Streptozotocin or streptozocin ( INN, USP) (STZ) is a naturally occurring alkylating antineoplastic agent that is particularly toxic to the insulin-producing

beta cell Beta cells (β-cells) are specialized endocrine cells located within the pancreatic islets of Langerhans responsible for the production and release of insulin and amylin. Constituting ~50–70% of cells in human islets, beta cells play a vi ...

s of the

pancreas The pancreas (plural pancreases, or pancreata) is an Organ (anatomy), organ of the Digestion, digestive system and endocrine system of vertebrates. In humans, it is located in the abdominal cavity, abdomen behind the stomach and functions as a ...

in mammals. It is used in

medicine Medicine is the science and Praxis (process), practice of caring for patients, managing the Medical diagnosis, diagnosis, prognosis, Preventive medicine, prevention, therapy, treatment, Palliative care, palliation of their injury or disease, ...

for treating certain cancers of the islets of Langerhans and used in medical research to produce an

animal model An animal model (short for animal disease model) is a living, non-human, often genetic-engineered animal used during the research and investigation of human disease, for the purpose of better understanding the disease process without the risk of ha ...

for

hyperglycemia Hyperglycemia is a condition where unusually high amount of glucose is present in blood. It is defined as blood glucose level exceeding 6.9 mmol/L (125 mg/dL) after fasting for 8 hours or 10 mmol/L (180 mg/dL) 2 hours after eating. Blood gluc ...

and

Alzheimer's Alzheimer's disease (AD) is a neurodegenerative disease and the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in remembering recent events. As the disease advances, symptoms can include problems wit ...

in a large dose, as well as

type 2 diabetes Type 2 diabetes (T2D), formerly known as adult-onset diabetes, is a form of diabetes mellitus that is characterized by high blood sugar, insulin resistance, and relative lack of insulin. Common symptoms include increased thirst, frequent ...

type 1 diabetes Type 1 diabetes (T1D), formerly known as juvenile diabetes, is an autoimmune disease that occurs when the body's immune system destroys pancreatic cells (beta cells). In healthy persons, beta cells produce insulin. Insulin is a hormone require ...

with multiple low doses.

Usage

Streptozotocin is approved by the U.S.

Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respo ...

(FDA) for treating

metastatic Metastasis is a pathogenic agent's spreading from an initial or primary site to a different or secondary site within the host's body; the term is typically used when referring to metastasis by a cancerous tumor. The newly pathological sites, ...

cancer of the pancreatic islet cells. Since it carries a substantial risk of toxicity and rarely cures the cancer, its use is generally limited to patients whose cancer cannot be removed by surgery. In these patients, streptozotocin can reduce the tumor size and reduce symptoms (especially

hypoglycemia Hypoglycemia (American English), also spelled hypoglycaemia or hypoglycæmia (British English), sometimes called low blood sugar, is a fall in blood sugar to levels below normal, typically below 70 mg/dL (3.9 mmol/L). Whipple's tria ...

due to excessive

insulin Insulin (, from Latin ''insula'', 'island') is a peptide hormone produced by beta cells of the pancreatic islets encoded in humans by the insulin (''INS)'' gene. It is the main Anabolism, anabolic hormone of the body. It regulates the metabol ...

secretion by

insulinoma An insulinoma is a tumour of the pancreas that is derived from beta cells and secretes insulin. It is a rare form of a neuroendocrine tumour. Most insulinomas are benign in that they grow exclusively at their origin within the pancreas, but a m ...

s). A typical dose is 500 mg/m²/day by intravenous injection, for 5 days, repeated every 4–6 weeks. Due to its high toxicity to beta cells, in scientific research, streptozotocin has also been long used for inducing

insulitis Insulitis is an inflammation of the islets of Langerhans, a collection of endocrine tissue located in the pancreas that helps regulate glucose levels, and is classified by specific targeting of immune cell (T and B lymphocytes, macrophages and den ...

and diabetes on experimental animals. Streptozotocin has also been used for modeling Alzheimer's disease through memory loss in mice.

Mechanism

Streptozotocin is a

glucosamine Glucosamine (C6H13NO5) is an amino sugar and a prominent precursor in the biochemical synthesis of glycosylated proteins and lipids. Glucosamine is part of the structure of two polysaccharides, chitosan and chitin. Glucosamine is one of the mo ...

- nitrosourea compound. As with other

alkylating agents Alkylation is a chemical reaction that entails transfer of an alkyl group. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion, or a carbene (or their equivalents). Alkylating agents are reagents for effectin ...

in the nitrosourea class, it is toxic to cells by causing damage to the

DNA Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...

, though other mechanisms may also contribute. DNA damage induces activation of PARP which is likely more important for diabetes induction than the DNA damage itself. Streptozotocin is similar enough to glucose to be transported into the cell by the glucose transport protein

GLUT2 Glucose transporter 2 (GLUT2) also known as solute carrier family 2 (facilitated glucose transporter), member 2 (SLC2A2) is a transmembrane carrier protein that enables protein facilitated glucose movement across cell membranes. It is the princi ...

, but is not recognized by the other glucose transporters. This explains its relative toxicity to beta cells, since these cells have relatively high levels of GLUT2.

History

Streptozotocin was originally identified in the late 1950s as an

antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting pathogenic bacteria, bacterial infections, and antibiotic medications are widely used in the therapy ...

. The drug was discovered in a strain of the soil microbe '' Streptomyces achromogenes'' by scientists at the drug company Upjohn (now part of

Pfizer Pfizer Inc. ( ) is an American Multinational corporation, multinational Pharmaceutical industry, pharmaceutical and biotechnology corporation headquartered at The Spiral (New York City), The Spiral in Manhattan, New York City. Founded in 184 ...

) in

Kalamazoo, Michigan Kalamazoo ( ) is a city in Kalamazoo County, Michigan, United States, and its county seat. At the 2020 United States census, 2020 census, Kalamazoo had a population of 73,598. It is the principal city of the Kalamazoo–Portage metropolitan are ...

. The soil sample in which the microbe turned up had been taken from Blue Rapids, Kansas, which can therefore be considered the birthplace of streptozotocin. Upjohn filed for patent protection for the drug in August 1958 and was granted in March 1962. In the mid-1960s, streptozotocin was found to be selectively toxic to the beta cells of the pancreatic islets, the cells that normally regulate blood glucose levels by producing the

hormone A hormone (from the Ancient Greek, Greek participle , "setting in motion") is a class of cell signaling, signaling molecules in multicellular organisms that are sent to distant organs or tissues by complex biological processes to regulate physio ...

insulin. This suggested the drug's use as an animal model of diabetes, and as a medical treatment for cancers of the beta cells. In the 1960s and 1970s, the

National Cancer Institute The National Cancer Institute (NCI) coordinates the United States National Cancer Program and is part of the National Institutes of Health (NIH), which is one of eleven agencies that are part of the U.S. Department of Health and Human Services. ...

investigated streptozotocin's use in cancer

chemotherapy Chemotherapy (often abbreviated chemo, sometimes CTX and CTx) is the type of cancer treatment that uses one or more anti-cancer drugs (list of chemotherapeutic agents, chemotherapeutic agents or alkylating agents) in a standard chemotherapy re ...

. Upjohn filed for FDA approval of streptozotocin as a treatment for pancreatic islet cell cancer in November 1976, and approval was granted in July 1982. The drug was subsequently marketed as Zanosar. More recently, a growing body of studies has provided evidence that derangement of insulin signaling underlying type-2 diabetes significantly increase the risk of cognitive impairment and Alzheimer's disease (AD) progression. On this ground, the direct administration of STZ in the brain (i.e., by intracerebroventricular (ICV) infusion) has been used to develop an animal model of brain insulin resistance to mimic in rodents the pathophysiology of sporadic AD, which represents the most common form of AD in humans. STZ infusion in the brain induced accumulation of Amyloid beta (Aβ) protein, oxidative stress and cognitive impairment. Notably, there is now evidence that STZ infusion within the brain produced up-regulation of amyloid precursor protein (APP), tau hyperphosphorylation and neuroinflammation. Treatment with the cleavage-specific anti-tau 12A12 monoclonal antibody (mAb) can relieve APP upregulation, neuroinflammation and reduce cerebral oxidative stress, mitochondrial impairment, synaptic and histological alterations, as well as induce a nearly complete recovery of cognitive impairment in the STZ-induced SAD mouse model. Streptozotocin is now long off patent and many generic formulations are available.

Biosynthesis

Recent advancements in understanding the

biosynthesis Biosynthesis, i.e., chemical synthesis occurring in biological contexts, is a term most often referring to multi-step, enzyme-Catalysis, catalyzed processes where chemical substances absorbed as nutrients (or previously converted through biosynthe ...

of this

natural product A natural product is a natural compound or substance produced by a living organism—that is, found in nature. In the broadest sense, natural products include any substance produced by life. Natural products can also be prepared by chemical s ...

have been made by Balskus ''et al.'' In short, the authors found the

gene cluster A gene cluster is a group of two or more genes found within an organism's DNA that encode similar peptide, polypeptides or proteins which collectively share a generalized function and are often located within a few thousand base pairs of each othe ...

responsible for production of Streptozotocin in '' Streptomyces achromogenes'' and identified novel function of a non-heme iron enzyme, SznF, which forms the N-N bond in the N-nitrosourea pharmacophore by oxidative rearrangement.

References

External links