Nuclear Magnetic Resonance-based Metabonomic Study Of Serums From Patients With Different Stages Of Pancreatic Cancer And Rats With Pancreatic Intraepithelial Neoplasia And Pancreatic Adenocarcinoma

Objectives: The objective was to investigate the serum metabonomic profiles of different stages of pancreatic cancer and the serum metabonomic alterations from pancreatic intraepithelial neoplasia(Pan IN)to pancreatic ductal adenocarcinoma(PDAC)and to find potential serum biomarkers for early detection of pancreatic cancer.Methods: Part 1.Serum samples from patients with different stages pancreatic cancers(PCa group)and healthy volunteers(control group)were analyzed by 1H NMR spectroscopy.Patients with pancreatic cancer were classified into 2 groups,including group A(stage ?A+?B)and group B(stage ?+?).Multivariate statistical analyses including principal component analysis(PCA)and(orthogonal)partial least squares discriminant analysis((O)PLS-DA)were performed to identify the characteristic metabolites.Part 2.7,12-dimethylbenz(a)anthracene(DMBA)was implanted into the pancreas of SD rats to induce Pan IN and PDAC,which were confirmed by pathologic examination.The serum samples from the control group,Pan IN group and PDAC group were analyzed by 1H NMR spectroscopy and multivariate statistical analyses were performed to identify the characteristic metabolites.Results: Part 1.Serum samples from 23 patients with pancreatic cancer(including 12 cases of group A and 11 cases of group B)and 16 healthy volunteers were measured.The serum metabonomic profile of PCa group is different from that of control group and 12 characteristic metabolites were identified.Elevated levels of 3-hydroxybuyarate, citrate,formate,glutamate,isoleucine,methionine and phenylalanine and decreased levels of 3-methylhistidine,alanine,glutamine,LDL and VLDL were found in PCa group.Twenty metabolites in serum were found significantly different in the pairwise comparisons among the control group,group A and group B.Comparing with group A,higher levels of 3-methylhistidine,alanine,citrate,creatine,isoleucine,lactate,leucine,lysine,methionine,phenylalanine,threonine and valine,and lower levels of LDL and VLDL were showed in group B.Part 2.SD rat models of Pan IN and PDAC induced by DMBA were successfully established based on pathologic confirmation.Serum samples from Pan IN group(n=10),PDAC group(n=20)and the control group(n=10)were measured.Thirty-seven metabolites in serum were found significantly different in the pairwise comparisons.Elevated levels of glucose,and decreased levels of 3-hydroxybutyrate and lactate,and some amino acids including glutamate,glutamine,leucine,isoleucine and phenylalanine,were demonstrated in PDAC group.Higher levels of ketone bodies including 3-hydroxybutyrate,acetoacetate,and acetone,some amino acids including asparagine,glutamate,threonine,and phenylalanine,glycoprotein and lipoproteins including N-acetylglycoprotein,LDL and VLDL,deoxyguanosine and cytidine were observed in Pan IN group.Conclusions: NMR based metabonomic profiling technology can distinguish the difference of serum metabonomic profile between patients with pancreatic cancers and healthy controls and it can aslo distinguish the difference between pancreatic cancers with different stages.The metabonomic profile of SD rats is similar to that of human.NMR based metabonomic technology can identify the serum metabonomic changes between the control group and Pan IN group or PDAC group,and it aslo identify the serum metabonomic changes from Pan IN to PDAC.Understanding the metabonomic differences between different stages and metabonomic changes from Pan IN to PDAC will be helpful to study the development and progression of pancreatic cancer.NMR based metabonomic technology may be a promising approach for the early detection of pancreatic cancer.