Metastasis-inducing DNA Regulates the Expression of the Osteopontin Gene by Binding the Transcription Factor Tcf-4

Small 1,000-bp fragments of genomic DNA obtained from human malignant breast cancer cell lines when transfected into a benign rat mammary cell line enhance transcription of the osteopontin gene and thereby cause the cells to metastasize in syngeneic rats. To identify the molecular events underlying this process, transient cotransfections of an osteopontin promoter-reporter construct and fragments of one metastasis-inducing DNA (Met-DNA) have identified the active components in the Met-DNA as the binding sites for the T-cell factor (Tcf) family of transcription factors. Incubation of cell extracts with active DNA fragments containing the sequence CAAAG caused retardation of their mobilities on polyacrylamide gels, and Western blotting identified Tcf-4, beta-catenin, and E-cadherin in the relevant DNA complexes in vitro. Transfection of an expression vector for Tcf-4 inhibited the stimulated activity of the osteopontin promoter-reporter construct caused by transiently transfected active fragments of Met-DNA or permanently transfected Met-DNA. This stimulated activity of the osteopontin promoter-reporter construct is accompanied by an increase in endogenous osteopontin mRNA but not in fos or actin mRNAs in the transfected cells. Permanent transfection of the benign rat mammary cell line with a 20-bp fragment from the Met-DNA containing the Tcf recognition sequence CAAAG caused an enhanced permanent production of endogenous osteopontin protein in vitro and induced the cells to metastasize in syngeneic rats in vivo. The corresponding fragment without the CAAAG sequence was without either effect. Therefore, the regulatory effect of the C9-Met-DNA is exerted, at least in part, by a CAAAG sequence that can sequester the endogenous inhibitory Tcf-4 and thereby promote transcription of osteopontin, the direct effector of metastasis in this system.

Differential Modulation of Transcriptional Activity of Estrogen Receptors by Direct Protein-Protein Interactions with the T Cell Factor Family of Transcription Factors

Two major signaling pathways, those triggered by estrogen (E(2)) and by the Wnt family, interact in the breast to cause growth and differentiation. The estrogen receptors ER(alpha) and ER(beta) are activated by binding E(2) and act as ligand-dependent transcription factors. The effector for the Wnt family is the Tcf family of transcription factors. Both sets of transcription factors recognize discrete but different nucleotide sequences in the promoters of their target genes. By using transient transfections of reporter constructs for the osteopontin and thymidine kinase promoters in rat mammary cells, we show that Tcf-4 antagonizes and Tcf-1 stimulates the effects of activated ER/E(2). For mutants of the former promoter, the stimulatory effects of ER(alpha)/E(2) can be made to be dependent on Tcf-1, and for the latter promoter the effects of the T cell factors (TCFs) are dependent on ER/E(2). Direct interaction between ERs and Tcfs either at the Tcf/ER(alpha)-binding site on the DNA or in the absence of DNA is established by gel retardation assays or by coimmunoprecipitation/biosensor methods, respectively. These results show that the two sets of transcription factors can interact directly, the interaction between ERs and Tcf-4 being antagonistic and that between ERs and Tcf-1 being synergistic on the activity of the promoters employed. Since Tcf-4 is the major Tcf family member in the breast, it is suggested that the antagonistic interaction is normally dominant in vivo in this tissue.

Acquiescence in interviews with people who have mental retardation

Evidence for acquiescence (yea-saying) in interviews with people who have mental retardation is reviewed and the different ways it has been assessed are discussed. We argue that acquiescence is caused by many factors, each of which is detected differentially by these methods. Evidence on the likely causes of acquiescence is reviewed, and we suggest that although researchers often stress a desire to please or increased submissiveness as the must important factor, acquiescence should also be seen as a response to questions that are too complex, either grammatically or in the type of judgments they request. Strategies to reduce acquiescence in interviews are reviewed and measures that can be taken to increase the inclusiveness of interviews and self-report scales in this population suggested.

The influence of transforming growth factor-beta1 gene polymorphisms on the severity of gingival overgrowth associated with concomitant use of cyclosporin A and a calcium channel blocker

The purpose of this study was to determine whether the prevalence and severity of gingival overgrowth in renal transplant recipients concomitantly treated with cyclosporin and a calcium channel blocker was associated with functional polymorphisms within the signal sequence of the transforming growth factor-(TGF)beta1 gene.

The interleukin 1beta gene promoter polymorphism (-511) acts as a risk factor for psychosis in Alzheimer's dementia

The explanation for why some patients develop psychotic change in Alzheimer's disease (AD) is unclear. "Psychosis-modifier genes" may act in the setting of neurodegeneration to produce AD plus psychosis in a similar way to how genetic modulation during neurodevelopment leads to schizophrenia. Because there is increasing interest in the common disruption of cytokine pathways seen in both AD and schizophrenia, we tested the association between the functional interleukin-1beta -511 promoter polymorphism with delusions and hallucinations in AD. Significant associations between psychotic symptoms and the CC genotype (p = 0.001 - p = 0.043) and C allele (p = 0.014 vs p = 0.048) were found, thus confirming the previously noted increased risk in schizophrenia.

Hepatocyte growth factor (HGF) protects c-met-expressing Burkitt''s lymphoma cell lines from apoptotic death induced by DNA damaging agents

The relative sensitivity of neoplastic cells to DNA damaging agents is a key factor in cancer therapy. In this paper, we show that pretreatment of Burkitt's lymphoma cell lines expressing the c-met protooncogene with hepatocyte growth factor (HGF) protects them from death induced by DNA damaging agents commonly used in tumour therapy. This protection was observed in assays based on morphological assessment of apoptotic cells and DNA fragmentation assays. The protection was dose- and time-dependent — maximal protection requiring pre-incubation with 100 ng/ml HGF for 48 h. Western blotting analysis and flow cytometric studies revealed that HGF inhibited doxorubicin- and etoposide-induced decreases in the levels of the anti-apoptotic proteins Bcl-XL, and to a lesser extent Bcl-2, without inducing changes in the pro-apoptotic Bax protein. Overall, these studies suggest that the accumulation of HGF within the microenvironment of neoplastic cells may contribute to the development of a chemoresistant phenotype.

CAMP factor homologues in Propionibacterium acnes: a new protein family differentially expressed by types I and II

Analysis of the draft genome sequence of the opportunistic pathogen Propionibacterium acnes type strain NCTC 737 (=ATCC 6919) revealed five genes with sequence identity to the co-haemolytic Christie-Atkins-Munch-Peterson (CAMP) factor of Streptococcus agalactiae. The predicted molecular masses for the expressed proteins ranged from 28 to 30 kDa. The genes were present in each of the three recently identified recA-based phylogenetic groupings of P. acnes (IA, IB and 11), as assessed by PCR amplification. Conserved differences in CAMP factor gene sequences between these three groups were also consistent with their previous phylogenetic designations. All type IA, IB and 11 isolates were positive for the co-haemolytic; reaction on sheep blood agar. Immunoblotting and silver staining of SIDS-PAGE gels, however, revealed differential protein expression of CAMP factors amongst the different groups. Type IB and 11 isolates produced an abundance of CAMP factor 1, detectable by specific antibody labelling and silver staining of SDS-PAGE gels. In contrast, abundant CAMP factor production was lacking in type A isolates, although larger amounts of CAMP factor 2 were detectable by immunoblotting compared with type 11 isolates. While the potential role of the abundant CAMP factor 1 in host colonization or virulence remains to be determined, it should be noted that the type strain of P. acnes used in much of the published literature is a type A isolate and is, therefore, lacking in this attribute.