bluuebunny/crossref_metadata_2025 huggingface dataset:
Cancer in migrants to uruguay
Authors: De Stefani E. , Parkin D. M. , Khlat M. , Vassallo A. , Abella M.
Published: February 2007

Mortality rates from different cancers in the principal groups of migrants to Uruguay are compared with those in their countries of origin (Argentina, Brazil, Italy and Spain) and in the Uruguay‐born population. Oesophageal cancer is very common in Uruguay and European‐born populations, initially at low risk, appear to acquire rather higher rates after migration. For most migrants, the mortality from cancers of the breast, colon‐rectum, corpus uteri and prostate is closer to the moderately elevated rates of Uruguay than those in their countries of origin. The results suggest that migrants to Uruguay undergo changes in some important environmental exposures, probably dietary, which give rise to substantial alterations in cancer risk within their lifespan.
Enhanced invasiveness and metastatic potential of epithelial cell lines cultured in the presence of dimethyl sulphoxide
Authors: Bentel Jacqueline M. , Rhodes Gregory C. , Markus Irit , Smith Garry J.
Published: February 2007

Several passage cycles of poorly metastatic malignant epithelial cells through immunosuppressed mice failed to induce enhanced metastasis‐forming ability of cells derived from either the primary subcutaneous tumours or the resultant lung metastases. In vitro treatment of cultured malignant cells with dimethyl sulphoxide (DMSO) induced a reversible change in phenotype towards increased invasiveness but did not significantly increase metastasis formation. A cloned‐cell line from a spontaneous in vitro transformant in the presence of DMSO was highly invasive and highly metastatic. In vitro treatment of cultured cells with 2% (v/v) DMSO produced alterations in morphology with decreased growth rate of all cell lines and decreased anchorage‐independent colony formation in several malignant cell lines. All in vitro and in vivo effects were reversible following both short‐ and long‐term (1 year) culture of cells in the presence of DMSO, suggesting epigenetic effects. These data support the concept of independent genetic controls for the invasiveness of tumours and the ability to form metastases.
Immunolocalization of phosphoprotein B23 in proliferating and non‐proliferating hela cells
Authors: Yung Benjamin Y‐M. , Bor Amy M‐s. , Yang Y. H.
Published: February 2007

Localization of protein B23 in HeLa cells under different growth conditions was studied using indirect immunofluorescence. Bright nucleolar fluorescence was observed in exponentially growing cells. After 3 to 4 days, the initial cell inocula entered a phase of stationary growth as defined by no increments in cell number. The nucleolar fluorescence was then diminished and a general nuclear immunofluorexence was observed. This change in localization of fluorescence indicated that protein B23 had migrated out of the nucleoli during the suboptimal growth conditions. Relocation of protein B23 in nucleoli was observed in cells of stationary growth after treatment with adriamycin or daunomycin at their subtoxic concentrations (10−10 M). Adriamycin and daunomycin, at their toxic concentrations (>5.0. ± 10−7 M), on the other hand, inhibited cell growth and induced B23 translocation from nucleoli to nucleoplasm in growing cells. These results indicate that both adriamycin and daunomycin exhibit biphasic effects on the proliferation of cells by either stimulation or inhibition depending on the drug concentrations and the growth conditions. B23 translocation, as observed by immunofluorescence may be a simple and rapid method for assessing inhibition‐stimulation growth response to anti‐tumor therapy.
Heterogeneity of the motility responses in malignant tumor cells: A biological basis for the diversity and homing of metastatic cells
Authors: Kohn Elise C. , Francis Elizabeth A. , Liotta Lance A. , Schiffmann Elliott
Published: February 2007

Tumor metastasis requires highly motile cells that can respond to appropriate stimuli. A2058 human melanoma cells were shown previously to secrete a highly potent autocrine motility factor (AMF) that stimulates chemokinetic movement. We have shown that the insulin polypeptides (IPS; insulin‐like growth factors I and II [IGF‐I, ‐II] and insulin) stimulated A2058 cell chemotaxis and chemokinesis. We now report that the IPs and AMF stimulate locomotion in other human malignant cell lines. Insulin (100 nm) induced motility of up to 50% of the magnitude of the AMF response in human carcinoma lines MDA‐231 (breast), T24 (bladder), and OVCAR3 (ovarian). The tumorigenic and metastatic SR Ha‐ras‐transfected rat embryo fibroblast cell line responded to insulin with both chemotaxis and chemokinesis and was 100% of that seen for AMF. The ED50 for IGF‐I in the carcinoma cell lines was in the order of I nm, but the magnitude of the responses at this concentration was 40% of the AMF‐stimulated response, with the exception of the A2058 cells, which were maximally stimulated at I nn. IGF‐II induced maximal motility of 75 to 130% of the AMF‐stimulated response in the carcinoma lines with ED50, of <10 nM. IGF‐II‐stimulated motility in the carcinoma lines was predominantly chemotactic by modified checkerboard analysis. Cell pretreatment with pertussis toxin inhibited 90‐100% of AMF‐induced motility, whereas migration to the IPS was not pertussis toxinsusceptible. In growth studies, IGF‐I induced mitogenesis up to 140% of basal media control growth. In general, maximal growth stimulation was seen at 100 nn IGF‐I, and optimal migration was seen at 10 nM IGF‐I. The IGFs are secreted by normal stroma in a number of organs that are common sites for primary and metastatic disease. Therefore, we suggest that IPS may be important homing and mitogenic signals for tumor cells in the process of invasion and metastasis and that the differential motility stimulation and respective mechanisms of action by these physiologically important agents may underlie the diversity of the metastatic process.
Tumour‐induced host stromal‐cell transformation: Induction of mouse spindle‐cell fibrosarcoma not mediated by gene transfer
Authors: Russell Pamela J. , Brown Joanne , Grimmond Sean , Stapleton Paula , Russell Peter , Raghavan Derek , Symonds Geoff
Published: February 2007

Tumour‐induced host‐cell transformation has been addressed by examining human tumours in situ and following xenograft to nude mice. We have found evidence for the transformation of host stromal fibroblasts both in vivo and following the introduction of the tumours to in vitro culture. The in vitro culture of one such xenograft‐derived from a human prostatic adenocarcinoma‐resulted in the outgrowth of a transformed aneuploid mouse cell line. This transformed line was tumourigenic both in BALB/c nu/nu (nude) mice and in heterozygous nu/+ mice, with the morphology of a spindlecell sarcoma. The cell line did not express human isozymes or human histocompatibility antigens, nor were human chromosomes present. Moreover, human DNA sequences were notdetected by human Alu repeat sequence element probing in the transformed cell line grown either in vitro or in vivo. The line contained retroviral long terminal repeat sequences but there was no evidence of proviral activation. These findings indicate that tumour cells may cause transformation of neighbouring stromal cells; that this transformation may proceed in the absence of DNA transfer or activation of endogenous proviruses; and that the means of this observed transformation may involve humoral factors elaborated by the tumour cells.
Effects of tumor necrosis factor, alone or in combination with topoisomerase‐ii‐targeted drugs, on human lung cancer cell lines
Authors: Giaccone Giuseppe , Kadoyama Chikabumi , Maneckjee Rhoda , Venzon David , Alexander Richard B. , Gazdar Adi F.
Published: February 2007

Tumor necrosis factor α (TNF) exhibits cytotoxic activity on some solid tumors and has been reported to be synergistic with topoisomerase‐II‐targeted antineoplastic agents. A wide range of TNF concentrations (from 10 to 10,000 U/ml) was tested in 9 human lung cancer cell lines (5 small‐cell and 4 non‐small‐cell carcinomas) using a semi‐automated MTT assay. TNF was not cytotoxic in 8 cell lines, while an adenocarcinoma cell line was marginally sensitive to the cytokine. Using 125I‐TNF we were able to show the presence of specific binding sites for TNF in 4/9 human lung cancer cell lines. Scatchard analysis of the marginally sensitive cell line showed high‐affinity, saturable binding. With 5 cell lines we also tested whether TNF affected the cytotoxicity of doxorubicin and etoposide, 2 topoisomerase II‐targeted drugs which are widely used in the therapy of lung cancer. No significant increase in cytotoxicity was seen when TNF was added to the 2 anti‐neoplastic agents. In contrast to certain other human and mouse lines, human lung cancer cell lines appear to be resistant to TNF, despite the presence of the receptor in some of them; moreover, no synergistic effect of TNF and 2 topoisomerase‐II‐targeted drugs was evident in these human cell lines.
Differential sensitivity of multi‐drug‐resistant and ‐sensitive cells to resistance‐modifying agents and the relation with reversal of anthracycline resistance
Authors: Schuurhuis Gerrit J. , Pinedo Herbert M. , Broxterman Henricus J. , Van Kalken Coenraad K. , Kuiper Catharina M. , Lankelma Jan
Published: February 2007

Calcium channel blockers, calmodulin inhibitors, and some other classes of non‐related compounds reverse multi‐drug resistance. In the present study, we found that several resistance modifiers are more toxic for MDR cells than for the corresponding sensitive parent cells, whereas others show the opposite effect. Several calcium channel blockers including bepridil, diltiazem, nifedipine and verapamil, as well as the calmodulin inhibitor trifluoperazine, were more toxic for several MDR cell lines than for the parent cell lines. In contrast, cross‐resistance for cyclosporin A and the verapamil analogue Ro II‐2933/001 was observed in the MDR/sensitive cell couple CHRC5/AUXB1 probably due to a concentration‐dependent stimulation of cell growth in the range of 0–4 μM cyclosporin A and of 1‐4 μ Ro II‐2933/001. In partially revertant CHRC5 cells, growth inhibition by Ro II‐2933/001 at concentrations below I μ, as seen in CHRC5, cells, changed into growth stimulation, and the collateral sensitivity to verapamil and bepridil disappeared almost completely. In the MDR cells CHRC5 2780AD and DC3F/DMXX, cross‐resistance to another calcium channel blocking agent, Ro II‐1781/001 (tiapamil), was observed as well. This compound showed exceptional behavior: it induced marked potentiation of Dx cytotoxicity as well as stimulation of Dx accumulation in AUXB1 cells, even at low tiapamil concentrations, but not in the CHRC5, cells, even at high concentrations. It is concluded that resistance modifiers can selectively influence growth of MDR cells via more than one process, and resulting in either strong growth inhibition in MDR cells relative to the effect on sensitive cells or in growth stimulation.
Risk factors for hepatocellular carcinoma in catalonia, spain
Authors: Mayans M Vall , Calvet X. , Bruix J. , Bruguera M. , Costa J. , Estève J. , Bosch F. X. , Bru C. , Rodés J.
Published: February 2007

The influence of hepatitis B virus infection, alcohol consumption, tobacco smoking and use of oral contraceptives on the risk of hepatocellular carcinoma (HCC) was evaluated in a hospital‐based case‐control study in Catalonia, in the Mediterranean coastal area of north‐eastern Spain. A total of 96 HCC cases (86.5% of them with associated liver cirrhosis) and 190 age‐ and sex‐matched controls were studied. The odds ratio of HCC and 95% confidence interval among hepatitis B surface antigen (HBsAg) carriers was 4.9 (1.3‐21.9). The OR was not significantly elevated in smokers, and a marginally significant increased risk was found among users of oral contraceptives based on 6 female cases. There was a significant dose‐response relationship between alcohol consumption and risk of HCC (X2 for trend: 24.3, p < 0.001). Although hepatitis B infection was strongly associated with HCC, alcohol abuse leading to cirrhosis appears to be one of the main causes of HCC in this region.
Co‐expression of the genes encoding transforming growth factor‐α and its receptor in papillary carcinomas of the thyroid
Authors: Aasland R. , Akslen L. A. , Varhaug J. E. , Lillehaug J. R.
Published: February 2007

Transforming growth factor‐α (TGF‐α) is frequently co expressed with its receptor, epidermal growth factor receptor (EGF‐R), in several types of carcinoma and sarcoma. It is believed that this results in an autocrine stimulation of tumor growth in these tumors. We have found that TGF‐α and EGF‐R/c‐erbB RNAs were co‐expressed at significantly higher levels in papillary thyroid carcinomas and their lymph‐node metastases than in non‐neoplastic thyroid tissues. We also observed a low level of expression of RNA specific for insulin‐like growth factor I in these tumors, which was highest in a lymphnode metastasis. Autocrine stimulation by TGF‐α may thus be a common feature of papillary carcinomas of the thyroid. Since EGF is known to induce proliferation and dedifferentiation of normal thyroid cells in culture, TGF‐α and its receptor may play an important role in thyroid carcinogenesis.
The role of alcohol in oral and pharyngeal cancer in non‐smokers, and of tobacco in non‐drinkers
Authors: Talamini R. , Franceschi S. , Barra S. , La Vecchia C.
Published: February 2007

Data from a hospital‐based case‐control study of oral and pharyngeal cancer conducted in Northern Italy were used to analyse the risk associated with alcohol in non‐smokers and with tobacco in non‐drinkers. Out of a total of 336 cases (291 males and 45 females) and 1,652 controls (1,272 males and 380 females) 27 cases and 572 controls described themselves as lifelong non‐smokers. Odds ratios (ORs) were 1.5 for 14‐55 vs. 0‐13 alcoholic drinks per week and 2.2 for 56 or over; the trend in risk was statistically significant. Among 19 cases and 213 controls who described themselves as non‐drinkers, the ORs were 3.8 and 12.9 for smokers of < 15 and ≥ 15 cigarettes per day, with a highly significant trend. This study therefore confirms that tobacco has an independent role in the aetiology of oral and pharyngeal cancer, and suggests that alcohol may have an independent role as well, even where, as in Northern Italy, wine is its predominant source. Indeed, ORs were similar to those for tobacco and alcohol individually, each adjusted for the other factor, in the overall data‐set.
Lymphokine‐activated killer (lak) cells discriminate between epstein‐barr virus (ebv)‐positive burkitt's lymphoma cells
Authors: Misko Ihor S. , Schmidt Christopher , Martin Nicole , Moss Denis J. , Sculley Thomas B. , Burrows Scott , Burman Kelcey J.
Published: February 2007

We have generated in vitro lymphokine‐activated killer (LAK) cells from healthy donors by stimulating their mononuclear leukocytes with recombinant interleukin‐2 (rIL‐2) (100 U/ml). After 6 days in culture, the lytic properties of the LAK cells were analyzed in the 51Cr‐release assay by utilizing a target panel of 6 paired lines consisting of an Epstein‐Barr virus (EBV)‐positive Burkitt's lymphoma (BL) cell line and an EBV‐transformed lymphoblastoid cell line (LCL) from the same donor, the Raji BL line and the natural killer (NK) cell‐sensitive K562 line. The patterns of lysis showed that the LAK cells discriminated between two categories of BL cell lines. Group l/ll BL tumor cells which expressed the common acute lymphoblastic leukemia antigen (CALLA), the BL‐associated glycolipid antigen (BLA) and phenotypically resembled biopsy cells were strongly lysed whereas group III BL cells which had assumed an LCL‐like phenotype during culture and lacked the CALLA and BLA surface markers were only poorly lysed. The LCL targets were generally resistant to lysis but the K562 cell line was particularly sensitive. The outcome of cell depletion and monoclonal antibody (MAb) studies indicated that the LAK cell populations were phenotypically and functionally heterogeneous and consisted of at least 2 subpopulations of effector cells; a tumor‐specific component and an NK‐cell‐mediated component.
Abnormal expression and structural modification of the insulin‐like growth‐factor‐ii gene in human colorectal tumors
Authors: Lambert Sylvie , Vivario Jeanine , Boniver Jacques , Gol‐Winkler Rosita
Published: February 2007

The insulin‐like growth factor II (IGF‐II) is a small protein implicated in fetal growth and development. It may play a role in the neoplastic process. The IGF‐II gene is located on the short arm of chromosome 11 near insulin and c‐Ha‐ras I genes. Three distinct promoters control the transcription of this gene, leading to different IGF‐II mRNA species. We have analyzed 21 human colorectal tumors and found overexpression of IGF‐II in 6 of them (30%). When compared with expression in normal adjacent tissues, IGF‐II mRNA increase in these tumors was either moderate (2‐ to 15‐fold) or very marked (200‐ to 800‐fold). In situ hybridization experiments confirmed that high IGF‐II mRNA amounts were localized in cancer cells of the tumors overexpressing the IGF‐II gene. In addition, DNA analysis revealed a structural modification of one IGF‐II locus in one tumor characterized by very high IGF‐II mRNA.
K‐ras mutations (codon 12) are not involved in down‐regulation of mhc class‐i genes in colon carcinomas
Authors: Oliva Maria Rosario , Cabrera Teresa , Esquivias Javier , Perez‐Ayala Millán , Redondo Maximino , Ruiz‐Cabello Francisco , Garrido Federico
Published: February 2007

Fifty‐eight colorectal carcinomas were studied for HLA class‐l antigen expression and for the presence of point mutations in codons 12 and 61 of the K‐ras gene. Eight carcinomas were completely negative for class I by the APAAP technique. Analyses using the polymerase chain reaction (PCR) method, together with selective hybridization using mutation‐specific synthetic oligonucleotides, demonstrated K‐ras mutations in 14 cases (24.1 %), all of them in codon 12. None of the mutations corresponded to the negative cases for class‐l HLA antigen expression. We did not observe any correlation between K‐ras mutations and the extent of tumor differentiation.
Food temperature and gastric cancer
Authors: La Vecchia Carlo , Negri Eva , D′Avanzo Barbara , Franceschi Silvia
Published: February 2007

The relationship between preference for food temperature and the risk of stomach cancer was analysed using data from a case‐control study conducted in Northern Italy on 563 histologically confirmed incident gastric cancers and 1,501 controls admitted to hospital for acute, non‐neoplastic, non‐digestive tract disorders. A specific question was related to food temperature, subjectively defined as “warm”, “hot” or “very hot”. Compared with subjects indicating preference for “warm” foods, the relative risk (RR) was 1.1 (95% confidence interval, C1, 0.9‐1.4) for “hot” and 1.8 (95% C1 = 1.3‐2.4) for “very hot”. The test for trend in risk was statistically significant, and the results were not appreciably modified by allowance for a number of identified potential distorting factors. The elevated risk, however, appeared to be restricted to the 17% of cases reporting a preference for “very hot” foods. This may be due to an absence of substantial mixlassification between “warm” and “very hot”, but also to the existence of a threshold temperature, below which no appreciable thermal irritation is evident. Thus, although the difficulties and uncertainties on measures of food temperature are substantial, these data suggest that thermal irritation may have a role in gastric carcinogenesis.
Histocompatible miniature boar model: Selection of transformed cell lines of b and t lineages producing retrovirus
Authors: Kaeffer Bertrand , Bottreau Elisabeth , Thanh Luu Phan , Olivier Michel , Salmon Henri
Published: February 2007

A lymphoblastoid cell line (BI) was isolated in culture following a brief exposure to 5‐azacytidine from peripheralblood mononuclear cells of a boar previously injected with cells (Shimozuma) producing porcine retrovirus (Tsukuba‐I) and suffering a severe non‐neoplastic syndrome at autopsy. BI cell line and 5 of its sublines were propagated for more than 100 generations, retaining doubling times comprised between 16.8 and 27.5 hr and growing readily in agarose or agar (plating efficiency: 5 to 50%). Karyotype analyses showed that 4 sublines were nearly diploid, except for cells of L14, which displayed a monosomy affecting chromosome 18 pair. Two sublines (L35 and L45) were considered as being of T‐cell lineage, since MSA antigen was observed on the surface of approximately 30% of cells. Three sublines (L23, L14 and L52) were considered of B‐cell lineage, since membrane immunoglobulins were observed on the cell surface. In addition, sublines L23 and L52 were actively secreting immunoglobulin of μ isotype. Retrovirus particles were evidenced in gradient purified preparation of 200‐fold‐concentrated cell culture supernatants of the BI cell line, L14, L35 and L52 sublines, using both a reverse transcriptase activity assay and electron microscopic observation. These cell lines can be used to select for porcine retrovirus variants with transforming potential for lymphocytes of B and T lineages.
Effect of tetragastrin on azaserine‐induced carcinogenesis in rat pancreas
Authors: Tatsuta Masaharu , Iishi Hiroyasu , Baba Miyako , Nakaizumi Akihiko
Published: February 2007

The effect of tetragastrin on pancreatic tumors induced by azaserine was investigated in Wistar rats. Rats were given 25 weekly injections of 10 mg/kg body weight of azaserine and I mg/kg body weight of tetragastrin as a suspension in olive oil every other day. Carcinogen‐induced pancreatic lesions were examined by histochemical techniques, and were classified as ATPase‐positive or ATPase‐negative. In week 62, quantitative histological analysis showed that prolonged administration of tetragastrin had little or no influence on the number and size of the carcinogen‐induced pancreatic lesions, although it caused significantly increased cell proliferation, indicated by a greater labelling index of the pancreatic acinar cells.
Enhancement of anchorage‐independent growth of a human adrenal carcinoma cell line by endogenously produced basic fibroblast growth factor
Authors: Corin Shari J. , Chen Lucian C. , Hamburger Anne W.
Published: February 2007

We have previously observed that a human adrenal carcinoma cell line (SW‐13) produces autocrine growth factors that enhance the ability of these cells to clone in soft agar. We now show that a basic FGF‐like protein is found in SW‐13 lysates and stimulates SW‐13 colony growth. Basic FGF (bFGF) was identified in SW‐13 lysates by both its chromato graphic behavior on heparin‐Sepharose and its reactivity with an antibody specific for bFGF. Incubation of lysates with an tibodies specific for bFGF abolished their ability to support anchorage‐independent growth. Northern analysis demon strated that the cells produced multiple bFGF mRNA tran scripts. SW‐13 cells also expressed bFGF cell‐surface recep tors. These data suggest that SW‐13 cells produce and re spond to a factor structurally and functionally related to bFGF. Such findings support recent evidence indicating that FGF secreted by human tumor cell lines plays a role in the maintenance of the transformed phenotype.
Modulation of the antigenic phenotype of early‐passage human melanoma cells derived from multiple autologous metastases by recombinant human leukocyte, fibroblast and immune interferon
Authors: Giacomini Patrizio , Fraioli Rocco , Nistico Paola , Tecce Raffaele , Nicotra Maria Rita , Filippo Franco Di , Fisher Paul B. , Natali Pier Giorgio
Published: February 2007

We have investigated the relationship between in vitro cultivation of autologous melanoma metastases derived from different patients and their levels of expression of class‐l and‐11 major histocompatibility complex (MHC) antigens and melanoma‐associated antigens (MAAS). Cell cultures were established from 23 individual metastatic melanoma lesions from 10 patients and were tested early after isolation (between 3rd and 10th passages) for both constitutive expression and modulation by recombinant human leukocyte (IFN‐α), fibroblast (IFN‐β) or immune (IFN‐γ) interferon of MHC antigens and MAA. All of the melanoma cell lines displayed altered antigen expression following IFN treatment. While in vitro cultures derived from different individuals varied in both constitutive and IFN‐modified antigenic expression. cultures of autologous metatases derived from the same patient were very similar. In addition, differences in antigenic profile were apparent when early‐passage in vitro cultures were compared with the same melanoma lesion, not established in culture, from which they were derived. The unique de novo and IFN‐modified antigenic phenotype of cultures derived from different patients indicates that the antigenic phenotype displayed by melanoma cultures grown in vitro is genetically determined. The differences found between in vitro cultures and their corresponding in vivo lesions, as well as the antigenic heterogeneity displayed by multiple autologous melanoma lesions in vivo, suggest that the in vivo antigenic phenotype may be determined, at least in part, at an epigenetic level.
A two‐site enzyme‐linked immunosorbent assay for cytokeratin 8
Authors: Sundström B. , Stigbrand T.
Published: February 2007

A monoclonal enzyme‐linked immunosorbent assay (ELISA) was developed for the determination in biological fluids of cytokeratin 8, a potential marker for malignant diseases. Two monoclonal antibodies (MAbs), TS 3 and TS 4, with different epitope specificity, were selected from 4 cytokeratin‐8 reactive antibodies. TS 3 was used for coating and TS 4 as HRP‐conjugate, respectively. Antibodies were selected with the aim of optimizing the discriminatory capacity between cytokeratin 8 levels in sera from healthy persons and from patients with malignant diseases. In sera from healthy individuals the mean value was determined to be 3.1 ± 2.3 ng/ml with an upper cut‐off level of 7.8 ng/ml (+ 2 SD) using purified cytokeratin 8 as standard. Sera from patients with colon cancer and pancreatic cancer were found to have significantly elevated levels, showing a 4‐ to more than 10‐fold increase compared with the normal level. In patients with ovarian cancer no significant elevation was seen. Cytokeratin 8 monitoring may be of value for patients with colon and pancreatic cancer.
Histologic variation among experimental tumors of common origin: Relationships to viral p21 expression and to tumor‐derived extracellular matrix
Authors: Auersperg Nelly , Wong Andre , Maclaren Ian A.
Published: February 2007

Transformed lines, obtained by infection of adult rat adrenocortical fibroblast‐like cells with Kirsten murine sarcoma virus, produce s. c. tumors which range histologically from fibrosarcomas to carcinomas to undifferentiated neoplasms. This study was undertaken to determine whether the histology was a stable characteristic of individual lines and whether it was related to oncogene expression and to differentiation in culture. Three lines were infected at passage 1 and tumor histology, differentiation markers and expression of the transforming protein v‐p21 were evaluated periodically over a 1‐year period. The original stromal characteristics of the target cells (metachromatic extracellular matrix (ECM), a high rate of collagen production and collagen incorporation into ECM, and a fibroblastic morphology) diminished with transformation. In contrast, parenchymal differentiation markers (lipid, steroidogenic enzymes) were enhanced and constitutively expressed in all lines. The two lines in which ECM production was most reduced formed carcinomas in vivo, while the third line showed a smaller shift in these characteristics and formed sarcomas. Thus, histopathology seemed to be influenced by tumor‐derived ECM but unrelated to the expression of steroidogenic properties. The tumors became less differentiated with time, but retained distinct line‐specific phenotypes. Throughout the study, v‐p21 remained overexpressed in all lines to a similar degree, but the subcellular localization of v‐p21 differed between fibroblastic and epithelial cells, suggesting a possible correlation with differentiation.
Quantity and saturation degree of dietary fats as modulators of oxidative stress and chemically‐induced liver tumours in rats
Authors: Hietanen E. , Bartsch H. , Bereziat J.‐C. , Ahotupa M. , Camus A.‐M. , Cabral J. R. P. , Laitinen M.
Published: February 2007

Male rats were fed, from weaning onwards, either 2, 12.5 or 25% sunflower seed oil (polyunsaturated fatty acids, PSA) or lard (saturated fatty acids, SFA) and from the age of 15 weeks subgroups were given N‐nitrosodimethylamine (NDMA) for 30 weeks. Blood levels of lipids were assayed and during the study exhaled ethane was measured as an index of in vivo lipid peroxidation (LPO). At the age of 50 weeks, rats were killed and livers were analysed for tumours. PSA diets decreased plasma cholesterol and triglyceride concentrations vs. respective SFA diet; NDMA administration did not affect plasma cholesterol but enhanced triglyceride concentration. NDMA markedly enhanced LPO. An increase in dietary fat content from 2 to 25% enhanced ethane exhalation, more in rats fed PSA than the SFA diet. In the 25% PSA group, indomethacin in the diet strongly inhibited LPO. Prevalence of liver haemangiosarcomas increased from 42% to 80% (p < 0.05) in NDMA‐treated animals when PSA increased from 2 to 25%; in the group having a 25% PSA diet containing indomethacin, the NDMA‐induced tumour incidence was reduced to 64%. In NDMA‐treated rats fed SFA diets the prevalence of haemangiosarcoma increased from 43% (2% fat) to 67% (25% fat). The data show that NDMA modifies plasma lipids and increases LPO. The quantity and saturation degree of fats altered the frequency of chemically‐induced tumours and modified LPO. As an index of free radical reactions, LPO may have an important role in carcinogenesis. Dietary fat thus appears to promote carcinogenesis through mechanisms that involve LPO.
A comparative study on the effect of tumor promoters on poly ADP‐ribosylation in A431 cells
Authors: Singh Neeta
Published: February 2007

Poly ADP‐ribosylation is a post‐translational modification of chromatin proteins catalyzed by the enzyme poly‐ADPR transferase (poly‐ADPRT) and affects the structure as well as the functional properties of chromatin. It is of particular relevance in carcinogenesis, as it represents an epigenetic mechanism for modulation of gene expression. In the present study, A431 cells were exposed to tumor promoters phorbol 12‐myristate‐ 13‐acetate (PMA), benzoyl peroxide (BP), mezerein and 6‐keto‐lithocholic acid (KA), and their effect on poly‐ADP‐ribosylation was studied. All these tumor promoters increased the activity of poly‐ADPRT in these cells‐PMA 2.3‐fold, BP and mezerein 2.2‐fold each and KA 1.3‐fold. The enzyme inhibitor 3‐amino benzamide (3AB) partially prevented the stimulation of poly‐ADPRT by these promoters. There was a concomitant decrease in NAD levels, the substrate for poly‐ADPRT. The decrease was 44% for PMA, 46% for BP, 21% for KA and 34% for mezerein. The induction of poly‐ADP‐ribose synthesis by PMA and BP appears to be mediated at least in part by active oxygen species, as they induced an increase in superoxide anions and anti‐oxidants prevented the increase of poly‐ADPRT activity to varying extents.
T‐cell subsets, IFN‐γ production and efferent specificity in anti‐parental tumor immunity induced by mouse sensitization with xenogenized variant cells
Authors: Bianchi R. , Fioretti M. C. , Romani L. , Grohmann U. , Cenci E. , Puccetti P.
Published: February 2007

In addition to previous evidence for a role of L3T4+ T cells in the protective anti‐parental tumor immunity induced by xenogenized variant cells of a murine lymphoma (L5I78Y/DTIC), we have investigated the possible participation in this effect of L5I78Y tumor‐specific lymphocytes of the Lyt‐2+ T cell subset. Spleen cells from L5178Y/DTIC tumor‐immunized mice produced high levels of IFN‐γ in vitro in response to parental antigens, and this activity was only abolished by treating the responder population with anti‐Thy‐1.2 antibody or a combination of anti‐L3T4 and anti‐Lyt‐2.2 monoclonal antibodies (MAbs) plus complement. Positively selected L3T4+ and Lyt‐2+ cells also produced IFN‐γ in vitro, provided accessory cells (plastic‐adherent and Thy‐I− Ia− splenocytes, respectively) were added to the lymphocyte‐tumor cell co‐cultures. The production of IFN‐γ by purified L3T4+ and Lyt‐2+ cells was inhibited by addition of the respective anti‐class‐II and anti‐class‐I H‐2 antibody to the cultures. Administration of anti‐IFN‐γ MAb in vivo significantly impaired the resistance of L5178Y/DTIC‐immune mice to challenge with parental cells, as manifested by survival criteria and increased tumor‐cell proliferation in the spleens of antibody‐treated mice. Although anti‐parental tumor protection in vivo and T‐cell activation in vitro for IFN‐γ production were strictly antigen‐specific, bystander tumor inhibition was observed when antigenically irrelevant cells were inoculated with the L5178Y lymphoma. These results suggest that both L3T4+ and Lyt‐2+ T cells play a role in the protective anti‐parental tumor immunity induced by xenogenized cells, and that their activity may involve IFN‐γ‐mediated stimulation of non‐specific tumoricidal mechanisms.
Mechanisms of macrophage‐mediated tumor cell killing: A comparative analysis of the roles of reactive nitrogen intermediates and tumor necrosis factor
Authors: Keller R. , Keist R. , Wechsler A. , Leist T. P. , Van Der Meide P. H.
Published: February 2007

The roles of tumor necrosis factor (TNFα) and reactive nitrogen intermediates (RNI) as effectors of macrophagemediated tumor cell killing were investigated in a variety of tumor cell lines. Three TNFα‐sensitive tumor targets were also susceptible to resting bone‐marrow‐derived mononuclear phagocytes (BMMP). This macrophage lytic activity was markedly diminished or even abolished by anti‐TNFα, indicating that TNFα is the major effector of macrophagemediated killing of these targets. The other 21 tumor cell lines examined were resistant to TNFα but, in their large majority, were more or less susceptible to killing by interferon γ (IFNγ)‐ and Corynebacterium parvum (CP)‐activated BMMP. Among the various analogues of L‐arginine used to assess the role of L‐arginine‐derived RNI as mediators of macrophage tumoricidal activity, NG‐monomethyl‐L‐arginine (NMMA) was most efficient in suppressing RNI secretion by activated macrophages. In some macrophage tumor‐cell combinations, NMMA inhibited both the generation of RNI and the expression of tumoricidal activity in a dose‐dependent manner, suggesting a central role for RNI as effectors. In other combinations, NMMA in concentrations that abolished secretion of RNI either affected tumor‐cell killing only after its induction by IFNγ, or not at all. The findings not only support the thesis that macrophages possess various means of coping with tumor cells but also suggest that the mechanism becoming operative is determined predominantly by the pathway of macrophage activation and the properties of the tumor‐cell type.
Modulation of multidrug resistance by verapamil or mdr1 anti‐sense oligodeoxynucleotide does not change the high susceptibility to lymphokine‐activated killers in mdr‐resistant human carcinoma (LoVo) line
Authors: Rivoltini Licia , Colombo Mario P. , Supino Rosanna , Ballinari Dario , Tsuruo Takashi , Parmiani Giorgio
Published: February 2007

Two sublines were derived from the colon adenocarcinoma line LoVo, the first one was sensitive (LoVo/H) and the second one was made resistant to doxorubicin (LoVo/Dx). When tested for susceptibility to lysis by different types of immune effectors, LoVo/Dx appeared more sensitive than LoVo/H to the killing of CD3+CDS+CD16−, CD3− CD16+‐enriched lymphokine activated killers (LAK) or activated macrophages. In order to check whether this effect was due to different expression of glycoprotein PI70 between the two LoVo sublines (30% vs. 90% of positive cells), a pharmacological and genetic modulation of PI70 was carried out in LoVo cells. Treatment of LoVo/Dx with the calcium channel blocker verpamil (VRP), strongly impaired PI70 function as evaluated by reduced Dx resistance, without affecting the lysability of LoVo/Dx cells by LAKs. Moreover, the significant inhibition of PI70 expression resulting from the treatment of LoVo/Dx with mdrl antisense olideoxynucleotide also failed to change the high lysability of LoVo/Dx by LAKs. These results, therefore, indicate that molecules other than PI70 are involved in the increased lysis of LoVo/Dx subline by immune effectors and that downregulation of the PI70 expression or function will not reduce the potential effectiveness of cancer chemo‐immunotherapy.
MHC class‐I antigen deficiency, malignancy and susceptibility of P815 mastocytoma to NK and macrophage killing
Authors: Bertschmann May , Käsermann Donald , Keller Robert
Published: February 2007

A subline of the murine P815 mastocytoma passaged for a long period of time in histoincompatible hosts was found to be deficient in surface MHC class‐I antigens by serological and biochemical methods. In agreement with the lack of restriction elements, this variant cell line was no longer susceptible to killing by cytotoxic T cells stimulated by and directed against the parental tumor cell line in syngeneic DBA‐2 hosts. We did not observe the appearance of susceptibility to NK killing concomitantly with H‐2 loss. We thus could not confirm the hypothesis of a regulatory function of H‐2 structures in NK recognition/killing. Both cell lines were also resistant to lysis by mouse macrophages. The parental cell line was sensitive to rat macrophage killing, whereas the variant line had lost such sensitivity. In spite of resistance in vitro to various defense mechanisms, the variant H‐2 loss tumor cell line was less tumorigenic in syngeneic hosts and exhibited a lower metastatic capacity than the parental cell line. We propose that in the H‐2 loss subline, survival of cells in vivo is impeded since positive signals mediated by H‐2 structures are missing, which are necessary for cell‐cell contact and survival.
Expression of PDGF β‐receptors in human meningioma cells
Authors: Wang Jia‐Lun , Nistér Monica , Hermansson Monica , Westermark Bengt , Pontén Jan
Published: February 2007

Meningioma is a generally benign tumor derived from arachnoid tissue. We have investigated the presence of functionally active PDGF‐receptors on human meningioma cells in culture. Tumor samples were obtained from 3 surgically removed benign meningiomas and normal arachnoid tissue from an autopsy case. Binding studies were performed by using 125I‐labelled recombinant PDGF‐AA and PDGF‐BB. Only 125I‐PDGF‐BB showed specific binding to all tumor‐cell cultures after incubation of cells for 2 hr at 4°C. Effects of PDGF‐AA and PDGF‐BB on DNA synthesis were measured as 3H‐thymidine incorporation during 48 hr of labelling cells maintained in Eagle's minimum essential medium 0.5% fetal calf serum. PDGF‐BB but not PDGF‐AA stimulated DNA synthesis in all 3 tumor‐cell cultures. Total cellular RNA was analyzed by Northern blotting and hybridization with a 32P‐labelled human PDGF β‐receptor probe, and PDGF β‐receptor mRNA was found in both tumor and arachnoid cell cultures. Furthermore, PDGF β‐receptor mRNA was shown to be present in 2 meningioma biopsies and immunohistochemical staining revealed that PDGF β‐receptors are present in meningioma and arachnoid tissues in vivo. It appears that a possible way of maintaining human meningioma cell growth in vivo is through activation of PDGF β‐receptors.
Dietary factors and breast‐cancer risk in Denmark
Authors: Ewertz Marianne , Gill Caroline
Published: February 2007

The influence of dietary factors, in particular the intake of fat and beta‐carotene, on breast‐cancer risk was evaluated in a case‐control study including 1,486 breast cancer cases diagnosed over a 1 year period in Denmark. The control group was an age‐stratified random sample of 1,336 women from the general population. Data on usual diet prior to the breast cancer diagnosis were collected by self‐administered questionnaires of the semi‐quantitative food frequency type. A highly significant trend (p < 0.001) of increasing risk was observed with increasing fat intake, the RR for the highest quartile being 1.45 (95% Cl 1.17‐1.80) compared with the lowest. However, information was not available to allow adjustment for the possible confounding effect of energy intake. The risk of breast cancer was not associated with consumption of vegetables rich in beta‐carotene, multi‐vitamin tablets or other dietary supplements, coffee, tea, sugar or artificial sweeteners.
Humoral modulation of lymphokine‐activated killer (LAK)‐cell induction in humans: IgG‐related and non‐IgG inhibitors in sera from cancer patients
Authors: Riley Lee B. , Pellis Neal R. , Schantz Stimson P. , Freedman Ralph S. , Balch Charles M. , Itoh Kyogo
Published: February 2007

Soluble inhibitors of lymphokine‐activated killer (LAK) cell induction were characterized and purified from serous fluids from healthy donors or from patients with advanced cancer. Inhibitory activity in sera from cancer patients was partially absorbed with protein A agarose or anti‐human IgG agarose. Following absorption, residual inhibition varied with individ ual sera, suggesting the presence of IgG‐related and non‐IgG inhibitory factors, and the proportions varied in the patient population. IgG, purified by affinity chromatography from ascitic fluids, from plasma of cancer patients, and from plasma of healthy donors, significantly inhibited IL‐2 induction of LAK cells in a dose‐dependent manner. Irrespective of the sources, inhibitory activity resided in the high‐molecular‐weight IgG fraction composed of IgG aggregates and immune complexes, but not monomeric IgG Commercially prepared human IgG in aggregated form, but not in monomeric form, inhibited LAK cell induction in a dose‐dependent manner. In contrast, neither bovine IgG nor human albumin affected LAK cell induction, even at higher concentrations. Aggregated human IgG inhibited LAK cell induction in unfractionated peripheral blood mononuclear cells (PBMC) but not in monocytedepleted peripheral blood lymphocytes (PBL). Despite exten sive (>99%) depletion of IgG by protein‐G affinity chromatography, the serous fluid from cancer patients displayed significant inhibitory activity. Fractionation of the IgG‐depleted inhibitory materials by Sephacryl S‐300, high‐pressure ionexchange column (HPIEC) or gel‐permeation chromatography (HPGPC) demonstrated a 65‐kDa inhibitor, distinct from IgG. Affigel‐blue affinity chromatography of the 65‐kDa fraction depleted albumin but did not remove the inhibitory activity, suggesting that the 65‐kDa inhibitor is not serum albu min nor an albumin‐bound component. These results suggest that serous fluids from patients with advanced‐stage cancer contain 2 distinct regulators for LAK cell induction: (I) aggregated IgG and (2) a 65‐kDa inhibitor, distinct from albumin.
Age at menarche, age at menopause, height and obesity as risk factors for breast cancer: Associations and interactions in an international case‐control study
Authors: Hsieh Chung‐Cheng , Trichopoulos Dimitrios , Katsouyanni Klea , Yuasa Shu
Published: February 2007

The importance of age at menarche, age at menopause, height, and obesity as risk factors for breast cancer, and the possible interactions among these factors in breast cancer causation were investigated in a data set collected in the late 1960's, in an international multicenter case‐control study. Multiple logistic regression procedures were used to model data from 3,993 breast cancer cases and 11,783 controls from 7 study centers representing the range of international variation of breast cancer incidence. Height and obesity (measured through the weight/height2 index) were independent risk factors for breast cancer among post‐menopausal but not pre‐menopausal women; post‐menopausal women taller by 10 cm had a 12% higher risk of breast cancer (95% confidence interval, Cl, 3‐21%) and post‐menopausal women of average height (say 158 cm) had an 11% higher risk of breast cancer (Cl 7‐16%) when they were heavier by 10 kg (and, therefore, more obese by 4 kg/m2). Age at menarche was a risk factor among both pre‐menopausal and post‐menopausal women, a delay of 2 years corresponding to a 10% reduction in breast cancer risk (Cl 6‐15%). Age at menopause was also a breast cancer risk factor, women with menopause at each 5 year age difference having a 17% higher risk of breast cancer (Cl 11‐22%). There is evidence of an interaction (deviation from the logistic regression‐postulated multiplicativity) between obesity and age at menarche, implying that the protective effect of late menarche may not apply to overweight women or that late menarche may become detrimental in obese women. The estimated relative risk coefficients, when applied to average risk factor levels observed among control women, can explain only a small fraction of the difference in breast cancer incidence between Boston and Tokyo.
Expression of HLA‐A, B, C, β2‐microglobulin (β2m), HLA‐DR, ‐DP, ‐DQ and of HLA‐D‐associated invariant chain (Ii) in soft‐tissue tumors
Authors: Mechtersheimer Gunhild , Staudter Martina , Majdic Otto , Dörken Bernd , Moldenhauer Gerhard , Möller Peter
Published: February 2007

Non‐neoplastic mesenchymal cells, along with 33 benign and 87 malignant soft‐tissue tumors (STT) were examined for expression of HLA‐A, B, C, β2‐microglobulin (β2m), HLA‐DR, ‐DP, and ‐DQ molecules and the HLA‐D associated invariant chain (Ii). Serial frozen sections were immunostained using monoclonal antibodies (MAbs) to monomorphic framework determinants of HLA sublocus products, β2m and li, and to CD53, a recently defined broadly distributed pan‐leucocyte molecule. Compared with the normal state, an induction/neo‐expression of HLA‐A, B, C/β2m was found in a considerable number of tumors of muscle, peripheral nerve, cartilageforming, adipose, and vascular tissues. Conversely, some tumors of fibrous origin and of autonomic ganglia showed an abnormal abrogation/loss of HLA‐A, B, C/β2m with respect to their cells of origin. Small, round tumor cells present in various types of STT exhibited a heterogenous pattern of expression of these molecules with a preponderance of HLA‐A, B, C/β2m‐negativity. HLA‐D/Ii determinants were rarely detectable in STT. Besides their expression in some fibrohistiocytic tumors, they were only occasionally found in tumors of smooth‐muscle, peripheral‐nerve and vascular origin as well as in one clear‐cell sarcoma. In all tumors but one, there was no microtopographic association between HLA‐D/Ii‐positive tumor cells and inflammatory cells. CD53 allowed discrimination between dendritic interstitial cells (DIC) and neoplastic cells and additionally revealed that, in contrast to other solid tumors, STT are generally characterized by an extreme scarcity of lymphohistiocytic infiltrates. Our data indicate that, aside from very rare exceptions, aberrant induction or abrogation of MHC molecules in STT occurs in the absence of lymphohistiocytic stromal infiltrates, suggesting that these alterations might not be a consequence of local cytokine effects.