The co-silencing of multiple tumor suppressor genes can lead to escalated malignancy in cancer cells. Given the limited efficacy of anticancer therapies targeting single tumor suppressor genes, we developed small circular single-stranded DNA (CSSD) that can up-regulate the expression of co-silenced tumor suppressor genes by sequestering microRNAs (miRNAs) that negatively regulate these genes. We found that cancer patients with low tumor expression of the tumor suppressor genes KLF17, CDH1, and LASS2 had shortened survival times. The up-regulation of these genes upon transfection of artificial CSSD-9 inhibited tumor proliferation and metastasis and promoted apoptosis in vitro as well as in ex vivo and patient-derived xenograft models. In addition, CSSD is more stable and effective than current miRNA inhibitors, and transfecting CSSDs via nanoparticles substantially improved delivery efficiency. The use of a single CSSD can promote the inhibition of multiple tumor suppressor genes. This study provides evidence for the possibility of using CSSDs as therapeutic miRNA inhibitors to target the co-silencing of multiple tumor suppressor genes.

多种肿瘤抑制基因的共同沉默可导致癌细胞中恶性肿瘤的升级。鉴于针对单一肿瘤抑制基因的抗癌疗法疗效有限，我们开发了小的环状单链DNA（CSSD），可以通过隔离负调控这些基因的microRNA（miRNA）来上调共同沉默的肿瘤抑制基因的表达。我们发现肿瘤抑制基因KLF17，CDH1和LASS2的低肿瘤表达的癌症患者缩短了生存时间。人工CSSD-9转染后，这些基因的上调抑制了肿瘤的增殖和转移，并在体外以及离体和患者来源的异种移植模型中促进了细胞凋亡。另外，CSSD比目前的miRNA抑制剂更稳定和有效，并且通过纳米粒子转染CSSD大大提高了递送效率。单个CSSD的使用可以促进多种肿瘤抑制基因的抑制。这项研究提供了使用CSSD作为治疗性miRNA抑制剂靶向多种肿瘤抑制基因共同沉默的可能性的证据。