Therapy-related acute promyelocytic leukemia with FMS-like tyrosine kinase 3-internal tandem duplication mutation in solitary bone plasmacytoma: A case report

BACKGROUND Therapy-related acute promyelocytic leukemia(t-APL)is a rare complication observed in solitary bone plasmacytoma(SBP),and SBP after radiotherapy evolving to APL harboring the FMS-like tyrosine kinase 3-internal tandem duplication(FLT3-ITD)mutation has never been reported.Here,we present the first case reported until now.CASE SUMMARY We describe a 64-year-old woman who presented with lumbar pain and was initially diagnosed with SBP.However,after one year of radiotherapy treatment,this patient experienced a long-standing bone-marrow-suppressive period and finally developed APL harboring the FLT3-ITD mutation,as confirmed by analyses of clinical features,bone marrow morphology,flow cytometry,cytogenetic examination,and molecular biology.On admission,the patient had disseminated intravascular coagulation and intracranial hemorrhage,and the peripheral blood and bone marrow smear displayed abundant abnormal promyelocytes.Unfortunately,she died when the definite diagnosis was made.CONCLUSION The patient with t-APL harboring FLT3-ITD mutation evolving from SBP after radiotherapy had not been reported and had poor clinical outcomes.FLT3-ITD mutation in t-APL may be a potential pathogenesis of leukemogenesis.We should consider the potential risk of secondary neoplasms in SBP patients after radiotherapy.

Placenta Growth Factor and Soluble Fms-Like Tyrosine Kinase 1 in Preeclampsia and Normotensive Pregnant Nigerian Women

Background: Preeclampsia (PE) is still one of the leading causes of maternal/perinatal morbidity/mortality in Nigeria. Imbalance between placenta growth factor (PLGF) and soluble fms-like tyrosine kinase 1 (sFlt1) has been reportedly present both before and after the manifestation of PE;however, Nigerian data regarding these angiogenesis-related substances are lacking. We here attempted to determine the maternal serum level of PLGF and sFlt1 and sFlt1/PLGF ratio in PE vs. non-PE women in Lagos State University Teaching Hospital, Nigeria. Methods: An observational cross-sectional study was made on 75 women with PE and 75 age-gestational-age matched women without PE, as case and control, respectively. Levels of sFlt-1, PIGF and the sFlt-1: PIGF ratio was compared between the two. Results: Serum levels of Flt-1 and sFlt1/PIGF ratio were significantly higher in PE patients (6581.86 ± 865.75, and 146.42 ± 92.43) than in the normotensive control (4584.52 ± 1479.6 and 11.60 ± 6.42). PIGF was significantly lower in PE patients (70.14 ± 51.03) than the normotensives (494.06 ± 475.8). There were positive and negative correlations between the sFlt-1 and PLGF respectively and mean arterial blood pressure. Conclusion: Serum sFlt-1, sFlt1/PIGF ratio was significantly higher and PIGF levels were significantly lower in PE than normotensive control in Nigerian population.

A Recombinant Rabies Virus Expressing Fms-like Tyrosine Kinase 3 Ligand(Flt3L) Induces Enhanced Immunogenicity in Mice

Rabies is a zoonotic disease that still causes 59,000 human deaths each year,and rabies vaccine is the most effective way to control the disease.Our previous studies suggested that the maturation of DC plays an important role in enhancing the immunogenicity of rabies vaccine.Flt3L has been reported to own the ability to accelerate the DC maturation,therefore,in this study,a recombinant rabies virus expressing mouse Flt3L,designated as LBNSE-Flt3L,was constructed,and its immunogenicity was characterized.It was found that LBNSE-FU3L could enhance the maturation of DC both in vitro and in vivo,and significantly more TFH cells and Germinal Center B(GC B)cells were generated in mice immunized with LBNSE-FU3L than those immunized with the parent virus LBNSE.Consequently,expressing of Flt3L could elevate the level of virus-neutralizing antibodies(VNA)in immunized mice which provides a better protection from a lethal rabies virus challenge.Taken together,our study extends the potential of Flt3L as a good adjuvant to develop novel rabies vaccine by enhancing the VNA production through activating the DC—Tfh^GC B axis in immunized mice.

Maternal Vascular Dysfunction in Congenital Heart Defects

Background:Research on fetal congenital heart defect(CHD)mostly focuses on etiology and mechanisms.However,studies on maternal complications or pathophysiology are limited.Our objective was to determine whether vascular dysfunction exists in pregnant women carrying a fetus with congenital heart defects.Methods:We conducted a case-control study.27 cases of pregnant women carrying a fetus with major CHD admitted to our hospital for delivery between April 2021 and August 2022 were selected.Every case was matched with about 2 pregnant complication-free controls without fetal abnormalities.The proangiogenic and anti-angiogenic factors and pregnancy outcomes were compared.Results:The proangiogenic factors include vascular endothelial growth factor(VEGF)and placental growth factor(PlGF).The anti-angiogenic factors involve soluble fms-like tyrosine kinase 1(sFlt-1)and soluble endoglin(sEng).No differences were found in maternal plasma concentrations of PlGF,VEGF,and sFlt-1 between case-control groups when analyzed at 36 weeks≤gestational age(GA)<39 weeks and 39 weeks≤GA≤41 weeks.The concentrations of sEng in maternal plasma in the fetal CHD group were significantly higher than those in the control group:0.60(0.77)vs.0.32(0.26)ng/ml at 36 weeks≤GA<39 weeks,p=0.001 and 0.75(0.55)vs.0.28(0.27)ng/ml at 39 weeks≤GA≤41 weeks,p<0.001.Conclusion:Vascular dysfunction exists in pregnant women with fetal congenital heart defects,manifesting significantly elevated sEng concentration at delivery.

Blocking effects of siRNA on VEGF expression in human colorectal cancer cells

AIM:To investigate the expression of vascular endothelial cell growth factor (VEGF) and its receptors Fmslike tyrosine kinase 1 (FLT-1) and fetal liver kinase 1 (FLK-1) in colorectal carcinoma (CRC),and the blocking effects of small interfering RNAs (siRNAs) on VEGF expression in human colorectal cancer HCT116 cells.METHODS:Immunohistochemical staining for VEGF,FLT-1 and FLK-1 proteins was performed in 82 cases of CRC and 14 normal colorectal mucosae.A siRNA targeting VEGF was synthesized and transfected into HCT116 cells using lipofectamine 2000.Immunocytochemical staining and Western blotting analyses were performed to detect the expression of VEGF protein.The suppressive effect of the siRNA on cell proliferation was detected using the 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyltertrazolium bromide (MTT) assay.Cellular apoptosis was detected using flow cytometry (FCM).RESULTS:The expression of VEGF,FLT-1 and FLK-1 in tumor tissues was significantly higher than that in normal tissues (P=0.008,P=0.000,P=0.000).The expression of VEGF was positively correlated with both lymph node metastasis and clinical stage (P=0.009 and P=0.025,respectively).Immunocytochemistry showed that the expression of VEGF was weakly positive and Western blotting indicated a significant reduction in VEGF-siRNA cell protein levels.VEGF-siRNA cell growth inhibition was assessed by the MTT assay,and the tumor cell proliferation rate was significantly different at 24,48,and 72 h after transfection.FCM results showed that the VEGF-siRNA group had an apparent aneuploid peak.CONCLUSION:VEGF,FLT-1 and FLK-1 are associated with colorectal carcinogenesis.siRNA silencing of the VEGF gene suppresses proliferation,and induces apoptosis in HCT116 cells.The results suggest that VEGF may be a new gene therapy target for colorectal cancer.

Effect of Bushen Yiqi Huoxue Recipe on Placental Vasculature in Pregnant Rats with Fetal Growth Restriction Induced by Passive Smoking

Interactions of vascular endothelial growth factor （VEGF） with receptors VEGFR1/Fltl and VEGFR2/Flk1, and those of angiopoietins （Ang-1, Ang-2） with receptor Tie2 play important roles in placental angiogenesis. This study investigated vascular morphology and expression of these angiogenic factors in rat placenta on the day 15, 18, 21 of gestation （D 15, D 18 and D21）. The rats were randomly assigned into 3 groups： normal group, model group [fetal growth restriction （FGR） model], and Bushen Tqi Huoxue （BYHR） recipe treatment group （BYHR group, the pregnant rats with FGR were treated with BYHR recipe）. Morphological analysis indicated that during initial villous formation, fetal nucle- ated erythrocytes （FNEs） appeared in maternal blood sinus （MBS）. Subsequently, FNEs were sur- rounded by endothelial cells to form fetal capillary （FC） and then by trophoblast cells to form villi. As pregnancy proceeded, FC density increased progressively with increasing endothelial identification staining （EIS） in normal and BYHR groups. Whereas, villous formation was suppressed, normal in- crease in FC density was impaired and EIS was weakened in model group. Quantitative PCR analysis showed that VEGF and Flkl mRNA increased over gestation in all groups, indicating that VEGF might play a pivotal role in FC growth during late gestation. VEGF mRNA was increased on D15, while de- creased on D21 in model group as compared with normal group and BYHR group. Immunohistochemi- cally, Ang-2 protein was highly expressed in FNEs, gradually disappeared as villi matured, and decreased over gestation in all groups, indicating that Ang-2 might play a pivotal role in villous formation, which was further supported by decreased Ang-2 mRNA and protein expression in model group on D 15. Ang-1 mRNA, Tie2 mRNA and Ang-1/Ang-2 ratio increased from D15 to D18 in all groups as placenta matured. Ang-1 mRNA, Tie2 mRNA and Ang-1/Ang-2 ratio were decreased on D18 in model group as compared with normal and BYHR groups, indicating delayed maturity of FGR placenta. Alterations in angiogenic factors may result in altered placental vasculature and cause placental insufficiency. BYHR recipe could balance the angiogenic factors to promote the formation and maturation of FGR placental vasculature.

A novel recombinant DNA vaccine encodingMycobacterium tuberculosis ESAT-6 and FL protects againstMycobacterium tuberculosis challenge in mice

Mycobacterium tuberculosis 6-kDa early secretory antigenic target （ESAT-6） is a dominant target antigen for cell-mediated immunity in the early phase of tuberculosis. The fms-like tyrosine kinase 3 ligand （FL） that induces potent immune response has been used as an adjuvant in vaccine development. In this study, a new recombinant plasmid （plRES-epitope-peptides-FL） encoding three T cell epitopes of ESAT-6 and FL was constructed, and the immunogenicity of the DNA vaccine was assessed in C57BL/6 mice immunized with the plasmid DNA vaccine. Additionally, a strategy of intramuscular injection with the DNA vaccine （prime） and intranasal administration of the epitope peptides （boost） was employed to induce higher immune reaction of the mice. The results showed that mice vaccinated with the recombinant plasmid DNA vaccine and boosted with the peptides not only increased the levels of Thl cytokines （IFN-γ and IL-12）, the number of IFN-γ＋ T cells and activities of cytotoxic T lymphocytes as well as IgG, but also enhanced protection against Mycobacterium tuberculosis challenge. In conclusion, these data indicate that the novel recombinant plRES-epitope-peptides-FL plasmid is a useful DNA vaccine for pre- venting Mycobacterium tuberculosis infection.

三种PML/RARA亚型急性早幼粒细胞白血病临床特点对比分析

目的：分析并比较不同早幼粒细胞白血病／维甲酸受体α融合基因（ PML／RARA）亚型急性早幼粒细胞白血病（ APL）的临床特点。方法收集我中心2010～2014年108例初诊APL患者的临床资料，分析不同PML／RARA亚型的特点。结果最常见的PML／RARA亚型为L型（67例，62．0％），其次为S型（30例，27．8％）、V型（11例，10．2％）。 V型患者合并出血的比例（45．5％）低于L型（74．6％）和S型（86．7％），P均＜0．05；V型患者中位纤维蛋白原水平（1．98 g／L）高于L型（1．18 g／L）和S型（1．05 g／L），P均＜0．05。 S型患者（26．7％）较L型（7．6％）和V型（0）更易伴发FMS样酪氨酸酶3内部串联重复（FLT3／ITD）突变，P均＜0．05。 S型患者CD34表达阳性率（24．1％）高于L型（6．3％）和V型（11．1％），P均＜0．05。高、中、低危组维甲酸综合征发生率分别为56．3％、28．8％、17．5％（ P均＜0．05）。三种PML／RARA亚型维甲酸综合征的发生率差异无统计学意义。结论三种PML／RARA亚型的APL临床特点不尽相同，L型最常见，V型出血发生率较低，S型较易伴FLT3／ITD突变和CD34阳性表达。

All-trans Retinoic Acid,Arsenic Trioxide,and Anthracycline-based Chemotherapy Improves Outcome in Newly Diagnosed Acute Promyelocytic Leukemia Regardless of FLT3-ITD Mutation Status

All-trans retinoic acid(ATRA)and pre-upfront arsenic trioxide(ATO)have revolutionized the therapy of acute promyelocytic leukemia(APL).However,internal tandem duplication of FMS-like tyrosine kinase 3(FLT3-ITD)mutations is associated with increased risk of relapse.The aim of this study was to analyze the prognostic impact of FLT3-ITD on APL patients who received remission induction with ATRA,idarubicin(IDA)and/or ATO,followed by ATRA plus ATO along with anthracycline,as consolidation therapy.A total of 72 patients newly diagnosed with APL were included in this study.83.3%of the patients achieved complete remission(CR)after induction therapy.FLT3-ITD mutations were detected in 16(22.2%)patients and closely related to bcr-3 PML-RARa transcript(P<0.001).The 5-year overall survival(OS)rate was 100%in both FLT3-ITDposltlve and FLT3-ITD^(negatlve)groups,and there was no significant difference in 5-year event-free survival(EFS)between the two groups(78.3%vs.83.3%,P=0.85).ATRA plus ATO and anthracycline-based chemotherapy achieved great outcome in newly diagnosed APL regardless of the FLT3-ITD mutation status.

Resistance to FLT3 inhibitors in acute myeloid leukemia: Molecular mechanisms and resensitizing strategies

FMS-like tyrosine kinase 3(FLT3) is classified as a type Ⅲ receptor tyrosine kinase, which exerts a key role in regulation of normal hematopoiesis. FLT3 mutation is the most common genetic mutation in acute myeloid leukemia(AML) and represents an attractive therapeutic target. Targeted therapy with FLT3 inhibitors in AML shows modest promising results in current ongoing clinical trials suggesting the complexity of FLT3 targeting in therapeutics. Importantly, resistance to FLT3 inhibitors may explain the lack of overwhelming response and could obstruct the successful treatment for AML. Here, we summarize the molecular mechanisms of primary resistance and acquired resistance to FLT3 inhibitors and discuss the strategies to circumvent the emergency of drug resistance and to develop novel treatment intervention.

Antibiotic and glucocorticoid-induced recapitulated hematological remission in acute myeloid leukemia:A case report and review of literature

BACKGROUND Leukemic hematopoietic cells acquire enhanced self-renewal capacity and impaired differentiation.The emergence of symptomatic leukemia also requires the acquisition of a clonal proliferative advantage.Untreated leukemia patients usually experience an aggressive process.However,spontaneous remission occasionally occurs in patients with acute myeloid leukemia(AML),most frequently after recovery from a febrile episode,and this is generally attributed to the triggering of antineoplastic immunity.There may be another explanation for the spontaneous remission as implicated in this paper.CASE SUMMARY A 63-year-old Chinese man presented with high fever,abdominal pain and urticaria-like skin lesions.He was diagnosed with AML-M4 with t(8;21)(q22;q22)/RUNX1-RUNX1T1 based on morphological,immunological,cytogenetic and molecular analyses.He had a complex chromosome rearrangement of 48,XY,t(8;21)(q22;q22),+13,+13[9]/49,idem,+mar[9]/49,idem,+8[2].He also had a mutated tyrosine kinase domain in fms-like tyrosine kinase 3 gene.He was treated with antibiotics and glucocorticoids for gastrointestinal infection and urticaria-like skin lesions.The infection and skin lesions were quickly resolved.Unexpectedly,he achieved hematological remission along with resolution of the febrile episode,gastrointestinal symptoms and skin lesions.Notably,after relapse,repeating these treatments resulted in a return to hematological remission.Unfortunately,he demonstrated strong resistance to antibiotic and glucocorticoid treatment after the second relapse and died of sepsis from bacterial infection with multidrug resistance.The main clinical feature of this patient was that symptomatic AML emerged with flaring of the gut inflammatory disorder and it subsided after resolution of the inflammation.Learning from the present case raises the possibility that in a subgroup of AML patients,the proliferative advantage of leukemia cells may critically require the presence of inflammatory stresses.CONCLUSION Inflammatory stresses,most likely arising from gastrointestinal infection,may sustain the growth and survival advantage of leukemic cells.

The equivalents of human blood and spleen dendritic cell subtypes can be generated in vitro from human CD34 ＋ stem cells in the presence of fins-like tyrosine kinase 3 ligand and thrombopoietin

Dendritic cells （DCs） are immune cells specialized to capture, process and present antigen to T cells in order to initiate an appropriate adaptive immune response. The study of mouse DC has revealed a heterogeneous population of cells that differ in their development, surface phenotype and function. The study of human blood and spleen has shown the presence of two subsets of conventional DC including the CDlb/c＋ and CD141＋CLEC9A＋ conventional DC （cDC） and a plasmacytoid DC （pDC） that is CD304＋CD123＋. Studies on these subpopulations have revealed phenotypic and functional differences that are similar to those described in the mouse. In this study, the three DC subsets have been generated in vitrofrom human CD34＋ precursors in the presence of fins-like tyrosine kinase 3 ligand （FIt3L） and thrombopoietin （TPO）. The DC subsets so generated, including the CDlb/c＋ and CLEC9A＋ cDCs and CD123 ＋ pDCs, were largely similar to their blood and spleen counterparts with respect to surface phenotype, toll-like receptor and transcription factor expression, capacity to stimulate T cells, cytokine secretion and cross-presentation of antigens. This system may be utilized to study aspects of DC development and function not possible in vivo.