Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0376358 (prostate cancer)
 59,338 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Several oncogenes involved in prostate carcinogenesis activate mitogen-activated protein (MAP) kinases, which can relay both proliferative (via extracellular regulated kinases (ERK)) and apoptotic signals (via jun N-terminal protein kinases (JNK)) to the nucleus. Mitogen-activated protein kinase phosphatase 1 (MKP-1) is induced by several oncogenes in the ras-dependent pathway and can inactivate both MAP kinase pathways. The role of MKP-1 in proliferation and apoptosis is, however, still controversial. A series of 51 prostate cancers, including a subset (n = 13) that had been previously treated by androgen ablation, was used to examine whether MKP-1 mRNA and protein expression correlated with that of ERK-1, JNK-1, bcl-2, which confers resistance to apoptosis, and apoptotic index measured by in situ end-labeling of fragmented DNA. In a subset of tumors, MKP-1 expression was assessed by semiquantitative RT-PCR and was compared with both ERK-1 and JNK-1 enzymatic activity. In cases not treated by androgen ablation, MKP-1 was overexpressed in the preinvasive stage of prostate cancer, but its expression decreased with higher histologic grade and advanced disease stage. There was coexpression of MKP-1, ERK-1, and JNK-1 proteins. In addition, MKP-1 expression was inversely correlated to JNK-1 but not to ERK-1 enzymatic activity. Finally, MKP-1 and bcl-2 were inversely related to apoptotic indices. In cases treated by total androgen ablation, MKP-1 and bcl-2 were both down-regulated, whereas JNK-1 was up-regulated. Subpopulations of cells that did not undergo apoptosis maintained expression of both MKP-1 and bcl-2. These results suggest that MKP-1 overexpression is associated with the early phases of neoplastic transformation in prostate tissue. The enzymatic data on MKP-1 kinase substrates and the inverse correlation between MKP-1 and parameters of programmed cell death support the hypothesis that MKP-1 inhibits apoptosis in human prostate tumors, perhaps through the JNK pathway.
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PMID:Mitogen-activated protein kinase phosphatase 1 is overexpressed in prostate cancers and is inversely related to apoptosis. 901 Apr 48

Cytoplasmic phospholipase A2 (PLA2) is known to be phosphorylated and activated by MAP kinase (Lin et al 1993, Cell 72: 269-278), an important downstream component of signal transduction, whereas paclitaxel has been shown to inhibit isoprenylation of ras proteins (Danesi et al 1995, Mol Pharmacol 47: 1106-1111). Given that quinacrine (Q), a PLA2 inhibitor, and paclitaxel (P) might act at different sites in the cell signalling pathway, our aim was to test whether they were synergistic in combination against prostate cancer cells. Cell viability of PC-3, PC-3M and DU145 cells in 96 - well plates was assessed 96 h after drugs were added concurrently. Using Chou analysis, we demonstrated synergy for the combination against all three cell lines. Further, synergy was present under both conservative (mutually non-exclusive) and non-conservative (mutually exclusive) models. Studies in the nude mouse xenograft model support the finding of synergy in vitro. In DU145-bearing mice, Q (50 mg kg(-1)) and P (0.5 mg kg(-1)) given daily for 12 consecutive days, either concurrently or sequentially, was more effective than either drug alone, at twice the dose intensity. In an enzyme-linked immunosorbent (ELISA) apoptosis assay, arachidonic acid was able to partially reverse Q- and P-induced apoptosis, suggesting PLA2 pathway involvement. Finally, the combination of lovastatin, another inhibitor of ras isoprenylation, and quinacrine had synergistic inhibitory effects on the growth of PC-3 cells in vitro, suggesting that the combination of these two classes of compounds might serve as an attractive therapeutic approach for prostate cancer.
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PMID:Enhancement of paclitaxel activity against hormone-refractory prostate cancer cells in vitro and in vivo by quinacrine. 918 73

Both hyaluronidase and transforming growth factor (TGF)-beta 1 play a significant role in the development of prostate cancer. In this study, the regulation of tumor necrosis factor (TNF)-mediated cell death by hyaluronidase and TGF-beta 1 was investigated. Preexposure of L929 fibroblasts, prostate LNCaP cells, and epithelial Mv 1 Lu cells to hyaluronidase for a minimum of 12 h resulted in significant enhancement of cell death by TNF. Phosphorylation of p42 and p44 mitogen-activated-protein (MAP) kinases was found by stimulation of L929 cells with hyaluronidase for 30 min, indicating that the Raf/MAP kinase-extracellular signal-regulating protein kinase (MEK)/ MAP kinase pathway was activated. However, blocking the activation of upstream MAP kinase kinase (MEK 1 and 2 kinase) by PD-98059 failed to inhibit the hyaluronidase-enhanced TNF killing of cells, suggesting that hyaluronidase-mediated degradation of extracellular matrix and membrane components may elicit multiple signaling pathways. As a potent stimulator of extracellular matrix protein synthesis, TGF-beta 1 blocked the hyaluronidase-enhanced death of L929 and LNCaP cells mediated by TNF. TGF-beta 1 activated protein-tyrosine kinases in L929 cells, in which the tyrosine kinase inhibitors lavendustin A and tyrphostin blocked the activation as well as the TGF-beta 1 inhibition of hyaluronidase effects. Functional antagonism was also observed between hyaluronidase and TGF-beta 1 in cell growth regulation. For example, TGF-beta 1-mediated suppression of epithelial Mv 1 Lu cell growth was abolished by hyaluronidase. Overall, it is demonstrated in this study that hyaluronidase reciprocally antagonized TGF-beta 1 in the modulation of cell proliferation and TNF-mediated death.
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PMID:Hyaluronidase enhancement of TNF-mediated cell death is reversed by TGF-beta 1. 943 5

Interleukin-6 (IL-6) is a cytokine that was initially recognized as a regulator of immune and inflammatory responses, but it also regulates the growth of many tumour cells, including prostrate carcinoma. Overexpression of the growth-factor receptors ErbB2/neu and ErbB3 has been implicated in the neoplastic transformation of prostate carcinoma. Here we show that treatment of the prostate cancer cell line LNCaP with IL-6 induces tyrosine phosphorylation of ErbB2 and ErbB3, but not ErbB1/EGFR. We also show that ErbB2 forms a complex with the gp130 subunit of the IL-6 receptor in an IL-6-dependent manner. This association is important because the inhibition of ErbB2 activity results in abrogation of IL-6-induced MAPK activation. Thus ErbB2 is a critical component of IL-6 signalling through the MAP kinase pathway. These data show how a cytokine receptor can diversify its signalling pathways by engaging with a growth-factor receptor kinase.
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PMID:Requirement of ErbB2 for signalling by interleukin-6 in prostate carcinoma cells. 959 Jun 94

Mitogen-activated protein (MAP) kinases are key elements of the signalling systems needed to transduce different extracellular messages into cellular responses. At least three parallel MAP kinase pathways have been identified: one, stimulated by serum and growth factors to activate extracellular signal-regulated protein kinases (ERKs) by dual tyrosine and threonine phosphorylation, triggers cell proliferation or differentiation; the other two, induced by a variety of cellular stresses to activate c-jun N-terminal kinases (JNKs) and reactivating kinase (p38/RK), result in growth arrest and induction of apoptosis. Mitogen-activated protein kinase phosphatases (MKPs) inactivate MAP kinases through dephosphorylation and, thus, can modulate the MAP kinase pathways. Expression of JNK-1, ERK-1, p38/RK and MKP-1 proteins was investigated by immunohistochemistry and expression of MKP-1 mRNA by in situ hybridisation in 50 cases of high-grade prostatic intraepithelial neoplasia (PIN), thought to represent the precursor of prostate cancer. The frequency of apoptotic cells was also determined in these cases. Overexpression of the three MAP kinases and MKP-1 mRNA was found in all cases of high-grade PIN compared with normal prostate. Immunoreactivity for MKP-1 protein was found to be as intense as in normal glands in 30% and weaker in 56% of the PIN cases. Fourteen per cent of PIN cases did not stain with MKP-1 antibody. The proportion of apoptosis was significantly higher (P < 0.008) in PIN lesions that did not express MKP-1 protein than in those that did. These results are consistent with our previous demonstration of preferential inhibition of the apoptosis-related kinases by MKP-1 and further support the contention that MKP-1, even in PIN, may shift the balance existing between cell proliferation and death. When expressed, it may inhibiting those pathways that lead to apoptosis.
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PMID:Mitogen-activated protein kinases and apoptosis in PIN. 964 39

Using an antibody specific for dually phosphorylated extracellular-regulated kinases 1 and 2, we have examined 82 primary and metastatic prostate tumor specimens for the presence of activated mitogen-activated protein (MAP) kinase. Nonneoplastic prostate tissue showed little or no staining with activated MAP kinase antiserum. In prostate tumors, the level of activated MAP kinase increased with increasing Gleason score and tumor stage. In a separate analysis, tumor samples from two patients showed no activation of MAP kinase before androgen ablation therapy; however, following androgen ablation treatment, high levels of activated MAP kinase were detected in the recurrent tumors. Collectively, these data suggest an increase in the activation of the MAP kinase signal transduction pathway as prostate cancer progresses to a more advanced and androgen-independent disease.
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PMID:Activation of mitogen-activated protein kinase associated with prostate cancer progression. 992 31

Overexpression of the HER2/Neu protooncogene has been linked to the progression of breast cancer. Here we demonstrate that the growth of prostate cancer LNCaP cells can also be increased by the stable transfection of HER2/Neu. Using AG879, a HER2/Neu inhibitor, and PD98059, a MAP kinase inhibitor, as well as MAP kinase phosphatase-1 (MPK-1), in the transfection assay, we found that HER2/Neu could induce prostate-specific antigen (PSA), a marker for the progression of prostate cancer, through the MAP kinase pathway at a low androgen level. Reporter assays and mammalian two-hybrid assays further suggest this HER2/Neu-induced androgen receptor (AR) transactivation may function through the promotion of interaction between AR and AR coactivators, such as ARA70. Furthermore, we found this HER2/Neu --> MAP kinase --> AR-ARAs --> PSA pathway could not be blocked completely by hydroxyflutamide, an antiandrogen used in the treatment of prostate cancer. Together, these data provide a novel pathway from HER2/Neu to AR transactivation, and they may represent one of the reasons for the PSA re-elevation and hormone resistance during androgen ablation therapy in prostate cancer patients.
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PMID:From HER2/Neu signal cascade to androgen receptor and its coactivators: a novel pathway by induction of androgen target genes through MAP kinase in prostate cancer cells. 1031 5

Mitogen-activated protein (MAP) kinases phosphorylate the estrogen receptor and activate transcription from estrogen receptor-regulated genes. Here we examine potential interactions between the MAP kinase cascade and androgen receptor-mediated gene regulation. Specifically, we have studied the biological effects of mitogen-activated protein kinase kinase kinase 1 (MEKK1) expression in prostate cancer cells. Our findings demonstrate that expression of constitutively active MEKK1 induces apoptosis in androgen receptor-positive but not in androgen receptor-negative prostate cancer cells. Reconstitution of the androgen receptor signaling pathway in androgen receptor-negative prostate cancer cells restores MEKK1-induced apoptosis. MEKK1 also stimulates the transcriptional activity of the androgen receptor in the presence or absence of ligand, whereas a dominant negative mutant of MEKK1 impairs activation of the androgen receptor by androgen. These studies demonstrate an unanticipated link between MEKK1 and hormone receptor signaling and have implications for the molecular basis of hormone-independent prostate cancer growth.
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PMID:Mitogen-activated protein kinase kinase kinase 1 activates androgen receptor-dependent transcription and apoptosis in prostate cancer. 1037 63

In this report, a novel inhibitor of farnesyl protein transferase (FPTase) is described. The compound, XR3054, is structurally similar to farnesol, a component of the reaction in which FPTase catalyses transfer of farnesol pyrophosphate to the CAAX recognition motif on proteins. The compound was selected initially because of its ability to inhibit in vitro farnesylation of CAAX recognition peptides with an IC50 of 50 microM. The farnesylation of p21 ras was reduced in a dose-dependent manner in the presence of XR3054. Similarly XR3054 was able to reduce the anchorage-independent growth of V12 H-ras transformed NIH 3T3 cells in a focus formation assay in soft agar, with an IC50 value of 30 microM, whilst not affecting the anchorage-independent growth of v-raf transformed cells. XR3054 reduced the phosphorylation of p42 mitogen activated protein (MAP) kinase in parental NIH 3T3 cells and V12 H-ras transformed NIH 3T3 cells, but constitutively active v-raf transformed cells showed no reduction in phosphorylation of ERK2 in the presence of XR3054. XR3054 inhibited the proliferation of the prostatic cancer cell lines LnCAP and PC3 and the colon carcinoma SW480 and HT1080 (IC50 values of 12.4, 12.2, 21.4 and 8.8 microM, respectively) but was relatively inactive when tested against a panel of breast carcinoma cell lines. The activity did not relate to the presence of mutant or wild-type ras in the cell lines tested. In conclusion XR3054 inhibits ras farnesylation, MAP kinase activation and anchorage-independent growth in NIH 3T3 transformed with v12 H-ras. Since the antiproliferative effect of the compound is not related to the ras phenotype, XR3054 may also have effects on other cell signalling mechanisms.
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PMID:XR3054, structurally related to limonene, is a novel inhibitor of farnesyl protein transferase. 1053 87

Androgens are important growth regulators in prostate cancer. Their known mode of action in target cells requires binding to a cytoplasmic androgen receptor followed by a nuclear translocation event and modulation of the expression of specific genes. Here, we report another mode of action of this receptor. Treatment of androgen responsive prostate cancer cells with dihydrotestosterone leads to a rapid and reversible activation of mitogen-activated protein kinases MAPKs (also called extracellular signal-regulated kinases or Erks). Transient transfection assays demonstrated that the androgen receptor-mediated activation of MAP kinase results in enhanced activity of the transcription factor Elk-1. This action of the androgen receptor differs from its known transcriptional activity since it is rapid and insensitive to androgen antagonists such as hydroxyflutamide or casodex. Biochemical studies as well as analyses with dominant negative mutants showed the involvement of kinases such as MAPK/Erk kinase, phosphatidyl-inositol 3-kinase and protein kinase C in the androgen receptor-mediated activation of MAP kinase. These results demonstrate a novel regulatory action of the androgen receptor and prove that in addition to its known transcriptional effects, it also uses non-conventional means to modulate several cellular signalling processes.
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PMID:Rapid signalling by androgen receptor in prostate cancer cells. 1059 31


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