Endogenous association of Bim BH3-only protein with Mcl-1, Bcl-xL and Bcl-2 on mitochondria in human B cells

Bim is an essential regulator of lymphoid system homeostasis and appears essential for B cell apoptosis induction. The mechanism by which Bim isoforms are held in an inactive form remains poorly documented in normal B cells. In the current study, we demonstrated that in normal tonsil B cells the three major Bim isoforms are strongly associated with the anti-apoptotic Bcl-2 family members Mcl-1, Bcl-2 and Bcl-x(L). On the other hand, only a weak association of BimEL and L with the dynein LC8 chain has been found. In addition, there is no free Bim in normal B cells. Moreover, subcellular fractionation demonstrated that Bim and the anti-apoptotic counterparts are localized preferentially in the mitochondria-rich fraction. The fact that most Bim was found in this fraction supports the hypothesis that it is sequestered by anti-apoptotic molecules in mitochondria where its pro-apoptotic activity is controlled. Of interest, BimS is essentially complexed to Mcl-1 and the Mcl-1/Bim complex is the most abundant among the three types of complexes. This supports the idea that this complex is critical for the control of B cell death. In conclusion, these results favor a model in which Bim release from anti-apoptotic proteins is a critical event for initiation of apoptosis.     

急性白血病患者Bcl-2／Jh基因的研究

目的 探讨急性白血病（AL）患者t（14；18）融合基因Bcl-2／Jh突变点，在AL诊治过程中的变化及预后判断的意义。方法 采集AL患者和正常人外周血，PCR方法检测Bcl-2／Jh基因3种不同重排方式的发生率。结果 完全缓解期白血病患者体内mbr、mcr和mdr的发生率分别为46．6％、41．2％和13．8％。发生3种易位的机率为1．72％、2种易位的机率为5．2％。结论 Bcl-2／Jh在AL患者治疗前后的发生率和重排率虽有不同，可在一定程度上反映疗效。     

米非司酮对早孕绒毛滋养层细胞Bcl-2和caspase-3表达的影响

探讨米非司酮对人早孕绒毛滋养细胞中Bcl—2和caspase-3表达的影响及其在滋养细胞凋亡中的作用。方法：将105例自愿要求终止妊娠的早孕妇女随机分成两组，即米非司酮流产组(55例)及人工流产组(50例)。采用免疫组化染色方法检测早孕妇女的绒毛组织中Bcl—2和caspase-3的表达。结果：米非司酮组与人流组绒毛滋养细胞中Bcl—2的表达率分别为54．6％和88．0％；caspase-3的表达率分别为89．1％和42．0％。米非司酮组与人流组相比较绒毛滋养层细胞Bcl—2呈低表达(P＜0．01)，caspase-3呈高表达(P＜0．01)。结论：Bcl—2和caspase-3在米非司酮诱导的早孕绒毛滋养层细胞凋亡的信号传导中起关键作用。     

P53融合蛋白的原核表达及其单克隆抗体的制备

目的 为研制出能特异与Ｐ＾５３结合的单克隆抗体,使对Ｐ＾５３的检测得到更为广泛的应用。方法 用ＰＣＲ技术扩增编码人Ｐ＾５３Ｎ－端１８０个氨基酸的ＤＮＡ片段并将其克隆在谷胱苷肽转移酶（ＧＳＴ）表达质粒Ｐ＾ＧＥＸ－２Ｔ中。用该重组质粒转化大肠杆菌ＪＭ１０９,并经异丙基β－Ｄ硫代半乳糖苷（ＩＰＴＧ）诱导产生Ｐ＾５３－ＧＳＴ融合蛋白。用Ｐ＾５３－ＧＳＴ免疫ＢＡＬＢ／ｃ小鼠。常规细胞融合,间接酶联免疫吸附试     

BNIP3 expression in follicular lymphoma

AIMS: To investigate the role of BNIP3, a 19-kDa interacting protein of the Bcl-2 family, alongside Bcl-2 in follicular lymphoma in comparison with reactive lymphoid hyperplasia. The results were compared with those from p53 and caspase-3 (apoptotic markers) and Ki67 (proliferation marker). METHODS AND RESULTS: Immunohistochemistry using monoclonal antibodies showed BNIP3 to be strongly expressed in most follicular lymphomas but to be weak to negative in all of the reactive cases. There was also an inverse relationship with Bcl-2 expression. There was no correlation of BNIP3 immunoreactivity with proliferation and caspase and p53 were virtually negative in all follicular lymphomas and reactive lymphoid cases. CONCLUSIONS: BNIP3 is strongly expressed in most follicular lymphomas, especially those that are Bcl-2 negative. BNIP3 may serve as a marker of more aggressive behaviour in follicular lymphoma and be useful diagnostically in the distinction from reactive lymphadenitis.     

IL‐15 modulates the balance between Bcl‐2 and Bim via a Jak3/1‐PI3K‐Akt‐ERK pathway to promote CD8αα+ intestinal intraepithelial lymphocyte survival

IL‐15 is an essential survival factor for CD8αα⁺ intestinal intraepithelial lymphocytes (iIELs) in vitro and in vivo. However, the IL‐15‐induced survival signals in primary CD8αα⁺ iIELs remains elusive. Although Bcl‐2 level in CD8αα⁺ iIELs positively correlates with IL‐15Rα expression in the intestinal epithelial cells, overexpression of Bcl‐2 only moderately restores CD8αα⁺ γδ iIELs in Il15^?/? mice. Here, we found that IL‐15 promptly activated a Jak3‐Jak1‐PI3K‐Akt pathway that led to the upregulation of Bcl‐2 and Mcl‐1. This pathway also induced a delayed but sustained ERK1/2 activation, which not only was necessary for the maintenance of Bcl‐2 but also resulted in the phosphorylation of extra‐long Bim at Ser⁶⁵. The latter event facilitated the dissociation of Bim from Bcl‐2 without affecting Bim abundance in IL‐15‐treated CD8αα⁺ iIELs. Using an adoptive cell transfer approach, we found that either overexpression of Bcl‐2 or removal of Bim from CD8αα⁺ iIELs promoted their survival in Il15ra^?/? mice. Taken together, IL‐15 promotes CD8αα⁺ iIEL survival by both increasing Bcl‐2 levels and dissociating Bim from Bcl‐2 through activation of a Jak3‐Jak1‐PI3K‐Akt‐ERK1/2 pathway, which differs from a previously reported IL‐15‐induced survival signal.     

Immunohistological expression of HIF‐1α, GLUT‐1, Bcl‐2 and Ki‐67 in consecutive biopsies during chemoradiotherapy in patients with rectal cancer

The aim of this study was to describe the dynamics of HIF‐1α, GLUT‐1, Bcl‐2 and Ki‐67 during chemoradiotherapy (CRT) of rectal cancer, and to investigate the fluctuation of these biomarkers in relation to pathological response to CRT. The study included 86 patients with rectal adenocarcinoma receiving preoperative CRT (>50.4 Gy and Uracil/Tegafur). Immunohistological expressions of HIF‐1α, GLUT‐1, Bcl‐2 and Ki‐67 were investigated in biopsies taken before treatment, after 2, 4 and 6 weeks of CRT and in specimens from the operation. Decreasing expressions of HIF‐1α, Bcl‐2 and Ki‐67 were observed during CRT, whereas GLUT‐1 overall was unchanged. No significant changes of the markers were observed in the interval between CRT and surgery. A significant association was observed between the presence of residual carcinoma after 6 weeks of treatment and pathological response to CRT, but no association was seen between the fluctuations of any of the markers and response to CRT. This unique material containing specimens before, after and during CRT for rectal cancer demonstrated biological dynamics in HIF‐1α, Bcl‐2 and Ki‐67, but not GLUT‐1, expression during CRT, and a significant association was seen between the presence of residual carcinoma after 6 weeks of treatment and pathological response to CRT.     

Effect of IL-5, glucocorticoid, and Fas ligation on Bcl-2 homologue expression and caspase activation in circulating human eosinophils

IL-5 is a potent eosinophil viability-enhancing factor that has been strongly implicated in the pathogenesis of IgE-mediated inflammation in vivo. Recently published data have suggested that IL-5 (and related cytokines) may act by altering the expression of the anti-apoptotic regulator Bcl-2 or its homologues, but this is controversial. The behaviour of the recently described pro-apoptotic cysteine proteases (caspases) in eosinophils after IL-5 treatment has not been explored. We examined the effect of IL-5 on the expression of four major Bcl-2 homologues, as well as on the expression/activation of key members of the caspase cell death cascade in cultured circulating human eosinophils. The effect of relevant inducers of eosinophil apoptosis (glucocorticoid and Fas ligation) on these regulatory proteins was also examined. We observed baseline expression of the anti-apoptotic Mcl-1 and pro-apoptotic Bax proteins in immunoblots of eosinophil lysates, but not Bcl-x, Bcl-2. IL-5 treatment had the effect of maintaining this basal level of expression over time without altering the balance of Bcl-2 homologues. The (upstream) caspase 8 and (downstream) caspase 3 proenzymes were detected in eosinophils at baseline, and were processed during spontaneous and stimulated eosinophil death. IL-5 completely blocked caspase processing in spontaneous and dexamethasone-induced cell death, and significantly slowed processing during Fas ligation. Our data do not support the theory that IL-5 acts by altering the balance of anti-apoptotic and pro-apoptotic Bcl-2 homologues, but suggest that it may act by regulating activation of the caspase cell death cascade.     

原发性胆囊癌CD44v6和bcl-2的表达及其与临床病理的关系

目的　探讨CD44v6和bcl 2蛋白在原发性胆囊癌组织中的表达及其与癌组织类型、病理分级和转移状况的关系 ,以及CD44v6表达与bcl 2表达的相关性。方法　应用免疫组织化学方法检测 50例原发性胆囊癌、2 0例胆囊腺瘤和 1 0例慢性胆囊炎组织中CD44v6和bcl 2蛋白的表达。结果　胆囊癌组织中CD44v6和bcl 2表达阳性率分别为82 .0 %和 60 .0 % ,均明显高于胆囊腺瘤 (分别为 45 .0 %和 30 .0 % ,P<0 .0 5) ,并随着胆囊癌细胞分化程度的减低、病理分级的增高和转移而明显增高 (P<0 .0 5)。同时 ,CD44v6的表达与bcl 2表达呈正相关 (r =0 .36 ,P<0 .0 5)。结论　CD44v6和bcl 2均是胆囊癌高度恶性和预后不良的重要指标。胆囊癌CD44v6表达与bcl 2蛋白表达可能具有相互协同作用。