TEAD4 activates PCSK9 to promote stomach adenocarcinoma cell stemness through fatty acid metabolism.

INTRODUCTION: This study attempted to investigate how PCSK9 influences the stemness of stomach adenocarcinoma (STAD) cells. METHODS: CCK-8 and sphere formation assays were used to detect cell viability and stemness. qRT-PCR and western blot were used to detect PCSK9 and TEAD4 expression. The binding relationship was verified by dual luciferase and chromatin immunoprecipitation (ChIP) assays. The effect of TEAD4 activating PCSK9 on the stemness of STAD cells was detected by bioinformatics, BODIPY 493/503, Oil red O, western blot, and kits. In vivo experiments verified the role of the TEAD4/PCSK9 axis in tumor formation in nude mice. RESULTS: PCSK9 and TEAD4 were highly expressed in STAD. PCSK9 was enriched in the FAM pathway. PCSK9 activated the fatty acid metabolism and promoted the proliferation and stemness of STAD cells. TEAD4 as a transcription factor upstream of PCSK9.Cell experiments revealed that knockdown of PCSK9 inhibited STAD cell stemness, whereas further addition of fatty acid inhibitors could attenuate the promoting effect on STAD cell stemness brought by STAD overexpression. Rescue experiments showed overexpressed PCSK9 exerted an inhibitory effect on the stemness of STAD cells brought by TEAD4 knockdown. The hypothesis that TEAD4/PCSK9 axis can promote STAD cell growth was confirmed by in vivo experiments. CONCLUSION: Transcription factor TEAD4 could activate PCSK9 to promote the stemness of STAD cells through FAM. These results added weight to the assumption that TEAD4/PCSK9 axis has the potential to be the therapeutic target that inhibits CSC in STAD.

miR-504 Promoted Gastric Cancer Cell Proliferation and Inhibited Cell Apoptosis by Targeting RBM4.

BACKGROUND: The purpose of this study was to explore the role and underlying mechanism of miR-504 and RBM4 in gastric cancer. METHODS: The qRT-PCR or Western blot was performed to determine the expressions of miR-504 and RBM4 in the gastric cancer tissues and normal tissues. Human SGC-7901 cells were transfected with miR-504 mimic/inhibitor or pcDNA-RBM4. Cell proliferation and cell apoptosis were assessed by colony formation assay and flow cytometry, respectively. Luciferase reporter gene assays were used to investigate interactions between miR-504 and RBM4 in SGC-7901 cells. RESULTS: The relative expression of miR-504 was significantly upregulated in the gastric cancer group (n = 25) than in the paired normal group (n = 25), but the relative RBM4 expression was remarkably downregulated in the gastric tumor group, compared with the normal group. Additionally, miR-504 overexpression increased the viability of gastric cancer cells. Moreover, RBM4 is a functional target of miR-504 in gastric cancer cells. miR-504 was further confirmed to promote SGC-7901 cell proliferation and inhibit cell apoptosis by downregulation RBM4 in vitro. CONCLUSIONS: miR-504 promotes gastric cancer cell proliferation and inhibits cell apoptosis by targeting RBM4, and this provides a potential diagnostic biomarker and treatment for patients with gastric cancer.

MiR-34a suppresses the proliferation and invasion of gastric cancer by modulating PDL1 in the immune microenvironment.

OBJECTIVES: As one of the most serious malignant carcinomas that threaten the life of sufferers constantly, gastric cancer has attracted a lot of interest among researchers. miR-34a, a member of hundreds of microRNAs (miRNAs), has been elucidated to exert a suppressive role in gastric cancer tumorgenesis based on previous extensive studies. Our study was performed with the aim to explore the functional effects of miR-34a and its predictive target programmed death ligand 1 (PDL1) in gastric cancer development. METHODS: We employed reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western Blot analysis to investigate the regulatory effect of miR-34a on PDL1 mRNA and the corresponding protein expression. The CCK-8 and colony formation assays were used to validate the influence of the combination of miR-34a and PDL1 on the proliferation of gastric tumor cells. Meanwhile, the migration and invasion of gastric tumor cells were measured using Transwell assay. RESULTS: PDL1 was targeted and negatively modulated by miR-34a. In addition, the re-expression of miR-34a suppressed the proliferation as well as the migration and invasion of gastric tumor cells, whereas PDL1 reduced the aforementioned inhibitory effect. CONCLUSIONS: PDL1 is the downstream gene of miR-34a, which can act as an anti-oncogene in gastric cancer. The miR-34a/PDL1 axis might provide a promising anticancer therapeutic approach for the clinical diagnosis, treatment, and prognosis of gastric cancer.

Naringin inhibits colorectal cancer cell growth by repressing the PI3K/AKT/mTOR signaling pathway.

In recent years, the incidence of colorectal cancer (CRC) has increased and research into new treatment methods for CRC has become a hot topic. Naringin has an inhibitory effect on the PI3k/AKT/mTOR signaling pathway in various tumor cell types and the effect of naringin is closely related to the occurrence and proliferation of tumor cells. The aim of this present study was to investigate whether naringin could inhibit the proliferation of CRC cells by inhibiting the PI3K/AKT/mTOR signaling pathway. This could provide a more mechanism-based treatment for CRC. MTT assays were used to detect the proliferation of CRC cells treated with various concentrations of naringin. The degree of apoptosis and the expression of apoptosis-related proteins (Bcl-2 and Bax) in CRC cells stimulated by naringin was detected using flow cytometry and western blot assays, respectively. The expression levels of PI3K/AKT/mTOR-related proteins [PI3K, AKT, mTOR, phosphorylated (p)-PI3K, p-AKT and p-mTOR] after naringin stimulation in CRC cells were detected using western blot assays. Naringin inhibited the proliferation of CRC cells in a dose-dependent manner. Naringin promoted the apoptosis of CRC cells and inhibited the activation of the PI3K/AKT/mTOR signaling pathway in a dose-dependent manner. The results demonstrated that naringin may be a promising therapeutic agent for the treatment of CRC, which may inhibit the proliferation of CRC cells and induce apoptosis by inhibiting the PI3K/AKT/mTOR signaling pathway.

Nakamurella flava sp. nov., a novel endophytic actinobacterium isolated from Mentha haplocalyx Briq.

A Gram-stain-positive, aerobic, coccus-shaped, non-spore-forming actinobacterium, designated strain N5BH11T, was isolated from a surface-sterilized sample of Mentha haplocalyx Briq. collected from Guizhou, PR China and tested by a polyphasic approach to determine its taxonomic position. Strain N5BH11T grew optimally at 30 °C, pH 6.0-7.0. Substrate mycelia and aerial mycelia were not formed, and no diffusible pigments were observed on the media tested. Phylogenetic analysis based on 16S rRNA gene sequence suggested that strain N5BH11T belonged to the genus Nakamurella and had the highest 16S rRNA gene sequence similarity to Nakamurella flavida DS-52T (98.1 %). The DNA G+C content of strain N5BH11T was 71.6 mol%. The average nucleotide identity values between strain N5BH11T and the type strains of Nakamurella panacisegetis, Nakamurella multipartita and Nakamurella lactea were 74.0, 76.5 and 73.6 %, respectively. The estimated DDH values between strain N5BH11T and the type strains of N. panacisegetis, N. multipartita and N. lactea were 20.3%, 21.4 and 20.2 %, respectively. The cell-wall peptidoglycan contained meso-diaminopimelic acid, and MK-8(H4) was the predominant menaquinone. The predominant polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine and unidentified phospholipids. The major fatty acids were iso-C15 : 0, anteiso-C15 : 0, C16 : 0 and C16 : 1ω7c. On the basis of the results of phylogenetic analysis and phenotypic and chemotaxonomic characteristics, strain N5BH11T represents a novel species of the genus Nakamurella, for which the name Nakamurella flava sp. nov. is proposed. The type strain is N5BH11T (=KCTC 49196T=CGMCC 4.7524T).

RNA-Binding Motif 4 (RBM4) Suppresses Tumor Growth and Metastasis in Human Gastric Cancer.

BACKGROUND Dysregulation of the splicing activator, RNA-binding motif 4 (RBM4), has recently been reported to be involved in the progression of several cancers. However, the mechanisms that underpin the activity of RBM4 in gastric cancer (GC) remain unknown. The purpose of our study was to explore how RBM4 affects the biological behavior of GC through in vivo and in vitro experiments. MATERIAL AND METHODS Western blot and flow cytometry analyses were used to investigate the RBM4 protein levels in normal gastric epithelial cells and 5 types of GC cells. Cell Counting Kit-8 assay, flow cytometry analysis, wound-healing, and migration and invasion assays were evaluated in vitro in BGC823 and MGC803 GC cells. A xenograft tumor model was used to assess whether RBM4 inhibits GC growth in vivo. Mitogen-activated protein kinase (MAPK) protein levels were determined using western blot analyses. RESULTS Our study revealed that RBM4 protein was downregulated in GC cells. Re-expression of RBM4 inhibited the proliferation, migration, and invasion of GC cells, while promoting apoptosis. Thus, the overexpression of RBM4 can inhibit tumor growth in GC mouse models. We also report that RBM4 was involved in the activation of MAPK-dependent signaling pathways in human GC. CONCLUSIONS It is hoped that these findings will improve our understanding of GC pathogenesis while also helping us to explore the feasibility of RBM4-targeted therapy for GC treatment.

Brachybacterium endophyticum sp. nov., a novel endophytic actinobacterium isolated from bark of Scutellaria baicalensis Georgi.

A Gram-positive, aerobic, coccus-shaped, non-spore-forming actinobacterium, designated strain M1HQ-2T, was isolated from a surface-sterilized bark of Scutellaria baicalensis Georgi collected from Guizhou, China and tested using a polyphasic approach to determine its taxonomic position. Strain M1HQ-2T grew at 4-37 °C (optimum, 30 °C), pH 5.0-11.0 (pH 8.0) and in the presence of 0-15 % (w/v) NaCl (1-3 %). Substrate mycelia and aerial mycelia were not formed, and diffusible pigments were not observed on any media tested. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain M1HQ-2T belonged to the genus Brachybacterium and had the highest 16S rRNA gene sequence similarity of 97.6 % to Brachybacteriumsquillarum M-6-3T. Strain M1HQ-2T contained MK-7 as the dominant menaquinone. The cell-wall peptidoglycan contained meso-diaminopimelic acid. The polar lipids profile of strain M1HQ-2T contained diphosphatidylglycerol, phosphatidylglycerol, an unidentified phospholipid and an unidentified lipid. The predominant fatty acids were anteiso-C15 : 0 and anteiso-C17 : 0. The DNA G+C content of strain M1HQ-2T was 71.0 mol%. The average nucleotide identity value between strain M1HQ-2T and type strain of Brachybacterium sacelli was 76.7 %. The estimated DNA-DNA hybridization value between strain M1HQ-2T and type strain of B. sacelli was 20.6 %. On the basis of phylogenetic analysis, chemotaxonomic characteristics and phenotypic data, strain M1HQ-2T represents a novel species of the genus Brachybacterium, for which the name Brachybacteriumendophyticum sp. nov. is proposed. The type strain is M1HQ-2T (=KCTC 49087T=CGMCC 1.16391T).

Prognostic value of microRNA-126 and CRK expression in gastric cancer.

BACKGROUND: MicroRNA (miR)-126, acting as a tumor suppressor, has been reported to inhibit the invasion of gastric cancer cells in part by targeting v-crk sarcoma virus CT10 oncogene homologue (CRK). The aim of this study was to investigate the clinical significance of miR-126/CRK axis in gastric cancer. METHODS: miR-126 and CRK mRNA expression levels were detected by real-time quantitative reverse transcription polymerase chain reaction in 220 self-pairs of gastric cancer and adjacent noncancerous tissues. RESULTS: Expression levels of miR-126 and CRK mRNA in gastric cancer tissues were, respectively, lower and higher than those in adjacent noncancerous tissues (both P<0.001). Low miR-126 expression and high CRK expression, alone or in combination, were all significantly associated with positive lymph node and distant metastases and advanced TNM stage of human gastric cancer (all P<0.05). We also found that the overall survival rates of the patients with low miR-126 expression and high CRK expression were, respectively, shorter than those with high miR-126 expression and low CRK expression. Interestingly, miR-126-low/CRK-high expression was associated with a significantly worse overall survival of all miR-126/CRK groups (P<0.001). Moreover, multivariate analysis identified miR-126 and/or CRK expression as independent prognostic factors for patients with gastric cancer. Notably, the prognostic relevance of miR-126 and/or CRK expression was more obvious in the subgroup of patients with TNM stage IV. CONCLUSION: Dysregulation of miR-126/CRK axis may promote the malignant progression of human gastric cancer. miR-126 and CRK combined expression may serve as an independent predictor of overall survival in patients with advanced gastric cancer.

Prognostic significance of combined microRNA-206 and CyclinD2 in gastric cancer patients after curative surgery: A retrospective cohort study.

AIM: To investigate associations of microRNA (miR)-206 and CyclinD2 (CCND2) expression, alone or in combination, with clinicopathological characteristics and patients' prognosis in gastric cancer. METHODS: MiR-206 and CCND2 mRNA expression levels were detected by real-time quantitative RT-PCR in 220 self-pairs of gastric cancer and adjacent non-cancerous tissues. RESULTS: Compared with the adjacent non-cancerous tissues, the expression levels of miR-206 and CCND2 mRNA were respectively reduced and elevated in gastric cancer tissues dramatically (both P<0.001). Notably, the expression levels of miR-206 in gastric cancer tissues were negatively correlated with those of CCND2 mRNA significantly (r=-0.463, P<0.001). Then, statistical analysis showed that low miR-206 expression and high CCND2 expression, alone or in combination, were all significantly associated with great depth of invasion, positive lymph node and distant metastases, and advanced TNM stage of human gastric cancer (all P<0.05). After that, we also found that the overall survivals of the patients with low miR-206 expression and high CCND2 expression were respectively shorter than those with high miR-206 expression and low CCND2 expression. More interestingly, miR-206-low/CCND2-high expression was associated with a significantly worst overall survival of all miR-206/CCND2 groups (P<0.001). Furthermore, multivariate analysis identified miR-206 and/or CCND2 expression as independent prognostic factors for overall survival in patients with gastric cancer. CONCLUSION: Our data provide evidence that the dysregulation of miR-206-CCND2 axis may contribute to the aggressive progression and poor prognosis of human gastric cancer in clinical settings. Combined detection of their expression might be particularly helpful for surveillance of disease progression and treatment stratification.