Efficacy and exploratory biomarker analysis of entinostat plus exemestane in advanced or recurrent breast cancer: phase II randomized controlled trial.

BACKGROUND: We aimed to confirm the efficacy and safety of the oral histone deacetylase inhibitor entinostat in Japanese patients with hormone receptor-positive advanced/recurrent breast cancer and to explore potential biomarkers. METHODS: This phase II, double-blind, randomized, placebo-controlled trial (ClinicalTrials.gov; NCT03291886) was conducted at 28 Japanese sites (September 2017-July 2020; interim analysis cutoff: April 2019). Patients with progression/relapse following non-steroidal aromatase inhibitors were randomized 1:1 to entinostat (5 mg/week) or placebo, plus exemestane (25 mg/day). Primary endpoint was progression-free survival; secondary endpoints included overall survival and safety. Exploratory biomarker outcomes included lysine acetylation, immune cell profiles, estrogen receptor 1 mutations and plasma chemokines. RESULTS: Of 133 randomized patients, 131 (65 entinostat, 66 placebo) who received study drug were analyzed. Median (95% confidence interval) progression-free survival was 5.8 (3.2-7.8) months for entinostat and 3.3 (3.1-5.8) months for placebo (hazard ratio [95% confidence interval]: 0.75 [0.50 - 1.14]; P = 0.189). Median overall survival was not reached in either group. Entinostat tended to prolong progression-free survival in patients aged ≥65 years, not endocrine resistant, or with estrogen receptor 1 Y537S mutation. Candidate biomarkers of efficacy (progression-free survival) included lysine acetylation in CD3+ cells, plasma interferon gamma-induced protein 10, dendritic cell CD86 expression, and CD4+ cell expression of human leukocyte antigen-DR and inducible T-cell co-stimulator. Safety was similar to non-Japanese populations; however, seven entinostat-treated patients (10.8%) had reversible lung injury. CONCLUSIONS: In Japanese patients, the safety of entinostat plus exemestane was acceptable and progression-free survival was prolonged, although not significantly. Exploratory analyses identified potential biomarkers, including lysine acetylation, of efficacy.

CD38 is critical for social behaviour by regulating oxytocin secretion.

CD38, a transmembrane glycoprotein with ADP-ribosyl cyclase activity, catalyses the formation of Ca2+ signalling molecules, but its role in the neuroendocrine system is unknown. Here we show that adult CD38 knockout (CD38-/-) female and male mice show marked defects in maternal nurturing and social behaviour, respectively, with higher locomotor activity. Consistently, the plasma level of oxytocin (OT), but not vasopressin, was strongly decreased in CD38-/- mice. Replacement of OT by subcutaneous injection or lentiviral-vector-mediated delivery of human CD38 in the hypothalamus rescued social memory and maternal care in CD38-/- mice. Depolarization-induced OT secretion and Ca2+ elevation in oxytocinergic neurohypophysial axon terminals were disrupted in CD38-/- mice; this was mimicked by CD38 metabolite antagonists in CD38+/+ mice. These results reveal that CD38 has a key role in neuropeptide release, thereby critically regulating maternal and social behaviours, and may be an element in neurodevelopmental disorders.

The novel potent TEAD inhibitor, K-975, inhibits YAP1/TAZ-TEAD protein-protein interactions and exerts an anti-tumor effect on malignant pleural mesothelioma.

The Hippo signaling pathway regulates cell fate and organ development. In the Hippo pathway, transcriptional enhanced associate domain (TEAD) which is a transcription factor is activated by forming a complex with yes-associated protein 1 (YAP1) or transcriptional coactivator with PDZ-binding motif (TAZ, also called WWTR1). Hyper-activation of YAP1/TAZ, leading to the activation of TEAD, has been reported in many cancers, including malignant pleural mesothelioma (MPM). Therefore, the YAP1/TAZ-TEAD complex is considered a novel therapeutic target for cancer treatment. However, few reports have described YAP1/TAZ-TEAD inhibitors, and their efficacy and selectivity are poor. In this study, we performed a high-throughput screening of a neurofibromin 2 (NF2)-deficient MPM cell line and a large tumor suppressor kinase 1/2 (LATS1/2)-deficient non-small-cell lung cancer cell line using a transcriptional reporter assay. After screening and optimization, K-975 was successfully identified as a potent inhibitor of YAP1/TAZ-TEAD signaling. X-ray crystallography revealed that K-975 was covalently bound to an internal cysteine residue located in the palmitate-binding pocket of TEAD. K-975 had a strong inhibitory effect against protein-protein interactions between YAP1/TAZ and TEAD in cell-free and cell-based assays. Furthermore, K-975 potently inhibited the proliferation of NF2-non-expressing MPM cell lines compared with NF2-expressing MPM cell lines. K-975 also suppressed tumor growth and provided significant survival benefit in MPM xenograft models. These findings indicate that K-975 is a strong and selective TEAD inhibitor with the potential to become an effective drug candidate for MPM therapy.

Interaction between lung cancer cells and astrocytes via specific inflammatory cytokines in the microenvironment of brain metastasis.

The incidence of brain metastasis is increasing, however, little is known about molecular mechanism responsible for lung cancer-derived brain metastasis and their development in the brain. In the present study, brain pathology was examined in an experimental model system of brain metastasis as well as in human brain with lung cancer metastasis. In an experimental model, after 3-6 weeks of intracardiac inoculation of human lung cancer-derived (HARA-B) cells in nude mice, wide range of brain metastases were observed. The brain sections showed significant increase in glial fibrillary acidic protein (GFAP)-positive astrocytes around metastatic lesions. To elucidate the role of astrocytes in lung cancer proliferation, the interaction between primary cultured mouse astrocytes and HARA-B cells was analyzed in vitro. Co-cultures and insert-cultures demonstrated that astrocytes were activated by tumor cell-oriented factors; macrophage migration inhibitory factor (MIF), interleukin-8 (IL-8) and plasminogen activator inhibitor-1 (PAI-1). Activated astrocytes produced interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and interleukin-1 ß (IL-1ß), which in turn promoted tumor cell proliferation. Semi-quantitative immunocytochemistry showed that increased expression of receptors for IL-6 and its subunits gp130 on HARA-B cells. Receptors for TNF-α and IL-1ß were also detected on HARA-B cells but down-regulated after co-culture with astrocytes. Insert-culture with astrocytes also stimulated the proliferation of other lung cancer-derived cell lines (PC-9, QG56, and EBC-1). These results suggest that tumor cells and astrocytes stimulate each other and these mutual relationships may be important to understand how lung cancer cells metastasize and develop in the brain.

New molecular and biological mechanism of antitumor activities of KW-2478, a novel nonansamycin heat shock protein 90 inhibitor, in multiple myeloma cells.

PURPOSE: The heat shock protein 90 (Hsp90) plays an important role in chaperoning oncogenic client proteins in multiple myeloma (MM) cells, and several Hsp90 inhibitors have shown antitumor activities both in vitro and in vivo. However the precise mechanism of action of Hsp90 inhibitor in MM has not been fully elucidated. EXPERIMENTAL DESIGN: We evaluated the antitumor activities of KW-2478, a nonansamycin Hsp90 inhibitor, in MM cells with various chromosomal translocations of immunoglobulin heavy chain (IgH) loci both in vitro and in vivo. RESULTS: Our studies revealed that exposure of KW-2478 to MM cells resulted in growth inhibition and apoptosis, which were associated with degradation of well-known client proteins as well as a decrease in IgH translocation products (FGFR3, c-Maf, and cyclin D1), and FGFR3 was shown to be a new client protein of Hsp90 chaperon complex. In addition, KW-2478 depleted the Hsp90 client Cdk9, a transcriptional kinase, and the phosphorylated 4E-BP1, a translational inhibitor. Both inhibitory effects of KW-2478 on such transcriptional and translational pathways were shown to reduce c-Maf and cyclin D1 expression. In NCI-H929 s.c. inoculated model, KW-2478 showed a significant suppression of tumor growth and induced the degradation of client proteins in tumors. Furthermore, in a novel orthotopic MM model of i.v. inoculated OPM-2/green fluorescent protein, KW-2478 showed a significant reduction of both serum M protein and MM tumor burden in the bone marrow. CONCLUSIONS: These results suggest that targeting such diverse pathways by KW-2478 could be a promising strategy for the treatment of MM with various cytogenetic abnormalities.

Hydrogen in drinking water reduces dopaminergic neuronal loss in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mouse model of Parkinson's disease.

It has been shown that molecular hydrogen (H(2)) acts as a therapeutic antioxidant and suppresses brain injury by buffering the effects of oxidative stress. Chronic oxidative stress causes neurodegenerative diseases such as Parkinson's disease (PD). Here, we show that drinking H(2)-containing water significantly reduced the loss of dopaminergic neurons in PD model mice using both acute and chronic administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). The concentration-dependency of H(2) showed that H(2) as low as 0.08 ppm had almost the same effect as saturated H(2) water (1.5 ppm). MPTP-induced accumulation of cellular 8-oxoguanine (8-oxoG), a marker of DNA damage, and 4-hydroxynonenal (4-HNE), a marker of lipid peroxidation were significantly decreased in the nigro-striatal dopaminergic pathway in mice drinking H(2)-containing water, whereas production of superoxide (O(2)*(-)) detected by intravascular injection of dihydroethidium (DHE) was not reduced significantly. Our results indicated that low concentration of H(2) in drinking water can reduce oxidative stress in the brain. Thus, drinking H(2)-containing water may be useful in daily life to prevent or minimize the risk of life style-related oxidative stress and neurodegeneration.

Neuroprotective role of bradykinin because of the attenuation of pro-inflammatory cytokine release from activated microglia.

Bradykinin (BK) has been reported to be a mediator of brain damage in acute insults. Receptors for BK have been identified on microglia, the pathologic sensors of the brain. Here, we report that BK attenuated lipopolysaccharide (LPS)-induced release of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta from microglial cells, thus acting as an anti-inflammatory mediator in the brain. This effect was mimicked by raising intracellular cAMP or stimulating the prostanoid receptors EP2 and EP4, while it was abolished by a cAMP antagonist, a prostanoid receptor antagonist, or by an inhibitor of the inducible cyclooxygenase (cyclooxygenase-2). BK also enhanced formation of prostaglandin E(2) and expression of microsomal prostaglandin E synthase. Expression of BK receptors and EP2/EP4 receptors were also enhanced. Using physiological techniques, we identified functional BK receptors not only in culture, but also in microglia from acute brain slices. BK reduced LPS-induced neuronal death in neuron-microglia co-cultures. This was probably mediated via microglia as it did not affect TNF-alpha-induced neuronal death in pure neuronal cultures. Our data imply that BK has anti-inflammatory and neuroprotective effects in the central nervous system by modulating microglial function.