RNF6 promotes colorectal cancer invasion and migration via the Wnt/β-catenin pathway by inhibiting GSK3β activity.

The purpose of this study was to explore the molecular mechanism underlying the interaction between ring finger protein 6 (RNF6) and glycogen synthase kinase 3β (GSK3β) in colorectal cancer (CRC). In this study, cell models of overexpressed or silenced RNF6 were established by liposome transfection, and IM-12 was used as the inhibitor of GSK3β. Real-time quantitative PCR and western blots were used to detect the expression of RNF6, p-GSK3β, GSK3β, and β-catenin, and MTT assays were used to quantify cell proliferation. The tumorigenicity of cells was observed by plate clonal formation assay; the invasiveness of cells was examined in Transwell Boyden chambers, and the migratory capacity of cells was tested by scratch wound assays. The rat CRC model was induced by AOM/DSS, in which we verified activity in the Wnt/β-catenin pathway by examining GSK3β phosphorylation. RNF6 was upregulated in CRC samples and cell lines. Silencing or overexpressing RNF6 in colorectal cancer cells inhibited or promoted, respectively, the proliferation, tumorigenicity, invasion and migration of CRC cells, as well as expression of p-GSK3β, GSK3β and β-catenin. IM-12 reversed the Wnt/β-catenin-activated state change induced by RNF6 silencing and the inhibition of cell proliferation, tumorigenicity, invasion and migration. The same results were observed in vivo in the rat CRC model. Overexpression of RNF6 in CRC increased the GSK3β phosphorylation level, which led to activation of the Wnt/β-catenin pathway and promoted the invasion and migration of CRC cells, suggesting that RNF6 may be a novel target for the treatment of CRC.

Li Q ，Wang G ，Tao J ，Chen W ... -  《-》

MiR-452 promotes an aggressive colorectal cancer phenotype by regulating a Wnt/β-catenin positive feedback loop.

Li T ，Jian X ，He H ，Lai Q ，Li X ，Deng D ，Liu T ，Zhu J ，Jiao H ，Ye Y ，Wang S ，Yang M ，Zheng L ，Zhou W ，Ding Y ... -  《JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH》

In vivo and in vitro effects of microRNA-27a on proliferation, migration and invasion of breast cancer cells through targeting of SFRP1 gene via Wnt/β-catenin signaling pathway.

Kong LY ，Xue M ，Zhang QC ，Su CF ... -  《Oncotarget》

B-cell translocation gene 3 overexpression inhibits proliferation and invasion of colorectal cancer SW480 cells via Wnt/β-catenin signaling pathway.

Mao D ，Qiao L ，Lu H ，Feng Y ... -  《NEOPLASMA》

Hypoxia-induced lncRNA STEAP3-AS1 activates Wnt/β-catenin signaling to promote colorectal cancer progression by preventing m(6)A-mediated degradation of STEAP3 mRNA.

Hypoxia, a typical hallmark of solid tumors, exhibits an essential role in the progression of colorectal cancer (CRC), in which the dysregulation of long non-coding RNAs (lncRNAs) is frequently observed. However, the underlying mechanisms are not clearly defined. The TCGA database was analyzed to identify differential lncRNA expression involved in hypoxia-induced CRC progression. qRT-PCR was conducted to validate the upregulation of lncRNA STEAP3-AS1 in CRC cell lines and tumor-bearing mouse and zebrafish models under hypoxia. ChIP-qRT-PCR was used to detect the transcriptional activation of STEAP3-AS1 mediated by HIF-1α. RNA-seq, fluorescent in situ hybridization, RNA pulldown, RNA immunoprecipitation, co-immunoprecipitation, immunofluorescence and immunoblot experiments were used to ascertain the involved mechanisms. Functional assays were performed in both in vitro and in vivo models to investigate the regulatory role of STEAP3-AS1/STEAP3/Wnt/β-catenin axis in CRC proliferation and metastasis. Here, we identified a hypoxia-induced antisense lncRNA STEAP3-AS1 that was highly expressed in clinical CRC tissues and positively correlated with poor prognosis of CRC patients. Upregulation of lncRNA STEAP3-AS1, which was induced by HIF-1α-mediated transcriptional activation, facilitated the proliferation and metastasis of CRC cells both in vitro and in vivo. Mechanistically, STEAP3-AS1 interacted competitively with the YTH domain-containing family protein 2 (YTHDF2), a N6-methyladenosine (m6A) reader, leading to the disassociation of YTHDF2 with STEAP3 mRNA. This effect protected STEAP3 mRNA from m6A-mediated degradation, enabling the high expression of STEAP3 protein and subsequent production of cellular ferrous iron (Fe2+). Increased Fe2+ levels elevated Ser 9 phosphorylation of glycogen synthase kinase 3 beta (GSK3β) and inhibited its kinase activity, thus releasing β-catenin for nuclear translocation and subsequent activation of Wnt signaling to support CRC progression. Taken together, our study highlights the mechanisms of lncRNA STEAP3-AS1 in facilitating CRC progression involving the STEAP3-AS1/STEAP3/Wnt/β-catenin axis, which may provide novel diagnostic biomarkers or therapeutic targets to benefit CRC treatment. Hypoxia-induced HIF-1α transcriptionally upregulates the expression of lncRNA STEAP3-AS1, which interacts competitively with YTHDF2, thus upregulating mRNA stability of STEAP3 and consequent STEAP3 protein expression. The enhanced STEAP3 expression results in production of cellular ferrous iron (Fe2+), which induces the Ser 9 phosphorylation and inactivation of GSK3β, releasing β-catenin for nuclear translocation and contributing to subsequent activation of Wnt signaling to promote CRC progression.

Zhou L ，Jiang J ，Huang Z ，Jin P ，Peng L ，Luo M ，Zhang Z ，Chen Y ，Xie N ，Gao W ，Nice EC ，Li JQ ，Chen HN ，Huang C ... -  《Molecular Cancer》