Winter Meeting 2011 - The Pathological Society of Great Britain ...

Detailed Programme – Thursday 6 January 2011
Presenter = P · Abstract numbers are shown in bold and square brackets eg [S123]
Francis Crick Auditorium
15.00–17.30 PLENARY ORAL Presentations
Chair: Prof IO Ellis, University of Nottingham
Prof R Poulsom, Cancer Research UK – London Research Institute
15.00–15.15 [PL1] Mammary Gland Involution: Characterization of the Switch to Irreversibility
P K Hughes; CJ Watson
University of Cambridge, Cambridge, United Kingdom
STUDY PURPOSE: Mammary gland involution comprises the organ’s retrograde change to its pre-pregnant state
following weaning. Involution has an initial reversible phase characterized by epithelial apoptosis and the ability
to recommence lactation if the pups are returned to the dam. A subsequent transition to irreversibility heralds
further cell death, basement membrane degradation, stromal remodelling and the inability to lactate. Mice with
a mammary-specific deletion of the transcription factor Stat3 exhibit a pronounced delay in involution, and have
an extended period during which lactation may be restored. Comparison of these mice with controls offers the
opportunity to study factors controlling the switch to irreversible involution.
METHODS AND RESULTS: Utilizing microarray data and RT-PCR analysis of murine tissue at specific involution
time points, we have identified a panel of ‘switch marker genes’. Of particular interest is CXCL14, a chemokine
which is involved in macrophage recruitment and fibroblast stimulation. We demonstrate that CXCL14 exhibits
a pronounced increase in expression at the switch in control animals. In the Stat3 reversible model CXCL14
expression is lower, and reduces as involution progresses. In vitro, mammary epithelial EpH4 cells exhibit a marked
increase in CXCL14 expression following oncostatin M (OSM) stimulation. OSM is a potent stimulator of Stat3
activity in the second phase of involution. In vivo, a large influx of macrophages can be seen in control glands at 96
hours of involution, with reduced numbers observed in Stat3 knockout glands.
CONCLUSIONS: Our data suggests that the chemokine CXCL14 is a robust marker of the switch to irreversible
involution, and may be a direct target of Stat3. The role of CXCL14 in the switch to irreversible involution merits
further investigation, particularly given its poorly defined role in breast tumour biology.
15.15–15.30 [PL2] The Tumour Suppressor ARF Can Promote Invasion in a p53 Null Setting
P B Doyle 1 ; EH Tan 2 ; P Timpson 2 ; LM Machesky 2 ; RA Ridgway 2 ; RE Jeffery 3 ;
R Poulsom 3 ; JP Morton 2 ; OJ Sansom 2
St. James’s Hospital, Dublin, Ireland; 2 Beatson Institute for Cancer Research, Glasgow, United Kingdom;
Histopathology Lab, Cancer Research UK – London Research Institute, London, United Kingdom
We have previously shown that a combination of APC and p53 mutation results in a dramatic increase in invasion,
compared to APC mutation alone in a mouse model of intestinal carcinoma. This model closely mimics the human
disease, including the potential to metastasise. We now go on to investigate the mechanism of this increased
invasion. In doing this we have examined the β-catenin paradox and studied a potentially novel pro-invasive role
for ARF.
In the invasive carcinomas that developed in the p53 mutant mice we could detect nuclear β-catenin throughout
the tumours, however there was a massive increase at the invasive front. This increase in nuclear β-catenin was
associated with an increase in Wnt target genes, including Myc, Sox-9, Lgr5 and the pro-invasive actin regulator
Fascin. As Myc is known to induce ARF expression we examined levels of this protein and found that it is indeed
upregulated, specifically at the invasive front. This increase in ARF expression was specific to tumours in which
p53 function was lost. In the few tumours with wild-type p53 that did show invasion no increase in ARF was seen
at the invasive front.
In order to assess if this increase in ARF was functional, rather than merely marking aberrant Myc levels, we
overexpressed ARF in p53 null HCT-116 colorectal cancer cells. We showed that overexpression of ARF resulted
in a survival advantage for p53 null cells and moreover cells overexpressing ARF showed an increase in invasive
behaviour in both in-vitro and in-vivo assays.
In this study we have shown two levels of β-catenin activation in invasive tumours, with higher levels of expression
seen at the invasive front of the tumours. We have also shown that ARF levels are increased at the invasive front.
Although ARF is generally thought of a tumour suppressor, we have shown a pro-invasive role for ARF in the
setting of p53 loss.
15.30–15.45 [PL3] A Kras-Cten-FAK Axis Promotes Cell Motility in Pancreatic Cancer
P S Al-Ghamdi; J Cachat; M Ahmed; D Jackson; K Kindle; M Ilyas
Nottingham University, Nottingham, United Kingdom
Cten is a protein located at focal adhesions and involved in cell motility. The role of Cten in neoplasia is context
dependent – while it acts as a tumour suppressor in prostate cancer, it acts as an oncogene in colon, breast, lung
and gastric cancer. In this study we evaluated the role of Cten in the pancreas by a dual approach of knockdown in
high expressing cell lines and ectopic expression in low Cten level cells. Firstly, Cten was knocked down in PSN-1
and ectopic expressed in Panc-1 and this was associated with inhibition and promotion of cell migration (p