scholarly journals The Splicing Factor SF2 Is Critical for Hyperproliferation and Survival in a TORC1-Dependent Model of Early Tumorigenesis in Drosophila

2020 ◽  
Vol 21 (12) ◽  
pp. 4465
Author(s):  
Malgorzata Maria Parniewska ◽  
Hugo Stocker
Keyword(s):  
Cellular Growth ◽  
Splicing Factor ◽  
Limiting Factor ◽  
Growth Factor Signaling ◽  
Dependent Manner ◽  
Development Of Resistance ◽  
Nutritional Conditions ◽  
Downstream Effectors ◽  
Cancer Types ◽  
Dependent Model

The Target of Rapamycin complex 1 (TORC1) is an evolutionarily conserved kinase complex coordinating cellular growth with nutritional conditions and growth factor signaling, and its activity is elevated in many cancer types. The use of TORC1 inhibitors as anticancer drugs is, however, limited by unwanted side-effects and development of resistance. We therefore attempted to identify limiting modulators or downstream effectors of TORC1 that could serve as therapeutic targets. Drosophila epithelial tissues that lack the tumor suppressor Pten hyperproliferate upon nutrient restriction in a TORC1-dependent manner. We probed candidates of the TORC1 signaling network for factors limiting the overgrowth of Pten mutant tissues. The serine/arginine-rich splicing factor 2 (SF2) was identified as the most limiting factor: SF2 knockdown drives Pten mutant cells into apoptosis, while not affecting control tissue. SF2 acts downstream of or in parallel to TORC1 but is not required for the activation of the TORC1 target S6K. Transcriptomics analysis revealed transcripts with alternatively used exons regulated by SF2 in the tumor context, including p53. SF2 may therefore represent a highly specific therapeutic target for tumors with hyperactive TORC1 signaling.

scholarly journals Glycolipid-dependent and lectin-driven transcytosis in mouse enterocytes

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Alena Ivashenka ◽  
Christian Wunder ◽  
Valerie Chambon ◽  
Roger Sandhoff ◽  
Richard Jennemann ◽  
...  
Keyword(s):  
Basolateral Membrane ◽  
Intestinal Barrier ◽  
Growth Factor Signaling ◽  
Dependent Manner ◽  
Galectin 3 ◽  
Cell Adhesion And Migration ◽  
Range Of Functions ◽  
Mouse Intestine ◽  
And Migration

AbstractGlycoproteins and glycolipids at the plasma membrane contribute to a range of functions from growth factor signaling to cell adhesion and migration. Glycoconjugates undergo endocytic trafficking. According to the glycolipid-lectin (GL-Lect) hypothesis, the construction of tubular endocytic pits is driven in a glycosphingolipid-dependent manner by sugar-binding proteins of the galectin family. Here, we provide evidence for a function of the GL-Lect mechanism in transcytosis across enterocytes in the mouse intestine. We show that galectin-3 (Gal3) and its newly identified binding partner lactotransferrin are transported in a glycosphingolipid-dependent manner from the apical to the basolateral membrane. Transcytosis of lactotransferrin is perturbed in Gal3 knockout mice and can be rescued by exogenous Gal3. Inside enterocytes, Gal3 is localized to hallmark structures of the GL-Lect mechanism, termed clathrin-independent carriers. These data pioneer the existence of GL-Lect endocytosis in vivo and strongly suggest that polarized trafficking across the intestinal barrier relies on this mechanism.

scholarly journals Global Expression Profiling and Physiological Characterization of Corynebacterium glutamicum Grown in the Presence of l-Valine

2003 ◽  
Vol 69 (5) ◽  
pp. 2521-2532 ◽  
Author(s):  
C. Lange ◽  
D. Rittmann ◽  
V. F. Wendisch ◽  
M. Bott ◽  
H. Sahm
Keyword(s):  
Corynebacterium Glutamicum ◽  
Expression Profiling ◽  
Large Subunit ◽  
Mrna Level ◽  
Acetohydroxyacid Synthase ◽  
Limiting Factor ◽  
Unexpected Result ◽  
Dependent Manner ◽  
Wild Type ◽  
Concentration Dependent Manner

ABSTRACT Addition of l-valine (50 to 200 mM) to glucose minimal medium had no effect on the growth of wild-type Corynebacterium glutamicum ATCC 13032 but inhibited the growth of the derived valine production strain VAL1 [13032 ΔilvA ΔpanBC(pJC1ilvBNCD)] in a concentration-dependent manner. In order to explore this strain-specific valine effect, genomewide expression profiling was performed using DNA microarrays, which showed that valine caused an increased ilvBN mRNA level in VAL1 but not in the wild type. This unexpected result was confirmed by an increased cellular level of the ilvB protein product, i.e., the large subunit of acetohydroxyacid synthase (AHAS), and by an increased AHAS activity of valine-treated VAL1 cells. The conclusion that valine caused the limitation of another branched-chain amino acid was confirmed by showing that high concentrations of l-isoleucine could relieve the valine effect on VAL1 whereas l-leucine had the same effect as valine. The valine-caused isoleucine limitation was supported by the finding that the inhibitory valine effect was linked to the ilvA deletion that results in isoleucine auxotrophy. Taken together, these results implied that the valine effect is caused by competition for uptake of isoleucine by the carrier BrnQ, which transports all branched-chained amino acids. Indeed, valine inhibition could also be relieved by supplementing VAL1 with the dipeptide isoleucyl-isoleucine, which is taken up by a dipeptide transport system rather than by BrnQ. Interestingly, addition of external valine stimulated valine production by VAL1. This effect is most probably due to a reduced carbon usage for biomass production and to the increased expression of ilvBN, indicating that AHAS activity may still be a limiting factor for valine production in the VAL1 strain.

scholarly journals Targeting KRAS: The Elephant in the Room of Epithelial Cancers

2021 ◽  
Vol 11 ◽  
Author(s):  
Valeria Merz ◽  
Marina Gaule ◽  
Camilla Zecchetto ◽  
Alessandro Cavaliere ◽  
Simona Casalino ◽  
...  
Keyword(s):  
Checkpoint Inhibitors ◽  
Small Cell Lung ◽  
Synthetic Lethal ◽  
Adaptive Resistance ◽  
Epithelial Cancers ◽  
Combination Strategies ◽  
Downstream Effectors ◽  
Cancer Types ◽  
Direct Targeting

Mutations of the proto-oncogene KRAS are the most frequent gain-of-function alterations found in cancer. KRAS is mutated in about 30% of all human tumors, but it could reach more than 90% in certain cancer types such as pancreatic adenocarcinoma. Although historically considered to be undruggable, a particular KRAS mutation, the G12C variant, has recently emerged as an actionable alteration especially in non-small cell lung cancer (NSCLC). KRASG12C and pan-KRAS inhibitors are being tested in clinical trials and have recently shown promising activity. Due to the difficulties in direct targeting of KRAS, other approaches are being explored. The inhibition of target upstream activators or downstream effectors of KRAS pathway has shown to be moderately effective given the evidence of emerging mechanisms of resistance. Various synthetic lethal partners of KRAS have recently being identified and the inhibition of some of those might prove to be successful in the future. The study of escape mechanisms to KRAS inhibition could support the utility of combination strategies in overcoming intrinsic and adaptive resistance and enhancing clinical benefit of KRASG12C inhibitors. Considering the role of the microenvironment in influencing tumor initiation and promotion, the immune tumor niche of KRAS mutant tumors has been deeply explored and characterized for its unique immunosuppressive skewing. However, a number of aspects remains to be fully understood, and modulating this tumor niche might revert the immunoresistance of KRAS mutant tumors. Synergistic associations of KRASG12C and immune checkpoint inhibitors are being tested.

scholarly journals picd-1, a gene that encodes CABIN1 domain-containing protein, interacts with pry-1/Axin to regulate multiple processes in Caenorhabditis elegans

2021 ◽  
Author(s):  
Avijit Mallick ◽  
Shane K. B. Taylor ◽  
Sakshi Mehta ◽  
Bhagwati P. Gupta
Keyword(s):  
Stress Response ◽  
Essential Role ◽  
Family Members ◽  
Transcriptome Profiling ◽  
Scaffolding Protein ◽  
Dependent Manner ◽  
C Elegans ◽  
Downstream Effectors ◽  
Cellular Components

ABSTRACTAXIN family members control diverse biological processes in eukaryotes. As a scaffolding protein, AXIN facilitates interactions between cellular components and provides specificity to signaling pathways. Despite its crucial roles in metazoans and discovery of a large number of family members, the mechanism of AXIN function is not very well understood. The C. elegans AXIN homolog PRY-1 provides a powerful tool to identify interacting genes and downstream effectors that function in a conserved manner to regulate AXIN-mediated signaling. Previous work demonstrated pry-1’s essential role in developmental processes such as reproductive system, seam cells, and a P lineage cell P11.p. More recently, our lab carried out a transcriptome profiling of pry-1 mutant and uncovered the essential role of the gene in lipid metabolism, stress response, and aging. In this study, we have extended the work on pry-1 by reporting a novel interacting gene picd-1 (pry-1-interacting CABIN1 domain containing). Our findings have revealed that picd-1 plays an essential role in C. elegans and is involved in several pry-1-mediated processes including regulation of stress response and lifespan maintenance. In support of this, picd-1 expression overlaps with pry-1 in multiple tissues throughout the lifespan of animals. Further experiments showed that picd-1 inhibits CREB-regulated transcriptional coactivator homolog CRTC-1 function, which promotes longevity in a calcineurin-dependent manner. These data provide evidence for an essential role of the CABIN1 domain protein PICD-1 in mediating PRY-1 signaling in C. elegans.

scholarly journals ASF1B Promotes Oncogenesis in Lung Adenocarcinoma and Other Cancer Types

2021 ◽  
Vol 11 ◽  
Author(s):  
Wencheng Zhang ◽  
Zhouyong Gao ◽  
Mingxiu Guan ◽  
Ning Liu ◽  
Fanjie Meng ◽  
...  
Keyword(s):  
Lung Adenocarcinoma ◽  
Immune Cell ◽  
Gene Set Enrichment Analysis ◽  
The Cancer Genome Atlas ◽  
Tumor Promoter ◽  
Regulatory Subunit ◽  
Cell Cycle Distribution ◽  
Cancer Type ◽  
Dependent Manner ◽  
Cancer Types

Anti-silencing function 1B histone chaperone (ASF1B) is known to be an important modulator of oncogenic processes, yet its role in lung adenocarcinoma (LUAD) remains to be defined. In this study, an integrated assessment of The Cancer Genome Atlas (TCGA) and genotype-tissue expression (GTEx) datasets revealed the overexpression of ASF1B in all analyzed cancer types other than LAML. Genetic, epigenetic, microsatellite instability (MSI), and tumor mutational burden (TMB) analysis showed that ASF1B was regulated by single or multiple factors. Kaplan-Meier survival curves suggested that elevated ASF1B expression was associated with better or worse survival in a cancer type-dependent manner. The CIBERSORT algorithm was used to evaluate immune microenvironment composition, and distinct correlations between ASF1B expression and immune cell infiltration were evident when comparing tumor and normal tissue samples. Gene set enrichment analysis (GSEA) indicated that ASF1B was associated with proliferation- and immunity-related pathways. Knocking down ASF1B impaired the proliferation, affected cell cycle distribution, and induced cell apoptosis in LUAD cell lines. In contrast, ASF1B overexpression had no impact on the malignant characteristics of LUAD cells. At the mechanistic level, ASF1B served as an indirect regulator of DNA Polymerase Epsilon 3, Accessory Subunit (POLE3), CDC28 protein kinase regulatory subunit 1(CKS1B), Dihydrofolate reductase (DHFR), as established through proteomic profiling and Immunoprecipitation-Mass Spectrometry (IP-MS) analyses. Overall, these data suggested that ASF1B serves as a tumor promoter and potential target for cancer therapy and provided us with clues to better understand the importance of ASF1B in many types of cancer.

scholarly journals High-dose vitamin C enhances cancer immunotherapy

2020 ◽  
Vol 12 (532) ◽  
pp. eaay8707 ◽  
Author(s):  
Alessandro Magrì ◽  
Giovanni Germano ◽  
Annalisa Lorenzato ◽  
Simona Lamba ◽  
Rosaria Chilà ◽  
...  
Keyword(s):  
Immune System ◽  
Vitamin C ◽  
Clinical Evidence ◽  
High Dose ◽  
Dependent Manner ◽  
Cancer Cell Growth ◽  
Mutational Burden ◽  
Cancer Types ◽  
High Doses ◽  
High Dose Vitamin

Vitamin C (VitC) is known to directly impair cancer cell growth in preclinical models, but there is little clinical evidence on its antitumoral efficacy. In addition, whether and how VitC modulates anticancer immune responses is mostly unknown. Here, we show that a fully competent immune system is required to maximize the antiproliferative effect of VitC in breast, colorectal, melanoma, and pancreatic murine tumors. High-dose VitC modulates infiltration of the tumor microenvironment by cells of the immune system and delays cancer growth in a T cell–dependent manner. VitC not only enhances the cytotoxic activity of adoptively transferred CD8 T cells but also cooperates with immune checkpoint therapy (ICT) in several cancer types. Combination of VitC and ICT can be curative in models of mismatch repair–deficient tumors with high mutational burden. This work provides a rationale for clinical trials combining ICT with high doses of VitC.

scholarly journals Healthspan Improvements in Caenorhabditis elegans with Traditional Chinese Herbal Tea

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Chunxiu Lin ◽  
Xiaoying Zhang ◽  
Chuting Zhuang ◽  
Yugui Lin ◽  
Yong Cao ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Disease Risk ◽  
Underlying Mechanism ◽  
Protective Mechanism ◽  
Growth Factor Signaling ◽  
Dependent Manner ◽  
Herbal Tea ◽  
Main Components ◽  
Chinese Herbal Tea ◽  
Late Stages

Searching for natural and safe herbal tea with health benefits has attracted more and more attention, which is of great significance for reducing disease risk. A Chinese traditional herbal tea (HT) is rich in active ingredients extracted from natural plants. Numerous pharmacological studies showed that HT had the potential to improve health, including antidepression and antioxidant effects. In this study, we proposed a strategy to explore the role and underlying mechanism of HT in improving healthspan of a Caenorhabditis elegans model. First, we found that HT significantly prolonged the lifespan without reducing fertility in worms. Second, stress resistance (oxidative stress and heat stress) was enhanced and Aβ- and polyQ-induced toxicity was relieved significantly by HT treatment. Both fat deposition and age pigment accumulation were found to be significantly reduced in HT-treated worms. The locomotion in mid-late stages was improved, indicating that behavioral mobility was also significantly enhanced. Furthermore, the main components of HT were eighteen polyphenols and two terpenoids. Finally, it was found that this protective mechanism was positively correlated with the insulin/insulin-like growth factor signaling- (IIS-) dependent manner, which went through promoting the nuclear localization of DAF-16 and its downstream SOD-3 expression. These results suggested that HT had an important role in improving health, which might serve as a promising healthy tea.

scholarly journals Taurolidine Acts on Bacterial Virulence Factors and Does Not Induce Resistance in Periodontitis-Associated Bacteria—An In-Vitro Study

Antibiotics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 166
Author(s):  
Sabrina Radakovic ◽  
Nicola Andreoli ◽  
Simon Schmid ◽  
Sandor Nietzsche ◽  
Jürg Zumbrunn ◽  
...  
Keyword(s):  
Virulence Factors ◽  
Bacterial Species ◽  
Rare Event ◽  
In Vitro Study ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Minimal Inhibitory Concentrations ◽  
Development Of Resistance ◽  
Subinhibitory Concentrations

The aims of the present study were: (a) to determine the mechanism of action of taurolidine against bacterial species associated with periodontal disease, and (b) to evaluate the potential development of resistance against taurolidine as compared with minocycline. After visualizing the mode of action of taurolidine by transmission electron micrographs, the interaction with most important virulence factors (lipopolysaccharide (LPS), Porphyromonas gingivalis gingipains, Aggregatibacter actinomycetemcomitans leukotoxin), was analyzed. Then, 14 clinical isolates from subgingival biofilm samples were transferred on agar plates containing subinhibitory concentrations of taurolidine or minocycline up to 50 passages. Before and after each 10 passages, minimal inhibitory concentrations (MICs) were determined. Increasing MICs were screened for efflux mechanism. Taurolidine inhibited in a concentration-dependent manner the activities of LPS and of the arginine-specific gingipains; however, an effect on A. actinomycetemcomitans leukotoxin was not detected. One P. gingivalis strain developed a resistance against taurolidine, which was probably linked with efflux mechanisms. An increase of MIC values of minocycline occurred in five of the 14 included strains after exposure to subinhibitory concentrations of the antibiotic. The present results indicate that: (a) taurolidine interacts with LPS and gingipains, and (b) development of resistance seems to be a rare event when using taurolidine.

scholarly journals In Silico Analysis of a Highly Mutated Gene in Cancer Provides Insight into Abnormal mRNA Splicing: Splicing Factor 3B Subunit 1K700E Mutant

Biomolecules ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 680 ◽  
Author(s):  
Asmaa Samy ◽  
Baris Suzek ◽  
Mehmet Ozdemir ◽  
Ozge Sensoy
Keyword(s):  
Rna Splicing ◽  
In Silico Analysis ◽  
Therapy Resistance ◽  
Mrna Splicing ◽  
Splicing Factor ◽  
Cancer Types ◽  
Dynamics Simulations ◽  
Aberrant Rna ◽  
The Impact ◽  
Splicing Machinery

Cancer is the second leading cause of death worldwide. The etiology of the disease has remained elusive, but mutations causing aberrant RNA splicing have been considered one of the significant factors in various cancer types. The association of aberrant RNA splicing with drug/therapy resistance further increases the importance of these mutations. In this work, the impact of the splicing factor 3B subunit 1 (SF3B1) K700E mutation, a highly prevalent mutation in various cancer types, is investigated through molecular dynamics simulations. Based on our results, K700E mutation increases flexibility of the mutant SF3B1. Consequently, this mutation leads to i) disruption of interaction of pre-mRNA with SF3B1 and p14, thus preventing proper alignment of mRNA and causing usage of abnormal 3’ splice site, and ii) disruption of communication in critical regions participating in interactions with other proteins in pre-mRNA splicing machinery. We anticipate that this study enhances our understanding of the mechanism of functional abnormalities associated with splicing machinery, thereby, increasing possibility for designing effective therapies to combat cancer at an earlier stage.

scholarly journals The Role of Autophagy in Pancreatic Cancer: From Bench to the Dark Bedside

Cells ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 1063 ◽  
Author(s):  
Kıvanç Görgülü ◽  
Kalliope N. Diakopoulos ◽  
Ezgi Kaya-Aksoy ◽  
Katrin J. Ciecielski ◽  
Jiaoyu Ai ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Fine Tuning ◽  
Cancer Tissue ◽  
Dependent Manner ◽  
Cancer Associated Fibroblasts ◽  
Preneoplastic Lesions ◽  
Pancreatic Cancer Tissue ◽  
Cancer Types ◽  
Initiation Stage

Pancreatic cancer is one of the deadliest cancer types urgently requiring effective therapeutic strategies. Autophagy occurs in several compartments of pancreatic cancer tissue including cancer cells, cancer associated fibroblasts, and immune cells where it can be subjected to a multitude of stimulatory and inhibitory signals fine-tuning its activity. Therefore, the effects of autophagy on pancreatic carcinogenesis and progression differ in a stage and context dependent manner. In the initiation stage autophagy hinders development of preneoplastic lesions; in the progression stage however, autophagy promotes tumor growth. This double-edged action of autophagy makes it a hard therapeutic target. Indeed, autophagy inhibitors have not yet shown survival improvements in clinical trials, indicating a need for better evaluation of existing results and smarter targeting techniques. Clearly, the role of autophagy in pancreatic cancer is complex and many aspects have to be considered when moving from the bench to the bedside.

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