Association Between OxLDL And Esophageal Cancer And The Possible Mechanism

ObjectivesThe purpose of the study is to prove whether oxidation low density lipoprotein (oxLDL)have association with the risk of the carcinogenic process of esophageal squamous cell carcinoma(ESCC)and to discuss the potential mechanism in case there is an association.Content and Methodsâ… . A study of the relationship between oxLDL and the risk of the carcinogenic process of ESCC1. The subjects consist of 33 controls with normal esophageal squamous epithelial cells, 37 cases with esophageal basal cell hyperplasia (BCH), 47 cases with esophageal squamous cell dysplasia (ESCD), and 43 cases with ESCC; all are diagnosed by endoscopic biopsy via pathology in the screening program in Feicheng County.2. Test the level of components of serum lipid Serum total cholesterol (TC), triglycerides (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL) levels were determined by enzymatic techniques; Serum albumin was determination by bromocresol green (BCG); oxLDL, oxLDL antibody (oxLDL-Ab), immunoglobulin G, and M subtypes autoantibody to oxLDL (oxLDL-lgG and oxLDL-lgM) were measured by enzyme linked immunosorbent assay (ELISA).3. Statistical analysis: The univariate and multinomial logistic regression method were carried out by SPSS15.0, P<0.05 think difference have statistical significance.â…¡. The influence of oxLDL on person esophageal cancer cell line Eca109 and possible mechanism1. To detect the influence of oxLDL and antibodies on Eca109 cell proliferation; The interaction effect of oxLDL combined ADM to suppress Eca109 cell roliferation.2. The apoptosis index of Eca109 induced by oxLDL: To observe the morphology changes of apoptosis cells under optical microscope after a Giemsa's staining of the cells; the flow cytometer is used to detect cell apoptosis rates and cell cycle changes for each group.3. The expression levels of Bax, Bcl-2,Caspase-3 mRNA genes and proteins of Eca109 cells apoptosis induced by oxLDL alone or combined with ADM are assayed by RT-PCR and Western-blotting.Resultsâ… . A study on the association of oxLDL with different stages of carcinogenic process of ESCC1. Unvariate analysis showed that age, the levels of serum albumin, TC, HDL, LDL, oxLDL, oxLDL-Ab, oxLDL-lgG and oxLDL-lgM were significantly different among the four groups with the development of EC, however, no significant differences were observed for the other factors.2. With the development progression of esophageal cancer, the serum oxLDL, oxLDL-Ab, oxLDL-lgG levels tends to decreased, however the serum oxLDL-lgM level increased gradually. Among the four groups the serum levels of oxLDL and oxLDL-lgM still have statistic significant differences; but no significant differences were observed for oxLDL-ab and oxLDL-lgG after adjustment for the confounding variables age, TC, LDL, HDL and serum albumin.3. The serum levels of oxLDL, oxLDL-Ab, oxLDL-lgG were obviously negative associated with the development progression of ESCC, however positively correlation with oxLDL-lgM (P<0.01).4. After adjustment for age, TC, LDL and HDL and serum albumin, there was a protective effect to ESCC with the increase of oxLDL(OR=0.94, 95%CI:0.89-0.99); while oxLDL-lgM showed increasing in the risk of ESCD and ESCC, OR were1.11(95%CI:1.01-1.23)and 1.18(95%CI:1.06-1.31)for them, respectively.â…¡. The influence of oxLDL on person esophageal cancer cell line Eca109 and possible mechanism1. Influence on cell proliferation1.1 Along with the increasing of oxLDL concentration or reactive time, the cell viability reduced in a dose- response and time- effect model.1.2 Neithor oxLDL-Ab nor oxLD-R-Ab had influence on Eca109 cell activity. There have no influence of oxLDL-Ab on the viability inhibition stimulated by oxLDL, However, oxLDL-R-Ab can reduced the viability inhibition rate caused by oxLDL ( from 27.73% to 7.31%, P<0.05).1.3 With the increasing of ADM concentration or reactive time, the cell viability and reduced in a dose-response and time- effect model.1.4 oxLDL can enlarge the cell viability inhibition caused by ADM (inhibition rates from 28.35% to 43.97%, P<0.05), which implies that the two factors may have a synergistic effect.2. Influence on cell apoptosis1.1 oxLDL and ADM make Ecal09 cell to appear morpholog changes, appearing the apoptotic body even nuclear destruction.1.2 Cell apoptosis rate increased with the oxLDL concentration or reaction time increasing, and with apparent dose-response and time- effect dependent relationship (P<0.01).1.3 oxLDL-Ab has no significant influence on the cell apoptosis rate caused by oxLDL, while oxLDL-R-Ab partial inhibition the increase of the cell apoptosis rate caused by oxLDL (apoptosis rate from 15.11% reduced to 12.58%, P<0.05).1.4 oxLDL can strengthen the role of ADM inducing cell apoptosis, from 11.27% of ADM group to19.79%,P<0.05; the lord effect and their interactions significantly, two factors existing synergistic effect.3. The change of cell cycle3.1 Along with the increase of oxLDL concentration,the S phase increase gradually, but G0/G1 and G₂/M period proportion are gradual decline.3.2 oxLDL-Ab and oxLDL-R-Ab almost cannot chang the cell cycle distribution, oxLDL-Ab without influence on the change of the cell cycle lead by oxLDL, while oxLDL-R-Ab lead to S phase block function caused by oxLDL reduce(form 29.86% drop to 24.97%, P<0.05).3.3 The percentages of the S phase of cell cycle for the oxLDL group and ADM group, comparing with the control group (22.03%), rose to 29.86% and 62.59%, respectively. The cell prolifelation was blocked at the S phase. Forethermore, oxLDL and ADM combined make G₂/M phase proportion increased to75.66% and the cell prolifelation was blocked at the G₂/M phase.4. The expression of cell apoptosis-related genes and proteinsoxLDL could significantly reduce the expression level of Bcl-2 mRNA and protein, while increased the expression level of Bax, Caspase-3 mRNA and protein, at one time whith a decreasing Bcl-2/Bax ratio. oxLDL combined ADM group Bcl-2 mRNA and protein expression level significantly lower compare with separate group, Bax, Caspase-3 mRNA and proteins also increased significantly.Conclusion1. With the development progession of ESCC range from normal to the BCH, ESCD, and invasive ESCC, oxLDL and oxLDL-Ab level declined, and negatively related with the development process of ESCC; while oxLDL-lgM show upward trend,was positively associated with the development process of ESCC .2. oxLDL has obvious cytotoxicity, whith can inhibit the proliferation of esophageal cancer cell, induce apoptosis, making the cell cycle appear S period block. oxLDL can significantly reduce Bcl-2 while increased Bax and Caspase-3 genes and proteins expression level.3. oxLDL antibody composition of oxLDL-Ab and oxLDL- R -Ab separately without influence on esophageal cancer cell proliferation; however oxLDL-R-Ab can reduce partly cytotoxicity of oxLDL.4. oxLDL and ADM combined existing synergistic effect on cell toxicity .