AAV-mediated delivery of interferon-β for the treatment of retinoblastoma in preclinical models

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Background: Interferon-β has anti-tumor properties against a variety of malignancies through direct cytotoxicity as well as immunological effects. In order to circumvent limitations of IFN-β therapy, we have developed an adeno-associated viral gene therapy approach to deliver IFN-β directly to tumors. In this study, we tested the efficacy of AAV mediated delivery of IFN-β in preclinical retinoblastoma models. Retinoblastoma is an ideal candidate for gene-therapy based anti-cancer treatments because viral infection and IFN-β delivery can be contained within the ocular environment thereby minimizing systemic toxicity. Methods: Retinoblastoma cell lines Weri and Y79 were treated in vitro with recombinant human Interferon-β and then subjected to Viacount assays, Nexin apoptosis assays, FACS cell cycle analysis, and immunolabeling for proliferation (BrdU) and apoptosis (caspase and TUNEL). An orthotopic Xenograft retinoblastoma rat model with luciferase reporter were established and treated with single subconjunctival injection of AAV-IFN-β gene therapy. Xenogen in vivo imaging was used to follow tumor volume. Blood and tissue samples (ELISA) were obtained to determine IFN-β levels. Results: Weri and Y79 cells showed maximum reduction in viability at 500 IU/ml and 2500 IU/ml respectively. Weri response was found to be cell death by Caspase and TUNEL assay. Y79 response was found to be due to suppression of proliferation as measured by BrdU incorporation and cell cycle analysis. In the retinoblastoma xenograft model there was no increase in tumor volume by serial in vivo imaging compared to control animals. Stable levels of IFN-β were maintained at 20 ng/ml >6weeks following injection. Plasma levels were undetectable 42 days following treatment. Conclusions: Retinoblastoma cell lines exhibit pleiotropic responses to IFN-β consistent with previous studies. Intravitreal injection of AAV-IFN-β resulted in efficient retinal infection and sustained IFN-β production. Viral spread outside of the eye was not detected. Using our retinoblastoma xenograft model we found that intravitreal injection of AAV-IFN-β had a potent anti-tumor effect in vivo. These data suggest that AAV mediated delivery of IFN-β may provide a complementary approach to systemic chemotherapy.

No significant financial relationships to disclose.

The inhibitor of apoptosis protein survivin is associated with high-risk behavior of neuroblastoma

BACKGROUND/PURPOSE

Apoptotic factors inducing or preventing cell death may intrinsically govern the behavior of some tumors. Survivin is a recently described member of the inhibitor of apoptosis protein (IAP) family, that is expressed in a cell cycle-dependent manner and is found in tumors of unfavorable histology. This study examines the presence of several apoptotic factors, including survivin, in neuroblastoma (NB) tumors. Clues to survivin's function in NB are provided by examining its association with behavior and cell dynamics in tumors and cell lines.

METHODS

Expression of a panel of apoptosis factors were quantified in 15 NB and related tumors before chemotherapy and in 3 NB cell lines (NB7, NB10, and NB16). Survivin and other apoptotic factors, as well N-myc amplification in primary tumors was correlated with recurrent disease and outcome. Proliferation rate, apoptosis assays, cell cycle analysis, and drug- or immune-mediated cell death were assessed in cell lines and evaluated in the context of differential survivin and apoptosis gene expression.

RESULTS

All 7 tumors that went on to recur expressed survivin, whereas expression was absent in all 8 tumors that went into remission. N-myc was amplified in 4 (57.1%) of the 7 recurrent tumors. Of the 8 tumors that were cured, Fas was expressed in 3 (38%), TRAIL-R1 in 6 (75%) and tumor necrosis factor (TNF)-R1 in 8 (100%), whereas these pro-apoptotic receptors were present in only 1 (14%), 1 (14%), and 4 (57%) of the 7 tumors that went on to recur, respectively. Of the 3 cell lines, NB10 expressed the least survivin, displayed the lowest proliferation index, and had the fewest number of cells in the G2/M (mitotic) phase of the cell cycle. Furthermore, NB10 also was most sensitive to TNF-related apoptosis-inducing ligand (TRAIL) or etoposide-induced cell death.

CONCLUSIONS

In primary NB tumors, survivin expression was associated with tumors of high risk and unfavorable prognosis, whereas pro-apoptotic receptor expression was more abundant in tumors of favorable prognosis. In this small series, survivin expression appeared to be more predictive of recurrent disease than N-myc amplification. In cell lines, survivin expression was cell cycle dependent, and its expression was associated with greater proliferation rates and greater resistance to drug- or immune-mediated cell death. Survivin expression may become a useful prognostic marker in NB and could be a potential target for the treatment of this tumor. J Pediatr Surg 36:1785-1791.

Factors influencing in vivo transduction by recombinant adeno-associated viral vectors expressing the human factor IX cDNA

Long-term expression of coagulation factor IX (FIX) has been observed in murine and canine models following administration of recombinant adeno-associated viral (rAAV) vectors into either the portal vein or muscle. These studies were designed to evaluate factors that influence rAAV-mediated FIX expression. Stable and persistent human FIX (hFIX) expression (> 22 weeks) was observed from 4 vectors after injection into the portal circulation of immunodeficient mice. The level of expression was dependent on promoter with the highest expression, 10% of physiologic levels, observed with a vector containing the cytomegalovirus (CMV) enhancer/beta-actin promoter complex (CAGG). The kinetics of expression after injection of vector particles into muscle, tail vein, or portal vein were similar with hFIX detectable at 2 weeks and reaching a plateau by 8 weeks. For a given dose, intraportal administration of rAAV CAGG-FIX resulted in a 1.5-fold or 4-fold higher level of hFIX compared to tail vein or intramuscular injections, respectively. Polymerase chain reaction analysis demonstrated predominant localization of the rAAV FIX genome in liver and spleen after tail vein injection with a higher proportion in liver after portal vein injection. Therapeutic levels of hFIX were detected in the majority of immunocompetent mice (21 of 22) following intravenous administration of rAAV vector without the development of anti-hFIX antibodies, but hFIX was not detected in 14 immunocompetent mice following intramuscular administration, irrespective of strain. Instead, neutralizing anti-hFIX antibodies were detected in all the mice. These observations may have important implications for hemophilia B gene therapy with rAAV vectors.

Accuracy of percutaneous lung biopsy for invasive pulmonary aspergillosis

BACKGROUND

Invasive pulmonary aspergillosis is fulminant and often fatal in immunosuppressed patients. Percutaneous biopsy may select patients who could benefit from surgical resection.

OBJECTIVE

We sought to determine the accuracy of percutaneous biopsy for pediatric invasive pulmonary aspergillosis.

MATERIALS AND METHODS

We retrospectively reviewed 28 imaging-guided percutaneous biopsies of the lungs of 24 children with suspected pulmonary aspergillosis. Twenty-two were being treated for malignancy and two for congenital immunodeficiency; 15 had received bone-marrow transplants. The accuracy of the percutaneous lung biopsy was determined by subsequent surgical resection, autopsy, or clinical course.

RESULTS

Histopathological studies showed ten biopsy specimens with septate hyphae, indicating a mold, and seven with Aspergillus flavus colonies in culture. The remaining 18 biopsies revealed no fungi. No patient had progressive aspergillosis after negative biopsy. Invasive pulmonary mold was detected by percutaneous biopsy with 100% (10/10) sensitivity and 100% (18/18) specificity. Percutaneous biopsy results influenced the surgical decision in 86% (24 of 28) of the cases. Bleeding complicated the biopsy in 46% (13/28) and hastened one death.

CONCLUSION

Percutaneous biopsy of the lung is an accurate technique for the diagnosis of invasive pulmonary aspergillosis and correctly determines which immunosuppressed pediatric patients would benefit from therapeutic pulmonary resection.

Hepatic iron concentration: noninvasive estimation by means of MR imaging techniques

PURPOSE

To identify a magnetic resonance (MR) imaging method sufficiently sensitive and specific in the estimation of hepatic iron content to obviate liver biopsy.

MATERIALS AND METHODS

Thirty-eight patients underwent percutaneous needle biopsy of the liver with chemical measurement of the hepatic iron concentration and hepatic MR imaging with several spin-echo and gradient-recalled-echo (GRE) techniques. Correlations between MR imaging parameters and the hepatic iron concentration were determined.

RESULTS

Inverse curvilinear relationships were noted between several MR parameters and hepatic iron concentrations. GRE sequences with short repetition and echo times were more accurate and precise than spin-echo sequences for the estimation of hepatic iron concentration. A GRE sequence with a repetition time of 18 msec, an echo time of 5 msec, and a flip angle of 10 degrees showed close correlation between the hepatic iron concentration and the natural logarithm of the ratio of the signal intensity of liver to the SD of background noise (r = -0.94) and low coefficient of variation (12%).

CONCLUSION

MR imaging with these parameters is a rapid, noninvasive, and accurate modality for estimation of hepatic iron concentration; it is sufficiently accurate and precise to obviate liver biopsy for the purpose of measuring hepatic iron concentration.

Control of monocyte influx in glomerulonephritis in transplanted kidneys in the rat

Induction of anti-Thy-1 nephritis in different strains of inbred rats results in phenotypically different types of renal diseases. In Wistar and Lewis (LEW) rats, a transient influx of ED1+ macrophages occurs 24 hours after injection of anti-Thy-1 antibodies, whereas this does not occur in F344 rats. The present experiments were designed to investigate the role of the kidney in the regulation of the monocyte influx in this model. To dissociate the role of the immune system from local intrarenal factors in the control of monocyte influx, anti-Thy-1 nephritis was induced in LEW rats with an F344 kidney transplant and in F344 rats with a LEW kidney allograft. Acute rejection episodes were prevented by treatment with an anti-CD4 monoclonal antibody. Control rats received a syngeneic kidney graft. Monocyte influx after injection of anti-Thy-1 antibodies was found in the glomeruli of both LEW and F344 kidneys removed from LEW recipients, whereas there was no demonstrable monocyte influx after infusion of anti-Thy-1 antibodies in either LEW or F344 kidneys removed from F344 recipients. Monocyte infiltration correlated with the subsequent expansion of the mesangial extracellular matrix. The inability to attract monocytes was not due to the lack of glomerular expression of chemokines, because F344 and LEW glomeruli demonstrated a similar expression of monocyte chemoattractant protein-1 (MCP-1). Differences in the ability to activate the complement system were excluded. We conclude that the immune system controls the glomerular influx of monocytes and that the reaction of the mesangial cells is probably controlled by combinations of cytokines produced during the inflammatory process.

Neonatal sternal cleft associated with an extrathoracic cystic mass

This report describes an unusual case of cystic exophytic tumor associated with a complete sternal cleft. The tumor masked the presence of sternal cleft on prenatal ultrasound scan.

Antihypertensive drug treatment in chronic renal allograft rejection in the rat. Effect on structure and function

To gain insight into the contribution of immunologic and hemodynamic factors in the progressive demise of structure and function in chronic renal allograft dysfunction, we studied the histological changes, the immunostainable glomerular anionic sites, and glomerular capillary hydrostatic pressures of rat renal allografts with chronic rejection. Recipient animals were left untreated, received 8 weeks of treatment with the immunosuppressive drug cyclosporine, or received antihypertensive drugs consisting of the combination of reserpine, hydralazine and hydrochlorothiazide, the angiotensin-converting enzyme inhibitor cilazapril, or the angiotensin II receptor blocker L-158,809. Grafts in untreated recipients developed chronic interstitial inflammation, as well as vascular and glomerular lesions consistent with chronic rejection. These lesions were associated with immunohistochemical loss of the negatively charged heparan sulfate proteoglycan side chain. All treatment regimens decreased the systemic and glomerular capillary pressures and were associated with no loss of function, decreased proteinuria, and a tendency to improved graft function. Cyclosporine prevented all histological manifestations of rejection, and antihypertensive drugs decreased the extent of glomerular mesangiolysis and glomerulosclerosis; L-158,809 and cilazapril also inhibited graft atherosclerosis and tubular atrophy. We conclude that chronic rejection is primarily an immune-mediated process, but hemodynamic and angiotensin II-mediated effects may play a pivotal role in the expression of immune-mediated lesions.

Growth factor transcripts in rat renal transplants

Locally produced cytokines and growth factors may mediate tissue remodelling processes, as observed in renal transplants exposed to ischemia or acute rejection episodes. The present study was designed to investigate mRNA transcript levels of platelet-derived growth factor (PDGF)-receptor beta, PDGF-A, PDGF-B, fibroblast growth factor-1, and transforming growth factor beta 1 in normal rat kidneys, in kidneys following contralateral nephrectomy and in renal transplants with acute or chronic rejection. Platelet-derived growth factor-receptor beta mRNA levels increased significantly in syngeneic and allogeneic transplants in the first week after transplantation and in allogeneic transplants with chronic rejection. Immunohistochemistry showed induction of PDGF-receptor beta protein expression on vascular wall cells in such grafts. Platelet-derived growth factor-A chain mRNA levels increased in day 3 allografts and in syngeneic LEW grafts, while PDGF-B chain mRNA levels showed no significant changes with transplantation. Fibroblast growth factor-1 mRNA levels were detectable in normal kidneys, tended to decrease with acute rejection, and increased significantly in chronic rejection. Transforming growth factor-beta 1 transcripts increased in acute and chronic rejection; immunohistochemistry showed predominantly glomerular localization of the transforming growth factor-beta 1 protein. We conclude that transplantation and rejection are associated with changes in the intragraft mRNA levels for several growth factors; chronic rejection is characterized by an increase in fibroblast growth factor-1 and transforming growth factor-beta 1 transcript levels.

Anti-integrin (LFA-1, VLA-4, and Mac-1) antibody treatment and acute cardiac graft rejection in the rat

Cell adhesion molecules mediate interactions with other cells and extracellular matrix, control cell infiltration in sites of inflammation, and regulate cell activation. Previous studies have shown that treatment of rat cardiac transplant recipients with a combination of antibodies against the T-cell integrins LFA-1 and VLA-4 gave a modest prolongation of graft survival. Current experiments were designed to examine the effect of blocking Mac-1, an important monocyte adhesion receptor and mediator of monocyte migration, together with anti-LFA-1 and anti-VLA-4 antibodies on cardiac graft survival and on the graft rejection pattern. The anti-Mac-1, CD11b-specific antibody OX-42 did not affect graft survival time although it did decrease the graft infiltration by rounded, ED-2-positive macrophages.

Orthotopic liver transplantation for inflammatory myofibroblastic tumor of the liver hilum

Inflammatory myofibroblastic tumor is a rare gastrointestinal neoplasm. The authors report the case of a 5-year-old girl who initially presented with gastric outlet obstruction secondary to an inflammatory myofibroblastic tumor along the lesser gastric curvature. A subtotal gastrectomy and wedge resection of a left hepatic lobe nodule were performed. Obstructive jaundice developed one month postoperatively. Computerized tomography, percutaneous transhepatic cholangiography, and selective celiac and mesenteric arteriography showed a mass that involved the left hepatic lobe, with concomitant high-grade biliary obstruction and portal venous encasement. Percutaneous biliary drainage was performed. During laparotomy, the tumor was found to be unresectable, and the patient was referred to the Liver Transplant Service at The Children's Hospital of Philadelphia. A total hepatectomy with temporary portocaval shunt was performed, leaving the inferior vena cava in situ. At the back table, an ex vivo left trisegmentectomy was performed, followed by reimplantation of the posterior segment of the right hepatic lobe. The reimplanted liver segment functioned poorly, and completion hepatectomy with portocaval shunt was performed 24 hours postoperatively, because of severe coagulopathy, intraabdominal bleeding, and hemodynamic instability. The patient's condition stabilized, and she was listed for urgent liver transplantation. The anhepatic state was managed with intermittent plasmapheresis. She had transplantation 72 hours later, and was discharged from the hospital 3 weeks postoperatively after an uneventful recovery. She remains disease-free and has normal liver function 8 months after transplantation.

Successful management of intracardiac extension of tumor thrombus in a patient with advanced nonseminomatous germ cell testicular cancer

A young patient with testicular germ cell tumor presenting with inferior vena cava thrombus extending into the right heart with free-floating thrombus in the right ventricle and a simultaneous epidural spinal cord compression is presented. Due to the perceived high risk of embolization and the urgent need to begin systemic chemotherapy, he was managed with tumor thrombectomy utilizing cardiopulmonary bypass and hypothermic circulatory arrest followed shortly thereafter by systemic chemotherapy. There were no perioperative complications, and he is alive and without recurrence 24 months following four cycles of systemic chemotherapy.