Background

In this study, we investigated the advantages of fluorescence-guided surgery (FGS) in mice of a portable hand-sized imaging system compared with a large fluorescence imaging system or a long-working-distance fluorescence microscope.

Methods

Mouse models of human pancreatic cancer for FGS included the following: (1) MiaPaCa-2-expressing green fluorescent protein, (2) BxPC3 labeled with Alexa Fluor 488-conjucated anti-carcinoembryonic antigen (CEA) antibody, and (3) patient-derived orthotopic xenograft (PDOX) labeled with Alexa Fluor 488-conjugated anti-carbohydrate antigen 19-9 antibody.

Results

Each device could clearly detect the primary MiaPaCa-2-green fluorescent protein tumor and any residual tumor after FGS. In the BxPC3 model labeled with Alexa Fluor 488-conjugated anti-CEA, each device could detect the primary tumor, but the MVX10 could not clearly detect the residual tumor remaining after FGS whereas the other devices could. In the PDOX model labeled with Alexa Fluor 488-conjugated anti-carbohydrate antigen 19-9, only the portable hand-held device could distinguish the residual tumor from the background, and complete resection of the residual tumor was achieved under fluorescence navigation.

Conclusions

The results described in the present report suggest that the hand-held mobile imaging system can be applied to the clinic for FGS because of its convenient size and high sensitivity which should help make FGS widely used.

The aim of the present study was to examine the efficacy of tumor-targeting Salmonella typhimurium A1-R treatment following anti-vascular endothelial growth factor (VEGF) therapy on VEGF-positive human pancreatic cancer. A pancreatic cancer patient-derived orthotopic xenograft (PDOX) that was VEGF-positive and an orthotopic VEGF-positive human pancreatic cancer cell line (MiaPaCa-2-GFP) as well as a VEGF-negative cell line (Panc-1) were tested. Nude mice with these tumors were treated with gemcitabine (GEM), bevacizumab (BEV), and S. typhimurium A1-R. BEV/GEM followed by S. typhimurium A1-R significantly reduced tumor weight compared to BEV/GEM treatment alone in the PDOX and MiaPaCa-2 models. Neither treatment was as effective in the VEGF-negative model as in the VEGF-positive models. These results demonstrate that S. typhimurium A1-R following anti-angiogenic therapy is effective on pancreatic cancer including the PDOX model, suggesting its clinical potential.

Background

Fluorescence-guided surgery (FGS) can enable successful cancer surgery where bright-light surgery often cannot. There are three important issues for FGS going forward toward the clinic: (a) proper tumor labeling, (b) a simple portable imaging system for the operating room, and (c) patient-like mouse models in which to develop the technology. The present report addresses all three.

Materials and methods

Patient colon tumors were initially established subcutaneously in nonobese diabetic (NOD)/severe combined immune deficiency (SCID) mice immediately after surgery. The tumors were then harvested from NOD/SCID mice and passed orthotopically in nude mice to make patient-derived orthotopic xenograft (PDOX) models. Eight weeks after orthotopic implantation, a monoclonal anti-carcinoembryonic antigen (CEA) antibody conjugated with AlexaFluor 488 (Molecular Probes Inc., Eugene, OR) was delivered to the PDOX models as a single intravenous dose 24 hours before laparotomy. A hand-held portable fluorescence imaging device was used.

Results

The primary tumor was clearly visible at laparotomy with the portable fluorescence imaging system. Frozen section microscopy of the resected specimen demonstrated that the anti-CEA antibody selectively labeled cancer cells in the colon cancer PDOX. The tumor was completely resected under fluorescence navigation. Histologic evaluation of the resected specimen demonstrated that cancer cells were not present in the margins, indicating successful tumor resection. The FGS animals remained tumor free for over 6 months.

Conclusions

The results of the present report indicate that FGS using a fluorophore-conjugated anti-CEA antibody and portable imaging system improves efficacy of resection for CEA-positive colorectal cancer. These data provide the basis for clinical trials.

The aim of this study is to determine if ultraviolet light (UVC) irradiation in combination with fluorescence-guided surgery (FGS) can eradicate metastatic human pancreatic cancer in orthotopic nude-mouse models. Two weeks after orthotopic implantation of human MiaPaCa-2 pancreatic cancer cells, expressing green fluorescent protein (GFP), in nude mice, bright-light surgery (BLS) was performed on all tumor-bearing mice (n = 24). After BLS, mice were randomized into 3 treatment groups; BLS-only (n = 8) or FGS (n = 8) or FGS-UVC (n = 8). The residual tumors were resected using a hand-held portable imaging system under fluorescence navigation in mice treated with FGS and FGS-UVC. The surgical resection bed was irradiated with 2700 J/m2 UVC (254 nm) in the mice treated with FGS-UVC. The average residual tumor area after FGS (n = 16) was significantly smaller than after BLS only (n = 24) (0.135±0.137 mm2 and 3.338±2.929 mm2, respectively; p = 0.007). The BLS treated mice had significantly reduced survival compared to FGS- and FGS-UVC-treated mice for both relapse-free survival (RFS) (p<0.001 and p<0.001, respectively) and overall survival (OS) (p<0.001 and p<0.001, respectively). FGS-UVC-treated mice had increased RFS and OS compared to FGS-only treated mice (p = 0.008 and p = 0.025, respectively); with RFS lasting at least 150 days indicating the animals were cured. The results of the present study suggest that UVC irradiation in combination with FGS has clinical potential to increase survival.