PMID- 38152992 OWN - NLM STAT- MEDLINE DCOM- 20240222 LR - 20240314 IS - 2523-3548 (Electronic) IS - 2523-3548 (Linking) VI - 44 IP - 2 DP - 2024 Feb TI - NHE7 upregulation potentiates the uptake of small extracellular vesicles by enhancing maturation of macropinosomes in hepatocellular carcinoma. PG - 251-272 LID - 10.1002/cac2.12515 [doi] AB - BACKGROUND: Small extracellular vesicles (sEVs) mediate intercellular communication that contributes to hepatocellular carcinoma (HCC) progression via multifaceted pathways. The success of cell entry determines the effect of sEV on recipient cells. Here, we aimed to delineate the mechanisms underlying the uptake of sEV in HCC. METHODS: Macropinocytosis was examined by the ability of cells to internalize dextran and sEV. Macropinocytosis was analyzed in Na(+)/H(+) exchanger 7 (NHE7)-knockdown and -overexpressing cells. The properties of cells were studied using functional assays. pH biosensor was used to evaluate the intracellular and endosomal pH. The expression of NHE7 in patients' liver tissues was examined by immunofluorescent staining. Inducible silencing of NHE7 in established tumors was performed to reveal the therapeutic potential of targeting NHE7. RESULTS: The data revealed that macropinocytosis controlled the internalization of sEVs and their oncogenic effect on recipient cells. It was found that metastatic HCC cells exhibited the highest efficiency of sEV uptake relative to normal liver cells and non-metastatic HCC cells. Attenuation of macropinocytic activity by 5-(N-ethyl-N-isopropyl)-amiloride (EIPA) limited the entry of sEVs and compromised cell aggressiveness. Mechanistically, we delineated that high level of NHE7, a sodium-hydrogen exchanger, alkalized intracellular pH and acidized endosomal pH, leading to the maturation of macropinosomes. Inducible inhibition of NHE7 in established tumors developed in mice delayed tumor development and suppressed lung metastasis. Clinically, NHE7 expression was upregulated and linked to dismal prognosis of HCC. CONCLUSIONS: This study advances the understanding that NHE7 enhances sEV uptake by macropinocytosis to promote the malignant properties of HCC cells. Inhibition of sEV uptake via macropinocytosis can be exploited as a treatment alone or in combination with conventional therapeutic approaches for HCC. CI - (c) 2023 The Authors. Cancer Communications published by John Wiley & Sons Australia, Ltd on behalf of SUN YAT-SEN UNIVERSITY CANCER CENTER. FAU - Yao, Yue AU - Yao Y AD - Department of Pathology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, P. R. China. AD - Department of Endocrinology and Metabolism, Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjing, P. R. China. FAU - Xu, Yi AU - Xu Y AD - Department of Pathology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, P. R. China. AD - Department of Hepatopancreatobiliary Surgery, Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjing, P. R. China. AD - State Key Laboratory of Oncology in South China, Cancer Center of Sun Yat-sen University, Guangzhou, Guangdong, P. R. China. FAU - Yu, Liang AU - Yu L AD - Department of Pathology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, P. R. China. AD - Department of Hepatopancreatobiliary Surgery, Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjing, P. R. China. FAU - Xue, Ting-Mao AU - Xue TM AD - Department of Pathology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, P. R. China. AD - Department of Hepatobiliary Surgery II, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, P. R. China. FAU - Xiao, Zhi-Jie AU - Xiao ZJ AD - Scientific Research Center, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, Guangdong, P. R. China. FAU - Tin, Pui-Chi AU - Tin PC AD - Department of Pathology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, P. R. China. FAU - Fung, Hiu-Ling AU - Fung HL AD - Department of Pathology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, P. R. China. FAU - Ma, Hoi-Tang AU - Ma HT AD - Department of Pathology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, P. R. China. AD - State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong, P. R. China. FAU - Yun, Jing-Ping AU - Yun JP AD - Department of Pathology, Cancer Center of Sun Yat-sen University, Guangzhou, Guangdong, P. R. China. FAU - Yam, Judy Wai Ping AU - Yam JWP AUID- ORCID: 0000-0002-5637-121X AD - Department of Pathology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, P. R. China. AD - State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong, P. R. China. LA - eng GR - LH2023H043/Natural Science Foundation of Heilongjiang Province/ GR - 202111159009/University Research Committee, University of Hong Kong/ GR - 17105322/Research Grants Council, University Grants Committee/ GR - XJ2020012/Society of Hong Kong Scholars/ GR - 2020-036/Society of Hong Kong Scholars/ GR - HMUMIF-22008/Harbin Medical Univeristy/ GR - HN2023-02/State Key Laboratory of Oncology in South China/ PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20231228 PL - United States TA - Cancer Commun (Lond) JT - Cancer communications (London, England) JID - 101723675 RN - 0 (Sodium-Hydrogen Exchangers) RN - 0 (SLC9A7 protein, human) SB - IM MH - Animals MH - Humans MH - Mice MH - *Carcinoma, Hepatocellular/genetics MH - Cell Line MH - *Liver Neoplasms/genetics MH - Sodium-Hydrogen Exchangers/genetics/metabolism MH - Up-Regulation PMC - PMC10876205 OTO - NOTNLM OT - hepatocellular carcinoma OT - macropinocytosis OT - pH regulation OT - small extracellular vesicles OT - sodium-hydrogen exchanger COIS- The authors declare no conflict of interest. EDAT- 2023/12/28 06:42 MHDA- 2024/02/21 11:22 PMCR- 2023/12/28 CRDT- 2023/12/28 05:35 PHST- 2023/12/13 00:00 [revised] PHST- 2023/03/06 00:00 [received] PHST- 2023/12/18 00:00 [accepted] PHST- 2024/02/21 11:22 [medline] PHST- 2023/12/28 06:42 [pubmed] PHST- 2023/12/28 05:35 [entrez] PHST- 2023/12/28 00:00 [pmc-release] AID - CAC212515 [pii] AID - 10.1002/cac2.12515 [doi] PST - ppublish SO - Cancer Commun (Lond). 2024 Feb;44(2):251-272. doi: 10.1002/cac2.12515. Epub 2023 Dec 28.