PIK3CA copy number aberration and activation of the PI3K-AKT-mTOR pathway in varied disease states of penile cancer

PLOS ONE, Nov 2019

Background Therapeutic targeting of the PI3K-AKT-mTOR pathway may benefit patients with advanced penile squamous cell carcinoma (PSCC). Objectives To determine the prevalence of PIK3CA copy number gain and correlate this with the activity status of PI3K-AKT-mTOR pathway in pre-malignant penile intraepithelial neoplasia (PeIN) and invasive PSCC. Materials and methods Archival tissue blocks were obtained from 58 PeIN and 244 primary PSCC patients treated at St George’s Hospital. PIK3CA copy number status (CNS) was assessed by fluorescence in-situ hybridisation. High-risk HPV DNA was detected with INNO-LiPA assay. p16INK4A, p-AKT and p-mTOR protein expression were assessed using immunohistochemistry (IHC). Results Increased prevalence of PIK3CA copy number gain was seen in PSCC in comparison to PeIN (84/199 (42%) vs. 10/58 (17%); p = 0.0009). Analysis of the p-AKT and p-mTOR revealed a tendency to a more common expression of cytoplasmic p-AKT (p = 0.1318), nuclear p-AKT (p<0.0001) and cytoplasmic mTOR (p = 0.0006) in PeIN than PSCC. A significant association between p-AKT cytoplasmic immunoexpression and PIK3CA CNS (p = 0.0404) was found in PeIN. Conclusion Overall, PIK3CA copy number gain correlated with activation of the PI3K-AKT-mTOR pathway in PeIN and activation of this pathway is primarily involved in early penile carcinogenesis. Based on these results therapeutic targeting of this pathway in advanced PSCC is unlikely to produce significant clinical benefit. Future studies will need to focus on alternative therapeutic targets.

A PDF file should load here. If you do not see its contents the file may be temporarily unavailable at the journal website or you do not have a PDF plug-in installed and enabled in your browser.

Alternatively, you can download the file locally and open with any standalone PDF reader:

https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0198905&type=printable

PIK3CA copy number aberration and activation of the PI3K-AKT-mTOR pathway in varied disease states of penile cancer

June PIK3CA copy number aberration and activation of the PI3K-AKT-mTOR pathway in varied disease states of penile cancer Anthony Adimonye 0 1 Elzbieta Stankiewicz 0 1 Susannah La-Touche 0 1 Sakunthala Kudahetti 0 1 Giorgia Trevisan 0 Brendan Tinwell 0 Cathy Corbishley 0 Yong- Jie Lu 0 1 Nick Watkin 0 Daniel Berney 0 1 0 Editor: Aamir Ahmad, University of South Alabama Mitchell Cancer Institute , UNITED STATES 1 Barts Cancer Institute, Centre for Molecular Oncology, Barts and The London School of Medicine and Dentistry, Queen Mary University of London , London , United Kingdom , 2 Department of Histopathology, Royal London Hospital, Barts Health NHS Trust , London , United Kingdom , 3 Department of Cellular Pathology, St George's Hospital , London , United Kingdom , 4 Department of Urology, St George's Hospital , London , United Kingdom - Data Availability Statement: All relevant data are within the paper. Funding: This work was supported and funded by Orchid (www.orchid-cancer.org.uk) and Barts Charity to DB. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing interests: The authors have declared that no competing interests exist. Background Objectives and invasive PSCC. Materials and methods Archival tissue blocks were obtained from 58 PeIN and 244 primary PSCC patients treated at St George's Hospital. PIK3CA copy number status (CNS) was assessed by fluorescence in-situ hybridisation. High-risk HPV DNA was detected with INNO-LiPA assay. p16INK4A, pAKT and p-mTOR protein expression were assessed using immunohistochemistry (IHC). Results Increased prevalence of PIK3CA copy number gain was seen in PSCC in comparison to PeIN (84/199 (42%) vs. 10/58 (17%); p = 0.0009). Analysis of the p-AKT and p-mTOR revealed a tendency to a more common expression of cytoplasmic p-AKT (p = 0.1318), nuclear p-AKT (p<0.0001) and cytoplasmic mTOR (p = 0.0006) in PeIN than PSCC. A significant association between p-AKT cytoplasmic immunoexpression and PIK3CA CNS (p = 0.0404) was found in PeIN. Conclusion Overall, PIK3CA copy number gain correlated with activation of the PI3K-AKT-mTOR pathway in PeIN and activation of this pathway is primarily involved in early penile carcinogenesis. Based on these results therapeutic targeting of this pathway in advanced PSCC is unlikely to produce significant clinical benefit. Future studies will need to focus on alternative therapeutic targets. Introduction Penile squamous cell carcinoma (PSCC), though uncommon with an incidence of less 1 per 100,000 men in Europe and USA [ 1 ], poses significant physical and psychological stress to those afflicted [ 2 ]. Risk factors for PSCC include high-risk human papilloma virus (hr-HPV), phimosis, lichen sclerosis and smoking among others [ 1, 2 ]. A multitude of different histological subtypes of PSCC exist with distinct clinical and prognostic associations [3]. With PSCC two distinct patient groups exist, the first a large cohort with a high cure rate (80%) and excellent long-term survival in those with organ-confined disease with no or minimal regional lymph node involvement [ 2 ]. The second is a smaller patient cohort with highly aggressive disease with significant propensity to metastasise and poor prognosis [ 4 ]. Management of the latter group with aggressive and advanced tumours still remains difficult as most are chemo/ radio-resistant with limited treatment options available when first line options fails [ 5 ]. The key molecular alterations driving PSCC development and potential therapeutics targets are incompletely understood. The phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha (PIK3CA) gene is mutated and/or amplified/gained in numerous cancers, leading to dysregulation of the PI3K-AKT-mTOR pathway and resulting in increased cell proliferation, angiogenesis and survival [ 6 ]. Previous mutational analysis papers [ 7 ] and more recent next-generation sequencing studies in PSCC have confirmed the involvement of the altered PIK3CA oncogene in penile carcinogenesis [ 8, 9 ]. Few papers have looked into the activity status of this pathway in PSCC, one of which was Ferrandiz-Pulido et al. [ 10 ] whom in 67 PSCC cases found p-mTOR (activated mTOR) and pelF4E (a downstream effector protein of mTOR) immunoexpression was significantly increased in PSCC compared to adjacent normal tissues and associated with lymph node metastasis (p = 0.05 and p = 0.006, respectively). Raising the possibility of using already established biological therapies such as everolimus and temsirolimus (mTOR inhibitors), to target this pathway in PSCC [ 11 ]. Our objective was to determine the prevalence of PIK3CA copy number gain and correlate this with the activity status of PI3K-AKT-mTOR pathway in different disease states of penile cancer via utilisation of a large cohort of both pre-cancerous penile intraepithelial neoplasia (P (...truncated)


This is a preview of a remote PDF: https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0198905&type=printable

Anthony Adimonye, Elzbieta Stankiewicz, Susannah La-Touche, Sakunthala Kudahetti, Giorgia Trevisan, Brendan Tinwell, Cathy Corbishley, Yong-Jie Lu, Nick Watkin, Daniel Berney. PIK3CA copy number aberration and activation of the PI3K-AKT-mTOR pathway in varied disease states of penile cancer, PLOS ONE, 2018, Volume 13, Issue 6, DOI: 10.1371/journal.pone.0198905