Erythropoietin enhances migration of human neuroblastoma cells: in vitro studies and potential therapeutic implications

Abstract

The erythropoietin receptor (EpoR) is expressed by cells from the erythroid lineage; however, evidence has accumulated that it is also expressed by some other non-hematopoietic tissues including several solid tumor cells and proposed candidates for cancer stem cells. This is an important concern, because recombinant erythropoietin (EPO) is frequently employed in cancer patients as a drug to ameliorate anemia related to chemo/radiotherapy. In our studies, we employed three human neuroblastoma (NB) cell lines and found in all of them the expression of EpoR and EPO mRNA. The functionality of EpoR in RMS cell lines was evaluated by chemotaxis, adhesion, and direct cell proliferation assays. We noticed that all three human NB cell lines responded to EPO stimulation by enhanced chemotaxis and cell adhesion. However, at the same time we did not observe any significant effect of EPO on proliferation. Based on this EPO supplementation in NB patients employed because of radio/chemotherapy induced anemias may have an unwanted side effect on tumor metastasis.

Keywords: erythropoietin (EPO); erythropoietin receptor (EpoR); metastasis; neuroblastoma.

Figure 1. Panel A - mRNA for EpoR and EpO is expressed in human neuroblastoma (NB) cell lines

Expression of EpoR and EPO at the mRNA level by NB cells was assessed by RT-PCR. Representative results are shown. Panel B – EPO activates phosphorylation of phospho-Akt^ser473 and phospho-MAPK^44/42 signaling in HTB11 cells. Cells were non-stimulated (negative control) or stimulated for 5 min with FBS (positive control) or stimulated for 5min with EPO (0.5 or 20 iU/ml). Representative results are shown.

Figure 2. Erythropoietin (EPO) enhances migration of human NB cell lines

Effect of EPO (0.5, 5 or 20 iU/ml) on the chemoattraction of NB cells across Transwell membranes covered with gelatin. Combined data from three independent experiments are shown. *p≤0.05, **p≤0,01.

Figure 3. Erythropoietin (EPO) enhances adhesion of human NB cell lines

Effect of EPO (0.5, 5 or 20 iU/ml) on adhesion of RMS cells to fibronectin. Combined data from three independent experiments are shown. *p≤0.05, **p≤0,01.

Figure 4. Effect of EPO on proliferation of human NB cells

Effect of EPO (0.5 and 20 iU/ml) on proliferation of the HTB11, CRL2266 and CRL2271 cell lines. Data from three independent experiments are combined. p<0.05.