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Objective @# To explore the effect of MPZL1 knockdown in A549 Taxol resistant (A549 / Tax) cells and whether it affect drug resistance and tumor cell stemness by regulating β-catenin．@*Methods @#A549 and A549 / Tax cells were treated with different concentrations of doxorubicin and paclitaxel to observe the differences in drug resist- ance between the two cells．Quantitative real-time PCR (qRT-PCR) and Western blot were used to detect the MP- ZL1 expression level in A549 and A549 / Tax cells． After knockdown or overexpression of MPZL1 in A549 / Tax cells，cells were divided into control group，small hairpin RNA negative control ( sh-NC) group，MPZL1 knock- down(sh-MPZL1) group，overexpression negative control ( OE-NC) group，MPZL1 overexpression ( OE-MPZL1) group．Cell counting kit-8 ( CCK-8 ) and clone formation assay were utilized to investigate cell proliferation and clone formation ablity．Western blot assay was used to detect the protein expression after the cells treated with Wnt / β-catenin signaling inhibitor XAV939 and activator CHIR-99201 . @*Results @# The half inhibitory concentration ( IC50 ) of doxorubicin and paclitaxel in A549 / Tax cells significantly increased compared to A549 cells(P＜0. 01) . MPZL1 presented a higher expression trend in A549 / Tax cells．The IC50 values of A549 / Tax for doxorubicin and paclitaxel were 2. 731 mg / ml and 4. 939 μg / ml after MPZL1 knockdown，compared to 4. 541 mg / ml and 13. 55 μg / ml in the NC group (P＜0. 01) ．The results of CCK-8 and clone formation assay showed that the knockdown of MPZL1 reduced the viability of cells proliferation and clonal formation ability (P＜0. 05) ．Western blot results in- dicated that the expression levels of MPZL1 protein，tumor cell stemness associated proteins ( CD44，CD133) ，β - catenin and multidrug resistance protein 1 (MDR1) ，lung resistance-related protein ( LRP) were significantly re- duced in the sh-MPZL1 group． Furthermore ，XAV939 could inhibit the expression levels of MPZL1 ，CD44， CD133，MDR1，LRP and β-catenin(P＜0. 01) ．The inhibitory effect of knockdown MPZL1 on the aforementioned proteins was significantly reversed by CHIR-99201 treatment．@*Conclusion @# MPZL1 is highly expressed in A549 / Tax cells．Knockdown MPZL1 suppresses the tumor cell stemness and proliferation，thereby reversing the drug re- sistance of doxorubicin and paclitaxel in A549 / Tax cells.
RESUMO
Objective@#To investigate the effect and mechanism of phosphoprotein phosphatase 5 catalytic(PPP5C) on the migration , invasion and tumor stemness of human lung adenocarcinoma H1299 cells.@*Methods@#The PPP5C⁃pcDNA3. 1 overexpression vector was constructed. PPP5C⁃pcDNA3. 1 and pcDNA3. 1 were transfected into H1299 cells , and H1299 stable cell lines were screened with G418. The mRNA and protein expression levels of PPP5C were identified by qRT⁃PCR and Western blot. The proliferation activity of H1299 cells was detected by drawing cell growth curve and cell clonal formation assay. The wound⁃healing assay and transwell assay were used to test the migration and invasion abilities of H1299 cells , respectively. The stemness of H1299 cells was evaluated by sphere formation assay.@*Results@#The PPP5C⁃pcDNA3. 1 eukaryotic expression vector was successfully constructed and the expression levels of PPP5C significantly increased after transfection into H1299 cells. After overexpression of PPP5C in H1299 cells , the cell growth curve and clonal formation assay displayed that the proliferation ability was not affected , the migration and invasion of cells were significantly enhanced through wound⁃healing assay and transwell assay , accompanied by an increase in the expression of MMP9 , stem cell spheroid assay showed a significant increase in stemness of cells , accompanied by increased expression of SOX2. @*Conclusion@#The proliferation ability of cells is not affected , the migration and invasion and the stemness of cells are enhanced by regulating MMP9 and SOX2 respectively , after overexpression of PPP5C in human lung adenocarcinoma H1299 cells.