Feeding a High-Fat Diet for a Limited Duration Increases Cancer Incidence in a Breast Cancer Model.

High-fat intake by young Asian women impacts the risk of breast cancer. Understanding the underlying molecular mechanisms may be essential for disease prevention in Asia as well as globally. We aimed to examine the effects of corn oil- and animal fat-based high-fat diets (32.9 and 31.4%, respectively, of fat energy ratio as compared to 12.3% in the standard diet) on mammary carcinogenesis and alterations in gene expression and epigenetic statuses in the mammary gland during the growth stages in a rat model. An increased incidence of carcinomas was observed after the cessation of high-fat feeding. In addition, rapid tumor growth and elevations in Celsr2 expression, which may be a result of DNA hypomethylation patterns in the 3' untranslated region of the gene were noted in the animal fat group. In the human breast carcinoma cell line MCF7, a marginal decrease in cell viability was observed following the knockdown of Celsr2, suggesting that the animal fat-associated risk of cancer is partly due to the deregulation of mammary cell proliferation via non-metabolic gene functions. The present results will contribute to the development of strategies for controlling the food-associated risk of breast cancer, particularly in younger age groups.

A Marine Carotenoid of Fucoxanthinol Accelerates the Growth of Human Pancreatic Cancer PANC-1 Cells.

Fucoxanthin and its metabolite fucoxanthinol (FxOH), highly polar xanthophylls, exert strong anticancer effects against many cancer cell types. However, the effects of Fx and FxOH on pancreatic cancer, a high mortality cancer, remain unclear. We herein investigated whether FxOH induces apoptosis in human pancreatic cancer cells. FxOH (5.0 µmol/L) significantly promoted the growth of human pancreatic cancer PANC-1 cells, but induced apoptosis in human colorectal cancer DLD-1 cells. A microarray-based gene analysis revealed that the gene sets of cell cycle, adhesion, PI3K/AKT, MAPK, NRF2, adipogenesis, TGF-ß, STAT, and Wnt signals in PANC-1 cells were markedly altered by FxOH. A western blot analysis showed that FxOH up-regulated the expression of integrin ß1 and PPARγ as well as the activation of pFAK(Tyr397), pPaxillin(Tyr31), and pAKT(Ser473) in PANC-1 cells, but exerted the opposite effects in DLD-1 cells. Moreover, the expression of FYN, a downstream target of integrin subunits, was up-regulated (7.4-fold by qPCR) in FxOH-treated PANC-1 cells. These results suggest that FxOH accelerates the growth of PANC-1 cells by up-regulating the expression of integrin ß1, FAK, Paxillin, FYN, AKT, and PPARγ.

Characterization of the large-scale Japanese patient-derived xenograft (J-PDX) library.

The use of patient-derived xenografts (PDXs) has recently attracted attention as a drug discovery platform with a high predictive clinical efficacy and a preserved tumor heterogeneity. Given the racial differences in genetic variations, it would be desirable to establish a PDX library from Japanese cancer patients on a large scale. We thus tried to construct the Japanese PDX (J-PDX) library with a detailed clinical information for further clinical utilization. Between August 2018 and May 2020, a total of 1126 cancer specimens from 1079 patients were obtained at the National Cancer Center Hospital and National Cancer Center Hospital East, Japan, and were immediately transplanted to immunodeficient mice at the National Cancer Center Research Institute. A total of 298 cross-cancer PDXs were successfully established. The time to engraftment varied greatly by cancer subtypes, especially in the first passage. The engraftment rate was strongly affected by the clinical stage and survival time of the original patients. Approximately 1 year was needed from tumor collection to the time when coclinical trials were conducted to test the clinical utility. The 1-year survival rates of the patients who were involved in establishing the PDX differed significantly, from 95.6% for colorectal cancer to 56.3% for lung cancer. The J-PDX library consisting of a wide range of cancer subtypes has been successfully established as a platform for drug discovery and development in Japan. When conducting coclinical trials, it is necessary to consider the target cancer type, stage, and engraftment rate in light of this report.

Identification of three closely linked loci conferring broad-spectrum Phytophthora sojae resistance in soybean variety Tosan-231.

KEY MESSAGE: A variable genomic region containing two Harosoy-derived loci related to Rps7 and one Nemashirazu-derived locus confers broad-spectrum Phytophthora sojae resistance in Tosan-231 and is useful for developing resistant cultivars. We investigated resistance to pathotypically variable Phytophthora sojae isolates in the soybean variety Tosan-231, which has broad-spectrum resistance. Mapping analysis using descendent lines from a cross between Shuurei and Tosan-231 demonstrated that a genomic region between SSR markers BARCSOYSSR_03_0209 and BARCSOYSSR_03_0385 (termed "Region T"), confers broad-spectrum resistance in Tosan-231 and contains three closely linked resistance loci. Inoculation tests with 20 P. sojae isolates of different pathotypes and simple sequence repeat (SSR) analysis of progenitors of Tosan-231 facilitated identification and characterization of Rps genes at the three resistance loci. Two resistance genes, RpsT1 and RpsT2, were found to be derived from Harosoy carrying Rps7. This result suggested two mutually exclusive possibilities: (1) either RpsT1 or RpsT2 is Rps7, and the other is a locally functional novel gene; (2) Rps7 is not a single gene but in fact comprises RpsT1 and RpsT2. The resistance locus containing RpsT3 is derived from Nemashirazu, in which Rps genes have remained poorly defined. Moreover, we identified two genomic regions with relatively high recombination frequencies on the basis of mapping information and proposed a strategy to readily assemble useful resistance genes in or around Region T.

Fucoxanthin Prevents Pancreatic Tumorigenesis in C57BL/6J Mice That Received Allogenic and Orthotopic Transplants of Cancer Cells.

Fucoxanthin (Fx) is a marine carotenoid with anti-inflammatory and anti-cancer properties in various animal models of carcinogenesis. However, there is currently no information on the effects of Fx in animal models of pancreatic cancer. We investigated the chemopreventive effects of Fx in C57BL/6J mice that received allogenic and orthotopic transplantations of cancer cells (KMPC44) derived from a pancreatic cancer murine model (Ptf1aCre/+; LSL-krasG12D/+). Using microarray, immunofluorescence, western blot, and siRNA analyses, alterations in cancer-related genes and protein expression were evaluated in pancreatic tumors of Fx-administered mice. Fx administration prevented the adenocarcinoma (ADC) development of pancreatic and parietal peritoneum tissues in a pancreatic cancer murine model, but not the incidence of ADC. Gene and protein expressions showed that the suppression of chemokine (C-C motif) ligand 21 (CCL21)/chemokine receptor 7 (CCR7) axis, its downstream of Rho A, B- and T-lymphocyte attenuator (BTLA), N-cadherin, αSMA, pFAK(Tyr397), and pPaxillin(Tyr31) were significantly suppressed in the pancreatic tumors of mice treated with Fx. In addition, Ccr7 knockdown significantly attenuated the growth of KMPC44 cells. These results suggest that Fx is a promising candidate for pancreatic cancer chemoprevention that mediates the suppression of the CCL21/CCR7 axis, BTLA, tumor microenvironment, epithelial mesenchymal transition, and adhesion.

[Possibility of Pancreatic Cancer Chemoprevention by Anti-Inflammatory/Anti-Diabetic/Anti-Dyslipidemic Drugs].

Pancreatic cancer death is increasing with aging of population. Cancer prevention is quite important especially for intractable cancers such as pancreatic cancer. Epidemiological studies have suggested that cigarette smoking, heavy alcohol drinking, chronic pancreatitis, obesity, type 2 diabetes mellitus and family history are risk factors for pancreatic cancer. Fatty pancreas is also a possible risk factor. Therefore, in addition to stop of smoking, improvement of these inflammatory conditions by changing life styles and/or taking medicines is considered to be helpful to prevent pancreatic cancer development. In this article, as candidate chemopreventive agents for pancreatic cancer, anti-inflammatory drugs, anti-diabetic drugs and anti- dyslipidemic drugs are focused on, and the effects of these drugs on pancreatic cancer in humans and experimental animals are described.

Establishment and characterization of patient-derived cancer models of malignant peripheral nerve sheath tumors.

BACKGROUND: Malignant peripheral nerve sheath tumors (MPNSTs) are a rare subtype of soft-tissue sarcoma, derived from a peripheral branch or the sheath of the sciatic nerve, brachial plexus, or sacral plexus. The clinical outcomes for MPNST patients with unresectable or metastatic tumors are dismal, and novel therapeutic strategies are required. Although patient-derived cancer cell lines are vital for basic research and preclinical studies, few MPNST cell lines are available from public cell banks. Therefore, the aim of this study was to establish cancer cell lines derived from MPNST patients. METHODS: We used tumor tissues from five patients with MPNSTs, including one derived from a rare bone tissue MPNST. The tumor tissues were obtained at the time of surgery and were immediately processed to establish cell lines. A patient-derived xenograft was also established when a sufficient amount of tumor tissue was available. The characterization of established cells was performed with respect to cell proliferation, spheroid formation, and invasion. The mutation status of actionable genes was monitored by NCC Oncopanel, by which the mutation of 114 genes was assessed by next-generation sequencing. The response to anti-cancer agents, including anti-cancer drugs approved for the treatment of other malignancies was investigated in the established cell lines. RESULTS: We established five cell lines (NCC-MPNST1-C1, NCC-MPNST2-C1, NCC-MPNST3-C1, NCC-MPNST4-C1, and NCC-MPNST5-C1) from the original tumors, and also established patient-derived xenografts (PDXs) from which one cell line (NCC-MPNST3-X2-C1) was produced. The established MPNST cell lines proliferated continuously and formed spheroids while exhibiting distinct invasion abilities. The cell lines had typical mutations in the actionable genes, and the mutation profiles differed among the cell lines. The responsiveness to examined anti-cancer agents differed among cell lines; while the presence of an actionable gene mutation did not correspond with the response to the anticipated anti-cancer agents. CONCLUSION: The established cell lines exhibit various characteristics, including proliferation and invasion potential. In addition, they had different mutation profiles and response to the anti-cancer agents. These observations suggest that the established cell lines will be useful for future research on MPNSTs.

A yolk sac tumor of the pancreas and derived xenograft model effectively responded to VIP chemotherapy.

BACKGROUND: Yolk sac tumors (YSTs) of the pancreas are extremely rare, and no drug responsiveness data are available regarding YSTs. METHODS: We report a pancreatic YST in a 70-year-old woman, and its chemotherapeutic responsiveness based on clinical records and evaluation of a patient-derived xenograft (PDX) line of the YST. RESULTS: The YST was an 11-cm, solid mass located in the pancreatic tail. Histologically, the tumor showed medullary proliferation of tumor cells, with a variety of growth patterns including microcystic/reticular, endodermal sinus, and hepatoid patterns. Immunohistochemically, the tumor cells were positive for Sall4, glypican-3, and alpha-fetoprotein. We administered VIP (etoposide, ifosfamide, cisplatin) chemotherapy for a recurrent liver tumor, and obtained complete pathological remission. A drug-response assay using the PDX line from this YST revealed that both VIP and gemcitabine effectively inhibit tumor growth. CONCLUSIONS: These results suggest that differential diagnosis of YST from adenocarcinoma is important for selecting appropriate chemotherapy.

Fatty pancreas: A possible risk factor for pancreatic cancer in animals and humans.

Obesity, type 2 diabetes mellitus (T2DM) and aging are associated with pancreatic cancer risk, but the mechanisms of pancreatic cancer development caused by these factors are not clearly understood. Syrian golden hamsters are susceptible to N-nitrosobis(2-oxopropyl)amine (BOP)-induced pancreatic carcinogenesis. Aging, BOP treatment and/or a high-fat diet cause severe and scattered fatty infiltration (FI) of the pancreas with abnormal adipokine production and promote pancreatic ductal adenocarcinoma (PDAC) development. The KK-Ay mouse, a T2DM model, also develops severe and scattered FI of the pancreas. Treatment with BOP induced significantly higher cell proliferation in the pancreatic ducts of KK-Ay mice, but not in those of ICR and C57BL/6J mice, both of which are characterized by an absence of scattered FI. Thus, we hypothesized that severely scattered FI may be involved in the susceptibility to PDAC development. Indeed, severe pancreatic FI, or fatty pancreas, is observed in humans and is associated with age, body mass index (BMI) and DM, which are risk factors for pancreatic cancer. We analyzed the degree of FI in the non-cancerous parts of PDAC and non-PDAC patients who had undergone pancreatoduodenectomy by histopathology and demonstrated that the degree of pancreatic FI in PDAC cases is significantly higher than that in non-PDAC controls. Moreover, the association with PDAC is positive, even after adjusting for BMI and the prevalence of DM. Accumulating evidence suggests that pancreatic FI is involved in PDAC development in animals and humans, and further investigations to clarify the genetic and environmental factors that cause pancreatic FI are warranted.

Establishment and proteomic characterization of NCC-LMS1-C1, a novel cell line of primary leiomyosarcoma of the bone.

BACKGROUND: Leiomyosarcoma (LMS) is one of most aggressive mesenchymal malignancies that differentiate towards smooth muscle. The clinical outcome of LMS patients is poor; as such, there is an urgent need for novel therapeutic approaches. Experimental models such as patient-derived cell lines are invaluable tools for pre-clinical studies. In the present study, we established a stable cell line from the tumor tissue of a patient with a primary LMS of the bone. Despite the urgent need for novel therapeutic strategies in LMS, there are only a few LMS cell lines available in public cell banks, none of which are primary to the bone. METHODS: Bone primary LMS tumor tissues were sampled to establish cell lines. Morphological and proteomic analyses were performed and sensitivity to pazopanib was evaluated. RESULTS: NCC-LMS1-C1 cells were maintained for over 100 passages. The cells exhibited a spindle shape and aggressive growth; they also expressed smooth muscle actin, reflecting the original LMS tissue (i.e. smooth muscle cells). The cells also showed tumor characteristics such as colony formation on soft agar and sensitivity to pazopanib, doxorubicin and cisplatin, with half-maximal inhibitory concentrations of 4.5, 0.11 and 20 µM, respectively. Proteomic analyses by mass spectrometry and antibody array revealed some differences in the protein expression profiles of these cells as compared to the original tumor tissue. CONCLUSIONS: Our results indicate that the NCC-LMS1-C1 cell lines will be useful for LMS research.

Evaluation of Resistance to Phytophthora sojae in Soybean Mini Core Collections Using an Improved Assay System.

Stem and root rot disease caused by Phytophthora sojae is devastating to soybean crops worldwide. Developing host resistance to P. sojae, considered the most effective and stable means to control this disease, is partly hampered by limited germplasm resources. In this study, we first modified conventional methods for a P. sojae resistance assay to a simpler and more cost-effective version, in which the P. sojae inoculum was mixed into the soil and the resistance was evaluated by survival rate (%) of soybean seedlings. This rating had significant correlations (P < 0.01) with the reduction in root fresh weight and the visual root rot severity. Applying this method to evaluate P. sojae resistance in soybean mini core collections comprising either 79 accessions originating from Japan (JMC) or 80 accessions collected around the world (WMC) revealed a wide variation in resistance among the individual varieties. In total, 38 accessions from the JMC and 41 from the WMC exhibited resistance or moderate resistance to P. sojae isolate N1 (with virulence to Rps1b, 3c, 4, 5, and 6), with ≥50% survival. Of these, 26 from the JMC and 29 from the WMC showed at least moderate resistance to P. sojae isolate HR1 (vir Rps1a-c, 1k, 2, 3a-c, 4-6, and 8). Additionally, 24 WCS accessions, in contrast to only 6 from the JMC, exhibited 100% survival after being challenged with both the N1 and HR1 isolates, suggesting a biogeographical difference between the two collections. We further verified two JMC varieties, Daizu and Amagi zairai 90D, for their resistance to an additional four P. sojae isolates (60 to 100% survival), which may provide new and valuable genetic sources for P. sojae resistance breeding in soybean.

Extracts of black and brown rice powders improve hepatic lipid accumulation via the activation of PPARα in obese and diabetic model mice.

Rice powder extract (RPE) from black and brown rice (Oryza sativa L. indica) improves hepatic lipid accumulation in obese and diabetic model mice via peroxisomal fatty acid oxidation. RPE showed PPARα agonistic activity which did not differ between black and brown RPE despite a higher anthocyanin content in black RPE.

Osteopontin Deficiency Suppresses Intestinal Tumor Development in Apc-Deficient Min Mice.

Osteopontin (OPN) is a secreted phosphoglycoprotein, and is a transcriptional target of aberrant Wnt signaling. OPN is upregulated in human colon cancers, and is suggested to enhance cancer progression. In this study, the effect of deficiency of OPN on intestinal tumor development in Apc-deficient Min mice was investigated. At 16 weeks of age, the number of small intestinal polyps in Min/OPN(+/-) and Min/OPN(-/-) mice was lower than that of Min/OPN(+/+) mice. Colorectal tumor incidences and multiplicities in Min/OPN(+/-) and Min/OPN(-/-) mice were significantly lower than those in Min/OPN(+/+) mice, being 48% and 0.6 ± 0.8, 50% and 0.8 ± 0.9 vs. 80% and 1.6 ± 1.7, respectively. OPN expression in colorectal tumors was strongly upregulated in Min/OPN(+/+) compared to adjacent non-tumor parts, but was decreased in Min/OPN(+/-) and not detected in Min/OPN(-/-). Targets of OPN, matrix metalloproteinases (MMPs)-3, -9, and -13 were lowered by OPN deficiency. Macrophage marker F4/80 in colorectal tumors was also lowered by OPN deficiency. MMP-9 expression was observed in tumor cells and tumor-infiltrating neutrophils. These results indicate that induction of OPN by aberrant Wnt signaling could enhance colorectal tumor development in part by upregulation of MMP-3, -9, and -13 and infiltration of macrophage and neutrophils. Suppression of OPN expression could contribute to tumor prevention, but complete deficiency of OPN may cause some adverse effects.

Liquid-Phase Synthesis of Ba2V2O7 Phosphor Powders and Films Using Immiscible Biphasic Organic-Aqueous Systems.

A liquid-phase synthesis of inorganic phosphor materials at a moderate temperature was proposed by using immiscible liquid-liquid biphasic systems. A self-activated Ba2V2O7 phosphor was actually synthesized from vanadium alkoxide dissolved in an organic solution and barium acetate in an aqueous solution. A mild hydrolysis reaction of the alkoxide started at the organic-inorganic interface, and an intermediate compound, Ba(VO3)2·H2O, was initially formed. Ba2V2O7 powders were then obtained by the conversion from Ba(VO3)2·H2O promoted in the aqueous solution. Ba2V2O7 films were obtained on surface-modified silica glass substrates through the similar chemical reactions. Factors such as the surface state of substrates, the kind of organic solvents, and the volume of aqueous solutions were examined to improve the film deposition behavior. The resultant Ba2V2O7 materials showed broad-band visible photoluminescence upon irradiation with ultraviolet light based on the charge transfer transition in the VO4(3-) units existing as dimers.

Associations between polymorphisms in folate-metabolizing genes and pancreatic cancer risk in Japanese subjects.

BACKGROUND: Evidence supporting the associations between folate metabolizing gene polymorphisms and pancreatic cancer has been inconclusive. We examined their associations in a case-control study of Japanese subjects. METHODS: Our case-control study involved 360 newly diagnosed pancreatic cancer cases and 400 frequency-matched, non-cancer control subjects. We genotyped four folate metabolizing gene polymorphisms, including two polymorphisms (rs1801133 and rs1801131) in the methylenetetrahydrofolate (MTHFR) gene, one polymorphism (rs1801394) in the 5-methyltetrahydrofolate-homocysteine methyltransferase reductase (MTRR) gene and one polymorphism (rs1805087) in the 5-methyltetrahydrofolate-homocysteine methyltransferase (MTR) gene. Genotyping was performed using Fluidigm SNPtype assays. Unconditional logistic regression methods were used to estimate odds ratios (ORs) and 95 % confidence intervals (CIs) for the associations between folate metabolizing gene variants and pancreatic cancer risk. RESULTS: Overall we did not observe a significant association between these four genotypes and pancreatic cancer risk. For rs1801133, compared with individuals with the CC genotype of MTHFR C677T, the OR for those with the CT genotype and TT genotype was 0.87 (0.62-1.22) and 0.99 (0.65-1.51), respectively. For rs1801131, individuals with the CC genotype had approximately 1.2-fold increased risk compared with those with the AA genotype, but the association was not statistically significant. In analyses stratified by smoking and drinking status, no significant associations were noted for C677T genotypes. No significant interactions were observed with smoking and drinking with respect to pancreatic cancer risk. CONCLUSIONS: Our data did not support the hypothesis that MTHFR polymorphisms or other polymorphisms in the folate metabolizing pathway are associated with pancreatic cancer risk.

Genetic reconstitution of tumorigenesis in primary intestinal cells.

Animal models for human colorectal cancer recapitulate multistep carcinogenesis that is typically initiated by activation of the Wnt pathway. Although potential roles of both genetic and environmental modifiers have been extensively investigated in vivo, it remains elusive whether epithelial cells definitely require interaction with stromal cells or microflora for tumor development. Here we show that tumor development could be simply induced independently of intestinal microenvironment, even with WT murine primary intestinal cells alone. We developed an efficient method for lentiviral transduction of intestinal organoids in 3D culture. Despite seemingly antiproliferative effects by knockdown of adenomatous polyposis coli (APC), we managed to reproducibly induce APC-inactivated intestinal organoids. As predicted, these organoids were constitutively active in the Wnt signaling pathway and proved tumorigenic when injected into nude mice, yielding highly proliferative tubular epithelial glands accompanied by prominent stromal tissue. Consistent with cellular transformation, tumor-derived epithelial cells acquired sphere formation potential, gave rise to secondary tumors on retransplantation, and highly expressed cancer stem cell markers. Inactivation of p53 or phosphatase and tensin homolog deleted from chromosome 10, or activation of Kras, promoted tumor development only in the context of APC suppression, consistent with earlier genetic studies. These findings clearly indicated that genetic cooperation for intestinal tumorigenesis could be essentially recapitulated in intestinal organoids without generating gene-modified mice. Taken together, this in vitro model for colon cancer described herein could potentially provide unique opportunities for carcinogenesis studies by serving as a substitute or complement to the currently standard approaches.

Suppressive effects of the NADPH oxidase inhibitor apocynin on intestinal tumorigenesis in obese KK-A(y) and Apc mutant Min mice.

Obesity is a risk factor for colorectal cancer. The accumulation of abdominal fat tissue causes abundant reactive oxygen species production through the activation of NADPH oxidase due to excessive insulin stimulation. The enzyme NADPH oxidase catalyzes the production of reactive oxygen species and evokes the initiation and progression of tumorigenesis. Apocynin is an NADPH oxidase inhibitor that blocks the formation of the NADPH oxidase complex (active form). In this study, we investigated the effects of apocynin on the development of azoxymethane-induced colonic aberrant crypt foci in obese KK-A(y) mice and on the development of intestinal polyps in Apc mutant Min mice. Six-week-old KK-A(y) mice were injected with azoxymethane (200 µg/mouse once per week for 3 weeks) and given 250 mg/L apocynin or 500 mg/L apocynin in their drinking water for 7 weeks. Six-week-old Min mice were also treated with 500 mg/L apocynin for 6 weeks. Treatment with apocynin reduced the number of colorectal aberrant crypt foci in KK-A(y) mice by 21% and the number of intestinal polyps in Min mice by 40% compared with untreated mice. Both groups of mice tended to show improved oxidation of serum low-density lipoprotein and 8-oxo-2'-deoxyguanosine adducts in their adipose tissues. In addition, the inducible nitric oxide synthase mRNA levels in polyp tissues decreased. Moreover, apocynin was shown to suppress nuclear factor-κB transcriptional activity in vitro. These results suggest that apocynin and other NADPH oxidase inhibitors may be effective colorectal cancer chemopreventive agents.

Involvement of NADPH oxidases in suppression of cyclooxygenase-2 promoter-dependent transcriptional activities by sesamol.

Cyclooxygenase-2 (COX-2) has been shown to play an important role in colon carcinogenesis. Moreover, one of the components of reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, NADPH oxidase 1 (NOX1), dominantly expressed in the colon, is implicated in the pathogenesis of colon cancer. We have reported that sesamol, one of the lignans in sesame seeds, suppressed COX-2 gene transcriptional activity in human colon cancer cells, and also suppressed intestinal polyp formation in Apc-mutant mice. In the present study, we investigated the involvement of NADPH oxidase in the inhibition of COX-2 transcriptional activity by sesamol. We found that several NADPH oxidase inhibitors, such as apocynin, showed suppressive effects on COX-2 transcriptional activity. Moreover, sesamol significantly suppressed NOX1 mRNA levels in a dose-dependent manner. In addition, we demonstrated that knockdown of NOX1 successfully suppressed COX-2 transcriptional activity. These results suggest that inhibition of NADPH oxidase, especially NOX1, may be involved in the mechanism of the suppression of COX-2 transcriptional activity by sesamol.

Sesamol suppresses cyclooxygenase-2 transcriptional activity in colon cancer cells and modifies intestinal polyp development in Apc (Min/+) mice.

Excessive prostaglandin production by cyclooxygenase-2 in stromal and epithelial cells is a causative factor of colorectal carcinogenesis. Thus, compounds which inhibit cyclooxygenase-2 transcriptional activity in colon epithelial cells could be candidates for anti-carcinogenic agents. A cyclooxygenase-2 transcriptional activity in the human colon cancer cell line DLD-1 has been measured using a ß-galactosidase reporter gene system. Using this system, we demonstrated that the decrease in basal cyclooxygenase-2 transcriptional activities at 100 µM sesamol, one of the lignans in sesame seeds, was 50%. Other compounds in sesame seeds such as sesamin, sesamolin, ferulic acid, and syringic acid did not exhibit significant suppression of cyclooxygenase-2 transcriptional activity at up to 100 µM. In a following experiment, 6-week-old male Min mice, Apc-deficient mice, were divided into a non-treated and 500 ppm sesamol groups. At the age of 15 weeks, it was found that treatment with sesamol decreased the number of polyps in the middle part of small intestine to 66.1% of the untreated value. Moreover, sesamol suppressed cyclooxygenase-2 and cytosolic prostaglandin E2 synthase mRNA in the polyp parts. The present findings may demonstrate the novel anti-carcinogenetic property of sesamol, and imply that agents that can suppress cyclooxygenase-2 expression may be useful cancer chemopreventive agents.

Ay allele promotes azoxymethane-induced colorectal carcinogenesis by macrophage migration in hyperlipidemic/diabetic KK mice.

The incidence of colorectal cancer has been increasing and is associated with obesity and diabetes. We have found that type 2 diabetes model KK-Ay/TaJcl (KK-Ay) mice develop tumors within a short period after treatment with azoxymethane (AOM). However, factors that contribute to the promotion of carcinogenesis have not been clarified. Therefore, we looked at the genetic background of KK-Ay, including two genetic characteristics of KK/TaJcl (KK) mice and C57BL/6J-Ham-Ay/+ (Ay) mice, compared with other non-obese and non-diabetic mouse strains C57BL/6J and ICR, and induced colorectal premalignant lesions, aberrant crypt foci (ACF), and tumors using AOM (150 µg/mouse/week for 4 weeks and 200 µg/mouse/week for 6 weeks, respectively). The mice with a diabetes feature, KK-Ay and KK, developed significantly more ACF, 67 and 61 per mouse, respectively, whereas ICR, Ay, and C57BL/6J mice developed 42, 24, and 18 ACF/mouse, respectively, at 17 weeks of age. Serum insulin and triglyceride levels in KK-Ay and KK mice were quite high compared with other non-diabetic mouse strains. Interestingly, KK-Ay mice developed more colorectal tumors (2.7 ± 2.3 tumor/mouse) than KK mice (1.2 ± 1.1 tumor/mouse) at 25 weeks of age, in spite of similar diabetic conditions. The colon cancers that developed in both KK-Ay and KK mice showed similar activation of ß-catenin signaling. However, mRNA levels of inflammatory factors related to the activation of macrophages were significantly higher in colorectal cancer of KK-Ay mice than in KK. These data indicate that factors such as insulin resistance and dyslipidemia observed in obese and diabetic patients could be involved in susceptibility to colorectal carcinogenesis. In addition, increase of tumor-associated macrophages may play important roles in the stages of promotion of colorectal cancer.