Downregulation of GLYAT Facilitates Tumor Growth and Metastasis and Poor Clinical Outcomes Through the PI3K/AKT/Snail Pathway in Human Breast Cancer

Abstract

BackgroundThe Glycine N-acyltransferase (GLYAT) gene encodes a protein that catalyzes the transfer of acyl groups from acyl CoA to glycine, resulting in acyl glycine and coenzyme A. Aberrant GLYAT expression is associated with several malignant tumors, but its clinical importance in human breast cancer (BC), has yet to be fully addressed. This study aims to evaluate the clinical function of GLYAT in BC patients.MethodsGLYAT expression was determined by immune blot and immunohistochemistry in three BC cell lines and primary cancer tissues. The MDA-MB 231 cell line was used for GLYAT gene knockdown experiments while the MCF7 cell line for overexpression experiments. Colony formation experiments, soft agar experiments, and transwell assays were utilized for further inspection of cell proliferation and migration capabilities. Immunofluorescence and western blot were used to detect markers of the epithelial-mesenchymal transition (EMT) and changes in the PI3K/AKT/Snail pathway. The role of GLYAT in tumor growth and metastasis was also assessed in nude mice in vivo. Also, a correlation analysis was performed between clinicopathological features and GLYAT expression in BC patients.ResultsGLYAT was decreased in human BC tissues and cell lines. Functional analysis showed that knockdown of GLYAT augmented BC cell proliferation in vitro and in vivo. However, this phenomenon was reversed when GLYAT was overexpressed in the transfected cells. Moreover, downregulation of GLYAT promoted the migratory properties of BC cells, likely through the activation of PI3K/AKT/Snail signaling, which subsequently induced the EMT. IHC analysis indicated that GLYAT was decreased in human BC tissues and lower GLYAT expression was correlated with histological grade, tumor TNM stage, Ki-67 status, and poorer survival in BC patients. Furthermore, lower GLYAT expression seemed as an independent risk factor related to poor prognosis in BC patients based on Cox regression analyses.ConclusionOur findings demonstrate that downregulation of GLYAT expression in human breast cancer is correlated with EMT via the PI3K/AKT/Snail pathway and is also associated with histological grade, tumor TNM stage, Ki-67 status, and poor survival in breast cancer patients.

Frequent sequence variants of human glycine N-acyltransferase (GLYAT) and inborn errors of metabolism

“…Nonetheless, recent studies ascertained that GLYAT and GLYATL1 possess functions beyond detoxification. Human GLYAT was downregulated in human breast cancer tissue [150], whereas GLYATL1 expression level was reduced in hepatocellular carcinoma [62]. The same finding was described for the human GLYAT eight years before [107].…”

“…Human GLYAT was decreased in human breast cancer tissues and a GLYAT knockdown augmented the cancer cell proliferation in vivo and in vitro [150]. However, that phenomenon was not confirmed when GLYAT was overexpressed in transfected cells.…”

“…The human GLYAT was downregulated in hepatocellular carcinoma cells [107]. A more recent study described the association of GLYAT to breast cancer [150]. GLYAT was identified as antioncogene associated with malignant clinicopathological features that enhances breast cancer metastasis in mice.…”

“…From another point of view, GLYAT is involved in hepatocellular carcinoma as is it strongly downregulated in cancerous rat cells shown by Western blot and RT-qPCR study [107] Thus, a relation of GLYAT to human liver cancer or other liver diseases is impressively confirmed. In more recent studies, the roles of human GLYAT and GLYATL1 were investigated in the context of cancer [62,150].…”

Gamma-ray Irradiation of Rodent Diets Alters the Urinary Metabolome in Rats with Chemically Induced Mammary Cancer

“…Higher levels of N-acylglycine in the gID fed urine samples may also reflect increased activity of glycine N-acyltransferase. Reduced levels of glycine N-acyltransferase have been reported in human breast cancer metastasis and progression [ 42 , 43 ]. Animals fed with gID diet showed higher levels of glycine betain, compared to non-gID group.…”