微囊化肿瘤细胞生长及其基因表达的研究

Gene expression and growth features of microencapsulated multicellular tumor spheroid

目的以人乳腺癌细胞系(MCF-7)为模型,探讨肿瘤细胞在微囊化环境中的生长特性和对基因表达的影响。方法使用大功率高压脉冲微胶囊制备仪制备微囊化MCF-7细胞,观察细胞的生长和代谢特性;待微囊内的细胞体外生长成团后固定、石蜡包埋、制作连续切片,HE染色并免疫组化检测HIF-1、cyclin D1、VEGF、p53、PCNA、BrdU等相关基因的表达。以平面培养细胞做对照。结果人乳腺癌细胞微囊化后可继续生长增殖并聚集成团,同时消耗葡萄糖产生乳酸。微囊化肿瘤细胞表现出较强的增殖活性;当微囊内的细胞团增大到一定程度时中心可出现坏死区,但分布于团块外层的细胞仍具有增殖活性;HIF-1和cyclin D1主要在位于细胞团内部的细胞表达;VEGF的表达与细胞所处位置无关;未检测到p53的阳性表达。平面培养MCF-7细胞可检测到PCNA和VEGF的表达。结论微囊化肿瘤细胞呈三维立体方式生长并存在相关基因的表达,是一种介于体外单层培养和体内移植瘤试验之间的新型肿瘤细胞特性研究、抗肿瘤药物筛选的模型,具有简单、方便和经济等特点。

Objective：To investigate the effect of microencapsulation environment on growth features and gene expression of Human MCF-7 breast cancer cells. Methods： Human MCF-7 breast cancer cells were encapsulated in alginate-poly- L -lysine-algi- nate （APA） microcapsules using electrostatic droplet generator. The cell proliferation and metabolism of the microencapsulated muhicellular tumor spheroid （MMTS） were observed. MMTS were fixed, paraffin-embedded, sliced, and stained with HE. Expressions of HIF-1 ,cyclin D1 ,VEGF,p53 ,PCNA,BrdU were examined by immunohistochemistry. MCF-7 monolayer cells were used as control. Results： Microencapsulated tumor cells grew and proliferated into clump accompanied with glucose consumption and lactic acid generation. Histological analysis indicated that the proliferating cells were mainly localized to the periphery of the cell spheroid and the necrotic cells were in the core as the cell spheroid was enlarged. Proliferating cells were restricted to the outer two or three cellular layers in microcapsules. HIF-1 and cyclin D1 were expressed in the inner cellular layer, but VEGF in all the cellular layers. Expression of p53 gene was not observed. Expression of PCNA and VEGF could be detected in monolayer culture. Conclusions： The MMTS showed three-dimensional （3-D） cell growth pattern and related gene expression. It is a simple,convenient,and economic assay between monolayer culture in vitro and transplanted tumors in vivo. It has the potential for screening anti-tumor agents and investigating biological features of tumors.