👤 Yukiko Nishita

The apolipoprotein E ε4 (APOE ε4) allele, a major genetic risk factor for Alzheimer's disease, is associated with early atrophy in the precuneus and posterior cingulate cortex. Whether physical activity can mitigate this atrophy in high-risk APOE ε4 carriers remains unclear. This study aimed to determine whether physical activity can reduce such neurodegenerative changes in older adults carrying this allele. This 10-year longitudinal study included 295 community-dwelling older adults (154 men and 141 women; age ≥65 years). Baseline physical activity was measured using accelerometers and analyzed according to activity intensity. Participants were categorized as APOE ε4 carriers or non-carriers. Volumes of the precuneus and posterior cingulate cortex were assessed using longitudinal magnetic resonance imaging. Sex-stratified linear mixed models examined the interaction between physical activity and APOE ε4 status on brain volume changes, adjusting for relevant covariates. The moderate-to-vigorous physical activity (MVPA) × APOE ε4 × year effect in women's left precuneus was significant unadjusted but not after false discovery rate (FDR; 16 models) and exploratory. Left precuneus volume declined significantly over 10 years regardless of MVPA level or APOE ε4 genotype (each p < 0.0001). However, among APOE ε4 carriers, greater time spent in MVPA slowed the rate of volume decline. No similar effect was observed in men. Higher habitual MVPA may be associated with slower left precuneus decline in APOE ε4-positive women. As this exploratory three‑way effect was FDR‑nonsignificant, targeted replication is needed to clarify the role of everyday activity in genetically vulnerable groups. Show less

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