Study On The Correlation Between Serum IGFBP2 Level And Cachexia In Pancreatic Cancer

Background The incidence of malignancies is increasing year by year,whereas advanced patients tend to suffer from cachexia that seriously threatens their quality of life.By international consensus,cancer cachexia is proposed to be “a multifactorial syndrome defined by an ongoing loss of skeletal muscle mass with or without loss of fat mass that cannot be fully reversed by conventional nutritional support and leads to progressive functional impairment”.Cachexia affects 60%-80% of patients with advanced cancer,which is frequently described in patients with pancreatic ductal adenocarcinoma(PDAC)and results in reduced tolerance to cancer therapies,quality of life,and survival.However,precise mechanism of cachexia induction is not fully explained,and a more clinical relevant definition of cachexia was needed in order to design useful clinical trials and improve our understanding of the pathogenic mechanisms.Previous studies indicated that IGFBP2,one of the most abundant circulating IGFBPs,is known to attenuate the biological action of IGF-1,exhibits an average over expression of 4.8-fold change in PDAC and has been studied as a circulating biomarker in lung and liver cancers.However,the precise relationship between IGFBP2 and cachexia in PDAC is not fully explained.As a result,a novel clinical diagnostic criteria of PDAC cachexia,which combines serum IGFBP2 level and skeletal muscle index,is promising to be conducted.Method 1.Analysis of the association between serum IGFBP2 levels and several clinic-pathological parameters in PDAC.Serum IGFBP2 levels were quantified by enzyme-linked immunosorbent assay(ELISA)in a cohort of 98 PDAC patients and 30 healthy people.To further study the involvement of IGFBP2 in PDAC cachexia and progression,we analyzed the correlation between serum IGFBP2 levels and several PDAC clinic-pathological parameters.2.Analysis of the association between serum IGFBP2 levels and muscle wasting.We analyzed the L3 skeletal muscle CT image of PDAC patients,SMI calculated as lumbar total muscle cross-sectional area(cm)2/height(m)2,and association with serum IGFBP2 level.In addition,we analyzed the relationship between serum IGFBP2 levels and prealbumin as well as CRP.3.Analysis of the association between serum IGFBP2 levels and tumor IGFBP2 expression.We got the same result in mouse model of pancreatic cancer,the levels of serum IGFBP2 in Pan02 group is significantly high than control,and appearing the symptom of cachexia.We analyzed 98 cases of pancreatic cancer tissue samples and 15 cases of healthy control by immunohistochemistry.In 98 cases of pancreatic cancer samples,55 samples showed high IGFBP2 expression.4.We establish an IGFBP2 stable overexpression and knock-down cell lines using PLV-IGFBP2 and PLKO-IGFBP2 stable transfection which confirmed by western blot and ELISA.We established the mouse model of pancreatic cancer and measured food intake and body weight every day.Expression of several essential muscle-related signal proteins such as Atrogin-1,Mu RF1,AKT,p-AKT were examined using Western blot and PCR.The results 1.Serum IGFBP2 levels are associated with cachexia.Serum IGFBP2 level in PDAC(415.5 ± 139.4 ng/m L,mean ± standard deviation)is higher than that of healthy control samples(259.1 ± 59.8 ng/m L P<0.001).And the levels of IGFBP2 in cachexia samples(453.5 ± 132.2 ng/m L,mean ± standard deviation)is significantly higher than that of non cachexia.2.Serum IGFBP2 levels are associated with SMI and HU.We can demonstrate high content of serum IGFBP2 is related to muscle consumption and worse prognosis,may be have relationship with several inflammatory factors.3.Serum IGFBP2 levels are associated with tumor IGFBP2 expression.We found that 55 samples of 98 cases with pancreatic cancer showed high IGFBP2 expression.This result suggests that IGFBP2 is highly expressed in pancreatic tumors.Then we analyze the correlation between tumor IGFBP2 expression and serum IGFBP2 level and surprise found their correlation coefficient(Rs)of 0.562,P<0.001.4.Serum IGFBP2 causes muscle wasting through IGF/AKT signaling way.Mice injected Pan02 PLV-IGFBP2 cell are increasing body weight loss and decreasing food intake and significantly aggravating the muscle wasting compare to injected Pan02 PLV-Control,however,these symptoms were alleviated in the PLKO-IGFBP2 group.Results in vivo showed that Pan02 PLV-IGFBP2 cells could obviously increase Atrogin-1,Mu RF1,and decrease p-AKT expression.Conclusions 1.The high level of serum IGFBP2 in PDAC significantly correlates with cachexia.2.The high content of serum IGFBP2 increased muscle wasting and related to worse prognosis.3.Serum IGFBP2 level is consistent with tumor IGFBP2 expression.4.IGFBP2 induced muscle wasting via suppression of IGF/AKT signaling in C57 mouse.As a result,in pancreatic cancer,elevated levels of serum IGFBP2 are associated with the disease and can cause severe muscle wasting.