Targeting low-risk myelodysplastic syndrome with novel therapeutic strategies.

Myelodysplastic syndrome (MDS) is a group of hematopoietic disorders with limited treatment options. Anemia is a common symptom in MDS, and although erythropoiesis-stimulating agents such as erythropoietin, lenalidomide, and luspatercept are available to treat anemia, many MDS patients do not respond to these first-line therapies. Therefore, alternative drug development strategies are needed to improve therapeutic efficacy. Splicing modulators to correct splicing-related defects have shown promising results in clinical trials. Targeting differentiation of early erythroid progenitors to increase the erythroid output in MDS is another novel approach, which has shown encouraging results at the pre-clinical stage. Together, these therapeutic strategies provide new avenues to target MDS symptoms untreatable previously.

Muscarinic acetylcholine receptor regulates self-renewal of early erythroid progenitors.

Adult stem and progenitor cells are uniquely capable of self-renewal, and targeting this process represents a potential therapeutic opportunity. The early erythroid progenitor, burst-forming unit erythroid (BFU-E), has substantial self-renewal potential and serves as a key cell type for the treatment of anemias. However, our understanding of mechanisms underlying BFU-E self-renewal is extremely limited. Here, we found that the muscarinic acetylcholine receptor, cholinergic receptor, muscarinic 4 (CHRM4), pathway regulates BFU-E self-renewal and that pharmacological inhibition of CHRM4 corrects anemias of myelodysplastic syndrome (MDS), aging, and hemolysis. Genetic down-regulation of CHRM4 or pharmacologic inhibition of CHRM4 using the selective antagonist PD102807 promoted BFU-E self-renewal, whereas deletion of Chrm4 increased erythroid cell production under stress conditions in vivo. Moreover, muscarinic acetylcholine receptor antagonists corrected anemias in mouse models of MDS, aging, and hemolysis in vivo, extending the survival of mice with MDS relative to that of controls. The effects of muscarinic receptor antagonism on promoting expansion of BFU-Es were mediated by cyclic AMP induction of the transcription factor CREB, whose targets up-regulated key regulators of BFU-E self-renewal. On the basis of these data, we propose a model of hematopoietic progenitor self-renewal through a cholinergic-mediated "hematopoietic reflex" and identify muscarinic acetylcholine receptor antagonists as potential therapies for anemias associated with MDS, aging, and hemolysis.

The possible roles of B-cell novel protein-1 (BCNP1) in cellular signalling pathways and in cancer.

B-cell novel protein-1 (BCNP1) or Family member of 129C (FAM129C) was identified as a B-cell-specific plasma-membrane protein. Bioinformatics analysis predicted that BCNP1 might be heavily phosphorylated. The BCNP1 protein contains a pleckstrin homology (PH) domain, two proline-rich (PR) regions and a Leucine Zipper (LZ) domain suggesting that it may be involved in protein-protein interactions. Using The Cancer Genome Atlas (TCGA) data sets, we investigated the correlation of alteration of the BCNP1 copy-number changes and mutations in several cancer types. We also investigated the function of BCNP1 in cellular signalling pathways. We found that BCNP1 is highly altered in some types of cancers and that BCNP1 copy-number changes and mutations co-occur with other molecular alteration events for TP53 (tumour protein P53), PIK3CA (Phosphatidylinositol-4,5-Bisphosphate 3-Kinase, Catalytic Subunit Alpha), MAPK1 (mitogen-activated protein kinase-1; ERK: extracellular signal regulated kinase), KRAS (Kirsten rat sarcoma viral oncogene homolog) and AKT2 (V-Akt Murine Thymoma Viral Oncogene Homolog 2). We also found that PI3K (Phoshoinositide 3-kinase) inhibition and p38 MAPK (p38 mitogen-activated protein kinase) activation leads to reduction in phosphorylation of BCNP1 at serine residues, suggesting that BCNP1 phosphorylation is PI3K and p38MAPK dependent and that it might be involved in cancer. Its degradation depends on a proteasome-mediated pathway.