Liyu Zhou

Whole-exome and targeted sequencing identify ROBO1 and ROBO2 mutations as progression-related drivers in myelodysplastic syndromes

The progressive mechanism underlying myelodysplastic syndrome remains unknown. Here we identify ROBO1 and ROBO2 as novel progression-related somatic mutations using whole-exome and targeted sequencing in 6 of 16 (37.5%) paired MDS patients with disease progression. Further deep sequencing detects 20 (10.4%) patients with ROBO mutations in a cohort of 193 MDS patients. In addition, copy number loss and loss of heterogeneity (LOH) of ROBO1 and ROBO2 are frequently observed in patients with progression or carrying ROBO mutations. In in vitro experiments, overexpression of ROBO1 or ROBO2 produces anti-proliferative and pro-apoptotic effects in leukaemia cells. However, this effect was lost in ROBO mutants and ROBO-SLIT2 signalling is impaired. Multivariate analysis shows that ROBO mutations are independent factors for predicting poor survival. These findings demonstrate a novel contribution of ROBO mutations to the pathogenesis of MDS and highlight a key role for ROBO-SLIT2 signalling in MDS disease progression.

Interleukin-17-producing CD4+ T lymphocytes are increased in patients with primary immune thrombocytopenia.

The present study was performed to investigate the role of interleukin-17-producing CD4-positive T cells in the pathogenesis of primary immune thrombocytopenia (ITP). Peripheral blood was collected from ITP patients and healthy controls. The immunophenotyping of T lymphocytes and the detection of T helper 1/2/17 (Th1/Th2/Th17) cells were performed by flow cytometry, Th1/Th2/Th17-associated cytokines were determined by cytokines microarray and ELISA. The association between Th17 and T regulatory cells (Tregs) was also investigated. The percentage of Th17 and Th1 cells were markedly increased in ITP patients especially in those with severe ITP compared with normal controls. Th17 cytokines microarray revealed the upregulation of proinflammatory cytokines and downregulation of inflammatory inhibitory cytokines in ITP patients compared with that in the normal controls. Further ELISA analysis verified high levels of Th17-associated proinflammatory cytokines such as interleukin-17A/F, interleukin-6 and interleukin-23 and low levels of inflammatory inhibitory factors including interleukin-10 and transforming growth factor-&bgr; in ITP patients compared with normal controls. We also observed that the ratio of Th17/Treg was significantly higher in severe ITP than that in mild ITP and normal controls and inversely correlated with platelet count. In addition, Tregs from ITP patients could suppress the secretion of interferon-&ggr; by effector CD4-positive T cells, but had no effect on interleukin-17 production in vitro. Th17 cells are increased in ITP patients, and the inversion of Th17/Treg may contribute to the activation of autoimmunity.

Rigosertib as a selective anti-tumor agent can ameliorate multiple dysregulated signaling transduction pathways in high-grade myelodysplastic syndrome

Rigosertib has demonstrated therapeutic activity for patients with high-risk myelodysplastic syndrome (MDS) in clinical trials. However, the role of rigosertib in MDS has not been thoroughly characterized. In this study, we found out that rigosertib induced apoptosis, blocked the cell cycle at the G2/M phase and subsequently inhibited the proliferation of CD34+ cells from MDS, while it minimally affected the normal CD34+ cells. Further studies showed that rigosertib acted via the activation of the P53 signaling pathway. Bioinformatics analysis based on gene expression profile and flow cytometry analysis revealed the abnormal activation of the Akt-PI3K, Jak-STAT and Wnt pathways in high-grade MDS, while the p38 MAPK, SAPK/JNK and P53 pathways were abnormally activated in low-grade MDS. Rigosertib could markedly inhibit the activation of the Akt-PI3K and Wnt pathways, whereas it activated the SAPK/JNK and P53 pathways in high-grade MDS. A receptor tyrosine kinase phosphorylation array demonstrated that rigosertib could increase the activation of RET and PDGFR-β while reducing the activation of Tie2 and VEGFR2 in MDS cells. Taken together, these data indicate that rigosertib is a selective and promising anti-tumor agent that could ameliorate multiple dysregulated signaling transduction pathways in high-grade MDS.

Establishment and Validation of an Updated Diagnostic FCM Scoring System Based on Pooled Immunophenotyping in CD34+ Blasts and Its Clinical Significance for Myelodysplastic Syndromes

Abnormal immunophenotypes of hematopoietic cells can be detected by flow cytometry (FCM) to assist the diagnosis of myelodysplastic syndromes (MDS). We previously established a FCM scoring system for the diagnosis of low-grade MDS. In this study, additional valuable antigens were involved in an updated FCM scoring system (u-FCMSS) for all MDS subtypes. The u-FCMSS showed better sensitivity and specificity (89.4% and 96.5%) in distinguishing MDS from non-clonal cytopenia diseases. Validation analysis of u-FCMSS exhibited comparable sensitivity and specificity (86.7% and 93.3%) and high agreement rate (88.9%) of FCM diagnosis with morphological diagnosis at optimal cut-off (score 3). The distribution of FCM scores in different disease stages was also analyzed. The results suggested that early scoring from abnormal expression of mature myeloid/lymphoid antigens and advanced scoring from abnormal expression of stem/progenitor antigens expression constituted the majority of FCM scores of low-grade and high-grade MDS, respectively. High early scoring was generally accompanied by low IPSS-R score and superior survival, whereas high advanced scoring was accompanied by high IPSS-R score and inferior survival. In addition, the low-risk MDS patients with high early scoring and low advanced scoring were revealed as candidates for immunosuppressive therapy, whereas those with high advanced scoring and low early scoring may be more suitable for decitabine treatment. In conclusion, the u-FCMSS is a useful tool for diagnosis, prognosis and treatment selection in MDS. Differences in classes of antigens expressed and in distribution of FCM scores may reflect distinctive stage characteristics of MDS during disease progression.

Cytogenetic response based on revised IPSS cytogenetic risk stratification and minimal residual disease monitoring by FISH in MDS patients treated with low-dose decitabine

The features of cytogenetic response have been not well described in myelodysplastic syndrome (MDS) patients receiving low-dose decitabine treatment. In this study, we observed and analyzed the response characteristics based on the revised IPSS (IPSS-R) cytogenetic risk stratification in eighty-seven MDS patients who received low-dose decitabine treatment (15-20 mg/M(2)/d×5/per course). Twenty-seven of 44 patients (61.3%) with abnormal karyotypes achieved a cytogenetic response, including 18 cases with complete cytogenetic response (cCR). The patients carrying poor or very poor karyotypes achieved better clinical and cytogenetic response than those with intermediate or good karyotypes. Among the patients with poor or very poor karyotypes, those carrying chromosome 7 aberrance showed a better treatment response than the other patients. Four patients (22.2%) of the patients who achieved clinical CR presented with a cytogenetic PR (partial response) or NR (no response). Over 5% of the clonal cells determined by FISH analysis were in the two patients who presented cytogenetic CR. Longer median OS (24 months) were observed in the patients who achieved a cytogenetic response than in those who did not (12 months) (P=0.007). The patients with poor or very poor karyotypes could achieve survival comparable to that of the patients with good or very good karyotypes after decitabine treatment (18 vs. 20 months, P=0.365). IPSS-R cytogenetic risk stratification could be used to predict the clinical and cytogenetic response to decitabine treatment in MDS patients, and the predicting effect may be related to chromosome 7 involvement. Analysis with FISH and G-banding should be available in determining the minimal residual disease in MDS patients after treatment.

Increased PD-1/STAT1 ratio may account for the survival benefit in decitabine therapy for lower risk myelodysplastic syndrome

Abstract Decitabine is an effective therapy for patients with lower risk myelodysplastic syndrome (MDS). However, the mechanisms of decitabine’s therapeutic effect are not well established. Forty-four lower risk MDS patients received decitabine therapy. 59.1% patients achieved treatment response, and 53.8% patients who were RBC/platelet-dependent cast off the transfusion burden. The median overall survival (OS) was 19.0 months after decitabine treatment. Moreover, polarization toward type 1 in the CD8 + subset was enhanced, and a significantly increased expression of the PD-1, PD-L1, and PD-1/STAT1 ratio was observed in these lower risk MDS. The patients with amplification of PD-1/STAT1 ratio (2–4) achieved longer OS. Thus, our results suggest that the effect mechanism of decitabine toward lower risk MDS may be the moderate increase of PD-1/STAT1, which contributes to hematopoietic improvement. These findings suggest that a different PD-1-related strategy from those used to treat higher risk patients could be used for lower risk MDS patients.

Exploration of the role of gene mutations in myelodysplastic syndromes through a sequencing design involving a small number of target genes

Novel sequencing designs are necessary to supplement the recognized knowledge of myelodysplastic syndrome (MDS)-related genomic alterations. In this study, we sequenced 28 target genes in 320 Chinese MDS patients but obtained 77.2% of recall factors and 82.8% of genetic abnormalities (including karyotype abnormalities). In addition to known relationships among mutations, some specific chromosomal abnormalities were found to link to specific gene mutations. Trisomy 8 tended to be linked to U2AF1 and ZRSR2 mutations, and 20q- exhibited higher SRSF2/WT1 and U2AF1 mutation frequency. Chromosome 7 involvement accounted for up to 50% of RUNX1 mutations and 37.5% of SETBP1 mutations. Patients carrying a complex karyotype were prone to present TP53 mutations (36.1%). However, individuals with normal karyotypes rarely possessed mutations in the TP53, RUNX1 and U2AF1. Moreover, DNMT3A, TP53, SRSF2, STAG2, ROBO1/2 and WT1 predicted poor survival and high AML transformation. By integrating these predictors into international prognostic scoring system (IPSS) or revised IPSS, we built a set of mutation-based prognostic risk models. These models could layer different degrees of risk in patients more satisfactorily. In summary, this sequencing design was able to detect a number of gene mutations and could be used to stratify patients with varied prognostic risk.

Efficacy and toxicity of decitabine versus CHG regimen (low-dose cytarabine, homoharringtonine and granulocyte colony-stimulating factor) in patients with higher risk myelodysplastic syndrome: a retrospective study

Abstract Decitabine and CHG regimen (low-dose cytarabine and homoharringtonine with G-CSF) have been used for treating higher risk myelodysplastic syndrome (MDS). In this study, we retrospectively compared the efficacy and toxicity of the two regimens in 132 MDS patients. Complete remission (CR) was not significantly different between the groups (27.1% with decitabine vs. 30.6% with CHG, p = 0.657). The CR rate with decitabine (58.8%) was significantly higher than that with CHG (7.7%) (p = 0.007) among the patients with poor karyotypes. Five of 23 (21.7%) patients who failed to respond to decitabine achieved CR with CHG, while one of two patients achieved CR with decitabine after failure with CHG. Overall and relapse-free survival were not different between the groups. In conclusion, both decitabine and CHG regimen are effective for higher risk MDS; there is no cross resistance between the regimens. Decitabine might be a better choice for patients with poor karyotypes.

Decitabine of Reduced Dosage in Chinese Patients with Myelodysplastic Syndrome: A Retrospective Analysis

Decitabine has been approved for the treatment of all subtypes of myelodysplastic syndrome (MDS). However, the optimal regimen for decitabine treatment is not well established. In this study, an observational, retrospective and multi-center analysis was performed to explore the decitabine schedule for the treatment of MDS. A total of 79 patients received reduced dosage decitabine treatment (15 mg/M2/day intravenously for five consecutive days every four weeks). Fifty-three out of the 79 patients were defined as intermediate-2/high risk by international prognostic scoring system (IPSS) risk category. 67.1% of MDS patients achieved treatment response including complete response (CR) (n = 23), Partial response (n = 1), marrow CR (mCR) with hematological improvement (HI) (n = 11), mCR without HI (n = 11) and HI alone (n = 7) with a median of 4 courses (range 1–11). The median overall survival (OS) was 18.0 months. The median OS was 22.0, 17.0 and 12.0 months in the patients with CR, those with other response, and those without response, respectively. In addition, this regimen contributed to zero therapy-related death and punctual course delivery, although III or IV grade of cytopenia was frequently observed. In conclusion, the 15 mg/M2/d×5 day decitabine regimen was effective and safe for Chinese MDS patients with IPSS score of 0.5 or higher.

Distinct clinical and experimental characteristics in the patients younger than 60 years old with myelodysplastic syndromes.

Myelodysplastic syndromes (MDS) mainly occur in elderly individuals in Western countries. However, MDS is commonly found in young individuals (<60 years) in Asia. The reason for the high incidence in younger individuals is still unclear, and the differences in disease features between young and elderly patients with MDS have been not well recognized. To explore these issues, in this study, we analyzed the clinical and experimental characteristics of MDS in the patients younger and older than 60 years old and characterized the potential age-associated differences. The results showed that over half of the patients with MDS (61.9%) were younger than 60 years old upon the first diagnosis. The younger patients were more likely to be female, who have lower risk and less advanced MDS. The occurrence of trisomy 8 and bone marrow failure were more frequent in the younger patients than the older ones. The marrow CD34+ cells in the younger patients showed lower proliferation and higher apoptosis in comparison with that in the older ones. Obvious amplification of T cells and low CFU formation could be found in the younger patients. CFU formation was significantly increased in the younger patients after the removal of activated T cells. In addition, the younger patients had a lower frequency of p15INK4B methylation, longer survival expectancy and less AML transformation. In summary, the younger patients with MDS in China may show more benign disease features than the older ones. Enhanced immunological response may be involved in the pathogenesis of MDS in the patients younger than 60 years.