Targeted cancer therapy is forms of therapy were using small molecules or other chemical substances, growth and proliferation of cancer cells are inhibited by disrupting the functions of a cancer cell. Scientists also call these small molecules as "molecular targeted drugs". US Food and Administration (FDA) have been approved many target therapies to treat many types of cancer.
Targeted cancer therapy focuses on particular molecular or structural changes in a specific type of cancer cell therefore targeted cancer therapy are more effective than any other cancer therapy like chemotherapy or radiotherapy.
Targeted Cancer therapy molecules can be divided in to three broad categories. Small molecules which can get into cancer cells and disrupts cells physiological functions and finally leading to cell death of cancerous cell are being used in Targeted cancer therapy. Another category targets the particular type of receptors which are only present in cancerous cells. Monoclonal antibodies are produced and used to target cancer cell receptors by doing so it interrupts signal transduction between neighbouring cells. Third category of molecules they Anti-angiogenesis drugs they inhibit the formation of blood vessels.
First Molecular Target for Targeted Cancer Therapy:
The first molecular target for the target therapy was Estrogen receptor. This receptor is required by many types of Breast cancer cells to propagate. When the Estrogen molecule binds to the Estrogen Receptor of the cell, it activated some genes which are required for the cell division and growth of the cancer cell.
FDA approved usage of selective estrogen receptor modulators such as Tamoxifen or Toremifene for the treatment of Estrogen receptor positive Breast cancer.
TARGETED CANCER THERAPY:
1) Signal transduction inhibitors:
• Protein-tyrosine kinase inhibitors such as Imatinib Mesylate
• Epidermal growth factor tyrosine kinase inhibitors like Genefitinib
2) Proteasome Inhibitors: Bortezomib
3) Monoclonal Antibodies:
Scientists identified cancer cell specific antigens in the body. Then these monoclonal antibodies which are specific to the particular type of cancer cell are produced in the laboratory.
These monoclonal antibodies go and bind to the cancer cell specific antigen and help in the destruction of cancer cells by Immune cells. Some of the monoclonal antibodies used in target therapy are
• Gemtuzumab ozogamicin
• Ibritumomab Tioxetan
Angiogenesis is the formation of blood vessels. Cancerous cells they need continuous supply of oxygen for their growth. Angiogenesis inhibitors inhibit the formation of blood vessels so that the cancer cells starve for oxygen and food at last leading to the death of cancer cells.
This group of compound are still in clinical trial stage. Scientists are hoping that Anti-angiogenesis compounds will be more effective in treating cancer.
Some of the FDA approved Targeted Therapy:
1) Imatinib mesylate have been approved to treat some patient with types of leukaemia and gastrointestinal stromal tumor.
2) Dasatinib have been approved to treat patients with acute lymphoblastic leukaemia and chronic myeloid leukaemia
3) Nilotinib have been approved to treat patients with chronic myeloid leukaemia
4) Trastuzumab have been approved to treat patients with breast cancer
5) Lapatinib have been approved to treat patients with metastatic breast cancer
6) Everolimus have been approved to treat patients with advanced kidney cancer.
7) Bevacizumab is a monoclonal antibody have been approved to treat patients with glioblastoma
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