Differential Expression of MicroRNA (MiR-27, MiR-145) among Dental Pulp Stem Cells (DPSCs) Following Neurogenic Differentiation Stimuli

Assessment of Endocyn on Dental Pulp Stem Cells (DPSCs): A Pilot Study of Endodontic Irrigant Effects

Many endodontic procedures within the pediatric population are performed with patients aged 12 years and older, using intracanal irrigants to complement mechanical debridement for the removal of debris and to disinfect the root canal system. The use of antimicrobial irrigants that limit damage to the dental pulp are the goals of endodontic biomaterials research. Using an existing biorepository of dental pulp stem cells (DPSCs), Endocyn was evaluated in varying concentrations in proliferation and viability assays, and compared with positive (sodium hypochlorite or bleach) and negative (phosphate-buffered saline) controls. The DPSC viability was reduced in the range of -8.3% to -15.8%, p = 0.22 to p = 0.042, while the growth inhibition varied between -29.7% and -63%, p = 0.041 to p = 0.022. However, the RNA analysis revealed that no significant changes in biomarker mRNA expression (Nestin, NANOG, Sox2, Oct4, CD73, CD90, and CD105) were observed. These data demonstrated that all of the concentrations of Endocyn inhibited the DPSC viability and growth, although only high concentrations were statistically significant. Moreover, the administration of Endocyn did not alter the DPSC biomarker expression, which are novel and important findings not previously observed or reported that may assist with the development of clinical decision protocols and methods for the treatment of vital pulp tissue.

Differential Expression of MicroRNA MiR-145 and MiR-155 Downstream Targets in Oral Cancers Exhibiting Limited Chemotherapy Resistance

New evidence has suggested that non-coding microRNAs play a significant role in mediating and modulating chemotherapy resistance, particularly among oral cancers. One recent study found that the upregulation of miR-145 and the downregulation of miR-155 strongly correlated with a limited chemotherapy resistance to Cisplatin, 5-Fluorouracil, and Paclitaxel, although the mechanism(s) responsible for these observations remain unidentified. Using commercially available cell lines of oral squamous cell carcinoma, RNA was isolated, converted into cDNA, and subsequently screened for the expression of downstream targets of miR-145 and miR-155 using qPCR. These results demonstrated the upregulation of miR-21, miR-125, miR-133, miR-365, miR-720, and miR-1246, as well as the downregulation of miR-140, miR-152, miR-218, miR-221, and miR-224. This screening also confirmed the differential expression and regulation of mir-145 and miR-155 among the cell lines with limited chemotherapy resistance (SCC15). In addition, several downstream targets of these specific microRNAs were upregulated by all oral cancer cell lines, such as MBTD1 and FSCN1, or downregulated in all cell lines, such as CLCN3, FLI-1, MRTFB, DAB, SRGAP1, and ABHD17C. However, three miR-145 downstream targets were identified in the least chemotherapy-resistant cells, exhibiting the differential upregulation of KCNA4 and SRGAP2, as well as the downregulation of FAM135A, with this expression pattern not detected in any of the other oral cancer cell lines. These data strongly support that the differential regulation of these three downstream targets may be related to the chemosensitivity of this oral cancer cell line. The potential involvement of these targets must be further investigated to determine how and whether mechanisms of these cellular pathways may be involved in the observed lack of chemotherapy resistance. These data may be important to design targets or treatments to reduce chemotherapy resistance and improve patient treatment outcomes.