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Bassler MC, Rammler T, Wackenhut F, Zur Oven-Krockhaus S, Secic I, Ritz R, Meixner AJ, Brecht M. Accumulation and penetration behavior of hypericin in glioma tumor spheroids studied by fluorescence microscopy and confocal fluorescence lifetime imaging microscopy. Anal Bioanal Chem 2022; 414:4849-4860. [PMID: 35538227 PMCID: PMC9234035 DOI: 10.1007/s00216-022-04107-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 04/14/2022] [Accepted: 04/28/2022] [Indexed: 12/17/2022]
Abstract
Glioblastoma WHO IV belongs to a group of brain tumors that are still incurable. A promising treatment approach applies photodynamic therapy (PDT) with hypericin as a photosensitizer. To generate a comprehensive understanding of the photosensitizer-tumor interactions, the first part of our study is focused on investigating the distribution and penetration behavior of hypericin in glioma cell spheroids by fluorescence microscopy. In the second part, fluorescence lifetime imaging microscopy (FLIM) was used to correlate fluorescence lifetime (FLT) changes of hypericin to environmental effects inside the spheroids. In this context, 3D tumor spheroids are an excellent model system since they consider 3D cell-cell interactions and the extracellular matrix is similar to tumors in vivo. Our analytical approach considers hypericin as probe molecule for FLIM and as photosensitizer for PDT at the same time, making it possible to directly draw conclusions of the state and location of the drug in a biological system. The knowledge of both state and location of hypericin makes a fundamental understanding of the impact of hypericin PDT in brain tumors possible. Following different incubation conditions, the hypericin distribution in peripheral and central cryosections of the spheroids were analyzed. Both fluorescence microscopy and FLIM revealed a hypericin gradient towards the spheroid core for short incubation periods or small concentrations. On the other hand, a homogeneous hypericin distribution is observed for long incubation times and high concentrations. Especially, the observed FLT change is crucial for the PDT efficiency, since the triplet yield, and hence the O2 activation, is directly proportional to the FLT. Based on the FLT increase inside spheroids, an incubation time > 30 min is required to achieve most suitable conditions for an effective PDT.
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Affiliation(s)
- Miriam C Bassler
- Process Analysis and Technology (PA&T), Reutlingen University, Alteburgstr. 150, 72762, Reutlingen, Germany.,Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany
| | - Tim Rammler
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany
| | - Frank Wackenhut
- Process Analysis and Technology (PA&T), Reutlingen University, Alteburgstr. 150, 72762, Reutlingen, Germany.
| | - Sven Zur Oven-Krockhaus
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany
| | - Ivona Secic
- Process Analysis and Technology (PA&T), Reutlingen University, Alteburgstr. 150, 72762, Reutlingen, Germany
| | - Rainer Ritz
- Department of Neurosurgery, Schwarzwald-Baar Clinic, Klinikstr. 11, 78052, Villingen-Schwenningen, Germany
| | - Alfred J Meixner
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany
| | - Marc Brecht
- Process Analysis and Technology (PA&T), Reutlingen University, Alteburgstr. 150, 72762, Reutlingen, Germany. .,Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany.
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Chatkon A, Chatterjee PB, Sedgwick MA, Haller KJ, Crans DC. Counterion Affects Interaction with Interfaces: The Antidiabetic Drugs Metformin and Decavanadate. Eur J Inorg Chem 2013. [DOI: 10.1002/ejic.201201345] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Mukherjee P, Adhikary R, Halder M, Petrich JW, Miskovsky P. Accumulation and interaction of hypericin in low-density lipoprotein--a photophysical study. Photochem Photobiol 2008; 84:706-12. [PMID: 18435618 DOI: 10.1111/j.1751-1097.2007.00234.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The accumulation and interaction of hypericin with the biologically important macromolecule, low-density lipoprotein (LDL), is investigated using various steady-state and time-resolved fluorescence measurements. It is concluded that multiple hypericins can penetrate considerably deeply into the LDL molecule. Up to approximately 20 nonaggregated hypericin molecules can enter LDL; but upon increasing the hypericin concentration, the fluorescence lifetime of hypericin decreases drastically, suggesting most likely the self-quenching of aggregated hypericin. There is also evidence of energy transfer from tryptophans of the constituent protein, apoB-100, to hypericin in LDL. The results demonstrate the ability of LDL to solubilize hypericin (a known photosensitizer) in nonaggregated form, which has implications for the construction of drug delivery systems.
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