NIR-Responsive Silicon-Rhodamine Based Photosensitizer: A Promising Approach For Glioblastoma Treatment

Date

2025-4

Author

Özoğul, Naz

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Glioblastoma multiforme (GBM) is a highly lethal brain cancer with poor prognosis due to its aggressive and heterogeneous nature. Photodynamic therapy (PDT) has emerged as a promising alternative for GBM treatment. In this study, we present SiCNBr, a novel silicon-rhodamine-based photosensitizer synthesized and characterized for the first time and evaluate its anticancer potential under near-infrared (NIR) light activation. Cytotoxicity assays were performed on genetically distinct glioblastoma cell lines (U-87 MG, T98 G, U-118 MG) and a healthy fibroblast line (L929). While SiCNBr showed no dark toxicity, it induced significant phototoxicity in U-87 MG cells, with the lowest IC₅₀ value determined as 3.04 µM. No significant effect was observed in T98 G and U-118 MG cells. The compound also exhibited phototoxicity in the healthy L929 line, guiding subsequent experiments to focus on U-87 MG cells. To elucidate the mechanism of action, ROS scavenger assays were conducted, revealing a predominant increase in general ROS levels and a partial contribution from singlet oxygen. These findings were further supported by confocal fluorescence imaging, which confirmed intracellular ROS accumulation. Subcellular localization studies showed that SiCNBr accumulates primarily in mitochondria, with partial lysosomal presence. Importantly, due to its fluorescent properties and compatibility with confocal imaging, SiCNBr also functions as a theranostic agent—offering both therapeutic efficacy and diagnostic traceability. These results collectively demonstrate that SiCNBr is a potent and selectively phototoxic agent in GBM and holds promise for further development as a dual-purpose therapeutic and diagnostic candidate.

Subject Keywords

Cancer, Glioblastoma Multiforme, Photodynamic Therapy, Photosensitizer, Near-IR activatable

URI

https://hdl.handle.net/11511/114933

Collections

Graduate School of Natural and Applied Sciences, Thesis