Urs von Holzen

Absence of myeloperoxidase and CD8 positive cells in colorectal cancer infiltrates identifies patients with severe prognosis

Colorectal cancer (CRC) infiltration by cells expressing myeloperoxidase (MPO) or CD8 positive T lymphocytes has been shown to be independently associated with favorable prognosis. We explored the relationship occurring between CD8+ and MPO+ cell CRC infiltration, its impact on clinical-pathological features and its prognostic significance in a tissue microarray (TMA) including 1,162 CRC. We observed that CRC showing high MPO+ cell infiltration are characterized by a prognosis as favorable as that of cancers with high CD8+ T cell infiltration. However, MPO+ and CD8+ CRC infiltrating cells did not synergize in determining a more favorable outcome, as compared with cancers showing MPOhigh/CD8low or MPOlow/CD8high infiltrates. Most importantly, we identified a subgroup of CRC with MPOlow/CD8low tumor infiltration characterized by a particularly severe prognosis. Intriguingly, although MPO+ and CD8+ cells did not co-localize in CRC infiltrates, an increased expression of TIA-1 and granzyme-B was detectable in T cells infiltrating CRC with high MPO+ cell density.

A surprise cell of origin for Barrett's esophagus.

Barrett’s esophagus is a metaplasia of the distal esophagus that is the only recognized precursor of esophageal adenocarcinoma. Despite a characteristic histology, the pathogenesis of Barrett’s has remained obscure. A recent paper from the laboratories of Wa Xian and Frank McKeon presents evidence for a novel cell of origin of Barrett’s. Their work is based on studies of mice engineered to lack the squamous epithelial stem cell survival factor p63. These mice develop a metaplasia of the proximal stomach and esophagus that harbors substantial histological and molecular features of Barrett’s. The metaplasia appears to form from embryonic progenitor cells that normally persists post-natally only at the squamo-columnar junction. Moreover, in their model, the metaplasia is initiated not by mutation but by reduced competition between these cells and squamous epithelial cells.

A case of cecal volvulus mimicking Ogilvie Syndrome in a hospitalized patient with a pelvis fracture

Introduction Cecal volvulus and ogilvie syndrome are two entities which may display similar clinical presentation but require different treatment approaches. Presentation of case An 84-year old male patient admitted for conservative treatment of a pelvis fracture, complained of abdominal cramps and flatulence on the third hospitalization day. Abdominal radiographs arose suspicion of cecal volvulus. The diagnosis was ruled out on the CT scan but however was later confirmed by an exploratory laparotomy. Discussion The management of cecal volvulus requires prompt (emergency) surgical intervention while Ogilvie syndrome can be principally managed with conservative treatment. Our patients profile was typical for both entities. The absence of air throughout all colonic segments including the rectosigmoid on plain abdominal radiographs seems to be the most important sign in the exclusion of the Ogilvie syndrome diagnosis. Conclusion Cecal volvulus and Ogilvie syndrome display overlapping clinical features at their time of presentation and need to be carefully distinguished. By uncertainty, an exploratory laparotomy should always be performed, in view of the reported high mortality rate of cecal volvulus if surgery is delayed.

Superior Therapeutic Efficacy of Nanoparticle Albumin Bound Paclitaxel Over Cremophor-Bound Paclitaxel in Experimental Esophageal Adenocarcinoma

Esophageal adenocarcinoma (EAC) is the fastest growing cancer in the western world and the overall 5 year survival rate of EAC is below 20%. Most patients with EAC present with locally advanced or widespread metastatic disease, where current treatment is largely ineffective. Therefore, new therapeutic approaches are urgently needed. Nanoparticle albumin-bound paclitaxel (nab-paclitaxel) is a novel albumin-stabilized, cremophor-free and water soluble nanoparticle formulation of paclitaxel, and the potential role of nab-paclitaxel has not been tested yet in experimental EAC. Here we tested the antiproliferative and antitumor efficacy with survival advantage of nab-paclitaxel as monotherapy and in combinations in in-vitro, and in murine subcutaneous xenograft and peritoneal metastatic survival models of human EAC. Nab-paclitaxel significantly inhibited in-vitro cell proliferation with higher in-vivo antitumour efficacy and survival benefit compared to paclitaxel or carboplatin treatments both in mono- and combination therapies. Nab-paclitaxel treatment increased expression of mitotic-spindle associated phospho-stathmin, decreased expression of proliferative markers and enhanced apoptosis. This study demonstrates that nab-paclitaxel had stronger antiproliferative and antitumor activity in experimental EAC than the current standard chemotherapeutic agents which supports the rationale for its clinical use in EAC.

Abstract 4826: Synergistic effects of foretinib with lapatinib in MET and HER2 co-activated experimental esophageal adenocarcinoma

Introduction: Recent studies have demonstrated that HER2 and MET receptor tyrosine kinases are co-overexpressed in a subset esophageal adenocarcinoma (EAC). We therefore studied the usefulness of combining HER2 and MET targeting by small-molecule inhibitors foretinib and lapatinib both in-vitro and in-vivo models of experimental EAC. Methods: In this study we first characterized MET and HER2 activation in a panel of human EAC cell lines and the differential susceptibility of these EAC cell lines to single agents or combinations of foretinib, a multi-kinase MET inhibitor, with HER2 targeted agent lapatinib. We evaluated the levels of phosphorylation status of MET and HER2 proteins using western blot in EAC cell lines. Foretinib and lapatinib, as single agent or in combination were tested for effect on cell growth as detected by WST-1 assay and on cell apoptosis as detected by western blot of cleavage of caspase 3 and poly ADP ribose polymerase (PARP). In addition, we explored the antitumor efficacy with survival advantage following foretinib and lapatinib mono and combination therapies for two weeks in murine subcutaneous xenograft and peritoneal metastatic survival models of human EAC. Results: The OE33 EAC cell line with phosphorylation of both MET and HER2, demonstrated reduced sensitivity to foretinib and lapatinib when used as a single agent. The co-administration of foretinib and lapatinib effectively inhibited both MET and HER2 phosphorylation, synergistically inhibited cell growth and induced apoptosis, overcoming single agent resistance. In the OE19 EAC cell line with only HER2 phosphorylation and the ESO51 EAC cell line with only MET phosphorylation, profound cell growth inhibition with induction of apoptosis was observed in response to single agent foretinib and lapatinib, respectively, with lack of enhanced growth inhibition when the two drugs were combined. Foretinib in combination with lapatinib treatment resulted in significantly higher antitumor efficacy and survival benefit compared with foretinib or lapatinib treatment alone. In subcutaneous xenografts using OE33 cells, average net tumor growth after two weeks in different therapy groups was 247.83 mm3 in control, 216.71 mm3 after foretinib (p=0.49), 239.68 mm3 after lapatinib (p=0.74), and 108.06 mm3 after foretinib plus lapatinib (p=0.0011). In the OE33 survival model there was a significant increase in median animal survival after two weeks foretinib plus lapatinib treatment (71 days) compared to control (60 days, p=0.0021), to foretinib therapy (63 days, p=0.0019) or to lapatinib (61 days, p=0.0019) therapy. Conclusion: These data suggest that combination therapy with foretinib and lapatinib should be tested as a treatment option for HER2 positive patients with MET-overexpressing EAC. Therefore, this combination therapy could be a novel treatment strategy for EAC with MET and HER co-activation. Citation Format: Md Sazzad Hassan, Fiona Williams, Niranjan Awasthi, Margaret A. Schwarz, Roderich E. Schwarz, Urs von Holzen. Synergistic effects of foretinib with lapatinib in MET and HER2 co-activated experimental esophageal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4826.

Abstract 1258: Therapeutic potential of the cyclin- dependent kinase inhibitor on c-Myc overexpressing esophageal adenocarcinoma

Introduction: Esophageal adenocarcinoma (EAC) is now the fastest growing cancer in the western world and most EAC patients present with widespread metastatic disease, where current treatment is largely ineffective. Therefore, new therapeutic approaches are urgently needed. The transcription factor proto-oncogene c-Myc is a potent activator of tumorigenesis. Tumors with elevated c-Myc expression often exhibit highly aggressive phenotype. c-Myc amplification has been shown to be frequent in esophageal adenocarcinoma and has been implicated in Barrett9s carcinogenesis. Emerging data suggests that synthetic lethal interactions between c-Myc pathway activation and small molecules inhibition involved in cell cycle signaling can be therapeutically exploited to preferentially kill tumor cells. In this study, we therefore investigated whether exploiting a synthetic-lethal approach dependent on elevated c-Myc signaling is effective in treating esophageal cancer with a cyclin-dependent kinase (CDK) inhibitor flavopiridol. Methods: Western blot analysis was done to see the expression of c-Myc and apoptotic signaling pathways in a panel of nine esophageal cancer cell lines. c-Myc overexpression and knockdown were performed using both genetic and novel chemical approaches. Cell viability assays were performed in 96-well plates using the colorimetric WST-1 reagent. Esophageal cancer tumors growth was measured in xenograft and a novel peritoneal disseminated metastatic survival model of immunodeficient mice. Results: Western blot analysis revealed frequent overexpression of c-Myc in EAC cell lines. In this panel of esophageal cancer cell lines tested more than 70% of EAC cell lines showed overexpression of c-Myc. When we tested these cell lines for their ability to form xenograft tumor and peritoneal dissemination, c-Myc overexpression correlated with accelerated EAC tumor growth in xenograft and peritoneal disseminated metastatic survival model of NOD/SCID mice. The xenograft tumor growth rate and formation rate of peritoneal cancer after injection of 5 million cells were highest in OE19 EAC cell line which showed the highest c-Myc expression. In addition, median animal survival with peritoneal dissemination was lowest for OE19 (55 days) whereas OACM5.1 C EAC cell line which had the lowest c-Myc expression didn9t form any peritoneal tumor. EAC cell lines with elevated c-Myc expression are preferentially more sensitive to induction of apoptosis by CDK inhibitor flavopiridol compared to EAC cell lines with lower c-Myc expression. When we tested the role of c-Myc expression by upregulation/downregulation in this apoptotic effect we found that this effect is very much dependent on c-Myc expression. Conclusion: These results indicate that CDK inhibitor alone or in combination with other cytotoxic or targeted agents can be a potential therapy for c-Myc overexpressing EAC. Citation Format: Sazzad Hassan, Niranjan Awasthi, Margaret A. Schwarz, Roderich E. Schwarz, Urs V. Holzen. Therapeutic potential of the cyclin- dependent kinase inhibitor on c-Myc overexpressing esophageal adenocarcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1258.

Abstract 4031: Different expression of programmed death 1 (PD1) and its ligand (PD-L1) in esophageal and gastric cancer

Background: Prognosis of gastric and esophageal cancer remains poor. Improvements in gastric and esophageal cancer treatments are urgently needed. Programmed cell death 1 receptor (PD1) and its ligand 1 (PD-L1) are known to interact with T cells promoting epithelial cancer tolerance. Several therapeutic monoclonal antibodies blocking this interaction are reaching the clinical praxis. Therefore it is relevant to investigate the role of these biomarkers in different types of malignancy. Methods: Four different copies of tissue microarrays (TMA), each including healthy mucosa (n = 74) and a total of 241 clinically annotated malignancies of the esophagus (n = 80) and stomach (n = 161) were constructed and stained with PD1, PD-L1, and CD8 specific reagents. Results: Interestingly, only two cancer samples out of the 241 specimens investigated weakly expressed PD-L1. None of the normal mucosa epithelial cells expressed PD-L1. Stromal PD1 expression correlated with infiltration by CD8+ lymphocytes (rho = 0.4; P Conclusion: In contrast to other epithelial cancers, PD-L1 expression was virtually absent in the investigated malignancies of the esophagus and stomach. PD1 expression in the stroma surrounding such malignancies correlated with intraepithelial presence of T-cells CD8+ expression, and with better prognosis in gastric cancer patients. Citation Format: Silvio Daster, Serenella Eppenberger-Castori, Raoul A. Droeser, Hannah M. Schaefer, Giulio C. Spagnoli, Luigi Terracciano, Luigi Tornillo, Urs von Holzen. Different expression of programmed death 1 (PD1) and its ligand (PD-L1) in esophageal and gastric cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4031.