[Show abstract][Hide abstract] ABSTRACT: Hirschsprung disease-associated enterocolitis (HAEC) leads to significant mortality and morbidity, but its pathogenesis remains unknown. Changes in the colonic epithelium related to goblet cells and the luminal mucus layer have been postulated to play a key role. Here we show that the colonic epithelium of both aganglionic and ganglionic segments are altered in patients and in mice with Hirschsprung disease (HSCR). Structurally, goblet cells were altered with increased goblet cell number and reduced intracellular mucins in the distal colon of biopsies from patients with HSCR. Endothelin receptor B (Ednrb) mutant mice showed increased goblet cell number and size and increased cell proliferation compared to wild-type mice in aganglionic segments, and reduced goblet cell size and number in ganglionic segments. Functionally, compared to littermates, Ednrb-/- mice showed increased transepithelial resistance, reduced stool water content and similar chloride secretion in the distal colon. Transcript levels of goblet cell differentiation factors SPDEF and Math1 were increased in the distal colon of Ednrb-/- mice. Both distal colon from Ednrb mice and biopsies from HSCR patients showed reduced Muc4 expression as compared to controls, but similar expression of Muc2. Particle tracking studies showed that mucus from Ednrb-/- mice provided a more significant barrier to diffusion of 200 nm nanoparticles as compared to wild-type mice. These results suggest that aganglionosis is associated with increased goblet cell proliferation and differentiation and subsequent altered surface mucus properties, prior to the development of inflammation in the distal colon epithelium. Restoration of normal goblet cell function and mucus layer properties in the colonic epithelium may represent a therapeutic strategy for prevention of HAEC.
PLoS ONE 05/2014; 9(6):e99944. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The KRAS oncogene influences angiogenesis, metastasis and chemoresistance in colorectal cancers (CRCs), and these processes are all enhanced in hypoxic conditions. To define functional activities of mutant KRAS in a hypoxic microenvironment, we first performed cDNA microarray experiments in isogenic DKs5 and DKO3 colon cancer cell lines that differ only by their expression of mutant KRAS (K-ras(D13) ). Adrenomedullin (ADM) was identified as one of the most significantly upregulated genes in DKs5 cells that express the KRAS oncogene in hypoxia (3.2-fold, p = 1.47 × 10(-5) ). Ectopic expression of mutant KRAS (K-ras(V12) ) in Caco-2 cells (K-ras(WT) ) induced ADM, whereas selective knockdown of mutant KRAS alleles (K-ras(D13) or K-ras(V12) ) in HCT116, DLD1 and SW480 colon cancer cells suppressed the expression of ADM in hypoxia. Knockdown of ADM in colon tumor xenografts blocked angiogenesis and stimulated apoptosis, resulting in tumor suppression. Furthermore, ADM also regulated colon cancer cell invasion in vitro. Among 56 patients with CRC, significantly higher expression levels of ADM were observed in samples harboring a KRAS mutation. Collectively, ADM is a new target of oncogenic KRAS in the setting of hypoxia. This observation suggests that therapeutic targets may differ depending upon the specific tumor microenvironment.
International Journal of Cancer 05/2014; 134(9):2041-50. · 6.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Endoscopic ampullectomy is increasingly performed in patients with familial adenomatous polyposis (FAP)-associated ampullary adenomas. We sought to define the procedure-associated morbidities and long-term outcomes.
We performed a retrospective chart review of patients with FAP who underwent endoscopic ampullectomy at two tertiary institutions between 1999 and 2010. The severity of duodenal polyposis was classified according to Spigelman's classification.
Of 26 FAP patients who underwent endoscopic ampullectomy, 21 arose in the setting of Spigelman's stage II duodenal polyposis. Adverse events associated with endoscopic ampullectomy included acute pancreatitis (19.2 %), abdominal pain (7.6 %), and bleeding (3.8 %). The mean resected adenoma size was 0.99 ± 0.34 cm. Three adenomas (12.0 %) contained foci of high-grade dysplasia. Follow-up data were available for 24 patients. The mean follow-up duration was 84.5 ± 36.2 months. Adenoma recurrence was observed in 14 patients (58.3 %; 14/24) at a mean of 38.3 months after initial ampullectomy. Adenomas ≥10 mm recurred more frequently than smaller adenomas (76.9 vs. 36.4 %; p = 0.002). Positive margins were not associated with higher recurrence rates. No cancers were observed during long-term follow-up. Three patients underwent a Whipple procedure, but none was performed for a recurrent ampullary adenoma.
Endoscopic ampullectomy in FAP can be performed safely. Because ampullary adenomas frequently recur after endoscopic ampullectomy, close surveillance is essential. Smaller tumors are less likely to recur, suggesting a benefit for early recognition of these lesions.
[Show abstract][Hide abstract] ABSTRACT: Diagnosing anal squamous cell carcinoma (SCC), which is often preceded by anal intraepithelial neoplasia (AIN), may be challenging in small biopsies. Cytokeratin 17 (CK17) is a basal/myoepithelial cell keratin induced in activated keratinocytes and associated with disease progression in SCC of the uterine cervix, esophagus, and oral cavity. We investigated the utility of CK17 in diagnosing invasion in anal squamous neoplastic lesions. Immunohistochemical staining for CK17 was evaluated in 11 AINs, 12 invasive SCCs, 8 invasive SCCs with basaloid features (BSCC), and 2 invasive pure basaloid carcinomas. The pattern of staining was scored as surface/central, peripheral/rim, diffuse, or absent. All cases of invasive SCC and BSCC stained positive for CK17. Eleven of 12 (92%) SCCs showed diffuse staining, and 1 of 12 (8%) showed peripheral staining. Six of 8 (75%) BSCCs showed diffuse staining, and 2 of 8 (25%) showed peripheral staining. Both pure basaloid carcinomas were negative for CK17. One of 11 (9%) AINs was diffusely positive for CK17; all other AINs had surface or absent CK17. Of the 6 patients with concurrent AIN and invasive carcinoma, superficial expression of CK17 was present in 1 AIN, whereas all invasive components showed diffuse staining. The sensitivity and specificity of CK17 for identifying invasion in SCC and BSCC was 100% and 91%, respectively. Peripheral or diffuse staining for CK17 is a useful marker of invasion in anal squamous neoplastic lesions. A potential pitfall in the utility of CK17 is that the pure basaloid variant of anal carcinoma is negative for CK17.
The American journal of surgical pathology 01/2014; 38(1):78-85. · 4.06 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background
Alterations in the PI3K pathway are prevalent in endometrial cancer due to PIK3CA mutation and loss of PTEN. We investigated the anti-tumor activity of the PI3K inhibitor NVP BKM-120 (BKM) as a single agent and in combination with standard cytotoxic chemotherapy in a human primary endometrial xenograft model.
NOD/SCID mice bearing xenografts of primary human tumors with and without PIK3CA gene mutations were divided into two and four arm cohorts with equivalent tumor volumes. BKM was administered alone and in combination with paclitaxel and carboplatin (P/C) and endometrial xenograft tumor volumes were assessed. Tumors from the BKM, P/C, P/C + BKM and vehicle treated mice were processed for determination of PI3K/AKT/mTOR pathway activation.
In both single agent experiments, BKM resulted in significant tumor growth suppression starting at days 5–10 compared to the linear growth observed in vehicle treated tumors (p < 0.04 in all experiments). Tumor resurgence manifested between days 14–25 (p < 0.03). When BKM was combined with P/C, this resistance pattern failed to develop in three separate xenograft lines (p < 0.05). Synergistic tumor growth suppression (p < 0.05) of only one xenograft tumor with no detected PIK3CA mutation was observed. Acute treatment with BKM led to a decrease in pAKT levels.
Independent of PIK3CA gene mutation, BKM mediated inhibition of the PI3K/AKT/mTOR pathway in endometrial tumors precludes tumor growth in a primary xenograft model. While a pattern of resistance emerges, this effect appears to be mitigated by the addition of conventional cytotoxic chemotherapy.
[Show abstract][Hide abstract] ABSTRACT: Context.-Basaloid squamous cell carcinoma (bSCC) is an uncommon variant of squamous cell carcinoma, which may overlap histologically with basal cell carcinoma with squamous metaplasia (BCCm). Objective.-To aid in the differentiation of these neoplasms using immunohistochemical staining because of the worse prognosis associated with bSCC. Design.-Using immunohistochemical techniques, we investigated BerEp4, cytokeratin 17 (CK17), and cytokeratin 14 (CK14) protein expression in 25 cases of bSCC (8 cutaneous [32%], 12 aerodigestive tract [48%], and 5 lymph node metastases [20%]) and 43 cases of BCCm (39 cutaneous [91%], and 4 metastases [9%]). An immunoreactivity score was assigned using the percentage of tumor cells staining and the pattern of expression. Interobserver agreement for 2 independent pathologists was assessed using a κ coefficient. Results.-The mean percentage of staining was significantly higher in BCCm, compared with bSCC (BerEp4, P = .006; CK17, P < .001; CK14, P < .001; unpaired t test), with 58% of BCCm cases (25 of 43) displaying diffuse staining for all markers, and nearly all (98%; 42 of 43) displaying diffuse staining for CK17 and CK14. In contrast, no bSCC cases (0%) displayed diffuse staining for all 3 markers, and only 8% (2 of 25) displayed diffuse staining for CK17 and CK14. High interobserver agreement was determined. Conclusions.-BerEp4 alone is unreliable for differentiation between BCCm and bSCC, and the addition of either CK14 or CK17 will augment the sensitivity and negative predictive value of BerEp4 staining in BCCm and bSCC diagnosis.
Archives of pathology & laboratory medicine 11/2013; 137(11):1591-8. · 2.78 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The transformation of colonic mucosal epithelium to adenocarcinoma requires progressive oncogene activation and tumor suppressor gene inactivation. Loss of chromosome 18q is common in colon cancer but not in precancerous adenomas. A few candidate tumor suppressor genes have been identified in this region, including CABLES1 at 18q11.2-12.1. This study investigates the role of CABLES1 in an in vivo mouse model of intestinal adenocarcinoma and in human colon cancer cell culture. Apc (Min/+) mice were crossed with mice harboring targeted inactivation of the Cables1 gene (Cables1 (-/-) ). The intestinal tumor burden and tumor expression of β-catenin and PCNA was compared in Cables1 (+/+) Apc (Min/+) and Cables1 (-/-) Apc (Min/+) mice. β-catenin activity in human colon cancer cells with CABLES1 inactivation and intestinal progenitor cell function in Cables1 (-/-) mice were assayed in vitro. The mean number of small intestinal tumors per mouse was 3.1 ± 0.6 in Cables1 (+/+) Apc (Min/+) mice, compared with 32.4 ± 3.5 in the Cables1 (-/-) Apc (Min/+) mice (p < 0.0001). Fewer colonic tumors were observed in Cables1 (+/+) Apc (Min/+) mice (mean 0.6 ± 0.1) compared with the Cables1 (-/-) Apc (Min/+) mice (mean 1.3 ± 0.3, p = 0.01). Tumors from Cables1 (-/-) Apc (Min/+) mice demonstrated increased nuclear expression of β-catenin and an increased number of PCNA-positive cells. In vitro studies revealed that CABLES1 deficiency increased β-catenin dependent transcription and increased intestinal progenitor cell activity. Loss of Cables1 enhances tumor progression in the Apc (Min/+) mouse model and activates the Wnt/β-catenin signaling pathway. Cables1 is a tumor suppressor gene on chromosome 18q in this in vivo mouse model and likely has a similar role in human colon cancer.
Cancer biology & therapy 05/2013; 14(7). · 3.29 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Profiling studies of mRNA and microRNA, particularly microarray-based studies, have been extensively used to create compendia of genes that are preferentially expressed in the immune system. In some instances, functional studies have been subsequently pursued. Recent efforts such as the Encyclopedia of DNA Elements have demonstrated the benefit of coupling RNA sequencing analysis with information from expressed sequence tags (ESTs) for transcriptomic analysis. However, the full characterization and identification of transcripts that function as modulators of human immune responses remains incomplete. In this study, we demonstrate that an integrated analysis of human ESTs provides a robust platform to identify the immune transcriptome. Beyond recovering a reference set of immune-enriched genes and providing large-scale cross-validation of previous microarray studies, we discovered hundreds of novel genes preferentially expressed in the immune system, including noncoding RNAs. As a result, we have established the Immunogene database, representing an integrated EST road map of gene expression in human immune cells, which can be used to further investigate the function of coding and noncoding genes in the immune system. Using this approach, we have uncovered a unique metabolic gene signature of human macrophages and identified PRDM15 as a novel overexpressed gene in human lymphomas. Thus, we demonstrate the utility of EST profiling as a basis for further deconstruction of physiologic and pathologic immune processes.
The Journal of Immunology 04/2013; · 5.52 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A 54-year-old man was admitted to this hospital because of recurrent diarrhea, vomiting, and weight loss. The initial episode of diarrhea occurred 2.5 years before admission. Diagnostic procedures were performed.
New England Journal of Medicine 02/2013; 368(8):757-65. · 54.42 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Pediatric follicular lymphoma (PFL) is a variant of follicular lymphoma (FL) presenting as localized lymphadenopathy in children. Unlike conventional adult FL, PFL typically does not recur or progress. Clear diagnostic criteria for PFL are lacking, and it is uncertain whether this indolent lymphoma is defined by age or may occur in adults. We analyzed 27 FL in patients < 40 years of age and found that all 21 cases that lacked a BCL2 gene abnormality (BCL2-N; P < .0001) and had > 30% Ki67 fraction (high proliferation index, HPI; P = .0007) were stage I and did not progress or recur; in comparison, all 6 cases with BCL2 rearrangement and/or PI < 30% were stage III/IV, and 5 of 6 recurred or progressed. In a separate cohort of 58 adult FL (≥ 18 years of age), all 13 BCL2-N/HPI cases were stage I, and none progressed or relapsed, whereas 11 of 15 stage I cases with BCL2 gene abnormality and/or LPI relapsed or progressed (P = .0001). The adult and pediatric BCL2-N/HPI FL cases had similar morphologic features. Our results confirm the highly indolent behavior of PFL and suggest that these are characterized by HPI and absence of BCL2 gene abnormality. PFL-like cases also occur in adults and are associated with indolent behavior in this patient population.
[Show abstract][Hide abstract] ABSTRACT: The diagnosis of infectious mononucleosis (acute Epstein-Barr virus (EBV) infection) is usually made on the basis of clinical and laboratory findings. However, an atypical clinical presentation occasionally results in a lymph node or tonsillar biopsy. The morphological features of EBV-infected lymphoid tissue can easily mimic lymphoma. Furthermore, the immunophenotype of the immunoblasts has not been well characterized. To assess the morphological spectrum of acute EBV infection and the utility of immunohistochemistry in diagnosing difficult cases that resemble lymphoma, we reviewed 18 cases of acute EBV infection submitted in consultation to our institution with an initial diagnosis of/or suspicion for lymphoma. Patients included nine male and nine female individuals with a median age of 18 years (range 9-69). Biopsies were obtained from lymph nodes (3/18) or Waldeyer's ring (15/18). Infectious mononucleosis was confirmed by monospot or serological assays in 72% of cases (13/18). All cases featured architectural distortion by a polymorphous infiltrate with an immunoblastic proliferation, sometimes forming sheets. Reed-Sternberg-like cells were present in 8/18 (44%) of the cases. Infiltrates were often accompanied by necrosis (10/18) and mucosal ulceration (6/15). The majority of immunoblasts in all cases were CD20+ B cells with a post-germinal center immunophenotype (strongly positive for MUM1/IRF4 (18/18), CD10- (18/18 negative) and BCL-6- (16/18 negative; 2/18 faint BCL-6 expression in <10% of immunoblasts)). Immunoblasts showed variable weak expression of BCL-2 and polyclonal expression of κ and λ immunoglobulin light chains in 81% cases. Reed-Sternberg-like cells in 8/8 cases were CD30+, CD15-, BOB.1+ and OCT-2+. In conclusion, an atypical lymphoid infiltrate with numerous MUM1+, CD10-, BCL-6- immunoblasts should raise the suspicion of a reactive process, such as infectious mononucleosis, and warrants additional consideration before a diagnosis of lymphoma is made.
Modern Pathology 05/2012; 25(8):1149-59. · 5.25 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: How adult tissue stem and niche cells respond to the nutritional state of an organism is not well understood. Here we find that Paneth cells, a key constituent of the mammalian intestinal stem-cell (ISC) niche, augment stem-cell function in response to calorie restriction. Calorie restriction acts by reducing mechanistic target of rapamycin complex 1 (mTORC1) signalling in Paneth cells, and the ISC-enhancing effects of calorie restriction can be mimicked by rapamycin. Calorie intake regulates mTORC1 in Paneth cells, but not ISCs, and forced activation of mTORC1 in Paneth cells during calorie restriction abolishes the ISC-augmenting effects of the niche. Finally, increased expression of bone stromal antigen 1 (Bst1) in Paneth cells—an ectoenzyme that produces the paracrine factor cyclic ADP ribose—mediates the effects of calorie restriction and rapamycin on ISC function. Our findings establish that mTORC1 non-cell-autonomously regulates stem-cell self-renewal, and highlight a significant role of the mammalian intestinal niche in coupling stem-cell function to organismal physiology.
[Show abstract][Hide abstract] ABSTRACT: Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) lymphoma is a mature B-cell neoplasm that typically follows an indolent clinical course. Amyloid deposition associated with MALT lymphoma is uncommon. We describe the clinical and pathologic features of 20 cases of MALT lymphoma and associated amyloid deposition across diverse primary sites. Frozen section immunofluorescence performed on 4 cases suggests that these deposits are a localized form of AL amyloid. Clinical follow-up was available for 15 patients. Amyloid deposits distant from the initial site occurred in 5 cases, always at sites also involved by the underlying lymphoma. No definitive evidence of systemic amyloidosis affecting the heart, kidneys, or liver was present in any patient. Given the generally indolent clinical behavior of MALT lymphomas with associated amyloid, we do not recommend extensive follow-up testing for systemic amyloidosis or more aggressive therapy than would be indicated for other MALT lymphomas of similar clinical stage.
American Journal of Clinical Pathology 01/2012; 137(1):51-64. · 2.88 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Microsatellite instability (MSI) has been reported in various tumors, with colon cancer as the prototype. However, little is known about MSI in Barrett esophagus (BE)-associated adenocarcinoma. Thus, the aim of this study was to compare the clinicopathologic and molecular features of BE-associated adenocarcinomas with and without MSI. The study cohort consisted of 76 patients with BE-associated adenocarcinomas (66 male, 10 female), with a mean age of 65.1 years. Immunohistochemistry (IHC) for MLH1, MSH2, MSH6, PMS2, and CD3 and in situ hybridization for Epstein-Barr virus-encoded RNA were performed. MLH1 and PMS2 expression was lost by IHC in 5 cases (6.6%); of these, 5 showed high-level MSI (MSI-H) by polymerase chain reaction assay, and 4 showed hMLH1 promoter methylation. Histologically, tumors with MSI-H were heterogenous and included conventional adenocarcinomas with tumor-infiltrating lymphocytes (n=1), medullary carcinoma (n=2), signet ring cells (n=1), and signet ring cell and mucinous components (n=1). Compared with tumors negative for MSI by IHC, BE-associated adenocarcinomas with MSI-H were associated with older patient age (P=0.0060), lymphovascular invasion (P=0.027), and significantly larger numbers of tumor-infiltrating lymphocytes (P<0.0001). However, there was no statistical difference in overall survival between the 2 groups (P=0.285). In conclusion, MSI-H is uncommon in BE-associated adenocarcinomas, but is associated with clinicopathologic features fairly similar to sporadic microsatellite unstable colorectal cancers. Given the growing evidence that indicates lack of benefits from adjuvant therapy with fluorouracil in the colonic counterpart, it may be important to identify MSI-H in BE-associated adenocarcinomas.
The American journal of surgical pathology 03/2011; 35(5):647-55. · 4.06 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In vitro studies have suggested that the Cables1 gene regulates epithelial cell proliferation, whereas other studies suggest a role in promoting neural differentiation. In efforts to clarify the functions of Cables1 in vivo, we conducted gain- and loss-of-function studies targeting its ortholog (cables1) in the zebrafish embryo. Similar to rodents, zebrafish cables1 mRNA expression is detected most robustly in embryonic neural tissues. Antisense knockdown of cables1 leads to increased numbers of apoptotic cells, particularly in brain tissue, in addition to a distinct behavioral phenotype, characterized by hyperactivity in response to stimulation. Apoptosis and the behavioral abnormality could be rescued by co-expression of a morpholino-resistant cables1 construct. Suppression of p53 expression in cables1 morphants partially rescued both apoptosis and the behavioral phenotype, suggesting that the phenotype of cables1 morphants is due in part to p53-dependent apoptosis. Alterations in the expression patterns of several neural transcription factors were observed in cables1 morphants during early neurulation, suggesting that cables1 is required for early neural differentiation. Ectopic overexpression of cables1 strongly disrupted embryonic morphogenesis, while overexpression of a cables1 mutant lacking the C-terminal cyclin box had little effect, suggesting functional importance of the cyclin box. Lastly, marked reductions in p35, but not Cdk5, were observed in cables1 morphants. Collectively, these data suggest that cables1 is important for neural differentiation during embryogenesis, in a mechanism that likely involves interactions with the Cdk5/p35 kinase pathway.
Molecular Reproduction and Development 01/2011; 78(1):22-32. · 2.81 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Recent evidence links aberrant activation of Hedgehog (Hh) signaling with the pathogenesis of several cancers including medulloblastoma, basal cell, small cell lung, pancreatic, prostate and ovarian. This investigation was designed to determine if inhibition of this pathway could inhibit serous ovarian cancer growth.
We utilized an in vivo pre-clinical model of serous ovarian cancer to characterize the anti-tumor activity of Hh pathway inhibitors cyclopamine and a clinically applicable derivative, IPI-926. Primary human serous ovarian tumor tissue was used to generate tumor xenografts in mice that were subsequently treated with cyclopamine or IPI-926.
Both compounds demonstrated significant anti-tumor activity as single agents. When IPI-926 was used in combination with paclitaxel and carboplatinum (T/C), no synergistic effect was observed, though sustained treatment with IPI-926 after cessation of T/C continued to suppress tumor growth. Hh pathway activity was analyzed by RT-PCR to assess changes in Gli1 transcript levels. A single dose of IPI-926 inhibited mouse stromal Gli1 transcript levels at 24 hours with unchanged human intra-tumor Gli1 levels. Chronic IPI-926 therapy for 21 days, however, inhibited Hh signaling in both mouse stromal and human tumor cells. Expression data from the micro-dissected stroma in human serous ovarian tumors confirmed the presence of Gli1 transcript and a significant association between elevated Gli1 transcript levels and worsened survival.
IPI-926 treatment inhibits serous tumor growth suggesting the Hh signaling pathway contributes to the pathogenesis of ovarian cancer and may hold promise as a novel therapeutic target, especially in the maintenance setting.
PLoS ONE 01/2011; 6(11):e28077. · 3.53 Impact Factor