Curcumin analogue identified as hyaluronan export inhibitor by virtual docking to the ABC transporter MRP5

Geographical Discrimination of Curcuma longa L. in Vietnam Based on LC-HRMS Metabolomics

Curcuma longa L. has been used as a food, cosmetic, traditional medicine, and natural dye for a long time in tropical and subtropical regions such as India, China, and Vietnam. Curcuminoids are considered the main bioactive compounds in this plant. This study focuses on metabolites profiling of the rhizome methanolic extract of C longa samples collected in 6 different provinces in Vietnam using liquid chromatography coupled with high-resolution mass spectrometry. The partial least-squares discriminant analysis model was then established to discriminate its metabolomes and identify the chemomarkers that help to distinguish C longa from 6 geographical locations. Consequently, collected samples were segregated into 3 main groups: northern (Lang Son, with typical content of 2 terpenoids), center (Nghe An), and southern highland (Lam Dong, with distinctive profile of 3 curcuminoids). The absolute curcuminoids’ amount was also measured based on the calibration curve of reference standards. The differential metabolites including curcumin, demethoxycurcumin, and bisdemethoxycurcumin were found with the highest range in samples from Lang Son, indicating the excellent quality of turmeric cultivated in this area.

Inhibition of hyaluronan secretion by novel coumarin compounds and chitin synthesis inhibitors

Elevated plasma levels of hyaluronic acid (HA) is a disease marker in liver pathology and other inflammatory disorders. Inhibition of HA synthesis with coumarin 4-methylumbelliferone (4MU) has a beneficial effect in animal models of fibrosis, inflammation, cancer and metabolic syndrome. 4MU is an active compound of approved choleretic drug hymecromone with low bioavailability and a broad spectrum of action. New, more specific and efficient inhibitors of hyaluronan synthases (HAS) are required. We have tested several newly synthesized coumarin compounds and commercial chitin synthesis inhibitors to inhibit HA production in cell culture assay. Coumarin derivative compound VII (10'-methyl-6'-phenyl-3'H-spiro[piperidine-4,2'-pyrano[3,2-g]chromene]-4',8'-dione) demonstrated inhibition of HA secretion by NIH3T3 cells with the half-maximal inhibitory concentration (IC50) = 1.69 ± 0.75 μΜ superior to 4MU (IC50 = 8.68 ± 1.6 μΜ). Inhibitors of chitin synthesis, etoxazole, buprofezin, triflumuron, reduced HA deposition with IC50 of 4.21 ± 3.82 μΜ, 1.24 ± 0.87 μΜ and 1.48 ± 1.44 μΜ, respectively. Etoxazole reduced HA production and prevented collagen fibre formation in the CCl4 liver fibrosis model in mice similar to 4MU. Bioinformatics analysis revealed homology between chitin synthases and HAS enzymes, particularly in the pore-forming domain, containing the proposed site for etoxazole binding.

Discrimination of turmeric from different origins in China by MRM-based curcuminoid profiling and multivariate analysis

In this research, a three-step strategy was utilized for discriminating turmeric samples from different provinces and regions in China. Firstly, MRM-based UPLC-MS/MS method for chemical profiling of curcuminoids in turmeric samples was established. Then, response surface methodology was applied for optimizing the extraction process of targeted curcuminoids. Finally, multivariate analysis was conducted for systematic characterization of 66 curcuminoids in turmeric. Principal component analysis (PCA) and orthogonal projection to latent structure-discriminant analysis (OPLS-DA) revealed that turmeric samples from Sichuan and other regions could be classified into two distinct groups. Turmeric samples from the same group had similar curcuminoids content distribution. 25 differential curcuminoids were discovered through OPLS-DA, among which most curcuminoids were more abundant in Sichuan. Furthermore, turmeric samples from different provinces could be clearly discriminated based on hierarchical cluster analysis (HCA) using the screened differential curcuminoids.

Curcumin reverses doxorubicin resistance via inhibition the efflux function of ABCB4 in doxorubicin‑resistant breast cancer cells

Doxorubicin is one of the most widely used chemotherapy agents for the treatment of breast cancer. However, the development of doxorubicin resistance limits the long-term treatment benefits in patients with breast cancer. Curcumin, a well-known dietary polyphenol derived from the rhizomes of turmeric (Curcuma longa), enhances the sensitivity of breast cancer cells to chemotherapeutic agents; however, the mechanisms underlying this phenomenon remain unclear. The aim of the present study was to evaluate the effect of curcumin on chemoresistance in doxorubicin-resistant breast cancerMCF-7/DOX and MDA-MB-231/DOX cell lines. Cell Counting Kit-8, monolayer transport, western blot and ATPase activity assays were performed during the study. The results revealed that curcumin significantly enhanced the effect of doxorubicin in doxorubicin-resistant breast cancer cells. The intracellular accumulation of doxorubicin was substantially increased following curcumin treatment in doxorubicin-resistant breast cancer cells, in a manner that was inversely dependent on the activity of ATP binding cassette subfamily B member 4 (ABCB4). Treatment with a combination of curcumin and doxorubicin decreases the efflux of doxorubicin in ABCB4-overexpressing cells. Furthermore, curcumin inhibited the ATPase activity of ABCB4 without altering its protein expression. In conclusion, curcumin reversed doxorubicin resistance in human breast cancer MCF-7/DOX and MDA-MB-231/DOX cells by inhibiting the ATPase activity of ABCB4. The study highlights the promising use of curcumin as a chemosensitizer in the treatment of breast cancer.

Discovery of novel multidrug resistance protein 4 (MRP4) inhibitors as active agents reducing resistance to anticancer drug 6-Mercaptopurine (6-MP) by structure and ligand-based virtual screening

Multidrug resistance protein 4 (MRP4/ABCC4) is an ATP-binding cassette (ABC) transporter. It is associated with multidrug resistance (MDR), which is becoming a growing challenge to the treatment of cancer and infections. In the context of several types of cancer in which MRP4 is overexpressed, MRP4 inhibition manifests striking effects against cancer progression and drug resistance. In this study, we combined ligand-based and structure-based drug design strategy, by searching the SPECS chemical library to find compounds that are most likely to bind to MRP4. Clustering analysis based on a two-dimensional fingerprint was performed to help with visual selection of potential compounds. Cell viability assays with potential inhibitors and the anticancer drug 6-MP were carried out to identify their bioactivity. As a result, 39 compounds were tested and seven of them reached inhibition above 55% with 6-MP. Then compound Cpd23 was discovered to improve HEK293/MRP4 cell sensibility to 6-MP dramatically, and low concentration Cpd23 (5 μM) achieved the equivalent effect of 50 μM MK571. The accumulation of 6-MP was determined by validated high-performance liquid chromatography methods, and pretreatment of the HEK293/MRP4 cells with 50 μM MK571 or Cpd23 resulted in significantly increased accumulation of 6-MP by approximately 1.5 times. This compound was first reported with a novel scaffold compared with previously known MRP4 inhibitors, which is a hopeful molecular tool that can be used for overcoming multidrug resistance research.

The Effects of Synthetically Modified Natural Compounds on ABC Transporters

Multidrug resistance (MDR) is a major hurdle which must be overcome to effectively treat cancer. ATP-binding cassette transporters (ABC transporters) play pivotal roles in drug absorption and disposition, and overexpression of ABC transporters has been shown to attenuate cellular/tissue drug accumulation and thus increase MDR across a variety of cancers. Overcoming MDR is one desired approach to improving the survival rate of patients. To date, a number of modulators have been identified which block the function and/or decrease the expression of ABC transporters, thereby restoring the efficacy of a range of anticancer drugs. However, clinical MDR reversal agents have thus far proven ineffective and/or toxic. The need for new, effective, well-tolerated and nontoxic compounds has led to the development of natural compounds and their derivatives to ameliorate MDR. This review evaluates whether synthetically modifying natural compounds is a viable strategy to generate potent, nontoxic, ABC transporter inhibitors which may potentially reverse MDR.

Hyaluronan-mediated mononuclear leukocyte binding to gingival fibroblasts

OBJECTIVES

Binding of mononuclear leukocytes to hyaluronan cable structures is a well-known pathomechanism in several chronic inflammatory diseases, but has not yet described for chronic oral inflammations. The aim of this study was to evaluate if and how binding of mononuclear leukocytes to pathologic hyaluronan cable structures can be induced in human gingival fibroblasts.

MATERIAL AND METHODS

Experiments were performed with human gingival fibroblasts and peripheral blood mononuclear cells (PBMCs) from three healthy blood donors. Gingival fibroblasts were stimulated with (1) tunicamycin, (2) polyinosinic/polycytidylic acid (Poly:IC), and (3) lipopolysaccharides (LPS) to simulate (1) ER stress and (2) viral and (3) bacterial infections, respectively. Fibroblasts were then co-incubated with PBMCs, and the number of bound and fluorescently labeled PBMCs was assessed using a fluorescence reader and microscopy. For data analysis, a linear mixed model was used.

RESULTS

Hyaluronan-mediated binding of PBMCs to gingival fibroblasts was increased by tunicamycin and Poly(I:C) but not by LPS. Hyaluronidase treatment and co-incubation with hyaluronan transport inhibitors reduced this binding.

CONCLUSIONS

Results suggest that hyaluronan-mediated binding of blood cells might play a role in oral inflammations. A potential superior role of viruses needs to be confirmed in further clinical studies.

CLINICAL RELEVANCE

The linkage between pathological hyaluronan matrices and oral infections opens up potential applications of hyaluronan transport inhibitors in the treatment of chronic oral inflammations.

Dietary flavonoid fisetin increases abundance of high-molecular-mass hyaluronan conferring resistance to prostate oncogenesis

We and others have shown previously that fisetin, a plant flavonoid, has therapeutic potential against many cancer types. Here, we examined the probable mechanism of its action in prostate cancer (PCa) using a global metabolomics approach. HPLC-ESI-MS analysis of tumor xenografts from fisetin-treated animals identified several metabolic targets with hyaluronan (HA) as the most affected. Efficacy of fisetin on HA was then evaluated in vitro and also in vivo in the transgenic TRAMP mouse model of PCa. Size exclusion chromatography-multiangle laser light scattering (SEC-MALS) was performed to analyze the molar mass (Mw) distribution of HA. Fisetin treatment downregulated intracellular and secreted HA levels both in vitro and in vivo Fisetin inhibited HA synthesis and degradation enzymes, which led to cessation of HA synthesis and also repressed the degradation of the available high-molecular-mass (HMM)-HA. SEC-MALS analysis of intact HA fragment size revealed that cells and animals have more abundance of HMM-HA and less of low-molecular-mass (LMM)-HA upon fisetin treatment. Elevated HA levels have been shown to be associated with disease progression in certain cancer types. Biological responses triggered by HA mainly depend on the HA polymer length where HMM-HA represses mitogenic signaling and has anti-inflammatory properties whereas LMM-HA promotes proliferation and inflammation. Similarly, Mw analysis of secreted HA fragment size revealed less HMM-HA is secreted that allowed more HMM-HA to be retained within the cells and tissues. Our findings establish that fisetin is an effective, non-toxic, potent HA synthesis inhibitor, which increases abundance of antiangiogenic HMM-HA and could be used for the management of PCa.

Targeting hyaluronic acid family for cancer chemoprevention and therapy

Hyaluronic acid or hyaluronan (HA) is perhaps one of the most uncomplicated large polymers that regulates several normal physiological processes and, at the same time, contributes to the manifestation of a variety of chronic and acute diseases, including cancer. Members of the HA signaling pathway (HA synthases, HA receptors, and HYAL-1 hyaluronidase) have been experimentally shown to promote tumor growth, metastasis, and angiogenesis, and hence each of them is a potential target for cancer therapy. Furthermore, as these members are also overexpressed in a variety of carcinomas, targeting of the HA family is clinically relevant. A variety of targeted approaches have been developed to target various HA family members, including small-molecule inhibitors and antibody and vaccine therapies. These treatment approaches inhibit HA-mediated intracellular signaling that promotes tumor cell proliferation, motility, and invasion, as well as induction of endothelial cell functions. Being nontoxic, nonimmunogenic, and versatile for modifications, HA has been used in nanoparticle preparations for the targeted delivery of chemotherapy drugs and other anticancer compounds to tumor cells through interaction with cell-surface HA receptors. This review discusses basic and clinical translational aspects of targeting each HA family member and respective treatment approaches that have been described in the literature.

Dietary supplement 4-methylumbelliferone: an effective chemopreventive and therapeutic agent for prostate cancer

BACKGROUND

Prevention and treatment of advanced prostate cancer (PCa) by a nontoxic agent can improve outcome, while maintaining quality of life. 4-methylumbelliferone (4-MU) is a dietary supplement that inhibits hyaluronic acid (HA) synthesis. We evaluated the chemopreventive and therapeutic efficacy and mechanism of action of 4-MU.

METHODS

TRAMP mice (7-28 per group) were gavaged with 4-MU (450mg/kg/day) in a stage-specific treatment design (8-28, 12-28, 22-28 weeks). Efficacy of 4-MU (200-450mg/kg/day) was also evaluated in the PC3-ML/Luc(+) intracardiac injection and DU145 subcutaneous models. PCa cells and tissues were analyzed for HA and Phosphoinositide 3-kinase (PI-3K)/Akt signaling and apoptosis effectors. HA add-back and myristoylated Akt (mAkt) overexpression studies evaluated the mechanism of action of 4-MU. Data were analyzed with one-way analysis of variance and unpaired t test or Tukey's multiple comparison test. All statistical tests were two-sided.

RESULTS

While vehicle-treated transgenic adenocarcinoma of the prostate (TRAMP) mice developed prostate tumors and metastases at 28 weeks, both were abrogated in treatment groups, without serum/organ toxicity or weight loss; no tumors developed at one year, even after stopping the treatment at 28 weeks. 4-MU did not alter the transgene or neuroendocrine marker expression but downregulated HA levels. However, 4-MU decreased microvessel density and proliferative index (P < .0001,). 4-MU completely prevented/inhibited skeletal metastasis in the PC3-ML/Luc(+) model and DU145-tumor growth (85-90% inhibition, P = .002). 4-MU also statistically significantly downregulated HA receptors, PI-3K/CD44 complex and activity, Akt signaling, and β-catenin levels/activation, but upregulated GSK-3 function, E-cadherin, and apoptosis effectors (P < .001); HA addition or mAkt overexpression rescued these effects.

CONCLUSION

4-MU is an effective nontoxic, oral chemopreventive, and therapeutic agent that targets PCa development, growth, and metastasis by abrogating HA signaling.

Pharmacological profile of xanthohumol, a prenylated flavonoid from hops (Humulus lupulus)

The female inflorescences of hops (Humulus lupulus L.), a well-known bittering agent used in the brewing industry, have long been used in traditional medicines. Xanthohumol (XN) is one of the bioactive substances contributing to its medical applications. Among foodstuffs XN is found primarily in beer and its natural occurrence is surveyed. In recent years, XN has received much attention for its biological effects. The present review describes the pharmacological aspects of XN and summarizes the most interesting findings obtained in the preclinical research related to this compound, including the pharmacological activity, the pharmacokinetics, and the safety of XN. Furthermore, the potential use of XN as a food additive considering its many positive biological effects is discussed.

Heterocyclic cyclohexanone monocarbonyl analogs of curcumin can inhibit the activity of ATP-binding cassette transporters in cancer multidrug resistance

Curcumin (CUR) is a phytochemical that inhibits the xenobiotic ABC efflux transporters implicated in cancer multidrug resistance (MDR), such as P-glycoprotein (P-gp), breast cancer resistance protein (BCRP) and multidrug resistance-associated proteins 1 and 5 (MRP1 and MRP5). The use of CUR in the clinic however, is complicated by its instability and poor pharmacokinetic profile. Monocarbonyl analogs of CUR (MACs) are compounds without CUR's unstable β-diketone moiety and were reported to have improved stability and in vivo disposition. Whether the MACs can be used as MDR reversal agents is less clear, as the absence of a β-diketone may negatively impact transporter inhibition. In this study, we investigated 23 heterocyclic cyclohexanone MACs for inhibitory effects against P-gp, BCRP, MRP1 and MRP5. Using flow cytometry and resistance reversal assays, we found that many of these compounds inhibited the transport activity of the ABC transporters investigated, often with much greater potency than CUR. Overall the analogs were most effective at inhibiting BCRP and we identified three compounds, A12 (2,6-bis((E)-2,5-dimethoxy-benzylidene)cyclohexanone), A13 (2,6-bis((E)-4-hydroxyl-3-methoxybenzylidene)-cyclohexanone) and B11 (3,5-bis((E)-2-fluoro-4,5-dimethoxybenzylidene)-1-methylpiperidin-4-one), as the most promising BCRP inhibitors. These compounds inhibited BCRP activity in a non-cell line, non-substrate-specific manner. Their inhibition occurred by direct transporter interaction rather than modulating protein or cell surface expression. From these results, we concluded that MACs, such as the heterocyclic cyclohexanone analogs in this study, also have potential as MDR reversal agents and may be superior alternatives to the unstable parent compound, CUR.