Effect of temozolomide on cell viability in gonadotroph adenoma cell lines

Abstract

Abstract. Invasive pituitary adenomas are usually refractory to routine neurosurgery, radiosurgery or medications, and alternative therapies are needed. The effects of temozolomide (TMZ) on the inhibition of gonadotroph adenoma cell viability and hormone secretion were evaluated. Cell viability and IC 50 values were evaluated after αT3-1 cells were treated with TMZ (31.25-1000 µM) or vehicle for 0-72 h. Cell cycle changes and the extent of apoptosis were detected using flow cytometry, TUNEL and TEM. The molecular mechanism of TMZ action was investigated by the Caspase-Glo ® assay and immunoblotting. Gonadotropin secretion was assessed using an immunoassay system. TMZ dose-and time-dependently suppressed cell proliferation (P<0.01 vs. control, 250 µM, 24 h) and induced S-phase accumulation and G2/M-phase arrest (P<0.05 vs. control, 250 µM, 24 h). Early apoptotic cells increased following a 24-h TMZ incubation (P<0.001 vs. control, 250 µM), consistent with TEM and TUNEL detection that exhibited morphological features of apoptosis. TMZ (250 µM) increased the level of caspase-3/7 by 6-fold, caspase-9 by 7-fold and caspase-8 by 3-fold after a 24-h incubation, while it attenuated Bcl-2 expression (P<0.001 vs.control) and raised the proteolysis of PARP. Both FSH and LH levels were significantly decreased by TMZ (P<0.01 vs. control, 250 µM, 24 h). TMZ inhibited cell proliferation and hormone secretion, and induced cell cycle arrest and apoptotic cell death in gonadotroph adenoma cells via both death receptor and mitochondrial pathways, suggesting that it may represent a useful medical management strategy of invasive gonadotroph adenomas.

Antitumor effects of pristimerin on human osteosarcoma cells in vitro and in vivo

“…The activity of caspases 3/7, 8, and 9 was assessed using the Caspase-Glo 3/7, 8, and 9 Assay (Promega). Experiments were conducted according to Ma et al 17 Caspase 3 activity was measured 12 h after PM treatment. Caspases 8 and 9 most likely act upstream of caspase 3; therefore, their activity was measured 8 h after PM treatment.…”

The PI3K/AKT/mTOR pathway in the pathophysiology and treatment of pituitary adenomas

“…One such dual-inhibitor known as XL765 used in combination with temozolomide (TMZ), an orally available alkylating agent previously shown to be effective at reducing PA cell viability (Ma et al 2011, Sheehan et al 2011, synergistically inhibited the proliferation of aT3-1, MMQ, and GH3 PA cell lines (Dai et al 2013).…”

Temozolomide is additive with cytotoxic effect of irradiation in canine glioma cell lines

“…A schedule‐dependent (temozolomide added before or after irradiation) effect of combined treatment as described in human cell lines was not detected in J3T‐BG cell line. (Chalmers et al., 2009 ) We chose the 24 h pre‐incubation with temozolomide in clonogenic assay experiments temozolomide as previous studies with human cancer cell lines showed this incubation time was optimal time to see the inhibitory effect (Ma et al., 2011 ; Mirabdaly et al., 2020 ). Moreover, we observed that when temozolomide was not removed from the cells after 24 h incubation (like in proliferation assay), no clones were formed in the temozolomide‐treated plates.…”