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The Subcellular Targets of
Mercaptoborate (BSH), a Carrier of 10B for Neutron
Capture Therapy (BNCT) of Brain Tumors
V. Mareš1,2, D. Krajčí3, V.
Lisá1
1Joint
Laboratory of Cancer Cell Biology of the Institute of
Physiology, Academy of Sciences and the First Faculty of
Medicine, Charles University, Prague, 2Chair of
Biology, Purkinje University, Ústí nad Labem, Czech Republic,
3Faculty of Medicine, Kuwait University, Department
of Anatomy, Safat, Kuwait City, State of Kuwait
Received August 22,
2002
Accepted October 5, 2002
Summary
The transformed C6 glial cells in cultures were treated with
sodium mercaptoborate (Na2B12H11SH, BSH), a carrier of atomic
targets (10B) of thermal neutrons for the neutron capture
therapy of brain tumors. As shown by light microscopy, the
therapeutic dose of BSH (100 µg/ml) did not alter the gross
morphology and growth of the population of cells within a 72 h
treatment interval. Electron microscopic analysis of these cells
revealed activation of nucleoli and, occasionally, enlarged and
bifurcated mitochondria. After 200 µg BSH/ml and 72 h treatment,
growth of the cell population was inhibited and ultrastructural
changes became more profound. They included condensation of
chromatin and its allocation to the nuclear envelope which
formed deeper invaginations. Mitochondria further increased in
size and were characterized by slim or angular cristae.
Moreover, in circumscribed segments of some of the slightly
swollen mitochondria their cristae disappeared or were reduced
to fine pouch-like structures localized near the continuous
outer membrane, suggestive for a non-destructive restructuring
of the inner mitochondrial membrane. The smooth pinocytotic
vesicles near the plasma membrane, lysosomes and heterogeneous
dense bodies were more frequent. The revealed subcellular
targets of BSH may initiate the development of pharmacological
protocols aimed to further improve the tolerance to BSH by the
healthy tissues of patients undergoing BNCT of brain tumors,
e.g. by intervention into the oxidative stress triggered likely
by the altered mitochondria.
Key words
Borocaptate (BSH) • Brain tumors • Mitochondria • Nucleus •
Neutron Capture Therapy (NCT)
Reprint requests
V. Mareš, M.D., D.Sc., Institute of Physiology, Academy of
Sciences, Vídeňská 1083, CZ-14200 Prague 4, Czech Republic.
E-mail:
maresv@biomed.cas.cz
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