Parthasarathy R, Cote G J, Gagel R F
Department of Internal Medicine Specialties, The University of Texas M.D. Anderson Cancer Center, Houston 77030, USA.
Cancer Res. 1999 Aug 15;59(16):3911-4.
Activating mutations of the RET proto-oncogene cause hereditary medullary thyroid carcinoma. To examine whether selective inactivation of mutant RET could prevent transformation, a hammerhead ribozyme was designed to cleave RET mRNA containing a transforming mutation of codon 634 TGC --> TAC (Cys634Tyr). In vitro RNA cleavage assay demonstrated that the ribozyme selectively cleaved RET RNA with a Cys634Tyr but not Cys634Arg or the normal sequence. Expression of ribozyme in NIH/3T3 cells prevented RET-mediated colony formation in soft agar. This inhibition required catalytically active ribozyme and was specific for the TAC mutation. Therefore, ribozymes designed to selectively target mutant RET RNA may provide an effective therapeutic in the treatment of this syndrome.
RET原癌基因的激活突变会导致遗传性甲状腺髓样癌。为了研究选择性失活突变型RET是否能阻止细胞转化，设计了一种锤头状核酶来切割含有密码子634由TGC突变为TAC（Cys634Tyr）的转化突变的RET mRNA。体外RNA切割试验表明，该核酶能选择性切割含有Cys634Tyr的RET RNA，但不能切割含有Cys634Arg或正常序列的RET RNA。核酶在NIH/3T3细胞中的表达可阻止RET介导的软琼脂集落形成。这种抑制作用需要具有催化活性的核酶，并且对TAC突变具有特异性。因此，设计用于选择性靶向突变型RET RNA的核酶可能为该综合征的治疗提供一种有效的治疗方法。
