Theaflavin -3,3'-digallate/ethanol: a novel cross-linker for stabilizing dentin collagen.

Objectives: To study the ability of theaflavin-3,3'-digallate (TF3)/ethanol solution to crosslink demineralized dentin collagen, resist collagenase digestion, and explore the potential mechanism. Methods: Fully demineralized dentin blocks were prepared using human third molars that were caries-free. Then, these blocks were randomly allocated into 14 separate groups (n = 6), namely, control, ethanol, 5% glutaraldehyde (GA), 12.5, 25, 50, and 100 mg/ml TF3/ethanol solution groups. Each group was further divided into two subgroups based on crosslinking time: 30 and 60 s. The efficacy and mechanism of TF3's interaction with dentin type I collagen were predicted through molecular docking. The cross-linking, anti-enzymatic degradation, and biomechanical properties were studied by weight loss, hydroxyproline release, scanning/transmission electron microscopy (SEM/TEM), in situ zymography, surface hardness, thermogravimetric analysis, and swelling ratio. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy were utilized to explore its mechanisms. Statistical analysis was performed using one and two-way analysis of variance and Tukey's test. Results: TF3/ethanol solution could effectively crosslink demineralized dentin collagen and improve its resistance to collagenase digestion and biomechanical properties (p < 0.05), showing concentration and time dependence. The effect of 25 and 50 mg/ml TF3/ethanol solution was similar to that of 5% GA, whereas the 100 mg/mL TF3/ethanol solution exhibited better performance (p < 0.05). TF3 and dentin type I collagen are mainly cross-linked by hydrogen bonds, and there may be covalent and hydrophobic interactions. Conclusion: TF3 has the capability to efficiently cross-link demineralized dentin collagen, enhancing its resistance to collagenase enzymatic hydrolysis and biomechanical properties within clinically acceptable timeframes (30 s/60 s). Additionally, it exhibits promise in enhancing the longevity of dentin adhesion.

Nucleus-targeting DNase I self-assembly delivery system guided by pirarubicin for programmed multi-drugs release and combined anticancer therapy.

The cell nucleus serves as the pivotal command center of living cells, and delivering therapeutic agents directly into the nucleus can result in highly efficient anti-tumor eradication of cancer cells. However, nucleus-targeting drug delivery is very difficult due to the presence of numerous biological barriers. Here, three antitumor drugs (DNase I, ICG: indocyanine green, and THP: pirarubicin) were sequentially triggered protein self-assembly to produce a nucleus-targeting and programmed responsive multi-drugs delivery system (DIT). DIT consisted of uniform spherical particles with a size of 282 ± 7.7 nm. The acidic microenvironment of tumors and near-infrared light could successively trigger DIT for the programmed release of three drugs, enabling targeted delivery to the tumor. THP served as a nucleus-guiding molecule and a chemotherapy drug. Through THP-guided DIT, DNase I was successfully delivered to the nucleus of tumor cells and killed them by degrading their DNA. Tumor acidic microenvironment had the ability to induce DIT, leading to the aggregation of sufficient ICG in the tumor tissues. This provided an opportunity for the photothermal therapy of ICG. Hence, three drugs were cleverly combined using a simple method to achieve multi-drugs targeted delivery and highly effective combined anticancer therapy.

Identification of a basement membrane gene signature for predicting prognosis and estimating the tumor immune microenvironment in prostate cancer.

Basement membrane plays an important role in tumor invasion and metastasis, which is closely related to prognosis. However, the prognostic value and biology of basement membrane genes (BMGs) in prostate cancer (PCa) remain unknown. In the TCGA training set, we used differentially expressed gene analysis, protein-protein interaction networks, univariate and multivariate Cox regression, and least absolute shrinkage and selection operator regression to construct a basement membrane-related risk model (BMRM) and validated its effectiveness in the MSKCC validation set. Furthermore, the accurate nomogram was constructed to improve clinical applicability. Patients with PCa were divided into high-risk and low-risk groups according to the optimal cut-off value of the basement membrane-related risk score (BMRS). It was found that BMRS was significantly associated with RFS, T-stage, Gleason score, and tumor microenvironmental characteristics in PCa patients. Further analysis showed that the model grouping was closely related to tumor immune microenvironment characteristics, immune checkpoint inhibitors, and chemotherapeutic drug sensitivity. In this study, we developed a new BMGs-based prognostic model to determine the prognostic value of BMGs in PCa. Finally, we confirmed that THBS2, a key gene in BMRM, may be an important link in the occurrence and progression of PCa. This study provides a novel perspective to assess the prognosis of PCa patients and provides clues for the selection of future personalized treatment regimens.

Identification and partial characterization of new cell density-dependent nucleocytoplasmic shuttling proteins and open chromatin.

The contact inhibition of proliferation (CIP) denotes the cell density-dependent inhibition of growth, and the loss of CIP represents a hallmark of cancer. However, the mechanism by which CIP regulates gene expression remains poorly understood. Chromatin is a highly complex structure consisting of DNA, histones, and trans-acting factors (TAFs). The binding of TAF proteins to specific chromosomal loci regulates gene expression. Therefore, profiling chromatin is crucial for gaining insight into the gene expression mechanism of CIP. In this study, using modified proteomics of TAFs bound to DNA, we identified a protein that shuttles between the nucleus and cytosol in a cell density-dependent manner. We identified TIPARP, PTGES3, CBFB, and SMAD4 as cell density-dependent nucleocytoplasmic shuttling proteins. In low-density cells, these proteins predominantly reside in the nucleus; however, upon reaching high density, they relocate to the cytosol. Given their established roles in gene regulation, our findings propose their involvement as CIP-dependent TAFs. We also identified and characterized potential open chromatin regions sensitive to changes in cell density. These findings provide insights into the modulation of chromatin structure by CIP.

Prolonged Linear Amplification of qPCR for the Correction of Amplification Variation and the Absolute Quantification without Standard Curves.

The variable amplification efficiency of each thermal cycle of qPCR obeys the Poisson distribution, and the qPCR system dynamically changes, so there must be a detection error in its quantitative analysis. Here, more than 20 cycles of the linear amplification of qPCR can be produced as the BSA hydrogel is introduced to achieve the controlled release of Taq DNA polymerase. There is a significant negative correlation between the slope of linear amplification and Ct values (r = -0.9455), and it is well evident that the slope can reflect the amplification efficiency and a linear positive correlation exists between them. Through the change in the concentration of primers in the qPCR system, an exponential equation between Ct values and the slopes can be fitted (R2 = 0.9995). The slopes and Ct values of each qPCR system can be corrected by using this equation to guarantee that there will be significant consistency in their amplification efficiency because the degree of linear fitting (R2) between Ct values and the logarithm of their corresponding concentration of the DNA template increased significantly. By this time, the accurate amplification efficiency can be calculated in a known multiple of two initial concentrations of DNA templates. With the aid of the relationship between the known primer concentration and the fluorescence intensity at the end of PCR (End RFU), the initial concentrations of DNA templates can be reversely calculated in the absence of standard curves.

SETD4 inhibits prostate cancer development by promoting H3K27me3-mediated NUPR1 transcriptional repression and cell cycle arrest.

The suppressor of variegation enhancer of zeste-trithorax (SET) domain methyltransferases have been reported to function as key regulators in multiple tumor types by catalyzing histone lysine methylation. Nevertheless, our understanding on the role of these lysine methyltransferases, including SETD4, in prostate cancer (PCa) remains limited. Hence, the specific role of SETD4 in PCa was investigated in this study. The expression of SETD4 in PCa cells and tissue samples was downregulated in PCa cells and tissue specimens, and decreased SETD4 expression led to inferior clinicopathological characteristics in patients with PCa. knockdown of SETD4 facilitated the proliferation of PCa cells and accelerated cell cycle progression. Mechanistically, SETD4 repressed NUPR1 transcription by methylating H3K27 to generate H3K27me3, subsequently inactivated Akt pathway and impeded the tumorigenesis of PCa. Our results highlight that SETD4 prevents the development of PCa by catalyzing the methylation of H3K27 and suppressing NUPR1 transcription, subsequently inactivating the Akt signaling pathway. The findings suggest the potential application of SETD4 in PCa prognosis and therapeutics.

UBE2A/B is the trans-acting factor mediating mechanotransduction and contact inhibition.

Mechanotransduction and contact inhibition (CI) control gene expression to regulate proliferation, differentiation, and even tumorigenesis of cells. However, their downstream trans-acting factors (TAFs) are not well known due to a lack of a high-throughput method to quantitatively detect them. Here, we developed a method to identify TAFs on the cis-acting sequences that reside in open chromatin or DNaseI-hypersensitive sites (DHSs) and to detect nucleocytoplasmic shuttling TAFs using computational and experimental screening. The DHS-proteomics revealed over 1000 potential mechanosensing TAFs and UBE2A/B (Ubiquitin-conjugating enzyme E2 A) was experimentally identified as a force- and CI-dependent nucleocytoplasmic shuttling TAF. We found that translocation of YAP/TAZ and UBE2A/B are distinctively regulated by inhibition of myosin contraction, actin-polymerization, and CI depending on cell types. Next-generation sequence analysis revealed many downstream genes including YAP are transcriptionally regulated by ubiquitination of histone by UBE2A/B. Our results suggested a YAP-independent mechanotransduction and CI pathway mediated by UBE2A/B.

Selective Photochromic Response to Low-Dose X-ray Radiation Detection in One-Dimensional Cadmium-Viologen Complexes.

Photochromic viologen-based materials have emerged as one of the most promising candidates for the development of X-ray light detection applications, including medical diagnosis and treatment, environmental radiation inspection, and industrial crack detection. However, the design and construction of low-dose X-ray-sensitive complexes remains an immense challenge, especially for the in-depth dissection of their response mechanisms. Herein, by using N,N'-4,4'-bipyridiniodipropionate (CV) as functional sensitive structural units and cadmium as heavy atoms, two cadmium-viologen complexes with one-dimensional chained structures, namely, [Cd2Cl4(CV)(H2O)2]n (1) and [CdBr2(CV)]n (2), have been constructed, which exhibit a remarkable and selective photochromic response to low-dose X-ray radiation detection. Compound 1 is visually sensitive to both X-ray and UV light due to the more accessible photoinduced electron transfer (ET) pathways, while compound 2 only shows a slight color-changing process in response to UV light, in conformity with UV-vis absorbance analyses and kinetic studies. Surprisingly, compound 2 has longer ET pathways than 1, but not in response to high-energy X-ray light, seeming to contradict the previous phenomena. On further analysis, the key point in achieving X-ray-sensitive behavior should be a good balance among the electron donor-acceptor distance, intermolecular interaction, and X-ray absorbing capacity, as verified by density functional theory (DFT) and X-ray absorption strength calculations, X-ray photoelectron spectra, electron paramagnetic resonance measurements, and independent gradient model analysis. In particular, compound 1 is unprecedentedly sensitive to soft X-ray radiation, accompanied by an X-ray detection limit of as low as 2.91 Gy. These findings push forward the further development of low-dose X-ray sensing materials.

Programmed-stimuli responsive carrier-free multidrug delivery system for highly efficient trimodal combination therapy.

Programmed response, carrier-free, and multimodal therapy drug delivery systems (DDS) are promising solutions to multidirectional cytotoxic effects, inefficient antitumor, and severe side effects for cancer therapy. Here, three widely used clinical drugs, interferon α1b (IFNα1b), indocyanine green (ICG), and doxorubicin (DOX), were prepared into carrier-free DDS IFNα1b-ICG-DOX (IID) by a simple one-step method without additional any reagents. IID can achieve smart and programmed DDS by combining low pH and near-infrared (NIR) light stimuli-responsive controlled release. In pH = 7.4 environments, our IID is about 380 nm in size with negative charge rounded particles; while they enter into the acid environment (pH < 7), hydrogen ions (H+) trigger DOX release, their size becomes larger and the surface charge turns positive. These larger particles are rapidly disintegrated after exposure to NIR light and then the remaining DOX, IFNα1b, and ICG are released. In vivo, the IID with larger size and positive charge resulting from low pH is is easy to accumulate in tumor tissue. Tumors can be exposed to NIR light when needed to control the release of these three drugs. Hence, DOX, ICG, and IFNα1b can be enriched in the tumor to the high efficiency of combined chemotherapy, photothermal therapy, and immunotherapy.

An acid-base responsive AuI integrated contrast agent for Optical/CT double-modal imaging to detect pH change of digestive tract.

The detection of pH change in the gastrointestinal tract (GIT) is invasive and the intestinal pH detection is even harder. Here, we develop an AuI integrated contrast agent (Au NCs@DA) for noninvasive GIT imaging to detect pH change. This agent is composed of gold nanoclusters (Au NCs) and diatrizoic acid (DA) and is extremely sensitive to the acid-base response. Au NCs@DA about 400 nm in size can be stable in acid solution and make the fluorescence intensity of Au NCs to drop significantly. After entering a neutral environment, Au NCs@DA can rapidly form sediment, and then its CT value and fluorescence increase. Alkaline pH can trigger the release of DA from Au NCs@DA to make its fluorescence intensity to recover. As entering GIT, Au NCs@DA can successively outline their anatomy for optical/CT double-modal imaging under gastrointestinal motility. The variations of the fluorescence and CT images triggered by different pH are also recorded to analyze the pH change of GIT. Furthermore, the clearance rate of stable Au NCs@DA in acid pH increases, which also can assist to evaluate pH value. Therefore, Au NCs@DA can definitely be an excellent candidate for the noninvasive detection of pH change in GIT through optical/CT double-modal imaging.

Preparation of chitosan-sodium alginate films through layer-by-layer assembly and ferulic acid crosslinking: Film properties, characterization, and formation mechanism.

Chitosan-alginate films were prepared through layer-by-layer assembly combined with ferulic acid crosslinking. Their mechanical properties, opacity, and hydrophobicity were compared to films prepared by direct mixing, crosslinking alone, and LBL assembly alone. Thermogravimetric analysis, X-ray diffraction, scanning electron microscopy and Fourier-transform infrared spectroscopy were used to characterize the films and analyze their formation mechanism. The results indicated that the layer-by-layer assembly and ferulic acid crosslinking combination increased the tensile strength and light-blocking ability of the films. In addition, the films had a lower water vapor transmission rate, swelling degree, and water solubility, as well as higher hydrophobicity. Scanning electron microscopy showed a good compatibility between the film components of the film prepared by the combination technique. The structural characterization results revealed some strong interactions among the amino, carboxyl, and hydroxyl groups of the ferulic acid, chitosan, and sodium alginate in the film. The driving force for film formation was the generation of non-covalent bonds among the film components rather than covalent bonds.