Genetic characteristics and survival analysis of 27 cases of juvenile myelomonocytic leukemia / 中华儿科杂志

Objective: To investigate the genetic and genomic profiling of juvenile myelomonocytic leukemia (JMML) and factors affecting its survival rate. Methods: Clinical characteristics, cytogenetics, molecular biology results and survival status of children with 27 JMML cases admitted to the Hematology Department of Children's Hospital, Capital Institute of Pediatrics from December 2012 to December 2021 were analyzed retrospectively, and the outcomes of the children were followed up. Kaplan-Meier method was used for survival analysis. Univariate analysis was used for analyzing factors affecting the overall survival (OS) rates of patients who received hematopoietic stem cell transplantation (HSCT). Log-Rank test was used for comparison of survival curves. Results: Among 27 JMML cases, there were 11 males and 16 females. The age of disease onset was 28 (11,52) months. There are 20 cases of normal karyotype, 4 cases of monosomy 7, 1 case of trisomy 8,1 case of 11q23 rearrangement and 1 case of complex karyotype. A total of 39 somatic mutations were detected.Those involved in RAS signal pathway were the highest (64%(25/39)), among which PTPN11 mutation was the most frequent (44% (11/25)). A total of 17 cases (63%) received HSCT, 8 cases (30%) did not receive HSCT, and 2 cases (7%) lost follow-up. For children receiving transplantation, the follow-up time after transplantation was 47 (11,57) months. The 1-year OS rate of high-risk transplantation group (17 cases) and high-risk non transplantation group (6 cases) was (88±8)% and (50±20)% respectively, with a statistically significant difference (χ2=5.01, P=0.025). The 5-year OS rate of the high-risk transplantation group was (75±11)%. The survival time of those who relapsed or progressed to acute myeloid leukemia after transplantation was significantly shorter than that of those who did not relapse (χ2=6.80, P=0.009). The OS rate of patients with or without PTPN11 mutation was (81±12) % and (67±19)% respectively (χ2=0.85, P=0.356). Conclusions: The main pathogenesis involved in JMML is gene mutation related to RAS signaling pathway, and the most common driver gene of mutation is PTPN11. Allogeneic HSCT can significantly improve the survival rate of high-risk JMML patients. The recurrence or progression after transplantation was related to poor prognosis.

The Viral Load of Epstein-Barr Virus in Blood of Children after Hematopoietic Stem Cell Transplantation.

Objective: To detect the Epstein-Barr virus (EBV) viral load of children after hematopoietic stem cell transplantation (HSCT) using chip digital PCR (cdPCR). Methods: The sensitivity of cdPCR was determined using EBV plasmids and the EBV B95-8 strain. The specificity of EBV cdPCR was evaluated using the EBV B95-8 strain and other herpesviruses (herpes simplex virus 1, herpes simplex virus 2, varicella zoster virus, human cytomegalovirus, human herpesvirus 6, and human herpesvirus 7). From May 2019 to September 2020, 64 serum samples of children following HSCT were collected. EBV infection and the viral load of serum samples were detected by cdPCR. The epidemiological characteristics of EBV infections were analyzed in HSCT patients. Results: The limit of detection of EBV cdPCR was 110 copies/mL, and the limit of detection of EBV quantitative PCR was 327 copies/mL for the pUC57-BALF5 plasmid. The result of EBV cdPCR was up to 121 copies/mL in the EBV B95-8 strain, and both were more sensitive than that of quantitative PCR. Using cdPCR, the incidence of EBV infection was 18.75% in 64 children after HSCT. The minimum EBV viral load was 140 copies/mL, and the maximum viral load was 3,209 copies/mL using cdPCR. The average hospital stay of children with EBV infection (184 ± 91 days) was longer than that of children without EBV infection (125 ± 79 days), P = 0.026. Conclusion: EBV cdPCR had good sensitivity and specificity. The incidence of EBV infection was 18.75% in 64 children after HSCT from May 2019 to September 2020. EBV cdPCR could therefore be a novel method to detect EBV viral load in children after HSCT.

Clinical outcomes of individualized busulfan-dosing in hematopoietic stem cell transplantation in Chinese children undergoing with therapeutic drug monitoring.

To identify relationships between busulfan (Bu) exposure and outcomes of a cohort pediatric patients receiving hematopoietic stem cell transplantation (HSCT), along with a targeted busulfan-based conditioning regimen. We retrospectively evaluated targeted busulfan concentrations in 53 pediatric patients (age 0.4-16 years) who received busulfan 4 times daily according to recommended weight-based doses in a single-center analysis between 2018 and 2020. In this trial, individual busulfan pharmacokinetics were performed following dose 5 of the conditioning regimen. Twenty four of 53 patients (45.3%) studies did not require dose adjustments. Equal number of patients (24/53) required one dose adjustments while two-dose adjustment applied for 5 of 53 (9.4%). Twenty-one percent of the patients exhibited ll-lV aGVHD. The incidence of veno-occlusive disease (VOD) was in 3.8% of the 53 patients, while incidence of hemorrhagic cystitis (II-III) reached to 9.7%. Engraftment was successful in 98% of the 53 patients with relapse in 2% of cases. The probability of overall survival and disease-free survival at day 100 was 96% and 94%, respectively. In conclusion, therapeutic drug monitoring (TDM) and individualization of Bu dosage are essential to improve the efficacy and safety of busulfan-based regimen in Chinese pediatric HSCT recipients.

The ARF2-ANT-COR15A gene cascade regulates ABA-signaling-mediated resistance of large seeds to drought in Arabidopsis.

Seedlings of large-seeded plants are considered to be able to withstand abiotic stresses efficiently. The molecular mechanisms that underlie the involved signaling crosstalk between the large-seeded trait and abiotic tolerance are, however, largely unknown. Here, we demonstrate the molecular link that integrates plant abscisic acid (ABA) responses to drought stress into the regulation of seed mass. Both loss-of-function mutants of the Auxin Response Factor 2 (ARF2 encoding a transcription factor) and lines overexpressing AINTEGUMENTA (ANT; a transcription factor) under the 35S promoter exhibited large seed and drought-tolerant phenotypes as a result of abnormal ABA-auxin crosstalk signaling pathways in Arabidopsis. The target gene COLD-REGULATED15A (COR15a) was identified as participating in the regulation of seed development with ABA signaling through a negative regulation mechanism that is mediated by ANT. The molecular and genetic evidence presented indicate that ARF2, ANT and COR15A form an ABA-mediated signaling pathway to link modulation of seed mass with drought tolerance. These observations indicate that the ARF2 transcription factor serves as a molecular link that integrates plant ABA responses to drought stress into the regulation of seed mass.

Arabidopsis AINTEGUMENTA mediates salt tolerance by trans-repressing SCABP8.

The Arabidopsis AINTEGUMENTA (ANT) gene, which encodes an APETALA2 (AP2)-like transcription factor, controls plant organ cell number and organ size throughout shoot development. ANT is thus a key factor in the development of plant shoots. Here, we have found that ANT plays an essential role in conferring salt tolerance in Arabidopsis. ant-knockout mutants presented a salt-tolerant phenotype, whereas transgenic plants expressing ANT under the 35S promoter (35S:ANT) exhibited more sensitive phenotypes under high salt stress. Further analysis indicated that ANT functions mainly in the shoot response to salt toxicity. Target gene analysis revealed that ANT bound to the promoter of SOS3-LIKE CALCIUM BINDING PROTEIN 8 (SCABP8), which encodes a putative Ca(2+) sensor, thereby inhibiting expression of SCABP8 (also known as CBL10). It has been reported that the salt sensitivity of scabp8 is more prominent in shoot tissues. Genetic experiments indicated that the mutation of SCABP8 suppresses the ant-knockout salt-tolerant phenotype, implying that ANT functions as a negative transcriptional regulator of SCABP8 upon salt stress. Taken together, the above results reveal that ANT is a novel regulator of salt stress and that ANT binds to the SCABP8 promoter, mediating salt tolerance.

Transcription co-activator Arabidopsis ANGUSTIFOLIA3 (AN3) regulates water-use efficiency and drought tolerance by modulating stomatal density and improving root architecture by the transrepression of YODA (YDA).

One goal of modern agriculture is the improvement of plant drought tolerance and water-use efficiency (WUE). Although stomatal density has been linked to WUE, the causal molecular mechanisms and engineered alternations of this relationship are not yet fully understood. Moreover, YODA (YDA), which is a MAPKK kinase gene, negatively regulates stomatal development. BR-INSENSITIVE 2 interacts with phosphorylates and inhibits YDA. However, whether YDA is modulated in the transcriptional level is still unclear. Plants lacking ANGUSTIFOLIA3 (AN3) activity have high drought stress tolerance because of low stomatal densities and improved root architecture. Such plants also exhibit enhanced WUE through declining transpiration without a demonstrable reduction in biomass accumulation. AN3 negatively regulated YDA expression at the transcriptional level by target-gene analysis. Chromatin immunoprecipitation analysis indicated that AN3 was associated with a region of the YDA promoter in vivo. YDA mutation significantly decreased the stomatal density and root length of an3 mutant, thus proving the participation of YDA in an3 drought tolerance and WUE enhancement. These components form an AN3-YDA complex, which allows the integration of water deficit stress signalling into the production or spacing of stomata and cell proliferation, thus leading to drought tolerance and enhanced WUE.

Nilotinib treatment for patients with imatinib-resistant or intolerant chronic myeloid leukemia / 中国实验血液学杂志

This study was purposed to evaluate the efficacy and safety of nilotinib for treating patients with imatinib-resistant or intolerant chronic myeloid leukemia (CML). A total of 23 patients with imatinib-resistant or intolerant CML were enrolled in this study. These patients received nilotinib orally 600-800 mg every day, their curative efficacy, tolerance and overal survival were evaluated. The results showed that all the patients treated with nilotinib obtained complete hematologic remission (CHR), out of them 82.6% patients achieved complete cytogenetic remission (CCyR) and 56.5% patients achieved complete molecular remission (CMR), their adverse events mostly were mild to moderate, generally were transient and easily cured; the median treatment time with nilotinib was 13.5 (1-44) months, and the median follow-up time was 40 (12-102) months. It is concluded that nilotinib has been confirmed to be effective for patients with imatinib-resistant or intolerant CML, and may be selected as a second generation of tyrosine kinase inhibitor (TKI).

[Suppression of survivin gene in leukemia cells by small interfering RNA].

OBJECTIVE: To evaluate the impact of specific siRNA on survivin gene in transfected leukemia cells. METHOD: The small interfering RNA (siRNA) targeted survivin mRNA was synthesized in vitro and was transfected into K562 cell by Hiperfect into human leukemia cell line K562, which has high survivin expression level. The level of survivin mRNA expression was determined by quantitative reverse transcription polymerase chain reaction (RT-PCR) with SYBR GREEN I. The apoptosis index of cytotrophoblasts were determined and analyzed by FCM (Annexin V-FITC/PI staining methods). The cell proliferation was examined by MTT at 48 h and 72 h after transfection. RESULT: The level of mRNA expression was significantly inhibited by the siRNA 48 h and 72 h after transfection, the suppression rate of survivin mRNA separately reached 85.21%, 94.35% mensurated by quantitative RT-PCR with SYBR GREEN I, cell proliferation was inhibited significantly by 45.02% and 50.88%, respectively, the apoptotic rate detected by Annexin V-FITC assay reached 12.28%and 21.55%, respectively. CONCLUSION: The chemosynthesized siRNA targeting survivin could significantly down-regulate survivin mRNA. Survivin siRNA was able to inhibit the proliferation of leukemia cell line K562. Survivin may become a new target for leukemia gene therapy.

Suppression of survivin gene in leukemia cells by small interfering RNA / 中华儿科杂志

<p><b>OBJECTIVE</b>To evaluate the impact of specific siRNA on survivin gene in transfected leukemia cells.</p><p><b>METHOD</b>The small interfering RNA (siRNA) targeted survivin mRNA was synthesized in vitro and was transfected into K562 cell by Hiperfect into human leukemia cell line K562, which has high survivin expression level. The level of survivin mRNA expression was determined by quantitative reverse transcription polymerase chain reaction (RT-PCR) with SYBR GREEN I. The apoptosis index of cytotrophoblasts were determined and analyzed by FCM (Annexin V-FITC/PI staining methods). The cell proliferation was examined by MTT at 48 h and 72 h after transfection.</p><p><b>RESULT</b>The level of mRNA expression was significantly inhibited by the siRNA 48 h and 72 h after transfection, the suppression rate of survivin mRNA separately reached 85.21%, 94.35% mensurated by quantitative RT-PCR with SYBR GREEN I, cell proliferation was inhibited significantly by 45.02% and 50.88%, respectively, the apoptotic rate detected by Annexin V-FITC assay reached 12.28%and 21.55%, respectively.</p><p><b>CONCLUSION</b>The chemosynthesized siRNA targeting survivin could significantly down-regulate survivin mRNA. Survivin siRNA was able to inhibit the proliferation of leukemia cell line K562. Survivin may become a new target for leukemia gene therapy.</p>