Tyrosine 23 Phosphorylation-Dependent Cell-Surface Localization of Annexin A2 Is Required for Invasion and Metastases of Pancreatic Cancer

The aggressiveness of pancreatic ductal adenocarcinoma (PDA) is characterized by its high metastatic potential and lack of effective therapies, which is the result of a lack of understanding of the mechanisms involved in promoting PDA metastases. We identified Annexin A2 (ANXA2), a member of the Annexin family of calcium-dependent phospholipid binding proteins, as a new molecule that promotes PDA invasion and metastases. We found ANXA2 to be a PDA-associated antigen recognized by post-treatment sera of patients who demonstrated prolonged survival following treatment with a PDA-specific vaccine. Cell surface ANXA2 increases with PDA development and progression. Knockdown of ANXA2 expression by RNA interference or blocking with anti-ANXA2 antibodies inhibits in vitro invasion of PDA cells. In addition, post-vaccination patient sera inhibits in vitro invasion of PDA cells, suggesting that therapeutic anti-ANXA2 antibodies are induced by the vaccine. Furthermore, cell-surface localization of ANXA2 is tyrosine 23 phosphorylation-dependent; and tyrosine 23 phosphorylation is required for PDA invasion. We demonstrated that tyrosine 23 phosphorylation resulting in surface expression of ANXA2 is required for TGFβ-induced, Rho-mediated epithelial-mesenchymal transition (EMT), linking the cellular function of ANXA2 which was previously shown to be associated with small GTPase-regulated cytoskeletal rearrangements, to the EMT process in PDA. Finally, using mouse PDA models, we showed that shRNA knock-down of ANXA2, a mutation at tyrosine 23, or anti-ANXA2 antibodies, inhibit PDA metastases and prolong mouse survival. Thus, ANXA2 is part of a novel molecular pathway underlying PDA metastases and a new target for development of PDA therapeutics

Interleukin 6 increases production of cytokines by colonic innate lymphoid cells in mice and patients with chronic intestinal inflammation

Background & Aims: Innate lymphoid cells (ILCs) are a heterogeneous group of mucosal inflammatory cells that participate in chronic intestinal inflammation. We investigated the role of interleukin 6 (IL6) in inducing activation of ILCs in mice and in human beings with chronic intestinal inflammation. Methods: ILCs were isolated from colons of Tbx21-/- × Rag2-/- mice (TRUC), which develop colitis; patients with inflammatory bowel disease (IBD); and patients without colon inflammation (controls). ILCs were characterized by flow cytometry; cytokine production was measured by enzyme-linked immunosorbent assay and cytokine bead arrays. Mice were given intraperitoneal injections of depleting (CD4, CD90), neutralizing (IL6), or control antibodies. Isolated colon tissues were analyzed by histology, explant organ culture, and cell culture. Bacterial DNA was extracted from mouse fecal samples to assess the intestinal microbiota. Results: IL17A- and IL22-producing, natural cytotoxicity receptor-negative, ILC3 were the major subset of ILCs detected in colons of TRUC mice. Combinations of IL23 and IL1α induced production of cytokines by these cells, which increased further after administration of IL6. Antibodies against IL6 reduced colitis in TRUC mice without significantly affecting the structure of their intestinal microbiota. Addition of IL6 increased production of IL17A, IL22, and interferon-γ by human intestinal CD3-negative, IL7-receptor-positive cells, in a dose-dependent manner. Conclusions: IL6 contributes to activation of colonic natural cytotoxicity receptor-negative, CD4-negative, ILC3s in mice with chronic intestinal inflammation (TRUC mice) by increasing IL23- and IL1α-induced production of IL17A and IL22. This pathway might be targeted to treat patients with IBD because IL6, which is highly produced in colonic tissue by some IBD patients, also increased the production of IL17A, IL22, and interferon-γ by cultured human colon CD3-negative, IL7-receptor-positive cells

RET gene fusion and emergent Selpercatinib resistance in a calcitonin-rich neuroendocrine carcinoma: a case report

Metastatic lung neuroendocrine carcinomas provide diagnostic challenges in identifying the cell of origin. High level calcitonin expression is not pathognomonic for medullary thyroid cancer. Tumor mutation analysis may provide essential clues regarding tissue origin and treatment targets. Oncogenic RET gene fusions have been identified in non-small cell lung cancer and non-medullary thyroid cancers, whereas RET point mutations are the key genetic finding in both inherited and sporadic MTC. Patients who receive radiation for the treatment of other cancers have an increased risk of developing a second malignancy, including a neuroendocrine carcinoma. Herein, we present a case of calcitonin-rich neuroendocrine carcinoma emerging on a background of prior radiation and chemotherapy for the treatment of Hodgkin’s disease. Identification of a RET gene rearrangement (KIF5B-RET) led to initial successful treatment with selpercatinib, with eventual resistance associated with an activating mutation involving the MEK1 protein (MAP2K1 p. E102-I103 del) that led to relapse and progression of the disease

Syphilitic and lymphogranuloma venereum (LGV) proctocolitis clues to a frequently missed diagnosis

A rising incidence of syphilis and lymphogranuloma venereum (LGV) underscores the importance of recognizing these sexually transmitted infections (STI) in routine anocolonic biopsies. To increase awareness of their morphologic manifestations, we undertook a clinicopathologic study of our experience: syphilis (7 patients, 7 specimens), LGV (2 patients, 4 specimens), and syphilis/LGV (1 patient, 3 specimens). The diagnoses of all study specimens were confirmed with pertinent clinical studies. All study patients were human immunodeficiency virus positive, and all 9 with available history were men who have sex with men. The majority presented with bleeding (9), pain (6), and tenesmus (4). Ulcerations were the most common endoscopic abnormality (7), whereas mass lesions were confined to the syphilis group (4). None of the initial impressions included LGV, and syphilis was prospectively suggested only by pathologists (6 of 8) without the knowledge of clinical information and on the basis of morphology. Alternative impressions included condyloma acuminatum (3), inflammatory bowel disease (3), and malignancy (2), among others. All study specimens shared the following histologic core features: an intense lymphohistiocytic infiltrate with prominent plasma cells and lymphoid aggregates, only mild to moderate acute inflammation, minimal basal plasmacytosis and crypt distortion, and only rare granulomas and Paneth cell metaplasia. The spirochetes were focally demonstrated on a Treponema pallidum immunohistochemical stain (1) but not on silver stains (3). All patients with available follow-up data showed resolution of symptoms and imaging abnormalities after STI therapy (6). In summary, we report a unique pattern of STI proctocolitis consistently identified in patients with serologically confirmed syphilis and/or LGV infection; pertinent STI therapy leads to resolution of clinical abnormalities. This histologic pattern is important to recognize for timely treatment, for prevention of onward STI transmission, and to avoid the diagnostic pitfalls of inflammatory bowel disease or malignancy

Mesothelin expression in patients as a novel target in gastric cancer.

61 Background: Novel targets and therapeutics are of profound importance if we are to improve outcomes in gastric cancer. This study assessed the incidence of mesothelin expression in tumors of Western patients with gastric cancer. In addition, gastric cancer cell lines were then tested for their sensitivity to SS1(dsFv)PE38 (SS1P), a mesothelin-targeted immunotoxin. Methods: Tissue specimens from 127 patients with gastric or gastro-esophageal junction (GEJ) tumors were examined by immuno-histochemistry (IHC) for intensity of staining for mesothelin. Expression of HER2-neu, e-cadherin and c-Met were also assessed. Tumors were considered positive for mesothelin if moderate cytoplasmic/membranous or luminal staining was present in at least 10% of the cells. Gastric cancer cell lines were assessed for surface mesothelin expression by flow cytometry and the viability of cells treated with SS1P was measured. Results: Gastric and GEJ cancers were mesothelin positive in 64/127 tumors (50%) while only 9 tumors (7%) were Her2-neu IHC +3 positive and 8 tumors (6%) were c-Met positive (c-Met low 5% and c-Met high 1%). Mesothelin expression rates changed from stage I tumors to stage IV tumors (39% to 56% respectively). We found that both the AGS and MKN28 gastric cancer cell lines express mesothelin and are sensitive to the immunotoxin with EC50 values in the low picomolar range (0.4 and 0.3 ng/mL, respectively). Conclusions: Mesothelin is a cell surface glycoprotein that is expressed in 50% of resected gastric cancers. Gastric cancer cell lines were exquisitely sensitive to SS1P. The high expression of mesothelin and its sensitivity to the immunotoxin SS1P makes it an attractive tumor associated antigen for therapeutic targeting. Based on these observations clinical trials involving novel mesothelin targeted drugs in gastric cancer are currently in development