A first-in-class, first-in-human, phase I trial of p28, a non-HDM2-mediated peptide inhibitor of p53 ubiquitination in patients with advanced solid tumours.

BACKGROUND: This first-in-human, phase I clinical trial of p28 (NSC745104), a 28-amino-acid fragment of the cupredoxin azurin, investigated the safety, tolerability, pharmacokinetics and preliminary activity of p28 in patients with p53(+) metastatic solid tumours. METHODS: A total of 15 patients were administered p28 i.v. as a short infusion three times per week for 4 weeks followed by a 2-week rest under an accelerated titration 3+3 dose escalation design until either a grade 3-related adverse event occurred or the maximum tolerated dose (MTD) was reached. Single-dose and steady-state serum pharmacokinetics were characterised. Assessments included toxicity, best objective response by RECIST 1.1 Criteria, and overall survival. RESULTS: No patients exhibited any dose-limiting toxicities (DLTs), significant adverse events or exhibited an immune response (IgG) to the peptide. The No Observed Adverse Effect Level (NOAEL) and MTD were not reached. Seven patients demonstrated stable disease for 7-61 weeks, three a partial response for 44-125 weeks, and one a complete response for 139 weeks. Three patients are still alive at 158, 140, and 110 weeks post therapy completion. CONCLUSION: p28 was tolerated with no significant adverse events. An MTD was not reached. Evidence of anti-tumour activity indicates a highly favourable therapeutic index and demonstrates proof of concept for this new class of non-HDM2-mediated peptide inhibitors of p53 ubiquitination.

Prognostic significance of periodic acid-Schiff-positive patterns in primary cutaneous melanoma.

The patterns of periodic acid-Schiff (PAS) staining of extracellular matrix in histological sections of certain melanomas may be predictive of outcome. Recent in vitro and molecular genetic data suggest that the appearance of these patterns in both uveal and cutaneous melanoma is a function of aggressive tumor cells. We studied 96 patients with primary cutaneous melanomas treated at the University of Illinois at Chicago who were monitored for disease-free survival. Survival probabilities were determined by Kaplan-Meier estimates, and prognostic factors were evaluated by multivariate analysis. By univariate analysis, there was a significant decrease in disease-free survival among patients whose tumors contained parallel with cross-linking or network patterns (PXNs; P = 0.0070). Stepwise regression with Cox models that included the combinations of the PAS-positive patterns, tumor thickness, female gender, ulceration, and age yielded a model with thickness and the PAS-positive parallel with cross-linking or networks. Despite the relatively small sample size in this study, the detection of the PAS-positive parallel with cross-linking or networking in cutaneous melanoma was associated with a decrease in disease-free outcome. Additional studies of the prognostic significance of these patterns is warranted on larger data sets.

Overexpression of mutant p53 and c-erbB-2 proteins and breast tumour take in mice.

We established a panel of 17 xenografts from primary human breast carcinomas. We examined which characteristics of the original tumours and the xenografts facilitate growth in animals. Tumours expressing medium or strong immunoreactivity for p53 protein had significantly (P < 0.05) higher incidence (92%) of in vivo tumour take than those showing weak or negative immunoreactivity (9.1%). No such association was observed between either c-erbB-2 or epidermal growth factor receptor (EGFR) expression in the original tumours and their in vivo tumour take. Following subcutaneous (s.c.) transplantation of original breast tumours or established xenografts, 7/17 tumours showed metastatic disease spread to distant sites (mainly lungs). This study suggests that selective growth of highly aggressive tumours occurs during in vivo propagation of malignant tumours, and these tumours will be of particular interest in evaluating various chemotherapeutic agents for breast cancer management.

A cell line derived from a clinically benign phyllodes tumor: characterization and implications.

Phyllodes are uncommon tumors of the breast. Improved understanding of their behavior is hampered by the paucity of good laboratory models. We have developed two cell lines, by both xenograft and direct cell culture, derived from a histologically benign phyllodes tumor. Both cell lines have the same characteristics and growth kinetics. They grow as monolayers of spindle-shaped cells, with surface markers consistent with a mesenchymal origin. They do not express either estrogen or progesterone receptors. The cells have a relatively short doubling time of just over 1.5 days, and show a stimulatory effect with the addition of insulin. Karyotype analysis reveals the absence of one X chromosome.

Forequarter amputation for soft tissue tumors.

Forequarter amputation is a radical surgical procedure initially described for the treatment of traumatic injuries in 1908. This procedure has been used more recently in the treatment of soft tissue tumors. This report describes the experience in the Division of Surgical Oncology at the University of Illinois over a 20-year period. Between 1970 and 1991, 10 patients underwent forequarter amputations for malignant disease. Nine of these patients had soft tissue tumors and one a malignant melanoma. Four patients underwent amputation as primary treatment of their tumor, and six underwent the procedure as treatment for recurrent tumor. All patients are presently alive with a mean follow-up of more than 10 years. Three patients had recurrent tumor after the forequarter amputation. One local failure was salvaged with a chest wall resection, and two patients had distant failure. Forequarter amputation remains an effective procedure for local control of tumors of varying histology involving the shoulder girdle and upper arm. The most common indication for this procedure is a recurrent soft tissue tumor for which limb sparing procedures are not applicable. Forequarter amputation should remain a rarely used, but important, surgical option for the treatment of patients with soft tissue tumors.

Melanoma recurrence in a previously dissected lymph node basin.

OBJECTIVES: To retrospectively assess whether completeness of node dissection has any bearing on regional control in cutaneous melanoma and to examine the efficacy of a subsequent dissection in patients with isolated nodal recurrence. DESIGN: Case series, 18-month minimum follow-up. SETTING: Academic surgical practice. STUDY PARTICIPANTS: Patients with cutaneous melanoma who had undergone a regional node dissection and subsequently developed recurrence in the same nodal basin in which a lymphadenectomy had been performed with no evidence of distant metastases. Of 1030 instances of regional node dissection, 28 met these criteria. MAIN OUTCOME MEASURES: Nodal recurrence in the previously dissected lymph node basin as the only site of recurrence and survival following a subsequent lymph node dissection. RESULTS: The 28 instances of isolated nodal recurrence represent a regional failure rate of 2.7%. In those cases where the first dissection was performed within our division, the rate is 0.8%. Recurrence for cervical, axillary, or inguinal sites was similar. In 71% of the cases, more than one node was positive at the time of recurrence. Four patients have shown disease-free survival greater than 3 years following a subsequent lymphadenectomy. CONCLUSION: Node dissection is a therapeutic procedure and, therefore, must consist of complete lymphadenectomy with meticulous attention to surgical detail. Approached in this fashion, only a small subgroup of patients will show recurrence in a previously dissected nodal basin, a few of whom can be salvaged by a second dissection.

Selective microdetermination of lipid hydroperoxides.

A sensitive and selective assay for lipid hydroperoxides was developed based upon the activation by hydroperoxides of the cyclooxygenase activity of prostaglandin H synthase. The assay measures hydroperoxides directly by their stimulatory action on the cyclooxygenase and thus differs from the methods used currently which rely on the measurement of secondary products to estimate the amount of hydroperoxide. The present assay of enzymatic response was approximately linear in the range 10 to 150 pmol of added lipid hydroperoxide. This sensitivity for lipid peroxides is about 50-fold greater than that of the thiobarbiturate assay with fluorescence detection. When applied to samples of human plasma, the enzymatic assay indicated that the concentration of lipid hydroperoxides in normal subjects is 0.5 microM, more than 50-fold lower than estimated by the thiobarbiturate assay (30-50 microM). Nevertheless, the circulating concentration of 0.5 microM lipid hydroperoxide approaches that reported to have deleterious effects upon vascular prostacyclin synthase.

Presence of lipid hydroperoxide in human plasma.

Using purified prostaglandin (PG) H synthase, which synthesizes PGG2 and PGH2 from arachidonic acid, we were able to assay for the presence of peroxide activators in biological tissues. This assay system, capable of detecting both hydrogen peroxide (H2O2) and lipid hydroperoxides, detected a significant amount of synthase activator in plasma. Treatment of the active preparations with catalase and glutathione peroxidase showed that the principal activator in normal human plasma was a lipid hydroperoxide rather than H2O2.

Pathophysiologic modulation of arachidonate metabolism.

Low concentrations of lipid hydroperoxides are necessary to activate the biosynthesis of prostaglandins and other autacoids from arachidonate. When the concentration is too low (less than 10(-9) M) that biosynthesis is suppressed. However, lipid peroxides at concentrations higher than micromolar can inactivate prostacyclin synthase and, at higher levels, even prostaglandin H synthase. Thus, lipid hydroperoxides may be important regulators of biological processes, and their reliable quantitation is important in interpreting the physiologic status of a tissue. The plasma levels of lipid hydroperoxide that are indicated by the thiobarbituric acid (TBA) assay of normal human plasma (26-63 microM) would be high enough to totally inactivate prostacyclin synthase and thus they seem incompatible with a healthy vascular system. To resolve this paradox, we have developed a new assay which directly measures the level of lipid hydroperoxide. Controlled studies showed that the TBA-positive response of normal human plasma gave values for hydroperoxide that had no clear relationship to the actual level of hydroperoxide that was present and were 50-100 times greater than the directly observed values. The new direct assay indicates that the normal level of plasma lipid hydroperoxide may be approximately 0.5 microM. Such a level may provide chronic stress on the ability of vascular endothelial cells to provide sufficient amounts of the antithrombotic autacoid, prostacyclin. Our results indicate that relatively slight elevations from the normal circulating hydroperoxide levels might be expected to have undesirable effects, and that a reliable monitoring of plasma hydroperoxide levels may be useful.