Lysophosphatidylcholine acyltransferase 1 promotes epithelial-mesenchymal transition of hepatocellular carcinoma via the Wnt/ß-catenin signaling pathway.

INTRODUCTION AND OBJECTIVES: Hepatocellular carcinoma (HCC) is one of the most malignant digestive tumors, and its insidious onset and rapid progression are the main reasons for the difficulty in effective treatment. Lysophosphatidylcholine acyltransferase 1 (LPCAT1) is a key enzyme that regulates phospholipid metabolism of the cell membrane. However, the mechanism by which LPCAT1 regulates HCC metastasis remains unknown. This study aimed to explore its biological function and potential mechanisms concerning migration and invasion in HCC. MATERIALS AND METHODS: LPCAT1 expression in HCC tissues and its association with clinical outcomes were investigated by western blotting and bioinformatic methods, respectively. The role of LPCAT1 in migration and invasion was assessed via Transwell assays. The expression pattern of epithelial-mesenchymal transition (EMT) markers was quantified by western blotting. The biological behaviors of LPCAT1 in vivo were evaluated using xenograft tumor models and caudal vein metastatic models. Signaling pathways related to LPCAT1 were predicted using gene set enrichment analysis (GSEA) and further confirmed by western blotting. RESULTS: LPCAT1 expression was significantly upregulated in HCC tissues and indicated a poor prognosis of HCC patients. Several EMT-related markers were found to be regulated by LPCAT1. HCC cells overexpressing LPCAT1 exhibited remarkably high migration and invasion capacities, upregulated expression of mesenchymal markers and reduced E-cadherin expression. In vivo, LPCAT1 promoted HCC pulmonary metastasis. Furthermore, the Wnt/ß-catenin signaling pathway was confirmed to be activated by LPCAT1. CONCLUSIONS: LPCAT1 could serve as a promising biomarker of HCC and as a novel therapeutic target for the treatment of metastatic HCC.

3' Truncation of the GPD1 promoter in Saccharomyces cerevisiae for improved ethanol yield and productivity.

Glycerol is a major by-product in bioethanol fermentation by the yeast Saccharomyces cerevisiae, and decreasing glycerol formation for increased ethanol yield has been a major research effort in the bioethanol field. A new strategy has been used in the present study for reduced glycerol formation and improved ethanol fermentation performance by finely modulating the expression of GPD1 in the KAM15 strain (fps1Δ pPGK1-GLT1 gpd2Δ). The GPD1 promoter was serially truncated from the 3' end by 20 bp to result in a different expression strength of GPD1. The two engineered promoters carrying 60- and 80-bp truncations exhibited reduced promoter strength but unaffected osmostress response. These two promoters were integrated into the KAM15 strain, generating strains LE34U and LE35U, respectively. The transcription levels of LE34U and LE35U were 37.77 to 45.12% and 21.34 to 24.15% of that of KAM15U, respectively, depending on osmotic stress imposed by various glucose concentrations. In very high gravity (VHG) fermentation, the levels of glycerol for LE34U and LE35U were reduced by 15.81% and 30.66%, respectively, compared to KAM15U. The yield and final concentration of ethanol for LE35U were 3.46% and 0.33% higher, respectively, than those of KAM15U. However, fermentation rate and ethanol productivity for LE35U were reduced. On the other hand, the ethanol yield and final concentration for LE34U were enhanced by 2.28% and 2.32%, respectively, compared to those of KAM15U. In addition, a 2.31% increase in ethanol productivity was observed for LE34U compared to KAM15U. These results verified the feasibility of our strategy for yeast strain development.

Decreased xylitol formation during xylose fermentation in Saccharomyces cerevisiae due to overexpression of water-forming NADH oxidase.

The recombinant xylose-fermenting Saccharomyces cerevisiae strain harboring xylose reductase (XR) and xylitol dehydrogenase (XDH) from Scheffersomyces stipitis requires NADPH and NAD(+), creates cofactor imbalance, and causes xylitol accumulation during growth on d-xylose. To solve this problem, noxE, encoding a water-forming NADH oxidase from Lactococcus lactis driven by the PGK1 promoter, was introduced into the xylose-utilizing yeast strain KAM-3X. A cofactor microcycle was set up between the utilization of NAD(+) by XDH and the formation of NAD(+) by water-forming NADH oxidase. Overexpression of noxE significantly decreased xylitol formation and increased final ethanol production during xylose fermentation. Under xylose fermentation conditions with an initial d-xylose concentration of 50 g/liter, the xylitol yields for of KAM-3X(pPGK1-noxE) and control strain KAM-3X were 0.058 g/g xylose and 0.191 g/g, respectively, which showed a 69.63% decrease owing to noxE overexpression; the ethanol yields were 0.294 g/g for KAM-3X(pPGK1-noxE) and 0.211 g/g for the control strain KAM-3X, which indicated a 39.33% increase due to noxE overexpression. At the same time, the glycerol yield also was reduced by 53.85% on account of the decrease in the NADH pool caused by overexpression of noxE.

[Application of transanal ileus tube followed by laparoscopic surgery for malignant colorectal obstruction].

OBJECTIVE: To evaluate the safety and efficacy of transanal drainage tube followed by laparoscopic surgery in management of malignant colorectal obstruction. METHODS: From March 2007 to October 2010, 37 patients with colorectal cancer manifesting acute complete mechanical obstruction were treated by ileus tube drainage. After irrigation and drainage ranging from 4 to 10 days, the radical operations and anastomosis were performed by laparoscopy. RESULTS: The drainage tubes were successfully implanted in 34 patients. The decompression time of patients was (5.8 ± 1.6) d, ranging from 4 to 10 d. The abdominal pain and bloating symptoms were faded away after (3.8 ± 1.3) d (1 to 7 d) drainage. And comparing to that of patients when admission, abdominal circumference significantly reduced from (92 ± 7) cm to (84 ± 6) cm (P = 0.013) before surgery. Thirty-one cases were performed radical resection and anastomosis by laparoscopy after decompression. Postoperative recovery was smooth, and there was no serious complication. CONCLUSIONS: Laparoscopic surgery followed decompression by transanal ileus tube is effective and safe for acute lower colorectal obstruction. Emergency surgery may be converted to limit surgery by this method. After appropriate bowel preparation, laparoscopic radical surgery and anastomosis is feasible.

Improving ethanol fermentation performance of Saccharomyces cerevisiae in very high-gravity fermentation through chemical mutagenesis and meiotic recombination.

Genome shuffling is an efficient way to improve complex phenotypes under the control of multiple genes. For the improvement of strain's performance in very high-gravity (VHG) fermentation, we developed a new method of genome shuffling. A diploid ste2/ste2 strain was subjected to EMS (ethyl methanesulfonate) mutagenesis followed by meiotic recombination-mediated genome shuffling. The resulting haploid progenies were intrapopulation sterile and therefore haploid recombinant cells with improved phenotypes were directly selected under selection condition. In VHG fermentation, strain WS1D and WS5D obtained by this approach exhibited remarkably enhanced tolerance to ethanol and osmolarity, increased metabolic rate, and 15.12% and 15.59% increased ethanol yield compared to the starting strain W303D, respectively. These results verified the feasibility of the strain improvement strategy and suggested that it is a powerful and high throughput method for development of Saccharomyces cerevisiae strains with desired phenotypes that is complex and cannot be addressed with rational approaches.