정재호 교수

OBJECTIVE: We investigated microsatellite instability (MSI) status and programed cell death ligand 1 (PD-L1) expression as predictors of prognosis and responsiveness to chemotherapy for stage II/III gastric cancer. BACKGROUND: The clinical implications of MSI status and PD-L1 expression in gastric cancer have not been well-elucidated. METHODS: Tumor specimens and clinical information were collected from patients enrolled in the CLASSIC trial-a randomized controlled study of capecitabine plus oxa

Tumor cell proliferation requires both growth signals and sufficient cellular bioenergetics. The AMP-activated protein kinase (AMPK) pathway seems dominant over the oncogenic signaling pathway suppressing cell proliferation. This study investigated the preclinical efficacy of targeting the tumor bioenergetic pathway using a glycolysis inhibitor 2-deoxyglucose (2DG) and AMPK agonists, AICAR and metformin. We evaluated the in vitro antitumor activity of 2DG, metformin or AICAR alone, and 2DG in co

Genomic profiling can provide prognostic and predictive information to guide clinical care. Biomarkers that reliably predict patient response to chemotherapy and immune checkpoint inhibition in gastric cancer are lacking. In this retrospective analysis, we use our machine learning algorithm NTriPath to identify a gastric-cancer specific 32-gene signature. Using unsupervised clustering on expression levels of these 32 genes in tumors from 567 patients, we identify four molecular subtypes that are

The patient-derived xenograft (PDX) model is emerging as a promising translational platform to duplicate the characteristics of tumours. However, few studies have reported detailed histological and genomic analyses for model fidelity and for factors affecting successful model establishment of gastric cancer. Here, we generated PDX tumours surgically-derived from 62 gastric cancer patients. Fifteen PDX models were successfully established (24.2%, 15/62) and passaged to maintain tumours in immune-

Increased oxidative phosphorylation (OXPHOS) and reactive oxygen species (ROS) levels are inherently linked. ROS are essential signaling molecules, with detrimental effects when produced in excess during chemotherapy, leading to cell death. Cancer stem-like cells (CSCs) are a subpopulation of tumor cells resistant to chemotherapy, highly invasive and metastagenic, driving malignant cancer behavior. In this study, we demonstrated that CSCs exhibit increased OXPHOS but paradoxically low ROS levels

Metabolic and genotoxic stresses that arise during tumor progression and anti-cancer treatment, respectively, can impose a selective pressure to promote cancer evolution in the tumor microenvironment. This process ultimately selects for the most "fit" clones, which generally have a cancer stem cell like phenotype with features of drug resistance, epithelial-mesenchymal transition, invasiveness, and high metastatic potential. From a bioenergetics perspective, these cancer stem-like cells (CSCs) e

Gastric cancer (GC) is a common aggressive malignant tumor with high incidence and mortality worldwide. GC is classified into intestinal and diffuse types according to the histo-morphological features. Because of distinctly different clinico-pathological features, new cancer therapy strategies and in vitro preclinical models for the two pathological variants of GC is necessary. Since extracellular matrix (ECM) influence the biological behavior of tumor cells, we hypothesized that GC might be mor

During gastric cancer (GC) progression, increased extracellular matrix (ECM) deposition, notably collagen type I, correlates with an overall increase in expression of the mesenchymal phenotype. In GC tissue, the intestinal epithelium exhibits impaired cell-cell adhesion and enhanced cell-ECM adhesion. The alteration of intercellular integrity is one of tumorigenesis feature including tumor invasion and metastasis. Using a density-varying ECM, we studied the effect of ECM density on both intercel

The small GTP-binding protein Rab25 is associated with tumor formation and progression. However, recent studies have shown discordant effects of Rab25 on cancer cell progression depending on cell lineage. In the present study, we elucidate the underlying mechanisms by which Rab25 induces cellular invasion. We demonstrate that Rab25 increases β1 integrin levels and subsequent activation of EGFR and upregulation of VEGF-A expression, leading to increased Snail expression, epithelial-to-mesenchymal