Somatostatin receptor-targeting endoradiotherapy offers potential for treating metastatic pheochromocytomas and paragangliomas, an approach likely to benefit from combination radiosensitization therapy. To provide reliable preclinical in vivo models of metastatic disease, this study characterized the metastatic spread of luciferase-expressing mouse pheochromocytoma (MPC) cells in mouse strains with different immunologic conditions. Bioluminescence imaging showed that, in contrast to subcutaneous non-metastatic engraftment of luciferase-expressing MPC cells in NMRI-nude mice, intravenous cell injection provided only suboptimal metastatic spread in both NMRI-nude mice and hairless SCID (SHO) mice. Treatment of NMRI-nude mice with anti-Asialo GM1 serum enhanced metastatic spread due to substantial depletion of natural killer (NK) cells. However, reproducible metastatic spread was only observed in NK cell-defective SCID/beige mice and in hairless immunocompetent SKH1 mice bearing disseminated or liver metastases, respectively. Liquid chromatography tandem mass spectrometry of urine samples showed that subcutaneous and metastasized tumor models exhibit comparable renal monoamine excretion profiles characterized by increasing urinary dopamine, 3-methoxytyramine, norepinephrine and normetanephrine. Metastases-related epinephrine and metanephrine were only detectable in SCID/beige mice. Positron emission tomography and immunohistochemistry revealed that all metastases maintained somatostatin receptor-specific radiotracer uptake and immunoreactivity, respectively. In conclusion, we demonstrate that intravenous injection of luciferase-expressing MPC cells into SCID/beige and SKH1 mice provides reproducible and clinically relevant spread of catecholamine-producing and somatostatin receptor-positive metastases. These standardized preclinical models allow for precise monitoring of disease progression and should facilitate further investigations on theranostic approaches against metastatic pheochromocytomas and paragangliomas.
Martin Ullrich, Josephine Liers, Mirko Peitzsch, Anja Feldmann, Ralf Bergmann, Ulrich Sommer, Susan Richter, Stefan R Bornstein, Michael Bachmann, Graeme Eisenhofer, Christian G Ziegler and Jens Pietzsch
Jonathan W Nyce
The activation of TP53 is well known to exert tumor suppressive effects. We have detected a primate-specific adrenal androgen-mediated tumor suppression system in which circulating DHEAS is converted to DHEA specifically in cells in which TP53 has been inactivated. DHEA is an uncompetitive inhibitor of glucose-6-phosphate dehydrogenase (G6PD), an enzyme indispensable for maintaining reactive oxygen species within limits survivable by the cell. Uncompetitive inhibition is otherwise unknown in natural systems because it becomes irreversible in the presence of high concentrations of substrate and inhibitor. In addition to primate-specific circulating DHEAS, a unique, primate-specific sequence motif that disables an activating regulatory site in the glucose-6-phosphatase (G6PC) promoter was also required to enable function of this previously unrecognized tumor suppression system. In human somatic cells, loss of TP53 thus triggers activation of DHEAS transport proteins and steroid sulfatase, which converts circulating DHEAS into intracellular DHEA, and hexokinase which increases glucose-6-phosphate substrate concentration. The triggering of these enzymes in the TP53-affected cell combines with the primate-specific G6PC promoter sequence motif that enables G6P substrate accumulation, driving uncompetitive inhibition of G6PD to irreversibility and ROS-mediated cell death. By this catastrophic ‘kill switch’ mechanism, TP53 mutations are effectively prevented from initiating tumorigenesis in the somatic cells of humans, the primate with the highest peak levels of circulating DHEAS. TP53 mutations in human tumors therefore represent fossils of kill switch failure resulting from an age-related decline in circulating DHEAS, a potentially reversible artifact of hominid evolution.
Jonathan Wesley Nyce
A here-to-fore unknown tumor suppression mechanism reached its greatest expression in humans, having evolved to protect during the twenty-five-year lifespan of primitive humans. It depends upon high levels of circulating DHEAS and its importation into cells that have experienced inactivation of TP53, whereupon DHEAS is desulfated to DHEA, an uncompetitive inhibitor of Glucose-6-phosphate Dehydrogenase (G6PD). Uncompetitive inhibition of G6PD becomes irreversible in the presence of high levels of inhibitor and substrate (G6P). We reported an anthropoid primate-specific sequence motif in the Glucose-6-phosphatase (G6PC) promoter that enables intercellular G6P to accumulate to concentrations sufficient to induce irreversible uncompetitive inhibition of G6PD. We now conclude that inactivation of Gulonolactone Oxidase (GLO), a primate-specific event resulting in vitamin C auxotrophy, also contributed to kill switch evolution by enabling G6P accumulation. Unique mechanisms of tumor suppression appear to distinguish all vertebrate species, preventing ‘one vertebrate species from serving as a valid model system for another’. This unrecognized element of speciation undermines decades of cancer research data, using murine species, that presumed universal mechanisms of tumor suppression, independent of species. Despite this setback, the potential for pharmacological reconstitution of the kill switch tumor suppression system that distinguishes our species suggests that “normalization” of human cancer risk, from its current 40% to the 4% of virtually all other large, long-lived species, represents a realistic near-term goal.
Frederic Castinetti, Frederique Albarel, Francoise Archambeaud, Jerome Bertherat, Benjamin Bouillet, Perrine Buffier, Claire Briet, Bertrand Cariou, Philippe Caron, Olivier Chabre, Philippe Chanson, Christine Cortet, Christine Do Cao, Delphine Drui, Magali Haissaguerre, Segolene Hescot, Frederic Illouz, Emmanuelle Kuhn, Najiba Lahlou, Emilie Merlen, Veronique Raverot, Sarra Smati, Bruno Verges and Françoise Borson-Chazot
The management of cancer patients has changed due to the considerably more frequent use of immune checkpoint inhibitors (ICPI). However, the use of ICPI has a risk of side-effects, particularly endocrine toxicity. Since the indications for ICPI are constantly expanding due to their efficacy, it is important that endocrinologists and oncologists know how to look for this type of toxicity and how to treat it when it arises. In view of this, the French Endocrine Society initiated the formulation of a consensus document on ICPI-related endocrine toxicity. In this paper, we will introduce data on the general pathophysiology of endocrine toxicity, we will then outline expert opinion focusing primarily on methods for screening, management and monitoring for endocrine side-effects in patients treated by ICPI. We will then look in turn at endocrinopathies that are induced by ICPI including dysthyroidism, hypophysitis, primary adrenal insufficiency and fulminant diabetes. In each chapter, expert opinion will be given on the diagnosis, management and monitoring for each complication. These expert opinions will also discuss the methodology for categorizing these side-effects in oncology using ‘Common terminology criteria for adverse events’ (CTCAE) and the difficulties in applying this to endocrine side-effects in the case of these anti-cancer therapies. This is shown in particular by certain recommendations that are used for other side-effects (high-dose corticosteroids, contra-indicated in ICPI for example), and that cannot be considered as appropriate in the management of endocrine toxicity, as it usually does not require ICPI withdrawal or high dose glucocorticoid intake .
Abigail Read and Rachael Natrajan
Breast cancer is known to be a heterogeneous disease driven by a large repertoire of molecular abnormalities, which contribute to its diverse clinical behaviour. Despite the success of targeted therapy approaches for breast cancer patient management, there is still a lack of the molecular understanding of aggressive forms of the disease and clinical management of these patients remains difficult. The advent of high-throughput sequencing technologies has paved the way for a more complete understanding of the molecular make-up of the breast cancer genome. As such, it is becoming apparent that disruption of canonical splicing within breast cancer governs its clinical progression. In this review, we discuss the role of dysregulation of spliceosomal component genes and associated factors in the progression of breast cancer, their role in therapy resistance and the use of quantitative isoform expression as potential prognostic and predictive biomarkers with a particular focus on oestrogen receptor-positive breast cancer.
Samuel M O'Toole, David S Watson, Tatiana V Novoselova, Lisa E L Romano, Peter King, Teisha Y Bradshaw, Clare L Thompson, Martin M Knight, Tyson V Sharp, Michael R Barnes, Umasuthan Srirangalingam, William Drake and J Paul Chapple
Primary cilia are sensory organelles involved in regulation of cellular signalling. Cilia loss is frequently observed in tumors, yet the responsible mechanisms and consequences for tumorigenesis remain unclear. We demonstrate that cilia structure and function is disrupted in human pheochromocytomas - endocrine tumours of the adrenal medulla. This is concomitant with transcriptional changes within cilia mediated signalling pathways that are associated with tumorigenesis generally and pheochromocytomas specifically. Importantly, cilia loss was most dramatic in patients with germline mutations in the pseudohypoxia-linked genes SDHx and VHL. Using a pheochromocytoma cell line derived from rat, we show that hypoxia and oncometabolite induced pseudohypoxia are key drivers of cilia loss and identify that this is dependent on activation of an AuroraA/HDAC6 cilia resorption pathway. We also show cilia loss drives dramatic transcriptional changes associated with proliferation and tumorigenesis. Our data provide evidence for primary cilia dysfunction contributing to pathogenesis of pheochromocytoma by a hypoxic/pseudohypoxic mechanism and implicates oncometabolites as ciliary regulators. This is important as pheochromocytomas can cause mortality by mechanisms including catecholamine production and malignant transformation, while hypoxia is a general feature of solid tumours. Moreover, pseudohypoxia induced cilia resorption can be pharmacologically inhibited, suggesting potential for therapeutic intervention.
Paraskevi Xekouki, Emily Jane Lodge, Jakob Matschke, Alice Santambrogio, John R Apps, Ariane Sharif, Thomas S Jacques, Simon Aylwin, Vincent Prevot, Ran Li, Jörg Flitsch, Stefan R Bornstein, Marily Theodoropoulou and Cynthia Andoniadou
Tumours of the anterior pituitary can manifest from all endocrine cell types but the mechanisms for determining their specification are not known. The Hippo kinase cascade is a crucial signalling pathway regulating growth and cell fate in numerous organs. There is mounting evidence implicating this in tumour formation, where it is emerging as an anti-cancer target. We previously demonstrated activity of the Hippo kinase cascade in the mouse pituitary and nuclear association of its effectors YAP/TAZ with SOX2-expressing pituitary stem cells. Here we sought to investigate whether these components are expressed in the human pituitary and if they are deregulated in human pituitary tumours. Analysis of pathway components by immunofluorescence reveals pathway activity during normal human pituitary development and in the adult gland. Poorly differentiated pituitary tumours (null cell adenomas, adamantinomatous craniopharyngiomas (ΑCPs) and papillary craniopharyngiomas (PCPs)), displayed enhanced expression of pathway effectors YAP/TAZ. In contrast, differentiated adenomas displayed lower or absent levels. Knock-down of the kinase-encoding Lats1 in GH3 rat mammosomatotropinoma cells suppressed Prl and Gh promoter activity following an increase in YAP/TAZ levels. In conclusion, we have demonstrated activity of the Hippo kinase cascade in the human pituitary and association of high YAP/TAZ with repression of the differentiated state both in vitro and in vivo. Characterisation of this pathway in pituitary tumours is of potential prognostic value, opening up putative avenues for treatments.
Xianhui Ruan, Xianle Shi, Qiman Dong, Yang Yu, Xiukun Hou, Xinhao Song, Xi Wei, Lingyi Chen and Ming Gao
There is no effective treatment for patients with poorly differentiated papillary thyroid cancer or anaplastic thyroid cancer (ATC). Anlotinib, a multi-kinase inhibitor, has already shown antitumor effects in various types of carcinoma in a phase I clinical trial. In this study, we aimed to better understand the effect and efficacy of anlotinib against thyroid carcinoma cells in vitro and in vivo. We found that anlotinib inhibits the cell viability of papillary thyroid cancer and ATC cell lines, likely due to abnormal spindle assembly, G2/M arrest, and activation of TP53 upon anlotinib treatment. Moreover, anlotinib suppresses the migration of thyroid cancer cells in vitro and the growth of xenograft thyroid tumors in mice. Our data demonstrate that anlotinib has significant anti-cancer activity in thyroid cancer, and potentially offers an effective therapeutic strategy for patients of advanced thyroid cancer type.
Claudia Tulotta and Penelope Ottewell
Approximately 75% of patients with late-stage breast cancer will develop bone metastasis. This condition is currently considered incurable and patients’ life expectancy is limited to 2–3 years following diagnosis of bone involvement. Interleukin (IL)-1B is a pro-inflammatory cytokine whose expression in primary tumours has been identified as a potential biomarker for predicting breast cancer patients at increased risk for developing bone metastasis. In this review, we discuss how IL-1B from both the tumour cells and the tumour microenvironment influence growth of primary breast tumours, dissemination into the bone metastatic niche and proliferation into overt metastases. Recent evidence indicates that targeting IL-1B signalling may provide promising new treatments that can hold tumour cells in a dormant state within bone thus preventing formation of overt bone metastases.
J Crona, F Beuschlein, K Pacak and B Skogseid
This review aims to provide clinicians and researchers with a condensed update on the most important studies in the field during 2017. We present the academic output measured by active clinical trials and peer-reviewed published manuscripts. The most important and contributory manuscripts were summarized for each diagnostic entity, with a particular focus on manuscripts that describe translational research that have the potential to improve clinical care. Finally, we highlight the importance of collaborations in adrenal tumor research, which allowed for these recent advances and provide structures for future success in this scientific field.