Effect In Caco-2 Cells Research Articles

Gas chromatography-mass spectrometry based 18O stable isotope labeling of Krebs cycle intermediates

New technologies permit determining metabolomic profiles of human diseases by fingerprinting metabolites levels. However, to fully understand metabolomic phenotypes, metabolite levels and turnover rates are necessary to know. Krebs cycle is the major hub of energy metabolism and cell signaling. Traditionally, 13C stable isotope labeled substrates were used to track the carbon turnover rates in Krebs cycle metabolites. In this study, for the first time we introduce H2[18O] based stable isotope marker that permit tracking oxygen exchange rates in separate segments of Krebs cycle. The chromatographic and non-chromatographic parameters were systematically tested on the effect of labeling ratio of Krebs cycle mediators to increase selectivity and sensitivity of the method. We have developed a rapid, precise, and robust GC-MS method for determining the percentage of 18O incorporation to Krebs cycle metabolites. The developed method was applied to track the cancer-induced shift in the Krebs cycle dynamics of Caco-2 cells as compared to the control FHC cells revealing Warburg effects in Caco-2 cells. We demonstrate that unique information could be obtained using this newly developed 18O-labeling analytical technology by following the oxygen exchange rates of Krebs cycle metabolites. Thus, 18O-labeling of Krebs cycle metabolites expands the arsenal of techniques for monitoring the dynamics of cellular metabolism. Moreover, the developed method will allow to apply the 18O-labeling technique to numerous other metabolic pathways where oxygen exchange with water takes place.

Purification and characterization of antioxidant peptides from yak (Bos grunniens) bone hydrolysates and evaluation of cellular antioxidant activity.

In this study, papain and alcalase were used to generate antioxidant peptides from yak bone protein. The antioxidant activities of hydrolysates in vitro were evaluated by 2,2'-azinobios-(3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging activity, total reducing power, ferrous ion chelating ability and hydroxyl radical scavenging activity. The hydrolysates generated by alcalase possessed the best antioxidant activity among unhydrolyzed protein and samples treated by papain, but the antioxidant activity decreased after simulated gastrointestinal digestion in vitro. The products of simulated gastrointestinal digestion were separated by ultrafiltration and high performance liquid chromatography, and the amino acid sequences of peptides were identified by mass spectrometry. The digestion sites within peptides were predicted by a bioinformatics strategy, and ten peptides were selected for synthesis. Among 10 synthetic peptides, Gly-Phe-Hyp-Gly-Ala-Asp-Gly-Val-Ala, Gly-Gly-Pro-Gln-Gly-Pro-Arg and Gly-Ser-Gln-Gly-Ser-Gln-Gly-Pro-Ala possessed strong antioxidant activities, among which Gly-Phe-Hyp-Gly-Ala-Asp-Gly-Val-Ala had a significant cytoprotective effect in Caco-2 cells under oxidative stress induced by H2O2, which reduced the formation of reactive oxygen species and malondialdehyde, and improved the activity of antioxidant enzymes in cells. These results showed that yak bone peptides exhibited strong antioxidant activity and have a potential value as a new type of natural antioxidant.

Potency of Oral Rehydration Solution in Inducing Fluid Absorption is Related to Glucose Concentration

Oral rehydration solutions (ORSs) is the key treatment of acute diarrhea in children, as it restores the electrolyte balance by stimulating the intestinal sodium/glucose transporter SGLT1 to induce fluid absorption. The World Health Organization (WHO) and The European Society for Paediatric Gastroenterology Hepatology and Nutrition (ESPGHAN) proposed ORSs with different chemical compositions. The main agent of childhood acute gastroenteritis is rotavirus (RV). We evaluate the effects of ORS with different concentration of glucose and sodium on RV induced secretion. Ussing chambers technique was used for electophysiology experiments to evaluate ion fluid flux. ESPGHAN ORS (sodium 60 mmol/L and glucose 111 mmol/L) induced a more potent proabsorptive effect in Caco-2 cells than WHO ORS, and this effect depended on the sodium/glucose ratio. Titration experiments showed that RV-induced fluid secretion can be reverted to a proabsorptive direction when sodium and glucose concentration fall in specific ranges, specifically 45–60 mEq/L and 80–110 mM respectively. The results were confirmed by testing commercial ORSs. These findings indicated that ORS proabsorptive potency depends on sodium and glucose concentrations. Optimal ORS composition should be tailored to reduce RV-induced ion secretion by also considering palatability. These in vitro data should be confirmed by clinical trials.

Chemical Profiling of Astragalus membranaceus Roots (Fish.) Bunge Herbal Preparation and Evaluation of Its Bioactivity

Astragalus membranaceus (Fish.) Bunge is a perennial herb distributed in the northern part of China, and its roots, namely, Hang qi, are included as a natural ingredient in dietary supplement formulations commonly used to treat different disorders such as respiratory infections, diabetes, and heart failure. The availability of a simple method for the determination of the quality of Astragalus herbal preparations could be a challenging issue for commercial purposes. In this study, a liquid chromatography–mass spectrometry (LC–MS)/MS based approach was used to characterize specialized metabolite recovery of 3 commercial hydroalcoholic extracts of A. membranaceus (AMG1, AMG2, AMG3) in addition to a hydroalcoholic extract of A. membranaceus root (AST). The hypoglycemic effect, cholinesterase inhibition, and antioxidant activities were also evaluated. Thirty-one compounds, of which 19 polyphenols and 12 saponins, were identified. The extracts were also quantified by using a sensitive and selective Q-Trap system for their content in flavonoids and astragalosides, selecting astragaloside I and IV as chemical markers. From our results, AMG3 preparation (Axtragyl) was the most abundant in terms of both specialized classes of metabolites, showing a fingerprint similar to that of AST. Interestingly, tested enzyme inhibition ability of flavonoids, daidzein (11) and formononetin (19), reported a higher α-glucosidase inhibition in comparison with that of acarbose used as positive control. The in silico study clarified the interactions among the molecules and the importance of having a free hydroxy group. Moreover, Axtragyl was able to exert protective effects in Caco-2 cells treated with hydrogen peroxide, confirming its ability as a potential protective agent in intestinal injury.

Derivatives of usnic acid cause cytostatic effect in Caco-2 cells

Usnic acid has anti-cancer activity, however, low solubility and toxicity limit the potential. To investigate biological activity of usnic acid derivatives, enantiopure derivatives were synthesised by reacting usnic acid with ethylenediamine, which yielded one dimer product ((+)-1), and two tetra cyclic compounds ((+)-2 and (-)-2). The products were characterised with NMR, and evaluated in vitro in human colon cancer cell line Caco-2 by cell count, phase-contrast microscopy, MTT-assay, measurement of DNA content and cell cycle distribution. All compounds tested showed cytostatic effect in Caco-2 cells, but each compound had a distinct cellular effect. Compound (+)-1 showed anti-proliferative activity by increasing the percentage of cells in S-phase with 25% compared to the control. Compounds (+)-2 and (-)-2 induced paraptosis, but only compound (+)-2 modulated cell cycle distribution by accumulating cells in G2/M-phase by 47% and reduced DNA content by 60%. All compounds express interesting cellular and potential anti-proliferative activity.

Toxic effects and mechanisms of three commonly used fungicides on the human colon adenocarcinoma cell line Caco-2

Fungicides, usually refer to the chemical agents that can effectively control or kill the pathogenic microorganisms. Here, we revealed the effects of three different fungicides, imazalil (IMZ), chlorothalonil (CTL) and carbendazim (CBZ), which are typical broad-spectrum fungicides that are detected at high levels in the natural environment, on heterogeneous human epithelial colorectal cells (Caco-2 cells). All three fungicides had the potential to induce different degrees of toxicity, cause apoptosis, reactive oxygen species (ROS) and even change the cell cycle in the cells. The half maximal inhibitory concentration (IC50) of CTL is the lowest among these three fungicides, suggesting that it may have the highest exposure risk, followed by IMZ, and CBZ. The results of the real-time PCR, Western blotting, and mitochondrial membrane potential (MMP) assays and the activities of key enzymes suggested that CTL induced apoptosis in Caco-2 cells via a mitochondrial-dependent pathway, as indicated by the upregulation of the expression of the apoptotic p53 and bax genes, the increase of the apoptosis marker cytochrome-c, the decrease of mRNA level of bcl-2 gene, and the decrease in the MMP. Exposure to two other fungicides also upregulated the transcriptional level of bax and the expression of cytochrome-c, but the mRNA level of bcl-2 was increased (IMZ) or unchanged (CBZ), suggesting that other pathways may be involved in the induction of cellular apoptosis by these two fungicides. In addition, all three of the fungicides could induce oxidative stress in Caco-2 cells. Our data showed that the three different kinds of fungicides all caused toxic effects in Caco-2 cells through various pathways.

Biotransformed grape pomace as a potential source of anti-inflammatory polyphenolics: Effects in Caco-2 cells

Grape pomace is rich in polymeric phenolic compounds and glycosides. Enzymatic treatments may change grape pomace’s phenolic composition, producing monomers and aglycones. The aims of this study were to evaluate if tannase-biotransformed grape pomace extracts have improved intestinal anti-inflammatory activity using an in vitro colon model and to analyze significant differences between white grape pomace, and mixed grape pomace varieties, due to the absence of a pomace fermentation process during white wine production. No differences were observed in the cytotoxicity caused by different extracts. All extracts, before and after biotransformation at 100 and 200 μg/mL (dry extract w/v) had comparable efficacy in reducing reactive oxygen species production in Caco-2 cells. After treatment and induction of inflammation using an interleukin 1β (IL-1β) challenge, tannase-treated white grape pomace extract at 200 μg/mL was the most efficient treatment in down-regulating nuclear factor kappa B activation by 40%, compared to control. On the other hand, tannase-treated mixed grape pomace extract significantly decreased prostaglandin E2 production by 81% and interleukin-8 by 61%, being more effective than white grape pomace extract. Overall, both grape pomace extracts after biotransformation were more potent in the amelioration of IL-1β-induced inflammation in Caco-2 cells. White grape pomace extract did not show higher anti-inflammatory activity than mixed grape pomace. In general, the biotransformation improved the anti-inflammatory effect in Caco-2 cells, indicating that the application of a bioprocess in grape residues may contribute to the development of new ingredients and nutraceuticals with anti-inflammatory potential.

Antioxidant and gastrointestinal cytoprotective effect of edible polypeptide poly-γ-glutamic acid

The antioxidant effects and cytoprotection of the poly-γ-glutamic acid (γ-PGA) were investigated. γ-PGA with a molecular weight of ~400 kDa showed hydroxyl radical (OH•) averting capacity (HORAC), 85.2% at 1 mg/mL, which was caused by the chelation of transition metal ions and scavenging hydrogen peroxide. Moreover, this γ-PGA showed 94.1% superoxide anion radical (O2•-) scavenging and 96.0% lipid peroxidation inhibition activity at the same concentrations. The IC50 values were 130 ± 4.2, 107 ± 3.5 and 128 ± 3.8 μg/mL against OH•, O2•- and lipid peroxidation, respectively. There was no significant variation in the HORAC of γ-PGA after 9 h, the end point of the simulated digestion model. Furthermore, γ-PGA showed a completely protective effect in Caco-2 cells and probiotic bacteria against oxidative damage at 1 mg/mL. These data suggest that γ-PGA has a potential use as a cytoprotectant in food and feed supplements, cosmetics and biomedical fields.

Eudragit S100 Entrapped Liposome for Curcumin Delivery: Anti-Oxidative Effect in Caco-2 Cells

Curcumin is a natural polyphenol with strong antioxidant activity. However, this molecule shows a very poor bioavailability, instability, and rapid metabolism in vivo. In this work curcumin was loaded in Eudragit-coated liposomes to create a gastroresistant carrier, able to protect its load from degradation and free it at the site of absorption in the colon region. Small unilamellar vesicles were prepared and coated with Eudragit by a pH-driven method. The physico-chemical properties of the prepared systems were assessed by light scattering, transmission electron microscopy, infrared spectroscopy, and differential scanning calorimetry. The uptake of vesicles by Caco-2 cells and the anti-oxidant activity in cells were evaluated. The produced vesicles showed dimensions of about forty nanometers that after covering with Eudragit resulted to have micrometric dimensions at acid pH. The experiments showed that at pH > 7.0 the polymeric coating dissolves, releasing the nanometric liposomes and allowing them to enter Caco-2 cells. Delivered curcumin loaded vesicles were then able to decrease significantly ROS levels as induced by H2O2 in Caco-2 cells. The proposed work showed the possibility of realizing effective gastroresistant curcumin liposome formulations for the delivery of antioxidant molecules to Caco-2 cells, potentially applicable to the treatment of pathological conditions related to intestinal oxidative stress.

Microalgae aqueous extracts exert intestinal protective effects in Caco-2 cells and dextran sodium sulphate-induced mouse colitis.

Microalgae are emerging as a good source of natural nutraceuticals. Here, we examined the intestinal protective effects of microalgae aqueous extracts (MAEs) from Chlorella pyrenoidosa, Spirulina platensis, and Synechococcus sp. PCC 7002 in human intestinal epithelial Caco-2 cells and dextran sodium sulphate (DSS)-induced colitis in C57BL/6 mice. MAEs displayed intestinal barrier-protective activities in Caco-2 cells by increasing the expression of heat shock protein (Hsp)-27 and tight junction proteins of occludin and claudin-4 and attenuating the H2O2-induced intracellular reactive oxygen species production, plasma membrane impairment and apoptosis. They also showed anti-inflammatory potential in tumor necrosis factor (TNF)-α-, interleukin (IL)-1β- and H2O2-stimulated Caco-2 cells by suppressing the secretion of IL-8 and the expression of cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS). The 8 d daily intragastric administration of MAEs during and after 4 d DSS exposure effectively alleviated colitis symptoms of weight loss, diarrhea, rectal bleeding, and colon shortening and histopathology, protected intestinal barrier function by increasing colonic Hsp-25, occludin and claudin-4, and attenuated colonic and systemic inflammation by suppressing colonic myeloperoxidase activity, production of TNF-α, IL-1β and IL-6, expression of COX-2 and iNOS, and peripheral leukocytosis, monocytosis and granulocytosis. Microalgae can thus serve as a functional food to maintain gut health.

A metalloproteinase of the disintegrin and metalloproteinases and the ThromboSpondin Motifs 6 as a novel marker for colon cancer: functional experiments.

Herein, we aimed to investigate the functions of ADAMTS6 in colon cancer and its potential mechanism. Based on the data acquired from TCGA database, we revealed that ADAMTS6 was highly expressed in colon cancer tissues, and high expression of ADAMTS6 predicted worse prognosis in patients with colon cancer. Moreover, qRT-PCR demonstrated that the levels of ADAMTS6 were higher in colon cancer cell lines (NCI-H508, Caco-2, CW-2 and HCT 116) than that in normal control cell line CCD-18Co. Functional experiments displayed that depletion of ADAMTS6 repressed NCI-H508 cell growth, invasion and migration whilst overexpression of ADAMTS6 facilitated Caco-2 cell growth, invasion and migration. Moreover, ADAMTS6 silencing enhanced the protein expression of E-cadherin and reduced the levels of N-cadherin, Vimentin and Snail in NCI-H508 cells, whereas ADAMTS6 overexpression showed the counter effects in Caco-2 cells. The protein levels of p-AKT and p-p65 were decreased by depletion of ADAMTS6 in NCI-H508 cells, while their levels were enhanced by overexpression of ADAMTS6 in Caco-2 cells. These consequences indicated that the accelerating effect of ADAMTS6 on colon cancer cell growth, migration and invasion might be achieved by modulating EMT and AKT/NF-κB signaling pathway, offering important foundations for colon cancer treatment.

Differences between phytosterols with different structures in regulating cholesterol synthesis, transport and metabolism in Caco-2 cells

Abstract Phytosterols have been shown to be effective in reducing blood cholesterol by suppressing intestinal cholesterol absorption in both humans and animals. In present study, the inhibition of cholesterol absorption in Caco-2 cells by ergosterol, ergosterol acetate, β-sitosterol, stigmasterol, campesterol and stellasterol were systematically assessed. Results showed that the phytosterols produced cholesterol-lowering effect in Caco-2 cells. This effect was largely mediated via reducing the biosynthesis of cholesterol (HMGCS1); meditating the key proteins in cholesterol transportation and metabolism (NPC1L1, ABCG5/ABCG8); interrupting the conversion of cholesterol to cholesterol esters (ACAT2). Results indicated that their cholesterol-lowering activity may be correlated with the functional group (hydroxyl or ester) on C-3 position (ergosterol stellasterol). Further researches are needed to confirm the cholesterol-lowering effects of phytosterols with functional group (methyl or ethyl) on C-24 and the functional groups on C-22 position.

Anti-Proliferative Effect of Melamine on Human Colon Adenocarcinoma Cells

Melamine is an organic chemical used primarily as a plastics stabilizer and fire retardant. Also, it was used to fraudulently elevate the protein content of animal feed and dairy products, which led to infant kidney diseases and pet deaths. In this study, melamine was studied for its effects on growth in the human colon adenocarcinoma cells (Caco-2). Different concentrations of medium-dissolved melamine were incubated for 24 h with Caco-2 cells and tested for its anti-proliferative potential using MTT assay. Half-maximal inhibitory concentration (IC 50 ) of melamine was calculated from dose-response curve and found to be 14636 µg/L in the cells. The results demonstrated that the dose dependent melamine decreased cell proliferation and direct anti-proliferative effect in Caco-2 cells.

Cytoprotective Effect of Ligustrum robustum Polyphenol Extract against Hydrogen Peroxide-Induced Oxidative Stress via Nrf2 Signaling Pathway in Caco-2 Cells.

Ligustrum robustum is a traditional herbal tea that is widely distributed in southwest China. The health effects of L. robustum are characteristics of clearing heat, antioxidant, inducing resurgence, and improving digestion. However, the molecular mechanisms related to these effects, particularly the antioxidant mechanism, have been seldom reported. The objective of this study was to assess antioxidative capacity of L. robustum, and its protective effects and mechanisms against hydrogen peroxide (H2O2) - induced toxicity in Caco-2 cells. Total phenolic contents, free radical scavenging activity, and reducing capacity of L. robustum were measured. The effects of L. robustum on the cell viability and antioxidant defense system were explored. The expression of nuclear factor E2 related factor 2 (Nrf2) and antioxidant genes: quinone oxidoreductase 1 (NQO1), heme oxygenase-1 (HO-1), and glutamate cysteine ligase (GCL) were analyzed by western blot and qPCR. Pretreatment of L. robustum could significantly reduce H2O2-induced toxicity, decrease the level of reactive oxygen species (ROS) and malondialdehyde (MDA), and increase the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and glutathione reductase (GR). By activating the expression of Nrf2 and antioxidant genes (NQO1, HO-1, and GCL), L. robustum exerts cytoprotective effect in Caco-2 cells dealt with H2O2. Therefore, the well-established model of Caco-2 cells demonstrates that L. robustum may modulate the cytoprotective effect against the H2O2-induced oxidative stress through the Nrf2 signaling pathway.

Cytotoxicity and biological capacity of sulfur-free lignins obtained in novel biorefining process

Lignin is one of the most promising and versatile products obtained in biorefineries due to its diverse therapeutic properties such as antimicrobial, antioxidant and anti-inflammatory activity. However, these properties depend on the source of lignin and the way it was isolated from the biomass. In this study, four different lignins are compared (extracted with Aquasolv (ASL1, ASL2), Organosolv (OSL) and Alkali (ALK) processes) for their cellular antioxidant capacity, anti-diabetic activity, free radical scavenging and cytotoxicity. Alkali and Organosolv lignins showed the highest antioxidant capacity 1159.815 μmol TE g−1 and 1463.415 μmol TE g−1, respectively, in agreement with their highest amount of free –OH groups. Additionally, OSL showed the highest inhibition in the antidiabetic assay followed by ASL1 with values for α–amylase of 3.6 mg/ml and 4.3 mg/ml respectively, and α–glucosidase 1.6 mg/ml and 2.5 mg/ml correspondingly. Nevertheless, cell-based assays revealed that ASL has the lowest cytotoxic effect in Caco-2 cells and, thus, is 10 times less cytotoxic than Alkali and OSL. This work suggests the applicability of ASL for high value applications such as cosmetics or pharmaceuticals. Industrial relevanceIndustrially, Liquid Hot Water (LHW) and Organosolv processes may appear as promising biorefining technologies in the following years. Lignin produced is free of sulfur, can be labelled as clean and environmentally-friendly and in this study, was proven that LHW lignin is non cytotoxic. The findings in this paper showed that different sources of lignin can be used in product formulation for life science purposes, thus opening a broad spectrum of possibilities for lignin valorisation in biorefineries.

Biological effects and potential mechanisms of action of Pistacia lentiscus Chios mastic extract in Caco-2 cell model

Pistacia lentiscus L. (PL) is an evergreen shrub from which it is derived a precious aromatic resin called mastic gum or mastic. This extract possesses numerous proprieties, such as antimicrobial, anti-inflammatory, anticancer, etc. The aim of this study was to investigate the biological activities of a patented PL Chios mastic extract in a human small intestine mucosa model, the Caco-2 cells. PL Chios mastic extract showed no toxic effect in Caco-2 cells treated with lower concentrations (<100 μg/ml). Pro-inflammatory cytokines were not increased in Caco-2 cells and disaccharidase activity as well as sucrase–isomaltase expression were decreased at 50 μg/ml, suggesting a potential role in glycaemic control. Also paracellular permeability was reduced in Caco-2 cells and remarkably this extract induced a barrier effect useful in protecting against chemical or biological insults.

Co-Loading of Ascorbic Acid and Tocopherol in Eudragit-Nutriosomes to Counteract Intestinal Oxidative Stress.

The present study aimed at developing a new vesicular formulation capable of promoting the protective effect of ascorbic acid and tocopherol against intestinal oxidative stress damage, and their efficacy in intestinal wound healing upon oral administration. A pH-dependent copolymer (Eudragit® L100), a water-soluble prebiotic fibre (Nutriose® FM06), a phospholipid mixture (Lipoid S75), and two natural antioxidants (ascorbic acid and tocopherol) were combined to fabricate eudragit-nutriosomes by a simple, solvent-free procedure. The vesicles were spherical and oligolamellar, with some multicompartment structures in Eudragit-nutriosomes, small in size (~100 nm), with highly negative zeta potential. The effect of Eudragit® and Nutriose® on the stability on storage and in simulated gastrointestinal fluids were confirmed by the Turbiscan® technology and in vitro studies, respectively. Eudragit-nutriosomes exhibited a protective effect against H2O2-induced oxidative stress, and a proliferative effect in Caco-2 cells, as they provided the closure of the scratched area after 96 h of incubation.

Identification of a Novel Potential Probiotic Lactobacillus plantarum FB003 Isolated from Salted-Fermented Shrimp and its Effect on Cholesterol Absorption by Regulation of NPC1L1 and PPARα.

Cholesterol-lowering activity is an important health benefit of lactic acid bacteria (LAB). This study aimed to screen LAB strains with cholesterol-lowering activities from salted fermented shrimp and evaluate probiotic characteristics and cholesterol-lowering potentials of these LAB isolates. Among 191 lactic acid strains isolated from traditional salted-fermented shrimp food, FB003 isolate showed the highest cholesterol-lowering activity and investigated as probiotics with cholesterol-lowering ability. Biochemical analysis and 16S rRNA sequencing revealed that this LAB isolate was Lactobacillus plantarum FB003. To screen probiotic trait, L. plantarum FB003 was found to be susceptible to six antibiotics tested and broad-spectrum antimicrobial activity. It also produced various enzymes such as galactosidase, glucosidase, and mannosidase. In addition, this strain showed autoaggregation, and coaggregation capacity for various pathogens. Moreover, it could adhere to Caco-2 cells and be exerted lowering cholesterol effects in Caco-2 cells via an upregulation of PPARα to inhibit NPC1L1 mRNA expression. Strain L. plantarum FB003 might be effective as a candidate probiotic with high cholesterol-lowering activity. The results of the present study suggest that L. plantarum FB003 have an impact on preventing high cholesterol level and may be used as starter culture for shrimp fermentation.

Mucosal Penetrating Bioconjugate Coated Upconverting Nanoparticles That Integrate Biological Tracking and Photodynamic Therapy for Gastrointestinal Cancer Treatment.

The integration of noninvasive photodynamic therapy (PDT) and imaging in the gastrointestinal tract is extremely challenging because of the limited light penetration in traditional PDT, and physiological barriers such as inorganic salts and mucous layers. Herein, d-α-tocopherol polyethylene glycol 1000 succinate-succinic acid-mercapto-ethylamine (TPGS-SH) was used to functionalize upconverting nanoparticles (UCNPs) and endow the modified UCNPs@TPGS-SH nanoparticles with excellent hydrophilic properties, biocompatibility, gastrointestinal stability and mucus penetration. After loading the photosensitizer zinc phthalocyanine (ZnPC) onto UCNPs@TPGS-SH, the resulting nanosystem ZnPC-UCNPs@TPGS-SH converted near-infrared light (NIR) to visible light, which activated ZnPC to generate singlet oxygen that showed a strong killing effect in Caco-2 cells. In-situ mucosal penetration assay showed that ZnPC-UCNPs@TPGS-SH accumulated more in the enterocytes of duodenum, jejunum and ileum, and less in the mucosal layer compared to ZnPC-UCNPs@TPGS. Moreover, cellular uptake and in situ tracing experiments confirmed that the florescent light emitted by UCNPs upon upconversion of deep penetrating NIR light could also serve as an imaging probe. These findings demonstrate the promising potential of this theranostic nanosystem for simultaneous deep penetrating biological tracing and PDT in gastrointestinal cancer.

Narrow line between benefit and harm: Additivity of hyperthermia to cisplatin cytotoxicity in different gastrointestinal cancer cells.

AIMTo investigate the response to hyperthermia and chemotherapy, analyzing apoptosis, cytotoxicity, and cisplatin concentration in different digestive system cancer cells.METHODSAGS (gastric cancer cell line), Caco-2 (colon cancer cell line) and T3M4 (pancreatic cancer cell line) were treated by cisplatin and different temperature setting (37 °C to 45 °C) either in isolation, or in combination. Treatment lasted for one hour. 48 h after the treatment viability was evaluated by MTT, cell apoptosis by Annexin V-PE and 7ADD flow cytometry. Intracellular cisplatin concentration was measured immediately after the treatment, using mass spectrometry. Isobologram analysis was performed to evaluate the mathematical combined effect of temperature and cisplatin.RESULTSAGS cells were the most sensitive to isolated application of hyperthermia. Hyperthermia, in addition to cisplatin treatment, did not provoke a synergistic effect at intervals from 37 °C to 41 °C in neither cancer cell line. However, a temperature of 43 °C enhanced cisplatin cytotoxicity for Caco-2 cells. Moreover, isobologram analysis revealed mathematical antagonistic effects of cisplatin and temperature combined treatment in AGS cells; variations between synergistic, additive, and antagonistic effects in Caco-2 cells; and additive and antagonistic effects in T3M4 cells. Combined treatment enhanced initiation of cell apoptosis in AGS, Caco-2, and T3M4 cells by 61%, 20%, and 19% respectively. The increase of intracellular cisplatin concentration was observed at 43 °C by 30%, 20%, and 18% in AGS, Caco-2, and T3M4 cells, respectively.CONCLUSIONIn addition to cisplatin, hyperthermia up to 43 °C does not affect the viability of cancer cells in a synergistic manner.