| Background and ObjectiveThe incidence of endometrial carcinoma has been rising in recent years. TheMetabolic syndrome, characterized by obesity, hypertension, diabetes mellitus, anddyslipidemia, is closely related with endometrial carcinoma.And the central part ofmetabolic syndrome is insulin resistance.IGFBPs is an important member of theInsulin-like growth factor system(IGFs), including IGFBP1-6which has strongbinding ability with IGFs,and the newly found IGFBP7-15,also called insulin likegrowth factor binding protein-related protein(IGFBP-rP), which has strong bindingability with insulin. lGFBP-rP1is the research focus.Compared with IGFBP1-6,thebinding ability with IGF1and IGF2of lGFBP-rP1is weaker5and20-25times,butstronger500times with insulin.After it combines with IGFBP-rP1,insulin hasdecreased or even no normal physiological effects,leading to decreased sensitivity toinsulin in human body, and participating in malignant cancer development such ascolorectal cancer and breast cancer. Hyperinsulinemia and low IGFBP-rP1level ishigh risk factors for endometrial cancer. However, the role of lGFBP-rP1inendometrial cancer is still unclear. Our research aims at the effect of lGFBP-rP1inendometrial cancer. Plasmid pEX-2–IGFBP-rP1was transfected into endometrial cancer cell line HEC-1A mediated by liposome, the influence of upregulatinglGFBP-rP1on cell proliferantion, apoptosis and cell cycle of HEC-1A was detected,to discover the specific role of lGFBP-rP1in endometrial cancer.Methods1. Cell transfection: Plasmid pEX-2–IGFBP-rP1was transfected into HEC-1Acell mediated by liposome. Cells were divided into3groups: cells transfecting withPlasmid pEX-2–IGFBP-rP1;cells transfecting with plasmid pEX-2–Empty;cellsadded only the reagent of transfection. Cells were observed in fluorescencemicroscope.2.Quantitative RT-PCR method was used to detect the IGFBP-rP1mRNAexpression in each group．3.Western blotting was used to determine the expression of IGFBP-rP1proteinin HEC-1A cells in each group4. Methyl thiazolyl tetrazolium (MTT) was used to detect the cell proliferation24h、48h、72h after transfection in vitro,respctvely.5.Flow cytometry was used to determine cell apoptosis rate and cell cycledistribution, AnnexinV-APC/PI double staining for cell apoptosis rate and PI singlestaining for cell cycle distribution.6. Statistical analysis: Average values were expressed as mean±standarddeviation (SD). Repeated measures analysis of variance was used to measure cellinhibition rate.One-way ANOVA analysis test was used to measure mean differencesof mRNA,protein, cell apoptosis rate and cell cycle distribution. LSD test was usedfor pairwise comparison. Bilateral α=0.05was considered as test standards.Results1.The IGFBP-rP1mRNA expression1evels in pEX-2–IGFBP-rP1transfectedgroup were2.699±0.293，and protein level was1.126±0.074, which were obviouslyelevated compared with pEX-2–Empty tranfected group（1.296±0.169，0.889± 0．040）and blank control group（1.031±0.301，0.884±0.043）(p＜0.01）.2.The inhibition rate of cells tranfected with pEX-2–IGFBP-rP1group in24h，48h，72h were (37.3±5.4)%、(39.9±4.7)%、(38.0±5.3)%, which were obviouslyelevated compared with pEX-2–Empty tranfected group（3.6±0.6）%,(4.0±0.5)%,(3.3±0.6）%and blank control group（2.7±0.3）%,(3.2±0.2)%,(2.4±0.2）%.Differences are statistically significant(p＜0.01）.3.After tranfected48h, the apoptosis rate of cells tranfected with pEX-2–IGFBP-rP1was（20.667±2.055）％，which was significantly higher than that inpEX-2–Empty tranfected group（3.967±0.351）％and blank control group（4.967±0.252）％(p＜0.01）.4..The S+G2／M phase cell ratio in pEX-2–IGFBP-rP1transfected group（30.980±1.461）%was significantly lower than that in the pEX-2–Empty tranfectedgroup（38.797±2.419）%or blank control group (37.800±0.350)%(p＜0.01）.ConclusionUp-regulation of IGFBP-rP1gene could induce cell apoptosis, inhibit cellproliferation and arrest cell cycle in HEC-1A. |
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