Nigel B. Jamieson

Whole genomes redefine the mutational landscape of pancreatic cancer

Pancreatic cancer remains one of the most lethal of malignancies and a major health burden. We performed whole-genome sequencing and copy number variation (CNV) analysis of 100 pancreatic ductal adenocarcinomas (PDACs). Chromosomal rearrangements leading to gene disruption were prevalent, affecting genes known to be important in pancreatic cancer (TP53, SMAD4, CDKN2A, ARID1A and ROBO2) and new candidate drivers of pancreatic carcinogenesis (KDM6A and PREX2). Patterns of structural variation (variation in chromosomal structure) classified PDACs into 4 subtypes with potential clinical utility: the subtypes were termed stable, locally rearranged, scattered and unstable. A significant proportion harboured focal amplifications, many of which contained druggable oncogenes (ERBB2, MET, FGFR1, CDK6, PIK3R3 and PIK3CA), but at low individual patient prevalence. Genomic instability co-segregated with inactivation of DNA maintenance genes (BRCA1, BRCA2 or PALB2) and a mutational signature of DNA damage repair deficiency. Of 8 patients who received platinum therapy, 4 of 5 individuals with these measures of defective DNA maintenance responded.

Mutant p53 drives metastasis and overcomes growth arrest/senescence in pancreatic cancer

TP53 mutation occurs in 50–75% of human pancreatic ductal adenocarcinomas (PDAC) following an initiating activating mutation in the KRAS gene. These p53 mutations frequently result in expression of a stable protein, p53R175H, rather than complete loss of protein expression. In this study we elucidate the functions of mutant p53 (Trp53R172H), compared to knockout p53 (Trp53fl), in a mouse model of PDAC. First we find that although KrasG12D is one of the major oncogenic drivers of PDAC, most KrasG12D-expressing pancreatic cells are selectively lost from the tissue, and those that remain form premalignant lesions. Loss, or mutation, of Trp53 allows retention of the KrasG12D-expressing cells and drives rapid progression of these premalignant lesions to PDAC. This progression is consistent with failed growth arrest and/or senescence of premalignant lesions, since a mutant of p53, p53R172P, which can still induce p21 and cell cycle arrest, is resistant to PDAC formation. Second, we find that despite similar kinetics of primary tumor formation, mutant p53R172H, as compared with genetic loss of p53, specifically promotes metastasis. Moreover, only mutant p53R172H-expressing tumor cells exhibit invasive activity in an in vitro assay. Importantly, in human PDAC, p53 accumulation significantly correlates with lymph node metastasis. In summary, by using ‘knock-in’ mutations of Trp53 we have identified two critical acquired functions of a stably expressed mutant form of p53 that drive PDAC; first, an escape from KrasG12D-induced senescence/growth arrest and second, the promotion of metastasis.

Rab25 and CLIC3 Collaborate to Promote Integrin Recycling from Late Endosomes/Lysosomes and Drive Cancer Progression

Summary Here we show that Rab25 permits the sorting of ligand-occupied, active-conformation α5β1 integrin to late endosomes/lysosomes. Photoactivation and biochemical approaches show that lysosomally targeted integrins are not degraded but are retrogradely transported and recycled to the plasma membrane at the back of invading cells. This requires CLIC3, a protein upregulated in Rab25-expressing cells and tumors, which colocalizes with active α5β1 in late endosomes/lysosomes. CLIC3 is necessary for release of the cell rear during migration on 3D matrices and is required for invasion and maintenance of active Src signaling in organotypic microenvironments. CLIC3 expression predicts lymph node metastasis and poor prognosis in operable cases of pancreatic ductal adenocarcinoma (PDAC). The identification of CLIC3 as a regulator of a recycling pathway and as an independent prognostic indicator in PDAC highlights the importance of active integrin trafficking as a potential drive to cancer progression in vivo.

Paradoxical Elevation in Adiponectin Concentrations in Women With Preeclampsia

Abstract—Adiponectin is a recently identified, insulin-sensitizing and anti-inflammatory protein released by adipocytes, which is paradoxically reduced in obesity. It suppresses endothelial activation. Physiological insulin resistance occurs in normal pregnancy and is exaggerated in women with preeclampsia (PE), together with enhanced inflammatory and endothelial activation. Women with increased body mass index (BMI) and insulin resistance are predisposed to PE. We hypothesized that adiponectin concentrations are reduced in normal pregnancy compared with postpartum values and further reduced in women with PE. Fifteen women with PE and 30 control subjects with similar first trimester BMI had adiponectin concentrations measured in the third trimester; postpartum measurements were repeated in 16 control subjects. Adiponectin concentration in healthy pregnant women correlated inversely with early pregnancy BMI (r =−0.47, P =0.01) and fasting insulin concentrations (r =−0.58, P =0.001). However, adiponectin concentrations did not differ significantly in pregnancy and postpartum samples (mean change, −0.15 &mgr;g/mL; 95% CI, −2.28 to 1.98, P =0.88). Plasma adiponectin concentrations were markedly elevated (P =0.01) in women with PE (mean, 21.6; SD, 8.18 &mgr;g/mL) compared with control subjects (mean, 14.7; SD, 7.06 &mgr;g/mL). Moreover, in PE, adiponectin concentrations did not correlate with first trimester BMI or insulin or with serum urate or creatinine concentrations or urinary protein levels. We conclude that plasma adiponectin concentrations are not elevated in normal human pregnancy and paradoxically elevated (by 47%) in women with PE. This may be secondary to exaggerated nonspecific adipocyte lipolysis or as a physiological response to enhance fat utilization and attenuate endothelial damage. Future studies should determine whether adiponectin concentrations help improve prediction of PE.

RE: nab-Paclitaxel Plus Gemcitabine for Metastatic Pancreatic Cancer: Long-Term Survival From a Phase III Trial.

We read with interest the article by Goldstein and colleagues that reports the long-term results of the large phase III randomized trial (IMPACT) of nab-paclitaxel plus gemcitabine or gemcitabine alone in patients with metastatic pancreatic cancer, extending support for the superior efficacy of this combination therapy (1). They reported that the presence of a systemic inflammatory response, as evidenced by an elevated neutrophil lymphocyte ratio (NLR), effectively stratified survival independent of the trial treatment. A pooled treatment analysis demonstrated that patients with an NLR of 5 or less had a statistically significantly prolonged survival compared with patients with an NLR of more than 5 (median = 9.1 vs 5.0 months, P < .001). In the nab-Paclitaxel plus gemcitabine arm there was a statistically significantly longer overall survival vs the gemcitabine arm alone in patients with an NLR of 5 or less (P < .001). Furthermore, when there was evidence of a raised systemic inflammatory response, a trend was evident favoring prolonged survival in the nab-paclitaxel plus gemcitabine arm vs the gemcitabine alone group (P = .079). These results confirm our previous observations in patients with pancreatic adenocarcinoma, that an elevated NLR is an important independent prognostic factor (2). However, there is good evidence that assessment of the systemic inflammatory response using acute phase proteins, in particular C-reactive protein (CRP) and albumin (Glasgow Prognostic Score [GPS]) has superior prognostic value in a variety of common solid tumors (3), including pancreatic cancer both in resectable and nonresectable forms (2). Therefore, it is clear that even in such a poor-prognosis tumor as pancreatic cancer outcomes can be stratified according to the systemic inflammatory response. This new knowledge offers the possibility for simple and effective stratification for patients with this difficult-to-treat cancer. For heterogeneous cancers, in particular pancreatic cancer, a stratified medicine approach offers potential to target an individual’s cancer with the right treatment for the right patient (4). This strategy could improve overall outcomes and quality of life for patients by minimizing unnecessary side effects arising from ineffective therapies. However, as demonstrated in the present study, the concept of stratification should not be limited to tumoror gene-centric aspects but extended to consider patient or host aspects including the burden of the systemic inflammatory response. Moreover, beyond stratification there is also an opportunity for therapeutic targeting of the systemic inflammatory response. Given the role of JAK-STAT signaling in the inflammatory responses of patients with pancreatic cancer (5), it is of interest that a recent randomized phase II trial of the JAK1/JAK2 inhibitor ruxolitinib combined with capecitabine in patients with metastatic pancreatic cancer revealed a statistically significantly prolonged survival for those patients who were administered ruxolitinib with coexisting evidence of an elevated systemic inflammatory response, as measured by CRP and/or the modified GPS (6). It is also of interest that nab-paclitaxel itself has potential to alter the tumor stroma and immune environment (7). In summary, the work of Goldstein and colleagues (1) confirms the prognostic value of the systemic inflammatory response in patients with metastatic pancreatic cancer. Furthermore, it heralds a new era in which the systemic inflammatory response becomes a legitimate target for treatment of these patients.

MicroRNA Molecular Profiles Associated with Diagnosis, Clinicopathologic Criteria, and Overall Survival in Patients with Resectable Pancreatic Ductal Adenocarcinoma

Purpose: MicroRNAs (miRNA) have potential as diagnostic and prognostic biomarkers and as therapeutic targets in cancer. We sought to establish the relationship between miRNA expression and clinicopathologic parameters, including prognosis, in pancreatic ductal adenocarcinoma (PDAC). Experimental Design: Global miRNA microarray expression profiling of prospectively collected fresh-frozen PDAC tissue was done on an initial test cohort of 48 patients, who had undergone pancreaticoduodenectomy between 2003 and 2008 at a single institution. We evaluated association with tumor stage, lymph node status, and site of recurrence, in addition to overall survival, using Cox regression multivariate analysis. Validation of selected potentially prognostic miRNAs was done in a separate cohort of 24 patients. Results: miRNA profiling identified expression signatures associated with PDAC, lymph node involvement, high tumor grade, and 20 miRNAs were associated with overall survival. In the initial cohort of 48 PDAC patients, high expression of miR-21 (HR = 3.22, 95% CI: 1.21–8.58) and reduced expression of miR-34a (HR = 0.15, 95% CI: 0.06–0.37) and miR-30d (HR = 0.30, 95% CI: 0.12–0.79) were associated with poor overall survival following resection independent of clinical covariates. In a further validation set of 24 patients, miR-21 and miR-34a expression again significantly correlated with overall survival (P = 0.031 and P = 0.001). Conclusion: Expression patterns of miRNAs are significantly altered in PDAC. Aberrant expression of a number of miRNAs was independently associated with reduced survival, including overexpression of miR-21 and underexpression of miR-34a. Summary: miRNA expression profiles for resected PDAC were examined to identify potentially prognostic miRNAs. miRNA microarray analysis identified statistically unique profiles, which could discriminate PDAC from paired nonmalignant pancreatic tissues as well as molecular signatures that differ according to pathologic features. miRNA expression profiles correlated with overall survival of PDAC following resection, indicating that miRNAs provide prognostic utility. Clin Cancer Res; 18(2); 534–45. ©2011 AACR.

Evaluation of an inflammation-based prognostic score in patients with inoperable pancreatic cancer.

Background/Aims: Patients with pancreatic cancer have one of the poorest survival rates and selection of patients for active treatment remains problematical. The present study assesses the value of an inflammation-based score (Glasgow Prognostic Score, GPS) in patients with inoperable pancreatic cancer. Methods: The GPS was constructed as follows: patients with both an elevated C-reactive protein (>10 mg/l) and hypoalbuminaemia (<35 g/l) were allocated a score of 2. Patients in whom only 1 or none of these biochemical abnormalities was present were allocated a score of 1 or 0, respectively. Results: One hundred and eighty-seven patients were studied and 49 (26%) underwent an operative palliative bypass procedure. At the end of follow-up, 181 (97%) patients died, 17% of patients were alive at 12 months. On univariate analysis, age (p < 0.01), TNM stage (p < 0.001) and the GPS (p < 0.001) were significant predictors of survival. On multivariate survival analysis, stratified for bypass procedure, age (hazard ratio 1.53, 95%CI 1.12–2.10, p = 0.008), TNM stage (hazard ratio 1.70, 95%CI 1.33–2.18, p < 0.001) and the GPS (hazard ratio 1.72, 95%CI 1.40–2.11, p < 0.001) remained independent significant predictors of survival. Conclusion: At diagnosis, the presence of a systemic inflammatory response (as measured by the GPS) appears to be a useful indicator of poor outcome, independent of TNM stage, in patients with inoperable pancreatic cancer.

Positive Mobilization Margins Alone Do Not Influence Survival Following Pancreatico-Duodenectomy for Pancreatic Ductal Adenocarcinoma

Objective:To determine the prognostic influence of residual tumor at or within 1 mm of the mobilization margins (R1Mobilization) compared with transection margins (R1Transection) following pancreaticoduodenectomy for pancreatic ductal adenocarcinoma (PDAC). Background:The prognostic strength of R1 status increases with frequency of margin positivity and is enhanced by protocol driven pathology reporting. Currently, margins are treated uniformly with tumor at or close to any margin considered of equal prognostic significance. The resection involves a mobilization phase freeing the posterior margin and anterior surface then a transection phase requiring lympho-vascular division forming the medial resection and pancreatic transection margin. The comparative assessment of the relative importance of tumor involvement of these different margins has not previously been investigated. Methods:Retrospective analysis of 148 consecutive resections for PDAC from 1996–2007 was performed. The individual (pancreatic transection, medial, posterior, and anterior surface) margins were separately identified and analyzed by a senior pathologist. An R1 resection was defined as microscopic evidence of tumor ≤1 mm from a resection margin. R1Mobilization tumor extension included both R1Anterior and R1Posterior cases; while R1Transection included pancreatic neck/body transection, R1Medial and adjacent transection margins. Results:R1 status was confirmed in 109 patients (74%). The medial (46%) and posterior (44%) margins were most commonly involved. R1 status was found to an independent predictor of poor outcome (P < 0.001). R1Mobilization involvement only (n = 48) was associated with a significantly longer median survival of 18.9 months (95% CI, 13.7–24.8) versus 11.1 months (95% CI, 7.1–15.0) for those with R1Transection tumor involvement (n = 61) (P < 0.001). There was no significant difference in the survival of the R1Mobilization compared with R0 group (P = 0.52). Conclusions:Following pancreaticoduodenectomy for PDAC, involvement of the transection margins in contrast to mobilization margins defines a group whose outcome is significantly worse. This may impact upon the allocation of adjuvant therapy within the setting of randomized controlled trials.

Systemic inflammatory response predicts outcome in patients undergoing resection for ductal adenocarcinoma head of pancreas.

The aim of the present study was to examine the relationship between the clinicopathological status, the pre- and postoperative systemic inflammatory response and survival in patients undergoing potentially curative resection for ductal adenocarcinoma of the head of the pancreas. Patients (n=65) who underwent resection of ductal adenocarcinoma of the head of pancreas between 1993 and 2001, and had pre- and postoperative measurements of C-reactive protein, were included in the study. The majority of patients had stage III disease (International Union Against Cancer Criteria, IUCC), positive circumferential margin involvement (R1), tumour size greater than 25 mm with perineural and lymph node invasion and died within the follow-up period. On multivariate analysis, tumour size (hazard ratio (HR) 2.10, 95% confidence interval (CI) 1.20–3.68, P=0.009), vascular invasion (HR 2.58, 95% CI 1.48–4.50, P<0.001) and postoperative C-reactive protein (HR 2.00, 95% CI 1.14–3.52, P=0.015) retained independent significance. Those patients with a postoperative C-reactive protein ⩽10 mg l−1 had a median survival of 21.5 months compared with 8.4 months in those patients with a C-reactive protein >10 mg l−1 (P<0.001). The results of the present study indicate that, in patients who have undergone potentially curative resection for ductal adenocarcinoma of the head of pancreas, the presence of a systemic inflammatory response predicts poor outcome.

CXCR2 Inhibition Profoundly Suppresses Metastases and Augments Immunotherapy in Pancreatic Ductal Adenocarcinoma.

Summary CXCR2 has been suggested to have both tumor-promoting and tumor-suppressive properties. Here we show that CXCR2 signaling is upregulated in human pancreatic cancer, predominantly in neutrophil/myeloid-derived suppressor cells, but rarely in tumor cells. Genetic ablation or inhibition of CXCR2 abrogated metastasis, but only inhibition slowed tumorigenesis. Depletion of neutrophils/myeloid-derived suppressor cells also suppressed metastasis suggesting a key role for CXCR2 in establishing and maintaining the metastatic niche. Importantly, loss or inhibition of CXCR2 improved T cell entry, and combined inhibition of CXCR2 and PD1 in mice with established disease significantly extended survival. We show that CXCR2 signaling in the myeloid compartment can promote pancreatic tumorigenesis and is required for pancreatic cancer metastasis, making it an excellent therapeutic target.