STX2 drives colorectal cancer proliferation via upregulation of EXOSC4.

AIMS: To explore the biological function and mechanism of Syntaxin2 (STX2) in Colorectal cancer (CRC) proliferation. MAIN METHODS: A series of gain- and loss-of-function analysis were conducted the to explore the biological function of STX2 in CRC proliferation in vivo and in vitro. Western blot, Co-immunoprecipitation (Co-IP) and the functional analyses were taken to analyze the regulative role of STX2 on Exosome Complex 4 (EXOSC4) in CRC proliferation; Immunohistochemistry (IHC) and Real-time quantitative polymerase chain reaction (qPCR) were used to further verify the relationship between the expression of STX2 and EXOSC4 in human CRC samples. KEY FINDINGS: Our study revealed that the over-expression of STX2 promoted CRC proliferation, while knockdown of STX2 repressed CRC proliferation; STX2 promoted CRC proliferation via increasing EXOSC4 protein; There was a positive correlation between STX2 and EXOSC4 expression. SIGNIFICANCE: The current data verify that STX2 drives the proliferation of CRC via increasing the expression of EXOSC4.

EPAS1 targeting by miR-152-3p in Paclitaxel-resistant Breast Cancer.

Background: Paclitaxel plays a pivotal role in the chemotherapy of breast cancer, but resistance to this drug is an important obstacle in the treatment. It is reported that microRNA-152-3p (miR-152-3p) is involved in tamoxifen resistance in breast cancer, but whether it is involved in paclitaxel resistance in breast cancer remains unknown. Materials and methods: We examined the expression of miR-152-3p in breast cancer tissues and cells by qRT-PCR. After transfecting paclitaxel-resistant MCF-7/TAX cells with miR-152-3p mimics, we analyzed the function of miR-152-3p in these cells by MTT assay and flow cytometry. We screened the target gene, endothelial PAS domain-containing protein 1 (EPAS1), using bioinformatics analysis and verified it with the dual luciferase reporter gene experiment. The relationship between EPAS1 and miR-152-3p and their roles in paclitaxel resistance of breast cancer were further investigated using RNA interference and transfection techniques. Results: The expression of miR-152-3p in normal breast tissues and cells was markedly higher than that in breast cancer. Overexpression of miR-152-3p decreased the survival rate and increased the apoptosis rate and sensitivity of MCF-7/TAX cells to paclitaxel. We confirmed that EPAS1 is the target of miR-152-3p and is negatively regulated by this miRNA. Moreover, transfection with EPAS1 siRNA enhanced the susceptibility and apoptosis rate of MCF-7/TAX cells to paclitaxel. Co-transfection of miR-152-3p mimics and EPAS1 increased paclitaxel sensitivity and apoptosis induced by the drug. Conclusion: miR-152-3p inhibits the survival of MCF-7/TAX cells and promotes their apoptosis by targeting the expression of EPAS1, thereby, enhancing the sensitivity of these breast cancer cells to paclitaxel.

KISS-1 inhibits the proliferation and invasion of gastric carcinoma cells.

AIM: To investigate the function of the KISS-1 gene in gastric carcinoma cells and to explore its potential mechanism. METHODS: A KISS-1 eukaryotic expression vector was constructed and transfected into BGC-823 cells. Resistant clones were obtained through G418 selection. reverse transcription-polymerase chain reaction and western blotting were used to detect KISS-1 and matrix metalloproteinase-9 (MMP-9) expression in transfected cells. The growth of transfected cells was investigated by 3-(4, 5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) proliferation assays, and the cells' invasive potential was analyzed by basement membrane (Matrigel) invasion assays. The anti-tumor effects of KISS-1 were tested in vivo using allografts in nude mice. RESULTS: The expression level of KISS-1 mRNA and protein in BGC-823/KISS-1 transfected cells were significantly higher than in BGC-823/pcDNA3.1 transfected cells (P < 0.05) or the parental BGC-823 cell line (P < 0.05). The expression level of MMP-9 mRNA and protein in BGC-823/KISS-1 were significantly less than in BGC-823/pcDNA3.1 (P < 0.05) or BGC-823 cells (P < 0.05). MTT growth assays show the proliferation of BGC-823/KISS-1 cells at 48 h (0.642 ± 0.130) and 72 h (0.530 ± 0.164) were significantly reduced compared to BGC-823/pcDNA3.1 (0.750 ± 0.163, 0.645 ± 0.140) (P < 0.05) and BGC-823 cells (0.782 ± 0.137, 0.685 ± 0.111) (P < 0.05). Invasion assays indicate the invasive potential of BGC-823/KISS-1 cells (16.50 ± 14.88) is significantly reduced compared to BGC-823/pcDNA3.1 (20.22 ± 14.87) (P < 0.05) and BGC-823 cells after 24 h (22.12 ± 16.12) (P < 0.05). In vivo studies demonstrate the rate of pcDNA3.1-KISS-1 tumor growth is significantly slower than pcDNA3.1 and control cell tumor growth in nude mice. Furthermore, tumor volume of pcDNA3.1-KISS-1 tumors (939.38 ± 82.08 mm(3)) was significantly less than pcDNA3.1 (1250.46 ± 44.36 mm(3)) and control tumors (1284.36 ± 55.26 mm(3)) (P < 0.05). Moreover, the tumor mass of pcDNA3.1-KISS-1 tumors (0.494 ± 0.84 g) was significantly less than pcDNA3.1 (0.668 ± 0.55 g) and control tumors (0.682 ± 0.38 g) (P < 0.05). CONCLUSION: KISS-1 may inhibit the proliferation and invasion of gastric carcinoma cells in vitro and in vivo through the downregulation of MMP-9.

[Role of nuclear factor-kappaB in apoptosis pathway of HUVEC].

AIM: To investigate the role of nuclear factor-kappaB in apoptosis pathway of HUVEC. METHODS: The cell lines of HUVEC cultured in vitro were divided into three groups: normal control group, Ang II group, and Gliotoxin group. We investigated the effects of Ang II (0.01 micromol/L, 0.1 micromol/L, 1 micromol/L and 10 micromol/L) on the viability of HUVEC with modified MTT. Then agarose gel electrophoresis and flow cytometry were applied to detect the apoptosis of HUVEC. Finally, the nuclear translocation of NF-kappaB subunit p65 was evaluated by immunocytochemistry. RESULTS: The viability of HUVEC decreased significantly after incubated with 10 micromol/L Ang II for 24 hours. The results of DNA agarose gel and flow cytometry showed that 10 micromol/L Ang II induced the apoptosis of HUVEC, and the apoptosis rate was significantlyhigher than normal control group (P < 0.05). 0.1 mg/L Gliotoxin antagonized this effect of Ang II. The results of immunocytochemistry suggested that NF-kappaB was activated in HUVEC induced by 10 micromol/L Ang II. In contrast, Gliotoxin inhibited the activation of NF-kappaB in HUVEC induced by Ang II. CONCLUSION: (1) Ang II can induce the apoptosis of HUVEC, while the inhibitor of NF-kappaB, Gliotoxin, can antagonize the effect of Ang II. (2) NF-kappaB may play an important role in apoptosis pathway of HUVEC induced by Ang II.