Approximately 50% of prostate cancer (PCa) cases are characterized by the over-expression of a truncated form of the ETS Related Gene (ERG), a member of the ETS transcription factor family. High abundance of ERG mRNA is mainly due to the fusion of the 5'-untranslated sequence of TMPRSS2(21q22.3) and ERG coding region(21q22.2). Chromosomal translocations involving ERG have also been linked to other tumours, such as Ewing sarcoma and myeloid leukemia, where the fusion proteins EWS/ERG and FUS/ERG have been described. Moreover, wild-type (wt)ERG is over-expressed in acute myeloid leukemia patients. Despite the frequency of ERG rearrangements in PCa, different groups showed that transgenic TMPRSS2/ERG mice did not develop cancer. In order to improve our understanding of the role of the TMPRSS2/ERG translocation in PCa, we compared the activity of TMPRSS2/ERG to the other ERG fusions in a homogeneous cellular context. We transfected the fibroblast cell line NIH3T3 with wt-ERG, EWS/ERG, FUS/ERG and the truncated ERG cDNA derived from the TMPRSS2/ERG fusion. To ensure reliable results, three independent stable transfectants for each ERG form were analysed. Compared to control cells, all the populations show high expression of the exogenous gene and changes at the morphological level, with increased cellular thickening and disorganized cells motion. Proliferation assays indicate that only FUS/ERG and EWS/ERG lead to a significant increase in the proliferative potential compared to control cells (FUS/ERG p*=0.012; EWS/ERG p*=0.025; TMPRSS2/ERG p=0.140; wtERG p=0.064), while no significant differences in survival were observed in low serum conditions. Furthermore, soft agar assays showed that none of the ERG forms is able to induce colony formation. Gene expression profiling of all transfectants evaluated with Affymetrix-Genechip® Mouse Gene 1.0ST Array revealed that all the ERG forms display a common deregulation of genes expressed in endothelial cells compared to the control, as expected from published results supporting the involvement of ERG in endothelial cell differentiation. NIH3T3 cells expressing wtERG protein showed the greatest similarity to TMPRSS2/ERG transfectants, with the latter having a stronger influence on invasion/motility programs and transcriptional regulation (DAVID tools). Typically, an oncogene can provide one or more of three main features to the cancer cell: a growth advantage, increased survival, or genetic instability. The last is a prerequisite for rapid and disordered growth, as it permits the accumulation of advantageous mutations. Since TMPRSS2/ERG seems not able to provide a growth advantage or increased survival, we evaluated its influence on genetic instability. Our preliminary data suggest that TMPRSS2/ERG is able to alter the cellular response to DNA damaging agents and the experimental results will be presented at the meeting. These finding advance the possibility for a role of TMPRSS2/ERG in genetic instability.
Magistroni, V., Sanselicio, S., Mologni, L., Reid, J., Gariboldi, M., GAMBACORTI PASSERINI, C. (2009). Role of TMPRSS2/ERG in cellular transformation. Intervento presentato a: SOCIETA' ITALIANA DI CANCEROLOGIA, SESTO SAN GIOVANNI.
Role of TMPRSS2/ERG in cellular transformation
MAGISTRONI, VERA;MOLOGNI, LUCA;GAMBACORTI PASSERINI, CARLO
2009
Abstract
Approximately 50% of prostate cancer (PCa) cases are characterized by the over-expression of a truncated form of the ETS Related Gene (ERG), a member of the ETS transcription factor family. High abundance of ERG mRNA is mainly due to the fusion of the 5'-untranslated sequence of TMPRSS2(21q22.3) and ERG coding region(21q22.2). Chromosomal translocations involving ERG have also been linked to other tumours, such as Ewing sarcoma and myeloid leukemia, where the fusion proteins EWS/ERG and FUS/ERG have been described. Moreover, wild-type (wt)ERG is over-expressed in acute myeloid leukemia patients. Despite the frequency of ERG rearrangements in PCa, different groups showed that transgenic TMPRSS2/ERG mice did not develop cancer. In order to improve our understanding of the role of the TMPRSS2/ERG translocation in PCa, we compared the activity of TMPRSS2/ERG to the other ERG fusions in a homogeneous cellular context. We transfected the fibroblast cell line NIH3T3 with wt-ERG, EWS/ERG, FUS/ERG and the truncated ERG cDNA derived from the TMPRSS2/ERG fusion. To ensure reliable results, three independent stable transfectants for each ERG form were analysed. Compared to control cells, all the populations show high expression of the exogenous gene and changes at the morphological level, with increased cellular thickening and disorganized cells motion. Proliferation assays indicate that only FUS/ERG and EWS/ERG lead to a significant increase in the proliferative potential compared to control cells (FUS/ERG p*=0.012; EWS/ERG p*=0.025; TMPRSS2/ERG p=0.140; wtERG p=0.064), while no significant differences in survival were observed in low serum conditions. Furthermore, soft agar assays showed that none of the ERG forms is able to induce colony formation. Gene expression profiling of all transfectants evaluated with Affymetrix-Genechip® Mouse Gene 1.0ST Array revealed that all the ERG forms display a common deregulation of genes expressed in endothelial cells compared to the control, as expected from published results supporting the involvement of ERG in endothelial cell differentiation. NIH3T3 cells expressing wtERG protein showed the greatest similarity to TMPRSS2/ERG transfectants, with the latter having a stronger influence on invasion/motility programs and transcriptional regulation (DAVID tools). Typically, an oncogene can provide one or more of three main features to the cancer cell: a growth advantage, increased survival, or genetic instability. The last is a prerequisite for rapid and disordered growth, as it permits the accumulation of advantageous mutations. Since TMPRSS2/ERG seems not able to provide a growth advantage or increased survival, we evaluated its influence on genetic instability. Our preliminary data suggest that TMPRSS2/ERG is able to alter the cellular response to DNA damaging agents and the experimental results will be presented at the meeting. These finding advance the possibility for a role of TMPRSS2/ERG in genetic instability.
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