Gene cells so the cancer treatments focused on

Gene transcription and DNA synthesis is strongly
dependent to protein kinases which have critical roles in signal transduction pathways
for transmission of information regarding extracellular or cytoplasmic
conditions in nucleus, by this way they affect the gene transcription.1  There are numerous of protein kinases
(around 550), on the other hand only few (130) protein phosphatases which
regulate the protein kinases activities.2

            Protein kinase enzymes transfer phosphate from ATP to
amino acid on the substrate specifically. This phosphorylation process leads to
signal-transduction pathway activity including lots of biologic processes such
as cell growth, differentiation etc. and the function is shown fig 1. Studies
have shown that there are deregulated, overexpressed protein kinases in tumor
cells so the cancer treatments focused on this pathway and investigating
selective and specific pharmacologic inhibitors. Protein kinase receptor
inhibitors are popular investigating for cancer treatments that mimicking the
adenine portion of ATP with their flat aromatic structure.2 In
fig. 2 mechanism of protein kinase receptor inhibitor is shown schematically.

The most popular studies are on BCR-ABL tyrosine
kinase which is directly affecting CML (chronic myelogenous leukemia). CML is a
life-threatening cancer, affecting marrow. There are hematologic stem cell
disorder observed which is result of abnormal DNA synthesis. Up to 2000s, the
only treatment is thought marrow transplantation. It is quite risky and finding
proper donor is really hard. Thus, other treatments are tried to apply such as
chemotherapy with Ara-C, hydroxyurea and interferon. However, patients were
suffering from side effects, so the breakthrough drug, “Gleevec” is

with other name is called “imatinib” is a tyrosine kinase receptor inhibitor
shown in fig.3 which is highly effective on CML and gastrointestinal stromal
tumors (GIST). Imatinib is approved by FDA for CML threatment in 2001 and
become a first-line treatment of CML in 2001.3 

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