PP4, one of the few protein phosphata- ses associated with centrosome in cells of many species such as Drosophila, C. elegans and mam- mals, plays an essential role in the regulation of cen- trosome functions in Droso...PP4, one of the few protein phosphata- ses associated with centrosome in cells of many species such as Drosophila, C. elegans and mam- mals, plays an essential role in the regulation of cen- trosome functions in Drosophila and C. elegans. In order to explore the role of PP4 in mammalian cells, full-length PP4 gene was obtained by RT-PCR from MCF7 cell total RNA and inserted into eukaryotic expression vector pEGFP-C1. The resultant con- struct pEGFP-C1-PP4 was transfected into MCF7 cells and immunostaining was carried out to confirm the centrosome localization of PP4. Then we re- versely subcloned a non-conserved domain of PP4 into pXJ41 to construct an anti-sense vector pXJ41- as-PP4. By transfecting pXJ41-as-PP4 into MCF7 cells and screening with G418, we obtained a stable cell line in which PP4 expression was stably sup- pressed. The cell line was analyzed on cell mor- phology, cytoskeleton structure, growth characteris- tics and the mitosis process. It was found that the proliferation rate decreased and serum-dependence increased in PP4-suppressed cells. Furthermore, flow cytometry and mitotic index analysis showed that G2/M transition was prolonged. PP4 suppression resulted in abnormal interphase microtubule, forma- tion of multipolar spindles and an increase in per- centage of multinuclear cells. These results sug- gested that PP4 is required for centrosome function in mammalian cells.展开更多
Genetic and molecular heterogeneity,together with intrinsic and acquired resistance to therapy,represent the major obstacles to the successful treatment of different types of breast carcinoma.Increasing evidence demon...Genetic and molecular heterogeneity,together with intrinsic and acquired resistance to therapy,represent the major obstacles to the successful treatment of different types of breast carcinoma.Increasing evidence demonstrates that SOX transcription factors in breast carcinomas could act both as oncogenes and tumor suppressors and have been associated with tumor stage and grade,poor prognosis,and therapy resistance.Both SOX2 and SOX18 overexpression has been correlated with poor prognosis in breast carcinomas,and these genes are recognized as potential antitumor targets.Our aim was to evaluate the effect of retinoic acid(RA),a well-known cyto-differentiating agent,on breast carcinoma cells in vitro and to investigate the potential of RA treatment to modify the expression of SOX2 and SOX18 genes.By applying various experimental approaches,we evaluated the effect of RA on basic cellular processes in SK-BR-3 and MCF7 breast carcinoma cell lines.We have shown that RA inhibits cell growth,reduces the number of Ki-67 positive cells,and causes cell-cycle arrest.RA effect was more prominent in SK-BR-3 cell line that lacks SOX2 expression,including a higher decrease in cell viability,reduction in colony formation,and significant remodeling of cellular structure.We have shown that RA treatment led to the downregulation of SOX2 expression in MCF7 cells and to the reduction of SOX18 expression in both cell lines.By functional analysis,we showed that the anti-proliferative effect of RA in both cell lines was not based on the activity of stemness marker SOX2,pointing to a SOX2-independent mechanism of action.The ability of RA to reduce SOX2/SOX18 expression raises the possibility that these genes can be used as biomarkers to distinguish RA-responders from non-responders.Together,our study shows that the response of breast carcinoma cell lines to RA treatment may vary,highlighting that the development of RA-based therapy should consider differences in breast carcinoma subtypes.展开更多
基金This work was supported by the National Natural Science Foundation of China （Grant No. 30270663）.
文摘PP4, one of the few protein phosphata- ses associated with centrosome in cells of many species such as Drosophila, C. elegans and mam- mals, plays an essential role in the regulation of cen- trosome functions in Drosophila and C. elegans. In order to explore the role of PP4 in mammalian cells, full-length PP4 gene was obtained by RT-PCR from MCF7 cell total RNA and inserted into eukaryotic expression vector pEGFP-C1. The resultant con- struct pEGFP-C1-PP4 was transfected into MCF7 cells and immunostaining was carried out to confirm the centrosome localization of PP4. Then we re- versely subcloned a non-conserved domain of PP4 into pXJ41 to construct an anti-sense vector pXJ41- as-PP4. By transfecting pXJ41-as-PP4 into MCF7 cells and screening with G418, we obtained a stable cell line in which PP4 expression was stably sup- pressed. The cell line was analyzed on cell mor- phology, cytoskeleton structure, growth characteris- tics and the mitosis process. It was found that the proliferation rate decreased and serum-dependence increased in PP4-suppressed cells. Furthermore, flow cytometry and mitotic index analysis showed that G2/M transition was prolonged. PP4 suppression resulted in abnormal interphase microtubule, forma- tion of multipolar spindles and an increase in per- centage of multinuclear cells. These results sug- gested that PP4 is required for centrosome function in mammalian cells.
基金the Ministry of Education,Science and Technological Development of the Republic of Serbia(Agreement No.451-03-9/2021-14/200042)the Serbian Academy of Sciences and Arts(Grant No.F24).
文摘Genetic and molecular heterogeneity,together with intrinsic and acquired resistance to therapy,represent the major obstacles to the successful treatment of different types of breast carcinoma.Increasing evidence demonstrates that SOX transcription factors in breast carcinomas could act both as oncogenes and tumor suppressors and have been associated with tumor stage and grade,poor prognosis,and therapy resistance.Both SOX2 and SOX18 overexpression has been correlated with poor prognosis in breast carcinomas,and these genes are recognized as potential antitumor targets.Our aim was to evaluate the effect of retinoic acid(RA),a well-known cyto-differentiating agent,on breast carcinoma cells in vitro and to investigate the potential of RA treatment to modify the expression of SOX2 and SOX18 genes.By applying various experimental approaches,we evaluated the effect of RA on basic cellular processes in SK-BR-3 and MCF7 breast carcinoma cell lines.We have shown that RA inhibits cell growth,reduces the number of Ki-67 positive cells,and causes cell-cycle arrest.RA effect was more prominent in SK-BR-3 cell line that lacks SOX2 expression,including a higher decrease in cell viability,reduction in colony formation,and significant remodeling of cellular structure.We have shown that RA treatment led to the downregulation of SOX2 expression in MCF7 cells and to the reduction of SOX18 expression in both cell lines.By functional analysis,we showed that the anti-proliferative effect of RA in both cell lines was not based on the activity of stemness marker SOX2,pointing to a SOX2-independent mechanism of action.The ability of RA to reduce SOX2/SOX18 expression raises the possibility that these genes can be used as biomarkers to distinguish RA-responders from non-responders.Together,our study shows that the response of breast carcinoma cell lines to RA treatment may vary,highlighting that the development of RA-based therapy should consider differences in breast carcinoma subtypes.
