ABSTRACT
Objective To assay and determine whether the human acute monocytic leukemia cell line THP-1 contains side populations (SP) cells,and to increase the proportion of SP cells using cytarabine (Ara-C).Methods Fluorescent microscope and flow cytometry (FCM) were employed for detecting the percentage of SP cells in THP-1 cells.Then,SP and non-SP (NSP) subpopulations were collected and identified.Finally,THP-1 cells were incubated with different concentrations of Ara-C for 24 hours and detected the proportion of SP cells,respectively.Results The results demonstrated that the percentage of SP cells was (1.81 ± 0.99) ％ in THP-1 cells.A majority of the SP cells remained in the G0/G1 phase,and the expressions of CD34 + and CD34 + CD38-and the proliferative ability of the SP cells were higher than those of NSP cells (P ＜ 0.05).The mRNA expression of multidrug resistance genes (ABCG2,ABCB1),apoptosis regulation genes (Bcl-2) and the Bcl-2/Bax ratio of SP cells were higher than those of NSP cells.SP cells have been shown to be more tumorigenic than NSP cells.After co-culture with Ara-C,the proportion of SP cells increased significantly and presented in a concentration-dependent manor.Conclusions All of these findings suggest that the THP-1 cell line contains SP cells and the SP cells possess some intrinsic stem cell properties.The proportion of SP cells can be increased when co-cultured with Ara C,and this technique is a useful and important application for the study of LSCs.
ABSTRACT
<p><b>OBJECTIVE</b>To study the prognostic significance of CD47 in a NOD/SCID mouse model of acute myeloid leukemia (AML) and the best strategy for targeted therapy for this disease.</p><p><b>METHODS</b>CD34(+)CD38(-) leukemia stem cells (LSCs) were separated and transplanted into NOD/SCID mice to establish a mouse model of acute monocytic leukemia (AMoL). Anti-human CD47 antibody, alone or combined with cytosine arabinoside (Ara-C), was used to treat the mice with AMoL for 7-14 days, and therapeutic efficacy was assessed. LSCs were cultured together with mouse macrophages in culture medium containing anti-CD47 or anti-CD45 monoclonal antibody for 2 hours, to observe the phagocytic ability of macrophages to LSCs.</p><p><b>RESULTS</b>CD34(+)CD38(-) LSCs existed among THP-1 cells, with a content of about (0.12 ± 0.06)%, and a mouse model of AML was successfully established after the purified CD34(+)CD38(-) LSCs (97.0% ± 1.7%) were transplanted into NOD/SCID mice. The in vivo experiment showed that mice with AMoL had the most significant decrease in CD33(+)CD45(+) leukemia cells in peripheral blood and bone marrow and survived the longest after being treated with Ara-C (7 days) plus anti-CD47 monoclonal antibody (14 days) (P < 0.01). After 2 hours of in vitro culture, the phagocytic index in the culture medium containing anti-CD47 monoclonal antibody was significantly higher than in the culture medium containing anti-CD45 monoclonal antibody (76.9% ± 12.2% vs 7.60% ± 2.4%; P < 0.05).</p><p><b>CONCLUSIONS</b>High expression of CD47 is an adverse prognostic factor in AML. Combination therapy with anti-CD47 monoclonal antibody and Ara-C can effectively eliminate leukemia cells and LSCs, demonstrating great clinical significance in curing AML.</p>
Subject(s)
Animals , Female , Humans , Male , Mice , Antibodies, Monoclonal , CD47 Antigen , Allergy and Immunology , Physiology , Cytarabine , Leukemia, Myeloid, Acute , Drug Therapy , Mortality , Pathology , Mice, Inbred NOD , Mice, SCID , PrognosisABSTRACT
<p><b>OBJECTIVE</b>To study the effectiveness and safety of immunosuppressive therapy (IST) in the treatment of childhood aplastic anemia (AA) and to study the main factors influencing the effectiveness.</p><p><b>METHODS</b>The clinical data of 55 children with severe aplastic anemia (SAA) and 51 children with chronic aplastic anemia (CAA) were retrospectively analyzed. All patients received IST from January 2007 to December 2010.</p><p><b>RESULTS</b>In children with CAA, the effective rate of antithymocyte globulin (ATG) plus cyclosporine A(CsA) combination therapy was significantly higher than that of CsA alone (80% vs 44%; P<0.05); in children with SAA, the effective rate of ATG plus CsA combination therapy was also significantly higher than that of CsA alone (75% vs 40%; P<0.05). No patients developed clonal disease such as myelodysplastic syndrome, paroxysmal nocturn hemoglobinuria or acute myelocytic leukemia. In patients treated with the ATG plus CsA combination therapy, the response rate was relatively high for children whose disease course was less than six months, bone marrow hematopoietic area was more than 40%, had no severe infections, and experienced granulocyte colony stimulating factor (G-CSF) reaction during the early treatment; however, it was not related to AA subtypes and age.</p><p><b>CONCLUSIONS</b>ATG plus CsA combination therapy is effective and safe in the treatment of childhood AA. The disease course, bone marrow hematopoietic area, severe infections and G-CSF reaction to early treatment are the main factors influencing the therapeutic effects.</p>