Alterations in the Expression Level of mir-1246 and mir-224 in Breast Cancer Cell Lines After Treatment with Taxol Chemotherapeutic Agent

Background & objectives: Breast cancer is one of the most important cancers in women worldwide. Taxol as a chemotherapeutic agent, is used for treatment of breast cancer.The aim of this study was to investigate alterations in the expression of mir-1246 and mir-224 in four breast cancer cell lines after Taxol treatment with the goal of introducing them as a biochemical marker for determining response or resistance of breast cancer to the Taxol therapy. Methods: In this in vitro study, four breast cancer cell lines including MCF-7, MDA-MB-231, SKBR-3 and BT-474 were cultured in RPMI1640 medium supplemented with 10% FBS and antibiotics. Then, MTT assay was performed to determine IC50 concentration of Taxol. Cells were treated for 24 hours and then RNA extraction and cDNA synthesis were performed. Alterations in the expression level of mir-1246 and mir-224 were quantitated using qRT- PCR. Results: After treatment with Taxol, the expression level of mir-1246 was significantly up-regulated in two HER2-overexpressing cell lines, BT-474 (113 fold) and SKBR-3 (1.4 fold), and down-regulated in two HER2-negative cell lines, MCF-7 (45.5 fold) and MDA-MB-231 (7.7 fold). Expression of mir-224 was detected only in two cell lines including SKBR-3 and MDA-MB-231, and was down-regulated after treatment with Taxol (2.1 and 17.2 fold, respectively). Conclusions: According to the different pattern of alteration in the expression level of mir-1246 in HER2-overexpressing breast cancer cell lines compared to HER2-negative cell lines after treatment with Taxol, this miRNA could be a useful biomarker for responsiveness to Taxol in  different types of HER2-positive and -negative breast cancers

Evaluation of Prevalence and Quality of Root Resorption of Second Molar Adjacent the Impacted Third Molar in Cone-Beam Computed Tomograph

Impacted third molar reduces the bone level in the distal aspect of second molar, and sometimes it can lead to external root resorption of the adjacent second molar. The aim of this study was to evaluate the prevalence and quality of this resorption using cone-beam computed tomography scanning.Materials & Methods:In this descriptive study, CBCT images selected from 60 patients (including 107 maxillary & mandibular impacted third molars) were obtained from patients referring tomaxillofacial radiology department of dental faculty of Islamic Azad University of Isfahan (Khorasgan) in 2016. Under observation of oral radiologist, the images were examined (two times with one-week interval) in axial, coronal, and sagittal sections and recorded to diagnose external root resorption in CBCT. The data were analyzed via descriptive statistics including contingency tables and relative abundance.Results:The prevalence of external root resorption of second molar, adjacent to the third molar were43.25%. The most common type of third molar impaction were mesioangular third molars (41.1%) and in the next level were the vertical (28.1%), and distoangular (18.7) and then horizontal (12.1). The most common location of resorption in mandibular second molar teeth was in 1/3 of cervical (62.5%), and then 1/3 of apical (20.8%) and 1/3 of the middle (12.5%). Also one of teeth resorptions (4.2%) was between the 1/3 of apical and 1/3 of the middle. The most common site of resorption in maxillary second molar teeth was at 1/3 of the apical (68.45%), and then at the 1/3 of the middle (17.35%) and 1/3 of cervical (8.7%). With regards to the severity of resorption; 78.96% of resorptions were mild, 12.03% severe, and 9.03 were moderate.Conclusion:The prevalence of this type of resorption is almost high and the most common position of impacted third molars that resulted in this type of resorption are mesioangular and horizontal. Most common site of resorption in the maxilla was 1.3 of the apical and in the mandible was 1.3 of the cervical, which were often mild in resorption