Granulocyte colony-stimulating factor inhibits CXCR4/SDF-1α signaling and overcomes stromal-mediated drug resistance in the HL-60 cell line

Study on the mechanism of CXCL12/CXCR4-axis-mediated upregulation of IL-8 and IL-6 on the biological function of acute T lymphocyte leukaemia cells

Blocking the CXCL12/CXCR4 axis can alter the biological functions of leukaemia cells. We hypothesise that interleukin (IL)-8 and IL-6 play an important role in this process. To test this hypothesis, we established a co-culture model of leukaemia cells and bone marrow stromal cells. Treatment of cells with AMD3100, a CXCR4 antagonist, and G-CSF blocked the CXCL12/CXCR4 axis, inducing biological changes in the leukaemia cells and altering IL-8 and IL-6 levels. Subsequently, after stimulating the CXCL12/CXCR4 axis, specific pathway blockers were employed to assess the role of four candidate signalling pathways in this process. ELISA results confirmed that MG-132 (10 μm) inhibits IL-8 expression and that the NF-κB signalling pathway contributes to this effect. Moreover, treatment with Perifosine, an AKT inhibitor, inhibited IL-6 expression. In addition, changes in the NF-κB signalling pathway inhibited IL-8 expression. Treatment with SP600125, a Jun N-terminal kinase inhibitor, and Perifosine also inhibited IL-8 expression; however, this effect occurred later. IL-6 expression was also lower in the Perifosine group; hence, inhibiting the PI3K/AKT signalling pathway can reduce IL-6 expression. This process requires the participation of multiple signalling pathways to regulate IL-8 and IL-6 expression. Therefore, the associated mechanism is likely to be highly intricate, with potential cross-effects that may impact leukaemia pathogenesis. IL-6 and IL-8 are physiologically regulated by the CXCL12/CXCR4 axis, while the NF-κB and JNK/AP-1 pathways are required for IL-8 expression in T-cell acute lymphoblastic leukaemia. Accordingly, by upregulating IL-8, the bone marrow microenvironment and CXCL12/CXCR4 axis may contribute to T-cell acute lymphoblastic leukaemia pathogenesis.

Combination regimen of granulocyte colony-stimulating factor and recombinant human thrombopoietin improves the curative effect on elderly patients with leukemia through inducing pyroptosis and ferroptosis of leukemia cells

Leukemia ranks as the one of most common causes of death from tumor. 51.4% of patients with leukemia are over 65 years old. However, the median overall survival (OS) of elderly leukemia patients is less than one year. It is urgent to explore more effective treatments for elderly patients with leukemia. Our recent prospective phase II single-arm study has revealed that combination regimen of granulocyte colony-stimulating factor (G-CSF) and recombinant human thrombopoietin (rhTPO) could improve the curative effect on elderly patients with leukemia, yet the precise mechanism remains unknown. This study demonstrated that combination of G-CSF and rhTPO showed greater effect on suppressing leukemia growth than G-CSF or rhTPO alone in vitro and in vivo. Mechanistically, G-CSF induced pyroptosis through ELANE in leukemia cells. Besides, rhTPO triggered ferroptosis by EP300 in leukemia cells. Moreover, rhTPO suppressed glutathione peroxidase 4 (GPX4) expression to induce ferroptosis through blocking the interaction between EP300 and GPX4 gene promoter via associating with EP300. In summary, this study illuminated that combination regimen of G-CSF and rhTPO improved the curative effect on elderly patients with leukemia through inducing pyroptosis and ferroptosis of leukemia cells. Therefore, our results provided a theoretical basis for combination regimen of G-CSF and rhTPO treating leukemia and potential therapeutic targets for leukemia.

Alterations in microRNA Expression during Hematopoietic Stem Cell Mobilization

Simple Summary

Lymphoproliferative disorders comprise a heterogeneous group of hematological malignancies characterized by abnormal lymphocyte proliferation. Autologous hematopoietic stem cell transplantation plays a very important role in the treatment of lymphoproliferative diseases. The key element in this process is the effective mobilization of hematopoietic cells from the marrow niche to the peripheral blood. Mobilization of HSC is regulated by many factors, out of which miRNAs present in the hematopoietic niche via targeting cytokines, and signaling pathways may play an important regulatory role. This study investigated the expression of selected miRNAs in patients with multiple myeloma, Hodgkin’s lymphomas, and non-Hodgkin’s lymphomas undergoing mobilization procedures. The aim of the study was to evaluate the expression of hsa-miR-15a-5p, hsa-miR-16-5p, hsa-miR-34a-5p, hsa-miR-126-3p, hsa-miR-146a-5p, hsa-miR-155-5p, and hsa-miR-223-3p during the mobilization procedure, and to assess their role in mobilization efficacy. The level of miRNAs was tested at two time points before the initiation of mobilization and on the day of the first apheresis. Our results suggest that the investigated miRNAs, especially hsa-miR-146a-5p, may influence the efficacy of HSC mobilization.

Abstract

microRNAs play an important role in the regulation of gene expression, cell fate, hematopoiesis, and may influence the efficacy of CD34+ cell mobilization. The present study examines the role of hsa-miR-15a-5p, hsa-miR-16-5p, hsa-miR-34a-5p, hsa-miR-126-3p, hsa-miR-146a-5p, hsa-miR-155-5p, and hsa-miR-223-3p in the course of hematopoietic stem cell mobilization. The numbers of CD34+ cells collected in patients with hematological malignancies (39 multiple myelomas, 11 lymphomas) were determined during mobilization for an autologous hematopoietic stem cell transplantation. The miRNA level was evaluated by RT-PCR. Compared to baseline, a significant decline in hsa-miR-15a-5p, hsa-miR-16-5p, hsa-miR-126-3p, hsa-miR-146a-5p, and hsa-miR-155-5p was observed on the day of the first apheresis (day A). An increase was observed only in the expression of hsa-miR-34a-5p. On day A, a negative correlation was found between hsa-miR-15a-5p and hsa-miR-146a-5p levels and the number of CD34+ cells in peripheral blood. A negative correlation was observed between hsa-miR-146a-5p and the number of collected CD34+ cells after the first apheresis. Good mobilizers, defined according to GITMO criteria, demonstrated a lower hsa-miR-146a-5p level on day A than poor mobilizers. Patients from the hsa-miR-146a-5p “low expressors” collected more CD34+ cells than “high expressors”. Our results suggest that the investigated miRNAs, especially hsa-miR-146a-5p, may influence the efficacy of HSC mobilization.

Antifade Carbon Dots on a Plasmonic Substrate for Enhanced Protein Detection in Immunotherapy

Fluorescence microscopic analysis of checkpoint protein expression is capable of predicting clinical outcomes for checkpoint blockade immunotherapy. However, accurate detection of their expression levels is hindered by fluorophore photobleaching and cell autofluorescence. We now develop a sensitive and robust fluorescence microscopy method that uses antifade graphite-structured carbon dots (GCDs) on a plasmonic Ag substrate (named ACPAS) for the accurate detection of checkpoint proteins in immunotherapy. In ACPAS, a Ag substrate is used to enhance the fluorescence of GCDs while a continuous illumination is implemented to quench cell autofluorescence, thus enabling a dramatic improvement in the signal-to-background ratio by up to 33-fold. We use ACPAS to monitor programmed death ligand-1 (PD-L1) expression levels on various tumor cells and finely differentiate their microscopic changes in combination with chemokine receptor CXCR4-targeted treatments. ACPAS analysis reveals for the first time that CXCR4 agonist (SDF-1α) and antagonist (AMD3100) can potentiate PD-L1 expression by down-regulating CXCR4 expression on tumor cells, which provides valuable information on the development of anti-PD-L1 and anti-CXCR4 combination therapy. We envision that ACPAS will become a broadly useful tool for protein expression studies in biomedicine and life sciences.

Ecological principle meets cancer treatment: treating children with acute myeloid leukemia with low-dose chemotherapy

Standard chemotherapy regimens for remission induction of pediatric acute myeloid leukemia (AML) are associated with significant morbidity and mortality. We performed a cohort study to determine the impact of reducing the intensity of remission induction chemotherapy on the outcomes of selected children with AML treated with a low-dose induction regimen plus granulocyte colony stimulating factor (G-CSF) (low-dose chemotherapy (LDC)/G-CSF). Complete response (CR) after two induction courses was attained in 87.0% (40/46) of patients receiving LDC/G-CSF. Post-remission therapy was offered to all patients, and included standard consolidation and/or stem cell transplantation. During the study period, an additional 94 consecutive children with AML treated with standard chemotherapy (SDC) for induction (80/94 (85.1%) of the patients attained CR after induction II, P = 0.953) and post-remission. In this non-randomized study, there were no significant differences in 4-year event-free (67.4 vs. 70.7%; P = 0.99) and overall (70.3 vs. 74.6%, P = 0.69) survival in the LDC/G-CSF and SDC cohorts, respectively. After the first course of induction, recovery of white blood cell (WBC) and platelet counts were significantly faster in patients receiving LDC/G-CSF than in those receiving SDC (11.5 vs. 18.5 d for WBCs (P < 0.001); 15.5 vs. 22.0 d for platelets (P < 0.001)). To examine the quality of molecular response, targeted deep sequencing was performed. Of 137 mutations detected at diagnosis in 20 children who attained hematological CR after two courses of LDC/G-CSF (n = 9) or SDC (n = 11), all of the mutations were below the reference value (variant allelic frequency <2.5%) after two courses, irrespective of the treatment group. In conclusion, children with AML receiving LDC/G-CSF appear to have similar outcomes and mutation clearance levels, but significantly lower toxicity than those receiving SDC. Thus, LDC/G-CSF should be further evaluated as an effective alternative to remission induction in pediatric AML.

OncomiR or antioncomiR: Role of miRNAs in Acute Myeloid Leukemia

Acute Myeloid Leukemia (AML) is a hematopoietic progenitor/stem cell disorder in which neoplastic myeloblasts are stopped at an immature stage of differentiation and lost the normal ability of proliferation and apoptosis. MicroRNAs (miRNAs) are small noncoding, single-stranded RNA molecules that can mediate the expression of target genes. While miRNAs mean to contribute the developments of normal functions, abnormal expression of miRNAs and regulations on their corresponding targets have often been found in the developments of AML and described in recent years. In leukemia, miRNAs may function as regulatory molecules, acting as oncogenes or tumor suppressors. Overexpression of miRNAs can down-regulate tumor suppressors or other genes involved in cell differentiation, thereby contributing to AML formation. Similarly, miRNAs can down-regulate different proteins with oncogenic activity as tumor suppressors. We herein review the current data on miRNAs, specifically their targets and their biological function based on apoptosis in the development of AML.

Effect of co‑culture with amniotic epithelial cells on the biological characteristics of amniotic mesenchymal stem cells

The aim of the present study was to investigate the effect of co‑culture with amniotic epithelial cells (AECs) on the biological characteristics of amniotic mesenchymal stem cells (AMSCs), to compare the expression of C‑X‑C motif chemokine receptor 4 (CXCR4) in co‑cultured AMSCs and to investigate the roles of the stromal cell‑derived factor‑1 (SDF‑1)/CXCR4 axis in the homing and migration of AMSCs. AMSCs were isolated from human amniotic membranes, purified and then differentiated into osteoblasts and adipocytes in vitro, which was verified by von Kossa Staining and Oil Red O staining. Cell viability was measured by Cell Counting kit‑8 and trypan blue assays at 24, 48 and 72 h, the expression of CXCR4 was analyzed by immunofluorescence‑based flow cytometry and reverse transcription‑quantitative polymerase chain reaction, and the migration ability of AMSCs in vitro was observed by a migration assay. The results demonstrated that cell viability (at 48 and 72 h) and survival (at 24, 48 and 72 h) in the co‑culture and serum groups were higher compared with the serum‑free group. Furthermore, CXCR4 mRNA and protein expression, and migration along the SDF‑1 gradient, in the co‑culture and serum‑free groups were higher compared with the serum group. Overall, the results indicated that AMSCs co‑cultured with AECs exhibited enhanced proliferation activity and survival rate. In conclusion, the present study demonstrated that co‑culture of AMSCs with AECs upregulated CXCR4 on the surface of AMSCs and enhanced the migration ability of AMSCs in vitro. This result may improve the directional migration and homing ability of AMSCs, as well as provide a theoretical basis for the application of AMSCs in clinical practice as a novel strategy to increase the success of hematopoietic stem cell transplantation.

miRNA-15a, miRNA-16, miRNA-126, miRNA-146a, and miRNA-223 expressions in autologous hematopoietic stem cell transplantation and their impact on engraftment

OBJECTIVE

MicroRNAs engaged in angiogenesis and hematopoiesis can influence hematopoietic stem cells (HSCs) homing after transplantation by targeting bone marrow niche microenvironment. This study aimed to examine the kinetics of miRNA-15a, miRNA-16, miRNA-126, miRNA-146a, and miRNA-223 in autologous HSC transplantation settings.

METHODS

The study comprised of 51 patients with hematological malignancies (42 multiple myeloma, 9 lymphoma). Samples were taken at four time points: before conditioning, after chemotherapy but prior to autologous HSC transplantation (day 0), on day +7, and +14 days after HSCT. The miRNA levels were evaluated by the real-time PCR method.

RESULTS

A significant, steady decline of all tested microRNAs in the course of transplantation, as compared to the baseline, was found. The study revealed that higher levels of miRNA-15a, miRNA-16, miRNA-126, and miRNA-146a on day 0 correlated with longer time to engraftment. Additionally, a positive correlation between the levels of miRNA-15a, miRNA-146a, and miRNA-223 assessed on day +7 and the time to engraftment was observed.

CONCLUSIONS

In conclusion, all investigated microRNAs changed significantly in the course of transplantation. Our results suggest that the miRNAs may participate in hematopoietic recovery in the early post-transplant period and influence engraftment efficiency after HSCT.