Each year 14.1 million people are diagnosed with cancer all over the world. Unfortunately, some 8.2 million people doesn’t make it to fight another year. For most of others who does and for their families, life is not going to be a same as it was before. The fear that cancer would recur back, leaves patients with a heavy physiological torment. Some people find it’s very difficult to cope with this feeling and often get distressed and find their lives miserable.
Why cancer might come back
Cancer is characterized by uncontrolled growth of malignant cells which is trigged by DNA damage due to genetic or environmental reasons. Cancer cause tumors which consist of cancer cells. Doctors usually use chemotherapy and radiotherapy to fight cancer. In chemotherapy, drugs like Doxorubicin are used to kill cancer cells. Radiotherapy uses high energy ionizing radiation like X-rays, gamma rays and electrons to induce DNA damage of the cells. Unfortunately, none of these two techniques can kill every single cancer cells in the body. Doctors, can only try to lower the number of cancer cells in to a level that it’s difficult for them to recur back and killed by body’s own defenses. However, there can be cases cancer may recur due to replication of left over cells from the treatment. Also, in certain situations cancer cells can develop a resistance towards these treatments making it more difficult to kill them. Fortunately, doctors are now getting more equipped to handle cancer recurrence in this form due to numerous scientific and technological advances of the field.
In 1997, conclusive evidence was found about another, more disturbing type of cancer recurrence. Scientists observed, within the cancerous cells, a special type of cell exists with the characteristics associated with stem cells. These so called, “cancer stem cells” are tumor forming and more importantly have the ability to give rise to all other cancer cell types found in a particular cancer sample. These stem cells of cancer can exist as a distinct population among other cells and cause metastasis and give rise to new tumors. Unfortunately, these cells can be very elusive and most of the cancer drugs have no or little effect on them. This is primarily due to the fact that existing cancer treatments have mostly been developed and experimented on animal models targeting to tumor shrinkage as a primary objective. However, these animal models cannot provide a comprehensive picture of a human disease. Therefore, development of specific alternative treatment for cancer stem cells.
The smart nano bullet
Researchers at Ohio state University in USA have developed novel nanotechnology cancer drug based on biopolymeric chitosan nanoparticles which is designed to specifically attack cancer stem cells and preventing them from coming back. A large dose of a common chemotherapy drug called doxorubicin is encapsulated in to a chitosan shell. The chitosan shell permits, nanoparticle to bind to a specific receptor called CD44 in these cancer stem cells. This allows nanoparticle to infiltrate in to the cancer stem cell. Intercellular environment of these cancer cells are especially acidic, which dissolves the chitosan cell releasing the doxorubicin drug killing the cell.
The researchers have tested the drug on human breast tumors and on mice. The results were very encouraging showing that the cancer cell killing ability of this chitosan nanoparticle drug is six times more than that of normal doxorubicin drugs. The drug can also shrink the rest of the tumor with no evident side effects on the animals tested. This drug examples the remarkable ability of nanotechnology in cancer treatment where in the future doctors will be able to target specific cell types and giving further hope to people who recovering from the cancer for brighter tomorrow.
- Rao, Wei, Hai Wang, Jianfeng Han, Shuting Zhao, Jenna Dumbleton, Pranay Agarwal, Wujie Zhang et al. “Chitosan-Decorated Doxorubicin-Encapsulated Nanoparticle Targets and Eliminates Tumor Reinitiating Cancer Stem-Like Cells.” ACS nano(2015).
- Mukherjee, Siddhartha. “The Cancer Sleeper Cell”. New York Times. New York Times
- Bonnet D, Dick JE (July 1997). “Human acute myeloid leukemia is organized as a hierarchy that originates from a primitive hematopoietic cell”. Nature Medicine3 (7): 730–7.