Related Experiment Video
Updated: Jan 3, 2026
Fluorescence Molecular Tomography for In Vivo Imaging of Glioblastoma Xenografts
Published on: April 26, 2018
Protoporphyrin IX tracer fluorescence modulation for improved brain tumor cell lines visualization.
Deborah Piffaretti1, Floriana Burgio2, Marcus Thelen3
1Laboratory for Biomedical Neurosciences, Neurocenter of Southern Switzerland, Ente Cantonale Ospedaliero, Torricella-Taverne, Switzerland; Faculty of Medicine, Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland.
Improving fluorescence-guided surgery for high-grade gliomas (HGGs) requires boosting protoporphyrin IX (PpIX) signal. This study identified factors reducing PpIX accumulation and tested drugs to enhance fluorescence, potentially improving tumor detection during surgery.
Area of Science:
- Neuro-oncology
- Surgical Oncology
- Biochemistry
Background:
- Fluorescence image-guided surgical resection (FIGR) for high-grade gliomas (HGGs) relies on protoporphyrin IX (PpIX) tracer accumulation.
- Insufficient PpIX fluorescence can compromise surgical precision and efficacy.
- Factors influencing PpIX signal variability in glioblastoma cells are not fully understood.
Purpose of the Study:
- To investigate factors that impair PpIX accumulation in glioblastoma cells.
- To identify pharmacological treatments that enhance PpIX fluorescence for improved FIGR.
- To understand the interplay of metabolic clearance and cellular efflux on PpIX levels.
Main Methods:
- Cultured U87 glioblastoma cell lines were used to assess PpIX accumulation under varying conditions (serum, confluence).
- Investigated the roles of ferrochelatase (FECH), heme oxygenase-1 (HO-1), and ATP-binding cassette subfamily G member 2 (ABCG2) in PpIX metabolism and efflux.
- Tested pharmacological modulators: genistein (ABCG2 inhibitor), deferoxamine (FECH modulator), and tin protoporphyrin IX (SnPP, HO-1 inhibitor).
Main Results:
- Cell culture serum and confluence levels negatively impact PpIX accumulation.
- Pharmacological inhibition of ABCG2, FECH, and HO-1 pathways can enhance PpIX accumulation.
- A combination of modulators effectively increased PpIX fluorescence in glioblastoma cells.
Conclusions:
- Serum presence and cellular confluence are identified as negative modulators of PpIX accumulation.
- Targeting metabolic clearance and efflux pathways offers a viable strategy to enhance PpIX fluorescence.
- Pharmacological enhancement of PpIX fluorescence holds promise for improving FIGR in HGGs and potentially low-grade gliomas (LGGs).
