ER/Estrogen receptor; HSP90

Tamoxifen Citrate (ICI 46474) does not influence MDA-MB-231 cells, but it has a significant inhibitory effect on MCF-7 cells (EC50=1.41 μM) and a lessened inhibitory effect on T47D cells (EC50=2.5 μM)[2].

The ability to arbitrarily eliminate gene expression in adult animals in a tissue-specific way is one of the strategy's obvious advantages when using Tamoxifen Citrate-induced knockout. Tamoxifen citrate, 65 mg/kg per day, was intraperitoneally given into 7-week-old TmcsMed1-/- mice to investigate the function of Med1 in the adult heart. The mice were then euthanized at predetermined intervals. time after that. Three days after the Tamoxifen Citrate injection, Med1 expression started to decline (by about 70%), and five days later, Med1 expression in the heart was essentially nonexistent, according to qPCR analysis of RNA. Dilated cardiomyopathy is the result of heart-specific disruption of Med1 (TmcsMed1-/-) in adult mice caused by tamoxifen citrate [3].

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The Tamoxifen-inducible gene knockout strategy has clear advantages in that expression of a gene can be ablated in adult mice at will in a tissue specific manner. To study the role of Med1 in adult heart, 7-week old TmcsMed1-/- mice are given a daily Iintraperitoneal injection of Tamoxifen at a dose of 65 mg/kg for 5 days and killed at selected intervals thereafter. qPCR analysis of RNA shows that the Med1 expression begin to decrease after 3 days of Tamoxifen injection (about 70% decrease), and by 5 days of injection, Med1 expression is almost non-detectable in the heart. Tamoxifen-inducible cardiac-specific disruption of Med1 (TmcsMed1-/-) in adult mice causes dilated cardiomyopathy[3].

Background: Hsp90 is an essential molecular chaperone that is also a novel anti-cancer drug target. There is growing interest in developing new drugs that modulate Hsp90 activity.[4]
Methodology/principal findings: Using a virtual screening approach, 4-hydroxytamoxifen, the active metabolite of the anti-estrogen drug tamoxifen, was identified as a putative Hsp90 ligand. Surprisingly, while all drugs targeting Hsp90 inhibit the chaperone ATPase activity, it was found experimentally that 4-hydroxytamoxifen and tamoxifen enhance rather than inhibit Hsp90 ATPase.[4]
Conclusions/significance: Hence, tamoxifen and its metabolite are the first members of a new pharmacological class of Hsp90 activators.[4]

Previous studies have shown that a styrylpyrone derivative (SPD) from a local tropical plant had antiprogestin and antiestrogenic effects in early pregnant mice models (Azimahtol et al. 1991). Antiprogestins and antiestrogens can be exploited as a therapeutic approach to breast cancer treatment and thus the antitumor activity of SPD was tested in three different human breast cancer cell lines that is: MCF- 7, T47D and MDA-MB-231, employing, the antiproliferative assay of Lin and Hwang (1991) slightly modified. SPD (10(-10) - 10(-6) M) exhibited strong antiproliferative activity in estrogen and progestin-dependent MCF-7 cells (EC50 = 2.24 x 10(-7) M) and in hormone insensitive MDA-MB-231 (EC50 = 5.62 x 10(-7) M), but caused only partial inhibition of the estrogen- insensitive T47D cells (EC50 = 1.58 x 10(-6) M). However, tamoxifen showed strong inhibition of MCF-7 cells (EC50 = 1.41 x 10(-6) M) and to a lesser extent the T47D cells (EC50 = 2.5 x 10(-6) M) but did not affect the MDA-MB-231 cells. SPD at 1 microM exerted a beffer antiestrogenic activity than 1 microM tamoxifen in suppressing the growth of MCF-7 cells stimulated by 1 nM estradiol. Combined treatment of both SPD and tamoxifen at 1 microM showed additional inhibition on the growth of MCF-7 cells in culture. The antiproliferative properties of SPD are effective on both receptor positive and receptor negative mammary cancer cells, and thus appear to be neither dependent on cellular receptor status nor cellular hormone responses. This enhances in vivo approaches as tumors are heterogenous masses with varying receptor status[2].

[1]. Osborne CK. Tamoxifen in the treatment of breast cancer. N Engl J Med. 1998 Nov 26;339(22):1609-18.
[2]. Hawariah A, et al. In vitro response of human breast cancer cell lines to the growth-inhibitory effects of styrylpyrone derivative (SPD) and assessment of its antiestrogenicity. Anticancer Res. 1998 Nov-Dec;18(6A):4383-6.
[3]. Jia Y, et al. Cardiomyocyte-Specific Ablation of Med1 Subunit of the Mediator Complex Causes Lethal DilatedCardiomyopathy in Mice. PLoS One. 2016 Aug 22;11(8):e0160755.
[4]. Zhao R, et al. Tamoxifen enhances the Hsp90 molecular chaperone ATPase activity. PLoS One. 2010 Apr 1;5(4):e9934.
[5]. Laura Cooper, et al. Screening and Reverse-Engineering of Estrogen Receptor Ligands as Potent Pan-Filovirus Inhibitors. J Med Chem. 2020 Sep 4.
[6]. Feil S, et, al. Inducible Cre mice. Methods Mol Biol. 2009;530:343-63

Tamoxifen Citrate is the citrate salt of an antineoplastic nonsteroidal selective estrogen receptor modulator (SERM). Tamoxifen competitively inhibits the binding of estradiol to estrogen receptors, thereby preventing the receptor from binding to the estrogen-response element on DNA. The result is a reduction in DNA synthesis and cellular response to estrogen. In addition, tamoxifen up-regulates the production of transforming growth factor B (TGFb), a factor that inhibits tumor cell growth, and down-regulates insulin-like growth factor 1 (IGF-1), a factor that stimulates breast cancer cell growth. Tamoxifen also down-regulates protein kinase C (PKC) expression in a dose-dependant manner, inhibiting signal transduction and producing an antiproliferative effect in tumors such as malignant glioma and other cancers that overexpress PKC. NCI Thesaurus (NCIt)
Tamoxifen Citrate can cause developmental toxicity according to state or federal government labeling requirements. The CA Office of Environmental Health Hazard Assessment (OEHHA)
One of the SELECTIVE ESTROGEN RECEPTOR MODULATORS with tissue-specific activities. Tamoxifen acts as an anti-estrogen (inhibiting agent) in the mammary tissue, but as an estrogen (stimulating agent) in cholesterol metabolism, bone density, and cell proliferation in the ENDOMETRIUM.

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Antineoplastic Agents, Hormonal
Antineoplastic agents that are used to treat hormone-sensitive tumors. Hormone-sensitive tumors may be hormone-dependent, hormone-responsive, or both. A hormone-dependent tumor regresses on removal of the hormonal stimulus, by surgery or pharmacological block. Hormone-responsive tumors may regress when pharmacologic amounts of hormones are administered regardless of whether previous signs of hormone sensitivity were observed. The major hormone-responsive cancers include carcinomas of the breast, prostate, and endometrium; lymphomas; and certain leukemias. (From AMA Drug Evaluations Annual 1994, p2079)
Bone Density Conservation Agents
Agents that inhibit BONE RESORPTION and/or favor BONE MINERALIZATION and BONE REGENERATION. They are used to heal BONE FRACTURES and to treat METABOLIC BONE DISEASES such as OSTEOPOROSIS. Estrogen Antagonists
Compounds which inhibit or antagonize the action or biosynthesis of estrogenic compounds.
Selective Estrogen Receptor Modulators
A structurally diverse group of compounds distinguished from ESTROGENS by their ability to bind and activate ESTROGEN RECEPTORS but act as either an agonist or antagonist depending on the tissue type and hormonal milieu. They are classified as either first generation because they demonstrate estrogen agonist properties in the ENDOMETRIUM or second generation based on their patterns of tissue specificity. (Horm Res 1997;48:155-63)

C26H29NO.C6H8O7

563.64

563.25189

C, 68.19; H, 6.62; N, 2.49; O, 22.71

54965-24-1

Tamoxifen;10540-29-1;Tamoxifen-d5;157698-32-3

2733525

White to off-white solid powder

665.9ºC at 760 mmHg

140-144 °C

356.5ºC

4.75

144.6

O(C([H])([H])C([H])([H])N(C([H])([H])[H])C([H])([H])[H])C1C([H])=C([H])C(=C([H])C=1[H])/C(/C1C([H])=C([H])C([H])=C([H])C=1[H])=C(\C1C([H])=C([H])C([H])=C([H])C=1[H])/C([H])([H])C([H])([H])[H].O([H])C(C(=O)O[H])(C([H])([H])C(=O)O[H])C([H])([H])C(=O)O[H]

FQZYTYWMLGAPFJ-OQKDUQJOSA-N

InChI=1S/C26H29NO.C6H8O7/c1-4-25(21-11-7-5-8-12-21)26(22-13-9-6-10-14-22)23-15-17-24(18-16-23)28-20-19-27(2)3;7-3(8)1-6(13,5(11)12)2-4(9)10/h5-18H,4,19-20H2,1-3H3;13H,1-2H2,(H,7,8)(H,9,10)(H,11,12)/b26-25-;

2-[4-[(Z)-1,2-diphenylbut-1-enyl]phenoxy]-N,N-dimethylethanamine;2-hydroxypropane-1,2,3-tricarboxylic acid

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment, avoid exposure to moisture.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Solubility in Formulation 1: ≥ 2.08 mg/mL (3.69 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.08 mg/mL (3.69 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.08 mg/mL (3.69 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 4: 30% PEG400+0.5% Tween80+5% Propylene glycol : 30mg/mL

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Solubility in Formulation 5: 10 mg/mL (17.74 mM) in Corn Oil (add these co-solvents sequentially from left to right, and one by one), suspension solution; with ultrasonication.

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 (Please use freshly prepared in vivo formulations for optimal results.)