血小板与过表达平足蛋白的乳腺成纤维在乳腺癌原位生长中的作用及其机制

The roles and mechanism of platelets with podoplanin over - expressing human mammary fibro-blasts in the in situ growth of breast cancer

目的观察过表达平足蛋白（PDPN）的人乳腺成纤维细胞（HMF）在乳腺癌细胞株MDA-MB-231体外成瘤中的作用，探讨降低外周血小板数对过表达PDPN的HMF（HMF-P）促进肿瘤生长作用的影响及其机制。方法构建PDPN真核表达质粒PDPN-pEGFP-LV5，慢病毒转染HMF构建HMF-P，观察HMF-P对裸鼠成瘤的促进作用。应用血小板去除抗体11300构建血小板减少症小鼠模型，观察血小板数降低后HMF-P促进肿瘤作用的变化，Westernblot检测肿瘤生长因子的表达变化。结果HMF-P＋MDA-MB-23l共注射组瘤体体积最大，达3．16cm^3，而HMF-4-MDA-MB-231和MDA-MB-231组瘤体体积分别为1．93、0．52cm^3。降低血小板数后HMF-P＋MDA-MB-231组瘤体体积降至1．03cm^3，而HMF＋MDA-MB-231组瘤体积变化不明显。Westernblot检测显示HMF-P＋MDA．MB．231组血小板源性生长因子D（PDGF-D）的表达增加，降低血小板数后其表达明显降低。结论HMF．P可以促进MDA-MB-231的成瘤作用，其可能的作用机制是PDPN与浸润血小板相互作用促进其活化并释放PDGF-D相关。降低外周血血小板数以减少血小板肿瘤浸润可以抑制HMF-P促进肿瘤生长的作用。

Objective To confirm the role of podoplanin （PDPN） over- expressing human mammary fibroblasts （HMF） in tumorigenesis of breast cancer cell line MDA -MB -231, and study the effect and mechanism of reducing the peripheral platelet count in the progress of PDPN over - expressing HMF （ HMF - P） - induced tumor growth. Methods We firstly constructed PDPN eukaryotie expression plas- mid PDPN - pEGFP - LV5 and established HMF - P by lentivirus transfeetion. Then we investigated the effect of HMF - P on tumorigenesis in nude mice. We constructed a mouse model of thrombocytopenia by antibodies for mouse platelet depletion polyeonal purified R300 and investigated the effect of HMF - P again in these special mice. Lastly, the expression of some tumor growth factors was detected by Western blot- ting. Results MDA - MB - 231 cells commixed with HMF - P generated tumors of greatest volume 3. 16 cm3 ; while the volume of HMF ＋ MDA - MB - 231 and MDA - MB - 231 groups was 1.93 cm3 and 0. 52 cm3 respectively. The tumors volume in HMF - P ＋ MDA - MB -231 group decreased to 1.03 em3 in mice with thrombocytopenia, while the change in HMF ＋ MDA - MB - 231 groups was not obvious. Western blotting analysis showed that the expression of platelet - derived growth factor - D （ PDGF - D） in HMF -P ＋ MDA -MB -231 group was significantly increased, and that in thrombocytopenia group was significantly decreased. Conclusion HMF - P can promote the tumorigenesis of MDA - MB - 231. Its mechanism may be related to the interaction of PDPN with infiltrating platelets to promote its activation and release of PDGF - D. Reducing the peripheral blood platelet count to reduce platelet infiltration can inhibit the effect of HMF - P promoting tumor growth.