Optimizing 5-aza-2 '-deoxycytidine treatment to enhance the development of porcine cloned embryos by inhibiting apoptosis and improving DNA methylation reprogramming
RESEARCH IN VETERINARY SCIENCE
Authors: Qu, Jiadan; Wang, Xiangyu; Jiang, Yujia; Lv, Xiaofei; Song, Xuexiong; He, Hongbin; Huan, Yanjun
Abstract
Apoptosis and incomplete DNA methylation reprogramming in cloned embryos reduce cloning efficiency. 5-aza-2'-deoxycytidine (5-aza-dC) is proven to regulate apoptosis and DNA methylation reprogramming, however, the treatment method and potential role of 5-aza-dC during cloned embryo development are still not well studied. This study displayed that treating donor cells with 5-aza-dC (AN group) significantly reduced the blastocyst rate, while treating cloned embryos (NA group) or both donor cells and cloned embryos (ANA group) significantly promoted the blastocyst formation, and the ANA group was the best treatment of 5-aza-dC to enhance the development of cloned embryos. Then, compared with the NT group, the ANA group showed the significantly enhanced nuclear remodeling. The apoptotic cell numbers and rates of blastocysts were significantly reduced, and the expression levels of significantly upregulated anti-apoptosis gene Bcl2l1 and downregulated proapoptosis genes Box, P53 and Caspase3 were observed in the ANA group. Further study demonstrated that the transcription levels of DNA methylation reprogramming genes Dnmt1, Dnmt3a, Tell and Tet3 were significantly upregulated, and, significant genomic DNA remethylation, DNA demethylation of pluripotency gene Oct4, and DNA remethylation of tissue specific gene Thy1 were observed at the blastocyst stage in the ANA group. Embryo development related genes including Igf2, H19, Oct4, Nanog, Sox2, Eif1a, Cdx2 and ATP1b1 were significantly upregulated, and Thy1 and Co15a2 were remarkably silenced at the 4-cell and blastocyst stages in the ANA group. In conclusion, the best 5-aza-dC treatment enhanced the development of cloned embryos by inhibiting apoptosis and improving DNA methylation reprogramming.
Circulating tumor DNA as an emerging liquid biopsy biomarker for early diagnosis and therapeutic monitoring in hepatocellular carcinoma
INTERNATIONAL JOURNAL OF BIOLOGICAL SCIENCES
Authors: Wu, Xiaolin; Li, Jiahui; Gassa, Asmae; Buchner, Denise; Alakus, Hakan; Dong, Qiongzhu; Ren, Ning; Liu, Ming; Odenthal, Margarete; Stippel, Dirk; Bruns, Christiane; Zhao, Yue; Wahba, Roger
Abstract
As one of the most common malignant tumors worldwide, hepatocellular carcinoma (HCC) is known for its poor prognosis due to diagnosis only in advanced stages. Nearly 50% of the patients with the first diagnosis of HCC die within a year. Currently, the advancements in the integration of omics information have begun to transform the clinical management of cancer patients. Molecular profiling for HCC patients is in general obtained from resected tumor materials or biopsies. However, the resected tumor tissue is limited and can only be obtained through surgery, so that dynamic monitoring of patients cannot be performed. Compared to invasive procedures, circulating tumor DNA (ctDNA) has been proposed as an alternative source to perform molecular profiling of tumor DNA in cancer patients. The detection of abnormal forms of circulating cell-free DNA (cfDNA) that originate from cancer cells (ctDNA) provides a novel tool for cancer detection and disease monitoring. This may also be an opportunity to optimize the early diagnosis of HCC. In this review, we summarized the updated methods, materials, storage of sampling, detection techniques for ctDNA and the comparison of the applications among different biomarkers in HCC patients. In particular, we analyzed ctDNA studies dealing with copy number variations, gene integrity, mutations (RAS, TERT, CTNNB1, TP53 and so on), DNA methylation alterations (DBX2, THY1, TGR5 and so on) for the potential utility of ctDNA in the diagnosis and management of HCC. The biological functions and correlated signaling pathways of ctDNA associated genes (including MAPK/RAS pathway, p53 signaling pathway and Wnt-beta catenin pathway) are also discussed and highlighted. Thus, exploration of ctDNA/cfDNA as potential biomarkers may provide a great opportunity in future liquid biopsy applications for HCC.