Knowledge and attitude of women regarding the human papillomavirus (HPV) infection, its relationship to cervical cancer and prevention methods

This study aimed to determine knowledge and attitude of women to HPV and its association with cervical cancer and prevention methods. In a cross-sectional study, 500 women, aged between 20 and 50 presenting to local health centers in Tehran, were asked about demographic factors and questioned about cervical cancer, HPV, and prevention methods. Responses were tabulated and summarized. Although knowledge of HPV, its relation to cervical cancer and prevention methods among Iranian women is not enough, their attitude towards education in this regards is extremely high. The results reflect the need of advertising and educational programs for public about HPV prevention methods, to reduce the prevalence of this infection and its severe consequences.

Primitive neuroectodermal tumor of the cervix: a case report

Introduction

Peripheral primitive neuroectodermal tumor of the cervix uteri is extremely rare. Between 1987 and 2010, there were only nine cases reported in the English literature, with considerably different management policies.

Case presentation

A 45-year-old Iranian woman presented to our facility with a primitive neuroectodermal tumor of the cervix uteri. Her clinical stage IB2 tumor was treated successfully with chemotherapy. Our patient underwent radical hysterectomy. There was no trace of the tumor after four years of follow-up.

Conclusions

According to current knowledge, primitive neuroectodermal tumors belong to the Ewing's sarcoma family, and the improvement of treatment outcome in our patient was due to dose-intensive neoadjuvant chemotherapy, surgery and consolidation chemotherapy in accordance with the protocol for bony Ewing's sarcoma.

Comparison of Pap smear, visual inspection with acetic acid, and digital cervicography as cervical screening strategies

PURPOSE

To compare the sensitivity, specificity, positive and negative predictive values (PPV and NPV), and accuracy of Pap smear, visual inspection with acetic acid (VIA) and digital cervicography (DC).

METHODS

This is a cross-sectional study on 100 women in the age group of 20-60 years, sequentially using the Pap test, the VIA, and the DC for screening. All women underwent colposcopic biopsy as the gold standard in comparing the methods.

RESULTS

Of the total of 100 women with the mean age 36.0 years, 17 cases were recognized positive for abnormal cervical cell by gold standard. The sensitivity, specificity, PPV, NPV, and accuracy of the Pap test, the VIA, and the DC were 23.5, 100, 100, 86.5, and 87%; 62.5, 98.8, 90.9, 93.2, and 92.9%; and 46.7, 97.6, 77.8, 91, and 89.8%, respectively, for cervical neoplasia.

CONCLUSIONS

The Pap test had low sensitivity but high specificity, whereas VIA had a high sensitivity in addition to being easy and low-cost. Adjuvant methods of screening such as VIA can be a valuable alternative to the Pap test for cervical cancer screening in low-resource settings.

RACK-1 overexpression protects against goniothalamin-induced cell death

Goniothalamin, a styryllactone, has been shown to induce cytotoxicity via apoptosis in several tumor cell lines. In this study, we have examined the potential role of several genes, which were stably transfected into T-cell lines and which regulate apoptosis in different ways, on goniothalamin-induced cell death. Overexpression of full-length receptor for activated protein C-kinase 1 (RACK-1) and pc3n3, which up-regulates endogenous RACK-1, in both Jurkat and W7.2 T cells resulted in inhibition of goniothalamin-induced cell death as assessed by MTT and clonogenic assays. However, overexpression of rFau (antisense sequence to Finkel-Biskis-Reilly murine sarcoma virus-associated ubiquitously expressed gene) in W7.2 cells did not confer resistance to goniothalamin-induced cell death. Etoposide, a clinically used cytotoxic agent, was equipotent in causing cytotoxicity in all the stable transfectants. Assessment of DNA damage by Comet assay revealed goniothalamin-induced DNA strand breaks as early as 1 h in vector control but this effect was inhibited in RACK-1 and pc3n3 stably transfected W7.2 cells. This data demonstrate that RACK-1 plays a crucial role in regulating cell death signalling pathways induced by goniothalamin.

PML involvement in the p73-mediated E1A-induced suppression of EGFR and induction of apoptosis in head and neck cancers

Epidermal growth factor receptor (EGFR) tyrosine kinase is commonly overexpressed in human cancers; however, the cellular mechanisms regulating EGFR expression remain unclear. p53, p63 and p73 are transcription factors regulating many cellular targets involved in controlling the cell cycle and apoptosis. p53 activates EGFR expression, whereas TAp63 represses EGFR transcription. The involvement of p73 in the regulation of EGFR has not been reported. Here, a strong correlation between EGFR overexpression and increased levels of the oncogenic DeltaNp73 isoform in head and neck squamous cell carcinoma (HNSCC) cell lines was observed. Ectopic expression of TAp73, particularly TAp73beta, resulted in suppression of the EGFR promoter, significant downregulation of EGFR protein and efficient induction of cell death in all six EGFR-overexpressing HNSCC cell lines. EGFR overexpression from a heterologous LTR promoter protected lung cancer cells from TAp73beta-induced EGFR suppression and apoptosis. Expression of TAp73beta efficiently induced promyelocytic leukaemia (PML) protein expression and PML knockdown by shRNA attenuated the downregulation of EGFR and induction of apoptosis by p73 in HNSCC cells. Furthermore, PML was found to be important for E1A-induced suppression of EGFR and subsequent killing of HNSCC cells. Our data therefore suggest a novel pathway involving PML and p73 in the regulation of EGFR expression.

Fetal and embryonic hemoglobins in erythroblasts from fetal blood and fetal cells enriched from maternal blood in pregnancies complicated by maternal diabetes mellitus

OBJECTIVES

To determine whether there is a delay or reversal in switch mechanisms from embryonic (epsilon and zeta) to fetal (gamma) hemoglobins accompanying the erythroblastosis in fetuses of diabetic mothers, and whether the increased erythroblast count in the fetal blood is associated with an increase in fetomaternal cell trafficking.

MATERIALS AND METHODS

Fetal and maternal blood samples were obtained from 11 fetuses and five pregnant women in pregnancies complicated by maternal diabetes mellitus. Blood samples were also taken as controls from 35 fetuses and 33 mothers. Fetal erythroblasts were isolated by triple density gradient centrifugation and magnetic cell sorting with anti-CD71 antibody. Fluorescent antibodies were used to immunostain for gamma (gamma), epsilon (epsilon) and zeta (zeta) hemoglobin chains. In the maternal samples, fluorescence in situ hybridization for X and Y chromosomes was also carried out, to confirm the presence and proportion of enriched fetal cells from the maternal blood.

RESULTS

In both fetal and maternal blood the median percentages of erythroblasts positive for gamma-globin, epsilon-globin and zeta-globin chains were significantly higher in fetuses of diabetic mothers compared to controls (fetus, gamma-globin, 76 vs. 64%, p < 0.0001; epsilon-globin, 4 vs. 0%, p < 0.0001; zeta-globin, 4 vs. 0%; p < 0.0001; mother, gamma-globin, 14 vs. 1%, p < 0.0005; epsilon-globin, 0.25 vs. 0%, p < 0.0003; zeta-globin, 0.2 vs. 0%, p < 0.0003). The median percentage of cells with Y signals in maternal blood was also higher in diabetic pregnancies compared to normal controls (7.5 vs. 1%, p < 0.002).

CONCLUSIONS

The findings suggest that the fetal erythroblastosis in diabetic pregnancies is accompanied by a delay in the switch from embryonic to fetal hemoglobin chains. In addition, it is associated with an increase in fetomaternal cell trafficking.

The second to fourth digit ratio (2D:4D) in women with and without human papillomavirus and cervical dysplasia

Persistent infection with human papillomavirus (HPV) is associated with a high risk of cervical intraepithelial neoplasia (CIN) and disease progression is influenced by host hormonal factors. The role of fetal exposure to sex steroids has not been explored. The study compared the second to fourth digit ratio (2D:4D), a marker of exposure to fetal androgens, among women with and without HPV and CIN. Data were available from two studies in which HPV, 2D:4D and descriptive variables were assessed cross-sectionally at sexual health clinics. One study (case-control) also assessed cervical smears or biopsies, and some women were retested for persistent HPV. Using these data, 2D:4D was compared among groups defined by cervical smear and HPV result. The cross-sectional data included 90 adolescents and 240 nonadolescents. White women had a significantly higher 2D:4D than other ethnic groups. In the case-control analysis (n = 263), after controlling for ethnicity, women who developed CIN were significantly more likely to have a higher 2D:4D compared with HPV-negative women. A similar, nonsignificant trend was observed among women with a persistent HPV infection.

CONCLUSION

Lower fetal androgen exposure may predispose to persistent HPV and increased risk of CIN.

p400 function is required for the adenovirus E1A-mediated suppression of EGFR and tumour cell killing

We have recently shown that E1A protein of human adenovirus downregulates epidermal growth factor receptor (EGFR) expression and induces apoptosis in head and neck (HNSCC) and lung cancer cells independently of their p53 status. E1A has five isoforms of which the major ones E1A12S and E1A13S regulate transcription of cellular genes by binding to transcriptional modulators such as pRB, CtBP, p300 and p400. In this study, we have identified E1A12S isoform to have the highest effect on EGFR suppression and induction of apoptosis in HNSCC cells. Similar to Ad5, E1A12S from human adenovirus types 2, 3, 9 and 12 suppressed EGFR, whereas E1A12S of adenovirus types 4 and 40 had no effect on EGFR expression. Using deletion mutants of E1A12S we have shown that interaction of E1A with p400, but not p300 or pRB, is required for EGFR suppression and apoptosis. Inhibition of p400 by short hairpin RNA confirmed that HNSCC cells with reduced p400 expression were less sensitive to E1A-induced suppression of EGFR and apoptosis. p300 function was shown to be dispensable, as cells expressing E1A mutants that are unable to bind p300, or p300 knockout cells, remained sensitive to E1A-induced apoptosis. In summary, this study identifies p400 as an important mediator of E1A-induced downregulation of EGFR and apoptosis.

International Society for Cell and Gene Therapy of Cancer: 2005 meeting in Shenzhen, China

The 2005 International Society for Cell and Gene Therapy of Cancer (ISCGT) Congress was held in Shenzhen, China (www.iscgtchina2005.com) from December 9th-11th 2005. Here, we describe a representation of the most seminal presentations providing an overview of the progress in the field of cancer gene therapy including the successful introduction of the first approved gene therapy drug.

The IL-10 -1082G polymorphism is associated with clearance of HPV infection

The role of cytokines in protecting against human papillomavirus (HPV) and HPV-associated disease is not fully understood. We compared the frequency of the interleukin (IL)-10 polymorphism (G allele) at position --1082 and the distribution of GG/GA/AA genotypes among 116 HPV-positive women, grouped according to their cervical cytological profiles, with 119 HPV-negative controls with normal smears. No difference was observed in genotype frequency between the groups. Among women in the HPV-positive, smear-normal group, who were re-tested for HPV after 12 months, there was a significant inverse association between presence of at least one variant G allele (high activity) and HPV persistence (OR per G allele = 0.082 [95% CI 0.009-0.73], P= 0.001; after controlling for ethnicity). This association remained significant after controlling for age, smoking and hormonal contraception (OR = 0.028 [95% CI 0.001-0.66], P= 0.001). This preliminary study suggests that higher levels of IL-10 may prevent cervical neoplasia through their role in eliminating HPV.

Future acceptance of adolescent human papillomavirus vaccination: a survey of parental attitudes

The main target group for vaccination against human papillomavirus (HPV), the sexually transmitted virus that causes cervical cancer, will be young adolescents. We undertook a population-based survey to assess parental consent and potential HPV vaccine uptake in eight secondary schools using stratified randomisation according to school type and ethnicity. Our results suggest that in socially and ethnically mixed populations such as Manchester, an HPV vaccine uptake rate of 80% may be achievable if the vaccine is perceived to be safe and effective. However, most parents lack knowledge about HPV and some are concerned about sexual health issues that would arise as part of a HPV vaccine programme. It will be important to raise general awareness of the role of HPV in cervical cancer without stigmatizing the vaccine.

Influence of interleukin-4 on the phenotype and function of bone marrow-derived murine dendritic cells generated under serum-free conditions

Murine bone marrow-derived dendritic cells (DC) can be generated by culture in the presence of granulocyte/macrophage colony-stimulating factor (GM-CSF) alone or GM-CSF in conjunction with interleukin-4 (IL-4). However, these two culture methods result in the production of heterogeneous DC populations with distinct phenotypic and stimulatory properties. In this study, we investigated the properties of DC generated under serum-free conditions in the presence or absence of IL-4 and compared their yield and phenotype to that of DC generated in the presence of fetal calf serum (FCS) (+/-IL-4). We did not observe a significant difference in the total cell yield between these four culture conditions, although the proportion of CD11c+ DC in cultures that received FCS was higher than that of their counterparts generated under serum-free conditions. Also, the four culture conditions generated CD11c+ DC with comparable levels of major histocompatibility complex (MHC) class II, CD40, CD80 and CD86 expression, with the exception of cells cultured under serum-free conditions in the absence of IL-4, which displayed suboptimal levels of these markers. Moreover, we compared the functional and stimulatory properties of DC generated under serum-free conditions in the presence or absence of IL-4. DC cultured in the presence of IL-4 were stronger stimulators of allogeneic splenocytes in a primary mixed lymphocyte reaction (MLR) and of naive antigen-specific OT-II transgenic T cells when pulsed with the class II ovalbumin (OVA)323-339 peptide or whole OVA protein than DC cultured in the absence of IL-4. However, both DC populations displayed a similar capacity to take up fluorescein isothiocyanate (FITC)-albumin by macropinocytosis and FITC-Dextran by the mannose receptor and to secrete IL-12 in response to stimulation with lipopolysaccharide (LPS) or an agonistic anti-CD40 monoclonal antibody. Therefore, we conclude that although both DC culture methods result in the production of DC with similar functional abilities, under serum-free conditions, DC cultured in GM-CSF and IL-4 show an increased stimulatory potential over DC cultured in GM-CSF alone. This is an important consideration in the design of experiments where DC are being exploited as immunotherapeutic vaccines.

Fetal erythroblasts in maternal blood in relation to gestational age

OBJECTIVES

To determine the distribution of fetal erythroblasts in the maternal circulation at different gestations.

MATERIALS AND METHODS

Maternal blood was obtained from 152 normal singleton pregnancies at 11-40 weeks of gestation. Fetal erythroblasts were isolated using triple density gradient separation and anti-CD71 magnetic cell sorting techniques. The enriched erythroblasts were stained with Kleihauer-Giemsa and with fluorescent antibodies for the zeta (zeta), epsilon (epsilon) and gamma (gamma) globin chains. The percentage of fetal cells positive for each stain was calculated. Fluorescence in situ hybridization for X and Y chromosomes was also performed. Comparison was made in the proportion of positive fetal erythroblasts among the different gestational ages.

RESULTS

The proportion of erythroblasts stained positive with gamma-globin chain and Kleihauer-Giemsa decreased with gestation from a median of 2% at 11 weeks to 0.5% at 40 weeks. Similarly, there was a decrease in the percentage of Y-signal-positive cells from 1% at 11 weeks to 0.3% at 40 weeks. The proportion of enriched fetal erythroblasts stained positive with zeta- and epsilon-globin chains decreased exponentially from respective medians of 0.6% and 1.5% at 11 weeks to zero after 19 weeks and 24 weeks.

CONCLUSION

In normal singleton pregnancy the percentage of fetal erythroblasts enriched from maternal blood decreases with gestation.

Assessment of efficacy of cell separation techniques used in the enrichment of foetal erythroblasts from maternal blood: triple density gradient vs. single density gradient

The aim of this study was to determine the efficacy of cell separation with single density and triple density-gradient techniques in the yield of foetal erythroblasts isolated from maternal blood. Maternal blood was obtained from 20 singleton pregnancies at 11-14 weeks of gestation immediately before foetal karyotyping by chorionic villus sampling. In each woman, the blood sample was divided into two portions; one portion was used for single density-gradient separation and the other, for triple density-gradient separation. Magnetic cell sorting (MACS) was subsequently performed with anti-CD71/antiglycophorin-A. The enriched erythroblasts were stained with Kleihauer-Giemsa and with fluorescent antibodies for the gamma, epsilon and zeta globin chains. The percentage of foetal cells positive for each stain was calculated. Fluorescence in situ hybridization (FISH) for X- and Y-chromosomes was also performed. Comparison was made in the proportion of enriched foetal cells between the two separation methods for each CD71 and glycophorin-A (GPA) antibody. The percentage of erythroblasts enriched from maternal blood that stained positive for gamma, epsilon and zeta globin chains and with Kleihauer-Giemsa was significantly higher in the triple density-gradient separation fractions compared with the single density-gradient fractions with both anti-CD71 and GPA MACS. FISH analysis for the Y-chromosome confirmed the increase in foetal cell proportion in the triple density-gradient samples. Isolation of foetal erythroblasts from maternal blood using triple density-gradient separation and MACS is more effective with regard to foetal cell yield and purity than single density-gradient separation and MACS.

Functional expression cloning reveals proapoptotic role for protein phosphatase 4

Functional expression cloning strategies are highly suitable for the analysis of the molecular control of apoptosis. This approach has two critical advantages. Firstly, it eliminates prior assumptions about the properties of the proteins involved, and, secondly, it selectively targets proteins that are causally involved in apoptosis control and which affect the crucial cellular decision between survival and death. The application of this strategy to the isolation of cDNAs conferring resistance to dexamethasone and gamma-irradiation resulted in the isolation of a partial cDNA for the catalytic subunit of protein phosphatase 4 (PP4). Cells transfected with this partial cDNA in an expression vector downregulated PP4 and were resistant to both dexamethasone and UV radiation, as demonstrated by both membrane integrity and colony-forming assays. These observations suggest that PP4 plays an important proapoptotic role in T lymphocytes.

Fetal and embryonic hemoglobins in erythroblasts from fetal blood and fetal cells enriched from maternal blood in fetal anemia

BACKGROUND AND OBJECTIVES

To determine whether there is a delay or reversal in switch mechanisms from embryonic (e and z) to fetal (g) hemoglobins accompanying the erythroblastosis of anemic fetuses and whether an increased erythroblast count in fetal blood is associated with an increase in feto-maternal cell trafficking.

DESIGN AND METHODS

Fetal and maternal blood samples were obtained from 10 cases with rhesus isoimmunization and 2 cases with maternal Parvo-B19 virus at 19-33 weeks' gestation. Blood samples were also taken as controls from 61 fetuses and 86 mothers. Fetal erythroblasts were isolated by triple density gradient centrifugation and magnetic cell sorting with CD71 antibody. Fluorescent antibodies were used to immuno-stain for zeta (z), epsilon (e) and gamma (g) hemoglobin chains. In the maternal samples, fluorescence in situ hybridization (FISH) for X and Y chromosomes was also carried out to confirm the presence and proportion of the enriched fetal cells from maternal blood.

RESULTS

In both fetal and maternal blood the percentage of erythroblasts positive for g-globin chain was significantly higher in the anemic fetuses compared to the controls (fetal blood, p<0.001, R=0.91; maternal blood, p<0.001, R=0.56), but there was no significant difference in expression of the e and z-chains. The percentage of cells with Y-signals was also higher in the maternal samples of anemic fetuses compared to normal controls (p<0.001, R=0.56).

INTERPRETATION AND CONCLUSIONS

These findings suggest that the erythroblastosis of anemic fetuses is not accompanied by a delay or a reversal in switch from embryonic to fetal hemoglobin chains. Severe fetal anemia is associated with an increase in feto-maternal cell trafficking.

Selective cleavage of BLM, the bloom syndrome protein, during apoptotic cell death

Bloom syndrome (BS) is an autosomal recessive disorder characterized by a high incidence of cancer and genomic instability. BLM, the protein defective in BS, is a RECQ-like helicase that is presumed to function in mammalian DNA replication, recombination, or repair. We show here that BLM, but not the related RECQ-like helicase WRN, is rapidly cleaved in cells undergoing apoptosis. BLM was cleaved to 47- and 110-kDa major fragments, with kinetics similar to the apoptotic cleavage of poly(A)DP-ribose polymerase. BLM cleavage was prevented by a caspase 3 inhibitor and did not occur in caspase 3-deficient cells. Moreover, recombinant BLM was cleaved to 47- and 110-kDa fragments by caspase 3, but not caspase 6, in vitro. The caspase 3 recognition sequence (412)TEVD(415) was verified by mutating aspartate 415 to glycine and showing that this mutation rendered BLM resistant to caspase 3 cleavage. Cleavage did not abolish the BLM helicase activity but abolished BLM nuclear foci and the association of BLM with condensed DNA and the insoluble matrix. The results suggest that BLM, but not WRN, is an early selected target during the execution of apoptosis.

Distribution of fetal and embryonic hemoglobins in fetal erythroblasts enriched from maternal blood

BACKGROUND AND OBJECTIVES

To determine the distribution of embryonic and fetal hemoglobin chains in fetal erythroblasts isolated from maternal blood in the first trimester of pregnancy and establish the feasibility of using these chains as markers for fetal cell identification.

DESIGN AND METHODS

Maternal blood was obtained from 187 singleton pregnancies at 11-14 weeks of gestation immediately before fetal karyotyping by chorionic villus sampling. In all cases included in this study the fetal karyotype was normal. Fetal erythroblasts were isolated using triple density gradient separation and anti-CD71 magnetic cell sorting techniques. The enriched erythroblasts were stained with Kleihauer-Giemsa and with fluorescent antibodies for the zeta (z), epsilon (e) and gamma (g) globin chains. The percentage of fetal cells positive for each stain was calculated. Fluorescent in situ hybridization (FISH) for X and Y chromosomes was also performed. Comparison was made with the percentage of cells with positive Y-signal FISH in pregnancies with male fetuses.

RESULTS

The percentage of fetal erythroblasts stained positive was 37% for the z and 95% for both e and g globin chains, as well as the Kleihauer-Giemsa staining. There was a significant association between the Kleihauer-Giemsa stained cells and those stained with e and g globin chains. There was also an association between cells with Y-signals and those stained with e and g globin chains.

INTERPRETATION AND CONCLUSIONS

Embryonic hemoglobin chains can be detected in the enriched fetal erythroblasts, with higher percentages of the e rather than the z globin chains. These chains are therefore potentially unique markers to be used in the identification of cells of fetal origin from maternal blood for prenatal diagnosis of genetic and chromosomal abnormalities.

Streptavidin paramagnetic particles provide a choice of three affinity-based capture and magnetic concentration strategies for retroviral vectors

Three strategies have been designed to concentrate infectious retroviral vectors from the supernatants of human- (HT1080) and murine- (NIH 3T3) based packaging cells. Streptavidin-conjugated paramagnetic particles in conjunction with (i) antibodies directed against murine fibronectin, (ii) biotinylated lectins, or (iii) biotin-modified packaging cell-surface proteins allow affinity-mediated magnetic concentration of retroviral vectors. Retroviral titers (assayed by colony formation of human myeloid K562 cells) are increased by 1-4 x 10(3)-fold after volume reductions of only 125-fold. Using these procedures, preparations of 5 x 10(8) cfu/ml are routinely made from relatively low-titer (2-5 x 10(5) cfu/ml) starting material. High-titer (paramagnetic) retroviral vector preparations can be used for magnetic field-dependent retroviral infection in vitro. Magnetic field-dependent localization such as this may enable the in vivo administration of formulations that concentrate retroviral infection to the required target tissues and organs.

An iron-regulated ferric reductase associated with the absorption of dietary iron

The ability of intestinal mucosa to absorb dietary ferric iron is attributed to the presence of a brush-border membrane reductase activity that displays adaptive responses to iron status. We have isolated a complementary DNA, Dcytb (for duodenal cytochrome b), which encoded a putative plasma membrane di-heme protein in mouse duodenal mucosa. Dcytb shared between 45 and 50% similarity to the cytochrome b561 family of plasma membrane reductases, was highly expressed in the brush-border membrane of duodenal enterocytes, and induced ferric reductase activity when expressed in Xenopus oocytes and cultured cells. Duodenal expression levels of Dcytb messenger RNA and protein were regulated by changes in physiological modulators of iron absorption. Thus, Dcytb provides an important element in the iron absorption pathway.

Protein transduction: an alternative to genetic intervention?

Protein transduction, an emerging technology with potential applications in gene therapy, can best be described as the internalisation of proteins into the cell, from the external environment. This process relies on the inherent property of a small number of proteins and peptides of being able to penetrate the cell membrane. The transducing property of these molecules can be conferred upon proteins which are expressed as fusions with them and thus offers an alternative to gene therapy for the delivery of therapeutic proteins into target cells. This review describes the three most commonly used protein transduction vehicles; the antennapedia peptide, the herpes simplex virus VP22 protein and HIV TAT protein transduction domain. The future prospects for the application of this technology in gene therapy are also discussed.

Protein transduction: a new tool for the study of cellular ageing and senescence

Protein transduction can be described as the direct uptake by the cell of exogenous proteins/peptides or protein/peptide:chemical complexes, as a result of a specific property of the protein/peptide component. In this review, the three most widely studied protein transducing activities are described, with particular emphasis on the TAT protein transduction domain. Current progress in protein transduction technology suggests the potential development of a variety of molecular and cell biology tools that will enable researchers to by-pass conventional genetic routes for modulating the cells' biological activity, thus negating many of the problems associated with genetic intervention. The potential application of this class of molecule in the development of tools for the study of senescent populations is discussed.

Regulation of HGF/SF gene expression in MRC-5 cells by N-acetylcysteine

The effect of N-acetylcysteine (NAC) on levels of hepatocyte growth factor/scatter factor (HGF/SF) gene transcripts was investigated in the human lung embryonic fibroblast cell line, MRC-5. NAC increased expression of HGF/SF mRNA, in a dose- and time-dependent fashion, by a mechanism independent of glutathione synthesis but sensitive to oxidant stress induced by H(2)O(2). Using actinomycin D to block RNA synthesis, it was observed that NAC had no effect on the stability of the HGF/SF mRNA transcripts. NAC increased HGF/SF promoter activity in cells transiently transfected with chloramphenicol acetyltransferase (CAT) reporter genes driven by HGF/SF gene 5'-flanking sequences. Primer extension analysis demonstrated that NAC enhanced the expression of HGF/SF mRNA transcribed from the main transcription initiation site. Although the 5' flanking region of the HGF/SF gene contains a sequence at -1019 to -1011 with homology to the NF-kappaB response element, electrophoretic mobility shift assay demonstrated that this site did not bind nuclear factors in MRC-5 cells in the presence or absence of NAC. In contrast to the effect on HGF/SF mRNA, NAC did not increase HGF/SF protein production by MRC-5 cells.

Fusagene vectors: a novel strategy for the expression of multiple genes from a single cistron

Transduction of cells with multiple genes, allowing their stable and co-ordinated expression, is difficult with the available methodologies. A method has been developed for expression of multiple gene products, as fusion proteins, from a single cistron. The encoded proteins are post-synthetically cleaved and processed into each of their constituent proteins as individual, biologically active factors. Specifically, linkers encoding cleavage sites for the Golgi expressed endoprotease, furin, have been incorporated between in-frame cDNA sequences encoding different secreted or membrane bound proteins. With this strategy we have developed expression vectors encoding multiple proteins (IL-2 and B7.1, IL-4 and B7.1, IL-4 and IL-2, IL-12 p40 and p35, and IL-12 p40, p35 and IL-2 ). Transduction and analysis of over 100 individual clones, derived from murine and human tumour cell lines, demonstrate the efficient expression and biological activity of each of the encoded proteins. Fusagene vectors enable the co-ordinated expression of multiple gene products from a single, monocistronic, expression cassette.

Fetal and embryonic hemoglobins in erythroblasts of chromosomally normal and abnormal fetuses at 10-40 weeks of gestation

BACKGROUND AND OBJECTIVES

During fetal development a change in erythropoiesis from hepatic to medullary site occurs. In chromosomally abnormal fetuses this change is delayed. Hemoglobin production also undergoes developmental switches from embryonic to fetal hemoglobins in the first trimester of pregnancy. The aim of study was to determine the proportion of embryonic and fetal hemoglobins in fetal erythroblasts of chromosomally normal and abnormal fetuses at 10-40 weeks of gestation.

DESIGN AND METHODS

Fetal blood was obtained from 93 chromosomally normal and 19 abnormal fetuses at 10-40 weeks of gestation. Fetal erythroblasts were isolated by triple density gradient centrifugation and magnetic cell sorting with CD71 antibody. Fluorescent antibodies were used to immuno-stain for zeta (zeta), epsilon (epsilon) and gamma (gamma) hemoglobin chains.

RESULTS

The percentages of the positively stained cells were calculated. In chromosomally normal fetuses the percentage of erythroblasts expressing the zeta chain was 25% at 10 weeks but this decreased exponentially with gestation to less than 1% by 17 weeks. Similarly, the percentage of cells expressing the epsilon chain decreased from 97% at 10 weeks to less than 1% by 25 weeks. In contrast, expression of the gamma chain increased from about 30% at 10 weeks to 90% by 16 weeks and decreased thereafter to 60% at 40 weeks. In the abnormal fetuses, the percentage of erythroblasts expressing the zeta chain and the epsilon chain decreased to less than 1% by 23 and 28 weeks respectively, while maximum expression of the gamma chain was at about 22 weeks.

INTERPRETATION AND CONCLUSIONS

In the chromosomally abnormal group the pattern of change in the expression of the various hemoglobin chains during gestation was similar to that in the normal fetuses but was delayed by three to six weeks. These findings suggest that in fetuses with chromosomal abnormalities there is a developmental delay in the switch from embryonic to fetal hemoglobin chains.

Low-speed centrifugation of retroviral vectors absorbed to a particulate substrate: a highly effective means of enhancing retroviral titre

For many gene therapy applications the effective titre of retroviral vectors is a limiting factor both in vitro and in vivo. Purification and concentration of retrovirus from packaging cell supernatant can overcome this problem. To this end we have investigated a novel procedure which involves complexing retrovirus to a dense and particulate substrate followed by a short low-speed centrifugation. The study reported here uses heat-killed, formaldehyde fixed Staphylococcus aureus (Pansorbin) absorbed to PG13 derived retrovirus. This complex was then used to harvest retrovirus from packaging cell supernatant: centrifugation and washing of this complex allows the retrovirus to be both purified and concentrated. This procedure increases the effective titre of retrovirus by up to 7500-fold after an only 200-fold reduction in volume. The affinity of Pansorbin for retrovirus allows concentration regardless of its encoded genes and makes this protocol applicable to other popular packaging cells and envelope proteins. Possible explanations for the marked increase in titre of concentrated virus and the mechanism governing the complexing of retrovirus to Pansorbin are discussed.

A novel duodenal iron-regulated transporter, IREG1, implicated in the basolateral transfer of iron to the circulation

Iron absorption by the duodenal mucosa is initiated by uptake of ferrous Fe(II) iron across the brush border membrane and culminates in transfer of the metal across the basolateral membrane to the portal vein circulation by an unknown mechanism. We describe here the isolation and characterization of a novel cDNA (Ireg1) encoding a duodenal protein that is localized to the basolateral membrane of polarized epithelial cells. Ireg1 mRNA and protein expression are increased under conditions of increased iron absorption, and the 5' UTR of the Ireg1 mRNA contains a functional iron-responsive element (IRE). IREG1 stimulates iron efflux following expression in Xenopus oocytes. We conclude that IREG1 represents the long-sought duodenal iron export protein and is upregulated in the iron overload disease, hereditary hemochromatosis.

Local versus systemic interleukin-2: tumor formation by wild-type and B7-1-positive murine melanoma cells

Modification of murine K1735 melanoma cells to express the immune costimulator B7-1 had no effect on tumor formation in syngeneic mice. In contrast, <40% of mice inoculated with K1735 cells modified to secrete murine interleukin-2 (IL-2) formed tumors, and no tumors formed when the K1735 cells coexpressed both murine IL-2 and B7-1. However, administration of systemic recombinant human IL-2 had no detectable effect on the formation of tumors by the B7-1-expressing K1735 cells. By contrast, admixtures of IL-2-secreting and B7-1-expressing K1735 cells formed fewer tumors than either cell type alone. Murine IL-2 was effective only when secreted locally, because the IL-2-secreting cells inoculated into the right flank did not affect the growth of the B7-1-expressing cells inoculated into the opposite flank.

The human and mouse GATA-6 genes utilize two promoters and two initiation codons

GATA-6 has been implicated in the regulation of myocardial differentiation during cardiogenesis. To determine how its expression is controlled, we have characterized the human and mouse genes. We have mapped their transcriptional start sites and demonstrate that two alternative promoters and 5' noncoding exons are utilized. Both transcript isoforms are expressed in the same tissue-specific and developmental stage-specific pattern, and their ratio appears similar wherever examined. The more upstream noncoding exon showed a substantial degree of homology between the two mammalian species, suggesting a conserved regulatory function. Moreover, in transfection assays we show that elements within this exon act to promote its transcription. Positive regulatory elements that effect transcription from the more downstream exon were not apparent in this assay, revealing a regulatory distinction between the two promoters. We also demonstrate alternative initiator codon usage in both the human and mouse GATA-6 genes. Both isoforms of the protein are synthesized in vitro regardless of which 5' noncoding exon is present in the RNA, although the larger protein has greater transcriptional activation potential in transfection assays. Thus, GATA-6 function in the cell is controlled by a complex interplay of transcriptional and translational regulation.