First Measurement of the Nuclear-Recoil Ionization Yield in Silicon at 100 eV

We measured the nuclear-recoil ionization yield in silicon with a cryogenic phonon-sensitive gram-scale detector. Neutrons from a monoenergetic beam scatter off of the silicon nuclei at angles corresponding to energy depositions from 4 keV down to 100 eV, the lowest energy probed so far. The results show no sign of an ionization production threshold above 100 eV. These results call for further investigation of the ionization yield theory and a comprehensive determination of the detector response function at energies below the keV scale.

A Review of In Vitro Instrumentation Platforms for Evaluating Thermal Therapies in Experimental Cell Culture Models

Thermal therapies, the modulation of tissue temperature for therapeutic benefit, are in clinical use as adjuvant or stand-alone therapeutic modalities for a range of indications, and are under investigation for others. During delivery of thermal therapy in the clinic and in experimental settings, monitoring and control of spatio-temporal thermal profiles contributes to an increased likelihood of inducing desired bioeffects. In vitro thermal dosimetry studies have provided a strong basis for characterizing biological responses of cells to heat. To perform an accurate in vitro thermal analysis, a sample needs to be subjected to uniform heating, ideally raised from, and returned to, baseline immediately, for a known heating duration under ideal isothermal condition. This review presents an applications-based overview of in vitro heating instrumentation platforms. A variety of different approaches are surveyed, including external heating sources (i.e., CO2 incubators, circulating water baths, microheaters and microfluidic devices), microwave dielectric heating, lasers or the use of sound waves. We discuss critical heating parameters including temperature ramp rate (heat-up phase period), heating accuracy, complexity, peak temperature, and technical limitations of each heating modality.

Constraints on Lightly Ionizing Particles from CDMSlite

The Cryogenic Dark Matter Search low ionization threshold experiment (CDMSlite) achieved efficient detection of very small recoil energies in its germanium target, resulting in sensitivity to lightly ionizing particles (LIPs) in a previously unexplored region of charge, mass, and velocity parameter space. We report first direct-detection limits calculated using the optimum interval method on the vertical intensity of cosmogenically produced LIPs with an electric charge smaller than e/(3×10^{5}), as well as the strongest limits for charge ≤e/160, with a minimum vertical intensity of 1.36×10^{-7}  cm^{-2} s^{-1} sr^{-1} at charge e/160. These results apply over a wide range of LIP masses (5  MeV/c^{2} to 100  TeV/c^{2}) and cover a wide range of βγ values (0.1-10^{6}), thus excluding nonrelativistic LIPs with βγ as small as 0.1 for the first time.

Light Dark Matter Search with a High-Resolution Athermal Phonon Detector Operated above Ground

We present limits on spin-independent dark matter-nucleon interactions using a 10.6 g Si athermal phonon detector with a baseline energy resolution of σ_{E}=3.86±0.04(stat)_{-0.00}^{+0.19}(syst)  eV. This exclusion analysis sets the most stringent dark matter-nucleon scattering cross-section limits achieved by a cryogenic detector for dark matter particle masses from 93 to 140  MeV/c^{2}, with a raw exposure of 9.9 g d acquired at an above-ground facility. This work illustrates the scientific potential of detectors with athermal phonon sensors with eV-scale energy resolution for future dark matter searches.

Understanding young peoples' and family members' views of treatment for first episode psychosis in a randomised controlled trial (MAPS)

BACKGROUND

There is limited evidence to inform treatment decision-making in adolescents experiencing first episode psychosis (FEP). In the MAPS trial (Managing Adolescent first Episode Psychosis: a feasibility Study), adolescents with FEP received either antipsychotic medication (AP), psychological intervention (PI), or both. We investigated treatment views of young people and family members across each treatment arm of MAPS.

METHODS

Thirteen adolescents participating in MAPS and eighteen family members attended in-depth audio-recorded interviews to discuss trial treatments. Interviews were analysed using inductive Thematic Analysis, identifying salient themes across these accounts.

FINDINGS

Family members in particular reported an urgent need for treatment regardless of type. Both AP and PI were broadly viewed as acceptable treatment approaches, but for differing reasons which participants weighed against a range of concerns. AP were often seen to reduce symptoms of psychosis, though participants expressed concerns about side effects. PI were viewed as interactive treatment approaches that helped improve understanding of psychosis and enhanced coping, although some found PI emotionally and cognitively challenging. Combining treatments was seen to maximise benefits, with a perceived interaction whereby AP facilitated engagement with PI.

INTERPRETATION

Acceptability of and engagement with treatments for FEP may differ between individual young people and their family/carers. In order to be able to offer fully informed choices, and determine an optimum treatment approach for young people with FEP, definitive trial evidence should be established to determine wanted and unwanted treatment impacts.

FUNDING

NIHR HTA programme (project number 15/31/04).

Temperature estimation for MR-guided microwave hyperthermia using block-based compressed sensing. Annu Int Conf IEEE Eng Med Biol Soc 2020;2020:5057-5060. [PMID: 33019123 DOI: 10.1109/embc44109.2020.9176206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Mild hyperthermia has been clinically employed as an adjuvant for radiation/chemotherapy and is under investigation for precise thermally-mediated delivery of cancer therapeutic agents. Magnetic Resonance Imaging (MRI) facilitates non-invasive, real-time spatial thermometry for monitoring and guiding hyperthermia procedures. Long image acquisition time during MR-guided hyperthermia may fail to capture rapid changes in temperature. This may lead to unwanted heating of healthy tissue and/or temperature rise above hyperthermic range. We have developed a block-based compressed sensing approach to reconstruct volumetric MR-derived microwave hyperthermia temperature profiles using a subset of measured data. This algorithm exploits the sparsity of MR images due to the presence of inter- and intra-slice correlation of hyperthermic MR-derived temperature profiles. We have evaluated the performance of our developed algorithm on a phantom and in vivo in mice using previously implemented microwave applicators. This algorithm reconstructs 3D temperature profiles with PSNR of 33 dB - 49 dB in comparison to the original profiles. In summary, this study suggests that microwave hyperthermia induced temperature profiles can be reconstructed using subsamples to reduce MR image acquisition time.

Erratum: First Dark Matter Constraints from a SuperCDMS Single-Charge Sensitive Detector [Phys. Rev. Lett. 121, 051301 (2018)]

This corrects the article DOI: 10.1103/PhysRevLett.121.051301.

First Dark Matter Constraints from a SuperCDMS Single-Charge Sensitive Detector

We present the first limits on inelastic electron-scattering dark matter and dark photon absorption using a prototype SuperCDMS detector having a charge resolution of 0.1 electron-hole pairs (CDMS HVeV, a 0.93 g CDMS high-voltage device). These electron-recoil limits significantly improve experimental constraints on dark matter particles with masses as low as 1  MeV/c^{2}. We demonstrate a sensitivity to dark photons competitive with other leading approaches but using substantially less exposure (0.49 g d). These results demonstrate the scientific potential of phonon-mediated semiconductor detectors that are sensitive to single electronic excitations.

Abstract 1481: Selective protein expression in tumor cells controlled by progression elevated gene-3 promoter

The progression elevated gene-3 (PEG-3) promoter is a rodent gene that has shown strong activity in tumor progression. Demonstrating tumor specificity and activity in at least five different human cancers, PEG-3 is considered a novel promoter for tumor-specific gene expression. Understanding how PEG-3 controls expression of reporter proteins is of biomedical significance because of the role it could play in new therapeutic strategies against certain types of cancer. In this study, we aim to use the PEG-3 promoter to observe the expression of firefly luciferase 2 (luc 2), a bioluminescent reporter protein, in the transfection of mammalian cells. Ultimately, we plan to use PEG-3 to express a therapeutic gene, cytosine deaminase, in cancer specific areas of breast, lung, and ovary.

Citation Format: Ruben Pando, Tej Shrestha, Marla Pyle, Deryl Troyer. Selective protein expression in tumor cells controlled by progression elevated gene-3 promoter [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1481.

Results from the Super Cryogenic Dark Matter Search Experiment at Soudan

We report the result of a blinded search for weakly interacting massive particles (WIMPs) using the majority of the SuperCDMS Soudan data set. With an exposure of 1690 kg d, a single candidate event is observed, consistent with expected backgrounds. This analysis (combined with previous Ge results) sets an upper limit on the spin-independent WIMP-nucleon cross section of 1.4×10^{-44} (1.0×10^{-44})  cm^{2} at 46  GeV/c^{2}. These results set the strongest limits for WIMP-germanium-nucleus interactions for masses >12  GeV/c^{2}.

Peptide nanosponges designed for rapid uptake by leukocytes and neural stem cells

The structure of novel binary nanosponges consisting of (cholesterol-(K/D)_nDEVDGC)₃-trimaleimide units possessing a trigonal maleimide linker, to which either lysine (K)₂₀ or aspartic acid (D)₂₀ are tethered, has been elucidated by means of TEM. A high degree of agreement between these findings and structure predictions through explicit solvent and then coarse-grained molecular dynamics (MD) simulations has been found. Based on the nanosponges' structure and dynamics, caspase-6 mediated release of the model drug 5(6)-carboxyfluorescein has been demonstrated. Furthermore, the binary (DK20) nanosponges have been found to be virtually non-toxic in cultures of neural progenitor cells. It is of a special importance for the future development of cell-based therapies that DK20 nanosponges were taken up efficiently by leucocytes (WBC) in peripheral blood within 3 h of exposure. The percentage of live cells among the WBC was not significantly decreased by the DK20 nanosponges. In contrast to stem cell or leucocyte cell cultures, which have to be matched to the patient, autologous cells are optimal for cell-mediated therapy. Therefore, the nanosponges hold great promise for effective cell-based tumor targeting.

Nanosponges for drug delivery.

An integrated platform for small-animal hyperthermia investigations under ultra-high-field MRI guidance

PURPOSE

Integrating small-animal experimental hyperthermia instrumentation with magnetic resonance imaging (MRI) affords real-time monitoring of spatial temperature profiles. This study reports on the development and preliminary in vivo characterisation of a 2.45 GHz microwave hyperthermia system for pre-clinical small animal investigations, integrated within a 14 T ultra-high-field MRI scanner.

MATERIALS AND METHODS

The presented system incorporates a 3.5 mm (OD) directional microwave hyperthermia antenna, positioned adjacent to the small-animal target, radiating microwave energy for localised heating of subcutaneous tumours. The applicator is integrated within the 30 mm bore of the MRI system. 3D electromagnetic and biothermal simulations were implemented to characterise hyperthermia profiles from the directional microwave antenna. Experiments in tissue mimicking phantoms were performed to assess hyperthermia profiles and validate MR thermometry against fibre-optic temperature measurements. The feasibility of delivering in vivo hyperthermia exposures to subcutaneous 4T1 tumours in experimental mice under simultaneous MR thermometry guidance was assessed.

RESULTS

Simulations and experiments in tissue mimicking phantoms demonstrated the feasibility of heating 21-982 mm³ targets with 8-12 W input power. Minimal susceptibility and electrical artefacts introduced by the hyperthermia applicator were observed on MR imaging. MR thermometry was in excellent agreement with fibre-optic temperatures measurements (max. discrepancy ≤0.6 °C). Heating experiments with the reported system demonstrated the feasibility of heating subcutaneous tumours in vivo with simultaneous MR thermometry.

CONCLUSIONS

A platform for small-animal hyperthermia investigations under ultra-high-field MR thermometry was developed and applied to heating subcutaneous tumours in vivo.

Abstract 4820: Developing a xenograft human tumor model in immunocompetent mice

Animal models are essential to preclinical cancer research and are used clinically to determine optimal treatment regimens, but current xenograft models are limited in their utility, especially due to the lack of a competent immune system. Here we demonstrate that a xenograft tumor model can be developed in immunocompetent mice by tolerizing murine fetuses to human tumor cells. A375 human melanoma cells were injected into day E14 fetuses and, after birth, mice were challenged again with A375 cells to determine their ability to develop tumors. Intravenous injections of A375 cells after tolerization resulted in metastatic-like lung tumors, which were verified to be human in origin by immunohistochemistry and PCR. The development of lung neoplasms was dependent on fetal tolerization; non-tolerized mice did not develop tumors after injection. Interestingly, subcutaneous injected cells did not form tumors, but this was shown to be due to an innate, non-adaptive immune response and did not create lasting rejection of tumor cells. This procedure was repeated with several different tumor lines to show the universal nature of the method: BxPC3 (human pancreatic cancer), M21 (human melanoma), HeLa (human cervical cancer), and MDA231 (human breast carcinoma).

Citation Format: Matthew T. Basel, Sanjeev Narayanan, Chanran Ganta, Tej B. Shrestha, Marla Pyle, Stefan H. Bossmann, Deryl L. Troyer. Developing a xenograft human tumor model in immunocompetent mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4820. doi:10.1158/1538-7445.AM2017-4820

Abstract 1613: Genetically modified neuronal stem cells expressing IL-12 and TNFSF14 attenuate highly metastatic mammary tumors in a mouse model

Interleukin 12 (IL-12) is a heterodimeric cytokine encoded by two genes, p35 and p40. IL-12, also known as T cell-stimulating factor, induces proliferation of T-lymphocytes and natural killer (NK) cells, while also demonstrating an anti-angiogenic effect and inhibition of regulatory T cells. Similarly, LIGHT (TNFSF14) is a transmembrane protein which acts as a costimulatory factor for the activation lymphoid cells and stimulates the proliferation of T cells, leading to increased apoptosis of tumor cells. Expression of IL-12 and LIGHT specifically in the tumor region could activate T cells and stimulate the immune system to attenuate the tumor. Tumor homing neuronal stem cells C17.2 (NSC) were genetically engineered to express the mouse-LIGHT gene and IL-12 using a retrovirus. The expression of LIGHT and IL-12 genes in NSC was confirmed by PCR, ELISA and Western blot. To test the antitumor effects of the engineered cells, Balb/C mice bearing 4T1 mammary tumors were treated with NSC-LIGHT, NSC-IL-12 and NSC-LIGHT/IL-12 cells intratumorally (I.T.) at day nine. Repeated tumor measurement over time showed attenuation of mammary tumor growth in the both NSC/IL-12 and NSC/LIGHT groups in comparison with control groups PBS and NSC. Tumor growth was further reduced by treating the mice with NSC expressing both cytokines LIGHT and IL-12. Tumor metastasis was also evaluated by removing the primary tumor surgically and observing mice for any sign of metastatic burden. Treatment groups had less metastatic tumor burden and survived longer than the control group. Therefore, tumor homing NPC-LIGHT/IL-12 cells could be effective for the treatment of highly metastatic mammary tumors.

Citation Format: Tej B. Shrestha, Dezhang Lu, Matthew T. Basel, Marla Pyle, Stefan H. Bossmann, Deryl L. Troyer. Genetically modified neuronal stem cells expressing IL-12 and TNFSF14 attenuate highly metastatic mammary tumors in a mouse model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1613. doi:10.1158/1538-7445.AM2017-1613

New Results from the Search for Low-Mass Weakly Interacting Massive Particles with the CDMS Low Ionization Threshold Experiment

The CDMS low ionization threshold experiment (CDMSlite) uses cryogenic germanium detectors operated at a relatively high bias voltage to amplify the phonon signal in the search for weakly interacting massive particles (WIMPs). Results are presented from the second CDMSlite run with an exposure of 70 kg day, which reached an energy threshold for electron recoils as low as 56 eV. A fiducialization cut reduces backgrounds below those previously reported by CDMSlite. New parameter space for the WIMP-nucleon spin-independent cross section is excluded for WIMP masses between 1.6 and 5.5  GeV/c^{2}.

Human umbilical cord matrix mesenchymal stem cells suppress the growth of breast cancer by expression of tumor suppressor genes

Human and rat umbilical cord matrix mesenchymal stem cells (UCMSC) possess the ability to control the growth of breast carcinoma cells. Comparative analyses of two types of UCMSC suggest that rat UCMSC-dependent growth regulation is significantly stronger than that of human UCMSC. Their different tumoricidal abilities were clarified by analyzing gene expression profiles in the two types of UCMSC. Microarray analysis revealed differential gene expression between untreated naïve UCMSC and those co-cultured with species-matched breast carcinoma cells. The analyses screened 17 differentially expressed genes that are commonly detected in both human and rat UCMSC. The comparison between the two sets of gene expression profiles identified two tumor suppressor genes, adipose-differentiation related protein (ADRP) and follistatin (FST), that were specifically up-regulated in rat UCMSC, but down-regulated in human UCMSC when they were co-cultured with the corresponding species' breast carcinoma cells. Over-expression of FST, but not ADRP, in human UCMSC enhanced their ability to suppress the growth of MDA-231 cells. The growth of MDA-231 cells was also significantly lower when they were cultured in medium conditioned with FST, but not ADRP over-expressing human UCMSC. In the breast carcinoma lung metastasis model generated with MDA-231 cells, systemic treatment with FST-over-expressing human UCMSC significantly attenuated the tumor burden. These results suggest that FST may play an important role in exhibiting stronger tumoricidal ability in rat UCMSC than human UCMSC and also implies that human UCMSC can be transformed into stronger tumoricidal cells by enhancing tumor suppressor gene expression.

First direct limits on lightly ionizing particles with electric charge less than e/6

While the standard model of particle physics does not include free particles with fractional charge, experimental searches have not ruled out their existence. We report results from the Cryogenic Dark Matter Search (CDMS II) experiment that give the first direct-detection limits for cosmogenically produced relativistic particles with electric charge lower than e/6. A search for tracks in the six stacked detectors of each of two of the CDMS II towers finds no candidates, thereby excluding new parameter space for particles with electric charges between e/6 and e/200.

Hexagonal magnetite nanoprisms: preparation, characterization and cellular uptake

Nearly perfect hexagonal Fe₃O₄ nanoplatelet structures, with edge length of 45 ± 5 nm and thickness of 5 to 6 nm were synthesized from iron(iii) acetylacetonate using the dual ligand system oleic and stearic acid.

Abstract 4920: Luminol-based in situ photodynamic therapy for breast adenocarcinoma

Photodynamic therapy (PDT) is a cancer treatment that uses a photosensitizer and a specific wavelength of light. When tumor cells which have absorbed photosensitizer are exposed to the correct wavelength of light, reactive oxygen species are generated, resulting in tumor cell death. Poor tissue penetration of light is a major limitation in PDT, restricting its use to treatment of localized tumors. Light generation at the tumor area might increase the effectiveness of PDT and can expand its use for metastatic tumors. Infiltration of tumor-activated polymorphonuclear neutrophils (PMNs) produces luminescence in the presence of luminol; this bioluminescence has been used for tumor detection in pre-clinical trials. Based on this rationale, we hypothesized that luminol-based bioluminescence can cause targeted PDT in breast adenocarcinoma tumors in the presence of the photosensitizer 5-aminolevulinic acid (ALA). To test this hypothesis, BALB/c mice were transplanted with 4T1 mammary adenocarcinoma cells to establish a breast adenocarcinoma model. After tumor formation, ALA and luminol were administered to mice through intraperitoneal and intravenous routes, respectively. This treatment regimen was repeated six times and ALA alone/luminol alone/saline treated tumor-bearing mice were used as controls. Relative differences in the increase of tumor volume and final tumor weights were analyzed to test the treatment hypothesis. Analysis of the data showed that treatment with a combination of luminol and ALA as well as treatment with luminol alone results in breast adenocarcinoma tumor growth attenuation. This study gives evidence for the antitumor activity of luminol on breast adenocarcinoma, possibly through PDT.

Citation Format: Hamad S. Alshetaiwi, Tej B. Shrestha, Sivasai Balivada, Matthew T. Basel, Marla Pyle, Hongwang Wang, Stefan H. Bossmann, Deryl L. Troyer. Luminol-based in situ photodynamic therapy for breast adenocarcinoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4920. doi:10.1158/1538-7445.AM2014-4920

Search for low-mass weakly interacting massive particles with SuperCDMS

We report a first search for weakly interacting massive particles (WIMPs) using the background rejection capabilities of SuperCDMS. An exposure of 577 kg days was analyzed for WIMPs with mass <30  GeV/c(2), with the signal region blinded. Eleven events were observed after unblinding. We set an upper limit on the spin-independent WIMP-nucleon cross section of 1.2×10(-42)  cm(2) at 8  GeV/c(2). This result is in tension with WIMP interpretations of recent experiments and probes new parameter space for WIMP-nucleon scattering for WIMP masses <6  GeV/c(2).

Search for low-mass weakly interacting massive particles using voltage-assisted calorimetric ionization detection in the SuperCDMS experiment

SuperCDMS is an experiment designed to directly detect weakly interacting massive particles (WIMPs), a favored candidate for dark matter ubiquitous in the Universe. In this Letter, we present WIMP-search results using a calorimetric technique we call CDMSlite, which relies on voltage-assisted Luke-Neganov amplification of the ionization energy deposited by particle interactions. The data were collected with a single 0.6 kg germanium detector running for ten live days at the Soudan Underground Laboratory. A low energy threshold of 170  eVee (electron equivalent) was obtained, which allows us to constrain new WIMP-nucleon spin-independent parameter space for WIMP masses below 6  GeV/c2.

Silicon detector dark matter results from the final exposure of CDMS II

We report results of a search for weakly interacting massive particles (WIMPS) with the silicon detectors of the CDMS II experiment. This blind analysis of 140.2 kg day of data taken between July 2007 and September 2008 revealed three WIMP-candidate events with a surface-event background estimate of 0.41(-0.08)(+0.20)(stat)(-0.24)(+0.28)(syst). Other known backgrounds from neutrons and 206Pb are limited to <0.13 and <0.08 events at the 90% confidence level, respectively. The exposure of this analysis is equivalent to 23.4 kg day for a recoil energy range of 7-100 keV for a WIMP of mass 10  GeV/c2. The probability that the known backgrounds would produce three or more events in the signal region is 5.4%. A profile likelihood ratio test of the three events that includes the measured recoil energies gives a 0.19% probability for the known-background-only hypothesis when tested against the alternative WIMP+background hypothesis. The highest likelihood occurs for a WIMP mass of 8.6  GeV/c2 and WIMP-nucleon cross section of 1.9×10(-41)  cm2.

Luminol-based bioluminescence imaging of mouse mammary tumors

Polymorphonuclear neutrophils (PMNs) are the most abundant circulating blood leukocytes. They are part of the innate immune system and provide a first line of defense by migrating toward areas of inflammation in response to chemical signals released from the site. Some solid tumors, such as breast cancer, also cause recruitment and activation of PMNs and release of myeloperoxidase. In this study, we demonstrate that administration of luminol to mice that have been transplanted with 4T1 mammary tumor cells permits the detection of myeloperoxidase activity, and consequently, the location of the tumor. Luminol allowed detection of activated PMNs only two days after cancer cell transplantation, even though tumors were not yet palpable. In conclusion, luminol-bioluminescence imaging (BLI) can provide a pathway towards detection of solid tumors at an early stage in preclinical tumor models.

Abstract 220: Human umbilical cord matrix-derived stem cells control tumor growth by tumor suppressor gene expression

Umbilical cord matrix derived stem cells (UCMSC) have the potential to treat various diseases including cancer. We have shown that naïve human and rat UCMSC significantly attenuate proliferation of multiple cancer cells (Ganta et al., Cancer Res., 2009. Ayuzawa et al., Cancer Lett., 2009). However, the growth attenuation ability of rat UCMSC is stronger than that of human UCMSC. To clarify their different tumoricidal abilities, differential gene expression profiles of these two cells were studied by micro-array analysis using Illumina HumanRef-8 V2 for human and RatRef-12 BeadChip for rat UCMSC. The gene expression profiles were compared between UCMSC untreated and co-cultured with either human (MDA-231) or rat breast carcinoma cells (Mat B III). Selection criteria used for the screening of candidate genes associated with UCMSC-dependent tumoricidal ability are as follows; 1) gene expression difference should be at least a 1.5 fold between naive UCMSC and those co-cultured with mammary tumor cells; 2) they must encode secretory proteins; and 3) they must encode cell growth regulation-related proteins. These analyses screened 16 common genes from both human and rat UCMSC. The comparison between two sets of gene expression profiles identified that two genes, adipose-differentiation related protein (ADRP) and follistatin (FST), were specifically up-regulated in rat UCMSC, whereas they were down-regulated in human UCMSC when they were co-cultured with the corresponding species’ breast cancer cells. The suppression of either protein by adding specific neutralizing antibody in culture of rat UCMSC significantly abrogated their ability to attenuate cell growth. Over-expression of both genes by adenovirus vector in human UCMSC enhanced their ability to suppress the growth of MDA-231 cells. FST over-expression in MDA 231 cells also decreased their growth significantly. In the experimental lung metastasis model with MDA 231 cells in immunodeficient mice, the treatment with FST-over-expressing human UCMSC was administered three times, at one week intervals, via tail vein injection, starting 6 days after tumor cell inoculation. Examination 4 weeks after tumor inoculation showed a significant decrease in the number of tumor nodules in the lungs. Both ADRP and FST are considered to be tumor suppressor genes. These results suggest that both ADRP and FST may play important roles in exhibiting a stronger tumoricidal ability in rat UCMSC than human UCMSC. These results imply that human UCMSC can be transformed into stronger tumoricidal cells by enhancing tumor suppressor gene expression. This work was supported by the Kansas State University (KSU) Terry C. Johnson Center for Basic Cancer Research, KSU College of Veterinary Medicine Dean's Fund, NIH RR017686, RR15563, CA135599, Kansas Bioscience Authority research grant.

Citation Format: Naomi Ohta, Susumu Ishiguro, Atsushi Kawabata, Deepthi Uppalapati, Marla Pyle, Deryl Troyer, Supriyo De, Yongqing Zhang, Kevin G. Becker, Masaaki Tamura. Human umbilical cord matrix-derived stem cells control tumor growth by tumor suppressor gene expression. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 220. doi:10.1158/1538-7445.AM2013-220

Abstract 1558: Imaging of metastatic B16F10 melanoma in mice using tumor-homing stem cells

Tumors, like wounds, recruit cells from surrounding tissues and bone marrow. Some of these cells provide support and nutrition, while others participate in an inflammatory response. Bone marrow mesenchymal stem cells (MSCs) exhibit this tropism toward wounds and other areas of pathology. Consequently, stem cell technology for diagnostic and therapeutic purposes is an emerging field in cancer biology. Like bone marrow MSCs, mouse neural progenitor cells (NPCs) tend to migrate toward cancer sites. We found that these cells migrate toward B16F10 lung melanomas, making them very good candidates for delivery of chemotherapeutic drugs, genes of interest, and imaging contrast agents. Among imaging techniques, bioluminescent imaging is non-invasive. Gaussia luciferase (Gluc) is particularly useful, as it is non-toxic and has stronger luminescence than other known luciferases. In the presence of its substrate coelenterazine (coel), Gluc luminescence peaks near 470 nm. In this study, we engineered NPCs to secrete Gluc. These Gluc-engineered cells were injected systemically to C57BL/6 mice bearing metastatic B16F10 lung melanoma and mice were given coel intravenously. Imaging of the mice on the Caliper IVIS Lumina II showed bioluminescence in disseminated areas. The distribution of bioluminescence suggested that the engineered NPCs migrated to the tumor sites and secreted Gluc. In confirmation, necropsy revealed black metastatic tumors in the locations emitting bioluminescence. Although IV injection of metastatic B16F10 lung melanoma cells usually generates lung tumors, we found dissemination of melanoma in other parts of the body. The Gluc-expressing NPCs could find the tumors as early as 2 days post tumor-cell injection, long before tumors were palpable. Thus, this system offers promise for improving cancer diagnosis. For improved imaging, this bioluminescence system can be coupled with other fluorescent dyes for red shifted output. Finally, the same sensitivity and tumor tropism suggests that the NPCs could be useful delivery cells for tumor-targeted therapeutics.

Citation Format: Tej B. Shrestha, Sivasai Balivada, Matthew Basel, Marla Pyle, Stefan H. Bossmann, Deryl L. Troyer. Imaging of metastatic B16F10 melanoma in mice using tumor-homing stem cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1558. doi:10.1158/1538-7445.AM2013-1558

Abstract LB-116: Immunodeficient pigs as a large animal model for human tumors

Currently, SCID mice are the major biomedical model for the study of human cancer and other diseases; however, they can be a poor model because there is a large discrepancy in body size and physiology between rodents and humans. Since most new anticancer drugs are first evaluated in rodents, most fail in phase I and phase II clinical trials. Thus, there is a tremendous demand for more sophisticated animal models, which may improve the translation efficiency from preclinical to clinical studies. We recently identified pigs that are severely immunocompromised. Here we tested these pigs as a model for human tumors. Three immunodeficient (ID) pigs and three normal (WT) pigs, six weeks of age, were tested for their ability to allow xenotransplanted human tumors to grow. Each pig was transplanted with 4 million A375 human malignant melanoma cells subcutaneously into the left ear and 4 million PANC-1 human pancreatic carcinoma cells subcutaneously into the right ear on day 0. The ID pigs were euthanized 6, 14, or 23 days after cell transplantation, based on their health condition. Palpable melanoma tumors were identified on day 13 after cell transplantation in the two remaining ID pigs. After euthanasia, full necropsy was performed on all pigs; tissues were collected from ears and other organs for histopathological analysis. Melanoma and pancreatic tumor xenotransplants were identified histologically in all three ID pigs. The presence of human cancer cells in these pigs was further verified with anti-human mitochondrial immunohistochemistry. No transplanted tumors were found, grossly, histologically, or immunohistochemically, in the WT pigs. We propose that this genetic line of ID pigs may prove to be a useful large animal model for human tumors.

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 LB-116. doi:1538-7445.AM2012-LB-116

Interleukin-1β and transforming growth factor-β cooperate to induce neurosphere formation and increase tumorigenicity of adherent LN-229 glioma cells

INTRODUCTION

Glioma stem cells (GSCs) have the property of self-renewal and appear to be a driving force for the initiation and recurrence of gliomas. We recently found that the human tumorigenic LN-229 glioma cell line failed to form neurospheres in serum-free conditions and generated mostly small tumors in vivo, suggesting that either LN-229 GSCs are not active in these conditions or GSCs are absent in the LN-229 cell line.

METHODS

Using self-renewal assay, soft-agar colony assay, cell proliferation assay, invasion assay, real time PCR analysis, ELISA and in vivo tumorigenic assay, we investigated the effects of interleukin (IL)-1β and transforming growth factor (TGF)-β on the development of GSCs from LN-229 cells.

RESULTS

Here, we demonstrate that the combination of IL-1β and TGF-β can induce LN-229 cells to form neurospheres in serum-free medium. IL-1β/TGF-β-induced neurospheres display up-regulated expression of stemness factor genes (nestin, Bmi-1, Notch-2 and LIF), and increased invasiveness, drug resistance and tumor growth in vivo: hallmarks of GSCs. These results indicate that IL-1β and TGF-β cooperate to induce a GSC phenotype in the LN-229 cell line. Induction of nestin, LIF and Notch-2 by IL-1β/TGF-β can be reverted after cytokine withdrawal. Remarkably, however, up-regulated Bmi-1 levels remained unchanged after cytokine withdrawal; and the cytokine-withdrawn cells maintained strong clonogenicity, suggesting that Bmi-1 may play a crucial role in tumorigenesis.

CONCLUSIONS

Our finding indicates that glioma cells without self-renewal capability in standard conditions could also contribute to glioma malignancy when cytokines, such as IL-1β and TGF-β, are present in the tumor environment. Targeting GSC-promoting cytokines that are highly expressed in glioblastomas may contribute to the development of more effective glioma therapies.

Cell-delivered magnetic nanoparticles caused hyperthermia-mediated increased survival in a murine pancreatic cancer model

Using magnetic nanoparticles to absorb alternating magnetic field energy as a method of generating localized hyperthermia has been shown to be a potential cancer treatment. This report demonstrates a system that uses tumor homing cells to actively carry iron/iron oxide nanoparticles into tumor tissue for alternating magnetic field treatment. Paramagnetic iron/ iron oxide nanoparticles were synthesized and loaded into RAW264.7 cells (mouse monocyte/ macrophage-like cells), which have been shown to be tumor homing cells. A murine model of disseminated peritoneal pancreatic cancer was then generated by intraperitoneal injection of Pan02 cells. After tumor development, monocyte/macrophage-like cells loaded with iron/ iron oxide nanoparticles were injected intraperitoneally and allowed to migrate into the tumor. Three days after injection, mice were exposed to an alternating magnetic field for 20 minutes to cause the cell-delivered nanoparticles to generate heat. This treatment regimen was repeated three times. A survival study demonstrated that this system can significantly increase survival in a murine pancreatic cancer model, with an average post-tumor insertion life expectancy increase of 31%. This system has the potential to become a useful method for specifically and actively delivering nanoparticles for local hyperthermia treatment of cancer.

Cell-delivered magnetic nanoparticles caused hyperthermia-mediated increased survival in a murine pancreatic cancer model

Using magnetic nanoparticles to absorb alternating magnetic field energy as a method of generating localized hyperthermia has been shown to be a potential cancer treatment. This report demonstrates a system that uses tumor homing cells to actively carry iron/iron oxide nanoparticles into tumor tissue for alternating magnetic field treatment. Paramagnetic iron/ iron oxide nanoparticles were synthesized and loaded into RAW264.7 cells (mouse monocyte/ macrophage-like cells), which have been shown to be tumor homing cells. A murine model of disseminated peritoneal pancreatic cancer was then generated by intraperitoneal injection of Pan02 cells. After tumor development, monocyte/macrophage-like cells loaded with iron/ iron oxide nanoparticles were injected intraperitoneally and allowed to migrate into the tumor. Three days after injection, mice were exposed to an alternating magnetic field for 20 minutes to cause the cell-delivered nanoparticles to generate heat. This treatment regimen was repeated three times. A survival study demonstrated that this system can significantly increase survival in a murine pancreatic cancer model, with an average post-tumor insertion life expectancy increase of 31%. This system has the potential to become a useful method for specifically and actively delivering nanoparticles for local hyperthermia treatment of cancer.

Abstract B46: Umbilical cord matrix-derived stem cells control tumor growth by their tumor suppressor and promoter gene expression

Umbilical cord matrix-derived stem cells (UCMSC) have the potential to treat various diseases including cancer. We have shown that naïve human and rat UCMSC significantly attenuate proliferation of multiple cancer cells. However, our previous study showed that the growth attenuation ability of rat UCMSC is stronger than that of human UCMSC. To clarify their different tumoricidal abilities, differential gene expression profiles were studied by microarray analysis using IIIumina HumanRef-8 V2 BeadChip for human and RatRef-12 BeadChip for rat UCMSC. The differential gene expression profile between untreated human UCMSC and those co-cultured with MDA-MB 231 human breast carcinoma cells was compared with that between untreated rat UCMSC and those co-cultured with Mat B III rat mammary gland carcinoma cells. Strict screening criteria used to identify putative genes associated with UCMSC-dependent tumoricidal activity were as follows: gene expression should (1) be over than 1.5 fold different, (2) encode secretory proteins, and (3) be associated with cell growth regulation. Seventeen genes were identified as being associated with either human or rat UCMSC-dependent tumor growth regulation. Among these genes, eight were up-regulated in both human and rat UCMSC (two being known tumor suppressor and six being putative tumor promoter genes). Seven out of seventeen genes were up-regulated in human UCMSC but not in rat UCMSC (three were identified to be tumor suppressor and four were tumor promoter genes). Two out of the seventeen genes, adipose-differentiation related protein (ADRP) and follistatin (FST), which are known tumor suppressor genes, were specifically up-regulated in rat UCMSC, whereas they were down-regulated in human UCMSC when they were co-cultured with carcinoma cells. These results strongly suggest that the balance of the up-regulation of tumor suppressor genes and down-regulation of tumor promoter genes in UCMSC appear to control tumor growth. Since both ADRP and FST are considered to be tumor suppressor genes and were specifically up-regulated in only rat UCMSC, these two genes expression may play central role in strong tumoricidal activity by rat UCMSC. In support of this hypothesis, suppression of ADRP and FST protein by adding a neutralizing antibody (4 µg/ml) in culture medium of rat UCMSC significantly abrogated their ability to attenuate DNA synthesis. Over-expression of ADRP and FST genes by adenoviral vector (100 MOI) in human UCMSC promoted their ability to suppress the DNA synthesis of MDA-MB 231 cells in [3H]-thymidine uptake assay. Interestingly, ADRP expression in human UCMSC stimulated differentiation to adipose type cell morphology (cell enlargement and oil droplet accumulations in cytoplasm). This result suggests that ADRP may stimulate adiponectin production in vivo thereby attenuating tumor growth. Taken together, these results suggest that both ADRP and FST may be key genes that exhibit stronger tumoricidal ability in rat UCMSC than human UCMSC. This work was supported by the Kansas State University (KSU) Terry C. Johnson Center for Basic Cancer Research, KSU College of Veterinary Medicine Dean's Fund, NIH RR017686, RR15563, CA135599, Kansas Bioscience Authority Collaborative Cancer Research grant and by the Intramural Research Program of the NIH, National Institute on Aging.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the Second AACR International Conference on Frontiers in Basic Cancer Research; 2011 Sep 14-18; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2011;71(18 Suppl):Abstract nr B46.

A self-contained enzyme activating prodrug cytotherapy for preclinical melanoma

Gene-directed enzyme prodrug therapy (GDEPT) has been investigated as a means of cancer treatment without affecting normal tissues. This system is based on the delivery of a suicide gene, a gene encoding an enzyme which is able to convert its substrate from non-toxic prodrug to cytotoxin. In this experiment, we have developed a targeted suicide gene therapeutic system that is completely contained within tumor-tropic cells and have tested this system for melanoma therapy in a preclinical model. First, we established double stable RAW264.7 monocyte/macrophage-like cells (Mo/Ma) containing a Tet-On® Advanced system for intracellular carboxylesterase (InCE) expression. Second, we loaded a prodrug into the delivery cells, double stable Mo/Ma. Third, we activated the enzyme system to convert the prodrug, irinotecan, to the cytotoxin, SN-38. Our double stable Mo/Ma homed to the lung melanomas after 1 day and successfully delivered the prodrug-activating enzyme/prodrug package to the tumors. We observed that our system significantly reduced tumor weights and numbers as targeted tumor therapy after activation of the InCE. Therefore, we propose that this system may be a useful targeted melanoma therapy system for pulmonary metastatic tumors with minimal side effects, particularly if it is combined with other treatments.

Non-random tissue distribution of human naïve umbilical cord matrix stem cells

AIM

To determine the tissue and temporal distribution of human umbilical cord matrix stem (hUCMS) cells in severe combined immunodeficiency (SCID) mice.

METHODS

For studying the localization of hUCMS cells, tritiated thymidine-labeled hUCMS cells were injected in SCID mice and tissue distribution was quantitatively determined using a liquid scintillation counter at days 1, 3, 7 and 14. Furthermore, an immunofluorescence detection technique was employed in which anti-human mitochondrial antibody was used to identify hUCMS cells in mouse tissues. In order to visualize the distribution of transplanted hUCMS cells in H&E stained tissue sections, India Black ink 4415 was used to label the hUCMS cells.

RESULTS

When tritiated thymidine-labeled hUCMS cells were injected systemically (iv) in female SCID mice, the lung was the major site of accumulation at 24 h after transplantation. With time, the cells migrated to other tissues, and on day three, the spleen, stomach, and small and large intestines were the major accumulation sites. On day seven, a relatively large amount of radioactivity was detected in the adrenal gland, uterus, spleen, lung, and digestive tract. In addition, labeled cells had crossed the blood brain barrier by day 1.

CONCLUSION

These results indicate that peripherally injected hUCMS cells distribute quantitatively in a tissue-specific manner throughout the body.

Abstract LB-199: SN38-dextran prodrug synthesis and cell delivery in a murine metastatic pancreatic cancer model

Enzyme activated prodrugs have been investigated and sought after as highly-specific, low side effect treatments, especially for cancer therapy. We synthesized an SN38-dextran prodrug and utilized it in a cell delivery system that can carry both the prodrug and an activating enzyme to the cancer site. For delivery of our prodrug, we engineered Raw264.7 cells (mouse monocyte/macrophage like cells, Mo/Ma) to express intracellular rabbit carboxylesterase (InCE), which cleaves the prodrug to activate SN38. InCE expression was regulated by the TetOn® system, which silences the gene unless a tetracycline, such as doxycycline is present. To test the system, a murine pancreatic cancer model was generated by intraperitoneal (i.p.) injection of Pan02 cells. Engineered Mo/Ma cells were loaded with the SN38-dextran prodrug and were injected i.p. into the mice. Two days following injection, doxycycline was given i.p. to activate the InCE, which in turn activates the prodrug into active SN38. A survival study demonstrated that this system significantly increased survival in a murine pancreatic cancer model, with an average post-diagnosis life expectancy increase of 20%. Thus, for the first time, a prodrug/activating enzyme system self-contained within tumor-homing cells has been demonstrated that can significantly prolong the life of i.p. pancreatic tumor bearing mice.

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 LB-199. doi:10.1158/1538-7445.AM2011-LB-199

Abstract 3348: Naïve rat umbilical cord matrix stem cells abrogate mammary tumor growth through markedly enhanced tumor immune responses

Mesenchymal stem cells derived from the umbilical cord matrix (UCMSC) have great potential for therapeutic use in multiple diseases including cancer. We have demonstrated that un-engineered naïve human and rat UCMSC attenuate growth of several organ type tumors (Ayuzawa et al., Cancer Lett.2009; Ganta et al., Cancer Res, 2009, Doi et al., Cytotherapy 2010). Since UCMSC are easy to prepare in relatively large quantities and are poorly immunogenic in allogeneic transplantation, they are potentially useful in cancer therapy. However, the mechanism by which UCMSC attenuate tumor growth has not been studied rigorously. Hence, the objectives of this study were to examine the ability of UCMSC to control the growth of mammary tumors and to determine possible mechanisms by which UCMSC attenuate the tumor growth. Intratumoral injection of rat UCMSC markedly attenuated tumor growth of orthotopic Mat B III autografts in female F344 rat mammary gland. Histopathology of the tumors in the rat UCMSC group indicated that a large number of lymphocytes had infiltrated into the peritumoral area and were occasionally observed in the intratumoral area. Immunohistochemistry revealed that although CD3+ T lymphocytes were located mainly in the peritumoral area rather than in the intratumoral area, CD20+ cells were rarely seen suggesting that the majority of infiltrated lymphocytes in the rat UCMSC treated tumors were T cells. In addition, the treatment of rat UCMSC increased the CD 8+ cell infiltration throughout tumor tissue. CD68+ cells were scarcely observed in the tumors of the PBS control group but not in the rat UCMSC treated group. Transwell culture system-based in vitro migration assay revealed that rat UCMSC significantly enhanced migration of peripheral blood mononuclear cells. These results suggest that naïve rat UCMSC attenuated mammary tumor growth at least in part by markedly enhanced host immune responses against tumors. This research demonstrates that naïve rat UCMSC can be used as powerful anti-cancer therapeutic cells for breast cancer treatment. This work was supported by the Kansas State University (KSU) Terry C. Johnson Center for Basic Cancer Research, KSU CVM Dean's Fund, NIH P20 RR017686, p20 RR1556, R21CA135599 and Kansas Bioscience Authority research fund.

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 3348. doi:10.1158/1538-7445.AM2011-3348

Abstract 3355: Identification of unique tumoricidal genes in rat umbilical cord matrix stem cells

Umbilical cord matrix stem cells (UCMSC) represent a promising source of therapeutics for various diseases including cancer. We have shown that naïve rat UCMSC significantly attenuate Fisher 344 rat-derived mammary adenocarcinoma (Mat B III) cell proliferation both in vivo and in vitro. To study the underlying mechanisms and genes involved in the Mat B III growth attenuation, we investigated gene expression profiles of naive rat UCMSC alone co-cultured with Mat BIII cells by cDNA microarray analysis. Total RNA was extracted from the naïve rat UCMSC alone and those co-cultured with Mat B III in transwell culture dishes. The comparison of gene expression profiles between untreated and co-cultured rat UCMSC identified five up-regulated (Follistatin (FST), Sulfatase1 (SULF-1), Glucose phosphate isomerase (GPI), HtrA serine peptidase (HTRA1), and Adipocyte differentiation-related protein (ADRP)) and two down-regulated (Transforming growth factor, beta-induced (TGFBI), Podoplanin (PDPN)) candidate genes based upon the following screening criteria: 1) candidate gene expression should show at least a 1.5 fold change in rat UCMSC co-cultured with Mat B III cells; 2) candidate genes encode secretory proteins; and 3) candidate genes encode cell growth-related proteins. Following confirmation of gene expression by real time-PCR, ADRP, SULF-1 and GPI were selected for further analysis. Addition of specific neutralizing antibodies against these three gene products individually or all together in the co-culture of Mat B III cells and 1/20 cell number of rat UCMSC significantly increased [3H] thymidine uptake in the Mat B III cells implying that these gene products are functionally produced under the co-cultured condition and attenuate cell growth. Immunoprecipitation followed by Western Blot analysis demonstrated that these proteins are indeed secreted into the culture medium. We are investigating the siRNA-dependent down regulation of these genes in rat UCMSC to confirm their tumor suppressor function. These results suggest that ADRP, SULF-1 and GPI act as tumor suppressor genes and these genes might be involved in rat UCMSC-dependent growth attenuation of rat mammary tumor. This work was supported by the Kansas State University (KSU) Terry C. Johnson Center for Basic Cancer Research, KSU College of Veterinary Medicine Dean's Fund, NIH P20 RR017686, p20RR1556, R21CA135599, Kansas Bioscience Authority research fund and by the Intramural Research Program of the NIH, National Institute on Aging.

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 3355. doi:10.1158/1538-7445.AM2011-3355

Abstract LB-98: Reprogramming towards glioma stem-like cells by cytokines

Gliomas are the most common primary brain tumor in adults and are very aggressive, invasive and destructive malignancies. Recent studies suggest that glioma stem cells (GSCs) are responsible for the initiation, recurrence of gliomas, and resistance to radiological and chemotherapies, indicating that targeting GSCs is a more effective therapeutic strategy against gliomas. However, it is still unclear about the molecular mechanisms that govern GSC biology. TGF-beta and IL-1beta are both highly active in high grade gliomas and their elevated activities have been associated with poor prognosis in glioma patients. The link between TGF-beta and IL-1beta and malignant phenotype of gliomas suggests that TGF-beta and IL-1beta may contribute to glioma stem cell development. To test the hypothesis, we explored human glioma cell line LN229 and the serum-free condition. The serum-free condition supplemented with epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) has been commonly used to identify GSCs, which readily form spheres, called "glioma spheres". However, LN229 cells cannot form spheres in serum-free medium, suggesting that these cells contain very few stem cells. We found that addition of IL-1beta and TGF-beta, but not either cytokine alone, to the serum-free medium resulted in sphere formation of LN229 cells even at clonal density, indicating that the two cytokines act in a synergistic fashion to induce self-renewal. Immunocytochemical analysis demonstrated that most IL-1beta/TGF-beta-induced sphere cells were nestin-positive cells. In addition, quantative PCR analyses showed that the induced spheres had significantly increased expression of other stemness markers including LIF, Notch-2 and Bmi-1. To further validate the self-renewal of the induced spheres, sphere cells were dissociated and plated in the absence of the cytokines in soft agar. The sphere cells formed more and larger colonies than the control cells by about two fold in number and size. Furthermore, the induced sphere cells demonstrated significantly increased invasion and drug resistance. Meanwhile, the gene expression of invasion-related genes including SIP1, beta-integrin and N-cadherin were also highly increased in the induced spheres compared to the control. More importantly, the induced sphere cells demonstrated their oncogenic potential by forming larger tumor with less number of cells in the brain of immunocompromised mice than the control cells. Overall, these results indicate that the spheres induced by IL-1beta and TGF-beta are cancer stem-like cells with the properties of self-renewal, drug resistance, invasion and oncogenic potential. Our finding suggests that GSCs can be a dynamic stage and microenvironmental conditions can promote the acquisition of a stem cell-like state from differentiated cells.

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 LB-98. doi:10.1158/1538-7445.AM2011-LB-98

Results from a low-energy analysis of the CDMS II germanium data

We report results from a reanalysis of data from the Cryogenic Dark Matter Search (CDMS II) experiment at the Soudan Underground Laboratory. Data taken between October 2006 and September 2008 using eight germanium detectors are reanalyzed with a lowered, 2 keV recoil-energy threshold, to give increased sensitivity to interactions from weakly interacting massive particles (WIMPs) with masses below ∼10  GeV/c(2). This analysis provides stronger constraints than previous CDMS II results for WIMP masses below 9  GeV/c(2) and excludes parameter space associated with possible low-mass WIMP signals from the DAMA/LIBRA and CoGeNT experiments.

Attenuation of mouse melanoma by A/C magnetic field after delivery of bi-magnetic nanoparticles by neural progenitor cells

Localized magnetic hyperthermia as a treatment modality for cancer has generated renewed interest, particularly if it can be targeted to the tumor site. We examined whether tumor-tropic neural progenitor cells (NPCs) could be utilized as cell delivery vehicles for achieving preferential accumulation of core/shell iron/iron oxide magnetic nanoparticles (MNPs) within a mouse model of melanoma. We developed aminosiloxane-porphyrin functionalized MNPs, evaluated cell viability and loading efficiency, and transplanted neural progenitor cells loaded with this cargo into mice with melanoma. NPCs were efficiently loaded with core/shell Fe/Fe(3)O(4) MNPs with minimal cytotoxicity; the MNPs accumulated as aggregates in the cytosol. The NPCs loaded with MNPs could travel to subcutaneous melanomas, and after A/C (alternating current) magnetic field (AMF) exposure, the targeted delivery of MNPs by the cells resulted in a measurable regression of the tumors. The tumor attenuation was significant (p < 0.05) a short time (24 h) after the last of three AMF exposures.

Abstract 3336: Upregulated inflammatory cytokines in glioma stem cells: Targets for glioma therapies

Gliomas are the most common primary brain tumors in adults. With the highly invasive growth pattern, gliomas often escape current therapeutic modalities including combinations of surgery, radiotherapy and chemotherapy. Recent studies implicate that a minority population of glioma stem cells (GSCs) are responsible for glioma maintenance and recurrence. Interleukin (IL)-1 beta, IL-6 and IL-8 are pleiotropic proinflammatory cytokines and their excessive production in the tumor microenvironment is associated with poor disease outcome in many cancer types, including glioma. These cytokines promote tumor growth via induction of proteins associated with tumor invasion and angiogenesis and anti-apoptosis. We hypothesize that GSCs acquire their chemo-resistance and invasion by excessive cytokine production. To test the hypothesis, we compared the cytokine gene expression of a human GSC-enriched population in serum-free medium (SFM) in the presence of epidermal growth factor and fibroblast growth factor, to that of glioma cells in serum-containing medium (SCM). SFM is the neural stem/progenitor cell (NPC) medium in which NPCs proliferate in neurospheres and this medium also has been used to enrich GSCs. We found that IL-1 beta and IL-6 were upregulated in GSC-enriched population along with increased expression of Nestin, a marker of neural stem cells. More interestingly, Smad interacting protein 1 (SIP1), which is thought to be involved in glioma cell migration and invasion, was also increased in the GSC-enriched population. The paralleled upregulation of IL-1 beta and IL-6 with Nestin and SIP1 in GSC-enriched population suggest that there is a possible correlation between them. The correlation is now under investigation. Since IL-1 beta is elevated in GSC enriched population, we further determined whether IL-1 beta plays a critical role in glioma growth. Glioma cells were co-cultured with mouse NPCs expressing IL-1 receptor antagonist (IL-1ra), which can bind to IL-1 receptors without transmitting activation signals and represents a competitive inhibitor of IL-1. Proliferation of glioma cells, which were modified to express Renilla luciferase, was measured using bioluminescence imaging. Our results showed that proliferation of glioma cells was inhibited in the co-culture with NPCs expressing IL-1ra, but not in the co-culture with NPCs without expression of IL-1ra, compared to glioma cells cultured alone. The results suggest that IL-1 has an important role in glioma cell growth and NPCs engineered to express IL-1ra have therapeutic potential for gliomas.

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 3336.

Abstract 3328: Cytotherapy with naïve rat umbilical cord matrix stem cells significantly attenuates growth of murine pancreatic cancer cells and increases mouse survival in syngeneic mice

Pancreatic cancer is one of the most aggressive human malignancies, with a very poor prognosis. It is the fourth leading cause of cancer-related morbidity and mortality in the United States. MSC derived from the human umbilical cord matrix (UCMSC) have a great potential for therapeutic use in cancer. UCMSC-based targeted gene/therapeutic-delivery and successful tumor attenuation has been demonstrated. However, the targeted stem cell therapy would be significantly safer and more applicable to human patients if unmodified postnatal stem cells alone were shown to cause tumor cell death and regress tumors, without any foreign gene transfection. Accordingly, the aim of this study was to determine the anti-cancer effect of un-engineered naïve rat UCMSC on the growth of murine pancreatic ductal carcinoma in vitro and in vivo. A mouse peritoneal model was used to test the ability of un-engineered rat UCMSC to control growth of pancreatic cancer. In addition, MTT, direct cell count, [3H] thymidine uptake, and soft agar colony assays were carried out as in vitro studies. Co-culture of rat UCMSC with PAN02 murine pancreatic carcinoma cells (UCMSC:PAN02, 1:6 and 1:3) caused G0/G1 arrest and significantly attenuated the proliferation of PAN02 carcinoma cells as monitored by MTT assay, direct cell counts, and [3H] thymidine uptake assay. Rat UCMSCs also significantly reduced PAN02 colony size and number as measured by soft agar colony assay. The in vivo mouse studies showed that rat UCMSC treatment significantly decreased the peritoneal PAN02 tumor burden 3 weeks after tumor transplantation and increased mouse survival time. Histological study revealed that intraperitoneally administered rat UCMSC survived for at least 3 weeks and the majority were found near or inside the tumor. These results indicate that naïve rat UCMSC alone remarkably attenuate the growth of pancreatic carcinoma cells in vitro and in a mouse peritoneal model. Thus, these studies imply that UCMSC could be a potential tool for targeted cytotherapy for pancreatic cancer. This work was supported by Kansas State University (KSU) Terry C. Johnson Center for Basic Cancer Research, KSU College of Veterinary Medicine Dean's fund, Kansas State Legislative Appropriation, NIH P20RR017686, P20RR015563 and R21 CA135599.

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 3328.

Abstract 5154: Human umbilical cord matrix stem cells transfected with the interferon-β gene markedly attenuated the growth of bronchioloalveolar carcinoma xenografts in mice

Mesenchymal stem cells derived from the human umbilical cord matrix (UCMSC) have great potential for therapeutic use in multiple diseases including cancer. UCMSC can be used as carriers for targeted delivery of genes or therapeutics and for local production of biologic agents. The therapeutic strategy using UCMSC as cellular vehicles for targeted gene delivery can avoid the problem of short life or excessive toxicity of a particular gene product in vivo. Interferon-β (IFN-β) has demonstrated a potent anti-tumor effect on many tumor cell lines in vitro. However, in vivo inhibition of tumor cell growth by IFN-β required blood concentrations much higher than the maximally tolerated dose. Therefore, clinical therapy by systemic administration of IFN-β was not possible. The aim of this study was to determine the anti-cancer effect of IFN-β gene transfected-UCMSC (IFN-UCMSC) on bronchioloalveolar carcinoma (BAC) cell lines in vitro and in vivo. The conditioned medium derived from IFN-UCMSC significantly attenuated cell growth of H358 and SW1573 BAC cell lines in vitro compared to the medium derived from non-transfected UCMSC. The percentage of dead cells, as measured by the trypan blue exclusion test, was significantly higher in the cells treated with the medium derived from IFN-UCMSC than UCMSC alone. The co-culture of IFN-UCMSC with cancer cells inhibited cell growth significantly through stimulation of apoptosis. Finally, systemic administration of IFN-UCMSC (0.3 million cells/injection, 5 day interval for four times) markedly attenuated tumor multiplicity and size of orthotopic H358 BAC xenografts in SCID mouse lungs. Histochemical analysis of the tumors indicated tumor-targeted localization of UCMSC and significant reduction of tumor cell proliferation index as measured by Ki-67 staining. These results clearly indicated that IFN-β production by IFN-UCMSC attenuated growth of BAC cells by inducing programmed cell death both in vitro and in vivo. This research clearly demonstrated that IFN-UCMSC are a powerful anti-cancer therapeutic tool as delivery vehicles for IFN-β. This work was supported by the KSU Terry C. Johnson Center for Basic Cancer Research, KSU Provost's Fund, KSU CVM Dean's Fund, NIH P20 RR017686 and a Joan's Legacy Research Grant.

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 5154.

A/C magnetic hyperthermia of melanoma mediated by iron(0)/iron oxide core/shell magnetic nanoparticles: a mouse study

BACKGROUND

There is renewed interest in magnetic hyperthermia as a treatment modality for cancer, especially when it is combined with other more traditional therapeutic approaches, such as the co-delivery of anticancer drugs or photodynamic therapy.

METHODS

The influence of bimagnetic nanoparticles (MNPs) combined with short external alternating magnetic field (AMF) exposure on the growth of subcutaneous mouse melanomas (B16-F10) was evaluated. Bimagnetic Fe/Fe3O4 core/shell nanoparticles were designed for cancer targeting after intratumoral or intravenous administration. Their inorganic center was protected against rapid biocorrosion by organic dopamine-oligoethylene glycol ligands. TCPP (4-tetracarboxyphenyl porphyrin) units were attached to the dopamine-oligoethylene glycol ligands.

RESULTS

The magnetic hyperthermia results obtained after intratumoral injection indicated that micromolar concentrations of iron given within the modified core-shell Fe/Fe3O4 nanoparticles caused a significant anti-tumor effect on murine B16-F10 melanoma with three short 10-minute AMF exposures. We also observed a decrease in tumor size after intravenous administration of the MNPs followed by three consecutive days of AMF exposure 24 hrs after the MNPs injection.

CONCLUSIONS

These results indicate that intratumoral administration of surface modified MNPs can attenuate mouse melanoma after AMF exposure. Moreover, we have found that after intravenous administration of micromolar concentrations, these MNPs are capable of causing an anti-tumor effect in a mouse melanoma model after only a short AMF exposure time. This is a clear improvement to state of the art.