Second-line treatment of metastatic prostatic carcinoma

[64Cu-NOTA-8-Aoc-BBN(7-14)NH2] targeting vector for positron-emission tomography imaging of gastrin-releasing peptide receptor-expressing tissues

Radiolabeled peptides hold promise as diagnostic/therapeutic targeting vectors for specific human cancers. We report the design and development of a targeting vector, [(64)Cu-NOTA-8-Aoc-BBN(7-14)NH(2)] (NOTA = 1,4,7-triazacyclononane-1,4,7-triacetic acid, 8-Aoc = 8-aminooctanoic acid, and BBN = bombesin), having very high selectivity and affinity for the gastrin-releasing peptide receptor (GRPr). GRPrs are expressed on a variety of human cancers, including breast, lung, pancreatic, and prostate, making this a viable approach toward site-directed localization or therapy of these human diseases. In this study, [NOTA-X-BBN(7-14)NH(2)] conjugates were synthesized, where X = a specific pharmacokinetic modifier. The IC(50) of [NOTA-8-Aoc-BBN(7-14)NH(2)] was determined by a competitive displacement cell-binding assay in PC-3 human prostate cancer cells using (125)I-[Tyr(4)]-BBN as the displacement ligand. An IC(50) of 3.1 +/- 0.5 nM was obtained, demonstrating high binding affinity of [NOTA-8-Aoc-BBN] for the GRPr. [(64)Cu-NOTA-X-BBN] conjugates were prepared by the reaction of (64)CuCl(2) with peptides in buffered aqueous solution. In vivo studies of [(64)Cu-NOTA-8-Aoc-BBN(7-14)NH(2)] in tumor-bearing PC-3 mouse models indicated very high affinity of conjugate for the GRPr. Uptake of conjugate in tumor was 3.58 +/- 0.70% injected dose (ID) per g at 1 h postintravenous injection (p.i.). Minimal accumulation of radioactivity in liver tissue (1.58 +/- 0.40% ID per g, 1 h p.i.) is indicative of rapid renal-urinary excretion and suggests very high in vivo kinetic stability of [(64)Cu-NOTA-8-Aoc-BBN(7-14)NH(2)] with little or no in vivo dissociation of (64)Cu(2+) from the NOTA chelator. Kidney accumulation at 1 h p.i. was 3.79 +/- 1.09% ID per g. Molecular imaging studies in GRPr-expressing tumor models produced high-contrast, high-quality micro-positron-emission tomography images.

Prostate cancer clinical trial end points: "RECIST"ing a step backwards

PURPOSE

To relate clinical issues to the clinical manifestations of prostate cancers across disease states using the eligibility and outcome criteria defined by Response Evaluation Criteria in Solid Tumors (RECIST).

EXPERIMENTAL DESIGN

The manifestations of prostate cancer that characterize localized, recurrent, and metastatic disease were considered using the eligibility criteria for trials defined by RECIST. To do so, we analyzed the sites, size, and distribution of lesions in patients enrolled on contemporary Institutional Review Board-approved trials for progressive castrate and noncastrate metastatic disease. Prostate-specific antigen (PSA) levels were also assessed. RECIST-defined outcome measures for tumor regression were then applied to the metastatic patient cohorts, and separately to the states of a rising PSA (noncastrate and castrate) and localized disease.

RESULTS

Only 43.5% of men with castrate metastatic and 16% of noncastrate metastatic disease had measurable target lesions > 2 cm in size. Overall, 84.4% of the target lesions were lymph nodes, of which 67.7% were > or = 2 cm in the long axis. There are no target lesions in patients in the states of a rising PSA and localized disease, making them ineligible for trials under these criteria. PSA-based eligibility and outcomes under RECIST conflict with established reporting standards for the states of a rising PSA and castrate metastatic disease. The clinical manifestations of prostate cancer across multiple disease states are not addressed adequately using the eligibility criteria and outcomes measures defined by RECIST. Important treatment effects are not described.

CONCLUSIONS

Trial eligibility and end points based solely on tumor regression are not applicable to the majority of the clinical manifestations of prostate cancers representing all clinical states. Treatment effects can be described more precisely if eligibility criteria are adapted to the clinical question being addressed and clinical state under study, focusing on the duration of benefit defined biochemically, radiographically, and/or clinically.

The selectivity and specificity of the actions of the lipido-sterolic extract of Serenoa repens (Permixon) on the prostate

PURPOSE

To investigate the effects of the phytotherapeutic agent, Permixon(R), on primary cultures of fibroblast and epithelial cells from the prostate, epididymis, testes, kidney, skin and breast and to determine the selectivity and specificity of the action of the drug.

MATERIALS AND METHODS

All primary cultures were examined by electron microscopy before and following treatment with Permixon(R) (10 microg./ml.). In addition the apoptotic index was assessed by flow cytometry employing propidium iodide as a fluorophore. The impact of the drug on 5alpha-reductase (5alphaR) isoenzymes was also tested utilizing a pH specific assay.

RESULTS

There were changes in the morphology of prostate cells after treatment including accumulation of lipid in the cytoplasm and damage to the nuclear and mitochondrial membranes; no similar changes were observed in other cells. Permixon(R) increased the apoptotic index for prostate epithelial cells by 35% and 12% in the prostate stromal/fibroblast. A lesser apoptotic effect was demonstrated in skin fibroblast (3%) whereas none of the other primary cultures showed any increase in apoptosis when compared with the controls. Permixon(R) was also an effective inhibitor of both 5alphaR type I and II isoenzymes in prostate cells, but other cells showed no inhibition of 5alphaR activity following treatment with the plant extract.

CONCLUSIONS

This investigation demonstrated the selectivity of the action of Permixon(R) for prostate cells. The morphological changes in the prostate are accompanied by an increase in the apoptotic index along with an inhibition in the activity of the nuclear membrane bound 5alphaR isoenzymes. No similar changes were observed in any of the other cells under investigation.

Defining an international research agenda for quality of life in men with prostate cancer

BACKGROUND

While the traditional goal in the management of patients with prostate cancer has been to maximize survival, the recent advent of the medical outcomes movement has underscored the importance of patient-centered issues, such as health-related quality of life (HRQOL).

METHODS

In this paper we present a comprehensive approach to the study of HRQOL in men with prostate cancer. We begin by defining HRQOL in general, discussing its measurement, and placing it in the context of prostate cancer. We then describe the primary goals of HRQOL research and present examples of validated instruments. We finish by proposing a quality of life research agenda for the next two decades.

RESULTS

Contemporary perspectives on HRQOL are based on the World Health Organization's definition of health as not merely the absence of disease, but as a state of physical, emotional, and social well-being. HRQOL measurement must adhere to the strict methodological principles of survey psychometrics and is best accomplished with any of several validated instruments. Once collected, HRQOL information is useful for prostate cancer patients facing difficult treatment decisions.

CONCLUSIONS

A solid foundation for HRQOL research has been built in early- and late-stage prostate cancer. It includes the development of new instruments and the establishment of descriptive data. This groundwork will allow investigators to address more complex research issues, such as interpreting interactions among HRQOL domains, presenting HRQOL data to future patients, optimally timing HRQOL data collection, uncovering innate and alterable factors that influence HRQOL, and exploring the intercultural nuances of HRQOL assessment.

Exposure to hyperbaric oxygen induces cell cycle perturbation in prostate cancer cells

Cell cycle synchronization of tumor cells by exposure to hyperbaric oxygenation (HBO) may increase the efficacy of chemotherapy or radiation by placing cells into a chemosensitive portion of the cycle. The purpose of the current study was to examine oxygen pressure-dependent relationships with respect to the cell cycle in prostate tumor cells in vitro. LNCaP cells were grown in an incubator at 21% O2 and then exposed to 100% oxygen at pressures up to 6 atmospheres (atm) for 1.5 h. Cells were then returned to the incubator and evaluated for DNA content by propidium iodide and new DNA synthesis with a pulse-chase experiment. Cell cycle effects were evaluated by flow cytometry. Exposure to HBO increased the percentage of cells synthesizing new DNA in a dose-dependent fashion: 0 atm, 44%; 6 atm, 65%. Cells that synthesize new DNA accumulate in G2/M as a function of partial pressure of oxygen. These results suggest that HBO induces cells to enter the cell cycle and accumulate in G2/M. Cell cycle synchronization and entry of senescent cells into the cell cycle suggest that HBO may be a useful adjuvant to chemotherapy or radiation in the treatment of prostate cancer. There are two potential mechanisms of action that may make HBO efficacious in the treatment of prostate cancer. HBO may potentiate cancer chemotherapeutic agents that cause damage to DNA during DNA synthesis or HBO may inhibit cell division causing accumulation in G2/M.

Fatty acid composition of phospholipids in epithelium and stroma of human benign prostatic hyperplasia

BACKGROUND

Although it is well known that prostatic 5alpha-reductase is active only in its membrane-bound form, rather limited information is available concerning the composition of cellular lipids in human BPH. Therefore, in the present study, the phospholipid fatty acid composition and content in epithelium and stroma of human BPH have been investigated for the first time.

METHODS

Phospholipids separated on TLC plates were methylated and fatty acid methyl esters were analyzed by capillary gas chromatography.

RESULTS

The fatty acid composition of total phospholipids was significantly different between epithelium and stroma. In particular, the percentage of oleic acid was significantly higher in epithelium as compared with stroma, whereas that of arachidonic acid was significantly lower in epithelium than in stroma. In addition, significant differences between epithelium and stroma were found in regard to the fatty acid composition of the main phospholipid subclasses. Another remarkable finding were the age-dependent changes of the fatty acid composition in human BPH.

CONCLUSIONS

This study shows that the fatty acid composition of phospholipids is significantly different between epithelium and stroma of human BPH. Furthermore, age-dependent alterations of the fatty acid composition were found. Further studies are needed to determine whether the endogenous hormonal milieu in the prostate modulates the fatty acid composition of the prostatic cells, as well as what impact such modulation could have on the properties of membrane proteins, i.e., enzymes like the 5alpha-reductase and receptors, which are thought to be affected by alterations in membrane fluidity or composition, or both.