High-throughput sequencing of circRNAs reveals novel insights into mechanisms of nigericin in pancreatic cancer.

BACKGROUND: Our previous study had proved that nigericin could reduce colorectal cancer cell proliferation in dose- and time-dependent manners by targeting Wnt/ß-catenin signaling. To better elucidate its potential anti-cancer mechanism, two pancreatic cancer (PC) cell lines were exposed to increasing concentrations of nigericin for different time periods, and the high-throughput sequencing was performed to explore the circRNA expression profiles after nigericin exposure on pancreatic cancer (PC) cells. RESULTS: In this study, a total of 183 common differentially expressed circRNAs were identified, and the reliability and validity of the sequencing data were verified by the PCR analysis. According to the parental genes of circRNAs, the GO analysis was performed to predict the most enriched terms in the biological process, cellular components and molecular functions. The KEGG analysis and pathway-pathway network exhibited the potential signal pathways and their regulatory relationships. Meanwhile, a potential competing endogenous RNA (ceRNA) mechanism through a circRNA-miRNA-mRNA network was applied to annotate potential functions of these common differentially expressed circRNAs, and these predicted miRNAs or mRNAs might be involved in nigericin damage. CONCLUSIONS: By the bioinformatics method, our data will facilitate the understanding of nigericin in PC cells, and provide new insight into the molecular mechanism of nigericin toward cancer cells. This is the first report that discusses the potential functions of nigericin in cancers through the bioinformatics method. Our data will facilitate the understanding of nigericin-mediated anti-cancer mechanisms in PC.

Podocalyxin-like protein promotes gastric cancer progression through interacting with RUN and FYVE domain containing 1 protein.

Podocalyxin-like protein (PODXL), a transmembrane glycoprotein with anti-adhesive properties, is associated with an aggressive tumor phenotype and poor prognosis of several cancers. To elucidate the biological significance of PODXL and its molecular mechanism in gastric cancer (GC), we investigated the expression of PODXL in GC samples and assessed its effects on biological behaviors and the related signaling pathways in vitro and in vivo. Moreover, the possible and closely interacted partners of PODXL were identified. Our data showed that the protein or mRNA level of PODXL was significantly upregulated in tissues or serum of GC patients compared with normal-appearing tissues (NAT) or those of healthy volunteers. Overall survival (OS) curves showed that patients with high PODXL levels in tissues or serum had a worse 5-year OS. In vitro, restoring PODXL expression promoted tumor progression by increasing cell proliferation, colony formation, wound healing, migration and invasion, as well as suppressing the apoptosis. Furthermore, the PI3K/AKT, NF-κB and MAPK/ERK signaling pathways were activated. There was a significant positive correlation between PODXL and RUN and FYVE domain containing 1 (RUFY1) expression in tissues or serum. Subsequent mass spectrometry analysis, co-immunoprecipitation assays and western blot analysis identified PODXL/RUFY1 complexes in GC cells, and silencing RUFY1 expression in GC cells significantly attenuated PODXL-induced phenotypes and their underlying signaling pathways. Our results suggested that PODXL promoted GC progression via a RUFY1-dependent signaling mechanism. New GC therapeutic opportunities through PODXL and targeting the PODXL/RUFY1 complex might improve cancer therapy.

Circulating miR-1826 in plasma correlates with circulating tumor cells and is a prognostic marker in colorectal cancer.

Our previous study showed that miR-1826 was a newly identified oncogenic non-coding RNA in colorectal cancer. But the potential relationship between miR-1826 and tumor metastasis has not been fully elucidated. The purpose of this study was to evaluate the clinical significance of circulating miR-1826 and its possible associations with circulating tumor cells in colorectal cancer. Our results first found that serum miR-1826 was significantly upregulated in colorectal cancer patients, compared with that in healthy volunteers ( p = 0.003). Similar results were also found in colorectal cancer with distant metastasis ( p = 0.001) and advanced colorectal cancer ( p < 0.001) patients, respectively. Clinicopathological analysis implied that circulating miR-1826 was positively associated with pT stage ( p = 0.026), lymphatic metastasis ( p = 0.034), distant metastasis ( p = 0.012), and tumor-node-metastasis stage ( p = 0.020). Besides, our univariate and multivariate analyses demonstrated that high serum miR-1826 expression could act as a prognostic and independent factor for overall survival of colorectal cancer patients ( p < 0.05), which led to a poorer 5-year overall survival rate ( p = 0.025). The area under the curve value of circulating miR-1826 was up to 0.848 ± 0.043, which strongly suggested serum miR-1826 as an effective diagnostic biomarker in colorectal cancer patients ( p < 0.001). Our subsequent experiments demonstrated that patients with high level of circulating tumor cells showed a higher level of miR-1826 expression, compared with the circulating tumor cell-negative patients ( p = 0.011). Similar results also showed that the amount of circulating tumor cells in high miR-1826 group was significantly higher than that in low miR-1826 group ( p = 0.001). Furthermore, the relationship between serum miR-1826 and circulating tumor cells was analyzed using SPSS software and a significant logarithmic relationship was found, which meant that circulating miR-1826 closely correlated with the amount of circulating tumor cells in colorectal cancer patient serum ( r = 0.283, p < 0.01). Our findings strongly suggested that serum miR-1826 could serve as an effective and non-invasive biomarker for diagnosis and prognosis of colorectal cancer. Circulating miR-1826 may be an important target in colorectal cancer therapy.

VMP1 related autophagy and apoptosis in colorectal cancer cells: VMP1 regulates cell death.

Vacuole membrane protein 1 (VMP1) is an autophagy-related protein and identified as a key regulator of autophagy in recent years. In pancreatic cell lines, VMP1-dependent autophagy has been linked to positive regulation of apoptosis. However, there are no published reports on the role of VMP1 in autophagy and apoptosis in colorectal cancers. Therefore, to address this gap of knowledge, we decided to interrogate regulation of autophagy and apoptosis by VMP1. We have studied the induction of autophagy by starvation and rapamycin treatment in colorectal cell lines using electron microscopy, immunofluorescence, and immunoblotting. We found that starvation-induced autophagy correlated with an increase in VMP1 expression, that VMP1 interacted with BECLIN1, and that siRNA mediated down-regulation of VMP1-reduced autophagy. Next, we examined the relationship between VMP1-dependent autophagy and apoptosis and found that VMP1 down-regulation sensitizes cells to apoptosis and that agents that induce apoptosis down-regulate VMP1. In conclusion, similar to its reported role in other cell types, VMP1 is an important regulator of autophagy in colorectal cell lines. However, in contrast to its role in pancreatic cell lines, in colorectal cancer cells, VMP1-dependent autophagy appears to be pro-survival rather than pro-cell death.

Interpretable machine learning model to predict surgical difficulty in laparoscopic resection for rectal cancer.

Background: Laparoscopic total mesorectal excision (LaTME) is standard surgical methods for rectal cancer, and LaTME operation is a challenging procedure. This study is intended to use machine learning to develop and validate prediction models for surgical difficulty of LaTME in patients with rectal cancer and compare these models' performance. Methods: We retrospectively collected the preoperative clinical and MRI pelvimetry parameter of rectal cancer patients who underwent laparoscopic total mesorectal resection from 2017 to 2022. The difficulty of LaTME was defined according to the scoring criteria reported by Escal. Patients were randomly divided into training group (80%) and test group (20%). We selected independent influencing features using the least absolute shrinkage and selection operator (LASSO) and multivariate logistic regression method. Adopt synthetic minority oversampling technique (SMOTE) to alleviate the class imbalance problem. Six machine learning model were developed: light gradient boosting machine (LGBM); categorical boosting (CatBoost); extreme gradient boost (XGBoost), logistic regression (LR); random forests (RF); multilayer perceptron (MLP). The area under receiver operating characteristic curve (AUROC), accuracy, sensitivity, specificity and F1 score were used to evaluate the performance of the model. The Shapley Additive Explanations (SHAP) analysis provided interpretation for the best machine learning model. Further decision curve analysis (DCA) was used to evaluate the clinical manifestations of the model. Results: A total of 626 patients were included. LASSO regression analysis shows that tumor height, prognostic nutrition index (PNI), pelvic inlet, pelvic outlet, sacrococcygeal distance, mesorectal fat area and angle 5 (the angle between the apex of the sacral angle and the lower edge of the pubic bone) are the predictor variables of the machine learning model. In addition, the correlation heatmap shows that there is no significant correlation between these seven variables. When predicting the difficulty of LaTME surgery, the XGBoost model performed best among the six machine learning models (AUROC=0.855). Based on the decision curve analysis (DCA) results, the XGBoost model is also superior, and feature importance analysis shows that tumor height is the most important variable among the seven factors. Conclusions: This study developed an XGBoost model to predict the difficulty of LaTME surgery. This model can help clinicians quickly and accurately predict the difficulty of surgery and adopt individualized surgical methods.

Lactobacillus shenzhenensis sp. nov., isolated from a fermented dairy beverage.

Two Lactobacillus strains, designated LY-73(T) and LY-30B, were isolated from a dairy beverage, sold in Shenzhen market, China. The two isolates were Gram-positive, non-spore-forming, non-motile, facultatively anaerobic rods that were heterofermentative and did not exhibit catalase activity. Sequencing of the 16S rRNA, pheS and rpoA genes revealed that the two isolates shared 99.5, 99.8 and 99.9 % sequence similarity, which indicates that they belong to the same species. Phylogenetic analysis demonstrated clustering of the two isolates with the genus Lactobacillus. Strain LY-73(T) showed highest 16S rRNA gene sequence similarities with Lactobacillus harbinensis KACC 12409(T) (97.73%), Lactobacillus perolens DSM 12744(T) (96.96 %) and Lactobacillus selangorensis DSM 13344(T) (93.10 %). Comparative analyses of their rpoA and pheS gene sequences indicated that the novel strains were significantly different from other Lactobacillus species. Low DNA-DNA reassociation values (50.5 %) were obtained between strain LY-73(T) and its phylogenetically closest neighbours. The G+C contents of the DNA of the two novel isolates were 56.1 and 56.5 mol%. Straight-chain unsaturated fatty acids C18 : 1ω9c (78.85 and 74.29 %) were the dominant components, and the cell-wall peptidoglycan was of the l-Lys-d-Asp type. Based on phenotypic characteristics, and chemotaxonomic and genotypic data, the novel strains represent a novel species of the genus Lactobacillus, for which the name Lactobacillus shenzhenensis sp. nov. is proposed, with LY-73(T) ( = CCTCC M 2011481(T) = KACC 16878(T)) as the type strain.

Whole-genome sequence of Staphylococcus aureus strain LCT-SA112.

Staphylococcus aureus is a facultative anaerobic Gram-positive coccal bacterium. S. aureus is the most common species of Staphylococcus to cause staphylococcal infections, which are very common in clinical medicine. Here we report the genome sequence of S. aureus strain LCT-SA112, which was isolated from S. aureus subsp. aureus CGMCC 1.230.

Genome sequences of three species in the family Planctomycetaceae.

Most of the species in the family Planctomycetaceae are of interest for their eukaryotic-like cell structures and characteristics of resistance to extreme environments. Here, we report draft genome sequences of three aquatic parasitic species of this family, Singulisphaera acidiphila (DSM 18658T), Schlesneria paludicola (DSM 18645T), and Zavarzinella formosa (DSM 19928T).

PRKAR2A-derived circular RNAs promote the malignant transformation of colitis and distinguish patients with colitis-associated colorectal cancer.

BACKGROUND: Emerging studies have proved that colonic inflammation caused by refractory inflammatory bowel disease (IBD) can initiate the colitis-associated cancer (CAC), but the transition from inflammation to carcinoma is still largely unknown. METHODS: In this study, mouse colitis and CAC models were established, and the RNA-seq by circRNA microarray was employed to identify the differentially expressed circRNAs and mRNAs in different comparisons (DSS vs. NC and AOM/DSS vs. DSS). The bioinformatics analyses were used to search the common characteristics in mouse colitis and CAC. RESULTS: The K-means clustering algorithm packaged these differential expressed circRNAs into subgroup analysis, and the data strongly implied that mmu_circ_0001109 closely correlated to the pro-inflammatory signals, while mmu_circ_0001845 was significantly associated with the Wnt signalling pathway. Our subsequent data in vivo and in vitro confirmed that mmu_circ_0001109 could exacerbate the colitis by up-regulating the Jak-STAT3 and NF-kappa B signalling pathways, and mmu_circ_0001845 promoted the CAC transformation through the Wnt signalling pathway. By RNA blasting between mice and humans, the human RTEL1- and PRKAR2A-derived circRNAs, which might be considered as homeotic circRNAs of mmu_circ_0001109 and mmu_circ_0001845, respectively, were identified. The clinical data revealed that RTEL1-derived circRNAs had no clinical significance in human IBD and CAC. However, three PRKAR2A-derived circRNAs, which had the high RNA similarities to mmu_circ_0001845, were remarkably up-regulated in CAC tissue samples and promoted the transition from colitis to CAC. CONCLUSIONS: Our results suggested that these human PRKAR2A-derived circRNAs could be novel candidates for distinguishing CAC patients and predicted the prognosis of CAC.

Pretreatment blood biomarkers combined with magnetic resonance imaging predict responses to neoadjuvant chemoradiotherapy in locally advanced rectal cancer.

Aim: To investigate the value of pretreatment blood biomarkers combined with magnetic resonance imaging (MRI) in predicting the efficacy of neoadjuvant chemoradiotherapy (NCRT) in patients with locally advanced rectal cancer (LARC). Methods: This study involved patients with LARC who received NCRT and subsequently underwent total mesenteric excision from June 2015 to June 2021 at the First Affiliated Hospital of Soochow University. Patients with incomplete courses of neoadjuvant therapy, comorbidities with other malignancies or diseases that affect the study outcome, and those who underwent unplanned surgery were ultimately excluded. Laboratory data such as albumin, CEA, various blood cell levels, and MRI related data such as tumor regression grade assessed by magnetic resonance imaging (mrTRG) were collected from the included patients one week prior to NCRT. MrTRG is a common clinical imaging metric used to assess the degree of tumor regression in rectal cancer, primarily based on morphological assessment of residual tumor. Furthermore, pretreatment blood biomarkers such as neutrophil to lymphocyte ratio (NLR), lymphocyte to monocyte ratio (LMR), albumin to fibrinogen ratio (AFR), and prealbumin to fibrinogen ratio (PFR) were assessed. The independent variables for pathologic complete response (pCR) to NCRT were determined by univariate and multivariate logistic regression analyses. Receiver operating characteristic (ROC) curve analysis was used to examine the performance of MRI with or without pretreatment blood biomarkers in predicting pCR using DeLong's method. A nomogram was created and confirmed internally. Results: Fifty-nine individuals with LARC satisfied the inclusion criteria, among which 23 showed pCR after NCRT. Logistic regression analysis demonstrated that pretreatment CEA (≤ 3 µg/L, OR = 0.151, P = 0.039), NLR (OR = 4.205, P = 0.027), LMR (OR = 0.447, P = 0.034), and PFR (OR = 0.940, P = 0.013) were independent predictors of pCR to NCRT. The AUCs of mrTRG alone and mrTRG plus the above four pretreatment blood biomarkers were 0.721 (P =0.0003) and 0.913 (P <0.0001), respectively. The constructed nomogram showed a C-index of 0.914. Conclusion: Pretreatment blood biomarkers combined with MRI can help clinical efforts by better predicting the efficacy of NCRT in patients with locally advanced rectal cancer.

Long non-coding RNA H19X promotes tumorigenesis and metastasis of colorectal cancer through regulating the miR-503-5p/KANK1 axis.

BACKGROUND: It has been well established that the long non-coding RNAs (lncRNAs) plays a critical role in tumor progression. However, the function of these transcripts and mechanisms responsible for their deregulation in colorectal cancer (CRC) remain to be investigated. OBJECTIVE: To explore the potential effect and regulation mechanism of lncRNA H19X in colorectal cancer. METHODS: We predicted and validated long non-coding RNA H19X from microarray data of colorectal cancer tissues. In addition, the biological behaviors of H19X and miR-503-5p on CRC were examined in vitro and in vivo, including MTT, colony formation assay, Hoechst33342 and transwell assay. The mRNA and protein levels of KN Motif and Ankyrin Repeat Domains 1 (KANK1) were analyzed by Quantitative real-time PCR (qRT-PCR), western blotting (WB) assay. Moreover, bioinformatics tools and dual-luciferase reporter assay were applied to demonstrate the relationship between KANK1 and miR-503-5p. RESULTS: H19X was remarkably up-regulated in CRC tissues. Its expression related to tumor size (p = 0.041), lymph node metastasis (p = 0.037), distal metastasis (p = 0.028), advanced TNM stage (p = 0.034) and poor survival in CRC. H19X acted as an oncogenic lncRNA that induced CRC cell proliferation, invasion and metastasis. Through a number of functional studies, we found that H19X silencing inhibited the malignance phenotype of cancer cells through loss of miR-503-5p. Further studies demonstrated that miR-503-5p was involved in the progression of CRC by directly regulating the downstream target KANK1. CONCLUSION: Collectively, the findings of the present study indicate H19X/miR-503-5p/KANK1 axis has critical role in the progression of colorectal cancer, providing an effective prognostic indicator and promising target in treatment of colorectal cancer.

Distribution and clinical significance of Th17 cells in the tumor microenvironment and peripheral blood of pancreatic cancer patients.

This study was designed to investigate the distribution of Th17 cells in the tumor microenvironment and peripheral blood of pancreatic cancer patients, its clinical significance, and the expression profile of Th17 cell-associated cytokines. The percentage of Th17 cells detected by flow cytometry analysis (FACS) was significantly higher in 46 pancreatic tumor tissues (5.28 ± 1.65%) compared with corresponding adjacent normal tissues (2.57 ± 0.83%) (P = 0.031). In addition, the percentage of Th17 cells was significantly higher in stage III-IV tumors than stage I-II tumors (P = 0.039). The percentage of Th17 cells in peripheral blood of 20 pancreatic cancer patients (3.99 ± 1.15%) was significantly higher than 15 healthy volunteers (1.98 ± 0.57%) (P = 0.027). Immunohistochemistry (IHC) was performed to detect IL-17(+) cells in 46 pancreatic tumor tissues, as well as expression of CD34 in 24 tumor tissues. IL-17 was shown to mainly locate in cytoplasm, and the frequency of IL-17(+) cells in tumor tissues (39/46) was higher than control (29/46). The presence of IL-17(+) cells in tumor tissues was associated with tumor, node, and metastasis (TNM) stage, and lymph node metastasis (P = 0.012 and P = 0.009) but not with patient sex, age, tumor size, and histological grade (P > 0.05). Interestingly, distribution of Th17 cells in tumor tissues was positively correlated with microvessel density (MVD) (r = 0.86, P = 0.018). Furthermore, the median survival time of patients with high and low level of IL-17(+) cells frequency was 14.5 and 18.5 months respectively (P = 0.023). The serum levels of Th17 cell-associated cytokines, IL-17 and IL-23 in 20 pancreatic patients detected by enzyme-linked immunosorbent assay (ELISA) were 69.2 ± 28.5 pg/mL and 266.5 ± 98.1 pg/mL, respectively, which were significantly higher than 15 healthy volunteers (P = 0.015 and P = 0.02). Moreover, levels of IL-17 and IL-23 were significantly higher in stage III-IV tumors than stage I-II tumors (P = 0.04 and P = 0.036). This study suggests that increase in Th17 cells frequency and its related cytokines levels in pancreatic tumor tissues may indicate involvement in the invasion and metastasis of pancreatic cancer, which may thereby affect patient prognosis. Therefore, Th17 cells and related cytokines may be served as important immune indicators for predicting the prognosis of pancreatic cancer patients.

Evidence of nigericin as a potential therapeutic candidate for cancers: A review.

Emerging studies have shown that nigericin, an H+, K+ and Pb2+ ionophore, has exhibited a promising anti-cancer activity in various cancers. However, its anti-cancer mechanisms have not been fully elucidated. In this review, the recent progresses on the use of nigericin in human cancers have been summarized. By exchanging H+ and K+ across cell membranes, nigericin shows promising anti-cancer activities in in vitro and in vivo as a single agent or in combination with other anti-cancer drugs through decreasing intracellular pH (pHi). The underlying mechanisms of nigericin also include the inactivation of Wnt/ß-catenin signals, blockade of Androgen Receptor (AR) signaling, and activation of Stress-Activated Protein Kinase/c-Jun N-terminal Kinase (SAPK/JNK) signaling pathways. In many cancers, nigericin is proved to specifically target putative Cancer Stem Cells (CSCs), and its synergistic effects on photodynamic therapy are also reported. Other mechanisms of nigericin including influencing the mitochondrial membrane potentials, inducing an increase in drug accumulation and autophagy, controlling insulin accumulation in nuclei, and increasing the cytotoxic activity of liposome-entrapped drugs, are also discussed. Notably, the potential adverse effects such as teratogenic effects, insulin resistance and eryptosis shall not be ignored. Taken together, these reports suggest that treatment of cancer cells with nigericin may offer a novel therapeutic strategy and future potential of translation to clinics.

Circular RNA profiling identifies circ102049 as a key regulator of colorectal liver metastasis.

Circular RNA (circRNA) plays an essential role in the development and progression of various cancers. However, the functions and mechanisms of circRNA in colorectal liver metastasis have not been fully elucidated. We performed circRNA microarray analysis to screen differentially expressed circRNA in the pathology of colorectal liver metastasis. Quantitative real-time PCR was used to detect the expression of hsa_circ_102049 (circ102049) in colorectal cancer (CRC) samples. CRC cells were transfected with circ102049 overexpression vector or small interfering (si)RNA to assess the effects of circ102049 in vitro. Bioinformatics analysis, fluorescence in situ hybridization, RNA immunoprecipitation, RNA pull-down and luciferase reporter assays were conducted to confirm the relationship of circ102049, miR-761, miR-192-3p and FRAS1. The mechanism by which circ102049 recruits and distributes DGCR8 protein in the cytoplasm was also investigated. We found that circ102049 was highly expressed in primary CRC tumors with liver metastasis and closely correlated with the prognosis of patients with CRC. Circ102049 significantly enhanced the adhesion, migration and invasion abilities of CRC cells, and promoted CRC progression via a micro (mi)R-761/miR-192-3p-FRAS1-dependent mechanism. Notably, due to the distribution of DGCR8 protein, circ102049 may also indirectly reduce the levels of mature miR-761 and miR-192-3p in the cytoplasm. In addition, the role of circ102049 in promoting colorectal liver metastasis was confirmed in vivo. Our findings provide new evidence that circ102049 may be a potential prognostic factor in CRC, and that the circ102049-miR-761/miR-192-3p-FRAS1 axis may be an anti-metastatic target for CRC patients.

DAB2IP decreases cell growth and migration and increases sensitivity to chemotherapeutic drugs in colorectal cancer.

BACKGROUND: Colorectal cancer (CRC) is one of the most common cancers worldwide with high rates of invasiveness and mortality. DAB2IP (DOC2/DAB2 interactive protein) is a member of the RAS-GTPase-activating protein (RAS-GAP) family that shows a suppressive effect on cancer progression, is downregulated in several cancers. However, the role of DAB2IP in CRC remains elusive. METHODS: Expression of DAB2IP was evaluated in human CRC tissues using immunohistochemistry (IHC), quantitative real-time reverse transcription PCR (qRT-PCR) and immunoblotting. Knockdown and overexpression of DAB2IP in CRC cells were achieved by transfecting siRNAs and DAB2IP expression vectors and assessed by qRT-PCR and immunoblotting. CCK-8, colony formation, wound-healing, and transwell assays were used to evaluate CRC cell growth, migration, and sensitivity to chemotherapeutic drugs. The cell cycle was analyzed by propidium iodide (PI) staining and flow cytometry. Cell apoptosis was evaluated by Annexin V-DAPI double staining and flow cytometry. The effect of DAB2IP overexpression on tumor formation was explored by an in vivo tumorigenesis assay. Finally, immunoblotting was performed to examine the molecules related to the action of DAB2IP in CRC. RESULTS: Compared with para-cancer tissues, there was a marked decrease of DAB2IP expression in surgically excised CRCs. In cultured CRC cells, enforced expression of DAB2IP inhibited cell growth and migration and sensitized the cells to DNA-acting cisplatin, oxaliplatin, and doxorubicin but not 5-fluorouracil (5-FU). In contrast, knockdown of DAB2IP produced the opposite effect. Moreover, DAB2IP overexpression hindered tumor growth in vivo. We further found that DAB2IP regulated the expression of cell growth, epithelial-mesenchymal transition (EMT), and apoptosis-related proteins in CRC cells and inhibited the phosphorylation of protein kinase B (AKT) and extracellular signal-regulated kinase (ERK). CONCLUSIONS: Expression of DAB2IP inhibited CRC cell growth and migration and sensitized CRC cells to chemotherapeutic drugs. Inhibition of the phosphorylation of AKT and ERK is associated with the effects of DAB2IP expression. Restoration of DAB2IP expression may be a novel target for treating CRC.

Molecular Screening for Nigericin Treatment in Pancreatic Cancer by High-Throughput RNA Sequencing.

Objectives: Nigericin, an antibiotic derived from Streptomyces hygroscopicus, has been proved to exhibit promising anti-cancer effects on a variety of cancers. Our previous study investigated the potential anti-cancer properties in pancreatic cancer (PC), and demonstrated that nigericin could inhibit the cell viabilities in concentration- and time-dependent manners via differentially expressed circular RNAs (circRNAs). However, the knowledge of nigericin associated with long non-coding RNA (lncRNA) and mRNA in pancreatic cancer (PC) has not been studied. This study is to elucidate the underlying mechanism from the perspective of lncRNA and mRNA. Methods: The continuously varying molecules (lncRNAs and mRNAs) were comprehensively screened by high-throughput RNA sequencing. Results: Our data showed that 76 lncRNAs and 172 mRNAs were common differentially expressed in the nigericin anti-cancer process. Subsequently, the bioinformatics analyses, including Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, coding and non-coding co-expression network, cis- and trans-regulation predictions and protein-protein interaction (PPI) network, were applied to annotate the potential regulatory mechanisms among these coding and non-coding RNAs during the nigericin anti-cancer process. Conclusions: These findings provided new insight into the molecular mechanism of nigericin toward cancer cells, and suggested a possible clinical application in PC.

Hsa_circ_101555 functions as a competing endogenous RNA of miR-597-5p to promote colorectal cancer progression.

CircRNAs have been reported to exert momentous roles in regulating pathophysiological process and guiding clinical diagnosis and treatment in colorectal cancer (CRC). However, there are still a lot of circRNAs that need to be unearthed. In this study, we evaluated the expression profile of circRNAs in 10 CRC tissues and their corresponding normal-appearing tissues (NATs) by microarray, and identified that hsa_circ_101555 (circ101555) was significantly up-regulated in tumor tissues and closely related to the prognosis of CRC patients. A specific close loop structure of circ101555 was described, which was generated by back-splicing of the host gene CSNK1G1 and showed greater stability than the linear RNA. The results in vitro and in vivo showed that silencing circ101555 expression significantly suppressed cell proliferation, induced apoptosis and impaired the DNA repair capacity of CRC cells, while rescue experiments suggested that down-expression of miR-597-5p could significantly attenuate the biological effects of circ101555 knockdown on CRC cells. Subsequent experiments in vitro, including double fluorescence in situ hybridization (D-FISH) analysis, RIP analysis and biotin-coupled probe pull down assay, confirmed that miR-597-5p was effectively enriched by circ101555, and circ101555 might serve as a sponge of miR-597-5p. Moreover, two putative oncogenes (CDK6 and RPA3) were identified as the miR-597-5p potential targets. Taken together, our results proved that circ101555 might function as a competing endogenous RNA of miR-597-5p to up-regulate CDK6 and RPA3 expression in CRC. Circ101555 could be a useful prognostic indicator in patients with CRC, and silence of circ101555 provided a new attractive therapeutic measure for CRC.

Alpha-enolase promotes gastric cancer cell proliferation and metastasis via regulating AKT signaling pathway.

Increased aerobic glycolysis is considered as a hallmark of cancer and targeting key glycolytic enzymes will be a promising therapeutic approach in cancer treatment. Alpha-enolase (ENO1), as a prominent glycolytic enzyme, is upregulated in multiple cancers and its overexpression is involved in tumor cell proliferation and metastasis. In the present study, we aimed to investigate the potential role of ENO1 in the development and progression of gastric cancer (GC). Here, we found that ENO1 expression was upregulated in human GC and was associated with Lauren type, lymph node metastasis (LNM) and TNM stage. Knockdown of ENO1 attenuated GC cell proliferation and metastasis and reversed epithelial-mesenchymal transition (EMT) progress in vitro while ENO1 overexpression did the opposite. ENO1 could modulate AKT signaling pathway in GC cells and the enhanced proliferation and migration ability induced by ENO1 overexpression was impaired after incubation with PI3K inhibitor Ly294002 in SGC7901 cells. Our data demonstrated that ENO1 enhances GC cell proliferation and metastasis through the protein kinase B (AKT) signaling pathway, indicating that ENO1/AKT signaling axis may serve as a potential target for treatment of GC.

1,520 reference genomes from cultivated human gut bacteria enable functional microbiome analyses.

Reference genomes are essential for metagenomic analyses and functional characterization of the human gut microbiota. We present the Culturable Genome Reference (CGR), a collection of 1,520 nonredundant, high-quality draft genomes generated from >6,000 bacteria cultivated from fecal samples of healthy humans. Of the 1,520 genomes, which were chosen to cover all major bacterial phyla and genera in the human gut, 264 are not represented in existing reference genome catalogs. We show that this increase in the number of reference bacterial genomes improves the rate of mapping metagenomic sequencing reads from 50% to >70%, enabling higher-resolution descriptions of the human gut microbiome. We use the CGR genomes to annotate functions of 338 bacterial species, showing the utility of this resource for functional studies. We also carry out a pan-genome analysis of 38 important human gut species, which reveals the diversity and specificity of functional enrichment between their core and dispensable genomes.

Nigericin Exerts Anticancer Effects on Human Colorectal Cancer Cells by Inhibiting Wnt/ß-catenin Signaling Pathway.

Nigericin, an antibiotic derived from Streptomyces hygroscopicus, which works by acting as an H+, K+, and Pb2+ ionophore, has exhibited promising anticancer activity. The main purpose of this study is to investigate its inhibitory effects on Wnt/ß-catenin signaling pathway in colorectal cancer cells and clarify the underlying mechanism. We exposed two colorectal cancer lines (SW620 and KM12) to increasing concentrations of nigericin for different time periods and the 50% inhibiting concentration (IC50) values were evaluated. Our data showed that nigericin treatment significantly reduced tumor cell proliferation in dose- and time-dependent manners in colorectal cancer cells. The subsequent experiments in vitro and in vivo implied that nigericin could significantly suppress the tumor growth, migration, and invasion, and induce the apoptosis of colorectal cancer cells. Our results of Western blot and immunofluorescence assay showed that nigericin could suppress the Wnt/ß-catenin signaling pathway in colorectal cancer cells with dose-dependent increased expressions of downstream effectors and target proteins. To further elucidate the inhibitory effects of nigericin via a ß-catenin-dependent signaling mechanism, we established the stably ß-catenin overexpression colorectal cancer cells. Western blot, SuperTOPFlash luciferase reporter, and immunoprecipitation assays all confirmed ß-catenin as a critical intermediary and player in Wnt/ß-catenin pathway, and nigericin exerted anticancer effects on colorectal cancer cells by directly targeting the ß-catenin destruction complex. These results suggested that Wnt/ß-catenin signaling might have an essential role in colorectal cancer progression. Nigericin targeting Wnt/ß-catenin signaling might provide new insight into the molecular mechanism of nigericin toward cancer cells, and suggest possible clinical application in colorectal cancer. Mol Cancer Ther; 17(5); 952-65. ©2018 AACR.