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The major goal in restorative dentistry is to develop a true regenerative approach that fully recovers hydroxyapatite crystals within the caries lesion. Recently, a rationally designed self-assembling peptide P 11 -4 (Ace-QQRFEWEFEQQ-NH 2 ) has been developed to enhance remineralization on initial caries lesions, yet its applicability on dentin tissues remains unclear. Thus, the present study investigated the interaction of P 11 -4 with the organic dentin components as well as the effect of P 11 -4 on the proteolytic activity, mechanical properties of the bonding interface, and nanoleakage evaluation to artificial caries-affected dentin. Surface plasmon resonance and atomic force microscopy indicated that P 11 -4 binds to collagen type I fibers, increasing their width from 214 ± 4 nm to 308 ± 5 nm ( P < 0.0001). P 11 -4 also increased the resistance of collagen type I fibers against the proteolytic activity of collagenases. The immediate treatment of artificial caries-affected dentin with P 11 -4 enhanced the microtensile bonding strength of the bonding interface ( P < 0.0001), reaching values close to sound dentin and decreasing the proteolytic activity at the hybrid layer; however, such effects decreased after 6 mo of water storage ( P < 0.05). In conclusion, P 11 -4 interacts with collagen type I, increasing the resistance of collagen fibers to proteolysis, and improves stability of the hybrid layer formed by artificial caries-affected dentin.

Background: BRN2 transcription factor is associated with the development of malignant melanoma. The cytotoxic activities and cell death mechanism against B16F10-Nex2 cells were determined with synthetic peptide R18H derived from the POU domain of the BRN2 transcription factor., Objective: To determine the cell death mechanisms and in vivo activity of peptide R18H derived from the POU domain of the BRN2 transcription factor against B16F10-Nex2 cells., Methods: Cell viability was determined by the MTT method. C57Bl/6 mice were challenged with B16F10-Nex2 cells and treated with R18H. To identify the type of cell death, we used TUNEL assay, Annexin V and PI, Hoechst, DHE, and determination of caspase activation and cytochrome c release. Transmission electron microscopy was performed to verify morphological alterations after peptide treatment., Results: Peptide R18H displayed antitumor activity in the first hours of treatment and the EC50% was calculated for 2 and 24h, being 0.76 ± 0.045 mM and 0.559 ± 0.053 mM, respectively. After 24h apoptosis was evident, based on DNA degradation, chromatin condensation, increase of superoxide anion production, phosphatidylserine translocation, activation of caspases 3 and 8, and release of extracellular cytochrome c in B16F10-Nex2 cells. The peptide cytotoxic activity was not affected by necroptosis inhibitors and treated cells did not release LDH in the extracellular medium. Moreover, in vivo antitumor activity was observed following treatment with peptide R18H., Conclusion: Peptide R18H from BRN2 transcription factor induced apoptosis in B16F10-Nex2 and displayed antitumor activity in vivo., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)