ABSTRACT
All-trans retinoic acid (ATRA) is a revolutionary agent for acute promyelocytic leukemia (APL) treatment via differentiation induction. However, ATRA treatment also increases cytokine, chemokine, and adhesive molecule (mainly ICAM-1) expression, which can cause clinical complications, including a severe situation known as differentiation syndrome (DS) which can cause death. Therefore, it is of clinical significance to find a strategy to specifically blunt inflammatory effects while preserving differentiation. Here we report that the natural compound, celastrol, could effectively block lung infiltrations in DS animal models created by loading ATRA-induced APL cell line NB4. In ATRA-treated NB4 cells, celastrol could potently inhibit ICAM-1 elevation and partially reduce TNF-α and IL-1ß secretion, though treatment showed no effects on IL-8 and MCP-1 levels. Celastrol's effect on ICAM-1 in ATRA-treated NB4 was related to reducing MEK1/ERK1 activation. Strikingly and encouragingly, celastrol showed no obvious effects on ATRA-induced NB4 differentiation, as determined by morphology, enzymes, and surface markers. Our results show that celastrol is a promising and unique agent for managing the side effects of ATRA application on APL, and suggest that hyper-inflammatory ability is accompanied by, but not necessary for, APL differentiation. Thus we offered an encouraging novel strategy to further improve differentiation therapy.
Subject(s)
Cell Differentiation/drug effects , Leukemia, Promyelocytic, Acute/drug therapy , Lung/drug effects , Tretinoin/adverse effects , Triterpenes/pharmacology , Animals , Cell Line, Tumor , Humans , Intercellular Adhesion Molecule-1/genetics , Intercellular Adhesion Molecule-1/metabolism , Leukemia, Promyelocytic, Acute/metabolism , Leukemia, Promyelocytic, Acute/pathology , Lung/metabolism , Lung/pathology , MAP Kinase Signaling System/drug effects , Male , Mice , Mice, Inbred NOD , Mice, SCID , Pentacyclic Triterpenes , RNA, Messenger/genetics , RNA, Messenger/metabolism , RNA, Neoplasm/genetics , RNA, Neoplasm/metabolism , Syndrome , Tretinoin/therapeutic use , Tumor Necrosis Factor-alpha/metabolismABSTRACT
We identified a novel ubiquitin-like molecule DULP from human dendritic cells. DULP contains a domain that shares 26% identity and 34% similarity with ubiquitin, and it possesses the corresponding Ile-44 hydrophobic patch used by mono- or poly-ubiquitin to interact with a ubiquitin-interaction motif (UIM) or ubiquitin-associated domain (UBA). Lysine residue corresponding to 6 of ubiquitin, which is involved in the formation of a multi-ubiquitin chain that can bind proteasomal subunit Rpn10/S5a, is also conserved in its ubiquitin-homology domain. However, DULP does not possess the highly conserved C-terminus Gly-Gly required for ubiquitin conjugation or the Lys-48 required for the formation of polyubiquitin chain to target substrates for degradation, suggesting it might be a novel ubiquitin-domain protein (UDP). DULP was found widely expressed in many cells and the ubiquitin-homology domain was not cleaved. We also confirmed that DULP expression was enriched in the nucleus and much weaker in the cytosol. Besides, we found that overexpression of DULP in 293T cells induced apoptosis, which might not be associated with the mitochondrial or proteasome pathway, with the specific mechanism remaining unclear. Further investigations are needed to identify the precise biological functions of DULP.
Subject(s)
Apoptosis , Dendritic Cells/metabolism , Ubiquitin/metabolism , Ubiquitins/metabolism , Amino Acid Sequence , Base Sequence , Cell Line, Tumor , Cell Nucleus/metabolism , Cloning, Molecular , Cytosol/metabolism , Humans , Molecular Sequence Data , Sequence Alignment , Ubiquitin/chemistry , Ubiquitins/chemistry , Ubiquitins/geneticsABSTRACT
AIM:To obtain human and murine cDNAs encoding IFN-gamma inducible protein 10 (IP-10) and cytokine responsive gene-2 (Crg-2).METHODS:The encoding genes of IP-10 and Crg-2 were amplified by RT-PCR from cultured human fibroblast cells and Balb/c mouse liver treated by IFN-gamma and TNF-alpha,respectively, and cloned into plasmids of pUC19 and pGEM3Zf(+).RESULTS:The nucleotide sequences of the amplified DNA were confirmed by endonucleases digestion and sequencing.CONCLUSION:Recombinant IP-10/crg-2 gene clones with 306bp and 314bp inserts were established for further research on biological activities and ligands of hIP-10/mCrg-2.
