Malignant pleural mesothelioma (MPM) is a fatal disease with a median survival of less than 14 months. For the first time, a genetically engineered vaccinia virus is shown to produce efficient infection, replication, and oncolytic effect against MPM. GLV-1h68 is a replication-competent engineered vaccinia virus carrying transgenes encoding Renilla luciferase, green fluorescent protein (both inserted at the F14.5L locus), β-galactosidase (inserted at the J2R locus, which encodes thymidine kinase), and β-glucuronidase (at the A56R locus, which encodes hemagglutinin). This virus was tested in six human MPM cell lines (MSTO-211H, VAMT, JMN, H-2373, H-2452, and H-2052). GLV-1h68 successfully infected all cell lines. For the most sensitive line, MSTO-211H, expression of green fluorescent protein (GFP) started within 4 hr with increasing intensity over time until nearly 100% of cells expressed GFP at 24 hr. All cell lines were sensitive to killing by GLV-1h68, with the degree of sensitivity predictable by infectivity assay. Even the most resistant cell line exhibited 44 ± 3.8% cell survival by day 7 when infected at a multiplicity of infection of 1.0. Viral proliferation assays demonstrated 2-to 4-fold logarithmic replication of GLV-1h68 in the cell lines tested. In an orthotopic model, GLV-1h68 effectively prevented development of cachexia and tumor-related morbidity, reduced tumor burden, and cured MPM in both early and late treatment groups. GLV-1h68 was successfully used to treat MPM in vitro and in an orthotopic model (in vivo). These promising results warrant clinical investigation of GLV-1h68 as a novel agent in the treatment of MPM.

Purpose: Novel therapeutic regimens are needed to improve the dismal outcomes of patients with anaplastic thyroid cancer (ATC). Oncolytic herpes simplex virus have shown promising activity against human ATC. We studied the application of oncolytic herpes simplex virus (G207 and NV1023) in combination with currently used chemotherapeutic drugs (paclitaxel and doxorubicin) for the treatment of ATC. Experimental Design and Results: All four agents showed dose-response cytotoxicity in vitro for the human ATC cell lines KAT4 and DRO90-1. G207, combined with paclitaxel, showed synergistic cytotoxicity. Chou-Talalay combination indices ranged from 0.56 to 0.66 for KAT4, and 0.68 to 0.74 for DRO90-1 at higher affected fractions. Paclitaxel did not enhance G207 viral entry and early gene expression or G207 viral replication. Paclitaxel combined with G207 compared with single-agent treatment or controls showed significantly increased microtubule acetylation, mitotic arrest, aberrant chromatid separation, inhibition of metaphase to anaphase progression, and apoptosis. A single i.t. injection of G207 combined with biweekly i.p. paclitaxel injections in athymic nude mice bearing KAT4 flank tumors showed significantly reduced mean tumor volume (74 ± 38 mm³) compared with G207 alone (388 ± 109 mm³), paclitaxel alone (439 ± 137 mm³), and control (520 ± 160 mm³) groups at 16 days. There was no morbidity in vivo attributable to therapy. Conclusions: Mechanisms of paclitaxel antitumoral activity, including microtubule acetylation, mitotic block, and apoptosis, were enhanced by G207, which also has direct oncolytic effects. Combination of G207 and paclitaxel therapy is synergistic in treating ATC and holds promise for patients with this fatal disease.

This study was to investigate the clinical features and therapeutic outcomes of multifocal papillary thyroid microcarcinoma (PTMC). A total of 2,418 papillary thyroid carcinoma (PTC) patients had undergone thyroidectomy in one medical center between 1977 and 2010. There were 483 (20.0%) diagnosed with multifocal PTC. The percentage of multifocal PTC was higher in PTMC patients (22.0%) than in non-PTMC patients (19.5%). Demographic and clinical characteristics of PTMC and multifocal PTC in PTC patients were traced. Multifocal PTC patients presented with smaller tumors at an older age, and a higher percentage underwent total or complete thyroidectomy. These patients also showed a higher incidence of postoperative disease progression than did unifocal PTC patients. Comparison of 483 patients with multifocal PTMC and non-PTMC tumors showed a higher incidence of postoperative disease progression in patients with non-PTMC; otherwise, there was no statistical difference in disease-specific and total mortality between these two groups. In conclusion, the incidence of multifocal PTMC was not lower than that of non-PTMC, and postoperative therapies were necessary for both multifocal PTMC and non-PTMC patients.

Context: Anaplastic thyroid carcinoma (ATC) is a fatal disease with a median survival of only 6 months. Novel therapies are needed to improve dismal outcomes. Objective: A mutated, replication-competent, vaccinia virus (GLV-1h68) has oncolytic effects on human ATC cell lines in vitro. We assessed the utility of GLV-1h68 in treating anaplastic thyroid cancer in vivo. Design: Athymic nude mice with xenograft flank tumors of human ATCs (8505C and DRO90–1) were treated with a single intratumoral injection of GLV-1h68 at low dose (5 × 10⁵ plaque-forming unit), high dose (5 × 10⁶ plaque-forming unit), or PBS. Virus-mediated marker gene expression (luciferase, green fluorescent protein, and β-galactosidase), viral biodistribution, and flank tumor volumes were measured. Results: Luciferase expression was detected 2 d after injection. Continuous viral replication within tumors was reflected by increasing luciferase activity to d 9. At d 10, tumor viral recovery was increased more than 50-fold as compared with the injected dose, and minimal virus was recovered from the lung, liver, brain, heart, spleen, and kidneys. High-dose virus directly injected into normal tissues was undetectable at d 10. The mean volume of control 8505C tumors increased 50.8-fold by d 45, in contrast to 10.5-fold (low dose) and 2.1-fold (high dose; P = 0.028) increases for treated tumors. DRO90–1 tumors also showed significant growth inhibition by high-dose virus. No virus-related toxicity was observed throughout the study. Conclusions: GLV-1h68 efficiently infects, expresses transgenes within, and inhibits the growth of ATC in vivo. These promising findings support future clinical trials for patients with ATC.

We assessed the utility of the dual PI3K/mTOR inhibitor NVP-BEZ235 (BEZ235) as single agent therapy and in combination with conventional chemotherapy for thyroid cancer. Eight cell lines from four types of thyroid cancer (papillary, follicular, anaplastic, medullary) were studied. The cytotoxicity of BEZ235 and five conventional chemotherapeutic agents alone and in combination was measured using LDH assay. Quantitative western blot assessed expression of proteins associated with cell cycle, apoptosis and signaling pathways. Cell cycle distribution and apoptosis were measured by flow cytometry. Murine flank anaplastic thyroid cancers (ATC) were treated with oral BEZ235 daily. We found that BEZ235 effectively inhibited cell proliferation of all cancer lines, with ATC exhibiting the greatest sensitivity. BEZ235 consistently inactivated signaling downstream of mTORC1. BEZ235 generally induced cell cycle arrest at G0/G1 phase, and also caused apoptosis in the most sensitive cell lines. Baseline levels of p-S6 ribosomal protein (Ser235/236) and p27 correlated with BEZ235 sensitivity. Growth of 8505C ATC xenograft tumors was inhibited with BEZ235, without any observed toxicity. Combination therapy of BEZ235 and paclitaxel consistently demonstrated synergistic effects against ATC in vitro. BEZ235 as a single therapeutic agent inhibits thyroid cancer proliferation and has synergistic effects in combination with paclitaxel in treating ATC. These findings encourage future clinical trials using BEZ235 for patients with this fatal disease.