Pancreatic ductal adenocarcinoma (PDAC) has the lowest 5-year survival of any major cancer. Its highly aggressive and treatment-resistant phenotype often leads to early metastasis and poor outcomes. For patients with unresectable, locally advanced tumors (up to 50% of cases), local control remains a significant issue. Stereotactic body radiation therapy (SBRT) is an emerging treatment option for locally advanced PDAC. SBRT can provide significant advantages for patients’ quality of life over conventional chemoradiation, however, the rate of distant metastasis remains high.

Many studies show that the tumor microenvironment (i.e., stromal cells, blood vessels, and extracellular matrix) exerts a profound effect on the development of metastases and treatment resistance. In PDAC, this effect is especially true as it is characterized by a stroma-rich, hypoxic tumor microenvironment. The goal of this study is to investigate the effects of SBRT on the elements of the PDAC tumor microenvironment responsible for clinically relevant complications. We will use a novel mouse-imaging platform for longitudinal, intravital fluorescence microscopy to characterize the effect of SBRT on tumor vasculature and hypoxia, as well as pancreatic stellate cells and fibrillar collagen in the tumor. Observing how these stromal elements respond to SBRT will improve our understanding of how PDAC tumors develop treatment-resistance and subsequently invade the surrounding tissues.

This image was captured in a live mouse using a laser-scanning confocal microscope (LSM710, Zeiss). The pancreatic tumor (blue), blood vessels (green), and pancreatic stellate cells (pink) are visualized.

Nanosurfaces have improved clinical success rate of implants by increasing bone to implant contact. Currently there is lack of detailed understanding on the healing mechanism at the cellular level. Neovascularization is considered an essential prerequisite to osteogenesis, but no previous reports have examined the effect of implant surface topography on the spatiotemporal pattern of neovascularization during peri-implant healing.

We have developed a cranial window model to study peri-implant healing intravitally over clinically relevant time scales as a function of implant surface design. Quantitative intravital confocal imaging revealed that changing the surface topography of implants significantly affects peri-implant neovascularization. We are currently investigating the influence of vascular changes on other cascades involved in wound healing, including progenitor cell migration and immune response. Once we understand the healing mechanism under healthy conditions, we can improve the clinical efficacy of next-generation implants in cure-limiting diseased conditions.

Blood vessels forming on a nano-surfaced implant. The radial arrangement of fluorescently labeled neovascularization (green), established during early endosseous healing associated with a nano-topographically complex cruciate titanium implant (blue), as visualized by intravital microscopy using a new cranial Implant window chamber model.

Acute myeloid leukemia (AML) is a disease of the bone marrow (BM) microenvironment, involving the growth of malignant cells close to other cells of the BM. Current animal studies focus on administering treatment and evaluating the effect at a later time, with minimal knowledge about what occurs between these two time points. Using two innovative and complementary experimental methods developed by Drs. DaCosta and Minden’s teams, our project is able to transform the way we investigate the development of AML in vivo in animal models of the disease.

The ability to observe in real-time the behavior of different cell types within the “living” BM can provide novel insights into the effect of the treatment and enable the development of new (immuno)therapies against this disease. Results obtained in this study have the potential to guide clinical trials at Princess Margaret involving the use of autologous IL-12 expressing AML cells and allogeneic double negative T cells (DNT) in patients at high risk of relapse. The experimental tools developed in this unique bench-to-bedside collaboration will also open up new avenues for basic research in leukemia, which could help overcome previous technological barriers in the field.

Biofilms are complex, organised communities of bacteria. Individual cells sense and communicate with other nearby cells to form a network in which they can share resources and defend from chemical and physical interference. Although some of these biofilms do exist symbiotically, the results of biofilm infection can cause devastating effects on the human body and subsequently on the health care industry. Clinical signs and symptoms are the primary tools to identify biofilms in wounds, however these tools are unspecific and require prolonged infection in patients.

We propose to use the fluorescence imaging device MolecuLight i:X, to monitor wound status, and investigate the differences in biofilm and infection autofluorescence in diabetic foot ulcers. This study will require the use of punch biopsies and histological staining to identify a biofilm based on phenotypic properties and to inform images of wounds containing suspected biofilm. Our future aim is to develop methods to locate biofilm and planktonic infection at the point of care using fluorescence imaging and digital solutions.

Image of suspected S. aureus biofilm grown on an ex vivo wound model and captured with a scanning electron microscope. The sticky extracellular matrix occludes the S. aureus cocci at the biofilm surface and can be seen between cells, like glue, holding them together.