Downregulation of uPA inhibits migration and PI3k/Akt signaling in glioblastoma cells

Chandrasekar, Nirmala; Mohanam, Sanjeeva; Gujrati, Meena; Olivero, William C.; Dinh, Dzung H.; Rao, Jasti S.

doi:10.1038/sj.onc.1206164

Cited by 99 publications

(84 citation statements)

References 46 publications

(43 reference statements)

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“…These Rho-like G-proteins are known principally for their pivotal role in regulating the actin cytoskeleton in cell migration (Burridge and Wennerberg, 2004). PI3K has been thought to be a key molecule in the activation of cell migration through Rac signaling (Chandrasekar et al, 2003;van Leeuwen et al, 2003 Kawauchi et al, 2003) and p38MAPK (Rousseau et al, 1997;Cara et al, 2001;Ishizuka et al, 2001;Kimura et al, 2003;Pichon et al, 2004), have also been reported to be involved in cell migration. Consistent with these reports, our results indicate that activation of PI3K is required for the induction of glioma cell migration as well as for the activation of p38MAPK and JNK in response to LPA.…”

Section: Discussionmentioning

confidence: 99%

Role of p38 mitogen-activated kinase and c-Jun terminal kinase in migration response to lysophosphatidic acid and sphingosine-1-phosphate in glioma cells

et al. 2005

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A potential role for 1-oleoyl-sn-glycero-3-phosphate or lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P) in the regulation of malignant diseases has been widely considered. In this study, we found that in transformed astroglial cells, the expression profile of lysophospholipid receptor mRNA and the action modes of LPA and S1P on cell motility were changed: there was a change in the acquisition of the ability of LPA to stimulate cell migration and a change in the migratory response to S1P from stimulation through S1P 1 to inhibition through S1P 2 . LPA-induced cell migration was almost completely inhibited by either pertussis toxin, LPA 1 receptor antagonists including Ki16425 (3-(4-[4-([1-(2-chlorophenyl)ethoxy]carbonyl amino)-3-methyl-5-isoxazolyl] benzylsulfonyl)propanoic acid) or an inhibitor of phosphatidylinositol 3-kinase (PI3K) wortmannin. The LPA-induced action was also suppressed, although incompletely, by several specific inhibitors for intracellular signaling pathways including Rac1, Cdc42, p38 mitogen-activated protein kinase (p38MAPK) and c-Jun terminal kinase (JNK), but not extracellular signalregulated kinase. Nearly complete inhibition of migration response to LPA, however, required simultaneous inhibition of both the p38MAPK and JNK pathways. Inhibition of Rac1 suppressed JNK but not p38MAPK, while the activity of p38MAPK was abolished by a dominantnegative form of Cdc42. These findings suggest that, in glioma cells, the PI3K/Cdc42/p38MAPK and PI3K/ Rac1/JNK pathways are equally important for LPA 1 receptor-mediated migration.

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Section: Discussionmentioning

confidence: 99%

Role of p38 mitogen-activated kinase and c-Jun terminal kinase in migration response to lysophosphatidic acid and sphingosine-1-phosphate in glioma cells

et al. 2005

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“…Urokinase itself has been reported to stimulate PI3K activity and activates the downstream effectors Akt [15,16] and Rac1 [17]. Inversely, antisense uPA in glioblastoma cells causes a decrease both in wound migration and in PI3K/Akt activity [18]. Conversely, looking at PAI-1 levels, both hypoxia-induced PAI-1 expression [19] and nerve growth factor-induced PAI-1 expression [20] can be inhibited by PI3K inhibitors.…”

Section: Introductionmentioning

confidence: 99%

Phosphatidylinositol 3-kinase/Akt regulates the balance between plasminogen activator inhibitor-1 and urokinase to promote migration of SKOV-3 ovarian cancer cells

Whitley

Beaulieu

Carter

et al. 2007

Gynecologic Oncology

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Objectives-Increased levels of urokinase-type plasminogen activator (uPA) are associated with shortened overall survival in ovarian cancer patients. Additionally, elevated levels of the serine protease inhibitor (serpin), plasminogen activator inhibitor-1 (PAI-1), a uPA inhibitor, have also been correlated with an unfavorable prognosis in ovarian cancer. Therefore, it is critical to understand the signaling pathways that regulate PAI-1 and uPA expression in cancer cell migration-invasion.Methods-We studied the PI3K/Akt, Rho kinase/ROCK, p38 MAPK and MEK pathways and their modulation of PAI-1 and uPA expression and wound-induced cell migration in SKOV-3 ovarian cancer cells. The PI3K/Akt pathway was further examined using pharmacological inhibitors (LY294002 and wortmannin), Akt siRNA, constitutively active Akt adenovirus and treatment with IGF-1/insulin in the SKOV-3 cells.Results-The PI3K/Akt pathway negatively regulates PAI-1 expression and positively correlates with migratory abilities and uPA expression in SKOV-3 cells. A reduction in active Akt results in an increase in PAI-1 expression coupled with a decrease in uPA expression to ultimately result in reduced cell migration and invasion. By contrast, an increase in Akt activity reduces PAI-1 expression and results in an increase in SKOV-3 wound-induced cell migration. Furthermore, IGF-1 and insulin stimulated SKOV-3 migration by altering the balance between uPA and PAI-1 to favor uPA, and the enhanced migration was attenuated by treatment with LY294002 indicating PI3K/Akt in this pathway. Conclusions-These results suggest an overall ovarian tumor-protective role for PAI-1, and that the PI3K/Akt signaling pathway regulates the ratio of PAI-1:uPA to either increase or decrease cell migration.

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“…Selected cells were lysed in RIPA buffer (50 mM Tris at pH 8, 150 mM NaCl, 1% NP40, 0.5% deoxycholate, 0.1% SDS). 20, 40 or 80 micrograms of Proteins (20,40 or 80 µg) were separated by 8-12% SDS-PAGE and transferred to polyvinylidine difluoride membranes (Millipore, Billerica, MA). Western blots were probed with the indicated antibodies.…”

Section: P53mentioning

confidence: 99%

“…Therefore, mitogenic signalling through PI(3)K-PKB-GSK3β influences cyclin D1 stability and its nuclear activity, leading to cell-cycle progression 2 . uPA induces growth factor-related PI(3)K-PKB signalling 20 and, as a result, uPA activity may result in nuclear retention of cyclin D1 by inducing loss of GSK3β activity through phosphorylation on Ser 9. When cyclin D1 localization was determined in ageing MEFs, a striking but gradual nuclear exclusion of cyclin D1 was observed (Fig.…”

mentioning

confidence: 99%

Plasminogen activator inhibitor-1 is a critical downstream target of p53 in the induction of replicative senescence

2006

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p53 limits the proliferation of primary diploid fibroblasts by inducing a state of growth arrest named replicative senescence -a process which protects against oncogenic transformation and requires integrity of the p53 tumour suppressor pathway [1][2][3] . However, little is known about the downstream target genes of p53 in this growth-limiting response. Here, we report that suppression of the p53 target gene encoding plasminogen activator inhibitor-1 (PAI-1) by RNA interference (RNAi) leads to escape from replicative senescence both in primary mouse embryo fibroblasts and primary human BJ fibroblasts. PAI-1 knockdown results in sustained activation of the PI(3)K-PKB-GSK3β pathway and nuclear retention of cyclin D1, consistent with a role for PAI-1 in regulating growth factor signalling. In agreement with this, we find that the PI(3)K-PKB-GSK3β-cyclin D1 pathway is also causally involved in cellular senescence. Conversely, ectopic expression of PAI-1 in proliferating p53-deficient murine or human fibroblasts induces a phenotype displaying all the hallmarks of replicative senescence. Our data indicate that PAI-1 is not merely a marker of senescence, but is both necessary and sufficient for the induction of replicative senescence downstream of p53.Primary murine fibroblasts activate the p19 ARF -p53 tumour suppressor pathway during prolonged culturing in vitro, which induces a postmitotic state referred to as replicative senescence. Senescence can be overcome by loss of either p19 ARF , p53 or the combined loss of all three retinoblastoma family proteins 1,2 . Proliferation of fibroblasts is induced by growth factors which activate cyclin-dependent kinases (CDKs), and in turn inactivate pRb's growth-limiting ability 2 , a G1 cell-cycle checkpoint that is often deregulated in cancer 3 . It is unclear which of the many downstream p53-target genes is responsible for the p53-dependent induction of replicative senescence. An attractive candidate is the CDK inhibitor p21 CIP1. However, mouse embryo fibroblasts (MEFs) knocked out for p21 CIP1 are not immortal 4 . Here, we identify an unexpected causal role for the urokinase type plasminogen activator (uPA)-PAI-1 system in the induction of replicative senescence. The serpin and extra-cellular matrix (ECM)-associated protein PAI-1 is a direct target of p53 (ref. 5, 6), is upregulated in ageing fibroblasts in vivo and in vitro, and is considered a marker of replicative senescence 7-9 . PAI-1 inhibits the activity of the secreted protease uPA by forming a stable complex. uPA expression can cause cells to progress through G1 into S phase 10 , most likely through activating a mitogenic signalling cascade by increasing the bioavailability of growth factors.To investigate the role of PAI-1 in replicative senescence, two independent retroviral vectors were generated that targeted murine PAI-1 for suppression through RNAi (Fig. 1a). As inhibition of PAI-1 expression leads to activation of uPA 12,13 , we asked whether overexpression of uPA also caused immortalisation. Retrovirusme...

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Downregulation of uPA inhibits migration and PI3k/Akt signaling in glioblastoma cells

Cited by 99 publications

References 46 publications

Role of p38 mitogen-activated kinase and c-Jun terminal kinase in migration response to lysophosphatidic acid and sphingosine-1-phosphate in glioma cells

Role of p38 mitogen-activated kinase and c-Jun terminal kinase in migration response to lysophosphatidic acid and sphingosine-1-phosphate in glioma cells

Phosphatidylinositol 3-kinase/Akt regulates the balance between plasminogen activator inhibitor-1 and urokinase to promote migration of SKOV-3 ovarian cancer cells

Plasminogen activator inhibitor-1 is a critical downstream target of p53 in the induction of replicative senescence

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