S110, a novel decitabine dinucleotide, increases fetal hemoglobin levels in baboons (P. anubis)

<p>Abstract</p> <p>Background</p> <p>S110 is a novel dinucleoside analog that could have advantages over existing DNA methyltransferase (DNMT) inhibitors such as decitabine. A potential therapeutic role for S110 is to increase fetal hemoglobin (HbF) levels to treat β-hemoglobinopathies. In these experiments the effect of S110 on HbF levels in baboons and its ability to reduce DNA methylation of the γ-globin gene promoter in vivo were evaluated.</p> <p>Methods</p> <p>The effect of S110 on HbF and γ-globin promoter DNA methylation was examined in cultured human erythroid progenitors and in vivo in the baboon pre-clinical model. S110 pharmacokinetics was also examined in the baboon model.</p> <p>Results</p> <p>S110 increased HbF and reduced DNA methylation of the γ-globin promoter in human erythroid progenitors and in baboons when administered subcutaneously. Pharmacokinetic analysis was consistent with rapid conversion of S110 into the deoxycytosine analog decitabine that binds and depletes DNA.</p> <p>Conclusion</p> <p>S110 is rapidly converted into decitabine, hypomethylates DNA, and induces HbF in cultured human erythroid progenitors and the baboon pre-clinical model.</p

Laminin-5 β3A Expression in LNCaP Human Prostate Carcinoma Cells Increases Cell Migration and Tumorigenicity

Interactions between extracellular matrix proteins and prostate carcinoma cells change dramatically during prostate tumor progression. We have concentrated on two key modifications that occur in the hemidesmosome in prostate carcinoma: loss of laminin-5 protein expression and altered basal cell polarity of the α6β4 integrin. We previously demonstrated two cell linespecific isoforms (β3A and β3B) of the LAMB3 message. Cells expressing only the β3B isoform did not translate the β3 protein and were unable to assemble the laminin-5 trimer. One such cell line, LNCaP, was selected to determine whether restoration of the laminin-5 β3A isoform would cause expression of a functional laminin-5 β3 chain, assembly and secretion of the laminin-5 trimer, and reversion to a non-neoplastic phenotype. Laminin-5 β3A cDNA was cloned and stably transfected into LNCaP cells. We observed the restoration of the β3 protein, but a laminin-5 trimer was not secreted. Moreover, increased cell migration was demonstrated, and tumorigenicity was increased in SCID mice. A microarray analysis, performed between transfected and nontransfected LNCaP cells, showed most changing genes to be associated with signal transduction. The β3 chain of laminin-5 may thus play an important role in signal transduction, which may enhance cell motility and tumorigenesis

Inhibition of Nek2 by Small Molecules Affects Proteasome Activity

Background. Nek2 is a serine/threonine kinase localized to the centrosome. It promotes cell cycle progression from G2 to M by inducing centrosome separation. Recent studies have shown that high Nek2 expression is correlated with drug resistance in multiple myeloma patients. Materials and Methods. To investigate the role of Nek2 in bortezomib resistance, we ectopically overexpressed Nek2 in several cancer cell lines, including multiple myeloma lines. Small-molecule inhibitors of Nek2 were discovered using an in-house library of compounds. We tested the inhibitors on proteasome and cell cycle activity in several cell lines. Results. Proteasome activity was elevated in Nek2-overexpressing cell lines. The Nek2 inhibitors inhibited proteasome activity in these cancer cell lines. Treatment with these inhibitors resulted in inhibition of proteasome-mediated degradation of several cell cycle regulators in HeLa cells, leaving them arrested in G2/M. Combining these Nek2 inhibitors with bortezomib increased the efficacy of bortezomib in decreasing proteasome activity in vitro. Treatment with these novel Nek2 inhibitors successfully mitigated drug resistance in bortezomib-resistant multiple myeloma. Conclusion. Nek2 plays a central role in proteasome-mediated cell cycle regulation and in conferring resistance to bortezomib in cancer cells. Taken together, our results introduce Nek2 as a therapeutic target in bortezomib-resistant multiple myeloma

A Small-Molecule Inhibitor of PIM Kinases as a Potential Treatment for Urothelial Carcinomas

The proto-oncogene proviral integration site for moloney murine leukemia virus (PIM) kinases (PIM-1, PIM-2, and PIM-3) are serine/threonine kinases that are involved in a number of signaling pathways important to cancer cells. PIM kinases act in downstream effector functions as inhibitors of apoptosis and as positive regulators of G1-S phase progression through the cell cycle. PIM kinases are upregulated in multiple cancer indications, including lymphoma, leukemia, multiple myeloma, and prostate, gastric, and head and neck cancers. Overexpression of one or more PIM family members in patient tumors frequently correlates with poor prognosis. The aim of this investigation was to evaluate PIM expression in low- and high-grade urothelial carcinoma and to assess the role PIM function in disease progression and their potential to serve as molecular targets for therapy. One hundred thirty-seven cases of urothelial carcinoma were included in this study of surgical biopsy and resection specimens. High levels of expression of all three PIM family members were observed in both noninvasive and invasive urothelial carcinomas. The second-generation PIM inhibitor, TP-3654, displays submicromolar activity in pharmacodynamic biomarker modulation, cell proliferation studies, and colony formation assays using the UM-UC-3 bladder cancer cell line. TP-3654 displays favorable human ether-à-go-go-related gene and cytochrome P450 inhibition profiles compared with the first-generation PIM inhibitor, SGI-1776, and exhibits oral bioavailability. In vivo xenograft studies using a bladder cancer cell line show that PIM kinase inhibition can reduce tumor growth, suggesting that PIM kinase inhibitors may be active in human urothelial carcinomas

High-Throughput Virtual Screening Identifies Novel <i>N</i>′‑(1-Phenylethylidene)-benzohydrazides as Potent, Specific, and Reversible LSD1 Inhibitors

Lysine specific demethylase 1 (LSD1) plays an important role in regulating histone lysine methylation at residues K4 and K9 on histone H3 and is an attractive therapeutic target in multiple malignancies. Here we report a structure-based virtual screen of a compound library containing ∼2 million small molecular entities. Computational docking and scoring followed by biochemical screening led to the identification of a novel <i>N</i>′-(1-phenylethylidene)-benzohydrazide series of LSD1 inhibitors with hits showing biochemical IC₅₀s in the 200–400 nM range. Hit-to-lead optimization and structure–activity relationship studies aided in the discovery of compound <b>12</b>, with a <i>K</i>_i of 31 nM. Compound <b>12</b> is reversible and specific for LSD1 as compared to the monoamine oxidases shows minimal inhibition of CYPs and hERG and inhibits proliferation and survival in several cancer cell lines, including breast and colorectal cancer. Compound <b>12</b> may be used to probe LSD1’s biological role in these cancers