Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.22.62 (caspase-9)
 7,507 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Dopamine (DA) agonists are the primary treatment choice for prolactinoma, effectively suppressing prolactin expression and reducing tumour size. However, the intracellular pathway(s) through which either DA or its agonists impact on proliferation or lead to tumour shrinkage are incompletely understood. To identify the mediators in the apoptotic cascades after DA or DA agonist challenges we used a well-characterized model system, the rodent somatolactotroph cell line GH3. In these cells, we show that apoptosis induced by the DA agonist bromocriptine (BC), but not DA, is initiated through activation of the JNK pathway. However, both DA and BC activate the terminal effector caspase, caspase-3. Kinetic studies and chemical inhibitor co-incubation experiments support a role for JNK activation preceding caspase-9 activation in BC challenged cells, however, engagement of these mediators was not apparent in DA challenge cells. These studies suggest that apoptosis induced by BC or DA is mediated through distinct and independent pathways that converge with activation of the terminal caspase, caspase-3. These observations were further reinforced by our findings that DA and BC, in co-incubation experiments, synergistically induce apoptosis. These findings raise the possibility that drugs acting through the same pathway as DA may be clinically beneficial when combined with BC.
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PMID:Bromocriptine and dopamine mediate independent and synergistic apoptotic pathways in pituitary cells. 2011 Jun 59

Prolactinomas are the most prevalent functional pituitary adenomas that cause chronic pathological hyperprolactinemia. Prolactin is known to promote cell growth and inhibit apoptosis in cells. Paeoniflorin is the principal component of radix Paeoniae alba (the main ingredient in some traditional herbal formulas clinically used for hyperprolactinemia-associated disorders). Recent findings from intensive studies have suggested that paeoniflorin regulates cell proliferation and apoptosis in many cell lines. However, the effects of paeoniflorin in pituitary tumor cells remain unknown. Here the results by the Cell Counting Kit-8 and colony formation assays showed that paeoniflorin concentration-dependently decreased cell viability in both MMQ and GH3 cells and colony formation in GH3 cells, suggesting inhibition of cell proliferation by paeoniflorin. By flow cytometry, paeoniflorin was found to increase apoptotic rate in MMQ cells. Mechanistically, Western blot results revealed that paeoniflorin enhanced protein expression of cleave caspase-9 and -3, and Bax, whereas it suppressed Bcl-2 protein expression in MMQ cells. Furthermore, paeoniflorin upregulated phosphorylated p53 protein expression, but it decreased prolactin concentration and prolactin protein expression in both MMQ and GH3 cells. Thus, the present results demonstrate that paeoniflorin inhibits cell proliferation and induces the mitochondrial pathway-mediated apoptosis in prolactinoma cells. These antitumor property is associated with inhibition of prolactin secretion. Our findings may provide new insight into the mechanisms underlying improving prolactinoma-associated disorders of paeoniflorin-enriched herbs and formulas.
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PMID:The prolactin-release inhibitor paeoniflorin suppresses proliferation and induces apoptosis in prolactinoma cells via the mitochondria-dependent pathway. 2938 11