Zhijian Xiao

Indirubin and Meisoindigo in the Treatment of Chronic Myelogenous Leukemia in China

The aim of this review is to summarize our experience and the current knowledge on the clinical results of Indirubin, a minor active constituent of a well-know traditional Chinese prescription, Ganggui Luhui Wan, and its analogue, Meisoindigo, in the treatment of chronic myelogenous leukemia (CML) in China. Indirubin and meisoindigo induced hematologic remission in patients with chronic phase (CP) CML as effective as hydroxyurea and busulfan, in addition, there were no significant differences in median duration of CP, median survival and blast crisis at 60 months from diagnosis in indirubin, meisoindigo, hydroxyurea and busulfan treated groups. However, when meisoindigo was combined with hydroxyurea, there was evidence of a significantly prolonged median duration of CP, median survival and a reduced incidence of blast crisis at 60 months compared with busulfan, meisoindigo and hydroxyurea alone. The critical mechanisms of indirubin and meisoindigo action have not yet been identified. Both antiproliferative and induced apoptosis mechanisms have been described. Further research, especially randomized trials, are required to confirm the role of indirubin and meisoindigo in the treatment of CML.

Distinct clustering of symptomatic burden among myeloproliferative neoplasm patients: retrospective assessment in 1470 patients

Symptom burden in myeloproliferative neoplasms (MPNs) is heterogeneous even among patients within the same MPN diagnosis. Using cluster analysis from prospectively gathered symptom burden data in 1470 international patients with essential thrombocythemia (ET), polycythemia vera (PV), or myelofibrosis (MF), we assessed for the presence of clusters and relationship to disease features and prognosis. In MF (4 clusters identified), clusters significantly differed by Dynamic International Prognostic Scoring System (DIPSS) risk (P < .001), leukopenia (P = .009), thrombocytopenia (P < .001), and spleen size (P = .02). Although an association existed between clusters and DIPSS risk, high symptom burden was noted in some low and intermediate-1-risk MF patients. In PV (5 clusters identified), total symptom score increased across clusters (P < .001), but clusters did not significantly differ by PV risk or the risk assessment variable of age. Among ET patients (5 clusters identified), clusters differed by gender (P = .04), anemia (P = .01), and prior hemorrhage (P = .047). Total symptom score increased across clusters (P < .001), but clusters did not significantly differ by International Prognostic Score for ET risk including the risk assessment variables. Significant symptom heterogeneity exists within each MPN subtype, sometimes independent of disease features or prognosis.

Calreticulin mutations in Chinese with primary myelofibrosis

We tested 357 Chinese with primary myelofibrosis for mutations in CALR, JAK2 and MPL. CALR mutations were detected in 76 subjects (21%). There were 24 (32%) type-1 (L367fs*46) and 49 (64%) type-2 (K385fs*47) mutations. Seventy-two of 168 subjects (43%) without a JAK2 or MPL mutation had a CALR mutation. Subjects with a type-2 CALR mutation had lower hemoglobin concentrations (P=0.001), lower WBC counts (P<0.001), a higher percentage of blood blasts (P=0.009), and higher conventional (P<0.001) and Chinese-adjusted Dynamic International Prognostic Scoring System (P<0.001) scores compared with subjects with JAK2 mutations. Subjects with a type-2 CALR mutation were also likely to have abnormal platelet levels (<100 × 109/L, P=0.01 or >450 × 109/L, P=0.042) and no splenomegaly (P=0.004). Type-2 CALR mutation or no detectable mutation was an independent high-risk factor for survival in multivariate analyses. These data suggest the ratio between type-1 and type-2 mutations is reversed in Chinese with primary myelofibrosis compared with populations of subjects with primary myelofibrosis of predominately European descent. The unfavorable prognostic impact of CALR mutations in Chinese with primary myelofibrosis is only seen in those with type-2 mutations. These data underscore the need to evaluate the prognostic impact of genetic mutations in different populations.

Reversal of P-glycoprotein-mediated multidrug resistance with small interference RNA (siRNA) in leukemia cells.

The multidrug resistance (MDR) mediated by P-glycoprotein (P-gp), the MDR1 gene product, is one of the major obstacles in leukemia treatment. The present study was designed to explore a MDR1-targeted small interfering RNA (si-MDR1) approach for reversal of P-gp-mediated MDR in the MDR human leukemia cell line k562/A02. It was found that si-MDR1 significantly inhibited MDR1 expression at both mRNA and protein levels. Depletion of MDR1 by si-MDR1 correlated with the increased sensitivity of the cells to cytotoxic agents and with the enhanced intracellular retention of daunorubicin (DNR). One base-pair mutated control (si-MDR1-Mut) lost the effect of si-MDR1 on both the degradation of mdr1 mRNA and the reduction of P-gp expression. These findings indicate that siRNA specifically and efficiently interferes with the expression of mdr1 and could be used as a molecularly defined therapeutic approach for MDR in the treatment of leukemia.

Symptomatic Profiles of Patients With Polycythemia Vera: Implications of Inadequately Controlled Disease

PURPOSE Polycythemia vera (PV) is a myeloproliferative neoplasm (MPN) associated with disabling symptoms and a heightened risk of life-threatening complications. Recent studies have demonstrated the effectiveness of JAK inhibitor therapy in patients with PV patients who have a history of prior hydroxyurea (HU) use (including resistance or intolerance), phlebotomy requirements, and palpable splenomegaly. We aimed to determine how these features contribute alone and in aggregate to the PV symptom burden. PATIENTS AND METHODS Through prospective evaluation of 1,334 patients with PV who had characterized symptom burden, we assessed patient demographics, laboratory data, and the presence of splenomegaly by disease feature (ie, known HU use, known phlebotomy requirements, splenomegaly). RESULTS The presence of each feature in itself is associated with a moderately high symptom burden (MPN symptom assessment form [SAF] total symptom score [TSS] range, 27.7 to 29.2) that persists independent of PV risk category. In addition, symptoms incrementally increase in severity with the addition of other features. Patients with PV who had all three features (PV-HUPS) faced the highest total score (MPN-SAF TSS, 32.5) but had similar individual symptom scores to patients with known HU use (PV-HU), known phlebotomy (PV-P), and splenomegaly (PV-S). CONCLUSION The results of this study suggest that patients with PV who have any one of the features in question (known HU use, known phlebotomy, or splenomegaly) have significant PV-associated symptoms. Furthermore, it demonstrates that many PV symptoms remain severe independent of the number of features present.

TET2, ASXL1 and EZH2 mutations in Chinese with myelodysplastic syndromes

Somatic mutations of epigenetic gene regulators are common in patients with myelodysplastic syndromes (MDS) and correlate with some clinical and laboratory features. We studied mutations in TET2, ASXL1 and EZH2 in 153 Chinese patients with MDS. TET2 mutations were detected in 35 patients (23%), ASXL1 in 33 patients (22%) and EZH2 in 8 (5%). ASXL1 mutations were associated with increased colony formation of BFU-E, CFU-E and CFU-GM (P-values, 0.049, 0.011 and 0.006). EZH2 mutations were common in patients with poor IPSS cytogenetics (P=0.001) and in patients in the IPSS intermediate-2/high-risk cohorts (P=0.06). In uni- but not multi-variate analyses, mutated TET2 was associated with longer survival (P=0.044) whereas EZH2 mutations were associated with an increased risk of transformation to acute myeloid leukemia (AML; P=0.039). These data suggest ASXL1 mutations might results in dominance of the mutant clone in Chinese with MDS whereas EZH2 mutations might predict an increased risk of transformation to AML.

Neuropilin-1 in acute myeloid leukemia: Expression and role in proliferation and migration of leukemia cells

Neuropilin-1 (NRP-1) is a novel receptor of vascular endothelial growth factor (VEGF) and expressed in endothelial cells and tumor cells. The role of NRP-1 in the growth and progression of leukemia is unknown. Here we studied the mRNA expression and effect of NRP-1 in leukemic cells. Our results showed that NRP-1 mRNA was expressed in six of seven leukemic cell lines and primary leukemias derived from all 24 patients with acute myeloid leukemia (AML). Reduced NRP-1 expression by RNA interference led to a decrease of VEGF-mediated mitogenic and migration responses in acute myeloid leukemic cell line HEL. Increased NRP-1 expression was directly correlated with the blast percentage in both peripheral blood and bone marrow of AML patients. Our data demonstrated that a higher level of NRP-1 mRNA was expressed in leukemias and NRP-1 promoted proliferation and chemotaxis of leukemic cells in response to VEGF. Inhibition of NRP-1 functions may provide a new therapeutic strategy for treatment of AML.

Unique cytogenetic features of primary myelodysplastic syndromes in Chinese patients.

Myelodysplastic syndromes (MDS) are a heterogeneous group of myeloid neoplasms. Chromosomal abnormalities have been detected in 40-70% patients with primary MDS and are heterogeneous among patients of different races and from different backgrounds. In the current study, 351 Chinese adult patients with primary MDS were retrospectively analyzed for their chromosomal abnormalities by karyotyping. Among the 237 cases (67.5%) of chromosomal abnormalities, 99 were copy number changes alone (41.7%), 70 were structural abnormalities alone (29.5%), and 68 displayed both of these changes (28.8%). Overall, the frequency of -5/5q-/del(5)(q13-33) was 5.1% in these Chinese MDS patients, which was lower than that in the MDS patients of western countries (8.7-23.4%), and the incidence of 5q- syndrome was only 0.3% in Chinese MDS patients. On the other hand, the frequencies of trisomy 8 (19.1%) and -20/20q-/del(20)(q11-13) (9.4%) were higher than those in western countries (1.2-7.0% and 2.0-3.5%, respectively). Chromosomal translocations were also detected in 31 cases (13.1%) including 12 rare translocations that have not been reported in MDS patients before. In addition, i(17)(q10) was detected in nine cases (3.8%), of which six cases only had this single abnormality. According to the IPSS chromosomal prognostic classification, the incidence of poor-risk karyotypes increased in the advanced WHO subtypes (p < 0.001). Together, we detected the unique cytogenetic features of chromosomal abnormalities and some rare translocations of MDS among Chinese patients.

Stress hematopoiesis reveals abnormal control of self-renewal, lineage bias, and myeloid differentiation in Mll partial tandem duplication (Mll-PTD) hematopoietic stem/progenitor cells.

One mechanism for disrupting the MLL gene in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) is through partial tandem duplication (MLL-PTD); however, the mechanism by which MLL-PTD contributes to MDS and AML development and maintenance is currently unknown. Herein, we investigated hematopoietic stem/progenitor cell (HSPC) phenotypes of Mll-PTD knock-in mice. Although HSPCs (Lin(-)Sca1(+)Kit(+) (LSK)/SLAM(+) and LSK) in Mll(PTD/WT) mice are reduced in absolute number in steady state because of increased apoptosis, they have a proliferative advantage in colony replating assays, CFU-spleen assays, and competitive transplantation assays over wild-type HSPCs. The Mll(PTD/WT)-derived phenotypic short-term (ST)-HSCs/multipotent progenitors and granulocyte/macrophage progenitors have self-renewal capability, rescuing hematopoiesis by giving rise to long-term repopulating cells in recipient mice with an unexpected myeloid differentiation blockade and lymphoid-lineage bias. However, Mll(PTD/WT) HSPCs never develop leukemia in primary or recipient mice, suggesting that additional genetic and/or epigenetic defects are necessary for full leukemogenic transformation. Thus, the Mll-PTD aberrantly alters HSPCs, enhances self-renewal, causes lineage bias, and blocks myeloid differentiation. These findings provide a framework by which we can ascertain the underlying pathogenic role of MLL-PTD in the clonal evolution of human leukemia, which should facilitate improved therapies and patient outcomes.

Unique features of primary myelofibrosis in Chinese

Clinical and laboratory features of 642 consecutive Chinese subjects with primary myelofibrosis (PMF) were analyzed and compared with those of 1054 predominately white subjects with PMF. Chinese subjects were significantly younger, fewer had constitutional symptoms, and fewer had a palpable spleen or liver. Anemia, in contrast, was significantly more common in Chinese as was an increased white blood cell count and low platelet count. The reason for these differences is unclear, but it does not seem to be correlated with delayed diagnosis. A small but significantly increased proportion of Chinese had the JAK2(V617F) mutation but no difference in the frequency of haplotypes associated with PMF in whites. Survival of Chinese with PMF was also significantly longer than that of whites with PMF. We found commonly used staging systems for PMF such as the International Prognostic Scoring System and the Dynamic International Prognostic Scoring System were suboptimal predictors of survival in Chinese with PMF, and we developed a revised prognostic score that should help in comparison of data between studies of PMF in different populations and planning of clinical trials.