Mangosenone F, A Furanoxanthone from Garciana mangostana, Induces Reactive Oxygen Species-Mediated Apoptosis in Lung Cancer Cells and Decreases Xenograft Tumor Growth

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.

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.

Implication of Prophetic Variables and their Impulsive Interplay in CA Prostate Patients Experiencing Osteo-Metastasis

AIMS

To identify variables having a critical role in prostate cancer patients experiencing osteometastasis.

BACKGROUND

Prostatic carcinoma is a multifactorial complex disorder that exhibits an increased propensity to develop bone metastasis. An interplay of inflammatory and bone remodeling parameters promotes the formation of pre-metastatic niches in bones of patients, which could render them more vulnerable to skeletal disabilities.

OBJECTIVE

To evaluate the multi-dynamic inter-relationship of circulating variables in prostate cancer patients experiencing osteo-metastasis.

MATERIALS AND METHODS

Fifty-seven (n=57) men with clinically confirmed prostate cancer, fifty-nine (n=59) with skeletal metastases, and one hundred (n=100) healthy subjects i.e., men aging from 53-84 years with no clinical evidence of prostate were recruited from the Jinnah Hospital Lahore, Pakistan. Informed consent was obtained, and a venous blood sample was drawn and stored at -70oC until assayed. Levels of variables were evaluated using appropriate methods. Levels of Matrix Metalloproteinases (MMPs), Osteopontin (OPN), TGH- β, and sRANKL were estimated by the ELISA method. Each sample was suspended and the given protocol was employed. ELISA readings were obtained for the estimation of all variables.

RESULTS

Highly significant (P˂0.05) differential expression of oxidative stress, inflammatory cytokines, and bone remodeling variables were observed in localized and osteo-metastatic CA prostate patients. A strong positive correlation was revealed among OPN, sRANKL, MMP-7, MMP-9, PSA, and TGF-β (OPN vs. MMP-7, r=0.698* and OPN vs. MMP-9, r=0.765**, OPN vs. RANKL, =0.856*, sRANKL vs. MMP-9, r=0.825**, TGF- β vs. RANKL, r=0.868* and PSA vs. TGF- β, r=0.752*); lower levels of OPG were estimated in metastasized patients, showing that both osteolytic and osteoblastic phases of bone remodeling occur simultaneously.

CONCLUSION

The altered oxidative and inflammatory responses endorse Matrix Metalloproteinases (MMPs) increased activity, RANKL/OPG imbalance, and enhanced bone matrix proteins turnover, which can foster the process of osteo-metastasis. The perturbed RANKL/OPG drift and enhanced PSA levels are associated with increased TGF-β activity to aggravate Epithelial Mesenchymal transition (EM) and osteo-tropism of prostate cancer. Thus, designing novel targets of these major variables can minimize the incidence of prostate cancer patients.

Natural Polyphyllins (I, II, D, VI, VII) Reverses Cancer Through Apoptosis, Autophagy, Mitophagy, Inflammation, and Necroptosis

Cancer is the second leading cause of mortality worldwide. Conventional therapies, including surgery, radiation, and chemotherapy, have limited success because of secondary resistance. Therefore, safe, non-resistant, less toxic, and convenient drugs are urgently required. Natural products (NPs), primarily sourced from medicinal plants, are ideal for cancer treatment because of their low toxicity and high success. NPs cure cancer by regulating different pathways, such as PI3K/AKT/mTOR, ER stress, JNK, Wnt, STAT3, MAPKs, NF-kB, MEK-ERK, inflammation, oxidative stress, apoptosis, autophagy, mitophagy, and necroptosis. Among the NPs, steroid saponins, including polyphyllins (I, II, D, VI, and VII), have potent pharmacological, analgesic, and anticancer activities for the induction of cytotoxicity. Recent research has demonstrated that polyphyllins (PPs) possess potent effects against different cancers through apoptosis, autophagy, inflammation, and necroptosis. This review summarizes the available studies on PPs against cancer to provide a basis for future research.

Molecular mechanisms of anticancer activities of polyphyllin VII

Cancer is the leading cause of mortality in the world. The major therapies for cancer treatment are chemotherapy, surgery, and radiation therapy. All these therapies expensive, toxic and show resistance. The plant-derived compounds are considered safe, cost-effective and target cancer through different pathways. In these pathways include oxidative stress, mitochondrial dependent and independent, STAT3, NF-kB, MAPKs, cell cycle, and autophagy pathways. One of the new plants derived compounds is Polyphyllin VII (PPVII), which target cancer through different molecular mechanisms. In literature, there is a review gap of studies on PPVII; therefore in the current review, we summarized the available studies on PPVII to provide a base for future research.

Molecular Mechanisms of Anticancer Activities of Puerarin

Medicinal plants are a vital source of natural products (NPs) that can cure cancer through modulation of different pathways, including oxidative stress, extrinsic and intrinsic apoptosis, cell cycle, inflammation, NF-kB, PI3K/AKT/mTOR, AMPK (JNK), MEK/ERK (Raf)-MEK-ERK and autophagy. Puerarin (Pue), an important NP belonging to the isoflavone glycoside group, is derived from Pueraria lobata (Willd.) Ohwi, Pueraria thomsonii Benth, and Pueraria tuberosa (Willd.). This NP was approved by the Chinese Ministry of Health for the treatment of different diseases in 1993, but it was also later reported to exhibit anticancer activity. Pue causes cancer cells death through modulation of different mechanisms including oxidative stress, intrinsic and extrinsic, Survivin and XIAP, PI3K/AKT/mTOR, Ras-Raf-MEK-ERK, JNK, cell cycle, AMPK, NF-kB, inflammation and autophagy pathways. Therefore, this review compiles for the first time the studies about the anticancer mechanism of Pue and provides comprehensive information about the anticancer effects of Pue. This review may serve as a basis for future research and clinical treatment.

Natural gypenosides: targeting cancer through different molecular pathways

The second foremost cause of mortality around the word is cancer. Conventional therapies, such as radiation, surgery, and chemotherapy have limited accessibility owing to secondary resistance. Therefore, convenient, safe, and nonresistant drugs are urgently needed. Plant-derived natural products have attracted considerable interest owing to their high efficacy, low toxicity, and convenience. Gypenosides (Gyp) inhibit invasion, migration, metastasis, and proliferation and induce apoptosis in different cancers, including oral, lung, colorectal, hepatocellular, and leukemic cancers through different molecular pathways. This review summarizes Gyp studies on cancer to serve as a reference for further research and clinical trials.

Brevilin A promotes oxidative stress and induces mitochondrial apoptosis in U87 glioblastoma cells

Background

Sesquiterpene lactones are plant-derived, natural, bioactive molecules often used against inflammatory diseases in traditional Chinese medicines. Recently, sesquiterpene lactones have been reported to exhibit potent anticancer activity. In the present study, we have investigated the anticancer activity of Brevilin A, a sesquiterpene lactone component of Centipeda minima, against U87 glioblastoma cells.

Materials and methods

The cell proliferation was determined by MTT assay. Cell morphological changes were observed by phase-contrast microscopy. Flow cytometry was used to measure apoptosis. Glutathione (GSH), ROS generation, and mitochondrial membrane potential were measured using commercially available kits. The expression of proteins was measured by Western blotting analysis.

Results

Brevilin A inhibited the proliferation of, and induced severe morphological changes and apoptotic cell death in, U87 glioblastoma cells in a dose-dependent manner. Further mechanistic study revealed that Brevilin A induces oxidative stress, as evident from ROS generation, GSH depletion, and increased phosphorylation of stress-activated proteins p38 and JNK. Furthermore, Brevilin A bcl-xl/bak ratio, decreased mitochondrial membrane potential and induced cytochrome c release from mitochondria into cytosol in a dose-dependent manner. Finally, Brevilin A decreased the expression of Xiap and increased the expression of cleaved forms of caspase-9 and -3 and PARP in a dose-dependent manner.

Conclusion

Collective findings demonstrated that Brevilin A is a potent, anticancer, bioactive molecule and it effectively induces apoptosis in U87 glioblastoma cells, which is associated with induction of oxidative stress and mitochondrial dysfunction.

Santamarine Inhibits NF-κB Activation and Induces Mitochondrial Apoptosis in A549 Lung Adenocarcinoma Cells via Oxidative Stress

Santamarine (STM), a sesquiterpene lactone component of Magnolia grandiflora and Ambrosia confertiflora, has been shown to possess antimicrobial, antifungal, antibacterial, anti-inflammatory, and anticancer activities. However, no study has yet been conducted to investigate the molecular mechanism of STM-mediated anticancer activity. In the present study, we found that STM inhibits growth and induces apoptosis in A549 lung adenocarcinoma cells through induction of oxidative stress. STM induces oxidative stress by promoting reactive oxygen species (ROS) generation, depleting intracellular glutathione (GSH), and inhibiting thioredoxin reductase (TrxR) activity in a dose-dependent manner. Further mechanistic study demonstrated that STM induces apoptosis by modulation of Bax/Bcl-2 expressions, disruption of mitochondrial membrane potential, activation of caspase-3, and cleavage of PARP in a dose-dependent manner. Moreover, STM inhibited the constitutive and inducible translocation of NF-κBp65 into the nucleus. IKK-16 (I-κB kinase inhibitor) augmented the STM-induced apoptosis, indicating that STM induces apoptosis in A549 cells at least in part through NF-κB inhibition. Finally, STM-induced apoptosis and expressions of apoptosis regulators were effectively inhibited by thiol antioxidant N-acetyl-L-cysteine (NAC), indicating that STM exerts its anticancer effects mainly through oxidative stress. To the best of our knowledge, this is the first report providing evidence of anticancer activity and molecular mechanism of STM.

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.

Alantolactone induces apoptosis, promotes STAT3 glutathionylation and enhances chemosensitivity of A549 lung adenocarcinoma cells to doxorubicin via oxidative stress

Alantolactone (ALT), a sesquiterpene lactone component of Inula helenium, has been reported to exert anticancer activity in various cancers. However, the cellular targets and underlying mechanism of anticancer activity of ALT in various cancers including lung cancer has not been fully defined. In the present study, we found that ALT effectively inhibits proliferation and triggers oxidative stress mediated-apoptosis in A549 lung adenocarcinoma cells by inducing ER stress and mitochondrial dysfunction. This ALT-mediated apoptosis was inhibited by NAC while diamide potentiated it. Moreover, ALT effectively suppressed both constitutive and inducible STAT3 activation, inhibited its translocation into nucleus and decreased its DNA binding activity. Further mechanistic study revealed that ALT abrogated STAT3 activation by promoting STAT3 glutathionylation. ROS scavenger NAC reverted ALT-mediated STAT3 glutathionylation and inhibition of STAT3 phosphorylation. Finally, ALT enhanced chemosensitivity of A549 cells to doxorubicin and reversed doxorubicin resistance in A549/DR cells by inhibiting STAT3 activation and P-glycoprotein expression and increasing intracellular accumulation of doxorubicin. Suppression of STAT3 activation by targeting ROS metabolism with ALT thus discloses a previously unrecognized mechanism underlying the biological activity of ALT. Taken together; ALT induces oxidative stress-dependent apoptosis, inhibits STAT3 activation and augments doxorubicin toxicity in A549 lung cancer cells. These findings provide an in-depth insight into the molecular mechanism of ALT in the treatment of lung cancer.

Anticancer effect of SZC015 on lung cancer cells through ROS-dependent apoptosis and autophagy induction mechanisms in vitro

Oleanolic acid (OA) and its several derivatives possess various pharmacological activities, such as antitumor and anti-inflammation. In present study, anticancer effect of SZC015, an OA derivative, and its underlying mechanisms were investigated. We demonstrated that cell viability was significantly decreased in SZC015-treated lung cancer cells, but has less cytotoxicity in human bronchial epithelial cell line. Further investigation verified that apoptosis and autophagy induction and G₀/G₁ phase arrest were observed in SZC015-treated H322 cells. Mechanically, the level of Akt, p-Akt, p-IκBα, and total p65, the p-p65 in the cytoplasm and nucleus were suppressed by SZC015 in H322 cells, respectively. Inhibition of p65 nuclear translocation was also confirmed by immunofluorescence staining. In addition, co-treatment with chloroquine, an autophagy inhibitor, significantly inhibited SZC015-induced autophagy and enhanced SZC015-induced apoptotic cell death. Intracellular ROS was increased in a concentration-dependent manner, which could be prevented by N-Acetyl l-Cysteine, an ROS scavenger. Moreover, the level of Akt and procaspase-3 were increased, while the ratio of LC3 II/I was decreased. Taken together, our study demonstrates that the inhibitory effect of SZC015 against H322 cells is mediated by excessive ROS generation that could suppress Akt/NF-κB signaling pathway, which thereby leads to apoptotic and autophagic cell death.

Tubeimoside-1 induces oxidative stress-mediated apoptosis and G0/G1 phase arrest in human prostate carcinoma cells in vitro

AIM

Tubeimoside-1 (TBMS1), a triterpenoid saponin extracted from the Chinese herbal medicine Bolbostemma paniculatum (Maxim) Franquet (Cucurbitaceae), has shown anticancer activities in various cancer cell lines. The aim of this study was to investigate the anticancer activity and molecular targets of TBMS1 in human prostate cancer cells in vitro.

METHODS

DU145 and P3 human prostate cancer cells were treated with TBMS1. Cell viability and apoptosis were detected. ROS generation, mitochondrial membrane potential and cell cycle profile were examined. Western blotting was used to measure the expression of relevant proteins in the cells.

RESULTS

TBMS1 (5-100 μmol/L) significantly suppressed the viability of DU145 and P3 cells with IC50 values of approximately 10 and 20 μmol/L, respectively. Furthermore, TBMS1 dose-dependently induced apoptosis and cell cycle arrest at G0/G1 phase in DU145 and P3 cells. In DU145 cells, TBMS1 induced mitochondrial apoptosis, evidenced by ROS generation, mitochondrial dysfunction, endoplasmic reticulum stress, modulated Bcl-2 family protein and cleaved caspase-3, and activated ASK-1 and its downstream targets p38 and JNK. The G0/G1 phase arrest was linked to increased expression of p53 and p21 and decreased expression of cyclin E and cdk2. Co-treatment with Z-VAD-FMK (pan-caspase inhibitor) could attenuate TBMS1-induced apoptosis but did not prevent G0/G1 arrest. Moreover, co-treatment with NAC (ROS scavenger), SB203580 (p38 inhibitor), SP600125 (JNK inhibitor) or salubrinal (ER stress inhibitor) significantly attenuated TBMS1-induced apoptosis.

CONCLUSION

TBMS1 induces oxidative stress-mediated apoptosis in DU145 human prostate cancer cells in vitro via the mitochondrial pathway.

Killing cancer with platycodin D through multiple mechanisms

Cancer is a multi-faceted disease comprised of a combination of genetic, epigenetic, metabolic and signalling aberrations which severely disrupt the normal homoeostasis of cell growth and death. Rational developments of highly selective drugs which specifically block only one of the signalling pathways have been associated with limited therapeutic success. Multi-targeted prevention of cancer has emerged as a new paradigm for effective anti-cancer treatment. Platycodin D, a triterpenoid saponin, is one the major active components of the roots of Platycodon grandiflorum and possesses multiple biological and pharmacological properties including, anti-nociceptive, anti-atherosclerosis, antiviral, anti-inflammatory, anti-obesity, immunoregulatory, hepatoprotective and anti-tumour activities. Recently, the anti-cancer activity of platycodin D has been extensively studied. The purpose of this review was to give our perspectives on the current status of platycodin D and discuss its anti-cancer activity and molecular mechanisms which may help the further design and conduct of pre-clinical and clinical trials to develop it successfully into a potential lead drug for oncological therapy. Platycodin D has been shown to fight cancer by inducing apoptosis, cell cycle arrest, and autophagy and inhibiting angiogenesis, invasion and metastasis by targeting multiple signalling pathways which are frequently deregulated in cancers suggesting that this multi-target activity rather than a single effect may play an important role in developing platycodin D into potential anti-cancer drug.