The Study Of The Expression Of CEACAM1 In Breast Tissues And Its Roles In Breast Cancer Progression

Objective: Our study aims to investigate the expression of CEACAM1 in breast tissues and determine its roles during breast cancer progression,especially cancer metastasis and angiogenesis.Methods: 1.The expression and location of CEACAM1 in breast cancer tissues were observed by immunohistochemistry(IHC)staining,and the relationships of CEACAM1 and cancer metastasis as well as angiogenesis were assessed.2.The soluble CEACAM1 levels in culture medium of breast cancer cells were determined by enzyme-linked immunosorbent assays(ELISAs).3.The membrane-bound CEACAM1 in breast cancer cells were observed by immunoflorescence staining.4.The CEACAM1 mRNA and protein expression levels in breast cancer cells were measured using quantitative real-time PCR and western blot assay,respectively.5.A CEACAM1-expressing vector was constructed and transiently transfected into breast cancer cell lines BT549 and Hs578 T.6.Transwell invasion and wound-healing assays were performed to investigate the effects of CEACAM1 on breast cancer cell invasion and migration.7.Colorimetric CCK-8 assay was used to determine the influence of CEACAM1 on breast cancer cell proliferation.8.Western blot assays were conducted to explore the changes of EMT-related markers,as well as the phosphorylation of intracellular signal molecules following CEACAM1 over-expression in breast cancer cells.9.The microvessel density(MVD)of breast cancer was evaluated by IHC staining on tissue sections and then the association between MVD and clinical parameters was determined.10.The conditioned media of breast cancer cells with CEACAM1 transfection were collected and subsequently used in the tube formation assay based on HUVEC.11.The soluble VEGFs levels in the conditioned media of breast cancer cell with CEACAM1 transfection were evaluated by ELISA and compared with those of controls.Results: 1.CEACAM1 expression was reduced in breast cancer tissues compared withnon-tumor adjacent tissues or benign disease tissues by IHC staining.2.The soluble CEACAM1 was detectable in the culture medium of breast cancer cells(BT549,Hs578 T,MDA-MB-468,MDA-MB-231,T47 D,and MCF7)and its levels were significantly lower than normal breast epithelial cells MCF10 A,which was used for a normal control.3.Breast cancer cells showed relatively lower expression of membranous CEACAM1 by IF analysis.4.By real-time RT-PCR and western blot analysis,we found that CEACAM1 mRNA and protein expression levels were down regulated in breast cacner cells.5.IHC result indicated CEACAM1 expression inversely correlated with lymph node metastasis in breast cancer.6.CEACAM1 mRNA expression correlated with reduced metastatic potential of human breast cancer cell lines.7.Overexpression of CEACAM1 in breast cancer cells resulted in substantial decreases in cell invasion and migration.8.CEACAM1 induced a regulation of MMP2/TIMP2 balance and E-cadherin/N-cadherin balance in breast cancer cells.9.CEACAM1 diminished the phosphylation of Smad2 and STAT3 but did not influence the total protein levels of them.10.IHC staining results indicated that the MVD in breast cancer tissues was inversely related to CEACAM1 expression.11.The conditioned media of CEACAM1-transfected breast cancer cells decreased HUVEC tube formation as compared with wide types.12.The level of VEGF-A in conditioned media of CEACAM1-transfected breast cancer cells was significantly lower that those of controls.Conclusion: 1.CEACAM1 is down-regulated in breast cancer;2.CEACAM1 can suppress breast cancer cell invasion and migration by regulating two balances of MMP2/TIMP2 and N-/E-cadherins as well as induction of EMT reversion;3.CEACAM1 can inhibit angiogenesis by decreasing VEGF-A secretion in breast cancer;4.CEACAM1 may function as a tumor suppressor in breast cancer and restoring CEACAM1 expression may open up a novel revenue for the therapy of patients with breast cancer.