Association of Platelet Desialylation and Circulating Follicular Helper T Cells in Patients With Thrombocytopenia.

Thrombocytopenia is a multifactorial condition that frequently involves concomitant defects in platelet production and clearance. The physiopathology of low platelet count in thrombocytopenia remains unclear. Sialylation on platelet membrane glycoprotein and follicular helper T cells (TFHs) are thought to be the novel platelet clearance pathways. The aim of this study was to clarify the roles of platelet desialylation and circulating TFHs in patients with immune thrombocytopenia (ITP) and non-ITP thrombocytopenia. We enrolled 190 patients with ITP and 94 patients with non-ITP related thrombocytopenia including case of aplastic anemia (AA) and myelodysplastic syndromes (MDS). One hundred and ten healthy volunteers were included as controls. We found significantly increased desialylated platelets in patients with ITP or thrombocytopenia in the context of AA and MDS. Platelet desialylation was negatively correlated with platelet count. Meanwhile, the circulating TFH levels in patients with thrombocytopenia were significantly higher than those of normal controls, and were positively correlated with desialylated platelet levels. Moreover, TFHs-related chemokine CXCL13 and apoptotic platelet levels were abnormally high in ITP patients. The upregulation of pro-apoptotic proteins and the activation of the MAPK/mTOR pathway were observed in the same cohort. These findings suggested that platelet desialylation and circulating TFHs may become the potential biomarkers for evaluating the disease process associated with thrombocytopenia in patients with ITP and non-ITP.

Doxorubicin/Nucleophosmin Binding Protein-Conjugated Nanoparticle Enhances Anti-leukemia Activity in Acute Lymphoblastic Leukemia Cells in vitro and in vivo.

Acute lymphoblastic leukemia (ALL) is an aggressive malignancy. Adults with ALL have more than 50% relapse rates. We have previously validated that overexpression of nucleophosmin (NPM) is involved in the multidrug resistance (MDR) development during ALL; and a synthetically engineered recombinant NPM binding protein (NPMBP) has been developed in our group; NPMBP and doxorubicin (DOX) can be conjugated in a nanoparticle-based drug delivery system named DOX-PMs-NPMBP to counteract MDR during ALL. Here, we evaluated the antileukemia potential of DOX-PMs-NPMBP in resistant ALL cells. This study demonstrates that DOX-PMs-NPMBP significantly enhances chemosensitivity to DOX in ALL cells. Despite at variable concentrations, both resistant and primary ALL cells from relapsed patients were sensitive to DOX-PMs-NPMBP. In detail, the half maximal inhibitory concentration (IC50) values of DOX-PMs-NPMBP were between 1.6- and 7.0-fold lower than those of DOX in cell lines and primary ALL cells, respectively; and apoptotic cells ratio was over 2-fold higher in DOX-PMs-NPMBP than DOX. Mechanistically, p53-driven apoptosis induction and cell cycle arrest played essential role in DOX-PMs-NPMBP-induced anti-leukemia effects. Moreover, DOX-PMs-NPMBP significantly inhibited tumor growth and prolonged mouse survival of ALL xenograft models; and no systemic toxicity occurrence was observed after treatment during follow-up. In conclusion, these data indicate that DOX-PMs-NPMBP may significantly exert growth inhibition and apoptosis induction, and markedly improve DOX antileukemia activity in resistant ALL cells. This novel drug delivery system may be valuable to develop as a new therapeutic strategy against multidrug resistant ALL.

[Effect of Baicalin Derivative 02-036 on Burkitt Lymphoma Cell Line CA46 and Its Related Mechanisms].

OBJECTIVE: To investigate the effect of baicalin derivative 02-036 on proliferation and apoptosis human Burkitt lymphoma cell line CA46 and its related mechanisms. METHODS: The MTT assay and cell colony formation assay were used to measure the growth inhibition of CA46 cells after 02-036 treatment. The flow cytometry with AnnexinV-FITC/PI double staining was employed to detect the apoptosis induction effect of 02-036 on CA46 cells. Cell cycle distribution of CA46 cells was estimeted by using DNA ploid analysis. Western blot was used to determine the changes of apoptosis-related proteins, including C-MYC, BCL-2, Procaspase-9, Procaspase-3, PARP and Cleaved-PARP. RESULTS: Baicalin derivative 02-036 obviously inhibited the proliferation of CA46 cells, with dose- and time-dependent manner (r=0.963, r=0.992). The averaged IC50 value of CA46 cells was (6.04±0.11) µmol/L after 48-hour treatment. Low concentration of 02-036 could significantly inhibit the colony formation of CA46 cells. Flow cytometry analysis confirmed that 02-036 could effectively induce CA46 cell apoptosis. The apoptosis rate correlated with drug concentrations (r=0.959). Also, DNA ploid analysis showed that the cell cycle of CA46 was arrested in the S phase. The expression levels of BCL-2, Pro-caspase-9, Pro-caspase-3, PARP and C-MYC proteins decreased with a 02-036-dose dependent manner (r values were -0.990, -0.939, -0.971 and -0.967, respectively). In contrast, the expression level of cleaved-PARP increased with the same manner (r=0.920). CONCLUSION: Baicalin derivative 02-036 can effectively inhibit the proliferation and induce apoptosis of CA46 cells, and its related mechanisms may be correlated with the down-regulation of apoptosis-related molecule expression levels, such as BCL-2, Pro-caspase-9, Pro-caspase-3, PARP and C-MYC.