Faculty Bibliography

BACKGROUND & AIMS/OBJECTIVE:Cigarette smoking is an established risk factor for pancreatic cancer, but there is conflicting evidence regarding the effects of alcohol consumption. The effects of cigarettes and alcohol on age of sporadic pancreatic cancer diagnosis have not been examined; we evaluated the independent and synergistic effects of lifetime cigarette smoking and alcohol consumption on age at pancreatic cancer diagnosis in the United States. METHODS:We analyzed data on cigarette smoking and alcohol consumption from the IMPAC Services, Inc Cancer Information Resource File (CIRF), collected from June 1, 1993, to December 31, 2003, for 29,239 reported, histologically confirmed cases of pancreatic adenocarcinoma. We also analyzed data on cigarette smoking and alcohol consumption for 820 histologically confirmed cases of pancreatic adenocarcinoma from the University of Michigan Pancreatic Cancer Registry (UMPCR), collected from January 2004 to October 2007. RESULTS:Current cigarette smokers were diagnosed at significantly younger ages than never smokers, according to data from the CIRF and UMPCR (8.3 and 6.3 y, respectively); the UMPCR data indicated dose effects. Past and current alcohol consumption were associated with younger age at diagnosis in both databases. Current smokers who were current drinkers were diagnosed significantly earlier (CIRF, 10.2 y; UMPCR, 8.6 y) than abstainers. Past cigarette smoking was associated modestly with younger diagnosis age. CONCLUSIONS:Cigarette smoking and alcohol consumption were associated with younger age at pancreatic cancer presentation and have a combined effect on diagnosis age. Past cigarette smoking is less influential. Smoking cessation programs could help prevent pancreatic cancer.

Th17 cells play an active role in autoimmune diseases. However, the nature of Th17 cells is poorly understood in cancer patients. We studied Th17 cells, the associated mechanisms, and clinical significance in 201 ovarian cancer patients. Tumor-infiltrating Th17 cells exhibit a polyfunctional effector T-cell phenotype, are positively associated with effector cells, and are negatively associated with tumor-infiltrating regulatory T cells. Tumor-associated macrophages promote Th17 cells through interleukin-1beta (IL-1beta), whereas tumor-infiltrating regulatory T cells inhibit Th17 cells through an adenosinergic pathway. Furthermore, through synergistic action between IL-17 and interferon-gamma, Th17 cells stimulate CXCL9 and CXCL10 production to recruit effector T cells to the tumor microenvironment. The levels of CXCL9 and CXCL10 are associated with tumor-infiltrating effector T cells. The levels of tumor-infiltrating Th17 cells and the levels of ascites IL-17 are reduced in more advanced diseases and positively predict patient outcome. Altogether, Th17 cells may contribute to protective human tumor immunity through inducing Th1-type chemokines and recruiting effector cells to the tumor microenvironment. Inhibition of Th17 cells represents a novel immune evasion mechanism. This study thus provides scientific and clinical rationale for developing novel immune-boosting strategies based on promoting the Th17 cell population in cancer patients.

Protein microarrays have been used to explore whether a humoral response to pancreatic cancer-specific tumor antigens has utility as a biomarker of pancreatic cancer. To determine if such arrays can be used to identify novel autoantibodies in the sera from pancreatic cancer patients, proteins from a pancreatic adenocarcinoma cell line (MIAPACA) were resolved by 2-D liquid-based separations, and then arrayed on nitrocellulose slides. The slides were probed with serum from a set of patients diagnosed with pancreatic cancer and compared with age- and sex-matched normal subjects. To account for patient-to-patient variability, we used a rank-based non-parametric statistical testing approach in which proteins eliciting significant differences in the humoral response in cancer compared with control samples were identified. The prediction analysis for microarrays classification algorithm was used to explore the classification power of the proteins found to be differentially expressed in cancer and control sera. The generalization error of the classification analysis was estimated using leave-one-out cross-validation. A serum diagnosis of pancreatic cancer in this set was predicted with 86.7% accuracy, with a sensitivity and specificity of 93.3 and 80%, respectively. Candidate autoantibody biomarkers identified using this approach were studied for their classification power by performing a humoral response experiment on recombinant proteins using an independent sample set of 238 serum samples. Phosphoglycerate kinase-1 and histone H4 were noted to elicit a significant differential humoral response in cancer sera compared with age- and sex-matched sera from normal patients and patients with chronic pancreatitis and diabetes. This work demonstrates the use of natural protein arrays to study the humoral response as a means to search for the potential markers of cancer in serum.

Pancreatic cancer continues to be a malignancy with few therapeutic options. The majority of patients that present for an evaluation have locally advanced or metastatic disease that is incurable by surgical approaches. Chemotherapy and radiotherapy resistance of pancreatic adenocarcinomas limits the efficacy of these therapeutic approaches. Recent evidence supports the existence of human pancreatic cancer stem cells, which appear to drive tumor initiation and progression and are particularly resistant to cell death induced by radiation or chemotherapy. Understanding the mechanisms of pancreatic cancer stem cell self-renewal and resistance to standard therapies may lead to new, more effective therapies to treat this dismal disease.

Activated T cells may express FOXP3. It is thought that FOXP3 is not a specific marker to determine regulatory T cells (Treg) in humans. Here, we examined the functional phenotype and cytokine profile of the in vitro induced FOXP3(+) T cells, primary FOXP3(+) and FOXP3(-) T cells in patients with ulcerative colitis and tumors including colon carcinoma, melanoma, hepatic carcinoma, ovarian carcinoma, pancreatic cancer, and renal cell carcinoma. We observed similar levels of suppressive capacity of primary FOXP3(+) T cells in blood, tumors, and colitic tissues. Compared with primary FOXP3(-) T cells in the same microenvironment, these primary FOXP3(+) T cells expressed minimal levels of effector cytokines, negligible amount of cytotoxic molecule granzyme B, and levels of suppressive molecules interleukin-10 and PD-1. Although the in vitro activated T cells expressed FOXP3, these induced FOXP3(+) T cells expressed high levels of multiple effector cytokines and were not functionally suppressive. The data reinforce the fact that FOXP3 remains an accurate marker to define primary Tregs in patients with cancer and autoimmune disease. We suggest that the combination of FOXP3 and cytokine profile is useful for further functionally distinguishing primary Tregs from activated conventional T cells.

Pancreatic cancer is a deadly disease characterized by late diagnosis and resistance to therapy. Much progress has been made in defining gene defects in pancreatic cancer, but a full accounting of its molecular pathogenesis remains to be provided. Here, we show that expression of the ataxia-telangiectasia group D complementing gene (ATDC), also called TRIM29, is elevated in most invasive pancreatic cancers and pancreatic cancer precursor lesions. ATDC promoted cancer cell proliferation in vitro and enhanced tumor growth and metastasis in vivo. ATDC expression correlated with elevated beta-catenin levels in pancreatic cancer, and beta-catenin function was required for ATDC's oncogenic effects. ATDC was found to stabilize beta-catenin via ATDC-induced effects on the Disheveled-2 protein, a negative regulator of glycogen synthase kinase 3beta in the Wnt/beta-catenin signaling pathway.

Pancreatic cancer is a formidable disease and early detection biomarkers are needed to make inroads into improving the outcomes in these patients. In this work, lectin antibody microarrays were utilized to detect unique glycosylation patterns of proteins from serum. Antibodies to four potential glycoprotein markers that were found in previous studies were printed on nitrocellulose coated glass slides and these microarrays were hybridized against patient serum to extract the target glycoproteins. Lectins were then used to detect different glycan structural units on the captured glycoproteins in a sandwich assay format. The biotinylated lectins used to assess differential glycosylation patterns were Aleuria aurentia lectin (AAL), Sambucus nigra bark lectin (SNA), Maackia amurensis lectin II (MAL), Lens culinaris agglutinin (LCA), and Concanavalin A (ConA). Captured glycoproteins were evaluated on the microarray in situ by on-plate digestion and direct analysis using MALDI QIT-TOF mass spectroscopy. Analysis was performed using serum from 89 normal controls, 35 chronic pancreatitis samples, 37 diabetic samples and 22 pancreatic cancer samples. We found that this method had excellent reproducibility as measured by the signal deviation of control blocks as on-slide standard and 41 pairs of pure technical replicates. It was possible to discriminate cancer from the other disease groups and normal samples with high sensitivity and specificity where the response of Alpha-1-beta glycoprotein to lectin SNA increased by 69% in the cancer sample compared to the other noncancer groups (95% confidence interval 53-86%). These data suggest that differential glycosylation patterns detected on high-throughput lectin glyco-antibody microarrays are a promising biomarker approach for the early detection of pancreatic cancer.

Emerging evidence suggests that malignant tumors are composed of a small subset of distinct cancer cells, termed "cancer stem cells" (typically less than 5% of total cancer cells based on cell surface marker expression), which have great proliferative potential, as well as more differentiated cancer cells, which have very limited proliferative potential. Data have been provided to support the existence of cancer stem cells in several different types of cancer, including human blood, brain, prostate, ovarian, melanoma, colon, and breast cancers. We have recently reported the identification of a subpopulation of pancreatic cancer cells that express the cell surface markers CD44+CD24+ESA+ (0.2-0.8% of all human pancreatic cancer cells) that function as pancreatic cancer stem cells. The CD44+CD24+ESA+ pancreatic cancer cells are highly tumorigenic and possess the stem cell-like properties of self-renewal and the ability to produce differentiated progeny. Pancreatic cancer stem cells also demonstrate upregulation of molecules important in developmental signaling pathways, including sonic hedgehog and the polycomb gene family member Bmi-1. Of clinical importance, cancer stem cells in several tumor types have shown resistance to standard therapies and may play a role in treatment failure or disease recurrence. Identification of pancreatic cancer stem cells and further elucidation of the signaling pathways that regulate their growth and survival may provide novel therapeutic approaches to treat pancreatic cancer, which is notoriously resistant to standard chemotherapy and radiation.