Research advances in the biosynthetic pathway and high-yield strains of ansamitocins

Ansamitocin P-3 (AP-3), a potent cytotoxic payload for antibody-drug conjugates (ADCs), holds significant clinical value in targeted tumor therapy. However, its industrialization is hindered by low fermentation titers and high production costs, underscoring the critical need for research into its high-yield mechanisms and technologies. This review systematically summarizes recent advances in strategies to enhance AP-3 <?A3B2 pi129?>production, focusing on its biosynthetic pathway and the engineering of high-yield strains of Actinosynnema pretiosum. Elucidation of the AP-3 <?A3B2 pi129?>biosynthetic mechanism has clarified the modular organization of the polyketide synthase (PKS) gene cluster and the nonlinear post-modification enzymatic network. Furthermore, it has revealed the multi-target self-cytotoxicity of AP-3 <?A3B2 pi129?>against the producing strain and identified the regulatory roles of key factors, such as Asm8 <?A3B2 pi129?>and AdpA_1075. In strain development, the integration of traditional mutagenesis (e.g., UV, MNNG) and atmospheric and room temperature plasma (ARTP) with modern molecular tools like CRISPR-Cas9 <?A3B2 pi129?>has yielded remarkable results. Success has been achieved through targeted attenuation of competitive pathways, reinforcement of rate-limiting steps (e.g., supply of AHBA and methylmalonyl-CoA), engineering of regulatory factors, and alleviation of product feedback inhibition. Innovations in metabolic regulation have enabled precise optimization of precursor supply and the dynamic balancing of cofactors such as SAM and NADPH. In addition, breakthroughs in fermentation technology, including time-dependent carbon source control, enhanced oxygen transfer, and pulse-feeding strategies, have been validated for industrial feasibility in scaled-up bioreactors. The highest reported AP-3 <?A3B2 pi129?>titer of 757.7 mg/L stands as a key milestone. Finally, we summarize the primary bottlenecks hindering the industrialization of AP-3 <?A3B2 pi129?>production and propose future research directions. These focus on integrating dynamic metabolic regulation with intelligent fermentation technologies to further improve efficiency and reduce costs. This integrated approach is expected to accelerate the industrial translation of AP-3 <?A3B2 pi129?>and ensure a stable supply of this high-value cytotoxic payload for the development and clinical application of ADC drugs. <alternatives id="alt1"> </alternatives>