BACKGROUND: The transcription factor POU2F1 regulates the expression levels of microRNAs in neoplasia. However, the miR-29b1/a cluster modulated by POU2F1 in gastric cancer (GC) remains unknown. METHODS: Gene expression in GC cells was evaluated using reverse-transcription polymerase chain reaction (PCR), western blotting, immunohistochemistry, and RNA in situ hybridization. Co-immunoprecipitation was performed to evaluate protein interactions. Transwell migration and invasion assays were performed to investigate the biological behavior of GC cells. MiR-29b1/a cluster promoter analysis and luciferase activity assay for the 3'-UTR study were performed in GC cells. In vivo tumor metastasis was evaluated in nude mice. RESULTS: POU2F1 is overexpressed in GC cell lines and binds to the miR-29b1/a cluster promoter. POU2F1 is upregulated, whereas mature miR-29b-3p and miR-29a-3p are downregulated in GC tissues. POU2F1 promotes GC metastasis by inhibiting miR-29b-3p or miR-29a-3p expression in vitro and in vivo . Furthermore, PIK3R1 and/or PIK3R3 are direct targets of miR-29b-3p and/or miR-29a-3p , and the ectopic expression of PIK3R1 or PIK3R3 reverses the suppressive effect of mature miR-29b-3p and/or miR-29a-3p on GC cell metastasis and invasion. Additionally, the interaction of PIK3R1 with PIK3R3 promotes migration and invasion, and miR-29b-3p , miR-29a-3p , PIK3R1 , and PIK3R3 regulate migration and invasion via the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway in GC cells. In addition, POU2F1 , PIK3R1 , and PIK3R3 expression levels negatively correlated with miR-29b-3p and miR-29a-3p expression levels in GC tissue samples. CONCLUSIONS The POU2F1 - miR-29b-3p / miR-29a-3p-PIK3R1 / PIK3R1 signaling axis regulates tumor progression and may be a promising therapeutic target for GC.
MicroRNAs/metabolism* ; Humans ; Stomach Neoplasms/pathology* ; Cell Line, Tumor ; Cell Movement/physiology* ; Phosphatidylinositol 3-Kinases/metabolism* ; Animals ; Mice ; Octamer Transcription Factor-1/metabolism* ; Mice, Nude ; Class Ia Phosphatidylinositol 3-Kinase/metabolism* ; Neoplasm Invasiveness ; Gene Expression Regulation, Neoplastic/genetics* ; Male ; Immunohistochemistry ; Female

This study aims to investigate the pathogenesis of precancerous lesions of gastric cancer(PLGC) and explore the potential molecular mechanism of Weifuchun Capsules(WFC) in treating PLGC via the nuclear factor-κB(NF-κB)/NOD-like receptor protein 3(NLRP3) inflammasome signaling pathway. Ninety male SPF-grade Wistar rats were randomized into a normal feeding group and a modeling group. The normal feeding group received a regular diet, while the modeling group was subjected to the disease-syndrome combined modeling of PLGC. Specifically, the rats had free access to the water containing 120 μg·mL~(-1) N-methyl-N'-nitro-N-nitrosoguanidine(MNNG) and received a diet containing 0.05% ranitidine in an irregular feeding pattern(alternations between fasting and overfeeding). After 15 weeks, the rats in the normal feeding group were randomized into control, control-NF-κB activator betulinic acid(C-BA), and control-NF-κB inhibitor pyrrolidine dithiocarbamaten(C-PDTC) groups. Meanwhile, the rats in the modeling group continuously underwent the modeling procedure and were randomized into model, WFC, model-NF-κB activator(M-BA), and model-NF-κB inhibitor(M-PDTC) groups. The model group and control group were given aseptic water by intragastric administration, once a day. WFC was given at a dose(432 mg·kg~(-1)) 6 times the equivalent dose for adults(body weight: 60 kg) by gavage, once a day. The rats in the C-BA and M-BA groups were administrated with BA by intraperitoneal injection at a dose of 10 mg·kg~(-1), twice a week. The rats in the C-PDTC and M-PDTC groups were administrated with PDTC by intraperitoneal injection at a dose of 50 mg·kg~(-1), twice a week. The interventions were carried out for 4 weeks. Histopathological changes of the gastric mucosa were observed and scored by hematoxylin-eosin(HE) and alcian blue-periodic acid Sthiff(AB-PAS) staining. The levels of inflammatory cytokines including interleukin(IL)-1β, IL-6, IL-18, tumor necrosis factor-alpha(TNF-α), and IL-10 in the gastric tissue were determined by enzyme-linked immunosorbent assay(ELISA). The expression levels of proteins associated with the NF-κB/NLRP3 inflammasome in the gastric mucosa were determined by Western blot. The positive expression areas of proteins related to NF-κB/NLRP3 inflammasome in the gastric mucosa were measured by immunohistochemistry. The results showed that compared with the control group, the model, C-BA, and M-BA groups showed significantly risen scores of mucosal inflammation, degree of inflammatory activity, gland atrophy, and intestinal metaplasia, and the model and M-BA groups showed significanly risen scores of dysplasia. Compared with the model group, the WFC group demonstrated significantly declined scores of mucosal inflammation and degree of inflammatory activity, as well as declined scores of intestinal metaplasia and dysplasia. Compared with the control group, the model and C-BA groups showed significantly elevated levels of IL-1β, IL-6, IL-18, and TNF-α in the gastric tissue, and the model group showed significantly elevated level of IL-10. In addition, the model and C-BA groups showed significantly up-regulated expression of NF-κB p65, NLRP3, cysteine-aspartic acid protease 1(caspase-1), and apoptosis-associated speck-like protein containing a CARD(ASC) in the gastric mucosa and increased positive expression areas of NF-κB p65, NLRP3, and ASC. Compared with the model group, the WFC group showed significantly decreased levels of IL-1β, IL-6, IL-18, TNF-α, and IL-10 in the gastric tissue, and the M-PDTC group showed significantly lowered levels of IL-1β, IL-18, and TNF-α in the gastric mucosa. Both WFC and M-PDTC groups demonstrated significantly down-regulated expression levels of NF-κB p65, phosphorylated NF-κB p65(p-NF-κB p65), NLRP3, and caspase-1 in the gastric mucosa, along with significant decreases in the positive expression areas of NF-κB p65, NLRP3, and ASC. In conclusion, the pathogenesis of PLGC is closely related to the activation of the NF-κB/NLRP3 inflammasome signaling pathway. WFC can alleviate mucosal inflammation, inhibit glandular atrophy, partially reverse intestinal metaplasia, and reduce dysplasia to delay the process of inflammation-cancer transformation, and meanwhile it can effectively lower the levels of inflammatory cytokines and down-regulate the expression of pathway-related proteins in the stomach. Therefore, WFC may treat PLGC by inhibiting the NF-κB/NLRP3 inflammasome signaling pathway.
Animals ; Male ; NF-kappa B/genetics* ; Rats ; Rats, Wistar ; Drugs, Chinese Herbal/administration & dosage* ; Signal Transduction/drug effects* ; NLR Family, Pyrin Domain-Containing 3 Protein/metabolism* ; Stomach Neoplasms/pathology* ; Inflammasomes/genetics* ; Humans ; Precancerous Conditions/metabolism* ; Capsules

Gastric cancer is one of the most common malignant tumors in the digestive tract, which has the characteristics of high morbidity and mortality. However, gastric cancer is not achieved overnight but is gradually developing through the interaction of many factors. Therefore, actively delaying or blocking the "inflammation-cancer" transformation in gastric mucosa is the key to treatment. Nod-like receptor protein 3(NLRP3) inflammasome is a multi-protein signal complex and one of the important innate immune signal receptors. Inflammation plays an important role in the occurrence and development of gastric cancer, and continuous inflammation mediation will trigger the transformation from inflammation to cancer. Therefore, the significance of NLRP3 inflammasome to gastric mucosa lies in the transformation between inflammation and cancer. Traditional Chinese medicine(TCM) has the functions of multi-components, multi-targets, and few adverse reactions. A large number of studies show that TCM and related monomers have significant effects in treating liver, kidney, and immune diseases through mediating NLRP3 inflammasome, but there is less research on the "inflammation-cancer" transformation in gastric mucosa. By combing the NLRP3-related nuclear factor-κB transcription factor(NF-κB), hypoxia inducible factor-1α(HIF-1α), phosphatidylinositol 3-kinase/protein kinase B(PI3K/Akt), and other signal pathways, this paper clarified their mechanisms in the "inflammation-cancer" transformation in gastric mucosa, delayed the process of "inflammation-cancer" transformation in gastric mucosa through four aspects: energy metabolism, pyroptosis, immune response, and vascular endothelial growth factor, and prevented and treated "inflammation-cancer" transformation in gastric mucosa from three aspects: TCM monomer, TCM compound prescription, and other therapies, so as to provide ideas for the subsequent treatment of "inflammation-cancer" transformation in gastric mucosa with TCM.
Humans ; NLR Family, Pyrin Domain-Containing 3 Protein/metabolism* ; Inflammasomes/metabolism* ; Gastric Mucosa/metabolism* ; Stomach Neoplasms/pathology* ; Animals ; Drugs, Chinese Herbal/pharmacology* ; Medicine, Chinese Traditional ; Inflammation/drug therapy* ; Signal Transduction/drug effects*

OBJECTIVES: To investigate the expression of CDKN3 in gastric cancer and its impact on prognosis of gastric cancer patients. METHODS: We analyzed CDKN3 expression in clinical specimens from 114 gastric cancer patients and assessed its association with 5-year postoperative survival of the patients. GO and KEGG enrichment analyses were used to predict the biological function and possible mechanism of CDKN3. The effects of lentivirus-mediated CDKN3 knockdown on biological behaviors of gastric cancer cells were evaluated using Transwell assay, CCK-8 assay, TUNEL staining, flow cytometry, and Western blotting. RESULTS: CDKN3 expression was significantly higher in gastric cancer tissues than in the adjacent tissues with significant correlations with CEA level, CA19-9 level, and T and N staging (P<0.05). High CDKN3 expression was an independent risk factor affecting 5-year postoperative survival of the patients and predictive for long-term prognosis (P<0.01). Enrichment analyses suggested a probable association of CDKN3 with apoptosis. In MGC-803 cells, CDKN3 knockdown significantly lowered migration and invasion capacities of the cells, while CDKN3 overexpression produced the opposite effects. TUNEL staining revealed a significantly lower level of cell apoptosis in gastric cancer tissues than in adjacent tissues (P<0.01). CDKN3 knockdown obviously inhibited proliferation and increased apoptosis of MGC-803 cells. CDKN3 overexpression down-regulated the expressions of p53, p21 and Bax and up-regulated the expressions of p-p65 and Bcl-2. CONCLUSIONS CDKN3 is highly expressed in gastric cancer tissues and affects patient prognosis. CDKN3 overexpression promotes proliferation, invasion and migration and suppressed apoptosis of gastric cancer cells possibly through the p53/NF-κB signaling pathway.
Humans ; Stomach Neoplasms/pathology* ; Apoptosis ; Signal Transduction ; Tumor Suppressor Protein p53/metabolism* ; Cell Movement ; Cell Line, Tumor ; NF-kappa B/metabolism* ; Prognosis ; Cyclin-Dependent Kinase Inhibitor Proteins/metabolism* ; Cell Proliferation ; Neoplasm Invasiveness ; Male ; Female ; Dual-Specificity Phosphatases

OBJECTIVES: To investigate the mechanism through which salidroside inhibits proliferation of gastric cancer (GC) cells focusing on glucose metabolic reprogramming pathways. METHODS: High-throughput sequencing combined with bioinformatics analysis was employed to identify the potential targets of salidroside in human GC MGC-803 cells. Liposome-mediated transfection experiments were carried out to validate the functional and mechanistic roles of these targets. CCK-8 and colony formation assays were used to assess the effects of salidroside on GC cell viability and clonogenic ability. qRT-PCR, Western blotting, and biochemical assay kits were used to analyze the regulatory effects of salidroside on the miR-1343-3p-OGDHL/PDHB enzyme complex-pyruvate metabolic pathway in GC cells. RESULTS: Bioinformatics analysis suggested that the tumor-suppressive factor miR-1343-3p negatively regulated the key glycolytic enzyme gene oxoglutarate dehydrogenase-like (OGDHL) in GC cells, and OGDHL and pyruvate dehydrogenase E1 subunit beta (PDHB) were both significantly upregulated in GC tissues, which was close by correlated with reduced survival rates of GC patients. In MGC-803 cells, salidroside treatment significantly enhanced the expression level of miR-1343-3p and downregulated OGDHL expression, resulting in disruption of the stability of PDHB, reduced pyruvate oxidative decarboxylation, and consequently decreased production of acetyl-CoA and ATP. CONCLUSIONS Salidroside inhibits GC cell proliferation possibly by regulating the miR-1343-3p-OGDHL/PDHB enzyme complex-pyruvate metabolic pathway, which provides new insights into its anti-tumor mechanisms and suggests new strategies for targeted therapy for GC.
Humans ; Stomach Neoplasms/pathology* ; MicroRNAs/genetics* ; Cell Proliferation/drug effects* ; Glucosides/pharmacology* ; Phenols/pharmacology* ; Cell Line, Tumor ; Glucose/metabolism* ; Pyruvate Dehydrogenase (Lipoamide)/metabolism*

OBJECTIVES: To investigate YEATS2 expression in gastric cancer (GC), its prognostic value, and its regulatory role in epithelial-mesenchymal transition (EMT) of GC cells. METHODS: YEATS2 expression in GC was analyzed using publicly available databases. Paired GC and adjacent tissues were collected from 100 patients undergoing radical surgery for immunohistochemical detection of YEATS2 expression, and its correlations with the patients' clinicopathological parameters and Ki67 expression were analyzed. The prognostic value of YEATS2 was assessed using Kaplan-Meier analysis, Cox regression and ROC curves, and its regulatory mechanisms were analyzed using KEGG enrichment analysis. In cultured GC cell lines (HGC-27 and AGS), the effect of YEATS2 knockdown and overexpression on migration, invasion and EMT of the cells were examined with scratching assay, Transwell assay and Western blotting. RESULTS: YEATS2 was significantly overexpressed in GC tissues with a positive correlation with Ki67 (P<0.05). High YEATS2 expression was associated with elevated CEA (≥5 μg/L), CA19-9 (≥37 kU/L), T3-4 stage, and N2-3 stage (all P<0.05). Patients with high YEATS2 expression had significantly reduced 5-year survival (P<0.001); ROC analysis showed that YEATS2 expression levels had a sensitivity of 80.00% and a specificity of 66.67% for predicting patient survival (P<0.05). Cox regression identified high YEATS2 as an independent risk factor for poor postoperative 5-year survival outcome of GC patients (HR: 1.675, 95%CI: 1.013-2.771; P=0.045). KEGG enrichment analysis suggested involvement of YEATS2 in EMT in GC and Wnt/β-catenin signaling. In cultured GC cells, YEATS2 overexpression significantly promoted cell migration and invasion, upregulated the expressions of vimentin, N-cadherin, Wnt and active β-catenin, and downregulated E-cadherin expression, and these changes were obviously suppressed by treatment with XAV-939 (a Wnt/β-catenin inhibitor). CONCLUSIONS High YEATS2 expression activates Wnt/β-catenin signaling to promote EMT in GC and is correlated with poor prognosis of GC patients.
Humans ; Stomach Neoplasms/pathology* ; Epithelial-Mesenchymal Transition ; Wnt Signaling Pathway ; Cell Line, Tumor ; Prognosis ; Cell Movement ; Male ; Female ; beta Catenin/metabolism*

OBJECTIVE: Gastric cancer (GC) is one of the most common malignancies seen in clinic and requires novel treatment options. Morin is a natural flavonoid extracted from the flower stalk of a highly valuable medicinal plant Prunella vulgaris L., which exhibits an anti-cancer effect in multiple types of tumors. However, the therapeutic effect and underlying mechanism of morin in treating GC remains elusive. The study aims to explore the therapeutic effect and underlying molecular mechanisms of morin in GC. METHODS: For in vitro experiments, the proliferation inhibition of morin was measured by cell counting kit-8 assay and colony formation assay in human GC cell line MKN45, human gastric adenocarcinoma cell line AGS, and human gastric epithelial cell line GES-1; for apoptosis analysis, microscopic photography, Western blotting, ubiquitination analysis, quantitative polymerase chain reaction analysis, flow cytometry, and RNA interference technology were employed. For in vivo studies, immunohistochemistry, biomedical analysis, and Western blotting were used to assess the efficacy and safety of morin in a xenograft mouse model of GC. RESULTS: Morin significantly inhibited the proliferation of GC cells MKN45 and AGS in a dose- and time-dependent manner, but did not inhibit human gastric epithelial cells GES-1. Only the caspase inhibitor Z-VAD-FMK was able to significantly reverse the inhibition of proliferation by morin in both GC cells, suggesting that apoptosis was the main type of cell death during the treatment. Morin induced intrinsic apoptosis in a dose-dependent manner in GC cells, which mainly relied on B cell leukemia/lymphoma 2 (BCL-2) associated agonist of cell death (BAD) but not phorbol-12-myristate-13-acetate-induced protein 1. The upregulation of BAD by morin was due to blocking the ubiquitination degradation of BAD, rather than the transcription regulation and the phosphorylation of BAD. Furthermore, the combination of morin and BCL-2 inhibitor navitoclax (also known as ABT-737) produced a synergistic inhibitory effect in GC cells through amplifying apoptotic signals. In addition, morin treatment significantly suppressed the growth of GC in vivo by upregulating BAD and the subsequent activation of its downstream apoptosis pathway. CONCLUSION Morin suppressed GC by inducing apoptosis, which was mainly due to blocking the ubiquitination-based degradation of the pro-apoptotic protein BAD. The combination of morin and the BCL-2 inhibitor ABT-737 synergistically amplified apoptotic signals in GC cells, which may overcome the drug resistance of the BCL-2 inhibitor. These findings indicated that morin was a potent and promising agent for GC treatment. Please cite this article as: Wang Y, Sun XY, Ma FQ, Ren MM, Zhao RH, Qin MM, Zhu XH, Xu Y, Cao ND, Chen YY, Dong TG, Pan YF, Zhao AG. Morin inhibits ubiquitination degradation of BCL-2 associated agonist of cell death and synergizes with BCL-2 inhibitor in gastric cancer cells. J Integr Med. 2025; 23(3): 320-332.
Humans ; Flavonoids/therapeutic use* ; Stomach Neoplasms/pathology* ; Animals ; Proto-Oncogene Proteins c-bcl-2/metabolism* ; Cell Line, Tumor ; Apoptosis/drug effects* ; Cell Proliferation/drug effects* ; Ubiquitination/drug effects* ; Mice ; Drug Synergism ; Mice, Inbred BALB C ; Mice, Nude ; Xenograft Model Antitumor Assays ; Flavones

Objective To investigate the expression of SORT1 in the gastric cancer tissue and analyze its relationship with clinical prognosis of patients as well as the pathways and mechanisms involved in gastric cancer progression.Methods The Gene Expression Profiling Interaction Analysis database,Western blot,and immunohistochemistry were employed to predict and analyze the expression of SORT1 in the gastric cancer and the adjacent tissue.The clinical case information of 109 patients who underwent radical surgery for gastric cancer in the First Affiliated Hospital of Bengbu Medical University from April 2015 to April 2017 was collected to analyze the relationship of SORT1 with the clinicopathological parameters and prognosis of the patients.Cell proliferation was detected by the CCK-8 assay and colony formation assay,while cell migration and invasion were assessed by the scratch assay and Transwell assay,respectively.Western blot was employed to determine the expression of proteins related to epithelial-mesenchymal transition(EMT)in gastric cancer cells,followed by further analysis on molecular mechanism through which SORT1 regulates EMT in gastric cancer cells.Results Western blot and immunocytochemistry results showed that SORT1 was highly expressed in the gastric cancer tissue(P=0.003,P<0.001),which was positively correlated with malignant progression of tumors(all P<0.05).The Kaplan-Meier survival analysis revealed shortened postoperative survival periods for the patients with high expression of SORT1(P<0.001).The Cox regression model indicated that SORT1 expression was an independent risk factor affecting the 5-year survival rate after surgery for gastric cancer patients(P<0.001).Up-regulation of SORT1 expression promoted the proliferation,migration,invasion,and EMT of gastric cancer cells(all P<0.05),while down-regulation of SORT1 showed the opposite effects(all P<0.05).Western blot results showed that high expression of SORT1 promoted the expression of β-catenin,cyclin D1,and c-Myc(all P<0.05).Moreover,in vitro use of the Wnt/β-catenin pathway inhibitor(XAV939)effectively suppressed the EMT enhancement caused by high expression of SORT1 in gastric cancer cells(all P<0.05).Conclusions SORT1 is highly expressed in gastric cancer and affects patients' postoperative survival periods.It is involved in the proliferation,migration,and invasion of gastric cancer cells and may promote the EMT of gastric cancer cells by activating the Wnt/β-catenin pathway.
Humans ; Stomach Neoplasms/pathology* ; Cell Proliferation ; Epithelial-Mesenchymal Transition ; Cell Movement ; Prognosis ; Cell Line, Tumor ; Adaptor Proteins, Vesicular Transport/metabolism* ; Male ; Female ; Middle Aged

Objective: To investigate the molecular mechanism of how lactate induces high mobility group box 1 (HMGB1) release. Methods: Gastric cancer HGC-27 cells were divided into the control group and the lactate group (The cells were treated with lactate for 6 h). The level of HMGB1 in the cell culture medium was detected by enzyme-linked immunosorbent assay (ELISA), the localization of HMGB1 was detected using laser confocal microscopy, and the nuclear translocation of HMGB1 was detected using the nucleoplasmic separation assay. The phosphorylation and acetylation levels of HMGB1 were determined by co-immunoprecipitation, and Western blot was used to measure the phosphorylation of Akt and protein kinase C (PKC). HGC-27 cells were first treated with lactate and LY294002, the inhibitor of Akt, and then the phosphorylation of HMGB1 and Akt was analyzed by co-immunoprecipitation and Western blot, respectively. The localization of HMGB1 in cells was detected by laser confocal microscopy. EdU and Transwell assays were used to detect the proliferation and migration abilities of HGC-27 cells, respectively. HGC-27 cells were then injected into the BALB/C null mice for subcutaneous tumor implantation. Mice in the lactate group were intraperitoneally injected with lactate (0.2 g/kg/2 d), while those in the control group were intraperitoneally injected with an equal amount of PBS for 20 consecutive days. ELISA was used to detect the HMGB1 levels in the blood samples taken from the medial canthus vein of the mice, while co-immunoprecipitation and Western blot were used to detect the phosphorylation of HMGB1 and Akt in tumor tissue proteins, respectively. Results: The release levels of HMGB1 in the lactate group were (2 995.00±660.91) pg/ml and (696.33±22.03) pg/ml, after lactate treatment for 6 h and 12 h, respectively, both higher than those in the control group (485.00±105.83) pg/ml (P<0.001 and P=0.028, respectively). After lactate treatment for 6 h, the relative expression of HMGB1 protein in the cytoplasm of HGC-27 cells was 1.13±0.09, higher than that of the control group (0.83±0.07, P=0.001), while the relative expression of HMGB1 in the nucleus was 0.79±0.06, lower than that of the control group (1.07±0.06, P=0.007). The phosphorylation level of HMGB1 reached 1.41±0.09, which was higher than that of the control group (0.97±0.10, P=0.031). The phosphorylation level of Akt was 11.16±0.06, higher than that of the control group (0.91±0.022, P=0.002). The phosphorylation level and nuclear translocation of HMGB1 induced by lactate decreased obviously after Akt inhibition; the proliferation and migration abilities induced by lactate were also obviously inhibited after Akt inhibition. In vivo, the HMGB1 level in the peripheral blood was (1 280.70±389.66) pg/ml in the lactate group, which was obviously higher than that in the control group (595.11±44.75) pg/ml (P=0.008), and the phosphorylation levels of HMGB1 and Akt in tumor tissues in the lactate group were obviously enhanced compared with the control group. Conclusion: Lactate induces HMGB1 release through enhancing HMGB1 phosphorylation via the Akt signaling pathway.
Mice ; Animals ; Stomach Neoplasms/pathology* ; Proto-Oncogene Proteins c-akt/metabolism* ; HMGB1 Protein/metabolism* ; Phosphorylation ; Lactic Acid ; Mice, Inbred BALB C ; Signal Transduction

Objective: To investigate the molecular mechanism of how lactate induces high mobility group box 1 (HMGB1) release. Methods: Gastric cancer HGC-27 cells were divided into the control group and the lactate group (The cells were treated with lactate for 6 h). The level of HMGB1 in the cell culture medium was detected by enzyme-linked immunosorbent assay (ELISA), the localization of HMGB1 was detected using laser confocal microscopy, and the nuclear translocation of HMGB1 was detected using the nucleoplasmic separation assay. The phosphorylation and acetylation levels of HMGB1 were determined by co-immunoprecipitation, and Western blot was used to measure the phosphorylation of Akt and protein kinase C (PKC). HGC-27 cells were first treated with lactate and LY294002, the inhibitor of Akt, and then the phosphorylation of HMGB1 and Akt was analyzed by co-immunoprecipitation and Western blot, respectively. The localization of HMGB1 in cells was detected by laser confocal microscopy. EdU and Transwell assays were used to detect the proliferation and migration abilities of HGC-27 cells, respectively. HGC-27 cells were then injected into the BALB/C null mice for subcutaneous tumor implantation. Mice in the lactate group were intraperitoneally injected with lactate (0.2 g/kg/2 d), while those in the control group were intraperitoneally injected with an equal amount of PBS for 20 consecutive days. ELISA was used to detect the HMGB1 levels in the blood samples taken from the medial canthus vein of the mice, while co-immunoprecipitation and Western blot were used to detect the phosphorylation of HMGB1 and Akt in tumor tissue proteins, respectively. Results: The release levels of HMGB1 in the lactate group were (2 995.00±660.91) pg/ml and (696.33±22.03) pg/ml, after lactate treatment for 6 h and 12 h, respectively, both higher than those in the control group (485.00±105.83) pg/ml (P<0.001 and P=0.028, respectively). After lactate treatment for 6 h, the relative expression of HMGB1 protein in the cytoplasm of HGC-27 cells was 1.13±0.09, higher than that of the control group (0.83±0.07, P=0.001), while the relative expression of HMGB1 in the nucleus was 0.79±0.06, lower than that of the control group (1.07±0.06, P=0.007). The phosphorylation level of HMGB1 reached 1.41±0.09, which was higher than that of the control group (0.97±0.10, P=0.031). The phosphorylation level of Akt was 11.16±0.06, higher than that of the control group (0.91±0.022, P=0.002). The phosphorylation level and nuclear translocation of HMGB1 induced by lactate decreased obviously after Akt inhibition; the proliferation and migration abilities induced by lactate were also obviously inhibited after Akt inhibition. In vivo, the HMGB1 level in the peripheral blood was (1 280.70±389.66) pg/ml in the lactate group, which was obviously higher than that in the control group (595.11±44.75) pg/ml (P=0.008), and the phosphorylation levels of HMGB1 and Akt in tumor tissues in the lactate group were obviously enhanced compared with the control group. Conclusion: Lactate induces HMGB1 release through enhancing HMGB1 phosphorylation via the Akt signaling pathway.
Mice ; Animals ; Stomach Neoplasms/pathology* ; Proto-Oncogene Proteins c-akt/metabolism* ; HMGB1 Protein/metabolism* ; Phosphorylation ; Lactic Acid ; Mice, Inbred BALB C ; Signal Transduction