retinol-acetate and Skin-Neoplasms

To determine the chemotherapeutic effect of retinoids on albino mouse skin.. Eighty albino mice were selected for this study and were divided into four groups (A-D, 20 mice in each group). 7,12-Dimethylbenz(a)anthracene (DMBA) and tetradecanoylphorbal-13-acetate (TPA) were given for 15 weeks to produce tumors. Retinoids were given topically and orally after the development of tumors for the following 15 weeks.. Of the 80 mice, 69 (86.25%) developed different types of lesion and 11 (13.75%) remained lesion free. Of the 69 mice that developed lesions, 50 (62.50%) developed benign lesions and 19 (23.75%) developed malignant lesions. In all groups of mice, treatment with retinoids was effective against all benign lesions and the early stages of carcinogenesis of the skin. The chemotherapeutic effect against malignant tumors was not satisfactory.. This study demonstrates that retinoids are effective as chemopreventive agents in premalignant lesions of the skin, but have a very weak chemotherapeutic role in malignant neoplasms. If retinoids are given at an early stage, they can cause regression of premalignant lesions of the skin. They are best administered both orally and parenterally. These agents should be recommended as they reduce the potential effects of carcinogenesis.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Antineoplastic Agents; Diterpenes; Isotretinoin; Mice; Precancerous Conditions; Retinyl Esters; Skin Neoplasms; Tetradecanoylphorbol Acetate; Vitamin A

Rat skin was exposed to the plateau region of the 1.0 GeV/nucleon 56Fe beam at the Brookhaven AGS. Rats were irradiated or not with single of split doses of 56Fe or argon; some 56Fe-exposed rats were fed 250 ppm retinyl acetate continuously in the lab chow beginning 1 week before irradiation. All lesions were noted, photographed and identified for eventual histological diagnosis. The preponderance of the tumors so far are fibromas. The data show that single doses of 56Fe ions are 2 or 3 fold more effective than argon in producing tumors at 4.5 Gy but are about equally effective at 3.0 Gy and 9.0 Gy. The presence of 250 ppm retinyl acetate in the lab chow reduced the incidence of tumors by about 50-60% in comparison to groups exposed only to the radiation. These are preliminary findings based on only about one-fourth the eventual number of tumors expected.

Topics: Animals; Anticarcinogenic Agents; Diterpenes; Dose-Response Relationship, Radiation; Fibroma; Heavy Ions; Iron; Linear Energy Transfer; Neoplasms, Radiation-Induced; Rats; Retinyl Esters; Skin; Skin Neoplasms; Synchrotrons; Vitamin A

Effects of retinoids and inhibitors of arachidonic acid metabolism on tumor-promoter-induced soft agar colony formation of mouse epidermal cells and rat bladder cells were evaluated. Topical application of retinoic acid, an anti-tumor-promoter, to female SENCAR mouse skin inhibited 12-O-tetradecanoylphorbol-13-acetate-induced soft agar colony formation of mouse epidermal cells, an event proposed to be essential for tumor promotion. Effects of dietary retinyl acetate, nordihydroguaiaretic acid (NDGA) and quinacrine hydrochloride on colony formation of rat bladder cells were then examined. Male Fischer 344 rats were given 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine for 3 weeks, followed immediately by the administration for 9 weeks of 5% sodium saccharin supplemented with or without 0.05% retinyl acetate, 0.1% NDGA or 0.01% quinacrine hydrochloride. Saccharin-induced colony growth was significantly inhibited by the administration of retinyl acetate or NDGA, suggesting that these two agents have anti-tumor-promoting effects on rat bladder carcinogenesis. Thus, the colony-forming assay might be useful for early detection of anti-tumor-promoters of skin and bladder.

Topics: Animals; Arachidonic Acid; Arachidonic Acids; Colony-Forming Units Assay; Diterpenes; Epidermis; Female; Male; Masoprocol; Mice; Quinacrine; Rats; Rats, Inbred F344; Retinoids; Retinyl Esters; Saccharin; Skin Neoplasms; Tetradecanoylphorbol Acetate; Tumor Stem Cell Assay; Urinary Bladder Neoplasms; Vitamin A

The cell-differentiating agents (inducers) dimethylacetamide, dimethylurea and tetramethylurea significantly lowered the yields and/or incidences of total tumors, benign plaques, benign hyperkeratotic lesions and advanced tumors promoted by retinyl acetate or croton oil after initiation by 7,12-dimethylbenz(a)anthracene. The percentage of plaques was increased by the inducers suggesting that they inhibited progression of plaques to more advanced tumors. These results suggest that topical application of inducers might have therapeutic potential in epidermal carcinoma.

Topics: Acetamides; Animals; Cell Differentiation; Cricetinae; Croton Oil; Diterpenes; Female; Mesocricetus; Methylurea Compounds; Neoplasms, Experimental; Precancerous Conditions; Retinyl Esters; Skin Neoplasms; Vitamin A