Cell Cycle Regulator GeneCDC5L, a Potential Target for 6p12-p21 Amplicon in Osteosarcoma

Abstract

Osteosarcoma is a primary malignant tumor of bone arising from primitive bone-forming mesenchymal cells and accounts for f60% of malignant bone tumors. Our comparative genomic hybridization (CGH) studies have identified frequent amplification at 6p12-p21, 12q13-q15, and 17p11.2 in osteosarcoma. Of these amplified regions, 6p12-p21 is particularly interesting because of its association with progression and poor prognosis in patients with osteosarcoma. In an attempt to identify aberrantly expressed gene(s) mapping to the 6p12-p21 amplicon, a region-specific array was generated using 108 overlapping BAC and P1 clones covering a 28.8-Mb region at 0.26-Mb intervals. Based on array CGH analysis, the 6p amplicon was refined to 7.9 Mb between the clones RP11-91E11 and RP1-244F2 and 10 amplified clones, with possible target genes, were identified. To study the expression pattern of the target genes from the hotspot amplicon and known candidate genes from 6p12-21, we did quantitative reverse transcription-PCR analysis of MAPK14, MAPK13, CDKN1A, PIM1, MDGA1, BTB9, DNAH8, CCND3, PTK7, CDC5L, and RUNX2 on osteosarcoma patient samples and seven cell lines. The combined array CGH and quantitative reverse transcription-PCR analysis identified amplification and overexpression of CDC5L, CCND3, and RUNX2. We screened these three genes for protein expression by Western blotting and immunohistochemistry and detected overexpression of CDC5L. Furthermore, we used an in vivo assay to show that CDC5L possesses potential oncogenic activity. These results indicate that CDC5L, a cell cycle regulator important for the G 2 -M transition, is the most likely candidate oncogene for the 6p12-p21 amplicon found in osteosarcoma. (Mol Cancer Res 2008;6(6):937 -46)

Genomic Alterations and Allelic Imbalances Are Strong Prognostic Predictors in Osteosarcoma

“…The most commonly amplified genomic interval of 6p21-p23 harbors, among others, several candidate genes: angiogenesis-associated VEGFA, cell cycle-associated E2F3, CCND3, and RUNX2, and carcinomaassociated PTK7. These genes are directly or indirectly involved in the pathogenesis and pathways of malignant tumors, and amplifications have also been described in a high percentage of osteosarcomas (4,11,12,17,(37)(38)(39). In the present study, we found high amplification spots in 24% of the investigated tumors (Fig.…”

“…There is not a single amplicon covering the whole central region of 6p; instead we found a few smaller hot spot regions harboring CCND3, RUNX2, and VEGFA. These genes have already been found to be overexpressed in osteosarcomas (38), and high expression of VEGFA has been correlated with a poor prognosis (40,41). Interestingly, the cell-cycle-associated E2F3, a downstream target of RB1, which has been found amplified and overexpressed in other tumors, e.g., in urothelial cancer (42), was the only gene located within a small amplified spot suggesting an alternative way to interfere with the RB1 pathway.…”

Expression of Human MDGA1 Increases Cell Motility and Cell-Cell Adhesion and Reduces Adhesion to Extracellular Matrix Proteins in MDCK Cells

“…MDGA1 has been proposed as a new schizophrenia susceptibility gene involved in neuronal migration [35], meanwhile MDGA2 has been postulated as a novel autism susceptibility gene that shows a high similarity to contactin 4 (CNTN4), which has also been linked to this disease [36]. Moreover, MDGA1 expression has been found to be altered in tumor tissues [3,37]. Future studies to investigate the implication of the MDGAs in these human diseases should be promising.…”

Analysis of Segmental Duplications, Mouse Genome Synteny and Recurrent Cancer-Associated Amplicons in Human Chromosome 6p21–p12

“…Most importantly, gain of 6p is associated with advanced stages of cancer [Seute et al, 2001;Chochi et al, 2009], metastasis [Tanami et al, 2005], tumor cell proliferation [Tomovska et al, 2001], and poor event-free survival [Lu et al, 2008]. When one considers rearrangements across the entire genome, gain and/or amplification of the region 6p21-p12 is one of the most frequent aberrations in solid tumors and hematologic cancers [Baudis and Cleary, 2001].…”

“…In human osteosarcomas, recurrent amplification at chromosome 6p21-p12 has been documented [Lau et al, 2004;Lu et al, 2008;Selvarajah et al, 2008;Sadikovic et al, 2009] and has recently been shown to be associated with clinical response [Sadikovic et al, in press]. Gain and amplification of murine chromosomal regions homologous to human chromosome 6p are also reported in conditional mouse models of osteosarcoma [Walkley et al, 2008].…”