Conditionally replicating adenovirus therapy utilizing bone sialoprotein promoter (Ad-BSP-E1a) in an in vivo study of treating androgen-independent intraosseous prostate cancer

Background

Adenoviral based gene therapy has been used in clinical trials in control of advanced prostate cancer. In this study, a promising conditionally replicating adenovirus (CRAd) driven by a tissue specific bone sialoprotein promoter in controlling prostate cancer both in vitro and in vivo is demonstrated.

Methods

C4-2B, an androgen-independent prostate cancer cell line, was treated with PBS, Ad-BSP-TK, or the Ad-BSP-E1a in vitro, and in subcutaneous and intraosseous xenographs. Cell proliferation, PSA level in condition medium, tumor volume, and/or serum PSA were followed.

Results

The growth of C4-2B and the PSA production was dramatically suppressed by Ad-BSP-E1a at very low dosage (0.3 MOI) compared with PBS and Ad-BSP-TK treatment in vitro. In the subcutaneous model, the tumor volume was significantly lower statistically in the Ad-BSP-E1a treated group than the Ad-BSP-TK control group (P = 0.02). In the intraosseous model, the mice treated in the Ad-BSP-E1a treatment group demonstrated a significant lower PSA compared to that in the control group (P < 0.01) at week 8 and week 16 post-treatment.

Conclusions

The CRAd Ad-BSP-E1a revealed potential in treating prostate cancer in this model system. Using viral or none-viral mediated gene therapy to treat prostate carcinoma continues to be a potential avenue to treat afflicted men with prostate cancer.     

人骨涎蛋白在大肠杆菌中的表达

目的在大肠杆菌中表达骨涎蛋白(BSP).方法构建BSP-PBV220表达载体,重组子以大肠杆菌DH5α为宿主菌进行诱导表达.结果工程菌经4h42℃热诱导后,在SDS-PAGE电泳上出现了一条新的蛋白带,Mr为33×103～35×103.结论BSP在大肠杆菌中得到了表达,其Mr为33×103～35×103,为进一步蛋白纯化及抗体制备奠定了基础.     

Hepatic transport of serum bilirubin,bromsulfophthalein, and indocyanine green in patients with congenital non-hemolytic hyperbilirubinemia and patients with constitutional indocyanine green excretory defect

We carried out a retrospective study of 71 patients with congenital non-hemolytic hyperbilirubinemia who had been treated at our institution over the 25 years from 1965 to 1990. Twenty patients had Gilbert's syndrome, 1 had Crigler-Najjar syndrome, 1 had new type unconjugated hyperbilirubinemia, 21 had Dubin-Johnson syndrome, and 28 had Rotor's syndrome. We also reviewed 20 patients with constitutional indocyanine green (ICG) excretory defect. The study focused on the hepatic transport of serum bilirubin, bromsulfophthalein (BSP), and ICG. In Dubin-Johnson syndrome, a defect appeared in late-stage transport, while uptake and storage capacity were normal. In Rotor's syndrome, defects were found in the early stage, and storage capacity was reduced, while excretion into bile was slightly suppressed. A secondary rise in serum ICG was seen in 5 of the 10 patients with Dubin-Johnson syndrome. The transport defect in Gilbert's syndrome was unclear. It could not be considered to be homogeneous, but it may exist at multiple sites, from the conjugation with serum proteins to excretion into bile. Following phenobarbital administration, the ICG secondary rise in the 5 patients with Dubin-Johnson syndrome disappeared, and ICG was rapidly cleared from blood. However, in patients with Dubin-Johnson syndrome, BSP clearance in serum did not show any change before and after phenobarbital administration. ICG excretion in patients with constitutional ICG excretory defect was due only to the impairment o ICG transport, and the defect was suggested to be hepatic uptake. These results indicate that studies of the hepatic transport of bilirubin, BSP, and ICG are useful for determining the etiological factors involved in congenital hyperbilirubinemia and constitutional ICG excretory defect.     

Promoter hypomethylation and increased maspin expression in preeclamptic placentas in a Chinese population

ObjectivePreeclampsia is thought to begin with shallow trophoblast invasion and inadequate spiral artery remodeling. Maspin, a tumor-suppressor gene, plays a regulatory role in trophoblast invasion and motility. The tissue-specific methylation of the maspin promoter can regulate maspin gene expression in various cancers. We sought to detect maspin gene expression and assess the degrees of methylation of maspin promoter regions in preeclamptic placentas in the Han Chinese population and to investigate the potential role of maspin in the pathophysiology of preeclampsia.MethodsWe conducted RT-PCR, immunohistochemistry and western blotting to characterize maspin gene expression and protein levels in the placentas from normal and preeclamptic pregnancies. Finally, using methylation-specific PCR and bisulfite sequencing PCR, we detected the degrees of methylation of the promoter regions of maspin in each of the two studied groups.ResultsMaspin expression was increased at the mRNA and protein levels in the preeclamptic placentas compared to the control group. Maspin immunohistochemical staining revealed positive staining in the syncytio-cytotrophoblast layers and more diffuse staining in the preeclamptic group. The mean methylation level of the analyzed promoter region was significantly hypomethylated in the preeclamptic placentas compared to the control placentas, pointing to a negative relationship between maspin promoter methylation and gene expression.DiscussionHypomethylation of the maspin promoter results in increased expression of maspin in preeclamptic placentas, which suggests a negative relationship between maspin methylation and maspin expression in this Han Chinese population. Thus, maspin is likely involved in the etiology of preeclampsia.     

5' CpG island methylation analysis identifies the MAGE-A1 and MAGE-A3 genes as potential markers of HCC

OBJECTIVES: The change in DNA methylation patterns can be used to distinguish between normal and cancer cells. The aim of the present study was to examine the 5' CpG island methylation patterns of the cancer-testis antigen (CT antigen) gene family, MAGE-As, in hepatocellular carcinoma (HCC), and to develop the DNA demethylation pattern as a novel tumor biomarker. METHODS: We used bisulfite-sequencing PCR (BSP) to map the methylation status of the CpG site among the promoter of the MAGE-A gene family in several HCC cell lines including Hep G2, BEL7402, BEL7404, and BEL7407, and normal peripheral blood white blood cells (WBCs). According to differences of the methylation pattern between HCC cell lines and the control, methylation-special PCRs (MSP) have been developed. The developed MSPs were used to detect the paraffin-embedded slices that were pathologically diagnosed as HCC, hepatocirrhosis, hepatitis, and healthy. RESULTS: We found that several CpG sites among the MAGE-A1 and MAGE-A3 promoters have different methylation patterns in the HCC cell lines as compared to those in normal WBCs. Two sets of MSP primers were designed to distinguish the HCC genomic DNA and normal control cell genomic DNA as novel tumor biomarkers, and the biomarkers were validated on the archived paraffin sections of liver primary tissue. In the detection of 34 HCCs and 17 tumor-free liver tissues, the clinical sensitivity and specificity were 91.2% and 100%, respectively. CONCLUSION: Detection of aberrant methylation patterns of MAGEs CpG islands using MSP may be useful for diagnosis of HCC.     

Characterisation of the constitutive over-expression of AJ18 in a novel rat stromal bone marrow cell line (D8-SBMC)

Objective

The elucidation of the molecular pathways involved in osteoblast proliferation and differentiation has been greatly enhanced by the availability of cell culture model systems. However, many of the current bone cell culture systems suffer from disadvantages such as the inability to generate mineralised bone-like nodules, a transformed genetic background, cell heterogeneity, and a relatively long time frame from cell seeding to mineralisation, often in the order of several weeks. Here we describe the establishment and characterisation of a novel bone cell line named D8-SBMC. As a first demonstration of their potential value, D8-SBMC was utilised to further support a role for AJ18 during osteogenesis.

Design

D8-SBMC was established from a single cell suspension of the previously characterised long term rat stromal bone marrow cells [Kotev-Emeth S, Pitaru S, Pri-Chen S, Savion N. Establishment of a rat long-term culture expressing the osteogenic phenotype: dependence on dexamethasone and FGF-2. Connect Tissue Res 2002;43(4):606-12; Pitaru S, Kotev-Emeth S, Noff D, Kaffuler S, Savion N. Effect of basic fibroblast growth factor on the growth and differentiation of adult stromal bone marrow cells: enhanced development of mineralized bone-like tissue in culture. J Bone Miner Res 1993;8(8):919-29]. AJ18 was constitutively and stably over-expressed in D8-SBMC and analysed.

Results

D8-SBMC possesses the ability to form robust mineralised bone-like nodules within 8 days proceeding cell confluency. Interestingly, a cement line-like matrix is also generated between the culture dish and a basal monolayer of cells. Constitutive and stable over-expression of AJ18 resulted in an increase in cell proliferation and mineralisation. Expression of bone marker genes, such as bone sialoprotein, osteopontin, osteocalcin, collage type 1, and osteonectin, was up-regulated by AJ18 over-expression.

Conclusion

A novel bone cell line, D8-SBMC, was established and characterised. D8-SBMC may be a valuable model system for biomineralisation studies. D8-SBMC was utilised to further understand the role of AJ18 in cell proliferation and differentiation during osteogenesis.     

Organic anion transporting polypeptides expressed in liver and brain mediate uptake of microcystin

Microcystins are toxins produced by freshwater cyanobacteria. They are cyclic heptapeptides that exhibit hepato- and neurotoxicity. However, the transport systems that mediate uptake of microcystins into hepatocytes and across the blood-brain barrier have not yet been identified. Using the Xenopus laevis oocyte expression system we tested whether members of the organic anion transporting polypeptide superfamily (rodent: Oatps; human: OATPs) are involved in transport of the most common microcystin variant microcystin-LR by measuring uptake of a radiolabeled derivative dihydromicrocystin-LR. Among the tested Oatps/OATPs, rat Oatp1b2, human OATP1B1, human OATP1B3, and human OATP1A2 transported microcystin-LR 2- to 5-fold above water-injected control oocytes. This microcystin-LR transport was inhibited by co-incubation with the known Oatp/OATP substrates taurocholate (TC) and bromosulfophthalein (BSP). Microcystin-LR transport mediated by the human OATPs was further characterized and showed saturability with increasing microcystin-LR concentrations. The apparent K(m) values amounted to 7 +/- 3 microM for OATP1B1, 9 +/- 3 microM for OATP1B3, and 20 +/- 8 microM for OATP1A2. No microcystin-LR transport was observed in oocytes expressing Oatp1a1, Oatp1a4, and OATP2B1. These results may explain some of the observed organ-specific toxicity of microcystin-LR. Oatp1b2, OATP1B1, and OATP1B3 are responsible for microcystin transport into hepatocytes, whereas OATP1A2 mediates microcystin-LR transport across the blood-brain barrier.     

Okadaic acid is taken-up into the cells mediated by human hepatocytes transporter OATP1B3

Okadaic acid is known as a diarrheal shellfish poison. It is thought that there is no specific target organ for okadaic acid after it has been absorbed into the body. However, the details of its pharmacokinetics are still unknown.In this study, we demonstrated that okadaic acid was more toxic to the hepatocyte-specific uptake transporter OATP1B1- or OATP1B3-expressing cells than control vector-transfected cells. In addition, PP2A activity, which is a target molecule of okadaic acid, was more potently inhibited by okadaic acid in OATP1B1- or OATP1B3-expressing cells compared with control vector-transfected cells. The cytotoxicity of okadaic acid in OATP1B1- or OATP1B3-expressing cells was attenuated by known substrates of OATP1B1- and OATP1B3, but not in control vector-transfected cells. Furthermore, after uptake inhibition study using OATP1B3-expressing cells, Dixon plot showed that okadaic acid inhibited the uptake of hepatotoxin microcystin-LR, which is a substrate for OATP1B1 and OATP1B3, in a competitive manner. These results strongly suggested that okadaic acid is a substrate for OATP1B3 and probably for OATP1B1, and could be involved in unknown caused liver failure and liver cancer. Since okadaic acid possesses cytotoxicity and cell proliferative activity by virtue of its known phosphatase inhibition activity.     

The excretory capacity of the isolated rat liver

Summary Excretory function of a perfused rat liver preparation has been quantified by determination of the BSP-transport maximum (BSP-Tm). An in situ liver perfusion system employing a semisynthetic perfusion medium containing Krebs-Ringer-bicarbonate solution, bovine erythrocytes and bovine albumin was used. Taurocholate was continuously infused throughout the perfusion to provide the liver with a physiologic load of bile salts.After 3 h of perfusion the BSP-Tm was 33.8±SD 4.7 nmoles/min/g liver. In spite of a 33% reduction of bile flow due to a decrease of the bile salt independent fraction, the BSP-Tm was not significantly different from that found in bile fistula rats of the same strain (36.5±SD 9.6 nmoles/min/g liver). It is concluded that the BSP-Tm of this perfused rat liver preparation, provided with a physiologic load of bile salts, may be maintained at in vivo values. This perfusion model may therefore be particularly useful for quantitative studies of the hepatic excretory processes.Supported by the Swiss National Foundation for Scientific Research