Novel In Vitro Selection of -Acting mRNA-Cleaving Deoxyribozymes for Cancer Therapy.

The B Cell Lymphoma-2 () family proteins are central regulators of apoptosis, and their dysregulation is frequently associated with cancer progression and resistance to therapy. While small molecules like venetoclax have shown promise, nucleic acid-based therapeutics targeting remain underexplored. Here, we report a novel in vitro evolution strategy to generate trans-acting RNA-cleaving DNAzymes targeting natural mRNA without requiring covalent substrate-linking. Using a 50-base region of mRNA as a selection target, we evolved several DNAzymes that demonstrate significant RNA cleavage activity. These DNAzymes downregulated expression, induced apoptosis, and reduced cell viability in HepG2 and MCF-7 cancer cells. In vivo, our novel DNAzymes significantly suppressed tumor growth in a syngeneic mouse breast cancer model, with efficacy comparable to 5-Fluorouracil. This study presents a proof of concept for a novel strategy to evolve functional DNAzymes against native mRNA sequences and highlights their potential as gene-silencing tools in cancer therapy. Future studies will explore the therapeutic potential of these findings in cancer patients. Additionally, investigating the underlying molecular mechanisms in more complex cancer models will further validate the observed effects.