Simultaneously targeting SOAT1 and CPT1A ameliorates hepatocellular carcinoma by disrupting lipid homeostasis

AbstractLipid homeostasis plays a fundamental role in the development of hepatocellular carcinoma (HCC). However, the mechanisms that regulate lipid homeostasis to avoid lipotoxicity in HCC remain elusive. Here, we found high-fat diet (HFD) improved the expression of sterol o-acyltransferase1 (SOAT1) and carnitine palmitoyltransferase 1A (CPT1A) in diethylnitrosamine-induced HCC. Bioinformatic analysis showed that SOAT1-mediated fatty acid storage and CPT1A-mediated fatty acids oxidation (FAO) formed a double-negative feedback loop in HCC. We verified that SOAT1 inhibition enhanced CPT1A protein, which shuttled the released fatty acids into the mitochondria for oxidation in vivo and in vitro. Besides, we further confirmed that CPT1A inhibition converted excess fatty acids into lipid drops by SOAT1 in vitro. Simultaneously targeting SOAT1 and CPT1A by the small-molecule inhibitors avasimibe and etomoxir had synergistic anticancer efficacy in HCC in vitro and in vivo. Our study provides new mechanistic insights into the regulation of lipid homeostasis and suggests the combination of avasimibe and etomoxir is a novel strategy for HCC treatment.

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CircMTO1 suppresses hepatocellular carcinoma progression via the miR-541-5p/ZIC1 axis by regulating Wnt/β-catenin signaling pathway and epithelial-to-mesenchymal transition

Cell Death and Disease ◽

10.1038/s41419-021-04464-3 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Dandan Li ◽

Jiawei Zhang ◽

Jing Yang ◽

Jie Wang ◽

Runling Zhang ◽

...

Keyword(s):

Hepatocellular Carcinoma ◽

Tumor Growth ◽

Epithelial To Mesenchymal Transition ◽

Bioinformatic Analysis ◽

Luciferase Reporter ◽

Migration And Invasion ◽

Signal Pathways ◽

Mesenchymal Transition

AbstractCircRNA mitochondrial tRNA translation optimization 1 (circMTO1) functions as a tumor suppressor usually and is related to the progression of many tumors, including hepatocellular carcinoma (HCC). CircMTO1 is downregulated in HCC as compared to adjacent nontumor tissue, which may suppress the HCC progression by certain signal pathways. However, the underlying signal pathway remains largely unknown. The interactions between circMTO1 and miR-541-5p were predicted through bioinformatics analysis and verified using pull-down and dual-luciferase reporter assays. CCK-8, transwell, and apoptosis assays were performed to determine the effect of miR-541-5p on HCC progression. Using bioinformatic analysis, dual-luciferase reporter assay, RT-qPCR, and western blot, ZIC1 was found to be the downstream target gene of miR-541-5p. The regulatory mechanisms of circMTO1, miR-541-5p, and ZIC1 were investigated using in vitro and in vivo rescue experiments. The results depicted that silencing circMTO1 or upregulating miR-541-5p expression facilitated HCC cell proliferation, migration, and invasion and inhibited apoptosis. CircMTO1 silencing upregulated the expression of downstream ZIC1 regulators of the Wnt/β-catenin pathway markers, β-catenin, cyclin D1, c-myc, and the mesenchymal markers N-cadherin, Vimentin, and MMP2, while the epithelial marker E-cadherin was downregulated. MiR-541-5p knockdown had the opposite effect and reversed the effect of circMTO1 silencing on the regulation of downstream ZIC1 regulators. Intratumoral injection of miR-541-5p inhibitor suppressed tumor growth and reversed the effect of circMTO1 silencing on the promotion of tumor growth in HCC. These findings indicated that circMTO1 suppressed HCC progression via the circMTO1/ miR-541-5p/ZIC1 axis by regulating Wnt/β-catenin signaling and epithelial-to-mesenchymal transition, making it a novel therapeutic target.

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β-TrCP-mediated ubiquitination and degradation of Dlg5 regulates hepatocellular carcinoma cell proliferation

Cancer Cell International ◽

10.1186/s12935-019-1029-1 ◽

2019 ◽

Vol 19 (1) ◽

Cited By ~ 1

Author(s):

Dongping Wang ◽

Qi Zhang ◽

Fenfen Li ◽

Chan Wang ◽

Changming Yang ◽

...

Keyword(s):

Hepatocellular Carcinoma ◽

Xenograft Model ◽

Ubiquitin Proteasome System ◽

Tumor Xenograft ◽

Dependent Manner ◽

Ubiquitin Proteasome ◽

Novel Strategy ◽

Hcc Cells

Abstract Background Discs large homolog 5 (Dlg5) is a member of the membrane-associated guanylate kinase (MAGUK) adaptor family of proteins and its deregulation has been implicated in the malignancy of several cancer types. Dlg5 was down-regulated in hepatocellular carcinoma (HCC) and lower Dlg5 expression was associated with poor survival of HCC patients. However, how to regulate Dlg5 remains largely unknown. Methods The co-immunoprecipitation assay was used to determine the interaction between Dlg5 and β-TrCP. The in vivo ubiquitination assay was performed to determine the regulation of Dlg5 by β-TrCP. CCK-8 and colony formation assay were implemented to detect the biological effect of Dlg5 on the growth of HCC cells in vitro. The effect of Dlg5 on HCC tumor growth in vivo was studied in a tumor xenograft model in mice. Results Here we report that Dlg5 is regulated by the ubiquitin proteasome system and depletion of either Cullin 1 or β-TrCP led to increased levels of Dlg5. β-TrCP regulated Dlg5 protein stability by targeting it for ubiquitination and subsequent destruction in a phosphorylation-dependent manner. We further demonstrated a crucial role of Ser730 in the non-canonical phosphodegron of Dlg5 in governing β-TrCP-mediated Dlg5 degradation. Importantly, failure to degrade Dlg5 significantly inhibited HCC cells proliferation both in vitro and in vivo. Conclusion Collectively, our finding provides a novel molecular mechanism for the negative regulation of Dlg5 by β-TRCP in HCC cells. It further suggests that preventing Dlg5 degradation could be a possible novel strategy for clinical treatment of HCC.

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Investigation of in vivo fatty acid metabolism in AFABP/aP2−/− mice

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00256.2004 ◽

2005 ◽

Vol 288 (1) ◽

pp. E187-E193 ◽

Cited By ~ 63

Author(s):

Rachel A. Baar ◽

Carlus S. Dingfelder ◽

Lisa A. Smith ◽

David A. Bernlohr ◽

Chaodong Wu ◽

...

Keyword(s):

Fatty Acids ◽

Fatty Acid ◽

High Fat Diet ◽

Nonesterified Fatty Acid ◽

Fatty Acid Binding ◽

Fed State ◽

Meal Feeding

The metabolic impact of the murine adipocyte fatty acid-binding protein (AFABP/aP2) on lipid metabolism was investigated in the AFABP/aP2−/− mouse and compared with wild-type C57BL/6J littermates. Mice were weaned on a high-fat diet (59% of energy from fat) and acclimated to meal feeding. Stable isotopes were administered, and indirect calorimetry was performed to quantitate fatty acid flux, dietary fatty acid utilization, and substrate oxidation. Consistent with previous in situ and in vitro studies, fasting serum nonesterified fatty acid (NEFA) release was significantly reduced in AFABP/aP2−/− (17.1 ± 9.0 vs. 51.9 ± 22.9 mg·kg−1·min−1). AFABP/aP2−/− exhibited higher serum NEFA (1.4 ± 0.6 vs. 0.8 ± 0.4 mmol/l, AFABP/aP2−/− vs. C57BL/6J, respectively) and triacylglycerol (TAG; 0.23 ± 0.09 vs. 0.13 ± 0.10 mmol/l) and accumulated more TAG in liver tissue (2.9 ± 2.3 vs. 1.1 ± 0.8% wet wt) in the fasted state. For the liver-TAG pool, 16.4 ± 7.3% of TAG-fatty acids were derived from serum NEFA in AFABP/aP2−/−. In contrast, a significantly greater portion of C57BL/6J liver-TAG was derived from serum NEFA (42.3 ± 25.5%) during tracer infusion. For adipose-TAG stores, only 0.29 ± 0.04% was derived from serum NEFA in AFABP/aP2−/−, and, in C57BL/6J, 1.85 ± 0.97% of adipose-TAG was derived from NEFA. In addition, AFABP/aP2−/− preferentially oxidized glucose relative to fatty acids in the fed state. These data demonstrate that in vivo disruption of AFABP/aP2−/− leads to changes in the following two major metabolic processes: 1) decreased adipose NEFA efflux and 2) preferential utilization of glucose relative to fatty acids.

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Naa20, the catalytic subunit of NatB complex, contributes to hepatocellular carcinoma by regulating the LKB1–AMPK–mTOR axis

Experimental & Molecular Medicine ◽

10.1038/s12276-020-00525-3 ◽

2020 ◽

Vol 52 (11) ◽

pp. 1831-1844

Author(s):

Taek-Yeol Jung ◽

Jae-Eun Ryu ◽

Mi-Mi Jang ◽

Soh-Yeon Lee ◽

Gyu-Rin Jin ◽

...

Keyword(s):

Hepatocellular Carcinoma ◽

Signaling Pathway ◽

Mammalian Target Of Rapamycin ◽

Underlying Mechanism ◽

Bioinformatic Analysis ◽

Catalytic Subunit ◽

The Cancer Genome Atlas ◽

Ampk Activity

AbstractN-α-acetyltransferase 20 (Naa20), which is a catalytic subunit of the N-terminal acetyltransferase B (NatB) complex, has recently been reported to be implicated in hepatocellular carcinoma (HCC) progression and autophagy, but the underlying mechanism remains unclear. Here, we report that based on bioinformatic analysis of Gene Expression Omnibus and The Cancer Genome Atlas data sets, Naa20 expression is much higher in HCC tumors than in normal tissues, promoting oncogenic properties in HCC cells. Mechanistically, Naa20 inhibits the activity of AMP-activated protein kinase (AMPK) to promote the mammalian target of rapamycin signaling pathway, which contributes to cell proliferation, as well as autophagy, through its N-terminal acetyltransferase (NAT) activity. We further show that liver kinase B1 (LKB1), a major regulator of AMPK activity, can be N-terminally acetylated by NatB in vitro, but also probably by NatB and/or other members of the NAT family in vivo, which may have a negative effect on AMPK activity through downregulation of LKB1 phosphorylation at S428. Indeed, p-LKB1 (S428) and p-AMPK levels are enhanced in Naa20-deficient cells, as well as in cells expressing the nonacetylated LKB1-MPE mutant; moreover, importantly, LKB1 deficiency reverses the molecular and cellular events driven by Naa20 knockdown. Taken together, our findings suggest that N-terminal acetylation of LKB1 by Naa20 may inhibit the LKB1–AMPK signaling pathway, which contributes to tumorigenesis and autophagy in HCC.

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DNMT1-induced miR-378a-3p silencing promotes angiogenesis via the NF-κB signaling pathway by targeting TRAF1 in hepatocellular carcinoma

Journal of Experimental & Clinical Cancer Research ◽

10.1186/s13046-021-02110-6 ◽

2021 ◽

Vol 40 (1) ◽

Author(s):

Bin Zhu ◽

Jun-Jie Chen ◽

Ying Feng ◽

Jun-Ling Yang ◽

Hua Huang ◽

...

Keyword(s):

Hepatocellular Carcinoma ◽

Positive Feedback ◽

Dna Methyltransferase ◽

Feedback Loop ◽

Tube Formation ◽

Cell Counting ◽

Luciferase Reporter ◽

Positive Feedback Loop

Abstract Background Angiogenesis plays an important role in the occurrence, development and metastasis of hepatocellular carcinoma (HCC). According to previous studies, miR-378a participates in tumorigenesis and tumor metastasis, but its exact role in HCC angiogenesis remains poorly understood. Methods qRT-PCR was used to investigate the expression of miR-378a-3p in HCC tissues and cell lines. The effects of miR-378a-3p on HCC in vitro and in vivo were examined by Cell Counting Kit-8 (CCK-8), Transwell, tube formation and Matrigel plug assays, RNA sequencing, bioinformatics, luciferase reporter, immunofluorescence and chromatin immunoprecipitation (ChIP) assays were used to detect the molecular mechanism by which miR-378a-3p inhibits angiogenesis. Results We confirmed that miR-378a-3p expression was significantly downregulated and associated with higher microvascular density (MVD) in HCC; miR-378a-3p downregulation indicated a short survival time in HCC patients. miR-378a-3p knockdown led to a significant increase in angiogenesis in vitro and in vivo. We found that miR-378a-3p directly targeted TNF receptor associated factor 1 (TRAF1) to attenuate NF-κB signaling, and then downregulated secreted vascular endothelial growth factor. DNA methyltransferase 1 (DNMT1)-mediated hypermethylation of miR-378a-3p was responsible for downregulating miR-378a-3p. Moreover, a series of investigations indicated that p65 initiated a positive feedback loop that could upregulate DNMT1 to promote hypermethylation of the miR-378a-3p promoter. Conclusion Our study indicates a novel DNMT1/miR-378a-3p/TRAF1/NF-κB positive feedback loop in HCC cells, which may become a potential therapeutic target for HCC.

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The peroxisomal transporter ABCD3 plays a major role in dicarboxylic fatty acid metabolism

10.1101/2021.07.26.452046 ◽

2021 ◽

Author(s):

Pablo Ranea-Robles ◽

Hongjie Chen ◽

Brandon Stauffer ◽

Chunli Yu ◽

Dipankar Bhattacharya ◽

...

Keyword(s):

Fatty Acids ◽

De Novo ◽

Ketone Bodies ◽

De Novo Lipogenesis ◽

Lipid Homeostasis ◽

Hepatic Cholesterol Synthesis ◽

Specific Subset

Peroxisomes metabolize a specific subset of fatty acids, which include dicarboxylic fatty acids (DCAs) generated by ω-oxidation. Data obtained in vitro suggest that the peroxisomal transporter ABCD3 (also known as PMP70) mediates the transport of DCAs into the peroxisome, but in vivo evidence to support this role is lacking. In this study, we studied an Abcd3 KO mouse model generated by CRISPR-Cas9 technology using targeted and untargeted metabolomics, histology, immunoblotting, and stable isotope tracing technology. We show that ABCD3 functions in DCA metabolism and uncover a novel role for this peroxisomal transporter in lipid metabolic homeostasis. The Abcd3 KO mouse presents with lipodystrophy, increased circulating free fatty acids, decreased ketone bodies, enhanced hepatic cholesterol synthesis and decreased hepatic de novo lipogenesis. Moreover, our study suggests that DCAs are metabolized by mitochondrial β-oxidation when ABCD3 is not functional, reflecting the importance of the metabolic compartmentalization and communication between peroxisomes and mitochondria. In summary, this study provides data on the role of the peroxisomal transporter ABCD3 in hepatic lipid homeostasis and DCA metabolism, and the consequences of peroxisomal dysfunction for the liver.

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ω-6 Polyunsaturated fatty acids (linoleic acid) activate both autophagy and antioxidation in a synergistic feedback loop via TOR-dependent and TOR-independent signaling pathways

Cell Death and Disease ◽

10.1038/s41419-020-02750-0 ◽

2020 ◽

Vol 11 (7) ◽

Cited By ~ 1

Author(s):

Bo Yang ◽

Yan Zhou ◽

Mengjiao Wu ◽

Xueshan Li ◽

Kangsen Mai ◽

...

Keyword(s):

Fatty Acids ◽

Linoleic Acid ◽

Polyunsaturated Fatty Acids ◽

Signaling Pathway ◽

Antioxidant System ◽

Feedback Loop ◽

Molecular Mechanisms ◽

Antioxidant Ability

Abstract ω-6 Polyunsaturated fatty acids (PUFAs) are essential fatty acids that participate in macroautophagy (hereafter referred to as autophagy) and the Kelch ECH-associating protein 1 (Keap1)—nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant system in organisms. However, the molecular mechanisms by which ω-6 PUFAs (linoleic acid) regulate autophagy and Keap1–Nrf2 antioxidant system are not completely understood. Therefore, the purposes of this study were to explore the molecular mechanisms by which ω-6 PUFAs (linoleic acid) regulate autophagy and antioxidant system and to investigate the potential relationship between autophagy and antioxidant system through transcriptomic analysis, quantitative real-time polymerase chain reaction (RT-qPCR), western blot analysis, coimmunoprecipitation (Co-IP) and electrophoretic mobility shift assays (EMSAs) in vivo and in vitro. The results of the present study indicated that ω-6 PUFAs in diets induced autophagy but decrease antioxidant ability in vivo. However, the results also provided evidence, for the first time, that ω-6 PUFAs (linoleic acid) induced autophagy and increased antioxidant ability through the adenosine monophosphate-activated protein kinase (AMPK) signaling pathway and the AMPK-target of rapamycin (TOR) signaling pathway in hepatocytes in vitro. Interestingly, the findings revealed a ω-6 PUFA-induced synergistic feedback loop between autophagy and antioxidant system, which are connected with each other through the P62 and Keap1 complex. These results suggested that ω-6 PUFAs (linoleic acid) could be useful for activating a synergistic feedback loop between autophagy and antioxidant system and could greatly aid in the prevention and treatment of multiple pathologies.

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pH-responsive delivery vehicle based on RGD-modified polydopamine-paclitaxel-loaded poly (3-hydroxybutyrate-co-3-hydroxyvalerate) nanoparticles for targeted therapy in hepatocellular carcinoma

Journal of Nanobiotechnology ◽

10.1186/s12951-021-00783-x ◽

2021 ◽

Vol 19 (1) ◽

Author(s):

Mingfang Wu ◽

Chen Zhong ◽

Qian Zhang ◽

Lu Wang ◽

Lingling Wang ◽

...

Keyword(s):

Hepatocellular Carcinoma ◽

Scanning Calorimetry ◽

Anticancer Efficacy ◽

Coated Nanoparticles ◽

Transmission Electron ◽

Sensitive Coating ◽

Arginine Glycine Aspartic Acid ◽

The Michael Addition

AbstractA limitation of current anticancer nanocarriers is the contradiction between multiple functions and favorable biocompatibility. Thus, we aimed to develop a compatible drug delivery system loaded with paclitaxel (PTX) for hepatocellular carcinoma (HCC) therapy. A basic backbone, PTX-loaded poly (3-hydroxybutyrate-co-3-hydroxyvalerate) PHBV nanoparticle (PHBV-PTX-NPs), was prepared by emulsion solvent evaporation. As a gatekeeper, the pH-sensitive coating was formed by self-polymerization of dopamine (PDA). The HCC-targeted arginine-glycine-aspartic acid (RGD)-peptide and PDA-coated nanoparticles (NPs) were combined through the Michael addition. Subsequently, the physicochemical properties of RGD-PDA-PHBV-PTX-NPs were characterized by dynamic light scattering-autosizer, transmission electron microscope, fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetry and X-ray spectroscopy. As expected, the RGD-PDA-PHBV-PTX-NPs showed robust anticancer efficacy in a xenograft mouse model. More importantly, they exhibited lower toxicity than PTX to normal hepatocytes and mouse in vitro and in vivo, respectively. Taken together, these results indicate that the RGD-PDA-PHBV-PTX-NPs are potentially beneficial for easing conflict between multifunction and biocompatible characters of nanocarriers.

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CircC16orf62 promotes hepatocellular carcinoma progression through the miR-138-5p/PTK2/AKT axis

Cell Death and Disease ◽

10.1038/s41419-021-03866-7 ◽

2021 ◽

Vol 12 (6) ◽

Author(s):

Shuai Zhang ◽

Yuan Lu ◽

Hong-Yu Jiang ◽

Zhi-Mei Cheng ◽

Zi-Jing Wei ◽

...

Keyword(s):

Hepatocellular Carcinoma ◽

Predictive Marker ◽

Bioinformatic Analysis ◽

Circular Rna ◽

Mtor Pathway ◽

Loss Of Function ◽

Downstream Target ◽

Competitive Endogenous Rna

AbstractCircular RNA (circRNAs) functions vital in the pathogenesis and progression of hepatocellular carcinoma (HCC). However, the expressions and functions of certain circRNAs on metastasis and proliferation of that cancer is still unclear. Bioinformation analysis and qRT-PCR indicated that CircC16orf62 was prominent upregulated in HCC of which the expression level was positively associated to cancer’s malignant progression. Gain or loss-of-function studies indicated that the reduction of CircC16orf62 expression promotes the proliferation, invasion, and glycolysis of HCC in vitro and in vivo. The bioinformatic analysis found that miR-138-5p and PTK2 were the downstream target of CircC16or62. Then, the FISH(Fluorescence immunoin situ hybridization) and cell nucleoplasmic separation determined that CircC16orf62 located in the cell cytoplasm. Plasmid vectors or siRNAs were used to change the expression of CircC16orf62, miR-138-5p, and PTK2 in PC cell lines. CircC16orf62 functioned as a molecular sponge for miR-138-5p, and a competitive endogenous RNA for PTK2, promoting AKT/mTOR pathway activation. Our observations lead us to conclude that CircC16orf62 functions as an oncogene in HCC progression, behaving as a competitive endogenous RNA for miR-138-5p binding, thus activating the AKT/mTOR pathway. In conclusion, CircC16orf62 is an oncogene through the miR-138-5p/PTK2/Akt axis in HCC cells, indicating CircC16orf62 can be a therapeutic target with potentiality for liver cancer and a predictive marker for people with HCC.

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MT1JP-mediated miR-24-3p/BCL2L2 axis promotes Lenvatinib resistance in hepatocellular carcinoma cells by inhibiting apoptosis

Cellular Oncology ◽

10.1007/s13402-021-00605-0 ◽

2021 ◽

Author(s):

Ting Yu ◽

Jiajian Yu ◽

Lu Lu ◽

Yize Zhang ◽

Yadong Zhou ◽

...

Keyword(s):

Hepatocellular Carcinoma ◽

Feedback Loop ◽

Carcinoma Cells ◽

Advanced Hepatocellular Carcinoma ◽

Apoptotic Protein ◽

Non Coding Rnas ◽

Hcc Cells

Abstract Purpose Lenvatinib is a long-awaited alternative to Sorafenib for first-line targeted therapy of patients with advanced hepatocellular carcinoma (HCC). However, resistance to Lenvatinib results in tumor progression and has become a major obstacle to improving the prognosis of HCC patients. Exploring the mechanisms underlying Lenvatinib resistance is considered essential for the treatment of advanced HCC. Methods Lenvatinib resistant HCC (LR-HCC) cells were generated and potential long non-coding RNAs (Lnc-RNAs) upregulated in LR-HCC cells were identified by RNA sequencing. The effects of upregulated Lnc-RNAs were evaluated in vitro in cell models and in vivo in experimental animals using quantitative cell viability and apoptosis assays. Results We found that Lnc-RNA MT1JP (MT1JP) was upregulated in LR-HCC cells and inhibited the apoptosis signaling pathway. In addition, we found that sponging of microRNA-24-3p by MT1JP released Bcl-2 like 2 (BCL2L2), an anti-apoptotic protein, thereby forming a positive-feedback loop. The role of this feedback loop was validated using rescue assays. Additionally, we found that upregulation of MT1JP and BCL2L2 impaired the sensitivity of HCC cells to Lenvatinib both vitro and vivo. Conclusions Our results suggest a novel molecular feedback loop between MT1JP and apoptosis signaling in Lenvatinib sensitive HCC cells.

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