Tubulointerstitial nephritis antigen-like 1 from cancer-associated fibroblasts contribute to the progression of diffuse-type gastric cancers through the interaction with integrin ß1.

BACKGROUND: Tumor cells of diffuse-type gastric cancer (DGC) are discohesive and infiltrate into the stroma as single cells or small subgroups, so the stroma significantly impacts DGC progression. Cancer-associated fibroblasts (CAFs) are major components of the tumor stroma. Here, we identified CAF-specific secreted molecules and investigated the mechanism underlying CAF-induced DGC progression. METHODS: We conducted transcriptome analysis for paired normal fibroblast (NF)-CAF isolated from DGC patient tissues and proteomics for conditioned media (CM) of fibroblasts. The effects of fibroblasts on cancer cells were examined by transwell migration and soft agar assays, western blotting, and in vivo. We confirmed the effect of blocking tubulointerstitial nephritis antigen-like 1 (TINAGL1) in CAFs using siRNA or shRNA. We evaluated the expression of TINAGL1 protein in frozen tissues of DGC and paired normal stomach and mRNA in formalin-fixed, paraffin-embedded (FFPE) tissue using RNA in-situ hybridization (RNA-ISH). RESULTS: CAFs more highly expressed TINAGL1 than NFs. The co-culture of CAFs increased migration and tumorigenesis of DGC. Moreover, CAFs enhanced the phosphorylation of focal adhesion kinase (FAK) and mesenchymal marker expression in DGC cells. In an animal study, DGC tumors co-injected with CAFs showed aggressive phenotypes, including lymph node metastasis. However, increased phosphorylation of FAK and migration were reduced by blocking TINAGL1 in CAFs. In the tissues of DGC patients, TINAGL1 was higher in cancer than paired normal tissues and detected with collagen type I alpha 1 chain (COL1A1) in the same spot. Furthermore, high TINAGL1 expression was significantly correlated with poor prognosis in several public databases and our patient cohort diagnosed with DGC. CONCLUSIONS: These results indicate that TINAGL1 secreted by CAFs induces phosphorylation of FAK in DGC cells and promotes tumor progression. Thus, targeting TINAGL1 in CAFs can be a novel therapeutic strategy for DGC.

Characterization of gastric cancer-stimulated signaling pathways and function of CTGF in cancer-associated fibroblasts.

BACKGROUND: Cancer-associated fibroblasts (CAFs) are key components of the tumor microenvironment (TME) that play an important role in cancer progression. Although the mechanism by which CAFs promote tumorigenesis has been well investigated, the underlying mechanism of CAFs activation by neighboring cancer cells remains elusive. In this study, we aim to investigate the signaling pathways involved in CAFs activation by gastric cancer cells (GC) and to provide insights into the therapeutic targeting of CAFs for overcoming GC. METHODS: Alteration of receptor tyrosine kinase (RTK) activity in CAFs was analyzed using phospho-RTK array. The expression of CAFs effector genes was determined by RT-qPCR or ELISA. The migration and invasion of GC cells co-cultured with CAFs were examined by transwell migration/invasion assay. RESULTS: We found that conditioned media (CM) from GC cells could activate multiple receptor tyrosine kinase signaling pathways, including ERK, AKT, and STAT3. Phospho-RTK array analysis showed that CM from GC cells activated PDGFR tyrosine phosphorylation, but only AKT activation was PDGFR-dependent. Furthermore, we found that connective tissue growth factor (CTGF), a member of the CCN family, was the most pronouncedly induced CAFs effector gene by GC cells. Knockdown of CTGF impaired the ability of CAFs to promote GC cell migration and invasion. Although the PDGFR-AKT pathway was pronouncedly activated in CAFs stimulated by GC cells, its pharmacological inhibition affected neither CTGF induction nor CAFs-induced GC cell migration. Unexpectedly, the knockdown of SRC and SRC-family kinase inhibitors, dasatinib and saracatinib, significantly impaired CTGF induction in activated CAFs and the migration of GC cells co-cultured with CAFs. SRC inhibitors restored the reduced expression of epithelial markers, E-cadherin and Zonula Occludens-1 (ZO-1), in GC cells co-cultured with CAFs, as well as CAFs-induced aggregate formation in a 3D tumor spheroid model. CONCLUSIONS: This study provides a characterization of the signaling pathways and effector genes involved in CAFs activation, and strategies that could effectively inhibit it in the context of GC. Video Abstract.

Targeting GAS6/AXL signaling improves the response to immunotherapy by restoring the anti-immunogenic tumor microenvironment in gastric cancer.

AIMS: Immunotherapy has shown remarkable effects on several malignancies; however, its impact on gastric cancers has been limited. Therefore, a novel strategy to overcome resistance to immunotherapy is required. In this study, we compared the gene expression profiles of two murine GC cell lines that exhibited different effects on tumor immunity. The functions of specific genes related to negative tumor immunity and the impact of a specific inhibitor were evaluated in syngeneic GC mouse models. MATERIALS AND METHODS: RT-PCR and Western blotting validated Gas6 and AXL expression in murine cell lines. RT-PCR compared YTN16 and YTN3 GC cell's impact on T cell activation. AXL, the receptor for GAS6 in YTN16, was validated by western blotting. Gas6 was inhibited in YTN16 cells using shRNA, and then the gene expression pattern, effects to T cell activation, and tumor growth were assessed. YTN16 cells were injected into mice and treated with CCB-3233, anti-PD-1 antibody, or both. Immunohistochemistry and flow cytometry evaluated tumor-infiltrating immune cells. KEY FINDINGS: YTN16 cells expressed more Gas6 and had reduced T cell activation compared to YTN3 cells. AXL activation was higher in YTN16. CCB-3233 reduced AXL phosphorylation. Knocking down Gas6 in YTN16 reduced immunosuppression-related genes and increased tumor-infiltrating T cells. Combined CCB-3233 and anti-PD-1 treatment reduced tumor growth and increased T-cell infiltration. Human GC data revealed a negative correlation between GAS6 and immune activation-related genes. SIGNIFICANCE: The GAS6/AXL pathway contributes to immunotherapy resistance in GC. Targeting this pathway may be a novel therapeutic strategy.

Molecular and Immune Profiling of Syngeneic Mouse Models Predict Response to Immune Checkpoint Inhibitors in Gastric Cancer.

PURPOSE: Appropriate preclinical mouse models are needed to evaluate the response to immunotherapeutic agents. Immunocompetent mouse models have rarely been reported for gastric cancer. Thus, we investigated immunophenotypes and responses to immune checkpoint inhibitor (ICI) in immunocompetent mouse models using various murine gastric cancer cell lines. MATERIALS AND METHODS: We constructed subcutaneous syngeneic tumors with murine gastric cancer cell lines, YTN3 and YTN16, in C57BL/6J mice. Mice were intraperitoneally treated with IgG isotype control or an anti-programmed death-ligand 1 (PD-L1) neutralizing antibody. We used immunohistochemistry to evaluate the tumor-infiltrating immune cells of formalin-fixed paraffin-embedded mouse tumor tissues. We compared the protein and RNA expression between YTN3 and YTN16 cell lines using a mouse cytokine array and RNA sequencing. RESULTS: The mouse tumors revealed distinct histological and molecular characteristics. YTN16 cells showed upregulation of genes and proteins related to immunosuppression, such as Ccl2 (CCL2) and Csf1 (M-CSF). Macrophages and exhausted T cells were more enriched in YTN16 tumors than in YTN3 tumors. Several YTN3 tumors were completely regressed by the PD-L1 inhibitor, whereas YTN16 tumors were unaffected. Although treatment with a PD-L1 inhibitor increased infiltration of T cells in both the tumors, the proportion of exhausted immune cells did not decrease in the non-responder group. CONCLUSION: We confirmed the histological and molecular features of cancer cells with various responses to ICI. Our models can be used in preclinical research on ICI resistance mechanisms to enhance clinical efficacy.

Secretome analysis reveals reduced expression of COL4A2 in hypoxic cancer-associated fibroblasts with a tumor-promoting function in gastric cancer.

BACKGROUND: Cancer-associated fibroblasts (CAFs) are major components of the tumor microenvironment (TME). Hypoxic TME is known to promote tumor progression. However, how a hypoxic condition regulates CAFs remains elusive. METHODS: To investigate the underlying mechanism involved in the regulation of gastric cancer (GC) progression by hypoxic CAFs, we performed secretome profiling. Normoxic or hypoxic CAFs conditioned media (CM) were filter-concentrated and in-gel trypsin digested. Resulting peptides were analyzed with LC-MS/MS. RESULTS: We observed that CM derived from hypoxic CAFs could promote migration of a panel of GC cell lines (AGS, SNU668, SNU638). Mass spectrometry analysis of hypoxic or normoxic CAFs CM identified 1595 proteins, of which 19 proteins (10 upregulated and 9 downregulated) were differentially expressed in the hypoxic secretome. We focused on COL4A2, whose expression was significantly decreased in hypoxic CAFs in HIF-1α-independent manner. Silencing of COL4A2 expression in normoxic CAFs phenocopied the effect of hypoxic CAFs in promoting GC cell migration. CONCLUSIONS: The reduced expression of COL4A2 in a hypoxic environment might be associated with the tumor-promoting role of hypoxic CAFs in GC.

Curcumin inhibits the cancer­associated fibroblast­derived chemoresistance of gastric cancer through the suppression of the JAK/STAT3 signaling pathway.

The present study aimed to investigate whether the Janus­activated kinase (JAK)/signal transducer and activator of transcription 3 (STAT3) signaling pathway is a critical mechanism underlying the cancer­associated fibroblast (CAF)­induced chemoresistance of gastric cancer (GC). In addition, the present study tried to suggest a natural product to compromise the effects of CAF on the chemoresistance of GC. The results of cell proliferation assay revealed that the conditioned medium (CM) collected from CAFs further increased resistance to 5­fluorouracil (5­FU) in GC cell lines. Secretome analysis revealed that the levels of several secreted proteins, including C­C motif chemokine ligand 2, C­X­C motif chemokine ligand 1, interleukin (IL)­6 and IL­8, were increased in the CM from CAFs co­cultured with cancer cells compared to CM from cancer cells. Western blot analysis revealed that CAFs activated the JAK/STAT3 signaling pathway in cancer cells. The experimental models revealed that curcumin abrogated the CAF­mediated activation of the JAK/STAT3 signaling pathway in GC cells. In vivo data revealed the synergistic effects of curcumin with 5­FU treatment in xenograft GC tumors. These data strongly suggest that the suppression of the JAK/STAT3 signaling pathway counteracts the CAF­induced chemoresistance of GC cells. It is suggested that curcumin may be a suitable natural product which may be used to overcome chemoresistance by inhibiting the CAF­induced activation of the JAK/STAT3 signaling pathway in GC.

Spatially Distinct Reprogramming of the Tumor Microenvironment Based On Tumor Invasion in Diffuse-Type Gastric Cancers.

PURPOSE: Histologic features of diffuse-type gastric cancer indicate that the tumor microenvironment (TME) may substantially impact tumor invasiveness. However, cellular components and molecular features associated with cancer invasiveness in the TME of diffuse-type gastric cancers are poorly understood. EXPERIMENTAL DESIGN: We performed single-cell RNA-sequencing (scRNA-seq) using tissue samples from superficial and deep invasive layers of cancerous and paired normal tissues freshly harvested from five patients with diffuse-type gastric cancer. The scRNA-seq results were validated by immunohistochemistry (IHC) and duplex in situ hybridization (ISH) in formalin-fixed paraffin-embedded tissues. RESULTS: Seven major cell types were identified. Fibroblasts, endothelial cells, and myeloid cells were categorized as being enriched in the deep layers. Cell type-specific clustering further revealed that the superficial-to-deep layer transition is associated with enrichment in inflammatory endothelial cells and fibroblasts with upregulated CCL2 transcripts. IHC and duplex ISH revealed the distribution of the major cell types and CCL2-expressing endothelial cells and fibroblasts, indicating tumor invasion. Elevation of CCL2 levels along the superficial-to-deep layer axis revealed the immunosuppressive immune cell subtypes that may contribute to tumor cell aggressiveness in the deep invasive layers of diffuse-type gastric cancer. The analyses of public datasets revealed the high-level coexpression of stromal cell-specific genes and that CCL2 correlated with poor survival outcomes in patients with gastric cancer. CONCLUSIONS: This study reveals the spatial reprogramming of the TME that may underlie invasive tumor potential in diffuse-type gastric cancer. This TME profiling across tumor layers suggests new targets, such as CCL2, that can modify the TME to inhibit tumor progression in diffuse-type gastric cancer.See related commentary by Huang and Brekken, p. 6284.

Cancer-Associated Fibroblast-Induced Resistance to Chemotherapy and Radiotherapy in Gastrointestinal Cancers.

In the past few decades, the role of cancer-associated fibroblasts (CAFs) in resistance to therapies for gastrointestinal (GI) cancers has emerged. Clinical studies focusing on GI cancers have revealed that the high expression of CAF-related molecules within tumors is significantly correlated with unfavorable therapeutic outcomes; however, the exact mechanisms whereby CAFs enhance resistance to chemotherapy and radiotherapy in GI cancers remain unclear. The cells of origin of CAFs in GI cancers include normal resident fibroblasts, mesenchymal stem cells, endothelial cells, pericytes, and even epithelial cells. CAFs accumulated within GI cancers produce cytokines, chemokines, and growth factors involved in resistance to therapies. CAF-derived exosomes can be engaged in stroma-related resistance to treatments, and several non-coding RNAs, such as miR-92a, miR-106b, CCAL, and H19, are present in CAF-derived exosomes and transferred to GI cancer cells. The CAF-induced desmoplastic reaction interferes with drug delivery to GI cancer cells, evoking resistance to chemotherapy. However, due to the heterogeneity of CAFs in GI cancers, identifying the exact mechanism underlying CAF-induced resistance may be difficult. Recent advancements in single-cell "omics" technologies could offer clues for revealing the specific subtypes and biomarkers related to resistance.

Inhibiting the GAS6/AXL axis suppresses tumor progression by blocking the interaction between cancer-associated fibroblasts and cancer cells in gastric carcinoma.

BACKGROUND: The effects of cancer-associated fibroblasts (CAF) on the progression of gastric carcinoma (GC) has recently been demonstrated. However, agents targeting the interaction between CAF and GC cells have not been applied in a clinical setting. Here, we examined if inhibition for Axl receptor tyrosine kinase (AXL) can suppress CAF-induced aggressive phenotype in GC. METHODS: We investigated the function of CAF-derived growth arrest-specific 6 (GAS6), a major ligand of AXL, on the migration and proliferation of GC cells. The effect of the AXL inhibitor, BGB324, on the CAF-induced aggressive phenotype of GC cells was also investigated. In addition, we performed immunohistochemistry to examine the expression of phosphorylated AXL protein in 175 GC tissues and evaluated its correlation with the prognosis. RESULTS: The qPCR and western blot analysis showed that GAS6 expression was higher in CAF relative to other cells. We found that co-culture with CAF increased the phosphorylation of AXL (P-AXL), differentiation into a mesenchymal-like phenotype, and cell survival in GC cell lines. When the expression of AXL was genetically inhibited in GC cells, the effect of CAF was reduced. BGB324, a small molecule inhibitor of AXL, suppressed the effects of CAF on GC cell lines. In GC tissues, high levels of P-AXL were significantly associated with poor overall survival (P = 0.022). CONCLUSIONS: We concluded that CAF are a major source of GAS6 and that GAS6 promotes an aggressiveness through AXL activation in GC. We suggested that an AXL inhibitor may be a novel agent for GC treatment.

Vasorelaxant Effect of Prunus mume (Siebold) Siebold & Zucc. Branch through the Endothelium-Dependent Pathway.

Korean plum (Prunus mume (Siebold) Siebold & Zucc.) has long been used as a health food or herbal medicine in Asia. Previous studies have shown that several plants of the genus Prunus have vasodilatory and antihypertensive effects; we hypothesized that P. mume branches may have a vasorelaxant effect. In this study, we evaluated the effects and action mechanism of 70% ethanol extract of P. mume branch (PMB) on isolated rat aortic rings. Inhibitors such as NG-nitro-l-arginine methyl ester, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, methylene blue, indomethacin, atropine, tetraethylammonium chloride, glibenclamide, 4-aminopyridine and BaCl2 were used to investigate the mechanism of vasodilation responsible for the vascular relaxation. PMB (2-30 µg/mL) induced vasorelaxation in the presence of vascular endothelium, and all inhibitors used in this study affected the degree of relaxation. These results suggest that the vasorelaxant effect of PMB is endothelium-dependent and affects the nitric oxide-cyclic guanosine monophosphate pathway, prostacyclin pathway, muscarinic receptor pathway, and potassium channels. Our study explains that PMB may be another approach to hypertension treatment to reduce the burden of cardiovascular disease.

Endothelium-Dependent Vasorelaxant Effect of Prunus Persica Branch on Isolated Rat Thoracic Aorta.

Peach (Prunus persica (L.) Batsch) is a popular fruit consumed by people worldwide, owing to its pleasant flavor and high mineral nutrient content. A few plants from the genus Prunus, such as Prunus yedoensis, Prunus cerasus, and Prunus serotina have shown vasorelaxant and vasodilatory effects, to date, no study has investigated the vasorelaxation effects of the P. persica branch extract (PPE). The vasorelaxant effect of PPE was endothelium-dependent, and it was related to the NO-sGC-cGMP, vascular prostacyclin, and muscarinic receptor transduction pathway. K+ channels, such as the BKCa, KV, and KATP channels, were partially associated with PPE-induced vasorelaxation. PPE was effective in relaxing serotonin (5-HT)- or angiotensin II-induced contraction; furthermore, PPE attenuated Ca2+-induced vasoconstriction by IP3 receptors in the SR membrane, but its vasorelaxant effect was not associated with the influx of extracellular Ca2+ via receptor-operative Ca2+ channels or voltage-dependent Ca2+ channels. Recognizing the rising use of functional foods for hypertension treatment, our findings imply that PPE may be a natural antihypertensive agent.

Role of Cancer-Associated Fibroblast in Gastric Cancer Progression and Resistance to Treatments.

Although the survival of gastric cancer (GC) patients has gradually improved, the outcomes of advanced GC patients remain unsatisfactory despite standard treatment with conventional chemotherapy or targeted agents. Several studies have shown that cancer-associated fibroblasts (CAFs), a major component of tumor stroma in GC, may have significant roles in GC progression and resistance to treatments. CAFs are a major source of various secreted molecules in the tumor microenvironment, which stimulate cancer cells and other noncancerous components of GC. Surprisingly, these factors could be involved in gastric carcinogenesis. Cytokines, including interleukin-6 and interleukin-11, or growth factors, such as fibroblast growth factor produced from CAFs, can directly activate GC cells and consequently lead to the development of an aggressive phenotype. Galectin-1 or hepatocyte growth factor can be involved in CAF-derived neovascularization in GC. In addition, recent studies showed that CAFs can affect tumor immunity through M2 polarization of tumor-associated macrophages. Finally, the current study aimed to introduce several inhibitory agents and evaluate their suppressive effects on CAFs in patients with GC progression. However, further studies are required to evaluate their safety and select appropriate patients for application in clinical settings.

Targeting interleukin-6 as a strategy to overcome stroma-induced resistance to chemotherapy in gastric cancer.

BACKGROUND: Although the tumor stroma in solid tumors like gastric cancer (GC) plays a crucial role in chemo-resistance, specific targets to inhibit the interaction between the stromal and cancer cells have not yet been utilized in clinical practice. The present study aims to determine whether cancer-associated fibroblasts (CAFs), a major component of the tumor stroma, confer chemotherapeutic resistance to GC cells, and to discover potential targets to improve chemo-response in GC. METHODS: To identify CAF-specific proteins and signal transduction pathways affecting chemo-resistance in GC cells, secretome and transcriptome analyses were performed. We evaluated the inhibiting effect of CAF-specific protein in in vivo and in vitro models and investigated the expression of CAF-specific protein in human GC tissues. RESULTS: Secretome and transcriptome data revealed that interleukin-6 (IL-6) is a CAF-specific secretory protein that protects GC cells via paracrine signaling. Furthermore, CAF-induced activation of the Janus kinase 1-signal transducer and activator of transcription 3 signal transduction pathway confers chemo-resistance in GC cells. CAF-mediated inhibition of chemotherapy-induced apoptosis was abrogated by the anti-IL-6 receptor monoclonal antibody tocilizumab in various experimental models. Clinical data revealed that IL-6 was prominently expressed in the stromal portion of GC tissues, and IL-6 upregulation in GC tissues was correlated with poor responsiveness to chemotherapy. CONCLUSIONS: Our data provide plausible evidence for crosstalk between GC cells and CAFs, wherein IL-6 is a key contributor to chemoresistance. These findings suggest the potential therapeutic application of IL-6 inhibitors to enhance the responsiveness to chemotherapy in GC.

Scaffold-Assisted Ectopic Transplantation of Internal Organs and Patient-Derived Tumors.

Xenotransplantation of human tissues into immunodeficient mice has emerged as an invaluable preclinical model to study human biology and disease progression and predict clinical response. The most common anatomical site for tissue transplantation is the subcutaneous pocket due to simple surgical procedures and accessibility for gross monitoring and advanced imaging modalities. However, subcutaneously implanted tissues initially experience a sharp change in oxygen and nutrient supply and increased mechanical deformation. During this acute phase of tissue integration to the host vasculature, substantial cell death and tissue fibrosis occur limiting engraftment efficiency. Previously, we demonstrated that the implantation of inverted colloidal crystal hydrogel scaffolds triggers proangiogenic and immunomodulatory functions without characteristic foreign body encapsulation. In this study, we examine the use of this unique host response to improve the ectopic transplantation of tissues to the subcutaneous site. Scaffold-assisted tissues preserved morphological features and blood vessel density compared to native tissues, whereas scaffold-free tissues collapsed and were less vascularized. Notably, the supporting biomaterial scaffold modulated the foreign body response to reduce the localization of Ly6G+ cells within the transplanted tissues. Cotransplantation of patient-derived gastric cancer with a scaffold resulted in a comparable level of engraftment to conventional methods; however, detailed immunohistological characterization revealed significantly better retention of proliferative cells (Ki67+) and human immune cells (CD45+) by the end of the study. We envision that leveraging the immunomodulatory properties of biomaterial interfaces can be an attractive strategy to improve the functional engraftment of xenotransplants and accelerate individualized diagnostics and the development of novel therapeutic strategies.

Inhibition of Discoidin Domain Receptor 1 Prevents Stroma-Induced Peritoneal Metastasis in Gastric Carcinoma.

Discoidin domain receptor 1 (DDR1) is activated by fibrillar (triple-helical) collagens and collagen IV, which are major components of tumor stroma; thus, DDR1 might be a critical mediator of communication between cancer cells and stroma. The aim of this study was to investigate the effect of DDR1 inhibition on stroma-induced peritoneal metastasis in gastric carcinoma. We analyzed by immunohistochemistry the correlation between DDR1 expression and the pattern of recurrence in gastric carcinoma tissues from a previously characterized and established gastric carcinoma patient cohort. We also cocultured human gastric carcinoma cell lines with gastric cancer-associated fibroblasts (CAF) and investigated DDR1 expression and activation. We evaluated CAF-induced tumorigenic properties of gastric carcinoma cell lines and the effect of a DDR1-specific inhibitor in organotypic cultures and in a peritoneal seeding xenograft animal model. The expression of DDR1 in gastric cancer tissues was positively associated with early recurrence (P = 0.043) and a high incidence of peritoneal recurrence (P = 0.036). We confirmed that coculturing with CAFs elevated DDR1 protein expression in gastric carcinoma cell lines and enhanced gastric carcinoma cell line spheroid formation in organotypic cultures in a tumor cell DDR1-dependent manner. Coimplantation of CAFs with gastric carcinoma cells enhanced peritoneal tumor formation in vivo, an effect that was sensitive to pharmacologic inhibition of DDR1.Implications: This study highlights that CAF-induced elevation of DDR1 expression in gastric carcinoma cells enhances peritoneal tumorigenesis, and that inhibition of DDR1 is an attractive strategy for the treatment of gastric carcinoma peritoneal metastasis. Mol Cancer Res; 16(10); 1590-600. ©2018 AACR.

Gastrokine 1 protein is a potential theragnostic target for gastric cancer.

BACKGROUND: Gastrokine 1 (GKN1) plays important roles in maintaining mucosal homeostasis, and in regulating cell proliferation and differentiation. Here, we determined whether GKN1 is a potential theragnostic marker for gastric cancer. METHODS: We identified GKN1 binding proteins using the protein microarray assay and investigated whether GKN1 is one of the exosomal cargo proteins by western blot, immunoprecipitation, and immunofluorescent assays. Cell proliferation and apoptosis were analyzed by MTT, BrdU incorporation, flow cytometry, and western blot assays. We further validated the functional relevance of exosomal GKN1 in MKN1-injected xenograft mice. The possibility of serum GKN1 as a diagnostic marker for gastric cancer was determined by ELISA assay. RESULTS: In protein microarray assay, GKN1 binding to 27 exosomal proteins was clearly observed. GKN1 was expressed in exosomes derived from HFE-145 gastric epithelial cells by western blot and immunofluorescent assays, but not in exosomes from AGS and MKN1 gastric cancer cells. Exosomes carrying GKN1 inhibited cell proliferation and induced apoptosis in both AGS and MKN1 cells, and exosomes carrying GKN1-treated nude mice-bearing MKN1 xenograft tumors exhibited significantly reduced tumor volume and tumor weight. Silencing of clathrin markedly down-regulated the internalization of exosomal GKN1. Interestingly, serum GKN1 concentrations in patients with gastric cancer were significantly lower than those in healthy individuals and patients with colorectal and hepatocellular carcinomas. CONCLUSIONS: The GKN1 is secreted and internalized in the gastric epithelium by exosome-driven transfer, which inhibits gastric tumorigenesis and supports the clinical application of GKN1 protein in gastric cancer diagnosis and treatment.

Experimental research of hypotensive and hypolipidemic effects with Modified Sanhuang Xiexin Decoction ().

OBJECTIVE: To investigate the hypotensive and hypolipidemic effects of Modified Sanhuang Xiexin Decoction (, HVC1), a herbal prescription for the vascular diseases in Chinese medicine and evaluate the acute and subchronic oral toxicities. METHODS: Fifty-six spontaneous hypertensive rats (SHRs) were used to investigate the hypotensive and hypolipidemic effect of HVC1. Rats in the normal group (n=8) were fed with normal diet. The rats in the other groups (n=48) were fed with high fat and cholesterol diet for inducing hyperlipidemia models. Forty-eight rats were randomly divided into 6 groups [model, positive control (amlodipine, simvastain), 50, 250, and 1,000 mg/(kg•d) HVC1 groups] with 8 animals in each group. Normal and model groups were treated with distilled water [1 mL/(kg•d)], the positive control group was treated with amlodipine [5 mg/(kg•d)] or simvastatin [10 mg/(kg•d)], and the HVC1 groups were treated with HVC1 [50, 250, or 1,000 mg/(kg•d)] for 8 weeks, respectively. Blood pressure (BP) of the rats was measured using a non-invasive tail cuff system. On the last day of the experiment, serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglyceride (TG) levels were measured. To investigate the safety of HVC1, acute and subchronic toxicity studies were conducted on Sprague-Dawley rats. In toxicity studies, the body weight, food and water consumption of rats were measured and clinical signs observation, ophthalmologic examinations, urinalysis, hematological analysis, and serum biochemical analysis were performed. RESULTS: A dose of 50 and 250 mg/(kg•d) HVC1 lowered systolic and diastolic BP (P<0.05). HVC1 at 1,000 mg/(kg•d) decreased TC, LDL-C and TG levels, respectively (P<0.01 or P<0.05) and 250 mg/(kg•d) HVC1 decreased TG levels on hyperlipidemic SHRs (P<0.05). In the acute toxicity study, oral administration of HVC1 did not show any toxicity effect, and the median lethal dose value of HVC1 was greater than 5,000 mg/kg. In the subchronic toxicity study, oral administration of HVC1 for 4 weeks also did not show any toxicity effect, and the no-observedadverse-effect-level of HVC1 was established as 2,000 mg/(kg•d). CONCLUSION: These results could be used as preclinical data for clinical trials that develop HVC1 as a herbal medicine for treating or preventing hypertension and hyperlipidemia.

Vasorelaxant effects of Angelica decursiva root on isolated rat aortic rings.

BACKGROUND: Hypertension is one of the most important risk factors for cardiovascular disease (CVD) and a worldwide problem. Despite increases in the development of synthetic drugs for hypertension treatment, the rate of untreated and uncontrolled hypertension remains high. These drugs are effective, but can also cause side effects. Approximately 80% of the world population uses herbal medicines because of their low toxicity and better acceptability by the human body. Therefore, we attempted to identify natural medications for treating hypertension. The 70% ethanol extract of Angelica decursiva root (ADE) shows strong vasorelaxant potential, but no studies have investigated the mechanisms underlying the vasorelaxation effect of A. decursiva. METHODS: Dried root of A. decursiva was identified by DNA sequencing and was extracted once with 1 L 70% ethanol (EtOH) for 3 h in a reflux apparatus at 70 °C. ADE was evaluated for its vasorelaxant effects in rat thoracic aortas. Various inhibitors of ADE-induced vasorelaxation were used. RESULTS: ADE showed vasorelaxant effects on the intact and denuded endothelium of aortic rings pre-contracted with phenylephrine and KCl in Krebs-Henseleit solution. Tetraethylammonium and 4-aminopyridine did not alter ADE-induced vasorelaxation. However, the vasorelaxant effect of ADE was partially inhibited by pre-treatment with glibenclamide an ATP-sensitive K+ channel blocker. Furthermore, ADE concentration-dependently inhibited Ca2+ supplementation-induced vasoconstriction of aortic rings that had been pretreated with phenylephrine or KCl in Ca2+-free Krebs-Henseleit solution. CONCLUSIONS: These results suggest that ADE-induced vasorelaxation occurred in an endothelium-independent manner. The vasorelaxant effects of ADE were correlated with blockade of the KATP channel and inhibition of Ca2+ influx via receptor-operative Ca2+ channels or voltage-dependent Ca2+ channels.

AKT inhibition is an effective treatment strategy in ARID1A-deficient gastric cancer cells.

BACKGROUND: The At-rich interactive domain 1A (ARID1A) is frequently mutated in gastric cancers (GCs) with a poor prognosis. Growing evidence indicates that loss of ARID1A expression leads to activation of the phosphatidylinositol 3-kinase (PI3K)/AKT pathway by AKT phosphorylation. We aim to investigate the different sensitivity for the AKT inhibitor in ARID1A-deficient GC cells. METHODS: After transfection using siRNA or shRNA, the effect of ARID1A knockdown on the PI3K/AKT signaling pathway was evaluated by Western blot analysis. ARID1A-knockdown cells were treated with AKT inhibitor (GSK690693), 5-fluorouracil, or cisplatin, alone or in combination. Viability and apoptosis were analyzed using EZ-CYTOX cell viability assay and flow cytometry, respectively. RESULTS: ARID1A depletion accelerated the phosphorylation of AKT and S6 in a dose-dependent manner and led to an increased proliferation of MKN-1, MKN-28, and KATO-III GC cells (P<0.001). ARID1A-deficient cells were more vulnerable to GSK690693 in comparison to the controls (P<0.001), even at very low doses. Flow cytometry confirmed the increased apoptosis in ARID1A-deficient cells treated with GSK690693 (0.01 µmol/L; P<0.001). In contrast to our expectations, ARID1A depletion did not cause resistance to 5-fluorouracil or cisplatin. Addition of GSK690693 to the conventional chemotherapy induced more decreased cell viability in ARID1A-knockdown cells (P<0.01). CONCLUSION: Loss of ARID1A expression is a surrogate marker for the activation of the AKT signaling pathway and is also a reliable biomarker to predict the response for the AKT inhibitor. We anticipate that appropriate patient selection based on ARID1A expression in the tumor tissue will increase the drug sensitivity for the AKT inhibition and improve the clinical outcome.

Wound Healing Effects of Prunus yedoensis Matsumura Bark in Scalded Rats.

Pruni Cortex has been used to treat asthma, measles, cough, urticaria, pruritus, and dermatitis in traditional Korean medicine. The objective of this study was to investigate the effects of Prunus yedoensis Matsumura bark methanol extract (PYE) on scald-induced dorsal skin wounds in rats. Scalds were produced in Sprague-Dawley rats with 100°C water and treated with 5% and 20% PYE (using Vaseline as a base), silver sulfadiazine (SSD), and Vaseline once a day for 21 days, beginning 24 hours after scald by treatment group allocation. The PYE-treated groups showed accelerated healing from 12 days after scald, demonstrated by rapid eschar exfoliation compared to the control and SSD groups. PYE-treated groups showed higher wound contraction rates and better tissue regeneration in comparison with the control group. Serum analysis showed that transforming growth factor beta 1 and vascular endothelial growth factor levels remained high or gradually increased up to day 14 in both PYE groups and then showed a sharp decline by day 21, implying successful completion of the inflammatory phase and initiation of tissue regeneration. These findings suggested that PYE is effective in promoting scald wound healing in the inflammation and tissue proliferation stages.