LncRNA DANCR promotes macrophage lipid accumulation through modulation of membrane cholesterol transporters.

The progression of atherosclerosis (AS), the pathological foundation of coronary artery disease (CAD), is featured by massive lipid deposition in the vessel wall. LncRNAs are implicated in lipid disorder and AS, whereas the specific role of lncRNA DANCR in atherogenesis remains unknown. Here, we demonstrated that DANCR promotes macrophage lipid accumulation by regulating the expression of membrane cholesterol transport proteins. qPCR showed that compared to control groups, CAD patients and atherosclerotic mice had higher DANCR levels. Treating human THP-1 macrophages and mouse RAW264.7 macrophages with ox-LDL significantly upregulated the expression levels of DANCR. Oil Red O staining showed that the silence of DANCR robustly reduced, while overexpression of DANCR significantly increased the numbers and size of lipid droplets in ox-LDL-treated THP-1 macrophages. In contrast, the opposite phenomena were observed in DANCR overexpressing cells. The expression of ABCA1, ABCG1, SR-BI, and NBD-cholesterol efflux was increased obviously by DANCR inhibition and decreased by DANCR overexpression, respectively. Furthermore, transfection with DANCR siRNA induced a robust decrease in the levels of CD36, SR-A, and Dil-ox-LDL uptake, while DANCR overexpression amplified the expression of CD36, SR-A and the uptake of Dil-ox-LDL in lipid-laden macrophages. Lastly, we found that the effects of DANCR on macrophage lipid accumulation and the expression of membrane cholesterol transport proteins were not likely related to miR-33a. The present study unraveled the adverse role of DANCR in foam cell formation and its relationship with cholesterol transport proteins. However, the competing endogenous RNA network underlying these phenomena warrants further exploration.

Effect of miR-33a-3p on Chemoresistance of Colorectal Cancer by Regulating EphA2 / 华中科技大学学报(医学版)

@#Objective Toinvestigatetheregulatoryeffect of microRNA-33a-3p(miR-33a-3p)on chemoresistances of colorectal cancer(CRC). Methods Theexpression of miR-33a-3pin CRC parentalcells(HCT8)and drug-resistantcelllines(HCT8/5-Fu and HCT8/DDP) was detected by quantitative real-time PCR. The miR-33a-3p mimics and negative control mimics were constructed andtransfectedinto CRCdrug-resistantcells. Cell proliferation,apoptosis,cellcycledistributionandchemosensitivity weretested. Thetarget genes of miR-33a-3p were predicted via bioinformatics methods,andtheeffect of overexpressed miR- 33a-3p onthe downstreamtarget gene EphA2 was detected by quantitative real-time PCR and Western blot. Results The expression of miR-33a-3pin HCT8/5-Fu and HCT8/DDP cells was significantlylowerthanthat ofthe parentalcells(P <0.01) .Compared with the negative control group,overexpression of miR-33a-3p could suppress HCT8/5-Fu and HCT8/DDP cells proliferation and promotecell apoptosis,and block cells cyclein G2/M phase as well as enhancecell chemosensitivity(P <0.05) .Bioinformatics predictionresults showedthat EphA2 might bea downstreamtarget gene of miR-33a-3p,andits expression was significantlyreducedin HCT8/5-Fu and HCT8/DDP cells transfected with miR-33a-3p mimics. Conclusion The miR-33a-3p mayreversethechemoresistance of CRC byregulatingthe expressionlevel of downstreamtarget gene EphA2.

Hsa_circ_0002162 has a critical role in malignant progression of tongue squamous cell carcinoma through targeting miR-33a-5p

The aim of this study was to explore the effect of hsa_circ_0002162 on regulating cell proliferation, apoptosis, and invasion, and investigate its potential target microRNA (miRNA) in tongue squamous cell carcinoma (TSCC). Hsa_circ_0002162 expression was detected in human TSCC cell lines and human oral keratinocytes (HOK) cell line. Cell proliferation, apoptosis, invasion, and candidate target miRNA expressions were detected in hsa_circ_0002162 knockdown-treated CAL-27 cells and hsa_circ_0002162 overexpression-treated SCC-9 cells. In the rescue experiment, miR-33a-5p knockdown plasmid was transfected into hsa_circ_0002162 knockdown-treated CAL-27 cells, while miR-33a-5p overexpression plasmid was transfected into hsa_circ_0002162 overexpression-treated SCC-9 cells. Subsequently, cell proliferation, apoptosis, and invasion were detected, and then luciferase reporter assay was performed. Hsa_circ_0002162 expression was increased in human TSCC cell lines SCC-9, CAL-27, HSC-4, and SCC-25 compared with HOK. In CAL-27 cells, hsa_circ_0002162 knockdown inhibited cell proliferation and invasion and promoted apoptosis. In SCC-9 cells, hsa_circ_0002162 overexpression enhanced cell proliferation and invasion and suppressed apoptosis. Furthermore, a negative regulation of hsa_circ_0002162 on miR-33a-5p (but not miR-302b-5p and miR-545-5p) was observed. In the rescue experiment, miR-33a-5p knockdown increased cell proliferation and invasion, and decreased apoptosis in hsa_circ_0002162 knockdown-treated CAL-27 cells, whereas miR-33a-5p overexpression decreased cell proliferation and invasion, but increased apoptosis in hsa_circ_0002162 overexpression-treated SCC-9 cells. The luciferase reporter assay showed the direct binding of hsa_circ_0002162 to miR-33a-5p. In conclusion, hsa_circ_0002162 had an important role in malignant progression of TSCC through targeting miR-33a-5p.

Down regulation of miR-33a is involved in gemcitabine chemoresistance in human pancreatic cancer / 中国癌症杂志

Background and purpose:Pancreatic cancer is one of the most deadly human malignant neoplasms. Resistance to chemotherapeutic drugs is a major reason responsible for poor prognosis in the treatment of pancreatic cancer patients. MicroRNA (miRNA, miR) is a family of small non-coding RNA molecules, dysregulated miRNA is associated with various tumor biological function. miR-33a has been widely reported as a metabolism-related miRNA, while its relationship with drug resistance has little understand. This study was focused on the effect of miR-33a on gemcitabine chemoresistance in pancreatic cancer to bring the novel theoretical basis to chemotherapy for pancreatic cancer.Methods:In situ hybridization and Real-time PCR were used to analyze the miR-33a expressions in pancreatic cancer tissue sample and cell lines, respectively. Cell counting kit 8 (CCK-8) assay was used to calculate the IC50 value of different pancreatic cancer cells.Results:miR-33a was down-regulated in pancreatic cancer tissue and cell lines compared with para-cancerous tissues and normal HEK293T cells. Moreover, miR-33a over expression not only could enhance the chemosensitivity to gemcitabine in pancreatic cancer cells, but also rescue the gemcitabine resistance in pancreatic cancer cells.Conclusion:Down regulation of miR-33a in pancreatic cancer decreases the chemosensitivity to gemcitabine, resulting in development of acquired gemcitabine chemoresistance. It provides the theoretical basis to develop a new molecular targeted drug to combine with chemotherapy for pancreatic cancer.

MiR-33a suppresses breast cancer cell proliferation and metastasis by targeting ADAM9 and ROS1

MicroRNAs (miRNAs) are small noncoding RNAs that have a pivotal role in the post-transcriptional regulation of gene expression by sequence-specifically targeting multiple mRNAs. Although miR-33a was recently reported to play an important role in lipid homeostasis, atherosclerosis, and hepatic fibrosis, the functions of miR-33a in tumor progression and metastasis are largely unknown. Here, we found that downregulated miR-33a in breast cancer tissues correlates with lymph node metastasis. MiR-33a expression is significantly lower in the highly metastatic breast cancer cell lines than the noncancerous breast epithelial cells and non-metastatic breast cancer cells. Moreover, the overexpression of miR-33a in metastatic breast cancer cells remarkably decreases cell proliferation and invasion in vitro and significantly inhibits tumor growth and lung metastasis in vivo, whereas its knockdown in non-metastatic breast cancer cells significantly enhances cell proliferation and invasion in vitro and promotes tumor growth and lung metastasis in vivo. Combining bioinformatics prediction and biochemical analyses, we showed that ADAM9 and ROS1 are direct downstream targets of miR-33a. These findings identified miR-33a as a negative regulator of breast cancer cell proliferation and metastasis.