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Functional effect of point mutations in the α‐folate receptor gene of CABA I ovarian carcinoma cells
Author(s) -
Mangiarotti Fabio,
Miotti Silvia,
Galmozzi Enrico,
Mazzi Mimma,
Sforzini Sabrina,
Canevari Silvana,
Tomassetti Antonella
Publication year - 2001
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/1097-4644(20010601)81:3<488::aid-jcb1062>3.0.co;2-4
Subject(s) - folate receptor , microbiology and biotechnology , biology , northern blot , complementary dna , cell culture , gene , genetics , cancer cell , cancer
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. J. Cell. Biochem. 81:488–498, 2001. © 2001 Wiley‐Liss, Inc.