Giampaolo Tortora
Microambiente e risposta immunitaria
Cattedra di Oncologia Medica UOC Oncologia
Scuola di Medicina e Chirurgia e
Azienda Ospedaliera Universitaria Integrata Verona
Relevant signalling pathways in PDAC
Witkiewicz AK et al., Nature Comm Apr. 2015
Classes and gene programmes of PDAC
Bailey P. et al. Nature , 2016
• Cosa c’è nello stroma ? Non solo fibrosi
• Microambiente tumorale e pathways infiammatorie
• Risposta immunitaria condizionata da stroma, microambiente e pathways di segnale infiammatorie
Stroma e Microambiente:
difensori o complici del tumore ?
Adenocarcinoma del Pancreas:
una cicatrice con pochi vasi
Courtesy Prof. Aldo Scarpa
Albrech Nesse, Univ Goettingen
Key components of stromal microenvironment in PDAC
Enzymatic targeting of the stroma
Provenzano PP et al, Cancer Cell, 2012
Hyaluronic Acid (Hyaluronan):
• large linear glycosaminoglycan, composed of repeating N-acetyl glucosamine and glucuronic acid units
• figures prominently in the architecture, integrity, and malleability of tissues
• embryogenesis and oncogenesis
PEGPH20 (PEGylated Recombinant Human Hyaluronidase)
• PDAC exhibit different levels of stroma
• High stromal density is associated with longer DFS and OS in patients resected and receiving adjuvant therapy
• EMT reduces ENT1, ENT2 and CTN, thus preventing gemcitabine activity, regardless of its ability to penetrate through the fibrosis.
• Production of Fibroblast activated protein (FAP) alfa is common to: PDAC stroma, fibrosis, cyrrhosis.
• Distinct, heterogeneous populations of fibroblasts and myofibroblasts, their role may be context-dependent.
The Stroma dilemma: How to Reconciliate the
contradictions for therapeutic purposes
Jorgensen-Tape, based on Cell, 2016
• Dichotomous pro-tumor and anti-tumor properties of stroma in PDAC.
• Stromal cells activation by other (nearby ?) cells can influence tumors growth and progression.
• Total stromal ablation increases malignant behavior; therefore, ‘‘stromal reprogramming’’ is more desirable to provide therapeutic benefit in PDAC.
The Stroma dilemma: How to reconcile the
contradictions for therapeutic purposes
• PD1/PDL-1 Checkpoint inhibitors are ineffective
• Activity of pembro only in MMR deficient tumors (1% of PDAC)
• Resistance also to CAR T cells treatment
• Cold tumors
• In spite of the many mutations PDAC make very little neoantigens.
Immune response in PDAC : frustration !
Risposte agli inibitori di immunocheckpoint in melanoma e PDAC
Le DT et al., N Engl J Med. 2015 Jun 25;372(26):2509-2520.
The 17 non CRC MMR deficient tumors included 4 (23%) PDAC and 4 (23%) Ampullary tumors.
But… ICGC data show that MMR is present in only 1% of PDACs !
PDAC is immunologically quiescent and infiltrated with immune suppressive
regulatory T cells
50% of Melanomas have spontaneous infiltration of effector T cells that can
respond to checkpoint inhibitors
Why does not current immunotherapy work on PDAC?
FoxP3 TRegs
Stroma CD8+ T cells
Melanoma PDAC
Tumor suppression and Imbalancement of immune response
Desmoplastic reaction: myofibroblasts, pancreatic Stellate cells, Treg, MDSC, etc.
A strongly immune resistant and suppressive environment
Immune Suppression
Immune activation
Mace TA et al., Oncoimmunology. 2013 2:e24891;
• Chemokines and their receptors play a critical role in conditioning metastatic niche, immunesuppressive status and tumor microenvironment.
• Chemokines help to recruit to tumor side and to «corrupt» neutrophils (TANs), monocytes/macrophages (TAMs) and fibroblasts with different properties which, altogether, help tumor growth and metastatic spreading.
Inflammatory cytokines, Chemokines and their receptors
Chemokine receptor
Ligands Expressing/target Cells
CXCR1 CXCL6 and 8 (alias IL-6, IL-8) neutrophils
CXCR2 CXCL1 to CXCL7 neutrophils
CXCR4 CXCL12 (SDF-1) neutrophils, monocytes, macrophages, B and T cells,
dendritic cells
CCR2 CCL1 (monocytes
chemoattractant protein)
monocytes
Cancer cell-intrinsic and -extrinsic clues to inflammation and fibrosis.
• Pro-inflammatory IL1 produced by tumor cells or hijacked adipocytes activate PSC, which further amplify this loop by an independent IL1 cytokine release.
• Recruited neutrophils extensively interact with other cellular components of the stroma (i.e., adipocytes and PSC), creating a highly fibrotic and poorly vascularized tissue environment, refractory to drug diffusion and hostile to activation of tumor-specific CD8+ T cells
Incio et al., Cancer Discovery 2016
Bronte V. and Tortora , Cancer Discovery August 2016
IL1-α induces a metastatic phenotype in PDAC by sustaining a constitutive activation of NF-B
Grivennikov, Greten, Karin Cell 2010 Niu J, et al. J Biol Chem. 2004 Melisi D, et al. Mol Cancer Research. 2009
Cytokines levels affect OS and DFS of PDAC patients
Piro G et al., Oncoimmunology 2017, VOL. 6, e1322242
OS and DFS of patients with resectable PDAC stratified according to cytokines
levels in plasma samples
Cytokines levels affect OS and DFS of PDAC patients
Piro G et al., Oncoimmunology 2017, VOL. 6, e1322242
Patients stratified for DFS on the basis of simultaneous expression
of low IL4 and high TNFa
Slide 23
Gregory Beatty , 2017 ASCO Annual Meeting
CXCR2 inhibition enhances T cell entry and confers sensitivity to anti-PD1 therapy.
Steele CW et al., Cancer Cell 29, 1–14, June 13, 2016
CXCR2 in metastatic niche and sensitivity to immunetherapy
• CXCR2 signaling is upregulated in MDSCs and in pancreatic cancer
• Neutrophils and MDSCs play a key role in setting the metastatic
niche: their CXCR2 expression at tumor borders correlate with poor prognosis .
Phase 1b trial of CCR2 inhibitor of TAMs plus FOLFIRINOX in borderline resectable and locally advanced PDAC
Nywening T et al., Lancet Oncology 17:651-662
Effect of FOLFIRINOX plus PF-04136309 treatment on TAMs in the tumor microenvironment
Effect of CCR2 blockade on mobilisation of bone-marrow- derived inflammatory monocytes into the peripheral circulation
The CCL2–CCR2 chemokine axis is used to recruit TAMs for construction of an immunosuppressive tumour microenvironment
Oezdemir et al, Cancer Cell 2014
CAF depletion induces immunosuppression and sensitize to immunetherapy
• CXCL12 (SDF1) may be responsible: it is expressed only by FAP+ CAF cells and does not bind to CXCR4 on cancer cells but on T cells (CXCR4+ and PD1+) !!
Tumor
microenvironment and novel
therapeutic agents
Krantz et al., Chin. Clinical Oncology, Vol 6, No 3 June 2017
Immunotherapy challenge in PDAC:
How to convert a
non-immunologic tumor into
an immune responsive disease
VACCINES
GVAX/Listeria chemo
RT Targeted agents
PD-1/ PD-L1 CTLA-4
CHECKPOINT BLOCKADE
TME INHIBITORS/
RE-EDUCATORS
Modified from R. Vonderheide
Combination Therapy Strategy for Less Immunogenic Tumors
Targeting TβRI inhibits metastatic processes in pancreatic cancer
Melisi D, et al. Mol Cancer Ther. 2008
• Adoptive transfer of TGFBR-deficient CD8+ T cells led to enhanced infiltration and granzyme B–mediated destruction of developing tumors.
• Parallel observations in human patients, where TGFβ expression correlated with increased fibrosis and associated negatively with
expression of granzyme B.
• Therefore, despite opposing some epithelial cells proliferation, TGFβ may promote PDAC development by affecting stromal and
hematopoietic cell function.
• Strategy: TGFBR inhibition to target components of tumor microenvironment particularly in patients who have lost tumor- suppressive TGFβ signals in the epithelium.
TGFβR deficiency promotes a cytotoxic response against pancreatic lesions
Principe DR et al., Cancer Res, 2016
Global TGFBR deficiency promotes a cytotoxic response against pancreatic lesions.
H9H-MC-JBEG
A Phase 1b study of Galunisertib with the anti-PD-L1
Durvalumab in Recurrent or Refractory Metastatic PDAC
Bailey P et al Nature March 2016
Molecular classes and transcriptional networks of PDAC
Unsupervised analysis of RNAseq identified :
• Squamous
• ADEX (Abnormally Differentiated Endocrine eXocrine)
• Pancreatic progenitor
• Immunogenic
4 classes based on transcription factors and downstream targets. Enriched with specific histological features
Bailey P et al. Nature, March 3 2016
RNAseq profiles identified immune subtypes
• The microenvironment of PDAC includes inflammatory cells, PSCs, cytokines/chemokines and “specialized” types of fibroblasts that, in an
organized fashion, contribute to build up desmoplasia and to create conditions for a privileged immune-escape environment and for the metastatic spreading.
• Very likely the current checkpoint inhibitors will not produce results unless the microenvironment is “converted” and reconditioned.
• Inflammatory cytokines and receptors and TGFb pathway are relevant targets for microenvironment conditioning.
