Telomestatin is a macrocyclic chemical compound

Chemical compound

A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...

 that acts by inhibiting the telomerase

Telomerase

Telomerase is an enzyme that adds DNA sequence repeats to the 3' end of DNA strands in the telomere regions, which are found at the ends of eukaryotic chromosomes. This region of repeated nucleotide called telomeres contains non-coding DNA material and prevents constant loss of important DNA from...

 activity of the cancer cells. It was first isolated from the bacteria Streptomyces anulatus. Telomestatin induces the formation of basket-type G-quadruplex

G-quadruplex

In molecular biology, G-quadruplexes are nucleic acid sequences that are rich in guanine and are capable of forming a four-stranded structure...

 (G4) structures from hybrid-type G-quadruplexes in the telomeric region

Telomere

A telomere is a region of repetitive DNA sequences at the end of a chromosome, which protects the end of the chromosome from deterioration or from fusion with neighboring chromosomes. Its name is derived from the Greek nouns telos "end" and merοs "part"...

. Upon formation of G4 structure there will be a decrease in the activity of the telomerase, which is involved in the replication of the telomeres and as a result the cell dies due to Hayflick

Hayflick limit

The Hayflick limit is the number of times a normal cell population will divide before it stops, presumably because the telomeres reach a critical length....

 type senescence

Senescence

Senescence or biological aging is the change in the biology of an organism as it ages after its maturity. Such changes range from those affecting its cells and their function to those affecting the whole organism...

.