To explore the mechanisms by which AKR1C3 induces tumor resistance, human breast cancer cell strain MCF-7/DOX resistant to doxorubicin, MCF-7/ AKR1C3 cells for overexpression of AKR1C3 and MCF-7/DOX-KD cells for knockdown of AKR1C3 in MCF-7/DOX cells were established. Western blot analysis found that AKR1C3 was expressed at a higher level in MCF-7/DOX than MCF-7 wild type cells. Similarly, CCK-8 and DAPI confirmed that MCF-7/ AKR1C3 cells were more resistant to DOX than AKR1C3 wild types as the IC50 was increased 6 times in MCF-7/AKR1C3 cells more than in AKR1C3 wild type cells. Meanwhile, colony formation ability was also enhanced after AKR1C3 was over-expressed in MCF-7 cells.Cytoplasmic/nuclear separation analysis and IF further found that β-catenin nuclear translocation mediated by AKR1C3 was the main reason contributing to the occurrence of DOX-resistant breast cancer cells. β-catenin inhibitor, XAV939, could reverse the AKR1C3 induced doxorubicin resistance in MCF-7 cells.Results indicated that AKR1C3 could be a potential therapeutic target in breast cancer cells.

BACKGROUND: The lack of pathological quality control standard in detecting epidermal growth factor receptor (EGFR) gene mutation in malignant pleural effusion leads to confusion in the interpretation of detection results and the clinical use of EGFR-tyrosine kinase inhibitor (TKI). Therefore, it is very important to propose quality control standards and guide the detection of EGFR mutation in pleural effusion. The aim of this study is to retrospectively analyze the results of EGFR gene mutation in pleural effusion sediment section according to strict pathological quality control standards, and the therapeutic effect of EGFR-TKIs guided by this detection results. METHODS: From January 2012 to June 2018, the clinical data of patients with pleural effusion collected from Department of Pathology of Peking Union Medical College Hospital were analyzed retrospectively. Among them, 132 patients with relatively complete clinical data and with EGFR gene mutation detection of paraffin-embedded pleural effusion sediment section according to the established quality control standard were included. According to the results of EGFR gene mutation, it was divided into positive group and negative group, and the efficacy of EGFR-TKIs in different groups was compared. RESULTS: After the centrifugation of pleural effusion, the sediment was embedded in paraffin, sectioned, and observed under the microscope after HE staining. If the number of tumor cells ≥100, it met the pathological quality control standard, and it could be used for subsequent EGFR gene mutation detection. EGFR gene mutations were detected in 72 (54.5%) of 132 patients. EGFR-TKIs were used in 69 of 72 mutation positive patients. Of 60 EGFR mutation negative patients, only 15 used EGFR-TKIs. In EGFR mutation positive group, the disease control rate (DCR) was 95.8%, and the median progression-free survival (PFS) was 11 months. In EGFR mutation negative group, the DCR was 0%, and the median PFS was 1 month. The DCR and PFS were significantly different between the two groups (P<0.05). CONCLUSIONS According to the pathological quality control standards, the embedded section of pleural fluid sediment can be used to detect EGFR gene mutation, and the results can be used to guide the clinical use of EGFR-TKIs.