image: Schematic illustration of the construction of conjugates I and II. Schematic illustration of the combinational effects on tumours of the PtIV-MSA-2 conjugates. The PtIV-MSA-2 conjugates are reduced to PtII species and MSA-2 in tumour tissues. The PtII species kill tumour cells, causing the release of DNA fragments to activate STING in DCs, which is also amplified by free MSA-2. STING activation in DCs promotes IFN-β secretion to activate CD8+ T and NK cells, which release IFN-γ and GzmB for tumour killing. All these factors eventually amplify the antitumour therapeutic effects.
Credit: ©Science China Press
Traditionally, therapies combining DNA-damaging agents and STING agonists have shown potential in treating cancer by enhancing immune response and reshaping the tumor microenvironment. However, until now, creating a single molecular entity housing both agents remained elusive.
Enter the game-changer—two Pt-MSA-2 conjugates (I and II). These ingenious compounds bring together the DNA-damaging power of cisplatin and the immune-activating strength of STING agonist MSA-2. Excitingly, these conjugates exhibit remarkable potential as versatile small-molecule drugs specifically targeting pancreatic cancer.
Detailed studies uncovered that conjugate I not only elevated the expression of innate immunity and metabolism-related transcripts in cancer cells but also demonstrated a distinct profile compared to cisplatin and MSA-2. Exploring the tumor microenvironment revealed that conjugate I could boost the infiltration of natural killer (NK) cells into tumors and trigger the activation of T cells, NK cells, and dendritic cells (DCs) within tumor tissues.
This groundbreaking finding suggests that conjugate I, born from the fusion of a Pt chemotherapeutic drug and a STING agonist, stands as a promising and potent candidate for anticancer drug development. This opens up exciting new avenues for metalloimmunotherapy, marking a significant stride in the ongoing battle against cancers.
See the article:
Combining cisplatin and a STING agonist into one molecule for metalloimmunotherapy of cancer
https://doi.org/10.1093/nsr/nwae020
Journal
National Science Review