This gene encodes a member of the runt domain-containing family of transcription factors. A heterodimer of this protein and a beta subunit forms a complex that binds to the core DNA sequence 5'-YGYGGT-3' found in a number of enhancers and promoters,[2] and can either activate or suppress transcription. It also interacts with other transcription factors. It functions as a tumor suppressor, and the gene is frequently deleted or transcriptionally silenced in cancer. Multiple transcript variants encoding different isoforms have been found for this gene.[3]
In melanocytic cells RUNX3 gene expression may be regulated by MITF.[4]
Knockout mouse
Runx3 null mouse gastric mucosa exhibits hyperplasia due to stimulated proliferation and suppressed apoptosis in epithelial cells, and the cells are resistant to TGF-beta stimulation.[5]
The RUNX3 controversy
In 2011 serious doubt was cast over the tumor suppressor function of Runx3 originated from the earlier publication by Li and co-workers.[6]
On the basis of the original study by Li and co-workers (2002), the majority of later literature citing Li and co-workers (2002) assumed that RUNX3 was expressed in the normal gut epithelium and that it is therefore likely to act as a tumor suppressor in the particular epithelial cancer investigated. Most of this literature used RUNX3 promoter methylation status in various cancers as a proxy for its expression. However, quite many genes are known to be methylated in tumor cell genomes, and the majority of these genes are not expressed in the normal tissue of origin of these cancers. Others used poorly characterized (or fully invalidated) antibodies to detect the RUNX3 protein, or used RT-PCR or validated antibodies and failed to detect RUNX3 in the gut epithelium but still did not question the original finding by Li and co-workers (2002). This facts have recently been discussed in a novel by Ülo Maiväli.[7]
↑Levanon D, Negreanu V, Bernstein Y, Bar-Am I, Avivi L, Groner Y (Sep 1994). "AML1, AML2, and AML3, the human members of the runt domain gene-family: cDNA structure, expression, and chromosomal localization". Genomics. 23 (2): 425–32. doi:10.1006/geno.1994.1519. PMID7835892.
Vogiatzi P, De Falco G, Claudio PP, Giordano A (Apr 2006). "How does the human RUNX3 gene induce apoptosis in gastric cancer? Latest data, reflections and reactions". Cancer Biology & Therapy. 5 (4): 371–4. doi:10.4161/cbt.5.4.2748. PMID16627973.
Wijmenga C, Speck NA, Dracopoli NC, Hofker MH, Liu P, Collins FS (Apr 1995). "Identification of a new murine runt domain-containing gene, Cbfa3, and localization of the human homolog, CBFA3, to chromosome 1p35-pter". Genomics. 26 (3): 611–4. doi:10.1016/0888-7543(95)80185-O. PMID7607690.
Bae SC, Takahashi E, Zhang YW, Ogawa E, Shigesada K, Namba Y, Satake M, Ito Y (Jul 1995). "Cloning, mapping and expression of PEBP2 alpha C, a third gene encoding the mammalian Runt domain". Gene. 159 (2): 245–8. doi:10.1016/0378-1119(95)00060-J. PMID7622058.
Bae SC, Yamaguchi-Iwai Y, Ogawa E, Maruyama M, Inuzuka M, Kagoshima H, Shigesada K, Satake M, Ito Y (Mar 1993). "Isolation of PEBP2 alpha B cDNA representing the mouse homolog of human acute myeloid leukemia gene, AML1". Oncogene. 8 (3): 809–14. PMID8437866.
Bangsow C, Rubins N, Glusman G, Bernstein Y, Negreanu V, Goldenberg D, Lotem J, Ben-Asher E, Lancet D, Levanon D, Groner Y (Nov 2001). "The RUNX3 gene--sequence, structure and regulated expression". Gene. 279 (2): 221–32. doi:10.1016/S0378-1119(01)00760-0. PMID11733147.
Waki T, Tamura G, Sato M, Terashima M, Nishizuka S, Motoyama T (Apr 2003). "Promoter methylation status of DAP-kinase and RUNX3 genes in neoplastic and non-neoplastic gastric epithelia". Cancer Science. 94 (4): 360–4. doi:10.1111/j.1349-7006.2003.tb01447.x. PMID12824905.
Puig-Kröger A, Sanchez-Elsner T, Ruiz N, Andreu EJ, Prosper F, Jensen UB, Gil J, Erickson P, Drabkin H, Groner Y, Corbi AL (Nov 2003). "RUNX/AML and C/EBP factors regulate CD11a integrin expression in myeloid cells through overlapping regulatory elements". Blood. 102 (9): 3252–61. doi:10.1182/blood-2003-02-0618. PMID12855590.
Li QL, Kim HR, Kim WJ, Choi JK, Lee YH, Kim HM, Li LS, Kim H, Chang J, Ito Y, Youl Lee K, Bae SC (Jan 2004). "Transcriptional silencing of the RUNX3 gene by CpG hypermethylation is associated with lung cancer". Biochemical and Biophysical Research Communications. 314 (1): 223–8. doi:10.1016/j.bbrc.2003.12.079. PMID14715269.
Xiao WH, Liu WW (Feb 2004). "Hemizygous deletion and hypermethylation of RUNX3 gene in hepatocellular carcinoma". World Journal of Gastroenterology. 10 (3): 376–80. doi:10.3748/wjg.v10.i3.376. PMID14760761.
Oshimo Y, Oue N, Mitani Y, Nakayama H, Kitadai Y, Yoshida K, Ito Y, Chayama K, Yasui W (2004). "Frequent loss of RUNX3 expression by promoter hypermethylation in gastric carcinoma". Pathobiology. 71 (3): 137–43. doi:10.1159/000076468. PMID15051926.
Jin YH, Jeon EJ, Li QL, Lee YH, Choi JK, Kim WJ, Lee KY, Bae SC (Jul 2004). "Transforming growth factor-beta stimulates p300-dependent RUNX3 acetylation, which inhibits ubiquitination-mediated degradation". The Journal of Biological Chemistry. 279 (28): 29409–17. doi:10.1074/jbc.M313120200. PMID15138260.
Ku JL, Kang SB, Shin YK, Kang HC, Hong SH, Kim IJ, Shin JH, Han IO, Park JG (Sep 2004). "Promoter hypermethylation downregulates RUNX3 gene expression in colorectal cancer cell lines". Oncogene. 23 (40): 6736–42. doi:10.1038/sj.onc.1207731. PMID15273736.
Sakakura C, Hagiwara A, Miyagawa K, Nakashima S, Yoshikawa T, Kin S, Nakase Y, Ito K, Yamagishi H, Yazumi S, Chiba T, Ito Y (Jan 2005). "Frequent downregulation of the runt domain transcription factors RUNX1, RUNX3 and their cofactor CBFB in gastric cancer". International Journal of Cancer. 113 (2): 221–8. doi:10.1002/ijc.20551. PMID15386419.
1io4: CRYSTAL STRUCTURE OF RUNX-1/AML1/CBFALPHA RUNT DOMAIN-CBFBETA CORE DOMAIN HETERODIMER AND C/EBPBETA BZIP HOMODIMER BOUND TO A DNA FRAGMENT FROM THE CSF-1R PROMOTER