Publications by authors named "Lo-Kong Chan"

Article Synopsis
  • Metabolic reprogramming in cancer is closely linked to hypoxia, which aids rapid tumor growth and reduces oxidative stress; PFKFB, a key glycolytic enzyme, is vital in various cancers but its role in hepatocellular carcinoma (HCC) is not well-studied.
  • The researchers analyzed PFKFB4 expression using RNA sequencing and confirmed its up-regulation in HCC through various methods, discovering a correlation with certain genetic mutations and aggressive tumor behavior.
  • Functional studies using CRISPR/Cas9 to knock out PFKFB4 demonstrated that its loss impaired HCC development and altered metabolite levels, affecting pathways like glycolysis and the pentose phosphate pathway.
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Background And Aims: Understanding the mechanisms of HCC progression and metastasis is crucial to improve early diagnosis and treatment. This study aimed to identify key molecular targets involved in HCC metastasis.

Approach And Results: Using whole-transcriptome sequencing of patients' HCCs, we identified and validated midline 1 interacting protein 1 (MID1IP1) as one of the most significantly upregulated genes in metastatic HCCs, suggesting its potential role in HCC metastasis.

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Background: Lines of evidence implicate CENPF and FOXM1 may have novel co-operative roles in driving hepatocellular carcinoma (HCC).

Objective: We investigated the clinicopathological correlation, functional characterization, molecular mechanism and translational significance of CENPF and FOXM1.

Methods: We carried out integrative studies investigating functional synergism of CENPF and FOXM1 in HCC and its metastasis.

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Background & Aims: The highly proliferative nature of hepatocellular carcinoma (HCC) frequently results in a hypoxic intratumoural microenvironment, which creates a therapeutic challenge owing to a lack of mechanistic understanding of the phenomenon. We aimed to identify critical drivers of HCC development and progression in the hypoxic microenvironment.

Methods: We performed integrative analysis of multiple transcriptomic and genomic profiles specific for HCC and hypoxia and identified the Ephrin-A3/Eph receptor A2 (EphA2) axis as a clinically relevant and hypoxia-inducible signalling axis in HCC.

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Background: Controversy over the benefits of antioxidants supplements in cancers persists for long. Using hepatocellular carcinoma (HCC) as a model, we investigated the effects of exogenous antioxidants N-acetylcysteine (NAC) and glutathione (GSH) on tumor formation and growth.

Methods: Multiple mouse models, including diethylnitrosamine (DEN)-induced and Trp53KO/C-MycOE-induced HCC models, mouse hepatoma cell and human HCC cell xenograft models with subcutaneous or orthotopic injection were used.

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Background And Aims: Ras-like (Ral) small guanosine triphosphatases (GTPases), RalA and RalB, are proto-oncogenes directly downstream of Ras and cycle between the active guanosine triphosphate-bound and inactive guanosine diphosphate-bound forms. RalGTPase-activating protein (RalGAP) complex exerts a negative regulation. Currently, the role of Ral up-regulation in cancers remains unclear.

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Interaction between tumor cells and immune cells in the tumor microenvironment is important in cancer development. Immune cells interact with the tumor cells to shape this process. Here, we use single-cell RNA sequencing analysis to delineate the immune landscape and tumor heterogeneity in a cohort of patients with HBV-associated human hepatocellular carcinoma (HCC).

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Hepatocarcinogenesis involves complex genetic and cellular dysregulations which drive the formation of hepatocellular carcinoma (HCC), the predominant form of primary liver cancer, with extensive heterogeneity. In contrast to the broad spectrum of molecularly driven therapies available for defined patient groups in certain cancer types, unfortunately the treatment options for HCC are highly limited. The lack of representative molecular and cellular signatures in the heterogeneous HCC tumors that can effectively guide the choice of the most appropriate treatment among the patients unavoidably limits the treatment outcome.

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Background & Aims: Mutational profiling of patient tumors has suggested that hepatocellular carcinoma (HCC) development is mainly driven by loss-of-function mutations in tumor suppressor genes. p90 ribosomal S6 kinase 2 (RSK2) functions as a direct downstream kinase of ERK1/2 and elevated RSK2 expression has been reported to support oncogenic functions in some cancers. We investigated if RSK2 was also dysregulated by inactivating mutations in cancers including HCC.

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Cancer stemness, referring to the stem-cell-like phenotype of cancer cells, has been recognised to play important roles in different aspects of hepatocarcinogenesis. A number of well-established cell-surface markers already exist for liver cancer stem cells, with potential new markers of liver cancer stem cells being identified. Both genetic and epigenetic factors that affect various signalling pathways are known to contribute to cancer stemness.

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Article Synopsis
  • Hepatitis B virus (HBV) integrations are common in hepatocellular carcinoma (HCC) and often affect the telomerase reverse transcriptase (TERT) gene, leading to increased TERT expression and more aggressive tumors.
  • A study analyzed HBV integrations in 95 human HCC cases and found that 35.8% had HBV integration at the TERT promoter, which was linked to TERT activation.
  • The research identified the E74 like ETS transcription factor 4 (ELF4) as a key player in this process, as it interacts with HBV components to promote TERT transcription, suggesting a mechanism for how HBV-related HCC develops.
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Hepatocellular carcinoma (HCC) is heterogeneous, rendering its current curative treatments ineffective. The emergence of single-cell genomics represents a powerful strategy in delineating the complex molecular landscapes of cancers. In this study, we demonstrated the feasibility and merit of using single-cell RNA sequencing to dissect the intra-tumoral heterogeneity and analyze the single-cell transcriptomic landscape to detect rare cell subpopulations of significance.

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Article Synopsis
  • Cytidine deaminase APOBEC3B (A3B) is linked to C-to-T mutations in cancers and was studied for its role in hepatocellular carcinoma (HCC), showing overexpression in human HCC cases.
  • Higher levels of A3B were associated with more aggressive tumor behavior and increased tumor growth and spread in HCC cells.
  • Interestingly, even a mutant form of A3B without deaminase activity displayed similar effects as the normal version, revealing a new way A3B contributes to cancer progression, independent of its known enzymatic function.
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Following epithelial-mesenchymal transition, acquisition of avian trunk neural crest cell (NCC) polarity is prerequisite for directional delamination and migration, which in turn is essential for peripheral nervous system development. However, how this cell polarization is established and regulated remains unknown. Here we demonstrate that, using the RHOA biosensor in vivo and in vitro, the initiation of NCC polarization is accompanied by highly activated RHOA in the cytoplasm at the cell rear and its fluctuating activity at the front edge.

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Objective: We investigated the effect and mechanism of hypoxic microenvironment and hypoxia-inducible factors (HIFs) on hepatocellular carcinoma (HCC) cancer stemness.

Design: HCC cancer stemness was analysed by self-renewal ability, chemoresistance, expression of stemness-related genes and cancer stem cell (CSC) marker-positive cell population. Specific small ubiquitin-like modifier (SUMO) proteases 1 (SENP1) mRNA level was examined with quantitative PCR in human paired HCCs.

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The pathogenesis of hepatocellular carcinoma (HCC) is a multistep process involving the progressive accumulation of molecular alterations pinpointing different molecular and cellular events. The next-generation sequencing technology is facilitating the global and systematic evaluation of molecular landscapes in HCC. There is emerging evidence supporting the importance of cancer metabolism and tumor microenvironment in providing a favorable and supportive niche to expedite HCC development.

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Small Rho GTPase (Rho) and its immediate effector Rho kinase (ROCK) are reported to regulate cell survival, but the detailed molecular mechanism remains largely unknown. We had previously shown that Rho/ROCK signaling was highly activated in hepatocellular carcinoma (HCC). In this study, we further demonstrated that downregulation of RhoE, a RhoA antagonist, and upregulation of ROCK enhanced resistance to chemotherapy in HCC in both in vitro cell and in vivo murine xenograft models, whereas a ROCK inhibitor was able to profoundly sensitize HCC tumors to cisplatin treatment.

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Unlabelled: Cancer metastasis is a multistep process that involves a series of tumor-stromal interaction, including extracellular matrix (ECM) remodeling, which requires a concerted action of multiple proteolytic enzymes and their endogenous inhibitors. This study investigated the role of tissue inhibitor of metalloproteinases (TIMP) 2 in the context of hepatocellular carcinoma (HCC) metastasis. We found that TIMP2 was the most significantly down-regulated member among the TIMP family in human HCCs.

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Background & Aims: Hepatitis B virus (HBV) integration is common in HBV-associated hepatocellular carcinoma (HCC) and may play an important pathogenic role through the production of chimeric HBV-human transcripts. We aimed to screen the transcriptome for HBV integrations in HCCs.

Methods: Transcriptome sequencing was performed on paired HBV-associated HCCs and corresponding non-tumorous liver tissues to identify viral-human chimeric sites.

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The focal adhesion protein Tensin4, also known as cten (c-terminal tensin like), is structurally distinct from the three other members in the Tensin family. Its expression and potential functions in cancers including hepatocellular carcinoma (HCC) are not well understood. With immunohistochemistry, 43% (13/30) of our human HCC cases showed up-regulation of Tensin4 as compared with their corresponding non-tumorous livers.

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Deleted in Liver Cancer 1 (DLC1) is a tumour suppressor that encodes a RhoGTPase-activating protein (RhoGAP) and is frequently inactivated in many human cancers. The RhoGAP activity of DLC1 against Rho signalling is well documented and is strongly associated with the tumour suppressor functions of DLC1. However, the mechanism by which the RhoGAP activity of DLC1 is regulated remains obscure.

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Caveolin-1 (Cav1) has been implicated in diverse human cancers, yet its role in hepatocellular carcinoma (HCC) tumourigenesis and metastasis remains elusive. In the current study, we aim to provide a comprehensive understanding regarding the functional role of Cav1 in HCC tumourigenesis and metastasis. Cav1 expression was examined in a panel of human HCC cell lines using western blotting analysis and quantitative RT-PCR and human tissues by immunohistochemistry.

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Background: Deleted in liver cancer 1 (DLC1) serves as an important RhoGTPase activating protein (RhoGAP) protein that terminates active RhoA signaling in human cancers. Increasing evidence has demonstrated that the tumor suppressive activity of DLC1 depends not only on RhoGAP activity, but also relies on proper focal adhesion localization through its interaction with tensin family proteins. Recently, there are reports showing that DLC1 can also be found in the nucleus; however, the existence and the relative tumor suppressive activity of nuclear DLC1 have never been clearly addressed.

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