Breakthrough publication! Our recent paper in Nature Communications explains the novel structure-function mechanism by which cholesterol promotes colon cancer. From a functional perspective, Wnt factors organize to form specialized plasma membrane (PM) domains. Dysregulation of Wnt domain structure can promote oncogenic Wnt signaling. Here, we describe an intricate Wnt signaling-associated mechanism involving oncogenic truncated APC and the loss of PM cholesterol homeostasis, which alters the organization of Wnt signaling nanoassemblies (biomolecular condensates) and drives aberrant Wnt signaling and CRC tumorigenesis. These highly significant findings are relevant to the nascent field of “membrane therapy”.
Jennie P. Kim, a Nutritional Sciences major working on her Undergraduate Research Scholars Thesis in the Chapkin Lab (https://chapkinlab.tamu.edu) was recently awarded second place for her poster presentation in the Agricultural and Life Sciences category at the Texas A&M Student Research Week competition (https://srw.tamu.edu). Student Research Week is the largest student-run research symposium in the nation, spotlighting student research conducted at Texas A&M University. Currently, her research focuses on the effects of short-chain fatty acids (e.g., butyrate) on colonic organoid stem cell homeostasis and gene expression in high vs. normal glucose conditions. She plans to continue her involvement in undergraduate research in the Chapkin Lab and hopes to provide important contributions related to the expanding field of Precision Nutrition.
The Chapkin Lab is pleased to announce the award of a $6 million grant from Cancer Prevention and Research Institute of Texas – TREC funding to support research in “Gene – environment – lifestyle interactions in cancer”. Dr. Robert Chapkin to serve as Deputy Director of the grant, Dr. Kenneth Ramos to serve as Director. As part of this effort, we will establish a single-cell data science (SCDS) core at Texas A&M University in Bryan/College Station. The SCDS core will serve as a Texas A&M Shared Resource Facility. In terms of the complementary CPRIT grant and the SCDS core, Drs. James Cai and Yang Ni will serve as Director and co-Director, respectively.
Drs. Robert Chapkin, Gus Wright, James Cai, and Stephen Safe received a new NIH grant to perform a single cell multi-omic analysis of the colon tumor microenvironment to probe the mechanistic underpinnings of NR4A1-dependent modulation of T-cell exhaustion.
Preliminary data indicate that the compounds developed in the laboratory of Dr. Stephen Safe both kill tumors and rejuvenate the immune system, which becomes exhausted as it responds to cancer.
A team of Texas A&M University researchers has received a $2.3-millon grant from the National Institutes of Health to further explore a unique immunotherapy that could be the first of its kind to treat colon cancer and could hold the key to treating other forms of cancer as well.
The collaborative, four-year project will determine how to best utilize a new class of drugs developed in the laboratory of Dr. Stephen Safe, a Distinguished Professor in the Texas A&M School of Veterinary Medicine & Biomedical Sciences’ (VMBS) Department of Veterinary Physiology & Pharmacology. The project will also explore the effects of the new compounds on human and murine cancer cells.
Led by Safe, the team also includes VMBS researchers Gus Wright and James Cai, as well as College of Agriculture and Life Sciences researcher Robert Chapkin and Houston Methodist Hospital oncologist Maen Abdelrahim.
Safe’s compounds target two receptors—NR4A1 and NR4A2—that are normally responsible for helping humans and animals lower stress levels but are overexpressed in colon cancer and other solid tumors.
“In the case of solid tumors, these two receptors are bad; they regulate the growth of a cell, how it metastasizes, how it invades, and how it survives,” Safe said. “When we screened these receptors, we found out that our compounds that we’ve been working on over the years bind with high affinity (binding strongly). Binding can sometimes be bad, making the tumor worse, or binding can be good, by being an antagonist. In this case, the compounds are antagonists—they just wipe out the tumor.”
Not only does their preliminary data indicate that their compounds act as an immunotherapy and kill the tumor, but the compounds also rejuvenate the immune system, which becomes exhausted as it responds to cancer.
“Immune cells play a very important role in cancer treatment,” Safe said. “But what happens with tumor development is that eventually, the immune cells just get exhausted and become unable to mount a ‘tumor-killing’ response.
“Dr. Jim Allison and Dr. Tasuku Honjo’s Nobel Prize-winning work found that at least one of the reasons the immune cells don’t work is that they’re not only exhausted, but they don’t function because tumors can suppress immune cells, especially T-cells (which target specific foreign particles, such as cancer cells) and thereby avoid immune cell-dependent tumor surveillance (the tumors are misidentified as immune cells by the immune system),” Safe said.
Immunotherapies work by separating the T-cells from the tumor, allowing the immune system to destroy the tumor the way it would any other infection in your body.
“One of the signals (the communication mechanism between T-cells and tumors), or checkpoints, is a gene called PD-L1, which is a checkpoint inhibitor; checkpoints bring the immune cell and the tumor cell together,” Safe said. “We found that in breast and colon cancer, NR4A1 regulates PD-L1 in the tumor, and treatment with our antagonist decreases PD-L1 expression and sensitizes the tumor to immune surveillance, killing it.”
By isolating the immune cells, Wright, an associate research scientist in the VMBS’ Department of Veterinary Pathobiology, was able to analyze the T-cells for markers of exhaustion and determined that with Safe’s compounds, those markers were “wiped out.”
“Previous studies showed that NR4A1 played a role in T-cell exhaustion, and our unique NR4A1 antagonists not only target NR4A1 in the tumor but also in T-cells; this dual targeting (the killing of the tumor and rejuvenating the immune system) is consistent with their high anticancer activity in mouse models.”
In the next phase of their research, the team will use the NIH grant to explore other areas of how the compounds work to, hopefully, prepare it for clinical trials.
While Safe works to “maximize” the compounds—that is, to select the most effective molecules for achieving their end goal—and to assess compound dosages, Abdelrahim, who is co-principal investigator on the project, will be examining the effects of the compound on human tissue; Wright will be working to further explore implications on the immune system; Cai, an associate professor in the VMBS’ Department of Integrative Biosciences, will be investigating how other individual cell types are affected by the compounds; and Chapkin, the Allen Endowed Chair in Nutrition & Chronic Disease Prevention and a University Distinguished Professor, will be further analyzing effects of NR4A1-targeting compounds on colonic epithelial stem cells in tumors.
Chapkin, Wright, and Cai will also perform a single cell multi-omic analysis of the colon tumor microenvironment to probe the mechanistic underpinnings of NR4A1-dependent modulation of T-cell exhaustion.
Ultimately, Safe believes their NR4A1-targeting drugs will also attenuate other types of cancer, including breast cancer, glioblastoma, and rhabdomyosarcoma, the most common soft tissue sarcoma in children.
“A lot of drugs that oncologists use now just target the specific genes/pathways in tumor cell—the drug kills it and the tumor usually regresses,” he said. “Those drugs are effective and inhibit some tumor growth, but they’re only targeting the tumor; they’re not targeting immune cells. I’m not sure how many drugs currently being used target both the tumor and the immune cells, but ours do, and this accounts for their potency in preclinical animal models.”
Contact Information: Jennifer Gauntt, Director of VMBS Communications, Texas A&M School of Veterinary Medicine & Biomedical Sciences; email@example.com; 979-862-4216
Congratulations! Dr. Robert S. Chapkin has been reappointed as the holder of the William W. Allen Chair in Nutrition & Chronic Disease Prevention in the Department of Nutrition for a second 5-year term from December 1, 2022 to November 30, 2027.
As the holder of the William W. Allen Chair in Nutrition since December 1, 2017, Dr. Chapkin’s research has transformed the cancer chemoprevention field by demonstrating the utility of plasma membrane nanodomain and aryl hydrocarbon (AhR) nuclear receptor targeted therapies to suppress oncogenic signaling. He also spearheaded the discovery of the field of non-invasive precision nutrition, i.e., mRNA-based applications using stool derived exfoliated cells for assessing host responsiveness to diet. This transformative body of work has enabled multi-omic longitudinal applications in deep phenotyping related to the analysis of gut microbe (prokaryotic) and host (eukaryotic) crosstalk in response to diet and chronic disease risk.
Dr. Chapkin is an exceptionally productive scientist, having published 300 peer-reviewed manuscripts (70 since 2017), 27 book chapters, 316 abstracts, and is listed as co-inventor on three patents. The fact that his papers have been cited over 18,810 times (>5,254 times since 2018) and have an h-index of 76 (37 since 2018) clearly demonstrates that Dr. Chapkin continues to have a significant impact in his discipline and has achieved an exceptional level of scholarship.
Dr. Chapkin is currently a University Distinguished Professor, Regents Professor, University Faculty Fellow, and Allen Endowed Chair in Nutrition & Chronic Disease Prevention. He was recognized as an American Association for the Advancement of Science (AAAS) Fellow (2018) and awarded a highly prestigious National Cancer Institute (NCI) R35 Outstanding Investigator Award (2016-2023) to extend novel cancer prevention strategies to delineate the nuclear and plasma membrane targeted mechanisms modulating stem cell responses to exogenous (diet-derived) and endogenous (gut microbial) bioactive agents.