Interferon regulatory factor 8 (IRF8) is a transcription factor that plays a critical role in normal hematopoiesis, such that disruption of IRF8 activity promotes leukemogenesis. We and others have identified aberrant expression of IRF8 transcripts, including novel splice variants, in acute myeloid leukemia (AML), but studies have not investigated the prognostic significance of these transcripts. Therefore, we developed and optimized quantitative expression assays for both, the wild type, or the reference sequence (WT-IRF8) and novel splice variants (SV-IRF8). These assays were used to quantify IRF8 transcript levels in 194 adult patients with AML, and multivariate analyses investigated the prognostic significance of these expression levels. After adjusting for known prognostic factors, expression levels of WT- or SV-IRF8 transcripts were not significantly associated with complete responses or overall survival. However, increased expression of WT-IRF8 was associated with decreased relapse-free survival (RFS) in both univariate (P = 0.010) and multivariate (P = 0.019) analyses. Similarly, increased expression of SV-IRF8 was associated with a decreased RFS (univariate, P = 0.026 and multivariate, P = 0.021). These studies show for the first time that WT-IRF8 and SV-IRF8 are independent adverse prognostic factors for patients with AML. Additional studies are planned to examine the prognostic significance of IRF8 transcripts in other populations of AML patients.
References
[1]
Schmidt M, Bies J, Tamura T, Ozato K, Wolff L (2004) The interferon regulatory factor ICSBP/IRF-8 in combination with PU.1 up-regulates expression of tumor suppressor p15(Ink4b) in murine myeloid cells. Blood 103: 4142–4149.
[2]
Zhu C, Saberwal G, Lu Y, Platanias LC, Eklund EA (2004) The interferon consensus sequence-binding protein activates transcription of the gene encoding neurofibromin 1. J Biol Chem 279: 50874–50885.
[3]
Tsujimura H, Nagamura-Inoue T, Tamura T, Ozato K (2002) IFN consensus sequence binding protein/IFN regulatory factor-8 guides bone marrow progenitor cells toward the macrophage lineage. J Immunol 169: 1261–1269.
[4]
Tamura T, Thotakura P, Tanaka TS, Ko MS, Ozato K (2005) Identification of target genes and a unique cis element regulated by IRF-8 in developing macrophages. Blood 106: 1938–1947.
[5]
Becker AM, Michael DG, Satpathy AT, Sciammas R, Singh H, et al. (2012) IRF-8 extinguishes neutrophil production and promotes dendritic cell lineage commitment in both myeloid and lymphoid mouse progenitors. Blood 119: 2003–2012.
[6]
Holtschke T, Lohler J, Kanno Y, Fehr T, Giese N, et al. (1996) Immunodeficiency and chronic myelogenous leukemia-like syndrome in mice with a targeted mutation of the ICSBP gene. Cell 87: 307–317.
[7]
Schwieger M, Lohler J, Friel J, Scheller M, Horak I, et al. (2002) AML1-ETO inhibits maturation of multiple lymphohematopoietic lineages and induces myeloblast transformation in synergy with ICSBP deficiency. J Exp Med 196: 1227–1240.
[8]
Turcotte K, Gauthier S, Tuite A, Mullick A, Malo D, et al. (2005) A mutation in the Icsbp1 gene causes susceptibility to infection and a chronic myeloid leukemia-like syndrome in BXH-2 mice. J Exp Med 201: 881–890.
[9]
Diaz-Blanco E, Bruns I, Neumann F, Fischer JC, Graef T, et al. (2007) Molecular signature of CD34(+) hematopoietic stem and progenitor cells of patients with CML in chronic phase. Leukemia 21: 494–504.
[10]
Schmidt M, Hochhaus A, Nitsche A, Hehlmann R, Neubauer A (2001) Expression of nuclear transcription factor interferon consensus sequence binding protein in chronic myeloid leukemia correlates with pretreatment risk features and cytogenetic response to interferon-alpha. Blood 97: 3648–3650.
[11]
Lee KY, Geng H, Ng KM, Yu J, van Hasselt A, et al.. (2008) Epigenetic disruption of interferon-gamma response through silencing the tumor suppressor interferon regulatory factor 8 in nasopharyngeal, esophageal and multiple other carcinomas. Oncogene.
[12]
Silva FP, Swagemakers SM, Erpelinck-Verschueren C, Wouters BJ, Delwel R, et al. (2009) Gene expression profiling of minimally differentiated acute myeloid leukemia: M0 is a distinct entity subdivided by RUNX1 mutation status. Blood 114: 3001–3007.
[13]
Schmidt M, Nagel S, Proba J, Thiede C, Ritter M, et al. (1998) Lack of interferon consensus sequence binding protein (ICSBP) transcripts in human myeloid leukemias. Blood 91: 22–29.
[14]
Qian Z, Fernald AA, Godley LA, Larson RA, Le Beau MM (2002) Expression profiling of CD34+ hematopoietic stem/ progenitor cells reveals distinct subtypes of therapy-related acute myeloid leukemia. Proc Natl Acad Sci U S A 99: 14925–14930.
[15]
Stirewalt DL, Choi YE, Sharpless NE, Pogosova-Agadjanyan EL, Cronk MR, et al.. (2009) Decreased IRF8 expression found in aging hematopoietic progenitor/stem cells. Leukemia 23: 391–393. PMCID: PMC2640437.
[16]
Anderson JE, Kopecky KJ, Willman CL, Head D, O'Donnell MR, et al. (2002) Outcome after induction chemotherapy for older patients with acute myeloid leukemia is not improved with mitoxantrone and etoposide compared to cytarabine and daunorubicin: a Southwest Oncology Group study. Blood 100: 3869–3876.
[17]
Petersdorf SH, Rankin C, Head DR, Terebelo HR, Willman CL, et al. (2007) Phase II evaluation of an intensified induction therapy with standard daunomycin and cytarabine followed by high dose cytarabine for adults with previously untreated acute myeloid leukemia: a Southwest Oncology Group study (SWOG-9500). Am J Hematol 82: 1056–1062.
[18]
Godwin JE, Kopecky KJ, Head DR, Willman CL, Leith CP, et al. (1998) A double-blind placebo-controlled trial of granulocyte colony-stimulating factor in elderly patients with previously untreated acute myeloid leukemia: a Southwest oncology group study (9031). Blood 91: 3607–3615.
[19]
List AF, Kopecky KJ, Willman CL, Head DR, Persons DL, et al. (2001) Benefit of cyclosporine modulation of drug resistance in patients with poor-risk acute myeloid leukemia: a Southwest Oncology Group study. Blood 98: 3212–3220.
[20]
Stirewalt DL, Kopecky KJ, Meshinchi S, Appelbaum FR, Slovak ML, et al. (2001) FLT3, RAS, and TP53 mutations in elderly patients with acute myeloid leukemia. Blood 97: 3589–3595.
[21]
Stirewalt DL, Kopecky KJ, Meshinchi S, Engel JH, Pogosova-Agadjanyan EL, et al. (2006) Size of FLT3 internal tandem duplication has prognostic significance in patients with acute myeloid leukemia. Blood 107: 3724–3726.
[22]
Ostronoff F, Othus M, Ho PA, Kutny M, Geraghty DE, et al.. (2012) Mutations in the DNMT3A exon 23 independently predict poor outcome in older patients with acute myeloid leukemia: a SWOG report. Leukemia.
[23]
Stirewalt DL, Meshinchi S, Kopecky KJ, Fan W, Pogosova-Agadjanyan EL, et al. (2008) Identification of genes with abnormal expression changes in acute myeloid leukemia. Genes Chromosomes Cancer 47: 8–20.
[24]
Livak KJ, Schmittgen TD (2001) Analysis of relative gene expression data using real-time quantitative PCR and the 2(-Delta Delta C(T)) Method. Methods 25: 402–408.
[25]
Scheller M, Foerster J, Heyworth CM, Waring JF, Lohler J, et al. (1999) Altered development and cytokine responses of myeloid progenitors in the absence of transcription factor, interferon consensus sequence binding protein. Blood 94: 3764–3771.
[26]
Tamura T, Nagamura-Inoue T, Shmeltzer Z, Kuwata T, Ozato K (2000) ICSBP directs bipotential myeloid progenitor cells to differentiate into mature macrophages. Immunity 13: 155–165.
[27]
Tsujimura H, Tamura T, Gongora C, Aliberti J, Reis e Sousa C, et al. (2003) ICSBP/IRF-8 retrovirus transduction rescues dendritic cell development in vitro. Blood 101: 961–969.
[28]
Lucioni M, Novara F, Fiandrino G, Riboni R, Fanoni D, et al. (2011) Twenty-one cases of blastic plasmacytoid dendritic cell neoplasm: focus on biallelic locus 9p21.3 deletion. Blood 118: 4591–4594.
[29]
Yang D, Thangaraju M, Greeneltch K, Browning DD, Schoenlein PV, et al. (2007) Repression of IFN regulatory factor 8 by DNA methylation is a molecular determinant of apoptotic resistance and metastatic phenotype in metastatic tumor cells. Cancer Res 67: 3301–3309.
