Isolation and Characterization of PAGE-1 andGAGE-7

Abstract

The LNCaP progression model of human prostate cancer consists of lineage-related sublines that differ in their androgen sensitivity and metastatic potential. A differential display polymerase chain reaction was employed to evaluate mRNA expression differences between the LNCaP sublines in order to define the differences in gene expression between the androgensensitive, nontumorigenic LNCaP cell line and the androgen-insensitive, metastatic LNCaP sublines, C4-2 and C4-2B. An amplicon, BG16.21, was isolated that showed increased expression in the androgen-independent and metastatic LNCaP sublines, C4-2 and C4-2B. Hybridization screening of a gt11 expression library with BG16.21 revealed two transcripts, both homologous to BG16.21 at the 3 end. A GenBank TM data base search using the GCG Wisconsin software package revealed the shorter ϳ600-bp transcript (designated GAGE-7) to be a new member of the GAGE family. The second ϳ700-bp transcript was a novel gene (designated PAGE-1, "prostate associated gene") with only 45% homology to GAGE gene family members. RNA blot analysis demonstrated that GAGE-7 mRNA was expressed at equal levels in all lineage related prostate cancer cell sublines, while PAGE-1 mRNA levels were elevated 5-fold in C4-2 and C4-2B as compared with LNCaP cells. Neither GAGE-7 nor PAGE-1 demonstrated any regulation by androgens in the prostate cancer cell lines used in this study. PAGE-1 and GAGE-7 expression was found to be restricted to testes (high) and placenta (low) on human multiple tissue Northern blots. As GAGE/MAGE antigens were reported previously to be targets for tumor-specific cytotoxic lymphocytes in melanoma, these results suggest that PAGE-1 and GAGE-7 may be related to prostate cancer progression and may serve as potential targets for novel therapies.An experimental model system to study advanced and metastatic prostate cancer has been developed based on the observation that nontumorigenic bone or prostate fibroblasts, when co-inoculated with the nontumorigenic, prostate-specific antigen (PSA) 1 -secreting cell line LNCaP, induced prostate adenocarcinoma growth in vivo in nude mice (1, 2). By manipulating the androgen status of the hosts, the laboratory was able to generate various LNCaP sublines from the primary tumors (3, 4). The direct lineage-related sublines C4, C4 -2, and C4 -2B4 share cytogenetic markers and HLA haplotype with parental LNCaP, but otherwise possess distinct biologic and biochemical profiles. Most importantly, the sublines exhibit progressive tumorigenicity, metastatic potential, and androgen independence. C4, the first subline derived from LNCaP, forms tumors in intact nude mice without the need for a co-inoculum of bone fibroblasts or Matrigel®; while growth in castrated hosts still requires a co-inducer. C4-2 is a subline derived from C4, which is highly tumorigenic in intact or castrated nude mice without a co-inducer. C4-2B4 is a bone metastatic subline derived from orthotopic injection of C4-2 and has demonstrated an increased aggressiveness as compared wi...

Epigenomic Stress Response

“…It is interesting to note that expression of the GAGE antigen family has been associated with poor prognosis in some cancers. G antigen 7 is expressed in prostate cancer (43), and G antigen 7c was proposed to be an antiapoptotic gene (57). Similarly, MAGE expression is associated with metastasis (53,54).…”

Characterization of Intrinsically Disordered Prostate Associated Gene (PAGE5) at Single Residue Resolution by NMR Spectroscopy

“…Interestingly, cancer cell resistance to chemo- and radio-therapies, has been associated to the anti-apoptotic features of GAGE7 [13]. There are six different PAGE proteins (PAGE1, 2, 2B, 3, 4, and 5) [11], [14], [15], expressed in prostate or testis and also in several cancer cells. PAGE5 has been recognized as potential marker for diagnosis of specific cancers as increased expression levels are observed in melanoma, renal and lung cancer cells [4], [16], [17].…”

Identification of methylation-silenced genes in colorectal cancer cell lines: Genomic screening using oligonucleotide arrays

“…A computer-based screening strategy identified GAGE7 as a member of the GAGE family of melanoma-associated tumor antigens [26]. Expression analysis of human prostate cancer cell lines with the LNCaP progression model did not show any relationship between GAGE7 and tumor progression [26]. With regard to PAGE-5, VCX, and MAEL, the regulation and function of these genes in human cancer is currently uncharacterized.…”

“…The biologic functions associated with methylation-mediated transcriptional silencing of the GAGED2 gene are not clear. A computer-based screening strategy identified GAGE7 as a member of the GAGE family of melanoma-associated tumor antigens [26]. Expression analysis of human prostate cancer cell lines with the LNCaP progression model did not show any relationship between GAGE7 and tumor progression [26].…”