University of Utah, 30 S 2000 E Room #301, Salt Lake City, UT, 84112, USA.
New York University, 31 Washington Pl, New York, NY, 10003, USA.
J Ovarian Res. 2019 Apr 30;12(1):38. doi: 10.1186/s13048-019-0514-4.
Despite years of research, the treatment options and mortality rate for ovarian cancer remain relatively stagnant. Resistance to chemotherapy and high heterogeneity in mutations contribute to ovarian cancer's lethality, including many mutations in tumor suppressor p53. Though wild type p53 gene therapy clinical trials failed in ovarian cancer, mitochondrially-targeted p53 fusion constructs, including a fusion with pro-apoptotic protein Bad, have shown much higher apoptotic potential than wild type p53 in vitro. Due to the inherent toxicities of mitochondrial apoptosis, cancer-specificity for the p53 fusion constructs must be developed. Cancer-specific promoters such as hTERT, hTC, Brms1, and Ran have shown promise in ovarian cancer.
Of five different lengths of hTERT promoter, the - 279/+ 5 length relative to the transcription start site showed the highest activity across a panel of ovarian cancer cells. In addition to - 279/+ 5, promoters hTC (an hTERT/CMV promoter hybrid), Brms1, and Ran were tested as drivers of mitochondrially-targeted p53-Bad and p53-Bad* fusion gene therapy constructs. p53-Bad* displayed cancer-specific killing in all ovarian cancer cell lines when driven by hTC, - 279/+ 5, or Brms1.
Cancer-specific promoters hTC, - 279/+ 5, and Brms1 all display promise in driving p53-Bad* gene therapy for treatment of ovarian cancer and should be moved forward into in vivo studies. -279/+ 5 displays lower expression levels in fewer cells, but greater cancer specificity, rendering it most useful for gene therapeutics with high toxicity to normal cells. hTC and Brms1 show higher transfection and expression levels with some cancer specificity, making them ideal for lowering toxicity in order to increase dose without as much of a reduction in the number of cancer cells expressing the gene construct. Having a variety of promoters available means that patient genetic testing can aid in choosing a promoter, thereby increasing cancer-specificity and giving patients with ovarian cancer a greater chance at survival.
尽管经过多年的研究，卵巢癌的治疗选择和死亡率仍然相对停滞不前。化疗耐药性和突变的高度异质性导致了卵巢癌的致命性，其中包括肿瘤抑制因子 p53 的许多突变。尽管野生型 p53 基因治疗临床试验在卵巢癌中失败，但靶向线粒体的 p53 融合构建物，包括与促凋亡蛋白 Bad 的融合，在体外显示出比野生型 p53 更高的凋亡潜力。由于线粒体凋亡的固有毒性，必须开发针对 p53 融合构建物的癌症特异性。hTERT、hTC、Brms1 和 Ran 等癌症特异性启动子在卵巢癌中显示出了希望。
在卵巢癌细胞系中，相对于转录起始位点的 -279/+5 长度的 hTERT 启动子的五种不同长度中显示出最高的活性。除了 -279/+5 之外，还测试了 hTC（hTERT/CMV 启动子杂交物）、Brms1 和 Ran 作为靶向线粒体的 p53-Bad 和 p53-Bad融合基因治疗构建物的驱动子。当由 hTC、-279/+5 或 Brms1 驱动时，p53-Bad在所有卵巢癌细胞系中均显示出癌症特异性杀伤。
癌症特异性启动子 hTC、-279/+5 和 Brms1 都显示出在驱动 p53-Bad*基因治疗治疗卵巢癌方面的潜力，应该推进到体内研究中。-279/+5 在更少的细胞中表达水平更低，但具有更高的癌症特异性，使其最适合用于对正常细胞具有高毒性的基因治疗。hTC 和 Brms1 显示出更高的转染和表达水平，具有一定的癌症特异性，使其成为降低毒性的理想选择，从而增加剂量而不会减少表达基因构建物的癌细胞数量。有多种启动子可供选择意味着患者的基因检测可以帮助选择启动子，从而提高癌症特异性，并为卵巢癌患者提供更高的生存机会。
