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S Saez

Publications and source records attributed to S Saez.

83 records · Page 5Linked to original sources
PubMedDate not supplied

Specific receptors for 1,25-dihydroxyvitamin D3 (1,25-DR) and human colorectal carcinogenesis.

Because it is a common prerequisite for steroid responsiveness in target tissue, we investigated the presence of specific 1,25-DR in spontaneous human colorectal adenocarcinomas (ADC) and adjacent normal-appearing mucosa (NAM) from 23 operative specimens (12 male and 11 female patients). 1,25-DR was determined in cytosol by a DCC assay technique. 1,25-DR was present in 21 of 23 NAM and in only 4 of 23 HCRA. All positive ADC were well differentiated. Receptor content expressed in femtomoles/mg of protein (mean +/- SEM) was respectively 63.9 +/- 7.6 for right colon NAM and 51.3 +/- 12.9 for left colon or rectum NAM. When we compared all NAM specimens, receptor content was 56.7 +/- 8.0 femtomoles/mg of protein. No difference in 1,25-DR NAM level was observed between right colon and left colon or rectum. In adenocarcinoma the mean content was 66.5 +/- 14 fmoles/mg of protein. Scatchard analysis showed a single class of specific high-affinity saturable 1,25-DR with a dissociation constant (Kd) of 0.97 +/- 0.57 and 1.03 +/- 0.39 chi 10(-10) M in NAM and ADC respectively. These preliminary data represent the first demonstration of 1,25-DR throughout the entire human colon and indicate that the receptivity for this hormone is often lost during malignant transformation of the human colorectal mucosa. In addition, 1,25-DR could be a marker of differentiation in ADC. These preliminary results provide evidence supporting the addition of Vitamin D to the roster of developmental cancer chemopreventative agents.

Adenocarcinoma↗
PubMedDate not supplied

The role of vitamin D3 in the proliferation of a human colon cancer cell line in vitro.

LoVo, a cultured colon cancer cell line, is shown to possess a receptor for 1,25-dihydroxy vitamin D3 (1 alpha,25(OH)2D3) with a low capacity (28 fmol/mg protein) and high affinity (Kd: 1.9 x 10(-21)0M). When these cells were grown in monolayer culture in a chemically defined serum-free medium, a significant inhibition of proliferation was seen in the presence of 10 nM to 1 microM of 1 alpha,25(OH)2D3 (p less than 0.005. Furthermore, 1 alpha,25(OH)2D3 delayed early attachment of cells. After 8 days of treatment, aggregated cuboidal cells showed a marked change to an apparently spindle like morphology. The 1 alpha,25(OH)2D3 growth-inhibitory effect was modulated by verapamil (1 microM), a calcium channel blocker, hydrocortisone (1 microM), and moxestrol (1 mM), an estrogen analogue, and 2% charcoal-treated fetal bovine serum. This study represents the first demonstration of 1 alpha,25(OH)2D3 modulation of growth of human colon cells.

Calcitriol↗
PubMedDate not supplied

Flow cytometry analysis of the growth inhibitory effect of 4-hydroxy-tamoxifen on a human breast carcinoma cell line.

Growth kinetics of BT-20 cells (an ER- cell line) have been studied with flow cytometry, cell counting and 3H-thymidine incorporation. The cell cycle lasts about 40 hours, with a maximum SG2M about 25h after seeding. 4-Hydroxy-tamoxifen (OH-Tamoxifen) (10(-7) M to 10(-5) M) inhibits BT-20 cell growth with maximum inhibition at 24-28h after plating. The inhibitory effect of OH-Tamoxifen is also demonstrated by a decrease in 3H-thymidine incorporation and by a reduction in cell number. These results suggest that OH-Tamoxifen is able to act upon an ER-cell line through a pathway which is different from that of estrogens.

Breast Neoplasms↗
PubMedDate not supplied

[Sex-steroid receptors in malignant tumours (author's transl)].

The most frequently studied tumour in a target organ for steroid activity has been breast cancer in women. The hormone-dependent nature of these tumours is now accepted as being related to the presence of oestradiol and progesterone. The fact that these receptors are found in mammary tumours might be connected with one aspect of cell differentiation which bears a close relationship to slower clinical progression. Hormonal manipulations are now employed routinely to treat other tumours of these target organs: endometrium, prostate, kidneys. Receptors of this type have been demonstrated in other solid tumours (melanoma) but hormonal treatment has given disappointing results. Tumours in organs that are not typical targets for these hormones do contain steroid receptors, but their significance in relation to cancer induction and growth phenomena has not been elucidated.

Breast Neoplasms↗
PubMedDate not supplied

Effect of physiological concentrations of sex hormones on the formation of "early" sheep red blood cell rosettes by human lymphocytes. Possible relations with the presence of sex-hormone-cytosol-receptors in lymphocytes.

The formation of "early" sheep red blood cell rosettes by normal human peripheral blood lymphocytes was increased by incubation with physiological concentration of 17 beta-Estradiol. This effect was shown to be hormone specific. Whole cell incorporation of radioactive hormones and analysis by gel filtration of cytosols incubated with labeled hormones have shown a saturable fixation of estrogens and androgens. These results raise the possibility that normal human peripheral blood lymphocytes are target cells for sex steroid hormones.

Animals↗
PubMedDate not supplied

Effects of an androgenic derivative on the development of chemically-induced mammary carcinogenesis in the rat.

The effects of an androgenic derivative--danazol--on the development of dimethylbenz(a)anthracene (DMBA)-rat mammary carcinogenesis were studied. Animals in the treated group received danazol (10-12 mg/kg/day) during 169 days, starting 5 days after DMBA induction. As compared with tumours in control animals, those treated with danazol appear later and are significantly smaller. Moreover, this treatment reduced the incidence of animals affected by mammary cancer and the average number of malignant tumours in each animal. In the same way, the incidence of animals with missing nodules was significantly higher in the group treated with danazol. It is concluded that danazol has an inhibitory effect on experimental mammary tumours. This effect seems to be greater the earlier the treatment is started and the longer time it is applied.

9,10-Dimethyl-1,2-benzanthracene↗