ABSTRACT
OBJECTIVES: Underlying mechanisms regulating angiogenesis in ovarian cancer have not been completely elucidated. Evidence suggests that the TP53 tumor suppressor pathway and tumor microenvironment play integral roles. We utilized microarray technology to study the interaction between TP53 mutational status and hypoxia on angiogenic gene expression. METHODS: Affymetrix U133A arrays were analyzed for angiogenic gene expression in 19 ovarian cancer cell lines stratified both by TP53 mutation status and A2780 wild-type (wt) TP53 vs. mutated (m) TP53 cell lines after treatment under hypoxic conditions or with ionizing radiation. RESULTS: Twenty-eight differentially expressed angiogenic genes were identified in the mTP53 cell lines compared to wtTP53 lines. Five genes were upregulated in mTP53 cells: 40% involved in extracellular matrix (ECM) degradation [matrix metalloproteinase 10 (MMP10)/15] and 60% in angiogenesis (fibroblast growth factor receptor 3/VEGFA/ephrin receptor-B4). Twenty-three genes were upregulated in wtTP53: nearly 22% were ECM constituents or involved in ECM degradation; over 40% were growth factors or mediators of angiogenesis. Five genes were upregulated in the A2780mTP53 cells: 40% involved in ECM remodeling (MMP10, ADAMTS1), 40% with pro-angiogenic activity (EFNB2, factor 2 receptor), and 20% with anti-angiogenic properties (ADAMTS1). Three genes were upregulated in hypoxia treated cells compared to controls: one with anti-angiogenic activity (angiopoietin-like 4) and two with pro-angiogenic activity (VEGFA, EFNA3). No significant gene fold changes were noted after exposure to radiation. Four genes continued to demonstrate significant differential expression (p ≤ 0.05) after adjusting for multiple comparisons. These genes included endoglin upregulation in wt lines (pro-angiogenesis) and upregulation of FGF20 (growth factor), ADAMTS1 (anti-angiogenesis) and MMP10 (ECM degradation) in mTP53 cell lines. CONCLUSION: Our exploratory findings indicate that non-overlapping angiogenic pathways may be altered by TP53 mutations and hypoxic conditions in the tumor microenvironment. Further evaluation is needed for confirmation.
ABSTRACT
PURPOSE: We conducted a phase I study of dasatinib, an oral SRC-family tyrosine kinase inhibitor, in combination with paclitaxel and carboplatin in the treatment of advanced and recurrent epithelial ovarian cancer. EXPERIMENTAL DESIGN: The primary objective was to determine the maximum tolerated dose (MTD). Secondary objectives included defining toxicity, response rate (RR), pharmacokinetics, and pharmacodynamics. Using a "3+3" design, cohorts of three to six patients received paclitaxel (175 mg/m(2)) and carboplatin (AUC 6) every 3 weeks with escalating doses of dasatinib (100, 120, and 150 mg daily), followed by an eight-patient expansion cohort. RESULTS: Twenty patients were enrolled between June 2007 and December 2009. The median age was 61 years (range: 42-82) with a median of 2 prior regimens (range: 0-6), and 71% had platinum-sensitive disease. There were three to six patients in each cohort, and eight in the expansion cohort. Pharmacokinetics were observed over the first two cycles of therapy. One DLT was observed in the 100 mg dasatinib cohort (grade 3 myalgia). Other toxicities in all cycles included neutropenia (95% grade 3-4; 91% in the 150 mg dosing cohort), thrombocytopenia (35% grade 3-4), and fatigue (10% grade 3). The RR was 40% [three complete responses, (15%); five partial responses, (25%)],10 patients (50%) had stable disease, and two were not evaluable. The PFS(6-month) actuarial estimate was 86%. The median PFS and OS were 7.8 and 16.2 months, respectively. CONCLUSIONS: Due to the high incidence of myelosuppression with subsequent cycles, the recommended phase II dose of dasatinib is 150 mg daily in combination with paclitaxel and carboplatin. The combination was safe with evidence of clinical activity.
