| Nucleolus is one of the most important structure in eukaryotic cells commonly. It isthe sites of rDNA transcription and rRNA synthesis. If we think the ribosomal as the“molecular machine” for protein synthesis, then the nucleolus is the “mother ship”that creates this machine. In addition, the nucleolus also has other functions, includingnucleotide modification of some small RNAs and participation in signal recognitionparticles biosynthesis, especially in cell cycle and cellular senescence,etc. With thedomestic and foreign scholars study,nucleoli protein plays an important role inmalignant tumor.PES1is part of nucleolar protein, and was identified in themutational study of the embryonic development of Zebrafish. Its main biologicalfunctions include forming nucleolus and regulating cell cycle. Some researchesindicate the close relationship between PES1and tumorigenesis.In present research, we explored the regulating mechanisms of exogenous nucleoluslocalized protein PES1and the relationship between PES1and estrogen-receptor α inthe breast cancer.At first, We analysed the expression of PES1by Western blot in severalgynaecological tumer cell lines that we own at the moment. And PES1was detectedin breast cancer cell nuclear by Immunohistochemical assay and immunofluorescencemethod.For the second, we found that PES1’s protein levels were up-regulated whenexogenous estrogen was added into tumor cells, and PES1’s protein higher levelsshowed a positive correlation with the dose or time of treatment,especially in BICRand ZR75cells.Meanwhile, In ER-ɑ（+）cell lines, ER-ɑ can be knocked down inBICR and ZR75,constructing ER relative lower expression and monitoring PES1 expression level after estrogen stimulation.Through western blot,we identifyinterference efficiency with difference interference sites, and upon estrogenstimulation given, collecting new celles after24hours, contrasting protein of PES1the above. As a result,, PES1level is not changed after giving exogenous estrogenand knocking down ER-a in cells BICR and SKOV3.The third, in order to clarify correlation between ER-ɑ and PES1, three followingaspects has been carried out:①,ER-a were knocked down by siRNA in BICR, ZR75and SKOV3cell lines and then the PES1protein expression was detected by westernblot. As a result, PES1level was down-regulated when ER-a was knocked down andthis kind of phenomenon was reflected in all of the three cell lines.On the contrary, asPES1were knocked down in BICR,ER-a level was down-regulated. Therefore, it isconsidered that ER-ɑ and PES1have some correlation both positive and negativeaspects.②, In order to test ER to influence the stability of the PES1, ER-a wereknocked down in BICR and ZR75, CHX was introduced into two groups(InterferenceER and Not interference ER), Makig GAPDH as standard, contrasting PES1expression the above by Western Blotting. The datas show that the same concentrationunder the action of CHX,as time passes on, PES1was gradually in degradation ineach group, but the PES1degradation was obviously faster in interference ERexperimental group,Especially in breast cancer cell ZR75.③,The correlation betweenER-ɑ and PES1in BICR by Co-Immunoprecipitation show that the ER-ɑ antibodiescan bind with PES1protein and make it to decrease,it means that Endogenous ER andPES1can interact with each other in BICR.④,Apreliminary research concerning, biological function of PES1in breast cancercell showed that the flat cloning become weak obviously after the PES1was knockeddown in breast cancer cell. And we found that PES1could influence cell cycle ofbreast cancer in some degree.however, the phenomenon was not very obvious andneed to be further study.In a summary, estrogen can regulate nucleolar protein called PES1withestrogen-receptor α, and then in the process of PES1degradation,ER may delay degradation speed of PES1,which takes part in the stability of PES1. we find that thenucleolar protein PES1in breast cancer cell may reduce cells’ flat cloning. All in all,this research underlies a critical role of PES1in the development of breast cancer. |
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