Estradiol and tamoxifen differently affects the inhibitory effects of vitamin A and their metabolites on the proliferation and expression of alpha2beta1 integrins in MCF-7 breast cancer cells.

PURPOSE: Retinoids are well known inhibitors of estrogen-dependent breast cancer cell growth and differentiation. alpha2beta1 integrins are involved in the normal growth and differentiation of breast cells, they also take part in many pathological processes including malignancies. The aim of the study was to evaluate the effect of estradiol and tamoxifen on the inhibitory action of retinoids on the proliferation of MCF-7 breast cancer cells and alpha2beta1 integrin expression. MATERIALS AND METHODS: Evaluation was based on [3H]thymidine incorporation and the proliferative activity of PCNA- and Ki 67-positive cells. Expression of alpha2beta1 was assessed through immunocytochemical analysis. RESULTS: Treatment of cancer cells with the examined compounds and tamoxifen (10 microM) revealed that only 13-cis retinoic acid (13-cis RA) and all-trans retinoic acid (ATRA) (10(-5) M) decreased cells proliferation compared to the tamoxifen group (30.84%+/-3.32, p<0.01 and 31.05%+/-4.67, p<0.01, respectively). The lowest fraction of PCNA positive cells was also observed after the simultaneous addition ATRA (10(-5) M) and tamoxifen (10 microM) (30.75%+/-0.95, p<0.01, compared to the tamoxifen group). Our results showed that the decrease of alpha2beta1 integrin expression by 13-cis RA (10(-5) M, 49.6+/-3.25%) and ATRA (10-9 M, 15.0%+/-5.0) was augmented by tamoxifen and to a lesser extent by estradiol, particularly in the case of ATRA at 10(-7) or 10(-9) M. CONCLUSIONS: This data suggest that tamoxifen augments the inhibitory effect of retinoids on proliferation and alpha2beta1 integrin expression in MCF-7 cells.

Does variability in carotenoid composition and concentration in tissues of the breast and reproductive tract in women depend on type of lesion?

PURPOSE: Vitamin A takes part in many physiological and pathological processes in women's reproductive organs. The study objective was to compare the carotenoid content in benign and malignant lesions of the breast, ovary and uterus, and to demonstrate quantitative and qualitative similarities or differences between the study groups. MATERIALS AND METHODS: Materials for analysis were physiological and pathological tissues of breast, ovary and uterus. The carotenoid pigments were isolated using column chromatography (CC), thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). RESULTS: Sixteen carotenoids were identified in the study material, including those belonging to the provitamin A group. The most common were: beta-carotene, beta-cryptoxanthin, lutein, mutatoxanthin, violaxanthin, lutein epoxide and zeaxanthin. All the tissues subjected to analysis contained beta-carotene, 98% of the tissues had beta-cryptoxanthin, whereas alpha-carotene was detected in about 50% of breast tissue. No differences in carotenoid concentration were found between benign and malignant lesions in the examined tissues, apart from hydroxyechinenone, canthaxanthin, astaxanthin, lutein epoxide, antheraxanthin and neoxanthin. Similarly, no differences in concentration of the provitamin A carotenoids (alpha-carotene, beta-carotene, beta-cryptoxanthin, and echinenone) were found between benign and malignant lesions except hydroxyechinenone. The highest total content of carotenoids and the biggest spectrum of predominant carotenoids were found in the breast. Only in tissues of malignant lesions of the uterus, we observed statistically higher total content of carotenoids compared to remaining samples from the uterus (p<0.001) and more frequent isolation of some carotenoids (compared to benign lesions). CONCLUSION: The results of our study confirmed the presence of a high diversity of carotenoids in the physiologic, benign and malignant tissues of the breast and the reproductive tract in women. The differences observed among the frequency of isolation of some carotenoids do not allow to make straightforward conclusions. The frequent isolation of provitamin A carotenoids in the examined material and the lack of their occurrence as major carotenoids may be connected with using them in the cellular biological processes. However, this requires further investigation.

Preliminary identification of carotenoids in malignant and benign neoplasms of the breast and surrounding fatty tissue.

An attempt has been made to identify the carotenoids present in the tissue of neoplastic tumors and the surrounding fatty tissue taken from women with histologically diagnosed cancer (ca ductale infiltrans, G2,G3; n=20) and those with benign changes (fibroadenoma, n=20). Carotenoid pigments were isolated using column and thin-layer chromatography. Prior to chromatography, the material was homogenized with acetone under nitrogen in dark glass bottles and the extracts kept in a refrigerator until analyzed. In the present study, we isolated 13 carotenoids belonging to provitamin A and nonprovitamin A carotenoids. The total content of carotenoids in microg/g of tissue was slightly lower in cancers and the surrounding fatty tissues in comparison to benign changes, but in general it was higher in the fatty tissue surrounding the tumors, irrespective of their histological structure (the mean values for cancers 20.433+/-10.64 vs fatty tissue 25.361+/-12.025, p<0.01; and the mean values for benign changes 22.889+/-12.011 vs fatty tissue 27.021+/-13.180, p<0.01). Epoxide carotenoids - lutein epoxide and violaxanthin, were predominant in fatty tissue, both in malignant and benign changes; epoxide carotenoids - mutatoxanthin and lutein epoxide and other carotenoids such as zeaxanthin, canthaxanthin, lutein and neoxanthin were predominant in neoplastic material. Beta carotene and lutein epoxide were found in all samples, alpha carotene was found in 50% of them. Antheraxanthin was present in fatty tissue only. Beta carotene, the main provitamin A carotenoid, content in the material examined ranged from 2.43 to 4.33% in tumor tissue and in fatty tissue surrounding the tumors it was twice as higs. Such carotenoids as 3'-lutein, canthaxanthin and astaxanthin were sporadic. No reoccurring carotenoid "sequences" were found despite the same histopathological diagnosis. No relationship was found between the neoplasm histopatological grade, lesion diameter and the occurrence of specific carotenoids.

13-cis retinoic acid and all-trans retinoic acid in the regulation of the proliferation and survival of human breast cancer cell line MCF-7.

Retinoids are a group of compounds which inhibit cell proliferation and induce cellular differentiation. The aim of this study was to compare the antiproliferative activity of various concentrations of 13-cis retinoic acid (isotretinoin) and all-trans retinoic acid (tretinoin) in a culture of the estrogen-sensitive human breast cancer cell line MCF-7. Evaluation was based on [3H]thymidine incorporation into the cancer cells and through immunocytochemical analysis of cell cycle-associated PCNA and Ki-67 protein expression. Both retinoids inhibited [3H]thymidine incorporation into the cancer cells most effectively at a concentration of 3x10(-3) M. Two basic substances used for line MCF-7 culture experiments, one stimulating - estradiol - and the other inhibiting - tamoxifen - were applied. Estradiol added to a culture containing decreasing concentrations of isotretinoin (from 3x10(-3) to 3x10(-8) M) caused a statistically significant reduction in the percentage of [3H]thymidine incorporation into the cancer cell line MCF-7, compared to the 17 beta estradiol group (189.25%+/-62.64, control=100%, p<0.05). In the group of decreasing tretinoin concentrations, statistically significant differences were found only at 3x10(-3), 3x10(-4) and 3x10(-8) M. Following culture supplementation with tamoxifen (1 microM), statistically significant differences were observed only at the highest concentrations of both retinoids (3x10(-3) and 3x10(-4) M). The evaluation of breast carcinoma cells with a positive immunocytochemical reaction to PCNA and Ki-67 has revealed that isotretinoin reduces their percentage in the most determined and statistically significant way (38.00%+/-2.58 and 39.25%+/-3.09), compared to the control group (86.50%+/-9.20 and 100%+/-3.87, p<0.001 and p<0.0001) and to the estradiol group (87.00%+/-6.79 and 86.10%+/-7.0, p<0.001). Apart from their blocking effect on the cell cycle, retinoids also induce the apoptotic pathway.

Carotenoid content in Anguilla anguilla (L.) individuals undertaking spawning migration.

The authors investigated the carotenoid content in different parts of Anguilla anguilla (L.) undertaking spawning migration, in spring, summer and autumn. By means of column and thin-layer chromatography, the following carotenoids were found to be present: beta-carotene, epsilon-carotene, beta-cryptoxanthin, neothxanthin, lutein, tunaxanthin, zeaxanthin, lutein epoxide, 3'-hydroxyechincnone, canthaxanthin, idoxanthin, phoenicoxanthin, alpha-doradexanthin, beta-doradexanthin and astaxanthin. In the eel examined individuals a different carotenoid content was found in October. In winter when eels do not feed and therefore do not absorb carotenoids, carotenoid content decreases in the liver, the intestines, and particularly in the muscles. In spring when eels undertake active life carotenoid concentration increases rapidly in these organs within a month. In summer during intensive predation, carotenoid concentration in the muscles reaches a maximum.

Adaptative role of carotenoids and carotenoproteins in Cyclops kolensis Lilljeborg (Crustacea: Copepoda) specimens to extremely eutrophical conditions.

The authors, using column, thin-layer, and ion-exchange chromatography, investigated carotenoid and carotenoprotein complex content in Cyclops kolensis specimens from an extremely eutrophic pond. The following carotenoids were found to be present: beta-carotene, beta-cryptoxanthin, lutein epoxide, crustaxanthin, 4'-hydroxyechinenone, canthaxanthin, and astaxanthin. Carotenoprotein complex containing astaxanthin as the prosthetic group name gamma-crustacyanine was purified from Cyclops kolensis individuals examined. The authors justify the adaptative role of these pigments in Cyclops kolensis specimens in extremely eutrophical conditions.

Carotenoid content in Lota lota (L.) individuals in various biological activity periods.

The authors investigated the carotenoid content in the particular parts of Lota lota in summer, autumn, and winter, i.e. when burbots exhibit the lowest and highest activity. By means of columnar and thin-layer chromatography, the following carotenoids were found to be present: alpha-carotene, beta-carotene, e-carotene, beta-cryptoxanthin, neothxanthin, lutein, 3'-epilutein, zeaxanthin, tunaxanthin, antheraxanthin, lutein epoxide, echinenone, 3'-hydroxyechinenone, idoxanthin, canthaxanthin, alpha-doradexanthin, beta-doradexanthin, astaxanthin, diatoxanthin, parasiloxanthin, monadoxanthin, 7,8-dihydroparasiloxanthin, mutatoxanthin and rhodoxanthin. In the Lota lota individuals examined, the content of carotenoids was found to differ in winter and summer. The total carotenoid content ranged from 0.067 (gonads of males) of to 6.095 micrograms g-1 wet weight (fins of males from December).