Fibroblast growth factor-2 and TPA enhance prostate-cancer-cell proliferation and activate members of the Ras and PKC signal transduction pathways.

Rat prostate-cancer-cell stable-transfectants expressing either antisense-fibroblast growth factor (FGF-1) or antisense-FGF-2 transcripts that respectively have either undetectable FGF-1 or profoundly diminished FGF-2 protein content, were used for analyses of FGF-2 and/or 12-O-tetradecanoylphorbol 12-acetate (TPA) modulation of cell proliferation. Antisense-FGF-2 transfectant doubling-time was 2.6-fold greater than that of vector-control transfectants. FGF-2 and TPA respectively caused 2.5- and 3.0-fold reductions in antisense-FGF-2 transfectant doubling-time. Culture of antisense-FGF-2 transfectants in medium containing both FGF-2 and TPA further reduced their doubling time; however, this effect was not statistically different from that achieved by TPA treatment alone. Antisense-FGF-1 transfectant doubling-time was 2.2-fold greater than that of vector-control transfectants and was reduced 2.0- or 2.3-fold, respectively, when these cells were cultured in medium containing FGF-2 or TPA. In contrast to the results for antisense-FGF-2 transfectants, culture of antisense-FGF-1 transfectants in medium containing both FGF-2 and TPA caused a 2.6-fold reduction in transfectant doubling-time that was significantly greater than that caused by independent treatment with either FGF-2 or TPA. FGF-2 promoted rapid activation of rat prostate-cancer-cell PKCalpha and PKCepsilon, as assessed by isozyme translocation from the soluble to particulate cell fraction, and only moderately altered PKCdelta distribution. By contrast, TPA promoted rapid activation of all three PKC isozymes. Both the TPA- and FGF-2-mediated PKC activation were prolonged and possibly involved cyclic redistribution of isozymes between soluble and particulate cell fractions. FGF-2 also caused rapid phosphorylation of prostate-cancer-cell Shc, the adapter protein that mediates FGF-receptor-modulated ras signaling. The results of these studies indicate that FGF-2 and TPA independently and conjointly modulate rat prostate-cancer-cell antisense-transfectant doubling time and suggest that effector modulation of rat prostate-cancer-cell proliferation is achieved by processes involving PKC and/or ras mediated signaling.

Protein kinase C-dependent and -independent pathways of signal transduction in prostate cancer cells: fibroblast growth factor utilization of a protein kinase C-independent pathway.

To examine the possibility that differences in protein tyrosine phosphorylation contributed to differences in fibroblast growth factor (FGF) responsiveness of clonally derived C3 (modestly responsive) and T5 (highly responsive) rat prostate cancer cells, we evaluated the ability of orthovanadate to affect prostate cancer cell thymidine incorporation. These analyses showed that C3 cell FGF insensitivity was not attributable to enhanced protein phosphotyrosine phosphatase activity. Analyses of acidic FGF (aFGF)-mediated protein phosphorylation showed mitogen-caused, time-dependent tyrosine phosphorylation of C3 and T5 cell FGF receptors (FGFRs) and other proteins having a mass of 190, 150, 120, 100, 90, 80, 74, 60/62, 50, 42, or 28 kilodaltons. Although marked differences characterized aFGF mediated intensity of tyrosine phosphorylation, the notable commonality of tyrosine phosphorylation and the mass of the phosphorylated proteins suggested that C3 and T5 cells may use the ras and/or protein kinase C (PKC) pathways for FGF-mediated signal transduction. The PKC agonist 12-O-tetradecanoyl-phorbol-13-acetate (TPA) caused concentration-dependent increases in T5 cell thymidine incorporation. In contrast, TPA did not enhance thymidine incorporation of C3 cells or mitogen-sensitive NRK cells included as a nonneoplastic control. TPA also significantly enhanced T5 cell proliferation, whereas identical treatment did not affect proliferation of either C3 or NRK cells. Either 12 or 24 h treatment with 200 or 2000 ng/ml TPA caused complete PKC alpha and partial PKC delta down-regulation in C3, T5, and NRK cells. Consequently, the failure of TPA to affect C3 or NRK cell thymidine incorporation or proliferation was not attributable to potential TPA ineffectiveness in these cells. Survey immunological analyses showed that all three cell lines lacked PKC beta, PKC eta, and PKC theta. In contrast, T5 cells contained abundant amounts of PKC epsilon, whereas the PKC epsilon content of C3 and NRK cells was near the limit of detection. TPA treatment of T5 cells evoked only partial PKC epsilon down-regulation. Both aFGF and basic FGF (bFGF) promoted concentration-dependent enhancement of TPA-pretreated T5 cell thymidine incorporation, and the effects of combined TPA and either aFGF or bFGF treatment were additive. Neither aFGF nor bFGF was able to enhance thymidine incorporation of TPA-pretreated C3 cells beyond the modest effects elicited by FGF treatment of C3 controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Antitumorous and immunomodulatory effects of the Viscum album L. preparation Isorel.

There are numerous data on the immunostimulative and antitumorous activity of various Viscum album tissue extracts. Isorel (Novipharm, Austria) is one of these compounds. We found that in mice an increased number of plaque-forming cells to sheep red blood cells (SRBC) followed the injection of Isorel together with SRBC. Further, survival time of a foreign skin graft was shortened if Isorel was applied at the correct time. Finally, suppressed immune reactivity in tumorous mice recovered following Isorel injection. Isorel was further shown to be cytotoxic to tumor cells in vitro. Its application to tumor-bearing mice could prolong their life but without any therapeutic effect. However, a combination of local irradiation and Isorel was very effective: following 43 Gy of local irradiation to a transplanted methylcholanthrene-induced fibrosarcoma (volume about 240 mm3) growing in syngeneic CBA/HZgr mice, the tumor disappeared in about 25% of the animals; the addition of Isorel increased the incidence of cured animals to over 65%. The combined action of Isorel, influencing tumor viability on the one hand and the host's immune reactivity on the other, seems to be favorable for its antitumor action in vivo.

Mitogenicity of the earthworm's (Eisenia foetida) insulin-like proteins.

1. Biologically active glycolipoprotein complex (G-90), isolated from whole earthworm tissue extract (Eisenia foetida), was separated into seven fractions by gel-filtration. 2. It has been shown by radioimmunoassay that each of the fractions, except the lightest one, is cross-reactive with porcine anti-insulin antibodies. Molecules that possess such activity were detected by immunoblotting. 3. All fractions, except the heaviest and the lightest one, stimulate mammalian normal and transformed cell proliferation in serum-free conditions in vitro. The intensity of stimulation depends on cell type. Stimulation is completely abolished if the medium is supplemented with fetal calf serum.

A new source of biologically active compounds--earthworm tissue (Eisenia foetida, Lumbricus rubelus).

1. Earthworms possess immunological recognition and memory as well as high regenerative abilities. Coelomic fluid was used as a source of biologically active compounds. 2. A biologically active glycolipoprotein extract from a whole earthworm tissue homogenate was isolated and named G-90. 3. G-90 forms precipitation arcs in gel with different animal and human sera. 4. It alters murine cell growth rate in vitro in serum in a dose-dependent manner and slows murine tumor growth in vivo. 5. G-90 does not contain mutagens or carcinogens.