Abstract 1782
Background
EpCAM is a type I transmembrane glycoprotein with an extracellular domain (EpEX) and an intracellular domain (EpICD), which have 265 and 26 amino acid residues, respectively. EpCAM is highly expressed in advanced epithelial cancers and tumor-initiating cells, but its role in cancer progression remains to be elucidated.
Methods
To identify cell signaling pathways that are stimulated by EpEX, we used a Human Phospho-RTK Array Kit to screen for phosphorylation of RTKs. Inhibition of EpEX-induced EGFR-PI3K-AKT signaling was analyzed by small molecule inhibitors or shRNA knockdown.
Results
Here, we found that EpEX activated AKT signaling, thereby inducing the phosphorylation and nuclear exclusion of FOXO3a. The EGFR inhibitor, AG1478, and MEK inhibitor, U0126, both decreased the production of EpICD, which was found to be necessary for nuclear accumulation of β-catenin protein and expression of HIF1α target genes in vitro and in mouse xenograft models. We also demonstrated that treatment with an anti-EpCAM neutralizing antibody, EpAb2-6, decreased the ADAM17 and γ-secretase activity, the EpCAM-downstream gene expression, and tumor colony and sphere formation. We also found that EpAb2-6 inhibited EpEX-activated EGFR-PI3K-AKT signaling and induced apoptotic signaling through FOXO3a activation of HTRA2 gene expression. Importantly, we also showed that EpAb2-6 inhibited the nuclear translocation of EpICD and oncogenic signaling through β-catenin. Finally, in both metastatic and orthotopic animal models of colorectal cancer, EpAb2-6 therapy exhibited an antitumor effect and markedly extended the survival time of mice.
Conclusions
Our results demonstrate that EpEX contributes to malignancy by functioning as a growth factor, which activates EpICD-mediated signaling, thereby enhancing colon cancer cell survival. To the best of our knowledge, hEpAb2-6 is the first humanized anti-EpCAM antibody to directly trigger apoptosis in cancer cells. Thus, we provide novel insight into EpEX-EGFR signaling, which can be considered as a promising target for treatment of colon cancer.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Academia Sinica.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
3117 - A modified Edmonton Symptom Assessment Scale for assessing symptoms in one day chemotherapy clinic
Presenter: Anjuleta Kampitsi
Session: Poster Display session 3
Resources:
Abstract
6058 - Level of physical activity and nutritional status in cancer patients with fatigue: an exploratory cross-sectional study
Presenter: Patrick Jahn
Session: Poster Display session 3
Resources:
Abstract
1980 - Catheter related necrotizing fascitiis in haematological patients. Case report and implications for nursing
Presenter: Arianna Rosich Soteras
Session: Poster Display session 3
Resources:
Abstract
3984 - Everyday life with Long-term Chemotherapy Induced Peripheral Neuropathy among Patient in Adjuvant Treatment for Colorectal Cancer – a Multi Methods Study
Presenter: Marlene Jensen
Session: Poster Display session 3
Resources:
Abstract
2202 - Scalp cooler is effective in reducing chemotherapy-induced alopecia among breast cancer patients : a single institution experience
Presenter: Emilia Gianotti
Session: Poster Display session 3
Resources:
Abstract
5942 - Nursing management of fatigue in cancer patients: mixed methods study
Presenter: Angela Tolotti
Session: Poster Display session 3
Resources:
Abstract
2930 - Awareness of Nursing Students about the Warning Signs of Cancer
Presenter: Hatice Yakar
Session: Poster Display session 3
Resources:
Abstract
2978 - Assessment of quality of life in patients with cancer and diabetes 2 in Northern Greece.
Presenter: STYLIANI MICHALOPOULOU
Session: Poster Display session 3
Resources:
Abstract
3400 - Radiation dose variables related to the causes of skin toxicities in women with breast cancer: a study proposal
Presenter: EULALIA PUJOL
Session: Poster Display session 3
Resources:
Abstract
2156 - How should the symptoms be managed after breast cancer surgery? An example of mobile app
Presenter: AYDANUR AYDIN
Session: Poster Display session 3
Resources:
Abstract