LncRNA SLC7A11-AS1 promotes the progression of hepatocellular carcinoma by mediating KLF9 ubiquitination.

Hepatocellular carcinoma (HCC) is a malignant tumor, which seriously threatens the life of patients. LncRNA SLC7A11-AS1 was reported to be abnormally expressed in HCC. Here, the functions and relative molecular regulatory mechanism of SLC7A11-AS1 in HCC were investigated. Nude mice and HCC cells were used as the experimental subjects. Knockdown or overexpression of exogenous genes was conducted in HCC cells. RT-qPCR, IHC, and western blot were employed to evaluate the abundance of genes and proteins. The malignant behaviors were evaluated using CCK-8, clone formation, wound-healing, and Transwell. The locations of SLC7A11-AS1 and KLF9 in cells were determined by FISH and IF assays. The total m6A level was evaluated by dot-blot assay. m6A modification of SLC7A11-AS1 was detected using RNA MeRIP. The interactions among molecules were validated by RIP, ChIP, dual luciferase reporter assay, and co-IP. SLC7A11-AS1 was elevated apparently in HCC cells and HCC tissues from mice. SLC7A11-AS1 silencing could suppress HCC progression, which was validated in in vivo and in vitro experiments. Furthermore, METTL3 mediated m6A modification of SLC7A11-AS1 to elevate its expression. In addition, SLC7A11-AS1 downregulated KLF9 expression by affecting STUB1-mediated ubiquitination degradation and KLF9 enhanced PHLPP2 expression to inactivate the AKT pathway. Eventually, rescue experiments revealed that KLF9 knockdown abolished SLC7A11-AS1 silencing-mediated suppression of HCC progression in vivo and in vitro. Our results unveiled that m6A-modified SLC7A11-AS1 promoted HCC progression by regulating the STUB1/KLF9/PHLPP2/AKT axis, indicating that targeting SLC7A11-AS1 might alleviate HCC progression.

Dipeptidyl peptidase-8 induces sorafenib resistance via binding with c-Rel to mediate NF-κB signaling in hepatocellular carcinoma.

Sorafenib is the important first-standard drug for patients with advanced hepatocellular carcinoma (HCC). A major obstacle to successful treatment is sorafenib resistance. However, the mechanism of sorafenib resistance is unclear. The present study aimed to determine the involvement of dipeptidyl peptidase-8 (DPP8) in sorafenib resistance. DPP8 expression was detected using quantitative real-time PCR (qPCR) and western blot analysis. The effect of DPP8 on sorafenib resistance was examined using terminal deoxynulceotidyl transferase nick-end-labeling (TUNEL), colony formation, flow cytometry, luciferase reporter, immunofluorescence, and immunoprecipitation (IP) assays. We found that DPP8 mRNA and protein levels were dramatically upregulated in HCC. Gene set enrichment analysis (GSEA) illustrated that DPP8 might be involved in apoptosis regulation. Downregulation of DPP8 substantially promoted the sensitivity of HCC cells to sorafenib. Further analysis showed that DPP8 might regulate nuclear factor kappa B (NF-κB) signaling, which was confirmed using a luciferase reporter assay. Downregulation of DPP8 decreased the expression levels of downstream genes of the NF-κB pathway. IP showed that DPP8 can interact with NF-κB subunit c-Rel, an important protein of NF-κB signaling. Finally, a drug combination of sorafenib and Val-boroPro induced higher mortality of HCC cells than sorafenib alone in DPP8-upregulated cells. Our findings indicated that using the inhibitor Val-boroPro might be a promising method to enhance sorafenib sensitivity in advanced HCC.

Amplification of DDR2 mediates sorafenib resistance through NF-κB/c-Rel signaling in hepatocellular carcinoma.

Sorafenib was the first systemic therapy approved by the Food and Drug Administration to treat advanced hepatocellular carcinoma (HCC). However, sorafenib therapy is frequently accompanied by drug resistance. We aimed to explore the mechanisms of sorafenib resistance and provide feasible solutions to increase the response to sorafenib in patients with advanced HCC. The expression profile of discoidin domain receptor 2 (DDR2) in HCC tissues and cells was detected using quantitative real-time PCR (qPCR) and western blotting assays. The effects of DDR2 on sorafenib resistance were examined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, colony formation, TdT-mediated dUTP nick end labeling, and flow cytometry assays. The effect of DDR2 on the nuclear factor kappa B (NF-κB) signaling pathway was evaluated by luciferase reporter, immunofluorescence, qPCR and flow cytometry assays. We demonstrated that DDR2 expression was dramatically upregulated in sorafenib-resistant HCC tissues relative to sensitive tissues. Downregulation of DDR2 sensitized HCC cell lines to sorafenib cytotoxicity. Further analysis showed that DDR2 could increase the nuclear location of REL proto-oncogene, a NF-κB subunit, to mediate NF-κB signaling. Blocking NF-κB signaling using the NF-κB signaling inhibitor, bardoxolone methyl, increased the response of HCC cells to sorafenib. Further analysis showed that DNA amplification of DDR2 is an important mechanism leading to DDR2 overexpression in HCC. Our results demonstrated that DDR2 is a potential therapeutic target in patients with HCC, and targeting DDR2 represents a promising approach to increase sorafenib sensitivity in patients with HCC.

Expression and prognostic significance of thrombospondin gene family in gastric cancer.

BACKGROUND: Thrombospondins (THBSs) are glycoproteins expressed in the extracellular matrix (ECM) and have critical roles in tumor development and metastasis. However, the diverse expression patterns and prognostic roles of distinct THBS genes in gastric cancer have not been fully elucidated. In the current study, we aimed to investigate the expression patterns of THBSs in gastric cancer (GC) and determine whether they are prognostic markers for this malignancy. METHODS: mRNA expression status and genetic mutations of THBS family members were performed by using ONCOMINE, UCSC Xena browser, GEPIA, and cBioPortal databases. Prognostic values and function enrichment analysis of the members were assessed via Kaplan-Meier plotter and Metascape. RESULTS: we found that the mRNA expression of THBS1, THBS2, THBS4, and COMP were higher in patients with GC tissues than those in normal gastric mucosa and there was no difference in the mRNA expression of THBS3 between GC and normal tissue. Survival analysis revealed that mRNA levels of THBSs were strongly related to worse OS in GC patients (P<0.05). Overexpression of THBSs indicated poor OS in stage III/IV GC and high expression of THBS1, THBS3, THBS4, and COMP were related to worse OS in stage II GC. CONCLUSIONS: Bioinformatics analysis revealed a better understanding the value of THBS family members in GC and suggest that THBSs might serve as potential prognostic biomarkers for GC.

[Efflect of miR-34a-Tangeted Regulation of HDACI on Apoptosis of AML Cells].

OBJECTIVE: To investigate the regulation of miR-34a on HDAC1 expression and its effect on the apoptosis of acute myeloid leukemia (AML) cells. METHODS: miR-34a mimics, miR-34a inhibitor and miR-34a scramble were transfected into HL-60 cells. The effects of miR-34a expression levels on proliferation and apoptosis of HL-60 cell were detected by CCK8 assay and flow cytometry respectively. The expression of HDAC1 protein was assessed by Western blot after regulating miR-34a expression, the 3'UTR of HDAC1 was cloned and ligated to construct a dual luciferase reporter vector, and then the dual luciferase reporter assay was applied to verify the target of miR-34a, the expression vector pcDNA3.1-HDAC1 was constructed, the interaction of miR-34a and HDAC1 was analyzed by reversion test. RESULTS: miR-34a over-expression could inhibit the proliferation of HL-60 cells and induce their apoptosis. Bioinformatics analysis indicated that the HDAC1 was a target gene of miR-34a. Western blot indicated that miR-34a overexpression down-regulated the expression of HDAC1. Dual luciferase reporter assay and reversion test showed that miR-34a could act at the 3-UTR of HDAC1 gene to regulate its expression. CONCLUSION: miR-34a promotes the apoptosis of HL-60 cells via regulating HDAC1 expression.

GSK-3ß suppresses the proliferation of rat hepatic oval cells through modulating Wnt/ß-catenin signaling pathway.

AIM: Glycogen synthase kinase 3ß (GSK-3ß) plays a crucial role in hepatic biology, including liver development, regeneration, proliferation and carcinogenesis. In this study we investigated the role of GSK-3ß in regulation of growth of hepatic oval cells in vitro and in liver regeneration in partially hepatectomized rats. METHODS: WB-F344 cells, the rat hepatic stem-like epithelial cells, were used as representative of oval cells. Cell viability was examined using a WST-8 assay. The cells were transfected with a recombinant lentivirus expressing siRNA against GSK-3ß (GSK-3ßRNAiLV) or a lentivirus that overexpressed GSK-3ß (GC-GSK-3ßLV). Adult rats underwent partial (70%) hepatectomy, and liver weight and femur length were measured at d 7 after the surgery. The expression of GSK-3ß, phospho-Ser9-GSK-3ß, ß-catenin and cyclin D1 was examined with immunoblotting assays or immunohistochemistry. RESULTS: Treatment of WB-F344 cells with the GSK-3ß inhibitor SB216763 (5 and 10 µmol/L) dose-dependently increased the levels of phospho-Ser9-GSK-3ß, but not the levels of total GSK-3ß, and promoted the cell proliferation. Knockout of GSK-3ß with GSK-3ßRNAiLV increased the cell proliferation, whereas overexpression of GSK-3ß with GC-GSK-3ßLV decreased the proliferation. Both SB216763 and GSK-3ßRNAiLV significantly increased the levels of ß-catenin and cyclin D1 in the cells, whereas GSK-3ß overexpression decreased their levels. In rats with a partial hepatectomy, administration of SB216763 (2 mg/kg, ip) significantly increased the number of oval cells, the levels of phospho-Ser9-GSK-3ß, ß-catenin and cyclin D1 in liver, as well as the ratio of liver weight to femur length at d 7 after the surgery. CONCLUSION: GSK-3ß suppresses the proliferation of hepatic oval cells by modulating the Wnt/ß-catenin signaling pathway.

Lentiviral vector-mediated down-regulation of IL-17A receptor in hepatic stellate cells results in decreased secretion of IL-6.

AIM: To investigate the mechanism of interleukin (IL)-6 secretion through blocking the IL-17A/IL-17A receptor (IL-17RA) signaling pathway with a short hairpin RNA (shRNA) in hepatic stellate cells (HSCs) in vitro. METHODS: HSCs were derived from the livers of adult male Sprague-Dawley rats. IL-6 expression was evaluated using real-time quantitative polymerase chain reaction and enzyme linked immunosorbent assay. The phosphorylation activity of p38 mitogen activated protein kinases (MAPK) and extracellular regulated protein kinases (ERK) 1/2 upon induction by IL-17A and suppression by IL-17RA shRNA were examined using Western blotting. RESULTS: IL-6 expression induced by IL-17A was significantly increased compared to control in HSCs (P < 0.01 in a dose-dependent manner). Suppression of IL-17RA using lentiviral-mediated shRNA inhibited IL-6 expression induced by IL-17A compared to group with only IL-17A treatment (1.44 ± 0.17 vs 4.07 ± 0.43, P < 0.01). IL-17A induced rapid phosphorylation of p38 MAPK and ERK1/2 after 5 min exposure, and showed the strongest levels of phosphorylation of p38 MAPK and ERK1/2 at 15 min in IL-17A-treated HSCs. IL-6 mRNA expression induced by IL-17A (100 ng/mL) for 3 h exposure was inhibited by preincubation with specific inhibitors of p38 MAPK (SB-203580) and ERK1/2 (PD-98059) compared to groups without inhibitors preincubation (1.67 ± 0.24, 2.01 ± 0.10 vs 4.08 ± 0.59, P < 0.01). Moreover, Lentiviral-mediated IL-17RA shRNA 1 inhibited IL-17A-induced IL-6 mRNA expression compared to random shRNA in HSCs (1.44 ± 0.17 vs 3.98 ± 0.68, P < 0.01). Lentiviral-mediated IL-17RA shRNA 1 inhibited phosphorylation of p38 MAPK and ERK1/2 induced by 15 min IL-17A (100 ng/mL) exposure. CONCLUSION: Down-regulation of the IL-17RA receptor by shRNA decreased IL-6 expression induced by IL-17A via p38 MAPK and ERK1/2 phosphorylation in HSCs. Suppression of IL-17RA expression may be a strategy to reduce the inflammatory response induced by IL-17A in the liver.

[Effects of glycogen synthase kinase 3ß overexpression in rat and glycogen synthase kinase 3ß inhibitor SB-216763 on proliferation of hepatic oval cells].

OBJECTIVE: To research the effects of glycogen synthase kinase (GSK3ß) overexpression and GSK3ß inhibitor SB-216763 on the proliferation of hepatic oval cells in rats and its regulatory mechanisms by Wnt signaling pathway. METHODS: The hepatic oval cells WBF-344 were divided into the blank control group, GSK3ß over-expression group, DMSO control group and GSK3ß inhibitor groups, while the inhibitor groups set up three concentration gradients, that was 1, 5, 10 µmol/L. Using the GSK3ß over-expression lentivirus, which had been identified correctly, and SB-216763 dealt with the cells WBF-344. The cells morphology of each group was observed under the phase contrast inverted microscope, and the expression of fluorescence in the lentivirus-transfected group was observed under the fluorescent microscope. The proliferation of each group cells was tested by CCK8 kits. The cells' apoptosis was detected by AnnexinV-FITC/PI kits. The expression of GSK3ß, ß-catenin and cyclin D1 were detected by Western blot. RESULTS: The cells of GSK3ß over-expression group were fewer and obvious aging. However, in each inhibitor added group, the cells' division and proliferation was vigorous, and the condition was good. Moreover, the cells' proliferation was getting stronger with the concentration of SB-216763 increasing. A large number of green fluorescence was expressed in the lentivirus-transfected cells. The cells' proliferation in GSK3ß over-expression group restrained (t = 7.178, P < 0.01, as compared with control), while the cells' proliferation was vigorous in inhibitor groups (F = 45.030, P < 0.01, as compared with control). Flow Cytometry showed that the cells apoptosis was significant in GSK3ß over-expression group. Western blot showed that the expression of GSK3ß was increased, while the expression of ß-catenin and cyclin D1 was decreased in the over-expression group. The expression of GSK3ß had no significant difference among the control group and inhibitor groups. However, the expression of ß-catenin and cyclin D1 was significantly increased with the concentration of SB-216763 increasing. CONCLUSIONS: The overexpression of GSK3ß can inhibit the Wnt signaling pathway, thus restrain the cells' proliferation and promotes apoptosis. SB-216763 can activate the Wnt pathway, thus promotes cells' proliferation.

Angiogenesis and clinicopathologic characteristics in different hepatocellular carcinoma subtypes defined by EpCAM and α-fetoprotein expression status.

Recently, two hepatic lineage markers epithelial cell adhesion molecule (EpCAM) and α-fetoprotein (AFP) were used to classify hepatocellular carcinoma (HCC) into four subtypes with prognostic implication. In the present study, we further evaluated the clinicopathologic and angiogenic characteristics among these HCC subtypes. EpCAM expression was investigated by immunohistochemistry in 115 HCC primary tumors. Based on EpCAM immunostaining and serum AFP levels, 115 HCC cases were classified into four subtypes: EpCAM+AFP+ (26.1%), EpCAM-AFP+ (20.0%), EpCAM+AFP- (20.8%), and EpCAM-AFP- (33.1%). EpCAM+AFP+ and EpCAM-AFP+ HCC were associated with late TNM stages and high frequencies of venous invasion, whereas EpCAM+AFP- and EpCAM-AFP- subtypes were associated with early TNM stages and low frequencies of venous invasion. Furthermore, EpCAM+AFP+ HCC had a significantly higher microvessel density (MVD) and higher level of VEGF (Vascular epithelial growth factor) expression than the other three subtypes. In conclusion, our study indicated that subtype classification of HCC based on EpCAM and AFP status had clinicopathologic and biologic implications in aggressive phenotype and angiogenesis. We also suggest that the EpCAM+AFP+ HCC patients might be potential therapeutic candidates for anti-angiogenesis therapy.

Inhibitory effects of tanshinone II-A on invasion and metastasis of human colon carcinoma cells.

AIM: To investigate the effects and possible mechanisms of tanshinone II-A, an alcohol extract of the root of Salvia miltiorrhiza Bunge, on tumor invasion and metastasis of human colon carcinoma (CRC) cells. METHODS: The effects of tanshinone II-A on invasion and metastasis of CRC cell lines HT29 and SW480 were evaluated by in vitro and in vivo assays. Western blotting was used to investigate possible molecular mechanisms of tanshinone II-A anti-cancer actions. RESULTS: Tanshinone II-A inhibited migration and invasion of CRC cells in a dose-dependent manner. The inhibitory effect also depended on time, with the most significant effects observed at 72 h. Tanshinone II-A also significantly inhibited in vivo metastasis of colon carcinoma SW480 cells. It inhibited in vitro and in vivo invasion and metastasis of CRC cells by reducing levels of urokinase plasminogen activator (uPA) and matrix metalloproteinases (MMP)-2 and MMP-9, and by increasing levels of tissue inhibitor of matrix metalloproteinase protein (TIMP)-1 and TIMP-2. Tanshinone II-A was also shown to suppress the nuclear factor-kappaB (NF-kappaB) signal. CONCLUSION: Tanshinone II-A inhibited in vitro and in vivo invasion and metastasis of CRC cells. The effect resulted from changes in the levels of uPA, MMP-2, MMP-9, TIMP-1 and TIMP-2, and apparent inhibition of the NF-kappaB signal transduction pathway.