Fibroblast Growth Factor Receptor 3 (FGFR3) Associated with the CD20 Antigen Regulates the Rituximab-induced Proliferation Inhibition in B-cell Lymphoma Cells

Rituximab is reported to inhibit the proliferation of lymphoma cells through an unknown CD20-mediated signal transduction pathway. Herein, we investigated cell surface molecules involved in the CD20-mediated signal transduction pathway by using a recently developed technique named enzyme-mediated activation of radical sources. Using this method, we found that under stimulation with rituximab and another anti-CD20 antibody B-Ly1, CD20 was physically associated with fibroblast growth factor receptor 3 (FGFR3) as well as some other receptor tyrosine kinases in Raji cells. However, under stimulation with a noncytotoxic anti-CD20 antibody 2H7, CD20 was not associated with FGFR3 but with the PDGF receptor β. When the tyrosine kinase activity of FGFR3 was inhibited by the chemical inhibitor PD173074 or an siRNA knockdown strategy, the proliferation inhibition by rituximab was attenuated, indicating that FGFR3 participates in the rituximab-dependent signal transduction pathway leading to proliferation inhibition. These observations raise the possibility that concomitant targeted therapy toward FGFR3 might improve the efficacy and safety of the rituximab therapy.     

miR-20a and miR-290, multi-faceted players with a role in tumourigenesis and senescence

Expression of microRNAs changes markedly in tumours and evidence indicates that they are causatively related to tumourigenesis, behaving as tumour suppressor microRNAs or onco microRNAs; in some cases they can behave as both depending on the type of cancer. Some tumour suppressor microRNAs appear to be an integral part of the p53 and Retinoblastoma (RB) network, the main regulatory pathways controlling senescence, a major tumour suppressor mechanism. The INK4a/ARF locus which codifies for two proteins, p19ARF and p16INK4a, plays a central role in senescence by controlling both p53 and RB. Recent evidence shows that the proto-oncogene leukaemia/lymphoma related factor, a p19ARF specific repressor, is controlled by miRNAs and that miRNAs, in particular miR-20a and miR-290, are causatively involved in mouse embryo fibroblasts (MEF) senescence in culture. Intriguingly, both miR-20a, member of the oncogenic miR-17-92 cluster, and miR-290, belonging to the miR-290-295 cluster, are highly expressed in embryonic stem (ES) cells. The pro-senescence role of miR-20a and miR-290 in MEF is apparently in contrast with their proliferative role in tumour and ES cells. We propose that miRNAs may exert opposing functions depending on the miRNAs repertoire as well as target/s level/s present in different cellular contexts, suggesting the importance of evaluating miRNAs activity in diverse genetic settings before their therapeutic use as tumour suppressors.     

Cryptic organisation within an apparently irregular rostrocaudal distribution of interneurons in the embryonic zebrafish spinal cord

The molecules and mechanisms involved in patterning the dorsoventral axis of the developing vertebrate spinal cord have been investigated extensively and many are well known. Conversely, knowledge of mechanisms patterning cellular distributions along the rostrocaudal axis is relatively more restricted. Much is known about the rostrocaudal distribution of motoneurons and spinal cord cells derived from neural crest but there is little known about the rostrocaudal patterning of most of the other spinal cord neurons. Here we report data from our analyses of the distribution of dorsal longitudinal ascending (DoLA) interneurons in the developing zebrafish spinal cord. We show that, although apparently distributed irregularly, these cells have cryptic organisation. We present a novel cell-labelling technique that reveals that DoLA interneurons migrate rostrally along the dorsal longitudinal fasciculus of the spinal cord during development. This cell-labelling strategy may be useful for in vivo analysis of factors controlling neuron migration in the central nervous system. Additionally, we show that DoLA interneurons persist in the developing spinal cord for longer than previously reported. These findings illustrate the need to investigate factors and mechanisms that determine “irregular” patterns of cell distribution, particularly in the central nervous system but also in other tissues of developing embryos.     

昆虫卵黄蛋白及其激素调控的研究进展

卵黄蛋白的结构及其合成、摄取过程与激素的调控机理是目前昆虫生理学的研究热点之一。近几年,随着分子克隆技术、基因工程手段和生物信息学的发展,对卵黄蛋白基因的研究将为寻找害虫生物防治提供新途径。本文对昆虫卵黄蛋白及其激素调控进行了综述。为防治害虫再猖獗的发生和促进大量繁殖益虫提供重要的理论依据。     

The small heat shock protein 20 RSI2 interacts with and is required for stability and function of tomato resistance protein I‐2

Race‐specific disease resistance in plants depends on the presence of resistance (R) genes. Most R genes encode NB‐ARC‐LRR proteins that carry a C‐terminal leucine‐rich repeat (LRR). Of the few proteins found to interact with the LRR domain, most have proposed (co)chaperone activity. Here, we report the identification of RSI2 (Required for Stability of I‐2) as a protein that interacts with the LRR domain of the tomato R protein I‐2. RSI2 belongs to the family of small heat shock proteins (sHSPs or HSP20s). HSP20s are ATP‐independent chaperones that form oligomeric complexes with client proteins to prevent unfolding and subsequent aggregation. Silencing of RSI2‐related HSP20s in Nicotiana benthamiana compromised the hypersensitive response that is normally induced by auto‐active variants of I‐2 and Mi‐1, a second tomato R protein. As many HSP20s have chaperone properties, the involvement of RSI2 and other R protein (co)chaperones in I‐2 and Mi‐1 protein stability was examined. RSI2 silencing compromised the accumulation of full‐length I‐2 in planta, but did not affect Mi‐1 levels. Silencing of heat shock protein 90 (HSP90) and SGT1 led to an almost complete loss of full‐length I‐2 accumulation and a reduction in Mi‐1 protein levels. In contrast to SGT1 and HSP90, RSI2 silencing led to accumulation of I‐2 breakdown products. This difference suggests that RSI2 and HSP90/SGT1 chaperone the I‐2 protein using different molecular mechanisms. We conclude that I‐2 protein function requires RSI2, either through direct interaction with, and stabilization of I‐2 protein or by affecting signalling components involved in initiation of the hypersensitive response.     

Anti-CD20scFv/IgGFc/CD80/CD28/zeta转染人T淋巴细胞对原代CLL细胞的作用

目的:将已成功构建表达anti-CD20scFv/CD80/CD28/zeta转染人T淋巴细胞,体外观察该类细胞特异性清除CD20+原代慢性淋巴细胞白血病(CLL)细胞的能力,为肿瘤的过继免疫治疗提供新思路。方法:将本室成功构建的含anti-CD20scFv/IgGFc/CD80片段的PLNCX质粒,转染PA317包装细胞,挑取高滴度的包装细胞株收获逆转录病毒,用收获的病毒感染刺激分裂的人外周血T细胞,经G418筛选后与CD20+原代CLL细胞在体外共同培养,在显微镜下观察CD20+的原代CLL细胞生长状态,ELISA检测试剂盒检测T细胞分泌细胞因子的功能。结果:重组基因修饰的T细胞能在体外杀伤CD20+原代CLL细胞,而对CD20-细胞无杀伤作用;同时靶细胞为CD20+组上清液中IL-2(1301.00pg/ml)和IFN-γ(602.18pg/ml)水平与CD20-组相比明显升高。结论:嵌合锚定T细胞能够成功构建;该类T细胞在体外能特异性杀伤CD20+的原代CLL细胞。