CSPG4 marks pericytes, undifferentiated precursors and tumor cells. We assessed whether the shed ectodomain of CSPG4 (sCSPG4) might circulate and reflect potential changes in CSPG4 tissue expression (pCSPG4) due to desmoplastic and malignant aberrations occurring in pancreatic tumors. Serum sCSPG4 was measured using ELISA in test (n?=?83) and validation (n?=?221) cohorts comprising donors (n?=?11+26) and patients with chronic pancreatitis (n?=?11+20) or neoplasms: benign (serous cystadenoma SCA, n?=?13+20), premalignant (intraductal dysplastic IPMNs, n?=?9+55), and malignant (IPMN-associated invasive carcinomas, n?=?4+14; ductal adenocarcinomas, n?=?35+86). Pancreatic pCSPG4 expression was evaluated using qRT-PCR (n?=?139), western blot analysis and immunohistochemistry. sCSPG4 was found in circulation, but its level was significantly lower in pancreatic patients than in donors. Selective maintenance was observed in advanced IPMNs and PDACs and showed a nodal association while lacking prognostic relevance. Pancreatic pCSPG4 expression was preserved or elevated, whereby neoplastic cells lacked pCSPG4 or tended to overexpress without shedding. Extreme pancreatic overexpression, membranous exposure and tissue(high)/sera(low)-discordance highlighted stroma-poor benign cystic neoplasm. SCA is known to display hypoxic markers and coincide with von-Hippel-Lindau and Peutz-Jeghers syndromes, in which pVHL and LBK1 mutations affect hypoxic signaling pathways. In vitro testing confined pCSPG4 overexpression to normal mesenchymal but not epithelial cells, and a third of tested carcinoma cell lines; however, only the latter showed pCSPG4-responsiveness to chronic hypoxia. siRNA-based knockdowns failed to reduce the malignant potential of either normoxic or hypoxic cells. Thus, overexpression of the newly established conditional hypoxic indicator, CSPG4, is apparently non-pathogenic in pancreatic malignancies but might mark distinct epithelial lineage and contribute to cell polarity disorders. Surficial retention on tumor cells renders CSPG4 an attractive therapeutic target. Systemic 'drop and restoration' alterations accompanying IPMN and PDAC progression indicate that the interference of pancreatic diseases with local and remote shedding/release of sCSPG4 into circulation deserves broad diagnostic exploration.
Erythropoietin (Epo) administration has been reported to have tumor-promoting effects in anemic cancer patients. We investigated the prognostic impact of endogenous Epo in patients with pancreatic ductal adenocarcinoma (PDAC).
Actinin-4 is an actin-bundling protein that probably has a tumor-promoting potential in several solid tumors. The present study analyzed the expression of actinin-4 in the pancreas, in localized and metastasized pancreatic ductal adenocarcinoma (PDAC), and the correlation with clinical outcome.
In over 70% of the cases, patients with curative surgery and adjuvant chemotherapy for pancreatic ductal adenocarcinoma (PDAC) develop recurrent tumors. The cancer stem cell (CSC) hypothesis suggests that CSCs are chemoresistant and enriched in recurrent tumors. This study analyzes tumorbiology, expression of the metastasis-promoting CXCR4 and actinin-4, and of the CSC marker CD133 in primary and recurrent PDAC. Twenty-six patients underwent resection for primary and recurrent PDAC and most developed tumor recurrence within 2 years. In 81% the histologic tumor grade was unchanged. Immunohistochemistry could be performed with 15 pairs of primary and recurrent PDAC. The mean Ki-67 proliferation index increased (P = 0.06). About 30% of tumor cells were positive for CXCR4 and almost all tumor cells expressed actinin-4, but there were neither significant changes in the expression levels in recurrent PDAC, nor specifically enhanced levels in metastases. The prominent CD133 pattern was an apical membrane staining of inflammatorily altered, non-neoplastic ductal structures equally observed in primary and recurrent PDAC. The membrane CD133 positivity was consistently absent in neoplastic PDAC cells. Cytoplasmic CD133 positivity was extremely rare (0.85 and 0.34 cells/cm(2) in primary and recurrent PDAC, respectively; P = 0.07). Tumor grade is mainly unchanged and the expression of CXCR4, actinin-4 and CD133 are not enhanced in recurrent PDAC. The apical membrane CD133 positivity of normal and inflammatorily altered ductal structures and its lack in tumor cells bring the role of CD133 as a specific CSC marker in PDAC into question.
Standard cancer cell lines do not model the intratumoural heterogeneity situation sufficiently. Clonal selection leads to a homogeneous population of cells by genetic drift. Heterogeneity of tumour cells, however, is particularly critical for therapeutically relevant studies, since it is a prerequisite for acquiring drug resistance and reoccurrence of tumours. Here, we report the isolation of a highly tumourigenic primary pancreatic cancer cell line, called JoPaca-1 and its detailed characterization at multiple levels. Implantation of as few as 100 JoPaca-1 cells into immunodeficient mice gave rise to tumours that were histologically very similar to the primary tumour. The high heterogeneity of JoPaca-1 was reflected by diverse cell morphology and a substantial number of chromosomal aberrations. Comparative whole-genome sequencing of JoPaca-1 and BxPC-3 revealed mutations in genes frequently altered in pancreatic cancer. Exceptionally high expression of cancer stem cell markers and a high clonogenic potential in vitro and in vivo was observed. All of these attributes make this cell line an extremely valuable model to study the biology of and pharmaceutical effects on pancreatic cancer.
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