Can cancer cells transform normal host cells into malignant cells?

A human prostate tumour cell line, LNCaP C4-2, when injected into athymic male nude mice, produced tumours containing: (1) only human cancer cells similar to those injected; (2) only murine stromal cells containing abnormal chromosome constitutions; or (3) both human prostate cancer cells similar to those injected and the transformed murine stromal cells with altered chromosome constitutions. Karyotypic analysis of murine metaphases from all the host-derived tumours showed mostly pseudodiploid chromosome constitutions, with multiple copies (amplification) of mouse chromosome 15 and the absence of a typical Y chromosome. Fluorescence in situ hybridization analysis of these murine cells, using a biotin-labelled total human DNA painting probe, further demonstrated the absence of human DNA and the presence of only mouse metaphase and interphase cells in these transformed stromal cells. These results suggest that cancer cells are capable of inducing neoplastic transformation in stromal cells of the host organ by some, as yet unknown, epigenetic mechanism(s).     

The murine Fhit locus: isolation, characterization, and expression in normal and tumor cells

The murine Fhit locus maps near the centromere nu proximal Ptprg locus on mouse chromosome 14. The cDNA sequence and structure are similar to those of the human gene, with exons 5-9 encoding the protein. The predominant mRNA in the tissues and cell lines tested was an alternatively spliced form missing exon 3. Most murine cell lines tested, including lines established from normal mouse embryos and tumors, expressed very low or undetectable levels of Fhit mRNA. Most normal mouse tissues expressed wild-type Fhit mRNA, whereas approximately 40% of murine lung carcinomas expressed wild-type and aberrant Fhit RT-PCR products that lacked various exons. Several tumorigenic mouse cell lines exhibited homozygous deletions of Fhit exons. We conclude that the murine Fhit gene, like its human counterpart, is a target of alterations involved in murine carcinogenesis.     

Human NKR-P1A. A disulfide-linked homodimer of the C-type lectin superfamily expressed by a subset of NK and T lymphocytes

In rodents, the NKR-P1 family of glycoproteins are preferentially expressed on NK cells and have been implicated in NK cell function. In this study, we describe the characterization and cloning of a human homologue. Human (h)NKR-P1A cDNA was cloned from a NK cell cDNA library by expression in COS7 cells with the use of the DX1 mAb. hNKR-P1A is a type II membrane glycoprotein with characteristic properties of the C-type lectin superfamily. Comparison of the predicted amino acid of human NKR-P1A with rat and mouse NKR-P1 indicates 46% homology. NKR-P1A is on human chromosome 12, the syntenic of mouse chromosome 6, where the murine NKR-P1 genes are located. All rat NK cells express NKR-P1; however, hNKR-P1A is present on only a subset of human NK cells. Although rodent T cells only infrequently express NKR-P1, hNKR-P1A is present on approximately 25% of adult peripheral blood T cells, including both CD4+ and CD8+ T cells, and is expressed preferentially on adult T cells with a "memory" antigenic phenotype. The anti-hNKR-P1A mAb failed to affect lysis of NK-sensitive targets; however, the spontaneous cytotoxicity mediated by certain NK cell clones against the murine P815 cell target was blocked by anti-hNKR-P1A mAb. Our findings demonstrate that NKR-P1A is a human homologue of the rodent NKR-P1 genes and suggest that this molecule may be involved in NK cell function.     

Cloning, expression and chromosomal localization of Wnt-13, a novel member of the Wnt gene family

The Wnt genes, encoding structurally-related secreted glycoproteins, are implicated in mammary carcinogenesis induced by mouse mammary tumor virus. In search of the Wnt gene(s) expressed in human gastric cancer, a WTGC1 cDNA fragment sharing 66.9% amino-acid homology with human and mouse Wnt-2 was isolated by degenerate polymerase chain reaction. The human gene corresponding to WTGC1 was designated as Wnt-13 and overlapping Wnt-13 cDNAs were cloned. Nucleotide sequence analysis indicated that the Wnt-13 gene encodes the protein of 372 amino acids, including a signal peptide, two potential N-glycosylation sites and 24 cystein residues highly conserved among members of the Wnt gene family. The Wnt-13 mRNA of 2.5 kb in size was detected in heart, brain, placenta, lung, prostate, testis, ovary, small intestine and colon of adult human and also in brain, lung and kidney of fetal human. Among various cancer cell lines, the Wnt-13 mRNA was detected in HeLa (cervical cancer), MKN28 and MKN74 (gastric cancer). The Wnt-13 gene has been mapped to human chromosome 1p13. These results suggest that the Wnt-13 gene may be involved in normal human development or differentiation as well as in human carcinogenesis.     

Cyclosporine trough concentrations in predicting allograft rejection and renal toxicity up to 12 months after renal transplantation

We recently identified a novel gene (PB39) (HGMW-approved symbol POV1) whose expression is up-regulated in human prostate cancer using tissue microdissection-based differential display analysis. In the present study we report the full-length sequencing of PB39 cDNA, genomic localization of the PB39 gene, and genomic sequence of the mouse homologue. The full-length human cDNA is 2317 nucleotides in length and contains an open reading frame of 559 amino acids which does not show homology with any reported human genes. The N-terminus contains charged amino acids and a helical loop pattern suggestive of an srp leader sequence for a secreted protein. Fluorescence in situ hybridization using PB39 cDNA as probe mapped the gene to chromosome 11p11.1-p11.2. Comparison of PB39 cDNA sequence with murine sequence available in the public database identified a region of previously sequenced mouse genomic DNA showing 67% amino acid sequence homology with human PB39. Based on alignment and comparison to the human cDNA the mouse genomic sequence suggests there are at least 14 exons in the mouse gene spread over approximately 100 kb of genomic sequence. Further analysis of PB39 expression in human tissues shows the presence of a unique splice variant mRNA that appears to be primarily associated with fetal tissues and tumors. Interestingly, the unique splice variant appears in prostatic intraepithelial neoplasia, a microscopic precursor lesion of prostate cancer. The current data support the hypothesis that PB39 plays a role in the development of human prostate cancer and will be useful in the analysis of the gene product in further human and murine studies.     

Absorbed fraction to the cell nucleus for low energy electrons

The Drosophila dishevelled gene (dsh) encodes a secreted glycoprotein, which regulates cell proliferation, acting as a transducer molecule for developmental processes, including segmentation and neuroblast specification. We have isolated and characterized cDNA clones from two different human dsh-homologous genes, designated as DVL-1 and DVL-3. DVL-1 and DVL-3 putative protein products show 64% amino acid identity. The DVL-1 product is 50% identical to dsh and 92% to a murine dsh homologue (Dvl-1). Both human DVL genes are widely expressed in fetal and adult tissues, including brain, lung, kidney, skeletal muscle and heart. DVL-1 locus maps to chromosome 1p36 and DVL-3 to chromosome 3q27. DVL-1 locus on chromosome 1 corresponds to the murine syntenic region where Dvl-1 is located. DVL-1 and DVL-3 are members of a human dsh-like gene family, which is probably involved in human development. Although the precise role of these genes in embryogenesis is only conjectural at present, the structural and evolutionary characteristics suggest that mutations at their loci may be involved in neural and heart developmental defects.     

Factors associated with marijuana use among American Indian adolescents

The BCMA gene is a new gene discovered by the molecular analysis of a t(4;16) translocation, characteristic of a human T cell lymphoma. It has no significant similarity with any known protein or motif, so that its function was unknown. This report describes the cloning of murine BCMA cDNA and its genomic counterpart. The mouse gene is organized into three exons, like the human gene, and lies in murine chromosome 16, in the 16B3 band, the counterpart of the human chromosome 16p13 band, where the human gene lies. Murine BCMA cDNA encodes a 185 amino acids protein (184 residues for the human), has a potential central transmembrane segment like the human protein and is 62% identical to it. The murine BCMA mRNA is found mainly in lymphoid tissues, as is human BCMA mRNA. Alignment of the murine and human BCMA protein sequences revealed a conserved motif of six cysteines in the N-terminal part, which strongly suggests that the BCMA protein belongs to the tumor necrosis factor receptor (TNFR) superfamily. Human BCMA is the first member of the TNFR family to be implicated in a chromosomal translocation.     

Phenylacetyl-CoA:acceptor oxidoreductase, a new alpha-oxidizing enzyme that produces phenylglyoxylate. Assay, membrane localization, and differential production in Thauera aromatica

Telomerase activity is upregulated in activated and malignant lymphocytes. We studied the correlation of telomerase and IL-10 to leukemia transformation in the NZB mouse model of human chronic lymphocytic leukemia (CLL). Telomerase levels increased from early to late leukemic stages, likewise IL-10 gene expression levels increased with the leukemic progression. The inverse relationship of telomerase and IL-10 levels to the survival of NZB mice was also established. Our data suggested that telomerase and IL-10 were involved in transformation in the murine model of CLL and the detection of telomerase activities might be of value in the prediction of CLL progression.     

A novel gene, AF-1p, fused to HRX in t(1;11)(p32;q23), is not related to AF-4, AF-9 nor ENL

Most of the translocations affecting the chromosome band 11q23, frequently seen in human acute leukemias, involve a restricted area of the HRX gene. We have characterized two t(1;11)(p32;q11) translocations which fuse the HRX gene to a novel gene, AF-1p on chromosome 1p32, in two myeloid leukemias. The der (11) chromosome expresses the 1368 N-terminal amino acids of HRX, including the AT-hook, snRNP and methyltransferase similarities, fused to almost all the AF-1p product. The predicted wild type AF-1p product is a 98 kDa acidic protein which does not exhibit similarity to the AF-4, AF-9 and ENL gene products. It is highly similar to the murine eps 15 gene product, which encodes a cytoplasmic phosphoprotein. Our data indicate that AF-1p defines another class of genes fused to HRX in 11q23 abnormalities.     

A highly conserved major histocompatibility complex class I-related gene in mammals

We report here a cDNA sequence of a murine homolog of the human major histocompatibility complex (MHC) class I-related gene, MR1. The analyses revealed unprecedentedly high conservation of MR1 in the alpha1 and alpha2 domains (corresponding to the peptide-binding domains in the classical MHC class I molecules) between human and mouse (predicted amino acid identity: 90 and 89% for the alpha1 and alpha2 domain, respectively), compared to MHC class I and other class I molecules. On the other hand, conservation in the alpha3 domain (73%) is comparable to those of others, suggesting domain-specific conservation of MR1. The localization of the mouse MR1 gene was determined to be chromosome 1H1, which corresponds to the human chromosomal region where the human MR1 gene is located (chromosome 1q25). High conservation of MR1 among mammals suggests that MR1 may be involved in critical conserved biological function(s).     

Histopathological and morphometric study of the late effects of heavy-ion irradiation on the spinal cord of the rat

Recently, interest has focused on the human gene encoding the putative protein homologous to VAT-1, the major protein of the synaptic vesicles of the electric organ of the Pacific electric ray Torpedo californica, after it has been localized on chromosome locus 17q21 in a region encompassing the breast cancer gene BRCA1. Chromosomal instability in this region is implicated in inherited predisposition for breast and ovarian cancer. Here we describe isolation and biochemical characterization of a mammalian 48 kDa protein homologous to the VAT-1 protein of Torpedo californica. This VAT-1 homolog was isolated from a murine breast cancer cell line (Ehrlich ascites tumor) and identified by sequencing of cleavage peptides. The isolated VAT-1 homolog protein displays an ATPase activity and exists in two isoforms with isoelectric points of 5.7 and 5.8. cDNA was prepared from Ehrlich ascites tumor cells, and the murine VAT-1 homolog sequence was amplified by polymerase chain reaction and partially sequenced. The known part of the murine and the human translated sequences share 97% identity. By Northern blots, the size of the VAT-1 homolog mRNA in both murine and human (T47D) breast cancer cells was determined to be 2.8 kb. Based on the presented data, a modified gene structure of the human VAT-1 homolog with an extended exon 1 is proposed. VAT-1 and the mammalian VAT-1 homolog form a subgroup within the protein superfamily of medium-chain dehydrogenases/reductases.     

Anaerobic regulation of the Escherichia coli dmsABC operon requires the molybdate-responsive regulator ModE

The 9804 gene, which encodes a human Ly-6 protein most similar to mouse differentiation Ag TSA-1/Sca-2, has also been called RIG-E. Like mouse TSA-1, it has a broad tissue distribution with varied expression levels in normal human tissues and tumor cell lines. Like some members of the murine Ly-6 family, the 9804 gene is responsive to IFNs, particularly IFN-alpha. Overlapping genomic fragments spanning the 9804 gene (5543 bp) have been isolated and characterized. The gene organization is analogous to that of known mouse Ly-6 genes. The first exon, 2296 bp upstream from exon II, is entirely untranslated. The three coding exons (II, III, and IV) are separated by short introns of 321 and 131 bp, respectively. Primers were developed for specific amplification of 9804 gene fragments. Screening of human-hamster somatic cell hybrids and yeast artificial chromosomes (YACs) indicated that the gene is distal to c-Myc, located in the q arm of human chromosome 8. No positives were detected from the Centre d'Etude du Polymorphisme Humain mega-YAC A or B panels, nor from bacterial artificial chromosome libraries; two positive cosmids (c101F1 and c157F6) were isolated from a human chromosome 8 cosmid library (LA08NC01). Fluorescence in situ hybridization of metaphase spreads of chromosome 8, containing hybrid cell line 706-B6 clone 17 (CL-17) with cosmid c101F1, placed the 9804 gene close to the telomere at 8q24.3. This mapping is significant, since the region shares a homology with a portion of mouse chromosome 15, which extends into band E where Ly-6 genes reside. Moreover, the gene encoding E48, the homologue of mouse Ly-6 molecule ThB, has also been mapped to 8q24.     

The X-linked immunodeficiency defect in the mouse is corrected by expression of human Bruton's tyrosine kinase from a yeast artificial chromosome transgene

Mutations in the gene for Bruton's tyrosine kinase result in the B cell differentiation defects X-linked agammaglobulinemia in man and X-linked immunodeficiency in mice. Here we describe the generation of two yeast artificial chromosome (YAC)-transgenic mouse strains in which high-level expression of human Btk is provided by endogenous regulatory cis-acting elements that are present on a 340-kb transgene, Yc340-hBtk. The expression pattern of the transgenic human Btk was found to parallel that of the endogenous murine gene. When the Yc340-hBtk-transgenic mice were mated onto a Btk-deficient background, the xid B cell defects were fully corrected: conventional and CD5+ B-1 B cells were present in normal numbers, serum IgM and IgG3 levels as well as responses to T cell-independent type II antigens were in the normal ranges. In vivo competition experiments in Btk+/- female mice demonstrated that in the conventional B cell population the Yc340-hBtk transgene could fully compensate the absence of expression of endogenous murine Btk. We conclude that in the YAC-transgenic mice Btk is appropriately expressed in the context of native regulatory sequences.     

Genetic structure and chromosomal mapping of MyD88

The myeloid differentiation (MyD) marker MyD88 was initially characterized as a primary response gene, upregulated in mouse M1 myeloleukemic cells in response to differentiation induced by interleukin-6. Subsequent analysis revealed that MyD88 possesses a unique modular structure, which consists of an N-terminal "death domain," similar to the intracellular segments of TNF receptor 1 and Fas, and a C-terminal region related to the cytoplasmic domains of the Drosophila morphogen Toll and vertebrate interleukin-1 receptors. In this report we describe the cloning and gene structure of mouse MyD88. The complete coding sequence of mouse MyD88 spans five exons, with the first exon encoding the complete death domain. Zooblot analysis revealed that MyD88 is an evolutionarily conserved gene. MyD88 was localized to the distal region of mouse chromosome 9 by interspecific backcross mapping. The human homolog (hMyD88) was mapped to chromosome 3p22-p21.3 by PCR analysis of a human chromosome 3 somatic cell hybrid mapping panel. Northern blot analysis revealed widespread expression of MyD88 in many adult mouse tissues, and RT-PCR studies detected MyD88 mRNA in T and B cell lines and differentiating embryonic stem cells. The broad expression pattern demonstrates that mouse MyD88 expression is not restricted to cells of myeloid lineage as was originally believed.     

Murine thymic lymphoma is associated with a species-specific hematopoietic progenitor cell subpopulation

Many strains of laboratory mouse are uniquely susceptible to the development of T cell lymphoma/leukemia, either spontaneously or as a result of chemical or radiation exposure. In contrast, T cell leukemias or lymphomas which are relatively uncommon in human populations, are not easily induced by radiation, and are not generally associated with chemotherapy or chemical exposure. Evidence is presented to suggest that differences in the susceptibility to the development of these malignancies is related to subtle but important variations in the regulation of hematopoietic stem cell differentiation between these two species.