Micheliolide, a new sesquiterpene lactone that inhibits intestinal inflammation and colitis-associated cancer

Mesenchymal Stromal Cells Directly Promote Inflammation by Canonical NLRP3 and Non-canonical Caspase-11 Inflammasomes

Mesenchymal stromal cells (MSCs) based therapy is a promising approach to treat inflammatory disorders. However, therapeutic effect is not always achieved. Thus the mechanism involved in inflammation requires further elucidation. To explore the mechanisms by which MSCs respond to inflammatory stimuli, we investigated whether MSCs employed inflammasomes to participate in inflammation. Using in vitro and in vivo models, we found that canonical NLRP3 and non-canonical caspase-11 inflammasomes were activated in bone-associated MSCs (BA-MSCs) to promote the inflammatory response. The NLRP3 inflammasome was activated to mainly elicit IL-1β/18 release, whereas the caspase-11 inflammasome managed pyroptosis. Furthermore, we sought a small molecule component (66PR) to inhibit the activation of inflammasomes in BA-MSCs, which consequently improved their survival and therapeutic potential in inflammation bowel diseases. These current findings indicated that MSCs themselves could directly promote the inflammatory response by an inflammasome-dependent pathway. Our observations suggested that inhibition of the proinflammatory property may improve MSCs utilization in inflammatory disorders.

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NLRP3 and caspase-11 inflammasomes were activated in bone associated MSCs after stimulation.

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NLRP3 inflammasome mainly secreted IL-1β/18, whereas caspase-11 inflammasome managed pyroptosis in bone associated MSCs.

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Inhibition of inflammasomes in bone associated MSCs benefits their utilization for inflammatory diseases therapy.

Abnormal inflammations cause currently high incidence of diseases worldwide, such as sepsis, allergic reactions, and even cancer. But the therapy of inflammatory diseases is far from satisfaction heretofore. MSCs are great interest to treat inflammatory disorders. However, many studies found their therapeutic effects were not always achieved. Further studies on the molecular mechanisms by which MSCs respond to the inflammatory microenvironment will undoubtedly promote applications in clinic. Here, we observed that MSCs promoted the inflammatory response by an inflammasome-dependent pathway. Regulation of this pathway improved MSCs to counter against inflammatory disorders.

Micheliolide alleviates hepatic steatosis in db/db mice by inhibiting inflammation and promoting autophagy via PPAR-γ-mediated NF-кB and AMPK/mTOR signaling

The anti-inflammatory, immunomodulatory, and anticancer effects of micheliolide (MCL) isolated from Michelia champaca were previously reported, but its role and underlying mechanisms in relieving liver steatosis remain unclear. Herein, we investigated the effects of MCL on hepatic steatosis using a db/db mouse model and lipid mixture (LM)-induced AML12 and LO2 cells. The body and liver weights, food consumption, lipid content and liver aminotransferase levels in serum, the lipid content and inflammatory cytokine levels in liver tissue, and the extent of hepatic steatosis in db/db mice were increased compared with those in db/m mice, and these increases were reversed by MCL treatment. Similarly, MCL also attenuated the inflammatory responses and lipid accumulation in LM-treated AML12 and L02 cells by upregulating PPAR-γ and decreasing p-IкBα and p-NF-κB/p65, thereby inhibiting the NF-κB pathway and reducing lipotoxicity. Furthermore, MCL administration increased LC3B, Atg7 and Beclin-1 expression and the LC3B-II/I ratio in db/db mouse livers and LM-treated AML12 and L02 cells, and these MCL-induced increases were mediated by the activation of PPAR-γ and p-AMPK and inhibition of p-mTOR and induce autophagy. These effects were blocked by PPAR-γ and AMPK inhibitors. Our findings suggest that MCL ameliorates liver steatosis by upregulating PPAR-γ expression, thereby inhibiting NF-κB-mediated inflammation and activating AMPK/mTOR-dependent autophagy.

Colon-targeted delivery of cyclosporine A using dual-functional Eudragit® FS30D/PLGA nanoparticles ameliorates murine experimental colitis

Background

Colon-targeted oral nanoparticles (NPs) have emerged as an ideal, safe, and effective therapy for ulcerative colitis (UC) owing to their ability to selectively accumulate in inflamed colonic mucosa. Cyclosporine A (CSA), an immunosuppressive agent, has long been used as rescue therapy in severe steroid-refractory UC. In this study, we developed CSA-loaded dual-functional polymeric NPs composed of Eudragit^® FS30D as a pH-sensitive polymer for targeted delivery to the inflamed colon, and poly(lactic-co-glycolic acid) (PLGA) as a sustained-release polymer.

Methods

CSA-loaded Eudragit FS30D nanoparticles (ENPs), PLGA nanoparticles (PNPs), and Eudragit FS30D/PLGA nanoparticles (E/PNPs) were prepared using the oil-in-water emulsion method. Scanning electron microscope images and zeta size data showed successful preparation of CSA-loaded NPs.

Results

PNPs exhibited a burst drug release of >60% at pH 1.2 (stomach pH) in 0.5 h, which can lead to unwanted systemic absorption and side effects. ENPs effectively inhibited the burst drug release at pH 1.2 and 6.8 (proximal small intestine pH); however, nearly 100% of the CSA in ENPs was released rapidly at pH 7.4 (ileum–colon pH) owing to complete NP dissolution. In contrast to single-functional PNPs and ENPs, the dual-functional E/PNPs minimized burst drug release (only 18%) at pH 1.2 and 6.8, and generated a sustained release at pH 7.4 thereafter. Importantly, in distribution studies in the gastrointestinal tracts of mice, E/PNPs significantly improved CSA distribution to the colon compared with PNPs or ENPs. In a mouse model of colitis, E/PNP treatment improved weight loss and colon length, and decreased rectal bleeding, spleen weight, histological scoring, myeloperoxidase activity, macrophage infiltration, and expression of proinflammatory cytokines compared with PNPs or ENPs.

Conclusion

Overall, this work confirms the benefits of CSA-loaded E/PNPs for efficiently delivering CSA to the colon, suggesting their potential for UC therapy.

Antineoplastic effects and mechanisms of micheliolide in acute myelogenous leukemia stem cells

Leukemic stem cells (LSCs) greatly contribute to the initiation, relapse, and multidrug resistance of leukemia. Current therapies targeting the cell cycle and rapidly growing leukemic cells, including conventional chemotherapy, have little effect due to the self-renewal and differentiated malignant cells replenishment ability of LSCs despite their scarce supply in the bone marrow. Micheliolide (MCL) is a natural guaianolide sesquiterpene lactone (GSL) which was discovered in michelia compressa and michelia champaca plants, and has been shown to exert selective cytotoxic effects on CD34⁺CD38⁻ LSCs. In this study, we demonstrate that DMAMCL significantly prolongs the lifespan of a mouse model of human acute myelogenous leukemia (AML). Mechanistic investigations further revealed that MCL exerted its cytotoxic effects via inhibition of NF-κB expression and activity, and by generating intracellular reactive oxygen species (ROS). These results provide valuable insight into the mechanisms underlying MCL-induced cytotoxicity of LSCs, and support further preclinical investigations of MCL-related therapies for the treatment of AML.

Micheliolide suppresses LPS-induced neuroinflammatory responses

Microglia-involved neuroinflammation is thought to promote brain damage in various neurodegenerative disorders. Thus, inhibition of microglial over-activation may have a therapeutic benefit for the treatment of neurodegenerative disorders. Micheliolide (MCL) is a sesquiterpene lactone which inhibits various inflammatory response. However, whether MCL can inhibit neuroinflammation caused by LPS-activated BV2 microglia has not yet been explored. In this study, we demonstrated that treatment of BV2 cells with MCL significantly repressed LPS-stimulated nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression, as well as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and nitric oxide (NO) induction. MCL also attenuated mRNA levels of multiple pro-inflammatory cytokines and mediators such as iNOS, COX-2, TNF-α, IL-6 and IL-1β. Mechanistic studies revealed that MCL suppressed LPS-stimulated the activation of IκBα/NF-κB pathway and Akt pathway. Moreover, MCL inhibited LPS-induced the activition of c-Jun N-terminal kinase (JNK), p38 MAPK kinase, and extracellular signal-regulated kinases 1/2 (ERK1/2). Meanwhile, MCL markedly promoted antioxidant protein heme oxygenase-1 (HO-1) expression by enhancing NF-E2-related factor 2 (Nrf2) activity. Together, our results imply that MCL may serve as a neuroprotective agent in neuroinflammation-related neurodegenerative disorders.

Engineered biomimetic nanovesicles show intrinsic anti-inflammatory properties for the treatment of inflammatory bowel diseases

Inflammatory bowel disease (IBD), which includes Crohn's disease and ulcerative colitis, is a chronic inflammatory condition of the gastrointestinal (GI) tract. Currently, it is treated with immunosuppressant or biologics that often induce severe adverse effects. Thus, there is an urgent clinical need for more specific treatments. To provide a valid therapeutic tool for IBD therapy, in this work we developed biomimetic nanovesicles by manipulating leukocyte membranes to exploit mechanisms of T-cell recruitment during inflammation. A subset of T-lymphocytes participates in homing to inflamed tissue in the gastrointestinal tract by overexpressing the α4β7 integrin, which is responsible for binding to its receptor on the endothelial membrane, the mucosal addressin cell adhesion molecule 1. Based on this principle, we engineered biomimetic vesicles, referred to as specialized leukosomes (SLKs), which are leukocyte-like carriers 'doped' with the α4β7 integrin over-induced in purified immune cells. We tested SLKs in an in vivo murine model of IBD induced by treatment with dextran sulfate sodium. Notably, treatment of IBD mice with SLKs allowed us to observe a reduction of inflammation (favorable modulation of both pro- and anti-inflammatory genes, as well as reduction of immune cells infiltration into the colon tissue), and a consequent enhanced intestinal repair (low epithelial damage). In this study, we demonstrate that biological-derived nanoparticles can be used not only as naturally targeted drug delivery systems, but also as nano-therapeutics endowed with intrinsic anti-inflammatory properties.

Sesquiterpene binding Gly-Leu-Ser/Lys-"co-adaptation pocket" to inhibit lung cancer cell epithelial-mesenchymal transition

Sesquiterpene lactones (SL) have a wide range of applications in anti-tumor and anti-inflammatory therapy. However, the pharmacological mechanism of such substances is not clear. In this study, parthenolide (PTL) was used as an example to explore the anti-tumor effect of natural molecules and their common mechanism. We showed that PTL inhibited the proliferation and migration by reverse EMT via the ERK2/NF-κB/Snail pathway in vivo and in vitro. Interestingly, Multiple potential targets of PTL contain a Gly-Leu-Ser/Lys-“co-adaptation pocket”. This inspiring us analogies of PTL may also bind to these target proteins and play a similar function. Significantly, the Concept of co-adaptation pocket may help to increase the selectivity of drug research and development.

iRGD-functionalized PEGylated nanoparticles for enhanced colon tumor accumulation and targeted drug delivery

AIM

To enhance the tumor accumulation and targeted drug delivery for colon cancer therapy, iRGD peptide was introduced to the surface of PEGylated camptothecin-loaded nanoparticles (NPs).

METHODS

Cellular uptake, targeting specificity, biodistribution and antitumor capacity were evaluated.

RESULTS

The functionalization of iRGD facilitated tumor accumulation and cellular uptake of NPs by Colon-26 cells. Furthermore, the resultant iRGD-PEG-NPs remarkably improved the therapeutic efficacy of camptothecin in vitro and in vivo by inducing a higher degree of tumor cell apoptosis compared with PEG-NPs.

CONCLUSION

iRGD-PEG-NP is a desired drug delivery system to facilitate the drug accumulation in orthotopic colon tumor tissues and further drug internalization by colon cancer cells.

Chemopreventive Strategies for Inflammation-Related Carcinogenesis: Current Status and Future Direction

A sustained and chronically-inflamed environment is characterized by the presence of heterogeneous inflammatory cellular components, including neutrophils, macrophages, lymphocytes and fibroblasts. These infiltrated cells produce growth stimulating mediators (inflammatory cytokines and growth factors), chemotactic factors (chemokines) and genotoxic substances (reactive oxygen species and nitrogen oxide) and induce DNA damage and methylation. Therefore, chronic inflammation serves as an intrinsic niche for carcinogenesis and tumor progression. In this article, we summarize the up-to-date findings regarding definitive/possible causes and mechanisms of inflammation-related carcinogenesis derived from experimental and clinical studies. We also propose 10 strategies, as well as candidate agents for the prevention of inflammation-related carcinogenesis.

Minimally invasive screening for colitis using attenuated total internal reflectance fourier transform infrared spectroscopy

This article describes a rapid, simple and cost-effective technique that could lead to a screening method for colitis without the need for biopsies or in vivo measurements. This screening technique includes the testing of serum using Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy for the colitis-induced increased presence of mannose. Chronic (Interleukin 10 knockout) and acute (Dextran Sodium Sulphate-induced) models for colitis are tested using the ATR-FTIR technique. Arthritis (Collagen Antibody Induced Arthritis) and metabolic syndrome (Toll like receptor 5 knockout) models are also tested as controls. The marker identified as mannose uniquely screens and distinguishes the colitic from the non-colitic samples and the controls. The reference or the baseline spectrum could be the pooled and averaged spectra of non-colitic samples or the subject's previous sample spectrum. This shows the potential of having individualized route maps of disease status, leading to personalized diagnosis and drug management.

Micheliolide provides protection of mice against Staphylococcus aureus and MRSA infection by down-regulating inflammatory response

A major obstacle to therapy in intensive care units is sepsis caused by severe infection. In recent years gram-positive (G⁺) bacteria, most commonly staphylococci, are thought to be the main pathogens. Micheliolide (MCL) was demonstrated to provide a therapeutic role in rheumatoid arthritis, inflammatory intestinal disease, colitis-associated cancer, and lipopolysaccharide (LPS, the main component of G⁻ bacterial cell wall) induced septic shock. We proved here that MCL played an anti-inflammatory role in Staphylococcus aureus (S. aureus) and methicillin-resistant S. aureus (MRSA) induced peritonitis. It inhibited the expression of inflammatory cytokines and chemokines in macrophages and dendritic cells upon stimulation with peptidoglycan (PGN, the main cell wall composition of G⁺ bacteria). PI3K/Akt and NF-κB pathways account for the anti-inflammatory role of MCL after PGN stimulation. MCL reduced IL-6 secretion through down-regulating NF-κB activation and improved the survival status in mice challenged with a lethal dose of S. aureus. In MRSA infection mouse model, MCL down-regulated the expression of IL-6, TNF-α, MCP-1/CCL2 and IFN-γ in sera, and ameliorated the organ damage of liver and kidney. In conclusion, MCL can help maintain immune equilibrium and decrease PGN, S. aureus and MRSA-triggered inflammatory response. These provide the rationality for the potential usage of MCL in sepsis caused by G⁺ bacteria (e.g., S. aureus) and antibiotic-resistant bacteria (e.g., MRSA).

Edible ginger-derived nanoparticles: A novel therapeutic approach for the prevention and treatment of inflammatory bowel disease and colitis-associated cancer

There is a clinical need for new, more effective treatments for chronic and debilitating inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis. In this study, we characterized a specific population of nanoparticles derived from edible ginger (GDNPs 2) and demonstrated their efficient colon targeting following oral administration. GDNPs 2 had an average size of ∼230 nm and exhibited a negative zeta potential. These nanoparticles contained high levels of lipids, a few proteins, ∼125 microRNAs (miRNAs), and large amounts of ginger bioactive constituents (6-gingerol and 6-shogaol). We also demonstrated that GDNPs 2 were mainly taken up by intestinal epithelial cells (IECs) and macrophages, and were nontoxic. Using different mouse colitis models, we showed that GDNPs 2 reduced acute colitis, enhanced intestinal repair, and prevented chronic colitis and colitis-associated cancer (CAC). 2D-DIGE/MS analyses further identified molecular target candidates of GDNPs 2 involved in these mouse models. Oral administration of GDNPs 2 increased the survival and proliferation of IECs and reduced the pro-inflammatory cytokines (TNF-α, IL-6 and IL-1β), and increased the anti-inflammatory cytokines (IL-10 and IL-22) in colitis models, suggesting that GDNPs 2 has the potential to attenuate damaging factors while promoting the healing effect. In conclusion, GDNPs 2, nanoparticles derived from edible ginger, represent a novel, natural delivery mechanism for improving IBD prevention and treatment with an added benefit of overcoming limitations such as potential toxicity and limited production scale that are common with synthetic nanoparticles.

Cyclopropanyldehydrocostunolide LJ attenuates high glucose-induced podocyte injury by suppressing RANKL/RANK-mediated NF-κB and MAPK signaling pathways

AIMS

The aim of this research was to investigate the effects of cyclopropanyldehydrocostunolide (also named LJ), a derivative of sesquiterpene lactones (SLs), on high glucose (HG)-induced podocyte injury and the associated molecular mechanisms.

METHODS

Differentiated mouse podocytes were incubated in different treatments. The migration and albumin filtration of podocytes were examined by Transwell filters. The protein and mRNA levels of MCP-1 were measured using enzyme-linked immunosorbent assay (ELISA) and quantitative real-time PCR (q-PCR). Protein expression and phosphorylation were detected by western blot, and the nuclear translocation of NF-κB was performed with a confocal microscope. The gene expression of the receptor activator for NF-κB (RANK) was silenced by small interfering RNA (siRNA).

RESULTS

Our results showed that HG enhanced migration, albumin filtration and MCP-1 expression in podocytes. At the molecular level, HG promoted the phosphorylation of NF-κB/p65, IKKβ, IκBα, mitogen-activated protein kinase (MAPK) and the nuclear translocation of p65. LJ reversed the effects of HG in a dose-dependent manner. Furthermore, our data provided the first demonstration that the receptor activator for NF-κB ligand (RANKL) and its cognate receptor RANK were overexpressed in HG-induced podocytes and were downregulated by LJ. RANK siRNA also attenuated HG-induced podocyte injury and markedly inhibited the activation of NF-κB and MAPK signaling pathways.

CONCLUSIONS

LJ attenuates HG-induced podocyte injury by suppressing RANKL/RANK-mediated NF-κB and MAPK signaling pathways.

Micheliolide inhibits LPS-induced inflammatory response and protects mice from LPS challenge

Sepsis is the principal cause of fatality in the intensive care units worldwide. It involves uncontrolled inflammatory response resulting in multi-organ failure and even death. Micheliolide (MCL), a sesquiterpene lactone, was reported to inhibit dextran sodium sulphate (DSS)-induced inflammatory intestinal disease, colitis-associated cancer and rheumatic arthritis. Nevertheless, the role of MCL in microbial infection and sepsis is unclear. We demonstrated that MCL decreased lipopolysaccharide (LPS, the main cell wall component of Gram-negative bacteria)-mediated production of cytokines (IL-6, TNF-α, MCP-1, etc) in Raw264.7 cells, primary macrophages, dendritic cells and human monocytes. MCL plays an anti-inflammatory role by inhibiting LPS-induced activation of NF-κB and PI3K/Akt/p70S6K pathways. It has negligible impact on the activation of mitogen-activated protein kinase (MAPK) pathways. In the acute peritonitis mouse model, MCL reduced the secretion of IL-6, TNF-α, IL-1β, MCP-1, IFN-β and IL-10 in sera, and ameliorated lung and liver damage. MCL down-regulated the high mortality rate caused by lethal LPS challenge. Collectively, our data illustrated that MCL enabled maintenance of immune equilibrium may represent a potentially new anti-inflammatory and immunosuppressive drug candidate in the treatment of sepsis and septic shock.

Critical role of PepT1 in promoting colitis-associated cancer and therapeutic benefits of the anti-inflammatory PepT1-mediated tripeptide KPV in a murine model

BACKGROUND AND AIMS

The human intestinal peptide transporter 1, hPepT1, is expressed in the small intestine at low levels in the healthy colon and upregulated during inflammatory bowel disease. hPepT1 plays a role in mouse colitis and human studies have demonstrated that chronic intestinal inflammation leads to colorectal cancer (colitis-associated cancer; CAC). Hence, we assessed here the role of PepT1 in CAC.

METHODS

Mice with hPepT1 overexpression in intestinal epithelial cells (TG) or PepT1 (PepT1-KO) deletion were used and CAC was induced by AOM/DSS.

RESULTS

TG mice had larger tumor sizes, increased tumor burdens, and increased intestinal inflammation compared to WT mice. Conversely, tumor number and size and intestinal inflammation were significantly decreased in PepT1-KO mice. Proliferating crypt cells were increased in TG mice and decreased in PepT1-KO mice. Analysis of human colonic biopsies revealed an increased expression of PepT1 in patients with colorectal cancer, suggesting that PepT1 might be targeted for the treatment of CAC. The use of an anti-inflammatory tripeptide KPV (Lys-Pro-Val) transported by PepT1 was able to prevent carcinogenesis in WT mice. When administered to PepT1-KO mice, KPV did not trigger any of the inhibitory effect on tumorigenesis observed in WT mice.

CONCLUSIONS

The observations that pepT1 was highly expressed in human colorectal tumor and that its overexpression and deletion in mice increased and decreased colitis associated tumorigenesis, respectively, suggest that PepT1 is a potential therapeutic target for the treatment of colitis associated tumorigenesis.

Mechanistic roles of epithelial and immune cell signaling during the development of colitis-associated cancer

To date, substantial evidence has shown a significant association between inflammatory bowel diseases (IBD) and development of colitis-associated cancer (CAC). The incidence/prevalence of IBD is higher in western countries including the US, Australia, and the UK. Although CAC development is generally characterized by stepwise accumulation of genetic as well as epigenetic changes, precise mechanisms of how chronic inflammation leads to the development of CAC are largely unknown. Preceding intestinal inflammation is one of the major influential factors for CAC tumorigenesis. Mucosal immune responses including activation of aberrant signaling pathways both in innate and adaptive immune cells play a pivotal role in CAC. Tumor progression and metastasis are shaped by a tightly controlled tumor microenvironment which is orchestrated by several immune cells and stromal cells including macrophages, neutrophils, dendritic cells, myeloid derived suppressor cells, T cells, and myofibroblasts. In this article, we will discuss the contributing factors of epithelial as well as immune cell signaling in initiation of CAC tumorigenesis and mucosal immune regulatory factors in the colonic tumor microenvironment. In depth understanding of these factors is necessary to develop novel anti-inflammatory and anti-cancer therapies for CAC in the near future.

Dynamin-related protein 1 is involved in micheliolide-induced breast cancer cell death

Dynamin-related protein 1 (Drp1) is a newly discovered therapeutic target for tumor initiation, migration, proliferation, and chemosensitivity. Thus, therapeutic strategies that focus on targeting Drp1 and its related signaling pathway pave a new way to address the ineffectiveness of traditional cancer therapies. Micheliolide (MCL), a guaianolide sesquiterpene lactone, can selectively eradicate acute myeloid leukemia stem or progenitor cells. But the effect of MCL on the mitochondrial dynamics of cancer cells is still not well demonstrated. In this study, we show that MCL inhibited the growth of MCF-7 human breast cancer cells, accompanied by increased mitochondrial fission and upregulation of Drp1. The results obtained from overexpression experiments of wild or dominant-negative mutant type of Drp1 demonstrate that Drp1 is both necessary and sufficient to induce MDA-MB-231 and MCF-7 cell death. Furthermore, mitochondrial membrane potential decreased, whereas reactive oxygen species (ROS) generation, cytochrome c release, and PARP cleavage were enhanced after overexpression of Drp1 wild type. On the other hand, overexpression of Drp1-K38A (a dominant-negative mutant of Drp1) rescued cells from increased apoptosis, confirming the role of MCL-induced Drp1 in the observed apoptosis. Finally, MCL-induced Drp1-mediated cell death could be reversed by N-acetyl-L-cysteine (the ROS scavenger) in breast cancer cells. Taken together, the present study shows a novel role for Drp1 in MCL-induced breast cancer cell death, potentially through regulation of ROS–mitochondrial apoptotic pathway.

Hyaluronic acid-functionalized polymeric nanoparticles for colon cancer-targeted combination chemotherapy

Nanoparticle (NP)-based combination chemotherapy has been proposed as an effective strategy for achieving synergistic effects and targeted drug delivery for colon cancer therapy. Here, we fabricated a series of hyaluronic acid (HA)-functionalized camptothecin (CPT)/curcumin (CUR)-loaded polymeric NPs (HA-CPT/CUR-NPs) with various weight ratios of CPT to CUR (1 : 1, 2 : 1 and 4 : 1). The resultant spherical HA-CPT/CUR-NPs had a desirable particle size (around 289 nm), relative narrow size distribution, and slightly negative zeta potential. These NPs exhibited a simultaneous sustained release profile for both drugs throughout the time frame examined. Subsequent cellular uptake experiments demonstrated that the introduction of HA to the NP surface endowed NPs with colon cancer-targeting capability and markedly increased cellular uptake efficiency compared with chitosan-coated NPs. Importantly, the combined delivery of CPT and CUR in one HA-functionalized NP exerted strong synergistic effects. HA-CPT/CUR-NP (1 : 1) showed the highest antitumor activity among the three HA-CPT/CUR-NPs, resulting in an extremely low combination index. Collectively, our findings indicate that this HA-CPT/CUR-NP can be exploited as an efficient formulation for colon cancer-targeted combination chemotherapy.

Fisetin, a dietary flavonoid, ameliorates experimental colitis in mice: Relevance of NF-κB signaling

Fisetin, a dietary flavonoid, is commonly found in many fruits and vegetables. Although studies indicate that fisetin has an anti-inflammatory property, little is known about its effects on intestinal inflammation. The present study investigated the effects of the fisetin on dextran sulphate sodium (DSS)-induced murine colitis, an animal model that resembles human inflammatory bowel disease. Fisetin treatment to DSS-exposed mice significantly reduced the severity of colitis and alleviated the macroscopic and microscopic signs of the disease. Moreover, fisetin reduced the levels of myeloperoxidase activity, the production of proinflammatory cytokines, tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and interleukin-6 (IL-6) and the expressions of COX-2 and iNOS in the colon tissues. Further studies revealed that fisetin suppressed the activation of NF-κB (p65) by inhibiting IκBα phosphorylation and NF-κB (p65)-DNA binding activity and attenuated the phosphorylation of Akt and the p38, but not ERK and JNK MAPKs in the colon tissues of DSS-exposed mice. In addition, DSS-induced decline in reduced glutathione (GSH) and the increase in malondialdehyde (MDA) levels were significantly restored by oral fisetin. Furthermore, the results from in vitro studies showed that fisetin significantly reduced the pro-inflammatory cytokine and mediator release and suppressed the degradation and phosphorylation of IκBα with subsequent nuclear translocation of NF-κB (p65) in lipopolysaccharide (LPS)-stimulated mouse primary peritoneal macrophages. These results suggest that fisetin exerts anti-inflammatory activity via inhibition of Akt, p38 MAPK and NF-κB signaling in the colon tissues of DSS-exposed mice. Thus, fisetin may be a promising candidate as pharmaceuticals or nutraceuticals in the treatment of inflammatory bowel disease.