Dados do Trabalho

Título

Targeting IGF1R/IRS signaling exhibits antineoplastic effects in multiple myeloma cells

Introdução

Multiple myeloma (MM) is a hematologic malignancy characterized by clonal proliferation of malignant plasma cells that cause hypercalcemia, anemia, osteolytic lesions, renal failure, immunosuppression, and high relapse rates. The IGF1 induces proliferation and antiapoptotic effects via the pathway PI3K/AKT and MAPK, even in IL6-independent MM models, indicating that the IGR1R/IRS1 axis plays an important role in disease development and progression. NT157 is a synthetic compound that leads to long-term inhibition of signaling IGF1R-IRS1/2.

Objetivo

In the present study, we evaluated the expression. Levels of the genes involved in the axis IGF1/IGF1R/IRS1-2 in a cohort of MM, as well as characterizing the effects of pharmacological inhibition of this pathway, with NT157, in cellular models of the disease.

Métodos

The expression data of IGF1, IGF1R, IRS1 e IRS2 were derived from the database AmaZonia! 2008. Analysis of the gene dependence score was generated for 20 distinct MM cell lines by DepMap and obtained from the MyeloDB database. The cell lines of MM, MM1.S, MM1.R, U266, and RPMI 8226, were used. Cell viability was evaluated by MTT assay, clonogenicity by colony formation assay, apoptosis by flow cytometry, and annexin V/PI and signaling pathways by Western blotting. Spearman, Mann-Whitney, or ANOVA tests were used as appropriate. P values < 0.05 were considered significant.

Resultados

IGF1 and IRS1 mRNA levels were increased in MM patients, while IGF1R and IRS2 levels were reduced (p < 0.05). A positive correlation was observed between IGF1R and IRS2 levels (r = 0.38, p = 0.03). IGF1R phosphorylation was observed in MM1.S and MM1.R, and receptor expression is also observed in RPMI 8226 cells. IRS1 expression was observed in all cell lines. IRS2 expression was observed in MM1.S, MM1.R, and RPMI 8226. The dependence score was 0.032 for IGF1, -0.519 for IGF1R, -0.503 for IRS1 and -0.455 for IRS2. Treatment with NT157 reduced the cell viability of all models evaluated in a time- and concentration-dependent manner. Concentration-dependent reduction of colony formation and induction of apoptosis in MM cells were also observed (p < 0.05). In the molecular scenario, NT157 induced markers of apoptosis (PARP1 cleavage), DNA damage (γH2AX) and cellular stress (p-ERK1/2) and reduced protein-associated proteins (p-RPS6) in MM1.S and U266. In MM1.S a reduction in phosphorylation of IGF1R, STAT3, and STAT5 was observed. IRS1 levels were reduced in U266 cells.

Conclusões

The IGF1/IGF1R/IRS signaling axis is differentially activated in MM cells, and the gene dependence analysis suggests that the presence of the receptor and intracellular adaptor proteins are more important than autocrine IGF1, probably that this can be obtained from paracrine sources. Pharmacological inhibition of IGF1R/IRS1 showed marked antineoplastic effects in MM cell models. Molecular analysis suggests a greater complexity of the action of NT157 about the repertoire of targets expressed in each cell model and deserves further investigation.

Palavras-chave

Multiple myeloma; NT157; IGF1R/IRS

Financiador do resumo

Support by FAPESP, CNPq, e CAPES.