Cancer is a deadly disease that has caused the deaths of many people all over the world. Prior to the Coronavirus pandemic, it was the most damaging ailment affecting mankind. In the US alone, over 1.7 million people in 2017 developed cancer, with over 600,000 deaths, according to the Center for Disease Control (CDC). The most common cancers are breast cancer, lung cancer, prostate cancer, and melanoma of the skin. Over the past few decades, science has made remarkable progress in cancer research, but the disease is still a menace.However, a new study examines the relationship between telomeres, and how it may help prevent cancer.
So what are telomeres? Simply said, they are the caps at the end of DNA strands. They help protect the DNA within chromosomes from being damaged, and may prevent “interchromosomal fusion.” Telomeres become shorter as a person ages. The head of Laboratory Cell Biology and Genetics at Rockefeller University, Titia de Lange, has studied the role of telomeres in cancer control. “Telomeres protect the genetic material,” she explains. “ The DNA in telomeres shorten when cells divide, eventually halting cell division when the telomere reserve is depleted.” In most cells, when the cell is unable to divide due to depleted telomeres, it dies. But, cancer cells trigger an enzyme called telomerase. Telomerase prevents telomere shortening, and the cell can divide indefinitely.
This means that the abnormal cells are allowed to replicate, and that’s how a tumor forms. Sometimes the tumor is benign or noncancerous, but at times they are malignant or cancerous and continue to grow and spread. As many as 100 billion human cells die, and new ones replace them every day. Normally this poses no issues, but at times, DNA mutations occur, which results in abnormal cells. That is how cancer can occur. “Most clinically detectable cancers have re-activated telomerase, often through mutation,” explains de Lange.
For decades, de Lange has studied telomeres, and the idea that telomere shortening could help prevent cancer is not new. But this is the first time a researcher has found proof that telomere shortening can prevent cancer.
De Lange received help from doctors at Radboud University Medical Center in Holland, who were familiar with her research. They got in touch with her to share information about Dutch families with a “striking family history of cancer.” These families had a mutation of the TINF2 gene, which controls the TIN2 protein, which is responsible for telomere length.
At the de Lange lab, a Women & Science postdoctoral fellow, Isabelle Schmutz, created cells with this mutation. At first, the cells appeared healthy, but scientists noticed an issue with the telomeres. According to de Lange, the telomeres were too long, and commented that the telomeres of the patients were “ far above the 99th percentile.” De Lange explained that “ the data show that if you are born with long telomeres, you are at greater risk of getting cancer.”
“We are seeing how the loss of the telomere tumor suppressor pathway in these families leads to breast cancer, colorectal cancer, melanoma, and thyroid cancers. These cancers would normally have been blocked by telomere shortening. The broad spectrum of cancers in these families shows the power of the telomere tumor suppressor pathway.”
The telomere shortening study could help in cancer prevention and treatment options in the future. But, de Lange points out that the new research on telomeres are only relevant during early fetal development, presently. De Lange wrote. “ We imagine that the TINF2 mutations exert their cancer-promoting effects in the first weeks or months after fertilization. TINF2 would be a tumor suppressor gene with a very specific window of opportunity, exerting its effect early in development but not later.” Still, it is a breakthrough development in cancer research, and a stepping stone to greater discoveries.
De Lange adds, “How telomeres are regulated is a fundamental problem, and by working on a fundamental problem, we were eventually able to understand the origins of a human disease.” As we progress in scientific research, we can only hope that one day, diseases like cancer, will be prevented and hopefully eliminated.
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