Effects Of Imatinib And Rapamycin On MTOR/S6 Signal Transduction Pathway In CD33~+ Cell And Immunity Of T Cell In CML

Objective:1. To evaluate the changes of mTOR/S6 signal transduction pathway of CD33~+ cell in newly diagnosed chronic myeloid leukemia(CML), CML treated with imatinib, or be resistant to imatinib, and influence of rapamycin(RAPA) on it.2. To explore the effect of imatinib and RAPA on immunity of T cell in patients with CML.Methods:1. By flow cytometry, the contents of p-mTOR and p-S6 in CD33~+ cell, and IFN-γin CD3~+, CD3~+CD8- and CD3~+CD8~+T cell were detected in primary CML and normal control, respectively, before and after treatment with RAPA in vitro. 2. By flow cytometry, the contents of p-mTOR and p-S6 in CD33~+ cell and IFN-γin CD3~+, CD3~+CD8- and CD3~+CD8~+T cell were detected in the patients with CML in chronic phase treated with imatinib, or hydroxycarbamide and interferon (HU~+IFN), respectively, before and after treatment with RAPA in vitro. 3. By flow cytometry, the contents of p-mTOR and p-S6 in CD33~+ cell, and IFN-γin CD3~+, CD3~+CD8-, and CD3~+CD8~+ T cell were detected in patients resistant to imatinib before and after treatment with RAPA in vitro.Results:1. The contents of p-mTOR and p-S6 in CD33~+ cell in the primary CML were higher than that in the normal contro[l(9.53±7.87)%vs(2.43±2.54)%;P<0.05] ([7.64±3.17)%vs(1.21±1.44)%; P<0.05], could be reduced by RAPA in vitro [(9.53±7.87)%vs(3.64±3.29)%,p<0.05], [(7.64±3.17)%vs(1.85±2.51)%; P<0.05]. 2. There was no difference in the contents of IFN-γin CD3~+, CD3~+CD8-, CD3~+CD8~+ T cell between the primary CML and the normal controls [(11.08±12.05)%vs(13.31±8.33)%; P>0.05], [(8.66±6.34)%vs(10.39±5.59)%; P>0.05], [(15.29±10.01)%vs(17.77±11.61)%; P>0.05], could be decrease by RAPA in vitro [(11.08±12.05)%vs(5.77±5.91)%; P<0.05], [(8.66±6.34)%vs(4.83±5.18)%; P<0.05], [(15.29±10.01)%vs(9.74±8.85)%; P<0.05].3. The contents of p-mTOR in CD33~+ cell in the patients treated with imatinib were higher than that of the group with HU~+IFN [(10.61±13.70)%vs(3.67±4.59)%; P<0.05], could be reduced by RAPA [(10.61±13.70)%vs(3.86±8.99)%;P<0.05]. p-mTOR in CD33~+ cell exceeded the 95% confidence interval of primary CML in 25.7% of patients treated with imatinib, and it was reduced by RAPA [(29.89±14.89)%vs(8.26±15.45)%;P<0.05]. There were no difference in the contents of p-mTOR in CD33~+ cell between HU~+IFN group and the primary CML [(3.67±4.59)%vs(9.53±7.87)%,P<0.05].4. Compared to the primary CML, the contents of p-S6 in CD33~+ cell of the patients treated with imatinib was not significant diffenent ([7.64±3.17)%%v(s19.65±30.19);P>0.05], while it was lower in the patients treated with HU~+IFN [(7.64±3.17)%%vs(2.95±2.70);P<0.05]. p-S6 in CD33~+ cell exceeded the 95% confidence interval of primary CML in 25.7% of patients treated with imatinib, and it was reduced by RAPA [(44.48±19.43)%vs(10.53±12.39)%,P<0.05].5. The levels of IFN-γin CD3~+, CD3~+CD8- and CD3~+CD8~+T cell in the patients treated with imatinib were significantly higher than that of primary CML and the patients treated with HU~+IFN, respectively [(17.28±12.71)%vs(11.08±12.05)%; P<0.05], [(13.06±9.34)%vs(8.66±6.34)%; P<0.05], [(22.50±16.70)%vs(15.29±10.01)%; P<0.05]; [(17.28±12.71)%vs(10.05±8.23)%; P<0.05], [(13.06±9.34)%(6.56±5.53)%; P<0.05], [(22.50±16.70)%vs(12.53±10.43)%;P<0.05]; and could not be influenced by RAPA [(17.28±12.71)%vs(13.41±11.29)%; P>0.05], [(13.06±9.34)%vs(10.06±8.21)%; P>0.05], [(22.50±16.70)%vs(20.45±13.22) %; P>0.05].6. RAPA did not influence the expression of IFN-γin CD3~+, CD3~+CD8- and CD3~+CD8~+T cell in patients with higher levels of p-mTOR/p-S6 ([24.69±10.86)%v(s24.32±12.08)%;P>0.05], [(18.79±8.72)%vs(17.0±6.53)%;P>0.05], [(31.59±12.86)%vs(30.45±14.99)%;P>0.05].7. p-mTOR and p-S6 in CD33~+ cell exceeded the 95% confidence interval of the primary CML group were found in 2 cases (20%) in imatinib resistant group, and could be reduced by RAPA in vitro. RAPA did not influence the expression of IFN-γin CD3~+, CD3~+CD8- and CD3~+CD8~+T cell in these two patients.8. Combination RAPA and imatinib successfully treated one patient with refractory CML mayloid blast crisis.Conclusion:1. The mTOR/S6 signal transduction pathway in CD33~+ cell was activated in primary CML patients, also could be blocked by RAPA.2. In some patients treated with imatinib, the mTOR/S6 signal transduction pathway in CD33~+ cell was activated, also could be blocked by RAPA.3. In minority of patients resistant to imatinib, the mTOR/S6 signal transduction pathway in CD33~+ cell was activated, and it might participate the resistance to imatinib. RAPA could blocked it.4. Imatinib and RAPA might have no impact on the immunity of T cell of patients with CML.5. Combination RAPA and imatinib might be a noval choice of therapy to CML, especially to patients resistant to imatinib.