No abstract

No abstract

The human c-mpl gene (MPL) plays an important role in the development of megakaryocytes and platelets as well as the self-renewal of haematopoietic stem cells. However, numerous MPL mutations have been identified in haematopoietic diseases. These mutations alter the normal regulatory mechanisms and lead to autonomous activation or signalling deficiencies. In this review, we summarise 59 different MPL mutations and classify these mutations into four different groups according to the associated diseases and mutation rates. Using this classification, we clearly distinguish four diverse types of MPL mutations and obtain a deep understand of their clinical significance. This will prove to be useful for both disease diagnosis and the design of individual therapy regimens based on the type of MPL mutations.

Multiple myeloma (MM) is an indolent B-cell disease characterized by clonal proliferation of malignant plasma cells. Multiple myeloma remains incurable despite new targeted drugs and development of drug resistance or intolerable toxicity emerges as a major problem. Therefore, design, identification, and validation of novel chemicals with therapeutic potential are clearly needed for MM treatment. Here, we explore polyphyllin I (PPI), a major active constituent extracted from Paris polyphyllin, its inhibitory effects and its mechanisms in MM cells in vitro. We found that PPI inhibited the proliferation of myeloma cells. The combination of PPI with dexamethasone, doxorubicin, arsenic trioxide, or bortezomib enhanced the inhibition of cell growth. As analyzed by flow cytometry, MM cells were arrested at G2/M phase and apoptotic cells increased in a time-dependent manner. Morphological changes of cells undergoing apoptosis were observed under light microscope. To explore the mechanism of apoptosis induced by PPI, we next examined whether the Wingless-Int (Wnt)/β-catenin signaling pathway played a role in the PPI-induced growth inhibition in MM cells. The canonical Wnt signaling pathway is activated in MM cells through constitutively active β-catenin, a messenger molecule relevant to growth, survival, and migration of MM cells. Western blotting was used to measure the protein levels of β-catenin, and PPI treatment led to downregulating the expression of β-catenin protein and was followed by inhibition of β-catenin nuclear localization. As a result, β-catenin downstream targets, such as cyclin D1 and survivin, were downregulated. To the best of our knowledge, this is the first report identifying anti-proliferative potency of PPI against myeloma cells. PPI blocks β-catenin nuclear translocation and decreasing expression of the downstream targets of β-catenin. Our results suggest that PPI is a novel inhibitor of β-catenin activity with potential anti-myeloma efficacy.

Haematopoiesis is a self-renewing and multi-directional differentiation process of haematopoietic stem cells (HSCs), which is modulated very precisely by the haematopoietic microenvironment in bone marrow. Our previous study has demonstrated that oestrogen-deficiency leads to haematopoiesis dysfunction which manifests as a decrease in haematopoietic tissues and an increase in adipose tissues in bone marrow. However, the mechanism involved in the oestrogen-deficiency effects on haematopoiesis dysfunction is not completely understood. In this study, we established an oestrogen-deficiency rat model by ovariectomy (OVX group). Haematopoiesis was evaluated at the 12th, 16th, 20th, 24th and 28th weeks after operation in the OVX group and its control (Sham group) by pathological examination; the number and function of HSCs were evaluated by flow cytometry analysis and colony-forming assay respectively. Haematopoietic growth factors levels including granulocyte/macrophage-colony-stimulating factor (GM-CSF), stem cell factor (SCF) and interleukin-3 (IL-3) were examined by ELISA kits at different time points. We found that in the OVX group, haematopoiesis dysfunction in bone marrow was observed (P < 0.05) from the 12th week when compared with the Sham group, and extramedullary haematopoiesis began to appear in the liver and spleen from the 16th week. The number of HSCs and colony-forming units-granulocyte/macrophage (CFUs-GM) in bone marrow was reduced significantly (P < 0.05) from the 20th and 16th week respectively. Furthermore, GM-CSF, SCF and IL-3 in the OVX group decreased significantly (P < 0.05) since the 12th, 16th and 24th week respectively. Taken together, these results suggested that oestrogen is required for normal haematopoiesis. Oestrogen-deficiency inducing haematopoiesis dysfunction may be via reduction in HSCs and haematopoietic growth factors at a late stage.

Abstract:Objective: The cytotoxic effect of berbamine on chronic myeloid leukemia (CML) cell line KU812 was evaluated, and the mechanisms of its action were explored. Methods: The effect of berbamine on the KU812 cell growth was determined by methyl thiazolyl tetrazolium (MTT) assay. Flow cytometry was used to profile cell cycle alteration upon berbamine treatment. Reverse transcription polymerase chain reaction (RT-PCR) was carried out to determine the transcripts of transforming growth factor-β (TGF-β) receptors (TβRs), Smad3, c-Myc, cyclin D1, p21Cip1 (p21), and p27 Kip1 (p27). Changes in the protein levels of total Smad3, phosphorylated Smad3, the downstream targets of Smad3, and specific apoptosis-related factors were evaluated by Western blotting. Results: Berbamine inhibited KU812 cell proliferation in a dose-and time-dependent manner, and the half maximal inhibitory concentration (IC 50 ) values for treatments of 24, 48, and 72 h were 5.83, 3.43, and 0.75 μg/ml, respectively. Berbamine induced G 1 arrest as well as apoptosis in KU812 cells. Transcriptions of Smad3 and p21 were up-regulated, while those of TβRI, TβRII, c-Myc, cyclin D1 and p27 were not changed significantly. The protein levels of both total Smad3 and phosphorylated Smad3 were both up-regulated after berbamine treatment, together with decreased c-Myc and cyclin D1 and increased p21. Meanwhile, the levels of the anti-apoptotic proteins, such as Bcl-2 and Bcl-xL, were decreased, whereas pro-apoptotic Bax was increased. Conclusions: Berbamine suppresses KU812 cell proliferation through induction of cell cycle arrest in G 1 and apoptosis. It activates Smad3 without additional stimulation of TGF-β, and alters the levels of the Smad3 downstream targets, including c-Myc, cyclin D1 and p21. Our findings suggest that berbamine is a promising drug in the treatment of advanced stage patients with CML.

Multiple myeloma (MM) remains incurable despite the development and the use of new agents. In our studies, we found that 4-chlorbenzoyl berbamine (BBMD9), a novel synthetic derivative of berbamine, inhibited the proliferation of MM cells in dose- and time-dependent manners. Flow cytometric (FCM) analysis revealed that MM cells were arrested in the G1 phase and that apoptotic cells increased in a time-dependent manner. Moreover, the BBMD9 treatment downregulated IKKα and IKKβ, inhibited p-IκBα, and blocked p65 nuclear localization. Consistently, NF-κB downstream targets, such as cyclinD1 and survivin, were also reduced. In addition, BBMD9 phosphorylated the activity of JNK and c-Jun.

Background Cancer-associated fibroblasts (CAFs) aggravate gastric cancer (GC) development. Methods Combined with bioinformatics analysis and literature review, miR-223-3p had high expression in microvesicles (MVs) derived from GC CAFs, and it could modulate SORBS1. miR-223-3p and SORBS1 mRNA levels were assessed by qRT-PCR. The levels of CAFs markers, MVs markers, epithelial-mesenchymal transition (EMT)-associated proteins, and SORBS1 protein were assessed by western blot. MVs isolated from fibroblasts were observed by transmission electron microscopy. Combined with immunofluorescence and co-culture experiments, GC cells were determined to absorb MVs carrying miR-223-3p. Cell functions were measured using CCK-8, transwell, flow cytometry and colony formation assays. The binding of miR-223-3p and SORBS1 was determined by dual-luciferase assay and RNA immunoprecipitation. The cancer-promoting effect of MVs carrying miR-223-3p on experimental animals was verified in vivo by tumor-bearing experiment in nude mice. Results miR-223-3p was upregulated in the MVs secreted by GC CAFs and could be transmitted to GC cells through MVs, to boost the malignant progression of tumor cells. Additionally, it was also revealed that miR-223-3p targeted SORBS1 and accelerated progression along with EMT in GC. Conclusions CAFs-derived MVs could carry miR-223-3p to GC cells to target SORBS1, thereby promoting the malignant progression of GC.