Cancer SLC6A6-mediated taurine uptake transactivates immune checkpoint genes and induces exhaustion in CD8+ T cells.

Taurine is used to bolster immunity, but its effects on antitumor immunity are unclear. Here, we report that cancer-related taurine consumption causes T cell exhaustion and tumor progression. The taurine transporter SLC6A6 is correlated with aggressiveness and poor outcomes in multiple cancers. SLC6A6-mediated taurine uptake promotes the malignant behaviors of tumor cells but also increases the survival and effector function of CD8+ T cells. Tumor cells outcompete CD8+ T cells for taurine by overexpressing SLC6A6, which induces T cell death and malfunction, thereby fueling tumor progression. Mechanistically, taurine deficiency in CD8+ T cells increases ER stress, promoting ATF4 transcription in a PERK-JAK1-STAT3 signaling-dependent manner. Increased ATF4 transactivates multiple immune checkpoint genes and induces T cell exhaustion. In gastric cancer, we identify a chemotherapy-induced SP1-SLC6A6 regulatory axis. Our findings suggest that tumoral-SLC6A6-mediated taurine deficiency promotes immune evasion and that taurine supplementation reinvigorates exhausted CD8+ T cells and increases the efficacy of cancer therapies.

A novel lncRNA associated with the prognosis of patients with colorectal cancer resists apoptosis through the LYN/BCL-2 pathway.

PURPOSE: We found a novel lncRNA named lncAC138150.2 related to the overall survival and staging of patients with colorectal cancer (CRC) by bioinformatic analysis using data from the Cancer Genome Atlas (TCGA), and the study aimed to elucidate the function of lncAC138150.2 and underlying mechanisms. METHODS: Target molecules were knocked down by transfection with antisense oligonucleotides (ASOs), siRNAs, or lentiviruses and overexpressed by transfection with plasmids. The function of lncAC138150.2 was determined using histological, cytological, and molecular biology methods. The underlying mechanism of lncAC138150.2 function was investigated using RNA-seq, bioinformatics analysis, and molecular biology methods. RESULTS: The expression of lncAC138150.2 was increased in colorectal tissues compared with paired normal tissues. The lncAC138150.2 knockdown increased apoptosis but did not change the cell proliferation, cell cycle distribution, or cell migration ability of CRC cells, while lncAC138150.2 overexpression decreased CRC apoptosis. lncAC138150.2 was mainly located in the cell nucleus, and each lncAC138150.2 transcript knockdown increased CRC apoptosis. BCL-2 pathway was significantly altered in apoptosis induced by lncAC138150.2 knockdown, which was alleviated by BAX knockdown. The expression of LYN was significantly decreased with lncAC138150.2 knockdown, LYN knockdown increased CRC apoptosis, and its overexpression completely alleviated CRC apoptosis induced by lncAC138150.2 knockdown. CONCLUSION: lncAC138150.2 significantly inhibited CRC apoptosis and affected the prognosis of patients with CRC, through the LYN/BCL-2 pathway.

Single-frequency fiber lasers based on metal thiophosphites with sub-kHz linewidths.

Metal thiophosphites (CrPX4) (X = S and Se), emerging layered metal chalcogenophosphate materials, have found extensive utility in the fields of advanced electronic devices, magnetic technologies, and electrochemical systems. However, their applications in single-frequency fiber lasers have been relatively limited. Here, liquid phase exfoliation technology is used to exfoliate the CrPX4 into few-layered samples. Subsequently, we explored the application of CrPX4-based saturable absorbers (CrPX4-SA) by precisely depositing CrPX4 nanosheets onto the surface of D-shaped fibers. This led to the successful creation of two stable single-frequency fiber lasers (SFFLs) based on CrPS4 and CrPSe4 with center wavelengths of 1550.068 nm and 1550.092 nm, respectively. The linewidth of CrPSe4 was tested and determined to be roughly 375 Hz, which is the narrowest ever value attained for an SFFL based on its structure, and its signal-to-noise ratio (SNR) was 74.17 dB. The maximum output power of each oscillator was 0.796 mW and 0.963 mW, and their corresponding power fluctuations were 2.5% and 1.4%, respectively.

Deposition of FeOOH Layer on Ultrathin Hematite Nanoflakes to Promote Photoelectrochemical Water Splitting.

Hematite is one of the most promising photoanode materials for the study of photoelectrochemical (PEC) water splitting because of its ideal bandgap with sufficient visible light absorption and stability in alkaline electrolytes. However, owing to the intrinsically high electron-hole recombination, the PEC performance of hematite is still far below that expected. The efficient charge separation can be achieved via growth of FeOOH on hematite photoanode. In this study, hematite nanostructures were successfully grown on the surface of iron foil by the simple immersion deposition method and thermal oxidation treatment. Furthermore, cocatalyst FeOOH was successfully added to the hematite nanostructure surface to improve charge separation and charge transfer, and thus promote the photoelectrochemical water splitting. By utilizing the FeOOH overlayer as a cocatalyst, the photocurrent density of hematite exhibited a substantial 86% increase under 1.5 VRHE, while the onset potential showed an apparent shift towards the cathodic direction. This can be ascribed to the high reaction area for the nanostructured morphology and high electrocatalytic activity of FeOOH that enhanced the amount of photogenerated holes and accelerated the kinetics of water splitting.

Mitochondria-targeted photodynamic therapy triggers GSDME-mediated pyroptosis and sensitizes anti-PD-1 therapy in colorectal cancer.

BACKGROUND: The effectiveness of immune checkpoint inhibitors in colorectal cancer (CRC) is limited due to the low tumor neoantigen load and low immune infiltration in most microsatellite-stable (MSS) tumors. This study aimed to develop a mitochondria-targeted photodynamic therapy (PDT) approach to provoke host antitumor immunity of MSS-CRC and elucidate the underlying molecular mechanisms. METHODS: The role and mechanism of mitochondria-targeted PDT in inhibiting CRC progression and inducing pyroptosis were evaluated both in vitro and in vivo. The immune effects of PDT sensitization on PD-1 blockade were also assessed in CT26 and 4T1 tumor-bearing mouse models. RESULTS: Here, we report that PDT using IR700DX-6T, a photosensitizer targeting the mitochondrial translocation protein, may trigger an antitumor immune response initiated by pyroptosis in CRC. Mechanistically, IR700DX-6T-PDT produced reactive oxygen species on light irradiation and promoted downstream p38 phosphorylation and active caspase3 (CASP3)-mediated cleavage of gasdermin E (GSDME), subsequently inducing pyroptosis. Furthermore, IR700DX-6T-PDT enhanced the sensitivity of MSS-CRC cells to PD-1 blockade. Decitabine, a demethylation drug used to treat hematologic neoplasms, disrupted the abnormal methylation pattern of GSDME in tumor cells, enhanced the efficacy of IR700DX-6T-PDT, and elicited a potent antitumor immune response in combination with PD-1 blockade and IR700DX-6T-PDT. CONCLUSION: Our work provides clear a understanding of immunogenic cell death triggered by mitochondria-targeted PDT, offering a new approach for enhancing the efficacy of PD-1 blockade in CRC.

Determining the Young's Modulus of the Bacterial Cell Envelope.

Bacteria experience substantial physical forces in their natural environment, including forces caused by osmotic pressure, growth in constrained spaces, and fluid shear. The cell envelope is the primary load-carrying structure of bacteria, but the mechanical properties of the cell envelope are poorly understood; reports of Young's modulus of the cell envelope of Escherichia coli range from 2 to 18 MPa. We developed a microfluidic system to apply mechanical loads to hundreds of bacteria at once and demonstrated the utility of the approach for evaluating whole-cell stiffness. Here, we extend this technique to determine Young's modulus of the cell envelope of E. coli and of the pathogens Vibrio cholerae and Staphylococcus aureus. An optimization-based inverse finite element analysis was used to determine the cell envelope Young's modulus from observed deformations. The Young's modulus values of the cell envelope were 2.06 ± 0.04 MPa for E. coli, 0.84 ± 0.02 MPa for E. coli treated with a chemical (A22) known to reduce cell stiffness, 0.12 ± 0.03 MPa for V. cholerae, and 1.52 ± 0.06 MPa for S. aureus (mean ± SD). The microfluidic approach allows examination of hundreds of cells at once and is readily applied to Gram-negative and Gram-positive organisms as well as rod-shaped and cocci cells, allowing further examination of the structural causes behind differences in cell envelope Young's modulus among bacterial species and strains.

DNA damage response-related immune activation signature predicts the response to immune checkpoint inhibitors: from gastrointestinal cancer analysis to pan-cancer validation.

OBJECTIVE: DNA damage response (DDR) deficiency has emerged as a prominent determinant of tumor immunogenicity. This study aimed to construct a DDR-related immune activation (DRIA) signature and evaluate the predictive accuracy of the DRIA signature for response to immune checkpoint inhibitor (ICI) therapy in gastrointestinal (GI) cancer. METHODS: A DRIA signature was established based on two previously reported DNA damage immune response assays. Clinical and gene expression data from two published GI cancer cohorts were used to assess and validate the association between the DRIA score and response to ICI therapy. The predictive accuracy of the DRIA score was validated based on one ICI-treated melanoma and three pan-cancer published cohorts. RESULTS: The DRIA signature includes three genes (CXCL10, IDO1, and IFI44L). In the discovery cancer cohort, DRIA-high patients with gastric cancer achieved a higher response rate to ICI therapy than DRIA-low patients (81.8% vs. 8.8%; P < 0.001), and the predictive accuracy of the DRIA score [area under the receiver operating characteristic curve (AUC) = 0.845] was superior to the predictive accuracy of PD-L1 expression, tumor mutational burden, microsatellite instability, and Epstein-Barr virus status. The validation cohort demonstrated that the DRIA score identified responders with microsatellite-stable colorectal and pancreatic adenocarcinoma who received dual PD-1 and CTLA-4 blockade with radiation therapy. Furthermore, the predictive performance of the DRIA score was shown to be robust through an extended validation in melanoma, urothelial cancer, and pan-cancer. CONCLUSIONS: The DRIA signature has superior and robust predictive accuracy for the efficacy of ICI therapy in GI cancer and pan-cancer, indicating that the DRIA signature may serve as a powerful biomarker for guiding ICI therapy decisions.