MiR-210 expression in tumor tissue and in vitro effects of its silencing in renal cell carcinoma

Renal cell carcinoma (RCC) is the most common neoplasm of adult kidney accounting for about 3 % of adult malignancies. MicroRNAs (miRNAs) are a class of naturally occurring, short non-coding RNAs that regulate gene expression at the post-transcriptional level. We determined global miRNA expression profiles of RCC and parallel renal parenchyma tissues by using quantitative reverse transcriptase-polymerase chain reaction-based TaqMan low-density arrays. Afterward, we validated the difference in miR-210 expression levels on the larger group of RCC patients (35 RCC versus 10 non-tumorous parenchyma samples). Functional in vitro experiments were performed on ACHN and CAKI-2 RCC cell lines transfected with miRNA-210 inhibitor. Cell viability, apoptosis, cell cycle, scratch wound migration assay, and invasion assay (xCELLigence) were performed. We have identified original ccRCC-specific miRNA signature in clinical samples (73 miRNAs were significantly downregulated and five miRNAs upregulated (P < 0.003)). Increased expression levels of miR-210 in RCC tumor tissue were independently validated. We observed decreased viability of ACHN and CAKI-2 cells and accumulation of CAKI-2 in G2 phase of cell cycle after silencing of miR-210 expression. Downregulation of miR-210 also reduced the migratory and invasive potential of ACHN metastatic RCC cells. Moreover, we showed downregulation of HIF1a protein in both cell lines after miR-210 silencing indicating participation of miR-210 in hypoxic processes of RCC not only through regulation of its target mRNAs but also by indirect regulation of HIF1a. To our knowledge, this is the first report to show miR-210 regulatory effects on cell migration, invasive potential, and HIF1a protein in RCC cells.

Akt expression and compartmentalization in prediction of clinical outcome in HER2-positive metastatic breast cancer patients treated with trastuzumab

Trastuzumab is effective in about half of HER2-positive breast cancer patients. The PI3K/Akt signalling pathway plays an important role in the process of primary and secondary resistance to anti-HER2 targeted therapy. We evaluated the relationship between expression, activation and subcellular localization of selected Akt isoforms and response to trastuzumab-based anti-HER2 targeted therapy in patients with HER2-positive metastatic breast cancer. Seventy-four women with verified HER2-positive breast cancer were treated with trastuzumab for metastatic disease. Immunohistochemistry was used to evaluate Akt1, Akt2, pAkt Thr308 and pAkt Ser473 expression. For pAkt, cytoplasmic and nuclear fractions were assessed separately. Even though Akt isoforms were expressed in the majority of tumours, activated Akt (pAkt) was present in the cytoplasm only and not in the nucleus in >20% of tumours, and there was no pAkt at all in another 7–13% of tumours. Patients whose tumours showed strong Akt2 expression and had pAkt (pAkt-Thr308 and/or pAkt-Ser473) detectable in the cytoplasm as well as nucleus (n+c), exhibited improved time to progression (TTP) and overall survival from the initiation of trastuzumab therapy (OSt). Patients with tumours with strong Akt2 and pAkt Thr308 (n+c) had superior TTP (17.0 vs. 7.6 months, P=0.024; HR 0.52) and OSt (51.8 vs. 16.8 months, P=0.0009; HR 0.34) compared to other tumours. Similar results were found for strong Akt2 and pAkt Ser473 (n+c): TTP 13.1 vs. 7.2 months (P=0.085, HR 0.62) and OSt 50.8 vs. 17.0 months (P=0.009; HR 0.45). This study is the first to prove the significance of Akt kinase isoform, activity and compartmentalization for the prediction of response to trastuzumab-based therapy in patients with HER2-positive metastatic breast cancer.

Common polymorphisms in GSTM1, GSTT1, GSTP1, GSTA1 and susceptibility to colorectal cancer in the Central European population

Background

Central Europe presents with the highest incidence of sporadic colorectal cancer (CRC) worldwide. As sporadic CRC represents a typical multifactorial disease, it is characterized by intense interaction of the genetic background with the environment. Glutathione S-transferases could act as attractive susceptibility genes for CRC, as they are directly involved in conjugation between glutathione and chemotherapeutics, environmental pollutants and a wide spectrum of xenobiotics.

Methods

In this study, we investigated associations of polymorphisms in glutathione S-transferases (GSTs) genes, that is GSTA1, GSTT1, GSTM1 and GSTP1, with CRC in a total of 197 cases and 218 controls originating from the Czech Central European population. Polymorphisms were assessed by polymerase chain reaction/restriction fragment length polymorphism-based methods, allele-specific multiplex and allelic discrimination by real-time polymerase chain reaction.

Results

None of investigated polymorphisms showed any associations with CRC, with the exception of GSTP1; where the heterozygote genotype Ile105Val was associated with decreased risk of CRC (P = 0.043).

Conclusions

The frequencies observed in our study are in accordance with those from other European Caucasian populations. Based on our studies, examined variability in GST genes is not a major determinant of CRC susceptibility in the Central European population.

Evaluation of SNPs in miR-196-a2, miR-27a and miR-146a as risk factors of colorectal cancer

AIM: To investigate whether selected single nucleotide polymorphisms (SNPs) in miR-196a2, miR-27a and miR-146a genes are associated with sporadic colorectal cancer (CRC).

METHODS: In order to investigate the effect of these SNPs in CRC, we performed a case-control study of 197 cases of sporadic CRC and 212 cancer-free controls originating from the Central-European Caucasian population using TaqMan Real-Time polymerase chain reaction and allelic discrimination analysis.

RESULTS: The genotype and allele frequencies of SNPs were compared between the cases and the controls. None of the performed analysis showed any statistically significant results.

CONCLUSION: Our data suggest a lack of association between rs11614913, rs895819 and rs2910164 and colorectal cancer risk in the Central-European Caucasian population, a population with an extremely high incidence of sporadic colorectal cancer.

Genetic polymorphisms and microRNAs: new direction in molecular epidemiology of solid cancer

MicroRNAs (miRNAs) are small non-coding RNAs, which regulate gene expression. Single nucleotide polymorphisms (SNPs) may occur in miRNA biogenesis pathway genes, primary miRNA, pre-miRNA or a mature miRNA sequence. Such polymorphisms may be functional with respect to biogenesis and actions of mature miRNA. Specific SNPs were identified in predicted miRNA target sites within 3′ untranslated regions of mRNAs. These SNPs have a potential to affect the efficiency of miRNA binding to the target sites or can create or disrupt binding sites. Resulting gene dysregulation may involve changes in phenotype and may eventually prove critical for the susceptibility to cancer and its onset as well as for estimates of prognosis and therapy response. In this review, we provide a comprehensive list of potentially functional miRNA-related SNPs and summarize their importance as candidate cancer biomarkers.

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

BACKGROUND

Renal 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.

METHODS

In 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.

RESULTS

We 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.

CONCLUSION

Considering 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 VIRTUAL: Slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/7383071387016614.

Novel classes of non-coding RNAs and cancer

For the many years, the central dogma of molecular biology has been that RNA functions mainly as an informational intermediate between a DNA sequence and its encoded protein. But one of the great surprises of modern biology was the discovery that protein-coding genes represent less than 2% of the total genome sequence, and subsequently the fact that at least 90% of the human genome is actively transcribed. Thus, the human transcriptome was found to be more complex than a collection of protein-coding genes and their splice variants. Although initially argued to be spurious transcriptional noise or accumulated evolutionary debris arising from the early assembly of genes and/or the insertion of mobile genetic elements, recent evidence suggests that the non-coding RNAs (ncRNAs) may play major biological roles in cellular development, physiology and pathologies. NcRNAs could be grouped into two major classes based on the transcript size; small ncRNAs and long ncRNAs. Each of these classes can be further divided, whereas novel subclasses are still being discovered and characterized. Although, in the last years, small ncRNAs called microRNAs were studied most frequently with more than ten thousand hits at PubMed database, recently, evidence has begun to accumulate describing the molecular mechanisms by which a wide range of novel RNA species function, providing insight into their functional roles in cellular biology and in human disease. In this review, we summarize newly discovered classes of ncRNAs, and highlight their functioning in cancer biology and potential usage as biomarkers or therapeutic targets.

Same or not the same? Comparison of adipose tissue-derived versus bone marrow-derived mesenchymal stem and stromal cells

Mesenchymal stem/stromal cells (MSCs) comprise a heterogeneous population of cells with multilineage differentiation potential, the ability to modulate oxidative stress, and secrete various cytokines and growth factors that can have immunomodulatory, angiogenic, anti-inflammatory and anti-apoptotic effects. Recent data indicate that these paracrine factors may play a key role in MSC-mediated effects in modulating various acute and chronic pathological conditions. MSCs are found in virtually all organs of the body. Bone marrow-derived MSCs (BM-MSCs) were discovered first, and the bone marrow was considered the main source of MSCs for clinical application. Subsequently, MSCs have been isolated from various other sources with the adipose tissue, serving as one of the alternatives to bone marrow. Adipose tissue-derived MSCs (ASCs) can be more easily isolated; this approach is safer, and also, considerably larger amounts of ASCs can be obtained compared with the bone marrow. ASCs and BM-MSCs share many biological characteristics; however, there are some differences in their immunophenotype, differentiation potential, transcriptome, proteome, and immunomodulatory activity. Some of these differences may represent specific features of BM-MSCs and ASCs, while others are suggestive of the inherent heterogeneity of both BM-MSC and ASC populations. Still other differences may simply be related to different isolation and culture protocols. Most importantly, despite the minor differences between these MSC populations, ASCs seem to be as effective as BM-MSCs in clinical application, and, in some cases, may be better suited than BM-MSCs. In this review, we will examine in detail the ontology, biology, preclinical, and clinical application of BM-MSCs versus ASCs.

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

Background

Breast 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.

Methods

Thirty-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.

Results

Expression 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.

Conclusions

MiR-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.

Circulating miR-378 and miR-451 in serum are potential biomarkers for renal cell carcinoma

Background

There is no standard serum biomarker used for diagnosis or early detection of recurrence for renal cell carcinoma (RCC) patients. MicroRNAs (miRNAs) are abundant and highly stable in blood serum, and have been recently described as powerful circulating biomarkers in a wide range of solid cancers. Our aim was to identify miRNA signature that can distinguish the blood serum of RCC patients and matched healthy controls and validate identified miRNAs as potential biomarkers for RCC.

Methods

In the screening phase of the study, blood serum of 15 RCC patients and 12 matched healthy controls were analyzed by use of the TaqMan Low-Density Arrays enabling parallel identification of expression levels of 667 miRNAs through qRT-PCR-based approach. In the validation phase, identified miRNAs were further evaluated on the independent group of 90 RCC patients and 35 matched healthy controls by use of individual qRT-PCR assays and statistically evaluated.

Results

We identified 30 miRNAs differentially expressed between serum of RCC patients and healthy controls: 19 miRNAs were up-regulated and 11 miRNAs were down-regulated in RCC patients. MiR-378, miR-451 and miR-150 were further evaluated in the independent group of patients, and two of them were successfully validated: levels of miR-378 were increased (p = 0.0003, AUC = 0.71), miR-451 levels were decreased (p < 0.0001, AUC = 0.77) in serum of RCC patients. Combination of miR-378 and miR-451 enable identification of RCC serum with the sensitivity of 81%, specificity 83% and AUC = 0.86.

Conclusions

Circulating miRNAs in serum are promising biomarkers in RCC.

Expression levels of transcribed ultraconserved regions uc.73 and uc.388 are altered in colorectal cancer

OBJECTIVES

The development of colorectal cancer (CRC) is characterized by multiple genetic alterations. Transcribed ultraconserved regions (T-UCRs) are a subset of 481 sequences longer than 200 bp, which are absolutely conserved between orthologous regions of human, rat and mouse genomes, and are actively transcribed. It has recently been proven in cancer systems that differentially expressed T-UCRs could alter the functional characteristics of malignant cells. Genome-wide profiling revealed that T-UCRs have distinct signatures in human leukemia and carcinoma.

METHODS

In our study, we examined the expression levels of uc.43, uc.73, uc.134, uc.230, uc.339, uc.388 and uc.399 in 54 samples of primary colorectal carcinomas and 15 samples of non-tumoral adjacent tissues by real-time PCR. T-UCR expression levels were also correlated with commonly used clinicopathological features of CRC.

RESULTS

Expression levels of uc.73 (p = 0.0139) and uc.388 (p = 0.0325) were significantly decreased in CRC tissue, and uc.73 indicated a positive correlation with overall survival (p = 0.0315). The lower expression of uc.388 was associated with the distal location of CRC (p = 0.0183), but no correlation of any evaluated T-UCR with clinical stage, grade and tumor diameter was observed.

CONCLUSION

Our preliminary results suggest that uc.73 and uc.388 could be potential diagnostic and prognostic biomarkers in CRC patients.

Multifunctional immune-modulatory protein HLA-E identified in classical Hodgkin lymphoma: possible implications

Although the role of the non-classical human leukocyte antigen E (HLA-E) was originally thought to be limited to the development of a maternal tolerance to a semiallogeneic fetal graft, it is now known that HLA-E exerts multiple immunoregulatory functions. The significance of the presence of HLA-E in neoplastic cells and/or background microenvironment cells in classical Hodgkin lymphoma (cHL) is not well characterized. In our study, we evaluated the presence of HLA-E in both neoplastic and background cells in 40 cases of cHL. We found HLA-E in both neoplastic and background cells. There was a positive statistical correlation between the expression of HLA-E in neoplastic cells and the clinical stage of the disease, which indicates an immune-tolerogenic property of this multiple-purpose molecule. The presence of HLA-E in background cells seems to be prognostically neutral but its significance still needs to be determined. The mechanisms regulating the immunopathology of cHL neoplastic cells with respect to the presence of these molecule deserve further studies.

MicroRNAs and glioblastoma: roles in core signalling pathways and potential clinical implications

MicroRNAs (miRNAs) are endogenously expressed small non-coding RNAs that act as post-transcriptional regulators of gene expression. Dysregulation of these molecules has been indicated in the development of many cancers. Altered expression levels of several miRNAs were identified also in glioblastoma. It was repeatedly found that miRNAs are involved in important signalling pathways, which play roles in crucial cellular processes, such as proliferation, apoptosis, cell cycle regulation, invasion, angiogenesis and stem cell behaviour. Therefore, miRNAs represent promising therapeutic targets in glioblastoma. In this review, we summarize the current knowledge about miRNAs significance in glioblastoma, with special focus on their involvement in core signalling pathways, their roles in drug resistance and potential clinical implications.

MiR-195, miR-196b, miR-181c, miR-21 expression levels and O-6-methylguanine-DNA methyltransferase methylation status are associated with clinical outcome in glioblastoma patients

Glioblastoma multiforme (GBM) is the most frequently occurring primary malignant brain tumor; patients with GBM often have a very poor prognosis and differing responses to treatment. Therefore, it is very important to find new biomarkers that can predict clinical outcomes and help in treatment decisions. MicroRNAs are small, non-coding RNAs that function as post-transcriptional regulators of gene expression and play a key role in the pathogenesis of GBM. In a group of 38 patients with primary GBM, we analyzed the expression of eight microRNAs (miR-21, miR-128a, miR-181c, miR-195, miR-196a, miR-196b, miR-221, and miR-222). In addition, we examined the methylation status of O-6-methylguanine-DNA methyltransferase (MGMT) promoter by high-resolution melting analysis, as this has been shown to be a predictive marker in GBM. MGMT methylation status correlated with progression-free survival (P = 0.0201; log-rank test) as well as with overall survival (P = 0.0054; log-rank test). MiR-195 (P = 0.0124; log-rank test) and miR-196b (P = 0.0492; log-rank test) positively correlated with overall survival. Evaluation of miR-181c in combination with miR-21 predicted time to progression within 6 months of diagnosis with 92% sensitivity and 81% specificity (P < 0.0001). Our data confirmed that the methylation status of MGMT but also miR-21, miR-181c, miR-195, and miR-196b to be associated with survival of GBM patients. Above all, we suggest that the combination of miR-181c and miR-21 could be a very sensitive and specific test to identify patients at high risk of early progression after surgery.

Expression of immune-modulatory molecules HLA-G and HLA-E by tumor cells in glioblastomas: an unexpected prognostic significance?

The role of nonclassical human leukocyte antigens G and E (HLA-G and HLA-E) was originally thought to be restricted to the protection of the fetus from a maternal allorecognition. Now it is known that HLA-G and HLA-E exert multiple immunoregulatory functions. A prognostic significance of the expression of HLA-G and HLA-E by neoplastic cells in glioblastoma is not well characterized. In this study, we evaluated the expression of HLA-G and HLA-E by neoplastic cells in 39 cases of glioblastoma. We found the production of HLA-G and HLA in a majority of cases. There was an unexpected positive correlation between the expression of HLA-E and length of survival. We speculate that the expression of this molecule by neoplastic cells may represent a coincidental selective pro-host advantage related to better response to subsequent therapeutic modalities. Mechanisms of glioblastoma cell pathophysiology and mechanisms of responses to therapeutic interventions in respect to the expression of these molecules deserves further study.

Gene expression of somatostatin receptor 4 predicts clinical outcome of patients with metastatic neuroendocrine tumors treated with somatostatin analogs

Somatostatin analogs (SSA) are the standard diagnostic and treatment tools in the clinical management of patients with neuroendocrine tumors (NETs) expressing somatostatin receptors (SSTRs). Although symptomatic and biochemical control is obtained with SSA in the majority of functional NETs, antineoplastic effects of SSA are partial and of limited duration. The aim of this study was to quantify expression levels of five SSTR subtypes (SSTR1-SSTR5) and correlate them with the clinical outcomes of patients with NETs who underwent SSA therapy. The expression levels were analyzed using real-time polymerase chain reaction in a series of 22 metastatic NETs with a median time of 10 months on the SSA therapy (range 2-82 months). The median duration of disease stabilization in patients who developed progression (n = 14) was 9 months (range 3-92 months). The median survival period for all patients was 44 months (range 3-175 months). According to RECIST criteria, one (5%) partial objective tumor response was obtained, disease stabilization was achieved in 10 (45%) patients, and progressive disease was observed in 11 (50%). Analysis of mRNA expression of the SSTR subtypes showed that SSTR2 and SSTR5 were expressed in all of the studied NETs; SSTR1 and SSTR4 in all but 3 tumors (86%); and SSTR3 in only 10 NETs (49%). Interestingly, our preliminary data suggest that only the levels of SSTR4, though it has the lowest affinity for SSA of all SSTR subtypes, were significantly associated with the stabilization of disease during SSA therapy (p = 0.0357). These levels correlated with time to progression (p = 0.0015) and overall survival (p = 0.0017) in NET patients.

MicroRNA-181 family predicts response to concomitant chemoradiotherapy with temozolomide in glioblastoma patients

MicroRNAs are endogenously expressed regulatory noncoding RNAs. Previous studies showed altered expression levels of several microRNAs in glioblastomas. In this study, we examined the expression levels of selected microRNAs in 22 primary glioblastomas and six specimens of adult brain tissue by real-time PCR method. In addition, we examined methylation status of MGMT promoter by methylation-specific real-time PCR, as this has been shown to be a predictive marker in glioblastomas. MGMT methylation status was not correlated with response to concomitant chemoradiotherapy with temozolomide (RT/TMZ). MiR-221 (p=0.016), miR-222 (p=0.038), miR-181b (p=0.036), miR-181c (p=0.043) and miR-128a (p=0.001) were significantly down-regulated in glioblastomas. The most significant change was observed for up-regulation in miR-21 expression in glioblastomas (p<0.001). MiR-181b and miR-181c were significantly down-regulated in patients who responded to RT/TMZ (p=0.016; p=0.047, respectively) in comparison to patients with progredient disease. Our data indicate for the first time that expression levels of miR-181b and miR-181c could serve as a predictive marker of response to RT/TMZ therapy in glioblastoma patients.

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

BACKGROUND

MicroRNAs are endogenously expressed regulatory noncoding RNAs. Previous studies have shown altered expression levels of several microRNAs in renal cell carcinoma.

METHODS

We 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.

RESULTS

The 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).

CONCLUSIONS

We 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.

Production of immune-modulatory nonclassical molecules HLA-G and HLA-E by tumor infiltrating ameboid microglia/macrophages in glioblastomas: a role in innate immunity?

The possible role of immune-modulatory nonclassical molecules HLA-G and HLA-E in an anti-tumoral response and development of glioblastoma is not well characterized. In this study, we evaluated an expression of HLA-G and HLA-E by activated tumor infiltrating microglia/macrophages. We found production of HLA-G and HLA-E by tumor infiltrating activated microglia/macrophages in a majority of glioblastomas. We speculate that the expression of these molecules by activated microglia/CNS macrophages plays a role in the anti-tumoral immunity in the development of glioblastoma. Mechanisms of microglia-glioblastoma cell interactions with respect to the expression of these molecules deserves further study.