Bravo-Estupiñan Diana M, Geiß Carsten, Arias-Arias Jorge L, Montaño-Samaniego Mariela, Chinchilla-Monge Ricardo, Marín-Müller Christian, Quirós-Barrantes Steve, Régnier-Vigouroux Anne, Ibáñez-Hernández Miguel, Mora-Rodríguez Rodrigo A
Programa de Doctorado en Ciencias, Sistema de Estudios de Posgrado (SEP), Universidad de Costa Rica, San José 20601, Costa Rica.
Laboratorio de Quimiosensibilidad Tumoral (LQT), Centro de Investigación en Enfermedades Tropicales (CIET), Facultad de Microbiología, Universidad de Costa Rica, San José 20601, Costa Rica.
Cells. 2025 Sep 4;14(17):1384. doi: 10.3390/cells14171384.
Genomic instability, a hallmark of cancer, leads to copy number variations disrupting gene dosage balance and contributing to tumor progression. One of the most affected oncogenes is MYC, whose overexpression is tightly regulated to avoid cytotoxicity. In aneuploid cancer cells, gene dosage compensation mechanisms involving microRNAs (miRNAs) from the miR-17/92 cluster contribute in regulating MYC expression. Targeting this miRNA-mediated compensation system represents a promising therapeutic strategy leading to an uncontrolled and lethal MYC overexpression.
Synthetic miRNA sponges targeting miR-17, miR-19a, and miR-20a, key regulators of MYC dosage compensation, were designed and validated. Breast cancer cells (MCF7) with stable exogenous MYC overexpression were used to assess the impact of sponge constructs on MYC regulation. Quantitative RT-PCR revealed a significant reduction in miRNA expression and a corresponding increase in endogenous MYC levels upon sponge treatment. Functional assays in multiple colorectal cancer cell lines with varying MYC copy numbers demonstrated a time-dependent increase in cell death following sponge transfection. Cytotoxic effects increased with MYC copy number, confirming a correlation between gene dosage sensitivity and therapeutic response.
Our findings demonstrate that miRNA sponges targeting the miR-17/92 cluster can effectively disrupt MYC dosage compensation, leading to selective cytotoxicity in MYC-amplified cancer cells.
基因组不稳定是癌症的一个标志，会导致拷贝数变异，破坏基因剂量平衡并促进肿瘤进展。受影响最严重的癌基因之一是MYC，其过表达受到严格调控以避免细胞毒性。在非整倍体癌细胞中，涉及miR-17/92簇微小RNA（miRNA）的基因剂量补偿机制有助于调节MYC表达。靶向这种miRNA介导的补偿系统代表了一种有前景的治疗策略，可导致失控且致命的MYC过表达。
设计并验证了靶向MYC剂量补偿关键调节因子miR-17、miR-19a和miR-20a的合成miRNA海绵。使用稳定外源性过表达MYC的乳腺癌细胞（MCF7）来评估海绵构建体对MYC调节的影响。定量RT-PCR显示，海绵处理后miRNA表达显著降低，内源性MYC水平相应升高。在多种具有不同MYC拷贝数的结肠癌细胞系中进行的功能测定表明，海绵转染后细胞死亡呈时间依赖性增加。细胞毒性作用随MYC拷贝数增加而增强，证实了基因剂量敏感性与治疗反应之间的相关性。
我们的研究结果表明，靶向miR-17/92簇的miRNA海绵可有效破坏MYC剂量补偿，导致MYC扩增的癌细胞产生选择性细胞毒性。
