Anti-MAPK4 monoclonal antibody, clone 3G5

The oncofetal RNA-binding protein IGF2BP1 (IGF2 mRNA binding protein 1) is overexpressed in a subset of cancers and promotes cell cycle, migration and aggressive phenotype by regulating post-transcriptionally a number of key mRNAs (e. g, ACTB, CD44, CTNNB1, KRAS, MAPK4, MYC, PTEN and others). IGF2BP1 is also overexpressed in t(12;21)(p13;q22)-positive acute lymphoblastic leukemia (ALL), but the biological significance of this phenomenon has not been addressed so far. We have identified leukemia fusion gene ETV6/RUNX1 mRNA to be highly enriched in immunoprecipitated fraction of endogenous IGF2BP1 from a model cell line REH and t(12;21)(p13;q22)-positive ALL samples. Furthermore, downregulation of IGF2BP1 by two-fold has resulted in a corresponding decrease of ETV6/RUNX1 mRNA validating this transcript as a target of IGF2BP1 protein in t(12;21)(p13;q22)-positive ALL. These data infer that IGF2BP1 is a potent regulator of ETV6/RUNX1 mRNA stability and potentially link this evolutionary-highly conserved protein to cell transformation events in ETV6/RUNX1-mediated leukemogenesis of t(12;21)( p13;q22)-positive ALL (C) 2015 Elsevier Inc. All rights reserved.

Multiple myeloma (MM) accounts for 10% of all hematological malignancies. Dysregulation of microRNAs (miRNAs) or long non-coding RNAs (lncRNAs) has important impacts on progression of MM. Circular RNAs (circRNAs) are correlated with malignancy in the modulation of tumor progression. This study aims to investigate the effect of circ_0000190 on regulating the progression of MM. Microscopic examination via single molecule fluorescent in situ hybridization indicates the location of circ_0000190. qRT-PCR and Western blot were used to evaluate the expression of RNAs and proteins. Potential target of circ_0000190 was searched as miRNA, and examined by luciferase reporter assay. A computational screen was also conducted to search the potential target of miRNA. In vitro cell viability, proliferation, apoptosis assays and flow cytometric were performed to assess the effects of circ_0000190 and its target on MM. Mice model of human MM was established with subcutaneous xenograft tumor, qRT-PCR and western blot were performed to detect the underlying mechanisms of circ_0000190 on MM. Circ_0000190 was located in the cytoplasm, and down-regulated in both bone marrow tissue and peripheral blood, while the target of circ_0000190, miR-767-5p, was up-regulated, suggesting a negative correlation between them. The binding ability between circ_0000190 and miR-767-5p was confirmed by luciferase reporter assay. Moreover, circ_0000190 inhibited cell viability, proliferation and induced apoptosis of MM thus inhibiting cell progression, which is partially through the negative regulation of miR-767-5p. Mitogen-activated protein kinase 4 (MAPK4) is a direct target of miR-767-5p. In addition, over-expression of miR-767-5p promoted cell progression by directly targeting and regulating MAPK4. The MM model mice with administration of circ_0000190 suppressed tumor growth and progression. Our results revealed that the ability of circ_0000190 to protect against MM was inherited through repression of miR-767-5p, and miR-767-5p might be a tumor drive through targeting MAPK4. Therefore, a novel role of circ_0000190 on regulating the progression of MM was found, and the clinical application of circRNAs might represent a strategy in MM.