Editorial comment

Non peer reviewedSubmitted Versio

Developmental signals in skin morphogenesis

Non peer reviewedFinal Accepted Versio

Transient activaton of β-catenin signalling in adult mouse epidermis is sufficient to induce new hair follicles but continuous activation is required to maintain hair follicle tumours

When β-catenin signalling is disturbed from mid-gestation onwards lineage commitment is profoundly altered in postnatal mouse epidermis. We have investigated whether adult epidermis has the capacity for β-catenin-induced lineage conversion without prior embryonic priming. We fused N-terminally truncated, stabilised β-catenin to the ligand-binding domain of a mutant oestrogen receptor (ΔNβ -cateninER). ΔNβ-cateninER was expressed in the epidermis of transgenic mice under the control of the keratin 14 promoter and β -catenin activity was induced in adult epidermis by topical application of 4-hydroxytamoxifen (4OHT). Within 7 days of daily 4OHT treatment resting hair follicles were recruited into the hair growth cycle and epithelial outgrowths formed from existing hair follicles and from interfollicular epidermis. The outgrowths expressed Sonic hedgehog, Patched and markers of hair follicle differentiation, indicative of de novo follicle formation. The interfollicular epidermal differentiation program was largely unaffected but after an initial wave of sebaceous gland duplication sebocyte differentiation was inhibited. A single application of 4OHT was as effective as repeated doses in inducing new follicles and growth of existing follicles. Treatment of epidermis with 4OHT for 21 days resulted in conversion of hair follicles to benign tumours resembling trichofolliculomas. The tumours were dependent on continuous activation of β-catenin and by 28 days after removal of the drug they had largely regressed. We conclude that interfollicular epidermis and sebaceous glands retain the ability to be reprogrammed in adult life and that continuous β-catenin signalling is required to maintain hair follicle tumours.Peer reviewedFinal Published versio

Inhibition of androgen-independent prostate cancer cell growth is enhanced by combination therapy targeting Hedgehog and ErbB signalling

<p>Abstract</p> <p>Background</p> <p>Prostate cancer is a leading cause of male cancer specific mortality. When cure by radical prostatectomy is not possible the next line of prostate cancer treatment is androgen deprivation. However prolonged androgen deprivation often results in relapse and androgen-independent prostate cancer that is inevitably fatal despite optimal chemotherapy. The Hedgehog signalling pathway has recently been implicated in prostate cancer development and metastasis. EGFR or ErbB2 expression has been also correlated with androgen independence, shorter survival and metastasis.</p> <p>Results</p> <p>We determined that the Hedgehog and ErbB signalling pathways are active in circulating tumour cells isolated from androgen-independent prostate cancer patients and in the androgen-independent prostate cancer cell line LNCaP C4-2B. As a basis for synergistic chemotherapy protocols combinations of the Hedgehog specific inhibitor cyclopamine and the ErbB signalling inhibitors gefitinib or lapatinib were tested in this study. Androgen-independent prostate cancer cell growth was inhibited by a SMO inhibitor (cyclopamine) which blocks Hedgehog signalling and by ErbB inhibitors (gefitinib and lapatinib). The isobologram and combination index method of Chou and Talalay was used to evaluate drug interactions. Synergistic antiproliferation effects were observed when the Hedgehog and ErbB inhibitors were combined.</p> <p>Conclusion</p> <p>Androgen-independent prostate cancer cell proliferation was associated with activity of the Hedgehog and ErbB signalling pathways. Cyclopamine, gefitinib or lapatinib treatment significantly decreased the proliferation of androgen-independent prostate cancer cells. The Hedgehog pathway therefore represents a promising new therapeutic target in androgen-independent prostate cancer. Synergistic effects were observed when Hedgehog and ErbB inhibitors were used together. This study may have clinical implications for improving the treatment of advanced prostate cancer.</p

Human papillomavirus is detected in transitional cell carcinoma arising in renal transplant recipients

"This is a non-final version of an article published in final form in Pathology The Journal of the Royal College of Pathologists of Australasia 41 (3) pp.245-247"Aims: We investigated the role of human papillomavirus HPV in the development of transitional cell carcinoma TCC arising in renal transplant recipients. Methods: Genomic DNA was extracted from 10 m paraffin embedded sections of five TCCs arising in five renal transplant recipients using the QIAamp DNA mini kit according to the manufacturer's instructions. β-globin PCR was performed to test DNA adequacy. Samples were tested for the presence of HPV DNA by broad spectrum HPV PCR method using non-biotinylated SPF10 primers SPF1A, SPF1B, SPF1C, SPF1D, SPF2B, SPF2D which amplify a short 65 bp fragment. Positive bands were identified on a 3 gel. Positive samples underwent a second HPV PCR and were amplified using biotinylated SPF10 primer set, which amplifies the same 65 bp region of the L1 open reading frame. INNO-LiPA line probe assay was then performed to genotype the samples which uses a reverse hybridisation principle. Results: Four of five TCCs examined were positive for HPV. The high risk HPV16 was detected in three cases whereas in the fourth case an unclassifiable HPV genotype was present. In all DNA samples, β-globin amplification was successful. Conclusions: Our results indicate that HPV and in particular HPV16 may play an aetiological role in the development of TCC in renal transplant patients.Peer reviewedSubmitted Versio

International study into the use of intermittent hormone therapy in the treatment of carcinoma of the prostate : A meta-analysis of 1446 patients

OBJECTIVE: To review pooled phase II data to identify features of different regimens of intermittent hormone therapy (IHT), developed to reduce the morbidity of treating metastatic prostate cancer, and which carries a theoretical advantage of delaying the onset of androgen-independent prostate cancer, (AIPC) that are associated with success, highlighting features which require exploration with prospective trials to establish the best strategies for using this treatment. METHODS: Individual data were collated on 1446 patients with adequate information, from 10 phase II studies with >50 cases, identified through Pubmed. RESULTS: Univariate and multivariate Cox proportional hazard models were developed to predict treatment success with a high degree of statistical success. The prostate-specific antigen (PSA) nadir, the PSA threshold to restart treatment, and medication type and duration, were important predictors of outcome. CONCLUSIONS: The duration of biochemical remission after a period of HT is a durable early indicator of how rapidly AIPC and death will occur, and will make a useful endpoint in future trials to investigate the best ways to use IHT based on the important treatment cycling variables described above. Patients spent a mean of 39% of the time off treatment. The initial PSA level and PSA nadir allow the identification of patients with prostate cancer in whom it might be possible to avoid radical therapy.Peer reviewe

Hedgehog Signalling in Androgen Independent Prostate Cancer

Objectives: Androgen-deprivation therapy effectively shrinks hormone-naïve prostate cancer, both in the prostate and at sites of distant metastasis. However prolonged androgen deprivation generally results in relapse and androgen-independent tumour growth, which is inevitably fatal. The molecular events that enable prostate cancer cells to proliferate in reduced androgen conditions are poorly understood. Here we investigate the role of Hedgehog signalling in androgen-independent prostate cancer (AIPC). Methods: Activity of the Hedgehog signalling pathway was analysed in cultured prostate cancer cells, and circulating prostate tumour cells were isolated from blood samples of patients with AIPC. Results: AIPC cells were derived through prolonged culture in reduced androgen conditions, modelling hormone therapy in patients, and expressed increased levels of Hedgehog signalling proteins. Exposure of cultured AIPC cells to cyclopamine, which inhibits Hedgehog signalling, resulted in inhibition of cancer cell growth. The expression of the Hedgehog receptor PTCH and the highly prostate cancer-specific gene DD3PCA3 was significantly higher in circulating prostate cancer cells isolated from patients with AIPC compared with samples prepared from normal individuals. There was an association between PTCH and DD3PCA3 expression and the length of androgen-ablation therapy. Conclusions: Our data are consistent with reports implicating overactivity of Hedgehog signalling in prostate cancer and suggest that Hedgehog signalling contributes to the androgen-independent growth of prostate cancer cells. As systemic anti-Hedgehog medicines are developed, the Hedgehog pathway will become a potential new therapeutic target in advanced prostate cancer.Peer reviewedFinal Accepted Versio

Exposing the human nude phenotype [4]

Peer reviewedSubmitted Versio

Detection of TMPRSS2 : ERG fusion gene in circulating prostate cancer cells

Creative Commons Attribution-NonCommercial-Share Alike 3.0 license (CC BY-NC SA)Aim: To investigate the existence of TMPRSS2:ERG fusion gene in circulating tumor cells (CTC) from prostate cancer patients and its potential in monitoring tumor metastasis. Methods: We analyzed the frequency of TMPRSS2: ERG and TMPRSS2:ETV1 transcripts in 27 prostate cancer biopsies from prostatectomies, and TMPRSS2:ERG transcripts in CTC isolated from 15 patients with advanced androgen independent disease using reverse transcription polymerase chain reaction (RT-PCR). Fluorescence in situ hybridization (FISH) was applied to analyze the genomic truncation of ERG, which is the result of TMPRSS2:ERG fusion in 10 of the 15 CTC samples. Results: TMPRSS2: ERG transcripts were found in 44% of our samples, but we did not detect expression of TMPRSS2:ETV1. Using FISH analysis we detected chromosomal rearrangements affecting the ERG gene in 6 of 10 CTC samples, including 1 case with associated TMPRSS2:ERG fusion at the primary site. However, TMPRSS2:ERG transcripts were not detected in any of the 15 CTC samples, including the 10 cases analyzed by FISH. Conclusion: Although further study is required to address the association between TMPRSS2:ERG fusion and prostate cancer metastasis, detection of genomic truncation of the ERG gene by FISH analysis could be useful for monitoring the appearance of CTC and the potential for prostate cancer metastasis.Peer reviewedFinal Published versio

Energy input is primary controller of methane bubbling in subarctic lakes

Emission of methane (CH4) from surface waters is often dominated by ebullition (bubbling), a transport mode with high‐spatiotemporal variability. Based on new and extensive CH4 ebullition data, we demonstrate striking correlations (r2 between 0.92 and 0.997) when comparing seasonal bubble CH4 flux from three shallow subarctic lakes to four readily measurable proxies of incoming energy flux and daily flux magnitudes to surface sediment temperature (r2 between 0.86 and 0.94). Our results after continuous multiyear sampling suggest that CH4 ebullition is a predictable process, and that heat flux into the lakes is the dominant driver of gas production and release. Future changes in the energy received by lakes and ponds due to shorter ice‐covered seasons will predictably alter the ebullitive CH4 flux from freshwater systems across northern landscapes. This finding is critical for our understanding of the dynamics of radiatively important trace gas sources and associated climate feedback