Joining S100 proteins and migration:for better or for worse, in sickness and in health

The vast diversity of S100 proteins has demonstrated a multitude of biological correlations with cell growth, cell differentiation and cell survival in numerous physiological and pathological conditions in all cells of the body. This review summarises some of the reported regulatory functions of S100 proteins (namely S100A1, S100A2, S100A4, S100A6, S100A7, S100A8/S100A9, S100A10, S100A11, S100A12, S100B and S100P) on cellular migration and invasion, established in both culture and animal model systems and the possible mechanisms that have been proposed to be responsible. These mechanisms involve intracellular events and components of the cytoskeletal organisation (actin/myosin filaments, intermediate filaments and microtubules) as well as extracellular signalling at different cell surface receptors (RAGE and integrins). Finally, we shall attempt to demonstrate how aberrant expression of the S100 proteins may lead to pathological events and human disorders and furthermore provide a rationale to possibly explain why the expression of some of the S100 proteins (mainly S100A4 and S100P) has led to conflicting results on motility, depending on the cells used. © 2013 Springer Basel

Studies of the transcription of viral genome in adenovirus 5 transformed cells.

Transcription of the human adenovirus 5 genome in transformed rat embryo cells (DFK3) was investigated using two different approaches. Preferential digestion of transcribed viral sequences by DNase I was analysed using kinetics of renaturation of 32P-labeled Ad5 HpaI restriction fragments in the presence of material which was stable after nuclease treatment. The second approach was the hybridization of 32P-labeled nuclear RNA from transformed cells with Ad5 restriction fragments which were attached to a nitrocellulose filter. These two methods gave similar results. It was found that not all integrated regions of the Ad5 genome are active in transformed cells. 2,5 copies of the HpaI-E fragment of Ad5 DNA were found in transformed DFK3 cell line. Nuclear RNA from these cells hybridized to HpaI-E fragment of Ad5 DNA, but only about half of sequences of the integrated HpaI-E fragment was sensitive to DNase I digestion

The structure and expression of two defective adenovirus 2/simian virus 40 hybrids

Two new defective adenovirus 2/simian virus 40 hybrids (Ad2+ D1 and Ad2 + D2) have been isolated from the population known as Ad2++ HEY (Lewis & Rowe, 1970). The structure of their genomes has been determined by analysis with restriction enzymes, hybridization and electron microscopy. The DNA of Ad2+D1 is almost equal in size to that of its helper, adenovirus 2. It contains an insertion of simian virus 40 (SV40) sequences 3.2 × 103 bases long in place of the 3.5 × 103 base segment of adenovirus 2 DNA which maps between 0.64 and 0.74 fractional genome lengths from the left end of the viral DNA. The insertion which encompasses the entire early region of the SV40 genome, comprises the segment of DNA lying between positions 71 and 10: it is oriented with the sequences coding for the carboxy terminus of the A gene protein to the left. The DNA of Ad2+D2 is shorter than that of adenovirus 2 by approximately 6%. The segment mapping between 0.76 and 0.96 fractional genome lengths from the left end of adenovirus 2 DNA is absent: in its place is inserted a stretch of DNA, 5.0 × 103 bases in length which comprises all the sequences of the SV40 genome apart from those lying between map positions 54 and 63. By contrast to Ad2+D1, the ‘early’ SV40 sequences in Ad2+D2 are transcribed from left to right. RNA complementary to the ‘early’ sequences of the E strand of SV40 DNA is present in the cytoplasm at both early and late times after infection of monkey cells by Ad2+D1. No transcripts of the viral L strand were detected. SV40-specific RNA was found in the cytoplasm of cells infected with Ad2+D2, only at late times after infection. The most abundant species was complementary to the coding sequences of the E strand of SV40 DNA. Transcripts of the L strand were also present, but in significantly lesser quantity. Proteins related to SV40-specific T antigen were detected in infected cells by immunofluorescence and by immunoprecipitation with sera from hamsters bearing tumors induced by SV40. The major polypeptide precipitated from extracts of cells infected with Ad2+D1 migrated through sodium dodecyl sulfate/polyacrylamide gels at the same rate as SV40 T antigen: its apparent molecular weight is 96,000. A significantly larger polypeptide (Mr = 115,000) is precipitated from extracts of cells infected by Ad2+D2. Consideration of the structures of the genomes of Ad2+D1 and Ad2+D2 leads us to believe that Ad2+D1 may have arisen by recombination between members of the Ad2++HEY hybrid pool and adenovirus 2, while Ad2+D2 was most likely generated by recombination events between adenovirus 2 and free SV40

Possible co-regulation of genes associated with enhanced progression of mammary adenocarcinomas.

Tumor progression is a multistep process in which alterations in the expression of numerous gene products may give rise to highly malignant cellular variants. In the present study, we analyzed the differential expression of several genes in cellular variants of mammary adenocarcinomas with high or low malignancy potential, which originated in a common ancestor. To assess the generality of our findings, high and low malignancy variants were derived from two different mammary adenocarcinoma cell lines, namely DA3 and CSML cells. Of major importance is the fact that the differences between high- and low-malignancy variants observed in one system of mammary adenocarcinoma cells (DA3 cells) were identically reproduced in the other system of mammary adenocarcinoma cells (CSML cells). The high malignancy variants of tumors both DA3-high and CSML-high (previously called CSML-100), expressed higher levels of factors that induce monocyte migration than the low malignancy DA3-low and CSML-low (previously called CSML-0) variants. In addition, it was found that DA3-high and CSML-high cell variants expressed higher levels of monocyte chemoattractant protein-1 (MCP-1), interleukin-6 (IL-6) and matrix metalloproteinases (MMPs) than the low malignancy variants (DA3-low and CSML-low). These results suggest that MCP-1, IL-6 and MMPs potentially contribute to mammary adenocarcinoma progression and that their expression is regulated by a common pathway. The expression of MCP-1, IL-6 and MMPs in both DA3-high and CSML-high cells was up-regulated by tumor necrosis factor alpha (TNFalpha). The fact that TNFalpha exerted similar effects on the expression of these three factors in both cell systems raises the possibility of a coordinated co-regulation of tumor-promoting factors

Twenty six-week exposure to 2 amino-3 methylimidazo [4,5-f]quinoline (IQ) does not significantly increase the incidence of tumours in HMGCR/mts1 tg579 transgenic mice

HMGCR/mts1 tg579 transgenic mice were designed to direct the expression of metastasis-promoting mts1  (S100A4) gene to all the tissues. In order to test the usefulness of this mouse model for carcinogenicity  tests shorter than that recommended by OECD guideline nr. 451, HMGCR/mts1 tg579 transgenic and  C57BL/6ByA (wild type) mice (15 males and 15 females of each genotype per group) received either a  control diet for 53 weeks or a control diet plus 0.03% 2-amino-3 methylimidazo[4,5-ƒ]quinoline  (IQ) for 26 weeks and a control diet for the remaining 27 weeks. IQ is a food mutagen with a carcinogenic  effect in non-human primates and rodents. IQ is a liver carcinogen and also causes lung tumours and  tumours of the forestomach in mice. Body weight gain and feed intake were decreased (p<0.05) during IQ  feeding in IQ-dosed mice of both genotypes and sexes. The daily dose of IQ, as calculated based on the  feed intake, was 43 and 46 mg/kg bw in HMGCR/mts1 tg579 transgenic males and females, and 43 and  45 mg/kg bw in C57BL/6ByA males and females. The survival rates of HMGCR/mts1 tg579 transgenic  mice were 100% for males and 93% for females in the control group, and 93% for both sexes in the IQtreated  group. The survival rates of C57BL/6ByA mice of both sexes were 100% in the control group and  93% in the IQ-treated group. Non-neoplastic lesions were found in all groups, except for HMGCR/mts1  tg579 transgenic control males, primary in the liver and were of various type but of single incidence with  not statistically significant difference between controls and IQ-treated groups of both genotypes and sexes.  Pre-neoplastic lesions were observed preferentially in the liver in IQ-treated HMGCR/mts1 tg579 transgenic  animals of both sexes. The total number of animals with tumours was: in HMGCR/mts1 tg579 transgenic  mice: males - 0/15 and 3/15, females - 2/14 and 1/15 and in C57BL/6ByA: males - 0/15 and 1/15,  females - 1/15 and 4/15, in control and IQ-treated animals, respectively. The primary tumours recorded in  HMGCR/mts1 tg579 transgenic mice were: one pleomorphic malignant lymphoma and one histiosarcoma  in the female control group, one liver hemangiosarcoma, one colon adenocarcinoma, and one malignant  lymphoma/lympholytic in IQ-treated males, and one colon adenoma in IQ-treated females. The primary  tumours recorded in C57BL/6ByA mice were: one histiocytic sarcoma in control females, one colon adenoma  in IQ-treated males, one colon adenocarcinoma, one pleomorphic malignant lymphoma, one malignant  lymphoma/lymphocytic, one thymic lymphoma, and one histiocytic sarcoma in IQ-treated females.  In conclusion, IQ feeding did not statistically significantly increase the incidence of tumours in  HMGCR/mts1 tg579 transgenic and C57BL/6ByA mice in this limited bioassay. The results in HMGCR/mts1  tg579 transgenic mice obtained under current experimental conditions suggest that 53 weeks may be not a  sufficient time span to demonstrate a carcinogenic potential of a test compound in this mouse model.

Transformation of rat cells by the hybrid virus Ad2(2+) HEY

A set of four isogenic rat cell lines transformed by Ad22+ HEY have been studied. While all of the cell lines synthesize SV40 T antigen, only one expresses adenovirus 2 T antigen: none expresses SV40 V antigen or adenovirus 2 fibre antigen. Three cell lines contain 1 to 2 virus equivalents of SV40 and adenoviral sequences per diploid quantity of rate cell DNA and the fourth line contains five copies of SV40 and 20 copies of the adenovirus genome. At least three of the cell lines contain DNA sequences from the helper adenovirus 2 in addition to sequences from the Ad2+ HEY genome. The patterns of integrated virus sequences are complex suggesting multiple insertions of both adenovirus and SV40 DNA sequences. SV40 can be rescued from three cell lines by fusion with permissive cells