Kestutis Suziedelis

Promoter Hypermethylation in Tumour Suppressor Genes Shows Association with Stage, Grade and Invasiveness of Bladder Cancer

Aims: Superficial bladder cancer is a highly recurrent disease, with progression to muscle invasiveness occurring in 15–30% of cases. Promoter hypermethylation in a panel of tumour suppressor genes involved in cell cycle control, apoptosis and DNA repair was analyzed in superficial bladder tumours in order to evaluate the suitability of epigenetic biomarkers for an earlier prediction of the aggressive course of the disease. Method: Promoter hypermethylation in p16, RARβ, RASSF1A, DAPK, and MGMT genes was analyzed in 58 cases with superficial bladder cancer and 2 cases with benign urological disease using methylation-specific PCR. Results: Promoter hypermethylation was frequently detected in RARβ, RASSF1A and DAPK genes, and 62% of bladder tumours exhibited hypermethylation in at least one gene. The overall frequency of hypermethylation and the number of genes involved increased with tumour stage, grade and muscle invasiveness. Aberrant methylation of RASSF1A and RARβwas predominant (p < 0.05) in muscle-invasive tumours and high-grade tumours, respectively. Cases with concurrent hypermethylation in DAPK, p16 and RARβ genes were moresusceptible to relapse. Conclusion: The results suggest analysis of promoter hypermethylation as a valuable biomarker for prognosis of the aggressive course of disease in bladder cancer.

Erratum to: Optimal differentiation of high- and low-grade glioma and metastasis: a meta-analysis of perfusion, diffusion, and spectroscopy metrics.

Introduction To perform a meta-analysis of advanced magnetic resonance imaging (MRI) metrics, including relative cerebral blood volume (rCBV), normalized apparent diffusion coefficient (nADC), and spectroscopy ratios choline/creatine (Cho/Cr) and choline/N-acetyl aspartate (Cho/NAA), for the differentiation of high- and low-grade gliomas (HGG, LGG) and metastases (MTS).

Gene and miRNA expression profiles of mouse Lewis lung carcinoma LLC1 cells following single or fractionated dose irradiation

In clinical practice ionizing radiation (IR) is primarily applied to cancer treatment in the form of fractionated dose (FD) irradiation. Despite this fact, a substantially higher amount of current knowledge in the field of radiobiology comes from in vitro studies based on the cellular response to single dose (SD) irradiation. In addition, intrinsic and acquired resistance to IR remains an issue in clinical practice, leading to radiotherapy treatment failure. Numerous previous studies suggest that an improved understanding of the molecular processes involved in the radiation-induced DNA damage response to FD irradiation could improve the effectiveness of radiotherapy. Therefore, the present study examined the differential expression of genes and microRNA (miRNA) in murine Lewis lung cancer (LLC)1 cells exposed to SD or FD irradiation. The results of the present study indicated that the gene and miRNA expression profiles of LLC1 cells exposed to irradiation were dose delivery type-dependent. Data analysis also revealed that mRNAs may be regulated by miRNAs in a radiation-dependent manner, suggesting that these mRNAs and miRNAs are the potential targets in the cellular response to SD or FD irradiation. However, LLC1 tumors after FD irradiation exhibited no significant changes in the expression of selected genes and miRNAs observed in the irradiated cells in vitro, suggesting that experimental in vitro conditions, particularly the tumor microenvironment, should be considered in detail to promote the development of efficient radiotherapy approaches. Nevertheless, the present study highlights the primary signaling pathways involved in the response of murine cancer cells to irradiation. Data presented in the present study can be applied to improve the outcome and development of radiotherapy in preclinical animal model settings.

Changes of reduced glutathione and glutathione S-transferase levels in colorectal cancer patients undergoing treatment

Purpose: The available data concerning reduced glutathione (GSH) and glutathione S-transferase (GST) levels in colorectal cancer patients during the treatment process are contradictory and insufficient. Methods: Forty patients with metastatic colorectal cancer receiving FOLFOX4 chemotherapy with or without bevacizumab and 40 healthy volunteers were included in the study. Blood samples were taken before treatment, after 2 months and at the end of treatment in the patient group and once in the healthy volunteer group. The levels of GSH and GST in blood serum were evaluated by enzyme-linked immunosorbent assay (ELISA) according to the manufacturer’s instructions. Results: The serum level of GSH was significantly lower in colorectal cancer patients before treatment than in healthy volunteers (37.84 ± 19.39 μg/mL and 52.78 ± 19.39 μg/mL, respectively; p<0.001). After treatment, the level of GSH increased significantly, while the level of GST decreased significantly. These changes were observed only in the groups of patients with partial or complete response, having metastases only in the liver, receiving FOLFOX4 chemotherapy with bevacizumab, or undergoing resection or radiofrequency ablation of liver metastases. Conclusions: GSH and GST levels change significantly during the treatment process and these changes depend on the response to treatment, treatment type, and site of metastases. Further analysis of the changes in GSH and GST levels during treatment would allow the assessment of the predictive potential of this molecular marker.

Microenvironment dependent gene expression signatures in reprogrammed human colon normal and cancer cell lines

BackgroundSince the first evidence suggesting existence of stem-like cancer cells, the process of cells reprogramming to the stem cell state remains as an attractive tool for cancer stemness research. Current knowledge in the field of cancer stemness, indicates that the microenvironment is a fundamental regulator of cell behavior. With regard to this, we investigated the changes of genome wide gene expression in reprogrammed human colon normal epithelial CRL-1831 and colon carcinoma DLD1 cell lines grown under more physiologically relevant three-dimensional (3D) cell culture microenvironment compared to 2D monolayer.MethodsWhole genome gene expression changes were evaluated in both cell lines cultured under 3D conditions over a 2D monolayer by gene expression microarray analysis. To evaluate the biological significance of gene expression changes, we performed pathway enrichment analysis using the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. Gene network analysis was used to study relationships between differentially expressed genes (DEGs) in functional categories by the GeneMANIA Cytoscape toolkit.ResultsIn total, we identified 3228 and 2654 differentially expressed genes (DEGs) for colon normal and cancer reprogrammed cell lines, respectively. Furthermore, the expression of 1097 genes was commonly regulated in both cell lines. KEGG enrichment analysis revealed that in total 129 and 101 pathways for iPSC-CRL-1831 and for CSC-DLD1, respectively, were enriched. Next, we grouped these pathways into three functional categories: cancer transformation/metastasis, cell interaction, and stemness. β-catenin (CTNNB1) was confirmed as a hub gene of all three functional categories.ConclusionsOur present findings suggest common pathways between reprogrammed human colon normal epithelium (iPSC-CRL-1831) and adenocarcinoma (CSC-DLD1) cells grown under 3D microenvironment. In addition, we demonstrated that pathways important for cancer transformation and tumor metastatic activity are altered both in normal and cancer stem-like cells during the transfer from 2D to 3D culture conditions. Thus, we indicate the potential of cell culture models enriched in normal and cancer stem-like cells for the identification of new therapeutic targets in cancer treatment.

Microenvironment and Dose-Delivery-Dependent Response after Exposure to Ionizing Radiation in Human Colorectal Cancer Cell Lines

A significant body of knowledge about radiobiology is based on studies of single dose cellular irradiation, despite the fact that conventional clinical applications using dose fractionation. In addition, cellular radiation response strongly depends on cell–cell and cell–extracellular matrix (ECM) interactions, which are poorly established in cancer cells grown under standard 2D cell culture conditions. In this study, we investigated the response of human colorectal carcinoma (CRC) DLD1 and HT29 cell lines, bearing distinct p53 mutations, to a single 2 or 10 Gy dose or fractionated 5 × 2 Gy doses of radiation using global transcriptomics analysis. To examine cellular response to radiation in a cell–ECM-interaction-dependent manner, CRC cells were grown under laminin-rich ECM 3D cell culture conditions. Microarray data analysis revealed that, overall, a total of 1,573 and 935 genes were differentially expressed (fold change >1.5; P < 0.05) in DLD1 and HT29 cells, respectively, at 4 h postirradiation. However, compared to a single dose of radiation, fractionated doses resulted in significantly different transcriptomic response in both CRC cell lines. Furthermore, pathway enrichment analysis indicated that p53 pathway and cell cycle/DNA damage repair or immune response functional categories were most significantly altered in DLD1 or HT29 cells, respectively, after fractionated irradiations. Novel observations of radiation-response-mediated activation of pro-survival pathways in CRC cells grown under lr-ECM 3D cell culture conditions using fractionated doses provide new directions for the development of more efficient radiotherapy strategies. Our results also indicated that cell line specific radiation response with or without activation of the conventional p53 pathway is ECM dependent, suggesting that the ECM is a key component in cellular radiation response.