Whitlatch Lyman W, Young Michael V, Schwartz Gary G, Flanagan John N, Burnstein Kerry L, Lokeshwar Bal L, Rich Edwin S, Holick Michael F, Chen Tai C
Department of Medicine, Vitamin D, Skin and Bone Research Laboratory, Endocrine Section, Boston University School of Medicine, Boston, MA 02118, USA.
J Steroid Biochem Mol Biol. 2002 Jun;81(2):135-40. doi: 10.1016/s0960-0760(02)00053-5.
The hormone 1alpha,25-dihydroxyvitamin D (1alpha,25(OH)(2)D) inhibits growth and induces differentiation of prostate cells. The enzyme responsible for 1alpha,25(OH)(2)D synthesis, 25-hydroxyvitamin D (25(OH)D)-1alpha-hydroxylase (1alpha-OHase), has been demonstrated in human prostate cells. We compared the levels of 1alpha-OHase activity in prostate cancer cell lines, LNCaP, DU145 and PC-3 and in primary cultures of normal, cancerous and benign prostatic hyperplasia (BPH) prostate cells. We observed a marked decrease in 1alpha-OHase activity in prostate cancer cells, including an undetectable level of activity in LNCaP cells. Transient or stable transfection of 1alpha-OHase cDNA into LNCaP cells increased 1alpha-OHase activity from undetectable to 4.95pmole/mg+/-0.69pmole/mg and 5.8pmole/mg+/-0.7pmole/mg protein per hour, respectively. In response to 25(OH)D, the prohormone of 1alpha,25(OH)(2)D, the transfected LNCaP cells showed a significant inhibition of 3H-thymidine incorporation (37%+/-6% and 56%+/-4% at 10(-8)M for transiently and stably transfected cells, respectively). These findings support an important autocrine role for 1alpha,25(OH)(2)D in the prostate and suggest that the re-introduction of the 1alpha-OHase gene to prostate cancer cells, in conjunction with the systemic administration of 25(OH)D, constitutes an endocrine form of gene therapy that may be less toxic than the systemic administration of 1alpha,25(OH)(2)D.
激素1α,25 - 二羟基维生素D（1α,25(OH)₂D）可抑制前列腺细胞生长并诱导其分化。负责合成1α,25(OH)₂D的酶，即25 - 羟基维生素D（25(OH)D）-1α - 羟化酶（1α - OHase），已在人前列腺细胞中得到证实。我们比较了前列腺癌细胞系LNCaP、DU145和PC - 3以及正常、癌性和良性前列腺增生（BPH）前列腺细胞原代培养物中1α - OHase的活性水平。我们观察到前列腺癌细胞中1α - OHase活性显著降低，包括LNCaP细胞中无法检测到活性水平。将1α - OHase cDNA瞬时或稳定转染到LNCaP细胞中，使1α - OHase活性分别从无法检测到增加到每小时4.95皮摩尔/毫克±0.69皮摩尔/毫克和5.8皮摩尔/毫克±0.7皮摩尔/毫克蛋白质。响应1α,25(OH)₂D的前体激素25(OH)D，转染的LNCaP细胞显示出³H - 胸腺嘧啶核苷掺入的显著抑制（瞬时转染和稳定转染细胞在10⁻⁸M时分别为37%±6%和56%±4%）。这些发现支持1α,25(OH)₂D在前列腺中具有重要的自分泌作用，并表明将1α - OHase基因重新引入前列腺癌细胞，结合全身给予25(OH)D，构成一种内分泌形式的基因治疗，其毒性可能比全身给予1α,25(OH)₂D小。
