Poster Session A   |   11:45am Expo - Hall A & C   |   Poster ID #115

AdipoRon attenuates Lgr5+ stem cell Wnt signaling and oncogenic APC-driven colonic polyp formation by reducing cholesterol-dependent plasma membrane rigidity and Wnt nanocluster formation

Academic Research
Prevention, Early Detection, Implementation, and Dissemination
FDA Status:
Not Applicable
CPRIT Grant:
Cancer Site(s):
Michael L. Salinas
Texas Agrilife Research
Natividad Roberto Fuentes
The University of Texas M.D. Anderson Cancer Center
Xiaoli Wang
Baylor College of Medicine
Chapkin S. Chapkin
Texas Agrilife Research


The increasing prevalence of adult and adolescent obesity and its associated risk of colorectal cancer (CRC) reinforces the urgent need to elucidate the underlying mechanisms contributing to cancer promotion in obese individuals. Adiponectin is an adipose tissue-derived adipokine, whose levels are often reduced in CRC patients and during obesity. Under high-fat diet feeding conditions, adiponectin knockout mice develop more colonic polyps in both genetically-driven and carcinogen-induced CRC mouse models. Conversely, both epidemiological and preclinical data indicate that adiponectin suppresses colon tumorigenesis. We have previously demonstrated that both adiponectin and AdipoRon, a small-molecule Adiponectin Receptor agonist, suppress CRC risk in part by reducing the number of Lgr5+ stem cells, the cells-of-origin in intestinal cancer, in mouse colonic 3D organoids. However, the mechanism by which adiponectin signaling attenuates CRC risk remains to be addressed. Here, we have hypothesized that adiponectin signaling supports colonic stem cell homeostasis via modulation of plasma membrane lipid composition and organization. This is significant, because plasma membrane biochemical and biophysical properties determine the spatial compartmentalization of signaling components which regulate downstream signal transduction. Thus, it is increasingly clear than the plasma membrane serves as a nexus integrating protein and lipid components into cholesterol-enriched lipid rafts exhibiting distinct biophysical properties that modulate various signaling events at the plasma membrane.


Complementary in vivo and ex vivo oncogenic-APC mouse models including 3D colonic organoids were utilized. Mice were fed a high-fat diet over 12 weeks to induce obesity and the effect of AdipoRon oral administration was assessed. Colonocyte plasma membrane biophysical properties and unesterified (free) cholesterol content were determined utilizing the physicochemical sensitive dye, Di-4-ANEPPDHQ and Filipin III, respectively. Confocal microscopy and image-based flow cytometry were utilized as orthogonal approaches to measuring plasma membrane rigidity and cholesterol levels. Total internal reflection fluorescence (TIRF) combined with super-resolution stochastic optical reconstruction microscopy (STORM) was utilized to determine the nanoscale clustering of Wnt receptor, LRP6. Effects of nanoclustering on the activation status of downstream signaling targets was subsequently assessed.


Oncogenic-APC mice tjat were administered the AdipoRon therapeutic developed fewer colonic polyps compared to oncogenic-APC mice that were administered the drug vehicle (control) alone. Based on experiments utilizing the membrane order dye, Di-4-ANEPPDHQ, AdipoRon also decreased colonocyte plasma membrane rigidity which was associated with a reduction in plasma membrane free cholesterol and the intracellular accumulation of free cholesterol in lysosomes. Furthermore, AdipoRon reduced Wnt co-receptor (LRP6) plasma membrane nanocluster assembly, downstream Wnt/β-catenin-reporter signaling, and cell proliferation


In an oncogenic-APC mouse model of CRC, oral administration of AdipoRon reduced the progression of colonic polyp formation in part by attenuating elevated colonocyte plasma membrane free cholesterol and rigidity. These novel findings suggest that adiponectin signaling plays a role in modulating cellular cholesterol homeostasis, plasma membrane biophysical properties, and downstream Wnt signaling. These findings are noteworthy because they may in part explain how obesity promotes CRC and supports the feasibility of utilizing membrane therapy, i.e., dietary/drug-related strategies to target plasma membrane dysregulation, to reduce cancer risk.