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C Lasserre

Publications and source records attributed to C Lasserre.

At least 19 recordsLinked to original sources
PubMed1999

HIP/PAP gene, encoding a C-type lectin overexpressed in primary liver cancer, is expressed in nervous system as well as in intestine and pancreas of the postimplantation mouse embryo.

We originally isolated the HIP/PAP gene in a differential screen of a human hepatocellular carcinoma cDNA library. This gene is expressed at high levels in 25% of primary liver cancers but not in nontumorous liver. HIP/PAP belongs to the family of C-type lectins and acts as an adhesion molecule for hepatocytes. In normal adult human tissues, HIP/PAP expression is found in pancreas (exocrine and endocrine cells) and small intestine (Paneth and neuroendocrine cells). In order to gain insight into the possible role of HIP/PAP in vivo, we have investigated the pattern of HIP/PAP expression in the developing postimplantation mouse embryo by in situ hybridization. Detailed analysis of developing mouse embryos revealed that HIP/PAP gene exhibits a restricted expression pattern during development. Thus, HIP/PAP transcripts are first observed within the nervous system from day 14.5 onwards in trigeminal ganglia, dorsal root ganglia, and spinal cord where it appears to be an early specific marker of a subpopulation of motor neurons. At laster stages, HIP/PAP transcripts were detected in intestine and pancreas at day 16.5 but not in embryonic liver. This highly restricted expression pattern suggests that HIP/PAP might participate in neuronal as well as intestinal and pancreatic cell development.

Animals↗
PubMed1996

HIP/PAP is an adhesive protein expressed in hepatocarcinoma, normal Paneth, and pancreatic cells.

Human hepatocarcinoma-intestine-pancreas (HIP) cDNA, isolated from a hepatocellular carcinoma, encodes a C-type lectin. According to published cDNA sequences, HIP protein is identical to human pancreatitis-associated protein (PAP). In these sequences, a putative signal peptide and the carbohydrate recognition domain (CRD) can be recognized. In the present study, we established transgenic mice to drive the production of soluble recombinant HIP/PAP protein in the milk of lactating animals; using this model, we showed that HIP/PAP protein was secreted after suitable cleavage of the potential signal peptide. Moreover, we also produced HIP/PAP protein by Escherichia coli cultures performed to generate specific antibodies. These antibodies enabled the detection of HIP/PAP protein in normal intestine and pancreas (both in endocrine and exocrine cells), e.g., intestinal neuroendocrine and Paneth cells, pancreatic islets of Langerhans, and acinar cells. HIP/PAP protein was also identified in the cytoplasm of tumoral hepatocytes but not in nontumoral hepatocytes. Finally, HIP/PAP protein activity was tested and we showed that HIP/PAP induced the adhesion of rat hepatocytes and bound strongly to extracellular matrix proteins (laminin-1, fibronectin), less strongly to type I and IV collagen, and not at all to heparan sulfate proteoglycan. In conclusion, these results showed that HIP/PAP protein was matured on secretion. We also demonstrated that HIP/PAP protein was specifically expressed in hepatocarcinoma cells and interacted with rat hepatocytes and the extracellular matrix. Taken overall, these results suggest that HIP/PAP protein may be of potential importance to liver cell differentiation/proliferation.

Acute-Phase Proteins↗
PubMed1994

Structural organization and chromosomal localization of a human gene (HIP/PAP) encoding a C-type lectin overexpressed in primary liver cancer.

We previously identified, through differential screening of a human primary liver cancer library, a novel gene (named HIP) the expression of which is markedly increased in 25% of human primary liver cancers. HIP mRNA expression is tissue specific since it is restricted to pancreas and small intestine. HIP protein consists in a signal peptide linked to a carbohydrate-recognition domain (CRD), typical of C-type lectins without other binding domains. We have proposed that HIP and related proteins belong to a new family of C-type lectins. Drickamer [Drickamer, K. (1993) Curr. Opin. Struct. Biol. 3,393-400] included this group of proteins in his classification of C-type lectins as the free CRD (group VII) lectins. In the present report we describe the genomic organization and the chromosomal localization of HIP. We have shown that HIP is in fact the pancreatitis-associated protein (PAP) and provided a phylogenetic analysis of the free CRD lectins. Furthermore, the analysis of HIP/PAP gene indicates that the HIP/PAP CRD is encoded by four exons, a pattern shared with all members of this group of proteins. This common intron-exon organization indicates an ancient divergence of the free CRD-lectin group from other groups of C-type lectins. We provide evidence for the localization of HIP/PAP on chromosome 2, suggesting previous duplication of HIP/PAP and the related reg I alpha and reg I beta genes from the same ancestral gene. Finally, the sequence of the 5' upstream region of the HIP gene shows several potential regulatory elements which might account for the enhanced expression of the gene during pancreatic inflammation and liver carcinogenesis.

Amino Acid Sequence↗
PubMed1994

Gene dosage and expression, and enzyme activity of thymidine kinase and thymidylate synthase in xenografted colorectal adenocarcinomas.

Cytogenetic studies performed on human colorectal tumors have revealed 2 specific patterns of chromosomal anomalies. The major pattern, known as the monosomic type (MT), is characterized by the loss or deletion of chromosomes 18, 17 (short arm 17p) and, less frequently, 1p, 4, 15, 5 (long arm 5q) and 21. The other one, known as the trisomic type (TT), is characterized by the gain of several chromosomes: 7, 12, X, 5 and 8. Losses of chromosome 18 and of the 17p arm never coexist in TT tumors. It was observed that many chromosome losses or deletions involved genes encoding for enzymes of the de novo pathways of nucleotide synthesis. In contrast, gains involved genes encoding for enzymes of the salvage pathways of the same metabolism. This led to the hypothesis that chromosome imbalances corresponded to those of nucleotide synthesis in tumor cells. Such an interrelation was confirmed by the dosage of thymidylate synthase (TS) and thymidine kinase (TK) activities in a series of colorectal grafted tumors. This study has been expanded to a larger series of xenografted tumors (23 cases) in which both TS and TK activities were studied, in parallel with an analysis of mRNA, by Northern blotting. The amount of mRNA was found to correlate with the number of gene copies calculated from cytogenetic data, indicating a direct gene-dosage effect. It also correlated with enzyme activities, but less strongly. This suggests the existence of an efficient post-transcriptional regulation, in particular for TS, whose level of expression varies over a wide range. Such variations may explain the diversity of responses to chemotherapy.

Adenocarcinoma↗
PubMed1994

The human HIP gene, overexpressed in primary liver cancer encodes for a C-type carbohydrate binding protein with lactose binding activity.

HIP was originally identified as a gene expression in primary liver cancers, and in normal tissues such as pancreas and small intestine. Based on gene data base homologies, the HIP protein should consist of a signal peptide linked to a single carbohydrate recognition domain. To test this hypothesis HIP and the putative carbohydrate recognition domain encoded by the last 138 C-terminal amino acids, were expressed as glutathione-S-transferase proteins (GST-HIP and GST-HIP-142, respectively). Both recombinant proteins were purified by a single affinity purification step from bacterial lysates and their ability to bind saccharides coupled to trisacryl GF 2000M were tested. Our results show that HIP and HIP-142 proteins bind to lactose, moreover the binding requires divalent cations. Thus the HIP protein is a lactose-binding lectin with the characteristics of a C-type carbohydrate recognition domain of 138 amino acids in the C-terminal region.

Antigens, Neoplasm↗
PubMed1994

Overexpression of glutamine synthetase in human primary liver cancer.

BACKGROUND/AIMS: We have identified several clones specifically expressed during malignant cell proliferation by screening a complementary DNA library constructed from a human primary liver cancer with subtractive probes. One clone was identified as the glutamine synthetase (GS) transcript. Its expression is tightly regulated during development, especially in the hepatic lobule. Because this enzyme is involved in nitrogen homeostasis, it might contribute to tumor development/progression in primary liver cancer. METHODS: We compared the expression of GS messenger RNA (mRNA) and protein in tumorous and nontumorous liver from 34 patients with primary liver cancers, using a combination of Northern blot, dot blot, western blot, and determination of GS enzyme activity. RESULTS: GS mRNA was higher in tumors versus nontumors in 23 of 34 primary liver cancer samples. GS activity was higher in 6 of 8 selected primary liver cancer samples with high RNA levels. GS protein levels were proportional to enzyme activity. A major GS transcript of 2.8 kilobase was detected by Northern blotting and sequencing. This comprised the minor 1.8-kb transcript and a long 3' untranslated region; the latter contained an AT-rich zone, fully conserved in the chicken, mouse, and rat, which might be important for stability. CONCLUSIONS: Our results show an overexpression of GS in human primary liver cancers and, thus, point to its potential involvement in hepatocyte transformation.

Amino Acid Sequence↗
PubMed1992

A novel gene (HIP) activated in human primary liver cancer.

Differential screening of a human hepatocellular carcinoma complementary DNA library using subtracted probes allowed us to identify a novel gene named HIP whose expression at the transcriptional level was elevated in liver tumors. The protein potentially encoded by the complementary DNA showed 68.5% identity with the bovine pancreatic thread protein and 49% identity with the human reg protein, which has been proposed as a pancreatic islet cell regenerating factor and is identical to the pancreatic stone or pancreatic thread protein. Sequence analysis suggests that the bovine pancreatic thread protein encoding gene is, in fact, the bovine homologue of the HIP gene. Furthermore, data base searches revealed a significant similarity of the HIP and pancreatic stone protein/pancreatic thread protein/reg sequences with the C-type lectin superfamily. The HIP sequence, like pancreatic stone protein/pancreatic thread protein/reg protein, consists of a single carbohydrate recognition domain linked to a signal peptide which would be involved in secretion of the protein. HIP mRNA was expressed at a high level in the tumors of seven of 29 hepatocellular carcinomas. In contrast, HIP mRNA was not detected in nontumorous adjacent areas or in normal adult and fetal liver, suggesting that HIP could be involved in liver cell proliferation or differentiation. HIP mRNA expression is tissue specific, since it is present in the normal small intestine and pancreas, while it could not be evidenced in colon, brain, kidney, or lung. In summary, our results show the existence of a novel family within the superfamily of C-type lectin which may be involved in liver, pancreatic, and intestinal cell proliferation or differentiation.

Amino Acid Sequence↗
PubMed1991

Insulin-like growth factor II (IGF-II) mRNA expression during hepatocarcinogenesis in transgenic mice.

Insulin-like growth factor II (IGF-II) mRNA expression is developmentally regulated in liver tissue. We previously observed the reexpression of fetal IGF-II mRNAs in human primary liver cancer and in surrounding cirrhotic tissue. In order to determine the steps of liver cancer progression where the activation of IGF-II fetal mRNAs occurs, we analyzed IGF-II mRNA expression during hepatocarinogenesis in transgenic mice carrying an antithrombin III-SV40 early region hybrid gene. The comparative analysis of mRNAs encoding IGF-II and other differentiation-associated proteins, as well as histological analysis, indicate that the reexpression of fetal IGF-II mRNAs takes place in specific steps of liver cancer progression, both in early pretumorous lesions and in well-differentiated hepatocellular carcinomas.

Aging↗
PubMed1991

Expression of insulin-like growth factor II, alpha-fetoprotein and hepatitis B virus transcripts in human primary liver cancer.

Insulin-like growth factor II is a fetal growth factor structurally and functionally related to insulin and insulin-like growth factor I. Its mRNA expression is developmentally regulated in human liver, the reexpression of insulin-like growth factor II fetal transcripts being often observed in primary liver cancer. Insulin-like growth factor II and alpha-fetoprotein mRNAs were studied in 16 human primary liver cancers, most of which were highly differentiated. Hepatitis B virus transcripts were also analyzed in the tumors from hepatitis B virus chronic carriers. alpha-Fetoprotein mRNA was detected in only four tumors and in one nontumorous cirrhotic tissue; all these samples also displayed insulin-like growth factor II fetal transcripts. Furthermore, fetal insulin-like growth factor II mRNAs were observed in five tumors and six nontumorous cirrhotic areas not expressing alpha-fetoprotein mRNA. The presence of hepatitis B virus RNA was only observed in tissues not expressing alpha-fetoprotein or fetal insulin-like growth factor II mRNA. In conclusion, fetal insulin-like growth factor II transcripts are more frequently observed than alpha-fetoprotein mRNA in highly differentiated liver cancers and in surrounding cirrhotic areas. The reexpression of fetal insulin-like growth factor II transcripts might then be a marker of early steps of liver cell transformation.

Carrier State↗
PubMed1990

Expression of insulin-like growth factor II (IGF-II) in human primary liver cancer: mRNA and protein analysis.

Insulin-like growth factor II (IGF-II) is a polypeptide growth factor thought to be involved in fetal tissue development. We previously showed an increased expression of IGF-II mRNA in human primary liver cancer. The present investigation was undertaken to characterize the overexpressed IGF-II transcripts and to determine whether they are translated into protein. Two cDNAs with distinct 5' untranslated regions, corresponding to IGF-II transcripts expressed in fetal liver, were isolated from a primary liver cancer. Complete nucleotide sequence analysis showed an identical open reading frame of 540 bp, encoding a predicted polypeptide identical to the IGF-II isolated from serum. An increased synthesis of IGF-II protein was demonstrated by a protein-binding assay in tumorous liver samples, the highest levels being found in primary liver cancers with the highest IGF-II steady state level. By contrast, serum IGF-II content was low in most of primary liver cancer cases analyzed. Altogether, the results indicate reexpression of IGF-II both at the mRNA and protein levels in primary liver cancer. This finding is consistent with IGF-II being a marker of liver cell differentiation. In addition, this growth factor might be involved in liver cancer progression by an autocrine and/or paracrine mechanism.

Adenoma, Bile Duct↗
PubMed1988

Differential expression of insulin-like growth factor II mRNA in human primary liver cancers, benign liver tumors, and liver cirrhosis.

We investigated insulin-like growth factor II (IGF-II) mRNA in three groups of human liver samples including primary liver cancers, benign liver tumors and cirrhosis; indeed these pathological conditions would allow us to distinguish between different steps in liver carcinogenesis. A 40- to 100-fold increase in IGF-II mRNA was shown in 9/40 of the liver cancer samples as compared to normal adult liver. RNA blot analysis using both IGF-II cDNA and oligonucleotide probes showed the reexpression of two fetal (6 and 5 kilobases) IGF-II transcripts in primary liver cancers and in some cirrhotic adjacent tissues; these included all the samples with enhanced IGF-II expression. By contrast the adult (5.3 kilobases) IGF-II transcript was identified in most of the benign liver tumors and liver cirrhosis; in addition, in some of these samples, the 5-kilobase fetal transcript was also detected. The increase of IGF-II mRNA in some liver cancers is consistent with an autocrine mechanism conferring a selective growth advantage to tumorous liver cells. Furthermore, these results indicate a differential expression of IGF-II transcripts in nonmalignant hepatocyte proliferation (benign liver tumors and cirrhosis) as compared to liver cancer. Finally this study suggests that, in liver cirrhosis and in some benign liver tumors, premalignant proliferative states might be identified by the presence of IGF-II fetal transcripts.

Fetus↗
PubMed1985

Differential expression of two linked selection genes (HSVI-tk and Eco.gpt) in transformed teratocarcinoma and in L cells.

Upon transfection of (TK-)F9 teratocarcinoma stem-cells and (TK-)L fibroblasts with a plasmid carrying two selection genes, Eco.gpt and HSVI-tk, selection for gpt gene yielded ten times fewer colonies than selection for tk. Only the transformed clones selected for gpt had measurable xanthine guanine phosphoribosyltransferase (XGPRT) activity (Jami et al., 1983). Eco.gpt coding for XGPRT was under the control of simian virus 40 (SV40) early genes' regulating sequences (SV-gpt). In the present study, it was verified that the low efficiency of gpt selection in mouse cells was not due to the eucaryotic controlling sequences added to the bacterial gene. The transformed clones selected for tk that had no XGPRT activity possessed at least one uninterrupted copy of the composite SV-gpt gene and as many copies of the transforming plasmid as the cells selected for gpt expression. In a further test, the gpt gene was placed under the control of tk-regulating sequences and inserted with the tk gene in the same vector. Under these conditions, expression of XGPRT in the transformed clones selected for tk was improved, even though relative selection for gpt remained low.

Animals↗
PubMed1984

Transformation of teratocarcinoma stem cells and fibroblasts with various vectors containing the Eco.gpt gene as a selection marker.

Eco.gpt, which codes for xanthine guanine phosphoribosyltransferase (XGPRT), when placed under the control of SV40 early genes regulating sequences (pSV2gpt) selects transformed teratocarcinoma cells with a low efficiency. The SV40 promoter may not function efficiently in teratocarcinoma stem cells, as suggested by the fact that such cells do not support SV40 T antigen expression. We have tested whether one could change the efficiency of gpt as a dominant selective marker in transformation by several operations. (1) Deletion of 121 base pairs (bp) upstream the bacterial coding sequence gpt (pQS14) did not make any difference. (2) Replacement of the SV40 regulating sequences by the HSV tk regulating sequences (pQS15) resulted in ten times fewer transformants with PCC4 teratocarcinoma cells as well as with L cells. No XGPRT activity was detectable in cultures 48 h after transfection. (3) Reintroduction of the PvuII-HindIII SV40 fragment (which contains an enhancing sequence together with the origin of replication and the early promoter of the virus) into the pQS15 vector, either in 5' or 3' from tk-gpt composite gene (pQS20 and pQS22) allows selection of ten to twenty times more transfected PCC4 or L cells colonies and restores transient XGPRT activity upon transfection. Whatever the vector used, the transformation frequency of PCC4 teratocarcinoma cells remains ten times lower than that of L cells. It appears that the presence of the SV40 PvuII-HindIII fragment in the vector increases cell transformation even with PCC4 cells and that the low frequency obtained with pSV2pgt is likely not due to the use of the SV40 early promoter.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Persistence of transcription of the human beta-globin gene in hybrids between transfected F9 embryonal carcinoma and L cells.

Extinction of the phenotypic properties of the embryonal carcinoma (EC) cell parent is always observed in hybrids between EC cells and L fibroblasts. On the other hand, human beta-globin genes can be expressed when recombined to EC cell genome. We wanted to examine whether this ectopic expression would be extinguished when phenotypic changes are induced by cell hybridization. F9 transformants carrying the human beta-globin gene were hybridized with L fibroblasts. Human beta-globin transcripts were found in the two hybrid cell lines examined. Thus, the human beta-globin genes escaped extinction and behaved as genes involved in housekeeping functions.

Animals↗
PubMed1983

Stable transformation of mouse teratocarcinoma stem cells with the dominant selective marker Eco.gpt and retention of their developmental potentialities.

Transformation of PCC4 mouse teratocarcinoma stem cells was obtained using a dominant selective marker, the enzyme xanthine-guanine phosphoribosyltransferase (XGPRT), coded by the bacterial Eco.gpt gene placed under the control of the early SV40 genes in the vector pSV2gpt. An average of 20 colonies of transformed cells was obtained, using the calcium phosphate technique, 10 microg DNA vector, no carrier DNA and 1 x 10(6) recipient cells. Five independent Eco.gpt-transformed PCC4 cell lines were propagated in selective medium and assayed for XGPRT activity. All of them had the ability to convert [14C]xanthine to xanthine monophosphate. pSV2gpt sequences were present and associated with high mol. wt. cellular DNA. pSV2gpt sequences and XGPRT activity were both conserved in the three clones that were propagated in non-selective medium for 30 generations. The transformed PCC4 cells retained their ability to produce, in host mice, teratocarcinoma tumors composed of embryonal carcinoma and various differentiated tissues. Thus, pSV2gpt can be used as a dominant marker to select teratocarcinoma stem cells co-transformed with genes that are not selectable by themselves.

Animals↗
PubMed1981

Conservation of the syntenic group enol - pgd - pgm in mammals: its assignment to chromosome 2 in the Chinese hamster.

Hybrids between cells from mouse permanent lines and Chinese hamster thymus cells explanted from animals maintained mouse chromosomes and lost most hamster chromosomes. In twenty-seven hybrids examined for expression of enolase 1. phosphogluconate dehydrogenase, and phosphoglucomutase, the Chinese hamster forms of the three enzymes were either expressed together, or not expressed at all. Thus, the three genes eno1, pgd, and pgm appear syntenic in Chinese hamster as they are in man (chromosome 1p), and in mouse (chromosome 4). The three markers map on the Chinese hamster chromosome 2.

Animals↗
PubMed1980

Patterns of chromosome segregation in Chinese hamster x mouse cell hybrids between permanent cell lines and thymus cells.

Hybrids between a tumorigenic Chinese hamster cell line (DC3F-aza) and normal mouse thymus cells very rapidly lost most of their mouse chromosomes, whereas hybrids between tumorigenic mouse cell lines (either Cl.1D of L cell line origin, or PCC4-aza 1 teratocarcinoma cells) and normal Chinese hamster thymus cells lost most of their hamster chromosomes. From three such fusion experiments, 20 cell lines were developed which all followed the same evolution, namely, the elimination of the majority of the chromosomes contributed by the normal thymus cell. In some hybrids, the elimination process resulted in the total absence of intact chromosomes contributed by the thymus cell parent. Such hybrids were distinguished from revertant parental cells growing in the selective medium by the presence of at least one enzyme in their cell extracts which displayed the electrophoretic mobility of the enzyme of the thymus cell parent. These observations, together with data from other reports, suggest that, as a rule, interspecific cell hybrids which develop upon fusion between normal diploid cells and tumorigenic cell lines maintain the chromosomes of the latter and eliminate preferentially many or most of the chromosomes contributed by the normal cell parents, independent of the respective species of the parental cells.

Animals↗