cytochrome-c-t and Pituitary-Neoplasms

The purpose of this study was to investigate antitumour effects of liquiritigenin (LQ) on pituitary adenoma in in-vitro and in-vivo models.. The effects of LQ on cell viability, apoptosis rate, mitochondrial membrane potential (MMP), intracellular reactive oxygen species (ROS) level and various apoptosis-related mediators were examined in MMQ and GH3 cells that are derived from rat pituitary adenoma. Antitumour effect of LQ was also examined in the mouse model of GH3-xenografted tumour.. LQ inhibited cell viability, caused G1 phase arrest and initiated apoptosis in both MMQ and GH3 cells. LQ dissipated MMP, increased intracellular ROS level and cytosol cytochrome C, and reduced the expression of Ras, B-cell lymphoma 2 and B-cell lymphoma-extra large. LQ also inhibited the activation of extracellular signalling-regulated kinases (ERKs) and the translocation of from cytoplasm to nucleus. LQ markedly reduced tumour size without affecting bodyweight in mice with GH3 cells xenograft.. LQ effectively inhibits pituitary adenoma tumour growth and induces cell apoptotic death mainly via Ras/ERKs and ROS-dependent mitochondrial pathways, suggesting that LQ is a potential suppressor of pituitary adenoma.

Topics: Animals; Antineoplastic Agents, Phytogenic; Biological Transport; Cytochromes c; Extracellular Signal-Regulated MAP Kinases; Flavanones; Membrane Potential, Mitochondrial; Mitochondria; Mitogen-Activated Protein Kinases; Phytotherapy; Pituitary Neoplasms; Plant Extracts; Rats; Reactive Oxygen Species; Signal Transduction; Xenograft Model Antitumor Assays

Invasive pituitary adenomas (PAs) are generally refractory to conventional therapy and salvage treatment with temozolomide (TMZ). In addition to antiprotozoan effects, pyrimethamine (PYR) has recently shown its strong antitumor activity as an antineoplastic agent or in combination with TMZ in metastatic melanoma cells. In this study, the effects of TMZ, PYR or TMZ/PYR combination on rat/mouse PA cell lines αT3-1, GH3, MMQ and ATt-20 as well as GH3 xenograft tumor model were evaluated. TMZ/PYR combination synergistically inhibited proliferation, invasion and induced apoptosis of these PA cell lines in vitro. Strikingly, combination treatment with TMZ and PYR produced synergistic antitumor activity and enhanced the survival rate of GH3 xenograft tumor models without increasing systemic side effects. In addition, TMZ/PYR induced cell cycle arrest, increased DNA damage, upregulated the expression of cathepsin B, BAX, cleaved PARP and phosphorylated histone H2AX as well as elevated caspase3/7, 8 and 9 activities. The decreased expression of Bcl-2, MMP-2 and MMP-9 alone with cytochrome c release from mitochondria into the cytosol was also observed in the TMZ/PYR combination group. The increase in cell apoptosis due to combination with PYR was rescued by leucovorin. These data suggest that PYR may enhance the efficacy of TMZ via triggering both cathepsin B-dependent and caspase-dependent apoptotic pathways. Therefore, combination of PYR and TMZ may provide a novel regimen for invasive PAs refractory to standard therapy and TMZ.

Topics: Animals; Antineoplastic Agents, Alkylating; Apoptosis; bcl-2-Associated X Protein; Caspase 3; Caspase 7; Caspase 9; Cathepsin B; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Proliferation; Cytochromes c; Dacarbazine; DNA Damage; Drug Synergism; Female; Folic Acid Antagonists; Histones; Leucovorin; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Mice; Mice, Inbred NOD; Mice, SCID; Mitochondria; Neoplasm Invasiveness; Neoplasm Transplantation; Phosphorylation; Pituitary Neoplasms; Poly (ADP-Ribose) Polymerase-1; Poly(ADP-ribose) Polymerases; Proto-Oncogene Proteins c-bcl-2; Pyrimethamine; Rats; Temozolomide; Up-Regulation; Xenograft Model Antitumor Assays

Magmas is a nuclear gene that encodes for the mitochondrial import inner membrane translocase subunit Tim16. Magmas is overexpressed in the majority of human pituitary adenomas and in a mouse ACTH-secreting pituitary adenoma cell line. Here we report that Magmas is highly expressed in two out of four rat pituitary adenoma cell lines and its expression levels inversely correlate to the extent of cellular response to staurosporine in terms of apoptosis activation and cell viability. Magmas over-expression in rat GH/PRL-secreting pituitary adenoma GH4C1 cells leads to an increase in cell viability and to a reduction in staurosporine-induced apoptosis and DNA fragmentation, in parallel with the increase in Magmas protein expression. These results indicate that Magmas plays a pivotal role in response to pro-apoptotic stimuli and confirm and extend the finding that Magmas protects pituitary cells from staurosporine-induced apoptosis, suggesting its possible involvement in pituitary adenoma development.

Topics: Adenoma; Animals; Apoptosis; Caspase 3; Caspase 7; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cytochromes c; Enzyme Activation; Gene Expression; Membrane Transport Proteins; Mitochondria; Mitochondrial Proteins; Pituitary Neoplasms; Rats; Staurosporine