BCAT1 overexpression is an indicator of poor prognosis in patients with urothelial carcinomas of the upper urinary tract and urinary bladder
HISTOPATHOLOGY
Authors: Chang, I-Wei; Wu, Wen-Jen; Wang, Yu-Hui; Wu, Ting-Feng; Liang, Peir-In; He, Hong-Lin; Yeh, Bi-Wen; Li, Chien-Feng
Abstract
AimsAmino acid biosynthesis is one of the cardinal events of carcinogenesis that has not been investigated in urothelial carcinoma (UC). By data-mining a published transcriptomic database of UCs of urinary bladder (UBUCs) (GSE31684), we identified branched-chain amino acid transaminase 1 (BCAT1) as the most significantly stepwise up-regulated gene during tumour progression among those associated with the amino acid biosynthetic process (GO:0008652). Accordingly, we analysed BCAT1 transcript and protein expression with their clinicopathological significance. Methods and resultsWe used real-time reverse transcription-polymerase chain reaction (RT-PCR) to detect BCAT1 transcript levels in 20 UCs of upper tract (UTUCs) and 20 UBUCs, respectively. Immunohistochemical study was performed to determine BCAT1 protein expression in 340 UTUCs and 295 UBUCs. Higher BCAT1 transcript levels were associated with higher pT status in both groups (P<0.05). BCAT1 protein overexpression was also associated significantly with adverse clinicopathological features, e.g. advanced pT stage, nodal metastasis, high pathological grade, etc. (P<0.05). BCAT1 overexpression predicted worse disease-specific survival and metastasis-free survival in both univariate and multivariate analyses (P0.001). ConclusionBCAT1 overexpression is associated with advanced tumour status, and implies adverse clinical outcomes of UCs, suggesting that its role in tumour progression could serve as a prognostic biomarker and a novel therapeutic target in UC.
BCAT1, a key prognostic predictor of hepatocellular carcinoma, promotes cell proliferation and induces chemoresistance to cisplatin
LIVER INTERNATIONAL
Authors: Zheng, Yi-Hu; Hu, Wei-Jian; Chen, Bi-Cheng; Grahn, Tan-Hooi-Min; Zhao, Yan-Rong; Bao, Hai-Li; Zhu, Ye-Fan; Zhang, Qi-Yu
Abstract
Background & Aims: BCAT1 initiates the catabolism of branched-chain amino acids. Here, we investigated the function of BCAT1 and its transcriptional regulatory mechanism in hepatocellular carcinoma (HCC). Methods: RNASeq was used to evaluate BCAT1 mRNA levels in HCC and normal matched specimens. After the exogenous expression of BCAT1 in BEL-7404 cells and the suppression of endogenous BCAT1 expression with shRNA in HepG2 cells, the cell proliferation, clone-forming ability and cell-cycle changes were measured with MTT assay, colony-forming assay and flow cytometry respectively. A xenograft model was used to investigate the effect of BCAT1 on cancer growth in vivo. Chromatin immunoprecipitation and luciferase reporter technologies were used to confirm the transcriptional regulation of the BCAT1 gene by MYC. The expression of the BCAT1 and MYC proteins in 122 HCC tissues was determined with an immunohistochemical analysis. Results: BCAT1 mRNA was clearly increased in HCC tissues and hepatomas. The ectopic expression of BCAT1 in BEL-7404 cells enhanced their proliferation, clone formation, tumourigenic properties, S-G2/M phase transition and chemoresistance to cisplatin. The suppression of BCAT1 expression in HepG2 cells significantly inhibited their proliferation, clone formation, and S-G2/M phase transition and caused their chemosensitization to cisplatin. MYC affected the transcriptional regulation of BCAT1. Clinical data showed that BCAT1 expression correlated with a significantly poorer prognosis. Conclusion: BCAT1 plays a pathogenic role in HCC by causing cell proliferation and chemoresistance. The MYC transcription factor is involved in regulating the transcriptional activity of BCAT1. BCAT1 expression has prognostic significance for the survival of patients with HCC.