Survival In Orthotopic Mouse Models Research Articles

HGG-41. COMBINATORIAL BH3-MIMETIC STRATEGY FOR OVERCOMING RADIORESISTANCE IN PEDIATRIC HIGH-GRADE GLIOMA

Abstract BACKGROUND High-grade gliomas (HGGs) are a leading cause of cancer-associated death in children. Radiation therapy (RT) continues to be the only standard-of-care treatment across HGG subtypes, but disease frequently recurs following only a transient response. We have recently identified that HGGs utilize the pro-survival BCL-2 family of proteins to evade cell death after radiation, and we demonstrated that effective inhibition of BCL-2 with the CNS-penetrant drug venetoclax could be utilized to disrupt this resistance and augment radiation-induced cell killing. While this treatment significantly prolonged survival in orthotopic mouse models of pediatric HGG, tumors invariably developed resistance to single-agent venetoclax and recurred. METHODS We profiled tumors from venetoclax-resistant animals for alternate BCL-2 family binding. We then assessed susceptibility to MCL1 inhibition in venetoclax-treated or treatment naïve culture models. Synergy was tested in vitro, and mitochondrial ROS production and induction of apoptosis was assessed using the MCL1-specific agent S63845. Finally, venetoclax and S63845 were tested in combination following fractionated radiotherapy in orthotopic models of DIPG. RESULTS MCL1 is an acquired dependency following treatment with RT + venetoclax. S63845 synergizes with venetoclax following RT to drive mitochondrial ROS production and apoptosis. The combination of venetoclax and S63845 significantly prolongs survival in xenograft models of DIPG. CONCLUSIONS Combinatorial targeting with BH3 mimetics augments radiation-induced cell killing and may open new therapeutic avenues for pediatric HGG.

ATRT-01. PARP INHIBITION AS A THERAPEUTIC TARGET IN ATRT

Abstract Atypical teratoid rhabdoid tumors (ATRTs) are highly aggressive pediatric brain tumors with poor survival. The available treatments rely on toxic chemotherapy and radiotherapy, which alone can cause poor outcomes for young patients. Poly (ADP-ribose) polymerases (PARP), multifunctional enzymes which play an important role in DNA damage repair and genome stability have emerged as a new target in cancer therapy. An FDA approved drug screen revealed that Rucaparib, a PARP inhibitor, is important for ATRT cell growth.In this study we investigated the effect of Rucaparib treatment in ATRT. Using MTS and colony formation assays we found that Rucaparib treatment decreased ATRT cell growth and inhibited clonogenic potential of ATRT cells. Flow cytometry and Western blot analysis showed that Rucaparib treatment led to cell cycle arrest and apoptosis. Moreover, Rucaparib treatment led to DNA damage accumulation as seen by increased expression of yH2AX by immunofluorescence. In vivo, Rucaparib treatment significantly decreased tumor growth and prolonged survival in orthotopic mouse models. Furthermore, Immunohistochemistry revealed an increased number of P53 and Caspase3positive cells in the Rucaparib treatment group, confirming the induction of apoptosis in vivo. Furthermore, Rucaparib pretreatment sensitizes ATRT cells to radiation and significantly increased survival of xenograft-bearing mice. Thus, we demonstrated that Rucaparib has potential to be a new therapeutic strategy for ATRT as shown by its ability to decrease ATRT tumor growth both in vitro and in vivo.

Acetyl-Coenzyme A Synthetase 2 Potentiates Macropinocytosis and Muscle Wasting Through Metabolic Reprogramming in Pancreatic Cancer

Rapid deconditioning, also called cachexia, and metabolic reprogramming are two hallmarks of pancreatic cancer. Acetyl-coenzyme A synthetase short-chain family member 2 (ACSS2) is an acetyl-enzyme A synthetase that contributes to lipid synthesis and epigenetic reprogramming. However, the role of ACSS2 on the nonselective macropinocytosis and cancer cachexia in pancreatic cancer remains elusive. In this study, we demonstrate that ACSS2 potentiates macropinocytosis and muscle wasting through metabolic reprogramming in pancreatic cancer. Clinical significance of ACSS2 was analyzed using samples from patients with pancreatic cancer. ACSS2-knockout cells were established using the clustered regularly interspaced short palindromic repeats-associated protein 9 system. Single-cell RNA sequencing data from genetically engineered mouse models was analyzed. The macropinocytotic index was evaluated by dextran uptake assay. Chromatin immunoprecipitation assay was performed to validate transcriptional activation. ACSS2-mediated tumor progression and muscle wasting were examined in orthotopic xenograft models. Metabolic stress induced ACSS2 expression, which is associated with worse prognosis in pancreatic cancer. ACSS2 knockout significantly suppressed cell proliferation in 2-dimensional and 3-dimensional models. Macropinocytosis-associated genes are upregulated in tumor tissues and are correlated with worse prognosis. ACSS2 knockout inhibited macropinocytosis. We identified Zrt- and Irt-like protein 4 (ZIP4) as a downstream target of ACSS2, and knockdown ofZIP4 reversed ACSS2-induced macropinocytosis. ACSS2 upregulated ZIP4 through ETV4-mediated transcriptional activation. ZIP4 induces macropinocytosis through cyclic adenosine monophosphate response element-binding protein-activated syndecan 1 (SDC1) and dynamin 2 (DNM2). Meanwhile, ZIP4 drives muscle wasting and cachexia via glycogen synthase kinase-β (GSK3β)-mediated secretion of tumor necrosis factor superfamily member 10 (TRAIL or TNFSF10). ACSS2 knockout attenuated muscle wasting andextended survival in orthotopic mouse models. ACSS2-mediated metabolic reprogramming activates the ZIP4 pathway, and promotes macropinocytosis via SDC1/DNM2 and drives muscle wasting through the GSK3β/TRAIL axis, which potentially provides additional nutrients for macropinocytosis in pancreatic cancer.

Non-invasive transferrin targeted nanovesicles sensitize resistant glioblastoma multiforme tumors and improve survival in orthotopic mouse models.

The blood-brain barrier (BBB) and tumor heterogeneity have resulted in abysmally poor clinical outcomes in glioblastoma (GBM) with the standard therapeutic regimen. Despite several anti-glioma drug delivery strategies, the lack of adequate chemotherapeutic bioavailability in gliomas has led to a suboptimal therapeutic gain in terms of improvement in survival and increased systemic toxicities. This has paved the way for designing highly specific and non-invasive drug delivery approaches for treating GBM. The intranasal (IN) route is one such delivery strategy that has the potential to reach the brain parenchyma by circumventing the BBB. We recently showed that in situ hydrogel embedded with miltefosine (HePc, proapoptotic anti-tumor agent) and temozolomide (TMZ, DNA methylating agent) loaded targeted nanovesicles prevented tumor relapses in orthotopic GBM mouse models. In this study, we specifically investigated the potential of a non-invasive IN route of TMZ delivered from lipid nanovesicles (LNs) decorated with surface transferrin (Tf) and co-encapsulated with HePc to reach the brain by circumventing the BBB in glioma bearing mice. The targeted nanovesicles (228.3 ± 10 nm, -41.7 ± 4 mV) exhibited mucoadhesiveness with 2% w/v mucin suggesting their potential to increase brain drug bioavailability after IN administration. The optimized TLNs had controlled, tunable and significantly different release kinetics in simulated cerebrospinal fluid and simulated nasal fluid demonstrating efficient release of the payload upon reaching the brain. Drug synergy (combination index, 0.7) showed a 6.4-fold enhanced cytotoxicity against resistant U87MG cells compared to free drugs. In vivo gamma scintigraphy of 99mTc labeled LNs showed 500- and 280-fold increased brain concentration post 18 h of treatment. The efficacy of the TLNs increased by 1.8-fold in terms of survival of tumor-bearing mice compared to free drugs. These findings suggested that targeted drug synergy has the potential to intranasally deliver a high therapeutic dose of the chemotherapy agent (TMZ) and could serve as a platform for future clinical application.

DUSP6 regulates radiosensitivity in glioblastoma by modulating the recruitment of phosphorylated DNAPKcs at DNA double-strand breaks.

Glioblastoma (GBM) has poor median survival due to its resistance to chemoradiotherapy, which results in tumor recurrence. Recurrent GBMs currently lack effective treatments. DUSP6 is known to be pro-tumorigenic and is upregulated in GBM. We show that DUSP6 expression is significantly higher in recurrent GBM patient biopsies compared to expression levels in primary GBM biopsies. Importantly, although it has been reported to be a cytoplasmic protein, we found nuclear localization of DUSP6 in primary and recurrent patient samples and in parent and relapse populations of GBM cell lines generated from an in vitro radiation survival model. DUSP6 inhibition using BCI resulted in decreased proliferation and clonogenic survival of parent and relapse cells. Pharmacological or genetic inhibition of DUSP6 catalytic activity radiosensitized primary and, importantly, relapse GBM cells by inhibiting the recruitment of phosphorylated DNAPKcs (also known as PRKDC), subsequently downregulating the recruitment of phosphorylated histone H2AX (γH2AX) and 53BP1 (also known as TP53BP1). This resulted in decreased cell survival and prolonged growth arrest upon irradiation in vitro and significantly increased the progression-free survival in orthotopic mouse models of GBM. Our study highlights a non-canonical function of DUSP6, emphasizing the potential application of DUSP6 inhibitors in the treatment of recurrent GBM.

Targeting human leukocyte antigen G with chimeric antigen receptors of natural killer cells convert immunosuppression to ablate solid tumors

BackgroundImmunotherapy against solid tumors has long been hampered by the development of immunosuppressive tumor microenvironment, and the lack of a specific tumor-associated antigen that could be targeted in different kinds...

Unbiased Metabolic Profiling Predicts Sensitivity of High MYC-Expressing Atypical Teratoid/Rhabdoid Tumors to Glutamine Inhibition with 6-Diazo-5-Oxo-L-Norleucine.

Atypical teratoid/rhabdoid tumors (AT/RT) are aggressive infantile brain tumors with poor survival. Recent advancements have highlighted significant molecular heterogeneity in AT/RT with an aggressive subgroup featuring overexpression of the MYC proto-oncogene. We perform the first comprehensive metabolic profiling of patient-derived AT/RT cell lines to identify therapeutic susceptibilities in high MYC-expressing AT/RT. Metabolites were extracted from AT/RT cell lines and separated in ultra-high performance liquid chromatography mass spectrometry. Glutamine metabolic inhibition with 6-diazo-5-oxo-L-norleucine (DON) was tested with growth and cell death assays and survival studies in orthotopic mouse models of AT/RT. Metabolic flux analysis was completed to identify combination therapies to act synergistically to improve survival in high MYC AT/RT. Unbiased metabolic profiling of AT/RT cell models identified a unique dependence of high MYC AT/RT on glutamine for survival. The glutamine analogue, DON, selectively targeted high MYC cell lines, slowing cell growth, inducing apoptosis, and extending survival in orthotopic mouse models of AT/RT. Metabolic flux experiments with isotopically labeled glutamine revealed DON inhibition of glutathione (GSH) synthesis. DON combined with carboplatin further slowed cell growth, induced apoptosis, and extended survival in orthotopic mouse models of high MYC AT/RT. Unbiased metabolic profiling of AT/RT identified susceptibility of high MYC AT/RT to glutamine metabolic inhibition with DON therapy. DON inhibited glutamine-dependent synthesis of GSH and synergized with carboplatin to extend survival in high MYC AT/RT. These findings can rapidly translate into new clinical trials to improve survival in high MYC AT/RT.

Abstract 5267: Unbiased metabolic profiling of atypical teratoid/rhabdoid tumors predicts sensitivity to the glutamine metabolic inhibitor 6-diazo-5-oxo-L-norleucine

Abstract Atypical teratoid rhabdoid tumors (AT/RT) are deadly tumors of infancy in need of new, targeted therapies. Molecular analyses have revealed 3 epigenetically distinct subgroups of AT/RT. High MYC-expressing tumors are a particularly aggressive subgroup, with a 5-year median survival of 18.5%. MYC is difficult to directly target given large, flat, featureless protein-protein binding sites. We performed the first unbiased metabolic profile of AT/RT cell models by high-performance liquid chromatography-mass spectrometry. This study revealed that high MYC-expressing AT/RT have a unique metabolic profile (Partial Least Squares-Discriminant Analysis). Pathway analysis highlights a dependence on glutamine metabolism in high-MYC expressing AT/RT. High MYC-expressing cell lines grow poorly in glutamine-free media compared to low-MYC cell lines (MTS assay, glutamine-free media vs normal media). Due to this dependence on glutamine metabolism, we hypothesized that high-MYC expressing AT/RT would be especially sensitive to glutamine metabolic inhibitors. We show that the glutamine analogue, 6-diazo-5-oxo-L-norleucine (DON) slows high-MYC expressing AT/RT cell growth, induces high rates of apoptosis, and improves survival in orthotopic mouse models of high-MYC expressing AT/RT (p =0.0027 by log-rank test). In contrast, low-MYC expressing models are relatively insensitive to DON. In uniformly labeled glutamine metabolic analyses of AT/RT cells, DON treatment led to depletion of glutathione levels by preventing the production of glutamate. DON treatment synergized with carboplatin to kill AT/RT cells in vitro and extend the life of mice bearing AT/RT orthotopic xenografts (p< 0.001 by log rank test). We aim to translate these findings into a new clinical trial to improve survival in this deadly disease. Citation Format: Sabrina Z. Wang, Brad Poore, Jesse Alt, Antoinette Price, Sariah Allen, Brent Orr, Rana Rais, Barbara Slusher, Charles Eberhart, Eric H. Raabe, Jeffrey H. Rubens. Unbiased metabolic profiling of atypical teratoid/rhabdoid tumors predicts sensitivity to the glutamine metabolic inhibitor 6-diazo-5-oxo-L-norleucine [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 5267.

Orally Bioavailable and Blood-Brain Barrier-Penetrating ATM Inhibitor (AZ32) Radiosensitizes Intracranial Gliomas in Mice.

Inhibition of ataxia-telangiectasia mutated (ATM) during radiotherapy of glioblastoma multiforme (GBM) may improve tumor control by short-circuiting the response to radiation-induced DNA damage. A major impediment for clinical implementation is that current inhibitors have limited central nervous system (CNS) bioavailability; thus, the goal was to identify ATM inhibitors (ATMi) with improved CNS penetration. Drug screens and refinement of lead compounds identified AZ31 and AZ32. The compounds were then tested in vivo for efficacy and impact on tumor and healthy brain. Both AZ31 and AZ32 blocked the DNA damage response and radiosensitized GBM cells in vitro AZ32, with enhanced blood-brain barrier (BBB) penetration, was highly efficient in vivo as radiosensitizer in syngeneic and human, orthotopic mouse glioma model compared with AZ31. Furthermore, human glioma cell lines expressing mutant p53 or having checkpoint-defective mutations were particularly sensitive to ATMi radiosensitization. The mechanism for this p53 effect involves a propensity to undergo mitotic catastrophe relative to cells with wild-type p53. In vivo, apoptosis was >6-fold higher in tumor relative to healthy brain after exposure to AZ32 and low-dose radiation. AZ32 is the first ATMi with oral bioavailability shown to radiosensitize glioma and improve survival in orthotopic mouse models. These findings support the development of a clinical-grade, BBB-penetrating ATMi for the treatment of GBM. Importantly, because many GBMs have defective p53 signaling, the use of an ATMi concurrent with standard radiotherapy is expected to be cancer-specific, increase the therapeutic ratio, and maintain full therapeutic effect at lower radiation doses. Mol Cancer Ther; 17(8); 1637-47. ©2018 AACR.

Abstract 216: Pancreatic cancer fluorescence-­guided surgery with a fluorophore­-conjugated antibody to carcinoembryonic antigen (CEA) improves surgical resection and increases disease-free and overall survival in orthotopic mouse models

Abstract We established nude­ mouse models of human pancreatic cancer with surgical orthotopic implantation of the human BxPC­3 pancreatic cancer for fluorescence-guided surgery (FGS). After 2 weeks, mice then underwent bright-­light surgery (BLS) or FGS 24 hours after intravenous injection of anti CEA­-Alexa Fluor 488. Completeness of resection was assessed from postoperative imaging. Mice were followed postoperatively until premorbid to determine disease-free survival (DFS) and overall survival (OS). Complete resection was achieved in 92% of mice in the FGS group compared to 45.5% in the BLS group (p = 0.001). FGS resulted in a smaller postoperative tumor burden (p = 0.01). Cure rates with FGS compared to BLS improved from 4.5 to 40%, respectively (p = 0.01), and 1­year postoperative survival rates increased from 0% with BLS to 28% with FGS (p = 0.01). Median DFS increased from 5 weeks with BLS to 11 weeks with FGS (p = 0.0003). Median OS increased from 13.5 weeks with BLS to 22 weeks with FGS (p = 0.001). FGS resulted in greater cure rates and longer DFS and OS using a fluorophore-­conjugated anti ­CEA antibody. The present results demonstrate that FGS has potential to improve the surgical treatment of pancreatic cancer. Citation Format: Cristina A. Metildi, Sharmeela Kaushal, George A. Luiken, Robert M. Hoffman, Michael Bouvet. Pancreatic cancer fluorescence-­guided surgery with a fluorophore­-conjugated antibody to carcinoembryonic antigen (CEA) improves surgical resection and increases disease-free and overall survival in orthotopic mouse models. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 216. doi:10.1158/1538-7445.AM2015-216

Abstract 3726: Inhibition of MET overcomes invasive resistance to Bevacizumab and prolongs survival in orthotopic mouse models of glioblastoma multiforme

Abstract Glioblastoma multiforme (GBM) is the most malignant brain tumor. Despite recent therapeutic improvements, the median overall survival remains poor. Due to its high grade of vascularity, GBM is an ideal candidate for anti-angiogenic therapy. In 2009, US Food and Drug Administration granted accelerated approval for Bevacizumab, a humanized monoclonal antibody directed against VEGF-A, for patients with recurrent disease. Its use in newly diagnosed GBM is currently being evaluated. In the recurrent setting, Bevacizumab provides a transient improvement in PFS that unfortunately does not translate into increased OS. In fact, most tumors become resistant to Bevacizumab and patients invariably experience tumor regrowth. Moreover, a large number of recurrent tumors display an infiltrative and invasive phenotype, thus leading to extremely aggressive tumor growth. Understanding the molecular mechanisms underlying ‘invasive resistance’ to Bevacizumab represents a key step towards the development of improved therapeutic strategies for GBM. We hypothesized that Bevacizumab-induced tumor hypoxia could be responsible for the activation of pro-invasive pathways. We tested this hypothesis using different human GBM cell lines, both in vitro and in orthotopic mouse models of GBM. In vitro, hypoxia promoted increased expression of MET, the high affinity receptor for Hepatocyte Growth Factor(HGF), in all GBM cells analyzed. Increased MET expression resulted in higher sensitivity to HGF stimulation and in enhanced invasiveness. Higher MET levels were not due to transcriptional activation of c-met, but rather to post-transcriptional redistribution of the MET protein from the cytoplasm to the plasma membrane. In vivo, Bevacizumab did marginally improve survival of mice implanted orthotopically with human GBM tumors, but exacerbated tumor hypoxia and resulted in MET activation. Histological analysis of Bevacizumab-treated tumors revealed a highly invasive and infiltrative phenotype. Combined treatment with Bevacizumab and JNJ-38877605, a highly selective, orally available small molecule MET tyrosine kinase inhibitor, significantly prolonged mouse survival compared to both placebo and Bevacizumab alone. Histological examination showed no infiltrative phenotype in the combined treatment arm. Treatment with JNJ-38877605 alone also improved mouse survival in both tumors displaying HGF-MET autocrine stimulation (implanted in nude mice) and in tumors requiring paracrine HGF stimulation (implanted in human HGF knock-in SCID mice). These results unveil a new mechanism by which GBM may become resistant to Bevacizumab, generating proof-of-concept for conducting clinical trials using angiogenesis inhibitors in combination with MET inhibitors. Citation Format: Manuela Cazzanti, Paolo Michieli. Inhibition of MET overcomes invasive resistance to Bevacizumab and prolongs survival in orthotopic mouse models of glioblastoma multiforme. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3726. doi:10.1158/1538-7445.AM2014-3726

Fluorescence-guided Surgery with a Fluorophore-conjugated Antibody to Carcinoembryonic Antigen (CEA), that Highlights the Tumor, Improves Surgical Resection and Increases Survival in Orthotopic Mouse Models of Human Pancreatic Cancer

We have developed a method of distinguishing normal tissue from pancreatic cancer in vivo using fluorophore-conjugated antibody to carcinoembryonic antigen (CEA). The objective of this study was to evaluate whether fluorescence-guided surgery (FGS) with a fluorophore-conjugated antibody to CEA, to highlight the tumor, can improve surgical resection and increase disease-free survival (DFS) and overall survival (OS) in orthotopic mouse models of human pancreatic cancer. We established nude-mouse models of human pancreatic cancer with surgical orthotopic implantation of the human BxPC-3 pancreatic cancer. Orthotopic tumors were allowed to develop for 2 weeks. Mice then underwent bright-light surgery (BLS) or FGS 24 h after intravenous injection of anti-CEA-Alexa Fluor 488. Completeness of resection was assessed from postoperative imaging. Mice were followed postoperatively until premorbid to determine DFS and OS. Complete resection was achieved in 92 % of mice in the FGS group compared to 45.5 % in the BLS group (p = 0.001). FGS resulted in a smaller postoperative tumor burden (p = 0.01). Cure rates with FGS compared to BLS improved from 4.5 to 40 %, respectively (p = 0.01), and 1-year postoperative survival rates increased from 0 % with BLS to 28 % with FGS (p = 0.01). Median DFS increased from 5 weeks with BLS to 11 weeks with FGS (p = 0.0003). Median OS increased from 13.5 weeks with BLS to 22 weeks with FGS (p = 0.001). FGS resulted in greater cure rates and longer DFS and OS using a fluorophore-conjugated anti-CEA antibody. FGS has potential to improve the surgical treatment of pancreatic cancer.

Abstract 726: Fluorophore-conjugated antibodies improve surgical resection of pancreatic cancer leading to prolonged disease-free survival and overall survival in orthotopic mouse models.

Abstract We established orthotopic mouse models of human pancreatic cancer with fragments of BxPC-3-RFP tumor. Two weeks after implantation, mice were randomized to FGS or bright-field surgery (BS). FGS was performed 24 hrs after tail vein injection of anti-CEA-Alexa 488. Completeness of resection was assessed from pre- and postoperative images obtained with the OV-100 Small Animal Imaging System. Whole body images of mice were obtained postoperatively to assess for recurrence and mice were followed until premorbid to measure survival. We achieved a complete resection of pancreatic cancers in 92% of mice in the FGS group as compared to 58% in the BS group (p=0.002). Preoperative tumor burden was not significantly different between groups (p=0.424). However, FGS afforded a significantly smaller mean postoperative tumor burden compared to BS: 0.0004 ± SE 0.0003 mm2 vs. 0.0841 ± SE 0.027 mm2, p=0.004. On average, mice in the FGS experienced a greater reduction in tumor burden: 99.99% vs 97.72%, p=0.01. FGS reduced recurrence rates from 95% to 50% (p=0.002) and lengthened mean disease-free survival from 7 weeks to 30.5 weeks (p<0.001). The FGS group experienced longer overall survival compared to the BS group: 16.5 weeks vs. 37 weeks (p=0.001). Cure rate was improved with FGS from 5% to 50% (p=0.003). Furthermore, FGS more than doubled the one-year postoperative survival rate from 3 mice in the BLS group to 8 mice in the FGS group (p=0.005). This novel approach has potential to improve outcomes in the surgical treatment of pancreatic cancer. Survival and recurrence according to surgical mode. Surgical Mode Disease-Free Survival Overall Survival Recurrence Rate Bright-Field Surgery 7 weeks 16.5 weeks 95% Fluorescence-Guided Surgery 30.5 weeks 37 weeks 50% Citation Format: Cristina A. Metildi, Sharmeela Kaushal, Mark A. Talamini, George A. Luiken, Robert M. Hoffman, Michael Bouvet. Fluorophore-conjugated antibodies improve surgical resection of pancreatic cancer leading to prolonged disease-free survival and overall survival in orthotopic mouse models. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 726. doi:10.1158/1538-7445.AM2013-726

Fluorophore-conjugated antibodies improve surgical resection of pancreatic cancer leading to prolonged disease-free survival and overall survival in orthotopic mouse models

Fluorophore-conjugated antibodies improve surgical resection of pancreatic cancer leading to prolonged disease-free survival and overall survival in orthotopic mouse models

Abstract 375: Fluorescence-guided surgery leads to improved resection of primary pancreatic cancer and prolonged survival

Abstract The aim of this study was to determine if fluorescence-guided surgery (FGS) could improve surgical outcomes, reduce recurrence rates and improve overall survival in orthotopic mouse models of human pancreatic cancer. Orthotopic mouse models of human pancreatic cancer were established using the BxPC-3 RFP-expressing pancreatic cancer cell line in nude mice. Two weeks after implantation, the mice were randomized to undergo bright light surgery (BLS) or fluorescence-guided surgery (FGS). Pre- and postoperative images were obtained with the Olympus OV-100 Small Animal Imaging System to assess completeness of surgical resection. Whole body imaging of the mice was performed weekly in the postoperative period to assess for recurrence and follow tumor progression. Additionally, half of the mice were randomly selected to undergo 4 weeks of postoperative gemcitabine treatment. At six weeks postoperatively, or when premorbid, the mice were sacrificed and primary pancreatic tumor burden was measured using ImageJ v1.440. A more complete resection of pancreatic cancer was achieved using FGS compared to BLS: 98.9% vs 77.1%, p=0.005. Sixty-three percent of the mice undergoing BLS had evidence of gross residual disease, whereas 20% of mice undergoing FGS received a complete resection and an additional 75% of the mice were left with minimal residual disease (p=0.0001). At six weeks, the primary pancreatic tumor burden was significantly less with FGS compared to BLS: 19.341 ± 5.26 mm2 vs. 6.194 ± 3.61 mm2, p=0.048. In a pilot survival study, FGS alone was associated with a decreased risk of tumor recurrence (HR=0.093, 95% CI 0.013-0.645), and mean overall survival was lengthened from 18.5 weeks to 28.2 weeks. The addition of adjuvant gemcitabine (GEM) to FGS further lengthened mean overall survival to 42.75 weeks (p=0.019). Three of the four mice in the FGS with adjuvant gemcitabine group were alive at 12 months postoperatively and all of the mice (n=4) were free of tumor at time of sacrifice. In this study, we achieved improved surgical outcomes in primary pancreatic cancer under fluorescence-guidance. FGS afforded a more complete resection of primary tumor and improved disease-free survival and overall survival. The combination of FGS and GEM lengthened disease-free survival and improved overall survival. This novel approach has potential to improve outcomes in the surgical treatment of pancreatic cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 375. doi:1538-7445.AM2012-375