Establishment of gefitinib resistant lung cancer cell line and changes of EGFR signaling pathway / 中国药理学通报

Aim To establish gefitinib resistant epidermal growth factor receptor(EGFR) mutant lung cancer cell lines and to explore the changes of downstream signaling pathway of EGFR. Methods Gefitinib concentration gradient method was used to induce the establishment of H3255 and HCC827 resistant cell lines, and CCK8 assay was used to detect the proliferation of gefitinib resistant cell lines H3255/GR and HCC827/ GR. Western blot was used to detect the changes of EGFR downstream signals in H3255, HCC827, H3255/GR and HCC827/GR cells. Results The proliferation of H3255/GR and HCC827/GR cells was significantly lower than that of non-drug resistant cells. The phosphorylation signal molecules p-AKT, p-ERK1/2 and p-STAT3 of H3255/GR and HCC827/ GR drug-resistant cell lines were no significantly changed compared with their non-drug-resistant cell lines. There was no significant change in the expression of p-STAT3 and p-ERKl/2 in H3255/GR cells treated with gefitinib, but the expression of p-AKT was significantly down-regulated, while gefitinib only slightly inhibited the expression of p-ERKl/2 in drugresistant H3255/GR cells. In HCC827/GR cells, p-AKT and p-STAT3 were not inhibited by gefitinib, while p-ERKl/2 was moderately inhibited. Conclusion There are significant differences in the signal mechanism of drug resistance between H3255/GR and HCC827/GR cell lines.

Adenoid cystic carcinoma cells produce exosomes that promote tumor cell proliferation / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the effect of exosomes released by adenoid cystic carcinoma (ACC) cell line SACC-83 on the proliferation of ACC cells.</p><p><b>METHODS</b>Exosomes were isolated from SACC-83 cell culture supernatants using total exosome isolation reagents. The whole-mount exosomes were characterized using transmission electron microscope and Western blotting. The exosomes were labeled with green fluorescent dye PKH67 and co-cultured with SACC-83 cells for 48 h, followed by staining with Alexa Fluor 594 phalloidin and DAPI to observe exosome uptake by the cells using laser scanning confocal microscopy (LSCM). The cell proliferation was assessed using MTT assay and wound healing assay, and the expressions of ERK and P-ERK in the co-cultured SACC-83 cells were detected using Western blotting.</p><p><b>RESULTS</b>The exosomes isolated from SACC-83 cells showed a size range of 30-100 nm and expressed the exosomal markers CD9, CD63 and TSG101. LSCM showed exosome uptake by SACC-83 cells, which exhibited accelerated proliferation and significantly enhanced P-ERK expression ( < 0.05) without significant changes in ERK expression.</p><p><b>CONCLUSIONS</b>SACC-83 cells produce exosomes that promote the tumor cell proliferation and enhances the cellular expression of P-ERK, suggesting a potential role of MAPK/ERK pathway activation in exosome-mediated acceleration of ACC cell proliferation.</p>