Hepatocellular carcinoma serum derived exosomal HIF-1α induces phosphoinositide-3 kinase/protein kinase B signaling to induce the angiogenesis and proliferation of HCC.
Tumor exosomes are nanovesicles mostly secreted by tumor cells that play roles of paracrine signaling during tumor progression, including tumor-stromal interactions, activation of proliferative pathways and inducing immunosuppression. The hypoxia-inducible factor (HIF) family serve role of the principal molecular mediators of hypoxia in physiological and pathophysiological course. HIF-1α excreted from tumor and stromal cells serves an important role in tumor angiogenesis, especially in hepatocellular carcinoma (HCC). However, exosomal HIF-1α from HCC serum has not been studied extensively. The present study aimed to determine role of HIF-1α derived from HCC serum exosomes in the development of HCC.
We extracted exosomes from the serum of 48 patients suffering HCC and 24 healthy individuals. The exosomes were examined by transmission electron microscopy and nanoparticle tracking analysis. The concentrations of exosomal HIF-1α were measured by ELISA. In vitro experiments were performed to testify the exosomal role in human umbilical endothelial cells (HUVECs) and Huh-7 cells by tube formation, cell viability and western blotting analyses. Nude mouse xenograft Huh-7 tumors were generated by injecting HCC patient serum exosomes, healthy individuals' serum exosomes and PBS into nude mice. Tumors in vivo were isolated, weighed and subjected to immunohistochemical assays.
HCC patients exhibited a greater capacity to convert HIF-1α in serum exosomes than normal individuals (P=0.0007), and high serum exosomal HIF-1α levels were correlated with Barcelona Clinic Liver Cancer (BCLC) staging (P=0.031) and the phosphoinositide-3 kinase (PI3K)/protein kinase B (AKT) signaling pathway. The results of flow cytometry analysis demonstrated that the HUVECs cocultured with HCC exosomes turned down the percentage of HUVECs in the G1 phase but turned up the percentage of HUVECs in the S phase (P<0.05). HUVECs and Huh-7 cells cultured with HCC serum exosomes enhanced the proliferation of HUVECs and Huh-7 cells, and the tube formation of HUVECs, while exosomes from healthy individuals and the controls did not. The results demonstrated that serum exosomes from patients with HCC appeared to accelerate tumor growth compared to the control group (P<0.05) and immunohistochemical analysis revealed that the nude mice injected with exosomes from HCC patient serum exhibited higher microvessel density (MVD) (P<0.05).
HCC serum derived exosomes could induce angiogenesis and the proliferation of HCC potentially via the HIF-1α-PI3K/AKT signaling pathway, it making the prevention and treatment of HCC angiogenesis and proliferation available.
Xu Q
，You R
，Yin G
，Gu J
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Exosomal HMGB1 derived from hypoxia-conditioned bone marrow mesenchymal stem cells increases angiogenesis via the JNK/HIF-1α pathway.
Mesenchymal stem cells (MSCs) have been described to induce angiogenesis in various tissues and have been used for the development of novel cell-based therapies. Increasing evidence suggests that MSCs execute their paracrine function via the secretion of exosomes, especially under hypoxic conditions. However, the mechanisms by which MSC-derived exosomes secreted under hypoxia enhance angiogenesis still remain unclear. To study exosome physiology under hypoxic or normoxic conditions, we isolated exosomes from bone marrow mesenchymal stem cells (BMSCs). Furthermore, we detected the uptake of exosomes by human umbilical vein endothelial cells (HUVECs) by immunofluorescence staining. In addition, we determined the effects of exosomes on cell viability, migration and tube formation in HUVECs by Cell Counting Kit-8, migration and tube formation assays, respectively. We examined the expression of key proteins related to exosome-induced angiogenesis by BMSCs cultured under hypoxic conditions by western blot. Exosomes released by BMSCs cultured under hypoxic conditions enhanced cell proliferation, migration and angiogenesis of HUVECs. Hypoxia induced the expression of high mobility group box 1 protein (HMGB1) in BMSC-derived exosomes, and silencing of HMGB1 abolished the angiogenic effect in HUVECs. Furthermore, exosomal HMGB1 activated the JNK signaling pathway and induced hypoxia-inducible factor-1α/vascular endothelial growth factor expression, consequently enhancing angiogenesis in HUVECs. Our data reveal that exosomal HMGB1 promotes angiogenesis via JNK/hypoxia-inducible factor-1α signaling. Therefore, BMSC exosomes derived under hypoxia may have potential for development of novel treatment strategies for angiogenesis-related diseases.
Gao W
，He R
，Ren J
，Zhang W
，Wang K
，Zhu L
，Liang T
... -
《FEBS Open Bio》
The epigallocatechin gallate derivative Y(6) inhibits human hepatocellular carcinoma by inhibiting angiogenesis in MAPK/ERK1/2 and PI3K/AKT/ HIF-1α/VEGF dependent pathways.
Hypervascularity has been considered as one of the major features of many solid tumors. Green tea is one of the commonly drink resources in China, and its active component, Epigallocatechin gallate (EGCG), exhibits antiangiogenic activities in various experimental tumor models. However, EGCG has many shortages, e.g., relatively unstable, low lipid solubility, poor bioavailability, and short duration of action.
To overcome the shortages of EGCG for antiangiogenic antitumor usage, our study developed a novel EGCG derivate, Y6(5,3',4',3″,4″,5″-6-0-ethyl-EGCG). The underlying mechanism was also elucidated.
we evaluated the effects of EGCG, Y6 on HCC and angiogenesis in vivo and in vitro. Moreover, to understand their antitumor mechanisms, key factors within angiogenesis-related signaling pathways (MAPK/ERK1/2, PI3K/AKT, HIF-1 VEGF) were analyzed by using western blot, immunohistochemistry (IHC), quantitative real-time quantitative PCR (RT-PCR). HepG2 xenograft model and the chorioallantoic membrane (CAM) were used to investigate the effects of Y6 and EGCG on tumors and anti-angiogenesis in vivo. Micro-vessel density (MVD) was analyzed by IHC of CD34 staining. IHC, qRT-PCR and Western blot were used to detect the expression of HIF-1α and VEGF protein in tumor tissues. The protein levels of MAPK/ERK1/2, PI3K/AKT, HIF-1α, and VEGF in tumor tissues were detected by western blot.
Our results demonstrated that both EGCG and Y6 displayed antiangiogenetic and antitumor effects against HCC cells in vitro and in vivo. We found that rather than equal amount of EGCG, Y6 displayed better abilities in inhibiting the growth of HCC tumor cells, as well as inhibiting the growth of neovascularization in the chick embryos and HepG2 xenograft tumors bearing-mice, based on the data obtained from MTT assay, immunohistochemistry (IHC), chick chorioallantoic membrane (CAM) assays. In the comparison of equivalent dose of EGCG, qRT-PCR data showed that Y6 induced more significant decrease of the mRNA levels of HIF-1α and VEGF in supernatant-treated SMMC-7721 cells under hypoxic condition, as well as in the in xenograft tumor tissues; whereas Y6 also significantly reduced the protein levels of MAPK/ERK1/2, PI3K/AKT, HIF-1α, and VEGF to a greater extent than EGCG, determined by western blotting assay.
our work suggests that the new EGCG derivate Y6 could significantly inhibit tumor growth and angiogenesis which is possibly involved with the signaling intervention of MAPK/ERK1/2 and PI3K/AKT/HIF-1α/VEGF pathways, and is supposed to be a potential therapeutic reagent for anti-angiogenesis treatment of solid tumors.
Liao ZH
，Zhu HQ
，Chen YY
，Chen RL
，Fu LX
，Li L
，Zhou H
，Zhou JL
，Liang G
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ResearchGate
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钛学术
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