Yangqiu Li

The role of PD-1 and PD-L1 in T-cell immune suppression in patients with hematological malignancies.

T-cell activation and dysfunction relies on direct and modulated receptors. Based on their functional outcome, co-signaling molecules can be divided as co-stimulators and co-inhibitors, which positively and negatively control the priming, growth, differentiation and functional maturation of a T-cell response. We are beginning to understand the power of co-inhibitors in the context of lymphocyte homeostasis and the pathogenesis of leukemia, which involves several newly described co-inhibitory pathways, including the programmed death-1 (PD-1) and PD-1 ligand (PD-L1) pathway. The aim of this review is to summarize the PD-1 and PD-L1 biological functions and their alterative expression in hematological malignancies. The role of PD-1 and PD-L1 in T-cell immune suppression and the potential for immunotherapy via blocking PD-1 and PD-L1 in hematological malignancies are also reviewed.

Inhibition of long non-coding RNA NEAT1 impairs myeloid differentiation in acute promyelocytic leukemia cells

BackgroundAcute promyelocytic leukemia (APL) is characterized by the reciprocal translocation t(15;17), which fuses PML with retinoic acid receptor alpha (RARα). Although PML-RARα is crucially important for pathogenesis and responsiveness to treatment, the molecular and cellular mechanisms by which PML-RARα exerts its oncogenic potential have not been fully elucidated. Recent reports have suggested that long non-coding RNAs (lncRNAs) contribute to the precise control of gene expression and are involved in human diseases. Little is known about the role of lncRNA in APL.MethodsWe analyzed NEAT1 expression in APL samples and cell lines by real-time quantitative reverse transcription-PCR (qRT-PCR). The expression of PML-RARα was measured by Western blot. Cell differentiation was assessed by measuring the surface CD11b antigen expression by flow cytometry analysis.ResultsWe found that nuclear enriched abundant transcript 1 (NEAT1), a lncRNA essential for the formation of nuclear body paraspeckles, is significantly repressed in de novo APL samples compared with those of healthy donors. We further provide evidence that NEAT1 expression was repressed by PML-RARα. Furthermore, significant NEAT1 upregulation was observed during all-trans retinoic acid (ATRA)-induced NB4 cell differentiation. Finally, we demonstrate the importance of NEAT1 in myeloid differentiation. We show that reduction of NEAT1 by small interfering RNA (siRNA) blocks ATRA-induced differentiation.ConclusionsOur results indicate that reduced expression of the nuclear long noncoding RNA NEAT1 may play a role in the myeloid differentiation of APL cells.

Immunomodulation Effects of Mesenchymal Stromal Cells on Acute Graft-versus-Host Disease after Hematopoietic Stem Cell Transplantation

Refractory acute graft-versus-host disease (aGVHD) is a major cause of death after allogeneic hematopoietic stem cell transplantation. This study evaluated the immunomodulation effects of mesenchymal stromal cells (MSCs) from bone marrow of a third-party donor for refractory aGVHD. Forty-seven patients with refractory aGVHD were enrolled: 28 patients receiving MSC and 19 patients without MSC treatment. MSCs were given at a median dose of 1 × 10(6) cells/kg weekly until patients got complete response or received 8 doses of MSCs. After 125 doses of MSCs were administered, with a median of 4 doses (range, 2 to 8) per patient, overall response rate was 75% in the MSC group compared with 42.1% in the non-MSC group (P = .023). The incidence of cytomegalovirus, Epstein-Barr virus infections, and tumor relapse was not different between the 2 groups during aGVHD treatment and follow-up. The incidence and severity of chronic GVHD in the MSC group were lower than those in the non-MSC group (P = .045 and P = .005). The ratio of CD3(+)CD4(+)/CD3(+)CD8(+) T cells, the frequencies of CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs), and the levels of signal joint T cell-receptor excision DNA circles (sjTRECs) after MSCs treatment were higher than those pretreatment. MSC-treated patients exhibited higher Tregs frequencies and sjTRECs levels than those in the non-MSC group at 8 and 12 weeks after treatment. MSCs derived from bone marrow of a third-party donor are effective to refractory aGVHD. It might reduce the incidence and severity of chronic GVHD in aGVHD patients by improving thymic function and induction of Tregs but not increase the risks of infections and tumor relapse.

Overexpression of the long non-coding RNA PVT1 is correlated with leukemic cell proliferation in acute promyelocytic leukemia

BackgroundAcute promyelocytic leukemia (APL) is associated with chromosomal translocation t(15;17), which results in the proliferation of morphologically abnormal promyelocytes. Gain of supernumerary copies of the 8q24 chromosomal region, which harbors MYC and PVT1, has been shown to be the most common secondary alteration in human APL. Increased MYC can accelerate the development of myeloid leukemia in APL. However, the role that the expression of the long non-coding RNA (lncRNA) PVT1 plays in the pathogenesis of APL remains largely unknown.FindingsIn this study, we first analyzed the lncRNA PVT1 expression level in peripheral blood cells from 28 patients with de novo APL, and significantly upregulated PVT1 was found in APL patients compared with healthy donors. We then observed significantly lower MYC and PVT1 expression during all-trans retinoic acid (ATRA)-induced differentiation and cell cycle arrest in the APL cell line. MYC knockdown in NB4 cells led to PVT1 downregulation. Moreover, PVT1 knockdown by RNA interference led to suppression of the MYC protein level, and cell proliferation was inhibited.ConclusionOur findings reveal that the lncRNA PVT1 may play an important role in the proliferation of APL cells and may be useful for future therapeutic management.

Mutations increased overexpression of Notch

BackgroundThe Notch signaling pathway is crucial in T-cell development, Notch 1 mutations are frequently present in T-cell acute lymphoblastic leukemia (T-ALL). To investigate the feature of Notch 1 mutation and its corresponding expression level in Chinese patients with T-ALL, detection of mutation and the expression level of Notch 1 gene was preformed using RT-PCR, sequencing and real-time PCR respectively.ResultsTwo Notch 1 point mutations (V1578E and L1593P) located on HD-N domain were identified in three cases out of 13 T-ALL patients. The mutation on 4733 position (V1578E) found in two cases was a novel mutation. The overexpression of Notch 1 was detected in all samples with T-ALL, moreover, significantly higher expression of Notch 1 was detected in the T-ALL with Notch 1 mutation group compared with T-ALL with WT Notch 1 group (p = 0.0192).ConclusionsHigher expression of Notch 1 was associated with Notch 1 mutation, more novel mutation of this gene might be identified in different populations and its contribution to the molecular pathogenesis of T-ALL is needed further research.

Altered expression pattern of miR-29a, miR-29b and the target genes in myeloid leukemia

ObjectivesThe miR-29 family have been demonstrated acting as vital tumor suppressor in multiple cancers as well as regulators in the adaptive immune system. Little is known about their role in leukemogenesis. The purpose of this study is to analyze the expression pattern of miR-29a/29b and its target genes Mcl-1 (myeloid cell leukemia sequence 1) and B-cell lymphoma 2 (Bcl-2) in myeloid leukemia.MethodsQuantitative real-time PCR was used for detecting genes expression level in peripheral blood mononuclear cells (PBMCs) from 10 cases with newly diagnosed, untreated acute myeloid leukemia (AML) and 14 cases with newly diagnosed, untreated chronic myeloid leukemia (CML) in chronic phase, and 14 healthy individual (HI) served as controls. Correlation between the relative expression levels of different genes have been analyzed.ResultsSignificant lower expression of miR-29a/29b and higher expression level of two potential target genes Bcl-2 and Mcl-1 were found in PBMCs from AML and CML patients compared with HI group. In addtion, miR-29a expression in AML was significantly lower than that in CML. Moreover, negative correlation between miR-29a/29b and its target genes have been found. While, positive correlation between relative expression level of miR-29a and miR-29b or Bcl-2 and Mcl-1 were presented in the total 38 research objects.ConclusionDown-regulated miR-29a and miR-29b, and accompanying up-regulated Bcl-2 and Mcl-1 are the common feature in myeloid leukemias. These data further support the role for miR-29a/29b dysregulation in myeloid leukemogenesis and the therapeutic promise of regulating miR-29a/29b expression for myeloid leukemia in the future.

The role of BCL11B in hematological malignancy

The B-cell leukemia/lymphoma 11B (BCL11B) gene is a member of the BCL family which plays a crucial role in the development, proliferation, differentiation and subsequent survival of T cells. BCL11B gene alterations are related to malignant T cell transformation that occurs in hematological malignancies. Remarkably, the BCL11B gene is responsible for the regulation of the apoptotic process and cell proliferation. This review summarizes current data and knowledge concerning the alteration of BCL11B in hematological malignancies and its role as a potential target for therapies directed against T cell malignancies.

HoxBlinc RNA recruits Set1/MLL complexes to activate Hox gene expression patterns and mesoderm lineage development

Trithorax proteins and long-intergenic noncoding RNAs are critical regulators of embryonic stem cell pluripotency; however, how they cooperatively regulate germ layer mesoderm specification remains elusive. We report here that HoxBlinc RNA first specifies Flk1(+) mesoderm and then promotes hematopoietic differentiation through regulation of hoxb pathways. HoxBlinc binds to the hoxb genes, recruits Setd1a/MLL1 complexes, and mediates long-range chromatin interactions to activate transcription of the hoxb genes. Depletion of HoxBlinc by shRNA-mediated knockdown or CRISPR-Cas9-mediated genetic deletion inhibits expression of hoxb genes and other factors regulating cardiac/hematopoietic differentiation. Reduced hoxb expression is accompanied by decreased recruitment of Set1/MLL1 and H3K4me3 modification, as well as by reduced chromatin loop formation. Re-expression of hoxb2-b4 genes in HoxBlinc-depleted embryoid bodies rescues Flk1(+) precursors that undergo hematopoietic differentiation. Thus, HoxBlinc plays an important role in controlling hoxb transcription networks that mediate specification of mesoderm-derived Flk1(+) precursors and differentiation of Flk1(+) cells into hematopoietic lineages.

Analysis of the expression pattern of the BCL11B gene and its relatives in patients with T-cell acute lymphoblastic leukemia

BackgroundIn a human T-cell acute lymphoblastic leukemia (T-ALL) cell line (Molt-4), siRNA-mediated suppression of BCL11B expression was shown to inhibit proliferation and induce apoptosis, functions which may be related to genes involved in apoptosis (such as TNFSF10 and BCL2L1) and TGF-β pathways (such as SPP1 and CREBBP).MethodsThe expression levels of the above mentioned genes and their correlation with the BCL11B gene were analyzed in patients with T-ALL using the TaqMan and SYBR Green I real-time polymerase chain reaction technique.ResultsExpression levels of BCL11B, BCL2L1, and CREBBP mRNA in T-ALL patients were significantly higher than those from healthy controls (P < 0.05). In T-ALL patients, the BCL11B expression level was negatively correlated with the BCL2L1 expression level (rs = -0.700; P< 0.05), and positively correlated with the SPP1 expression level (rs = 0.683; P< 0.05). In healthy controls, the BCL11B expression level did not correlate with the TNFSF10, BCL2L1, SPP1, or CREBBP expression levels.ConclusionsOver-expression of BCL11B might play a role in anti-apoptosis in T-ALL cells through up-regulation of its downstream genes BCL2L1 and CREBBP.

Clonal expanded TCR Vbeta T cells in patients with APL.

T-cell receptor Vss gene repertoire and clonality have been studied in patients with leukemia and solid tumors, by assaying the CDR3 size of TCR genes, using RT-PCR and genescan analysis. Few studies have studied leukemia-associated oligoclonal expanded T-cells in leukemia, therefore, the aim of this study was to investigate the distribution and clonal expansion of T-cell receptor, Vss subfamily T-cells in patients with acute promyelocytic leukemia (APL) with t(15;17). The CDR3 of TCR Vbeta24 subfamily genes were analyzed in peripheral blood mononuclear cells from 17 cases with PML-RARalpha+ APL using RT-PCR and genescan technique. Ten normal individuals served as controls. The results showed that the number of expressed Vss subfamilies (from 2 to 21 subfamilies) varied in different patients with APL. The most frequently expressed Vss subfamilies were Vbeta2 (64.7%), Vbeta15 (58.8%), Vbeta3 and Vbeta5 (47.1%), with a lower expression rate found in Vbeta11 and Vbeta20 (11.7%). Clonally expanded T-cells in the Vss subfamilies could be identified in patients with APL in all but two of the cases studied, predominantly in Vbeta10, Vbeta23, Vbeta3 and Vbeta21. In conclusion, skewed distribution and clonal expansion of TCR Vss subfamily T-cells could be found in patients with APL. The clonal expansion of T-cells were considered to be a specific anti-leukemic immune response by host T-cells activated by the leukemia-associated-antigen.