Plumbagin attenuates cancer cell growth and osteoclast formation in the bone microenvironment of mice

Germacrone alleviates breast cancer-associated osteolysis by inhibiting osteoclastogenesis via inhibition of MAPK/NF-κB signaling pathways

Bone is one of the most frequent sites for metastasis in breast cancer patients. Bone metastasis significantly reduces the survival time and the life quality of breast cancer patients. Germacrone (GM) can serve humans as an anti-cancer and anti-inflammation agent, but its effect on breast cancer-induced osteolysis remains unclear. This study aims to investigate the functions and mechanisms of GM in alleviating breast cancer-induced osteolysis. The effects of GM on osteoclast differentiation, bone resorption, F-actin ring formation, and gene expression were examined in vitro. RNA-sequencing and Western Blot were conducted to explore the regulatory mechanisms of GM on osteoclastogenesis. The effects of GM on breast cancer-induced osteoclastogenesis, and breast cancer cell malignant behaviors were also evaluated. The in vivo efficacy of GM in the ovariectomy model and breast cancer bone metastasis model with micro-CT and histomorphometry. GM inhibited osteoclastogenesis, bone resorption and F-actin ring formation in vitro. Meanwhile, GM inhibited the expression of osteoclast-related genes. RNA-seq analysis and Western Blot confirmed that GM inhibited osteoclastogenesis via inhibition of MAPK/NF-κB signaling pathways. The in vivo mouse osteoporosis model further confirmed that GM inhibited osteolysis. In addition, GM suppressed the capability of proliferation, migration, and invasion and promoted the apoptosis of MDA-MB-231 cells. Furthermore, GM could inhibit MDA-MB-231 cell-induced osteoclastogenesis in vitro and alleviate breast cancer-associated osteolysis in vivo human MDA-MB-231 breast cancer bone metastasis-bearing mouse models. Our findings identify that GM can be a promising therapeutic agent for patients with breast cancer osteolytic bone metastasis.

Morusin inhibits breast cancer-induced osteolysis by decreasing phosphatidylinositol 3-kinase (PI3K)-mTOR signalling

Bone metastases caused by breast cancer pose a major challenge to the successful treatment of breast cancer patients. Many researchers have suggested that herbal medicines are extremely effective at preventing and treating cancer-associated osteolysis. Previous studies have revealed that Morusin (MOR) is cytotoxic to many cancer cells ex vivo. Nevertheless, how MOR contributes to osteolysis induced by breast cancer is still unknown, and the potential mechanism of action against osteolysis is worthy of further study. The protective effect and molecular mechanism of MOR in inhibiting breast cancer cell-induced osteolysis were verified by experiments and network pharmacology. Cell function was assessed by cell proliferation, osteoclast (OC) formation, bone resorption, and phalloidin staining. Tumour growth was examined by micro-CT scanning in vivo. To identify potential MOR treatments, the active ingredient-target pathway of breast cancer was screened using network pharmacology and molecular docking approaches. This study is the first to report that MOR can prevent osteolysis induced by breast cancer cells. Specifically, our results revealed that MOR inhibits RANKL-induced osteoclastogenesis and restrains the proliferation, invasion and migration of MDA-MB-231 breast cells through restraining the PI3K/AKT/MTOR signalling pathway. Notably, MOR prevented bone loss caused by breast cancer cell-induced osteolysis in vivo, indicating that MOR inhibited the development of OCs and the resorption of bone, which are essential for cancer cell-associated bone distraction. This study showed that MOR treatment inhibited osteolysis induced by breast cancer in vivo. MOR inhibited OC differentiation and bone resorption ex vivo and in vivo and might be a potential drug candidate for treating breast cancer-induced osteolysis.

Pogostone attenuates osteolysis in breast cancer by inhibiting the NF-kB and JNK signaling pathways of osteoclast

AIMS

Breast cancer is the most prevalent cancer in females, and approximately 70 % of all patients have evidence of metastatic bone disease, which substantially affects the quality of life and survival rate of breast cancer patients. Osteoporosis has become a global public health problem, and the abnormal activation of osteoclasts is the key to the progression of osteoporosis and the key to both diseases lies in the osteoclasts. Effective drug treatments are lacking and there is an urgent need to explore new drugs.

MATERIALS AND METHODS

We observed the effects of pogostone (PO) on osteoclast differentiation, bone resorption function and other indicators, and F-actin ring formation by using Trap staining, SEM and immunofluorescence, and further explored the targets of pogostone in regulating osteoclast differentiation and function using qPCR and Western Blot. In addition, we used CCK 8, Transwell, and flow cytometry to study the effects of pogostone on proliferation, invasion, migration, and apoptosis of MDA-MB-231 cells. Animal models were also constructed for in vivo validation.

KEY FINDINGS

Pogostone inhibits osteoclast differentiation, bone resorption, formation of F-actin ring, and the expression of specific genes by attenuated NF-kB degradation and phosphorylation of JNK. In vitro, pogostone suppresses invasion of breast cancer cells, migration, and promotes their apoptosis. In mouse models, pogostone attenuated osteoclast formation and bone resorption, blocked breast cancer cells migration, and supprsed breast cancer-induced osteolysis and ovariectomized (OVX)-mediated osteoporosis.

SIGNIFICANCE

These biological functions of pogostone make it a potential drug for treatment of breast cancer-associated bone metastasis in the future.

Polyphyllin VII protects from breast cancer-induced osteolysis by suppressing osteoclastogenesis via c-Fos/NFATc1 signaling

Bone is a preferred metastatic site of advanced breast cancer and the 5-year overall survival rate of breast cancer patients with bone metastasis is only 22.8%. Targeted inhibition of osteoclasts can treat skeletal-related events (SREs) in breast cancer patients. Polyphyllin VII (PP7), a pennogenyl saponin isolated from traditional Chinese herb Paris polyphylla, exhibits strong anti-inflammatory and anti-cancer activities. In this study, we evaluated the effect of PP7 on metastatic breast cancer-induced bone destruction in vivo and the underlying mechanisms. We found that intraperitoneal injection of 1 mg/kg PP7 significantly ameliorated the breast cancer MDA-MB-231 cell-induced osteolysis in mice. Mechanistically, PP7 (0.125-0.5 μM) inhibited the conditioned medium of MDA-MB-231 cells (MDA-MB-231 CM)-induced osteoclast formation in bone marrow-derived macrophages (BMMs). Furthermore, PP7 markedly reduced MDA-MB-231 CM-induced osteoclastic bone resorption and F-actin rings formation in vitro. During MDA-MB-231 CM-induced osteoclastogenesis, the activation of c-Fos and NFATc1 signaling was significantly downregulated by PP7, and finally osteoclast-related genes such as Oscar, Atp6v0d2, Mmp9 and β3 integrin were decreased. In addition, the formation of osteoblast was promoted by PP7 treatment. Our current findings revealed PP7 as a potential safe agent for preventing and treating bone destruction in breast cancer patients with bone metastases.

Plumbagin attenuates Bleomycin-induced lung fibrosis in mice

Background

Idiopathic pulmonary fibrosis (IPF) is a fatal fibrotic lung disease with limited treatment options. Plumbagin (PL) is an herbal extract with diverse pharmacological effects that have been recently used to treat various types of cancer. This study aims to explore the anti-fibrotic effect of PL and possible underlying mechanisms in IPF.

Methods

We used a bleomycin-induced experimental mouse model of lung fibrosis to assess the potential anti-fibrotic effect of PL. Histological analysis of lung tissue samples by H&E and Masson’s trichrome staining and hydroxyproline assay was performed to evaluate the fibrotic alterations. ELISA and real-time quantitative PCR were conducted to determine the amount of tumor necrosis factor-alpha (TNFα), tumor growth factor-beta (TGF-β), connective tissue growth factor (CTGF), and endothelin-1 (ET-1).

Results

Bleomycin exposure induced lung fibrosis, which was indicated by inflammation, collagen deposition, and structural damage. PL remarkably prevented bleomycin-induced lung fibrosis. Furthermore, PL significantly inhibited TNF-α and TGF-β production. PL also diminished the upregulated expression of CTGF and ET-1 induced by bleomycin.

Conclusion

Overall, our findings suggest PL as an anti-fibrotic agent acting via down-regulation of TGF-β/CTGF or ET-1 axis, as well as TNF-α, to improve lung fibrosis.

Plumbagin is a NF-κB-inducing kinase inhibitor with dual anabolic and antiresorptive effects that prevents menopausal-related osteoporosis in mice

Osteoporosis is caused by enhanced bone resorption and relatively reduced bone formation. There is an unmet need to develop new agents with both antiresorptive and anabolic effects to treat osteoporosis, although drugs with either effect alone are available. A small molecular compound, plumbagin, was reported to inhibit receptor activator of nuclear factor kappa-B ligand-induced osteoclast (OC) differentiation by inhibiting IκBα phosphorylation-mediated canonical NF-κB activation. However, the key transcriptional factor RelA/p65 in canonical NF-κB pathway functions to promote OC precursor survival but not terminal OC differentiation. Here, we found that plumbagin inhibited the activity of NF-κB inducing kinase, the key molecule that controls noncanonical NF-κB signaling, in an ATP/ADP-based kinase assay. Consistent with this, plumbagin inhibited processing of NF-κB2 p100 to p52 in the progenitor cells of both OCs and osteoblasts (OBs). Interestingly, plumbagin not only inhibited OC but also stimulated OB differentiation in vitro. Importantly, plumbagin prevented trabecular bone loss in ovariectomized mice. This was associated with decreased OC surfaces on trabecular surface and increased parameters of OBs, including OB surface on trabecular surface, bone formation rate, and level of serum osteocalcin, compared to vehicle-treated mice. In summary, we conclude that plumbagin is a NF-κB-inducing kinase inhibitor with dual anabolic and antiresorptive effects on bone and could represent a new class of agent for the prevention and treatment of osteoporosis.

The phytochemical plumbagin reciprocally modulates osteoblasts and osteoclasts

Bone metabolism is essential for maintaining bone mineral density and bone strength through a balance between bone formation and bone resorption. Bone formation is associated with osteoblast activity whereas bone resorption is linked to osteoclast differentiation. Osteoblast progenitors give rise to the formation of mature osteoblasts whereas monocytes are the precursors for multi-nucleated osteoclasts. Chronic inflammation, auto-inflammation, hormonal changes or adiposity have the potential to disturb the balance between bone formation and bone loss. Several plant-derived components are described to modulate bone metabolism and alleviate osteoporosis by enhancing bone formation and inhibiting bone resorption. The plant-derived naphthoquinone plumbagin is a bioactive compound that can be isolated from the roots of the Plumbago genus. It has been used as traditional medicine for treating infectious diseases, rheumatoid arthritis and dermatological diseases. Reportedly, plumbagin exerts its biological activities primarily through induction of reactive oxygen species and triggers osteoblast-mediated bone formation. It is plausible that plumbagin's reciprocal actions - inhibiting or inducing death in osteoclasts but promoting survival or growth of osteoblasts - are a function of the synergy with bone-metabolizing hormones calcitonin, Parathormone and vitamin D. Herein, we develop a framework for plausible molecular modus operandi of plumbagin in bone metabolism.

Plumbagin Suppresses Pulmonary Fibrosis via Inhibition of p300 Histone Acetyltransferase Activity

Idiopathic pulmonary fibrosis (IPF) is a chronic fibrosing interstitial lung disease with a poor prognosis similar to that of malignancy. The causes of IPF are not clearly known, and there is no effective therapy to date. In this study, the natural compound plumbagin, which was isolated from Plumbago rosea root extract, was screened for p300 inhibitory activity. Plumbagin specifically inhibited the activity of p300 toward histone acetyltransferases. Plumbagin treatment significantly suppressed transforming growth factor-β-induced profibrotic target-gene expression and proliferation of fibroblast cell lines. Moreover, plumbagin significantly inhibited bleomycin-induced pulmonary fibrosis in mice. Taken together, these data demonstrate the inhibitory effects of plumbagin on lung fibrosis and its promise as a therapeutic agent for IPF.

Mycobacterium tuberculosis thymidylate synthase (ThyX) is a target for plumbagin, a natural product with antimycobacterial activity

Plumbagin derived from the plant Plumbago indica, known as Chitrak in India, is an example of a medicinal compound used traditionally to cure a variety of ailments. Previous reports have indicated that it can inhibit the growth of Mycobacterium tuberculosis (Mtb), the causative agent of the deadly disease TB. In this investigation, we provide an insight into its mode of action. We show here that a significant mycobacterial target that is inhibited by plumbagin is the enzyme ThyX, a form of thymidylate synthase, that is responsible for the synthesis of dTMP from dUMP in various bacterial pathogens, including Mtb. Using a purified preparation of the recombinant version of Mtb ThyX, we demonstrate that plumbagin, a 2,4 napthoquinone, but not lawsone, a structurally related medicinal compound, inhibits its activity in vitro. We also show that the intracellular [dTTP]/[dATP] ratio in Mycobacterium smegmatis (Msm) cells decrease upon treatment with plumbagin, and this, in turn, leads to cell death. Such a conclusion is supported by the observation that over-expression of thyx in the plumbagin treated Msm cells leads to the restoration of viability. The results of our investigation indicate that plumbagin kills mycobacterial cells primarily by targeting ThyX, a vital enzyme required for their survival.

Emerging role of plumbagin: Cytotoxic potential and pharmaceutical relevance towards cancer therapy

Plumbagin is a naphthoquinone derived yellow crystalline phytochemical. Plumbagin has a wide range of biological effects including cytotoxicity against cancer cells both in vitro and in vivo. Due to the pleiotropic nature of plumbagin, it shows the anticancer effect by targeting several molecular mechanisms including apoptosis and autophagic pathways, cell cycle arrest, anti-angiogenic pathways, anti-invasion and anti-metastasis pathways. Among many signaling pathways the key regulatory genes regulated by plumbagin are NF-kβ, STAT3, and AKT, etc. Plumbagin is also a potent inducer of ROS, suppressor of cellular glutathione, and causes DNA strand break by oxidative DNA base damages. In vivo studies suggested that plumbagin significantly reduces the tumor weight and volume in dose-dependent manner without any side effects in tested model organisms. Another exciting aspect of plumbagin is the ability to re-sensitize the chemo and radioresistant cancer cells when used in combination or alone. Nano encapsulation of plumbagin overcomes the poor water solubility and bioavailability obstacles, enhancing the pharmaceutical relevance with better therapeutic efficacy. Moreover, plumbagin can be introduced as a future phytotherapeutic anticancer drug after fully satisfied preclinical and clinical trials.

Plumbagin Ameliorates Collagen-Induced Arthritis by Regulating Treg/Th17 Cell Imbalances and Suppressing Osteoclastogenesis

Objective: Plumbago zeylanica L. (with plumbagin as its active ingredients) has been used for centuries to treat conditions such as joint swelling, fractures, and bacterial infections, suggesting that it possesses anti-inflammatory and immunosuppressive properties. In the present study, we evaluated the potential anti-arthritic activity and related mechanisms of plumbagin.

Methods: Collagen-induced arthritis (CIA) was initiated in Wistar rats with collagen type II. Plumbagin (2 and 6 mg/kg) was orally administered to rats with CIA from day 12 to day 32 post immunization. The effects of plumbagin on arthritis progression were assessed by paw swelling, clinical scoring, and histologic analysis. The percentage of Treg and Th17 were defined by flow cytometry or immunofluorescence (IF) staining. Bone erosion and resorption were assessed by micro-CT and histomorphometric analysis. Osteoclast differentiation was further determined by in vitro osteoclastogenesis assay. The molecular docking assay was used to determine the potential binding site of plumbagin.

Results: Treatment with plumbagin significantly inhibited arthritis development, as well as suppressed the local and systemic inflammation. Plumbagin reciprocally regulated pro-inflammatory Th17 cell and immunosuppressive Treg cell populations. In addition, plumbagin protected inflammation-induced bone loss by inhibiting osteoclast formation and activity. Plumbagin markedly suppressed RANKL-stimulated osteoclast-specific gene expression by repressing NF-κB signaling activation and MAP kinase phosphorylation. Further study via molecular docking assay demonstrated that plumbagin bound to MET169 of JNK kinase and LYS138 and SER183 of p38 kinase.

Conclusion: Plumbagin not only attenuates the immune-induced arthritis by inhibiting inflammation, but also protects bone erosion by directly inhibiting osteoclast formation and activity. These data suggest plumbagin is a promising new candidate drug for treating inflammatory joint diseases.

Plumbagin-Loaded Nanoemulsion Drug Delivery Formulation and Evaluation of Antiproliferative Effect on Prostate Cancer Cells

Background

Plumbagin, a medicinal plant-derived 5-hydroxy-2-methyl-1,4-naphthoquinone, is an emerging drug with a variety of pharmacological effects, including potent anticancer activity. We have previously shown that plumbagin improves the efficacy of androgen deprivation therapy (ADT) in prostate cancer and it is now being evaluated in phase I clinical trial. However, the development of formulation of plumbagin as a compound with sparing solubility in water is challenging.

Methods

We have formulated plumbagin-loaded nanoemulsion using pneumatically controlled high pressure homogenization of oleic acid dispersions with polyoxyethylene (20) sorbitan monooleate as surfactant. Nanoemulsion formulations were characterized for particle size distribution by dynamic light scattering (DLS). The kinetics of in vitro drug release was determined by equilibrium dialysis. Anticancer activity toward prostate cancer cells PTEN-P2 was assessed by MTS (Owen's reagent) assay.

Results

Particle size distribution of nanoemulsions is tunable and depends on the surfactant concentration. Nanoemulsion formulations of plumbagin with 1-3.5% (w/w) of surfactant showed robust stability of size distribution over time. Plumbagin-loaded nanoemulsion with average hydrodynamic diameter of 135 nm showed exponential release of plumbagin with a half-life of 6.1 h in simulated gastric fluid, 7.0 h in simulated intestinal fluid, and displayed enhanced antiproliferative effect toward prostate cancer cells PTEN-P2 compared to free plumbagin.

Conclusion

High drug-loading capacity, retention of nanoparticle size, kinetics of release under simulated physiological conditions, and increased antiproliferative activity indicate that oleic-acid based nanoemulsion formulation is a suitable delivery system of plumbagin.

Systematic Overview of Bacopa monnieri (L.) Wettst. Dominant Poly-Herbal Formulas in Children and Adolescents

Background: The Ayurvedic medicinal system employs a holistic approach to health, utilising the synergistic properties of organic resources. Research into the Ayurvedic herb Bacopa monnieri (L.) Wettst. (B.monnieri) has reported improvements in cognitive outcomes in child and adult populations. The aim of current review is to systematically assess and critically summarize clinical trials investigating B.monnieri-dominant poly-herbal formulas and their effects on the cognition, memory, learning, and behaviour in children and adolescents. Methods: Key word searches were performed using PubMed, Scopus, Cochrane Library, DHARA, and CINAHL for publications meeting inclusion criteria up to November 2017. There were no restrictions in study design. Effect sizes were calculated for all significant findings to allow for direct comparisons, and each study was evaluated on design quality. Cognitive and behavioural outcomes were grouped into validated constructs for cross-study comparison. Results: Nine trials met inclusion criteria. Five studies reported sufficient data for effect size analysis with most improvements reported in behavioural outcomes. True cognitive abilities and behavioural constructs were reviewed in six studies, with visual perception, impulsivity, and attention demonstrating the greatest improvements. The veracity of the evidence for the formulations reviewed is weakened by inconsistent statistical design and under-reporting of safety and tolerability data (44%). Conclusions: The current review extends research supporting B.monnieri as a cognitive enhancer and provides modest evidence for the use of B.monnieri in poly-herbal preparations for improving cognitive and behavioural outcomes in child and adolescent populations. Greater emphasis on statistical vigour and the reporting of tolerability data are essential for future trials to adequately document poly-herbal treatment efficacy.

Plumbagin suppresses chronic periodontitis in rats via down-regulation of TNF-α, IL-1β and IL-6 expression

Chronic periodontitis (CP) is one of the most common oral diseases, which causes alveolar bone absorption and tooth loss in adults. In this study we aimed to investigate the potential of plumbagin (PL), a widely-investigated active compound extracted from the traditional Chinese herb Plumbago zeylanica L in treating CP. Human periodontal ligament stem cells (PDLSCs) were used for in vitro studies, whereas an animal model of CP was established in SD rats by ligation+Porphyromonas gingivalis (Pg) stimulation. The rats were injected with PL (2, 4, and 6 mg·kg^-1·d^-1, ip) for 4 weeks. Treatment of PDLSCs with TNF-α (10 ng/mL) markedly stimulated the expression of the proinflammatory cytokines TNF-α, IL-1β and IL-6, as well as the chemokines CCL-2 and CCL-5, which were dose-dependently suppressed by co-treatment with PL (1.25-5 μmol/L). Furthermore, PL (3.75 μmol/L) markedly suppressed TNF-α-induced activation of the MAPK, NF-κB and JAK/STAT signaling pathways in PDLSCs. In consistence with the in vitro studies, PL administration significantly decreased the expression of TNF-α, IL-1β and IL-6 in gingiva of the rat with CP, with the dosage 4 mg·kg^-1·d^-1 showing the best anti-inflammatory effect. Moreover, PL administration decelerated bone destruction in the rat with CP, evidenced by the aveolar bone loss (ABL) and H&E staining results. In conclusion, PL suppresses CP progression in rats by downregulating the expressions of TNF-α, IL-1β and IL-6 and inhibiting the MAPK, NF-κB and JAK/STAT signaling pathways.

Anticancer Properties and Pharmaceutical Applications of Plumbagin: A Review

It has been shown that plumbagin, a bioactive naphthoquinone isolated from three major plant families viz. Plumbaginaceae, Ebenceae and Droseraceae, definitively exhibits anticancer potential in diverse cancer cells both in vitro and in vivo. Plumbagin shows antineoplastic effects via multi-channel molecular mechanisms, including the induction of apoptosis and autophagy, the disruption of the cell cycle, the inhibition of invasion and metastasis, and anti-angiogenesis. Plumbagin inhibits the growth of cancer cells mainly through the modulation of the signals of PI3K/Akt/mTOR, AMPK, Ras, and so on. The pharmaceutical applications of plumbagin combined with nanocarriers to achieve better therapeutic efficiency are discussed in this review Among them, liposomes, nanoparticles, microspheres, micelles, and nisosomes are used in cancer treatment. The anticancer study of plumbagin in vivo is also summarized in this review. On the whole, we aim to review the research progress of plumbagin both in pharmacological and pharmaceutical filed, which may provide some reference for further research of plumbagin.

Cancer Chemoprevention by Phytochemicals: Nature's Healing Touch

Phytochemicals are an important part of traditional medicine and have been investigated in detail for possible inclusion in modern medicine as well. These compounds often serve as the backbone for the synthesis of novel therapeutic agents. For many years, phytochemicals have demonstrated encouraging activity against various human cancer models in pre-clinical assays. Here, we discuss select phytochemicals—curcumin, epigallocatechin-3-gallate (EGCG), resveratrol, plumbagin and honokiol—in the context of their reported effects on the processes of inflammation and oxidative stress, which play a key role in tumorigenesis. We also discuss the emerging evidence on modulation of tumor microenvironment by these phytochemicals which can possibly define their cancer-specific action. Finally, we provide recent updates on how low bioavailability, a major concern with phytochemicals, is being circumvented and the general efficacy being improved, by synthesis of novel chemical analogs and nanoformulations.

Gastrodin inhibits osteoclastogenesis via down-regulating the NFATc1 signaling pathway and stimulates osseointegration in vitro

Bone is a rigid yet dynamic organ, and this dynamism is mediated by the delicate balance between osteoclastic bone resorption and osteoblastic bone formation. However, excessive activation of osteoclasts is responsible for many bone diseases such as osteoporosis, Paget disease, and tumor bone metastasis. Agents that could inhibit osteoclast formation or function are regarded as promising alternatives to treat osteoclast-related diseases. Recently, traditional Chinese medicine has attracted attention because of its multiple activities in bone metabolism. Among them, gastrodin has been reported as an anti-osteoporosis agent that reduces reactive oxygen species. However, the direct action of gastrodin on osteoclast differentiation and bone resorption, and its underlying molecular mechanism, remain unknown. In this study, we investigated the effects of gastrodin on receptor activator NF-κB ligand (RANKL)-activated osteoclasts formation and bone resorption. Our results showed that gastrodin retarded RANKL-induced osteoclast differentiation efficiently by downregulating transcriptional and translational expression of nuclear factor of activated T cells cl (NFATc1), a major factor in RANKL-mediated osteoclastogenesis. Meanwhile, gastrodin prevented osteoclast maturation and migration by inhibiting the gene expression of dendrocyte expressed seven transmembrane protein (DC-STAMP), an osteoclastic-specific gene that controls cells fusion and movement. And gastrodin prevented RANKL-induced osteoclastic bone erosion in vitro. In addition, gastrodin also stimulated bone mesenchymal stem cell (BMSC) spreading and osseointegration in titanium plate. In summary, gastrodin could prevent osteoclasts formation and bone resorption via blockage of NFATc1 activity, and stimulate osseointegration in vitro. Gastrodin could be developed as a potent phytochemical candidate to treat osteolytic diseases.

Kinsenoside screening with a microfluidic chip attenuates gouty arthritis through inactivating NF-κB signaling in macrophages and protecting endothelial cells

Gouty arthritis is a rheumatic disease that is characterized by the deposition of monosodium urate (MSU) in synovial joints cause by the increased serum hyperuricemia. This study used a three-dimensional (3D) flowing microfluidic chip to screen the effective candidate against MSU-stimulated human umbilical vein endothelial cell (HUVEC) damage, and found kinsenoside (Kin) to be the leading active component of Anoectochilus roxburghi, one of the Chinese medicinal plant widely used in the treatment of gouty arthritis clinically. Cell viability and apoptosis of HUVECs were evaluated, indicating that direct Kin stimulation and conditioned medium (CM) from Kin-treated macrophages both negatively modulated with MSU crystals. Additionally, Kin was capable of attenuating MSU-induced activation of nuclear factor-κB/mitogen-activated protein kinase (NF-κB/MAPK) signaling, targeting IκB kinase-α (IKKα) and IKKβ kinases of macrophages and influencing the expressions of NF-κB downstream cytokines and subsequent HUVEC bioactivity. Inflammasome NLR pyrin domain-containing 3 (NALP3) and toll-like receptor 2 (TLR2) were also inhibited after Kin treatment. Also, Kin downregulated CD14-mediated MSU crystals uptake in macrophages. In vivo study with MSU-injected ankle joints further revealed the significant suppression of inflammatory infiltration and endothelia impairment coupled with alleviation of ankle swelling and nociceptive response via Kin treatments. Taken together, these data implicated that Kin was the most effective candidate from Anoectochilus roxburghi to treat gouty arthritis clinically.

Plumbagin Enhances Tamoxifen Sensitivity and Inhibits Tumor Invasion in Endocrine Resistant Breast Cancer through EMT Regulation

Tamoxifen is widely used as the first line drug for estrogen receptor-positive subtype which is expressed in 70% of overall breast cancer patients. However, approximately 50% of these patients develop acquired resistance after 5 years of treatment, which is characterized by tumor recurrence and metastasis. The epithelial mesenchymal transition (EMT) is an important process in breast cancer invasion. Fundamentally, targeting the EMT represents a crucial therapeutic strategy for preventing or treating breast cancer metastasis. Plumbagin (PLB) is a natural naphthoquinone with significant anticancer effects against several types of tumor cells including breast cancer. In this study, we investigated the effect of PLB on human endocrine-resistant breast cancer cell growth, invasion and the possible mechanisms underlying such actions. PLB exhibited potent cytotoxic activity at a micromolar concentration against endocrine-resistant breast cancer cells. Interestingly, a fixed low concentration of PLB and tamoxifen combination resulted in an increase in growth inhibition in endocrine-resistant cells. In addition, PLB also significantly suppressed mesenchymal biomarker expressions that govern the EMT process, resulting in attenuated metastatic capabilities. In conclusion, PLB should be developed as a pharmacological agent for the use as a single treatment or in combination for endocrine-resistant breast cancer. Copyright © 2016 John Wiley & Sons, Ltd.

Current Management Strategies in Breast Cancer by Targeting Key Altered Molecular Players

Breast cancer is the second largest disease affecting women worldwide. It remains the most frequently reported and leading cause of death among women in both developed and developing countries. Tamoxifen and raloxifene are commonly used selective estrogen receptor modulators for treatment of breast cancer in women with high risk, although resistance occurs by tamoxifen after 5 years of therapy and both drugs cause uterine cancer and thromboembolic events. Aromatase inhibitors (AIs) are one of the optional modes used for breast cancer treatment. The combination of AIs along with tamoxifen can also be beneficial. Various therapeutic agents from different sources are being studied, which further need to be improved for potential outcome. For this, clinical trials based on large number of patients with optimal dose and lesser side effects have to be more in practice. Despite the clinical trials going on, there is need of better molecular models, which can identify high risk population, new agents with better benefit having less side effects, and improved biomarkers for treating breast cancer.

Structural simulation of adenosine phosphate via plumbagin and zoledronic acid competitively targets JNK/Erk to synergistically attenuate osteoclastogenesis in a breast cancer model

The treatment of breast cancer-induced osteolysis remains a challenge in clinical settings. Here, we explored the effect and mechanism of combined treatment with zoledronic acid (ZA) and plumbagin (PL), a widely investigated component derived from Plumbago zeylanica, against breast cancer-induced osteoclastogenesis. We found that the combined treatment with PL and ZA suppressed cell viability of precursor osteoclasts and synergistically inhibited MDA-MB-231-induced osteoclast formation (combination index=0.28) with the abrogation of recombinant mouse receptor activator of nuclear factor-κB ligand (RANKL)-induced activation of NF-κB/MAPK (nuclear factor-κB/mitogen-activated protein kinase) pathways. Molecular docking suggested a putative binding area within c-Jun N-terminal kinase/extracellular signal-regulated kinase (JNK/Erk) protease active sites through the structural mimicking of adenosine phosphate (ANP) by the spatial combination of PL with ZA. A homogeneous time-resolved fluorescence assay further illustrated the direct competitiveness of the dual drugs against ANP docking to phosphorylated JNK/Erk, contributing to the inhibited downstream expression of c-Jun/c-Fos/NFATc-1 (nuclear factor of activated T cells, cytoplasmic, calcineurin-dependent 1). Then, in vivo testing demonstrated that the combined administration of PL and ZA attenuated breast cancer growth in the bone microenvironment. Additionally, these molecules prevented the destruction of proximal tibia, with significant reduction of tartrate-resistant acid phosphatase (TRAcP)-positive osteoclast cells and potentiation of apoptotic cancer cells, to a greater extent when combined than when the drugs were applied independently. Altogether, the combination treatment with PL and ZA could significantly and synergistically suppress osteoclastogenesis and inhibit tumorigenesis both in vitro and in vivo by simulating the spatial structure of ANP to inhibit competitively phosphorylation of c-Jun N-terminal kinase/extracellular signal-regulated kinase (JNK/Erk).

Synergistic suppression of human breast cancer cells by combination of plumbagin and zoledronic acid In vitro

AIM

Zoledronic acid (ZA), a bisphosphonate, is currently used in combination with chemotherapeutic agents to suppress breast cancer cell proliferation or breast cancer-induced osteolysis. The aim of this study was to investigate the effects of ZA combined with a natural anticancer compound plumbagin (PL) against human breast cancer cells in vitro.

METHODS

Human breast cancer MDA-MB-231SArfp cells were treated with ZA, PL or a combination of ZA and PL. The cell growth, apoptosis and migration were evaluated using CCK-8 assay, flow cytometry and transwell assay, respectively. The expression of apoptosis-related proteins was measured using real-time PCR and Western blotting. Synergism was evaluated using Compusyn software, and the combination index (CI) and drug reduction index (DRI) values were determined.

RESULTS

PL or ZA alone caused mild cytotoxicity (the IC50 value at 24 h was 12.18 and above 100 μmol/L, respectively). However, the combination of ZA and PL caused a synergistic cytotoxicity (CI=0.26). The DRI values also showed a synergistic effect between PL and ZA, with actual values of 5.52 and 3.59, respectively. Furthermore, PL and ZA synergistically induced apoptosis and inhibited migration of the breast cancer cells. Moreover, the combination of ZA and PL decreased the expression of Notch-1, cleaved PARP, Bcl-2 and Bcl-xl, and increased the expression of cleaved caspase-3, CDKN1A and ID1. When the breast cancer cells were transfected with specific siRNA against Notch-1, the combination of ZA and PL markedly increased the expression of Bcl-2.

CONCLUSION

Combination of ZA and PL synergistically suppresses human breast cancer MDA-MB-231SArfp cells in vitro. PL can inhibit ZA-induced activation of the Notch-1 signaling pathway and subsequently reduce the expression of Bcl-2, thus potentiating cancer cell apoptosis.

Plumbagin Inhibits Prostate Carcinogenesis in Intact and Castrated PTEN Knockout Mice via Targeting PKCε, Stat3, and Epithelial-to-Mesenchymal Transition Markers

Prostate cancer continues to remain the most common cancer and the second leading cause of cancer-related deaths in American males. The Pten deletions and/or mutations are frequently observed in both primary prostate cancers and metastatic prostate tissue samples. Pten deletion in prostate epithelium in mice results in prostatic intraepithelial neoplasia (PIN), followed by progression to invasive adenocarcinoma. The Pten conditional knockout mice [(Pten-loxp/loxp:PB-Cre4(+)) (Pten-KO)] provide a unique preclinical model to evaluate agents for efficacy for both the prevention and treatment of prostate cancer. We present here for the first time that dietary plumbagin, a medicinal plant-derived naphthoquinone (200 or 500 ppm) inhibits tumor development in intact as well as castrated Pten-KO mice. Plumbagin has shown no signs of toxicity at either of these doses. Plumbagin treatment resulted in a decrease expression of PKCε, AKT, Stat3, and COX2 compared with the control mice. Plumbagin treatment also inhibited the expression of vimentin and slug, the markers of epithelial-to-mesenchymal transition (EMT) in prostate tumors. In summary, the results indicate that dietary plumbagin inhibits growth of both primary and castration-resistant prostate cancer (CRPC) in Pten-KO mice, possibly via inhibition of PKCε, Stat3, AKT, and EMT markers (vimentin and slug), which are linked to the induction and progression of prostate cancer.