Rabbit Anti-Human HSPH1 (a.a. 508-858) Polyclonal antibody

The pituitary melanotrope cells of the amphibian Xenopus laevis are responsible for the production of the pigment-dispersing peptide alpha-melanophore-stimulating hormone, which allows the animal to adapt its skin color to its environment. During adaptation to a dark background the melanotrope cells undergo remarkable changes characterized by dramatic increases in cell size and secretory activity. In this study we performed microarray mRNA expression profiling to identify genes important to melanotrope activation and growth. We show a strong increase in the expression of the immediate early gene (IEG) c-Fos and of the brain-derived neurotrophic factor gene (BDNF). Furthermore, we demonstrate the involvement of another IEG in the adaptation process, Nur77, and conclude from in vitro experiments that the expression of both c-Fos and Nur77 are partially regulated by the adenylyl cyclase system and calcium ions. In addition, we found a steady up-regulation of Ras-like product during the adaptation process, possibly evoked by BDNF/TrkB signaling. Finally, the gene encoding the 105-kDa heat shock protein HSPh1 was transiently up-regulated in the course of black-background adaptation and a gene product homologous to ferritin (ferritin-like product) was > 100-fold up-regulated in fully black-adapted animals. We suggest that these latter two genes are induced in response to cellular stress and that they may be involved in changing the mode of mRNA translation required to meet the increased demand for de novo protein synthesis. Together, our results show that microarray analysis is a valuable approach to identify the genes responsible for generating coordinated responses in physiologically activated cells. J. Cell. Physiol. 227: 288-296, 2012. (C) 2011 Wiley Periodicals, Inc.

We have shown that human B-cell non-Hodgkin lymphomas (B-NHLs) express heat shock protein (HSP) H1/105 in function of their aggressiveness. Here, we now clarify its role as a functional B-NHL target by testing the hypothesis that it promotes the stabilization of key lymphoma oncoproteins. HSPH1 silencing in 4 models of aggressive B-NHLs was paralleled by Bcl-6 and c-Myc downregulation. In vitro and in vivo analysis of HSPH1-silenced Namalwa cells showed that this effect was associated with a significant growth delay and the loss of tumorigenicity when 10 4 cells were injected into mice. Interestingly, we found that HSPH1 physically interacts with c-Myc and Bcl-6 in both Namalwa cells and primary aggressive B-NHLs. Accordingly, expression of HSPH1 and either c-Myc or Bcl-6 positively correlated in these diseases. Our study indicates that HSPH1 concurrently favors the expression of 2 key lymphoma oncoproteins, thus confirming its candidacy as a valuable therapeutic target of aggressive B-NHLs.