METTL3/IGF2BP3 axis inhibits tumor immune surveillance by upregulating N6-methyladenosine modification of PD-L1 mRNA in breast cancer.

BACKGROUND: Continual expression of PD-L1 in tumor cells is critical for tumor immune escape and host T cell exhaustion, however, knowledge on its clinical benefits through inhibition is limited in breast cancer. N6-methyladenosine (m6A) plays a crucial role in multiple biological activities. Our study aimed to investigate the regulatory role of the m6A modification in PD-L1 expression and immune surveillance in breast cancer. METHODS: MeRIP-seq and epitranscriptomic microarray identified that PD-L1 is the downstream target of METTL3. MeRIP-qPCR, absolute quantification of m6A modification assay, and RIP-qPCR were used to examine the molecular mechanism underlying METTL3/m6A/IGF2BP3 signaling axis in PD-L1 expression. B-NDG and BALB/c mice were used to construct xenograft tumor models to verify the phenotypes upon METTL3 and IGF2BP3 silencing. In addition, breast cancer tissue microarray was used to analyze the correlation between PD-L1 and METTL3 or IGF2BP3 expression. RESULTS: We identified that PD-L1 was a downstream target of METTL3-mediated m6A modification in breast cancer cells. METTL3 knockdown significantly abolished m6A modification and reduced stabilization of PD-L1 mRNA. Additionally, METTL3-mediated PD-L1 mRNA activation was m6A-IGF2BP3-dependent. Moreover, inhibition of METTL3 or IGF2BP3 enhanced anti-tumor immunity through PD-L1-mediated T cell activation, exhaustion, and infiltration both in vitro and in vivo. PD-L1 expression was also positively correlated with METTL3 and IGF2BP3 expression in breast cancer tissues. CONCLUSION: Our study suggested that METTL3 could post-transcriptionally upregulate PD-L1 expression in an m6A-IGF2BP3-dependent manner to further promote stabilization of PD-L1 mRNA, which may have important implications for new and efficient therapeutic strategies in the tumor immunotherapy.

Antibacterial Fusion Protein BPI21/LL-37 Modification Enhances the Therapeutic Efficacy of hUC-MSCs in Sepsis.

Sepsis, which is characterized by multiple organ dysfunctions as a result of an unbalanced host-inflammatory response to pathogens, is potentially a life-threatening condition and a major cause of death in the intensive care units (ICUs). However, effective treatment or intervention to prevent sepsis-associated lethality is still lacking. Human umbilical cord mesenchymal stem cell (hUC-MSC) transplantation has been shown to have potent immunomodulatory properties and improve tissue repair yet lacks direct antibacterial and endotoxin clearance activities. In this study, we engineered hUC-MSCs to express a broad-spectrum antibacterial fusion peptide containing BPI21 and LL-37 (named BPI21/LL-37) and confirmed that the BPI21/LL-37 modification did not affect the stemness and immunoregulatory capacities of hUC-MSCs but remarkably, enhanced its antibacterial and toxin-neutralizing activities in vitro. Furthermore, we showed that administration of BPI21/LL-37-engineered hUC-MSCs significantly reduces serum levels of tumor necrosis factor α (TNF-α), interleukin 1ß (IL-1ß), and IL-6, whereas increases that of IL-10 in cecal ligation and puncture (CLP)-induced sepsis mouse model. Administration of BPI21/LL-37-engineered hUC-MSCs significantly reduced systemic endotoxin (lipopolysaccharide [LPS]) levels and organ bacterial load, ameliorated damage to multiple organs, and improved survival. Taken together, our study demonstrates that BPI21/LL-37-engineered hUC-MSCs might offer a novel therapeutic strategy to prevent or treat sepsis via enhanced antimicrobial and anti-inflammatory properties to preserve organ functions better.

Combination of human umbilical cord mesenchymal stem (stromal) cell transplantation with IFN-γ treatment synergistically improves the clinical outcomes of patients with rheumatoid arthritis.

OBJECTIVES: To clarify the key role of circulating interferon-γ (IFN-γ) and to improve the clinical efficacy of mesenchymal stem cell (MSC) transplantation (MSCT) in patients with rheumatoid arthritis (RA). METHODS: Study of wild-type or IFN-γR-/- MSCT was first evaluated in a murine model of collagen-induced arthritis (CIA) following which a phase 1/2 randomised controlled study was conducted in 63 patients with RA who responded poorly to regular clinical treatments. Subjects were randomly assigned to an MSCT monotherapy group (n=32) or an MSCT plus recombinant human IFN-γ treatment group (n=31), with 1 year of follow-up. The primary end points consisted of efficacy as assessed as good or moderate EULAR response rates and the proportion of patients at 3 months attaining American College of Rheumatology 20 (ACR20) response rates. RESULTS: In the murine studies, wild-type MSCT significantly improved the clinical severity of CIA, while IFN-γR-/- MSCT aggravated synovitis, and joint and cartilage damage. Transitioning from the murine to the clinical study, the 3-month follow-up results showed that the efficacy and ACR20 response rates were attained in 53.3% patients with MSCT monotherapy and in 93.3% patients with MSCT combined with IFN-γ treatment (p<0.05). No new or unexpected safety issues were encountered in 1-year follow-up for either treatment group. CONCLUSIONS: The results of this study show that IFN-γ is a key factor in determining the efficacy of MSCT in the treatment of RA, and that an MSC plus IFN-γ combination therapeutic strategy can greatly improve the clinical efficacy of MSC-based therapy in RA patients.

Complement C5a induces mesenchymal stem cell apoptosis during the progression of chronic diabetic complications.

AIMS/HYPOTHESIS: Regeneration and repair mediated by mesenchymal stem cells (MSCs) are key self-protection mechanisms against diabetic complications, a reflection of diabetes-related cell/tissue damage and dysfunction. MSC abnormalities have been reported during the progression of diabetic complications, but little is known about whether a deficiency in these cells plays a role in the pathogenesis of this disease. In addition to MSC resident sites, peripheral circulation is a major source of MSCs that participate in the regeneration and repair of damaged tissue. Therefore, we investigated whether there is a deficiency of circulating MSC-like cells in people with diabetes and explored the underlying mechanisms. METHODS: The abundance of MSC-like cells in peripheral blood was evaluated by FACS. Selected diabetic and non-diabetic serum (DS and NDS, respectively) samples were used to mimic diabetic and non-diabetic microenvironments, respectively. The proliferation and survival of MSCs under different serum conditions were analysed using several detection methods. The survival of MSCs in diabetic microenvironments was also investigated in vivo using leptin receptor mutant (Lepr db/db ) mice. RESULTS: Our data showed a significant decrease in the abundance of circulating MSC-like cells, which was correlated with complications in individuals with type 2 diabetes. DS strongly impaired the proliferation and survival of culture-expanded MSCs through the complement system but not through exposure to high glucose levels. DS-induced MSC apoptosis was mediated, at least in part, by the complement C5a-dependent upregulation of Fas-associated protein with death domain (FADD) and the Bcl-2-associated X protein (BAX)/B cell lymphoma 2 (Bcl-2) ratio, which was significantly inhibited by neutralising C5a or by the pharmacological or genetic inhibition of the C5a receptor (C5aR) on MSCs. Moreover, blockade of the C5a/C5aR pathway significantly inhibited the apoptosis of transplanted MSCs in Lepr db/db recipient mice. CONCLUSIONS/INTERPRETATION: C5a-dependent apoptotic death is probably involved in MSC deficiency and in the progression of complications in individuals with type 2 diabetes. Therefore, anticomplement therapy may be a novel intervention for diabetic complications.

Opposing Roles of Wnt Inhibitors IGFBP-4 and Dkk1 in Cardiac Ischemia by Differential Targeting of LRP5/6 and ß-catenin.

BACKGROUND: Myocardial infarction is one of the leading causes of morbidity and mortality worldwide, triggering irreversible myocardial cell damage and heart failure. The role of low-density lipoprotein receptor-related proteins 5 and 6 (LRP5/6) as coreceptors of the Wnt/ß-catenin pathway in the adult heart remain unknown. Insulin-like growth factor binding protein 4 and dickkopf-related protein 1 (Dkk1) are 2 secreted LRP5/6 binding proteins that play a crucial role in heart development through preventing Wnt/ß-catenin pathway activation. However, their roles in the adult heart remain unexplored. METHODS: To understand the role of LRP5/6 and ß-catenin in the adult heart, we constructed conditional cardiomyocyte-specific LRP5/6 and ß-catenin knockout mice and induced surgical myocardial infarction. We also directly injected recombinant proteins of insulin-like growth factor binding protein 4 and Dkk1 into the heart immediately following myocardial infarction to further examine the mechanisms through which these proteins regulate LRP5/6 and ß-catenin. RESULTS: Deletion of LRP5/6 promoted cardiac ischemic insults. Conversely, deficiency of ß-catenin, a downstream target of LRP5/6, was beneficial in ischemic injury. It is interesting to note that although both insulin-like growth factor binding protein 4 and Dkk1 are secreted Wnt/ß-catenin pathway inhibitors, insulin-like growth factor binding protein 4 protected the ischemic heart by inhibiting ß-catenin, whereas Dkk1 enhanced the injury response mainly through inducing LRP5/6 endocytosis and degradation. CONCLUSIONS: Our findings reveal previously unidentified dual roles of LRP5/6 involved in the cardiomyocyte response to ischemic injury. These findings suggest new therapeutic strategies in ischemic heart disease by fine-tuning LRP5/6 and ß-catenin signaling within the Wnt/ß-catenin pathway.

B2M is a Biomarker Associated With Immune Infiltration In High Altitude Pulmonary Edema.

BACKGROUND: High altitude pulmonary edema (HAPE) is a serious mountain sickness with certain mortality. Its early diagnosis is very important. However, the mechanism of its onset and progression is still controversial. AIM: This study aimed to analyze the HAPE occurrence and development mechanism and search for prospective biomarkers in peripheral blood. METHODS: The difference genes (DEGs) of the Control group and the HAPE group were enriched by gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, and then GSEA analysis was performed. After identifying the immune-related hub genes, QPCR was used to verify and analyze the hub gene function and diagnostic value with single-gene GSEA and ROC curves, and the drugs that acted on the hub gene was found in the CTD database. Immune infiltration and its association with the hub genes were analyzed using CIBERSORT. Finally, WGCNA was employed to investigate immune invasion cells' significantly related gene modules, following enrichment analysis of their GO and KEGG. RESULTS: The dataset enrichment analysis, immune invasion analysis and WGCNA analysis showed that the occurrence and early progression of HAPE were unrelated to inflammation. The hub genes associated with immunity obtained with MCODE algorithm of Cytoscape were JAK2 and B2M.. RT-qPCR and ROC curves confirmed that the hub gene B2M was a specific biomarker of HAPE and had diagnostic value, and single-gene GSEA analysis confirmed that it participated in MHC I molecule-mediated antigen presentation ability decreased, resulting in reduced immunity. CONCLUSION: Occurrence and early progression of high altitude pulmonary edema may not be related to inflammation. B2M may be a new clinical potential biomarker for HAPE for early diagnosis and therapeutic evaluation as well as therapeutic targets, and its decrease may be related to reduced immunity due to reduced ability of MCH I to participate in antigen submission.

The GRHL3-regulated long non-coding RNA lnc-DC modulates keratinocytes differentiation by interacting with IGF2BP2 and up-regulating ZNF750.

BACKGROUND: Aberrant keratinocytes differentiation has been demonstrated to be associated with a number of skin diseases. The roles of lncRNAs in keratinocytes differentiation remain to be largely unknown. OBJECTIVE: Here we aim to investigate the role of lnc-DC in regulating epidermal keratinocytes differentiation. METHODS: Expression of lnc-DC in the skin was queried in AnnoLnc and verified by FISH. The lncRNA expression profiles during keratinocytes differentiation were reanalyzed and verified by qPCR and FISH. Gene knock-down and over-expression were used to explore the role of lnc-DC in keratinocytes differentiation. The downstream target of lnc-DC was screened by whole transcriptome sequencing. CUT&RUN assay and siRNAs transfection was used to reveal the regulatory effect of GRHL3 on lnc-DC. The mechanism of lnc-DC regulating ZNF750 was revealed by RIP assay and RNA stability assay. RESULTS: Lnc-DC was biasedly expressed in skin and up-regulated during epidermal keratinocytes differentiation. Knockdown lnc-DC repressed epidermal keratinocytes differentiation while over-express lnc-DC showed the opposite effect. GRHL3, a well-known transcription factor regulating keratinocytes differentiation, could bind to the promoter of lnc-DC and regulate its expression. By whole transcriptome sequencing, we identified that ZNF750 was a downstream target of lnc-DC during keratinocytes differentiation. Mechanistically, lnc-DC interacted with RNA binding protein IGF2BP2 to stabilize ZNF750 mRNA and up- regulated its downstream targets TINCR and KLF4. CONCLUSION: Our study revealed the novel role of GRHL3/lnc-DC/ZNF750 axis in regulating epidermal keratinocytes differentiation, which may provide new therapeutic targets of aberrant keratinocytes differentiation related skin diseases.

WTAP/YTHDF1-mediated m6A modification amplifies IFN-γ-induced immunosuppressive properties of human MSCs.

INTRODUCTION: The immunosuppressive capacity of mesenchymal stem cells (MSCs) is dependent on the "license" of several pro-inflammatory factors to express immunosuppressive molecular profiles, which determines the therapeutic efficacy of MSCs in immune-mediated inflammatory diseases. Of those, interferon-γ (IFN-γ) is a key inducer for the expression of immunosuppressive molecular profiles; however, the mechanism underlying this effect is unknown. OBJECTIVES: To elucidate the regulation mechanism and biological functions of N6-methyladenosine (m6A) modification in the immunosuppressive functions by the IFN-γ-licensing MSCs. METHODS: Epitranscriptomic microarray analysis and MeRIP-qPCR assay were performed to identify the regulatory effect of WTAP in the IFN-γ-licensing MSCs. RIP-qPCR, western blot, qRT-PCR and RNA stability assays were used to determine the regulation of WTAP/m6A/YTHDF1 signaling axis in the expression of immunosuppressive molecules. Further, functional capacity of T cells was tested using flow cytometry, and both DSS-induced colitis mice and CIA mice were constructed to clarify the effect of WTAP and YTHDF1 in MSC-mediated immunosuppression. RESULTS: We identified that IFN-γ increased the m6A methylation levels of immunosuppressive molecules, while WTAP deficiency abolished the IFN-γ-induced promotion of m6A modification. IFN-γ activated ERK signaling, which induced WTAP phosphorylation. Additionally, the stabilization of WTAP post-transcriptionally increased the mRNA expression of immunosuppressive molecules (IDO1, PD-L1, ICAM1, and VCAM1) in an m6A-YTHDF1-dependent manner; this effect further impacted the immunosuppressive capacity of IFN-γ licensing MSCs on activated T cells. Notably, WTAP/YTHDF1 overexpression enhanced the therapeutic efficacy of IFN-γ licensing MSCs and restructures the ecology of inflammation in both colitis and arthritis models. CONCLUSION: Our results showed that m6A modification of IDO1, PD-L1, ICAM1, and VCAM1 mRNA mediated by WTAP-YTHDF1 is involved in the regulation of IFN-γ licensing MSCs immunosuppressive abilities, and shed a light to enhance the clinical therapeutic potential of IFN-γ-licensing MSCs.

Lavender essential oil accelerates lipopolysaccharide-induced chronic wound healing by inhibiting caspase-11-mediated macrophage pyroptosis.

Chronic wounds seriously affect the quality of life of the elderly, obese people, and diabetic patients. The excessive inflammatory response is a key driver of delayed chronic wound healing. Although lavender essential oil (EO [lav]) has been proven to have anti-inflammatory and accelerate wound curative effects, the specific molecular mechanism involved is still ambiguous. The results showed that the wounds treated with lipopolysaccharide (LPS) not only had delayed healing, but also the expression levels of pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1ß (IL-1ß), and the inflammatory mediator protein, high-mobility group box 1 protein (HMGB-1), in the wound tissues were significantly increased. However, treatment of LPS-induced chronic wounds with EO (lav) accelerated wound healing and decreased IL-1ß and HMGB-1 expression levels. It was further found that LPS induced macrophage pyroptosis to produce IL-1ß. After treatment with EO (lav), the expression level of macrophage pyroptosis marker Gasdermin D (GSDMD) and pyroptosis-related cytotoxic effects were significantly reduced. Immunofluorescence results also directly indicate that EO (lav) can protect macrophages from LPS-induced pyroptosis. Moreover, EO (lav) can down-regulate expression levels of IL-1ß, GSDMD, and nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) in the caspase-11-related pyroptotic signaling pathway. This study demonstrates that EO (lav) can reduce proinflammatory factor production and ameliorate inflammatory response by inhibiting macrophage pyroptosis, which accelerates LPS-induced chronic wound healing.

Interferon-gamma and tumor necrosis factor-alpha synergistically enhance the immunosuppressive capacity of human umbilical-cord-derived mesenchymal stem cells by increasing PD-L1 expression.

BACKGROUND: The immunosuppressive capacity of mesenchymal stem cells (MSCs) is dependent on the "license" of several proinflammatory factors to express immunosuppressive factors such as programmed cell death 1 ligand 1 (PD-L1), which determines the clinical therapeutic efficacy of MSCs for inflammatory or immune diseases. In MSCs, interferon-gamma (IFN-γ) is a key inducer of PD-L1 expression, which is synergistically enhanced by tumor necrosis factor-alpha (TNF-α); however, the underlying mechanism is unclear. AIM: To reveal the mechanism of pretreated MSCs express high PD-L1 and explore the application of pretreated MSCs in ulcerative colitis. METHODS: We assessed PD-L1 expression in human umbilical-cord-derived MSCs (hUC-MSCs) induced by IFN-γ and TNF-α, alone or in combination. Additionally, we performed signal pathway inhibitor experiments as well as RNA interference experiments to elucidate the molecular mechanism by which IFN-γ alone or in combination with TNF-α induces PD-L1 expression. Moreover, we used luciferase reporter gene experiments to verify the binding sites of the transcription factors of each signal transduction pathway to the targeted gene promoters. Finally, we evaluated the immunosuppressive capacity of hUC-MSCs treated with IFN-γ and TNF-α in both an in vitro mixed lymphocyte culture assay, and in vivo in mice with dextran sulfate sodium-induced acute colitis. RESULTS: Our results suggest that IFN-γ induction alone upregulates PD-L1 expression in hUC-MSCs while TNF-α alone does not, and that the co-induction of IFN-γ and TNF-α promotes higher expression of PD-L1. IFN-γ induces hUC-MSCs to express PD-L1, in which IFN-γ activates the JAK/STAT1 signaling pathway, up-regulates the expression of the interferon regulatory factor 1 (IRF1) transcription factor, promotes the binding of IRF1 and the PD-L1 gene promoter, and finally promotes PD-L1 mRNA. Although TNF-α alone did not induce PD-L1 expression in hUC-MSCs, the addition of TNF-α significantly enhanced IFN-γ-induced JAK/STAT1/IRF1 activation. TNF-α up-regulated IFN-γ receptor expression through activation of the nuclear factor kappa-B signaling pathway, which significantly enhanced IFN-γ signaling. Finally, co-induced hUC-MSCs have a stronger inhibitory effect on lymphocyte proliferation, and significantly ameliorate weight loss, mucosal damage, inflammatory cell infiltration, and up-regulation of inflammatory factors in colitis mice. CONCLUSION: Overall, our results suggest that IFN-γ and TNF-α enhance both the immunosuppressive ability of hUC-MSCs and their efficacy in ulcerative colitis by synergistically inducing high expression of PD-L1.

Fibroblast-like cells Promote Wound Healing via PD-L1-mediated Inflammation Resolution.

Chronic non-healing wounds fail to progress beyond the inflammatory phase, characterized by a disorder of inflammation resolution. PD-1/PD-L1, a major co-inhibitory checkpoint signaling, plays critical roles in tumor immune surveillance and the occurrence of inflammatory or autoimmune diseases, but its roles in wound healing remains unclear. Here, we described a novel function of PD-L1 in fibroblast-like cells as a positive regulator of wound healing. PD-L1 dynamically expressed on the fibroblast-like cells in the granulation tissue during wound healing to form a wound immunosuppressive microenvironment, modulate macrophages polarization from M1-type to M2-type, and initiates resolution of inflammation, finally accelerate wound healing. Loss of PD-L1 delayed wound healing, especially in mice with LPS-induced severe inflammation. Furthermore, the mainly regulatory mechanism is that combination of FGF-2 and TGF-ß1 promotes PD-L1 translation in fibroblasts through enhancing the eIF4E availability regulated by both PI3K-AKT-mTOR-4EBP1 and p38-ERK-MNK signaling pathways. Our results reveal the positive role of PD-L1 in wound healing, and provide a new strategy for the treatment of chronic wounds.

Cross talk between glucose metabolism and immunosuppression in IFN-γ-primed mesenchymal stem cells.

The immunosuppressive function "licensed" by IFN-γ is a vital attribute of mesenchymal stem cells (MSCs) widely used in the treatment of inflammatory diseases. However, the mechanism and impact of metabolic reprogramming on MSC immunomodulatory plasticity remain unclear. Here, we explored the mechanism by which glucose metabolism affects the immunomodulatory reprogramming of MSCs "licensed" by IFN-γ. Our data showed that glucose metabolism regulates the immunosuppressive function of human umbilical cord MSCs (hUC-MSCs) challenged by IFN-γ through the Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway. Furthermore, ATP facilitated the cross talk between glucose metabolism and the JAK-STAT system, which stimulates the phosphorylation of JAK2 and STATs, as well as the expression of indoleamine 2, 3-dioxygenase and programmed cell death-1 ligand. Moreover, ATP synergistically enhanced the therapeutic efficacy of IFN-γ-primed hUC-MSCs against acute pneumonia in mice. These results indicate a novel cross talk between the immunosuppressive function, glucose metabolism, and mitochondrial oxidation and provide a novel targeting strategy to enhance the therapeutic efficacies of hUC-MSCs.

TNF-α augments CXCL10/CXCR3 axis activity to induce Epithelial-Mesenchymal Transition in colon cancer cell.

Chronic inflammation-induced metastases have long been regarded as one of the significant obstacles in treating cancer. Tumor necrosis factor-α (TNF-α), a main inflammation mediator within tumor microenvironment, affects tumor development by inducing multiple chemokines to establish a complex network. Recent reports have revealed that CXCL10/CXCR3 axis affects cancer cells invasiveness and metastases, and Epithelial-mesenchymal transition (EMT) is the main reason for frequent proliferation and distant organ metastases of colon cancer (CC) cells, However, it is unclear whether TNF-α- mediated chronic inflammation can synergically enhance EMT-mediated CC metastasis through promoting chemokine expression. According to this study, TNF-α activated the PI3K/Akt and p38 MAPK parallel signal transduction pathways, then stimulate downstream NF-κB pathway p65 into the nucleus to activate CXCL10 transcription. CXCL10 enhanced the metastases of CC-cells by triggering small GTPases such as RhoA and cdc42. Furthermore, overexpression of CXCL10 significantly enhanced tumorigenicity and mobility of CC cells in vivo. We further clarified that CXCL10 activated the PI3K/Akt pathway through CXCR3, resulting in suppression of GSK-3ß phosphorylation and leading to upregulation of Snail expression, thereby regulating EMT in CC cells. These outcomes lay the foundation for finding new targets to inhibit CC metastases.

eIF4E S209 phosphorylation licenses myc- and stress-driven oncogenesis.

To better understand a role of eIF4E S209 in oncogenic translation, we generated EIF4ES209A/+ heterozygous knockin (4EKI) HCT 116 human colorectal cancer (CRC) cells. 4EKI had little impact on total eIF4E levels, cap binding or global translation, but markedly reduced HCT 116 cell growth in spheroids and mice, and CRC organoid growth. 4EKI strongly inhibited Myc and ATF4 translation, the integrated stress response (ISR)-dependent glutamine metabolic signature, AKT activation and proliferation in vivo. 4EKI inhibited polyposis in ApcMin/+ mice by suppressing Myc protein and AKT activation. Furthermore, p-eIF4E was highly elevated in CRC precursor lesions in mouse and human. p-eIF4E cooperated with mutant KRAS to promote Myc and ISR-dependent glutamine addiction in various CRC cell lines, characterized by increased cell death, transcriptomic heterogeneity and immune suppression upon deprivation. These findings demonstrate a critical role of eIF4E S209-dependent translation in Myc and stress-driven oncogenesis and as a potential therapeutic vulnerability.

Low-concentration DMSO accelerates skin wound healing by Akt/mTOR-mediated cell proliferation and migration in diabetic mice.

BACKGROUND AND PURPOSE: DMSO has been found to promote tissue repair. However, the role of DMSO in diabetic skin wound healing and the underlying molecular mechanisms are still unclear. EXPERIMENTAL APPROACH: The effects of DMSO on wound healing were evaluated by HE staining, immunohistochemistry and collagen staining using a wound model of full-thickness skin resection on the backs of non-diabetic or diabetic mice. Real-time cell analysis and 5-ethynyl-2'-deoxyuridine incorporation assays were used to study the effect of DMSO on primary fibroblast proliferation. A transwell assay was used to investigate keratinocyte migration. The associated signalling pathway was identified by western blotting and inhibitor blocking. The effect of DMSO on the translation rate of downstream target genes was studied by RT-qPCR of polyribosome mRNA. KEY RESULTS: We found that low-concentration DMSO significantly accelerated skin wound closure by promoting fibroblast proliferation in both nondiabetic and diabetic mice. In addition, increased migration of keratinocytes may also contribute to accelerated wound healing, which was stimulated by increased TGF-ß1 secretion from fibroblasts. Furthermore, we demonstrated that this effect of DMSO depends on Akt/mTOR-mediated translational control and the promotion of the translation of a set of cell proliferation-related genes. As expected, DMSO-induced wound healing and cell proliferation were impaired by rapamycin, an inhibitor of Akt/mTOR signalling. CONCLUSION AND IMPLICATIONS: DMSO can promote skin wound healing in diabetic mice by activating the Akt/mTOR pathway. Low-concentration DMSO presents an alternative medication for chronic cutaneous wounds, especially for diabetic patients.

HDAC2 inhibits EMT-mediated cancer metastasis by downregulating the long noncoding RNA H19 in colorectal cancer.

BACKGROUND: Emerging evidence suggests that epithelial mesenchymal transition (EMT) and epigenetic mechanisms promote metastasis. Histone deacetylases (HDACs) and noncoding RNAs (ncRNAs) are important epigenetic regulators. Here, we elucidated a novel role of histone deacetylase 2 (HDAC2) in regulating EMT and CRC metastasis via ncRNA. METHODS: The expression of HDACs in CRC was analyzed using the public databases and matched primary and metastatic tissues, and CRC cells with different metastatic potentials (DLD1, HCT116, SW480 and SW620). Microarray analysis was used to identify differential genes in parental and HDAC2 knockout CRC cells. EMT and histone modifications were determined using western blot and immunofluorescence. Migration ability was assessed by transwell assay, and metastasis was assessed in vivo using a tail vain injection. Gene expression and regulation was assessed by RT-PCR, chromatin immunoprecipitation and reporter assays. Protein interaction was assessed by immunoprecipitation. Specific siRNAs targeting H19, SP1 and MMP14 were used to validate their role in HDAC2 loss induced EMT and metastasis. RESULTS: Reduced HDAC2 expression was associated with poor prognosis in CRC patients and found in CRC metastasis. HDAC2 deletion or knockdown induced EMT and metastasis by upregulating the long noncoding RNA H19 (LncRNA H19). HDAC2 inhibited LncRNA H19 expression by histone H3K27 deacetylation in its promoter via binding with SP1. LncRNA H19 functioned as a miR-22-3P sponge to increase the expression of MMP14. HDAC2 loss strongly promoted CRC lung metastasis, which was suppressed LncRNA H19 knockdown. CONCLUSION: Our study supports HDAC2 as a CRC metastasis suppressor through the inhibition of EMT and the expression of H19 and MMP14.

Anti-αFR CAR-engineered NK-92 Cells Display Potent Cytotoxicity Against αFR-positive Ovarian Cancer.

Folate receptor alpha (αFR) is overexpressed in 90% of ovarian cancers, one of the most lethal gynecologic cancers. Recent studies have suggested that natural killer (NK) cells may be better chimeric antigen receptor (CAR) drivers because of their favorable innate characteristics, such as directly recognizing and killing tumor cells. However, the therapeutic effects of CAR-engineered NK cells targeting αFR in ovarian cancer have not been reported. In this research, 3 generations of anti-αFR CAR were constructed, namely αFR-ζ (first generation), αFR-28ζ (second generation), and αFR-28BBζ (third generation), and were highly expressed on the surface of NK-92 cells by lentivirus gene transfection. Three anti-αFR CAR-engineered NK-92 cells can specifically kill αFR-positive tumor cells in vitro, especially ovarian cancer cells with high αFR expression. Compared with NK-92 cells expressing αFR-ζ or αFR-28ζ, NK-92 cells expressing αFR-28BBζ showed not only higher antigen-specific cytotoxicity and proliferation but also lower antigen-induced apoptosis. Moreover, stronger degranulation and cytokine secretion were detected in NK-92 cells expressing αFR-28BBζ cocultured with αFR-positive tumor cells. Real-time cell analysis and live cell imaging recorded the process of NK-92 cells expressing αFR-28BBζ killing ovarian cancer cells in vitro. Furthermore, NK-92 cells expressing αFR-28BBζ can effectively eliminate cancer cells in a mouse xenograft model of ovarian cancer and significantly prolong the survival of tumor-bearing mice. These results demonstrate that the anti-αFR CARs redirect NK-92 cells with specific antitumor activity, and the third-generation anti-αFR CAR-engineered NK-92 cells display more potent cytotoxicity against αFR-positive ovarian cancer, laying the foundation for future clinical research.

LRP5/6 directly bind to Frizzled and prevent Frizzled-regulated tumour metastasis.

How Wnt signalling including canonical and non-canonical pathways are initiated at the cell surface is not completely understood. Here we report that Wnt receptor Frizzled (Frz) and theco-receptors LRP5 and LRP6 (LRP5/6) directly interact with each other and this interaction is regulated by the LRP6 ectodomain. Importantly, through direct binding to Frz, LRP5/6 are able to prevent Frz-regulated non-canonical pathway activation and further non-canonical pathway-mediated tumour metastasis. Knockdown of endogenous LRP5/6 promotes otherwise-nonaggressive tumour cells to migrate in vitro, whereas a soluble recombinant protein of LRP6 ectodomain suppresses migration and metastasis of otherwise-aggressive tumour cells in vitro and in vivo. Furthermore, the expression level of membrane LRP5/6 correlates inversely with metastasis in mouse and human breast cancer. Our study suggests a previously unrecognized mode of receptor interaction, revealing the mechanism of LRP5/6 in inhibition of non-canonical pathway, and a possible clinical use of the LRP6 ectodomain to impede metastasis.