Genetic Variants That Impact Alternative Polyadenylation in Cancer Represent Candidate Causal Risk Loci.

Alternative polyadenylation (APA) is emerging as a major mechanism of posttranscriptional regulation. APA can impact the development and progression of cancer, suggesting that the genetic determinants of APA might play an important role in regulating cancer risk. Here, we depicted a pan-cancer atlas of human APA quantitative trait loci (apaQTL), containing approximately 0.7 million apaQTLs across 32 cancer types. Systematic multiomics analyses indicated that cancer apaQTLs could contribute to APA regulation by altering poly(A) motifs, RNA-binding proteins (RBP), and chromatin regulatory elements and were preferentially enriched in genome-wide association studies (GWAS)-identified cancer susceptibility loci. Moreover, apaQTL-related genes (aGene) were broadly related to cancer signaling pathways, high mutational burden, immune infiltration, and drug response, implicating their potential as therapeutic targets. Furthermore, apaQTLs were mapped in Chinese colorectal cancer tumor tissues and then screened for functional apaQTLs associated with colorectal cancer risk in 17,789 cases and 19,951 controls using GWAS-ChIP data, with independent validation in a large-scale population consisting of 6,024 cases and 10,022 controls. A multi-ancestry-associated apaQTL variant rs1020670 with a C>G change in DNM1L was identified, and the G allele contributed to an increased risk of colorectal cancer. Mechanistically, the risk variant promoted aberrant APA and facilitated higher usage of DNM1L proximal poly(A) sites mediated by the RBP CSTF2T, which led to higher expression of DNM1L with a short 3'UTR. This stabilized DNM1L to upregulate its expression, provoking colorectal cancer cell proliferation. Collectively, these findings generate a resource for understanding APA regulation and the genetic basis of human cancers, providing insights into cancer etiology. SIGNIFICANCE: Cancer risk is mediated by alternative polyadenylation quantitative trait loci, including the rs1020670-G variant that promotes alternative polyadenylation of DNM1L and increases colorectal cancer risk.

The ALOX5 inhibitor Zileuton regulates tumor-associated macrophage M2 polarization by JAK/STAT and inhibits pancreatic cancer invasion and metastasis.

5-lipoxygenase (encoded by ALOX5) plays an important role in immune regulation. Zileuton is currently the only approved ALOX5 inhibitor. However, the mechanisms of ALOX5 and Zileuton in progression of pancreatic cancer remain unclear. Therefore, we investigated the effects of Zileuton on tumor-associated macrophage M2 polarization and pancreatic cancer invasion and metastasis, both in vivo and in vitro. In bulk RNA sequencing (RNA-seq) and single-cell RNA sequencing (scRNA-seq) analyses, we found a significant association between elevated levels of ALOX5 and poor survival, adverse stages, M2 macrophage infiltration, and the activation of JAK/STAT pathways in macrophages. In clinical samples, immunofluorescence, quantitative real-time PCR and immunohistochemical results verified the high expression of ALOX5 in pancreatic cancer, primarily in macrophages. We constructed PANC-1 human pancreatic cancer cells and macrophages overexpressing ALOX5 using lentivirus. In PANC-1 pancreatic cancer cells, low-dose Zileuton inhibited PANC-1 cell invasion and migration by blocking ALOX5. In macrophages, ALOX5 induced the M2-like phenotype through the JAK/STAT pathway and promoted the chemotaxis of macrophages towards PANC-1 cells, while Zileuton can inhibit these effects. We constructed the nude mouse model of in situ transplantation tumor of pancreatic cancer. After treatment with Zileuton, the mice showed increased survival rates and reduced liver metastasis. These findings indicate that ALOX5 regulates tumor-associated macrophage M2 polarization via the JAK/STAT pathway and promotes invasion and metastasis in pancreatic cancer. Zileuton can inhibit these effects by inhibiting ALOX5. These results provide a theoretical basis for the potential use of Zileuton in the treatment of pancreatic cancer.

microRNA-21-5p from M2 macrophage-derived extracellular vesicles promotes the differentiation and activity of pancreatic cancer stem cells by mediating KLF3.

AIM: Given the fact that tumor-associated macrophage-derived extracellular vesicles (EVs) are attributable to tumor aggressiveness, this research intends to decode the mechanism of M2 macrophage-derived EVs in the differentiation and activities of pancreatic cancer (PaCa) stem cells via delivering microRNA (miR)-21-5p. METHODS: Polarized M2 macrophages were induced, from which EVs were collected and identified. miR-21-5p expression in M2 macrophage-derived EVs was tested. After cell sorting, CD24+CD44+EpCAM+ stem cells were co-cultured with M2 macrophages, in which miR-21-5p was upregulated or downregulated. The effects of M2 macrophage-derived EVs and miR-21-5p on Nanog/octamer-binding transcription factor 4 (Oct4) expression, sphere formation, colony formation, invasion and migration capacities, apoptosis, and in vivo tumorigenic ability were examined. Krüppel-like factor 3 (KLF3) expression and its interaction with miR-21-5p were determined. RESULTS: M2 macrophage-derived EVs promoted PaCa stem cell differentiation and activities. miR-21a-5p was upregulated in M2 macrophage-derived EVs. miR-21a-5p downregulation in M2 macrophage-derived EVs inhibited Nanog/Oct4 expression and impaired sphere-forming, colony-forming, invasion, migration, and anti-apoptosis abilities of PaCa stem cells in vitro and tumorigenic ability in vivo. miR-21-5p targeted KLF3 to mediate the differentiation and activities of PaCa stem cells, and KLF3 was downregulated in PaCa stem cells. CONCLUSION: This work explains that M2 macrophage-derived exosomal miR-21a-5p stimulates differentiation and activity of PaCa stem cells via targeting KLF3, paving a novel way for attenuating PaCa stemness.

Erratum: MicroRNA-374 targets JAM-2 regulates the growth and metastasis of human pancreatic cancer cells.

[This corrects the article on p. 6454 in vol. 11, PMID: 31737197.].

Hypoxia-induced lncRNA CASC9 enhances glycolysis and the epithelial-mesenchymal transition of pancreatic cancer by a positive feedback loop with AKT/HIF-1α signaling.

Increasing evidence indicates the dysregulations and pivotal roles of lncRNAs in the development and progression of various cancers, including pancreatic cancer. Enhanced glycolytic flux and epithelial-to-mesenchymal transition (EMT) have been considered as important factors in driving the malignance of pancreatic cancer. Here, we sought to evaluate the biological role and involved mechanism of lncRNA CASC9 (CASC9) in pancreatic cancer. Our present study showed that CASC9 was upregulated in various pancreatic cancer cell lines. Loss- and gain-of function of CASC9 demonstrated its critical roles in promoting the glycolysis and EMT phenotypes of pancreatic cancer. Moreover, knockdown of CASC9 inhibited the tumorigenicity and metastasis in vivo. Additionally, our findings showed that hypoxia induced the expression of CASC9 and enhanced the binding of HIF-1α to its promoter. We also demonstrated that the positive feedback loop of CASC9 and the AKT/HIF-1α signaling cascade partially mediated this biological process. Altogether, our results suggest that CASC9 promotes the glycolysis and EMT of pancreatic cancer by a positive feedback loop with AKT/HIF-1α signaling, which is synergistically enhanced by the tumor hypoxic niche. Our study will provide potential therapeutic targets for treating pancreatic cancer.

Intelligent difficulty scoring and assistance system for endoscopic extraction of common bile duct stones based on deep learning: multicenter study.

BACKGROUND: The study aimed to construct an intelligent difficulty scoring and assistance system (DSAS) for endoscopic retrograde cholangiopancreatography (ERCP) treatment of common bile duct (CBD) stones. METHODS: 1954 cholangiograms were collected from three hospitals for training and testing the DSAS. The D-LinkNet34 and U-Net were adopted to segment the CBD, stones, and duodenoscope. Based on the segmentation results, the stone size, distal CBD diameter, distal CBD arm, and distal CBD angulation were estimated. The performance of segmentation and estimation was assessed by mean intersection over union (mIoU) and average relative error. A technical difficulty scoring scale, which was used for assessing the technical difficulty of CBD stone removal, was developed and validated. We also analyzed the relationship between scores evaluated by the DSAS and clinical indicators including stone clearance rate and need for endoscopic papillary large-balloon dilation (EPLBD) and lithotripsy. RESULTS: The mIoU values of the stone, CBD, and duodenoscope segmentation were 68.35 %, 86.42 %, and 95.85 %, respectively. The estimation performance of the DSAS was superior to nonexpert endoscopists. In addition, the technical difficulty scoring performance of the DSAS was more consistent with expert endoscopists than two nonexpert endoscopists. A DSAS assessment score ≥ 2 was correlated with lower stone clearance rates and more frequent EPLBD. CONCLUSIONS: An intelligent DSAS based on deep learning was developed. The DSAS could assist endoscopists by automatically scoring the technical difficulty of CBD stone extraction, and guiding the choice of therapeutic approach and appropriate accessories during ERCP.

MicroRNA-374 targets JAM-2 regulates the growth and metastasis of human pancreatic cancer cells.

Pancreatic cancer is one of the devastating human cancers responsible for tremendous human mortality. Current study was undertaken to explore the therapeutic potential of microRNA-374 in human pancreatic cancer. The results showed that microRNA-374 exhibited lower expression in pancreatic cancer cells and tissues. Overexpression of microRNA-374 in cancer cells resulted in significant decrease in the cell viability. The inhibition of the cell viability was mainly due to the induction of apoptosis as evident from the DAPI and AO/EB staining. Annexin V/PI staining also showed that the overexpression of microRNA-374 enhanced the percentage of apoptotic cells. The western blot analysis showed that microRNA-374 overexpression increases Bax and decreased the Bcl-2 expression. The cleaved PARP and Cleaved caspase-3 expression was also considerably increased upon miR-374 overexpression. The TargetScan analysis together with the dual luciferase assay showed that microRNA-374 targets JAM-2 by binding to mRNA at 3'-UTR. The qRT-PCR analysis showed that JAM-2 was significantly upregulated in the pancreatic cancer cell lines and tissues. Moreover, Overexpression of miR-374 suppressed the expression of JAM-2. Additionally, suppression of JAM-2 also inhibited the viability of the pancreatic cancer cells. In vivo studies in xenografted mice models showed that microRNA-374 expression is effective in suppressing the growth and volume of pancreatic tumors. In conclusion, microRNA-374 is downregulated in pancreatic cancers and may exhibit therapeutic implications in the pancreatic cancer treatment.

Inhibition of COX-2 and 5-LOX regulates the progression of colorectal cancer by promoting PTEN and suppressing PI3K/AKT pathway.

For colorectal cancer (CRC) patients, local and systemic inflammatory responses have been extensively reported to closely associate with patient survival. However, the specific signaling pathways responsible for carcinogenic responses are unclear. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a negative regulator of PI3K/AKT pathway that is gradually inactivated in cancers through mutation, loss of heterozygosity and others epigenetic mechanisms. In addition, COX and LOX metabolic pathways of arachidonic acid (AA) play a crucial role in promoting adenoma development. The aim of this study is to clarify the relationship of COX, LOX and PTEN/PI3K/AKT pathway. Results showed that the over-expressed COX and LOX in cancer cells can be targeted to decrease the expression of PTEN. After using corresponding inhibitors, this condition was significantly improved and promoted apoptosis, inhibited invasion, proliferation and the production of reactive oxygen species. And for COX-2-/- or 5-LOX-/- ApcMin/+ mice, the PI3K/AKT pathway was further inhibited via promoting PTEN. Furthermore, weakened oxidative stress, inhibited adenoma growth, and improved survival rate. All findings indicated that PTEN was indirectly targeted by these enzyme inhibitors and acted as the potential therapeutic target for colorectal cancer therapy. In short, COX-2 or 5-LOX deletion and its inhibitors enhanced activity of PTEN and suppressed cell and adenoma progression through PI3K/AKT pathway in colorectal cancer.

The early prognostic value of inflammatory markers in patients with acute pancreatitis.

OBJECTIVES: The aim of this study was to compare the prognostic value of inflammation-based prognostic markers with the more mature scoring system BISAP in patients with AP and identify the best predictors. PATIENTS AND METHODS: We retrospectively analysed the data of patients with AP who were treated in our hospital from January 2017 to March 2018 and compared the prognostic value of these inflammation-based prognostic markers with the BISAP score in patients with AP. RESULTS: Higher BISAP score, NLR, PLR, ACC, and BUN gradually increased (all P < 0.05), and lower LMR and TC (P < 0.001) were associated with severity of AP. Compared with the patients without persistent organ failure, the patients with POF were older (P = 0.049) and had a higher BISAP score (P < 0.001), NLR (P = 0.003), PLR (P < 0.001) and ACC (P = 0.047), BUN (P = 0.011), and creatinine (P = 0.023), RDW (P = 0.021), but lower LMR (P = 0.003) and TC (P < 0.001) at baseline. The BISAP score (OR = 2.117, 95% CI 1.487 to 3.016, P < 0.001), NLR (OR = 1.053, 95% CI: 1.009 to 1.101, P = 0.019) and TC (OR = 0.088, 95% CI: 0.024 to 1.030, P < 0.001) were independent factors for predicting SAP. For predicting the occurrence of POF, TC and PLR had an area under the ROC curve (TC AUC = 0.784, P < 0.001, with a 2.18 cut-off value, PLR AUC = 0.731, P < 0.001, with a 173.13 cut-off value) that was not inferior to the BISAP score (AUC = 0.708), and PLR had the best sensitivity (95.8%), BUN had the best specificity (44.71%), respectively. There is no difference in their predictive value for POF. CONCLUSIONS: NLR and TC are the most powerful markers in this patient series, they have a prognostic value which is not weaker than BISAP, and are equally simple, rapid.

Hypoxia potentiates gemcitabine-induced stemness in pancreatic cancer cells through AKT/Notch1 signaling.

BACKGROUND: Profound chemoresistance remains an intractable obstacle in pancreatic cancer treatment. Pancreatic cancer stem cells (CSCs) and the ubiquitous hypoxic niche have been proposed to account for drug resistance. However, the mechanism involved requires further exploration. This study investigated whether the hypoxic niche enhances gemcitabine-induced stemness and acquired resistance in pancreatic cancer cells by activating the AKT/Notch1 signaling cascade. The therapeutic effects of blockading this signaling cascade on gemcitabine-enriched CSCs were also investigated. METHODS: The expression levels of CSC-associated markers Bmi1 and Sox2 as well as those of proteins involved in AKT/Notch1 signaling were measured by Western blot analysis. The expression level of the pancreatic CSC marker CD24 was measured by flow cytometry. Change in gemcitabine sensitivity was evaluated by the MTT assay. The ability of sphere formation was tested by the sphere-forming assay in stem cell medium. The ability of migration and invasion was detected by the transwell migration/invasion assay. A mouse xenograft model of pancreatic cancer was established to determine the effect of Notch1 inhibition on the killing effect of gemcitabine in vivo. The ability of metastasis was investigated by an in vivo lung metastasis assay. RESULTS: Gemcitabine promoted pancreatic cancer cell stemness and associated malignant phenotypes such as enhanced migration, invasion, metastasis, and chemoresistance. The AKT/Notch1 signaling cascade was activated after gemcitabine treatment and mediated this process. Blockading this pathway enhanced the killing effect of gemcitabine in vivo. However, supplementation with hypoxia treatment synergistically enhanced the AKT/Notch1 signaling pathway and collaboratively promoted gemcitabine-induced stemness. CONCLUSIONS: These findings demonstrate a novel mechanism of acquired gemcitabine resistance in pancreatic cancer cells through induction of stemness, which was mediated by the activation of AKT/Notch1 signaling and synergistically aggravated by the ubiquitous hypoxic niche. Our results might provide new insights for identifying potential targets for reversing chemoresistance in patients with pancreatic cancer.