Expression of nucleus accumbens-1 in colon cancer negatively modulates antitumor immunity.

BACKGROUND: Nucleus accumbens-1 (NAC-1) is highly expressed in a variety of tumors, including colon cancer, and is closely associated with tumor recurrence, metastasis, and invasion. AIM: To determine whether and how NAC-1 affects antitumor immunity in colon cancer. METHODS: NAC-1-siRNA was transfected into RKO colon cancer cells to knock down NAC expression; tumor cells with or without knockdown of NAC-1 were treated with CD8+ T cells to test their cytocidal effect. The level of the immune checkpoint programmed death receptor-1 ligand (PD-L1) in colon cancer cells with or without knockdown of NAC-1 was analyzed using Quantitative real-time polymerase chain reaction and Western blotting. A double luciferase reporter assay was used to examine the effects of NAC-1 on the transcription of PD-L1. Mice bearing MC-38-OVA colon cancer cells expressing NAC-shRNA or control-shRNA were treated with OT-I mouse CD8+ T cells to determine the tumor response to immunotherapy. Immune cells in the tumor tissues were analyzed using flow cytometry. NAC-1, PD-L1 and CD8+ T cells in colon cancer specimens from patients were examined using immunohistochemistry staining. RESULTS: Knockdown of NAC-1 expression in colon cancer cells significantly enhanced the cytocidal effect of CD8+ T cells in cell culture experiments. The sensitizing effect of NAC-1 knockdown on the antitumor action of cytotoxic CD8+ T cells was recapitulated in a colon cancer xenograft animal model. Furthermore, knockdown of NAC-1 in colon cancer cells decreased the expression of PD-L1 at both the mRNA and protein levels, and this effect could be rescued by transfection of an RNAi-resistant NAC-1 expression plasmid. In a reporter gene assay, transient expression of NAC-1 in colon cancer cells increased the promoter activity of PD-L1, indicating that NAC-1 regulates PD-L1 expression at the transcriptional level. In addition, depletion of tumoral NAC-1 increased the number of CD8+ T cells but decreased the number of suppressive myeloid-derived suppressor cells and regulatory T cells. CONCLUSION: Tumor expression of NAC-1 is a negative determinant of immunotherapy.

Roseburia intestinalis stimulates TLR5-dependent intestinal immunity against Crohn's disease.

BACKGROUND: Crohn's disease (CD) is a chronic inflammatory disorder characterized by intestinal immune dysfunction. Multiple factors, including gut dysbiosis, are involved in the pathogenesis of CD. However, the effect of commensal bacteria on controlling the inflammatory response in individuals with CD remains unclear. METHODS: We detected Toll-like receptor 2 (TLR2), TLR4, and TLR5 expression in Roseburia intestinalis (R. intestinalis)-treated mice with 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis. Then, we quantified the signs of colonic inflammation, the proportion of regulatory T cells (Tregs) and the expression of thymic stromal lymphopoietin (TSLP) and transforming growth factor (TGF)-ß in TLR-5-deficient (Tlr5-/-) mice, bone marrow chimera mice (generated using wild-type (WT) and Tlr5-/- mice), and anti-TSLP/anti-TGFß-treated C57BL/6 mice with colitis induced by TNBS. In vitro, we used the lipopolysaccharide (LPS)-stimulated human intestinal epithelial cell line Caco-2 as an inflammatory colon cell model treated with or without the TLR5-siRNA intervention in the presence of R. intestinalis and incubated human monocyte-derived dendritic cells (DCs) with the supernatant of Caco-2 cells. Then, we cocultured human CD4+ T cells with the aforementioned DCs to determine the differentiation of Tregs. Additionally, samples from patients with CD were collected to analyse the correlation between TLR5/TSLP/TGFß expression and the percentage of R. intestinalis. FINDINGS: Here, we show that R. intestinalis inhibits the development of CD by increasing the differentiation of anti-inflammatory Tregs. Mechanistically, R. intestinalis stimulates TSLP production in intestinal epithelial cells (IECs) through TLR5 but not TLR2 or TLR4. TSLP produced by IECs specifically induces the secretion of interleukin-10 (IL-10) and TGFß from DCs, which is necessary for subsequent Treg differentiation. Consequently, the depletion of TLR5 (using Tlr5-/- mice) or inhibition of TSLP (using anti-TSLP neutralizing antibodies) attenuates the protective effect of R. intestinalis on experimental colitis in mice. Importantly, the expression of TSLP in patients with CD is positively correlated with the level of R. intestinalis. INTERPRETATION: These findings reveal the previously unknown mechanism of R. intestinalis-mediated intestinal immune regulation, which may provide the basis for new therapeutic strategies for CD. FUNDING: This work was funded by the National Natural Science Foundation of China (81670504 and 81970494), the Key Project of Research and Development Plan of Hunan Province (2019SK2041) and the Changsha Municipal Natural Science Foundation (kq2014258).

Functional Phenotypes of Peritoneal Macrophages Upon AMD3100 Treatment During Colitis-Associated Tumorigenesis.

CXCL12 and its receptor CXCR4 are independent prognostic factors in colorectal cancer. AMD3100 is the most frequently used FDA-approved antagonist that targets the CXCL12-CXCR4 axis in clinical trials. We aimed to explore the role of AMD3100 and its effect on peritoneal macrophages' functional phenotypes during colitis-associated tumorigenesis. We treated AMD3100 in a colitis-associated colon cancer mouse model and evaluated its effect on tumorigenesis. The phagocytosis activities of peritoneal macrophages were measured by flow cytometry. The proportions of macrophages and M1/M2 subpopulations were investigated by flow cytometry, ELISA, and immunochemistry. Serum levels of pro-inflammatory and anti-inflammatory cytokines were measured by LEGENDplex™ kits. Transwell assay and qRT-PCR were performed to investigate the direct effect of CXCL12 on macrophages in vitro. We demonstrated that AMD3100 treatment reduced the inflammatory damages in the colonic mucosal and ameliorated tumor development in experimental mice. We found that the phagocytosis activities of peritoneal macrophages fluctuated during colitis-associated tumorigenesis. The proportions of peritoneal macrophages and M1/M2 subpopulations, together with their metabolite and cytokines, changed dynamically in the process. Moreover, AMD3100 regulated the functional phenotypes of macrophages, including reducing the recruiting activity, promoting polarization to the M1 subpopulation, and reducing IL-12 and IL-23 levels in serum. Our study contributes to understanding dynamic changes of peritoneal macrophages upon AMD3100 treatment during tumorigenesis and sheds light on the potential therapeutic target of AMD3100 and peritoneal macrophages against colitis-associated colon cancer.

miR-126 downregulates CXCL12 expression in intestinal epithelial cells to suppress the recruitment and function of macrophages and tumorigenesis in a murine model of colitis-associated colorectal cancer.

Inflammatory bowel disease, characterised by chronic relapsing-remitting colitis, is a significant risk factor for colorectal cancer (CRC). Previously, we showed that miR-126 functions as a tumour suppressor in CRC and is inversely correlated with tumour proliferation, metastasis and patient prognosis. In the current study, we documented a protective role for miR-126 in colitis-associated CRC (CAC) and its underlying mechanism. We detected downregulated miR-126 expression during colorectal tumorigenesis in the mouse CAC model and in specimens from patients with CRC. The deficiency of miR-126 in intestinal epithelial cells (IECs) exacerbated tumorigenesis in mice. We identified CXCL12 as a direct target of miR-126 in inhibiting the development of colitis and CAC. Moreover, miR-126 regulated the recruitment of macrophages via CXCL12 and decreased the levels of proinflammatory cytokines (IL-6, IL-12 and IL-23). In addition, IL-6 secreted by macrophages, which were regulated by cocultured transfected CRC cells, altered the proliferation and migration of colon cells. Our data suggest that miR-126 exerts an antitumour effect on CAC by regulating the crosstalk between IECs and macrophages via CXCL12-IL-6 signalling. Our study contributes to the understanding of cancer progression and suggests miR-126 as a potential therapy for CRC.

Serum Inflammatory Factor Profiles in the Pathogenesis of High-Altitude Polycythemia and Mechanisms of Acclimation to High Altitudes.

High-altitude polycythemia (HAPC) is a common aspect of chronic mountain sickness (CMS) caused by hypoxia and is the main cause of other symptoms associated with CMS. However, its pathogenesis and the mechanisms of high-altitude acclimation have not been fully elucidated. Exposure to high altitude is associated with elevated inflammatory mediators. In this study, the subjects were recruited and placed into a plain control (PC) group, plateau control (PUC) group, early HAPC (eHAPC) group, or a confirmed HAPC (cHAPC) group. Serum samples were collected, and inflammatory factors were measured by a novel antibody array methodology. The serum levels of interleukin-2 (IL-2), interleukin-3 (IL-3), and macrophage chemoattractant protein-1 (MCP-1) in the eHAPC group and the levels of interleukin-1 beta (IL-1 beta), IL-2, IL-3, tumor necrosis factor-alpha (TNF-alpha), MCP-1, and interleukin-16 (IL-16) in the cHAPC group were higher than those in the PUC group. More interestingly, the expression of IL-1 beta, IL-2, IL-3, TNF-alpha, MCP-1, and IL-16 in the PUC group showed a remarkable lower value than that in the PC group. These results suggest that these six factors might be involved in the pathogenesis of HAPC as well as acclimation to high altitudes. Altered inflammatory factors might be new biomarkers for HAPC and for high-altitude acclimation.

Roseburia intestinalis­derived flagellin ameliorates colitis by targeting miR­223­3p­mediated activation of NLRP3 inflammasome and pyroptosis.

Ulcerative colitis (UC) is a type of inflammatory bowel disease (IBD), which is a chronic, relapsing condition associated with the disorder of gut microbial communities. A previous study reported that levels of Roseburia intestinalis (R.I), a butyrate­producing bacterium, are significantly decreased in patients with IBD and exert an anti­inflammatory function in dextran sulfate sodium (DSS)­induced colitis. However, the role of R.I flagellin in UC and its underlying molecular mechanism are not yet fully understood. Therefore, a DSS­induced colitis model in C57Bl/6 mice and the LPS/ATP­induced THP­1 macrophages were treated with R.I flagellin, which were used to investigate the anti­inflammatory effects of R.I flagellin. The results demonstrated that R.I flagellin decreased colitis­associated disease activity index, colonic shortening and the pathological damage of the colon tissues in murine colitis models. Furthermore, R.I flagellin decreased the serum levels of proinflammatory cytokines and inhibited activation of the nucleotide­binding oligomerization segment­like receptor family 3 (NLRP3) inflammasome in murine colitis. R.I flagellin was also demonstrated to decrease the Gasdermin D to yield the N­terminal fragment membrane pore and inhibit inflammasome­triggered pyroptosis. In vitro analysis indicated that microRNA (miR)­223­3p was involved in the regulation of R.I flagellin on NLRP3 inflammasome activation. Taken together, the results of the present study demonstrated that R.I flagellin inhibited activation of the NLRP3 inflammasome and pyroptosis via miR­223­3p/NLRP3 signaling in macrophages, suggesting that R.I flagellin may be used as a novel probiotic product for the treatment of UC.

Fecal Microbiota Transplant via Endoscopic Delivering Through Small Intestine and Colon: No Difference for Crohn's Disease.

BACKGROUND AND AIMS: Crohn's disease (CD) is a chronic inflammatory bowel disorder associated with intestinal dysbiosis. This study aimed to determine the efficacy and safety of different methods of fecal microbiota transplantation (FMT), a potential therapy for CD. METHODS: Patients with CD were randomized to receive FMT by gastroscopy or colonoscopy; a second transplantation was performed 1 week later. Patients were assessed by clinical evaluation and serum testing (at weeks 1, 2, 4, 6, and 8) and endoscopy (8 weeks after transplantation). Fecal DNA was extracted and analyzed using the Illuminal sequencing platform. RESULTS: Of the 27 patients included in the study, clinical remission was achieved in 18 (66.7%); no significant difference was seen between the two methods. 76.9% of gastroscopy group patients and 64.3% of colonoscopy group patients experienced mild adverse events during or shortly after treatment. Microbiota diversity analyses showed that, in comparison with the donors, patients had lower operational taxonomic units (OTU; 117 vs. 258, p < 0.05) and Shannon diversity index (2.05 vs. 3.46, p < 0.05). The CD patients showed a significant increase in OTU and Shannon diversity index 2 weeks after FMT. In comparison with the donors, CD patients had lower levels of Bacteroides, Eubacterium, faecalibacterium, and Roseburia, and higher levels of Clostridium, Cronobacter, Fusobacterium, and Streptococcus. CONCLUSIONS: FMT was seen to be safe and effective in this cohort of patients with CD. No significant differences in clinical remission rate and adverse events were seen between the gastroscopy and colonoscopy groups. FMT was seen to increase the species richness in CD patients.

Systematic Review with Meta-Analysis: The Effects of Probiotics in Nonalcoholic Fatty Liver Disease.

BACKGROUND AND AIMS: Probiotics was considered as a potential therapy for nonalcoholic fatty liver disease (NAFLD) without approval and comprehensive assessment in recent years, which call for a meta-analysis. METHODS: We performed electronic and manual searches including English and Chinese databases published before April 2019, with the use of mesh term and free text of "nonalcoholic fatty liver disease" and "probiotics." Clinical trials evaluating the efficacy of probiotic therapy in NAFLD patients were included according to the eligibility criteria. With the use of random effects models, clinical outcomes were presented as weighted mean difference (WMD) with 95% confidence interval (CI), while heterogeneity and meta-regression were also assessed. RESULTS: 28 clinical trials enrolling 1555 criterion proven NAFLD patients with the use of probiotics from 4 to 28 weeks were included. Overall, probiotic therapy had beneficial effects on body mass index (WMD: -1.46, 95% CI: [-2.44, -0.48]), alanine aminotransferase (WMD: -13.40, 95% CI: [-17.03, -9.77]), aspartate transaminase (WMD: -13.54, 95% CI: [-17.86, -9.22]), gamma-glutamyl transpeptidase (WMD: -9.88, 95% CI: [-17.77, -1.99]), insulin (WMD: -1.32, 95% CI: [-2.43, -0.21]), homeostasis model assessment-insulin resistance (WMD: -0.42, 95% CI: [-0.73, -0.12]), and total cholesterol (WMD: -15.38, 95% CI: [-26.50, -4.25]), but not in fasting blood sugar, lipid profiles, or tumor necrosis factor-alpha. CONCLUSION: The systematic review and meta-analysis support that probiotics are superior to placebo in NAFLD patients and could be utilized as a common complementary therapeutic approach.

A new colitis therapy strategy via the target colonization of magnetic nanoparticle-internalized Roseburia intestinalis.

The homeostasis process in the gut tissue of humans relies on intestinal bacteria. However, the intestine is a complex structural tissue with a huge superficial area, and thus the effective application of probiotics in the treatment of Crohn's disease (CD) is still challenging. Herein, we show the feasibility of probiotic target delivery and retention using magnetic iron oxide nanoparticle-internalized Roseburia intestinalis, which can be easily directed by a magnetic field in vitro and in vivo. Subsequently, the increased colonization of this core profitable flora not only resulted in a better therapy effect than traditional intragastric administration but also altered the bacterial composition, leading to a higher diversity in microbial taxa in rats with colitis. Our findings illustrate the exciting opportunities that nanotechnology offers for alternative strategies to modulate biological systems remotely and precisely, which represent a step towards the wireless magnetic manipulation of living biological entities in microbiology.

Roseburia intestinalis supernatant ameliorates colitis induced in mice by regulating the immune response.

Inflammatory bowel disease (IBD), which includes ulcerative colitis (UC) and Crohn's disease (CD), has a complex etiology that may be associated with dysbiosis of the microbiota. Previously, our study revealed significant loss of Roseburia intestinalis from the gut of untreated patients with CD, and that R. intestinalis exerted anti­inflammatory functions in TNBS­induced colitis; however, the function of R. intestinalis supernatant is unknown. Therefore, LPS­induced macrophages, including RAW264.7 macrophages and bone marrow­derived macrophages were treated with R. intestinalis supernatant. The results indicated that R. intestinalis supernatant suppressed expression of interleukin (IL)­6 and signal transducer and activator of transcription 3 (STAT3) by macrophages. Additionally, these findings were further verified in vivo in DSS­ and TNBS­induced mouse models of colitis. It was observed that R. intestinalis supernatant ameliorated IBD colitis by reducing the number of inflammatory macrophages and Th17 cells in the colon, and by downregulating the expression of IL­6 and STAT3. Finally, the non­protein components of R. intestinalis supernatant were examined using gas chromatography­mass spectrometry analysis and identified the presence of short­chain fatty acids. In conclusion, the results of the present study indicated that R. intestinalis supernatant may regulate immune responses and ameliorate colitis.

Roseburia intestinalis inhibits oncostatin M and maintains tight junction integrity in a murine model of acute experimental colitis.

Objective: Levels of oncostatin M (OSM) and the composition of gut microbiota predict responses to anti-TNF agents used for IBD therapy. Here, the aim was to investigate the effects of Roseburia intestinalis, a gut microbiota, on OSM and on intestinal barrier in colitis. Methods: In the murine model of 3% dextran sulfate sodium (DSS)-induced colitis, we tested disease activity index (DAI), colon length, histological score and expression of tight junction (TJ) proteins (ZO-1, occludin and claudin-1), OSM, TNF-α and TLR5. In addition, a cellular model was used to examine the role of R. intestinalis during secretion of OSM by lipopolysaccharide (LPS)-induced bone marrow-derived macrophages (BMDMs) isolated from wild-type (WT) and TLR5 knockout (TLR5 KO) mice. Furthermore, we evaluated the impact of OSM on expressions of TJ proteins by Caco-2 cells. Results: R. intestinalis in DSS-induced colitis decreased DAI score (p < .001), colon length shortening (6.46 ± 0.36 cm vs 5.65 ± 0.47 cm, p = .022), histological score (2.667 ± 1.15 vs 5.33 ± 1.14, p = .018) and increased expression of TJ proteins (p < .05). In addition, R. intestinalis reduced expression of OSM (p < .05) and TNF-α (p < .05), while increasing expression of TLR5 (p < .05). Furthermore, R. intestinalis reduced secretion of OSM (p < .05) by LPS-induced BMDMs isolated from WT and TLR5 KO mice. Moreover, OSM downregulated expression of TJ proteins (p < .05) by Caco-2 cells in a concentration-dependent manner. Conclusions: These results indicate that R. intestinalis attenuates inflammation in IBD by decreasing secretion of OSM and by promoting intestinal barrier function. Taken together, the data provide insight into the role of the gut microbiota in patients with IBD who are resistant to anti-TNF therapy.

Treatment of pancreatic head cancer with obstructive jaundice by endoscopy ultrasonography-guided gastrojejunostomy: A case report and literature review.

RATIONALE: Ultrasonography-guided gastrojejunostomy (EUS-GJ) might be a safe, innovative and minimally invasive interventional treatment for patients with gastric outlet obstruction (GOO) as an alternative to the surgical approach. To date, few cases have been reported in the literature. PATIENT CONCERNS: A case of pancreatic head carcinoma with obstructive jaundice occurred in a 78-year-old man with a prior history of pancreatic head cancer. Biliary stent placement was conducted 1 year earlier. DIAGNOSES: The patient was diagnosed with pancreatic cancer, pulmonary infection, pyloric obstruction, and biliary stent implantation. INTERVENTIONS: EUS-GJ was performed. The wire and a double-balloon catheter reached the position of stenosis, then a double mushroom head bracket was released under EUS. The position was confirmed via X-ray. OUTCOMES: The symptoms of obstruction were alleviated. No recurrence of obstruction, bleeding, perforation, and other complications occurred for the following 1.5 months while he died because of whole body spread of pancreatic cancer. LESSONS: EUS-GJ may be reliable and effective for patients with GOO.

Insights into Roseburia intestinalis which alleviates experimental colitis pathology by inducing anti-inflammatory responses.

BACKGROUND AND AIM: The study aims to elucidate the anti-inflammatory effect and mechanism of Roseburia intestinalis (R. intestinalis) in Crohn's disease (CD). METHODS: 16S-rRNA genome sequencing technique is used to detect the characteristics of intestinal microbiota in untreated CD patients and healthy controls. Then the study investigates the effects of R. intestinalis on disease activity index score, intestinal pathology, the differentiation of Treg cells, and the expressions of Thymic stromal lymphopoietin (TSLP), TGF-ß and IL-10 by using TNBS colitis models. At the cellular level, the study uses LPS to stimulate Caco-2 cells to conduct inflammation models and then co-culture with R. intestinalis and detect changes of TSLP and TGF-ß. The study then uses R. intestinalis to stimulate peripheral blood mononuclear cells, and the change of Treg cells was detected. RESULTS: Genome sequencing of fecal samples from untreated CD patients (n = 10) revealed decreases in the abundance and diversity of intestinal microbiota, including R. intestinalis. Moreover, R. intestinalis reduced disease activity index scores, colon shortening, intestinal mucosal epithelial injury, and mucosal lymphocyte infiltration in a colitis mice model. It suppressed intestinal inflammation by increasing Treg cell numbers and expression of the anti-inflammatory cytokines TSLP, TGF-ß, and interleukin-10 (P < 0.05). R. intestinalis also increased secretion of TSLP and TGF-ß in lipopolysaccharide-treated Caco-2 cells. CONCLUSION: These findings suggest that R. intestinalis suppresses CD pathogenesis by inducing anti-inflammatory responses.

Knockdown of long non-coding RNA MAP3K20 antisense RNA 1 inhibits gastric cancer growth through epigenetically regulating miR-375.

Emerging evidence has demonstrated that long noncoding RNAs (lncRNAs) play a critical role in tumorigenesis of gastric cancer. LncRNA MAP3K20 antisense RNA 1 (MLK7-AS1) has been identified as one of gastric cancer-specific lncRNAs. However, its precise role in gastric cancer remains unknown. In this study, we found that lncRNA MLK7-AS1 was significantly increased in gastric cancer tissues compared with in adjacent tissues. Gastric cancer patients with high MLK7-AS1 expression had a shorter survival and poorer prognosis. By loss-function assay, we demonstrated that knockdown of MLK7-AS1 inhibited cell proliferation and induced apoptosis in HGC27and MKN-45 cells. Furthermore, we identified miR-375 as a target of MLK7-AS1. MLK7-AS1 interacted with Dnmt1 and recruited it to miR-375 promotor, hyper-methylating miR-375 promotor and repressing miR-375 expression. Taken together, our findings demonstrate that knockdown of MLK7-AS1 by siRNA inhibits gastric cancer growth by epigenetically regulating miR-375. Thus, MLK7-AS1 may be a useful prognostic marker and therapeutic target for gastric cancer patients.

Update on intestinal microbiota in Crohn's disease 2017: Mechanisms, clinical application, adverse reactions, and outlook.

The pathogenesis of Crohn's disease (CD) is complex, and it is thought to be associated with the environment, immune, hereditary, microbe, and other factors. If the balance between the host and the intestinal microbes in CD patients was broken, immune-inflammatory response of susceptible individuals might be triggered. Probiotics could improve the intestinal microbial flora balance and treat human effectively. There are several new mechanisms that might explain the role of probiotics. Fecal microbiota transplantation (FMT) is becoming more and more attractive in treating a large amount of digestive system diseases that are related to the dysbiosis of intestinal microbiota. FMT has been widely used in recurrent Clostridium difficile infection. More and more attention has been paid on the clinical application of FMT in CD, while the exact mechanism is still a mystery. So in this review, we explore the mechanism, clinical application, and adverse reactions of intestinal microbiota in CD so that we can use the tool to cure more diseases. Enteric microbiota leads to new therapeutic strategies for CD.

Targeting of the leukemia microenvironment by c(RGDfV) overcomes the resistance to chemotherapy in acute myeloid leukemia in biomimetic polystyrene scaffolds.

The bone marrow microenvironment provides a relative sanctuary from cytotoxic drugs for leukemia cells. The present niche models concentrate on a two-dimensional (2D) co-culture system in vitro, which does not imitate the in vivo environment, while the 3D scaffolds are more reflective of this. Osteopontin (Opn) secreted by bone marrow osteoblasts, may participate in protecting leukemia cells from apoptosis by binding to its receptor αvß3, which can be expressed on the surface of the leukemia MV4-11 cell line. However, the association between the Opn/αvß3 axis and leukemia cells is unknown. In the present study, experiments were conducted on 3D polystyrene scaffolds coated with osteoblasts and leukemia cells. The cells were exposed to cyclo(Arg-Gly-Asp-d-Phe-Val) [c(RGDfV)] (35 nmol/ml), which blocks αvß3, for a period of 24 h. Cytarabine was applied 24 h later. The adhesion, migration and apoptosis rates, and the cell cycle of the leukemia cells were analyzed after incubation for 24 and 48 h. In contrast to the 2D culture system, the stromal cells in the scaffolds secreted significantly more alkaline phosphatase and Opn (P<0.05). c(RGDfV) disrupted the adhesion and migration between the tumor cells and the matrix, induced the leukemia cells to leave the protective microenvironment and increased their sensitivity to cell cycle-dependent agents (P<0.05). In summary, the data certified that the 3D scaffolds are suitable for the growth of cells, and that c(RGDfV) inhibits the adhesion and migration abilities of leukemia cells in the endosteal niche. Therefore, blocking the function of Opn may be beneficial in the treatment of acute myeloid leukemia.

MicroRNA-126 inhibits colon cancer cell proliferation and invasion by targeting the chemokine (C-X-C motif) receptor 4 and Ras homolog gene family, member A, signaling pathway.

MicroRNA-126 (miR-126) suppresses the migration, proliferation and invasion of colon cancer cells. However, the underlying mechanisms of miR-126 in colon cancer have not been fully elucidated. In this study, in vivo experiments revealed that miR-126 inhibits colon cancer growth and metastasis. Furthermore, miR-126 was down-regulated in human colon cancer tissue, and its expression was inversely correlated with TNM stage and metastasis of patients. Low level of miR-126 identified patients with poor prognosis. And we found that miR-126 expression was negatively correlated with the expression levels of chemokine (C-X-C motif) receptor 4 (CXCR4) and components of signaling pathway of Ras homolog gene family, member A (RhoA) in vitro and in vivo. Moreover, we verified that miR-126 negatively regulated CXCR4 and RhoA signaling in vitro. In addition, either in miR-126-overexpressing or in miR- 126-silenced colon cancer cells, the restoration of CXCR4 could significantly reverse the proliferation and invasion, as well as abolish the effects of miR-126 on RhoA signaling pathway. Collectively, these results demonstrated that miR-126 acts as a tumor suppressor by inactivating RhoA signaling via CXCR4 in colon cancer. And miR-126 may serve as a prognostic marker for monitoring and treating colon cancer.

Integrin alphavbeta3 enhances ß-catenin signaling in acute myeloid leukemia harboring Fms-like tyrosine kinase-3 internal tandem duplication mutations: implications for microenvironment influence on sorafenib sensitivity.

Binding of leukemia cells to the bone marrow extracellular matrix (ECM) through integrins might influence drug response and the survival of acute myeloid leukemia (AML). However, the functions of integrin in AML are needed to be clarified. Data from The Cancer Genome Atlas (TCGA) were retrieved and integrin ß3 (ITGB3) expression and prognostic significance for AML were analyzed. Integrin alphavbeta3 (αvß3) in sorafenib sensitivity and signaling pathway of FLT3-ITD AML cells was evaluated in vitro. The level of ITGB3 expression was positively correlated with risk stratification and prognosis of AML patients, especially in cytogenetic-normal patients with Fms-like tyrosine kinase-3 internal tandem duplication (FLT3-ITD) mutation. Integrin αvß3 decreased sorafenib sensitivity when co-culture of MV4-11 cells and bone marrow stromal cells (BMSCs), and it is crucial for osteopontin (OPN) induced sorafenib insensitivity in FLT3-ITD mutated AML cells. Mechanically, αvß3 enhance ß-catenin activation through phosphatidylinositol 3-kinase (PI3K)/Akt/Glycogen synthase kinase-3 beta (GSK3ß) pathway. Moreover, genetic inhibition of ß-catenin by shRNA could increase sorafenib sensitivity in MV4-11 cells. Taken together, our study revealed a novel mechanism in microenvironment influence on sorafenib sensitivity in AML with FLT3-ITD mutation that was caused by activating integrin αvß3/PI3K/Akt/GSK3ß/ß-catenin pathway. Integrin αvß3/ß-catenin could be considered as a new therapeutic target for AML especially for FLT3-ITD mutated AML.

AMD3100 and G-CSF disrupt the cross-talk between leukemia cells and the endosteal niche and enhance their sensitivity to chemotherapeutic drugs in biomimetic polystyrene scaffolds.

BACKGROUND: The multidrug resistance of leukemia cells is closely related to the microenvironment. The present leukemia microenvironment models focus on two-dimensional co-culture system in vitro which does not mimic the in vivo cell growth, while the 3D polystyrene (PS) scaffolds have the advantage. Stromal cell derived factor-1 may be involved in the shielding of endosteal niche from leukemia cells by binding to its receptor CXCR4, but the relationship between SDF-1/CXCR4 axis and leukemia cells is unclear. DESIGN AND METHODS: The experiments were built on the 3D PS scaffolds coated with osteoblasts. Stromal cells and MV4-11 cells were plated on the scaffolds. Then G-CSF, AMD3100 and cytarabine were added. Adhesive rate, SDF-1 level, migration state, apoptosis rate, and cell cycle of leukemia cells were observed after incubation at 24h and 48h. RESULTS: G-CSF decreased the level of SDF-1 and inhibited the expression of CXCR4 and promoted stationary phase leukemia cells to enter the mitotic phase and enhanced the killing effect of chemotherapeutic drugs. AMD3100 disrupted the interaction between tumors and matrix, mobilized the leukemia cells to keep away from the protective microenvironment and strengthened the cytotoxic effect of Ara-C. The combination of G-CSF and AMD3100 had stronger effects on killing the leukemia cells induced by Ara-C. CONCLUSION: It demonstrates that AMD3100 and G-CSF may inhibit adhesion and migration abilities of leukemia cells with the bone marrow niche. Both of them inhibit the role of SDF-1/CXCR4 directly or indirectly. Thus inhibiting SDF-1/CXCR4 axis may be helpful to the treatment of refractory AML.

Are there any new insights for G-CSF and/or AMD3100 in chemotherapy of haematological malignants?

AML is a common life-threatening blood system malignancy. The treatment of AML continues to face greater challenges. An abnormal haematopoietic niche with high adhesion and proliferation might be the root cause of resistance and relapse. Most leukaemia cells are stored in the endosteal niche and recess in the G0 phase, and they are not sensitive to varieties of radiotherapies and chemotherapies. G-CSF and AMD3100 are increasingly used in priming chemotherapy. G-CSF can promote leukaemia cells to the cell cycle, which improves the complete remission rate of leukaemia patients. AMD3100, the novel CXCR4 antagonist, could also potentially promote leukaemia cells to cell cycle and improve the susceptibility of leukaemia cells to chemotherapeutic agents. The combination of them enhances anti-leukaemia effect. So in this review, we explore the function of G-CSF and/or AMD3100 in the priming chemotherapy of haematological malignants.