Photoimmunotherapy Inhibits Tumor Recurrence After Surgical Resection on a Pancreatic Cancer Patient-Derived Orthotopic Xenograft (PDOX) Nude Mouse Model.

BACKGROUND: Photoimmunotherapy (PIT) uses a target-specific photosensitizer based on a near-infrared (NIR) phthalocyanine dye, IR700, to induce tumor necrosis after irradiation with NIR light to kill cancer cells, such as those that remain after surgery. The purpose of the present study was to sterilize the surgical bed after pancreatic cancer resection with PIT in carcinoembryonic antigen (CEA)-expressing, patient-derived, orthotopic xenograft (PDOX) nude mouse models. METHODS: After confirmation of tumor engraftment, mice were randomized to two groups: bright light surgery (BLS)-only and BLS + PIT. Each treatment arm consisted of seven tumor-bearing mice. BLS was performed under standard bright-field with an MVX10 long-working distance, high-magnification microscope on all mice. For BLS + PIT, anti-CEA antibody conjugated with IR700 (anti-CEA-IR700) (50 µg) was injected intravenously in all mice 24 h before surgery. After the surgery, the resection bed was then irradiated with a red-light-emitting diode at 690 ± 5 nm with a power density of 150 mW/cm(2). RESULTS: Anti-CEA-IR700 labelled and illuminated the pancreatic cancer PDOX. Minimal residual cancer of the PDOX was detected by fluorescence after BLS. The local recurrence rate was 85.7 % for BLS-only and 28.6 % for BLS + PIT-treated mice (p = 0.05). The average recurrent tumor weight was 1149.0 ± 794.6 mg for BLS-only and 210.8 ± 336.9 mg for BLS + PIT-treated mice (p = 0.015). CONCLUSION: Anti-CEA-IR700 was able to label and illuminate a pancreatic cancer PDOX nude mouse model sufficiently for PIT. PIT reduced recurrence by eliminating remaining residual cancer cells after BLS.

Fluorescence-guided surgery, but not bright-light surgery, prevents local recurrence in a pancreatic cancer patient derived orthotopic xenograft (PDOX) model resistant to neoadjuvant chemotherapy (NAC).

BACKGROUND: The aim of this study is to determine the efficacy of neoadjuvant chemotherapy (NAC) with gemcitabine (GEM) in combination with fluorescence-guided surgery (FGS) on a pancreatic cancer patient derived orthotopic xenograft (PDOX) model. METHODS: A PDOX model was established from a CEA-positive tumor from a patient who had undergone a pancreaticoduodenectomy for pancreatic adenocarcinoma. Mice were randomized to 4 groups: bright light surgery (BLS) only; BLS + NAC; FGS only; and FGS + NAC. An anti-CEA antibody conjugated to DyLight 650 was administered intravenously via the tail vein of mice with a pancreatic cancer PDOX 24 h before surgery. RESULTS: The PDOX was clearly labeled with fluorophore-conjugated anti-CEA antibody. Only one out of 8 mice had local recurrence in the FGS only group and zero out of 8 mice had local recurrence in the FGS + NAC which was significantly lower than BLS only or BLS + NAC mice, where local disease recurred in 6 out of 8 mice in each treatment group (p = 0.041 and p = 0.007, respectively). NAC did not significantly reduce recurrence rates when combined with either FGS or BLS. CONCLUSION: These results indicate that FGS can significantly reduce local recurrence compared to BLS in pancreatic cancer resistant to NAC.

Photoimmunotherapy lowers recurrence after pancreatic cancer surgery in orthotopic nude mouse models.

BACKGROUND: Photoimmunotherapy (PIT) is based on the use of a monoclonal antibody specific to cancer epitopes conjugated to a photosensitizer near-infrared phthalocyanine dye (IR700). In this study, PIT with IR700 conjugated to anti-carcinoembryonic antigen (CEA) was used as an adjunct to surgery in orthotopically-implanted human pancreatic cancer in a nude mouse model to eliminate microscopic disease in the post-surgical tumor bed and prevent local as well as metastatic recurrence. MATERIALS AND METHODS: Athymic nude mice were orthotopically implanted with the human pancreatic cancer cell line BxPC3 expressing green fluorescent protein. After tumor engraftment, the mice were divided into two groups as follows: bright light surgery (BLS) + anti-CEA-IR700 + 690 nm laser (PIT); and BLS only. Anti-CEA-IR700 (100 µg) was administered to the treatment group via tail-vein injection 24 h before therapy. Tumors were resected, and the surgical bed was treated with intraoperative phototherapy at an intensity of 150 mW/cm(2) for 30 min. Mice were imaged noninvasively for 8 wk using an OV-100 small animal fluorescence imager. RESULTS: BLS + PIT reduced local recurrence to 1/7 mice from 7/7 mice with BLS-only (P = 0.001) and metastatic recurrence to 2/7 mice compared with 6/7 mice with BLS-only (P = 0.03). Local tumor growth continued at a rapid rate after BLS-only compared with BLS + PIT where almost no local growth occurred. There was a significant difference in tumor size between mice in the BLS + PIT (2.14 mm(2), 95% confidence interval [CI] [-2.06 to 6.34] and BLS-only groups (115.2 mm(2), 95% CI [88.8-141.6]) at 6 wk after surgery (P < 0.001). There was also a significant difference in tumor weight between the BLS + PIT group (6.65 mg, 95% CI [-6.35 to 19.65] and BLS-only group (1100 mg, 95% CI [794-1406] at 8 wk after surgery (P < 0.001). CONCLUSIONS: PIT holds promise in the treatment of pancreatic cancer and may serve as a useful adjunct to surgery in the eradication of microscopic residual disease that can lead to both local and metastatic recurrence. Further studies are warranted to investigate the potential toxicities of PIT, especially with regard to anastomoses, such as those involved in pancreaticoduodenectomy.

Selective efficacy of zoledronic acid on metastasis in a patient-derived orthotopic xenograph (PDOX) nude-mouse model of human pancreatic cancer.

BACKGROUND AND OBJECTIVES: Patient-derived orthotopic xenograft (PDOX) nude-mouse models replicate the behavior of clinical cancer, including metastasis. The objective of the study was to determine the efficacy of zoledronic acid (ZA) on metastasis of a patient-derived orthotopic xenograft (PDOX) nude-mouse model of pancreatic cancer. METHODS: In the present study, we examined the efficacy of ZA on pancreatic cancer growth and metastasis in a PDOX nude-mouse model. RESULTS: ZA monotherapy did not significantly suppress primary tumor growth. However, the primary tumor weight of gemcitabine (GEM) and combination GEM + ZA-treated mice was significantly decreased compared to the control group (GEM: P = 0.003; GEM + ZA: P = 0.002). The primary tumor weight of GEM + ZA-treated mice was significantly decreased compared to GEM-treated mice (P = 0.016). The metastasis weight decreased in ZA- or GEM-treated mice compared to the control group (ZA: P = 0.009; GEM: P = 0.007. No metastasis was detected in combination GEM + ZA-treated mice compared to the control group (GEM + ZA; P = 0.005). CONCLUSIONS: The results of the present study indicate that ZA can selectively target metastasis in a pancreatic cancer PDOX model and that the combination of ZA and GEM should be evaluated clinically in the near future for this highly treatment-resistant disease.

Efficacy of Salmonella typhimurium A1-R versus chemotherapy on a pancreatic cancer patient-derived orthotopic xenograft (PDOX).

The aim of this study is to determine the efficacy of tumor-targeting Salmonella typhimurium A1-R (A1-R) on pancreatic cancer patient-derived orthotopic xenografts (PDOX). The PDOX model was originally established from a pancreatic cancer patient in SCID-NOD mice. The pancreatic cancer PDOX was subsequently transplanted by surgical orthotopic implantation (SOI) in transgenic nude red fluorescent protein (RFP) mice in order that the PDOX stably acquired red fluorescent protein (RFP)-expressing stroma for the purpose of imaging the tumor after passage to non-transgenic nude mice in order to visualize tumor growth and drug efficacy. The nude mice with human pancreatic PDOX were treated with A1-R or standard chemotherapy, including gemcitabine (GEM), which is first-line therapy for pancreatic cancer, for comparison of efficacy. A1-R treatment significantly reduced tumor weight, as well as tumor fluorescence area, compared to untreated control (P = 0.011), with comparable efficacy of GEM, CDDP, and 5-FU. Histopathological response to treatment was defined according to Evans's criteria and A1-R had increased efficacy compared to standard chemotherapy. The present report is the first to show that A1-R is effective against a very low-passage patient tumor, in this case, pancreatic cancer. The data of the present report suggest A1-1 will have clinical activity in pancreatic cancer, a highly lethal and treatment-resistant disease and may be most effectively used in combination with other agents.

Hand-held high-resolution fluorescence imaging system for fluorescence-guided surgery of patient and cell-line pancreatic tumors growing orthotopically in nude mice.

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.

TAMIS-assisted laparoscopic low anterior resection with total mesorectal excision in a cadaveric series.

BACKGROUND: To demonstrate the feasibility of an innovative technique for the surgical management of rectal cancer, we performed transanal minimally invasive surgery assisted low anterior resection with total mesorectal excision (TAMIS-assisted LAR with TME) in a cadaver model. Transanal LAR via natural orifice transluminal endoscopic surgery has been reported in cadaveric series using rigid transanal platforms. This procedure has not been described using a combination of a single incision laparoscopy and TAMIS transanal endoscopic platform. We describe the first cadaveric series of TAMIS-assisted LAR with TME. METHODS: TAMIS-assisted LAR with TME was successfully performed in five fresh human cadavers. The procedure was performed using the mini-Gelpoint single incision platform and the Gelpoint Path TAMIS platform (Applied Medical, Rancho Santa Margarita, CA). The variables recorded were age, body mass index (BMI), operative time, complications, and specimen length. The grade of the TME was determined by evaluation of the specimen by photo documentation by a gastrointestinal pathologist. RESULTS: All cadavers were male with a mean age of 71 ± 8 years and mean BMI of 28 ± 3 kg/m(2). The mean operative time was 200 ± 55 min (range 128-249 min). The quality of the TME was grade I (complete) with intact mesorectum in all five cases. The mean specimen length was 36.8 ± 3.4 cm. CONCLUSIONS: TAMIS-assisted LAR with TME was feasible. A high-quality TME can be achieved using this innovative technique. Transanal endoscopic total mesorectal dissection may revolutionize the surgical management of rectal cancer. However, multicenter clinical trials are needed to further evaluate the oncologic safety and surgical outcomes of transanal endoscopic TME using various platforms before widespread application of this new technique.

High expression of bone morphogenetic protein (BMP) 6 and BMP7 are associated with higher immune cell infiltration and better survival in estrogen receptor­positive breast cancer.

There are conflicted experimental results on the role of bone morphogenetic proteins (BMPs) in cancer. Some results suggest that BMPs act as tumor suppressors while other findings indicate that BMPs are oncogenic factors. In the present study, we aimed to investigate the association of BMP expression and the survival of breast cancer patients utilizing The Cancer Genome Atlas (TCGA). High expression levels of BMP1 (P<0.001), BMP3 (P=0.002), BMP5 (P=0.002), BMP7 (P<0.001) and BMPR1A (P<0.001) were associated with better overall survival (OS). On the other hand, high expression levels of BMP6 (P<0.001), BMP8A (P=0.031), BMP8B (P<0.001) and BMPR1B (P=0.005) were associated with worse OS. Most of the BMPs demonstrated differential expression levels between normal and tumor tissues. High expression of BMP7 was found to be significantly associated with better prognosis in both estrogen receptor (ER)­positive (ER+) (P<0.001) and ER­negative (ER­) tumors (P<0.001), whereas high expression of BMP6 was associated with better prognosis only in ER+ tumors (P=0.004); it was associated with worse prognosis in ER­ tumors (P=0.006). In the ER+ tumors, high expression of BMP7 as well as BMP6 were associated with higher infiltration of anticancer immune cells and cytolytic activity. These results suggest that high expression levels of BMP7 as well as BMP6 possess higher anticancer immunity which results in better prognosis in ER+ breast cancer. In conclusion, BMP expression profiles may be useful for prognostication. Intervention in this pathway may serve to improve outcomes, manage metastatic disease and assist in clinical decision making on optimal therapy based on the risk of recurrence or metastasis.

A novel method for RNA extraction from FFPE samples reveals significant differences in biomarker expression between orthotopic and subcutaneous pancreatic cancer patient-derived xenografts.

Next-generation sequencing (NGS) can identify and validate new biomarkers of cancer onset, progression and therapy resistance. Substantial archives of formalin-fixed, paraffin-embedded (FFPE) cancer samples from patients represent a rich resource for linking molecular signatures to clinical data. However, performing NGS on FFPE samples is limited by poor RNA purification methods. To address this hurdle, we developed an improved methodology for extracting high-quality RNA from FFPE samples. By briefly integrating a newly-designed micro-homogenizing (mH) tool with commercially available FFPE RNA extraction protocols, RNA recovery is increased by approximately 3-fold while maintaining standard A260/A280 ratios and RNA quality index (RQI) values. Furthermore, we demonstrate that the mH-purified FFPE RNAs are longer and of higher integrity. Previous studies have suggested that pancreatic ductal adenocarcinoma (PDAC) gene expression signatures vary significantly under in vitro versus in vivo and in vivo subcutaneous versus orthotopic conditions. By using our improved mH-based method, we were able to preserve established expression patterns of KRas-dependency genes within these three unique microenvironments. Finally, expression analysis of novel biomarkers in KRas mutant PDAC samples revealed that PEAK1 decreases and MST1R increases by over 100-fold in orthotopic versus subcutaneous microenvironments. Interestingly, however, only PEAK1 levels remain elevated in orthotopically grown KRas wild-type PDAC cells. These results demonstrate the critical nature of the orthotopic tumor microenvironment when evaluating the clinical relevance of new biomarkers in cells or patient-derived samples. Furthermore, this new mH-based FFPE RNA extraction method has the potential to enhance and expand future FFPE-RNA-NGS cancer biomarker studies.

Patient-derived mouse models of cancer need to be orthotopic in order to evaluate targeted anti-metastatic therapy.

Patient-derived xenograft (PDX) mouse models of cancer are emerging as an important component of personalized precision cancer therapy. However, most models currently offered to patients have their tumors subcutaneously-transplanted in immunodeficient mice, which rarely metastasize. In contrast, orthotopic-transplant patient-derived models, termed patient-derived orthotopic xenografts (PDOX), usually metastasize as in the patient. We demonstrate in the present report why orthotopic models are so important for the patient, since primary and metastatic tumors developed in an orthotopic model can have differential chemosensitivity, not detectable in standard subcutaneous tumor models. A subcutaneous nude mouse model of HER-2 expressing cervical carcinoma was not sensitive to entinostat (a benzamide histone deactylase inhibitor), which also did not inhibit primary tumor growth in a PDOX model of the same tumor. However, in the PDOX model, entinostat alone significantly reduced the metastatic tumor burden, compared to the control. Thus, only the PDOX model could be used to discover the anti-metastatic activity of entinostat for this patient. The results of the present report indicate the importance of using mouse models that can recapitulate metastatic cancer for precisely individualizing cancer therapy.

Undescended parathyroid adenoma.

Undescended parathyroid adenomas are rare, representing 0.08% of all parathyroid adenomas; however, they make up 7% of the underlying cause of failed cervical exploration in patients with persistent primary hyperparathyroidism. A 43-year-old woman with no significant medical or family history presented with fatigue and was diagnosed with primary hyperparathyroidism; however, preoperative imaging including sestamibi scan and ultrasound was unable to identify the hyperfunctioning gland. She underwent a neck exploration and hemithyroidectomy and partial parathyroidectomy with failure of resolution of her disease. Subsequent work up including a CT of the neck demonstrated a 1.9 cm mass adjacent to the left submandibular gland. This was removed with postoperative normalisation of the patient's serum calcium and parathyroid hormone levels.

MUC1 selectively targets human pancreatic cancer in orthotopic nude mouse models.

The goal of this study was to determine whether MUC1 antibody conjugated with a fluorophore could be used to visualize pancreatic cancer. Anti-MUC1 (CT2) antibody was conjugated with 550 nm or 650 nm fluorophores. Nude mouse were used to make subcutaneous and orthotopic models of pancreatic cancer. Western blot and flow cytometric analysis confirmed the expression of MUC1 in human pancreatic cancer cell lines including BxPC-3 and Panc-1. Immunocytochemistry with fluorophore conjugated anti-MUC1 antibody demonstrated fluorescent areas on the membrane of Panc-1 cancer cells. After injecting the conjugated anti-MUC1 antibodies via the tail vein, subcutaneously transplanted Panc-1 and BxPC-3 tumors emitted strong fluorescent signals. In the subcutaneous tumor models, the fluorescent signal from the conjugated anti-MUC1 antibody was noted around the margin of the tumor and space between the cells. The conjugated anti-MUC1 antibody bound the tumor in orthotopically-transplanted Panc-1 and BxPC-3 models enabling the tumors to be imaged. This study showed that fluorophore conjugated anti-MUC1 antibodies could visualize pancreatic tumors in vitro and in vivo and may help to improve the diagnosis and treatment of pancreatic cancer.

Near infra-red photoimmunotherapy with anti-CEA-IR700 results in extensive tumor lysis and a significant decrease in tumor burden in orthotopic mouse models of pancreatic cancer.

Photoimmunotherapy (PIT) of cancer utilizes tumor-specific monoclonal antibodies conjugated to a photosensitizer phthalocyanine dye IR700 which becomes cytotoxic upon irradiation with near infrared light. In this study, we aimed to evaluate the efficacy of PIT on human pancreatic cancer cells in vitro and in vivo in an orthotopic nude mouse model. The binding capacity of anti-CEA antibody to BxPC-3 human pancreatic cancer cells was determined by FACS analysis. An in vitro cytotoxicity assay was used to determine cell death following treatment with PIT. For in vivo determination of PIT efficacy, nude mice were orthotopically implanted with BxPC-3 pancreatic tumors expressing green fluorescent protein (GFP). After tumor engraftment, the mice were divided into two groups: (1) treatment with anti-CEA-IR700 + 690 nm laser and (2) treatment with 690 nm laser only. Anti-CEA-IR700 (100 µg) was administered to group (1) via tail vein injection 24 hours prior to therapy. Tumors were then surgically exposed and treated with phototherapy at an intensity of 150 mW/cm2 for 30 minutes. Whole body imaging was done subsequently for 5 weeks using an OV-100 small animal imaging system. Anti-CEA-IR700 antibody bound to the BxPC3 cells to a high degree as shown by FACS analysis. Anti-CEA-IR700 caused extensive cancer cell killing after light activation compared to control cells in cytotoxicity assays. In the orthotopic models of pancreatic cancer, the anti-CEA-IR700 group had significantly smaller tumors than the control after 5 weeks (p<0.001). There was no significant difference in the body weights of mice in the anti-CEA-IR700 and control groups indicating that PIT was well tolerated by the mice.

Tumor-Targeting Salmonella typhimurium A1-R in Combination with Trastuzumab Eradicates HER-2-Positive Cervical Cancer Cells in Patient-Derived Mouse Models.

We have previously developed mouse models of HER-2-positive cervical cancer. Tumors in nude mice had histological structures similar to the original tumor and were stained by anti-HER-2 antibody in the same pattern as the patient's cancer. We have also previously developed tumor-targeting Salmonella typhimurium A1-R and have demonstrated its efficacy against patient-derived tumor mouse models, both alone and in combination. In the current study, we determined the efficacy of S. typhimurium A1-R in combination with trastuzumab on a patient-cancer nude-mouse model of HER-2 positive cervical cancer. Mice were randomized to 5 groups and treated as follows: (1) no treatment; (2) carboplatinum (30 mg/kg, ip, weekly, 5 weeks); (3) trastuzumab (20 mg/kg, ip, weekly, 5 weeks); (4) S. typhimurium A1-R (5 × 107 CFU/body, ip, weekly, 5 weeks); (5) S. typhimurium A1-R (5 × 107 CFU/body, ip, weekly, 5 weeks) + trastuzumab (20 mg/kg, ip, weekly, 5 weeks). All regimens had significant efficacy compared to the untreated mice. The relative tumor volume of S. typhimurium A1-R + trastuzumab-treated mice was smaller compared to trastuzumab alone (p = 0.007) and S. typhimurium A1-R alone (p = 0.039). No significant body weight loss was found compared to the no treatment group except for carboplatinum-treated mice (p = 0.021). Upon histological examination, viable tumor cells were not detected, and replaced by stromal cells in the tumors treated with S. typhimurium A1-R + trastuzumab. The results of the present study suggest that S. typhimurium A1-R and trastuzumab in combination are highly effective against HER-2-expressing cervical cancer.

Tumor-Targeting Salmonella typhimurium A1-R Arrests a Chemo-Resistant Patient Soft-Tissue Sarcoma in Nude Mice.

A patient-derived nude-mouse model of soft-tissue sarcoma has been established and treated in the following groups: (1) untreated controls; (2) gemcitabine (GEM) (80 mg/kg, ip, weekly, 3 weeks); (3) Pazopanib (100 mg/kg, orally, daily, 3 weeks) and (4) Salmonella typhimurium A1-R (5 × 10(7) CFU/body, ip, weekly, 3 weeks). The sarcoma was resistant to GEM (p = 0.879). Pazopanib tended to reduce the tumor volume compared to the untreated mice, but there was no significant difference (p = 0.115). S. typhimurium A1-R significantly inhibited tumor growth compared to the untreated mice (p = 0.001). S. typhimurium A1-R was the only effective treatment for the soft-tissue sarcoma nude mouse model among all treatments including a newly approved multiple tyrosine kinase inhibitor; Pazopanib. These results suggest tumor-targeting S. typhimurium A1-R is a promising treatment for chemo-resistant soft-tissue sarcoma.

Establishment of a patient-derived orthotopic Xenograft (PDOX) model of HER-2-positive cervical cancer expressing the clinical metastatic pattern.

Squamous cell carcinoma of the cervix, highly prevalent in the developing world, is often metastatic and treatment resistant with no standard treatment protocol. Our laboratory pioneered the patient-derived orthotopic xenograft (PDOX) nude mouse model with the technique of surgical orthotopic implantation (SOI). Unlike subcutaneous transplant patient-derived xenograft (PDX) models, PDOX models metastasize. Most importantly, the metastasis pattern correlates to the patient. In the present report, we describe the development of a PDOX model of HER-2-positive cervical cancer. Metastasis after SOI in nude mice included peritoneal dissemination, liver metastasis, lung metastasis as well as lymph node metastasis reflecting the metastatic pattern in the donor patient. Metastasis was detected in 4 of 6 nude mice with primary tumors. Primary tumors and metastases in the nude mice had histological structures similar to the original tumor and were stained by an anti-HER-2 antibody in the same pattern as the patient's cancer. The metastatic pattern, histology and HER-2 tumor expression of the patient were thus preserved in the PDOX model. In contrast, subcutaneous transplantation of the patient's cervical tumors resulted in primary growth but not metastasis.

Patient-derived orthotopic xenograft (PDOX) nude mouse model of soft-tissue sarcoma more closely mimics the patient behavior in contrast to the subcutaneous ectopic model.

AIM: Soft-tissue sarcomas are a group of rare mesenchymal carcinomas that include approximately 50 histological types, and account for 1% of all adult cancer cases. The yearly incidence of soft-tissue sarcomas in the USA is approximately 11,280 cases, with an overall mortality of 3,900 deaths per year. MATERIALS AND METHODS: In this study, we established a patient-derived orthotopic xenograft (PDOX) from a patient with a soft-tissue sarcoma of the retroperitoneum in nude mice and compared it to a subcutaneous patient-derived model of the same tumor for histology. RESULTS: In the PDOX model, a bulky tumor grew in the left retroperitoneum in the same manner as the patient's tumor. Upon histological examination, the majority of the PDOX tissue section comprised sarcomatous high-grade spindle cells of varying sizes, similar to the original patient tumor. In contrast, the majority of the subcutaneously-implanted tumor comprised round to oval cells. CONCLUSION: These results indicate that the PDOX recapitulated the histology of the original tumor more than the subcutaneous model.

Specific tumor labeling enhanced by polyethylene glycol linkage of near infrared dyes conjugated to a chimeric anti-carcinoembryonic antigen antibody in a nude mouse model of human pancreatic cancer.

Labeling of metastatic tumors can aid in their staging and resection of cancer. Near infrared (NIR) dyes have been used in the clinic for tumor labeling. However, there can be a nonspecific uptake of dye by the liver, lungs, and lymph nodes, which hinders detection of metastasis. In order to overcome these problems, we have used two NIR dyes (DyLight 650 and 750) conjugated to a chimeric anti-carcinoembryonic antigen antibody to evaluate how polyethylene glycol linkage (PEGylation) can improve specific tumor labeling in a nude mouse model of human pancreatic cancer. The conjugated PEGylated and non-PEGylated DyLight 650 and 750 dyes were injected intravenously into non-tumor-bearing nude mice. Serum samples were collected at various time points in order to determine serum concentrations and elimination kinetics. Conjugated PEGylated dyes had significantly higher serum dye concentrations than non-PEGylated dyes (p=0.005 for the 650 dyes and p<0.001 for the 750 dyes). Human pancreatic tumors subcutaneously implanted into nude mice were labeled with antibody-dye conjugates and serially imaged. Labeling with conjugated PEGylated dyes resulted in significantly brighter tumors compared to the non-PEGylated dyes (p<0.001 for the 650 dyes; p=0.01 for 750 dyes). PEGylation of the NIR dyes also decreased their accumulation in lymph nodes, liver, and lung. These results demonstrate enhanced selective tumor labeling by PEGylation of dyes conjugated to a tumor-specific antibody, suggesting their future clinical use in fluorescence-guided surgery.

Polyethylene glycol (PEG) linked to near infrared (NIR) dyes conjugated to chimeric anti-carcinoembryonic antigen (CEA) antibody enhances imaging of liver metastases in a nude-mouse model of human colon cancer.

We report here that polyethylene glycol (PEG) linked to near infrared dyes conjugated to chimeric mouse-human anti-carcinoembryonic antigen (CEA) antibody greatly improves imaging of liver metastases in a nude mouse model of colon-cancer experimental metastases. PEGylated and non-PEGylated DyLight 650 and 750 dyes were conjugated to the chimeric anti-CEA antibody. The dyes were initially injected intravenously into nude mice without tumors. Tissue biodistribution was determined by tissue sonication and analyzing tissue dye concentration profiles over time. PEGylated dyes had significantly lower accumulation in the liver (p = 0.03 for the 650 dyes; p = 0.002 for the 750 dyes) compared to non-PEGylated dyes. In an experimental liver metastasis model of HT-29 colon cancer, PEGylated dyes conjugated to the anti-CEA antibody showed good labeling of metastatic tumors with high contrast between normal and malignant tissue which was not possible with the non-PEGylated dyes since there was so much non-specific accumulation in the liver. PEGylation of the DyLight 650 and 750 NIR dyes significantly altered tissue biodistribution, allowing brighter tissue labeling, decreased accumulation in normal organs, particularly the liver. This enabled high fidelity and high contrast imaging of liver metastases.

Fluorescence-guided surgery in combination with UVC irradiation cures metastatic human pancreatic cancer in orthotopic mouse models.

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.