Journal of neuro-oncology
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Journal of neuro-oncology · Oct 2015
Dynamic contrast enhanced T1 MRI perfusion differentiates pseudoprogression from recurrent glioblastoma.
Pseudoprogression may present as transient new or increasing enhancing lesions that mimic recurrent tumors in treated glioblastoma. The purpose of this study was to examine the utility of dynamic contrast enhanced T1 magnetic resonance imaging (DCE MRI) in differentiating between pseudoprogression and tumor progression and devise a cut-off value sensitive for pseudoprogression. We retrospectively examined 37 patients with glioblastoma treated with radiation and temozolomide after surgical resection that then developed new or increasing enhancing lesion(s) indeterminate for pseudoprogression versus progression. ⋯ Ktrans (mean) of >3.6 had a 69% sensitivity and 79% specificity for disease progression. DCE MRI shows lower plasma volume and time dependent leakage constant values in pseudoprogression than in tumor progression. A cut-off value with high sensitivity for pseudoprogression can be applied to aid in interpretation of DCE MRI.
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Journal of neuro-oncology · Oct 2015
Specific inhibition of mTOR pathway induces anti-proliferative effect and decreases the hormone secretion in cultured pituitary adenoma cells.
There are some evidences that pituitary tumors may be sensitive to the anti-proliferative effects of mammalian target of rapamycin (mTOR) inhibitors, while the mechanism and effects remains unclear, it is necessary to find if a specific mTOR inhibition, including the blocking of both mTOR function and expression, generate any effects on pituitary adenoma cells. The object of this study was to examine if specific inhibition of mTOR induced anti-proliferative effect and decreased the GH and PRL hormones secretion in GH3 and MtT/E pituitary adenoma cells by using a kind of mTOR shRNA lentiviral vector. The in vitro experiments results showed mTOR shRNA transfection robustly reduced the GH3 and MtT/E cells viability in all durations (1-6 days) we performed, also specifically decreased both GH and PRL hormones external secretion in GH3 cells. ⋯ In addition, we examined in vitro effects of PA treatment and mTOR shRNA gene transfection on major proteins expressed in the mTOR pathway in GH3 cells, and confirmed that PA treatment significant increased the protein levels of pmTOR, pS6 K and p4EBP1 in the scramble shRNA group, while the increase of protein levels was blocked by mTOR shRNA gene transfection. Moreover, mTOR shRNA gene transfection definitely inhibited the expression of mTOR and reduced the expression of pmTOR, pS6K and p4EBP1 in either PA or no PA treatment groups. These findings indicated that specific inhibition of mTOR pathway induced anti-proliferative effect and decreased the GH and PRL hormones secretion in cultured pituitary adenoma cells, which may be a novel promising and potential treatment modality for patients with secreting or non-secreting pituitary adenomas.