title: Up-regulation of VEGF and its receptor in refractory leukemia cells.
abstract: OBJECTIVE
  To analyze the causative mechanisms in refractory leukemia cells.
  
  
  METHODS
  Vascular endothelial growth factor (VEGF) blood plasma concentrations in 35 de novo, 6 relapse, 20 remission leukemia patients and 10 healthy kids were determined via ELISA analyses. Transcription levels of the VEGF receptors (VEGFR) Fms-like tyrosine kinase-1 (Flt-1) and kinase-domain insert containing receptor (KDR) were determined in participants' leucocytes with RT-PCR. Apoptosis rates as well as Cyt-C and Caspase-3 expression was determined in Jurkat, Jurkat(Bcl-2), healthy and recurrent leukemia leukocytes with and without VP-16 applications via flow cytometry. Total Akt (t-Akt) expression and its phosphorylation (p-AKT) status in leukocytes of the participants were analyzed with western blots.
  
  
  RESULTS
  Healthy children and the remission group had the lowest blood plasma VEGF concentrations (91.16±41.34 vs. 135.80±111.28 pg/ml), followed by de novo leukemia patients (362.49±195.68 pg/ml-494.19±186.23 pg/ml) and relapse patients (574.37±278.45 pg/ml) (P<0.01). The same trend was statistically significant visible for Flt-1 and KDR expressions in leukocytes of the participants. Stable Bcl-2 overexpression led to reduced apoptosis rates as well as Cyt-C and Caspase-3 expressions in Jurkat cells after VP-16 application, which was similar in leucocytes of remission patients. In contrast to no phosphorylation in healthy children, Akt was phosphorylated in 10% remission samples, 30% de novo leukemia samples and in 67% of recurrent leukemia leucocytes.
  
  
  CONCLUSIONS
  High VEGF plus VEGFR expression and AKT phosphorylation are highest in leukocytes of remission patients, suggesting VEGF signaling as a cause of reduced apoptosis susceptibility upon treatments.
authors.affiliation: Department of Hematology, Shanghai Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine 639 Zhizaoju Road, Shanghai 200011, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Hematology, Tongji Hospital of Tongji University 389 Xincun Road, Shanghai 200065, China.
authors.forename: Wenjun
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Department of Hematology, Tongji Hospital of Tongji University 389 Xincun Road, Shanghai 200065, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Ding
authors.affiliation: Department of Hematology, Tongji Hospital of Tongji University 389 Xincun Road, Shanghai 200065, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Xiu
authors.affiliation: Department of Hematology, Tongji Hospital of Tongji University 389 Xincun Road, Shanghai 200065, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Li
authors.affiliation: Department of Hematology, Tongji Hospital of Tongji University 389 Xincun Road, Shanghai 200065, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Dong
authors.affiliation: Department of Hematology, Shanghai Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine 639 Zhizaoju Road, Shanghai 200011, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhu
authors.affiliation: Department of Hematology, Tongji Hospital of Tongji University 389 Xincun Road, Shanghai 200065, China.
authors.forename: Aibin
authors.initials: A
authors.lastname: Liang
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects; D014408:Biomarkers, Tumor / Q000097:blood / Q000235:genetics; D016022:Case-Control Studies; D053148:Caspase 3 / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D045304:Cytochromes c / Q000378:metabolism; D019008:Drug Resistance, Neoplasm; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D018922:HL-60 Cells; D006801:Humans; D007223:Infant; D019169:Jurkat Cells; D020014:K562 Cells; D007938:Leukemia / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy* / Q000235:genetics; D007962:Leukocytes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008297:Male; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D012074:Remission Induction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016896:Treatment Outcome; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A / Q000097:blood*; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000235:genetics*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000235:genetics*
chemical_list: C000595707:BCL2 protein, human; D014408:Biomarkers, Tumor; D019253:Proto-Oncogene Proteins c-bcl-2; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D045304:Cytochromes c; C501162:FLT1 protein, human; D040281:Vascular Endothelial Growth Factor Receptor-1; D040301:Vascular Endothelial Growth Factor Receptor-2; D051057:Proto-Oncogene Proteins c-akt; C505407:CASP3 protein, human; D053148:Caspase 3
keywords: Flt-1; KDR; PI3K/AKT; VEGF; apoptosis; leukemia