Open Access

Background and Aims: Gastrointestinal stromal tumors (GISTs) are rare malignancies but the most common mesenchymal tumors of the digestive tract. Recent advances in diagnostic imaging and an increasing incidence will confront us more frequently with stromal tumors. This single center study aimed to characterize GIST patients in terms of tumor location, clinical presentation, metastasis formation, as well as associated secondary malignancies. Methods: In a retrospective study, 104 patients with a histologically confirmed diagnosis of GIST, collected between 1993 and 2011, were characterized for several clinical features. Results: The most common GIST location was the stomach (67.6%) followed by the small intestine (16.2%). Gastrointestinal bleeding (55.8%) and abdominal pain (38.5%) were the most frequently reported symptoms whereas about one-third of patients remained clinically asymptomatic (31.6%); 14.4% of patients had either synchronous or metachronous metastases and there was a significant prevalence also in the low risk group. The proportion of secondary malignant associated neoplasms was 31% in our GIST cohort, among which gastrointestinal, genitourinary tumors, and breast cancer were the most prevalent. Conclusion: There was a considerable risk for metastasis formation and the development of secondary neoplasias that should encourage discussion about the appropriate surveillance strategy after surgery for GIST.

Objective: In the rat, the pancreatic islet transplantation model is an established method to induce hepatocellular carcinomas (HCC), due to insulin-mediated metabolic and molecular alterations like increased glycolysis and de novo lipogenesis and the oncogenic AKT/mTOR pathway including upregulation of the transcription factor Carbohydrate-response element-binding protein (ChREBP). ChREBP could therefore represent an essential oncogenic co-factor during hormonally induced hepatocarcinogenesis. Methods: Pancreatic islet transplantation was implemented in diabetic C57Bl/6J (wild type, WT) and ChREBP-knockout (KO) mice for 6 and 12 months. Liver tissue was examined using histology, immunohistochemistry, electron microscopy and Western blot analysis. Finally, we performed NGS-based transcriptome analysis between WT and KO liver tumor tissues. Results: Three hepatocellular carcinomas were detectable after 6 and 12 months in diabetic transplanted WT mice, but only one in a KO mouse after 12 months. Pre-neoplastic clear cell foci (CCF) were also present in liver acini downstream of the islets in WT and KO mice. In KO tumors, glycolysis, de novo lipogenesis and AKT/mTOR signalling were strongly downregulated compared to WT lesions. Extrafocal liver tissue of diabetic, transplanted KO mice revealed less glycogen storage and proliferative activity than WT mice. From transcriptome analysis, we identified a set of transcripts pertaining to metabolic, oncogenic and immunogenic pathways that are differentially expressed between tumors of WT and KO mice. Of 315 metabolism-associated genes, we observed 199 genes that displayed upregulation in the tumor of WT mice, whereas 116 transcripts showed their downregulated expression in KO mice tumor. Conclusions: The pancreatic islet transplantation model is a suitable method to study hormonally induced hepatocarcinogenesis also in mice, allowing combination with gene knockout models. Our data indicate that deletion of ChREBP delays insulin-induced hepatocarcinogenesis, suggesting a combined oncogenic and lipogenic function of ChREBP along AKT/mTOR-mediated proliferation of hepatocytes and induction of hepatocellular carcinoma.

Simple Summary Our electron microscopic (EM) findings indicate that hydrodynamic based plasmid transfer to the hepatocytes possibly occurs via active or passive endocytosis with the plasmid entrapment in membrane bound multiple vesicle and vacuoles. Our ultramorphological study on the vacuole containing mouse hepatocytes did not show disrupted plasma membrane or other signs of cellular damage, thus keeping out the mechanism like membrane poration, but cannot be entirely excluded at the micro level. Independent of the plasmid itself or its enclosed components, we have also found the vesicle formations is a non-specific process. Therefore, it remains to be clarified as how the active or passive mechanisms are involved, leading to the vesicle generation and DNA-entry to the nucleus of the hepatocytes. Abstract Hydrodynamic transfection (HT) or hydrodynamic tail vein injection (HTVi) is among the leading technique that is used to deliver plasmid genes mainly into the liver of live mice or rats. The DNA constructs are composed of coupled plasmids, while one contains the gene of interest that stably integrate into the hepatocyte genome with help of the other consisting sleeping beauty transposase system. The rapid injection of a large volume of DNA-solution through the tail vein induces an acute cardiac congestion that refluxed into the liver, mainly in acinus zone 3, also found through our EM study. Although, HT mediated hydrodynamic force can permeabilizes the fenestrated sinusoidal endothelium of liver, but the mechanism of plasmid incorporation into the hepatocytes remains unclear. Therefore, in the present study, we have hydrodynamically injected 2 mL volume of empty plasmid (transposon vector) or saline solution (control) into the tail vein of anesthetized C57BL/6J/129Sv mice. Liver tissue was resected at different time points from two animal group conditions, i.e., one time point per animal (1, 5, 10–20, 60 min or 24 and 48 hrs after HT) or multiple time points per animal (0, 1, 2, 5, 10, 20 min) and quickly fixed with buffered 4% osmium tetroxide. The tissues fed with only saline solution was also resected and fixed in the similar way. EM evaluation from the liver ultrathin sections reveals that swiftly after 1 min, the hepatocytes near to the central venule in the acinus zone 3 shows cytoplasmic membrane-bound vesicles. Such vesicles increased in both numbers and size to vacuoles and precisely often found in the proximity to the nucleus. Further, EM affirm these vacuoles are also optically empty and do not contain any electron dense material. Although, some of the other hepatocytes reveals sign of cell damage including swollen mitochondria, dilated endoplasmic reticulum, Golgi apparatus and disrupted plasma membrane, but most of the hepatocytes appeared normal. The ultrastructural findings in the mice injected with empty vector or saline injected control mice were similar. Therefore, we have interpreted the vacuole formation as nonspecific endocytosis without specific interactions at the plasma membrane.