Recently, a new experimental stromal hyperplasia animal model corresponding to clinical benign prostatic hyperplasia (BPH) was established. The main objective of this study was to elucidate the roles of the intermediate-conductance Ca 2ϩ -activated K ϩ channel (K Ca 3.1) in the implanted urogenital sinus (UGS) of stromal hyperplasia BPH model rats. Using DNA microarray, real-time polymerase chain reaction, Western blot, and/or immunohistochemical analyses, we identified the expression of K Ca 3.1 and its transcriptional regulators in implanted UGS of BPH model rats and prostate needle-biopsy samples and surgical prostate specimens of BPH patients. We also examined the in vivo effects of a K Ca 3.1 blocker, 1-[(2-chlorophenyl)diphenylmethyl]-1H-pyrazole (TRAM-34), on the proliferation index of implanted UGS by measurement of UGS weights and proliferating cell nuclear antigen immunostaining. K Ca 3.1 genes and proteins were highly expressed in implanted UGS rather than in the normal host prostate. In the implanted UGS, the gene expressions of two transcriptional regulators of K Ca 3.1, repressor element 1-silencing transcription factor and c-Jun, were significantly down-and up-regulated, and the regulations were correlated negatively or positively with K Ca 3.1 expression, respectively. Positive signals of K Ca 3.1 proteins were detected exclusively in stromal cells, whereas they were scarcely immunolocalized to basal cells of the epithelium in implanted UGS. In vivo treatment with TRAM-34 significantly suppressed the increase in implanted UGS weights compared with the decrease in stromal cell components. Moreover, significant levels of K Ca 3.1 expression were observed in human BPH samples. K Ca 3.1 blockers may be a novel treatment option for patients suffering from BPH.

We have established a new experimental stromal hyperplasia model corresponding to clinical benign prostatic hyperplasia in terms of the composition of stromal components and functional differentiation of the prostate. Furthermore, the localization and time course of growth factor expression were also similar to those in men with benign prostatic hyperplasia.

Approximately 25–40% of patients with lung cancer show bone metastasis. Bone modifying agents reduce skeletal-related events (SREs), but they do not significantly improve overall survival. Therefore, novel therapeutic approaches are urgently required. In this study, we investigated the anti-tumor effect of TAS-115, a VEGFRs and HGF receptor (MET)-targeted kinase inhibitor, in a tumor-induced bone disease model. A549-Luc-BM1 cells, an osteo-tropic clone of luciferase-transfected A549 human lung adenocarcinoma cells (A549-Luc), produced aggressive bone destruction associated with tumor progression after intra-tibial (IT) implantation into mice. TAS-115 significantly reduced IT tumor growth and bone destruction. Histopathological analysis showed a decrease in tumor vessels after TAS-115 treatment, which might be mediated through VEGFRs inhibition. Furthermore, the number of osteoclasts surrounding the tumor was decreased after TAS-115 treatment. In vitro studies demonstrated that TAS-115 inhibited HGF-, VEGF-, and macrophage-colony stimulating factor (M-CSF)-induced signaling pathways in osteoclasts. Moreover, TAS-115 inhibited Feline McDonough Sarcoma oncogene (FMS) kinase, as well as M-CSF and receptor activator of NF-κB ligand (RANKL)-induced osteoclast differentiation. Thus, VEGFRs/MET/FMS-triple inhibition in osteoclasts might contribute to the potent efficacy of TAS-115. The fact that concomitant dosing of sunitinib (VEGFRs/FMS inhibition) with crizotinib (MET inhibition) exerted comparable inhibitory efficacy for bone destruction to TAS-115 also supports this notion. In conclusion, TAS-115 inhibited tumor growth via VEGFR-kinase blockade, and also suppressed bone destruction possibly through VEGFRs/MET/FMS-kinase inhibition, which resulted in potent efficacy of TAS-115 in an A549-Luc-BM1 bone disease model. Thus, TAS-115 shows promise as a novel therapy for lung cancer patients with bone metastasis.

We generated a series of monochain HLA class I knock-in (KI) mouse strains, in which a chimeric HLA class I molecule (α1/α2 domain of HLA-A*0201, HLA-A*0301, HLA-A*2402, or HLA-A*3101 and α3 domain of H-2D) was covalently linked with 15 aa to human β-microglobulin (βm) and introduced into the endogenous mouse βm locus. In homozygous KI mice, mouse βm gene disruption resulted in loss of the endogenous H-2 class I molecules and reduction in the peripheral CD8 T cell population that was partially restored by monochain HLA class I expression. A gene dosage-dependent expression of HLA, similar to that in human PBMCs, was detected in heterozygous and homozygous HLA KI mice. Upon vaccination with various virus epitopes, HLA-restricted, epitope-specific CTLs were induced in HLA KI mice, similar to the response in the commonly used HLA transgenic mice. Importantly, the CTL responses induced in heterozygous KI mice were similar to those in homozygous KI mice. These results suggest that coexpression of H-2 class I does not affect HLA-restricted CTL responses in HLA KI mice, which differs from the situation reported for monochain HLA Tg × β2m mice. Furthermore, we generated double KI mice harboring two different HLA (HLA-A*2402 and HLA-A*0301) KI alleles, which showed a CTL response against both HLA-A24 and HLA-A3 epitopes when immunized with a mixture of both peptides. These results indicated that this HLA class I KI mouse model provides powerful research tools not only for the study of HLA class I-restricted CTL responses, but also for preclinical vaccine evaluation.

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