Modulation of tissue factor and thrombomodulin expression in human aortic endothelial cells incubated with high glucose.

Diabetes is often associated with atherothrombosis. It is unknown whether high glucose can modulate the expression of tissue factor (TF) and thrombomodulin (TM) in human aortic endothelial cells (HAECs). HAECs were treated with a lower-degree high glucose condition (LG, 11.2 mM) for 8 days and a higher-degree high glucose condition (HG, 30 mM) for 4-6 h. Methoxyphenyl tetrazolium inner salt assay, real-time polymerase chain reaction, western blot, and TF activity assay were performed. In HAECs, both LG and HG conditions were nontoxic. LG caused a 74 ± 20% decrease (P = 0.273) and HG caused a 57 ± 5% decrease in TF mRNA expression (P = 0.001). LG caused a 53 ± 13% decrease (P = 0.036) and HG caused a 75 ± 10% decrease in TF protein expression (P = 0.096). TF activity was not significantly changed by LG (127 ± 13%, P = 0.40) or HG treatments (120 ± 42%, P = 0.70). In contrast, LG caused a 153 ± 16% increase (P = 0.03) and HG caused a 211 ± 20% increase in TM mRNA expression (P = 0.005). LG caused a 131 ± 31% increase (P = 0.35) and HG caused a 140 ± 9% increase in TM protein expression (P = 0.006). Different high glucose conditions do not provide the sufficient stress required to induce TF expression in HAECs. In contrast, high glucose conditions can induce TM expression in HAECs.

Study of [18F]FLT and [123I]IaraU for cellular imaging in HSV1 tk-transfected murine fibrosarcoma cells: evaluation of the tracer uptake using 5-fluoro, 5-iodo and 5-iodovinyl arabinosyl uridines as competitive probes.

As one of the most intensively studied probes for imaging of the cellular proliferation, [(18)F]FLT was investigated whether the targeting specificity of thymidine kinase 1 (TK1) dependency could be enhanced through a synergistic effect mediated by herpes simplex type 1 virus (HSV1) tk gene in terms of the TK1 or TK2 expression. 5-[(123)I]Iodo arabinosyl uridine ([(123)I]IaraU) was prepared in a radiochemical yield of 8% and specific activity of 21 GBq/µmol, respectively. Inhibition of the cellular uptake of these two tracers was compared by using the arabinosyl uridine analogs such as 5-iodo, 5-fluoro and 5-(E)-iodovinyl arabinosyl uridine along with 2'-fluoro-5-iodo arabinosyl uridine (FIAU). Due to potential instability of the iodo group, accumulation index of 1.6 for [(123)I]IaraU by HSV1-TK vs. control cells could virtually be achieved at 1.5 h, but dropped to 0.2 compared to 2.0 for [(18)F]FLT at 5 h. The results from competitive inhibition by these nucleosides against the accumulation of [(18)F]FLT implied that FLT exerted a mixed TK1- and TK2-dependent inhibition with HSV1-tk gene transfection because of the shifting of thymidine kinase status. Taken together, the combination of [(18)F]FLT and HSV1-TK provides a synergistic imaging potency.

The transcriptional activity of HERV-I LTR is negatively regulated by its cis-elements and wild type p53 tumor suppressor protein.

Human endogenous retroviruses (HERVs), abundantly inter-dispersed in the genome, carry long terminal repeats (LTRs) that may potentially retro-transpose to new genomic sites and deregulate the neighboring cellular genes. However, normally HERVs are either structurally defective or inactive due possibly to stringent negative control mechanisms. To study the possible negative regulation of HERV, we isolated the LTR of RTVL-Ia and constructed site-specific mutations for analysis of the promoter and enhancer functions by using chloramphenicol acetyl transferase (CAT) reporter assay. Our results showed that in most transfected human cells the LTR-mediated CAT expression was negligible unless a sequence segment at the AGTAAA polyadenylation site was deleted. In addition, we have found that the wild type p53 may inhibit whereas a p53 mutant (V143A) stimulate the transcriptional activity of HERV-I LTR. Our results imply that HERV-I LTR, while under negative control by its LTR cis-elements and by wild type p53, may become active upon p53 mutation.

Serial in vivo imaging of the lung metastases model and gene therapy using HSV1-tk and ganciclovir.

UNLABELLED: Noninvasive imaging in lung metastatic tumor models is used infrequently because of technical limitations in detecting metastases. We have previously used 2'-fluoro-2'-deoxy-5-iodo-1-beta-d-arabinofuranosyluracil labeled with (131)I ((131)I-FIAU) and demonstrated the applicability of noninvasive imaging for monitoring cancer gene therapy in an experimental animal model of herpes simplex virus type 1 thymidine kinase (HSV1-tk)-expressing tumor xenografts. We have now used the same animal model to effectively and noninvasively monitor the location, magnitude, and duration of therapeutic gene expression over time for the lung metastases model. METHODS: To improve the detectability of lung metastases, an experimental blood-borne lung metastases model in mice was established using intravenously administered HSV1-tk-expressing NG4TL4 fibrosarcoma cells (NG4TL4-TK) and simulated the clinical application of HSV1-tk plus ganciclovir (GCV) prodrug activation gene therapy. The efficacy of noninvasively monitoring the sites of development of lung metastatic lesions and their GCV-induced regression were assessed by SPECT with (131)I-FIAU. RESULTS: The results of this study showed that the lung metastases model of NG4TL4-TK cells could be successfully detected as early as 24 h after intravenous injection of tumor cells radiolabeled with (131)I-FIAU and also subsequently detected by extended monitoring with the intravenous injection of (131)I-FIAU on day 10. In mice treated with GCV, gamma-camera imaging demonstrated a significant growth inhibition of NG4TL4-TK cells of primary tumors and lung metastases on day 7 after initiating treatment. CONCLUSION: We conclude that this in vivo imaging approach will be useful for future studies of the lung metastases model and for the assessment of novel anticancer and antimetastatic therapies.

Tissue engineered cartilage using human articular chondrocytes immortalized by HPV-16 E6 and E7 genes.

Chondrocytes are useful as a cell culture system for studying arthritic degeneration in tissue engineered cartilage. However, primary chondrocytes have short in vitro lifespan and rapid shift of collagen phenotype. In this study, we used a high dosage of retroviral vector LXSN16E6E7 to transduce human primary chondrocytes and obtained an actively proliferating cell line, designated hPi, which expresses HPV-16 E6/E7 mRNA in early passages. Parental primary chondrocytes cease to grow after five passages, whereas hPi could be propagated beyond 100 passages without requiring additional cell elements in defined medium. After 48 passages, hPi can also give many profiles similar to those of parental primary chondrocyte, including type II collagen in mRNA and protein level, aggrecan in mRNA level, lacunae in type I collagen matrices, and morphology with GAG-specific Alcian blue staining. hPi has shown neoplastic transformation, as examined by NOD-SCID mice tumorigenicity assays for 3 months. Our results indicated that human primary chondrocytes could be immortalized by transduction with HPV-16 E6/E7, preserving stable cartilage-specific differentiation markers. The established chondrocyte cell line could provide a novel model to engineer cartilage in vitro and in vivo for cartilage repair research and clinical application.

Mesenchymal stem cell targeting of microscopic tumors and tumor stroma development monitored by noninvasive in vivo positron emission tomography imaging.

The aim of this study was to assess the efficacy human mesenchymal stem cells (hMSC) for targeting microscopic tumors and suicide gene or cytokine gene therapy. Immunodeficient mice were transplanted s.c. with human colon cancer cells of HT-29 Inv2 or CCS line, and 3 to 4 days later, i.v. with "tracer" hMSCs expressing herpes simplex virus type 1 thymidine kinase (HSV1-TK) and enhanced green fluorescent protein (EGFP) reporter genes. Subsequently, these tumors were examined for specificity and magnitude of HSV1-TK(+), EGFP(+) stem cell engraftment and proliferation in tumor stroma by in vivo positron emission tomography (PET) with (18)F-labeled 9-(4-fluoro-3-hydroxymethylbutyl)-guanine ([(18)F]-FHBG). In vivo PET images of tumors growing for 4 weeks showed the presence of HSV1-TK(+) tumor stroma with an average of 0.36 +/- 0.24% ID/g [(18)F]-FHBG accumulation. In vivo imaging results were validated by in situ correlative histochemical, immunofluorescent, and cytometric analyses, which revealed EGFP expression in vWF(+) and CD31(+) endothelial cells of capillaries and larger blood vessels, in germinal layer of dermis and hair follicles proximal to the s.c. tumor site. These differentiated HSV1-TK(+), GFP(+) endothelial cells had limited proliferative capacity and a short life span of <2 weeks in tumor fragments transplanted into secondary hosts. We conclude that hMSCs can target microscopic tumors, subsequently proliferate and differentiate, and contribute to formation of a significant portion of tumor stroma. PET imaging should facilitate clinical translation of stem cell-based anticancer gene therapeutic approaches by providing the means for in vivo noninvasive whole-body monitoring of trafficking, tumor targeting, and proliferation of HSV1-tk-expressing "tracer" hMSCs in tumor stroma.

IFN-beta induces caspase-mediated apoptosis by disrupting mitochondria in human advanced stage colon cancer cell lines.

Various human colon cancer cell lines tested in vitro differed significantly in susceptibility to growth inhibition of recombinant human interferon-beta (rHuIFN-beta). Two p53-mutant lines, COH and CC-M2, derived from high-grade colon adenocarcinoma, showed signs of apoptosis after treatment with 250 IU/ml of HuIFN- beta in the culture medium. The similarly p53-mutated HT-29 line from a grade I adenocarcinoma showed no apoptosis, however, and only cell cycle G1/G0 or S phase retardation with 1000 IU/ml HuIFN-beta. After HuIFN-beta exposure, COH and CC-M2 cells showed increased levels of Fas and FasL proteins, alteration of mitochondrial membrane potential, and activation of caspase-9, caspase-8, and caspase-3 in a time-dependent manner. Treatment of COH and CC-M2 cells with anti-FasL antibodies or rFas/Fc fusion protein, however, could not prevent the apoptosis induced by HuIFN-beta. In contrast, cell-permeable specific inhibitors of the three caspases could inhibit the DNA fragmentation and cell death but not the mitochondrial membrane potential changes. Treatment with mitochondria-stabilizing reagents could significantly abrogate the apoptosis and caspase activation induced by HuIFN-beta. These results suggest that in COH and CC-M2 colon cancer cell lines, HuIFN-beta induces apoptosis mainly through mitochondrial membrane alteration and subsequent activation of the caspase cascade pathway, but not by the Fas/FasL interaction or the p53-dependent apoptotic mechanism.

Immortalization without neoplastic transformation of human mesenchymal stem cells by transduction with HPV16 E6/E7 genes.

hMSCs derived from bone marrow are useful as a species-specific cell culture system for studying cell lineage differentiation and tissue remodeling. However, hMSCs usually have a short in vitro life span due to replicative senescence. We therefore used a high dose of retroviral vector LXSN-16E6E7 to transduce hMSCs of an aging donor and obtained an actively proliferating cell line, designated KP-hMSCs, which expressed HPV16 E6/E7 mRNA. Whereas parental hMSCs ceased to grow after 30 PDs, KP-hMSCs could be propagated beyond 100 PDs. With culture procedures to avoid selection pressure and crowded cell growth, KP-hMSCs showed no signs of neoplastic transformation as examined by soft-agar anchorage-independent growth and NOD-SCID mouse tumorigenicity assays. KP-hMSCs gave similar cytofluorimetric profiles of 31 CD markers to those of the parental primary hMSCs, except with some morphologic changes and expansion of an originally very minor CD34(dim)CD38(+)CD50+ cell population. Upon exposure to specific stimulating conditions in vitro, KP-hMSCs could respond and differentiate along the mesenchymal (bone, fat and cartilage) and nonmesenchymal (neuron) cell lineages. Our results indicated that hMSCs could be immortalized by transduction with HPV16 E6/E7, maintained without neoplastic transformation by careful culture procedures and thus useful for stem cell research and clinical application.

Non-invasive in vivo imaging with radiolabelled FIAU for monitoring cancer gene therapy using herpes simplex virus type 1 thymidine kinase and ganciclovir.

An experimental cancer gene therapy model was employed to develop a non-invasive imaging procedure using radiolabelled 2'-fluoro-2'-deoxy-5-iodo-1-beta- d-arabinofuranosyluracil (FIAU) as an enzyme substrate for monitoring retroviral vector-mediated herpes simplex virus type 1 thymidine kinase gene ( HSV1-tk) transgene expression. Iodine-131 labelled FIAU was prepared by a no-carrier-added (n.c.a.) synthesis process and lyophilised to give "hot kits". The labelling yield was over 95%, with a radiochemical purity of more than 98%. The stability of [(131)I]FIAU in the form of lyophilised powder (the hot kit) was much better than that in the normal saline solution. The shelf life of the final [(131)I]FIAU hot kit product is as long as 4 weeks. Cellular uptake of [(131)I]FIAU after different periods of storage was investigated in vitro with HSV1-tk-retroviral vector transduced NG4TL4-STK and parental non-transduced NG4TL4 murine sarcoma cell lines over an 8-h incubation period. The NG4TL4-STK cells accumulated more radioactivity than NG4TL4 cells in all conditions, and accumulation increased with time up to 8 h. The kinetic profile of the cellular uptake of n.c.a. [(131)I]FIAU formulated from the lyophilised hot kit or from the stock solution was qualitatively similar. For animal model cancer gene therapy studies, FVB/N mice were inoculated subcutaneously with the HSV1-tk(+) and tk(-) sarcoma cells into the flank to produce tumours. Biodistribution studies showed that tumour/blood ratios were 2, 3.5, 8.2 and 386.8 at 1, 4, 8 and 24 h post injection, respectively, for the HSV1-tk(+) tumours, and 0.5, 0.5, 0.7 and 5.4, respectively, for the HSV1-tk(-) tumours. Radiotracer clearance from blood was completed in 24 h and was bi-exponential. A significant difference in radioactivity accumulation was revealed among the HSV1-tk(+) tumours, the tk(-) tumours and other tissues. At 24 h p.i., higher activity retention was observed in HSV1-tk(+) tumours (9.67%+/-3.89%ID/g) than in HSV1-tk(-) tumours (0.48%+/-0.19%ID/g). After seven consecutive daily treatments with the prodrug ganciclovir, planar gamma camera imaging showed HSV1-tk(+) tumour regression at day 4, and complete tumour regression at day 7. These results clearly demonstrate that the simplified n.c.a. synthesis process developed in this study is reliable and that the [(131)I]FIAU product is useful for in vivo monitoring of HSV1-tk gene transfer, expression and gene therapy.

Colon cancer cells with high invasive potential are susceptible to induction of apoptosis by a selective COX-2 inhibitor.

Cyclooxygenase-2 (COX-2) expression has been shown to correlate with the invasiveness of colon cancer cells. To further investigate this positive correlation and its possible therapeutic implications, a selective COX-2 inhibitor, etodolac, was tested on three variants of HT-29 colon cancer cell lines, HT-29/Inv1, HT-29/Inv2 and HT-29/Inv3, with graded increases of in vitro Matrigel invasive potential and COX-2 expression levels. HT-29 variants with higher invasive potential were found to be more sensitive to etodolac by in vitro growth inhibition assays, the estimated LD(50) being 0.5 mM for highly invasive HT-29/Inv2 and HT-29/Inv3 cells, 0.6 mM for slightly less invasive HT-29/Inv1, and 1.8 mM for the parental HT-29. Treatment of the highly invasive HT-29/Inv2 and Inv3 variants with as little as 0.1 mM etodolac in the growth medium produced signs of apoptosis, as detected by DNA fragmentation and TUNEL (terminal deoxynucleotidyl transferase dUTP-biotin nick end labeling) assay. In vivo experiments in SCID mice showed that etolodac inhibited the growth of subcutaneous tumors induced by HT-29/Inv3 cells significantly more than those by the parental HT-29 cells. These results suggest that COX-2 inhibitors have a potential role in prevention of tumor invasion in colon cancer patients.