Ratiometric spectral imaging for fast tumor detection and chemotherapy monitoring in vivo

We report a novel in vivo spectral imaging approach to cancer detection and chemotherapy assessment. We describe and characterize a ratiometric spectral imaging and analysis method and evaluate its performance for tumor detection and delineation by quantitatively monitoring the specific accumulation of targeted gallium corrole (HerGa) into HER2-positive (HER2 +) breast tumors. HerGa temporal accumulation in nude mice bearing HER2 + breast tumors was monitored comparatively by a. this new ratiometric imaging and analysis method; b. established (reflectance and fluorescence) spectral imaging; c. more commonly used fluorescence intensity imaging. We also tested the feasibility of HerGa imaging in vivo using the ratiometric spectral imaging method for tumor detection and delineation. Our results show that the new method not only provides better quantitative information than typical spectral imaging, but also better specificity than standard fluorescence intensity imaging, thus allowing enhanced in vivo outlining of tumors and dynamic, quantitative monitoring of targeted chemotherapy agent accumulation into them

Animals bearing malignant grafts reject normal grafts that express through gene transfer the same antigen.

Breaking the state of immunological unresponsiveness of tumor-bearing individuals to cancer is a prerequisite for active or passive tumor-specific immunotherapy. To study this problem the immunogenic MHC class I antigen, K216 was transfected into a progressor tumor. The transfected tumors were regularly rejected by normal mice but grew progressively in mice bearing nontransfected tumors. In addition, transgenic mice were derived to obtain normal cells and tissues expressing the same K216 gene product. Normal mice rejected K216-positive normal or malignant tissue grafts and generated K216-specific CTL in vitro and in vivo in response to these challenges. In contrast, mice bearing nontransfected tumors, though rejecting K216-positive nonmalignant tissue grafts, did not reject K216-positive tumors nor generate K216-specific CTL in response to K216-positive tumor cells. Mice bearing K216-positive tumors also rejected the nonmalignant K216-positive tissue grafts, but this in vivo response failed to lead to rejection of the simultaneously present tumor graft expressing the same antigen; in fact, immunity had no measurable effect whatsoever on tumor size or incidence and caused no selection for antigen loss variants. Taken together, the present findings suggest that transfer of expression of a target antigen into nonmalignant cells provides a way for obtaining effective stimulation of antigen-specific CTL in tumor-bearing mice, but that additional manipulations will be required to cause immunological rejection of established tumors

BMN673 sensitizes rhabdomyosarcoma tumors to irradiation in vivo

Bone and soft tissue sarcomas are mesenchymal tumors that occur rarely in adults, representing only 1% of total malignancies, but comprise up to 13% of malignant tumors in children.1 Rhabdomyosarcoma, a soft tissue sarcoma that commonly affects children, and osteosarcoma, a common bone sarcoma, exhibit aggressive tendency to metastasize and are associated with poor prognosis, high recurrence, and treatment failure.1 Sarcoma, as well as other forms of cancer, can be treated with chemotherapeutic drugs that inhibit the actions of the poly (ADP-ribose) polymerase enzyme family, which catalyze the transfer of ADP-ribose to proteins and contribute to the repair of single-stranded DNA breaks.2 Because some sarcoma cell lines display reduced DNA repair activity, these tumors might be relying on the PARP pathway for regular repair and maintenance of DNA during division.3 Because of this, PARP inhibition is targeted by molecules such as BMN673 (talazoparib), which has shown success as a treatment for BRCA1/2 and PTEN-deficient cell lines.2,4 BMN673, a recently developed PARP inhibitor with excellent in vitro activity, has been shown to increase tumor radiation sensitivity to a far greater extent than other PARP inhibitors; this action has been demonstrated to reduce tumor progression in vitro and shows promise as a treatment strategy in the clinic.2 Our study shows that the combination of BMN673 with radiation therapy reduces final rhabdomyosarcoma tumor size and slows tumor progression in mice.The Comprehensive Cancer CenterNo embargoAcademic Major: Neuroscienc

First measurements of radon-220 diffusion in mice tumors, towards treatment planning in diffusing alpha-emitters radiation therapy

Alpha-DaRT is a new method for treating solid tumors with alpha particles, relying on the release of the alpha-emitting daughter atoms of radium-224 from sources inserted into the tumor. The most important model parameters for Alpha-DaRT dosimetry are the diffusion lengths of radon-220 and lead-212, and their estimation is essential for treatment planning. The aim of this work is to provide first experimental estimates for the diffusion length of radon-220. The diffusion length of radon-220 was estimated from autoradiography measurements of histological sections taken from 24 mice-borne subcutaneous tumors of five different types. Experiments were done in two sets: fourteen in-vivo tumors, where during the treatment the tumors were still carried by the mice with active blood supply, and ten ex-vivo tumors, where the tumors were excised before source insertion and kept in a medium at 37 degrees C with the source inside. The measured diffusion lengths of radon-220 lie in the range 0.25-0.6 mm, with no significant difference between the average values measured in in-vivo and ex-vivo tumors: 0.40 $\pm$ 0.08 mm for in-vivo vs. 0.39 $\pm$ 0.07 mm for ex-vivo. However, in-vivo tumors display an enhanced spread of activity 2-3 mm away from the source. This effect is not explained by the current model and is much less pronounced in ex-vivo tumors. The average measured radon-220 diffusion lengths in both in-vivo and ex-vivo tumors lie close to the upper limit of the previously estimated range of 0.2-0.4 mm. The observation that close to the source there is no apparent difference between in-vivo and ex-vivo tumors, and the good agreement with the theoretical model in this region suggest that the spread of radon-220 is predominantly diffusive in this region. The departure from the model prediction in in-vivo tumors at large radial distances may hint at potential vascular contribution

Antitumor activity of the tea polyphenol epigallocatechin-3-gallate encapsulated in targeted vesicles after intravenous administration

The therapeutic potential of epigallocatechin gallate, a green tea polyphenol with anti-cancer properties, is limited by its inability to specifically reach tumors following intravenous administration. The purpose of this study is to determine whether a tumor-targeted vesicular formulation of epigallocatechin gallate would suppress the growth of A431 epidermoid carcinoma and B16-F10 melanoma in vitro and in vivo. Transferrin-bearing vesicles encapsulating epigallocatechin gallate were intravenously administered to mice bearing subcutaneous A431 and B16-F10 tumors. The intravenous administration of epigallocatechin gallate encapsulated in transferrin-bearing vesicles resulted in tumor suppression for 40% of A431 and B16-F10 tumors. Animal survival was improved by more than 20 days compared to controls. Encapsulation of epigallocatechin gallate in transferrin-bearing vesicles is a promising therapeutic strategy

Micro-Environment Causes Reversible Changes in DNA Methylation and mRNA Expression Profiles in Patient-Derived Glioma Stem Cells

In vitro and in vivo models are widely used in cancer research. Characterizing the similarities and differences between a patient\u27s tumor and corresponding in vitro and in vivo models is important for understanding the potential clinical relevance of experimental data generated with these models. Towards this aim, we analyzed the genomic aberrations, DNA methylation and transcriptome profiles of five parental tumors and their matched in vitro isolated glioma stem cell (GSC) lines and xenografts generated from these same GSCs using high-resolution platforms. We observed that the methylation and transcriptome profiles of in vitro GSCs were significantly different from their corresponding xenografts, which were actually more similar to their original parental tumors. This points to the potentially critical role of the brain microenvironment in influencing methylation and transcriptional patterns of GSCs. Consistent with this possibility, ex vivo cultured GSCs isolated from xenografts showed a tendency to return to their initial in vitro states even after a short time in culture, supporting a rapid dynamic adaptation to the in vitro microenvironment. These results show that methylation and transcriptome profiles are highly dependent on the microenvironment and growth in orthotopic sites partially reverse the changes caused by in vitro culturing

Multimodal wide-field two-photon excitation imaging: characterization of the technique for in vivo applications

We report fast, non-scanning, wide-field two-photon fluorescence excitation with spectral and lifetime detection for in vivo biomedical applications. We determined the optical characteristics of the technique, developed a Gaussian flat-field correction method to reduce artifacts resulting from non-uniform excitation such that contrast is enhanced, and showed that it can be used for ex vivo and in vivo cellular-level imaging. Two applications were demonstrated: (i) ex vivo measurements of beta-amyloid plaques in retinas of transgenic mice, and (ii) in vivo imaging of sulfonated gallium(III) corroles injected into tumors. We demonstrate that wide-field two photon fluorescence excitation with flat-field correction provides more penetration depth as well as better contrast and axial resolution than the corresponding one-photon wide field excitation for the same dye. Importantly, when this technique is used together with spectral and fluorescence lifetime detection modules, it offers improved discrimination between fluorescence from molecules of interest and autofluorescence, with higher sensitivity and specificity for in vivo applications

Malignant phyllodes tumors display mesenchymal stem cell features and aldehyde dehydrogenase/disialoganglioside identify their tumor stem cells.

IntroductionAlthough breast phyllodes tumors are rare, there is no effective therapy other than surgery. Little is known about their tumor biology. A malignant phyllodes tumor contains heterologous stromal elements, and can transform into rhabdomyosarcoma, liposarcoma and osteosarcoma. These versatile properties prompted us to explore their possible relationship to mesenchymal stem cells (MSCs) and to search for the presence of cancer stem cells (CSCs) in phyllodes tumors.MethodsParaffin sections of malignant phyllodes tumors were examined for various markers by immunohistochemical staining. Xenografts of human primary phyllodes tumors were established by injecting freshly isolated tumor cells into the mammary fat pad of non-obese diabetic-severe combined immunodeficient (NOD-SCID) mice. To search for CSCs, xenografted tumor cells were sorted into various subpopulations by flow cytometry and examined for their in vitro mammosphere forming capacity, in vivo tumorigenicity in NOD-SCID mice and their ability to undergo differentiation.ResultsImmunohistochemical analysis revealed the expression of the following 10 markers: CD44, CD29, CD106, CD166, CD105, CD90, disialoganglioside (GD2), CD117, Aldehyde dehydrogenase 1 (ALDH), and Oct-4, and 7 clinically relevant markers (CD10, CD34, p53, p63, Ki-67, Bcl-2, vimentin, and Globo H) in all 51 malignant phyllodes tumors examined, albeit to different extents. Four xenografts were successfully established from human primary phyllodes tumors. In vitro, ALDH+ cells sorted from xenografts displayed approximately 10-fold greater mammosphere-forming capacity than ALDH- cells. GD2+ cells showed a 3.9-fold greater capacity than GD2- cells. ALDH+/GD2+cells displayed 12.8-fold greater mammosphere forming ability than ALDH-/GD2- cells. In vivo, the tumor-initiating frequency of ALDH+/GD2+ cells were up to 33-fold higher than that of ALDH+ cells, with as few as 50 ALDH+/GD2+ cells being sufficient for engraftment. Moreover, we provided the first evidence for the induction of ALDH+/GD2+ cells to differentiate into neural cells of various lineages, along with the observation of neural differentiation in clinical specimens and xenografts of malignant phyllodes tumors. ALDH+ or ALDH+/GD2+ cells could also be induced to differentiate into adipocytes, osteocytes or chondrocytes.ConclusionsOur findings revealed that malignant phyllodes tumors possessed many characteristics of MSC, and their CSCs were enriched in ALDH+ and ALDH+/GD2+ subpopulations