Masato Tanabe

Last updated
Masato Tanabe
NationalityAmerican
Alma mater UC Berkeley
Known forContributions to drug discovery
AwardsSRI Fellow (1984)
JPMA Distinguished Service Award (2001)
SRI Hall of Fame (2004)
Scientific career
Institutions SRI International
Doctoral advisor William G. Dauben

Masato "Mas" Tanabe was a drug researcher at SRI International, where he spent 45 years studying steroid hormones, which are instrumental in combatting breast cancer and prostate cancer. [1] [2]

Contents

Education

Tanabe graduated from the University of San Francisco in 1947 with a degree in chemistry; his thesis was "Studies in the hydroaromatic series". [3] Tanabe would go on to study under professor William G. Dauben at the University of California, Berkeley. [4]

Career

Tanabe was program manager of Steroid Chemistry group, then director of SRI's Bio-Organic Chemistry Laboratory for much of his career, and later the director of SRI's Pharmaceutical Chemistry group. [1] In 1967, he was on a team that discovered Eschenmoser-Tanabe fragmentation. [5] Much of the work was sponsored by the National Institute of Health and Schering Plough, the latter of which has at least eight patents and 30 journal articles via work sponsored at SRI. [2] Other notable accomplishments include the use of stable isotopes to study metabolism. He inserted Carbon-13 into antibiotics to demonstrate how microbes can assemble antibiotics to defend themselves, then used magnetic resonance spectroscopy to determine how the antibiotic was formed. [2]

His work resulted in the development of the steroid SR16234, which has been used to treat breast cancer. [1] [6] A compound discovered in a previous contract from NIH showed potential - it acted like "anti-estrogen" in the breasts and uterus but like normal estrogen elsewhere in the body, and were thus more "tissue-selective". [2] A contract was proposed to Taiho Pharmaceutical in July 1996, and within six years and slightly under $3 million (an unusually short amount of time) two new drugs were discovered and tested on people (particularly people for which tamoxifen has failed): SR16234 and SR16287. [2] The first of those, SR16234, also inhibited the growth of blood vessels (angiogenesis) and accelerated the death of cancer cells (apoptosis) and thus was particularly well suited to be an anti-cancer drug. [2] As of August 2010, the drug had been through five Phase I and two Phase II studies, [7] [8] and Phase III studies are being planned. [9]

Legacy

Tanabe was named an SRI Fellow in 1984 for his contributions to steroid hormone therapeutics, and to SRI's Alumni Hall of Fame in 2004. [1]

Tanabe worked with many SRI post-doctoral and international fellows; in addition, 45 Japanese scientists studied under him at SRI in Menlo Park, California under SRI's academic exchange program. As a result, he was awarded the Japanese Pharmaceutical Society's Distinguished Service Award on March 27, 2001. [1] [2] He is the first person outside Japan to receive that award. [1] [2]

Related Research Articles

Estrone Chemical compound

Estrone (E1), also spelled oestrone, is a steroid, a weak estrogen, and a minor female sex hormone. It is one of three major endogenous estrogens, the others being estradiol and estriol. Estrone, as well as the other estrogens, are synthesized from cholesterol and secreted mainly from the gonads, though they can also be formed from adrenal androgens in adipose tissue. Relative to estradiol, both estrone and estriol have far weaker activity as estrogens. Estrone can be converted into estradiol, and serves mainly as a precursor or metabolic intermediate of estradiol. It is both a precursor and metabolite of estradiol.

Aromatase inhibitor

Aromatase inhibitors (AIs) are a class of drugs used in the treatment of breast cancer in postmenopausal women and in men, and gynecomastia in men. They may also be used off-label to reduce estrogen conversion when supplementing testosterone exogenously. They may also be used for chemoprevention in women at high risk for breast cancer.

Exemestane Breast cancer medication

Exemestane, sold under the brand name Aromasin among others, is a medication used to treat breast cancer. It is a member of the class of antiestrogens known as aromatase inhibitors. Some breast cancers require estrogen to grow. Those cancers have estrogen receptors (ERs), and are called ER-positive. They may also be called estrogen-responsive, hormonally-responsive, or hormone-receptor-positive. Aromatase is an enzyme that synthesizes estrogen. Aromatase inhibitors block the synthesis of estrogen. This lowers the estrogen level, and slows the growth of cancers.

Polyestradiol phosphate Chemical compound

Polyestradiol phosphate (PEP), sold under the brand name Estradurin, is an estrogen medication which is used primarily in the treatment of prostate cancer in men. It is also used in women to treat breast cancer, as a component of hormone therapy to treat low estrogen levels and menopausal symptoms, and as a component of feminizing hormone therapy for transgender women. It is given by injection into muscle once every four weeks.

Tibolone

Tibolone, sold under the brand name Livial among others, is a medication which is used in menopausal hormone therapy and in the treatment of postmenopausal osteoporosis and endometriosis. The medication is available alone and is not formulated or used in combination with other medications. It is taken by mouth.

Lasofoxifene

Lasofoxifene, sold under the brand name Fablyn, is a nonsteroidal selective estrogen receptor modulator (SERM) which is marketed by Pfizer in Lithuania and Portugal for the prevention and treatment of osteoporosis and for the treatment of vaginal atrophy, and the result of an exclusive research collaboration with Ligand Pharmaceuticals (LGND). It also appears to have had a statistically significant effect of reducing breast cancer in women according to a study published in The Journal of the National Cancer Institute.

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. Antiestrogens are one of three types of sex hormone antagonists, the others being antiandrogens and antiprogestogens.Antiestrogens are commonly used to stop steroid hormones, estrogen, from binding to the estrogen receptors leading to the decrease of estrogen levels. Decreased levels of estrogen can lead to complications in sexual development. Antiandrogens are sex hormone antagonists which are able to lower the production and the effects that testosterone can have on female bodies.

Hormone replacement therapy (HRT), also known as menopausal hormone therapy or postmenopausal hormone therapy, is a form of hormone therapy used to treat symptoms associated with female menopause. These symptoms can include hot flashes, vaginal atrophy, accelerated skin aging, vaginal dryness, decreased muscle mass, sexual dysfunction, and bone loss. They are in large part related to the diminished levels of sex hormones that occur during menopause.

Taiho Pharmaceutical Co., Ltd. is a Japanese pharmaceutical company, subsidiary of Otsuka Holdings. The company focuses on developing cancer treatments. Taiho is headquartered in Tokyo, Japan. Taiho is an R&D-driven specialty pharma focusing on the three fields of oncology, allergies and immunology, and urology.

Estradiol dipropionate

Estradiol dipropionate (EDP), sold under the brand names Agofollin, Di-Ovocylin, and Progynon DP among others, is an estrogen medication which has been used in hormone therapy for menopausal symptoms and low estrogen levels in women and in the treatment of gynecological disorders. It has also been used in feminizing hormone therapy for transgender women and in the treatment of prostate cancer in men. Although widely used in the past, estradiol dipropionate has largely been discontinued and is mostly no longer available today. It appears to remain in use only in Japan, Macedonia, and Australia. Estradiol dipropionate is given by injection into muscle at intervals ranging from once or twice a week to once every week and a half to two weeks.

TAS-108

TAS-108, also known as SR-16234, is a drug discovered by Masato Tanabe and under development by SRI International and Taiho Pharmaceutical. It is a steroid hormone that has shown signs of treating and preventing breast cancer, even in patients where tamoxifen has failed.

Paroxypropione

Paroxypropione, also known as paraoxypropiophenone, is a synthetic nonsteroidal estrogen which has been used medically as an antigonadotropin in Spain and Italy but appears to no longer be marketed. It was first synthesized in 1902. The antigonadotropic properties of the drug were discovered in 1951 and it entered clinical use shortly thereafter.

Endoxifen Chemical compound

Endoxifen, also known as 4-hydroxy-N-desmethyltamoxifen, is a potent protein kinase C (PKC) inhibitor. It is a chemical that is under development for estrogen receptor-positive breast cancer cells.

Estradiol (medication) steroidal hormone medication

Estradiol (E2) is a medication and naturally occurring steroid hormone. It is an estrogen and is used mainly in menopausal hormone therapy and to treat low sex hormone levels in women. It is also used in hormonal birth control for women, in hormone therapy for transgender women, and in the treatment of hormone-sensitive cancers like prostate cancer in men and breast cancer in women, among other uses. Estradiol can be taken by mouth, held and dissolved under the tongue, as a gel or patch that is applied to the skin, in through the vagina, by injection into muscle or fat, or through the use of an implant that is placed into fat, among other routes.

Irosustat

Irosustat is an orally active, irreversible, nonsteroidal inhibitor of steroid sulfatase (STS) and member of the aryl sulfamate ester class of drugs that was under development by Sterix Ltd and Ipsen for the treatment of hormone-sensitive cancers such as breast cancer, prostate cancer, and endometrial cancer but has not yet been marketed. The drug was first designed and synthesized in the group of Professor Barry V L Potter at the Department of Pharmacy & Pharmacology, University of Bath, working together with Professor Michael J. Reed at Imperial College, London and its initial development was undertaken through the university spin-out company Sterix Ltd and overseen by Cancer Research UK (CRUK). Results of the "first-in-class" clinical trial in breast cancer of an STS inhibitor in humans were published in 2006 and dose optimisation studies and further clinical data have been reported.

Androstanolone

Androstanolone, or stanolone, also known as dihydrotestosterone (DHT) and sold under the brand name Andractim among others, is an androgen and anabolic steroid (AAS) medication and hormone which is used mainly in the treatment of low testosterone levels in men. It is also used to treat breast development and small penis in males. It is typically given as a gel for application to the skin, but can also be used as an ester by injection into muscle.

Estrogen (medication)

An estrogen (E) is a type of medication which is used most commonly in hormonal birth control and menopausal hormone therapy, and as part of feminizing hormone therapy for transgender women. They can also be used in the treatment of hormone-sensitive cancers like breast cancer and prostate cancer and for various other indications. Estrogens are used alone or in combination with progestogens. They are available in a wide variety of formulations and for use by many different routes of administration. Examples of estrogens include bioidentical estradiol, natural conjugated estrogens, synthetic steroidal estrogens like ethinylestradiol, and synthetic nonsteroidal estrogens like diethylstilbestrol. Estrogens are one of three types of sex hormone agonists, the others being androgens/anabolic steroids like testosterone and progestogens like progesterone.

A sex-hormonal agent, also known as a sex-hormone receptor modulator, is a type of hormonal agent which specifically modulates the effects of sex hormones and of their biological targets, the sex hormone receptors. The sex hormones include androgens such as testosterone, estrogens such as estradiol, and progestogens such as progesterone. Sex-hormonal agents may be either steroidal or nonsteroidal in chemical structure and may serve to either enhance, inhibit, or have mixed effects on the function of the sex hormone systems.

Barry V. L. Potter

Barry Victor Lloyd Potter MAE FMedSci is Professor of Medicinal & Biological Chemistry at the University of Oxford, Wellcome Trust Senior Investigator and a Fellow of University College, Oxford.

Non steroidal aromatase inhibitors

Non-Steroidal Aromatase Inhibitors (NSAIs) are one of two categories of aromatase inhibitors (AIs). AIs are divided into two categories, steroidal aromatase inhibitors and non-steroidal aromatase inhibitors that is based on their mechanism of action and structure. NSAIs are mainly used to treat breast cancer in women. NSAIs binding is a reversible process where NSAIs binds to the aromatase enzyme through non-covalent interactions. When aromatase inhibitors (AIs) are used to treat breast cancer the main target is the aromatase enzyme which is responsible for the high estrogen level.

References

  1. 1 2 3 4 5 6 "Alumni Hall of Fame 2004: Masato Tanabe". SRI International . Retrieved 2013-02-10.
  2. 1 2 3 4 5 6 7 8 Nielson, Donald (2006). A Heritage of Innovation: SRI's First Half Century. Menlo Park, California: SRI International. pp. 10–. ISBN   978-0-9745208-1-0.
  3. Register, Volume 2. University of California, Berkeley. 1952.
  4. Nozoe, Tetsuo (1991-05-05). Seventy Years in Organic Chemistry. American Chemical Society. p. 144. ISBN   0841217696.
  5. Masato Tanabe, David F. Crowe and Robert L. Dehn (1967). "A novel fragmentation reaction of α,β-epoxyketones the synthesis of acetylenic ketones". Tetrahedron Letters . 8 (40): 3943–3946. doi:10.1016/S0040-4039(01)89757-4.
  6. "Novel Anti-Angiogenic Agents for Breast Cancer Therapy". California Breast Cancer Research Program. Archived from the original on 2013-04-11. Retrieved 2013-02-10.
  7. "SRI International to Advance Clinical Development of TAS-108, a Late-Stage Breast Cancer Drug" (Press release). SRI International . Retrieved 2013-02-24.
  8. "TAS-108: A Better Anti-Estrogen Drug for Treating Breast Cancer". SRI International. Archived from the original on 2013-03-04. Retrieved 2013-02-24.
  9. Buzdar, Aman U. (2005-01-15). "TAS-108: A Novel Steroidal Antiestrogen". Clinical Cancer Research . American Association for Cancer Research. 11 (2): 902–906. PMID   15701885 . Retrieved 2013-02-24.