Multimodal mass spectrometry imaging identifies cell-type-specific metabolic and lipidomic variation in the mammalian liver

Spatial single-cell omics provides a readout of biochemical processes. It is challenging to capture the transient lipidome/metabolome from cells in a native tissue environment. We employed water gas cluster ion beam secondary ion mass spectrometry imaging ([H2O]n>28K-GCIB-SIMS) at ≤3 μm resolution using a cryogenic imaging workflow. This allowed multiple biomolecular imaging modes on the near-native-state liver at single-cell resolution. Our workflow utilizes desorption electrospray ionization (DESI) to build a reference map of metabolic heterogeneity and zonation across liver functional units at tissue level. Cryogenic dual-SIMS integrated metabolomics, lipidomics, and proteomics in the same liver lobules at single-cell level, characterizing the cellular landscape and metabolic states in different cell types. Lipids and metabolites classified liver metabolic zones, cell types and subtypes, highlighting the power of spatial multi-omics at high spatial resolution for understanding celluar and biomolecular organizations in the mammalian liver.

Angiopoietin-2 blockade suppresses growth of liver metastases from pancreatic neuroendocrine tumors by promoting T cell recruitment

Improving the management of metastasis in pancreatic neuroendocrine tumors (PanNETs) is critical, as nearly half of patients with PanNETs present with liver metastases, and this accounts for the majority of patient mortality. We identified angiopoietin-2 (ANGPT2) as one of the most upregulated angiogenic factors in RNA-Seq data from human PanNET liver metastases and found that higher ANGPT2 expression correlated with poor survival rates. Immunohistochemical staining revealed that ANGPT2 was localized to the endothelial cells of blood vessels in PanNET liver metastases. We observed an association between the upregulation of endothelial ANGPT2 and liver metastatic progression in both patients and transgenic mouse models of PanNETs. In human and mouse PanNET liver metastases, ANGPT2 upregulation coincided with poor T cell infiltration, indicative of an immunosuppressive tumor microenvironment. Notably, both pharmacologic inhibition and genetic deletion of ANGPT2 in PanNET mouse models slowed the growth of PanNET liver metastases. Furthermore, pharmacologic inhibition of ANGPT2 promoted T cell infiltration and activation in liver metastases, improving the survival of mice with metastatic PanNETs. These changes were accompanied by reduced plasma leakage and improved vascular integrity in metastases. Together, these findings suggest that ANGPT2 blockade may be an effective strategy for promoting T cell infiltration and immunostimulatory reprogramming to reduce the growth of liver metastases in PanNETs.

Vibration Controlled Transient Elastography to Evaluate Steatosis in Candidate Living Donors for Liver Transplantation

BACKGROUND

The ability of vibration controlled transient elastography (VCTE) to reliably exclude significant steatosis in living donor candidates could obviate the need for invasive liver biopsies, expedite the donor approval process, and reduce recipient wait time. We therefore aimed to determine whether VCTE controlled attenuation parameter (CAP) could be used to detect steatosis in potential living donors.

METHODS

Living donor candidates who presented for evaluation between 2016 and 2019 underwent standard donor workup, VCTE, and liver biopsy if indicated. CAP scores were compared with MRI-Fat Fraction and, when available, histologic fat fraction from liver biopsy. Receiver operating characteristic curves were used to identify cutoffs with appropriate sensitivity and specificity for screening. Statistical analysis was conducted using R (version 3.6.0).

RESULTS

Seventy-nine candidate living donors presented during the study period, of whom 71 were included in the final analysis and of whom 20 underwent liver biopsy. There was a positive correlation between MRI-Fat Fraction and CAP scores with an observed Spearman correlation coefficient of 0.424 ( P < 0.01). A CAP score of 271.5 dB/m or less was determined to have 89.8% sensitivity and 75% specificity for detecting <5% steatosis on MRI. The correlation between CAP and steatosis of available histologic samples had a Pearson correlation coefficient of 0.603 ( P = 0.005). A CAP cutoff of 276.0 dB/m demonstrated 66.7% sensitivity and 85.7% specificity for detecting <15% histopathologic steatosis and positive and negative predictive values of 71.5% and 82.7%, respectively.

CONCLUSIONS

VCTE can be integrated into living donor evaluation to accurately screen for hepatic steatosis.

A Therapeutically Targetable TAZ-TEAD2 Pathway Drives the Growth of Hepatocellular Carcinoma via ANLN and KIF23

BACKGROUND & AIMS

Despite recent progress, long-term survival remains low for hepatocellular carcinoma (HCC). The most effective HCC therapies target the tumor immune microenvironment (TIME), and there are almost no therapies that directly target tumor cells. Here, we investigated the regulation and function of tumor cell-expressed Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) in HCC.

METHODS

HCC was induced in mice by Sleeping Beauty-mediated expression of MET, CTNNB1-S45Y, or TAZ-S89A, or by diethylnitrosamine plus CCl4. Hepatocellular TAZ and YAP were deleted in floxed mice via adeno-associated virus serotype 8-mediated expression of Cre. TAZ target genes were identified from RNA sequencing, confirmed by chromatin immunoprecipitation, and evaluated in a clustered regularly interspaced short palindromic repeats interference (CRISPRi) screen. TEA domain transcription factors (TEADs), anillin (ANLN), Kif23, and programmed cell death protein ligand 1 were knocked down by guide RNAs in dead clustered regularly interspaced short palindromic repeats-associated protein 9 (dCas9) knock-in mice.

RESULTS

YAP and TAZ were up-regulated in murine and human HCC, but only deletion of TAZ consistently decreased HCC growth and mortality. Conversely, overexpression of activated TAZ was sufficient to trigger HCC. TAZ expression in HCC was regulated by cholesterol synthesis, as demonstrated by pharmacologic or genetic inhibition of 3-hydroxy-3-methylglutaryl- coenzyme A reductase (HMGCR), farnesyl pyrophosphate synthase, farnesyl-diphosphate farnesyltransferase 1 (FDFT1), or sterol regulatory element-binding protein 2 (SREBP2). TAZ- and MET/CTNNB1-S45Y-driven HCC required the expression of TEAD2 and, to a lesser extent, TEAD4. Accordingly, TEAD2 displayed the most profound effect on survival in patients with HCC. TAZ and TEAD2 promoted HCC via increased tumor cell proliferation, mediated by TAZ target genes ANLN and kinesin family member 23 (KIF23). Therapeutic targeting of HCC, using pan-TEAD inhibitors or the combination of a statin with sorafenib or anti-programmed cell death protein 1, decreased tumor growth.

CONCLUSIONS

Our results suggest the cholesterol-TAZ-TEAD2-ANLN/KIF23 pathway as a mediator of HCC proliferation and tumor cell-intrinsic therapeutic target that could be synergistically combined with TIME-targeted therapies.

Abstract 601: Serological responses to tumor-associated adducts in pancreatic cancer

The incidence of pancreatic cancer has increased over the past several decades and is now the fourth leading cause of cancer death in the USA. Only 8.5% of the patients live beyond 5 years after their initial diagnosis. This dismal survival rate is partly explained by the fact that most pancreatic cancer cases are detected late when treatment options are limited. Novel biomarkers are crucially needed. It has long been recognized that cancer cells abnormally accumulate chemical groups covalently linked to proteins, DNA and other molecules. Humoral responses to these “adducts” have not been thoroughly explored. To investigate these responses, we developed an ELISA platform for the detection of serum IgG reactive to 93 adducts, including post-translational modifications known to contribute to tumorigenesis, progression, and metastasis. Our panel also includes oxidation-related modification, advanced glycation end products, and certain co-enzymes that qualify as adducts based on their binding properties. Using this assay, we measured anti-adduct antibodies in the serum of adult healthy donors (N=24; age range 40-80) as well as patients with pancreatic cancer (N=31; age range 50-90). Importantly, all patient specimens were collected before any treatment. Reactivity to all adducts was analyzed using a random forest predictive model with 10,000 bootstrapped decision trees to distinguish between the two groups. Results revealed a distinctive anti-adduct IgG reactivity profile for pancreatic cancer patients when compared to controls. Applying feature selection using the Boruta algorithm identified a reduced set of 19 target adducts recognized by IgG that most efficiently discriminated between healthy donors and pancreatic cancer cases. All 19 adducts were confirmed as IgG targets in cancer patients using multiple unpaired t-tests (p≤0,05). Aside from their predictive value, we reasoned that the detection of adduct-specific antibodies in cancer patients reflected their accumulation in the tumor cells. To test this hypothesis, we assessed the level of two representative target adducts by immunofluorescence staining in tumor tissue compared to control adjacent non-tumoral tissue or healthy tonsil. Results unequivocally show higher levels of these two adducts in cancer cells compared to non-cancer cells. Taken together, these preliminary findings support our hypothesis of the development of anti-adduct antibodies in pancreatic cancer patients. Furthermore, the specific antibody signature detected in these patients is consistent with the abnormal presence of corresponding adducts in the transformed cells. Our findings pave the way for the development of diagnostic tests based on the detection of serum IgG specific to tumor-associated adducts.

Citation Format: Talita Aguiar, Shunya Mashiko, Poulomi Roy, Max Dietzel, Kesava Asam, Bradley Aouizerat, Jeanine Genkinger, Helen Remotti, Emmanuel Zorn. Serological responses to tumor-associated adducts in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 601.

Stable liver graft post anti-PD1 therapy as a bridge to transplantation in an adolescent with hepatocellular carcinoma

BACKGROUND

Immunotherapy, specifically immune checkpoint inhibitors (ICIs), including anti-programmed cell death 1 (anti-PD1), has recently received clinical approval for the treatment of adult hepatocellular carcinoma (HCC). However, the safety and efficacy of ICIs prior to solid organ transplant are unknown, especially in pediatrics. Safety reports are variable in adults, with some series describing subsequent allograft rejection and loss while others report successful transplants without allograft rejection.As ICIs stimulate the immune system by blocking the interaction between PD1 and the ligand-receptor pair programmed cell death-ligand 1 (PDL1), the downstream effects of T-cell activation increase the risk of graft rejection.

METHODS

Here, we present a case of an adolescent with moderately differentiated non-fibrolamellar HCC treated with pembrolizumab, an anti-PD1 therapy, who subsequently underwent successful orthotopic liver transplantation (OLT).

RESULTS

Our patient received an OLT 138 days from the last pembrolizumab dose with graft preservation. The patient has no evidence of recurrent disease or any episode of allograft rejection 48 months post OLT. Staining of tumor and normal tissues from longitudinal specimens finds PDL1 positive Kupffer cells present in normal liver and peritumoral areas with no changes post anti-PD1 therapy. In contrast, tumor cells were negative for PDL1.

CONCLUSION

This case represents a basis for optimism in potential use of anti-PD1 therapy in liver transplant candidates and supports further investigation of immune checkpoint inhibitors use in this unique patient population.

Investigation of discrepant mismatch repair immunohistochemistry and microsatellite instability polymerase chain reaction test results for gynecologic cancers using next-generation sequencing

Gynecologic cancers are routinely screened for DNA mismatch repair (MMR) gene mutations using immunohistochemistry (IHC) and/or polymerase chain reaction (PCR) for microsatellite instability (MSI) to enable selection of immune checkpoint inhibitor therapy and screen for Lynch syndrome. The limited data that compare IHC and MSI in endometrial tumors have shown discordance rates of 5-10%. We reviewed MMR/MSI results in gynecologic cancers and used next-generation sequencing (NGS) to interrogate discrepancies. Of the 328 cases with both IHC and MSI results, 256 (78.0%) were microsatellite stable (MSS) with preserved MMR (pMMR), 64 (19.5%) cases were MSI-High (MSI-H) with MMR deficient (dMMR), 2 cases showed subclonal loss of MLH1 and PMS2 with MSI-H, and 6 cases were discordant. Overall, there was a 98.2% (322/328) IHC/MSI concordance. Discordant cases were retested and/or subject to NGS. Of the six discrepant cases, five showed dMMR with MSS and one showed pMMR with MSI-H. One dMMR/MSI-L case showed loss of PMS2 with a germline pathogenic mutation. The pMMR/MSI-H case was found to harbor pathogenic variants in MLH1 and MSH6. One of the two cases with subclonal populations demonstrated MSI-H in the dMMR area and MSS in the pMMR area. These results emphasize the importance of selecting the appropriate tumor tissue for both IHC and molecular testing and demonstrate that NGS can help resolve discrepant MMR and MSI results.

Colonic Ganglioneuroma: A Rare Lesion With Extremely Different Presentations and Outcomes in Two Patients

Ganglioneuroma (GN) of the gastrointestinal tract is an extremely rare neuroectodermal tumor. Patients with ganglioneuromas have different presentations depending on the location, extent and size of the lesion. We present two cases of ganglioneuromas that had different clinical presentations and outcomes.

Harmonic Motion Imaging of Pancreatic Tumor Stiffness Indicates Disease State and Treatment Response

PURPOSE

Pancreatic ductal adenocarcinoma (PDA) is a common, deadly cancer that is challenging both to diagnose and to manage. Its hallmark is an expansive, desmoplastic stroma characterized by high mechanical stiffness. In this study, we sought to leverage this feature of PDA for two purposes: differential diagnosis and monitoring of response to treatment.

EXPERIMENTAL DESIGN

Harmonic motion imaging (HMI) is a functional ultrasound technique that yields a quantitative relative measurement of stiffness suitable for comparisons between individuals and over time. We used HMI to quantify pancreatic stiffness in mouse models of pancreatitis and PDA as well as in a series of freshly resected human pancreatic cancer specimens.

RESULTS

In mice, we learned that stiffness increased during progression from preneoplasia to adenocarcinoma and also effectively distinguished PDA from several forms of pancreatitis. In human specimens, the distinction of tumors versus adjacent pancreatitis or normal pancreas tissue was even more stark. Moreover, in both mice and humans, stiffness increased in proportion to tumor size, indicating that tuning of mechanical stiffness is an ongoing process during tumor progression. Finally, using a brca2-mutant mouse model of PDA that is sensitive to cisplatin, we found that tissue stiffness decreases when tumors respond successfully to chemotherapy. Consistent with this observation, we found that tumor tissues from patients who had undergone neoadjuvant therapy were less stiff than those of untreated patients.

CONCLUSIONS

These findings support further development of HMI for clinical applications in disease staging and treatment response assessment in PDA.

Cholinergic Signaling via Muscarinic Receptors Directly and Indirectly Suppresses Pancreatic Tumorigenesis and Cancer Stemness

In many solid tumors, parasympathetic input is provided by the vagus nerve, which has been shown to modulate tumor growth. However, whether cholinergic signaling directly regulates progression of pancreatic ductal adenocarcinoma (PDAC) has not been defined. Here, we found that subdiaphragmatic vagotomy in LSL-Kras +/G12D;Pdx1-Cre (KC) mice accelerated PDAC development, whereas treatment with the systemic muscarinic agonist bethanechol restored the normal KC phenotype, thereby suppressing the accelerated tumorigenesis caused by vagotomy. In LSL-Kras +/G12D;LSL-Trp53 +/R172H;Pdx1-Cre mice with established PDAC, bethanechol significantly extended survival. These effects were mediated in part through CHRM1, which inhibited downstream MAPK/EGFR and PI3K/AKT pathways in PDAC cells. Enhanced cholinergic signaling led to a suppression of the cancer stem cell (CSC) compartment, CD11b+ myeloid cells, TNFα levels, and metastatic growth in the liver. Therefore, these data suggest that cholinergic signaling directly and indirectly suppresses growth of PDAC cells, and therapies that stimulate muscarinic receptors may be useful in the treatment of PDAC.Significance: Subdiaphragmatic vagotomy or Chrm1 knockout accelerates pancreatic tumorigenesis, in part via expansion of the CSC compartment. Systemic administration of a muscarinic agonist suppresses tumorigenesis through MAPK and PI3K/AKT signaling, in early stages of tumor growth and in more advanced, metastatic disease. Therefore, CHRM1 may represent a potentially attractive therapeutic target. Cancer Discov; 8(11); 1458-73. ©2018 AACR. This article is highlighted in the In This Issue feature, p. 1333.

A precision oncology approach to the pharmacological targeting of mechanistic dependencies in neuroendocrine tumors

We introduce and validate a new precision oncology framework for the systematic prioritization of drugs targeting mechanistic tumor dependencies in individual patients. Compounds are prioritized on the basis of their ability to invert the concerted activity of master regulator proteins that mechanistically regulate tumor cell state, as assessed from systematic drug perturbation assays. We validated the approach on a cohort of 212 gastroenteropancreatic neuroendocrine tumors (GEP-NETs), a rare malignancy originating in the pancreas and gastrointestinal tract. The analysis identified several master regulator proteins, including key regulators of neuroendocrine lineage progenitor state and immunoevasion, whose role as critical tumor dependencies was experimentally confirmed. Transcriptome analysis of GEP-NET-derived cells, perturbed with a library of 107 compounds, identified the HDAC class I inhibitor entinostat as a potent inhibitor of master regulator activity for 42% of metastatic GEP-NET patients, abrogating tumor growth in vivo. This approach may thus complement current efforts in precision oncology.

Lysosomal acid lipase deficiency allograft recurrence and liver failure- clinical outcomes of 18 liver transplantation patients

Lysosomal acid lipase deficiency (LAL-D) results in progressive microvesicular hepatosteatosis, fibrosis, cirrhosis, dyslipidemia, and vascular disease. Interventions available prior to enzyme replacement therapy development, including lipid lowering medications, splenectomy, hematopoietic stem cell and liver transplantation were unsuccessful at preventing multi-systemic disease progression, and were associated with significant morbidity and mortality. We report two sisters, diagnosed in infancy, who succumbed to LAL-D with accelerated disease progression following splenectomy and liver transplantation. The index patient died one year after hematopoietic stem cell transplant and liver transplantation. Her younger sister survived five years post liver-transplantation, complicated by intermittent, acute rejection. Typical LAL-D hepatopathology, including progressive, microvesicular steatosis, foamy macrophage aggregates, vacuolated Kupffer cells, advanced fibrosis and micronodular cirrhosis recurred in the liver allograft. She died before a second liver transplant could occur for decompensated liver failure. Neither patient received sebelipase alfa enzyme replacement therapy, human, recombinant, lysosomal acid lipase enzyme, FDA approved in 2015. Here are reviewed 18 LAL-D post-liver transplantation cases described in the literature. Multi-systemic LAL-D progression occurred in 11 patients (61%) and death in six (33%). These reports demonstrate that liver transplantation may be necessary for LAL-D-associated liver failure, but is not sufficient to prevent disease progression, or liver disease recurrence, since the pathophysiology is predominantly mediated by deficient enzyme activity in bone marrow-derived monocyte-macrophages. Enzyme replacement therapy addresses systemic disease and hepatopathology, potentially improving liver-transplantation outcomes. This is the first systematic review of liver transplantation for LAL-D, and the first account of liver allograft LAL-D-associated hepatopathology recurrence.

Rare pancreatic tumors

In this review, we will focus on rare pancreatic tumors. Most of these tumors do not have distinct characteristic appearances so the key to diagnosis requires a combination of imaging appearance, laboratory data, patient demographics, and associated medical syndromes in order to narrow the differential diagnosis. Nonetheless, imaging plays a vital role in narrowing the differential and guiding management. While there are many variant pathologic entities that cannot be encompassed by a single review, we aim to illustrate the imaging appearance of less common pancreatic tumors highlighting key distinctive diagnostic characteristics and discuss the implications for management. While there is overlap in the imaging appearances of many of these entities, for educational purposes, lesions will be categorized into solid (hypoenhancing and hyperenhancing), cystic lesions, mesenchymal neoplasms, and neoplasms seen in younger patients (< 40 years).

β2 Adrenergic-Neurotrophin Feedforward Loop Promotes Pancreatic Cancer

Catecholamines stimulate epithelial proliferation, but the role of sympathetic nerve signaling in pancreatic ductal adenocarcinoma (PDAC) is poorly understood. Catecholamines promoted ADRB2-dependent PDAC development, nerve growth factor (NGF) secretion, and pancreatic nerve density. Pancreatic Ngf overexpression accelerated tumor development in LSL-Kras+/G12D;Pdx1-Cre (KC) mice. ADRB2 blockade together with gemcitabine reduced NGF expression and nerve density, and increased survival of LSL-Kras+/G12D;LSL-Trp53+/R172H;Pdx1-Cre (KPC) mice. Therapy with a Trk inhibitor together with gemcitabine also increased survival of KPC mice. Analysis of PDAC patient cohorts revealed a correlation between brain-derived neurotrophic factor (BDNF) expression, nerve density, and increased survival of patients on nonselective β-blockers. These findings suggest that catecholamines drive a feedforward loop, whereby upregulation of neurotrophins increases sympathetic innervation and local norepinephrine accumulation.

Abstract 5532: Functional role of Friend Leukemia Integration-1 (FLI1) in gastric carcinogenesis

Gastric adenocarcinoma (GC) is the 5th most common cancer worldwide but is the 3rd leading cause of cancer death. FLI1 (Friend leukemia integration-1) is an ETS family transcription factor that regulates genes involved in proliferation and differentiation. FLI1 is implicated in tumorigenesis, such as in Ewing’s sarcoma where a translocation creates an EWS-FLI1 oncogenic fusion protein. However, few studies have examined the role of FLI1 in carcinomas. In human breast cancer, overexpression of FLI1 led to inhibition of apoptosis, thereby promoting survival and malignant potential. In functional studies in a murine breast cancer model, however, downregulation of FLI1 increased malignant potential. In human GCs, we recently reported that FLI1 expression is inversely correlated with its promoter CpG methylation of the FLI1.

To determine if decreased expression occurs in GC epithelial cells or background non-epithelial cells, we analyzed 91 human GC tumors by immunohistochemistry (IHC) for FLI1 and compared them to normal gastric mucosa and intestinal metaplasia (IM) using an IHC composite scoring system accounting for intensity and percentage of epithelial cells expressing FLI1. We found that FLI1 is strongly expressed in normal gastric glandular epithelium and in IM, and that decreased expression was seen in most human GCs (P &lt; 1x10-17 vs normal, P &lt; 1x10-26 vs IM). These findings suggest that FLI1 acts as a tumor suppressor gene in GC. To test this hypothesis, we used an invasion assay and the human GC cell lines NUGC3 and SNU638, which have little to no FLI1 expression, respectively. Cultured GC cells were transduced to overexpress FLI1 or control, along with an eGFP reporter from an IRES (Lv203, Genecopoeia). After selection by puromycin, these GC cells were plated in serum-free media in the upper chamber on a Matrigel coated 8µm pore opaque membrane. Complete media with 10% fetal calf serum was plated in the lower chamber. Images were obtained of the lower membrane with an inverted fluorescent microscope and cellSens imaging software. Overexpression of FLI1 significantly decreased invasion by NUGC3 cells at 24 hours (P = 0.013) but not at 48 hours (P = 0.268) as compared to control. Overexpression of FLI1 significantly decreased invasion by SNU638 cells at both 24 and 48 hours (P = 0.027 and 0.012, respectively) as compared to control. Since NUGC3 cells have low FLI1 expression, we knocked down FLI1 by using a FLI1 shRNA lentiviral system with mCherry from an IRES as a reporter (LvRU6MP, Genecopoeia). Using the same invasion assay, knockdown of FLI1 trended towards a significant increase in invasion as compared to control at 48 hrs (P = 0.14), but not at 24 hrs (P = 0.73).

In summary, the combined observations in human GC tissue samples and the functional analyses in GC cells support a tumor suppressor role for FLI1 in human GC and also suggest that FLI1 and/or its target genes may be involved in regulatory mechanisms driving invasive properties of GC.

Citation Format: Armando Del Portillo, Elena V. Komissarova, Anne Koehne de Gonzalez, Aqiba Bokhari, Helen Remotti, Jorge Sepulveda, Antonia Sepulveda. Functional role of Friend Leukemia Integration-1 (FLI1) in gastric carcinogenesis [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 5532. doi:10.1158/1538-7445.AM2017-5532

Dclk1 Defines Quiescent Pancreatic Progenitors that Promote Injury-Induced Regeneration and Tumorigenesis

The existence of adult pancreatic progenitor cells has been debated. While some favor the concept of facultative progenitors involved in homeostasis and repair, neither a location nor markers for such cells have been defined. Using genetic lineage tracing, we show that Doublecortin-like kinase-1 (Dclk1) labels a rare population of long-lived, quiescent pancreatic cells. In vitro, Dclk1+ cells proliferate readily and sustain pancreatic organoid growth. In vivo, Dclk1+ cells are necessary for pancreatic regeneration following injury and chronic inflammation. Accordingly, their loss has detrimental effects after cerulein-induced pancreatitis. Expression of mutant Kras in Dclk1+ cells does not affect their quiescence or longevity. However, experimental pancreatitis converts Kras mutant Dclk1+ cells into potent cancer-initiating cells. As a potential effector of Kras, Dclk1 contributes functionally to the pathogenesis of pancreatic cancer. Taken together, these observations indicate that Dclk1 marks quiescent pancreatic progenitors that are candidates for the origin of pancreatic cancer.

Implementation of next generation sequencing into pediatric hematology-oncology practice: moving beyond actionable alterations

BACKGROUND

Molecular characterization has the potential to advance the management of pediatric cancer and high-risk hematologic disease. The clinical integration of genome sequencing into standard clinical practice has been limited and the potential utility of genome sequencing to identify clinically impactful information beyond targetable alterations has been underestimated.

METHODS

The Precision in Pediatric Sequencing (PIPseq) Program at Columbia University Medical Center instituted prospective clinical next generation sequencing (NGS) for pediatric cancer and hematologic disorders at risk for treatment failure. We performed cancer whole exome sequencing (WES) of patient-matched tumor-normal samples and RNA sequencing (RNA-seq) of tumor to identify sequence variants, fusion transcripts, relative gene expression, and copy number variation (CNV). A directed cancer gene panel assay was used when sample adequacy was a concern. Constitutional WES of patients and parents was performed when a constitutionally encoded disease was suspected. Results were initially reviewed by a molecular pathologist and subsequently by a multi-disciplinary molecular tumor board. Clinical reports were issued to the ordering physician and posted to the patient's electronic medical record.

RESULTS

NGS was performed on tumor and/or normal tissue from 101 high-risk pediatric patients. Potentially actionable alterations were identified in 38% of patients, of which only 16% subsequently received matched therapy. In an additional 38% of patients, the genomic data provided clinically relevant information of diagnostic, prognostic, or pharmacogenomic significance. RNA-seq was clinically impactful in 37/65 patients (57%) providing diagnostic and/or prognostic information for 17 patients (26%) and identified therapeutic targets in 15 patients (23%). Known or likely pathogenic germline alterations were discovered in 18/90 patients (20%) with 14% having germline alternations in cancer predisposition genes. American College of Medical Genetics (ACMG) secondary findings were identified in six patients.

CONCLUSIONS

Our results demonstrate the feasibility of incorporating clinical NGS into pediatric hematology-oncology practice. Beyond the identification of actionable alterations, the ability to avoid ineffective/inappropriate therapies, make a definitive diagnosis, and identify pharmacogenomic modifiers is clinically impactful. Taking a more inclusive view of potential clinical utility, 66% of cases tested through our program had clinically impactful findings and samples interrogated with both WES and RNA-seq resulted in data that impacted clinical decisions in 75% of cases.

Evaluating normalization approaches for the better identification of aberrant microRNAs associated with hepatocellular carcinoma

AIM

Dysregulated microRNAs (miRNAs) have been identified in hepatocellular carcinoma (HCC), but only a small proportion have been confirmed. An appropriate normalizer is crucial to determining the accuracy and reliability of data from miRNA studies.

METHODS

Different normalization strategies were used to validate genome-wide miRNA profiles in HCC tumor and non-tumor tissues, and to determine the consistency and discrepancy of data on dysregulated miRNAs.

RESULTS

Two sets of stable miRNAs (miR-30c/miR-30b and miR-30c/miR-126) were identified in HCC tissues by geNorm and NormFinder tools, respectively. The mean of global miRNAs also showed good stability for ranking the top 1-2 miRNAs, but the stabilities of the manufacturer-recommended ncRNAs controls were poor. Four panels of miRNAs were significantly associated with HCC by separately using various normalizers, and 14 miRNAs were consistently identified by three normalization strategies. Although fewer miRNAs (17-26) were dysregulated in HCC using the global mean or the 2 stable miRNAs as normalizers, perfect clustering of tissues was also obtained with only 1 to 2 misclassifications, suggesting the efficiency of the miRNA panels. Using global mean as the normalizer, the authors identified 7 miRNAs, including 2 novel (miR-324-5p and miR-550) significantly upregulated in HCC that were omitted when using 3 endogenous controls as the normalizer.

CONCLUSION

An optimal normalization strategy to identify biologically important miRNAs in HCC tissue studies of miRNA may be the combination of global mean and 2 stable miRNAs. Selection of appropriate normalization strategies to adjust miRNAs levels is particularly important for epidemiological studies dealing with large data sets and covering multiple experimental batches.

Identifying microRNA panels specifically associated with hepatocellular carcinoma and its different etiologies

AIM

Deregulation of microRNAs (miRNAs) expression has been identified in hepatocellular carcinoma (HCC), but few results are consistent. The objective of this study is to investigate "HCC tumor type specific" and "tumor common" miRNA panels.

METHODS

The authors integrate and analyze clinical, etiologic and miRNA profiles data from 9 types of solid tumors in The Cancer Genome Atlas (TCGA) and HCC data from Columbia University Medical Center (CUMC).

RESULTS

Levels of 33 miRNAs were significant different between HCC tumor and paired non-tumor tissues (over 2-fold changes) after Bonferroni correction for multiple comparisons, and most (28 miRNAs) were down-regulated in HCC tumors. Using this panel, the authors well classified HCC tumor tissues with 4 misclassifications among 48 paired tissues. Validating this panel in an additional 302 HCC tumor tissues, the authors almost perfectly distinguished tumor from non-tumor tissues with only two misclassifications (99% of HCC tissues correctly classified). Evaluating miRNA profiles in 32 independent HCC paired tissues from CUMC, the authors observed 40 miRNAs significantly deregulated in HCC with over 2-fold changes; 14 overlapped with those identified in TCGA. Subgroup analyses by HCC etiology found that 4 upregulated and 8 downregulated miRNAs were significantly associated with alcohol-related HCC. There were 7 and 4 miRNAs significantly associated with hepatitis B virus- and hepatitis C virus-related HCC, respectively. Data for the first time revealed that miR-24-1, miR-130a and miR-505 were significantly down-regulated only in HCC tumors; miR-142 and miR-455 were significantly down-regulated in HCC, but up-regulated in 5 other solid tumors; suggesting their HCC "tumor type specific" characteristics. A panel of 8 miRNAs was significant in at least 5 tumor types, including HCC, and was identified as "tumor common" marker.

CONCLUSION

The authors concluded that aberrant miRNA panels have HCC "tumor type specificity" and may be affected by etiologic factors.

Hepatocellular adenoma classification: a comparative evaluation of immunohistochemistry and targeted mutational analysis

BACKGROUND

Four subtypes of hepatocellular adenomas (HCA) are recognized: hepatocyte-nuclear-factor-1α mutated (H-HCA), β-catenin-mutated type with upregulation of glutamine synthetase (b-HCA), inflammatory type (IHCA) with serum-amyloid-A overexpression, and unclassified type. Subtyping may be useful since b-HCA appear to have higher risk of malignant transformation. We sought to apply subtype analysis and assess histological atypia, correlating these with next-generation sequencing analysis.

METHODS

Twenty-six HCA were stained with serum amyloid A (SAA), liver fatty acid-binding protein (LFABP), glutamine synthetase (GS), and β-catenin IHC, followed by analysis with a targeted multiplex sequencing panel.

RESULTS

By IHC, 4 HCA (15.4 %) were classified as b-HCA, 11 (42.3 %) as IHCA, 9 (34.6 %) as H-HCA, and two (7.7 %) unclassifiable. Eight HCA (30.8 %) showed atypia (3 b-HCA, 4 IHCA and 1 H-HCA). Targeted sequencing confirmed HNF1A mutations in all H-HCA, confirming reliability of LFABP IHC in identifying these lesions. CTNNB1 mutations were detected in 1 of 4 (25 %) of GS/β-catenin-positive cases, suggesting that positive GS stain does not always correlate with CTNNB1 mutations.

CONCLUSIONS

Immunohistochemistry does not consistently identify b-HCA. Mutational analysis improves the diagnostic accuracy of β-catenin-mutated HCA and is an important tool to assess risk of malignancy in HCA.

HepPar-1 and Arginase-1 Immunohistochemistry in Adenocarcinoma of the Small Intestine and Ampullary Region

CONTEXT :HepPar-1 and Arginase-1 are urea cycle enzymes used to distinguish hepatocellular carcinoma from other carcinomas. HepPar-1, but not Arginase-1, is known to be immunoreactive with normal human small intestine.

OBJECTIVES

To better define and compare the immunohistochemical staining patterns of HepPar-1 and Arginase-1 in adenocarcinomas arising in the small intestine, including the ampullary region.

DESIGN

Staining for HepPar-1 and Arginase-1 was performed on 20 nonampullary small intestinal adenocarcinomas and 32 adenocarcinomas from the ampullary region. Ampullary adenocarcinomas were divided into intestinal morphology (15), pancreatobiliary morphology (14), and unclassifiable (3). Nonneoplastic small intestinal mucosa and colorectal adenocarcinomas were used as control groups.

RESULTS

HepPar-1 stained 12 of 20 nonampullary small intestinal adenocarcinomas, with a median of 63% of cells staining in positive cases. It also stained 11 of 15 ampullary carcinomas with intestinal morphology, with a median of 75% of cells staining in positive cases. Two of 14 ampullary carcinomas with pancreatobiliary morphology were positive for HepPar-1. Arginase-1 showed positivity in 2 ampullary region carcinomas and diffuse positivity in 1 duodenal adenocarcinoma. Two of 22 colorectal carcinomas stained for HepPar-1 with none positive for Arginase-1.

CONCLUSIONS

HepPar-1, but not Arginase-1, usually shows positivity in small intestinal adenocarcinomas and ampullary adenocarcinomas with intestinal morphology, but only rarely shows positivity in ampullary adenocarcinomas with pancreatobiliary morphology. HepPar-1 positivity in metastatic adenocarcinoma with intestinal morphology is suggestive of an upper gastrointestinal primary site.

Abstract 4770: Levels of 5-methyl-cytosine and 5-hydroxymethyl-cytosine in hepatocellular carcinoma prognosis

Hepatocellular carcinoma (HCC) is the third most common cause of cancer death in the world. The US incidence of HCC has tripled between 1975 and 2005 and has been accompanied by improved long term survival rates, but as a result of HCC ‘s poor prognosis, 1-year survival remains lower than fifty percent. Therefore, a better understanding of the molecular mechanisms underlying the disease process is currently needed. Epigenetic alterations have been linked to HCC and global genomic hypomethylation is a well known hallmark of the disease. Less is understood about the role hydroxymethylation plays in HCC carcinogenesis. Here, we conducted a study to determine 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) levels by UPLC/MS/MS in HCC tumor (T) and non-tumor (NT) adjacent tissue DNAs of sixty six individuals treated at Columbia Presbyterian Medical Center in New York. We analyzed the association between demographic and clinicopathological characteristics and 5mC and 5hmC levels, as well as performed a Cox-survival analysis to determine which factors better predicted survival. Mean levels of 5mC (5mCT = 3.15±0.49% vs.5mCNT = 3.80±0.12% (p&lt;0.0001) and 5hmC (5hmCT = 0.11±0.04% vs. 5hmCNT = 0.23±0.07%, p&lt;0.0001) in tumor tissues were statistically significantly lower than in non-tumor tissues. Older age was associated with lower 5mC content (5mC&lt;60y = 3.32±0.43% vs. 5mC≥60y = 3.00±0.50%, p = 0.001), while tumor DNA of transplant (LT) patients had higher 5hmC levels compared to surgical resection (LR) patients (5hmCLR = 0.10±0.04% vs. 5hmCLT = 30.13±0.04%, p = 0.0053). However, survival was predicted by whether transplant or resection were performed (Hazard ratio LT vs. LR, 3.54 (95% confidence interval:1.34-9.29), p = 0.01). Our study had a limited sample size, but suggests that future studies of 5hmC might be informative concerning HCC prognosis.

Citation Format: Lissette Delgado-Cruzata, Hui Chen Wu, Tiffany Thomas, Abby B. Siegel, Jing Shen, Yu-Jing Zhang, Abhishek Goyal, Christine C. Hsu, Helen Remotti, Regina M. Santella. Levels of 5-methyl-cytosine and 5-hydroxymethyl-cytosine in hepatocellular carcinoma prognosis. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4770. doi:10.1158/1538-7445.AM2015-4770

Abstract B73: Adrenergic signaling promotes pancreatic tumor initiation and progression

Background/Aims: There is increasing evidence that chronic sympathetic nervous system activation can lead to increased noradrenaline levels in the tumor microenvironment. This process has been associated with proliferative signals largely mediated by beta-adrenergic signaling. However, the mechanisms by which adrenergic neurotransmitters are delivered to the tumor microenvironment are not well understood. In this study we aimed to investigate the role of locally and systemically delivered catecholamines to the tumor microenvironment in a well-established genetically engineered pancreatic cancer mouse model (PDx1-Cre/KRasG12D (KC) and PDx1-Cre/KRasG12D/Trp53R172H (KPC)).

Methods: Adrenergic signaling was induced or inhibited in KC or KPC mice or 3D pancreatic spheres in culture using specific non-selective and selective agonists or antagonists. Adrenergic receptor expression was assessed by RT-PCR, Western blot and immunohistochemistry. Adrenergic signaling was also modeled in vivo applying restraint stress. To elucidate the crosstalk between nerve and cancer cells, pancreatic spheres and pancreatic cancer cells were co-cultured with dorsal root ganglia and neuronal plasticity was quantified by evaluating neurite outgrowth and number of branches. Denervation of the pancreas was performed using surgical or chemical neural ablation.

Results: Adrenergic signaling receptors, in particular ADRB2, is upregulated during pancreatic cancer development. Furthermore, in vitro stimulation of cells harboring an oncogenic KRas mutation displayed a significantly increased sphere forming efficiency. This effect was blocked by the non-specific beta-blocker propranolol and the selective beta2-blocker ICI 188,551. Stimulation of pancreatic sphere formation from KC mice induced by adrenergic signaling from dorsal root ganglia in vitro was also prevented by selective blockage of the beta2-adrenergic signaling pathway. While surgical or chemical (Botulinum toxin A) denervation of the pancreas appeared not to retard the development precancerous lesions in KC mice, denervation significantly increased the survival when performed in mice after a tumor (3-5mm) was detected by high–resolution ultrasound imaging. In contrast, stress accelerated pancreatic cancer development in KC mice. The effects of stress were prevented by treatment with the selective ADRB2 antagonist ICI 188,551.

Conclusions: Taken together, our data suggests that an increased level of stress and an increased level of systemic catecholamines may promote pancreatic carcinogenesis in its early stages. During this phase, patients might benefit from pharmacological inhibition of stress-induced signaling. The progression of pancreatic cancer seems to depend on the local delivery of catecholamines to the microenvironment, and thus patients might also benefit by additional targeting of the ADRB2 signaling pathway.

Citation Format: Bernhard W. Renz, Christoph B. Westphalen, Xiaowei Chen, Yoku Hayakawa, Yoshihiro Takemoto, Marina Macchini, Daniel L. Worthley, Samuel Asfaha, Axel Kleespies, Helen Remotti, Kenneth P. Olive, Timothy C. Wang. Adrenergic signaling promotes pancreatic tumor initiation and progression. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Innovations in Research and Treatment; May 18-21, 2014; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2015;75(13 Suppl):Abstract nr B73.

Neoadjuvant gemcitabine, docetaxel, and capecitabine followed by gemcitabine and capecitabine/radiation therapy and surgery in locally advanced, unresectable pancreatic adenocarcinoma

BACKGROUND

This prospective study was undertaken to assess toxicity, resectability, and survival in pancreatic adenocarcinoma patients presenting with locally advanced, unresectable disease treated with neoadjuvant gemcitabine, docetaxel, and capecitabine (GTX) and gemcitabine and capecitabine (GX)/radiation therapy (RT).

METHODS

All patients presenting to the Pancreas Center were evaluated for eligibility. Forty-five patients (mean age, 64 years; range, 44-83 years)-34 patients deemed unresectable because of arterial involvement and 11 patients deemed unresectable because of extensive venous involvement-were treated with 6 cycles of GTX. Those with arterial involvement were treated with GX/RT after chemotherapy.

RESULTS

The GTX and GX/RT treatments were tolerated with the expected drug-related toxicities. There were no bowel perforations, cases of pancreatitis, or delayed strictures. Among those with arterial involvement, 29 underwent subsequent resection, with 20 (69%) achieving R0 resections. All 11 patients with venous-only involvement underwent resection, with 8 achieving R0 resections and 3 achieving complete pathologic responses. For the arterial arm, the 1-year survival rate was 71% (24 of 34 patients), and the median survival was 29 months (95% confidence interval, 21-38 months). Thirteen patients (38%) have not relapsed (range, 5-49+ months). For the venous arm, the median survival has not been reached at more than 42 months. Six patients (55%) in the venous arm did not experience recurrence (range, 6.2-42+ months).

CONCLUSIONS

GTX plus GX/RT is an effective neoadjuvant regimen that can be safely administered to patients up to at least the age of 83 years. It is associated with a high response rate, a high rate of R0 resections, and prolonged overall survival.

Phase I trial of sorafenib following liver transplantation in patients with high-risk hepatocellular carcinoma

Liver transplantation offers excellent long-term survival for hepatocellular carcinoma (HCC) patients who fall within established criteria. For those outside such criteria, or with high-risk pathologic features in the explant, HCC recurrence rates are higher. We conducted a multicenter phase I trial of sorafenib in liver transplantation patients with high-risk HCC. Subjects had HCC outside the Milan criteria (pre- or post-transplant), poorly differentiated tumors, or vascular invasion. We used a standard 3+3 phase I design with a planned duration of treatment of 24 weeks. Correlative studies included the number of circulating endothelial cells (CECs), plasma biomarkers, and tumor expression of p-Erk, p-Akt, and c-Met in tissue micro-arrays. We enrolled 14 patients with a median age of 63 years. Of these, 93% were men and 71% had underlying hepatitis C virus (HCV) and 21% had HBV. The maximum tolerated dose of sorafenib was 200 mg BID. Grade 3-4 toxicities seen in >10% of subjects included leukopenia (21%), elevated gamma-glutamyl transferase (21%), hypertension (14%), hand-foot syndrome (14%) and diarrhea (14%). Over a median follow-up of 953 days, one patient died and four recurred. The mean CEC number at baseline was 21 cells/4 ml for those who recurred, and 80 cells/4 ml for those who did not (p=0.10). Mean soluble vascular endothelial growth factor receptor-2 levels decreased after 1 month on sorafenib (p=0.09), but did not correlate with recurrence. There was a trend for tumor c-Met expression to correlate with increased risk of recurrence. Post-transplant sorafenib was found to be feasible and tolerable at 200 mg PO BID. The effect of post-transplant sorafenib on recurrence-free survival is potentially promising but needs further validation in a larger study.

Strategies for improving diagnostic accuracy of biliary strictures

BACKGROUND

Brush cytology is the initial intervention when evaluating biliary strictures. Biliary brush cytology is known for its low sensitivity (but high specificity) and may be accompanied by biopsies and/or fluorescent in situ hybridization (FISH) to improve diagnostic yield. This study aimed to identify features to enhance cytological sensitivity, and assess which sampling method(s) improve identification of pancreatobiliary adenocarcinomas (PBCa).

METHODS

Seventy-three biliary stricture cases were retrieved (38 PBCa and 35 control benign strictures). Biliary brushings, FISH, and biopsies were reviewed. Cytology specimens were evaluated for cellularity and presence of drunken honeycomb (DH), loosely cohesive clusters of round cells (LCCRC), large atypical cells with foamy cytoplasm (LACF), and single vacuolated malignant cells (SCs). Biopsies were examined for the presence of stromal invasion (SI).

RESULTS

Biliary brushings were scantly cellular in 47.4% of PBCa and 51.4% of controls, resulting in 69.6% nondiagnostic/false-negative cytology diagnoses. DH, LACF, and SCs were significantly associated with adenocarcinoma (P < .00001, .0033, and .00002, respectively). By univariate analysis, SCs and LACF were predictors of malignancy in brushings (P = .0002 and .05). By multivariate analysis, only SCs were predictive of malignancy (P = .002). SI facilitated the diagnosis in 9 biopsies. Sensitivity/specificity of brush cytology, FISH, and biopsy were 39.5%/94.3%, 63.9%/94.3%, and 84.2%/100%, respectively.

CONCLUSIONS

The low sensitivity of biliary brushings results from limited cellularity. Identification of LACF, DH, and SCs improves sensitivity. Sampling of stromal tissue may facilitate PBCa diagnosis. Concurrent biopsies and FISH are helpful in enhancing the diagnostic yield of PBCa.

High response rates and prolonged survival in patients with corticotroph pituitary tumors and refractory Cushing disease from capecitabine and temozolomide (CAPTEM): a case series

BACKGROUND AND IMPORTANCE

Rarely, corticotrophic pituitary tumors take on an aggressive form characterized by rapid growth, invasion into local structures, compression of cranial nerves, and possible spread to distant sites. When conventional surgery, radiation therapy, and hormones fail to control progression and symptoms, alternative therapies are needed. A novel chemotherapeutic regimen of capecitabine and temozolomide (CAPTEM), originally designed in our laboratory, demonstrated dramatic antineoplastic effects against corticotrophic pituitary tumors.

CLINICAL PRESENTATION

We present a case series of 4 patients with aggressive, adrenocorticotrophic hormone--producing pituitary tumors who had previously depleted all surgical, radiation, and hormonal therapies and were then treated with CAPTEM. Dramatic clinical improvements in neurological deficits and Cushing symptoms were evident in all patients after treatment was initiated. Confirmed by radiographic imaging, 2 of 4 patients demonstrated complete regression of disease, 1 patient had a 75% regression, and the fourth patient has ongoing stable disease for > 4.5 years at the time of this writing. Immunohistochemical analysis of patients' tumor samples showed low O-methyguanyl methyltransferase expression and adequate levels of mismatch repair enzymes (MLH-1, MSH-2, MSH-6, and PMS-2), which are important for the in vivo efficacy of CAPTEM.

CONCLUSION

This is the first report of prolonged antitumor response to and radiographic complete remissions as a result of CAPTEM in patients with aggressive pituitary tumors who had exhausted all other therapies.

Abstract 4092: Long-lived Dclk1+ cells serve as colon cancer initiating cells

Introduction: In the rapidly proliferating gastrointestinal epithelium, long-lived tissue stem cells, characterized by multipotentiality and self-renewing ability, remain the most likely cellular origin for cancer. Previous studies have suggested actively cycling Lgr5+ stem cells are one cellular origin for intestinal adenomas. However, it has also recently been suggested that non-Lgr5+ cells may also contribute to the cellular origin of colorectal cancer. Doublecortin-like kinase 1 (Dclk1) protein is a gastrointestinal tuft cell marker that has been proposed to identify quiescent stem cells and cancer stem cells that sustain tumor growth. The role of Dclk1+ tuft cells within the gastrointestinal epithelium and their potential to function as cancer-initiating cells, however, remain poorly understood. Here, we used Dclk1(BAC)-CreERT;ROSA26rLacZ mice crossed to APCff mice to examine whether Dclk1+ cells contribute to colonic tumor formation.

Methods: To recapitulate the endogenous expression pattern of Dclk1, we used a BAC strategy and generated a transgenic mouse with a Tamoxifen inducible Cre under the control of the Dclk1 promoter (Dclk1-BAC-Cre-ERT). Dclk1-CreERT mice were crossed to both ROSA26rLacZ and APCff mice and treated with tamoxifen (6 mg p.o.). Dclk1+ lineage tracing was assessed by X-gal staining. To examine the contribution of the Dclk1+ cells to colonic tumorigenesis, we treated Dclk1(BAC)-CreERT;ROSA26rLacZ; APCff mice with DSS (3% in drinking water) to induce colitis. Mice were sacrificed 3-4 months after DSS weeks to assess for tumor formation and X-gal staining performed to stain for the Dclk1+ cell lineage.

Results: Dclk1-BAC-CreERT genetic lineage tracing demonstrated that a subpopulation of Dclk1+ cells is extremely long-lived and shows rare stem cell abilities. Moreover, genetic ablation reveals a pivotal role for Dclk1+ tuft cells in the response to intestinal and colonic injury. Surprisingly, conditional loss of APC in Dclk1+ cells is not sufficient to drive colonic carcinogenesis, whereas induction of DSS colitis in Dclk1-CreERT; APCflox/flox mice leads to the development of poorly differentiated colonic adenocarcinoma. Importantly, colonic tumor formation occurs even when the onset of colitis is delayed for up to 3 months after APC loss in Dclk1+ cells.

Conclusions. Thus, our data define a novel intestinal Dclk1+ tuft cell population that is long-lived, quiescent and important for intestinal homeostasis and regeneration. Long-lived Dclk1+ cells maintain quiescence even following oncogenic mutation, but are activated by tissue injury and can serve as a potent cellular origin of colon cancer.

Citation Format: Samuel Asfaha, Christoph Benedikt Westphalen, Yoku Hayakawa, Yoshihiro Takemoto, Dana J. Lukin, Wanda Setlik, Helen Remotti, Ashlesha Muley, Xiaowei Chen, Randal May, Courtney W. Houchen, James G. Fox, Michael D. Gershon, Michael Quante, Timothy Wang. Long-lived Dclk1+ cells serve as colon cancer initiating cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4092. doi:10.1158/1538-7445.AM2014-4092

Abstract 285: Integrative analyses of genome-wide expression of miRNAs and DNA methylation patterns in hepatocellular carcinoma to improve functional biomarker identification

Previous studies, including ours have examined aberrant expression of microRNAs (miRNAs) and altered DNA methylation, and several miRNAs have been identified as regulated by DNA methylation. However, whether this mechanism occurs at a genome-wide level and is related to the profiles of dysregulated miRNA commonly observed in hepatocellular carcinoma (HCC) patients is largely unknown. Using a two-phase study design, we conducted a genome-wide screening for miRNA expression and DNA methylation profiles in the tumor and adjacent non-tumor tissues from US HCC cases. The discovery and validation sets included, respectively, 10 and 56 paired tumor/non-tumor tissues. TaqMan Low Density Arrays (TLDA) covering 733 miRNAs were used to measure expression profiles, and quantitative RT-PCR was used to validate candidate miRNA signatures. Infinium HumanMethylation 450K BeadChip arrays covering 3,439 CpG sites for 727 miRNAs were used to determine DNA methylation patterns. Comparing expression profiles in HCC tumor and adjacent non-tumor tissues, we found that 25 miRNAs were statistically significantly different with over 2-fold expression changes after adjusting for false discovery rate (FDR); a perfect classification of HCC tissues was observed. Six of the aberrant miRNAs were over-expressed in HCC tumor tissue (range from 2.7 to 18-fold), while 19 miRNAs were downregulated in tumor tissue (range from -2.5 to -7.5-fold). Several miRNAs (miR-139, miR-196b, miR-381, miR-486 and miR-1180) were identified for the first time as having a role in hepatocarcinogenesis. After Bonferroni adjustment, a total of 1,256 CpG sites covering 412 miRNAs showed significant differences in DNA methylation levels between tumor and adjacent non-tumor tissues, including 185 hypermethylated and 1,071 hypomethylated CpG sites in tumor tissues. We further conducted integrative analyses of the correlations between miRNAs expression and DNA methylation patterns for 222 miRNAs detected in over 80% of the tissue samples. As expected, inverse correlations were observed for 91.7% (55/60) of up-regulated miRNAs with a DNA hypomethylation change, and for 48.1% (78/162) of down-regulated miRNAs with a DNA hypermethylation change. However, for only 8 miRNAs’ (3.6%) did expression levels achieve statistically significant differences between tumor and non-tumor tissues in accord with DNA methylation alterations. A validation study of six of the candidates in an additional 56 paired HCC tissues confirmed the aberrant miRNAs expression patterns observed in tumor tissue. The inverse correlations between miRNAs’ expression and DNA methylation were concordant for all 27 CpG sites in the 4 miRNAs (miR-18a, miR-125b-1, miR-182 and miR-199a-1). These data suggest that a small proportion of DNA methylation changes can lead to significant dysregulation of miRNAs in HCC tumor tissue.

Citation Format: Jing Shen, Shuang Wang, Abby B. Siegel, Helen Remotti, Qiao Wang, Iryna Sirosh, Regina M. Santella. Integrative analyses of genome-wide expression of miRNAs and DNA methylation patterns in hepatocellular carcinoma to improve functional biomarker identification. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 285. doi:10.1158/1538-7445.AM2014-285

Long-lived intestinal tuft cells serve as colon cancer-initiating cells

Doublecortin-like kinase 1 protein (DCLK1) is a gastrointestinal tuft cell marker that has been proposed to identify quiescent and tumor growth-sustaining stem cells. DCLK1⁺ tuft cells are increased in inflammation-induced carcinogenesis; however, the role of these cells within the gastrointestinal epithelium and their potential as cancer-initiating cells are poorly understood. Here, using a BAC-CreERT-dependent genetic lineage-tracing strategy, we determined that a subpopulation of DCLK1⁺ cells is extremely long lived and possesses rare stem cell abilities. Moreover, genetic ablation of Dclk1 revealed that DCLK1⁺ tuft cells contribute to recovery following intestinal and colonic injury. Surprisingly, conditional knockdown of the Wnt regulator APC in DCLK1⁺ cells was not sufficient to drive colonic carcinogenesis under normal conditions; however, dextran sodium sulfate-induced (DSS-induced) colitis promoted the development of poorly differentiated colonic adenocarcinoma in mice lacking APC in DCLK1⁺ cells. Importantly, colonic tumor formation occurred even when colitis onset was delayed for up to 3 months after induced APC loss in DCLK1⁺ cells. Thus, our data define an intestinal DCLK1⁺ tuft cell population that is long lived, quiescent, and important for intestinal homeostasis and regeneration. Long-lived DCLK1⁺ cells maintain quiescence even following oncogenic mutation, but are activated by tissue injury and can serve to initiate colon cancer.

Exploration of genome-wide circulating microRNA in hepatocellular carcinoma: MiR-483-5p as a potential biomarker

BACKGROUND

MicroRNAs (miRNA) are abundant in the circulation and play a central role in diverse biologic processes; they may be useful for early diagnosis of hepatocellular carcinoma.

METHODS

We conducted a two-phase, case-control study (20 pairs for the discovery set and 49 pairs for the validation set) to test the hypothesis that genome-wide dysregulation of circulating miRNAs differentiates hepatocellular carcinoma cases from controls. Taqman low-density arrays were used to examine genome-wide miRNA expression for the discovery set, and quantitative real-time PCR was used to validate candidate miRNAs for both discovery and validation sets.

RESULTS

Sixty-six miRNAs were found to be significantly overexpressed in plasma of hepatocellular carcinoma cases compared with controls after adjusting for false discovery rate (P < 0.05). A volcano plot indicated that seven miRNAs had greater than 2-fold case-control differences with P < 0.01. Four significant miRNAs (miR-150, miR-30c, miR-483-5p, and miR-520b) detectable in all samples with varied expression levels were further validated in a validation set. MiR-483-5p was statistically significantly overexpressed in hepatocellular carcinoma cases compared with controls (3.20 vs. 0.82, P < 0.0001). Hepatocellular carcinoma risk factors and clinic-pathological characteristics did not influence miR-483-5p expression. The combination of plasma miR-483-5p level and hepatitis C virus status can significantly differentiate hepatocellular carcinoma cases from controls with an area under the curve of 0.908 (P < 0.0001). The sensitivity and specificity were, respectively, 75.5% and 89.8%.

CONCLUSIONS

These preliminary results suggest the importance of dysregulated circulating miR-483-5p as a potential hepatocellular carcinoma biomarker.

IMPACT

Confirmation of aberrant expression of miR-483-5p in a large prospective hepatocellular carcinoma study will provide support for its application to hepatocellular carcinoma detection.

Predictors of recurrence in intraductal papillary mucinous neoplasm: experience with 183 pancreatic resections

OBJECTIVES

We examined long-term outcomes in patients with surgically treated intraductal papillary mucinous neoplasm (IPMN) to determine if any clinical or histologic features could predict risk of recurrent disease.

METHODS

We reviewed 183 margin-negative surgical resections performed for IPMN between 1994 and 2011 with documented postoperative abdominal imaging. We calculated time to recurrent disease as indicated by radiographic change and created a multivariable Cox proportional hazards model to assess the relationship between patient characteristics and histopathologic tumor features and disease recurrence.

RESULTS

Among patients with margin-negative resections and adequate imaging follow-up, we observed a recurrence rate of 13% over a median follow-up of 32.0 months. Individuals with invasive tumors on original pathology were more likely to recur (HR 5.2, 95% CI 2.2-12.2); however, original pathology did not predict disease severity on recurrence. Controlling for invasive pathology, no other histologic feature of the original tumor, including dysplasia at the surgical margin, predicted recurrence. Among non-invasive IPMN, pancreatitis was associated with disease recurrence (HR 3.6, 95% CI 1.2-10.7).

CONCLUSIONS

The frequency of recurrent disease in this population and the inability to predict recurrence argues for universal and continuous surveillance after resection for IPMN. The relationship between pancreatitis and disease recurrence should be investigated further.

Fine-needle aspirations of pancreatic serous cystadenomas: improving diagnostic yield with cell blocks and α-inhibin immunohistochemistry

BACKGROUND

The diagnosis of serous cystadenoma (SCA), a rare benign pancreatic neoplasm, can alter the management of patients with pancreatic masses. Although characteristic imaging findings and fluid chemical analysis have been described, SCAs are not always recognized preoperatively. Furthermore, scant cellular yield on fine-needle aspiration (FNA) often leads to a nondiagnostic or nonspecific benign diagnosis. α-Inhibin (AI), a sensitive marker for SCA, is infrequently required for diagnosis in surgical specimens due to their characteristic histologic appearance. The objective of the current study was to determine whether AI staining can improve SCA diagnosis on FNA specimens.

METHODS

Fifteen confirmed cases of SCA with prior FNA specimens were selected for this study. FNAs were evaluated for cellularity, cellular arrangement, and cytomorphology. Resection specimens were reviewed.

RESULTS

Of the 15 FNA cases, approximately 75% demonstrated scant cellularity (11 of 15 cases). On smears, the cells were arranged as flat sheets, corresponding to strips of cells on cell block sections. The cells were small and round to cuboidal, with clear cytoplasm; occasional plasmacytoid cells and oncocytic cells were identified. Flattened cells, corresponding to attenuated epithelial cells lining macrocysts on the resections, were also noted. Stromal fragments were present in 5 FNAs and correlated with the hyalinized stroma in the resection specimens. AI immunostaining was positive in 88% of cases (7 of 8 of cases), thereby supporting the diagnosis of SCA.

CONCLUSIONS

The results of the current study indicate that low cellularity and bland cytology are inherent to SCAs. Performing cell blocks and AI staining on FNA specimens is useful for establishing the diagnosis of SCA. An immunohistochemical panel including AI, chromogranin, and synaptophysin may enhance the diagnostic accuracy of pancreatic FNA specimens.

Abstract 1215: Loss of PTEN expression predicts poor prognosis in patients with intraductal papillary mucinous neoplasms of the pancreas

Purpose: Previously we have reported PIK3CA gene mutations in high-grade intraductal papillary mucinous neoplasms (IPMNs). However, the contribution of phosphatidylinositol-3 kinase pathway (PI3K) deregulation to pancreatic carcinogenesis is not fully understood and its prognostic value unknown. Here we conducted a comprehensive examination of the PI3K signaling pathway to gain an understanding of the extent of its deregulation in IPMN and the potential impact on clinical outcomes. Experimental Design: Thirty-six IPMN specimens were evaluated for the E542K and E545K (exon 9), and H1047R (exon 20) hot-spot mutations in the PIK3CA gene and E17K mutation in the AKT1 gene using novel mutant-enriched sequencing methods. PIK3CA and AKT1 gene amplifications and PTEN loss of heterozygosity (LOH) were also investigated. In addition, the expression levels of 3-phosphoinositide dependent protein kinase-1 (PDPK1/PDK1), PTEN/MMAC phosphatase and Ki67 proliferation marker were analyzed by immunohistochemistry in the samples.

Results: Derangements at genetic level of at least one member of the PI3K pathway was detected in 18 of the 36 (50 %). Three of the 36 (8.3 %) IPMN cases carried the E17K mutation in the AKT1 gene and one case carried the H1047R mutation in the PIK3CA gene. PDK1 was significantly overexpressed in the IPMC (15/17; 88 %) vs IPMN (5/19; 26 %) (p = 0.000) and in intestinal and pancreatic-type of IPMN than gastric-type of IPMN (p = 0.015). PDK1 overexpression was also associated with higher proliferation index by Ki67 staining (p = 0.044). Loss of PTEN expression strongly correlated to reduced survival in this group of IPMN patients (p = 0.014).

Conclusion: This is the first study showing AKT1 activating mutation in this subtype of pancreatic cancer using a novel mutant-enriched method. Our data, when combined with previous reports, indicate that oncogenic activation of the PI3K pathway involving PIK3CA and AKT1 genes mutations or aberrant expression of its members, in particular loss of PTEN expression and overexpression of PDK1 is a frequent event and can contribute to the progression of IPMNs. This finding suggests the potential employment of target therapies aiming at the PI3K signaling pathway for IPMN patients. More importantly, the incorporation of PTEN expression status in making surgical decisions for IPMN patients may have significant clinical impacts and should warrant further investigations.

Citation Format: Dario Garcia-Carracedo, Andrew T. Turk, Stuart Fine, Nathan Akhavan, Benjamin C. Tweel, Ramon E. Parsons, John A. Chabot, John D. Allendorf, Helen Remotti, Gloria H. Su. Loss of PTEN expression predicts poor prognosis in patients with intraductal papillary mucinous neoplasms of the pancreas. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1215. doi:10.1158/1538-7445.AM2013-1215

Abstract LB-25: Exploration of genome-wide circulating microRNA in hepatocellular carcinoma (HCC) - dysregulation of miR-483-5p and miR-150 as diagnostic marker

The incidence of hepatocellular carcinoma (HCC) has doubled over the past 20 years in the United States (US). HCC prognosis is poor if not diagnosed and treated at an early stage. MicroRNAs (miRNAs) are a class of small non-coding RNAs that control gene expression by inhibiting translation or inducing cleavage of target messenger RNAs (mRNAs). miRNAs can regulate diverse biological processes including DNA repair, apoptosis, cell proliferation, differentiation and immune function. Circulating miRNAs in cell-free plasma/serum samples have been consistently observed to have high stability and resistance to storage/handling, suggesting their potential use as diagnostic biomarkers. We conducted a two-phase epidemiological case-control study to test the hypothesis that genome-wide dysregulation of circulating miRNAs differentiate HCC cases from controls. A total of 69 HCC patients and 69 controls were recruited and matched on age, gender and ethnicity. Taqman low density arrays were used to examine genome-wide miRNA expression, and quantitative RT-PCR was used to validate promising candidates. Sixty-six miRNAs were found to be significantly over-expressed in plasma of HCC cases compared to controls after adjusting for false discovery rate (p&lt;0.05). A volcano plot indicated that 7 miRNAs had over 2-fold case-control differences with p&lt;0.01. Four significant miRNAs (miR-150, miR-30c, miR-483-5p and miR-520b) detectable in all samples with varied expression levels were further validated in an expanded case-control study. MiR-483-5p was statistically significantly over-expressed in HCC cases compared with controls (3.25 vs. 0.54, p&lt;0.0001). MiR-150 was up-regulated in HCC, but the difference was not significant (5.66 vs. 5.29). The combination of plasma levels of miR-483-5p and miR-150 can significantly differentiate HCC cases from controls with an AUC of 0.850 (p&lt;0.0001). The sensitivity and specificity were, respectively, 63.8% and 85.5%. These preliminary data indicated the importance of dysregulated circulating miRNAs in hepatocarcinogenesis, and suggesting the possibility of using miR-483-5p and miR-150 as diagnostic biomarkers. Large prospective studies are necessary to replicate the current findings, and evaluate the panel of circulating miRNAs in improving early diagnosis of HCC.

Citation Format: Jing Shen, Antai Wang, Qiao Wang, Irina Gurvich, Abby B. Siegel, Helen Remotti, Regina M. Santella. Exploration of genome-wide circulating microRNA in hepatocellular carcinoma (HCC) - dysregulation of miR-483-5p and miR-150 as diagnostic marker. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-25. doi:10.1158/1538-7445.AM2013-LB-25

Tissue microarrays: construction and use

Tissue microarrays (TMAs) enable high-throughput tissue analysis by selecting a large number of -paraffin-embedded donor tissue block cores and transferring these tissue cores into a positionally encoded array in the recipient TMA block. Once TMAs are constructed, a variety of analysis may be performed on the arrays including histochemical, immunohistochemical, or immunofluorescent staining, and in situ hybridization for DNA or RNA. TMAs offer a cost-effective method for performing parallel analysis of a large number of tissue samples. In this chapter we outline the method of TMA construction with an emphasis on providing useful information in the analysis of a variety of pancreatic neoplasms, including pancreatic adenocarcinomas and pre-invasive lesions. The technique of TMA construction in this chapter is restricted to the use of formalin-fixed paraffin-embedded tissue.

Exploring genome-wide DNA methylation profiles altered in hepatocellular carcinoma using Infinium HumanMethylation 450 BeadChips

Hepatocellular carcinoma (HCC) incidence has increased in the US and also has one of the fastest growing death rates of any cancer. The purpose of the current study was to discover novel genome-wide aberrant DNA methylation patterns in HCC tumors that are predominantly HCV-related. Infinium HumanMethylation 450K BeadChip arrays were used to examine genome-wide DNA methylation profiles in 66 pairs of HCC tumor and adjacent non-tumor tissues. After Bonferroni adjustment, a total of 130,512 CpG sites significantly differed in methylation level in tumor compared with non-tumor tissues, with 28,017 CpG sites hypermethylated and 102,495 hypomethylated in tumor tissues. Absolute tumor/non-tumor methylation differences ≥ 20% were found in 24.9% of the hypermethylated and 43.1% of the hypomethylated CpG sites; almost 10,000 CpG sites have ≥ 30% DNA methylation differences. Most (60.1%) significantly hypermethylated CpG sites are located in CpG islands, with 21.6% in CpG shores and 3.6% in shelves. In contrast, only a small proportion (8.2%) of significantly hypomethylated CpG sites are situated in islands, while most are found in open sea (60.2%), shore (17.3%) or shelf (14.3%) regions. A total of 2,568 significant CpG sites (2,441 hypermethylated and 127 hypomethylated) covering 589 genes are located within 684 differentially methylated regions defined as regions with at least two significant CpG sites displaying > 20% methylation differences in the same direction within 250-bp. The top 500 significant CpG sites can significantly distinguish HCC tumor from adjacent tissues with one misclassification. Within adjacent non-tumor tissues, we also identified 75 CpG sites significantly associated with gender, 228 with HCV infection, 17,207 with cirrhosis, and 56 with both HCV infection and cirrhosis after multiple comparisons adjustment. Aberrant DNA methylation profiles across the genome were identified in tumor tissues from US HCC cases that are predominantly related to HCV infection. These results demonstrate the significance of aberrant DNA methylation in HCC tumorigenesis.

Small-bowel allograft biopsies in the management of small-intestinal and multivisceral transplant recipients: histopathologic review and clinical correlations

CONTEXT

Intestinal transplant has become a standard treatment option in the management of patients with irreversible intestinal failure. The histologic evaluation of small-bowel allograft biopsy specimens plays a central role in assessing the integrity of the graft. It is essential for the management of acute cellular and chronic rejection; detection of infections, particularly with respect to specific viruses (cytomegalovirus, adenovirus, Epstein-Barr virus); and immunosuppression-related lymphoproliferative disease.

OBJECTIVE

To provide a comprehensive review of the literature and illustrate key histologic findings in small-bowel biopsy specimen evaluation of patients with small-bowel or multivisceral transplants.

DATA SOURCES

Literature review using PubMed (US National Library of Medicine) and data obtained from national and international transplant registries in addition to case material at Columbia University, Presbyterian Hospital, and Mount Sinai Medical Center, New York, New York.

CONCLUSIONS

Key to the success of small-bowel transplantation and multivisceral transplantation are the close monitoring and appropriate clinical management of patients in the posttransplant period, requiring coordinated input from all members of the transplant team with the integration of clinical, laboratory, and histopathologic parameters.

Small-Bowel Allograft Biopsies in the Management of Small-Intestinal and Multivisceral Transplant Recipients: Histopathologic Review and Clinical Correlations

Context.—Intestinal transplant has become a standard treatment option in the management of patients with irreversible intestinal failure. The histologic evaluation of small-bowel allograft biopsy specimens plays a central role in assessing the integrity of the graft. It is essential for the management of acute cellular and chronic rejection; detection of infections, particularly with respect to specific viruses (cytomegalovirus, adenovirus, Epstein-Barr virus); and immunosuppression-related lymphoproliferative disease.

Objective.—To provide a comprehensive review of the literature and illustrate key histologic findings in small-bowel biopsy specimen evaluation of patients with small-bowel or multivisceral transplants.

Data Sources.—Literature review using PubMed (US National Library of Medicine) and data obtained from national and international transplant registries in addition to case material at Columbia University, Presbyterian Hospital, and Mount Sinai Medical Center, New York, New York.

Conclusions.—Key to the success of small-bowel transplantation and multivisceral transplantation are the close monitoring and appropriate clinical management of patients in the posttransplant period, requiring coordinated input from all members of the transplant team with the integration of clinical, laboratory, and histopathologic parameters.

Small-bowel allograft biopsies in the management of small-intestinal and multivisceral transplant recipients: histopathologic review and clinical correlations

CONTEXT

Intestinal transplant has become a standard treatment option in the management of patients with irreversible intestinal failure. The histologic evaluation of small-bowel allograft biopsy specimens plays a central role in assessing the integrity of the graft. It is essential for the management of acute cellular and chronic rejection; detection of infections, particularly with respect to specific viruses (cytomegalovirus, adenovirus, Epstein-Barr virus); and immunosuppression-related lymphoproliferative disease.

OBJECTIVE

To provide a comprehensive review of the literature and illustrate key histologic findings in small-bowel biopsy specimen evaluation of patients with small-bowel or multivisceral transplants.

DATA SOURCES

Literature review using PubMed (US National Library of Medicine) and data obtained from national and international transplant registries in addition to case material at Columbia University, Presbyterian Hospital, and Mount Sinai Medical Center, New York, New York.

CONCLUSIONS

Key to the success of small-bowel transplantation and multivisceral transplantation are the close monitoring and appropriate clinical management of patients in the posttransplant period, requiring coordinated input from all members of the transplant team with the integration of clinical, laboratory, and histopathologic parameters.