Researchers from Harvard Medical School and the University of California, Davis, blocked the progression of cancer growth caused by environmental carcinogens and food contaminants by resolving an eicosanoid/cytokine storm triggered by cell debris.
The research, from the laboratories of physician-researcher Dipak Panigrahy of Harvard Medical School and UC Davis distinguished professor Bruce Hammock, is published in the current edition of the Proceedings of the National Academy of Sciences.
“We advanced the hypothesis that cell debris from chemotherapy, resection of tumors and even immunotherapy can make these therapies a double-edged sword stimulating cancer growth and metastasis while treating it,” said Hammock, who holds a joint appointment in the UC Davis Department of Entomology and Nematology and the UC Davis Comprehensive Cancer Center.
In their paper, “Resolution of Eicosanoid/Cytokine Storm Prevents Carcinogen and Inflammation-Initiated Hepatocellular Cancer Progression,” the scientists covered the potent environmental carcinogen and food contaminant aflatoxin. Aflatoxins are toxins produced by certain fungi that are found in such agricultural crops as corn, peanuts, cottonseed, and nuts.
“Not only is this fungal metabolite genotoxic but it is also a tumor promoter,” said Hammock, defining a genotoxic agent as “a chemical that damages cellular DNA, resulting in mutations or cancer.”
Lead authors Anna Fishbein of Harvard University, a recently enrolled medical student in the Georgetown University School of Medicine, and Weicang Wang, a postdoctoral scholar in the Hammock lab, said aflatoxin exerts some of its cancer-promoting effects by generating cell debris which activate a pathway leading to eicosanoid and cytokine storms. These two classes of natural chemical mediators, they explained, control many of our defenses against pathogens, but when out of control, these storms lead to growth and metastasis of liver cancer.
“We demonstrated that debris generated by aflatoxin B1accelerates tumor dormancy escape in liver cancer models by stimulating a macrophage-derived eicosanoid and cytokine storm of pro-inflammatory mediators,” said Fishbein. “Thus, targeting a single inflammatory mediator or eicosanoid pathway is unlikely to prevent carcinogen-induced tumor progression.”
The researchers showed that the inhibition of the soluble epoxide hydrolase (sEH) pathway or the combined inhibition sEH and cyclooxygenase-2 (COX-2) pathways prevented the carcinogen debris-induced storm of both cytokines and lipid mediators by macrophages--specialized detect-and-destroy cells.
In animal models, the dual COX-2/sEH inhibitor PTUPB prevented the onset of debris-stimulated liver cancer. The dual inhibition of COX-2/sEH pathways may be “a novel approach” to control cancer of the liver, the researchers said.
“We also showed that carcinogen-generated debris stimulates an endoplasmic reticulum (ER) stress response which may promote HCC progression. Importantly, PTUPB prevents the ER stress response,” Wang added. “We created a novel model of debris-stimulated liver cancer designed to study new strategies for the prevention and treatment of carcinogen-induced cancers with tremendous potential to translate to the clinic.”
From a nutritional standpoint, aflatoxin is a common food contaminant, Wang said. “But good agricultural practice and post-harvest technology keep the levels very low. However, in much of the world, aflatoxin levels are so high that many crops are discarded. In other cases, these contaminated grain and nut crops enter the human food chain, where they cause acute toxicity, severe anemia and of course later lead to cancer.”
UC Davis co-author and nutritional scientist Yuxin Wang (who is the wife of Weicang Wang) said that “finding a way to modulate the events that lead to the eicosanoid storm would have a major effect on children's health in many developing countries.”
Fishbein and Allison Gartung of the Panigrahy lab not only used the soluble epoxide hydrolase inhibitors from the Hammock lab but also used some prototype drugs synthesized by chemist Sung Hee Hwang of the UC Davis School of Veterinary Medicine “which proved to be even better,” Hammock said.
“These compounds are a synthetic combination of cyclooxygenase inhibitors like celebrex with epoxide hydrolase inhibitors,” Hammock said. “Since epoxide hydrolase inhibitors stabilize the endoplasmic reticulium stress response and transcriptionally down regulate inflammatory cyclooxygenase we expected them to synergize with cyclooxygenase inhibitors. We were surprised and pleased with the dramatic interaction of these inhibitors when combined in the same molecule in reducing the cytokine and eicosanoid production by in response to cell debris.”
“The observations from Harvard show that by inhibiting soluble epoxide hydrolase, we can block the activation of these inflammatory cascades leading to tumor promotion, growth and metastasis,” Hammock said. “We have a compound in human clinical trials that inhibits sEH, which should be clinically available in a few years. In addition. we have found natural inhibitors of the epoxide hydrolase in a variety of plants, including crop plants. This may allow us to reduce the cancer risk and block the gastrointestional erosion and bleeding caused by dietary aflatoxin using natural means.”
Other members of the 15-member team are UC Davis researchers Jun Yang, Yuxin Wang and Sung Hee Hwang; Harvard researchers Haixia Yang, Victoria Hallisey, Jianjun Deng, Sanne Verheul, Allison Gartung, Diane Bielenberg and Mark Kiernan (now of Bristol-Myers Squibb); and Sui Huang, Institute for Systems Biology, Seattle. Hammock and Panigrahy are the corresponding authors.
The research drew strong financial support as the Panigrahy's laboratory is generously supported by the Credit Unions Kids at Heart Team, the CJ Buckley Pediatric Brain Tumor Fund, and the Joe Andruzzi Foundation; and Hammock's UC Davis grants from the National Institute of Environmental Health (NIEHS) Superfund Research Program, and the NIEHS RIVER Award (Revolutionizing Innovative, Visionary, Environmental Health Research).
Hammock, a member of the UC Davis faculty since 1980, has directed the UC Davis Superfund Research Program for nearly four decades. It supports scores of pre- and postdoctoral scholars in interdisciplinary research in five different colleges and graduate groups on campus. Last year Hammock received a $6 million, eight-year “Outstanding Investigator” federal grant for his innovative and visionary environmental health research: The award is part of the Revolutionizing Innovative, Visionary Environmental Health Research (RIVER) Program of NIEHS.
“Toxic environmental carcinogens promote cancer via genotoxic and nongenotoxic pathways, but nongenetic mechanisms remain poorly characterized. Carcinogen-induced apoptosis may trigger escape from dormancy of microtumors by interfering with inflammation resolution and triggering an endoplasmic reticulum (ER) stress response. While eicosanoid and cytokine storms are well-characterized in infection and inflammation, they are poorly characterized in cancer. Here, we demonstrate that carcinogens, such as aflatoxin B1 (AFB1), induce apoptotic cell death and the resulting cell debris stimulates hepatocellular carcinoma (HCC) tumor growth via an ‘eicosanoid and cytokine storm.' AFB1-generated debris up-regulates cyclooxygenase-2 (COX-2), soluble epoxide hydrolase (sEH), ER stress-response genes including BiP, CHOP, and PDI in macrophages. Thus, selective cytokine or eicosanoid blockade is unlikely to prevent carcinogen-induced cancer progression. Pharmacological abrogation of both the COX-2 and sEH pathways by PTUPB prevented the debris-stimulated eicosanoid and cyto- kine storm, down-regulated ER stress genes, and promoted macrophage phagocytosis of debris, resulting in suppression of HCC tumor growth. Thus, inflammation resolution via dual COX-2/sEH inhibition is an approach to prevent carcinogen-induced cancer.”
As of July 8, the commentary, “Inflammation Resolution: a Dual-Pronged Approach to Averting Cytokine Storms in COVID-19?”—the work of a nine-member team of Harvard University and UC Davis researchers—has been downloaded 11,444 times since its publication May 8, 2020. It is online at https://rdcu.be/b33IN.
In comparison, the most downloaded publication in CMR in 2019 received 5,712, statistics show.
Editor-in-Chief and Professor Kenneth Honn, who selected their commentary as the top paper of the month, said it drew more downloads the first week of publication than any other in the journal's history. The work is based on more than 40 years of eicosanoid research from the Hammock lab and more than 40 years of eicosanoid research from the Charles Serhan lab at Harvard Medical School.
“COVID-19 results in excessive inflammation and a cytokine storm caused by the human body's reaction to the SARS-CoV-2 virus,” said lead author Dipak Panigrahy, a Harvard University physician and researcher who collaborates with the Hammock laboratory.
“Controlling the body's inflammatory response to COVID-19 will likely be as important as anti-viral therapies or a vaccine,” Panigraphy said. “Stimulation of inflammation resolutions via pro-resolution lipid mediators that are currently in clinical trials for other inflammatory diseases is a novel approach to turning off the inflammation and preventing the cytokine storm caused by COVID-19.”
The drug is an inhibitor to the soluble epoxide hydrolase (sEH) enzyme, a key regulatory enzyme involved in the metabolism of fatty acids.
Panigraphy and Hammock said they are receiving “tons of calls, media requests and emails” from all over the world, including Norway, Japan, United Kingdom, Germany, France, Mexico and Belgium.
Pioneering research from the Panigrahy and Hammock labs shows that cell debris from surgery, chemotherapy, toxin exposure and other causes lead to production of high levels of pro-inflammatory mediators commonly called cytokines as well as eicosanoids.
“A rapid immune response is critical to controlling this virus,” Panigrahy emphasized.
“We believe it holds promise to combat the inflammation involved with this disease,” said co-author Hammock, a UC Davis distinguished professor who holds a joint appointment with the Department of Entomology and Nematology and the UC Davis Comprehensive Cancer Center. “It hit me in March that what we really need to do is not so much block cytokines as to move upstream to modulate them and resolve them rather than block inflammation.”
“We can increase the concentration of natural pro-resolving mediators termed EETs which act on a biological system to produce other pro-resolution mediators which modulate inflammation and actively resolve the process,” explained Hammock, who founded the Davis-based company EicOsis Human Health LLC, to bring the inhibitor to human clinical trials, which are underway in Texas.
The co-authors include two physician-researchers: Patricia Sime of the Division of Pulmonary and Critical Care Medicine, Virginia Commonwealth University, Richmond, and Irene Cortés-Puch of the Division of Pulmonary, Critical Care and Sleep Medicine, UC Davis Medical Center, and an EicOsis project scientist.
“It is this resolution of inflammation and the subsequent repair that is critical to restore patient health,” said Serhan, whose studies with collaborator Sime show that immune resolution and repair are active processes in the lungs and other tissues. What drives the process, Serhan said, is the production of specific pro-resolving agents (SPMs).
Other co-authors of the paper are Molly Gilligan and Allison Gartung of the Panigrahy lab; Sui Huang of the Institute for Systems Biology, Seattle; and Richard Phipps, independent scholar, Richmond, Va.
National Institutes of Health (NIH) grants, including a National Institute of Environmental Health Science (River Award) to Hammock, helped fund the research. The Panigrahy laboratory is generously supported by the Credit Unions Kids at Heart Team; the C.J. Buckley Pediatric Brain Tumor Fund; and the Joe Andruzzi Foundation.
Dr. Panigrahy is an assistant professor of pathology, Beth Israel Deaconess Medical Center, Harvard Medical School.
His topic is "Pro-Resolution Lipid Mediators in the Resolution of Cancer," said Hammock, who holds a joint appointment with the UC Davis Department of Entomology and Nematology and the UC Davis Comprehensive Cancer Center.
The abstract: "For decades, cancer therapy has focused on killing cancer cells, from broad cytotoxic therapy to the inhibition of specific molecular pathways. However, cytotoxic cancer therapy may inherently be a double-edged sword as apoptotic tumor cells ('debris') may stimulate inflammation and tumor growth via a pro-inflammatory ‘cytokine storm'. Environmental carcinogens (e.g. Aflatoxin B1) can also generate debris which may stimulate inflammation and tumor dormancy escape. This is clinically relevant as 30-90% of humans harbor dormant tumors."
"To stimulate the natural debris-clearing process which would eliminate this source of tumor stimulation, we utilized endogenous specialized pro-resolving mediators (SPMs), specifically maresins, which are biosynthesized by human macrophages from endogenous docosahexaenoic acid. Additionally, novel COX-2/sEH inhibitors (e.g. PTUPB) can stimulate inflammation resolution more potently than either COX-2 or sEH inhibition alone by stabilizing epoxy-eicosanoids, promoting the formation of pro-resolving mediators such as lipoxins, and activating anti- inflammatory cytokine programs. In dramatic contrast to conventional anti-inflammatories, pro-resolving lipid mediators clear debris and counter-regulate a series of pro-inflammatory cytokines. We demonstrate that the resolution of inflammation represents a novel modality in cancer treatment by enhancing endogenous clearance of tumor cell debris and counter- regulating pro-tumorigenic cytokines."
Earlier this year, a collaborative research paper authored by Hammock, Panigrahy and colleagues won the Editor's Pick of the Journal of Investigation for the month of July. The paper, “Preoperative Stimulation of Resolution and Inflammation Blockade Eradicates Micrometastases,” relates how blocking inflammation and/or activating the resolution of inflamation before surgery can eradicate small tumors and promote long-term survival in experimental cancer modes. (See news story.)
Dipak was accepted into medical school at Boston University at age 17. He trained in surgery with Dr. Roger Jenkins, who performed the first liver transplant in New England. Over the past decade, Dr. Panigrahy led angiogenesis and cancer animal modeling in the Judah Folkman laboratory. He joined the Beth Israel Deaconess Medical Center in 2013, and in 2014 was appointed assistant professor of pathology and currently has a laboratory in the Center for Vascular Biology Research.
For more information on the seminar, contact Hammock Lab account manager Gregory Zebouni at firstname.lastname@example.org or (530) 752-8465.
Cancer research published by a team of scientists, including the Bruce Hammock laboratory, University of California, Davis, has been named the Journal of Clinical Investigation's Editor's Pick for the month of July.
Scientists from UC Davis and Harvard Medical School co-authored the paper on how blocking inflammation and/or activating the resolution of inflammation before surgery or chemotherapy can eradicate small tumors and promote long-term survival in experimental animal cancer models.
The paper, “Preoperative Stimulation of Resolution and Inflammation Blockade Eradicates Micrometastases,” available online beginning June 17, combines the expertise of Professor Bruce Hammock and researcher Jun Yang of UC Davis with that of the Harvard Medical School team led by Dipak Panigrahy and Allison Gartung; Professor Vikas Sukhatme from Emory University School of Medicine, Atlanta; and Professor Charles Serhan from Brigham and Women's Hospital/Harvard Medical School.
“During chemotherapy or surgery, dying cancer cells can trigger inflammation and the growth of microscopic cancerous cells,” said Hammock, a distinguished professor who holds a joint appointment with the UC Davis Department of Entomology and Nematology and the UC Davis Comprehensive Cancer Center.
“We found that preoperative, but not postoperative, administration of the nonsteroidal anti-inflammatory drug ketorolac and/or resolvins, a family of specialized pro-resolving autacoid mediators, eliminated micrometastases in multiple tumor-resection models, resulting in long-term survival,” Gartung said. “Moreover, we found that ketorolac and resolvins exhibited synergistic anti-tumor activity and prevented surgery or chemotherapy-induced tumor dormancy escape in our animal models.”
Serhan explained that “Ketorolac unleashed anti-cancer T-cell immunity that was augmented by immune checkpoint blockade, negated by adjuvant chemotherapy, and dependent on inhibition of the COX-1/thromboxane A2 (TXA2) pathway. Pre-operative stimulation of inflammation resolution via resolvins (RvD2, RvD3, and RvD4) inhibited metastases and induced T cell responses.”
“Collectively, our findings suggest a paradigm shift in clinical approaches to resectable cancers," said Sukhatme. "Simultaneously blocking the ensuing pro-inflammatory response and activating endogenous resolution programs before surgery may eliminate micrometastases and reduce tumor recurrence."
This novel approach of blocking inflammation and/or accelerating the resolution of inflammation before a surgical procedure also holds promise for patients who do not have cancer. “More than 30 percent of healthy individuals harbor microscopic cancers," Panigraphy said. "Non-cancer surgery and anesthesia may promote the growth of existing micro-tumors."
- Dipak Panigrahy, Allison Gartung, Haixia Yang, Molly M. Gilligan, Megan L. Sulciner, Jaimie Chang, Julia Piwowarski, Anna Fishbein, and DulceSoler-Ferran, all with the Cancer Center, Beth Israel Deaconess Medical Center (BIDMC), Harvard Medical School (HMS);
- Charles N. Serhan from the Center for Experimental Therapeutics and Reperfusion Injury and Department of Anesthesiology, Perioperative and Pain Medicine at Brigham and Women's Hospital, HMS;
- Vikas P. Sukhatme from the Department of Medicine and Center for Affordable Medical Innovation at Emory University School of Medicine;
- Jun Yang and Bruce D. Hammock from the Department of Entomology and Nematology and UC Davis Comprehensive Cancer Center at University of California, Davis;
- Swati S. Bhasin and Manoj Bhasin from the Division of Interdisciplinary Medicine and Biotechnology, Department of Medicine, at BIDMC, HMS;
- Diane R. Bielenberg, Birgitta A. Schmidt and Steven J. Staffa from the Vascular Biology Program, Department of Pathology, and Department of Anesthesiology, Critical Care and Pain Medicine at Boston Children's Hospital (BCH), HMS;
- Matthew A. Sparks from the Division of Nephrology, Department of Medicine at Duke University and Durham VA Medical Centers;
- Vidula Sukhatme from GlobalCures Inc.;
- Mark W. Kieran from Division of Pediatric Oncology at Dana-Farber Cancer Center Institute and Department of Pediatric Hematology/Oncology at BCH, HMS; and Sui Huang from the Institute of Systems Biology.
The researchers said the project drew generous support from the National Cancer Institute (Panigrahy and Serhan), Beth Israel Deaconess Medical Center, the Credit Unions Kids at Heart Team (Panigrahy), C.J. Buckley Pediatric Brain Tumor Fund (Kieran), the Kamen Foundation (Kieran), the Joe Andruzzi Foundation (Kieran), National Institute of Environmental Health Science Superfund Research Program (Hammock); National Institute of Environmental Health Science (Hammock), Sheth family (Sukhatme), Stop and Shop Pediatric Brain Tumor Fund (Kieran), Molly's Magic Wand for Pediatric Brain Tumors (Kieran), the Markoff Foundation Art-In-Giving Foundation (Kieran), and Jared Branfman Sunflowers for Life (Kieran).
For 20 years, the Hammock lab has been researching an inhibitor to an enzyme, epoxide hydrolase, which regulates epoxy fatty acids, but the inhibitor drug was not involved in this particular research. However, many other publications and ongoing cancer research projects are. "My research led to the discovery that many regulatory molecules are controlled as much by degradation and biosynthesis," Hammock said. "The epoxy fatty acids control blood pressure, fibrosis, immunity, tissue growth, depression, pain and inflammation to name a few processes.”
Hammock and colleague Sarjeet Gill, now a distinguished professor at UC Riverside, discovered the target enzyme in mammals while they were postgraduate students at UC Berkeley.
The research, published in the current edition of the Proceedings of the National Academy of Sciences, shows that bioactive products from a major family of enzymes discovered in the UC Davis lab of Bruce Hammock, reduced the eye disease severity in an animal model with neovascular AMD. The compounds regulated inflammatory immune cells both locally—in the retina--and systemically.
Previous research has largely ignored the role of immune cells, “which likely are a major contributor in this pathologic process,” said corresponding author Kip Connor, a vision scientist at the Massachusetts Eye and Ear Infirmary and an assistant professor of ophthalmology at Harvard Medical School.
The chronic, progressive disease affects as many as 11 million Americans but that number is expected to double by 2020, said Connor, one of the nine international experts in lipid biology and AMD involved in the study. Globally, some 196 million are projected to get AMD by 2020. The risk of getting AMD increases from 2 percent for those ages 50-59, to nearly 30 percent for those over the age of 75, according to the Bright Focus Foundation, which helped fund the research.
Hammock, a distinguished professor who holds a joint appointment with the UC Davis Department of Entomology and Nematology and the UC Davis Comprehensive Cancer Center, expressed hope that the team “that Dr. Connor's laboratory will find a solution to this devastating human health problems."
The study, based in Connor's laboratory at Harvard, “shows how rapidly fundamental knowledge of physiology and regulatory biology can be translated to practical solutions for a major type of blindness,” Hammock said. “I was at Harvard several years ago and saw a poster outside a laboratory on AMD. This resulted in me meeting Eiichi Hasegawa, a doctorial fellow in the Connor lab, and through him, Kip, which has led to a long-term collaboration.”
“I also see the compounds that I made moving to human clinical trials with the hope of treating pain and inflammatory diseases such as AMD,” Hammock added.
“In patients with advanced AMD, abnormal blood vessels start to develop from underneath the light-sensing layer of the eye in a process known as choroidal neovascularization (CNV),” Connor explained. “Such cases, termed neovascular or “wet” AMD, account for 10 to 15 percent of AMD cases,develop abruptly, and rapidly lead to substantial vision loss.”
“Although we do not fully understand how and why AMD develops, identifying additional mechanisms that regulate abnormal blood vessel growth in the eye beyond what we currently know could open up a range of possibilities for new research and treatments for AMD,” Connor noted.
The team demonstrated that “specific bioactive products from the cytochrome P450 (CYP) pathway, a major family of enzymes, can influence CNV and vascular leakage by changing how immune cells are recruited to areas of disease and injury,” lead author Eiichi Hasegawa said. “Specifically, we isolated and characterized two key mediators of disease resolution generated from the CYP pathway: 17,18-epoxyeicosatetraenoic acid (EEQ) and 19,20-epoxydocosapentaenoic acid (EDP). “
“Our study offers new insights into bioactive lipid metabolites as regulators of systemic inflammatory immune cells and mediators in CNV resolution,” Connor said, noting that current treatments for AMD do not fully address the underlying causes of this disease. “Given the high prevalence and progressive nature of neovascular eye disease, the ability to stabilize bioactive lipids that mitigate or halt disease is of great and increasing therapeutic significance. It is our hope that emerging technologies and future studies will expand on our work and ultimately lead to safe, targeted, and cost-effective therapies that markedly improve visual outcomes and quality of life for patients suffering from these debilitating ocular diseases.”
Said co-author Kin Sing Stephen "Sing" Lee, who worked on the initial enzyme project as a postdoctoral researcher in the Hammock lab at UC Davis, and is now an assistant professor of pharmacology and toxicology at Michigan State University: “It was so exciting at UC Davis to be involved with basic research on inflammation but also see the compounds that I made moving to human clinical trials with the hope of treating pain and inflammatory diseases such as AMD. It was also a thrill to develop collaborations with scientists throughout the world like Eiichi Hasegawa and Kip Connor
In addition to Connor, Hammock, Lee and Hasegawa, co-authors of the publication, “Cytochrome P450 Monooxygenase Lipid Metabolites are Significant Second Messengers in the Resolution of Choroidal Neovascularization" include Saori Inafuku, Lama Mulki, M.D., Yoko Okunuki, M.D., Ph.D., Ryoji Yanai, M.D., Ph.D., Kaylee E. Smith, Clifford B. Kim, Garrett Klokman, Deeba Husain, M.D., and Joan W. Miller, M.D., of Massachusetts Eye and Ear/Harvard Medical School, as well as Diane R. Bielenberg, Ph.D., of Boston Children's Hospital/Harvard Medical School, Narender Puli, Ph.D., and John R. Falck, Ph.D., of the University of Texas Southwestern, Wolf-Hagen Schunck, Ph.D., of the Max Delbruch Center for Molecular Medicine in Germany, Matthew L. Edin, Ph.D., and Darryl Zeldin, M.D., of the National Institutes of Health's National Institute of Environmental Health Sciences (NIH/NIEHS).
The research was supported in part by the NIH NIEHS, Research to Prevent Blindness, Massachusetts Lion Eye Research Fund, BrightFocus Foundation, Harvard Department of Opthalmology and Massachusetts Eye and Ear Infirmary; the Japan Society for the Promotion of Science Postdoctoral Fellowships for Research Abroad; the Robert A. Welch Foundation, and by a scholar award and a medical student fellowship grant. (Follow the Connor lab on Twitter @ConnorLab and the Bruce Hammock lab on Facebook at https://www.facebook.com/hammocklab/)