Lan Peng

Nuclear factor of activated T-cells (NFAT) rescues osteoclastogenesis in precursors lacking c-Fos.

Osteoclasts are specialized macrophages that resorb bone. Mice lacking the AP-1 component c-Fos are osteopetrotic because of a lack of osteoclast differentiation and show an increased number of macrophages. The nature of the critical function of c-Fos in osteoclast differentiation is not known. Microarray analysis revealed that Nfatc1, another key regulator of osteoclastogenesis, was down-regulated in Fos-/- osteoclast precursors. Chromatin immunoprecipitation assay showed that c-Fos bound to the Nfatc1 and Acp5 promoters in osteoclasts. In vitro promoter analyses identified nuclear factor of activated T-cells (NFAT)/AP-1 sites in the osteoclast-specific Acp5 and Calcr promoters. Moreover, in Fos-/- precursors gene transfer of an active form of NFAT restored transcription of osteoclast-specific genes in the presence of receptor activator of the NF-κB ligand (RANKL), rescuing bone resorption. In the absence of RANKL, however, Fos-/- precursors were insensitive to NFAT-induced osteoclastogenesis unlike wild-type precursors. These data indicate that lack of Nfatc1 expression is the cause of the differentiation block in Fos-/- osteoclast precursors and that transcriptional induction of Nfatc1 is a major function of c-Fos in osteoclast differentiation.

Histologic tumor involvement of superior mesenteric vein/portal vein predicts poor prognosis in patients with stage II pancreatic adenocarcinoma treated with neoadjuvant chemoradiation

Studies have shown that superior mesenteric vein (SMV)/portal vein (PV) resection with pancreaticoduodenectomy (PD) is safe and feasible for patient with pancreatic adenocarcinoma (PAC). However, the prognostic significance of tumor involvement of the resected vein in patients who received neoadjuvant therapy is unclear.

A solitary hyperfunctioning thyroid nodule harboring thyroid carcinoma: review of the literature

Hyperfunctioning nodules of the thyroid are thought to only rarely harbor thyroid cancer, and thus are infrequently biopsied. Here, we present the case of a patient with a hyperfunctioning thyroid nodule harboring thyroid carcinoma and, using MEDLINE literature searches, set out to determine the prevalence of and characteristics of malignant “hot” nodules as a group. Historical, biochemical and radiologic characteristics of the case subjects and their nodules were compared to those in cases of benign hyperfunctioning nodules. A literature review of surgical patients with solitary hyperfunctioning thyroid nodules managed by thyroid resection revealed an estimated 3.1% prevalence of malignancy. A separate literature search uncovered 76 cases of reported malignant hot thyroid nodules, besides the present case. Of these, 78% were female and mean age at time of diagnosis was 47 years. Mean nodule size was 4.13 ± 1.68 cm. Laboratory assessment revealed T3 elevation in 76.5%, T4 elevation in 51.9%, and subclinical hyperthyroidism in 13% of patients. Histological diagnosis was papillary thyroid carcinoma (PTC) in 57.1%, follicular thyroid carcinoma (FTC) in 36.4%, and Hurthle cell carcinoma in 7.8% of patients. Thus, hot thyroid nodules harbor a low but non-trivial rate of malignancy. Compared to individuals with benign hyperfunctioning thyroid nodules, those with malignant hyperfunctioning nodules are younger and more predominantly female. Also, FTC and Hurthle cell carcinoma are found more frequently in hot nodules than in general. We were unable to find any specific characteristics that could be used to distinguish between malignant and benign hot nodules.

High levels of nucleolar expression of nucleolin are associated with better prognosis in patients with stage II pancreatic ductal adenocarcinoma

Purpose: Nucleolin is a major nucleolar protein that has been shown to be overexpressed in rapidly dividing cells and plays an essential role in cell proliferation and survival. However, the expression and significance of nucleolin in pancreatic ductal adenocarcinoma (PDA) have not been studied. Experimental Design: We used a tissue microarray consisting of 1.0-mm cores of tumor and paired nonneoplastic pancreatic tissue from 69 pancreaticoduodenectomy specimens with stage II PDA. Nucleolin expression was evaluated by immunohistochemistry and scored quantitatively by image analysis. Nucleolin expression was classified as nucleolin-high or nucleolin-low using the median nucleolin labeling index of 3.5% as cutoff. Staining results were correlated with clinicopathologic features and survival. Results: Both PDAs and PDA cell lines showed nucleolar staining for nucleolin. Nucleolin expression was higher in PDAs and PDA cell lines than in nonneoplastic ductal epithelial cells. Among the 69 stage II PDAs, 34 (49%) were nucleolin-high. The median overall survival was 65.2 ± 16.3 months for patients who had nucleolin-high PDAs compared with 19.5 ± 3.3 months for patients whose tumors were nucleolin-low (P = 0.03, log-rank method). No significant correlation between nucleolin expression and other clinicopathologic parameters was found. In multivariate analysis, nucleolin expression was a prognostic factor for overall survival in patients with stage II PDA independent of patients age, gender, tumor size, differentiation, and lymph node status. Conclusions: Nucleolin was overexpressed in PDAs and PDA cell lines. A high level of nucleolar expression of nucleolin was an independent prognostic marker for better survival for patients with stage II PDAs. Clin Cancer Res; 16(14); 3734–42. ©2010 AACR.

Vaccination as a triggering event for autoimmune hepatitis.

The pathogenesis of autoimmune hepatitis entails complex interactions between triggering factors, autoantigens, genetic predisposition, and immunoregulatory networks. Implicated triggering factors are numerous and include toxins, medications, and infectious agents. In this article, we present a unique case of a 31-year-old woman with severe autoimmune hepatitis apparently abruptly triggered by vaccination. All evidence suggests this was an idiosyncratic response to either hepatitis A or yellow fever vaccination.

Pancreatic Neuroendocrine Tumors: Signal Pathways and Targeted Therapies

Pancreatic neuroendocrine tumors (PNETs) are rare but are well understood to cover a broad spectrum of clinical presentation, tumor biology and prognosis. More than 60% of PNETs are diagnosed at advanced disease stage and are ineligible for surgical resection. Prior to 2011, streptozocin was the only approved agent for unresectable advanced PNETs. In recent years, breakthroughs in signal pathway research have led to the identification of new therapeutic targets and agents directed at the molecular level. In 2011, two new targeted therapeutic agents, sunitinib and everolimus, were approved by the Food and Drug Administration (FDA). Sunitinib is an inhibitor of multiple tyrosine kinases, and everolimus is an inhibitor of the mammalian target of rapamycin (mTOR) pathway. This review discusses the major signaling pathways that are frequently mutated or deregulated in PNETs, and the implications of molecular alterations for PNET therapy. Biologic therapy through targeting relevant pathways represents a promising approach in the therapy of advanced and unresectable PNETs.

Targeted gene repair in mammalian cells using chimeric oligonucleotides.

In the past several years, significant advances in the area of genome modification have taken place. In some cases, the objective has been to block RNA synthesis and change developmental progression (1), while in other cases more permanent alteration at the chromosomal level has been attempted (2). These types of approaches seek not to replace traditional protocols of gene knock-out, gene knock-in or gene replacement, but rather augment them, adding to the arsenal of techniques available to workers who wish to study functional aspects of gene expression. In fact, since the strategies for creating mouse knock-outs first became available, relatively little improvement in the rate of success has occurred.

Collision tumor in form of primary adenocarcinoma and neuroendocrine carcinoma of the duodenum

Collision tumor is a rare phenomenon characterized by coexistence of completely distinct and independent tumors at the same body location. Collision tumors have been reported in different sites. However, they are extremely uncommon in the duodenum. We report the case of a 52-year old man with a collision tumor in the third portion of the duodenum with two distinct tumors of primary adenocarcinoma and neuroendocrine carcinoma, and both tumors coexisting within a single metastatic lymph node. Immunohistochemistry studies were performed to conclude that this was a case of collision cancer. To the best of our knowledge, this is the first collision tumor case reported to date at this location, and the first report of lymph node with a collision metastasis from a collision tumor. Such tumor is very rare and may thus provide diagnostic challenges. This report also provides a review of other cases on duodenal collision tumors.

Pasireotide for the treatment of refractory hypoglycaemia from malignant insulinoma

Dear Editor, Insulinomas are rare, usually solitary benign tumours. The presence of metastases defines malignant insulinomas.1 Medical therapy primarily treats symptomatic hypoglycaemia, alleviates symptoms and improves the quality of life in affected individuals. While diazoxide is used as firstline therapy, the incomplete response rate and complications associated with diazoxide provide a role for somatostatin analogues in difficulttotreat hypoglycaemia.

Synthesis, Characterization, and In Vitro and In Vivo Evaluations of 4-(N)-Docosahexaenoyl 2′, 2′-Difluorodeoxycytidine with Potent and Broad-Spectrum Antitumor Activity

In this study, a new compound, 4-(N)-docosahexaenoyl 2′, 2′-difluorodeoxycytidine (DHA-dFdC), was synthesized and characterized. Its antitumor activity was evaluated in cell culture and in mouse models of pancreatic cancer. DHA-dFdC is a poorly soluble, pale yellow waxy solid, with a molecular mass of 573.3 Da and a melting point of about 96°C. The activation energy for the degradation of DHA-dFdC in an aqueous Tween 80–based solution is 12.86 kcal/mol, whereas its stability is significantly higher in the presence of vitamin E. NCI-60 DTP Human Tumor Cell Line Screening revealed that DHA-dFdC has potent and broad-spectrum antitumor activity, especially in leukemia, renal, and central nervous system cancer cell lines. In human and murine pancreatic cancer cell lines, the IC50 value of DHA-dFdC was up to 105-fold lower than that of dFdC. The elimination of DHA-dFdC in mouse plasma appeared to follow a biexponential model, with a terminal phase t1/2 of about 58 minutes. DHA-dFdC significantly extended the survival of genetically engineered mice that spontaneously develop pancreatic ductal adenocarcinoma. In nude mice with subcutaneously implanted human Panc-1 pancreatic tumors, the antitumor activity of DHA-dFdC was significantly stronger than the molar equivalent of dFdC alone, DHA alone, or the physical mixture of them (1:1, molar ratio). DHA-dFdC also significantly inhibited the growth of Panc-1 tumors orthotopically implanted in the pancreas of nude mice, whereas the molar equivalent dose of dFdC alone did not show any significant activity. DHA-dFdC is a promising compound for the potential treatment of cancers in organs such as the pancreas.