Oral Presentation The Annual Scientific Meeting of the Endocrine Society of Australia and the Society for Reproductive Biology 2014

TGFβ, RA, WNT and Hedgehog signalling pathways: potential for crosstalk in driving testicular germ cell tumour cell fate decisions (#153)

Julia C Young 1 , Genevieve E Kerr 1 , Diana Micati 1 , Penelope Whiley 1 , Ewa Rajpert-deMeyts 2 , Helen E Abud 1 , Kate L Loveland 1
  1. Monash University, Clayton, VIC, Australia
  2. Life and Growth, University of Copenhagen, Copenhagen, Denmark

The human testicular germ cell cancer, seminoma, is one of the most common cancers of young men, and increasing in prevalence globally.  To better understand mechanisms that govern viability, proliferation, and migration in testicular cancers, we used the TCam-2 seminoma cell line to model seminoma responses to four major signalling pathways: TGFb, retinoic acid (RA), Hedgehog, and WNT. Transcript, immunohistochemical, and functional analyses show TCam-2 cells are responsive to activation/suppression of all four pathways, and highlighted potential crosstalk points in these cells. Activation of TGFb signalling by BMP4 supports TCam-2 viability in the absence of serum, and suppression of canonical WNT signalling at the intracellular level with either IWR-1 or CCT036477 leads to loss of viability (measured by propidium iodide incorporation) and decreased migration (wound healing assay). These pathways exhibit crosstalk in embryonic stem cells to reduce pluripotency network transcripts, and may also intersect to drive alterations to the TCam-2 seminoma cell differentiation status. Activin treatment leads to a significant increase in KIT transcript levels (measured by Q-RTPCR), and both activin and WNT3a treatments decrease AP2g transcript levels, together indicative of increased differentiation. WNT3a treatment additionally induces a significant decrease in OCT3/4 and BLIMP1 levels, strengthening the argument that this pathway may influence differentiation status in seminoma. Retinoic acid, a factor often associated with differentiation, also induces an increase in KIT transcript levels, which is potentially mediated in part by induction of increased SMAD3 (TGFb mediator) nuclear localization, measured by immunofluorescence and confocal image analysis.  We also show by Q-RTPCR that activin treatment decreases GLI1 transcript levels in seminoma samples, suggesting possible involvement of Hedgehog signalling in differentiation status.  These data demonstrate the potential for pathway crosstalk intersection points that may serve as targets for therapeutic interventions which can be tested using our established primary culture system [1].