Ribosomally synthesized and post‐translationally modified peptides (RiPPs) are a fascinating group of natural products that exhibit diverse structural features and bioactivities. P450‐catalyzed RiPPs ...stand out as a unique but underexplored family. Herein, we introduce a rule‐based genome mining strategy that harnesses the intrinsic biosynthetic principles of RiPPs, including the co‐occurrence and co‐conservation of precursors and P450s and interactions between them, successfully facilitating the identification of diverse P450‐catalyzed RiPPs. Intensive BGC characterization revealed four new P450s, KstB, ScnB, MciB, and SgrB, that can catalyze the formation of Trp‐Trp‐Tyr (one C−C and two C−N bonds), Tyr‐Trp (C−C bond), Trp‐Trp (C−N bond), and His‐His (ether bond) crosslinks, respectively, within three or four residues. KstB, ScnB, and MciB could accept non‐native precursors, suggesting they could be promising starting templates for bioengineering to construct macrocycles. Our study highlights the potential of P450s to expand the chemical diversity of strained macrocyclic peptides and the range of biocatalytic tools available for peptide macrocyclization.
P450 enzymes are highly effective catalysts, yet little research has been conducted on their ability to modify ribosomal peptides. Now uncharted bacterial cytochrome P450s responsible for the macrocyclization of ribosomal peptides have been discovered by sequence‐ and 3D‐structure‐based genome mining. These P450s exhibit diverse catalytic capabilities, catalyzing aromatic crosslinking by forming C−C, C−N, and C−O bonds.
The polycomb group protein B lymphoma Mo-MLV insertion region 1 homolog (Bmi-1) is dysregulated in various cancers, and its upregulation strongly correlates with an invasive phenotype and poor ...prognosis in patients with nasopharyngeal carcinomas. However, the underlying mechanism of Bmi-1-mediated invasiveness remains unknown. In the current study, we found that upregulation of Bmi-1 induced epithelial-mesenchymal transition (EMT) and enhanced the motility and invasiveness of human nasopharyngeal epithelial cells, whereas silencing endogenous Bmi-1 expression reversed EMT and reduced motility. Furthermore, upregulation of Bmi-1 led to the stabilization of Snail, a transcriptional repressor associated with EMT, via modulation of PI3K/Akt/GSK-3beta signaling. Chromatin immunoprecipitation assays revealed that Bmi-1 transcriptionally downregulated expression of the tumor suppressor PTEN in tumor cells through direct association with the PTEN locus. This in vitro analysis was consistent with the statistical inverse correlation detected between Bmi-1 and PTEN expression in a cohort of human nasopharyngeal carcinoma biopsies. Moreover, ablation of PTEN expression partially rescued the migratory/invasive phenotype of Bmi-1-silenced cells, indicating that PTEN might be a major mediator of Bmi-1-induced EMT. Our results provide functional and mechanistic links between the oncoprotein Bmi-1 and the tumor suppressor PTEN in the development and progression of cancer.
Metabolic reprogramming plays important roles in development and progression of nasopharyngeal carcinoma (NPC), but the underlying mechanism has not been completely defined. In this work, we found ...INSL5 was elevated in NPC tumor tissue and the plasma of NPC patients. Plasma INSL5 could serve as a novel diagnostic marker for NPC, especially for serum VCA‐IgA‐negative patients. Moreover, higher plasma INSL5 level was associated with poor disease outcome. Functionally, INSL5 overexpression increased, whereas knockdown of its receptor GPCR142 or inhibition of INSL5 reduced cell proliferation, colony formation, and cell invasion in vitro and tumorigenicity in vivo. Mechanistically, INSL5 enhanced phosphorylation and nuclear translocation of STAT5 and promoted glycolytic gene expression, leading to induced glycolysis in cancer cells. Pharmaceutical inhibition of glycolysis by 2‐DG or blockade of INSL5 by a neutralizing antibody reversed INSL5‐induced proliferation and invasion, indicating that INSL5 can be a potential therapeutic target in NPC. In conclusion, INSL5 enhances NPC progression by regulating cancer cell metabolic reprogramming and is a potential diagnostic and prognostic marker as well as a therapeutic target for NPC.
Synopsis
This study reveals that INSL5 promotes tumor progression by regulating cancer cell metabolic reprogramming. INSL5 is a potential diagnostic and prognostic marker as well as a therapeutic target for nasopharyngeal carcinoma (NPC).
INSL5 expression levels are elevated in NPC tumor tissue and in the plasma of NPC patients.
INSL5 plasma levels are associated with NPC patient outcome.
INSL5 promotes tumor progression through an autocrine mechanism involving binding to its receptor GPCR142.
INSL5 activates JAK1‐STAT5 signal pathway and promotes glycolytic gene expression, which in turn induces metabolic reprogramming in cancer cells.
INSL5‐GPCR142 axis can be a potential therapeutic target for NPC.
This study reveals that INSL5 promotes tumor progression by regulating cancer cell metabolic reprogramming. INSL5 is a potential diagnostic and prognostic marker as well as a therapeutic target for nasopharyngeal carcinoma (NPC).
Although early detection and systemic therapies have improved the diagnosis and clinical cure rate of breast cancer, breast cancer remains the most frequently occurring malignant cancer in women due ...to a lack of sufficiently effective treatments. Thus, to develop potential targeted therapies and thus benefit more patients, it is helpful to understand how cancer cells work. ZIC family members have been shown to play important roles in neural development and carcinogenesis. In our study, we found that ZIC2 is downregulated in breast cancer tissues at both the mRNA and protein levels. Low expression of ZIC2 was correlated with poor outcome in breast cancer patients and serves as an independent prognostic marker. Furthermore, overexpression of ZIC2 repressed, whereas knockdown of ZIC2 promoted, cell proliferation and colony formation ability in vitro and tumor growth in vivo. Using ChIP‐seq and RNA‐seq analysis, we screened and identified STAT3 as a potential target for ZIC2. ZIC2 bound to the STAT3 promoter and repressed the promoter activities of STAT3. ZIC2 knockdown induced the expression of STAT3, increasing the level of phosphorylated STAT3. These results suggest that ZIC2 regulates the transcription of STAT3 by directly binding to the STAT3 promoter. Additionally, interfering STAT3 with siRNAs or inhibitors abrogated the oncogenic effects induced by decreased ZIC2. Taken together, our results indicate that ZIC2 serves as a useful prognostic marker in breast cancer and acts as a tumor suppressor by regulating STAT3, implying that STAT3 inhibitors might provide an alternative treatment option for breast cancer patients with ZIC2 downregulation.
What's new?
ZIC family members regulate neural development but have also been implicated in the development of various tumors. Here the authors report downregulation of ZIC2 in breast cancer cells. Low expression of ZIC2 correlated with poor outcome in breast cancer patients and served as an independent prognostic marker. The transcription factor STAT3 was identified as a potential target for ZIC2, and inhibition of STAT3 abrogated the oncogenic effects induced by decreased ZIC2 expression. STAT3 inhibitors might provide an alternative option for women with breast cancer showing ZIC2 downregulation.
It has been recently reported that a side population of cells in nasopharyngeal carcinoma (NPC) displayed characteristics of stem-like cancer cells. However, the molecular mechanisms underlying the ...modulation of such stem-like cell populations in NPC remain unclear. Epstein-Barr virus was the first identified human tumor virus to be associated with various malignancies, most notably NPC. LMP2A, the Epstein-Barr virus encoded latent protein, has been reported to play roles in oncogenic processes. We report by immunostaining in our current study that LMP2A is overexpressed in 57.6% of the nasopharyngeal carcinoma tumors sampled and is mainly localized at the tumor invasive front. We found also in NPC cells that the exogenous expression of LMP2A greatly increases their invasive/migratory ability, induces epithelial-mesenchymal transition (EMT)-like cellular marker alterations, and stimulates stem cell side populations and the expression of stem cell markers. In addition, LMP2A enhances the transforming ability of cancer cells in both colony formation and soft agar assays, as well as the self-renewal ability of stem-like cancer cells in a spherical culture assay. Additionally, LMP2A increases the number of cancer initiating cells in a xenograft tumor formation assay. More importantly, the endogenous expression of LMP2A positively correlates with the expression of ABCG2 in NPC samples. Finally, we demonstrate that Akt inhibitor (V) greatly decreases the size of the stem cell side populations in LMP2A-expressing cells. Taken together, our data indicate that LMP2A induces EMT and stem-like cell self-renewal in NPC, suggesting a novel mechanism by which Epstein-Barr virus induces the initiation, metastasis and recurrence of NPC.
American ginseng (Panax quinquefolius L.) is an herbal medicine with polysaccharides as its important active ingredient. The purpose of this research was to identify the effects of the ...polysaccharides of P. quinquefolius (WQP) on rats with antibiotic-associated diarrhoea (AAD) induced by lincomycin hydrochloride. WQP was primarily composed of galacturonic acid, glucose, galactose, and arabinose. The yield, total sugar content, uronic acid content, and protein content were 6.71%, 85.2%, 31.9%, and 2.1%, respectively. WQP reduced the infiltration of inflammatory cells into the ileum and colon, reduced the IL-1β, IL-6, IL-17A, and TNF-α levels, increased the levels of IL-4 and IL-10 in colon tissues, improved the production of acetate and propionate, regulated the gut microbiota diversity and composition, improved the relative richness of Lactobacillus and Bacteroides, and reduced the relative richness of Blautia and Coprococcus. The results indicated that WQP can enhance the recovery of the intestinal structure in rats, reduce inflammatory cytokine levels, improve short-chain fatty acid (SCFA) levels, promote recovery of the gut microbiota and intestinal mucosal barrier, and alleviate antibiotic-related side effects such as diarrhoea and microbiota dysbiosis caused by lincomycin hydrochloride. We found that WQP can protect the intestinal barrier by increasing Occludin and Claudin-1 expression. In addition, WQP inhibited the MAPK inflammatory signaling pathway to improve the inflammatory status. This study provides a foundation for the treatment of natural polysaccharides to reduce antibiotic-related side effects.
The effects of tamoxifen on mouse behavior Li, Xin; Du, Zhuo‐Jun; Chen, Man‐Qi ...
Genes, brain and behavior,
April 2020, 2020-04-00, 20200401, Letnik:
19, Številka:
4
Journal Article
Recenzirano
Odprti dostop
The CreERT2 recombinase system is an advanced method to temporally control site‐specific mutagenesis in adult rodents. In this process, tamoxifen is injected to induce Cre recombinase expression, and ...then, Cre recombinase can excise LoxP‐flanked DNA. However, tamoxifen is a nonselective estrogen receptor antagonist that may influence behavioral alterations. Therefore, we designed five different protocols (acute effects, chronic effects, chronic effects after social defeat model, chronic effects after learned helplessness model, chronic effects after isolation models) to explore whether tamoxifen affects mouse behavior. Researching the acute/chronic effects of tamoxifen, we found that tamoxifen could influence locomotor activity, anxiety and immobility time in the forced swimming test. Researching the chronic effects of tamoxifen after social defeat/learned helplessness/isolation models, we found that tamoxifen could also influence locomotor activity, social interaction and anxiety. Therefore, the effects of tamoxifen are more complex than previously reported. Our results show, for the first time, that tamoxifen affects behavior in mouse models. Meanwhile, we compare the effects of tamoxifen in different protocols. These results will provide important information when designing similar experiments.
First, in gene editing research, tamoxifen is injected to induce Cre expression in the CreERT2 recombinase system. Tamoxifen is a nonselective estrogen receptor antagonist. We find the effects of tamoxifen are more complex than previously reported. The effects of mutagenesis might be concealed by the effects of tamoxifen in many behavior tests. Second, our results show, for the first time, that tamoxifen affects behavior in mouse models and we compare the effects of tamoxifen in different protocols. These results will provide important information when designing similar experiments.
B-lymphoma Moloney murine leukemia virus insertion region-1 (Bmi-1) acts as an oncogene in various tumors, and its overexpression correlates with a poor outcome in several human cancers. Ectopic ...expression of Bmi-1 can induce epithelial-mesenchymal transition (EMT) and enhance the motility and invasiveness of human nasopharyngeal epithelial cells (NPECs), whereas silencing endogenous Bmi-1 expression can reverse EMT and reduce the metastatic potential of nasopharyngeal cancer cells (NPCs). Mouse xenograft studies indicate that coexpression of Bmi-1 and H-Ras in breast cancer cells can induce an aggressive and metastatic phenotype with an unusual occurrence of brain metastasis; although, Bmi-1 overexpression did not result in oncogenic transformation of MCF-10A cells. However, the underlying molecular mechanism of Bmi-1-mediated progression and the metastasis of breast cancer are not fully elucidated at this time.
Bmi-1 expression is more pronouncedly increased in primary cancer tissues compared to matched adjacent non-cancerous tissues. High Bmi-1 expression is correlated with advanced clinicopathologic classifications (T, N, and M) and clinical stages. Furthermore, a high level of Bmi-1 indicates an unfavorable overall survival and serves as a high risk marker for breast cancer. In addition, inverse transcriptional expression levels of Bmi-1 and E-cadherin are detected between the primary cancer tissues and the matched adjacent non-cancerous tissues. Higher Bmi-1 levels are found in the cancer tissue, whereas the paired adjacent non-cancer tissue shows higher E-cadherin levels. Overexpression of Bmi-1 increases the motility and invasive properties of immortalized human mammary epithelial cells, which is concurrent with the increased expression of mesenchymal markers, the decreased expression of epithelial markers, the stabilization of Snail and the dysregulation of the Akt/GSK3β pathway. Consistent with these observations, the repression of Bmi-1 in highly metastatic breast cancer cells remarkably reduces cellular motility, invasion and transformation, as well as tumorigenesis and lung metastases in nude mice. In addition, the repression of Bmi-1 reverses the expression of EMT markers and inhibits the Akt/GSK3β/Snail pathway.
This study demonstrates that Bmi-1 promotes the invasion and metastasis of human breast cancer and predicts poor survival.
Food for special medical purposes (FSMP) has received increasing attention as an enteral nutritional supplement. To investigate the effects of whole nutritional formula (WNF) containing dietary fiber ...and regular formula on nutritional supplementation and improvement of intestinal microecology, a rat malnutrition model was established with the formulations of WNF, FOS, and SDF (10, 20 g/kg bw) administered by gavage for 30 days. The results showed that the three formulations effectively improved the nutritional status of the malnourished rats, significantly increasing the level of IgG, increasing the abundance of Bacteroidetes, and affecting the content of propionic acid (PRO). The nutritional status of rats is closely related to growth performance, nutritional indexes, and immunoglobulin index, which cause changes in the composition of the intestinal flora. The above results showed that WNF positively affected the nutritional improvement, immune level, and intestinal health of rats. The comprehensive evaluation also suggested that the formulation containing ginseng water‐soluble dietary fiber (ginseng‐SDF) had the most significant effect.
WNF foods improve the nutritional and immune factors level of malnourished rats. WNF foods has positive regulatory effect on SCFA and intestinal flora. WNF foods containing ginseng SDF have better improvement effect.
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•Cucurbitacin E induces apoptosis and attenuates activation of hepatic stellate cells.•Cucurbitacin E alleviated thioacetamide-induced hepatic fibrosis.•Cucurbitacin E regulates ...Akt-AMPK-mTOR signaling pathway.
The study evaluated the potential protective effect and underlying mechanism of Cucurbitacin E (CuE) in both thioacetamide-induced hepatic fibrosis and activated HSCs. CuE inhibited the proliferation of activated HSC/T-6 cells in a concentration- and time-dependent manner; triggered the activation of caspase-3, cleaved PARP, altered ratio of bcl-2-to-bax, and affected cytochrome C protein in a time- and concentration-dependent manner. CuE arrested activated HSCs at the G2/M phase. Furthermore, CuE reduced levels of p-Erk/MAPK and also inhibited the protein and mRNA expressions of α-SMA, TIMP-1 and collagen I in activated HSC-T6 cells. CuE inhibited PI3K and Akt phosphorylation, and reduced the levels of p-mTOR and p-P70S6K and increased the expression of p-AMPK, which is similar with AICAR and metformin. C57BL/6 mice were intraperitoneally injected with thioacetamide (TAA) for five continuous weeks (100 or 200mg/kg, three times per week) along with daily administration of CuE (5 or 10mg/kg/d) and curcumin (Cur, 20mg/kg). CuE treatments significantly reduced serum ALT/AST levels, α-SMA, TIMP-1, and collagen I protein expressions. HE, Masson trichrome, Sirius red and immunohistochemical staining also suggested that CuE could ameliorate hepatic fibrosis. Our findings suggest that CuE induces apoptosis of activated HSC and ameliorates TAA-induced hepatic fibrosis through activation of AMPK and blocking mTOR-dependent signaling pathway.
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