Biology subjects

Moussalli, M. J.

Publications and source records attributed to Moussalli, M. J..

4 recordsLinked to original sources

bioRxiv2020

Ppard is Essential in Acceleration of Pancreatic Ductal Adenocarcinoma Development by High-Fat Diet in Mutant Kras Mice

Pro-obesity high-fat diet is linked with an increased incidence of pancreatic cancers, but the molecular underpinnings of this association remain poorly understood. Here, we report that PPARD is upregulated in pancreatic intraepithelial neoplasia lesions (PanINs) at early stages of pancreatic tumorigenesis in humans and mutant Kras mice. Transgenic overexpression of Ppard in pancreatic epithelial cells drastically accelerates the development and progression of pancreatic ductal adenocarcinoma in mutant Kras mice when activated by feeding the mice with a high-fat diet or a diet containing GW501516 (50 mg/kg), a selective PPARD agonist. In contrast, pancreatic Ppard genetic deletion significantly suppressed the promotion of pancreatic tumorigenesis by these diets. Mechanistically, we found that this Ppard hyperactivation in pancreatic epithelial cells of mutant Kras mice increased production of chemokines and cytokines (e.g., CcI2, CcI4-5, CxcI5 and II6), leading to the robustly increased recruitment of myeloid-derived suppressor cells and macrophages into pancreata, which fostered an immune suppressive microenvironment and subsequently accelerated pancreatic ductal adenocarcinoma development and progression. Our findings demonstrate that PPARD plays an essential role in the promotion of pancreatic tumorigenesis by a high-fat diet. Targeted inhibition of PPARD activation is a potential interventive strategy for pancreatic cancer prevention and therapy.

cancer biology↗

bioRxiv2019

Suppression of membranous LRP5 recycling, WNT/β-catenin signaling, and colorectal tumorigenesis by 15-LOX-1 peroxidation of PI3P_linoleic acid

Aberrant Wnt/{beta}-catenin activation is a major driver of colorectal cancer (CRC), which is typically initiated by APC mutations. Additional modifiable factors beyond APC mutations have been recognized to be important for further potentiation of aberrant {beta}-catenin activation to promote colorectal tumorigenesis. These factors have yet to be clearly identified. Western-type diets are increasingly enriched in linoleic acid (LA). LA-enriched diet however promotes chemically-induced colorectal tumorigenesis in rodent models. Furthermore, the main metabolizing enzyme of LA, 15-lipoxygenase-1 (15-LOX-1), is transcriptionally silenced in CRC. Whether LA and 15-LOX-1 affect Wnt/{beta}-catenin signaling to modulate colorectal tumorigenesis is poorly understood. Herein, we report that high dietary LA promoted colorectal tumorigenesis in mice with intestinally targeted APC mutation (Apc{Delta}580) by upregulating a Wnt receptor, LRP5 expression, and {beta}-catenin activation. 15-LOX-1 transgenic expression in intestinal epithelial cells suppressed LRP5 expression, {beta}-catenin activation and subsequently CRC in these mice. In particular, 15-LOX-1 peroxidation of LA in phosphatidylinositol-3-phosphates (PI3P_LA) into PI3P_13-HODE decreased PI3P binding to SNX17and LRP5, which inhibited LRP5 recycling from endosomes to the plasma membrane, thereby leading to an increase of LRP5 lysosomal degradation. Our findings demonstrate for the first time that 15-LOX-1 metabolism of LA in PI3P to regulate LRP5 membrane abundance is a modifiable factor of Wnt/{beta}-catenin aberrant signaling that could be potentially therapeutically targeted to suppress colorectal tumorigenesis and progression.

cancer biology↗

bioRxiv2018

Pleotropic effects of PPARD accelerate colorectal tumor progression and invasion

Colorectal carcinogenesis (CRC) progression requires additional molecular mechanisms to APC mutations/aberrant {beta}-catenin signaling. PPARD is a druggable ligand-activated nuclear receptor that regulates essential genes involved in cell fate. PPARD is upregulated in intestinal epithelial cells (IECs) of human colorectal adenomas and adenocarcinomas. The mechanistic significance of PPARD upregulation in CRC remains unknown. Here we show that targeted PPARD overexpression in IECs of mice strongly augmented {beta}-catenin activation via BMP7/TAK1 signaling, promoted intestinal tumorigenesis in Apcmin mice, and accelerated CRC progression and invasiveness in mice with IEC-targeted Apc{Delta}580 mutation. Human CRC invasive fronts had higher PPARD expression than their paired adenomas. A PPARD agonist (GW501516) enhanced APC{Delta}580 mutation-driven CRC, while a PPARD antagonist (GSK3787) suppressed it. Functional proteomics analyses and subsequent validation studies uncovered PPARD upregulation of multiple pro-invasive pathways that drive CRC progression (e.g. PDGFR{beta}, AKT1, CDK1 and EIF4G1). Our results identify novel mechanisms by which PPARD promotes CRC invasiveness and provide the rational for the development of PPARD antagonists to suppress CRC.

cancer biology↗

bioRxiv2017

PPARD regulation in gastric progenitor cells drives gastric tumorigenesis in mice

Little is known about the cell origin of gastric cancer. Peroxisome proliferator-activated receptor-delta (PPARD) is a druggable ligand-activated nuclear receptor that impacts protumorigenic cellular events. However, PPARDs role in tumorigenesis, especially gastric tumorigenesis, remains to be defined. We found that targeting PPARD overexpression in murine gastric progenitor cells (GPC), via a villin promoter, spontaneously induced gastric tumorigenesis that progressed to invasive adenocarcinoma. PPARD overexpression in GPC upregulated tumorigenic proinflammatory cytokine and CD44 expression, expanded GPC population in vivo, enhanced GPC self-renewal and proliferation in organoid cultures, and endowed these cells with tumorigenic properties. Our findings identify PPARD as a driver of gastric tumorigenesis via GPC transformation.

cancer biology↗