p53 makes a comeback

Cancer One reason that cancer cells are so difficult to kill is that they often lack p53, a key tumor suppressor that promotes apoptosis. To address this problem, Kong et al. devised a way to restore p53 gene expression in tumors by delivering p53 messenger RNA (mRNA) in nanoparticles. To minimize damage to healthy tissues, the authors used redox-responsive nanoparticles, taking advantage of the relative hypoxia of tumors. The use of mRNA rather than DNA provided an additional safeguard because mRNA acts directly in the cytoplasm, without integrating into host cell DNA and introducing mutations. The researchers tested their approach in multiple models in vitro and in vivo, with promising results. Sci. Transl. Med. 11 , eaaw1565 (2019).