Attari Farnoosh, Sepehri Houri, Delphi Ladan, Goliaei Bahram
Dept. of Animal Biology, School of Biology, College of Scienc, University of Tehran, Tehran, Iran.
Institute of Biochemistry and Biophysics (IBB), University of Tehran, Tehran, Iran.
Iran Biomed J. 2009 Oct;13(4):229-36.
Pectin is composed of complex polysaccharides that can inhibit cancer metastasis and proliferation with no evidence of toxicity. In the present study, the apoptotic and necrotic effects of pectic acid (PA) on the rat pituitary GH3/B6 tumor cells has been investigated.
GH3/B6 cells were cultured in the Ham's F12 medium enriched with 15% horse serum and 2.5% fetal bovine serum for 3 days. Then, they were treated by various amounts of PA in different periods (6, 24 and 48 hours). Bromocriptine was used as positive control and the cell viability was detected by MTT test. The nuclear morphology of cells was explored by florescent stains including acridine orange (AO)/ethidium bromide (EB). In addition, percentages of apoptotic and necrotic cells were studied with triphosphate nick-end labeling (TUNEL) assay, cell cycle analysis and propidium iodide (PI) staining.
Long-term incubation with PA results in increased cell death and DNA damage as detected by MTT assay and AO/EB staining. TUNEL assay showed that PA (100 microg/ml to 1 mg/ml) could induce apoptosis in a dose-dependent manner, while higher concentrations of PA (2.5 and 5 mg/ml) induced necrosis which was confirmed by PI staining. Furthermore, cell cycle analysis indicated that PA induced sub G1 events, and DNA fragmentation was also correlated with the number of the apoptotic cells.
It can be concluded that PA is responsible for apoptosis in the rat pituitary tumor cells. Therefore, one may suggest that this group of polysaccharides can be used in treatment of pituitary tumors.
果胶由复杂多糖组成，可抑制癌症转移和增殖且无毒性证据。在本研究中，已对果胶酸（PA）对大鼠垂体GH3/B6肿瘤细胞的凋亡和坏死作用进行了研究。
将GH3/B6细胞在富含15%马血清和2.5%胎牛血清的Ham's F12培养基中培养3天。然后，在不同时间段（6、24和48小时）用不同量的PA处理它们。溴隐亭用作阳性对照，通过MTT试验检测细胞活力。用吖啶橙（AO）/溴化乙锭（EB）等荧光染料探索细胞的核形态。此外，用三磷酸核苷酸末端标记（TUNEL）试验、细胞周期分析和碘化丙啶（PI）染色研究凋亡和坏死细胞的百分比。
MTT试验和AO/EB染色检测显示，长期用PA孵育会导致细胞死亡增加和DNA损伤。TUNEL试验表明，PA（100微克/毫升至1毫克/毫升）可呈剂量依赖性诱导凋亡，而较高浓度的PA（2.5和5毫克/毫升）诱导坏死，这通过PI染色得到证实。此外，细胞周期分析表明PA诱导亚G1期事件，DNA片段化也与凋亡细胞数量相关。
可以得出结论，PA导致大鼠垂体肿瘤细胞凋亡。因此，可以认为这组多糖可用于垂体肿瘤的治疗。
