Single Dose Of DMBA Research Articles

Phytochemical characterization and assessment of antitumor activity of the aqueous extract of Acmella caulirhiza in female Wistar rats induced by 7,12 dimethylbenz (a) anthracene

BackgroundRecent studies increasingly show the implication of medicinal plants in cancer management. Acmella caulirhiza, a plant belonging to the Asteraceae is traditionally used as an analgesic and anti-inflammatory agent to fight against diseases like cancer. Purpose: This study aimed to evaluate the antitumoral properties of the aqueous extract of leaves and flowers of A. caulirhiza (AE-Ac). MethodsAfter phytochemical characterization, the cytotoxic activity of AE-Ac on MCF-7 breast cancer lines was carried out using the MTT method. For in vivo study, 36 female Wistar rats (6 weeks old) were randomly divided into 6 groups (n = 6 each) as follows: normal control receiving distilled water (NC), positive control receiving distilled water (DMBA), 3 test groups (receiving either 75, 150 or 300 mg/kg.Bw of AE-Ac (AE-Ac 75, AE-Ac 150 and AE-Ac 300 respectively)) and a reference group (Tam) receiving Tamoxifen at 3.3 mg/kg.Bw. They were fed with a high-fat diet daily. After 2 weeks all groups except the NC group were treated with a single dose of DMBA (7,12-Dimethylbenz (a) anthracene) (50 mg/kg. Bw) by intraperitoneal injection. Daily treatments were administered by intragastric intubation for 12 weeks. At the end, animals were sacrificed after 12 h of fasting and blood was collected for biochemical analysis. The mammary glands were isolated for histological analysis. ResultsAE-Ac contains bioactive compounds amongst which stigmasterol, phytol, ellagic acid, phenol, sterols, alkaloids, flavonoids. AE-Ac was more active at 72 h (IC50 = 114.86 µg/mL) on MCF-7 cells. The cancer-treated groups exhibited the lowest percentage of weight gain variation, particularly the group receiving the reference molecule (Tamoxifen) (68.12 %) followed by the AE-Ac 150 group (92.45 %). AE-Ac at 150 and 300 mg/kg-Bw significantly reduced tumor volume and CA 15-3 levels (p = 0.004). Histological analysis of the mammary gland revealed more extensive ascini destruction in the AE-Ac 75 group followed by the DMBA group. Treatment with the 150 mg/kg.Bw ameliorated antioxidant enzyme (SOD and Catalase (p < 0.001)) activities, pro-oxidant levels (NO● and HO●), as well as inflammatory parameters (TNF-α and EGF; RBC, Hb, PLT) (p < 0.05). ConclusionThese results suggest that AE-Ac can be a good candidate as a complementary agent in breast cancer management.

Annona Muricata L. extract restores renal function, oxidative stress, immunohistochemical structure, and gene expression of TNF-α, IL-β1, and CYP2E1 in the kidney of DMBA-intoxicated rats.

Introduction: 7,12-dimethylbenz (a) anthracene (DMBA) is a harmful polycyclic aromatic hydrocarbon derivative known for its cytotoxic, carcinogenic, and mutagenic effects in mammals and other species. Annona muricata, L. (Graviola; GRV) is a tropical fruit tree traditionally well-documented for its various medicinal benefits. This investigation is the first report on the potential antioxidant and antinfammatory reno-protective impact of GRV against DMBA-induced nephrotoxicity in rats. Methods: Forty male albino rats were allocated into four equal groups (n = 10). The 1st group served as the control, the 2nd group (GRV) was gastro-gavaged with GRV (200mg/kg b.wt), the 3rd group (DMBA) was treated with a single dose of DMBA (15mg/kg body weight), and the 4th group (DMBA + GRV) was gastro-gavaged with a single dose of DMBA, followed by GRV (200mg/kg b.wt). The GRV administration was continued for 8weeks. Results and Discussion: Results revealed a significant improvement in renal function, represented by a decrease in urea, creatinine, and uric acid (UA) in the DMBA + GRV group. The antioxidant potential of GRV was confirmed in the DMBA + GRV group by a significant decline in malondialdehyde (MDA) and a significant increase in catalase (CAT), superoxide dismutase (SOD), glutathione S transferase (GST), and reduced glutathione (GSH) compared to DMBA-intoxicated rats; however, it was not identical to the control. Additionally, the antiinflammatory role of GRV was suggested by a significant decline in mRNA expression of cytochrome P450, family 2, subfamily e, polypeptide 1 (CYP2E1), tumor necrosis factor-alpha (TNF-α), and interleukin 1 beta (IL-1β) in the DMBA + GRV group. Moreover, GRV improved the histopathologic and immunohistochemical expression of TNF-α, CYP450, and IL1β in DMBA-intoxicated kidney tissue. Conclusively, GRV is a natural medicinal product that can alleviate the renal injury resulting from environmental exposure to DMBA. The reno-protective effects of GRV may involve its anti-inflammatory and/or antioxidant properties, which are based on the presence of phytochemical compounds such as acetogenins, alkaloids, and flavonoids.

Acidic Exo-Polysaccharide Obtained from Bacillus sp. NRC5 Attenuates Testosterone-DMBA-Induced Prostate Cancer in Rats via Inhibition of 5 α-Reductase and Na+/K+ ATPase Activity Mechanisms

Bacillus sp. NRC5 is a new strain that grows in Egyptian beaches. This strain produces acidic exo-polysaccharide that have excellent antioxidant, anti-inflammatory and anti-tumor properties. The current study aimed to introduce a new natural product feasible for prostate cancer therapies. The anti-prostate cancer of acidic exo-polysaccharide produced from marine Bacillus sp. NRC5 (EBPS) was determined using 7,12-dimethylbenz-(a)-anthracene; DMBA-induced prostate cancer in male Sprague Dawley rats. Rats were subcutaneously injected with testosterone (3 mg/kg/day for 3 months) and a single dose of DMBA (65 mg/kg) for induction of prostate cancer. EBPS was administrated orally at dose 200 mg/kg/day for 3 months. To study protective effect of EBPS, animals received EBPS before cancer induction, meanwhile in therapeutic effect animals received EBPS after cancer induction. EBPS debug oxidative stress and inflammatory conditions associated with prostate cancer. EBPS either protective or therapeutic material considerably reduced cancer growth rate-limiting enzyme—i.e., 5-α-reductase (46.89 ± 1.72 and 44.86 ± 2.56 µg Eq/mL) and Na+/K+ ATPase (0.44 ± 0.03 and 0.42 ± 0.02 µg Eq/mL), compared to cancer control (69.68 ± 3.46 µg Eq/mL). In addition, both cancer biomarkers—i.e., prostate-specific antigen and carcinoembryonic antigen were significantly lowered as evidence of the ability of EBPS to protect and treat prostate cancer in chemically induced rats. EBPS showed protective and therapeutic efficacy on testosterone–DMBA-induced prostate cancer rats with a good safety margin. This study may go to clinical trials after a repeated study on another type of small experimental animal, their offspring, and one big experimental animal.

Chemomodulatory Effect of Capsaicin Encapsulated Chitosan Nanoparticles on Lipids, Lipoproteins and Glycoprotein Components in DMBA Induced Mammary Carcinogenesis in Rats

Objectives: Breast cancer is a dreadful public health issue that kills plenty of women all around the world. The peril of breast cancer is strongly linked to lipids, lipoproteins, and glycoproteins. Capsaicin (CAP), a natural alkaloid isolated from chilies, has been reported to possess excellent anti-cancer activity. Unfortunately, the clinical application of this compound is strictly limited due to its low solubility and poor bioavailability. Nanoparticle-based drug delivery systems have set the path for a revolution in cancer therapy by improving its therapeutic value. The aim of the present study was to investigate the effect of CAP encapsulated chitosan nanoparticles (CAP@CS-NP) on lipids, lipoproteins and glycoproteins abnormalities in 7,12-dimethylbenz(a)anthracene (DMBA) induced mammary carcinogenesis. Methods: A mammary tumor was induced by a single dose of DMBA 25mg/kg b.wt injected subcutaneously near the mammary gland. The levels of lipid profile, lipoproteins and glycoprotein components were analyzed in the plasma, liver and mammary tissues. Results: We observed higher levels of total cholesterol (TC), triglycerides (TG), phospholipids (PL), free fatty acids (FFA), hexose, hexosamine and sialic acid in DMBA induced tumor-bearing rats. Moreover, low-density lipoprotein cholesterol (LDL-C) and very low-density lipoprotein cholesterol (VLDL-C) levels were raised and high-density lipoprotein cholesterol (HDL-C) levels were dropped in tumor-bearing rats. The result shows that, CAP@CS-NP 4mg/kg b.wt administration significantly recouped abnormal levels to near-normal levels. It was additionally verified by histological staining in mammary tissues. Conclusion: Our findings suggest that nanoencapsulation of CAP@CS-NP successfully regulates lipid profile, lipoproteins, and glycoproteins levels. Keywords: Breast cancer, Capsaicin, Nanoparticle, Glycoproteins, Lipids

Different properties of mammary carcinogenesis induced by two chemical carcinogens, DMBA and PhIP, in heterozygous BALB/c Trp53 knockout mice

Chemical carcinogens, such as 7,12-dimethylbenz[a]anthracene (DMBA) and 2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine (PhIP), are known to induce mammary carcinomas in mice and rats. In the present study, the phenotypic and genotypic characteristics of carcinogen-induced mammary carcinogenesis in heterozygous BALB/c tumor protein p53 (Trp53) knockout mice were examined with reference to published data surrounding human breast cancer. A significantly accelerated induction of mammary carcinomas was observed following a single dose of DMBA (50 mg/kg of body weight at 7 weeks of age), and a modest acceleration was induced by PhIP (50 mg/kg of body weight) administered by gavage 6 times/2 weeks from 7 weeks of age. DMBA-induced mammary carcinomas were histopathologically characterized by distinct biphasic structures with luminal and myoepithelial cells, as well as a frequent estrogen receptor expression, and PhIP-induced carcinomas with solid/microacinar structures consisted of pleomorphic cells. Of note, DMBA-induced mammary carcinomas were characterized by a HRas proto-oncogene (Hras) mutation at codon 61, and gene/protein expression indicating MAPK stimulation. PhIP-induced lesions were suspected to be caused by different molecular mechanisms, including Wnt/β-catenin signaling and/or gene mutation-independent PI3K/AKT signaling activation. In conclusion, the present mouse mammary carcinogenesis models, induced by a combination of genetic and exogenous factors, may be utilized (such as the DMBA-induced model with Trp53 gene function deficiency as a model of adenomyoepithelioma, characterized by distinct biphasic cell constituents and Hras mutations), but PhIP-induced models are required to further analyze the genetic/epigenetic mechanisms promoting mammary carcinomas.

Dose-dependent chemopreventive effects of citronellol in DMBA-induced breast cancer among rats.

Breast cancer is one of the most common cancers among women world wide and its incidence is on tremendous increase. The present study is aimed to analyze the dose-dependent chemopreventive efficacy of citronellol on 7,12-dimethylbenz(a)anthracene (DMBA)-induced rat mammary carcinogenesis. The mammary tumor was induced through a single dose of DMBA (25 mg/rat) injected subcutaneously near the mammary gland of rats. In DMBA-injected rats, 100% tumor incidence, increased tumor volume, and tumor burden along with loss of body weight were observed. Biochemical analysis revealed the increased levels of phase I detoxification proteins (cytochrome P450 and b5) and decreased activities of phase II detoxification enzymes (glutathione-S-transferase and glutathione reductase) in hepatic and mammary tissues. The levels of enzymatic and non-enzymatic antioxidants (superoxidedismutase, catalase, glutathione peroxidase, and (GPx) and reduced glutathione) were decreased and lipid peroxidation by-products (thiobarbituric acid reactive substance and lipid hydroperoxide) got increased in plasma and mammary tissues. Oral administration of different doses of citronellol (25, 50, and 100 mg/kg body weight) to DMBA-treated rats for 16 weeks absolutely inhibited the tumor incidence and restored the biochemical parameters near to normal level in 50 and 100 mg doses whereas the histopathological studies also supported the biochemical findings. Hence, the result suggests that the citronellol of 50 mg/kg body weight exerted significant chemopreventive effects and can be considered as a minimum optimum dose in the prevention of mammary carcinogenesis.

Anti-Estrogenic and Anti-Cell Proliferative Effect of Allyl Isothiocyanate in Chemoprevention of Chemically Induced Mammary Carcinogenesis in Rats.

The anti-estrogenic and anti-cell proliferative effect of allyl isothiocyanate (AITC) was carried out by analyzing the status of sex hormones and its receptors and cell proliferative markers in chemically induced mammary carcinogenesis in rats. Mammary tumor was induced by a single dose of DMBA (25mg/rat) and MNU (50mg/kg bw) injected subcutaneously near mammary gland. RT-PCR, western blotting and immunohistochemical analysis of mammary tissues show an upregulation of ER-α, PR, aromatase, PCNA, cyclin D1 and AgNORs staining and down regulation of p53 expression as well as plasma estradiol, prolactin and testosterone levels increased in DMBA and MNU-induced tumor bearing rats. Oral administration of AITC at a dose of 20mg/kg bw restored the levels of sex hormones and its receptors, aromatase, cell proliferative markers and AgNORs staining near to normal levels. Molecular docking studies also supported these findings. The results suggest that anti-estrogenic and anti-proliferative effect of AITC prevent the development of DMBA and MNU-induced mammary carcinogenesis in rat.

Biochemical studies evaluating the chemopreventive potential of brucine in chemically induced mammary carcinogenesis of rats

The present study was aimed to investigate the dose dependent chemopreventive activity of brucine against 7, 12-dimethylbenz (a) anthracene induced mammary gland tumorigenesis in rats. The mammary tumor was induced by a single dose of DMBA (25 mg/rat) injected subcutaneously near the mammary gland. We observed reduced body weight and increase in tumor incidence, the total number of tumors, and tumor volume in DMBA alone injected rats and also observed decreased antioxidant status (SOD, CAT, GPX, and GSH) and increased lipid peroxidation (TBARS and LOOH) in plasma and mammary tissues. Increased levels of CYP450, Cyt-b5 and decreased levels of phase II (GST and GR) biotransformation enzymes were noticed in the liver and mammary tissues. Further, increased levels of lipid profile (TC, TG, PL, and FFA) and lipoprotein (LDL and VLDL) were noticed. Whereas, decrease in the levels of HDL in plasma and decreased levels of PL and FFA in mammary tissues were observed. Oral administration of brucine in different doses (2, 4 and 8 mg/kg bw) inhibited the tumor incidence and restored the levels of biochemical markers near to normal in dose responsive manner. Biochemical findings are supported by histopathological studies. The results suggest that brucine at a dose of 8 mg/kg bw shows more significant chemopreventive activity in DMBA-induced mammary carcinogenesis.

Inhibitory Effect of Honey on 7,12-Dimethylbenz(a)anthracene- Initiated and Croton Oil-Promoted Skin Carcinogenesis

Background: Honey as a natural product exhibits a variety of biological and pharmacological activities. Its anti-inflammatory, antioxidant, antibacterial, and antihypertensive effects have already been proven. Objectives: In this study, the inhibitory effects of honey on the 7,12-dimethylbenz(a)anthracene-initiated and croton oil-promoted mice skin carcinogenesis were studied. Methods: Albino Swiss mice were pretreated with multiple topical applications of honey. After nine hours, the carcinogenesis was initiated by a single dose of DMBA. Topical croton oil, as for a promoting agent, was applied biweekly for a period of 30 weeks. Results: The tumor incidences were observed. Compared to the control group, the honey pre-treated mice showed a significant inhibition in tumor incidences. In addition, the enhanced uptake of [3H]-thymidine in mice skin DNA was inhibited in honey-pretreated animals as compared to the control group. Conclusions: Taken together, the results suggest that the antioxidants existed in honey have diminishing effects on croton oilmediated murine skin tumor promotion. In conclusion, we suggest that honey as an effective natural preventive agent may provide protection against skin cancer

Allyl isothiocyanate, a potent chemopreventive agent targets AhR/Nrf2 signaling pathway in chemically induced mammary carcinogenesis.

In the present study, we investigated the effect of allyl isothiocyanate (AITC) on liver detoxification signaling pathway in 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary carcinogenesis. Mammary tumor was induced by a single dose of DMBA (25mg/rat) injected subcutaneously near the mammary gland in Sprague-Dawley rats. DMBA-alone-treated rats show an increased synthesis of phase I detoxification enzymes, lipid peroxidative markers, liver marker enzymes, and lipid profiles whereas, depletion of phase II detoxification enzymes and antioxidants in rat liver tissues. Oral administration of AITC restored the levels of biochemical markers in DMBA-treated rats.Furthermore, histopathological results also confirmed that AITC protects DMBA-mediated hepatocellular damage. We also observed that AITC treatment significantly downregulates AhR and upregulates the expression of Nrf2 in DMBA-treated rats. The binding efficacy of AITC with AhR and Nrf2 analysis by molecular docking studies reveals that AITC has strong interaction with AhR and Nrf2 proteins through hydrogen and hydrophobic interactions. Thus, AITC prevents DMBA-induced mammary carcinogenesis via inhibition of phase I and induction of phase II detoxification enzymes by modulating AhR/Nrf2 signaling pathway.

Protective Effect of Allyl Isothiocyanate on Glycoprotein Components in 7,12-dimethylbenz(a)anthracene Induced Mammary Carcinoma in Rats

The present study aimed to investigate the protective effect of allyl isothiocyanate (AITC) on glycoprotein components in 7,12-dimethylbenz(a)anthracene (DMBA) induced mammary carcinogenesis in female Sprague-Dawley rats. Mammary tumor was induced by a single dose of DMBA (25mg/rat) injected subcutaneously near mammary gland. The levels of glycoprotein components such as hexose, hexosamine and sialic acid were analyzed colorimetrically in plasma, mammary and liver tissues. We observed an increased levels of glycoprotein components in plasma, mammary and liver tissues in cancer bearing rats. It was further confirmed by Periodic Acid Schiff staining in mammary and liver tissues. Upon oral administration of AITC to DMBA injected rats, the abnormal changes were reverted back to near normal levels and biochemical findings are supported by histological analysis. This could be due to the anti-neoplastic potential of AITC against DMBA-induced mammary carcinogenesis. The result shows that AITC has the potential to inhibit abnormal glycosylation that favors neoplastic transformation.

Abstract 4576: Early-in-life dietary zinc supplementation or deficiency and susceptibility to mammary carcinogenesis in female Sprague-Dawley rat

Abstract Zinc deficiency during pregnancy and early postnatal life can adversely affect the health and predispose to an increased risk of developing chronic diseases at adulthood. The present study was designed to evaluate whether exposure to the dietary zinc supplementation or deficiency during the pregnancy, lactation and juvenile stages interferes with the development of mammary gland and susceptibility to the mammary carcinogenesis induced by 7,12-dimethylbenzanthracene (DMBA) in female Sprague-Dawley (SD) rats. Pregnant females were allocated into three groups (n = 15 each): dams received diets containing normal levels (35mg/Kg), deficient (3mg/Kg) or with supplementation (180mg/Kg) of zinc during gestational day 10 (GD 10) until the weaning of litters. After weaning, the females offspring were allocated into three groups and received the same diets as their dams until postnatal day PND 51 or 53. On PND 51, females SD (n = 10, 1 pulp/litter) were euthanized for removal of the abdominal mammary tissue for whole mount analysis or received a single dose of DMBA (50mg/kg, ig) for initiation of mammary carcinogenesis and euthanized on PND 53 (n = 10, 1 pulp/litter) or PND 180 (n = 16, 1 pulp/litter). On PND 53, mammary glands were collected for cell proliferation, apoptosis and estrogen receptor alpha (ER-α) immunohistochemistry analyzes, as well as evaluation the expression of genes related to DNA damage and repair, apoptosis, cell cycle and signaling related to estrogen receptor and p53 by TaqMan Low-density Array (TLDA).Tumors collected at PND 180 were processed for histological evaluation. Male and female offspring from dams receiving dietary zinc deficiency presented a significant reduction in body weight on PND 0, 10, 21 e 51. The mean number of the terminal buds (TEBs), ducts terminal (TEDs) and alveolar buds (ABs) in mammary gland did not differ among the groups. Dietary zinc supplementation significantly increased the indexes of cell proliferation in the mammary glands in relation to the control group while the indexes of apoptosis and ER-α did not differ among the groups. Also, dietary zinc supplementation significantly led downstream of Api5 and Ercc1 target genes related to apoptosis inhibitor and DNA repair, respectively. Also, dietary zinc supplementation or deficiency did not significantly change the histological pattern, volume, latency, incidence or multiplicity of mammary tumors in relation to the control group. However, dietary zinc supplementation increased the tumors number in 72%. The present findings suggest that the treatment with zinc suplementation during the stages of pregnancy, lactation and juvenile could have increased the susceptibility to development of mammary tumors induced by DMBA. Citation Format: Flávia Regina Moraes Silva, Lucas Tadeu Bidinotto, Robson Francisco Carvalho, Luis Fernando Barbisan. Early-in-life dietary zinc supplementation or deficiency and susceptibility to mammary carcinogenesis in female Sprague-Dawley rat. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4576. doi:10.1158/1538-7445.AM2015-4576

Dose response chemopreventive potential of allyl isothiocyanate against 7,12-dimethylbenz(a)anthracene induced mammary carcinogenesis in female Sprague-Dawley rats

The present study aimed to investigate the dose response chemopreventive potential of allyl isothiocyanate (AITC) against 7,12-dimethylbenz(a)anthracene (DMBA) induced mammary carcinogenesis in female Sprague-Dawley rats. Mammary tumor was induced by a single dose of DMBA (25mg/rat) injected subcutaneously near mammary gland. We observed reduced body weight and increased in total number of tumors, tumor incidence and tumor volume in DMBA-induced rats. We also observed decreased antioxidant status (SOD, CAT, GPX and GSH) and increased lipid peroxidation (TBARS and LOOH) in plasma and mammary tissues. Increased levels of CYP450, Cyt-b5 and decreased levels of phase II (GST and GR) biotransformation enzymes noticed in liver and mammary tissues of DMBA-induced rats. Further, increased levels of lipid profile (TC, TG, PL and FFA) and lipoprotein (LDL and VLDL) were noticed. Whereas, decreased level of HDL in plasma and decreased levels of PL and FFA in mammary tissue. Oral administration of AITC different doses (10, 20 and 40mg/kgbw) inhibited the tumor incidence and restored levels of biochemical markers. Biochemical findings are supported by histopathological studies. These results suggested that AITC at a dose of 20mg/kgbw significantly exert chemopreventive potential against DMBA-induced mammary carcinogenesis.

울금 투여에 의한 DMBA 유발 랫드 유선암화과정 억제효과

The purpose of this study was to examine the potential of turmeric (Curcuma longa L.) to inhibit 7,12-dimethylbenz[a]anthracene (DMBA)-induced mammary carcinogenesis in rats. Female Sprague Dawley rats were fed a control diet (NC and DC) or an ethanol extract of turmeric (DT) diet until the end of the experiment. The rats in the DC and DT groups were administered a single dose of DMBA (50 mg/Kg) by oral gavages at 50 days of age. The turmeric ethanol extracts decreased the incidence and multiplicity of DMBA-induced mammary tumor. The turmeric ethanol extract significantly decreased the tumor cell proliferation. The turmeric also significantly decreased the tumor grade based on the degree of the tubule formation. The results suggest that the ethanol extract of turmeric has an inhibitory effect against mammary carcinogenesis, and that such chemopreventive effect may be related to the inhibition of the initiation and the proliferation of tumor cells.

Methylthio Acetic Acid in Japanese Pickling Melon as a Potential Chemopreventive Agent against in Vitro and in Vivo Carcinogenesis System

The cancer preventive activity of vegetables have received a great deal of attention from cancer researchers and study fields. During our investigation of the active preventive properties from an excellent source of vegetables and fruits, useful bioassay-guided led to the screening of traditional natural materials. Katsura-uri, an heirloom vegetable in Kyoto (Japanese pickling melon; Cucumis melo var.conomon), is an unsweet fruit, possesses an intense muskmelon-like fragrant and serve traditional vegetable tools for healthy purpose. The application of a new screening procedure which utilizes the synergistic effect of short-chain fatty acids and tumor-promoting diterpene esters, TPA enabled rapid and easy detection of naturally occurring substances (anti-tumor promoters) with inhibition of Epstein-Barrvirus (EBV) activation, using human lymphoblastoid cells. In the course of these studies, female ICR mouse (6 weeks of age) were treated topically with single dose of DMBA as initiator, followed by TPA twice a weekly for 20 weeks as promoter. Tumor incidence were 100% with 6 to 7 per mouse at end of experiment as positive control group. In our observation, Katsura-uri and its components, (methylthio) acetic acid (MTA) treated group cause about 60 – 70% reduction in the average number of tumors per mouse after 20 weeks of experiment, respectively. Taken together, our preliminary data suggest that the ability of Katsura-uri to suppress promoting stages is valuable for tumor growth inhibition

Determination of 7,12-Dimethylbenz[a]Anthracene in Orally Treated Rats by High-Performance Liquid Chromatography and Transfer Stripping Voltammetry

A number of polycyclic aromatic hydrocarbons (PAHs) have been shown to be toxicants, and induce carcinogenic and immunotoxic effects. As a model PAH agent, 7,12-dimethylbenz[a]anthracene (DMBA) was the strongest one tested in terms of its biological activities and biotransformation. A new and simple high-performance liquid chromatographic (HPLC) method with diode-array detection at 290 nm was developed and validated for monitoring of DMBA in different matrices (serum, liver and kidney) of rats orally treated with DMBA. Furthermore, the applicability of adsorptive transfer stripping voltammetry (AdTSV) on the pencil-lead graphite electrode to these samples was illustrated using our previously reported data for bulk aqueous solutions of DMBA. HPLC and AdTSV methods, which were compatible with each other, allowed DMBA to be detected down to the levels of 3.82x10-9 M (0.98 ppb) and 6.73x10-9 M (1.73 ppb), respectively. Olive oil solutions of DMBA in dose 50 mg/kg were orally administered. 60 days after a single dose of DMBA, its concentrations in these biological samples from rats were measured by means of both methods. Because of rapid biotransformation, DMBA could not be detected in serum. Only low levels of the compounds were deposited unchanged in kidney whereas its levels were considerably higher in liver. These methods were also applied to the assay whether there is an influence of the intake of aqueous extracts of Hypericum Perforatum L. plant on the parent DMBA levels accumulated in rat tissues.

Anticancer mechanism of equol in 7,12-dimethylbenz(a)anthracene-treated animals

This study investigated the anticancer effects of equol, the major metabolite of the antioxidant phytochemical daidzein, on 7,12-dimethylbenz(a)anthracene (DMBA)-treated animals and explored its anticancer mechanism. The experiment consisted of two parts. In the first part, Sprague-Dawley rats were given equol daily at 5 and 25mg/kg body weight (BW) for 8 weeks after a single dose of DMBA (100mg/kg BW). As a control, rats were divided into vehicle alone and DMBA alone groups. Equol administration at a higher dose effectively suppressed tumor formation and PCNA over-expression. The activation of p53 by equol subsequently affected the cyclin-dependent kinase inhibitor p21Cip1. This was associated with equol-induced apoptosis in mammary gland tumors, as evidenced by the decreased Bcl-2 expression and increased Bax expression, together with the activation of caspase-3 and poly(ADP-ribose) polymerase (PARP). In the second part, oral pre-administration of equol to mice which received DMBA intragastrically twice a week for 2 weeks significantly decreased their levels of biomarkers (thiobarbituric acid-reactive substances, carbonyl content and serum 8-hydroxy-2-deoxyguanosine) of DMBA-induced oxidative stress. Although several antioxidant enzymes were down-regulated in mice treated with DMBA alone, pre-administration of equol blocked much of this effect, increasing catalase and superoxide dismutase activity in a dose-dependent manner. Although equol did not affect the ratio of oxidized to reduced glutathione, it activated the glutathione peroxidase and glutathione reductase enzymes, and this effect was significant at a dose of 25 mg equol/kg body weight. DMBA treatment induced apoptosis, as shown by a decrease in the Bcl-2 levels and an increase in the levels of Bax, cleaved caspase-3 and poly(ADP-ribose) polymerase. These apoptotic effects were also reversed by equol at all doses tested. Based on these results, equol possesses anticancer activity that suppresses tumor formation via apoptosis induction in rats with DMBA-induced mammary gland tumors. In addition, equol showed a hepatic protective effect by acting as an antioxidant and by reducing apoptosis.

Anti-/pro-apoptotic effects of hesperetin against 7,12-dimetylbenz(a)anthracene-induced alteration in animals

This study investigated the anticancer effects of hesperetin on 7,12-dimethylbenz(a)anthracene (DMBA)-treated animals and explored its anticancer mechanism. The experiment consisted of two parts. First, Sprague-Dawley rats were given hesperetin daily at a dose of 50 mg/kg for 8 weeks after a single dose of DMBA (100 mg/kg). As controls, rats were divided into vehicle alone and DMBA alone groups. Secondly, ICR mice were given hesperetin daily at a dose of 10 and 50 mg/kg BW/day for 7 weeks before a single dose of DMBA (34 mg/kg/week). In rats with DMBA-induced mammary gland tumors, hesperetin pretreatment significantly reduced the tumor burden and PCNA overexpression. The administration of hesperetin significantly inhibited mammary gland carcinoma from developing by restoring the decreased Bcl-2 and increased Bax expression. By contrast, in the livers of mice treated with DMBA, obvious DNA fragmentation was observed. Moreover, apoptosis-related gene expression in the livers of the mice differed from that in mammary gland carcinomas in rats. These changes were restored in mice treated with hesperetin, indicating the inhibition of apoptosis. Based on these results, hesperetin may act not only as a proapoptotic agent, but also as an antiapoptotic agent, depending on the circumstance.

Morphologic evaluation of breast neoplasia in experimental focal hyperthermia

Focal thermotherapy (FT) is a new modality for cancer treatment under study.The objective of this study was to evaluate the morphological changes of breast tumors induced by 7,12‐dimethylbenz[a]anthrace (DMBA).At 53 days of age 24 virgin SD female rats were orally given a single dose of DMBA (65 mg/Kg). Twenty‐six weeks later, animals were randomly allocated to two groups: control group (n=12) and treated group (n=12). The treated group was submitted to FT applied on the largest tumor 60 seconds for two days. The animals were ethically euthanized one week after treatment.Tumors were grouped on: I‐tumors of non‐treated animals; II‐non‐treated tumors of treated animals and III‐tumors injected with ferromagnetic cement heated with electromagnetic energy.The malignant breast tumors were evaluated by histopathology. Apoptosis, necrosis and hemorrhage did not differ significantly between groups I and II, although the frequency of these parameters was higher on group II. On group III there is a significant increase of necrosis compared to group I, and a higher frequency of necrosis and hemorrhage to group II.This preliminary study suggests that FT of one breast carcinoma leads to an increase of necrosis in all tumors of one rat experimental model. Although further studies are needed, FT has great potential for future clinical applications in breast cancer therapy.Grant: FCT‐ PTDC/SAU‐BEB/69497/2006

Evaluation of complementary treatment in DMBA breast cancer model – preliminary results

Over the last decade, conventional breast cancer therapies have been frequently adjuvated with complementary medicine techniques (CMT). In spite of medical evidence, experimental models are required to validate CMT effect on breast cancer.This study has two groups of nine Sprague‐Dawley female rats. They were orally given a single dose of DMBA (65 mg/Kg) at one month of age according to the breast cancer protocol. One group (I) was maintained with no other treatment for 24 weeks. The other group (II) was submitted to hands on treatment, three times a week, 15 minutes each, during 24 weeks. All the survival animals were ethically euthanized 24 weeks after carcinogenesis induction.The malignant breast tumors were evaluated by histopathology. Statistical analysis was carried out using a χ2 and Fisher's tests. The level of significance was set at P&lt; 0,05. There was no statistical difference between the morphology of both groups.This preliminary study suggests that CMT has no effect on breast carcinoma morphology, although further studies are required to evaluate an action on patient condition.