Which of the following is the mechanism of action for Hercep

Which of the following is the mechanism of action for Herceptin? Herceptin binds to the HER2 promoter to prevent transcription, thus lowering amounts of receptor. Herceptin binds to intracellular HER2 proteins to prevent cancer cells from dividing. Herceptin binds to HER3 and HER4 cell surface receptors to activate the immune system. Herceptin binds to extracellular domain of HER2 and prevents internalization and subsequent cancer cell division. Herceptin targets TNF alpha.

Solution

B) herceptin binds to intracellular ER2 proteins to prevent cancer cells from dividing

Trastuzumab (herceptin) activates p27 factor by inhibiting PI3K/Akt, Mirk and hKIS pathways. HER2 protein can be expressed up to 100 times more in cancer cells. PI3K/Akt, Mirk and hKIS are intracellular proteins in HER2 pathways are activated which promote cell proliferation. Signals present in these pathways promote growth of blood vessels in order to supplement for tumour formation or angiogenesis and therefore resulting in cell proliferation. Thus, when herceptin inhibits PI3K/Akt, Mirk and hKIS pathways, the cell proliferation is inhibited.