Publications by authors named "Mirela Mihaila"

5 Publications

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Rare-Earth Metal Complexes of the Antibacterial Drug Oxolinic Acid: Synthesis, Characterization, DNA/Protein Binding and Cytotoxicity Studies.

Molecules 2020 Nov 19;25(22). Epub 2020 Nov 19.

Department of General and Inorganic Chemistry, Faculty of Pharmacy, Carol Davila University of Medicine and Pharmacy, 6 Traian Vuia St, 020956 Bucharest, Romania.

"Drug repositioning" is a current trend which proved useful in the search for new applications for existing, failed, no longer in use or abandoned drugs, particularly when addressing issues such as bacterial or cancer cells resistance to current therapeutic approaches. In this context, six new complexes of the first-generation quinolone oxolinic acid with rare-earth metal cations (Y, La, Sm, Eu, Gd, Tb) have been synthesized and characterized. The experimental data suggest that the quinolone acts as a bidentate ligand, binding to the metal ion via the keto and carboxylate oxygen atoms; these findings are supported by DFT (density functional theory) calculations for the Sm complex. The cytotoxic activity of the complexes, as well as the ligand, has been studied on MDA-MB 231 (human breast adenocarcinoma), LoVo (human colon adenocarcinoma) and HUVEC (normal human umbilical vein endothelial cells) cell lines. UV-Vis spectroscopy and competitive binding studies show that the complexes display binding affinities (K) towards double stranded DNA in the range of 9.33 × 10 - 10.72 × 10. Major and minor groove-binding most likely play a significant role in the interactions of the complexes with DNA. Moreover, the complexes bind human serum albumin more avidly than apo-transferrin.
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http://dx.doi.org/10.3390/molecules25225418DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7699381PMC
November 2020

Alterations of regulatory factors and DNA methylation pattern in thyroid cancer.

Cancer Biomark 2020 ;28(2):255-268

"CI Parhon" National Institute of Endocrinology, Bucharest, Romania.

Purpose: DNA methylation plays an important role in thyroid oncogenesis. The aim of this study was to investigate the connection between global and local DNA methylation status and to establish the levels of important DNA methylation regulators (TET family and DNMT1) in thyroid tumours: follicular adenoma-FA, papillary thyroid carcinoma-PTC (classic papillary thyroid carcinoma-cPTC and papillary thyroid carcinoma follicular variant fvPTC).

Methods: Global DNA methylation profile in thyroid tumours tissue (41 paired samples) was assessed by 5-methylcytosine and 5-hydroxymethylcytosine levels evaluation (ELISA), along with TETs and DNMT1 genes expression quantification. Also, it was investigated for the first time TET1 and TET2 promoter's methylation in thyroid tumours. BRAF V600E mutation and RET/PTC translocation testing were performed on all investigated samples. In vitro studies upon DNA methylation in K1 thyroid cancer cells were performed with demethylating agents (5-AzaC and vitamin C).

Results: TET1 and TET2 displayed a significantly reduced gene expression level in PTC, while DNMT1 gene presented a high level of expression. PTC samples presented increased levels of 5-methylcytosine and low levels of 5-hydroxymethylcytosine. 5-methylcytosine levels were associated with TET1/TET2 expression levels. TET1 gene expression was significantly lower in patients positive for BRAF mutation and with RET/PTC rearrangement. TET2 gene was found hypermethylated in thyroid carcinoma patients overall, especially in PTC-follicular variant samples (p= 0.0002), where TET2 gene expression levels were significantly reduced (p= 0.0031). Furthermore, the data indicate for all thyroid cancer patients a good sensitivity (81.08%) and specificity (86.49%) regarding the use of TET1 (p< 0.0001), and TET2 (71.79%, 64.10%, p= 0.0001) hypermethylation as biomarkers for thyroid oncogenesis.

Conclusions: These results suggest that TET1/TET2 gene expression and methylation may serve as potential diagnostic tools for thyroid neoplasia. Our study showed that the methylation of TET1 increases in malignant thyroid tumours. fvPTC patients presented lower methylation levels compared to cPTC and could be a discriminatory factor between two cancer types and benign lesions. TET2 is a poorer discriminator between FA and fvPTC, but it can be useful for cPTC identification. K1-cells treated with demethylating agents showed a demethylation effect, especially upon TET2 gene. The cumulative effect of L-AA and 5-AzaC proved to have a potent combined demethylating effect on genes promoter's activation and could open new perspectives for thyroid cancer therapy.
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http://dx.doi.org/10.3233/CBM-190871DOI Listing
January 2021

Cisplatin effect on head and neck squamous cell carcinoma cells is modulated by ERK1/2 protein kinases.

Exp Ther Med 2019 Dec 25;18(6):5041-5051. Epub 2019 Oct 25.

Department of Immunology, 'Victor Babeș' National Institute of Pathology, 050096 Bucharest, Romania.

The extracellular signal-regulated kinases (ERKs) are key transducers of the extracellular signals into intracellular responses and represent major molecular players in tumorigenesis. The aim of this study was to determine how curcumin (CRM) used as an adjuvant supports the apoptotic process induced by a single chemical agent treatment (cisplatin-CisPT) on two head and neck squamous cell carcinoma cell lines (FaDu and PE/CA-PJ49) and the involvement of ERK1/2 and/or p53 activation in this process. Data have shown that the CisPt effect is potentiated by CRM. CRM induced an increase of p53 protein phosphorylation in both cell lines. CisPt decreased p53 protein phosphorylation in FaDu cells, but increased it in PE/CA-PJ49 cells. Data showed that the constitutive expression of activated ERK1/2 protein-kinase was different in the two analyzed tumor cell lines. ERK1/2 activation status was essential for both cell processes, proliferation and apoptosis induced by CisPt and/or CRM treatment on squamous cell carcinoma cells. Our data suggest that p53 phosphorylation in the apoptotic process induced by CRM treatment might require the involvement of ERK1/2. In this regard the CisPt treatment suggested that p53 phosphorylation is ERK1/2 independent in FaDu cells having a p53 gene deletion and ERK1/2 dependent in PE/CA-PJ49 cells having a p53 gene amplification. Moreover, in both tumor cell lines our results support the involvement of p53 phosphorylation-ERK1/2 activation-dependent in the apoptosis induced by combined treatments (CisPt and CRM). The use of CRM as adjuvant could increase the efficiency of chemotherapy by modulating cellular activation processes of ERK1/2 signaling pathways. In conclusion, the particular mode of intervention by which ERK1/2 might influence cell proliferation and/or apoptosis processes depends on the type of therapeutic agent, the cells' particularities, and the activation status of the ERK1/2.
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http://dx.doi.org/10.3892/etm.2019.8139DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6880449PMC
December 2019

Methylation of tumour suppressor genes associated with thyroid cancer.

Cancer Biomark 2019 ;25(1):53-65

'CI Parhon' National Institute of Endocrinology, Bucharest, Romania.

Background: Thyroid carcinoma is the most common endocrine malignancy worldwide. Changes in DNA methylation can cause silencing of normally active genes, especially tumour suppressor genes (TSG) or activation of normally silent genes.

Objective: The aim of this study is to evaluate the degree of promoter methylation for a panel of markers for thyroid neoplasms and to establish their relationship with thyroid oncogenesis.

Methods: To generate a comprehensive DNA methylation signature of TSGs involved in thyroid neoplasia, we use Human TSG EpiTect Methyl II Signature PCR Array-Qiagen for 24 samples (follicular adenomas and papillary thyroid carcinomas) compared with normal thyroid tissue. We extended the evaluation for three TSGs (TP73, WIF1, PDLIM4) using qMS-PCR. Statistical analysis was performed with GraphPad Prism.

Results: We noted four important genes NEUROG1, ESR1, RUNX3, MLH1, which presented methylated promoter in tumour samples compared to normal. We found new characteristic of thyroid tumours: methylation of TP73, WIF1 and PDLIM4 TSGs, which can contribute to thyroid neoplasia. A significant correlation between BRAF V600E mutation and RET/PTC rearrangements with TIMP3 and CDH13, RARB methylation, respectively was observed.

Conclusions: TSGs promoter hypermethylation is a hallmark of cancer and a test that uses methylation quantification method is suitable for diagnosis and prognosis of thyroid cancer.
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http://dx.doi.org/10.3233/CBM-182265DOI Listing
November 2019

Resveratrol modulates apoptosis in 5-fluorouracyl treated colon cancer cell lines.

Roum Arch Microbiol Immunol 2013 Oct-Dec;72(4):255-64

Since cancer is a cellular disease, it is essential to identify the development stages and use the information in the prediction, prevention, early detection and design of drug targets. Colon cancer represents a malignancy with high incidence and mortality throughout the world, its etiology involving many genetic, immunological and biochemical factors. 5-fluorouracyl (5-FU) is one of the most effective anti-cancer agents used in the treatment of colorectal cancers, but tumor chemoresistance is a major limiting factor of its use. In order to choose the most effective chemotherapeutic doses of 5-FU, and thereby diminish the side-effects, we tried to modulate the anticancer properties of 5-FU by adding dietary natural compounds. The study focused on the role of natural compounds as resveratrol (RSV) in sensitization of LoVo human colon adenocarcinoma cell line to 5-FU action. Real-time cell analysis (RTCA) by xCELLigence System was used to continuously monitor the cytotoxic effects of drug treatments on LoVo cells. RTCA allowed us to choose the proper concentrations for further end-point assays, such as flow-cytometry techniques used for the evaluation of apoptotic events, progression through cell cycle phases or nuclear antigen expression of compound-treated LoVo cells. Data obtained showed additional effects of RSV to 5-FU treatments on the increase ofapoptotic events, and suggested alternative approaches to obtain a stronger antitumor response, and diminished side-effects when low concentrations of anti-cancer drugs are used. Modulation of the mechanisms of programmed cell death process seem to be of great importance for malignant transformation, and therefore for anti-cancer therapeutic approaches.
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July 2014