Pavel Fabian

Altered Expression of miR-21, miR-31, miR-143 and miR-145 Is Related to Clinicopathologic Features of Colorectal Cancer

Objectives: Development and metastases of colorectal cancer (CRC) are characterized by multiple genetic alterations. MicroRNAs (miRNAs) are endogenously expressed regulatory noncoding RNAs. Previous, mainly preclinical studies showed altered expression levels of several miRNAs in CRC. Methods: In our study, the expression levels of miR-21, miR-31, miR-143 and miR-145 in 29 primary colorectal carcinomas and 6 non-tumor adjacent tissue specimens were examined by real-time polymerase chain reaction. miRNA expression levels were also correlated with commonly used clinicopath-ologic features of CRC. Results: Expression levels of analyzed miRNAs significantly differed among tumors and adjacent non-tumor tissues: miR-21 (p = 0.0001) and miR-31 (p = 0.0006) were upregulated, and miR-143 (p = 0.011) and miR-145 (p = 0.003) were downregulated in tumors. For the first time, a high expression of miR-21 was associated with lymph node positivity (p = 0.025) and the development of distant metastases (p = 0.009) in CRC patients. Thus, expression of miR-21 correlated with CRC clinical stage (p = 0.032). Furthermore, tumors >50 mm in maximal tumor diameter were characterized by lower expression of miR-143 (p = 0.006) and miR-145 (p = 0.003). We found no correlation between analyzed miRNAs and serum levels of carcinoembryonic antigen. Conclusion: Our results suggest possible roles of miR-21, miR-31, miR-143 and miR-145 in CRC.

Expression of miRNA-106b in conventional renal cell carcinoma is a potential marker for prediction of early metastasis after nephrectomy

BackgroundMicroRNAs are endogenously expressed regulatory noncoding RNAs. Previous studies have shown altered expression levels of several microRNAs in renal cell carcinoma.MethodsWe examined the expression levels of selected microRNAs in 38 samples of conventional renal cell carcinoma (RCC) and 10 samples of non-tumoral renal parenchyma using TaqMan real-time PCR method.ResultsThe expression levels of miRNA-155 (p < 0.0001), miRNA-210 (p < 0.0001), miRNA-106a (p < 0.0001) and miRNA-106b (p < 0.0001) were significantly over-expressed in tumor tissue, whereas the expression of miRNA-141 (p < 0.0001) and miRNA-200c (p < 0.0001) were significantly decreased in RCC samples. There were no significant differences between expression levels of miRNA-182 and miRNA-200b in tumor samples and renal parenchyma. Our data suggest that expression levels of miRNA-106b are significantly lower in tumors of patients who developed metastasis (p = 0.030) and miR-106b is a potential predictive marker of early metastasis after nephrectomy in RCC patients (long-rank p = 0.032).ConclusionsWe have confirmed previous observations obtained by miRNA microarray analysis using standardized real-time PCR method. For the first time, we have identified a prognostic significance of miRNA-106b, which, after validation on a larger group of patients, maybe useful as a promising biomarker in patients with RCC.

Identification and functional screening of microRNAs highly deregulated in colorectal cancer

MicroRNAs (miRNAs) constitute a robust regulatory network with post‐transcriptional regulatory efficiency for almost one half of human coding genes, including oncogenes and tumour suppressors. We determined the expression profile of 667 miRNAs in colorectal cancer (CRC) tissues and paired non‐tumoural tissues and identified 42 differentially expressed miRNAs. We chose miR‐215, miR‐375, miR‐378, miR‐422a and miR‐135b for further validation on an independent cohort of 125 clinically characterized CRC patients and for in vitro analyses. MiR‐215, miR‐375, miR‐378 and miR‐422a were significantly decreased, whereas miR‐135b was increased in CRC tumour tissues. Levels of miR‐215 and miR‐422a correlated with clinical stage. MiR‐135b was associated with higher pre‐operative serum levels of CEA and CA19‐9. In vitro analyses showed that ectopic expression of miR‐215 decreases viability and migration, increases apoptosis and promotes cell cycle arrest in DLD‐1 and HCT‐116 colon cancer cell lines. Similarly, overexpression of miR‐375 and inhibition of miR‐135b led to decreased viability. Finally, restoration of miR‐378, miR‐422a and miR‐375 inhibited G1/S transition. These findings indicate that miR‐378, miR‐375, miR‐422a and miR‐215 play an important role in CRC as tumour suppressors, whereas miR‐135b functions as an oncogene; both groups of miRNA contribute to CRC pathogenesis.

MicroRNA expression profile associated with response to neoadjuvant chemoradiotherapy in locally advanced rectal cancer patients.

BackgroundRectal cancer accounts for approximately one third of all colorectal cancers (CRC), which belong among leading causes of cancer deaths worldwide. Standard treatment for locally advanced rectal cancer (cT3/4 and/or cN+) includes neoadjuvant chemoradiotherapy with fluoropyrimidines (capecitabine or 5-fluorouracil) followed by radical surgical resection. Unfortunately, a significant proportion of tumors do not respond enough to the neoadjuvant treatment and these patients are at risk of relapse. MicroRNAs (miRNAs) are small non-coding RNAs playing significant roles in the pathogenesis of many cancers including rectal cancer. MiRNAs could present the new predictive biomarkers for rectal cancer patients.MethodsWe selected 20 patients who underwent neoadjuvant chemoradiotherapy for advanced rectal cancer and whose tumors were classified as most sensitive or resistant to the treatment. These two groups were compared using large-scale miRNA expression profiling.ResultsExpression levels of 8 miRNAs significantly differed between two groups. MiR-215, miR-190b and miR-29b-2* have been overexpressed in non-responders, and let-7e, miR-196b, miR-450a, miR-450b-5p and miR-99a* have shown higher expression levels in responders. Using these miRNAs 9 of 10 responders and 9 of 10 non-responders (p < 0.05) have been correctly classified.ConclusionsOur pilot study suggests that miRNAs are part of the mechanisms that are involved in response of rectal cancer to the chemoradiotherapy and that miRNAs may be promising predictive biomarkers for such patients. In most miRNAs we identified (miR-215, miR-99a*, miR-196b, miR-450b-5p and let-7e), the connection between their expression and radioresistance or chemoresistance to inhibitors of thymidylate synthetase was already established.

Predicting non-sentinel lymph node status after positive sentinel biopsy in breast cancer: What model performs the best in a Czech population?

Several models have previously been proposed to predict the probability of non-sentinel lymph node (NSLN) metastases after a positive sentinel lymph node (SLN) biopsy in breast cancer. The aim of this study was to assess the accuracy of two previously published nomograms (MSKCC, Stanford) and to develop an alternative model with the best predictive accuracy in a Czech population. In the basic population of 330 SLN-positive patients from the Czech Republic, the accuracy of the MSKCC and the Stanford nomograms was tested by the area under the receiver operating characteristics curve (AUC). A new model (MOU nomogram) was proposed according to the results of multivariate analysis of relevant clinicopathologic variables. The new model was validated in an independent test population from Hungary (383 patients). In the basic population, six of 27 patients with isolated tumor cells (ITC) in the SLN harbored additional NSLN metastases. The AUCs of the MSKCC and Stanford nomograms were 0.68 and 0.66, respectively; for the MOU nomogram it reached 0.76. In the test population, the AUC of the MOU nomogram was similar to that of the basic population (0.74). The presence of only ITC in SLN does not preclude further nodal involvement. Additional variables are beneficial when considering the probability of NSLN metastases. In the basic population, the previously published nomograms (MSKCC and Stanford) showed only limited accuracy. The developed MOU nomogram proved more suitable for the basic population, such as for another independent population from a mid-European country.

MiR-34b is associated with clinical outcome in triple-negative breast cancer patients

BackgroundBreast cancer is the most common malignancy with the highest incidence rates among women worldwide. Triple-negative breast cancer (TNBC) represents the major phenotype of basal-like molecular subtype of breast cancer, characterized by higher incidence in young women and a very poor prognosis. MicroRNAs (miRNAs) are small non-coding RNAs playing significant role in the pathogenesis of many cancers including breast cancer. Therefore, miRNAs are also potential prognostic and/or predictive biomarkers in triple-negative breast cancer patients.MethodsThirty-nine TNBC patients with available formalin-fixed paraffin-embedded (FFPE) tissues were enrolled in the study. MiR-34a, miR-34b, and miR-34c were analyzed using qRT-PCR and correlated to clinico-pathological features of TNBC patients.ResultsExpression levels of miR-34b significantly correlate with disease free survival (DFS) (p = 0.0020, log-rank test) and overall survival (OS) (p = 0.0008, log-rank test) of TNBC patients. No other significant associations between miR-34a, miR-34b, and miR-34c with available clinical pathological data were observed.ConclusionsMiR-34b expression negatively correlates with disease free survival and overall survival in TNBC patients. Thus, miR-34b may present a new promising prognostic biomarker in TNBC patients, but independent validations are necessary.

Serum-based microRNA signatures in early diagnosis and prognosis prediction of colon cancer

Early detection of colorectal cancer is the main prerequisite for successful treatment and reduction of mortality. Circulating microRNAs were previously identified as promising diagnostic, prognostic and predictive biomarkers. The purpose of this study was to identify serum microRNAs enabling early diagnosis and prognosis prediction of colon cancer. In total, serum samples from 427 colon cancer patients and 276 healthy donors were included in three-phase biomarker study. Large-scale microRNA expression profiling was performed using Illumina small RNA sequencing. Diagnostic and prognostic potential of identified microRNAs was validated on independent training and validation sets of samples using RT-qPCR. Fifty-four microRNAs were found to be significantly deregulated in serum of colon cancer patients compared to healthy donors (P < 0.01). A diagnostic four-microRNA signature consisting of miR-23a-3p, miR-27a-3p, miR-142-5p and miR-376c-3p was established (AUC = 0.917), distinguishing colon cancer patients from healthy donors with sensitivity of 89% and specificity of 81% (AUC = 0.922). This panel of microRNAs exhibited high diagnostic performance also when analyzed separately in colon cancer patients in early stages of the disease (T1-4N0M0; AUC = 0.877). Further, a prognostic panel based on the expression of miR-23a-3p and miR-376c-3p independent of TNM stage was established (HR 2.30; 95% CI 1.44-3.66; P < 0.0004). In summary, highly sensitive signatures of circulating microRNAs enabling non-invasive early detection and prognosis prediction of colon cancer were identified.

HLA-G and HLA-E specific mRNAs connote opposite prognostic significance in renal cell carcinoma

BackgroundRenal cell carcinoma (RCC) is characterized by its resistance to radiotherapy and/or chemotherapy. On the other hand, it is an immunogenic tumor - it is able to stimulate antitumor responses. A prognostic significance of HLA-G expression by neoplastic cells in RCC is not well characterized; significance HLA-E expression in RCC is not characterized at all.MethodsIn our study, we evaluated the expression of HLA-G and HLA-E specific mRNA transcripts produced by neoplastic cells in 38 cases of RCC and in 10 samples of normal kidney parenchyma. The results were statistically correlated with various clinico-pathological parameters.ResultsWe confirmed that HLA-G is downregulated in normal kidney tissue; if it is up-regulated in RCC, then it is connected to worse prognosis. On the other hand, HLA-E mRNA transcripts were present in both normal kidney tissue and RCC and their increasing concentrations counterintuitively carried better prognosis, more favorable pT stage and lower nuclear Fuhrmann’s grade.ConclusionConsidering the fact that there is known aberrant activation of HLA-G and HLA-E expression by interferons, identification of HLA-G and HLA-E status could contribute to better selection of RCC patients who could possibly benefit from more tailored neoadjuvant biological/immunological therapy. Thus, these molecules could represent useful prognostic biomarkers in RCC, and the expression of both these molecules in RCC deserves further study.The virtualSlide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/7383071387016614

AGR2 Predicts Tamoxifen Resistance in Postmenopausal Breast Cancer Patients

Endocrine resistance is a significant problem in breast cancer treatment. Thus identification and validation of novel resistance determinants is important to improve treatment efficacy and patient outcome. In our work, AGR2 expression was determined by qRT-PCR in Tru-Cut needle biopsies from tamoxifen-treated postmenopausal breast cancer patients. Our results showed inversed association of AGR2 mRNA levels with primary treatment response (P = 0.0011) and progression-free survival (P = 0.0366) in 61 ER-positive breast carcinomas. As shown by our experimental and clinical evaluations, elevated AGR2 expression predicts decreased efficacy of tamoxifen treatment. From this perspective, AGR2 is a potential predictive biomarker enabling selection of an optimal algorithm for adjuvant hormonal therapy in postmenopausal ER-positive breast cancer patients.

Identification of an AKT-dependent signalling pathway that mediates tamoxifen-dependent induction of the pro-metastatic protein anterior gradient-2.

The pro-metastatic protein anterior gradient-2 (AGR2) was previously demonstrated as a predictive factor of poor response to tamoxifen treatment. In this study we aimed to delineate the key signalling pathway that may contribute to regulation of AGR2 protein induction in order to identify novel targets to overcome tamoxifen resistance in tumour cells. Together, our data identify PDPK1-AKT as a pro-oncogenic signalling pathway that triggers AGR2 protein induction in response to tamoxifen and suggest that AKT inhibitors could be used as part of a therapeutic strategy to treat tamoxifen resistant, AGR2 over-expressing cancers.