212P - Claudin-2: a new regulator of cancer stem cell self-renewal in colorectal cancer

Date 17 December 2016
Event ESMO Asia 2016 Congress
Session Poster lunch
Topics Colon and Rectal Cancer
Rectal Cancer
Translational Research
Presenter Sophie Paquet-Fifield
Citation Annals of Oncology (2016) 27 (suppl_9): ix53-ix67. 10.1093/annonc/mdw581
Authors S. Paquet-Fifield1, S.L. Koh2, L. Cheng3, L.M. Failla2, F. Hollande2
  • 1Pathology, The University of Melbourne, 3010 - Melbourne/AU
  • 2Pathology, The University of Melburne, 3010 - Melbourne/AU
  • 3Department Of Biochemistry And Genetics, La Trobe Institute for Molecular Science, 3083 - Melbourne/AU

Abstract

Background

Colorectal cancer (CRC) represents the third most lethal cancer worldwide. Fatal outcome often results from a recurrence of metastatic tumours, and a subpopulation of cancer cells called Cancer Stem Cells (CSCs) is thought to be instrumental for this process. Although the overexpression of the tight junction protein claudin-2 correlates with cancer progression in human CRC, and its expression in vitro enhances cell proliferation and colony formation and reduces chemosensitivity of CRC cells, the role of claudin-2 in regulating colorectal CSCs remains unknown.

Methods

We experimentally overexpressed or down-regulated claudin-2 expression in unique patient-derived cells from primary colorectal tumours and liver metastases, as well as in several classical CRC cell lines, depending on their endogenous level of claudin-2 expression. We performed stem cell assays in vitro (Extreme Limiting Dilution Assay, colonosphere formation assays) and xenograft experiments in vivo to demonstrate that claudin-2 promotes self-renewal of CSCs. We also performed qRT-PCR analysis of stage II/III CRC tumours post-5-FU-based adjuvant chemotherapy, combined with data mining of two large genomic datasets of equivalent samples. Next Generation Sequencing was performed to further analyse miRNAs expression and pathways were analysed.

Results

Claudin-2 expression correlates with higher probability of recurrence and poor prognosis in the clinic. Based on the quantification of stem cell activity (ALDH activity), we further show that claudin-2 regulates phenotypic transitions between CSCs and non-CSCs phenotypes. Finally, Next Generation Sequencing analyses comparing levels of miRNAs between the SC-like population expressing or not claudin-2, identified a list of 9 miRNAs directly involved in Wnt/beta-catenin, Stem Cell and Colorectal cancer signalling pathways. Further insights into the molecular regulation of CSCs in CRC by claudin-2 be discussed.

Conclusions

Our findings demonstrate for the first time that claudin-2 regulates the self-renewal tumour-initiating ability of colorectal CSCs. These new molecular insights are novel and important to lead the development of future therapeutic strategies targeting CSCs against post-treatment recurrence.

Clinical trial indentification

Legal entity responsible for the study

University of Melbourne

Funding

University of Melbourne

Disclosure

S. Paquet-Fifield: The presenter and all co-authors do not identify any financial interest in products or processes involved in their research. S.L. Koh: no financial interest. All other authors have declared no conflicts of interest.