Hallmarks of Cancer: Resistance to Cell Death(Types of cell death and apoptosis resistance mechanisms)

Prof. Dr. rer. nat. Anna Trauzold

Institut for Experimental Cancer Research

Aims of the lecture

After attending this lecture, students will be able to:

- define the terms apoptosis, necrosis, necroptosis, autophagy

- describe the mechanisms of apoptotic cell death (important points and terms:

caspases, intrinsic triggers, extrinsic triggers, type I/type II cells, death receptors,

dependence receptors)

- describe the role of death receptors in cancer (TRAIL receptors)

- name and define the potential apoptosis-resistance mechanisms operating in

tumor cells

- know and understand the mechanisms underlying anti-tumor and tumor-

promoting role of cell death

-apoptosis in anti-tumor therapie

Physiological cell death

• Elimination of infected/injured cells

• Elimination of tumor cells

• Embryogenesis

• Control of the tissue size

• Renewal of epithelia

• Selection (immune system)

(Patho)physiological cell death (too much)

• Cardiovascular diseases (cardiac infarction)

• Radio-/Chemotherapy

• Cirrhosis of the liver

• Neurodegenerative diseases (Morbus Parkinson)

• Infections (HIV, HBV, HCV)

(Patho)physiological cell death (too little)

Hanahan & Weinberg, 2011, Cell 144: 646-674

Efficient induction and successful execution of cell deathis an aim of many anti-tumor therapies

Until recently

Apoptosis vs. Necrosis

programmed vs. accidental

active vs. passive

Belizario et al., 2015, Mediators of Inflammation

DOI: 10.1155/2015/128076.

Programmed

(regulated)

cell deathApoptosis

activation

of caspases

silent death

without

inflammation

and

immune response

Active process Clarke & Smyth, 2007,

Nat. Biotech. 25: 192-3.

„eat me signal“

macrophage

Until recently

Accidental

cell deathNecrosis

cell death

with

inflammation

Passive processClarke & Smyth, 2007,

Nat. Biotech. 25: 192-3.

Until recently

induced by extremely harsh physical conditions

Apoptosis 213 116 256 616 357 271 385 895 180%

Necrosis 256 470 285 844 350 818 369 034 143.8%

Autophagic cell death 8661 14271 32435 38 665 446.4%

Anoikis 885 1156 1663 1801 203.5%

Cornification 759 814 915 939 124%

Mitotic catastrophe 506 654 932 994 196.4%

Necroptosis 106 318 1459 1909 1800,9%

Pyroptosis 82 203 789 1116 136.1%

Entosis 21 37 80 88 419%

Parthanatos 16 30 96 113 706%

Netosis 16 71 377 492 307.5%

Cell death modalities Number of articles in PubMed

Nov. 2011 Nov. 2013 Nov. 2017 Nov. 2018

Cell Death Differ. 2012 Jan;19(1):107-20.

No more valid equation!

Programmed

(regulated)

cell deathApoptosis

activation

of caspases

silent death

without

inflammation

and

immune response

• Existence of other forms of regulated cell death (necroptosis and autophagic cell death)

Programmed

(regulated)

cell deathApoptosis

activation

of caspases

silent death

without

inflammation

and

immune response

No more valid equation!

• Apoptosis can occur also without activation of caspases, caspases can also be activatedin other cell death modalities

• Existence of other forms of regulated cell death (necroptosis and autophagic cell death)

Programmed

(regulated)

cell deathApoptosis

activation

of caspases

silent death

without

inflammation

and

immune response

No more valid equation!

• Apoptosis can occur also without activation of caspases, caspases can also be activatedin other cell death modalities

• Cells dying by apoptosis can induce inflammation and immune response

• Existence of other forms of regulated cell death (necroptosis and autophagic cell death)

Programmed

(regulated)

cell deathApoptosis

activation

of caspases

silent death

without

inflammation

and

immune response

No more valid equation!

Reviewed by Kepp et al., 2011, Cancer Metastasis Rev 30:61-69.

Tumour cells dying after exposure to antracyclins (for example doxorubicin, mitoxantrone),

oxaliplatin or ionizing radiation can induce strong anticancer immune response

Calreticulin (CRT) at the plasma membrane of dying cell

– “eat me signal” for antigen presenting dendritic cells

Priming of

CD4+ and CD8+

lymphocytes,

anti-tumor response

Programmed

(regulated)

cell deathApoptosis

activation

of caspases

silent death

without

inflammation

and

immune response

No more valid equation!

Kroemer et al., 2013, Annu. Rev. Immunol. 31:51-72.

ICD immunogenic cell death; DC, dendritic cell;

CTL, cytotoxic T-cell lymphocytes; CRT, calreticulin

Immunogenic Cell Death (ICD) – determines the long-term success of anticancer therapy

Suboptimal regimens(without inducing ICD)

Alterations in cancer cells(preventing emission of immunogenic signals)

Defects in the immune effectors(abolishing the perception of ICDby the immune system)

All contributeto therapeutic failure

Accidental

cell deathNecrosis

cell death

with

inflammation

In some cases (inhibition of caspases) stimulation of cells with death ligands (CD95, TNFalpha, TRAIL) leads to necrosis = necroptosis – regulated, active process

Passive process

not always!

Programmed

(regulated)

cell deathApoptosis

activation

of caspases

silent death

without

inflammation

and

immune response

No more valid equation!

Necroptosis, parthanatos, oxytosis, ferroptosis, NETosis, pyronecrosis and pyroptosis

Berghe et al., Nat Rev Mol Cell Biol. (2014) ;15(2):135-47.

RIPK1/3: receptor-interacting protein kinase 1/3

MLKL: mixed lineage kinase domain-like

Emerging pathways of regulated necrosis

Tentative forms of regulated necrosis

NecroptosisPyroptosisEntosisParthanatosNetosis

Autophagy: Renovation of cells and tissues

Major intracellular degradation system by which cytoplasmic materialsare delivered to and degraded in the lysosome

The purpose of autophagy is not the simple elimination of materials, instead it serves asdynamic recycling system that produces new building blocks and energyfor cellular renovation and homeostasis

Essential role in:

•metabolic adaptation (starvation)

•intracellular quality control (degradation of damaged mitochondria)

•renovation during development (after fertilization maternal proteins and RNAs are extensively degradedwhile new proteins encoded by the zygotic genome are synthesized)

•differentiation (lineage differentiation: adipocytes, erythrocytes, T-cells)

•Impairment or activation of autophagy contributes to pathogenesis of diverse diseases

Mizushima & Komatsu, Cell 2011, 147: 728-740

Kroemer & Levine, Nat. Rev. Mol. Cell Biol. 2008 Dec;9(12):1004-10

In mammals autophagy is usually a self-

limiting process that protects cells from death

and is essential for tissue homeostasis.

mammalian cells die usually either by

necrosis (necroptosis) or apoptosis.

presence of the autophagosomes usually only

accompany cell death - cell death with

autophagy

real autophagic cell death

There are only few known examples of cell

death that can be prevented by genetic

inhibition of autophagy in mammals

in lower organisms, several developmental

processes

(salivary gland involution in the larvae of

Drosophila, excitotoxic cell death of

Caenorabditis elegans neurons)

Autophagic cell death

Galluzzi et al., Cell Death Differ., 2015 Jan;22(1):58-73.

Regulated cell death

cell death occuring by dedicated molecular machinery,can be inhibited by targeted pharmacologicaland/or genetic intervention

Cell death modalities today

Apoptosis (extrinsic and intrinsic pathways)Autophagic cell death / cell death with autophagyNecroptosis (maybe some other forms) - regulated necrosis

Accidental cell death

cell death triggered by extremely harsh physical conditions,cannot be inhibited by pharmacological and/or genetic manipulations

Necrosis

Programmed cell death – cell death occuring without any exogenous perturbations –hence operating as a physiological program in development or tissue turnover

Apoptosis

Apoptosis

intrinsic

caspase-

-dependent

extrinsic

death receptors dependence receptors

caspase-

-independent

caspase-

-dependent

inducing signal executing machinery

Apoptosis

Apoptosis

intrinsic

caspase-

-dependent

extrinsic

death receptors dependence receptors

caspase-

-independent

caspase-

-dependent

inducing signal executing machinery

Caspases – the motors of Apoptosis

Proteases

Cysteine in active centerCleave proteins after Aspartate(Cysteine Aspartase)

Present in the cytoplasm as inactive forms- Procaspases

Caspases are activated via:

1. autocatalysis2. transactivation by other caspases3. proteolysis by other proteases

(Granzyme B, Cathepsin G)

Initiator caspases

Pro-apoptotic stimulus

Effektor caspases

Caspasecascade

Apoptosis

Caspase – Family

p10p20CARD

p20CARD

p20CARD

p20CARD

p20CARD

p20CARD

p20DEDDED

p20DEDDED

p20N-

p20N-

p20N-

p20CARD

p10

p10

p10

p10

p10

p10

p10

p10

p10

p10

p10

Caspase-1

Caspase-4

Caspase-5Caspase-13

Caspase-2

Caspase-9

Caspase-8

Caspase-10

Caspase-3

Caspase-6

Caspase-7

Caspase-14

InflammationActivation of cytokines

Apoptosis

Differentiation

RegulatoryDomain

CatalyticDomain

CARD, caspase recruitment domain; DED, death effector domain; N, N terminal peptide

Apoptotic Caspases are classified as Initiator- or Effector-Caspases

p10p20CARDp20CARDp20DEDDEDp20DEDDED

p10p10p10

Caspase-2Caspase-9Caspase-8Caspase-10

p20N-p20N-p20N-

p10p10p10

Caspase-3Caspase-6Caspase-7

Initiator-Caspases:

Effector-Caspasen:

CARD, caspase recruitment domain; DED, death effector domain; N, N terminal peptide

p20DEDDEDp20DEDDED

p10p10

cleavage sites

p20

p20p10 p10

Active tetramer cleaves other caspasesand initiates cell death signaling

Effector-Caspases cleave cytoplasmicand nuclear substrates

Cell death

Pro-caspases

Apoptosis

Apoptosis

intrinsic

caspase-

-dependent

extrinsic

death receptors dependence receptors

caspase-

-independent

caspase-

-dependent

inducing signal executing machinery

Intrinsic Apoptosis

Apoptosis

intrinsic

caspase-

-dependent

caspase-

-independent

inducing signal executing machinery

Organelle-specific initiation of cell death

Nucleus – DNA damage, mitotic problems

Mitochondrium – Central regulator of cell death

hypoxia, respiratory chain inhibitors

Conditions that imbalance protein homeostasis (UPR)

Microbial stimuli

ER – UPR

Cytoskeleton – perturbations of the microtubular or actin network

Cellular Stress

Growth factor deprivation

Chemotherapeutics

Ashkenazi A. Nat Rev Cancer 2002;2:420–430, modified

APAF1, apoptotic protease activating factor-1; BAK, BCL2 homologous antagonist/killer; BAX, BCL2-associated protein; BCL2, B-cell

chronic lymphocytic leukemia/lymphoma 2; PUMA, p53-upregulated modulator of apoptosis;

Intrinsic apoptosis

Cellular Stress

Growth factor deprivation

Chemotherapeutics

Chemotherapy

Radiotherapy

Caspase 3, 6, 7

Apoptosis

p53

BAX, BAK

Mitochondria

p53

Caspase 9

DNA damage

PUMA, NOXA

p53

APAF1

Cytochrome c

DNA damage

SMAC/DIABLO

Organelle-specific initiation of cell death

Nucleus

Mitochondrium

ER

Cytoskeleton

inducing signal

Ashkenazi A. Nat Rev Cancer 2002;2:420–430, modified

APAF1, apoptotic protease activating factor-1; BAK, BCL2 homologous antagonist/killer; BAX, BCL2-associated protein; BCL2, B-cell

chronic lymphocytic leukemia/lymphoma 2; PUMA, p53-upregulated modulator of apoptosis;

Intrinsic apoptosis

Cellular Stress

Growth factor deprivation

Chemotherapeutics

Apoptosis

Apoptosis

intrinsic

caspase-

-dependent

extrinsic

death receptors dependence receptors

caspase-

-independent

caspase-

-dependent

inducing signal executing machinery

Extrinsic apoptosis

Activation of effector caspases

Apoptosis

death receptor

death ligand dependence receptor

Dependence receptors have two faces:In the presence of ligand – transduction of a positive signalIn the absence of ligand – induction of apoptosis

All are cleaved by caspasesAll contain an ADD (addiction/dependance domain)After exposition of ADD by receptor cleavage ADD recruits additional caspase-activating complexes

Dependence Receptors

Goldschneider & Mehlen, Oncogene 2010, 1865-1882

Death Receptors

TNF FasL TL1A TRAIL ? NGFEDA1

DR4 DR5 DcR2 DcR1

Cysteine-rich motif

Death domain

TL1, TNF-like cytokine;

EDAR, Ectodermal displasia receptor

EDA1, Ectodysplasin A1

NGF, Nerve growth factor

Physiological function of Death Receptors (CD95 & TRAIL-Rs)

TRAIL-R1/R2

TRAIL

NK

CTL

tumor cellCD95

NK

CTL

TNFRI – mainly inflammation

tu mor

cell

TRAIL-R1/R2

TRAILNK

CTL

tumor cellCD95

CD95L

NK

CTL

CD95L

TRAIL-R1/R2

TRAILNK

CTL

CD95

CD95L

NK

CTL

Ashkenazi A. Nat Rev Cancer 2002;2:420–430, modified

DR, death receptor; DL, death ligand; FADD, Fas-associated death domain;

Caspase 3, 6, 7

Apoptosis

FADDProcaspase 8, 10

Caspase 8, 10

Death receptor-mediated apoptosis

Type I-CellsDISC

DR

DL

DR

Ashkenazi A. Nat Rev Cancer 2002;2:420–430, modified

APAF1, apoptotic protease activating factor-1; BID, BH3-interacting domain death agonist; DR, death receptor; FADD, Fas-

associated death domain;

Caspase 3, 6, 7

Apoptosis

FADDProcaspase 8, 10

Caspase 9

Caspase 8, 10

t-BID

Mitochondria

Cytochrome c

BID

APAF1

DISC

BAX, BAK

Type II-Cells

Death receptor-mediated apoptosis

DR

DL

DR

Ashkenazi A. Nat Rev Cancer 2002;2:420–430, modified

APAF1, apoptotic protease activating factor-1; BAK, BCL2 homologous antagonist/killer; BAX, BCL2-associated protein;; BID, BH3-

interacting domain death agonist; DR, death receptor; FADD, Fas-associated death domain; PUMA, p53-upregulated modulator of

apoptosis;

Caspase 3, 6, 7

Apoptosis

death receptor ligand TRAIL

FADD

Cell-extrinsic

pathway

Procaspase 8, 10

p53p53

Caspase 9

Caspase 8, 10

p53

BAX, BAK

Mitochondria

Chemotherapy

Radiotherapy

DNA damage

PUMA, NOXA

APAF1

Cytochrome c

DNA damage

BID

Cell-intrinsic

pathway

Intrinsic and extrinsic apoptotic pathways are linked

t-BID

TRAIL-R1

TRAIL-R2

Ashkenazi A. Nat Rev Cancer 2002;2:420–430, modified

APAF1, apoptotic protease activating factor-1; BID, BH3-interacting domain death agonist; DR, death receptor; FADD, Fas-

associated death domain;

Each step of the apoptotic pathway is tightly controlled

TRAIL

Caspase 3, 6, 7

Apoptosis

FADD

Procaspase 8, 10

Caspase 9

Caspase 8, 10

t-BID

Mitochondria

Cytochrome c

BID

APAF1

BCL2, BCLXL, MCL1

SMAC/DIABLO

IAP

FLIP

BAX, BAK

DISC

Decoy-Receptors

TRAIL-R1

TRAIL-R2

Decoy-receptors diminish DISC-formation

DcR: Decoy Receptor; OPG: Osteoprotegerin

OPG – soluble Receptor for TRAIL

DcR1 - membrane-anchored TRAIL-R

DcR2 - TRAIL-R with truncated DD

Lemke et al., Cell Death Differ. 2014, 1-15

Ashkenazi A. Nat Rev Cancer 2002;2:420–430, modified

APAF1, apoptotic protease activating factor-1; BID, BH3-interacting domain death agonist; FADD, Fas-associated death domain;

FLIP

Caspase 3, 6, 7

Apoptosis

FADD

extrinsic

pathway

Procaspase 8, 10

Caspase 9

Caspase 8, 10

t-BID

Mitochondria

Cytochrome c

BID

FLIP inhibits DISC-activity

APAF1

BCL2, BCLXL, MCL1

SMAC/DIABLO

IAP

FLIP

BAX, BAK

FLIP – Caspase-8-homologueMutation in active center

DISC

DR

DL

DR

Ashkenazi A. Nat Rev Cancer 2002;2:420–430, modified

APAF1, apoptotic protease activating factor-1; BID, BH3-interacting domain death agonist; DR, death receptor; FADD, Fas-

associated death domain;

Caspase 3, 6, 7

Apoptosis

FADD

Procaspase 8, 10

Caspase 9

Caspase 8, 10

t-BID

Mitochondria

Cytochrome c

BID

Members of the Bcl-2-Family regulate intrinsic pathway and extrinsic pathway in Type II-cells

APAF1

BCL2, BCLXL, MCL1

SMAC/DIABLO

IAP

FLIP

BAX, BAK

DISC

DR

DL

DRType II-Cells

extrinsic

pathway

intrinsic

pathway

The Bcl-2-Family

BH: Bcl-2 homology domain

Guardians

critical for cell survivalanti-apoptotic functions

Effectors

upon activation Bax/Bak mediate MOMPactivation of effector stages of apoptosis

Sensors

essential for initiation of apoptosis signaling

Bax and Bak form poresin the outer mitochondrial membrane

Bcl2 and Bcl-xL inhibit Bax and Bak

BH3-only proteins influence these processes

The Bcl-2-Family

Ashkenazi A. Nat Rev Cancer 2002;2:420–430, modified.

APAF1, apoptotic protease activating factor-1; BID, BH3-interacting domain death agonist; DR, death receptor; FADD, Fas-

associated death domain;

Caspase 3, 6, 7

Apoptosis

FADD

extrinsic

pathway

Procaspase 8, 10

Caspase 9

Caspase 8, 10

t-BID

Mitochondria

Cytochrome c

BID

APAF1

BCL2, BCLXL, MCL1

SMAC/DIABLO

IAP

FLIP

BAX, BAK

DISCP

CKI/II

Phosphorylation of Bid inhibits its proteolytic cleavage

Type II-Cells

DR

DL

DR

Ashkenazi A. Nat Rev Cancer 2002;2:420–430, modified.

APAF1, apoptotic protease activating factor-1; BID, BH3-interacting domain death agonist; DR, death receptor; FADD, Fas-

associated death domain;

Caspase 3, 6, 7

Apoptosis

Pro-apoptotic ligand

FADD

DR5

DR4

extrinsic

pathway

Procaspase 8, 10

Caspase 9

Caspase 8, 10

t-BID

Mitochondria

Cytochrome c

BID

IAPs inhibit caspases, inactivated by SMAC

APAF1

BCL2, BCLXL, MCL1

SMAC/DIABLO

IAP

FLIP

BAX, BAK

DISCP

CKI/II

intrinsic

pathway

IAP-Family

IAP: Inhibitors of Apoptosis; BIR: Baculoviral IAP Repeat; CARD: Caspase Activation and Recruitment Domain;

RING: RING zing finger; NOD: Nucleotide-binding Oligomerization Domain; LRR: Leucine Rich Repeat

Model for XIAP-mediated regulation of apoptosis

Healthy cells or cell that

were subjected to sub-lethal

apoptotic stimulus

XIAP binds and inhibits

caspases

Auto-ubiquitination of XIAP

Ubiquitination of caspases

Proteasomal degradation

Cells which were subjected to lethal

apoptotic stimulus

SMAC and Omi released from

mitochondria bind and inhibit

XIAP (and other IAPs)

Auto-ubiquitination of XIAP

Ubiquitination of SMAC/Omi

Proteasomal degradation

of the complex

Massive activation

of free caspases

Ashkenazi A. Nat Rev Cancer 2002;2:420–430, modified

Apoptosis – a tightly controlled cell death programimportant for tissue homeostasis

TRAIL

Caspase 3, 6, 7

Apoptosis

FADD

Procaspase 8, 10

Caspase 9

Caspase 8, 10

t-BID

Mitochondria

Cytochrome c

BID

APAF1

BCL2, BCLXL, MCL1

SMAC/DIABLO

IAP

FLIP

BAX, BAK

DISC

Decoy-Receptors

TRAIL-R1

TRAIL-R2

Immune survaillance

Cellular Stress

Growth factor deprivation

DNA damage

Resistance to apoptosis is a hallmark of cancer

Wong, J. Exp. Clin. Cancer Res. 2011;30:87.

Resistance to apoptosis is a hallmark of cancer

Induction of apoptosisis the aim of many anti-tumor therapies

Wong, J. Exp. Clin. Cancer Res. 2011;30:87.

Ashkenazi A. Nat Rev Cancer 2002;2:420–430, modified

Apoptosis in anti-tumor therapy – two main strategies

Caspase 3, 6, 7

Apoptosis

death receptor ligand TRAIL

or agonistic antibodies

FADD

Targeting

extrinsic

pathway

Procaspase 8, 10

Caspase 9

Caspase 8, 10

p53

BAX, BAK

Mitochondria

PUMA, NOXA

APAF1

Cytochrome c

DNA damage

BID

t-BID

TRAIL-R1

TRAIL-R2 Chemotherapy

Radiotherapy

p53p53

DNA damage

Targeting

intrinsic

pathway

Targeting the intrinsic apoptosis pathway

Caspase 3, 6, 7

Apoptosis

FADD

Procaspase 8, 10

Caspase 9

Caspase 8, 10

p53

BAX, BAK

Mitochondria

PUMA, NOXA

APAF1

Cytochrome c

DNA damage

BID

t-BID

TRAIL-R1

TRAIL-R2 Chemotherapy

Radiotherapy

p53p53

DNA damage

Targeting

intrinsic

pathway

IAP

BCL2, BCLXL, MCL1

Cancer: Disrupted balance of Bcl-2 family of proteins, overexpression of IAPs,

mutated or non-functional p53

Ashkenazi A. Nat Rev Cancer 2002;2:420–430, modified.

X

X

Caspase 3, 6, 7

Apoptosis

FADD

Procaspase 8, 10

Caspase 9

Caspase 8, 10

p53

BAX, BAK

Mitochondria

PUMA, NOXA

APAF1

Cytochrome c

DNA damage

BID

t-BID

TRAIL-R1

TRAIL-R2 Chemotherapy

Radiotherapy

p53p53

DNA damage

Targeting

intrinsic

pathway

IAP

BH3 mimetics

SMAC mimetics

BCL2, BCLXL, MCL1

SMAC/DIABLO

Targeting the intrinsic apoptosis pathway

Ashkenazi A. Nat Rev Cancer 2002;2:420–430, modified.

Restoring the wt

conformation

Inhibition of MDM2-p53

Caspase 3, 6, 7

Apoptosis

FADD

Procaspase 8, 10

Caspase 9

Caspase 8, 10

p53

BAX, BAK

Mitochondria

PUMA, NOXA

APAF1

Cytochrome c

DNA damage

BID

t-BID

TRAIL-R1

TRAIL-R2

Ashkenazi A. Nat Rev Cancer 2002;2:420–430, modified.

Targeting the extrinsic apoptosis pathway

death receptor ligand TRAIL

or agonistic antibodiesextrinsic

pathway

X

TRAIL induces death preferentially in tumor cells (clinical trials), p53 independent!

Tumor cells develop multiple, parallel operatingapoptosis-inhibiting strategies

The misused Death Receptors

Constitutive apoptosis-resistance mechanisms in PDAC cells

BclxL

TRAF2

FLIP

XIAP

c-IAP1/2

Hinz et al., Oncogene 2000

Trauzold et al., Oncogene 2001

Trauzold et al., Br. J. Cancer 2003

Trauzold et al., Faseb J. 2005

Antibody

ApoptosisTRAIL-R1/R2

TRAIL

TRAIL induces death preferentially

in tumor cells (clinical trials)

BH3 mimetics

SMAC mimetics

Trauzold et al., Oncogene 2006

Exogenous TRAIL induces metastasis

(via TRAIL-R1)

Endogenous TRAIL induces metastasis

(via TRAIL-R2) in KRAS-mutated cells

von Karstedt et al., Cancer Cell 2015

Trauzold et al., Oncogene 2001

Siegmund et al., Cell Signal 2007

Lemke et al., J Mol Med 2010

Ehrenschwender et al., Cell Death Diff 2010

Invasion instead of Apoptosis - new Function of death receptors in PDAC (and many other) tumor cells

+ sensitizing agents

+ inhibitors

Current TRAIL-based anti-tumor therapy

•Enhancement of cell sensitivity

•Inhibition of non-apoptotic signaling

•Inhibition of TRAIL?

Apoptosis

Proliferation

Inflammation

Migration/Invasion

Metastasis

Bcl-xL

IAPs

FLIP

Tumor cell

TRAIL-R1/R2

TRAIL

Antibody

High intracellular levels of TRAIL-Receptors correlate with poor prognosis

• Tumor cells express TRAIL receptors mainly in intracellular locations

• high intracellular levels of TRAIL-R2 correlate with poor prognosis

TRAIL-R1 TRAIL-R2

Haselmann et al, … Hauser, Egberts,…..& Trauzold: Gastroenterology, 2014

Bertsch,…, Trauzold; Cell Death & Disease, 2014

nuclear TRAIL-R2 has an oncogenic function

Haselmann et al., Gastroenterology 2014

Tumor cells express TRAIL-Rs mainly intracellularly

Nuclear TRAIL-R2 enhances tumor growth and metastasis

Breast cancer bone-metastasis model

Fritsche et al., Oncotarget 2015

Orthotopic PDAC xenotransplantation model in mouse

Haselmann et al., & Trauzold, Gastroenterology 2014

KD of TRAIL-R2 : HMGA2 myc CXCR4 E-cadherin

Future TRAIL-R-based anti-tumor therapy

Plasma membrane TRAIL Receptors

• enhancement

• sensitisation

• inhibition of non-apoptotic signaling

or

• inhibition of TRAIL-R

• neutralisation of endogenous TRAIL

nuclear TRAIL-R2

• inhibition of the nuclear import

• enhancement of the export

• inhibition of the nuclear functions

Tumor cell

TRAIL-R1/R2

TRAIL

Antikörper

Cell death

Hanahan & Weinberg, 2011, Cell 144: 646-674

Efficient induction and successful execution of cell deathis the aim of many anti-tumor therapies

The paradox of cell death-driven cancer

Labi & Erlacher, Cell Death and Disease (2015) 6, e1675; doi:10.1038/cddis.2015.20

Pro-oncogenic effects of apoptotic cell death

Ichim & Tait, Nature Review Cancer (2016) 16: 539-548.

iPLA2 – calcium-independent phospholipase A2; COX – Cyclooxygenase

„eat me and find me“ signals FKN – fractalkine, ATP, LTF lactotrasferrin

Dying cells affect their surrounding environment in various, yet not fully understood, ways

Stimulate angiogenesis

tumor cell motility

dissemination

Current strategies: Enhancing apoptosiswhile minimizing damage

Ichim & Tait, Nature Review Cancer (2016) 16: 539-548.

CSF1 – Colony stimulating factor 1 receptor, main trophic support factor for macrophages

cell death and cancer

Besides apoptosis, other forms of cell death similarly affect cancer in multifaceted manner

(necrotic cell death – inflammation – tumor promoting and inhibiting effects)

„Improved understanding of the role of cell death in cancer will enable us

to fully harness ist potential as a therapeutic target“

Ichim & Tait, Nature Review Cancer (2016) 16: 539-548.

Exam questions examples: multiple choice

Which answer regarding so called Type II cells is correct?

a) Apoptosis is independent of caspase-8.

b) Apoptosis is independent of mitochondria.

c) Cell death can be inhibited by the overexpression of Bcl-xL.

d) Cytochrome c activates caspase-8 in the DISC.

e) Apoptosis can be inhibited by the overexpression of Bax.

Exam questions examples: free text

1. Please name the cellular organelles, which can act as initiators of the

intrinsic apoptotic cell death (2 Points). Please provide at least one example

per organelle of such organelle-specific death-triggering event (2 Points).

2. Please draw the scheme of TRAIL-mediated apoptotic cell death pathway

in Type I cells (2 Points). Name at least 4 possible anti-apoptotic

mechanisms (2 Points).