Expression of Nucleostemin gene in tumor cells derived from human embryomic bone marrow mesenchymal stem cells

Abstract

Objective To study role of bone marrow mesenehyme stem cells in tumor formation.Methods Nude mice (n = 18) were randomly divided into two groups.Mice in the control group were subcutaneously injected with human embryonic MSCs, and F6 cells were injected into the nine mice of the experimental group.Three mice were sacrificed to remove tumor tissue, which was then prepared for real-time BT-PCR detection at 4 (F6-4), 6 (F6-6) and 7 (F6-7) weeks, respectively.Human lung cancer tissue samples and adjacent non-malignant lung tissue samples were collected from 4 lung cancer patients.The difference between gene expression of F6 cells and MSCs was distinguished by fluorescent differential display (FDD) and verificated by PCR and the western blot analysis. Real-time fluorescent quantitative reverse transcription polymerase chain reaction (FQ-BT-PCR) was used to detect gene expression in tumor tissues after tumorigenesis in nude mice.A new tumor cell line, denominated F6, was established from mutated human embryonic bone marrow mesenchymal stem cells (MSCs) which were induced by the GMCSF and IL-4 in vitro.Results FDD analysis confirmed that cyelin Ⅰ was positively up-regulated in F6 cells compared with MSCs. Similar results were obtained by PCR and western blot.The cyclin Ⅰ gene expression levels in MSCs, F6, F6-4, F6-6 and 176-7 were significantly different(F=12.29 ,P ＜ 0.01).The cyclin Ⅰ gene expression level in F6(4.49±0.40) was 112 folds higher than those of MSCs(0.04±0.02,P＜0.01).Expression levels in F6-4 , F6-6 and F6-7 tissue were 1.82±0.80,3.30±0.43,3.68±1.67 which were significantly higher than that in MSCs (P＜0.05 or ＜0.01).The expression of cyclin Ⅰ increased significantly alone with the accreting volume of tumor.The expression levels of cyelin Ⅰ in human lung cancer tissues in four patients were 0.15±0.02, 0.58±0.23, 4.82±1.12, 1.21±0.60,respectively, and were significantly higher than that in adjacent non-malignant lung tissues (0.04±0.02,0.09±0.04,0.94±0.74,0.15±0.08) (F=12.39,P＜0.01).The protein expression level of cyclin Ⅰ in F6 cells was 0.32±0.08, which was 3.6-fold higher than that in MSCs (0.09±0.06, t=3.86,P＜0.05).Conclusions The expression level of cyclin Ⅰ in tumor tissue is higher during the entire course of tumorigenesis.Cyclin Ⅰ might be one of the factors playing important roles during tumorigenesis,especially in MSCs mutation. Key words: Neoplasms; Mesenchymal stem cells; Cyclins