Preclinical efficacy model to promote immunotherapy development for prostate cancer
AACR 2017
#1663
Mari I. Suominen1, Tiina E. Kähkönen1, Yvonne Konkol1, Jenni Mäki-Jouppila1, Jussi M. Halleen1 and Jenni Bernoulli1
1Pharmatest
Services Ltd., Finland – Email Correspondence to [email protected]
Introduction
A.
B.
Prostate weights (g) after 6, 13 and 18 weeks of hormonal exposure
***
***
2.0
C.
Pituitary weights (g) after 6, 13 and 18 weeks of hormonal exposure
0.06
***
A.
Number of inflamed acini in dorsolateral prostate
after different hormonal exposure times
B.
C.
***
30
***
0.04
n
mg
1.5
mg
Immunotherapy for prostate cancer has recently emerged as an attractive
treatment strategy. Yet, preclinical models where relationship between
inflammation, stroma, tumor cells and prostate cancer progression can be
studied are limited. In the present animal models, mainly human cancer cells
are used in immunocompromised animals and interaction between the
immune system and cancer cannot be monitored in these models due to the
lack of active immune system.
Results
20
NS
1.0
0.02
Models with normal immune system include syngeneic models, where murine
cancer cell lines are used, genetically engineered models and models where a
known carcinogen is applied. In the presented model, no known oncogenic
mutations or carcinogens are used, thus underlying the importance of
inflammation in the development of cancer.
As the requirement to test novel immunotherapies and especially combination
treatments is increasing, a preclinical model that takes into account tumor
microenvironment and immune system would be highly useful to promote
development of novel therapies to combat against prostate cancer.
10
0.5
0.0
0.00
Placebo (13 wk)
6 wk T+E2
18 wk T+E2
Placebo (13 wk)
6 wk T+E2
13 wk T+E2
18 wk T+E2
6 wk T+E2
13 wk T+E2
18 wk T+E2
Figure 1. Hormonal treatment increased estradiol to testosterone ratio, and caused increase in weight of hormonal sensitive organs A) prostates and B) pituitary
glands after all treatment periods 6, 13 and 18 weeks. C) Extent of chronic inflammation in dorsolateral prostate lobes increased concurrently with treatment
period length.
Aim of the Study
Aim of the present study was to reveal if there is role between the immune
system and development of prostate cancer, and secondly, to validate an
animal model to be utilized in immunotherapy development.
13 wk T+E2
0
Placebo
6 week T+E2
A.
13 week T+E2
B.
200µm
C.
E.
F.
200µm
G.
200µm
200µm
H.
2.
Yatkin E, Bernoulli J, Lammintausta R, Santti R. Fispemifene [Z-2-{2-[4-(4-chloro-1,2-diphenylbut-1-enyl)phenoxy]ethoxy}-ethanol], a novel selective estrogen receptor modulator, attenuates glandular inflammation in
an animal model of chronic nonbacterial prostatitis. J Pharmacol Exp Ther. 2008 Oct;327(1):58-67
Bernoulli J, Yatkin E, Konkol Y, Talvitie EM, Santti R, Streng T. Prostatic inflammation and obstructive voiding
in the adult Noble rat: impact of the testosterone to estradiol ratio in serum. Prostate. 2008 Sep
1;68(12):1296-306.
C.
200µm
Figure 4. Macrophages specific for CD163 (M2 type macrophage) were present in
both prostate (A) and periurethral side (B+C). A) In the prostate M2 cells were present
only in the stromal compartment without inflammatory foci. M2 cells were absent in
inflamed prostatic acini. M2 cells were abundant in the periurethal stromal areas but
absent in B) PIN-like lesion areas or C) or at the adenocarcinoma site.
Conclusions
200µm
References
1.
B.
D.
200µm
200µm
A.
18 week T+E2
Materials and Methods
Intact 10-12 weeks old male Noble rats were s.c. implanted with slow-releasing
testosterone and estradiol pellets (Innovative Research of America, Florida) for 6, 13
and 18 weeks. Estimated daily release for testosterone was 0.8 mg and for estradiol
0.08 mg. Control group animals received placebo hormone pellets. At the end of the
study, prostates and selected tissues were removed and weighted. Prostate-urethra
blocks were processed and serial paraffin sections were cut for histopathological
evaluation. HE-staining was performed for basic histopathological analysis and
immunostaining using antibodies against CD3+ and CD8+ (monoclonal mouse antirat, Caltag Laboratories, Burlingame, Canada) was used to reveal localization of Tlymphocytes and cytotoxic T cells, respectively. CD163 clone ED2 (Abcam) was
stained (BioSiteHisto Ltd, Tampere, Finland) for M2-type macrophages.
Figure 3. A) Inflammatory foci in prostate consisted mainly of T-lymphocytes (CD3+
cells). B) Specific subset of T-cells, cytotoxic (CD8+) cells were observed in
perivascular lesions. C) Cytotoxic T-cells located also intraepithelially.
Figure 2. Imbalance in hormone-milieu induced inflammation in the prostate mainly in the dorsolateral site (A-D) and in the periurethral area (E-H). Inflammation
was evident as perivascular (arrow in B), stromal (arrow in C) and periglandular (arrow in D) T-lymphocytes and intraluminal (arrow in D) neutrophils. In the
periurethral area formation of prostatic intraepithelial neoplasia (PIN)-like lesions after 13 weeks (G) and finally adenocarcinomas (H) after 18 weeks were
observed. Malignant changes were not observed in placebo-treated (E) or 6 weeks treated (F) prostates.
Presence of lymphocytes in the proximity of PIN-like lesions during the
early phases of prostate cancer, and their disappearance later in the
adenocarcinomas, propose some interaction between innate and
adaptive immune system and cancer. The role of macrophages in the
progress from prostatic inflammation towards cancerous lesions in this
model remains to be revealed.
This preclinical prostate cancer model that combines immune system
and cancer can be utilized when new immunotherapies, combination
treatments and prevention possibilities against prostate cancer
progression are developed.
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