LRRC25 plays a key role in all-trans retinoic acid-induced granulocytic differentiation as a novel potential leukocyte differentiation antigen

Leukocyte differentiation antigens (LDAs) play important roles in the immune system, by serving as surface markers and participating in multiple biological activities, such as recognizing pathogens, mediating membrane signals, interacting with other cells or systems, and regulating cell differentiation and activation. Data mining is a powerful tool used to identify novel LDAs from whole genome. LRRC25 (leucine rich repeat-containing 25) was predicted to have a role in the function of myeloid cells by a large-scale "omics" data analysis. Further experimental validation showed that LRRC25 is highly expressed in primary myeloid cells, such as granulocytes and monocytes, and lowly/intermediately expressed in B cells, but not in T cells and almost all NK cells. It was down-regulated in multiple acute myeloid leukemia (AML) cell lines and bone marrow cells of AML patients and up-regulated after all-trans retinoic acid (ATRA)-mediated granulocytic differentiation in AML cell lines and acute promyelocytic leukemia (APL; AML-M3, FAB classification) cells. Localization analysis showed that LRRC25 is a type I transmembrane molecule. Although ectopic LRRC25 did not promote spontaneous differentiation of NB4 cells, knockdown of LRRC25 by siRNA or shRNA and knockout of LRRC25 by the CRISPR-Cas9 system attenuated ATRA-induced terminal granulocytic differentiation, and restoration of LRRC25 in knockout cells could rescue ATRA-induced granulocytic differentiation. Therefore, LRRC25, a potential leukocyte differentiation antigen, is a key regulator of ATRA-induced granulocytic differentiation.

Prognostic significance of early assessment of minimal residual disease in acute myeloid leukemia with mutated NPM1 patients / 中华血液学杂志

Objective@#To explore prognostic significance of early assessment of minimal residual leukemia (MRD) in adult patients with de novo acute myeloid leukemia (AML) with mutated NPM1.@*Methods@#The response, NPM1 mutated transcript level after induction chemotherapy and the first 2 cycles of consolidation chemotherapy, disease-free survival (DFS) and overall survival (OS) in 137 patients with AML with NPM1 mutations of A, B and D were retrospectively analyzed.@*Results@#Data of 137 patients were collected, 67 were male, the median age was 49 years (16-67 years) , 107 (78.1%) had normal karyotype, 57 (41.6%) had positive FLT3-ITD mutation, the median NPM1 mutated transcript level at diagnosis was 84.1%. Among the 134 evaluable patients, 115 (85.8%) achieved a complete remission (CR) . Multivariate analyses revealed that WBC<100×109/L (OR=0.3, 95% CI 0.1-0.9, P=0.027) and first induction therapy with "IA10" protocol (OR=0.3, 95% CI 0.1-0.8, P=0.015) were factors associated with achieving a CR. With a median follow-up period of 24 months (range, 2 to 91 months) in 77 survived CR patients, the probabilities of DFS and OS at 3 years were 48.0% and 63.9%, respectively. Multivariate analyses showed that positive FLT3-ITD (HR=3.2, 95% CI 1.6-6.7, P=0.002) , high MRD level after 2 cycles of consolidation chemotherapy (NPM1 mutation transcript level <3-log reduction from the individual baseline, HR=23.2, 95% CI 7.0-76.6, P<0.001) and chemotherapy or autologous hematopoietic stem cell transplantation (auto-HSCT) rather than allogeneic HSCT (allo-HSCT) (HR=2.6, 95% CI 1.0-6.6, P=0.045) were the unfavorable factors affecting DFS, high MRD level at the time of achieving the first CR (NPM1 mutation transcript level <2-log reduction from the individual baseline, OR=2.5, 95% CI 1.0-6.1, P=0.040) and after 2 cycles of consolidation chemotherapy (HR=4.5, 95% CI 2.0-10.3, P<0.001) were the unfavorable factors affecting OS. Furthermore, DFS and OS rates at 3 years in those receiving chemotherapy or auto-HSCT were 39.7% and 59.1%, respectively; positive FLT3-ITD and high MRD level after 2 cycles of consolidation chemotherapy were independent factors associated with both shorter DFS (HR=3.5, 95% CI 1.6-7.6, P=0.002 and HR=8.9, 95% CI 3.8-20.7, P<0.001) and OS (HR=2.7, 95% CI 1.1-6.9, P=0.036 and HR=3.1, 95% CI 1.2-8.0, P=0.021) ; meanwhile, high MRD level at the time of achieving the first CR associated with shorter OS (HR=3.1, 95% CI 1.2-8.0, P=0.022) .@*Conclusion@#Positive FLT3-ITD mutation and high MRD level after induction or consolidation chemotherapy associated with poor outcomes in AML patients with mutated NPM1.

Inhibition of K562 cell growth and tumor angiogenesis in nude mice by antisense VEGF(121) cDNA transfection / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the effect of antisense vascular endothelial growth factor (VEGF)(121) cDNA transfection on the growth of K562 cells in nude mice.</p><p><b>METHODS</b>K562 cells transfected with the antisense (AS) or sense (S) VEGF(121) cDNA, and the vector (V, pcDNA3) alone were transplanted subcutaneously into nude mice and the growth of the transfected cells in vivo was investigated. The effects of transfected K562 cells on human bone marrow endothelial cells (BMEC) were analyzed by MTT assay, the microvessel density (MVD) in tumor mass by vWF immunohistochemistry stain.</p><p><b>RESULTS</b>K562/V tumor grew more slowly [(207.5 +/- 192.9) mm(3) vs (445.0 +/- 150.9) mm(3), P < 0.05] and K562/S tumor more rapidly than K562/V tumor did [(1 174.6 +/- 508.7)/mm(3) vs (445.0 +/- 150.9) mm(3), P < 0.01]. K562/S cell culture supernatant was more strongly in promoting the proliferation of BMEC than K562/V supernatant did, but K562/AS supernatant resulted in a marked decrease of the promoting effect as compared with K562/V's. The MVDs in K562/AS, K562/S, and K562/V tumors were [(11.0 +/- 7.6)/0.72 mm(2) vs (50.8 +/- 11.7)/0.72 mm(2) vs (18.9 +/- 7.0)/0.72 mm(2)], respectively.</p><p><b>CONCLUSIONS</b>Antisense VEGF(121) cDNA transfected K562 cells show growth retardation in transplanted nude mice, decrease of tumor MVD, and decrease of promoting BMEC proliferation capacity.</p>