Background: Curcumin, the active component of the Curcuma longa plant, has been shown to potentiate the effect of the immunomodulatory drugs (IMiDs) thalidomide and Bortezomib against human myeloma cell lines and a nude mice model. Its effect on the other IMid, lenalidomide, has not been evaluated. This study aims to investigate the mechanism of action of curcumin and its potential ability to positively interact with lenalidomide.Method: we designed an in-vitro study to investigate the cytotoxic and chemo-sensitising effects of curcumin alone and in combination with lenalidomide on the human myeloma H929 cell line. Results:Incubation of H929 cells with curcumin (30M) or lenalidomide (2.5 mM) for 3 days resulted in 26.35% (±1.06) and 30.81%(±2.98) apoptotic cells respectively. When 30 M curcumin was combined with 2.5 mM lenalidomide, 50.4% (±3.37) apoptotic cells were detected by flow cytometry and the increase was significant compared to either curcumin alone or lenalidomide alone (anova p = 0.0026). Furthermore, gene analysis studies show that curcumin enhances the cytotoxic effect of lenalidomide via suppression of the cereblon and multi-drug resistant genes. Conclusion:Curcumin exerts a cytotoxic effect additive to that of lenalidomide on H929 myeloma cells, and it also enhances the chemo-sensitizing effects of this agent.

Immune thrombocytopenia (ITP) is a bleeding disorder caused by dysregulated B and T cell functions, which lead to platelet destruction. A well-recognised mechanism of ITP pathogenesis involves anti-platelet and anti-megakaryocyte antibodies recognising membrane glycoprotein (GP) complexes, mainly GPIb/IX and GPIIb/IIIa. In addition to the current view of phagocytosis of the opsonised platelets by splenic and hepatic macrophages via their Fc gamma receptors, antibody-induced platelet desialylation and apoptosis have also been reported to contribute to the ITP pathogenesis. Nevertheless, the relationship between the specific thrombocytopenic mechanisms and various types of antiplatelet antibodies has not been established. To ascertain such association, we used sera from 61 ITP patients and assessed the capacity of antiplatelet antibodies to induce neuraminidase 1 (NEU1) surface expression, RCA-1 lectin binding and loss of mitochondrial inner membrane potential on donors’ platelets. Sera from ITP patients with detectable antibodies caused significant platelet desialylation and apoptosis. Anti-GPIIb/IIIa antibodies appeared more capable of causing NEU1 surface translocation while anti-GPIb/IX complex antibodies resulted in a higher degree of platelet apoptosis. In ITP patients with anti-GPIIb/IIIa antibodies, both desialylation and apoptosis were dependent on Fc-gamma RIIa signalling rather than platelet activation. Finally, we confirmed in a murine model of ITP that destruction of human platelets induced by anti-GPIIb/IIIa antibodies can be prevented with the NEU1 inhibitor oseltamivir. A collaborative clinical trial is warranted to investigate the utility of oseltamivir in the treatment of ITP.

Expression of the chemokine receptor CXCR4 by haematopoietic stem cells (HSCs) is believed to influence the process of these cells 'homing' back to the bone marrow post-transplantation, in response to the stromal cell-derived factor-1 gradient, followed by engraftment. The primary aim of this retrospective study was to compare reinfused CD34(+) cell dose, assessed from the fresh collection, with the post-thaw viable (v) CD34(+) and vCD34/CXCR4(+) dual positive cell dose as predictors of haematopoietic recovery in multiple myeloma patients undergoing autologous stem cell transplantation. Cryopreserved samples from stem cell collections of 27 myeloma patients were analysed for CD34 and CXCR4 expression and times to haematological engraftment measured. Dosage of transplanted vCD34(+) cells was on average 79% of the original calculation from the fresh collection bag (range 29-98%). The median percentage of vCD34+ cells co-expressing CXCR4 was 37% (3.7-97%). Surface expression of CXCR4 by thawed vCD34(+) cells was closely correlated to complementary DNA levels. The median dose of CD34/CXCR4(+) cells in the autografts was 1.2 × 10(6)/kg (0.2-3.0 × 10(6)/kg) compared with 3.3 × 10(6)/kg for transplanted vCD34(+) cells (1.2-5.5 × 10(6)/kg). Both CD34 and vCD34 doses correlated with neutrophil engraftment (p < 0.005) although vCD34/CXCR4(+) dose did not. However, patients given a higher dose of CD34/CXCR4(+) cells (≥1.75 × 10(6)/kg) showed a faster time to platelet recovery (p < 0.05) than those given a lower dose (≤0.42 × 10(6)/kg). These results warrant further study of CD34/CXCR4 expression by mobilised HSCs and the relationship to platelet recovery post-transplantation on a larger cohort of patients.