Pre-treatment inflamed tumor immune microenvironment is associated with FOLFIRINOX response in pancreatic cancer

Introduction

Pancreatic adenocarcinoma (PDAC) is an aggressive tumor with limited response to both chemotherapy and immunotherapy. Pre-treatment tumor features within the tumor immune microenvironment (TiME) may influence treatment response. We hypothesized that the pre-treatment TiME composition differs between metastatic and primary lesions and would be associated with response to modified FOLFIRINOX (mFFX) or gemcitabine-based (Gem-based) therapy.

Methods

Using RNAseq data from a cohort of treatment-naïve, advanced PDAC patients in the COMPASS trial, differential gene expression analysis of key immunomodulatory genes in were analyzed based on multiple parameters including tumor site, response to mFFX, and response to Gem-based treatment. The relative proportions of immune cell infiltration were defined using CIBERSORTx and Dirichlet regression.

Results

145 samples were included in the analysis; 83 received mFFX, 62 received Gem-based therapy. Metastatic liver samples had both increased macrophage (1.2 times more, p < 0.05) and increased eosinophil infiltration (1.4 times more, p < 0.05) compared to primary lesion samples. Further analysis of the specific macrophage phenotypes revealed an increased M2 macrophage fraction in the liver samples. The pre-treatment CD8 T-cell, dendritic cell, and neutrophil infiltration of metastatic samples were associated with therapy response to mFFX (p < 0.05), while mast cell infiltration was associated with response to Gem-based therapy (p < 0.05). Multiple immunoinhibitory genes such as ADORA2A, CSF1R, KDR/VEGFR2, LAG3, PDCD1LG2, and TGFB1 and immunostimulatory genes including C10orf54, CXCL12, and TNFSF14/LIGHT were significantly associated with worse survival in patients who received mFFX (p = 0.01). There were no immunomodulatory genes associated with survival in the Gem-based cohort.

Discussion

Our evidence implies that essential differences in the PDAC TiME exist between primary and metastatic tumors and an inflamed pretreatment TiME is associated with mFFX response. Defining components of the PDAC TiME that influence therapy response will provide opportunities for targeted therapeutic strategies that may need to be accounted for in designing personalized therapy to improve outcomes.

Interobserver Variability and Challenges in Intraoperative Frozen Section Evaluation of Pancreatic Margins in Pancreatectomy Specimens

OBJECTIVE

Frozen-section evaluation of the pancreatic margin is challenging. We aimed to determine interobserver variability among gastrointestinal pathologists for the assessment of frozen sections of pancreatic margins with marked chronic pancreatitis and to determine the challenging histological features in discrepant cases.

METHODS

We identified 45 patients who underwent pancreas resection for pancreatic ductal adenocarcinoma and showed marked chronic pancreatitis at pancreatic margin. Deidentified first levels of frozen-sections of the pancreatic margins from all cases were independently reviewed by 5 experienced gastrointestinal pathologists for the presence of carcinoma and/or high-grade dysplasia.

RESULTS

Interobserver agreement among pathologists was calculated as kappa coefficients ([Formula: see text]). A consensus diagnosis for discordant cases was obtained after group review and discussion. Interobserver agreement for adenocarcinoma diagnosis was 87%, and there was "substantial agreement" (Fleiss [Formula: see text]=0.78, P<0.01) and "almost perfect agreement" (Brennan-Prediger [Formula: see text]=0.86, P<0.01). Using the final diagnosis based on frozen and permanent sections as the gold standard and the concordant read of at least 3 of 5 pathologists for comparison, the diagnosis of adenocarcinoma was made in frozen-sections of pancreas margins, with accuracy 98%, sensitivity 83%, specificity 100%, negative predictive value 97%, positive predictive value 100%, false negative rate 9%, and false positive rate 0%.

CONCLUSIONS

We showed excellent interobserver agreement among gastrointestinal pathologists for diagnosis of adenocarcinoma on frozen sections of pancreatic margins with marked chronic pancreatitis. Missed adenocarcinoma at the margin was mainly caused by freezing or cautery artifacts or by overlooking a tiny focus of perineural invasion in a background of marked chronic pancreatitis. The evaluation of deeper levels led to perfect agreement.

CD73-Dependent Adenosine Signaling through Adora2b Drives Immunosuppression in Ductal Pancreatic Cancer

The microenvironment that surrounds pancreatic ductal adenocarcinoma (PDAC) is profoundly desmoplastic and immunosuppressive. Understanding triggers of immunosuppression during the process of pancreatic tumorigenesis would aid in establishing targets for effective prevention and therapy. Here, we interrogated differential molecular mechanisms dependent on cell of origin and subtype that promote immunosuppression during PDAC initiation and in established tumors. Transcriptomic analysis of cell-of-origin-dependent epithelial gene signatures revealed that Nt5e/CD73, a cell-surface enzyme required for extracellular adenosine generation, is one of the top 10% of genes overexpressed in murine tumors arising from the ductal pancreatic epithelium as opposed to those rising from acinar cells. These findings were confirmed by IHC and high-performance liquid chromatography. Analysis in human PDAC subtypes indicated that high Nt5e in murine ductal PDAC models overlaps with high NT5E in human PDAC squamous and basal subtypes, considered to have the highest immunosuppression and worst prognosis. Multiplex immunofluorescent analysis showed that activated CD8+ T cells in the PDAC tumor microenvironment express high levels of CD73, indicating an opportunity for immunotherapeutic targeting. Delivery of CD73 small-molecule inhibitors through various delivery routes reduced tumor development and growth in genetically engineered and syngeneic mouse models. In addition, the adenosine receptor Adora2b was a determinant of adenosine-mediated immunosuppression in PDAC. These findings highlight a molecular trigger of the immunosuppressive PDAC microenvironment elevated in the ductal cell of origin, linking biology with subtype classification, critical components for PDAC immunoprevention and personalized approaches for immunotherapeutic intervention.

SIGNIFICANCE

Ductal-derived pancreatic tumors have elevated epithelial and CD8+GZM+ T-cell CD73 expression that confers sensitivity to small-molecule inhibition of CD73 or Adora2b to promote CD8+ T-cell-mediated tumor regression. See related commentary by DelGiorno, p. 977.

Pretreatment Health-Related Quality-of-Life Status and Survival in Pancreatobiliary Surgical Patients

BACKGROUND

Pancreatobiliary (PB) disorders, especially cancer, negatively affect patients' health-related quality of life (HRQoL). However, the influence of baseline, preintervention HRQoL on perioperative and oncologic outcomes has not been well defined. We hypothesized that low baseline HRQoL is associated with worse perioperative and long-term survival outcomes for PB surgical patients.

STUDY DESIGN

Pretreatment Functional Assessment of Cancer Therapy - Hepatobiliary Survey results and clinical data from PB patients (2008 to 2016) from a single center's prospective database were analyzed. Survey responses were aggregated into composite scores and divided into quintiles. Patients in the highest quintile of HRQoL were compared to patients in the bottom four quintiles combined. Overall survival (OS) and disease-free survival (DFS) were analyzed using the Kaplan-Meier method. Logistic and Cox regressions were used to determine associations between quintiles of HRQoL scores and 30-day complications and long-term survival, respectively.

RESULTS

Of 162 patients evaluated, 99 had malignancy, and 63 had benign disease. Median follow-up was 31 months. Baseline HRQoL scores were similar for benign and malignant disease (p = 0.42) and were not associated with the development of any (p = 0.08) or major complications (p = 0.64). Patients with highest quintile HRQoL scores had improved 3-year OS (84.6 vs 61.7%, p = 0.03) compared to patients in the lowest four quintiles of HRQoL. Among cancer patients only, those with the highest quintile scores had improved 3-year OS (81.6 vs 47.4%, p = 0.02). On multivariable analysis, highest quintile HRQoL scores were associated with longer OS and DFS for patients with malignancy.

CONCLUSIONS

Pretreatment HRQoL was associated with both OS and DFS among PB patients and might have prognostic utility. Future studies are necessary to determine whether patients with poorer HRQoL may benefit from targeted psychosocial interventions.

MUC1 Expressions and Its Prognostic Values in US Gastric Cancer Patients

This study aims to evaluate the prognostic value of MUC expression in US GC patients. A total of 70 tumor specimens were collected from GC patients who underwent surgery or endoscopic resection between 2013 and 2019 at a tertiary referral center in the US. MUC expression status including MUC1, MUC2, MUC5AC, and MUC6 was evaluated by immunohistochemical staining. The positive rates of MUC1, MUC2, MUC5AC, and MUC6 were 71.4%, 78.6%, 74.3%, and 33.3%, respectively. Patients with positive MUC1 expression had a significantly higher rate of aggressive pathologic features including diffuse-type cancer (42.0% vs. 0%; p < 0.001), advanced GC (80.0% vs. 30.0%, p < 0.001), lymph node metastasis (62.0% vs. 20.0%; p = 0.001), and distant metastasis (32.0% vs. 5.0%; p = 0.017) compared with those with negative MUC1 expression. However, the differences in the pathologic features were not observed according to MUC2, MUC5AC, and MUC6 expression status. In early gastric cancer (EGC), patients with a high level of MUC1 expression showed a higher rate of lymphovascular invasion (71.4% vs. 21.4%; p = 0.026) and EGC meeting non-curative resection (85.7% vs. 42.9%; p = 0.061) than those with negative MUC1. In US GC patients, MUC1 expression is associated with aggressive pathological features, and might be a useful prognostic marker.

Factors associated with inability to return to intended oncologic treatment in pancreatic cancer

BACKGROUND

Return to Intended Oncologic Treatment (RIOT) has been proposed as a quality metric in the care of cancer patients. We sought to define factors associated with inability to RIOT in Pancreatic Ductal Adenocarcinoma (PDAC) patients.

METHODS

The NCDB was queried for patients who underwent pancreaticoduodenectomy for pathologic stage IB, IIA, or IIB PDAC from 2010 to 2016. Multivariable binary logistic regression models identified factors associated with failure to RIOT, and Kaplan-Meier survival analysis and Cox multivariable regression models demonstrated the impact of failure to RIOT on survival.

RESULTS

Increasing age (p < .001), Hispanic race (p = .002), pathological stage IB (p = .004) and IIA (p = .001) as compared to IIB, increasing hospital stay (p < .001), and open surgical approach (p = .024) were associated with increased risk of inability to RIOT. Male sex (p < .001), Charlson-Deyo scores of 0 (p < .001) and 1 (p = .001) as compared to >2, negative surgical margins (p = .048), receiving care at academic institutions (p = .001), and increasing institutional case volume (p = .001) were associated with improved odds of RIOT.

CONCLUSIONS

Patient features can impact RIOT and should be considered when designing multi-modality treatment strategies.

Hemoglobin A1c Is a Predictor of New Insulin Dependence After Partial Pancreatectomy: A Multi-Institutional Analysis

BACKGROUND

Pancreatic diseases have long been associated with impaired glucose control. This study sought to identify the incidence of new insulin-dependent diabetes mellitus (IDDM) after pancreatectomy and the predictive accuracy of hemoglobin A1c (HbA1c) or blood glucose.

METHODS

Patients who underwent partial pancreatectomy and had preoperative HbA1c available at two academic institutions were assessed for new IDDM on discharge in relation to complication rates and survival.

RESULTS

Of the 267 patients analyzed, 67% had abnormal HbA1c levels prior to surgery (mean 6.8%, glucose 135 mg/dL). Two hundred eight (77.9%) were not insulin-dependent prior to surgery, and 35 (16.8%) developed new IDDM after resection. On multivariable regression, increasing HbA1c and preoperative glucose were the only significant predictors for new IDDM. Optimal predictive cutoffs (HbA1c of 6.25% and glucose of 121 mg/dL) were determined in a discovery group (n = 143) and confirmed in a validation group (n = 124) with a diagnostic sensitivity of 72.7% and specificity of 84.8%. Patients with new IDDM after resection had higher rates of severe complications (OR 3.39), increased TPN at discharge (OR 4.32), and increased rates of discharge to nursing facilities (OR 2.57) (all P < 0.05). New IDDM was also associated with a decreased cancer-specific survival.

CONCLUSION

Preoperative HbA1c ≥ 6.25% and blood glucose ≥ 121 mg/dL can accurately identify patients at increased risk of IDDM. These diagnostics may help identify patients in a preoperative setting that may benefit from interventions such as diabetes education or enhanced glucose control preoperatively.

A risk-adjusted analysis of drain use in pancreaticoduodenectomy: Some is good, but more may not be better

BACKGROUND

Intraperitoneal drain placement decreases morbidity and mortality in patients who develop a clinically relevant postoperative pancreatic fistula (CR-POPF) following pancreaticoduodenectomy (PD). It is unknown whether multiple drains mitigate CR-POPF better than a single drain. We hypothesize that multiple drains decrease the complication burden more than a single drain in cases at greater risk for CR-POPF.

METHODS

The Fistula Risk Score (FRS), mitigation strategies (including number of drains placed), and clinical outcomes were obtained from a multi-institutional database of PDs performed from 2003 to 2020. Outcomes were compared between cases utilizing 0, 1, or 2 intraperitoneal drains. Multivariable regression analysis was used to evaluate the optimal drainage approach.

RESULTS

A total of 4,292 PDs used 0 (7.3%), 1 (45.2%), or 2 (47.5%) drains with an observed CR-POPF rate of 9.6%, which was higher in intermediate/high FRS zone cases compared with negligible/low FRS zone cases (13% vs 2.4%, P < .001). The number of drains placed also correlated with FRS zone (median of 2 in intermediate/high vs 1 in negligible/low risk cases). In intermediate/high risk cases, the use of 2 drains instead of 1 was not associated with a reduced rate of CR-POPF, average complication burden attributed to a CR-POPF, reoperations, or mortality. Obviation of drains was associated with significant increases in complication burden and mortality - regardless of the FRS zone.

CONCLUSION

In intermediate/high risk zone cases, placement of a single drain or multiple drains appears to mitigate the complication burden while use of no drains is associated with inferior outcomes.

Intramuscular lipoma of the scapular region

Intramuscular lipomas are rare, benign soft tissue neoplasms characterized by infiltrative growth into muscle tissue or between muscle fibers. These benign tumors can present similarly to malignant soft tissue neoplasms, such as liposarcomas. Unlike subcutaneous lipomas, intramuscular lipomas require diagnostic imaging to better distinguish the tumor and rule out alternative, malignant etiologies. It is imperative that dermatologists are able to identify this rare lipoma variant and have a thorough understanding of the diagnosis, imaging, and treatment options for this uncommon soft tissue tumor. Our case serves as a reminder for dermatologists to be cognizant of this rare tumor and aware of the importance of diagnostic testing in ruling out similarly-presenting, soft tissue malignancies.

Clinical Translation and Evaluation of a Handheld and Biocompatible Mass Spectrometry Probe for Surgical Use

BACKGROUND

Intraoperative tissue analysis and identification are critical to guide surgical procedures and improve patient outcomes. Here, we describe the clinical translation and evaluation of the MasSpec Pen technology for molecular analysis of in vivo and freshly excised tissues in the operating room (OR).

METHODS

An Orbitrap mass spectrometer equipped with a MasSpec Pen interface was installed in an OR. A "dual-path" MasSpec Pen interface was designed and programmed for the clinical studies with 2 parallel systems that facilitated the operation of the MasSpec Pen. The MasSpec Pen devices were autoclaved before each surgical procedure and were used by surgeons and surgical staff during 100 surgeries over a 12-month period.

RESULTS

Detection of mass spectral profiles from 715 in vivo and ex vivo analyses performed on thyroid, parathyroid, lymph node, breast, pancreatic, and bile duct tissues during parathyroidectomies, thyroidectomies, breast, and pancreatic neoplasia surgeries was achieved. The MasSpec Pen enabled gentle extraction and sensitive detection of various molecular species including small metabolites and lipids using a droplet of sterile water without causing apparent tissue damage. Notably, effective molecular analysis was achieved while no limitations to sequential histologic tissue analysis were identified and no device-related complications were reported for any of the patients.

CONCLUSIONS

This study shows that the MasSpec Pen system can be successfully incorporated into the OR, allowing direct detection of rich molecular profiles from tissues with a seconds-long turnaround time that could be used to inform surgical and clinical decisions without disrupting tissue analysis workflows.

Natural killer cells and cytotoxic T lymphocytes are required to clear solid tumor in a patient-derived xenograft

Existing patient-derived xenograft (PDX) mouse models of solid tumors lack a fully tumor donor-matched, syngeneic, and functional immune system. We developed a model that overcomes these limitations by engrafting lymphopenic recipient mice with a fresh, undisrupted piece of solid tumor, whereby tumor-infiltrating lymphocytes (TILs) persisted in the recipient mice for several weeks. Successful tumor engraftment was achieved in 83% to 89% of TIL-PDX mice, and these were seen to harbor exhausted immuno-effector as well as functional immunoregulatory cells persisting for at least 6 months postengraftment. Combined treatment with interleukin-15 stimulation and immune checkpoint inhibition resulted in complete or partial tumor response in this model. Further, depletion of cytotoxic T lymphocytes and/or natural killer cells before combined immunotherapy revealed that both cell types were required for maximal tumor regression. Our TIL-PDX model provides a valuable resource for powerful mechanistic and therapeutic studies in solid tumors.

Abstract 624: Clinical evaluation of the MasSpec Pen technology for rapid diagnosis and margin assessment in pancreatic cancer surgery

Precise removal of pancreatic ductal adenocarcinoma (PDAC) with microscopically negative margins, commonly assessed by frozen section analysis, is associated with longer disease-free survival. However, histologic complexities and tissue-processing artifacts can render frozen section analysis of PDAC margins a challenging and time-consuming task, with reported accuracies dependent on the skillset and subspecialty of the pathologist on call. We developed the MasSpec Pen, a handheld device coupled to a mass spectrometer, for rapid (~15 s) and nondestructive molecular analysis and diagnosis of tissues. The MasSpec Pen supplies a discrete water droplet onto a tissue's surface, allowing diagnostic metabolites and lipids to be extracted into the droplet and then transmitted into a mass spectrometer for analysis. Here, we evaluate the performance of the MasSpec Pen for intraoperative diagnosis of PDAC in human pancreatic and bile duct margins. Pancreatic and bile duct tissue samples (N=157) were obtained from the Cooperative Human Tissue Network and Baylor College of Medicine and stored at -80°C prior to analysis. A Q Exactive mass spectrometer (Thermo Scientific) coupled to the MasSpec Pen was used for analysis of thawed samples in the negative ion mode. Tissues were then cryo-sectioned, H&E stained, and blindly evaluated by a pathologist. Based on the distinct molecular profiles acquired, we generated two statistical classifiers using lasso penalized logistic regression for distinguishing PDAC from healthy pancreas and bile duct tissue based on a sparse set of molecular features indicative of disease state. For distinguishing normal pancreas from PDAC, an overall accuracy of 91.5%, sensitivity of 95.5%, and specificity of 89.7% was achieved for training, validation, and test sets. Classification results for discriminating normal bile duct from PDAC had an overall accuracy of 95%, sensitivity of 92%, and specificity of 100% in training and validation. We have begun clinical testing of the MasSpec Pen in human surgeries following its successful translation to an operating room at Texas Medical Center. To date, the MasSpec Pen has been used to analyze in vivo and fresh ex vivo tissue in 19 pancreatic surgeries. When predicting on 64 intraoperative analyses using classification models built on banked data, 93.8% agreement with final postoperative pathology reports was achieved. While further validation studies are needed, our results show that the MasSpec Pen can distinguish PDAC from normal pancreas and bile duct tissues with high accuracy and is compatible for in vivo use, suggesting this technology may be valuable for near real-time margin evaluation during pancreatic oncologic surgeries.

Citation Format: Mary E. King, Jialing Zhang, John Q. Lin, Kyana Y. Garza, Rachel J. DeHoog, Clara L. Feider, Alena V. Bensussan, Marta Sans, Anna Krieger, Sunil Badal, Michael F. Keating, Sadhna Dhingra, Wendong Yu, George Van Buren, Christopher Pirko, Kirtan Brahmbhatt, William E. Fisher, James W. Suliburk, Livia S. Eberlin. Clinical evaluation of the MasSpec Pen technology for rapid diagnosis and margin assessment in pancreatic cancer surgery [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 624.

Diagnostic Laparoscopy Improves Staging of Malignant Pleural Mesothelioma With Routine Positron Emission Tomography Imaging

BACKGROUND

With a multimodal treatment strategy, cytoreductive surgery extends survival in malignant pleural mesothelioma. Improving the accuracy of staging can refine patient selection. Our objective was to determine whether diagnostic laparoscopy (DL) improves staging for patients with malignant pleural mesothelioma with the routine use of positron emission tomography (PET).

METHODS

We performed a retrospective review of our prospectively maintained database from February 2014 to May 2019. Inclusion criteria were patients who had disease in the chest that was deemed potentially resectable by radiographic criteria and who underwent DL as part of the staging evaluation before surgery.

RESULTS

Of 187 patients (71% men, 80% epithelial) who underwent DL during staging, 76% proceeded to surgery; 22% were unresectable at exploratory thoracotomy and 78% underwent resection (pleurectomy and decortication, 68%; extrapleural pneumonectomy, 32%). Also, 89% had a PET computed tomography (CT), and 11% had a preoperative CT without PET. DL revealed peritoneal disease in 17%. Among patients with pathologically proven disease at DL, 77% had negative PET-CT imaging. Based on the pathologic findings at DL the sensitivity, specificity, positive predictive value, and negative predictive value of PET-CT were 23%, 78%, 17%, and 83%, respectively. The accuracy of PET-CT was 68%.

CONCLUSIONS

PET-CT has low sensitivity and diagnostic accuracy to identify peritoneal disease in malignant pleural mesothelioma. DL as part of the preoperative staging defines an important subset of patients with bicavitary disease. We recommend DL as a component of staging before surgery.

The Landmark Series: Mitigation of the Postoperative Pancreatic Fistula

Pancreatic fistula has been the defining complication and challenge of pancreatic surgery. Better awareness and mitigation of postoperative pancreatic fistulas has led to significant improvements in morbidity and mortality of pancreatic surgery. The definition and management of pancreatic fistulas has sequentially progressed over the last three decades; the literature ranges from retrospective, observational studies to prospective multicenter randomized controlled trials. The landmark literature contributions driving the perioperative management of pancreatic fistulas are detailed in this article.

A phase I trial targeting advanced or metastatic pancreatic cancer using a combination of standard chemotherapy and adoptively transferred nonengineered, multiantigen specific T cells in the first-line setting (TACTOPS)

4622

Background: Immunotherapy is emerging as a potent therapy for a range of hematologic malignancies and solid tumors. To target pancreatic carcinoma we have developed an autologous, non-engineered T cell therapy using T cell lines that simultaneously target the tumor-associated antigens (TAAs) PRAME, SSX2, MAGEA4, NY-ESO-1 and Survivin. These multiTAA-specific T-cell lines could be consistently prepared by culturing PBMCs in the presence of a Th1-polarizing/pro-proliferative cytokine cocktail, and adding autologous pepmix-loaded DCs as APCs. Methods: Patients with locally advanced or metastatic pancreatic adenocarcinoma who achieved cancer control with three months of standard chemotherapy were eligible to receive up to 6 infusions of multiTAA T-cells (fixed dose - 1x107 cells/m2). While also continuing the same chemotherapy, T-cells were given at monthly intervals from month four, onwards. The primary study endpoints were safety and feasibility of completing all 6 planned infusions, with secondary and tertiary endpoints including anti-tumor effects, patient survival, in vivo expansion and T cell persistence of the infused cells as well as recruitment of the endogenous immune system. Results: Between June 2018 and December 2019, we treated 13 patients with multiTAA T-cells. For 12/13 patients, we generated sufficient cells for all 6 planned doses; 2 doses were available for the remaining patient. Of the 13 patients, 8 maintained cancer control for a longer than expected duration, compared to historical controls. With administration of T-cells, 3 of these 8 patients had partial responses and 1 patient had a radiographic complete response (per RECIST). These responses were seen in patients with metastatic cancer. Notably, no patient had infusion-related systemic- or neuro-toxicity. Thus, infusion of autologous multiTAA-targeted T cells directed to PRAME, SSX2, MAGEA4, NY-ESO-1 and Survivin has been safe and provided durable clinical benefit to patients with pancreatic adenocarcinoma. Conclusions: Autologous, TAA cytotoxic T-cells can reliably be generated and safely administered to patients in conjunction with standard of care chemotherapy. In some patients, addition of T-cells may extend duration of first line therapy cancer control and induce additional tumor responses, and activation of the endogenous immune system has been documented in all patients. Exploration in a higher phase study is warranted. Clinical trial information: NCT03192462 .

Long-Term Assessment of Pancreatic Function After Pancreatectomy for Cystic Neoplasms

BACKGROUND

With advances in cross-sectional imaging, pancreatic cysts are more frequently diagnosed and have become a common indication for pancreatectomy. The impact of pancreatectomy in these patients is important. The purpose of this study was to assess short-term outcomes, long-term nutritional status, quality of life (QOL), and pancreas function after pancreatectomy for cystic neoplasms.

MATERIALS AND METHODS

At a single institution, patients at least 3 y post-pancreatectomy for benign cystic neoplasms were identified. Using a validated questionnaire, short-term outcomes, long-term outcomes including endocrine and exocrine insufficiency, long-term nutritional status, and preoperative and postoperative QOL were compared based on operation and indication for resection.

RESULTS

Among 102 eligible patients, 70 had valid contact information and 51 (72.9%) agreed to participate. Median follow-up was 6 (4-8) y. Patients undergoing pancreatoduodenectomy for benign cysts had higher morbidity than a similar cohort resected for pancreatic adenocarcinoma (patients with at least 1 ≥ grade 2 complication [49.0% versus 31.6%, P = 0.038]). After long-term follow-up, pancreatectomy did not significantly affect perceived QOL. Half of patients had mild-moderate or severe malnourishment, but pancreatic enzyme replacement was reported by only 4 (7.8%) patients. New-onset diabetes was present in 15 (29.4%) patients with median time-to-diagnosis of 6 (1-12) mo after resection.

CONCLUSIONS

Pancreatectomy for benign cysts did not negatively impact patients' perceived QOL. However, after long-term follow-up, malnutrition and pancreatic insufficiency occurred in a significant percentage and may be greater than previously estimated. Consideration of short- and long-term outcomes should factor into preoperative counseling, especially in cysts with minimal risk of progression to malignancy.

Mesothelin and TGF-α predict pancreatic cancer cell sensitivity to EGFR inhibitors and effective combination treatment with trametinib

Clinical trials of EGFR inhibitors in combination with gemcitabine for the treatment of pancreatic ductal adenocarcinoma (PDAC) have generated mixed results partially due to the poorly defined effectiveness of EGFR inhibitors in PDAC. Here, we studied a panel of PDAC cell lines to compare the IC50s of the EGFR inhibitors gefitinib and cetuximab. We found that gefitinib induced biphasic inhibition in over 50% of PDAC cells, with the initial growth inhibition occurring at nanomolar concentrations and a second growth inhibition occurring outside the clinical range. In contrast to gefitinib, cetuximab produced a single phase growth inhibition in a subset of PDAC cells. Using this sensitivity data, we screened for correlations between cell morphology proteins and EGFR ligands to EGFR inhibitor sensitivity, and found that mesothelin and the EGFR ligand TGF-α have a strong correlation to gefitinib and cetuximab sensitivity. Analysis of downstream signaling pathways indicated that plc-γ1 and c-myc were consistently inhibited by EGFR inhibitor treatment in sensitive cell lines. While an inconsistent additive effect was observed with either cetuximab or gefitinib in combination with gemcitabine, the cell pathway data indicated consistent ERK activation, leading us to pursue EGFR inhibitors in combination with trametinib, a MEK1/2 inhibitor. Both cetuximab and gefitinib in combination with trametinib produced an additive effect in all EGFR sensitive cell lines. Our results indicate that mesothelin and TGF-α can predict PDAC sensitivity to EGFR inhibitors and a combination of EGFR inhibitors with trametinib could be a novel effective treatment for PDAC.

Evidence Versus Practice in Early Drain Removal After Pancreatectomy

BACKGROUND

Early drain removal when postoperative day (POD) one drain fluid amylase (DFA) was ≤5000 U/L reduced complications in a previous randomized controlled trial. We hypothesized that most surgeons continue to remove drains late and this is associated with inferior outcomes.

METHODS

We assessed the practice of surgeons in a prospectively maintained pancreas surgery registry to determine the association between timing of drain removal with demographics, comorbidities, and complications. We selected patients with POD1 DFA ≤5000 U/L and excluded those without drains, and subjects without data on POD1 DFA or timing of drain removal. Early drain removal was defined as ≤ POD5.

RESULTS

Two hundred and forty four patients met inclusion criteria. Only 90 (37%) had drains removed early. Estimated blood loss was greater in the late removal group (190 mL versus 100 mL, P = 0.005) and pathological findings associated with soft gland texture were more frequent (97 [63%] versus 35 [39%], P < 0.0001). Patients in the late drain removal group had more complications (84 [55%] versus 30 [33%], P = 0.001) including pancreatic fistula (55 [36%] versus 4 [4%], P < 0.0001), delayed gastric emptying (27 [18%] versus 3 [3%], P = 0.002), and longer length of stay (7 d versus 5 d, P < 0.0001). In subset analysis for procedure type, complications and pancreatic fistula remained significant for both pancreatoduodenectomy and distal pancreatectomy.

CONCLUSIONS

Despite level one data suggesting improved outcomes with early removal when POD1 DFA is ≤ 5000 U/L, experienced pancreas surgeons more frequently removed drains late. This practice was associated with known risk factors (estimated blood loss, soft pancreas) and may be associated with inferior outcomes suggesting potential for improvement.

SRC-3 inhibition blocks tumor growth of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant and lethal disease with few treatment options. Steroid receptor coactivator-3 (SRC-3, also known as NCOA3, AIB1, pCIP, ACTR, RAC3, TRAM1) sits at the nexus of many growth signaling pathways and has been pursued as a therapeutic target for breast, prostate and lung cancers. In this study, we find that SRC-3 is overexpressed in PDAC and inversely correlates with patient overall survival. Knockdown of SRC-3 reduces pancreatic cancer cell proliferation, migration and invasion in vitro. Additionally, inhibition of SRC-3 using either shRNA or a small molecule inhibitor can significantly inhibit tumor growth in orthotopic pancreatic cancer mouse models. Collectively, this study establishes SRC-3 as a promising therapeutic target for pancreatic cancer treatment.

Abstract B031: Semaphorin 3E promotes pancreatic cancer metastasis through activating stromal cell

Background: Better understanding of the molecular mechanisms of pancreatic adenocarcinoma (PDAC) metastasis is important for the development of effective treatments for this devastating disease. We have previously shown that overexpression of Semaphorin 3E (Sema3E) enhances PDAC cell growth and is associated with poor patient survival. Here, we further determined the effect of Sema3E on stromal cells and the molecular mechanisms contributing to PDAC metastasis. Materials and Methods: Panels of stable PDAC cell lines were generated using either lenti-Sema3E for overexpression or the Crispr/Cas9 system to knock out (KO) Sema3E in both panc28 and panc48 cell lines. The effects of Sema3E overexpression or KO were measured in orthotopically implanted xenograft tumor mouse models in respect to tumor size, metastasis, and survival. After coculture with pancreatic stellate cells (PSCs), the effects of Sema3E on PSC activation were evaluated by GFAP and αSMA staining. Mixtures of PDAC cell lines with PSCs in vivo tumor growth were also evaluated. Result: After orthotopically implanting a panel of Sema3E-overexpressing or knockout panc28 cell lines, we found that the survival span of the sema3E-overexpression cell implant group was significantly shorter than the vector control group (31±9 days vs. 51±15 days) (p&lt;0.05). In addition, more lung metastases were found in the Panc28-Sema3E overexpressing group. Compared to the primary tumor, the lung metastases had increased sema3E expression. Furthermore, Sema3E overexpression promoted PSC activation with a greater ratio of αSMA to GFAP staining when cocultured with PSC cells. Cotransplant of Sema3E-overexpression cells and PSC cells promoted tumor growth and metastasis when compare to Sema3E-overexpressed cells alone. Conclusion: Sema3E overexpression in pancreatic cancer cells promotes tumor growth, lung metastasis, and poor survival. The interaction between Sema3E and PSC cells may play an important role in contributing to tumor growth and metastasis.

Citation Format: Zhengdong Liang, Lin-Kin Yong, George Van Buren, William Fisher, Rosa Hwang, Changyi Chen, Qizhi Cathy Yao. Semaphorin 3E promotes pancreatic cancer metastasis through activating stromal cell [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 B031.

Corrigendum: Whole-genome landscape of pancreatic neuroendocrine tumours

This corrects the article DOI: 10.1038/nature21063.

Nutritional and Metabolic Derangements in Pancreatic Cancer and Pancreatic Resection

Pancreatic cancer is an aggressive malignancy with a poor prognosis. The disease and its treatment can cause significant nutritional impairments that often adversely impact patient quality of life (QOL). The pancreas has both exocrine and endocrine functions and, in the setting of cancer, both systems may be affected. Pancreatic exocrine insufficiency (PEI) manifests as weight loss and steatorrhea, while endocrine insufficiency may result in diabetes mellitus. Surgical resection, a central component of pancreatic cancer treatment, may induce or exacerbate these dysfunctions. Nutritional and metabolic dysfunctions in patients with pancreatic cancer lack characterization, and few guidelines exist for nutritional support in patients after surgical resection. We reviewed publications from the past two decades (1995–2016) addressing the nutritional and metabolic status of patients with pancreatic cancer, grouping them into status at the time of diagnosis, status at the time of resection, and status of nutritional support throughout the diagnosis and treatment of pancreatic cancer. Here, we summarize the results of these investigations and evaluate the effectiveness of various types of nutritional support in patients after pancreatectomy for pancreatic adenocarcinoma (PDAC). We outline the following conservative perioperative strategies to optimize patient outcomes and guide the care of these patients: (1) patients with albumin < 2.5 mg/dL or weight loss > 10% should postpone surgery and begin aggressive nutrition supplementation; (2) patients with albumin < 3 mg/dL or weight loss between 5% and 10% should have nutrition supplementation prior to surgery; (3) enteral nutrition (EN) should be preferred as a nutritional intervention over total parenteral nutrition (TPN) postoperatively; and, (4) a multidisciplinary approach should be used to allow for early detection of symptoms of endocrine and exocrine pancreatic insufficiency alongside implementation of appropriate treatment to improve the patient’s quality of life.

Whole-genome landscape of pancreatic neuroendocrine tumours

The diagnosis of pancreatic neuroendocrine tumours (PanNETs) is increasing owing to more sensitive detection methods, and this increase is creating challenges for clinical management. We performed whole-genome sequencing of 102 primary PanNETs and defined the genomic events that characterize their pathogenesis. Here we describe the mutational signatures they harbour, including a deficiency in G:C > T:A base excision repair due to inactivation of MUTYH, which encodes a DNA glycosylase. Clinically sporadic PanNETs contain a larger-than-expected proportion of germline mutations, including previously unreported mutations in the DNA repair genes MUTYH, CHEK2 and BRCA2. Together with mutations in MEN1 and VHL, these mutations occur in 17% of patients. Somatic mutations, including point mutations and gene fusions, were commonly found in genes involved in four main pathways: chromatin remodelling, DNA damage repair, activation of mTOR signalling (including previously undescribed EWSR1 gene fusions), and telomere maintenance. In addition, our gene expression analyses identified a subgroup of tumours associated with hypoxia and HIF signalling.

Ampullary Cancers Harbor ELF3 Tumor Suppressor Gene Mutations and Exhibit Frequent WNT Dysregulation

The ampulla of Vater is a complex cellular environment from which adenocarcinomas arise to form a group of histopathologically heterogenous tumors. To evaluate the molecular features of these tumors, 98 ampullary adenocarcinomas were evaluated and compared to 44 distal bile duct and 18 duodenal adenocarcinomas. Genomic analyses revealed mutations in the WNT signaling pathway among half of the patients and in all three adenocarcinomas irrespective of their origin and histological morphology. These tumors were characterized by a high frequency of inactivating mutations of ELF3, a high rate of microsatellite instability, and common focal deletions and amplifications, suggesting common attributes in the molecular pathogenesis are at play in these tumors. The high frequency of WNT pathway activating mutation, coupled with small-molecule inhibitors of β-catenin in clinical trials, suggests future treatment decisions for these patients may be guided by genomic analysis.

Pancreatic cancer disparities in African Americans

OBJECTIVES

Pancreatic cancer is the fourth leading cause of cancer-related deaths in the United States. The incidence of pancreatic cancer in African Americans is 50% to 90% higher than the incidence in other racial groups. African Americans also have the worst prognosis. This is an evidence-based review of pancreatic cancer in African Americans with particular emphasis on baseline characteristics, treatment, and survival.

METHODS

We queried PubMed in search for articles describing racial disparities in pancreatic cancer. Two categories of terms were "anded" together: pancreatic cancer terms and race terms. The last search was performed on November 14, 2013.

RESULTS

We summarized the data on pancreatic cancer baseline characteristics, treatment, and survival for African Americans that we obtained from the following databases: (1) Surveillance, Epidemiology, and End Results, 1988-2008; (2) California Cancer Registry 1988-1998; (3) Cancer Survivor Program of Orange County/San Diego Imperial Organization for Cancer Control, 1988-1998; and (4) Harris County, 1998-2010.

CONCLUSIONS

Overall, pancreatic cancer survival of African Americans has not significantly improved over the past several decades despite advances in multimodality therapy; African Americans continue to face worse outcomes than whites. Although baseline characteristics, treatment, and biological factors offer some explanation, they do not completely explain the disparities in incidence and survival.

A randomized prospective multicenter trial of pancreaticoduodenectomy with and without routine intraperitoneal drainage

OBJECTIVE

To test by randomized prospective multicenter trial the hypothesis that pancreaticoduodenectomy (PD) without the use of intraperitoneal drainage does not increase the frequency or severity of complications.

BACKGROUND

Some surgeons have abandoned the use of drains placed during pancreas resection.

METHODS

We randomized 137 patients to PD with (n = 68, drain group) and without (n = 69, no-drain group) the use of intraperitoneal drainage and compared the safety of this approach and spectrum of complications between the 2 groups.

RESULTS

There were no differences between drain and no-drain cohorts in demographics, comorbidities, pathology, pancreatic duct size, pancreas texture, baseline quality of life, or operative technique. PD without intraperitoneal drainage was associated with an increase in the number of complications per patient [1 (0-2) vs 2 (1-4), P = 0.029]; an increase in the number of patients who had at least 1 ≥grade 2 complication [35 (52%) vs 47 (68%), P = 0.047]; and a higher average complication severity [2 (0-2) vs 2 (1-3), P = 0.027]. PD without intraperitoneal drainage was associated with a higher incidence of gastroparesis, intra-abdominal fluid collection, intra-abdominal abscess (10% vs 25%, P = 0.027), severe (≥grade 2) diarrhea, need for a postoperative percutaneous drain, and a prolonged length of stay. The Data Safety Monitoring Board stopped the study early because of an increase in mortality from 3% to 12% in the patients undergoing PD without intraperitoneal drainage.

CONCLUSIONS

This study provides level 1 data, suggesting that elimination of intraperitoneal drainage in all cases of PD increases the frequency and severity of complications.

Phase II study of induction fixed-dose rate gemcitabine and bevacizumab followed by 30 Gy radiotherapy as preoperative treatment for potentially resectable pancreatic adenocarcinoma

BACKGROUND

Eighty percent of patients with resected pancreatic ductal carcinoma (PDC) experience treatment failure within 2 years. We hypothesized that preoperative fixed-dose rate (FDR) gemcitabine (GEM) combined with the angiogenesis inhibitor bevacizumab (BEV) and accelerated 30 Gy radiotherapy (RT) would improve outcomes among patients with potentially resectable PDC.

METHODS

This phase II trial tested induction FDR GEM (1,500 mg/m(2)) plus BEV (10 mg/kg IV) every 2 weeks for three cycles followed by accelerated RT (30 Gy in 10 fractions) plus BEV directed at gross tumor volume plus a 1-2 cm vascular margin. Subjects underwent laparoscopy and resection after day 85. Therapy was considered effective if the complete pathologic response rate exceeded 10 % and the margin-negative resection rate exceeded 80%.

RESULTS

Fifty-nine subjects were enrolled; 29 had potential portal vein involvement. Two grade 4 (3.4%) and 19 grade 3 toxicities (32.8%) occurred. Four subjects manifested radiographic progression, and 10 had undetected carcinomatosis. Forty-three pancreatic resections (73%) were performed, including 19 portal vein resections (44%). Margin-negative outcomes were observed in 38 (88%, 95% confidence interval [CI] 75-96), with one complete pathologic response (2.3%; 95% CI 0.1-12). There were seven (6 grade 3; 1 grade 4) wound complications (13%). Median overall survival for the entire cohort was 16.8 months (95% CI 14.9-21.3) and 19.7 months (95% CI 16.5-28.2) after resection.

CONCLUSIONS

Induction therapy with FDR GEM and BEV, followed by accelerated BEV/RT to 30 Gy, was well tolerated. Although both effectiveness criteria were achieved, survival outcomes were equivalent to published regimens.

Margin distance as an independent predictor of survival after R0 resection for pancreatic adenocarcinoma

321

Background: Microscopic tumor at the surgical margin is a predictor of recurrence and poor survival for pancreatic ductal adenocarcinoma (PDA). However, the impact of distance between the surgical margin and microscopic tumor on survival remains controversial. We hypothesized that margin distance (MD) would correlate with disease free survival (DFS) and overall survival (OS) in R0 resected PDA.

Methods: Retrospective analysis of 191 resections for PDA. Margin distance was measured (0-1, 1-2, 2-4, 4-10, and > 10 mm) and categorized by location. Parameters including age, gender, BMI, TNM, AJCC stage, lymph node (LN) ratio, vascular and perineural invasion, vein resection, and adjuvant therapy were analyzed. Primary endpoints were DFS and disease specific OS. Univariate analysis was used to estimate factors associated with outcomes. The log rank test was applied to selected group comparisons.

Results: 149 (78%) R0 outcomes were analyzed. 118 (79%) patients received adjuvant chemotherapy, 31 of whom also received XRT. Univariate analysis demonstrated reduced DFS (HR = 1.65, 95% CI = 1.13 – 2.48, p = .009) and OS (HR = 1.52 95% CI =.98 – 2.35, p = .059) among patients with margins ≤ 2mm compared to margins > 2mm. In addition LN status, LN ratio, tumor size, AJCC stage, vascular invasion, perineural invasion and adjuvant chemotherapy were found to influence OS on univariate analysis. Adjuvant XRT had no measurable effect on DFS or OS. Following adjustment for covariates in a multivariate model, margin distance >2mm did not correlate with DFS (HR = 1.14, 95%CI = .73 – 1.78, p = .57) or OS (HR = 1.13 95% CI = .69 – 1.85, p = .63), whereas adjuvant chemotherapy and presence of vascular invasion significantly affected OS (P=0.0006 and P=0.008 respectively). The retroperitoneal margin was the margin most commonly in close proximity to tumor (43% of Whipple), although there was no correlation between the closest margin and DFS (p=0.94) or OS (p=0.94).

Conclusions: Margin distance is not an independent predictor of DFS or OS after R0 resection for PDA. Irrespective of margin distance, adjuvant chemotherapy, but not XRT, was associated with improved OS.

Phase II trial of fixed-dose rate gemcitabine, bevacizumab, and concurrent 30 gy radiotherapy as preoperative treatment for potentially resectable pancreatic adenocarcinoma

258

Background: Effective multimodality treatment for localized pancreatic cancer is elusive. We hypothesized that preoperative fixed-dose rate (FDR) gemcitabine (GEM) combined with short-course radiotherapy (RT) and the angiogenesis inhibitor bevacizumab (BEV) would improve margin negative surgical outcomes and complete pathological response rates.

Methods: Multisite phase II trial evaluating all potentially-resectable pancreatic adenocarcinoma without major arterial involvement or portal venous occlusion. Dual primary endpoints included complete pathological response and margin negative resection rates of 10% and 80%. Subjects received FDR GEM on days 1, 15, and 29 combined with BEV (10 mg/kg IV), followed on day 43 by BEV and concurrent 30 Gy RT (3 Gy/fraction) over 10 days. After restaging, subjects underwent laparoscopy and possible resection after day 85. Stopping criteria required continuous monitoring of serious wound complications.

Results: 58 subjects enrolled, of which 29 (50%) had suspected venous involvement. 57 completed treatment without dose-limiting toxicity or delays in surgery. Two grade 4 (3.4%) and 17 grade 3 toxicities (28.8%) occurred. Four patients progressed before surgery. 54 subjects underwent laparoscopy; ten had unexpected carcinomatosis, and one was unresectable. 43 subjects were resected (74%; 33 pancreatico-duodenectomy, 8 distal pancreatectomy, 1 total pancreatectomy, 1 Appleby); 19 (44%) required portal vein resection. Margin negative outcome was achieved in 38 (88%, 95% CI: 75%-96%) with one complete pathological response (2.3%; 95% CI: 0.1%- 12%) and seven (6 grade 3; 1 grade 4) wound complications (13%). Median overall survival (OS) was 16.3 months (95% CI: 13.9 -22.1) and 21.3 months (95% CI: 15.0-32.9) after resection. Median progression-free survival (PFS) was 5.7 months (95% CI: 3.9-9.1) and 9.9 months (95% CI: 5.7 to 14.1) after resection, with 7 local and 21 distant recurrences.

Conclusions: Combination therapy was well-tolerated and was within statistical design parameters for the primary endpoints despite a significant proportion of borderline tumors.

Hepatocellular carcinoma survival in uninsured and underinsured patients

BACKGROUND

The incidence of hepatitis C virus (HCV) and hepatocellular carcinoma (HCC) is increasing. The purpose of this study is to establish baseline survival in a medically-underserved population and to evaluate the effect of HCV seropositivity on our patient population.

MATERIALS AND METHODS

We reviewed clinicopathologic parameters from a prospective tumor registry and medical records from the Harris County Hospital District (HCHD). Outcomes were compared using Kaplan-Meier survival analysis and log-rank tests.

RESULTS

A total of 298 HCC patients were identified. The median survival for the entire cohort was 3.4 mo. There was no difference in survival between the HCV seropositive and the HCV seronegative groups (3.6 mo versus 2.6 mo, P = 0.7). Patients with a survival <1 mo had a significant increase in αfetoprotein (AFP), international normalized ratio (INR), model for end-stage liver disease (MELD) score, and total bilirubin and decrease in albumin compared with patients with a survival ≥ 1 mo.

CONCLUSIONS

Survival for HCC patients in the HCHD is extremely poor compared with an anticipated median survival of 7 mo reported in other studies. HCV seropositive patients have no survival advantage over HCV seronegative patients. Poorer liver function at diagnosis appears to be related to shorter survival. Further analysis into variables contributing to decreased survival is needed.

Targeting the urokinase plasminogen activator receptor with a monoclonal antibody impairs the growth of human colorectal cancer in the liver

BACKGROUND

Urokinase plasminogen activator receptor (uPAR) expression has been shown to correlate with poor prognosis in colorectal cancer (CRC). The authors hypothesized that targeting uPAR, a receptor involved in cell proliferation, migration, invasion, adhesion, and angiogenesis, would impair the growth of CRC in the liver, the most common site of metastasis.

METHODS

Human CRC cell lines were examined for uPAR expression by Western blot analysis. The in vitro effects of the uPAR monoclonal antibody (MoAb) (ATN-658) were tested in proliferation and migration assays. For in vivo studies, human HCT116 CRC cells were injected directly into the livers of mice in 2 separate studies, the first to determine the effect of therapy with ATN-658 on small-volume disease (therapy begun on Day 4), and a second study to determine the effect of therapy on established disease (therapy begun on Day 12). Mice were randomized to receive either nonspecific immunoglobulin G MoAb (control) or ATN-658, and were sacrificed 1 month after tumor implantation.

RESULTS

uPAR was expressed by all CRC cell lines studied. In vitro, ATN-658 had minimal effect on CRC proliferation in monolayers, but significantly decreased CRC cell migration. In vivo, ATN-658 lead to significant reductions in tumor growth versus control when initiated either 4 or 12 days after tumor implantation (-65% vs control [P < or = .05] and -85% vs control [P < or = .05]). ATN-658 significantly inhibited in vivo tumor cell proliferation in both studies.

CONCLUSIONS

uPAR MoAb therapy impaired CRC tumor growth in the liver in both small-volume and large-volume disease models.

Effect of chemotherapeutic stress on induction of vascular endothelial growth factor family members and receptors in human colorectal cancer cells

Vascular endothelial growth factor (VEGF) is induced by stress. We determined whether chemotherapy (genotoxic stress) could induce expression of VEGF and VEGF receptors (VEGFR) in human colorectal cancer cells. The colorectal cancer cell lines HT29, RKO, and HCT116 were acutely exposed to increasing doses of oxaliplatin or 5-fluorouracil for 2, 6, and 24 h in vitro. Expression of VEGF ligand family members, VEGFRs, and signaling intermediates was determined by reverse transcription-PCR and Northern and Western blotting. The effect of oxaliplatin on VEGF-A transcriptional activity was determined by promoter assays. Acute exposure of human colorectal cancer cells to oxaliplatin led to a marked induction of VEGF-A mRNA and protein, whereas 5-fluorouracil alone or when added to oxaliplatin did not cause a further increase in VEGF levels. VEGF-A promoter activity was induced by oxaliplatin exposure. Expression of VEGF-C, placental growth factor, VEGFR-1, and neuropilin-1 levels were also increased when cells were treated with oxaliplatin. Oxaliplatin led to an increase in Akt and Src activation in HT29 cells. In contrast, Akt activation did not change in RKO cells whereas phospho-Src and phospho-p44/42 mitogen-activated protein kinase was dramatic increased by oxaliplatin. Inhibition of Akt or Src activation with wortmannin or PP2 blocked induction of VEGF-A by oxaliplatin in HT29 or RKO cells, respectively. VEGFRs may reflect the adaptive stress responses by which tumor cells attempt to protect themselves from genotoxic stress. Neutralization of prosurvival responses with anti-VEGF therapy might explain, in part, some of the beneficial effects of anti-VEGF therapy when added to chemotherapy.

Effect of Molecular Therapeutics on Liver Regeneration in a Murine Model

Purpose

Unresectable metastatic colorectal cancer (CRC) can be rendered resectable with systemic chemotherapy in approximately 20% of cases. Most patients with metastatic CRC receive chemotherapy with the addition of targeted therapy with anti–vascular endothelial growth factor (VEGF) or anti–epidermal growth factor receptor (EGFR) antibodies. We sought to determine whether anti-VEGF receptor (VEGFR) or anti-EGFR therapy would impair liver regeneration after partial hepatectomy (PH) in mice.

Materials and Methods

Mice underwent either 66% PH or sham laparotomy. In the first experiment, mice in the PH group were randomly assigned to receive daily intraperitoneal injections of monoclonal antibodies (MoABs) to murine VEGFR-2 or nonspecific MoABs (control). In the second experiment, mice in the PH group were randomly assigned to receive intraperitoneal injections of antimurine EGFR or nonspecific (control) MoABs. In both experiments, therapy was initiated the day before surgery and continued until the mice were killed on day 5. Livers were collected and processed.

Results

Anti–VEGFR-2 therapy slightly impaired liver regeneration and hepatic cell proliferation compared with control. Hematoxylin and eosin staining showed no differences in liver morphology. CD105 staining showed decreased levels of activated endothelium in livers in the VEGFR-2 MoAB group. VEGFR-2 MoAB therapy decreased the levels of the cell cycle regulators cyclin D1 and cyclin D3 and the regenerative cytokine interleukin-6. Anti-EGFR therapy had no effect on liver regeneration or cellular proliferation.

Conclusion

Anti–VEGFR-2 therapy slightly impaired liver regeneration in this murine model, whereas anti-EGFR therapy had no effect on liver regeneration.

Functional significance of vascular endothelial growth factor receptors on gastrointestinal cancer cells

Vascular endothelial growth factor (VEGF) has been shown to be the major mediator of physiologic and pathologic angiogenesis. VEGF was initially thought to be an endothelial cell specific ligand, but recently, VEGF has been shown to mediate tumor cell function via activation of receptors on tumor cells themselves. Here, we review the expression patterns and binding profiles of the VEGF receptors and their ligands on gastrointestinal tumor cells. Furthermore, we describe the current knowledge in regards to the function of these receptors on tumor cells. Elucidating the function of VEGF receptors on tumor cells should help us to better understand the potential mechanisms of action of anti-VEGF therapies.

Therapeutic targeting of neuropilin-2 on colorectal carcinoma cells implanted in the murine liver

BACKGROUND

Neuropilin-2 (NRP2) is a high-affinity kinase-deficient receptor for vascular endothelial growth factor (VEGF) and semaphorin 3F. We investigated its function in human colorectal cancers.

METHODS

Immunohistochemistry and immunoblotting were used to assess NRP2 expression levels in colorectal tumors and colorectal cancer cell lines, respectively. HCT-116 colorectal cancer cells stably transfected with short hairpin RNA (shRNAs) against NRP2 or control shRNAs were assayed for proliferation by the tetrazolium salt 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and for activation of the VEGFR1 pathway by immunoblotting. Soft agar assays, Annexin V staining, and Boyden chamber assays were used to examine anchorage-independent growth, apoptosis in response to hypoxia, and cell migration/invasion, respectively, in HCT-116 transfectants. Tumor growth and metastasis were analyzed in mice (groups of 10) injected with shRNA-expressing HCT-116 cells. The effect of in vivo targeting of NRP2 by small interfering RNA (siRNA) on the growth of hepatic colorectal tumors derived from luciferase-expressing HCT-116 cells was assessed by measuring changes in bioluminescence and final tumor volumes. All statistical tests were two-sided.

RESULTS

NRP2 expression was substantially higher in tumors than in adjacent mucosa. HCT-116 transfectants with reduced NRP2 levels had reduced VEGFR1 signaling, but proliferation was unchanged. Anchorage-independent growth, survival under hypoxic conditions, and motility/invasiveness were also reduced. In vivo, HCT-116 transfectants with reduced NRP2 demonstrated decreased tumor growth, fewer metastases, and increased apoptosis compared with control cells. Hepatic colorectal tumors in mice treated with NRP2 siRNAs were statistically significantly smaller than those in mice treated with control siRNAs (at 28 days after implantation, mean control siRNAs = 420 mm3, mean NRP2 siRNAs = 36 mm3, NRP2 vs control: difference = 385 mm3, 95% confidence interval = 174 mm3 to 595 mm3, P = .005).

CONCLUSION

NRP2 on colorectal carcinoma cells is important for tumor growth and is a potential therapeutic target in human cancers where it is expressed.

Sequential stenotic strictures of the small bowel leading to obstruction

Small bowel obstructions (SBOs) are primarily caused by adhesions, hernias, neoplasms, or inflammatory strictures. Intraluminal strictures are an uncommon cause of SBO. This report describes our findings in a unique case of sequential, stenotic intraluminal strictures of the small intestine, discusses the differential diagnosis of intraluminal intestinal strictures, and reviews the literature regarding intraluminal pathology.

The development and characterization of a human midgut carcinoid cell line

PURPOSE

Gastrointestinal neuroendocrine tumors (NET) are rare heterogeneous tumors that hypersecrete neuropeptides. The scarcity of good gastrointestinal NET models has limited the ability to study potential therapeutic agents. We describe and characterize the establishment of a human midgut carcinoid tumor cell line carcinoid tumor 2 (CNDT2).

EXPERIMENTAL DESIGN

Tumor cells (CNDT2) were isolated from a liver metastasis from a patient with a primary ileal carcinoid. After 9 weeks in culture, the cells were plated in soft agar, and cells from a single colony were put back in culture (CNDT2.1). Those CNDT2.1 cells were injected s.c. into nude mice. Cells were isolated from a single resultant tumor (CNDT2.5), cultured, and characterized by electron microscopy, reverse transcription-PCR, serotonin enzyme immunoassay, Western blotting, and immunohistochemical analysis for NET markers and potential therapeutic targets.

RESULTS

CNDT2 cells grew in monolayers in vitro, formed colonies in soft agar, and formed tumors in mice. Electron microscopy revealed round, pleomorphic, electron-dense neurosecretory granules characteristic of NETs. Tumor xenografts exhibited the appearance of NETs with small "salt-and-pepper" nuclei on H&E staining and chromogranin A, synaptophysin, and CD56 on immunohistochemical staining. CNDT2.5 cells produced serotonin and expressed insulin-like growth factor receptor-I, platelet-derived growth factor receptor-beta, vascular endothelial growth factor receptor-1, cMET, epidermal growth factor receptor, neuropilin-1, and somatostatin receptors 1 to 5. Cytogenetic analysis revealed the presence of deletions at 2p and 6q and numerous translocations.

CONCLUSION

The establishment of this human midgut carcinoid tumor cell line may serve as a useful model system for studying cell biology and novel targeted agents in preclinical models.

The role of nitric oxide in mediating tumour blood flow

Nitric oxide (NO) is a ubiquitous molecule with a myriad of physiological and pathophysiological roles. It has numerous direct and indirect effects on tumour vasculature as both a regulatory and effector molecule. NO affects tumour blood flow through its effects on tumour angiogenesis, vascular tone and vascular permeability, partly via its interaction with vascular endothelial growth factor. In this review, the authors examine the basic tenants of NO biology, the association of NO with tumour progression, and the role NO plays in mediating alterations in vascular functions in tumours.