Identification of Highly Cytotoxic Antisense Oligonucleotides Targeting Essential Genes in Human Ovarian and Lung Cancer Cells.

Therapeutic nucleic acid (TNA)-based gene silencing strategies, such as antisense oligonucleotides (ASOs), have been explored for cancer treatment. However, no ASO-based anticancer drugs are currently available, largely because of limited therapeutic efficacy. Conventional ASO-based cancer therapies typically target oncogenes or cancer-associated genes because constitutively active ASOs may also damage normal tissues. We hypothesized that this limitation can be overcome by conditionally activating ASOs only in response to cancer-specific biomarkers. In this paradigm, therapeutic efficacy is determined by the potential of the released ASO rather than by the cancer specificity of its target, allowing any gene essential for cell survival to serve as a target. Our aim was to identify the most cytotoxic ASO sequences for cancer cells. We designed 37 ASOs targeting 13 candidate genes and evaluated them in human ovarian adenocarcinoma (SKOV3) and lung adenocarcinoma (A549) cell lines. An ASO targeting DARS1 exhibited the strongest activity, inducing apoptotic cell death in both cell types. Additional ASOs targeting DYNC1I2 and EIF2S3 were identified as effective candidates in SKOV3 and A549 cells, respectively. Importantly, the selected ASOs exhibited low toxicity toward the tested noncancerous cell line. These findings identify DARS1, DYNC1I2, and EIF2S3 as promising targets for marker-dependent ASO-based cancer therapy.