Enzyme-instructed self-aggregation of Fe3O4 nanoparticles for enhanced MRI T2 imaging and photothermal therapy of tumors.

The aggregation of superparamagnetic iron oxide (SPIO) nanoparticles (NPs) can greatly enhance magnetic resonance imaging (MRI) T2-weighted imaging and near-infrared (NIR) absorption in experiments. In this study, an Ac-Arg-Val-Arg-Arg-Cys(StBu)-Lys-CBT probe was designed and coupled with monodispersed carboxyl-decorated SPIO NPs to form SPIO@1NPs, which use it for intracellular self-aggregation. In vitro experiments showed that the self-aggregation of SPIO@1NPs was induced by a condensation reaction mediated by the enzyme furin in furin-overexpressing tumor cells. Moreover, the NPs in the aggregated state showed significantly higher MR r2 values and photothermal conversion efficiency than the NPs in the monodisperse state. Then, the in vivo SPIO@1NP self-aggregation in tumors can facilitate accurate MRI T2 imaging-guided photothermal therapy for effectively killing cancer cells. We believe that this basic technique, based on tumor-specific enzyme-instructed intracellular self-aggregation of NPs, could be useful for the rational synthesis of other inorganic NPs for use in the fields of tumor diagnosis and treatment.

Integrated computational and Drosophila cancer model platform captures previously unappreciated chemicals perturbing a kinase network.

Drosophila provides an inexpensive and quantitative platform for measuring whole animal drug response. A complementary approach is virtual screening, where chemical libraries can be efficiently screened against protein target(s). Here, we present a unique discovery platform integrating structure-based modeling with Drosophila biology and organic synthesis. We demonstrate this platform by developing chemicals targeting a Drosophila model of Medullary Thyroid Cancer (MTC) characterized by a transformation network activated by oncogenic dRetM955T. Structural models for kinases relevant to MTC were generated for virtual screening to identify unique preliminary hits that suppressed dRetM955T-induced transformation. We then combined features from our hits with those of known inhibitors to create a 'hybrid' molecule with improved suppression of dRetM955T transformation. Our platform provides a framework to efficiently explore novel kinase inhibitors outside of explored inhibitor chemical space that are effective in inhibiting cancer networks while minimizing whole body toxicity.

Matrix metallopeptidase 2 targeted delivery of gold nanostars decorated with IR-780 iodide for dual-modal imaging and enhanced photothermal/photodynamic therapy.

Nanotheranostics has gained increasing interest, as it offers a great potential to realize personalized diagnostics and therapy. In this work, we report a facile approach of the fabrication of gold nanostars (GNS) attached with matrix metalloproteinases (MMP2) polypeptides (Ac-GPLGIAGQ) and IR-780 iodide through bovine serum albumin (BSA) for targeted dual-modal photoacoustic (PA)/near-infrared (NIR) fluorescence imaging and enhanced photothermal therapy (PTT)/photodynamic therapy (PDT) for lung cancer. MMP2 polypeptides served as the targeting ligand, IR-780 iodide functioned as the NIR fluorescence imaging agent as well as PTT/PDT agent, and GNS acted as the carrier of IR-780 molecules and performed PA imaging and PTT. DLS and CCK-8 assay demonstrated that the nanoprobes (GNS@BSA/I-MMP2) exhibited excellent stability and biocompatibility under physiological conditions. Subsequent in vitro studies verified that GNS@BSA/I-MMP2 nanoparticles (NPs) were effectively internalized by A549 cancer cells and exhibited remarkable antitumor efficacy. Furthermore, GNS@BSA/I-MMP2 NPs could specifically target the tumor and significantly suppress the tumor growth, and their antitumor effects were mainly through the synergistic effects of PDT and PTT based on IR-780 and GNS. These findings imply the potential of GNS@BSA/I-MMP2 NPs as a targeting PA/NIR probe in tumor diagnosis and combined therapy with a single light source. STATEMENT OF SIGNIFICANCE: We reported a convenient and facile approach to load IR-780 iodides in gold nanostars (GNS). This material could simultaneously perform near-infrared imaging/photoacoustic imaging and thermotherapy/photodynamic therapy. MMP2 coating on the surface of GNS@BSA/IR-780 promoted the prepared nanoparticles (GNS@BSA/I-MMP2) to target the tumor region. The heat generated by the synergistic effect of the GNS and IR-780 molecules resulted in the high temperature of the GNS@BSA/I-MMP2 NPs, which efficiently suppressed the growth of tumor, and the tumor volume decreased by 93% compared with that in the PBS groups with laser irradiation.

Omega-3 Fatty Acids Prevent Early Pancreatic Carcinogenesis via Repression of the AKT Pathway.

Pancreatic cancer remains a daunting foe despite a vast number of accumulating molecular analyses regarding the mutation and expression status of a variety of genes. Indeed, most pancreatic cancer cases uniformly present with a mutation in the KRAS allele leading to enhanced RAS activation. Yet our understanding of the many epigenetic/environmental factors contributing to disease incidence and progression is waning. Epidemiologic data suggest that diet may be a key factor in pancreatic cancer development and potentially a means of chemoprevention at earlier stages. While diets high in ω3 fatty acids are typically associated with tumor suppression, diets high in ω6 fatty acids have been linked to increased tumor development. Thus, to better understand the contribution of these polyunsaturated fatty acids to pancreatic carcinogenesis, we modeled early stage disease by targeting mutant KRAS to the exocrine pancreas and administered diets rich in these fatty acids to assess tumor formation and altered cell-signaling pathways. We discovered that, consistent with previous reports, the ω3-enriched diet led to reduced lesion penetrance via repression of proliferation associated with reduced phosphorylated AKT (pAKT), whereas the ω6-enriched diet accelerated tumor formation. These data provide a plausible mechanism underlying previously observed effects of fatty acids and suggest that administration of ω3 fatty acids can reduce the pro-survival, pro-growth functions of pAKT. Indeed, counseling subjects at risk to increase their intake of foods containing higher amounts of ω3 fatty acids could aid in the prevention of pancreatic cancer.

The lab oddity prevails: discovery of pan-CDK inhibitor (R)-S-cyclopropyl-S-(4-{[4-{[(1R,2R)-2-hydroxy-1-methylpropyl]oxy}-5-(trifluoromethyl)pyrimidin-2-yl]amino}phenyl)sulfoximide (BAY 1000394) for the treatment of cancer.

Lead optimization of a high-throughput screening hit led to the rapid identification of aminopyrimidine ZK 304709, a multitargeted CDK and VEGF-R inhibitor that displayed a promising preclinical profile. Nevertheless, ZK 304709 failed in phase I studies due to dose-limited absorption and high inter-patient variability, which was attributed to limited aqueous solubility and off-target activity against carbonic anhydrases. Further lead optimization efforts to address the off-target activity profile finally resulted in the introduction of a sulfoximine group, which is still a rather unusual approach in medicinal chemistry. However, the sulfoximine series of compounds quickly revealed very interesting properties, culminating in the identification of the nanomolar pan-CDK inhibitor BAY 1000394, which is currently being investigated in phase I clinical trials.

Cancer-induced anorexia in tumor-bearing mice is dependent on cyclooxygenase-1.

It is well-established that prostaglandins (PGs) affect tumorigenesis, and evidence indicates that PGs also are important for the reduced food intake and body weight loss, the anorexia-cachexia syndrome, in malignant cancer. However, the identity of the PGs and the PG producing cyclooxygenase (COX) species responsible for cancer anorexia-cachexia is unknown. Here, we addressed this issue by transplanting mice with a tumor that elicits anorexia. Meal pattern analysis revealed that the anorexia in the tumor-bearing mice was due to decreased meal frequency. Treatment with a non-selective COX inhibitor attenuated the anorexia, and also tumor growth. When given at manifest anorexia, non-selective COX-inhibitors restored appetite and prevented body weight loss without affecting tumor size. Despite COX-2 induction in the cerebral blood vessels of tumor-bearing mice, a selective COX-2 inhibitor had no effect on the anorexia, whereas selective COX-1 inhibition delayed its onset. Tumor growth was associated with robust increase of PGE(2) levels in plasma - a response blocked both by non-selective COX-inhibition and by selective COX-1 inhibition, but not by COX-2 inhibition. However, there was no increase in PGE(2)-levels in the cerebrospinal fluid. Neutralization of plasma PGE(2) with specific antibodies did not ameliorate the anorexia, and genetic deletion of microsomal PGE synthase-1 (mPGES-1) affected neither anorexia nor tumor growth. Furthermore, tumor-bearing mice lacking EP(4) receptors selectively in the nervous system developed anorexia. These observations suggest that COX-enzymes, most likely COX-1, are involved in cancer-elicited anorexia and weight loss, but that these phenomena occur independently of host mPGES-1, PGE(2) and neuronal EP(4) signaling.

[The induction of Guerin's carcinoma cytochrome p450 hydroxylase activity by retinoids].

The interconnection of tumor growth process and the provision of the body with vitamin A was studied. The replenishment of vitamin A stores of vitamin-deficient tumor bearing animals modulated Guerin's carcinoma growth rate in a dose dependent manner (r = 0,83). The morphological parameters of tumor growth at different provision with vitamin A positively correlated with hydroxylase (r = 0,81) and demethylase (r = 0,49) activities of the Guerin's carcinoma cytochrome P450 system. The induction of hydroxylase and demethylase activities of cytochrome P450 in Guerin's carcinoma microsomal fraction, observed either under conditions of overdose supplementation, or selective liposomal form of all-trans-retinoic acid, suggests the stimulatory effect of retinoids on tumor growth.

Testing of the topoisomerase 1 inhibitor Genz-644282 by the pediatric preclinical testing program.

BACKGROUND: Genz-644282 is a novel non-camptothecin topoisomerase I poison that is in clinical development. PROCEDURES: Genz-644282 was tested against the PPTP in vitro panel (0.1 nM to 1 µM), and in vivo using three times per week × 2 schedule repeated at day 21 at its maximum tolerated dose (MTD) of 4 mg/kg. Subsequently Genz-644282 was tested at 4, 3, 2, and 1 mg/kg in 3 models to assess the dose-response relationship. mRNA gene signatures predictive for Genz-644282 response in vitro were applied to select 15 tumor models that were evaluated prospectively. RESULTS: In vitro, Genz-644282 demonstrated potent cytotoxic activity with a median IC(50) of 1.2 nM (range 0.2-21.9 nM). In vivo, Genz-644282 at its MTD (4 mg/kg) induced maintained complete responses (MCR) in 6/6 evaluable solid tumor models. At 2 mg/kg Genz-644282 induced CR or MCR in 3/3 tumor models relatively insensitive to topotecan, but there were no objective responses at 1 mg/kg. Further testing at 2 mg/kg showed that Genz-644282 induced objective regressions in 7 of 17 (41%) models. There was a significant correlation between predictive response scores based on Affymetrix U133Plus2 baseline tumor expression profiles and the observed in vivo responses to Genz-644282. CONCLUSIONS: Genz-644282 was highly active within a narrow dose range (2-4 mg/kg), typical of other topoisomerase I poisons. As with other topoisomerase I poisons, how accurately these data will translate to clinical activity will depend upon the drug exposures that can be achieved in children treated with this agent.

Initial testing (stage 1) of the mTOR kinase inhibitor AZD8055 by the pediatric preclinical testing program.

BACKGROUND: AZD8055 is a small molecule ATP-competitive inhibitor of the serine/threonine kinase mTOR that regulates cap-dependent translation through the mTORC1 complex and Akt activation through the mTORC2 complex. Procedures AZD8055 was tested against the PPTP in vitro panel at concentrations ranging from 1.0 nM to 10 µM and against the PPTP in vivo panels at a dose of 20 mg/kg administered orally daily x 7 for 4 weeks. RESULTS: In vitro the median relative IC(50) for AZD8055 against the PPTP cell lines was 24.7 nM. Relative I/O values >0% (consistent with a cytostatic effect) were observed in 8 cell lines and 15 cell lines showed Relative I/O values ranging from -4.7 to -92.2% (consistent with varying degrees of cytotoxic activity). In vivo AZD8055 induced significant differences in EFS distribution compared to controls in 23 of 36 (64%) evaluable solid tumor xenografts, and 1 of 6 evaluable ALL xenografts. Intermediate activity for the time to event activity measure (EFS T/C >2) was observed in 5 of 32 (16%) solid tumor xenografts evaluable. The best response was stable disease. PD2 (progressive disease with growth delay) was observed in 20 of 36 (55.6%) evaluable solid tumor xenografts. AZD8055 significantly inhibited 4E-BP1, S6, and Akt phosphorylation following day 1 and day 4 dosing, but suppression of mTORC1 or mTORC2 signaling did not predict tumor sensitivity. CONCLUSIONS: AZD8055 demonstrated broad activity in vitro, but at the dose and schedule studied demonstrated limited activity in vivo against the PPTP solid tumor and ALL panels.

Quantitative determination of decursin, decursinol angelate, and decursinol in mouse plasma and tumor tissue using liquid-liquid extraction and HPLC.

The pyranocoumarin compound decursin and its isomer decursinol angelate (DA) are the major hydrophobic phytochemicals in the root of Angelica gigas Nakai (AGN, Korean Angelica), a major traditional medicinal herb. The ethanol extract of AGN and especially the purified decursin and DA have been shown to exhibit antitumor activities by our collaborative team and others. Although decursinol has been identified as a major hydrolysis metabolite of decursin and DA in vivo in previous pharmacokinetic studies with mouse and rat, other recently published results sharply disputed this conclusion. In this study, we set up a practical method for the concurrent analysis of decursin, DA, and decursinol in mouse plasma and tumor tissues by liquid-liquid extraction and HPLC-UV and applied the method to several animal experiments. Plasma or tumor homogenate was extracted directly with ethyl acetate. The extraction efficiency for decursin/DA (quantitated together) and decursinol was between 82-95 % in both mouse plasma and tumor homogenate. The lower limit of quantitation (LLOQ) was approximately 0.25 µg/mL for decursin/DA and 0.2 µg/mL for decursinol in mouse plasma. In a pilot pharmacokinetic study, male C57BL/6 mice were given a single dose of 4.8 mg decursin/DA mixture (~240 mg/kg) per mouse either by oral gavage or intraperitoneal injection. Maximum plasma concentrations for decursin/DA and decursinol were 11.2 and 79.7 µg/mL, respectively, when decursin/DA was administered via intraperitoneal injection, and 0.54 and 14.9 µg/mL via oral gavage. Decursin/DA and decursinol contents in the tumor tissues from nude mouse xenografts correlated very well with those in plasma. Overall, our results confirm the conclusion that the majority of decursin/DA hydrolyze to decursinol in rodent models with a tiny fraction remaining as the intact compounds administered.

Chemomodulatory potential of Glycine max against murine skin and cervical papillomagenesis.

In the present study, chemopreventive potential of Glycine max (G. Max) seeds was examined against DMBA-induced skin and MCA-induced cervical papillomagenesis in Swiss albino mice. Different doses (2.5, 5, and 7.5% w/w) of G. max were provided to animals in feed. Results exhibited a significant reduction in skin as well as cervical tumor incidence and tumor multiplicity (up to 75%) at all doses of test diet as compared to the control. Relatively, 7.5% test diet was most effective in protecting the animals against carcinogenesis. Further, detoxifying enzymes and antioxidative status was also evaluated in the liver of mice to understand the role of G. max in prevention of cancer. It was observed that the test diet containing G. max significantly elevated the specific activities of glutathione-S-transferase (GST), DT-diaphorase (DTD), superoxide dismutase (SOD), catalase (CAT), and glyoxalase I (Gly I). The test diet also elevated the content of reduced glutathione whereas it decreased the level of the peroxidative damage along with the specific activity of lactate dehydrogenase. It appeared that G. max seeds provided chemoprevention against skin and cervical papillomagenesis probably by modulating the detoxifying and antioxidative enzymes. It could be inferred that intake of G. max might help in reducing the risk of cancer.

RDEA119/BAY 869766: a potent, selective, allosteric inhibitor of MEK1/2 for the treatment of cancer.

The RAS-RAF-mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) kinase (MEK)-ERK pathway provides numerous opportunities for targeted oncology therapeutics. In particular, the MEK enzyme is attractive due to high selectivity for its target ERK and the central role that activated ERK plays in driving cell proliferation. The structural, pharmacologic, and pharmacokinetic properties of RDEA119/BAY 869766, an allosteric MEK inhibitor, are presented. RDEA119/BAY 869766 is selectively bound directly to an allosteric pocket in the MEK1/2 enzymes. This compound is highly efficacious at inhibiting cell proliferation in several tumor cell lines in vitro. In vivo, RDEA119/BAY 869766 exhibits potent activity in xenograft models of melanoma, colon, and epidermal carcinoma. RDEA119/BAY 869766 exhibits complete suppression of ERK phosphorylation at fully efficacious doses in mice. RDEA119/BAY 869766 shows a tissue selectivity that reduces its potential for central nervous system-related side effects. Using pharmacokinetic and pharmacodynamic data, we show that maintaining adequate MEK inhibition throughout the dosing interval is likely more important than achieving high peak levels because greater efficacy was achieved with more frequent but lower dosing. Based on its longer half-life in humans than in mice, RDEA119/BAY 869766 has the potential for use as a once- or twice-daily oral treatment for cancer. RDEA119/BAY 869766, an exquisitely selective, orally available MEK inhibitor, has been selected for clinical development because of its potency and favorable pharmacokinetic profile.

Capsaicin alleviates the imbalance in xenobiotic metabolizing enzymes and tumor markers during experimental lung tumorigenesis.

Lung cancer is currently a leading cause of death all over the world. Environmental risk factors, particularly genotoxic chemicals such as polycyclic aromatic hydrocarbons (PAH), are likely to account for a much higher mortality. Xenobiotic metabolizing enzymes are potentially chief determinants in both the susceptibility to the mutagenic effects of chemical carcinogens and in the response of tumors to chemotherapy. The well-known carcinogen benzo(a)pyrene (B(a)P) of PAH family was given orally (50 mg/kg body weight) to induce lung cancer in Swiss albino mice. B(a)P induction altered the levels of cytochromes (P450, b5), activities of phase I biotransformation enzymes (NADPH-cytochrome P450 reductase, NADH-cytochrome b5 reductase and epoxide hydrolase), phase II enzymes (glutathione-S-transferase, UDP-glucuronyl transferase and DT-diaphorase), and the levels of serum tumor markers. Treatment with capsaicin (CAP) (10 mg/kg body weight) to the lung carcinoma mice restored back the activities of phase I and II biotransformation enzymes and the levels of tumor markers to near normalcy. The above findings were substantiated by immunoblotting and immunohistochemical analysis of cytochrome P450 1A1 (CYP1A1) in the lung tissues. Our present study unravels that CAP can effectively detoxify the carcinogens which discloses its anti-carcinogenic effect during experimental lung cancer.

Anti-cancer activities of pure curry feeding in cancer cell-transplanted mouse.

To confirm the cytotoxic effect of instant curry containing combined spices on cancer cells in vivo, cancer was induced by transplanting cancer cells to mice, and the development of cancer upon feeding pure curry were examined. The concentration of lipid peroxide in the groups transplanted with cancer cells which were fed with normal feed was 19.6 nM, and it was increased as the amount of pure curry was increased. The concentration of cytochrome P-450 was decreased in the group transplanted with cancer cells which were fed with pure curry and the group without the transplant which were fed with pure curry when compared with the groups which were fed with normal feed. The activity of cytochrome P-450 was decreased as the concentration of cytochrome P-450 was decreased in the groups transplanted with cancer cells. However, it was increased in the groups without cancer cell transplant when over 2% of pure curry was fed. The amount of glutathione was increased in the groups transplanted with cancer cells when over 2% of pure curry was fed. The activities of glutathione peroxidase and glutathione S-transferase were decreased in the groups transplanted with cancer cells which were fed with over 1% of pure curry, and were restored to the level of the group without cancer cell transplant which were fed with normal feed. The superoxide dismutase activity in the groups transplanted with cancer cells was restored to the level of the group without cancer cell transplant which was fed with normal feed when over 1% of pure curry was fed.

Inhibition of NF-kappa B activation through targeting I kappa B kinase by celastrol, a quinone methide triterpenoid.

Celastrol, a quinone methide triterpenoid, was isolated as an inhibitor of NF-kappaB from Celastrus orbiculatus. This compound dose-dependently inhibited a variety of stimuli-induced NF-kappa B-regulated gene expression and the DNA-binding of NF-kappa B in different cell lines without affecting DNA-binding activity of AP-1. Preincubation of celastrol completely blocked the LPS-, TNF-alpha-, or PMA-induced degradation and phosphorylation of I kappa B alpha. Importantly, celastrol inhibited IKK activity and the constitutively active IKK beta activity in a dose-dependent manner without either affecting the NF-kappa B activation induced by RelA over-expression or directly suppressing the DNA-binding of activated NF-kappa B. However, mutation of cysteine 179 in the activation loop of IKK beta abolished sensitivity towards to celastrol, suggesting that celastrol suppressed the NF-kappa B activation by targeting cysteine 179 in the IKK. To verify that celastrol is a NF-kappa B inhibitor, we investigated its effect on some NF-kappa B target genes expressions. Celastrol prevented not only LPS-induced mRNA expression of iNOS and TNF-alpha, but also TNF-alpha-induced Bfl-1/A1 expression, a prosurvival Bcl-2 homologue. Consistent with these results, celastrol significantly suppressed the production of NO and TNF-alpha in LPS-stimulated RAW264.7 cells, and increased the cytotoxicity of TNF-alpha in HT-1080 cells. We also demonstrated that celastrol showed anti-inflammatory and anti-tumor activities in animal models. Taken together, this study extends our understanding on the molecular mechanisms underlying the anti-inflammatory and anti-cancer activities of celastrol and celastrol-containing medicinal plant, which would be a valuable candidate for the intervention of NF-kappa B-dependent pathological conditions.

Medicinal chemistry approaches to target the kinase activity of IGF-1R.

Various drug discovery approaches have been explored in recent years to modulate the function of insulin-like growth factor-1 receptor (IGF-1R). This article focuses on the contributions of low-molecular-mass inhibitors in the modulation of IGF-1R kinase activity, and provides an update on recent reviews for this type of agent. Different classes of compounds have been demonstrated to be capable of modulating the kinase activity of IGF-1R in ways that were not possible previously. Preclinical data with some of these inhibitors support the potential application of IGF-1R-targeted therapeutic strategies in the treatment of human cancers.

Modulation of xenobiotic-metabolizing enzymes by ethanolic neem leaf extract during hamster buccal pouch carcinogenesis.

Chemoprevention by medicinal plants is a promising approach for controlling cancer. There is substantial evidence to indicate that chemopreventive agents exert their anticarcinogenic effects by modulation of phase I and phase II xenobiotic-metabolizing enzymes. Therefore, we examined the chemopreventive potential of ethanolic neem leaf extract (ENLE) on 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch (HBP) carcinogenesis. Hamsters were divided into four groups of six animals each. The right buccal pouches of animals in Group I were painted with 0.5 per cent DMBA in liquid paraffin three times per week. Animals in Group 2 painted with DMBA as in group 1, received in addition, intragastric administration of ENLE at a concentration of 200 mg/kg bw three times per week on days alternate to DMBA application. Group 3 was given ENLE alone. Animals in Group 4 served as controls. All animals were killed after an experimental period of 14 weeks. Five out of six hamsters painted with DMBA alone developed squamous cell carcinomas in the buccal pouch. The HBP tumours showed an increase in phase I carcinogen activation (cytochrome P450 and b5) and phase II detoxification enzyme (glutathione-S-transferase, DT-diaphorase and NADPH-diaphorase) activities. In the liver of tumour-bearing animals, enhanced cytochrome P450 and b5 levels were accompanied by a decrease in phase II detoxification enzyme activities. Administration of ENLE effectively suppressed DMBA-induced HBP tumours, decreased cytochrome P450 and b5 levels, and enhanced phase II enzyme activities in the pouch and liver. Our results suggest that the modulation of DMBA metabolism is a possible mechanism for the chemopreventive effects of ethanolic neem leaf extract.

Galactosyltransferase associated with tumor in patients with ovarian cancer: factors involved in elevation of serum galactosyltransferase.

The serum level of beta1,4-galactosyltransferase (beta1,4-GalT) is increased in both malignancy and benign diseases. Galactosyltransferase associated with tumor (GAT) is one of the soluble forms of beta1,4-GalT, and is a marker of ovarian cancer with a high specificity. GAT and normal soluble beta1,4-GalT are both derived from the same membrane-bound form of the enzyme. This study investigated the mechanism of GAT elevation in patients with ovarian cancer. The serum levels of GAT and normal beta1,4-GalT were measured using specific monoclonal antibodies. In addition, nude mice bearing human ovarian cancer were used to assess the kinetics of tumor-derived enzymes. GAT and normal beta1,4-GalT were both detected in ovarian cancer patients, but only GAT reflected the tumor status. In tumor-bearing nude mice, both soluble forms of beta1,4-GalT were released from tumor cells, but the half-life of GAT was far shorter than that of normal beta1,4-GalT. Addition of serum from healthy women to colostrum (which has a high GAT content) reduced the GAT level, while adding patient serum caused a significantly smaller reduction of GAT. Addition of the serum from mouse which includes no human beta1,4-GalT to colostrum also reduced the GAT level with no significant change of total soluble beta1,4-GalT. These findings indicate that human serum contains certain factors that decrease the GAT level, but these factors are inhibited in ovarian cancer patients so that a high GAT level persists. It seems that the decrease of GAT occurs as a result of conversion into normal beta1,4-GalT.

Combined supplementation of vanadium and 1alpha,25-dihydroxyvitamin D3 inhibit placental glutathione S-transferase positive foci in rat liver carcinogenesis.

The combined effects of vanadium (V) and 1alpha,25-dihydroxyvitamin D3 [1,25(OH)2D3] in inhibiting diethylnitrosamine (DEN)-induced and phenobarbital (PB) promoted hepatocarcinogenesis were examined in male Sprague-Dawley rats. All the rats were subjected to 70% partial hepatectomy (PH) at week 4 and 24h later were administered either solvent trioctanoin (Group B, D, F and H) or 10 mg DEN/kg (Group A, C, E and G) by gavage. Briefly after two weeks of DEN administration, PB were administered (0.05% in basal diet) to all the DEN-treated rats and continued till the completion of the experiment. Supplementary V at the dose of 0.5 ppm in drinking water ad libitum (Group C and D), 1,25(OH)2D3 at the dose of 3 microg/ml in propylene glycol per os twice a week (Group E and F) or both V and 1,25(OH)2D3 at the same above given doses (Group G and H) were started 4 weeks prior to DEN administration (week 0) and continued thereafter till week 15. The expression of the number and area of altered hepatocyte foci (AHF) positive for placental glutathione S-transferase (GST-P) was maximum in DEN-treated and PB promoted group (Group A). V (Group C) and 1,25(OH)2D3 (Group E) treatment significantly reduced the expression of GST-P-positive hepatocytes by 36.02% and 45.16% respectively but an additive protective action (61.46%) was found in Group G which received both V and 1,25(OH)2D3 for the entire period of the study. Moreover, histopathological examination and the incidence of hepatic hyperplastic nodules showed that combined action of V and 1,25(OH)2D3 can able to minimize the appearance of nodules as well and maintain the normal cellular architecture than V and 1,25(OH)2D3 when given alone. These results suggest that, when given together V and 1,25(OH)2D3 could be the chemopreventive agents for rat liver carcinogenesis.