Mitochondrial dynamics plays an important role in tumour progression. However, how these dynamics integrate tumour metabolism in hepatocellular carcinoma (HCC) metastasis is still unclear.
The ...mitochondrial fusion protein mitofusin-1 (MFN1) expression and its prognostic value are detected in HCC. The effects and underlying mechanisms of MFN1 on HCC metastasis and metabolic reprogramming are analysed both in vitro and in vivo.
Mitochondrial dynamics, represented by constant fission and fusion, are found to be associated with HCC metastasis. High metastatic HCC displays excessive mitochondrial fission. Among genes involved in mitochondrial dynamics, MFN1 is identified as a leading downregulated candidate that is closely associated with HCC metastasis and poor prognosis. While promoting mitochondrial fusion, MFN1 inhibits cell proliferation, invasion and migration capacity both in vitro and in vivo. Mechanistically, disruption of mitochondrial dynamics by depletion of MFN1 triggers the epithelial-to-mesenchymal transition (EMT) of HCC. Moreover, MFN1 modulates HCC metastasis by metabolic shift from aerobic glycolysis to oxidative phosphorylation. Treatment with glycolytic inhibitor 2-Deoxy-D-glucose (2-DG) significantly suppresses the effects induced by depletion of MFN1.
Our results reveal a critical involvement of mitochondrial dynamics in HCC metastasis via modulating glucose metabolic reprogramming. MFN1 may serve as a novel potential therapeutic target for HCC.
To explore whether plasma circular RNAs (circRNAs) can diagnose hepatitis B virus (HBV)‐related hepatocellular carcinoma (HCC), microarray and qPCR were used to identify plasma circRNAs that were ...increased in HBV‐related HCC patients compared to controls (including healthy controls, chronic hepatitis B and HBV‐related liver cirrhosis). A logistic regression model was constructed using a training set (n = 313) and then validated using another two independent sets (n = 306 and 526, respectively). Area under the receiver operating characteristic curve (AUC) was used to evaluate diagnostic accuracy. We identified a plasma circRNA panel (CircPanel) containing three circRNAs (hsa_circ_0000976, hsa_circ_0007750 and hsa_circ_0139897) that could detect HCC. CircPanel showed a higher accuracy than AFP (alpha‐fetoprotein) to distinguish individuals with HCC from controls in all three sets (AUC, 0.863 95% confidence interval, CI: 0.819–0.907 vs. 0.790 0.738–0.842, p = 0.036 in training set; 0.843 0.796–0.890 vs. 0.747 0.691–0.804, p = 0.011 in validation set 1 and 0.864 0.830–0.898 vs. 0.769 0.728–0.810, p < 0.001 in validation set 2). CircPanel also performed well in detecting Small‐HCC (solitary, ≤3 cm), AFP‐negative HCC and AFP‐negative Small‐HCC.
What's new?
To date, one limitation in the treatment of hepatocellular carcinoma (HCC) is the lack of serum biomarkers with satisfactory diagnostic accuracy. Here, the authors explored whether plasma circRNAs can be biomarkers to diagnose hepatitis B virus‐related HCC in 1155 participants from three hospitals in China. They identified a plasma circRNA panel (CircPanel, including hsa_circ_0000976, hsa_circ_0007750, and hsa_circ_0139897) that showed higher accuracy than the clinically‐used serum biomarker AFP in distinguishing individuals with HCC or Small‐HCC from controls and performed well in diagnosing AFP‐negative HCC and AFP‐negative Small‐HCC. Altogether, the findings point to CircPanel as a promising potential biomarker in HCC diagnosis.
In the tumour microenvironment, critical drivers of immune escape include the oncogenic activity of the tumour cell-intrinsic osteopontin (OPN), the expression of programmed death ligand 1 (PD-L1) ...and the expansion of tumour-associated macrophages (TAMs). We investigated the feasibility of targeting these pathways as a therapeutic option in hepatocellular carcinoma (HCC) mouse models.
We analysed the number of tumour-infiltrating immune cells and the inflammatory immune profiles in chemically induced liver tumour isolated from wild-type and
knockout (KO) mice. In vitro cell cocultures were further conducted to investigate the crosstalk between TAMs and HCC cells mediated by OPN, colony stimulating factor-1 (CSF1) and CSF1 receptor (CSF1R). The in vivo efficacy of anti-PD-L1 and CSF1/CSF1R inhibition was evaluated in OPN overexpressing subcutaneous or orthotopic mouse model of HCC.
The numbers of TAMs, as well as the expression levels of M2 macrophage markers and PD-L1 were significantly decreased, but the levels of cytokines produced by T-helper 1 (Th1) cells were upregulated in tumour tissues from OPN KO mice compared with that from the controls. In addition, we observed a positive association between the OPN and PD-L1 expression, and OPN expression and TAM infiltration in tumour tissues from patients with HCC. We further demonstrated that OPN facilitates chemotactic migration, and alternative activation of macrophages, and promotes the PD-L1 expression in HCC via activation of the CSF1-CSF1R pathway in macrophages. Combining anti-PD-L1 and CSF1R inhibition elicited potent antitumour activity and prolonged survival of OPN
tumour-bearing mice. Histological, flow cytometric and ELISA revealed increased CD8
T cell infiltration, reduced TAMs and enhanced Th1/Th2 cytokine balance in multiple mouse models of HCC.
OPN/CSF1/CSF1R axis plays a critical role in the immunosuppressive nature of the HCC microenvironment. Blocking CSF1/CSF1R prevents TAM trafficking and thereby enhances the efficacy of immune checkpoint inhibitors for the treatment of HCC.
Abstract
Disseminated tumor cells often fall into a long term of dormant stage, characterized by decreased proliferation but sustained survival, in distant organs before awakening for metastatic ...growth. However, the regulatory mechanism of metastatic dormancy and awakening is largely unknown. Here, we show that the epithelial-like and mesenchymal-like subpopulations of breast cancer stem-like cells (BCSCs) demonstrate different levels of dormancy and tumorigenicity in lungs. The long non-coding RNA (lncRNA)
NR2F1-AS1
(
NAS1
) is up-regulated in the dormant mesenchymal-like BCSCs, and functionally promotes tumor dissemination but reduces proliferation in lungs. Mechanistically,
NAS1
binds to
NR2F1
mRNA and recruits the RNA-binding protein PTBP1 to promote internal ribosome entry site (IRES)-mediated NR2F1 translation, thus leading to suppression of
ΔNp63
transcription by NR2F1. Furthermore, ΔNp63 downregulatio results in epithelial-mesenchymal transition, reduced tumorigenicity and enhanced dormancy of cancer cells in lungs. Overall, the study links BCSC plasticity with metastatic dormancy, and reveals the lncRNA as an important regulator of both processes.
Tumor‐associated macrophages (TAMs) are crucial components of the tumor microenvironment. They play vital roles in hepatocellular carcinoma (HCC) progression. However, the interactions between TAMs ...and HCC cells have not been fully characterized. In this study, TAMs were induced using human monocytic cell line THP‐1 cells in vitro to investigate their functions in HCC progression. S100 calcium‐binding protein A9 (S100A9), an inflammatory microenvironment‐related secreted protein, was identified to be significantly upregulated in TAMs. S100A9 expression in tumor tissues was associated with poor survival of HCC patients. It could enhance the stem cell‐like properties of HepG2 and MHCC‐97H cells by activating nuclear factor‐kappa B signaling pathway through advanced glycosylation end product‐specific receptor in a Ca2+‐dependent manner. Furthermore, we found that, after treatment with S100A9, HepG2 and MHCC‐97H cells recruited more macrophages via chemokine (CC motif) ligand 2, which suggests a positive feedback between TAMs and HCC cells. Taken together, our findings reveal that TAMs could upregulate secreted protein S100A9 and enhance the stem cell‐like properties of HCC cells and provide a potential therapeutic target for combating HCC.
What's new?
Prognosis of hepatocellular carcinoma (HCC) is influenced by tumor‐associated macrophages (TAMs) in the tumor microenvironment. Little is known, however, about how TAMs fuel HCC progression. This comparative analysis of RNA‐sequencing and whole‐genome expression profiling between TAMs and nonactivated M0 macrophages identified three common upregulated genes with potential impact on HCC prognosis. Among them, S100 calcium binding protein A9 (S100A9) was found to enhance stem cell‐like properties in HCC cells, via Ca2+‐dependent signaling along the AGER/NF‐κB axis. Moreover, S100A9 increased TAM infiltration by facilitating CCL2 secretion. The findings warrant further investigation of S100A9 secretion and enhanced HCC cell stemness by TAMs.
Down‐regulation of microRNA‐26a (miR‐26a) is associated with poor prognosis of hepatocellular carcinoma (HCC), but its functional mechanism in HCC remains unclear. In this study, we investigated the ...roles of miR‐26a in tumor growth and metastasis of HCC and found that miR‐26a was frequently down‐regulated in HCC tissues. Down‐regulation of miR‐26a correlated with HCC recurrence and metastasis. Through gain‐ and loss‐of‐function studies, miR‐26a was demonstrated to significantly inhibit in vitro cell proliferation, migration, and invasion. In addition, miR‐26a induced G1 arrest and promoted apoptosis of HCC cells. Importantly, miR‐26a suppressed in vivo tumor growth and metastasis in nude mice models bearing human HCC. Interleukin‐6 (IL‐6) was identified as a target of miR‐26a. Knockdown of IL‐6 induced effects on HCC cells similar to those induced by miR‐26a. In contrast, IL‐6 treatment abrogated the effects induced by miR‐26a up‐regulation. Moreover, miR‐26a dramatically suppressed expression of signal transducer and activator of transcription 3 (Stat3) target genes, including Bcl‐2, Mcl‐1, cyclin D1, and MMP2. IL‐6 treatment antagonized this effect, while knockdown of IL‐6 by IL‐6 short hairpin RNA (shIL‐6) induced inhibitory effects on the expression of p‐Stat3 and its main target genes, similar to miR‐26a. The messenger RNA and protein levels of IL‐6 inversely correlated with miR‐26a in HCCs. Patients with high miR‐26a or low IL‐6 in HCC tissues had a better prognosis with longer overall survival (OS) and time to recurrence (TTR). In multivariate analysis, miR‐26a, IL‐6, and their combination were demonstrated to be independent prognostic indicators for OS and TTR of HCC patients. Conclusion: miR‐26a could suppress tumor growth and metastasis of HCC through IL‐6‐Stat3 signaling and is a novel prognostic marker and therapeutic target for HCC. (HEPATOLOGY 2013)
Globally, hepatocellular carcinoma (HCC) accounts for 70%‐85% of primary liver cancers and ranks as the second leading cause of male cancer death. Serum alpha‐fetoprotein (AFP), normally highly ...expressed in the liver only during fetal development, is reactivated in 60% of HCC tumors and associated with poor patient outcome. We hypothesize that AFP+ and AFP− tumors differ biologically. Multivariable analysis in 237 HCC cases demonstrates that AFP level predicts poor survival independent of tumor stage (P < 0.043). Using microarray‐based global microRNA (miRNA) profiling, we found that miRNA‐29 (miR‐29) family members were the most significantly (P < 0.001) down‐regulated miRNAs in AFP+ tumors. Consistent with miR‐29's role in targeting DNA methyltransferase 3A (DNMT3A), a key enzyme regulating DNA methylation, we found a significant inverse correlation (P < 0.001) between miR‐29 and DNMT3A gene expression, suggesting that they might be functionally antagonistic. Moreover, global DNA methylation profiling reveals that AFP+ and AFP− HCC tumors have distinct global DNA methylation patterns and that increased DNA methylation is associated with AFP+ HCC. Experimentally, we found that AFP expression in AFP− HCC cells induces cell proliferation, migration, and invasion. Overexpression of AFP, or conditioned media from AFP+ cells, inhibits miR‐29a expression and induces DNMT3A expression in AFP− HCC cells. AFP also inhibited transcription of the miR‐29a/b‐1 locus, and this effect is mediated through c‐MYC binding to the transcript of miR‐29a/b‐1. Furthermore, AFP expression promotes tumor growth of AFP− HCC cells in nude mice. Conclusion: Tumor biology differs considerably between AFP+ HCC and AFP− HCC; AFP is a functional antagonist of miR‐29, which may contribute to global epigenetic alterations and poor prognosis in HCC. (Hepatology 2014;60:872–883)
Exosomes are a subset of extracellular vesicles that carry specific combinations of proteins, nucleic acids, metabolites, and lipids. Mounting evidence suggests that exosomes participate in ...intercellular communication and act as important molecular vehicles in the regulation of numerous physiological and pathological processes, including cancer development. Exosomes are released by various cell types under both normal and pathological conditions, and they can be found in multiple bodily fluids. Moreover, exosomes carrying a wide variety of important macromolecules provide a window into altered cellular or tissue states. Their presence in biological fluids renders them an attractive, minimally invasive approach for liquid biopsies with potential biomarkers for cancer diagnosis, prediction, and surveillance. Due to their biocompatibility and low immunogenicity and cytotoxicity, exosomes have potential clinical applications in the development of innovative therapeutic approaches. Here, we summarize recent advances in various technologies for exosome isolation for cancer research. We outline the functions of exosomes in regulating tumor metastasis, drug resistance, and immune modulation in the context of cancer development. Finally, we discuss prospects and challenges for the clinical development of exosome-based liquid biopsies and therapeutics.
The immunosuppressive microenvironment plays an important role in tumor progression and immunotherapy responses. Golgi membrane protein 1 (GOLM1) is correlated to hepatocellular carcinoma (HCC) ...progression and metastasis. However, little is known about the role of GOLM1 in regulating the immunosuppressive environment and its impact on immunotherapeutic efficacy in HCC. In this study, GOLM1 was positively correlated with infiltrating tumor-associated macrophages (TAMs) expressed high levels of programmed death-ligand 1 (PD-L1) and CD8
T cell suppression in HCC tissues. Both gain- and loss-of-function studies determined a close correlation between GOLM1 and immunosuppression. In the mechanism, GOLM1 promoted COP9 signalosome 5-mediated PD-L1 deubiquitination in HCC cells and increased the transport of PD-L1 into exosomes via suppression of Rab27b expression. Furthermore, co-culture with exosomes derived from HCC cells upregulated the expression of PD-L1 on macrophages. Zoledronic acid in combination with anti-PD-L1 therapy reduced PD-L1
TAMs infiltration and alleviated CD8
T cell suppression, resulting in tumor growth inhibition in the mouse HCC model. Together, our study unveils a mechanism by which GOLM1 induces CD8
T cells suppression through promoting PD-L1 stabilization and transporting PD-L1 into TAMs with exosome dependent. Targeting PD-L1
TAM could be a novel strategy to enhance the efficacy of anti-PD-L1 therapy in HCC.
MicroRNAs (miRNAs) have been used as cancer‐related biomarkers. Hepatocellular carcinoma (HCC) is an aggressive cancer with a dismal outcome largely due to metastasis and postsurgical recurrence. We ...investigated whether the expression of certain miRNAs are associated with HCC metastasis. We examined the miRNA expression profiles of 482 cancerous and noncancerous specimens from radical resection of 241 patients with HCC. Using a supervised algorithm and a clinically well‐defined cohort of 131 cases, we built a unique 20‐miRNA metastasis signature that could significantly predict (P < 0.001) primary HCC tissues with venous metastases from metastasis‐free solitary tumors with 10‐fold cross‐validation. However, significant miRNAs could not be identified from the corresponding noncancerous hepatic tissues. A survival risk prediction analysis revealed that a majority of the metastasis‐related miRNAs were associated with survival. Furthermore, the 20‐miRNA tumor signature was validated in 110 additional cases as a significant independent predictor of survival (P = 0.009) and was significantly associated with both survival and relapse in 89 cases of early stage HCC (P = 0.022 and 0.002, respectively). These 20 miRNAs may provide a simple profiling method to assist in identifying patients with HCC who are likely to develop metastases/recurrence. In addition, functional analysis of these miRNAs may enhance our biological understanding of HCC metastasis. (HEPATOLOGY 2008.)
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