Background: The tight junction protein claudin18.2 (CLDN18.2) has been implicated in poor prognosis and suboptimal immunotherapy response in gastric cancer (GC). This study investigates the clinicopathological relevance of CLDN18.2 expression and its association with molecular subtypes in GC patients from a high-incidence region, combining transcriptomic and proteomic approaches to explore how CLDN18.2 contributes to progression and metastasis. Methods: A retrospective cohort of 494 GC patients (2019–2024) underwent immunohistochemical analysis for CLDN18.2, Epstein-Barr virus (Epstein–Barr virus–encoded RNA), p53, human epidermal growth factor receptor 2 (HER2), and mismatch repair proteins (MLH1, MSH2, PMS2, and MSH6). CLDN18.2 positivity was defined as moderate to strong (2+/3+) membranous staining in ≥75% of tumor cells. Clinicopathological correlations, biomarker associations, and survival outcomes were evaluated. Transcriptomic and proteomic sequencing was performed to explore molecular mechanisms. Results: CLDN18.2 positivity was observed in 26.9% (133/494) of gastric adenocarcinomas. CLDN18.2-positive tumors correlated with TNM stage (p = .003) and shorter overall survival (p = .018). No associations were identified with age, sex, HER2 status, microsatellite instability, or Epstein-Barr virus infection. Transcriptomic profiling revealed CLDN18.2-high tumors enriched in pathways involving cell junction disruption, signaling regulation, and immune modulation. Proteomic profiling showed that tumors with high CLDN18.2 were enriched in multiple mechanism-related pathways such as integrated metabolic reprogramming, cytoskeletal recombination, immune microenvironment dysregulation, and pro-survival signaling. These mechanisms may collectively contribute to tumor progression and metastasis. Conclusions CLDN18.2 overexpression is associated with poor prognosis in GC patients. Transcriptomic and proteomic analyses demonstrate that CLDN18.2 promotes tumor progression and metastasis, underscoring its potential as an independent prognostic factor in regions with a high incidence of GC.

Objective To observe the changes of short-chain acyl-CoA dehydrogenase (SCAD) expression on human umbilical vein endothelial cell (HUVEC) apoptosis and investigate its relationship with apoptosis. Methods The HUVEC was cultured normally for 2-3 days. The apoptotic model of HUVEC was established by tert-butyl hydrogen peroxide (tBHP). The HUVEC was treated by different concentrations of tBHP (0, 10, 20, 30, 40, 50 μmol/L) for 12 hours and different time (0, 3, 6, 9, 12 hours) with 50 μmol/L tBHP to establish the apoptotic model of HUVEC. The cell viability was detected by methyl thiazolyl tetrazolium (MTT), the mRNA expression of SCAD was determined by real-time polymerase chain reaction (PCR), the protein expression of SCAD was achieved by Western Blot. The best concentrate and time were determined to interfere the HUVEC to achieve the apoptotic model of HUVEC. The SCAD gene of HUVEC was knocked down by RNA interference sequence (siRNA274, siRNA414, siRNA679). The mRNA expression of SCAD, the protein expression of SCAD and the activity of SCAD enzyme were detected to achieve the best RNA interference sequence. The HUVEC was intervened by the best RNA interference sequence and tBHP. The cell activity and apoptosis rate, the enzyme activity of SCAD, the mRNA and protein expression of SCAD, the contents of reactive oxygen species (ROS), aderosine triphosphate (ATP) and free fatty acid (FFA) were detected to observe the effect of SCAD on apoptosis of HUVEC. Results ① The cell viability, the mRNA expression and the protein expression of SCAD were decreased gradually in a concentration and time dependent manner with the increase of tBHP concentration and the prolongation of intervention time. The decline was most significant in the group of the 50 μmol/L tBHP to interfere HUVEC for 12 hours. ② The siRNA679 transfection was the most significant in reducing SCAD mRNA and protein expressions among the three interference sequences (siRNA274, siRNA414, siRNA679). ③ Compare with blank control group, the cell viability was significantly decreased in the siRNA679 group (A value: 0.48±0.09 vs. 1.00±0.09, P < 0.01), the apoptotic rate of HUVEC was significantly increased [(29.96±2.09)% vs. (2.90±1.90)%, P < 0.01], the expression of SCAD mRNA and SCAD protein, the activity of SCAD enzyme and the content of ATP were significantly decreased [SCAD mRNA (2-ΔΔCt): 0.50±0.16 vs. 1.34±0.12, SCAD/α-Tubulin: 0.67±0.11 vs. 1.00±0.06, the activity of SCAD enzyme (kU/g): 0.38±0.04 vs. 0.53±0.04, the content of ATP (μmol/g): 0.14±0.02 vs. 0.19±0.01, all P < 0.05], the contents of FFA and ROS were significantly increased [FFA (nmol/g): 0.84±0.07 vs. 0.47±0.04, ROS (average fluorescence intensity): 647.5±23.7 vs. 434.2±46.5, both P < 0.01]. Meanwhile, SCAD siRNA treatment triggered the same apoptosis as HUVEC treated with tBHP. Conclusions Down-regulation of SCAD may play an important role in HUVEC apoptosis. Increase in the expression of SCAD may become an important part in intervening HUVEC apoptosis.

Objective? To?Study?the?changes?of?short-chain?acyl-CoA?dehydrogenase?(SCAD)?in?heart?failure?(HF)?after?myocardial?infarction?(MI),?and?the?effect?of?aerobic?exercise?on?SCAD.? Methods? Healthy?male?Sprague-Dawley?(SD)?rats?were?divided?into?sham?operation?group?(Sham?group),?sham?operation?swimming?group?(Sham+swim?group),?HF?model?group?(LAD?group)?and?HF?swimming?group?(LAD+swim?group)?by?random?number?table?method,?with?9?rats?in?each?group.?The?left?anterior?descending?branch?of?coronary?artery?(LAD)?was?ligated?to?establish?a?rat?model?of?HF?after?MI.?In?Sham?group,?only?one?loose?knot?was?threaded?under?the?left?coronary?artery,?and?the?rest?operations?were?the?same?as?those?in?LAD?group.?Rats?in?Sham+swim?group?and?LAD+swim?group?were?given?swimming?test?for?1?week?after?operation?(from?15?minutes?on?the?1st?day?to?60?minutes?on?the?5th?day).?Then?they?were?given?swimming?endurance?training?(from?the?2nd?week?onwards,?60?minutes?daily,?6?times?weekly,?10?weeks?in?a?row).?Tail?artery?systolic?pressure??(SBP)?was?measured?before?swimming?endurance?training?and?every?2?weeks?until?the?end?of?the?10th?week.?Ten?weeks?after?swimming?training,?echocardiography?was?performed?to?measure?cardiac?output?(CO),?stroke?volume?(SV),?left?ventricular?ejection?fraction?(LVEF),?shortening?fraction?(FS),?left?ventricular?end-systolic?diameter?(LVESD),?left?ventricular?end-diastolic?diameter?(LVEDD),?left?ventricular?end-systolic?volume?(LVESV),?and?left?ventricular?end-diastolic??volume?(LVEDV).?Morphological?changes?of?heart?were?observed?by?Masson?staining.?Apoptosis?of?myocardial?cells?was?detected?by?transferase-mediated?deoxyuridine?triphosphate-biotin?nick?end?labeling?stain?(TUNEL)?and?apoptosis?index?(AI)?was?calculated.?Reverse?transcription-polymerase?chain?reaction?(RT-PCR)?and?Western?Blot?were?used?to?detect?the?mRNA?and?protein?expression?of?myocardial?SCAD?respectively.?In?addition,?the?enzyme?activity?of?SCAD,?the?content?of?adenosine?triphosphate?(ATP)?and?free?fatty?acid?(FFA)?in?serum?and?myocardium?were?detected?according?to?the?kit?instruction?steps.? Results? Compared?with?Sham?group,?Sham+swim?group?showed?SBP?did?not?change?significantly,?with?obvious?eccentric?hypertrophy?and?increased?myocardial?contractility,?and?LAD?group?showed?persistent?hypotension,?obvious?MI,?thinning?of?left?ventricle,?and?decreased?myocardial?systolic/diastolic?function.?Compared?with?LAD?group,?SBP,?systolic/diastolic?function?and?MI?in?LAD+swim?group?were?significantly?improved?[SBP?(mmHg,?1?mmHg?=?0.133?kPa):?119.5±4.4?vs.?113.2±4.5?at?4?weeks,?120.3±4.0?vs.?106.5±3.7?at??6?weeks,?117.4±1.3?vs.?111.0±2.3?at?8?weeks,?126.1±1.6?vs.?119.4±1.9?at?10?weeks;?CO?(mL/min):?59.10±6.31?vs.?33.19±4.76,?SV?(μL):?139.42±17.32?vs.?84.02±14.26,?LVEF:?0.523±0.039?vs.?0.309±0.011,?FS:?(28.17±2.57)%?vs.?(15.93±3.64)%,?LVEDD?(mm):?8.80±0.19?vs.?9.35±0.30,?LVESD?(mm):?5.90±0.77?vs.?7.97±0.60,?LVEDV?(μL):?426.57±20.84?vs.?476.24±25.18,?LVESV?(μL):?209.50±25.18?vs.?318.60±16.10;?AI:?(20.4±1.4)%?vs.?(31.2±4.6)%;?all?P??0.05).? Conclusion? The?expression?of?SCAD?in?HF?was?significantly?down-regulated,?and?the?expression?was?significantly?up-regulated?after?aerobic?exercise?intervention,?indicating?that?swimming?may?improve?the?severity?of?HF?by?up-regulating?the?expression?of?SCAD.