HeLa cell line is a human cancer cell line that does not undergo apoptosis or cell death, and can be continuously cultured indefinitely in-vitro (AccessScience Editors [ASE] 2014). In general, human somatic cell cultures cannot be maintained in laboratory conditions beyond certain no of generations. Hence, HeLa cells are very useful in medical research for studying cell behavior and cell death, in developing new cancer therapies and vaccines. Since their initial culturing, HeLa cells have been cloned several times, and distributed throughout the world for various research purposes. Though today several immortalized cell lines are available, HeLa still remains the most widely used one (Collins 2013).
The initial sample of HeLa cells was obtained from the biopsy of a cervical tumor patient, Henrietta Lacks in 1951 (AccessScience Editors 2014). The cell line derived its name from the first and last name of its contributor. HeLa cervical tumor cells are entirely different from normal human somatic cells in several aspects. Instead of 46 chromosomes, HeLa cells have 76 or 80 chromosomes that have undergone mutation due to Human Papilloma Virus (HPV) infection (Carpio 2014). HPV infection in a host cell would lead to suppression of genes coding for the guardian protein synthesis, and it is the major cause for cervical cancer. Guardian protein (p53) is responsible for mutation repair and tumor inhibition (Carpio 2014). Further, the rapidly multiplying property of HeLa cells is attributed to their over-active telomerase enzymes. Telomere ends in normal cell chromosomes get shortened after each generation and finally lead to cell death. However, in HeLa cells the telomeres are effectively rebuilt by the telomerases, and cell aging is prevented (Carpio 2014).
As HeLa cells grow rapidly, more cells can be harvested in a very short time and the cell’s large size makes them ideal for cell imaging studies (Carpio 2014). Hence, HeLa cells allow cellular processes such as replication, apoptosis and cell organelles to be studied in depth. Also, they are very useful in gene expression studies as large quantities of the desired protein can be obtained from them (Carpio 2014). HeLa cells can be infected by viruses and used in the development of vaccines. Polio vaccine was developed in 1953 well within a year of experimenting on poliomyelitis virus infected HeLa cells (Carpio 2014). In fact HeLa helped scientists understand that normal human cells have only 46 chromosomes, and also decipher the mechanism of HPV induced cervical tumor development (Carpio 2014). HeLa cells are also used to research AIDS, cancer, radiation effects on human cells, as well as understand the mechanism of genetic disorders (Carpio 2014).
However, due to their wide spread usage HeLa cells have become a common contaminant in laboratories researching on human cell lines (ASE 2014). Contamination would lead to invalidation of any result obtained in a study. Also, in 1951 when the cells were obtained from Henrietta Lacks, she was not informed of its usage for purposes other than her disease diagnosis (Carpio 2014). So, no informed consent was obtained from the donor. Further, when HeLa genome data was made available for widespread access, Lacks’s private genetic data could longer be kept confidential (Carpio 2014). Though HeLa was a boon to medical research, its usage violated several ethical principles and rights. However, today access to HeLa genomic data is restricted, and its usage is highly regulated following concerns raised by Henrietta Lack’s family members (Carpio 2014).
The contamination issues and ethical concerns forced researchers to find alternative human cell lines. Basically, HeLa is only a cancer cell line with abnormal chromosomes, and its genetic expression is not close to normal human cells. Other cell lines such as IMR-90 derived from fetal lung tissue that are closer to normal human cells are rapidly replacing HeLa despite having only a finite lifespan (Carpio 2014). Still HeLa would remain the most exploited cell line in biotechnology research, as scientists have deciphered a lot about complex cellular mechanisms only with these living tools.
References
ASE. 2014. Importance of HeLa cells. [accessed 2016 Feb 6]. http://www.accessscience.com/
content/importance-of-hela-cells/br0826141
Carpio AD. 2014. The good, the bad, and the HeLa - The Berkeley Science Review. The
Berkeley Science Review. [accessed 2016 Feb 6]. http://berkeleysciencereview.com/
article/good-bad-hela/
Collins F. 2013 Jul. HeLa Cells: A New Chapter in An Enduring Story. NIH Directors Blog.
[accessed 2016 Feb 6]. http://directorsblog.nih.gov/2013/08/07/hela-cells-a-new-chapter-in-an-enduring-story/
