Pim-1 and Pim-2 kinases are required for efficient pre-B-cell transformation by v-Abl oncogene.
The precise mechanisms by which Abl oncogenes transform hematopoietic cells are unknown. We have examined the role of Pim kinases in v-Abl-mediated transformation. In v-Abl transformants, expression of Pim-1 and Pim-2, but not Pim-3, is dependent on Abl kinase activity. Transformation assays demonstrate that v-Abl cannot efficiently transform bone marrow cells derived from Pim-1(-/-)/Pim-2(-/-) mice. Ectopic expression of either Pim-1 or Pim-2 in Pim-1(-/-)/Pim-2(-/-) cells restores transformation by v-Abl, strongly suggesting that either Pim-1 or Pim-2 is required for v-Abl-mediated tumorigenesis. Interestingly, the combined deficiency of Pim-1, Pim-2, and Suppressor of Cytokine Signalling (SOCS)-1 resulted in partial restoration of v-Abl transformation efficiency. In addition, Pim kinases are involved in modification of SOCS-1 and in regulating SOCS-1 protein levels in v-Abl-transformed cells. Furthermore, Pim kinases regulate the proapoptotic proteins Bcl-XS and BAD. Pim kinases inhibit the expression of Bcl-XS. Pim deficiency decreases the phosphorylation levels of BAD, whereas ectopic expression of Pim-1 increases the amount of phospho-BAD. This correlates with an increased protection from apoptosis in Abl transformants expressing Pim kinases. Together, these data suggest that Pim kinases play a key role in the v-Abl transformation, possibly via participating in modulation of SOCS-1 and via regulating the apoptotic signaling.
Chen
Ji-Long
JL
Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.
Limnander
Andre
A
Rothman
Paul B
PB
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001402:B-Lymphocytes / Q000166:cytology* / Q000378:metabolism*; D001549:Benzamides; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D000068877:Imatinib Mesylate; D008099:Liver / Q000166:cytology / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D016374:Oncogene Proteins v-abl / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D010879:Piperazines / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D051573:Proto-Oncogene Proteins c-pim-1 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D011743:Pyrimidines / Q000494:pharmacology; D000071222:Suppressor of Cytokine Signaling 1 Protein; D050826:Suppressor of Cytokine Signaling Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D051025:bcl-Associated Death Protein / Q000378:metabolism
D001549:Benzamides; D016374:Oncogene Proteins v-abl; C094167:Pim2 protein, mouse; D010879:Piperazines; D011518:Proto-Oncogene Proteins; D011743:Pyrimidines; C491590:Socs1 protein, mouse; D000071222:Suppressor of Cytokine Signaling 1 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D051025:bcl-Associated Death Protein; D000068877:Imatinib Mesylate; D017346:Protein Serine-Threonine Kinases; D051573:Proto-Oncogene Proteins c-pim-1