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Lili Jiang, Chuyong Lin, Libing Song, Jueheng Wu, Baixue Chen, Zhe Ying, Lishan Fang, Xiao Yan, Mian He, Jun Li, and Mengfeng Li Original citation: J Clin Invest. 2012;122(1):33-47. https://doi.org/10.1172/JCI58849. [...]

Simple Summary: Metastasis, the hallmark of cancer, is accountable for about 90% of cancer-related deaths. Long noncoding RNA (lncRNA), a subset of the noncoding RNAs, has exhibited involvement in various processes, including immune evasion, cell proliferation, migration, and invasion, across multiple human diseases, notably cancer. The objective of our study was to identify a metastasis-associated lncRNA in lung cancer and elucidate the underlying mechanisms. Our findings indicate that Linc01703, which is notably downregulated in metastatic lung cancer cells, effectively suppresses lung cancer metastasis in vivo. Interestingly, Linc01703 does not directly impact the proliferation and invasion capabilities of lung cancer cells but rather inhibits cancer metastasis by promoting the secretion of CD81+ exosomes through the Rab27a/SYTL1/CD81 transport complexes. Consequently, our observations provide new insights into the potential clinical application of CD81+ exosome-based cancer therapy. Metastasis, a major cause of cancer-related mortality worldwide, frequently occurs early in the diagnosis of lung adenocarcinoma (LUAD). However, the precise molecular mechanisms governing the aggressive metastatic behavior of LUAD remain incompletely understood. In this study, we present compelling evidence indicating that the long noncoding RNA linc01703 is significantly downregulated in metastatic lung cancer cells. Intriguingly, in vivo experiments revealed that Linc01703 exerted a profound inhibitory effect on lung cancer metastasis without discernible impact on the in vitro proliferation or invasion capacities of LUAD cells. Mechanistically, Linc01703 enhanced the interaction between Rab27a, SYTL1, and CD81, consequently promoting the secretion of CD81+ exosomes. These exosomes, in turn, suppressed the infiltration of immune cells within the tumor microenvironment, thereby impeding LUAD metastasis. Importantly, our analysis of lung cancer tissues revealed a correlation between reduced CD81 expression and an unfavorable patient prognosis. Collectively, our findings suggest that Linc01703 functions as a metastasis suppressor by facilitating the secretion of CD81+ exosomes through the formation of the Rab27a/SYTL1/CD81 complex. [ABSTRACT FROM AUTHOR]

Paradoxically, during early tumor development in many cancer types, TGF-[beta] acts as a tumor suppressor, whereas in the advanced stages of these cancers, increased TGF-[beta] expression is linked to high metastasis and poor prognosis. These findings suggest that unidentified mechanisms may function to rewire TGF-[beta] signaling toward its prometastatic role in cancer cells. Our current study using non--small-cell lung carcinoma (NSCLC) cell lines, animal models, and clinical specimens demonstrates that suppression of SMAD2, with SMAD3 function intact, switches TGF-[beta]--induced transcriptional responses to a prometastatic state. Importantly, we identified chaperonin containing TCP1 subunit 6A (CCT6A) as an inhibitor and direct binding protein of SMAD2 and found that CCT6A suppresses SMAD2 function in NSCLC cells and promotes metastasis. Furthermore, selective inhibition of SMAD3 or CCT6A efficiently suppresses TGF-[beta]--mediated metastasis. Our findings provide a mechanism that directs TGF-[beta] signaling toward its prometastatic arm and may contribute to the development of therapeutic strategies targeting TGF-[beta] for NSCLC., Introduction Non--small-cell lung carcinoma (NSCLC) is among the most commonly diagnosed cancers worldwide (1, 2). The prognosis of NSCLC remains poor, and the overall 5-year relative survival rate, including all [...]

The importance of mRNA N6‐methyladenosine (m6A) modification during tumor metastasis is controversial as it plays distinct roles in different biological contexts. Moreover, how cancer cell plasticity is shaped by m6A modification is interesting but remains uncharacterized. Here, this work shows that m6A reader insulin like growth factor 2 mRNA binding protein 3 (IGF2BP3) is remarkably upregulated in metastatic lung adenocarcinoma (LUAD) and indicates worse prognosis of patients. Interestingly, IGF2BP3 induces partial epithelial‐mesenchymal‐transition (EMT) and confers LUAD cells plasticity to metastasize through m6A‐dependent overactivation of Notch signaling. Mechanistically, IGF2BP3 recognized m6A‐modified minichromosome maintenance complex component (MCM5) mRNAs to prolong stability of them, subsequently upregulating MCM5 protein, which competitively inhibits SIRT1‐mediated deacetylation of Notch1 intracellular domain (NICD1), stabilizes NICD1 protein and contributes to m6A‐dependent IGF2BP3‐mediated cellular plasticity. Notably, a tight correlation of the IGF2BP3/MCM5/Notch axis is evidenced in clinical LUAD specimens. Therefore, this study elucidates a critical role of m6A modification on LUAD cell plasticity in fostering tumor metastasis via the above axis, providing potential targets for metastatic LUAD. [ABSTRACT FROM AUTHOR]

JAK2 activity is tightly controlled through a self-inhibitory effect via its JAK homology domain 2 (JH2), which restricts the strength and duration of JAK2/STAT3 signaling under physiological conditions. Although multiple [...]

Tumor metastasis involves a series of biological steps during which the tumor cells acquire the ability to invade surrounding tissues and survive outside the original tumor site. During the early stages, the cancer cells undergo an epithelial-mesenchymal transition (EMT). Wnt/β-catenin signaling is known to drive EMT and metastasis. Here we report that Wnt/β-catenin signaling is hyperactivated in metastatic breast cancer cells that express microRNA 374a (miR-374a). In breast cancer cell lines, ectopic overexpression of miR-374a promoted EMT and metastasis both in vitro and in vivo. Furthermore, miR-374a directly targeted and suppressed multiple negative regulators of the Wnt/β-catenin signaling cascade, including WIF1, PTEN, and WNT5A. Notably, miR-374a was markedly upregulated in primary tumor samples from patients with distant metastases and was associated with poor metastasis-free survival. These results demonstrate that miR-374a maintains constitutively activated Wnt/β-catenin signaling and may represent a therapeutic target for early metastatic breast cancer., Introduction Distant metastasis and invasion of cancer are responsible for more than 90% of cancer-related deaths (1). Biologically, the process of tumor metastasis consists of multiple sequential steps, including invasion [...]

The strength and. d_uration of NF-κB signaling are tightly controlled. by multiple negative feed.back mechanisms. However, in cancer cells, these feed.back loops are overridden through unclear mechanisms to sustain oncogenic activation of NF-κB signaling. Previously, we demonstrated that overexpression of miR-30e* directly represses IKBα expression and lead.s to hyperactivation of NF-κB. Here, we report that miR-182 was overexpressed. in a different set of gliomas with relatively lower miR-30e* expression and. that miR-182 directly suppressed cylindromatosis (CYLD), an NF-κB negative regulator. This suppression of CYLD promoted ubiquitin conjugation of NF-κB signaling pathway components and. induction of an aggressive phenotype of glioma cells both in vitro and. in vivo. Furthermore, we found. that TGF-β induced. miR-182 expression, leading to prolonged. NF-κB activation. Importantly, the results of these experiments were consistent with an identified significant correlation between miR-182 levels with TGF-β hyperactivation and activated. NF-κB in a cohort of human glioma specimens. These findings uncover a plausible mechanism for sustained. NF-κB activation in malignant gliomas and. may suggest a new target for clinical intervention in human cancer., Introduction The NF-κB pathway, serving as a mechanistic link between inflammation and cancer development, is constitutively activated in various types of cancers (1-4). Over the last decade, ubiquitin (Ub) modification [...]

Constitutive activation of NF-κ B is a frequent event in human cancers, playing important roles in cancer development and progression. In nontransformed cells, NF-κ B activation is tightly controlled by I κ Bs. I κ Bs bind NF-κ B in the cytoplasm, preventing it from translocating to the nucleus to modulate gene expression. Stimuli that activate NF-κ B signaling trigger Iκ B degradation, enabling nuclear translocation of NF-κ B. Among the genes regulated by NF-κ B are those encoding the I κ Bs, providing a negative feedback loop that limits NF-κ B activity. How transformed cells override this NF-κ B/I κ B negative feedback loop remains unclear. Here, we report in human glioma cell lines that microRNA-30e* (miR-30e*) directly targets the IκBα 3 -UTR and suppresses IκBα expression. Overexpression of miR-30e* in human glioma cell lines led to hyperactivation of NF-κ B and enhanced expression of NF-κ B-regulated genes, which promoted glioma cell invasiveness in in vitro assays and in an orthotopic xenotransplantation model. These effects of miR-30e* were shown to be clinically relevant, as miR-30e* was found to be upregulated in primary human glioma cells and correlated with malignant progression and poor survival. Hence, miR-30e* provides an epigenetic mechanism that disrupts the NF-κ B/IκBα loop and may represent a new therapeutic target and prognostic marker., Introduction Since its discovery in 1986 (1), NF-κ B has been recognized as one of the most pleiotropic transcription factors and a key player in the regulation of inflammatory and [...]

Simple Summary: We show that CLU, especially cytoplasmic precursor CLU, is downregulated in lung cancer and correlates with poor survival. The silencing of CLU promotes lung cancer cell migration and invasion, while the overexpression of CLU potently inhibits these phenomena. Interestingly, secretory CLU proteins are slightly decreased in lung cancer tissue and fail to exert similar anti-metastatic effects like cytoplasmic precursor CLU, demonstrating that cytoplasmic precursor CLU is the primary functional isoform of CLU, which exerts the anti-metastatic effects of lung cancer. Mechanistically, cytoplasmic precursor CLU binds ROCK1 to decrease phosphorylation of ERK1/2 by inhibiting the kinase activity of ROCK1, leading to an anti-metastatic effect in lung cancer cells. These findings reveal a novel insight into the function and regulation of cytoplasmic CLU in lung cancer, which might be a potential target for the diagnosis and treatment of metastatic lung cancer. Clusterin (CLU) is a heterodimeric glycoprotein that has been detected in diverse human tissues and implicated in many cellular processes. Accumulating evidence indicates that the expression of secreted CLU correlates with the progression of cancers. However, the molecular mechanisms underlying its tumor-suppressive roles are incompletely uncovered. In this study, we demonstrate that precursor CLU is widely downregulated in lung cancer tissue, in which secretory CLU proteins are slightly decreased. Impressively, overexpressing CLU potently inhibits the migration, invasion and metastasis of lung cancer cells, whereas silencing CLU promotes this behavior; however, it appears that secretory CLU fails to exert similar anti-metastatic effects. Interestingly, the cytoplasmic precursor CLU binds ROCK1 to abrogate the interaction between ROCK1 and ERK and impair ERK activity, leading to the suppression of lung cancer invasiveness. Meanwhile, the expression of CLU was remarkably diminished in lung cancer bone metastasis loci when compared with subcutaneous tumors in the mouse model and hardly detected in the bone metastasis loci of lung cancer patients when compared with the primary. These findings reveal a novel insight into the function and regulation of cytoplasmic CLU in lung cancer, which might be a potential target for the diagnosis and treatment of metastatic lung cancer. [ABSTRACT FROM AUTHOR]

Abstract Background The prognosis of human glioma is poor, and the highly invasive nature of the disease represents a major impediment to current therapeutic modalities. The oncoprotein B-cell-specific Moloney murine leukemia virus integration site 1 protein (Bmi-1) has been linked to the development and progression of glioma; however, the biological role of Bmi-1 in the invasion of glioma remains unclear. Methods A172 and LN229 glioma cells were engineered to overexpress Bmi-1 via stable transfection or to be silenced for Bmi-1 expression using RNA interfering method. Migration and invasiveness of the engineered cells were assessed using wound healing assay, Transwell migration assay, Transwell matrix penetration assay and 3-D spheroid invasion assay. MMP-9 expression and activity were measured using real-time PCR, ELISA and the gelatin zymography methods. Expression of NF-kappaB target genes was quantified using real-time PCR. NF-kappaB transcriptional activity was assessed using an NF-kappaB luciferase reporter system. Expression of Bmi-1 and MMP-9 in clinical specimens was analyzed using immunohistochemical assay. Results Ectopic overexpression of Bmi-1 dramatically increased, whereas knockdown of endogenous Bmi-1 reduced, the invasiveness and migration of glioma cells. NF-kappaB transcriptional activity and MMP-9 expression and activity were significantly increased in Bmi-1-overexpressing but reduced in Bmi-1-silenced cells. The reporter luciferase activity driven by MMP-9 promoter in Bmi-1-overexpressing cells was dependent on the presence of a functional NF-kappaB binding site, and blockade of NF-kappaB signaling inhibited the upregulation of MMP-9 in Bmi-1 overexpressing cells. Furthermore, expression of Bmi-1 correlated with NF-kappaB nuclear translocation as well as MMP-9 expression in clinical glioma samples. Conclusions Bmi-1 may play an important role in the development of aggressive phenotype of glioma via activating the NF-kappaB/MMP-9 pathway and therefore might represent a novel therapeutic target for glioma.

The incidence of bone metastases in hepatocellular carcinoma (HCC) has increased prominently over the past decade owing to the prolonged overall survival of HCC patients. However, the mechanisms underlying HCC bone‐metastasis remain largely unknown. In the current study, HCC‐secreted lectin galactoside‐binding soluble 3 (LGALS3) is found to be significantly upregulated and correlates with shorter bone‐metastasis‐free survival of HCC patients. Overexpression of LGALS3 enhances the metastatic capability of HCC cells to bone and induces skeletal‐related events by forming a bone pre‐metastatic niche via promoting osteoclast fusion and podosome formation. Mechanically, ubiquitin ligaseRNF219‐meidated α‐catenin degradation prompts YAP1/β‐catenin complex‐dependent epigenetic modifications of LGALS3 promoter, resulting in LGALS3 upregulation and metastatic bone diseases. Importantly, treatment with verteporfin, a clinical drug for macular degeneration, decreases LGALS3 expression and effectively inhibits skeletal complications of HCC. These findings unveil a plausible role for HCC‐secreted LGALS3 in pre‐metastatic niche and can suggest a promising strategy for clinical intervention in HCC bone‐metastasis. [ABSTRACT FROM AUTHOR]

Tumour‐associated macrophages (TAMs), which possess M2‐like characters and are derived from immature monocytes in the circulatory system, represent a predominant population of inflammatory cells in solid tumours. TAM infiltration in tumour microenvironment can be used as an important prognostic marker in many cancer types and is a potential target for cancer prevention or treatment. VEGI‐251 not only is involved in the inhibition of tumour angiogenesis, but also participates in the regulation of host immunity. This work aimed to investigate the involvement of VEGI‐251 in the regulation of specific antitumour immunity. We found that recombinant human VEGI‐251(rhVEGI‐251) efficiently mediated the elimination of TAMs in tumour tissue in mice, and induced apoptosis of purified TAMs in vitro. During this process, caspase‐8 and caspase‐3 were activated, leading to PARP cleavage and apoptosis. Most importantly, we further elucidated the mechanism underlying VEGI‐251‐triggered TAM apoptosis, which suggests that ASK1, an intermediate component of the VEGI‐251, activates the JNK pathway via TRAF2 in a potentially DR3‐dependent manner in the process of TAM apoptosis. Collectively, our findings provide new insights into the basic mechanisms underlying the actions of VEGI‐251 that might lead to future development of antitumour therapeutic strategies using VEGI‐251 to target TAMs. [ABSTRACT FROM AUTHOR]

Long noncoding RNAs (lncRNAs) are involved in the pathology of various tumours, including non‐small cell lung cancer (NSCLC). However, the underlying molecular mechanisms of their specific association with NSCLC have not been fully elucidated. Here, we report that a cytoplasmic lncRNA, DUXAP9‐206 is overexpressed in NSCLC cells and closely related to NSCLC clinical features and poor patient survival. We reveal that DUXAP9‐206 induced NSCLC cell proliferation and metastasis by directly interacting with Cbl‐b, an E3 ubiquitin ligase, and reducing the degradation of epidermal growth factor receptor (EGFR) and thereby augmenting EGFR signaling in NSCLC. Notably, correlations between DUXAP9‐206 and activated EGFR signaling were also validated in NSCLC patient specimens. Collectively, our findings reveal the novel molecular mechanisms of DUXAP9‐206 in mediating the progression of NSCLC and DUXAP9‐206 may serve as a potential target for NSCLC therapy. [ABSTRACT FROM AUTHOR]

Summary Objective It has been well recognized that microRNA plays a role in the host–pathogen interaction network. The significance of microRNA in the regulation of dengue virus (DENV) replication, however, remains unknown. The objective of our study was to determine the biological function of miR-548g-3p in modulating the replication of dengue virus. Methods Here we report that employment of a microRNA target search algorithm to analyze the 5′ untranslated region (5′UTR) consensus sequences of DENV (DENV serotypes 1–4) led to a discovery that miR-548g-3p directly targets the stem loop A promoter element within the 5′UTR, a region essential for DENV replication. Real-time PCR was used to measure the expression levels of miR-548g-3p under DENV infection. We performed overexpression and inhibition assays to test the role of miR-548g-3p on DENV replication. The protein and mRNA levels of interferon were measured by ELISA and real-time PCR respectively. Result We found that overexpression of miR-548g-3p suppressed multiplication of DENV 1, 2, 3 and 4, and that miR-548g-3p was also found to interfere with DENV translation, thereby suppressing the expression of viral proteins. Conclusion Our results suggest that miR-548g-3p directly regulates DENV replication and warrant further study to investigate the feasibility of microRNA-based anti-DENV approaches. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma ( HCC) is one of the most lethal malignancies, in which the NF-κ B pathway plays an important role and is constitutively activated. Better understanding of the molecular pathogenesis of HCC and the NF-κ B pathway are needed to improve patient outcomes. Herein, we identified an unappreciated protein involved in NF-κ B-induced activation, Golgi phosphoprotein 3 ( GOLPH3). The mRNA and protein expression levels of GOLPH3 were frequently up-regulated in HCC and GOLPH3 expression correlated closely with clinical stage and survival in both the testing and validation cohorts. Ectopic over-expression of GOLPH3 in PLC/ PRF/5 ( PLC) and Huh7 HCC cells protected against cisplatin-induced apoptosis, promoted angiogenesis and proliferation and increased the aggressiveness of HCC cells in vitro and in vivo, whereas inhibition of GOLPH3 led to decreased aggressiveness. Through analysis of two published HCC patient profiles, GOLPH3 expression significantly correlated with NF-κ B signalling. Furthermore, we demonstrated that GOLPH3 promoted K63-linked polyubiquitination of tumour necrosis factor receptor-associated factor 2 ( TRAF2), receptor interacting protein ( RIP) and NF-κ B essential modulator ( NEMO) and substantially sustained the activation of NF-κ B in HCC cells. Taken together, our findings provided evidence that GOLPH3 is a prognostic and/or potential therapeutic biomarker for HCC patients and plays an important role in activation of the NF-κ B pathway during HCC progression. Copyright © 2014 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Interferon-inducible transmembrane proteins 1, 2 and 3 ( IFITM1, IFITM2 and IFITM3) have recently been identified as potent antiviral effectors that function to suppress the entry of a broad range of enveloped viruses and modulate cellular tropism independent of viral receptor expression. However, the antiviral effect and mechanisms of IFITMs in response to viral infections remain incompletely understood and characterized. In this work, we focused our investigation on the function of the extracellular IFITM3 protein. In cell models of DENV-2 infection, we found that IFITM3 contributed to both the baseline and interferon-induced inhibition of DENV entry. Most importantly, our study for the first time demonstrated the presence of IFITM-containing exosome in the extracellular environment, and identified an ability of cellular exosome to intercellularly deliver IFITM3 and thus transmit its antiviral effect from infected to non-infected cells. Thus, our findings provide new insights in the basic mechanisms underlying the actions of IFITM3, which might lead to future development of exosome-mediated anti-viral strategies using IFITM3 as a therapeutic agent. Conceivably, variations in the basal and inducible levels of IFITMs, as well as in intracellular and extracellular levels of IFITMs, might predict the severity of dengue virus infections among individuals or across species. [ABSTRACT FROM AUTHOR]