Curcumin-induced HDAC inhibition and attenuation of medulloblastoma growth in vitro and in vivo

<p>Abstract</p> <p>Background</p> <p>Medulloblastoma is the most common brain tumor in children, and its prognosis is worse than for many other common pediatric cancers. Survivors undergoing treatment suffer from serious therapy-related side effects. Thus, it is imperative to identify safer, effective treatments for medulloblastoma. In this study we evaluated the anti-cancer potential of curcumin in medulloblastoma by testing its ability to induce apoptosis and inhibit tumor growth <it>in vitro </it>and <it>in vivo </it>using established medulloblastoma models.</p> <p>Methods</p> <p>Using cultured medulloblastoma cells, tumor xenografts, and the Smo/Smo transgenic medulloblastoma mouse model, the antitumor effects of curcumin were tested <it>in vitro </it>and <it>in vivo</it>.</p> <p>Results</p> <p>Curcumin induced apoptosis and cell cycle arrest at the G2/M phase in medulloblastoma cells. These effects were accompanied by reduced histone deacetylase (HDAC) 4 expression and activity and increased tubulin acetylation, ultimately leading to mitotic catastrophe. In <it>in vivo </it>medulloblastoma xenografts, curcumin reduced tumor growth and significantly increased survival in the Smo/Smo transgenic medulloblastoma mouse model.</p> <p>Conclusions</p> <p>The <it>in vitro </it>and <it>in vivo </it>data suggest that curcumin has the potential to be developed as a therapeutic agent for medulloblastoma.</p

Abstract 4573: Inhibition of tumor growth by human IgM-isotype monoclonal antibody to ganglioside GD2

Abstract Monoclonal antibody, MORAb-028, a human IgM derived from patients with melanoma, specifically binds to tumor cell surface ganglioside-GD2 with high specificity, and kills GD2-expressing target cells via complement-mediated cytotoxicity (CDC). This CDC-mediated anti-tumor activity of MORAb-028 has been confirmed in vitro using various GD2-expressing tumor cells in presence of rat sera. In the present study, intraperitoneal (i.p) and intratumoral (i.t.) treatment models in nude rats were developed to investigate in vivo anti-tumor activity of MORAb-028. These compartmental models provide an in vivo system to monitor IgM anti-tumor activity that has not been possible in previous studies due to the rodent poly-Ig-Receptor (PIgR) that is able to sequester systemically administered hIgM in the liver thereby lowering serum IgM steady-state levels that in turn lowers distribution of IgM to targeted tumors. In the present study, murine EL4-luc2 cells that express high levels of GD2 were engineered to express a luciferase-reporter-gene enabling in vivo bioluminescent detection for monitoring tumor status. These cells were used in two different models to test the ability of MORAb-028 to impact tumor growth. An i.p. model was developed whereby tumor cells were injected directly into the peritoneal cavity of nude rats followed immediately by a single i.p. dose of MORAb-028 at 3mg/kg, a dose that has showed activity in vitro. Tumor progression was monitored by bioluminescence using IVIS living imaging system. On day 24 post treatment, a significant reduction in tumor progression was observed in the MORAb-028-treated animals in comparison to the control. Only minimal tumor growth (∼3 to 5 mm3) was observed in MORAb-028-treated animals in contrast to control animals, in which tumor occupied the entire peritoneal cavity. In a second model EL-4-luc cells were implanted subcutaneously and antibody was directly administered to palpable tumors. Here, a single intratumoral injection of MORAb-028 was administered into established (300-400 mm3) tumors. Results showed that MORAb-028 treatment significantly inhibited tumor growth and eradicated nearly the entire tumor in ∼30% of the animals. Six days post treatment the tumor volume in MORAb-028-treated animals was ∼250 mm3, whereas the tumor volume was &amp;gt;1500mm3 in control animals. Animals with eradicated tumors showed no sign of recurrence at day 30 when the study was terminated. These data indicate that MORAb-028 is a potent agent to treat GD2-positive tumors in rat models. These results also suggest that this antibody may be useful in clinical applications for the treatment of GD2-positive human cancers. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4573. doi:10.1158/1538-7445.AM2011-4573</jats:p

Abstract 4410: Neutralizing Endosialin antibody, MORAb-004, enhances efficacy of TAXOTERE in a metastatic melanoma model

Abstract Endosialin/Tumor Endothelial Marker-1 (TEM1) is a cell surface glycoprotein that is expressed on cells involved in the development of tumor vasculature, primarily pericytes and stromal fibroblasts. Studies have found it to play a key role in tumor growth and neo-vessel formation in numerous cancer types. We are currently evaluating the safety and therapeutic potential of MORAb-004, a humanized monoclonal IgG targeting endosialin/TEM-1, in clinical trials. Because MORAb-004 only recognizes human antigen and has no cross-reactivity with rodent endosialin/TEM-1, we generated a human endosialin/TEM-1 knock-in mouse in order to assess its activity in vivo. Previously, in this transgenic model, we found that MORAb-004 significantly inhibited subcutaneous B16-F10 melanoma progression by ∼70% when administered intravenously for 5 consecutive days. Moreover, using the Lewis Lung Carcinoma model of metastatic disease our results showed that MORAb-004 had a significant inhibitory effect on the number of lung metastases. For these studies, supporting clinical trials for using MORAb-004 in combination with standard of care chemotherapeutics, we developed a B16-F10 melanoma lung colonization model. In this model, the human endosialin/TEM-1 knock-in mice were implanted intravenously with B16F10 cells adapted for in vivo lung colonization. These mice were treated with Docetaxel, MORAb-004, or the combination of the two agents, respectively. A group of the tumor-bearing mice receiving PBS served as control. At the end of the study, the lungs of each mouse were harvested. A ratio of the area of tumor nodules versus total lung surface area is calculated as tumor burden. MORAb-004, at 50 mg/kg three times weekly for a total of 7 i.v. injections reduced tumor burden by 45%. Treatment of Docetaxel, at 3mg/kg twice weekly for a total of 5 i.p. injections, reduced less than 20% of tumor burden in the lungs. When MORAb004 was added to Docetaxel treatment, a significant enhancement of efficacy was observed. The reduction of tumor nodules in the lungs was increased to approximately 70%. A similar trend is seen in combination therapy where MORAb-004 was added to gemcitabine regimen. Our results demonstrate the ability of MORAb-004 to inhibit tumor growth in a murine model. Moreover, when added to the chemotherapeutic regimen, it significantly enhances the therapeutic effect of traditional chemotherapy. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4410. doi:1538-7445.AM2012-4410</jats:p

Antisense Oligonucleotides Selectively Regulate Aspartyl ␤-Hydroxylase and Its Truncated Protein Isoform in Vitro but Distribute Poorly into A549 Tumors in Vivo

ABSTRACT Alternative splicing of the human ␤-aspartyl (asparaginyl) hydroxylase (BAH) gene results in the expression of humbug, a truncated form of BAH that lacks the catalytic domain of the enzyme. Overexpression of BAH and humbug has been associated with a variety of human cancers, and although humbug lacks enzymatic activity, it is expressed at levels comparable with that of BAH in various cancer cell lines. Phosphorothioate antisense oligonucleotides (ONs) were designed to dissect out the function of these hydroxylase protein isoforms. In A549 cells, these ONs differentially down-regulated BAH and humbug at the mRNA and protein level. Phosphorothioate ON uptake and antisense studies were conducted in parallel in nude mice bearing A549 tumor xenografts. Microscopic examination of the tumor after administration of a fluorescein-labeled ON showed strong labeling of the outer layers of the tumor connective tissue but cells within the interior of the tumor were sparsely labeled. A modest but significant effect on tumor growth was observed in animals treated with an antisense ON directed against both BAH and humbug transcripts. However, Northern analysis of tumor RNA did not indicate a down-regulation of the targeted mRNA species. These results demonstrate the successful development of antisense ONs that selectively differentiate between the closely related ␤-hydroxylase protein isoforms. However, determination of the biological function of these proteins in vivo was limited by the poor uptake properties of phosphorothioate ONs in A549 tumors