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Open Access Research

TMEM16A alternative splicing coordination in breast cancer

Ifeoma Ubby14, Erica Bussani1, Antonio Colonna2, Giuseppe Stacul2, Martina Locatelli2, Paolo Scudieri3, Luis Galietta3 and Franco Pagani1*

Author Affiliations

1 Human Molecular Genetics, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy

2 Gorizia Hospital, Presidio Ospedaliero di Gorizia, Gorizia, Italy

3 U.O.C. Genetica Medica, Istituto Giannina Gaslini, Genova, Italy

4 Present address: NCCS, National Cancer Centre Singapore, Singapore, Singapore

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Molecular Cancer 2013, 12:75  doi:10.1186/1476-4598-12-75

Published: 16 July 2013

Abstract

Background

TMEM16A, also known as Anoctamin-1, is a calcium-activated chloride channel gene overexpressed in many tumors. The role of TMEM16A in cancer is not completely understood and no data are available regarding the potential tumorigenic properties of the multiple isoforms generated by alternative splicing (AS).

Methods

We evaluated TMEM16A AS pattern, isoforms distribution and Splicing Coordination (SC), in normal tissues and breast cancers, through a semi-quantitative PCR-assay that amplifies transcripts across three AS exons, 6b, 13 and 15.

Results

In breast cancer, we did not observe an association either to AS of individual exons or to specific TMEM16A isoforms, and induced expression of the most common isoforms present in tumors in the HEK293 Flp-In Tet-ON system had no effect on cellular proliferation and migration. The analysis of splicing coordination, a mechanism that regulates AS of distant exons, showed a preferential association of exon 6b and 15 in several normal tissues and tumors: isoforms that predominantly include exon 6b tend to exclude exon 15 and vice versa. Interestingly, we found an increase in SC in breast tumors compared to matched normal tissues.

Conclusions

As the different TMEM16A isoforms do not affect proliferation or migration and do not associate with tumors, our results suggest that the resulting channel activities are not directly involved in cell growth and motility. Conversely, the observed increase in SC in breast tumors suggests that the maintenance of the regulatory mechanism that coordinates distant alternative spliced exons in multiple genes other than TMEM16A is necessary for cancer cell viability.

Keywords:
TMEM16A isoforms; Alternative splicing; Splicing coordination; Breast cancer