Feasibility of using interpolated contours of targets and organs at risk in intensity‐modulated radiation therapy treatment planning for advanced‐stage nasopharyngeal carcinoma

To assess the dosimetric effect of using interpolated contours in planning intensity‐modulated radiation therapy (IMRT) for advanced T‐stage nasopharyngeal carcinoma. The present study focused on T3–T4 tumours where the proximity of targets to neurological organs poses a stringent test on the feasibility of such an approach. Contours of targets and organs were delineated on CT images of 2.5‐mm interval and a reference IMRT plan was generated. An investigative (INV) IMRT plan was then generated with the same planning protocol, but based on interpolated contours that replaced deleted contours on alternate slices. The reference and INV plans were compared. Regarding target coverage, all targets in the INV plans met the acceptance criteria except for the PTV in one case. Regarding organs, the mean dose to 1% volume of the brainstem and spinal cord in the INV plans were kept below their dose limits. No significant differences in the mean doses to others organs were found. Satisfactory target coverage and protection of critical organs to a degree similar to full‐scale contouring could be achieved with use of interpolated contours. The saving in manpower time for contouring is expected to significantly improve the throughput of the IMRT planning process.     

Phase I dose escalation study of the anti insulin-like growth factor-I receptor monoclonal antibody CP-751,871 in patients with refractory solid tumors.

PURPOSE: This phase I study was undertaken to define the maximum tolerated dose, safety, and pharmacokinetic profile of CP-751,871. EXPERIMENTAL DESIGN: Using a rapid dose escalation design, patients with advanced nonhematologic malignancies were treated with CP-751,871 in four dose escalation cohorts. CP-751,871 was administered i.v. on day 1 of each 21-day cycle. Pharmacokinetic evaluation was done in all treatment cohorts during cycles 1 and 4. RESULTS: Twenty-four patients received 110 cycles at four dose levels. The maximum tolerated dose exceeded the maximal feasible dose of 20 mg/kg and, thus, was not identified. Treatment-related toxicities were generally mild. The most common adverse events were hyperglycemia, anorexia, nausea, elevated aspartate aminotransferase, elevated gamma-glutamyltransferase, diarrhea, hyperuracemia, and fatigue. At 20 mg/kg, 10 of 15 patients experienced stability of disease. Two of these patients experienced long-term stability. There were no objective responses. Pharmacokinetic analysis revealed a dose-dependent increase in CP-751,871 exposure and approximately 2-fold accumulation on repeated dosing in 21-day cycles. Plasma concentrations of CP-751,871 attained were several log-fold greater than the biologically active concentration. Treatment with CP-751,871 increased serum insulin and human growth hormone levels, with modest increases in serum glucose levels. CONCLUSIONS: CP-751,871 has a favorable safety profile and was well tolerated when given in continuous cycles. At the maximal feasible dose of 20 mg/kg, there was a moderate accumulation in plasma exposure, and most of the treated patients experienced stability of disease.     

Abrogation of MAPK and Akt signaling by AEE788 synergistically potentiates histone deacetylase inhibitor-induced apoptosis through reactive oxygen species generation.

PURPOSE: To evaluate the effects of combining the multiple receptor tyrosine kinase inhibitor AEE788 and histone deacetylase (HDAC) inhibitors on cytotoxicity in a broad spectrum of cancer cell lines, including cisplatin-resistant ovarian adenocarcinoma cells. EXPERIMENTAL DESIGN: Multiple cancer cell lines were treated in vitro using AEE788 and HDAC inhibitors (LBH589, LAQ824, and trichostatin A), either alone or in combination. Effects on cytotoxicity were determined by growth and morphologic assays. Effects of the combination on cell signaling pathways were determined by Western blotting, and the results were confirmed using pathway-specific inhibitors and transfection of constitutively active proteins. RESULTS: Cell treatment with AEE788 and HDAC inhibitors (LBH589, LAQ824, and trichostatin A) in combination resulted in synergistic induction of apoptosis in non-small cell lung cancer (MV522, A549), ovarian cancer (SKOV-3), and leukemia (K562, Jurkat, and ML-1) cells and in OV202hp cisplatin-resistant human ovarian cancer cells. AEE788 alone or in combination with LBH589 inactivated mitogen-activated protein kinase (MAPK) and Akt cascades. Inhibition of either MAPK and/or Akt enhanced LBH589-induced apoptosis. In contrast, constitutively active MAPK or Akt attenuated LBH589 or LBH589 + AEE788-induced apoptosis. Increased apoptosis was correlated with enhanced reactive oxygen species (ROS) generation. The free radical scavenger N-acetyl-l-cysteine not only substantially suppressed the ROS accumulation but also blocked the induction of apoptosis mediated by cotreatment with AEE788 and LBH589. CONCLUSION: Collectively, these results show that MAPK and Akt inactivation along with ROS generation contribute to the synergistic cytotoxicity of the combination of AEE788 and HDAC inhibitors in a variety of human cancer cell types. This combination regimen warrants further preclinical and possible clinical study for a broad spectrum of cancers.     

Predicting clinical outcome in patients diagnosed with synchronous ovarian and endometrial cancer

PURPOSE: Patients with synchronous ovarian and endometrial cancers may represent cases of a single primary tumor with metastasis (SPM) or dual primary tumors (DP). The diagnosis given will influence the patient's treatment and prognosis. Currently, a diagnosis of SPM or DP is made using histologic criteria, which are frequently unable to make a definitive diagnosis. EXPERIMENTAL DESIGN: In this study, we used genetic profiling to make a genetic diagnosis of SPM or DP in 90 patients with synchronous ovarian/endometrial cancers. We compared genetic diagnoses in these patients with the original histologic diagnoses and evaluated the clinical outcome in this series of patients based on their diagnoses. RESULTS: Combining genetic and histologic approaches, we were able make a diagnosis in 88 of 90 cases, whereas histology alone was able to make a diagnosis in only 64 cases. Patients diagnosed with SPM had a significantly worse survival than patients with DP (P = 0.002). Patients in which both tumors were of endometrioid histology survived longer than patients of other histologic subtypes (P = 0.025), and patients diagnosed with SPM had a worse survival if the mode of spread was from ovary to endometrium rather than from endometrium to ovary (P = 0.019). CONCLUSIONS: Genetic analysis may represent a powerful tool for use in clinical practice for distinguishing between SPM and DP in patients with synchronous ovarian/endometrial cancer and predicting disease outcome. The data also suggest a hitherto uncharacterized level of heterogeneity in these cases, which, if accurately defined, could lead to improved treatment and survival.     

Activity of the Bcl-2 family inhibitor ABT-263 in a panel of small cell lung cancer xenograft models

PURPOSE: The purpose of this study was to characterize the activity of the Bcl-2 protein family inhibitor ABT-263 in a panel of small cell lung cancer (SCLC) xenograft models. EXPERIMENTAL DESIGN: A panel of 11 SCLC xenograft models was established to evaluate the efficacy of ABT-263. Single agent activity was examined on a continuous dosing schedule in each of these models. The H146 model was used to further evaluate dose and schedule, comparison to standard cytotoxic agents, and induction of apoptosis. RESULTS: ABT-263 exhibited a range of antitumor activity, leading to complete tumor regression in several models. Significant regressions of tumors as large as 1 cc were also observed. The efficacy of ABT-263 was also quite durable; in several cases, minimal tumor regrowth was noted several weeks after the cessation of treatment. Antitumor effects were equal or superior to that of several clinically approved cytotoxic agents. Regression of large established tumors was observed through several cycles of therapy and efficacy was retained in a Pgp-1 overexpressing line. Significant efficacy was observed on several dose and therapeutic schedules and was associated with significant induction of apoptosis. CONCLUSIONS: ABT-263 is a potent, orally bioavailable inhibitor of Bcl-2 family proteins that has recently entered clinical trials. The efficacy data reported here suggest that SCLC is a promising area of clinical investigation with this agent.     

Vaccination with a recombinant Saccharomyces cerevisiae expressing a tumor antigen breaks immune tolerance and elicits therapeutic antitumor responses

PURPOSE: Saccharomyces cerevisiae, a nonpathogenic yeast, has been used previously as a vehicle to elicit immune responses to foreign antigens, and tumor-associated antigens, and has been shown to reduce tumor burden in mice. Studies were designed to determine if vaccination of human carcinoembryonic antigen (CEA)-transgenic (CEA-Tg) mice (where CEA is a self-antigen) with a recombinant S. cerevisiae construct expressing human CEA (yeast-CEA) elicits CEA-specific T-cell responses and antitumor activity. EXPERIMENTAL DESIGN: CEA-Tg mice were vaccinated with yeast-CEA, and CD4(+) and CD8(+) T-cell responses were assessed after one and multiple administrations or vaccinations at multiple sites per administration. Antitumor activity was determined by tumor growth and overall survival in both pulmonary metastasis and s.c. pancreatic tumor models. RESULTS: These studies demonstrate that recombinant yeast can break tolerance and that (a) yeast-CEA constructs elicit both CEA-specific CD4(+) and CD8(+) T-cell responses; (b) repeated yeast-CEA administration causes increased antigen-specific T-cell responses after each vaccination; (c) vaccination with yeast-CEA at multiple sites induces a greater T-cell response than the same dose given at a single site; and (d) tumor-bearing mice vaccinated with yeast-CEA show a reduction in tumor burden and increased overall survival compared to mock-treated or control yeast-vaccinated mice in both pulmonary metastasis and s.c. pancreatic tumor models. CONCLUSIONS: Vaccination with a heat-killed recombinant yeast expressing the tumor-associated antigen CEA induces CEA-specific immune responses, reduces tumor burden, and extends overall survival in CEA-Tg mice. These studies thus form the rationale for the incorporation of recombinant yeast-CEA and other recombinant yeast constructs in cancer immunotherapy protocols.     

The Fetal Liver in Pizz Alpha-1-Antitrypsin Deficiency: a Report of Five Cases

The lack of information on the state of fetal liver in PiZZ alpha-1-antitrypsin (AAT) deficiency and a single case report claiming a hypoplasia of interlobular bile ducts in a 20-week PiZZ fetus, instigated this histologic study of the liver in five PiZZ fetuses, 17-20 weeks of gestation and five age-matched controls. We found no difference between the percentage of portal tracts with identifiable bile ducts in the PiZZ (median 22.2%, range 21%-23%) and in the control (median 21.4%, range 20%-24%) on hematoxylin- and eosin-stained sections. Immunostaining with AE1, a monoclonal antibody to cyto-keratins restricted to normal bile ducts, doubled the number of recognizable ducts in both PiZZ and control livers. In four PiZZ livers, but in none of the controls, granular deposits of AAT could be detected by specific immunoperoxidase staining. We conclude that an apparent paucity of interlobular bile ducts is normal in the 20-week fetal liver, and our data may be taken as reference for future study dealing with similar material. Except for the cytoplasmic deposition of granules immunoreactive to AAT antiserum, there was no evidence of any developmental anomaly, in particular of the bile duct system in these five PiZZ fetal livers.     

Retinoic acid nuclear receptors and tumor promotion: decreased expression of retinoic acid nuclear receptors by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate

During studies to determine the mechanism of tumor promotionby 12-O-tetradecanoylphorbol-13-acetate (TPA), we found thatTPA downregulates mouse epidermal retinoic acid nuclear receptors(RAR), a superfamily of nuclear steroid/thyrold receptors implicatedin mediating effects of retinoic acid (RA). Application of TPAto mouse skin decreased the binding of [³H]RA to RAR from mouseepidermal nuclear extracts. In this experiment, 20 nmol of TPAwas applied to mouse skin and 3.5 h later binding of [³H]RAto RAR was analyzed by chromatography on a size-exclusion column.TPA treatment resulted in an