TGF­ß1­induced epithelial­mesenchymal transition increases fatty acid oxidation and OXPHOS activity via the p­AMPK pathway in breast cancer cells.

Breast cancer is the most common malignancy in women, and metastasis is the leading cause of death in breast cancer patients. Previous studies have shown that epithelial­mesenchymal transition (EMT) is involved in the metastasis of breast cancer, but the metabolic reprogramming and regulation mechanisms involved in the EMT process are still unclear. In the present study, we successfully constructed an EMT cell model induced by transforming growth factor ß1 (TGF­ß1) treatment of MCF­7 cells at different times. The results showed that cell adhesion decreased, cell invasion increased and ATP levels increased in EMT MCF­7 cells treated with TGF­ß1. Furthermore, the expression of fatty acid synthase (FASN) was decreased, and the expression of key fatty acid ß­oxidation enzymes (CPT1 and CD36) was elevated in treated cells compared to control cells. These results showed that the fatty acid oxidation pathway was enhanced. In addition, the expression of NADH:ubiquinone oxidoreductase subunit B8 (NDUFB8), mitochondrial transcription factor A (TFAM) and cytochrome c oxidase subunit I (COXI) increased, and the mitochondrial DNA copy number and ROS levels were also significantly increased during TGF­ß1­induced EMT. These results indicated that mitochondrial oxidative phosphorylation (OXPHOS) activity was enhanced during EMT. In addition, we observed that the expression of p­AMPK was increased and ACC (Acetyl­CoA Carboxylase) was decreased during TGF­ß1­induced EMT in MCF­7 cells. Immunohistochemical analysis of clinical samples revealed high expression of FASN in epithelial cells that had high expression of E­cadherin, while high expression of CPT­1 was observed in mesenchymal cells that had high expression of vimentin. Results of the current study showed a metabolic transition in TGF­ß1­induced EMT in MCF­7 cells. This transition may regulate fatty acid oxidation and OXPHOS activity in EMT MCF­7 cells through the p­AMPK pathway. These data suggest that a metabolic transition that suppresses lipogenesis and favors energy production is an essential component of TGF­ß1­induced EMT and metastasis in breast cancer. This study thus provides a new strategy for identifying new therapeutic targets for breast cancer.

High expression of the TEFM gene predicts poor prognosis in hepatocellular carcinoma.

BACKGROUND: Mitochondrial transcription elongation factor (TEFM) is an essential molecule that regulates the replication-transcription switch of mitochondrial DNA. TEFM modulates both transcription elongation and RNA processing in mitochondria. The purpose of the present study was to determine the association of TEFM with tumor progression and prognosis in hepatocellular carcinoma (HCC) patients. METHODS: The different protein expression level of TEFM among HCC cell lines was detected by Western blotting. The gene expression profiling interactive analysis (GEPIA) was used to dynamically analyze the mRNA expression of TEFM gene in different stages of HCC. The protein and mRNA expression levels of TEFM were detected by immunohistochemistry, Western blotting and qRT-PCR. The mRNA-SeqV2 expression of TEFM and clinical information of HCC patients were downloaded from the TCGA database by using R3.6.3 software. Next, the relationships between the expression level of TEFM and clinicopathological characteristics and the prognostic value of TEFM were analyzed. A Cox regression model was used for multivariate analysis of the factors that affected the prognosis of HCC. Finally, the association between the expression levels of TEFM and other mitochondrial regulatory genes and HCC biomarker genes was analyzed by GEPIA. RESULTS: TEFM is upregulated in HCC cell lines compared to noncancerous liver cell line. TEFM protein and mRNA expression levels in HCC tissues were significantly upregulated compared with those in noncancerous liver tissues. In addition, the mRNA expression level of TEFM was significantly correlated with sex, serum AFP level, and vascular invasion (P<0.05). Further analysis showed that high expression level of TEFM was unfavorable in terms of the prognosis of patients with HCC. Cox multivariate regression analysis showed that patient age, vascular invasion, and TEFM expression were independent factors affecting the prognosis of HCC patients (P<0.05). The expression level of the TEFM gene was significantly positively correlated with the expression of multiple mitochondrial regulatory genes and biomarker genes of HCC (P<0.01, R>0). CONCLUSIONS: Our findings reveal that TEFM may play an important role in the progression of HCC. More importantly, the elevated expression of TEFM may potentially predict poor overall survival (OS) and disease-free survival (DFS) in patients with HCC.

Expression of MTERF3 gene in breast carcinoma and the relationship with clinicopathological characteristics.

BACKGROUND: Mitochondrial transcription termination factor 3 (MTERF3) is a negative regulator of mitochondrial transcription. It is a modular factor involves in mitochondrial ribosome biogenesis and protein synthesis. However, the association between MTERF3 and breast cancers remains largely unknown. The aim of this study was to investigate the expression of MTERF3 in breast carcinoma and to analyze its clinicopathological significance, and to examine the potential prognostic value of MTERF3 in breast cancer. METHODS: The protein expression levels of MTERF3 in MCF7 (Luminal A), BT-474 (Luminal B), SKBR3 (HER2 overexpression), MDA-MB-468 (Basal like) and MCF10A cell lines were detected by Western blotting. Immunohistochemistry (IHC), Western blotting, and semiquantitative RT-PCR were performed to analyze the protein and mRNA expression levels of MTERF3 in 58 breast cancer tissues and 58 noncancerous breast tissues. The MTERF3 expression data and clinical information from breast cancer patients were downloaded from the TCGA dataset by using the R3.6.1 software. Then the relationship between the expression level of MTERF3 and clinicopathological characteristics and the prognostic value was analyzed. A Cox regression model was performed for the multivariate analysis of the factors that affected the prognosis of breast cancer. The association between the expression levels of MTERF3 and other mitochondrial regulatory genes was analyzed with GEPIA. RESULTS: MTERF3 is upregulated in breast cancer cell lines compared to noncancerous breast cell line. The IHC results showed that the MTERF3 protein was located in the cytoplasm, and the rate of positive expression in breast cancer tissue was significantly upregulated compared with the adjacent normal tissue. The mRNA and protein expression levels of MTERF3 in breast cancer tissues were significantly higher than that in breast tissues. Moreover, the expression of MTERF3 was significantly correlated with ER status, PR status, breast cancer molecular typing, cancer type, histological diagnosis and primary site (P<0.05). Further analysis showed MTERF3 expression was not related to prognosis. Multivariate Cox regression analysis showed that age, metastasis status and tumor type were independent prognostic factors for breast cancer patients. The expression levels of MTERF3 were positively correlated with the TFAM, TFB1M, TFB2M, MTERF1, TEFM and MFN1 genes but negatively correlated with the MTERF4 and PINK1 genes. In addition, the expression levels of MTERF3 were not correlated with the MTERF2 gene. CONCLUSIONS: MTERF3 was significantly upregulated in breast cancer cells and tissues compared with noncancerous cells and tissues. Moreover, the expression level of MTERF3 was correlated with ER status, PR status, breast cancer molecular typing, cancer type, histological diagnosis and primary site. These findings suggested that the upregulation of MTERF3 may be used as a diagnostic and therapeutic target in breast carcinoma.