Robert Huryk

High Energy Shock Waves Suppress Tumor Growth in Vitro and in Vivo

Exposure of the Dunning R3327AT-3 rat prostatic carcinoma and SK-Mel-28 human melanoma, in vitro, to high energy shock waves resulted in a reduction in cell viability as determined by trypan blue exclusion and a decrease in the number of colonies formed in a clonogenic assay. Flow cytometric determination of DNA content in R3327AT-3 cells treated in vitro indicated a selective diminution of cells in the G2 and M phases of the cell cycle. When R3327AT-3 cells exposed to high energy shock waves were subsequently injected into rats, or tumor bearing animals were treated by high energy shock waves targeted at the tumor, a delay in tumor growth was observed. These observations indicate that high energy shock waves are cytotoxic to tumor cells in vitro and in vivo. Additional research into the possible use of high energy shock waves in the non-invasive destruction of animal and human tumors is warranted.

VITAMIN E INHIBITS THE HIGH-FAT DIET PROMOTED GROWTH OF ESTABLISHED HUMAN PROSTATE LNCaP TUMORS IN NUDE MICE

PURPOSE Prostate cancer has become an important public health problem in the Western world. It is currently the most common diagnosed cancer and the second leading cause of cancer deaths among North American men. Prostate cancer possesses a unique descriptive epidemiology which suggests that environmental factors (such as dietary fat consumption) play a pivotal role in tumor progression. Data from our institution have demonstrated that diets high in fat content can accelerate the growth of human LNCaP prostate cancer cells. One of the hypothesized mechanisms of dietary fat induced growth is oxidative stress. Our purpose was to determine the effect of supplemental Vitamin E, a potent intracellular antioxidant, on the high-fat promoted growth of transplanted LNCaP cells in the athymic mouse. MATERIALS AND METHODS Tumors were induced by subcutaneous injection of 10(6) LNCaP cells. Mice were fed a control diet consisting of 40.5% of total calories from dietary fat. Once tumors were formed, PSA values were obtained and animals were randomized into 4 groups of 12. The animals were then assigned to one of 4 dietary plans. Group 1 received the control diet of 40.5%-kcal fat. Group 2 received the 40.5%-kcal fat diet plus supplemental Vitamin E. Group 3 received a diet of 21.2%-kcal fat. Group 4 received the 21.2%-kcal fat diet plus supplemental Vitamin E. Food intake, animal weights, and tumor volumes were recorded weekly. Survival analyses with time to a target volume of 0.523 cm.3 (defined as failure) were used to compare tumor growth among the 4 groups. Two-sided tests (log rank test) with alpha set at 0.05 were used to determine significance. RESULTS Tumor growth rates were highest in the animals fed a 40.5%-kcal fat diet (p <0.05 group 1). Tumors in animals fed 40.5%-kcal fat plus Vitamin E, 21.2%-kcal fat, and 21.2%-kcal fat plus Vitamin E, experienced statistically indistinguishable growth rates. No significant differences were noted in total ingested calories, animal weight gain or initial PSA levels. CONCLUSIONS These data suggest that the mechanism of dietary fat induced growth of human prostate cancer cells is mediated by oxidative stress. It also raises the possibility of a therapeutic benefit of vitamin E in preventing prostate cancer.

Histopathologic and ultrastructural correlates of tumor growth suppression by high energy shock waves

High energy shock waves (HESW) are cytotoxic to tumor cells as determined by vital staining and impaired ability of viable cells to form colonies in a clonogenic assay. In addition, direct exposure of tumor nodules to HESW results in suppression of tumor growth rate. In order to identify histopathologic and ultrastructural correlates of these observations, R3327AT-3 prostatic tumor cells were exposed to HESW in vitro and in vivo. Damage to cells in suspension was manifested by fragmentation of cells to form debris. At the ultrastructural level, mitochondria were swollen and contained distorted cristae following exposure of tumor cells to HESW. In vivo exposure of tumor nodules to HESW did not cause a distinct histopathologic or ultrastructural effect that could be qualitatively distinguished from spontaneously occurring cell death. Hemorrhage and necrosis were observed in muscle and fibroadipose tissue adjacent to tumor. The mechanism of HESW-induced cytotoxicity is not clear from our studies. Evidence of damage of normal tissues exposed in vivo and tumor cells in vitro is reflected in histomorphological changes.

Cytotoxicity of high energy shock waves: methodologic considerations.

In vivo and in vitro experimentation with high energy shock waves (HESW) is necessary to further our understanding of the biologic effects and potential application of this novel energy form. Factors are identified which are critical to the design and subsequent interpretation of HESW experimentation. First, the nature of the containment vessel and the presence or absence of acoustic interfaces are shown to significantly alter the outcome of cell suspension experiments. Second, the effects of HESW are shown to differ markedly for cells in suspension versus cells in tissue making comparisons between the two uncertain. Finally, the need for appropriate negative controls is demonstrated with in vivo experiments to control for the generalized toxicity which occurs when small animals are exposed to such an intense force distributed over a relatively large area. These findings affect the interpretation of previously reported work which investigated the cytotoxic potential of HESW.

Alterations of prostate biomarker expression and testosterone utilization in human LNCaP prostatic carcinoma cells by garlic-derived S-allylmercaptocysteine

This study determined the effects of S‐allylmercaptocysteine (SAMC), a phytoconstituent from garlic, on the expression of androgen‐responsive biomarkers, prostate specific antigen (PSA), and prostate specific membrane antigen (PSMA), in human prostatic carcinoma cells (LNCaP).

Prostatic tumor implantation in the nude mouse via a perineal approach.

We describe a novel technique for tumor implantation into the prostate of a nude mouse, using a perineal approach. This technique offers the benefit of being able to accurately implant malignant cells into the dorsal prostate without entering the abdominal cavity. Prostate 33:60–63, 1997.