Holden Lorcan, Curley Rhianne C, Avella Giuseppe, Long Conor, Keyes Tia E
School of Chemical Sciences National Center for Sensor Research, Dublin City University, Dublin, 9, Ireland.
Angew Chem Int Ed Engl. 2024 Oct 7;63(41):e202408581. doi: 10.1002/anie.202408581. Epub 2024 Sep 5.
A first example of a mitochondrial G-quadruplex (mitoG4s) targeted Ru(II) photooxidant complex is reported. The complex, Ru-TAP-PDC3 induces photodamage toward guanine quadruplexes (G4s) located in the mitochondrial genome under hypoxic and normoxic conditions. Ru-TAP-PDC3 shows high affinity for mitoG4s and localises within mitochondria of live HeLa cells. Immunolabelling with anti-G4 antibody, BG4, confirms Ru-TAP-PDC3 associates with G4s within the mitochondria of fixed cells. The complex induces depletion of mtDNA in live cells under irradiation at 405 nm, confirmed by loss of PicoGreen signal from mitochondria. Biochemical studies confirm this process induces apoptosis. The complex shows low dark toxicity and an impressive phototoxicity index (PI) of >89 was determined in Hela under very low intensity irradiation, 5 J/cm. The phototoxicity is thought to operate through both Type II singlet oxygen and Type III pathways depending on normoxic or hypoxic conditions, from live cell assays and plasmid DNA cleavage. Overall, we demonstrate targeting mitoG4s and mtDNA with a photooxidant is a potent route to achieving apoptosis under hypoxic conditions that can be extended to phototherapy.
报道了一种靶向线粒体G-四链体（mitoG4s）的钌（II）光氧化剂复合物的首个实例。该复合物Ru-TAP-PDC3在缺氧和常氧条件下对位于线粒体基因组中的鸟嘌呤四链体（G4s）诱导光损伤。Ru-TAP-PDC3对mitoG4s表现出高亲和力，并定位于活HeLa细胞的线粒体内。用抗G4抗体BG4进行免疫标记，证实Ru-TAP-PDC3与固定细胞线粒体内的G4s相关联。该复合物在405 nm照射下诱导活细胞中线粒体DNA（mtDNA）的消耗，线粒体中PicoGreen信号的丧失证实了这一点。生化研究证实该过程诱导细胞凋亡。该复合物显示出低暗毒性，并且在极低强度照射（5 J/cm）下，在Hela细胞中测定的光毒性指数（PI）>89，令人印象深刻。根据活细胞分析和质粒DNA切割，认为光毒性通过II型单线态氧和III型途径起作用，这取决于常氧或缺氧条件。总体而言，我们证明用光氧化剂靶向mitoG4s和mtDNA是在缺氧条件下实现细胞凋亡的有效途径，这可以扩展到光疗。
