Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P42574 (caspase-3)
 45,978 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cyclophosphamide (CPA), a widely used oxazaphosphorine anti-cancer prodrug, is inactive until it is metabolized by cytochrome P450 to yield phosphoramide mustard and acrolein, which alkylate DNA and proteins, respectively. Tumor cells transduced with the human cytochrome P450 gene CYP2B6 are greatly sensitized to CPA, however, the pathway of CPA-induced cell death is unknown. The present study investigates the cytotoxic events induced by CPA in 9L gliosarcoma cells retrovirally transduced with CYP2B6, or induced in wild-type 9L cells treated with mafosfamide (MFA) or 4-hydroperoxyifosfamide (4OOH-IFA), chemically activated forms of CPA and its isomer ifosfamide. CPA and MFA were both shown to effect tumor cell death by stimulating apoptosis, as evidenced by the induction of plasma membrane blebbing, DNA fragmentation, and cleavage of the caspase 3 and caspase 7 substrate poly(ADP-ribose) polymerase (PARP) in drug-treated cells. Caspase 9 was identified as the regulatory upstream caspase activated in 9L cells treated with CPA, MFA, or 4OOH-IFA, implicating the mitochondrial apoptotic pathway in oxazaphosphorine-induced tumor cell death. Correspondingly, expression of the mitochondrial proapoptotic factor Bax enhanced caspase 9 activation, plasma membrane blebbing, and drug-induced cytotoxicity. Conversely, overexpression of the mitochondrial antiapoptotic factor Bcl-2 blocked caspase 9 activation, leading to an inhibition of drug-induced plasma membrane permeability and blebbing, terminal deoxynucleotidyl transferase dUTP nick-end labeling positivity, PARP cleavage, Annexin V positivity, and drug-induced cell death. Although Bcl-2 thus blocked the cytotoxic effects of activated CPA, it did not inhibit the drug's cytostatic effects. CPA induced S-phase cell cycle arrest followed by conversion to an apoptotic pre-G1 state in wild-type 9L cells; by contrast, Bcl-2-expressing 9L cells accumulated in G2/M in response to CPA treatment. Intratumoral expression of Bcl-2 and related family members, including both apoptotic and antiapoptotic factors, is thus an important determinant of the responsiveness of tumor cells to CPA and ifosfamide, both in the context of conventional chemotherapy and in patients sensitized to these oxazaphosphorine drugs by the use of cytochrome P450-based gene therapy.
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PMID:Cyclophosphamide induces caspase 9-dependent apoptosis in 9L tumor cells. 1172 34

Higher cyclooxygenase-2 (COX-2) expression is clinically associated with more aggressive gliomas and is a strong predictor of poor survival. To determine whether oral administration of a COX-2-specific inhibitor can inhibit glial tumors, we analyzed the effect of celecoxib on the growth of 9L rat gliosarcoma cells that were orthotopically transplanted into rat brains. Oral administration of celecoxib beginning 1 day after implantation of 5 x 10(4) 9L rat gliosarcoma cells into rat brain reduced the incidence and size of tumors significantly. Immunohistochemical analysis of implanted gliosarcoma cells from rats treated with celecoxib showed lower levels of phospho-Akt, phospho-EGFR, Bcl-2, and Bcl-XL expression compared with untreated tumor cells. Gliosarcoma cells from treated rats had significantly more TUNEL- and caspase-3-positive cells and fewer PCNA-positive cells. These results demonstrate that selective COX-2 inhibitors may be useful as adjuvants and/or therapeutic agents to treat gliomas overexpressing COX-2.
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PMID:Intracranial inhibition of glioma cell growth by cyclooxygenase-2 inhibitor celecoxib. 1471 52

Therapeutic radiation and subsequent detection of tumor cell death has been performed mainly in vitro systems, making it difficult to accurately characterize the mechanisms of tumor cell death after radiosurgery. To better characterize what occurs to glioma cells after radiation therapy, we developed a rat model using the 9L gliosarcoma cell line implanted reproducibly to the caudate nucleus in rats. After 1 Gy radiation, 9L tumors in vivo induced mainly necrosis (determined by trypan blue exclusion) of 10 - 74 % at 6 - 72 hours post-radiation. This is in contrast to a previous in vitro study which demonstrated that 18 Gy of radiation induces considerably less cell death as determined by trypan blue exclusion (approximately 20 - 25 % at 6 - 72 hours post-radiation). However, significant amounts of apoptosis were detected as early as 6 hours after radiation. Apoptosis determination was by annexin V (marker of early apoptosis) and propidium iodide (marker of membrane stability) staining followed by flow cytometry detection. When caspase 3 and caspase 8 enzymatic activities (mediators of apoptosis) were measured from freshly explanted tumor cells, peak activity was found 6 hours after 1 Gy radiation (p < 0.01). Taken together, these data indicate the presence of apoptosis early after radiation therapy (1 Gy) which progressed to necrosis in a unique in vivo model of gliosarcoma that may prove useful in determining new therapeutic approaches to radiation therapy and tumor cell biology.
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PMID:Gliosarcoma cell death after radiosurgery in a rat model. 1601 90