Study On Anti-tumor Activity And Ameliorating Cancer-associated Cachexia Effect Of Cerebrosides Derived From Acaudina Molpadioides And Asterias Amurensis

Cerebrosides are one of the important bioactive lipids of glycosphingolipids and existin cytomembrane, with a variety of biological activities such as anti-virus, anti-microbial,anti-inflammatory and immunomodulatory. The cerebrosides which mainly exist in bodywall are the primary bioactive compositions of sea cucumber and starfish. Nowadays, thereare few studies on the anti-tumor activity of cerebrosides derived from sea cucumber andstarfish and still remain in vitro experiments level. In this study, the cerebrosides wereseparately extracted from sea cucumber Acaudina Molpadioides and starfish Asteriasamurensis, the anti-tumor activity and mechanism of which in vitro and vivo weredetermined. Moreover, the improving roles of the AMC and AAC on cancer-associatedcachexia (CAC) were assessed, as well as the mechanism was systematically undertaken atthe level of cytokines and molecular biology. The relationship between structures andactivities was compared. The main findings in this thesis are as follows:Firstly, MTT assay is used to determine the anti-proliferation ability of AMC and itslong-chain bases (LCB). The results suggest that AMC and LCB can inhibit theproliferation activity of HepG2, S180,95D, Caco-2and HGC-27cells and exhibit adose-dependent inhibitory effect on the viability of different cells，which indicate that bothAMC and LCB inhibit cell proliferation effectively and LCB shows a stronger effect thanAMC. To confirm the anti-tumor effects of AMC and LCB in vivo, we establish S180ascites tumor mice model and the animals in each group are administered intragastrically(i.g.) or intraperitoneal injection (i.p.) of test drugs. These findings show that LCB increasethe life span of the S180ascites tumor mice significantly by i.g. or i.p., and the results bear out that LCB has a high anti-tumor activity in vivo. But AMC markedly exhibitsanti-tumor activity in S180ascites tumor mice only treated by i.g., and the anti-tumoractivity of AMC treated by i.g. is similar to LCB. From these results, it is possible that theLCB produced by digestion and absorption of AMC in the intestine are responsible for thesuppression of tumorigenesis in vivo. The results infer that the LCB is the anti-tumor effectof active site of AMC.A further study is conducted to compare the relationship between structure, anti-tumoractivities and the mechanisms of cerebrosides. The investigation of the anti-tumor effectsand mechanisms of AMC and AAC is conducted in vitro and using two tumor mice model.The results turn out that AMC seemed to be less effective than AMC in vitro but morepotent in vivo. It may attribute to the structural differences in their fatty acid groups, LCBand the cerebrosides hydrolyzed and absorbed by the intestine are metabolized to activesite. The results explain that both AMC and AAC exhibit an inhibitory effect on cellproliferation through induction of apoptosis and inhibit the growth of S180tumor andascites fluid. Furthermore, the ascites tumor cells viability ratio in AMC and AAC are alsosuppressed. The life span of AMC and AAC administrated groups increased significantly.It is suggested that both AMC and AAC exhibits a potential anti-tumor activity both invitro and in vivo via regulating the immune function, promoting the antioxidant level andinducing apoptosis through mitochondrial apoptotic pathway.CAC is a multifactorial wasting syndrome most common in patients with cancer thatis characterized by the uncontrolled loss of adipose and muscle mass. CAC affects theefficacy and tolerability of therapy, the patient’s quality of life and decreases survival inpatients with cancer. In this study, we have examined and compared the improving roles ofthe AMC and AAC on CAC in animals using a cachexia model established withintraperitoneal injection of S180cells in mice. The results reveal that both AMC and AACresist the loss of body weight and maintain the white adipose tissue (WAT) andgastrocnemius muscle mass. AMC and AAC can attenuate CAC by reduction the release ofthe cytokines in serum levels, such as tumor necrosis factor-alpha (TNF-α), interleukin-1 (IL-1) and IL-6. AMC and AAC can resist increased WAT lipolysis by decreasing theexpression of adipose triglyceride lipase (ATGL), hormone-sensitive lipase (HSL) andzinc-α2-glycoprotein (ZAG). AMC and AAC also play an important role in lipogenesisthrough promoting the adipocyte differentiation, increasing the transport and uptake ofglucose and fatty acids into adipocyte, and up-regulation the SREBP-1c and then activatingthe lipogenic pathway by stimulating the expression of genes encoding lipogenic enzymes.Moreover, the lipid utilisation genes in WAT such as UCP2and PGC-1α mRNA expressionwere inhibited by AMC and AAC.The phosphatidylcholine (PC) extracted from starfish Asterias amurensis enrich theeicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and have prominentanti-tumor activity. Therefore, we eventually mix the AAC and Asterias amurensisphosphatidylcholine (AAP) and evaluate the anti-tumor activity of the mixture of AAC andAAP (AAM). In view of the results, the AAM show a stronger effect than AAM or AAPtreatment only.In conclusion, this is the first time to systematically study and compare the beneficialeffect and mechnism of AMC and AAC on anti-tumor activity in vitro and vivo andameliorating CAC. Furthermore, it is the first time to find that the mixture of cerebrosidesand phosphatidylcholine extracted from starfish Asterias amurensis has more prominentanti-tumor activity than AAM or AAP treatment only. The findings in this thesis offercredible theoretical and reasonable scientific reference for the deep exploitation of seacucumber and utilization starfish waste.