TY - JOUR
T1 - Development and characterization of a conditionally immortalized human osteoblastic cell line stably transfected with the human androgen receptor gene
AU - Hofbauer, Lorenz C.
AU - Hicok, Kevin C.
AU - Schroeder, Marcy J.
AU - Harris, Steven A.
AU - Robinson, John A.
AU - Khosla, Sundeep
PY - 1997/9/15
Y1 - 1997/9/15
N2 - Androgens have significant beneficial effects on the skeleton. However, studies on the effects of androgens on osteoblasts are limited due to the absence of appropriate model systems that combine completness of the osteoblastic phenotype, rapid proliferation rate, and stable expression of the androgen receptor (AR). Thus, we stably transfected the conditionally immortalized human fetal osteoblastic cell line (hFOB) with the human wild- type AR (hAR) cDNA. Compared to nontransfected hFOB cells, constitutive hAR mRNA expression in three independent hAR-transfected hFOB clones (hFOB/AR) was 15-fold higher in hFOB/AR-16, 62-fold higher in hFOB/AR-2, and 72-fold higher in hFOB/AR-6 cells, respectively, as assessed by semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR). Detectable constitutive levels of hAR mRNA by Northern blot analysis were present in hFOB/AR-2 and hFOB/AR-6 cells, but not in hFOB/AR-16 or hFOB cells, respectively. Treatment with 5α-dihydrotestosterone (5α-DHT) (10-8 M) for 24 h did not alter hAR mRNA steady state levels in the hFOB/AR cell lines. Nuclear binding studies demonstrated 152 ± 73 (mean ± SEM) functional hARs/nucleus in non-transfected hFOB cells, 3,940 ± 395 functional hARs/nucleus in hFO/AR-2 cells, and 3,987 ±+ 823 hARs/nucleus in hFOB/AR-6 cells, respectively. Treatment with 5α-DHT increased the expression of a transiently transfected androgen response element-chloramphenicol acetyltransferase (ARE-CAT) reporter construct in hFOB/AR-6 cells in a dose- and time-dependent manner; no such effect was observed in transiently transfected hFOB cells lacking exogenously transfected hARs. Moreover, 5α- DHT-induced ARE-CAT expression was inhibited by the selective androgen receptor antagonist, hydroxyflutamide. In summary, we have developed and characterized androgen-responsive osteoblastic cell lines derived from normal human fetal bone that express physiological levels of functional hARs. These cell lines should provide a suitable model for further studies on the effects of androgens on osteoblast function, including the identification of potential androgen-regulated growth factors and cytokines.
AB - Androgens have significant beneficial effects on the skeleton. However, studies on the effects of androgens on osteoblasts are limited due to the absence of appropriate model systems that combine completness of the osteoblastic phenotype, rapid proliferation rate, and stable expression of the androgen receptor (AR). Thus, we stably transfected the conditionally immortalized human fetal osteoblastic cell line (hFOB) with the human wild- type AR (hAR) cDNA. Compared to nontransfected hFOB cells, constitutive hAR mRNA expression in three independent hAR-transfected hFOB clones (hFOB/AR) was 15-fold higher in hFOB/AR-16, 62-fold higher in hFOB/AR-2, and 72-fold higher in hFOB/AR-6 cells, respectively, as assessed by semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR). Detectable constitutive levels of hAR mRNA by Northern blot analysis were present in hFOB/AR-2 and hFOB/AR-6 cells, but not in hFOB/AR-16 or hFOB cells, respectively. Treatment with 5α-dihydrotestosterone (5α-DHT) (10-8 M) for 24 h did not alter hAR mRNA steady state levels in the hFOB/AR cell lines. Nuclear binding studies demonstrated 152 ± 73 (mean ± SEM) functional hARs/nucleus in non-transfected hFOB cells, 3,940 ± 395 functional hARs/nucleus in hFO/AR-2 cells, and 3,987 ±+ 823 hARs/nucleus in hFOB/AR-6 cells, respectively. Treatment with 5α-DHT increased the expression of a transiently transfected androgen response element-chloramphenicol acetyltransferase (ARE-CAT) reporter construct in hFOB/AR-6 cells in a dose- and time-dependent manner; no such effect was observed in transiently transfected hFOB cells lacking exogenously transfected hARs. Moreover, 5α- DHT-induced ARE-CAT expression was inhibited by the selective androgen receptor antagonist, hydroxyflutamide. In summary, we have developed and characterized androgen-responsive osteoblastic cell lines derived from normal human fetal bone that express physiological levels of functional hARs. These cell lines should provide a suitable model for further studies on the effects of androgens on osteoblast function, including the identification of potential androgen-regulated growth factors and cytokines.
KW - Androgen receptor
KW - Androgens
KW - Bone cells
KW - Dehydroepiandrosterone
KW - Dihydrotestosterone
KW - Hydroxyflutamide
KW - Osteoblasts
KW - Stable transfection
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U2 - 10.1002/(SICI)1097-4644(19970915)66:4<542::AID-JCB13>3.0.CO;2-D
DO - 10.1002/(SICI)1097-4644(19970915)66:4<542::AID-JCB13>3.0.CO;2-D
M3 - Article
C2 - 9282332
AN - SCOPUS:0030879496
SN - 0730-2312
VL - 66
SP - 542
EP - 551
JO - Journal of cellular biochemistry
JF - Journal of cellular biochemistry
IS - 4
ER -