Changed Bcl:Bax ratio in endometrium of patients with unexplained infertility

Apoptosis has been shown to be an important regulator of endometrial function during the menstrual cycle and implantation. Recently, some possible implantation defects were identified in patients with unexplained infertility. In this study, we investigated the role of spontaneous apoptosis, which is regulated by death regulatory genes, such as Bcl-2, Bax, p53, and isoenzymes of nitric oxide synthases; eNOS and iNOS during the implantation window in women with unexplained infertility. Endometrial samples were evaluated from fertile (n=15) and unexplained-infertile women (n=15) during post-ovulatory 7th or 8th day of their menstrual cycles. Apoptotic cells were detected using the dUTP nick-end labelling assay and Bcl-2, Bax, p53, iNOS and eNOS were assessed immunohistochemically. Reduced apoptotic cells, weak immunoreactivity of p53 and strong immunoreactivity of Bcl-2 were observed in the unexplained-infertile group compared with the fertile group (p<0.001). Bax intensity was similar in both groups. While weak iNOS immunoreactivity was detected in both groups, moderately increased eNOS immunoreactivity was observed in infertile cases. Spontaneous apoptosis is reduced in the endometrium of unexplained-infertile women, and is associated with the changed Bcl-2:Bax ratio. This finding may be a contributing factor to defective implantation causing infertility in this group of patients.     

Apoptosis of colorectal adenocarcinoma (COLO 201) by tumour necrosis factor-alpha (TNF-α) and/or interferon-gamma (IFN-γ), resulting from down-modulation of Bcl-2 expression

Fas antigen is constitutively expressed in the normal colon epithelium, but considerably diminished in most colorectal carcinomas. In the present study, we examine the relationship between Fas antigen expression and apoptosis using the colorectal carcinoma cell line COLO 201, on which a low grade of Fas antigen is expressed. Anti-Fas antibody had no effect on the induction of apoptosis of COLO 201. However, TNF-α and/or IFN-γ, independently and additively, up-regulated Fas antigen expression on COLO 201 and induced apoptosis in a dose-dependent manner. Both cytokines also increased the COLO 201 sensitivity to anti-Fas antibody, resulting from the down-modulation of Bcl-2 and the up-regulation of Bax. These findings indicate that cytokine(s) plus anti-Fas antibody (which mimics natural Fas ligand) are more effective in inducing apoptosis of COLO 201 than cytokine(s) alone. These findings suggest that immunotherapy in combination with cytokine(s) and lymphokine-activated killer (LAK) cells will become a more effective therapy for cancer than cytokine(s) or LAK cells alone, since the Fas ligand is expressed on activated T cells, natural killer cells and macrophages.     

The role of Bcl-2 family members in the progression of cutaneous melanoma

The overwhelming problem of cutaneous melanoma is chemoresistance. Subversion of the biochemical changes that lead to chemoresistance intersects the apoptosis pathways. The mitochondrion has been a focal point of this intersection for the development of therapeutic strategies aimed at reducing the progression of melanoma. The Bcl-2 family of apoptotic regulators is arguably the most pivotal component to this mitochondrial response. The shear number of studies conducted on the relationship between melanoma and Bcl-2 members prompted us to evaluate the literature available and discern some rational utility of the data. We have found that there are striking inconsistencies for the expression of Bcl-2 family proteins with melanoma progression, particularly for Bcl-2. Roughly one-third of the data suggests an increase in Bcl-2 expression with advancing melanoma, while another third suggests a decrease. Furthermore, the remaining third found on the whole, a detectable level of Bcl-2 in all tissues of melanocytic origin. These discrepancies are difficult to rectify in light of the apparent success of recent clinical trials utilizing Bcl-2 antisense strategies. The general consensus in the literature is that pro-apoptotic Bax is decreased with melanoma progression while anti-apoptotic Bcl-x_L and Mcl-1 appear to increase with progression. We suggest that the biochemical techniques being used for analysis present too great of a heterogeneity, which could be mitigated with more standard procedures and reagents. Finally the utility of ‘multi-specific’ antisense tactics could be a more effective way of targeting advanced melanoma disease. This revised version was published online in July 2006 with corrections to the Cover Date.     

肾母细胞瘤经动脉化疗栓塞术疗效机制探讨

目的： 探讨肾母细胞瘤术前经动脉化疗栓塞的疗效机制。方法: 17例肾母细胞瘤患儿介入治疗后再行肿瘤切除，另 22例行单纯手术切除。对照分析2组肾母细胞瘤样本中细胞和间质的变化，采用原位细胞凋亡(TUNEL 法) 检测瘤细胞凋亡，并通过免疫组化法检测瘤细胞P53、Bcl-2 和Bax蛋白的表达。术后随访2年以上。结果: 介入组与单纯手术组的肿瘤坏死区域平均面积分别为60%、15 %（Uc = 2.84）；肿瘤组织呈X₃、X₄退变者分别为58.8%（10/17）和4.55%（1/22）（2c= 11.4）、间质纤维组织增生程度中、重度变化者分别为64.7%（11/17）和18.2%（4/22）（Uc = 2.72）、淋巴细胞侵润者分别为70.6%（12/17）和18.2%（4/22）（2c=10.9），2组有显著差异（P<0.01）；介入组肿瘤细胞分裂指数的中位数为0.2/10高倍视野，明显低于单纯手术组的1.4/10高倍视野（Uc = 54.50 ，P<0.01）；94.9(37/39)的病例中均有不同数量的阳性凋亡细胞出现。介入组肿瘤细胞凋亡指数的中位数为25.9/10高倍视野，明显高于单纯手术组的12.8/10高倍视野（Uc = 117.00，P<0.05）。P53和Bcl-2蛋白表达与瘤细胞凋亡及分化程度均无相关性（P>0.05），但Bax 蛋白在介入组瘤细胞表达率（80.0%）明显高于单纯手术组（40.0%），差异显著（P<0.05）。介入组2年无瘤生存率为73.3%（11/15），单纯手术组为42.9%（6/14）。结论: 经动脉化疗栓塞治疗能够有效杀伤肿瘤细胞、抑制肿瘤生长，诱导由Bax蛋白介导的肿瘤细胞凋亡。     

舌癌术前化疗PCNA、bcl-2、Bax基因表达及临床意义

目的 :通过舌癌术前化疗增殖细胞核抗原 (PCNA )和细胞凋亡相关基因 bcl- 2、Bax表达的研究 ,探讨舌癌的化疗作用机制。 方法 :对舌乳头状瘤、舌癌和舌癌术前化疗标本共 34例 ,采用免疫组织化学染色技术——酶标链亲和素生物素法 (L SAB)染色并进行光镜下观察。结果:PCNA在舌癌中的表达最强 ,在舌癌术前化疗中的表达明显减弱 (P <0 .0 5 ) ,其与舌乳头状瘤表达相似 (P >0 .0 5 )。 bcl- 2在舌癌术前化疗及舌乳头状瘤中低表达(P >0 .0 5 ) ,舌癌中表达明显增强 (P <0 .0 5 )。Bax在舌癌组和乳头状瘤组中表达有明显差异 (P <0 .0 5 )。结论 :化疗药物抑制肿瘤生长的机制可能与抑制肿瘤细胞增殖和诱导肿瘤细胞程序性死亡有关 ,提示舌癌术前化疗对肿瘤的预后有重要意义。     

血管紧张素Ⅱ上调BaX表达诱导人内皮细胞凋亡

为了研究血管紧张素Ⅱ(AngⅡ)诱导凋亡的机制,将人脐静脉内皮细胞培养至第3代,用不同浓度Ang Ⅱ培养不同时间,用TUNEL检测细胞凋亡.Bax和Bcl-2蛋白表达用Western Blot和图像分析法测定.结果发现Ang Ⅱ组的凋亡阳性率极显著高于对照组;Bax的表达极显著地升高且具有时间和剂量依赖性,Bcl-2无显著变化,Bax/Bcl-2比值极显著地增加.提示AngⅡ通过诱导Bax的高表达,致Bax/Bcl-2比值极显著地增加而诱发凋亡.     

喉癌组织Bc1-2和Bax基因蛋白表达及其临床相关性研究

目的　探讨喉癌组织Bc1 2和Bax基因蛋白表达与喉癌发生、发展的关系。方法　采用免疫组化SP法测定 5例正常人声带组织和 73例喉癌组织标本中Bc1 2和Bax基因蛋白表达。结果　喉癌组织中Bc1 2基因蛋白表达阳性检出率 45 .2 % ,喉癌组织中Bax基因蛋白达阳性检出率 6 0 .3% ,与正常人相比 ,均无显著性差异 (P >0 .0 5 )。喉癌组织中Bc1 2及Bax基因蛋白的表达呈明显的负相关关系 ,r值 - 0 .71,P <0 .0 5。结论　喉癌组织中Bc1 2和Bax基因蛋白表达的失调可能与喉癌的发生、发展有关。     

凋亡相关基因bcl-2及bax在肝癌的表达及意义

目的 :探讨凋亡抑制基因和凋亡促进基因 bax表达与肝癌生物学行为的关系及对肝癌预后的关系。方法 :用免疫组化L SAB法测定 40例肝癌细胞和 16例正常肝组织的 bcl- 2和 bax蛋白表达水平。结果 :bcl- 2及 bax蛋白表达阳性率在正常肝组织和肝细胞癌分别为 12 .5 % (2 / 16 )、45 .0 % (18/ 40 )、87.5 % (14/ 16 )、5 2 .5 % (2 1/ 40 ) ,两组间差异有显著性 (P<0 .0 5 )。 bcl-2、bax蛋白表达与肿瘤病理分级、分期、淋巴结转移及患者预后相关。结论 :Bcl- 2和 Bax蛋白的表达参与了肝癌的发生及进展 ,并存在相互作用的关系。 Bcl- 2蛋白表达在肝癌有独立预后价值。     

中华眼镜蛇毒组分C抗白血病作用的实验研究

目的：研究眼镜蛇毒组分Ｃ对白血病细胞的直接作用及机制。方法：应用ＭＴＴ、ＤＮＡ电泳、流式细胞仪ＲＴ－ＰＣＲ等方法,观察眼镜蛇毒组分Ｃ对ＨＬ６０等９株白血病细胞系的毒性作用、量效关系及白血病细胞经过眼镜蛇毒组分Ｃ处理后的生物化学、Ｂｃｌ－２／Ｂａｘ表达水平变化。结果：眼镜蛇毒组分对９株人白血病细胞系均有明显的抑制作用,ＩＣ５０为０．００４６～４．４０μｇ／ｍｌ,且呈较好的量效关系（ｒ为０．６６～０．     

Estrogen increases intracellular p26Bcl-2 to p21Bax ratios and inhibits taxol-induced apoptosis of human breast cancer MCF-7 cells

Recent studies have demonstrated that following estrogen ablation, estrogen responsive breast cancer cells undergo apoptosis. In addition, estrogen receptor (ER) expression has been strongly correlated with the expression of the bcl-2 gene product, p26Bcl-2 protein, which is known to inhibit apoptosis. In the present studies, we investigated whether estrogen affects the intracellular levels of p26Bcl-2 and thereby modulates taxol-induced apoptosis of estrogen responsive human breast cancer MCF-7 cells. Transfer of MCF-7 cells to a culture-medium without estrogens reduced their intracellular p26Bcl-2 levels by 50%. Inclusion of 0.1 M estradiol in the medium produced approximately a four-fold increase in p26Bcl-2, but not p29Bcl-xL or p21Bax levels; the expression of the c-myc and mdr-1 genes remained unchanged. Estradiol-induced four-fold increase in the ratio of the p26Bcl-2 to p21Bax levels caused a significant decline in the lethal, kilobase size DNA fragments of apoptosis, which had resulted when MCF-7 cells were cultured in a medium without estrogen. In addition, in MCF-7 cells, estradiol-induced increase in the intracellular p26Bcl-2 to p21Bax ratios was associated with a significant reduction in the large-sized DNA fragmentation induced by treatment with taxol. The increased ratios also protected MCF-7 cells against taxol-mediated cytotoxicity as assessed by the MTT assay. These results suggest that by modulating p26Bcl-2 levels, estrogens may affect the antitumor activity of taxol and potentially of other anti-breast cancer drugs against estrogen responsive human breast cancer cells.