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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Diverse classes of phytochemicals initiate biological responses that effectively lower cancer risk. One class of phytochemicals, broadly defined as pure and mixed isoprenoids, encompasses an estimated 22,000 individual components. A representative mixed isoprenoid, gamma-tocotrienol, suppresses the growth of murine B16(F10) melanoma cells, and with greater potency, the growth of human breast adenocarcinoma (MCF-7) and human leukemic (HL-60) cells. beta-Ionone, a pure isoprenoid, suppresses the growth of B16 cells and with greater potency, the growth of MCF-7, HL-60 and human colon adenocarcinoma (Caco-2) cells. Results obtained with diverse cell lines differing in ras and p53 status showed that the isoprenoid-mediated suppression of growth is independent of mutated ras and p53 functions. beta-Ionone suppressed the growth of human colon fibroblasts (CCD-18Co) but only when present at three-fold the concentration required to suppress the growth of Caco-2 cells. The isoprenoids initiated apoptosis and, concomitantly arrested cells in the G1 phase of the cell cycle. Both suppress 3-hydroxy-3-methylglutaryl CoA reductase activity. beta-Ionone and lovastatin interfered with the posttranslational processing of lamin B, an activity essential to assembly of daughter nuclei. This interference, we postulate, renders neosynthesized DNA available to the endonuclease activities leading to apoptotic cell death. Lovastatin-imposed mevalonate starvation suppressed the glycosylation and translocation of growth factor receptors to the cell surface. As a consequence, cells were arrested in the G1 phase of the cell cycle. This rationale may apply to the isoprenoid-mediated G1-phase arrest of tumor cells. The additive and potentially synergistic actions of these isoprenoids in the suppression of tumor cell proliferation and initiation of apoptosis coupled with the mass action of the diverse isoprenoid constituents of plant products may explain, in part, the impact of fruit, vegetable and grain consumption on cancer risk.
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PMID:Apoptosis and cell-cycle arrest in human and murine tumor cells are initiated by isoprenoids. 1020 54

Lovastatin, a drug commonly used in the treatment of hypercholesterolemia, has previously been reported to exert potentiated antitumor activity when combined with either tumor necrosis factor-alpha (TNF-alpha), cisplatin or doxorubicin in a melanoma model in mice. Since lovastatin interferes with the function of ras oncogene-encoded (Ras) proteins, we have investigated the antitumor activity of lovastatin and TNF-alpha using a Ha-ras-transformed murine tumor model. In in vitro studies, lovastatin inhibited the growth of cells transformed with Ha-ras oncogene (Ras-3T3 and HBL100-ras cells) more effectively than control NIH-3T3 and HBL100-neo cells. In in vivo experiments, the Ras-3T3 tumor demonstrated significantly increased sensitivity to combined treatment with both lovastatin (50 mg/kg) and TNF-alpha (1 microg/day) compared with either agent alone. Combined treatment with both agents also resulted in greater inhibition of blood-vessel formation. Ras-3T3 tumor cells produced increased amounts of vascular endothelial growth factor (VEGF) and lovastatin effectively suppressed VEGF production by these cells. Our results suggest that lovastatin increases antitumor activity of TNF-alpha against tumor cells transformed with v-Ha-ras oncogene via inhibition of tumor-induced blood-vessel formation.
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PMID:Lovastatin and tumor necrosis factor-alpha exhibit potentiated antitumor effects against Ha-ras-transformed murine tumor via inhibition of tumor-induced angiogenesis. 1022 45

Medulloblastoma is a malignant paediatric central nervous system tumor with a poor prognosis, stimulating the evaluation of improved treatment strategies. Lovastatin, a competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, is currently used to treat patients with hypercholesterolemia. This compound also inhibits the production of non-steroidal mevalonate derivatives that are implicated in the control of cellular proliferation, and can induce cell-cycle arrest in vitro. We recently showed that lovastatin inhibited growth and promoted apoptosis of neuroblastoma, the peripheral nervous system 'cousin' of medulloblastoma. Therefore the potential of lovastatin as a possible anticancer drug against medulloblastoma was evaluated in vitro. Four medulloblastoma cell lines, Daoy, UW228, D341 Med and D283 Med, were treated with 1-40 microM of lovastatin in vitro. Analysis of cell morphologic changes, cell viability, DNA fragmentation and flow cytometry in all four cell lines showed growth inhibition and induction of apoptosis with lovastatin treatment. As little as 10 microM of lovastatin was sufficient to cause a marked reduction in cell numbers, and more than 20 microM of lovastatin induced >90% cells to undergo apoptosis, after intervals ranging between 36 and 96 h, depending on the cell line. Lovastatin induced apoptosis in these cell lines was concomitant with cell cycle arrest in G1. The attached cell lines UW228 and Daoy were more sensitive to lovastatin than D283 Med and D341 Med. Daoy cells which survived several cycles of lovastatin treatment could still be induced to undergo apoptosis after longer treatment times. The efficient induction of apoptosis by lovastatin favours this drug as a potential new avenue of therapeutic intervention for medulloablastoma.
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PMID:Lovastatin-induced apoptosis of human medulloblastoma cell lines in vitro. 1036 Apr 74

The HMGCoA reductase inhibitor Lovastatin (LOV) has previously shown to abrogate p21ras farnesylation, which is associated with invasive and metastatic abilities in many tumor models. Considering the scarcity of therapeutic resources against metastasis, our objective was to study LOV as an antimetastatic agent on L-TACB rat lymphoma, which as a syngeneic tumor model resembles more closely the situation in human cancer. We also aimed to analyze the effect of LOV on chemoinvasion, motility, metalloproteases secretion, angiogenic capacity, and adhesion to the reconstituted basement membrane Matrigel. Our results showed that LOV caused no effect on cell motility, metalloprotease secretion and neovascularization. Conversely, LOV produced a significant inhibition of invasiveness, which could be a consequence of an impaired cell adhesion to the basement membrane observed. These effects could explain, at least in part, the inhibitory action of LOV on L-TACB rat lymphoma metastases.
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PMID:Inhibitory effect of Lovastatin on spontaneous metastases derived from a rat lymphoma. 1039 Jan 43

For tumor progression, a cascade of linked sequential biological events is essential. We tried to test whether biological therapy can modulate specific biological phenotypes and increase the anti-tumor effect when combined with chemotherapy. Five human gastric cancer cell lines (YCC-1, YCC-2, YCC-3, YCC-7, AGS) were used in these studies. Pentosan polysulfate (PPS) as a heparin-binding growth factor inhibitor, Tranexamic acid as a plasmin inhibitor, Lovastatin as an adhesion inhibitor and Adriamycin as a chemotherapeutic agent were selected. The effects of each drug on colony formation and tumor cell proliferation were evaluated by soft agar assay and cell proliferation assay, respectively to test direct anti-tumor effect. The expression of uPA, PAI-1 was determined by ELISA, while MMPs activity was evaluated by zymography. PPS suppressed the colony-forming activity as much as Adriamycin did, but it showed only cytostatic effects in cell proliferation assay. Migration capacity using Boyden chamber assay was more closely correlated with adhesive capacity than uPA or MMP-2 expression. The motility inhibitory effect of Tranexamic acid was observed in the YCC-7 cell line, which expressed all the required biological phenotypes for migration. In AGS, with high cell motility and adhesiveness, the adhesion was inhibited by Lovastatin and most of the inhibitory effect was recovered by Mevalonate. When PPS was combined with Adriamycin on the Adriamycin-resistant, midkine (MK) gene expressing YCC-7 cell line, the growth inhibition rate increased up to 84%, while that for a single treatment of PPS or Adriamycin was 40% and 22%, respectively (p=0.001). When we combined Tranexamic acid and Adriamycin, we observed the synergistic effect in YCC-3 and YCC-7, while no combined effect was found in YCC-1. The combination of Lovastatin and Adriamycin did not show any combined effects in any of the cell lines. In conclusion, a synergistic anti-proliferative effect (chemo-sensitization) with combined chemo-biotherapy was found in cancer cells with specific biological target, MK. The anti-motility effect was the greatest when the gastric cancer cells expressed all the specific biological phenotypes.
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PMID:Modulation of biological phenotypes for tumor growth and metastasis by target-specific biological inhibitors in gastric cancer. 1040 90

Monoterpenes such as limonene and perillyl alcohol (PA) are currently under investigation for their chemotherapeutic properties which have been tied to their ability to affect protein isoprenylation. Because PA affects the synthesis of isoprenoids, such as ubiquinone, and cholesterol is the end product of the synthetic pathway from which this isoprenoid pathway branches, we investigated the effects of this compound upon cholesterol metabolism in the colonic adenocarcinoma cell line SW480. PA (1 mM) inhibited incorporation of 14C-mevalonate into 21-26 kDa proteins by 25% in SW480 cells. Cholesterol (CH) biosynthesis was assessed by measuring the incorporation of 14C-acetate and 14C-mevalonate into 27-carbon-sterols. Cells treated with PA (1 mM) exhibited a fourfold increase in the incorporation of 14C-acetate but not 14C-mevalonate into cholesterol. Mevinolin (lovastatin), an inhibitor of 3-hydroxy-3-methylglutaryl-CoA(HMG-CoA) reductase, at 2 microM concentration, inhibited CH synthesis from 14C-acetate by 80%. Surprisingly, concurrent addition of mevinolin and PA did not significantly alter the stimulatory effects of PA. As observed differences in 14C-acetate and 14C-mevalonate precursor labeling could indicate PA affects early pathway events, the effects of this monoterpene on HMG-CoA reductase activity were evaluated. Unexpectedly, 1 mM PA did not stimulate activity of this enzyme. Consistent with its action as a reversibly bound inhibitor, in washed microsomes, 2 microM mevinolin pretreatment increased reductase protein expression causing a 12.7 (+/- 2.4)-fold compensatory HMG-CoA reductase activity increase; concurrent treatment with 1 mM PA attenuated this to a 5.3 (+/- 0.03)-fold increase. Gas chromatographic analysis confirmed CH was the major lipid present in the measured thin-layer chromatography spot. Since 14C-acetate incorporation into free fatty acid and phospholipid pools was not significantly affected by PA treatment, nonspecific changes in whole acetate pool sizes were not indicated. Because increases in endogenous CH synthesis should result in compensatory changes in exogenous sterol utilization, the effects of PA upon low density lipoprotein (LDL) receptor activity were evaluated. Consistent with the observed increases in CH synthesis, 1 mM PA decreased 125I-LDL internalization to 50% of the fetal bovine serum control; concurrent addition of 2 microM mevinolin attenuated this effect to a reduction of 80% of the control value. Data suggest that in certain colonic tumor cells PA strongly affects cholesterol metabolism via a mechanism of action that is insensitive to the HMG-CoA reductase inhibitor mevinolin.
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PMID:Enhancement of sterol synthesis by the monoterpene perillyl alcohol is unaffected by competitive 3-hydroxy-3-methylglutaryl-CoA reductase inhibition. 1040 75

Hypotension caused by hypovolemic, hemorrhagic shock induces disturbances in the immune system that may contribute to an increased susceptibility to sepsis. The effect of chemically induced hypotension on circulating cytokines and adhesion molecules has not been investigated yet. In 21 patients scheduled for resection of malignant choroidal melanoma of the eye the perioperative serum levels of the cytokines IL-1beta, IL-6, IL-10, TNF-alpha, and the adhesion molecules sE-Selectin and sICAM-1 were investigated. Moderate hypothermia of 32 degrees C was induced in all patients. In 14 patients profound hypotension (mean arterial blood pressure 35-40 mmHg, hypotension group) was induced by enalapril and nitroglycerin for a mean duration of 71 min. In 7 patients the tumor was not resectable, and hypotension was not induced (controls). We did not detect significant differences in serum levels of cytokines or sE-Selectin perioperatively in patients with profound hypotension compared with controls. In both groups IL-6 serum levels increased significantly and reached a maximum after rewarming (17 +/- 6 and 16 +/- 5 pg/dL, respectively, P < 0.001). IL-1beta, IL-10, and TNF-alpha did not change perioperatively in both groups. On the first postoperative day sICAM-1 serum levels were significantly increased in both groups (mean increase of 96 and 54 ng/mL, respectively, P < 0.01 and P < 0.05). We conclude from this study that profound normovolemic arterial hypotension does not seem to have effects on serum levels of circulating IL-1beta, IL-6, IL-10, TNF-alpha, and sE-Selectin. Perioperative moderate hypothermia may be the reason for the postoperative increase in sICAM-1 levels independent of the blood pressure.
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PMID:Effect of profound normovolemic hypotension and moderate hypothermia on circulating cytokines and adhesion molecules. 1056 7

Tumor production of parathyroid hormone-related protein (PTHRP) is responsible for most cases of hypercalcemia of malignancy. The transplantable rat Leydig tumor H-500 is known to cause hypercalcemia in rats by the release of abundant PTHRP and to closely reproduce the human syndrome. We have demonstrated recently that Ras oncogene can stimulate PTHRP gene expression in Fr3T3 fibroblasts in vitro and cause hypercalcemia in vivo. Using rat Leydig tumor H-500 cells, we have investigated the role of effector pathways downstream of Ras in serum-induced PTHRP expression. The Ras inhibitors B-1086 and Lovastatin decreased PTHRP mRNA expression. i.p. administration of B-1086 (50-100 mg/kg/day) into H-500 tumor-bearing male Fischer rats resulted in a dose-dependent reduction in tumor volume, serum calcium, plasma PTHRP, and tumoral PTHRP mRNA expression. Transient transfection of dominant-negative Ras (Ras N17) and Raf (Raf C4B) reduced, whereas activated Raf-1 (Raf BXB) increased, basal expression of PTHRP in H-500 cells. A similar decrease in PTHRP production was seen with a mitogen-activated protein kinase kinase (MEK) inhibitor (PD 098059), implicating the involvement of Ras/Raf/MEK/extracellular signal-regulated kinase (ERK) pathway. In addition, stimulation with UV light, which can activate c-Jun NH2-terminal kinase (JNK), or expression of an activated form of Rac (Rac V12) was sufficient to increase PTHRP mRNA. Moreover, a dominant-negative Rac (Rac N17) blocked serum-induced PTHRP gene expression. Collectively, these results demonstrate that PTHRP is induced via both Raf-ERK and Rac-JNK mediated pathways, effects which can be blocked by chemical inhibitors and dominant-negative mutants of these pathways in vitro and in vivo. Availability of selective inhibitors of Ras signaling molecules may therefore add to our existing armamentarium to control hypercalcemia of malignancy.
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PMID:Role of mitogen-activated protein kinases in the induction of parathyroid hormone-related peptide. 1074 50

Lovastatin, a drug commonly used in the clinic to treat hypercholesterolemia, has previously been reported to exert antitumor effects in rodent tumor models and to strengthen the antitumor effects of immune response modifiers (tumor necrosis factor alpha and IFN-gamma) or chemotherapeutic drugs (cisplatin). In the present report, we show in three murine tumor cell lines (Colon-26 cells, v-Ha-ras-transformed NIH-3T3 sarcoma cells, and Lewis lung carcinoma cells) that lovastatin can also effectively potentiate the cytostatic/cytotoxic activity of doxorubicin. In three tumor models (Co-ion-26 cells, v-Ha-ras-transformed NIH-3T3 sarcoma cells, and Lewis lung carcinoma cells) in vivo, we have demonstrated significantly increased sensitivity to the combined treatment with both lovastatin (15 mg/kg for 10 days) and doxorubicin (3 x 2.5 mg/kg; cumulative dose, 7.5 mg/kg) as compared with either agent acting alone. Lovastatin treatment also resulted in a significant reduction of troponin T release by cardiomyocytes in doxorubicin-treated mice. This observation is particularly interesting because lovastatin is known to reduce doxorubicin-induced cardiac injury.
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PMID:Lovastatin potentiates antitumor activity and attenuates cardiotoxicity of doxorubicin in three tumor models in mice. 1081 31

HMG-CoA (3-hydroxy-3-methylglutaryl coenzyme A) reductase, the rate limiting enzyme in cholesterol synthesis, catalyses mevalonate production and, hence, influence the synthesis of isoprenoid metabolites. It has already been demonstrated that products of the mevalonate pathway play an important role in the progress of the cell cycle and cell survival. Lovastatin (LOV) competitively inhibits HMG-CoA reductase, blocking the synthesis of mevalonic acid and the generation of non-sterol isoprenoids, such as farnesyl residues. The posttranslational farnesylation of p21ras protein is essential for its binding to the membrane and, therefore, for its transforming activity. Considering that p21ras protein was reported to have a significant rol in metastatic behavior of tumor cells, we decided to study LOV as an antimetastatic agent on a rat fibrosarcoma. We demonstrated that a short treatment with LOV diminished primary tumor growth and the number and size of lung experimental metastasis.
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PMID:Lovastatin inhibits tumor growth and metastasis development of a rat fibrosarcoma. 1085 30


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