Functional effect of point mutations in the α-folate receptor gene of CABA I ovarian carcinoma cells

Fabio Mangiarotti, Silvia Miotti, Enrico Galmozzi, Mimma Mazzi, Sabrina Sforzini, Silvana Canevari, Antonella Tomassetti

Research output: Contribution to journalArticle

Abstract

The α-folate receptor (αFR) is overexpressed in 90% of nonmucinous ovarian carcinomas. In addition to the known role of αFR binding and mediating the internalization of folates, functional interaction of αFR with signaling molecules was recently shown. To identify a model to study the role of αFR in ovarian carcinoma, we characterized the αFR gene in the ovarian carcinoma cell line CABA I in comparison to a reference line, IGROV1. In CABA I cells, Northern blot analysis revealed an αFR transcript of the expected length and FACS analysis indicated receptor expression on the cell membrane; however, RNase protection assay revealed no specific signals. Southern blot and genomic PCR analysis suggested the presence of a rearrangement(s) involving the 5′ region of the gene in CABA I cells as compared to IGROV1 cells. Cloning and sequencing of CABA I αFR cDNA revealed several point mutations. The partitioning of αFR in membrane microdomains from CABA I cells and its association with regulatory molecules was comparable to that of IGROV1 cells. By contrast, the αFR expressed on the CABA I cell membrane bound folic acid with lower affinity, and ectopic expression of the corresponding cDNA in CHO cells confirmed impaired folic acid binding. Thus, CABA I cells may provide a tool to delineate functional domains of the αFR.

Original languageEnglish
Pages (from-to)488-498
Number of pages11
JournalJournal of Cellular Biochemistry
Volume81
Issue number3
DOIs
Publication statusPublished - 2001

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Keywords

  • α-folate receptor
  • Folic acid binding
  • Genetic rearrangement
  • Ovarian carcinoma
  • Triton-insoluble domain

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology

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