Page 42 - AWSAR 2.0

18 || AWSAR Awarded Popular Science Stories - 2019
divide infinitely to form a cell mass (tumour) and evade the body’s natural cell death programmes, and while doing this, they disrupt cell-to-cell harmony. With time, some of the tumour cells gain the ability to detach and migrate through the blood to other parts of the body to form a new lump. This state is known as malignancy. Malignant cells are the most dangerous as they invade the healthy organs, disrupt their architecture and interfere with their normal functions. One important point to remember is that the initial change in the DNA of the healthy cell (which leads to a tumour formation) does not lead to the production of new molecular weapons but causes the cell’s molecular machinery to function abnormally. As the machinery is common and only the functioning is different, drugs targeting the cancer cells also damage the healthy cells of the body. This presents a major
challenge to scientists working in the field of cancer.
Although advancements
in research over the years
have helped in the discovery
of novel drugs with specific
targets, we still lack the
fundamental understanding of
the line discriminating cancer
cells from non-cancer cells. To
add more to the trouble, a few
cancer cells can adapt during
the therapy and find a way to
evade the effects of the drugs,
which is commonly referred to
as drug resistance. In the end,
here, we can understand that for every tissue and organ to function properly, it must maintain proper architecture, size and coordinates with other cells in the tissue. Cancer cells precisely disrupt all of that, especially when they start migrating.
Understanding multidrug resistance
Mostly, we have heard the term multidrug resistance (MDR) in the context of microbial infections, where germs become resistant against one type or dose of an antibiotic. To combat this, physicians generally increase the dose of drugs or change their types, and in some cases, use multiple drugs. MDR in cancer is conceptually very similar where either the cancer cells become resistant over time or a few resistant cells get selected against the drug being used. It is also one of the main reasons for the relapse of cancer. During primary therapeutic treatment, although many cancer cells die, a few cancer cells adapt and evade the effect of the drug with the help of specific intracellular mechanisms. “Intracellular mechanism” is a process carried by some complex, but co-ordinated chemical reactions
known as “signal transduction.” “Signal transduction” is a complex set of networks of thousands of ordered chemical reactions performed mainly by proteins and is required for the proper functioning of a cell. It is tightly regulated by the cell’s DNA and responds to internal and external chemical cues/ signals. Now, we return to the mechanisms that lead to MDR. As this mechanism can render simultaneous resistance to more than one drug, it is called MDR. The profuse secretion of the therapeutic drugs out of the cell, chemical modification of
the drug molecule to neutralize its effect and excessive synthesis of anti-death proteins are some of the common mechanisms responsible for MDR.
Most of us in the past have had a family, friends, or heard of someone being diagnosed with cancer. The deadly nature of the disease can be realized from the fighting stories of patients with cancer. The data published last year by the World Health Organization indicated that cancer was the second largest cause of deaths in India after heart diseases.