Introduction: Overcoming Adversity to
Make Scientific History
Rita Levi-Montalcini’s journey to scientific acclaim is a
story of resilience and brilliance against the backdrop of political and
personal challenges. After earning her medical degree from the University of
Turin in 1938, Levi-Montalcini's promising career was suddenly stifled by
Mussolini's 1939 decree, which barred non-Aryan Italians from pursuing
professional careers. Undeterred, she set up a small laboratory in her home and
began independent research, drawing inspiration from the work of Viktor Hamburger,
a renowned scientist in the field of developmental biology. Her pioneering
research laid the foundation for groundbreaking discoveries that would forever
change our understanding of cellular growth and development.
Discovering Nerve Growth Factor (NGF)
In 1947, Levi-Montalcini took her research to new heights
when she joined Viktor Hamburger at Washington University in St. Louis,
Missouri. Here, she studied nerve tissue growth, continuing her focus on chick
embryos. In 1948, she made a pivotal discovery: when a piece of a mouse tumor
was grafted onto chick embryos with their wing buds removed, nerve growth was
significantly stimulated in the surrounding tissue. This unexpected result
marked the beginning of an entirely new field of research in neurobiology.
In 1953, Levi-Montalcini was joined by biochemist Stanley
Cohen, who played a crucial role in isolating the active protein from the tumor
tissue. Together, they identified and named the protein nerve growth factor
(NGF). This discovery revealed that NGF is essential for the growth,
maintenance, and survival of nerves in the peripheral nervous system (outside
the brain and spinal cord), as well as for certain cholinergic nerves in the
brain.
The Discovery of Epidermal Growth
Factor (EGF)
Stanley Cohen continued to build on the discoveries he and
Levi-Montalcini had made. In 1959, after moving to Vanderbilt University, Cohen
isolated another significant growth factor from the NGF-containing tumor. This
protein was found to stimulate the growth of the epidermal layer of skin and
had a remarkable effect on newborn mice, causing them to open their eyes
earlier than normal. Cohen named this newly discovered protein epidermal
growth factor (EGF). The discovery of EGF, like NGF, revealed the immense
potential of growth factors in regulating various biological processes.
Nobel Prize Recognition for Their
Revolutionary Work
The groundbreaking work of Rita Levi-Montalcini and Stanley
Cohen did not go unnoticed. In 1986, both scientists were awarded the Nobel
Prize in Physiology or Medicine for their pioneering discoveries of growth
factors. Their contributions have had an enduring impact on cell biology and
medicine, further establishing the critical role of proteins in cellular
development.
The Rise of Growth Factors: A
Revolution in Cellular Biology
NGF was the first of approximately fifty growth-promoting
agents identified in biological research. These growth factors are secreted by
various tissues in the body and serve as signaling molecules between cells.
They play a crucial role in stimulating cellular growth, replication, and
differentiation (the process by which cells become specialized). Growth factors
are not only present in humans but have also been identified in a wide range of
organisms, including plants, insects, and vertebrates.
The discovery of growth factors has revolutionized medical
treatments. These proteins are now used to treat a variety of conditions,
including cancers, blood disorders, and cardiovascular diseases. One of the
most well-known growth factors is erythropoietin (EPO), which is
produced in the kidneys and stimulates the production of red blood cells. EPO’s
impact extends beyond medicine, as it has also gained notoriety in the world of
sports, where it is sometimes used as a blood doping agent to enhance
performance, particularly in endurance sports like cycling.
Conclusion: A Legacy of Scientific
Innovation
The work of Rita Levi-Montalcini and Stanley Cohen has left
an indelible mark on the field of biology, with their discoveries shaping the
way scientists understand cellular development and growth. From the
identification of NGF and EGF to the broader implications of growth factors in
medicine, their work continues to influence medical treatments and scientific
research today. Their contributions not only exemplify the power of
perseverance and collaboration but also serve as a testament to the
transformative power of discovery in the life sciences.
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| Among the fifty-or-so growth-promoting factors that have been discovered since 1953, perhaps the most well known is erythropoietin (EPO), which stimulates red blood cell production. EPO has gained a notorious reputation as a blood-doping agent, increasing oxygen delivery to muscles, which enhances endurance performance. |
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