Ayinde Oluseyi, Wang Zhuo, Griffin Martin
School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, United Kingdom.
Oncotarget. 2017 Mar 21;8(12):20025-20041. doi: 10.18632/oncotarget.15370.
Human colon cancer cell lines (CRCs) RKO, SW480 and SW620 were investigated for TG2 involvement in tumour advancement and aggression. TG2 expression correlated with tumour advancement and expression of markers of epithelial-mesenchymal transition (EMT). The metastatic cell line SW620 showed high TG2 expression compared to the primary tumour cell lines SW480 and RKO and could form tumour spheroids under non- adherent conditions. TG2 manipulation in the CRCs by shRNA or TG2 transduction confirmed the relationship between TG2 and EMT. TGFβ1 expression in CRC cells, and its level in the cell medium and extracellular matrix was increased in primary tumour CRCs overexpressing TG2 and could regulate TG2 expression and EMT by both canonical (RKO) and non-canonical (RKO and SW480) signalling. TGFβ1 regulation was not observed in the metastatic SW620 cell line, but TG2 knockdown or inhibition in SW620 reversed EMT. In SW620, TG2 expression and EMT was associated with increased presence of nuclear β-catenin which could be mediated by association of TG2 with the Wnt signalling co-receptor LRP5. TG2 inhibition/knockdown increased interaction between β-catenin and ubiquitin shown by co-immunoprecipitation, suggesting that TG2 could be important in β-catenin regulation. β-Catenin and TG2 was also upregulated in SW620 spheroid cells enriched with cancer stem cell marker CD44 and TG2 inhibition/knockdown reduced the spheroid forming potential of SW620 cells. Our data suggests that TG2 could hold both prognostic and therapeutic significance in colon cancer.
研究了人结肠癌细胞系（CRC）RKO、SW480和SW620中组织转谷氨酰胺酶2（TG2）在肿瘤进展和侵袭中的作用。TG2表达与肿瘤进展以及上皮-间质转化（EMT）标志物的表达相关。与原发性肿瘤细胞系SW480和RKO相比，转移性细胞系SW620显示出高TG2表达，并且在非贴壁条件下能够形成肿瘤球。通过短发夹RNA（shRNA）或TG2转导对CRC中的TG2进行调控，证实了TG2与EMT之间的关系。在过表达TG2的原发性肿瘤CRC中，CRC细胞中转化生长因子β1（TGFβ1）的表达及其在细胞培养基和细胞外基质中的水平升高，并且可以通过经典信号通路（RKO）和非经典信号通路（RKO和SW480）调节TG2表达和EMT。在转移性SW620细胞系中未观察到TGFβ1调节作用，但在SW620中敲低或抑制TG2可逆转EMT。在SW620中，TG2表达和EMT与核β-连环蛋白的增加有关，这可能是由TG2与Wnt信号共受体低密度脂蛋白受体相关蛋白5（LRP5）的结合介导的。共免疫沉淀显示，TG2抑制/敲低增加了β-连环蛋白与泛素之间的相互作用，表明TG2在β-连环蛋白调节中可能很重要。在富含癌症干细胞标志物CD44的SW620球状体细胞中，β-连环蛋白和TG2也上调，并且TG2抑制/敲低降低了SW620细胞形成球状体的潜力。我们的数据表明，TG2在结肠癌中可能具有预后和治疗意义。
