Antiestrogen

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Antiestrogen
Drug class
Fulvestrant.svg
Fulvestrant, a steroidal antiestrogen and a drug used in the treatment of breast cancer.
Class identifiers
SynonymsEstrogen antagonists; Estrogen blockers; Estradiol antagonists
UseBreast cancer; Infertility; Male hypogonadism; Gynecomastia; transgender men
ATC codeL02BA
Biological targetEstrogen receptor
Chemical classSteroidal; Nonsteroidal (triphenylethylene, others)
External links
MeSHD020847
In Wikidata

Antiestrogens, also known as estrogen antagonists or estrogen blockers, are a class of drugs which prevent estrogens like estradiol from mediating their biological effects in the body. They act by blocking the estrogen receptor (ER) and/or inhibiting or suppressing estrogen production.[1][2] Antiestrogens are one of three types of sex hormone antagonists, the others being antiandrogens and antiprogestogens.[3]Antiestrogens are commonly used to stop steroid hormones, estrogen, from binding to the estrogen receptors leading to the decrease of estrogen levels.[4] Decreased levels of estrogen can lead to complications in sexual development.[5] Antiandrogens are sex hormone antagonists which are able to lower the production and the effects that testosterone can have on female bodies.[6]

Types and examples[edit]

Antiestrogens include selective estrogen receptor modulators (SERMs) like tamoxifen, clomifene, and raloxifene, the ER silent antagonist and selective estrogen receptor degrader (SERD) fulvestrant,[7][8] aromatase inhibitors (AIs) like anastrozole, and antigonadotropins including androgens/anabolic steroids, progestogens, and GnRH analogues.

Estrogen receptors (ER) like ERα and ERβ include activation function 1 (AF1) domain and activation function 2 (AF2) domain in which SERMS act as antagonists for the AF2 domain, while “pure” antiestrogens like ICI 182,780 and ICI 164,384 are antagonists for the AF1 and AF2 domains.[9]

Although aromatase inhibitors and antigonadotropins can be considered antiestrogens by some definitions, they are often treated as distinct classes.[10] Aromatase inhibitors and antigonadotropins reduce the production of estrogen, while the term "antiestrogen" is often reserved for agents reducing the response to estrogen.[11]

Medical uses[edit]

Antiestrogens are used for:

Side effects[edit]

Side effects of antiestrogens include hot flashes, osteoporosis, breast atrophy, vaginal dryness, and vaginal atrophy. In addition, they may cause depression and reduced libido.

Pharmacology[edit]

Antiestrogens act as antagonists of the estrogen receptors, ERα and ERβ.

Affinities of estrogen receptor ligands for the ERα and ERβ
Ligand Other names Relative binding affinities (RBA, %)a Absolute binding affinities (Ki, nM)a Action
ERα ERβ ERα ERβ
Estradiol E2; 17β-Estradiol 100 100 0.115 (0.04–0.24) 0.15 (0.10–2.08) Estrogen
Estrone E1; 17-Ketoestradiol 16.39 (0.7–60) 6.5 (1.36–52) 0.445 (0.3–1.01) 1.75 (0.35–9.24) Estrogen
Estriol E3; 16α-OH-17β-E2 12.65 (4.03–56) 26 (14.0–44.6) 0.45 (0.35–1.4) 0.7 (0.63–0.7) Estrogen
Estetrol E4; 15α,16α-Di-OH-17β-E2 4.0 3.0 4.9 19 Estrogen
Alfatradiol 17α-Estradiol 20.5 (7–80.1) 8.195 (2–42) 0.2–0.52 0.43–1.2 Metabolite
16-Epiestriol 16β-Hydroxy-17β-estradiol 7.795 (4.94–63) 50 ? ? Metabolite
17-Epiestriol 16α-Hydroxy-17α-estradiol 55.45 (29–103) 79–80 ? ? Metabolite
16,17-Epiestriol 16β-Hydroxy-17α-estradiol 1.0 13 ? ? Metabolite
2-Hydroxyestradiol 2-OH-E2 22 (7–81) 11–35 2.5 1.3 Metabolite
2-Methoxyestradiol 2-MeO-E2 0.0027–2.0 1.0 ? ? Metabolite
4-Hydroxyestradiol 4-OH-E2 13 (8–70) 7–56 1.0 1.9 Metabolite
4-Methoxyestradiol 4-MeO-E2 2.0 1.0 ? ? Metabolite
2-Hydroxyestrone 2-OH-E1 2.0–4.0 0.2–0.4 ? ? Metabolite
2-Methoxyestrone 2-MeO-E1 <0.001–<1 <1 ? ? Metabolite
4-Hydroxyestrone 4-OH-E1 1.0–2.0 1.0 ? ? Metabolite
4-Methoxyestrone 4-MeO-E1 <1 <1 ? ? Metabolite
16α-Hydroxyestrone 16α-OH-E1; 17-Ketoestriol 2.0–6.5 35 ? ? Metabolite
2-Hydroxyestriol 2-OH-E3 2.0 1.0 ? ? Metabolite
4-Methoxyestriol 4-MeO-E3 1.0 1.0 ? ? Metabolite
Estradiol sulfate E2S; Estradiol 3-sulfate <1 <1 ? ? Metabolite
Estradiol disulfate Estradiol 3,17β-disulfate 0.0004 ? ? ? Metabolite
Estradiol 3-glucuronide E2-3G 0.0079 ? ? ? Metabolite
Estradiol 17β-glucuronide E2-17G 0.0015 ? ? ? Metabolite
Estradiol 3-gluc. 17β-sulfate E2-3G-17S 0.0001 ? ? ? Metabolite
Estrone sulfate E1S; Estrone 3-sulfate <1 <1 >10 >10 Metabolite
Estradiol benzoate EB; Estradiol 3-benzoate 10 ? ? ? Estrogen
Estradiol 17β-benzoate E2-17B 11.3 32.6 ? ? Estrogen
Estrone methyl ether Estrone 3-methyl ether 0.145 ? ? ? Estrogen
ent-Estradiol 1-Estradiol 1.31–12.34 9.44–80.07 ? ? Estrogen
Equilin 7-Dehydroestrone 13 (4.0–28.9) 13.0–49 0.79 0.36 Estrogen
Equilenin 6,8-Didehydroestrone 2.0–15 7.0–20 0.64 0.62 Estrogen
17β-Dihydroequilin 7-Dehydro-17β-estradiol 7.9–113 7.9–108 0.09 0.17 Estrogen
17α-Dihydroequilin 7-Dehydro-17α-estradiol 18.6 (18–41) 14–32 0.24 0.57 Estrogen
17β-Dihydroequilenin 6,8-Didehydro-17β-estradiol 35–68 90–100 0.15 0.20 Estrogen
17α-Dihydroequilenin 6,8-Didehydro-17α-estradiol 20 49 0.50 0.37 Estrogen
Δ8-Estradiol 8,9-Dehydro-17β-estradiol 68 72 0.15 0.25 Estrogen
Δ8-Estrone 8,9-Dehydroestrone 19 32 0.52 0.57 Estrogen
Ethinylestradiol EE; 17α-Ethynyl-17β-E2 120.9 (68.8–480) 44.4 (2.0–144) 0.02–0.05 0.29–0.81 Estrogen
Mestranol EE 3-methyl ether ? 2.5 ? ? Estrogen
Moxestrol RU-2858; 11β-Methoxy-EE 35–43 5–20 0.5 2.6 Estrogen
Methylestradiol 17α-Methyl-17β-estradiol 70 44 ? ? Estrogen
Diethylstilbestrol DES; Stilbestrol 129.5 (89.1–468) 219.63 (61.2–295) 0.04 0.05 Estrogen
Hexestrol Dihydrodiethylstilbestrol 153.6 (31–302) 60–234 0.06 0.06 Estrogen
Dienestrol Dehydrostilbestrol 37 (20.4–223) 56–404 0.05 0.03 Estrogen
Benzestrol (B2) 114 ? ? ? Estrogen
Chlorotrianisene TACE 1.74 ? 15.30 ? Estrogen
Triphenylethylene TPE 0.074 ? ? ? Estrogen
Triphenylbromoethylene TPBE 2.69 ? ? ? Estrogen
Tamoxifen ICI-46,474 3 (0.1–47) 3.33 (0.28–6) 3.4–9.69 2.5 SERM
Afimoxifene 4-Hydroxytamoxifen; 4-OHT 100.1 (1.7–257) 10 (0.98–339) 2.3 (0.1–3.61) 0.04–4.8 SERM
Toremifene 4-Chlorotamoxifen; 4-CT ? ? 7.14–20.3 15.4 SERM
Clomifene MRL-41 25 (19.2–37.2) 12 0.9 1.2 SERM
Cyclofenil F-6066; Sexovid 151–152 243 ? ? SERM
Nafoxidine U-11,000A 30.9–44 16 0.3 0.8 SERM
Raloxifene 41.2 (7.8–69) 5.34 (0.54–16) 0.188–0.52 20.2 SERM
Arzoxifene LY-353,381 ? ? 0.179 ? SERM
Lasofoxifene CP-336,156 10.2–166 19.0 0.229 ? SERM
Ormeloxifene Centchroman ? ? 0.313 ? SERM
Levormeloxifene 6720-CDRI; NNC-460,020 1.55 1.88 ? ? SERM
Ospemifene Deaminohydroxytoremifene 0.82–2.63 0.59–1.22 ? ? SERM
Bazedoxifene ? ? 0.053 ? SERM
Etacstil GW-5638 4.30 11.5 ? ? SERM
ICI-164,384 63.5 (3.70–97.7) 166 0.2 0.08 Antiestrogen
Fulvestrant ICI-182,780 43.5 (9.4–325) 21.65 (2.05–40.5) 0.42 1.3 Antiestrogen
Propylpyrazoletriol PPT 49 (10.0–89.1) 0.12 0.40 92.8 ERα agonist
16α-LE2 16α-Lactone-17β-estradiol 14.6–57 0.089 0.27 131 ERα agonist
16α-Iodo-E2 16α-Iodo-17β-estradiol 30.2 2.30 ? ? ERα agonist
Methylpiperidinopyrazole MPP 11 0.05 ? ? ERα antagonist
Diarylpropionitrile DPN 0.12–0.25 6.6–18 32.4 1.7 ERβ agonist
8β-VE2 8β-Vinyl-17β-estradiol 0.35 22.0–83 12.9 0.50 ERβ agonist
Prinaberel ERB-041; WAY-202,041 0.27 67–72 ? ? ERβ agonist
ERB-196 WAY-202,196 ? 180 ? ? ERβ agonist
Erteberel SERBA-1; LY-500,307 ? ? 2.68 0.19 ERβ agonist
SERBA-2 ? ? 14.5 1.54 ERβ agonist
Coumestrol 9.225 (0.0117–94) 64.125 (0.41–185) 0.14–80.0 0.07–27.0 Xenoestrogen
Genistein 0.445 (0.0012–16) 33.42 (0.86–87) 2.6–126 0.3–12.8 Xenoestrogen
Equol 0.2–0.287 0.85 (0.10–2.85) ? ? Xenoestrogen
Daidzein 0.07 (0.0018–9.3) 0.7865 (0.04–17.1) 2.0 85.3 Xenoestrogen
Biochanin A 0.04 (0.022–0.15) 0.6225 (0.010–1.2) 174 8.9 Xenoestrogen
Kaempferol 0.07 (0.029–0.10) 2.2 (0.002–3.00) ? ? Xenoestrogen
Naringenin 0.0054 (<0.001–0.01) 0.15 (0.11–0.33) ? ? Xenoestrogen
8-Prenylnaringenin 8-PN 4.4 ? ? ? Xenoestrogen
Quercetin <0.001–0.01 0.002–0.040 ? ? Xenoestrogen
Ipriflavone <0.01 <0.01 ? ? Xenoestrogen
Miroestrol 0.39 ? ? ? Xenoestrogen
Deoxymiroestrol 2.0 ? ? ? Xenoestrogen
β-Sitosterol <0.001–0.0875 <0.001–0.016 ? ? Xenoestrogen
Resveratrol <0.001–0.0032 ? ? ? Xenoestrogen
α-Zearalenol 48 (13–52.5) ? ? ? Xenoestrogen
β-Zearalenol 0.6 (0.032–13) ? ? ? Xenoestrogen
Zeranol α-Zearalanol 48–111 ? ? ? Xenoestrogen
Taleranol β-Zearalanol 16 (13–17.8) 14 0.8 0.9 Xenoestrogen
Zearalenone ZEN 7.68 (2.04–28) 9.45 (2.43–31.5) ? ? Xenoestrogen
Zearalanone ZAN 0.51 ? ? ? Xenoestrogen
Bisphenol A BPA 0.0315 (0.008–1.0) 0.135 (0.002–4.23) 195 35 Xenoestrogen
Endosulfan EDS <0.001–<0.01 <0.01 ? ? Xenoestrogen
Kepone Chlordecone 0.0069–0.2 ? ? ? Xenoestrogen
o,p'-DDT 0.0073–0.4 ? ? ? Xenoestrogen
p,p'-DDT 0.03 ? ? ? Xenoestrogen
Methoxychlor p,p'-Dimethoxy-DDT 0.01 (<0.001–0.02) 0.01–0.13 ? ? Xenoestrogen
HPTE Hydroxychlor; p,p'-OH-DDT 1.2–1.7 ? ? ? Xenoestrogen
Testosterone T; 4-Androstenolone <0.0001–<0.01 <0.002–0.040 >5000 >5000 Androgen
Dihydrotestosterone DHT; 5α-Androstanolone 0.01 (<0.001–0.05) 0.0059–0.17 221–>5000 73–1688 Androgen
Nandrolone 19-Nortestosterone; 19-NT 0.01 0.23 765 53 Androgen
Dehydroepiandrosterone DHEA; Prasterone 0.038 (<0.001–0.04) 0.019–0.07 245–1053 163–515 Androgen
5-Androstenediol A5; Androstenediol 6 17 3.6 0.9 Androgen
4-Androstenediol 0.5 0.6 23 19 Androgen
4-Androstenedione A4; Androstenedione <0.01 <0.01 >10000 >10000 Androgen
3α-Androstanediol 3α-Adiol 0.07 0.3 260 48 Androgen
3β-Androstanediol 3β-Adiol 3 7 6 2 Androgen
Androstanedione 5α-Androstanedione <0.01 <0.01 >10000 >10000 Androgen
Etiocholanedione 5β-Androstanedione <0.01 <0.01 >10000 >10000 Androgen
Methyltestosterone 17α-Methyltestosterone <0.0001 ? ? ? Androgen
Ethinyl-3α-androstanediol 17α-Ethynyl-3α-adiol 4.0 <0.07 ? ? Estrogen
Ethinyl-3β-androstanediol 17α-Ethynyl-3β-adiol 50 5.6 ? ? Estrogen
Progesterone P4; 4-Pregnenedione <0.001–0.6 <0.001–0.010 ? ? Progestogen
Norethisterone NET; 17α-Ethynyl-19-NT 0.085 (0.0015–<0.1) 0.1 (0.01–0.3) 152 1084 Progestogen
Norethynodrel 5(10)-Norethisterone 0.5 (0.3–0.7) <0.1–0.22 14 53 Progestogen
Tibolone 7α-Methylnorethynodrel 0.5 (0.45–2.0) 0.2–0.076 ? ? Progestogen
Δ4-Tibolone 7α-Methylnorethisterone 0.069–<0.1 0.027–<0.1 ? ? Progestogen
3α-Hydroxytibolone 2.5 (1.06–5.0) 0.6–0.8 ? ? Progestogen
3β-Hydroxytibolone 1.6 (0.75–1.9) 0.070–0.1 ? ? Progestogen
Footnotes: a = (1) Binding affinity values are of the format "median (range)" (# (#–#)), "range" (#–#), or "value" (#) depending on the values available. The full sets of values within the ranges can be found in the Wiki code. (2) Binding affinities were determined via displacement studies in a variety of in-vitro systems with labeled estradiol and human ERα and ERβ proteins (except the ERβ values from Kuiper et al. (1997), which are rat ERβ). Sources: See template page.

History[edit]

The first nonsteroidal antiestrogen was discovered by Lerner and coworkers in 1958.[12] Ethamoxytriphetol (MER-25) was the first antagonist of the ER to be discovered,[13] followed by clomifene and tamoxifen.[14][15]

See also[edit]

References[edit]

  1. ^ "Definition of antiestrogen - NCI Dictionary of Cancer Terms, Definition of antiestrogen - NCI Dictionary of Cancer Terms".,
  2. ^ "antiestrogen" at Dorland's Medical Dictionary
  3. ^ Nath JL (2006). Using Medical Terminology: A Practical Approach. Lippincott Williams & Wilkins. pp. 977–. ISBN 978-0-7817-4868-1.
  4. ^ McKeage K, Curran MP, Plosker GL (2004-03-01). "Fulvestrant: a review of its use in hormone receptor-positive metastatic breast cancer in postmenopausal women with disease progression following antiestrogen therapy". Drugs. 64 (6): 633–48. doi:10.2165/00003495-200464060-00009. PMID 15018596.
  5. ^ Amenyogbe E, Chen G, Wang Z, Lu X, Lin M, Lin AY (2020-02-07). "A Review on Sex Steroid Hormone Estrogen Receptors in Mammals and Fish". International Journal of Endocrinology. 2020: 5386193. doi:10.1155/2020/5386193. PMC 7029290. PMID 32089683.
  6. ^ Angus LM, Nolan BJ, Zajac JD, Cheung AS (September 2020). "A systematic review of antiandrogens and feminization in transgender women". Clinical Endocrinology. n/a (n/a). doi:10.1111/cen.14329. PMID 32926454.
  7. ^ Ottow E, Weinmann H (8 September 2008). Nuclear Receptors as Drug Targets. John Wiley & Sons. pp. 164–165. ISBN 978-3-527-62330-3.
  8. ^ Chabner BA, Longo DL (8 November 2010). Cancer Chemotherapy and Biotherapy: Principles and Practice. Lippincott Williams & Wilkins. pp. 660–. ISBN 978-1-60547-431-1.
  9. ^ Pike, Ashley C.W.; Brzozowski, A.Marek; Walton, Julia; Hubbard, Roderick E.; Thorsell, Ann-Gerd; Li, Yi-Lin; Gustafsson, Jan-Åke; Carlquist, Mats (2001-02-01). "Structural Insights into the Mode of Action of a Pure Antiestrogen". Structure. 9 (2): 145–153. doi:10.1016/S0969-2126(01)00568-8. ISSN 0969-2126.
  10. ^ Riggins RB, Bouton AH, Liu MC, Clarke R (2005). "Antiestrogens, aromatase inhibitors, and apoptosis in breast cancer". Vitamins and Hormones. Vitamins & Hormones. 71: 201–37. doi:10.1016/S0083-6729(05)71007-4. ISBN 9780127098715. PMID 16112269.
  11. ^ Thiantanawat A, Long BJ, Brodie AM (November 2003). "Signaling pathways of apoptosis activated by aromatase inhibitors and antiestrogens". Cancer Research. 63 (22): 8037–50. PMID 14633737.
  12. ^ MacGregor JI, Jordan VC (June 1998). "Basic guide to the mechanisms of antiestrogen action". Pharmacological Reviews. 50 (2): 151–96. PMID 9647865.
  13. ^ Maximov PY, McDaniel RE, Jordan VC (23 July 2013). Tamoxifen: Pioneering Medicine in Breast Cancer. Springer Science & Business Media. pp. 7–. ISBN 978-3-0348-0664-0.
  14. ^ Jordan VC (27 May 2013). Estrogen Action, Selective Estrogen Receptor Modulators and Women's Health: Progress and Promise. World Scientific. pp. 7, 112. ISBN 978-1-84816-959-3.
  15. ^ Sneader W (23 June 2005). Drug Discovery: A History. John Wiley & Sons. pp. 198–199. ISBN 978-0-471-89979-2.

External links[edit]

 This article incorporates public domain material from the U.S. National Cancer Institute document: "Dictionary of Cancer Terms".