Reverse translation of phase I biomarker findings links the activity of angiotensin-(1-7) to repression of hypoxia inducible factor-1α in vascular sarcomas.

BACKGROUND: In a phase I study of angiotensin-(1-7) [Ang-(1-7)], clinical benefit was associated with reduction in plasma placental growth factor (PlGF) concentrations. The current study examines Ang-(1-7) induced changes in biomarkers according to cancer type and investigates mechanisms of action engaged in vitro. METHODS: Plasma biomarkers were measured prior to Ang-(1-7) administration as well as 1, 2, 3, 4, and 6 hours after treatment. Tests for interaction were performed to determine the impact of cancer type on angiogenic hormone levels. If a positive interaction was detected, treatment-induced biomarker changes for individual cancer types were assessed. To investigate mechanisms of action, in vitro growth assays were performed using a murine endothelioma cell line (EOMA). PCR arrays were performed to identify and statistically validate genes that were altered by Ang-(1-7) treatment in these cells. RESULTS: Tests for interaction controlled for dose cohort and clinical response indicated a significant impact of cancer type on post-treatment VEGF and PlGF levels. Following treatment, PlGF levels decreased over time in patients with sarcoma (P = .007). Treatment of EOMA cells with increasing doses of Ang-(1-7) led to significant growth suppression at doses as low as 100 nM. PCR arrays identified 18 genes that appeared to have altered expression after Ang-(1-7) treatment. Replicate analyses confirmed significant changes in 8 genes including reduction in PlGF (P = .04) and hypoxia inducible factor 1α (HIF-1α) expression (P < .001). CONCLUSIONS: Ang-(1-7) has clinical and pre-clinical activity for vascular sarcomas that is linked to reduced HIF-1α and PlGF expression.

High cyclin D3 expression confers erlotinib resistance in aerodigestive tract cancer.

BACKGROUND: Prior studies highlighted cyclin D1 as a key biomarker of response to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors. This study builds on prior work by examining the roles of cyclin D1, cyclin D3, and cyclin E in mediating erlotinib sensitivity or resistance. METHODS: Expression plasmids for G1 cyclins were independently transfected into NIH 3T3 cells and effects on erlotinib sensitivity were examined. The expression profiles of G1 cyclins were compared in erlotinib-sensitive and erlotinib-resistant lung cancer cell lines. A549 and H358 cells were treated with erlotinib and changes in cyclin protein expression were assessed. Cyclin D3 immunohistochemical staining was measured in biopsy tissues obtained from patients before and after treatment with erlotinib. Erlotinib-sensitive lung cancer cells were transfected with cyclin D3 and changes in erlotinib sensitivity were examined. RESULTS: Individual transfection of cyclin D1, cyclin D3, and cyclin E expression plasmids each significantly reduced erlotinib sensitivity in NIH-3T3 cells. The erlotinib-resistant A549 cell line expressed high basal levels of cyclin D3 mRNA and protein. Comparison of tumor biopsies obtained from patients before and after treatment with erlotinib indicated an increase in the percentage of cancer cells expressing cyclin D3 following treatment with erlotinib (P=.02). Transfection of cyclin D3 into an erlotinib-sensitive lung cancer cell line inhibited erlotinib-induced signaling changes and reduced the growth-suppressive effects of erlotinib. CONCLUSIONS: High expression of cyclin D3 confers resistance to erlotinib in vitro and in vivo. Cyclin D3 immunohistochemical staining warrants investigation as a biomarker for predicting erlotinib resistance.