Bacterial therapy of cancer

Background: Cancer is characterized by uncontrolled and invasive growth of cells. These cells may spread to other parts of the body, and this is called metastasis.Although conventional anticancer therapies, consisting of surgical resection, radiotherapy and chemotherapy, are effective in the management of many patients but for about half of cancer sufferers these are ineffective, so alternative techniques are being developed to target their tumours. Spontaneous tumors regression has been associated with microbial infection for 100s of years and inspired the use of bacteria for anticancer therapy. Dr. William B. Coley (1862–1936), a bone- sarcoma surgeon, was a pioneer in treating his patients with both live bacterial-based and mixture of heat-killed bacteria known as Coley’s toxins. Bacterial therapies have an advantage over passive drug molecules because they can actively target intratumoral microenvironments with preferential growth and active motile transport. The ideal criteria for the selection of therapeutic bacteria are as follows: Non toxic to the host; selective for a specific type of tumor; has the ability to penetrate deeply into the tumor where ordinary treatment does not reach; non immunogenic (does not trigger an immune response immediately but may be cleared by the host); harmless to normal tissue; able to be manipulated easily; and has a drug carrier that may be controlled. Several bacterial species have inherent ability to colonize solid tumors in vivo. However, their natural anti-tumor activity can be enhanced by genetic engineering that enables these bacteria express or transfer therapeutic molecules into target cells.Conclusion: Once perfected, anticancer bacteria are expected to be an essential clinical tool, able to carry out functions that are unachievable by other therapies, and which can detect, prevent, and treat tumors. Since cancer is a multifactorial disease no single therapy is completely suitable for it. Combination of recombinant DNA technology along with immunotherapy applied to the anaerobic bacteria will serve as the foundation for the multimodality therapeutic strategies for cancer.

Keywords:

bacterial , therapy , cancer