The Price of Immortality - Story of HeLa Cells

I remembered very little from undergrad Biology courses about HeLa cells when I started reading the UNC School of Med's summer reading: The Immortal Life of Henrietta Lacks, but upon finishing the book, there are certain mind-blowing concepts that I just have to jot down. First of all, a quick summary of the story: In 1951, a 31-year old African-American lady by the name of Henrietta Lacks went to Johns Hopkins Hospital for what she felt was a 'knot' in her stomach. She was diagnosed with cervical cancer, and doctors began treatment for her cancer. The story gets interesting though, because when doctors saw the incredible rate at which her tumor had spread, they took a sample of her tumor without consent. The cells from the sample were cultured and much to the surprise of the researchers, these cells kept on growing and reproducing, when provided with the proper cell survival conditions. Henrietta Lacks died within a few months after being diagnosed, while her cancer cells continued to thrive and achieved 'immortality'.

Now for decades, scientists and researchers were using the HeLa cells (abbreviated for the patients first and last names) in cancer research, to help develop the polio vaccine, for AIDS research, to see the impact of zero-gravity space conditions on human cells, etc. .. while Henrietta Lacks's family had no clue a part of her was still alive. When her children found out, they were naturally outraged on a number of levels: a) that their mother's cells had been taken without consent, b) that companies were profitting from the research done with these cells while they themselves were barely making ends meet, c) that no one had even told them for years that Henrietta's cells were being used, and so on. The book went into detail about the family, their reactions, and their desire to inform others about their mother - a very interesting aspect to the HeLa story that most Biology students don't get to see.

However, what absolutely blew me away was the reason for the HeLa cell immortality. Now, cancer cells are basically cells that continue dividing when they should have stopped. Whether grown in culture or in the human body, normal human cells are preprogrammed to die after a certain number of cell divisions. According to the Hayflick Limit, that number is 50 for most cells. After 50 cell divisions, normal cells usually undergo preprogrammed cell death (apoptosis). Because of this limitation on cell division, normal non-cancerous human cells never survived on culture when scientists tried to use them to grow an immortal cell line.

So how does a normal cell become cancerous? When a virus or genetic mutation transforms the cell, it can become immortal. In the case of Henrietta Lacks, she had been infected by a very deadly strain of the Human Papilloma Virus (HPV), HPV-18. This virus inserted its DNA into Henrietta's 11th chromosome and turned off her p53 tumor suppressor gene.

Now for the cancer mechanism: Everytime a normal cell divides, there is a chain of DNA at the end of each chromosome, called a telomere, that is shortened a little per division. When they've divided, oh say 50 times, the telomere part has almost disappeared entirely, so the cell stops dividing and dies. Cancer cells have an enzyme called telomerase that keep on rebuilding the telomeres. So the telomeres are never shortened, and the cell doesn't undergo cell death. "This explained the mechanics of HeLa's immortality: telomerase constantly rewound the ticking clock at the end of Henrietta's chromosomes so they never grew old and they never died" (Skloot, 209).

Okay, so this is the thought I can't get out of my head: so as we age, our normal cells undergo aging, the telomeres on the ends of our chromosomes get shortened, and soon the cells die, which eventually leads to dysfunction in our different body systems and thus to our death. Telomerase on the other hand, prevents telomeres from shortening. So, this is such a long shot, but could it be possible to prolong human life if we discovered a way to synchronize the extension of telomeres on all our chroosomes in our cells? Aaahh..mind-blowing, right? Several decades ago, even the thought of cell immortality was unthinkable, but HeLa has proven it possible. Could it be that further research can provide insight into human immortality? But what a fine line, right? Extend telomeres just enough on just the right cells - live longer. But if all the wrong cells start living longer than they're supposed to - boom, it's cancer. The very HeLa cells that proved immortal were the ones that drastically shortened Henrietta Lacks's life. On one side you have rapidly-growing cancer, on the other - immortality.

Signs of New Beginnings

After what has felt like an eternity of waiting, in just 2 short weeks, I will finally be starting medical school at UNC-Chapel Hill. And my good friend Nawsheen suggested that I absolutely have to start blogging about the experiences to ensue.

So I took her advice and how's this for a sign: as I was creating this new blog, it prompted me to write in the random word that came up on screen and that word was 'healin'. And one thing led to another, and I couldn't help but set the words 'TarHealer' in the URL. Haha..clever, I know.

Anyway, as excited as I am to embark on this long-awaited journey, I cannot believe how much has happened over the past few months and it saddens me that so much has to come to an end. (End of undergrad, my best friend getting married and moving hundreds of miles away, deciding to move into an apartment closer to campus and thus further from my family). Nonetheless, I am anxiously awaiting my first day of medical school and all the excitement and even obstacles that it will bring.