A report on Estrogen receptor and Antiestrogen

A dimer of the ligand-binding region of ERβ (PDB rendering based on ).
Fulvestrant, a steroidal antiestrogen and a drug used in the treatment of breast cancer.
The domain structures of ERα and ERβ, including some of the known phosphorylation sites involved in ligand-independent regulation.
A dimer of the ligand-binding region of ERα (PDB rendering based on ).
Nolvadex (tamoxifen) 20 mg
Arimidex (anastrozole) 1 mg

They act by blocking the estrogen receptor (ER) and/or inhibiting or suppressing estrogen production.

- Antiestrogen

Antiestrogens (e.g., fulvestrant, ICI-164384, ethamoxytriphetol)

- Estrogen receptor
A dimer of the ligand-binding region of ERβ (PDB rendering based on ).

9 related topics with Alpha

Overall
Tamoxifen, a nonsteroidal triphenylethylene antiestrogen and a widely used drug in the treatment of breast cancer.

Selective estrogen receptor modulator

6 links

Tamoxifen, a nonsteroidal triphenylethylene antiestrogen and a widely used drug in the treatment of breast cancer.
Figure 2: Nolvadex (tamoxifen) 20-milligram tablets (UK)
Figure 3: The domain structures of ERα and ERβ, including some of the known phosphorylation sites involved in ligand-independent regulation.
Figure 4: Structural basis for the mechanism of estrogen receptor agonist and antagonist action. The structures shown here are of the ligand binding domain (LBD) of the estrogen receptor (green cartoon diagram) complexed with either the agonist diethylstilbestrol (top, ) or antagonist 4-hydroxytamoxifen (bottom, ). The ligands are depicted as space filling spheres (white = carbon, red = oxygen). When an agonist is bound to a nuclear receptor, the C-terminal alpha helix of the LBD (H12; light blue) is positioned such that a coactivator protein (red) can bind to the surface of the LBD. Shown here is just a small part of the coactivator protein, the so-called NR box containing the LXXLL amino acid sequence motif. Antagonists occupy the same ligand binding cavity of the nuclear receptor. However antagonist ligands in addition have a sidechain extension which sterically displaces H12 to occupy roughly the same position in space as coactivators bind. Hence coactivator binding to the LBD is blocked.
Figure 5: 4-hydroxytamoxifen (red) overlaid with 17β-estradiol (black)
Figure 6: Trans-form of clomifene with the triphenylethylene structure in red.
Figure 8: Chemical structure of toremifene
Figure 9: Raloxifene has a benzothiophene group (red) and is connected with a flexible carbonyl hinge to a phenyl 4-piperidinoethoxy side chain (green).
Figure 10: Chemical structure of nafoxidine with the dihydronapthalene group in red.
Figure 11: Chemical structure of lasofoxifene shows cis-oriented phenyls.
Figure 12: Bazedoxifene includes an indole system (red) which is connected to an amine through a benzyloxyethyl chain (green).
Figure 13: Chemical structure of ospemifene. Ethoxy side chain ends with a hydroxy group (red) instead of a dimethylamino group as with first-generation SERMs.
Figure 14: The ABCD steroid ring system in 17β-estradiol.
Figure 15: "A ring" (A) and "D ring" (D) marked in raloxifene.

Selective estrogen receptor modulators (SERMs), also known as estrogen receptor agonist/antagonists (ERAAs), are a class of drugs that act on the estrogen receptor (ER).

Different tissues have different degrees of sensitivity to the activity of endogenous estrogens, so SERMs produce estrogenic or antiestrogenic effects depending on the specific tissue in question as well as the percentage of intrinsic activity (IA) of the SERM.

Nolvadex (tamoxifen) 20 mg tablets.

Tamoxifen

6 links

Selective estrogen receptor modulator used to prevent breast cancer in women and treat breast cancer in women and men.

Selective estrogen receptor modulator used to prevent breast cancer in women and treat breast cancer in women and men.

Nolvadex (tamoxifen) 20 mg tablets.
Crystallographic structure of afimoxifene (carbon = white, oxygen = red, nitrogen = blue) complexed with ligand binding domain of estrogen receptor alpha (ERα) (cyan ribbon).

Tamoxifen is used for the treatment of both early and advanced estrogen receptor-positive (ER-positive or ER+) breast cancer in pre- and postmenopausal women.

Tamoxifen interacts with certain other antiestrogens.

A bottle of raloxifene.

Raloxifene

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Medication used to prevent and treat osteoporosis in postmenopausal women and those on glucocorticoids.

Medication used to prevent and treat osteoporosis in postmenopausal women and those on glucocorticoids.

A bottle of raloxifene.

Raloxifene is a selective estrogen receptor modulator (SERM) and therefore a mixed agonist–antagonist of the estrogen receptor (ER).

It has estrogenic effects in bone and antiestrogenic effects in the breasts and uterus.

Estrogen receptor alpha

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Estrogen receptor alpha (ERα), also known as NR3A1 (nuclear receptor subfamily 3, group A, member 1), is one of two main types of estrogen receptor, a nuclear receptor that is activated by the sex hormone estrogen.

Antiestrogens (e.g., fulvestrant, ICI-164384, ethamoxytriphetol)

Clomifene

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Medication used to treat infertility in women who do not ovulate, including those with polycystic ovary syndrome.

Medication used to treat infertility in women who do not ovulate, including those with polycystic ovary syndrome.

It is a mixed agonist and antagonist of the estrogen receptor (ER).

Even though clomifene has some estrogenic effect, the antiestrogenic property is believed to be the primary source for stimulating ovulation.

Estrogen receptor beta

4 links

Estrogen receptor beta (ERβ) also known as NR3A2 (nuclear receptor subfamily 3, group A, member 2) is one of two main types of estrogen receptor—a nuclear receptor which is activated by the sex hormone estrogen.

Antiestrogens (e.g., fulvestrant, ICI-164384)

Ethamoxytriphetol

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Ethamoxytriphetol (developmental code name MER-25) is a synthetic nonsteroidal antiestrogen that was studied clinically in the late 1950s and early 1960s but was never marketed.

However, some estrogenic effects in the uterus have been observed, so it is not a pure antiestrogen (that is, a silent antagonist of the estrogen receptor (ER)) but is, instead, technically a selective estrogen receptor modulator (SERM).

Fulvestrant

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Medication used to treat hormone receptor -positive metastatic breast cancer in postmenopausal women with disease progression as well as HR-positive, HER2-negative advanced breast cancer in combination with palbociclib in women with disease progression after endocrine therapy.

Medication used to treat hormone receptor -positive metastatic breast cancer in postmenopausal women with disease progression as well as HR-positive, HER2-negative advanced breast cancer in combination with palbociclib in women with disease progression after endocrine therapy.

It works by binding to the estrogen receptor and destabilizing it, causing the cell's normal protein degradation processes to destroy it.

Fulvestrant is an antiestrogen which acts as an antagonist of the estrogen receptor (ER) and additionally as a selective estrogen receptor degrader (SERD).

Anastrozole

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Medication used in addition to other treatments for breast cancer.

Medication used in addition to other treatments for breast cancer.

It works by blocking the production of estrogens in the body, and hence has antiestrogenic effects.

The trial suggested that anastrozole is the preferred medical therapy for postmenopausal women with localized estrogen receptor-positive breast cancer.