Bruce Hammock, UC Davis distinguished professor (Photo by Kathy Keatley Garvey)

(Embargo lifts at 1 p.m., June 17. See online paper)

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.

Panigrahy described cancer therapy "as a double-edged sword, as surgery and chemotherapy can induce an inflammatory/immunosuppressive injury response that promotes dormancy escape and tumor recurrence. We hypothesized that these events could be altered by early blockade of the inflammatory cascade and/or by accelerating the resolution of inflammation.”

The researchers, in studying new therapeutic approaches to overcome the tumor-promoting capability of surgery, utilized a well-established animal model in which tumor dormancy escape and the outgrowth of lung metastases is triggered by primary tumor resection.

“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."

Co-authors include:

• 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.