RESUMO
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 expression of MPZL1 in gastric cancer tissues, its relation with the prognosis, and its effects on proliferation and colony formation of gastric cancer. Methods GEPIA and UALCAN databases were used to analyze the expression of MPZL1 in various malignant tumors. The KM Plotter database and UALCAN database were used to analyze the effect of MPZL1 on the overall survival of gastric cancer patients. The expression of MPZL1 protein and the changes of apoptosis-related proteins in gastric cancer cells were detected by Western blot, and the effects of MPZL1 expression on cell proliferation and colony formation were detected by CCK-8 and colony formation assay, respectively. Results MPZL1 was found to be highly expressed in various malignant tumors by GEPIA database. The results of UALCAN and KM Plotter databases analysis showed that MPZL1 was highly expressed in gastric cancer tissues, and might be correlated with the overall survival of gastric cancer patients. The results of CCK-8 and colony formation assay showed that the overexpression of MPZL1 promoted the proliferation and colony formation ability of gastric cancer cells (P < 0.05). Western blot results showed that compared with control group, the expression levels of pro-apoptotic proteins Bad and Caspase-7 in the overexpression group were significantly lower while those in knockdown group were higher. Conclusion MPZL is highly expressed in gastric cancer tissues and promotes the proliferation and colony formation of gastric cancer cells, which may be related to the inhibition of apoptosis.