| Abstract | Mnogo je članaka objavljeno o ulozi antioksidansa, pravilnom načinu ishrane i prilagodbi života u svrhu spriječavanja pojave raka.No, potencijalna uloga tih faktora na utjecaj raka kod ljudi je većinom bila zapostavljena. Opsežna in vitro te ograničena in vivo istraživanja su otkrila da individualni antioksidansi kao što je vitamin A (retinoidi), vitamin E ( primarno α-tokoferil sukcinat), vitamin C (primarno natrijev askorbat) i karotenoidi (primarno polarni karotenoidi) induciraju diferencijaciju i inhibiciju rasta stanica, različitim mehanizmima, i u različitim postotcima u stanica raka kod ljudi i glodavaca. Predloženi mehanizmi za te efekte uključuju inhibiciju aktivnosti protein kinaze C, prostgladin E1 stimuliranu adenilat ciklaznu aktivnost, ekspresiju c-myc, H-ras, i transkripcijskog faktora (E2F) te indukciju transformirajućeg faktora rasta-b i p21 gena. Nadalje, vitamini sa antioksidativnom aktivnošću individualno ili u kombinaciji, pospješuju efekt inhibicije rasta uzrokovanog x-zračenjem, kemoterapijskim lijekovima, hipertermijom, i modifikatorom biološkog odgovora na tumorske stanice, primarno u in vitro uvjetima. Ovi vitamini, korišteni individualno, također reduciraju toksičnost koju prouzrokuju standardni tumorski terapijski lijekovi na normalne stanice. Prehrana s niskim udjelom masti i visokim udjelom vlakna može povećati efikasnost standardnih kemoterapijskih lijekova; pretpostavljeni mehanizam djelovanja uključuje povećanu razinu butanske kiseline i vezanje potencijalnih mutagena u gastrointestalnom traktu na vlakna te smanjenje razine rasta promovirajućih agenata kao što su prostagladini, određene masne kiseline i estrogen. Zbog toga je predložena hipoteza u kojoj nadomjestak s mješavinom vitamina s antioksidanskim svojstvima zajedno sa načinom prehrane i promjenom stila života mogu poboljšati efikasnost standardne i eksperimentalne kemoterapije. |
| Abstract (english) | Numerous articles and several reviews have been published on the role of antioxidants, and diet and lifestyle modifications in cancer prevention. However, the potential role of these factors in the management of human cancer have been largely ignored. Extensive in vitro studies and limited in vivo studies have revealed that individual antioxidants such as vitamin A (retinoids), vitamin E (primarily a-tocopheryl succinate), vitamin C (primarily sodium ascorbate) and carotenoids (primarily polar carotenoids) induce cell differentiation and growth inhibition to various degrees in rodent and human cancer cells by complex mechanisms. The proposed mechanisms for these effects include inhibition of protein kinase C activity, prostaglandin E1-stimulated adenylate cyclase activity, expression of c-myc, H-ras, and a transcription factor (E2F), and induction of transforming growth factor-b and p21 genes. Furthermore, antioxidant vitamins individually or in combination enhance the growth-inhibitory effects of x-irradiation, chemotherapeutic agents, hyperthermia, and biological response modifiers on tumor cells, primarily in vitro. These vitamins, individually, also reduce the toxicity of several standard tumor therapeutic agents on normal cells. Low fat and high fiber diets can further enhance the efficacy of standard cancer therapeutic agents; the proposed mechanisms for these effects include the production of increased levels of butyric acid and binding of potential mutagens in the gastrointestinal tract by high fiber and reduced levels of growth promoting agents such as prostaglandins, certain fatty acids and estrogen.Therefore is proposed a working hypothesis that multiple antioxidant vitamin supplements together with diet and lifestyle modifications may improve the efficacy of standard and experimental cancer therapies. |
