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
3047 - Health-related quality of life in Greek haematogical malignancies patients undergoing chemotherapy
Presenter: Maria Lavdaniti
Session: Poster Display session 3
Resources:
Abstract
1121 - Experiences of endocrine therapy after breast cancer surgery
Presenter: Susanne Ahlstedt Karlsson
Session: Poster Display session 3
Resources:
Abstract
2305 - The effects of progressive muscle relaxation and mindfulness meditation on fatigue, coping styles, and quality of life in breast cancer patients receiving adjuvant paclitaxel regimen: An-assessor blinded, three-arm randomized controlled trial
Presenter: Zehra Gok Metin
Session: Poster Display session 3
Resources:
Abstract
4561 - Agreement between breast cancer patients and oncologists on the severity of patients’ symptoms and functions during a one-year follow-up after treatment.
Presenter: Randi Reidunsdatter
Session: Poster Display session 3
Resources:
Abstract
1768 - Taste Changes and Associated Factors in Patients Receiving Chemotherapy
Presenter: Gulcan Bagcivan
Session: Poster Display session 3
Resources:
Abstract
1830 - CART-19: a comparative between literature versus experience
Presenter: Cassandra Andersson Vila
Session: Poster Display session 3
Resources:
Abstract
4027 - Unplanned emergency department use by people receiving ambulatory anti-cancer agents with potential febrile neutropenia
Presenter: Meritxell Casanovas-Blanco
Session: Poster Display session 3
Resources:
Abstract
4754 - Examining the benefits of medical exercise during radiotherapy in patients after mastectomy
Presenter: Nikolina Dodlek
Session: Poster Display session 3
Resources:
Abstract
2510 - Assessment Quality of Life with Hand-Foot Syndrome Induced by Apatinib Combined with Anti-PD-1 Therapy in NSCLC
Presenter: Qi Jiang
Session: Poster Display session 3
Resources:
Abstract
2989 - Adverse effects of chemotherapy influence the patients’ quality of life : Analysis of implicated factors
Presenter: Maria Lavdaniti
Session: Poster Display session 3
Resources:
Abstract