[Concordance of PD-L1 expression detected by two immunohistochemical platforms and antibodies]

Objective: To evaluate the concordance of PD-L1 expression in various tissues using antibodies 28-8 and SP263 on their respective detection platforms. Methods: Three hundred seventy four specimens of surgical resection of pulmonary diseases in the First Affiliated Hospital of Nanjing Medical University from January 1, 2012 to January 31, 2017 were collected. Totally 374 cases were tested for PD-L1 expression using the two antibodies, 28-8 and SP263, by respective detection platforms (Dako and Ventana). Finally, 336 cases were used for further evaluation, and the results were statistically analyzed for concordance. Results: For non-small cell lung carcinoma (NSCLC), the positive rate of PD-L1 was 57.5% (177/308) using SP263, and 57.5% (177/308) using 28-8 antibody. The correlation coefficient was 0.97 (P<0.01). The positive rate of both benign lung diseases and paracancerous tissues was about 10.7% (3/28), and the positive concordance rate was 100.0%. The distribution of both antibodies was also relatively consistent. Conclusions: The expression levels of 28-8 and SP263 antibodies in NSCLC and other tissues are relatively consistent, suggesting both antibodies may be complementary and substitute for each other, which may be useful in guiding clinical management.

[The role and mechanism of 2-deoxyglucose in reversing osimertinib-acquired resistance of non-small cell lung cancer cell line]

Objective: To explore the role and mechanism of 2-deoxyglucose (2-dg) in reversing osimertinib- acquired resistance of non-small cell lung cancer(NSCLC)cell line. Methods: The NSCLC line H1975 (purchased from the American Type Culture Collection) was conducted by induction method in vitro to construct the osimertinib-resistance NSCLC cell line H1975-OR. The osimertinib-resistance of H1975-OR cell line was examined by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, colony-formation assay, Ki67 incorporation assay and the expression of apoptosis-related protein. The glycolysis level was assayed by the lactic acid production measured in the culture medium supernatant of H1975 and H1975-OR. The expression of glycolysis key enzymes (HK2, GLUT1, P-PKM2) and apoptosis-related protein (BIM, Bcl-2) were detected by Western blot. The cells were divided into control group, 2-deoxyglucose (4 mmol/L) monotherapy group, osimertinib (3 μmol/L) monotherapy group and 2-deoxyglucose (4 mmol/L)+ osimertinib (3 μmol/L) combination therapy group, then the apoptosis rate of cells was measured by flow cytometry to evaluate the pro-apoptotic ability of drugs. Date were analyzed by Independent-Samples t-test using SPSS 16.0 statistical software. Results: The glycolysis level of osimertinib-sensitive cell line H1975 was lower than that of osimertinib-resistance cell line H1975-OR [the yield of lactic acid, respectively, was (21.0±0.9) and (26.5±2.8) mmol·L(-1)·10(4)cells(-1), P<0.05]. The osimertinib- acquired resistance of H1975-OR could be reversed by 4 mmol/L 2-deoxyglucose(the IC(50) value of osimertinib in H1975-OR cell line decreased from (7.0±1.9) μmol/L to (1.4±0.1) μmol/L, which was close to the IC(50) value of osimertinib in H1975 cell line (1.0±0.2) μmol/L. The apoptosis rate of H1975-OR was significantly higher in 2-deoxyglucose + osimertinib combination therapy group (26.7±2.4)%, compared to control group (5.1±0.7)%, 2-deoxyglucose monotherapy group (6.1±2.5)% and osimertinib monotherapy group (11.4±2.7)%(all P<0.05). The expression of pro-apoptotic protein BIM in H1975-OR was significantly higher in 2-deoxyglucose+ osimertinib combination therapy group (177.8±28.1)% and the expression of anti-apoptotic protein Bcl-2 in H1975-OR was significantly lower in 2-deoxyglucose+ osimertinib combination therapy group (24.6±5.2)%, compared to control group (100±0)%, all P<0.05. Conclusion: 2-deoxyglucose can reverse the acquired resistance of NSCLC cell line to osimertinib, which may be related to the inhibition of cell glycolysis and the induction of apoptosis.