Although
meningiomas are one of the most common
tumors in the central nervous system, the adjuvant treatment for recurrent or
malignant meningiomas is not satisfactory. An intense interest in evaluating new molecular markers that may serve as potential therapeutic targets exists. Changes in apoptosis mechanisms play important roles in
tumor pathogenesis. One
pro-apoptotic protein is Smac/DIABLO, which neutralizes the inhibitors of apoptosis (IAPs). As Smac/DIABLO has not been previously analyzed in
meningiomas, We investigated the expression of Smac/DIABLO and
survivin in primary
meningioma cultures in vivo and in vitro. Expression of Smac/DIABLO,
survivin and single-stranded (ss)
DNA in vivo were determined immunohistochemically in 100
meningioma surgical specimens, dura and normal human cortex. The expression of the apoptotic
enzymes in vitro was analyzed after
RNA and
protein isolation of all
meningiomas via Western blotting and PCR. All examined
meningiomas and normal cerebral cortex displayed intense positive cytoplasmic Smac/DIABLO immunoreactivity.
Survivin and ssDNA were expressed in all surgical specimens and showed weak staining overall. Examination of Smac/DIABLO
protein via Western blotting showed distinct signals in the cytoplasmic extracts. PCR analysis displayed no changes of Smac/DIABLO and
survivin expression in different
meningioma grades, normal human cortical cortex or dura. Constant high-level Smac/DIABLO respectively low-level
survivin expression in
meningiomas and normal brain demonstrate similar apoptotic behavior of
meningiomas compared to normal brain tissue. These findings indicate no pathological overexpression of
survivin in
meningiomas as is evident in several other
cancer types impeding apoptosis.