SRGN-TGF beta 2 regulatory loop confers invasion and metastasis in triple-negative breast cancer
ONCOGENESIS
Authors: Zhang, Z.; Deng, Y.; Zheng, G.; Jia, X.; Xiong, Y.; Luo, K.; Qiu, Q.; Qiu, Ni; Yin, J.; Lu, M.; Liu, H.; Gu, Y.; He, Z.
Abstract
Patients with triple-negative breast cancers (TNBC) are at a high risk for a recurrent or metastatic disease, and the molecular mechanisms associated with this risk are unclear. Proteoglycan serglycin (SRGN) proteins are involved in tumor metastasis, but their role in TNBC has not yet been elucidated. This study investigates the SRGN gene expression and how it regulates TGF beta 2 and the downstream signaling of TGF beta 2 in TNBC cells and tissues. Our results show that SRGN mRNA and protein expression levels were significantly higher in TNBC cell lines and tumor tissues than that in non-TNBC cells and tissues. We inhibited SRGN expression and protein secretion using shRNA and we observed this inhibited the invasive motility of TNBC cancer cells in vitro and metastasis of TNBC cancer cells in vivo. SRGN protein treatment increased the expression and secretion of transforming growth factor-beta 2 (TGF beta 2) by activating CD44/CREB1 signaling and promoted epithelial-to-mesenchymal transition in TNBC cells. Moreover, TGF beta 2 treatment increased the mRNA and protein expression of the SRGN gene by activating Smad3 to target the SRGN relative promoter domain in TNBC cells. Our findings demonstrate that SRGN interacts with TGF beta 2 which regulates TNBC metastasis via the autocrine and paracrine routes. SRGN could serve as a potential target for development of agents or therapeutics for the TNBC.
SRGN, a new identified shear-stress-responsive gene in endothelial cells
MOLECULAR AND CELLULAR BIOCHEMISTRY
Authors: Ma, Qinfeng; Gu, Wei; Li, Tianhan; Zhang, Kun; Cui, Yuliang; Qu, Kai; Wang, Nan; Humphry, Rose; Durkan, Colm; Qiu, Juhui; Wang, Guixue
Abstract
Endothelial cells (ECs) play an important role in the pathogenesis of cardiovascular disease, especially atherosclerosis (AS). The abnormal wall shear stress (WSS) which directly contacts with ECs is the key stimulating factor leading to AS. However, the underlying mechanism of ECs responding to WSS is still incompletely understood. This study aims to explore the novel mechano-sensitive genes and its potential mechanism in response to WSS in ECs by employing bioinformatics methods based on previously available high-throughput data from zebrafish embryos, both before and after blood flow formation. Six common differentially expressed genes (DEGs) (SRGN, SLC12A3, SLC25A4, PVALB1, ITGAE.2, zgc:198419) were selected out from two high-throughput datasets (GSE126617 and GSE20707) in the GEO database. Among them,SRGNwas chosen for further verification through the in vitro shear stress loading experiments with human umbilical vein endothelial cells (HUVECs) and the in vivo partial ligation of carotid artery in mice. Our data indicated that low shear stress (LSS) could enhance the expression of SRGN via thePKA/CREB-dependent signaling pathway. The proportion of Ki67(+)cells and the concentration of nitric oxide (NO) were high in SRGN high expression cells, suggesting thatSRGNmay be involved in the proliferation of HUVECs. Furthermore, in the partial ligation of the carotid artery mice model, we observed that the expression of SRGN was significantly increased in atherosclerotic plaques induced by abnormal shear stress. Taken together, this study demonstrated thatSRGNis a key gene in the response of ECs to WSS and could be involved in AS.