retinaldehyde and Neoplasms

Topics: Animals; Carrier Proteins; Cell Differentiation; Chemical Phenomena; Chemistry; Epithelium; Female; Growth; Humans; Isomerism; Male; Neoplasms; Pregnancy; Receptors, Retinoic Acid; Reproduction; Retinal Pigments; Retinaldehyde; Retinol-Binding Proteins; Skin Diseases; Structure-Activity Relationship; Tretinoin; Vitamin A; Vitamin A Deficiency

In this article, we survey recent advances in basic as well as clinical studies on retinoids including structure-function correlation of retinoids, effects of retinoids on cell growth, anticancer activities, immunological potentiation, initiation and promotion of cancer, differentiation, and chemoprevention.

Topics: Animals; Antibody Formation; Cell Differentiation; Cell Division; Diterpenes; Female; Humans; Male; Mice; Neoplasms; Retinaldehyde; Retinyl Esters; Vitamin A

Human cancer risks are inversely correlated with (a) blood retinol and (b) dietary beta-carotene. Although retinol in the blood might well be truly protective, this would be of little immediate value without discovery of the important external determinants of blood retinol which (in developed countries) do not include dietary retinol or beta-carotene. If dietary beta-carotene is truly protective--which could be tested by controlled trials--there are a number of theoretical mechanisms whereby it might act, some of which do not directly involve its 'provitamin A' activity.

Topics: Africa, Eastern; Asia; Carotenoids; Diet; Europe; Forecasting; Humans; Neoplasms; Retinaldehyde; Surveys and Questionnaires; United Kingdom; United States; Vitamin A

In this study, pH-sensitive loaded retinal/indocyanine green (ICG) micelles were developed to realize novel approaches for cellular senescence-photothermal synergistic therapy to treat cancer. The micelles could enable effective multi-modal imaging in vivo guided therapy and show anticancer activity in vitro and in vivo with satisfactory biosafety.

Topics: Cellular Senescence; Humans; Hydrogen-Ion Concentration; Indocyanine Green; Micelles; Multimodal Imaging; Neoplasms; Phototherapy; Retinaldehyde; Theranostic Nanomedicine

Carotenoids are widely used as important micronutrients in food. Furthermore, carotenoid supplementation has been used in the treatment of diseases associated with oxidative stress. However, in some clinical studies harmful effects have been observed, for example, a higher incidence of lung cancer in individuals exposed to extraordinary oxidative stress. The causal mechanisms are still unclear. Carotenoid cleavage products (CCPs), including highly reactive aldehydes and epoxides, are formed during oxidative attacks in the course of antioxidative action. Here, we tested the hypothesis that CCPs may increase oxidative stress by impairing mitochondrial function. We found that CCPs strongly inhibit state 3 respiration of isolated rat liver mitochondria even at concentrations between 0.5 and 20 microM. This was true for retinal, beta-ionone, and mixtures of cleavage products, which were generated in the presence of hypochlorite to mimic their formation in inflammatory regions. The inhibition of mitochondrial respiration was accompanied by a reduction in protein sulfhydryl content, decreasing glutathione levels and redox state, and elevated accumulation of malondialdehyde. Changes in mitochondrial membrane potential favor functional deterioration of the adenine nucleotide translocator. The findings may reflect a basic mechanism of increasing the risk of cancer induced by CCPs.

Topics: Animals; beta Carotene; Carcinogens; Cell Respiration; Dose-Response Relationship, Drug; Glutathione; Kinetics; Malondialdehyde; Mitochondria; Models, Biological; Neoplasms; Norisoprenoids; Oxidative Phosphorylation; Oxidative Stress; Rats; Retinaldehyde; Risk Factors; Terpenes

Topics: Chemical Phenomena; Chemistry; Humans; Isotretinoin; Neoplasms; Precancerous Conditions; Retinaldehyde; Skin Diseases; Tretinoin; Vitamin A; Vitamin A Deficiency

Treatment of all-trans-retinal with a series of 1,3-diketones using Knoevenagel conditions gave the expected condensation products. These retinylidene 1,3-diketones were characterized and their biological activities in the hamster tracheal organ culture test measured. It was found that the cyclohexane- 1,3-dione derivatives are highly active in this in vitro assay, while other 1,3-diketones are less active. Retinylidenedimedone has been chosen for further evaluation.

Topics: Animals; Cell Differentiation; Cricetinae; Epithelial Cells; Epithelium; Ketones; Neoplasms; Organ Culture Techniques; Retinaldehyde; Trachea; Vitamin A