Individualized Use of 6-Mercaptopurine in Chinese Children with ALL: A Multicenter Randomized Controlled Trial.

Continuous 6-mercaptopurine (6-MP) dose titration is necessary because of its narrow therapeutic index and frequently encountered dose-limiting hematopoietic toxicity. However, evidence-based guidelines for gene-based 6-MP dosing have not been established for Chinese children with acute lymphoblastic leukemia (ALL). This multicenter, randomized, open-label, active-controlled clinical trial randomly assigned Chinese children with low- or intermediate-risk ALL in a 1:1 ratio to receive TPMT-NUDT15 gene-based dosing of 6-MP (N = 44, 10 to 50 mg/m2 /day) or standard dosing (N = 44, 50 mg/m2 /day) during maintenance therapy. The primary end point was the incidence of 6-MP myelosuppression in both groups. Secondary end points included frequencies of 6-MP hepatotoxicity, duration of myelosuppression and leukopenia, event-free survival, and steady-state concentrations of active metabolites (6-thioguaninenucleotides and 6-methylmercaptopurine nucleotides) in erythrocytes. A 2.2-fold decrease in myelosuppression, the primary end point, was observed in the gene-based-dose group using ~ 50% of the standard initial 6-MP dose (odds ratio, 0.26, 95% confidence interval, 0.11 to 0.64, P = 0.003). Patients in the gene-based-dose group had a significantly lower risk of developing thiopurine-induced myelosuppression and leukopenia (P = 0.015 and P = 0.022, respectively). No significant differences were observed in the secondary end points of the incidence of hepatotoxicity and steady-state concentrations of active metabolites in erythrocytes between the two groups. TPMT- and NUDT15-based dosing of 6-MP will significantly contribute toward further reducing the incidence of leukopenia in Chinese children with ALL. This trial is registered at www.clinicaltrial.gov as #NCT04228393.

Tyrosine Kinase Inhibitors for Pediatric Leukemia: History and Current Status.

Tyrosine kinase inhibitors (TKIs) block the activity of tyrosine kinases by competitive inhibition of ATP at the catalytic tyrosine kinase binding site and inhibit oncogenic signaling. One important target of TKIs is BCR-ABL1, which is constitutively activated in leukemia cells. In this review, we briefly describe the development of TKIs from the first generation to the third generation, and summarize their use in the treatment of chronic myeloid leukemia and acute lymphoblastic leukemia in children. We highlight several future directions in the development of TKIs for pediatric leukemia therapy. In conclusion, we focus on chronic myeloid leukemia and acute lymphoblastic leukemia as the examples of pediatric blood cancer that significantly benefit from TKIs-based target therapy. Further development of TKIs will allow us to better manage pediatric leukemia.

[Establishment of An Animal Model of Acute B Lymphoblastic Leukemia with Minimal Residual Disease].

OBJECTIVE: To establish an animal model of acute B lymphoblastic leukemia (B-ALL) with minimal residual disease. METHODS: The transplanted tumor was formed by subcutaneous injection of 2×107 Nalm-6 cells, and the body weight, activity status and tumor formation status of nude mice were observed. Peripheral blood, bone marrow, liver and spleen and other tissues of nude mice were taken for pathological examination to understand whether the success of subcutaneous modeling was accompanied by systemic metastasis. RESULTS: There were 2×107 Nalm-6 cells injected subcutaneously in nude mice, (11.0±2.5) days later, the tumors of (3-4) × (3-4) mm were observed, the body weight of the nude mice was reduced and activity showed no limited. Infiltration of tumor cells in liver, spleen and bone marrow were observed in pathological sections. CONCLUSION: The animal model of subcutaneous tumor of B-ALL was successfully established in nude mice.

[Effect of ultraviolet irradiation on the proliferation of acute promyelocytic leukemia cells under hypoxic conditions and related mechanisms].

OBJECTIVE: To study the effect of 280 nm-LED ultraviolet irradiation on the proliferation of acute promyelocytic leukemia (APL) HL-60 cells under hypoxic conditions and related mechanism. METHODS: HL-60 cells in the logarithmic growth phase were selected and divided into control, hypoxia, ultraviolet and hypoxia+ultraviolet groups. The cells in the hypoxia group were treated with cobalt chloride (with a final concentration of 150 µmol/L), those in the ultraviolet group were irradiated by 280 nm-LED ultraviolet with an energy intensity of 30 J/m2, and those in the hypoxia+ultraviolet group were treated with cobalt chloride and then irradiated by 280 nm-LED ultraviolet. After 48 hours of treatment, the cells were placed under an invert microscope to observe cell morphology. CCK-8 assay was used to measure the inhibition rate of cell proliferation. Annexin V-FITC/PI double staining flow cytometry was used to evaluate cell apoptosis. Quantitative real-time PCR was used to measure the mRNA expression of Bcl-2. Each experiment above was repeated three times independently. RESULTS: Compared with the control group, the experimental groups showed shrinkage, decreased brightness, and disordered arrangement of cells, and the number of cells decreased over the time of culture. There were significant differences in the inhibition rate of cell proliferation and cell apoptosis rate among the groups (P<0.01), and the hypoxia+ultraviolet group showed the strongest inhibition of cell proliferation and induction of cell apoptosis, followed by the ultraviolet group and the hypoxia group. Compared with the control group, the other three groups had a gradual reduction in the mRNA expression of Bcl-2, and the hypoxia+ultraviolet group had a significantly greater reduction than the hypoxia and ultraviolet groups (P<0.01). CONCLUSIONS: Both hypoxia and ultraviolet irradiation can inhibit the proliferation of HL-60 cells and induce cell apoptosis, and ultraviolet irradiation has a better effect on proliferation inhibition and cell apoptosis under hypoxic conditions than under normoxic conditions, possibly by downregulating the mRNA expression of Bcl-2.

Expression of keratinocyte growth factor and its receptor in oral lichen planus.

This study aimed to investigate the expression of keratinocyte growth factor (KGF) and its receptor KGFR in oral lichen planus (OLP). Oral mucosa specimens from 30 OLP patients and ten healthy controls were collected. The expression of KGF and KGFR proteins was detected by immunohistochemistry and the expression of KGF mRNA was detected by in situ hybridization. We observed KGF protein expression but not KGF mRNA expression in the epithelium of both OLP and normal oral mucosa. The expression intensity of KGF protein was much lower in the epithelium of OLP than in that of normal oral mucosa. KGF protein was also expressed in the cytoplasm of some fibroblasts and vascular endothelial cells in the connective tissues underlying the epithelium for both OLP and normal oral mucosa, but the expression intensity of KGF was lower in the connective tissues for OLP. KGF mRNA was expressed in the cytoplasm of some fibroblasts and vascular endothelial cells in the connective tissues underlying the epithelium for both OLP and normal oral tissues. Although KGFR was expressed in vascular endothelial cells of connective tissue and in all epithelium of normal oral mucosa, it was only expressed in the basal layer and prickle layer of the epithelium and in vascular endothelial cells of the connective tissue of OLP. Compared to normal oral mucosa, OLP had lower expression of KGFR in the epithelium but higher expression of KGFR in the connective tissue underlying the epithelium. In conclusion, this study revealed significant differences in the expression intensity and distribution of both KGF and KGFR between OLP and normal oral mucosa tissues. KGF and its receptor KGRF may play an important role in the development and progression of OLP.

Muramyl dipeptide and anti-CD10 monoclonal antibody immunoconjugate enhances anti-leukemia immunity of T lymphocytes.

It is necessary to completely eliminate minimal residual disease (MRD) to cure acute leukemia. Monoclonal antibodies (MAb) have been shown to be effective to eliminate MRD. In this study we aimed to investigate the effect of anti-CD10 MAb conjugated to muramyl dipeptide immunoconjugate (MDP-Ab) on the function of lymphocytes and activated lymphocytes using leukemia xenografts in nude mice as a model. Peripheral blood mononuclear cells were isolated from children with acute lymphoblastic leukemia and induced into dendritic cells (DCs) and lymphocytes. Cytotoxic activity of lymphocytes was detected by LDH release assay. Leukemia xenografts in nude mice were established to assess tumor growth. We found that the killing rate was significantly higher in MDP-Ab group, LPS group and MDP-Ab+LPS group than in control group, and was the highest in MDP-Ab+LPS group. Tumor-bearing mice in MDP-Ab group showed obvious coagulation necrosis. In conclusion, our data suggest that MDP-Ab could effectively prime DCs to improve the anti-tumor immunity of T lymphocytes and inhibit the tumor growth. MDP-Ab may be used as suitable candidate for eliminating residual leukemia cells to prevent relapse.

Crocin Exhibits Antitumor Effects on Human Leukemia HL-60 Cells In Vitro and In Vivo.

Crocin is a carotenoid of the saffron extract that exhibits antitumor activity against many human tumors. However, the effects of crocin on HL-60 cells in vivo have not been evaluated. This study aimed to examine the effects of crocin on HL-60 cells in vitro and in vivo and investigate the underlying mechanisms. HL-60 cells were treated by crocin, and cell proliferation, apoptosis, and cell cycle profiles were examined by MTT assay, AO/EB staining, and flow cytometry, respectively. Furthermore, HL-60 cells were xenografted into nude mice and treated by crocin, the tumor weight and size were calculated, and the expression of Bcl-2 and Bax in xenografts was detected by immunohistochemical staining. The results showed that crocin (0.625-5 mg/mL) inhibited HL-60 cell proliferation and induced apoptosis and cell cycle arrest at G0/G1 phase, in a concentration and time-dependent manner. In addition, crocin (6.25, 25 mg/kg) inhibited the tumor weight and size of HL-60 xenografts in nude mice, inhibited Bcl-2 expression, and increased Bax expression in xenografts. In summary, crocin inhibits the proliferation and tumorigenicity of HL-60 cells, which may be mediated by the induction of apoptosis and cell cycle arrest and the regulation of Bcl-2 and Bax expression.

Preparation and identification of a novel immunomodulator composed of muramyl dipeptide and anti-CD10 monoclonal antibody for treatment of minimal residual disease in acute leukemia children.

Targeted therapy is a potentially useful approach for antileukemic therapy, in particular eliminating minimal residual disease (MRD) to prevent tumor relapse. In this study, the immunomodulator (MDP-Ab) was constructed by coupling anti-CD10 monoclonal antibody (MAb) and muramyl dipeptide (MDP) using heterobifunctional reagent SPDP and the activity of MDP-Ab through dendritic cells (DCs)-based immunotherapy was identified in targeted therapy for leukemia. Results showed that the molecular ratio of purified MDP-Ab immunomodulator was about 2:1 according to electrospray ionization mass spectrometry (ESI-MS). The immunoreactivity and specificity of the new immunomodulator on CD10 antigen was identical to that of unconjugated native anti-CD10 MAb. The immunomodulatory effect of MDP-Ab immunoconjugate on peripheral blood dendritic cells (PBDCs) from children with acute lymphoblastic leukemia (ALL) exhibited upregulated expression of HLA-DR, co-stimulatory marker (CD80 and CD86) and maturity marker (CD83), increased cytokine secretion (interleukin-12, IL-12) and enhanced autostimulatory activity. These results in vitro suggested that MDP-Ab immunoconjugate may be a suitable candidate for targeting trials and support the further development of vaccination with the new immunomodulator-triggered DCs as a post-remission treatment to prevent relapse in ALL children.

Muramyl Dipeptide modulates differentiation, maturity of dendritic cells and anti-tumor effect of DC-mediated T cell in acute leukemia children.

BACKGROUND: Targeted therapy is a potentially useful approach for antileukemic therapy, in particular eliminating minimal residual disease(MRD) to prevent tumor relapse. This study was aimed to find out an effective, nontoxic dendritic cell (DC) maturating agent for the immunotherapy of acute leukemia. RESULTS: MDP-matured DCs(M-DCs) expressed higher level of phenotypic markers and secreted higher cytokine level, while lower than TNF-α-matured DCs (T-DCs) and co-administration of MDP and TNF-α-matured DCs (MT-DCs). MT-DCs promoted significantly allogeneic T-cells reaction. As a result, allogeneic T-cell proliferated significantly and secreted higher amount of IFN-γ. HL60-derived antigens were presented more effectively by MT-DCs to cytotoxic T lymphocytes (CTLs) to induce more beneficial anti-tumor effects in a dose-dependent manner. METHODS: Purified mononuclear cells (MNCs) from bone marrow of acute leukemia children were differentiated by granulocyte-macrophage colony stimulating factor (GM-CSF) and recombinant human interleukin-4 (rhIL-4) and further matured by either Muramyl Dipeptide (MDP), tumor necrosis factor-alpha (TNF-α) or co-administration of MDP and TNF-α. CONCLUSIONS: These results demonstrate MDP can be used as a candidate clinical agent for antigen specific cancer immunotherapy.