Synthesis and Human Telomerase Inhibition of a Series of Regioisomeric Disubstituted Amidoanthraquinones
作者:Hsu-Shan Huang、In-Been Chen、Kuo-Feng Huang、Wei-Chih Lu、Fu-Ying Shieh、Yi-Yuan Huang、Fong-Chun Huang、Jing-Jer Lin
DOI:10.1248/cpb.55.284
日期:——
Telomerase is the enzymatic activity that maintains the ends of eukaryotic chromosomes. Telomerase activity is detected in most tumor cells whereas it is low or undetectable in most normal somatic cells. Expression of the telomerase catalytic component, the human telomerase reverse transcriptase (hTERT), is believed to be controlled primarily at the level of transcription. Because of this selective expression property of telomerase, it has been touted as a specific target for antitumor chemotherapeutics. However, a concern for the applicability of telomerase inhibitors is that they require a long lag time for telomeres to be shortened to critical length before cancer cells stop proliferating. Here we investigate telomerase inhibitory, cytotoxicity and the hTERT repressing effects on a number of synthesized 2,6-diamidoanthraquinones and 1,5-diamidoanthraquinones as compared to their disubstituted homologues. We found that several of the 1,5-diamidoanthraquinones and 2,6-diamidoanthraquinones inhibited telomerase activity effectively with IC50 at the sub-micro to micro molar range and caused acute cytotoxicity to cancer cells with EC50 similar or better than that of mitoxantrone. Particularly, 2,6-diamidoanthraquinone with 2-ethylaminoacetamido side chains 33, even though not affecting cell proliferation, showed to be endowed with a strong telomerase effect, probably related to a marked stabilization of the G-quadruplex-binding structure. The results suggested that these compounds caused multiple effects to cancer cells. More significantly, they overcome the long lag period problem of classical telomerase inhibitors that they are also potent cytotoxic agents. These results greatly expand the potential of tricyclic anthraquinone pharmacophore in preventive and/or curative therapy.
端粒酶是维持真核染色体末端的酶活性。在大多数肿瘤细胞中都能检测到端粒酶活性,而在大多数正常体细胞中,端粒酶活性很低或检测不到。端粒酶催化成分人类端粒酶逆转录酶(hTERT)的表达被认为主要受转录水平的控制。由于端粒酶的这种选择性表达特性,它被誉为抗肿瘤化疗药物的特异性靶点。然而,端粒酶抑制剂的适用性令人担忧,因为在癌细胞停止增殖之前,端粒需要较长的滞后时间才能缩短到临界长度。在这里,我们研究了一些合成的 2,6-二氨基蒽醌和 1,5-二氨基蒽醌与它们的二取代同系物相比所具有的端粒酶抑制作用、细胞毒性和 hTERT 抑制作用。我们发现,其中几种 1,5-二氨基蒽醌和 2,6-二氨基蒽醌能有效抑制端粒酶活性,其 IC50 在亚微量至微量摩尔范围内,对癌细胞的急性细胞毒性 EC50 与米托蒽醌相似或更高。特别是带有 2- 乙氨基乙酰氨基侧链 33 的 2,6-二氨基蒽醌,虽然不影响细胞增殖,但却具有很强的端粒酶作用,这可能与 G-四联体结合结构的明显稳定有关。研究结果表明,这些化合物对癌细胞具有多重作用。更重要的是,这些化合物克服了传统端粒酶抑制剂滞后期长的问题,它们同时也是强效的细胞毒剂。这些结果大大拓展了三环蒽醌类药物在预防和/或治疗方面的潜力。