Chemotherapy resistance research of lung cancer based on micro-fluidic chip system with flow medium

Micro total analysis systems (-TAS) or labs-on-achip, have been spreading rapidly due to their desirable characteristics, including reductions in reagent consumption, space requirements and analysis time. This work aimed at establishing an integrated microfluidic system which can supply the cells with fresh medium of oxygen and nutrition continuously at a control flow rate mimicking the microenvironment in vivo. Human non-small cell lung cancer cell line SPCA1 was seeded in a microchip supplied with fresh medium at a constant rate of 15 mm/24 h controlled by a pump. The expression of P-gp for verapamil-pretreated or non-pretreated cells was assayed with immunofluorescence. Both groups cells were exposed to anticancer drug VP-16 at 30 microM for 6 h before the apoptosis analysis online. The results indicated that the cells could grow and spread well for 4 days in the microfluidic system successively furnished with fresh medium. Immunofluorescence assay showed that the intensity of the fluorescence for the verapamil-pretreated cells was obvious weak compared with that of nonpretreated cells. Apoptosis analysis demonstrated that the percentage of apoptotic cells for verapamil-pretreated group increased around twofold compared with that of nonverapamil pretreated group (26.5+/-2.5% versus 10.9+/- 0.85%, p<0.05), showing a similar results as by flow cytometry analysis. All these indicate that P-gp plays an important role in the resistance to VP-16 in SPCA1, the microfluidic system provides a suitable environment for cells survival and is valuable in long time cell culture and bioassays mimicking the microenvironment in vivo and deserved to be studied further.