The Study Of High Tumorigenicity Of SHI-1, And Establishment Of As₂O₃ Resistant Cell Line, SHI-1/AS2, And The Mechanism Of Its Multiple Drug Resistance

1. The study of high tumorigenicity of SHI-1 and its mechanismObjective: to study the high tumorigenicity of SHI-1 and its mechanism. Methods: the tumorigenicity was evaluated by injected 4 groups of nude mice with the SHI-1 cell with different cell densities (1×10⁷, 5×10⁶, 2.5×10⁶, 1×10⁶/nude mice) subcutaneously; the sensitivities of SHI-1, K562, NB4 to the NK cell were tested by the thizolyl blue method (MMT); chromosome aberration was detected by karyotype analysis; the deletion of P53 gene was detected by FISH method; P53 gene mutation was detected by sequencing of the PCR products. Results: the tumorigenicity rates of groups 1 to 4 were 100%, 66.7%, 40% and 0%, respectively; the sensitivity of SHI-1 to NK cell was lower than that of K562 and NB4 under the effect and target ratio: 40:1, 20:1, 10:1; R band karyotype analysis revealed the karyotype of SHI-1 cell was: 46, XY, t(6;11)(q27;23), del(17)(pll)[20]; one P53 gene deletion was revealed by FISH method; one allele of the P53 gene mutation was confirmed by sequencing of the PCR products. Conclusion: the high tumorigenicity of SHI-1 in nude mice is stable and reliable. Its lower sensitivity to the NK cell and P53 gene function defect were the main cause of high tumorigenicity of SHI-1.2. Establishment of As₂O₃ resistant cell line, SHI-1/AS2, and its biologiccharactersObjective: to establish the AS₂O₃ resistant cell line SHI-1/AS2. Methods: to induce theresistance of SHI-1 to AS2O3 gradually by short-time co-culturing SHI-1 with AS2O3. After the establishment, the SHI-1/AS2 was co-cultured with luM AS2O3 to maintain its resistance; its resistant capability to AS2O3 was evaluated by thizolyl blue method (MMT); the preliminary study of biologic characters of the cell line SHI-1/AS2 was done by morphological, karyotypic and M-FISH analysis. Results: SHI-l/AS2's resistant capability to AS2O3 was 2.2 times more than that of SHI-1. SHI-1/AS2 kept same morphologic characters as SHI-1; R-band karyotypic and M-FISH analysis reveled SHI-1/AS2 with more complex chromosome aberrations than SHI-1. Conclusion: SHI-1/AS2 has the resistant capability to AS2O3 to a certain degree; SHI-1/AS2 carries more complex chromosome abreactions than SHI-1, which is relevant to its resistance to AS2O3.3. The Study on the mechanism of SHI-l/AS2's resistance to As2O3Objective: to investigate the mechanism of SHI-l/AS2's resistance to AS2O3 by using RQ PCR. Methods: to choose ten MDR related genes: BAX, Bcl-2, BCRP, FAS, GST-ji, LRP, MDR1, MGMT and MRP, and their expressions in SHI-1 and SHI-1/AS2 were tested by RQ-PCR. Results: comparing with SHI-1, Bcl-2 expression was upgrade, while other genes expressions were downgrade in SHI-1/AS2. Conclusion: the over expression of Bcl-2 in SHI-1/AS2 was considered relevant to its resistance to AS2O3.