Novel Βeta (ß)-Thalassemia Mutation in Turkish Children.

Beta (ß)-thalassemia is the most frequently observed hereditary blood disorder in the world. It is characterized by deficiency of hemoglobin ß-globin gene and is also a profoundly heterogeneous both at the molecular and clinical level. In the case of ß-thalassemia, there is reduced (ß(+) type) or absent (ß(o) type) synthesis of the beta chains of hemoglobin. ß-Thalassemia clinically occurs in three main forms: major, intermedia and minor according to requirement of transfusion. The objective of this study was to evaluate ß-thalassemia mutations in 89 patients ranging from 2 months to 16 years of age, who enrolled to Medical School Research and Training Hospital, Gaziantep University. The direct DNA sequence analysis was performed for mutation scanning of ß-globin gene. 89 children with ß-Thalassemia including all types were analyzed, 16 different ß-thalassemia mutations were detected. We have also identified a novel mutation (HBB.c.-80delT, rs397509430) in the promoter region (-30 TATA box) of ß-globin gene, and clinical data of patient having novel mutation was given. The ß-Thalassemia mutations were determined as ß-Thalassemia major type in 42 patients (47.19 %), ß-Thalassemia intermedia in 4 (4.49 %), ß-Thalassemia minor in 43, (48.31 %) patients. The most frequent mutation was IVS I-110 G>A, followed by IVS I-1 G>A, IVS I-6 T>C, IVS II-1 G>A, respectively.

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.

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.