The emergence of protocadherin-PC expression during the acquisition of apoptosis-resistance by prostate cancer cells.
In order to identify gene products associated with the development of acquired therapeutic resistance by prostate cancer cells, we created two novel apoptosis-resistant prostate cancer cell lines, LNCaP-TR (phorbol-ester [TPA]-Resistant) and LNCaP-SSR (Serum Starvation-Resistant) by repeated transient exposure of cultured human LNCaP cells to apoptotic stimuli followed by expansion of surviving cell populations. These cell lines were found to be cross-resistant to the alternative selective agent and also hormone-resistant when xenografted into castrated male immunodeficient mice. RNA from the LNCaP-TR line was comparatively screened using a subtractive hybridization-PCR procedure. This allowed us to identify a 249 bp cDNA fragment that hybridized to a 4.8 kb mRNA preferentially expressed by the apoptosis-resistant cells. Using RACE procedures, we cloned and sequenced the complete 4.8 kb cDNA. It is an unusual member of the protocadherin gene family containing two large overlapping open reading frames encoding homologous polypeptides, one having a signal sequence and the other lacking a signal sequence and we refer to it as protocadherin-PC. LNCaP cells directly transformed with protocadherin-PC cDNA were comparatively resistant to phorbol-ester induced apoptosis. Antibody recognition studies demonstrating the cytoplasmic nature of the protcadherin-PC translation product and its propensity to bind beta-catenin suggest that it might influence the apoptotic sensitivity of prostate cancer cells through a unique mechanism.
Chen
Min-Wei
MW
The Department of Urology, The College of Physicians and Surgeons of Columbia University, New York, NY 10032, USA.
Vacherot
Francis
F
De La Taille
Alexandre
A
Gil-Diez-De-Medina
Sixtina
S
Shen
Ruoqian
R
Friedman
Richard A
RA
Burchardt
Martin
M
Chopin
Dominique K
DK
Buttyan
Ralph
R
D000230:Adenocarcinoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D000595:Amino Acid Sequence; D000728:Androgens; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics*; D001483:Base Sequence; D015820:Cadherins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D003001:Cloning, Molecular; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D003593:Cytoplasm / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D004351:Drug Resistance; D005784:Gene Amplification; D015972:Gene Expression Regulation, Neoplastic; D005796:Genes; D006801:Humans; D008297:Male; D051379:Mice; D008819:Mice, Nude; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D009368:Neoplasm Transplantation; D009376:Neoplasms, Hormone-Dependent / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D016366:Open Reading Frames; D010455:Peptides / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D010641:Phenotype; D011471:Prostatic Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D014176:Protein Biosynthesis; D021382:Protein Sorting Signals / Q000235:genetics; D000091363:Protocadherins; D013382:Subtraction Technique; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D000728:Androgens; D015820:Cadherins; D016895:Culture Media, Serum-Free; D018076:DNA, Complementary; D009363:Neoplasm Proteins; C468654:PCDH11Y protein, human; D010455:Peptides; D021382:Protein Sorting Signals; D000091363:Protocadherins; D013755:Tetradecanoylphorbol Acetate