Metabonomic Variation of Exopolysaccharide from Rhizopus nigricans on AOM/DSS-Induced Colorectal Cancer in Mice

Beneficial insights into postbiotics against colorectal cancer

Colorectal cancer (CRC) is one of the most prevalent and life-threatening cancer types with limited therapeutic options worldwide. Gut microbiota has been recognized as the pivotal determinant in maintaining gastrointestinal (GI) tract homeostasis, while dysbiosis of gut microbiota contributes to CRC development. Recently, the beneficial role of postbiotics, a new concept in describing microorganism derived substances, in CRC has been uncovered by various studies. However, a comprehensive characterization of the molecular identity, mechanism of action, or routes of administration of postbiotics, particularly their role in CRC, is still lacking. In this review, we outline the current state of research toward the beneficial effects of gut microbiota derived postbiotics against CRC, which will represent the key elements of future precision-medicine approaches in the development of novel therapeutic strategies targeting gut microbiota to improve treatment outcomes in CRC.

CAFs-derived small extracellular vesicles circN4BP2L2 promotes proliferation and metastasis of colorectal cancer via miR-664b-3p/HMGB3 pathway

Our previous research has demonstrated that colorectal cancer (CRC) progression was promoted by circN4BP2L2. This study aimed to further explore the mechanism of circN4BP2L2 in the development of CRC from the perspective of small extracellular vesicles (sEVs). Cancer-associated fibroblasts cell (CAFs) and normal fibroblasts cell (NFs) were isolated from CRC tissues and adjacent tissues, respectively. The ultra-centrifugation was used for extraction of their related sEVs. Cell proliferation and apoptosis were analyzed using CCK-8 and flow cytometry, respectively. Transwell assay was conducted to measure cell migration. The tube formation ability was assessed by tube formation assay. The target relationships between circN4BP2L2 and miR-664b-3p, and miR-664b-3p and HMGB3 were validated by dual-luciferase reporter detection. The effect of CAFs-derived sEV (CAFs-sEVs) circN4BP2L2 on CRC was further studied in nude mice. CAFs-exo promoted cell proliferation, migration, tube formation ability, and inhibited apoptosis of CRC cells. CAFs-sEV circN4BP2L2 knockdown reversed the above results. CircN4BP2L2 directly targeted miR-664b-3p, and HMGB3 was targeted by miR-664b-3p. Moreover, subcutaneous tumorigenesis and liver metastasis of nude mice with CRC were repressed by CAFs-sEV circN4BP2L2 knockdown. CAFs-sEV circN4BP2L2 knockdown restrained CRC cell proliferation and migration by regulating miR-664b-3p/HMGB3 pathway.

Identification of hub genes and pathways in colitis-associated colon cancer by integrated bioinformatic analysis

Background

Colitis-associated colon cancer (CAC) patients have a younger age of onset, more multiple lesions and invasive tumors than sporadic colon cancer patients. Early detection of CAC using endoscopy is challenging, and the incidence of septal colon cancer remains high. Therefore, identifying biomarkers that can predict the tumorigenesis of CAC is in urgent need.

Results

A total of 275 DEGs were identified in CAC. IGF1, BMP4, SPP1, APOB, CCND1, CD44, PTGS2, CFTR, BMP2, KLF4, and TLR2 were identified as hub DEGs, which were significantly enriched in the PI3K-Akt pathway, stem cell pluripotency regulation, focal adhesion, Hippo signaling, and AMPK signaling pathways. Sankey diagram showed that the genes of both the PI3K-AKT signaling and focal adhesion pathways were upregulated (e.g., SPP1, CD44, TLR2, CCND1, and IGF1), and upregulated genes were predicted to be regulated by the crucial miRNAs: hsa-mir-16-5p, hsa-mir-1-3p, et al. Hub gene-TFs network revealed FOXC1 as a core transcription factor. In ulcerative colitis (UC) patients, KLF4, CFTR, BMP2, TLR2 showed significantly lower expression in UC-associated cancer. BMP4 and IGF1 showed higher expression in UC-Ca compared to nonneoplastic mucosa. Survival analysis showed that the differential expression of SPP1, CFRT, and KLF4 were associated with poor prognosis in colon cancer.

Conclusion

Our study provides novel insights into the mechanism underlying the development of CAC. The hub genes and signaling pathways may contribute to the prevention, diagnosis and treatment of CAC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12863-022-01065-7.

Suppression of colitis-associated colorectal cancer by scutellarin through inhibiting Hedgehog signaling pathway activity

BACKGROUND

Colitis-associated colorectal cancer (CAC) is a specific type of colorectal cancer (CRC) and mainly develops from long-term intestinal inflammation. Mounting evidence reveals that activated Hedgehog signaling pathway plays a vital role in the pathogenesis of CRC. Scutellarin is a type of phytochemical flavonoid with a powerful efficacy on various malignancies, including CRC.

AIM

Here, we studied the therapeutic effect of scutellarin on CRC and its direct regulating targets.

METHODS

The CAC model in mice was established by azomethane oxide (AOM) and sodium dextran sulfate (DSS), followed by detection of the efficacies of scutellarin on the carcinogenesis, apoptosis, inflammation, Hedgehog signaling cascade and complicated inflammatory networks in CAC tissues of mice. In CRC SW480 cells, the effects of scutellarin on malignant phenotype, apoptosis and Hedgehog signaling were examined. In TNF-α-stimulated IEC-6 intestinal epithelial cells, the actions of scutellarin on inflammatory response and Hedgehog signals were assessed as well.

RESULTS

Scutellarin significantly ameliorated AOM/DSS-caused CAC in mice and induced apoptosis in CAC tissues of mice, by inhibiting NF-κB (nuclear factor kappa B) -mediated inflammation and Hedgehog signaling axis. RNA-seq and transcriptome analysis indicated that scutellarin regulated complicated inflammatory networks in mouse CAC. Also, scutellarin suppressed the proliferation, migration, colony formation, and induced apoptosis of SW480 cells by down-regulation of Hedgehog signaling pathway activity. Additionally, scutellarin lessened NF-κB-mediated inflammatory response in TNF-α-stimulated IEC-6 cells, by attenuating Hedgehog signaling cascade.

CONCLUSION

Scutellarin potently ameliorates CAC by suppressing Hedgehog signaling pathway activity, underpinning the promising application of scutellarin to CRC in clinical settings.

Combined royal jelly 10-hydroxydecanoic acid and aspirin has a synergistic effect against memory deficit and neuroinflammation

Alzheimer's disease (AD), the most common form of neurodegenerative dementia among the older population, is associated with acute or chronic inflammation. As a nonsteroidal anti-inflammatory drug, aspirin has recently been widely studied in the prevention and treatment of neurodegenerative diseases. However, there is a controversy about the efficacy as well as the adverse effects of aspirin. 10-Hydroxydecanoic acid (10-HDAA) is a characteristic fatty acid found in the honey bee product royal jelly. In this study, we found that 10-HDAA attenuated the activation of the NF-κB pathway, then targeted Ptgs-1/2, the well-known target of aspirin. Hence, combined therapy of 10-HDAA and aspirin was conducted. In vitro assays suggested that this combinatory group alleviated LPS-induced inflammation in BV-2 cells, as assessed by the downregulation of nitric oxide, COX-2, and IL-6 compared to 10-HDAA or aspirin treatment alone. In vivo assays showed that the combined treatment synergistically inhibited the overactivation of glial cells and decreased the levels of pro-inflammatory mediators. Moreover, 10-HDAA alleviated the adverse effects of aspirin on gastrointestinal injuries and microbiota dysbiosis. The Morris water maze test indicated that neither 10-HDAA nor aspirin effectively improved LPS-induced memory dysfunction, but the combined therapy showed synergistic effects. Altogether, our findings support 10-HDAA and aspirin combinatory therapy as the basis for future therapeutics for AD and other neuroinflammation-related diseases with minimal adverse effects.

Exopolysaccharide Produced by Lactiplantibacillus plantarum-12 Alleviates Intestinal Inflammation and Colon Cancer Symptoms by Modulating the Gut Microbiome and Metabolites of C57BL/6 Mice Treated by Azoxymethane/Dextran Sulfate Sodium Salt

Exopolysaccharide produced by Lactiplantibacillus plantarum-12 (LPEPS) exhibited the anti-proliferating effect on human colon cancer cell line HT-29 in vitro. The purpose of the study was to determine the alleviating effects of LPEPS on colon cancer development of the C57BL/6 mice treated by azoxymethane/dextran sulfate sodium salt (AOM/DSS). The C57BL/6 mice treated by AOM/DSS were orally administered LPEPS daily for 85 days. The results showed that LPEPS oral administration enhanced colon tight-junction protein expression and ameliorated colon shortening and tumor burden of the AOM/DSS treated mice. Furthermore, LPEPS oral administration significantly reduced pro-inflammatory factors TNF-α, IL-8, and IL-1β levels and increased anti-inflammatory factor IL-10 level in the serum of the AOM/DSS-treated mice. LPEPS oral administration reversed the alterations of gut flora in AOM/DSS-treated mice, as evidenced by the increasing of the abundance of Bacteroidetes, Bacteroidetes/Firmicutes ratio, Muribaculaceae, Burkholderiaceae, and norank_o__Rhodospirillales and the decreasing of the abundance of Firmicutes, Desulfovibrionaceae, Erysipelotrichaceae, and Helicobacteraceae. The fecal metabolites of the AOM/DSS-treated mice were altered by LPEPS oral administration, involving lipid metabolism and amino acid metabolism. Together, these results suggested that LPEPS oral administration alleviated AOM/DSS-induced colon cancer symptoms of the C57BL/6 mice by modulating gut microbiota and metabolites, enhancing intestine barrier, inhibiting NF-κB pathway, and activating caspase cascade.

[Assessment of biological activities of exopolysaccharides with different relative molecular masses extracted from Rhizopus nigricans]

OBJECTIVE

To evaluate the antioxidant, anti-tumor and immunomodulatory activities of exopolysaccharides with different molecular masses isolated from Rhizopus nigricans.

METHODS

Three polysaccharides with different molecular masses, namely RPS-1, RPS-2 and RPS-3, were separated from the fermentation broth of Rhizopus nigricans by fractional ethanol precipitation, and their capacity for scavenging DPPH, ABTS, and hydroxyl radicals was assessed. Cell counting kit-8 was used to analyze the changes in the viability of MFC, A549 and RAW 264.7 cells following treatments with the 3 polysaccharides; The level of nitric oxide in the supernatant of RAW 264.7 cells was detected using a nitric oxide detection kit, and the apoptosis rate of A549 cells was analyzed with flow cytometry.

RESULTS

All the 3 polysaccharides had good antioxidant activities, and among them RPS-1 with a medium molecular mass exhibited the strongest scavenging capacity for DPPH and ABTS radicals (P < 0.05) while RPS-3 with the lowest molecular mass had the best scavenging activity for hydroxyl radicals (P < 0.01). All the 3 polysaccharides were capable of inhibiting the proliferation of MFC cells and A549 cells, activating the macrophages RAW 264.7 cells, and inducing apoptosis of A549 cells. RPS-2 with the highest molecular mass showed the strongest inhibitory effects against MFC and A549 cells (P > 0.05), and RPS-2 had the strongest activity for inducing apoptosis in A549 cells (P < 0.05). Compared with the other two polysaccharides, RPS-2 more strongly promoted the proliferation of RAW 264.7 cells and enhanced NO release from the cells (P < 0.05).

CONCLUSION

The 3 polysaccharides all have antioxidant, anti-tumor and immunomodulatory activities, and among them RPS-1 and RPS-3 have better antioxidant activities, and RPS-2 has stronger anti-tumor and immunomodulatory activities.

Scutellarin ameliorates colitis-associated colorectal cancer by suppressing Wnt/β-catenin signaling cascade

Dysregulated Wnt/β-catenin signaling pathway plays a critical role in the pathogenesis of colorectal cancer (CRC). Scutellarin, a flavonoid compound in Scutellaria barbata, has been reported to suppress CRC, with the action mechanism elusive. In this study, Scutellarin was found to inhibit the carcinogenesis of colitis-associated cancer (CAC) in mice caused by azoxymethane/dextran sulfate sodium, with alleviation of pathologic symptoms. Besides, Scutellarin attenuated mouse serum concentrations of TNF-α and IL-6, heightened Bax expression and diminished B-cell lymphoma-2 (Bcl-2) level in CAC tissues of mice, through down-regulating Wnt/β-catenin signaling cascade. In CRC HT-29 cells, Scutellarin retarded the proliferation and migration, induced apoptosis, with boosted Bax expression and decreased Bcl-2 level, which may be attributed to its repression of Wnt/β-catenin signals in HT-29 cells. Our findings demonstrate that Scutellarin may ameliorate colitis-associated colorectal cancer by weakening Wnt/β-catenin signaling cascade.

Obacunone reduces inflammatory signalling and tumour occurrence in mice with chronic inflammation-induced colorectal cancer

CONTEXT

Obacunone, a limonoid abundantly found in Citrus fruits, exhibits a variety of bioactivities.

OBJECTIVE

To investigate the effects of obacunone on a colorectal cancer (CRC) mouse model, and clarify its potential molecular mechanisms.

MATERIALS AND METHODS

The male Balb/c mice were induced with azoxymethane and dextran sulfate sodium for 12 weeks. Obacunone (50 mg/kg) was administered via oral gavage three times every week until the end of the experiment. Disease indexes including body weight, spleen weight, bloody diarrhea, colon length, histopathological score, and tumor size were measured. The anti-proliferation activities of obacunone were analyzed by MTT or flow cytometry. The expression of protein and mRNA related to cell proliferation or inflammatory cytokines was determined by Western blot, q-PCR and IHC.

RESULTS

Obacunone significantly alleviated bloody diarrhea, colon shortening (7.35 ± 0.2128 vs. 8.275 ± 0.2169 cm), splenomegaly, histological score (9 ± 0.5774 vs. 6 ± 0.5774) and reduced tumor size (4.25 ± 0.6196 vs. 2 ± 0.5669). Meanwhile, the expression of protein and mRNA related to cell proliferation or inflammatory cytokines was remarkably decreased in tumor tissue. Obacunone inhibited the proliferation activities of colorectal cancer cells. Moreover, obacunone induced colorectal cancer cells G1 and G2 phases arrest, and suppressed the expression of cell cycle genes.

CONCLUSIONS

Obacunone could alleviate CRC via inhibiting inflammatory response and tumor cells proliferation. The results may contribute to the effective utilization of obacunone or its derivatives in the treatment of human CRC.

Inhibitory Effect of a Microecological Preparation on Azoxymethane/Dextran Sodium Sulfate-Induced Inflammatory Colorectal Cancer in Mice

This study aims to investigate the antitumor effect and the possible mechanism of a microecological preparation (JK5G) in mice. The mice treated with AOM/DSS were then randomly divided into the two model groups and the JK5G group, and the blank control group was included. Fecal samples were used for liquid chromatography–mass spectrometry and 16S rRNA gene sequencing analyses to reveal metabolic perturbations and gut flora disorders to demonstrate the effects of JK5G. Compared with the mice in the control group, the weight and food intake of mice after JK5G treatment were both upregulated. Moreover, JK5G could inhibit the growth of colon tumors and prolong the survival rate of mice, as well as inhibit the levels of cytokines in serum. The proportions of lymphocytes, T cells, CD3⁺CD4⁺ T cells, and CD3⁺CD8⁺ T cells in the spleen of the JK5G mice were all significantly increased compared to those in the control group (p < 0.05). Similarly, compared with the model group, the proportions of lymphocytes, B cells, T cells, natural killer T cells, CD3⁺CD4⁺ T cells, and CD3⁺CD8⁺ T cells in the intestinal tumors of the JK5G mice were significantly increased (p < 0.05). Furthermore, 16S rRNA high-throughput sequencing data revealed that Alloprevotella in the JK5G group was significantly upregulated, and Ruminiclostridium, Prevotellaceae_UCG_001, and Acetitomaculum were significantly downregulated. Fecal and serum metabolite analysis detected 939 metabolites, such as sildenafil and pyridoxamine, as well as 20 metabolites, including N-Palmitoyl tyrosine and dihydroergotamine, which were differentially expressed between the JK5G and model groups. Integrated analysis of 16s rRNA and metabolomics data showed that there were 19 functional relationship pairs, including 8 altered microbiota, such as Ruminiclostridium and Prevotellaceae_UCG_001, and 16 disturbed metabolites between the JK5G and model groups. This study revealed that JK5G treatment was involved in the growth of colorectal cancer, which may be associated with the role of JK5G in improving the nutritional status of mice and regulating the tumor microenvironment by regulating the changes of intestinal microbiota and metabolite bands on different pathways.