Protein kinase Cα/β inhibitor Gö6976 promotes PC12 cell adhesion and spreading through membrane recruitment and activation of protein kinase Cδ

Three interfaces of the dental implant system and their clinical effects on hard and soft tissues

Anatomically, the human tooth has structures both embedded within and forming part of the exterior surface of the human body. When a tooth is lost, it is often replaced by a dental implant, to facilitate the chewing of food and for esthetic purposes. For successful substitution of the lost tooth, hard tissue should be integrated into the implant surface. The microtopography and chemistry of the implant surface have been explored with the aim of enhancing osseointegration. Additionally, clinical implant success is dependent on ensuring that a barrier, comprising strong gingival attachment to an abutment, does not allow the infiltration of oral bacteria into the bone-integrated surface. Epithelial and connective tissue cells respond to the abutment surface, depending on its surface characteristics and the materials from which it is made. In particular, the biomechanics of the implant-abutment connection structure (i.e., the biomechanics of the interface between implant and abutment surfaces, and the screw mechanics of the implant-abutment assembly) are critical for both the soft tissue seal and hard tissue integration. Herein, we discuss the clinical importance of these three interfaces: bone-implant, gingiva-abutment, and implant-abutment.

The effect of Gö6976 on chronic myeloid leukemia in vitro and in vivo

Objectives: Chronic myeloid leukemia (CML) is a malignant tumor of the blood system. Gö6976, as a type of indolocarbazole and shows strong antitumor effects, but there have been no reports on the effect of Gö6976 on CML. The objectives of this research were: (1) to explore the impact of Gö6976 on CML in vitro and in vivo; and (2) to explore the drug toxicity of Gö6976 to normal cells and animals.Methods:K562 cells and CML mice were used to explore the effect of Gö6976 on CML. Peripheral blood mononuclear cells (PBMCs), CD34+ cells, and healthy mice were used to explore the drug toxicity of Gö6976.Results: Cell experiments showed that Gö6976 could inhibit the proliferation of K562 cells and enhance the inhibitory effects of imatinib at 5 μM and 10 μM, but it had little effect on CD34+ cells or PBMCs at concentrations less than 5 μM. Animal experiments showed that 2.5 mg/kg Gö6976 could effectively inhibit the development of CML in mice, and it had almost no effects on healthy mice at 2.5 mg/kg and 10 mg/kg.Discussion: Because of the direct inhibitory effect of Gö6976 on CML and its pharmacological enhancement effect on imatinib, it is foreseeable that Gö6976 could become a new type of anti-CML medicine. And the further research is needed.Conclusion: Our findings verified that Gö6976 could effectively inhibit CML in vitro and in vivo, and it is almost nontoxic to hematopoietic cells, immune cells, and healthy mice.

The laminin-211-derived PPFEGCIWN motif accelerates wound reepithelialization and increases phospho-FAK-Tyr397 and Rac1-GTP levels in a rat excisional wound splinting model

We previously reported that the PPFEGCIWN motif (Ln2-LG3-P2-DN3), residues 2678-2686 of the human laminin α2 chain, promotes cell attachment of normal human epidermal keratinocytes (NHEKs) and dermal fibroblasts (NHDFs); however, its in vivo effects on cutaneous wound healing have not yet been examined. In this study, we sought to determine whether Ln2-LG3-P2-DN3 could promote full-thickness cutaneous wound healing by accelerating wound reepithelialization and wound closure in vivo. Ln2-LG3-P2-DN3 had significantly higher cell attachment and spreading activities than vehicle or scrambled peptide control in both NHEKs and NHDFs in vitro. The wound area was significantly smaller in rats treated with Ln2-LG3-P2-DN3 than in those treated with vehicle or scrambled peptide in the early phase of wound healing. Furthermore, Ln2-LG3-P2-DN3 significantly accelerated wound reepithelialization relative to vehicle or scrambled peptide and promoted FAK-Tyr397 phosphorylation and Rac1 activation. Collectively, our findings suggest that the PPFEGCIWN motif has potential as a therapeutic agent for cutaneous regeneration via the acceleration of wound reepithelization and wound closure.

Selective regulation of osteoclast adhesion and spreading by PLCγ/PKCα-PKCδ/RhoA-Rac1 signaling

Bone resorption by multinucleated osteoclasts is a multistep process involving adhesion to the bone matrix, migration to resorption sites, and formation of sealing zones and ruffled borders. Macrophage colony-stimulating factor (M-CSF) and osteopontin (OPN) have been shown to be involved in the bone resorption process by respective activation of integrin αvβ3 via “inside-out” and “outside-in” signaling. In this study, we investigated the link between signal modulators known to M-CSF- and OPN-induced osteoclast adhesion and spreading. M-CSF- and OPN-induced osteoclast adhesion was achieved via activation of stepwise signals, including integrin αvβ3, PLCγ, PKCδ, and Rac1. Osteoclast spreading induced by M-CSF and OPN was shown to be controlled via sequential activation, consistent with the osteoclast adhesion processes. In contrast to osteoclast adhesion, osteoclast spreading induced by M-CSF and OPN was blocked via activation of PLCγ/PKCα/RhoA signaling. The combined results indicate that osteoclast adhesion and spreading are selectively regulated via PLCγ/PKCα-PKCδ/RhoA-Rac1 signaling.

Protein kinase C inhibitors: a patent review (2008 - 2009)

INTRODUCTION

The protein kinase C (PKC) is a family of multifunctional isoenzymes involved in apoptosis, migration, adhesion, tumorgenesis, cardiac hypertrophy, angiogenesis, platelet function and inflammation. It also plays a vital role in the regulation of signal transduction, cell proliferation and differentiation through positive and negative regulation of the cell cycle. In this work, we reviewed the existing PKC inhibitors and several patents linked to PKC inhibitors.

AREAS COVERED

Thorough survey on the PKC inhibitors having clinical importance and patents filed for these inhibitors from 2008 - 2009 is reported.

EXPERT OPINION

PKCs are highly potential therapeutic targets for treating diabetic complications, oncological, inflammatory, immunological and dermatological disorders. The clinical trial candidates of PKCs mainly target the catalytic domain, which is highly conserved throughout the PKC family making it difficult to target a particular isoform selectively. Relatively less chemical space and fewer bisubstrate inhibitors targeting both ATP and regulatory domain are explored for PKCs, more research in these areas will be helpful in overcoming existing problems.

miR-26a plays an important role in cell cycle regulation in ACTH-secreting pituitary adenomas by modulating protein kinase Cδ

The functional aftermath of microRNA (miRNA) dysregulation in ACTH-secreting pituitary adenomas has not been demonstrated. miRNAs represent diagnostic and prognostic biomarkers as well as putative therapeutic targets; their investigation may shed light on the mechanisms that underpin pituitary adenoma development and progression. Drugs interacting with such pathways may help in achieving disease control also in the settings of ACTH-secreting pituitary adenomas. We investigated the expression of 10 miRNAs among those that were found as most dysregulated in human pituitary adenoma tissues in the settings of a murine ACTH-secreting pituitary adenoma cell line, AtT20/D16v-F2. The selected miRNAs to be submitted to further investigation in AtT20/D16v-F2 cells represent an expression panel including 5 up-regulated and 5 down-regulated miRNAs. Among these, we selected the most dysregulated mouse miRNA and searched for miRNA targets and their biological function. We found that AtT20/D16v-F2 cells have a specific miRNA expression profile and that miR-26a is the most dysregulated miRNA. The latter is overexpressed in human pituitary adenomas and can control viable cell number in the in vitro model without involving caspase 3/7-mediated apoptosis. We demonstrated that protein kinase Cδ (PRKCD) is a direct target of miR-26a and that miR26a inhibition delays the cell cycle in G1 phase. This effect involves down-regulation of cyclin E and cyclin A expression via PRKCD modulation. miR-26a and related pathways, such as PRKCD, play an important role in cell cycle control of ACTH pituitary cells, opening new therapeutic possibilities for the treatment of persistent/recurrent Cushing's disease.