Nina Petrovic

miR-21 Might be Involved in Breast Cancer Promotion and Invasion Rather than in Initial Events of Breast Cancer Development

Breast cancer (BC) is a heterogeneous disease that develops into a large number of varied phenotypes. One of the features used in its classification and therapy selection is invasiveness. MicroRNA-21 (miR-21) is considered to be an important element of BC invasiveness, and miR-21 levels are frequently increased in different tumor types compared with normal tissue, including the breast. Experimental and literature research has highlighted that miR-21 was always significantly elevated in every study that included invasive breast carcinomas compared with healthy breast tissue. The main goal of this research was to specify the predominant role of miR-21 in the different phases of BC pathogenesis, i.e. whether it was involved in the early (initiation), later (promotion), or late (propagation, progression) phases. Our second goal was to explain the roles of miR-21 targets in BC by an in silico approach and literature review, and to associate the importance of miR-21 with particular phases of BC pathogenesis through the action of its target genes. Analysis has shown that changes in miR-21 levels might be important for the later and/or late phases of breast cancerogenesis rather than for the initial early phases. Targets of miR-21 (TIMP3, PDCD4, PTEN, TPM1 and RECK) are also primarily involved in BC promotion and progression, especially invasion, angiogenesis and metastasis. miR-21 expression levels could perhaps be used in conjunction with the standard diagnostic parameters as an indicator of BC presence, and to indicate a phenotype likely to show early invasion/metastasis detection and poor prognosis.

miR-155 expression level changes might be associated with initial phases of breast cancer pathogenesis and lymph-node metastasis

BACKGROUND Breast carcinoma is heterogeneous disease. Understanding the process of invasion and metastasis and the selection of the therapy for patients with breast carcinomas still remains difficult. MicroRNAs are powerful gene expression regulators. Because of inconsistent findings, we have analyzed potential difference in miR-155 levels in three breast cancer groups. OBJECTIVES Our goals were to examine miR-155 expression levels in normal tissue, non-invasive and invasive breast carcinomas, and their association with standard clinical and pathological parameters and oncomiR-21, and to investigate the ability of miR-155 to separate invasive breast carcinomas with non-invasive component from pure invasive. METHODS In the group of 40 breast tissue samples, relative expression levels of miR-155 were examined with stem-loop quantitative real-time PCR using TaqMan technology. RESULTS The significant difference among four examined groups of the breast tissue was detected (p = 0.001). In the group of pure invasive tumors, patients with positive nodal status had significantly higher miR-155 levels (p = 0.046). CONCLUSION Our results suggest that miR-155 might be involved in breast cancer pathogenesis and in tumor spreading to the lymph nodes, and that it might be used as biomarker for additional stratification of patients with invasive breast carcinomas with non-invasive component.

Impairment of acetylcholine-mediated endothelium-dependent relaxation in isolated parotid artery of the alloxan-induced diabetic rabbit

The aim of this study was to assess the effect of type 1 diabetes mellitus (induced by a single intravenous injection of 100 mg kg(-1) of alloxan) on acetylcholine (ACh)-induced relaxation in isolated rabbit parotid gland feeding artery. Isometric force measurements and quantification of inducible nitric oxide synthase (iNOS) mRNA by real-time RT-PCR were made in parotid artery rings from diabetic and control rabbits. Acetylcholine induced concentration- and endothelium-dependent vasorelaxation that was significantly decreased in parotid artery rings from diabetic rabbits. Schild analysis of the ACh vasorelaxant effect, in the presence of selective muscarinic receptor antagonists, revealed involvement of the M(3) receptor subtype in parotid artery rings from both control and diabetic rabbits, with no change in antagonist affinity constants. The inhibitory effects of indomethacin, a non-selective inhibitor of cyclooxygenase, and of high potassium, an inhibitor of hyperpolarization, on ACh vasorelaxation were increased. The effect of N(G) -nitro-l-arginine, a non-selective inhibitor of NOS, was decreased in diabetes. S-methylisothiourea, a selective inhibitor of iNOS, significantly reduced ACh vasorelaxation only in parotid artery rings from diabetic rabbits. Also, up-regulation of iNOS mRNA expression was detected in parotid artery rings from diabetic rabbits. These results suggest that in parotid artery rings from diabetic rabbits, impaired endothelium-dependent vasorelaxation to ACh appears to be caused by the loss of a nitric oxide-mediated component and increased iNOS expression, and is unlikely to be caused by a change at the M(3) receptor level.

Levels of MicroRNA Heterogeneity in Cancer Biology

MicroRNAs (miRNAs) are post-transcriptional regulators of gene expression, involved in the silencing of messenger RNA (mRNA) translation. The importance of miRNA signatures in disease screening, prognosis, and progression of different tumor types and subtypes is increasing. miRNA expression levels change depending on numerous factors. In this review, we are describing the circumstances under which miRNA levels can change, these are named ‘levels’ of heterogeneity of miRNAs. miRNAs can have oncogenic, tumor suppressive, or both roles depending on tumor type and target mRNA whose translation they silence. The expression levels of a single miRNA may vary across different cancer types and subtypes, indicating that a miRNA signature may be tissue specific. miRNA levels of expression also vary during disease formation and propagation, indicating the presence of a time profile for their expression. The complexity of the miRNA-mRNA interference network mirrors different genetic and epigenetic changes that influence miRNA and mRNA availability to each other, and hence, their binding ability. The potential role of miRNAs as biomarkers is two-fold; first, for monitoring of the phases of cancer pathogenesis, and second, to characterize the particular type/subtype of cancer. It is important that a particular miRNA should be characterized by examining as many types and subtypes of cancers as are available, as well as being extracted from different types of samples, in order to obtain a complete picture of its behavior and importance in the disease pathology.

MicroRNA in breast cancer: The association with BRCA1/2

Breast cancer (BC) is a heterogeneous disease in an urgent need for developing novel research, classification, and therapy approaches. Breast cancer 1 (BRCA1) and breast cancer 2 (BRCA2) proteins are well described tumor suppressors with great potential to be the subjects of different therapies. MicroRNAs (miRNAs) are genetic elements that might be used to solve the complex BC puzzle. BRCA1 was described to be the target of up to 100 miRNAs. BRCA1 may directly repress miR-155 activity. In addition, miR-15/107/182-mediated downregulation of BRCA1 interrupt DNA repair and may change the course of BC therapy. miR-146a and miR-146-5p silencing BRCA1 may trigger formation of triple-negative and basal-like sporadic BC cases. miR-182 might effect the therapy outcome. miR-21 targeted therapy might be useful for the treatment of BRCA2 mutation carriers. miR-342 overexpression and the absence of functional BRCA1 gene might cause synthetic lethality, which might be used as a base for future therapies. The present review discusses the latest data from studies that focus on the complex network of miRNAs and BRCA1/2 related BCs, which might be important for improving the therapy within the patients with triple-negative BC (TNBC) and basal-like BC, and for understanding the formation of TNBC.

Low VHL mRNA Expression is Associated with More Aggressive Tumor Features of Papillary Thyroid Carcinoma

Alterations of the von Hippel–Lindau (VHL) tumor suppressor gene can cause different hereditary tumors associated with VHL syndrome, but the potential role of the VHL gene in papillary thyroid carcinoma (PTC) has not been characterized. This study set out to investigate the relationship of VHL expression level with clinicopathological features of PTC in an ethnically and geographically homogenous group of 264 patients from Serbia, for the first time. Multivariate logistic regression analysis showed a strong correlation between low level of VHL expression and advanced clinical stage (OR = 5.78, 95% CI 3.17–10.53, P<0.0001), classical papillary morphology of the tumor (OR = 2.92, 95% CI 1.33–6.44, P = 0.008) and multifocality (OR = 1.96, 95% CI 1.06–3.62, P = 0.031). In disease-free survival analysis, low VHL expression had marginal significance (P = 0.0502 by the log-rank test) but did not appear to be an independent predictor of the risk for chance of faster recurrence in a proportion hazards model. No somatic mutations or evidence of VHL downregulation via promoter hypermethylation in PTC were found. The results indicate that the decrease of VHL expression associates with tumor progression but the mechanism of downregulation remains to be elucidated.

miRNAs as Potential Treatment Targets and Treatment Options in Cancer

Standard cancer therapies for solid malignancies, such as chemotherapy and radiotherapy, are not target specific against cancer cells and are often not fully efficacious. Chemotherapy and radiotherapy may cause side effects, and the need to develop additional strategies for cancer treatment is urgent. MicroRNAs (miRNAs) are small non-coding RNAs with heterogeneous functions and have been described in almost every known cancer model. Besides their basic tumor-suppressive and oncogenic functions, they also have the potential to modulate chemotherapy and radiotherapy and to be manipulated with chemical compounds to make them chemically suitable for efficient delivery to cancer cells. It has been suggested that the level of expression of specific miRNAs could increase treatment efficacy by determining the stage of chemotherapy/radiotherapy sensitivity. Application of miRNAs alone or in combination with standard therapeutic strategies may significantly improve the success of cancer treatments in the future.

A quality of life assessment and the correlation between generic and disease-specific questionnaires scores in outpatients with chronic liver disease-pilot study

Abstract Introduction. Chronic liver diseases (CLD) are an important cause of morbidity and mortality in general population. The aim of this study was to analyze potential differences between patients with CLD and healthy control group, and to estimate the severity of CLD by using simple questionnaires: general health questionnaire (GHQ-12) and chronic liver disease questionnaire (CLDQ). Methods. A cross-sectional pilot study was performed in Zemun Clinical Hospital during years 2014 and 2015. Sixty participants were divided into 4 groups (15 per group): chronic alcoholic hepatitis, other chronic hepatitis, liver cirrhosis, and healthy control group. Entire study population chose one of four offered answers of structured questionnaires GHQ-12 and CLDQ, based on which mean model of end-stage liver disease (MELD) and Child-Turcotte-Pugh (CTP) scores were calculated. Results. Mean GHQ12 and CLDQ scores were 10.5 and 5.21 ± 1.11 respectively. Regarding certain CLDQ domain scores, a significant difference between alcoholic and non-alcoholic hepatitis groups in the worry domain was observed. Mean MELD score was 7.42 ± 2.89 and did not differ between chronic hepatitis groups, while mean CTP score was 5.73 ± 0.88. A statistically significant correlation was observed between GHQ12 and CLDQ scores (ρ = -0.404, p < 0.01), but not between subjective and objective scores. Conclusions. Mean GHQ12 and CLDQ scores pointed out to general psychological no-distress condition of the studied participants, as well as scarcely expressed CLD-specific complaints. Mean MELD and CTP scores indicated stable chronic liver diseases, with low three-month mortality rates in the cases of chronic hepatitis, as well as determination to Child A group in the case of liver cirrhosis.

TIMP-3 mRNA expression levels positively correlates with levels of miR-21 in in situ BC and negatively in PR positive invasive BC

BACKGROUND Breast carcinomas (BC) belong to a heterogeneous group of malignant diseases. Correct categorization of BC based on molecular biomarkers has a very important role in deciding the proper course of therapy for each patient. It has been already shown that the decrease of TIMP metalloproteinase inhibitor 3 (TIMP-3) together with overexpression of microRNA-21 (miR-21) might be involved in the process of BC invasion. This is the first study that examined relationship among miR-21, TIMP-3 mRNA and TIPM-3 protein levels in BC groups formed according to invasiveness. METHODS In this study, we used 46 breast cancer samples. Estrogen and progesterone receptor (ER, PR) protein levels were evaluated by immunohistochemistry (IHC) method. TIMP-3 mRNA expression was examined by two-step real-time quantitative PCR (qRT-PCR). Western blot analysis was performed for 16 samples. RESULTS Statistically significant differences in TIMP-3 expression levels between invasive groups were discovered in ER positive (ER+) (p=0.015), Her-2 negative (p=0.026) subgroups, and patients without lymph-node metastasis (p=0.039). Interestingly, significant positive correlation was detected between miR-21 and TIMP-3 mRNA levels (P<0.001, ρ=0.949) in the group of in situ tumors. TIMP-3 mRNA expression levels highly negatively correlated with levels of miR-21 in PR+ invasive BCs (p=0.007, ρ=-0.641). TIMP-3 protein levels negatively correlated with miR-21 levels in pure invasive BCs. CONCLUSION These data suggest that signaling pathways involved in formation and progression of BCs in groups formed according to invasiveness might be different. Our findings propose that TIMP-3 mRNA expression levels could be significant prognostic parameter, but within specific BC subtypes.

Effect of neuropeptide Y on norepinephrine-induced constriction in the rabbit facial artery after carotid artery occlusion.

BACKGROUND/AIM Atherosclerotic-occlusive changes could be observed in orofacial branches of the external carotid artery. Atherosclerosis-induced ischemia caused alteration in production and release of endothelial factors. The aim of this study was to investigate the influence of carotid artery occlusion (10, 30 and 60 min) on vascular effects of norepinephrine (NOR) and neuropeptide Y (NPY) in the isolated glandular branch of the rabbit facial artery, the main feeding artery for the submandibular gland. METHOD Changes in isometric tension were recorded in organ bath studies with arterial rings, before and after carotid artery occlusion. RESULTS Concentration-dependent vasocontractile effect of NOR was significantly augmented after 30 and 60 min of carotid occlusion, but only in the rings with intact endothelium. Given alone, NPY showed no effect in isolated glandular branch of the rabbit facial artery, but enhanced NOR vasoconstriction in all the investigated rings. NOR vasocontractile effect enhancement in the presence of NPY was attenuated after 30 and 60 min of carotid occlusion. Also, enhancement of NOR vasoconstriction by NPY was significantly higher in endothelium-intact rings compared to endothelium-denuded rings obtained after 30 and 60 min of carotid occlusion. CONCLUSION The present investigation provides results of increased vasocontractile effect of NOR and decreased enhancing effect of NPY on NOR vasoconstriction in the rabbit facial artery after carotid occlusion that is related to altered endothelium function.