retinol-palmitate and Cell-Transformation--Neoplastic

In vitro changes of normal human keratinocytes (NHKs) derived from the oral mucosa after treatment with the chemical carcinogen 7,12 dimethylbenz[a]anthracene (DMBA; 5, 50, 200 ng/10 ml) were evaluated. NHKs were also treated with chemopreventive nutrient agents that previously had enhanced growth of epidermal and oral keratinocytes or suppressed growth of oral squamous cell carcinoma. These agents included the carotenoids beta-carotene and canthaxanthin and the retinoid retinyl palmitate (60 microM). Plating efficiency, growth in agarose (independent growth), viability [tetrazolium salt (MTT) assay], and proliferation ([3H]thymidine labeling) defined the growth of NHKs. The number of cornified cells and keratin expression (high-molecular-weight keratin) defined differentiation. gamma-Glutamyl transpeptidase, p53 expression, and tumorigenesis in mice defined oxidation and malignant transformation. Treatment with DMBA (50 ng/10 ml) was detected by autofluorescence; it produced an increase in pleomorphism and multinucleation and enhanced plating efficiency and the number of colonies grown in agarose. Chemopreventive treatment enhanced the number of colonies grown in agarose, but the MTT levels and [3H]thymidine incorporation-proliferation (24 h) were reduced. Chemopreventives also increased differentiation defined by the number of cornified cells and the expression of high-molecular-weight keratin-positive cells. Malignant transformation potential was depressed by reducing gamma-glutamyl transpeptidase and mutant p53 expression, whereas tumor suppressor p53 was enhanced. NHKs treated with DMBA and injected into nude mice (nu/nu: 1 x 10(6) cells/0.25 ml) produced tumor masses (3 of 3 animals), whereas the nutrient and DMBA groups produced smaller tumor masses, some with central ulcers (2 of 3 animals). Mock injection of untreated or nutrient-treated NHKs without DMBA treatment did not produce a tumor mass (0 of 3 animals). beta-Carotene, retinyl palmitate, and canthaxanthin increased differentiation and reduced transformation induced by DMBA in oral NHKs.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Adult; Animals; Anticarcinogenic Agents; beta Carotene; Canthaxanthin; Carcinogens; Cell Division; Cell Transformation, Neoplastic; Chromatography, High Pressure Liquid; Diterpenes; Flow Cytometry; Gene Expression Regulation; Humans; Immunohistochemistry; Keratinocytes; Male; Mice; Mice, Nude; Mouth Mucosa; Mouth Neoplasms; Retinyl Esters; Vitamin A

Leukoplakia, a white patch in the oral cavity or in the larynx that cannot be scraped off is a premalignant precursor of squamous cell carcinoma. It is tobacco-related and easily monitored. The rate of transformation of leukoplakia into invasive cancer is directly related to the degree of histologic abnormality. In the largest and longest study in the United States (mean follow-up, 7.2 years), the long-term transformation rate for dysplastic lesions was 36%. Surgical removal is considered the best therapy. However many patients operated on for oral leukoplakia later develop local relapses, new leukoplakias, or squamous cell carcinoma. Although leukoplakia lesions can show spontaneous regression, the response rate observed under treatment of retinoids is much greater.. In our study, high-dose retinyl palmitate was used for the first time on leukoplakias of the larynx. The study was conducted in two phases. In the first phase, all patients underwent induction therapy with a high dose of Retinyl Palmitate (A-Mulsin Hochkonzentrat, Mucos Pharma, Geretsried, Germany) 300.000 IU daily for the first week up to 1,500,000 IU daily in the fifth week. Patients whose lesions progressed during this period were withdrawn from the study. In the second phase, patients whose lesions responded to treatment or remained stable were then assigned to a maintenance therapy. The median duration of treatment was 104 days (range 15-272).. We observed a complete remission rate of 65% (20 out of 31 patients), a partial remission in 8 patients (26%) and a relaps in three patients (9%) during the next 15 months follow-up. Relapses were mainly seen in patients with a history of a carcinoma in situ or squamous cell carcinoma.. One of the main reasons for using retinyl palmitate in patients with larynx leukoplakia was to avoid general anesthesia in elderly patients who were considered as high risk patients for undergoing surgery. These results indicate that retinyl palmitate has substantial activity in larynx premalignancy. Because of its minor toxicity, it is an excellent candidate for a preventive agent for larynx cancer.

Topics: Aged; Aged, 80 and over; Anticarcinogenic Agents; Cell Transformation, Neoplastic; Diterpenes; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Humans; Laryngeal Neoplasms; Larynx; Leukoplakia; Male; Middle Aged; Retinyl Esters; Vitamin A

In 34 patients with HVP-infection of the cervix and in 40 patients with CIN III standardised biopsies were taken from the involved area and normal cervical epithelium for determination of the local concentration of retinylester. In all cases diagnosis was confirmed colposcopically, cytologically and by histology. HPV infection was confirmed by in situ hybridisation. Determination of retinylester was performed by HPLC. No significant difference of local retinyl-plamitate concentration was detectable in HPV infected versus normal tissue. Retinyl-palmitate concentration was extremely lower in CIN III compared with normal cervical epithelium and HPV-infected tissue. The determination of plasma level of retinol showed no significant difference between the two groups. So it can be presumed that the reduction of retinyl-palmitat in CIN III is a local process and a local supplementation of Vitamin A might contribute to the prevention of cervical neoplasia.

Topics: Anticarcinogenic Agents; Biopsy; Cell Transformation, Neoplastic; Cervix Uteri; Colposcopy; Diterpenes; Female; Humans; Neoplasm Staging; Papillomaviridae; Papillomavirus Infections; Retinyl Esters; Tumor Virus Infections; Uterine Cervical Dysplasia; Uterine Cervical Neoplasms; Vitamin A

The present study was designed to determine the effects of dietary 13-cis-retinoic acid and retinyl palmitate on mouse skin tumor promotion by 12-O-tetradecanoylphorbol-13-acetate (TPA). Female CD-1 mice were initiated with 150 nmol of 7,12-dimethylbenz(a)anthracene and promoted twice weekly with 8 nmol of TPA. Diets supplemented with retinyl palmitate to yield 60,000 or 200,000 IU or 700,000 for 5 wk followed by 350,000 IU per kg of diet (700,000/350,000) fed to mice during tumor promotion resulted in 9%, 37%, and 65% inhibition of the papilloma yield, respectively, at 21 wk of promotion. Although topical applications of 13-cis-retinoic acid have been almost as effective as retinoic acid in preventing the appearance of mouse skin tumors, dietary 13-cis-retinoic acid at 200,000 or 700,000 IU per kg of diet resulted in no reduction in papilloma yield but did result in a dose-dependent decrease in the tumor burden (weight of tumors per mouse). Therefore, dietary retinyl palmitate yielded a dose-dependent inhibition of the number and weight of tumors promoted by TPA, whereas dietary 13-cis-retinoic acid resulted in a decrease in weight but not in number of tumors promoted by TPA.

Topics: Administration, Cutaneous; Animals; Cell Transformation, Neoplastic; Diet; Diterpenes; Dose-Response Relationship, Drug; Female; Isotretinoin; Mice; Papilloma; Retinyl Esters; Skin; Skin Neoplasms; Tetradecanoylphorbol Acetate; Time Factors; Tretinoin; Vitamin A

Invasion of chick chorioallantoic membrane (CAM) organ cultures by rat 3Y1 cells transformed by the highly oncogenic human adenovirus type 12 (3Y1/12-10 cells) was inhibited by several retinoids tested. The anti-invasive activity of the retinoids was dependent on retinoid concentration and continuous (4 d) exposure of the CAM. The 50% retinoid dose (dose effective in achieving a response in half of the organ cultures) that inhibited invasion was 0.85 micrograms/ml of retinol palmitate, 0.39 micrograms/ml of retinoic acid, or 0.16 micrograms/ml of retinol acetate. This dose was of the same order of magnitude as that which induced CAM differentiation, and was three- to fourfold less than the dose that caused cytotoxic damage of CAM. In addition, the retinoids inhibited 3Y1/12-10 cell growth by approximately 40% at levels over 10-fold higher than those needed for anti-invasion activity. The findings suggest that the anti-invasive activity of retinoids was at least partly due to direct induction of cell differentiation of the CAM host tissue.

Topics: Adenoviruses, Human; Allantois; Animals; Cell Differentiation; Cell Division; Cell Transformation, Neoplastic; Cell Transformation, Viral; Chick Embryo; Chorion; Diterpenes; Extraembryonic Membranes; Neoplasm Invasiveness; Organ Culture Techniques; Rats; Retinoids; Retinyl Esters; Tretinoin; Vitamin A