jte-607 and Leukemia--Myeloid--Acute

The post-genomic era has seen many advances in our understanding of cancer pathways, yet resistance and tumor heterogeneity necessitate multiple approaches to target even monogenic tumors. Here, we combine phenotypic screening with chemical genetics to identify pre-messenger RNA endonuclease cleavage and polyadenylation specificity factor 3 (CPSF3) as the target of JTE-607, a small molecule with previously unknown target. We show that CPSF3 represents a synthetic lethal node in a subset of acute myeloid leukemia (AML) and Ewing's sarcoma cancer cell lines. Inhibition of CPSF3 by JTE-607 alters expression of known downstream effectors in AML and Ewing's sarcoma lines, upregulates apoptosis and causes tumor-selective stasis in mouse xenografts. Mechanistically, it prevents the release of newly synthesized pre-mRNAs, resulting in read-through transcription and the formation of DNA-RNA hybrid R-loop structures. This study implicates pre-mRNA processing, and specifically CPSF3, as a druggable target providing an avenue to therapeutic intervention in cancer.

Topics: Animals; Apoptosis; Binding Sites; Carboxylic Ester Hydrolases; Cell Line, Tumor; Cell Survival; Cleavage And Polyadenylation Specificity Factor; HEK293 Cells; Humans; Leukemia, Myeloid, Acute; Male; Mass Spectrometry; Mice; Mice, Inbred C57BL; Neoplasm Transplantation; Phenotype; Phenylalanine; Piperazines; Protein Binding; RNA Precursors; RNA, Messenger; RNA, Small Interfering; Sarcoma, Ewing

Proinflammatory cytokines and growth factors have been thought to play crucial roles in the pathology of acute myelogenous leukemia (AML) by supporting the proliferation and survival of AML cells in an autocrine and paracrine manner, although further elucidation is required. JTE-607 was originally identified as a multiple cytokine inhibitor that suppresses production of proinflammatory cytokines from lipopolysaccharide (LPS)-stimulated peripheral blood mononuclear cells. Herein, we report that JTE-607 exhibits inhibitory activity on the growth of AML cell lines accompanying reduction of the proinflammatory cytokine and growth factor production. In in vitro studies, JTE-607 suppressed expression and production of cytokines, which are spontaneously up-regulated in AML cell lines. JTE-607 also abrogated proliferation of AML cells in a concentration range in which colony formation of normal bone marrow cells was not affected. The growth inhibition by JTE-607 was characterized by induction of cell-cycle arrest at the S-phase and apoptosis, accompanied by a decrease in c-Myc and increase in p21(waf1/cip1). In a leukemia model engrafted with U-937 cells, JTE-607 significantly prolonged survival in mice and reduced human cytokine mRNA levels in the bone marrow. These results suggest the usefulness of JTE-607 in therapeutic applications for patients with hypercytokinemia and aggressive AML cell proliferation.

Topics: Animals; Apoptosis; Cell Line, Tumor; Cell Proliferation; Cyclin-Dependent Kinase Inhibitor p21; Cytokines; Female; Humans; Leukemia, Myeloid, Acute; Mice; Mice, SCID; Phenylalanine; Piperazines; Vascular Endothelial Growth Factor A

Accumulating findings suggest that in acute myeloid leukemia (AML) patients, proinflammatory cytokines and growth factors play important roles in the proliferation and survival of AML cells in an autocrine and paracrine manner, leading to deterioration of AML. JTE-607 is a multiple cytokine inhibitor that potently suppresses production of proinflammatory cytokines. In the present study, we investigated the potency of JTE-607 as an antileukemic agent by exploiting a SCID mouse acute leukemia model.. SCID mice injected with anti-asialo-GM1 antibody were exposed to sublethal total-body irradiation at a dose of 3 Gy and then inoculated intravenously with AML cells. JTE-607 was administered using osmotic minipumps. The effects of JTE-607 on mouse survival time, human interleukin (IL)-8 levels in mouse plasma, and proportion of human CD45(+) cells in the bone marrow were studied.. The survival time of the mice was strictly dependent on the number of U-937 cells proliferating in vivo. Administration of JTE-607 during the initial 7 days significantly prolonged survival of the mice, suggesting killing activity of JTE-607 against AML cells in vivo. Delayed administration of JTE-607 also prolonged the survival of mice bearing established leukemia with an effect comparable to the maximum tolerable dose of cytarabine. Flow cytometer analysis of bone marrow cells revealed decreased number of human CD45(+) cells. Human IL-8 level was also reduced by JTE-607.. Our results indicate that JTE-607 has potential to be a new class of antileukemic drug that exerts inhibitory activities against both the proliferation and proinflammatory cytokine production of AML cells.

Topics: Animals; Autocrine Communication; Cell Proliferation; Cytokines; Disease Models, Animal; Drug Evaluation, Preclinical; Female; Humans; Interleukin-8; Leukemia, Myeloid, Acute; Leukocyte Common Antigens; Mice; Mice, SCID; Neoplasm Transplantation; Neoplasms, Experimental; Paracrine Communication; Phenylalanine; Piperazines; Transplantation, Heterologous