Context: The researchers at the Indian Institute of Science have developed a new way to deliver cancer vaccines using the body's natural transport system.
They have developed an antigen that can attach itself to a natural protein called serum albumin in the blood and travel to the nearest lymph node, where the immune system is activated. This method avoids the need for artificial carriers that can cause side effects and allows for more targeted delivery of cancer vaccines.
Bio-taxis:
- Bio-taxis, also known as targeted drug delivery or targeted therapy, is a developing area of cancer treatment that utilises the body's natural transport mechanisms to deliver therapeutic agents directly to cancer cells.
- The goal of bio-taxis is to enhance the effectiveness of treatment while reducing the side effects associated with traditional chemotherapy (minimising the damage to healthy cells).
- One example of bio-taxis for cancer treatment involves the use of antibodies or nanoparticles that are designed to bind to specific molecules on the surface of cancer cells. These targeted therapies can attach to/hitchhike on proteins in the bloodstream, such as serum albumin, until they reach their target. Once they reach the tumour, the therapeutic agents can be released to kill the cancer cells.
Cancer cells and their detection:
- Cancer is a condition where cells grow and divide uncontrollably due to a disruption in their DNA.
- Normally, our immune system fights against invaders using antibodies produced in the lymph nodes, which are small organs in the human body. Antigens are molecules that trigger the production of antibodies to fight invaders (trigger immune response).
- In the case of cancer, the cancer cells are clever (they evade the immune system) and can shut down the production of antibodies that target and eliminate them.
- To develop a cancer vaccine, scientists modify or mimic an antigen found on the surface of cancer cells to turn up or turn on this antibody production. These antigens can prod the immune system into producing antibodies. But how to take the antigens to the lymph nodes?
How to carry antigens to lymph nodes?
- Traditionally, delivering cancer antigens (molecules that trigger immune response) to lymph nodes involved hitching them onto artificial carriers like viruses or proteins. However, these carriers can be bulky, cause side effects, and even sometimes hinder the immune response (reduce the production of antibodies against cancer cells).
- The new approach uses the body's natural transport system. Scientists designed an antigen with a special attachment that allows it to bind to serum albumin, the most abundant protein in blood plasma. This "hitchhiking" on albumin carries the antigen directly to lymph nodes, where immune system activation happens. This method is simpler and avoids the problems associated with artificial carriers.
- They synthesised a specific carbohydrate called Tn, which is found on the surface of various cancer cells, in the laboratory.
- They combined this carbohydrate with a long-chain chemical that has an affinity for oils, creating bubble-like structures called micelles. These micelles strongly bind to human serum albumin.
- When the micelle latches onto albumin, it breaks apart, and the individual antigen molecules bind to the available albumin.
- This finding suggests that there may not be a need to search for viruses, proteins, or other carriers because serum albumin alone can effectively transport the antigens. This breakthrough provides a new way to deliver cancer vaccines.
Carbohydrate-based antigens:
- In recent years, scientists have been focusing on carbohydrates found on the surfaces of cancer cells to develop these antigens.
- Both normal and cancer cells have carbohydrates on their surfaces, but cancer cells have heavily truncated (shortened) carbohydrates.
- Hence, Carbohydrate-based antigens can play a crucial role in the development of cancer vaccines.