Preclinical and phase I clinical studies of KW-2450, a dual IGF-1R/IR tyrosine kinase inhibitor, in combination with lapatinib and letrozole.

Background: KW-2450 is an oral dual insulin-like growth factor-1 receptor/insulin receptor tyrosine kinase inhibitor. We investigated the and preclinical activity of KW-2450 plus lapatinib and letrozole and conducted a phase I trial of the triple-drug combination in one male and 10 postmenopausal female patients with advanced/metastatic hormone receptor-positive, human epidermal growth factor receptor 2 (HER2)-positive breast cancer.

Methods: A series of and animal studies was undertaken of KW-2450 in combination with lapatinib and hormonal agents.

Epirubicin, Identified Using a Novel Luciferase Reporter Assay for Foxp3 Inhibitors, Inhibits Regulatory T Cell Activity.

Forkhead box protein p3 (Foxp3) is crucial to the development and suppressor function of regulatory T cells (Tregs) that have a significant role in tumor-associated immune suppression. Development of small molecule inhibitors of Foxp3 function is therefore considered a promising strategy to enhance anti-tumor immunity. In this study, we developed a novel cell-based assay system in which the NF-κB luciferase reporter signal is suppressed by the co-expressed Foxp3 protein.

Tributylhexadecylphosphonium bromide, a novel nuclear factor of activated T cells signaling inhibitor, blocks interleukin-2 induction associated with inhibition of p70 ribosomal protein S6 kinase phosphorylation.

Transcriptional factors of the nuclear factor of activated T cells (NFAT) family are involved in T cell signaling. Many NFAT signaling inhibitors, such as cyclosporin A (CsA) and tacrolimus, abrogate dephosphorylation of NFAT proteins by inhibiting calcineurin activity. In pursuit of a novel type of NFAT signaling inhibitor, we screened our chemical library using the NFAT-dependent reporter assay and identified tributylhexadecylphosphonium bromide (THPB) as a selective NFAT signaling inhibitor.

KW-2449, a novel multikinase inhibitor, suppresses the growth of leukemia cells with FLT3 mutations or T315I-mutated BCR/ABL translocation.

KW-2449, a multikinase inhibitor of FLT3, ABL, ABL-T315I, and Aurora kinase, is under investigation to treat leukemia patients. In this study, we examined its possible modes of action for antileukemic effects on FLT3-activated, FLT3 wild-type, or imatinib-resistant leukemia cells. KW-2449 showed the potent growth inhibitory effects on leukemia cells with FLT3 mutations by inhibition of the FLT3 kinase, resulting in the down-regulation of phosphorylated-FLT3/STAT5, G(1) arrest, and apoptosis.

Novel and orally active 5-(1,3,4-oxadiazol-2-yl)pyrimidine derivatives as selective FLT3 inhibitors.

5-(1,3,4-Oxadiazol-2-yl)pyrimidine derivative 1 was identified as a new class of FLT3 inhibitor from our compound library. With the aim of enhancement of antitumor activity of 2 prepared by minor modification of 1, structure optimization of side chains at the 2-, 4-, and 5-positions of the pyrimidine ring of 2 was performed to improve the metabolic stability. Introduction of polar substituents on the 1,3,4-oxadiazolyl group contributed to a significant increase in the metabolic stability.

A novel FLT3 inhibitor FI-700 selectively suppresses the growth of leukemia cells with FLT3 mutations.

Purpose: The aim of this study was to evaluate the antileukemia activity of a novel FLT3 kinase inhibitor, FI-700.

Experimental Design: The antileukemia activity of FI-700 was evaluated in human leukemia cell lines, mutant or wild-type (Wt)-FLT3-expressing mouse myeloid precursor cell line, 32D and primary acute myeloid leukemia cells, and in xenograft or syngeneic mouse leukemia models.

Results: FI-700 showed a potent IC(50) value against FLT3 kinase at 20 nmol/L in an in vitro kinase assay.

Effect of cisplatin treatment on speckled distribution of a serine/arginine-rich nuclear protein CROP/Luc7A.

The C-half of cisplatin resistance-associated overexpressed protein (CROP), an SR-related protein, comprises domains rich in arginine and glutamate residues (RE domain), and is rich in arginine and serine residues (RS domain). We analyzed the role of the individual domains of CROP in cellular localization, subnuclear localization, and protein-protein interaction. CROP fused with green fluorescent protein, GFP-CROP, localized exclusively to the nucleus and showed a speckled intranuclear distribution.