Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Dibutyryl cyclic AMP (DBcAMP) was previously reported to enhance the down-regulation of the retinoblastoma (RB) protein during G1 phase in proliferating primary rat hepatocytes, but to inhibit their entry into S phase and RB phosphorylation. In the present study, DBcAMP was also found to enhance the down-regulation of RB protein in the human hepatoma cells PLC/PRF/5 after hydroxyurea-induced synchronization at G1/S phase. One hour after synchronization, CPP32 activity was detected in the cells and was further enhanced in the presence of DBcAMP. CPP32-specific cleavage of the RB protein was also detected and enhanced by the addition of DBcAMP in a dose-dependent manner. DNA analysis by flow cytometry after serum starvation-induced synchronization at G0/G1 phase revealed that DBcAMP elicited an apoptotic peak after the S phase. Based on these findings, DBcAMP was suspected of inducing apoptosis by RB protein degradation during G1/S transition and thereby inhibit the growth of PLC/PRF/5 cells. Under serum-deficient culture conditions, addition of the CPP32 inhibitor DEVD or the ICE inhibitor YVAD enhanced cell growth but did not abolish the DBcAMP-induced growth inhibition. On the other hand, antisense oligodeoxynucleotides against Bcl-2 mRNA showed a growth inhibitory effect on PLC/PRF/5 cells, but did not show an additive effect on the DBcAMP-induced growth inhibition. DBcAMP itself inhibited bcl-2 protein expression. DBcAMP-induced growth inhibition may be mediated by different mechanisms, including apoptosis.
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PMID:Dibutyryl cyclic AMP-induced enhancement of RB protein degradation in human hepatoma cells. 1069 31

The antiproliferative effect of human bcl-2 gene transferred to E1A + c-Ha-ras-transformed rat embryo fibroblasts, which are characterized by the absence of cell cycle checkpoints after damage and by a high proapoptotic sensitivity was studied. Ionizing irradiation, adriamycin treatment, and serum starvation were shown to induce G1/S arrest in E1A + c-Ha-ras-transformants. Bcl-2 antiproliferative effect in E1A + c-Ha-ras-transformants was not associated with alterations in Cdk2, cyclin E and A contents. G1/S arrest following irradiation or serum starvation was accompanied by a decrease in kinase activity associated with cyclin E-cdk2, whereas G1/S arrest in tetraploid subpopulation after adriamycin treatment did not correlate with a decrease in cyclin E-associated kinase activity. Cyclin A-associated kinase activity did not decrease after any used treatment. Transfection of bcl-2 in E1A + c-Ha-ras-transformants resulted in elevated expression of cyclin-cdk complexes inhibitor p21/Waf-1, but not p27/Kip. Damaging agents caused p21/Waf-1 and p27/Kip accumulation, but bcl-2 overexpression did not restore functions of these inhibitors, since p21/Waf-1 and p27/Kip were unable to suppress cyclin-cdk complexes activity after damage. These results suggest that bcl-2 transfection in E1A + c-Ha-ras-transformants is likely to result in irradiation- or serum starvation-induced G1/S arrest accomplished by a selective decrease in cyclin E-associated kinase activity. Adriamycin-induced G1/S arrest seems to be realized via cyclin-cdk complexes activity-independent way involving antiproliferative targets downstream of cyclin E-cdk2 and cyclin A-cdk2 complexes.
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PMID:[Changes in the activity of cyclin-kinase complexes governing cell transition from G1 phase to DNA replication phase in E1A + c-Ha-ras transformants transfected with the bcl-2 gene]. 1272 79

1. In the present study, we describe the expression of the neuropeptides vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating polypeptide (PACAP) as well as their receptors in PC-3 cells, a human prostate cancer cell line. In addition, we have investigated their role in apoptosis induced by serum starvation. 2. By RT-PCR and immunocytochemistry assays, we have demonstrated the production of VIP and PACAP in PC-3 cells. 3. We have demonstrated by RT-PCR and binding assays the expression of common PACAP/VIP (VPAC(1) and VPAC(2)) receptors, but not PACAP-specific (PAC(1)) receptors. The pharmacological profile of [(125)I]-VIP binding assays was as follows: VPAC(1) antagonist=VPAC(1) agonist>VIP>VPAC(2) agonist (IC(50)=1.2, 1.5, 2.3 and 30 nM, respectively). In addition, both receptor subtypes are functional since VIP, PACAP-27 or VPAC(1) and VPAC(2) agonists all increased the intracellular levels of cAMP. 4. The expression of both peptides and their receptors is similar in serum-cultured and serum-deprived PC-3 cells. The treatment of serum-deprived PC-3 cells with exogenous VIP or PACAP-27 increases cell number and viability in a dose-dependent manner, as demonstrated by cellular counting and MTT assays. The increased cell survival is exerted through the VPAC(1) receptor, since a VPAC(1), but not VPAC(2), receptor agonist, mimics the effects and a VPAC(1) receptor antagonist blocks it. Moreover, VIP and PACAP-27 inhibit genomic DNA fragmentation in PC-3 cells triggered by serum starvation, and increase the immunoreactivity of the antiapoptotic protein bcl-2. 5. Our results suggest that VIP and PACAP are autocrine/paracrine factors that protect PC-3 cells from apoptosis through VPAC1 receptors.
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PMID:VIP and PACAP are autocrine factors that protect the androgen-independent prostate cancer cell line PC-3 from apoptosis induced by serum withdrawal. 1283 80

Protein kinase C (PKC) is a multigene family consisting of at least 11 isoforms that play key roles in growth control and tumorigenesis. To understand the roles of specific isoforms of PKC in breast cancer, we generated derivatives of the human breast cancer cell line MCF-7 that stably overexpress dominant negative mutants (REG) of PKC-alpha, -epsilon, or -zeta, which encode only the regulatory domains of the respective isoforms. When stimulated to re-enter the cell cycle after serum starvation, the MCF-7/PKC-alpha-REG cell line exhibited enhanced cell-cycle progression in comparison to the control cell line. These cells also showed increased sensitivity to growth inhibition and induction of apoptosis in response to various cytotoxic stimuli, including serum starvation, tamoxifen, and gamma-radiation. Western blot analysis indicated that the MCF-7/PKC-alpha-REG cell line displayed marked decreases in the levels of the cyclin-dependent kinase inhibitor p21CIP1 and the anti-apoptotic protein bcl-2. Similar, but less striking, effects were seen in the MCF-7/PKC-epsilon-REG cell line, and the MCF-7/PKC-zeta-REG cell line showed minimal changes, when compared to the control cells. Taken together, these results suggest that the endogenous PKC-alpha in MCF-7 cells plays a critical role in regulating cell-cycle control and apoptosis, in part through upregulating the expression of p21CIP1 and bcl-2. Therefore, inhibitors of PKC-alpha may potentiate the activity of cytotoxic agents in the therapy of breast cancer.
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PMID:Effects of regulatory domains of specific isoforms of protein kinase C on growth control and apoptosis in MCF-7 breast cancer cells. 1464 18

Transformed rat embryo fibroblasts E1A + cHa-ras known to possess high proapoptotic sensitivity and not to be arrested after DNA damage or upon serum starvation, were transfected with bcl-2 gene using calcium-phosphate precipitation method. Triple transformants E1A + cHa-ras + bcl-2 appeared to be protected from damage- and serum depletion-induced apoptosis and to restore cell cycle checkpoint control. Using the method of flow cytometry we have shown that these transformants are arrested in different phases of cell cycle in response to irradiation, adriamycin treatment and serum deprivation. Overexpression of bcl-2 in E1A + cHa-ras-transformed cells entirely suppresses adriamycin-induced apoptosis and significantly reduces the level of apoptosis triggered by irradiation and growth factor withdrawal, as we have revealed by the test of clonogenic survival and electrophoretic analysis of oligonucleosomal DNA fragmentation. Our results have demonstrated, for the first time, that the oncogenic Ras co-immunoprecipitates with transfected Bcl-2 in E1A + cHa-ras + bcl-2 transformed cells after irradiation but not after adriamycin treatment. Bcl-2-Ras complexes were also observed in transformants E1A + cHa-ras + bcl-2 after serum starvation. Taken together, these data suggest that Bcl-2 and Ras interaction might play a crucial role in the cell cycle checkpoints restoration and apoptotic events regulation in transformants E1A + cHa-ras + bcl-2 exposed to DNA-damaging factors or growth factor-deprived.
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PMID:[Anti-apoptotic and antiproliferative effect of bcl-2 gene transferred to E1A+cHa-ras-transformed cells]. 1469 53

E1A + c-Ha-ras-transformants overexpressing bcl-2 oncogene are able to be arrested at the G1/S boundary of the cell cycle after DNA damage and upon serum starvation, this cell cycle blockage being accompanied by a decrease in the activity of cyclin E--Cdk2 complexes. Roscovitine-induced inhibition of cyclin-dependent kinases (Cdks) activity does not result in the G1/S arrest of E1A + c-Ha-ras + bcl-2-transformants. Roscovitine treatment causes an accumulation of G2/M cells, mainly at the expense of mitotic cells. However, the expression of Bcl-2 oncoproducts does not re-establish the regulation of mitotic events broken by introduction of E1A and c-Ha-ras oncogenes in normal cells, as revealed by the treatment of E1A + c-Ha-ras + bcl-2-transformants with nocodazole inducing mitotic arrest in normal cells. In spite of the elevated expression of antiapoptotic bcl-2 gene in transformants, nocodazole treatment results in mass apoptotic death preceded by polyploidy. Roscovitine also induces apoptosis with no polyploid cell accumulation being observed. Inhibition of Cdks activity with Roscovitine, as well as violation of microtubule depolymerization with nocodazole result in the apoptotic death in the tested cell lines sensitive (E1A + c-Ha-ras) and resistant (E1A + c-Ha-ras + bcl-2) to damaging agents. Thus, the application of Roscovitine, a specific inhibitor of Cdks, suggests that the decrease in Cdks activity in E1A + c-Ha-ras + bcl-2-transformants is not likely to be responsible for G1/S cell cycle arrest realization after damaging influences. Moreover, an antiproliferative effect of Bcl-2 in E1A + c-Ha-ras-transformants is restricted by restoration of cell cycle events at G1/S and G2/M boundaries, and does not concern the program of mitotic events regulation.
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PMID:[Antiproliferative effect of bcl-2 gene does not concern the control of mitotic events]. 1521 71

Solid tumors are often placed under stress conditions, such as glucose starvation which may result in topoisomerase II drug resistance. In this study, we investigated whether glucose deprivation or substitution by fructose regulates tumor cell apoptosis induced by 2-acetyl furanonaphthoquinone (FNQ). We now show that FNQ exerts much greater antitumor activity than either 7-methoxy 2-ethyl FNQ or 2-ethyl FNQ. Whereas 0.8 microM FNQ induces apoptosis after 16 hours in glucose-supplemented conditions irrespective of bcl-2 overexpression in K1735 melanoma, 0.5 microM FNQ is also effective within 12 hours in low glucose or in fructose-supplemented medium. Under the latter conditions, apoptosis-associated PARP cleavage and cytosolic cytochrome C are increased, together with induction and partial translocation to mitochondria of phosphorylated Jun-N-terminal kinase and massive upregulation of mitochondrial Mn superoxide dismutase. We propose that mitochondrial colocalization of these activities is important in this synergistic anti-tumor effect of FNQ and glucose depletion. Since glucose limitation slows proliferation and decreases efficacy of some genotoxic drugs that trigger apoptosis in rapidly dividing cells, we propose evaluating FNQ as a novel therapeutic anti-cancer adjuvant against slowly proliferating tumors.
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PMID:Decreased glycolytic metabolism accelerates apoptosis in response to 2-acetyl furanonaphthoquinone in K1735 melanoma irrespective of bcl-2 overexpression. 1584 99

Introduction of bcl-2 gene in EIA + c-Ha-ras-transformed rat embryo fibroblasts, which are unable to be arrested after damaging influences and possess high proapoptotic sensitivity, results not only in suppression of cell death but also in re-establishment of cell cycle block following DNA damage and serum starvation. Flow cytometry showed that E1A + c-Ha-ras + bcl-2-transformants treated with DNA-intercalator adriamycin are capable of being arrested at G1/S boundary for a long time (for less than 5 days). According to the growth curve data, the number of Bcl-2-overexpressing cells remanins constant for a week of cultivation with adriamycin. Clonogenic efficacy of E1A + c-Ha-ras + bcl-2-cells is brought to no already in 16 h after adriamycin addition. Apoptotic death, revealed by oligonucleosomic fragmentation of DNA, as well as cell death, occurring due to mitotic catastrophe, after adriamycin treatment are almost absent in Bcl-2-overexpressing transformants, as compared with parental E1A + c-Ha-ras-transformants. Bcl-2 introduction in E1A + c-Ha-ras-transformants is accompanied by a rise of SA beta-Gal (Senescence Associated beta-Galactosidase) activity, which is commonly considered to be a marker of cell senescence. Adriamycin treatment of E1A + c-Ha-ras + bcl-2-transformants results in a much higher rise in SA beta-Gal activity, as compared with untreated cells. Co-immunoprecipitation experiments demonstrated the introduction of Bcl-2 to result in formation of Bcl-2 complexes with early region E1A oncoproducts, which are thought to be responsible for proapoptotic susceptibility of E1A-expressing transformants. The data obtained lead to suggestion that bcl-2 transfer to E1A + c-Ha-ras-transformants may induce a switch from the cell death program on the program of senescence after DNA damage, due, presumably, to Bcl-2 interaction with the apoptosis activator the viral oncoprotein E1A.
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PMID:[Antiapoptotic oncogene bcl-2 induces a program of senescence in E1A + c-Ha-ras-transformants treated with adriamycin]. 1671 90

The aim of the present study was to investigate whether fasting for 24 and 48 h induces apoptosis of rat mesenteric lymph node lymphocytes similar to that observed previously in diabetic patients and alloxan-induced diabetic rats. Several features of lymphocyte death were evaluated by flow cytometry. Plasma levels of glucose, NEFAs (non-esterified fatty acids) and ketone bodies (acetoacetate and beta-hydroxybutyrate) were determined in rats fasted for 24 and 48 h. Lymphocytes obtained from fasted rats had an increase in DNA fragmentation and phosphatidylserine externalization after 48 h of culture, although there was no loss of membrane integrity in lymphocytes even after 48 h of culture. Cytochrome c release from the mitochondrial intermembrane space into the cytosol was increased significantly in lymphocytes from fasted rats cultured for 24 h, whereas the levels of bcl-2 and bax proteins were not affected. Activities of caspases 3, 6, 8 and 9 were increased significantly in lymphocytes from rats fasted for 24 h, whereas only an increase in caspase 3 and 9 activities were observed in rats fasted for 48 h. In conclusion, fasting for 24 and 48 h caused a significant increase in the proportion of lymphocytes undergoing apoptosis. The occurrence of apoptosis was observed by DNA fragmentation, phosphatidylserine externalization, cytochrome c release from the mitochondria and activation of the caspase cascade. These findings support the hypothesis that conditions that raise plasma fatty acids levels (e.g. diabetes and starvation) may impair immune function by causing lymphocyte death.
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PMID:Induction of apoptosis in rat lymphocytes by starvation. 1693 13

E1A+ras-transformed rodent fibroblasts are unable to be arrested in the cell cycle and die by apoptosis in response to cytostatics, ionizing radiation (IR), or serum withdrawal. Overexpression of the human antiapoptotic gene bcl-2 suppresses apoptosis and induces reversible cell cycle arrest after IR or serum withdrawal and cell senescence after adriamycin treatment. Bcl-2-sustained adriamycin-induced cell senescence requires p38 MAPK, since the knockout of p38 MAPK abrogated anti-apoptotic and senescence-inducing effects of Bcl-2 in adriamycin-treated cells. Moreover, resistance to apoptosis and cell cycle arrest were not observed in p38-/- E1A+ras+bcl-2-transformants following IR or serum deprivation. However, the pro-apoptotic effect of nocodazole in E1A+ras-transformed cells can not be prevented by Bcl-2 overexpression independently of the presence of p38 MAPK. These results allow us to conclude that p38 is necessary for Bcl-2-induced inhibition of apoptosis, induction of cell cycle arrest and accelerated senescence after DNA damage and serum starvation, but not after nocodazole treatment.
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PMID:By blocking apoptosis, Bcl-2 in p38-dependent manner promotes cell cycle arrest and accelerated senescence after DNA damage and serum withdrawal. 1788 91


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