Enhancement of colon carcinogenesis by the combination of indole-3 carbinol and synbiotics in hemin-fed rats

Bidirectional effects of the tryptophan metabolite indole-3-acetaldehyde on colorectal cancer

BACKGROUND

Colorectal cancer (CRC) has a high incidence and mortality. Recent studies have shown that indole derivatives involved in gut microbiota metabolism can impact the tumorigenesis, progression, and metastasis of CRC.

AIM

To investigate the effect of indole-3-acetaldehyde (IAAD) on CRC.

METHODS

The effect of IAAD was evaluated in a syngeneic mouse model of CRC and CRC cell lines (HCT116 and DLD-1). Cell proliferation was assessed by Ki-67 fluorescence staining and cytotoxicity tests. Cell apoptosis was analysed by flow cytometry after staining with Annexin V-fluorescein isothiocyanate and propidium iodide. Invasiveness was investigated using the transwell assay. Western blotting and real-time fluorescence quantitative polymerase chain reaction were performed to evaluate the expression of epithelial-mesenchymal transition related genes and aryl hydrocarbon receptor (AhR) downstream genes. The PharmMapper, SEA, and SWISS databases were used to screen for potential target proteins of IAAD, and the core proteins were identified through the String database.

RESULTS

IAAD reduced tumorigenesis in a syngeneic mouse model. In CRC cell lines HCT116 and DLD1, IAAD exhibited cytotoxicity starting at 24 h of treatment, while it reduced Ki67 expression in the nucleus. The results of flow cytometry showed that IAAD induced apoptosis in HCT116 cells but had no effect on DLD1 cells, which may be related to the activation of AhR. IAAD can also increase the invasiveness and epithelial-mesenchymal transition of HCT116 and DLD1 cells. At low concentrations (< 12.5 μmol/L), IAAD only exhibited cytotoxic effects without promoting cell invasion. In addition, predictions based on online databases, protein-protein interaction analysis, and molecular docking showed that IAAD can bind to matrix metalloproteinase-9 (MMP9), angiotensin converting enzyme (ACE), poly(ADP-ribose) polymerase-1 (PARP1), matrix metalloproteinase-2 (MMP2), and myeloperoxidase (MPO).

CONCLUSION

Indole-3-aldehyde can induce cell apoptosis and inhibit cell proliferation to prevent the occurrence of CRC; however, at high concentrations (≥ 25 μmol/L), it can also promote epithelial-mesenchymal transition and invasion in CRC cells. IAAD activates AhR and directly binds MMP9, ACE, PARP1, MMP2, and MPO, which partly reveals why it has a bidirectional effect.

Bidirectional effects of the tryptophan metabolite indole-3-acetaldehyde on colorectal cancer

BACKGROUND

Colorectal cancer (CRC) has a high incidence and mortality. Recent studies have shown that indole derivatives involved in gut microbiota metabolism can impact the tumorigenesis, progression, and metastasis of CRC.

AIM

To investigate the effect of indole-3-acetaldehyde (IAAD) on CRC.

METHODS

The effect of IAAD was evaluated in a syngeneic mouse model of CRC and CRC cell lines (HCT116 and DLD-1). Cell proliferation was assessed by Ki-67 fluorescence staining and cytotoxicity tests. Cell apoptosis was analysed by flow cytometry after staining with Annexin V-fluorescein isothiocyanate and propidium iodide. Invasiveness was investigated using the transwell assay. Western blotting and real-time fluorescence quantitative polymerase chain reaction were performed to evaluate the expression of epithelial-mesenchymal transition related genes and aryl hydrocarbon receptor (AhR) downstream genes. The PharmMapper, SEA, and SWISS databases were used to screen for potential target proteins of IAAD, and the core proteins were identified through the String database.

RESULTS

IAAD reduced tumorigenesis in a syngeneic mouse model. In CRC cell lines HCT116 and DLD1, IAAD exhibited cytotoxicity starting at 24 h of treatment, while it reduced Ki67 expression in the nucleus. The results of flow cytometry showed that IAAD induced apoptosis in HCT116 cells but had no effect on DLD1 cells, which may be related to the activation of AhR. IAAD can also increase the invasiveness and epithelial-mesenchymal transition of HCT116 and DLD1 cells. At low concentrations (< 12.5 μmol/L), IAAD only exhibited cytotoxic effects without promoting cell invasion. In addition, predictions based on online databases, protein-protein interaction analysis, and molecular docking showed that IAAD can bind to matrix metalloproteinase-9 (MMP9), angiotensin converting enzyme (ACE), poly(ADP-ribose) polymerase-1 (PARP1), matrix metalloproteinase-2 (MMP2), and myeloperoxidase (MPO).

CONCLUSION

Indole-3-aldehyde can induce cell apoptosis and inhibit cell proliferation to prevent the occurrence of CRC; however, at high concentrations (≥ 25 μmol/L), it can also promote epithelial-mesenchymal transition and invasion in CRC cells. IAAD activates AhR and directly binds MMP9, ACE, PARP1, MMP2, and MPO, which partly reveals why it has a bidirectional effect.

Indole-3-Carbinol Promotes Apoptosis and Inhibits the Metastasis of Esophageal Squamous Cell Carcinoma by Downregulating the Wnt/β-Catenin Signaling Pathway

The incidence and mortality rates of esophageal squamous cell carcinoma (ESCC) have been significantly increasing in China. Indole-3-carbinol (I3C), a naturally occurring component in cruciferous vegetables, is an effective cancer therapy. Yet, its effect and action mechanism in ESCC are still not fully understood. This study explored the role of I3C in ESCC in vitro and in vivo by focusing on the Wnt/β-catenin signaling pathway. MTT and flow cytometry were used to assess cell viability and apoptosis in EC18 and TE1 cells, while wound healing and transwell assays were used to investigate cell migration and invasion in vitro. Expression of β-catenin, c-myc, and cyclin D1 was determined by Western blot; LiCl (an agonist of the canonical Wnt signaling that inhibits GSK3β activity) was used to assess the role of I3C on the Wnt/β-catenin signaling pathway. For in vivo experiments, nude BALB/c mice bearing EC18 xenografts were treated with I3C and/or LiCl. I3C promoted ESCC apoptosis and inhibited cell migration and invasion by downregulating β-catenin, c-myc, and cyclin D1 in vitro and decreased the tumor growth in vivo; this process was reversed by LiCl treatment. In summary, I3C inhibits ESCC malignant behavior by suppressing the Wnt/β-catenin signaling pathway, thus deeming it a promising drug for ESCC treatment.

Identification of high-concern organic pollutants in tap waters from the Yangtze River in China based on combined screening strategies

Recently, numerous organic pollutants have been detected in water environment. The safety of our drinking water has attracted widespread attention. Effective methods to screen and identify high-concern substances are urgently needed. In this study, the combined workflow for the detection and identification of high-concern organic chemicals was established and applied to tap water samples from the Yangtze River Basin. The solid phase extraction (SPE) sorbents were compared and evaluated and finally the HLB cartridge was selected as the best one for most of the contaminants. Based on target, suspect and non-target analysis, 3023 chemicals/peaks were detected. Thirteen substances such as diundecyl phthalate (DUP), 2-hydroxyatrazine, dioxoaminopyrine and diethyl-2-phenylacetamide were detected in drinking water in the Yangtze River Basin for the very first time. Based on three kinds of prioritization principles, 49 ubiquitous, 103 characteristic chemicals and 13 inefficiently removed chemicals were selected as high-concern substances. Among them, 8, 31, 9, 3, 4 substances overlapped with the toxic, risky or high-concern chemicals lists in China, America, European Union, Japan, Korea, respectively. Specific management and removal strategies were further recommended. The workflow is efficient for identification of key pollutants.

Encapsulation of indole-3-carbinol in Pickering emulsions stabilized by OSA-modified high amylose corn starch: Preparation, characterization and storage stability properties

The stability of hydrophobic bioactive compound indole-3-carbinol (I3C) is a challenge for application. In this work, Pickering emulsions were prepared to encapsulate I3C. As the emulsifier, high amylose corn starch was pretreated by acid hydrolysis, afterwards modified by different concentrations of octenyl succinic anhydride (OSA), and their emulsions were evaluated. The XRD, SEM and FTIR results indicated the successful modification. ζ-potential, mean droplet size and emulsification index (EI) of the emulsions confirmed that modified starch with a higher degree of substitution (DS) was more effective for enhancing the storage stability. The results of encapsulation efficiency (EE) and retention degree of I3C after 14 d also proved the assumption. Moreover, the Pickering emulsions protected I3C against ultraviolet light and achieved controlled release in vitro. The food-grade Pickering emulsion loading I3C is promising to be used as a nutrient or dietary supplement for food applications.

Inulin as a functional ingredient and their applications in meat products

Inulin, a fructan-type non-digestible carbohydrate, is a natural functional dietary fiber found in selected plants including chicory, garlic, onion, leeks and asparagus. Due to increasing popularity of inulin and rising awareness toward its low calorie value and prebiotic related health implications, consumers are becoming more conscious on consuming inulin incorporated foods. In this review, the scientific studies published in recent years regarding potential applications of inulin in meat products; and their effects on physicochemical and sensory properties, and health implications are discussed. Meat based functional foods with inulin can lead to enhance digestive health by reducing the risk of diseases like constipation, irritable bowel syndrome, inflammatory bowel disease and colorectal cancer. Inulin can be an interesting prebiotic ingredient in healthier meat formulations, apart from being a fat replacer and dietary fiber enhancer.

Synbiotic supplementation attenuates the promoting effect of indole-3-carbinol on colon tumorigenesis

Indole-3 carbinol (I3C) has shown dual effects on the promotion and progression stages of colon carcinogenesis while synbiotics (Syn) have exerted anti-carcinogenic activities in most rodent studies. This study aimed to investigate the effects of I3C given alone or together with a Syn intervention on 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis. All animals were given four subcutaneous DMH injections (4×40 mg/kg bodyweight, twice a week for two weeks) and then received either basal diet (G1), basal diet containing I3C (1g/kg chow) (G2) or basal diet containing I3C+Syn (I3C + inulin 50g/kg chow + Bifidobacterium lactis BB-12^®), 2.5×10¹⁰ cfu/g of basal diet), (G3) for 21 weeks. Dietary I3C (G2) significantly increased tumour volume and cell proliferation when compared to the DMH control group (G1). Syn intervention (G3) significantly reduced tumour volume and cell proliferation when compared to I3C (G2). The colon tumours found were classified into well-differentiated tubular adenomas or adenocarcinomas. Dietary I3C or I3C+Syn did not significantly affect the incidence and the multiplicity of tumours in comparison with the DMH control group. Furthermore, Syn intervention (G3) increased Gstm1 and reduced Mapk9 gene expression in colonic tumours. The findings of the present study show that the dietary I3C shows a weak promoting activity, while the combination with Syn ameliorates I3C effects.

The Use of Natural Fiber-Rich Food Product Is Safe and Reduces Aberrant Crypt Foci in a Pre-Clinical Model

BACKGROUND

Colorectal cancer is a highly prevalent disease, requiring effective strategies for prevention and treatment. The present research aimed to formulate a natural fiber-rich food product (NFRFP) and to evaluate its safety, toxicogenetics, and effects on aberrant crypt foci induced by 1,2-dimethyl-hydrazine in a preclinical model.

METHODS

A total of 78 male Wistar rats were distributed in six experimental groups: negative control, positive control (1,2-Dimethylhydrazine-40 mg/Kg), and four groups fed with 10% NFRFP: NFRFP, pre-treatment protocol, simultaneous treatment, and post-treatment protocol.

RESULTS

The NFRFP was shown to be a good source of fibers and did not change biometric, biochemical, hematological, and inflammatory parameters, and did not induce signs of toxicity and genotoxicity/carcinogenicity. NFRFP exhibited a chemopreventive effect, in all protocols, with damage reduction (% DR) of 75% in the comet test. NFRFP reduced the incidence of aberrant crypt outbreaks by 49.36% in the post-treatment protocol.

CONCLUSIONS

The results suggest the applicability of NFRFP in the human diet due to potential production at an industrial scale and easy technological application in different products, since it could be incorporated in food without altering or causing small changes in final product sensory characteristics.

Dietary hemin promotes colonic preneoplastic lesions and DNA damage but not tumor development in a medium-term model of colon carcinogenesis in rats

Red and processed meat consumption has been strongly related to increase the risk of colorectal cancer (CRC), although its impact is largely unknown. Hemin, an iron-containing porphyrin, is acknowledged as a putative factor of red and processed meat pro-carcinogenic effects. The aim of this study was to investigate the effects of high dietary hemin on the promotion/progression stages of 1,2-dimethylhydrazine (1,2-DMH)-induced colon carcinogenesis. Twenty-four Wistar male rats were given four subcutaneous 1,2-DMH injections and received either balanced diet or balanced diet supplemented with hemin 0.5 mmol/kg for 23 weeks. Colon specimens were analyzed for aberrant crypt foci (ACF) and tumor development. Dietary hemin significantly increased ACF number and fecal water cytotoxicity/genotoxicity in Caco-2 cells when compared to 1,2-DMH control group. However, tumor incidence, multiplicity and cell proliferation did not differ between 1,2-DMH + hemin and 1,2-DMH control group. Gene expression analysis of 91 target-genes revealed that only three genes (Figf, Pik3r5 and Tgfbr2) were down-regulated in the tumors from hemin-fed rats compared to those from 1,2-DMH control group. Therefore, the findings of this study show that high hemin intake promotes mainly DNA damage and ACF development and but does not change the number nor incidence of colon tumors induced by 1,2-DMH in male rats.