Isocyanide Substitution in Acridine Orange Shifts DNA Damage-Mediated Phototoxicity to Permeabilization of the Lysosomal Membrane in Cancer Cells

Abstract

In cancer therapy, immunogenic cell death eliminates tumor cells more efficiently than conventional apoptosis. During photodynamic therapy (PDT), some photosensitizer (PS) targeting lysosomes divert apoptosis to the immunologically more relevant necrosis-like cell death. Acridine orange (AO) is a PS targeting lysosome. We synthesized a new compound, 3-N,N-dimethylamino-6-isocyanoacridine (DM), a modified AO, aiming to target lysosomes better. To compare DM and AO, we studied optical properties, toxicity, cell internalization, and phototoxicity. In addition, light-mediated effects were monitored by the recently developed QUINESIn method on nuclei, and membrane stability, morphology, and function of lysosomes utilizing fluorescent probes by imaging cytometry in single cells. DM proved to be a better lysosomal marker at 405 nm excitation and lysed lysosomes more efficiently. AO injured DNA and histones more extensively than DM. Remarkably, DM’s optical properties helped visualize shockwaves of nuclear DNA released from cells during the PDT. The asymmetric polar modification of the AO leads to a new compound, DM, which has increased efficacy in targeting and disrupting lysosomes. Suitable AO modification may boost adaptive immune response making PDT more efficient.

Excessive mechanical stress mediated Piezo1 activation regulates lysosomal membrane permeabilization-induced chondrocyte apoptosis in mouse osteoarthritis model

“…The distribution of AO dye was used to evaluate LMP, as previously reported 42 . Chondrocytes were incubated with 10 mg/ml AO dye (Yuanye Bio-Technology, Shanghai, China) at 37•C for 15 min.…”

Preparation and Optical Study of 1-Formamido-5-Isocyanonaphthalene, the Hydrolysis Product of the Potent Antifungal 1,5-Diisocyanonaphthalene

“…Utilizing the strong electron withdrawing (EW) nature of the isonitrile group, Nagy et al recently developed a novel class of push-pull fluorophores, where the isocyanide group is connected to an aromatic amine [11][12][13][14][15][16][17][18][19][20][21][22]. The resulting intramolecular charge transfer (ICT) gives rise to excellent solvatochromic properties, as we previously demonstrated through 1-amino-5-isocyanonaphthalene (ICAN) [11].…”

“…The resulting intramolecular charge transfer (ICT) gives rise to excellent solvatochromic properties, as we previously demonstrated through 1-amino-5-isocyanonaphthalene (ICAN) [11]. The spectrophysical properties are easily controlled by the relative positions of the -NH2 and -NC groups [12], as well as the substituents (reactive [14,16] or inert [13,18,22]) on the -NH2 group or by exchanging the aromatic core [19][20][21]. The synthesis of ICAN derivatives is cheap and straightforward since the respective aromatic diamine is reacted smoothly with in situgenerated dichlorocarbene (:CCl2) in basic solution [11].…”

Optical Study of Solvatochromic Isocyanoaminoanthracene Dyes and 1,5-Diaminoanthracene

“…ICANs can also be utilized in silver analytics as isocyanide ligands [26] and the simultaneous presence of the amino, isocyano and naphthalene groups yielded a most effective antifungal drug, the efficacy of which was demonstrated in vivo in mice against Candida strains [30]. Moreover, the small modification of acridine orange (the aromatic core is very similar to the anthracene in this study) resulted in a very efficient physiological pH-probe [31] and the new isocyano-aminoacridines opened up a new pathway in cancer treatment based on phototoxicity studies [32].…”