苦瓜蛋白诱导K562细胞凋亡及其对Bcl-2、PCNA蛋白表达的影响

目的：观察苦瓜蛋白是否具有诱导K562细胞凋亡的生物学活性，探讨苦瓜蛋白对K562细胞Bcl-2及PCNA表达水平的影响及其作用的分子机制。方法：以一定浓度的苦瓜蛋白处理K562细胞12～72小时，CCK-8检测其对细胞生长的影响；流式细胞术（AnnexinV）、细胞形态学（光镜及电镜）等方法检测细胞凋亡；同时应用流式细胞术检测Bcl-2及PCNA蛋白表达的变化。结果：苦瓜蛋白对K562细胞生长具有明显的抑制作用；流式细胞术及形态学观察（光镜及电镜）证实一定作用浓度的苦瓜蛋白可诱导K562细胞发生明显的细胞凋亡，且随着作用时间的延长细胞凋亡率逐渐升高。苦瓜蛋白处理组K562细胞中Bcl-2及PCNA蛋白的表达分别为0．33％和98．36％，对照组分别为74．03％和97．63％。结论：苦瓜蛋白对K562细胞生长具有明显抑制作用，其作用主要通过诱导K562细胞产生细胞凋亡．而不是抑制细胞增殖。苦瓜蛋白诱导K562细胞凋亡过程中，Bcl-2蛋白表达的下调对调控细胞凋亡有重要作用。

Induction of apoptosis by Momordin in erythroleukemic K562 cells and its effect on Bcl-2 and proliferating cell nuclear antigen

Objective:To explore the apoptosis inducing activity of Momordin from Momordica charantia seeds and its effect on the expression of Bcl-2 gene and proliferating cell nuclear antigen(PCNA).Methods:After the treatment of K562 cells with appropriated concentration Momordin for 12 to 72 hours, CCK-8 test was employed to determine K562 cells growth; FACScan(FITC-Annexin V staining), Light and electron microscopy were used to detect apoptosis; The expressions of Bcl-2 and PCNA were examined by FACScan(FITC-Bcl-2 or FITC-PCNA staining).Results:CCK-8 test showed K562 cells growth was significant inhibited by Momordin; markedly apoptosis was detected by cell morphology and FACScan(FITC-Annexin V) in K562 cells after treatment by appropriated concentration Momordin and increased in a time-dependent manner; The expressions of Bcl-2 and PCNA in Momordin treated K562 cells were 0.33% and 97.63% respectively, and in negative Momordin treated K562 cells were 74.03% and 98.36% respectively.Conclusion:Momordin can significantly inhibit the growth of K562 cell, its function is performed by inducing apoptosis but not by inhibiting proliferation. Bcl-2 down-expression may probably function as an important regulator in the process of apoptosis induced by Momordin.