Chrysosplenetin inhibits artemisinin efflux in P-gp-over-expressing Caco-2 cells and reverses P-gp/MDR1 mRNA up-regulated expression induced by artemisinin in mouse small intestine

High-throughput BCRP inhibitors screening system based on styrene maleic acid polymer membrane protein stabilization strategy and surface plasmon resonance biosensor

Multidrug resistance (MDR) is a dominant challenge in cancer chemotherapy failure. The over-expression of breast cancer resistance protein (BCRP) in tumorous cells, along with its extensive substrate profile, is a leading cause of tumor MDR. Herein, on the basis of styrene maleic acid (SMA) polymer membrane protein stabilization strategy and surface plasmon resonance (SPR) biosensor, a novel high-throughput screening (HTS) system for BCRP inhibitors has been established. Firstly, LLC-PK1 and LLC-PK1/BCRP cell membranes were co-incubated with SMA polymers to construct SMA lipid particles (SMALPs). PK1-SMALPs were thus immobilized in channel 1 of the L1 chip as the reference channel, and BCRP-SMALPs were immobilized in channel 2 as the detection channel to establish the BCRP-SMALPs-SPR screening system. The methodological investigation demonstrated that the screening system was highly specific and stable. Three active compounds were screened out from 26 natural products and their affinity constants with BCRP were determined. The KD of xanthotoxin, bergapten, and naringenin were 5.14 μM, 4.57 μM, and 3.72 μM, respectively. The in vitro cell verification experiments demonstrated that xanthotoxin, bergapten, and naringenin all significantly increased the sensitivity of LLC-PK1/BCRP cells to mitoxantrone with possessing reversal BCRP-mediated MDR activity. Collectively, the developed BCRP-SMALPs-SPR screening system in this study has the advantages of rapidity, efficiency, and specificity, providing a novel strategy for the in-depth screening of BCRP inhibitors with less side effects and higher efficacy.

Ophiopogonin D ameliorates non‑alcoholic fatty liver disease in high‑fat diet‑induced obese mice by improving lipid metabolism, oxidative stress and inflammatory response

Lipid metabolic disorders, oxidative stress and inflammation in the liver are key steps in the progression of non-alcoholic fatty liver disease (NAFLD). Ophiopogonin D (OP-D), the main active ingredient of Ophiopogon japonicus, exhibits several pharmacological activities such as antioxidant and anti-inflammatory activities. Therefore, the current study aimed to explore the role of OP-D in NAFLD in a high-fat diet (HFD)-induced obesity mouse model. To investigate the effect of OP-D on NAFLD in vivo, a NAFLD mouse model was established following feeding mice with HFD, then the mice were randomly treated with HFD or HFD + OP-D for 4 weeks. Subsequently, primary mouse hepatocytes were isolated, and enzyme-linked immunosorbent assay, reverse transcription-quantitative PCR western blotting and immunofluorescence analysis were used for assessment to explore the direct effect of OP-D in vitro. The results of the present study indicated that OP-D could ameliorate NAFLD in HFD-induced obese mice by regulating lipid metabolism and antioxidant and anti-inflammatory responses. Additionally, OP-D treatment decreased lipogenesis and inflammation levels in vitro, suggesting that the NF-κB signaling pathway may be involved in the beneficial effects of OP-D on NAFLD.

Antimalarial activity and sensitization of chrysosplenetin against artemisinin-resistant genotype Plasmodium berghei K173 potentially via dual-mechanism of maintaining host P-glycoprotein homeostasis mediated by NF-κB p52 or PXR/CAR signaling pathways and regulating heme/haemozoin metabolism

This study investigated antimalarial efficacy and sensitization of chrysosplenetin against artemisinin-resistant Plasmodium berghei K173 and potential molecular mechanism. Our data indicated a risk of artemisinin resistance because a higher parasitaemia% and lower inhibition% under artemisinin treatment against resistant parasites than those in the sensitive groups were observed. Two non-antimalarial components, verapamil and chrysosplentin, being P-gp inhibitors, possessed a strong efficacy against resistant parasites but it was not the case for Bcrp inhibitor novobiocin. Artemisinin-chrysosplenetin combination improved artemisinin susceptibility of resistant P. berghei. Artemisinin activated intestinal P-gp and Abcb1/Abcg2 expressions and suppressed Bcrp whereas chrysosplenetin reversed them. Resistant parasite infection led to a decreased haemozoin in organs or an increased heme in peripheral bloods compared with the sensitives; however, that in Abcb1-deficient knockout (KO)-resistant mice reversely got increased or decreased versus wild type (WT)-resistant animals. Chrysosplenetin as well as rifampin (nuclear receptor agonist) increased the transcription levels of PXR/CAR while showed a versatile regulation on hepatic and enternal PXR/CAR in WT- or KO-sensitive or -resistant parasites. Oppositely, hepatic and enteric NF-κB p52 mRNA decreased conformably in WT but increased in KO-resistant mice. NF-κB pathway potentially involved in the mechanism of chrysosplenetin on inhibiting P-gp expressions while PXR/CAR play a more complicated role in this mechanism.

Nontargeted metabolomics integrated with 1 H NMR and LC-Q-TOF-MS/MS methods to depict a more comprehensive metabolic profile in response to chrysosplenetin and artemisinin co-treatment against artemisinin-sensitive and -resistant Plasmodium berghei K173

Our previous work revealed mutual and specific metabolites/pathways in artemisinin-sensitive and -resistant Plasmodium berghei K173-infected mice. In this study, we further investigated whether chrysosplenetin, a candidate chemical to prevent artemisinin resistance, can regulate these metabolites/pathways by integrating nontargeted metabolomics with ¹ H NMR and LC-Q-TOF-MS/MS spectrum. The nuclear magnetic resonance method generated specifically altered metabolites in response to co-treatment with chrysosplenetin, including: the products of glycolysis such as glucose, pyruvate, lactate and alanine; taurine, closely associated with liver injury; arginine and proline as essential amino acids for parasites; TMAO, a biomarker for dysbacteriosis and renal function; and tyrosine, which is used to generate levodopa and dopamine and may improve the torpor state of mice. Importantly, we noticed that chrysosplenetin might depress the activated glycolysis induced by sensitive parasites, but oppositely promoted the inhibited glycolysis to generate more lactate, which suppresses the proliferation of resistant parasites. Moreover, chrysosplentin possibly disturbs the heme biosynthetic pathway in mitochondria. The MS method yielded changed coenzyme A, phosphatidylcholine and ceramides, closely related to mitochondria β-oxidation, cell proliferation, differentiation and apoptosis. These two means shared no overlapped metabolites and formed a more broader metabolic map to study the potential mechanisms of chrysosplenetin as a promising artemisinin resistance inhibitor.

The role of emodin on cisplatin resistance reversal of lung adenocarcinoma A549/DDP cell

Exploring drugs that reverse drug resistance and increase the sensitivity of chemotherapy drugs could significantly improve treatment effect of cancer. Our study explored the reversal effect and possible molecular mechanisms of emodin on cisplatin resistance in A549/DDP cells. The IC50 and resistance index of cells were determined by Cell Counting Kit-8 assay. The ability of cell proliferation was evaluated by wound healing assay. Transwell assay was used to detect cell invasion and migration. Apoptosis induction rate was determined by flow cytometry assay and 4',6- diamidino- 2-phenylindole staining. Intracellular concentration was determined by HPLC. Western blot analysis was applied to determine expressions of nuclear factor kappa beta (NF-κB) and its downstream proteins. In this study, we found that the growth inhibitory effect of cisplatin was significantly enhanced by emodin in A549/DDP cells. The combined use of emodin with DDP can effectively promote lung cancer cells apoptosis and inhibit cell migration and invasion. Further investigation indicated that reinforcement effect of emodin and DDP may be associated with inhibition of NF-κB pathway and drug efflux-related proteins such as P-glycoprotein (P-gp), multidrug resistance-associated protein (MRP) and Glutathione S-transferase (GST). The key role of NF-κB was further confirmed by the application of NF-κB inhibitor Ammonium pyrrolidinedithiocarbamate. The intervention of both can significantly increase A549/DDP cell apoptosis and inhibit DDP-induced upregulation of P-gp, MRP and GST. Emodin reverses the cisplatin resistance of tumor cells by down-regulating expression of P-gp, MRP and GST, increasing the intracellular accumulation in A549/DDP cells, and the effect may be associated with the NF-κB pathways.

QTMP, a Novel Thiourea Polymer, Causes DNA Damage to Exert Anticancer Activity and Overcome Multidrug Resistance in Colorectal Cancer Cells

Colorectal cancer (CRC) is one of the most common malignancies, and multidrug resistance (MDR) severely restricts the effectiveness of various anticancer drugs. Therefore, the development of novel anticancer drugs for the treatment of CRC patients with MDR is necessary. Quaternized thiourea main-chain polymer (QTMP) is a self-assembled nanoparticle with good water solubility. Notably, QTMP is not a P-glycoprotein (P-gp) substrate, and it exhibits potent cytotoxic activity against CRC cells, including HCT116/DDP and P-gp-mediated multidrug-resistant Caco2 cells. QTMP also exhibits a strong anticancer activity against SW480 cells in vivo. Interestingly, reactive oxygen species (ROS) and reactive nitrogen species (RNS) production were increased in a concentration-dependent manner in QTMP-treated HCT116, SW480 and Caco2 cells. Importantly, QTMP causes DNA damage in these CRC cells via direct insertion into the DNA or regulation of ROS and/or RNS production. QTMP also induces caspase-dependent apoptosis via overproduction of ROS and RNS. Therefore, QTMP is a promising anticancer therapeutic agent for patients with CRC, including those cancer cells with P-gp-mediated MDR. The present study also indicates that the design and synthesis of anticancer drugs based on thiourea polymers is promising and valuable, thereby offering a new strategy to address MDR, and provides reference resources for further investigations of thiourea polymers.

Stevia Genus: Phytochemistry and Biological Activities Update

The Stevia genus (Asteraceae) comprises around 230 species, distributed from the southern United States to the South American Andean region. Stevia rebaudiana, a Paraguayan herb that produces an intensely sweet diterpene glycoside called stevioside, is the most relevant member of this genus. Apart from S. rebaudiana, many other species belonging to the Stevia genus are considered medicinal and have been popularly used to treat different ailments. The members from this genus produce sesquiterpene lactones, diterpenes, longipinanes, and flavonoids as the main types of phytochemicals. Many pharmacological activities have been described for Stevia extracts and isolated compounds, antioxidant, antiparasitic, antiviral, anti-inflammatory, and antiproliferative activities being the most frequently mentioned. This review aims to present an update of the Stevia genus covering ethnobotanical aspects and traditional uses, phytochemistry, and biological activities of the extracts and isolated compounds.

MicroRNA-221 Upregulates the Expression of P-gp and Bcl-2 by Activating the Stat3 Pathway to Promote Doxorubicin Resistance in Osteosarcoma Cells

MicroRNA-221 (miRNA-221) is upregulated in several malignant tumors and is associated with poor patient prognosis. Therefore, the present study aimed to investigate the role and underlying mechanism of miRNA-221 in doxorubicin (DOX) resistance in osteosarcoma cells. We constructed DOX-resistant Saos-2/DOX cells and treated them with DOX. Cell viability was determined by performing a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cells were transfected with either miRNA-221 mimic or miRNA-221 inhibitor; quantitative (q)RT-PCR was performed to detect the expression of miRNA-221. Flow cytometry and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-digoxigenin nick-end labeling (TUNEL) staining were used to detect cell apoptosis. The immunofluorescence method was also used to detect cell signal transduction and activator of transcription 3 (Stat3) protein expression distribution. In addition, Western blotting was used to detect changes in the expression of each protein. We found that miRNA-221 was upregulated in Saos-2/DOX cells. Moreover, the miRNA-221 mimic induced DOX resistance in Saos-2 cells, whereas the miRNA-221 inhibitor enhanced DOX sensitivity in Saos-2/DOX cells. The miRNA-221 mimic upregulated the expression of phosphorylated-Stat3, P-glycoprotein (P-gp), and B-cell lymphoma-2 (Bcl-2) proteins in Saos-2 cells and induced the entry of Stat3 into the nucleus, whereas the miRNA-221 inhibitor exerted the opposite effect. Pretreatment with the Stat3 chemical inhibitor, STAT3-IN-3, significantly inhibited the upregulation of P-gp and Bcl-2 protein expression induced by the miRNA-221 mimic in Saos-2 cells; it also caused the Saos-2 cells to overcome DOX resistance induced by the miRNA-221 mimic. Thus, miRNA-221 increased the expression of P-gp and Bcl-2 by activating the Stat3 pathway to promote DOX resistance in osteosarcoma cells, indicating a potential use of miRNA-221 in osteosarcoma treatment.

Reviewing the mechanisms of natural product-drug interactions involving efflux transporters and metabolic enzymes

The World Health Organization (WHO) and other worldwide health agencies have recently taken initiatives to encourage the use of traditional medicine and/or complementary/alternative medicine in order to promote well-being and public health. In this way, one of the WHO's concerns is the safe use of these therapies. Phytotherapy is a strategy consisting of the use of medicinal plants (MP) and/or herbal medicinal products (HMP) for medicinal purposes. The use of phytotherapy concomitantly with drugs may cause interactions compromising the expected pharmacological action or generating toxic effects. These interactions are complex processes that may occur with multiple medications targeting different metabolic pathways, and involving different compounds present in MP and HMP. Thus, the aim of this review was to summarize the main MP- and HMP-drug interactions that involve specific transporters (P-glycoprotein and BCRP) and CYP450 enzymes (CYP3A4 and CYP2D6), which play relevant roles in the mechanisms of interactions. Firstly, multiple databases were used to search studies describing in vitro or in vivo MP and HMP-drug interactions and, after that, a systematic note-taking and appraisal of the literature was conducted. It was observed that several MP and HMP, metabolic pathways and transcription factors are involved in the transporters and enzymes expression or in the modulation of their activity having the potential to provide such interactions. Thus, the knowledge of MP- and HMP-drug interaction mechanisms could contribute to prevent harmful interactions and can ensure the safe use of these products to help the establishment of the therapeutic planning in order to certify the best treatment strategy to be used.

Chrysosplenetin promotes osteoblastogenesis of bone marrow stromal cells via Wnt/β-catenin pathway and enhances osteogenesis in estrogen deficiency-induced bone loss

BACKGROUND

Chrysosplenetin is an O-methylated flavonol compound isolated from the plant Chamomilla recutita and Laggera pterodonta. The aim of our research is to evaluate the function of Chrysosplenetin on osteogenesis of human-derived bone marrow stromal cells (hBMSCs) and inhibition of estrogen deficiency-induced osteoporosis via the Wnt/β-catenin signaling pathway.

METHOD

hBMSCs are cultured and treated by Chrysosplenetin in the absence or presence of Wnt inhibitor dickkopf-related protein 1 (DKK1) or bone morphogenetic protein 2 (BMP2) antagonist Noggin. RT-qPCR is taken to identify the genetic expression of target genes of Wnt/β-catenin pathway and osteoblast-specific markers. The situation of β-catenin is measured by western blot and immunofluorescence staining. An ovariectomized (OVX) mouse model is set up to detect the bone loss suppression by injecting Chrysosplenetin. Micro-CT and histological assay are performed to evaluate the protection of bone matrix and osteoblast number. Serum markers related with osteogenesis are detected by ELISA.

RESULTS

In the present study, it is found that Chrysosplenetin time-dependently promoted proliferation and osteoblastogenesis of hBMSCs reaching its maximal effects at a concentration of 10 μM. The expressions of target genes of Wnt/β-catenin pathway and osteoblast-specific marker genes are enhanced by Chrysosplenetin treatment. Furthermore, the phosphorylation of β-catenin is decreased, and nuclear translocation of β-catenin is promoted by Chrysosplenetin. Osteogenesis effects mentioned above are founded to be blocked by DKK1 or BMP2 antagonist Noggin. In vivo study reveals that Chrysosplenetin prevents estrogen deficiency-induced bone loss in OVX mice detected by Micro-CT, histological analysis, and ELISA.

CONCLUSIONS

Our study demonstrates that Chrysosplenetin improves osteoblastogenesis of hBMSCs and osteogenesis in estrogen deficiency-induced bone loss by regulating Wnt/β-catenin pathway.

Interactions between artemisinin derivatives and P-glycoprotein

BACKGROUND

Artemisinin was isolated and identified in 1972, which was the starting point for a new era in antimalarial drug therapy. Furthermore, numerous studies have demonstrated that artemisinin and its derivatives exhibit considerable anticancer activity both in vitro, in vivo, and even in clinical Phase I/II trials. P-glycoprotein (P-gp) mediated multi-drug resistance (MDR) is one of the most serious causes of chemotherapy failure in cancer treatment. Interestingly, many artemisinin derivatives exhibit excellent ability to overcome P-gp mediated MDR and even show collateral sensitivity against MDR cancer cells. Furthermore, some artemisinin derivatives show P-gp-mediated MDR reversal activity. Therefore, the interaction between P-gp and artemisinin derivatives is important to develop novel combination treatment protocols with artemisinin derivatives and established anticancer drugs that are P-gp substrates.

PURPOSE

This systematic review provides an updated overview on the interaction between artemisinin derivatives and P-gp and the effect of artemisinin derivatives on the P-gp expression level.

RESULTS

Artemisinin derivatives exhibit multi-specific interactions with P-gp. The currently used artemisinin derivatives are not transported by P-gp. However, some of novel synthetized artemisinin derivatives exhibit P-gp substrate properties. Furthermore, many artemisinin derivatives act as P-gp inhibitors, which exhibit the potential to reverse MDR towards clinically used anticancer drugs.

CONCLUSION

Therefore, studies on the interaction between artemisinin derivatives and P-gp provide important information for the development of novel anti-cancer artemisinin derivatives to reverse P-gp mediated MDR and for the design of rational artemisinin-based combination therapies against cancer.

ABC Transporters in Extrahepatic Tissues: Pharmacological Regulation in Heart and Intestine

ATP binding cassette (ABC) transporters are transmembrane proteins expressed in secretory epithelia like the liver, kidneys and intestine, in the epithelia exhibiting barrier function such as the blood-brain barrier and placenta, and to a much lesser extent, in tissues like reproductive organs, lungs, heart and pancreas, among others. They regulate internal distribution of endogenous metabolites and xenobiotics including drugs of therapeutic use and also participate in their elimination from the body. We here describe the function and regulation of ABC transporters in the heart and small intestine, as examples of extrahepatic tissues, in which ABC proteins play clearly different roles. In the heart, they are involved in tissue pathogenesis as well as in protecting this organ against toxic compounds and druginduced oxidative stress. The small intestine is highly exposed to therapeutic drugs taken orally and, consequently, ABC transporters localized on its surface strongly influence drug absorption and pharmacokinetics. Examples of the ABC proteins currently described are Multidrug Resistance-associated Proteins 1 and 2 (MRP1 and 2) for heart and small intestine, respectively, and P-glycoprotein (P-gp) and Breast Cancer Resistance Protein (BCRP) for both organs.

Absorption Characteristics of Chitobiose and Chitopentaose in the Human Intestinal Cell Line Caco-2 and Everted Gut Sacs

The everted gut sacs and Caco-2 cell models were used to investigate the intestinal absorptive characteristics and subcellular localization of chitobiose and chitopentaose in this study. In everted gut sacs, the absorptive pattern showed no concentration-dependent manner when the concentration was lower than 10 mM. In the presence of phlorizin (100 μM) and phloretin (100 μM), the chitobiose absorption rates decreased by (4.97 ± 0.89)% and (19.2 ± 2.77)%, and they were (10.4 ± 2.43)% and (27.5 ± 1.68)% for chitopentaose. In Caco-2 cells, the concentration showed influences similar to those with the everted gut sacs results. After adding phlorizin and phloretin in the apical side, the P_appAP-BL of chitobiose and chitopentaose significantly decreased. Considering the translocation, they were enriched in endoplasmic reticulum and mitochondrion. This study indicated that concentration and active transporter were capable of mediating the absorption of chitobiose and chitopentaose, and the subcellular localization of them could help to study the mechanisms of their effects.

Inhibitory Effects of Benzaldehyde, Vanillin, Muscone and Borneol on P-Glycoprotein in Caco-2 Cells and Everted Gut Sac

Aims: In clinical practice, herbal medicines have played an important role in the modulation of drug transporters through the combination of conventional prescription drugs, which necessitates the elucidation of herb-drug interactions. The present study was designed to investigate the inhibitory effects and mechanisms of benzaldehyde, vanillin, muscone, and borneol on P-glycoprotein (P-gp). Methods: The effects of the 4 compounds on the intracellular accumulation of rhodamine-123 (Rho-123) in vinblastine-treated Caco-2 (VB-Caco-2) cells were studied by monitoring fluorescence intensity through a flow cytometry assay, and the effects of these compounds on Rho-123 transport through VB-Caco-2 monolayers and Rho-123 intestinal absorption in the rat everted gut sac were investigated by high-performance liquid chromatography. Moreover, P-gp expression in VB-Caco-2 cells was assessed using flow cytometry and Western blot analysis, and the relative ABCB1 mRNA level was determined by Real-time RT-PCR. Key Findings: The results showed that benzaldehyde, vanillin, muscone, and borneol significantly increased Rho-123 uptake in VB-Caco-2 cells, increased the absorption rate and apparent permeability coefficient of Rho-123 in rat jejunum and ileum, and decreased the efflux ratio of Rho-123 from 6.52 to less than 2 during transport across VB-Caco-2 cell monolayers. In addition, these compounds reduced the protein and ABCB1 mRNA levels of P-gp in VB-Caco-2 cells. Conclusions: These data indicate that benzaldehyde, vanillin, muscone and borneol could effectively reverse multidrug resistance via inhibiting the P-gp function and expression pathway. The data provide fodder for further investigation into the interaction between the 4 compounds and other drugs transported by P-gp.