Xi-xi Li

Epigenetic dysregulation of ID4 predicts disease progression and treatment outcome in myeloid malignancies

Promoter hypermethylation‐mediated inactivation of ID4 plays a crucial role in the development of solid tumours. This study aimed to investigate ID4 methylation and its clinical relevance in myeloid malignancies. ID4 hypermethylation was associated with higher IPSS scores, but was not an independent prognostic biomarker affecting overall survival (OS) in myelodysplastic syndrome (MDS). However, ID4 hypermethylation correlated with shorter OS and leukaemia‐free survival (LFS) time and acted as an independent risk factor affecting OS in acute myeloid leukaemia (AML). Moreover, ID4 methylation was significantly decreased in the follow‐up paired AML patients who achieved complete remission (CR) after induction therapy. Importantly, ID4 methylation was increased during MDS progression to AML and chronic phase (CP) progression to blast crisis (BC) in chronic myeloid leukaemia (CML). Epigenetic studies showed that ID4 methylation might be one of the mechanisms silencing ID4 expression in myeloid leukaemia. Functional studies in vitro showed that restoration of ID4 expression could inhibit cell proliferation and promote apoptosis in both K562 and HL60 cells. These findings indicate that ID4 acts as a tumour suppressor in myeloid malignancies, and ID4 methylation is a potential biomarker in predicting disease progression and treatment outcome.

Overexpression of miR-216b: prognostic and predictive value in acute myeloid leukemia†

Accumulating studies have shown that miR‐216b acted as a tumor suppressor and was down‐regulated in solid tumors. However, little studies revealed the role or clinical implication of miR‐216b in blood cancers. Herein, we reported miR‐216b expression and its clinical significance in patients with acute myeloid leukemia (AML). In the current study, we analyzed bone marrow (BM) miR‐216b expression in 115 de novo AML patients examined by real‐time quantitative PCR. Notably, BM miR‐216b expression was significantly up‐regulated in AML patients, and could serve as a potential biomarker distinguishing AML from controls. No significant correlations of BM miR‐216 expression were found with sex, age, white blood cells, hemoglobin, platelets, BM blasts, French–American–British classifications, and karyotypes. Significantly, patients with high miR‐216b expression tended to have a lower frequency of FLT3‐ITD mutation and higher incidence of U2AF1 and IDH1/2 mutations. Moreover, complete remission (CR) rate and overall survival were negatively affected by BM miR‐216b overexpression among cytogenetically normal AML (CN‐AML). Cox regression analyses showed that high BM miR‐216b expression may act as an independent risk factor in CN‐AML patients. Among the follow‐up patients, BM miR‐216b level in CR phase was markedly lower than in diagnosis time, and was returned in relapse phase. Collectively, our findings indicated that miR‐216b overexpression was a frequent event in de novo AML, and independently conferred a poor prognosis in CN‐AML. Moreover, miR‐216b expression was a valuable biomarker correlated with disease recurrence in AML.

Hypomethylation-mediated H19 overexpression increases the risk of disease evolution through the association with BCR-ABL transcript in chronic myeloid leukemia†

Previous study has revealed that H19 expression is required for efficient tumor growth induced by BCR‐ABL in chronic myeloid leukemia (CML). Herein, we further determined H19 expression and its clinical implication in patients with CML. H19 expression and methylation were detected by real‐time quantitative PCR and real‐time quantitative methylation‐specific PCR, and then clinical implication of H19 expression was further analyzed. H19 expression was significantly up‐regulated in CML patients (p < 0.001). H19 expression with an area under receiver operating characteristic curve value of 0.824 might serve as a promising biomarker in distinguishing CML patients from controls. The patients with high H19 expression had a tendency of higher white blood cells and BCR‐ABL transcript than those with low H19 expression. H19 overexpression occurred with the higher frequency in blast crisis stage (11/11, 100%), lower in accelerated phase (3/5, 60%), and chronic phase (42/62, 66%) stages. Moreover, paired patients during disease progression with increased BCR‐ABL transcript also showed a significant upregulation of H19 expression. Meanwhile, H19 expression was decreased in follow‐up patients who achieved complete molecular remission after tyrosine kinase inhibitors‐based therapy. Epigenetic studies showed that H19 differentially methylated region/imprinting control region (DMR/ICR) was hypomethylated and associated with H19 expression in CML patients. Moreover, demethylation of H19 DMR/ICR reactivated H19 expression in K562 cells. Collectively, H19 overexpression, a frequent event in CML, was associated with higher BCR‐ABL transcript involving in disease progression. Moreover, H19 DMR/ICR hypomethylation in CML may be one of the mechanisms mediating H19 overexpression.

Low NKD1 expression predicts adverse prognosis in cytogenetically normal acute myeloid leukemia

Dysregulation of NKD1 has been identified in several solid tumors. However, the status of NKD1 expression and its clinical implication in acute myeloid leukemia remain largely elusive. NKD1 transcript level in bone marrow mononuclear cells was detected by real-time quantitative polymerase chain reaction in 126 de novo acute myeloid leukemia patients and 30 controls. Clinical significance of NKD1 expression was obtained by the comparison between the patients with low and high NKD1 expression. NKD1 messenger RNA level was significantly decreased in acute myeloid leukemia patients compared with controls (p = 0.019). There were no significant differences between patients with low and high NKD1 expression in sex, age, peripheral blood cells, bone marrow blasts, French–American–British/World Health Organization subtypes, and karyotypes/karyotypic classifications (p > 0.05). Although no significant difference was observed in complete remission rate between NKD1low and NKD1high patients (p > 0.05), Kaplan–Meier analysis revealed that NKD1low patients showed shorter overall survival time than NKD1high patients in whole-cohort acute myeloid leukemia, non-M3 acute myeloid leukemia, and cytogenetically normal acute myeloid leukemia (p = 0.014, 0.063, and 0.020). Multivariate analyses disclosed the low NKD1 expression was an independent risk factor in cytogenetically normal acute myeloid leukemia patients (hazard ratio = 0.397, p = 0.017). Moreover, the prognostic value of NKD1 expression was confirmed by gene expression profile data in cytogenetically normal acute myeloid leukemia patients (p = 0.028 and 0.011). NKD1 showed significantly increased level after induction chemotherapy achieved complete remission in follow-up paired acute myeloid leukemia patients (p < 0.001). These findings indicated that reduced NKD1 expression is associated with unfavorable clinical outcome in cytogenetically normal acute myeloid leukemia.

CDH1 (E-cadherin) expression independently affects clinical outcome in acute myeloid leukemia with normal cytogenetics

Abstract Background: Epithelial-mesenchymal transition (EMT) is a critical process which involves in tumor metastasis. As an important EMT marker gene, CDH1 (E-cadherin) expression and its clinical implication in acute myeloid leukemia (AML) remain largely elusive. Methods: Real-time quantitative PCR (RQ-PCR) was carried out to examine CDH1 transcript level in 123 de novo AML patients and 34 controls. Results: Compared with controls, CDH1 was significantly downregulated in AML (p<0.001). The median level of CDH1 expression divided total AML patients into CDH1 low-expressed (CDH11ow) and CDH1 high-expressed (CDH1high) groups. There were no significant differences between the two groups in age, peripheral blood cell counts, complete remission (CR) rate, and the distribution of FAB/WHO subtypes as well as karyotypes/karyotypic classifications (p>0.05). However, CDH11ow group tended to have a higher bone marrow (BM) blasts (p=0.093). The spearman correlation analysis further illustrated a trend towards a negative correlation between CDH1 expression level and BM blasts (r=–0.214, p=0.052). CDH1low group had a tendency towards a lower frequency of N/K-RAS mutations (p=0.094). Furthermore, CDH1low patients had markedly shorter overall survival (OS) time in cytogenetic normal AML (CN-AML) (p=0.019). Both univariate and multivariate analyses confirmed the prognostic value of CDH1 expression in CN-AML patients (p=0.027 and 0.033, respectively). Conclusions: CDH1 downregulation acted as an independent prognostic biomarker in CN-AML patients.

High bone marrow miR-19b level predicts poor prognosis and disease recurrence in de novo acute myeloid leukemia

Oncogenic role of miR-19 family has been identified in human cancers especially in lymphoid malignancies. However, to date, little studies investigated the role of miR-19 family in myeloid malignancies. Herein, we examined miR-19a/b expression and explored its clinical significance in de novo acute myeloid leukemia (AML). The detection of miR-19a/b expression was performed by real-time quantitative PCR in bone marrow mononuclear cells of 113 patients and 42 healthy donors. Both miR-19a/b levels were significantly increased in AML patients in contrast to controls. Patients with miR-19a/b overexpression were more frequently occurred in female, and had an older age. Moreover, cases with miR-19a overexpression had a higher frequency of U2AF1, C-KIT and CEBPA mutations, whereas miR-19b overexpressed cases harbored U2AF1 and IDH1/2 mutations. There was no significant association of miR-19a overexpression with complete remission (CR) rate and overall survival (OS) among whole-cohort AML, non-M3 AML, and cytogenetically normal AML (CN-AML). However, although miR-19b overexpression was not correlated with CR rate, patients with miR-19b overexpression presented significantly shorter OS in whole-cohort AML and a trend in non-M3 AML and CN-AML patients. Importantly, our data also showed that miR-19a/b expression level at CR phase was lower than diagnosis time, and was returned to primary level even higher when at relapse phase. Our findings revealed that miR-19a/b overexpression were frequent events in de novo AML patients. Moreover, up-regulation of miR-19b expression was associated with poor prognosis and disease recurrence in AML.

H19 overexpression promotes leukemogenesis and predicts unfavorable prognosis in acute myeloid leukemia

BackgroundThe long non-coding RNA H19 plays a crucial role in solid tumor initiation and progression. However, the potential role of H19 and its clinical significance in acute myeloid leukemia (AML) remain largely elusive.MethodsH19 expression was detected by qPCR, and clinical significance in AML patients was further analyzed. The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) data for AML were used as validation cohorts. The roles of H19 in cell proliferation and apoptosis were determined by cell proliferation assay and flow cytometry analysis.ResultsH19 expression was significantly increased in AML patients but not associated with embedded miR-675 expression. Moreover, H19 overexpression was not dependent on the methylation pattern in H19 differentially methylated region/imprinting control region. Strong association was observed between H19 overexpression and patients’ characteristics including sex, higher white blood cells, older age, and intermediate karyotype, FLT3-ITD, and DNMT3A mutations. In addition, H19 overexpression correlated with lower complete remission (CR) rate and shorter overall survival, and further confirmed by multivariate analyses. Importantly, the prognostic effect of H19 expression was validated by TCGA and GEO data. In the follow-up of patients, H19 expression in CR phase was lower than diagnosis time and returned at relapse time. Loss-of-function experiments showed that H19 exhibited anti-proliferative and pro-apoptotic effects in leukemic cell HL60. Furthermore, H19 expression was positively correlated with potential downstream gene ID2 in AML.ConclusionsOur findings revealed that methylation-independent H19 was a prognostic and predictive biomarker in AML, and H19/ID2 played crucial roles in leukemogenesis with potential therapeutic target value.

KRAS overexpression independent of RAS mutations confers an adverse prognosis in cytogenetically normal acute myeloid leukemia

The prognostic value of RAS mutations has been systematically investigated in acute myeloid leukemia (AML). However, clinical significance of RAS expressions in AML remains poorly determined. To explore the clinical significance, we analyzed KRAS and NRAS expressions in 143 de novo AML patients by real-time quantitative PCR. KRAS and NRAS expressions were significantly up-regulated in AML patients. KRAS and NRAS mutations were identified in 4% (6/143) and 8% (12/143) of these patients, respectively. However, no significant association was observed between RAS mutations and expressions. High KRAS expression was associated with older age, higher white blood cells, and a tendency of higher platelets, whereas high NRAS expression was only correlated with older age. Complete remission (CR) rate and overall survival of AML patients were adversely affected by KRAS overexpression, but not NRAS overexpression. Multivariate analysis revealed that KRAS acted as an independent prognostic predictor in cytogenetically normal AML (CN-AML). Moreover, the prognostic value of KRAS expression was validated using the published data from Gene Expression Omnibus datasets. In the follow-up patients, KRAS expression rather than NRAS expression in CR time tended to decrease compared to newly diagnosis time, and both KRAS and NRAS expressions were significantly increased when in relapse time. Our findings revealed that RAS overexpression and mutations were common events in AML with potential therapeutic target value. KRAS overexpression independent of RAS mutations conferred an adverse prognosis in CN-AML.

Methylation-associated DOK1 and DOK2 down-regulation: potential biomarkers for predicting adverse prognosis in acute myeloid leukemia†

DOK‐1 and DOK‐2 (DOK1/2) are closely related members of downstream of tyrosine kinase (DOK) family genes, which are found to be frequently rearranged in several hematopoietic cancers. However, the clinical implications of DOK1/2 in acute myeloid leukemia (AML) remain largely unknown. To investigate the clinical significance, real‐time quantitative PCR (RQ‐PCR) was carried out to detect DOK1/2 expressions in 125 de novo AML patients and 28 healthy controls. Real‐time quantitative methylation‐specific PCR (RQ‐MSP) and bisulfite sequencing PCR (BSP) were applied to detect DOK1/2 methylation level and density. DOK1/2 expressions were significantly down‐regulated in AML patients. The promoters of DOK1/2 were highly hypermethylated and negatively correlated with DOK1/2 expressions in AML patients. In addition, we also confirmed that DOK1/2 expressions could be restored by DOK1/2 demethylation using 5‐aza‐2′‐deoxycytidine in leukemia cell line THP‐1. Survival analyses showed that low‐expressed DOK1/2 were associated with markedly shorter overall survival and leukemia free survival in both whole‐cohort AML and non‐M3 AML patients. Multivariate analyses further revealed that DOK1/2 were act as independent prognostic factors in AML patients. These findings indicate that decreased DOK1/2 expressions associated with their promoter hypermethylations predict adverse prognosis in AML.

Methylation-independent CHFR expression is a potential biomarker affecting prognosis in acute myeloid leukemia†

CHFR acts as a tumor suppressor gene, which is frequently inactivated caused by its promoter hypermethylation in various solid tumors. Although a recent study showed that CHFR hypermethylation was a frequent event in acute myeloid leukemia (AML) and correlated with adverse clinical outcome, herein, we found that CHFR methylation was a rare event in patients with myeloid malignancies (including AML, chronic myeloid leukemia, and myelodysplastic syndromes), but its expression may serve as an independent prognostic biomarker in AML. CHFR expression was assessed by real‐time quantitative PCR, whereas CHFR methylation was detected by methylation‐specific PCR and bisulfite sequencing PCR. In AML patients, lower CHFR expression was associated with lower complete remission (CR) rate, and CHFR expression was significantly increased in CR after chemotherapy. Moreover, patients with lower CHFR expression showed shorter overall survival and leukemia‐free survival, and multivariate analysis confirmed that lower CHFR expression was an independent risk factor in AML. Importantly, the prognostic value of CHFR expression was validated using the published Gene Expression Omnibus datasets. Notably, CHFR promoter was nearly unmethylated in patients with myeloid malignancies. Our findings revealed that lower CHFR expression was independently associated with unfavorable prognosis in AML. Moreover, aberrant CHFR promoter methylation was a rare event in myeloid malignances.