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)

The unresponsiveness of metastatic melanoma to conventional chemotherapeutic and biological agents is largely due to the development of resistance to apoptosis. Pyrimethamine belongs to the group of antifolate drugs, and in addition to antiprotozoan effects, it exerts a strong proapoptotic activity, which we recently characterized in human T lymphocytes. However, no data regarding pyrimethamine anticancer activity are available thus far. To this end, we examined the in vitro effects of pyrimethamine on apoptosis, cell cycle distribution, and cell proliferation of human metastatic melanoma cell lines. The in vivo antitumor potential of pyrimethamine was evaluated in a severe combined immunodeficiency (SCID) mouse xenotransplantation model. Our data indicate that pyrimethamine, when used at a clinically relevant concentration, induced apoptosis in metastatic melanoma cells via the activation of the cathepsin B and the caspase cascade (i.e., caspase-8 and caspase-9) and subsequent mitochondrial depolarization. This occurred independently from CD95/Fas engagement. Moreover, pyrimethamine induced a marked inhibition of cell growth and an S-phase cell cycle arrest. Results obtained in SCID mice, injected s.c. with metastatic melanoma cells and treated with pyrimethamine, indicated a significant inhibitory effect on tumor growth. In conclusion, our results suggest that pyrimethamine-induced apoptosis may be considered as a multifaceted process, in which different inducers or regulators of apoptosis are simultaneously implicated, thus permitting death defects of melanoma cells to be bypassed or overcome. On these bases, we hypothesize that pyrimethamine could represent an interesting candidate for the treatment of metastatic melanoma.
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PMID:Pyrimethamine induces apoptosis of melanoma cells via a caspase and cathepsin double-edged mechanism. 1859 30

Pyrimethamine has been used principally to treat infections from protozoan parasites. Although previous studies have shown that pyrimethamine exhibited anticancer activity by inducing cellular apoptosis, there are none that show that pyrimethamine possesses anticancer activity with respect to ovarian cancer. We examined the roles of pyrimethamine on apoptosis and proliferation, DNA damage, and cell cycle distribution of human ovarian cancer cell lines in vitro. To investigate the antitumor efficacy of pyrimethamine in vivo, we established two intraperitoneal ovarian carcinoma models in nude mice. Pyrimethamine significantly induced apoptosis of ovarian cancer cells via growth inhibition, cell cycle arrest, and nuclear DNA damage in vitro and manifested antitumor activity by inhibiting tumor growth, thereby prolonging the survival time of tumor-bearing mice. We also demonstrated that pyrimethamine increased the expression of caspase-9 and decreased the expression of X-linked inhibitor of apoptosis protein. In conclusion, the antitumor effects of pyrimethamine were associated with enhanced apoptosis of tumor cells and inhibition of the growth of intratumoral microvessels. Our results indicate that pyrimethamine may provide an effective approach toward inhibiting the growth of ovarian cancer with minimal adverse effects.
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PMID:Pyrimethamine exerts significant antitumor effects on human ovarian cancer cells both in vitro and in vivo. 3061 34