Effect of Hyperthermic Intraperitoneal Chemotherapy on Cytoreductive Surgery in Gastric Cancer With Synchronous Peritoneal Metastases: The Phase III GASTRIPEC-I Trial

PURPOSE

In patients with peritoneal metastasis (PM) from gastric cancer (GC), chemotherapy is the treatment of choice. Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) are still being debated. This randomized, controlled, open-label, multicenter phase III trial (EudraCT 2006-006088-22; ClinicalTrials.gov identifier: NCT02158988) explored the impact on overall survival (OS) of HIPEC after CRS.

PATIENTS AND METHODS

Adult patients with GC and histologically proven PM were randomly assigned (1:1) to perioperative chemotherapy and CRS alone (CRS-A) or CRS plus HIPEC (CRS + H). HIPEC comprised mitomycin C 15 mg/m2 and cisplatin 75 mg/m2 in 5 L of saline perfused for 60 minutes at 42°C. The primary end point was OS; secondary endpoints included progression-free survival (PFS), other distant metastasis-free survival (MFS), and safety. Analyses followed the intention-to-treat principle.

RESULTS

Between March 2014 and June 2018, 105 patients were randomly assigned (53 patients to CRS-A and 52 patients to CRS + H). The trial stopped prematurely because of slow recruitment. In 55 patients, treatment stopped before CRS mainly due to disease progression/death. Median OS was the same for both groups (CRS + H, 14.9 [97.2% CI, 8.7 to 17.7] months v CRS-A, 14.9 [97.2% CI, 7.0 to 19.4] months; P = .1647). The PFS was 3.5 months (95% CI, 3.0 to 7.0) in the CRS-A group and 7.1 months (95% CI, 3.7 to 10.5; P = .047) in the CRS + H group. The CRS + H group showed better MFS (10.2 months [95% CI, 7.7 to 14.7] v CRS-A, 9.2 months [95% CI, 6.8 to 11.5]; P = .0286). The incidence of grade ≥3 adverse events (AEs) was similar between groups (CRS-A, 38.1% v CRS + H, 43.6%; P = .79).

CONCLUSION

This study showed no OS difference between CRS + H and CRS-A. PFS and MFS were significantly better in the CRS + H group, which needs further exploration. HIPEC did not increase AEs.

Demystifying BRAF Mutation Status in Colorectal Liver Metastases : A Multi-institutional, Collaborative Approach to 6 Open Clinical Questions

OBJECTIVE

To investigate the clinical implications of BRAF -mutated (mut BRAF ) colorectal liver metastases (CRLMs).

BACKGROUND

The clinical implications of mut BRAF status in CRLMs are largely unknown.

METHODS

Patients undergoing resection for mut BRAF CRLM were identified from prospectively maintained registries of the collaborating institutions. Overall survival (OS) and recurrence-free survival (RFS) were compared among patients with V600E versus non-V600E mutations, KRAS/BRAF comutation versus mut BRAF alone, microsatellite stability status (Microsatellite Stable (MSS) vs instable (MSI-high)), upfront resectable versus converted tumors, extrahepatic versus liver-limited disease, and intrahepatic recurrence treated with repeat hepatectomy versus nonoperative management.

RESULTS

A total of 240 patients harboring BRAF -mutated tumors were included. BRAF V600E mutation was associated with shorter OS (30.6 vs 144 mo, P =0.004), but not RFS compared with non-V600E mutations. KRAS/BRAF comutation did not affect outcomes. MSS tumors were associated with shorter RFS (9.1 vs 26 mo, P <0.001) but not OS (33.5 vs 41 mo, P =0.3) compared with MSI-high tumors, whereas patients with resected converted disease had slightly worse RFS (8 vs 11 mo, P =0.01) and similar OS (30 vs 40 mo, P =0.4) compared with those with upfront resectable disease. Patients with extrahepatic disease had worse OS compared with those with liver-limited disease (8.8 vs 40 mo, P <0.001). Repeat hepatectomy after intrahepatic recurrence was associated with improved OS compared with nonoperative management (41 vs 18.7 mo, P =0.004). All results continued to hold true in the multivariable OS analysis.

CONCLUSIONS

Although surgery may be futile in patients with BRAF -mutated CRLM and concurrent extrahepatic disease, resection of converted disease resulted in encouraging survival in the absence of extrahepatic spread. Importantly, second hepatectomy in select patients with recurrence was associated with improved outcomes. Finally, MSI-high status identifies a better prognostic group, with regard to RFS while patients with non-V600E mutations have excellent prognosis.

Near-infrared Fluorescence Imaging for Detecting Pancreatic Liver Metastasis in an Orthotopic Athymic Mouse Model

BACKGROUND/AIM

Evidence of metastatic disease precludes oncological resection of pancreatic cancer. Near-infrared (NIR) fluorescent labels, such as indocyanine green (ICG), assist in the intraoperative detection of occult and micrometastatic liver disease. The present study aimed to analyse the role of NIR fluorescence imaging using ICG for pancreatic liver disease as proof of concept in an orthotopic athymic mouse model.

MATERIALS AND METHODS

Pancreatic ductal adenocarcinoma was induced by injecting L3.6pl human pancreatic tumour cells into the pancreatic tail of seven athymic mice. After four weeks of tumour growth, ICG was injected into the tail vein and NIR fluorescence imaging was performed at harvest to determine tumour-to-liver ratios (TLR) using Quest Spectrum^® Fluorescence Imaging Platform.

RESULTS

Pancreatic tumour growth and liver metastasis could be visually confirmed for all seven animals. None of the hepatic metastases showed any detectable ICG-uptake. ICG-staining failed to visualize the liver metastases or to increase fluorescence intensity of the rim around the hepatic lesions.

CONCLUSION

ICG-staining fails to visualize liver metastases induced by L3.6pl pancreatic tumour cells in athymic nude mice by NIR fluorescence imaging. Further studies are necessary to delineate the underlying mechanism for insufficient ICG uptake in these pancreatic liver metastases and for the lack of a fluorescent rim around the liver lesions.

Gp130 is expressed in pancreatic cancer and can be targeted by the small inhibitor molecule SC144

PURPOSE

Interleukin 6 (IL-6), Oncostatin M (OSM), and downstream effector STAT3 are pro-tumorigenic agents in pancreatic ductal adenocarcinoma (PDAC). Glycoprotein 130 (gp130) is a compound of the IL-6 and OSM receptor complex that triggers STAT3 signaling. SC144 is a small molecule gp130 inhibitor with anticancer activity. This study examines the gp130 expression in human PDAC specimens and the in vitro effects of SC144 in PDAC cell lines.

METHODS

Tissue micro-arrays were constructed from 175 resected human PDAC. The gp130 expression in tumor epithelium and stroma was determined by immunohistochemistry, and survival analysis was performed. Growth inhibition by SC144 was assessed in vitro using BrdU and MTT assays. Western blotting was performed to evaluate the SC144 effect on IL-6 and OSM signaling.

RESULTS

Gp130 was expressed in the epithelium of 78.8% and the stroma of 9.4% of the tumor samples. The median overall survival for patients with or without epithelial gp130 expression was 16.7 months and 15.9 months, respectively (p = 0.830). Patients with no stromal gp130 expression showed poorer survival than patients with stromal gp130 expression (median 16.2 and 22.9 months, respectively), but this difference did not reach significance (p = 0.144). SC144 inhibited cell proliferation and viability and suppressed IL-6- and OSM-stimulated STAT3^Y705 phosphorylation in PDAC cells.

CONCLUSION

Gp130 is expressed in the epithelium of most human PDAC, but stromal expression is rare. The small molecule gp130 inhibitor SC144 potently inhibits PDAC progression in vitro and may abrogate IL-6 or OSM/gp130/STAT3 signaling. These results suggest gp130 as a novel drug target for pancreatic cancer therapy.

Prognostic value of primary tumor sidedness in patients with non-metastatic IBD related CRC - Is it the exception to the rule?

BACKGROUND

Although primary tumor sidedness (PTS) has a known prognostic role in sporadic colorectal cancer (CRC), its role in Inflammatory Bowel Disease related CRC (IBD-CRC) is largely unknown. Thus, we aimed to evaluate the prognostic role of PTS in patients with IBD-CRC.

METHODS

All eligible patients with surgically treated, non-metastatic IBD-CRC were retrospectively identified from institutional databases at ten European and Asian academic centers. Long term endpoints included recurrence-free (RFS) and overall survival (OS). Multivariable Cox proportional hazard regression as well as propensity score analyses were performed to evaluate whether PTS was significantly associated with RFS and OS.

RESULTS

A total of 213 patients were included in the analysis, of which 32.4% had right-sided (RS) tumors and 67.6% had left-sided (LS) tumors. PTS was not associated with OS and RFS even on univariable analysis (5-year OS for RS vs LS tumors was 68.0% vs 77.3%, respectively, p = 0.31; 5-year RFS for RS vs LS tumors was 62.8% vs 65.4%, respectively, p = 0.51). Similarly, PTS was not associated with OS and RFS on propensity score matched analysis (5-year OS for RS vs LS tumors was 82.9% vs 91.3%, p = 0.79; 5-year RFS for RS vs LS tumors was 85.1% vs 81.5%, p = 0.69). These results were maintained when OS and RFS were calculated in patients with RS vs LS tumors after excluding patients with rectal tumors (5-year OS for RS vs LS tumors was 68.0% vs 77.2%, respectively, p = 0.38; 5-year RFS for RS vs LS tumors was 62.8% vs 59.2%, respectively, p = 0.98).

CONCLUSIONS

In contrast to sporadic CRC, PTS does not appear to have a prognostic role in IBD-CRC.

Frequency of Positive Familial Criteria in Patients with Adenocarcinoma of the Esophageal-Gastric Junction and Stomach: First Prospective Data in a Caucasian Cohort

Simple Summary

It is well known for gastric cancer patients with subtype of diffuse histology that a proportion of patients harbour an increased familial risk. Some patients and relatives even may be detected through a genetic testing. More precise studies about the frequency of hereditary criteria in a poplation with only European ancestries for adenocarcinoma of the esophagogastric junction and stomach are missing. In current guidelines regarding genetic testing criteria not all types of stomach cancer are considered as for example patients not with subtype of diffuse histology mostly have no detectable responsible gene. The aim of the current study was to register stomach cancer patients of all different types in a certain region (Berlin, Germany) and to estimate the frequency of positive familial criteria. Patients with esophageal cancer served as comparison group as familial or hereditary background, respectively, is not significant in these patients according to current knowledge. In our study, we identified positive familial criteria in about 15% of stomach cancer patients. In regard to all different types of stomach cancer, this number almost doubled. Furthermore, one third of all registered patients in this study might have a familial or hereditary background of their disease. We therefore conclude that guidelines regarding genetic testing criteria and screening examinations should be adjusted in future.

Abstract

Objectives: Current prospective studies investigating the frequency of hereditary criteria in a Caucasian population for adenocarcinoma of the esophagogastric junction (AEG) and stomach (GC) are missing. Genetic testing criteria (screening criteria) for hereditary diffuse gastric cancer (HDGC) were updated in 2020, but do not address patients with intestinal histology (familial intestinal gastric cancer FIGC). Thus, we prospectively screened patients residing in Berlin newly diagnosed with AEG or GC for hereditary criteria to gain insights into the frequency of HDGC. Methods: Prospective documentation of familial/clinical parameters in patients residing in Berlin with AEG or GC over three years was conducted. Besides HDGC criteria from 2015 and revised 2020, we also documented patients fulfilling these criteria but with intestinal type gastric cancer (FIGC). Statistical analysis was performed using X2-test. Results: One hundred fifty-three patients were finally included (92 GC; male: 50 (n.s.); 61 AEG; male: 47; p = 0.007). Hereditary criteria for HDGC were detected in 9/92 (9.8%) (2015 criteria) and in 14/92 (15.2%) (2020 criteria) of GC patients (AEG: 2015 criteria 3/61 (4.9%) versus 4/61 according to 2020 criteria (6.5%)). Patients fulfilling hereditary criteria but with intestinal histology (FIGC) increased from 8.7% (2015) to 14.1%, respectively (2020) (AEG: 3.2% (2015) versus 6.6% (2020)). Hereditary criteria including intestinal histology were found in 29.3% (GC) and 13.1% (AEG) (p = 0.03) according to the 2020 criteria. Conclusions: HDGC criteria were found in 15.2% of GC patients according to the 2020 criteria. Percentage increased to 29.3% including patients with intestinal histology among the GC group, and was 13.1% in cases with AEG. These data indicate that family history seems to be of utmost importance in GC to further detect potential hereditary genetic risks. This equally applies for patients with intestinal subtype GC.

Using Artificial Intelligence to Find the Optimal Margin Width in Hepatectomy for Colorectal Cancer Liver Metastases

Importance

In patients with resectable colorectal cancer liver metastases (CRLM), the choice of surgical technique and resection margin are the only variables that are under the surgeon's direct control and may influence oncologic outcomes. There is currently no consensus on the optimal margin width.

Objective

To determine the optimal margin width in CRLM by using artificial intelligence-based techniques developed by the Massachusetts Institute of Technology and to assess whether optimal margin width should be individualized based on patient characteristics.

Design, Setting, and Participants

The internal cohort of the study included patients who underwent curative-intent surgery for KRAS-variant CRLM between January 1, 2000, and December 31, 2017, at Johns Hopkins Hospital, Baltimore, Maryland, Memorial Sloan Kettering Cancer Center, New York, New York, and Charité-University of Berlin, Berlin, Germany. Patients from institutions in France, Norway, the US, Austria, Argentina, and Japan were retrospectively identified from institutional databases and formed the external cohort of the study. Data were analyzed from April 15, 2019, to November 11, 2021.

Exposures

Hepatectomy.

Main Outcomes and Measures

Patients with KRAS-variant CRLM who underwent surgery between 2000 and 2017 at 3 tertiary centers formed the internal cohort (training and testing). In the training cohort, an artificial intelligence-based technique called optimal policy trees (OPTs) was used by building on random forest (RF) predictive models to infer the margin width associated with the maximal decrease in death probability for a given patient (ie, optimal margin width). The RF component was validated by calculating its area under the curve (AUC) in the testing cohort, whereas the OPT component was validated by a game theory-based approach called Shapley additive explanations (SHAP). Patients from international institutions formed an external validation cohort, and a new RF model was trained to externally validate the OPT-based optimal margin values.

Results

This cohort study included a total of 1843 patients (internal cohort, 965; external cohort, 878). The internal cohort included 386 patients (median [IQR] age, 58.3 [49.0-68.7] years; 200 men [51.8%]) with KRAS-variant tumors. The AUC of the RF counterfactual model was 0.76 in both the internal training and testing cohorts, which is the highest ever reported. The recommended optimal margin widths for patient subgroups A, B, C, and D were 6, 7, 12, and 7 mm, respectively. The SHAP analysis largely confirmed this by suggesting 6 to 7 mm for subgroup A, 7 mm for subgroup B, 7 to 8 mm for subgroup C, and 7 mm for subgroup D. The external cohort included 375 patients (median [IQR] age, 61.0 [53.0-70.0] years; 218 men [58.1%]) with KRAS-variant tumors. The new RF model had an AUC of 0.78, which allowed for a reliable external validation of the OPT-based optimal margin. The external validation was successful as it confirmed the association of the optimal margin width of 7 mm with a considerable prolongation of survival in the external cohort.

Conclusions and Relevance

This cohort study used artificial intelligence-based methodologies to provide a possible resolution to the long-standing debate on optimal margin width in CRLM.

Thymidine phosphorylase induction by ionizing radiation antagonizes 5-fluorouracil resistance in human ductal pancreatic adenocarcinoma

Chemoresistance in pancreatic ductal adenocarcinoma (PDAC) frequently contributes to failure of systemic therapy. While the radiosensitizing properties of 5-fluorouracil (FU) are well known, it is unknown whether ionizing radiation (IR) sensitizes towards FU cytotoxicity. Here, we hypothesize that upregulation of thymidine phosphorylase (TP) by IR reverses FU chemoresistance in PDAC cells. The FU resistant variant of the human PDAC cell line AsPC-1 (FU-R) was used to determine the sensitizing effects of IR. Proliferation rates of FU sensitive parental (FU-S) and FU-R cells were determined by WST-1 assays after low (0.05 Gy) and intermediate dose (2.0 Gy) IR followed by FU treatment. TP protein expression in PDAC cells before and after IR was assessed by Western blot. To analyze the specificity of the FU sensitizing effect, TP was ablated by siRNA. FU-R cells showed a 2.7-fold increase of the half maximal inhibitory concentration, compared to FU-S parental cells. Further, FU-R cells showed a concomitant IR resistance towards both doses applied. When challenging both cell lines with FU after IR, FU-R cells had lower proliferation rates than FU-S cells, suggesting a reversal of chemoresistance by IR. This FU sensitizing effect was abolished when TP was blocked by anti-TP siRNA before IR. An increase of TP protein expression was seen after both IR doses. Our results suggest a TP dependent reversal of FU-chemoresistance in PDAC cells that is triggered by IR. Thus, induction of TP expression by low dose IR may be a therapeutic approach to potentially overcome FU chemoresistance in PDAC.

Is Laterality Prognostic in Resected KRAS-Mutated Colorectal Liver Metastases? A Systematic Review and Meta-Analysis

Simple Summary

Primary tumor laterality (PTL) is the most recently identified prognostic factor associated with mortality in patients with resected colorectal cancer liver metastases, but whether it is prognostic in all patients or only those with wild-type KRAS tumors is debated. The aim of this meta-analysis was to identify all relevant articles and synthesize their evidence to estimate the effect of PTL per KRAS mutational status. We found that PTL and KRAS mutational status have a statistically significant interaction. Specifically, PTL has a variable effect in patients with wild-type versus KRAS-mutated tumors, with right-sided tumors associated with worse survival only in the former. This meta-analysis appears to resolve a long-lasting debate.

Abstract

Background: It is debated whether primary tumor laterality (PTL) is prognostic in all patients with colorectal liver metastases (CRLM) or only those with KRAS wild-type or KRAS-mutated tumors; Methods: We systematically reviewed PubMed for studies reporting on resected CRLM originating from left-sided (LS) versus right-sided (RS) colon cancer stratified by KRAS status. Individual participant data (IPD) were used if available. Given that there are two definitions of PTL, we performed two meta-analyses for KRAS-mutated and two for wild-type patients. To assess if an interaction underlies the possible difference between the effects of PTL in KRAS-mutated vs. wild-type CRLM, we similarly performed two meta-analyses of interaction terms; Results: The meta-analyses included eight studies and 7475 patients. PTL had a prognostic association with OS in patients with wild-type tumors (HR for LS: 0.71 [0.60–0.84]), but not in those with KRAS-mutated tumors (HR: 0.99 [0.82–1.19]). This difference stemmed from a truly variable effect of PTL for each KRAS status (mutated vs. wild-type) as the meta-analysis of interaction terms showed a significant interaction between them (HR:1.38 [1.24–1.53]). Similar results were obtained when the second definition of PTL (LS to not include the rectum) was used; Conclusions: KRAS status modifies the association of tumor site with survival. Right-sided tumors are associated with worse OS only in patients with wild-type CRLM.

Impact of myopenia and myosteatosis on postoperative outcome and recurrence in Crohn's disease

PURPOSE

Myopenia and myosteatosis have been proposed to be prognostic factors of surgical outcomes for various diseases, but their exact role in Crohn's disease (CD) is unknown. The aim of this study is to evaluate their impact on anastomotic leakage, CD recurrence, and postoperative complications after ileocecal resection in patients with CD.

METHODS

A retrospective analysis of CD patients undergoing ileocecal resection at our tertiary referral center was performed. To assess myopenia, skeletal muscle index (skeletal muscle area normalized for body height) was measured using an established image analysis method at third lumbar vertebra level on MRI cross-sectional images. Muscle signal intensity was measured to assess myosteatosis index.

RESULTS

A total of 347 patients were retrospectively analyzed. An adequate abdominal MRI scan within 12 months prior to surgery was available for 223 patients with median follow-up time of 48.8 months (IQR: 20.0-82.9). Anastomotic leakage rate was not associated with myopenia (SMI: p = 0.363) or myosteatosis index (p = 0.821). Patients with Crohn's recurrence had a significantly lower SMI (p = 0.047) in univariable analysis, but SMI was not an independent factor for recurrent anastomotic stenosis in multivariable analysis (OR 0.951, 95% CI 0.840-1.078; p = 0.434). Postoperative complications were not associated with myopenia or myosteatosis.

CONCLUSION

Based on the largest cohort of its kind with a long follow-up time, we could provide some data that MRI parameters for myopenia and myosteatosis may not be reliable predictors of postoperative outcome or recurrence in patients with Crohn's disease undergoing ileocecal resection.

Toward an Optimized Staging System for Pancreatic Ductal Adenocarcinoma: A Clinically Interpretable, Artificial Intelligence-Based Model

PURPOSE

The American Joint Committee on Cancer (AJCC) eighth edition schema for pancreatic ductal adenocarcinoma treats T and N stage as independent factors and uses positive lymph nodes (PLNs) to define N stage, despite data favoring lymph node ratio (LNR). We used artificial intelligence-based techniques to compare PLN with LNR and investigate interactions between tumor size and nodal status.

METHODS

Patients who underwent pancreatic ductal adenocarcinoma resection between 2000 and 2017 at six institutions were identified. LNR and PLN were compared through shapley additive explanations (SHAP) analysis, with the best predictor used to define nodal status. We trained optimal classification trees (OCTs) to predict 1-year and 3-year risk of death, incorporating only tumor size and nodal status as variables. The OCTs were compared with the AJCC schema and similarly trained XGBoost models. Variable interactions were explored via SHAP.

RESULTS

Two thousand eight hundred seventy-four patients comprised the derivation and 1,231 the validation cohort. SHAP identified LNR as a superior predictor. The OCTs outperformed the AJCC schema in the derivation and validation cohorts (1-year area under the curve: 0.681 v 0.603; 0.638 v 0.586, 3-year area under the curve: 0.682 v 0.639; 0.675 v 0.647, respectively) and performed comparably with the XGBoost models. We identified interactions between LNR and tumor size, suggesting that a negative prognostic factor partially overrides the effect of a concurrent favorable factor.

CONCLUSION

Our findings highlight the superiority of LNR and the importance of interactions between tumor size and nodal status. These results and the potential of the OCT methodology to combine them into a powerful, visually interpretable model can help inform future staging systems.

Raloxifene inhibits pancreatic adenocarcinoma growth by interfering with ERβ and IL-6/gp130/STAT3 signaling

PURPOSE

Currently, the exact role of estrogen receptor (ER) signaling in pancreatic cancer is unknown. Recently, we showed that expression of phosphorylated ERβ correlates with a poor prognosis in patients with pancreatic ductal adenocarcinoma (PDAC). Here, we hypothesized that raloxifene, a FDA-approved selective ER modulator (SERM), may suppress PDAC tumor growth by interfering with ERβ signaling. To test this hypothesis, we studied the impact of raloxifene on interleukin-6/glycoprotein-130/signal transducer and activator of transcription-3 (IL-6/gp130/STAT3) signaling.

METHODS

Human PDAC cell lines were exposed to raloxifene after which growth inhibition was assessed using a BrdU assay. ER knockdown was performed using siRNAs specific for ERα and ERβ. The effects of raloxifene on IL-6 expression and STAT3 phosphorylation in PDAC cells were assessed by ELISA and Western blotting, respectively. In addition, raloxifene was administered to an orthotopic PDAC tumor xenograft mouse model, after which tumor growth was monitored and immunohistochemistry was performed.

RESULTS

Raloxifene inhibited the in vitro growth of PDAC cells, and this effect was reversed by siRNA-mediated knockdown of ERβ, but not of ERα, indicating ER isotype-specific signaling. We also found that treatment with raloxifene inhibited the release of IL-6 and suppressed the phosphorylation of STAT3Y705 in PDAC cells. In vivo, we found that orthotopic PDAC tumor growth, lymph node and liver metastases as well as Ki-67 expression were reduced in mice treated with raloxifene.

CONCLUSIONS

Inhibition of ERβ and the IL-6/gp130/STAT3 signaling pathway by raloxifene leads to potent reduction of PDAC growth in vitro and in vivo. Our results suggest that ERβ signaling and IL-6/gp130 interaction may serve as promising drug targets for pancreatic cancer and that raloxifene may serve as an attractive therapeutic option for PDAC patients expressing the ERβ isotype.

Risk factors for upper and lower type prolonged postoperative ileus following surgery for Crohn's disease

PURPOSE

Prolonged postoperative ileus (PPOI) is common after bowel resections, especially in Crohn's disease (CD). The pathophysiology of PPOI is not fully understood. PPOI could affect only the upper or lower gastrointestinal (GI) tract. The aim of this study was to assess risk factors for diverse types of PPOI, particularly to differentiate PPOI of upper and lower GI tract.

METHODS

A retrospective analysis of 163 patients with CD undergoing ileocecal resection from 2015 to 2020 in a single center was performed. PPOI of the upper GI tract was predefined as the presence of vomiting or use of nasogastric tube longer than the third postoperative day. Lower PPOI was predefined as the absence of defecation for more than three days. Independent risk factors were identified by multivariable logistic regression analysis.

RESULTS

Overall incidence of PPOI was 42.7%. PPOI of the upper GI tract was observed in 30.7% and lower PPOI in 20.9% of patients. Independent risk factors for upper PPOI included older age, surgery by a resident surgeon, hand-sewn anastomosis, prolonged opioid analgesia, and reoperation, while for lower PPOI included BMI ≤ 25 kg/m², preoperative anemia, and absence of ileostomy.

CONCLUSION

This study identified different risk factors for upper and lower PPOI after ileocecal resection in patients with CD. A differentiated upper/lower type approach should be considered in future research and clinical practice. High-risk patients for each type of PPOI should be closely monitored, and modifiable risk factors, such as preoperative anemia and opioids, should be avoided if possible.

Accuracy of various criteria for lymph node staging in ductal adenocarcinoma of the pancreatic head by computed tomography and magnetic resonance imaging

BACKGROUND

Lymph node staging of ductal adenocarcinoma of the pancreatic head (PDAC) by cross-sectional imaging is limited. The aim of this study was to determine the diagnostic accuracy of expanded criteria in nodal staging in PDAC patients.

METHODS

Sixty-six patients with histologically confirmed PDAC that underwent primary surgery were included in this retrospective IRB-approved study. Cross-sectional imaging studies (CT and/or MRI) were evaluated by a radiologist blinded to histopathology. Number and size of lymph nodes were measured (short-axis diameter) and characterized in terms of expanded morphological criteria of border contour (spiculated, lobulated, and indistinct) and texture (homogeneous or inhomogeneous). Sensitivities and specificities were calculated with histopathology as a reference standard.

RESULTS

Forty-eight of 66 patients (80%) had histologically confirmed lymph node metastases (pN+). Sensitivity, specificity, and Youden's Index for the criterion "size" were 44.2%, 82.4%, and 0.27; for "inhomogeneous signal intensity" 25.6%, 94.1%, and 0.20; and for "border contour" 62.7%, 52.9%, and 0.16, respectively. There was a significant association between the number of visible lymph nodes on preoperative CT and lymph node involvement (pN+, p = 0.031).

CONCLUSION

Lymph node staging in PDAC is mainly limited due to low sensitivity for detection of metastatic disease. Using expanded morphological criteria instead of size did not improve regional nodal staging due to sensitivity remaining low. Combining specific criteria yields improved sensitivity with specificity and PPV remaining high.

Timing of surgery in ulcerative colitis in the biologic therapy era-the patient's perspective

BACKGROUND

There is no general consensus regarding the ideal timing of surgery in patients with refractory ulcerative colitis (UC). Decision-making and timing of restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA) is influenced by treating physicians and patients themselves. The aim of this study was to determine whether or not patients would have preferred the operation to be performed earlier, at the same time, or at a later point of time and to determine the reasons for their preference.

METHODS

Clinical data of 193 patients with UC who have undergone IPAA were documented in a prospective database at our institution between 2004 and 2015. From this database, 190 patients were identified and a standardized custom-made questionnaire was mailed for follow-up survey. Patients who did not respond were called by telephone and encouraged to complete the questionnaire.

RESULTS

One hundred nine questionnaires were eligible for analysis (57.4%). Average time between diagnosis and surgery was 11.2 ± 10.8 years (mean ± SD). Indications for surgery were refractory disease (70.6%), colitis-associated colorectal cancer (11.0%), high-grade dysplasia or stenosis (11.9%), and septic complications of UC (6.4%); 39 of 77 patients (50.6%) with refractory UC reported to have preferred their operation to be carried out earlier as it was actually performed (16.8 ± 11.9 months). Refractory course of the disease was identified as a predictor for a retrospectively desired earlier surgical approach (p = 0.014).

CONCLUSION

A substantial proportion of patients felt that they should have undergone surgery earlier than actually performed. It appears that timing of the decision to undergo surgery is suboptimal. This situation may be improved by earlier surgical consultation in the course of the disease.

Expression of phosphorylated estrogen receptor beta is an independent negative prognostic factor for pancreatic ductal adenocarcinoma

PURPOSE

The role of estrogen receptor beta (ER-β) expression in pancreatic ductal adenocarcinoma (PDAC) is largely unknown. Ligand-independent phosphorylation and activation of ER-β may play a relevant role in the IL-6/STAT3 signaling pathway and, as a result, in tumor progression. Here, we examined the effect of ER-β, phosphorylated ER-β (pER-β), STAT3, phosphorylated STAT3 (pSTAT3) and IL-6 expression on the overall and recurrence-free survival in a cohort of patients with resected PDAC.

METHODS

We identified 175 patients who underwent pancreatic resection for PDAC. Tissue microarrays were constructed from the archival tumor specimens. These were stained with specific antibodies for the above molecules. The expression of the markers was then correlated with clinicopathological parameters and survival analysis was performed.

RESULTS

High nuclear expression of ER-β was found in 61.7% and pER-β in 80.6% of the tumors. STAT3 was expressed in 54.3% of the tumor samples, pSTAT3 in 68% and IL-6 in 76.6%. The median overall survival for patients with low pER-β expression was 29 months, whereas for patients with high pER-β expression was 15.1 months (p = 0.016). Multivariate analysis revealed that pER-β expression was an independent factor correlating with shorter overall survival (hazard ratio 1.9; p = 0.013) and disease-free survival (hazard ratio 1.9; p = 0.029).

CONCLUSIONS

Expression of pER-β constitutes an independent prognostic marker for PDAC and is correlated with poor prognosis. These data may help in identifying novel drug targets in PDAC and patients who could benefit from additional therapeutic regimens, including selective estrogen receptor modulators.

Differential activation of afferent neuronal and inflammatory pathways during small bowel obstruction (SBO)

BACKGROUND

Small bowel obstruction (SBO) is a potentially life-threatening condition which may be caused by a variety of pathologies such as postoperative adhesions or malignant diseases. Little is known on alterations in gut physiology during SBO, although its comprehension is essential to improve treatment which may help to prevent subsequent organ failure prior to surgical resolution. We aimed to investigate afferent nerve sensitivity and intestinal inflammatory response during SBO to identify possible targets of treatment.

METHODS

C57Bl6 mice were anesthetized, and a midline laparotomy was performed. A small bowel loop was ligated 5 cm proximal to ileo-cecal valve to induce SBO. Control animals received a sham midline laparotomy. SBO animals and controls were sacrificed after 3, 9, or 24 h (each n = 6). A dilated segment of small intestine located 1.5 cm oral to the ligature was prepared for multi-unit mesenteric afferent nerve recordings in vitro. Histological assessment of leukocyte infiltration was performed by myeloperoxidase (MPO). Pro-inflammatory cytokine expression was quantified by RT-PCR. Data are mean ± SEM.

KEY RESULTS

Afferent firing to serosal 5-HT (500 μM) peaked at 3.9 ± 0.2 impulse/s 24 h after induction of SBO compared to 2.4 ± 0.1 impulse/s in sham controls (p < 0.05). Serosal bradykinin (0.5 μM) led to an increase in peak afferent firing of 5.3 ± 0.5 impulse/s in 24 h SBO animals compared to 3.5 ± 0.2 impulse/s in sham controls (p < 0.05). No differences in 5-HT and BK sensitivity were observed in 3 and 9 h SBO animals compared to controls. Continuous mechanical ramp distension of the intestinal loop was followed by a pressure-dependent rise in afferent nerve discharge that was reduced in 3 h SBO animals compared to sham controls (p < 0.05). MPO stains showed a rise in leukocyte infiltration of the intestine in SBO animals at 9 and 24 h (p < 0.05). Il-6 but not TNF-a gene expression was increased at 9 and 24 h in SBO animals compared to sham controls (p < 0.05).

CONCLUSIONS & INFERENCES

Afferent nerve sensitivity is increased 24 h after induction of SBO. SBO led to a delayed onset intestinal inflammatory response. Inflammatory mediators released during this inflammatory response may be responsible for a later increase in afferent sensitivity. Agents with anti-inflammatory action may, therefore, have a beneficial effect during SBO and may subsequently help to prevent possible organ dysfunction.

The CR-POSSUM Risk Calculator Predicts Failure of Enhanced Recovery after Colorectal Surgery

AIMS

To determine predictors of failed enhanced recovery after surgery (ERAS) in patients after elective colorectal surgery.

METHODS

A cohort of 55 patients undergoing elective colorectal surgery was monitored prospectively. Perioperative care was based on a previously established protocol for ERAS. Pre-, intra-, and postoperative parameters were analyzed to elicit predictors of ERAS failure. ERAS failure was defined as prolonged hospital stay (> 7 days). The risk calculator CR-POSSUM was evaluated for its clinical utility.

RESULTS

Body mass index (BMI) or the American Society of Anesthesiologists score (ASA) was not associated with ERAS failure on univariate analysis, but patients that failed ERAS were significantly older (64 y vs 54 y; p = 0.023). Prolonged length of stay (>7 days) was also associated with an open approach (p = 0.009), intraoperative nasogastric tube placement (p = 0.005), blood loss > 500 ml (p = 0.008), stoma formation (p = 0.006) and insertion of more than one intraabdominal drain during surgery (p = 0.005). Postoperative continuation of intravenous fluids (p = 0.027), reinsertion of urinary catheter (p = 0.045) and postoperative ileus (p = 0.020) were also strongly associated with delayed discharge on univariate analysis. After multivariate analysis the preoperative parameters CR-POSSUM score (p = 0.022), increasing BMI (p = 0.014) and preoperative albumin level (p = 0.031) were all independently associated with failure of ERAS.

CONCLUSIONS

A variety of perioperative factors contribute to failure of ERAS in routine practice. CR-POSSUM can help to identify patients at risk for possible failure of ERAS. This may help to optimize avoidable factors, or accommodate those patients likely to require a longer post-operative stay.

The CR-POSSUM Risk Calculator Predicts Failure of Enhanced Recovery after Colorectal Surgery

AIMS

To determine predictors of failed enhanced recovery after surgery (ERAS) in patients after elective colorectal surgery.

METHODS

A cohort of 55 patients undergoing elective colorectal surgery was monitored prospectively. Perioperative care was based on a previously established protocol for ERAS. Pre-, intra-, and postoperative parameters were analyzed to elicit predictors of ERAS failure. ERAS failure was defined as prolonged hospital stay (> 7 days). The risk calculator CR-POSSUM was evaluated for its clinical utility.

RESULTS

Body mass index (BMI) or the American Society of Anesthesiologists score (ASA) was not associated with ERAS failure on univariate analysis, but patients that failed ERAS were significantly older (64 y vs 54 y ; p = 0.023). Prolonged length of stay (> 7 days) was also associated with an open approach (p = 0.009), intraoperative nasogastric tube placement (p = 0.005), blood loss > 500 ml (p = 0.008), stoma formation (p = 0.006) and insertion of more than one intraabdominal drain during surgery (p = 0.005). Postoperative continuation of intravenous fluids (p = 0.027), reinsertion of urinary catheter (p = 0.045) and postoperative ileus (p = 0.020) were also strongly associated with delayed discharge on univariate analysis. After multivariate analysis the preoperative parameters CR-POSSUM score (p = 0.022), increasing BMI (p = 0.014) and preoperative albumin level (p = 0.031) were all independently associated with failure of ERAS.

CONCLUSIONS

A variety of perioperative factors contribute to failure of ERAS in routine practice. CR-POSSUM can help to identify patients at risk for possible failure of ERAS. This may help to optimize avoidable factors, or accommodate those patients likely to require a longer post-operative stay.

Antiproliferative and apoptotic effects of telmisartan in human colon cancer cells

Telmisartan is an angiotensin I (AT₁) receptor blocker used in the treatment of essential hypertension, with partial peroxisome proliferator-activated receptor γ (PPARγ) agonism. In prior studies, PPARγ activation led to apoptosis and cell cycle inhibition in various cancer cells. The aim of the present study was to investigate the potential antiproliferative and apoptotic effects of telmisartan by partially activating PPARγ. HT-29, SW-480 and SW-620 cells were incubated with telmisartan (0.2–5 μM) or the full agonist, pioglitazone (0.2–5.0 μM). The antiproliferative and apoptotic effects of telmisartan in the human colon cancer cells were significant at therapeutic serum concentrations, and telmisartan exhibited a potency at least equivalent to the full PPARγ agonist, pioglitazone. The antiproliferative and apoptotic effects of pioglitazone in the human colon cancer cells were not completely deregulated by PPARγ blockade with GW9662. In the telmisartan-treated cells, PPARγ blockade resulted in an increased antiproliferative and apoptotic effect. These effects are not entirely explained by PPARγ activation, however, possible hypotheses that require further experimental investigation are as follows: i) Ligand-independent PPARγ activation through the activation-function 1 domain; ii) a PPARγ-independent mechanism; or iii) independent antiproliferative and apoptotic effects through GW9662.

Loss of TRAIL-receptors is a recurrent feature in pancreatic cancer and determines the prognosis of patients with no nodal metastasis after surgery

INTRODUCTION

Agonistic antibodies targeting TRAIL-receptors 1 and 2 (TRAIL-R1 and TRAIL-R2) are being developed as a novel therapeutic approach in cancer therapy including pancreatic cancer. However, the cellular distribution of these receptors in primary pancreatic cancer samples has not been sufficiently investigated and no study has yet addressed the issue of their prognostic significance in this tumor entity.

AIMS AND METHODS

Applying tissue microarray (TMA) analysis, we performed an immunohistochemical assessment of TRAIL-receptors in surgical samples from 84 consecutive patients affected by pancreatic adenocarcinoma and in 26 additional selected specimens from patients with no lymph nodes metastasis at the time of surgery. The prognostic significance of membrane staining and staining intensity for TRAIL-receptors was evaluated.

RESULTS

The fraction of pancreatic cancer samples with positive membrane staining for TRAIL-R1 and TRAIL-R2 was lower than that of cells from surrounding non-tumor tissues (TRAIL-R1: p<0.001, TRAIL-R2: p = 0.006). In addition, subgroup analyses showed that loss of membrane staining for TRAIL-R2 was associated with poorer prognosis in patients without nodal metastases (multivariate Cox regression analysis, Hazard Ratio: 0.44 [95% confidence interval: 0.22-0.87]; p = 0.019). In contrast, analysis of decoy receptors TRAIL-R3 and -R4 in tumor samples showed an exclusively cytoplasmatic staining pattern and no prognostic relevance.

CONCLUSION

This is a first report on the prognostic significance of TRAIL-receptors expression in pancreatic cancer showing that TRAIL-R2 might represent a prognostic marker for patients with early stage disease. In addition, our data suggest that loss of membrane-bound TRAIL-receptors could represent a molecular mechanism for therapeutic failure upon administration of TRAIL-receptors-targeting antibodies in pancreatic cancer. This hypothesis should be evaluated in future clinical trials.

Heat shock protein 27 as a prognostic and predictive biomarker in pancreatic ductal adenocarcinoma

A role of heat shock protein 27 (HSP27) as a potential biomarker has been reported in various tumour entities, but comprehensive studies in pancreatic cancer are lacking. Applying tissue microarray (TMA) analysis, we correlated HSP27 protein expression status with clinicopathologic parameters in pancreatic ductal adenocarcinoma specimens from 86 patients. Complementary, we established HSP27 overexpression and RNA-interference models to assess the impact of HSP27 on chemo- and radiosensitivity directly in pancreatic cancer cells. In the TMA study, HSP27 expression was found in 49% of tumour samples. Applying univariate analyses, a significant correlation was found between HSP27 expression and survival. In the multivariate Cox-regression model, HSP27 expression emerged as an independent prognostic factor. HSP27 expression also correlated inversely with nuclear p53 accumulation, indicating either protein interactions between HSP27 and p53 or TP53 mutation-dependent HSP27-regulation in pancreatic cancer. In the sensitivity studies, HSP27 overexpression rendered HSP27 low-expressing PL5 pancreatic cancer cells more susceptible towards treatment with gemcitabine. Vice versa, HSP27 protein depletion in HSP27 high-expressing AsPC-1 cells caused increased gemcitabine resistance. Importantly, HSP27 expression was inducible in pancreatic cancer cell lines as well as primary cells. Taken together, our study suggests a role for HSP27 as a prognostic and predictive marker in pancreatic cancer. Assessment of HSP27 expression could thus facilitate the identification of specific patient subpopulations that might benefit from individualized treatment options. Additional studies need to clarify whether modulation of HSP27 expression could represent an attractive concept to support the incorporation of hyperthermia in clinical treatment protocols for pancreatic cancer.

Effect of raloxifene on human pancreatic adenocarcinoma growth in vitro and in vivo

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Background: The role of estrogen receptor (ER) signaling in pancreatic cancer is unknown. Recently, we demonstated that expression of the isoform ER beta correlates with an adverse prognosis in patients with pancreatic cancer. Here, we show that raloxifene, a specific estrogen receptor modulator (SERM), suppresses in vitro and in vivo tumor growth by interfering with ER beta signaling in human pancreatic adenocarcinoma.

Methods: The human pancreatic adenocarcinoma cell line L3.6pl was cultured and exposed to raloxifene in vitro, and cell proliferation was determined by the BrdU assay. To analyze the specificity of raloxifene induced effects, ER knockdown was performed using siRNA specific for ER alpha and ER beta. In an in vivo model of orthotopic tumor xenografts in nude mice, raloxifene was administered daily, and tumor growth was monitored. Expression of ER beta and the proliferation marker Ki-67 were determined by immunohistochemistry.

Results: Raloxifene treatment resulted in a potent, dose dependent reduction of proliferation in vitro over a nanomolar dose range. This effect was completely reversed by siRNA knockdown of ER beta, but not ER alpha, indicating an ER isotype specific signaling. In vivo, orthotopic tumor growth, as well as lymph node and liver metastases, was significantly suppressed in raloxifene treated mice. Analogous to the in vitro data, Ki-67 expression in vivo was significantly reduced in raloxifene treated mice, while ER beta expression was not changed in vivo.

Conclusions: Inhibition of ER beta signaling by raloxifene results in a potent reduction of human pancreatic adenocarcinoma growth in vitro and in vivo. Treatment with SERMs may be an attractive therapeutic option in subjects expressing the ER beta isotype.

No significant financial relationships to disclose.

Src tyrosine kinase inhibition suppresses lymphangiogenesis in vitro and in vivo

PURPOSE

The close association of lymphatic and blood vessels and their coordinated development in vivo suggest that there are parallel mechanisms regulating hemangiogenesis and lymphangiogenesis. Here, we hypothesize that inhibition of the Src tyrosine kinase, apart from anti-hemangiogenic effects, results in a suppression of lymphangiogenesis.

EXPERIMENTAL DESIGN

The ability of the Src kinase inhibitor PP2 to block Src in isolated lymphatic endothelial cells (LECs) was analyzed by Western Blot. The effects of PP2 on LEC proliferation, migration, and sprouting were assessed by MTT, Boyden chamber, and spheroid assays, respectively. The level of VEGF-C secreted by L3.6pl pancreatic carcinoma cells was measured by ELISA. For in vivo assessment of lymphangiogenesis, Src kinase inhibitor AZM475271 was used in mouse corneal micropocket and lymphangioma models.

RESULTS

VEGF-C stimulation of isolated LECs led to an increased phosphorylation of Src kinase that was abrogated by PP2. Treatment with PP2 inhibited spheroid sprouting of LECs at even lower concentrations than suggested by the proliferation assay. Src inhibition significantly reduced the level of VEGF-C in L3.6pl supernatant. Treatment with PP2 also resulted in a significant reduction in the migratory activity of LECs. In vivo, Src inhibition reduced de novo formation of lymphangiomas and corneal neovascularization.

CONCLUSIONS

Inhibition of Src kinase shows strong anti-lymphangiogenic activity in vitro and in vivo. Together with anti-angiogenic effects mediated by Src inhibition, this strategy may be attractive in the treatment of lymphatic and hematogeneous metastasis of cancer.

Abstract 1330: Low dose irradiation reverts chemoresistance towards fluorouracil in human pancreatic adenocarcinoma cells by upregulation of thymidine phosphorylase

Background: Resistance towards cytotoxic drugs and ionizing radiation (IR) accounts for poor therapy response in pancreatic cancer. The radiosensitizing effects of fluorouracil (FU) are well characterized, however, it is not known whether IR itself exerts sensitizing effects towards cytotoxic chemotherapy. Here, we hypothesize that IR induced upregulation of thymidine phosphorylase (TP) results in a reversal of resistance towards FU.

Methods: An FU resistant variant of the human pancreatic adenocarcinoma cell line AsPC-1 was developed by long term in vitro FU exposure. Proliferation of AsPC-1 and AsPC-1FUres cells was determined by an MTT proliferation assay after previous low dose (0.05 Gy) exposure of IR. To antagonize a possible effect mediated by TP upregulation, anti-TP siRNA was added in the same setting. TP expression in AsPC-1 cells before and after IR was determined by Western blotting.

Results: FU resistant AsPC-1 cells showed a 7.5-fold increase of the IC50 after FU exposure, compared to non-resistant cells. When challenging both cell lines with FU after low dose IR, no significant difference of proliferation was observed in AsPC-1 cells and their FU resistant variant, suggesting a reversal of chemoresistance by IR. This chemosensitizing effect was abrogated when blocking TP by anti-TP siRNA before IR. In cell lysates harvested from AsPC-1 cells, an increase of TP expression was seen after exposure of low dose IR (0.05 Gy) as well as high dose IR (2.0 Gy).

Conclusion: Our results suggest a TP mediated reversal of chemoresistance towards FU that is triggered by low dose IR in vitro. These results have to be confirmed in an in vivo model. In conclusion, induction of TP expression by low dose irradiation may be an interesting concept to overcome chemotherapy resistance in pancreatic cancer.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1330.

Abstract 3911: Dysegulation of Sox9-dependent gene expression leads to enhancement of angiogenesis and metastases in pancreatic cancer

Background: The understanding of invasion, angiogenesis and metastasis is essential for the development of new targeted molecular therapy against pancreatic cancer. The aim of this study is to analyse the regulation of differentially expressed genes in highly proangiogenic and prometastatic compared to low metastatic and low angiogenic pancreatic cancer cells

Materials and methods: The transcriptome of the low metastatic pancreatic cancer cell line and its highly angiogenic and metastatic derivate L3.6pl have been compared under the normoxic and hypoxic conditions using Affymetrix HGU133plus 2.0 arrays. The hierarchic cluster analysis has been performed using SOTA algorithm. Promoters of the differentially expressed genes have been analysed using oPOSSUM 2 program. Affymetrix data have been validated via qRT-PCR and via ELISA. Chromosomal DNA containing promoters of the relevant genes has been amplified via PCR and sequenced.

Results: The Affymetrix analysis revealed clusters of differentially regulated genes with regard to the cell line and the oxygen level. While VEGF expression was upregulated in FG cells under hypoxic condition, it was constitutively upregulated already under normoxic conditions in L3.6pl and no further stimulation was observed under hypoxic conditions. This regulation pattern was similar in a cluster of genes that share a promoter sequence coding for a binding site for the transcription factor Sox9. Sox9 itself shows a similar regulation, leading to the assumption that expression changes of Sox9 are involved in the different hypoxic gene expressions. Promoter analysis of Sox9 in FG and L3.6pl cells showed mutations in the promoter region in L3.6pl, while the VEGF promoter was unchanged. Further analysis has shown that this mutation is not relevant for biological function. Refined analysis revealed differential Sox9 promoter methylation as reason for observed phenomenon.

Conclusions: Proangiogenic genes such as VEGF are upregulated in the more aggressive cell line L3.6pl, compared to FG. We identified a gene cluster that is constitutively upregulated in L3.6pl, independent of hypoxia. These genes are controlled by the transcription factor Sox9. A Sox9 promoter differential methylation may be the reason for the escape from hypoxic regulation in L3.6pl cells and thus may contribute to the higher angiogenic and metastatic potential. Taken together, Sox9 may be an interesting new diagnostic and therapeutic target in pancreatic cancer progression.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3911.

Abstract 3901: Sox9-associated overexpression of IFIT3 leads to pancreatic cancer progression by activation of “pseudoinflammatory” pathways

The understanding of invasion, angiogenesis and metastasis is essential for the development of new molecular therapy against cancer. Inflammation plays important role in tumour initiation and progression. Here we report the role of the transcription factor Sox9 for regulation of IFIT3 an inflammation-related and tumour-promoting protein in pancreatic cancer. For in vivo and in vitro experiments we utilized the following human pancreatic cancer cell lines: low metastatic FG, high metastatic L3.6pl, and the stable transfected cell line FG-IFIT3. To demonstrate effects on primary tumor growth and metastases in vivo we orthotopically injected the different cell lines in the pancreas of nude mice. To evaluate the VEGF depending angiogenic capacity of the different cell lines ELISA technology was used. By One STrEP technology we were able to identify IFIT3-binding partners. Chromosomal immunoprecipitation (ChIP) using anti-Sox9 antibody, followed by PCR amplifying the IFIT3-promoter was used to identify the interaction of the IFIT3 promoter with the transcription factor Sox9. To investigate Sox9-depending expression of IFIT3 (protein and RNA) we used stable transfected L3.6pl-Sox9-shRNA cells under control of the Tet-CMV promoter in presence or absence of tetracycline, respectively. Analysis of differential gene expression by gene array technology demonstrated that the IFIT3 gene is up-regulated in L3.6pl cells as compared to FG cells. Results of animal experiment and in vitro experiments clearly demonstrated tumor-promoting, pro-metastatic and pro-angiogenic features of IFIT3. RT-PCR has revealed that both treatment with IFna as well as NFkB led to up-regulation of IFIT3-RNA expression. One STrEP experiments identified JNK and STAT1 as binding partners of IFIT3. ChIP has demonstrated binding of the transcription factor Sox9 to the IFIT3 promoter. RT-PCR and immunoblot data demonstrated constitutive up-regulation of Sox9 expression in L3.6pl cells. By Western blotting and RT-PCR we could show that diminishing of Sox9 expression in stable transfected L3.6pl Sox9-shRNA cells leads to a significant down-regulation of IFIT3-epression on the RNA and protein level.

The inflammation associated protein IFIT3 is up-regulated in metastatic L3.6pl human pancreatic cancer cells and is in part responsible for the aggressive primary pancreatic tumor growth in vivo. This gene is up-regulated by IFna and NFkB. Interestingly Sox9 binds to the IFIT3P and activates its expression. Since in L3.6pl cells Sox9 is constitutively over-expressed, IFIT3 is up-regulated independent on the presence of the cytokine IFna. Therefore, the pro-inflammatory IFna-signaling pathway is activated even without actual inflammation in absence pro-inflammatory cytokine. The activation of such a “pseudo-inflammatory pathway” seems to be in part responsible for pancreatic cancer progression.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3901.

EFEMP1 binds the EGF receptor and activates MAPK and Akt pathways in pancreatic carcinoma cells

The EGF-related protein EFEMP1 (EGF-containing fibulin-like extracellular matrix protein 1) has been shown to promote tumor growth in human adenocarcinoma. To understand the mechanism of this action, the signal transduction activated upon treatment with this protein has been investigated. We show that EFEMP1 binds EGF receptor (EGFR) in a competitive manner relative to epidermal growth factor (EGF), implicating that EFEMP1 and EGF share the same or adjacent binding sites on the EGFR. Treatment of pancreatic carcinoma cells with purified EFEMP1 activates autophosphorylation of EGFR at the positions Tyr-992 and Tyr-1068, but not at the position Tyr-1048. This signal is further transduced to phosphorylation of Akt at position Thr-308 and p44/p42 MAPK (mitogen-activated protein kinase) at positions Thr-202 and Tyr-204. These downstream phosphorylation events can be inhibited by treatment with the EGFR kinase inhibitor PD 153035. The observed signal transduction upon treatment with EFEMP1 can contribute to the enhancement of tumor growth shown in pancreatic carcinoma cells overexpressing EFEMP1.

Determinants of morbidity and survival after elective non-curative resection of stage IV colon and rectal cancer

PURPOSE

The benefit of elective primary tumor resection for non-curable stage IV colorectal cancer (CRC) remains largely undefined. We wanted to identify risk factors for postoperative complications and short survival.

METHODS

Using a prospective database, we analyzed potential risk factors in 233 patients, who were electively operated for non-curable stage IV CRC between 1996 and 2002. Patients with recurrent tumors, resectable metastases, emergency operations, and non-resective surgery were excluded. Risk factors for increased postoperative morbidity and limited postoperative survival were identified by multivariate analyses.

RESULTS

Patients with colon cancer (CC = 156) and rectal cancer (RC = 77) were comparable with regard to age, sex, comorbidity, American Society of Anesthesiologists score, carcinoembryonic antigen levels, hepatic spread, tumor grade, resection margins, 30-day mortality (CC 5.1%, RC 3.9%) and postoperative chemotherapy. pT4 tumors, carcinomatosis, and non-anatomical resections were more common in colon cancer patients, whereas enterostomies (CC 1.3%, RC 67.5%, p < 0.0001), anastomotic leaks (CC 7.7%, RC 24.2%, p = 0.002), and total surgical complications (CC 19.9%, RC 40.3%, p = 0.001) were more frequent after rectal surgery. Independent determinants of an increased postoperative morbidity were primary rectal cancer, hepatic tumor load >50%, and comorbidity >1 organ. Prognostic factors for limited postoperative survival were hepatic tumor load >50%, pT4 tumors, lymphatic spread, R1-2 resection, and lack of chemotherapy.

CONCLUSIONS

Palliative resection is associated with a particularly unfavorable outcome in rectal cancer patients presenting with a locally advanced tumor (pT4, expected R2 resection) or an extensive comorbidity, and in all CRC patients who show a hepatic tumor load >50%. For such patients, surgery might be contraindicated unless the tumor is immediately life-threatening.

Blumgart anastomosis for pancreaticojejunostomy minimizes severe complications after pancreatic head resection

BACKGROUND

Leakage from the pancreaticojejunostomy is the major cause of septic complications after partial pancreaticoduodenectomy. This study evaluated a new transpancreatic U-suture technique (Blumgart anastomosis, BA), which aims to avoid shear forces during knot-tying.

METHODS

Using a before-after study design, BA was compared with a modified Cattell-Warren anastomosis (CWA). Two patient cohorts (CWA, 90; BA, 92), which were similar with respect to primary diagnosis, age, sex and American Society of Anesthesiologists score, were compared retrospectively. Dependent variables were surgical and overall morbidity and mortality after partial pancreaticoduodenectomy.

RESULTS

Duration of operation (354 versus 328 min for CWA versus BA; P = 0.002), pancreatic leakage rate (13 versus 4 per cent; P = 0.032), postoperative haemorrhage (11 versus 3 per cent; P = 0.040), total surgical complications (31 versus 15 per cent; P = 0.011), general complications (36 versus 17 per cent; P = 0.005) and length of intensive care unit stay (median 5.4 versus 2.8 days; P = 0.015) were significantly reduced after BA. These effects were not related merely to an improvement over time.

CONCLUSION

BA appears to be a fast, simple and safe technique for pancreaticojejunostomy. It might reduce leakage rates and surgical complications after partial pancreaticoduodenectomy.

Pancreatic cancer stem cells: new understanding of tumorigenesis, clinical implications

PURPOSE

Since the discovery of cancer cells with stem-like characteristics in hematopoietic malignancies and, more recently, in solid tumors, enormous attention has been paid to the stem-cell nature of pancreatic cancer. Among the most important properties of cancer stem cells their high capacity for tumorigenicity as well as their ability to metastasize is under special research interest today.

METHODS

Here, we give a brief overview of main components used to confirm the stem-cell-like behavior of putative cancer stem cells and discuss markers and methods for identifying them in pancreatic cancer. Finally, the review provides some new suggestions as to how specifically target these cells and improve current therapy regimens.

RESULTS

The cancer stem-cell hypothesis is a fundamentally different model of carcinogenesis composed of two separate but dependent on each other characteristics of stem cells--aberrant activation of their tightly regulated processes of self-renewal and differentiation and their resistance towards chemo- and radiotherapy. The cancer stem cells may further be identified based on their expression of cell surface markers or their functional characteristics. The concept of molecular targeting of such highly tumorigenic cancer cells aimed to sensitize tumors toward conventional therapies and effectively abrogate tumor growth and metastasis.

CONCLUSIONS

The presence of cancer stem cells in pancreatic tumors has prognostic relevance and influences therapeutic response. Evidence suggests that metastatic potential may be conferred to these highly tumorigenic cells as well. A better understanding of the biological behavior of these cells may further improve therapeutic approaches and outcomes in patients with this devastating disease.

Cancer stem cells: how can we target them?

One of the most exciting concepts being explored in cancer research today is the idea of cancer stem cells. Evidence for the existence of such cells was first proposed for haematological malignancies and, more recently, for solid tumors, including breast, brain, colon and pancreatic cancer. The cancer stem cell hypothesis states that a minority of transformed stem cells, or progenitors with acquired self-renewal properties, are the source of tumor cell renewal and thereby determine the behaviour of tumors, including proliferation, spreading and response to chemo- and radiotherapy. Indeed, just as somatic stem cells may be resistant to the induction of apoptosis by cytotoxic agents and radiation therapy, cancer stem cells may display increased resistance to these agents as compared with the more differentiated cells that comprise the mass of tumors. More specifically, the reactivation of varied developmental signalling cascades (epidermal growth factor (EGF)/EGFR, stem cell factor (SCF)/KIT, sonic hedgehog, Notch, and/or Wnt/beta-catenin) combined with the increased DNA repair mechanisms and ABC transporter-mediated drug efflux in cancer stem cells may be responsible for their resistance to conventional therapies. Furthermore, changes in the local microenvironment of cancer stem cells may also influence their behaviour. Thus, the molecular targeting of such highly tumorigenic cancer cells must be considered for improving the efficacy of the current anti-cancer strategies with the aim to sensitize tumors toward conventional therapies and effectively abrogate tumorigenesis. This review provides a summary of some developments in the field of cancer stem cell targeting and highlights aspects where it could be of help in the drug discovery process.

EFEMP1 expression promotes in vivo tumor growth in human pancreatic adenocarcinoma

The progression of pancreatic cancer is dependent on local tumor growth, angiogenesis, and metastasis. EFEMP1, a recently discovered member of the fibulin family, was characterized with regard to these key elements of pancreatic cancer progression. Differential gene expression was assessed by mRNA microarray hybridization in FG human pancreatic adenocarcinoma cells and L3.6pl cells, a highly metastatic variant of FG. In vivo orthotopic tumor growth of EFEMP1-transfected FG cells was examined in nude mice. To assess the angiogenic properties of EFEMP1, vascular endothelial growth factor (VEGF) production of tumor cells, endothelial cell proliferation and migration, and tumor microvessel density were analyzed in response to EFEMP1. Further, tumor cell apoptosis, cell cycle progression, and resistance to cytotoxic agents were quantitated by propidium iodide staining and flow cytometry. In microarray hybridization, EFEMP1 was shown to be significantly up-regulated in L3.6pl cells compared with FG cells. Concordantly, EFEMP1 transfection of FG cells stimulated orthotopic and metastatic tumor growth in vivo. EFEMP1 expression resulted in a stimulation of VEGF production by tumor cells and an increased number of CD31-positive microvessels. Endothelial cell proliferation and migration were not altered by EFEMP1, indicating an indirect angiogenic effect. Further, EFEMP1 expression decreased apoptosis and promoted cell cycle progression in response to serum starvation or exposure to gemcitabine, 5-fluorouracil, and irinotecan. EFEMP1 has protumorigenic effects on pancreatic cancer in vivo and in vitro mediated by VEGF-driven angiogenesis and antiapoptotic mechanisms. Hence, EFEMP1 is a promising candidate for assessing prognosis and individualizing therapy in a clinical tumor setting.

Matuzumab short-term therapy in experimental pancreatic cancer: prolonged antitumor activity in combination with gemcitabine

PURPOSE

The epidermal growth factor receptor ErbB-1 is commonly expressed in pancreatic cancer and ErbB-1 targeting has shown promising results. We wanted to evaluate matuzumab (EMD72000), a fully humanized ErbB-1-specific monoclonal antibody in combination with gemcitabine in experimental pancreatic cancer.

EXPERIMENTAL DESIGN

Using the human pancreatic cancer cell line L3.6pl, we investigated matuzumab in vitro and in vivo. ErbB-1 phosphorylation and downstream pathway activation were evaluated by Western blot. Proliferation and migration assays and fluorescence-activated cell sorting analysis were done. For in vivo studies, we used an orthotopic nude mice model in which 40 mg/kg of matuzumab+/-100 mg/kg of gemcitabine were administered twice weekly. Different treatment durations (7, 14, 21, and 25 days) and varying time points of treatment initiation (days 8, 15, 22, and 29) were evaluated. Ki67, CD31, and phosphorylated p44/42 mitogen-activated protein kinase (MAPK) immunohistochemistry were done.

RESULTS

ErbB-1 phosphorylation and downstream MAPK and AKT signaling were significantly reduced by matuzumab. Matuzumab significantly inhibited proliferation and migration in vitro, and induced tumor cell apoptosis in a dose-dependant manner. Matuzumab therapy significantly lowered tumor volume in vivo, reduced lymph node and liver metastases, and decreased microvessel density and tumor cell proliferation. These effects were significantly enhanced when gemcitabine was added. A significant and prolonged antitumor activity was even evident with short-term therapy (7 days) and with a late onset of therapy (day 22 after tumor cell injection).

CONCLUSIONS

Matuzumab is an effective agent with long-lasting antiproliferative, proapoptotic, antiangiogenic, and antimetastatic activity in human pancreatic cancer models. These effects might be potentiated by gemcitabine.

The challenge of pancreatic anastomosis

BACKGROUND AND AIMS

Significant progress in surgical technique and perioperative management has substantially reduced the mortality rate of pancreatic surgery. However, morbidity remains considerably high, even in expert hands and leakage from the pancreatic stump still accounts for the majority of surgical complications after pancreatic head resection. For that reason, management of the pancreatic remnant after partial pancreatoduodenectomy remains a challenge. This review will focus on technique, pitfalls, and complication management of pancreaticoenteric anastomoses.

MATERIALS AND METHODS

A medline search for surgical guidelines, prospective randomized controlled trials, systematic metaanalysis, and clinical reports was performed with regard to surgical technique and complication management of pancreatic anastomoses.

RESULTS

Pancreaticojejunostomy appears to be most widely performed, but pancreaticogastrostomy is a reasonable alternative. Postoperative treatment with octreotide can be recommended only for patients with soft pancreatic tissue, and neither stents of the pancreatic duct nor drainages have proven to effectively reduce anastomotic complications. Gastroparesis remains the most common complication after pancreatic surgery and should be treated conservatively. However, it may be a symptom of other local complications, such as anastomotic leakage, pancreatic fistula or abscess. All septic complications may finally result in late postoperative hemorrhage, which requires immediate diagnostic workup and therapy. Today, interventional radiology has emerged as a standard tool in the management of local septic complications and bleeding. Therefore, relaparotomy has become less frequent and salvage pancreatectomy is now a rare procedure in case of local complications.

CONCLUSION

The surgeon's experience with one or the other technique of pancreatic anastomosis appears to be more important than the technique itself.

Role of mTOR in solid tumor systems: a therapeutical target against primary tumor growth, metastases, and angiogenesis

The mammalian target of rapamycin (mTOR) is a controller of cell growth with multiple effects on cancer development and progression. Being closely linked to key oncogenic pathways that regulate tumor cell growth and cell cycle progression, mTOR integrates the cellular response to mitogenic and growth stimuli. Rapamycin and its analogs temsirolimus and everolimus are specific inhibitors of mTOR that exert suppressive effects on proliferation, invasion, and metastasis and induce apoptosis of tumor cells. Apart from the direct effects of mTOR inhibitors on tumor cells, rapamycin and its analogs have potent antiangiogenic properties related to the suppression of vascular endothelial growth factor signal transduction. While the use of mTOR inhibitors as a monotherapy seems to be insufficient to effectively control tumor progression in most tumor entities, combination with tyrosine kinase inhibitors or cytotoxic agents might potentiate the antitumoral effects of mTOR inhibition. In a clinical setting, mTOR inhibitors show an acceptable safety profile over a wide dose range. Currently, mTOR inhibitors are tested in multiple trials in combination with other agents in various cancer entities in intermittent schedules to avoid immunosuppression. However, lacking adequate surrogate and response parameters, the most effective biological dosing schedules remain to be defined. Considering these apparent limitations, the full clinical potential of this promising class of drugs is at risk to be missed by applying them inadequately.

Rapamycin induces tumor-specific thrombosis via tissue factor in the presence of VEGF

Therapeutic strategies that target and disrupt the already-formed vessel networks of growing tumors are actively pursued. The goal of these approaches is to induce a rapid shutdown of the vascular function of the tumor so that blood flow is arrested and tumor cell death occurs. Here we show that the mammalian target of rapamycin (mTOR) inhibitor rapamycin, when administered to tumor-bearing mice, selectively induced extensive local microthrombosis of the tumor microvasculature. Importantly, rapamycin administration had no detectable effect on the peritumoral or normal tissue. Intravital microscopy analysis of tumors implanted into skinfold chambers revealed that rapamycin led to a specific shutdown of initially patent tumor vessels. In human umbilical vein endothelial cells vascular endothelial growth factor (VEGF)–induced tissue factor expression was strongly enhanced by rapamycin. We further show by Western blot analysis that rapamycin interferes with a negative feedback mechanism controlling this pathologic VEGF-mediated tissue factor expression. This thrombogenic alteration of the endothelial cells was confirmed in a one-step coagulation assay. The circumstance that VEGF is up-regulated in most tumors may explain the remarkable selectivity of tumor vessel thrombosis under rapamycin therapy. Taken together, these data suggest that rapamycin, besides its known antiangiogenic properties, has a strong tumor-specific, antivascular effect in tumors.