Universality Of NCCCs-new Tumor Cell Subpopulation

Objective:To study whether new tumor cell subpopulation-NCCC(No/low cyclin cycle cells) universally exist in various kinds of tumors,and have similar characters.To find a bran-new method for base experiment and clinical chemotherapy resistance.Methods:Colon cancer cell line LOVO, breast cancer cell line MDA-231and lung cell line H-460were cultured in vitro, respectively gathered,counted and inoculated to left side thighs of nude mice along skin.After preliminary tumor formation, similar size tumors were selected and divided into four groups:Control group(Con);EGF group(EGF); Chemotherapy group(Chemo) and EGF+Chemotherapy group (EGF+Chemo). Corresponding treatments were administrated to the four groups and tumor size was measured with vernier caliper every day.After about fourteen days,nude mice were executed and tumors were weighted.Tumors of various systems were be made into cell suspension,a part of them directly were detected with FCM(flow cytometry) for cancer stem cells marker,other part fixed with ice alcohol(80%) and detected with FCM for the expression of cyclinA,cyclinBl,cyclinDl, cyclinE and Ki-67.Another part from Chemotherapy group and EGF+Chemotherapy group tumors were taken out for mading cell suspension in aseptic condition,counted,inoculated to left side thighs of nude mice along skin,and then tumor formation was observed. Results:LOVO, MDA-231and H-460came from three various cell lines which resulted in similar results as follows:1)In EGF group, cells with positive cancer stem cell markers decreased,expression of Ki-67increased,and cells in proliferative phase also increased;2)In chemotherapy group, tumors in nude mice growed slower,weight of tumors was lower,cells with positive cancer stem cell markers were higher,the expression of four major cyclins and Ki-67decreased,and cells in proliferative phase also decreased;3)In EGF+chemotherapy group, tumors in nude mice growed the slowest in four groups,weight of tumors was the lowest, cells with positive cancer stem cell markers were maximum, the expression of four major cyclins and Ki-67and cells in proliferative phase were minimum. The secondary tumor formation ability of residual tumors of EGF+chemotherapy group was stronger than that of Chemo group.Conclusions:In colon cancer cell line LOVO, breast cancer cell line MDA-231and lung cell line H-460, residual tuomor cells after chemotherapy combined with inducing cycle agents possess similar characters,which are characterized by tumor cell subpopulation-NCCC with low expression of four major cyclins and strong tumor formation ability.