Search tips
Search criteria

Results 1-7 (7)

Clipboard (0)

Select a Filter Below

Year of Publication
Document Types
1.  Reproductive Effects in F1 Adult Females Exposed In Utero to Moderate to High Doses of Mono-2-ethylhexylphthalate (MEHP) 
Phthalates are widely used as plasticizers in everyday products. Yet, studies on the effects of phthalates on female reproductive health are limited. In this study, pregnant C57/Bl6 mice were exposed via oral gavage to corn oil, 100, 500, or 1000mg/kg MEHP from gestational days 17–19. Reproductive lifespan was decreased by one month in the highest F1 exposure group (9.8±0.4 versus 11.1±0.6 months in control F1 females). F1 females exhibited delayed estrous onset at the two higher exposures and prolonged estrus was observed in all MEHP-exposed females. Serum FSH and estradiol were significantly elevated at the highest exposure and altered mRNA expression was found for the steroidogenic genes LHCGR, aromatase, and StAR. At one year of age, mammary gland hyperplasia was observed in high dose MEHP-exposed females. In summary, late gestational exposure to MEHP leads to multiple latent reproductive effects throughout murine life resulting in premature ovarian senescence and mammary hyperplasia.
PMCID: PMC3367132  PMID: 22401849
MEHP; ovary; premature ovarian failure; steroidogenesis
2.  Preliminary Efficacy of the Anti-Insulin–Like Growth Factor Type 1 Receptor Antibody Figitumumab in Patients With Refractory Ewing Sarcoma 
Journal of Clinical Oncology  2011;29(34):4534-4540.
Patients with Ewing sarcoma (ES) with metastases and those who relapse fare poorly and receive therapies that carry significant toxicity. This phase 1/2 study was conducted to evaluate the efficacy of figitumumab in advanced ES.
Patients and Methods
Patients with sarcoma 10 to 18 years old were enrolled in two dose escalation cohorts (20 and 30 mg/Kg intravenously every 4 weeks) in the phase 1 portion of the study. Patients with ES 10 years old or older were enrolled in the phase 2 portion of the study. The primary phase 2 objective was objective response rate (ORR).
Thirty-one patients with ES (n = 16), osteosarcoma (n = 11), or other sarcomas (n = 4) were enrolled in the phase 1 portion of the study. Dose escalation proceeded to 30 mg/kg every 4 weeks with no dose-limiting toxicity identified. In the phase 2 portion of the study, 107 patients with ES received figitumumab at 30 mg/kg every 4 weeks for a median of 2 cycles (range, 1 to 16). Sixty three percent of phase 2 patients had received at least three prior treatment regimens. Of 106 evaluable patients, 15 had a partial response (ORR, 14.2%) and 25 had stable disease. Median overall survival was 8.9 months. Importantly, patients with a pretreatment circulating free insulin-like growth factor (IGF) -1 lower than 0.65 ng/mL (n = 14) had a median OS of 3.6 months, whereas those with a baseline free IGF-1 ≥ 0.65 ng/mL (n = 84) had a median OS of 10.4 months (P < .001).
Figitumumab had modest activity as single agent in advanced ES. A strong association between pretreatment serum IGF-1 and survival benefit was identified.
PMCID: PMC3236653  PMID: 22025154
3.  Akt1 protects against germ cell apoptosis in the postnatal mouse testis following lactational exposure to 6-N-propylthiouracil 
Exposure to 6-propyl-2-thio-uracil (PTU), a neonatal goitrogen, leads to increased testis size and sperm production in rodents. Akt1, a gene involved in cell survival and proliferation is also phosphorylated by thyroxine (T4). Therefore, we examined the requirement for Akt1 in germ cell survival following PTU-induced hypothyroidism. Experiments were performed using Akt1+/+, Akt1+/−, and Akt1−/− mice. PTU was administered (0.01% w/v) via the drinking water of dams from birth to PND21. At PND15, T4 serum levels were similar in all control groups, and significantly lower in all exposed groups with a dramatic decrease in Akt1−/− mice. PTU-exposed Akt1−/− testes displayed smaller tubules, increased apoptosis, delayed lumen formation, and increased inhibin B and AMH mRNA. Relative adult testis weights were similar in all exposure groups; however, no increase in daily sperm production was observed in PTU-exposed Akt1−/− mice. In conclusion, Akt1 contributes to the effects of thyroid hormone on postnatal testis development.
PMCID: PMC3033462  PMID: 20951798
Akt1; Sertoli cell; germ cell; transient postnatal hypothyroidism; propylthiouracil
4.  Molecular Analysis of Non-Small Cell Lung Cancer (NSCLC) Identifies Subsets with Different Sensitivity to Insulin like Growth Factor I Receptor (IGF-IR) Inhibition 
Identify molecular determinants of sensitivity of NSCLC to anti-insulin like growth factor receptor (IGF-IR) therapy.
Experimental Design
216 tumor samples were investigated. 165 consisted of retrospective analyses of banked tissue and an additional 51 were from patients enrolled in a phase 2 study of figitumumab (F), a monoclonal antibody against the IGF-IR, in stage IIIb/IV NSCLC. Biomarkers assessed included IGF-IR, EGFR, IGF-2, IGF-2R, IRS-1, IRS-2, vimentin and E-cadherin. Sub-cellular localization of IRS-1 and phosphorylation levels of MAPK and Akt1 were also analyzed.
IGF-IR was differentially expressed across histological subtypes (P=0.04), with highest levels observed in squamous cell tumors. Elevated IGF-IR expression was also observed in a small number of squamous cell tumors responding to chemotherapy combined with F (p=0.008). Since no other biomarker/response interaction was observed using classical histological sub-typing, a molecular approach was undertaken to segment NSCLC into mechanism-based subpopulations. Principal component analysis and unsupervised Bayesian clustering identified 3 NSCLC subsets that resembled the steps of the epithelial-to-mesenchymal transition: E-cadherin high/IRS-1 low (Epithelial-like), E-cadherin intermediate/IRS-1 high (Transitional) and E-cadherin low/IRS-1 low (Mesenchymal-like). Several markers of the IGF-IR pathway were over-expressed in the Transitional subset. Furthermore, a higher response rate to the combination of chemotherapy and F was observed in Transitional tumors (71%) compared to those in the Mesenchymal-like subset (32%, p=0.03). Only one Epithelial-like tumor was identified in the phase 2 study, suggesting that advanced NSCLC has undergone significant de-differentiation at diagnosis.
NSCLC comprises molecular subsets with differential sensitivity to IGF-IR inhibition.
PMCID: PMC2952544  PMID: 20670944
IGF-IR; Figitumumab; NSCLC
5.  Safety, Pharmacokinetics, and Pharmacodynamics of the Insulin-Like Growth Factor Type 1 Receptor Inhibitor Figitumumab (CP-751,871) in Combination with Paclitaxel and Carboplatin 
This phase 1 study was conducted to determine the recommended phase 2 dose of the selective insulin-like growth factor type 1 receptor (IGF-IR) inhibitor figitumumab (F, CP-751,871) given in combination with paclitaxel and carboplatin in patients with advanced solid tumors.
Patients received paclitaxel 200 mg/m2, carboplatin (area under the curve of 6), and F (0.05–20 mg/kg) q3 weeks for up to six cycles. Patients with objective response or stable disease were eligible to receive additional cycles of single agent F until disease progression. Safety, efficacy, pharmacokinetic, and pharmacodynamic endpoints were investigated.
Forty-two patients, including 35 with stages IIIB and IV non-small cell lung cancer (NSCLC), were enrolled in eight dose escalation cohorts. A maximum tolerated dose was not identified. Severe adverse events possibly related to F included fatigue, diarrhea, hyperglycemia, gamma glutamyl transpeptidase elevation, and thrombocytopenia (one case each). F plasma exposure parameters increased with dose. Fifteen objective responses (RECIST) were reported, including two complete responses in NSCLC and ovarian carcinoma. Notably, levels of bioactive IGF-1 seemed to influence response to treatment with objective responses in patients with a high baseline-free IGF-1 to IGF binding protein-3 ratio seen only in the 10 and 20 mg/kg dosing cohorts.
F was well tolerated in combination with paclitaxel and carboplatin. Based on its favorable safety, pharmacokinetic, and pharmacodynamic properties, the maximal feasible dose of 20 mg/kg has been selected for further investigation.
PMCID: PMC2941876  PMID: 19745765
IGF-1R; Figitumumab; CP-751,871; NSCLC
6.  Akt1/PKB upregulation leads to vascular smooth muscle cell hypertrophy and polyploidization 
Journal of Clinical Investigation  2000;106(8):1011-1020.
Vascular smooth muscle cells (VSMCs) at capacitance arteries of hypertensive individuals and animals undergo marked age- and blood pressure–dependent polyploidization and hypertrophy. We show here that VSMCs at capacitance arteries of rat models of hypertension display high levels of Akt1/PKB protein and activity. Gene transfer of Akt1 to VSMCs isolated from a normotensive rat strain was sufficient to abrogate the activity of the mitotic spindle cell–cycle checkpoint, promoting polyploidization and hypertrophy. Furthermore, the hypertrophic agent angiotensin II induced VSMC polyploidization in an Akt1-dependent manner. These results demonstrate that Akt1 regulates ploidy levels in VSMCs and contributes to vascular smooth muscle polyploidization and hypertrophy during hypertension.
PMCID: PMC314338  PMID: 11032861
7.  Ectopic Expression of cdc2/cdc28 Kinase Subunit Homo sapiens 1 Uncouples Cyclin B Metabolism from the Mitotic Spindle Cell Cycle Checkpoint 
Molecular and Cellular Biology  1998;18(11):6224-6237.
Primary human fibroblasts arrest growth in response to the inhibition of mitosis by mitotic spindle-depolymerizing drugs. We show that the mechanism of mitotic arrest is transient and implicates a decrease in the expression of cdc2/cdc28 kinase subunit Homo sapiens 1 (CKsHs1) and a delay in the metabolism of cyclin B. Primary human fibroblasts infected with a retroviral vector that drives the expression of a mutant p53 protein failed to downregulate CKsHs1 expression, degraded cyclin B despite the absence of chromosomal segregation, and underwent DNA endoreduplication. In addition, ectopic expression of CKsHs1 interfered with the control of cyclin B metabolism by the mitotic spindle cell cycle checkpoint and resulted in a higher tendency to undergo DNA endoreduplication. These results demonstrate that an altered regulation of CKsHs1 and cyclin B in cells that carry mutant p53 undermines the mitotic spindle cell cycle checkpoint and facilitates the development of aneuploidy. These data may contribute to the understanding of the origin of heteroploidy in mutant p53 cells.
PMCID: PMC109209  PMID: 9774639

Results 1-7 (7)