What are ‘Zombie Cells’ and what is their relationship with human age?

Zombie cells do not die easily and they grow with age. Such cells can also be beneficial for health because they reduce risk of nearby cells turning into cancer cells and also attract resistant cells to remove the cancer cells.

According to cytology, abnormal changes in human cells can turn them into cancer cells. Changes caused by damage to genetic material cause mutations that cause cell division to become uncontrolled, leading to cancer. But damage at the end of chromosomes in cells can cause zombie cells. These are the cells that are alive, but are unable to function.

Before division, the DNA of cells binds to proteins to form chromosomes that support genetic material. But upon cell division, these telomeres become shorter, thus reducing their ability to preserve DNA. According to research published in Nature Structural and molecular Biology, in such a loss, mutations occur in the genetic material and it can result in cancer.

Human cells avoid becoming cancer cells when their telomeres become too short due to many divisions and they are at increased risk of damage. But going into the zombie-like state, the division stops by the process of cellular senescence. Due to resistance to death or extinction, such zombie cells start accumulating with age. They protect cells from the risk of becoming cancer cells and attract resistance cells. So that cancer cells can be cleared. But they can also promote tumor growth by inhibiting healing.

The researchers wanted to know whether direct damage to telomeres is sufficient to produce zombie cells. They added proteins to the telomeres of human cells grown in the lab, after which they added dye to the proteins, which made them sensitive to light. When exposed to light, cells produce protein co-oxygen free radicals that damage DNA.

Researchers found that direct damage to telomeres is enough to make zombie cells. This happens even when the protective cover is not short. Telomeres shorten with age. They limit the frequency of division by making zombie cells when they reach a certain length, but the effect of free radicals accelerates the process of telomere shortening. Due to which many diseases give birth to cancer.

Researchers are studying their treatment etc. to protect telomeres from damage and to prevent the accumulation  of zombie cells. Several studies have shown that removing zombie cells can promote healthy aging. This can also improve functioning of the brain. Researchers have also developed drugs that kills zombie cells. But this study has focused more on the consequences of this telomere loss. Now the researchers will study the effects on the other cells.