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)

Arginine deprivation as an anticancer therapy has historically been met with limited success. The development of pegylated arginine deiminase (ADI-PEG20) has renewed interest in arginine deprivation for the treatment of some cancers. The efficacy of ADI-PEG20 is directly correlated with argininosuccinate synthetase (ASS) deficiency. CWR22Rv1 prostate cancer cells do not express ASS, the rate-limiting enzyme in arginine synthesis, and are susceptible to ADI-PEG20 in vitro. Interestingly, apoptosis by 0.3 microg/mL ADI-PEG20 occurs 96 hours posttreatment and is caspase independent. The effect of ADI-PEG20 in vivo reveals reduced tumor activity by micropositron emission tomography as well as reduced tumor growth as a monotherapy and in combination with docetaxel against CWR22Rv1 mouse xenografts. In addition, we show autophagy is induced by single amino acid depletion by ADI-PEG20. Here, autophagy is an early event that is detected within 1 to 4 hours of 0.3 microg/mL ADI-PEG20 treatment and is an initial protective response to ADI-PEG20 in CWR22Rv1 cells. Significantly, the inhibition of autophagy by chloroquine and Beclin1 siRNA knockdown enhances and accelerates ADI-PEG20-induced cell death. PC3 cells, which express reduced ASS, also undergo autophagy and are responsive to autophagy inhibition and ADI-PEG20 treatment. In contrast, LNCaP cells highly express ASS and are therefore resistant to both ADI-PEG20 and autophagic inhibition. These data point to an interrelationship among ASS deficiency, autophagy, and cell death by ADI-PEG20. Finally, a tissue microarray of 88 prostate tumor samples lacked expression of ASS, indicating ADI-PEG20 is a potential novel therapy for the treatment of prostate cancer
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PMID:Arginine deiminase as a novel therapy for prostate cancer induces autophagy and caspase-independent apoptosis. 1914 87

Prostate cancer, the leading incidence of cancer in American males, is a disease in which treatment of nonlocalized tumors remains largely unsuccessful. These cancers lose expression of an arginine synthesis enzyme, argininosuccinate synthetase (ASS), and are susceptible to arginine deprivation by arginine deiminase (ADI). We show CWR22Rv1 prostate cancer cells are susceptible to ADI in a caspase-independent manner in vitro and in a xenograft model in vivo. We demonstrate that single amino acid deprivation by ADI is able to trigger autophagy. Inhibition of autophagy by chloroquine and siRNA enhances and accelerates ADI-induced cell death, suggesting that autophagy is a protective response to ADI, at least in the early phases. In addition, the co-administration of docetaxel, a caspase-dependent chemotherapy, with ADI inhibits tumor growth in vivo. Thus, targeting multiple cell death pathways, either through autophagy modulation or non-canonical apoptosis, may find expanded use as adjuvant chemotherapies, providing additional avenues for cancer treatment.
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PMID:ADI, autophagy and apoptosis: metabolic stress as a therapeutic option for prostate cancer. 1927 47

Prostate cancer is the leading form of malignancies among men in the U.S. While surgery carries a significant risk of impotence and incontinence, traditional chemotherapeutic approaches have been largely unsuccessful. Hormone therapy is effective at early stage, but often fails with the eventual development of hormone-refractory tumors. We have been interested in developing therapeutics targeting specific metabolic deficiency of tumor cells. We recently showed that prostate tumor cells specifically lack an enzyme (argininosuccinate synthase, or ASS) involved in the synthesis of the amino acid arginine(1). This condition causes the tumor cells to become dependent on exogenous arginine, and they undergo metabolic stress when free arginine is depleted by arginine deiminase (ADI)(1,10). Indeed, we have shown that human prostate cancer cells CWR22Rv1 are effectively killed by ADI with caspase-independent apoptosis and aggressive autophagy (or macroautophagy)(1,2,3). Autophagy is an evolutionarily-conserved process that allows cells to metabolize unwanted proteins by lysosomal breakdown during nutritional starvation(4,5). Although the essential components of this pathway are well-characterized(6,7,8,9), many aspects of the molecular mechanism are still unclear - in particular, what is the role of autophagy in the death-response of prostate cancer cells after ADI treatment? In order to address this question, we required an experimental method to measure the level and extent of autophagic response in cells - and since there are no known molecular markers that can accurately track this process, we chose to develop an imaging-based approach, using quantitative 3D fluorescence microscopy(11,12). Using CWR22Rv1 cells specifically-labeled with fluorescent probes for autophagosomes and lysosomes, we show that 3D image stacks acquired with either widefield deconvolution microscopy (and later, with super-resolution, structured-illumination microscopy) can clearly capture the early stages of autophagy induction. With commercially available digital image analysis applications, we can readily obtain statistical information about autophagosome and lysosome number, size, distribution, and degree of colocalization from any imaged cell. This information allows us to precisely track the progress of autophagy in living cells and enables our continued investigation into the role of autophagy in cancer chemotherapy.
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PMID:Quantitative analysis of autophagy using advanced 3D fluorescence microscopy. 2366 32

Autophagy is the principal catabolic prosurvival pathway during nutritional starvation. However, excessive autophagy could be cytotoxic, contributing to cell death, but its mechanism remains elusive. Arginine starvation has emerged as a potential therapy for several types of cancers, owing to their tumor-selective deficiency of the arginine metabolism. We demonstrated here that arginine depletion by arginine deiminase induces a cytotoxic autophagy in argininosuccinate synthetase (ASS1)-deficient prostate cancer cells. Advanced microscopic analyses of arginine-deprived dying cells revealed a novel phenotype with giant autophagosome formation, nucleus membrane rupture, and histone-associated DNA leakage encaptured by autophagosomes, which we shall refer to as chromatin autophagy, or chromatophagy. In addition, nuclear inner membrane (lamin A/C) underwent localized rearrangement and outer membrane (NUP98) partially fused with autophagosome membrane. Further analysis showed that prolonged arginine depletion impaired mitochondrial oxidative phosphorylation function and depolarized mitochondrial membrane potential. Thus, reactive oxygen species (ROS) production significantly increased in both cytosolic and mitochondrial fractions, presumably leading to DNA damage accumulation. Addition of ROS scavenger N-acetyl cysteine or knockdown of ATG5 or BECLIN1 attenuated the chromatophagy phenotype. Our data uncover an atypical autophagy-related death pathway and suggest that mitochondrial damage is central to linking arginine starvation and chromatophagy in two distinct cellular compartments.
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PMID:Arginine starvation-associated atypical cellular death involves mitochondrial dysfunction, nuclear DNA leakage, and chromatin autophagy. 2522 74