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Dysregulation of the phosphatidylinositol 3-kinase (PI3K) signaling pathway occurs frequently in human cancer. PTEN tumor suppressor or PIK3CA oncogene mutations both direct PI3K-dependent tumorigenesis largely through activation of the AKT/PKB kinase. However, here we show through phosphoprotein profiling and functional genomic studies that many PIK3CA(More)
NF-kappa B is a heterodimeric transcription activator consisting of the DNA binding subunit p50 and the transactivation subunit p65/RelA. NF-kappa B prevents cell death caused by tumor necrosis factor (TNF) and other genotoxic insults by directly inducing antiapoptotic target genes. We report here that the tumor suppressor PTEN, which functions as a(More)
Transformation and malignant progression of prostate cancer is regulated by the inability of prostatic epithelial cells to undergo apoptosis rather than by increased cell proliferation. The basic apoptotic machinery of most prostate cancer cells is intact and the inability to undergo apoptosis is due to molecular alterations that result in failure to(More)
Despite distinct dissimilarities, diverse cancers express several common protumorigenic traits. We present here evidence that the proapoptotic protein Par-4 utilizes one such common tumorigenic trait to become selectively activated and induce apoptosis in cancer cells. Elevated protein kinase A (PKA) activity noted in cancer cells activated the apoptotic(More)
The serine/threonine kinase AKT functions as a critical mediator of signaling downstream of PI3 kinase. Studies over the last two decades have firmly established the importance of AKT in the regulation of cell survival, proliferation, and insulin-dependent metabolic cell responses. AKT executes these diverse tasks through phosphorylation of numerous(More)
Prostate cancer cells are generally resistant to apoptosis by conventional therapy. During a search for molecules that may overcome prostate cancer cell survival mechanisms, we identified the prostate apoptosis response-4 (Par-4) gene. Par-4 induced apoptosis of selective prostate cancer cells PC-3, DU-145, and TSU-Pr and caused tumor regression by(More)
Ras is one of the most commonly mutated oncogenes in the array of human cancers. The mechanism by which Ras induces cellular transformation is, however, not fully elucidated. We present here evidence that oncogenic Ras suppresses the expression of the tumor suppressor phosphatase and tensin homologue deleted from chromosome 10 (PTEN), and this action of(More)
Oncogenic Ras causes down-regulation of the proapoptotic tumor suppressor gene Par-4. Replenishment of the basal levels of Par-4 results in inhibition of Ras-inducible cellular transformation. Moreover, overexpression of Par-4 (twofold to fourfold over basal levels) results in apoptosis of cells expressing oncogenic Ras. Par-4 does not, on its own, induce(More)
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