Biological Characteristics Of The Side Population Of Human Small Cell Lung Cancer Cell Line H446

Objective:The aim of this study is to identify and characterize the side population (SP) cells in small cell lung cancer (SCLC) cell line H446, which lay the foundation for isolation and purification of CSC.Methods:Fluorescence-activated cel1 sorting (FACS) were used to sort SP and non-SP ( NSP ) cells from H446. Both subgroups were cultivated to survey the capability of reforming into suspended tumor cell spheres. Reverse-transcription PCR (RT-PCR) and real-time PCR were used to evaluate the mRNA expression levels of CD133, ABCG2 and Nucleostemin in both subgroups. The capacity of proliferation and the differences in drug resistance of both subgroups and unsorted cells was tested by MTT method. The differentiation ability of both subgroups was determined by FACS. The proliferation of them was determined by subcutaneous tumor formation in nude mice.Results:(1) The percentage of Hoechst33342 negative cells was about 5.1±0.2 % in H446 by fluorescence microscopy. The percentage of SP cells was 6.3±0.1% by flow cytometry.(2) SP cells has stronger capability of reforming into tumor spheres than NSP cells .(3) The mRNA expression levels of ABCG2, CD133 and nucleostemin in SP cells were 21.60±0.26, 7.10±0.14 and 1.02±0.08 fold higher than those in NSP cells (P<0.01, P<0.01 and P>0.05).(4) In vivo, SP cells showed a better proliferative ability and tougher viability when suffering with drug treatment.(5) SP cells can differentiate into NSP cells, but NSP can not differentiate into SP cells.(6) SP cells had a greater ability to form tumor. Conclusion:1.H446 cell lines contained a tiny minority of SP cells with stem cell properties.2.CD133, ABCG2 may be a cancer stem cell marker of SCLC.