Ahmet Arslan

Differential Expression of a Set of Genes in Follicular and Classic Variants of Papillary Thyroid Carcinoma

Fine-needle aspiration biopsy (FNA) is currently the best initial diagnostic test for evaluation of a thyroid nodule. FNA cytology cannot discriminate between benign and malignant thyroid nodules in up to 30% of thyroid nodules. Therefore, an adjunct to FNA is needed to clarify these lesions as benign or malignant. Using differential display-polymerase chain reaction method, the gene expression differences between follicular and classic variants of papillary thyroid carcinoma (PTC) and benign thyroid nodules were evaluated in a group of 42 patients. Computational gene function analyses via Cytoscape, FuncBASE, and GeneMANIA led us to a functional network of 17 genes in which a core sub-network of five genes coexists. Although the exact mechanisms underlying in thyroid cancer biogenesis are not currently known, our data suggest that the pattern of transformation from healthy cells to cancer cells of PTC is different in follicular variant than in classic variant.

GJB2 and mitochondrial A1555G gene mutations in nonsyndromic profound hearing loss and carrier frequencies in healthy individuals

This study aimed to assess mutations in GJB2 gene (connexin 26), as well as A1555G mitochondrial mutation in both the patients with profound genetic nonsyndromic hearing loss and healthy controls. Ninety-five patients with profound hearing loss (>90 dB) and 67 healthy controls were included. All patients had genetic nonsyndromic hearing loss. Molecular analyses were performed for connexin 26 (35delG, M34T, L90P, R184P, delE120, 167delT, 235delC and IVS1+1 A → G) mutations, and for mitochondrial A1555G mutation. Twenty-two connexin 26 mutations were found in 14.7% of the patients, which were 35delG, R184P, del120E and IVS1+1 A → G. Mitochondrial A1555G mutation was not encountered. The most common GJB2 gene mutation was 35delG, which was followed by del120E, IVS1+1 A → G and R184P, and 14.3% of the patients segregated with DFNB1. In consanguineous marriages, the most common mutation was 35delG. The carrier frequency for 35delG mutation was 1.4% in the controls. 35delG and del120E populations, seems the most common connexin 26 mutations that cause genetic nonsyndromic hearing loss in this country. Nonsyndromic hearing loss mostly shows DFNB1 form of segregation.

The Adiponectin variants contribute to the genetic background of type 2 diabetes in Turkish population

Adiponectin, an adipose tissue specific protein encoded by the Adiponectin gene, modulates insulin sensitivity and plays an important role in regulating energy homeostasis. Many studies have shown that single nucleotide polymorphisms (SNPs) in the Adiponectin gene are associated with low plasma adiponectin levels, insulin resistance and an increased risk of type 2 diabetes mellitus. The aim of the present study was to evaluate the contribution of the Adiponectin gene polymorphisms in genetic background of type 2 diabetes in a Turkish population. In total, 169 unrelated and non-obese diabetic patients and 119 age- and BMI-matched non-diabetic individuals with no family history of diabetes were enrolled in this study. We detected a significant association between type 2 diabetes and two SNPs: SNP -11391G>A, which is located in the promoter region of the Adiponectin gene, and SNP +276G>T, which is found in intron 2 of the gene (P<0.05). The silence SNP G15G (+45T>G) in exon 1 and SNP +349A>G in intron 2 also showed a weak association with type 2 diabetes (P=0.06 and P=0.07, respectively), while SNPs -3971A>G in intron 1 and Y111H, R112C and H241P in exon 3 showed no association (P>0.05). In conclusion, these findings suggest that Adiponectin gene polymorphisms might be effective on susceptibility for type 2 diabetes development which emerged from the interactions between multiple genes, variants and environmental factors.

The association of the expression of miR-122-5p and its target ADAM10 with human breast cancer

MicroRNAs can regulate many biological functions. miR-122-5p has a tumor suppressor function through different molecular pathways. Also, our second hit, ADAM10, targeted by miR-122-5p, is a major determinant of HER2 shedding causing that trastuzumab cannot bind to HER2 receptors. Therefore, our analysis upon ADAM10 expression and miR-122-5p was a good point to understand molecular mechanism of breast cancer. In our study, we investigated the expression profiles of miR-122-5p and its target ADAM10 in 71 breast cancer patients. Immunohistochemical analysis of ER, PR and HER2 gene products was used to categorize tumors in patients. Expression data and immunohistochemical findings were evaluated to comment on the relationship between miR-122-5p and ADAM10. ADAM10 expression was higher in tumor than that of normal tissue but miR-122-5p expression was lower in tumor than that of normal tissue. The expression pattern in HER2+ patients was reverse of the overall result. It can be explained like that miR-122-5p expression increases especially in HER2+ cancer cell to suppress ADAM10 shedding activity on HER2 receptor. However, increase in expression of tumor suppressor miR-122-5p is not enough to inhibit ADAM10. All in all, we can think miR-122-5p as potential regulator of ADAM10 and trastuzumab resistance. Since if we increase miR-122-5p activity together with trastuzumab administration, then HER2+ breast cancer cells may overcome trastuzumab resistance by inhibiting ADAM10 shedding activity on HER2 receptors and increase the efficiency of trastuzumab.

Expression patterns of miR-221 and its target Caspase-3 in different cancer cell lines

Caspases are important initiators and most well-known finishers of apoptosis. By changing the death propagation homeostatic equilibrium, their different expression patterns might trigger the progression of hazardous diseases like cancer. miR-221 is an oncogenic miRNA. It is known to have both anti-angiogenic and angiogenic effect. The aim of this work was to compare the expression levels of miR-221 and its target caspase-3 in different cancer cell lines and to find out a relationship between these two. We also tried to establish a prominent relationship between miR-221 and its role in apoptosis by studying their expression levels. Our results indicate that expression of caspase-3 is quite lower as compared to miR-221 expression in all of the selected cancer cell lines. As a result, we conclude that miR-221 may have a crucial role in repressing the expression of caspase-3 which may contribute to a lower apoptotic rate, thus supporting the selection of more aggressive cancer cells. To our knowledge, this is the first study related to the expression levels of caspase-3 and miR-221 in different cell lines at the same time. We expect that our study might pave the way for better understanding the role of miR-221 in apoptotic regulation of caspase-3.

Percutaneous Sonographically Guided Treatment of Hydatid Cysts in Sheep Direct Injection of Mebendazole and Albendazole

Objective. The purpose of this study was to investigate the scolicidal effect of intracystic injection of benzimidazolic solutions in naturally infected sheep with hydatid disease. Methods. Twenty‐four sheep with 37 hydatid cysts were included in this study for percutaneous treatment with benzimidazolic solutions. The animals were divided into 3 groups: group I, treatment group with mebendazole; group II, treatment group with albendazole; and group III, control group with distilled water. All solutions were given percutaneously under sonographic guidance. Cyst contents were aspirated with a needle, and then scolicidal solutions were injected into the cysts; reaspiration was not done. Routine follow‐up sonographic images were taken on the 15th day after treatment, then once per month for 3 months, and then at 3‐month intervals thereafter. At the 1‐month follow‐up, the percutaneous aspirate yielded orange juice–like material containing necrotic debris without living scolices. Results. Sonography showed a reduction in cyst size in the benzimidazolic groups (groups I and II) and progressive changes in echo patterns. An anaphylactic reaction was observed during the procedure in 1 animal. After 12 months of sonographic follow‐up, the animals in all groups were killed, and macroscopic and microscopic changes in tissue samples were evaluated. At autopsy, no cysts with living scolices were found in the benzimidazolic groups, and the appearance of the treated cysts was different from that of those in the control group. Microscopic examination showed the degeneration, necrosis, and thickening of the cyst walls in the treatment groups. Conclusions. Intracystic injection of benzimidazolic solutions as scolicidal agents may be used for percutaneous treatment of hepatic hydatid cysts in sheep.

MicroRNA 603 acts as a tumor suppressor and inhibits triple-negative breast cancer tumorigenesis by targeting elongation factor 2 kinase

Triple negative breast cancer (TNBC) is an aggressive type of breast cancer characterized by the absence of defined molecular targets, including estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2) and is associated with high rates of relapse and distant metastasis despite surgery and adjuvant chemotherapy. The lack of effective targeted therapies for TNBC represents an unmet therapeutic challenge. Eukaryotic elongation factor 2 kinase (eEF2K) is an atypical calcium/calmodulin-dependent serine/threonine kinase that promotes TNBC tumorigenesis, progression, and drug resistance, representing a potential novel molecular target. However, the mechanisms regulating eEF2K expression are unknown. Here, we report that eEF2K protein expression is highly up-regulated in TNBC cells and patient tumors and it is associated with poor patient survival and clinical outcome. We found that loss/reduced expression of miR-603 leads to eEF2K overexpression in TNBC cell lines. Its expression results in inhibition of eEF2K by directly targeting the 3-UTR and the inhibition of tumor cell growth, migration and invasion in TNBC. In vivo therapeutic gene delivery of miR-603 into TNBC xenograft mouse models by systemic administration of miR-603-nanoparticles led to a significant inhibition of eEF2K expression and tumor growth, which was associated with decreased activity of the downstream targets of eEF2K, including Src, Akt, cyclin D1 and c-myc. Our findings suggest that miR-603 functions as a tumor suppressor and loss of miR-603 expression leads to increase in eEF2K expression and contributes to the growth, invasion, and progression of TNBC. Taken together, our data suggest that miR-603-based gene therapy is a potential strategy against TNBC.

Association Between the T-593A and C6982T Polymorphisms of the Osteopontin Gene and Risk of Developing Nephrolithiasis

BACKGROUND AND AIMSnIncreased synthesis of several urinary proteins including osteopontin (OPN) has been shown to be associated with stone formation within the urinary tract. The objective of this study was to analyze the genotype distributions and allele frequencies for OPN gene promoter T-593A and C6982T (in exon 7) polymorphisms among patients with kidney stones.nnnMETHODSnIn this case-control study, the study group consisted of 121 patients with radiologically confirmed nephrolithiasis. Genomic DNA from patients and control cases (n = 100) was analyzed by single-strand conformation polymorphism method and nucleotide sequence analysis.nnnRESULTSnHomozygous carriers of the T-593T genotype were more frequent, but carriers of the A-593A genotype were less frequent in patients than in controls. There was also an increase in -593T allele (88% in patients vs. 79% in controls) and decrease in -593A allele frequencies (21% in control vs. 12% in patients) in the nephrolithiasis groups (p = 0.013). The carriers of C6982C genotype were less frequent, but marked increases in T6982T genotype (25.6% in patients vs. 7% in controls, p = 0.001) and 6982T allele frequency (53.3% in patients vs. 37.5% in controls, p = 0.001) were noted in patients of Turkish ancestry.nnnCONCLUSIONSnThese results are the first to demonstrate the existence of T-593A promoter polymorphism of the OPN gene and significant association with risk of developing nephrolithiasis. Our results showed marked associations between polymorphisms (C6982T and T-593A) of the OPN gene and the stone-forming phenotypes in the Turkish population.

Screening of common and novel familial mediterranean fever mutations in south-east part of Turkey

Familial mediterranean fever (FMF) is an autosomal recessive autoinflammatory disorder (MIM# 249100), particularly common in populations of Mediterranean extraction. MEFV gene, responsible for FMF, encoding pyrin has recently been mapped to chromosome 16p13.3. In the present study, 3,341 unrelated patients with the suspicion of FMF in south-east part of Turkey between the years 2009 and 2013 were enrolled and genomic sequences of exon 2 and exon 10 of the MEFV gene were scanned for mutations by direct sequencing. We identified 43 different type of mutations and 9 of them were novel. DNA was amplified by PCR and subjected to direct sequencing for the detection of MEFV gene mutations. Among the 3,341 patients, 1,598 (47.8xa0%) were males and 1,743 (52.1xa0%) were females. The mutations were heterozygous in 806 (62.3xa0%), compound heterozygous in 188 (14.5xa0%), homozygous in 281 (21.8xa0%) and mutations had complex genotype in 17 (1.32xa0%) patients. No mutation was detected in 2,051 (61.4xa0%) patients. The most frequent mutations were M694V, E148Q, M680I(G/C) and V726A. We could not find any significant differences between the two common mutations according to the gender. Molecular diagnosis of MEFV is a useful tool in clinical practice, thus a future study relating to genotype/phenotype correlation of FMF in more and larger group in Turkish population involving the whole MEFV gene mutations is necessary.

The investigation of miR-221-3p and PAK1 gene expressions in breast cancer cell lines.

The most common malignancy in women is breast cancer. Drug resistance in the treatment of cancer still remains a major clinical concern. Resistance to tamoxifen is seen in half of the recurrences in breast cancer. The anti-estrogen tamoxifen gains agonistic property by transactivating ERα. PAK1-mediated phosphorylation of serine 305 (S305) of ERα leads to resistance to tamoxifen. In our study, PAK1-induced suggestive tamoxifen resistance was designed. According to our hypothesis, phosphorylation of ERα-S305 by PAK1 may be reversed by PAK1 transcriptional inhibition by miR-221-3p due to miR-221-3p targeting the 3 UTR of PAK1. For this purpose, we used Real-time PCR (qRT-PCR) to measure the expression level of miR-221-3p in ER-positive breast cancer cell lines (ZR-75-1, MCF7) and breast epithelial cell line, hTERT-HME1, as control in the laboratory in our department. The increase in the expression of PAK1 depending on miR-221-3p may be related to ZR-75-1 cell line which has invasive characteristic but other two ER+ cancer cell lines, MCF7 and HCC1500, have milder cancer severity. miR-221-3p may have a role on regulation of PAK1 expression because miR-221-3p expression level decreases while PAK1 expression level increases in SKBR3 cell line. miR-221-3p and PAK1 expressions in MDA-MB-231 cell line are higher than that of hTERT-HME1 cell line. This may mean that miR-221-3p has no regulatory effect on of PAK1 expression in this cell line. According to these results, miR-221-3p may give crucial information about molecular mechanism of the disease upon PAK1 activity or different mechanisms with respect to histopathology and severity of breast cancer.