Studying how skin cancer starts

August 13, 2020

CLEVELAND--Luis Ortiz-Rodríguez grew up on the beaches of Puerto Rico--surfing, swimming and running in the hot sand--and swears he had never put on sunblock a day in his life.  

Then the day came when he peered through an ultrafast laser spectrometer at the College of Arts & Sciences at Case Western Reserve University and observed and recorded pre-cancerous lesions forming on the DNA within three picoseconds after exposure to ultraviolet light.  

That's picosecond, as in one trillionth of a second.  

"It's amazing how quickly this happens," said Ortiz-Rodríguez, a PhD researcher in chemistry at Case Western Reserve University. "And it's true, when I was younger, I was always running shirtless on the beach or surfing and I thought sunblock was just for old people. Not anymore."  

New research by Ortiz-Rodríguez and mentor Carlos Crespo, a professor and lead researcher in the The Crespo Group lab, reveals for perhaps the first time how quickly certain pre-cancerous lesions can form on the DNA of our skin when exposed to sunlight.  

"That's important," Ortiz-Rodríguez said, "because we need and want to know how fast the mutations can form in the DNA, so that maybe researchers can find a better way to prevent skin cancer at a cellular level."

The 6-4 photo adducts mutation

Their research, recently published in the journal Nature Communications, shows how they've detected fast-forming mutations--called "DNA (6-4) photo adducts" by scientists." Photo adducts are lesions formed by a light-induced reaction in cellular DNA, which can lead to skin cancers. (The numbers 6-4 refers to the location of the relevant segment of DNA, see illustration at bottom).

Previous research published in Science by Crespo and collaborators has shown the other primary photo adduct linked to skin cancers, the thymine-thymine cyclobutane photo adduct, forms in less than 1 picosecond. But this work is the first to defined so precisely the formation mechanism of the 6-4 photo adduct.  

They believe their findings will provide a stepping-stone toward a fuller understanding of how skin cancerous lesions actually form--a discovery that Crespo believes could have a big impact on the economics of treating and preventing skin cancer.  

Skin cancer costs

With over 5 million cases diagnosed in the United States each year, skin cancer is America's most common cancer, according to the Skin Cancer Foundation, and the annual cost of treating skin cancers in the United States is about $8.1 billion.

The research also affirms that while most of us don't worry about the occasional sunburn because the discomfort fades in a few days, the longer-term damage stays hidden for decades, Crespo said.  

"You're forming these mutations in your skin every second that you are exposed to sunlight, but enzymes in your cells repair more than 99% of them," Crespo said. "The problem is the less than 1% that remains un-repaired because they can accumulate in your body, often until you're much older and then they can lead to skin cancers."

The search for these precursors to skin cancer has actually been going on in earnest since the late 1960s, Crespo said. Until now, the timescale of its formation and the reactive-state precursor had eluded researchers around the world.  

"Even though it is well established that formation of the 6-4 photo adduct is an initial pre-cancer lesion leading to skin cancer, we didn't fully understand the mechanistic aspects of it formation, so our paper provides important information in the characterization and understanding of these reactions," Crespo said. "Understanding the chemical processes could help us design better sunblock or maybe avoid the damage to the DNA before it occurs."  
-end-
Case Western Reserve University is one of the country's leading private research institutions. Located in Cleveland, we offer a unique combination of forward-thinking educational opportunities in an inspiring cultural setting. Our leading-edge faculty engage in teaching and research in a collaborative, hands-on environment. Our nationally recognized programs include arts and sciences, dental medicine, engineering, law, management, medicine, nursing and social work. About 5,100 undergraduate and 6,700 graduate students comprise our student body. Visit case.edu to see how Case Western Reserve thinks beyond the possible.

Case Western Reserve University

Related DNA Articles from Brightsurf:

A new twist on DNA origami
A team* of scientists from ASU and Shanghai Jiao Tong University (SJTU) led by Hao Yan, ASU's Milton Glick Professor in the School of Molecular Sciences, and director of the ASU Biodesign Institute's Center for Molecular Design and Biomimetics, has just announced the creation of a new type of meta-DNA structures that will open up the fields of optoelectronics (including information storage and encryption) as well as synthetic biology.

Solving a DNA mystery
''A watched pot never boils,'' as the saying goes, but that was not the case for UC Santa Barbara researchers watching a ''pot'' of liquids formed from DNA.

Junk DNA might be really, really useful for biocomputing
When you don't understand how things work, it's not unusual to think of them as just plain old junk.

Designing DNA from scratch: Engineering the functions of micrometer-sized DNA droplets
Scientists at Tokyo Institute of Technology (Tokyo Tech) have constructed ''DNA droplets'' comprising designed DNA nanostructures.

Does DNA in the water tell us how many fish are there?
Researchers have developed a new non-invasive method to count individual fish by measuring the concentration of environmental DNA in the water, which could be applied for quantitative monitoring of aquatic ecosystems.

Zigzag DNA
How the cell organizes DNA into tightly packed chromosomes. Nature publication by Delft University of Technology and EMBL Heidelberg.

Scientists now know what DNA's chaperone looks like
Researchers have discovered the structure of the FACT protein -- a mysterious protein central to the functioning of DNA.

DNA is like everything else: it's not what you have, but how you use it
A new paradigm for reading out genetic information in DNA is described by Dr.

A new spin on DNA
For decades, researchers have chased ways to study biological machines.

From face to DNA: New method aims to improve match between DNA sample and face database
Predicting what someone's face looks like based on a DNA sample remains a hard nut to crack for science.

Read More: DNA News and DNA Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.