BODIPY-dipicolylamine complexes of platinum(ii): X-ray structure, cellular imaging and organelle-specific near-IR light type-II PDT

Bera, A and Gautam, S and Raza, MK and Pal, AK and Kondaiah, P and Chakravarty, AR (2022) BODIPY-dipicolylamine complexes of platinum(ii): X-ray structure, cellular imaging and organelle-specific near-IR light type-II PDT. In: Dalton Transactions, 51 (10). pp. 3925-3936.

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Abstract

Dipicolylamine (dpa) based platinum(ii) complexes [Pt(L1-3)Cl]Cl (1-3), where L2 and L3 are green and red light BODIPY-tagged dpa ligands and L1 is a benzyl derivative of dpa, were synthesized and characterized and their in vitro cytotoxicity was studied. The perchlorate salt of complex 2 was structurally characterized. It showed a PtN3Cl core with a deformed square-planar geometry. At pH 7.2, complexes 2 and 3 showed strong absorption bands at 500 nm (ϵ ∼6.8 × 104 dm3 mol−1 cm−1) and 653 nm (ϵ ∼1.0 × 105 dm3 mol−1 cm−1) in a 1 : 1 (v/v) mixture of dimethyl sulfoxide and Dulbecco's phosphate-buffered saline (DMSO/DPBS), respectively. They displayed respective emission bands at 515 and 677 nm having fluorescence quantum yield values of 0.36 and 0.25. Complex 3 generated singlet oxygen, as evidenced from the 1,3-diphenylisobenzofuran titration experiments and mechanistic DNA photocleavage study. It showed high photocytotoxicity in red light (600-720 nm) with half-maximal inhibitory concentration (IC50) values of 1.73 and 2.67 μM in HeLa and A549 cells. The complexes showed significantly reduced chemo-PDT activity in a non-cancerous HPL1D cell line and in the dark. The 2′,7′-dichlorofluorescein diacetate assay revealed reactive oxygen species-mediated type-II photodynamic therapy (PDT) activity. Cellular imaging of A549 cancer cells using complexes 2 and 3 revealed their preferential localization in mitochondria and endoplasmic reticulum. The annexin V-FITC/PI assay confirmed apoptotic cell damage. Cell cycle analysis indicated arrest in the G1 phase upon red light irradiation. Pt-DNA adduct formation was proposed from a DNA binding experiment with green light active complex 2 and 9-ethylguanine as a nucleobase from the mass spectral study.

Item Type:	Journal Article
Publication:	Dalton Transactions
Publisher:	Royal Society of Chemistry
Additional Information:	The copyright for this article belongs to the Royal Society of Chemistry.
Keywords:	Cell culture; Cell proliferation; Chlorine compounds; Dimethyl sulfoxide; DNA; Geometry; Inorganic compounds; Lanthanum compounds; Organic solvents; Oxygen; Platinum compounds; Spectroscopic analysis; Synthesis (chemical); Titration, Benzyl derivatives; Cellular imaging; Cellular organelles; Green light; Near-IR light; Platinum complexes; Red light; Synthesised; Type II; X-ray structure, Photodynamic therapy, 2,2'-dipicolylamine; 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene; amine; boron derivative; coordination compound; photosensitizing agent; picolinic acid derivative; platinum, apoptosis; cell cycle; cell organelle; chemical structure; chemistry; drug effect; human; infrared radiation; molecular model; photochemotherapy; single cell analysis; tumor cell line; X ray crystallography, Amines; Apoptosis; Boron Compounds; Cell Cycle; Cell Line, Tumor; Coordination Complexes; Crystallography, X-Ray; Humans; Infrared Rays; Models, Molecular; Molecular Structure; Organelles; Photochemotherapy; Photosensitizing Agents; Picolinic Acids; Platinum; Single-Cell Analysis
Department/Centre:	Division of Biological Sciences > Molecular Reproduction, Development & Genetics Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	27 Jun 2022 05:40
Last Modified:	27 Jun 2022 05:40
URI:	https://eprints.iisc.ac.in/id/eprint/73884

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