Surgeon-Dependent Variability in Cost of Gastrointestinal Operations in a Single Cancer Center

INTRODUCTION

Cancer operations are increasingly utilizing specialized equipment and technology. Related costs are often not known to the responsible surgeon. We seek to evaluate cost aspects of care episodes attributable to the surgeon's management decisions.

METHODS

Financial cost data in a tertiary academic cancer center were queried over 3 y. Consecutive patients undergoing gastrointestinal operations followed by inpatient admission of two or more days were included, excluding patients with 40+ d admissions. Analysis of variance, Kruskal-Wallis, and multiple regression statistics were utilized.

RESULTS

The study population included 1540 patients: 54% men and 46% women, with a median age of 64 y (range 15-95). Eight surgeons conducted major (82%) and minor (18%) operations, with a minimally invasive surgical approach in 60.4%. Procedures included colorectal (37%), pancreatic (19%), esophagogastric (18%), hepatobiliary (18%), and small bowel resections (8%). Total direct costs differed between surgeons with an analysis of variance coefficient range between -$3265 and +$6163 (P < 0.001). Surgeons' cost differences were observed for central medical supply, operating room (OR) supply, total OR, inpatient room, laboratory, pharmacy, supportive care (P < 0.001), and radiology costs (P < 0.02). OR supply cost was the dominant consistent domain with significant differences between surgeons in all case subcategories. When controlled for case category and minimally invasive surgical approach, multiple regression showed the most significant variations between surgeons in ORs, medical supply, and nutrition costs (P < 0.001), followed by laboratory costs (P < 0.01). Top OR supply costs were staplers and energy devices.

CONCLUSIONS

Even in a highly subspecialized surgical environment, surgeons' variable utilization of ORs and medical supplies is strongly linked to variations in care-related costs. Specific queries into supply items should reduce costs and optimize value generated.

Perioperative Chemotherapy is Associated with Superior Overall Survival in Patients with Synchronous Colorectal Liver Metastases

BACKGROUND

The sequence of localized and systemic treatment for colorectal liver metastases (CRLM) remains debated. Our objective is to analyze the effect of treatment sequence on overall survival (OS) in patients with CRLM using a large cancer database.

PATIENTS AND METHODS

The national cancer database (NCDB) was utilized to identify patients with stage IV colorectal cancer (CRC) diagnosed between 2004 and 2016. OS was analyzed using standard univariate and multivariate methods.

RESULTS

We identified 72,376 patients with synchronous CRLM, of whom 43,039 had liver-only metastases. Patients with liver-only CRLM had a median OS of 18.9 months, versus those with CRLM plus extrahepatic sites (11.3 months). In patients with liver-only CRLM, resection of both the primary and metastatic site was associated with median OS 38.9 months versus 30.2 months after resection of the metastatic site alone, and resection of the primary tumor alone (22.3 months, all p < 0.001). Receipt of perioperative chemotherapy correlated with a median OS of 44.7 months versus preoperative chemotherapy only (38.4 months) or postoperative chemotherapy only (27.9 months, all p < 0.001). Patients who received chemotherapy alone had a median OS of 16.4 months versus those who underwent resection without chemotherapy (9.5 months, p < 0.001).

CONCLUSIONS

This study reveals a correlation between perioperative chemotherapy and superior OS in patients with liver-only CRLM, and shows that resection of the metastatic site was linked to better OS. Despite obvious cohort heterogeneity, the data can support a resection approach with additional, preferably peri- or preoperative systemic therapy for patients with CRLM.

Low incisional hernia incidence using a large-bite, low-tension technique for celiotomy closure

Background

Incisional herniae (IH) are reported in 5->20 % of patients undergoing open celiotomy, and can be linked to closure technique. The STITCH randomized trial favors a small bite technique for midline celiotomy closure with a 1-year IH rate of 13 % over larger bites (23 %).

Methods

A continuous musculofascial mass closure with absorbable looped #1 PDS suture with 2-cm bite size was used for all open celiotomies. IH frequency and associated clinicopathologic factors were retrospectively analyzed from prospective data in 336 consecutive patients undergoing visceral resections by a single surgeon.

Results

The study population included 192 men and 144 women, 81 % of whom had a cancer diagnosis, who underwent hepatobiliary, pancreatic, gastroesophageal, and colorectal resections, or a combination. The majority of patients (84 %) had subcostal incisions, and 10 % received a midline incision. At a median follow-up of 19.5 months, the overall IH rate was 3.3 %. Hernia rates were 2.5 % for subcostal margin, 2.9 % for midline, and 5.5 % for other incisions (p = 0.006). Median time to hernia detection was 492 days. Factors associated with IH were increased weight, abdominal depth/girth, male sex, spleen size, visceral fat, and body height (p ≤ 0.04 for all), but not type of resection, prior operations, underlying diagnosis, weight loss, adjuvant chemotherapy or radiation, incision length or suture to incision ratio.

Conclusions

The described technique leads to a low IH rate of <3 % in subcostal or midline incisions, and can be recommended for routine use. The observed results appear superior to those of the STITCH trial, even for the smaller midline incision cohort.

Enhancing gastric cancer conventional chemotherapy effects by triple angiokinase inhibitor nintedanib in preclinical models

Background

Gastric adenocarcinoma (GAC) is the fourth leading cause of cancer death worldwide. Systemic chemotherapy is a preferred treatment option for advanced and recurrent GAC, but response rates and survival prolongation remain limited. Tumor angiogenesis plays a critical role in GAC growth, invasion and metastasis. We investigated the antitumor efficacy of nintedanib, a potent triple angiokinase inhibitor for VEGFR-1/2/3, PDGFR-α/β and FGFR-1/2/3, alone or in combination with chemotherapy, in preclinical models of GAC.

Methods

Animal survival studies were performed in peritoneal dissemination xenografts in NOD/SCID mice using human GAC cell lines MKN-45 and KATO-III. Tumor growth inhibition studies were performed in subcutaneous xenografts in NOD/SCID mice using human GAC cell lines MKN-45 and SNU-5. The mechanistic evaluation involved Immunohistochemistry analyses in tumor tissues obtained from subcutaneous xenografts. In vitro cell viability assays were performed using a colorimetric WST-1 reagent.

Results

In MKN-45 GAC cell-derived peritoneal dissemination xenografts, animal survival was improved by nintedanib (33%), docetaxel (100%) and irinotecan (181%), while oxaliplatin, 5-FU and epirubicin had no effect. The addition of nintedanib to docetaxel (157%) or irinotecan (214%) led to a further extension in animal survival. In KATO-III GAC cell-derived xenografts carrying FGFR2 gene amplification, nintedanib extended survival by 209%. Again, the addition of nintedanib further enhanced the animal survival benefits of docetaxel (273%) and irinotecan (332%). In MKN-45 subcutaneous xenografts, nintedanib, epirubicin, docetaxel and irinotecan reduced tumor growth (range: 68-87%), while 5-FU and oxaliplatin had a smaller effect (40%). Nintedanib addition to all chemotherapeutics demonstrated a further reduction in tumor growth. Subcutaneous tumor analysis revealed that nintedanib attenuated tumor cell proliferation, reduced tumor vasculature and increased tumor cell death.

Conclusion

Nintedanib showed notable antitumor efficacy and significantly improved taxane or irinotecan chemotherapy responses. These findings indicate that nintedanib, alone and in combination with a taxane or irinotecan, has the potential for improving clinical GAC therapy.

Augmenting Experimental Gastric Cancer Activity of Irinotecan through Liposomal Formulation and Antiangiogenic Combination Therapy

Gastric adenocarcinoma (GAC) is the third most common cause of cancer-related deaths worldwide. Combination chemotherapy remains the standard treatment for advanced GAC. Liposomal irinotecan (nal-IRI) has improved pharmacokinetics (PK) and drug biodistribution compared with irinotecan (IRI, CPT-11). Angiogenesis plays a crucial role in the progression and metastasis of GAC. We evaluated the antitumor efficacy of nal-IRI in combination with novel antiangiogenic agents in GAC mouse models. Animal survival studies were performed in peritoneal dissemination xenografts. Tumor growth and PK studies were performed in subcutaneous xenografts. Compared with controls, extension in animal survival by nal-IRI and IRI was >156% and >94%, respectively. The addition of nintedanib or DC101 extended nal-IRI response by 13% and 15%, and IRI response by 37% and 31% (MKN-45 xenografts); nal-IRI response by 11% and 3%, and IRI response by 16% and 40% (KATO-III xenografts). Retardation of tumor growth was greater with nal-IRI (92%) than IRI (71%). Nintedanib and DC101 addition tend to augment nal-IRI or IRI response in this model. The addition of antiangiogenic agents enhanced tumor cell proliferation inhibition effects of nal-IRI or IRI. The tumor vasculature was decreased by nintedanib (65%) and DC101 (58%), while nal-IRI and IRI alone showed no effect. PK characterization in GAC xenografts demonstrated that compared with IRI, nal-IRI treatment groups had higher retention, circulation time, and tumor levels of CPT-11 and its active metabolite SN-38. These findings indicate that nal-IRI, alone and in combination with antiangiogenic agents, has the potential for improving clinical GAC therapy.

Abstract 1052: Augmentation of standard chemotherapy response by inhibition of Aurora kinase A in preclinical models of pancreatic cancer

Background: The prognosis of pancreatic ductal adenocarcinoma (PDAC) is very poor with a 5-year survival rate of 8%. Current standard chemotherapeutic treatment nab-paclitaxel (NPT) plus gemcitabine (Gem) has been able to give an average prognosis of 8.5 months after detection. Aurora Kinase A (AURKA), an enzyme responsible for the regulation of cytokinesis, is mutated in over 55% of PDAC. Increased expression of AURKA inhibits metabolic stress-induced autophagy, thus promoting cell survival. Additionally, amplification of AURKA has been shown to lead to taxane resistance. Through inhibition of AURKA signaling with a small-molecule inhibitor alisertib (MLN8237, ALS), we evaluated an enhancement of NPT+Gem chemotherapy response in PDAC.

Methods: In vitro cell proliferation was evaluated in PDAC-associated cell lines by WST-1 assay. Protein expression was measured by Immunoblot analysis. Tumor growth and survival studies were performed using human PDAC cells AsPC-1 in NOD/SCID mice. Intratumoral mechanism of action was determined by IHC and Immunoblot analysis.

Results: In AsPC-1 subcutaneous xenografts, chemotherapy regimen (NPT+Gem) and alisertib inhibited tumor growth while their combination exhibited an additive effect. The increase in tumor size was 255 mm3 in controls, 105 mm3 after NPT+Gem, 133 mm3 after ALS and 38 mm3 after NPT+Gem+ALS treatment. In peritoneal dissemination xenografts, animal survival was 23 days in controls that was increased by NPT+Gem (41 days, 78% increase), ALS (25 days, 9% increase) and NPT+Gem+ALS exhibited an additive effect (49 days, 113% increase). NPT+Gem and ALS effect on tumor cell proliferation and apoptosis corresponded with subcutaneous tumor growth data. In vitro proliferation analysis of PDAC epithelial cells (AsPC-1, Panc-1), stromal cells and endothelial cells demonstrated that NPT+Gem and ALS inhibited cell proliferation and their combination treatment had an additive effect. Immunoblot analysis of PDAC cells showed increased levels of cleaved caspase-3 and cleaved PARP-1 in combination therapy pointing to increased levels of apoptosis with NPT+Gem+ALS treatment in all cell lines tested.

Conclusion: These findings demonstrate that nab-paclitaxel plus gemcitabine standard chemotherapy response can be enhanced through specific inhibition of aurora kinase A signaling by alisertib in PDAC. The data support the potential of this combinatorial therapeutic strategy for clinical PDAC therapy.

Citation Format: David Kronenberger, Margaret A. Schwarz, Md Sazzad Hassan, Urs von Holzen, Roderich E. Schwarz, Niranjan Awasthi. Augmentation of standard chemotherapy response by inhibition of Aurora kinase A in preclinical models of pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1052.

Targeted FGFR/VEGFR/PDGFR inhibition with dovitinib enhances the effects of nab-paclitaxel in preclinical gastric cancer models

Standard chemotherapy regimens for gastric adenocarcinoma (GAC) have limited efficacy and considerable toxicity profiles. Nab-paclitaxel has shown promising antitumor benefits in previous GAC preclinical studies. Dovitinib inhibits members of the receptor tyrosine kinase family including FGFR, VEGFR and PDGFR, and has exhibited antitumor effects in many solid tumors including GAC. Based on the antimitotic, antistromal and EPR effects of nab-paclitaxel, we investigated augmentation of nab-paclitaxel response by dovitinib in multiple GAC preclinical models. In MKN-45 subcutaneous xenografts, inhibition in tumor growth by nab-paclitaxel and dovitinib was 75% and 76%, respectively. Dovitinib plus nab-paclitaxel had an additive effect on tumor growth inhibition and resulted in tumor regression (85% of its original value). Dovitinib monotherapy resulted in minimal improvement in animal survival (25 days) compared to control (23 days), while nab-paclitaxel monotherapy or dovitinib plus nab-paclitaxel combination therapy led to a clinically significant lifespan extension of 83% (42 days) and 187% (66 days), respectively. IHC analysis of subcutaneous tumors exhibited reduced tumor cell proliferation and tumor vasculature by dovitinib. In vitro studies demonstrated that dovitinib and nab-paclitaxel individually reduced tumor cell proliferation, with an additive effect from combination therapy. Immunoblot analyses of MKN-45 and KATO-III cells revealed that dovitinib decreased phospho-FGFR, phospho-AKT, phospho-ERK, phospho-p70S6K, phospho-4EBP1, Bcl-2 and increased cleaved PARP-1, cleaved-caspase-3, p27, Bax, Bim, with an additive effect from combination therapy. These results demonstrate that the FGFR/VEGFR/PDGFR inhibitor, dovitinib, has the potential to augment the antitumor effects of nab-paclitaxel, with implications for use in the advancement of clinical GAC therapy.

A case from the future of HPB surgical oncology: resection of biliary tract cancer after immunotherapy

Biliary tract cancers (BTCs) have limited response to systemic therapy and poor prognosis. Immunotherapy in BTCs has been investigated in recent years. Here, we report a case of locally advanced, unresectable gallbladder adenocarcinoma that progressed on chemotherapy. The patient was then treated with ipilimumab and nivolumab, which resulted in tumor shrinkage and autoimmune hepatitis, but established technical resectability. He underwent complete resection through extended right hepatectomy with en bloc cholecystectomy bile duct resection, hepatic and portal lymphadenectomy and Roux-Y hepaticojejunostomy reconstruction. The final pathology revealed a pathologic complete response. The scope of operative intervention after immunotherapy is still evolving for BTCs. Establishing resectability in tumors not susceptible to cytotoxic agents but responding to immunotherapy not only facilitates curative intent resection but also enhances the importance of infection prevention through operative stent-free long-term biliary decompression. Immunotherapy may also carry a unique risk profile for post-operative morbidity potential as in this case with autoimmune hepatitis.

Abstract 1043: Enhancing cytotoxic chemotherapy effects by nintedanib in gastric cancer preclinical models

Background: Gastric adenocarcinoma (GAC) remains the 3rd most common cause of cancer mortality in the world. Systemic chemotherapy is a preferred treatment option for advanced and recurrent GAC, but response rates and survival extension remain limited. Tumor angiogenesis plays a critical role in GAC growth, invasion and metastasis. In this study, we determined the antitumor efficacy of nintedanib, a potent triple angiokinase inhibitor for VEGFR-1/2/3, PDGFR-α/β and FGFR-1/2/3, alone or in combination with chemotherapy, in preclinical models of GAC.

Methods: Animal survival and tumor growth studies were performed in 4-6 week-old female NOD/SCID mice with human GAC cell xenografts (MKN-45, KATO-III, SNU-5). The mechanistic evaluation involved Immunohistochemistry and Immunoblot analyses of subcutaneous tumors. In vitro cell viability assays were performed using colorimetric WST-1 reagent.

Results: In MKN-45 cell-derived peritoneal dissemination xenografts, animal survival was improved by nintedanib (33%), docetaxel (100%) or irinotecan (181%), while oxaliplatin, 5-FU and epirubicin had no effect. The addition of nintedanib to docetaxel (157%) or irinotecan (214%) led to a further extension in animal survival. In KATO-III cell-derived xenografts carrying FGFR2 gene amplification, nintedanib monotherapy extended survival much more (209%). Docetaxel and irinotecan effects were again further enhanced by nintedanib. In MKN-45 subcutaneous xenografts, nintedanib, epirubicin, docetaxel or irinotecan reduced tumor growth (range: 68-87%), while 5-FU and oxaliplatin had a smaller effect (40%). The addition of nintedanib to all chemotherapy groups demonstrated a further reduction in tumor growth. Subcutaneous tumor analysis revealed that nintedanib attenuated tumor cell proliferation, reduced tumor vasculature and increased tumor cell death. Nintedanib (10 μM) inhibited in vitro cell proliferation of mutationally different GAC cells by 25% (MKN-45), 75% (KATO-III) or 82% (SNU-5), and confirmed additive inhibitory effects in combinations with chemotherapy agents.

Conclusion: Nintedanib showed notable antitumor efficacy and significantly improved taxane or irinotecan chemotherapy responses. Combination regimens with nintedanib have the potential for improving clinical GAC therapy.

Citation Format: Niranjan Awasthi, Margaret A. Schwarz, Frank Hilberg, Roderich E. Schwarz. Enhancing cytotoxic chemotherapy effects by nintedanib in gastric cancer preclinical models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1043.

Targeted dual inhibition of c-Met/VEGFR2 signalling by foretinib improves antitumour effects of nanoparticle paclitaxel in gastric cancer models

Elevated expression of multiple growth factors and receptors including c‐Met and VEGFR has been reported in gastric adenocarcinoma (GAC) and thus provides a potentially useful therapeutic target. The therapeutic efficacy of foretinib, a c‐Met/VEGFR2 inhibitor, was determined in combination with nanoparticle paclitaxel (NPT) in GAC. Animal studies were conducted in NOD/SCID mice in subcutaneous and peritoneal dissemination xenografts. The mechanism of action was assessed by Immunohistochemical and Immunoblot analyses. In c‐Met overexpressing MKN‐45 cell‐derived xenografts, NPT and foretinib demonstrated inhibition in tumour growth, while NPT plus foretinib showed additive effects. In c‐Met low‐expressing SNU‐1 or patient‐derived xenografts, the foretinib effect was smaller, while NPT had a similar effect compared with MKN‐45, as NPT plus foretinib still exhibited an additive response. Median mice survival was markedly improved by NPT (83%), foretinib (100%) and NPT plus foretinib (230%) in peritoneal dissemination xenografts. Subcutaneous tumour analyses exhibited that foretinib increased cancer cell death and decreased cancer cell proliferation and tumour vasculature. NPT and foretinib suppressed the proliferation of GAC cells in vitro and had additive effects in combination. Further, foretinib caused a dramatic decrease in phosphorylated forms of c‐Met, ERK, AKT and p38. Foretinib led to a decrease in Bcl‐2, and an increase in p27, Bax, Bim, cleaved PARP‐1 and cleaved caspase‐3. Thus, these findings highlight the antitumour impact of simultaneous suppression of c‐Met and VEGFR2 signalling in GAC and its potential to enhance nanoparticle paclitaxel response. This therapeutic approach might lead to a clinically beneficial combination to increase GAC patients’ survival.

Telotristat ethyl to enhance cytotoxic chemotherapy response in preclinical cholangiocarcinoma models

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Background: Cholangiocarcinoma (CCA) is the second-most common primary liver cancer after hepatocellular carcinoma. It has a poor prognosis with a 5-year survival rate of 5-15%. The current standard first-line therapy for advanced unresectable CCA is a combination of gemcitabine and cisplatin (GemCis) chemotherapy that leads to a median survival of 6-12 months. Nanoparticle albumin-bound paclitaxel ( nab-paclitaxel, NPT) is an approved therapy for breast, NSCLC and pancreatic cancer. Elevated levels of serotonin have been reported in CCA that has protumorigenic activity. We tested the hypothesis that telotristat ethyl (TE), an inhibitor of serotonin biosynthesis, has antitumor activity in CCA and it augments GemCis and nab-paclitaxel response in preclinical CCA models. Methods: Tumor growth experiments were performed in mice subcutaneous CCA intrahepatic CCLP-1 xenografts, extrahepatic TFK-1 xenografts and patient-derived xenografts. Animal survival studies were performed using human CCA intrahepatic CCLP-1 cells in the peritoneal dissemination model in NOD/SCID mice. Results: In intrahepatic CCLP-1 subcutaneous xenografts, compared with controls, reduction in tumor growth was observed by TE (53%), GemCis (53%) or NPT (69%). The combination of TE with GemCis or NPT exhibited an additive tumor growth inhibition response, GemCis+TE (85%) and NPT+TE (90%). In extrahepatic TFK-1 subcutaneous xenografts, TE led to a significant reduction in tumor growth (51%), while GemCis and NPT reduced tumor growth by 37% and 56%, respectively. Again, an additive tumor growth inhibition effect was observed by the addition of TE to chemotherapy, GemCis+TE (67%) and NPT+TE (74%). In CCA patient-derived subcutaneous xenografts, GemCis caused the greatest tumor growth reduction (80%) followed by NPT (57%) and TE (40%). Combinations increased tumor inhibition further: GemCis+TE (95%) and NPT+TE (91%). Mouse survival in peritoneal dissemination xenografts was only marginally enhanced by TE (11%) or GemCis (9%) while NPT led to a substantial extension (60%). Interestingly, the combination of TE with GemCis or NPT demonstrated a further extension in mice survival: GemCis+TE (26%) and NPT+TE (68%). Conclusions: TE had antitumor activity and it enhanced chemotherapy effects in several CCA preclinical models indicating that this therapeutic combination has the potential to ameliorate clinical therapy for CCAs of different origin.

Abstract 553: Antitumor efficacy of a liposomal formulation of irinotecan in preclinical gastric cancer models: Augmenting its response by antiangiogenic agents

BACKGROUND: Gastric adenocarcinoma (GAC) remains the 3rd most common cause of cancer-related deaths worldwide. Systemic chemotherapy is commonly a fundamental treatment for metastatic GAC that usually leads to a modest patient benefit, resulting in a 5-year survival rate of 31%. A liposomal formulation of irinotecan (nal-IRI) has shown improved pharmacokinetic and drug biodistribution compared with free irinotecan (IRI) in preclinical studies. Angiogenesis plays a crucial role in the progression and metastasis of GAC. We evaluated the therapeutic efficacy of nal-IRI in combination with nintedanib, a tyrosine kinase inhibitor targeting FGFR, PDGFR and VEGFR, and DC101, a monoclonal antibody targeting VEGFR2 in preclinical models of GAC.

METHODS: In vitro cell proliferation was evaluated in three GAC cell lines (MKN-45, KATO-III and SNU-5) by WST-1 assay. Protein expression was measured by Western blot analysis in MKN-45 cell lysates. Animal survival studies were performed using two cell lines MKN-45 and KATO-III cells in peritoneal dissemination models in NOD/SCID mice (n=5-7). Tumor growth and pharmacokinetic studies were performed in GAC cell-derived xenografts. Mechanistic evaluation included IHC and Immunoblot analysis in tumor tissues.

RESULTS: Animal survival was increased by nal-IRI (&gt;156%) and IRI (&gt;94%) therapy compared with PBS-treated controls. Importantly, nal-IRI led to a &gt;30% extension of animal survival compared with IRI. The addition of antiangiogenic agents nintedanib or DC101 led to a further improvement (range 3-40%) in animal survival caused by nal-IRI and IRI. In GAC cell-derived subcutaneous xenografts, compared to controls, nal-IRI demonstrated greater tumor growth inhibition (92%) than IRI (71%). Here, the combinations of nal-IRI or IRI with antiangiogenic agents exhibited an additive response. Ki67 staining of tumor sections revealed that nal-IRI was most effective in reducing intratumoral proliferation (by 58%), followed by IRI (39%), nintedanib (33%), and DC101 (25%). Combinations of nal-IRI or IRI with antiangiogenic agents demonstrated an additive effect in reducing tumor cell proliferation. As expected, tumor vasculature (assessed by endomucin staining) was reduced by nintedanib (65%) and DC101 (58%), while nal-IRI and IRI showed no effect. Pharmacokinetic studies revealed that nal-IRI increased the retention, circulation time and tumor levels of IRI and its active metabolite SN-38. The addition of nintedanib or DC101 had no effect on plasma or tumor levels of IRI or SN38. In in vitro cell viability assays in mutationally different GAC cells, SN-38 had a dose-dependent growth inhibitory effect that was more pronounced than single-agent IRI. Importantly, combinations of SN-38 or IRI with antiangiogenic agents demonstrated additive effects on cell proliferation inhibition.

CONCLUSION: nal-IRI showed greater antitumor efficacy than IRI, and its antitumor effects can be enhanced by antiangiogenic agents suggesting that this combination has potential for improving clinical GAC therapy.

Citation Format: Niranjan Awasthi, Margaret A. Schwarz, Changhua Zhang, Stephan Klinz, Florence Meyer-Losic, Benjamin Beaufils, Arunthathi Thiagalingam, Roderich E. Schwarz. Antitumor efficacy of a liposomal formulation of irinotecan in preclinical gastric cancer models: Augmenting its response by antiangiogenic agents [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 553.

Combination effect of lapatinib with foretinib in HER2 and MET co-activated experimental esophageal adenocarcinoma

Recent studies have demonstrated that HER2 and MET receptor tyrosine kinases are co-overexpressed in a subset esophageal adenocarcinoma (EAC). We therefore studied the usefulness of combining HER2 and MET targeting by small-molecule inhibitors lapatinib and foretinib, respectively, both in in-vitro and in-vivo models of experimental EAC. We characterized MET and HER2 activation in a panel of human EAC cell lines, and the differential susceptibility of these EAC cell lines to single agent or combination of foretinib and lapatinib. We then explored the antitumor efficacy with survival advantage following foretinib and lapatinib monotherapy and in combination in murine subcutaneous xenograft and peritoneal metastatic survival models of human EAC. The OE33 EAC cell line with strong expression of phosphorylated both MET and HER2, demonstrated reduced sensitivity to foretinib and lapatinib when used as a single agent. The co-administration of foretinib and lapatinib effectively inhibited both MET and HER2 phosphorylation, enhanced inhibition of cell proliferation and xenograft tumor growth by inducing apoptosis, and significantly enhanced mouse overall survival, overcoming single agent resistance. In the OE19 EAC cell line with mainly HER2 phosphorylation, and the ESO51 EAC cell line with mainly MET phosphorylation, profound cell growth inhibition with induction of apoptosis was observed in response to single agent with lack of enhanced growth inhibition when the two agents were combined. These data suggest that combination therapy with foretinib and lapatinib should be tested as a treatment option for HER2 positive patients with MET-overexpressing EAC, and could be a novel treatment strategy for specific EAC patients.

Abstract 293: Inhibition of BET proteins augments nab-paclitaxel-gemcitabine-based chemotherapy response in preclinical models of pancreatic cancer

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) often presents with metastatic activity, leading to an extremely poor prognosis. Nanoparticle albumin-bound paclitaxel (NPT) in combination with gemcitabine (NPT+GEM) is a standard treatment for PDAC patients, resulting in a survival of ~8.5 months. Bromodomain and extraterminal domain (BET) proteins are epigenetic regulators of gene expression and are involved in cancer pathogenesis. Targeted inhibition of BET protein is currently under investigation for several cancers. We hypothesize that BET protein pathway inhibition by iBet-762 will enhance nab-paclitaxel-gemcitabine-based standard chemotherapy response in PDAC.

METHODS: In vitro cell proliferation assays were performed using WST-1 reagent. Protein expressions were determined by Western Blot analysis. In vivo animal survival and tumor growth experiments were performed in NOD-SCID mice.

RESULTS: BET inhibitor (iBET-762) and standard chemotherapy (NPT+Gem) had a dose-dependent in vitro growth inhibitory effect on several PDAC cell lines tested. Inhibition in cell proliferation at 1 μM drug concentration in NPT+Gem, iBET-762 and NPT+Gem+iBet-762 treatment groups was 64%, 27%, 76% in AsPC-1; 43%, 13%, 69% in Panc-1; and 42%, 51%, 75% in MIA PaCa-2 cells. Immunoblot analysis demonstrated that iBET-762 decreased the expression of oncogenic proteins c-Myc, β-catenin, vimentin and phospho-AKT, while increasing the expression of apoptosis-related proteins such as cleaved PARP-1 and cleaved caspase-3 and cell cycle inhibitor proteins P21 and P27. In subcutaneous xenografts, compared to controls, NPT+Gem and iBet-762 decreased tumor growth by 72% and 57%, respectively (p&lt;0.02). Importantly, the combination therapy group (NPT+Gem+iBet-762) had an additive effect on tumor growth inhibition (98%, p&lt;0.0001). In a peritoneal dissemination model, median animal survival compared to controls (21 days) was increased by NPT+Gem (33 days, a 57% increase) and iBet-762 (30 days, a 43% increase) therapy. This was further increased in the combination therapy group NPT+Gem+iBET-762 (44 days, a 110% increase).

CONCLUSION: These findings demonstrate that nab-paclitaxel-gemcitabine-based standard chemotherapy response can be enhanced through specific inhibition of BET proteins by iBET-762 in preclinical models of PDAC. The data support the potential of this combinatorial therapeutic strategy for clinical PDAC therapy.

Citation Format: Niranjan Awasthi, Sandeep Singh, Ross D. McCauley, Johann RE Schwarz, Margaret A. Schwarz, Roderich E. Schwarz. Inhibition of BET proteins augments nab-paclitaxel-gemcitabine-based chemotherapy response in preclinical models of pancreatic cancer [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 293.

Abstract 2208: Targeted inhibition of FGF/PDGF/VEGF signaling enhances nanoparticle taxane response in preclinical gastric cancer models

Background: Gastric adenocarcinoma (GAC) remains the third most common cause of cancer-related deaths worldwide. Most available systemic chemotherapy options for advanced GAC have limited efficacy. Nab-paclitaxel (NPT), a nanoparticle albumin-bound taxane formulation, has shown significant activity in preclinical GAC studies. Overexpression of multiple growth factors and their receptors such as FGF/FGFR, PDGF/PDGFR and VEGF/VEGFR, promote angiogenesis in several cancers including GAC that leads to tumor progression and metastasis. Dovitinib is a small molecule RTK inhibitor that potentially inhibits the activity of FGFR, PDGFR and VEGFR. We evaluated the antitumor efficacy of dovitinib and its ability to enhance nab-paclitaxel response in preclinical GAC models.

Methods: In vitro cell proliferation and protein expression were measured by WST-1 assay and Immunoblotting. In vivo tumor growth and animal survival studies were performed in NOD/SCID mice using human GAC MKN-45 cells.

Results: Nab-paclitaxel and dovitinib had in vitro growth inhibitory effect on several GAC associated cell lines tested, with additive effects in combination. Immunoblot analysis revealed that dovitinib treatment caused a decrease in the expression of phospho-FGFR, phospho-AKT, phospho-ERK; and an increase in the expression of apoptosis-related proteins cleaved PARP-1 and cleaved caspase-3. Nab-paclitaxel activity correlated with the increased expression of phospho-stathmin. In subcutaneous GAC xenografts, NPT and dovitinib demonstrated inhibition in tumor growth, while NPT+dovitinib had an additive effect. Net tumor growth was 533.7 mm3 in controls, 394.8 mm3 after oxaliplatin, 135.8 mm3 after NPT, 128 mm3 after dovitinib, 98.9 mm3 after oxaliplatin+dovitinib and -41.8 mm3 (tumor regression) after NPT+dovitinib. Tumor tissue analysis revealed that dovitinib reduced tumor vasculature, while nab-paclitaxel reduced tumor cell proliferation. In a peritoneal dissemination model, animal survival compared to controls (23 days) remained unchanged after monotherapy with oxaliplatin (24 days) or dovitinib (25 days) but increased significantly after NPT monotherapy (42 days, a 83% increase). Combination of dovitinib with NPT exhibited a further increase in animal survival (66 days, a 187% increase), while the combination of dovitinib with oxaliplatin had no survival benefit (25 days).

Conclusion: These findings demonstrate that the antitumor effect of nab-paclitaxel can be significantly enhanced by the FGFR/PDGFR/VEGFR pathway inhibitor dovitinib in preclinical GAC models. The data support the clinical relevance of this therapeutic combination for advanced GAC patients.

Citation Format: Niranjan Awasthi, Kate Crawford, Erin Bontrager, Sazzad Hassan, Urs von Holzen, Margaret A. Schwarz, Roderich E. Schwarz. Targeted inhibition of FGF/PDGF/VEGF signaling enhances nanoparticle taxane response in preclinical gastric cancer models [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 2208.

Therapeutic efficacy of anti-MMP9 antibody in combination with nab-paclitaxel-based chemotherapy in pre-clinical models of pancreatic cancer

Matrix metalloproteinase 9 (MMP9) is involved in the proteolysis of extracellular proteins and plays a critical role in pancreatic ductal adenocarcinoma (PDAC) progression, invasion and metastasis. The therapeutic potential of an anti‐MMP9 antibody (αMMP9) was evaluated in combination with nab‐paclitaxel (NPT)‐based standard cytotoxic therapy in pre‐clinical models of PDAC. Tumour progression and survival studies were performed in NOD/SCID mice. The mechanistic evaluation involved RNA‐Seq, Luminex, IHC and Immunoblot analyses of tumour samples. Median animal survival compared to controls was significantly increased after 2‐week therapy with NPT (59%), Gem (29%) and NPT+Gem (76%). Addition of αMMP9 antibody exhibited further extension in survival: NPT+αMMP9 (76%), Gem+αMMP9 (47%) and NPT+Gem+αMMP9 (94%). Six‐week maintenance therapy revealed that median animal survival was significantly increased after NPT+Gem (186%) and further improved by the addition of αMMP9 antibody (218%). Qualitative assessment of mice exhibited that αMMP9 therapy led to a reduction in jaundice, bloody ascites and metastatic burden. Anti‐MMP9 antibody increased the levels of tumour‐associated IL‐28 (1.5‐fold) and decreased stromal markers (collagen I, αSMA) and the EMT marker vimentin. Subcutaneous tumours revealed low but detectable levels of MMP9 in all therapy groups but no difference in MMP9 expression. Anti‐MMP9 antibody monotherapy resulted in more gene expression changes in the mouse stroma compared to the human tumour compartment. These findings suggest that anti‐MMP9 antibody can exert specific stroma‐directed effects that could be exploited in combination with currently used cytotoxics to improve clinical PDAC therapy.

Simplicity and Safety: Minimized Pancreatic Fistula Rate after Distal Pancreatectomy through Pancreas Stump Sutured Fish-Mouth Closure

Pancreatic stump leak after distal pancreatectomy (DP) is a major determinant for impaired postoperative recovery. Factors influencing pancreatic fistula (PF) occurrence remain of interest. Prospectively collected data from an academic surgical oncology practice were examined for predictors of PF. Seventy-five of 294 pancreatectomy patients underwent DP (26%). There were 33 men and 42 women, with a median age of 61 years (range: 18–85 years). Underlying conditions included cancer (60%) and benign processes (40%). Resections were comprising open DP (64%), laparoscopic DP (21%), and open multivisceral resections (15%). Of 21 cases with postoperative complications (28%, no death), six were PFs (8%, 2 grade A and 4 grade B). The median length of stay was six days (4–24). The PF rate was 2.0 per cent in 50 patients after sutured fish-mouth closures, but 20 per cent in cases using other techniques including stapling ( P = 0.007); no other variable was linked to PF occurrence. Length of stay was linked to complications, resection extent, malignancy, and transfusions (all at P < 0.02), but not to PF. PF rate after DP in this experience is unaffected by splenic vessel resection but seems to be minimized through a sutured fish-mouth closure technique.

Simplicity and Safety: Minimized Pancreatic Fistula Rate after Distal Pancreatectomy through Pancreas Stump Sutured Fish-Mouth Closure

Pancreatic stump leak after distal pancreatectomy (DP) is a major determinant for impaired postoperative recovery. Factors influencing pancreatic fistula (PF) occurrence remain of interest. Prospectively collected data from an academic surgical oncology practice were examined for predictors of PF. Seventy-five of 294 pancreatectomy patients underwent DP (26%). There were 33 men and 42 women, with a median age of 61 years (range: 18-85 years). Underlying conditions included cancer (60%) and benign processes (40%). Resections were comprising open DP (64%), laparoscopic DP (21%), and open multivisceral resections (15%). Of 21 cases with postoperative complications (28%, no death), six were PFs (8%, 2 grade A and 4 grade B). The median length of stay was six days (4-24). The PF rate was 2.0 per cent in 50 patients after sutured fish-mouth closures, but 20 per cent in cases using other techniques including stapling (P = 0.007); no other variable was linked to PF occurrence. Length of stay was linked to complications, resection extent, malignancy, and transfusions (all at P < 0.02), but not to PF. PF rate after DP in this experience is unaffected by splenic vessel resection but seems to be minimized through a sutured fish-mouth closure technique.

Pancreatic ductal adenocarcinoma cell secreted extracellular vesicles containing ceramide-1-phosphate promote pancreatic cancer stem cell motility

The high mortality rate associated with pancreatic ductal adenocarcinoma (PDAC) is in part due to lack of effective therapy for this highly chemoresistant tumor. Cancer stem cells, a subset of cancer cells responsible for tumor initiation and metastasis, are not targeted by conventional cytotoxic agents, which renders the identification of factors that facilitate cancer stem cell activation useful in defining targetable mechanisms. We determined that bioactive sphingolipid induced migration of pancreatic cancer stem cells (PCSC) and signaling was specific to ceramide-1-phosphate (C1P). Furthermore, PDAC cells were identified as a rich source of C1P. Importantly, PDAC cells express the C1P converting enzyme ceramide kinase (CerK), secrete C1P-containing extracellular vesicles that mediate PCSC migration, and when co-injected with PCSC reduce animal survival in a PDAC peritoneal dissemination model. Our findings suggest that PDAC secrete C1P-containing extracellular vesicles as a means of recruiting PCSC to sustain tumor growth therefore making C1P release a mechanism that could facilitate tumor progression.

Augmentation of Nab-Paclitaxel Chemotherapy Response by Mechanistically Diverse Antiangiogenic Agents in Preclinical Gastric Cancer Models

Gastric adenocarcinoma (GAC) remains the third most common cause of cancer-related deaths worldwide. Systemic chemotherapy is commonly recommended as a fundamental treatment for metastatic GAC; however, standard treatment has not been established yet. Angiogenesis plays a crucial role in the progression and metastasis of GAC. We evaluated therapeutic benefits of mechanistically diverse antiangiogenic agents in combination with nab-paclitaxel, a next-generation taxane, in preclinical models of GAC. Murine survival studies were performed in peritoneal dissemination models, whereas tumor growth studies were performed in subcutaneous GAC cell-derived or patient-derived xenografts. The mechanistic evaluation involved IHC and Immunoblot analysis in tumor samples. Nab-paclitaxel increased animal survival that was further improved by the addition of antiangiogenic agents ramucirumab (or its murine version DC101), cabozantinib and nintedanib. Nab-paclitaxel combination with nintedanib was most effective in improving animal survival, always greater than 300% over control. In cell-derived subcutaneous xenografts, nab-paclitaxel reduced tumor growth while all three antiangiogenic agents enhanced this effect, with nintedanib demonstrating the greatest inhibition. Furthermore, in GAC patient-derived xenografts the combination of nab-paclitaxel and nintedanib reduced tumor growth over single agents alone. Tumor tissue analysis revealed that ramucirumab and cabozantinib only reduced tumor vasculature, whereas nintedanib in addition significantly reduced tumor cell proliferation and increased apoptosis. Effects of nab-paclitaxel, a promising chemotherapeutic agent for GAC, can be enhanced by new-generation antiangiogenic agents, especially nintedanib. The data suggest that nab-paclitaxel combinations with multitargeted antiangiogenic agents carry promising potential for improving clinical GAC therapy. Mol Cancer Ther; 17(11); 2353-64. ©2018 AACR.

Physician derived versus administrative data in identifying surgical complications. Fact versus Fiction

BACKGROUND

Administrative data are widely used as determinants of surgical quality. We compared surgical complications identified in a structured surgical review to coding and billing data of over a 19-month period.

METHODS

A retrospective review of monthly morbidity and mortality conference reports was compared to a report over the same time period generated from hospital coding and billing data.

RESULTS

807 sequential operative procedures were included. Physician derived data compared to administrative data identified a complication of any severity in 205 (25.4%) versus 111 (13.8%) cases (r = 0.39), and major complications in 68 (8.4%) versus 46 (5.7%) cases (r = 0.36). Review of the administrative data regarding major complications identified 80 false negatives, 52 false positives, and 38 true positive designations. Overall sensitivity, specificity, positive and negative predictive values, and accuracy for administrative data in identifying major complications was 0.32, 0.99, 0.42, 0.99, and 0.99.

CONCLUSIONS

The correlation between physician determined and administrative data with regard to identifying surgical complications is poor. Administrative data are insensitive and lack positive predictive value.

Experience with a simplified feeding jejunostomy technique for enteral nutrition following major visceral operations

Background

Background: Perioperative nutrition support has been shown to impact on outcomes for patients with gastrointestinal cancer. Postoperative benefits of feeding tubes must be weighed against morbidity related to placement and use. A simplified jejunostomy tube technique was evaluated for outcomes.

Methods

A 16-Fr rubber tube is secured at the jejunal entry site without Witzel tunnel, followed by a continuous, circumferential and alternating suture between jejunal wall and parietal peritoneum. Prospectively collected data were analyzed.

Results

The technique was performed in 343 of 803 major hepatopancreatobiliary and upper gastrointestinal (GI) resections (43%). Of these patients (male =57%, median age: 65.8 years, range, 24.0-98.0 years), 89% had a cancer diagnosis. The procedures included pancreatectomy (n=189, 55%), gastrectomy (n=109, 32%), esophagectomy (n=19, 6%) and others (n=26, 7%). The operative intent was curative in 78%, palliative in 10%, or combined in 12% of patients. Postoperative morbidity rate was 40%, with 19 lethal events (5.5%), and a median length of stay of 10 days (range, 4-111 days). Tube feeds were administered in 139 patients (41%), and in 17% continued beyond discharge. Use of the feeding tube was linked to treatment interval, length of stay, major complication grade (all at P<0.0001), metastatic stage (P=0.0007) and noncurative intent (P=0.001). Tube feeds beyond discharge were associated with time interval (P<0.0001), length of stay (P=0.0006) and noncurative intent (P=0.014). Tube-specific events in 38 patients (11%) were all minor, without any intraabdominal leak, infection or obstruction.

Conclusions

The technique described is safe and expedient, and the overall tube-related morbidity is low. This procedure can be recommended in cases at risk for major morbidity and nutrition support needs.

Clinical trends and effects on quality metrics for surgical gastroesophageal cancer care

Background

Surgical therapy of mid-stage gastric cancer (GC) and other neoplastic conditions requiring gastric resection remains at the center of curative outcomes, while epidemiologic changes and multimodality treatment options have evolved rapidly. Putative quality metrics for gastrectomy such as R0 rate, total lymph node (LN) count or postoperative morbidity may depend partly on changing disease and treatment patterns, and deserve evaluation under various practice conditions.

Methods

Data within a U.S.-based single surgical oncologist's practice over 15 years were prospectively recorded and retrospectively analyzed for clinicopathologic factors, operative treatment aspects and outcomes. Trends and spectrum changes over three time intervals were analyzed with contingency analysis and continuous data comparative statistics.

Results

Of 179 patients undergoing gastric resection, 119 were male and 60 female, with a median age of 63 years (range, 24-98 years). Resections included 56 total, 56 subtotal/distal, 30 proximal and 37 segmental gastrectomies. Diagnoses included 96 GCs, 31 gastroesophageal (GE) junction (GEJ) cancers, 21 GI stromal tumors (GISTs), and 31 other conditions. Significant trends from first towards last time interval were observed for resection type (16% to 32% proximal, 9% to 30% segmental, P=0.0003), curative intent (76% to 98%, P=0.002), diagnosis (5% to 42% GEJ cancer, P<0.0001) and preoperative therapy use (0% to 58%, P<0.0001), among others. Intraoperative aspects showed significantly reduced blood loss (median: 500 to 150 mL) and transfusion requirements (39% to 4%), and an increased use of minimally invasive techniques over time (all at P<0.001). Among patients undergoing curative intent GC resection with LN dissection, total LN counts remained steady (mean: 26), while the number of involved LNs decreased (9.0 to 3.7, P=0.0003) and the R0 resection rate increased from 74% to 85% (P=0.05). The number of specimens with >15 LNs examined increased from 69.0% to 92.5% (P=0.022). At the same time, spleen preservation rate (91% overall) and major morbidity (16%) remained unchanged throughout. Postoperative length of stay decreased from a median of 12 to 8 days (P<0.0001).

Conclusions

This experience represents some variable practice patterns within a clinicopathologic spectrum of GE diseases. Postoperative or oncologic quality metrics have been sustained or did improve, which would support their utility for various practice settings; they compare favorably to other published U.S. experiences during the same time period.

Abstract 5807: The dual c-Met/VEGFR2 inhibitor foretinib augments chemotherapy response in preclinical models of gastric cancer

BACKGROUND: Gastric adenocarcinoma (GAC) is the fourth most common malignant tumor in the world. Several growth factors and their receptors including c-Met and VEGFR, are overexpressed in GAC and thus provide a potentially effective therapeutic target. Foretinib is a novel small molecule inhibitor of the c-Met and VEGFR pathways. We evaluated the therapeutic efficacy of foretinib to enhance the antitumor response of nab-paclitaxel (NPT), a water-soluble albumin-bound formulation of paclitaxel, or oxaliplatin in preclinical models of GAC.

METHODS: Tumor growth experiments were performed in subcutaneous xenografts in NOD/SCID mice using 5x106 MKN-45 cells. Animal survival study was performed as peritoneal dissemination model in NOD/SCID mice using 10x106 MKN-45 cells. The mechanistic evaluation involved immunohistochemical and Immunoblot analyses.

RESULTS: In subcutaneous GAC xenografts, NPT and foretinib monotherapies demonstrated inhibition in tumor growth, while NPT plus foretinib combined showed additive effects. Net tumor growth in different therapy groups was 581.7 mm3 in controls, 397.9 mm3 after oxaliplatin, 229.9 mm3 after NPT, -82.6 mm3 (tumor regression) after foretinib, -74.1 mm3 after oxaliplatin+foretinib and -96.3 mm3 after NPT+foretinib. No significant change in body weight was observed for those mice treated with nab-paclitaxel, oxaliplatin or foretinib. In the GAC survival model, median animal survival compared to controls (23 days) remained unchanged after oxaliplatin therapy (24 days, p=ns) but increased after monotherapy with NPT (42 days, an 83% increase, p=0.0014) or foretinib (46 days, a 100% increase, p=0.0006). Importantly, a further increase in animal survival was observed in combination therapy groups: oxaliplatin+foretinib (55 days, a 139% increase, p=0.0006) and NPT+foretinib (76 days, 230% increase, p=0.0006). Effects of therapy on intratumoral proliferation and microvessel density corresponded with tumor growth inhibition data. In vitro studies demonstrated inhibition in the proliferation of GAC cells by both NPT and foretinib, with additive effects in combination. Immunoblot analysis revealed that foretinib pre-exposure blocked HGF-induced expression of phospho-c-Met. Furthermore, the foretinib treatment caused a decrease in phosphorylation of AKT, ERK, and PLC-γ in GAC cells, either alone or in combination with nab-paclitaxel.

CONCLUSION: These findings suggest that the antitumor effect of chemotherapy can be significantly enhanced by the c-Met/VEGFR pathway inhibitor foretinib, which might lead to clinically relevant therapeutic combinations to increase survival of GAC patients.

Citation Format: Niranjan Awasthi, Meghan Grojean, Sheena Monahan, Sazzad Hassan, Urs von Holzen, Margaret A. Schwarz, Roderich E. Schwarz. The dual c-Met/VEGFR2 inhibitor foretinib augments chemotherapy response in preclinical models of gastric cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5807.

Abstract 4826: Synergistic effects of foretinib with lapatinib in MET and HER2 co-activated experimental esophageal adenocarcinoma

Introduction: Recent studies have demonstrated that HER2 and MET receptor tyrosine kinases are co-overexpressed in a subset esophageal adenocarcinoma (EAC). We therefore studied the usefulness of combining HER2 and MET targeting by small-molecule inhibitors foretinib and lapatinib both in-vitro and in-vivo models of experimental EAC.

Methods: In this study we first characterized MET and HER2 activation in a panel of human EAC cell lines and the differential susceptibility of these EAC cell lines to single agents or combinations of foretinib, a multi-kinase MET inhibitor, with HER2 targeted agent lapatinib. We evaluated the levels of phosphorylation status of MET and HER2 proteins using western blot in EAC cell lines. Foretinib and lapatinib, as single agent or in combination were tested for effect on cell growth as detected by WST-1 assay and on cell apoptosis as detected by western blot of cleavage of caspase 3 and poly ADP ribose polymerase (PARP). In addition, we explored the antitumor efficacy with survival advantage following foretinib and lapatinib mono and combination therapies for two weeks in murine subcutaneous xenograft and peritoneal metastatic survival models of human EAC.

Results: The OE33 EAC cell line with phosphorylation of both MET and HER2, demonstrated reduced sensitivity to foretinib and lapatinib when used as a single agent. The co-administration of foretinib and lapatinib effectively inhibited both MET and HER2 phosphorylation, synergistically inhibited cell growth and induced apoptosis, overcoming single agent resistance. In the OE19 EAC cell line with only HER2 phosphorylation and the ESO51 EAC cell line with only MET phosphorylation, profound cell growth inhibition with induction of apoptosis was observed in response to single agent foretinib and lapatinib, respectively, with lack of enhanced growth inhibition when the two drugs were combined. Foretinib in combination with lapatinib treatment resulted in significantly higher antitumor efficacy and survival benefit compared with foretinib or lapatinib treatment alone. In subcutaneous xenografts using OE33 cells, average net tumor growth after two weeks in different therapy groups was 247.83 mm3 in control, 216.71 mm3 after foretinib (p=0.49), 239.68 mm3 after lapatinib (p=0.74), and 108.06 mm3 after foretinib plus lapatinib (p=0.0011). In the OE33 survival model there was a significant increase in median animal survival after two weeks foretinib plus lapatinib treatment (71 days) compared to control (60 days, p=0.0021), to foretinib therapy (63 days, p=0.0019) or to lapatinib (61 days, p=0.0019) therapy.

Conclusion: These data suggest that combination therapy with foretinib and lapatinib should be tested as a treatment option for HER2 positive patients with MET-overexpressing EAC. Therefore, this combination therapy could be a novel treatment strategy for EAC with MET and HER co-activation.

Citation Format: Md Sazzad Hassan, Fiona Williams, Niranjan Awasthi, Margaret A. Schwarz, Roderich E. Schwarz, Urs von Holzen. Synergistic effects of foretinib with lapatinib in MET and HER2 co-activated experimental esophageal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4826.

Abstract 4813: Enhancement of nab-paclitaxel response by inhibition of insulin-like growth factor (IGF) signaling in experimental esophageal adenocarcinoma

Introduction: Esophageal adenocarcinoma (EAC) is the fastest growing cancer in the western world and the overall 5 year survival rate of EAC is below 20 percent. Most patients with EAC present with locally advanced or widespread metastatic disease, where current treatment is largely ineffective. Therefore, new therapeutic approaches are urgently needed. Epidemiological studies have linked obesity with EAC. IGF signaling is an important mediator in obesity-associated EAC. Paclitaxel (PT) has been used in combination with carboplatin as a standard combination therapy for advanced EAC. PT required emulsification with solvents which has resulted in serious adverse effects in patients. Nanoparticle albumin-bound paclitaxel (nab-paclitaxel) is an albumin-stabilized, cremophor-free and water soluble nanoparticle formulation of PT. Nab-paclitaxel has recently shown greater efficacy over PT in EAC. Here we evaluated the improvement in nab-paclitaxel response by addition of BMS-754807, a small molecule inhibitor of IGF-1R/IR signaling, in experimental EAC.

Methods: We first evaluated the phosphorylation status of IGF-1R/IR protein by western blot in a panel of EAC cell lines. BMS-754807 and nab-paclitaxel, alone or in combination were tested for effects on cell growth detected by WST-1 assay and on cell apoptosis detected by western blot of cleavage of caspase 3 and PARP. We then explored the antitumor efficacy with survival advantage following BMS-754807 and nab-paclitaxel mono and combination therapies in murine subcutaneous xenograft and peritoneal metastatic survival models of human EAC.

Results: BMS-754807 dose dependently inhibited in-vitro cell proliferation of OE19 and FLO-1 EAC cell lines having strong tyrosine phosphorylation of IGF-1R/IR protein and interestingly the addition of IC25 dose of BMS-754807 significantly decreased the nab-paclitaxel IC50 in these EAC cells. In addition, co-administration of BMS-754807 and nab-paclitaxel effectively enhanced cleavage of caspase-3 and PARP in these EAC cells. In subcutaneous xenografts using OE19 cells, average net tumor growth after two weeks in different therapy groups was 558.67 mm3 in control, 208.47 mm3 after BMS-754807 (p=0.043), 104.60 mm3 after nab-paclitaxel (p=0.013), and 14.30 mm3 after BMS-754807 plus nab-paclitaxel (p=0.0005). In OE19 EAC survival model there was a significant increase in median animal survival after two weeks BMS-754807 plus nab-paclitaxel treatment (85 days) compared to control (47 days, p=0.0034), to BMS-754807 therapy (57 days, p=0.0021) or to nab-paclitaxel (68 days, p=0.0339) therapy.

Conclusion: Thus BMS-754807 with nab-paclitaxel treatment resulted in significantly higher antitumor efficacy and survival benefit. These results support the potential of BMS-754807 in combination with nab-paclitaxel as an effective option for EAC therapy.

Citation Format: Md Sazzad Hassan, Fiona Williams, Niranjan Awasthi, Margaret A. Schwarz, Roderich E. Schwarz, Urs von Holzen. Enhancement of nab-paclitaxel response by inhibition of insulin-like growth factor (IGF) signaling in experimental esophageal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4813.

Abstract 4822: Anti-MMP9 antibody in combination with standard cytotoxic therapy in preclinical models of pancreatic cancer

BACKGROUND: Matrix metalloproteinase 9 (MMP9) is involved in the proteolysis of extracellular proteins and is reported to play a key role in development, invasion and metastasis of many cancers including pancreatic ductal adenocarcinoma (PDAC). Andecaliximab is a potent and highly selective monoclonal antibody inhibitor of MMP9 that has shown antitumor activity in combination with chemotherapy in gastric cancer. The therapeutic potential of targeted MMP9 inhibition in combination with cytotoxic therapy in preclinical models of PDAC was evaluated through the use of an αMMP9 antibody.

METHODS: Animal survival and qualitative analysis were performed in the peritoneal dissemination model in mice using 7.5x105 AsPC-1 cells. Tumor growth study was performed in subcutaneous xenografts in mice using 7.5x105 AsPC-1 cells. The mechanistic evaluation involved RNASeq, Luminex, IHC and Immunoblot analysis in tumor samples.

RESULTS: Median animal survival compared to controls (17 days) was increased after 2-week therapy with NPT (27 days, a 59% increase), Gem (22 days, +29%) and NPT+Gem (30 days, +76%). Addition of αMMP9 antibody increased survival as follows: NPT+MMP9 (30 days, +76%), Gem+MMP9 (25 days, +47%) and NPT+Gem+MMP9 (33 days, +94%). Evaluation of efficacy of maintenance therapy (6-weeks) revealed that median animal survival (controls: 22 days) was increased after NPT+Gem therapy (63 days, +186%) and further improved by addition of αMMP9 antibody (70 days, +218%). Qualitative assessment of mice after 2-week therapy revealed that αMMP9 therapy led to reduction in jaundice, bloody ascites and metastatic burden, both alone and in combination with NPT+Gem. Tumor lysates demonstrated changes in several proteins in chemotherapy groups including IP-10, MDC, PAI-1, GM-CSF, MIP-1b and IL-12b. αMMP9 therapy increased IL-28 (1.5 fold, p = 0.016). IHC analysis revealed decreased tumor microvessel density based on endomucin staining in αMMP9 therapy groups (59.9%, p&lt;0.0001). Immunoblot analysis showed decreased vimentin expression in αMMP9 therapy groups (42.5%, p =0.03). In tumor growth study, NPT+Gem significantly decreased tumor growth (72%, p=0.0005) compared to controls. αMMP9 therapy caused a non-significant decrease in tumor growth (17%, p=0.24). Tumor tissues revealed low, but detectable levels of MMP9 mRNA in all therapy groups but no difference in MMP9 expression. αMMP9 monotherapy resulted in more gene expression changes in the mouse stromal than the human tumor compartment compared to other treatments. However, NPT+Gem+MMP9 combination therapy resulted in greater numbers of changes in gene expression compared to the other treatments in the tumor compartment.

CONCLUSION: These findings suggest that MMP9 inhibition can augment the effects of standard cytotoxic therapy and support the potential of this combination therapeutic strategy for clinical PDAC therapy.

Citation Format: Niranjan Awasthi, Amanda Mikels-Vigdal, Erin Stefanutti, Margaret A. Schwarz, Sheena Monahan, Victoria Smith, Roderich E. Schwarz. Anti-MMP9 antibody in combination with standard cytotoxic therapy in preclinical models of pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4822.

Managing the Unmanageable: A Two-Staged Palliative Resection to Control Life-Threatening Duodenal Bleeding Due to Recurrent Paraganglioma

Patient: Male, 40

Final Diagnosis: Paraganglioma

Symptoms: GI bleeding • syncope

Medication: —

Clinical Procedure: Palliative multivisceral staged resection

Specialty: Surgery

Abstract LB-B29: Combined inhibition of MAPK and PI3K signaling augments standard chemotherapy response in preclinical models of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) remains a highly lethal cancer with mortality closely paralleling incidence despite substantial advances in biological understanding of the disease. Nab-paclitaxel (NPT) plus Gemcitabine (Gem) represents the current standard for systemic therapy of advanced PDAC. More than 90% of PDACs harbor an activating mutation in the KRAS oncogene. Presently, no therapeutics exist that effectively target this oncogene, but alternative strategies focus on inhibition of downstream effectors of KRAS signaling pathways. The RAF-MEK-ERK (MAPK) and the AKT-PI3K signaling pathways are well-described mediators of KRAS induced transformation and tumorigenesis in several cancers including PDAC and represent potential targets for combination therapy. We evaluated combination treatment benefits of NPT+Gem with the MEK inhibitor trametinib (Tra) and the AKT inhibitor MK-2206 (MK) in preclinical models to evaluate their therapeutic potential against PDAC.

An animal survival study was performed in peritoneal dissemination model in NOD/SCID mice. Tumor growth inhibition studies were performed in subcutaneous PDAC cell-line-derived xenografts and PDAC patient-derived xenografts in mice. Intratumoral mechanism of action was determined by immunohistochemistry (IHC) and Immunoblot analysis.

Median animal survival in peritoneal dissemination PDAC xenografts in mice revealed that the median survival was 21 days in controls, which was significantly improved by the NPT+Gem combination (35 days, a 67% increase over controls). Median survival was further increased by addition of trametinib or MK-2206 to the NPT+Gem chemotherapy regimen: NPT+Gem+Tra (43 days, a 105% increase over controls), NPT+Gem+MK (39 days, a 86% increase over controls) and NPT+Gem+MK+Tra (48 days, a 129% increase over controls). In human subcutaneous xenografts using AsPC-1 PDAC cells, trametinib and MK-2206 were also able to enhance NPT+Gem effects. Compared to controls (100±34.8), the percent net local tumor growth in different therapy groups was 21.8±5.9 for NPT+Gem, 7.1±11.2 for NPT+Gem+Tra, 17.2±4.8 for NPT+Gem+MK and 5.7±9.1 for NPT+Gem+MK+Tra. Effects of therapy on intratumoral proliferation and apoptosis corresponded with tumor growth inhibition data. Furthermore, in vivo effects of trametinib and MK-2206 correlated with reduced expression of phospho-ERK and phospho-AKT in tumor samples. More importantly, in a recently completed patient-derived xenograft study, we observed that the addition of trametinib or MK-2206 again augmented the NPT+Gem tumor growth inhibition response. In this experiment, compared to controls (350 mm3), the net local tumor growth in different therapy groups was 145.4 mm3 for NPT+Gem, 122 mm3 for NPT+Gem+Tra, 20.4 mm3 for NPT+Gem+MK and -43.7 mm3 (tumor regression) for NPT+Gem+MK+Tra.

These findings from multiple preclinical model settings suggest that the effects of NPT+Gem can be enhanced through combined inhibition of MAPK and PI3K signaling, which supports the potential of these targets for clinical PDAC therapy.

Citation Format: Niranjan Awasthi, Sheena Monahan, Alexis Stefaniak, Margaret A. Schwarz, Roderich E. Schwarz. Combined inhibition of MAPK and PI3K signaling augments standard chemotherapy response in preclinical models of pancreatic cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr LB-B29.

Inhibition of the MEK/ERK pathway augments nab-paclitaxel-based chemotherapy effects in preclinical models of pancreatic cancer

Nab-paclitaxel (NPT) combination with gemcitabine (Gem) represents the standard chemotherapy for pancreatic ductal adenocarcinoma (PDAC). Genetic alterations of the RAS/RAF/MEK/ERK (MAPK) signaling pathway yielding constitutive activation of the ERK cascade have been implicated as drivers of PDAC. Inhibition of downstream targets in the RAS-MAPK cascade such as MEK remains a promising therapeutic strategy. The efficacy of trametinib (Tra), a small molecule inhibitor of MEK1/2 kinase activity, in combination with nab-paclitaxel-based chemotherapy was evaluated in preclinical models of PDAC. The addition of trametinib to chemotherapy regimens showed a trend for an additive effect on tumor growth inhibition in subcutaneous AsPC-1 and Panc-1 PDAC xenografts. In a peritoneal dissemination model, median animal survival compared to controls (20 days) was increased after therapy with NPT (33 days, a 65% increase), Tra (31 days, a 55% increase), NPT+Tra (37 days, a 85% increase), NPT+Gem (39 days, a 95% increase) and NPT+Gem+Tra (49 days, a 145% increase). Effects of therapy on intratumoral proliferation and apoptosis corresponded with tumor growth inhibition. Trametinib effects were specifically accompanied by a decrease in phospho-ERK and an increase in cleaved caspase-3 and cleaved PARP-1 proteins. These findings suggest that the effects of nab-paclitaxel-based chemotherapy can be enhanced through specific inhibition of MEK1/2 kinase activity, and supports the clinical application of trametinib in combination with standard nab-paclitaxel-based chemotherapy in PDAC patients.

Abstract 4202: Trametinib, a MEK inhibitor, augments nab-paclitaxel based chemotherapy response in preclinical models of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is currently the third leading cause of cancer related deaths in the USA with a 5-year survival less than 6%. Nanoparticle albumin-bound paclitaxel (nab-paclitaxel, NPT) has demonstrated 8.5 months median survival in combination with gemcitabine, and now represents a standard of care for PDAC patients. Genetic alterations of the RAS/RAF/MEK/ERK (MAPK) signaling pathway yielding constitutive activation of the ERK cascade have been implicated in many human cancers. In PDAC, activating K-ras mutations occur at a frequency of 90%, rendering this a potential therapeutic target. Efforts to develop drugs that directly target mutant KRAS protein remain challenging due to target specificity issues. Alternative strategies therefore focus towards inhibition of downstream targets in the RAS-MAPK cascade such as MEK. Trametinib (Tra) is a potent and highly selective small molecule inhibitor of MEK1/2 kinase activity. We evaluated efficacy of trametinib to enhance antitumor response of nab-paclitaxel based chemotherapy regimens in preclinical models of PDAC using K-ras mutant cell lines.

In subcutaneous PDAC xenografts using AsPC-1 cells, net tumor growth in different therapy groups was 432.6 mm3 in controls, 105.3 mm3 after NPT (p=0.0023), 184 mm3 after Tra (p=0.0018), 81 mm3 after NPT+Tra (p=0.0003), 37.3 mm3 after NPT+Gem (p=0.0025) and -8.1 mm3 (tumor regression) after NPT+Gem+Tra (p&lt;0.0001). In another subcutaneous PDAC xenografts using Panc-1 cells, net tumor growth in different therapy groups was: 274.1 mm3 in controls, 80.8 mm3 after NPT (p=0.0002), 150.6 mm3 after Tra (p=0.0047), 75.1 mm3 after NPT+Tra (p=0.0002), 48.4 mm3 after NPT+Gem (p=0.0004) and 3.8 mm3 after NPT+Gem+Tra (p&lt;0.0001). In PDAC peritoneal dissemination model using AsPC-1 cells, median animal survival compared to controls (20 days) was increased after therapy with NPT (33 days, a 65% increase, p=0.0004), Tra (31 days, a 55% increase, p=0.0004), NPT+Tra (37 days, a 85% increase, p=0.0001), NPT+Gem (39 days, a 95% increase, p=0.0001) and NPT+Gem+Tra (49 days, a 145% increase, p&lt;0.0001). Effects of therapy on intratumoral proliferation and apoptosis corresponded with tumor growth inhibition data. In vitro studies demonstrated inhibition in PDAC cell (AsPC-1, Panc-1, Mia PaCa-2, CFPAC) proliferation by NPT+Gem, Tra, and combination. Immunoblot analysis revealed that trametinib effects were specifically accompanied by decrease in phospho-ERK expression and increase in the expression of apoptosis-related cleaved caspase-3 and cleaved PARP-1 proteins. These findings suggest that the effects of nab-paclitaxel based chemotherapy regimens can be enhanced through specific inhibition of MEK1/2 kinase activity, which clinically could lead to improved PDAC therapy effects.

Citation Format: Niranjan Awasthi, Sheena Monahan, Alexis Stefaniak, Margaret A. Schwarz, Roderich E. Schwarz. Trametinib, a MEK inhibitor, augments nab-paclitaxel based chemotherapy response in preclinical models of pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4202. doi:10.1158/1538-7445.AM2017-4202

Abstract 2040: Superior therapeutic efficacy of nanoparticle albumin-bound paclitaxel over cremophor-bound paclitaxel in experimental esophageal adenocarcinoma

Introduction: Esophageal adenocarcinoma (EAC) has become the dominant type of esophageal cancer in United States. EAC is the fastest growing cancer in the western world and the overall 5 year survival rate of EAC is below 20 percent. Most patients with EAC present with locally advanced or widespread metastatic disease, where current treatment is largely ineffective. Prognosis for EAC patients remains poor even with combination therapies due to high resistance to chemotherapy. Therefore, new therapeutic approaches are urgently needed. Paclitaxel (PTX) has been used in combination with carboplatin (CP) as a standard combination therapy for advanced EAC. PTX required emulsification with solvents to allow intravenous administration which has resulted in hypersensitivity reactions and potentially dramatic side effects in patients. Nanoparticle albumin-bound (nab) PTX is an albumin-stabilized, cremophor-free and water soluble nanoparticle formulation of PTX. Nab-PTX is a novel microtubule-inhibitory cytotoxic agent and the potential role of nab-PTX has not been tested yet in experimental EAC.

Methods: We explored the antiproliferative and antitumor efficacy with survival advantage following CP, PTX and nab-PTX as monotherapy and in combinations in in-vitro, and in murine subcutaneous xenograft and peritoneal metastatic survival models of human EAC.

Results: Nab-PTX inhibited in-vitro cell proliferation with significantly lower IC50 (0.25 µM in OE19 and 49 nM in OE33) than that of PTX (0.74 µM in OE19 and 98 nM in OE33) and CP (5.21 µM in OE19 and 1.05 µM in OE33) in OE19 and OE33 EAC cell lines. Nab-PTX treatment resulted in significantly higher antitumour efficacy and survival benefit compared with PTX or CP treatment. After two-week nab-PTX, PTX, CP, nab-PTX+CP or PTX+CP treatments, the average in-vivo local tumor growth inhibition rate was 73, 60, 35, 81 and 68 percent respectively (p=0.025). Nab-PTX treatment increased expression of the mitotic-spindle associated phospho-stathmin, decreased expression of proliferative marker Ki-67 and enhanced apoptosis as confirmed by increased expression of cleaved-PARP and cleaved caspase-3. There was an increase in median animal survival after nab-PTX treatment (65 days) compared to controls (46 days, p=0.0023), PTX (57 days, p=0.0034) or to CP therapy (53 days, p=0.0034).

Conclusion: In conclusion, the present study demonstrates that nab-PTX had stronger antiproliferative and antitumor activity in experimental EAC than the current standard chemotherapeutic agents. This strong antitumor activity supports the rationale for clinical evaluation of nab-PTX as promising microtubule-inhibitory agent in EAC.

Citation Format: Md Sazzad Hassan, Niranjan Awasthi, Roderich E. Schwarz, Margaret A. Schwarz, Urs von Holzen. Superior therapeutic efficacy of nanoparticle albumin-bound paclitaxel over cremophor-bound paclitaxel in experimental esophageal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2040. doi:10.1158/1538-7445.AM2017-2040

Institutional variants for lymph node counts after pancreatic resections

BACKGROUND

Lymph node (LN) counts from pancreatectomy are postulated as quality metric for surgical therapy of pancreatic malignancy.

METHODS

Prospectively collected data from a single surgeon's pancreatectomy experience were analyzed for predictors of LN counts.

RESULTS

Of 315 consecutive patients (54% female, median age: 65, range 18-88), 239 had a proven cancer diagnosis (76%). Operations included pancreatoduodenectomy (69%), distal pancreatectomy (26%), total pancreatectomy (1%) and others (4%). Patients were treated in 4 different tertiary cancer center settings (Institution A: 11%; B: 46%; C: 27%; D: 16%) with consistent regional dissection standards. Mean total LN counts differed between institutions for malignancies (A: 18, B: 13, C: 26, D: 26, p < 0.0001) and benign diseases (p = 0.003). At least 15 LNs were reported in 63% of cancer patients (institution range: 34-92%, p < 0.0001).

CONCLUSIONS

Pathologic processing should be standardized if LN numbers are to be adopted as quality metric for pancreatic cancer resections.

A positive crosstalk between CXCR4 and CXCR2 promotes gastric cancer metastasis

The molecular mechanism underlying gastric cancer (GC) invasion and metastasis is still poorly understood. In this study, we tried to investigate the roles of CXCR4 and CXCR2 signalings in gastric cancer metastasis. A highly invasive gastric cancer cell model was established. Chemokines receptors were profiled to search for the accountable ones. Then the underlying molecular mechanism was investigated using both in vitro and in vivo techniques, and the clinical relevance of CXCR4 and CXCR2 expression was studied in gastric cancer samples. CXCR4 and CXCR2 were highly expressed in a high invasive gastric cancer cell model and in gastric cancer tissues. Overexpression of CXCR4 and CXCR2 was associated with more advanced tumor stage and poorer survival for GC patients. CXCR4 and CXCR2 expression strongly correlated with each other in the way that CXCR2 expression changed accordingly with the activity of CXCR4 signaling and CXCR4 expression also changed in agreement with CXCR2 activity. Further studies demonstrated CXCR4 and CXCR2 can both activated NF-κB and STAT3 signaling, while NF-κBp65 can then transcriptionally activate CXCR4 and STAT3 can activate CXCR2 expression. This crosstalk between CXCR4 and CXCR2 contributed to EMT, migration and invasion of gastric cancer. Finally, Co-inhibition of CXCR4 and CXCR2 is more effective in reducing gastric cancer metastasis. Our results demonstrated that CXCR4 and CXCR2 cross-activate each other to promote the metastasis of gastric cancer.

Vascular challenges from pancreatoduodenectomy in the setting of coeliac artery stenosis

Coeliac artery stenosis due to median arcuate ligament compression or atherosclerotic disease is a frequently unrecognised challenge to recovery after pancreatoduodenectomy. The described case illustrates management with intraoperative superior mesenteric artery to hepatic artery bypass graft that led to haemorrhagic challenges postoperatively but ultimately a good recovery. Aspects of preoperative diagnosis, preoperative intervention and intraoperative management options are reviewed. Surgeons need to possess these tools to prevent complications from coeliac artery stenosis when pancreatoduodenectomy is required.

The impact of immediate breast reconstruction after mastectomy on time to first adjuvant treatment in women with breast cancer in a community setting

BACKGROUND

The impact of immediate breast reconstruction on the time to first adjuvant therapy is controversial.

METHODS

Retrospective study design comparing time to first treatment in women undergoing mastectomy with and without immediate reconstruction in a community cancer center.

RESULTS

Seventy-six cases fit inclusion criteria of which 44 (58%) underwent mastectomy with immediate reconstruction. Women undergoing immediate reconstruction were younger, had more bilateral mastectomies and had fewer prior breast procedures. The median time to first adjuvant therapy was longer in the immediate reconstruction group [80.5days (36-343) versus 53.5 days (18-96), p = 0.003]. Fifteen of 44 patients had the start of adjuvant treatment over 90 days after resection, 14 of whom (93%) had immediate reconstruction versus 1 (7%) who did not (p = 0.01).

CONCLUSION

In this study immediate breast reconstruction was associated with a longer time to first adjuvant treatment, with adjuvant therapies being more likely delayed over 90 days.

Endothelial Monocyte-Activating Polypeptide II Mediates Macrophage Migration in the Development of Hyperoxia-Induced Lung Disease of Prematurity

Myeloid cells are key factors in the progression of bronchopulmonary dysplasia (BPD) pathogenesis. Endothelial monocyte-activating polypeptide II (EMAP II) mediates myeloid cell trafficking. The origin and physiological mechanism by which EMAP II affects pathogenesis in BPD is unknown. The objective was to determine the functional consequences of elevated EMAP II levels in the pathogenesis of murine BPD and to investigate EMAP II neutralization as a therapeutic strategy. Three neonatal mouse models were used: (1) BPD (hyperoxia), (2) EMAP II delivery, and (3) BPD with neutralizing EMAP II antibody treatments. Chemokinic function of EMAP II and its neutralization were assessed by migration in vitro and in vivo. We determined the location of EMAP II by immunohistochemistry, pulmonary proinflammatory and chemotactic gene expression by quantitative polymerase chain reaction and immunoblotting, lung outcome by pulmonary function testing and histological analysis, and right ventricular hypertrophy by Fulton's Index. In BPD, EMAP II initially is a bronchial club-cell-specific protein-derived factor that later is expressed in galectin-3⁺ macrophages as BPD progresses. Continuous elevated expression corroborates with baboon and human BPD. Prolonged elevation of EMAP II levels recruits galectin-3⁺ macrophages, which is followed by an inflammatory state that resembles a severe BPD phenotype characterized by decreased pulmonary compliance, arrested alveolar development, and signs of pulmonary hypertension. In vivo pharmacological EMAP II inhibition suppressed proinflammatory genes Tnfa, Il6, and Il1b and chemotactic genes Ccl2 and Ccl9 and reversed the severe BPD phenotype. EMAP II is sufficient to induce macrophage recruitment, worsens BPD progression, and represents a targetable mechanism of BPD development.

Augmentation of response to nab-paclitaxel by inhibition of insulin-like growth factor (IGF) signaling in preclinical pancreatic cancer models

Nab-paclitaxel has recently shown greater efficacy in pancreatic ductal adenocarcinoma (PDAC). Insulin like growth factor (IGF) signaling proteins are frequently overexpressed in PDAC and correlate with aggressive tumor phenotype and poor prognosis. We evaluated the improvement in nab-paclitaxel response by addition of BMS-754807, a small molecule inhibitor of IGF-1R/IR signaling, in preclinical PDAC models. In subcutaneous xenografts using AsPC-1 cells, average net tumor growth in different therapy groups was 248.3 mm3 in controls, 42.4 mm3 after nab-paclitaxel (p = 0.002), 93.3 mm3 after BMS-754807 (p = 0.01) and 1.9 mm3 after nab-paclitaxel plus BMS-754807 (p = 0.0002). In subcutaneous xenografts using Panc-1 cells, average net tumor growth in different therapy groups was: 294.3 mm3 in controls, 23.1 mm3 after nab-paclitaxel (p = 0.002), 118.2 mm3 after BMS-754807 (p = 0.02) and -87.4 mm3 (tumor regression) after nab-paclitaxel plus BMS-754807 (p = 0.0001). In peritoneal dissemination model using AsPC-1 cells, median animal survival was increased compared to controls (21 days) after therapy with nab-paclitaxel (40 days, a 90% increase, p = 0.002), BMS-754807 (27 days, a 29% increase, p = 0.01) and nab-paclitaxel plus BMS-754807 (47 days, a 124% increase, p = 0.005), respectively. Decrease in proliferation and increase in apoptosis by nab-paclitaxel and BMS-754807 therapy correlated with their in vivo antitumor activity. In vitro analysis revealed that the addition of IC25 dose of BMS-754807 decreased the nab-paclitaxel IC50 of PDAC cell lines. BMS-754807 therapy decreased phospho-IGF-1R/IR and phospho-AKT expression, and increased cleavage of caspase-3 and PARP-1. These results support the potential of BMS-754807 in combination with nab-paclitaxel as an effective targeting option for pancreatic cancer therapy.

Abstract 276: Enhancing standard chemotherapy response by targeted inhibition of MAPK signaling pathways in experimental pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) has the worst prognosis of all solid tumors, with an overall survival rate of less than 6%. Gemcitabine (Gem) remained the standard of care agent over the past 16 years despite limited clinical benefits. Nab-paclitaxel (NPT), a water-soluble albumin-bound formulation of paclitaxel, has recently shown greater efficacy in advanced PDAC. Nab-paclitaxel combination with gemcitabine is now standard of care for advanced PDAC. More than 90% of PDAC tumors harbor an activating mutation in the KRAS oncogene. Since to date no therapeutics have effectively targeted this oncogene product, alternative strategies focus on inhibition of downstream effectors of KRAS signaling pathways. Trametinib (Tra) is a small molecule inhibitor of the RAF-MEK-ERK (MAPK) signaling pathway that is a well-described mediator of KRAS induced transformation and tumorigenesis. In the present preclinical study, we evaluated combination treatment benefits of the standard chemotherapeutics with trametinib to define a novel therapeutic strategy for PDAC.

Median animal survival over controls (20 days) in human intraperitoneal PDAC xenografts was significantly improved by NPT (33 days, a 65% increase, p = 0.0004), Gem (26 days, a 30% increase, p = 0.002), NPT+Gem (39 days, a 95% increase, p = 0.0001) and Tra (31 days, a 55% increase, p = 0.0004) therapy. Survival was further increased by addition of trametinib to chemotherapy: NPT+Tra (median: 37 days, a 85% increase, p = 0.0001), Gem+Tra (34 days, a 70% increase, p = 0.0001) and NPT+Gem+Tra (49 days, a 145% increase, p&lt;0.0001). Treatment of subcutaneous tumor-bearing mice with chemotherapy and trametinib resulted in significant tumor growth inhibition. Net tumor growth in different therapy groups over two weeks varied between controls (432.6 mm3), NPT (105.3 mm3), Tra (184 mm3), NPT+Tra (81 mm3), NPT+Gem (37.3 mm3), and NPT+Gem+Tra (-8.1 mm3). Mean tumor weight (in g) in different therapy groups was as follows: controls 0.38±0.06, NPT 0.23±0.06, Tra 0.31±0.03, NPT+Tra 0.23±0.06, NPT+Gem 0.15±0.05 and NPT+Gem+Tra 0.11±0.05. In vitro studies demonstrated inhibition in PDAC cell (AsPC-1, Panc-1, Mia PaCa-2, CFPAC) proliferation by treatment with NPT+Gem, trametinib, and combination. Immunoblot analysis revealed that trametinib effects were accompanied by decrease in phospho-ERK expression and increase in the expression of apoptosis-related cleaved caspase-3 protein. These findings suggest that the effects of the standard chemotherapeutic regimens can be enhanced through specific inhibition of downstream components of the MAPK signaling pathway, which clinically could lead to improved PDAC therapy effects.

Citation Format: Niranjan Awasthi, Sheena Monahan, Margaret A. Schwarz, Roderich E. Schwarz. Enhancing standard chemotherapy response by targeted inhibition of MAPK signaling pathways in experimental pancreatic cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 276.

Abstract 1258: Therapeutic potential of the cyclin- dependent kinase inhibitor on c-Myc overexpressing esophageal adenocarcinoma

Introduction: Esophageal adenocarcinoma (EAC) is now the fastest growing cancer in the western world and most EAC patients present with widespread metastatic disease, where current treatment is largely ineffective. Therefore, new therapeutic approaches are urgently needed. The transcription factor proto-oncogene c-Myc is a potent activator of tumorigenesis. Tumors with elevated c-Myc expression often exhibit highly aggressive phenotype. c-Myc amplification has been shown to be frequent in esophageal adenocarcinoma and has been implicated in Barrett's carcinogenesis. Emerging data suggests that synthetic lethal interactions between c-Myc pathway activation and small molecules inhibition involved in cell cycle signaling can be therapeutically exploited to preferentially kill tumor cells. In this study, we therefore investigated whether exploiting a synthetic-lethal approach dependent on elevated c-Myc signaling is effective in treating esophageal cancer with a cyclin-dependent kinase (CDK) inhibitor flavopiridol. Methods: Western blot analysis was done to see the expression of c-Myc and apoptotic signaling pathways in a panel of nine esophageal cancer cell lines. c-Myc overexpression and knockdown were performed using both genetic and novel chemical approaches. Cell viability assays were performed in 96-well plates using the colorimetric WST-1 reagent. Esophageal cancer tumors growth was measured in xenograft and a novel peritoneal disseminated metastatic survival model of immunodeficient mice. Results: Western blot analysis revealed frequent overexpression of c-Myc in EAC cell lines. In this panel of esophageal cancer cell lines tested more than 70% of EAC cell lines showed overexpression of c-Myc. When we tested these cell lines for their ability to form xenograft tumor and peritoneal dissemination, c-Myc overexpression correlated with accelerated EAC tumor growth in xenograft and peritoneal disseminated metastatic survival model of NOD/SCID mice. The xenograft tumor growth rate and formation rate of peritoneal cancer after injection of 5 million cells were highest in OE19 EAC cell line which showed the highest c-Myc expression. In addition, median animal survival with peritoneal dissemination was lowest for OE19 (55 days) whereas OACM5.1 C EAC cell line which had the lowest c-Myc expression didn't form any peritoneal tumor. EAC cell lines with elevated c-Myc expression are preferentially more sensitive to induction of apoptosis by CDK inhibitor flavopiridol compared to EAC cell lines with lower c-Myc expression. When we tested the role of c-Myc expression by upregulation/downregulation in this apoptotic effect we found that this effect is very much dependent on c-Myc expression. Conclusion: These results indicate that CDK inhibitor alone or in combination with other cytotoxic or targeted agents can be a potential therapy for c-Myc overexpressing EAC.

Citation Format: Sazzad Hassan, Niranjan Awasthi, Margaret A. Schwarz, Roderich E. Schwarz, Urs V. Holzen. Therapeutic potential of the cyclin- dependent kinase inhibitor on c-Myc overexpressing esophageal adenocarcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1258.

Profile of nintedanib in the treatment of solid tumors: the evidence to date

Angiogenesis is an essential process for tumor growth and metastasis, and remains a promising therapeutic target process in cancer treatment for several cancer types. Bevacizumab, a monoclonal antibody that targets vascular endothelial growth factor (VEGF), was the first antiangiogenic agent approved for cancer therapy. Novel antiangiogenic agents, such as sunitinib, sorafenib, pazopanib, or vandetanib that target additional proangiogenic signaling pathways beyond VEGF, have also been approved for the treatment of various malignant diseases. While most of these agents are approved in combination with cytotoxic chemotherapy for indications including metastatic colorectal cancer, non-small-cell lung cancer, breast cancer, renal cell carcinoma (RCC), and gastric cancer, some are used as approved monotherapy for advanced RCC, hepatocellular carcinoma and medullary thyroid cancer. Major challenges to the success of antiangiogenic therapy include associated toxicity risks, limitation of efficacy through the possible development of resistance and induction or promotion of metastatic progression. Nintedanib (formally known as BIBF 1120) is a triple angiokinase inhibitor of VEGF, fibroblast growth factor, platelet-derived growth factor signaling with lesser activity against RET, Flt-3, and Src. Through this unique targeting profile nintedanib has demonstrated significant antitumor activity in several tumor types in preclinical studies. Nintedanib has also shown promising clinical efficacy in combination with docetaxel and has been approved for treating patients with locally advanced and metastatic non-small-cell lung cancer in Europe. Nintedanib has also been found to be clinically promising in terms of efficacy and safety in several other solid tumors including ovarian cancer (Phase III), RCC (Phase II), and prostate cancer (Phase II). This review article provides a comprehensive summary of the preclinical and clinical efficacy of nintedanib in the treatment of solid tumors.

Abstract 3491: Enhancing nab-paclitaxel antitumor activity through addition of BMS-754807, a small-molecule inhibitor of IGF-1R/IR, in experimental pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer-related death in the United States, and is expected to become the second-leading cause of cancer death by 2030. Gemcitabine, the standard of care agent over the past 16 years, has limited clinical benefits. Recently, nab-paclitaxel has shown greater efficacy against advanced PDAC in combination with gemcitabine. Our lab has demonstrated superior antitumor activity of nab-paclitaxel compared with gemcitabine or docetaxel in preclinical PDAC studies. Insulin like growth factor (IGF) signaling proteins are frequently overexpressed in PDAC and correlate with aggressive tumor phenotype and poor prognosis indicating that the IGF system is an important therapeutic target in PDAC patients. BMS-754807, a small molecule inhibitor of IGF-type 1 receptor (IGF-1R) and insulin receptor (IR), has shown efficacy in PDAC. We evaluated combination treatment benefits of nab-paclitaxel with BMS-754807 in experimental PDAC.

In vitro cell proliferation and protein expression were measured by WST-1 assay and immunoblotting. Heterotopic tumor growth and animal survival experiments were performed in murine xenografts.

In vitro analysis of four PDAC cell lines (AsPC-1, BxPC-3, MIA PaCa-2, Panc-1) revealed that single agent nab-paclitaxel and BMS-754807 both inhibited cell proliferation in a dose-dependent manner. To evaluate the combination treatment benefits of nab-paclitaxel and BMS-754807, the IC25 dose of BMS-754807 was combined with increasing doses of nab-paclitaxel. Addition of BMS-754807 decreased the nab-paclitaxel IC50 from 7.2 μM to 490 nM for AsPC-1, 430 nM to 50 nM for BxPC-3, 740 nM to 540 nM for MIA PaCa-2, and 690 nM to 280 nM for Panc-1 cell lines. These data suggest that BMS-754807 combines well with nab-paclitaxel and efficiently decreases the nab-paclitaxel IC50 in PDAC cell lines. In a heterotopic AsPC-1 PDAC model, relative to controls (100±21.3), percent net local tumor growth was 17.1±21.1 with nab-paclitaxel (p = 0.002), 37.6±16.2 with BMS-754807 (p = 0.01) and 0.76±9.1 with nab-paclitaxel plus BMS-754807 (p = 0.0002). In Panc-1 subcutaneous xenografts, compared with controls (100±31.5), percent net tumor growth was 7.8±27.2 with nab-paclitaxel (p = 0.002), 40.2±24.1 with BMS-754807 (p = 0.02) and -29.7±16.8 with nab-paclitaxel plus BMS-754807 (p = 0.0001). In an animal survival study, median animal survival was increased compared to controls (21 days) after nab-paclitaxel therapy (40 days, a 90% increase, p = 0.002), BMS-754807 therapy (27 days, a 29% increase, p = 0.01), and nab-paclitaxel plus BMS-754807 therapy (47 days, a 124% increase, p = 0.005).

These results highlight measurable antitumor activity of BMS-754807 in experimental PDAC and support the potential of BMS-754807 in combination with nab-paclitaxel as promising targeted therapy for clinical pancreatic cancer therapy.

Citation Format: Niranjan Awasthi, Margaret A. Schwarz, Roderich E. Schwarz. Enhancing nab-paclitaxel antitumor activity through addition of BMS-754807, a small-molecule inhibitor of IGF-1R/IR, in experimental pancreatic cancer. [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 3491. doi:10.1158/1538-7445.AM2015-3491

A Phase I Dose-Escalation Trial of Single-Fraction Stereotactic Radiation Therapy for Liver Metastases

Background

There is significant interest in the use of stereotactic ablative radiotherapy (SABR) as a treatment modality for liver metastases. A variety of SABR fractionation schemes are in clinical use. We conducted a phase I dose-escalation study to determine the maximum tolerated dose of single-fraction liver SABR.

Methods

Patients with liver metastases from solid tumors, for whom a critical volume dose constraint could be met, were treated with single-fraction SABR. Seven patients were enrolled to the first group, with a prescription dose of 35 Gy. Dose was then escalated to 40 Gy in a single fraction, and seven more patients were treated at this dose level. Patients were followed for toxicity and underwent serial imaging to assess lesion response and local control.

Results

Fourteen patients with 17 liver metastases were treated. There were no dose-limiting toxicities observed at either dose level. Nine of the 13 lesions assessable for treatment response showed a complete radiographic response to treatment; the remainder showed partial response. Local control of irradiated lesions was 100 % at a median imaging follow-up of 2.5 years. Two-year overall survival for all patients was 78 %.

Conclusions

For selected patients with liver metastases, single-fraction SABR at doses of 35 and 40 Gy is tolerable and shows promising signs of efficacy at intermediate follow-up.

Current status of management of malignant disease: current management of gastric cancer

Despite a continually decreasing incidence trend, gastric cancer remains a high-risk malignancy. Symptoms are often unspecific, and upper gastrointestinal endoscopy is the key modality for diagnosing early and intermediate-stage disease. Surgeons play a critical role in guiding and managing multiple aspects of gastric cancer diagnosis and care. Potentially curable gastric adenocarcinoma has to be free of distant metastasis and should be staged through endoscopic ultrasound and computed tomography. Early (T1N0) gastric cancer can be considered for endosopic mucosal resection or submucosal dissection. All other M0 stage groups should be evaluated for preoperative chemotherapy or chemoradiation followed by resection through a multidisciplinary approach. Laparoscopic staging, complete (R0) resection, and extended lymphadenectomy (D2 dissection) are critical operative components that optimize curability during gastrectomy. The morbidity potential after gastrectomy remains high; splenectomy and distal pancreatectomy should be avoided if possible to minimize postoperative complications. Laparoscopic gastric cancer resections are increasingly pursued and have not shown disadvantages to open gastrectomy as long as oncologic principles are followed. For the palliation of specific symptoms in patients with incurable gastric cancer, operative interventions should be applied selectively if less invasive modalities are insufficient and only if a meaningful benefit can be expected from a resection or bypass procedure. Prophylactic total gastrectomy should be considered for individuals at risk for hereditary diffuse-type gastric cancer through germline E-cadherin gene mutations. Surgeons engaging in gastric cancer care are expected to provide specialty expertise in order to plan and deliver appropriate care, minimize postoperative morbidity, and optimize resulting survival.

The N terminus of pro-endothelial monocyte-activating polypeptide II (EMAP II) regulates its binding with the C terminus, arginyl-tRNA synthetase, and neurofilament light protein

Pro-endothelial monocyte-activating polypeptide II (EMAP II), one component of the multi-aminoacyl tRNA synthetase complex, plays multiple roles in physiological and pathological processes of protein translation, signal transduction, immunity, lung development, and tumor growth. Recent studies have determined that pro-EMAP II has an essential role in maintaining axon integrity in central and peripheral neural systems where deletion of the C terminus of pro-EMAP II has been reported in a consanguineous Israeli Bedouin kindred suffering from Pelizaeus-Merzbacher-like disease. We hypothesized that the N terminus of pro-EMAP II has an important role in the regulation of protein-protein interactions. Using a GFP reporter system, we defined a putative leucine zipper in the N terminus of human pro-EMAP II protein (amino acid residues 1-70) that can form specific strip-like punctate structures. Through GFP punctum analysis, we uncovered that the pro-EMAP II C terminus (amino acids 147-312) can repress GFP punctum formation. Pulldown assays confirmed that the binding between the pro-EMAP II N terminus and its C terminus is mediated by a putative leucine zipper. Furthermore, the pro-EMAP II 1-70 amino acid region was identified as the binding partner of arginyl-tRNA synthetase, a polypeptide of the multi-aminoacyl tRNA synthetase complex. We also determined that the punctate GFP pro-EMAP II 1-70 amino acid aggregate colocalizes and binds to the neurofilament light subunit protein that is associated with pathologic neurofilament network disorganization and degeneration of motor neurons. These findings indicate the structure and binding interaction of pro-EMAP II protein and suggest a role of this protein in pathological neurodegenerative diseases.

Experience with a simple clamp-crush technique devoid of other devices for liver resections in a surgical oncology practice

BACKGROUND

Parenchyma transection techniques during liver resection (LR) are linked to intraoperative blood loss and postoperative morbidity, with a recent increased use of energy devices over traditional clamp-crush hepatotomy (CCH).

METHODS

Prospectively collected data from 191 consecutive patients undergoing LR with exclusive CCH by a single surgeon were examined.

RESULTS

There were 94 men and 97 women, with 25% primary and 59% secondary malignancies or other conditions (16%). Forty-nine percent of LRs were major, 65% anatomic, and 32% included extrahepatic components. Median Pringle time was 23 minutes (9 to 76), blood loss 300 mL (20 to 5,000), and red blood cell transfusion rate 14%. Morbidity rate was 27% with 6 deaths. Significant relationships were observed for blood loss with complex resections, transfusions, major morbidity, and length of stay, but not between Pringle time and any outcomes.

CONCLUSION

A CCH technique as employed in this LR experience without any use of additional devices can yield good postoperative results.