Intra-Articular Biomechanical Changes of the Meniscus and Ligaments During Stance Phase of Gait Circle after Different Anterior Cruciate Ligament Reconstruction Surgical Procedures: A Finite Element Analysis.

OBJECTIVE: The debate on the superiority of single- or double-bundle for anterior cruciate ligament reconstruction has not ceased. The comparative studies on intra-articular biomechanics after different surgical reconstructions are rare. This study is to evaluate the biomechanical stress distribution intra-knee after single- and double-bundle anterior cruciate ligament reconstruction by three-dimensional finite element analysis, and to observe the change of stress concentration under the condition of vertical gradient loads. METHODS: In this study, magnetic resonance imaging data were extracted from patients and healthy controls for biomechanical analysis. Patients included in the three models were matched in age and sex. The strength and distribution of induced stresses were analyzed in two frequently used procedures, anatomical single-bundle anterior cruciate ligament reconstruction and anatomical double-bundle anterior cruciate ligament reconstruction, using femoral-graft-tibial system under different loads, to mimic a post-operation mechanical motion. The three-dimensional finite-element models for normal ligament and two surgical methods were applied. A vertical force simulating daily walking was performed on the models to assess the interfacial stresses and displacements of intra-articular tissues and ligaments. The evaluation results mainly included the stress of each part of ligament and meniscus. The stress values of different parts of three models were extracted and compared. RESULTS: The stress of ligament/graft at femoral side of three finite-element models was significantly higher than at tibial side, while the highest level was observed in single-bundle reconstruction finite-element model. With the increase of force, the maximum stress in the medial (7.1-7.1 MPa) and lateral (4.9-7.4 MPa) meniscus of single-bundle reconstruction finite-element model shifted from the anterior horn to the central area (p = 0.0161, 0.0479, respectively). The stress was shown to be at a lower level at femoral side and posterior cruciate ligament of intra-knee in two reconstruction finite-element models than that in normal finite-element models, while presented higher level at the tibial side than normal knee (p = 0.3528). The displacement of the femoral side and intra-knee areas in reconstruction finite-element models was greater than that in normal finite-element model (p = 0.0855). CONCLUSION: Compared with the single-bundle technique, the graft of double-bundle anterior cruciate ligament reconstruction has better stress dissipation effect and can prevent postoperative meniscus tear more effectively.

Discovery of 2H-benzo[b][1,4]oxazin-3(4H)-one derivatives as potent and selective CDK9 inhibitors that enable transient target engagement for the treatment of hematologic malignancies.

Cyclin-dependent kinase 9 (CDK9) is a transcriptional regulator and a potential therapeutic target in hematologic malignancies. Selective and transient CDK9 inhibition reduces Mcl-1 expression and induces apoptosis in Mcl-1-dependent tumor cells for survival. Here, we describe our efforts to discover a novel series of 2H-benzo[b][1,4]oxazin-3(4H)-one as CDK9 inhibitors. Compound 32k was identified as a selective CDK9 inhibitor with short pharmacokinetic and physicochemical properties suitable for intravenous administration. Short-term treatment with 32k resulted in a rapid dose-dependent decrease in cellular p-Ser2-RNAPII, Mcl-1 and c-Myc, leading to apoptosis in the MV4-11 cell line. Correspondingly, significant in vivo antitumor efficacy was observed in xenograft models derived from multiple hematological tumors with intermittent 32k dosing. These results provide evidence that selective transient CDK9 inhibitors could be used for the treatment of hematologic malignancies.

Discovery of N-(4-(3-isopropyl-2-methyl-2H-indazol-5-yl)pyrimidin-2-yl)-4-(4-methylpiperazin-1-yl)quinazolin-7-amine as a Novel, Potent, and Oral Cyclin-Dependent Kinase Inhibitor against Haematological Malignancies.

Hematologic malignancies (HM) start in blood forming tissue or in the cells of the immune system. Cyclin-dependent kinases (CDKs) regulate cell cycle progression, and some of them control cellular transcription. CDK inhibition can trigger apoptosis and could be particularly useful in hematological malignancies. Herein, we describe our efforts toward the discovery of a novel series of quinazoline derivatives as CDK inhibitors. Intensive structural modifications lead to the identification of compound 37d as the most active inhibitors of CDKs 1, 2, 4, 8 and 9 with balancing potency and selectivity against CDKs. Further biological studies revealed that compound 37d can arrest the cell cycle and induce apoptosis via activating PARP and caspase 3. More importantly, compound 37d showed good antitumor efficacy in multiple HM mice xenograft models with no obvious toxicity. These results indicated that CDK 1, 2, 4, 8, and 9 inhibitors could be potentially used to treat certain hematologic malignancies.

The discovery of quinoline derivatives, as NF-κB inducing kinase (NIK) inhibitors with anti-inflammatory effects in vitro, low toxicities against T cell growth.

NIK is a critical regulatory protein of the non-classical NF-kB pathway, and its dysregulated activation has been proved to be one of the pathogenic factors in a variety of autoimmune diseases and inflammatory diseases. Nevertheless, its corresponding development of inhibitors faces many obstacles, including the lack of structure types of known inhibitors, immature activity evaluation methods of compounds in vitro. In this study, a series of quinoline derivatives were obtained through rational design and chemical synthesis. Among them, the representative compounds 17c and 24c have excellent inhibitory activities on LPS-induced macrophage (J774) nitric oxide release and anti-Con A-stimulated primary T cell proliferation. This evaluation method has good universality and overcomes the obstacles mentioned above, which are faced by the current inhibitor research to a certain extent. Besides, the compound's toxicity against the growth of T cells under non-stress conditions was evaluated, for the first time, as an indicator for the investigation to avoid potential safety risks. Pharmacokinetic properties evaluation of the less toxic compound 24c confirmed its good metabolic behavior (especially oral properties, F% = 21.7%), and subsequent development value.

Identification of N-Phenyl-7H-pyrrolo[2,3-d]pyrimidin-4-amine Derivatives as Novel, Potent, and Selective NF-κB Inducing Kinase (NIK) Inhibitors for the Treatment of Psoriasis.

A series of N-phenyl-7H-pyrrolo[2,3-d]pyrimidin-4-amine derivatives with NF-κB inducing kinase (NIK) inhibitory activity were obtained through structure-based drug design and synthetic chemistry. Among them, 4-(3-((7H-pyrrolo[2,3-d]pyrimidin-4-yl)amino)-4-morpholinophenyl)-2-(thiazol-2-yl)but-3-yn-2-ol (12f) was identified as a highly potent NIK inhibitor, along with satisfactory selectivity. The pharmacokinetics of 12f and its ability to inhibit interleukin 6 secretion in BEAS-2B cells were better than compound 1 developed by Amgen. Oral administration of different doses of 12f in an imiquimod-induced psoriasis mouse model showed effective alleviation of psoriasis, including invasive erythema, swelling, skin thickening, and scales. The underlying pathological mechanism involved attenuation of proinflammatory cytokine and chemokine gene expression, and the infiltration of macrophages after the treatment of 12f. This work provides a foundation for the development of NIK inhibitors, highlighting the potential of developing NIK inhibitors as a new strategy for the treatment of psoriasis.

Discovery of coumarin derivatives as potent and selective cyclin-dependent kinase 9 (CDK9) inhibitors with high antitumour activity.

Specific inhibition of CDK9 is considered a promising strategy for developing effective anticancer therapeutics. However, most of the reported CDK9 inhibitors are still at an early stage of development and lack selectivity against other CDKs. Herein, we discovered coumarin derivative 30i as a potent CDK9 inhibitor with high selectivity (8300-fold over CDK7). Binding mode analysis illustrated that the substituent coumarin moiety is a critical group for CDK9 selectivity by occupying a flexible hinge/αD region, which is sterically hindered in other CDKs. Compound 30i showed excellent cellular antiproliferative activity, moderate pharmacokinetic property and low hERG inhibition. Moreover, 30i significantly induced tumour growth inhibition in a dose-dependent manner without causing an obvious loss of body weight in an MV4-11 xenograft mice model. Altogether, these results suggest that 30i may serve as a potential acute myeloid leukaemia (AML) therapeutics by selectively targeting CDK9.

Phase evolution of ultra-thin Ni silicide films on CF4 plasma immersion ion implanted Si.

We present a systematic study on the effects of CF4 plasma immersion ion implantation (PIII) in Si on the phase evolution of ultra-thin Ni silicides. For 3 nm Ni, NiSi2 was formed on Si substrates with and without CF4 PIII at temperature as low as 400 °C. For 6 nm Ni, NiSi was formed on pure Si, while epitaxial NiSi2 was obtained on CF4 PIII Si. The incorporation of C and F atoms in the thin epitaxial NiSi2 significantly reduces the layer resistivity. Increasing the Ni thickness to 8 nm results in the formation of NiSi, where the thermal stability of NiSi, the NiSi/Si interface and Schottky contacts are significantly improved with CF4 PIII. We suggest that the interface energy is lowered by the F and C dopants present in the layer and at the interface, leading to phase evolution of the thin Ni silicide.