Downregulation of SUMO2 inhibits hepatocellular carcinoma cell proliferation, migration and invasion.

This study aimed to evaluate the prognostic value and biological function of small ubiquitin-like modifier 2 (SUMO2) in hepatocellular carcinoma (HCC). SUMO2 expression in HCC tissues was markedly higher than that in normal liver tissues, and patients with high SUMO2 expression had significantly shorter median overall survival than those with low SUMO2 expression. Furthermore, SUMO2 expression was closely correlated with lymph node metastasis and vascular invasion and was a predictor of poor prognosis. The knockdown of SUMO2 in two HCC cell lines (SMMC-7721 and Bel-7404) dramatically suppressed their proliferation, migration and invasion. Western blot analysis showed that the downregulation of SUMO2 significantly reduced the expression of Ki-67, matrix metalloproteinase-9 (MMP-9) and vascular endothelial growth factor (VEGF) in SMMC-7721 and Bel-7404 cells. Similarly, quantitative reverse transcription-PCR revealed consistently decreased expression of MMP-9 and VEGF. Our data suggest that SUMO2 promotes proliferation, migration and invasion of HCC cells via mechanisms involving MMP-9 and VEGF. Therefore, SUMO2 may be a prognostic factor and a promising therapeutic target for patients with HCC.

Long non-coding RNA MT1DP interacts with miR-365 and induces apoptosis of nucleus pulposus cells by repressing NRF-2-induced anti-oxidation in lumbar disc herniation.

BACKGROUND: This study investigated the effects of the long non-coding (lnc) RNA MT1DP on the apoptosis of nucleus pulposus (NP) cells. The interactions between MT1DP and the microRNA miR-365, and its effects on the anti-oxidant activity of nuclear factor erythroid 2-related factor 2 (NRF-2) were investigated in lumbar disc herniation (LDH). METHODS: Human degenerative intervertebral disc NP tissues were obtained from 10 patients with LDH who underwent lumbar spine surgery. Normal intervertebral disc NP tissues were obtained from 10 patients with lumbar vertebrae fractures and used as negative controls (NCs). RESULTS: The gene expressions of MT1DP and miR-365 in human degenerative disc NP tissues and nucleus pulposus cells (NPCs) were significantly increased, while the level of NRF-2 was significantly decreased. Overexpression of MT1DP and miR-365 (MT1DP + miR-365) and inhibition of NRF-2 suppressed NP cell viability and induced apoptosis. MT1DP + miR-365 caused inflammation in NP cells by damaging the mitochondrial membrane. The combination of lnc-MT1DP and miR-365 reduced cell mitochondrial function and led to a decrease in the ability of cells to elimination reactive oxygen species (ROS). CONCLUSIONS: The combination of lnc-MT1DP and miR-365 damaged the cell mitochondrial membrane, reduced mitochondrial function and the ability to eliminate ROS, increased cell apoptosis, and caused LDH.

Melatonin inhibits lung metastasis of gastric cancer in vivo.

AIM: Melatonin shows therapeutic benefits in gastric cancer, but the mechanism underlying its anticancer effects remains elusive. The aim of this study was to determine whether melatonin inhibits lung metastasis in gastric cancer. MAIN METHODS: A lung metastasis model of gastric cancer was established in nude mice injected with human gastric adenocarcinoma MGC80-3 cells. Mice were divided into control, IL-1ß-treated, melatonin-treated, and IL-1ß plus melatonin-treated groups and analyzed for the formation of lung metastatic nodules by flow cytometry and hematoxylin and eosin staining. The mRNA expression of epithelial-mesenchymal transition (EMT) markers was assessed by RT-qPCR. The activities of matrix metalloproteinase (MMP)-2 and MMP-9 were determined by gelatin zymography and their protein expression by western blotting and immunohistochemistry. The levels of NF-κB p65 and phosphorylated (p)-p65 were detected by immunohistochemistry. KEY FINDINGS: The number of lung metastases in the IL-1ß plus melatonin group was significantly lower and the sizes of nodules were smaller than those in the IL-1ß group. Furthermore, melatonin reversed changes in the expression of EMT markers induced by IL-1ß by increasing mRNA levels of ß-catenin and E-cadherin and decreasing those of fibronectin, vimentin, and Snail compared to IL-1ß. Treatment with IL-1ß upregulated the expression and activities of MMP-2 and MMP-9 and expression of NF-κB p65 and phospho-p65 (p-p65), but melatonin alleviated these effects. SIGNIFICANCE: Melatonin inhibited IL-1ß-induced lung metastasis of gastric cancer through downregulation of MMP-2, MMP-9, and NF-κB p65 expression and activities. These findings provide a basis for potential use of melatonin as a supplementary therapy for patients with advanced gastric cancer.

Exosomes derived from acute myeloid leukemia cells promote chemoresistance by enhancing glycolysis-mediated vascular remodeling.

Acute myeloid leukemia (AML) is the most common type of leukemia in adults. AML cells secrete angiogenic factors to remodel vasculature and acquire chemoresistance; however, antiangiogenic drugs are often ineffective in AML treatment. Cancer cell-derived exosomes can induce angiogenesis, but their role in vascular remodeling during AML is unclear. Here, we found that exosomes secreted by AML cells promoted proliferation and migration and tube-forming activity of human umbilical vein endothelial cells (HUVECs), whereas HUVECs conferred chemoresistance to AML cells. AML cell-derived exosomes contained vascular endothelial growth factor (VEGF) and VEGF receptor (VEGFR) messenger RNA and induced VEGFR expression in HUVECs. Furthermore, they enhanced glycolysis, which correlated with HUVEC proliferation, tube formation, and resistance to apoptosis. Thus, AML cells secrete VEGF/VEGFR-containing exosomes that induce glycolysis in HUVECs leading to vascular remodeling and acquisition of chemoresistance. These findings may contribute to the development of novel therapeutic strategies targeting exosomes in AML.