ABSTRACT
[This retracts the article DOI: 10.1016/j.omtn.2019.09.034.].
ABSTRACT
Gastric cancer (GC) is one of the leading causes of cancer-related deaths worldwide. Accumulating evidence reveals the significance of long non-coding RNAs (lncRNAs) in various cancers. The current study aimed to evaluate the role of GATA6 antisense RNA 1 (GATA6-AS1) in the epithelial-mesenchymal transition (EMT) and lymph node metastasis (LNM) in GC. GC-related microarray datasets were initially retrieved from the GEO with differentially expressed lncRNAs screened, followed by evaluation of the regulatory relationship between Frizzled 4 (FZD4) and GATA6-AS1. The detailed regulatory mechanism by which GATA6-AS1 influences the Wnt/ß-catenin signaling pathway and GC cell biological behaviors was investigated by treating SGC7901 cells with overexpressed GATA6-AS1, specific antisense oligonucleotide against GATA6-AS1, and lithium chloride (LiCl; activator of the Wnt/ß-catenin signaling pathway). Finally, xenograft nude mice were used to assay tumor growth and LNM in vivo. GATA6-AS1 was poorly expressed, but FZD4 was highly expressed in GC tissues and cells. Elevated GATA6-AS1 reduced FZD4 expression by recruiting enhancer of zeste homolog 2 (EZH2) and trimethylation at lysine 27 of histone H3 (H3K27me3) to the FZD4 promoter region via the inactivated Wnt/ß-catenin signaling pathway, whereby cell invasion, migration, and proliferation, tumor growth, and LNM in nude mice were reduced. Taken together, overexpressed GATA6-AS1 downregulated the expression of FZD4 to inactivate the Wnt/ß-catenin signaling pathway, which ultimately inhibited GC progression.
ABSTRACT
BACKGROUND: Matrine is one of the major alkaloids extracted from Sophora flavescens and has been used clinically for breast cancer with notable therapeutic efficacy in China. However, the mechanisms are still largely unknown. METHODS: Cell viability was analyzed by MTT assay. After MCF-7 cells were treated with matrine for 48h, apoptosis was detected by flow cytometry, TUNEL assay and transmission electron microscopy, and the cell cycle distribution was also analyzed by flow cytometry. Further, the expression of PTEN, pAkt, Akt, pBad, Bad, p21(/WAF1/CIP1), and p27(/KIP1) was determined by Western blot. Changes of miR-21 level were quantified by real-time RT-PCR. After miR-21 was transfected in MCF-7 cells, PTEN protein level was measured by Western blot. RESULTS: Matrine inhibited MCF-7 cell growth in a concentration-and time-dependent manner, by inducing apoptosis and cell cycle arrest at G(1)/S phase. Matrine up-regulated PTEN by downregulating miR-21 which in turn dephosphorylated Akt, resulting in accumulation of Bad, p21(/WAF1/CIP1) and p27(/KIP1). CONCLUSION: Our study unraveled, for the first time, the ability of matrine to suppress breast cancer growth and elucidated the miR-21/PTEN/Akt pathway as a signaling mechanism for the anti-cancer action of matrine. Our findings also reinforce the notion that miRNAs can act as mediators of the therapeutic efficacy of natural medicines.
