Caveolin-1抑制胰腺癌细胞PANC1的体内外生长和增殖

窖蛋白-1(caveolin-1)是胞膜窖(caveolae)中重要的结构和功能蛋白.Caveolin-1参与细胞的多种生命活动并与恶性肿瘤的发生相关.为探讨caveolin-1对胰腺癌细胞PANC1的体外增殖、迁移、侵袭以及裸鼠体内成瘤能力的影响,通过基因转染技术培育caveolin-1过表达细胞株PANC1/cav-1作为实验组,转染空载体细胞株PANC1/vector作为对照组,采用RT-PCR及Western blot方法检测caveolin-1的表达量,流式细胞术分析细胞周期,软琼脂细胞克隆实验检测细胞增殖能力,侵袭小室实验检测癌细胞迁移和侵袭的能力,建立裸鼠皮下种植瘤模型并检测肿瘤组织的增殖与凋亡.PANC1/cav-1中的caveolin-1表达稳定,表达量明显高于对照组细胞株和亲本细胞株(P<0.01),细胞周期检测显示大量PANC1/cav-1细胞被抑制于G0/G1期,caveolin-1抑制PANC1的增殖,迁移和侵袭能力.在裸鼠的体内实验中,caveolin-1显著抑制PANC1细胞在裸鼠体内的生长,Ki-67染色和TUNEL染色表明在PANC1细胞中过表达caveolin-1,可以抑制肿瘤增殖并诱导肿瘤凋亡.上述结果表明,caveolin-1可能通过对胰腺癌细胞周期的影响(抑制于G0/G1期),抑制胰腺癌PANC1细胞在体内外的增殖、迁移和侵袭,并导致肿瘤凋亡.

The Inhibition Effect of Caveolin-1 on PANC1 Human Pancreatic Tumor Growth In vitro and In vivo

Caveolin-1 is a transmembrane protein and essential structural constituent of the caveolae membrane. Caveolin-1 has been involved in multiple cellular functions and oncogenesis. To investigate the roles of caveolin-1, stable transfectants were established in PANC1 pancreatic adenocarcinoma cells which had up-regulated caveolin-1 expression. The plasmid pCI-neo-cav-1 and its corresponding empty vector (pCI-neo) were transfected into PANC1 cell lines. The expression of caveolin-1 in these three cell lines was determined by RT-PCR and Western blot. Cell cycle phase distribution was determined by flow cytometry. The colony formation ability of tumor cells was detected by anchorage-independent growth assay. Cell migration and invasion were assayed in MilliCell chambers. Xenograft tumor models in nude mice were developed. Immunohistochemistry was used to characterize Ki-67 levels in residual tumors, and apoptosis was evaluated by TUNEL technique. Caveolin-1 overexpression inhibited PANC1 cell proliferation by arresting the cell cycle in the G0/G1 phases and also markedly reduced the capacity of the cells to form colonies in soft agar. Additionally, caveolin-1 overexpression dramatically inhibited cells to invade and migrate. Importantly, in vivo experiments demonstrated that overexpression of caveolin-1 resulted in significant growth inhibition of the xenograft pancreatic tumors. Immunohistochemistry analysis demonstrated both a marked decrease in the number of proliferating tumor cells and an increase in the number of apoptotic tumor cells in PANC1/cav-1 xenograft tumors. The results provide an initial demonstration that caveolin-1 can function as a tumor suppressor rather than as a tumor promoter in PANC1 cells.