We previously found that lactic acidosis in the tumor environment was permissive to cancer cell surviving under glucose deprivation and demonstrated that neutralizing lactic acidosis restored cancer cell susceptibility to glucose deprivation. We then reported that alternate infusion of bicarbonate and anticancer agent into tumors via tumor feeding artery markedly enhanced the efficacy of transarterial chemoembolization (TACE) in the local control of hepatocellular carcinoma (HCC). Here we sought to further investigate the mechanism by which bicarbonate enhances the anticancer activity of TACE. We propose that interfering cellular pH by bicarbonate could induce a cascade of molecular events leading to cancer cell death. Alkalizing cellular pH by bicarbonate decreased pH gradient (ΔpH), membrane potential (ΔΨm), and proton motive force (Δp) across the inner membrane of mitochondria; disruption of oxidative phosphorylation (OXPHOS) due to collapsed Δp led to a significant increase in adenosine monophosphate (AMP), which activated the classical AMPK-mediated autophagy. Meanwhile, the autophagic flux was ultimately blocked by increased cellular pH, reduced OXPHOS, and inhibition of lysosomal proton pump in alkalized lysosome. Bicarbonate also induced persistent mitochondrial permeability (MPT) and damaged mitochondria. Collectively, this study reveals that interfering cellular pH may provide a valuable approach to treat cancer.
Your institute does not have access to this article
Subscribe to Journal
Get full journal access for 1 year
only $2.38 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Tax calculation will be finalised during checkout.
Get time limited or full article access on ReadCube.
All prices are NET prices.
All the data described in the manuscript are contained within the manuscript.
Sung H, Ferlay J, Siegel RL, Laversanne M, Soerjomataram I, Jemal A, et al. Global Cancer Statistics 2020: GLOBOCAN Estimates of Incidence and Mortality Worldwide for 36 Cancers in 185 Countries. CA Cancer J Clin. 2021;71:209–49.
Bruix J, Llovet JM. Prognostic prediction and treatment strategy in hepatocellular carcinoma. Hepatology. 2002;35:519–24.
Galle PR, Forner A, Llovet JM, Mazzaferro V, Piscaglia F, Raoul JL, et al. EASL Clinical Practice Guidelines: Management of hepatocellular carcinoma. J Hepatol. 2018;69:182–236.
Piscaglia F, Bolondi L. The intermediate hepatocellular carcinoma stage: Should treatment be expanded? Dig Liver Dis. 2010;42:S258–263.
Raoul JL, Sangro B, Forner A, Mazzaferro V, Piscaglia F, Bolondi L, et al. Evolving strategies for the management of intermediate-stage hepatocellular carcinoma: available evidence and expert opinion on the use of transarterial chemoembolization. Cancer Treat Rev. 2011;37:212–20.
Piscaglia F, Ogasawara S. Patient Selection for Transarterial Chemoembolization in Hepatocellular Carcinoma: Importance of Benefit/Risk Assessment. Liver Cancer. 2018;7:104–19.
Lencioni R, de Baere T, Soulen MC, Rilling WS, Geschwind JF. Lipiodol transarterial chemoembolization for hepatocellular carcinoma: A systematic review of efficacy and safety data. Hepatology. 2016;64:106–16.
Jansen MC, van Hillegersberg R, Chamuleau RAFM, van Delden OM, Gouma DJ, van Gulik TM. Outcome of regional and local ablative therapies for hepatocellular carcinoma: a collective review. Eur J Surg Oncol. 2005;31:331–47.
Llovet JM, Real MI, Montana X, Planas R, Coll S, Aponte J, et al. Arterial embolisation or chemoembolisation versus symptomatic treatment in patients with unresectable hepatocellular carcinoma: a randomised controlled trial. Lancet. 2002;359:1734–9.
Xie J, Wu H, Dai C, Pan Q, Ding Z, Hu D, et al. Beyond Warburg effect−dual metabolic nature of cancer cells. Sci Rep. 2014;4:4927.
Hu X, Chao M, Wu H. Central role of lactate and proton in cancer cell resistance to glucose deprivation and its clinical translation. Signal Transduct Target Ther. 2017;2:16047.
Wu H, Ding Z, Hu D, Sun F, Dai C, Xie J, et al. Central role of lactic acidosis in cancer cell resistance to glucose deprivation-induced cell death. J Pathol. 2012;227:189–99.
Chao M, Wu H, Jin K, Li B, Wu J, Zhang G, et al. A nonrandomized cohort and a randomized study of local control of large hepatocarcinoma by targeting intratumoral lactic acidosis. Elife. 2016;5:e15691.
Poburko D, Santo-Domingo J, Demaurex N. Dynamic regulation of the mitochondrial proton gradient during cytosolic calcium elevations. J Biol Chem. 2011;286:11672–84.
Oakhill JS, Steel R, Chen ZP, Scott JW, Ling N, Tam S, et al. AMPK is a direct adenylate charge-regulated protein kinase. Science. 2011;332:1433–5.
Hawley SA, Ford RJ, Smith BK, Gowans GJ, Mancini SJ, Pitt RD, et al. The Na+/Glucose Cotransporter Inhibitor Canagliflozin Activates AMPK by Inhibiting Mitochondrial Function and Increasing Cellular AMP Levels. Diabetes. 2016;65:2784–94.
Xiao B, Sanders MJ, Underwood E, Heath R, Mayer FV, Carmena D, et al. Structure of mammalian AMPK and its regulation by ADP. Nature. 2011;472:230–3.
Liu Y, Shi Y. Mitochondria as a target in cancer treatment. MedComm (2020). 2020;1:129–39.
Egan DF, Shackelford DB, Mihaylova MM, Gelino S, Kohnz RA, Mair W, et al. Phosphorylation of ULK1 (hATG1) by AMP-activated protein kinase connects energy sensing to mitophagy. Science. 2011;331:456–61.
Zois CE, Koukourakis MI. Radiation-induced autophagy in normal and cancer cells: towards novel cytoprotection and radio-sensitization policies? Autophagy. 2009;5:442–50.
Ju JS, Varadhachary AS, Miller SE, Weihl CC. Quantitation of “autophagic flux” in mature skeletal muscle. Autophagy. 2010;6:929–35.
Liu B, Fang M, Hu Y, Huang B, Li N, Chang C, et al. Hepatitis B virus X protein inhibits autophagic degradation by impairing lysosomal maturation. Autophagy. 2014;10:416–30.
Yue W, Hamaï A, Tonelli G, Bauvy C, Nicolas V, Tharinger H, et al. Inhibition of the autophagic flux by salinomycin in breast cancer stem-like/progenitor cells interferes with their maintenance. Autophagy. 2014;9:714–29.
Gowans GJ, Hawley SA, Ross FA, Hardie DG. AMP is a true physiological regulator of AMP-activated protein kinase by both allosteric activation and enhancing net phosphorylation. Cell Metab. 2013;18:556–66.
Ahmad F, Leake DS. Lysosomal oxidation of LDL alters lysosomal pH, induces senescence, and increases secretion of pro-inflammatory cytokines in human macrophages. J Lipid Res. 2019;60:98–110.
Caricato R, Giordano ME, Schettino T, Lionetto MG. Functional Involvement of Carbonic Anhydrase in the Lysosomal Response to Cadmium Exposure in Mytilus galloprovincialis Digestive Gland. Front Physiol. 2018;9:319.
Pasquier A, Vivot K, Erbs E, Spiegelhalter C, Zhang Z, Aubert V, et al. Lysosomal degradation of newly formed insulin granules contributes to β cell failure in diabetes. Nat Commun. 2019;10:3312.
Yoshii SR, Mizushima N. Monitoring and Measuring Autophagy. Int J Mol Sci. 2017;18:1865.
Kimura S, Noda T, Yoshimori T. Dissection of the autophagosome maturation process by a novel reporter protein, tandem fluorescent-tagged LC3. Autophagy. 2007;3:452–60.
Beyenbach KW, Wieczorek H. The V-type H+ ATPase: molecular structure and function, physiological roles and regulation. J Exp Biol. 2006;209:577–89.
Bartel K, Müller R, von Schwarzenberg K. Differential regulation of AMP-activated protein kinase in healthy and cancer cells explains why V-ATPase inhibition selectively kills cancer cells. J Biol Chem. 2019;294:17239–48.
Bernardi P, Vassanelli S, Veronese P, Colonna R, Szabó I, Zoratti M. Modulation of the mitochondrial permeability transition pore. Effect of protons and divalent cations. J Biol Chem. 1992;267:2934–9.
Malhi H, Gores GJ, Lemasters JJ. Apoptosis and necrosis in the liver: a tale of two deaths? Hepatology. 2006;43:S31–44.
Crompton M. The mitochondrial permeability transition pore and its role in cell death. Biochem J. 1999;341:233–49.
Tsujimoto Y, Shimizu S. Role of the mitochondrial membrane permeability transition in cell death. Apoptosis. 2007;12:835–40.
Nakagawa T, Shimizu S, Watanabe T, Yamaguchi O, Otsu K, Yamagata H, et al. Cyclophilin D-dependent mitochondrial permeability transition regulates some necrotic but not apoptotic cell death. Nature. 2005;434:652–8.
Baines CP, Kaiser RA, Purcell NH, Blair NS, Osinska H, Hambleton MA, et al. Loss of cyclophilin D reveals a critical role for mitochondrial permeability transition in cell death. Nature. 2005;434:658–62.
Rasola A, Sciacovelli M, Chiara F, Pantic B, Brusilow WS, Bernardi P. Activation of mitochondrial ERK protects cancer cells from death through inhibition of the permeability transition. Proc Natl Acad Sci. 2010;107:726–31.
Vaseva AV, Marchenko ND, Ji K, Tsirka SE, Holzmann S, Moll UM. p53 opens the mitochondrial permeability transition pore to trigger necrosis. Cell. 2012;149:1536–48.
Wu YT, Tan HL, Shui G, Bauvy C, Huang Q, Wenk MR, et al. Dual role of 3-methyladenine in modulation of autophagy via different temporal patterns of inhibition on class I and III phosphoinositide 3-kinase. J Biol Chem. 2010;285:10850–61.
Klionsky DJ, Abdalla FC, Abeliovich H, Abraham RT, Acevedo-Arozena A, Adeli K, et al. Guidelines for the use and interpretation of assays for monitoring autophagy. Autophagy. 2012;8:445–544.
Perera RM, Stoykova S, Nicolay BN, Ross KN, Fitamant J, Boukhali M, et al. Transcriptional control of autophagy-lysosome function drives pancreatic cancer metabolism. Nature. 2015;524:361–5.
Russo M, Russo GL. Autophagy inducers in cancer. Biochem Pharm. 2018;153:51–61.
Goodall ML, Fitzwalter BE, Zahedi S, Wu M, Rodriguez D, Mulcahy-Levy JM, et al. The Autophagy Machinery Controls Cell Death Switching between Apoptosis and Necroptosis. Dev Cell. 2016;37:337–49.
Liu J, Kuang F, Kroemer G, Klionsky DJ, Kang R, Tang D. Autophagy-Dependent Ferroptosis: Machinery and Regulation. Cell Chem Biol. 2020;27:420–35.
Shlomovitz I, Speir M, Gerlic M. Flipping the dogma - phosphatidylserine in non-apoptotic cell death. Cell Commun Signal. 2019;17:139.
Ibrahim-Hashim A, Cornnell HH, Abrahams D, Lloyd M, Bui M, Gillies RJ, et al. Systemic buffers inhibit carcinogenesis in TRAMP mice. J Urol. 2012;188:624–31.
Martin NK, Robey IF, Gaffney EA, Gillies RJ, Gatenby RA, Maini PK. Predicting the safety and efficacy of buffer therapy to raise tumour pHe: an integrative modelling study. Br J Cancer. 2012;106:1280–7.
Martin NK, Gaffney EA, Gatenby RA, Gillies RJ, Robey IF, Maini PK. A mathematical model of tumour and blood pHe regulation: The HCO3-/CO2 buffering system. Math Biosci. 2011;230:1–11.
Gong YN, Guy C, Olauson H, Becker JU, Yang M, Fitzgerald P, et al. ESCRT-III Acts Downstream of MLKL to Regulate Necroptotic Cell Death and Its Consequences. Cell. 2017;169:286–300.
Zargarian S, Shlomovitz I, Erlich Z, Hourizadeh A, Ofir-Birin Y, Croker BA, et al. Phosphatidylserine externalization, “necroptotic bodies” release, and phagocytosis during necroptosis. PLoS Biol. 2017;15:e2002711.
de Vasconcelos NM, Van Opdenbosch N, Van Gorp H, Parthoens E, Lamkanfi M. Single-cell analysis of pyroptosis dynamics reveals conserved GSDMD-mediated subcellular events that precede plasma membrane rupture. Cell Death Differ. 2019;26:146–61.
Klöditz K, Fadeel B. Three cell deaths and a funeral: macrophage clearance of cells undergoing distinct modes of cell death. Cell Death Disco. 2019;5:65.
Chen J, Kuroki S, Someda M, Yonehara S. Interferon-γ induces the cell surface exposure of phosphatidylserine by activating the protein MLKL in the absence of caspase-8 activity. J Biol Chem. 2019;294:11994–2006.
Jin C, Zhu X, Wu H, Wang Y, Hu X. Perturbation of phosphoglycerate kinase 1 (PGK1) only marginally affects glycolysis in cancer cells. J Biol Chem. 2020;295:6425–46.
Mauvezin C, Nagy P, Juhasz G, Neufeld TP. Autophagosome-lysosome fusion is independent of V-ATPase-mediated acidification. Nat Commun. 2015;6:7007.
Yang K, Lu Y, Xie F, Zou H, Fan X, Li B, et al. Cationic liposomes induce cell necrosis through lysosomal dysfunction and late-stage autophagic flux inhibition. Nanomed . 2016;11:3117–37.
Perry SW, Norman JP, Barbieri J, Brown EB, Gelbard HA. Mitochondrial membrane potential probes and the proton gradient: a practical usage guide. Biotechniques. 2011;50:98–115.
This work has been supported in part by China Natural Sciences Foundation projects (82073038, 81772947 to XH), a key project (2018C03009) funded by Zhejiang Provincial Department of Sciences and Technologies (to XH & MC), and the Fundamental Research Funds for the Central Universities (2017XZZX001-01, 2019FZJD009, to XH), National Ministry of Education, China. We thank Dr. Guo-Hua Fong (University of Connecticut School of Medicine, USA) for critical readings of our manuscript and constructive comments, Dr. Wei Liu (Zhejiang University) for the kind gift of plasmids GFP-LC3, Cherry-GFP-LC3, and Dr. Shanrong Cai for the statistical assistance (Zhejiang University).
The authors declare no competing interests.
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
About this article
Cite this article
Ying, C., Jin, C., Zeng, S. et al. Alkalization of cellular pH leads to cancer cell death by disrupting autophagy and mitochondrial function. Oncogene 41, 3886–3897 (2022). https://doi.org/10.1038/s41388-022-02396-6