Lysyl Oxidase 3 Is a Dual-Specificity Enzyme Involved in STAT3 Deacetylation and Deacetylimination Modulation.

In mammalian cells, histone deacetylase (HDAC) and Sirtuin (SIRT) are two families responsible for removing acetyl groups from acetylated proteins. Here, we describe protein deacetylation coupled with deacetylimination as a function of lysyl oxidase (LOX) family members. LOX-like 3 (Loxl3) associates with Stat3 in the nucleus to deacetylate and deacetyliminate Stat3 on multiple acetyl-lysine sites. Surprisingly, Loxl3 N-terminal scavenger receptor cysteine-rich (SRCR) repeats, rather than the C-terminal oxidase catalytic domain, represent the major deacetylase/deacetyliminase activity. Loxl3-mediated deacetylation/deacetylimination disrupts Stat3 dimerization, abolishes Stat3 transcription activity, and restricts cell proliferation. In Loxl3-/- mice, Stat3 is constitutively acetylated and naive CD4+ T cells are potentiated in Th17/Treg cell differentiation. When overexpressed, the SRCR repeats from other LOX family members can catalyze protein deacetylation/deacetylimination. Thus, our findings delineate a hitherto-unknown mechanism of protein deacetylation and deacetylimination catalyzed by lysyl oxidases.

UBXN9 inhibits the RNA exosome function to promote T cell control of liver tumorigenesis.

BACKGROUND AND AIMS: Liver tumorigenesis encompasses oncogenic activation and self-adaptation of various biological processes in premalignant hepatocytes to circumvent the pressure of cellular stress and host immune control. Ubiquitin regulatory X domain-containing proteins (UBXNs) participate in the regulation of certain signaling pathways. However, whether UBXN proteins function in the development of liver cancer remains unclear. APPROACH AND RESULTS: Here, we demonstrated that UBXN9 (Alveolar Soft Part Sarcoma Chromosomal Region Candidate Gene 1 Protein/Alveolar Soft Part Sarcoma Locus) expression was decreased in autochthonous oncogene-induced mouse liver tumors and ~47.7% of human HCCs, and associated with poor prognosis in patients with HCC. UBXN9 attenuated liver tumorigenesis induced by different oncogenic factors and tumor growth of transplanted liver tumor cells in immuno-competent mice. Mechanistically, UBXN9 significantly inhibited the function of the RNA exosome, resulting in increased expression of RLR-stimulatory RNAs and activation of the retinoic acid-inducible gene-I-IFN-Ι signaling in tumor cells, and hence potentiated T cell recruitment and immune control of tumor growth. Abrogation of the CD8 + T cell response or inhibition of tumor cell retinoic acid-inducible gene-I signaling efficiently counteracted the UBXN9-mediated suppression of liver tumor growth. CONCLUSIONS: Our results reveal a modality in which UBXN9 promotes the stimulatory RNA-induced retinoic acid-inducible gene-I-interferon signaling that induces anti-tumor T cell response in liver tumorigenesis. Targeted manipulation of the UBXN9-RNA exosome circuit may have the potential to reinstate the immune control of liver tumor growth.

STAT4 activation by leukemia inhibitory factor confers a therapeutic effect on intestinal inflammation.

T helper 17 (Th17)-cell differentiation triggered by interleukin-6 (IL-6) via STAT3 activation promotes inflammation in inflammatory bowel disease (IBD) patients. However, leukemia inhibitory factor (LIF), an IL-6 family cytokine, restricts inflammation by blocking Th17-cell differentiation via an unknown mechanism. Here, we report that microbiota dysregulation promotes LIF secretion by intestinal epithelial cells (IECs) in a mouse colitis model. LIF greatly activates STAT4 phosphorylation on multiple SPXX elements within the C-terminal transcription regulation domain. STAT4 and STAT3 act reciprocally on both canonical cis-inducible elements (SIEs) and noncanonical "AGG" elements at different loci. In lamina propria lymphocytes (LPLs), STAT4 activation by LIF blocks STAT3-dependent Il17a/Il17f promoter activation, whereas in IECs, LIF bypasses the extraordinarily low level of STAT4 to induce YAP gene expression via STAT3 activation. In addition, we found that the administration of LIF is sufficient to restore microbiome homeostasis. Thus, LIF effectively inhibits Th17 accumulation and promotes repair of damaged intestinal epithelium in inflamed colon, serves as a potential therapy for IBD.

PBX1 promotes development of natural killer cells by binding directly to the Nfil3 promoter.

The transcription factor nuclear factor interleukin-3-regulated protein (NFIL3, also called E4BP4) is crucial for commitment of natural killer (NK) cells from common lymphoid progenitors (CLPs). However, the identity of the factor that can regulate NFIL3 directly during the NK-cell development is not known. Here, we reveal that pre-B-cell leukemia transcription factor 1 (PBX1) can upregulate the NFIL3 expression directly. We used conditional knockout mice in which PBX1 in hematopoietic cells was specifically absent. The number of NK-committed progenitor pre-NKP cells and rNKP cells was reduced significantly in the absence of PBX1, which was consistent with NFIL3 deficiency. Also, the NFIL3 expression in NK cells was decreased if PBX1 was absent. We demonstrated that PBX1 was bound directly to the promoter of Nfil3 and facilitated transcription. Upon knockout of the binding site of PBX1 in the Nfil3 promoter, mice showed fewer NK-precursor cells and NK cells, just like that observed in Nfil3 knockout mice. Furthermore, asparagine N286 in the homeodomain of PBX1 controlled the binding of PBX1 to the Nfil3 promoter. Collectively, these findings demonstrate that the transcription factor PBX1 promotes the early development of NK cells by upregulating the Nfil3 expression directly.

A neural network potential energy surface for the F + H2O ↔ HF + OH reaction and quantum dynamics study of the isotopic effect.

A global potential energy surface for the F + H2O ↔ HF + OH reaction has been constructed using the neural network method based on ∼24 000 ab initio energies calculated at the all-electron CCSD(T)-F12a/cc-pCVTZ-F12 level of theory. The correction term accounting for the influence of spin-orbit couplings has also been included with a hierarchical scheme. The isotopic effect on the total reaction probabilities of the reaction was investigated using the time-dependent wave packet method.

Full-dimensional quantum dynamics study of isotope effects for the H2 + NH2/ND2/NHD and H2/D2/HD + NH2 reactions.

A full-dimensional quantum dynamical study for the bimolecular reactions of hydrogen molecules with amino radicals for different isotopologues is reported. The nonreactive amino radical is described by two Radau vectors that are very close to the valence bond coordinates. Potential-optimized discrete variable representation basis is used for the vibrational coordinates of the amino radical. Starting from the reaction H2 + NH2, we study the isotope effects for the two reagents separately, i.e., H2 + NH2/ND2/NHD and H2/D2/HD + NH2. The effects of different vibrational mode excitations of the reagents on the reactivities are studied. Physical explanations about the isotope effects are also provided thoroughly including the influence of vibrational energy differences between the different isotopologues and the impact of the tunneling effect.

A pilot study of new promising non-coding RNA diagnostic biomarkers for early-stage colorectal cancers.

Background Diagnostic biomarkers for the detection of colorectal cancers (CRCs) are lacking. Recent studies have demonstrated that circulating long non-coding RNAs have the potential to serve as biomarkers for the detection of cancers. We analyzed the significance of lncRNAs 91H, PVT-1 and MEG3 in the detection of CRC. Methods We examined the expression levels of 13 candidate lncRNAs in the plasma of 18 CRC patients and 20 non-cancerous controls. Then, we validated our findings by determining the expression levels of six promising lncRNAs in CRC tissues and normal colorectal tissues. Finally, we evaluated the clinical relevance of lncRNAs 91H, PVT-1 and MEG3 in the plasma of 58 CRC patients and 56 non-cancerous controls. Results Our data revealed that the expression levels of lncRNAs 91H, PVT-1 and MEG3 were significantly higher in plasma samples from CRC patients than in those from non-cancerous controls. The combination of 91H, PVT-1 and MEG3 could discriminate CRC patients from non-cancerous controls with an area under the receiver-operating curve (AUC) of 0.877 at a cut-off value of 0.3816, with a sensitivity of 82.76% and 78.57% specificity. More importantly, the combination of lncRNAs shows more sensitivity in the detection of early-stage CRC than the combination of CEA and CA19-9, biomarkers currently used for CRC detection (p < 0.0001). Conclusions lncRNAs 91H, PVT-1 and MEG3 are promising diagnostic biomarkers for early-stage CRC.

Bcl-3 promotes proliferation and chemosensitivity in BL1 subtype of TNBC cells.

Bcl-3 is an established oncogene in diverse malignant tumors. In this study, we investigated a dual role of Bcl-3 in BL1-subtype triple-negative breast cancer (TNBC). The BL1-subtype TNBC is featured by increasing cell cycle gene expression and the highest sensitivity to chemotherapy among all subtypes. Bcl-3 is associated with a better prognosis in BL1 patients. Bcl-3 knockdown in BL1 cell MDA-MB-468 induces the inhibition of cell proliferation and the G1/S transition arrest by promoting p27 and reducing the expressions of c-Myc and skp2 at mRNA and protein levels. Meanwhile, Bcl-3 enhances the sensitivity of MDA-MB-468 to chemotherapeutics ABX and PTX. Furthermore, the regulation mechanisms are restricted to BL1 cell and do not occur in SUM159PT, a typical MSL subtype of TNBC cell. These data suggest that Bcl-3 may be a potential clinical biomarker for diagnosis, treatment, and prognosis of patients with BL1-subtype TNBC.

Heterologous expression, purification and function of the extracellular domain of human RANK.

BACKGROUND: Receptor activator of NF-κB ligand (RANKL)/RANK signaling essentially functions within the skeletal system, particularly participating in osteoclastogenesis and bone resorption. In addition, this signaling pathway has also been shown to influence tumor progression as well as the development and function of the immune system. Therefore, blocking the interaction between RANKL and RANK is a new therapeutic approach to prevent bone-related diseases and cancer. RESULTS: The coding sequence encoding the extracellular domain of human RANK (RANK-N) was codon optimized for Pichia pastoris and cloned into the pPIC9K vector, and the recombinant plasmid was then transformed into P. pastoris. The expression of RANK-N protein was confirmed using SDS-PAGE with Coomassie Brilliant Blue stain and western blotting. Recombinant RANK-N protein was purified by a multistep process including ultrafiltration (UF), Sephadex G-50 size-exclusion chromatography and Q-Sepharose Fast Flow ion exchange chromatography, which resulted in a purity >95%. We found that the RANK-N protein can block RANKL-RANK signaling both in vitro and in vivo. Furthermore, using a patient-derived xenograft of human colon cancer, we found that the recombinant RANK-N protein can inhibit the growth of colorectal cancer. CONCLUSIONS: The results show that a simple system to express and purify functional RANK-N protein has been developed. This work has thus laid a foundation for further research and clinical applications of RANK-N protein in treating bone-related diseases or even colorectal cancer.

Expression, purification and biological characterization of the extracellular domain of CD40 from Pichia pastoris.

BACKGROUND: CD40, also called Bp50, is a novel member of the TNF receptor superfamily. Based on its important role in multiple physiological and pathological processes, the CD40 signaling pathway has become a vital target for treating transplantation, autoimmune diseases and cancers. This study generated a protein fragment that disrupts this signaling pathway. RESULTS: A DNA fragment encoding the extracellular domain of CD40 (CD40-N) has been codon-optimized and cloned into pPIC9K to create a Pichia pastoris expression and secretion strain. SDS-PAGE and Western blotting assays using the culture media from methanol-induced expression strains showed that recombinant CD40-N, a 27 kDa glycosylated protein, was secreted into the culture broth. The recombinant protein was purified to more than 90 % using Sephadex G-50 size-exclusion chromatography and Q Sepharose Fast Flow ion exchange. Finally, 120 mg of the protein was obtained at a relatively high purity from 3 l supernatant. Binding assay (ITC200 assay) shown the direct interaction of CD40-N and CD40 agonist antibody (G28-5). The bioactivity of recombinant CD40-N was confirmed by its ability to disrupt non-canonical NF-κB signaling activated by CD40 agonist antibody or CD40 ligand and to inhibit ant-CD40 agonist antibody-induced TNF-alpha expression in BJAB cells in vitro. In addition, our data indicate that the protein has curative potential in treating dextran sulfate sodium (DSS)-induced colitis in vivo. CONCLUSIONS: The results show that the experimental procedure we have developed using P. pastoris can be used to produce large amounts of active CD40-N for research and industrial purposes. The protein fragment we have acquired has potential to be used in research or even treating inflammation diseases such as colitis.

Cbx4 regulates the proliferation of thymic epithelial cells and thymus function.

Thymic epithelial cells (TECs) are the main component of the thymic stroma, which supports T-cell proliferation and repertoire selection. Here, we demonstrate that Cbx4, a Polycomb protein that is highly expressed in the thymic epithelium, has an essential and non-redundant role in thymic organogenesis. Targeted disruption of Cbx4 causes severe hypoplasia of the fetal thymus as a result of reduced thymocyte proliferation. Cell-specific deletion of Cbx4 shows that the compromised thymopoiesis is rooted in a defective epithelial compartment. Cbx4-deficient TECs exhibit impaired proliferative capacity, and the limited thymic epithelial architecture quickly deteriorates in postnatal mutant mice, leading to an almost complete blockade of T-cell development shortly after birth and markedly reduced peripheral T-cell populations in adult mice. Furthermore, we show that Cbx4 physically interacts and functionally correlates with p63, which is a transcriptional regulator that is proposed to be important for the maintenance of the stemness of epithelial progenitors. Together, these data establish Cbx4 as a crucial regulator for the generation and maintenance of the thymic epithelium and, hence, for thymocyte development.

A microRNA 221- and 222-mediated feedback loop maintains constitutive activation of NFκB and STAT3 in colorectal cancer cells.

BACKGROUND & AIMS: Constitutive activation of the transcription factors nuclear factor κB (NF-κB) and STAT3 is involved in the development and progression of human colorectal cancer (CRC). Little is known about how these factors become activated in cancer cells. We investigated whether microRNA miR-221 and miR-222 regulate NF-κB and signal transducer and activator of transcription 3 (STAT3) activation in human CRC cell lines. METHODS: CRC cell lines (HCT116 and RKO) were transfected with miR-221 or miR-222 mimics or inhibitors. The activity levels of NF-κB and STAT3 were measured in dual luciferase reporter assays. We used immunoblot and real-time polymerase chain reaction analyses to measure protein and messenger RNA (mRNA) levels. Cells were analyzed by proliferation, viability, and flow cytometry analyses. Mice were given injections of azoxymethane, followed by dextran sodium sulfate, along with control lentivirus or those expressing mRNAs that bind miR-221 and miR-222 (miR-221/miR-222 sponge). The levels of miR-221 and miR-222 as well as RelA, STAT3, and PDLIM2 mRNAs were measured in 57 paired CRC and adjacent nontumor tissues from patients. RESULTS: In CRC cell lines, mimics of miR-221 and miR-222 activated NF-κB and STAT3, further increasing expression of miR-221 and miR-222. miR-221 and miR-222 bound directly to the coding region of RelA mRNA, increasing its stability. miR-221 and miR-222 also reduced the ubiquitination and degradation of the RelA and STAT3 proteins by binding to the 3' untranslated region of PDLIM2 mRNA (PDLIM2 is a nuclear ubiquitin E3 ligase for RelA and STAT3). Incubation of CRC cells with miR-221 and miR-222 inhibitors reduced their proliferation and colony formation compared with control cells. In mice with colitis, injection of lentiviruses expressing miR-221/miR-222 sponges led to formation of fewer tumors than injection of control lentiviruses. Human CRC tissues had higher levels of miR-221 and miR-222 than nontumor colon tissues; increases correlated with increased levels of RelA and STAT3 mRNAs. Levels of PDLIM2 mRNA were lower in CRC than nontumor tissues. CONCLUSIONS: In human CRC cells, miR-221 and miR-222 act in a positive feedback loop to increase expression levels of RelA and STAT3. Antagonism of miR-221 and miR-222 reduces growth of colon tumors in mice with colitis.

An osteopontin-integrin interaction plays a critical role in directing adipogenesis and osteogenesis by mesenchymal stem cells.

An imbalance between normal adipogenesis and osteogenesis by mesenchymal stem cells (MSCs) has been shown to be related to various human metabolic diseases, such as obesity and osteoporosis; however, the underlying mechanisms remain elusive. We found that the interaction between osteopontin (OPN), an arginine-glycine-aspartate-containing glycoprotein, and integrin αv/ß1 plays a critical role in the lineage determination of MSCs. Although OPN is a well-established marker during osteogenesis, its role in MSC differentiation is still unknown. Our study reveals that blockade of OPN function promoted robust adipogenic differentiation, while inhibiting osteogenic differentiation. Re-expression of OPN restored a normal balance between adipogenesis and osteogenesis in OPN(-/-) MSCs. Retarded bone formation by OPN(-/-) MSCs was also verified by in vivo implantation with hydroxyapatite-tricalcium phosphate, a bone-forming matrix. The role of extracellular OPN in MSC differentiation was further demonstrated by supplementation and neutralization of OPN. Blocking well-known OPN receptors integrin αv/ß1 but not CD44 also affected MSC differentiation. Further studies revealed that OPN inhibits the C/EBPs signaling pathway through integrin αv/ß1. Consistent with these in vitro results, OPN(-/-) mice had a higher fat to total body weight ratio than did wild-type mice. Therefore, our study demonstrates a novel role for OPN-integrin αv/ß1 in regulating MSC differentiation.

The tumor promoter and NF-κB modulator Bcl-3 regulates splenic B cell development.

Bcl-3 is an atypical member of the family of IκB proteins. Unlike the classic members, Bcl-3 functions as a nuclear transcriptional cofactor that may, depending on context, promote or suppress genes via association with p50/NF-κB1 or p52/NF-κB2 homodimers. Bcl-3 is also an oncogene, because it is a partner in recurrent translocations in B cell tumors, resulting in deregulated expression. Bcl-3 functions, however, remain poorly understood. We have investigated the role of Bcl-3 in B cells and discovered a previously unknown involvement in the splenic development of these cells. Loss of Bcl-3 in B cells resulted in significantly more marginal zone (MZ) and fewer follicular (FO) B cells. Conversely, transgenic expression of Bcl-3 in B cells generated fewer MZ and more FO B cells. Both Bcl-3(-/-) FO and MZ B cells were more responsive to LPS stimulation compared with their wild-type counterparts, including increased proliferation. By contrast, Bcl-3(-/-) FO B cells were more prone to apoptosis upon BCR stimulation, also limiting their expansion. The data reveal Bcl-3 as a regulator of B cell fate determination, restricting the MZ path and favoring the FO pathway, at least in part, via increased signal-specific survival of the latter, a finding of relevance to its tumorigenic activity.

Syndecan-1 inhibition promotes antitumor immune response and facilitates the efficacy of anti-PD1 checkpoint immunotherapy.

Tumor cell-originated events prevent efficient antitumor immune response and limit the application of anti-PD1 checkpoint immunotherapy. We show that syndecan-1 (SDC1) has a critical role in the regulation of T cell-mediated control of tumor growth. SDC1 inhibition increases the permeation of CD8+ T cells into tumors and triggers CD8+ T cell-mediated control of tumor growth, accompanied by increased proportions of progenitor-exhausted and effector-like CD8+ T cells. SDC1 deficiency alters multiple signaling events in tumor cells, including enhanced IFN-γ-STAT1 signaling, and augments antigen presentation and sensitivity to T cell-mediated cytotoxicity. Combinatory inhibition of SDC1 markedly potentiates the therapeutic effects of anti-PD1 in inhibiting tumor growth. Consistently, the findings are supported by the data from human tumors showing that SDC1 expression negatively correlates with T cell presence in tumor tissues and the response to immune checkpoint blockade therapy. Our findings suggest that SDC1 inhibits antitumor immunity, and that targeting SDC1 may promote anti-PD1 response for cancer treatment.

Feshbach resonances in the F + CHD3 → HF + CD3 reaction.

The signature of dynamics resonances was observed in the benchmark polyatomic F + CH4/CHD3 reactions more than a decade ago; however, the dynamical origin of the resonances is still not clear due to the lack of reliable quantum dynamics studies on accurate potential energy surfaces. Here, we report a six-dimensional state-to-state quantum dynamics study on the F + CHD3 → HF + CD3 reaction on a highly accurate potential energy surface. Pronounced oscillatory structures are observed in the total and product rovibrational-state-resolved reaction probabilities. Detailed analysis reveals that these oscillating features originate from the Feshbach resonance states trapped in the peculiar well on the HF(v' = 3)-CD3 vibrationally adiabatic potential caused by HF chemical bond softening. Most of the resonance structures on the reaction probabilities are washed out in the well converged integral cross sections (ICS), leaving only one distinct peak at low collision energy. The calculated HF vibrational state-resolved ICS for CD3(v = 0) agrees quantitatively with the experimental results, especially the branching ratio, but the theoretical CD3 umbrella vibration state distribution is found to be much hotter than the experiment.

B-cell-derived IL-10 promotes allergic sensitization in asthma regulated by Bcl-3.

Aeroallergen sensitization, mainly mediated by lung epithelium and dendritic cells (DCs), is integral to allergic asthma pathogenesis and progression. IL-10 has a dual role in immune responses, as it inhibits myeloid cell activation but promotes B-cell responses and epithelial cell proliferation. Here, we report a proinflammatory function of B-cell-derived IL-10 modulated by Bcl-3 in allergic asthma. Specifically, Bcl-3-/- mice showed elevated IL-10 levels and were found to be highly vulnerable to allergic asthma induced by house dust mites (HDMs). IL-10 had a positive correlation with the levels of the DC chemoattractant CCL-20 in HDM-sensitized mice and in patients with asthma and induced a selective increase in CCL-20 production by mouse lung epithelial cells. Blockade of IL-10 or IL-10 receptors during sensitization dampened both HDM-induced sensitization and asthma development. IL-10 levels peaked 4 h post sensitization with HDM and IL-10 was primarily produced by B cells under Bcl-3-Blimp-1-Bcl-6 regulation. Mice lacking B-cell-derived IL-10 displayed decreased lung epithelial CCL-20 production and diminished DC recruitment to the lungs upon HDM sensitization, thereby demonstrating resistance to HDM-induced asthma. Moreover, responses to HDM stimulation in Bcl-3-/- mice lacking B-cell-derived IL-10 were comparable to those in Bcl-3+/+ mice. The results revealed an unexpected role of B-cell-derived IL-10 in promoting allergic sensitization and demonstrated that Bcl-3 prevents HDM-induced asthma by inhibiting B-cell-derived IL-10 production. Thus, targeting the Bcl-3/IL-10 axis to inhibit allergic sensitization is a promising approach for treating allergic asthma. IL-10 is released rapidly from lung plasma cells under Bcl-3-Blimp-1-Bcl-6 regulation upon house dust mite exposure and amplifies lung epithelial cell (EC)-derived CCL-20 production and subsequent dendritic cell (DC) recruitment to promote allergic sensitization in asthma.

B cell-derived IL-10 promotes the resolution of lipopolysaccharide-induced acute lung injury.

Inflammation resolution is critical for acute lung injury (ALI) recovery. Interleukin (IL)-10 is a potent anti-inflammatory factor. However, its role in ALI resolution remains unclear. We investigated the effects of IL-10 during the ALI resolution process in a murine lipopolysaccharide (LPS)-induced ALI model. Blockade of IL-10 signaling aggravates LPS-induced lung injury, as manifested by elevated pro-inflammatory factors production and increased neutrophils recruitment to the lung. Thereafter, we used IL-10 GFP reporter mice to discern the source cell of IL-10 during ALI. We found that IL-10 is predominantly generated by B cells during the ALI recovery process. Furthermore, we used IL-10-specific loss in B-cell mice to elucidate the effect of B-cell-derived IL-10 on the ALI resolution process. IL-10-specific loss in B cells leads to increased pro-inflammatory cytokine expression, persistent leukocyte infiltration, and prolonged alveolar barrier damage. Mechanistically, B cell-derived IL-10 inhibits the activation and recruitment of macrophages and downregulates the production of chemokine KC that recruits neutrophils to the lung. Moreover, we found that IL-10 deletion in B cells leads to alterations in the cGMP-PKG signaling pathway. In addition, an exogenous supply of IL-10 promotes recovery from LPS-induced ALI, and IL-10-secreting B cells are present in sepsis-related ARDS. This study highlights that B cell-derived IL-10 is critical for the resolution of LPS-induced ALI and may serve as a potential therapeutic target.

LncGMDS-AS1 promotes the tumorigenesis of colorectal cancer through HuR-STAT3/Wnt axis.

Chronic inflammation promotes the tumorigenesis and cell stemness maintenance of colorectal cancer (CRC). However, the bridge role of long noncoding RNA (lncRNA) in linking chronic inflammation to CRC development and progression needs better understanding. Here, we elucidated a novel function of lncRNA GMDS-AS1 in persistently activated signal transducer and transcription activator 3 (STAT3) and Wnt signaling and CRC tumorigenesis. Interleukin-6 (IL-6) and Wnt3a induced lncRNA GMDS-AS1 expression, which was highly expressed in the CRC tissues and plasma of CRC patients. GMDS-AS1 knockdown impaired the survival, proliferation and stem cell-like phenotype acquisition of CRC cells in vitro and in vivo. We performed RNA sequencing (RNA-seq) and mass spectrometry (MS) to probe target proteins and identify their contributions to the downstream signaling pathways of GMDS-AS1. In CRC cells, GMDS-AS1 physically interacted with the RNA-stabilizing protein HuR, thereby protecting the HuR protein from polyubiquitination- and proteasome-dependent degradation. HuR stabilized STAT3 mRNA and upregulated the levels of basal and phosphorylated STAT3 protein, persistently activating STAT3 signaling. Our research revealed that the lncRNA GMDS-AS1 and its direct target HuR constitutively activate STAT3/Wnt signaling and promote CRC tumorigenesis, the GMDS-AS1-HuR-STAT3/Wnt axis is a therapeutic, diagnostic and prognostic target in CRC.

Dynamical Effects of SN2 Reactivity Suppression by Microsolvation: Dynamics Simulations of the F-(H2O) + CH3I Reaction on a 21-Dimensional Potential Energy Surface.

A comparison of atomistic dynamics between microsolvated and unsolvated reactions can expose the precise role of solvent molecules and thus provide deep insight into how solvation influences chemical reactions. Here we developed the first full-dimensional analytical potential energy surface of the F-(H2O) + CH3I reaction, which facilitates the efficient dynamics simulations on a quantitatively accurate level. The computed SN2 reactivity suppression ratio of the monosolvated F-(H2O) + CH3I reaction relative to the unsolvated F- + CH3I reaction as a function of collision energy first increases and then decreases steadily, forming an inverted-V shape, due to the combined dynamical effects of interaction time, steric hindrance, and collision-induced dehydration. Moreover, further analysis reveals that the steric effect of the F-(H2O) + CH3I reaction resulting from the single water molecule is manifested mainly in dragging the F- anion away from the central C atom, rather than shielding F- from C. Our study shows there is great potential in rigorously studying the role of the solvent in more complicated reactions.