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Results for “retinoids”

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At least 19 recordsLinked to original sources

PubMed1979

[Side effects of oral retinoid Ro 10-9359 on the unaffected skin of psoriatic patients: retinoid dermatitis].

Dermatitis occurring as a side effect in psoriatic patients during oral administration of the retinoid acid derivative Ro 10-9359 is described. This so-called retinoid dermatitis exhibits a characteristic disseminated pattern. Sites of predilection are the face, the exterior surface of the upper and the interior surface of the lower arms, the superior thoracic aperture, the back of the hands and the flanks. The lesions present as follicular papules and/or vesicles. The histological picture is that of acute non-specific dermatitis. This retinoid dermatitis was observed in 9 our of 23 patients (39%) treated with Ro 10-9359. Other side effect such as erythema, desquamation, itching and, rarely, a burning sensation showed the same distribution. The characteristic dermatitis, as well as the other side effects mentioned, occur dose-dependently within the normal therapeutic range of Ro 10-9359 for psoriasis (0.5--1 mg/kg bodyweight daily).

Administration, Oral↗

PubMed2025

Targeting PRAME directly or via EZH2 inhibition overcomes retinoid resistance and represents a novel therapy for keratinocyte carcinoma.

Retinoids have demonstrated efficacy as preventative/treatment agents for keratinocyte carcinomas (KCs): basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (SCC). However, retinoid resistance mechanisms limit the efficacy of these compounds. A subset of KCs expresses Preferentially Expressed Antigen in Melanoma (PRAME): a retinoid signaling corepressor. PRAME is proposed to repress retinoid signaling by guiding enhancer of zeste homolog 2 (EZH2) to retinoic acid response elements (RARE) in promoters. We investigated the effects of PRAME on KC pathogenesis and retinoid response. High-PRAME expression in tumors was negatively correlated with epidermal differentiation gene signatures. PRAME overexpression downregulated epidermal differentiation gene signatures and impaired differentiation in 3D culture. PRAME overexpression attenuated retinoid-induced RARE activation, growth suppression, and differentiation responses. Conversely, low-PRAME tumors and PRAME-depleted KC cells demonstrated enriched epidermal differentiation gene signatures. PRAME downregulation restored retinoid-induced RARE activation, growth suppression, keratinization in SCC, and cell death signaling in BCC. Furthermore, combined retinoid and EZH2 inhibitor treatment augmented RARE activation and suppressed PRAME-expressing KC cell growth. Hence, PRAME confers retinoid resistance in KC, which may be overcome by EZH2 inhibition.

Enhancer of Zeste Homolog 2 Protein↗

PubMed1976

Prevention of chemical carcinogenesis by vitamin A and its synthetic analogs (retinoids).

An approach to chemoprevention of common forms of epithelial cancer, during the period of preneoplasia, is described. Vitamin A and its synthetic analogs (retinoids) are potent agents for control of cell differentiation in many epithelial tissues. Direct effects of retinoids on normal and preneoplastic cell differentiation can be measured in organ culture. In experimental animals, deficiency of dietary retinoids enhances susceptibility to chemical carcinogenesis. Natural retinoids, fed at high dietary levels, have some ability to prevent chemical carcinogenesis in epithelial tissues of bronchi, trachea, stomach, uterus, and skin of experimental animals. However, natural retinoids have limited usefulness for chemoprevention of cancer because of inadequate tissue distribution and excessive toxicity. Synthetic retinoids have been made and shown to be more potent and less toxic for prevention of cancer in animals. Several structural modifications of the ring and terminal portions of the retinoid molecule have significant biological activity; modification of the side chain has been more difficult. The potential future usefulness of this approach to cancer prevention in man will depend on further synthetic modification of the retinoid molecule.

Animals↗

PubMed2026

Retinoid dynamics in immune cells during age-related diseases.

Retinoids comprise vitamin A and its structurally related natural and synthetic derivatives. Retinoid dynamics involves multiple retinoid forms, carrier proteins, and enzymes that orchestrate the absorption, transport, storage and biotransformation of dietary vitamin A. Beyond their canonical metabolic functions, metabolites and proteins involved in retinoid metabolism also play distinct roles in signal transduction and transcriptome reprogramming, broadening the mechanisms that influence immune cell fate decisions. Age‑related changes in retinoid bioavailability and signaling intensity alter immune cell polarization and function, thereby contributing to the pathogenesis of chronic inflammation in neurodegenerative diseases, cardiovascular diseases, osteoarthritis, and other age-related diseases. In this review, we focus on age-related alterations in the retinoid metabolic pathway and their impact on inflammation and the progression of age-related diseases. This review highlights the pivotal role of retinoid metabolism in anti-ageing interventions and considers future directions and challenges in this field.

Humans↗

PubMed1979

Retinoid prevents mammary gland transformation by carcinogenic hydrocarbon in whole-organ culture.

The mouse mammary gland in whole-organ culture, an in vitro system that is capable of alveolar development, differentiation, involution, and oncogenic transformation, has been used to examine the effects of the retinoid 2-retinylidene-5,5-dimethyl-1,3-cyclohexanedione (retinylidene dimedone) on epithelial transformation by a low concentration (10 nM) of the carcinogen 7,12-dimethylbenz[a]anthracene. The retinoid significantly prevented mammary gland transformation only when administered after the carcinogen. In addition, the phenotypes of the early transformed state of the mammary gland were suppressed for 20 days after removal of the retinoid. The retinoid was effective during both mammary alveolar development and regression in culture at concentrations as low as 1 nM, and itself had no significant transforming or cytotoxic activity. Mammary glands treated with both the carcinogen and the retinoid resembled, at the microscopic level, those given the solvent (dimethyl sulfoxide) only. The mouse mammary gland in whole-organ culture provides a promising model system in which to study the actions by which retinoids prevent and suppress the chemical transformation in vitro and oncogenesis in vivo of epithelial cells in general and of mammary gland in particular. The present findings support the suggestion that a search for suitable retinoids as chemopreventive agents against human breast cancer is warranted. This model system may be useful as initial indicator in that search.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1978

Retinoids, a new class of compounds with prophylactic and therapeutic activities in oncology and dermatology.

A review of recent investigations in the retinoid field is presented. Retinoic acid exerts a prophylactic and a therapeutic effect on chemically induced benign and malignant epithelial tumors in mice. In clinical studies positive therapeutic results have been obtained in patients with preneoplastic and neoplastic epithelial lesions. However, treatment with retinoic acid is limited by serious side effects (hypervitaminosis A syndrome). Therefore, the synthesis of analogs of retinoic acid (retinoids) possessing a more favorable therapeutic ratio has been initiated. Among a large series of synthesized compounds, certain aromatic analogs proved to have a particularly favorable therapeutic ratio. The structure-activity relationship of the most active retinoids is discussed including some biological data concerning prophylaxis and therapy of epithelial tumors. The total synthesis of retinoids according to various building schemes is discussed in detail. Methods for the synthesis of the cyclic end group, of the polyene chain component, and of the full retinoid skeleton are described. Metabolic studies of retinoic acid and of the most active retinoid, as well as the synthesis of some isolated metabolites are outlined. Suggestions concerning the mechanism of action of retinoids are made. Some clinical results on the treatment of acne, psoriasis and precancerous conditions are reported.

Animals↗

PubMed1978

Assay of retinoids in biological samples by reverse-phase high-pressure liquid chromatography.

A separation procedure for retinoids based on reversephase high-pressure liquid chromatography with solvent mixtures of acetonitrile and water is described. The method may be applied to the screening of synthetic retinoids, which have potential for use in the prevention of cancer. It is easily adapted to a variety of biological samples and can be applied to other conventional retinoid assays in liver and plasma, detecting as little as 1 nmol retinyl esters and less than 0.3 nmol retinol per g tissue. The one-step chromatography results in separation and simultaneous determination of many of the synthetic retinoids and all of the natural retinoids, including the retinyl esters that are separated into their major fatty acid components. The method has been applied to the analysis of retinoid levels in the liver and intestine of vitamin A-deficient hamsters following a p.o. dose (0.5 mg/day for 2 days) of retinyl acetate or of a synthetic vitamin A analog and is predictive of the degree to which various synthetic retinoids can be converted to retinol and stored in the liver as retinyl esters. Because of its speed, excellent recoveries, and high resolution, the method offers significant advantages over previous, more lengthy procedures.

Animals↗

PubMed1979

[Beneficial effect of oral retinoid in psoriatic hyperproliferation. Autoradiographic studies on involved and non involved skin (author's transl)].

In 16 patients with generalized psoriasis treated with oral retinoid (Ro 10-9359; 1 mg/kg body weight/(day) autoradiographic studies were performed before, and 24 h, 48 h, 1 week and 3 weeks after beginning of treatment on involved and non involved epidermis. During the first week no significant changes of all cellular parameters were found. However, after 3 weeks of continuing medication the increased 3H-thymidine labelling index was markedly lowered and the prolonged DNA synthesis time was shortened; whereas, the cell cycle time remained unaffected. The findings revealed that oral retinoid has a distinct influence on epidermal cell proliferation towards normalization in both involved and non involved epidermis in psoriasis. The time needed for this effect indicates that the drug does not directly interfere with the cell cycle. It seems reasonable, therefore, to combine oral retinoids as a basic adjuvant drug with other antipsoriatic techniques, such as retinoid + anthralin, retinoid + PUVA, retinoid + UVB.

Cell Cycle↗

PubMed1979

Chemoprevention of cancer with retinoids.

The importance of retinoids for chemoprevention of cancer has received further emphasis with the finding that retinoids can suppress in vitro expression of the malignant phenotype, whether it be caused by chemical carcinogens, radiation, or viral transforming factors. Retinoids have been found to be potent inhibitors of the tumor-promoting effects of phorbol esters. Further advances in the chemistry of synthetic retinoids have led to the development of new agents that show less toxicity and better targeting to specific organ sites than natural retinoids. Synthetic retinoids have been particularly useful for prevention of bladder and breast cancer in experimental animals.

Animals↗

PubMed1979

Effect of retinoids on the differentiation of chick embryo metatarsal skin explants.

Twelve retinoids were evaluated in organ culture for activity in modulating epithelial differentiation of metatarsal skin explants from 13-day chick embryos. The epithelium differentiated into a squamous, keratinizing epidermis; but, in the presence of active retinoids, keratinization was inhibited, and a mucous metaplasia developed. The methyl-keto and 1-methoxyethyl cyclopentenyl analogs of retinoic acid were about tenfold more effective than retinoic acid in altering epithelial differentiation. The dichlorophenyl analog exhibited about the same activity as retinoic acid. The following analogs were one-half to one-third as effective as retinoic acid in inhibiting keratinization: the chlorotrimethylphenyl analog of retinoic acid and the 13-cis, 10-fluoro analog of trimethylmethoxyphenyl methyl retinoate. The other 7 retinoids were essentially not active at the concentration tested (1.4--2.0 x 10(-5) M). The activity of synthetic retinoids in altering epithelial differentiation may be related to their ability to affect or treat epithelial lesions provided that modification of the retinoid molecule can enhance its activity and decrease toxicity.

Animals↗

PubMed1976

Effect of aromatic retinoids on rat chondrosarcoma glycosaminoglycan biosynthesis.

Synthetic aromatic analogs of retinoic acid were administered i.p. and p.o. to Fischer F344 rats bearing a transplantable chondrosarcoma. 35CO4 incorporation into glycosaminoglycans were compared for neoplastic and normal cartilage explants after removal from animals given various analogs. There was a direct relationship between [35S]glycosaminoglycan synthesis by chondrosarcoma chondrocytes and inhibition of tumor growth. The degree of inhibition of [35S]glycosaminoglycan synthesis in the neoplastic cartilage was dependent on the dose of the retinoid administered. At 20-mg/kg/day doses of retinoid for 4 weeks, 35SO4 incorporated into glycosaminoglycan by treated tumor explants was reduced as much as 95%. There was no reduction of [35S] glycosaminoglycan produced in normal costal cartilage of the same animals. Retinoid treatment of 20-mg/kg/day doses for 4 weeks resulted in a 75% reduction in glycosaminoglycan per mg of chondrosarcoma; there was no reduction in costal cartilage glycosaminoglycan. Retinoid (10- to 20-mg/kg/day doses) elevated collagen levels per mg of chondrosarcoma but had no effect on costal cartilage collagen. Combined in vitro and in vivo studies showed that retinoid administration modified neoplastic chondrocyte function but had no measurable effect on normal chondrocyte function.

Animals↗

PubMed1979

N-(4-Hydroxyphenyl)retinamide, a new retinoid for prevention of breast cancer in the rat.

The synethesis of a new retinoid, N-(4-hydroxyphenyl)-all-trans-retinamide, which has useful biological properties, is described. This retinoid was more potent than retinyl acetate in reversing keratinization caused by retinoid deficiency in tracheal organ culture. It was markedly less toxic than retinyl acetate when fed p.o. to rats over 2-week or 6-month periods. It was an effective agent for inhibition of the development of breast cancer induced in rats by N-nitroso-N-methylurea, although it was not as potent as retinyl acetate in this regard. However, the lesser toxicity of 4-hydroxyphenylretinamide makes it a superior agent for prevention of breast cancer. High-pressure liquid chromatographic analyses of liver and breast extracts from rats treated for 6 months with retinoids show the pharmacokinetic basis for the superiority of 4-hydroxyphenylretinamide; this retinoid and its metabolites were found in high concentrations in breast tissue, without any measurable accumulation in the liver or evident liver toxicity. In contrast, chronic feeding of retinyl acetate caused marked deposition of retinyl esters in the liver and severe hepatotoxicity. Whole mounts of rat mammary glands, made after chronic feeding of 4-hydroxyphenylretinamide, showed that it had a marked antiproliferative effect on mammary epithelium.

Animals↗

PubMed1979

[Hair growth, liver function and light sensitivity during oral retinoid therapy for psoriasis (author's transl)].

In a multicentre, cooperative study into the treatment of extensive psoriasis with a new aromatic retinoid (Ro 10--9359) trichogram, liver function tests and the light erythema threshold were investigated. In some of the patients hair loss occurred, usually in the fifth to eighth week after a total dose of 1.9 g retinoid. In all cases this improved an average of six weeks after dose reduction or cessation of treatment. The trichogram in 27 patients showed a diffuse toxic hair loss. In 70% the effluvium was telogenic, in 22% telogen-dystrophic. GPT, GOT, alkaline phosphatase and prothrombin index showed no significant alterations during retinoid treatment. However, in individual cases there was a rise in GOT and GPT up to 80 U/l. Furthermore there was a statistical tendency in rising bilirubin levels. Finally there was no evidence for an increase in light sensitivity after three weeks of retinoid treatment. Measurement of the erythema threshold showed rather more a reduction in light sensitivity under treatment.

Alanine Transaminase↗

PubMed1977

Reversal by vitamin A analogues (retinoids) of hyperplasia induced by N-methyl-N'-nitro-N-nitrosoguanidine in mouse prostate organ cultures.

The antihyperplastic activity of beta-retinoic acid (RA) and nine synthetic analogues (retinoids) was examined in organ cultures of mouse prostate made hyperplastic by treatment with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). After 8 or 10 days, when most explants developed hyperplasia, the carcinogen was withdrawn and explants were incubated in control medium and medium containing different concentrations of a retinoid. The antimitotic activity of retinoids was compared with that of RA. Different retinoids produced variable degrees of mitotic inhibition in the hyperplastic prostate epithelium. The methylketo cyclopentenyl and 1-methoxyethyl cyclopentenyl analogues of RA were at least 50-fold more active than RA in reversing MNNG-induced hyperplasia. The trimethylmethoxyphenyl analogue of RA and retinyl methyl ether were significantly more active than RA. Three analogues, N-acetyiretinylamine, retinal acetyl hydrazone, and retinal oxime, were as active as RA. The chlorotrimethylphenyl analogue showed less activity than RA, and alpha-retinyl acetate was completely devoid of mitotic inhibitory activity.

Cell Division↗

PubMed1979

[Results of systemic treatment of lichen planus with a new aromatic retinoid (RO 10-9359) (author's transl)].

24 patients suffering from generalized lichen planus were treated systemically with a aromatic retinoid (RO 10-9359). Initially a dose of 100 mg retinoid per day was administered for 2 to 3 weeks, then the daily intake was reduced slowly. The average duration of treatment was 72 days. This therapy produced a significant improvement in all patients. Lesions recurred during reduction of administered retinoid in 3 patients and after stopping treatment in 5 cases. Initially side effects consisted of cheilitis and exfoliation of the skin over the palmar and plantar regions; later 50% of the patients developed an effluvium. The results of the present study indicate that the aromatic retinoid can be considered as an alternative drug to systemic steroids in the treatment of lichen planus.

Dose-Response Relationship, Drug↗

PubMed1979

Inhibition of human melanoma colony formation by retinoids.

We studied the effects of retinoids on the in vitro survival of melanoma colony-forming cells in biopsies obtained from ten patients with metastatic melanoma. The results indicate that specific retinoids reduce the ability of fresh human melanoma cells to form colonies in soft agar. The retinoids studied had differential effects on the survival of clonogenic melanoma cells, and these effects vary from patient to patient. The data provide support for the clinical trial of selected retinoids in micrometastatic and advanced melanoma.

Cell Division↗

PubMed1978

[Retinoid PUVA (RePUVA): systemic combination therapy in psoriasis].

RePUVA is a new therapeutic approach in psoriasis, consisting in oral administration of a retinoid derivative and systemic PUVA treatment. The retinoid (Ro 10-9359) was given daily (50--75 mg) before, simultaneously and, before and simultaneously with PUVA. The overall response was 73%; however, 14 patients resistant to previous standard PUVA treatment also responded surprisingly well to RePUVA. If PUVA-resistent patients were excluded, the overall response was 82.6%. The mean number of treatments required for clearing was 19.4 +/- 6.1, the mean total UVA-dose 57.9 +/- 32.3 J/cm2 and the mean duration of treatment was 55.4 +/- 14.1 days, including pretreatment with retinoid. It seems that RePUVA may be most successful if the retinoid is given before and with PUVA: 33.7 +/- 8.7 J/cm2 in 17.0 +/- 4.7 sessions were then required for clearing. Compared with previous results of our group and recent publications these findings indicate that the RePUVA schedule may reduce the duration of treatment and the total UVA-dose and, therefore, the possible long-term hazards of PUVA management. In addition, RePUVA can be successfully applied in patients resistant to standard PUVA.

Coumarins↗

PubMed1979

Retinoids and cancer.

The early and recent investigations in the field of retinoids and cancer are reviewed. The retinoids, including natural vitamin A compounds and their synthetic analogs, present a new class of substances exerting a prophylactic and a therapeutic effect both in certain experimental tumor models and in certain clinical conditions of preneoplastic and neoplastic lesions. Because of a particular physiological mechanism of action, the retinoids offer a new approach to the cancer problem, which is different from those of surgery, X-ray therapy, conventional chemotherapy, and immunotherapy.

Animals↗