A Multicenter, Phase 2 Study of Vascular Endothelial Growth Factor Trap (Aflibercept) in Platinum- and Erlotinib-Resistant Adenocarcinoma of the Lung

IntroductionAflibercept (vascular endothelial growth factor [VEGF] trap), a recombinant fusion protein, blocks the activity of VEGF-A and placental growth factor and has demonstrated activity in pretreated patients with lung cancer in a phase I trial. This study evaluated the efficacy and safety of intravenous aflibercept in patients with platinum- and erlotinib-resistant lung adenocarcinoma.MethodsAn open-label, single arm, multicenter trial was conducted, with the primary end point of response rate (modified RECIST). Additional endpoints included safety, duration of response, progression-free survival, and overall survival. Patients with platinum- and erlotinib-resistant lung adenocarcinoma were eligible. Aflibercept 4.0 mg/kg intravenous every 2 weeks was administered until progression of disease or intolerable toxicity.ResultsNinety-eight patients were enrolled; 89 were evaluable for response. Median age was 60 years, 41% were men with Eastern Cooperative Oncology Group performance status 0/1/2 in 35/55/9% of patients. The overall response rate was 2.0%, (95% confidence interval, 0.2-7.2%). Median progression-free survival was 2.7 months, and overall was survival 6.2 months. Six- and 12-month survival rates were 54 and 29%, respectively. A median of four cycles was administered (range 1-22). Common grade 3/4 toxicities included dyspnea (21%), hypertension (23%), and proteinuria (10%). Two cases of grade 5 hemoptysis were reported, and one case each of tracheoesophageal fistula, decreased cardiac ejection fraction, cerebral ischemia, and reversible posterior leukoencephalopathy.ConclusionsAflibercept has minor single agent activity in heavily pretreated lung adenocarcinoma, and is well tolerated, with no unexpected toxicities. Further studies evaluating aflibercept in lung cancer, in combination with chemotherapy and other targeted therapies, are ongoing

The Dyad Symmetry Element of Epstein-Barr Virus Is a Dominant but Dispensable Replication Origin

OriP, the latent origin of Epstein-Barr virus (EBV), consists of two essential elements: the dyad symmetry (DS) and the family of repeats (FR). The function of these elements has been predominantly analyzed in plasmids transfected into transformed cells. Here, we examined the molecular functions of DS in its native genomic context and at an ectopic position in the mini-EBV episome. Mini-EBV plasmids contain 41% of the EBV genome including all information required for the proliferation of human B cells. Both FR and DS function independently of their genomic context. We show that DS is the most active origin of replication present in the mini-EBV genome regardless of its location, and it is characterized by the binding of the origin recognition complex (ORC) allowing subsequent replication initiation. Surprisingly, the integrity of oriP is not required for the formation of the pre-replicative complex (pre-RC) at or near DS. In addition we show that initiation events occurring at sites other than the DS are also limited to once per cell cycle and that they are ORC-dependent. The deletion of DS increases initiation from alternative origins, which are normally used very infrequently in the mini-EBV genome. The sequence-independent distribution of ORC-binding, pre-RC-assembly, and initiation patterns indicates that a large number of silent origins are present in the mini-EBV genome. We conclude that, in mini-EBV genomes lacking the DS element, the absence of a strong ORC binding site results in an increase of ORC binding at dispersed sites

Negative autoregulation of c-myc gene expression is inactivated in transformed cells.

Negative feedback regulation of c-myc gene expression has been observed in some, but not all, cell types. In order to demonstrate conclusively the existence of this mechanism and gain insight into the cause of its inactivation, we have directly examined its function in B cells and then investigated its activity in a number of cell types. We demonstrate the existence of negative c-myc autoregulation by showing the rapid, dose dependent and reversible suppression of endogenous c-myc expression in EBV-immortalized B lymphoblastoid cells transfected with a c-myc gene expressed under the control of a heavy metal inducible promoter. Autoregulation occurs at the level of transcriptional initiation and is mediated by at least one stable intermediate or cofactor molecule. The c-myc autoregulatory mechanism was found operative in all (11 of 11) non-tumorigenic cells tested, including normal and immortalized lymphocytes and fibroblasts. However, this mechanism was found to be inactive in all (10 of 10) tumor cell lines derived from a variety of tissues including those carrying normal and oncogenically activated c-myc genes. These data establish the existence of an important regulatory circuit modulating c-myc expression in normal cells and suggest that its inactivation may represent a general regulatory disturbance of transformed cells