DMBA Treatment Research Articles

Selective effects of whey protein concentrate on glutathione levels and apoptosis in rats with mammary tumors

Glutathione (GSH) plays an important role in antioxidant defense and regulation of apoptosis. GSH deficiency is related to many diseases, including cancer, and increased GSH levels in cancer cells are associated with chemotherapy resistance because of resistance to apoptosis. In this study, we investigated the effects of whey protein concentrate (WPC), a precursor of GSH, in rats with mammary tumors induced by treatment with 7,12-dimethylbenz(a)anthracene (DMBA). DMBA treatment results in cellular changes that mimic the initiation and promotion of carcinogenesis of breast tissue. We aimed to examine the possible preventive effects of diets containing whey protein on DMBA-induced mammary tumors in rats. The results indicate that WPC (0.334 g/kg) supplementation significantly increased the liver GSH levels by 92%, and were accompanied by low Bax/Bcl-2 ratio (from 5 to 3) and cleaved caspase-3/procaspase-3 ratio (from 2.4 to 1.2) in DMBA-treated rats. Furthermore, tumor GSH levels were decreased by 47% in WPC-supplemented rats, which resulted in increased Bax/Bcl-2 ratio (from 0.9 to 2) and cleaved caspase-3/procaspase-3 ratio (from 1.1 to 2.7). In conclusion, supplementation with WPC could selectively deplete tumor GSH levels and, therefore, WPC supplementation might be a promising strategy to overcome treatment resistance in cancer therapy.

DMBA acts on cumulus cells to desynchronize nuclear and cytoplasmic maturation of pig oocytes

As an environmental pollutant and carcinogen, 7,12-dimethylbenz[a]anthracene (DMBA) can destroy ovarian follicles at all developmental stages in rodents. However, the underlying molecular mechanism remains obscure. In the present study, we aim to address how DMBA affects the in vitro maturation and development of porcine oocytes. We discovered that for 20 μM DMBA-treated cumulus-oocyte complexes (COCs), the rate of oocyte germinal vesicle breakdown (GVBD) was significantly altered, and the extrusion rate of first polar body was increased. Moreover, oocytes from 20 μM DMBA-treated COCs had significant down-regulation of H3K9me3 and H3K27me3, up-regulation of H3K36me3, higher incidence of DNA double strand breaks (DSBs) and early apoptosis. In striking contrast, none of these changes happened to 20 μM DMBA-treated cumulus-denuded oocytes (CDOs). Furthermore, 20 μM DMBA treatment increased the reactive oxygen species (ROS) level, decreased mitochondrial membrane potential (Δ Ψm), and inhibited developmental competence for oocytes from both COC and CDO groups. Collectively, our data indicate DMBA could act on cumulus cells via the gap junction to disturb the synchronization of nuclear and ooplasmic maturation, and reduce the developmental competence of oocytes.

7,12-dimethylbenz(a)-anthracene (DMBA) & High Fat High Sugar Diet Decrease Physical Activity in Female Mice

BACKGROUND: Regular exercise has been shown to diminish the risk of certain cancers. DMBA, (7, 12-dimethylbenz(a)-anthracene) is a complete carcinogen that is used to induce tumors in mice. It has yet to be established whether DMBA has an effect on voluntary wheel running (WR) in mice, and whether these effects may be exacerbated via consumption of a high fat high sugar (HFHS) diet. PURPOSE: Determine if DMBA treatment altered voluntary WR in female SENCAR mice, and whether a HFHS diet exacerbated treatment effects on voluntary WR. METHODS: Offspring of SENCAR breeder pairs were weaned at 3 weeks (wks) of age onto either an ad lib fed HFHS (20% protein, 45% fat/24% sucrose + 10% fructose water) or a diet restricted (DR) (12% kcal restriction, 20% protein, 10% fat, 57% cornstarch) diet. Animals were double-housed and randomly assigned to either a DMBA (n=40) treatment with HFHS (n=20) and DR (n=20) diets; or a control (CNTL) (n=18) treatment with HFHS (n=10) and DR (n=8) diets. At 4 wks of age, two plastic running wheels were mounted inside standard rat cages, and connected to a computer to record WR duration and distance. At 7-9 wks of age, mice were gavaged with DMBA dissolved in corn oil (20 μg/mouse/day) or with corn oil vehicle only (CNTL) for 5 days/wk for 6 weeks. A two-way ANOVA was employed to determine the effect of DMBA on activity with factors of treatment and diet for wks 9-20. RESULTS: Compared to CNTL, DMBA significantly decreased distance (7.41 ± 0.45 vs. 11.08 ± 0.68 km/day; p=0.0002), and duration (175.19 ± 8.24 vs. 261.23 ± 12.36 min; p<0.0001). No significant difference in speed was noted (40.31 ± 1.37 vs. 40.34 ± 2.05 m/min; p=0.77). HFHS diet compared to DR diet significantly decreased distance (5.84 ± 0.60 vs. 11.08 ± 0.55 km/day; p<0.0001), duration (168.41 ± 10.9 vs. 233.14 ± 10.1 min; p<0.0001), and speed (33.04 ± 1.81 vs. 47.12 ± 1.67 m/min; p<0.0001). No significant interactions were observed between treatment and diet groups. CONCLUSIONS: DMBA and HFHS diet decrease WR distance and duration, while only the HFHS diet decreased WR speed. Although DMBA and HFHS independently decreased WR, a lack of interaction suggest that they are not additive or synergistic. ACKNOWLEDGMENTS: Project was funded by the US Army through the Department of Defense projects W81XWH-13-1-0278 (Fuchs-Young) and W81XWH-13-1-0279 (Lightfoot).

Dysregulation of Autophagy Contributes to Anal Carcinogenesis.

IntroductionAutophagy is an intracellular catabolic process that removes and recycles unnecessary/dysfunctional cellular components, contributing to cellular health and survival. Autophagy is a highly regulated cellular process that responds to several intracellular signals, many of which are deregulated by human papillomavirus (HPV) infection through the expression of HPV-encoded oncoproteins. This adaptive inhibitory response helps prevent viral clearance. A strong correlation remains between HPV infection and the development of squamous cell carcinoma (SCC) of the anus, particularly in HIV positive and other immunosuppressed patients. We hypothesize that autophagy is inhibited by HPV–encoded oncoproteins thereby promoting anal carcinogenesis (Fig 1).Materials and MethodsHPV16 transgenic mice (K14E6/E7) and non-transgenic mice (FVB/N), both of which do not spontaneously develop anal tumors, were treated topically with the chemical carcinogen, 7,12-Dimethylbenz[a]anthracene (DMBA), to induce anal cancer. The anuses at different time points of treatment (5, 10, 15 and 20 weeks) were analyzed using immunofluorescence (IF) for two key autophagy marker proteins (LC3β and p62) in addition to histological grading. The anuses from the K14E6/E7 mice were also analyzed for visual evidence of autophagic activity by electron microscopy (EM). To see if there was a correlation to humans, archival anal specimens were assessed histologically for grade of dysplasia and then analyzed for LC3β and p62 protein content. To more directly examine the effect of autophagic inhibition on anal carcinogenesis, nontransgenic mice that do not develop anal cancer with DMBA treatment were treated with a known pharmacologic inhibitor of autophagy, chloroquine, and examined for tumor development and analyzed by IF for autophagic proteins.ResultsHistologically, we observed the progression of normal anoderm to invasive SCC with DMBA treatment in K14E6/E7 mice but not in nontransgenic, syngeneic FVB/N background control mice. With the development of low-grade dysplasia in the K14E6/E7 mice, there was an increase in both punctate LC3β and p62 expression while EM revealed increased autophagosomes without evidence of autophagolysosomes. These observations are consistent with autophagy being inhibited at a later stage in the autophagic process. In contrast, in high-grade dysplasia and SCC in the DMBA-treated K14E6/E7 mice, there were decreased levels of p62 with a continued increase in punctate LC3β expression by IF, while autophagolysosomes were seen on EM, consistent with the process of autophagy proceeded to completion. Similar findings, including histological grade dependent changes in LC3β and p62 expression, were noted with human samples upon analysis of IF. Finally, with pharmacologic inhibition of autophagy in DMBA-treated, nontrangenic FVB/N mice, there was a significant increase in anal cancer development similar to that observed in DMBA- treated K14E6/E7 mice.ConclusionAutophagic dysregulation is noted early on in HPV-associated anal carcinogenesis (low-grade dysplasia), with normalization of the autophagic process arising in late stages of HPV-associated anal carcinogenesis (high-grade dysplasia and invasive carcinoma).

Abstract 5252: Skin cancer prevention by traditional Chinese medicinal formula Si-Wu-Tang and its constituents

Abstract Si-Wu-Tang (SWT), comprising the combination of four herbs, Rehmanniae, Angelica, Chuanxiong and Paeoniae, is one of the most popular Chinese medicines for women's diseases. Previously we showed that SWT was able to upregulate genes in the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway, suggesting a potential application for cancer chemoprevention. The present study examined the chemopreventive activity of SWT using models of skin carcinogenesis. In JB6 P+ cells, a non-cancerous murine epidermal cell line for studying skin tumor promotion, SWT inhibited epidermal growth factor (EGF)-induced neoplastic transformation. In a 7,12-dimethylbenz(a)anthracene (DMBA)-induced murine skin tumorigenesis model, both topical and oral treatment of SWT inhibited epidermal hyperplasia, proliferating cell nuclear antigen expression, and H-ras mutations induced by DMBA treatment. In addition, SWT exhibited a significant antimutagenic activity against DMBA-induced mutagenicity, determined by the Ames Test using Salmonella typhimurium TA100 in the presence of metabolic activator S9 system. To identify active components in SWT, among nine compounds previously reported in commercial SWT products, in silico molecular docking analysis predicted some as potential Nrf2 activators due to an ability of interfering the forming of Nrf2-Keap1 complex. Three of these compounds, gallic acid, Z-liguistilide and senkyunolide A, were confirmed with highest potency of increasing the antioxidant response element luciferase reporter activity, inducing Nrf2-regulated genes Hmox1, Slc7A11 and Nqo1, and inhibiting EGF-induced JB6 P+ transformation. Further mechanistic studies showed that SWT and the three compounds suppressed EGF-induced activation of the activator protein 1 (AP-1), an essential transcription factor involved in skin carcinogenesis. The antimutagenic activity for the three compounds was also confirmed with the Ames Test. In conclusion, these results provide evidence that SWT and its constituents are able to prevent skin cancer, at least partly, by activating the Nrf2 pathway and blocking the activation of AP-1. Thus, this widely used Chinese medicinal formula may provide a promising option toward preventing skin cancer or may be other types of cancer. Citation Format: Kevin Huang, Mandy Liu, Suhui Zhang, Steven Yeung, Andy Chang, Li Qian, Payal Chatterjee, Rui Li, Su Zhou, Nan Mei, Zhijun Wang, Cyrus Parsa, Robert Orlando, Yun Luo, Ying Huang. Skin cancer prevention by traditional Chinese medicinal formula Si-Wu-Tang and its constituents. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5252.

CYP1A1 and GSTm expression of hepatocytes induced by 7,12-dimethylbenz(a)anthracene and the influence of ethanolic extract of Gynura procumbens

The cytochrome P-450 (CYP) and glutathione S-transferase (GST) enzyme systems may influence the biological effects of carcinogens. As such, these enzymes may predict the developmental risk of breast cancer, as well as be potential targets for chemoprevention. The purpose of this study was to compare the expression of CYP1A1 and GST* between treatment groups. Expression of CYP1A1 and GST* was quantified in liver tissue from 18 female Sprague Dawley rats aged 40 days, which randomly divided into six treatment groups. Those are base line group (without DMBA and ethanolic extract treatment), DMBA induced cancer group, the other two groups was administrated by DMBA after treated by ethanolic extract in two different doses, 300 mg /kg BW and 750 mg/kg BW. The last two groups were given two doses of extract ethanolic only, without initiated of DMBA. The ingestion of the extract was carried for three weeks and the ingestion of DMBA was performed twice in the third week. The expression CYP1A1 and GST was quantified by immunohistochemistry. CYP1A1 expression was significantly higher (P < 0.05) in cancer group (DMBA) as compared with other groups. On the other hand, GST expression was lower in cancer group (P < 0.05). Result of this study demonstrated that ethanolic extract leaves of G. procumbens in 300 mg/kg BW dose could inhibit CYP1A1 stronger than are other and induced GST* level. Has effect on ethanolic extract leaves of G. procumbens has ability in played role of as blocking agent in preventing initiation stage of carsinogenesis, therefore it should be taken into account for chemopreventing agent in mammary carsinogenesis. Key words : Gynura procumbens, breast cancer, Chemopreventive, CYP1A1, GSTμ

DMBA specific induces Treg proliferation in draining lymph node

Abstract DMBA, a carcinogenic agent which can induce organism tumor production, was used as a tumor inducer to analyze the draining lymph node T cell development in the skin of mice. The results indicated that antigen-specific T cell proliferation was significantly increased in draining lymph node after DMBA treatment, and CD4+ Foxp3+ Treg measurement results showed that the percentage of Treg increased. Compared with the treatment of acetone, OVA or CpG the proliferation of CD4+ Foxp3+ Treg was carcinogenic agent dependence. More importantly, CD4+ Foxp3+ Helios+ T proliferation assay and CD4+ Foxp3-GFP+ T and CD4+ Foxp3-GFP− T adoptively transfer result indicated the proliferation of Treg was from nTreg but not iTreg. Gene chips assay showed that the expression of energy metabolism relative protein, such as Myo1f and Myl4, and cellular growth regulation protein, such as Anxa2, was significantly up-regulated, which provide a potential target to suppress Treg proliferation during tumor development. This study was supported by the National Natural Science Foundation of China (81272315)

Tumor suppression in mice lacking GABARAP, an Atg8/LC3 family member implicated in autophagy, is associated with alterations in cytokine secretion and cell death.

GABARAP belongs to an evolutionary highly conserved gene family that has a fundamental role in autophagy. There is ample evidence for a crosstalk between autophagy and apoptosis as well as the immune response. However, the molecular details for these interactions are not fully characterized. Here, we report that the ablation of murine GABARAP, a member of the Atg8/LC3 family that is central to autophagosome formation, suppresses the incidence of tumor formation mediated by the carcinogen DMBA and results in an enhancement of the immune response through increased secretion of IL-1β, IL-6, IL-2 and IFN-γ from stimulated macrophages and lymphocytes. In contrast, TGF-β1 was significantly reduced in the serum of these knockout mice. Further, DMBA treatment of these GABARAP knockout mice reduced the cellularity of the spleen and the growth of mammary glands through the induction of apoptosis. Gene expression profiling of mammary glands revealed significantly elevated levels of Xaf1, an apoptotic inducer and tumor-suppressor gene, in knockout mice. Furthermore, DMBA treatment triggered the upregulation of pro-apoptotic (Bid, Apaf1, Bax), cell death (Tnfrsf10b, Ripk1) and cell cycle inhibitor (Cdkn1a, Cdkn2c) genes in the mammary glands. Finally, tumor growth of B16 melanoma cells after subcutaneous inoculation was inhibited in GABARAP-deficient mice. Together, these data provide strong evidence for the involvement of GABARAP in tumorigenesis in vivo by delaying cell death and its associated immune-related response.

Fluorescence Identification of Head and Neck Squamous Cell Carcinoma and High-Risk Oral Dysplasia With BLZ-100, a Chlorotoxin-Indocyanine Green Conjugate.

Surgical cure of head and neck squamous cell carcinoma (HNSCC) remains hampered by inadequately resected tumors and poor recognition of lesions with malignant potential. BLZ-100 is a chlorotoxin-based, tumor-targeting agent that has not yet been studied in HNSCC. To evaluate BLZ-100 uptake in models of HNSCC and oral dysplasia. This was an observational study (including sensitivity and specificity analysis) of BLZ-100 uptake in an orthotopic xenograft mouse model of HNSCC and a carcinogen-induced dysplasia model of hamster cheek pouches. Various HNSCC xenografts were established in the tongues of NOD-scid IL2Rgammanull (NSG) mice. BLZ-100 was intravenously injected and fluorescence uptake was measured. To induce dysplasia, the carcinogen 7,12-dimethylbenz(a)anthracene (DMBA) was applied to the cheek pouch of Golden Syrian hamsters for 9 to16 weeks. BLZ-100 was subcutaneously injected, and fluorescence uptake was measured. The signal-to-background ratio (SBR) of BLZ-100 was measured in tumor xenografts. To calculate the sensitivity and specificity of BLZ-100 uptake, a digital grid was placed over tissue sections and correlative histologic sections to discretely measure fluorescence intensity and presence of tumor; a receiver operating characteristic (ROC) curve was then plotted. In the hamster dysplasia model, cheeks were graded according to dysplasia severity. The SBR of BLZ-100 was compared among dysplasia grades. In HNSCC xenografts, BLZ-100 demonstrated a mean (SD) SBR of 2.51 (0.47). The ROC curve demonstrated an area under the curve (AUC) of 0.89; an SBR of 2.50 corresponded to 92% sensitivity and 74% specificity. When this analysis was focused on the tumor and nontumor interface, the AUC increased to 0.97; an SBR of 2.50 corresponded to 95% sensitivity and 91% specificity. DMBA treatment of hamster cheek pouches generated lesions representing all grades of dysplasia. The SBR of high-grade dysplasia was significantly greater than that of mild-to-moderate dysplasia (2.31 [0.71] vs 1.51 [0.34], P = .006). BLZ-100 is a sensitive and specific marker of HNSCC and can distinguish high-risk from low-risk dysplasia. BLZ-100 has the potential to serve as an intraoperative guide for tumor margin excision and identification of premalignant lesions.

ANTIBREAST CANCER ACTIVITY OF NANOPROPOLIS INDONESIA ON INDUCED MAMMARY GLAND TUMOR BY DMBA IN VIRGIN SPRAGUE-DAWLEY RATS

The objective of this study was to determine the effect of nanopropolis to cure cancer induced on rat mammary tumor using 7,12-dimethylbenz(a)anthracene (DMBA). After the first tumors appearance, twenty eight rats were divided into seven groups. Group 1, 2 and 3 served as recipient of nanopropolis dosages 8, 32 and 56 µg/mL treatments; Group 4 served asrecipient of propolis dosage of 233 µg/mL treatment; Group 5 served asrecipient of doxorubicin treatment; Group 6 served as recipient of DMBA treatment and Group 7 as normal group (control). The effect of nanopropolis dosage of 32 µg/mL and propolis dosage of 233 µg/mL were similar in reducing tumor size, healing the wounds caused by the tumor and eliminating cancer cells. It turns out that there is a relationship between particle size absorbent materials. The study suggested that nanopropolis with small concentration was very effective to treatrat mammary gland tumors and breast cancers.Keywords: breast cancer, nanopropolis, propolis, Sprague-Dawley rat

Pomegranate exerts chemoprevention of experimentally induced mammary tumorigenesis by suppression of cell proliferation and induction of apoptosis

abstractBreast cancer is the second leading cause of cancer-related death in women in the United States and discovery and development of safe chemopreventive drugs is urgently needed. The fruit pomegranate (Punica granatum) is gaining importance because of its various health benefits. This study was initiated to investigate chemopreventive potential of a pomegranate emulsion (PE) against 7,12-dimethylbenz(a)anthracene (DMBA) rat mammary carcinogenesis. The animals were orally administered with PE (0.2–5.0 g/kg), starting 2 wk before and 16 wk following DMBA treatment. PE exhibited a striking reduction of DMBA-induced mammary tumor incidence, total tumor burden, and reversed histopathological changes. PE dose-dependently suppressed cell proliferation and induced apoptosis in mammary tumors. Immunohistochemical studies showed that PE increased intratumor Bax, decreased Bcl2 and manifested a proapoptotic shift in Bax/Bcl2 ratio. In addition, our gene expression study showed PE-mediated upregulation of Bad, caspase-3, caspase-7, caspase-9, poly (ADP ribose) polymerase and cytochrome c in mammary tumors. Thus, PE exerts chemoprevention of mammary carcinogenesis by suppressing cell proliferation and inducing apoptosis mediated through upregulation of Bax and downregulation of Bcl2 in concert with caspase cascades. Pomegranate bioactive phytoconstituents could be developed as a chemopreventive drug to reduce the risk of breast cancer.

Marginal zinc intake reduces the protective effect of lactation on mammary gland carcinogenesis in a DMBA-induced tumor model in mice

Breastfeeding can reduce breast cancer risk; however, unknown factors modify this protective effect. Zinc (Zn) modulates an array of cellular functions including oxidative stress, cell proliferation, motility and apoptosis. Marginal Zn intake is common in women and is associated with breast cancer. We reported that marginal Zn intake in mice leads to mammary gland hypoplasia and hallmarks of pre-neoplastic lesions. In the present study, we tested the hypothesis that marginal Zn intake confounds the protective effect of lactation on breast cancer. Nulliparous mice fed control (ZA, 30 mg Zn/kg) or a marginal Zn diet (ZD, 15 mg Zn/kg), were bred and offspring were weaned naturally. Post-involution, mice were gavaged with corn oil or 7,12-dimethylbenz(a)anthracene (DMBA, 1 mg/wk for 4 weeks) and tumor development was monitored. A ZD diet led to insufficient involution, increased fibrosis and oxidative stress. Following DMBA treatment, mice fed ZD had higher oxidative stress in mammary tissue that correlated with reduced levels of peroxiredoxin-1 and p53 and tended to have shorter tumor latency and greater incidence of non-palpable tumors. In summary, marginal Zn intake creates a toxic mammary gland microenvironment and abrogates the protective effect of lactation on carcinogenesis.

7,12-Dimethylbenz(a)anthracene-induced genotoxicity on bone marrow cells from mice phenotypically selected for low acute inflammatory response.

Exposure to polycyclic aromatic hydrocarbon (PAH) environmental contaminants has been associated with the development of mutations and cancer. 7,12-Dimethylbenz(a)anthracene ( DMBA), a genotoxic agent, reacts with DNA directly, inducing p53-dependent cytotoxicity resulting in cell death by apoptosis or giving rise to cancer. DMBA metabolism largely depends on activation of the aryl hydrocarbon receptor (AhR). Mice phenotypically selected for high (AIRmax) or low (AIRmin) acute inflammatory response present a complete segregation of Ahr alleles endowed with low (Ahr(d)) or high (Ahr(b1)) affinity to PAHs, respectively. To evaluate the role of AhR genetic polymorphism on the bone marrow susceptibility to DMBA, AIRmax and AIRmin mice were treated with a single intraperitoneal injection of DMBA (50mg/kg b.w.) in olive oil. Bone marrow cells (BMCs) were phenotyped by both flow cytometry and cytoslide preparations. Despite a significant decrease in total cell count in BM from AIRmin mice, there was an increase of blast cells and immature neutrophils at 1 and 50 days after DMBA treatment, probably due to a cell-cycle blockade at the G1/S transition leading to immature stage cell production. A panel of proteins related to cell cycle regulation was evaluated in immature BM cells (Lin(-)) by Western Blot, and DNA damage and repair were measured using an alkaline version of the Comet assay. In Lin(-) cells isolated from AIRmin mice, high levels were found in both p53 and p21 protein contents in contrast with the low levels of CDK4 and Ciclin D1. Evaluation of DNA repair in DMBA-treated BMCs, indicated long-lasting genotoxicity and cytotoxicity in BMC from AIRmin mice and a blockade of cell cycle progression. On the other hand, AIRmax mice have a high capacity of DNA damage repair and protection. These mechanisms can be associated with the differential susceptibility to the toxic and carcinogenic effects of DMBA observed in these mice.

Chronic unpredictable stress (CUS) enhances the carcinogenic potential of 7,12-dimethylbenz(a)anthracene (DMBA) and accelerates the onset of tumor development in Swiss albino mice.

Social stressors evolving from individual and population interactions produce stress reactions in many organisms (including humans), influencing homeostasis, altering the activity of the immunological system, and thus leading to various pathological states including cancer and their progression. The present study sought to validate the effectiveness of chronic unpredictable stress (CUS) in cancer promotion and to assess oxidative stress outcomes in terms of various in vivo biochemical parameters, oxidative stress markers, DNA damage, and the development of skin tumors in Swiss albino mice. Animals were randomized into different groups based on their exposure to CUS alone, 7,12-dimethylbenz(a)anthracene (DMBA) alone (topical), and DMBA-12-O-tetradecanoylphorbol-13-acetate (TPA) (topical) and exposure to CUS prior to DMBA or DMBA-TPA treatments and sacrificed after 16 weeks of treatment. Prior exposure to CUS significantly increased the pro-oxidant effect of carcinogen, depicted by compromised levels of antioxidants in the circulation and skin, accompanied by enhanced lipid peroxidation, plasma corticosterone, and marker enzymes as compared to DMBA-alone or DMBA-TPA treatments. DNA damage results corroborated the above biochemical outcomes. Also, the development of skin tumors (in terms of their incidence, tumor yield, and tumor burden) in mice in the presence and absence of stress further strongly supported our above biochemical measurements. CUS may work as a promoter of carcinogenesis by enhancing the pro-oxidant potential of carcinogens. Further studies may be aimed at the development of interventions for disease prevention by identifying the relations between psychological factors and DNA damage.

Neonatal exposure of 17β-estradiol has no effects on mutagenicity of 7,12-dimethylbenz [a] anthracene in reproductive tissues of adult mice.

IntroductionBiological studies in animals and epidemiological findings in humans clearly demonstrate that estrogens including 17β-estradiol (E2) are weak carcinogens via both genetic and epigenetic mechanisms. Carcinogenesis analyses have indicated that female mice exposed to E2 as neonates develop more mammary and ovarian tumors when compared to adult exposures. In the present study, Big Blue transgenic mice were used to investigate the effects of E2 on mutagenicity of 7,12-dimethylbenz [a] anthracene (DMBA), a genotoxic carcinogen, in mammary gland and ovary following neonatal exposure.ResultsDMBA treatment resulted in significant increases in cII mutant frequencies (MFs) in both mammary glands and ovaries, with A:T → T:A transversion as the predominant type of mutation. However, co-exposure to E2 daily for the first 5 days after birth and to DMBA at 6 months of age did not significantly increase cII MFs compared to DMBA treatment alone. Further, there were also no significant differences in mutational spectra between DMBA exposure alone and E2 + DMBA treatment.ConclusionThese results suggest that early life exposures of mice to estrogens like E2 do not enhance mutagenicity by subsequent exposure to a chemical like DMBA in later life.Electronic supplementary materialThe online version of this article (doi:10.1186/s41021-015-0011-y) contains supplementary material, which is available to authorized users.

EKSTRAK HEKSAN BIJI JINTAN HITAM (Nigella sativa L) MENINGKATKAN AKTIVITAS FAGOSITOSIS MAKROFAG TIKUS BETINA GALUR SD (Sprague Dawley) YANG DIINDUKSI DMBA (7,12Dimetilbenz(α)antrasen) SECARA IN VITRO

Previous research has shown that black cumin seed oil is as an immunomodulator, but the mechanism MBJH as an immunomodulator in DMBA-induced macrophage unknown. A study to determine the effects of EHBJH on the activities of SD rat peritoneal macrophage phagocytosis induced DMBA has been conducted. This study was conducted on 10 female Sprague Dawley rats were divided into two groups, namely 5 mice without any treatment group and 5 mice DMBA DMBA treatment groups. Once a week administration of 15 mg DMBA of mice,rats dissected and taken peritonealnya fluid for isolation of macrophages to be cultured for 24 hours. The peritoneal macrophages were given hexane BJH ( Nigella sativa Lour) as much as 1 mg/mL, 5 mg/mL, 25 mg/mL, and were given a standard timokuinon for each group without induction DMBA and DMBA treatment groups. Macrophages were incubated for 2 hours back. Phagocytosis test is done by adding the latex particles on cultured macrophages and Giemsa staining. Data percentage of macrophages that eat latex and phagocytosis index were analyzed using the Kolmogorov-Smirnov test followed by ANOVA and LSD test with a 95% confidence level. The results showed that the activity and phagocytosis index DMBA -induced macrophages that is not greater than the index of activity and macrophage phagocytosis induced macrophages (p<0.05). A group of 25 mg/mL EHBJH have activity and phagocytosis index is highest when compared with the other treatment group (p<0.05). Conclusion: The study showed that the hexane BJH ( Nigella sativa Lour) can improve macrophage phagocytic activity of female rats Sprague Dawley strain.

Effects of Flaxseed Lignan Secoisolariciresinol Diglucosideon Preneoplastic Biomarkers of Cancer Progression in a Model of Simultaneous Breast and Ovarian Cancer Development

Breast cancer prevention efforts are focused increasingly on potentially beneficial dietary modifications due to their ease of implementation and wide acceptance. Secoisolariciresinol diglucoside (SDG) is a lignan found in high concentration in flaxseed that may have selective estrogen receptor modulator-like effects resulting in antiestrogenic activity in a high estrogen environment. In parallel with a human phase II prevention trial, female ACI rats (n = 8–10/group) received 0, 10, or 100 ppm SDG in the feed. The 100 ppm SDG treatment produced similar blood lignan levels as those observed in our human pilot study. Mammary and ovarian cancer progression were induced using local ovarian DMBA treatment and subcutaneous sustained release 17β-estradiol administered starting at 7 weeks of age. Mammary gland and ovarian tissues were collected at 3 mo after initiation of treatment and examined for changes in epithelial cell proliferation (Ki-67, cell counts), histopathology, and dysplasia scores, as well as expression of selected genes involved in proliferation, estrogen signaling, and cell adhesion. Treatment with SDG normalized several biomarkers in mammary gland tissue (dysplasia, cell number, and expression of several genes) that had been altered by carcinogen. There is no indication that SDG promotes preneoplastic progression in the ovarian epithelium.

Lyophilized strawberries prevent 7,12-dimethylbenz[α]anthracene (DMBA)-induced oral squamous cell carcinogenesis in hamsters

This study evaluated the ability of lyophilized strawberries to prevent 7,12-dimethylbenz[α]anthracene (DMBA)-induced tumor development in hamster cheek pouch. The experimental diet containing 5% strawberries was given to hamsters during or after DMBA treatment, or throughout the entire bioassay. Our data indicate that tumor incidence, multiplicity, volume and histologic grade of oral precancerous lesions were reduced in animals fed the experimental diet compared to those fed the control diet. We chemically identified and quantified the main phytochemicals by high performance liquid chromatography/tandem mass spectrometry. Fourteen quantified compounds were classified to three categories: anthocyanins (48.8%, w/w of the phenolics), ellagitannin/ellagic acid/ellagic acid derivates (42.9%) and flavonols (8.3%). We further elucidated the molecular mechanisms underlying preventive activities of strawberries. Our mechanistic studies show that strawberries suppress cell proliferation, angiogenesis and oncogenic signaling. Moreover, feeding 5% strawberries also significantly decreased arachidonic acid metabolism and formation of 8-hydroxydeoxyguanosine. These observations suggest that strawberries inhibit DMBA-induced oral cancer in hamsters through suppression of multiple oncogenic events, and thus may serve as alterative agents for oral cancer prevention in humans.

Effect of zinc and polyphenols supplementation on antioxidative defense mechanisms and the frequency of microsatellite instability in chemically-induced mammary carcinogenesis in the rat

The aim of the present study was to assess the effect of dietary supplementation (with zinc or zinc and polyphenolic compounds - resveratrol or genistein) on antioxidant enzymes (glutathione peroxidase - GPx, catalase - CAT and superoxide dismutase - SOD) and the frequency of microsatellite instability (MSI) in a widely used model of mammary carcinogenesis induced in the rat by treatment with 7,12-dimethyl-1,2-benz[a]anthracene (DMBA). The impact of selected compounds on the intensity of DMBA-induced carcinogenesis was also assessed. Sixty four Sprague-Dawley female rats were divided into study groups which, apart from the standard diet and DMBA, were treated with zinc, zinc and resveratrol or zinc and genistein via gavage for a period ranging from 40 days to 20 weeks of age. On the basis of the obtained results it can be said that synergistic reaction between Zn(II) and genistein causes a delay in cancer development as compared with the animals treated with DMBA but with no food supplementation. Supplementation with Zn(II) and polyphenolic compounds resulted in the occurrence of microsatellite instabilities in tumors. LOH (loss of heterozygosity) was found in tumor samples at microsatellite D1Mgh6 and D3Mgh9. DMBA treatment increased significantly the glutathione peroxidase activity whereas it had no effect on the SOD and CAT activities, as compared with control rats. Diet supplementation has an effect on the activity of selected antioxidant enzymes. Diet supplementation has an effect on the occurrence of microsatellite instabilities as well as on the intensity of the neoplastic process. The intensity of occurrence of microsatellite instabilities does not depend on the activity of selected antioxidant enzymes.

Combinatorial chemopreventive effect of butyric acid, nicotinamide and calcium glucarate against the 7,12-dimethylbenz(a)anthracene induced mouse skin tumorigenesis attained by enhancing the induction of intrinsic apoptotic events

We explored the basis of the combinatorial chemopreventive effect of butyric acid (BA), nicotinamide (NA) and calcium glucarate (CAG) on mouse skin exposed to 7,12-dimethylbenz(a)anthracene (DMBA). We studied the effects of topical application of DMBA in the presence or absence of BA, NA and CAG on the regulators of apoptosis. DMBA treatment suppressed Bax, Bax/Bcl-2 ratio, release of cyt c, Apaf1, caspase-9, -3 mediated apoptosis. Downregulation of p21 and upregulation of Bcl-2, mut p53 were also observed in only DMBA treated mice. Simultaneous application of BA, NA and CAG induced a mitochondria-mediated apoptosis, characterized by a rise in the Bax, Bax/Bcl-2 ratio, release of cyt c, upregulation of Apaf1 with down-stream activation of caspase-9, -3. Furthermore treatment with BA, NA and CAG demonstrated an upregulation of p21 and downregulation of Bcl-2, mut p53. But this effect was enhanced in the presence of all the three compounds together in combination. Chemoprevention by a combination of BA, NA and CAG by inducing the apoptosis, the natural cell death, suggest the importance of the potential combinational strategies capable of preventing skin tumor development.