Objective： BCR/ABL oncoprotein-expression is associated with uncontrolled cell growth. Sphingosine kinase 1 （SPK1） regulates the production of sphingosine 1-phosphate （S1P）, a key lipid signal molecular in cell p...Objective： BCR/ABL oncoprotein-expression is associated with uncontrolled cell growth. Sphingosine kinase 1 （SPK1） regulates the production of sphingosine 1-phosphate （S1P）, a key lipid signal molecular in cell proliferation and survival. The objective of this study was to elucidate the roles of S1P and its receptors in bcr/abl positive chronic myeloid leukemia （CML） cells. Methods： The expressions of SIP receptors： S1P1, S1P2 and S1P3 in CML cells were detected by RT-PCR. SPK1 expression, activity and extracellular S1P were determined in ECV304 and HL-60 cells which were transfected with bcr/abl gene. To elucidate the relationship between the BCR/ABL, ERK/MAPK （extracellular signal-regulated kinase/mitogen-activated protein kinase）, SPK/S 1P and S 1P/S 1 P2 signal pathways, bcr/abl positive CML cell line K562 was treated with STI571, PD98059, N,N-dimethyl sphingosine （DMS） and JTE-013. Results： Retrovirus-mediated overexpression of bcr/abl gene in ECV304 and HL-60 cells resulted in upregulation of the expression, activity of SPK1 and increase of the secretion of SIP, whereas treatment of STI571 and PD98059 decreased the BCR/ABL-induced S1P secretion. Treatment of DMS reduced S1P secretion and P42/44MAPK phosphorylation. S1P2-selective antagonist JTE-013 could also decrease P42/44MAPK phosphorylation. Conclusion： These results suggest that BCR/ABL up-regulates extracellular sphingosine 1-phosphate through sphingosine kinase 1 and there is cross-talk between SPK1/S1P/S1P2 and P42/44MAPK in bcr/abl positive CML cells.展开更多
Objective： Oncolytic adenovirus, also called conditionally replicating adenovirus （CRAD）, has been developed for the treatment of cancer. However, there is a tremendous need to enhance their antitumor efficacy. Her...Objective： Oncolytic adenovirus, also called conditionally replicating adenovirus （CRAD）, has been developed for the treatment of cancer. However, there is a tremendous need to enhance their antitumor efficacy. Here we wish to evaluate whether a strategy that combines the herpes simplex virus-thymidine kinase with oncolytic effects offers a therapeutic advantage. Methods： A novel adenovirus Ad-ETK containing a sequentially positioned promoter of human telomerase reverse transcriptase （hTERT）, the coding sequence of E1A gene, an internal ribosome entry site sequence （IRES） and the coding sequence of herpes simplex virus-thymidine kinase （HSV-TK） was constructed. Infection of various cells with Ad-ETK followed by RT-PCR confirmed the expression of E1A and HSV-TK. The oncolytic ability and synergism between oncolytic effects and HSV-TK system was measured. The infection efficiency was determined by flow cytometry. Results： Ad-ETK deliverys E1A and HSV-TK gene, which selectively replicates in hTERT-positive tumor cells, and the progeny virus can reach up to 150 IU/cell. Our in vitro study showed that Ad-ETK plus ganciclovir （GCV） induced an obvious cell death. Conclusion： An oncolytic adenovirus plus the HSV-TK/GCV suicide gene system resulted in a significant improvement in treatment efficacy and it may offer important considerations in the development and preclinical assessments of oncolytic virotherapy.展开更多
基金supported by the National Natural Science Foundation of China (No. 30570782).
文摘Objective： BCR/ABL oncoprotein-expression is associated with uncontrolled cell growth. Sphingosine kinase 1 （SPK1） regulates the production of sphingosine 1-phosphate （S1P）, a key lipid signal molecular in cell proliferation and survival. The objective of this study was to elucidate the roles of S1P and its receptors in bcr/abl positive chronic myeloid leukemia （CML） cells. Methods： The expressions of SIP receptors： S1P1, S1P2 and S1P3 in CML cells were detected by RT-PCR. SPK1 expression, activity and extracellular S1P were determined in ECV304 and HL-60 cells which were transfected with bcr/abl gene. To elucidate the relationship between the BCR/ABL, ERK/MAPK （extracellular signal-regulated kinase/mitogen-activated protein kinase）, SPK/S 1P and S 1P/S 1 P2 signal pathways, bcr/abl positive CML cell line K562 was treated with STI571, PD98059, N,N-dimethyl sphingosine （DMS） and JTE-013. Results： Retrovirus-mediated overexpression of bcr/abl gene in ECV304 and HL-60 cells resulted in upregulation of the expression, activity of SPK1 and increase of the secretion of SIP, whereas treatment of STI571 and PD98059 decreased the BCR/ABL-induced S1P secretion. Treatment of DMS reduced S1P secretion and P42/44MAPK phosphorylation. S1P2-selective antagonist JTE-013 could also decrease P42/44MAPK phosphorylation. Conclusion： These results suggest that BCR/ABL up-regulates extracellular sphingosine 1-phosphate through sphingosine kinase 1 and there is cross-talk between SPK1/S1P/S1P2 and P42/44MAPK in bcr/abl positive CML cells.
文摘Objective： Oncolytic adenovirus, also called conditionally replicating adenovirus （CRAD）, has been developed for the treatment of cancer. However, there is a tremendous need to enhance their antitumor efficacy. Here we wish to evaluate whether a strategy that combines the herpes simplex virus-thymidine kinase with oncolytic effects offers a therapeutic advantage. Methods： A novel adenovirus Ad-ETK containing a sequentially positioned promoter of human telomerase reverse transcriptase （hTERT）, the coding sequence of E1A gene, an internal ribosome entry site sequence （IRES） and the coding sequence of herpes simplex virus-thymidine kinase （HSV-TK） was constructed. Infection of various cells with Ad-ETK followed by RT-PCR confirmed the expression of E1A and HSV-TK. The oncolytic ability and synergism between oncolytic effects and HSV-TK system was measured. The infection efficiency was determined by flow cytometry. Results： Ad-ETK deliverys E1A and HSV-TK gene, which selectively replicates in hTERT-positive tumor cells, and the progeny virus can reach up to 150 IU/cell. Our in vitro study showed that Ad-ETK plus ganciclovir （GCV） induced an obvious cell death. Conclusion： An oncolytic adenovirus plus the HSV-TK/GCV suicide gene system resulted in a significant improvement in treatment efficacy and it may offer important considerations in the development and preclinical assessments of oncolytic virotherapy.
