Spheroid formation induced by human lung adenocarcinoma cell line SPC-A1 and the tumorigenic ability of lung cancer stem cells

Hao Guang-jun; Liu Qing; Wang Juan; Ma Yan-e; Ding Yan-hui

doi:10.3969/j.issn.2095-4344.2015.23.013

Abstract：BACKGROUND:There is no clear conclusion on whether the lung cancer stem cels can induce to spheroid formation and have tumorigenicity. OBJECTIVE: To observe the spheroid formation induced by human lung adenocarcinoma cel line SPC-A1 and the tumorigenic ability of lung cancer stem cels. METHODS:SPC-A1 at proliferating phase was cultured in serum-free DF12 culture medium, and then recombinant human insulin-like growth factor-1, recombinant human epidermal growth factor, and recombinant human fibroblast growth factor-10 were added to induce spheroid cels. Immune fluorescence detection and PCR amplification were done to understand the expression of stem cel associated markers. NOD-SCID immunodeficient mice were subcutaneously implanted with lung spheroid cels to observe the tumor growth.In vivo fluorescence imager was used for radiography. RESULTS AND CONCLUSION:After 5-10 days, lung spheroid cels were harvested. RT-PCR results showed that lung spheroid cels were positive for CD24, CD221, CCSP and SP-C. In addition, the lung spheroid cels and purified CD24+, CD221+ lung cancer stem cels were both positive for TTF-1 of lung stem cels, OCT4 and Nanog of embryonic stem cels and TTF-1 of Bmi-1 lung stem cels. The fluorescence detection showed that over 80% lung spheroid cels expressed CCSP and OCT4; SPC-A1 cels had the characteristics of alveolar type II cels, and also expressed SP-C protein, but only about 5% of the cels expressed CCSP and OCT4. At 50 days after subcutaneous implantation of lung spheroid cels, in vivo fluorescence imaging showed that the diameter of tumor in mice was 1 cm, indicating human lung adenocarcinoma cel line SPC-A1 can induce the spheroid formation, and lung cancer stem cels rich in the cel spheres have the tumorigenic ability.