A prodrug strategy using ONYX-015-based replicating adenoviruses to deliver rabbit carboxylesterase to tumor cells for conversion of CPT-11 to SN-38

ONYX-015 has been used successfully in the clinic as a cancer therapeutic in combination with chemotherapy. The combination of ONYX-015 and chemotherapy appears to be more efficacious than either regimen alone. In this study, we try to enhance this combination by "arming" ONYX-015 with a therapeutic transgene, an approach more commonly used with nonreplicating viruses in the context of gene therapy. We chose the prodrug converting enzyme carboxylesterase (CE), which converts the camptothecin derivative CPT-11 (irinotecan) to the much more potent chemotherapeutic SN-38. The transgene was introduced into three distinct positions in the E3 region of the adenovirus genome to allow either early or late expression during the virus life cycle. We demonstrate that each of these ONYX-015-based adenoviruses expresses an active CE enzyme that can efficiently convert CPT-11 to SN-38. Furthermore, the cytotoxicity of CE-expressing viruses, but not control viruses, is enhanced significantly in the presence of the prodrug. Finally, we demonstrate that we can achieve transgene expression and activity in vivo in a human tumor xenograft model, and that treatment with a CE-expressing virus in combination with CPT-11 enhances survival of tumor-bearing mice. These results indicate that the addition of a prodrug converting enzyme may be a feasible approach to additionally enhance the efficacy of replicating adenoviruses as cancer therapeutics.     

Worsening of hypertension in a pregnant woman with renal arteriovenous malformation: a successful superselective embolization after delivery

A 30-year-old female presented with uncontrolled hypertension due to arteriovenous malformation in the upper third of the right kidney, which worsened during pregnancy. The arteriovenous malformation was detected by color-coded Doppler sonography, confirmed by angiography, and the fistula was sealed by superselective arterial embolization with metallic coils. Superselective embolization is the most effective and safe treatment for this rare and complex pathology.     

Effects of mechanical stress and high glucose on pericyte proliferation, apoptosis and contractile phenotype

Pericyte loss is an early step of diabetic retinopathy. High glucose induces apoptosis in retinal pericytes, but systemic and capillary hypertension are also believed to be important in the onset and progression of diabetic retinopathy. The haemodynamic insult of retinal capillary hypertension can be mimicked by exposing pericytes to mechanical stretch. We investigated the effect of stretch combined with high glucose on pericyte proliferation/apoptosis and morphology. Bovine retinal pericytes, cultured in either normal or high glucose concentrations in flexible-base plates, were exposed to mechanical stretch for 48/72 h. Cell replication was determined by both cell counting and DNA synthesis, apoptosis by ELISA, cell morphology and actin cytoskeleton distribution by immunofluorescence. Both reduction in cell proliferation and increase in apoptosis were confirmed in high glucose alone. When cells were subjected to stretch, proliferation was reduced and apoptosis increased in both normal and high glucose in comparison with unstretched controls. In both cases, a synergistic effect of hyperglycaemia combined with stretch was shown. Cell morphology showed modifications of cytoskeleton in all experimental conditions; in particular, cells subjected to stretch showed a clear elongation and translocation of actin fibres. In conclusion, our results show that stretch, alone or combined with high glucose, reduces cell proliferation, increases apoptosis and induces morphological changes in pericyte cytoskeleton. Further elucidations of the mechanisms on the basis of reduced proliferation of pericytes subjected to high glucose and stretch could help to clarify the effects of combined hyperglycaemia and hypertension in the pathogenesis of diabetic retinopathy.     

Parenteral morphine prescribing patterns among inpatients with pain from advanced cancer: a prospective survey of intravenous and subcutaneous use

Prescribing patterns for parenteral morphine for symptom control in advanced cancer were studied in 50 consecutive hospital admissions (27 men, 23 women, median age, 62 years). Patients were interviewed daily (median time, 9 days) concerning analgesia while they were receiving parenteral morphine. Five major inpatient prescribing patterns were identified: (1) intravenous to oral, (2) intravenous to subcutaneous, (3) intravenous only, (4) subcutaneous only, and (5) mixed. The intravenoustooral group had more stable pain control than the intravenous-to-subcutaneous group. Pain control was good in the mixed group, suggesting that flexibility in the route of administration contributes to better pain control. Patients with neuropathic pain required higher doses of morphine. These patterns of parenteral morphine application reflect the complexity of the challenge presented by the various cancer pain syndromes. Physicians should be knowledgeable about the appropriate and flexible use of different routes of administration for morphine and other opioids.     

Specific sensitivity of small cell lung cancer cell lines to the snake venom toxin taipoxin

Small cell lung cancer (SCLC) is a malignant disease, for which no satisfactory treatment is presently available and consequently, new specific therapeutic targets are in high demand.

A global gene expression analysis previously performed, identified the neuronal pentraxin receptor (NPR) as highly and relatively specifically expressed in SCLC, consistent with the neuroendocrine features of this cancer. Normally, NPR is exclusively expressed in neurons, where it associates with the homologous proteins neuronal pentraxins 1 and 2 (NP1 and NP2) in complexes capable of binding the snake venom neurotoxin taipoxin.

The purpose of the present study was to assess the toxic effect of taipoxin in SCLC-cell lines and to determine if toxicity correlates to NPR and NP1 and NP2 expression levels.

NPR was detected by Western blot analysis in all the tested SCLC and in control cell lines of different origin. The receptor co-purified with cell membrane in SCLC, indicating that NPR is surface associated. Microarray signals for NP1 and NP2 mRNA was detected in a subset of SCLC-cell lines and validated by Northern blot analysis. Furthermore, NP1 protein was detected by Western blot analysis in a few SCLC-cell lines, but not in the control cell lines. A number of SCLC-cell lines showed marked sensitivity to taipoxin (IC₅₀: 3–130 nM) at toxin concentrations leaving the control cell lines unaffected. The sensitivity to taipoxin did not correlate with the expression levels of NP1 protein and NP2-mRNA, suggesting that expression of these proteins may not be required for taipoxin induced toxicity in SCLC.

The demonstrated toxic effect of taipoxin in SCLC may prove to be of importance for designing novel specific treatment modalities for this disease.     

Primary and immortalised human pancreatic islet endothelial cells: phenotypic and immunological characterisation

Aims/hypothesis Studies on the biology of the microvascular endothelial cells (MECs) that surround and penetrate the pancreatic islets are hampered by difficulties in isolating and culturing large numbers of pure cells. We aimed to morphologically and functionally characterise primary MECs purified and cultured from human islets, and to establish a simian virus 40 (SV40)-immortalised cell line from these primary cultures. Materials and methods Human islet MECs were extracted and purified using anti-CD105 coated immunomagnetic beads, and endothelial markers and surface molecules analysed by flow cytometric analysis. An immortalised cell line was then established by using a chimeric adeno5/SV40 virus. Results Islet MECs expressed classic and specific endothelial markers, a high basal level of intercellular adhesion molecule-1, and low levels of E-selectin and TNF (previously known as TNF-α) inducible vascular cell adhesion molecule-1. IFNG (previously known as IFN-γ) induced expression of HLA class II molecules. The immortalised islet MECs expanded rapidly, exhibited increased DNA synthesis, and were passaged approximately 30 times, without signs of senescence. They retained the endothelial characteristics of the parental cells, and behaved as the primary cells in terms of TNF stimulation of expression of adhesion molecules and support of leucocyte adhesion and transmigration. Conclusions/interpretation The immortalised islet MECs that we have established could effectively represent a substitute for primary counterparts for in vitro studies on the role of the microvasculature in pathophysiological processes involved in type 1 and type 2 diabetes.     

Macrophage targeting with 99mTc-labelled J001 for scintigraphic assessment of experimental osteoarthritis in the rabbit

The potential of scintigraphy with technetium 99m-labelled J001 (99mTc- J001) to detect synovitis was studied in 15 rabbits with osteoarthritis (OA) of the right knee (section of cruciate ligaments), in five sham- operated rabbits and in four non-operated rabbits. J001 is a non- pyrogenic, acylated poly (1,3) galactoside isolated from the membrane of a non-pathogenic strain of Klebsiella pneumoniae which is able to bind selectively to macrophages via the binding to CD11b and CD14 molecules. The results of 99mTc-J001 scintigraphy were compared with those of scintigraphy with 99mTc-labelled methylene diphosphonate (99mTc-MDP) and GC-APG (a derivative of J001 unable to bind macrophages in vitro). The mean scintigraphic ratios (diseased healthy knee) of 99mTc-J001 were significantly higher in OA rabbits than in sham- and non-operated rabbits, from as early as day 18 until day 90. 99mTc-J001 scintigraphy demonstrated earlier increased uptake than 99mTc-MDP scintigraphy. The mean scintigraphic ratios of 99mTc-J001 were significantly higher than those of 99mTc-GC-APG (which remained normal) in OA rabbits. The normal scintigraphic ratios of 99mTc-J001 in sham- operated and non-operated rabbits, as well as of 99mTc-GC-APG in OA rabbits, suggested that the increased uptake demonstrated with 99mTc- J001 in OA rabbits, as early as day 18 corresponded to imaging of synovitis via elective macrophage targeting. These results showed that 99mTc-J001 scintigraphy should be a specific method of detecting synovitis in OA.