Study On Lipidology In The Development Of Cancer

The research work about this dissertation is referred to many research fields, such as analytical chemistry, chemical biology and clinical oncology. Using different technologies in comparative lipidomics and systems biology, we studied the lipid mechanism of hepatocellular carcinoma(HCC) metastasis and PI3K pathway.The main contributions of this dissertation are as follows:1. Totally530lipids and23differential lipids were identified from liver cancer cell lines, and C16:0containing phospholipids were decreased with increasing metastatic ability.2. Using different growth factors to stimulate293cell line, the contents of PIP3compounds in PI3K signaling pathways were changed differently.3. In methodology study, different technologies such as shotgun lipidomics, LC-MS, MRM, GC-MS were found to have distinguish characters on the study of HCC metastatic mechanisms. And PIP3methylation quantitative method was found to be feasible.Hepatocellular carcinoma (HCC) is the third most common cause of cancer related death and occurs highly in China. And high metastasis and recurrence remain the major threats to long-term survival after surgery. Elucidation of molecular mechanism of HCC metastasis and finding out biomarkers for clinical early and specific diagnose, is very important for improving survival time and life quality of HCC patients. In the work of this dissertation, human HCC cell lines with different metastatic potential but similar gene background were studied. With multiple kinds of lipidomics technologies and bio-informatics tools, the mechanism of HCC metastasis was studied. In addition, The phosphoinositide3kinase (PI3K) pathway is a key signal transduction system that links oncogenes and multiple receptor classes to many essential cellular functions, and is perhaps the most commonly activated signalling pathway in human cancer. Therefore, understanding the acted mechanism of PI3K signaling pathways used in cancer treatment has. become the focus of attention. In the work of this dissertation,293cell lines stimulated by different growth factors were studied. With lipidomics technologies, the acted mechanism of PI3K signaling pathways were studied. Totally six parts of this dissertation are discussed as follows:First Part:Background. The improvements in the lipidomic technology and HCC mechanism study field in recent years are summarized in this part. Different lipidomic identification/quantification technologies are compared and discussed about their advantages and limitations. As well, the construction and metastatic characters of the HCC cell lines used in our work are described. In addition, research progress of the lipid signaling molecules in the PI3K signaling pathway are reviewed in this part.Second Part:Comparative lipidomic study on HCC cell lines with different metastatic potential. In this part, we studied the comparative lipidomic profiles of the three metastatic HCC cell lines for the first time. Compared with HEP3B cell line, in the metastasis HCC cells, sulfatide, triglyceride, sphingolipids Cer(d18:1/16:0) and Cer(d18:1/24:0) increased, and Phosphatidylcholine decreased. In addition, phospholipids with C16:0fatty acyl chain decreased, and phospholipids with C18:0fatty acyl chain increased.Third Part:Effects of palmitic acid (C16:0) on HCC metastatic ability. In this part, firstly, MRM and GC-MS technologies were carried out on the differential lipids which were identified in the second part to prove the adverse change in fatty acyl16:0and18:1phospholipids in the high metastasis cell lines. From functional study of the palmitic acid to HCC metastasis, palmitic acid significantly inhibited cell proliferation and invasion of HCC cells. Therefore, phospholipids with C16:0fatty acyl chain maybe inhibited the metastatic ability of HCC cell lines.Fourth Part:The studies of PIP3compounds in293cell lines stimulated with different growth factors. In this part, PIP3methylation and biological mass spectrometry technology were carried out on studies of PIP3compounds in293cell lines stimulated with different growth factors. Totally25PIP3molecular were identified.the differences between three growth factor, EGF, IGF, PDGF regulated the constitution and quantity of PIP3were firstly proved in lipidomic levels, which will provide new clues and evidence for further research of PI3K signaling pathways.