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Macropinocytosis is an effective strategy to mitigate nutrient starvation. It can fuel cancer cell growth in nutrient‐limited conditions. However, whether and how macropinocytosis contributes to the rapid proliferation of hepatocellular carcinoma cells, which frequently experience an inadequate nutrient supply, remains unclear. Here, we demonstrated that nutrient starvation strongly induced macropinocytosis in some hepatocellular carcinoma cells. It allowed the cells to acquire extracellular nutrients and supported their energy supply to maintain rapid proliferation. Furthermore, we found that the phospholipid flippase ATP9A was critical for regulating macropinocytosis in hepatocellular carcinoma cells and that high ATP9A levels predicted a poor outcome for patients with hepatocellular carcinoma. ATP9A interacted with ATP6V1A and facilitated its transport to the plasma membrane, which promoted plasma membrane cholesterol accumulation and drove RAC1‐dependent macropinocytosis. Macropinocytosis inhibitors significantly suppressed the energy supply and proliferation of hepatocellular carcinoma cells characterised by high ATP9A expression under nutrient‐limited conditions. These results have revealed a novel mechanism that overcomes nutrient starvation in hepatocellular carcinoma cells and have identified the key regulator of macropinocytosis in hepatocellular carcinoma. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland. [ABSTRACT FROM AUTHOR]

Non‐small‐cell lung cancer (NSCLC), in which the NF‐κB pathway is constitutively activated, is one of the most common malignancies. Herein, we identify an E3 ubiquitin ligase, tripartite motif‐containing 37 (TRIM37), participating in the K63 polyubiquitination of TRAF2, which is a significant step in the activation of NF‐κB signaling. Both the mRNA and the protein expression levels of TRIM37 were much higher in NSCLC cell lines and tissues than in normal bronchial epithelial cells and matched adjacent non‐tumor tissues. TRIM37 expression correlated closely with clinical stage and poor survival in NSCLC. Overexpression of TRIM37 antagonized cisplatin‐induced apoptosis, induced angiogenesis and proliferation, and increased the aggressiveness of NSCLC cells in vitro and in vivo, whereas inhibition of TRIM37 led to the opposite effects. Gene set enrichment analysis (GSEA) showed that TRIM37 expression significantly correlated with NF‐κB signaling. Furthermore, we found that TRIM37 bound to TRAF2 and promoted K63‐linked ubiquitination of TRAF2, sustaining the eventual activation of the NF‐κB pathway. Mutation in the ring finger domain of TRIM37, a hallmark of E3 ubiquitin ligases, led to loss of the ability to promote K63 polyubiquitination of TRAF2 and activate NF‐κB signaling. Taken together, our findings provide evidence that TRIM37 plays an important role in constitutive NF‐κB pathway activation and could serve as a prognostic factor and therapeutic target in NSCLC. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Cancer stem cells (CSCs) are commonly associated with cancer recurrence and metastasis that occurs in up to 30-55% of non-small-cell lung carcinoma (NSCLC) patients. Herein, we showed that serine-arginine protein kinase 1 (SRPK1) was highly expressed at both the mRNA and the protein levels in human NCSLC. SRPK1 was associated with the clinical features of human NSCLC, including clinical stage (p < 0.001) and T (p = 0.001), N (p = 0.007), and M (p = 0.001) classifications. Ectopic overexpression of SRPK1 promoted the acquisition of a stem cell-like phenotype in human NSCLC cell lines cultured in vitro. Overexpression of SRPK1 increased sphere formation and the proportion of side-population cells that exclude Hoechst dye. Conversely, SRPK1 silencing reduced the number of spheres and the proportion of side-population cells. Mouse studies indicated that SRPK1 promoted NSCLC cell line tumour growth and SRPK1 overexpression reduced the number of tumour cells required to initiate tumourigenesis in vivo. Mechanistically, gene set enrichment analysis showed that Wnt/β-catenin signalling correlated with SRPK1 mRNA levels and this signalling pathway was hyperactivated by ectopic SRPK1 expression in NSCLC cell lines. Immunofluorescence demonstrated that SRPK1 enhanced β-catenin accumulation in the nuclei of NSCLC cell lines, and inhibition of β-catenin signalling abrogated the SRPK1-induced stem cell-like phenotype. Together, our findings suggest that SRPK1 promotes a stem cell-like phenotype in NSCLC via Wnt/β-catenin signalling. Moreover, SRPK1 may represent a novel target for human NSCLC diagnosis and therapy. [ABSTRACT FROM AUTHOR]

Breast cancer is the most common malignancy in females. The presence of cancer stem cells ( CSCs) is the main cause of local and distant tumour recurrence and is associated with poor outcome in breast cancer. However, the molecular mechanisms underlying the maintenance of CSCs remain largely unknown. This study demonstrates that prostate tumour overexpressed-1 ( PTOV1) enhances the CSC population and augments the tumourigenicity of breast cancer cells both in vitro and in vivo. Moreover, PTOV1 suppresses transcription of Dickkopf-1 ( DKK1) by recruiting histone deacetylases and subsequently reducing DKK1 promoter histone acetylation, followed by activation of Wnt/β-catenin signalling. Restoration of DKK1 expression in PTOV1-overexpressing cells counteracts the effects of PTOV1 on Wnt/β-catenin activation and the CSC population. Collectively, these results suggest that PTOV1 positively regulates the Wnt/β-catenin signalling pathway and enhances tumourigenicity in breast cancer; this novel mechanism may represent a therapeutic target for breast cancer. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [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]

Stomatin-like protein 2 (STOML2), a member of the stomatin family, has been reported to be up-regulated in several types of human cancers. The clinical significance and biological role of STOML2 in gliomas remain largely unknown. Here, we describe the significantly up-regulated expression of STOML2 in glioma cell lines and glioma tissues at both the transcriptional and translational levels. Silencing endogenous STOML2 in glioma cells and primary glioma cells drastically reduced their migratory speed and invasive ability, associated with induction of matrix metallopeptidase 9 (MMP-9). We also demonstrated that knockdown of STOML2 significantly inhibited the transcriptional activity of NF-κB and repressed the expression levels of NF-κB target genes, including MMP-9. A luciferase reporter assay revealed that the impact of STOML2 on MMP-9 expression is NF-κB-dependent. Immunohistochemical analysis showed that the up-regulation of STOML2 was significantly correlated with the WHO histological grade of gliomas ( p < 0.001). Patients with higher STOML2 expression levels had an overall shorter survival time, whereas patients with lower expression of STOML2 had a longer survival time. A multivariate analysis revealed that STOML2 expression might be an independent prognostic indicator for the survival of glioma patients. Taken together, our results suggest that overexpression of STOML2 is associated with glioma aggressiveness and may represent an independent prognostic factor for the outcome of glioma patients. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The biosynthesis and metabolism of RNA play important roles in regulating gene expression. On the other hand, it has been shown that RNA expression profiling is differentially distinct between cancer and normal cells, suggesting the possibility that aberrant regulation of RNA metabolism might be associated with the development and progression of cancer. In the current study, we found that Sam68, an RNA-binding protein that links cellular signalling to RNA processing, was markedly overexpressed in breast cancer cells and tissues. Immunohistochemical analysis showed that the expression and cytoplasmic localization of Sam68 significantly correlated with clinical characteristics of patients, including clinical stage, tumour-nodule-metastasis (TNM) classification, histological grade, and ER expression. Univariate and multivariate analyses showed that the expression level and cytoplasmic localization of Sam68 were identified as independent prognostic factors. Furthermore, we found that siRNA knockdown of endogenous Sam68 inhibited cell proliferation and tumourigenicity of breast cancer cells in vitro, through blocking the G1 to S phase transition. Moreover, we demonstrated that the anti-proliferative effect of silencing Sam68 on breast cancer cells was associated with up-regulation of cyclin-dependent kinase inhibitor p21Cip1 and p27Kip1, enhanced transactivation of FOXO factors, and attenuation of Akt/GSK-3β signalling. Taken together, our results suggest that Sam68 might play an important role in promoting the proliferation and carcinogenesis of human breast cancer, and thereby might be a novel and useful prognostic marker and a potential target for human breast cancer treatment. Copyright © 2010 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Astrocyte elevated gene 1 (AEG-1), a novel oncoprotein, has been implicated in oncogenesis and cancer progression in various types of human cancers. The clinical significance and biological role of AEG-1 in non-small cell lung cancer (NSCLC), however, remain unclear. In the present study, we found that the expression of AEG-1 was markedly up-regulated in NSCLC cell lines and NSCLC tissues at the level of both transcription and translation. Ectopically expressed AEG-1 enhanced the migratory and invasive abilities of NSCLC cells, whereas knockdown of endogenous AEG-1 by specific shRNAs significantly inhibited these abilities. The function of AEG-1 on metastasis modulation was associated with the activation of the PI3K-Akt and NF-κB signalling pathways. Furthermore, we showed high expression of AEG-1 in 99/200 (49.5%) paraffin-embedded archival NSCLC specimens. Moreover, statistical analysis displayed a significant correlation in AEG-1 expression with the clinical stage ( p < 0.001), T classification ( p = 0.001), N classification ( p = 0.015), distant metastasis ( p = 0.004) and differentiation ( p = 0.027). Patients with higher AEG-1 expression had an overall shorter survival time, whereas patients with lower expression of AEG-1 had a better survival time. Multivariate analysis suggested that AEG-1 expression might be an independent prognostic indicator for the survival of NSCLC patients. Taken together, our results suggest that elevated expression of AEG-1 plays an important role in the aggressiveness of NSCLC, leading to a poor clinical outcome. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) is one of the most lethal malignancies, in which the NF-κB pathway plays an important role and is constitutively activated. Better understanding of the molecular pathogenesis of HCC and the NF-κB pathway are needed to improve patient outcomes. Herein, we identified an unappreciated protein involved in NF-κB-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-κB 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-κB essential modulator (NEMO) and substantially sustained the activation of NF-κB 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-κB pathway during HCC progression., (Copyright © 2014 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.)