👤 M Hoshi

Muscle-invasive bladder cancer (MIBC) is an aggressive malignancy with high recurrence and poor survival, accounting for the majority of bladder cancer-related deaths. A subset of MIBC harbors FGFR1 amplification or overexpression, associated with increased proliferation and poor prognosis. Although the pan-FGFR inhibitor erdafitinib has demonstrated clinical benefit in patients with FGFR3/FGFR2 alterations, primarily in non-MIBC, its efficacy is limited by resistance and toxicity. Moreover, its effectiveness in FGFR1-driven MIBC remains unclear. To address this gap, we investigated erdafitinib response and resistance mechanisms in JMSU1 cells, a model of FGFR1-amplified MIBC. While erdafitinib initially suppressed tumor growth, prolonged treatment led to resistance, characterized by persistent activation of ERK, AKT, and STAT1 signaling pathways. Mechanistic studies identified MET activation, driven by MET gene amplification, as a key driver of resistance. Notably, exogenous hepatocyte growth factor (HGF) not only induced resistance but also accelerated the emergence of MET-amplified, HGF-independent subpopulations under drug pressure. We also identified SHP2 as a critical mediator of FGFR1-driven ERK activation in parental cells. In resistant cells, MET activation enhanced SHP2-ERK signaling through the adaptor protein GAB1, reinforcing the resistant phenotype. Combined inhibition of FGFR1 and MET significantly suppressed tumor growth in resistant cells. These findings establish MET amplification and GAB1-SHP2 signaling as central mediators of erdafitinib resistance in FGFR1-amplified MIBC and support dual FGFR1/MET targeting as a promising therapeutic strategy. Show less

Hypothermia is an important cause of death in forensic pathology. For the forensic diagnosis of hypothermia, some reports point out the possibility that hypothermia without diabetes may cause ketoacidosis. In this study, we evaluated the diagnostic value of ketoacidosis in a murine model of hypothermia, using the cold stress at 4 °C for 3 or 5 hrs in genetically diabetic (BKS.Cg-+Lepr Show less

DUSP6 (alias PYST1), one of the dual-specificity tyrosine phosphatases, is localized on 12q21, one of the regions of frequent allelic loss in pancreatic cancer. This gene is composed of three exons, and two forms of alternatively spliced transcripts are ubiquitously expressed. Although no mutations were observed in 26 pancreatic cancer cell lines, reduced expressions of the full-length transcripts were observed in some cell lines, which may suggest some role for DUSP6 in pancreatic carcinogenesis. Show less