The Role Of PPAPDC1A On The Tumorigenicity And Metastasis Of Breast Cancer Cells In Nude Mice

BackgroundBreast cancer is the most common cancer in women,and the second most frequent cause of cancer-related deaths in women worldwide.Although the mortality of breast cancerhas decline due to the early detection and improved treatment,but metastasis is still the main cause of death in most patients with breast cancer.Phosphophosphatase type 2domain containing 1A(PPAPDC1A)belongs to phosphophosphatase type 2.The study found thatPPAPDC1 A can induce dephosphorylation of different substrates,participate in regulating cell proliferation and movement,and play an important role in signal transduction,which may be related to the occurrence and development of cancer.PPAPDC1 A is a differentially expressed gene between normal breast tissues and cancer tissues.However,the effect of PPAPDC1 A on the tumorigenicity and metastasis of breast cancer cells in nude micehave not been reported.ObjectivesBy constructing the over expression and knock out of PPAPDC1 A breast cancer cellslines,in vivo and in vitro experiments,analyze the influence of PPAPDC1 A on breast cancer cell proliferation,invasion and metastasis,further understanding the effect of PPAPDC1 A on tumorigenicity and metastasis of breast cancer cells in nude mice.Methods1.The molecular biology techniques were used to establish the breast cancer cell lines which with PPAPDC1 A overexpression and knockdown.real-time quantitativepolymerase chain reaction(qRT-PCR)and Western blotting were used to validate the constructed stable cell lines.2.The effects of PPAPDC1 A stable overexpression and knockdown on the proliferation and invasion ability of breast cancer cells in vitro were detected by CCK-8and Transwell experiments.3.The effects of PPAPDC1 A on the proliferation of breast cancer cells in vivo and the tumorigenicity of breast cancer cell lines in nude mice were detected by subcutaneous tumor formation test.4.Immunohistochemical staining was used to detect the expression of Ki-67 in each group of tumor tissues.5.The effects of PPAPDC1 A on the metastasis of MCF-7 cells and MDA-MB-231 cells were investigated by tail vein injection in nude mice.Results1.The experimental results of qRT-PCR and Western blotting showed that the mRNA and protein expressions of PPAPDC1 A in MCF-7-Vector and MCF-7 cell lines were significantly lower than those in MCF-7-PPAPDC1 A cell lines(P<0.05).2.The experimental results of qRT-PCR and Western blotting showed that the mRNA and protein expressions of PPAPDC1 A in MDA-MB-231 cells lines was significantly higher than that in MDA-MB-231-shPPAPDC1 A cell lines(P<0.05).3.The results of CCK-8 experiment showed that compared with the MCF-7 and MCF-7-Vector cells,the growth rate of MCF-7-PPAPDC1 A cell lines was significantly increased(P<0.05);on the contrary,the growth rate ofMDA-MB-231-shPPAPDC1 A cells was significantly lower than that of MDA-MB-231-shNC and MDA-MB-231 cell lines(P<0.05).4.The results of transwell invasion assay showed that the number of invasive cells in MCF-7-PPAPDC1 A cell lines was significantly higher than that in MCF-7-Vector cell lines(P<0.05),and the number of invasion cells in MDA-MB-231-shPPAPDC1 A cell lines was significantly less than that in MDA-MB-231-shNC cell lines(P<0.05).5.Compared with MCF-7-Vector group,MCF-7-PPAPDC1 A group had faster tumorgrowth and larger tumor volume(P<0.05).In contrast,MDA-MB-231-shPPAPDC1 A group showed slower tumor growth and smaller tumor volume than MDA-B-231-shNC group(P<0.05).6.The results of immunohistochemistry showed that the positive rate of Ki-67 in MCF-7-PPAPDC1 A group was significantly higher than that in control group(P<0.05),and the positive rate in MDA-MB-231-shPPAPDC1 A group was significantly lower than that in control group(P<0.05).7.The results of tail vein injection in nude mice showed that compared with theMCF-7-Vector group,the number of pulmonary metastases in MCF-7-PPAPDC1 A groupwas increased(P<0.05).Compared with MDA-MB-231-shNC group,the number of pulmonary metastases in MDA-MB-231-shPPAPDC1 A group was decreased(P<0.05).Conclusions1.PPAPDC1 A promotes invasion and proliferation of breast cancer cells;2.PPAPDC1 A promotes tumorigenicity and metastasis of breast cancer cell lines in nude mice.