BMP-4 And Its Antagonism Noggin Involved In Human Prolactinomas And Their Molecular Mechanism

PART ONEExpression of BMP-4 and Ki-67 Protein in Prolactinomas and Their SignificancesObjective: To investigate the expressions of BMP-4 and Ki-67 in prolactinomas and their relationships with invasiveness characteristics.Methods: The expressions of BMP-4mRNA,BMP-4 and Ki-67 protein in 37 cases of prolactinomas and 8 cases of normal pituitary tissues samples were detected by immunohistochemical and in situ hybridizationtechnique,and the results were analysised by statistic method.Results: The expressions of BMP-4mRNA,BMP-4 and Ki-67 wasnegative in normal pituitary tissues,and those of BMP-4mRNA, BMP-4and Ki-67 protein in 37 cases of prolactinomas was positively relatedwith invasiveness grades (r=0.885,P<0.01) .The expressions of Ki-67protein in grades 2～3 were significantly different from those in grades0～ 1 in prolactinomas (P<0.05) .So the expressions of BMP-4mRNA,BMP-4 were more sensitive than the Ki-67 (P<0.05 ) .Conclusions: The BMP-4 was highly expressed in the prolactinomas andwas positively related with the invasiveness grades. BMP-4 is theparameter that can efficiently judge the invasiveness grades inprolactinomas.PART TWOThe Study of BMP-4 Accelerating PRL Secreting and Cell Proliferation in Human Prolactinoma in VitroObjective: To explore the BMP-4 how to regulate PRL secreting and cellproliferation in primal cultured prolactinoma cell.Methods: A total of 10 prlolactinoma patients were selected carefullyand were divided into two groups,one is sensitive to Bromocriptine ,the other is that nonsensitive to Bromocriptine. Every case were conducted by primal cell culture then were treeted by different concentration of BMP-4. The cell configuration was observed and PRL hormone was measured in defferemt time.Result: The culture medium of 5ng/ml BMP-4 can accelerate the secreting of PRL in prolactinoma cell, it can reach the most great effect in the concentration of 20ng/ml. BMP-4 can initiate the PRL accelerating secreting effect at 30 minute. What is more, BMP-4 can increase prolactinoma cell proliferation, but when the concentration is 50ng/ml,the BMP-4 effect of increasing secreting decrease. when 100ng/ml,the cell begin to die. The effects of the BMP-4 in sensitive group and nonsensitive group have no difference.Conclusion: Exogenous BMP-4 can accelerate prolactinoma secreting effect in vitro. Moreover, this effect is carried out by inducing the prolactinoma cell proliferation in sensitive and nonsensitive groups. So BMP-4 probably is the important step in prolactinama pathogenesis in cell signal conduction.PART THREEApoptosis of Human Prolactinoma Cell Induced by NogginObjective: To investigate the role of Noggin (BMP-4 antagonism) induce apoptosis of human prolactinoma cell.Methods: Prolactinoma cell culture in vitro. The growth inhibition and apoptosis induction effects of Noggin on prolactinoma cell were observed by MTT,flow cytometry with Annexin V,electronmicroscope. The expressions of BMP-4 protein and BMP-4mRNA were analysised by the method of cell immunohistochemistry,Western blot and reverse transcriptase polymerase chain reaction (RT-PCR).Results: The IC50 of Noggin on PRL cell was 18μg/ml,morever, Noggin inhibited prolactinoma cell growth in a dose-dependent manner. Flow cytometry,electronmicroscope both confirmed apoptosis of prolactinoma cell induced by Noggin. The expression levels of BMP-4mRNA and BMP-4 protein decreases in prolactinoma cells.Conclusion: Noggin can induce apoptosis of prolactinoma cell,it may be a promising medical therapy agent on prolactinoma.