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Analysis of the anti-proliferative and the pro-apoptotic efficacy of Syk inhibition in multiple myeloma.

Koerber RM, Held SA, Heine A, Kotthoff P, Daecke SN, Bringmann A, Brossart P - Exp Hematol Oncol (2015)

Bottom Line: Incubation of MM cell lines as well as primary MM cells with Syk inhibitors resulted in a reduced proliferation and stromal cell-derived factor-1 alpha (SDF-1 alpha) induced migration that was accompanied by a concentration dependent inhibition of the MAP-Kinase, characterized by reduced phosphorylation of ERK an p38 molecules, and NF-kappaB signalling pathways.Furthermore, Syk inhibition induced apoptosis in MM cells in a dose-dependent manner, characterized by reduced expression of pro-caspase 3, increased PARP-1 cleavage and enhanced release of cytochrome c.In addition combined treatment of MM cells with Syk inhibitors and NVP-BEZ235 (dual PI3-kinase/mTOR inhibitor) or MAPK inhibitors (PD98059, SP600125, U0126, SB203580) resulted in increased apoptotic activity of the drugs.

View Article: PubMed Central - PubMed

Affiliation: Medical Clinic III, Department of Hematology and Oncology, University Hospital Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany.

ABSTRACT

Background: Multiple myeloma (MM) is a clonal B cell malignancy characterized by proliferation of malignant plasma cells in the bone marrow. Despite high-dose melphalan therapy with autologous stem cell transplantation (ASCT) and the introduction of immunomodulatory drugs like bortezomib or lenalidomide, that have been associated with improved survival, MM is still incurable and new treatment options are needed. In B cell malignancies such as chronic lymphocytic leukaemia (CLL) or diffuse large B cell lymphoma (DLBCL), Syk (spleen tyrosine kinase) inhibitors have shown promising in vitro and first clinical results. In our study, we analyzed the potential of Syk as a target in MM.

Methods: The MM cell lines AMO-1, U266 and RPMI8226 and primary MM cells were treated with the Syk inhibitors BAY61-3606, R406 or Piceatannol and proliferation, migration and apoptosis induction were analyzed. Effects on involved intracellular signaling cascades were determined by Western blotting. Furthermore, we analyzed synergistic and additive effects of Syk inhibitors in combination with established anti-myeloma drugs and experimental inhibitors (e.g. PI-3-Kinase inhibitor NVP-BEZ235).

Results: Incubation of MM cell lines as well as primary MM cells with Syk inhibitors resulted in a reduced proliferation and stromal cell-derived factor-1 alpha (SDF-1 alpha) induced migration that was accompanied by a concentration dependent inhibition of the MAP-Kinase, characterized by reduced phosphorylation of ERK an p38 molecules, and NF-kappaB signalling pathways. Furthermore, Syk inhibition induced apoptosis in MM cells in a dose-dependent manner, characterized by reduced expression of pro-caspase 3, increased PARP-1 cleavage and enhanced release of cytochrome c. In addition combined treatment of MM cells with Syk inhibitors and NVP-BEZ235 (dual PI3-kinase/mTOR inhibitor) or MAPK inhibitors (PD98059, SP600125, U0126, SB203580) resulted in increased apoptotic activity of the drugs.

Conclusions: Our results show that Syk inhibition might represent a promising new treatment option in MM with an increased efficacy when combined with MAP kinase inhibitors. Furthermore, our study strongly underlines the potency of Syk inhibitors as a potential therapeutic treatment option for MM patients.

No MeSH data available.


Related in: MedlinePlus

Efficiacy of Syk inhibition on cell viability is not reduced in the presence of Il-6. To determine the impact of IL-6 on the apoptotic effects of Syk inhibitors, MM cells were preincubated with IL-6 and nuclear fragmentation of MM cells treated with Syk inhibitors was measured by flow cytometry. In comparison with Bay61-3606 or Piceatannol alone, a combination with IL-6 did not reduce significantly the number of apoptotic cells. Results are expressed as the mean of three panels per pattern. Results are from one experiment representative of three. DMSO was used as control. The significance is related to DMSO. +P<1.000, *P < 0.1, **P < 0.01, ***P < 0.001.
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Fig6: Efficiacy of Syk inhibition on cell viability is not reduced in the presence of Il-6. To determine the impact of IL-6 on the apoptotic effects of Syk inhibitors, MM cells were preincubated with IL-6 and nuclear fragmentation of MM cells treated with Syk inhibitors was measured by flow cytometry. In comparison with Bay61-3606 or Piceatannol alone, a combination with IL-6 did not reduce significantly the number of apoptotic cells. Results are expressed as the mean of three panels per pattern. Results are from one experiment representative of three. DMSO was used as control. The significance is related to DMSO. +P<1.000, *P < 0.1, **P < 0.01, ***P < 0.001.

Mentions: IL-6 is a major growth and drug-resistance factor for MM cells that activates a cascade of signalling pathways mediating proliferation and anti-apoptotic effects. We therefore analyzed whether IL-6 might interfere with and abrogate the apoptotic effects induced by Syk inhibitors. Preincubation of MM cells with IL-6 had no effect on Piceatannol triggered apoptosis in MM cell lines (Fig. 6). Similarly, preincubation of MM cell lines with TLR ligands (TLR 2, 3, 4, 7/8) had no effect on the action of Syk inhibition (data not shown).Fig. 6


Analysis of the anti-proliferative and the pro-apoptotic efficacy of Syk inhibition in multiple myeloma.

Koerber RM, Held SA, Heine A, Kotthoff P, Daecke SN, Bringmann A, Brossart P - Exp Hematol Oncol (2015)

Efficiacy of Syk inhibition on cell viability is not reduced in the presence of Il-6. To determine the impact of IL-6 on the apoptotic effects of Syk inhibitors, MM cells were preincubated with IL-6 and nuclear fragmentation of MM cells treated with Syk inhibitors was measured by flow cytometry. In comparison with Bay61-3606 or Piceatannol alone, a combination with IL-6 did not reduce significantly the number of apoptotic cells. Results are expressed as the mean of three panels per pattern. Results are from one experiment representative of three. DMSO was used as control. The significance is related to DMSO. +P<1.000, *P < 0.1, **P < 0.01, ***P < 0.001.
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4526421&req=5

Fig6: Efficiacy of Syk inhibition on cell viability is not reduced in the presence of Il-6. To determine the impact of IL-6 on the apoptotic effects of Syk inhibitors, MM cells were preincubated with IL-6 and nuclear fragmentation of MM cells treated with Syk inhibitors was measured by flow cytometry. In comparison with Bay61-3606 or Piceatannol alone, a combination with IL-6 did not reduce significantly the number of apoptotic cells. Results are expressed as the mean of three panels per pattern. Results are from one experiment representative of three. DMSO was used as control. The significance is related to DMSO. +P<1.000, *P < 0.1, **P < 0.01, ***P < 0.001.
Mentions: IL-6 is a major growth and drug-resistance factor for MM cells that activates a cascade of signalling pathways mediating proliferation and anti-apoptotic effects. We therefore analyzed whether IL-6 might interfere with and abrogate the apoptotic effects induced by Syk inhibitors. Preincubation of MM cells with IL-6 had no effect on Piceatannol triggered apoptosis in MM cell lines (Fig. 6). Similarly, preincubation of MM cell lines with TLR ligands (TLR 2, 3, 4, 7/8) had no effect on the action of Syk inhibition (data not shown).Fig. 6

Bottom Line: Incubation of MM cell lines as well as primary MM cells with Syk inhibitors resulted in a reduced proliferation and stromal cell-derived factor-1 alpha (SDF-1 alpha) induced migration that was accompanied by a concentration dependent inhibition of the MAP-Kinase, characterized by reduced phosphorylation of ERK an p38 molecules, and NF-kappaB signalling pathways.Furthermore, Syk inhibition induced apoptosis in MM cells in a dose-dependent manner, characterized by reduced expression of pro-caspase 3, increased PARP-1 cleavage and enhanced release of cytochrome c.In addition combined treatment of MM cells with Syk inhibitors and NVP-BEZ235 (dual PI3-kinase/mTOR inhibitor) or MAPK inhibitors (PD98059, SP600125, U0126, SB203580) resulted in increased apoptotic activity of the drugs.

View Article: PubMed Central - PubMed

Affiliation: Medical Clinic III, Department of Hematology and Oncology, University Hospital Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany.

ABSTRACT

Background: Multiple myeloma (MM) is a clonal B cell malignancy characterized by proliferation of malignant plasma cells in the bone marrow. Despite high-dose melphalan therapy with autologous stem cell transplantation (ASCT) and the introduction of immunomodulatory drugs like bortezomib or lenalidomide, that have been associated with improved survival, MM is still incurable and new treatment options are needed. In B cell malignancies such as chronic lymphocytic leukaemia (CLL) or diffuse large B cell lymphoma (DLBCL), Syk (spleen tyrosine kinase) inhibitors have shown promising in vitro and first clinical results. In our study, we analyzed the potential of Syk as a target in MM.

Methods: The MM cell lines AMO-1, U266 and RPMI8226 and primary MM cells were treated with the Syk inhibitors BAY61-3606, R406 or Piceatannol and proliferation, migration and apoptosis induction were analyzed. Effects on involved intracellular signaling cascades were determined by Western blotting. Furthermore, we analyzed synergistic and additive effects of Syk inhibitors in combination with established anti-myeloma drugs and experimental inhibitors (e.g. PI-3-Kinase inhibitor NVP-BEZ235).

Results: Incubation of MM cell lines as well as primary MM cells with Syk inhibitors resulted in a reduced proliferation and stromal cell-derived factor-1 alpha (SDF-1 alpha) induced migration that was accompanied by a concentration dependent inhibition of the MAP-Kinase, characterized by reduced phosphorylation of ERK an p38 molecules, and NF-kappaB signalling pathways. Furthermore, Syk inhibition induced apoptosis in MM cells in a dose-dependent manner, characterized by reduced expression of pro-caspase 3, increased PARP-1 cleavage and enhanced release of cytochrome c. In addition combined treatment of MM cells with Syk inhibitors and NVP-BEZ235 (dual PI3-kinase/mTOR inhibitor) or MAPK inhibitors (PD98059, SP600125, U0126, SB203580) resulted in increased apoptotic activity of the drugs.

Conclusions: Our results show that Syk inhibition might represent a promising new treatment option in MM with an increased efficacy when combined with MAP kinase inhibitors. Furthermore, our study strongly underlines the potency of Syk inhibitors as a potential therapeutic treatment option for MM patients.

No MeSH data available.


Related in: MedlinePlus