Nav: Home

Retroviral RNA may play a part in liver cancer

October 28, 2015

An international group led by RIKEN in Japan and INSERM in France have found that retroviral long-terminal-repeat (LTR) promoters--a type of repetitive element that are widely distributed in the human genome--are highly activated in hepatocellular carcinomas, the most common type of liver cancer. Intriguingly, these areas--which are particularly activated in HCCs associated with viral hepatitis, are not normally activated in the liver but are in reproductive tissues such as testis and placenta. The study, published in Genome Research, suggests that the activation of LTR promoters might contribute to the development of cancer in the liver.

Retroviral LTRs are widely believed to be the remnants of retroviruses--like the HIV virus--which lost the ability to exit from cells and became parasitic elements in the genome. "Since these viral elements contain elements that are capable of functions such as transcription" says Piero Carninci of the RIKEN Center for Life Science Technologies, one of the corresponding authors, "it seems that organisms have sometimes made use of these LTRs for their own purposes, and in fact they are highly activated in reproductive tissues and, as we discovered earlier, in ES and iPS cells."

The group used CAGE technology, a technique developed at RIKEN, to examine RNA expression in liver cancer tumors and non-tumor tissue taken from the same patients. They found 4,756 non-coding promoters that were more highly activated in the tumor tissue than the non-tumor tissue, and remarkably, 935 of these were located in retroviral LTRs (Fig. 1).

Then, examining the causes and aggressiveness of the tumors, they found that the activation of LTR promoters correlated both with the cause of the tumor--differing in patients whose cancer was associated with hepatitis B, hepatitis C, or alcohol use--and with the progression--less differentiated tumors with a higher chance of recurrence, had higher levels of expression (Fig. 2). "The fact that different patterns were found in tumors of different etiologies suggests that these are not simply random activations but may be part of the mechanism through which the cancer arose," says Kosuke Hashimoto, the first author of the paper. Using a mouse model of HCC, they also found that 18.9% of the upregulated non-coding promoters were located in LTR elements (Fig. 1), and that the expression was higher in more advanced tumors (Fig. 3). "It appears," says Hashimoto, "that we are seeing a similar phenomenon in both the mouse and humans."

The group plans to continue research to uncover the function of the various LTRs to be able to put together a picture of how they contribute to the emergence of cancer. "We hope," says Carninci, "that this work could lead to a better understanding of the mechanism of hepatocellular carcinoma and to the identification of biomarkers that could be used as diagnostic tests. This is very important considering that liver cancer is the second largest cause of cancer deaths in the world, killing more than 700,000 people every year."
-end-


RIKEN

Related Cancer Articles:

Radiotherapy for invasive breast cancer increases the risk of second primary lung cancer
East Asian female breast cancer patients receiving radiotherapy have a higher risk of developing second primary lung cancer.
Cancer genomics continued: Triple negative breast cancer and cancer immunotherapy
Continuing PLOS Medicine's special issue on cancer genomics, Christos Hatzis of Yale University, New Haven, Conn., USA and colleagues describe a new subtype of triple negative breast cancer that may be more amenable to treatment than other cases of this difficult-to-treat disease.
Metabolite that promotes cancer cell transformation and colorectal cancer spread identified
Osaka University researchers revealed that the metabolite D-2-hydroxyglurate (D-2HG) promotes epithelial-mesenchymal transition of colorectal cancer cells, leading them to develop features of lower adherence to neighboring cells, increased invasiveness, and greater likelihood of metastatic spread.
UH Cancer Center researcher finds new driver of an aggressive form of brain cancer
University of Hawai'i Cancer Center researchers have identified an essential driver of tumor cell invasion in glioblastoma, the most aggressive form of brain cancer that can occur at any age.
UH Cancer Center researchers develop algorithm to find precise cancer treatments
University of Hawai'i Cancer Center researchers developed a computational algorithm to analyze 'Big Data' obtained from tumor samples to better understand and treat cancer.
New analytical technology to quantify anti-cancer drugs inside cancer cells
University of Oklahoma researchers will apply a new analytical technology that could ultimately provide a powerful tool for improved treatment of cancer patients in Oklahoma and beyond.
Radiotherapy for lung cancer patients is linked to increased risk of non-cancer deaths
Researchers have found that treating patients who have early stage non-small cell lung cancer with a type of radiotherapy called stereotactic body radiation therapy is associated with a small but increased risk of death from causes other than cancer.
Cancer expert says public health and prevention measures are key to defeating cancer
Is investment in research to develop new treatments the best approach to controlling cancer?
UI Cancer Center, Governors State to address cancer disparities in south suburbs
The University of Illinois Cancer Center and Governors State University have received a joint four-year, $1.5 million grant from the National Cancer Institute to help both institutions conduct community-based research to reduce cancer-related health disparities in Chicago's south suburbs.
Leading cancer research organizations to host international cancer immunotherapy conference
The Cancer Research Institute, the Association for Cancer Immunotherapy, the European Academy of Tumor Immunology, and the American Association for Cancer Research will join forces to sponsor the first International Cancer Immunotherapy Conference at the Sheraton New York Times Square Hotel in New York, Sept.

Related Cancer Reading:

The Cancer-Fighting Kitchen, Second Edition: Nourishing, Big-Flavor Recipes for Cancer Treatment and Recovery
by Rebecca Katz (Author), Mat Edelson (Author)

The Emperor of All Maladies: A Biography of Cancer
by Siddhartha Mukherjee (Author)

Anticancer: A New Way of Life
by David Servan-Schreiber MD PhD (Author)

F*ck Cancer: A totally inappropriate self-affirming adult coloring book (Totally Inappropriate Series) (Volume 4)
by Jen Meyers (Author)

Chris Beat Cancer: A Comprehensive Plan for Healing Naturally
by Chris Wark (Author)

The Truth about Cancer: What You Need to Know about Cancer's History, Treatment, and Prevention
by Ty M. Bollinger (Author)

The Metabolic Approach to Cancer: Integrating Deep Nutrition, the Ketogenic Diet, and Nontoxic Bio-Individualized Therapies
by Dr. Nasha Winters ND FABNO L.Ac Dipl.OM (Author), Jess Higgins Kelley MNT (Author), Kelly Turner (Foreword)

The Biology of Cancer, 2nd Edition
by Robert A. Weinberg (Author)

The Cancer Revolution: A Groundbreaking Program to Reverse and Prevent Cancer
by Leigh Erin Connealy (Author)

Radical Remission: Surviving Cancer Against All Odds
by Kelly A. Turner PhD (Author)

Best Science Podcasts 2018

We have hand picked the best science podcasts for 2018. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Dying Well
Is there a way to talk about death candidly, without fear ... and even with humor? How can we best prepare for it with those we love? This hour, TED speakers explore the beauty of life ... and death. Guests include lawyer Jason Rosenthal, humorist Emily Levine, banker and travel blogger Michelle Knox, mortician Caitlin Doughty, and entrepreneur Lux Narayan.
Now Playing: Science for the People

#492 Flint Water Crisis
This week we dig into the Flint water crisis: what happened, how it got so bad, what turned the tide, what's still left to do, and the mix of science, politics, and activism that are still needed to finish pulling Flint out of the crisis. We spend the hour with Dr Mona Hanna-Attisha, a physician, scientist, activist, the founder and director of the Pediatric Public Health Initiative, and author of the book "What the Eyes Don't See: A Story of Crisis, Resistance, and Hope in an American City".