Hongbing Ma

Potential role of exosome-associated microRNA panels and in vivo environment to predict drug resistance for patients with multiple myeloma

Multiple myeloma (MM) is the second most common hematologic neoplasms and an appropriate in vivo environment for myeloma cells has potential implications for initiation, progression, and metastasis of MM. Exosomes, entities carrying microRNAs (miRNAs) to target locations, participate in the cross-talk between myeloma cells and nonmalignant components of the in vivo environment. This study disclosed the emerging roles of circulating exosome-associated miRNAs in drug resistance (DR) of MM. To this end, the medical records of consecutively hospitalized MM patients, who received novel agents-based therapies, were analyzed. Then, an optimized procedure was established for exosome isolation and exosomal RNA analysis. The exosome-associated miRNA expression patterns for predicting bortezomib (Bz) resistance of MM were further examined using a microarray. In total, 204 patients were enrolled with DR rates of 36.5%, 73.1% and 81.8% in the bortezomib (Bz), thalidomide and lenalidomide containing groups. The serum total light chain ratio ≥ 100, CRP ≥ 20 mg/L, and the second-line usage increased risks of acquired Bz-resistance. Among 68 cases having genetic tests, a high risk factor for predicting de novo DR was 1q21 amplification, which also correlated with lower levels of cholesterol and LDL-C. Moreover, nano-sized exosomes were isolated with significantly increasing internal RNAs and down-regulation of exosomal miR-16-5p, miR-15a-5p and miR-20a-5p, miR-17-5p was revealed in the patients resistant to Bz. The routine workup of MM hardly suggested a value for DR prediction. The circulating exosomes carrying miRNAs provided a window that permits a better understanding of the in vivo intercellular crosstalk in MM patients.

Antileukaemia effect of rapamycin alone or in combination with daunorubicin on Ph+ acute lymphoblastic leukaemia cell line.

The translocation (9;22) (q34;q11), known as the Philadelphia (Ph) chromosome and bcr‐abl fusion gene, is the common cytogenetic abnormality and an unfavourable prognosis in adult acute lymphoblastic leukaemia (ALL). Although chemotherapeutic treatment produced high rates of complete response in approximately 70%–80% of newly diagnosed Ph+ ALL, the onset of resistance and clinical relapse is rapid. Therefore, the efficacy of treatment in Ph+ ALL is still to be determined. In this study, we aimed to assess the antileukemic activity of rapamycin (RAPA) (Sigma‐Aldrich Corporation, MO, USA), a mammalian target of rapamycin inhibitor, alone and in combination with daunorubicin (DNR) (Pharmacia & Upjohn Company, Germany) in a Ph+ acute lymphoblastic cell line SUP‐B15 and a primary Ph+ ALL sample in vitro. Here, we demonstrated that 50 nmol/L of RAPA significantly intensified the inhibition induced by DNR on both Ph+ ALL cell line and a primary Ph+ ALL sample. Notably, we reported that the consequence of DNR treatment induced the over expression of the componets of mammalian target of rapamycin signalling pathway, whereas RAPA effectively eliminated this deleterious side effect of DNR, which might enhance DNRs ability to kill drug‐resistant cancer. The synergistic effect was also associated with the increase in autophagy, blockage of cell cycle progression in the G1 phase. Altogether, our results suggest that DNR in combination with RAPA is more effective in the treatment of Ph+ ALL compared with DNR alone. Copyright

Association of the interferon-gamma single nucleotide polymorphism + 874(T/A) with response to immunosuppressive therapy in patients with severe aplastic anemia

The aim of this study was to investigate whether a single nucleotide polymorphism (SNP) +874T/A of interferon-gamma (IFN-γ) correlates with response to immunosuppressive therapy. Amplification refractory mutation system-polymerase chain reaction was used to amplify the polymorphic segments of the IFN-γ +874T/A gene in the samples obtained from 54 patients with aplastic anemia and 51 healthy adults. Further, enzyme linked immunosorbent assay was used to assay IFN-γ levels in the blood plasma of 35 patients with severe aplastic anemia before immune suppression therapy and 20 healthy blood donors. The results showed that the frequency of IFN-γ +874 TT genotype in patients with aplastic anemia was significantly higher than the corresponding frequency in the healthy adults (42.6% vs. 17.6%, χ(2)=13.78, p=0. 01). The response rate in severe aplastic anemia patients with increased IFN-γ levels in the blood plasma was higher than that in severe aplastic anemia patients with decreased IFN-γ levels in the blood plasma (73.7% vs. 25.0%, p<0.05). Of the 35 patients with severe aplastic anemia, 15 showed the IFN-γ +874 TT genotype, whereas response in 11 patients, the high response rate was significantly in the favor of the IFN-γ +874 TT genotype (73.3% vs. IFN-γ +874 non-TT 35%, p<0.05). In conclusion, the IFN-γ +874T/A gene polymorphism may be correlated with response to immunosuppressive therapy.

Nutlin-3 plus Tanshinone IIA Exhibits Synergetic Anti-leukemia Effect with Imatinib by Reactivating p53 and Inhibiting AKT/mTOR Pathway in Ph+ ALL

Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) is triggered by BCR/ABL kinase. Recent efforts focused on the development of more potent tyrosine kinase inhibitors (TKIs) that also inhibit mutant tyrosine kinases such as nilotinib and dasatinib. Although major advances in the treatment of this aggressive disease with potent inhibitors of the BCR/ABL kinases, patients in remission frequently relapse due to drug resistance possibly mediated, at least in part, by compensatory activation of growth-signaling pathways and protective feedback signaling of leukemia cells in response to TKI treatment. Continuous activation of AKT/mTOR signaling and inactivation of p53 pathway were two mechanisms of TKI resistance. Here, we reported that nutlin-3 plus tanshinone IIA significantly potentiated the cytotoxic and apoptotic induction effects of imatinib by down-regulation of the AKT/mTOR pathway and reactivating the p53 pathway deeply in Ph+ ALL cell line. In primary samples from Ph+ ALL patients, nutlin-3 plus tanshinone IIA also exhibited synergetic cytotoxic effects with imatinib. Of note, three samples from Ph+ ALL patients harboring T315I mutation also showed sensitivity to the combined treatment of imatinib, nutlin-3 plus tanshinone IIA. In Ph+ ALL mouse models, imatinib combined with nutlin-3 plus tanshinone IIA also exhibited synergetic effects on reduction in leukemia burden. These results demonstrated that nutlin-3 plus tanshinone IIA combined TKI might be a promising treatment strategy for Ph+ ALL patients.

Sustaining integrating imatinib and interferon-α into maintenance therapy improves survival of patients with Philadelphia positive acute lymphoblastic leukemia ineligible for allogeneic stem cell transplantation

Abstract We report the clinical results of sustainedly integrating imatinib and interferon-α into maintenance therapy in the patients ineligible for allogeneic hematopoietic stem cell transplantation (allo-HSCT). Maintenance therapy lasted for 5 years with imatinib 400 mg daily, interferon-α 3 million units, 2∼3 doses per week, and chemotherapy including vindesine and dexamethasone scheduled monthly in first year, once every 2 months in second year, and once every 3 months in third year. The chemotherapy was discontinued after 3 years and the imatinib and interferon-α continued for another 2 years. For 41 patients without allo-HSCT with a median follow-up of 32 months, the 3-year DFS and OS were 42.7  ± 8.6% and 57.9  ± 8.4%, respectively. Our study suggests that sustaining maintenance with low-dose chemotherapy, imatinib and interferon-α improved survival of adult Philadelphia-positive acute lymphoblastic leukemia (Ph + ALL) patients ineligible for allo-HSCT, and even provided an opportunity for cure. BCR/ABL persistent negativity at 6 and 9 months may have benefit to choose suitable patients for the imatinib/interferon-α maintenance strategy.