The McArdle Laboratory mourns the loss of Günter Blobel, Nobel Prize-winning cell biologist who discovered and characterized how proteins are targeted within cells. Günter was one of the first trainees in McArdle's Cancer Biology Graduate Training Program to receive a Ph.D. (in 1967), training with Van Potter. He went on to doing ground-breaking research for five remarkable decades at the Rockefeller University in New York.
Read more about Dr. Blobel's amazing life and contributions to science here.
Paul Ahlquist and Masaki Nishikiori
Scientists at the Morgridge Institute for Research have discovered a promising new target to fight a class of viruses responsible for health threats such as Zika, polio, dengue, SARS and hepatitis C.
Masaki Nishikiori, a researcher in the Morgridge Institute virology group led by Paul Ahlquist, Morgridge investigator and professor of oncology and molecular virology at the University of Wisconsin–Madison, showed for the first time that, in replicating their genomes, viruses create pores inside parts of the cell that are normally walled off. This process of “punching through cellular walls” allows the virus to operate across different parts of the cell to activate and regulate its replication.
This could be big news in the quest to develop broad-spectrum antivirals, which are vaccines or drugs that target entire families of viruses. There are hundreds of viruses that threaten human health, but today the only way to combat them is by targeting each individual strain, rather than finding a common weakness.
The study, published on January 24 in the journal Science Advances, looks at a class known as positive-strand RNA viruses, which make up one-third of all known viruses (including the common cold). It appears that this pore-creating mechanism could be common across many or most members of this family of viruses.
“One exciting aspect of these results is that pores of different kinds in membranes are very important for many biological processes, and there are established drugs that interfere with them,” says Nishikiori. “We now recognize that this virus, and based on conserved features likely most viruses in this class, depend on similar types of pores to replicate. This is a target we know how to interfere with.”
Current pore-blocking drugs, also referred to as channel blockers, are used in treating high blood pressure, certain neurological or psychiatric disorders, including Alzheimer’s disease, and other maladies.
Nishikiori used biochemical and molecular genetic approaches to reveal the virus’ capacity to create and employ pores in a cell membrane. He used an advanced bromovirus model that allowed virus replication in yeast cells, which provided a highly controllable system to modify and assess both virus and host cell contributions.
In order to spread throughout the body, viruses hijack normal cell structures and functions to achieve their own ends. This class of virus, for example, always anchors its genome replication process to the membrane surfaces of cell sub-compartments or organelles (in this case, the endoplasmic reticulum). It had been understood this process occurred solely on one side of the membrane, outside of the organelle.
This study reveals the conventional view is incomplete. Nishikiori found that an enzyme called ERO1, which resides exclusively inside the organelle, on the opposite side of the membrane, is crucial to promoting the viral replication process. Reduce ERO1 and viral replication goes down, and vice versa, Nishikiori says.
The surprise was: How could an enzyme that was walled off from the virus by a solid membrane barrier activate viral growth? This was their first clue that something must be bridging the membrane. When combined with other insights, the team discovered that a key viral protein builds a pore or pipeline across the membrane, enabling ERO1 to affect viral replication on the other side.
Nishikiori previously found that the proteins creating these pores become strongly linked together by a particular kind of chemical bond, called a disulfide bond. However, these bonds can only be created in an oxidized environment. This explains at least one purpose behind the pores, Nishikiori says. They allow delivery of oxidizing power into the normally non-oxidized cytoplasm to form the disulfide bonds. “When the viral protein creates this pore, it allows oxidants generated by ERO1 to leach from the organelle interior into the cytoplasm and create a plume of oxidizing power,” he says.
Ahlquist speculates that the virus may use these strong linkages to keep the viral genome replication apparatus intact. Drawing on other recent findings, he says viral replication complexes inside cells are under significant pressure and at risk of breaking off before replication is complete. The strong bonds might be similar to the wire cage holding the cork in place on a champagne bottle, he says.
Basic research on the mechanisms of viral replication is essential to the larger quest to find broad-spectrum antivirals, one of the holy grails of virology, Ahlquist says.
“When you apply an over-the-counter anti-bacterial cream to a child’s scraped knee, it works even though you don’t know exactly which bacteria you’re fighting,” he says. “We don’t have anything like that for viruses; most of our antiviral vaccines and drugs are virus-specific. We need new approaches that target broadly conserved viral features to simultaneously inhibit many viruses.”
Paul Ahlquist is the John and Jeanne Rowe Chair of Virology and director of virology, Morgridge Institute for Research. Ahlquist also is a professor of oncology and molecular virology at the University of Wisconsin–Madison and a Howard Hughes Medical Institute (HHMI) investigator.
This article was originally published at news.wisc.edu/an-achilles-heel-discovered-in-viruses-could-fuel-new-antiviral-approaches/
Left: a papillomavirus. Right: dioxins, polycyclic aromatic hydrocarbons (AHRs), and polychlorinated biphenyls (PCBs). PAS proteins regulate a variety of downstream responses to these three molecules, some of which are toxic effects.
McArdle is pleased to announce that Paul Lambert and Chris Bradfield recently received Outstanding Investigator (R35) Awards from the National Institutes of Health. The R35 award is designed to support proven research investigators, allowing them the flexibility to pursue projects with more ambitious scopes and potential for innovation. Lambert and Bradfield’s recent grants were awarded by the National Cancer Institute (NCI) and the National Institute of Environmental Health Sciences (NIEHS), respectively.
Dr. Lambert is the director of the McArdle Laboratory, as well as the Howard M. Temin Professor and Chair of Oncology and the UW Carbone Cancer Center's Virology Program Leader. His grant was awarded in 2017 and provides 7 years of >$900,000 annual funding.
The research conducted under Dr. Lambert's grant will focus on the study of HPV-associated cancers, including anal, cervical, and head/neck cancers. High-risk strains of HPV are implicated in five percent of all human cancers, and HIV-infected persons have a significantly increased risk of developing these cancers. By using genetically engineered mouse (GEM) models, patient derived xenografts (PDXs), and a mouse papillomavirus model (MmuPV1) the Lambert lab will work to identify potential targets for the prevention and treatment of HPV-associated cancers.
Dr. Bradfield is Professor of Oncology, director of the Molecular and Environmental Toxicology Graduate Program, a member of the UW Carbone Cancer Center's Genetics Program, and served as interim director of the Wisconsin Institute for Discovery (WID) from 2015 to 2017. His grant, also awarded in 2017, provides 8 years of funding of >$800,000 annually.
Bradfield’s R35 will allow him to undertake a collaborative and transdisciplinary approach to investigating the role of the PAS family of sensor proteins and how they interact with environmental factors to cause disease. PAS proteins are involved in sensing a variety of key physiological conditions, including oxygen status, microbiome changes, and circadian time. By investigating the pathways by which key PAS proteins act, the Bradfield group hopes to generate better prevention and treatment solutions for a wide variety of environmentally influenced conditions including epithelial hyperplasia, immunosuppression, teratogenesis, and tumor promotion.
We are also pleased to announce that additional R35 grants were recently awarded to several McArdle alumni including John Coffin, an American Cancer Society Professor of Molecular Biology at Tufts University; Elsa Flores, a Senior Member of the Moffitt Cancer Center; and Thomas Kensler, Professor of Pharmacology and Chemical Biology at the University of Pittsburgh.
Congratulations to all McArdle R35 recipients, past and present!
Dr. Yongna Xing with lead author Cheng-Guo Wu
A new study by University of Wisconsin–Madison researchers identified the structural basis for how tightly bound protein complexes are broken apart to become inactivated. The structure explains why the complexes are less active in some cancers and neurodegenerative diseases, and offers a starting point to identify drug targets to reactivate it.
As we grow, our cells respond to tightly regulated cues that tell them to grow and divide until they need to develop into specialized tissues and organs. Most adult cells are specialized, and they correctly respond to cues that tell them to stop growing. Cancers can develop when something goes awry with those cues.
One such “stop and specialize” cue is found with the protein complexes known as PP2A. There are approximately 100 known PP2A complexes, and together they are estimated to regulate nearly one-third of all cellular proteins. These complexes consist of a core that is inactive until it mixes and matches with one of several specificity proteins to form tightly bound, active PP2A complexes. Active PP2A uses those specificity partners to find its targets – typically pro-growth proteins – and inactivates them. PP2A is a critical cue, then, in keeping cell growth in check and maintaining normal neurological functions. Not surprisingly, it is mutated in many cancers and neurological disorders.
“We know a lot about how active PP2A complexes form and are identifying more and more of their targets in cells, but we know very little about how they are inactivated,” explains Yongna Xing, an associate professor of oncology with the UW Carbone Cancer Center and McArdle Laboratory for Cancer Research and the senior author of a new study published on Dec. 22, 2017 in Nature Communications. “It’s a very tightly held complex, it’s almost like a rock, but there has to be a way to break it up.”
Xing’s previous work showed that PP2A is inactive when a regulatory protein, a4, is attached. However, when active PP2A complexes were challenged with a4, they remained active, meaning there had to be another trigger that broke the complex apart.
In the new study, Xing and her colleagues identify that trigger as the protein TIPRL. When they challenged active PP2A complexes with a4 and TIPRL, the complexes broke apart. Next, they determined the three-dimensional structure of TIRPL with PP2A through a technique known as X-ray crystallography.
“The structure shows how TIPRL can attack active PP2A complexes even though it has a much lower affinity than the specificity subunits do for PP2A core,” Xing says. “With the structure we were able to identify how TIRPL can attack the complex, change its conformation and, together with a4, make it fall apart robustly. It was hard to picture how this process could happen without structural insights.”
If we think of PP2A as a power screwdriver, the findings make a lot of practical sense. The core protein is the motorized base, and the specificity proteins – the ones that mix and match to help PP2A find the right target – are the screw heads. When you want to switch from a Phillips-head to a flathead screwdriver, you don’t throw away the whole power screwdriver complex and buy a new one; rather you detach one screw head and attach another. Similarly, it is energy costly for a cell to degrade the entire PP2A complex, so TIPRL’s role is to detach the specificity protein and recycle PP2A core.
One of the more interesting findings from the structure was how flexible TIRPL is compared to the specificity subunits, prompting the researchers to ask how PP2A mutations commonly seen in cancer patients affect TIPRL binding. Using either normal or PP2A core containing these mutations, they measured how well TIPRL and the specificity subunits can bind to it. They found that the core mutations have almost no effect on TIPRL binding, but they drastically weaken the binding of specificity proteins. These mutations, then, likely cause a shift from active PP2A complexes to the disassembled and inactive form.
“In many diseases, including cancers and neurodegenerative diseases, PP2A in general is less active, often due to mutations,” Xing notes. “This structure helps explain how those mutations lead to downregulation of PP2A by shifting the balance toward TIPRL-induced complex dissociation.”
With the structure in hand, Xing expects to be able to better understand the cycle of PP2A activation and inactivation, and how it regulates cell growth.
“For example, active PP2A is known to inhibit K-ras, a protein that drives growth in many tumors and currently has no good clinical inhibitors,” Xing says. “If you can find a way to re-activate PP2A, it could be very important in treating those cancers.”
The study was supported by National Institutes of Health grant R01 GM096060-01.
Slideshow image on home page: Structure of the PP2A-TIPRL complex, including the PP2A scaffold subunit (green), the PP2A catalytic subunit (blue), and the TIPRL (magenta). From Wu et al., Nature Communications 2017 Dec 22; 8(2272).
This article was originally published at https://news.wisc.edu/breaking-up-protein-complexes-is-hard-to-do-but-new-uw-study-shows-how/
A sampling of the goods created by the Family Crafters
In Brillion, WI, an amazing family works throughout the year to create craft goods to sell at farmers’ markets, craft shows, and grocery stores. Together, they are the Family Crafters, using their time and talents to raise money for cancer research in a unique and creative way. The Family Crafters create a wide variety of items, ranging from hand towels and potholders to coasters and jewelry, and have generously chosen to donate all profits to McArdle. Some popular items such as their grocery bag holders and catch-all bags are staples, but their selection of offerings is constantly rotating as they continually incorporate new types of goods into their arsenal.
The Family Crafters was formed after several members of the family behind the group were diagnosed with cancer. Collectively, they decided that they wanted to do something to make an impact. For the past decade, the members have been creating goods to raise money for national cancer organizations. As their efforts grew, however, they decided they wanted to support cancer research more directly. The Family Crafters chose to begin donating to McArdle two years ago to make sure the money raised through their hard work and dedication reached the cause they cared about and stayed within Wisconsin.
The members of the Family Crafters have found that their local communities are extremely supportive of their efforts. In addition to appreciating the wonderful crafts they make, many of the people they encounter while selling their goods share stories about their own experiences with cancer, encouraging the group to continue their amazing work.
“When we’re selling the products and people as so appreciative of what we are doing, it makes it all worthwhile,” said a member of the Family Crafters. “We hear their stories, and they’re just grateful that we are out there doing what we do, and that we're doing it all non-profit to benefit cancer research.”
Wei Xu, right, with McArdle Director Paul Lambert and Ron and Ruth Niendorf. Mr. and Mrs. Niendorf were friends and neighbors of Marian Burgenske, and helped her establish the endowment for Dr. Xu's professorship.
McArdle is excited to announce that Wei Xu has been named the new Marian A. Messerschmidt Professor in Cancer Research. Dr. Xu, who has been a faculty member with McArdle since 2005, is also a member of the Carbone Cancer Center Genetics Program and the National Institutes of Health Cancer Biomarkers Study Section. The Messerschmidt endowed professorship was originally held by former McArdle director and Department of Oncology chair Norman Drinkwater, now the Associate Vice Chancellor for Research in the Biological Sciences.
Dr. Xu’s research focuses primarily on studying the transcriptional regulation of estrogen receptor signaling in breast cancer, as well as the epigenetic modifications associated with carcinogenesis. Recently, groundbreaking work from her lab studying how the CARM1 methyltransferase protein regulates cancer progression has been published in premier journals including Nature Cell Biology, Nature Communications, and Cancer Cell.
“Curing breast cancer is our mission,” said Dr. Xu of her lab’s work. “However, there are many different subtypes, so we need to know more about the molecular mechanisms for the initiation, metabolism, and metastasis of breast cancer so we can design more personalized treatments.”
The named professorship recognizes Dr. Xu’s dedication to cancer research and her past accomplishments, and provides her financial support to continue her investigation into breast cancer going forward. Proceeds from the endowment will be used both to support Dr. Xu’s salary and provide her lab with additional funding.
The donor of the endowment for Dr. Xu’s professorship, Marian Burgenske, was a lifelong resident of the Madison area. Born in 1906, she graduated from Wisconsin High School and attended the now-defunct Madison Business College. Shortly after graduating, Marian began working at the registrar’s office of Madison Area Technical College, a job she served in for over 45 years.
As she began working, Marian’s father gave her an ultimatum: she could continue living at home, but only if she was responsible with her money. For Marian, it was an easy choice. She decided to continue living with her parents, even after marrying her husband Rodney in 1930. This financial freedom allowed Marian to begin investing her income in stocks and bonds from a young age. She was an extremely organized and shrewd investor, never using a bookkeeper but rather meticulously tracking and recording all of her own investments.
Marian’s own experiences with cancer inspired her to donate the fruits of her hard work, thrift, and prudent investing to supporting cancer research. During her early life, she battled ovarian cancer, and several decades later was diagnosed with breast cancer. Her neighbor and close friend Ron Niendorf suggested that Marian fund an endowment, allowing the impact her donation to continue in perpetuity. She agreed, and the Marian A. Messerschmidt endowment was established in her maiden name, as per her wishes. The Marian A. and Rodney P. Burgenske Chair in Diabetes Research at UW-Madison, currently held by Dr. Vincent Cryns, as well as the Marian Messerschmidt Scholarship for judicial reporting at MATC were also established from her estate.
Dr. Roz Boutwell and Alex Law
On June 6, 2014, Dr. Roswell “Roz” Boutwell gave a talk on McArdle’s early history. Dr. Boutwell had joined McArdle in 1945, and was one of the core faculty members who helped transform McArdle into a leading cancer research institute. His talk highlighted his role along with the role of many of his colleagues during the early years of McArdle, and delved into some of the key discoveries which propelled McArdle’s research.
Dr. Boutwell passed away on August 25, 2017, at the age of 99. He was the last surviving member of McArdle’s early faculty core. Though the original women and men whose work spearheaded McArdle’s growth and development are no longer with us, their legacy persists thanks to their indelible contributions to the University of Wisconsin and basic cancer research.
Below is a reflection by McArdle graduate student Alexandra Law on Dr. Boutwell’s talk, originally published in July of 2014. A memorial to Dr. Boutwell can be read here.
Upon leaving a pleasant community talk by Dr. Roz Boutwell, a longtime Professor Emeritus of Oncology at the McArdle Laboratory for Cancer Research, I couldn’t help but think of a quote made popular by Sir Isaac Newton: “If I have seen further it is by standing on the shoulders of giants.” For Dr. Boutwell had just finished speaking of the early days of McArdle Laboratory and of the “Core” group of individuals involved who played key roles in establishing the first cancer research program at the University of Wisconsin; a program which had its humble beginnings 75 years ago in the year of 1939, and would grow to be recognized around the world as a leading center for basic cancer research.
What was particularly remarkable about this talk was 97-year-old Dr. Boutwell himself. Not only was he still quite energetic and incredibly sharp-minded but, as his age suggests, he was a part of this “Core” group of academics who had such high hopes and ambitions for basic cancer research at the University of Wisconsin. These scientists were staunchly dedicated to initiating and developing a strong cancer research program at a time when there was very little support and funding for it. Dr. Boutwell spent the majority of his talk focusing on this “Core” group of people with their remarkable achievements and contributions to cancer research.
Dr. Boutwell identified the years of 1939-1948, the first years of McArdle Laboratory, as key for the program. He stressed that the work of this “Core” group during this time was instrumental to McArdle’s success many years later. Dr. Boutwell stated that to him, the word “Core” meant “heart.” He was undoubtedly referring to the incredible persistence and determination that this “Core” group of academics had in building a strong cancer research program in Wisconsin and in the US.
Introducing the people that made up the “Core”, Dr. Boutwell started with Dr. Harold P. Rusch. Dr. Rusch, who obtained his college and medical degree from the University of Wisconsin (UW), is easily considered the most influential member of the “Core” because he was the first Director of the McArdle Laboratory and the first key motivator in establishing a cancer research program in Wisconsin. With the help of funds bequeathed by Michael W. McArdle, an attorney and entrepreneur from Door County, Wisconsin, who before his passing from cancer in 1935, requested that his funds be directed towards cancer research in Wisconsin, Dr. Rusch spearheaded the building of a facility on the UW campus to house laboratories solely devoted to cancer research. Dr. Boutwell describes Dr. Rusch as being very optimistic, energetic, easily approachable, and willing to talk to anybody. Dr. Rusch was a leader and having received training in Physiology, became very interested in cancer and implementing the first cancer research on campus. He believed that the field of Biochemistry could reveal many of the unknowns of cancer and hoped to look inside a cell to visualize the mechanisms involved. Dr. Rusch, being the first Director of McArdle, was responsible for successfully recruiting many strong scholars to serve as faculty in the program. These early faculty members proved to be outstanding scholars in their own right and thus comprised the rest of the “Core” group that would propel McArdle forward in cancer research.
Dr. Rusch’s first faculty recruit was Dr. Van R. Potter. Dr. Potter received his undergraduate degree from South Dakota State College and received his Ph.D. at UW. In his book “Something Attempted, Something Done,” Dr. Rusch describes Dr. Potter’s early interest in Enzymology; specifically, comparing enzyme activities in normal and cancerous tissues. Dr. Boutwell emphasized that it was Drs. Rusch and Potter that made up the “heart” of the “Core”. Though they were both studying separate problems, they communicated often and filled the other in on what was and was not working in the lab. They quickly understood that, although they were the first and, for a short time, the only project leaders present in the new program, that by working together they could establish a foundation for cancer research appealing to new faculty recruits who shared their goals.
The next two recruits of the fledgling program were James and Elizabeth Miller who arrived in the program in 1943 and 1945 respectively after completing their graduate training at UW. James, or “Jim” as he was known by his colleagues, was brought in for his expertise in chemical carcinogenesis and Elizabeth, or “Bette” as she was more affectionately known in the department, was sought after for her training in nutritional carcinogenesis. While at McArdle, both published seminal work that Dr. Rusch describes as “classic in its field”. Dr. Rusch states that “[James and Elizabeth] have added more to our basic understanding about how chemical carcinogens induce cancer than anyone else in the world.” Among their many contributions, one of their greatest was recognizing that most chemical carcinogens require metabolic activation to become electrophilic reactants. It is these chemically active compounds that can induce mutations and thereby be carcinogenic. Dr. Boutwell emphasized that though each was a highly proficient scientist in his and her own right, and that while in the department they each had their own studies and lab personnel, the Millers operated often as a team. He stressed that they complemented each other, they were each in tune to the other’s work, and they often relied on the other’s professional expertise. Dr. Boutwell spoke highly of them and considered them to be close colleagues and friends. It was with sorrow that he spoke of their passing from cancer.
Lastly, Dr. Boutwell spoke of himself and his arrival at McArdle in 1945. He received his graduate training in the Biochemistry Department at UW. At that time, Dr. Rusch had been seeking someone with knowledge in nutrition to provide expertise on the effects of diet on cancer formation. Since Dr. Boutwell had developed a strong background in nutrition as a graduate student, Dr. Rusch considered him to be a suitable candidate to provide this expertise. In addition to his work on nutrition and carcinogenesis, Dr. Boutwell made great advances in the field of tumor promotion. He found that some compounds that initiate cancers may not be sufficient to promote tumors, but that these compounds in combination with a tumor promoter can cause cancers. Dr. Boutwell mentioned that it was in these early days that they began to appreciate the power of hormones in carcinogenesis and early questions of the role of hormones in prostate cancer were formed at this time.
In addition to speaking of his previous research, Dr. Boutwell went into detail about the strong relationships he had developed with other faculty members of the program. He told several entertaining stories of those early days, one of which involved him participating in a weekly poker club that these colleagues used to be a part of. While telling these stories, Dr. Boutwell briefly spoke of his personal relationship with his wife, Louise, or “Lou”. In hearing Dr. Boutwell’s stories, it was clear that he treasured the personal and professional relationships he had developed with his family and his colleagues. Accordingly, members of the department have considered Dr. Boutwell to be a particularly special colleague in that whenever a fellow colleague was in need of assistance, he was consistently available to help. His trustworthiness, reliability, and dependence were important contributions that Dr. Boutwell made to the program. Hearing of how Dr. Boutwell is remembered by his colleagues helped me realize that McArdle was built not only by its research but also by its individuals such as Dr. Boutwell who made significant contributions, many of which cannot only be measured by publication success, to the program.
Dr. Boutwell concluded his talk recognizing that an hour was simply not enough to recognize every person involved in the early days who contributed to the success of McArdle and that there were many names that he did not have a chance to introduce. Yet he emphasized that the roles of Drs. Rusch, Potter, James Miller, Elizabeth Miller, and himself were crucial to establishing the program that remains in existence today, 75 years later. Sadly, the sorrow that Dr. Boutwell felt about the Millers also punctuated his talk since of the “Core” members described, he alone survives. Yet he emphasized how grateful he was to have been able to spend much of his career with such remarkable colleagues and was pleased and excited to be able to speak to us at length about them and their contributions to the cancer research program at UW and to the cancer research field. It was upon hearing him that I was reminded of the quote about “… standing on the shoulders of giants.” It was quite a pleasure to be a member of this audience and hear of the magnanimous efforts made by historically important members of McArdle Laboratory to create a strong research program that would provide the highest training for graduate students such as myself. Experiences such as this one help me and other students appreciate being given the opportunity to be a part of this excellent program.
Feature image on home page: Dr. Boutwell (center, in beige jacket) with McArdle faculty after his June 6, 2014 talk.
Prior to 2003, there was almost no multiple myeloma (MM) research ongoing at UW-Madison. However, the Trillium Fund was established that year by several generous patients to support myeloma research at the UW Carbone Cancer Center. In 2004, Dr. Natalie Callander was recruited to the UW-Madison and the Multiple Myeloma Working Group was established. Now, the MM working group is vibrant with physician scientists, pathologists, and basic scientists working together to improve our understanding of the disease and to develop new treatment approaches. Members receive multi-investigator grants from National Cancer Institute and other agencies to support research activities. Since the formation of the MM working group, the members of the group have held many seminar presentations for patients, their family members and friends over the years with topics ranging from basic discoveries to clinical trials to new therapeutic options.
On November 9 this year, the MM working group held “UWCCC Multiple Myeloma Update” seminars for over 200 patient participants with topics including clinical trials update (Dr. Callander), mind-body influences on myeloma (Dr. Constanzo), immunotherapy (Dr. Hall), predicting drug responses (Dr. Miyamoto), anti-myeloma immunity (Dr. Asimakopoulos), minimal residual disease (Dr. Leith), synstatin drugs (Dr. Rapraeger), microbiome influence (Dr. D’Angelo), and novel cell therapies (Dr. Hematti). This morning seminar session was followed by lunch and tours of the bone marrow transplantation clinic (Dr. Hematti) and WIMR labs (Drs. Asimakopoulos and Miyamoto). Many of the participants took the opportunity to take these tours and asked questions regarding basic and clinical research and how their myeloma biopsies and samples are utilized to learn the biology of the disease and to develop new therapeutics. Overall, this public event was highly successful and the MM group is looking forward to continuing to host future events to inform the patients on ongoing multiple myeloma research at UW-Madison and to provide up-to-date information on MM therapy.
-Dr. Shigeki Miyamoto
Feature image on home page: McArdle facuty member Shigeki Miyamoto presents at November 9th's event.
Dr. Xu and her lab group. From left to right: Kristine Donahue, lead author Fabao Liu, author Yidan Wang, Justine Coburn, Carlos Coriano, senior author Wei Xu, Steve Chan, Eui-Jun Kim, and Dominic Dharam. Contributing scientists not pictured: Fengfei Ma, Yuyuan Wang, Ling Hao, Hao Zeng, Chenxi Jia, Peng Liu, Irene M. Ong, Baobin Li, Guojun Chen, Jiaoyang Jiang, Shaoqin Gong, and Lingjun Li.
As cells with a propensity for cancer break down food for energy, they reach a fork in the road: They can either continue energy production as healthy cells, or shift to the energy production profile of cancer cells. In a new study published on Oct. 23, 2017 in the journal Nature Cell Biology, University of Wisconsin–Madison researchers map out the molecular events that direct cells’ energy metabolism down the cancerous path.
The findings could lead to ways to interrupt the process.
“Cancer cells often change their nutrient utilization and energy production, so many efforts are being made to develop drug inhibitors of cancer cell metabolism to starve them,” says senior author Wei Xu, the Marian A. Messerschmidt Professor in Cancer Research at the UW Carbone Cancer Center and McArdle Laboratory for Cancer Research. “We have found that inhibiting a chemical modification of a cancer-associated metabolism protein is enough to inhibit the aggressive nature of cancer cells.”
Cancer biologists have identified nearly a dozen “hallmarks of cancer,” or large-scale changes that send a precancerous cell over the tipping point to become a cancerous one. One hallmark of cancer is the loss of properly regulated energy metabolism, a process referred to as the “Warburg effect” after the Nobel laureate, Otto Warburg, who identified it.
Other hallmarks of cancer include continuous activation of growth pathways, the inability to respond to signals that put the brakes on cell growth, and a gain of invasion and spread to distant organs.
“My lab studies a protein, CARM1, which is associated with worse outcomes in breast cancer patients, though it has also been found expressed in many other cancer types,” Xu says. “CARM1 chemically modifies its target proteins to alter their function, and in doing so directly leads to the activation of several hallmarks of cancer.”
In the study, Xu and her colleagues found that CARM1 protein modifies a cell metabolism protein, PKM2, and changes its function. This drives the Warburg effect, activating a hallmark of cancer. Nearly a decade ago, researchers found that PKM2 was expressed at high levels in cancer cells, but how these levels translated to more aggressive cancers was not known.
So, Xu and colleagues performed a protein interaction assay in a breast cancer cell line and found that CARM1 interacts with and chemically modifies PKM2.
They also assessed whether CARM1-directed modifications of PKM2 might be responsible for leading cells down a cancerous pathway. By engineering cells to express “normal” PKM2 or a mutated form that was not modifiable, the researchers learned that PKM2 appears to be the deciding factor in picking the direction cell metabolism takes at that fork in the road. The CARM1-modified PKM2 shifted cells toward the cancer cell metabolism path while cells with PKM2 that could not be modified took the metabolic path associated with noncancerous cells.
With a clearer picture of how cancer cells shift their metabolism, the researchers next used a mouse model of breast cancer and a competitor drug that prevents CARM1 from effectively modifying PKM2 to test what would happen.
“When we block PKM2 modification by CARM1, the metabolic energy balance in cancer cells is reversed, and we see a decrease of cell growth and cell spreading potential,” Xu says. “This study, then, identifies another therapeutic target to help reverse several hallmarks of cancer.”
In addition to targeting PKM2 modification by CARM1, Xu’s lab is investigating how CARM1 recognizes all of its many target proteins, with the goal of disrupting those protein modifications from driving aggressive cancers.
Xu’s research colleagues include postdoctoral fellow and lead author Fabao Liu, and co-investigators Shaoqin Sarah Gong and Lingjun Li. Gong’s group engineered the unique nanoparticle that allowed for the delivery of the PKM2 competitor, and Li’s group identified where the PKM2 protein was modified by CARM1.
The work was supported by grants NCI R01 CA213293 and R21 CA196653, as well as the UW Carbone Cancer Center core support grant, NIH/NCIP30CA014520.
Slideshow image on home page: Inhibiting PKM2 methylation increases Ca2+ uptake and mitochondrial membrane potential, both important factors for oxidative phosphorylation. The top row images show the co-localization of mitochondrial tracker and Rhod-2 (a Ca2+ indicator) in MCF7 PMK2-KO cells. The bottom row images show Rhod-2-labelled mitochondria in parental MCF7, PKM2-KO, PKM2WT/shPKM1 and PKM2mut/shPKM1 cells. From Liu et al., Nature Cell Biology 2017 Oct 23; 19(11): 1358–1370.
This article was originally published at https://www.med.wisc.edu/news-events/new-study-shows-how-cells-can-be-led-down-non-cancer-path/51459
Expression of both HPV oncogenes E6/E7 and estrogen (E2) alter host gene expression in the cervical stroma. The Venn diagrams and pie charts in this figure show the differential expression of genes in the stroma for E6/E7, E2, and E6/E7+E2 compared to WT mice. From Spurgeon et al., PNAS. 2017 Oct 9; 114(43): E9076-E9085.
Human papillomavirus (HPV) and the hormone estrogen are both linked to the development of cervical cancers, but how they work together has remained unclear. A new study by University of Wisconsin-Madison researchers shows how the combination of two factors influences the local cervical environment and drives the progression of cancer development.
HPV is a virus that infects epithelial cells of mucous membranes such as the vagina, anus or back of the throat. Over 150 strains of HPV are known, ranging from those that cause benign warts to the high-risk strains that cause the majority of all HPV-associated cancers. However, only some high-risk infections progress to cancers, and a better understanding of what factors drive cancer formation should lead to improved therapies.
“Before I started in the Lambert lab, former lab members had discovered that not only is estrogen important in HPV-associated cervical cancers in mice, it is estrogen signaling through the non-cancerous stromal cells, also called the microenvironment, that is important,” said lead author Dr. Megan Spurgeon, an assistant scientist in Dr. Paul Lambert’s lab. “At the same time, Dr. Paul Ahlquist’s lab was looking at human cervical cancer samples and found a role for estrogen signaling through the stroma.
Spurgeon and her research colleagues wanted to know if HPV infection caused the epithelial cells to send a signal that altered the microenvironment, and if the stromal cells in turn sent a signal to the HPV-infected cells that promoted their cancerous growth. So they took a more detailed look at the Lambert lab’s mouse model of cervical cancer. In these mice, high-risk HPV genes are expressed only in cervical epithelial cells; the mice only develop cervical cancer if they are given extra estrogen.
“This model allows us to determine the contribution of HPV alone, estrogen alone, or both together,” Spurgeon said. “And then we used a really precise laser-based dissection tool that allowed us to exactly capture epithelial tissue or stromal tissue and to ask how they each respond to the different factors.”
With the epithelial and stromal tissue precisely separated, the researchers measured changes in total gene expression of the different tissue compartments in response to HPV or estrogen. They compared HPV mice to non-HPV mice, and found hundreds of gene expression differences in the stromal cells.
“The high-risk HPV genes alone were able to reprogram or change gene expression in the nearby stroma, even though HPV genes are not present in the stroma,” Spurgeon said.
Next, they asked how estrogen affected stromal gene expression with or without HPV in the epithelium. They found that estrogen alone causes some changes, as expected. But in the HPV mice treated with estrogen, they found a different set of genes expressed in the stroma than with either factor alone. It was this subset of genes that helped them identify the potential factors involved in crosstalk between the HPV-infected epithelial cells and the estrogen-receptive microenvironment.
Using human cervical cancer cells, they further investigated a class of these genes, the pro-inflammatory chemokines, which are known to move between cells. They grew cells either by themselves or in co-culture with cervical stromal cells, and measured levels of the inflammatory chemokines, and found higher levels in the co-culture.
“The hypothesis now is that those inflammatory chemokines are secreted by the stroma and are feeding back on the epithelial cells or some other cells in the microenvironment to drive cancer development,” Spurgeon said. “The next step is to use our mouse model and genetically engineer it to knock down the chemokine receptors on different cell types or inhibit the chemokine signaling with drugs to see if they are directly contributing to cancer.”
While estrogens are not linked to other HPV-associated cancers, this study highlights how HPV influences the microenvironment to contribute to other cancers.
“The fact that HPV alone was able to reprogram the nearby stroma is an important finding, and suggests that HPV could be conditioning the microenvironment to respond to other factors in other HPV-associated cancers,” Spurgeon said.
The study was published online October 9 in the journal Proceedings of the National Academy of Sciences. It was funded in part by NIH grants CA022443 and P30 CA014520.
Spurgeon is supported by an NIH R50 Research Specialist award (CA211246), a category of new support grants for exceptional scientists who are pursuing research in an existing research program but are not faculty leads themselves. She is the first recipient of such an award at UW; read more about Spurgeon and her R50 award here. Study co-authors include UW Carbone Cancer Center members Lambert, director of the McArdle Laboratory for Cancer Research; Ahlquist, investigator at the Howard Hughes Medical Institute, the Morgridge Institute for Research and McArdle; Dr. David Beebe, director of the UW Microtechnology, Medicine and Biology Lab; and Dr. Avtar Roopra, associate professor of neuroscience.
Conflict of interest statement: Beebe holds equity in Bellbrook Labs LLC, Tasso Inc., Stacks to the Future LLC, Lynx Biosciences LLC, Onexio Biosystems LLC, and Salus Discovery LLC.
Slideshow image on home page: Lead author Megan Spurgeon and principle investigator Paul Lambert.
This article was originally published at https://www.med.wisc.edu/news-events/study-shows-hpv-works-across-cellular-borders-to-drive-cervical-cancer/51428