OBJECTIVE: To investigate the function of RAS protein on the progression of the T-ALL cell lines in vitro. METHODS: The DNA of the T-ALL cells was purified then amplified the coding regions of three RAS genes (KRAS, NRAS, HRAS) by PCR reaction. After T-A cloning, the coding regions of KRAS, NRAS and HRAS were sequenced by Sanger Sequencing. The siRNA oligonucleotides were cloned into the pSEH-361 vector, which were then packaged into retroviral together with pAMPHO and pVSVG in the HEK-293T cells. The T-ALL cells were infected with the retrovirus. The gene expressions were detected by qRT-PCR and Western blot. The T-ALL cells were stained with Annexin V-PE/7-AAD and the apoptotic cells were detected by flow cytometry. The T-ALL cells were stained with Hoechst 33258, and the cell cycle distribution was determined by flow cytometry. The expression of cleaved-Caspase 3 was stained with antibody and observed with fluorescence microscope. RESULTS: For RAS genes, beside the Loucy and the P12-ICH cells harbored KRAS c.6187G>A (p.KRAS^G12D) homozygous mutant, no missense mutation of RAS was found in other T-ALL cells genome. The pan RAS inhibitor compound 3144 showed toxicity to all tested T-ALL cells, except PEER (IC₅₀=47.916 μmol/L). Similarly, Tipifarnib induced apoptosis of multiple T-ALL cell lines except for the PEER cells (IC₅₀=94.2265 μmol/L). After KRAS knock-down, the T-ALL cells showed significant apoptosis and an arrested cell cycle. CONCLUSION The KRAS protein is vital for the progression of the T-ALL cells in vitro, it is a potential therapeutic target for T-ALL patients.
Apoptosis ; Cell Line ; Cell Proliferation ; Humans ; Mutation ; Precursor T-Cell Lymphoblastic Leukemia-Lymphoma ; Proto-Oncogene Proteins p21(ras)/genetics*

OBJECTIVE: To establish the technique that take the advantages of flow cytometry combined fluorescence in situ hybridization (Flow-FISH) to identify the Epstein-Barr virus(EBV) infected lymphocyte subtypies in patients' peripheral blood sample. METHODS: Peripheral Blood monocyte from 9 patients with EBV infection enrolled at Children's Hospital in Chongqing Medical University were isolated by Ficoll-paque centrifugal separation. The expressions of EBER1, EBER2 in cell were detected by qRT-PCR. The surface markers of cell were detected by Flow cytometry after staining with their antibodies. The cell was treated Fix-Permeabilization Buffer before hybridization with fluorescent labeled probe at 37 ℃ overnight. The cell status, surface markers and targeted mRNA are detected by flow cytometry and fluorescence microscope. RESULTS: It was optimized that the Fix-Permeabilization Buffer and recipe with 0.2% Tween-20 were picked out as providing a good cell integrity and high resolution of surface markers. Hybridization with 20% formamide and 7% dextran sulfate at 37 ℃ overnight is the optimal hybridization condition as a good hybridization effect, a detectable cell integrity and a high resolution of cell markers under flow cytometry detection. Finally, upon the established Flow-FISH method, lymphocyte subpopulations of the EBV⁺ cells from cell lines and blood samples of patients were identified successfully. CONCLUSION A Flow-FISH technology is established, which can be applied in the identification of EBV infected cell subtypes. This research provides a foundmental for its application in clinical test in EBV⁺ related proliferative diseases.
Epstein-Barr Virus Infections ; Flow Cytometry/methods* ; Herpesvirus 4, Human ; Humans ; In Situ Hybridization, Fluorescence/methods* ; Lymphocyte Subsets