ABSTRACT
BACKGROUND: The Insulin-like growth factor (IGF) pathway plays a role in tumour development and progression. In vivo, IGF1 activity is regulated by the IGF binding proteins (IGFBPs). IGFBP4 inhibits the activity of IGF1 but proteolytic cleavage by pregnancy-associated plasma protein-A (PAPP-A) releases active IGF1. A modified IGFBP4, dBP4, which was resistant to PAPP-A cleavage but retained IGF1 binding capacity, was engineered, expressed in Human Embryonic Kidney (HEK) 293 cells and purified. This study examined the effects of dBP4 on IGF1-induced cell migration, invasion and angiogenesis in vitro. The effect of intra-tumour injections of dBP4 on tumour angiogenesis and metastasis was examined using the 4T1.2luc orthotopic model of breast cancer. METHODS: PAPP-A resistance and IGF binding capacity of dBP4 were characterized by Western blot and surface plasmon resonance, respectively. 4T1.2luc are mouse mammary adenocarcinoma cells transfected with luciferase to allow in vivo imaging. The effect of dBP4 on IGF1-induced Akt activation in 4T1.2luc cells was assessed by Western blot. Cell migration and invasion assays were performed using 4T1.2luc cells. Angiokit™ assays and Matrigel® implants were used to assess the effects of dBP4 on angiogenesis in vitro and in vivo, respectively. An orthotopic breast cancer model - 4T1.2luc cells implanted in the mammary fat pad of BALB/c mice - was used to assess the effect of intra tumour injection of purified dBP4 on tumour angiogenesis and metastasis. Tumour growth and lung metastasis were examined by in vivo imaging and tumour angiogenesis was evaluated by CD31 immunohistochemistry. RESULTS: Our engineered, PAPP-A resistant IGFBP4 (dBP4) retained IGF1 binding capacity and inhibited IGF1 activation of Akt as well as IGF1-induced migration and invasion by 4T1.2 mammary adenocarcinoma cells. dBP4 inhibited IGF1-induced angiogenesis in vitro and in Matrigel implants in vivo. Direct intra-tumour injection of soluble dBP4 reduced angiogenesis in 4T1.2 luc mammary tumours tumour and reduced lung metastasis. CONCLUSION: A PAPP-A resistant IGFBP4, dBP4, inhibits angiogenesis and metastasis in 4T1.2 mammary fat pad tumours. This study highlights the therapeutic potential of dBP4 as an approach to block the tumour-promoting actions of IGF1.
Subject(s)
Breast Neoplasms/metabolism , Breast Neoplasms/pathology , Insulin-Like Growth Factor Binding Protein 4/metabolism , Neovascularization, Pathologic/metabolism , Pregnancy-Associated Plasma Protein-A/metabolism , Animals , Cell Line, Tumor , Cell Movement/genetics , Disease Models, Animal , Female , Humans , Immunohistochemistry , Insulin-Like Growth Factor I/metabolism , Mice , Neoplasm Metastasis , Phosphorylation , Proteolysis , Proto-Oncogene Proteins c-akt/metabolism , Recombinant ProteinsSubject(s)
Anticonvulsants/administration & dosage , Child Psychiatry , Psychiatric Department, Hospital , Psychotropic Drugs/administration & dosage , Adolescent , Child , Child, Preschool , Denmark , Drug Utilization , Female , Humans , Infant , Infant, Newborn , Male , Referral and Consultation , Retrospective StudiesSubject(s)
Digestive System/diagnostic imaging , Foreign Bodies/epidemiology , Adolescent , Adult , Denmark , Female , Humans , Male , Middle Aged , Opioid-Related Disorders , Prisoners , Radiography , Retrospective StudiesABSTRACT
The prognostic value of plasma prekallikrein activity, prothrombin time, and serum albumin with regard to survival in chronic liver insufficiency was evaluated in 21 consecutive patients. Twenty patients had liver cirrhosis, and one patient had malignant liver disease (hepatocellular carcinoma). Eight patients died between 4 and 43 days after the time of blood sampling. These patients had a prekallikrein value less than 0.42. There were no overlapping prekallikrein values between patients who died and patients who survived (overlap index 0; p less than 0.001). Overlap index for prothrombin time was 0.35 (p less than 0.02), and for serum albumin 0.34 (p less than 0.02). In conclusion, plasma prekallikrein seems to indicate whether death is imminent in patients with liver insufficiency due to cirrhosis. Longitudinal studies of prekallikrein activity in different subgroups of patients with chronic and acute liver disease are recommended.