mRNA cancer vaccines demonstrate potential in clinical trials, but existing platforms struggle to boost antitumor efficacy without added cost or complexity. Here, we present a streamlined linear cap-independent mRNA (LciRNA) cancer vaccine platform, achieved by fusing a UPA protective sequence, composed of a viral exoribonuclease-resistant RNA (xrRNA) and a poly(A) binding protein (PABP) motif, to an optimized Enterovirus A internal ribosome entry site. UPA impedes exonuclease-mediated decay and recruits RNA-binding proteins to stabilize LciRNA, enabling stable in vivo expression without 5’ capping or modifications. Moreover, LciRNA innately stimulates immune responses by engaging pattern-recognition receptors, promoting dendritic cell maturation, and upregulating proinflammatory signals. In murine melanoma and HPV-associated tumor models, this vaccine platform elicits strong systemic and intra-tumoral T cell responses, achieving superior tumor control, demonstrating how immune stimulation-translation synergy underpins its efficacy. Thus, we present a cost-effective platform with enhanced efficacy, and highlight coupled immune stimulation and translation as a paradigm for future mRNA cancer vaccines. mRNA vaccines hold promise as cancer therapeutics. However, production complexity and prohibitive manufacturing costs limit the applicability of these vaccine platforms. Here, the authors present an engineered linear Cap-independent mRNA vaccine design that achieves stable in vivo expression and elicits robust anti-tumor immune responses in preclinical mouse models.
Yu et al. (2026) studied this question.