Missense polymorphism (C/T224) in the human cathepsin D pro-fragment determined by polymerase chain reaction--single strand conformational polymorphism analysis and possible consequences in cancer cells.
Overexpression of cathepsin D in human breast cancers is associated with a higher risk of relapse and metastasis. Also, pro-enzyme routing is altered in several tumoral mammary cell lines, leading to its hypersecretion. MCF7 cells compared to normal kidney carry a C-->T transition at position 224 in the cathepsin D gene which converts Ala to valine in its pro-fragment. Using polymerase chain reaction-single strand conformational polymorphism analysis (PCR-SSCP), the variant T allele frequency was found to be 23-30%, and equally distributed in cancer and normal cells. Six to nine per cent of genotypes were homozygous T/T, 34-41% were heterozygous T/C and 50-59% were homozygous C/C. Moreover, genotypes were identical in 19 out of 20 matched sets of tumoral mammary cells and normal white blood cells from the same patients. Loss of heterozygosity was noted in 1 case. C/T224 transition is thus not due to a somatic event. However, this missense polymorphism might modify procathepsin D secretion and/or maturation in breast cancer cells.
Touitou
I
I
Unité Hormones et Cancer (U148) INSERM, University of Montpellier 1, Department of Cell Biology, France.
Capony
F
F
Brouillet
J P
JP
Rochefort
H
H
D000483:Alleles; D001483:Base Sequence; D001943:Breast Neoplasms / Q000201:enzymology / Q000235:genetics*; D002402:Cathepsin D / Q000096:biosynthesis / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic / Q000235:genetics*; D014407:Tumor Cells, Cultured
D002402:Cathepsin D