Margit Resel

Differential survival trends of stage II colorectal cancer patients relate to promoter methylation status of PCDH10, SPARC, and UCHL1

Surgical excision of colorectal cancer at early clinical stages is highly effective, but 20–30% of patients relapse. Therefore, it is of clinical relevance to identify patients at high risk for recurrence, who would benefit from adjuvant chemotherapy. The objective of this study was to identify prognostic and/or predictive methylation markers in stage II colorectal cancer patients. Therefore, we selected six gene promoters (FZD9, PCDH10 (protocadherin 10), SFRP2, SPARC (secreted protein acidic and rich in cysteine), UCHL1 (ubiquitin carboxyl-terminal hydrolase 1), and WIF1) for methylation analysis in formalin-fixed, paraffin-embedded primary tumor samples of colorectal cancer patients (n=143) who were enrolled in a prospective randomized phase III trial of the Austrian Breast and Colorectal cancer Study Group. Patients were randomized to adjuvant chemotherapy with 5-fluorouracil and leucovorin or surveillance only. Survival analyses revealed that combined evaluation of three promoters (PCDH10, SPARC, and UCHL1) showed differential effects with regard to disease-free survival and overall survival in the two treatment groups (significance level 0.007). In the chemotherapy arm, a statistically insignificant trend for patients without methylation toward longer survival was observed (P=0.069 for disease-free survival and P=0.139 for overall survival). Contrary, patients in the surveillance arm without methylation in their gene promoters had shorter disease-free survival and overall survival (P=0.031 for disease-free survival and P=0.003 for overall survival), indicating a prognostic effect of methylation in this group (test for interaction, P=0.006 for disease-free survival and P=0.018 for overall survival). These results indicate that promoter methylation status of PCDH10, SPARC, and UCHL1 may be used both as prognostic and predictive molecular marker for colorectal cancer patients and, therefore, may facilitate treatment decisions for stage II colorectal cancer.

miR-196b-5p Regulates Colorectal Cancer Cell Migration and Metastases through Interaction with HOXB7 and GALNT5

Purpose: miR-196b-5p has been previously implicated in malignant transformation; however, its role in colorectal cancer has not been fully explored. In this study, we examine the clinical and biological relevance of miR-196b-5p, and the molecular pathways regulated by miR-196b-5p in colorectal cancer. Experimental Design: miR-196b-5p expression was quantitated by qRT-PCR in 2 independent cohorts composed of 292 patients with colorectal cancer in total, to explore its biomarker potential. Transient and stable gain- and loss-of-function experiments were conducted in a panel of colorectal cancer cell lines and mice, to evaluate the impact of miR-196b-5p on proliferation, chemosensitivity, migration/invasion, and metastases formation in vitro and in vivo. The molecular pathways influenced by miR-196b-5p were characterized using whole transcriptome profiling, in silico target prediction tools, luciferase interaction assays, and phenocopy/rescue gene knockdown experiments. Results: Low miR-196b-5p expression was significantly associated with metastases and poor outcomes in 2 independent colorectal cancer patient cohorts (P < 0.05, log-rank test). miR-196b-5p inhibition led to significantly increased colorectal cancer cell migration/invasion and metastases formation in mice, whereas ectopic overexpression showed the opposite phenotype. Molecular profiling and target confirmation identified an interaction between miR-196b-5p and HOXB7 and GALNT5, which in turn regulated colorectal cancer cell migration. Conclusions: The association of low levels of miR-196b-5p and poor prognosis in patients with colorectal cancer can be explained by its influence on cancer cell migration and metastases formation. miR-196b-5p has an impact on colorectal cancer progression pathways through direct interaction with genes involved in cancer cell migration. Clin Cancer Res; 23(17); 5255–66. ©2017 AACR.

Resistance to Apoptosis and Expansion of Regulatory T Cells in Relation to the Detection of Circulating Tumor Cells in Patients with Metastatic Epithelial Cancer

Regulatory T cells may be crucial in the development of T cell tolerance to malignancies and contribute to immune dysfunctions. We investigated the percentage, activity, and onset of apoptosis of T cell subpopulations by multicolor flow cytometry in metastatic epithelial cancer patients compared to normal controls. Furthermore, a possible relationship between the presence of circulating tumor cells detected by immunocytochemistry and immune cell abnormalities was evaluated. Our study demonstrated a significantly elevated proportion of regulatory T cells in cancer patients (p < 0.001). In contrast to all other T cell subpopulations, regulatory T cells showed comparable Annexin V-binding characteristics in patients and normal controls. No relationship between the detection of circulating tumor cells and immune dysfunction was observed. These results indicate that cancer patients have a higher number of regulatory T cells with resistance to apoptotic stimuli partly responsible for immune dysfunctions as often observed in cancer patients.

The predictive value of serum soluble E-cadherin levels in breast cancer patients undergoing preoperative systemic chemotherapy

OBJECTIVES To date, no reliable markers are available to predict response to or to assess prognosis after preoperative systemic chemotherapy (PST) in patients with locally advanced breast cancer. Previous studies demonstrated that elevated levels of soluble E-cadherin (sE-cadherin), a product of proteolytic cleavage of cell surface E-cadherin, are associated with higher risk for metastatic disease and poor prognosis in various tumor types. We, therefore, hypothesized that serum sE-cadherin levels measured before PST may correlate with pathological response. DESIGN AND METHODS In a retrospective analysis, sE-cadherin levels were measured in sera of 108 female patients with histologically proven breast cancer before initiation of PST by using a commercially available quantitative sandwich enzyme immunoassay technique. Patients received a median number of 4 (range 3-6) cycles of anthracyline-based chemotherapy. The median patient age was 51.5 (range 21-71) years. Tumor size was measured clinically and translated into the tumor-node-metastasis (TNM)-system before the start of chemotherapy. Histopathological response in surgically removed specimens was evaluated using a modified Sinn regression score. In univariate analyses the correlations between levels of sE-cadherin and pathological response to PST were calculated. RESULTS The histopathological regression scores correlated significantly with tumor grading (p=0.045), clinical lymph node status before PST (p=0.031) and sE-cadherin levels (p=0.039). No correlation was seen between histopathological regression scores and hormone receptor and menopausal status as well as Her2-neu status. CONCLUSION sE-cadherin may be a marker predicting response to PST for patients with breast cancer. Our findings warrant further evaluation of sE-cadherin in a prospective trial.

Comprehensive Analysis of miRNome Alterations in Response to Sorafenib Treatment in Colorectal Cancer Cells

MicroRNAs (miRNAs) are master regulators of drug resistance and have been previously proposed as potential biomarkers for the prediction of therapeutic response in colorectal cancer (CRC). Sorafenib, a multi-kinase inhibitor which has been approved for the treatment of liver, renal and thyroid cancer, is currently being studied as a monotherapy in selected molecular subtypes or in combination with other drugs in metastatic CRC. In this study, we explored sorafenib-induced cellular effects in Kirsten rat sarcoma viral oncogene homolog olog (KRAS) wild-type and KRAS-mutated CRC cell lines (Caco-2 and HRT-18), and finally profiled expression changes of specific miRNAs within the miRNome (>1000 human miRNAs) after exposure to sorafenib. Overall, sorafenib induced a time- and dose-dependent growth-inhibitory effect through S-phase cell cycle arrest in KRAS wild-type and KRAS-mutated CRC cells. In HRT-18 cells, two human miRNAs (hsa-miR-597 and hsa-miR-720) and two small RNAs (SNORD 13 and hsa-miR-3182) were identified as specifically sorafenib-induced. In Caco-2 cells, nine human miRNAs (hsa-miR-3142, hsa-miR-20a, hsa-miR-4301, hsa-miR-1290, hsa-miR-4286, hsa-miR-3182, hsa-miR-3142, hsa-miR-1246 and hsa-miR-720) were identified to be differentially regulated post sorafenib treatment. In conclusion, we confirmed sorafenib as a potential anti-neoplastic treatment strategy for CRC cells by demonstrating a growth-inhibitory and cell cycle–arresting effect of this drug. Changes in the miRNome indicate that some specific miRNAs might be relevant as indicators for sorafenib response, drug resistance and potential targets for combinatorial miRNA-based drug strategies.

MiR-371a-3p Serum Levels Are Increased in Recurrence of Testicular Germ Cell Tumor Patients

Metastatic testicular germ cell tumors (TGCTs) are a potentially curable disease by administration of risk-adapted cytotoxic chemotherapy. Nevertheless, a disease-relapse after curative chemotherapy needs more intensive salvage chemotherapy and significantly worsens the prognosis of TGCT patients. Circulating tumor markers (β-subunit of human chorionic gonadotropin (β-HCG), alpha-Fetoprotein (AFP), and Lactate Dehydrogenase (LDH)) are frequently used for monitoring disease recurrence in TGCT patients, though they lack diagnostic sensitivity and specificity. Increasing evidence suggests that serum levels of stem cell-associated microRNAs (miR-371a-3p and miR-302/367 cluster) are outperforming the traditional tumor markers in terms of sensitivity to detect newly diagnosed TGCT patients. The aim of this study was to investigate whether these miRNAs are also informative in detection of disease recurrence in TGCT patients after curative first line therapy. For this purpose, we measured the serum levels of miR-371a-3p and miR-367 in 52 samples of ten TGCT patients at different time points during disease relapse and during salvage chemotherapy. In our study, miR-371a-3p levels in serum samples with proven disease recurrence were 13.65 fold higher than levels from the same patients without evidence of disease (p = 0.014). In contrast, miR-367 levels were not different in these patient groups (p = 0.985). In conclusion, miR-371a-3p is a sensitive and potentially novel biomarker for detecting disease relapse in TGCT patients. This promising biomarker should be investigated in further large prospective trials.