DOTA-TATE, DOTATATE or DOTA-octreotate is a substance which, when bound to various radionuclide

Radionuclide

A radionuclide is an atom with an unstable nucleus, which is a nucleus characterized by excess energy available to be imparted either to a newly created radiation particle within the nucleus or to an atomic electron. The radionuclide, in this process, undergoes radioactive decay, and emits gamma...

s, has been tested for the treatment and diagnosis of certain types of cancer, mainly neuroendocrine tumours.

Chemistry and mechanism of action

DOTA-TATE is an amide of the acid DOTA (top left in the image), which acts as a chelator for a radionuclide, and (Tyr

Tyrosine

Tyrosine or 4-hydroxyphenylalanine, is one of the 22 amino acids that are used by cells to synthesize proteins. Its codons are UAC and UAU. It is a non-essential amino acid with a polar side group...

³)-octreotate

Octreotate

Octreotate or octreotide acid is a somatostatin analogue that is closely related to octreotide. Its amino acid sequence isH-D-Phe-Cys-Phe-D-Trp-Lys-Thr-Cys-Thr-OHwhile octreotide has the terminal threonine reduced to the corresponding amino alcohol....

, a derivative of octreotide

Octreotide

Octreotide is an octapeptide that mimics natural somatostatin pharmacologically, though it is a more potent inhibitor of growth hormone, glucagon, and insulin than the natural hormone...

. The latter binds to somatostatin receptor

Somatostatin receptor

There are five known somatostatin receptors:* SST1 * SST2 * SST3 * SST4 * SST5 All are G protein-coupled seven transmembrane receptors.-External links:...

s, which are found on the cell surfaces of a number of neuroendocrine tumours, and thus directs the radioactivity into the tumour.

Usage examples

Gallium

Gallium

Gallium is a chemical element that has the symbol Ga and atomic number 31. Elemental gallium does not occur in nature, but as the gallium salt in trace amounts in bauxite and zinc ores. A soft silvery metallic poor metal, elemental gallium is a brittle solid at low temperatures. As it liquefies...

 (⁶⁸Ga) DOTA-TATE (GaTate) is used for tumour diagnosis in positron emission tomography

Positron emission tomography

Positron emission tomography is nuclear medicine imaging technique that produces a three-dimensional image or picture of functional processes in the body. The system detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide , which is introduced into the body on a...

 (PET). DOTA-TATE PET/CT has a much higher sensitivity compared to In-111 octreotide imaging.

Lutetium (¹⁷⁷Lu) DOTA-TATE has been tested for the treatment of tumors such as carcinoid

Carcinoid

Carcinoid is a slow-growing type of neuroendocrine tumor, originating in the cells of the neuroendocrine system.In 2000, the World Health Organization redefined "carcinoid", but this new definition has not been accepted by all practitioners. This has led to some complexity in distinguishing...

 and endocrine pancreatic tumor. It is presently unavailable in North America. Select medical centers in Europe offer this treatment, for instance Uppsala Centre of Excellence in Neuroendocrine Tumors and Erasmus University

Erasmus University

Erasmus University Rotterdam is a university in the Netherlands, located in Rotterdam. The university is named after Desiderius Erasmus Roterodamus, a 15th century humanist and theologian...

. In Australia, treatment is available at the Peter MacCallum Cancer Centre.