Molecular Pathobiology of Gastric Carcinogenesis

Significance to VA: Infection with Helicobacter pylori (H. pylori), a Class I carcinogen, is the primary risk factor for gastric cancer. Among veterans, H. pylori infection prevalence is approximately 35%, with significantly higher rates in military personnel aged 17-25 years compared to civilians. This alarming trend may be linked to recent deployments to regions with high H. pylori prevalence. In the United States, gastric cancer patients are often diagnosed at advanced stages III and IV, with poor response to therapy . This proposal addresses critical knowledge gaps in gastric tumorigenesis mechanisms and integrates mechanistic insights to understand the biology with translational approaches to overcome chemotherapeutic resistance. Innovation and Impact: This proposal introduces the innovative concept of GLI2 as a signaling bridge between infection and inflammation (NF-kB) in gastric tumorigenesis. The research employs cutting-edge tools and technologies, including organoid cultures, the TFF1 KO mouse model that develops neoplastic lesions and molecular alterations similar those in humans, and advanced molecular techniques such as spatial mass cytometry CyTOF, Cytek-Aurora spectral flow cytometry, and integrated RNA-seq and ChIP-seq analysis. The findings will impact our understanding the role of GLI2 in the survival and expansion of tumorigenic cells, a major cause of resistance to therapy. The results can support future clinical trials that optimize responses to chemotherapy or immune checkpoint blockade (ICB) to ablate treatment-resistant cells. Specific Aims: We hypothesize that gastric cells develop resilience and survival properties in response to infection and chemotherapeutics through activation of the GLI2 signaling pathway. To investigate this hypothesis and its implications, we propose three specific aims that address the mechanistic, functional, and translational significance. Aim 1 will investigate the role of infection and chemotherapy in activating GLI2. In Aim 2, we plan to determine the downstream molecular and biological functions of the GLI2 network in gastric tumorigenesis. Aim 3 will investigate the translational significance of GLI2 activation in human gastric tumorigenesis. Spatial single cell molecular technologies will be utilized to detect spatial expression changes in gastric glands and surrounding immune cells using de-identified gastric cancer tissues. Additionally, we will assess the therapeutic effectiveness of targeting GLI2, either individually or in combination with standard-of- care treatments or ICB, using in vivo models of gastric tumorigenesis. Methodology: The study will utilize in vitro and in vivo models to investigate molecular and biological responses to H. pylori infection and chemotherapeutics under conditions of overexpression or knockdown of candidate genes. Molecular techniques will include assays for the quantification of RNA and protein levels, luciferase reporter assays, and immunohistochemical and immunofluorescence analyses. Advanced molecular technologies will involve the use of spatial mass cytometry (CyTOF), Cytek-Aurora spectral flow cytometry, and integrated RNA-seq and ChIP-seq analyses. Path to Translation/Implementation: This research bridges basic science and translational/clinical applications, potentially improving patient outcomes in the future. Studies in Aim 2 will characterize novel molecular mechanisms of resistance to therapeutics. Aim 3 will investigate the translational significance of GLI2 activation using de-identified gastric cancer patients tissue samples. Additionally, we will assess the therapeutic effectiveness of targeting GLI2, either individually or in combination with standard-of-care treatments or ICB, using in vivo models of gastric tumorigenesis. Results can support future clinical trials that optimize responses to chemotherapy or ICB to ablate to achieve optimal therapeutic efficacy. Project Number: 2I01RD001338-13 | Fiscal Year: 2026 | NIH Institute/Center: Veterans Affairs (VA) | Principal Investigator: WAEL EL-RIFAI | Institution: MIAMI VA HEALTH CARE SYSTEM, MIAMI, FL | Activity Code: I01 | Study Section: Special Emphasis Panel[ZRD1 GAST-L (01)] View on NIH RePORTER: https://reporter.nih.gov/project-details/11293482