High baseline soluble urokinase plasminogen activator receptor (suPAR) serum levels indicate adverse outcome after resection of pancreatic adenocarcinoma

Surgical resection represents the only potentially curative therapy for patients with pancreatic adenocarcinoma (PDAC), an aggressive malignancy with a very limited 5-year survival rate. However, even after complete tumor resection, many patients are still facing an unfavorable prognosis underlining the need for better preoperative stratification algorithms. Here, we explored the role of the secreted glycoprotein soluble urokinase plasminogen activator receptor (suPAR) as a novel circulating biomarker for patients undergoing resection of PDAC. Serum levels of suPAR were measured by enzyme-linked immunosorbent assay (ELISA) in an exploratory as well as a validation cohort comprising a total of 127 PDAC patients and 75 healthy controls. Correlating with a cytoplasmic immunohistochemical expression of uPAR in PDAC tumor cells, serum levels of suPAR were significantly elevated in PDAC patients compared to healthy controls and patient with PDAC precursor lesions. Importantly, patients with high preoperative suPAR levels above a calculated cutoff value of 5.956 ng/ml showed a significantly reduced overall survival after tumor resection. The prognostic role of suPAR was further corroborated by uni- and multivariate Cox-regression analyses including parameters of systemic inflammation, liver and kidney function as well as clinico-pathological patients’ characteristics. Moreover, high baseline suPAR levels identified those patients particularly susceptible to acute kidney injury and surgical complications after surgery. In conclusion, our data suggest that circulating suPAR represents a novel prognostic marker in PDAC patients undergoing tumor resection that might be a useful addition to existing preoperative stratification algorithms for identifying patients that particularly benefit from extended tumor resection.

The Outcome of Ex Vivo TIL Expansion Is Highly Influenced by Spatial Heterogeneity of the Tumor T-Cell Repertoire and Differences in Intrinsic In Vitro Growth Capacity between T-Cell Clones

PURPOSE

During our efforts to develop tumor-infiltrating lymphocyte (TIL) therapy to counter the devastating recurrence rate in patients with primary resectable pancreatic ductal adenocarcinoma (PDA), we found that PDA TILs can readily be expanded in vitro and that the majority of resulting TIL cultures show reactivity against the autologous tumor. However, the fraction of tumor-reactive T cells is low. We investigated to which extent this was related to the in vitro expansion.

EXPERIMENTAL DESIGN

We compared the clonal composition of TIL preparations before and after in vitro expansion using T-cell receptor (TCR) deep sequencing. Our findings for PDA were benchmarked to experiments with melanoma TILs.

RESULTS

We found that the TIL TCR repertoire changes dramatically during in vitro expansion, leading to loss of tumor- dominant T-cell clones and overgrowth by newly emerging T-cell clones that are barely detectable in the tumor. These changes are primarily driven by differences in the intrinsic in vitro expansion capacity of T-cell clones. Single-cell experiments showed an association between poor proliferative capacity and expression of markers related to antigen experience and dysfunction. Furthermore, we found that spatial heterogeneity of the TIL repertoire resulted in TCR repertoires that are greatly divergent between TIL cultures derived from distant tumor samples of the same patient.

CONCLUSIONS

Culture-induced changes in clonal composition are likely to affect tumor reactivity of TIL preparations. TCR deep sequencing provides important insights into the factors that govern the outcome of in vitro TIL expansion and thereby a path toward optimization of the production of TIL preparations with high therapeutic efficacy.See related commentary by Lozano-Rabella and Gros, p. 4177.

Actinin-4 splice variant - a complementary diagnostic and prognostic marker of pancreatic neuroendocrine neoplasms

Introduction: For pathological diagnosis of pancreatic neuroendocrine neoplasms (pNENs) the routinely used immunohistochemical markers are chromogranin A (CgA) and synaptophysin (Syn). Their ability as prognostic markers is not well established. A splice variant of actinin-4 (Actn-4sv) was recently found to be an excellent biomarker of neuroendocrine neoplasms of the lung. We aimed to investigate the expression of Actn-4sv in pNENs and evaluate its quality as a biomarker of pNENs.

Methods: Paraffin-embedded and frozen tissues specimens from 122 pNENs were analyzed. Western blots were performed to prove and compare the relative amount of Actn-4sv expression in pNENs tissue homogenates. For comparison pancreatic ductal adenocarcinoma (PDAC) and normal pancreatic tissues were analyzed in parallel. Immunohistochemistry (IHC) of paraffin sections of pNENs for Actn-4sv were performed and compared to the classic neuroendocrine markers CgA and Syn. Correlations were calculated between the staining intensity and distribution of Actn-4sv and staging, grading and afflicted lymph nodes respectively.

Results: Actn-4sv was expressed in 88.5% (108/122) of pNENs, but not in normal pancreatic tissues (0/14) or PDAC (0/14). Compared to CgA and Syn, Actn-4sv was not detectable in islet cells of the normal pancreas. Staining intensity of Actn-4sv on pNENs negatively correlated to the histological grading (Spearman r=-0.4990, p<0.0001) and staging (r = -0.2581, p = 0.0041) but no correlation to afflicted lymph nodes was found. A significantly better overall survival was observed for pNEN patients with higher expression of Actn-4sv (hazard ratio 2.7; log-rank test p= 0.0349).

Conclusions: The expression of Actn-4sv may be an important prognostic factor for patients with pNENs. Its expression correlates with the grading and staging of the tumors.

Surgical resection for duodenal neuroendocrine neoplasia: Outcome, prognostic factors and risk of metastases

BACKGROUND

Clinical management of duodenal neuroendocrine neoplasms (dNEN) is controversial. The aim of this study was to assess the outcome of surgical management and to identify risk factors for metastatic disease.

METHODS

Patients undergoing surgery for dNEN were retrospectively analysed. Clinicopathologic features, perioperative outcome and survival were assessed. A literature review with focus on risk factors for metastatic disease was additionally performed.

RESULTS

24 patients were identified. Out of 22 patients presenting with their primary tumour, 20 patients underwent curative resection and 18 patients received curative resection with systematic lymphadenectomy. 17 patients underwent formal oncological resection. Surgical mortality was 1 out of 24 patients. The 5-year overall survival rate was 67% in the entire cohort, 71% in patients undergoing resection for their primary tumour, 72% for patients undergoing curative resection with systematic lymphadenectomy, 75% for pN0 and 70% for pN1 tumours. Lymph node metastases were identified in 15 patients undergoing systematic lymphadenectomy, including 9 of 14 patients with tumours smaller than 2 cm, and 6 of 10 patients with G1 tumours. Literature review confirmed a high risk of metastases in small (58%) or G1 (24%) tumours. Tumour grade and angioinvasion were significantly associated with overall and disease-free survival.

CONCLUSION

Even well differentiated or small dNEN harbour a considerable risk of metastases. These data challenge the concepts of surveillance, local resection and endoscopic management for dNEN based on size and grading. Angioinvasion was identified as a strong negative predictor of overall and disease-free survival in dNEN.

Effects of neoadjuvant FOLFIRINOX and gemcitabine-based chemotherapy on cancer cell survival and death in patients with pancreatic ductal adenocarcinoma

Background: The progression and response to systemic treatment of cancer is substantially dependent on the balance between cancer cell death (apoptosis and necroptosis) and cancer cell survival (autophagy). Although well characterized in experimental systems, the status of cancer cell survival and cell death in human pancreatic ductal adenocarcinoma (PDAC), especially in response to chemotherapy and different types of chemotherapy is poorly described.

Results: The median (95% confidence interval) survival was 31.6 (24.5–44.5) months after FOLFIRINOX versus 15.8 (2.0–20.5) months after gemcitabine-based therapy (p = 0.039). PDAC tissue autophagy was reduced compared to normal pancreata based on reduced BECLIN-1 expression and LC3-Lamp-2 colocalization, whilst necroptosis (RIP-1) was increased. Neoadjuvant therapy was associated with further reduced autophagy based on p62/SQSTM-1 accumulation, and increased necroptosis (RIP3 and pMLKL) and apoptosis (BAX, cleaved CASPASE-9 and CASPASE-3) markers, increased nuclear p65 (NF-κB) and extracellular HMGB1 expression, with greater CD8⁺ lymphocyte infiltration. Survival was associated with reduced autophagy and increased apoptosis. Necroptosis (RIP-3, pMLKL) and apoptosis (BAX and cleaved CASPASE-9) markers were higher after FOLFIRINOX than gemcitabine-based treatment.

Patients and methods: Cancer cell autophagy, apoptosis, and necroptosis marker expression was compared in pancreatic tissue samples from 51 subjects, comprising four groups: (1) surgical resection for PDAC after FOLFIRINOX (n = 11), or (2) after gemcitabine-based (n = 14) neoadjuvant therapy, (3) patients undergoing PDAC resection without prior chemotherapy (n = 13), and (4) normal pancreata from 13 organ donors. Marker expression was undertaken using semi-automated immunofluorescence-FACS-like analysis, defining PDAC cells by CK-7⁺ expression.

Abstract C61: Dysregulation of HNF1B/Clusterin axis enhances disease progression in a highly aggressive subset of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy and is largely refractory to available treatments with heterogenous chemotherapeutic response in subsets of patients. Identifying key pathways associated with disease aggressiveness and therapeutic resistance may characterize candidate targets to improve patient outcome. We used a strategy of examining the molecular subset of PDAC patients with worst survival to understand the underlying mechanisms of disease progression and to identify candidate molecular targets with potential therapeutic significance. Non-negative matrix factorization (NMF) clustering using gene expression profile revealed three patient subsets. A 142-gene signature specific to the subset with the worst patient survival predicted prognosis and stratified patients in two clusters in a test (N=126) and validation (N=176) cohorts with significantly different survival. Gene-network and pathway analysis of the 142-gene signature revealed dysregulation of hepatocyte nuclear factor 1-B (HNF1B)/Clusterin (CLU) axis in the highly aggressive patient subset. HNF1B positively regulated CLU and a lower expression of HNF1B and CLU was associated with poor patient survival. Mechanistic and functional analyses revealed that CLU inhibits proliferation, migration, invasion, and 3D spheroid growth and epithelial-to-mesenchymal transition in pancreatic cancer cells. Furthermore, CLU enhanced sensitivity of pancreatic cancer cells, representing the aggressive patient subset, to the chemotherapeutic drug gemcitabine. Taken together, targeting HNF1B/CLU axis may attenuate disease progression with potential therapeutic implication in a subset of pancreatic cancer.

Citation Format: Shouhui Yang, Wei Tang, Peijun He, Limin Wang, Jochen Gaedcke, B. Michael Ghadim, Philipp Ströbel, Azadeh Azizian, Matthias M. Gaida, Frank Bergmann, H. Richard Alexander, Nader Hanna, S. Perwez Hussain. Dysregulation of HNF1B/Clusterin axis enhances disease progression in a highly aggressive subset of pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2019 Sept 6-9; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2019;79(24 Suppl):Abstract nr C61.

C-reactive protein (CRP) promotes malignant properties in pancreatic neuroendocrine neoplasms

OBJECTIVE

Elevated pre-operative C-reactive protein (CRP) serum values have been reported to be associated with poor overall survival for patients with pancreatic neuroendocrine neoplasms (pNEN). The aim of this study was to identify mechanisms linking CRP to poor prognosis in pNEN.

METHODS

The malignant properties of pNENs were investigated using the human pNEN cell-lines BON1 and QGP1 exposed to CRP or IL-6. Analyses were performed by ELISA, Western blot, flow cytometry and immunocytochemistry as well as invasion and proliferation assays. To compare cytokine profiles and CRP levels, 76 serum samples of pNEN patients were analyzed using Luminex technology. In parallel, the expression of CRP and growth signaling pathway proteins was assessed on cell lines and paraffin-embedded primary pNEN.

RESULTS

In BON1 and QGP1 cells, inflammation (exposure to IL-6) significantly upregulated CRP expression and secretion as well as migratory properties. CRP stimulation of BON1 cells increased IL-6 secretion and invasion. This was accompanied by activation/phosphorylation of the ERK, AKT and/or STAT3 pathways. Although known CRP receptors - CD16, CD32 and CD64 - were not detected on BON1 cells, CRP uptake of pNEN cells was shown after CRP exposure. In patients, increased pre-operative CRP levels (≥5 mg/L) were associated with significantly higher serum levels of IL-6 and G-CSF, as well as with an increased CRP expression and ERK/AKT/STAT3 phosphorylation in pNEN tissue.

CONCLUSION

The malignant properties of pNEN cells can be stimulated by CRP and IL-6 promoting ERK/AKT/STAT pathways activation as well as invasion, thus linking systemic inflammation and poor prognosis.

Systematic Generation of Patient-Derived Tumor Models in Pancreatic Cancer

In highly aggressive malignancies like pancreatic cancer (PC), patient-derived tumor models can serve as disease-relevant models to understand disease-related biology as well as to guide clinical decision-making. In this study, we describe a two-step protocol allowing systematic establishment of patient-derived primary cultures from PC patient tumors. Initial xenotransplantation of surgically resected patient tumors (n = 134) into immunodeficient mice allows for efficient in vivo expansion of vital tumor cells and successful tumor expansion in 38% of patient tumors (51/134). Expansion xenografts closely recapitulate the histoarchitecture of their matching patients' primary tumors. Digestion of xenograft tumors and subsequent in vitro cultivation resulted in the successful generation of semi-adherent PC cultures of pure epithelial cell origin in 43.1% of the cases. The established primary cultures include diverse pathological types of PC: Pancreatic ductal adenocarcinoma (86.3%, 19/22), adenosquamous carcinoma (9.1%, 2/22) and ductal adenocarcinoma with oncocytic IPMN (4.5%, 1/22). We here provide a protocol to establish quality-controlled PC patient-derived primary cell cultures from heterogeneous PC patient tumors. In vitro preclinical models provide the basis for the identification and preclinical assessment of novel therapeutic opportunities targeting pancreatic cancer.

Efficient Pictet-Spengler Bioconjugation with N-Substituted Pyrrolyl Alanine Derivatives

We discovered N-pyrrolyl alanine derivatives as efficient reagents for the fast and selective Pictet-Spengler reaction with aldehyde-containing biomolecules. Other aldehyde-labeling methods described so far have several drawbacks, like hydrolytic instability, slow reaction kinetics or not readily available labeling reagents. Pictet-Spengler cyclizations of pyrrolyl 2-ethylamine substituted at the pyrrole nitrogen are significantly faster than with analogues substituted at the α- and β- position. Functionalized N-pyrrolyl alanine derivatives can be synthesized in only 2-3 steps from commercially available materials. The small size of the reagent, the high reaction rate, and the easy synthesis make pyrrolyl alanine Pictet-Spengler (PAPS) an attractive choice for bioconjugation reactions. PAPS was shown as an efficient strategy for the site-selective biotinylation of an antibody as well as for the condensation of nucleic-acid derivatives, demonstrating the versatility of this reagent.

[Spindle and giant cell type undifferentiated carcinoma of the distal bile duct: a case report]

Undifferentiated carcinoma of the biliary tract is rare and more frequently occurs in the gall bladder than in the extrahepatic bile ducts. We report on an extremely rare case of a spindle and giant cell type undifferentiated carcinoma of the distal bile duct. In the presented tumor, atypical glands and single-cell clusters arising from the bile duct epithelium gradually transitioned into a predominantly sarcomatoid architecture, which constituted more than 98 % of the whole tumor volume. Focally, osteoclast-like giant cells were intermixed with the spindle cells. The tumor showed a high proliferation activity (Ki-67) and was demonstrated to harbor mutations in the genes for cyclin D3 (CCND3), fibroblast growth factor receptor 4 (FGFR4), neurofibromin 1 (NF1) and NOTCH3, as assessed by next-generation sequencing analysis. The presented case underscores the relevance of this tumor entity beyond the pancreas and gall bladder and emphasizes the indispensable combination of morphology and immunohistochemistry regarding the diagnostic process.

Further Evidence of von Willebrand Factor Involvement in Thrombotic Thrombocytopenia Purpura

Fourteen patients diagnosed as having thrombotic thrombocytopenia purpura (TTP) were studied. Those who survived have been followed during a 1 to 7 year period. The clinical diagnosis was based on changing neurological findings, thrombocytopenia and evidence of microangiopathic hemolytic anemia. Laboratory tests included the determination of von Willebrand factor antigen (VWF:Ag), ristocetin cofactor (RiCof) and the electrophoretic mobility of von Willebrand factor (CIE VWF:Ag). The ratio of RiCof to VWF:Ag was then calculated. Control individuals included healthy subjects and patients with thrombocytopenia of several etiologies. Statistical differences between the values of RiCof, the ratio of RiCof : VWF: Ag and the CIE of VWF: Ag were found for samples comparing active disease and remission phase. The recovery from thrombocytopenia paralleled the correction of abnormal parameters. Similarly, significant differences were found when above parameters were compared between thrombocytopenia of TTP with other thrombocytopenic states. We suggest that these abnormal tests could be useful in distinguishing TTP from other disorders, and may have prognostic significance in patients already diagnosed as having TTP.

NRG1 Fusions in KRAS Wild-Type Pancreatic Cancer

We used whole-genome and transcriptome sequencing to identify clinically actionable genomic alterations in young adults with pancreatic ductal adenocarcinoma (PDAC). Molecular characterization of 17 patients with PDAC enrolled in a precision oncology program revealed gene fusions amenable to pharmacologic inhibition by small-molecule tyrosine kinase inhibitors in all patients with KRAS wild-type (KRAS^WT) tumors (4 of 17). These alterations included recurrent NRG1 rearrangements predicted to drive PDAC development through aberrant ERBB receptor-mediated signaling, and pharmacologic ERBB inhibition resulted in clinical improvement and remission of liver metastases in 2 patients with NRG1-rearranged tumors that had proved resistant to standard treatment. Our findings demonstrate that systematic screening of KRAS^WT tumors for oncogenic fusion genes will substantially improve the therapeutic prospects for a sizeable fraction of patients with PDAC.Significance: Advanced PDAC is a malignancy with few treatment options that lacks molecular mechanism-based therapies. Our study uncovers recurrent gene rearrangements such as NRG1 fusions as disease-driving events in KRAS^wt tumors, thereby providing novel insights into oncogenic signaling and new therapeutic options in this entity. Cancer Discov; 8(9); 1087-95. ©2018 AACR.This article is highlighted in the In This Issue feature, p. 1047.

Validation of at least 1 mm as cut-off for resection margins for pancreatic adenocarcinoma of the body and tail

BACKGROUND

The definition of resection margin (R) status in pancreatic cancer is under debate. Although a margin of at least 1 mm is an independent predictor of survival after resection for pancreatic head cancer, its relevance to pancreatic body and tail cancers remains unclear. This study aimed to validate R status based on a 1-mm tumour-free margin as a prognostic factor for resected adenocarcinoma involving the pancreatic body and tail.

METHODS

Patients who underwent distal or total pancreatectomy for adenocarcinomas of the pancreatic body and tail between January 2006 and December 2014 were identified from a prospective database. Resection margins were evaluated using a predefined cut-off of 1 mm. Rates of R0, R1 with invasion within 1 mm of the margin (R1 less than 1 mm), and R1 with direct invasion of the resection margin (R1 direct) were determined, and overall survival in each group assessed by Kaplan-Meier analysis. Univariable and multivariable Cox regression analyses were performed to identify predictors of survival.

RESULTS

R0 resection was achieved in 107 (23·5 per cent) and R1 in 348 (76·5 per cent) of 455 patients. Among R1 resections, invasion within 1 mm of the margin was found in 104 (22·9 per cent) and direct invasion in 244 (53·6 per cent). The R0 rate was 28·9 per cent after distal and 18·6 per cent after total pancreatectomy. In the total cohort, median survival times for patients with R0, R1 (less than 1 mm) and R1 (direct) status were 62·4, 24·6 and 17·2 months respectively, with 5-year survival rates of 52·6, 16·8 and 13·0 per cent (P < 0·001). In patients who received adjuvant chemotherapy, respective median survival times were 68·6, 32·8 and 21·4 months, with 5-year survival rates of 56, 22 and 16·0 per cent (P < 0·001). In multivariable analysis, R status was independently associated with survival.

CONCLUSION

A cut-off of at least 1 mm for evaluation of resection margins is an independent determinant of survival after resection of adenocarcinomas of the pancreatic body and tail.

Succession of transiently active tumor-initiating cell clones in human pancreatic cancer xenografts

Although tumor-initiating cell (TIC) self-renewal has been postulated to be essential in progression and metastasis formation of human pancreatic adenocarcinoma (PDAC), clonal dynamics of TICs within PDAC tumors are yet unknown. Here, we show that long-term progression of PDAC in serial xenotransplantation is driven by a succession of transiently active TICs producing tumor cells in temporally restricted bursts. Clonal tracking of individual, genetically marked TICs revealed that individual tumors are generated by distinct sets of TICs with very little overlap between subsequent xenograft generations. An unexpected functional and phenotypic plasticity of pancreatic TICs in vivo underlies the recruitment of inactive TIC clones in serial xenografts. The observed clonal succession of TIC activity in serial xenotransplantation is in stark contrast to the continuous activity of limited numbers of self-renewing TICs within a fixed cellular hierarchy observed in other epithelial cancers and emphasizes the need to target TIC activation, rather than a fixed TIC population, in PDAC.

The expression of genes contributing to pancreatic adenocarcinoma progression is influenced by the respective environment

Pancreatic adenocarcinoma is a highly aggressive malignancy with dismal prognosis and limited curative options. We investigated the influence of organ environments on gene expression in RNU rats by orthotopic and intraportal infusion of Suit2-007luc cells into the pancreas, liver and lung respectively. Tumor tissues from these sites were analyzed by chip array and histopathology. Generated data was analyzed by Chipster and Ingenuity Pathway Analysis (±1.5 expression fold change and p<0.05). Further analysis of functional annotations derived from IPA, was based on selected genes with significant modulation of expression. Comparison of groups was performed by creating ratios from the mean expression values derived from pancreas and respective in vitro values, whereas those from liver and lung were related to pancreas, respectively. Genes of interest from three functional annotations for respective organs were identified by exclusion-overlap analyses. From the resulting six genes, transglutaminase2 (TGM2) was further investigated by various assays. Its knockdown with siRNA induced dose dependent inhibitory and stimulatory effects on cell proliferation and cell migration, respectively. DNA fragmentation indicated apoptotic cell death in response to TGM2 knockdown. Cell cycle analysis by FACS showed that TGM2 knockdown induced G1/S blockade. Therefore, TGM2 and its associated genes may be promising therapeutic targets.

Diagnose angeborener Störungen der Thrombozytenfunktion

Angeborene Störungen der Thrombozytenfunktion sind eine heterogene Gruppe von Erkrankungen, die oft erst bei Auftreten von Blutungen erkannt werden. Im klinischen Bereich haben sich nur wenige Methoden zur Diagnose und Klassifizierung von angeborenen Thrombozytenfunktionsstörungen bewährt. Für eine rationelle Diagnostik ist ein stufenweises Vorgehen empfehlenswert. Anamnese und klinische Untersuchung sind Grundvoraussetzungen. Das von-Willebrand-Syndrom und andere plasmatische Gerinnungsstörungen sollten vor einer spezifischen Thrombozytenfunktionsdiagnostik immer ausgeschlossen werden. Die Bestimmung von Zahl, Größe, Volumen (MPV) und Morphologie der Thrombozyten erlauben Rückschlüsse auf die zu Grunde liegende Störung.

Die PFA-100®-Verschlusszeit eignet sich als Screening zum Ausschluss schwerer Thrombozytenfunktionsstörungen. Die Aggrego metrie ermöglicht die Untersuchung zahlreicher Aspekte der Thrombozytenfunktion. Die Durchflusszytometrie ist zur Diagnose von Thrombasthenie Glanzmann, Bernard-Soulier- Syndrom und Freisetzungsstörungen geeignet. Molekulargenetische Untersuchungen können die Verdachtsdiagnose bestätigen oder zum Nachweis nicht beschriebener Defekte verwendet werden. Hier wird die ungekürzte Version der inter -disziplinären Leitlinie* präsentiert.

Upregulation of cell cycle genes in head and neck cancer patients may be antagonized by erufosine's down regulation of cell cycle processes in OSCC cells

The TCGA database was analyzed to identify deregulation of cell cycle genes across 24 cancer types and ensuing effects on patient survival. Pan-cancer analysis showed that head and neck squamous cell carcinoma (HNSCC) ranks amongst the top four cancers showing deregulated cell cycle genes. Also, the median gene expression of all CDKs and cyclins in HNSCC patient samples was higher than that of the global gene expression. This was verified by IHC staining of CCND1 from HNSCC patients. When evaluating the quartiles with highest and lowest expression, increased CCND1/CDK6 levels had negative implication on patient survival. In search for a drug, which may antagonize this tumor profile, the potential of the alkylphosphocholine erufosine was evaluated against cell lines of the HNSCC subtype, oral squamous cell carcinoma (OSCC) using in-vitro and in-vivo assays. Erufosine inhibited growth of OSCC cell lines concentration dependently. Initial microarray findings revealed that cyclins and CDKs were down-regulated concentration dependently upon exposure to erufosine and participated in negative enrichment of cell cycle processes. These findings, indicating a pan-cdk/cyclin inhibition by erufosine, were verified at both, mRNA and protein levels. Erufosine caused a G2/M block and inhibition of colony formation. Significant tumor growth retardation was seen upon treatment with erufosine in a xenograft model. For the decreased cyclin D1 and CDK 4/6 levels found in tumor tissue, these proteins can serve as biomarker for erufosine intervention. The findings demonstrate the potential of erufosine as cell cycle inhibitor in HNSCC treatment, alone or in combination with current therapeutic agents.

Genome-wide genetic and epigenetic analyses of pancreatic acinar cell carcinomas reveal aberrations in genome stability

Pancreatic acinar cell carcinoma (ACC) is an aggressive exocrine tumor with largely unknown biology. Here, to identify potential targets for personalized treatment, we perform integrative genome-wide and epigenome-wide analyses. The results show frequently aberrant DNA methylation, abundant chromosomal amplifications and deletions, and mutational signatures suggesting defective DNA repair. In contrast to pancreatic ductal adenocarcinoma, no recurrent point mutations are detected. The tumor suppressors ID3, ARID1A, APC, and CDKN2A are frequently impaired also on the protein level and thus potentially affect ACC tumorigenesis. Consequently, this work identifies promising therapeutic targets in ACC for drugs recently approved for precision cancer therapy.

Discovery of a microbial transglutaminase enabling highly site-specific labeling of proteins

Microbial transglutaminases (MTGs) catalyze the formation of Gln–Lys isopeptide bonds and are widely used for the cross-linking of proteins and peptides in food and biotechnological applications (e.g. to improve the texture of protein-rich foods or in generating antibody-drug conjugates). Currently used MTGs have low substrate specificity, impeding their biotechnological use as enzymes that do not cross-react with nontarget substrates (i.e. as bio-orthogonal labeling systems). Here, we report the discovery of an MTG from Kutzneria albida (KalbTG), which exhibited no cross-reactivity with known MTG substrates or commonly used target proteins, such as antibodies. KalbTG was produced in Escherichia coli as soluble and active enzyme in the presence of its natural inhibitor ammonium to prevent potentially toxic cross-linking activity. The crystal structure of KalbTG revealed a conserved core similar to other MTGs but very short surface loops, making it the smallest MTG characterized to date. Ultra-dense peptide array technology involving a pool of 1.4 million unique peptides identified specific recognition motifs for KalbTG in these peptides. We determined that the motifs YRYRQ and RYESK are the best Gln and Lys substrates of KalbTG, respectively. By first reacting a bifunctionalized peptide with the more specific KalbTG and in a second step with the less specific MTG from Streptomyces mobaraensis, a successful bio-orthogonal labeling system was demonstrated. Fusing the KalbTG recognition motif to an antibody allowed for site-specific and ratio-controlled labeling using low label excess. Its site specificity, favorable kinetics, ease of use, and cost-effective production render KalbTG an attractive tool for a broad range of applications, including production of therapeutic antibody-drug conjugates.

RIP3 attenuates the pancreatic damage induced by deletion of ATG7

Invalidation of pancreatic autophagy entails pancreatic atrophy, endocrine and exocrine insufficiency and pancreatitis. The aim of this study was to investigate whether depletion of Rip3, which is involved in necroptotic signaling, may attenuate the pancreatic atrophy and pancreatitis resulting from autophagy inhibition. Autophagy and necroptosis signaling were evaluated in mice lacking expression of Rip3 in all organs and Atg7 in the pancreas. Acinar cell death, inflammation and fibrosis were evaluated by using of a compendium of immunofluorescence methods and immunoblots. Mice deficient for pancreatic Atg7 developed acute pancreatitis, which progressed to chronic pancreatitis. This phenotype reduces autophagy, increase apoptosis and necroptosis, inflammation and fibrosis, as well as premature death of the animals. Knockout of Rip3 exacerbated the apoptotic death of acinar cells, increased tissue damage, reduced macrophage infiltration and further accelerated the death of the mice with Atg7-deficient pancreas. The pancreatic degeneration induced by autophagy inhibition was exacerbated by Rip3 deletion.

Abstract 4789: A novel MIF signaling pathway drives the malignant character of pancreatic cancer by targeting NR3C2

Pancreatic cancers with aberrant expression of macrophage migration inhibitory factor (MIF) are particularly aggressive. To identify key signaling pathways that drive disease aggressiveness in tumors with high MIF expression, we analyzed the expression of coding and noncoding genes in high and low MIF-expressing tumors in multiple cohorts of pancreatic ductal adenocarcinoma (PDAC) patients. The key genes and pathways identified were linked to patient survival and were mechanistically, functionally, and clinically characterized using cell lines, a genetically engineered mouse model, and PDAC patient cohorts. Here, we report evidence of a novel MIF-driven signaling pathway that inhibits the orphan nuclear receptor NR3C2, a previously undescribed tumor suppressor that impacts aggressiveness and survival in PDAC. Mechanistically, MIF upregulated miR-301b that targeted NR3C2 and suppressed its expression. PDAC tumors expressing high levels of MIF displayed elevated levels of miR-301b and reduced levels of NR3C2. In addition, reduced levels of NR3C2 expression correlated with poorer survival in multiple independent cohorts of PDAC patients. Functional analysis showed that NR3C2 inhibited epithelial-to-mesenchymal transition and enhanced sensitivity to the gemcitabine, a chemotherapeutic drug used in PDAC standard of care. Furthermore, genetic deletion of MIF disrupted a MIF-mir-301b-NR3C2 signaling axis, reducing metastasis and prolonging survival in a genetically engineered mouse model of PDAC. Taken together, our results offer a preclinical proof of principle for candidate therapies to target a newly described MIF-miR-301b-NR3C2 signaling axis for PDAC management.

Citation Format: Shouhui Yang, Peijun He, Liming Wang, Jian Wang, Aaron Schetter, Wei Tang, Naotake Funamizu, Katsuhiko Yanaga, Tadashi Uwagawa, Abhay R. Satoskar, Jochen Gaedcke, Markus Bernhardt, B. Michael Ghadimi, Matthias M Gaida, Frank Bergmann, Jens Werner, Thomas Ried, Nader Hanna, H. Richard Alexander, S. Perwez Hussain. A novel MIF signaling pathway drives the malignant character of pancreatic cancer by targeting NR3C2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4789. doi:10.1158/1538-7445.AM2017-4789