Pasquini G M F, Davey R A M, Ho P W M, Michelangeli V P, Grill V, Kaczmarczyk S J, Zajac J D
Department of Medicine, University of Melbourne, Royal Melbourne Hospital, Victoria, Australia.
Bone. 2002 Nov;31(5):598-605. doi: 10.1016/s8756-3282(02)00872-4.
Parathyroid hormone-related protein (PTHrP) has been implicated as being important in the growth of tumor cells responsive to the peptide. We utilized a rat osteoblastic osteosarcoma cell line, UMR 106-01, which has PTHrP receptors and a PTHrP-responsive adenylate cyclase/cAMP messenger system, to produce a modified cell line that overexpresses PTHrP. The human PTHrP cDNA sequence was transfected by electroporation into UMR 106-01 cells and the stable cell lines UMR-36 and UMR-34 were established. The modified cell line, UMR-36, had increased levels of PTHrP mRNA compared with control cell lines and secreted PTHrP into the culture medium at levels of 0.01-0.1 pmol/10(7) cells in 12 h. The secreted peptide was biologically active as indicated by its ability to activate adenylate cyclase. The number of UMR-36 cells following 9 days in culture was reduced by up to 80% compared with control lines, which was associated with decreased (3)H-thymidine incorporation into genomic DNA. Addition of 1000-fold excess of the PTHrP antagonist, PTHrP(7-34), to UMR-36 cells resulted in the escape of growth inhibition and increased rate of growth. In vivo, tumors derived from UMR-36 cells were smaller in size compared with tumors derived from control cells. In conclusion, increased autocrine secretion of, and responsiveness to, PTHrP results in inhibited growth kinetics of an osteoblast-like bone tumor cell line in vitro and in vivo.
甲状旁腺激素相关蛋白（PTHrP）被认为在对该肽有反应的肿瘤细胞生长中起重要作用。我们利用一种大鼠成骨细胞骨肉瘤细胞系UMR 106 - 01，其具有PTHrP受体和PTHrP反应性腺苷酸环化酶/cAMP信使系统，来产生一种过表达PTHrP的改良细胞系。通过电穿孔将人PTHrP cDNA序列转染到UMR 106 - 01细胞中，并建立了稳定细胞系UMR - 36和UMR - 34。与对照细胞系相比，改良细胞系UMR - 36的PTHrP mRNA水平升高，并在12小时内以0.01 - 0.1 pmol/10(7)细胞的水平将PTHrP分泌到培养基中。分泌的肽具有生物活性，这可通过其激活腺苷酸环化酶的能力来表明。培养9天后，UMR - 36细胞的数量与对照系相比减少了多达80%，这与基因组DNA中(3)H - 胸苷掺入减少有关。向UMR - 36细胞中添加1000倍过量的PTHrP拮抗剂PTHrP(7 - 34)导致生长抑制解除且生长速率增加。在体内，源自UMR - 36细胞的肿瘤与源自对照细胞的肿瘤相比尺寸较小。总之，PTHrP自分泌分泌增加及其反应性增加导致体外和体内成骨样骨肿瘤细胞系的生长动力学受到抑制。
