Downregulation of Long Noncoding RNA HOTAIR andEZH2Induces Apoptosis and Inhibits Proliferation, Invasion, and Migration of Human Breast Cancer Cells

2018 ◽  
Vol 33 (6) ◽  
pp. 241-251 ◽  
Author(s):  
Lu Han ◽  
Hai-Chao Zhang ◽  
Li Li ◽  
Cai-Xia Li ◽  
Xu Di ◽  
...  
Cancers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 628
Author(s):  
Jilei Zhang ◽  
Rong Lu ◽  
Yongguo Zhang ◽  
Żaneta Matuszek ◽  
Wen Zhang ◽  
...  

Background: Transfer RNA (tRNA) queuosine (Q)-modifications occur specifically in 4 cellular tRNAs at the wobble anticodon position. tRNA Q-modification in human cells depends on the gut microbiome because the microbiome product queuine is required for its installation by the enzyme Q tRNA ribosyltransferase catalytic subunit 1 (QTRT1) encoded in the human genome. Queuine is a micronutrient from diet and microbiome. Although tRNA Q-modification has been studied for a long time regarding its properties in decoding and tRNA fragment generation, how QTRT1 affects tumorigenesis and the microbiome is still poorly understood. Results: We generated single clones of QTRT1-knockout breast cancer MCF7 cells using Double Nickase Plasmid. We also established a QTRT1-knockdown breast MDA-MB-231 cell line. The impacts of QTRT1 deletion or reduction on cell proliferation and migration in vitro were evaluated using cell culture, while the regulations on tumor growth in vivo were evaluated using a xenograft BALB/c nude mouse model. We found that QTRT1 deficiency in human breast cancer cells could change the functions of regulation genes, which are critical in cell proliferation, tight junction formation, and migration in human breast cancer cells in vitro and a breast tumor mouse model in vivo. We identified that several core bacteria, such as Lachnospiraceae, Lactobacillus, and Alistipes, were markedly changed in mice post injection with breast cancer cells. The relative abundance of bacteria in tumors induced from wildtype cells was significantly higher than those of QTRT1 deficiency cells. Conclusions: Our results demonstrate that the QTRT1 gene and tRNA Q-modification altered cell proliferation, junctions, and microbiome in tumors and the intestine, thus playing a critical role in breast cancer development.


Author(s):  
Pengwei Lu ◽  
Yuanting Gu ◽  
Lin Li ◽  
Fang Wang ◽  
Xue Yang ◽  
...  

Breast cancer is a serious threat to women’s physical and psychological health. Long noncoding RNA CAMTA1 (lncCAMTA1) was believed to be related with tumor progression, but its role in breast cancer is not clear. The human breast cancer cell line MDA-MB-231 was used to investigate the effect of lncCAMTA1 on cell viability, migration/invasion, and apoptosis. The expression of lncCAMTA1, miR-20b, and VEGF in MDA-MB-231 were measured after corresponding transfections. Binding effects between lncCAMTA1 and miR-20b, miR-20b, and VEGF 3′-UTR were measured. The effects of miR-20b and VEGF on breast cancer cells were also assessed after transfections. The phosphorylation levels of the MAPK/ERK and JAK/STAT3 pathways were determined to assess the effect of VEGF. The results showed that lncCAMTA1 expression promoted cell viability and migration/invasion, while knockdown of lncCAMTA1 promoted cell apoptosis via binding with miR-20b. lncCAMTA1 negatively regulated miR-20b expression. VEGF was a target of miR-20b, leading to the modification of the phosphorylation levels of MAPK, ERK, JAK, STAT1, and STAT3. Our findings suggested that lncCAMTA1 might promote proliferation and mobility of human breast cancer cells via binding with miR-20b. VEGF was a direct target of miR-20b and regulated activation of the MAPK/ERK and JAK/STAT3 signaling pathways. Therefore lncCAMTA1 has potential as a novel cancer diagnostic marker and as a putative novel therapeutic target for breast cancer treatment.


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