ALKYLATING & CLEAVING ANTIC-MYC DNAS FOR BREAST CANCER

每九个妇女中就有一个患乳腺癌。在乳腺癌的众多指标和预后因素中，c- MYC原癌基因在许多早期和晚期乳腺肿瘤中扩增和过表达。在针对病毒和致癌基因的人体临床试验中，反义DNA疗法被证明是有效的。核酸酶抗性反应性寡核苷酸为干预具有活化癌基因的恶性细胞提供了强有力的工具。该建议的假设是，寡核苷酸疗法将通过在亚毒性剂量下特异性地消融乳腺癌细胞中的c-MYC过表达来实现抗增殖效力。为此，新西伯利亚实验室将合成烷基化[4-（n -2-氯乙基，n -甲氨基）苯基甲氨基]和切割（博来霉素A5）核酸酶抗性磷硫酸dna衍生物，2'- o -甲基rna及其嵌合体，用吩嗪和/或类固醇修饰增强，靶向c-MYC mRNA靶标。独特的杂双功能寡核苷酸衍生物具有3'-胆固醇和5'-反应基团，有效地渗透到细胞内，抵抗细胞内核酸酶，并特异性修饰核酸位点。新西伯利亚实验室还将合成耐核酸酶的三聚体形成DNA的博来霉素A5衍生物，用非那嗪和/或类固醇修饰增强，针对c-myc DNA寡嘌呤启动子序列。费城实验室将在致瘤性人乳腺癌细胞系BT474中测试反应性寡核苷酸的抗原减少和抗增殖效果，BT474过度表达c-MYC，而MCF7细胞在没有雌激素刺激的情况下不过度表达c-MYC。这项新的联合努力是由史密斯博士访问新西伯利亚实验室开始的，目的是测量抗c-MYC博来霉素A5低聚物与c-MYC RNA的反应性。在未来的几年里，在细胞培养中确定的最有效的抗核酸酶活性寡核苷酸将通过测量皮下植入BT474和MCF7细胞系对裸鼠肿瘤生长的抑制来测试临床前效力。

Breast cancer attacks one out of every nine women. Among the many indicators and prognostic factors in breast cancer, the c- MYC proto-oncogene is amplified and overexpressed in many early and advanced stage mammary tumors. Antisense DNA therapy is proving effective in human clinical trials against viruses and oncogenes. Nuclease resistant reactive oligonucleotides offer powerful tools for intervention against malignant cells with activated oncogenes. The hypothesis of this proposal is that oligonucleotide therapy will achieve antiproliferative potency by specifically ablating c-MYC overexpression in breast cancer cells at subtoxic doses. For this purpose, the Novosibirsk laboratory will synthesize alkylating [4-(N-2-chloroethyl, N-methylamino) benyzylmethylamino] and cleaving (bleomycin A5) derivatives of nuclease resistant phosphorothioate DNAs, 2'-O-methyl RNAs, and their chimeras, potentiated with phenazinium and/or steroid modifications, targeted against c-MYC mRNA targets. The unique heterobifunctional oligonucleotide derivatives with 3'- cholesterol and 5'-reactive groups efficiently penetrate into cells, resist intracellular nucleases, and modify nucleic acids site-specifically. The Novosibirsk laboratory will also synthesize bleomycin A5 derivatives of nuclease resistant triplex-forming DNAs, potentiated with phenazinium and/or steroid modifications, targeted against c-myc DNA oligopurine promoter sequences. The Philadelphia laboratory will test the antigen reduction and antiproliferative efficacy of the reactive oligonucleotides in a tumorigenic human breast cancer cell line, BT474, which overexpresses c-MYC, compared with MCF7 cells, which do not overexpress c-MYC without estrogen stimulation. This new joint effort has been initiated by the visit of Dr. Smith to the Novosibirsk laboratory to measure anti-c-MYC bleomycin A5 oligomer reactivity with c-MYC RNA. In future years, the most potent nuclease resistant reactive oligonucleotides determined in cell culture will then be tested for preclinical potency by measuring inhibition of tumor growth in nude mice due to subcutaneous implantation of the BT474 and MCF7 cell lines.