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Purpose: Olaparib, an inhibitor of poly-(adenosine diphosphate-ribose) polymerase (PARP), has been shown to have anticancer benefits in patients with pancreatic cancer who have a germline mutation in BRCA1/2. However, resistance acquired on long-term exposure to olaparib significantly impedes clinical efficacy. Methods: In this study, the chromatin accessibility and differentially expressed transcripts of parental and olaparib-resistant pancreatic cancer cell lines were assessed using the Assay for Transposase Accessible Chromatin with sequencing (ATAC-seq) and mRNA-seq. Detection of downstream genes regulated by transcription factors using ChIP (Chromatin immunoprecipitation assay). Results: According to pathway enrichment analysis, differentially expressed genes in olaparib-resistant cells were remarkably enriched in the NF-κB signaling pathway. With ATAC-seq, we identified chromatin regions with higher accessibility in olaparib-resistant cells and predicted a series of important transcription factors. Among them, activating transcription factor 3 (ATF3) was significantly highly expressed. Functional experiments verified that inhibition of ATF3 suppressed the NF-κB pathway significantly and restored olaparib sensitivity in olaparib-resistant cells. Conclusion: Experiments in vitro and in vivo indicate ATF3 enhances olaparib resistance through the NF-κB signaling pathway, suggesting that ATF3 could be employed as an olaparib sensitivity and prognostic indicator in patients with pancreatic cancer. [ABSTRACT FROM AUTHOR]

Pancreatic cancer (PCa) is one of the most fatal human malignancies. The enhanced infiltration of stromal tissue into the PCa tumor microenvironment limits the identification of key tumor‐specific transcription factors and epigenomic abnormalities in malignant epithelial cells. Integrated transcriptome and epigenetic multiomics analyses of the paired PCa organoids indicate that the basic helix‐loop‐helix transcription factor 40 (BHLHE40) is significantly upregulated in tumor samples. Increased chromatin accessibility at the promoter region and enhanced mTOR pathway activity contribute to the elevated expression of BHLHE40. Integrated analysis of chromatin immunoprecipitation‐seq, RNA‐seq, and high‐throughput chromosome conformation capture data, together with chromosome conformation capture assays, indicate that BHLHE40 not only regulates sterol regulatory element‐binding factor 1 (SREBF1) transcription as a classic transcription factor but also links the enhancer and promoter regions of SREBF1. It is found that the BHLHE40‐SREBF1‐stearoyl‐CoA desaturase axis protects PCa cells from ferroptosis, resulting in the reduced accumulation of lipid peroxidation. Moreover, fatostatin, an SREBF1 inhibitor, significantly suppresses the growth of PCa tumors with high expressions of BHLHE40. This study highlights the important roles of BHLHE40‐mediated lipid peroxidation in inducing ferroptosis in PCa cells and provides a novel mechanism underlying SREBF1 overexpression in PCa. [ABSTRACT FROM AUTHOR]

Submarine garbage is constantly destroying the marine ecological environment and polluting the ocean. It is critical to use detection methods to quickly locate and identify submarine garbage. The background of submarine garbage images is much more complex than that of natural scene images, with object deformation and missing contours putting higher demands on the detection network. To solve the problem of low accuracy under complex backgrounds, full stage networks with auxiliary focal loss and multi-attention module are proposed for submarine garbage object detection based on YOLO. To maximize the gradient combination, a hierarchical fusion feature mechanism and a segmentation and merging strategy are used in this paper to optimize the difference in gradient combination to obtain full-stage features. Then the criss-cross attention module is used to precisely extract multi-scale features of small object dense regions while removing noise information from complex backgrounds. Finally, the auxiliary focal loss function addresses the issue of unbalanced positive and negative samples, focusing on the learning of difficult samples while improving overall detection precision. Based on comparative experiments and ablation experiments, the FSA networks achieved state-of-the-art performance, and is applicable to the real-time object detection of submarine garbage in complex backgrounds. [ABSTRACT FROM AUTHOR]

The extensively activated Notch signaling pathway in pancreatic cancer cells is important in carcinogenesis, chemoresistance, and recurrence. Targeting this pathway is a promising therapeutic strategy for pancreatic cancer; however, few successful approaches have been reported, and currently used molecular inhibitors of this pathway exhibit limited clinical benefits. In this study, we identified a previously uncharacterized microprotein, Notch1 degradation-associated regulatory polypeptide (N1DARP), encoded by LINC00261. N1DARP knockout accelerated tumor progression and enhanced stem cell properties in pancreatic cancer organoids and LSL-Kras, LSL-Trp53, and Pdx1-Cre (KPC) mice. Mechanistically, N1DARP suppressed canonical and non-canonical Notch1 pathways by competitively disrupting the interaction between N1ICD and ubiquitin-specific peptidase 10 (USP10), thereby promoting K11- and K48-linked polyubiquitination of N1ICD. To evaluate the therapeutic potential of N1DARP, we designed a cell-penetrating stapled peptide, SAH-mAH2-5, with a helical structure similar to that of N1DARP that confers remarkable physicochemical stability. SAH-mAH2-5 interacted with and promoted the proteasome-mediated degradation of N1ICD. SAH-mAH2-5 injection provided substantial therapeutic benefits with limited off-target and systemic adverse effects in Notch1-activated pancreatic cancer models. Taken together, these findings confirm that N1DARP acts as a tumor suppressor and chemosensitizer by regulating USP10-Notch1 oncogenic signaling, and suggest a promising therapeutic strategy targeting the N1DARP–N1ICD interaction in Notch1-activated pancreatic cancer. [ABSTRACT FROM AUTHOR]

Neuropathy is a feature more frequently observed in pancreatic ductal adenocarcinoma (PDAC) than other tumors. Schwann cells, the most prevalent cell type in peripheral nerves, migrate toward tumor cells and associate with poor prognosis in PDAC. To unveil the effects of Schwann cells on the neuro-stroma niche, here we perform single-cell RNA-sequencing and microarray-based spatial transcriptome analysis of PDAC tissues. Results suggest that Schwann cells may drive tumor cells and cancer-associated fibroblasts (CAFs) to more malignant subtypes: basal-like and inflammatory CAFs (iCAFs), respectively. Moreover, in vitro and in vivo assays demonstrate that Schwann cells enhance the proliferation and migration of PDAC cells via Midkine signaling and promote the switch of CAFs to iCAFs via interleukin-1α. Culture of tumor cells and CAFs with Schwann cells conditioned medium accelerates PDAC progression. Thus, we reveal that Schwann cells induce malignant subtypes of tumor cells and CAFs in the PDAC milieu. The effects of Schwann cells on the neuro-stroma niche in pancreatic ductal adenocarcinoma (PDAC) remain to be explored. Here, single-cell RNA-sequencing and spatial transcriptome analysis of PDAC tissues reveal that Schwann cells induce malignant subtypes of tumour cells and cancer associated fibroblasts. [ABSTRACT FROM AUTHOR]

Background: LncRNA-PACERR plays critical role in the polarization of tissue-associated macrophages (TAMs). In this study, we found the function and molecular mechanism of PACERR in TAMs to regulate pancreatic ductal adenocarcinoma (PDAC) progression. Methods: We used qPCR to analyse the expression of PACERR in TAMs and M1-tissue-resident macrophages (M1-NTRMs) which were isolated from 46 PDAC tissues. The function of PACERR on macrophages polarization and PDAC proliferation, migration and invasion were confirmed through in vivo and in vitro assays. The molecular mechanism of PACERR was discussed via fluorescence in situ hybridization (FISH), RNA pull-down, ChIP-qPCR, RIP-qPCR and luciferase assays. Results: LncRNA-PACERR was high expression in TAMs and associated with poor prognosis in PDAC patients. Our finding validated that LncRNA-PACERR increased the number of M2-polarized cells and facilized cell proliferation, invasion and migration in vitro and in vivo. Mechanistically, LncRNA-PACERR activate KLF12/p-AKT/c-myc pathway by binding to miR-671-3p. And LncRNA-PACERR which bound to IGF2BP2 acts as an m6A-dependent manner to enhance the stability of KLF12 and c-myc in cytoplasm. In addition, the promoter of LncRNA-PACERR was a target of KLF12 and LncRNA-PACERR recruited EP300 to increase the acetylation of histone by interacting with KLF12 in nucleus. Conclusions: This study found that LncRNA-PACERR functions as key regulator of TAMs in PDAC microenvironment and revealed the novel mechanisms in cytoplasm and in nucleus. [ABSTRACT FROM AUTHOR]

Background: Tumour‐associated macrophages (TAMs) play an important role in promoting the progression of pancreatic ductal adenocarcinoma (PDAC). Here, we aimed to study the epigenetic mechanisms in regulating pro‐tumour M2‐polarised TAMs in the PDAC tumour microenvironment. Methods: This study was conducted based on ex vivo TAMs isolated from PDAC tissues and in vitro THP1‐derived TAM model. RNA‐sequencing (RNA‐seq), assay for transposase‐accessible chromatin with sequencing and chromatin immunoprecipitation sequencing were performed to investigate gene expression, chromatin accessibility, transcription factor binding sites and histone modifications. Gene knockdown in THP1‐derived TAMs was performed with lentivirus, and the impact of THP1‐derived TAMs on invasion and metastasis ability of PDAC cells were investigated with in vitro and in vivo functional assays. RNA‐chromatin interaction was analysed by chromatin isolation through RNA purification with sequencing. RNA‐protein interaction was studied by RNA immunoprecipitation and RNA pull‐down. Results: Our data showed that the transcription factor CTCF (CCCTC‐binding factor) was highly expressed in TAMs and predicted to be significantly enriched in hyper‐accessible chromatin regions when compared to monocytes. High infiltration of CTCF+ TAMs was significantly associated with poor prognosis in PDAC patients. Knockdown of CTCF in THP1‐derived TAMs led to the down‐regulation of specific markers for M2‐polarised TAMs, including CD206 and CD163. When THP1‐derived TAMs with CTCF knockdown, they showed a decreased ability of invasion and metastasis. Further integrative analysis of multi‐omics data revealed that prostaglandin‐endoperoxide synthase 2 (PTGS2) and PTGS2 antisense NF‐κB1 complex‐mediated expression regulator RNA (PACERR) were critical downstream targets of CTCF and positively correlated with each other, which are closely situated on a chromosome. Knockdown of PACERR exhibited a similar phenotype as observed in CTCF knockdown THP1‐derived TAMs. Moreover, PACERR could directly bind to CTCF and recruit histone acetyltransferase E1A binding protein p300 to the promoter regions of PACERR and PTGS2, thereby enhancing histone acetylation and gene transcription, promoting the M2 polarization of TAMs in PDAC. Conclusions: Our study demonstrated a novel epigenetic regulation mechanism of promoting pro‐tumour M2‐polarised TAMs in the PDAC tumour microenvironment. [ABSTRACT FROM AUTHOR]

This study aimed to explore novel long non-coding RNAs (lncRNAs) and the underlying mechanisms involved in childhood acute lymphoblastic leukemia (cALL). The GSE67684 dataset was downloaded from the Gene Expression Omnibus. Differentially expressed genes (DEGs) and lncRNAs (DELs) between Days 0, 8, 15 and 33 were isolated using random variance model corrective analysis of variance. Overlapping DEGs and DELs were clustered using Cluster 3.0. Bio-functional enrichment analysis was performed using Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG). Interactions between lncRNAs and mRNAs were calculated using dynamic simulations, and interactions among mRNAs were predicted using the STRING database. lncRNA-mRNA and protein-protein interaction (PPI) networks were visualized using Cytoscape. Subsequently, the expression levels of lncRNAs in biological samples from children with or without cALL were validated using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). A total of 593 overlapping DEGs and 21 DELs were identified. After clustering, Profile 26 exhibited a continuously increasing temporal trend, whereas Profile 1 exhibited a continuous decreasing trend. Upregulated DEGs were significantly enriched in 1,825 GO terms and 166 KEGG pathways, whereas downregulated DEGs were significantly enriched in 196 GO terms and 90 KEGG pathways. The lncRNAs NONHSAT027612.2 and NONHSAT134556.2 were the top two regulators in the lncRNA-mRNA network. Toll-like receptor 4, cathepsin G, nucleotide-binding oligomerization domain containing 2 and cathepsin S may be considered the hub genes of the PPI network. RT-qPCR results indicated that the expression levels of the lncRNAs NONHSAT027612.2 and NONHSAT134556.2 were significantly elevated in the blood and bone marrow of patients with cALL compared with the controls. In conclusion, the lncRNAs NONHSAT027612.2 and NONHSAT134556.2 may serve important roles in the pathogenesis of cALL via regulating immune response-associated pathways. [ABSTRACT FROM AUTHOR]

Background. Contrast-induced acute kidney injury (CI-AKI) is one of the main causes of iatrogenic acute kidney injury (AKI); however, therapeutic strategies for AKI remain limited. This study aims to explore the effect of relaxin (RLX) on contrast-induced HK-2 apoptosis and its underlying mechanisms. Methods. Renal tubular epithelial cells (HK-2) were incubated either with or without ioversol, human H2 relaxin, and LY294002 (the inhibitor of the PI3K/Akt signal pathway). Cell viability was evaluated with a CCK-8 assay. Apoptotic morphologic alterations were observed using the Hoechst 33342 staining method. Apoptosis was detected with Annexin V staining. Western blot analysis was employed to measure the expression of pAkt (S473), Akt, cleaved caspase-3, Bcl-2, Bax, and actin proteins. Results. Ioversol reduced the viability of HK-2 cells. Western blotting results revealed decreased expression of phosphorylated Akt in cells treated with ioversol. The activities of caspase-3 and Bax protein increased, while the expression of Bcl-2 protein decreased. As a result, the Bax/Bcl-2 ratio increased after treatment with ioversol. These effects were reversed when HK-2 cells were cotreated with RLX. However, with preadministration of PI3K/Akt pathway inhibitor LY294002, the effect of RLX was blocked. Conclusion. Our study demonstrates that relaxin attenuates ioversol induced cell apoptosis via activation of the PI3K/Akt signaling pathway, suggesting that RLX might play a protective role in the treatment of CI-AKI. [ABSTRACT FROM AUTHOR]

A hyperspectral image classification method based on a mixed structure with a 3D multi-shortcut-link network (MSLN) was proposed for the features of few labeled samples, excess noise, and heterogeneous homogeneity of features in hyperspectral images. First, the spatial–spectral joint features of hyperspectral cube data were extracted through 3D convolution operation; then, the deep network was constructed and the 3D MSLN mixed structure was used to fuse shallow representational features and deep abstract features, while the hybrid activation function was utilized to ensure the integrity of nonlinear data. Finally, the global self-adaptive average pooling and L-softmax classifier were introduced to implement the terrain classification of hyperspectral images. The mixed structure proposed in this study could extract multi-channel features with a vast receptive field and reduce the continuous decay of shallow features while improving the utilization of representational features and enhancing the expressiveness of the deep network. The use of the dropout mechanism and L-softmax classifier endowed the learned features with a better generalization property and intraclass cohesion and interclass separation properties. Through experimental comparative analysis of six groups of datasets, the results showed that this method, compared with the existing deep-learning-based hyperspectral image classification methods, could satisfactorily address the issues of degeneration of the deep network and "the same object with distinct spectra, and distinct objects with the same spectrum." It could also effectively improve the terrain classification accuracy of hyperspectral images, as evinced by the overall classification accuracies of all classes of terrain objects in the six groups of datasets: 97.698%, 98.851%, 99.54%, 97.961%, 97.698%, and 99.138%. [ABSTRACT FROM AUTHOR]