Advanced prostate cancer: an update

A number of therapeutic options are available or on the horizon for patients for whom initial treatment of localized prostate cancer has failed. Currently under study are time of therapy, maximum androgen blockade, and palliative and adjunctive therapies.     

Cryosurgical technique: assessment of the fundamental variables using human prostate cancer model systems

Cryosurgery offers a promising therapeutic alternative for the treatment of prostate cancer. While often successful, complete cryoablation of cancerous tissues sometimes fails due to technical challenges. Factors such as the end temperature, cooling rate, duration of the freezing episode, and repetition of the freezing cycle have been reported to influence cryosurgical outcome. Accordingly, we investigated the effects of these variables in an in vitro prostate cancer model. Human prostate cancer PC-3 and LNCaP cultures were exposed to a range of sub-zero temperatures (−5 to −40 °C), and cells were thawed followed by return to 37 °C. Post-thaw viability was assessed using a variety of fluorescent probes including alamarBlue™ (metabolic activity), calceinAM (membrane integrity), and propidium iodide (necrosis). Freeze duration following ice nucleation was investigated using single and double freezing cycles (5, 10, and 20 min). The results demonstrated that lower freezing temperatures yielded greater cell death, and that LNCaP cells were more susceptible to freezing than PC-3 cells. At −15 °C, PC-3 yielded 55% viability versus 20% viability for LNCaP. Double freezing cycles were found to be more than twice as destructive versus a single freeze–thaw cycle. Both cell types experienced increased cell death when exposed to freezing temperatures for longer durations. When thawing rates were considered, passive (slower) thawing following freezing yielded greater cell death than active (faster) thawing. A 20% difference in viability between passive and active thawing was observed for PC-3 for a 10 min freeze. Finally, the results demonstrate that just reaching −40 °C in vitro may not be sufficient to obtain complete cell death. The data support the use of extended freeze times, multiple freeze–thaw cycles, and passive thawing to provide maximum cell destruction.     

Statistically integrated metabonomic-proteomic studies on a human prostate cancer xenograft model in mice

A novel statistically integrated proteometabonomic method has been developed and applied to a human tumor xenograft mouse model of prostate cancer. Parallel 2D-DIGE proteomic and 1H NMR metabolic profile data were collected on blood plasma from mice implanted with a prostate cancer (PC-3) xenograft and from matched control animals. To interpret the xenograft-induced differences in plasma profiles, multivariate statistical algorithms including orthogonal projection to latent structure (OPLS) were applied to generate models characterizing the disease profile. Two approaches to integrating metabonomic data matrices are presented based on OPLS algorithms to provide a framework for generating models relating to the specific and common sources of variation in the metabolite concentrations and protein abundances that can be directly related to the disease model. Multiple correlations between metabolites and proteins were found, including associations between serotransferrin precursor and both tyrosine and 3-D-hydroxybutyrate. Additionally, a correlation between decreased concentration of tyrosine and increased presence of gelsolin was also observed. This approach can provide enhanced recovery of combination candidate biomarkers across multi-omic platforms, thus, enhancing understanding of in vivo model systems studied by multiple omic technologies.     

Erythropoietin in cancer: an update

Erythropoietin (EPO) has long been recognized as the major hematopoietic cytokine regulating normal erythropoiesis. Moreover, there is a growing interest in the non-erythropoietic, tissue-protective effects of EPO. Because of its potential to correct anemia, EPO has been increasingly prescribed to cancer patients. However, although recombinant human Epo (rHuEPO) significantly reduces the risk for red blood cell transfusions in cancer patients, recent clinical studies have reported decreased survival and disease control following rHuEPO treatment in patients with different cancer types. The issue of EPOR expression in tumor cells is critical in this respect. The expression of EPOR in tumor cells raises the possibility that exogenous rHuEPO may directly influence tumor growth or sensitivity to chemo-radiation therapy. In addition, EPOR expression in endothelial cells suggests what potential effects EPO may have on tumor capillaries, such as the stimulation of angiogenesis. However, as experimental studies reveal, the overall direct effect of EPO-EPOR signaling on cancer progression and therapy is not a straightforward one. The current paper provides an update on the biology of EPO, and discusses its utility in the treatment of cancer patients.     

Growth factors in human prostate cancer cells: implications for an improved treatment of prostate cancer

It has been previously shown that estrogens may exert their action on human breast cancer cells through coordinated control of secreted growth factors which act in an autocrine and paracrine fashion. Growth stimulation of the androgen receptor negative prostate carcinoma cell line DU-145 by dihydrotestosterone in the presence of the androgen-responsive human prostate carcinoma cell line LNCaP now indicates that androgens may regulate growth of prostate carcinoma cells through related mechanisms. A variety of androgen-regulated growth modulatory activities with autocrine and paracrine potential can be detected in conditioned media from LNCaP cells partially purified by ion exchange chromatography. Androgen-induced growth of LNCaP cells is partially inhibited by the polyanions suramin and dextran sulfates which antagonize growth factor action. These data suggest the existence of at least two different mechanisms of growth regulation by androgen which can be distinguished by their different sensitivity to growth factor inhibitory agents. We conclude that the combination of antipeptidergic substances and androgen withdrawal would represent a new and promising strategy for treatment of human prostate cancer.     

Chemoprevention of prostate cancer with selenium: an update on current clinical trials and preclinical findings

Prostate cancer is the most common cancer diagnosed and the second leading cause of cancer-related deaths in men in the United States. The etiological factors that give rise to prostate cancer are not known. Therefore, it is not possible to develop primary intervention strategies to remove the causative agents from the environment. However, secondary intervention strategies with selenium (Se) compounds and other agents represent a viable option to reduce the morbidity and mortality of prostate cancer. In this review, we discuss ongoing clinical trials. In addition, we discuss preclinical mechanistic studies that provide insights into the biochemical and molecular basis for the anti-carcinogenic activity of both inorganic and organic forms of Se.     

Proteomics in prostate cancer research

The incidence of early prostate cancer (PCa) among middle-aged men has increased rapidly. For many of these men, curatively intended treatment does more harm than good. Established prognostic factors are tumor stage and grade. As a result of earlier detection a majority of patients now have nonpalpable tumors (T1c) of intermediate grade (Gleason score 6). Prostate specific antigen in serum in such cases is generally at a low level and not a reliable predictor of prognosis. Altogether there is an urgent need for adjunctive prognostic indicators. In the search for relevant tumor markers for improved patient selection an exploration of the proteome (the human proteins) could be fruitful. This paper critically reviews the use of 2-dimensional gel electrophoresis (2-DE) for proteome research. Additional steps such as image analysis and mass spectrometry are described. Techniques based on non-2-DE platforms: surface-enhanced laser desorption/ionization (SELDI), isotope coded affinity tags (ICAT) and array-based technologies are also summarized. Although labor-intensive and time-consuming, 2-DE is presently the most powerful method for analysis of cellular protein phenotype and may potentially reveal gene regulations that cannot be detected on a genetic level.     

Monoamines in autism: an update of neurochemical research on a pervasive developmental disorder

Recent neurochemical studies of norepinephrine (NE), dopamine (DA), and serotonin (5HT) in autism are reviewed. Most studies of the catecholamines, their metabolites, and associated enzymes have not found differences between autistic and normal subjects. However, a robust increase in platelet 5HT has been well replicated and characterized. Studies on the possible causes of the increased platelet 5HT in autism suggest that an alteration in platelet physiology is the cause of the increase. Future directions for research on the platelet are discussed as are other potentially fruitful methods for examining monoamine functioning in autism.     

Culturing precision-cut human prostate slices as an in vitro model of prostate pathobiology

Due to the complex morphology of the prostate, it was hypothesized that precision-cut tissue slices from human prostate would provide a unique in vitro model. Precision-cut slices were generated from zones of human prostate and their viability was assessed under conditions of different media for up to 120 h. Slices were also exposed to several concentrations of CdCl₂, which was used as a model toxicant. Maintenance of both stromal and epithelial cells was noted; however, there was a gradual loss of luminal epithelial cells when the medium was not supplemented with dihydrotestosterone (DHT). Minimal leakage of lactate dehydrogenase occurred throughout the incubation. Prostate-specific antigen (PSA) was detected in the medium at all time points, although the rates of secretion fell over time. There was a loss of PSA-positive cells when the medium was not supplemented with DHT, consistent with a loss of luminal cells, whereas PSA-positive cells were maintained in the DHT-supplemented media. A proliferation of basal cells was observed in the presence of media containing 10% fetal bovine serum. Exposure of slices to CdCl₂ demonstrated a dose-response effect ranging from proliferation to complete cellular necrosis. Given the retention of stromal-epithelial interactions and the use of acquired human tissue, prostate slices represent a unique in vitro model for investigating human prostate pathobiology. This revised version was published online in July 2006 with corrections to the Cover Date.     

Vesicle traffic through intercellular bridges in DU 145 human prostate cancer cells

We detected cell-to-cell communication via intercellular bridges in DU 145 human prostate cancer cells by fluorescence microscopy. Since DU 145 cells have deficient gap junctions, intercellular bridges may have a prominent role in the transfer of chemical signals between these cells. In culture, DU 145 cells are contiguous over several cell diameters through filopodial extensions, and directly communicate with adjacent cells across intercellular bridges. These structures range from 100 nm to 5 microm in diameter, and from a few microns to at least 50-100 microm in length. Time-lapse imagery revealed that (1) filopodia rapidly move at a rate of microns per minute to contact neighboring cells and (2) intercellular bridges are conduits for transport of membrane vesicles (1-3 microm in diameter) between adjacent cells. Immunofluorescence detected alpha-tubulin in intercellular bridges and filopodia, indicative of microtubule bundles, greater than a micron in diameter. The functional meaning, interrelationship of these membrane extensions are discussed, along with the significance of these findings for other culture systems such as stem cells. Potential applications of this work include the development of anti-cancer therapies that target intercellular communication and controlling formation of cancer spheroids for drug testing.     

Patenting for the research scientist: an update

Academic institutional research constantly produces results worthy of patent protection, but coping with the demands of patent law presents considerable challenges to bioscientists working in these institutions. Inventors need, however, to be aware of recent patent office guidelines and court decisions if they are to seek useful intellectual property as a basis for technology transfer to industry.     

Vaccines for colorectal cancer: an update

Colorectal cancer (CRC) is known as the third most common and fourth leading cancer associated death worldwide. The occurrence of metastasis has remained as a critical challenge in CRC, so that distant metastasis (mostly to the liver) has been manifested in about 20%-25% of patients. Several screening approaches have introduced for detecting CRC in different stages particularly in early stages. The standard treatments for CRC are surgery, chemotherapy and radiotherapy, in alone or combination. Immunotherapy is a set of novel approaches with the aim of remodeling the immune system battle with metastatic cancer cells, such as immunomodulatory monoclonal antibodies (immune checkpoint inhibitors), adoptive cell transfer (ACT) and cancer vaccine. Cancer vaccines are designed to trigger the intense response of immune system to tumor-specific antigens. In two last decades, introduction of new cancer vaccines and designing several clinical trials with vaccine therapy, have been taken into consideration in colon cancer patients. This review will describe the treatment approaches with the special attention to vaccines applied to treat colorectal cancer.     

Hypercalcemia and cancer: an update.

Hypercalcemia is a not infrequent complication of cancer that every physician should be aware of. It is a significant factor in the morbidity and mortality of cancer patients. Almost invariably hypercalcemia is associated with accelerated resorption of bone, which is thought to be mediated by humoral or metabolic factors. Three such factors, parathyroid hormone, E2 prostaglandins and osteoclast activating factor, have been strongly implicated in the pathogenesis of hypercalcemia in cancer patients. Other mechanisms for the hypercalcemia may exist. Accurate diagnosis of the disorder is important in therapy, and current research into the various mechanisms for hypercalcemia in cancer patients may well lead to new modes of therapy that are more specific and perhaps less toxic.