Akihiro Yoneta

Influence of isoflavone intake and equol-producing intestinal flora on prostate cancer risk.

BACKGROUND The age-adjusted incidence rate of prostate cancer (PCa) has been reported to be lower among Asians than Western populations. A traditional Japanese meal, high in soybean products or isoflavones, may be associated with a decreased risk of PCa. Equol, which is converted from daidzein by human intestinal flora, is biologically more active than any other isoflavone aglycone. MATERIALS AND METHODS We reviewed not only recent epidemiological studies on association of isoflavones with PCa risk, but also recent research on human intestinal bacteria responsible for converting daidzein into equol. Studies were systematically searched from the database published within the last 5 years of from 2008-2012. RESULTS Five out of 6 articles showed significant association of isoflavones with a decreased risk of PCa, and two of them consistently showed that equol-producers carry a significantly reduced risk of PCa. Furthermore, 5 human intestinal bacteria that can convert daidzein into equol were identified in the last 5 years. CONCLUSIONS If equol can reduce risk of PCa, a possible strategy for reducing the risk of PCa may be to increase the proportion of equol-producers by changing the intestinal flora to carrying an equol-producing bacterium with dietary alteration or probiotic technology.

Downregulation of CXCR-2 but not CXCR-1 expression by human keratinocytes by UVB.

Interleukin‐8 (IL‐8) belongs to the CXC chemokine family. IL‐8 exerts its biological activities by binding to specific cell surface receptors, CXCR‐1 and CXCR‐2. Both receptors bind IL‐8 with high affinity but they have different affinities for MGSA/Groα and NAP‐2. It has been shown that the expression of epidermal CXCR‐2 is increased in psoriasis, suggesting that activation of KC mediated by CXCR‐2 contributes to the characteristic epidermal changes observed in psoriasis. In order to examine the mechanism(s) by which UVB therapy is effective for several dermatoses including psoriasis, we sought to examine if UVB would modulate the expression of CXCR‐1 and CXCR‐2 in human keratinocytes (KC). Constitutive expression of CXCR‐1 and CXCR‐2 mRNA was detected by RT‐PCR in normal cultured human KC. After 100 or 300 J/m2 irradiation, a decrease in CXCR‐2 mRNA was detectable from 12 h after irradiation; this downregulation was observed until 48 h after irradiation. In contrast, the CXCR‐1 mRNA level was unchanged. Immunohistochemical studies and flow cytometry analysis confirmed the suppressive effect of UVB on the expression of CXCR‐2 protein in cultured human keratinocytes. Immunohistochemical studies on two minimal erythema doses (2MED)‐exposed and 2MED‐unexposed skin from healthy volunteers revealed that CXCR‐2 staining occurred over the whole layer of the epidermis but at 24 h after 2MED irradiation, the positive staining of CXCR‐2 was decreased. A faint CXCR‐1 staining was observed in the lower part of the epidermis both in unexposed and exposed skins. Our results indicate that UVB‐induced growth inhibition of KC in hyperproliferative skin disorders may, in part, be related to downregulation of CXCR‐2. J. Cell. Physiol. 182:366–370, 2000.

ΔNp63 Controls a TLR3-Mediated Mechanism That Abundantly Provides Thymic Stromal Lymphopoietin in Atopic Dermatitis

In the skin lesions of atopic dermatitis (AD), keratinocytes release large quantities of thymic stromal lymphopoietin (TSLP), causing unfavorable inflammation along with skin damage. Nevertheless, how TSLP influences keratinocytes themselves is still unknown. In this study, we showed that ΔNp63, a p53-homologue, predominantly expressed in keratinocytes regulated the receptor complex of TSLP, which determines susceptibility to self-derived TSLP. Expression of TSLP receptors in skin tissues and keratinocytes was assessed by immunohistochemistry and quantitative RT-PCR, and in vitro studies were also performed to examine the functional relevance of ΔNp63 in the expression of TSLP receptors and the constituting autocrine and/or paracrine pathway of TSLP under the condition of stimuli to innate receptors sensing cell damage. The results showed that normal keratinocytes in the upper epidermis preferentially expressed TSLP receptors and conversely lacked ΔNp63, which has an inhibitory effect on the expression of TSLP receptors. Interestingly, the epidermis of AD lesions was found to abundantly contain keratinocytes with low or undetectable levels of ΔNp63 (ΔNp63lo/-). Moreover, in the absence of ΔNp63, keratinocytes readily presented TSLP and other cytokines by stimuli through Toll-like receptor 3 (TLR3). Together with the evidence that extrinsic TSLP itself augments TSLP production by keratinocytes without ΔNp63, the results indicate that ΔNp63lo/- keratinocytes generate TSLP through a putative autocrine and/or paracrine pathway upon TLR3 stimulation within AD lesions, since moieties of damaged cells and pathogens stimulate TLR3.

Pigmented mammary Paget's disease mimicking melanoma: report of three cases

Pigmented mammary Pagets disease (PMPD) is a rare subtype of mammary Pagets disease. The differential diagnosis of PMPD and melanoma is difficult clinically and sometimes histopathologically. Here we present three cases of PMPD with a variable-sized lesion. All cases showed an irregular-shaped black-brown macule, one of which was accompanied by nipple retraction. Dermoscopically, all cases showed reticular pigmentation with or without irregular black dots, regression structures and streaks, which were indistinguishable from those of melanoma. In all but one of the cases, preoperative examinations confirmed the presence of a subcutaneous mammary lesion. All patients underwent a total mastectomy with the histopathological results indicating invasive ductal carcinoma. These cases emphasize how difficult it is to distinguish PMPD from melanoma. Dermoscopic features also mimic those of melanoma, but the reticular pigmentation seen in all cases could be a feature specific to PMPD. For suspicious cases, histopathological assessment using immunohistochemistry is highly recommended.

Macrophage Inhibitory Cytokine-1: A New Player in Melanoma Development

Macrophage inhibitory cytokine-1 (MIC-1) is a divergent member of the TGF-beta superfamily. Although it has been reported to exhibit both tumorigenic and antitumorigenic activities, Boyle et al. report in this issue that MIC-1 expression was correlated with the tumorigenicity of melanoma cells. The elucidation of signaling pathways around MIC-1 might contribute to prospective targeting therapy for melanoma.

Circulating melanoma cells as a potential biomarker to detect metastasis and evaluate prognosis

TNM staging is mainly used to evaluate the prognosis of melanoma patients. Serum biomarkers such as 5‐S‐cysteinyldopa (5‐S‐CD) have occasionally been used but most do not respond until the tumour burden becomes high. Recently, circulating melanoma cells (CMC) have been reported as a possible new biomarker to detect metastasis, monitor treatment response and predict prognosis. The object of this exploratory study was to evaluate the efficacy of CMC to detect metastasis and predict prognosis by cross‐sectional and prospective observational analyses, respectively. Altogether 15 patients with stages II–IV melanoma were enrolled and CMC were enumerated by CellSearch system with cut‐off values of two cells/7.5 mL. Serum 5‐S‐CD and lactate dehydrogenase (LDH) were also measured. The sensitivity of CMC and 5‐S‐CD for the detection of metastasis was 33 and 50%, respectively. The combination of CMC and 5‐S‐CD showed a sensitivity of 67%, the best performance among CMC, 5‐S‐CD, LDH and any combination of two of the markers. Additionally, a 30‐month prospective observation showed that CMC could segregate patients with poorer prognosis. The median survival time for the patients with <2 CMC and those with ≥2 CMC was 19.5 and 4.5 months, respectively. The limitation of this study is the small sample size. These preliminary results indicate CMC may complement the efficacy of 5‐S‐CD to detect metastasis and can be a prognostic marker. Although there is still room for improvement to maximise the sensitivity, the CellSearch system is reproducible, standardised and suitable for multi‐centre studies.

Punctate palmoplantar keratoderma type 1: a novel AAGAB mutation and efficacy of etretinate.

Punctate palmoplantar keratoderma type 1 (PPKP1, OMIM#148600), also known as the Buschke-FischerBraurer type, is a rare form of palmoplantar keratoderma that is autosomal dominantly inherited (1). PPKP1 is clinically characterised by multiple punctate hyperkeratotic papules affecting the palmar and plantar skin, with considerable phenotypic variation among patients (2). These circumscribed papules gradually coalesce and increase in number with age (2). The lesions typically start to appear in early adolescence but sometimes develop later in life. In 2012, linkage analysis and whole-exome sequencing identified heterozygous null mutations within AAGAB as a cause of PPKP1 (2, 3). AAGAB encodes αand γ-adaptin binding protein p34, which is involved in clathrin-mediated vesicle transport (2). Loss-of-function mutations in AAGAB result in haploinsufficiency of p34 (2). To date, 20 AAGAB null variants have been identified in Scottish, Irish, English, German, Tunisian, Chinese Mexican and Japanese populations (2–8). Here we report a Japanese case with PPKP1 carrying a novel AAGAB null mutation.

Melanoma-Targeted Chemothermotherapy and In Situ Peptide Immunotherapy through HSP Production by Using Melanogenesis Substrate, NPrCAP, and Magnetite Nanoparticles

Exploitation of biological properties unique to cancer cells may provide a novel approach to overcome difficult challenges to the treatment of advanced melanoma. In order to develop melanoma-targeted chemothermoimmunotherapy, a melanogenesis substrate, N-propionyl-4-S-cysteaminylphenol (NPrCAP), sulfur-amine analogue of tyrosine, was conjugated with magnetite nanoparticles. NPrCAP was exploited from melanogenesis substrates, which are expected to be selectively incorporated into melanoma cells and produce highly reactive free radicals through reacting with tyrosinase, resulting in chemotherapeutic and immunotherapeutic effects by oxidative stress and apoptotic cell death. Magnetite nanoparticles were conjugated with NPrCAP to introduce thermotherapeutic and immunotherapeutic effects through nonapoptotic cell death and generation of heat shock protein (HSP) upon exposure to alternating magnetic field (AMF). During these therapeutic processes, NPrCAP was also expected to provide melanoma-targeted drug delivery system.

Ectopic expression of tyrosinase increases melanin synthesis and cell death following UVB irradiation in fibroblasts from familial atypical multiple mole and melanoma (FAMMM) patients.

Patients with familial atypical multiple mole and melanoma (FAMMM) [so-called familial dysplastic naevus syndrome (FDNS)] have a high risk for the development of malignant melanoma. The underlying gene defect has an autosomal dominant inheritance with variable expression and incomplete penetrance. Fibroblasts derived from FAMMM patients have high sensitivity to UVC and mutagens, e.g. 4-nitroquinoline-1-oxide. We were interested in identifying how the combination of inherent sensitivity to UV light and abnormal melanin synthesis interacts in the development of melanoma in FAMMM patients. Intermediates of melanin synthesis produce free radicals that are toxic to cells. Atypical moles (dysplastic naevi) are engaged in the biosynthesis of abnormal melanin pigments. This study examined whether there was any abnormal melanin pigmentation or cell damage after the ectopic expression of tyrosinase in fibroblasts from FAMMM patients when compared with fibroblasts from normal subjects. Fibroblasts from FAMMM patients (3012T and 3072T) were associated with a higher sensitivity than normal human fibroblasts to the toxicity of UVB. When cells were infected with tyrosinase-expressing adenovirus (Ad-HT) and irradiated with UVB, FAMMM fibroblasts showed higher tyrosinase activity, produced more melanin pigments and were degraded more significantly than normal human fibroblasts. Western blot analysis revealed that Ad-HT-infected 3072T produced a larger amount of tyrosinase protein than did Ad-HT-infected normal fibroblasts after UVB irradiation. Our findings suggest: (1) that FAMMM fibroblasts have an unknown machinery which enhances tyrosinase expression by UVB irradiation; and (2) that the resulting increase in melanin synthesis affects the cytotoxicity of UVB to FAMMM fibroblasts. All of these processes may be involved in the genomic instability and development of melanoma in FAMMM patients.

Imiquimod 5% cream as a therapeutic option for extramammary Paget's disease

A wide local excision is the standard treatment for extramammary Pagets disease (EMPD), though this treatment often leads to permanent anogenital mutilation and functional impairment. The purpose of our study is to evaluate the efficacy and safety of the topical application of imiquimod 5% cream for non‐invasive EMPD. We examined nine patients with EMPD. Eight of the nine patients were treated with imiquimod 5% cream three times per week for 16 weeks; one case was treated for 6 weeks. The response rate was 100% including five complete remissions. Local irritation was observed in three patients, which was controlled by a provisional withdrawal of the treatment. These results suggest that imiquimod 5% cream may be considered an alternative therapeutic option for the treatment of non‐invasive EMPD.