Thymoquinone loaded calcium alginate and polyvinyl alcohol carrier inhibits the 7,12-dimethylbenz[a]anthracene-induced hamster oral cancer via the down-regulation of PI3K/AKT/mTOR signaling pathways.

Oral cancer is a multifactorial cancer that affects millions of peoples worldwide. The current exploration aimed to evaluate the mechanisms that thymoquinone nanoencapsulated carrier and its effects on 7,12-Dimethylbenz[a]anthracene (DMBA) stimulated hamster buccal pouch cancer in Syrian hamster model. Nanocarrier was characterized by SEM, TEM, FTIR analysis. The incidence of tumor, and biochemicals makers was studied through standard methods. The mRNA expression level of inflammatory markers NF-κBp50, NF-κBp65, and PI3K/AKT/mTOR markers in the buccal tissues of control and experimental animals were investigated through RT-PCR analysis. In thymoquinone (TQ) loaded calcium alginate and polyvinyl alcohol carrier (TQ/Ca-alg-PVA) no squamous cell carcinogenesis developed and others moderate dysplasia revealed differentiated form of hyperplasia and keratosis. In biochemical analyses with DMBA + TQ/Ca-alg-PVA (20 mg/kg bw) orally administered hamsters showed restored the antioxidants, detoxification, xenobiotic metabolising enzymes in DMBA induced plasma and oral tissues of hamsters. Further, mRNA expression level of NF-κBp50/p65 and PI3K/AKT/mTOR were upregulated in the DMBA alone painted hamster. In contrast, these expressions were down regulated in orally TQ/Ca-alg-PVA treated experimental animals. This ability more eligible to deregulate the inflammatory and PI3K/AKT/mTOR signaling pathway that proved it suppresses anti-invasion/metastasis activity during hamster buccal pouch carcinogenesis. From this study, we recommended that TQ/Ca-alg-PVA has documented as effective chemopreventive agents, in further many molecular machineries need to study.

Occupational Exposure to Polycyclic Aromatic Hydrocarbons and Elevated Cancer Incidence in Firefighters.

Cancer incidence appears to be higher amongst firefighters compared to the general population. Given that many cancers have an environmental component, their occupational exposure to products of carbon combustion such as polycyclic aromatic hydrocarbons (PAHs) is of concern. This is the first UK study identifying firefighters exposure to PAH carcinogens. Wipe samples were collected from skin (jaw, neck, hands), personal protective equipment of firefighters, and work environment (offices, fire stations and engines) in two UK Fire and Rescue Service Stations. Levels of 16 US Environmental Protection Agency (EPA) PAHs were quantified together with more potent carcinogens: 7,12-dimethylbenzo[a]anthracene, and 3-methylcholanthrene (3-MCA) (12 months post-initial testing). Cancer slope factors, used to estimate cancer risk, indicate a markedly elevated risk. PAH carcinogens including benzo[a]pyrene (B[a]P), 3-MCA, and 7,12-dimethylbenz[a]anthracene PAHs were determined on body surfaces (e.g., hands, throat), on PPE including helmets and clothing, and on work surfaces. The main exposure route would appear to be via skin absorption. These results suggest an urgent need to monitor exposures to firefighters in their occupational setting and conduct long-term follow-up regarding their health status.

7,12-dimethylbenz[a]anthracene interferes with the development of cultured mouse mandibular molars.

Clinical studies suggest that maternal smoking during pregnancy can reduce the crown size of the child's teeth. Delayed dental age compared with chronological age has also been reported in children whose parents smoke. Among the main components of tobacco smoke are nonhalogenated polycyclic aromatic hydrocarbons (PAHs), many of which are highly toxic. Humans are exposed to PAH compounds mainly via tobacco smoke and diet. The aim of our study was to investigate the effect of PAHs on tooth formation and the function of tooth-forming cells. We exposed mouse (NMRI) E18 mandibular first and second molar explants to 7,12-dimethylbenz[a]anthracene (DMBA), a toxic PAH compound, in organ culture for 7 or 12 days. DMBA concentrations used were 0.1, 0.5, 1, and 2 microM. The mesiodistal width of each first molar (12-day culture) was measured in stereomicroscopic images, and the teeth were analysed histologically. DMBA exposure significantly reduced the mesiodistal width of the first molars. DMBA impaired or delayed amelogenesis and dentinogenesis in both molars at the lowest concentration of 0.1 microM. DMBA affected enamel formation more severely than dentin formation and occasionally prevented amelogenesis completely. Elongation and polarization of ameloblasts were impaired, and blood vessel architecture of the dental papilla (future pulp) was altered. Cusps were thin and sharp. In line with the finding that maternal smoking during pregnancy has an adverse effect on child's tooth development, this study shows the toxic influence of PAHs on tooth development in vitro.

Combination of glycosphingosomes and liposomal doxorubicin shows increased activity against dimethyl-α-benzanthracene-induced fibrosarcoma in mice.

The present study aimed to assess the antitumor effect of glycosphingolipid-incorporated liposomes (glycosphingosomes) in combination with liposomal doxorubicin (Lip-Dox) in a mouse model of fibrosarcoma. Glycosphingosomes were prepared by incorporating glycosphingolipids isolated from Sphingomonas paucimobilis into the liposomes of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine, cholesterol, and cardiolipin. Tumors were induced by administering dimethyl-α-benzanthracene, and tumor-bearing mice were treated with various formulations of Dox, including free Dox, Lip-Dox, or glycosphingosomes + Lip-Dox. Mice were observed for 90 days to monitor their survival and tumor size. Free Dox, but not Lip-Dox or a combination of glycosphingosomes and Lip-Dox, caused the substantial depletion of leukocytes and significantly increased the levels of lactate dehydrogenase and creatinine kinase in mice. Tumor-bearing mice treated with a combination of glycosphingosomes and Lip-Dox showed restricted tumor growth and increased survival when compared to those treated with free Dox or Lip-Dox. The results of the present study suggest that a combination of glycosphingosomes and Lip-Dox may prove to be very effective in the treatment of tumors.

A comparison of the anticarcinogenic properties of four red wine polyphenols.

BACKGROUND: There has been growing interest in the analysis of certain polyphenols in wine, especially flavonoids, trihydroxystilbenes and phenolic acids, stimulated by intense research into their potential benefits to human health. One of their main properties in this regard is their antioxidant activity, which enables them to attenuate the development of atherosclerosis, inflammatory diseases, and cancer. METHODS: A two stage CD-1 mouse skin cancer model using 9,10-dimethyl-1,2-benzanthracene (DMBA) as initiator and phorbol 12-myristate 13-acetate (TPA) as promoter was employed to compare the antitumorigenic activities of one polyphenol from each of four different classes: flavanols [(+)-catechin], stilbenes (trans-resveratrol), flavonols (quercetin) and hydroxybenzoic acids (gallic acid). Animals were treated with specific polyphenols at doses ranging from 0 to 25 micromoles (dissolved in 200 microL acetone), twice a week for eighteen weeks. The solution was applied topically to the shaved dorsal region of each animal. The relative potencies of the polyphenols were compared by evaluating the percentage inhibition of tumor formation in individual mice and the number of mice developing one or more tumors with the different dose schedules. RESULTS: Probit analysis revealed that quercetin was the most (ED(50)<1 micromole) and gallic acid the least effective (ED(50) 5-10 micromoles). (+)-Catechin and trans-resveratrol were intermediate, with ED(50) values of 5 and 6 micromoles, respectively. CONCLUSION: We have shown recently that trans-resveratrol is absorbed much more efficiently than (+)-catechin and quercetin in humans after oral consumption. Taking this and the relative concentrations in red wine into account, together with the present results, we conclude that trans-resveratrol may be the most effective anticancer polyphenol present in red wine as consumed po by healthy human subjects.

Synthesis of PLGA nanoparticles of tea polyphenols and their strong in vivo protective effect against chemically induced DNA damage.

In spite of proficient results of several phytochemicals in preclinical settings, the conversion rate from bench to bedside is not very encouraging. Many reasons are attributed to this limited success, including inefficient systemic delivery and bioavailability under in vivo conditions. To achieve improved efficacy, polyphenolic constituents of black (theaflavin [TF]) and green (epigallocatechin-3-gallate [EGCG]) tea in poly(lactide-co-glycolide) nanoparticles (PLGA-NPs) were entrapped with entrapment efficacy of ~18% and 26%, respectively. Further, their preventive potential against 7,12-dimethylbenzanthracene (DMBA)-induced DNA damage in mouse skin using DNA alkaline unwinding assay was evaluated. Pretreatment (topically) of mouse skin with either TF or EGCG (100 µg/mouse) doses exhibits protection of 45.34% and 28.32%, respectively, against DMBA-induced DNA damage. However, pretreatment with TF-loaded PLGA-NPs protects against DNA damage 64.41% by 1/20th dose of bulk, 71.79% by 1/10th dose of bulk, and 72.46% by 1/5th dose of bulk. Similarly, 51.28% (1/20th of bulk), 57.63% (1/10th of bulk), and 63.14% (1/5th of bulk) prevention was noted using EGCG-loaded PLGA-NP doses. These results showed that tea polyphenol-loaded PLGA-NPs have ~30-fold dose-advantage than bulk TF or EGCG doses. Additionally, TF- or EGCG-loaded PLGA-NPs showed significant potential for induction of DNA repair genes (XRCC1, XRCC3, and ERCC3) and suppression of DNA damage responsive genes (p53, p21, MDM2, GADD45α, and COX-2) as compared with respective bulk TF or EGCG doses. Taken together, TF- or EGCG-loaded PLGA-NPs showed a superior ability to prevent DMBA-induced DNA damage at much lower concentrations, thus opening a new dimension in chemoprevention research.

Effects of two disiloxanes ALIS-409 and ALIS-421 on chemoprevention in model experiments.

Morpholino-disiloxane (ALIS-409) and piperazino-disiloxane (ALIS-421) compounds were developed as inhibitors of multidrug resistance of various types of cancer cells. In the present study, the effects of ALIS-409 and ALIS-421 compounds were investigated on cancer promotion and on co-existence of tumor and normal cells. The two compounds were evaluated for their inhibitory effects on Epstein-Barr virus immediate-early antigen (EBV-EA) expression induced by tetradecanoyl-phorbol-acetate (TPA) in Raji cell cultures. The method is known as a primary screening test for antitumor effect, below the (IC50) concentration. ALIS-409 was more effective in inhibiting EBV-EA (100 µg/ml) and tumor promotion, than ALIS-421, in the concentration range up to 1000 µg/ml. However, neither of the compounds were able to reduce tumor promotion significantly, expressed as inhibition of TPA-induced tumor antigen activation. Based on the in vitro results, the two disiloxanes were investigated in vivo for their effects on mouse skin tumors in a two-stage mouse skin carcinogenesis study. The application of dimethyl-benzanthracene (DMBA; 390 nmol) as a tumor initiator was followed by exposure to TPA (1.7 nmol/l) as a tumor promoter. The experiments showed that ALIS-409 at a concentration of 85 nmol/l had a weak EBV-EA inhibitory effect in vitro and a moderate antitumor activity, compared to the positive control of DMBA plus TPA-treated mice. Flow cytometry by differential staining demonstrated interactions in co-cultures of MCF7 breast cancer and MRC5 human lung fibroblasts. The growth rate of tumor cells in mixed populations of MCF7 breast cancer and MRC5 normal fibroblast cells was reduced in the presence of ALIS-409, as compared to the control non-treated cell populations. The two disiloxanes were moderately-effective in chemoprevention in DMBA-induced and TPA-promoted in vivo tumor formation. Authors suggest that the inhibition of tumor cell and fibroblast interaction by ALIS409 might have some perspective in the development of anti-stromal therapy.

Tamoxifen-loaded novel liposomal formulations: evaluation of anticancer activity on DMBA-TPA induced mouse skin carcinogenesis.

PURPOSE: Tamoxifen (TAM) is a non-steroidal estrogen receptor modulator known for its anticancer activity. Apart from marked breast cancer activity, this drug has also shown potential in treating other types of cancers including skin cancers. TAM is reported to be associated with serious side effects primarily due to its systemic distribution. The localized delivery of this drug in this regard would be highly beneficial with respect to safety as well as efficacy. METHODS: In the current studies, an endeavor has been made to investigate the efficacy of topically applied liposome-encapsulated TAM on skin cancer model. The drug was encapsulated in phospholipid-based vesicular systems viz. conventional liposomes and elastic liposomes. Incidence of papillomas and histopathological examination were employed to determine the efficacy of the tested formulations. RESULTS: The results demonstrated carrier-dependent strong inhibition of skin carcinogenesis with encapsulated drug vis-à-vis drug in the solution form. The encouraging findings from the current work construe immense potential of the TAM-loaded liposomal systems in the management of skin cancer.

Lack of skin carcinogenicity of topically applied titanium dioxide nanoparticles in the mouse.

This study was conducted to examine the post-initiation carcinogenic potential of coated and uncoated titanium dioxide nanoparticles (CTDN and UCTDN) using a mouse medium-term skin carcinogenesis bioassay. For this purpose, 5, 10 and 20mg/animal doses of CTDN or UCTDN were applied to mouse skin in the post-initiation phase (up to 20 weeks) in a two-stage skin carcinogenesis model using 7 week old CD1 (ICR) female mice. 7,12-dimethylbenz[a]anthracene (DMBA) and 12-o-tetradecanoylphorbol 13-acetate (TPA) were used as the initiator and a positive control promoter, respectively. Pentalan 408 served as a vehicle control. No changes in survival rate, general condition and body weight related to the test materials were observed. On macroscopic observation, 1-2 nodules/group on the skin were observed in each group applied CTDN and UCTDN as well as the control group after DMBA initiation. The nodules were histopathologically diagnosed as squamous cell hyperplasia, sebaceous gland hyperplasia, squamous cell papilloma and keratoacanthoma. CTDN and UCTDN experiments, while enlargement of the mandibular, pancreatic, lumbar region and inguinofemoral lymph nodes, spleen and thymus was observed in mice given 5 and 10mg but not 20mg, the lack of dose-dependence suggests no biological significance. In the present study, CTDN and UCTDN applied in post-initiation stages at doses of up to 20mg/mouse did not increase the development of nodules, and thus it was concluded that titanium dioxide nanoparticles do not possess post-initiation potential for mouse skin carcinogenesis.

Potential of diallyl sulfide bearing pH-sensitive liposomes in chemoprevention against DMBA-induced skin papilloma.

Diallyl sulfide (DAS), an active component of garlic, possesses strong anti-neoplastic properties against various forms of cancer. In the present study, we have evaluated chemo-preventive effects of liposomized DAS (conventional egg PC and pH-sensitive liposomes) against DMBA-induced skin papilloma. Various liposome-based novel formulations of DAS (250 microg/mouse) were applied topically, after one hour of exposure to DMBA (52 microg/mouse/dose), to the animals. The animals were treated thrice weekly for the total period of 12 weeks. The efficacy of the various liposomal formulations of DAS was evaluated on the basis of parameters such as incidence of tumorogenesis and total numbers and sizes of induced tumor nodules. The liposomized DAS formulations also were assessed for their effect on the expression of p53wt, p53mut, and p21/Waf1. The results of the present study showed that liposomized DAS could effectively delay the onset of tumorogenesis and reduce the cumulative numbers and sizes of tumor papillomas in treated mice. Treatment of DMBA-exposed animals with the liposomal formulation of DAS ensued in upregulation of p53wt and p21/Waf1, while levels of p53mut expression reduced down. The promising chemo-preventive nature of liposomal DAS may form the basis for establishing effective means of controlling various forms of cancer, including skin papilloma.

Cholestyramine promotes 7,12-dimethylbenzanthracene induced mammary cancer in Wistar rats.

The promotion of 7,12-dimethylbenzanthracene (DMBA) induced mammary cancer in Wistar rats by a 4% cholestyramine (CHST) diet was investigated. The rats, 50 days of age, were divided into six groups. First two groups were given an intragastric dose of 0.8 ml of corn oil whereas the remaining four groups were given a single intragastric dose of 5 mg of DMBA dissolved in 0.8 ml of corn oil. After 1 week on laboratory chow the first two groups and two groups treated with DMBA were fed a control diet and the two remaining groups treated with DMBA were fed a 4% CHST diet. Half the animals were killed at 100 days and the remainder at 200 days. A detailed histologic examination of grossly normal mammary tissue as well as any tumour mass was made for each rat. The serum lipids were extracted and the individual neutral lipid composition was determined. In rats treated with DMBA and fed a 4% CHST diet, the incidence of malignant tumours increased by 5 fold, and the tumour weight by 12 fold. In addition, the serum total lipids, cholesterol esters and triglycerides decreased significantly when compared with rats fed a control diet. These results suggest that CHST diet promotes DMBA induced mammary cancers in Wistar rats.

Final report on the safety assessment of PEG-6, -8, and -20 sorbitan beeswax.

Polyethylene Glycol (PEG)-6, -8, and -20 Sorbitan Beeswax are ethoxylated derivatives of Beeswax that function as surfactants in cosmetic formulations. Only PEG-20 Sorbitan Beeswax is currently reported to be used, at concentrations up to 11%. Few data on the PEGs Sorbitan Beeswax ingredients were available. This safety assessment relied upon the available data from previous safety assessments of Beeswax, Synthetic Beeswax, Sorbitan Esters, PEGs, and PEG Sorbitan fatty acid esters, also known as Polysorbates. The ester linkage of PEG Sorbitan fatty acid esters was hydrolyzed after oral administration, and the PEG Sorbitan moiety was poorly absorbed from the gastrointestinal tract. Sorbitan Stearate was hydrolyzed to stearic acid and anhydrides of sorbitol in the rat. PEGs are readily absorbed through damaged skin and are associated with contact dermatitis and systemic toxicity in burn patients. PEGs were not sensitizing to normal skin. PEGs did not cause reproductive toxicity, nor were tested PEGs mutagenic or carcinogenic. Sorbitol was not a reproductive or developmental toxin in multigenerational studies in rats. Neither Beeswax nor Synthetic Beeswax produced significant acute animal toxicity, ocular irritation, skin irritation, or skin sensitization. Polysorbates produced no acute or long-term effects, were generally not irritating or sensitizing, and were noncarcinogenic, although studies did demonstrate enhancement of the activity of chemical carcinogens. Sorbitan fatty acid esters were relatively nontoxic via ingestion, generally were not skin irritants or sensitizers, and were not mutagenic or carcinogenic. Sorbitan Laurate was a cocarcinogen in a mouse skin-painting study. PEG-6 Sorbitan Beeswax delivered via a stomach tube was nontoxic in rats in acute studies. Undiluted PEG-6 Sorbitan Beeswax was nonirritating to the eyes of rabbits and was non-irritating to intact and abraded skin of rabbits. PEG-20 Sorbitan Beeswax was only minimally irritating to rabbit eyes at concentrations as high as 30%, and was not a significant skin irritant in rabbits exposed to a product with PEG-20 Sorbitan Beeswax at 2%. In clinical tests, PEG-6 and -20 Sorbitan Beeswax at concentrations up to 3% were only minimally irritating and were nonsensitizers. Careful consideration was made of the data on the cocarcinogenesis, but the high exposure levels, high frequency of exposure, and absence of a dose-response led to the conclusion that there was not a cocarcinogenesis risk with the use of these ingredients in cosmetic formulations. Accordingly, these ingredients were considered safe for use in cosmetic formulations under the present practices of use.

Evaluation of Pluronic Polyol F127 as a vehicle for petroleum hydrocarbons in the Salmonella/microsomal assay.

Complex hydrocarbon mixtures have proven difficult to evaluate in in vitro mutagenicity assays owing to their insolubility in aqueous environments. Pluronic Polyol F127 (BASF Wyandotte, Parsippany, NJ), prepared as a 50% (w/w) solution in absolute ethanol, proved effective in emulsifying various petroleum hydrocarbon fractions. Its effectiveness in the Salmonella/microsomal assay was evaluated using model solutions each comprising a polycyclic aromatic hydrocarbon (PAH) dissolved in mineral oil. The PAHs used were benzo(a)pyrene, 3-methylcholanthrene, and 7,12-dimethylbenz(a)anthracene. Model solutions were evaluated neat and as emulsions with the Pluronic F127 solution or Tween 80. Similar levels of each PAH were prepared in dimethyl sulfoxide (DMSO) for comparison. Cytotoxicity and mutagenesis were evaluated in the preincubation technique using strain TA97. Little or no cytotoxicity or mutagenesis was evident for model solutions tested neat. However, emulsification of these PAH-laden mixtures with the Pluronic F127 solution yielded cytotoxic and mutagenic responses similar to, or greater than, those observed for PAHs delivered in DMSO. Model mixtures emulsified with Tween 80 were less active. Study results demonstrate that Pluronic F127, prepared as a 50% (w/w) solution in absolute ethanol, is an effective vehicle for evaluating the mutagenic potential of complex hydrocarbon mixtures containing PAHs in the Salmonella/microsomal assay. Since PAHs are a class of insoluble hydrocarbons, the results also suggest the potential usefulness of the Pluronic F127 solution to detect the mutagenicity of other insoluble hydrocarbons and hydrocarbon mixtures.