Breast cancer is a kind of common female cancers. Increasing evidence has exhibited that lncRNAs exert a crucial role in breast cancer. So far, the mechanism of lncRNAs in breast cancer is still not well established. In our current study, we focused on the biological role of lncRNA Nuclear Enriched Abundant Transcript 1 (NEAT1) in breast cancer. We observed that NEAT1 levels were significantly increased in human breast cancer cells including MCF-7, MDA-MB-453, MDA-MB-231, and SKBR3 cells compared to normal mammary epithelial cells MCF-10A while miR-448 was decreased. We found that downregulation of NEAT1 was able to inhibit the growth of breast cancer cells and miR-448 mimic exerted the similar function. Bioinformatics analysis and dual luciferase reporter assays confirmed the negative correlation between NEAT1 and miR-448 in vitro. In addition, ZEB1 was predicted as a novel mRNA target of miR-448. Overexpression of NEAT1 can induce breast cancer cell growth, migration, and invasion by inhibiting miR-448 and upregulating ZEB1. It was demonstrated that NEAT1 can increase ZEB1 levels while miR-448 mimic can repress ZEB1. It was speculated in our study that NEAT1 can serve as a competing endogenous lncRNA (ceRNA) to modulate ZEB1 by sponging miR-448 in breast cancer. To conclude, we uncovered that NEAT1 participated in breast cancer progression by regulating miR-448 and ZEB1. NEAT1 can be provided as a vital biomarker in breast cancer diagnosis and treatment therapy.
RNA-binding proteins (RBPs) play essential roles in RNA metabolism, regulating RNA splicing, transport, surveillance, decay and translation. The aberrant expression of RBPs leads to gene expression alteration and frequently causes various diseases, such as cancer. In this study, we are the first to provide evidence that hMex-3A, a RBP that belongs to the human Mex-3 family with two K-homology RNA-binding domains, is involved in the regulation of tumorigenesis. We show that the silencing of hMex-3A by small interference RNA effectively inhibits cell proliferation in SNU-16 and AGS gastric cancer cells. Flow cytometry analysis confirmed this effect on SNU-16 cell growth and indicated that hMex-3A may function in the G1/M phase. Notably, hMex-3A knockdown also reduced the colony formation ability of SNU-16 and AGS cells in soft agar, implying that hMex-3A is required for cell transformation. Furthermore, the hMex-3A knockdown markedly affected the migratory ability of BCG-823 cells by transwell chamber and wound healing assays. Clinical relevance analysis using 22 paired gastric cancer specimens by quantitative real-time PCR showed that hMex-3A was significantly upregulated (63.6%) in cancer tissues compared with matched adjacent non-cancerous tissues. Taken together, these results suggest that hMex-3A functions as an oncogene candidate in the development and metastasis of gastric cancer; thus it may serve as a potential target for the therapy of tumors.
To evaluate the protective effects of α-lipoic acid on the kidneys of Goto-Kakisaki (GK) diabetic rats, ten GK diabetic rats were randomly divided into a diabetic control group and a lipoic acid-treated diabetic group with α-lipoic acid 35 mg·Kg−1 intraperitoneal injections. Four healthy Wistar rats served as normal controls. Malonaldehyde (MDA), ascorbic acid (vitamin C), vitamin E, glutathione (GSH) and superoxide dismutase (SOD) levels in renal homogenate, and urine protein excretion were measured. The expression of mRNA for NF-κB, NADPH oxidase subunits p22phox and p47phox in renal tissue was examined by realtime PCR. Pathological changes in renal tissue were evaluated by light and electron microscopy. There were significant increases in urine protein excretion, MDA levels and the expression of mRNA of NF-κB, p22phox and p47phox, and significant decreases in GSH, SOD, vitamin C and vitamin E levels in the diabetic control group compared with the normal control group. Pathological changes of renal tissue were more progressive in the diabetic control group than in the normal control group. All the parameters above were improved in the α-lipoic acid-treated diabetic group. Oxidative stress is increased in the kidney of type 2 diabetic GK rats. It is associated with the progression of diabetic nephropathy. α-lipoic acid can protect renal function in diabetic rats via its antioxidant activity.
Recent studies demonstrated the beneficial role of atorvastatin in reducing the risk of cardiovascular morbidity and mortality in patients with diabetes mellitus and/or metabolic syndrome. To investigate the mechanisms underlying the anti-atheroscleroic action of atorvastatin, we examined the expression of the receptor for advanced glycation end products (RAGE) and its downstream target gene, monocyte chemoattractant protein-1 (MCP-1) using real time RT-PCR. In in vitro studies, exposure to high glucose or AGE induced oxidative stress and activation of the AGE/RAGE system in human umbilical vein endothelial cells. Treatment of the cells with atorvastatin significantly released the oxidative stress by restoring the levels of glutathione and inhibited the RAGE up-regulation. In diabetic Goto Kakisaki (GK) rats fed with a high fat diet for 12 weeks, RAGE and MCP-1 were upregulated in the aortas, and there was a significant correlation between RAGE and MCP-1 mRNA abundance (r=0.482, P=0.031). Treatment with atorvastatin (20 mg/kg qd) significantly downregulated the expression of RAGE and MCP-1. These data thus demonstrate a novel “pleiotropic” activity of atorvastatin in reducing the risk of cardiovascular diseases by targeting RAGE expression.
Background Emerging evidence suggests that metabolic alterations are a hallmark of cancer cells and contribute to tumor initiation and development. Cancer cells primarily utilize aerobic glycolysis (the Warburg effect) to produce energy and support anabolic growth. The type Iγ phosphatidylinositol phosphate kinase (PIPKIγ) is profoundly implicated in tumorigenesis, however, little is known about its role in reprogrammed energy metabolism. Methods Loss- and gain-of-function studies were applied to determine the oncogenic roles of PIPKIγ in colorectal cancer. Transcriptome analysis, real-time qPCR, immunohistochemical staining, Western blotting, and metabolic analysis were carried out to uncover the cellular mechanism of PIPKIγ. Findings In this study, we showed that PIPKIγ was frequently upregulated in colorectal cancer and predicted a poor prognosis. Genetic silencing of pan-PIPKIγ suppressed cell proliferation and aerobic glycolysis of colorectal cancer. In contrast, the opposite effects were observed by overexpression of PIPKIγ_i2. Importantly, PIPKIγ-induced prolific effect was largely glycolysis-dependent. Mechanistically, PIPKIγ facilitated activation of PI3K/Akt/mTOR signaling pathways to upregulate c-Myc and HIF1α levels, which regulate expression of glycolytic enzymes to enhance glycolysis. Moreover, pharmacological inhibition by PIPKIγ activity with the specific inhibitor UNC3230 significantly inhibited colorectal cancer glycolysis and tumor growth. Interpretation Our findings reveal a new regulatory role of PIPKIγ in Warburg effect and provide a key contributor in colorectal cancer metabolism with potential therapeutic potentials. Fund National Key Research and Development Program of China, Outstanding Clinical Discipline Project of Shanghai Pudong, Natural Science Foundation of China, and Science and Technology Commission of Shanghai Municipality.
Colorectal cancer (CRC) remains the third most commonly diagnosed cancer, ranking second among the most common causes of cancer-related mortality. Immune checkpoint therapy has recently been shown to have great potential. However, only some patients respond to immune checkpoint blockade, indicating the unmet need for determining the underlying mechanism of colorectal cancer immunosuppression. In this study, we analyzed The Cancer Genome Atlas (TCGA) datasets and found that high expression of PIPKIγ positively correlated with tumor-associated macrophage infiltration. Further loss-of-function studies revealed that silencing PIPKIγ greatly reduced CCL2 expression at both the mRNA and protein levels, leading to weak chemotaxis of cancer cells to macrophages. Mechanistically, PIPKIγ facilitated PI3K-Akt-mTOR signaling pathway activation to increase STAT3 phosphorylation levels, thus triggering CCL2 transcription to enhance tumor-associated macrophage recruitment. These findings identify the PIPKIγ signaling pathway as a new actor in colorectal cancer immunosuppression and a potential therapeutic target for this common cancer.
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