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The inhibition of tyrosine kinase receptor signalling in leiomyosarcoma cells using the small molecule kinase inhibitor PTK787/ZK222584 (Vatalanib®).

Gaumann AK, Drexler HC, Lang SA, Stoeltzing O, Diermeier-Daucher S, Buchdunger E, Wood J, Bold G, Breier G - Int. J. Oncol. (2014)

Bottom Line: PTK787 turned out to inhibit cell migration even though no effects were observed upon stimulation with VEGF-A or PDGF-BB.However, VEGF-A, but not PDGF-BB-treated cells showed increased cell death upon PTK787 treatment.Upon receptor stimulation, PTK787 is able to inhibit subsequent phosphorylation events and influences cell survival but not metabolic activity and migration.

View Article: PubMed Central - PubMed

Affiliation: Institute of Pathology, Kaufbeuren‑Ravensburg, 87600 Kaufbeuren, Germany.

ABSTRACT
Leiomyosarcomas remain challenging tumors to manage and novel therapy strategies besides radiation and conventional chemotherapy are needed. Targeting angiogenesis by inhibition of vascular endothelial growth factor (VEGF) receptor tyrosine kinases (RTKs) of the tumor vasculature with small molecules is a promising new therapy. It has been shown recently that these receptors are not only expressed on tumor endothelium but also on tumor cells themselves. Thus, we investigated the expression of members of the VEGF receptor (VEGFR) family and corresponding growth factors in leiomyosarcoma tissue specimens and in the leiomyosarcoma cell lines SK-LMS-1 and SK-UT-1. We evaluated the influence of the VEGFR inhibitor PTK787/ZK222584 (PTK787) on cell growth, migration, apoptosis and phosphorylation of intracellular signalling molecules. In human leiomyosarcoma tissue specimens VEGFR‑1/-2 and platelet-derived growth factor receptor (PDGFR-β) were strongly expressed. Both leiomyosarcoma cell lines expressed VEGFR‑1/-3 and PDGFR-β but VEGFR-2 protein expression was positive only in SK-UT-1. SK-LMS-1 and SK-UT-1 cells secreted high and low amounts of VEGF-A, respectively, whereas PDGF-BB secretion was similar in both cell lines. Application of PTK787 led to partial inhibition of PDGF-BB-activated AKT/p90RSK and ERK1/2 signalling pathways. In contrast, protein phosphorylation was not affected by PTK787 in VEGF-A-treated cells. PTK787 turned out to inhibit cell migration even though no effects were observed upon stimulation with VEGF-A or PDGF-BB. In line, cell growth in leiomyosarcoma cell lines remained unchanged upon PTK787 treatment alone and with subsequent VEGF-A- or PDGF-BB-stimulation. However, VEGF-A, but not PDGF-BB-treated cells showed increased cell death upon PTK787 treatment. VEGFR family members are expressed in leiomyosarcomas in vivo and in vitro. Upon receptor stimulation, PTK787 is able to inhibit subsequent phosphorylation events and influences cell survival but not metabolic activity and migration. Thus, the inhibitor is possibly an additional option in the treatment of leiomyosarcomas.

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Related in: MedlinePlus

PTK787/ZK222584 (PTK787)-caused effects on signalling cascades (A) in vascular endothelial growth factor (VEGF)-A- and (B) platelet-derived growth factor (PDGF)-BB-treated cells. eIF4E was used as loading control. (A) Activation of signalling cascades is not affected by VEGF-A and/or PTK787 treatment. (B) PTK787 inhibited basal and PDGF-BB-caused ERK1/2, AKT/PKB- and p90RSK-phosphorylation. p, phospho.
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f3-ijo-45-06-2267: PTK787/ZK222584 (PTK787)-caused effects on signalling cascades (A) in vascular endothelial growth factor (VEGF)-A- and (B) platelet-derived growth factor (PDGF)-BB-treated cells. eIF4E was used as loading control. (A) Activation of signalling cascades is not affected by VEGF-A and/or PTK787 treatment. (B) PTK787 inhibited basal and PDGF-BB-caused ERK1/2, AKT/PKB- and p90RSK-phosphorylation. p, phospho.

Mentions: We investigated whether PTK787 could interfere with VEGF-A- or PDGF-BB-caused activation of intracellular signalling intermediates, which are known to be involved in VEGFR and PDGFR-signalling and regulate cell proliferation and migration. In Fig. 3 we show representative data gained with SK-UT-1. Results were similar for SK-LMS-1. Cells were incubated with either 0.1, 1 or 10 μM PTK787 or DMSO and subsequently stimulated with growth factors for different time intervals.


The inhibition of tyrosine kinase receptor signalling in leiomyosarcoma cells using the small molecule kinase inhibitor PTK787/ZK222584 (Vatalanib®).

Gaumann AK, Drexler HC, Lang SA, Stoeltzing O, Diermeier-Daucher S, Buchdunger E, Wood J, Bold G, Breier G - Int. J. Oncol. (2014)

PTK787/ZK222584 (PTK787)-caused effects on signalling cascades (A) in vascular endothelial growth factor (VEGF)-A- and (B) platelet-derived growth factor (PDGF)-BB-treated cells. eIF4E was used as loading control. (A) Activation of signalling cascades is not affected by VEGF-A and/or PTK787 treatment. (B) PTK787 inhibited basal and PDGF-BB-caused ERK1/2, AKT/PKB- and p90RSK-phosphorylation. p, phospho.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4215578&req=5

f3-ijo-45-06-2267: PTK787/ZK222584 (PTK787)-caused effects on signalling cascades (A) in vascular endothelial growth factor (VEGF)-A- and (B) platelet-derived growth factor (PDGF)-BB-treated cells. eIF4E was used as loading control. (A) Activation of signalling cascades is not affected by VEGF-A and/or PTK787 treatment. (B) PTK787 inhibited basal and PDGF-BB-caused ERK1/2, AKT/PKB- and p90RSK-phosphorylation. p, phospho.
Mentions: We investigated whether PTK787 could interfere with VEGF-A- or PDGF-BB-caused activation of intracellular signalling intermediates, which are known to be involved in VEGFR and PDGFR-signalling and regulate cell proliferation and migration. In Fig. 3 we show representative data gained with SK-UT-1. Results were similar for SK-LMS-1. Cells were incubated with either 0.1, 1 or 10 μM PTK787 or DMSO and subsequently stimulated with growth factors for different time intervals.

Bottom Line: PTK787 turned out to inhibit cell migration even though no effects were observed upon stimulation with VEGF-A or PDGF-BB.However, VEGF-A, but not PDGF-BB-treated cells showed increased cell death upon PTK787 treatment.Upon receptor stimulation, PTK787 is able to inhibit subsequent phosphorylation events and influences cell survival but not metabolic activity and migration.

View Article: PubMed Central - PubMed

Affiliation: Institute of Pathology, Kaufbeuren‑Ravensburg, 87600 Kaufbeuren, Germany.

ABSTRACT
Leiomyosarcomas remain challenging tumors to manage and novel therapy strategies besides radiation and conventional chemotherapy are needed. Targeting angiogenesis by inhibition of vascular endothelial growth factor (VEGF) receptor tyrosine kinases (RTKs) of the tumor vasculature with small molecules is a promising new therapy. It has been shown recently that these receptors are not only expressed on tumor endothelium but also on tumor cells themselves. Thus, we investigated the expression of members of the VEGF receptor (VEGFR) family and corresponding growth factors in leiomyosarcoma tissue specimens and in the leiomyosarcoma cell lines SK-LMS-1 and SK-UT-1. We evaluated the influence of the VEGFR inhibitor PTK787/ZK222584 (PTK787) on cell growth, migration, apoptosis and phosphorylation of intracellular signalling molecules. In human leiomyosarcoma tissue specimens VEGFR‑1/-2 and platelet-derived growth factor receptor (PDGFR-β) were strongly expressed. Both leiomyosarcoma cell lines expressed VEGFR‑1/-3 and PDGFR-β but VEGFR-2 protein expression was positive only in SK-UT-1. SK-LMS-1 and SK-UT-1 cells secreted high and low amounts of VEGF-A, respectively, whereas PDGF-BB secretion was similar in both cell lines. Application of PTK787 led to partial inhibition of PDGF-BB-activated AKT/p90RSK and ERK1/2 signalling pathways. In contrast, protein phosphorylation was not affected by PTK787 in VEGF-A-treated cells. PTK787 turned out to inhibit cell migration even though no effects were observed upon stimulation with VEGF-A or PDGF-BB. In line, cell growth in leiomyosarcoma cell lines remained unchanged upon PTK787 treatment alone and with subsequent VEGF-A- or PDGF-BB-stimulation. However, VEGF-A, but not PDGF-BB-treated cells showed increased cell death upon PTK787 treatment. VEGFR family members are expressed in leiomyosarcomas in vivo and in vitro. Upon receptor stimulation, PTK787 is able to inhibit subsequent phosphorylation events and influences cell survival but not metabolic activity and migration. Thus, the inhibitor is possibly an additional option in the treatment of leiomyosarcomas.

Show MeSH
Related in: MedlinePlus