Diagnostic and prognostic values of MMP-9 expression in ovarian cancer: A study based on bioinformatics analysis and meta-analysis.

This study aims to explore the expression of matrix metalloproteinase-9 (MMP-9) associated with both diagnostic and prognostic value in ovarian cancer by meta-analysis and bioinformatics analyses. We investigated the prognostic value of MMP-9 expression in ovarian cancer based on The Cancer Genome Atlas. Five databases were used to collect records about MMP-9 expression related to diagnostic and prognostic values in ovarian cancer from inception to June 2022. Using Stata 15.0 software, hazard ratio (HR) and odds ratio (OR) were calculated as the effect index of prognosis. We chose the pooled sensitivity, specificity, and area under the curve (AUC) to judge the diagnostic utility of MMP-9 for ovarian cancer. A total of 23 studies on prognosis, and five studies on diagnosis were entered into the meta-analysis. These suggest that high MMP-9 expression was detrimental to the overall survival of patients with ovarian cancer (HR = 1.34; 95% confidence interval (CI) 1.08∼1.66; P<0.01). High MMP-9 expression increased the risk of tumor stage (OR = 3.66; 95% CI 1.89∼7.07), but was not related to the tumor grade of ovarian cancer (P>0.05). The pooled analysis of serum MMP-9 diagnosing for ovarian cancer gave the pooled sensitivity, specificity, and AUC the values of 0.72 (95% CI 0.61∼0.81), 0.81 (95% CI 0.77∼0.85), and 0.84 (95% CI 0.81∼0.87), respectively. High MMP-9 expression can increase the tumor stage, and a correlation exists between high MMP-9 expression and poor prognosis in patients with ovarian cancer. Also, serum MMP-9 has a good diagnostic value for ovarian cancer.

LINC00704 contributes to the proliferation and accelerates the cell cycle of nasopharyngeal carcinoma cells via regulating ETS1/CDK6 axis.

This study is aimed at exploring the biological functions and related mechanism of long noncoding RNA 704 (LINC00704) in the proliferation and cell cycle progression of nasopharyngeal carcinoma (NPC) cells. The expression of LINC00704 in NPC tissues and cells was quantified by quantitative real-time polymerase chain reaction (qRT-PCR). After LINC00704 was overexpressed or knocked down in NPC cell lines, cell counting kit-8 (CCK-8) assay, 5-bromo-2'-deoxyuridine assay, flow cytometry assay, and Transwell assay were adopted to detect the proliferation, cell cycle progression, migration, and invasion of NPC cells. The interaction between LINC00704 and ETS proto-oncogene 1 (ETS1) was verified by bioinformatics analysis, RNA pull-down assay, and RNA immunoprecipitation assay. Dual-luciferase reporter gene assay and chromatin immunoprecipitation followed by qPCR analysis were used to verify the binding status between ETS1 and the promoter region of cyclin-dependent kinase 6 (CDK6). The regulatory effects of LINC00704 and ETS1 on CDK6 expression were detected by Western blot. LINC00704 expression was elevated in NPC tissues and cells, which was significantly correlated with the advanced TNM stage and poor differentiation. LINC00704 overexpression promoted the multiplication, migration, and invasion of NPC cells and blocked the cell cycle progression while knocking down LINC00704 worked oppositely. LINC00704 could bind to ETS1, thus promoting CDK6 transcription. Knocking down LINC00704 inhibited the CDK6 expression in NPC cells. LINC00704 promotes CDK6 transcription by recruiting ETS1 to the promoter region of CDK6, thus promoting the malignant progression of NPC.

Circular RNA circ_0000517 Facilitates The Growth and Metastasis of Non-Small Cell Lung Cancer by Sponging miR-326/miR-330-5p.

OBJECTIVE: There is growing evidence showing that circular RNAs (circRNAs) are crucial regulators in modulating the biological behavior of tumors. This work is aimed to probe the role of circ_0000517 in non-small cell lung cancer (NSCLC) and to elucidate its mechanism of action. MATERIALS AND METHODS: In this experimental study, the differentially expressed circRNAs in NSCLC were screened using the GEO database (GSE158695). Circ_0000517, miR-326, miR-330-5p, and MMP2 expression levels were determined by quantitative real-time polymerase chain reaction (qRT-PCR) analysis and Western blot. The proliferation, apoptosis, migration, and invasion of NSCLC cells were detected by CCK-8, flow cytometry, and transwell assays. RNA immunoprecipitation (RIP), RNA pull-down, and dual-luciferase reporter gene assays were performed to clarify the association between the circ_0000517 and miR-326/miR-330-5p. RESULTS: Circ_0000517 was shown to be up-regulated in NSCLC tissues and cell lines. The up-regulation of circ_0000517 is closely associated with advanced clinical stage of cancer, lymph node metastasis, and poor prognosis in NSCLC patients. Circ_0000517 knockdown impeded the proliferation, migration, and invasion of NSCLC cells and enhanced their apoptosis. Mechanistically, circ_0000517 was demonstrated to up-regulate MMP2 expression via decoying miR-326 and miR-330-5p to facilitate the malignant biological behaviors of NSCLC cells. CONCLUSION: This work reveals that circ_0000517 is implicated in NSCLC cell growth and metastasis through the modulation of miR-326/miR-330-5p/MMP2, providing novel insights into the role of circRNAs in NSCLC progression.

Diminishing Cohesion of Chitosan Films in Acidic Solution by Multivalent Metal Cations.

Chitosan is a natural polymer with good biocompatibility, biodegradability, and bioactivity that has great potential for biomedical and industrial applications. Like other natural sugar-based polymers, chitosan molecules own versatile adhesion abilities to bind with various surfaces, owing to multiple functional moieties contained in the chain. To develop the promising biomaterials based on the chitosan chemistry, it is fundamentally important to figure out its adhesion mechanism under a certain condition, which leaves us numbers of open questions. In this work, we characterized the chitosan films adsorbed on a mica substrate in acidic solution and investigated the effects of multivalent salts on the cohesive behaviors of the films by means of the surface forces apparatus. The results showed that the cohesion capacities of chitosan films were reduced to around 30% of their original states after the addition of 10-7 M LaCl3 into 150 mM acetic acid, which could be partially recovered by holding the films at the contact position for a longer time. Surprisingly, the cohesion loss in the films exhibited the dependence on the properties of the metal cations including valance and concentration. The topography of the chitosan-coated surface also showed obvious aggregation in the presence of submicromolar of the salts. Here, we attributed these phenomena regarding cohesion loss to the mechanisms involved in the absorption of metal cations by the chitosan chains, which not only consumed the binding sites but also induced conformation change in the polymer network. Our findings may offer a suggestion for the production of chitosan-based materials to notice the potential impacts of ultralow concentrated salts that are usually neglected even under acidic conditions.

Development and parameter identification of a visco-hyperelastic model for the periodontal ligament.

The present study developed and implemented a new visco-hyperelastic model that is capable of predicting the time-dependent biomechanical behavior of the periodontal ligament. The constitutive model has been implemented into the finite element package ABAQUS by means of a user-defined material subroutine (UMAT). The stress response is decomposed into two constitutive parts in parallel which are a hyperelastic and a time-dependent viscoelastic stress response. In order to identify the model parameters, the indentation equation based on V-W hyperelastic model and the indentation creep model are developed. Then the parameters are determined by fitting them to the corresponding nanoindentation experimental data of the PDL. The nanoindentation experiment was simulated by finite element analysis to validate the visco-hyperelastic model. The simulated results are in good agreement with the experimental data, which demonstrates that the visco-hyperelastic model developed is able to accurately predict the time-dependent mechanical behavior of the PDL.

Structure and properties of water film adsorbed on mica surfaces.

The structure profiles and physical properties of the adsorbed water film on a mica surface under conditions with different degrees of relative humidity are investigated by a surface force apparatus. The first layer of the adsorbed water film shows ice-like properties, including a lattice constant similar with ice crystal, a high bearing capacity that can support normal pressure as high as 4 MPa, a creep behavior under the action of even a small normal load, and a character of hydrogen bond. Adjacent to the first layer of the adsorbed water film, the water molecules in the outer layer are liquid-like that can flow freely under the action of external loads. Experimental results demonstrate that the adsorbed water layer makes the mica surface change from hydrophilic to weak hydrophobic. The weak hydrophobic surface may induce the latter adsorbed water molecules to form water islands on a mica sheet.

Study of DNA adsorption on mica surfaces using a surface force apparatus.

We report our studies on the adsorption properties of double-stranded DNA molecules on mica surfaces in a confined environment using a surface force apparatus. Specifically, we studied the influence of cation species and concentrations on DNA adsorption properties. Our results indicated that divalent cations (Mg(2+) and Co(2+)) preferred to form uniform and moderately dense DNA layers on a mica substrate. By measuring the interactions between DNA-coated mica and bare mica in an aqueous solution, obvious adhesion was observed in a cobalt chloride solution, possibly due to the ion-correlation attraction between negatively charged DNA and the mica surface. Furthermore, the interaction differences that were observed with MgCl2 and CoCl2 solutions reveal that the specific adsorption behaviors of DNA molecules on a mica substrate were mediated by these two salts. Our results are helpful to elucidate the dynamics of DNA binding on a solid substrate.

Experimental observation of the ion-ion correlation effects on charge inversion and strong adhesion between mica surfaces in aqueous electrolyte solutions.

Direct force measurements between two mica surfaces in aqueous electrolyte solutions over broad ranges of LaCl3 concentrations and pH values were carried out with a surface forces apparatus. Charge inversion on mica surfaces is detected once the LaCl3 concentration reaches a critical value. With the continual increase of LaCl3 concentrations, the mica surface will be overscreened by the counterions. It is demonstrated that the two mica surfaces may experience the jump-in contact even at high LaCl3 concentrations, which is seldom seen in monovalent salt solutions. The strong adhesion cannot be attributed to the van der Waals force alone, but should include the ion-ion correlation forces. Through adjusting the pH values in LaCl3 solutions, the ion-ion correlation force can be evaluated quantitatively. These results provide important insight into the fundamental understanding in the role of ion-ion correlations in ion screening mechanism and interactions between charged objects.

A study of structure and properties of molecularly thin methanol film using the modified surface forces apparatus.

A novel approach for studying the adsorption and evaporation processes of molecularly thin methanol film by the modified surface forces apparatus (M-SFA) is reported. This method can be used precisely to measure the thickness, morphology, and mechanical properties of the film confined between two mica surfaces in a real-time manner at gas atmosphere. By observing the adsorption and evaporation processes of the methanol molecule, it is found that the first adsorbed layer of the methanol film on the mica surface behaves as a solid-like structure. The thickness of this layer is measured to be about 3.2 Å, approximately equal to the diameter of a methanol molecule. Besides, this first adsorbed layer can carry normalized loads of more than 5.6 atm due to the carrying capacity conserved by the bond of mica-OH. The outer layers of the methanol film are further adsorbed with the increase of the exposure time, which are liquid-like and can be easily eliminated out from the substrate. The present study suggests that the interacting mode between hydroxy and mica is of great potential in material science and biomedical systems.

Imaging the condensation and evaporation of molecularly thin ethanol films with surface forces apparatus.

A new method for imaging condensation and evaporation of molecularly thin ethanol films is reported. It is found that the first adsorbed layer of ethanol film on mica surface behaves as solid like structure that cannot flow freely. With the increase of exposure time, more ethanol molecules condense over the mica surface in the saturated ethanol vapor condition. The first layer of adsorbed ethanol film is about 3.8 Å thick measured from the surface forces apparatus, which is believed to be the average diameter of ethanol molecules while they are confined in between two atomically smooth mica surfaces.