Annals of Oncology

abstracts
has been shown to increase breast cancer risk in postmenopausal women. Our
objective has been to estimate the risk of cancer arising from the common
polymorphism within the 5’ unstranslated region of the leptin gene (-2,548G/A) and
Q223R polymorphisms in the LEPR gen, which has been associated with leptin levels,
in a Mediterranean population.
Methods: The PREDIMED Study is a multi-center, randomized trial aimed at
assessing the effects of the Mediterranean Diet on cardiovascular primary prevention.
We analyzed 1108 participants (404 men and 704 women) high cardiovascular risk
subjects (67 ± 6 years) were selected from a Spanish Mediterranean population.
Demographic, clinical, biochemical, anthropometric, genetic and life-style variables
were obtained.
Results: 84 (7.6%) of the 1108 participants suffered from cancer after a median follow
up of 4.8 years. The group of cancer patients showed 42.9% of current or former
smokers versus 33.9% in the non cancer participants group (p = 0.003). Prevalence of
the -2,548G/A genotypes were: 21.4% GG, 49.7% GA, 28.9% AA (allele frequencies,
G = 0.463 and A = 0.537) and of the Q223R genotypes were: 13.6% QQ, 47.7% QR,
38.7% RR (allele frequencies, Q = 0.375 and R = 0.625). Interestingly, we found a
consistent association of the SNP in the leptin gene with lower cancer risk. The lower
risk of cancer associated with the A allele remained significant (OR = 2.21; 95% CI,
1.04-4.72) after adjustment for gender, age and tobacco smoking.
Conclusions: The allele A in the polymorphism -2,548G/A of the leptin gene is
associated with lower cancer risk in this Mediterranean population.
Clinical trial identification: ISRCTN.org Identifier: ISRCTN35739639
Legal entity responsible for the study: Universitat de València
Funding: Instituto de Salud Carlos III, Ministerio de Sanidad y Consumo
Disclosure: All authors have declared no conflicts of interest.
36P
Radiotherapy-induced apoptotic tumor cells stimulate
proliferation of living tumor cells via caspase 3/7–PKCδ–Akt/
p38 MAPK pathway
J. Cheng 1 , L. Tian 2 , Q. Huang 1
1 The Comprehensive Cancer Center and Shanghai Key Laboratory for Pancreatic
Diseases, Shanghai General Hospital, Shanghai Jiao Tong University School of
Medicine, Shanghai, China, 2 Institute of Translational Medicine, Shanghai General
Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
Background: Our previous studies demonstrated that radiotherapy-induced apoptotic
cells significantly stimulate the proliferation of surviving tumor cells through the
caspase 3-iPLA 2 -AA-PGE 2 pathway. However, the molecular events involved in this
stimulation seem to involve in different pathways. This study seeks to investigate the
molecular mechanisms involved in the stimulatory role of apoptotic human pancreatic
(Panc1) and colonic cancer (HT29) cells in vitro.
Methods: Apoptotic Panc1 and HT29 cells were produced as feeders by 10Gy X-ray
radiation. Caspase 3, 7, PKCδ, Akt, p38 MAPK and JNK1/2 activation was detected by
Western blot. Panc1 and HT29 cells stably transduced by firefly luciferase and green
fluorescent protein fusion gene (Panc1-Fluc and HT29-Fluc) were used as reporter.
Living Panc1-Fluc and HT29-Fluc cells proliferation on radiated Panc1 and HT29 cells
were evaluated by luciferase activity using bioluminescence imaging.
Results: The presence of apoptotic Panc1 and HT29 cells significantly stimulated the
proliferation of living Panc1-Fluc and HT29-Fluc cells. These apoptotic tumor cells
showed significantly increased caspase 3 and 7 as well as PKCδ activity. However,
significant decrease of the stimulation effect on living Panc1-Fluc and HT29-Fluc cells
was observed when apoptotic Panc1 and HT29 cells stably transduced by either
dominant-negative caspase 3, caspase 7 or PKCδ were used as feeders instead; and pan
PKC inhibitor and specific PKCδ inhibitor significantly inhibited the stimulatory effect
of apoptotic Panc1 and HT29 cells. Additionally, significantly increased
phosphorylation of Akt, p38 MAPK and JNK1/2 were observed in the irradiated Panc1
and HT29 cells. Interestedly, dominant-negative PKCδ was resistant to the cleavage
and activation by caspase 3 or 7 and the expression of dominant-negative PKCδ
attenuated radiation induced Akt phosphorylation in both Panc1 and HT29 cells,
attenuated p38 MAPK activation in Panc1 cells.
Conclusions: Apoptotic tumor cells can significantly stimulate the proliferation of
living tumor cells through the caspase 3/7-PKCδ-Akt/p38 MAPK pathway after
radiotherapy.
Legal entity responsible for the study: Qian Huang, Shanghai General Hospital,
Shanghai Jiao Tong University School of Medicine
Funding: National Natural Science Foundation (81120108017, 81172030) and
National Basic Research Program of China (2010CB529902)
Disclosure: All authors have declared no conflicts of interest.
37P
Association of IFNg production and NK cytotoxicity in PBL of
breast cancer patients
S.S. Radenkovic 1 , V. Jurisic 2 , R. Dzodic 3 , G. Konjevic 4
1 Department of Radiation Oncology and Diagnostics, Institute of Oncology and
Radiology of Serbia, Belgrade, Serbia, 2 Department of Pathophysiology, School of
Medicine University of Kraguje, Kragujevac, Serbia, 3 Department of Surgical
Oncology, Institute of Oncology and Radiology of Serbia, Belgrade, Serbia,
4 Department of Experimental Research, Institute of Oncology and Radiology of
Serbia, Belgrade, Serbia
Background: New insights revealed a critical role for endogenously produced IFNγ in
promoting host responses to tumors. In this sense, molecular mechanisms underlying
immune dysfunction that include the role of IFNγ in immune responses are not clearly
defined in breast cancer.
Methods: PBL of breast cancer patients and healthy controls were analyzed for IFNγ
expression and NK cell activity using flow cytometry and 51Cr-release assay,
respectively.
Results: Patients in early clinical stage of breast cancer had significantly decreased NK
cell cytotoxicity compared to controls. However, patients with advanced clinical stage
had significantly decreased NK cell cytotoxicity compared to early breast cancer
patients and controls. Positive correlation was shown between intracellular level of
IFNγ in PBL and NK cell activity in both healthy controls and all investigated patients.
However, in patients with advanced disease stages positive correlation between
intracellular IFNγ level in PBL and NK cell activity was found, while there was no
correlation between the IFNγ level in PBL and NK cell activity in patients in early
disease stage. IL-2 increased NK cell cytotoxicity in breast cancer patients and control.
Furthermore, IFNα showed this effect also in patients and controls.
Conclusions: In this study we show that, in breast cancer patients, lower IFNγ level and
reduced NK cell cytotoxicity, important in the control of tumor growth, are associated
with tumor progression. These results indicate that IFNγ level and NK cell cytotoxicity
may represent possible targets in designing new therapeutic agents in this disease.
Legal entity responsible for the study: National Projects funded by Ministry of
Science Government of Serbia
Funding: Ministry of Science
Disclosure: All authors have declared no conflicts of interest.
38P
Annals of Oncology
Antitumor immunity against hCGb induced by a tumor cell
vaccine modified with a fusion gene of hCGb and polyarginines
Y. Zhang 1 ,C.Su 2 , Y-S. Wang 1 ,Y.Lu 1 , Y-Q. Wei 1
1 Thoracic Oncology, Cancer Center and State Key Laboratory of Biotherapy, West
China Hospital, West China Medical School, Sichuan University, Chengdu, China,
2 State Key Laboratory of Biotherapy, West China Hospital, Sichuan University,
Chengdu, China
Background: Human chorionic gonadotropin β (hCGβ) is a kind of pregnancy
hormones, moreover, it is a tumor-associated antigen ectopically expressed on a variety
of human non-trophoblastic tumors such as pancreatic cancer, bladder cancer and
lung cancer. Therefore, hCGβ is considered as an ideal target antigen. However, as a
self-antigen, hCGβ is tolerated by the immune system and immune response is hardly
induced. 9-mer of L-arginine (Arg9), a type of cell penetrating peptide, can play an
important role in the translocation process.
Methods: Firstly, we designed and constructed two eukaryotic expressing plasmids
including pCDNA3.1-hCGβ-Arg9 (phCGβ-Arg9) and pCDNA3.1-hCGβ (phCGβ).
Secondly, B16.E5, a B16 cell line expressing hCGβ, was acquired by transfected
B16-F10 cells with phCGβ and selected with G418. Meanwhile we constructed
hCGβ-Arg9 gene modified tumor cell vaccine by transient transfection of phCGβ-Arg9
into B16-F10 cells with liposome. Finally, we took the prophylactic vaccination
experiment in vivo to investigate the protective efficacy and the immune mechanisms.
Results: The transfectant with highest expression of hCGβ was screened and named
B16.E5 as a tumor model in this experiment. The results of protective experiment
demonstrated 60% mice of hCGβ-Arg9 group were protected from the challenge of B16.
E5 cells. Moreover, survival benefit was also observed in mice vaccinated with the
hCGβ-Arg9 tumor vaccine (48.4 ± 4.9 days) compared with controls. Then, the
experiments for immune mechanism were conducted, including T lymphocytes adoptive
transfer experiment, CTL-mediated cytotoxicity analysis, hCGβ antibody tests of serum
after vaccination and serum transfer analysis. All of these suggested cellular immunity,
rather than humoral immunity, may play the major role in the antitumor activity.
Conclusions: We designed and constructed the tumor cell vaccine modified with
hCGβ-Arg9 gene and demonstrated that this vaccine can induce cellular immunity,
through which the vaccine can play protective efficacy in animal experiments. Our
work may contribute to designing novel generation of tumor vaccines.
Legal entity responsible for the study: Department of Thoracic Oncology, Cancer
Center, State Key Laboratory of Biotherapy, West China Hospital, West China Medical
School, Sichuan University, Chengdu, Sichuan, China
Funding: National Natural Science Funds of China (81402561)
Disclosure: All authors have declared no conflicts of interest.
vi10 | abstracts Volume 27 | Supplement 6 | October 2016