Mechanism of Anti Apoptosis and Immune Evasion in Drug-Resistant Leukemia Cells Mediated by STAT3 / 中国实验血液学杂志

OBJECTIVE@#To investigate the mechanisms of anti-apoptosis and immune evasion in drug-resistant leukemia cells mediated by STAT3, further to explore the possible mechanism of leukemia relapse caused by minimal residual.@*METHODS@#Drug-resistance leukemia cell line was established by transfecting pcDNA3.1-STAT3 into K562 cells (K562/STAT3). The expression of STAT3, BAX and NKG2D ligands (MICA and ULBP1) in K562/-cells, K562/STAT3 were detected by Western blot and/or RQ-PCR. Cells apoptosis and the killing effect of NK cells on leukemia cells were detected by flow cytometry.@*RESULTS@#The expression of the total STAT3, STAT3 phosphorylation in K562/STAT3 was significantly increased, and P-gp mRNA expression was increased also significantly (P<0.005). In K562/STAT3 cells, the expression of pro-apoptotic BAX (P=0.005) was significantly lower, and the number of apoptotic cells (P=0.002) induced by adriamycin was significantly decreased as compared with those in K562/- cells. After K562/STAT3 cells were treated by STAT3 inhibitor (SH-4-54), the expression of BAX mRNA (P=0.017) was significantly higher and the number of apoptotic cells (P=0.005) was significantly increased. The MICA and ULBP1 mRNA expression in K562/STAT3 cells was significantly lower than that in K562/- cells, and also for MICA and ULBP1 protein (MICA and ULPB1 mRNA: P<0.0001, MICA protein: P=0.001, ULPB1 protein: P=0.022). After K562/STAT3 cells were treated with STAT3 inhibitor (SH-4-54), the expression of MICA mRNA and protein was increased (mRNA: P=0.001, protein: P=0.002), but ULBP1 mRNA and protein showed no significantly change (mRNA: P=0.137, protein: P=0.1905). The cytotoxicity of NK cells to K562/STAT3 cells was susceptible as compared with K562/- (P=0.002), but the cytotoxicity of K562/STAT3 cells to NK cell could be recovered by STAT3 inhibitor (P=0.006).@*CONCLUSION@#STAT3 phosphorylation can inhibits cell apoptosis and promotes cell immune escape. STAT3 inhibitors can promote the apoptosis of leukemia cells and increase their sensitivity to NK cells.

Analysis of RUNX1 Gene Mutation in Patients with Myelodysplastic Syndrome / 中国实验血液学杂志

OBJECTIVE@#To investigate the mutation of RUNX1 gene in patients with myelodysplastic syndrome (MDS) and its correlation with other gene mutations and some clinical parameters.@*METHODS@#The mutations of RUNX1, DNMT3A, TET2, IDH1/2, NPM1, FLT3-ITD and C-KIT in 170 patients with MDS were detected by direct and indirect sequencing of genomic DNA-PCR amplification products.@*RESULTS@#The RUNX1 mutation was found in 23 patients (13.5 %, 23/170). Among the 170 patients, other most frequent mutation was TET2 (11.2%, 19/170), followed by mutations in DNMT3A (9.4%, 16/170), NPM1 (8.2%, 14/170), IDH2 (4.1%, 7/170)、FLT3-ITD (2.9%, 5/170), IDH1 (1.7%, 3/170) and c-KIT (0.58%, 1/170). The most common coexisting mutations were TET2 (5/23). The RUNX1-mutated group showed significantly higher leukocyte levels, higher percentages of blast cells, higher incidences of leukemia transformation and lower platelet counts in comparison with RUNX1 non-mutation group (P＜0.05). whereas there were no statistically significant difference in age, MDS subtype, karyotype and hemoglobin level between 2 groups (P＞0.05). Seventeen patients harboring RUNX1 mutations were followed up and almost 47.05% (8/17) of the patients progressed into acute myeloid leukemia (AML). The rates of transformation into AML in ASXL1-mutation group was significantly higher than that in ASXLL- non-mutation group (47.05% vs 11.7%) (P=0.001).@*CONCLUSION@#The incidence of RUNX1 mutation is high in MDS patients. The RUNX1-mutated patients have higher leukocyte level, higher percentages of blast cells, higher incidences of leukemia transformation and lower platelet count.

Coexisting Mutations in IDH1/2-Mutated Acute Myeloid Leukemia / 中国实验血液学杂志

OBJECTIVE@#To explore the coexisting mutations in IDH-mutated acute myeloid leukemia(AML) and its relation with partial clinical parametrs.@*METHODS@#The exon 4 mutation of IDH1/2 gene was screened by using genome DNA-PCR combined with sanger sequencing, 51 targeted gene mutations in the patients with IDH1/2 mutation were detected by using high throughput DNA sequencing combined with sanger sequencing.@*RESULTS@#Among 358 patients, the IDH1/2 mutation was found in 46 cases including IDH1 mutation in 35 cases and IDH2 mutation in 11 cases, 97.87%(45/46) patients with IDH1/2 mutation simultaneously carried other gene mutations including 8(17.8%) cases with mutation of double gene, 17(37.8%) cases with mutation of 3 genes and 20(44.4%) cases with mutation of ≥ 4 genes. The mutation frequency of each patient averaged 3.52 times. In mutation of accompanied genes, the common genes were NPM1(n=29, 63.0%), next DNMT3A(n=25, 54.3%), FLT3-ITD(n=7, 15.2%), TET2(n=5, 10.9%) and NRAS(n=5, 10.9%). The average WBC level of patients with NPM1 mutation in IDH1 mutation group was higher than that of patients in wild type group(P<0.05). The complete remission (CR) rate of patients with DNMT3A mutation was significant lower than that of patients with wild type (30% vs 80%, P<0.01). The presence of ≥ 4 mutations was found to be significantly associated with higher white blood level than that in the patients with double mutations(P<0.05).@*CONCLUSION@#More than 95% AML patients with IDH1/2 mutation commonly show additional mutations. The number and the type of IDH coexisting mutations have certain effect on the clinical features and CR rate.

Roles of NKG2D in cytokine-induced killer (CIK) against hematological malignant cells lines / 中国实验血液学杂志

This study was purposed to investigate the CIK cell cytotoxicity to hematological malignant cell lines by interaction NKG2D receptors and corresponding ligands. The CIK cells was expanded from healthy individual with interferon (IFN)γ, CD3 monoclonal antibodies (mAb) and interleukin-2 (IL-2). The subset of lymphocyte and the expression of NK cell receptors on CIK cells was detected by flow cytometry; NKG2D ligand expression on hematological malignant cell lines was also analyzed by flow cytometry, the calcein acetoxymethyl ester (CAM) was used for labeling target cells, then the cytotoxicity of CIK cells to hematological malignant cell lines was detected by flow cytometry. The results showed that most of CIK cells expressed CD3 (97.85 ± 1.95%) , CD3(+)CD8(+) cells and CD3(+)CD56(+) cells increased significantly as compared with un-cultured cells (P < 0.001;P = 0.033). About 86% CIK cells expressed NKG2D receptor but no other NK receptors such as CD158a, CD158b and NCR. Different levels of NKG2D ligands were detected in hematological malignant cell lines U266, K562 and Daudi. CIK cells showed high cytotoxicity to these three different cell lines, and this cytotoxicity was partially blocked by treating CIK cells with anti-NKG2D antibody (U266 52.67 ± 4.63% vs 32.67 ± 4.81%, P = 0.008;K562 71.67 ± 4.91% vs 50.33 ± 4.91%, P = 0.007;Daudi 68.67 ± 5.04 vs 52.67 ± 2.60%, P = 0.024) . It is concluded that most of CIK cells express NKG2D receptor, interaction of NKG2D-NKG2D ligands may be one of the mechanisms, by which CIK cells kill hematological malignant cells.

Enhanced cytotoxicity against leukemia cells of natural Killer cells from cord blood after expansion in vitro / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the enhanced cytotoxicity against leukemia cells of natural Killer (NK) cells from cord blood (CB) after expansion in vitro.</p><p><b>METHODS</b>NK cells was expanded on a layer of trophoblast cells with irradiated K562-mb15-41BBL cell line for 21 days. The levels of receptors on NK cells were detected by flow cytometry. Cytotoxicity of expanded NK cells against leukemia cells and specific ligand of immunoglobulin like(Ig- liKe)receptors were assessed using 51Cr released assay.</p><p><b>RESULTS</b>There were no differences of inhibitory receptors expression between fresh NK cells and expanded NK cells [CD158a:(16.77±11.65)% vs(14.37±11.12)%, P>0.05; CD158b: (42.48±18.11)% vs (40.92±19.02)%, P>0.05; NKG2A: (70.20±18.43)% vs (78.90±13.69)%, P>0.05], but higher activated receptors expression on expanded NK cells [NKp30: (54.10±13.27)% vs (4.14±2.05)%, P<0.05; NKp44: (72.10±17.30)% vs (0.52±1.16)%, P<0.05; NKp46: (80.63±14.01)% vs (44.19±6.19)%, P<0.05; NKG2D: (97.50±2.55)% vs (72.25±14.35)%, P<0.05]. Expanded NK cells showed higher cytotoxicity against leuKemia cell lines than fresh NK cells [K562: (74.3±3.6)% vs (55.3±4.2)%, P<0.05; Raji: (60.6±5.0)% vs (12.0±3.6)%, P<0.05]. CD158a⁻ CD158b⁻ NK cells had higher cytotoxicity on four types of target cells, but CD158a⁺CD158b⁻ CB-NK cell had lower cytotoxicity on 221-Cw4 and 221-Cw3Cw4 cells. CD158a⁻ CD158b⁺ CB- NK cells had lower cytotoxicity on 221-Cw3 and 221-Cw3Cw4, but CD158a⁺CD158b⁺ CB-NK cells had higher cytotoxicity on 721- 221 cells.</p><p><b>CONCLUSION</b>Expression of activated receptors of expanded NK cells were up-regulated, but no changes of inhibitory receptors. Expanded NK cells showed high cytotoxicity against leukemia cells and kept the specificity of ligand of Ig-like receptors, which could be beneficial to cell-therapy for tumor.</p>

Analysis of IDH1 and IDH2 mutations in patients with acute myeloid leukemia / 中华血液学杂志

<p><b>OBJECTIVE</b>To explore the prevalence of IDH gene (IDH1 and IDH2) mutations, types of mutations in patients with acute myeloid leukemia (AML), correlation with the internal tandem duplication(ITD) mutation of FLT3 gene, NPM1 gene mutation and some clinical characteristics.</p><p><b>METHODS</b>The mutations of IDH1 and IDH2 gene at exon 4, NPM1 gene at exon 12 and FLT3-ITD at exon 14 and 15 in 163 newly diagnosed AML patients were detected by PCR amplification followed by direct sequencing of genomic DNA.</p><p><b>RESULTS</b>(1) IDH mutations were found in 25 patients (25/163), and all were heterozygous, of which IDH1 in 7 patients (4.29%) and IDH2 in 18 (11.04%). A total of 4 types of IDH1 mutations were identified (c.395G→A, p.R132H, n = 4; c.394C→A, p.R132S, n = 1; c.394C→G, p.R132G, n = 1; c.315C→T, n = 1). The IDH1 mutation caused substitutions of residue R132 except for one (c.315C→T). All IDH2 mutations caused changes of R140 (c.419G→A, p.R140Q, n = 18). The incidence of IDH2 mutation was significantly higher than that of IDH1 mutation (11.0% v 4.3%, P = 0.022). Both IDH1 and IDH2 mutation were detected in one patient, while IDH1 was synonymous substitution (c.315C→T). IDH-mutated cases showed a significantly higher frequency of concurrent FLT3-ITD mutation compared with wildtype cases (34.6% vs 11.9%, P = 0.003), so did IDH mutations concurrent NPM1 mutation vs NPM1 wildtype (28.1% vs 12.7%, P = 0.033), of which the frequency of concurrent NPM1 and FLT-ITD mutations cases with the IDH mutation was significantly higher than that of NPM1 and FLT-ITD negative (45.5% vs 11.7%, P = 0.002). IDH mutation incidence was significantly higher in normal karyotype cases than in abnormal ones (20.5% vs 5.8%, P = 0.020). Patients with IDH mutations were significantly older than wildtype patients(P < 0.001), whereas, there were no statistically significant differences in gender, peripheral blood (PB) count at diagnosis between two groups.</p><p><b>CONCLUSIONS</b>The incidence of IDH mutation is higher in patients with de novo AMLs, of which IDH2 mutation more frequently, and the patients associated with older age, normal karyotype at diagnosis. IDH mutation has a strong association with NPM1 and FLT3-ITD mutations, suggesting that IDH mutation has synergistic effect with the latter gene on leukemogenesis.</p>