Protein kinase B (PKB), also known as Akt, is the collective name of a set of three serine/threonine-specific protein kinases that play key roles in multiple cellular processes such as glucose metabolism, apoptosis, cell proliferation, transcription, and cell migration.
Targeted therapy or molecularly targeted therapy is one of the major modalities of medical treatment (pharmacotherapy) for cancer, others being hormonal therapy and cytotoxic chemotherapy. As a form of molecular medicine, targeted therapy blocks the growth of cancer cells by interfering with specific targeted molecules needed for carcinogenesis and tumor growth, rather than by simply interfering with all rapidly dividing cells. Because most agents for targeted therapy are biopharmaceuticals, the term biologic therapy is sometimes synonymous with targeted therapy when used in the context of cancer therapy. However, the modalities can be combined; antibody-drug conjugates combine biologic and cytotoxic mechanisms into one targeted therapy.
Axitinib, sold under the brand name Inlyta, is a small molecule tyrosine kinase inhibitor developed by Pfizer. It has been shown to significantly inhibit growth of breast cancer in animal (xenograft) models and has shown partial responses in clinical trials with renal cell carcinoma (RCC) and several other tumour types.
Panobinostat, sold under the brand name Farydak, is a medication used for the treatment of multiple myeloma. It is a hydroxamic acid and acts as a non-selective histone deacetylase inhibitor.
PARP inhibitors are a group of pharmacological inhibitors of the enzyme poly ADP ribose polymerase (PARP).
Iniparib was a drug candidate for cancer treatment. It was originally believed to act as an irreversible inhibitor of PARP1 and possibly other enzymes through covalent modification, but its effects against PARP were later disproven. It underwent clinical trials for treatment of some types of breast cancer, but was discontinued after disappointing phase III clinical trials.
Phosphoinositide 3-kinase inhibitors are a class of medical drugs that are mainly used to treat advanced cancers. They function by inhibiting one or more of the phosphoinositide 3-kinase (PI3K) enzymes, which are part of the PI3K/AKT/mTOR pathway. This signal pathway regulates cellular functions such as growth and survival. It is strictly regulated in healthy cells, but is always active in many cancer cells, allowing the cancer cells to better survive and multiply. PI3K inhibitors block the PI3K/AKT/mTOR pathway and thus slow down cancer growth. They are examples of a targeted therapy. While PI3K inhibitors are an effective treatment, they can have very severe side effects and are therefore only used if other treatments have failed or are not suitable.
The PI3K/AKT/mTOR pathway is an intracellular signaling pathway important in regulating the cell cycle. Therefore, it is directly related to cellular quiescence, proliferation, cancer, and longevity. PI3K activation phosphorylates and activates AKT, localizing it in the plasma membrane. AKT can have a number of downstream effects such as activating CREB, inhibiting p27, localizing FOXO in the cytoplasm, activating PtdIns-3ps, and activating mTOR which can affect transcription of p70 or 4EBP1. There are many known factors that enhance the PI3K/AKT pathway including EGF, shh, IGF-1, insulin, and CaM. Both leptin and insulin recruit PI3K signalling for metabolic regulation. The pathway is antagonized by various factors including PTEN, GSK3B, and HB9.
A CDK inhibitor is any chemical that inhibits the function of CDKs. They are used to treat cancers by preventing overproliferation of cancer cells. The US FDA approved the first drug of this type, palbociclib (Ibrance), a CDK4/6 inhibitor, in February 2015, for use in postmenopausal women with breast cancer that is estrogen receptor positive and HER2 negative. Several compounds are in clinical trials.
Dactolisib is an imidazoquinoline derivative acting as a PI3K inhibitor. It also inhibits mTOR. It is being investigated as a possible cancer treatment.
Perifosine is a former drug candidate that was under development for a variety of cancer indications. It is an alkyl-phospholipid structurally related to miltefosine. Perifosine interrupts the PI3K/AKT/mTOR pathway by acting as an allosteric AKT inhibitor targeting the pleckstrin homology domain of AKT. It was being developed by Keryx Biopharmaceuticals who had licensed it from Æterna Zentaris Inc.
Edelfosine is a synthetic alkyl-lysophospholipid (ALP). It has antineoplastic (anti-cancer) effects.
c-Met inhibitors are a class of small molecules that inhibit the enzymatic activity of the c-Met tyrosine kinase, the receptor of hepatocyte growth factor/scatter factor (HGF/SF). These inhibitors may have therapeutic application in the treatment of various types of cancers.
mTOR inhibitors are a class of drugs that inhibit the mechanistic target of rapamycin (mTOR), which is a serine/threonine-specific protein kinase that belongs to the family of phosphatidylinositol-3 kinase (PI3K) related kinases (PIKKs). mTOR regulates cellular metabolism, growth, and proliferation by forming and signaling through two protein complexes, mTORC1 and mTORC2. The most established mTOR inhibitors are so-called rapalogs, which have shown tumor responses in clinical trials against various tumor types.
A MEK inhibitor is a chemical or drug that inhibits the mitogen-activated protein kinase kinase enzymes MEK1 and/or MEK2. They can be used to affect the MAPK/ERK pathway which is often overactive in some cancers.
Sonidegib (INN), sold under the brand name Odomzo, is a medication used to treat cancer.
Triciribine is a cancer drug which was first synthesized in the 1970s and studied clinically in the 1980s and 1990s without success. Following the discovery in the early 2000s that the drug would be effective against tumours with hyperactivated Akt, it is now again under consideration in a variety of cancers. As PTX-200, the drug is currently in two early stage clinical trials in breast cancer and ovarian cancer being conducted by the small molecule drug development company Prescient Therapeutics.
Buparlisib is an experimental anti-cancer medication. It is a small molecule orally-available pan-class I phosphoinositide 3-kinase (PI3K) inhibitor. Buparlisib was under investigation as a treatment for advanced breast cancer but was abandoned due to negative results. It is still under investigation as a potential treatment for head and neck squamous cell carcinoma (HNSCC).
ABTL0812 is a small-molecule, experimental cancer drug being developed by Ability Pharmaceuticals.
Bisantrene, trademarked as Zantrene, is an anthracenyl bishydrazone with anthracycline-like antineoplastic activity. Bisantrene intercalates with and disrupts the configuration of DNA, resulting in DNA single-strand breaks, DNA-protein crosslinking, and inhibition of DNA replication. This agent is similar to doxorubicin in activity, but unlike anthracyclines like doxorubicin, exhibits little cardiotoxicity.
