Citations

Abstract Purpose: A phase I, dose-finding study of vorinostat in combination with temozolomide (TMZ) was conducted to determine the maximum tolerated dose (MTD), safety, and pharmacokinetics in patients with high-grade glioma (HGG). Experimental Design: This phase I, dose-finding, investigational study was conducted in two parts. Part 1 was a dose-escalation study of vorinostat in combination with TMZ 150 mg/m2/day for 5 days every 28 days. Part 2 was a dose-escalation study of vorinostat in combination with TMZ 150 mg/m2/day for 5 days of the first cycle and 200 mg/m2/day for 5 days of the subsequent 28-day cycles. Results: In part 1, the MTD of vorinostat administered on days 1 to 7 and 15 to 21 of every 28-day cycle, in combination with TMZ, was 500 mg daily. Dose-limiting toxicities (DLT) included grade 3 anorexia, grade 3 ALT, and grade 5 hemorrhage in the setting of grade 4 thrombocytopenia. In part 2, the MTD of vorinostat on days 1 to 7 and 15 to 21 of every 28-day cycle, combined with TMZ, was 400 mg daily. No DLTs were encountered, but vorinostat dosing could not be escalated further due to thrombocytopenia. The most common serious adverse events were fatigue, lymphopenia, thrombocytopenia, and thromboembolic events. There were no apparent pharmacokinetic interactions between vorinostat and TMZ. Vorinostat treatment resulted in hyperacetylation of histones H3 and H4 in peripheral mononuclear cells. Conclusion: Vorinostat in combination with temozolomide is well tolerated in patients with HGG. A phase I/II trial of vorinostat with radiotherapy and concomitant TMZ in newly diagnosed glioblastoma is underway. Clin Cancer Res; 18(21); 6032–9. ©2012 AACR.

Abstract The Ras GTPase-activating-like protein IQGAP1 is a multimodular scaffold that controls signaling and cytoskeletal regulation in fibroblasts and epithelial cells. However, the functional role of IQGAP1 in T cell development, activation, and cytoskeletal regulation has not been investigated. In this study, we show that IQGAP1 is dispensable for thymocyte development as well as microtubule organizing center polarization and cytolytic function in CD8+ T cells. However, IQGAP1-deficient CD8+ T cells as well as Jurkat T cells suppressed for IQGAP1 were hyperresponsive, displaying increased IL-2 and IFN-γ production, heightened LCK activation, and augmented global phosphorylation kinetics after TCR ligation. In addition, IQGAP1-deficient T cells exhibited increased TCR-mediated F-actin assembly and amplified F-actin velocities during spreading. Moreover, we found that discrete regions of IQGAP1 regulated cellular activation and F-actin accumulation. Taken together, our data suggest that IQGAP1 acts as a dual negative regulator in T cells, limiting both TCR-mediated activation kinetics and F-actin dynamics via distinct mechanisms.

AbstractPurpose: To determine the response rate to oral capsular fenretinide in children with recurrent or biopsy proven refractory high-risk neuroblastoma.Experimental Design: Patients received 7 days of fenretinide: 2,475 mg/m2/d divided TID (<18 years) or 1,800 mg/m2/d divided BID (≥18 years) every 21 days for a maximum of 30 courses. Patients with stable or responding disease after course 30 could request additional compassionate courses. Best response by course 8 was evaluated in stratum 1 (measurable disease on CT/MRI ± bone marrow and/or MIBG avid sites) and stratum 2 (bone marrow and/or MIBG avid sites only).Results: Sixty-two eligible patients, median age 5 years (range 0.6–19.9), were treated in stratum 1 (n = 38) and stratum 2 (n = 24). One partial response (PR) was seen in stratum 2 (n = 24 evaluable). No responses were seen in stratum 1 (n = 35 evaluable). Prolonged stable disease (SD) was seen in 7 patients in stratum 1 and 6 patients in stratum 2 for 4 to 45+ (median 15) courses. Median time to progression was 40 days (range 17–506) for stratum 1 and 48 days (range 17–892) for stratum 2. Mean 4-HPR steady-state trough plasma concentrations were 7.25 μmol/L (coefficient of variation 40–56%) at day 7 course 1. Toxicities were mild and reversible.Conclusions: Although neither stratum met protocol criteria for efficacy, 1 PR + 13 prolonged SD occurred in 14/59 (24%) of evaluable patients. Low bioavailability may have limited fenretinide activity. Novel fenretinide formulations with improved bioavailability are currently in pediatric phase I studies. Clin Cancer Res; 17(21); 6858–66. ©2011 AACR.

Abnormal expression of genes for energy regulation in Parkinson’s disease patients identifies a master regulator as a possible therapeutic target for early intervention.