Octpep-1 is a peptide derived from the octopus kaurna, or the southern sand octopus, a species native to the seas around the Great Australian Bight and Tasmania. Octpep-1 disrupts PI3K/AKT/mTOR pathway signalling and selectively reduces the proliferative capacity of human melanoma BRAFV600E mutated cells, with minimal effects on fibroblasts. Octpep-1 has weak agonist activity at tachykinin NK1 receptors but its antiproliferative activity is independent of NK1R expression. Octpep-1 acts synergistically in combination with the mTORC1 inhibitor rapamycin or the ERK1/2 inhibitor LY3214996 to enhance its antiproliferative effects and augment cytotoxicity. Octpep-1 reduces the progression of tumours in vivo, being effective in xenograft mouse melanoma and zebrafish models.
