated anti-viability was significantly abrogated by autophagy inhibitors including 3-methyladenine (3-MA) and chloroquine (CQ). These results indicate that anti-proliferation effect of gartanin in T98G cells is most likely via cell cycle arrest modulated by autophagy, which is regulated by PI3K/Akt/mTOR signalling pathway, while anti-migration effect is most likely via suppression of MMP-2/-9 activity which is involved in MAPK signalling pathway.

Dose-Independent ADME Properties and Tentative Identification of Metabolites of α-Mangostin from Garcinia mangostana in Mice by Automated Microsampling and UPLC-MS/MS Methods

The information about a marker compound's pharmacokinetics in herbal products including the characteristics of absorption, distribution, metabolism, excretion (ADME) is closely related to the efficacy/toxicity. Also dose range and administration route are critical factors to determine the ADME profiles. Since the supply of a sufficient amount of a marker compound in in vivo study is still difficult, pharmacokinetic investigations which overcome the limit of blood collection in mice are desirable. Thus, we have attempted to investigate concurrently the ADME and proposed metabolite identification of α-mangostin, a major constituent of mangosteen, Garcinia mangostana L, in mice with a wide dose range using an in vitro as well as in vivo automated micro-sampling system together. α-mangostin showed dose-proportional pharmacokinetics at intravenous doses of 5–20 mg/kg and oral doses of 10–100 mg/kg. The gastrointestinal absorption of α-mangostin was poor and the distribution of α-mangostin was relatively high in the liver, intestine, kidney, fat, and lung. α-mangostin was extensively metabolized in the liver and intestine. With regards to the formation of metabolites, the glucuronidated, bis-glucuronidated, dehydrogenated, hydrogenated, oxidized, and methylated α-mangostins were tentatively identified. We suggest that these dose-independent pharmacokinetic characteristics of α-mangostin in mice provide an important basis for preclinical applications of α-mangostin as well as mangosteen. In addition, these experimental methods can be applied to evaluate the pharmacokinetics of natural products in mice.

α-Mangostin: a dietary antioxidant derived from the pericarp of Garcinia mangostana L. inhibits pancreatic tumor growth in xenograft mouse model

AIMS

Pancreatic cancer (PC) is the most aggressive malignant disease, ranking as the fourth most leading cause of cancer-related death among men and women in the United States. In this study, we provide evidence of chemotherapeutic effects of α-mangostin, a dietary antioxidant isolated from the pericarp of Garcinia mangostana L. against human PC.

RESULTS

The chemotherapeutic effect of α-mangostin was determined using four human PC cells (PL-45, PANC1, BxPC3, and ASPC1). α-Mangostin resulted in a significant inhibition of PC cells viability without having any effects on normal human pancreatic duct epithelial cells. α-Mangostin showed a dose-dependent increase of apoptosis in PC cells. Also, α-mangostin inhibited the expression levels of pNF-κB/p65Ser552, pStat3Ser727, and pStat3Tyr705. α-Mangostin inhibited DNA binding activity of nuclear factor kappa B (NF-κB) and signal transducer and activator 3 (Stat3). α-Mangostin inhibited the expression levels of matrix metallopeptidase 9 (MMP9), cyclin D1, and gp130; however, increased expression of tissue inhibitor of metalloproteinase 1 (TIMP1) was observed in PC cells. In addition, i.p. administration of α-mangostin (6 mg/kg body weight, 5 days a week) resulted in a significant inhibition of both primary (PL-45) and secondary (ASPC1) human PC cell-derived orthotopic and ectopic xenograft tumors in athymic nude mice. No sign of toxicity was observed in any of the mice administered with α-mangostin. α-Mangostin treatment inhibited the biomarkers of cell proliferation (Ki-67 and proliferating cell nuclear antigen [PCNA]) in the xenograft tumor tissues.

INNOVATION

We present, for the first time, that dietary antioxidant α-mangostin inhibits the growth of PC cells in vitro and in vivo.

CONCLUSION

These results suggest the potential therapeutic efficacy of α-mangostin against human PC.

Alpha-mangostin inhibits intracellular fatty acid synthase and induces apoptosis in breast cancer cells

Background

Fatty acid synthase (FAS) has been proven over-expressed in human breast cancer cells and consequently, has been recognized as a target for breast cancer treatment. Alpha-mangostin, a natural xanthone found in mangosteen pericarp, has a variety of biological activities, including anti-cancer effect. In our previous study, alpha-mangostin had been found both fast-binding and slow-binding inhibitions to FAS in vitro. This study was designed to investigate the activity of alpha-mangostin on intracellular FAS activity in FAS over-expressed human breast cancer cells, and to testify whether the anti-cancer activity of alpha-mangostin may be related to its inhibitory effect on FAS.

Methods

We evaluated the cytotoxicity of alpha-mangostin in human breast cancer MCF-7 and MDA-MB-231 cells. Intracellular FAS activity was measured by a spectrophotometer at 340 nm of NADPH absorption. Cell Counting Kit assay was used to test the cell viability. Immunoblot analysis was performed to detect FAS expression level, intracellular fatty acid accumulation and cell signaling (FAK, ERK1/2 and AKT). Apoptotic effects were detected by flow cytometry and immunoblot analysis of PARP, Bax and Bcl-2. Small interfering RNA was used to down-regulate FAS expression and/or activity.

Results

Alpha-mangostin could effectively suppress FAS expression and inhibit intracellular FAS activity, and result in decrease of intracellular fatty acid accumulation. It could also reduce cell viability, induce apoptosis in human breast cancer cells, increase in the levels of the PARP cleavage product, and attenuate the balance between anti-apoptotic and pro-apoptotic proteins of the Bcl-2 family. Moreover, alpha-mangostin inhibited the phosphorylation of FAK. However, the active forms of AKT, and ERK1/2 proteins were not involved in the changes of FAS expression induced by alpha-mangostin.

Conclusions

Alpha-mangostin induced breast cancer cell apoptosis by inhibiting FAS, which provide a basis for the development of xanthone as an agent for breast cancer therapy.

A high-content assay strategy for the identification and profiling of ABCG2 modulators in live cells

ABCG2 is a member of the ATP-binding cassette (ABC) family of transporters, the overexpression of which has been implicated in resistance to various chemotherapeutic agents. Though a number of cell-based assays to screen for inhibitors have been reported, they do not provide a content-rich platform to discriminate toxic and autofluorescent compounds. To fill this gap, we developed a live high-content cell-based assay to identify inhibitors of ABCG2-mediated transport and, at the same time, assess their cytotoxic effect and potential optical interference. We used a pair of isogenic U87MG human glioblastoma cell lines, with one stably overexpressing the ABCG2 transporter. JC-1 (J-aggregate-forming lipophilic cation 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazol carbocyanine iodide) was selected as the optimal reporter substrate for ABCG2 activity, and the resulting assay was characterized by a Z' value of 0.50 and a signal-to-noise (S/N) ratio of 14 in a pilot screen of ∼ 7,000 diverse chemicals. The screen led to the identification of 64 unique nontoxic positives, yielding an initial hit rate of 1%, with 58 of them being confirmed activity. In addition, treatment with two selected confirmed positives suppressed the side population of U87MG-ABCG2 cells that was able to efflux the Hoechst dye as measured by flow cytometry, confirming that they constitute potent new ABCG2 transporter inhibitors. Our results demonstrate that our live cell and content-rich platform enables the rapid identification and profiling of ABCG2 modulators, and this new strategy opens the door to the discovery of compounds targeting the expression and/or trafficking of ABC transporters as an alternative to functional inhibitors that failed in the clinic.

Biological activities and bioavailability of mangosteen xanthones: a critical review of the current evidence

Mangosteen (Garcinia mangostana L.) is a tropical tree native to Southeast Asia that produces a fruit whose pericarp contains a family of tricyclic isoprenylated polyphenols referred to as xanthones. Numerous in vitro studies have shown that these xanthones possess anti-oxidant, anti-proliferative, pro-apoptotic, anti-inflammatory and anti-carcinogenic activities. Aggressive marketing of such health promoting benefits has resulted in mangosteen’s classification as a “superfruit”. This has led to sales of mangosteen containing beverages in USA alone exceeding $200 million in 2008 despite very limited animal and human studies. This review will (a) critically address recent reports of in vivo studies on the bioavailability and metabolism of mangosteen xanthones, (b) update the in vitro and in vivo data on anti-cancer and anti-inflammatory activities of mangosteen xanthones, and (c) suggest needed areas of inquiry regarding the absorption, metabolism and efficacy of mangosteen xanthones.

Luteolin 8-C-β-fucopyranoside inhibits invasion and suppresses TPA-induced MMP-9 and IL-8 via ERK/AP-1 and ERK/NF-κB signaling in MCF-7 breast cancer cells

Matrix metalloproteinase 9 (MMP-9) and interleukin-8 (IL-8) play major roles in tumor progression and invasion of breast cancer cells. The present study was undertaken to investigate the inhibitory mechanism of cell invasion by luteolin 8-C-β-fucopyranoside (named as LU8C-FP), a C-glycosylflavone, in human breast cancer cells. We investigated whether LU8C-FP would inhibit MMP-9 activation and IL-8 expression in 12-O-tetradecanoylphorbol-13-acetate (TPA)-treated MCF-7 breast cancer cells. LU8C-FP suppressed TPA-induced MMP-9 and IL-8 secretion and mRNA expression via inhibition of the MAPK signaling pathway and down-regulation of nuclear AP-1 and NF-κB. TPA-induced phosphorylation of ERK 1/2 was suppressed by LU8C-FP, whereas JNK and p38 MAPK phosphorylation were unaffected. In addition, LU8C-FP blocked the ERK 1/2 pathways following expression of MMP-9 and IL-8. These results suggest LU8C-FP may function to suppress invasion of breast cancer cells through the ERK/AP-1 and ERK/NF-κB signaling cascades.

A Concise and Efficient Total Synthesis of α-Mangostin and β-Mangostin from Garcinia Mangostana

The concise, efficient synthesis of α-mangostin is described in eight simple steps with 8.3% overall yield. Highlights include a practical approach to construct the isopentene groups and other diverse groups at C–2 and C–8 of the xanthene skeleton through Claisen rearrangement and Wittig reaction. Meanwhile the first total synthesis of β-mangostin is presented with a similar approach.

α-Mangostin: anti-inflammatory activity and metabolism by human cells

Information about the anti-inflammatory activity and metabolism of α-mangostin (α-MG), the most abundant xanthone in mangosteen fruit, in human cells is limited. On the basis of available literature, we hypothesized that α-MG will inhibit the secretion of pro-inflammatory mediators by control and activated macrophage-like THP-1, hepatic HepG2, enterocyte-like Caco-2, and colon HT-29 human cell lines, as well as primary human monocyte-derived macrophages (MDM), and that such activity would be influenced by the extent of metabolism of the xanthone. α-MG attenuated TNF-α and IL-8 secretion by the various cell lines but increased TNF-α output by both quiescent and LPS-treated MDM. The relative amounts of free and phase II metabolites of α-MG and other xanthones present in media 24 h after addition of α-MG was shown to vary by cell type and inflammatory insult. Increased transport of xanthones and their metabolites across Caco-2 cell monolayers suggests enhanced absorption during an inflammatory episode. The anti-inflammatory activities of xanthones and their metabolites in different tissues merit consideration.

α-Mangostin suppresses lipopolysaccharide-induced invasion by inhibiting matrix metalloproteinase-2/9 and increasing E-cadherin expression through extracellular signal-regulated kinase signaling in pancreatic cancer cells

Invasion and metastasis are major factors in the poor prognosis of pancreatic cancer, which remains one of the most aggressive and lethal diseases worldwide. α-mangostin, a major xanthone compound identified in the pericarp of mangosteen (Garcinia mangostana, Linn; GML), possesses unique biological activities, including antioxidant, antitumor and anti-inflammatory effects. Whether α-mangostin is able to inhibit the invasive ability of pancreatic cancer cells has not been elucidated. In the present study, α-mangostin was shown to inhibit the invasive ability of the pancreatic cancer cell lines MIAPaCa-2 and BxPC-3. The results showed that α-mangostin inhibited the growth of the pancreatic cancer cells in a dose- and time-dependent manner. At concentrations of <5 μM, α-mangostin had no significant effects on cytotoxicity, but significantly inhibited the invasion and migration of pancreatic cancer cells and the expression of matrix metalloproteinase (MMP)-2 and MMP-9, while increasing the expression of E-cadherin. The present data also showed that α-mangostin exerted an inhibitory effect on the phosphorylation of extracellular-signal-regulated kinase (ERK). Furthermore, the reduction of ERK phosphorylation by small interfering RNA (siRNA) potentiated the effect of α-mangostin. Taken together, the data suggest that α-mangostin inhibited the invasion and metastasis of pancreatic cancer cells by reducing MMP-2 and MMP-9 expression, increasing E-cadherin expression and suppressing the ERK signaling pathway. The present study suggests that α-mangostin may be a promising agent against pancreatic cancer.

Xanthones from mangosteen extracts as natural chemopreventive agents: potential anticancer drugs

Despite decades of research, the treatment and management of malignant tumors still remain a formidable challenge for public health. New strategies for cancer treatment are being developed, and one of the most promising treatment strategies involves the application of chemopreventive agents. The search for novel and effective cancer chemopreventive agents has led to the identification of various naturally occurring compounds. Xanthones, from the pericarp, whole fruit, heartwood, and leaf of mangosteen (Garcinia mangostana Linn., GML), are known to possess a wide spectrum of pharmacologic properties, including antioxidant, anti- tumor, anti-allergic, anti-inflammatory, anti-bacterial, anti-fungal, and anti-viral activities. The potential chemopreventive and chemotherapeutic activities of xanthones have been demonstrated in different stages of carcinogenesis (initiation, promotion, and progression) and are known to control cell division and growth, apoptosis, inflammation, and metastasis. Multiple lines of evidence from numerous in vitro and in vivo studies have confirmed that xanthones inhibit proliferation of a wide range of human tumor cell types by modulating various targets and signaling transduction pathways. Here we provide a concise and comprehensive review of preclinical data and assess the observed anticancer effects of xanthones, supporting its remarkable potential as an anticancer agent.

Alpha-mangostin suppresses MMP-2 and MMP-9 expression in head and neck squamous carcinoma cells

The purpose of this study was to investigate the effect of alpha-mangostin on matrix metalloproteinase (MMP)-2 and MMP-9 expression in head and neck squamous cell carcinoma (HNSCC). The human HNSCC cell lines were treated with alpha-mangostin and the cytotoxicity of alpha-mangostin in HNSCC was determined using the MTS assay. To determine the effect of alpha-mangostin on the expression of MMP-2 and MMP-9 in HNSCC, gelatin zymography and RT-PCR were performed. The results showed that alpha-mangostin increased in growth inhibition of HNSCC cell lines in a concentration-dependent manner. Treatment with alpha-mangostin decreased MMP-2 and MMP-9 expression in a concentration-dependent manner in all cell lines. These findings suggested that alpha-mangostin might be a potential therapeutic agent for HNSCC.

α-Mangostin induces apoptosis and suppresses differentiation of 3T3-L1 cells via inhibiting fatty acid synthase

α-Mangostin, isolated from the hulls of Garcinia mangostana L., was found to have in vitro cytotoxicity against 3T3-L1 cells as well as inhibiting fatty acid synthase (FAS, EC 2.3.1.85). Our studies showed that the cytotoxicity of α-mangostin with IC₅₀ value of 20 µM was incomplicated in apoptotic events including increase of cell membrane permeability, nuclear chromatin condensation and mitochondrial membrane potential (ΔΨm) loss. This cytotoxicity was accompanied by the reduction of FAS activity in cells and could be rescued by 50 µM or 100 µM exogenous palmitic acids, which suggested that the apoptosis of 3T3-L1 preadipocytes induced by α-mangostin was via inhibition of FAS. Futhermore, α-mangostin could suppress intracellular lipid accumulation in the differentiating adipocytes and stimulated lipolysis in mature adipocytes, which was also related to its inhibition of FAS. In addition, 3T3-L1 preadipocytes were more susceptible to the cytotoxic effect of α-mangostin than mature adipocytes. Further studies showed that α-mangostin inhibited FAS probably by stronger action on the ketoacyl synthase domain and weaker action on the acetyl/malonyl transferase domain. These findings suggested that α-mangostin might be useful for preventing or treating obesity.

HDL of patients with type 2 diabetes mellitus elevates the capability of promoting breast cancer metastasis

PURPOSE

Epidemiologic studies suggested complicated associations between type 2 diabetes mellitus and breast cancer. High-density lipoprotein (HDL) is inversely associated with the risk and mortality of breast cancer. Our study is to determine the different effects of normal and diabetic HDL on breast cancer cell metastasis.

EXPERIMENTAL DESIGN

MDA-MB-231 and MCF7 cells were treated with N-HDL, D-HDL, G-HDL, and Ox-HDL. Cell metastasis potency was examined using a tail-vein injection model, and cell adhesion abilities to human umbilical vein endothelial cells (HUVEC) and extracellular matrix (ECM) were determined in vitro. Integrin expression and protein kinase C (PKC) activity were evaluated, and PKC inhibitor was applied.

RESULTS

D-HDL dramatically promoted cell pulmonary metastasis (103.6% increase at P < 0.001 for MDA-MB-231 with 1 × 10(5) cell injection; 157.1% increase at P < 0.05 for MCF7 with 4 × 10(5) cell injection) and hepatic metastasis (18.1-fold increase at P < 0.001 for MCF7 with 4 × 10(5) cell injection), and stimulated higher TC-HUVECs adhesion (21.9% increase at P < 0.001 for MDA-MB-231; 23.6% increase at P < 0.05 for MCF7) and TC-ECM attachment (59.9% and 47.9% increase, respectively, for MDA-MB-231 and MCF7, both at P < 0.01) compared with N-HDL. D-HDL stimulated higher integrin (β1, β2, β3, and αν) expression on cell surface and induced higher PKC activity. Increased TC-HUVECs and TC-ECM adhesion induced by D-HDL, G-HDL, and Ox-HDL could be inhibited by staurosporine.

CONCLUSIONS

Our study showed that glycation and oxidation of HDL in diabetic patients could lead to abnormal actions on breast cancer cell adhesion to HUVECs and ECM, thereby promoting metastasis progression of breast cancer. This will largely draw the attention of HDL-based treatments in the diabetes patients with breast cancer.

α-Mangostin extracted from the pericarp of the mangosteen (Garcinia mangostana Linn) reduces tumor growth and lymph node metastasis in an immunocompetent xenograft model of metastatic mammary cancer carrying a p53 mutation

BACKGROUND

The mangosteen fruit has a long history of medicinal use in Chinese and Ayurvedic medicine. Recently, the compound α-mangostin, which is isolated from the pericarp of the fruit, was shown to induce cell death in various types of cancer cells in in vitro studies. This led us to investigate the antitumor growth and antimetastatic activities of α-mangostin in an immunocompetent xenograft model of mouse metastatic mammary cancer having a p53 mutation that induces a metastatic spectrum similar to that seen in human breast cancers.

METHODS

Mammary tumors, induced by inoculation of BALB/c mice syngeneic with metastatic BJMC3879luc2 cells, were subsequently treated with α-mangostin at 0, 10 and 20 mg/kg/day using mini-osmotic pumps and histopathologically examined. To investigate the mechanisms of antitumor ability by α-mangostin, in vitro studies were also conducted.

RESULTS

Not only were in vivo survival rates significantly higher in the 20 mg/kg/day α-mangostin group versus controls, but both tumor volume and the multiplicity of lymph node metastases were significantly suppressed. Apoptotic levels were significantly increased in the mammary tumors of mice receiving 20 mg/kg/day and were associated with increased expression of active caspase-3 and -9. Other significant effects noted at this dose level were decreased microvessel density and lower numbers of dilated lymphatic vessels containing intraluminal tumor cells in mammary carcinoma tissues. In vitro, α-mangostin induced mitochondria-mediated apoptosis and G1-phase arrest and S-phase suppression in the cell cycle. Since activation by Akt phosphorylation plays a central role in a variety of oncogenic processes, including cell proliferation, anti-apoptotic cell death, angiogenesis and metastasis, we also investigated alterations in Akt phosphorylation induced by α-mangostin treatment both in vitro and in vivo. Quantitative analysis and immunohistochemistry showed that α-mangostin significantly decreased the levels of phospho-Akt-threonine 308 (Thr308), but not serine 473 (Ser473), in both mammary carcinoma cell cultures and mammary carcinoma tissues in vivo.

CONCLUSIONS

Since lymph node involvement is the most important prognostic factor in breast cancer patients, the antimetastatic activity of α-mangostin as detected in mammary cancers carrying a p53 mutation in the present study may have specific clinical applications. In addition, α-mangostin may have chemopreventive benefits and/or prove useful as an adjuvant therapy, or as a complementary alternative medicine in the treatment of breast cancer.

α-Mangostin, a dietary xanthone, induces autophagic cell death by activating the AMP-activated protein kinase pathway in glioblastoma cells

This study is the first to investigate the anticancer effects of α-mangostin in human glioblastoma cells. α-Mangostin decreases cell viability by inducing autophagic cell death but not apoptosis. Pretreatment of cells with the autophagy inhibitors 3-methyladenine (3-MA) and bafilomycin or knockdown beclin-1, resulted in the suppression of α-mangostin-mediated cell death. We also found that liver kinase B1 (LKB1)/AMP-activated protein kinase (AMPK) signaling is a critical mediator of α-mangostin-induced inhibition of cell growth. Activation of AMPK induces α-mangostin-mediated phosphorylation of raptor, which subsequently associates with 14-3-3γ and results in the loss of mTORC1 activity. The phosphorylation of both downstream targets of mTORC1, p70 ribosomal protein S6 kinase (p70S6 kinase) and 4E-BP1, is also diminished by activation of AMPK. Furthermore, the inhibition of AMPK expression with shRNAs or an inhibitor of AMPK reduced α-mangostin-induced autophagy and raptor phosphorylation, supporting the theory that activation of AMPK is beneficial to autophagy. A further investigation revealed that α-mangostin also induced autophagic cell death in transplanted glioblastoma in nude mice. Together, these results suggest a critical role for AMPK activation in the α-mangostin-induced autophagy of human glioblastoma cells.