Senescence Defines a Distinct Subset of Myofibroblasts That Orchestrates Immunosuppression in Pancreatic Cancer.

Pancreatic ductal adenocarcinoma (PDAC) therapeutic resistance is largely attributed to a unique tumor microenvironment embedded with an abundance of cancer-associated fibroblasts (CAF). Distinct CAF populations were recently identified, but the phenotypic drivers and specific impact of CAF heterogeneity remain unclear. In this study, we identify a subpopulation of senescent myofibroblastic CAFs (SenCAF) in mouse and human PDAC. These SenCAFs are a phenotypically distinct subset of myofibroblastic CAFs that localize near tumor ducts and accumulate with PDAC progression. To assess the impact of endogenous SenCAFs in PDAC, we used an LSL-KRASG12D;p53flox;p48-CRE;INK-ATTAC (KPPC-IA) mouse model of spontaneous PDAC with inducible senescent cell depletion. Depletion of senescent stromal cells in genetic and pharmacologic PDAC models relieved immune suppression by macrophages, delayed tumor progression, and increased responsiveness to chemotherapy. Collectively, our findings demonstrate that SenCAFs promote PDAC progression and immune cell dysfunction. Significance: CAF heterogeneity in PDAC remains poorly understood. In this study, we identify a novel subpopulation of senescent CAFs that promotes PDAC progression and immunosuppression. Targeting CAF senescence in combination therapies could increase tumor vulnerability to chemo or immunotherapy. See related article by Ye et al., p. 1302.

"RIPping" off Pancreas Cancer's Blockage of Immune Surveillance.

SUMMARY: MHC-I downregulation is correlated with immunotherapy resistance in PDAC, but efficient strategies to increase cell-surface MHC-I are still lacking. This study by Sang, Zhou, Chen, Yu, and colleagues identified inhibition of tumor-intrinsic RIPK2 as a pharmacologic target to block the degradation of MHC-I on tumor cells and improved PDAC responses to anti-PD-1 immunotherapy. See related article by Sang et al., p. 326 (1) .

Epigenetic regulation during cancer transitions across 11 tumour types.

Chromatin accessibility is essential in regulating gene expression and cellular identity, and alterations in accessibility have been implicated in driving cancer initiation, progression and metastasis1-4. Although the genetic contributions to oncogenic transitions have been investigated, epigenetic drivers remain less understood. Here we constructed a pan-cancer epigenetic and transcriptomic atlas using single-nucleus chromatin accessibility data (using single-nucleus assay for transposase-accessible chromatin) from 225 samples and matched single-cell or single-nucleus RNA-sequencing expression data from 206 samples. With over 1 million cells from each platform analysed through the enrichment of accessible chromatin regions, transcription factor motifs and regulons, we identified epigenetic drivers associated with cancer transitions. Some epigenetic drivers appeared in multiple cancers (for example, regulatory regions of ABCC1 and VEGFA; GATA6 and FOX-family motifs), whereas others were cancer specific (for example, regulatory regions of FGF19, ASAP2 and EN1, and the PBX3 motif). Among epigenetically altered pathways, TP53, hypoxia and TNF signalling were linked to cancer initiation, whereas oestrogen response, epithelial-mesenchymal transition and apical junction were tied to metastatic transition. Furthermore, we revealed a marked correlation between enhancer accessibility and gene expression and uncovered cooperation between epigenetic and genetic drivers. This atlas provides a foundation for further investigation of epigenetic dynamics in cancer transitions.

TNF-α promotes CXCL-1/8 production in keratinocytes by downregulating galectin-3 through NF-κB and hsa-miR-27a-3p pathway to contribute psoriasis development.

OBJECTIVE: Treatment with TNF-α inhibitors improve psoriasis with minimize/minor neutrophils infiltration and CXCL-1/8 expression in psoriatic lesions. However, the fine mechanism of TNF-α initiating psoriatic inflammation by tuning keratinocytes is unclear. Our previous research identified the deficiency of intracellular galectin-3 was sufficient to promote psoriasis inflammation characterized by neutrophil accumulation. This study aims to investigate whether TNF-α participated in psoriasis development through dysregulating galectin-3 expression. METHODS: mRNA levels were assessed through quantitative real-time PCR. Flow cytometry was used to detect cell cycle/apoptosis. Western blot was used to evaluate the activation of the NF-κB signaling pathway. HE staining and immunochemistry were used to detect epidermal thickness and MPO expression, respectively. Specific small interfering RNA (siRNA) was used to knock down hsa-miR-27a-3p while plasmids transfection was used to overexpress galectin-3. Further, the multiMiR R package was utilized to predict microRNA-target interaction. RESULTS AND DISCUSSION: We found that TNF-α stimulation altered cell proliferation and differentiation and promoted the production of psoriasis-related inflammatory mediators along with the inhibition of galectin-3 expression in keratinocytes. Supplement of galectin-3 could counteract the rise of CXCL-1/8 but not the other phenotypes of keratinocytes induced by TNF-α. Mechanistically, inhibition of the NF-κB signaling pathway could counteract the decrease of galectin-3 and the increase of hsa-miR-27a-3p expression whereas silence of hsa-miR-27a-3p could counteract the decrease of galectin-3 expression induced by TNF-α treatment in keratinocytes. Intradermal injection of murine anti-CXCL-2 antibody greatly alleviated imiquimod-induced psoriasis-like dermatitis. CONCLUSION: TNF-α initiates psoriatic inflammation by increasing CXCL-1/8 in keratinocytes mediated by the axis of NF-κB-hsa-miR-27a-3p-galectin-3 pathway.

Context-dependent activation of STING-interferon signaling by CD11b agonists enhances anti-tumor immunity.

Chronic activation of inflammatory pathways and suppressed interferon are hallmarks of immunosuppressive tumors. Previous studies have shown that CD11b integrin agonists could enhance anti-tumor immunity through myeloid reprograming, but the underlying mechanisms remain unclear. Herein we find that CD11b agonists alter tumor-associated macrophage (TAM) phenotypes by repressing NF-κB signaling and activating interferon gene expression simultaneously. Repression of NF-κB signaling involves degradation of p65 protein and is context independent. In contrast, CD11b agonism induces STING/STAT1 pathway-mediated interferon gene expression through FAK-mediated mitochondrial dysfunction, with the magnitude of induction dependent on the tumor microenvironment and amplified by cytotoxic therapies. Using tissues from phase I clinical studies, we demonstrate that GB1275 treatment activates STING and STAT1 signaling in TAMs in human tumors. These findings suggest potential mechanism-based therapeutic strategies for CD11b agonists and identify patient populations more likely to benefit.

Stromal and therapy-induced macrophage proliferation promotes PDAC progression and susceptibility to innate immunotherapy.

Tumor-associated macrophages (TAMs) are abundant in pancreatic ductal adenocarcinomas (PDACs). While TAMs are known to proliferate in cancer tissues, the impact of this on macrophage phenotype and disease progression is poorly understood. We showed that in PDAC, proliferation of TAMs could be driven by colony stimulating factor-1 (CSF1) produced by cancer-associated fibroblasts. CSF1 induced high levels of p21 in macrophages, which regulated both TAM proliferation and phenotype. TAMs in human and mouse PDACs with high levels of p21 had more inflammatory and immunosuppressive phenotypes. p21 expression in TAMs was induced by both stromal interaction and/or chemotherapy treatment. Finally, by modeling p21 expression levels in TAMs, we found that p21-driven macrophage immunosuppression in vivo drove tumor progression. Serendipitously, the same p21-driven pathways that drive tumor progression also drove response to CD40 agonist. These data suggest that stromal or therapy-induced regulation of cell cycle machinery can regulate both macrophage-mediated immune suppression and susceptibility to innate immunotherapy.

Stromal Reprogramming by FAK Inhibition Overcomes Radiation Resistance to Allow for Immune Priming and Response to Checkpoint Blockade.

The effects of radiotherapy (RT) on tumor immunity in pancreatic ductal adenocarcinoma (PDAC) are not well understood. To better understand if RT can prime antigen-specific T-cell responses, we analyzed human PDAC tissues and mouse models. In both settings, there was little evidence of RT-induced T-cell priming. Using in vitro systems, we found that tumor-stromal components, including fibroblasts and collagen, cooperate to blunt RT efficacy and impair RT-induced interferon signaling. Focal adhesion kinase (FAK) inhibition rescued RT efficacy in vitro and in vivo, leading to tumor regression, T-cell priming, and enhanced long-term survival in PDAC mouse models. Based on these data, we initiated a clinical trial of defactinib in combination with stereotactic body RT in patients with PDAC (NCT04331041). Analysis of PDAC tissues from these patients showed stromal reprogramming mirroring our findings in genetically engineered mouse models. Finally, the addition of checkpoint immunotherapy to RT and FAK inhibition in animal models led to complete tumor regression and long-term survival. SIGNIFICANCE: Checkpoint immunotherapeutics have not been effective in PDAC, even when combined with RT. One possible explanation is that RT fails to prime T-cell responses in PDAC. Here, we show that FAK inhibition allows RT to prime tumor immunity and unlock responsiveness to checkpoint immunotherapy. This article is highlighted in the In This Issue feature, p. 2711.

Etanercept treatment of Stevens-Johnson syndrome and toxic epidermal necrolysis.

BACKGROUND: Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) is a severe cutaneous adverse reaction to drugs with considerable morbidity and mortality. Immunomodulators for SJS/TEN including systemic corticosteroids and intravenous immunoglobulin (IVIG) have been widely used in clinical practice. Emerging evidence suggested the therapeutic effects of tumor necrosis factor-α antagonists on SJS/TEN. OBJECTIVE: To compare the efficacy and safety of IVIG and systemic steroids in conjunction with or without etanercept, a tumor necrosis factor-α inhibitor, for patients with SJS/TEN. METHODS: We undertook a retrospective review of 41 patients with SJS/TEN admitted to our institution from 2015 to February 2021. A total of 25 patients with integrated data were involved in this study, of which 14 patients were treated with IVIG and corticosteroids and 11 were in addition given etanercept. The clinical characteristics, duration of hospitalization, exposure time to high-dose steroids, and the total amount of systemic steroids were analyzed. RESULTS: In comparison to conventional therapy, conjunction with etanercept reduced the duration of hospitalization (13.5 vs 19.0 days; P = .01), the exposure time of high-dose steroids (7.1 vs 14.9 days; P = .01), and the overall amount of systemic steroid (925 mg vs 1412.5 mg; P = .03) in patients with SJS/TEN. No pronounced adverse effects were observed within 6 months of follow-up after the treatment. CONCLUSION: The add-in of etanercept at the time of initiating conventional therapy could be a superior option to accelerate disease recovery and reduce the high dose and total amount of systemic steroids without pronounced adverse events in patients with SJS/TEN.

IRAK4 Signaling Drives Resistance to Checkpoint Immunotherapy in Pancreatic Ductal Adenocarcinoma.

BACKGROUND & AIMS: Checkpoint immunotherapy is largely ineffective in pancreatic ductal adenocarcinoma (PDAC). The innate immune nuclear factor (NF)-κB pathway promotes PDAC cell survival and stromal fibrosis, and is driven by Interleukin-1 Receptor Associated Kinase-4 (IRAK4), but its impact on tumor immunity has not been directly investigated. METHODS: We interrogated The Cancer Genome Atlas data to identify the correlation between NF-κB and T cell signature, and a PDAC tissue microarray (TMA) to correlate IRAK4 activity with CD8+ T cell abundance. We performed RNA sequencing (RNA-seq) on IRAK4-deleted PDAC cells, and single-cell RNA-seq on autochthonous KPC (p48-Cre/TP53f/f/LSL-KRASG12D) mice treated with an IRAK4 inhibitor. We generated conditional IRAK4-deleted KPC mice and complementarily used IRAK4 inhibitors to determine the impact of IRAK4 on T cell immunity. RESULTS: We found positive correlation between NF-κB activity, IRAK4 and T cell exhaustion from The Cancer Genome Atlas. We observed inverse correlation between phosphorylated IRAK4 and CD8+ T cell abundance in a PDAC tissue microarray. Loss of IRAK4 abrogates NF-κB activity, several immunosuppressive factors, checkpoint ligands, and hyaluronan synthase 2, all of which drive T cell dysfunction. Accordingly, conditional deletion or pharmacologic inhibition of IRAK4 markedly decreased tumor desmoplasia and increased the abundance and activity of infiltrative CD4+ and CD8+ T cells in KPC tumors. Single-cell RNA-seq showed myeloid and fibroblast reprogramming toward acute inflammatory responses following IRAK4 inhibition. These changes set the stage for successful combination of IRAK4 inhibitors with checkpoint immunotherapy, resulting in excellent tumor control and markedly prolonged survival of KPC mice. CONCLUSION: IRAK4 drives T cell dysfunction in PDAC and is a novel, promising immunotherapeutic target.

Blockade of IDO-Kynurenine-AhR Axis Ameliorated Colitis-Associated Colon Cancer via Inhibiting Immune Tolerance.

BACKGROUND & AIMS: Chronic inflammation in colon section is associated with an increased risk of colorectal cancer (CRC). Proinflammatory cytokines were produced in a tumor microenvironment and correlated with poor clinical outcome. Tumor-infiltrating T cells were reported to be greatly involved in the development of colon cancer. In this study, we demonstrated that kynurenine (Kyn), a metabolite catalyzed by indoleamine 2,3-dioxygenase (IDO), was required for IDO-mediated T cell function, and adaptive immunity indeed played a critical role in CRC. METHODS: Supernatant of colon cancer cells was used to culture activated T cells and mice spleen lymphocytes, and the IDO1-Kyn-aryl hydrocarbon (AhR) receptor axis was determined in vitro. In vivo, an azoxymethane (AOM)/dextran sodium sulfate (DSS)-induced CRC model was established in IDO-/-, Rag1-/-, and wild-type mice, and tumor-associated T lymphocyte infiltration and Kyn/AhR signaling pathway changes were measured in each group. RESULTS: Kyn promoted AhR nuclear translocation increased the transcription of Foxp3, a marker of regulatory T cells (Tregs), through improving the interaction between AhR and Foxp3 promoter. Additionally, compared WT mice, IDO-/- mice treated with AOM/DSS exhibited fewer and smaller tumor burdens in the colon, with less Treg and more CD8+ T cells infiltration, while Kyn administration abolished this regulation. Rag1-/- mice were more sensitive to AOM/DSS-induced colitis-associated colon cancer (CRC) compared with the wild-type mice, suggesting that T cell-mediated adaptive immunity indeed played a critical role in CRC. CONCLUSIONS: We demonstrated that inhibition of IDO diminished Kyn/AhR-mediated Treg differentiation and could be an effective strategy for the prevention and treatment of inflammation-related colon cancer.

Rethinking immune checkpoint blockade: 'Beyond the T cell'.

The clinical success of immune checkpoint inhibitors has highlighted the central role of the immune system in cancer control. Immune checkpoint inhibitors can reinvigorate anti-cancer immunity and are now the standard of care in a number of malignancies. However, research on immune checkpoint blockade has largely been framed with the central dogma that checkpoint therapies intrinsically target the T cell, triggering the tumoricidal potential of the adaptive immune system. Although T cells undoubtedly remain a critical piece of the story, mounting evidence, reviewed herein, indicates that much of the efficacy of checkpoint therapies may be attributable to the innate immune system. Emerging research suggests that T cell-directed checkpoint antibodies such as anti-programmed cell death protein-1 (PD-1) or programmed death-ligand-1 (PD-L1) can impact innate immunity by both direct and indirect pathways, which may ultimately shape clinical efficacy. However, the mechanisms and impacts of these activities have yet to be fully elucidated, and checkpoint therapies have potentially beneficial and detrimental effects on innate antitumor immunity. Further research into the role of innate subsets during checkpoint blockade may be critical for developing combination therapies to help overcome checkpoint resistance. The potential of checkpoint therapies to amplify innate antitumor immunity represents a promising new field that can be translated into innovative immunotherapies for patients fighting refractory malignancies.

Mesenchymal Stem Cells Activate the MEK/ERK Signaling Pathway and Enhance DNA Methylation via DNMT1 in PBMC from Systemic Lupus Erythematosus.

The defective MEK/ERK signaling pathway and downstream hypomethylation pattern of lymphocytes are crucial for the pathogenesis of systemic lupus erythematosus (SLE). However, the role that the mesenchymal stem cells play in the MEK/ERK signaling pathway and DNA methylation of peripheral blood mononuclear cells (PBMC) from SLE patients remains unknown. In this study, we found that the MEK/ERK signaling pathway of PBMC from SLE patients was activated after the coculture with bone marrow-derived mesenchymal stem cells (BM-MSC) compared with that from the control group. In addition, the expression level of DNA methyltransferase 1 (DNMT1) increased while the levels of CD70, integrin, alpha L (ITGAL), selectin-l, and IL-13 were reduced in PBMC from SLE patients. However, no obvious effect of BM-MSC on PBMC from healthy controls was observed. These findings revealed that BM-MSC might downregulate the expression of methylation-sensitive genes and then suppress the autoactivated PBMC via the MEK/ERK signaling pathway. And it may be one of the mechanisms that BM-MSC ameliorated SLE.

Correction: Macrophage-derived CCL5 facilitates immune escape of colorectal cancer cells via the p65/STAT3-CSN5-PD-L1 pathway.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Development of resistance to FAK inhibition in pancreatic cancer is linked to stromal depletion.

OBJECTIVE: We investigated how pancreatic cancer developed resistance to focal adhesion kinase (FAK) inhibition over time. DESIGN: Pancreatic ductal adenocarcinoma (PDAC) tumours from KPC mice (p48-CRE; LSL-KRasG12D/wt; p53flox/wt) treated with FAK inhibitor were analysed for the activation of a compensatory survival pathway in resistant tumours. We identified pathways involved in the regulation of signal transducer and activator of transcription 3 (STAT3) signalling on FAK inhibition by gene set enrichment analysis and verified these outcomes by RNA interference studies. We also tested combinatorial approaches targeting FAK and STAT3 in syngeneic transplantable mouse models of PDAC and KPC mice. RESULTS: In KPC mice, the expression levels of phosphorylated STAT3 (pSTAT3) were increased in PDAC cells as they progressed on FAK inhibitor therapy. This progression corresponded to decreased collagen density, lowered numbers of SMA+ fibroblasts and downregulation of the transforming growth factor beta (TGF-ß)/SMAD signalling pathway in FAK inhibitor-treated PDAC tumours. Furthermore, TGF-ß production by fibroblasts in vitro drives repression of STAT3 signalling and enhanced responsiveness to FAK inhibitor therapy. Knockdown of SMAD3 in pancreatic cancer cells abolished the inhibitory effects of TGF-ß on pSTAT3. We further found that tumour-intrinsic STAT3 regulates the durability of the antiproliferative activity of FAK inhibitor, and combinatorial targeting of FAK and Janus kinase/STAT3 act synergistically to suppress pancreatic cancer progression in mouse models. CONCLUSION: Stromal depletion by FAK inhibitor therapy leads to eventual treatment resistance through the activation of STAT3 signalling. These data suggest that, similar to tumour-targeted therapies, resistance mechanisms to therapies targeting stromal desmoplasia may be critical to treatment durability.

FoxO3 reverses 5-fluorouracil resistance in human colorectal cancer cells by inhibiting the Nrf2/TR1 signaling pathway.

5-fluorouracil (5-FU) is widely used in chemotherapy for colorectal cancer (CRC), but a high rate of chemoresistance reduces its effectiveness in clinical treatment. We found remarkably decreased expression of forkhead box 3 (FoxO3) protein, a tumor inhibitor, in 5-FU-resistant SW620 and HCT-8 (SW620/5-FU and HCT-8/5-FU) cells. Moreover, FoxO3 overexpression sensitized SW620/5-FU and HCT-8/5-FU cells to 5-FU. Mechanistically, FoxO3 inhibited the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway by directly binding to Keap1 promoter. Thioredoxin reductase 1 (TR1), a pivotal target gene of Nrf2, was observed to promote 5-FU resistance by reducing intracellular ROS levels. Clinical data also revealed that significant upregulation of TR1 was associated with poor outcome in CRC patients. Auranofin (AUR), a FoxO3 agonist and TR1 inhibitor, enhanced the sensitivity of HCT-8/5-FU and SW620/5-FU cells to 5-FU in vitro and in vivo. Taken together, our results suggest that FoxO3 could reverse 5-FU resistance in CRC via inhibiting the Nrf2/TR1 signaling pathway, and increasing the level of intracellular reactive oxygen species. Chemotherapeutic agents targeting FoxO3 and/or TR1, including AUR, might be promising adjuvant sensitizers to reverse chemoresistance in 5-FU-resistant CRC.

Macrophage-derived CCL5 facilitates immune escape of colorectal cancer cells via the p65/STAT3-CSN5-PD-L1 pathway.

Infiltrated macrophages are an important constituent of the tumor microenvironment and play roles in tumor initiation and progression by promoting immune evasion. However, the molecular mechanism by which macrophage-derived cytokines foster immune escape of colorectal cancer (CRC) is unclear. Here, we demonstrated that macrophage infiltration induced by lipopolysaccharide (LPS) or a high-cholesterol diet (HCD) significantly promoted CRC growth. Similarly, LPS and poly (I:C) remarkably increased the volume of CT26 cell allograft tumors. C-C motif chemokine ligand 5 (CCL5), which is secreted by macrophages, inhibited T-cell-mediated killing of HT29 cells and promoted immune escape by stabilizing PD-L1 in vitro and in vivo. Mechanistically, CCL5 resulted in formation of nuclear factor kappa-B p65/STAT3 complexes, which bound to the COP9 signalosome 5 (CSN5) promoter, leading to its upregulation. Moreover, CSN5 modulated the deubiquitination and stability of PD-L1. High expression of CSN5 in CRC was associated with significantly shorter survival. Furthermore, compound-15 was identified as an inhibitor of CSN5, and destabilized PD-L1 to alleviate the tumor burden. Our results suggest that the novel CCL5-p65/STAT3-CSN5-PD-L1 signaling axis is significantly activated by LPS or HCD-driven macrophage infiltration in an animal model of CRC, which likely has therapeutic and prognostic implications for human cancers.

Inhibitory effects of ursolic acid from Bushen Yijing Formula on TGF-ß1-induced human umbilical vein endothelial cell fibrosis via AKT/mTOR signaling and Snail gene.

The present study aimed to investigate the functional components from Bushen Yijing Formula and their inhibition of endothelial-mesenchymal transition (EndMT) and fibrosis in human umbilical vascular endothelial cells (HUVECs). HUVEC fibrosis was induced by treatment of transforming growth factor ß (TGF-ß) as the cellular model. Expression of EndMT biomarker gene and cofactors were determined by quantitative real-time-PCR, western blotting, and immunofluorescence. Angiogenesis capacity of vein endothelial cells was evaluated using tube formation assay. Ursolic acid and drug-contained serum ameliorated EndMT biomarker gene expression changes and angiogenesis capacity suppression induced by TGF-ß treatment. Slug, Snail, and Twist gene expression and phosphorylation of mammalian target of rapamycin (mTOR) and AKT altered by TGF-ß in HUVECs were suppressed by ursolic acid and drug-contained serum. Treatment with the mTOR signaling pathway inhibitor, rapamycin, inhibited the phosphorylation of mTOR and AKT, decreased Snail and Vimentin protein levels, and increased VE-cad protein levels. Overexpression of Snail gene promoted expression of EndMT-related genes and suppressed angiogenesis in HUVECs, which were attenuated by application of ursolic acid and drug-contained serum. Ursolic acid from Bushen Yijing Formula inhibits human umbilical vein endothelial cell EndMT and fibrosis, mediated by AKT/mTOR signaling and Snail gene expression.

Glutamate alleviates intestinal injury, maintains mTOR and suppresses TLR4 and NOD signaling pathways in weanling pigs challenged with lipopolysaccharide.

This experiment aimed to explore whether glutamate (Glu) had beneficial effects on intestinal injury caused by Escherichia coli LPS challenge via regulating mTOR, TLRs, as well as NODs signaling pathways. Twenty-four piglets were allotted to 4 treatments including: (1) control group; (2) LPS group; (3) LPS + 1.0% Glu group; (4) LPS + 2.0% Glu group. Supplementation with Glu increased jejunal villus height/crypt depth ratio, ileal activities of lactase, maltase and sucrase, and RNA/DNA ratio and protein abundance of claudin-1 in jejunum and ileum. In addition, the piglets fed Glu diets had higher phosphorylated mTOR (Ser2448)/total mTOR ratio in jejunum and ileum. Moreover, Glu decreased TNF-α concentration in plasma. Supplementation with Glu also decreased mRNA abundance of jejunal TLR4, MyD88, IRAK1, TRAF6, NOD2 and increased mRNA abundance of ileal Tollip. These results indicate that Glu supplementation may be closely related to maintaining mTOR and inhibiting TLR4 and NOD signaling pathways, and concomitant improvement of intestinal integrity under an inflammatory condition.

Ginsenoside Rd ameliorates colitis by inducing p62-driven mitophagy-mediated NLRP3 inflammasome inactivation in mice.

Previous studies reported that Ginsenoside Rd (Rd) had anti-inflammatory and anti-cancer effects. However, the molecular mechanism underlying the inhibition effect of Rd on colitis in mice hasn't been clarified clearly. Here, in our study, we detected the effects of Rd on dextran sulfate sodium (DSS)-induced murine colitis, and found that oral administration of Rd dose-dependently alleviated DSS-induced body weight loss, colon length shortening and colonic pathological damage with lower myeloperoxidase (MPO) and inducible nitric oxide synthase (iNOS) activities and higher glutathione level. In addition, the production of pro-inflammatory cytokines (IL-1ß, TNF-a and IL-6) in both serum and colonic tissues were significantly down-regulated by Rd administration. The activation of NLRP3 inflammasome was also suppressed in Rd-treated group, resulting in reduced caspase-1 production and IL-1ß secretion. In vitro, Rd remarkably inhibited NLRP3 inflammasome activation which was mostly dependent on the mitochondrial translocation of p62 and mitophagy. Importantly, Rd-driven inhibition of the NLRP3 inflammasome was significantly blocked by various autophagy inhibitors. Furthermore, upregulation of AMPK/ULK1 signaling pathway accounted for Rd-induced autophagy, which was also seen in vivo. In conclusion, our results demonstrated the function of Rd on the inhibition NLRP3 inflammasome and its potential application for the treatment of NLRP3-associated diseases.

1-L-MT, an IDO inhibitor, prevented colitis-associated cancer by inducing CDC20 inhibition-mediated mitotic death of colon cancer cells.

Indoleamine 2,3-dioxygenase 1 (IDO1), known as IDO, catabolizes tryptophan through kynurenine pathway, whose activity is correlated with impaired clinical outcome of colorectal cancer. Here we showed that 1-L-MT, a canonical IDO inhibitor, suppressed proliferation of human colorectal cancer cells through inducing mitotic death. Our results showed that inhibition of IDO decreased the transcription of CDC20, which resulted in G2/M cycle arrest of HCT-116 and HT-29. Furthermore, 1-L-MT induced mitochondria injuries and caused apoptotic cancer cells. Importantly, 1-L-MT protected mice from azoxymethane (AOM)/dextran sodium sulfate (DSS)-induced colon carcinogenesis, with reduced mortality, tumor number and size. What is more, IDO1-/- mice exhibited fewer tumor burdens and reduced proliferation in the neoplastic epithelium, while, 1-L-MT did not exhibit any further protective effects on IDO-/- mice, confirming the critical role of IDO and the protective effect of 1-L-MT-mediated IDO inhibition in CRC. Furthermore, 1-L-MT also alleviated CRC in Rag1-/- mice, demonstrating the modulatory effects of IDO independent of its role in modulating adaptive immunity. Taken together, our findings validated that the anti-proliferation effect of 1-L-MT in vitro and the prevention of CRC in vivo were through IDO-induced cell cycle disaster of colon cancer cells. Our results identified 1-L-MT as a promising candidate for the chemoprevention of CRC.