Antipoliferative and apoptotic effect of ascorbyl strearate in human glioblastoma multifame cells; Modulations of insulin like growth factor receptor expression

Human glioblastomas (gliomas) are characterized as highly invasive and rapidly growing brain tumors. In this study,
we present data on in vitro effect of ascorbyl stearate (Asc-S), a liphophilic derivative of ascorbic acid on cell proliferation,
transformation, apoptosis and modulation of expression of insulin-like growth factor-I receptor (IGF-IR)
in human glioblastoma multiforme (T98G) cells. Asc-S showed significant inhibition of fetal bovine serum and
human recombinant insulin-like growth factor-I (IGF-I) dependent cell proliferation in a dose dependent manner.
Treatment of T98G cells with 0, 50, 100 and 150 μM Asc-S for 24 h slowed down the cell multiplication cycle
with significant accumulation of cells at late S/G2-M phase of cycle. Asc-S treatment (100 μM) reversed the transformed
phenotype as determined by clonogenecity in soft agar and also induced apoptosis of T98G. These changes
were found to be associated with significant decrease in IGF-IR expression in dose and time dependent manner
compared to untreated controls. The data clearly demonstrate that Asc-S has antiproliferative and apoptotic effect
on T98G cells probably through modulation of IGF-IR expression and consequent facilitation of programmed cell
death.