Constitutive activation of Met (through amplification, overexpression, point mutations and chromosomal translocation) has been implicated in the development of human cancer. Met is over-expressed in a variety of carcinomas and sarcomas, is mutated in hereditary and sporadic papillary renal carcinomas, and is activated by translocation (Tpr-Met) in gastric carcinomas. Thus, Met is an appropriate target for testing innovative therapies for cancer. Recently, RNA interference has emerged as a powerful tool for gene silencing. Given the absolute specificity of target recognition by siRNAs, this could be the method of choice to specifically ablate expression of mutated or rearranged proto-oncogenes, leaving unperturbed the expression of the wild-type allele. As a first approach to suppressing oncogenic forms of Met through RNA interference we decided to target Tpr-Met, which has been found expressed in gastric carcinoma patients. We introduced in the pSUPER plasmid (under the control of the H1-RNA gene promoter), sequences which yield siRNAs complementary to various Met regions including the Tpr-Met junction (TM2). The TM2 siRNA efficiently and specifically ablates Tpr-Met expression in transfected cells. We now intend to verify the efficiency of this silencing system by infecting T lymphoma cells, derived from a transgenic model of Tpr-Met-mediated lymphomagenesis generated in the lab. Furthermore, the TM2 siRNA-producing virus will also be used to suppress growth of Tpr-Met driven xenografts in nude mice. The ultimate goal of these studies would be to adapt the system to ablate Tpr-Met expression in our animal models to obtain regression of Tpr-Met driven tumors, thus offering a proof of concept that this technology can be applied to cancer therapy.
RNAI AS A TOOL TO SUPPRESS TPR-MET MEDIATED TUMORIGENESIS
ACCORNERO, Paolo;TAULLI, Riccardo;CREPALDI, Tiziana;PONZETTO, Carola
2003-01-01
Abstract
Constitutive activation of Met (through amplification, overexpression, point mutations and chromosomal translocation) has been implicated in the development of human cancer. Met is over-expressed in a variety of carcinomas and sarcomas, is mutated in hereditary and sporadic papillary renal carcinomas, and is activated by translocation (Tpr-Met) in gastric carcinomas. Thus, Met is an appropriate target for testing innovative therapies for cancer. Recently, RNA interference has emerged as a powerful tool for gene silencing. Given the absolute specificity of target recognition by siRNAs, this could be the method of choice to specifically ablate expression of mutated or rearranged proto-oncogenes, leaving unperturbed the expression of the wild-type allele. As a first approach to suppressing oncogenic forms of Met through RNA interference we decided to target Tpr-Met, which has been found expressed in gastric carcinoma patients. We introduced in the pSUPER plasmid (under the control of the H1-RNA gene promoter), sequences which yield siRNAs complementary to various Met regions including the Tpr-Met junction (TM2). The TM2 siRNA efficiently and specifically ablates Tpr-Met expression in transfected cells. We now intend to verify the efficiency of this silencing system by infecting T lymphoma cells, derived from a transgenic model of Tpr-Met-mediated lymphomagenesis generated in the lab. Furthermore, the TM2 siRNA-producing virus will also be used to suppress growth of Tpr-Met driven xenografts in nude mice. The ultimate goal of these studies would be to adapt the system to ablate Tpr-Met expression in our animal models to obtain regression of Tpr-Met driven tumors, thus offering a proof of concept that this technology can be applied to cancer therapy.
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