Nadine Devleeschouwer

Hydroxy derivatives of tamoxifen

In the exploration of the structural features that affect the RBA (binding affinity for the estrogen receptor of rat uterus relative to that of estradiol) in the tamoxifen [trans-(Z)-1-[4-[2-(dimethylamino)ethoxy]phenyl ]-1,2-diphenyl-1-butene] series, several derivatives variously substituted in the 1-phenyl group have been synthesized. [In the tamoxifen series, the descriptors E and Z, which define the configuration of the geometrical isomers and depend on the location and nature of substituents in the aromatic moieties and the ethyl group, may vary, although the relative configuration (cis or trans) does not. In order to avoid confusion the terms cis and trans will be used in this paper to refer to the relative positions of the 4-[2-(dimethylamino)ethoxy]phenyl and ethyl (or hydroxyethyl, hydroxypropyl, or bromo) substituents attached to the ethene moiety.] The final stage of each synthesis involved acid-catalyzed dehydration of a tertiary alcohol, and, in contrast to the known 3- and 4-hydroxy derivatives which were obtained as near-equimolar cis,trans mixtures, only the trans forms of the 2-hydroxy, 2-methyl, 2,4-dihydroxy, and 4-hydroxy-2-methyl derivatives were obtained. Also, in contrast to the trans forms of the 3- and 4-hydroxy derivatives, which are readily equilibrated to cis,trans mixtures, the trans 2-hydroxy derivative could not be isomerized. Tamoxifen and 2-methyltamoxifen had similar RBAs (approximately 1% of that of E2), but that of 2-hydroxytamoxifen was much lower (0.1%). Introduction of a second hydroxyl group (2,4-dihydroxy derivative) enhanced the RBA, and for the 4-hydroxy-2-methyl derivative, the RBA and growth inhibitory activity against the MCF-7 mammary tumor cell line in vitro were high and comparable to those of 4-hydroxytamoxifen, a metabolite of the parent drug. Tamoxifen derivatives hydroxylated at positions 3 or 4 of the 1-butene moiety and the 5-hydroxy-1-pentene analogue were also synthesized, but they had very low RBA values.

Estrogen-induced protein in the human breast cancer cell line MCF7

Summary Present data show that a cytosolic protein, similar in charge and molecular weight to the uterine IP, is constitutively synthesized in two mammary tumor cell lines containing (MCF-7) or lacking (Evsa-T) the estrogen receptor (ER). Estrogen treatment stimulates amino-acid incorporation in this protein in the estrogen responsive line MCF-7, only. Further work is needed before concluding about the identity of this 46000 dalton protein and the uterine IP.

Estrogen-induced synthesis and secretion of proteins in the human breast cancer cell line MCF-7.

Abstract The estrogen-induced tumor protein previously described by us in the receptor-positive MCF-7 cells was resolved here by two-step fractionation into four proteins of 46, 5Z 54 and 60,000 Mr. These proteins differ from the uterine IP (48,000 Mr) by being slightly more acidic and by lacking creatine kinase activity. Furthermore, they are not stimulated in Evsa-T cells lacking the estrogen receptors. In MCF-7 cells estrogenic stimulation also provokes a broad spectrum of changes in the secreted proteins. Some proteins (of 37, 46, 54 and 60,000 Mr) are synthetised and secreted at higher than basal rate. A preexisting protein of low turn-over rate (50,000 Mr) is secreted at higher rate after E 2 treatment. In view of these observations, it seems obvious that the examination of a sole protein as a criterion of hormone-dependence should be misleading.

Absence of antitumor activity of ORG 5895, a 11?-aziridinylmethyl derivative of estradiol, on the MXT mammary tumor and the P388 leukemia

The presence of estrogen receptors in human breast cancers led to the concept of using estrogen-linked cytotoxic agents for the treatment of the disease. An 11 fl-(1-aziridinylmethyl) derivative of estradiol has recently been synthesized (ORG 5895; formula in Fig. 1) [5]. This compound displays a significant binding affinity for the estrogen receptor (+ 5% of estradiol) [4, 5]. Moreover, its estrone analog slightly modulates the in vitro growth of the MCF-7 breast cancer cell line (stimulation at 10 .7 and 10 .8 M; inhibition at 10 .6 M) [4]. These observations led us to investigate the potential antitumor activity of the compound on the in vivo growth of the hormone-dependent MXT mouse mammary tumor [2, 6]. Six-week-old MXT mammary tumors were minced in minimum essential medium. Pieces of + 15 mm 3 were inoculated into 60 BDF1 female mice (8-10weeks old). Animals were randomized and distributed into four groups of 15 mice each (3 treated and 1 control groups). The treated groups received ORG 5895 SC twice a week at 0.5, 5, and 50 mg/kg, respectively (suspension in physiological saline + Tween 80); the control group received the vehicle only. Administration started at the time of transplantation and was continued for 10 weeks. Tumor size, expressed as the product of two perpendicular diameters, was measured every 2 weeks. Animals were weighed at the time of measurement. Examination of the animals revealed that ORG 5895 did not delay the appearance of palpable tumor nodules. After 4weeks of treatment tumors were found in all animals, indicating that the compound did not reduce the tumor take. With regard to the tumor size, ORG 5895 also appeared totally devoid of antitumor activity. Figure I shows that its sole effect was a stimulation of tumor growth, which was only significant at 50 mg/kg after 8 and 10 weeks of treatment (P < 0.002 and 0.005, respectively; Mann-Whitney U-test). This effect was associated with a shortening of the survival of the animals (animals still living after 10 weeks: controls, 15; 0.5 mg/kg, 13; 5 mg/kg, 14; 50 mg/kg, 10). No loss of body weight was recorded. Notably, a control experiment run in parallel allowed verification of the expected hormone-dependent properties of the tumor transplants used [2, 6]. Thus ovariectomy produced a significant reduction of tumor growth; administration of estradiol and medroxyprogesterone acetate abolished this effect. At the end of the experiment, the uterus and vagina were taken at random from three animals of each group. A marked