Saori Ishizaka

Nuclear factor-ĸB plays a critical role in both intrinsic and acquired resistance against endocrine therapy in human breast cancer cells

Since more than 75% of breast cancers overexpress estrogen receptors (ER), endocrine therapy targeting ER has significantly improved the survival rate. Nonetheless, breast cancer still afflicts women worldwide and the major problem behind it is resistance to endocrine therapy. We have previously shown the involvement of nuclear factor-κB (NF-κB) in neoplastic proliferation of human breast cancer cells; however, the association with the transformation of ER-positive cells remains unclear. In the current study, we focused on roles of NF-κB in the hormone dependency of breast cancers by means of ER-positive MCF-7 cells. Blocking of NF-κB signals in ER-negative cells stopped proliferation by downregulation of D-type cyclins. In contrast, the MCF-7 cells were resistant to NF-κB inhibition. Under estrogen-free conditions, the ER levels were reduced when compared with the original MCF-7 cells and the established cell subline exhibited tamoxifen resistance. Additionally, NF-κB participated in cell growth instead of the estrogen-ER axis in the subline and consequently, interfering with the NF-κB signals induced additive anticancer effects with tamoxifen. MMP-9 production responsible for cell migration, as well as the cell expansion in vivo, were suppressed by NF-κB inhibition. Therefore, we suggest that NF-κB is a master switch in both ER-positive and ER-negative breast cancers.

Skin pH is the Master Switch of Kallikrein 5-Mediated Skin Barrier Destruction in a Murine Atopic Dermatitis Model.

Elevated skin surface pH has been reported in patients with atopic dermatitis. In this study, we explored the role of skin pH in the pathogenesis of atopic dermatitis using the NC/Tnd murine atopic dermatitis model. Alkalinization of the skin of asymptomatic NC/Tnd mice housed in specific pathogen-free conditions induced kallikrein 5 and activated protease-activated receptor 2, resulting in thymic stromal lymphopoietin secretion and a cutaneous T-helper 2 allergic response. This was associated with increased transepidermal water loss and development of eczematous lesions in these specific pathogen-free NC/Tnd mice, which normally do not suffer from atopic dermatitis. Injection of recombinant thymic stromal lymphopoietin also induced scratching behavior in the specific pathogen-free NC/Tnd mice. Thymic stromal lymphopoietin production and dermatitis induced by alkalinization of the skin could be blocked by the protease-activated receptor 2 antagonist ENMD-1068. In contrast, weak acidification of eczematous skin in conventionally housed NC/Tnd mice reduced kallikrein 5 activity and ameliorated the dermatitis. Onset of the dermatitis was associated with increased epidermal filaggrin expression and impaired activity of the sodium/hydrogen exchanger 1, a known regulator of skin pH. We conclude that alterations in skin pH directly modulate kallikrein 5 activity leading to skin barrier dysfunction, itch, and dermatitis via the protease-activated receptor 2-thymic stromal lymphopoietin pathway.

Antifungal effects of palmitic acid salt and ultrapure soft water on Scedosporium apiospermum

Scedosporium apiospermum sometimes causes serious infectious diseases on the skin of immunodeficient subjects. Antifungal effects of fatty acid salts in soap against S. apiospermum were investigated under different water conditions.

Ultra-pure Soft Water Ameliorates Atopic Skin Disease by Preventing Metallic Soap Deposition in NC/Tnd Mice and Reduces Skin Dryness in Humans.

Mineral ions in tap water react with fatty acids in soap, leading to the formation of insoluble precipitate (metallic soap) on skin during washing. We hypothesised that metallic soap might negatively alter skin conditions. Application of metallic soap onto the skin of NC/Tnd mice with allergic dermatitis further induced inflammation with elevation of plasma immunoglobulin E and proinflammatory cytokine expression. Pruritus and dryness were ameliorated when the back of mice was washed with soap in Ca2+- and Mg2+-free ultra-pure soft water (UPSW). Washing in UPSW, but not tap water, also protected the skin of healthy volunteers from the soap deposition. Furthermore, 4 weeks of showering with UPSW reduced dryness and pruritus of human subjects with dry skin. Washing with UPSW may be therapeutically beneficial in patients with skin troubles.

Production of stem cell factor in canine mast cell tumors

Mast cell tumor (MCT) is the most common cutaneous tumor in dogs. We recently revealed that production of stem cell factor (SCF) contributes to the proliferation of neoplastic mast cells in an autocrine/paracrine manner. The aim of the present study was to determine the contribution of the mechanism in clinical MCTs. In consequence, high SCF expression (>10 times compared to HRMC cells) was observed in 5 of 7 MCT samples used in the study regardless of KIT mutation, which was confirmed in immunohistochemical analysis. In addition, production of SCF was observed in Ki-67-positive cells in the MCT xenograft. These results indicate the broad contribution of SCF autocrine/paracrine mechanism on clinical MCTs, providing the rationale for the clinical use of KIT inhibitors regardless of KIT mutation.

Oral Administration of Fermented Probiotics Improves the Condition of Feces in Adult Horses

ABSTRACT The effects of probiotics on horses are still controversial. The present study was a randomized, double-blinded, placebo-controlled crossover study designed to evaluate the ability of probiotics to improve intestinal conditions in adult horses. Fermented probiotics were administered to 10 healthy adult geldings for 28 days. The clinical condition of the horses was monitored daily, and the blood and feces were biochemically analyzed every 14 days. In the probiotic-treated group, the concentration of carboxylic acids in the feces was increased at days 14 and 28. In contrast to the fecal pH in the control group, which increased at days 14 and 28, the fecal pH in the probiotic-treated group did not increase. Additionally, the relative amounts of enteropathogenic bacterial DNA were diminished in the probiotic-treated group. These results suggest that probiotic bacteria proliferated in the equine intestine. No instances of abnormal clinical conditions or abnormal values in blood tests were observed throughout the study. Oral administration of fermented probiotics may have the ability to improve the intestinal environment biochemically and microbiologically without the risk of adverse effects.

Topical Application of Ketoprofen Improves Gait Disturbance in Rat Models of Acute Inflammation

Arthritis is a disabling health problem and commonly develops in the late stages of life; the condition is typically accompanied by chronic pain. For the assessment of pain severity and therapeutic effects of analgesic drugs, we recently developed a gait analysis system, which provides an index of pain severity based on walking stride disturbance. Using this system, we evaluated the therapeutic effect of topical nonsteroidal anti-inflammatory drugs (NSAIDs) in rat models of acute inflammation. We found that the gait analysis system is more sensitive than conventional evaluation methods, such as measurement of swelling or analgesia, which indicated the superiority of our system for drug screening. The approach also indicated that ketoprofen is superior to other NSAIDs for providing pain relief because of its higher skin permeability. To the best of our knowledge, this is the first report demonstrating the effectiveness of topical NSAIDs in experimental animal models of acute inflammation.

A molecular targeting against nuclear factor-κB, as a chemotherapeutic approach for human malignant mesothelioma

Chronic inflammation due to the absorption of asbestos is an important cause of mesothelioma. Although the increased prevalence of mesothelioma is a serious problem, the development of effective chemotherapeutic agents remains incomplete. As the nuclear factor‐κB (NF‐κB) pathway contributes to malignant transformation of various types of cells, we explored NF‐κB activity in three different pathological types of malignant mesothelioma cells, and evaluated the therapeutic potential of a recently reported NF‐κB inhibitor, IMD‐0354. NF‐κB was constantly activated in MSTO‐211H, NCI‐H28, and NCI‐H2052 cells, and the proliferation of these cell lines was inhibited by IMD‐0354. D‐type cyclins were effectively suppressed in mixed tissue type MSTO‐211H, leading to cell cycle arrest at sub G1/G1 phase. IMD‐0354 reduced cyclin D3 in both epithelial tissue type NCI‐H28 and sarcomatoid tissue type NCI‐H2052. In a sphere formation assay, IMD‐0354 effectively decreased the number and diameter of MSTO‐211H spheres. Preincubation of MSTO‐211H cells with IMD‐0354 delayed tumor formation in transplanted immunodeficient mice. Furthermore, administration of IMD‐0354 markedly rescued the survival rate of mice that received intrathoracic injections of MSTO‐211H cells. These results indicate that a targeted drug against NF‐κB might have therapeutic efficacy in the treatment of human malignant mesothelioma.

Mast cell hyperactivity underpins the development of oxygen-induced retinopathy

Mast cells are classically thought to play an important role in protection against helminth infections and in the induction of allergic diseases; however, recent studies indicate that these cells also contribute to neovascularization, which is critical for tissue remodeling, chronic inflammation, and carcinogenesis. Here, we demonstrate that mast cells are essential for sprouting angiogenesis in a murine model of oxygen-induced retinopathy (OIR). Although mouse strains lacking mast cells did not exhibit retinal neovascularization following hypoxia, these mice developed OIR following infusion of mast cells or after injection of mast cell tryptase (MCT). Relative hypoxia stimulated mast cell degranulation via transient receptor potential ankyrin 1. Subsequent surges in MCT stimulated retinal endothelial cells to produce monocyte chemotactic protein-1 (MCP1) and angiogenic factors, leading to sprouting angiogenesis. Mast cell stabilizers as well as specific tryptase and MCP1 inhibitors prevented the development of OIR in WT mice. Preterm infants with early retinopathy of prematurity had markedly higher plasma MCT levels than age-matched infants without disease, suggesting mast cells contribute to human disease. Together, these results suggest therapies that suppress mast cell activity should be further explored as a potential option for preventing eye diseases and subsequent blindness induced by neovascularization.

A point mutation in the extracellular domain of KIT promotes tumorigenesis of mast cells via ligand-independent auto-dimerization

Mutations in the juxtamembrane and tyrosine kinase domains of the KIT receptor have been implicated in several cancers and are known to promote tumorigenesis. However, the pathophysiological manifestations of mutations in the extracellular domain remain unknown. In this study, we examined the impact of a mutation in the extracellular domain of KIT on mast cell tumorigenesis. A KIT mutant with an Asn508Ile variation (N508I) in the extracellular domain derived from a canine mast cell tumor was introduced into IC-2 cells. The IC-2N508I cells proliferated in a cytokine-independent manner and showed KIT auto-phosphorylation. Subcutaneous injection of IC-2N508I cells into the dorsal area of immunodeficient BALB/c-nu/nu mice resulted in the formation of solid tumors, but tumor progression was abrogated by treatment with a tyrosine kinase inhibitor (STI571). In addition, the N508I mutant KIT protein dimerized in the absence of the natural ligand, stem cell factor. Structure modeling indicates that the increased hydrophobicity of the mutant led to the stabilization of KIT dimers. These results suggest that this extracellular domain mutation confers a ligand-independent tumorigenic phenotype to mast cells by KIT auto-dimerization that is STI571-sensitive. This is the first report demonstrating the tumorigenic potential of a mutation in the extracellular domain of KIT.