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Contents

1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4142 Immunogenic Apoptosis Mediated by ER Stress. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415

2.1 Immunogenic Apoptosis: An Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4152.2 ROS-Based ER Stress: The Molecular Heart of Immunogenic Apoptosis? . . . . . . . . 4182.3 Danger Signaling Pathways and ROS-Based ER Stress. . . . . . . . . . . . . . . . . . . . . . . 420

3 Targeting ER-Stress-Induced Inflammation and Immunity in Cancer. . . . . . . . . . . . . . . . . 421References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 424

Abstract

ER stress-induced inflammation is a complex phenomenon which can have ei-ther disease-supporting or disease-controlling effects depending on the pathol-ogy of the particular disease in focus. In case of cancer, it has been observed that ER stress-induced inflammation can have both pro-tumorigenic as well as anti-

Contribution of ER Stress to Immunogenic Cancer Cell Death

Abhishek D. Garg, Dmitri V. Krysko, Jakub Golab, Peter Vandenabeele and Patrizia Agostinis

P. Agostinis, A. Samali (eds.), Endoplasmic Reticulum Stress in Health and Disease, DOI 10.1007/978-94-007-4351-9_18, © Springer Science+Business Media Dordrecht 2012

P. Agostinis () · A. D. GargDepartment of Cellular and Molecular Medicine, Cell Death Research & Therapy Unit, Catholic University of Leuven, Leuven, Belgiume-mail: [email protected]

D. V. Krysko · P. VandenabeeleDepartment for Molecular Biomedical Research, Molecular Signaling and Cell Death Unit, VIB, Ghent, Belgium

D. V. Krysko · P. VandenabeeleDepartment of Biomedical Molecular Biology, Ghent University, Ghent, Belgium

J. GolabDepartment of Immunology, Centre of Biostructure Research, Medical University of Warsaw, Warsaw Poland

J. GolabDepartment 3, Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland

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tumorigenic roles. Thus, therapeutic strategies that can tilt the balance towards anti-tumorigenic role might be our best bet. It has been suggested that thera-peutically induced reactive oxygen species (ROS)-based ER stress could insti-gate within the cancer cells, danger signaling pathways that lead to ‘emission’ of certain damage-associated molecular patterns (DAMPs). These molecules could ultimately cause ‘immunogenic apoptosis,’ a cell death modality that can revive anti-tumor immunity. These new findings point to the importance of therapeuti-cally targeting ER stress-induced inflammation in cancer. In the current chapter we discuss the prospects of inducing ER stress-induced inflammation that sup-ports anti-tumor immunity.

Keywords

Immunogenic apoptosis · Cell death · Cancer · Immunogenicity · Immune cells · Dendritic cells · ER stress · Tumors · Inflammation · Reactive oxygen species · Danger signals · Calreticulin · ATP · Immunotherapy · PDT

Abbreviations

APC Antigen presenting cellsCOX CyclooxygenaseCRT CalreticulinDAMP Damage-associated molecular patternsDC Dendritic cellsEcto- Surface exposedER Endoplasmic reticulumHMGB High mobility group boxHSP Heat shock proteinIL InterleukinPAMP Pathogen-associated molecular patternsPERK PKR-like ER kinaseROS Reactive oxygen speciesTLR Toll like receptorsTNF Tumor Necrosis FactorUPR Unfolded protein responseUVC Ultra-violet C

1 Introduction

ER stress-induced inflammation is a complex phenomenon as apparent from the discussions presented in Chap. 11 earlier. Depending upon the disease in consid-eration, ER stress-induced inflammation can have either disease-supporting or dis-ease-controlling effects. In case of pathologies like obesity and diabetes for instance,

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the disease-supporting or disease-augmenting role of ER stress-induced inflamma-tion is increasingly becoming apparent. However, this scenario is not as simple in case of cancer. ER stress-induced inflammation can have both pro-tumorigenic (discussed extensively in Chap. 11) as well as anti-tumorigenic roles, balancing each other in a tumor micro-environment. Thus, therapeutic strategies that can tilt the balance towards anti-tumorigenic role of ER stress-induced inflammation might be our best bet in the coming future. Therapeutic induction of immunogenic cancer cell death is one such emerging strategy. In following section, we have discussed the emergence and promises of immunogenic cancer cell death.

2 Immunogenic Apoptosis Mediated by ER Stress

The ‘cancer immunoediting’ theory (Fig. 1) contemplates that the immune system usually prevents progression of tumorigenic lesions in the initial stages, but full-blown tumors can still form because they can escape from the anti-tumorigenic immune response [1–3]. It has been proposed that the immune system participates in shaping the immunogenicity of tumor cells (Fig. 1) and leads to their clonal se-lection [1, 3]. During this process, the balance might tilt in favor of tumor-growth if the evolving lesions are not sufficiently immunogenic (Fig. 1). These less immu-nogenic cancer cells can ‘hide’ their antigenicity by different means: downregula-tion of antigen presentation, appearance of antigen loss variants, and induction of immunosuppression within the tumor microenvironment [1, 3]. Thus, it has been proposed that one way of overcoming this evolution is by increasing the immuno-genicity of cancer cells [3], probably by induction of immunogenic apoptosis. In the following section, we will discuss this concept in detail.

2.1 Immunogenic Apoptosis: An Overview

Research during recent years has shown that certain treatment modalities (dis-cussed later) not only eliminate cancer cells, predominantly by apoptosis, but also increase their immunogenicity (Fig. 2) [2]. These findings indicate the possibility of countering tumor-induced immunosuppression. This form of cell death has been termed immunogenic apoptosis. What makes immunogenic apoptosis an attractive therapeutic option is that it combines apoptosis in cancer cells with their ability to trigger anti-tumor immunity (Fig. 2) [4–7]. It has been observed that various bio-molecules, collectively named damage-associated molecular patterns (DAMPs), are responsible for mediating the immunogenicity of cells dying by immunogenic apoptosis [2, 8]. DAMPs (also called danger signals, alarmins or leaderless se-cretory proteins) are molecules that are intracellular under normal conditions but are immunostimulatory/pro-inflammatory when they are secreted or surface-ex-posed by the damaged or dying cells [2, 8, 9]. DAMPs are analogous to PAMPs (pathogen-associated molecular pattern), which are molecules defining pathogen


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immunogenicity [8]. The type, diversity and mode of emergence (exposure, secre-tion or release) of DAMPs are usually intricately associated with the biochemistry of a particular cell death pathway [6, 7, 10]. DAMPs can exert different effects that are vital for anti-tumor immunity, such as encouraging antigen processing and presentation and maturational processes in DCs, the major antigen-presenting cells (APCs) [2, 8].

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Fig. 1 An overview of ‘cancer immunoediting’ theory. Cancer immunoediting consists of three main phases i.e. elimination, equilibrium and escape. The elimination phase involves initial interactions between the host immune cells (first innate immune cells and then the cross-primed adaptive immune cells) and the ‘newly’ formed neoplastic/cancerous cells. During this phase the immune system is successful in exerting strong anti-tumor immune response. Most neoplastic lesions do not progress into full-blown tumors due to successful and complete execution of elimi-nation phase. However, in case of certain neoplastic lesions, tumor cell variants capable of surviv-ing the elimination phase are formed (due to gain in immuno-modulatory functions leading to low immunogenicity and immuno-evasion). Such cells enter the equilibrium phase. In the equilibrium phase, the immune system exerts selection pressure on the tumor cell population such that the ‘immunogenic’ cancer cells still susceptible to anti-tumor immune response are pushed towards ‘extinction’ thereby allowing ‘clonal expansion’ (or selection) of ‘low immunogenic’ and resis-tant tumor cell variants. Eventually when all the cancer cells that were susceptible to anti-tumor immune response have been eradicated, the equilibrium phase gives way to the escape phase. As the name suggests, the escape phase involves the immuno-evasive tumor cell variants that have escaped the anti-tumor immune response and are now ‘free’ to create full-blown tumors which can be malignant

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Unlike classical (physiological) apoptosis, which is tolerogenic, immunogenic apoptosis tends to be pro-inflammatory [2, 11]. Immunogenic apoptosis has all the major hallmarks of physiological apoptosis, but it possesses two main properties absent in the latter: (1) the ability to expose/secrete vital ‘immunogenic signals’ or DAMPs, and (2) the ability to activate the host immune system (maturation of APCs presenting tumor-associated antigens, which then might prime the adaptive immune system against target cell antigens) [5, 7, 12]. Of these two properties, the ability to emit important DAMPs is considered the more important property of immunogenic apoptosis. DAMPs that are vital for immunogenic apoptosis include surface-exposed calreticulin (ecto-CRT; a vital ‘eat me’ signal) [5, 12], surface-exposed HSP90 (ecto-HSP90; an ‘eat me’ signal) [13], secreted ATP (a ‘find me’ signal and inflammasome activator) [14, 15], released HMGB1 (vital for proper


Fig. 2 An overview of immunogenic cell death concept. Most chemotherapeutic or anti-cancer therapies are applied with the sole aim of debulking the tumor via tumor cell killing irrespec-tive of the cell death routine induced or the effect of these modalities on anti-tumor immune response. However, recently some specific therapeutic agents/modalities (discussed in the text) have emerged which induce immunogenic cell death (more specifically immunogenic apoptosis) in cancer cells via reactive oxygen species ( ROS)-based ER stress. The main consequence of this specific cell death routine is that—while leading to overall tumor cell killing (the original func-tion of anti-cancer therapeutics), this routine helps in efficient ‘revival’ of anti-tumor immune response. The main properties of immunogenic apoptosis (that differentiates this cell death routine from its immunosuppressive counterpart i.e. physiological apoptosis) are—(1) induction of anti-cancer vaccine effect, in vivo, (2) release and surface exposure of damage-associated molecular patterns (DAMPs) and (3) activation of the innate immune cells e.g. dendritic cells which undergo maturation characterized by respiratory burst, secretion of pro-inflammatory cytokines and surface up-regulation of maturation markers like CD80, CD83, CD86 and HLA-DR

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antigen presentation) [4, 7], and secreted/released heat shock proteins such as HSP70, CRT and HSP90 (capable of causing DC maturation, vital for proper an-tigen processing and important tumor antigen carriers) [16–22]. More information on DAMPs and their association with immunogenic apoptosis is available in other reviews [2, 4, 6, 7, 10, 23].

Immunogenic apoptosis tends to be stressor-dependent in that only selected agents or therapeutic modalities have been shown to induce it (Fig. 2). These in-clude anthracyclines such as mitoxantrone and doxorubicin [5, 12, 24], as well as oxaliplatin [25], UVC irradiation, γ-irradiation [5, 12], bortezomib [13], cyclophos-phamide [26], combined treatment with cisplatin + thapsigargin [27], combined treatment with heat shock + UVC irradiation + γ-irradiation [28] and “photo-ox-idative ER stress” (phox-ER stress) generated by hypericin-based photodynamic therapy (Hyp-PDT) (Garg et al. [29, 30]) [31]. It is intriguing that most of these immunogenic apoptosis-inducing agents can induce ER stress often accompanied by a ‘ROS component’ (especially in the case of anthracyclines and phox-ER stress) [12]. In various cases, it was shown that the presence of ER stress was crucial for surface exposure of immunogenic DAMPs such as ecto-CRT [5, 12]. The following sections provide a detailed discussion of the nature of this ‘ROS-based ER stress’ and the danger signaling pathways involved.

2.2 ROS-Based ER Stress: The Molecular Heart of Immunogenic Apoptosis?

Eight individual and two combination chemotherapeutic strategies (discussed in the previous section) are known to induce immunogenic apoptosis in cancer cells. Most of these treatments can induce ER stress either as a primary or a secondary effect accompanied by ROS production [2, 12]. The first screening for agents that can induce immunogenic apoptosis was restricted to 20 distinct apoptosis inducers [5]. Of these, the following were found not to induce immunogenic apoptosis: ‘classi-cal’ ER stress inducing agents (MG132, thapsigargin, tunicamycin and brefeldin), DNA-targeting agents (etoposide, camptothecin, mitomycin C and Hoechst 33342) and mitochondria-targeting agents (C2 ceramide, betulinic acid and arsenite) [5]. However, certain other agents, such as mitoxantrone, doxorubicin and idarubicin (anthracyclines) are immunogenic apoptosis inducers [5]. Later, other agents (UVC irradiation, γ-irradiation and oxaliplatin) were added to this list [12, 25]. Further analysis showed that these immunogenic apoptosis inducers can induce ER stress accompanied by ROS production, such that their effects (like ecto-CRT exposure and apoptosis induction) were diminished in the presence of anti-oxidants like glu-tathione ethyl ester and N-acetyl cysteine [12]. These observations established that ER stress accompanied by ROS production is essential for immunogenic apoptosis [12, 25]. It was recently shown that cisplatin (a platinum-based agent), which re-portedly can induce changes in redox metabolism [27], cannot induce immunogenic apoptosis because it cannot induce ER stress. However, when thapsigargin or tunic-

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amycin (classical ER stressors) was combined with cisplatin, the induced apoptosis was immunogenic [27]. These observations further emphasized the importance of ER stress comprising a ROS component in immunogenic apoptosis.

Although the exact nature of this ROS-based ER stress has not been fully char-acterized yet, the literature on anthracyclines gives some clues to its characteristics. Research has shown that anthracyclines carry out their primary therapeutic action ( i.e. DNA-intercalation based apoptosis) in three steps. First, they enter cancer cells by simple diffusion and bind with high affinity to the 20S proteasomal subunit of the 26S proteasome in the cytoplasm. Next, the complex of anthracycline and prote-asome translocate into the nucleus. Finally, since anthracyclines have higher affin-ity for DNA, they dissociate from the proteasomes and bind to DNA [30]. Thus, an-thracyclines can induce ER stress by acting as reversible non-competitive inhibitors of the chymotrypsin-like protease activity of the 26S proteasome [30, 31], much like bortezomib (discussed later) [32]. However, whether anthracycline-induced ER stress can be attributed to its proteasome inhibitory capabilities has not been explicitly demonstrated. On the other hand, anthracyclines can undergo redox reac-tions that sometimes result in formation of aglycones associated with the biological membranes and thereby form ROS near them [30]. This applies to all the biological membranes and not to a particular sub-cellular organelle [30]. Thus, anthracycline-induced ROS-based ER stress is neither a primary effect nor specifically directed towards the ER. Moreover, further research is required to understand in detail the nature of this effect.

On the other hand, if ROS production is directed predominantly towards the ER (on target effect) via induction of phox-ER stress, it might cause a more ‘robust’ immunogenic apoptosis (Garg et al. [29, 30]) accompanied by enhanced pre-apop-totic surface exposure/release of crucial DAMPs like ecto-CRT and secreted ATP [10, 29, 33]. Phox-ER stress can be induced by what is known as hypericin-based Photodynamic Therapy or Hyp-PDT [34, 35]. PDT can induce oxidative stress at certain particular sub-cellular sites by activating organelle-associated photosensitiz-ers (PTS) [35, 36]. Once excited by light of appropriate wavelength, PTS can gen-erate organelle-localized ROS, which can cause considerable damage to the cells and possibly kill them [35, 36]. Hyp-PDT utilizes an ER-associated PTS called hypericin, which, when activated by visible light, causes ROS-based ER stress and mitochondrial (intrinsic) apoptosis [34, 35, 37].

Based on the discussion so far, ROS-based ER stress can be considered vital for induction of immunogenic apoptosis. But whether this stress (or a part of it) is indis-pensible is a question that requires further research because certain inducers of im-munogenic apoptosis mentioned above (bortezomib, γ-irradiation and cyclophos-phamide) have not yet been fully characterized in terms of inducing ROS-based ER stress. For instance, while γ-irradiation and cyclophosphamide are associated with immunogenic apoptosis [7, 12, 26] and can lead to generation of ROS [38, 39], their ER stress inducing capabilities are largely unexplored. Also, whether the ROS produced affect the ER remains unexplored. On the other hand, bortezomib, a 26S proteasome inhibitor, is a potent ER stressor [40] and inducer of immunogenic


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apoptosis [13]. However, whether this effect is ROS dependent has not been di-rectly investigated. It should be mentioned, however, that bortezomib can increase ROS production in treated cells [41], and so the presence of ROS-based ER stress behind its action remains a possibility.

2.3 Danger Signaling Pathways and ROS-Based ER Stress

ROS-based ER stress is important in induction of immunogenic apoptosis mainly because it helps in ‘emission’ of DAMPs that ultimately define the immunogenic-ity of the apoptotic cell [2, 7, 12]. ROS-based ER stress has been shown to activate ‘danger signaling’ pathways in cells treated with immunogenic apoptosis induc-ers ( e.g. anthracyclines, UVC, oxaliplatin). These pathways, which are activated mainly during the pre-apoptotic stage, help in exporting DAMPs to the extracellular space [4, 6, 7]. DAMPs such as CRT, HSP90, BiP and HSP70 reach the extracellular space, where they are mostly exposed on the outer leaflet of the plasma membrane, but a molecular pathway responsible for this transportation has been elucidated only for CRT [2]. Ecto-CRT is essential for the overall immunogenicity of a dying cell [5]. Agents like anthracyclines, oxaliplatin and UVC light induce ecto-CRT via the simultaneous action of two signaling modules around the ER: the ER stress module and the apoptotic module [2, 12]. The ER stress module involves activation of the PERK-eIF2α arm, whereas the apoptotic module involves caspase-8 based cleav-age of BAP31 (ER-sessile protein) and BAX/BAK [12]. Following the action of these two modules, CRT follows anterograde transport from the ER to the Golgi and SNARE-dependent exocytosis to reach the surface of cells treated with anthra-cycline or oxaliplatin [12]. However, this complex pathway might not be used for ecto-CRT mobilization by all the agents because the agents (like anthracyclines and oxaliplatin) that induce this pathway do not cause strong ROS production directed predominantly towards ER. In fact, if we induce primary, ‘on target’ ROS-based ER stress via phox-ER stress induced by Hyp-PDT, this ecto-CRT translocation pathway is considerably simplified, and phosphorylation of eIF2α and pre-apop-totic partial activation of caspase-8 are no longer required (Garg et al. [29, 30]). However, ecto-CRT exposure induced by phox-ER stress still requires the action of PERK and BAX/BAK around the ER. Beyond the ER, CRT follows the ‘classical’ secretory pathway to reach the surface of phox-ER stressed cells (Garg et al. [29, 30]). Interestingly, active ATP secretion induced by phox-ER stress was also depen-dent on PERK (but not on BAX/BAK) around the ER, as well as on the secretory pathway (Garg et al. [29, 30]).

The danger signaling pathways behind exposure/secretion of DAMPs require further investigation. ER stress or UPR components such as PERK play a central role in the danger signaling pathways that have been studied [12]. To design ways to modulate the effects of ER stress, it is important to understand the role of ER stress in danger signaling more fully.

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3 Targeting ER-Stress-Induced Inflammation and Immunity in Cancer

Anti-inflammatory drugs such as COX2 inhibitors, aspirin, and dexamethasone and other anti-inflammatory steroids reduce tumor incidence, slow down its pro-gression, and reduce mortality, particularly in sporadic colon cancer and to some extent in breast and prostate cancer [3, 42–44]. COX2 inhibitors such as celecoxib have shown promise in tumor suppression, but this has been mostly with short-term administration [45]. A recent study showed that long-term treatment with celecoxib could in fact promote chronic inflammation and tumorigenicity [45]. On the other hand, the possibility of using non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin for cancer treatment is promising not only because they are nonspecific but also because their long-term administration has fewer side-effect, with the exception of high-risk individuals. However, though these non-specific or broad inflammation-targeting strategies could work for some cancer patients, for most patients we need other strategies, especially along the lines of ER stress-induced inflammation. ER-stress-induced pro-tumorigenic inflamma-tion (discussed in Chap. 11) can be targeted in several ways: (1) neutralization of the effects of cytokines and chemokines that promote or support tumors; (2) in-hibition of transcription factors responsible for formation of tumor-promoting cy-tokines; (3) selective inhibition of UPR components that support pro-tumorigenic inflammation while sparing components that assist in anti-tumorigenic immunity/cytokine production; and (4) promoting/discovering therapeutics that lead to ER stress that induces immunogenic apoptosis in an attempt to ‘revive’ anti-tumor immunity.

Undesirable cytokines can be neutralized by treatment with cytokine-specific soluble receptors, antibodies against cytokine receptors, or anti-cytokine antibodies [46]. Several such strategies against TNF-α, IL-6, IL-1, IL-23 and IL-17 have been approved or are in clinical trials [47]. Preclinical and clinical data have shown that these strategies against cancer are promising, but they have also shown that booster injections are required [46]. Thus, it has been proposed that these strategies be cou-pled with conventional anti-tumor treatments such as surgery or chemotherapy to achieve long-term effects [46, 47]. Nevertheless, some patients do not benefit from anti-cytokine therapy, and therefore development of other therapies is needed [47]. Alternatively, transcription factors such as NF-κB that are activated by ER stress and cause production of tumor-promoting cytokines (discussed in Chap. 11) can also be targeted directly. It has been observed that NF-κB inhibition in metastatic cancer cells can convert inflammation-promoted tumor growth (IFN-induced as well as TRAIL expression-dependent) into inflammation-induced tumor regression [48]. However, the problems of therapeutic targeting of NF-κB mentioned previ-ously in Chap. 11 also apply to cancer. Moreover, it was recently shown that long-term treatment with celecoxib, which inhibits NF-κB, actually increases chronic intestinal inflammation and promotes tumorigenicity in the mouse model of colon tumorigenesis [45].


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Therapeutic agent/modality

Therapeutic effect Immunological Effects References

Bortezomib A proteasome inhibitor that creates ER stress by inhibiting the ER-associ-ated degradation (ERAD) pathway and thereby causing accumulation of misfolded proteins within the ER

Can help in surface translocation of HSP90 and can inhibit NF-κB activity

[2, 13, 49]

Brefeldin A (BFA) An inhibitor of the ER-to-Golgi transport. It induces ER stress by causing accumulation in the ER of proteins that are normally trafficked to the Golgi complex

Its immunological effects have not been investigated thoroughly, but it has been shown to inhibit the ‘anti-cancer vaccine effect’

[2, 12, 52]

Curcumin Curcumin causes apopto-sis via engagement of the ER stress pathway

Can modulate the activa-tion of certain immune cells, e.g. macrophages, neutrophils, natural killer cells, DCs, B cells and T cells. At lower doses it has the ability to enhance the antibody responses, in vivo

[49, 55]

Celecoxib A COX-2 enzyme inhibi-tor that can cause cell death via ER stress

Can inhibit biosynthe-sis of prostaglandin E2 (PGE2), a potent immunosuppressant that assists in tumor angiogenesis and tumor-induced immune dysfunction

[49, 56]

Ritonavir Induces ER stress by interfering with the ERAD machinery

Can enhance antibody response, but the effects of this drug on tumor microenvironment have not been investigated explicitly

[49, 57]

HSP90 inhibitors Can cause ER stress via activation of all three UPR branches and thereby lead to death of cancer cells

Geldanamycin (an HSP90 inhibitor) has been shown to inhibit surface translocation of HSP90. Besides, there is some speculation that HSP90 inhibitors can be immunosuppressive

[2, 13, 49, 58]

Table 1 ER stress-targeting therapeutic modalities against cancer and their immunological effects

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Drugs targeting UPR-induced inflammation are rare, but several drugs that target one or more branches of the UPR pathway or overall ER stress in cancer are either being used clinically or are under development [49–51]. ER stress tar-geting drugs currently being evaluated for cancer treatment ( in vitro or in vivo, pre-clinical or clinical) were not developed with the mechanics of ER stress-induced inflammation in mind. This is hardly surprising, because the effects of ER-stress-induced inflammation in cancer have been receiving sufficient atten-tion only recently. However, in recent years, increasing knowledge of how these agents can modulate inflammation or immune responses have made it possible to examine their potential use for ER stress-induced inflammation or immunity in cancer. If we consider the dual role of ER-stress-induced inflammation (inducing pro or anti-tumor immunity), then some ER-stress-inducing agents that encourage anti-tumorigenic inflammation could be useful. These agents include curcumin, celecoxib, bortezomib, anthracyclines, oxaliplatin and photodynamic therapy. But others, e.g. brefeldin A or its analogs and HSP90 inhibitors, might not be so useful. The therapeutic and immunological effects of these ER-stress-targeting agents in cancer are shown in Table 1. This table shows that agents such as brefeldin A (or their analogues) could interfere with the cytokine profile of the microenvironment without discriminating between pro- and anti-tumorigenic factors [52]. The table also shows that these agents inhibit surface translocation of DAMPs that depend on the secretory pathway ( e.g. calreticulin), and reduce a dying cell’s immunoge-


Therapeutic agent/modality

Therapeutic effect Immunological Effects References

Photodynamic therapy (PDT)

Induces ER stress via excitation of ER-associ-ated photosensitizers/dye ( e.g. hypericin) that gen-erate ER-directed ROS

PDT is capable of activating a number of immunological pro-cesses like neutrophilia, acute-phase response, direct activation of immune cells, comple-ment cascade activation and activation of produc-tion of cytokines/che-mokines. PDT can also cause surface exposure/extracellular release of DAMPs

[50, 56]

Anthracyclines (Mito-xantrone/Doxorubicin) and Oxaliplatin

Induce ER stress accompanied by ROS production. Anthracy-clines might inhibit 26S proteasome activity

Anthracyclines and oxaliplatin have been found to be capable of exposing/secreting various DAMPs and inducing immunogenic apoptosis vital for anti-tumor immunity

[5, 12, 24]

Table 1 (continued)

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nicity [12]. Similarly, HSP90 inhibitors could abrogate the immunogenicity based on surface exposure of HSP90 [13].

The future of therapeutic targeting of ER-stress-induced inflammation in the tumor microenvironment lies in agents that can reduce or control pro-tumorigenic inflammation while promoting anti-tumorigenic immunity. Currently, two ap-proaches that come close to this idea are bortezomib and hypericin-based PDT (Hyp-PDT). Bortezomib, while inhibiting NF-κB-based inflammation, causes immunogenic cancer cell death accompanied or mediated by surface exposure of HSP90. Similarly, Hyp-PDT can also cause immunogenic cancer cell death (Garg et al. [29, 30]) accompanied by exposure or secretion of DAMPs [10, 29, 33]. Moreover, Hyp-PDT has been shown to delay or slow down NF-κB activation [53] in cancer cells, or even to inhibit or suppress it, in case of prior presence of acti-vated NF-κB [54]. Hyp-PDT has also been shown to inhibit or suppress the binding activity of AP-1 and the secretion of GM-CSF in treated cancer cells [54]. Further research is required to ascertain whether the ability of Hyp-PDT to suppress NF-κB and AP-1 activity coupled with its ability to cause immunogenic apoptosis can be exploited for clinical use. However, there is clearly a need for new therapeutic agents that can effectively target ER-stress-induced inflammation in the tumor mi-croenvironment.

Acknowledgments The work from the laboratory of P.A. was supported by a GOA grant (GOA/11/2010–2015). This also presents research results of the IAP6/18, funded by the Inter-university Attraction Poles Programme initiated by the Belgian State, Science Policy Office. This work was supported by the Fund for Scientific Research Flanders (FWO-Vlaanderen, G072810 N to P.A. and D.V.K.) and by an individual research grant from FWO-Vlaanderen (31507110 to D.V.K.). D.V.K. is a postdoctoral fellow paid by fellowship from FWO-Vlaanderen. Research in the Vandenabeele unit has been supported by Flanders Institute for Biotechnology (VIB), by European grants (FP6 ApopTrain, MRTN-CT-035624; FP7 EC RTD Integrated Project, Apo-Sys, FP7–200767; Euregional PACT II), and Flemish grants (Fonds Wetenschappelijke Onder-zoek Vlaanderen, 3G.0218.06), Ghent University grants (MRP, GROUP-ID). P.V. is holder of a Methusalem grant (BOF09/01M00709) from the Flemish Government. The research in the lab of J.G. is supported by European Regional Development Fund through Innovative Economy grant POIG.01.01.02–00-008/08. J.G. is a member of TEAM Programme co-financed by the Foundation for Polish Science and the EU European Regional Development Fund. J.G. is a recipient of the Mistrz Award from the Foundation for Polish Science. The figures in this chapter were produced using Servier Medical Art (www.servier.com), for which the authors would like to acknowledge Servier. We thank Dr. Amin Bredan (DMBR-VIB, Ghent) for editing the manuscript.

References

1. Dunn GP, Bruce AT, Ikeda H, Old LJ, Schreiber RD (2002) Cancer immunoediting: from immunosurveillance to tumor escape. Nat Immunol 3(11):991–998. doi:10.1038/ni1102-991 (ni1102-991 [pii])

2. Garg AD, Nowis D, Golab J, Vandenabeele P, Krysko DV, Agostinis P (2010) Immunogenic cell death, DAMPs and anticancer therapeutics: an emerging amalgamation. Biochim Bio-phys Acta 1805(1):53–71. doi:S0304-419X(09)00056-0 [pii] (10.1016/j.bbcan.2009.08.003)

A. D. Garg et al.

425

3. Grivennikov SI, Greten FR, Karin M (2010) Immunity, inflammation, and cancer. Cell 140(6):883–899. doi:S0092-8674(10)00060-7 [pii] (10.1016/j.cell.2010.01.025)

4. Green DR, Ferguson T, Zitvogel L, Kroemer G (2009) Immunogenic and tolerogenic cell death. Nat Rev Immunol 9(5):353–363. doi:nri2545 [pii] (10.1038/nri2545)

5. Obeid M, Tesniere A, Ghiringhelli F, Fimia GM, Apetoh L, Perfettini JL, Castedo M, Mignot G, Panaretakis T, Casares N, Metivier D, Larochette N, van Endert P, Ciccosanti F, Piacentini M, Zitvogel L, Kroemer G (2007) Calreticulin exposure dictates the immunogenicity of can-cer cell death. Nat Med 13(1):54–61. doi:nm1523 [pii] (10.1038/nm1523)

6. Zitvogel L, Kepp O, Kroemer G (2010) Decoding cell death signals in inflammation and im-munity. Cell 140(6):798–804. doi:S0092-8674(10)00167-4 [pii] (10.1016/j.cell.2010.02.015)

7. Zitvogel L, Kepp O, Senovilla L, Menger L, Chaput N, Kroemer G (2010) Immunogenic tumor cell death for optimal anticancer therapy: the calreticulin exposure pathway. Clin Can-cer Res 16(12):3100–3104. doi:1078-0432.CCR-09-2891 [pii] (10.1158/1078-0432.CCR-09-2891)

8. Bianchi ME (2007) DAMPs, PAMPs and alarmins: all we need to know about danger. J Leu-koc Biol 81(1):1–5. doi:jlb.0306164 [pii] (10.1189/jlb.0306164)

9. Verfaillie T, Garg AD, Agostinis P (2010) Targeting ER stress induced apoptosis and inflam-mation in cancer. Cancer Lett. doi:10.1016/j.canlet.2010.07.016. doi:S0304-3835(10)00364-2 [pii] (10.1016/j.canlet.2010.07.016)

10. Garg AD, Krysko DV, Vandenabeele P, Agostinis P (2011) DAMPs and PDT-mediated photo-oxidative stress: exploring the unknown. Photochem Photobiol Sci 10(5):670–680. doi:10.1039/c0pp00294a

11. Kepp O, Tesniere A, Zitvogel L, Kroemer G (2009) The immunogenicity of tumor cell death. Curr Opin Oncol 21(1):71–76. doi:10.1097/CCO.0b013e32831bc375 (00001622-200901000-00013 [pii])

12. Panaretakis T, Kepp O, Brockmeier U, Tesniere A, Bjorklund AC, Chapman DC, Durchschlag M, Joza N, Pierron G, van Endert P, Yuan J, Zitvogel L, Madeo F, Williams DB, Kroemer G (2009) Mechanisms of pre-apoptotic calreticulin exposure in immunogenic cell death. EMBO J 28(5):578–590. doi:emboj20091 [pii] (10.1038/emboj.2009.1)

13. Spisek R, Charalambous A, Mazumder A, Vesole DH, Jagannath S, Dhodapkar MV (2007) Bortezomib enhances dendritic cell (DC)-mediated induction of immunity to human my-eloma via exposure of cell surface heat shock protein 90 on dying tumor cells: therapeu-tic implications. Blood 109(11):4839–4845. doi:blood-2006-10-054221 [pii] (10.1182/blood-2006-10-054221)

14. Ghiringhelli F, Apetoh L, Tesniere A, Aymeric L, Ma Y, Ortiz C, Vermaelen K, Panaretakis T, Mignot G, Ullrich E, Perfettini JL, Schlemmer F, Tasdemir E, Uhl M, Genin P, Civas A, Ryffel B, Kanellopoulos J, Tschopp J, Andre F, Lidereau R, McLaughlin NM, Haynes NM, Smyth MJ, Kroemer G, Zitvogel L (2009) Activation of the NLRP3 inflammasome in dendritic cells induces IL-1beta-dependent adaptive immunity against tumors. Nat Med 15(10):1170–1178. doi:nm.2028 [pii] (10.1038/nm.2028)

15. Martins I, Tesniere A, Kepp O, Michaud M, Schlemmer F, Senovilla L, Seror C, Metivier D, Perfettini JL, Zitvogel L, Kroemer G (2009) Chemotherapy induces ATP release from tumor cells. Cell Cycle 8(22):3723–3728. doi:10026 [pii]

16. Calderwood SK, Mambula SS, Gray PJ Jr (2007) Extracellular heat shock proteins in cell signaling and immunity. Ann N Y Acad Sci 1113:28–39. doi:annals.1391.019 [pii] (10.1196/annals.1391.019)

17. Lehner T, Wang Y, Whittall T, McGowan E, Kelly CG, Singh M (2004) Functional domains of HSP70 stimulate generation of cytokines and chemokines, maturation of dendritic cells and adjuvanticity. Biochem Soc Trans 32(Pt 4):629–632. doi:10.1042/BST0320629 (BST0320629 [pii])


426

18. Gastpar R, Gehrmann M, Bausero MA, Asea A, Gross C, Schroeder JA, Multhoff G (2005) Heat shock protein 70 surface-positive tumor exosomes stimulate migratory and cyto-lytic activity of natural killer cells. Cancer Res 65(12):5238–5247. doi:65/12/5238 [pii] (10.1158/0008-5472.CAN-04-3804)

19. Sidera K, Patsavoudi E (2008) Extracellular HSP90: conquering the cell surface. Cell Cycle 7(11):1564–1568. doi:6054 [pii]

20. Kuppner MC, Gastpar R, Gelwer S, Nossner E, Ochmann O, Scharner A, Issels RD (2001) The role of heat shock protein (hsp70) in dendritic cell maturation: hsp70 induces the matura-tion of immature dendritic cells but reduces DC differentiation from monocyte precursors. Eur J Immunol 31(5):1602–1609. doi:10.1002/1521-4141(200105)31:5 < 1602::AID-IM-MU1602 > 3.0.CO;2-W

21. Asea A, Kraeft SK, Kurt-Jones EA, Stevenson MA, Chen LB, Finberg RW, Koo GC, Calderwood SK (2000) HSP70 stimulates cytokine production through a CD14-dependant pathway, demonstrating its dual role as a chaperone and cytokine. Nat Med 6(4):435–442. doi:10.1038/74697

22. Bajor A, Tischer S, Figueiredo C, Wittmann M, Immenschuh S, Blasczyk R, Eiz-Vesper B (2011) Modulatory role of calreticulin as chaperokine for dendritic cell-based immunothera-py. Clin Exp Immunol. doi:10.1111/j.1365-2249.2011.04423.x

23. Krysko DV, Agostinis P, Krysko O, Garg AD, Bachert C, Lambrecht BN, Vandenabeele P (2011) Emerging role of damage-associated molecular patterns derived from mitochondria in inflammation. Trends Immunol 32(4):157–164. doi:10.1016/j.it.2011.01.005

24. Krysko DV, Kaczmarek A, Krysko O, Heyndrickx L, Woznicki J, Bogaert P, Cauwels A, Takahashi N, Magez S, Bachert C, Vandenabeele P (2011) TLR-2 and TLR-9 are sensors of apoptosis in a mouse model of doxorubicin-induced acute inflammation. Cell Death Differ. doi:10.1038/cdd.2011.4. doi:cdd20114 [pii] 10.1038/cdd.2011.4

25. Tesniere A, Schlemmer F, Boige V, Kepp O, Martins I, Ghiringhelli F, Aymeric L, Michaud M, Apetoh L, Barault L, Mendiboure J, Pignon JP, Jooste V, van Endert P, Ducreux M, Zit-vogel L, Piard F, Kroemer G (2010) Immunogenic death of colon cancer cells treated with oxaliplatin. Oncogene 29(4):482–491. doi:onc2009356 [pii] (10.1038/onc.2009.356)

26. Schiavoni G, Sistigu A, Valentini M, Mattei F, Sestili P, Spadaro F, Sanchez M, Lorenzi S, D’Urso MT, Belardelli F, Gabriele L, Proietti E, Bracci L (2011) Cyclophosphamide syner-gizes with type I interferons through systemic dendritic cell reactivation and induction of im-munogenic tumor apoptosis. Cancer Res 71(3):768–778. doi:0008-5472.CAN-10-2788 [pii] (10.1158/0008-5472.CAN-10-2788)

27. Martins I, Kepp O, Schlemmer F, Adjemian S, Tailler M, Shen S, Michaud M, Menger L, Gdoura A, Tajeddine N, Tesniere A, Zitvogel L, Kroemer G (2011) Restoration of the immu-nogenicity of cisplatin-induced cancer cell death by endoplasmic reticulum stress. Oncogene 30(10):1147–1158. doi:onc2010500 [pii] (10.1038/onc.2010.500)

28. Zappasodi R, Pupa SM, Ghedini GC, Bongarzone I, Magni M, Cabras AD, Colombo MP, Carlo-Stella C, Gianni AM, Di Nicola M (2010) Improved clinical outcome in indolent B-cell lymphoma patients vaccinated with autologous tumor cells experiencing immunogenic death. Cancer Res 70(22):9062–9072. doi:0008-5472.CAN-10-1825 [pii] (10.1158/0008-5472.CAN-10-1825)

29. Garg AD, Krysko DV, Verfaillie T, Kaczmarek A, Ferreira GB, Marysael T, Rubio N, Firczuk M, Mathieu C, Roebroek AJM, Annaert W, Golab J, de Witte P, Vandenabeele P and Agostinis P (2012) A novel pathway combining calreticulin exposure and ATP secretion in immuno-genic cancer cell death. EMBO J 31(5):1062–1079. doi:10.1038/emboj.2011.497

30. Garg AD, Krysko DV, Vandenabeele P, Agostinis P (2012) Hypericin-based photodynamic therapy induces surface exposure of damage-associated molecular patterns like HSP70 and calreticulin. Cancer Immunol Immunother 61(2):215–221. doi:10.1007/s00262-011-1184-2

A. D. Garg et al.

427

31. Declercq W, Agostinis P, Vandenabeele P (2011) 18th Euroconference on apoptosis in Ghent, Belgium, 1–4 September 2010. Cell Death Differ. doi:10.1038/cdd.2011.76. doi:cdd201176 [pii] (10.1038/cdd.2011.76)

32. Minotti G, Menna P, Salvatorelli E, Cairo G, Gianni L (2004) Anthracyclines: molecular ad-vances and pharmacologic developments in antitumor activity and cardiotoxicity. Pharmacol Rev 56(2):185–229. doi:10.1124/pr.56.2.6 (56/2/185 [pii])

33. Figueiredo-Pereira ME, Chen WE, Li J, Johdo O (1996) The antitumor drug aclacinomycin A, which inhibits the degradation of ubiquitinated proteins, shows selectivity for the chymotryp-sin-like activity of the bovine pituitary 20 S proteasome. J Biol Chem 271(28):16455–16459

34. Oerlemans R, Franke NE, Assaraf YG, Cloos J, van Zantwijk I, Berkers CR, Scheffer GL, Debipersad K, Vojtekova K, Lemos C, Van Der Heijden JW, Ylstra B, Peters GJ, Kaspers GL, Dijkmans BA, Scheper RJ, Jansen G (2008) Molecular basis of bortezomib resistance: protea-some subunit beta5 (PSMB5) gene mutation and overexpression of PSMB5 protein. Blood 112(6):2489–2499. doi:blood-2007-08-104950 [pii] (10.1182/blood-2007-08-104950)

35. Garg AD, Verfaillie T, Rubio N, Ferreira GB, Mathieu C, Agostinis P (2010) Hypericin-PDT treatment of cancer cells leads to surface exposure/extracellular release of DAMPs and acti-vates human immature dendritic cells (abstract). Belgian J Med Oncol 4(2):93–94

36. Buytaert E, Callewaert G, Hendrickx N, Scorrano L, Hartmann D, Missiaen L, Vandenheede JR, Heirman I, Grooten J, Agostinis P (2006) Role of endoplasmic reticulum depletion and multidomain proapoptotic BAX and BAK proteins in shaping cell death after hypericin-me-diated photodynamic therapy. FASEB J 20(6):756–758. doi:05-4305fje [pii] (10.1096/fj.05-4305fje)

37. Buytaert E, Dewaele M, Agostinis P (2007) Molecular effectors of multiple cell death path-ways initiated by photodynamic therapy. Biochim Biophys Acta 1776(1):86–107. doi:S0304-419X(07)00021-2 [pii] (10.1016/j.bbcan.2007.07.001)

38. Agostinis P, Berg K, Cengel KA, Foster TH, Girotti AW, Gollnick SO, Hahn SM, Hamblin MR, Juzeniene A, Kessel D, Korbelik M, Moan J, Mroz P, Nowis D, Piette J, Wilson BC, Golab J (2011) Photodynamic therapy of cancer: An update. CA Cancer J Clin. doi:10.3322/caac.20114. doi:caac.20114 [pii] (10.3322/caac.20114)

39. Buytaert E, Matroule JY, Durinck S, Close P, Kocanova S, Vandenheede JR, de Witte PA, Piette J, Agostinis P (2008) Molecular effectors and modulators of hypericin-mediated cell death in bladder cancer cells. Oncogene 27(13):1916–1929. doi:1210825 [pii] (10.1038/sj.onc.1210825)

40. Kim EM, Yang HS, Kang SW, Ho JN, Lee SB, Um HD (2008) Amplification of the gamma-irradiation-induced cell death pathway by reactive oxygen species in human U937 cells. Cell Signal 20(5):916–924. doi:S0898-6568(08)00009-0 [pii] (10.1016/j.cellsig.2008.01.002)

41. Korkmaz A, Topal T, Oter S (2007) Pathophysiological aspects of cyclophosphamide and ifosfamide induced hemorrhagic cystitis; implication of reactive oxygen and nitrogen species as well as PARP activation. Cell Biol Toxicol 23(5):303–312. doi:.1007/s10565-006-0078-0

42. Verfaillie T, Salazar M, Velasco G, Agostinis P (2010) Linking ER Stress to Autophagy: Potential Implications for Cancer Therapy. Int J Cell Biol. doi:10.1155/2010/930509. doi:10.1155/2010/930509

43. Ling YH, Liebes L, Zou Y, Perez-Soler R (2003) Reactive oxygen species generation and mitochondrial dysfunction in the apoptotic response to Bortezomib, a novel proteasome in-hibitor, in human H460 non-small cell lung cancer cells. J Biol Chem 278(36):33714–33723. doi:10.1074/jbc.M302559200 (M302559200 [pii])

44. Gupta RA, Dubois RN (2001) Colorectal cancer prevention and treatment by inhibition of cyclooxygenase-2. Nat Rev Cancer 1(1):11–21. doi:10.1038/35094017

45. Gierach GL, Lacey JV Jr., Schatzkin A, Leitzmann MF, Richesson D, Hollenbeck AR, Brin-ton LA (2008) Nonsteroidal anti-inflammatory drugs and breast cancer risk in the National


428

Institutes of Health-AARP Diet and Health Study. Breast Cancer Res 10(2):R38. doi:bcr2089 [pii] (10.1186/bcr2089)

46. Liu X, Plummer SJ, Nock NL, Casey G, Witte JS (2006) Nonsteroidal antiinflammatory drugs and decreased risk of advanced prostate cancer: modification by lymphotoxin alpha. Am J Epidemiol 164(10):984–989. doi:kwj294 [pii] (10.1093/aje/kwj294)

47. Carothers AM, Davids JS, Damas BC, Bertagnolli MM (2010) Persistent cyclooxygenase-2 inhibition downregulates NF-{kappa}B, resulting in chronic intestinal inflammation in the min/ + mouse model of colon tumorigenesis. Cancer Res 70(11):4433–4442. doi:0008-5472.CAN-09-4289 [pii] (10.1158/0008-5472.CAN-09-4289)

48. Zagury D, Gallo RC (2004) Anti-cytokine Ab immune therapy: present status and perspectives. Drug Discov Today 9(2):72–81. doi:10.1016/S1359-6446(03)02955-6 (S1359644603029556 [pii])

49. Kopf M, Bachmann MF, Marsland BJ (2010) Averting inflammation by targeting the cytokine environment. Nat Rev Drug Discov 9(9):703–718. doi:nrd2805 [pii] (10.1038/nrd2805)

50. Luo JL, Maeda S, Hsu LC, Yagita H, Karin M (2004) Inhibition of NF-kappaB in cancer cells converts inflammation- induced tumor growth mediated by TNFalpha to TRAIL-mediated tumor regression. Cancer Cell 6(3):297–305. doi:10.1016/j.ccr.2004.08.012 (S153561080400217X [pii])

51. Healy SJ, Gorman AM, Mousavi-Shafaei P, Gupta S, Samali A (2009) Targeting the endoplas-mic reticulum-stress response as an anticancer strategy. Eur J Pharmacol 625(1–3):234–246. doi:S0014-2999(09)00876-0 [pii] (10.1016/j.ejphar.2009.06.064)

52. Verfaillie T, Salazar M, Velasco G, Agostinis P (2010) Linking ER Stress to Autophagy: Po-tential Implications for Cancer Therapy. Int J Cell Biol 2010. doi:10.1155/2010/930509

53. Zhang K, Kaufman RJ (2008) From endoplasmic-reticulum stress to the inflammatory re-sponse. Nature 454(7203):455–462. doi:nature07203 [pii] (10.1038/nature07203)

54. Lore K, Andersson J (2004) Detection of cytokine- and chemokine-expressing cells at the single cell level. Methods Mol Biol 249:201–218. doi:1-59259-667-3-201 [pii]

55. Hendrickx N, Volanti C, Moens U, Seternes OM, de Witte P, Vandenheede JR, Piette J, Agostinis P (2003) Up-regulation of cyclooxygenase-2 and apoptosis resistance by p38 MAPK in hypericin-mediated photodynamic therapy of human cancer cells. J Biol Chem 278(52):52231–52239. doi:10.1074/jbc.M307591200 (M307591200 [pii])

56. Du HY, Olivo M, Mahendran R, Huang Q, Shen HM, Ong CN, Bay BH (2007) Hyperi-cin photoactivation triggers down-regulation of matrix metalloproteinase-9 expression in well-differentiated human nasopharyngeal cancer cells. Cell Mol Life Sci 64(7–8):979–988. doi:.1007/s00018-007-7030-1

57. Jagetia GC, Aggarwal BB (2007) “Spicing up” of the immune system by curcumin. J Clin Immunol 27(1):19–35. doi:.1007/s10875-006-9066-7

58. Garg AD, Nowis D, Golab J, Agostinis P (2010) Photodynamic therapy: illuminating the road from cell death towards anti-tumour immunity. Apoptosis 15(9):1050–1071. doi:.1007/s10495-010-0479-7

59. Michelet C, Chapplain JM, Petsaris O, Arvieux C, Ruffault A, Lotteau V, Andre P (1999) Dif-ferential effect of ritonavir and indinavir on immune response to hepatitis C virus in HIV-1 infected patients. AIDS 13(14):1995–1996

60. Neckers L (2002) Hsp90 inhibitors as novel cancer chemotherapeutic agents. Trends Mol Med 8(4 Suppl):S55–S61. doi:S147149140202316X [pii]

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Contribution of ER Stress to Immunogenic Cancer Cell Death

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