Résumé
To study the molecular mechanism for DNA hypomethylation of STAT3 promoter in CD4+ T cells from acute graft-versus-host disease (aGVHD) patients. Methods: We collected CD4+ T cells from peripheral blood of 42 patients who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) from HLA-identical sibling donors. GADD45A expression level in CD4+ T cells was measured by real-time PCR and Western blot. The binding level between HMGB1 and GADD45A in CD4+ T cells was analyzed by co-immunoprecipitation, while the binding levels of HMGB1/GADD45A with STAT3 promoter were detected by chromatin immunoprecipitation-quantitative real-time PCR (ChIP-qPCR). After overexpression of HMGB1 and knockdown of GADD45A in normal CD4+ T cells, STAT3 expression and DNA methylation were measured by Western blot and bisulfite sequencing PCR, respectively. Results: GADD45A expression was significantly up-regulated in patients with aGVHD compared with that in the patients without aGVHD. More HMGB1-GADD45A complexes were found in CD4+ T cells from patients with aGVHD compared with that in patients without aGVHD. The bindings of HMGB1/GADD45A with STAT3 promoter were significantly increased, and the binding levels of HMGB1/GADD45A were negatively correlated with STAT3 promoter DNA methylation. The expression of STAT3 was significantly reduced and the DNA methylation of STAT3 promoter was significantly increased in CD4+ T cells with overexpression of HMGB1 and knockdown of GADD45A compared with CD4+ T cells only with overexpression of HMGB1. Conclusion: The increased expression of HMGB1/GADD45A plays an importent role in STAT3 promoter DNA hypomethylation, thereby promoting STAT3 expression in CD4+ T cells from aGVHD patients.
Sujets)
Humains , Lymphocytes T CD4+ , Protéines du cycle cellulaire , Métabolisme , Déméthylation de l'ADN , Régulation de l'expression des gènes , Génétique , Maladie du greffon contre l'hôte , Génétique , Protéine HMGB1 , Métabolisme , Transplantation de cellules souches hématopoïétiques , Protéines nucléaires , Métabolisme , Régions promotrices (génétique) , Génétique , Facteur de transcription STAT-3 , Génétique , MétabolismeRésumé
Object To evaluate the efficacy and toxicity of L-asparaginase based regimen for extranodal nasal type NK/T cell lymphoma (ENKTL).Methods 36 patients were treated with L-asparaginase based regimen from February 2008 to November 2011. 20 stage Ⅰ /Ⅱ patients were administered with VLD regimen based chemo-radiotherapy. 4 of 16 stage Ⅲ/Ⅳ patients received modified SMILE regimen chemotherapy, followed by involved field radiation therapy (IFRT), while others received modified SMILE regimen chemotherapy alone.Results Among 36 patients,35 were eligible for treatment response evaluation.The overall response rate (RR) was 68.6％ (24/35) with complete response (CR) rate of 54.3％ (19/35).After the median follow-up of 13.5 (range 3-31) months,for all patients,the 1-year overall survival (OS) rate was 82 ％,and the rate of progression-free survival (PFS) at 1 year was 65 ％.The patients who attained response with treatment showed better 1-year OS (93 ％) and PFS (80 ％) as compared with patients without response (35 ％; 33 ％),and the differences were statistically significant (x2=13.909,P =0.000; x2=8.216,P =0.004).The major adverse event was myelosuppression. No chemotherapy-related mortality occurred. Conclusion L-asparaginase based regimen is obviously effective and well tolerant for ENKTL. The large prospective clinical trials of L-asparaginase based regimen in the first-line treatment for ENKTL are worth for further investigation.