Limits...
TRAIL-R2 promotes skeletal metastasis in a breast cancer xenograft mouse model.

Fritsche H, Heilmann T, Tower RJ, Hauser C, von Au A, El-Sheikh D, Campbell GM, Alp G, Schewe D, Hübner S, Tiwari S, Kownatzki D, Boretius S, Adam D, Jonat W, Becker T, Glüer CC, Zöller M, Kalthoff H, Schem C, Trauzold A - Oncotarget (2015)

Bottom Line: Strikingly, in addition to the reduced levels of the proliferation-promoting factor HMGA2 and corresponding inhibition of cell proliferation, knockdown of TRAIL-R2 increased the levels of E-Cadherin and decreased migration.In accordance, cell migration towards SDF-1 was significantly impaired by TRAIL-R2 knockdown.Conversely, overexpression of TRAIL-R2 upregulated CXCR4 levels and enhanced SDF-1-directed migration.

View Article: PubMed Central - PubMed

Affiliation: Division of Molecular Oncology, Institute for Experimental Cancer Research, CCC-North, University of Kiel, Kiel, Germany.

ABSTRACT
Despite improvements in detection, surgical approaches and systemic therapies, breast cancer remains typically incurable once distant metastases occur. High expression of TRAIL-R2 was found to be associated with poor prognostic parameters in breast cancer patients, suggesting an oncogenic function of this receptor. In the present study, we aimed to determine the impact of TRAIL-R2 on breast cancer metastasis. Using an osteotropic variant of MDA-MB-231 breast cancer cells, we examine the effects of TRAIL-R2 knockdown in vitro and in vivo. Strikingly, in addition to the reduced levels of the proliferation-promoting factor HMGA2 and corresponding inhibition of cell proliferation, knockdown of TRAIL-R2 increased the levels of E-Cadherin and decreased migration. In vivo, these cells were strongly impaired in their ability to form bone metastases after intracardiac injection. Evaluating possible underlying mechanisms revealed a strong downregulation of CXCR4, the receptor for the chemokine SDF-1 important for homing of cancers cells to the bone. In accordance, cell migration towards SDF-1 was significantly impaired by TRAIL-R2 knockdown. Conversely, overexpression of TRAIL-R2 upregulated CXCR4 levels and enhanced SDF-1-directed migration. We therefore postulate that inhibition of TRAIL-R2 expression could represent a promising therapeutic strategy leading to an effective impairment of breast cancer cell capability to form skeletal metastases.

No MeSH data available.


Related in: MedlinePlus

Knockdown of TRAIL-R2 in MDA-MB-231-BO cells downregulates the expression of CXCR4 and inhibits migration towards SDF-1Control (Ctrl-shRNA) and TRAIL-R2 knockdown cells (R2-shRNA-1 or R2-shRNA-2) were analyzed in regard to their migration capacity towards SDF-1 in a trans-well assay (A). Expression of TRAIL-R1, TRAIL-R2, CXCR4 and EGFR was assessed by flow cytometry on non-permeabilized and permeabilized cells (B) and percent of stained cells (C), as well as staining intensities per cell (D), relative to non-specific antibody controls, were quantified. Graphs represent average values ± SD. (A: n = 4, B-D: n = 3) (*p < 0.05, **p < 0.01 ***p < 0.001).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4496234&req=5

Figure 6: Knockdown of TRAIL-R2 in MDA-MB-231-BO cells downregulates the expression of CXCR4 and inhibits migration towards SDF-1Control (Ctrl-shRNA) and TRAIL-R2 knockdown cells (R2-shRNA-1 or R2-shRNA-2) were analyzed in regard to their migration capacity towards SDF-1 in a trans-well assay (A). Expression of TRAIL-R1, TRAIL-R2, CXCR4 and EGFR was assessed by flow cytometry on non-permeabilized and permeabilized cells (B) and percent of stained cells (C), as well as staining intensities per cell (D), relative to non-specific antibody controls, were quantified. Graphs represent average values ± SD. (A: n = 4, B-D: n = 3) (*p < 0.05, **p < 0.01 ***p < 0.001).

Mentions: We found that inhibition of TRAIL-R2 expression in osteotropic breast cancer cells dramatically reduced their capability to form skeletal metastases after intracardiac injection. However, once established, the metastatic growth, as well as the osteolytic activity, was independent of the TRAIL-R2 expression status. This strongly suggests a role for TRAIL-R2 in the regulation of the bone homing capacity of these cells. To test this hypothesis, cells were analyzed for their ability to migrate towards SDF-1, a major bone marrow-secreted chemoattractant for metastatic cancer cells [34]. Using an in vitro migration assay in the modified Boyden Chamber, we found that knockdown of TRAIL-R2 indeed significantly decreased the migration capacity of the cells towards SDF-1 (Figure 6A).


TRAIL-R2 promotes skeletal metastasis in a breast cancer xenograft mouse model.

Fritsche H, Heilmann T, Tower RJ, Hauser C, von Au A, El-Sheikh D, Campbell GM, Alp G, Schewe D, Hübner S, Tiwari S, Kownatzki D, Boretius S, Adam D, Jonat W, Becker T, Glüer CC, Zöller M, Kalthoff H, Schem C, Trauzold A - Oncotarget (2015)

Knockdown of TRAIL-R2 in MDA-MB-231-BO cells downregulates the expression of CXCR4 and inhibits migration towards SDF-1Control (Ctrl-shRNA) and TRAIL-R2 knockdown cells (R2-shRNA-1 or R2-shRNA-2) were analyzed in regard to their migration capacity towards SDF-1 in a trans-well assay (A). Expression of TRAIL-R1, TRAIL-R2, CXCR4 and EGFR was assessed by flow cytometry on non-permeabilized and permeabilized cells (B) and percent of stained cells (C), as well as staining intensities per cell (D), relative to non-specific antibody controls, were quantified. Graphs represent average values ± SD. (A: n = 4, B-D: n = 3) (*p < 0.05, **p < 0.01 ***p < 0.001).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4496234&req=5

Figure 6: Knockdown of TRAIL-R2 in MDA-MB-231-BO cells downregulates the expression of CXCR4 and inhibits migration towards SDF-1Control (Ctrl-shRNA) and TRAIL-R2 knockdown cells (R2-shRNA-1 or R2-shRNA-2) were analyzed in regard to their migration capacity towards SDF-1 in a trans-well assay (A). Expression of TRAIL-R1, TRAIL-R2, CXCR4 and EGFR was assessed by flow cytometry on non-permeabilized and permeabilized cells (B) and percent of stained cells (C), as well as staining intensities per cell (D), relative to non-specific antibody controls, were quantified. Graphs represent average values ± SD. (A: n = 4, B-D: n = 3) (*p < 0.05, **p < 0.01 ***p < 0.001).
Mentions: We found that inhibition of TRAIL-R2 expression in osteotropic breast cancer cells dramatically reduced their capability to form skeletal metastases after intracardiac injection. However, once established, the metastatic growth, as well as the osteolytic activity, was independent of the TRAIL-R2 expression status. This strongly suggests a role for TRAIL-R2 in the regulation of the bone homing capacity of these cells. To test this hypothesis, cells were analyzed for their ability to migrate towards SDF-1, a major bone marrow-secreted chemoattractant for metastatic cancer cells [34]. Using an in vitro migration assay in the modified Boyden Chamber, we found that knockdown of TRAIL-R2 indeed significantly decreased the migration capacity of the cells towards SDF-1 (Figure 6A).

Bottom Line: Strikingly, in addition to the reduced levels of the proliferation-promoting factor HMGA2 and corresponding inhibition of cell proliferation, knockdown of TRAIL-R2 increased the levels of E-Cadherin and decreased migration.In accordance, cell migration towards SDF-1 was significantly impaired by TRAIL-R2 knockdown.Conversely, overexpression of TRAIL-R2 upregulated CXCR4 levels and enhanced SDF-1-directed migration.

View Article: PubMed Central - PubMed

Affiliation: Division of Molecular Oncology, Institute for Experimental Cancer Research, CCC-North, University of Kiel, Kiel, Germany.

ABSTRACT
Despite improvements in detection, surgical approaches and systemic therapies, breast cancer remains typically incurable once distant metastases occur. High expression of TRAIL-R2 was found to be associated with poor prognostic parameters in breast cancer patients, suggesting an oncogenic function of this receptor. In the present study, we aimed to determine the impact of TRAIL-R2 on breast cancer metastasis. Using an osteotropic variant of MDA-MB-231 breast cancer cells, we examine the effects of TRAIL-R2 knockdown in vitro and in vivo. Strikingly, in addition to the reduced levels of the proliferation-promoting factor HMGA2 and corresponding inhibition of cell proliferation, knockdown of TRAIL-R2 increased the levels of E-Cadherin and decreased migration. In vivo, these cells were strongly impaired in their ability to form bone metastases after intracardiac injection. Evaluating possible underlying mechanisms revealed a strong downregulation of CXCR4, the receptor for the chemokine SDF-1 important for homing of cancers cells to the bone. In accordance, cell migration towards SDF-1 was significantly impaired by TRAIL-R2 knockdown. Conversely, overexpression of TRAIL-R2 upregulated CXCR4 levels and enhanced SDF-1-directed migration. We therefore postulate that inhibition of TRAIL-R2 expression could represent a promising therapeutic strategy leading to an effective impairment of breast cancer cell capability to form skeletal metastases.

No MeSH data available.


Related in: MedlinePlus