Rab GTPases are major mediators that ensure the proper spatiotemporal regulation of intracellular trafficking. Functional impairment and altered expression of Rab proteins have been revealed in ...various human cancers. There is an emerging evidence about the role of Rab proteins in the biogenesis of extracellular vesicles (EVs). In hepatocellular carcinoma (HCC), using RNA sequencing comparing expression profiles of adjacent non‐tumorous tissues and HCC, Rab20 is identified to be the most frequently downregulated Rab member in HCC. Functionally, restoration of Rab20 in metastatic HCC cells results in the release of EVs with a diminished activity to promote cell growth, motility and metastasis. Conversely, EVs released from normal liver cells with Rab20 knockdown loses suppressive effect on HCC cell growth and motility. Proteomic profiling revealed the level of triosephosphate isomerase 1 (TPI1), a glycolytic enzyme, in EVs to be positively associated with Rab20 expression of the releasing cells. TPI1 targeted to be expressed in EVs released by Rab20 knockdown cells compromises the oncogenic activity of EVs. Besides, EVs released by TPI1 knockdown cells recapitulates the promoting effect of EVs derived from HCC cells with Rab20 underexpression. Aerobic glycolysis is beneficial to the survival and proliferation of tumour cells. Here, we observed that the enhanced cell growth and motility are driven by the enhanced aerobic glycolysis induced by EVs with reduced TPI1. The addition of glycolytic inhibitor blocks the promoting effect of EVs with reduced TPI1. Taken together, our study provides a mechanistic link among tumour cell‐derived EVs and glucose metabolism in HCC with Rab20 deregulation.
Lymph node metastasis is the most reliable indicator of a poor prognosis for patients with oral tongue cancers. Currently, there are no biomarkers to predict whether a cancer will spread in the ...future if it has not already spread at the time of diagnosis. The aim of this study was to quantitatively profile the proteomes of extracellular vesicles (EVs) isolated from blood samples taken from patients with oral tongue squamous cell carcinoma with and without lymph node involvement and non-cancer controls. EVs were enriched using size exclusion chromatography (SEC) from pooled plasma samples of patients with non-nodal and nodal oral tongue squamous cell carcinoma (OTSCC) and non-cancer controls. Protein cargo was quantitatively profiled using isobaric labelling (iTRAQ) and two-dimensional high-performance liquid chromatography followed by tandem mass spectrometry. We identified 208 EV associated proteins and, after filtering, generated a short list of 136 proteins. Over 85% of the EV-associated proteins were associated with the GO cellular compartment term “extracellular exosome”. Comparisons between non-cancer controls and oral tongue squamous cell carcinoma with and without lymph node involvement revealed 43 unique candidate EV-associated proteins with deregulated expression patterns. The shortlisted EV associated proteins described here may be useful discriminatory biomarkers for differentiating OTSCC with and without nodal disease or non-cancer controls.
Early diagnosis and treatment do not prevent the high morbidity and poor prognosis of oral tongue squamous cell carcinoma (TSCC). Earlier studies have shown that ARG1 signaling is deregulated in ...TSCC. Here, we investigated the complexity of ARG1 metabolism in this cancer subsite to appreciate the therapeutic potential of this potential biological vulnerability. Various functional studies show that ARG1 overexpression in oral cancer cells inhibits cell proliferation and invasion compared with controls. Further, RNA-sequencing revealed numerous differentially expressed genes (DEGs) and associated networks were dysregulated by ARG1 overexpression, including hypoxia-inducible factor (HIFα) signaling, the natural killer cell signaling pathway and interferon signaling. Our work provides a foundation for understanding the mechanism of action of disrupted arginine metabolism in oral tongue squamous cell carcinoma. This may impact the community for developing further therapeutic approaches.
Small extracellular vesicles (sEVs) play a key role in exchanging cargoes between cells in tumour microenvironment. This study aimed to elucidate the functions and mechanisms of hepatocellular ...carcinoma (HCC) derived sEV‐clathrin light chain A (CLTA) in remodelling microvascular niche. CLTA level in the circulating sEVs of HCC patients was analysed by enzyme‐linked immunosorbent assay (ELISA). The functions of sEV‐CLTA in affecting HCC cancerous properties were examined by multiple functional assays. Mass spectrometry was used to identify downstream effectors of sEV‐CLTA in human umbilical vein endothelial cells (HUVECs). Tube formation, sprouting, trans‐endothelial invasion and vascular leakiness assays were performed to determine the functions of sEV‐CLTA and its effector, basigin (BSG) in HUVECs. BSG inhibitor, SP‐8356, was tested in a mouse model of patient‐derived xenografts (PDXs). Circulating sEVs of HCC patients had markedly enhanced CLTA levels than control individuals and were reduced in patients after surgery. HCC derived sEV‐CLTA enhanced HCC cancerous properties, disrupted endothelial integrity and induced angiogenesis. Mechanistically, CLTA remodels microvascular niche by stabilizing and upregulating BSG. Last, SP‐8356 alone or in combination with sorafenib attenuated PDXs growth. The study reveals the role of HCC derived sEV‐CLTA in microvascular niche formation. Inhibition of CLTA and its mediated pathway may illuminate a new therapeutic strategy for HCC patients.
Extracellular vesicles (EVs) play a pivotal role in connecting tumor cells with their local and distant microenvironments. Herein, we aimed to understand the role (on a molecular basis) ...patient-derived EVs play in modulating cancer stemness and tumorigenesis in the context of hepatocellular carcinoma (HCC).
EVs from patient sera were isolated, quantified and characterized. The EVs were vigorously tested, both in vitro and in vivo, through various functional assays. Proteomic analysis was performed to identify the functional components of EVs. The presence and level of polymeric immunoglobulin receptor (pIgR) in circulating EVs and tumor and non-tumorous tissues of patients with HCC were determined by ELISA, immunoblotting, immunohistochemistry and quantitative PCR. The functional role and underlying mechanism of EVs with enhanced pIgR expression were elucidated. Blockade of EV-pIgR with neutralizing antibody was performed in nude mice implanted with patient-derived tumor xenografts (PDTXs).
Circulating EVs from patients with late-stage HCC (L-HCC) had significantly elevated pIgR expression compared to the EVs released by control individuals. The augmenting effect of L–HCC–EVs on cancer stemness and tumorigenesis was hindered by an anti-pIgR antibody. EVs enriched with pIgR consistently promoted cancer stemness and cancerous phenotypes in recipient cells. Mechanistically, EV-pIgR-induced cancer aggressiveness was abrogated by Akt and β-catenin inhibitors, confirming that the role of EV-pIgR depends on the activation of the PDK1/Akt/GSK3β/β-catenin signaling axis. Furthermore, an anti-pIgR neutralizing antibody attenuated tumor growth in mice implanted with PDTXs.
This study illustrates a previously unknown role of EV-pIgR in regulating cancer stemness and aggressiveness: EV-pIgR activates PDK1/Akt/GSK3β/β-catenin signaling cascades. The blockade of the intercellular communication mediated by EV-pIgR in the tumor microenvironment may provide a new therapeutic strategy for patients with cancer.
The World Health Organization estimates that more than 1 million patients will die from liver cancer, mostly hepatocellular carcinoma (HCC), in 2030. Understanding the underlying mechanism by which HCC acquires aggressive attributes is crucial to improving the diagnosis and treatment of patients. Herein, we demonstrated that nanometer-sized extracellular vesicles released by tumors promote cancer stemness and tumorigenesis. Within these oncogenic vesicles, we identified a key component that functions as a potent modulator of cancer aggressiveness. By inhibiting this functional component of EVs using a neutralizing antibody, tumor growth was profoundly attenuated in mice. This hints at a potentially effective therapeutic alternative for patients with cancer.
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•Elevated pIgR levels are found in circulating extracellular vesicles from patients with liver cancer.•EV-pIgR promotes cancer stemness and cancerous phenotypes in recipient liver cancer cells.•EV-pIgR promotes liver cancer cell aggressiveness by activating the PDK1/Akt/GSK3β/β-catenin signaling axis.•Combined treatment using sorafenib and anti-pIgR antibody attenuates growth of patient-derived xenografts in mice.
The complement system is involved in the immunosurveillance of pathogens and tumour cells. Proteomic profiling revealed that extracellular vesicles (EVs) released by metastatic hepatocellular ...carcinoma (HCC) cells contained a significant number of complement proteins. Complement Factor H (CFH), an abundant soluble serum protein that inhibits the alternative complement pathway, was found to be highly expressed in EVs of metastatic HCC cell lines. Here, we investigated the functional role of EV‐CFH and explored the therapeutic efficacy of targeting EV‐CFH with an anti‐CFH antibody in HCC. The results showed that EVs that are enriched in CFH promoted HCC cell growth, migration, invasiveness and enhanced liver tumour formation in mice. EV‐CFH also promoted metastasis, which was significantly abrogated when treated with an anti‐CFH antibody. These findings demonstrate an unexplored function of EV‐CFH in protecting HCC cells by evading complement attack, thereby facilitating tumorigenesis and metastasis. Lastly, we demonstrated the therapeutic efficacy of an anti‐CFH antibody in suppressing tumour formation in a syngeneic mouse model. This study suggests a new therapeutic strategy for HCC, by inhibiting EV‐CFH with a tumour specific anti‐CFH antibody.
Background
Extracellular vesicles (EVs) play pivotal roles in tumor growth, cancer metastasis and angiogenesis. Here, we aimed to identify proteins that contribute to the functionality of EVs derived ...from metastatic hepatocellular carcinoma (HCC) cells.
Methods
Proteins of EVs derived from metastatic HCC cells and normal liver cells were analyzed by mass spectrometry. Proteomic profiling identified actin-related protein 2/3 complex subunit 2 (ARPC2) to be highly expressed in EVs of metastatic HCC cells. The expression of ARPC2 in EVs and HCC tissues was examined using immunoblotting and TCGA database, respectively. The functional roles of EV-ARPC2 were investigated by knockout approach and various in vitro and in vivo assays.
Results
ARPC2 was highly expressed in EVs of metastatic cells but barely detected in non-metastatic HCC cells and normal liver cells. Immunogold labeling showed the presence of APRC2 on the surface of EVs. Analysis of TCGA database of liver cancer revealed ARPC2 overexpression was correlated with poor prognosis of patients. ARPC2 was knockout in metastatic HCC cells. EVs derived from knockout cells displayed compromised activity in enhancing cell growth, motility and metastasis compared to EVs of control cells. Pimozide, an inhibitor of APRC2, also inhibited the promoting effect of EVs of metastatic cells in lung colonization of tumor cells in mice.
Conclusion
This study reveals previously unreported expression and function of ARPC2 in EVs. EVs with highly expressed ARPC2 enhance cancer cell growth and metastasis. ARPC2 may provide a prospective target for the novel treatment of HCC patients.
Graphical abstract
Current screening programs and cancer therapies effectively reduce theincidence of colorectal cancer (CRC) and improve clinical outcome of the patients.However, CRC remains as the third most common ...cancer and the second leadingcause of cancer-related death worldwide. Herein, chemoprevention is anattractive complementary strategy to reduce CRC incidence and relatedmortalities. Yet, current chemopreventive agents are associated with severetoxicity which hinders their benefits. Therefore, it is imperative to devise novelchemopreventive agents to prevent this malignancy.Bufalin is a cardiac glycoside extracted from a traditional Chinese medicine Chansu. It has been previously characterized as a potent anti-cancer agent. Also,the use of cardiac glycoside was reported to be associated with reduced risk ofcancers and cancer recurrence in epidemiological studies. Notably, Huachansu,the clinical adaptation of Chansu, has been adopted for cancer treatment inhuman without significant sign of toxicity. These pieces of evidence highlightedbufalin as a potential candidate for CRC prevention.In this study, the role of bufalin in CRC chemoprevention was evaluated using twomouse colon carcinogenesis models, namely colitis-associated CRC model andApcmin/+ intestinal cancer model, which imitated the major risk factors for CRC inhuman. Mice were provided with bufalin throughout the studies and theprotective effect of bufalin against the development of CRC was examined.Bufalin treatment remarkably prevented colonic and intestinal carcinogenesis inboth models without noticeable adverse effect. For colitis-associated CRC model,bufalin-treated mice exhibited a significant reduction in the number, size andmultiplicity of colonic tumors. Loss of body weight, shortening of colon andenlargement of spleen associated with the model were also significantlyalleviated after bufalin treatment. For Apcmin/+ mice, number and multiplicity but not size of colonic tumors and intestinal polyps were reduced after bufalintreatment. In both models, bufalin was shown to suppress tumor proliferation (asevidenced by reduced bromodeoxyuridine incorporation, reduced levels of cyclinA, cyclin D1, cyclin E, cyclin-dependent kinase-2 and -4, and elevated p21 and p27expressions) and promote apoptosis (as indicated by increased DNAfragmentation, promoted caspase-3 and caspase-9 cleavage, elevated Bax andBak levels and diminished Bcl-2 and Bcl-xL expressions). Also, bufalin treatmentreduced expression of inflammatory mediators (including tumor necrosis factoralpha,interleukin-1 beta, interleukin-6, and chemokine (C-X-C motif) ligand-1, -2 and -5) as well as paracrine cyclooxygenase-2 expression and alleviatedinflammatory response through nuclear factor-kappa B inactivation in the colitisassociatedCRC model. These protective effects of bufalin were attributed to itsrole in abolishing phosphoinositide 3-kinase and Wnt signal transduction.Taken together, this is the first study repurposing the role of bufalin from an anticanceragent into a chemopreventive drug. These findings open up a new avenuefor exploiting bufalin as a competent chemopreventive agent to prevent CRC inindividuals with inflammatory bowel diseases and familial adenomatouspolyposis who are at increased risk of developing this disease.
Telomerase reverse transcriptase (TERT) promoter (pTERT) mutation has often been described as a late event in gliomagenesis and it has been suggested as a prognostic biomarker in gliomas other than ...1p19q codeleted tumors. However, the characteristics of isocitrate dehydrogenase (IDH) wild type (wt) (IDHwt), pTERTwt glioblastomas are not well known. We recruited 72 adult IDHwt, pTERTwt glioblastomas and performed methylation profiling, targeted sequencing, and fluorescence in situ hybridization (FISH) for TERT structural rearrangement and ALT (alternative lengthening of telomeres). There was no significant difference in overall survival (OS) between our cohort and a the Cancer Genome Atlas (TCGA) cohort of IDHwt, pTERT mutant (mut) glioblastomas, suggesting that pTERT mutation on its own is not a prognostic factor among IDHwt glioblastomas. Epigenetically, the tumors clustered into classic‐like (11%), mesenchymal‐like (32%), and LGm6‐glioblastoma (GBM) (57%), the latter far exceeding the corresponding proportion seen in the TCGA cohort of IDHwt, pTERTmut glioblastomas. LGm6‐GBM‐clustered tumors were enriched for platelet derived growth factor receptor alpha (PDGFRA) amplification or mutation (p = 0.008), and contained far fewer epidermal growth factor receptor (EGFR) amplification (p < 0.01), 10p loss (p = 0.001) and 10q loss (p < 0.001) compared with cases not clustered to this group. LGm6‐GBM cases predominantly showed ALT (p = 0.038). In the whole cohort, only 35% cases showed EGFR amplification and no case showed combined chromosome +7/−10. Since the cases were already pTERTwt, so the three molecular properties of EGFR amplification, +7/−10, and pTERT mutation may not cover all IDHwt glioblastomas. Instead, EGFR and PDGFRA amplifications covered 67% and together with their mutations covered 71% of cases of this cohort. Homozygous deletion of cyclin dependent kinase inhibitor 2A (CDKN2A)/B was associated with a worse OS (p = 0.031) and was an independent prognosticator in multivariate analysis (p = 0.032). In conclusion, adult IDHwt, pTERTwt glioblastomas show epigenetic clustering different from IDHwt, pTERTmut glioblastomas, and IDHwt glioblastomas which are pTERTwt may however not show EGFR amplification or +7/−10 in a significant proportion of cases. CDKN2A/B deletion is a poor prognostic biomarker in this group.
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