Richard L. Hurwitz

Hormonal therapy of cryptorchidism. A randomized, double-blind study comparing human chorionic gonadotropin and gonadotropin-releasing hormone

Abstract We conducted a randomized, double-blind study comparing intranasal gonadotropin-releasing hormone (1.2 mg per day for 28 days) with parenteral human chorionic gonadotropin (3300 IU per week for four weeks) in the treatment of cryptorchidism in 33 boys one to five years old (29 with unilateral and 4 with bilateral cryptorchidism). Testicular descent into the scrotum occurred in 3 of the 16 patients (19 percent) treated with gonadotropin-releasing hormone and in 1 of the 17 (6 percent) treated with human chorionic gonadotropin (P = 0.23). The mean luteinizing hormone and testosterone levels were similar in both groups before treatment. During treatment, the testosterone levels were significantly increased in both groups, but higher levels occurred in the group treated with human chorionic gonadotropin (P<0.05). In a parallel (but uncontrolled) study of five boys with retractile testes (defined as a nonscrotal testis that could be manipulated into the bottom of the scrotum) who were originally exclu...

Response of retinoblastoma with vitreous tumor seeding to adenovirus-mediated delivery of thymidine kinase followed by ganciclovir

PURPOSE To evaluate the feasibility and safety of adenovirus-mediated gene therapy as a treatment for tumor seeds in the vitreous of children with retinoblastoma. PATIENTS AND METHODS An Institutional Biosafety Committee-, Institutional Review Board-, Recombinant DNA Advisory Committee-, and US Food and Drug Administration-approved phase I study used intrapatient dose escalation of adenoviral vector containing a herpes simplex thymidine kinase gene (AdV-TK) followed by systemic administration of ganciclovir to treat bilateral retinoblastoma with vitreous tumor seeding refractory to standard therapies. Vitreous tumor seeds were treated by intravitreous injection of AdV-TK adjacent to disease sites. Each injection was followed by ganciclovir delivered intravenously every 12 hours for 7 days. RESULTS Eight patients with vitreous tumor seeds were enrolled. One patient who was treated with 10(8) viral particles (vp) had resolution of the tumor seeds around the injection site. The seven patients who were treated with doses > or = 10(10) vp had resolution of their vitreous tumor seeds documented by fundoscopy. Toxicity included mild inflammation at 10(10) vp and moderate inflammation, corneal edema, and increased intraocular pressure at 10(11) vp. One patient was free of active vitreous tumor seeds 38 months after therapy. There has been no evidence of extraocular spread of tumor along the needle tract in any patient. CONCLUSION AdV-TK followed by ganciclovir can be administered safely to children with retinoblastoma. Suicide gene therapy may contribute to the treatment of children with retinoblastoma tumor seeds in the vitreous, a resistant complication of retinoblastoma.

Autologous Antileukemic Immune Response Induced by Chronic Lymphocytic Leukemia B Cells Expressing the CD40 Ligand and Interleukin 2 Transgenes

Although the B cells of chronic lymphocytic leukemia (B-CLL cells) express both tumor-specific peptides and major histocompatibility complex (MHC) class I antigens, they lack the capacity for costimulatory signaling, contributing to their protection against host antitumor immunity. To stimulate CLL-specific immune responses, we sought to transfer the human CD40 ligand (hCD40L) gene to B-CLL cells, using an adenoviral vector, in order to upregulate costimulating factors on these cells. Because efficient gene transduction with adenoviral vectors requires the expression of virus receptors on target cells, including the coxsackievirus B-adenovirus receptors (CAR) and alpha(v) integrins, we cocultured B-CLL cells with human embryonic lung fibroblasts (MRC-5 line). This exposure led to increased expression of integrin alpha(v)beta3 on B-CLL cells, which correlated with higher transduction rates. Using this novel prestimulation system, we transduced B-CLL cells with the hCD40L gene. The Ad-hCD40L-infected cells had higher expression of B7 molecules and induced activation of autologous T cells in vitro, but these T cells could not recognize parental leukemic cells. By contrast, an admixture of Ad-hCD40L-positive cells and leukemic cells transduced with the human interleukin 2 (IL-2) gene produced greater T cell activation than did either immunostimulator population alone. Importantly, this combination generated autologous T cells capable of specifically recognizing parental B-CLL cells. These findings suggest that the combined use of genetically modified CD40L-expressing B-CLL cells in combination with IL-2-expressing B-CLL cells may induce therapeutically significant leukemia-specific immune responses.

Metastatic and Nonmetastatic Models of Retinoblastoma

To generate animal models of retinoblastoma that closely resemble metastatic and nonmetastatic human disease for the purposes of examining tumor biology and developing alternate treatments, human retinoblastoma cell lines were injected into the vitreal cavities of immunodeficient mice. Two reproducible animal models with contrasting biological behaviors analogous to human retinoblastoma have been developed. The Y79 retinoblastoma model demonstrated specific tumor evolution similar to that seen in human invasive and metastatic disease. Y79 retinoblastoma cells formed intraocular tumors that were initially confined to the vitreal cavity. Tumors progressively invaded the retina, subretinal space, choroid, optic nerve head, and anterior chamber of the eye. Tumors progressed into the subarachnoid space and focally invaded the brain. Metastases were detected in the contralateral optic nerve. Large tumors developed extraocular extensions. The histology of the tumors showed a poorly differentiated pattern with high mitotic rate, foci of necrosis, and calcification. The WERI-Rb model more closely resembled nonmetastatic human retinoblastoma. WERI- Rb tumors were localized in the eye with only anterior choroidal invasion at late stages. To examine potential biological differences in vitro, the retinoblastoma cell lines were cocultured with adherent choroid cells or adherent glioma cells which represent the targets of invasive retinoblastoma in vivo. Consistent with the in vivo observations, Y79 cells but not WERI-Rb cells adhere specifically to both the choroidal and the glioma cell lines.

Suicide gene therapy for treatment of retinoblastoma in a murine model.

Children presenting with large retinoblastomas are currently treated by enucleation. As most patients are young children, the long-term repercussions of such surgery are often devastating. Subsequent radiation or chemotherapy, although effective in managing residual tumor, greatly increase the probability of the development of second malignancies later in life. Smaller tumors can sometimes be managed with local cryo- or laser surgery, thus saving the eye. The hypothesis that gene therapy could be used to reduce the tumor size sufficiently to allow local control was tested using a murine model of retinoblastoma. Y79Rb human retinoblastoma cells can be killed in vitro when transduced with an adenoviral vector containing the herpes simplex thymidine kinase gene (AdV-TK) followed by treatment with the prodrug ganciclovir. Intravitreal injections of Y79Rb cells in immunodeficient mice produce an aggressive, metastatic murine model of retinoblastoma. When these murine retinoblastomas were transduced in vivo with AdV-TK and the animals treated with intraocular injections of ganciclovir, 70% showed a complete ablation of detectable tumor. Treated animals had a significant prolongation of progression-free survival as compared with untreated controls. Gene therapy effectively reduced the tumor burden in this murine model of retinoblastoma. Thus gene therapy, in conjunction with local surgical control, may provide an effective alternative to enucleation, systemic chemotherapy, or radiotherapy for treatment of large, nonmetastatic retinoblastomas in children.

Chronic relapsing thrombotic thrombocytopenic purpura in infants with large von Willebrand factor multimers during remission

We studied two children with recurrent schistocytic hemolytic anemia and thrombocytopenia beginning in the neonatal period. One patient had a stroke during one of the episodes of thrombotic thrombocytopenic purpura. The presence of unusually large von Willebrand factor multimers was demonstrated in both children during clinical and hematologic remissions. Treatment with corticosteroids and intravenous injections of immune globulin was unsuccessful in the one patient who received it. Immediate improvement occurred in both patients after the infusion of fresh-frozen plasma. Symptoms of thrombocytopenia continue to recur at regular intervals in the absence of periodic fresh-frozen plasma infusions. One of these children apparently has chronic relapsing thrombotic thrombocytopenic purpura; the second has a chronic relapsing disorder similar to thrombotic thrombocytopenic purpura.

Expression of the functional cone phototransduction cascade in retinoblastoma.

Retinoblastoma is a malignant intraocular tumor that primarily affects small children. These tumors are primitive neuroectodermal malignancies, however some of them show morphologic evidence of differentiation into photoreceptors. Phototransduction cascades are a series of biochemical reactions that convert a photon of light into a neural impulse in rods and cones. The components of these cascades are uniquely expressed in photoreceptors and, although functionally similar, distinct components of these cascades are expressed in rods and cones. Using HPLC anion exchange chromatography, Western blot analysis, and specific monoclonal and polyclonal antibodies, we found that the cone but not the rod cGMP phosphodiesterase is functionally expressed in all six primary retinoblastomas examined and in three continuous retinoblastoma cell lines. Morphologic evidence of differentiation did not correlate with the expression of the enzyme. Furthermore, GTP analogues could activate the phosphodiesterase activity suggesting that an intact phototransduction cascade is present in the tumors. The presence of the cone phototransduction cascade in retinoblastoma confirms that this tumor has biochemically differentiated along the cone cell lineage.

Extensively necrotic retinoblastoma is associated with high-risk prognostic factors

CONTEXT Retinoblastoma is the most common malignant intraocular tumor in children. It has been shown that adjuvant therapy following enucleation in patients with high-risk histopathologic features significantly decreases the mortality. We describe the association of extensive necrosis of tumor and intraocular structures with 2 of the major risk factors: optic nerve invasion and choroidal invasion. This may alert the pathologist who makes the observation of extensive necrosis to carefully search for histologic features associated with adverse outcome. OBJECTIVE To determine whether extensively necrotic retinoblastoma is associated with high-risk histologic prognostic factors for metastatic disease and patient survival. DESIGN Retrospective case series. Forty-three eyes of 43 patients with retinoblastoma who underwent enucleation between 1990 and 2001 were evaluated. Medical records, histopathology specimens, pathology reports, and clinical photographs were reviewed. Tumors were designated as exhibiting extensive necrosis if more than 95% of tumor cells and intraocular tissues were necrotic. The main outcome measure was the association of extensive tumor necrosis with 3 high-risk histopathologic features: extraocular extension, optic nerve invasion, or choroidal invasion. Metastatic disease, patient survival, and associations with pathologic findings were also analyzed. RESULTS Optic nerve head invasion (P < .001), post-lamina-cribrosal invasion (P < .001), and choroidal invasion by tumor (P = .004) were observed more frequently in eyes with extensive necrosis compared with eyes without extensive necrosis. Two of the 11 patients with extensively necrotic intraocular retinoblastoma died from metastatic disease (P = .06). None of the 32 patients without extensive necrosis developed metastatic disease or died. CONCLUSIONS Extensive ocular tissue and tumor necrosis is associated with histologic high-risk prognostic factors for tumor metastasis and mortality.

A single intravenous injection of oncolytic picornavirus SVV-001 eliminates medulloblastomas in primary tumor-based orthotopic xenograft mouse models

Difficulties of drug delivery across the blood-brain barrier (BBB) and failure to eliminate cancer stem cells (CSCs) are believed to be the major causes of tumor recurrences in children with medulloblastoma (MB). Seneca Valley virus-001 (SVV-001) is a naturally occurring oncolytic picornavirus that can be systemically administered. Here, we report its antitumor activities against MB cells in a panel of 10 primary tumor-based orthotopic xenograft mouse models. We found that SVV-001 killed the primary cultured xenograft cells, infected and replicated in tumor cells expressing CSC surface marker CD133, and eliminated tumor cells capable of forming neurospheres in vitro in 5 of the 10 xenograft models. We confirmed that SVV-001 could pass through BBB in vivo. A single i.v. injection of SVV-001 in 2 anaplastic MB models led to widespread infection of the preformed intracerebellar (ICb) xenografts, resulting in significant increase in survival (2.2-5.9-fold) in both models and complete elimination of ICb xenografts in 8 of the 10 long-term survivors. Mechanistically, we showed that the intracellular replication of SVV-001 is mediated through a subverted autophagy that is different from the bona fide autophagic process induced by rapamycin. Our data suggest that SVV-001 is well suited for MB treatment. This work expands the current views in the oncolytic therapy field regarding the utility of oncolytic viruses in simultaneous targeting of stem and nonstem tumor cells.

Treatment of invasive retinoblastoma in a murine model using an oncolytic picornavirus

Retinoblastoma, the most common intraocular malignancy of childhood, metastasizes by initial invasion of the choroid and the optic nerve. There is no effective treatment for metastatic retinoblastoma, especially when the central nervous system (CNS) is involved, and prevention of this complication is a treatment priority. Seneca Valley Virus (SVV-001) is a conditionally replication-competent picornavirus that is not pathogenic to normal human cells but can kill human retinoblastoma cells in vitro with an IC(50) of <1 viral particle (vp) per cell. A xenograft murine model of metastatic retinoblastoma was used to examine the therapeutic potential of SVV-001. Histopathologic analysis of ocular and brain tissues after a single tail vein injection of SVV-001 (1 x 10(13) vp/kg) showed effective treatment of choroid and ocular nerve tumor invasion (1 of 20 animals with invasive disease in the treated group versus 7 of 20 animals with invasive disease in the control group; P = 0.017) and prevention of CNS metastasis (0 of 20 animals with CNS metastatic disease in the treated group versus 4 of 20 animals with CNS disease in the control group; P = 0.036). There were no observed adverse events due to the virus in any of the treated animals. SVV-001 may be effective as a treatment of locally invasive and metastatic retinoblastoma.