Induction of Th1Immune responses following laser ablation in a murine model of colorectal liver metastases

<p>Abstract</p> <p>Background</p> <p>Preliminary experimental studies have suggested that the in situ destruction of tumor tissue by local laser ablation (LA) may also stimulate host immunity against cancer. We investigated local and systemic induction of immune responses after laser ablation in the setting of residual tumor.</p> <p>Methods</p> <p>A murine colorectal cancer (CRC) liver metastasis model was used. Selected tumors of liver CRC bearing mice and livers of mice without tumor induction were treated with LA. Liver and tumor tissues from the ablation sites and from distant sites were collected at various time points following LA and changes in CD3+ T cells and Kupffer cells (F4/80 marker) infiltration and the expression of interferon gamma (IFNγ) were investigated by immunohistochemistry and ELISpot. Base line levels of CD3+ T cells and Kupffer cells were established in untreated mice.</p> <p>Results</p> <p>The presence of tumor induced significant accumulation of CD3+ T cells and Kupffer cells at the tumor-host interface, within the tumor vascular lakes and increased their baseline concentration within the liver parenchyma. LA of the <it>liver </it>induced accumulation of CD3+ T-cells and Kupffer cells at the site of injury and systemic induction of immune responses as discerned by the presence of IFNγ secreting splenocytes. LA of liver <it>tumors </it>induced significant increase of CD3+ T-cells at site of injury, within normal liver parenchyma, and the tumor-host interface of both ablated and distant tumors. In contrast Kupffer cells only accumulated in ablated tumors and the liver parenchyma but not in distant tumors. IFNγ expression increased significantly in ablated tumors and showed an increasing trend in distant tumors.</p> <p>Conclusion</p> <p>Laser ablation in addition to local tumor destruction induces local and systemic Th1 type immune responses which may play a significant role in inhibiting tumor recurrence from residual micrometastases or circulating tumor cells.</p

The effect of hyperbaric oxygen on apoptosis and proliferation in severe acute pancreatitis

AbstractObjectivesThis paper investigates the significance of apoptosis in severe acute pancreatitis (SAP) and the possible modulating effects of hyperbaric oxygen (HBO).MethodsWistar rats (250–350g) were induced with SAP by biliopancreatic infusion of 4% sodium taurocholate. Rats were randomized for HBO treatment. Pancreatic tissue was stained for apoptosis with immunohistochemistry (anti-CASPASE-3 antibody and TUNEL), and histopathology haematoxylin and eosin (H&E). Acini were stained for proliferation with an anti-KI67 antibody. ImageProPlus was used to quantify apoptosis and proliferation in acinar cells. Statistical analysis was performed with two-independent-sample t-test or non-parametric Mann–Whitney test.ResultsIn normal acini there is a low rate of apoptosis (0.165 ± 0.157%, 0.181 ± 0.168%, 0.130 ± 0.298% in CASPASE-3, H&E and TUNEL, respectively) and proliferation (0.951 ± 0.926%) (mean ± standard deviation [SD]). When compared with normal, apoptosis (CASPASE-3: 1.28 ± 1.12%, P= 0.008; 2.40 ± 3.04%, P= 0.101; 1.23 ± 0.87%, P= 0.091; H&E: 0.47 ± 0.36%, P= 0.051; 0.69 ± 0.63%, P= 0.001; 0.68 ± 0.28%, P= 0; TUNEL: 1.08 ± 1.42%, P= 0; 1.96 ± 1.87%, P= 0; 2.36 ± 2.26%, P= 0) and proliferation (1.96 ± 1.89%, P= 0.187; 1.73 ± 1.76%, P= 0.165; 1.36 ± 1.40%, P= 0.571) were increased on days 1, 2 and 3 post-induction, respectively. In comparison with the untreated controls, HBO increased apoptosis on day 1 (CASPASE-3: 3.11 ± 1.97%, P= 0.04; H&E: 0.97 ± 0.76%, P= 0.005) and day 2 (TUNEL: 3.61 ± 3.05%, P= 0.034). Treatment with HBO increased proliferation (3.04 ± 3.14%, P= 0.519; 7.33 ± 7.55%, P= 0.153) on days 2 and 3, respectively, compared with the untreated controls.ConclusionsDuring SAP, acini apoptosis and proliferation were increased. Hyperbaric oxygen therapy may improve the condition of SAP by promoting apoptosis and proliferation

Treatment with the vascular disruptive agent OXi4503 induces an immediate and widespread epithelial to mesenchymal transition in the surviving tumor

Epithelial to mesenchymal transition (EMT) is considered an important mechanism in tumor resistance to drug treatments; however, in vivo observation of this process has been limited. In this study we demonstrated an immediate and widespread EMT involving all surviving tumor cells following treatment of a mouse model of colorectal liver metastases with the vascular disruptive agent OXi4503. EMT was characterized by significant downregulation of E-cadherin, relocation and nuclear accumulation of b-catenin as well as significant upregulation of ZEB1 and vimentin. Concomitantly, significant temporal upregulation in hypoxia and the pro-angiogenic growth factors hypoxia-inducible factor 1-alpha, hepatocyte growth factor, vascular endothelial growth factor and transforming growth factor-beta were seen within the surviving tumor. The process of EMT was transient and by 5 days after treatment tumor cell reversion to epithelial morphology was evident. This reversal, termed mesenchymal to epithelial transition (MET) is a process implicated in the development of new metastases but has not been observed in vivo histologically. Similar EMT changes were observed in response to other antitumor treatments including chemotherapy, thermal ablation, and antiangiogenic treatments in our mouse colorectal metastasis model and in a murine orthotopic breast cancer model after OXi4503 treatment. These results suggest that EMT may be an early mechanism adopted by tumors in response to injury and hypoxic stress, such that inhibition of EMT in combination with other therapies could play a significant role in future cancer therapy

Evaluating DNA recovery efficiency following bisulphite modification from plasma samples submitted for cell-free DNA methylation analysis

The detection of methylated templates in cell-free DNA (cfDNA) is increasingly recognized as a valuable, non-invasive tool for diagnosis, monitoring and prognostication in a range of medical contexts. The importance of controlling pre-analytical conditions in laboratory workflows prior to cfDNA quantification is well-established. Significant variations in the recovery of DNA following processes such as cfDNA extraction and sodium bisulphite modification may confound downstream analysis, particularly when accurate quantification of templates is required. Given the wealth of potential applications for this emerging molecular technology, attention has turned to the requirement to recognize and minimize pre-analytical variables prior to cfDNA methylation analysis. We recently described the development of an approach using an exogenous DNA construct to evaluate the recovery efficiency of cfDNA following the extraction and bisulphite modification steps (CEREBIS). Here, we report our experience in the practical application of this technique in 107 consecutive patient plasma samples submitted for quantitative cfDNA methylation analysis. The mean recovery of cfDNA (as estimated using cerebis), following extraction and bisulphite modification, was 37% ± 7%. Nine (8.4%) of the 107 samples were found to be outside of control limits, where the recovery of cerebis indicated significant differences in the efficiency of the pre-analytical processing of these samples. Recognition of these out-of-control samples precluded subsequent molecular analysis. Implementation of data-driven quality control measures, such as the one described, has the potential to improve the quality of liquid biopsy methylation analysis, interpretation and reporting

Changes in growth factor levels after thermal ablation in a murine model of colorectal liver metastases

AbstractObjectivesThis study examines changes in the expression of growth factors following thermal ablation (TA) of selected colorectal cancer (CRC) liver metastases.MethodsUsing mice with established CRC liver metastases, two tumours in each animal were thermally ablated. Liver and tumour tissues were collected at various time-points (days 0, 1, 2, 3, 5 and 7) following TA treatment from the ablation site and from sites distant from ablated tumour. Changes in growth factor expression (epidermal growth factor [EGF], vascular endothelial growth factor [VEGF], hepatocyte growth factor [HGF] and transforming growth factor-β[TGF-β]) in comparison with baseline levels (non-ablated) were assessed by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry.ResultsBaseline TGF-β and VEGF levels in the liver parenchyma of tumour-bearing mice were significantly higher than levels in naive liver parenchyma. Levels of VEGF and HGF decreased after TA treatment in all tissues. Levels of EGF decreased in ablated and distant tumour tissues, but displayed a tendency to increase in liver tissue. Levels of TGF-β also decreased during the first 2 days following TA, but later increased in liver and tumour tissues distant from the ablation site to a level that reached significance in tumour tissue at day 7 (P < 0.001). Decreases in growth factor levels were also observed in animals that underwent laparotomy without TA treatment, which indicates that these decreases were caused by the experimental procedure.ConclusionsTumour induces upregulation of TGF-β and VEGF in liver parenchyma. Growth factors decreased after TA, but this appears to be the result of the experimental procedure rather than the TA itself. However, TA resulted in increased levels of TGF-β, which may contribute to tumour recurrence