Nerve growth factor signaling of p75 induces differentiation and ceramide-mediated apoptosis in Schwann cells cultured from degenerating nerves.

In peripheral nerve regeneration or remyelination, immature Schwann cells expressing p75(NTR) play cardinal roles in the support and regeneration of axons (Griffin JW, Hoffman PN. Peripheral Neuropathy 361-376, 1993). Only one of four to six Schwann cells participate in remyelination of damaged or regenerating axons. The rest of the cells, or supernumerary Schwann cells, show severe atrophy and gradually decrease in number, reestablishing a 1:1 axon-Schwann cell relationship (Said G, Duckett S. Acta Neuropathol (Berl) 53:173-179, 1981). Recent reports demonstrated that severely atrophied supernumerary Schwann cells are eliminated by apoptosis during axonal regeneration or remyelination (Hirata H, Hibasami H. Apoptosis 3:353-360, 1998; Berciano MT, Calle E. Acta Neuropathol (Berl) 95:269-279, 1998). The mechanism to induce selective death of supernumerary Schwann cells without causing any damage to axon-associated Schwann cells or axons remains to be determined. In this article, we report that p75(NTR), the low-affinity receptor for all members of neurotrophins, signals both cell differentiation and apoptosis through intracellular ceramide elevation. The final response is dependent on the intracellular ceramide level and Schwann cells modulate their response by changing expression level of p75(NTR). This effect was selective for nerve growth factor (NGF). Taken together, the present study suggests that NGF contributes both to phenotypic regulation and to elimination of the dedifferentiated Schwann cells, while supporting survival or regeneration of certain types of axons during peripheral nerve repair or regeneration.

Sesaminol from sesame seed induces apoptosis in human lymphoid leukemia Molt 4B cells.

The exposure of human lymphoid leukemia Molt 4B cells to sesaminol, a component of sesame oil led to both growth inhibition and the induction of apoptosis. Morphological change showing apoptotic bodies was observed in the cells treated with sesaminol. The fragmentation of DNA by sesaminol to oligonucleosomal-sized fragments that are characteristics of apoptosis was observed to be concentration- and time-dependent. These findings suggest that growth inhibition of Molt 4B cells by sesaminol results from the induction of apoptosis in the cells.

Sesamolin from sesame seed inhibits proliferation by inducing apoptosis in human lymphoid leukemia Molt 4B cells.

The exposure of human lymphoid leukemia Molt 4B cells to sesamolin, a component of sesame seed led to both growth inhibition and the induction of apoptosis. Morphological change showing apoptotic bodies was observed in the cells treated with sesamolin. The fragmentation of DNA by sesamolin to oligonucleosomal-sized fragments that are characteristics of apoptosis was observed to be concentration- and time-dependent. These findings suggest that growth inhibition of Molt 4B cells by sesamolin results from the induction of apoptosis in the cells.

Sodium 1-monolinolenin isolated from Italian ryegrass (Lolium multiflorum Lam) induces apoptosis in human lymphoid leukemia Molt 4B cells.

The exposure of human lymphoid leukemia Molt 4B cells to sodium 1-monolinolenin (SML) which was isolated from the leaves of Italian ryegrass (Lolium multiflorum Lam) and identified by Mass, and (1)H- and (13)C-NMR, led to both growth inhibition and induction of programmed cell death (apoptosis). Morphological change showing apoptotic bodies was observed in the Molt 4B cells treated with SML. The fragmentation by SML of DNA to oligonucleosomal-sized fragments, that is a characteristic of apoptosis, was observed to be both concentration- and time-dependent. These findings suggest that growth inhibition by SML of Molt 4B cells results from the induction of apoptosis in the cells.

Induction of apoptosis by Acanthopanax senticosus HARMS and its component, sesamin in human stomach cancer KATO III cells.

Antitumor effect of the stem bark of Acanthopanax senticosus HARMS (ASH) from Hokkaido (Japanese name: Ezoukogi) on human stomach cancer KATO III cells was investigated. The extract of the stem bark of ASH prepared with hot water was dissolved in distilled water and used for the assay of antitumor effect on the KATO III cells. The exposure of KATO III cells to ASH led to both growth inhibition and induction of apoptosis. Morphological change showing apoptotic bodies was observed in the cells treated with ASH. The fragmentation by ASH of DNA to oligonucleosomal-sized fragments that are characteristics of apoptosis was observed to be concentration- and time-dependent. We have investigated which component in ASH is effective on the induction of apoptosis. Among chlorogenic acid, syringaresinol di-o-beta-D glucoside, syringin, and sesamin, components of the n-butanol extract prepared from ASH, sesamin suppressed the growth and induced apoptosis in the cells. These findings suggest that growth inhibition by ASH results from the apoptosis induced by sesamin, a component of ASH.

Induction of apoptosis by gallic acid in human stomach cancer KATO III and colon adenocarcinoma COLO 205 cell lines.

Antitumor effects of gallic acid on human stomach cancer KATO III cells and human colon adenocarcinoma COLO 205 cells were investigated. The exposures of KATO III and COLO 205 cells to gallic acid led to both growth inhibition and induction of apoptosis. Morphological changes showing apoptotic bodies were observed in both the cell lines treated with gallic acid. The fragmentations by gallic acid of DNA to oligonucleosomal-sized fragments, that are characteristics of apoptosis, were observed to be concentration- and time-dependent. These findings suggest that growth inhibitions by gallic acid of KATO III cells and COLO 205 cells result from the apoptosis induced by gallic acid. Thus, gallic acid might be a candidate drug for digestive gut cancer treatment to overcome the resistance to chemotherapeutic drugs.

Pheophorbide a, a moiety of chlorophyll a, induces apoptosis in human lymphoid leukemia molt 4B cells.

The exposure of human lymphoid leukemia Molt 4B cells to pheophorbide a (PPB a), a moiety of chlorophyll a, led both to growth inhibition and induction of programmed cell death (apoptosis). The growth inhibition by PPB a was much stronger than that by chlorophyll a. Morphological change showing apoptotic bodies was observed in the Molt 4B cells treated with PPB a. The fragmentation by PPB a of DNA to oligonucleosomal-sized fragments, that are characteristics of apoptosis, was observed to be concentration- and time-dependent. These findings suggest that growth inhibition by PPB a of Molt 4B cells results from the induction of apoptosis and that PPB a, moiety of chlorophyll a, is essential for exertion of antitumor and apoptosis-inducing activity in these cells.

Prevention of metastasis by a polyamine synthesis inhibitor in an animal bone metastasis model.

In order to better understand the development of skeletal metastases, we developed an appropriate animal model, as the natural progression of metastases in humans cannot be studied on the cellular level. In this study, we established a new animal model which developed bone metastasis in a bone grafted subcutaneously. C57BL/6 mice, which had received a bone (femur or tibia) transplanted in the dorsal subcutis, were injected with B16 melanoma cells into the left heart ventricle. Metastasis was found in approximately 70% of the extraskeletal bones. Using this model, the antimetastatic effect of a polyamine synthesis inhibitor was investigated. Inhibitors of the polyamine biosynthetic pathway have received considerable attention for their potential use in the treatment of cancer as they are responsible for the greatly increased production of the polyamines putrescine, spermidine, and spermine. A polyamine synthesis inhibitor, methylglyoxal-bis(cyclopentylamidinohydrazone) MGBCP, was investigated for its inhibitory effects on bone metastases. MGBCP (20 mg/kg) was administered intraperitoneally every day for 4 weeks and demonstrated strong inhibitory effects on bone metastases. MGBCP inhibited angiogenesis in the transplanted bone and the growth of B16 melanoma cells, thus suggesting a preventive mechanism in bone metastasis. No remarkable adverse effects of MGBCP were observed in any animal throughout the experimental period. Our results indicate that MGBCP has a strong potential for use as an anti-metastatic drug.

Sesamin and episesamin induce apoptosis in human lymphoid leukemia Molt 4B cells.

The exposure of human lymphoid leukemia Molt 4B cells to sesamin and episesamin which were isolated from unroasted sesame seed oil and identified by MS, and 1H and 13C-NMR, led to both growth inhibition and the induction of programmed cell death (apoptosis). Morphological change showing apoptotic bodies was observed in the Molt 4B cells treated with sesamin and episesamin. The fragmentations by sesamin and episesamin of DNA to oligonucleosomal-sized fragments that are characteristics of apoptosis were observed to be concentration-dependent, respectively. Moreover, the amount of the DNA fragments in the sesamin-treated cells was increased from 2 days, while that in the episesamin-treated cells was elevated at 3 days after addition of the compounds. These findings suggest that growth inhibitions by sesamin and episesamin of Molt 4B cells result from the induction of apoptosis in the cells.

Oolong tea polyphenol extract induces apoptosis in human stomach cancer cells.

The exposure of human stomach cancer KATO III cells to oolong tea polyphenol extact [OTPE] containing oolong tea polyphenol trimer [OTP trimer] as a main component, led to both growth inhibition and the induction of apoptosis. Morphological change showing apoptotic bodies was observed in the cells treated with OTPE. The fragmentation by OTPE of DNA to oligonucleosomalsized fragments that are characteristics of apoptosis was observed to be concentration- and time-dependent. These data suggest that the growth inhibition by OTPE results from the induction of apoptosis in the KATO III cells.

Phytol induces programmed cell death in human lymphoid leukemia Molt 4B cells.

The exposure of human lymphoid leukemia Molt 4B cells to phytol which was isolated from Lolium multiflorum Lam and identified by MS, and 1H- and 13C-NMR, led to both growth inhibition and the induction of programmed cell death (apoptosis). Morphological change showing apoptotic bodies was observed in the cells treated with phytol. The fragmentation by phytol of DNA to oligonucleosomal-sized fragments that are characteristics of apoptosis was observed to be concentration- and time-dependent. These findings suggest that growth inhibition by phytol of Molt 4B cells results from the induction of apoptosis in the cells.

Induction of apoptotic cell death in human hepatocellular carcinoma SK-HEP-1 cells by a polyamine synthesis inhibitor, methylglyoxal bis(cyclopentylamidinohydrazone).

The antitumor effects of a polyamine biosynthetic pathway inhibitor methylglyoxal bis(cyclopentylamidinohydrazone) (MGBCP) on the human hepatocellular carcinoma SK-HEP-1 cell line have been investigated. The growth of these cultured hepatocellular carcinoma cells was inhibited by MGBCP in a dose-dependent manner. Spermidine and spermine levels were dose-dependently depressed, and morphological changes due to programmed cell death (apoptosis) were observed in these MGBCP-treated hepatocellular carcinoma cells. These results suggest that in addition to reducing the growth rates, MGBCP can induce apoptotic cell death in this human hepatocellular carcinoma cell line.

Growth inhibition of human osteosarcoma HuO9 cells by methylglyoxal bis(cyclopentylamidinohydrazone) in vitro and in vivo.

Polyamines are considered to be important intracellular molecules for the proliferation of cancer cells. In this study, effects of methyl-glyoxal bis(cyclopentylamidinohydrazone) (MGBCP), a potent inhibitor of the polyamine biosynthetic pathway, on the growth of human osteosarcoma HuO9 cells have been investigated. MGBCP dose-dependently inhibited the growth of HuO9 cells, in which the contents of spermine, spermidine and putrescine decreased concomitantly. The MGBCP-treated cells clearly exhibited morphological changes, indicating the blebbing and chromatin condensation which are characteristic of apoptosis. Characteristic oligonucleosomal-sized DNA fragments were observed in the MGBCP-treated cells. In in vivo experiments MGBCP (20 or 50 mg/kg) inhibited the growth of transplanted HuO9 tumors in mice. These findings suggest that the inhibition of polyamine synthesis results in the suppression of growth of osteosarcoma HuO9 cells, eventually inducing apoptosis in these human osteosarcoma cells in vitro and in vivo.

Expression of gp145trkB in the early stage of Schwann cell tube formation.

We investigated the expression of tyrosine kinase receptors (trkBs) and their ligand, brain-derived neurotrophic factor (BDNF), in isolated sciatic nerve segments of rat in a silicone chamber model devoid of axonal contact, using an immunohistochemical technique. The receptor gp 95trkB was not detected during the first 3 weeks but was strongly expressed in the nerve stumps on day 21. In contrast, gp 145trkB immunoreactivity was readily detected in the Schwann cells in the nerve stumps between days 1 and 7 after isolation. Immunohistochemical analysis using anti-S-100 antibody demonstrated that Schwann cell tube formation within the silicone chamber had been completed by the third week, which suggested that gp 95trkB began to be produced by Schwann cells after completion of Schwann cell tube formation. Considering the low level of BDNF production during the first week, molecules other than BDNF may be ligands for gp 145trkB in the silicone chamber model devoid of axonal contact.

Black tea theaflavins induce programmed cell death in cultured human stomach cancer cells.

The exposure of human stomach cancer KATO III cells to black tea theaflavin extract, free theaflavin, and theaflavin digallate that are main components of the extract, led to both growth inhibition and the induction of programmed cell death (apoptosis). Morphological changes showing apoptotic bodies were observed in the cells treated with black tea theaflavin extract, theaflavin and theaflavin digallate. The fragmentations by these theaflavin compounds of DNA to oligonucleosomal-sized fragments that are characteristics of apoptosis were observed to be concentration- and time-dependent. These data suggest that drinking of black tea in large amounts is recommended to protect humans from stomach cancer.

Involvement of apoptosis and cyclin D1 gene repression in growth inhibition of T-47D human breast cancer cells by methylglyoxal bis(cyclopentylamidinohydrazone).

Polyamines are considered to be important intracellular molecules for the proliferation of the cancer cells. In this study, effects of methylglyoxal bis(cyclopentylamidinohydrazone) (MGBCP), a potent inhibitor of the polyamine biosynthetic pathway, on the growth and cell cycle of T-47D human breast cancer cells were investigated. MGBCP dose-dependently inhibited the growth of T-47D cells, in which the contents of spermine, spermidine and putrescine decreased concomitantly. The gene expression of cyclin D1 was also repressed by the MGBCP treatment. The MGBCP-treated cells clearly exhibited morphological changes indicating the blebbing and chromatin condensation which are characteristic of apoptosis. Flow cytometric analysis showed hypo-diploid subpopulations due to apoptotic cells, and characteristic oligonucleosomal-sized DNA fragments were clearly observed for MGBCP-treated cells as the concentration of the drug was increased. These findings suggest that the inhibition of polyamine synthesis results in the repressions of cyclin D1 expression and cell cycle progression, eventually inducing apoptosis in these human breast cancer cells.

Honokiol induces apoptosis in human lymphoid leukemia Molt 4B cells.

The exposure of human lymphoid leukemia Molt 4B cells to honokiol led to both growth inhibition and the induction of apoptosis. Morphological change showing apoptotic bodies was observed in the cells treated with honokiol. The fragmentation by honokiol of DNA to oligonucleosomal-sized fragments that are characteristics of apoptosis was observed to be concentration- and time-dependent. These findings suggest that growth inhibition by honokiol of Molt 4B cells results from the induction of apoptosis in the cells.

Inverse effects of 20K and 22K human growth hormones on the growth of T-47D human breast cancer cells in culture and in nude mice.

The major form of human growth hormone (22K hGH) stimulates the growth of T-47D human breast cancer cells in culture and in nude mice by binding to their receptors for growth hormone and prolactin. Another isoform of hGH having a smaller molecular mass (20K hGH) is known to show different binding affinities to these receptors. In this study, we have analyzed the effects of 20K hGH on the growth of T-47D cells in vitro and in vivo. 20K hGH (50 ng/ml) inhibited the proliferation and DNA synthesis of T-47D cells cultured in the presence and absence of 17 beta-estradiol (100 ng/ml), while 22K hGH (50 ng/ml) promoted the cellular growth. In estradiol-treated nude mice, 22K hGH (100 micrograms) remarkably promoted the growth of T-47D tumor, but 20K hGH again suppressed the tumor growth significantly. The results suggest the presence of different signal pathways for these two hGH isoforms and imply a possible clinical application for 20K hGH.

Cooperative and differential effects of estrogen, prolactin, 22K and 20K human growth hormones on cyclin D1/PRAD1 gene expression in T-47D human breast cancer cells.

The cyclin D1/PRAD1 gene is correlated with carcinogenesis of human breast cancer. In this study, we have analyzed effects of breast cancer-related hormones on the cyclin D1 gene expression in T-47D human breast cancer cells. Estradiol (E2) and human prolactin (hPRL) equally enhanced the cyclin D1 gene expression in the cells, and 22 and 20 kDa human growth hormones (22K and 20K hGHs) showed less stimulatory effects. In the presence of E2, however, hPRL or 22K hGH showed additive stimulations of the cyclin D1 gene expression to that by E2 alone, while 20K hGH did not show any additive stimulation of the gene expression. The results suggest that the signal pathways through estrogen and hPRL receptors are important for cyclin D1 gene expression in breast cancer cells, and that 20K hGH has little effect on the cyclin D1 gene expression in these cells because of its lower affinity to PRL receptor.

Apoptosis induction in human breast cancer MRK-nu-1 cells by a polyamine synthesis inhibitor, methylglyoxal bis(cyclopentylamidinohydrazone)(MGBCP).

We have investigated the antiproliferative effects of a polyamine synthesis inhibitor, methylglyoxal bis(cyclopentylamidinohydrazone) (MCBCP), on human breast cancer MRK-nu-1 cells. MGBCP inhibited tumor growth of MRK-nu-1 cells in a dose-dependent manner as the polyamine contents in the cells decreased. Moreover, morphological changes indicating blebbing and chromatin condensation were observed in the MGBCP-treated cells, and hypodiploid subpopulations containing apoptotic cells were clearly detected in the profile of flow cytometric analysis. The number of characteristic oligonucleosome-sized fragments also increased as the concentration of MGBCP increased. The apoptotic effects of MGBCP were partially prevented by the addition of exogenous spermine. The results presented here suggest that, in addition to reducing the growth rate, MGBCP can induce apoptotic cell death in MRK-nu-1 human breast cancer cells by the reduction of intracellular concentrations of polyamines.