Necrotic Tumor Areas Research Articles

First-in-human phase I trial of NHS-IL12 in advanced solid tumors.

TPS2617 Background: NHS-IL12 is an antibody-cytokine conjugate consisting of two heterodimers of interleukin (IL)-12, fused to a human monoclonal antibody specific for DNA-histone H1 complex exposed in tumor necrosis. IL12 is a proinflammatory cytokine, produced by activated phagocytes and dendritic cells, that plays a critical role in regulating the transition from innate to adaptive immunity. Early clinical trials of IL12 reported clinical responses in metastatic renal cell carcinoma, Kaposi sarcoma (50–71% response rate), T-cell lymphoma (56%), and non-Hodgkin’s lymphoma (21%). However, systemic toxicity limited further clinical development. NHS-IL12 is designed to reduce toxicity associated with systemic administration of IL12 by selectively targeting delivery to necrotic areas of tumors. A fluorescence imaging study of NHS-murine (mu)-IL12 in mice with syngeneic lung carcinoma demonstrated effective targeting by NHS-muIL12. Immunohistochemistry studies further confirmed effective targeting of tumors by NHS-muIL12. In another study in canines with spontaneously occurring solid tumors, 2 of 11 subjects achieved a partial response with a single dose. Methods: This is a phase I dose-escalation study designed to determine the maximum tolerated dose of NHS-IL12 and to define the biologically optimal dose and schedule based on immunologic (pharmacodynamic) analysis of cytokines such as interferon-g, and IL-10, at multiple times points from 4 hours up to 2 weeks following the administration of NHS-IL12. Eligible patients (pts) include those with evaluable or measurable solid tumors who have progressive disease on at least one prior line of therapy. Pts with a condition associated with significant necrosis of non-tumor bearing tissue, (e.g., ulcerative colitis), are excluded. Modified immune-related response criteria are used to assess response, the major features of these criteria being (a) imaging confirmation of both progression and response at least 4 weeks after initial imaging, and (b) no consideration of new lesions unless the total measurable tumor burden meets the criteria for progressive disease. This trial opened to accrual in Nov. 2011 and may enroll up to 78 pts.

Role of apparent diffusion coefficient values for the differentiation of viable and necrotic areas of breast cancer and its potential utility to guide voxel positioning for MRS in the absence of dynamic contrast-enhanced MRI data

We carried out retrospective analysis of apparent diffusion coefficient (ADC) values in 48 infiltrating ductal breast cancer patients who had dynamic contrast-enhanced magnetic resonance imaging (DCEMRI; Group I) and in 53 patients (Group II) for whom DCEMRI data were not available. Twenty-three patients of Group I showed no necrosis (Group Ia), while in 25 patients, both viable (nonnecrotic) and necrotic tumor areas (Group Ib) were observed on DCEMRI. T1-weighted, fat-suppressed and short inversion recovery images were used to identify the viable and necrotic tumor areas in Group II patients, and necrosis was not seen in 11 patients (Group IIa), while 42 (Group IIb) showed both viable and necrotic tumor areas. The ADCs of the necrotic area of Group Ib (1.79±0.30 ×10−3 mm2/s) and Group IIb (1.83±0.40 ×10−3 mm2/s) patients were similar and significantly higher (P<.01) compared to the ADCs of the viable tumor area of Group Ia (0.96±0.21 ×10−3 mm2/s) and Group IIa (0.90±0.17 ×10−3 mm2/s) patients. Proton MR spectroscopy (MRS) data were also available in these patients, and the ADC values were retrospectively determined from the voxel from which MR spectrum was obtained. These values were compared with the ADC obtained for the viable and necrotic areas of the tumor. ADC of the MRS voxel was similar to that obtained for the viable tumor area in patients of both groups. This interesting observation reveals the potential utility of using ADC values to identify viable tumor area for positioning of voxel for MRS in the absence of DCEMRI data.

Imaging of Tumor Viability in Lung Cancer: Initial Results Using 23Na-MRI

23Na-MRI has been proposed as a potential imaging biomarker for the assessment of tumor viability and the evaluation of therapy response but has not yet been evaluated in patients with lung cancer. We aimed to assess the feasibility of 23Na-MRI in patients with lung cancer. Three patients with stage IV adenocarcinoma of the lung were examined on a clinical 3 Tesla MRI system (Magnetom TimTrio, Siemens Healthcare, Erlangen, Germany). Feasibility of 23Na-MRI images was proven by comparison and fusion of 23Na-MRI with 1H-MR, CT and FDG-PET-CT images. 23Na signal intensities (SI) of tumor and cerebrospinal fluid (CSF) of the spinal canal were measured and the SI ratio in tumor and CSF was calculated. One chemonaive patient was examined before and after the initiation of combination therapy (Carboplatin, Gemcitabin, Cetuximab). All 23Na-MRI examinations were successfully completed and were of diagnostic quality. Fusion of 23Na-MRI images with 1H-MRI, CT and FDG-PET-CT was feasible in all patients and showed differences in solid and necrotic tumor areas. The mean tumor SI and the tumor/CSF SI ratio were 13.3 ± 1.8 × 103 and 0.83 ± 0.14, respectively. In necrotic tumors, as suggested by central non-FDG-avid areas, the mean tumor SI and the tumor/CSF ratio were 19.4 × 103 and 1.10, respectively. 23Na-MRI is feasible in patients with lung cancer and could provide valuable functional molecular information regarding tumor viability, and potentially treatment response.

TNF-α induced secretion of HMGB1 from non-immune canine mammary epithelial cells (MTH53A)

Background Mammary neoplasias are one of the most frequent and spontaneously occurring malignancies in dogs and humans. Due to the similar anatomy of the mammary gland in both species, the dog has become an important animal model for this cancer entity. In human breast carcinomas, the overexpression of a protein named high-mobility group box 1 (HMGB1) was reported. Cells of the immune system were described to release HMGB1 actively exerting cytokine function. Thereby it is involved in the immune system activation, tissue repair, and cell migration. Passive release of HMGB1 by necrotic cells at sites of tissue damage or in necrotic hypoxic regions of tumors induces cellular responses e.g. release of proinflammatory cytokines leading to elevated inflammatory response and neo-vascularization of necrotic tumor areas. Herein we investigated if a time-dependent stimulation with the separately applied proinflammatory cytokines TNF-α and IFN-γ can cause secretion of HMGB1 in a non-immune related HMGB1-non-secreting epithelial canine mammary cell line (MTH53A) derived from non-neoplastic tissue. Methods The canine cell line was transfected with recombinant HMGB1 bicistronic expression vectors and stimulated after transfection with the respective cytokine independently for 6, 24 and 48 h. HMGB1 protein detection was performed by Western blot analysis and quantified a by enzyme-linked immunosorbent assay. Live cell laser scanning multiphoton microscopy of MTH53A cells expressing a HMGB1–GFP fusion protein was performed in order to examine, if secretion of HMGB1 under cytokine stimulating conditions is also visible by fluorescence imaging. Results The observed HMGB1 release kinetics showed a clearly time-dependent manner with a peak release 24 h after TNF-α stimulation, while stimulation with IFN-γ had only small effects on the HMGB1 release. Multiphoton HMGB1 live cell microscopy showed diffuse cell membrane structure changes 29 h after cytokine-stimulation but no clear secretion of HMGB1–GFP after TNF-α stimulation was visible. Conclusion Our results demonstrate that non-immune HMGB1-non-secreting cells of epithelial origin derived from mammary non-neoplastic tissue can be induced to release HMGB1 by single cytokine application. This indicates that tumor and surrounding tissue can be stimulated by tumor present inflammatory and necrotic cytokines to release HMGB1 acting as neo-vascularizing factor thus promoting tumor growth.

Synthesis and Characterization of Biodegradable and Thermosensitive Polymeric Micelles with Covalently Bound Doxorubicin-Glucuronide Prodrug via Click Chemistry

Doxorubicin is an anthracycline anticancer agent that is commonly used in the treatment of a variety of cancers, but its application is associated with severe side effects. Biodegradable and thermosensitive polymeric micelles based on poly(ethylene glycol)-b-poly[N-(2-hydroxypropyl) methacrylamide-lactate] (mPEG-b-p(HPMAmLac(n))) have been studied as drug delivery systems for therapeutic and imaging agents and have shown promising in vitro and in vivo results. The purpose of this study was to investigate the covalent coupling of a doxorubicin-glucuronide prodrug (DOX-propGA3) to the core of mPEG-b-p(HPMAmLac(2)) micelles. This prodrug is specifically activated by human β-glucuronidase, an enzyme that is overexpressed in necrotic tumor areas. To this end, an azide modified block copolymer (mPEG(5000)-b-p(HPMAmLac(2)-r-AzEMA)) was synthesized and characterized, and DOX-propGA3 was coupled to the polymer via click chemistry with a high (95%) coupling efficiency. Micelles formed by this DOX containing polymer were small (50 nm) and monodisperse and released 40% of the drug payload after 5 days incubation at 37 °C in the presence of β-glucuronidase, but less than 5% in the absence of the enzyme. In vitro cytotoxicity experiments demonstrated that DOX micelles incubated with 14C cells showed the same cytotoxicity as free DOX only in the presence of β-glucuronidase, indicating full conversion of the polymer-bound DOX into the parent drug. Overall, this novel system is very promising for enzymatically responsive anticancer therapy.

Assessment of Tumor Vascularization in Pancreatic Adenocarcinoma Using 128-Slice Perfusion Computed Tomography Imaging

Computed tomography (CT) perfusion studies can provide valuable information regarding tumor vascularization. We report on a study assessing CT perfusion characteristics in the normal pancreas and in patients with pancreatic adenocarcinoma. Twenty healthy subjects and 20 patients with histologically confirmed pancreatic adenocarcinoma were included in the study after written informed consent and approval by our institutional review board. All subjects underwent perfusion CT imaging of the pancreas using 128-slice dual-source CT. The scanning sequence included 18 scans. Parametric maps of blood volume (BV), blood flow (BF), and permeability surface area product (PS) were generated and compared with density measurements. In normal pancreas, no significant difference in perfusion values was observed between head, body, and tail of the pancreas. Mean organ values were 76.76 (SD, 15.6) mL/100 g/min, 15.80 (SD, 2.40) mL/100 g, and 27.74 (SD, 16.8) mL/100 g/min for BF, BV, and PS, respectively. Compared with the normal pancreas, a 60% reduction in BF and BV was observed in the tumor tissue. Perfusion values gradually increased toward the tumor rim. Necrotic tumor areas were identified in 25% of patients. No significant differences were observed when comparing normal pancreas and healthy pancreatic tissue in adenocarcinoma patients. The feasibility of whole-tumor perfusion imaging using 128-slice CT was demonstrated in patients with pancreatic adenocarcinoma. Perfusion CT provides additional information compared with image assessment based on density measurements (Hounsfield units) and allows noninvasive assessment of vascularization in the tumor tissue.

Abstract 5398: A primer dose followed by low-bolus dose schedule for safe and efficacious bacterial tumor targeting with S. typhimurium A1-R

Abstract We have previously developed a bacterial cancer therapy strategy by targeting viable tumor tissue with Salmonella typhimurium containing two auxotrophic mutations. These auxotrophs grow in viable as well as necrotic areas of tumors. However, the auxotrophy severely restricts growth of these bacteria in normal tissue, making this a relative safe treatment. The S. typhimurium A1-R mutant, which is auxotrophic for leu-arg, and selected for high antitumor virulence, has been shown to be effective as monotherapy against human prostate, breast, pancreatic, and fibrosarcoma tumors that have been orthotopically implanted in nude mice. In the present study, we developed a strategy to maximize efficacy and minimize toxicity for bacterial tumor treatment. A small dose of S. typhimurium A1-R bacteria was first administered to tumor-bearing animals (the primer dose) as pre-treatment followed by a high dose (106 i.v.) 4 hours later. Compared with very high dose bacteria treatment (5 × 106 per mouse), the primer dose strategy had no observable side effects. The very high dose had toxicity in immunocompetent mice. The primer dose may induce cytokines in the mouse necessary for invasion of the tumor by the bacteria allowing a relatively small subsequent dose to be effective and safe. 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 5398. doi:10.1158/1538-7445.AM2011-5398

Biopsy Targeting Gliomas

Because of the heterogeneous nature of glioma, biopsies performed should be targeted at the most anaplastic region. Several functional magnetic resonance imaging (MRI) or positron emission tomography (PET) techniques have been proposed for identifying the most anaplastic tumor area. However, it is unclear whether the recommended biopsy targets based on these various functional imaging modalities correspond with each other. Thus, the purpose was to evaluate whether they identify similar target areas. A total of 61 patients with suspected glioma were assessed within 2.3 +/- 3.5 days by MRI, 18F-fluorothymidine-, and 18F-fluorodeoxyglucose-PET. Thirty-five patients underwent gross total resection and 26 were stereotactically biopsied. MRI was performed on a 1.5 Tesla broadband transmit/receive system, using a double-resonant birdcage coil. The MRI protocol comprised of sodium (23Na)-MRI (3D-radial projection imaging), proton spectroscopic imaging (1H-MRSI, point-resolved spectroscopy), arterial spin-labeling (ASL) perfusion MRI, dynamic contrast-enhanced (DCE) MRI, and dynamic-susceptibility-weighted (DSC) perfusion MRI after a single dose each of gadobenate dimeglumine. Also, apparent diffusion coefficient (ADC) maps were processed from diffusion tensor images. Image analysis comprised a detailed semiquantitative region of interest analysis of the different parameter values as well as visual identification of the most conspicuous tumor areas on parameter maps, for example, areas with maximum tumor perfusion, highest metabolite ratios of choline-containing compounds/N-acetyl-aspartate, or lowest ADC values within tumor tissue. Colocalization of these areas was then assessed. Regarding tumor vascularity-related parameters and tumor proliferation-related parameters, the higher the glioma grade the higher were the respective parameters in semiquantitative analysis. ADC values decreased with glioma grade. In the whole study population comprising low- (N = 15) and high-grade gliomas (N = 42), except for 23Na-MRI, there was good (>50%) or perfect (100%) agreement of the tumor areas with highest values on parameter images in the majority of cases (>80%), that is, tumor areas with increased thymidine-uptake and highest choline, both suggestive of increased tumor proliferation, and elevated microcirculation as demonstrated by DSC-, arterial spin-labeling-, and DCE-MRI. 23Na-MRI depicted the highest signal within necrotic tumor areas, but non-necrotic gliomas also showed a perfect agreement in more than 61%. 18F-fluorothymidine-PET, DSC-, and DCE-MRI, diffusion-weighted imaging as well as MR spectroscopic imaging correctly detected no glioma heterogeneity in all 15 histologically proven grade II gliomas but identified suspicious areas in all 3 nonenhancing grade III gliomas. Both imaging techniques that depict microcirculation and techniques that visualize proliferation identify similar target areas.

Multimodal Mass Spectrometric Imaging of Small Molecules Reveals Distinct Spatio-Molecular Signatures in Differentially Metastatic Breast Tumor Models

Phosphocholine (PC) and total choline (tCho) are increased in malignant breast tumors. In this study, we combined magnetic resonance spectroscopic imaging (MRSI), mass spectrometry (MS) imaging, and pathologic assessment of corresponding tumor sections to investigate the localization of choline metabolites and cations in viable versus necrotic tumor regions in the nonmetastatic MCF-7 and the highly metastatic MDA-MB-231 breast cancer xenograft models. In vivo three-dimensional MRSI showed that high tCho levels, consisting of free choline (Cho), PC, and glycerophosphocholine (GPC), displayed a heterogeneous spatial distribution in the tumor. MS imaging performed on tumor sections detected the spatial distributions of individual PC, Cho, and GPC, as well as sodium (Na+) and potassium (K+), among many others. PC and Cho intensity were increased in viable compared with necrotic regions of MDA-MB-231 tumors, but relatively homogeneously distributed in MCF-7 tumors. Such behavior may be related to the role of PC and PC-related enzymes, such as choline kinase, choline transporters, and others, in malignant tumor growth. Na+ and K+ colocalized in the necrotic tumor areas of MDA-MB-231 tumors, whereas in MCF-7 tumors, Na+ was detected in necrotic and K+ in viable tumor regions. This may be attributed to differential Na+/K+ pump functions and K+ channel expressions. Principal component analysis of the MS imaging data clearly identified different tumor microenvironmental regions by their distinct molecular signatures. This molecular information allowed us to differentiate between distinct tumor regions and tumor types, which may, in the future, prove clinically useful in the pathologic assessment of breast cancers.

Targeted imaging of tumor-associated M2 macrophages using a macromolecular contrast agent PG-Gd-NIR813

Tumor-associated macrophages (TAMs) are diverse population containing multiple subtypes. M2 macrophages promote tumor growth and metastasis, in part by secreting a wide range of proangiogenic factors and growth factors. Selective depletion of M2 macrophages has been evaluated as a novel approach to anti-cancer therapy. In this study, a dual magneto-optical imaging probe, PG-Gd-NIR813 was synthesized and evaluated for non-invasive assessment of TAMs after intravenous injection. PG-Gd-NIR813 injected in nude rats bearing C6 tumors showed high uptake of the polymeric contrast agent in the tumor at 1 and 48 h after injection both in vivo and ex vivo optical imaging. T1-weighted MR imaging results showed accumulation of PG-Gd-NIR813 into the tumor necrotic area, which was confirmed by TUNEL staining of resected tumors. The uptake of PG-Gd-NIR813 within tumor necrosis decreased after animals were treated by the macrophage-depleting agent. Immunohistochemical staining demonstrated that PG-Gd-NIR813 colocalized with CD68 (marker for macrophages) and CD169 (marker for activated macrophages), but not with CD163 (residential macrophages). Using combined near-infrared fluorescence imaging and magnetic resonance imaging (MRI), we demonstrated that the accumulation of PG-Gd-NIR813 in tumors was mediated through M2 TAMs. Therefore, poly(l-glutamic acid) based reagents could be potentially used to image response to antitumor therapies targeted at M2 TAMs. Furthermore, poly(l-glutamic acid) is a promising carrier for candidate immunotherapeutics targeting M2 TAMs.

Abstract 2498: BNC105 is a tubulin polymerization inhibitor that exhibits vascular disruptive activity in renal cancer and causes upregulation in HIF1alpha, HIF2alpha and mTOR

Abstract BNC105 is a tubulin polymerization inhibitor. This agent selectively disrupts the vasculature in tumors, and in addition acts as a direct cytotoxic against cancer cells. BNC105 has demonstrated single agent efficacy in a number of cell lines and tumor models, including breast, colon, prostate, brain and lung cancer. We have investigated the activity of BNC105 in renal cancer cell lines and renal tumor xenografts. BNC105 exhibits cytotoxic activity with EC50 values in the range of 1-20nM. A number of other chemotherapeutic and targeted agents exhibit activity that is comparable or considerably lower than BNC105. Furthermore, we investigated the activity of BNC105 in disrupting the vasculature of tumors arising from human renal cancer cell lines. Our investigations included the renal cell lines Caki-1 and A498. Caki-1 cells express the wild type of the VHL gene, whereas A498 cells expresses a non-functional mutant form of VHL. In addition A498 cells do not express HIF1alpha. Somatic mutation of the VHL gene is the most frequent genetic alteration observed in renal cell carcinoma leading to inappropriate accumulation of HIF1alpha and HIF2alpha. Single dose BNC105 treatment of mice bearing tumor xenografts arising from these cell lines resulted in substantial tumor vascular disruption giving rise to large areas of tumor necrosis. Immunohistochemistry analysis revealed that expression of HIF1alpha was dramatically increased following BNC105 treatment in tumors arising from the renal cell line Caki-1. HIF1alpha expression in A498 tumors was restricted to endothelial cells and did not change following BNC105 treatment. HIF2alpha expression was found to be upregulated in cells surrounding areas of BNC105 induced necrosis in both Caki-1 and A498 tumors. These findings suggest that vascular disruption and necrosis caused by BNC105 lead to an angiogenic rebound effect that may contribute to tumor recovery from the vascular disruption insult. Given the key role of mTOR signaling in upregulation of HIF we examined the expression of phosphorylated mTOR in renal tumor xenografts following treatment with BNC105. Expression of phosphorylated mTOR was distinctly upregulated in viable cell zones surrounding tumor VDA-induced necrotic areas in both Caki-1 and A498 tumors. These findings suggest that tumor recovery from the necrotic insult of BNC105 is mediated through upregulation of mTOR activity. The potential benefit of combining BNC105 with mTOR inhibitors on the growth of renal tumors is currently being investigated. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2498.

Potentiating Effect of .BETA.-Glucans on Photodynamic Therapy of Implanted Cancer Cells in Mice

Photodynamic therapy (PDT) combines a drug or photosensitizer with a specific type of light to kill cancer cells. The cellular damage induced by PDT leads to activation of the DNA damage repair, which is an important factor for modulating tumor sensitivity to this treatment. beta-Glucans are natural polysaccharides that bind complement receptor 3 on the effector cells, thereby activating them to kill tumor cells during PDT. The hypothesis of the present study was that adjuvant therapy with beta-glucans would increase the efficacy of PDT. C57BL/6 female mice were subcutaneously implanted with Lewis lung carcinoma cells. Ten days after implantation, the mice were administered intravenously sodium porfimer (10 mg/kg) 24 h prior to laser irradiation, with or without oral administration of beta-glucan (400 microg/d/mouse, 5 days) from either barley, baker's yeast, or marine brown algae that contains the storage glucan, laminarin. Tumor volume and necrotic area in excised tumors were measured. The expression of proliferating cell nuclear antigen (PCNA) was determined as an indicator of the activity of the DNA damage repair system. PDT in combination with each beta-glucan significantly reduced tumor growth (P < 0.05, n = 10) and expression of PCNA (P < 0.001, n = 9), and increased necrosis in tumor tissues (P < 0.001, n = 9). Furthermore, each structurally different <beta-glucan exerted similar potentiating effects on PDT. The present findings show that beta-glucans enhance the tumor response to PDT, resulting in pronounced necrosis of PDT-treated tumors and suppression of the DNA damage repair system.

Vital microscopic analysis of polymeric micelle extravasation from tumor vessels: Macromolecular delivery according to tumor vascular growth stage

Particles larger than a specific size have been thought to extravasate from tumor vessels but not from normal vessels. Therefore, various nanoparticles incorporating anticancer drugs have been developed to realize selective drug delivery to solid tumors. However, it is not yet clear whether nanoparticles extravasate readily from all tumor vessels including vessels of microtumors. To answer this question, we synthesized new polymeric micelles labeled with fluorescein isothiocyanate (FITC) and injected them into the tail vein of rats with implanted skinfold transparent chambers. We also analyzed, by means of time-lapse vital microscopy with image analysis, extravasation of FITC micelles from tumor vessels at different stages of growth of Yoshida ascites sarcoma LY80. Polymeric micelles readily leaked from vessels at the interface between normal and tumor tissues and those at the interface between tumor tissues and necrotic areas. The micelles showed negligible extravasation, however, from the vascular network of microtumors less than 1 mm in diameter and did not accumulate in the microtumor. Our results suggest that we must develop a novel therapeutic strategy that can deliver sufficient nanomedicine to microtumors. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:549–562, 2010

Abstract A16: Antitumor activity of CYT997: A phase II vascular disrupting agent administered orally in combination with cisplatin in a colon adenocarcinoma xenograft model

Abstract CYT997 is an orally bioavailable small molecule vascular-disrupting agent (VDA) that is currently being investigated in Phase II clinical studies. In vitro efficacy studies have demonstrated that CYT997 exhibits potent antiproliferative activity against the DLD-1 cell line (IC50 21 nM), with a similar potency to doxorubicin, paclitaxel and vincristine (IC50 8 – 53 nM). The antitumor and vascular targeting activity of CYT997 has been demonstrated in the current series of studies following alternate dosing regimens (single dose vs metronomic sub-maximal daily dose) and in combination with a standard chemotherapeutic agent, cisplatin. Female Balb/C immunodeficient nude mice were implanted subcutaneously with DLD-1 human colon adenocarcinoma fragments and efficacy was assessed via tumor caliper measurements, in addition to histological assessment of tumor vascular shutdown (Hoechst 33342 staining) and necrotic area (haematoxylin and eosin staining). Animals were administered CYT997 (dihydrochloride salt) by oral gavage and efficacy was expressed relative to vehicle control. Administration of CYT997 resulted in a time and concentration dependent shutdown of tumor vasculature. Following a single CYT997 administration (40 mg/kg), vascular shutdown was extensive and rapid (ca 95% ablation compared with vehicle control at 1h post-dose; p&amp;lt;0.01). Significant vascular shutdown was maintained in tumors 4 days post treatment (ca 67% shutdown; p&amp;lt;0.05) and subsequent histological examination demonstrated increased necrosis (ca 280% increase; p&amp;lt;0.05) of the tumor in mice treated with CYT997 compared with vehicle control. A single oral dose at 10 mg/kg (ca 1/5th the maximum tolerated dose), resulted in statistically-significant shutdown of tumor vasculature in this model (61 – 94% shutdown at 1 h post-dose compared to vehicle control; p&amp;lt;0.05). Daily oral administration of CYT997 (10 mg/kg/day) resulted in sustained shutdown of tumor vasculature over 10 days of treatment (57% shutdown compared to vehicle control; p&amp;lt;0.05), which was associated with a significant increase (ca 44% increase; p&amp;lt;0.05) in the necrotic area of the tumor relative to control. The efficacy of the metronomic CYT997 dosing schedule was assessed in combination with weekly administration of cisplatin (6 mg/kg i.p.). Despite some toxicity associated with the second cycle of cisplatin administration, the greatest tumor growth delay was observed in the combination group (2.7 days), relative to cisplatin (1.9 days) or CYT997 (1.8 days) alone. These findings demonstrate that CYT997 exhibits rapid and long lasting antivascular effects following a single oral dose or following sub-maximal metronomic dosing. There is clear potential for increased anti-tumor efficacy when CYT997 is dosed in combination with other common anticancer therapies. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):A16.

Contrast Enhancement and Histopathological Findings in Vestibular Schwannoma

Changes of contrast uptake are considered to indicate the efficacy of therapy in irradiated vestibular schwannomas. We present a case of a large vestibular schwannoma with heterogeneous contrast uptake on MRI. Using neuronavigation, histological samples were obtained during surgery from an area with homogeneous contrast uptake and from a central tumor portion without contrast enhancement on MRI. Intraoperative investigation found no evidence of necrotic tumor, and histopathological examination revealed an active tumor in both sections, with no central necrosis. This finding illustrates the surgical experience that " necrotic tumor areas " on MRI may not be consistent with intraoperative findings. Lack of contrast uptake in previously irradiated schwannomas may not be indicative of effective radiotherapy.

Eosinophils Oxidize Damage-Associated Molecular Pattern Molecules Derived from Stressed Cells

Eosinophils (Eos) are found at increased numbers within necrotic areas of tumors. We show that necrotic material from cell lysates containing damage-associated molecular pattern molecules induce eosinophil degranulation (release of major basic protein and eosinophil peroxidase) and enhance their oxidative burst while the stimulatory capacity of cell lysates is significantly diminished following oxidation. High mobility group box 1 (HMGB1), a prototypic damage-associated molecular pattern molecule, released following necrosis but not apoptosis, induced a similar effect on Eos. Additionally, we demonstrate that HMGB1 enhances eosinophil survival and acts as a chemoattractant. Consistently, we show that Eos express an HMGB1 receptor, the receptor for advanced glycation end product, and that anti-receptor for advanced glycation end product could diminish the HMGB1-mediated effects. Of all tested biologic activities, Eos respond most sensitively to the presence of necrotic material including HMGB1 with generation of peroxide. We postulate that Eos "sense" necrotic cell death, migrating to and responding to areas of tissue injury/necrosis. Oxidation of cell lysates reduces their biologic activity when compared with native lysates. We postulate that eosinophil-associated modulation of immunity within tumor and other damaged tissues may be primarily by promoting oxidative degradation of necrotic material. Novel therapeutic strategies may be considered by advancing oxidative denaturation of released necrotic material using Eos or other aerobic strategies.

Early MRI response monitoring of patients with advanced hepatocellular carcinoma under treatment with the multikinase inhibitor sorafenib

BackgroundNew therapeutic principles in clinical oncology require the adjustment of response criteria to govern therapy decisions. For advanced hepatocellular carcinoma (HCC) a new era has recently begun by the approval of the multikinase inhibitor sorafenib. As a unique feature, HCC usually develops in a diseased liver and current imaging technologies employing classical response criteria have not been prospectively evaluated for this new treatment.MethodsMRI signal patterns were assessed in 21 advanced HCC patients receiving sorafenib. MRI was performed at baseline and in short-term intervals thereafter. Signal changes under therapy on T1WI, T2WI and post-gadolinium images including necrosis volume and its ratio to the entire tumor volume were compared to baseline imaging. To assess the association between the categorical variables, Fisher's exact tests were applied for a statistical analysis. Survey time ranged from 2–65 weeks, and a total of 39 target lesions were evaluated.ResultsSignal abnormalities during sorafenib therapy were disclosed by T1WI and T2WI in 15/21 patients. The predominant tumor signal change was hyperintensity on both T1WI and T2WI. Interestingly, most patients developed MRI signal changes within 4 weeks of therapy; in contrast, two non-responders did not show any signal alteration at follow-up. Under therapy, 16/21 patients presented with new or progressive necrosis, whereas 7 patients achieved temporarily >75% tumor necrosis under sorafenib. Significantly associated MRI variables were increase in T1WI signal and tumor necrosis (p = 0.017) as well as increase of tumor necrosis with an elevated ratio of necrotic to vital tumor areas (p = 0.002). Remarkably, some (3/13) of the patients developing necrotic tumor areas showed a relevant (>20%) increase in tumor volume, which should be considered in the assessment of imaging studies.ConclusionAs sorafenib induces early intralesional necrosis with profound changes in T1WI/T2WI MRI signal intensities and measurable necrotic tumor areas in most HCC patients, early MRI-based evaluation could pave the way for its rationale and cost-effective application.

Tumor-targeting amino acid auxotrophic Salmonella typhimurium

We have developed an effective bacterial cancer therapy strategy by targeting viable tumor tissue using Salmonella typhimurium auxotrophs that we have generated which grow in viable as well as necrotic areas of tumors. However, the auxotrophy severely restricts growth of these bacteria in normal tissue. The S. typhimurium A1-R mutant, which is auxotrophic for leu-arg and has high anti-tumor virulence, was developed in our laboratory. In vitro, A1-R infects tumor cells and causes nuclear destruction. A1-R was initially used to treat metastatic human prostate and breast tumors that had been orthotopically implanted in nude mice. Forty percent of treated mice were cured completely and survived as long as non-tumor-bearing mice. A1-R administered i.v. to nude mice with primary osteosarcoma and lung metastasis was highly effective, especially against metastasis. A1-R was also targeted to both axillary lymph and popliteal lymph node metastasis of human pancreatic cancer and fibrosarcoma, respectively, as well as lung metastasis of the fibrosarcoma in nude mice. The bacteria were delivered via a lymphatic channel to target the lymph node metastases and systemically via the tail vein to target the lung metastasis. The metastases were cured without the need of chemotherapy or any other treatment. A1-R was administered intratumorally to nude mice with an orthotopically transplanted human pancreatic tumor. The primary pancreatic cancer regressed without additional chemotherapy or any other treatment. A1-R was also effective against pancreatic cancer liver metastasis when administered intrasplenically to nude mice. The approach described here, where bacterial monotherapy effectively treats primary and metastatic tumors, is a significant improvement over previous bacterial tumor-therapy strategies that require combination with toxic chemotherapy. Three promoter clones engineered in S. enterica typhimurium were identified to have enhanced expression in bacteria growing in tumors relative to those growing in the spleen. The expression of therapeutics in Salmonella under the regulation of one or more promoters that are activated preferentially in tumors has the potential to improve the efficacy of Salmonella tumor therapy. Exploitation of the tumor-killing capability of Salmonella has great promise for a new paradigm of cancer therapy.

Novel Antitumor Effect of Carboplatin Delivered by Intracerebral Microinfusion in a Rat Malignant Glioma Model

Carboplatin loaded osmotic mini-pumps were implanted in 24 9L malignant glioma-bearing rats to investigate the implications of direct intracerebral microinfusion. Carboplatin using 0.1 mg/ml (low dose group) or 1.0 mg/ml (high dose group) with eight rats in each group, or 5% D-glucose (control group) in eight rats were infused at 1 microl/hr for 7 days. The tumor volume was serially measured by magnetic resonance (MR) imaging with gadolinium as the enhanced area, and the survival periods and histological findings were also examined. Separately, to examine the effects of intracerebral carboplatin infusion on vascular permeability, tumor-bearing rats received intravenous administration of 2% Evans blue at 21 days after infusion. The high dose group showed transient increase of enhanced volume at 21 days associated with mass effect, and significantly decreased tumor volume at 28 and 35 days compared with the control and low dose groups. The high dose group showed significant longer survival time than the control and low dose groups. Histological examination of the high dose group at 21 days showed the central tumor necrotic area around the infusion site and Evans blue leakage into the surrounding enhanced rim and the necrotic core. Therefore, leakage of plasma fluid into the necrotic area was considered to be the cause of apparent transient swelling. The present study demonstrated quantitatively using MR imaging that intracerebral carboplatin microinfusion significantly inhibited the rapid growth of experimental rat glioma but that the high dose required carries the risk of transient swelling of the target tumor.

Everolimus (RAD001)and anti-angiogenic cyclophosphamide show long-term control of gastric cancer growth in vivo

Metronomic dosing of cytotoxic drugs such as cyclophosphamide has shown anti-angiogenic activity, most likely by inducing hypoxia in tumors. Hypoxia leads to activation of escape mechanisms allowing tumor cell survival. This potentially limits the activity of anti-angiogenic strategies. We hypothesized that mTORC1 inhibition by everolimus (RAD001) leads to suppression of HIF-1α and VEGF resulting in synergistic anti-tumor activity in combination with anti-angiogenically dosed cyclophosphamide. In vitro, effects of everolimus on mTORC1 signaling, proliferation, cell cycle, HIF-1α expression and VEGF secretion were evaluated in two gastric cancer cell lines. In vivo, anti-tumor activity of everolimus in combination with metronomic cyclophosphamide was studied in a NCI-N87 human gastric cancer SCID mouse xenograft model. Expression of Ki-67 and HIF-1α, activated caspase 3, microvascular density (MVD) and tumor necrotic area was assessed.Everolimus decreased proliferation and attenuated production of HIF-1α as well as VEGF in gastric cancer cells in vitro. In vivo, everolimus significantly inhibited tumor growth. This anti-tumor activity was linked to a significant increase in tumor necrotic area (p