Despite remarkable advances in our understanding of the drivers of human malignancies, new targeted therapies often fail to show sufficient efficacy in clinical trials. Indeed, the cost of bringing a new agent to market has risen substantially in the last several decades, in part fuelled by extensive reliance on preclinical models that fail to accurately reflect tumour heterogeneity. To halt unsustainable rates of attrition in the drug discovery process, we must develop a new generation of preclinical models capable of reflecting the heterogeneity of varying degrees of complexity found in human cancers. Patient-derived tumour xenograft (PDTX) models prevail as arguably the most powerful in this regard because they capture cancer’s heterogeneous nature. Herein, we review current breast cancer models and their use in the drug discovery process, before discussing best practices for developing a highly annotated cohort of PDTX models. We describe the importance of extensive multidimensional molecular and functional characterisation of models and combination drug–drug screens to identify complex biomarkers of drug resistance and response. We reflect on our own experiences and propose the use of a cost-effective intermediate pharmacogenomic platform (the PDTX-PDTC platform) for breast cancer drug and biomarker discovery. We discuss the limitations and unanswered questions of PDTX models; yet, still strongly envision that their use in basic and translational research will dramatically change our understanding of breast cancer biology and how to more effectively treat it.
John W Cassidy, Ankita S Batra, Wendy Greenwood, and Alejandra Bruna
Ju-Yeon Moon, Man Ho Choi, and Jayoung Kim
Cholesterol and sex steroid hormones including androgens and estrogens play a critical role in the development and progression of urological diseases such as prostate cancer. This disease remains the most commonly diagnosed malignant tumor in men and is the leading cause of death from different cancers. Attempts to understand the role of cholesterol and steroid metabolism in urological diseases have been ongoing for many years, but despite this, our mechanistic and translational understanding remains elusive. In order to further evaluate the problem, we have taken an interest in metabolomics; a discipline dedicated to the systematic study of biologically active metabolites in cells, tissues, hair and biofluids. Recently, we provided evidence that a quantitative measurement of cholesterol and sex steroid metabolites can be successfully achieved using hair of human and mouse models. The overall goal of this short review article is to introduce current metabolomic technologies for the quantitative biomarker assay development and also to provide new insight into understanding the underlying mechanisms that trigger the pathological condition. Furthermore, this review will place a particular emphasis on how to prepare biospecimens (e.g., hair fiber), quantify molecular profiles and assess their clinical significance in various urological diseases.
Sakine Sever, Donna L White, and José M Garcia
Ghrelin is a hormone with multiple physiologic functions, including promotion of growth hormone release, stimulation of appetite and regulation of energy homeostasis. Treatment with ghrelin/ghrelin-receptor agonists is a prospective therapy for disease-related cachexia and malnutrition. In vitro studies have shown high expression of ghrelin in cancer tissue, although its role including its impact in cancer risk and progression has not been established. We performed a systematic literature review to identify peer-reviewed human or animal in vivo original research studies of ghrelin, ghrelin-receptor agonists, or ghrelin genetic variants and the risk, presence, or growth of cancer using structured searches in PubMed database as well as secondary searches of article reference lists, additional reviews and meta-analyses. Overall, 45 (73.8%) of the 61 studies reviewed, including all 11 involving exogenous ghrelin/ghrelin-receptor agonist treatment, reported either a null (no statistically significant difference) or inverse association of ghrelin/ghrelin-receptor agonists or ghrelin genetic variants with cancer risk, presence or growth; 10 (16.7%) studies reported positive associations; and 6 (10.0%) reported both negative or null and positive associations. Differences in serum ghrelin levels in cancer cases vs controls (typically lower) were reported for some but not all cancers. The majority of in vivo studies showed a null or inverse association of ghrelin with risk and progression of most cancers, suggesting that ghrelin/ghrelin-receptor agonist treatment may have a favorable safety profile to use for cancer cachexia. Additional large-scale prospective clinical trials as well as basic bioscientific research are warranted to further evaluate the safety and benefits of ghrelin treatment in patients with cancer.
Hyun Ho Han, Baek Gil Kim, Joo Hyun Lee, Suki Kang, Ji Eun Kim, and Nam Hoon Cho
In estrogen receptor-positive (ER+) breast cancer, it is recognized that metastases may develop after a long period of dormancy. Bone marrow (BM) vascular niche is where the dormant tumor cells are most likely to reside. So far, it is not fully understood why the dormant tumor cells become proliferative and eventually generate tumor. We hypothesized that therapeutic or menopause-related estrogen depletion may be the switch behind dormant ER+ tumor cell awakening in BM. We utilized an existing experimental model of BM endothelial niche that can simulate ER+ tumor cell dormancy to test our hypothesis. In results, estrogen depletion paradoxically promoted ER+ tumor cell proliferation in the BM endothelial niche, and their molecular phenotype shifted from dormant to awaken. Following estrogen depletion, the BM niche cells produced angiopoietin-2 (ANGPT2), which destabilized niche endothelium by interfering ANGPT1/Tie2 signaling, and promoted ER+ tumor cell survival under estrogen deficiency via cell surface integrin β1. Knockdown of ANGPT2 completely negated ER+ tumor cell awakening in the niche. Furthermore, ANGPT2 expression in ER+ tumor human samples was associated with increased risk of distant metastasis only in those who underwent adjuvant estrogen depletion therapy, not in those who did not undergo adjuvant therapy. In conclusion, we demonstrate that ANGPT2 signaling activated after estrogen depletion paradoxically triggers ER+ tumor cell awakening from dormancy in their BM niche, partly indirectly via endothelial Tie2 receptor and partly directly via tumor cell surface integrin β1.
Milena Rondón-Lagos, Nelson Rangel, Ludovica Verdun Di Cantogno, Laura Annaratone, Isabella Castellano, Rosalia Russo, Tilde Manetta, Caterina Marchiò, and Anna Sapino
Evidence supports a role of 17&-estradiol (E2) in carcinogenesis and the large majority of breast carcinomas are dependent on estrogen. The anti-estrogen tamoxifen (TAM) is widely used for both treatment and prevention of breast cancer; however, it is also carcinogenic in human uterus and rat liver, highlighting the profound complexity of its actions. The nature of E2- or TAM-induced chromosomal damage has been explored using relatively high concentrations of these agents, and only some numerical aberrations and chromosomal breaks have been analyzed. This study aimed to determine the effects of low doses of E2 and TAM (10&8 mol L&1 and 10&6 mol L&1 respectively) on karyotypes of MCF7, T47D, BT474, and SKBR3 breast cancer cells by comparing the results of conventional karyotyping and multi-FISH painting with cell proliferation. Estrogen receptor (ER)-positive (+) cells showed an increase in cell proliferation after E2 treatment (MCF7, T47D, and BT474) and a decrease after TAM treatment (MCF7 and T47D), whereas in ER& cells (SKBR3), no alterations in cell proliferation were observed, except for a small increase at 96 h. Karyotypes of both ER+ and ER& breast cancer cells increased in complexity after treatments with E2 and TAM leading to specific chromosomal abnormalities, some of which were consistent throughout the treatment duration. This genotoxic effect was higher in HER2+ cells. The ER&/HER2+ SKBR3 cells were found to be sensitive to TAM, exhibiting an increase in chromosomal aberrations. These in vitro results provide insights into the potential role of low doses of E2 and TAM in inducing chromosomal rearrangements in breast cancer cells.
Thomas Cuny, Caroline Zeiller, Martin Bidlingmaier, Céline Défilles, Catherine Roche, Marie-Pierre Blanchard, Marily Theodoropoulou, Thomas Graillon, Morgane Pertuit, Dominique Figarella-Branger, Alain Enjalbert, Thierry Brue, and Anne Barlier
Pegvisomant (PEG), an antagonist of growth hormone (GH)-receptor (GHR), normalizes insulin-like growth factor 1 (IGF1) oversecretion in most acromegalic patients unresponsive to somatostatin analogs (SSAs) and/or uncontrolled by transsphenoidal surgery. The residual GH-secreting tumor is therefore exposed to the action of circulating PEG. However, the biological effect of PEG at the pituitary level remains unknown. To assess the impact of PEG in vitro on the hormonal secretion (GH and prolactin (PRL)), proliferation and cellular viability of eight human GH-secreting tumors in primary cultures and of the rat somatolactotroph cell line GH4C1. We found that the mRNA expression levels of GHR were characterized in 31 human GH-secreting adenomas (0.086 copy/copy β-Gus) and the GHR was identified by immunocytochemistry staining. In 5/8 adenomas, a dose-dependent inhibition of GH secretion was observed under PEG with a maximum of 38.2±17% at 1μg/mL (P<0.0001 vs control). A dose-dependent inhibition of PRL secretion occurred in three mixed GH/PRL adenomas under PEG with a maximum of 52.8±11.5% at 10μg/mL (P<0.0001 vs control). No impact on proliferation of either human primary tumors or GH4C1 cell line was observed. We conclude that PEG inhibits the secretion of GH and PRL in primary cultures of human GH(/PRL)-secreting pituitary adenomas without effect on cell viability or cell proliferation.
Birgit Luef, Florian Handle, Gvantsa Kharaishvili, Martina Hager, Johannes Rainer, Günter Janetschek, Stephan Hruby, Christine Englberger, Jan Bouchal, Frédéric R Santer, and Zoran Culig
Due to the urgent need for new prostate cancer (PCa) therapies, the role of androgen receptor (AR)-interacting proteins should be investigated. In this study we aimed to address whether the AR coactivator nuclear receptor coactivator 1 (NCOA1) is involved in PCa progression. Therefore, we tested the effect of long-term NCOA1 knockdown on processes relevant to metastasis formation. [3H]-thymidine incorporation assays revealed a reduced proliferation rate in AR-positive MDA PCa 2b and LNCaP cells upon knockdown of NCOA1, whereas AR-negative PC3 cells were not affected. Furthermore, Boyden chamber assays showed a strong decrease in migration and invasion upon NCOA1 knockdown, independently of the cell line’s AR status. In order to understand the mechanistic reasons for these changes, transcriptome analysis using cDNA microarrays was performed. Protein kinase D1 (PRKD1) was found to be prominently up-regulated by NCOA1 knockdown in MDA PCa 2b, but not in PC3 cells. Inhibition of PRKD1 reverted the reduced migratory potential caused by NCOA1 knockdown. Furthermore, PRKD1 was negatively regulated by AR. Immunohistochemical staining of PCa patient samples revealed a strong increase in NCOA1 expression in primary tumors compared with normal prostate tissue, while no final conclusion could be drawn for PRKD1 expression in tumor specimens. Thus, our findings directly associate the AR/NCOA1 complex with PRKD1 regulation and cellular migration and support the concept of therapeutic inhibition of NCOA1 in PCa.
Martyn E Caplin, Marianne Pavel, Jarosław B Ćwikła, Alexandria T Phan, Markus Raderer, Eva Sedláčková, Guillaume Cadiot, Edward M Wolin, Jaume Capdevila, Lucy Wall, Guido Rindi, Alison Langley, Séverine Martinez, Edda Gomez-Panzani, Philippe Ruszniewski, and on behalf of the CLARINET Investigators
In the CLARINET study, lanreotide Autogel (depot in USA) significantly prolonged progression-free survival (PFS) in patients with metastatic pancreatic/intestinal neuroendocrine tumours (NETs). We report long-term safety and additional efficacy data from the open-label extension (OLE). Patients with metastatic grade 1/2 (Ki-67 ≤10%) non-functioning NET and documented baseline tumour-progression status received lanreotide Autogel 120 mg (n=101) or placebo (n=103) for 96 weeks or until death/progressive disease (PD) in CLARINET study. Patients with stable disease (SD) at core study end (lanreotide/placebo) or PD (placebo only) continued or switched to lanreotide in the OLE. In total, 88 patients (previously: lanreotide, n=41; placebo, n=47) participated: 38% had pancreatic, 39% midgut and 23% other/unknown primary tumours. Patients continuing lanreotide reported fewer adverse events (AEs) (all and treatment-related) during OLE than core study. Placebo-to-lanreotide switch patients reported similar AE rates in OLE and core studies, except more diarrhoea was considered treatment-related in OLE (overall diarrhoea unchanged). Median lanreotide PFS (core study randomisation to PD in core/OLE; n=101) was 32.8 months (95% CI: 30.9, 68.0). A sensitivity analysis, addressing potential selection bias by assuming that patients with SD on lanreotide in the core study and not entering the OLE (n=13) had PD 24 weeks after last core assessment, found median PFS remaining consistent: 30.8 months (95% CI: 30.0, 31.3). Median time to further PD after placebo-to-lanreotide switch (n=32) was 14.0 months (10.1; not reached). This OLE study suggests long-term treatment with lanreotide Autogel 120 mg maintained favourable safety/tolerability. CLARINET OLE data also provide new evidence of lanreotide anti-tumour benefits in indolent and progressive pancreatic/intestinal NETs.
Kristina Warton, Kate L Mahon, and Goli Samimi
Circulating tumor DNA (ctDNA) in the plasma or serum of cancer patients provides an opportunity for non-invasive sampling of tumor DNA. This ‘liquid biopsy’ allows for interrogations of DNA such as quantity, chromosomal alterations, sequence mutations and epigenetic changes, and can be used to guide and improve treatment throughout the course of the disease. This tremendous potential for real-time ‘tracking’ in a cancer patient has led to substantial research efforts in the ctDNA field. ctDNA can be distinguished from non-tumor DNA by the presence of tumor-specific mutations and copy number variations, and also by aberrant DNA methylation, with both DNA sequence and methylation changes corresponding to those found in the tumor. Aberrant methylation of specific promoter regions can be a very consistent feature of cancer, in contrast to mutations, which typically occur at a wide range of sites. This consistency makes ctDNA methylation amenable to the design of widely applicable clinical assays. In this review, we examine ctDNA methylation in the context of monitoring disease status, treatment response and determining the prognosis of cancer patients.
Deborah J Thompson, Tracy A O'Mara, Dylan M Glubb, Jodie N Painter, Timothy Cheng, Elizabeth Folkerd, Deborah Doody, Joe Dennis, Penelope M Webb, for the Australian National Endometrial Cancer Study Group (ANECS), Maggie Gorman, Lynn Martin, Shirley Hodgson, for the National Study of Endometrial Cancer Genetics Group (NSECG), Kyriaki Michailidou, Jonathan P Tyrer, Mel J Maranian, Per Hall, Kamila Czene, Hatef Darabi, Jingmei Li, Peter A Fasching, Alexander Hein, Matthias W Beckmann, Arif B Ekici, Thilo Dörk, Peter Hillemanns, Matthias Dürst, Ingo Runnebaum, Hui Zhao, Jeroen Depreeuw, Stefanie Schrauwen, Frederic Amant, Ellen L Goode, Brooke L Fridley, Sean C Dowdy, Stacey J Winham, Helga B Salvesen, Jone Trovik, Tormund S Njolstad, Henrica M J Werner, Katie Ashton, Tony Proietto, Geoffrey Otton, Luis Carvajal-Carmona, Emma Tham, Tao Liu, Miriam Mints, for RENDOCAS, Rodney J Scott, Mark McEvoy, John Attia, Elizabeth G Holliday, Grant W Montgomery, Nicholas G Martin, Dale R Nyholt, Anjali K Henders, John L Hopper, Nadia Traficante, for the AOCS Group, Matthias Ruebner, Anthony J Swerdlow, Barbara Burwinkel, Hermann Brenner, Alfons Meindl, Hiltrud Brauch, Annika Lindblom, Diether Lambrechts, Jenny Chang-Claude, Fergus J Couch, Graham G Giles, Vessela N Kristensen, Angela Cox, Manjeet K Bolla, Qin Wang, Stig E Bojesen, Mitul Shah, Robert Luben, Kay-Tee Khaw, Paul D P Pharoah, Alison M Dunning, Ian Tomlinson, Mitch Dowsett, Douglas F Easton, and Amanda B Spurdle
Candidate gene studies have reported CYP19A1 variants to be associated with endometrial cancer and with estradiol (E2) concentrations. We analyzed 2937 single nucleotide polymorphisms (SNPs) in 6608 endometrial cancer cases and 37 925 controls and report the first genome wide-significant association between endometrial cancer and a CYP19A1 SNP (rs727479 in intron 2, P=4.8×10−11). SNP rs727479 was also among those most strongly associated with circulating E2 concentrations in 2767 post-menopausal controls (P=7.4×10−8). The observed endometrial cancer odds ratio per rs727479 A-allele (1.15, CI=1.11–1.21) is compatible with that predicted by the observed effect on E2 concentrations (1.09, CI=1.03–1.21), consistent with the hypothesis that endometrial cancer risk is driven by E2. From 28 candidate-causal SNPs, 12 co-located with three putative gene-regulatory elements and their risk alleles associated with higher CYP19A1 expression in bioinformatical analyses. For both phenotypes, the associations with rs727479 were stronger among women with a higher BMI (P interaction=0.034 and 0.066 respectively), suggesting a biologically plausible gene-environment interaction.