Pichierri P.,Unit of Experimental Carcinogenesis |
Bignami M.,Unit of Experimental Carcinogenesis
Drug Discovery Today: Disease Models | Year: 2012
Mismatch repair (MMR) is the major repair pathway for removal of errors occurring during replication, which is often inactive in human tumours. Because MMR can control the cellular response to the cytotoxic effects of some DNA damaging drugs, here we will discuss how theMMRstatus can influence the biological response to chemotherapy. In addition we illustrate how some features of MMR-defective tumours might be exploited for personalized therapy treatments. © 2011 Elsevier Ltd. All rights reserved.
Molatore S.,University of Pavia |
Russo M.T.,Unit of Experimental Carcinogenesis |
D'Agostino V.G.,University of Pavia |
Barone F.,Unit of Experimental Carcinogenesis |
And 7 more authors.
Human Mutation | Year: 2010
MUTYH-associated polyposis (MAP) is a colorectal cancer syndrome, due to biallelic mutations of MUTYH. This Base Excision Repair gene encodes for a DNA glycosylase that specifically mitigates the high mutagenic potential of the 8-hydroxyguanine (8-oxodG) along the DNA. Aim of this study was to characterize the biological effects, in a mammalian cell background, of human MUTYH mutations identified in MAP patients (137insIW [c.411-416dupATGGAT; p.137insIleTrp]; R171W [c.511C>T; p.Arg171Trp]; E466del [c.1395-1397delGGA; p.Glu466del]; Y165C [c.494A>G; p.Tyr165Cys]; and G382D [c.1145G>A; p.Gly382Asp]). We set up a novel assay in which the human proteins were expressed in Mutyh -/- mouse defective cells. Several parameters, including accumulation of 8-oxodG in the genome and hypersensitivity to oxidative stress, were then used to evaluate the consequences of MUTYH expression. Human proteins were also obtained from Escherichia coli and their glycosylase activity was tested in vitro. The cell-based analysis demonstrated that all MUTYH variants we investigated were dysfunctional in Base Excision Repair. In vitro data complemented the in vivo observations, with the exception of the G382D mutant, which showed a glycosylase activity very similar to the wild-type protein. Our cell-based assay can provide useful information on the significance of MUTYH variants, improving molecular diagnosis and genetic counseling in families with mutations of uncertain pathogenicity. © 2009 Wiley-Liss, Inc.