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Grapes and grape extracts were compared for inhibition of a growth-related and cancer-specific form of cell surface NADH oxidase with protein disulfide-thiol interchange activity designated tNOX from human cervical carcinoma (HeLa) cells and growth of HeLa and mouse mammary 4T1 cells in culture and transplanted tumors in mice. Grapes and grape extracts of several varieties had activity. With an extracted grape preparation provided by the California Table Grape Commission, an active fraction was eluted with methanol from a Diaion HP-20 column after removal of inactive water-soluble materials. Grape skins were a much more potent source than either grape pulp, juice or seeds. Ethanol extracts of the ground freeze-dried pomace was an excellent source. The grape extracts interacted, often synergistically, with decaffeinated green tea extracts both in the inhibition of tNOX activity and in the inhibition of cancer cell growth. Intratumoral injections of a 25:1 mixture of a green tea extract plus ground freeze-dried pomace was nearly as effective as standard synergistic green tea–Capsicum mixtures in inhibiting growth of 4T1 mammary tumors in situ in mice.

One of the most promising substances used in photodynamic therapy (PDT) is 5-aminolevulinic acid (ALA), which induces endogenous synthesis and accumulation of porphyrins in malignant cells. In this paper we have shown that both topical and intratumoral administration of ALA in a subcutaneously implanted mammary carcinoma produced a significant synthesis of porphyrins and subsequent sensitization to laser light. Porphyrin accumulation was greater when ALA was administered intratumorally and tumour/normal skin porphyrin concentration ratios were higher compared with topical application. Irradiation was optimal between 2 and 3 h after topical application of 50 mg of a 20% ALA cream and 2–4 h after intratumoral administration of 30 mg ALA/cm3. The pattern of tumour response evaluated as the delay of tumour growth was similar following either route of drug administration. Applications of PDT were performed once, twice or three times in the study. The response to successive applications was constant for the same tumour, indicating that no resistance was acquired. Microscopic analysis showed both induction of foci of necrosis and haemorrhage, morphological features of apoptotic cells and total absence of cellular immune response. This paper reports on PDT with topical ALA in a subcutaneous carcinoma leading to tumour growth delay. These findings may have great relevance in the treatment of cutaneous metastasis of mammary carcinomas.

Despite the clinical success of immune checkpoint blockade, only a subset of people exhibits durable responses, suggesting that an alternative immunotherapeutic strategy is required. This paper reported a two-in-one cancer vaccine that targets programmed death ligand 1 (PDL1) that blocks the PD1/PDL1 pathway and also activates antitumor immune response. The PDL1- NitraTh vaccine, which consists of the extracellular domain of PDL1 and nitrated T cell epitope, effectively broke the immune tolerance of PDL1 and elicited PDL1-specific humoral and cellular immunity. The treatment of PDL1-NitraTh exhibited potent antitumor activity. Moreover, immunization of PDL1 vaccine increased the infiltration of tumor lymphocytes and decreased the proportion of Treg cells in tumor tissues, suggesting that the vaccine may remodel the tumor microenvironment. The upregulation of PDL1 in tumor tissues was induced by PDL1-NitraTh vaccine but not in spleen and lymphomas. This upregulation of PDL1 is beneficial to the antitumor activity of PDL1-specific humoral and cellular immunity induced by PDL1-NitraTh. In summary, PDL1-targeted vaccine exhibits potent antitumor activity and may provide an alternative immunotherapy strategy for patients who are not sensitive to PDL1 antibody drugs.

Osteosarcoma (OS) is the most frequent paediatric bone cancer, responsible for 9% of all cancer-related deaths in children. In this paper, a new strategy based on delivering edelfosine (ET) in lipid nanoparticles (LN) was explored in order to target the primary tumour and eliminate metastases. The in vitro and in vivo efficacy of the free drug, drug loaded into lipid nanoparticles (ET-LN) and doxorubicin (DOX) against osteosarcoma (OS) cells was analysed. ET and ET-LN decreased the growth of OS cells in vitro in a time- and dose-dependent manner. Interestingly, the uptake of ET and ET-LN was lower when OS cells were pre-treated with DOX. In vivo studies revealed that ET and ET-LN slowed down the primary tumour growth in two OS models. However, the combination of both drugs showed no additional anti-tumour effect. Importantly, ET-LN successfully prevented the metastatic spread of OS cells from the primary tumour to the lungs. On the whole, ET-LN are a promising candidate for OS chemotherapy.

The recent demonstration of a role of Escherichia coli in the development of invasive carcinoma in mice ushers a new era of bacterial involvement in cancer etiology. It has been shown previously that the colonic mucosa of colorectal carcinoma (CRC) is exclusively colonized by intracellular E. coli instead of extracellular form found in normal colonic mucosa. Surprisingly, the DNA repair gene MUTYH, which is a homologue of the E. coli gene mutY, is responsible for CRC. The current paper discusses the potential role of mutY in CRC etiology and concludes that research in this area can bring together the diverse threads of the CRC etiology puzzle.

Gene therapy is an important means for the comprehensive treatment of pancreatic cancer. Challenges associated with gene therapy include control of vector security and effective genetic screening. In this paper, a CEA promoter-regulated oncolytic adenovirus vector was constructed. The reporter gene assay demonstrated that the viral vector was confirmed to have tumor-specific replication features. In vitro cytology studies showed that the CEA promoter regulated the proliferation of the adenovirus vector carrying the Hsp70 gene (AdCEAp-Hsp70), which significantly increased the expression levels of Hsp70 in the CEA-positive pancreatic cancer cells, resulting in an overall reduction in the survival of cancer cells. In the human pancreatic cancer Panc-1 xenograft model in immune deficient nude mice, the CEA promoter-regulated adenovirus AdCEAp-Hsp70 significantly inhibited tumor growth. In the rat pancreatic cancer DSL-6A/C1 xenograft model in rats, the viral proliferation and high expression levels of Hsp70 promoted the interstitial infiltration of CD4+, CD8+ and gamma/delta T cells into tumors, induced host secretion of the cytokines TGF-β, INF-γ, and IL-6 and had a dual anti-tumor effects that completely inhibited the growth of pancreatic cancer. The results demonstrated that the oncolytic adenovirus under the control of CEA promoter provides additional assurances regarding the safety and efficiency of cancer gene therapy. This gene therapy model improves anti-cancer efficiency and has broad applications and developmental prospects.

Cancer stem cell (CSC) is generally believed to be a very small proportion of tumor cells capable of initiating and sustaining growth of the tumor. Its existence is usually demonstrated by xenotransplanting human cancer cells in immunodeficient mice. In this paper, we report that the growth of B16-F10 melanoma cells in syngeneic mice could be maintained by a relatively larger proportion (>10%) of tumor cells. The result of this study does not seem to support the current view that cancer stem cells (CSCs) responsible for the sustainable growth of tumor are rare.

Matrix metalloproteinases (MMPs) are believed to play a pivotal role in malignant behavior of cancer cells such as rapid tumor growth, invasion, and metastasis by degrading extracellular matrix (ECM). Different types of synthetic inhibitors against MMPs (MMPIs) were developed as candidates for anti-cancer therapeutics and so far clinical trials had led to no significant success. However, this does not diminish the importance of MMPs in the malignancy of cells. Details about MMPs, specifically when and how they take part in the development of cancer are necessary for more advanced application of MMPIs. In this paper, we summarize recent knowledge about membrane-type 1 matrix metalloproteinase (MT1-MMP) which is expressed on cancer cell surface as an invasion-promoting proteinase. By localizing at the leading edge of invasive cancer cells, MT1-MMP degrades components of the tissue barriers. One of the major targets is type I collagen, the most abundant ECM component. Although MT1-MMP itself cannot degrade type IV collagen in the basement membrane, it binds to and activates proMMP-2, one of the type IV collagenases. However, degradation of the ECM is not the sole function of MT1-MMP. MT1-MMP also regulates cell-ECM interaction by processing cell adhesion molecules such as CD44 and integrin αv chain, and eventually promotes cell migration as well. In addition to the transcriptional regulation, invasion-promoting activity of the MT1-MMP is also strictly monitored at the post-translational level. Precise knowledge about the regulation will give us insight to develop new methods for treating invasive cancer patients.

This paper reports on studies that evaluate the interaction between delta-aminolevulinic acid (ALA)-based photodynamic therapy (PDT) and adriamycin (ADM) in an animal model system. Two groups of mice bearing a transplantable mammary adenocarcinoma received ADM i.p. in a single dose of 5 mg (low dose) and 30 mg (high dose) per kg body weight. Sixteen or 40 h after administration of the drug, mice were sacrificed, tumours, livers and hearts were removed and porphyrins, enzyme activities and malondialdehyde content were determined. Tumour explants of ADM-treated mice were incubated with ALA and irradiated with an He-Ne laser. Re-implantation of these in vitro PDT-treated explants into test animals showed that inhibition of tumour growth was significantly enhanced by combined treatment when the low dose of ADM was used. There were no significant changes in porphyrin content, ALA dehydratase and porphobilinogenase activities in the tissues analyzed after ADM treatment as compared with control values. ADM toxicity is thought to be related to semiquinone free radical formation with subsequent generation of reactive oxygen species such as peroxide and hydroxyl radical. These species are considered to initiate lipid peroxidation (LPO) and cause DNA damage. In the case of low-dose treatment with ADM a significant increase in the LPO product, malondialdehyde, was observed after PDT whereas with the high-dose regimen no changes were observed. In the case of explants of (non-irradiated) cardiac tissue malondialdehyde production was also found to be dependent on the dose and time of administration of adriamycin. In our in vivo/in vitro model system we have shown that pre-treatment with ADM increased the cytotoxicity of ALA-PDT at a dosage level of ADM which did not raise LPO levels in heart tissue. The mechanism of this effect has not been clearly elucidated but our data suggest that the observed enhancement of PDT may be attributed in part to the weakening of cellular defence mechanisms by the pre-treatment involving free radical generation by ADM.

B16 melanoma has proved to be an ideal model for investigating metastasis. The parental B16F1 line grows as a localized subcutaneous tumor in C57BL/6 or DBA/2 mice. However, by means of successive intravenous transplantation, a subline B16F10 has been established. This shows preponderant lung homing when transplanted by intravenous route into C57BL/6 mice. In this paper we have shown that pentoxifylline (PTX; Hoechst), a microfilament depolymerising agent can inhibit significantly this lung homing of B16F10 cells. It also had a marginal inhibitory effect on subcutaneous tumor growth.

Increased protein synthesis is necessary for the transition of cells from quiescence to proliferation. It is shown in this paper that the induction of expression of the translation initiation factor eIF-4E in normal cells requires serum growth factors, while this requirement is abrogated in tumor cells analyzed in this study. Further, the expression of eIF-4E and eIF-2alpha is increased in c-myc, v-src, and v-abl-transformed cells. It is demonstrated that an increase in c-myc function leads to elevated expression of eIF-4E and eIF-2alpha, increases in net protein synthesis and cell proliferation. It may be suggested that constitutive activation of translational machinery may be one common mechanism by which various oncogenes exert their transforming function.

This paper assesses the modificatory potential of arecanut ( Areca catechu L.), a popular masticatory substance, on 2(3)- tert -butyl-4-hydroxy anisole (BHA)-induced changes in the hepatic detoxification system and antioxidant defence mechanisms in mice. The modulatory effects on biochemical parameters including glutathione S-transferase (GST), cytochrome b 5 , cytochrome P-450, acid soluble sulfhydryl (−SH) content and microsomal lipid peroxidation (MDA) levels were assessed. Mice were fed either a normal diet or diets containing 0.25%, 0.5% or 1% (w/w) arecanut for 45 days. During the last 10 days of treatment the feed was supplemented with 0.5% or 1% BHA. Inclusion of BHA in the diet significantly modulated the detoxification system enzymes, −SH content and malondialdehyde (MDA) levels in the liver of the mice. BHA-induced alterations in hepatic GST and −SH content were depressed while cytochrome b 5 , cytochrome P-450 and MDA levels were further elevated by the arecanut treatment.

The present paper deals with the modulatory influence of camphor on the activities of hepatic phase I and phase II drug metabolising enzymes and the levels of hepatic and extrahepatic reduced glutathione contents in the mouse. Female Swiss albino mice (8-9 weeks old) were treated daily by oral route for 20 days with 50, 150 or 300 mg/kg body weight of camphor dissolved in 0.1 ml of olive oil. Camphor only at the 300 mg/kg body weight dose level caused a significant increase in the activities of cytochrome P450 (P < 0.05), cytochrome b5 (P < 0.05), aryl hydrocarbon hydroxylase (P < 0.05) and glutathione S-transferase (P < 0.05). These modulatory effects were comparable with those induced by 0.75% BHA diet given for 20 days (positive control group). The reduced glutathione level was elevated significantly in liver (P < 0.05) by camphor only at the 300 mg/kg body weight dose level and in liver, lung and stomach (P < 0.05) by BHA.

Our previous studies have resulted in the identification and cloning of int-5 , a novel site of mouse mammary tumor virus (MMTV) integration, from BALB/c D2 precancerous hyperplastic alveolar nodules (HAN). This paper presents a detailed characterization of the int-5 locus from both D2 HAN and normal genome and expression of the unique gene from the MMTV integration site. Our results show that the cellular gene at the MMTV integration site in the int-5 locus is identical to the gene encoding aromatase (CYP19), a member of the cytochrome P -450 gene superfamily. MMTV is integrated within exon 10 in the 3′ untranslated region of the aromatase gene. This gene ( int-5/aromatase ) is expressed in normal mammary gland and overexpressed in mammary tumors. These results suggest that the overexpression of this gene may be responsible for mammary tumorigenesis. This is the first demonstration of integration of MMTV in a cellular gene that plays a role in hormone-dependent breast cancers.

The present paper assesses the modifying potential of black pepper on the hepatic biotransformation system in mice. The modulatory effect was assessed on glutathione S -transferase (GST), cytochrome b 5 (cyt. b 5 ), cytochrome P-450 (cyt. P-450), acid-soluble sulfhydryl (-SH) content and malondialdehyde (MDA) level. Swiss albino mice of either sex (eight weeks old) were fed on a diet containing 0.5%, 1% and 2% black pepper (w/w) for 10 and 20 days. The findings revealed a significant and dose-dependent increase in GST and -SH content in the experimental groups except the one maintained on 0.5% black pepper diet for 10 days. Elevated levels of cyt. b 5 and cyt. P-450 were also statistically significant and dosedependent. The level of MDA was lowered in the group fed on 2% black pepper diet for 20 days. Being a potential inducer of detoxication system, the possible chemopreventive role of black pepper in chemical carcinogenesis is suggested.

Doxycycline has been found to induce apoptosis and to inhibit the growth of a variety of tumor cells, in addition to its use as an antibiotic. However, the mechanism of its actions, especially at the molecular level, remains unknown and needs to be resolved. A crucial step possibly lies in the early period of doxycycline administration, which leads to a series of cascading effects depicting the consequential biological action of doxycycline on tumor cells. The present study focuses on the early-stage effects of doxycycline administration, specifically at the stages of treatment (before 16h). In this paper, we report that doxycycline inhibits the adhesion and migration of melanoma cells. Afterwards, the cells undergo apoptosis (aniokis). Remarkably, doxycycline also inhibits the expression and phosphorylation of focal adhesion kinase (FAK), a protein tyrosine kinase involved in the regulation of cell adhesion and migration. We further demonstrate that doxycycline down-regulates the activities of MMP-2 and MMP-9, and its effects are stronger than those of an Integrin beta1 antibody. Finally, we suggest that doxycycline might exert its anti-tumor effects by inhibiting FAK signaling pathway. These results provide an insight into the possible mechanisms that underlie the multiple drug actions of doxycycline. The potential use of doxycycline in anti-tumor treatment is promising and warrants further studies.

In vivo rodent cytogenetics may provide an important basis for an animal model for the assessment of the carcinogenic potential of antitumor drugs in man. In this paper, genotoxic alterations (i.e. sister chromatid exchanges and micronuclei) caused by different cytostatic protocols in CBA/Ca mice are described. The strongest sister chromatid exchange inducing effects were shown by the ABVD (doxorubicin-dacarbazine-bleomycinvinblastine) group and combinations containing cyclophosphamide. Compounds which affect the mitotic spindle induced only micronuclei, but not sister chromatid exchanges.

Since multicellular resistance (MCR) has been shown to be as adhesion-dependent, the role of alphav integrin in MCR of HT29 was investigated in this paper. Down-regulation of alphav integrin reduced MCR to oxaliplatin, but did not detectably change the drug sensitivity of monolayers. Down-regulation of alphav integrin decreased phosphorylated NF-kappaB p65 and increased phosphorylated JNK2 in multicellular spheroids. Cell-cell adhesion and cell-cell junctions in multicellular spheroids resembled the in vivo situation. Since force, including adhesion, can activate alphav integrin, cell-cell contact may contribute to activation of alphav integrin, through which increasing phosphorylated p65 and decreasing phosphorylated JNK2 takes part in MCR.

The protective role of estrogens in the colon carcinogenesis has been suggested for many years and attributed mainly to estrogen receptor beta (ERbeta). However, the direct effect of estrogens and their action through ERbeta on the growth of colon cancer have been rarely studied. The aim of this study was to examine the effect of various concentrations (10(-4)-10(-12)M) of diarylpropionitrile (DPN)--a selective agonist of ERbeta--on the growth of murine MC38 colon cancer line. Moreover, the aim of this paper was the immunohistochemical assessment of estrogen and progesterone receptor expression in human colon tissues and in MC38 cells (only ERbeta). We found that DPN induced a growth inhibition of MC38 cancer (50-94% of control group) at the highest (10(-4)M) and two lowest concentrations (10(-11) and 10(-12)M). Furthermore, we detected a nuclear-cytoplasmic expression of ERbeta in human normal and neoplastic colon tissues and in the studied MC38 cancer cells. The inhibitory effect of DPN on the growth of MC38 colon cancer line suggests a possibility of using a selective estrogen receptor agonist in the treatment of colon cancer.

Recombinant interferon-gamma (rIFN-gamma) is currently undergoing clinical trials in cancer patients. In this paper, we assessed the in vivo antitumor effects of this lymphokine in rodents. Recombinant murine IFN-gamma or control medium was injected intraperitoneally for 5 days into mice with subcutaneous Meth A tumors. An injection of a suboptimal dose of endotoxin (2 micrograms) on the fifth treatment day caused significant necrosis of tumors in the IFN-gamma-treated group while causing essentially no necrosis of tumors in the control group. Next, we examined macrophages isolated from rats treated for 9 days with either IFN-gamma or saline. Endotoxin stimulated release of significantly higher amounts of TNF-alpha from macrophages from the IFN-gamma-treated group compared to macrophages from the control group. A polyclonal antiserum against recombinant murine TNF-alpha abrogated all of the TNF cytotoxic activity from these rat macrophage supernatants, while control rabbit serum had no effect. These results provide strong evidence that rIFN-gamma can prime macrophages in vivo for TNF-alpha synthesis.

The present paper reports the chemopreventive action of garlic on 3-methylcholanthrene (MCA)-induced carcinogenesis in the uterine cervix of virgin young adult Swiss albino mice. Insertion of sterile cotton thread impregnated with beeswax containing approximately 600 micrograms of MCA inside the canal of uterine cervix results in the appearance of precancerous and cancerous lesions in the cervical epithelium. In this experimental cervical carcinogenesis model system, if garlic was administered orally at the dose level of 400 mg/kg body wt./day for 2 weeks before and 4 weeks following carcinogen thread insertion. The cervical carcinoma incidence, as compared with that of the positive control (73%), was 23%. This decline in the incidence of carcinoma was highly significant (P less than 0.01). Hyperplastic and dysplastic changes did not show any definite correlation with the garlic treatment.

Viscum album (Mistletoe) is one of the most widely used alternative cancer therapies. Aqueous mistletoe extracts (MT) contain the three mistletoe lectins I, II and III as one predominant group of biologically active agents. Although MT is widely used, there is a lack of scientifically sound preclinical and clinical data. In this paper, we describe for the first time the in vivo efficacy and mechanism of action of MT in lymphoblastic leukemia. For this purpose, we first investigated both the cytotoxic effect and the mechanism of action of two standardized aqueous MTs (MT obtained from fir trees (MT-A); MT obtained from pine trees (MT-P)) in a human acute lymphoblastic leukemia (ALL) cell line (NALM-6). MT-A, MT-P and ML-I inhibited cell proliferation as determined by Casy® Count analysis at very low concentrations with MT-P being the most cytotoxic extract. DNA-fragmentation assays indicated that dose-dependent induction of apoptosis was the main mechanism of cell death. Finally, we evaluated the efficacy of MT-A and MT-P in an in vivo SCID-model of pre-B ALL (NALM-6). Both MTs significantly improved survival (up to 55.4 days) at all tested concentrations in contrast to controls (34.6 days) without side effects.

Treatment of estrogen-sensitive breast cancer with selective estrogen selective modulators (SERMs) and, more recently, aromatase inhibitors has met with wide success. However, antagonism of estrogen receptor (ER) activity in breast carcinomas by SERMs such as tamoxifen has been associated with increased risk of cancer in other tissue such as the endometrium. Furthermore, current therapies using aromatase inhibitors have side effects on bone resulting in development of osteoporosis in some patients. We present in this paper the results of a study using 4-chlorophenylacetate (4-CPA), a compound which belongs to a family of small aromatic fatty acids that has been shown to possess anticancer properties, to treat DMBA exposed MMTV-aromatase mice. These animals exhibit elevated levels of estrogen in their mammary glands and develop estrogen-responsive tumors. Consistent with our earlier findings showing that 4-CPA inhibited the growth of ER positive breast cancer cells in vitro, we now demonstrate that this compound inhibits tumor formation in MMTV-aromatase mice. This effect was not associated with reduction of ER expression in their mammary tissue, or to alteration of aromatase levels or activity. The data suggest that 4-CPA is a novel therapeutic agent that could be used in the prevention or treatment of estrogen-sensitive breast cancer.

The transcription factor NF-kappa B is constitutively activated in many human cancers, and induces the expression of multiple proteins including antiapoptotic proteins. Recent papers indicate that NF-kappa B activation is inhibited by interleukin (IL)-10. In this study, we investigated the effect of IL-10 plasmid DNA on colon cancer in mice. In vitro study: Colon 26 murine colon adenocarcinoma cells were either treated or untreated with IL-10 for 60 min. The cells were subsequently stimulated with TNF-alpha. In vivo study: to induce a high level of IL-10 in plasma, we transferred the naked plasmid vectors encoding the mouse IL-10 gene into the liver via the intravenous route. To establish tumors, we injected Colon 26 cells into BALB/c mice subcutaneously. In vitro study: a 24-h incubation with TNF-alpha did not affect cell viabilities; however, pretreatment with IL-10 significantly enhanced the level of apoptosis induced by TNF-alpha. Pretreating Colon 26 cells with IL-10 significantly attenuated the TNF-alpha-induced NF-kappa B activation. In vivo study: IL-10 plasmid controlled the growth of subcutaneous tumors. In subcutaneous tumor, NF-kappa B was activated in response to tumor growth. IL-10 plasmid markedly inhibited this activation of NF-kappa B in subcutaneous tumor. IL-10 plasmid induced cancer cell apoptosis linked to the down-regulation of antiapoptotic proteins, and the activation of caspase-3. These results demonstrate that IL-10 plasmid may constitute a new strategy for treating cancer growth.

Human mammary epithelial cells (HMEC) were immortalized by serial passaging through senescence (M0) and subsequent transduction with the catalytic subunit of the human telomerase gene (hTERT). These cells acquired multiple non-random cytogenetic abnormalities with lengthy passaging in vitro, but are still not tumorigenic in irradiated nude mice and cannot grow in soft agar. Transduction, of late passage immortal HMEC from a single donor, with a retroviral vector containing the mutant autoactive H-Ras 61L gene, enabled immortal HMEC to acquire anchorage independent growth properties. Three colonies were picked and all three were found to be tumorigenic. One colony exclusively produced epithelial tumors in nude mice, but the other two colonies gave rise exclusively to malignancies in which the cells displayed a spindle morphology. In this paper we describe the characteristics of the tumors arising from one of these ‘spindle colonies’. These tumors were strongly positive for vimentin staining and virtually negative for pan-cytokeratin staining, on immunohistochemistry. Cytogenetic analysis of the cells derived from these tumors confirmed that they were derived from the original cultured, immortalized mammary cells. We conclude that the HMEC have undergone metaplastic transformation due to the high levels of H-Ras 61L and telomerase activity that they display, and the derived tumors are best described as spindle cell carcinomas.

The drs gene was isolated as a transformation suppressor against the v-src oncogene. Drs protein has a transmembrane domain and three consensus repeats (CRs) called Sushi motifs in the extracellular domain. The drs gene also has the ability to suppress anchorage-independent growth of human cancer cell lines. In this paper, we report the isolation of a novel variant cDNA of mouse drs (mDRS-2) containing two CRs, in addition to a mouse homolog of drs (mDRS-1) containing three CRs. We investigated the suppressor function of these mDRS cDNAs in human cancer cells and found that the lack of one CR is critical for suppression of anchorage-independent growth by drs.

In this paper we describe the chemical procedure of fibrinogen-methotrexate (F-MTX) conjugate preparation and its in vitro and in vivo antitumor activity. F-MTX conjugates were synthesized in reaction of fibrinogen with MTX N-hydroxysuccynimide ester. The conjugates were not cross-linked and were soluble in water. The results of the in vitro and in vivo studies have shown: (1) a lower in vitro cytotoxicity of the F-MTX conjugate as compared with MTX alone; (2) a significantly higher in vivo antitumor activity of the F-MTX conjugate in mice with P388 leukemia as compared with MTX alone; (3) a significantly increased in vivo lethal toxicity of F-MTX as compared with MTX. The results suggest the therapeutic utility of the fibrinogen-methotrexate conjugate and the usefulness of fibrinogen as a chemotherapeutic drug carrier. However, a new effort in the preparation of F-MTX conjugate should be made to decrease its in vivo toxicity.

In previous papers we have demonstrated that sialoadenectomy inhibited MPA-induced mammary tumorigenesis in BALB/c mice. To further explore the role of EGF in this experimental model, we evaluated its effects on mammary glands of sialoadenectomized (sialox) MPA-treated female mice and on tumor growth. MPA-treated sialox mice were injected s.c. (n = 3) or not (n = 6) with 5 microg EGF every 36 h for 45 days; MPA-treated sham-operated mice were used as controls (n = 6). Mammary glands from sialox MPA-treated mice are considerably less developed as compared with sham-operated animals. The exogenous administration of EGF restores the usual MPA-induced growth pattern of the glands, thus confirming a role for EGF either in mediating or cooperating with MPA in inducing the mammary architectural changes observed in MPA-treated mice. On the other hand, primary cultures of progestin-dependent (PD) ductal mammary adenocarcinoma in vivo tumor lines and of lobular progestin-independent (PI) tumor lines were used to evaluate the effect of EGF on tumor growth. In vitro EGF was found to stimulate cell proliferation of lobular PI tumor cells and of fibroblastic cells from both types of tumors at concentrations higher than 0.1-0.5 ng/ml and in the presence of 1-5% of charcoal-stripped fetal calf serum. Conversely, no proliferative effects were observed in ductal PD cells under the same experimental conditions, regardless of the presence of 10 nM MPA. It can be concluded that although EGF plays an important role in MPA-induced mammary carcinogenesis, it is not necessary in PD tumor growth.

Activation of protein synthesis is necessary for the transition of cells from quiescence to proliferation, while withdrawal of growth factors leads to decrease in protein synthesis and transition of normal cells into the resting period. It is shown in this paper that serum growth factors are required for activation of expression of gene encoding translation initiation factor 4E (eIF-4E) in non-transformed NIH 3T3 and Rat-1 fibroblasts but this requirement is lost in C6 glioblastoma, A431 carcinoma and N-myc transformed Rat-1 cells. These data raise the possibility that neoplastic transformation leads to growth factor-independent expression of eIF-4E, thus facilitating continuous growth and replication of transformed cells.

The current standard approach for assessing carcinogenic potential is to conduct a near lifetime rodent pathology study with the high dose set to the maximum tolerated dose (MTD) of the test chemical. The linearized multistage model is then used as the default approach to estimate the potential human cancer risk at environmental levels of the chemical. There is an increasing appreciation in the scientific and regulatory communities that chemical carcinogens differ dramatically in potency, exhibit a high degree of tissue and species specificity, and act through different modes of action. This paper advocates a decision tree strategy for classifying carcinogens that are acting primarily through genotoxic, cytotoxic, or mitogenic pathways. A primary concern is whether the chemical has direct genotoxic potential resulting from DNA reactivity or clastogenicity of the compound or its metabolite(s). Knowledge of the exposure-response curve for cytotoxicity is important because initiation and promotion events may occur secondary to a variety of associated activities such as regenerative cell proliferation. Mitogens induce direct stimulation of growth and may provide a selective growth advantage to spontaneously initiated precancerous cells. Of particular concern is the situation where pathological changes induced during the course of the treatment at high doses near the MTD are absent at lower, environmentally relevant, doses. If the tumor response is coincident with the preceding toxic response, it may not be justified to use the high-dose data in extrapolating to expected responses at low environmental exposures where no induced tissue abnormalities occur. Suggestions are presented for appropriate risk assessment approaches for different modes of action. Examples discussed are formaldehyde, a weakly genotoxic rodent nasal carcinogen; chloroform, a nongenotoxic-cytotoxic rodent liver and kidney carcinogen; and phenobarbital, a nongenotoxicmitogenic rodent liver carcinogen.

Our recent studies have shown that the cellular gene at the mouse mammary tumor virus (MMTV) integration site in the int-5 locus in BALB/c D2 precancerous hyperplastic alveolar nodules is identical to the gene encoding aromatase (CYP19), a member of the cytochrome P450 gene superfamily. MMTV integrated within the 3′ untranslated region of the aromatase gene is responsible for the overexpression of this gene ( int-5/aromatase ) in mammary tumors. This paper describes the biological significance of overexpression of int-5/aromatase in D2 tumor cells. Using a cell line derived from the D2 tumor, we have demonstrated the effect of the aromatase substrate, androstenedione, on the proliferation of tumor cells. Proliferative effects of androstenedione were blocked by an aromatase inhibitor, providing evidence for the role of int-5/aromatase in this process. Furthermore, the androstenedione-mediated proliferation was inhibited by the addition of anti-estrogen ICI 164,384, suggesting that the estrogen formed from the conversion of androstenedione by int-5/aromatase acts like a mitogen to stimulate the growth of D2 tumor cells. This model with its known mechanism of aromatase activation should prove useful for studying the role of intra-tumoral estrogen in mammary cancer, for evaluating the effects of aromatase inhibitors, and for comparing breast cancer treatments.

The present paper reports the chemopreventive property of mace (aril covering the seed of Myristica fragrans) on DMBA-induced papillomagenesis in the skin of male Swiss albino mice. When a single topical application of DMBA (150 micrograms in 100 microliters of acetone) was followed, 2 weeks later, by repeated applications of croton oil (1% in acetone, three times/week) skin papillomas appeared in 100% animals and the average tumors per tumor-bearing animal was 5.67. On the other hand, when animals receiving similar treatments were put on a diet containing 1% mace during the periinitiational phase of tumorigenesis, the skin papilloma incidence was reduced to 50% and the average tumor per tumor-bearing mouse was only 1.75. This decline in papilloma was significant (P less than 0.05).

Pregnant SHR mice were treated once with 7,12-dimethylbenz[ a ]anthracene (DMBA) on days 17 – 19 of gestation. F1 and F2 descendants of these mice received multiple skin applications of 12- O -tetradecanoylphorbol-13-acetate (TPA) twice a week for 24 weeks beginning at 12 weeks of age, or applications of solvent alone. The increase in the frequency of skin tumours in F1 and F2 descendants was reported elsewhere. In addition, we report here an increase in overall numbers of tumor-bearing animals, independently of TPA treatment both in F1 and F2 groups compared to respective control groups. Separate statistical analyses were performed for lung tumours, mammary gland tumours, leukaemias and lymphomas. In both generations of descendants of DMBA-treated mothers lung tumour incidence was considerably increased and differed significantly (maximal P -value = 0.003) from control values. Local applications of TPA resulting in strong skin tumour promoting effect described in our previous paper (Napalkov et al., Carcinogenesis, 8(3) (1987) 381) did not produce any significant change in the rates of other types of tumours. The results of the present study provide additional evidence in support of the hypothesis on possibility of hereditary transmission of carcinogenic action of certain chemical compounds.

The present paper reports the chemopreventive action of Dehydroepiandrosterone (DHEA) on Methylcholanthrene- (MCA) induced carcinogenesis in the uterine cervices of adult virgin Swiss albino mice. Placement of sterile double cotton thread impregnated with beeswax containing 600 micrograms of MCA in the cervical canal produced tumors in 85.7% of mice in 16 weeks. When such carcinogen-containing threads were inserted into the uterine cervices of mice that were being fed on diets of 0.025%, 0.05% and 0.1% DHEA for a period of two preinsertion and sixteen postinsertion weeks, the cervical tumor incidences were reduced to 59.0%, 34.7% (P less than 0.01) and 14.2% (P less than 0.01), respectively. It is inferred that DHEA inhibits MCA-induced cervical carcinogenesis and the inhibitory action is dependent upon the dose of the drug.

The incorporation of cis-diammine Dichloro Platinum (II) (cisplatin) on the Ehrlich ascites carcinoma (EAT) cells has been studied in this paper. Ultrastructural study of cells treated 'in vivo' with cisplatin showed that a new treatment with this substance after fixation, blocks uranyl acetate staining with the consequent lack of heterochromatin contrast.

Ceruloplasmin is a copper containing serum glycoprotein. It is an acute-phase protein and its levels are increased in inflammation and in a number of experimental and human tumors. It is normally synthesized in the liver and not in fibroblasts. In this paper we present evidence that ceruloplasmin mRNA is synthesized in Balb/C 3T3 cells and its levels are increased about 3-fold in Rous-Sarcoma virus (RSV) transformed cells. The ceruloplasmin mRNAs from rat liver and RSV 3T3 cells have the same electrophoretic mobility.

The antiproliferative metal chelate bis(2,3,4-trihydroxybenzaldoxyimato)copper(II) (CuTRI2) was shown to distinctly enhance the cytotoxicity of the spleen effector cells of CBA/CA mice to YAC-1 tumor cells in vitro as measured using a 4-h 51Cr release test. The compound was either added directly to the assay system or the effectors were incubated in the presence of it for 2 h and washed before assay. The concentrations tested were 10, 20 and 40 mg/ml, the lowest concentration leading invariably to the strongest enhancement of cytotoxicity. The effector cells involved were very probably natural killer cells. The highest concentration had, if anything, a negative effect on the release of 51Cr from the target cells. In the same concentrations, CuTRI2 did not enhance the cytotoxicity of the spleen effector cells to K-562 tumor cells. Preliminary studies on the related chelate trans-bis(2,4-dihydroxybenzaldoximato)copper(II) are also reported. This paper is apparently the first report of a copper chelate that enhances the cytotoxicity of any sort of effector cells to tumor cells.

The present paper reports the chemopreventive action of indomethacin on methylcholanthrene (MCA)-induced carcinogenesis in the uterine cervix of virgin young adult Swiss albino mice. Placement of a sterile cotton thread impregnated with beeswax containing approx. 600 micrograms of MCA produces cervical tumors in 91% mice in 16 weeks. When such carcinogen-containing threads are inserted into the uterine cervix of mice fed diets containing indomethacin at the dose levels of 10 mg/kg, 20 mg/kg and 40 mg/kg diet for two pre-insertion weeks plus 16 post-insertion weeks, the cervical tumor incidences were 83%, 65% and 26% (P less than 0.01), respectively. It is concluded that indomethacin, when given in the diet at sufficiently high concentration, significantly inhibits MCA-induced cervical carcinogenesis.

In a previous paper we reported that medroxyprogesterone acetate (MPA) decreased the incidence of foreign body tumorigenesis in BALB c mice but that mammary adenocarcinomas appeared in some of the females. The experiment was repeated in 245 virgin females as follows: (1) 40 mice treated with 40 mg of MPA depot s.c. every 2 months during a whole year; (2) 117 mice bearing a foreign body (FB) and treated with MPA; (3) 46 mice bearing a FB; (4) 42 non-treated mice. Mammary adenocarcinomas developed in 16 40 in group 1 and 30 117 in group 2; no mammary tumors appeared in either control groups. The tumors were infiltrating adenocarcinomas often affecting more than one mammary gland; metastases were occasionally observed. Animals killed after 1 year of MPA treatment presented deciduomas. MPA also decreased the incidence of FB-induced sarcomas, confirming previous results.

This paper presents the results of an experiment on the combined action of nitrosodimethylamine and ethyl alcohol in C57BL mice. As shown, alcohol can act to change the target organ of that liver carcinogen by favouring development of olfactory neuroepitheliomas, which infiltrate the frontal lobe of the brain.