Human Epithelial Colorectal Adenocarcinoma Cells Research Articles

Application of cold atmospheric pressure plasmas for high-throughput production of safe-to-consume beetroot juice with improved nutritional quality

A one-step, highly-efficiency, and low-cost cold atmospheric pressure plasma (CAPP)-based method for obtaining safe-to-consume beetroot juice (BRJ) with enhanced nutritional quality is presented. Three reaction-discharge systems with different CAPPs were studied to check how the composition and physicochemical properties changed during CAPP treatment of BRJ. To identify reactive species occur in gas phase of applied CAPP for BRJ treatment, optical emission spectrometry was used. Finally, the cytotoxicity of so-obtained BRJ to human epithelial colorectal adenocarcinoma (Caco-2) and human non-malignant intestine microvascular endothelial cells (HIMEC) was assessed. Based on the performed analyses it was found that controlled CAPP treatment of BRJ changes the fraction pattern of elements in addition to increase the content of phenolic compound presents in BRJ. Furthermore, the defined CAPP treatment of BRJ inhibits proliferation of Caco-2 cell lines, exhibiting non-cytotoxic effect for HIMEC non-malignant endothelial cells. As a result, safe-to-consume BRJ of improved nutritional quality was produced.

Selective Cytotoxic Activity of Prodigiosin@halloysite Nanoformulation.

Prodigiosin, a bioactive secondary metabolite produced by Serratia marcescens, is an effective proapoptotic agent against various cancer cell lines, with little or no toxicity toward normal cells. The hydrophobicity of prodigiosin limits its use for medical and biotechnological applications, these limitations, however, can be overcome by using nanoscale drug carriers, resulting in promising formulations for target delivery systems with great potential for anticancer therapy. Here we report on prodigiosin-loaded halloysite-based nanoformulation and its effects on viability of malignant and non-malignant cells. We have found that prodigiosin-loaded halloysite nanotubes inhibit human epithelial colorectal adenocarcinoma (Caco-2) and human colon carcinoma (HCT116) cells proliferative activity. After treatment of Caco-2 cells with prodigiosin-loaded halloysite nanotubes, we have observed a disorganization of the F-actin structure. Comparison of this effects on malignant (Caco-2, HCT116) and non-malignant (MSC, HSF) cells suggests the selective cytotoxic and genotoxic activity of prodigiosin-HNTs nanoformulation.

Functionalized Surface-Charged SiO2 Nanoparticles Induce Pro-Inflammatory Responses, but Are Not Lethal to Caco-2 Cells

Nanoparticles (NPs) are widely used in food, and analysis of their potential gastrointestinal toxicity is necessary. The present study was designed to determine the effects of silica dioxide (SiO2), titanium dioxide (TiO2), and zinc oxide (ZnO) NPs on cultured THP-1 monocyte-derived macrophages and human epithelial colorectal adenocarcinoma (Caco-2) cells. Exposure to ZnO NPs for 24 h increased the production of redox response species (ROS) and reduced cell viability in a dose-dependent manner in THP-1 macrophages and Caco-2 cells. Although TiO2 and SiO2 NPs induced oxidative stress, they showed no apparent cytotoxicity against both cell types. The effects of functionalized SiO2 NPs on undifferentiated and differentiated Caco-2 cells were investigated using fluorescently labeled SiO2 NPs with neutral, positive, or negative surface charge. Exposure of both types of cells to the three kinds of SiO2 NPs significantly increased their interaction in a dose-dependent manner. The largest interaction with both types of cells was noted with exposure to more negatively surface-charged SiO2 NPs. Exposure to either positively or negatively, but not neutrally, surface-charged SiO2 NPs increased NO levels in differentiated Caco-2 cells. Exposure of differentiated Caco-2 cells to positively or negatively surface-charged SiO2 NPs also upregulated interleukin-8 expression. We conclude that functionalized surface-charged SiO2 NPs can induce pro-inflammatory responses but are noncytotoxic.

Quinoisobutyride A, an acyclic antibacterial tetrapeptide incorporating an unprecedented heterocyclic amino acid residue from the hypersaline lake-derived fungus Penicillium simplicissimum strain WSH17

Chromatographic refining of the EtOAc extract of a solid rice culture of the hypersaline lake-derived fungus Penicillium simplicissimum strain WSH17 afforded a new linear antibacterial peptide quinoisobutyride A (1) along with three known metabolites (2-4). The chemical structure of 1 was unambiguously determined based on extensive 1D and 2D NMR spectroscopic analyses together with HRESIMS. In addition, Marfey’s derivatization method along with biogenetic considerations were used to determine the absolute configuration of its amino acids’ entities. Interestingly, in this study we distinguished a new unusual heterocyclic amino acid which is comprised as a unit of compound 1. Among the isolated compounds, only 1 revealed a promising antibacterial activity against Staphylococcus aureus (ATCC700699) with a MIC value of 2.72 μM (2.0 μg/mL). Moreover, citrinamide A (3) was the only isolated compound that showed a cytotoxic activity against human epithelial colorectal adenocarcinoma (Caco-2) cell line with an IC50 value of 12.76 μM (5.5 μg/mL).

Transformation of Psoralen and Isopsoralen by Human Intestinal Microbial In Vitro, and the Biological Activities of Its Metabolites.

Psoralen (P) and isopsoralen (IP) are the main active ingredients in the dried fruit of Psoralen corylifolia L. (PC), with a wide range of pharmacology activities. The intestinal bacteria biotransformation plays a central role in the metabolism of the complex ingredients in traditional Chinese medicine (TCM). Our study aimed to investigated the metabolic profile of P and IP in the intestinal condition, co-cultured with human fecal bacteria anaerobically. Four bio-transforming products were obtained, including 6,7-furano-hydrocoumaric acid (P-1) and 6,7-furano-hydro- coumaric acid methyl ester (P-2), which transformed from P, and 5,6-furano-hydrocoumaric acid (IP-1) and 5,6-furano-hydrocoumaric acid methyl ester (IP-2), which were transformed from IP. It is worth mentioning that IP-2 is a new compound that has not been published. Their structures were analyzed based on their spectroscopic data. Moreover, a highly sensitive ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was used to characterize the metabolic pathways of P, IP, and their bio-transforming products in the reaction samples. In addition, the dampening effects against the oxidative stress of P, IP, and their bio-transforming products by human intestinal flora were estimated in vitro via the human colorectal cells (HCT116) and heterogeneous human epithelial colorectal adenocarcinoma cells (Caco-2) cell lines. The results showed that the metabolites have stronger activity than P and IP, which possibly provides a basis for elucidating the treating mechanisms of PC extract against inflammatory bowel disease.

In Vitro Cytotoxicity of Oleanolic/Ursolic Acids-Loaded in PLGA Nanoparticles in Different Cell Lines.

Oleanolic (OA) and ursolic (UA) acids are recognized triterpenoids with anti-cancer properties, showing cell-specific activity that can be enhanced when loaded into polymeric nanoparticles. The cytotoxic activity of OA and UA was assessed by Alamar Blue assay in three different cell lines, i.e., HepG2 (Human hepatoma cell line), Caco-2 (Human epithelial colorectal adenocarcinoma cell line) and Y-79 (Human retinoblastoma cell line). The natural and synthetic mixtures of these compounds were tested as free and loaded in polymeric nanoparticles in a concentration range from 2 to 32 µmol/L. The highest tested concentrations of the free triterpene mixtures produced statistically significant cell viability reduction in HepG2 and Caco-2 cells, compared to the control (untreated cells). When loaded in the developed PLGA nanoparticles, no differences were recorded for the tested concentrations in the same cell lines. However, in the Y-79 cell line, a decrease on cell viability was observed when testing the lowest concentration of both free triterpene mixtures, and after their loading into PLGA nanoparticles.

In vitro evaluation of tumor targeting ability of a parenteral enoxaparin-coated self-emulsifying drug delivery system

Enoxaparin (Enox) has been previously proposed as targeting ligands for tumor, due to the binding of the extracellular tumor matrix (ECM)components overexpressed in tumor tissues. Thus, in the present work we investigated the possibility to develop a parenteral Enox-coated self-emulsifying drug delivery system (SEDDS) for tumor targeting. Enox was chemically conjugated to palmitoyl chloride (PC) and then used to coat SEDDS. The formulations exhibited a size of 91–102 nm, and showed good stability in serum albumin and in plasma. Moreover, negligible hemolytic activity was found in the case of SEDDS and Enox-coated SEDDS. Furthermore, formulation coated with Enox showed a higher uptake on human breast adenocarcinoma and human epithelial colorectal adenocarcinoma cell lines, compared to uncoated SEDDS. The study provided the proof-of-principle to propose SEDDS for further investigation as novel candidate for tumor targeting by parenteral route of administration.

EZH2 Regulates Intestinal Inflammation and Necroptosis Through the JNK Signaling Pathway in Intestinal Epithelial Cells.

Inflammatory bowel disease (IBD) is a common disorder of chronic intestinal inflammation that can be caused by the disruption of intestinal immune homeostasis. We aimed to evaluate the role of enhancer of zeste homolog 2 (EZH2) in the inflammatory response and explore the association between EZH2 and necroptosis in human epithelial colorectal adenocarcinoma cell lines. In both in vitro and in vivo models, expression of EZH2 in intestinal tissues was verified by histology. The expression of inflammatory cytokines in cell lines treated with EZH2 siRNA with or without stimulus was analyzed by quantitative real-time polymerase chain reaction. An intestinal necroptosis cell model was established to elucidate whether EZH2 is involved in necroptosis. Our present data indicated that EZH2 expression was decreased in in vitro and in vivo models and in patients with inflammatory bowel disease. EZH2 downregulation increased the expression of inflammatory factors, including TNF-α, IL-8, IL-17, CCL5, and CCL20 in a Caco-2 cell model. The JNK pathway was activated with the reduction of EZH2. In the necroptosis model, downregulation of EZH2 was detected with the upregulation of necroptotic markers RIP1 and RIP3. In addition, EZH2 knockdown with siRNA increased p-JNK and p-c-Jun. Our data suggest that EZH2 plays an important role in the development of intestinal inflammation and necroptosis. Hence, EZH2 could be a potential therapeutic target for IBD.

Expression of Nox4 NADPH Oxidase Splice Variants Generate Hydrogen Peroxide and Modify the Cell Cycle

The NADPH oxidase (Nox) family of proteins generate reactive oxygen species (ROS), which regulate redox‐mediated cell signaling and may lead to oxidative stress. Unlike the other catalytic subunits, Nox4 is mostly constitutively active and regulated by its expression levels. It is reported that Nox4 has splice isoforms, including variant D which retains all FADH and NADPH binding sites of the full length Nox4A, but lacks transmembrane domains. The goal of this study was to characterize expression and function of splice variants Nox4A and Nox4D. We first validated the specificity of qPCR primers used for detection of the splice variants by overexpression of Nox4A and Nox4D in Cos22 cells. Next, we examined expression of these isoforms in cancer cell lines. The relative expression of Nox4A and Nox4D was not significantly different in human epithelial colorectal adenocarcinoma cells (CaCo), human Asian endometrial adenocarcinoma (Ishikawa) glioblastoma (LN229), adenocarcinomic human alveolar basal epithelial (A549) and human umbilical vein endothelial (EA.hy926) cells. We next examined the function of Nox4 splice variants and found that expression of Nox4A and Nox4D both increased ROS levels as compared to control transfected cells. It has been suggested that the subcellular targeting of Nox4A and Nox4D may be different. To test this, we measured hydrogen peroxide levels in the cytosol, mitochondria, and nucleus using the genetically targeted HyPer probes. Whereas Nox4A expression increased ROS in each subcellular compartment of Cos22 cells, Nox4D primarily increased the HyPer signal in the nucleus. We next examined the effect of Nox4 on protein thiol oxidation and found that expression of Nox4A caused oxidation of several protein thiols. Finally, Cos22 cells were transfected with Nox4A, Nox4D, or an empty vector and treated with cytokines. The expression of Nox4 isoforms had a differential effect on the percentage of cells in the G0/G1, S, and G2/M cell cycle phase. In summary, Nox4A and Nox4D splice isoforms are detectable in different cell lines, overexpression of Nox4A and Nox4D increase ROS levels in subcellular organelles and the oxidation of multiple protein thiols, and expression of Nox4A and Nox4D alters the cell cycle. The expression of Nox4 splice isoforms may provide specificity for regulation of subcellular redox signaling.Support or Funding InformationDAS was supported by the American Society for Pharmacology and Experimental Therapeutics (ASPET) sponsored Duke SURPH program. FJM is supported by the Office of Research and Development, Department of Veterans Affairs [2I01BX001729] and the National Institutes of Health [HL130039].This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Cytotoxic 2‐(2′‐Hydroxyphenyl)benzothiazolylquinoline Analogues and their In Vitro Screening through Developmental Assays†

AbstractXenobiotics good pharmacodynamic effect should be evaluated with acceptable drug like properties during the drug discovery process. Benzothiazolyl‐quinoline derivatives are with reported biological and anticancer activity. In the present study, compounds were screened for potency determination in Caco‐2 (Human Epithelial Colorectal Adenocarcinoma) cell line and the most potent compound was evaluated through some of the drug development assays. Experimental protocols were set for stability and solubility (in buffer pH 7.4), metabolic stability, metabolite profiling, Caco‐2 permeability, P‐gp (P‐glycoprotein) inhibition in MDCK (Madin‐Darbey Canine Kidney)‐MDR1 overexpressed cells and CYP induction study by using LC‐MS/MS(Liquid Chromatography Tandem Mass spectrometry) method. The compound was stable and soluble in buffer pH 7.4, less permeable across Caco‐2 cell monolayer, unstable in microsomes, inhibitor of efflux P‐gp transporter and an inducer CYP (Cytochrome P450) 1 A2. The most potent compound (i. e. 6 k) was with high solubility, low permeability and high CLint (intrinsic clearance) in liver microsomes. Therefore it was preliminary classified as class III compound as per biopharmaceutics classification system (BCS) and Class I compound as per biopharmaceutical drug disposition classification system (BDDCS).

Comparative study of effect of Akkermansia muciniphila and its extracellular vesicles on toll-like receptors and tight junction.

We assessed effect of Akkermansia muciniphila and its extracellular vesicles on toll-like receptors and tight junction expression in human epithelial colorectal adenocarcinoma cells (Caco-2). The intestinal microbiota plays an important role in the intestinal homeostasis through its metabolites and derivatives. Interacting with immune cells and intestinal epithelial pattern recognition receptors (PRRs), intestinal microbiota regulates the function of the digestive barrier and inflammation caused by the metabolic diseases. A. muciniphila was cultured on a mucin-containing medium and its EVs was extracted by ultracentrifugation. This bacterium was treated in the MOI=10 and its EVs at the concentrations of 0.1, 0.5 and 5 µg on Caco-2 cells. After 24 hours, the expression of tight junction and toll-like receptor genes were investigated by quantitative real time PCR method. A. muciniphila increased the expression of tlr2 and tlr4. However, EVs at all of the concentrations showed a decrease in tlr4 expression. EVs at the concentrations of 0.1 and 0.5 µg/ml decreased the expression of tlr2. A. muciniphila significantly increased the expression of ocldn and cldn4. Both this bacterium and EVs increased the expression of zo2 in the cell line. Furthermore, this data show that A. muciniphila derived EVs have a dose-independent effect on Caco-2 cells. This preliminary research shows A. muciniphila and its EVs both may increase the integrity of the intestinal barrier. A. muciniphila derived EVs also reduces the inflammation so that EVs of this bacterium can be used as an appropriate target for the treatment of metabolic syndrome and inflammatory bowel diseases.

Cytoplasmic delivery of functional siRNA using pH-Responsive nanoscale hydrogels

The progress of short interfering RNA (siRNA) technologies has unlocked the development of novel alternatives for the treatment of a myriad of diseases, including viral infections, autoimmune disorders, or cancer. Nevertheless, the clinical use of these therapies faces significant challenges, mainly overcoming the charged and large nature of these molecules to effectively enter the cell. In this work, we developed a cationic polymer nanoparticle system that is able to load siRNA due to electrostatic interactions. The pH-responsiveness and membrane-disrupting ability of these carriers make them suitable intracellular delivery vehicles. In the work presented herein we synthesized, characterized, and evaluated the properties of nanoparticles based on 2-diethylaminoethyl methacrylate and tert-butyl methacrylate copolymers. A disulfide crosslinker was incorporated in the nanogels to enable the degradation of the nanoparticles in reductive environments, showing no significant changes on their physicochemical properties. The capability of the developed nanogels to be internalized, deliver siRNA, and induce gene knockdown were demonstrated using a human epithelial colorectal adenocarcinoma cell line. Overall, these findings suggest that this platform exhibits desirable characteristics as a potential siRNA-delivery platform.

Poly (ethyl 2-cyanoacrylate) nanoparticles (PECA-NPs) as possible agents in tumor treatment.

Tumor eradication has many challenges due to the difficulty of selectively delivering anticancer drugs to malignant cells avoiding contact with healthy tissues/organs. The improvement of antitumor efficacy and the reduction of systemic side effects can be achieved using drug loaded nanoparticles. In this study, poly (ethyl 2-cyanoacrylate) nanoparticles (PECA-NPs) were prepared using an emulsion polymerization method and their potential for cancer treatment was investigated. The size, polydispersity index and zeta potential of prepared nanoparticles are about 80 nm, 0.08 and -39.7 mV, respectively. The stability test shows that the formulation is stable for 15 days, while an increase in particle size occurs after 30 days. TEM reveals the spherical morphology of nanoparticles; furthermore, FTIR and 1H NMR analyses confirm the structure of PECA-NPs and the complete polymerization. The nanoparticles demonstrate an in vitro concentration-dependent cytotoxicity against human epithelial colorectal adenocarcinoma cell lines (Caco-2), as assessed by MTT assay. The anticancer activity of PECA-NPs was studied on 3D tumor spheroids models of hepatocellular carcinoma (HepG2) and kidney adenocarcinoma cells (A498) to better understand how the nanoparticles could interact with a complex structure such as a tumor. The results confirm the antitumor activity of PECA-NPs. Therefore, these systems can be considered good candidates in tumor treatment.

In vitro cytotoxic and apoptotic effect of vic‐dioxime ligand and its metal complexes

In this study, vic‐dioxime ligand, (1E,2E)‐2‐(hydroxyimino)‐N′‐[(1E)‐2‐oxo‐2‐phenylethylidene]ethanehydroximohydrazide (LH2), and its Cu (II) and Ni (II) transition metal complexes were synthesized and characterized using analytical and spectroscopic techniques. Furthermore, in vitro cytotoxic and apoptotic effects of this vic‐dioxime ligand and its Cu (II) and Ni (II) complexes on Caco‐2 heterogeneous human epithelial colorectal adenocarcinoma cells were evaluated. The effect of the vic‐dioxime ligand and its Ni (II) and Cu (II) complexes in combination with Campto on the cells was also investigated. The cytotoxicity test was carried using the MTT assay, and the apoptotic effect was tested by DNA diffusion assay. Campto was used as a standard anti‐cancer drug, Caco‐2 cancer cells treated with dimethylsulfoxide acted as solvent control, and human peripheral lymphocytes were used as control.The ligand and its complexes exhibit concentration‐dependent cytotoxic and apoptotic behavior. The ligand induces the weakest cytotoxic and apoptotic effects on both Caco‐2 cancer cells and lymphocytes. The Ni (II) complex of ligand induces high cytotoxic and apoptotic effects on both Caco‐2 cancer cells and lymphocytes. The Cu (II) complex of ligand has high cytotoxic and apoptotic effects on Caco‐2, but weak cytotoxic and apoptotic effects on lymphocytes. The cytotoxic and apoptotic effects of the ligand and its Ni (II) and Cu (II) complexes were found to be concentration dependent, i.e. the higher the concentration is the more cytotoxic it will be. The present findings suggest that Cu (II) complex has the potential to act as a promising anti‐cancer compound against Caco‐2 colon cancer cells.

1,2-Dihydrochromeno[2,3-c]pyrrol-3-one Derivatives: Synthesis and HPLC-ECD Analysis

Ethyl-3-formyl-6-methoxy-(2H)-chromene-2-carboxylate was transformed to N-substituted 1,2-dihydrochromeno[2,3-c]pyrrol-3-ones in a domino reductive amination–lactamization reaction. Isomerization of the double bond and the inherently labile stereogenic center was studied, and HPLC-ECD analysis of a chiral 1,2-dihydrochromeno[2,3-c]pyrrol-3(3aH)-one derivative aided by TDDFT-ECD calculation allowed configurational assignment of the separated enantiomers. Antiproliferative activity of the products was demonstrated on the CaCo-2 human epithelial colorectal adenocarcinoma cell line.

Impact of deoxynivalenol and kaempferol on expression of tight junction proteins at different stages of Caco-2 cell proliferation and differentiation.

The barrier function of intestinal tract is essential to gut health, and the expression of tight junction (TJ) proteins in human epithelial colorectal adenocarcinoma (Caco-2) cells, mimicking the intestinal stem cell proliferation and differentiation, was investigated after treatment by the mycotoxin of deoxynivalenol (DON) and phenolic compound of kaempferol (KAM). The results showed that DON (5 μM) significantly reduced the expression of claudin-4 while kaempferol (100 μM) increased the expression of claudin-3 during Caco-2 cell proliferation. After being cultured for 11 days, the DON treatment, unexpectedly, augmented the expression of claudin-4 with an increased TEER. For differentiated Caco-2 cells after a 21 day culture, both the TEER and claudin-4 levels were significantly reduced by DON while KAM pretreatment alleviated the damage caused by DON accompanying an increase of TEER, claudin-3, and ZO-1. Thus, kaempferol and DON differentially affected the expression of tight junction proteins at different stages of Caco-2 cell proliferation and differentiation, and an increase of the integrity of TJ after KAM pretreatment indicates KAM has the potential to protect the integrity of the barrier function of the intestinal epithelium for improved health.

Computational modeling of distribution coefficients and their correlations with pharmacokinetic properties of 17α-picolyl and 17(E)-picolinylidene androstane derivatives

The present study describes the computational modeling of distribution coefficient (logD) of 17?-picolyl and 17(E)-picolinylidene androstane derivatives, as a group of compounds with significant anticancer activities. The determination of logD is practically important for estimation and prediction of pharmacokinetic and pharmacodynamic behavior of compounds in a living organism and it is related to blood-brain barrier permeability, skin permeability, gastrointestinal absorption, binding to plasma proteins, etc. These features are crucial for the determination of potential drug candidates as well. The results presented in this study include determination of pH versus logD profiles, pH versus molecular charge profiles and determination of isoelectric point of eleven 17?- picolyl androstane derivatives and thirteen 17(E)-picolinylidene androstane derivatives. Since the pH of the organism differs depending on the organ (for example, the pH of the blood is significantly different from the pH of the stomach), these profiles are significant because they indicate in what form the molecule will exist and how it will be distributed between different phases at certain pH value. The influence of tautomerization and resonance was taken into account during the modeling of logD parameters. Eventually, the correlations between logD values and specific absorption, distribution, metabolism, and excretion (ADME) properties, such as human intestinal absorption (HIA) and permeability of heterogeneous human epithelial colorectal adenocarcinoma cells (Caco-2), were determined.

Single‐cell Raman microscopy of microengineered cell scaffolds

AbstractStudying cells in a three‐dimensional (3D) environment has great potential in understanding cell behaviours such as morphology, proliferation, differentiation, and migration. Microengineered 3D cell scaffolds with precise defined geometries have offered a new approach to study cell behaviour and its interactions with scaffolds. The use of Raman spectroscopy to characterise biomolecules is a rapidly expanding area and has been implemented in numerous fields including pharmacology, microbiology, toxicology, and single‐cell studies. However, one area where it remains unexploited despite the vast potential of the technique is in the investigation of 3D cell scaffolds. A combination of Raman microscopy and chemometric approaches have employed to investigate the structure and biochemistry of nanofabricated scaffolds and a cell–scaffold complex. The 3D Raman mapping combined with the use of nanofabricated 3D scaffolds offers a unique opportunity to assess the influence of scaffold architecture on cell body and cell nuclei morphology and biochemistry. For the first time, we have cultured a human epithelial colorectal adenocarcinoma cell line on OrmoComp scaffolds and determined the structure and biochemistry of nanofabricated scaffolds and a cell–scaffold complex with the use of Raman microscopy combined with appropriate data analysis protocols. The results demonstrate the potential of 3D Raman mapping for identifying biochemical and physical variation within single cells as they grow and adhere to 3D scaffolds.

Apple-Derived Nanoparticles Modulate Expression of Organic-Anion-Transporting Polypeptide (OATP) 2B1 in Caco-2 Cells.

Interaction of foods with intestinal transporters has generally been ascribed to small molecules, but recently, edible-plant-derived nanoparticles (NPs) have been suggested to affect intestinal function. Here, we examined the effects of NPs contained in edible fruits on intestinal transporters. Apple-derived NPs (APNPs) were isolated by ultracentrifugation and characterized by measurement of particle size distribution and electron microscopy. Human epithelial colorectal adenocarcinoma (Caco-2) cells internalized fluorescently labeled APNPs, suggesting that fruit-derived NPs would be internalized into intestinal epithelial cells in vivo. We found that the mRNA expression levels of several transporters, including organic-anion-transporting polypeptide (OATP) 2B1, were changed in APNP-treated Caco-2 cells. The protein expression and activity of OATP2B1 were also decreased by APNP exposure, as determined by Western blotting and measurements of [3H]estrone-3-sulfate uptake by Caco-2 cells, respectively. These actions required intact APNPs, because sonication or boiling abrogated the effects. Since the content of apple-derived small molecules in APNPs was negligible, the observed decrease of OATP2B1 expression appears to be mediated by large molecules in the APNPs. We further found that the 3'-untranslated region of the OATP2B1 gene was required for the response to APNPs, suggesting that microRNA in the APNPs might be involved. These results propose a novel mechanism, in which large molecules such as microRNA in food could affect intestinal transporters through food-derived NPs, which also demonstrates that food-derived NPs should be useful for delivery of biologically active large molecules to intestinal tissues.

Phosphatidylcholine synthesis regulates triglyceride storage and chylomicron secretion by Caco2 cells

Intracellular lipid droplets (LDs) supply fatty acids for energy, membrane biogenesis, and lipoprotein secretion. The surface monolayer of LDs is composed of phospholipids, primarily phosphatidylcholine (PC), that stabilize the neutral lipid core of triglyceride (TG). To determine the relationship between PC synthesis and TG storage and secretion in chylomicrons, we used a model of intestinal-derived human epithelial colorectal adenocarcinoma (Caco2) cells with knockout of PCYT1A, which encodes the rate-limiting enzyme CTP:phosphocholine cytidylyltransferase (CCT)α in the CDP-choline pathway, that were treated with the fatty acid oleate. CRISPR/Cas9 knockout of CCTα in Caco2 cells (Caco2-KO cells) reduced PC synthesis by 50%. Compared with Caco2 cells, Caco2-KO cells exposed to oleate had fewer and larger LDs and greater TG accumulation as a result. The addition of exogenous lysophosphatidylcholine to Caco2-KO cells reversed the LD morphology defect. Caco2-KO cells, differentiated into epithelial monolayers, accumulated intracellular TG and had deficient TG and chylomicron-associated apoB48 secretion; apoB100 secretion was unaffected by CCTα knockout or oleate. Metabolic-labeling and LD imaging of Caco2-KO cells indicated preferential shuttling of de novo synthesized TG into larger LDs rather than into chylomicrons. Thus, reduced de novo PC synthesis in Caco2 cells enhances TG storage in large LDs and inhibits apoB48 chylomicron secretion.