Journal Thoracic Oncology

Abstracts Journal of Thoracic Oncology • Volume 12 Issue S1 January 2017
POSTER SESSION 1 - P1.07: SCLC/NEUROENDOCRINE TUMORS
MOLECULAR CHANGES –
MONDAY, DECEMBER 5, 2016
P1.07-029 IN VITRO EFFECTS OF PEGYLATED ARGINASE IN SMALL
CELL LUNG CANCER
Shi Xu 1 , Sze Kwan Lam 1 , Paul Ning Man Cheng 2 , James Chung Man Ho 1
1 The University of Hong Kong, Hong Kong/Hong Kong Prc, 2 Bio-Cancer Treatment
International Limited, Hong Kong/Hong Kong Prc
Background: Small cell lung cancer (SCLC) accounts for 15% of all lung cancer
cases. SCLC is notoriously difficult to treat with high relapse rate and the
current standard treatment remains chemotherapy. Arginine is an important
amino acid in normal human cells that can be replenished through urea cycle,
but some tumors are arginine-auxotrophic due to deficient argininosuccinate
synthetase (ASS1) and/or ornithine transcarbamylase (OTC). BCT-100 is a
pegylated arginase, which converts arginine to citrulline, has demonstrated
anticancer activity in human melanoma, hepatocellular carcinoma and acute
myeloid leukemia. We aim to determine the in vitro effects of BCT-100 in SCLC.
Methods: A panel of 7 SCLC cell lines was obtained from ATCC. Cell viability
was detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium
bromide (MTT) assay and protein expression by Western blot. Knockdown
of OTC was performed using siRNA. Flow cytometry was applied to detect
mitochondrial membrane depolarization (MMD). Results: The IC 50
values
of BCT-100 in H69, DMS79, H187, H209, H526, H841 and SW1271 cells were
462.9±112.2, >1000, 24.9±6.4, 8.6±0.8, 10.1±0.7, >1000 and 49.2±7.4 mU/mL
respectively. Overexpression of ASS1 in H69 and DMS79 cells, and OTC in
H841 cells were associated with resistance to BCT-100. Knocking down of OTC
increased sensitivity of BCT-100 in H841 cells partially via apoptosis. H526 cells
(BCT-100-sensitive) was selected for mechanistic study. MMD was observed
in BCT-100 treatment accompanied by cytochrome c and SMAC release from
mitochondria to cytosol. N-acetylcysteine (NAC) could significantly reverse
apoptosis induced by BCT-100. Besides, cyclin A2, cyclin B1 and CDK7 were
downregulated in a time-dependent manner. The protein expression of p-AKT
and p-mTOR was increased after exposure while RAS/RAF/ERK cell signaling
pathway was inhibited with BCT-100 treatment. Conclusion: SCLC cell lines
with low ASS1 and OTC expression were sensitive to arginine depletion with
BCT-100, mediated through oxidative stress, cell cycle arrest and apoptotic
pathway.
Keywords: small cell lung cancer, apoptosis, Pegylated arginase BCT-100,
oxidative stress
POSTER SESSION 1 - P1.07: SCLC/NEUROENDOCRINE TUMORS
MOLECULAR CHANGES –
MONDAY, DECEMBER 5, 2016
P1.07-030 GENE SIGNATURE OF EMT IN NEUROENDOCRINE LUNG
CARCINOMA: A COMPARATIVE ANALYSIS WITH ADENOCARCINOMA
AND SQUAMOUS CELL CARCINOMA
Tabatha Prieto 1 , Vanessa De Sá 2 , Eloisa Olivieri 2 , Eduardo Da Silva 3 , Rui Reis 3 ,
Dirce Carraro 2 , Vera Capelozzi 1
1 Pathology, Faculdade de Medicina Da Usp, São Paulo/Brazil, 2 Pathology, Ac
Camargo Cancer Center, São Paulo/Brazil, 3 Molecular Oncology Research, Barretos
Cancer Hospital, Barretos/Brazil
Background: Recurrence and metastasis are responsible for 90% of the
death of patients with lung cancer. Adenocarcinomas (ADc) primarily invade
blood vessels with distant metastasis, whereas squamous cell carcinoma
(SqCC) involves the mediastinal lymph nodes. Neuroendocrine carcinomas
of low-grade (typical and atypical carcinoid) are indolent, while high-grade
NE carcinoma (large cell NE and small cell carcinomas) metastasize rapidly.
Biomarkers of invasiveness in lung carcinomas still cannot be definitely
determined. Epithelial to mesenchymal transition (EMT) genes profile emerge
promise as indicator of invasion and metastasis. Our aim was to compare EMT
gene expression in NELC, ADc and SqCC and its impact on behavior of these
tumors. Methods: EMT gene expression was quantified with a quantitative
real-time (RT)- PCR carried out on StepOnePlus Real-Time PCR System
(Applied Biosystems) with RT2 Profiler PCR Array System for EMT (Qiagen,
Dusseldorf, Germany). Results: Younger patients expressed higher amount of
AHNAK, IL1RN, MSN, TCF3 and VIM than older (p