NOTCH PATHWAY AND INTELEUKIN-6 COOPERATE TO SUPPORT MULTIPLE MYELOMA CELL PROLIFERATION
(Abstract release date: 05/19/16)
EHA Library. Galletti S. 06/09/16; 132802; E1253
Mrs. Serena Galletti
Contributions
Contributions
Abstract
Abstract: E1253
Type: Eposter Presentation
Background
Multiple myeloma (MM) is a malignant plasma cells (PC) disorder characterized by PCs accumulation in the bone marrow (BM) and a close interaction between PCs and the surrounding microenvironment. Infact, BM stromal cells (BMSCs) sustain the survival and proliferation of tumor cells through adhesion molecules and the production of several cytokines, especially interleukin-6 (IL6). At the initial stage, MM cells strictly depend on IL6 produced by BMSCs and during disease progression may acquire independence and/or the ability to produce autonomously this cytokine.The Notch pathway is highly conserved and plays a crucial role in cell-fate decision, tissue patterning and morphogenesis. Recent evidences suggest a key role of Notch pathway in MM progression, by its ability to positive regulate cell proliferation, drug resistance and BM infiltration through the overexpression of both receptors (Notch1 and 2) and ligands (Jag1 and 2).
Aims
We investigated the cooperation between the Notch pathway and IL6 signaling in the promotion of MM cells proliferation. Particularly, we analyzed how Notch upregulation during MM progression may support tumor cells growth. Moreover, we evaluate if it could promote the activation of an IL6 autocrine loop in MM and favor IL6 paracrine production by the surrounding BMSCs.
Methods
Notch signaling modulation was induced in MM cell lines and primary MM cells as follows: upregulation by 5μg/mL soluble Jag1; down-regulation by 50μM DAPT or Jag1-2 RNA interference. qPCR was performed using SYBR Green. Absolute cells count and evaluation of IL6 protein expression was achieved by flow cytometry. Immunohistochemistry (IHC) for Hes6, IL6 and Ig light chain was performed on BM biopsies at different stages of MM.
Results
Gene expression profiling (GEP) analysis evidenced the upregulation of Jag1 and Hes5 (Notch transcriptional target) in MM and pPCL (primary plasma cell leukemia) cases compared to normal controls, and the overexpression of Notch2, Hes5 and Hes6 in the worst prognosis, MAF-traslocated MM patients. These data support the hypothesis that over-expression of Notch pathway members correlate with progression or high-risk MM.Notch activity was modulated in MM cell lines, allowing us to demonstrate that the dysregulation of Notch signal can substitute IL6 stimulation. Infact, Notch activation in IL6-dependent cells may stimulate their proliferation in the absence of the cytokine. On the opposite, upon Notch blockade, IL6-indipendent cells became dependent on IL6 for their growth. Notch pathway is also able to support MM cells proliferation through the promotion of an IL6 autonomous production. Indeed, IL6 expression in U266 cells depends upon Notch signaling and IHC study confirmed an association between Notch activation and IL6 immunoreactivity in MM cells.Since the most important source of IL6 are BMSCs, we focused our attention on the interaction between MM cells and the surrounding niche. We showed, by IHC staining, that MM cells induced IL6 expression in the nearby BMSCs. By co-culture systems, we demonstrated that MM cell-derived Jag ligands are able to activate Notch pathway in BMSCs, promoting IL6 secretion and MM cell proliferation, whereas Notch inhibition reverts this effect. Our results were further confirmed in ex-vivo co-cultures of MM cells and BMSCs, collected from patients.
Conclusion
Notch signaling in MM cells and in surrounding BMSCs promotes MM cell growth by boosting IL6 production. These results support the rationale for a Notch-directed approach in MM and suggest that Jag ligands may be promising molecular targets in MM therapy.
Session topic: E-poster
Keyword(s): IL-6, Microenvironment, Myeloma, Notch signaling
Type: Eposter Presentation
Background
Multiple myeloma (MM) is a malignant plasma cells (PC) disorder characterized by PCs accumulation in the bone marrow (BM) and a close interaction between PCs and the surrounding microenvironment. Infact, BM stromal cells (BMSCs) sustain the survival and proliferation of tumor cells through adhesion molecules and the production of several cytokines, especially interleukin-6 (IL6). At the initial stage, MM cells strictly depend on IL6 produced by BMSCs and during disease progression may acquire independence and/or the ability to produce autonomously this cytokine.The Notch pathway is highly conserved and plays a crucial role in cell-fate decision, tissue patterning and morphogenesis. Recent evidences suggest a key role of Notch pathway in MM progression, by its ability to positive regulate cell proliferation, drug resistance and BM infiltration through the overexpression of both receptors (Notch1 and 2) and ligands (Jag1 and 2).
Aims
We investigated the cooperation between the Notch pathway and IL6 signaling in the promotion of MM cells proliferation. Particularly, we analyzed how Notch upregulation during MM progression may support tumor cells growth. Moreover, we evaluate if it could promote the activation of an IL6 autocrine loop in MM and favor IL6 paracrine production by the surrounding BMSCs.
Methods
Notch signaling modulation was induced in MM cell lines and primary MM cells as follows: upregulation by 5μg/mL soluble Jag1; down-regulation by 50μM DAPT or Jag1-2 RNA interference. qPCR was performed using SYBR Green. Absolute cells count and evaluation of IL6 protein expression was achieved by flow cytometry. Immunohistochemistry (IHC) for Hes6, IL6 and Ig light chain was performed on BM biopsies at different stages of MM.
Results
Gene expression profiling (GEP) analysis evidenced the upregulation of Jag1 and Hes5 (Notch transcriptional target) in MM and pPCL (primary plasma cell leukemia) cases compared to normal controls, and the overexpression of Notch2, Hes5 and Hes6 in the worst prognosis, MAF-traslocated MM patients. These data support the hypothesis that over-expression of Notch pathway members correlate with progression or high-risk MM.Notch activity was modulated in MM cell lines, allowing us to demonstrate that the dysregulation of Notch signal can substitute IL6 stimulation. Infact, Notch activation in IL6-dependent cells may stimulate their proliferation in the absence of the cytokine. On the opposite, upon Notch blockade, IL6-indipendent cells became dependent on IL6 for their growth. Notch pathway is also able to support MM cells proliferation through the promotion of an IL6 autonomous production. Indeed, IL6 expression in U266 cells depends upon Notch signaling and IHC study confirmed an association between Notch activation and IL6 immunoreactivity in MM cells.Since the most important source of IL6 are BMSCs, we focused our attention on the interaction between MM cells and the surrounding niche. We showed, by IHC staining, that MM cells induced IL6 expression in the nearby BMSCs. By co-culture systems, we demonstrated that MM cell-derived Jag ligands are able to activate Notch pathway in BMSCs, promoting IL6 secretion and MM cell proliferation, whereas Notch inhibition reverts this effect. Our results were further confirmed in ex-vivo co-cultures of MM cells and BMSCs, collected from patients.
Conclusion
Notch signaling in MM cells and in surrounding BMSCs promotes MM cell growth by boosting IL6 production. These results support the rationale for a Notch-directed approach in MM and suggest that Jag ligands may be promising molecular targets in MM therapy.
Session topic: E-poster
Keyword(s): IL-6, Microenvironment, Myeloma, Notch signaling
Abstract: E1253
Type: Eposter Presentation
Background
Multiple myeloma (MM) is a malignant plasma cells (PC) disorder characterized by PCs accumulation in the bone marrow (BM) and a close interaction between PCs and the surrounding microenvironment. Infact, BM stromal cells (BMSCs) sustain the survival and proliferation of tumor cells through adhesion molecules and the production of several cytokines, especially interleukin-6 (IL6). At the initial stage, MM cells strictly depend on IL6 produced by BMSCs and during disease progression may acquire independence and/or the ability to produce autonomously this cytokine.The Notch pathway is highly conserved and plays a crucial role in cell-fate decision, tissue patterning and morphogenesis. Recent evidences suggest a key role of Notch pathway in MM progression, by its ability to positive regulate cell proliferation, drug resistance and BM infiltration through the overexpression of both receptors (Notch1 and 2) and ligands (Jag1 and 2).
Aims
We investigated the cooperation between the Notch pathway and IL6 signaling in the promotion of MM cells proliferation. Particularly, we analyzed how Notch upregulation during MM progression may support tumor cells growth. Moreover, we evaluate if it could promote the activation of an IL6 autocrine loop in MM and favor IL6 paracrine production by the surrounding BMSCs.
Methods
Notch signaling modulation was induced in MM cell lines and primary MM cells as follows: upregulation by 5μg/mL soluble Jag1; down-regulation by 50μM DAPT or Jag1-2 RNA interference. qPCR was performed using SYBR Green. Absolute cells count and evaluation of IL6 protein expression was achieved by flow cytometry. Immunohistochemistry (IHC) for Hes6, IL6 and Ig light chain was performed on BM biopsies at different stages of MM.
Results
Gene expression profiling (GEP) analysis evidenced the upregulation of Jag1 and Hes5 (Notch transcriptional target) in MM and pPCL (primary plasma cell leukemia) cases compared to normal controls, and the overexpression of Notch2, Hes5 and Hes6 in the worst prognosis, MAF-traslocated MM patients. These data support the hypothesis that over-expression of Notch pathway members correlate with progression or high-risk MM.Notch activity was modulated in MM cell lines, allowing us to demonstrate that the dysregulation of Notch signal can substitute IL6 stimulation. Infact, Notch activation in IL6-dependent cells may stimulate their proliferation in the absence of the cytokine. On the opposite, upon Notch blockade, IL6-indipendent cells became dependent on IL6 for their growth. Notch pathway is also able to support MM cells proliferation through the promotion of an IL6 autonomous production. Indeed, IL6 expression in U266 cells depends upon Notch signaling and IHC study confirmed an association between Notch activation and IL6 immunoreactivity in MM cells.Since the most important source of IL6 are BMSCs, we focused our attention on the interaction between MM cells and the surrounding niche. We showed, by IHC staining, that MM cells induced IL6 expression in the nearby BMSCs. By co-culture systems, we demonstrated that MM cell-derived Jag ligands are able to activate Notch pathway in BMSCs, promoting IL6 secretion and MM cell proliferation, whereas Notch inhibition reverts this effect. Our results were further confirmed in ex-vivo co-cultures of MM cells and BMSCs, collected from patients.
Conclusion
Notch signaling in MM cells and in surrounding BMSCs promotes MM cell growth by boosting IL6 production. These results support the rationale for a Notch-directed approach in MM and suggest that Jag ligands may be promising molecular targets in MM therapy.
Session topic: E-poster
Keyword(s): IL-6, Microenvironment, Myeloma, Notch signaling
Type: Eposter Presentation
Background
Multiple myeloma (MM) is a malignant plasma cells (PC) disorder characterized by PCs accumulation in the bone marrow (BM) and a close interaction between PCs and the surrounding microenvironment. Infact, BM stromal cells (BMSCs) sustain the survival and proliferation of tumor cells through adhesion molecules and the production of several cytokines, especially interleukin-6 (IL6). At the initial stage, MM cells strictly depend on IL6 produced by BMSCs and during disease progression may acquire independence and/or the ability to produce autonomously this cytokine.The Notch pathway is highly conserved and plays a crucial role in cell-fate decision, tissue patterning and morphogenesis. Recent evidences suggest a key role of Notch pathway in MM progression, by its ability to positive regulate cell proliferation, drug resistance and BM infiltration through the overexpression of both receptors (Notch1 and 2) and ligands (Jag1 and 2).
Aims
We investigated the cooperation between the Notch pathway and IL6 signaling in the promotion of MM cells proliferation. Particularly, we analyzed how Notch upregulation during MM progression may support tumor cells growth. Moreover, we evaluate if it could promote the activation of an IL6 autocrine loop in MM and favor IL6 paracrine production by the surrounding BMSCs.
Methods
Notch signaling modulation was induced in MM cell lines and primary MM cells as follows: upregulation by 5μg/mL soluble Jag1; down-regulation by 50μM DAPT or Jag1-2 RNA interference. qPCR was performed using SYBR Green. Absolute cells count and evaluation of IL6 protein expression was achieved by flow cytometry. Immunohistochemistry (IHC) for Hes6, IL6 and Ig light chain was performed on BM biopsies at different stages of MM.
Results
Gene expression profiling (GEP) analysis evidenced the upregulation of Jag1 and Hes5 (Notch transcriptional target) in MM and pPCL (primary plasma cell leukemia) cases compared to normal controls, and the overexpression of Notch2, Hes5 and Hes6 in the worst prognosis, MAF-traslocated MM patients. These data support the hypothesis that over-expression of Notch pathway members correlate with progression or high-risk MM.Notch activity was modulated in MM cell lines, allowing us to demonstrate that the dysregulation of Notch signal can substitute IL6 stimulation. Infact, Notch activation in IL6-dependent cells may stimulate their proliferation in the absence of the cytokine. On the opposite, upon Notch blockade, IL6-indipendent cells became dependent on IL6 for their growth. Notch pathway is also able to support MM cells proliferation through the promotion of an IL6 autonomous production. Indeed, IL6 expression in U266 cells depends upon Notch signaling and IHC study confirmed an association between Notch activation and IL6 immunoreactivity in MM cells.Since the most important source of IL6 are BMSCs, we focused our attention on the interaction between MM cells and the surrounding niche. We showed, by IHC staining, that MM cells induced IL6 expression in the nearby BMSCs. By co-culture systems, we demonstrated that MM cell-derived Jag ligands are able to activate Notch pathway in BMSCs, promoting IL6 secretion and MM cell proliferation, whereas Notch inhibition reverts this effect. Our results were further confirmed in ex-vivo co-cultures of MM cells and BMSCs, collected from patients.
Conclusion
Notch signaling in MM cells and in surrounding BMSCs promotes MM cell growth by boosting IL6 production. These results support the rationale for a Notch-directed approach in MM and suggest that Jag ligands may be promising molecular targets in MM therapy.
Session topic: E-poster
Keyword(s): IL-6, Microenvironment, Myeloma, Notch signaling
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