PIM3 Proto-Oncogene Kinase Is a Common Transcriptional Target of Divergent EWS/ETS Oncoproteins

Abstract

Despite significant structural diversity, present evidence suggests that EWS/ETS fusion proteins promote oncogenesis by transcriptionally modulating a common set of target genes. In order to identify these genes, microarray expression analyses were performed on NIH 3T3 polyclonal populations expressing one of three EWS/ETS fusion genes. The majority of these genes can be grouped into seven functional categories, including cellular metabolism and signal transduction. The biologic significance of these target genes was pursued. The effects of modulating genes involved in metabolism were assessed by flux studies and demonstrated shifts in glucose utilization and lactate production as a result of EWS/FLI1 expression. The proto-oncogene coding for serine/threonine kinase PIM3 was found to one of several genes encoding signal transduction proteins that were up-regulated by EWS/ETS fusions. PIM3 was found to be expressed in a panel of human Ewing's family tumor cell lines. Forced expression of PIM3 promoted anchorage-independent growth. Coexpression of a kinase-deficient PIM3 mutant attenuated EWS/FLI1-mediated NIH 3T3 tumorigenesis in immunodeficent mice.The EWS/ETS fusions comprise a group of structurally related oncoproteins that are found specifically in Ewing's family tumors (EFTs). The oncogenes coding for these oncoproteins are the result of chromosomal translocations that fuse a portion of the amino-terminal region of EWS to one of five members of the ETS family of transcription factors: FLI1, ERG, FEV, ETV1, and E1AF (for review, see reference 1). While ETS proteins have been extensively studied, the normal functions of EWS are still coming to light. EWS is part of a family of putative RNA binding proteins that also includes TLS and TAF II 68. A growing body of evidence suggests that members of this family (the TET family) may be involved in multiple levels of mRNA metabolism, from roles as transport chaperones to splicing factors (6,9,32,34,35). Interestingly, each of these three TET members is involved in tumor-associated chromosomal translocations associated with various human sarcomas, including desmoplastic small round cell tumor and clear cell sarcoma (3,11,17,21,25,26). In all cases, these translocations lead to the expression of chimeric proteins analogous to EWS/ETS fusions by incorporating DNA-binding domains (DBDs) from different transcription factors. Tumor histologies appear to correlate with the specific DBDs rather than the particular TET component in these fusions.All members of the ets-coded family of transcription factors contain a conserved 85-amino-acid domain that mediates sitespecific DNA binding at target gene promoters and enhancers (for review, see reference 16). Based on the primary amino acid sequences of their respective ets DBDs, the five EWS/ETS fusions can be partitioned into two groups. Group 1 contains EWS/FLI1, EWS/ERG, and EWS/FEV, and its members display up to 98% amino acid identity between their DBDs (FLI1 versus ERG). Similarly, in group 2, the ETV1 and E1AF DBDs are iden...

Inducible Expression of Chimeric EWS/ETS Proteins Confers Ewing's Family Tumor-Like Phenotypes to Human Mesenchymal Progenitor Cells

“…The major steps in the development of EFT should be commonly regulated by distinct chimeric EWS/ETS proteins. Indeed, several genes are common transcriptional targets of different chimeric EWS/ETS proteins in the murine system (11,24,35). Our data also showed that the 642 probes are coregulated in both EWS/FLI1-expressing cells and EWS/ ERG-expressing cells.…”

Aberrant Expression of Pim-3 Promotes Proliferation and Migration of Ovarian Cancer Cells

“…The inhibition of Pim-3 by shRNA also reduced endothelial cell spreading, vascular tube formation, and migration of prostate cancer (Nakano et al, 2012). Pim-3 can be regulated by the Ets family of transcription factors in NIH3T3 cells and human Ewing's sarcoma cells (Deneen et al, 2003). Later studies showed that Pim-3 is activated by the Ets-1 transcription factor in pancreatic cancer cells (Li et al, 2009).…”

A Novel Regulatory Mechanism of Pim-3 Kinase Stability and Its Involvement in Pancreatic Cancer Progression

“…Later, KID-1 was renamed Pim-3 because of its high sequence similarity with Pim family proteins, which belong to the group of calcium/calmodulin-regulated kinase (1). Subsequently, Deneen and colleagues demonstrated that Pim-3 gene transcription was enhanced in EWS/ETS-induced malignant transformation of NIH3T3 cells (2), suggesting the involvement of Pim-3 in tumorigenesis. In line with these observations, we demonstrated that Pim-3 expression was enhanced in malignant lesions, but not normal tissues of endoderm-derived organs such as the liver (3), pancreas (4), colon (5), and stomach (6).…”