Associate editor: B. Teicher
Subcellular targets of cisplatin cytotoxicity: An integrated view

https://doi.org/10.1016/j.pharmthera.2012.07.003Get rights and content

Abstract

Cisplatin is a chemotherapeutic drug widely used against a variety of cancers. Its clinical utility is severely limited by its toxicity, which mainly affects, but is not limited to, the inner ear and renal tubules. Cisplatin toxicity is determined by target tissue and cell accumulation, subcellular handling and trafficking through diverse subcellular structures, and interaction with macromolecules. Cisplatin accumulates and stresses different organelles from which delay signaling is activated, including mitochondria, lysosomes, the endoplasmic reticulum, the nucleus, the cell membrane and cytoskeleton, and can also be found in the cytosol. This article critically summarizes the available information in order to establish the connection among its known subcellular effects in a hierarchical and integrative framework. Cisplatin causes different types of cell death in a concentration-dependent manner. Knowledge of the events and signaling leading to the different phenotypes is also intertwined within the model, within the scope of the potential utility of this information in the improvement of the pharmacotoxicological profile of this drug. Perspectives for the key aspects that need to be addressed by future investigation are also outlined.

Introduction

Cisplatin (cis-diamminedichloroplatinum or CDDP) is a chemotherapeutic drug widely used against a wide variety of solid tumors (Cepeda et al., 2007). It was first described in 1845 by Michel Peyrone (thereafter Peyrone's salt); and its structure was elucidated in 1893 by Alfred Werner. Its antitumor potential was discovered in the 1960s after the observations from Barnett Rosenberg's group on its capacity to inhibit bacterial fission (Rosenberg et al., 1965) and the growth of sarcomas transplanted in mice. Initial clinical studies carried out by Hill's group (Hill et al., 1975) demonstrated its efficacy against several human malignancies, and it was first approved for clinical use in the USA in 1978 (Hill and Speer, 1982). Cisplatin is highly toxic for proliferating cells, because it forms adducts with DNA and impedes DNA replication and mitosis (Saris et al., 1996, Sorenson and Eastman, 1988). However, its therapeutic use and efficacy are limited by its side-effects, mostly nephrotoxicity (mainly tubular necrosis), ototoxicity (cochlear damage), neurotoxicity (mainly peripheral sensory neuropathy) and others. Side effects occur especially at high dosage by acting on several non-proliferating cell types (Barabas et al., 2008, Jaggi and Singh, 2012, Rybak et al., 2009, Sanchez-Gonzalez, Lopez-Hernandez, Lopez-Novoa and Morales, 2011). Intrinsic and acquired resistance is another limitation to the therapeutic effect of cisplatin on tumor cells (Cepeda et al., 2007). As such, cisplatin's cytotoxicity is at cross-roads of its therapeutic and side effects. Further knowledge of its cytotoxic mechanisms in tumor and normal cells might help improve the pharmaco-toxicological profile of this drug by exploiting potential differences in its handling or response.

The kidneys accumulate cisplatin. Also other organs such as the liver, prostate, spleen, bladder, muscle, testicle, pancreas, bowel, adrenal, heart, lung, cerebrum and cerebellum also accumulate the drug to a higher or lesser extent (Huo et al., 2005, Junior et al., 2007, McIntosh et al., 1997, Riviere et al., 1990, Wang et al., 2007). The pattern of tissue accumulation does not always coincide with the pattern of tissue toxicity (Staffhorst et al., 2008, Stewart et al., 1982). It might be possible that a given tissue accumulation of cisplatin results in a differential intracellular accumulation from tissue to tissue, or from cell type to cell type, with inverse accumulation within the tissue's extracellular compartment. This might explain why a higher accumulation in a determined organ would result in lower damage when compared to another organ with lower accumulation and higher damage. For example, Junior et al. (2007) have shown higher accumulation of cisplatin in the liver and spleen than in the kidneys. Also human tissue platinum concentrations were highest in liver and prostate (Stewart et al., 1982). However its main toxic effect is nephrotoxicity. Tumors also accumulate cisplatin. Yet, tumor accumulation, i.e. the tumor tissue-to-plasma partition coefficient, is lower than in many organs, even in many in which cisplatin has no significant or much milder effect (Junior et al., 2007, Staffhorst et al., 2008). As we have demonstrated (Sancho-Martinez et al., 2011), lower concentrations of cisplatin are needed to cause cell cycle arrest than to induce cell death. Because most somatic cells are not undergoing division (i.e. they rest in the G0 state) under normal circumstances, this might explain why subtoxic or low toxic doses of cisplatin exert an antitumor effect.

Intracellular determinants such as the red-ox status also condition cisplatin toxicity. This is because the molecule of cisplatin has much lower toxicity and reactivity than its aquated metabolites, which have much higher avidity for nucleophilic sites in macromolecules (Kartalou and Essigmann, 2001). Inside the cells, a low chloride environment, its chloride ions are substituted by water molecules (Andrews and Howell, 1990, Ekborn et al., 2003, Johnson et al., 1980). This process is modulated by the level of available molecules with free thiol groups, which capture cisplatin species and prevent them from binding other targets (Dabrowiak et al., 2002, Sadowitz et al., 2002).

Cisplatin causes cell death both by apoptosis and non-apoptotic, necrotic-like processes (Cepeda et al., 2007, Price et al., 2004, Ramirez-Camacho et al., 2008, Sato et al., 2001). The mode of cell death has been linked to cisplatin concentration. In tumor (Guchelaar et al., 1998, Sancho-Martinez et al., 2011) and non-tumor cells (Lieberthal et al., 1996, Sancho-Martinez et al., 2011), low concentrations of cisplatin induce apoptosis, whereas higher ones cause necrosis. Both apoptosis and necrosis have been also found in vivo, after treatment with this drug, in tumors and renal cells (Meyer and Madias, 1994, Sato et al., 2001). In the case of renal toxicity, necrosis is mostly found in the proximal tubule (along with apoptosis), whereas in the distal tubule only apoptosis is observed (Kroning et al., 2000, Megyesi et al., 1998, Price et al., 2004). This has been explained by a lower concentration of cisplatin reaching the distal tubule, as the bulk of filtered drug is reabsorbed in the proximal tubule (Kroning et al., 1999, Sancho-Martinez et al., 2011). Necrosis is a form of cell death that induces an inflammatory and innate immune response (Festjens et al., 2006, Nunez et al., 2010, Zong and Thompson, 2006). Necrotic cells contribute to activate the inflammatory response known to participate in the pathophysiological mechanisms of cisplatin's nephrotoxicity (Sanchez-Gonzalez, Lopez-Hernandez, Lopez-Novoa and Morales, 2011, Sanchez-Gonzalez, Lopez-Hernandez, Perez-Barriocanal, Morales and Lopez-Novoa, 2011). The consequences of tumoral necrosis in the context of the antitumoral effect of cisplatin are not well determined. All this means that, at least for a better control of cisplatin's side effects, both the injury sites and pathways leading to activation of apoptosis and those leading to necrosis need to be identified for appropriate and individual pharmacological targeting. The next sections of this review critically compile the information known on the effects of cisplatin at the subcellular level, which may lead to one form or another of cell death. They also intend to integrate this information in order to clarify the key effects of cisplatin compromising cell viability, and the intertwining and hierarchical organization of the responses; in order to put in perspective the main aspects that need further exploration for a better knowledge and improvement of its pharmaco-toxicological profile.

Section snippets

Transmembrane handling, intracellular trafficking and subcellular distribution

Classically, passive diffusion was considered the main mechanism of cellular uptake of cisplatin. This was based on the observation that, in general (i) accumulation is proportional to extracellular drug concentration, (ii) accumulation is not saturable, and (iii) structural analogs of cisplatin do not inhibit its accumulation (Gately and Howell, 1993). However, more recent observations challenge this concept. It was observed that, in different cell types, the whole uptake of cisplatin, or at

Mitochondrial effects

Exposure of cells to cisplatin causes characteristic mitochondrial alterations leading to the activation of the intrinsic pathway of apoptosis and other signals leading to cell death (reviewed in Cullen et al., 2007, Servais et al., 2008). When mitochondria are appropriately primed, the outer transmembrane potential is dissipated and the permeability of the outer membrane is increased. Mitochondrial permeabilization is under the control of proapoptotic members of the Bcl-2 family (Bax and Bak) (

Lysosomal toxicity

Lysosomal injury and alterations have been shown to cause cell death. Lysosomes are a source of cell death signaling, which results from lysosomal membrane permeabilization (LMP) and release of its content to the cytosol. Lysosomal fluid contains several proteases of the cathepsin family: cysteine protease cathepsins B, L and others, aspartic protease cathepsins D and E, and serine protease cathepsin G (Ivanova et al., 2008), most of which, especially cysteine cathepsins, are active at both

Endoplasmic reticulum stress

The endoplasmic reticulum (ER) plays a central role in cellular biosynthesis and intracellular calcium homeostasis (Gorlach et al., 2006, Paschen, 1996). Appropriate protein folding, maturing and specific post-translational modifications occur within the ER, from which proteins are driven to their cellular locations or secreted (Ellgaard et al., 1999). ER injury or alterations in ER functions may lead to accumulation of misfolded proteins or deregulation of calcium storage, causing a situation

Nuclear effects: genotoxic stress

Traditionally, DNA damage was considered the main mechanism of cisplatin cytotoxicity. Strikingly, only about 1% of the total amount of cisplatin accumulated in the cell is bound to the DNA (Yu et al., 2008). Cisplatin has been long recognized to localize to the nucleus, mainly in the nucleolus (bound to DNA and histone 3) and the inner side of the double nuclear membrane (Thompson et al., 1982). However, nuclear import and trans-membrane handling mechanisms are not well understood (Hall et

Effects involving the plasma membrane and cytoskeleton

Cisplatin also reacts with the plasma membrane (Hamel et al., 1990). It forms strong bonds with plasmalemmal proteins, and weaker but relevant interactions with negatively charged phospholipids (e.g. phosphatidylserine), in the form of coordination complexes (Jensen et al., 2010, Speelmans et al., 1997, Taylor et al., 1995). By reacting with proteins, cisplatin reduces the activity of some ion channels and transporters (Grunicke and Hofmann, 1992) including the Na/K ATPase, the sodium-proton

Cytosolic events

Cisplatin is found in the cytosol of exposed cells. From there it is believed to enter organelles and to accumulate in subcellular membranes. In addition, a central life-or-death decision mechanism lies with the cytoplasm, namely the ratio of pro-apoptotic to anti-apoptotic activity of the Bcl-2 family members, which is intimately implicated in cisplatin cytotoxicity (Breckenridge et al., 2003). Many apoptotic pathways initiated at different subcellular sites are funneled into this core

Overview and perspectives

Through its direct interaction with many cellular molecules including proteins, DNA and lipids, cisplatin affects diverse subcellular structures and organelles, disrupts many critical functions and, consequently, activates programmed signaling leading to cell death. As commented through the text, the influence of the local (subcellular) injury or signaling thereof in the overall deadly effect appears to vary from cell type to cell type, and even from study to study. Most of the signals

Acknowledgments

This work was supported by grants from Instituto de Salud Carlos III, Madrid, Spain [PI081900 and PI11/02278 to FJL-H]. JML-N's research group holds the Excellence mention from the Junta de Castilla y León [Group GR100] with associated funds.

References (387)

  • Q. Chen et al.

    Blockade of electron transport during ischemia preserves bcl-2 and inhibits opening of the mitochondrial permeability transition pore

    FEBS Lett

    (2011)
  • W. Chen et al.

    The lysosome-associated apoptosis-inducing protein containing the pleckstrin homology (PH) and FYVE domains (LAPF), representative of a novel family of PH and FYVE domain-containing proteins, induces caspase-independent apoptosis via the lysosomal–mitochondrial pathway

    J Biol Chem

    (2005)
  • G. Ciarimboli et al.

    Cisplatin nephrotoxicity is critically mediated via the human organic cation transporter 2

    Am J Pathol

    (2005)
  • T. Cirman et al.

    Selective disruption of lysosomes in HeLa cells triggers apoptosis mediated by cleavage of Bid by multiple papain-like lysosomal cathepsins

    J Biol Chem

    (2004)
  • F. Courjault-Gautier et al.

    Modulation of sodium-coupled uptake and membrane fluidity by cisplatin in renal proximal tubular cells in primary culture and brush-border membrane vesicles

    Kidney Int

    (1995)
  • J.B. Custodio et al.

    Cisplatin impairs rat liver mitochondrial functions by inducing changes on membrane ion permeability: prevention by thiol group protecting agents

    Toxicology

    (2009)
  • E. Cvitkovic

    Cumulative toxicities from cisplatin therapy and current cytoprotective measures

    Cancer Treat Rev

    (1998)
  • S. Denamur et al.

    Role of oxidative stress in lysosomal membrane permeabilization and apoptosis induced by gentamicin, an aminoglycoside antibiotic

    Free Radic Biol Med

    (2011)
  • H. Du et al.

    BH3 domains other than Bim and Bid can directly activate Bax/Bak

    J Biol Chem

    (2011)
  • P. Ducoroy et al.

    LF 15–0195 immunosuppressive agent enhances activation-induced T-cell death by facilitating caspase-8 and caspase-10 activation at the DISC level

    Blood

    (2003)
  • J.W. Eaton et al.

    Molecular bases of cellular iron toxicity

    Free Radic Biol Med

    (2002)
  • M. Enoksson et al.

    Caspase-2 permeabilizes the outer mitochondrial membrane and disrupts the binding of cytochrome c to anionic phospholipids

    J Biol Chem

    (2004)
  • E.L. Eskelinen

    Roles of LAMP-1 and LAMP-2 in lysosome biogenesis and autophagy

    Mol Aspects Med

    (2006)
  • E.L. Eskelinen et al.

    At the acidic edge: emerging functions for lysosomal membrane proteins

    Trends Cell Biol

    (2003)
  • R. Feng et al.

    Induction of ER stress protects gastric cancer cells against apoptosis induced by cisplatin and doxorubicin through activation of p38 MAPK

    Biochem Biophys Res Commun

    (2011)
  • N. Festjens et al.

    Necrosis, a well-orchestrated form of cell demise: signalling cascades, important mediators and concomitant immune response

    Biochim Biophys Acta

    (2006)
  • M. Forgac

    Structure and properties of the vacuolar (H+)-ATPases

    J Biol Chem

    (1999)
  • M. Fukuda

    Lysosomal membrane glycoproteins. Structure, biosynthesis, and intracellular trafficking

    J Biol Chem

    (1991)
  • C. Gajate et al.

    Lipid raft connection between extrinsic and intrinsic apoptotic pathways

    Biochem Biophys Res Commun

    (2009)
  • P. Golstein et al.

    Cell death by necrosis: towards a molecular definition

    Trends Biochem Sci

    (2007)
  • A. Gross et al.

    Caspase cleaved BID targets mitochondria and is required for cytochrome c release, while BCL-XL prevents this release but not tumor necrosis factor-R1/Fas death

    J Biol Chem

    (1999)
  • A. Ahmed-Ouameur et al.

    The effects of drug complexation on the stability and conformation of human serum albumin: protein unfolding

    Cell Biochem Biophys

    (2006)
  • J.D. Amaral et al.

    The role of p53 in apoptosis

    Discov Med

    (2007)
  • P.A. Andrews et al.

    Cellular pharmacology of cisplatin: perspectives on mechanisms of acquired resistance

    Cancer Cells

    (1990)
  • L.M. Antunes et al.

    Protective effects of vitamin C against cisplatin-induced nephrotoxicity and lipid peroxidation in adult rats: a dose-dependent study

    Pharmacol Res

    (2000)
  • I. Arany et al.

    Cisplatin-induced cell death is EGFR/src/ERK signaling dependent in mouse proximal tubule cells

    Am J Physiol Renal Physiol

    (2004)
  • D. Arnoult et al.

    Mitochondrial release of AIF and EndoG requires caspase activation downstream of Bax/Bak-mediated permeabilization

    EMBO J

    (2003)
  • D. Arnoult et al.

    Mitochondrial release of apoptosis-inducing factor occurs downstream of cytochrome c release in response to several proapoptotic stimuli

    J Cell Biol

    (2002)
  • A. Baez-Ruiz et al.

    Chronic inhibition of endoplasmic reticulum calcium-release channels and calcium-ATPase lengthens the period of hepatic clock gene Per1

    J Circadian Rhythms

    (2011)
  • K. Barabas et al.

    Cisplatin: a review of toxicities and therapeutic applications

    Vet Comp Oncol

    (2008)
  • S. Baritaki et al.

    Viral infection and cancer: the NF-kappaB/Snail/RKIP loop regulates target cell sensitivity to apoptosis by cytotoxic lymphocytes

    Crit Rev Immunol

    (2010)
  • M. Baritaud et al.

    Histone H2AX: the missing link in AIF-mediated caspase-independent programmed necrosis

    Cell Cycle

    (2010)
  • A. Basu et al.

    Cellular responses to cisplatin-induced DNA damage

    J Nucleic Acids

    (2010)
  • J.S.E. Bertinato et al.

    Ctr2 is partially localized to the plasma membrane and stimulates copper uptake in COS-7 cells

    Biochem J

    (2008)
  • J. Biagosch et al.

    Reduced expression of Bax in small cell lung cancer cells is not sufficient to induce cisplatin-resistance

    Eur J Med Res

    (2010)
  • J. Biermann et al.

    Characterization of regulatory mechanisms and states of human organic cation transporter 2

    Am J Physiol Cell Physiol

    (2006)
  • B.G. Blair et al.

    Copper transporter 2 regulates endocytosis and controls tumor growth and sensitivity to cisplatin in vivo

    Mol Pharmacol

    (2011)
  • B.G. Blair et al.

    Copper transporter 2 regulates the cellular accumulation and cytotoxicity of cisplatin and carboplatin

    Clin Cancer Res

    (2009)
  • D.G. Breckenridge et al.

    Regulation of apoptosis by endoplasmic reticulum pathways

    Oncogene

    (2003)
  • U.T. Brunk et al.

    Oxidative stress, growth factor starvation and Fas activation may all cause apoptosis through lysosomal leak

    Redox Rep

    (1999)
  • Cited by (144)

    View all citing articles on Scopus

    Conflict of interest statement: the authors declare that there are no conflicts of interest.

    View full text