SKP2-mediated ubiquitination and degradation of KLF11 promotes osteoarthritis via modulation of JMJD3/NOTCH1 pathway.

Osteoarthritis (OA) is the main cause of cartilage damage and disability. This study explored the biological function of S-phase kinase-associated protein 2 (SKP2) and Kruppel-like factor 11 (KLF11) in OA progression and its underlying mechanisms. C28/I2 chondrocytes were stimulated with IL-1ß to mimic OA in vitro. We found that SKP2, Jumonji domain-containing protein D3 (JMJD3), and Notch receptor 1 (NOTCH1) were upregulated, while KLF11 was downregulated in IL-1ß-stimulated chondrocytes. SKP2/JMJD3 silencing or KLF11 overexpression repressed apoptosis and extracellular matrix (ECM) degradation in chondrocytes. Mechanistically, SKP2 triggered the ubiquitination and degradation of KLF11 to transcriptionally activate JMJD3, which resulted in activation of NOTCH1 through inhibiting H3K27me3. What's more, the in vivo study found that KLF11 overexpression delayed OA development in rats via restraining apoptosis and maintaining the balance of ECM metabolism. Taken together, ubiquitination and degradation of KLF11 regulated by SKP2 contributed to OA progression by activation of JMJD3/NOTCH1 pathway. Our findings provide promising therapeutic targets for OA.

Multitask deep learning for prediction of microvascular invasion and recurrence-free survival in hepatocellular carcinoma based on MRI images.

BACKGROUND AND AIMS: Accurate preoperative prediction of microvascular invasion (MVI) and recurrence-free survival (RFS) is vital for personalised hepatocellular carcinoma (HCC) management. We developed a multitask deep learning model to predict MVI and RFS using preoperative MRI scans. METHODS: Utilising a retrospective dataset of 725 HCC patients from seven institutions, we developed and validated a multitask deep learning model focused on predicting MVI and RFS. The model employs a transformer architecture to extract critical features from preoperative MRI scans. It was trained on a set of 234 patients and internally validated on a set of 58 patients. External validation was performed using three independent sets (n = 212, 111, 110). RESULTS: The multitask deep learning model yielded high MVI prediction accuracy, with AUC values of 0.918 for the training set and 0.800 for the internal test set. In external test sets, AUC values were 0.837, 0.815 and 0.800. Radiologists' sensitivity and inter-rater agreement for MVI prediction improved significantly when integrated with the model. For RFS, the model achieved C-index values of 0.763 in the training set and ranged between 0.628 and 0.728 in external test sets. Notably, PA-TACE improved RFS only in patients predicted to have high MVI risk and low survival scores (p < .001). CONCLUSIONS: Our deep learning model allows accurate MVI and survival prediction in HCC patients. Prospective studies are warranted to assess the clinical utility of this model in guiding personalised treatment in conjunction with clinical criteria.

Identification of flexible Pif1-DNA interactions and their impacts on enzymatic activities.

Flexible regions in biomolecular complexes, although crucial to understanding structure-function relationships, are often unclear in high-resolution crystal structures. In this study, we showed that single-molecule techniques, in combination with computational modeling, can characterize dynamic conformations not resolved by high-resolution structure determination methods. Taking two Pif1 helicases (ScPif1 and BsPif1) as model systems, we found that, besides a few tightly bound nucleotides, adjacent solvent-exposed nucleotides interact dynamically with the helicase surfaces. The whole nucleotide segment possessed curved conformations and covered the two RecA-like domains of the helicases, which are essential for the inch-worm mechanism. The synergetic approach reveals that the interactions between the exposed nucleotides and the helicases could be reduced by large stretching forces or electrostatically shielded with high-concentration salt, subsequently resulting in reduced translocation rates of the helicases. The dynamic interactions between the exposed nucleotides and the helicases underlay the force- and salt-dependences of their enzymatic activities. The present single-molecule based approach complements high-resolution structural methods in deciphering the molecular mechanisms of the helicases.

Psychometric Properties of the Brief Pain Inventory Among Patients With Osteoarthritis Undergoing Total Knee Arthroplasty Surgery.

BACKGROUND: Knee osteoarthritis (OA) is characterized by pain and functional restrictions, necessitating precise and reliable pain evaluation for effective disease surveillance and postoperative treatment appraisal. METHODS: This investigation recruited 110 participants who were slated to receive unilateral total knee arthroplasty (TKA) and administered 3 self-reported questionnaires: the Brief Pain Inventory (BPI), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and 5-level EuroQoL Group's 5-dimension questionnaire (EQ-5D-5L), at baseline and 1 year after surgery. Using standard statistical methods and indicators, the BPI was subjected to a battery of psychometric evaluations, including assessments of reliability, validity, and responsiveness. RESULTS: At baseline, there were no significant ceiling or floor effects observed. Additionally, the internal consistency reliability (Cronbach's alpha) of the BPI was above 0.8, suggesting that the questionnaire items are adequately related to one another. The study found moderate to very strong correlations between the pain and physical function domains of the BPI and Western Ontario and McMaster Universities Osteoarthritis Index, as well as a strong correlation between the functional interference dimension of the BPI and the EQ-5D, supporting the construct validity of the BPI. Also, the BPI was found to be responsive to changes in pain over time, with a responsiveness index ranging from 2.55 to 3.19. CONCLUSION: The BPI assessment tool demonstrated good reliability, validity, and responsiveness in knee osteoarthritis patients who have undergone TKA and can be a useful measurement tool in clinical research to evaluate the effectiveness of pain management strategies and surgical interventions.

Perception of Perioperative Risk for Arthroplasty Patients: A Poll of Chinese Orthopaedic Surgeons.

BACKGROUND: Informed by the precedent of an American Association of Hip and Knee Surgeons (AAHKS) survey, where 95% of participants reported instigating modifications to preoperative risk factors, this study appraised the approach of Chinese arthroplasty surgeons toward patients who had modifiable risks. METHODS: An adaptation of the AAHKS survey tool for a Chinese cohort was undertaken. The survey queried 600 Chinese Society of Hip and Knee Surgeons members on whether the perception of unoptimized medical comorbidities and socioeconomic elements affects the propensity to offer surgical procedures. RESULTS: Out of the distributed surveys, 150 responses were received, culminating in a response rate of 25%. The data illustrate that 98.7% of Chinese surgeons practice restrictions on arthroplasty access for patients who have modifiable risk factors, with notable frequencies for malnutrition (93.3%), anemia (91.3%), recent hyaluronic acid injections (within one month, 88.7%), and corticosteroid injections (within 3 months, 74.7%). Assessment criteria ahead of surgery included limitations such as a body mass index under 40 (47.3%), requirements for smoking cessation (57.3%), an acceptable hemoglobin A1c level (95.3%), and a dependent fasting blood glucose level (88%). Moreover, 87.3% of respondents endorsed the need for additional interventions for certain socioeconomically disadvantaged patients to achieve successful outcomes. A majority of respondents (94.7%) believed that more equitable access to care, facilitated by better-adjusted payment methodologies, could enhance patient outcomes. Current payment schemes were also perceived by a majority to potentially compromise outcomes for patients who have inadequate social support (80.7%), low socioeconomic status (67.3%), and those lacking insurance (72.7%). CONCLUSIONS: The consistency of the almost 99% response rate in addressing modifiable risk factors prior to arthroplasty aligns closely with the reported practices in the AAHKS survey. These findings underscore the shared valuation of preoperative risk factor optimization by Chinese and American arthroplasty surgeons, notwithstanding divergent healthcare system structures.

CT-based intratumoral and peritumoral deep transfer learning features prediction of lymph node metastasis in non-small cell lung cancer.

BACKGROUND: The main metastatic route for lung cancer is lymph node metastasis, and studies have shown that non-small cell lung cancer (NSCLC) has a high risk of lymph node infiltration. OBJECTIVE: This study aimed to compare the performance of handcrafted radiomics (HR) features and deep transfer learning (DTL) features in Computed Tomography (CT) of intratumoral and peritumoral regions in predicting the metastatic status of NSCLC lymph nodes in different machine learning classifier models. METHODS: We retrospectively collected data of 199 patients with pathologically confirmed NSCLC. All patients were divided into training (n = 159) and validation (n = 40) cohorts, respectively. The best HR and DTL features in the intratumoral and peritumoral regions were extracted and selected, respectively. Support Vector Machine (SVM), k-Nearest Neighbors (KNN), Light Gradient Boosting Machine (Light GBM), Multilayer Perceptron (MLP), and Logistic Regression (LR) models were constructed, and the performance of the models was evaluated. RESULTS: Among the five models in the training and validation cohorts, the LR classifier model performed best in terms of HR and DTL features. The AUCs of the training cohort were 0.841 (95% CI: 0.776-0.907) and 0.955 (95% CI: 0.926-0.983), and the AUCs of the validation cohort were 0.812 (95% CI: 0.677-0.948) and 0.893 (95% CI: 0.795-0.991), respectively. The DTL signature was superior to the handcrafted radiomics signature. CONCLUSIONS: Compared with the radiomics signature, the DTL signature constructed based on intratumoral and peritumoral areas in CT can better predict NSCLC lymph node metastasis.

Nuclear receptor coactivator 3 transactivates proinflammatory cytokines in collagen-induced arthritis.

Rheumatoid arthritis (RA) is an autoimmune disorder in which the immune system mistakenly attacks joints. The molecular mechanisms underlying RA pathology are still under investigation. In this study, we discovered overexpression of nuclear receptor coactivator 3 (NCOA3) in the joint tissues of type II collagen-induced arthritis (CIA) mice, an important autoimmune model of human RA. Administration of two NCOA3 inhibitors, gossypol (GSP) and SI-2 hydrochloride (SHC), significantly alleviated inflammation and improved the outcomes of CIA mice. In vivo and in vitro experiments revealed that NCOA3 assembled a transcriptional complex with a histone acetyltransferase p300 and two subunits of nuclear factor kappa B (NF-κB). This complex specifically controlled the expression of proinflammatory cytokine genes by binding to their promoters. Knockdown of NCOA3 or in vitro treatments with GSP and SHC impaired the assembly of NCOA3-p300-NF-κB complex and decreased the expression of proinflammatory cytokine genes. Taken together, our results demonstrated that NCOA3 acts as a mediator of proinflammatory cytokine genes in CIA mice and that inhibition of the NCOA3-p300-NF-κB complex may represent a new avenue for improving RA outcomes.

Plantar Pressure Distribution and Posture Balance During Walking in Individuals with Unilateral Chronic Ankle Instability: An Observational Study.

BACKGROUND Patients with chronic ankle instability (CAI) can present with abnormal gait. The purpose of this study was to evaluate plantar pressure distributions and posture balance during walking in unilateral CAI patients. MATERIAL AND METHODS We recruited 24 unilateral CAI patients and 24 healthy individuals; plantar pressure analysis was conducted using the Footscan® 3D pressure system. The following parameters were assessed and recorded: peak force/weight (PF/W), time to peak force (TPF), time to boundary (TTB), and COP velocity. The differences between the affected and unaffected side of the CAI group and control group were determined. Pearson correlation analysis and univariate analysis was used to investigate the correlation between plantar pressure parameters and related factors. RESULTS The comparison of PF/W showed that the plantar pressure of both sides in the CAI group were laterally distributed. The comparison of TPF, TTB, and COP velocity in different groups showed that the posture balance on the affected side of CAI patient was more impaired than the unaffected side and the control group. Male patients with CAI tend to have better posture balance than females, and a low CAIT score is correlated with poor posture balance. CONCLUSIONS The plantar pressure on both sides in unilateral CAI patients was laterally distributed and their balance function was impaired. It is necessary for CAI patients to receive functional training of both sides during rehabilitation, and plantar pressure analysis is promising for diagnosis and evaluation of CAI.

Hemostatic effect and safety evaluation of oxidized regenerated cellulose in total knee arthroplasty- a randomized controlledtrial.

BACKGROUND: Oxidized regenerated cellulose (ORC) is a type of biodegradable hemostatic material, which has been widely used in the field of surgery. However, its hemostatic effect in patients undergoing total knee arthroplasty (TKA) is uncertain. Accordingly, this study investigated the effectiveness and safety of ORC in patients receiving TKA. METHODS: Seventy patients undergoing unilateral TKA were randomized into blank control group and ORC (2 pieces of ORC placed in the joint cavity) groups. Then, the two groups were compared for primary (perioperative blood loss [total blood loss, intraoperative blood loss, and hidden blood loss] and hemoglobin drop values) and secondary (coagulation indicators, inflammatory indicators,operation time, and complication rates) outcomes. RESULTS: The total blood loss in the ORC group was 902.32 ± 307.82 mL, which was statistically significantly lower than that in the control group (1052.25 ± 308.44 mL) (P < 0.05). Postoperative hidden blood loss was also statistically markedly lower in the ORC group (801.61 ± 298.80 mL) than in the control group (949.96 ± 297.59 mL) (P < 0.05). There was no significant difference between the two groups in terms of coagulation indicators, inflammatory indicators, operation time, and complication rates. CONCLUSION: In conclusion, our prospective RCT study proved that regenerated oxidized cellulose can be used safely in vivo and can effectively reduce postoperative blood loss in patients, which is a potential method for preventing blood loss after TKA. TRIAL REGISTRATION: This prospective RCT was reviewed and approved by the Ethics Committee of Honghui Hospital of Xi'an Jiaotong University (No: 202,211,007) and was designed and conducted according to the rules of the Declaration of Helsinki. Written informed consent was obtained from patients or their legal guardians.

Mismatch sensing by nucleofilament deciphers mechanism of RecA-mediated homologous recombination.

Recombinases polymerize along single-stranded DNA (ssDNA) at the end of a broken DNA to form a helical nucleofilament with a periodicity of ∼18 bases. The filament catalyzes the search and checking for homologous sequences and promotes strand exchange with a donor duplex during homologous recombination (HR), the mechanism of which has remained mysterious since its discovery. Here, by inserting mismatched segments into donor duplexes and using single-molecule techniques to catch transient intermediates in HR, we found that, even though 3 base pairs (bp) is still the basic unit, both the homology checking and the strand exchange may proceed in multiple steps at a time, resulting in ∼9-bp large steps on average. More interestingly, the strand exchange is blocked remotely by the mismatched segment, terminating at positions ∼9 bp before the match-mismatch joint. The homology checking and the strand exchange are thus separated in space, with the strand exchange lagging behind. Our data suggest that the strand exchange progresses like a traveling wave in which the donor DNA is incorporated successively into the ssDNA-RecA filament to check homology in ∼9-bp steps in the frontier, followed by a hypothetical transitional segment and then the post-strand-exchanged duplex.

The Efficacy and Safety of Bionic Tiger Bone Powder for the Treatment of Knee Osteoarthritis in Early Stage: A Randomized, Double-Blind, Placebo-Controlled, Multicenter Clinical Trial.

Objective: This study evaluated the efficacy and safety of bionic tiger bone powder (Jintiange) in comparison to placebo in treating knee osteoarthritis osteoporosis. Methods: A total of 248 patients were randomly allocated to a Jintiange group or a placebo group, undergoing 48 weeks of double-blind treatment. The Lequesne index, clinical symptoms, safety index (adverse events), and Patient's Global Impression of Change score were recorded at pre-determined time intervals. All P values ≤ .05 were deemed statistically significant. Results: Both groups showed a decreasing trend in the Lequesne index, with the Jintiange group's reduction significantly larger from the 12th week (P ≤ .01). Similarly, the effective rate of Lequesne score in the Jintiange group was significantly higher (P < .001). After 48 weeks, clinical symptom score differences between the Jintiange group (2.46 ± 1.74) and the placebo group (1.51 ± 1.73) were statistically significant (P < .05), as were differences in the Patient's Global Impression of Change score (P < .05). Adverse drug reactions were minimal with no significant difference between the groups (P > .05). Conclusion: Jintiange demonstrated superior efficacy over placebo in treating knee osteoporosis, with comparable safety profiles. Findings warrant further comprehensive real-world studies.

Dynamic structural insights into the molecular mechanism of DNA unwinding by the bacteriophage T7 helicase.

The hexametric T7 helicase (gp4) adopts a spiral lock-washer form and encircles a coil-like DNA (tracking) strand with two nucleotides bound to each subunit. However, the chemo-mechanical coupling mechanism in unwinding has yet to be elucidated. Here, we utilized nanotensioner-enhanced Förster resonance energy transfer with one nucleotide precision to investigate gp4-induced unwinding of DNA that contains an abasic lesion. We observed that the DNA unwinding activity of gp4 is hindered but not completely blocked by abasic lesions. Gp4 moves back and forth repeatedly when it encounters an abasic lesion, whereas it steps back only occasionally when it unwinds normal DNA. We further observed that gp4 translocates on the tracking strand in step sizes of one to four nucleotides. We propose that a hypothetical intermediate conformation of the gp4-DNA complex during DNA unwinding can help explain how gp4 molecules pass lesions, providing insights into the unwinding dynamics of gp4.

Subnanometer-Precision Measurements of Transmembrane Motions of Biomolecules in Plasma Membranes Using Quenchers in Extracellular Environment.

Characterization of biomolecular dynamics at cellular membranes lags far behind that in solutions because of challenges to measure transmembrane trafficking with subnanometer precision. Herein, by introducing nonfluorescent quenchers into extracellular environment of live cells, we adopted Förster resonance energy transfer from one donor to multiple quenchers to measure positional changes of biomolecules in plasma membranes. We demonstrated the method by monitoring flip-flops of individual lipids and by capturing transient states of the host defense peptide LL-37 in plasma membranes. The method was also applied to investigate the interaction of the necroptosis-associated protein MLKL with plasma membranes, showing a few distinct depths of MLKL insertion. Our method is especially powerful to quantitate the dynamics of proteins at the cytosolic leaflets of plasma membranes which are usually not accessible by conventional techniques. The method will find wide applications in the systematic analysis of fundamental cellular processes at plasma membranes.

Circ_AFF2 facilitates proliferation and inflammatory response of fibroblast-like synoviocytes in rheumatoid arthritis via the miR-375/TAB2 axis.

Circular RNAs (circRNAs) have been implicated in the pathological regulation of human diseases by acting as microRNA (miRNA) sponges to affect gene expression. CircRNA Fragile Mental Retardation 2 (circ_AFF2) was dysregulated in rheumatoid arthritis (RA), but little is known about its specific function and hidden molecular mechanism in RA. Circ_AFF2, miR-375 and TAK1-binding 2 (TAB2) expression levels were determined through the quantitative real-time polymerase chain reaction (qRT-PCR). Flow cytometry was performed to analyze cell cycle and apoptosis. Cell proliferation detection was conducted by 3-(4, 5-dimethylthiazol-2-y1)-2, 5-diphenyl tetrazolium bromide (MTT) assay. The protein levels were measured using western blot. Inflammatory response was evaluated by enzyme-linked immunosorbent assay (ELISA). RNA pull-down assay was used to select the miRNA target of circ_AFF2. The interaction between miR-375 and circ_AFF2 or TAB2 was analyzed using the dual-luciferase reporter assay. Contrasted to normal samples and fibroblast-like synoviocytes (FLS), circ_AFF2 expression was upregulated in RA blood samples and FLS-RA cells. Cell cycle, proliferation and inflammatory response were blocked while apoptosis was promoted in FLS-RA after the downregulation of circ_AFF2. In addition, circ_AFF2 could interact with miR-375 and the function of circ_AFF2 was achieved by sponging miR-375 in FLS-RA cells. Moreover, TAB2 was a target of miR-375 and miR-375 repressed RA progression by decreasing TAB2 expression in FLS-RA cells. More importantly, circ_AFF2 promoted the expression of TAB2 by targeting miR-375. These findings clarified that circ_AFF2 induced cell progression, inflammatory response in FLS-RA cells via the miR-375/TAB2 axis. Circ_AFF2 could be used as a biomarker in the diagnosis and treatment of RA.

Imaging Features of Sclerosing Angiomatoid Nodular Transformation in Spleen.

PURPOSE: The purpose of this study was to evaluate the features of sclerosing angiomatoid nodular transformation (SANT) in spleen on the imaging of computed tomography (CT) and magnetic resonance (MR). MATERIALS AND METHODS: From July 2006 to April 2017, 12 patients with SANT confirmed by pathology were evaluated in a retrospective study. Eight patients were with CT imaging only, 2 patients were with MR imaging only, and 2 patients were with both CT and MR. Three professional senior radiologists analyzed the imaging features on CT and MR. The main characteristic analysis included size, margin, density, signal intensity, and enhancement pattern. The significant enhancement was defined as the degree of enhancement of lesion that is higher than the surrounding spleen parenchyma, and the mild enhancement was defined as the degree of enhancement of lesion that is lower than the surrounding spleen parenchyma. RESULTS: All the 12 patients (5 men, 7 women; mean age, 45.8 years; age range, 21-62 years) presented as single lesion without special clinical symptoms. The range of lesions on diameter was from 25 to 80 mm. On CT images, 9 (90%) of 10 presented as hypodense in comparison with the parenchyma of spleen, 1 (10%) of 10 presented as isodense, and calcification was observed in 4 (40%) of 10 cases. On MR images, 4 (100%) of 4 manifested heterogeneous hypointensity on in-phase sequence and 3 (75%) of 4 performed as isointensity on out-of-phase sequence of T1-weighted. On the sequences of T2-weighted and diffusion-weighted image, 4 (100%) of 4 showed hypointensity. On CT and MR enhancement images, the number of significant enhancement and mild enhancement was 2 and 10, respectively. Seven (58%) of 12 showed progressive enhancement with the pattern of "spoke-wheel." CONCLUSIONS: Imaging features on CT and MR have a high diagnostic value for SANT, especially when CT combined with MR examination.

Treatment of posterolateral tibial plateau fractures through fibular osteotomy approach.

The best approach for treating posterolateral tibial plateau fractures remains controversial. The aim of the present study was to evaluate the outcomes of patients with posterolateral tibial plateau fractures after open reduction and internal fixation with the fibular osteotomy approach. Between January 2009 and July 2012, twelve patients with posterolateral tibial plateau fracture were treated using the fibular osteotomy approach with a proximal tibia locking compression plate. The epidemiological data, operation details, and clinical outcomes over 25.6 ± 2.1 months (range, 22-38 months) of follow-up were prospectively collected and analyzed. The average surgical duration was 92.5 ± 14.5 min (range, 83-107 min). An anatomical reduction rate of 91.7% (11/12) was observed, although one patient with a lateral comminuted fracture and dislocation had a 2-mm joint surface depression postoperatively. The average fracture healing time was 11.6 ± 3.1 weeks (range, 8-15 weeks), with an average hospital for special surgery knee score of 94.1 ± 3.2 points (range, 80-100 points), an average knee flexion of 118.6° ± 18.1° (range, 96°-138°) and an average knee extension of 1.9° ± 2.2° (range, 0°-6.3°). No complications were found. The fibular osteotomy approach with a proximal tibial compression plate can produce a satisfactory clinical outcome for patients with posterolateral tibial plateau fractures.

Detecting Single-Molecule Dynamics on Lipid Membranes with Quenchers-in-a-Liposome FRET.

Tracking membrane-interacting molecules and visualizing their conformational dynamics are key to understanding their functions. It is, however, challenging to accurately probe the positions of a molecule relative to a membrane. Herein, a single-molecule method, termed LipoFRET, is reported to assess interplay between molecules and liposomes. It takes advantage of FRET between a single fluorophore attached to a biomolecule and many quenchers in a liposome. This method was used to characterize interactions between α-synuclein (α-syn) and membranes. These results revealed that the N-terminus of α-syn inserts into the membrane and spontaneously transitions between different depths. In contrast, the C-terminal tail of α-syn is regulated by calcium ions and floats in solution in two conformations. LipoFRET is a powerful tool to investigate membrane-interacting biomolecules with sub-nanometer precision at the single-molecule level.

Watching Three-Dimensional Movements of Single Membrane Proteins in Lipid Bilayers.

It is challenging to assess protein-membrane interactions because of the lack of appropriate tools to detect position changes of single proteins in the ∼4 nm range of biological membranes. We developed an assay recently, termed surface-induced fluorescence attenuation (SIFA). It is able to track both vertical and lateral dynamic motion of singly labeled membrane proteins in supported lipid bilayers. Similar to the FRET (fluorescence resonance energy transfer) principle, SIFA takes advantage of the energy transfer from a fluorophore to a light-absorbing surface to determine the distance at 2-8 nm away from the surface. By labeling a protein with a proper fluorophore and using graphene oxide as a two-dimensional quencher, we showed that SIFA is capable of monitoring three-dimensional movements of the fluorophore-labeled protein not only inside but also above the lipid bilayer atop the graphene oxide. Our data show that SIFA is a well-suited method to study the interplay between proteins and membranes.

Identification of Novel Target for Osteosarcoma by Network Analysis.

BACKGROUND Osteosarcoma (OS) is a highly complicated bone cancer involving imbalance of signaling transduction networks in cells. Development of new anti-osteosarcoma drugs is very challenging, mainly due to lack of known key targets. MATERIAL AND METHODS In this study, we attempted to reveal more promising targets for drug design by "Target-Pathway" network analysis, providing the new therapeutic strategy of osteosarcoma. The potential targets used for the treatment of OS were selected from 4 different sources: DrugBank, TCRD database, dbDEMC database, and recent scientific literature papers. Cytoscape was used for the establishment of the "Target-Pathway" network. RESULTS The obtained results suggest that tankyrase 2 (TNKS2) might be a very good potential protein target for the treatment of osteosarcoma. An in vitro MTT assay proved that it is an available option against OS by targeting the TNKS2 protein. Subsequently, cell cycle and apoptosis assay by flow cytometry showed the TNKS2 inhibitor can obviously induce cell cycle arrest, apoptosis, and mitotic cell death. CONCLUSIONS Tankyrase 2 (TNKS2), a member of the multifunctional poly(ADP-ribose) polymerases (PARPs), could be a very useful protein target for the treatment of osteosarcoma.

Pif1 is a force-regulated helicase.

Pif1 is a prototypical member of the 5' to 3' DNA helicase family conserved from bacteria to human. It has a high binding affinity for DNA, but unwinds double-stranded DNA (dsDNA) with a low processivity. Efficient DNA unwinding has been observed only at high protein concentrations that favor dimerization of Pif1. In this research, we used single-molecule fluorescence resonance energy transfer (smFRET) and magnetic tweezers (MT) to study the DNA unwinding activity of Saccharomyces cerevisiae Pif1 (Pif1) under different forces exerted on the tails of a forked dsDNA. We found that Pif1 can unwind the forked DNA repetitively for many unwinding-rezipping cycles at zero force. However, Pif1 was found to have a very limited processivity in each cycle because it loosened its strong association with the tracking strand readily, which explains why Pif1 cannot be observed to unwind DNA efficiently in bulk assays at low protein concentrations. The force enhanced the unwinding rate and the total unwinding length of Pif1 significantly. With a force of 9 pN, the rate and length were enhanced by more than 3- and 20-fold, respectively. Our results imply that the DNA unwinding activity of Pif1 can be regulated by force. The relevance of this characteristic of Pif1 to its cellular functions is discussed.