Basic Research on Peptide Analogs

本研究以人卵巢上皮癌细胞系HTOA为研究对象，观察了促黄体生成素释放激素（LHRH）和生长抑素（SS）等多肽类似物对人卵巢癌和子宫内膜癌生长的影响，以及LHRH类似物对大鼠卵巢卵泡发育的影响。LHRH激动剂（布舍瑞林）和拮抗剂（SB-75）剂量依赖性地抑制HTOA肿瘤在无胸腺裸鼠中的生长。LHRH类似物通过细胞凋亡和干扰EGF受体磷酸化直接抑制HTOA细胞增殖。在人子宫内膜癌细胞系HEC-1中检测到生长抑素高亲和力结合位点和生长抑素受体mRNA。生长抑素类似物（RC-160）在体内外也能抑制HEC-1细胞的生长。RC-160可抑制HEC-1细胞EGF受体的磷酸化，但不诱导细胞凋亡，LHRH类似物可通过细胞凋亡直接抑制颗粒细胞的增殖，而不影响EGF受体的磷酸化。在雌激素引发的垂体切除的未成年雌性大鼠，LHRH和LHRH受体的mRNA在卵巢颗粒细胞的非放射性原位杂交检测。LHRH激动剂降低卵泡生长，增加闭锁卵泡。相反，当局部LHRH被LHRH拮抗剂阻断时，卵泡生长得到促进，直径小于200 μ m的次级和三级卵泡闭锁的发生率显著降低。这些结果支持内源性LHRH参与未成熟卵泡闭锁的可能性。

In this study, we investigated (1) the effect of various peptide analogs, especialy analogs of luteinizing hormone releasing hormone (LHRH) and somatostatin, on the growth of human ovarian cancer or endometrial cancer and (2) the effect of LHRH analogs on rat ovarian follicle development.High-affinity LHRH binding sites and mRNA for LHRH receptor were detected in HTOA human epithelial ovarian cancer cell line. LHRH agonist (buserelin) and antagonist (SB-75) inhibited the growth of HTOA tumors xenografted in athymic nude mice dose-dependently. LHRH analogs directly inhibited the proliferation of HTOA cells through apoptosis and interference with EGF receptor phosphorylation. High-affinity somatostatin binding sites and mRNA for somatostatin receptor were detected in HEC-1 human endometrial cancer cell line. Somatostatin analog (RC-160) also inhibited the growth of HEC-1 cells in vivo and in vitro. RC-160 suppressed EGF receptor phosphorylation, but did not induce apoptosis in HEC-1 cells.LHRH analogs directly inhibited the proliferation of rat granulosa cells through apoptosis without interference with EGF receptor phosphorylation. In estrogen-primed hypophysectomized immature female rats, mRNA for LHRH and LHRH receptor was detected in ovarian granulosa cells by non-radioactive in situ hybridization. LHRH agonist decreased follicular growth and increased atretic follicles. In contrast, when local LHRH was blocked by administration of LHRH antagonist, follicular growth was promoted and incidence of atresia was significantly decreased in secondary and tertiary follicles less than 200mum in diameter. These results support that the possibility that endogenous LHRH is involved in atresia of immature follicles.