Genetic disruption of ATAT1 causes RhoA downregulation through abnormal truncation of C/EBPß.

Microtubule acetylation has been shown to regulate actin filament dynamics by modulating signaling pathways that control actin organization, although the precise mechanisms remain unknown. In this study, we found that the downregulation of microtubule acetylation via the disruption ATAT1 (which encodes α-tubulin N-acetyltransferase 1) inhibited the expression of RhoA, a small GTPase involved in regulating the organization of actin filaments and the formation of stress fibers. Analysis of RHOA promoter and chromatin immunoprecipitation assays revealed that C/EBPß is a major regulator of RHOA expression. Interestingly, the majority of C/EBPß in ATAT1 knockout (KO) cells was found in the nucleus as a 27-kDa fragment (referred to as C/EBPßp27) lacking the N-terminus of C/EBPß. Overexpression of a gene encoding a C/EBPßp27-mimicking protein via an N-terminal deletion in C/EBPß led to competitive binding with wild-type C/EBPß at the C/EBPß binding site in the RHOA promoter, resulting in a significant decrease of RHOA expression. We also found that cathepsin L (CTSL), which is overexpressed in ATAT1 KO cells, is responsible for C/EBPßp27 formation in the nucleus. Treatment with a CTSL inhibitor led to the restoration of RHOA expression by downregulation of C/EBPßp27 and the invasive ability of ATAT1 KO MDA-MB-231 breast cancer cells. Collectively, our findings suggest that the downregulation of microtubule acetylation associated with ATAT1 deficiency suppresses RHOA expression by forming C/EBPßp27 in the nucleus through CTSL. We propose that CTSL and C/EBPßp27 may represent a novel therapeutic target for breast cancer treatment. [BMB Reports 2024; 57(6): 293-298].

Selective Transfer of Light-Emitting Diodes onto a Flexible Substrate via Laser Lissajous Scanning.

As the light-emitting diode (LED) size gradually decreases, it is difficult to conventionally transfer an LED onto a donor substrate. In this paper, we propose a print transfer method that selectively transfers an LED onto a UV release tape, i.e., the donor substrate, via focused laser scanning with Lissajous patterns. We implemented an optical system based on focused laser scanning to perform selective transfer; this can adjust the scanning area immediately without changing the donor substrate size according to the LED size. Because the commercialized UV release tape is utilized as a donor substrate, the adhesion between the LED and donor substrate can be constantly maintained even after repeated experiments. In this study, several LEDs were transferred to a flexible printed circuit board-arranged in a circular and square shape to demonstrate a high degree of freedom of the system-and turned on.

Comparison of long-term treatment outcomes of T2N0M0 laryngeal squamous cell carcinoma using different treatment methods.

Early [stage I and II (T2N0M0)] laryngeal cancer types are currently recommended to be treated with a single modality, consisting of definitive radiation therapy or larynx-preserving surgery. Although the treatment outcomes of stage I are good, the frequency of successful outcomes decreases with T2N0M0. Therefore, the present study investigated the treatment outcomes of different treatment methods in T2N0M0 laryngeal cancer. In total, 83 patients with previously untreated T2N0M0 laryngeal squamous cell carcinoma were enrolled. Patients were grouped by treatment method: Radiation therapy (RT; 27 patients); chemoradiotherapy (CRT; 46 patients) with cisplatin base; and surgery-based therapy (SBT; ten patients). The recurrence rates of the RT, CRT and SBT groups were 44.4, 19.6 and 50%, respectively. Moreover, the local control rates of the RT, CRT and SBT groups were 55.6, 87.0 and 80%, respectively. The CRT group had a significantly lower recurrence rate and higher local control rate compared with the RT group (P<0.05). In the survival analysis, overall and disease-specific survival rate did not differ significantly among the treatment groups. However, 3- and 5-year disease-free survival rates (DFS) of the RT group were both 55%, those of the SBT group were both 50% and those of the CRT group were both 80%. Furthermore, the DFS was significantly higher in CRT group compared with the other groups (P=0.02). Using multivariate analysis with Cox regression, it was found that the treatment method was the most important factor for DFS and had a significant impact in the CRT group. In addition, in patients with glottic cancer with anterior commissure and subglottic invasion, the CRT group had significantly improved DFS compared with the RT group, whereas there was no significant difference between the two groups in patients without subglottic invasion. According to National Cancer Institution Common Toxicity Criteria (version 5.0), more patients had toxicity in the CRT group compared with the RT group. However, in the RT and CRT groups, no patients demonstrated mortality due to toxicity, and treatment-related toxicities were manageable. Collectively, although definitive conclusions could not be established, due to the limitations of this retrospective study, the results suggest that CRT had a positive impact on the local control and DFS rates with manageable toxicity in patients with T2N0M0 laryngeal cancer.

Shwachman-Bodian-Diamond syndrome protein desensitizes breast cancer cells to apoptosis in stiff matrices by repressing the caspase 8-mediated pathway.

Certain cancer types, including breast cancer, are accompanied with stiffening of the surrounding extracellular matrix (ECM). Previous studies suggest that this stiffened matrix influences cancer cell progression, such as proliferation and invasion, both biochemically and mechanically. However, the contribution of ECM stiffness to cellular response to diverse stresses, which most cancer cells are exposed to, has not been elucidated. In this study, we demonstrate that expression of the Shwachman-Bodian-Diamond syndrome protein (SDBS) in a stiff matrix protects cells from apoptosis induced by environmental stress, including anticancer drugs. Cells cultured on stiff matrices were less apoptotic process induced by serum depletion than those cultured on the soft matrix. Interestingly, knockdown (KD) of SDBS among the apoptosis-related genes significantly increased apoptosis induced by serum depletion in cells cultured in a stiff matrix. Apoptosis of SDBS KD cells in a stiff matrix was significantly inhibited by the caspase 8 inhibitor, indicating that activation of the caspase 8 pathway by SDBS KD is critical for cancer cell apoptosis in stiff matrices. Additionally, we also found that downregulation of SDBS also effectively increased cell death induced by anticancer drugs, including paclitaxel, cisplatin, and eribulin. Taken together, our findings suggest that inhibition of SDBS enhances effective chemotherapy of malignant breast cancer cells in stiff ECM environments.

Downregulation of SPIN90 promotes fibroblast activation via periostin-FAK-ROCK signaling module.

Alterations in mechanical properties in the extracellular matrix are modulated by myofibroblasts and are required for progressive fibrotic diseases. Recently, we reported that fibroblasts depleted of SPIN90 showed enhanced differentiation into myofibroblasts via increased acetylation of microtubules in the soft matrix; the mechanisms of the underlying signaling network, however, remain unclear. In this study, we determine the effect of depletion of SPIN90 on FAK/ROCK signaling modules. Transcriptome analysis of Spin90 KO mouse embryonic fibroblasts (MEF) and fibroblasts activated by TGF-ß revealed that Postn is the most significantly upregulated gene. Knockdown of Postn by small interfering RNA suppressed cell adhesion and myofibroblastic differentiation and downregulated FAK activity in Spin90 KO MEF. Our results indicate that SPIN90 depletion activates FAK/ROCK signaling, induced by Postn expression, which is critical for myofibroblastic differentiation on soft matrices mimicking the mechanical environment of a normal tissue.

Spindle pole body component 25 homolog expressed by ECM stiffening is required for lung cancer cell proliferation.

Accumulating evidence has shown that matrix stiffening in cancer tissue by the deposition of extracellular matrix (ECM) is closely related with severe tumor progression. However, much less is known about the genes affected by matrix stiffness and its signaling for cancer progression. In the current research, we investigated the differential gene expression of a non-small lung adenocarcinoma cell line, H1299, cultured under the conditions of soft (∼0.5 kPa) and stiff (∼40 kPa) matrices, mimicking the mechanical environments of normal and cancerous tissues, respectively. For integrated transcriptome analysis, the genes identified by ECM stiffening were compared with 8248 genes retrieved from The Cancer Genome Atlas Lung Adenocarcinoma (TCGA). In stiff matrix, 29 genes were significantly upregulated, while 75 genes were downregulated. The screening of hazard ratios for these genes using the Kaplan-Meier Plotter identified 8 genes most closely associated with cancer progression under the condition of matrix stiffening. Among these genes, spindle pole body component 25 homolog (SPC25) was one of the most up-regulated genes in stiff matrix and tumor tissue. Knockdown of SPC25 in H1299 cells using shRNA significantly inhibited cell proliferation with downregulation of the expression of checkpoint protein, Cyclin B1, under the condition of stiff matrix whereas the proliferation rate in soft matrix was not affected by SPC25 silencing. Thus, our findings provide novel key molecules for studying the relationship of extracellular matrix stiffening and cancer progression.

Ultrafast structural evolution and formation of linear carbon chains in single-walled carbon nanotube networks by femtosecond laser irradiation.

Inter-allotropic structural transformation of sp2 structured nanocarbon is a topic of fundamental and technological interest in scalable nanomanufacturing. Such modifications usually require extremely high temperature or high-energy irradiation, and are usually a destructive and time-consuming process. Here, we demonstrate a method for engineering a molecular structure of single-walled carbon nanotubes (SWNTs) and their network properties by femtosecond laser irradiation. This method allows effective coalescence between SWNTs, transforming them into other allotropic nanocarbon structures (double-walled, triple-walled and multi-walled nanotubes) with the formation of linear carbon chains. The nanocarbon network created by this laser-induced transformation process shows extraordinarily strong coalescence induced mode in Raman spectra and two-times enhanced electrical conductivity. This work suggests a powerful method for engineering sp2 carbon allotropes and their junctions, which provides possibilities for next generation materials with structural hybridization at the atomic scale.

Effect of laser-dimpled titanium surfaces on attachment of epithelial-like cells and fibroblasts.

PURPOSE: The objective of this study was to conduct an in vitro comparative evaluation of polished and laserdimpled titanium (Ti) surfaces to determine whether either surface has an advantage in promoting the attachment of epithelial-like cells and fibroblast to Ti. MATERIALS AND METHODS: Forty-eight coin-shaped samples of commercially pure, grade 4 Ti plates were used in this study. These discs were cleaned to a surface roughness (Ra: roughness centerline average) of 180 nm by polishing and were divided into three groups: SM (n=16) had no dimples and served as the control, SM15 (n=16) had 5-µm dimples at 10-µm intervals, and SM30 (n=16) had 5-µm dimples at 25-µm intervals in a 2 × 4 mm(2) area at the center of the disc. Human gingival squamous cell carcinoma cells (YD-38) and human lung fibroblasts (MRC-5) were cultured and used in cell proliferation assays, adhesion assays, immunofluorescent staining of adhesion proteins, and morphological analysis by SEM. The data were analyzed statistically to determine the significance of differences. RESULTS: The adhesion strength of epithelial cells was higher on Ti surfaces with 5-µm laser dimples than on polished Ti surfaces, while the adhesion of fibroblasts was not significantly changed by laser treatment of implant surfaces. However, epithelial cells and fibroblasts around the laser dimples appeared larger and showed increased expression of adhesion proteins. CONCLUSION: These findings demonstrate that laser dimpling may contribute to improving the periimplant soft tissue barrier. This study provided helpful information for developing the transmucosal surface of the abutment.