Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0029463 (osteosarcoma)
 16,637 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A transient burst of poly(ADP-ribosyl)ation of nuclear proteins occurs early, prior to commitment to death, in human osteosarcoma cells undergoing apoptosis, followed by caspase-3-mediated cleavage of poly(ADP-ribose) polymerase (PARP). The generality of this early burst of poly(ADP-ribosyl)ation has now been investigated with human HL-60 cells, mouse 3T3-L1, and immortalized fibroblasts derived from wild-type mice. The effects of eliminating this early transient modification of nuclear proteins by depletion of PARP protein either by antisense RNA expression or by gene disruption on various morphological and biochemical markers of apoptosis were then examined. Marked caspase-3-like PARP cleavage activity, proteolytic processing of CPP32 to its active form, internucleosomal DNA fragmentation, and nuclear morphological changes associated with apoptosis were induced in control 3T3-L1 cells treated for 24 h with anti-Fas and cycloheximide but not in PARP-depleted 3T3-L1 antisense cells exposed to these inducers. Similar results were obtained with control and PARP-depleted human Jurkat T cells. Whereas immortalized PARP +/+ fibroblasts showed the early burst of poly(ADP-ribosyl)ation and a rapid apoptotic response when exposed to anti-Fas and cycloheximide, PARP -/- fibroblasts exhibited neither the early poly (ADP-ribosyl)ation nor any of the biochemical or morphological changes characteristic of apoptosis when similarly treated. Stable transfection of PARP -/- fibroblasts with wild-type PARP rendered the cells sensitive to Fas-mediated apoptosis. These results suggest that PARP and poly(ADP-ribosyl)ation may trigger key steps in the apoptotic program. Subsequent degradation of PARP by caspase-3-like proteases may prevent depletion of NAD and ATP or release certain nuclear proteins from poly(ADP-ribosyl)ation-induced inhibition, both of which might be required for late stages of apoptosis.
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PMID:Transient poly(ADP-ribosyl)ation of nuclear proteins and role of poly(ADP-ribose) polymerase in the early stages of apoptosis. 959 11

Spontaneous apoptosis in human osteosarcoma cells was observed to be associated with a marked increase in the intracellular abundance of p53. Immunoprecipitation and immunoblot analysis revealed that, together with a variety of other nuclear proteins, p53 undergoes extensive poly(ADP-ribosyl)ation early during the apoptotic program in these cells. Subsequent degradation of poly(ADP-ribose) (PAR), attached to p53 presumably by PAR glycohydrolase, the only reported enzyme to degrade PAR, was apparent concomitant with the onset of proteolytic processing and activation of caspase-3, caspase-3-mediated cleavage of poly(ADP-ribose) polymerase (PARP), and internucleosomal DNA fragmentation during the later stages of cell death. The decrease in PAR covalently bound to p53 also coincided with the marked induction of expression of the p53-responsive genes bax and Fas. These results suggest that poly(ADP-ribosyl)ation may play a role in the regulation of p53 function and implies a regulatory role for PARP and/or PAR early in apoptosis.
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PMID:Poly(ADP-ribosyl)ation of p53 during apoptosis in human osteosarcoma cells. 1023 7

An early transient burst of poly(ADP-ribosyl)ation of nuclear proteins was recently shown to be required for apoptosis to proceed in various cell lines (Simbulan-Rosenthal, C., Rosenthal, D., Iyer, S., Boulares, H., and Smulson, M. (1998) J. Biol. Chem. 273, 13703-13712) followed by cleavage of poly(ADP-ribose) polymerase (PARP), catalyzed by caspase-3. This inactivation of PARP has been proposed to prevent depletion of NAD (a PARP substrate) and ATP, which are thought to be required for later events in apoptosis. The role of PARP cleavage in apoptosis has now been investigated in human osteosarcoma cells and PARP -/- fibroblasts stably transfected with a vector encoding a caspase-3-resistant PARP mutant. Expression of this mutant PARP increased the rate of staurosporine and tumor necrosis factor-alpha-induced apoptosis, at least in part by reducing the time interval required for the onset of caspase-3 activation and internucleosomal DNA fragmentation, as well as the generation of 50-kilobase pair DNA breaks, thought to be associated with early chromatin unfolding. Overexpression of wild-type PARP in osteosarcoma cells also accelerated the apoptotic process, although not to the same extent as that apparent in cells expressing the mutant PARP. These effects of the mutant and wild-type enzymes might be due to the early and transient poly(ADP-ribose) synthesis in response to DNA breaks, and the accompanying depletion of NAD apparent in the transfected cells. The accelerated NAD depletion did not seem to interfere with the later stages of apoptosis. These results indicate that PARP activation and subsequent cleavage have active and complex roles in apoptosis.
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PMID:Role of poly(ADP-ribose) polymerase (PARP) cleavage in apoptosis. Caspase 3-resistant PARP mutant increases rates of apoptosis in transfected cells. 1043 58

This paper studies the cytotoxic effect induced by the topoisomerase I inhibitor camptothecin in human osteosarcoma Saos-2 cells, which lack p53 and contain a non-functional form of the product of the retinoblastoma gene, pRb. Cytotoxicity induced by camptothecin was dose- and time-dependent; the treatment with 100 nM camptothecin reduced cell viability by 50% at 32 h and by 75% at 72 h of exposure. The cytotoxic effect was caused by apoptosis, as ascertained by morphological evidence, acridine orange-ethidium bromide staining and flow cytometric analysis. Apoptosis was accompanied by both the activation of caspase-3 and the fragmentation of poly(ADP-ribose) polymerase. Treatment with camptothecin caused a threefold increase in the activity of c-Jun N-terminal kinase (JNK) and an eightfold increase in the level of phosphorylated c-Jun. The introduction of the RB gene into Saos-2 cells reduced the rate of cell growth. Moreover, stable clones of transfected cells were resistant to camptothecin. Exposure to 100 nM camptothecin for 72 h reduced the viability of transfected cells by only 10%; moreover, very modest effects were observed on the activity of JNK as well as on the level of phosphorylated c-Jun. The results reported in this paper support the conclusion that the expression of wild-type pRb in Saos-2 cells exerts an anti-apoptotic influence through the control of JNK activity.
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PMID:pRb suppresses camptothecin-induced apoptosis in human osteosarcoma Saos-2 cells by inhibiting c-Jun N-terminal kinase. 1141 38

Several endonucleases are implicated in the internucleosomal DNA fragmentation associated with apoptosis. The human Ca2+- and Mg2+-dependent endonuclease DNAS1L3 is inhibited by poly(ADP-ribosyl)ation in vitro, and its activation during apoptosis shows a time course similar to that of the cleavage of poly(ADP-ribose) polymerase-1 (PARP-1). The role of the cleavage and consequent inactivation of PARP-1 by caspase-3 in the activation of DNAS1L3 has now been investigated further both in vitro and in vivo. In an in vitro system based on purified recombinant proteins and NAD, caspase-3 prevented the inhibition of DNAS1L3 endonuclease activity by wild-type PARP-1 but not that induced by a caspase-3-resistant PARP-1 mutant. The induction by etoposide of apoptosis in human osteosarcoma cells (which were shown not to express endogenous DNAS1L3) was accompanied by internucleosomal DNA fragmentation only after transfection of the cells with a plasmid encoding DNAS1L3. This DNA fragmentation in etoposide-treated cells was blocked by 1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid, an inhibitor of intracellular Ca2+ release. Expression of the endonuclease subunit of DNA fragmentation factor (DFF40) and cleavage of its inhibitor, DFF45, were not sufficient to cause internucleosomal DNA fragmentation in osteosarcoma cells during etoposide-induced apoptosis. Coexpression of caspase-3-resistant PARP-1 mutant with DNAS1L3 in osteosarcoma cells blocked etoposide-induced internucleosomal DNA fragmentation and resulted in persistent poly(ADP-ribosyl)ation of DNAS1L3; it did not, however, prevent the activation of caspase-3 and the consequent cleavage of endogenous PARP-1. These results indicate that PARP-1 cleavage during apoptosis is not simply required to prevent excessive depletion of NAD and ATP but is also necessary to release DNAS1L3 from poly(ADP-ribosyl)ation-mediated inhibition.
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PMID:Regulation of DNAS1L3 endonuclease activity by poly(ADP-ribosyl)ation during etoposide-induced apoptosis. Role of poly(ADP-ribose) polymerase-1 cleavage in endonuclease activation. 1169 7

The cytotoxic effect of the chemotherapeutic drug etoposide (VP-16) is thought to result from its ability to induce DNA damage and thereby to trigger apoptosis. Internucleosomal DNA fragmentation occurs late during apoptosis in many cell types. However, whereas human osteosarcoma cells undergo internucleosomal DNA fragmentation during staurosporine-induced apoptosis, they fail to do so in response to VP-16. Recently, we showed that these cells also do not express the poly(ADP-ribosyl)ation-regulated Ca(2+)- and Mg(2+)-dependent endonuclease DNAS1L3. The possibility that this deficiency underlies the failure of these cells to undergo internucleosomal DNA fragmentation in response to VP-16 was investigated. The proteolytic processing and consequent activation of procaspase-3, cleavage of the inhibitory subunit of DNA fragmentation factor, and the degradation of DNA into 50-kb fragments occurred similarly in osteosarcoma cells exposed to either staurosporine or VP-16. However, the additional processing of the 50-kb DNA fragments to oligonucleosomal fragments was not apparent in the VP-16-treated cells. Ectopic expression of DNAS1L3 conferred on osteosarcoma cells the ability to undergo VP-16-induced internucleosomal DNA fragmentation. Furthermore, expression of DNAS1L3 markedly potentiated the cytotoxic effect of VP-16 in these cells. Both DNAS1L3-mediated and staurosporine-induced internucleosomal DNA fragmentation were Ca(2+) dependent, but only the DNAS1L3-mediated DNA cleavage was blocked by expression of a caspase-3-resistant mutant of poly(ADP-ribose) polymerase-1. The present work results suggest a direct relation between the activity of a chemotherapeutic drug (VP-16) and a specific endonuclease (DNAS1L3). They also indicate that internucleosomal DNA fragmentation plays an active role in apoptosis and that the failure of cancer cells to undergo such DNA degradation may contribute to the development of resistance to chemotherapeutic drugs.
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PMID:The Poly(ADP-ribose) polymerase-1-regulated endonuclease DNAS1L3 is required for etoposide-induced internucleosomal DNA fragmentation and increases etoposide cytotoxicity in transfected osteosarcoma cells. 1215 52

This study demonstrates that in human osteosarcoma cells treatment with 3-aminobenzamide (3-AB), a potent inhibitor of poly(ADP-ribose) polymerase (PARP), induces morphological and biochemical features of differentiation, the duration of which depends on whether or not the normal RB gene is expressed. In Saos-2 cells expressing a non-functional Rb protein, 3-AB treatment induced the formation of transient, short dendritic-like protrusions. In RB-transfected-Saos-2 cells (a clone previously generated in our laboratory that shows stable expression of wild-type Rb protein), 3-AB induced marked and prolonged changes with the formation of long dendritic-like protrusions and the appearance of stellate (osteocyte-like) cells. In MG-63 cells producing a wild-type Rb protein, 3-AB treatment had more marked effects, with a larger number of cells assuming the stellate appearance of osteocytes, which were connected to each other via junctions resembling small channels. Regardless of cell type, at some point after 3-AB treatment the differentiative attempt failed and the cells died. Death was apoptotic, as demonstrated by chromatin condensation and fragmentation, specific cleavage of PARP and Lamin-B, processing of caspase-3 and the appearance of Bax immunoreactive species. Enzymatic assay and RT-PCR of alkaline phosphatase (ALP) - an enzyme whose levels markedly decrease when osteoblasts undergo terminal differentiation into osteocytes - showed that 3-AB treatment markedly lowered ALP expression. Simultaneously, 3-AB treatment markedly increased the expression of CD44, a transmembrane multifunctional adhesion molecule and sensitive marker of osteocytic differentiation. This study hypothesizes a cross-talk between pRb and PARP and suggests that PARP may be a useful target for anticancer drugs.
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PMID:The effect of 3-aminobenzamide, inhibitor of poly(ADP-ribose) polymerase, on human osteosarcoma cells. 1461 22

The chemopreventive activity of resveratrol (RSVL) has been demonstrated in several types of cancer. However, its effects and the underling mechanisms remain poorly understood. In this study, we investigated the involvement of the mitogen activated protein kinase (MAPK)/p53 signal transduction mechanism in RSVL-induced growth inhibition using a human osteosarcoma cell line. We demonstrate that RSVL reduces cell viability and growth of SJSA1 osteosarcoma cells. Morphological profiles and 4,6-diamidino-2-phenylindole nuclear staining of RSVL-treated cells indicated marked nuclear fragmentation. Cleavage of the (116-kDa) poly(ADP-ribose) polymerase protein into an 89-kDa fragment (a proapoptotic marker system) was substantially augmented by RSVL treatment. RSVL-dependent growth impairment was preceded by enhanced phosphorylation of extracellular signal-regulated kinase (ERK)1/2 (at Thr202/Tyr204). Likewise, RSVL increased the phosphorylation of p53 tumor suppressor protein (at Ser15). The effects of RSVL on ERKs and on p53 phosphorylation were abrogated by either the MAPK inhibitor PD98059 or the p53 inhibitor pifithrine-alpha. The present study indicates that RSVL antiproliferative effects on osteosarcoma cells are mediated by the activation of the ERKs/p53 signaling pathway and therefore identifies new targets for strategies to treat and/or prevent osteosarcoma.
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PMID:Potent antiproliferative effects of resveratrol on human osteosarcoma SJSA1 cells: Novel cellular mechanisms involving the ERKs/p53 cascade. 1681 13

Previous studies have shown that oridonin, a diterpenoid isolated from Rabdosia rubescens, was able to inhibit proliferation and induce apoptosis in several cell types. But the mechanisms remain poorly understood. In this study, we investigated the apoptosis-inducing effect and mechanisms of action of oridonin in human osteosarcoma cells. Our results demonstrated that oridonin induced concentration- and time-dependent suppression of proliferation and activation of apoptosis in U2OS, MG63 and SaOS-2 osteosarcoma cell lines. Oridonin induced the release of cytochrome c accompanied by activation of caspase-9, caspase-3 and cleavage of poly(ADP-ribose) polymerase (PARP). These events were all inhibited by z-VAD-fmk, a universal inhibitor of caspases. Oridonin treatment dephosphorylated constitutively active AKT, FOXO transcription factor, and glycogen synthase kinase 3 (GSK3). In addition, oridonin decreased the phosphorylation of ERK and increased the phosphorylation of p38 MAPK and JNK. Furthermore, oridonin treatment down-regulated the expression of the inhibitor of apoptosis protein(IAP) in osteosarcoma cells. All together, our results suggested that oridonin is able to inactivate Akt and ERK and activate p38 MAPK and JNK signalling pathways in osteosarcoma cells causing the suppression of proliferation and induction of mitochondria- and caspase-dependent apoptosis.
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PMID:Oridonin induced apoptosis through Akt and MAPKs signaling pathways in human osteosarcoma cells. 1721 75

The affinity of the poly(ADP-ribose) polymerase-1 (PARP-1) for platinum-damaged DNA was first discovered during photo-cross-linking experiments using the photoactive compound Pt-BP6 [J. Am. Chem. Soc.2004, 126, 6536-6537], an analogue of the anticancer drug cis-diamminedichloroplatinum(II), cisplatin. Although PARP inhibitors sensitize cancer cells to cisplatin, there are conflicting reports in the literature about their efficacy. In order to improve our understanding of the mechanism by which PARP inhibition might potentiate the cell-killing ability of cisplatin, and to shed light on the source of the discrepancy among different laboratories, we have in the present study probed the influence of three PARP inhibitors in four types of cancer cells, cervical (HeLa), testicular (NTera2), pancreatic (BxPC3), and osteosarcoma (U2OS), on the results of Pt-BP6 photo-cross-linking experiments and cytotoxicity assays. We find that the activity of PARP proteins following exposure to platinum-modified DNA results in the dissociation of DNA-bound proteins. PARP inhibitors were able to sensitize some, but not all, of the cell lines to cisplatin. This cell line-dependence and the potential consequences of PARP-initiated protein removal from platinum-DNA lesions are discussed. Control experiments revealed that NTera2 cells are especially sensitive to PARP inhibition.
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PMID:Poly(ADP-ribose) polymerase-1 activity facilitates the dissociation of nuclear proteins from platinum-modified DNA. 1897 44


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