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Paulownin, a natural compound derived from Paulownia tomentosa wood, exhibits various physiological functions, including anti-bacterial and anti-fungal effects. However, the impact of paulownin on natural killer (NK) cell immune activity remains largely unknown. In this study, we investigated the effect of paulownin on NK cell activity both in vitro and in vivo, and explored its potential mechanisms. NK-92 cells were used for in vitro experiments and a BALB/c mouse model with B16F10 cells injected subcutaneously were used for in vivo anti-tumor analysis. We found that paulownin enhanced the cytolytic activity of NK-92 cells against leukemia, human colon, and human lung cancer cell lines. Paulownin treatment increased the expression of the degranulation marker protein CD107a and cytolytic granules, including granzyme B and perforin in NK-92 cells. Moreover, these enhancements of cytotoxicity and the expression of cytolytic granules induced by paulownin were also observed in human primary NK cells. Signaling studies showed that paulownin promoted the phosphorylation of JNK. The increased perforin expression and elevated cytotoxic activity induced by paulownin were effectively inhibited by pre-treatment with a JNK inhibitor. In vivo studies demonstrated that the administration of paulownin suppressed the growth of B16F10 melanoma cells allografted into mice. Paulownin administration promoted the activation of NK cells in the spleen of mice, resulting in enhanced cytotoxicity against YAC-1 cells. Moreover, the antitumor effects of paulownin were reduced upon the depletion of NK cells. Therefore, these results suggest that paulownin enhances NK cell cytotoxicity by activating the JNK signaling pathway and provide significant implications for developing new strategies for cancer immunotherapy. [ABSTRACT FROM AUTHOR]

Skin cancer is the most common type of cancer. The incidence rate of skin cancer has continuously increased over the past decades. In an effort to discover novel anticancer agents, we identified a novel tubulin inhibitor STK899704, which is structurally distinct from other microtubule-binding agents such as colchicine, vinca alkaloids and taxanes. STK899704 inhibited microtubule polymerization leading to mitotic arrest and suppressed the proliferation of various cancer cell lines as well as multidrug resistance cancer cell lines. In this study, our investigation is further extended into animal model to evaluate the effect of STK899704 on skin carcinogenesis in vivo. Surprisingly, almost 80% of the tumors treated with STK899704 were regressed with a one-fifth reduction in tumor volume. Furthermore, the efficacy of STK899704 was nearly 2 times higher than that of 5-fluorouracil, a widely used skin cancer therapeutic. Overall, our results suggest that STK899704 is a promising anticancer chemotherapeutic that may replace existing therapies, particularly for skin cancer. [ABSTRACT FROM AUTHOR]

Healthy expansion of adipose tissue maintains metabolic homeostasis by storing excess chemical energy in increased fat mass. The STAT5-PPAR gamma pathway reportedly regulates adipocyte differentiation, lipid metabolism and adipogenesis. Ginsenoside Rg3 is one of the diverse groups of steroidal saponins, the major active components of ginseng, which have demonstrated pharmacological properties. In this study, we evaluated the therapeutic effects of ginsenoside Rg3 under pathological conditions in vitro and in vivo. We examined the effects of ginsenoside Rg3 on glucose level, insulin sensitivity and lipogenesis in high-fat diet-fed C57BL/6 mice. Ginsenoside Rg3 was also applied to the pre-adipocyte cell line 3T3-L1 to assess the impact on lipogenesis. Ginsenoside Rg3 reduced epididymal white adipose tissue (eWAT) size and hepatic steatosis, and the amount of triglycerides (TGs) in both eWAT and liver. Similar to the murine model, Rg3-treated 3T3-L1 cells showed a reduction in lipid accumulation and amount of total TGs. Ginsenoside Rg3 regulates the expression of PPAR gamma though STAT5 in vitro and in vivo. According to our results, lipid metabolism-related genes were downregulated in the high-fat mice and 3T3-L1 cell line. Rg3 shows potential for the amelioration of obesity-induced pathology, acting though STAT5-PPAR gamma to facilitate the healthy functioning of adipose tissue. This is the first report of evidence that obesity-induced insulin resistance and lipotoxicity can be treated with ginsenoside Rg3, which acts though the STAT5-PPAR gamma pathway in vivo and in vitro. [ABSTRACT FROM AUTHOR]

STUDY QUESTION: Is the decreased natural killer (NK) cell cytolytic activity in the peritoneal fluid (PF) of endometriosis patients due to primary cytokine activity? SUMMARY ANSWER: An increased level of interleukin-6 (IL-6) in the PF of patients with endometriosis suppresses NK cell cytolytic activity by down-regulating cytolytic granule components, such as granzyme B and perforin, through the modulation of Src homology region 2-containing protein tyrosine phosphatase-2 (SHP-2) expression. WHAT IS ALREADY KNOWN: Endometriosis is known to be related to a defect in NK cell cytolytic activity. Additionally, the levels of inflammatory cytokines are elevated in the PF of women with endometriosis. STUDY DESIGN, SIZE, DURATION: The effects of PF on the differentiation and functional activity of NK cells were investigated in patients with or without endometriosis, and cytokines that reduce NK cell cytolytic activity in endometriosis patients were examined. The study included women who underwent laparoscopic examination for the diagnosis of endometriosis from August 2012 to July 2013 (33 women with, and 15 women without, endometriosis). PARTICIPANTS/MATERIALS, SETTING, METHODS: Women of reproductive age (20â€"40 years old) who underwent laparoscopic examination for endometriosis were included. Cytokines present in the PF were identified by enzyme-linked immunosorbent assay. The cytolytic activity of NK cells in the PF was also analyzed using a calcein-acetoxy methyl ester (AM) release assay. MAIN RESULTS AND THE ROLE OF CHANCE PF: from patients with endometriosis suppressed the differentiation and cytotoxicity of NK cells compared with PF from controls (P < 0.05). Increased levels of IL-6 were also found in the PF of patients with endometriosis (P < 0.01), and IL-6 levels were negatively correlated with the cytolytic activity of NK cells (rs = â'0.558, P = 0.03). Furthermore, IL-6 reduced the cytolytic activity of NK cells, concomitantly with the down-regulation of granzyme B and perforin (P < 0.05), by modulating SHP-2. Importantly, the addition of anti-IL-6 to the PF of endometriosis patients restored the activity of NK cells (P < 0.01), suggesting that IL-6 plays a crucial role in the reduction of NK cell activity in the PF of patients with endometriosis. LIMITATIONS, REASONS FOR CAUTION PF: contains various inflammatory cytokines in addition to IL-6 and so it is possible that other cytokines may affect the differentiation and activity of NK cells. WIDER IMPLICATIONS OF THE FINDINGS: Our results imply that the suppression of IL-6 using an anti-IL-6 antibody or soluble IL-6 receptor could rescue the impairment of NK cell activity in patients with endometriosis. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the KRIBB Creative Research Program (KCS3051312); the STP project (DTM0111221) of the Ministry of Knowledge & Economy and the Basic Science Research Program (RBM0271312) of the National Research Foundation of Korea (NRF) from the Ministry of Education, Science & Technology. There are no conflicts of interest. [ABSTRACT FROM AUTHOR]

BACKGROUND: Kallikrein-related peptidase 6 (KLK6) encodes a trypsin-like serine protease that is up-regulated in several cancers, although the putative functions of KLK6 in cancer have not been elucidated. In the current study, overexpression of KLK6 was identified in colon cancer, and the possibility that KLK6 may be a suitable candidate as a tumor marker was examined. METHODS: Messenger RNA (mRNA) transcript levels and protein up-regulation of KLK6 in colon cancer tissues was examined using reverse transcriptase-polymerase chain reaction, immunohistochemistry, and clinicopathologic analyses. Cell proliferation, invasiveness, and antiapoptotic activity were determined in colon cancer cells that were transfected with small-interfering RNA (siRNA) of KLK6. RESULTS: KLK6 mRNA was up-regulated significantly in tumor tissues compared with nontumor regions. KLK6 protein was strongly expressed in adenocarcinomas but was not expressed in normal mucosa or in premalignant dysplastic lesions. Sera from patients with colon cancer revealed an increase in KLK6 secretion (0.25 lg/mL; P = .031) compared with noncancer cells (0.19 µg/mL). Clinicopathologic and immunohistochemical studies of 143 patients with colon cancer revealed a significant correlation between KLK6 expression and Dukes disease stage (P = .005). High KLK6 expression was associated significantly with shorter overall (P = .001) and recurrence-free survival (P = .001). The rates of proliferation and invasiveness were decreased by 50% in cells that were transfected with KLK6 siRNA. The overexpression of KLK6 led to decreased activity of the E-cadherin promoter. CONCLUSIONS: KLK6 was up-regulated significantly in tissues and sera from patients with colon cancer and was associated closely with a poor prognosis, suggesting that KLK6 may be used as a potential biomarker and a therapeutic target for colon cancer. [ABSTRACT FROM AUTHOR]

E-cadherin, as a tumor suppressor, plays an important role for intercellular adhesion involved in metastasis. Although K-Ras is highly expressed in a variety of cancers, the regulation of E-cadherin expression by K-Ras in association with DNA methylation and cell metastasis has not been completely clarified. In this study, E-cadherin expression was repressed in 267B1/K-Ras human epithelial prostate cancer cells stably overexpressing K-Ras, resulting from hypermethylation of E-cadherin promoter as evidenced by methylation-specific polymerase chain reaction (PCR), bisulfite sequencing, real-time reverse transcription–PCR and western blot analysis. The increased level of DNA methyltransferase (DNMT) 3b in 267B1/K-Ras cells was reduced by small interfering RNA-mediated knockdown of k-ras, whereas DNMT1 and DNMT3a did not change regardless of K-Ras or 5-aza-2′-deoxycytidine (5′-AzaC) treatment. Furthermore, binding of DNMT3b to E-cadherin promoter was increased in 267B1/K-Ras cells but was reduced by 5′-AzaC, as revealed by chromatin immunoprecipitation assay, which was in agreement with cell aggregation and invasive mobilization of the cells. Hence, our data suggest that increased binding of DNMT3b to E-cadherin promoter region by K-Ras cause promoter hypermethylation for reduced expression of E-cadherin, leading to the decreased cell aggregation and increased metastasis of human prostate cancer cells overexpressing K-Ras. [ABSTRACT FROM PUBLISHER]

CKS2 was identified as an upregulated gene in gastric cancer via our DNA microarray. This study was to verify the upregulation of CKS2 in many gastric cancer patients and to examine the CKS2-mediated cellular response. CKS2 upregulation was analyzed using reverse transcriptase PCR, real-time PCR, and immunohistochemical and clinicopathological analyses. GFP-CKS2 or CKS2-siRNA was used to analyze the cellular localization and proliferation. The strong upregulation of mRNA and protein levels of CKS2 was identified. In CKS2-overexpressing cells, tumor suppressor p53 and p21cip1 were downregulated and cell growth was increased. In contrast, CKS2-siRNA-transfected cells showed an increased tumor suppressor expression and decreased cell growth. We showed that CKS2 was significantly upregulated in gastric cancers and a high level of CKS2 was highly correlated with histologic tumor differentiation and pathological grade of the tumor size, lymph node, and metastasis stage. We suggest that the cell cycle regulator CKS2 might be deeply involved in gastric cancer progression. [ABSTRACT FROM AUTHOR]

NDRG2 (N-myc downstream-regulated gene 2) is a candidate tumor suppressor implicated in control of glioblastoma proliferation and dendritic cell differentiation. The microphthalmia-associated transcription factor (Mitf) plays a crucial role in the melanocyte lineage and in melanoma by controlling survival, differentiation, cell cycle entry and exit, and melanoma metastasis. Identifying upstream regulators of Mitf expression, therefore, remains a key issue. In this study, we aimed to assess whether the candidate tumor suppressor NDRG2 can modulate Mitf expression. Here, we show that NDRG2 acts to prevent cAMP and β-catenin-mediated activation of the Mitf promoter, thereby blocking melanogenesis via the downstream Mitf target genes Tyrosinase, Tyrp1 and Dct. The data suggest that NDRG2 impairs melanogenesis by interfering with both the TCF/β-catenin and cAMP/CREB pathways that are known to stimulate Mitf expression in melanocytes and have major implications for the role of NDRG2 in pigmentation and melanoma progression. Taken together, the results not only identify NDRG2 as a novel regulator of pigmentation, but also potentially a key factor in regulating melanoma progression via Mitf. [ABSTRACT FROM AUTHOR]