A Mouse Model of Fluorescent Protein-expressing Disseminated Peritoneal Lymphoma for Fluorescence-guided Surgery

Abstract

Our laboratory has developed fluorescence-guided surgery (FGS) in mouse models of cancer (1). FGS on orthotopic nude-mouse models of colon cancer (2-6), pancreatic cancer (7-19), lung cancer (20), sarcoma (21), glioma (22) and liver metastasis (5, 6, 23) has been shown to have significant improvement over bright-light surgery (BLS). A small handheld fluorescence imaging device has recently been used for FGS in orthotopic mouse models (4, 13) that can be used in the clinic. The mouse models used thus far for FGS have also included patient-derived orthotopic xenograft (PDOX) models (3,4,13,15,16,18,19) in nude mice.Recently, we have developed a model of the EL-4 mouse lymphoma expressing red fluorescent protein (EL4-RFP). A syngeneic color-coded imageable lymphoma model was previously established to visualize recruitment of host stromal cells by malignant lymphoma during metastasis. EL4-RFP cells were injected into the tail vein of C57/BL6-GFP transgenic mice. EL4-RFP metastasis was observed in multiple sites, which were also enriched in host GFPexpressing cells. Furthermore, EL4-RFP lymphoma cells were also observed along with host GFP stromal cells in the peripheral blood and bone marrow, as well as the liver (24).RFP-expressing EL4 lymphoma cells were also previously injected subcutaneously in C57/BL6 GFP transgenic mice and formed tumors by 35 days after cell transplantation. Using the Dino-Lite hand-held, portable fluorescence imaging system, subcutaneous tumors including the tumor microenvironment (TME) were clearly visualized and resected. In the resected tumor, GFP-expressing host stromal cells, including adipocyte-like cells, and blood vessels containing lymphocytes were observed by color-coded confocal microscopy to be closely associated with the lymphoma cells (25).The present report describes successful FGS of peritoneally-disseminated EL-4-RFP, a model of highlychallenging cancer surgery. Materials and MethodsMouse experiments. All experiments were conducted in accordance with the institutional guidelines of Gifu University, Gifu, Japan, and approved by the animal research committee and the committee on living modified organisms of Gifu University. In order to minimize any suffering of the animals, anesthesia and analgesics were used for all surgical experiments. Animals were anesthetized by intramuscular injection of a 0.02 ml solution of 100 mg/kg ketamine. The response of animals during surgery was monitored to ensure adequate depth of anesthesia. The use of 4483

Biogenic Imaging Contrast Agents

“…As an FL imaging contrast agent, FP facilitates labeling of organelle inside cells (Figure 3C ), marking embryonic cells to visualize embryo development (Figure 3D ), [ 28 , 29 ] monitoring tumor metastasis (Figure 3E ), and enabling FL‐guided surgery. [ 30 , 31 ] In addition, FPs with wide spectrum of color enable the observation of multiple subcellular structures simultaneously through multicolor labeling (Figure 3F ). Currently, the main issue of in vivo FL imaging lies in the limited tissue penetration; hence, vast demand exists to improve the imaging performance within the context of intact organisms by developing longer wavelength emissive NIR FPs.…”

Nanobiotechnology medical applications: Overcoming challenges through innovation

“…The combination of diagnostic techniques and bioinformatics allows the most unique, specific biomarkers for each type of cancer to be identified for use as the target molecule, which ensures that only cancerous cells will be targeted. This technique has been successful in mouse models and is on its way to becoming a common technique for the enhancement of precision surgery (69)(70)(71).…”