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Open access

Salma Kaochar, Aleksandra Rusin, Christopher Foley, Kimal Rajapakshe, Matthew Robertson, Darlene Skapura, Cammy Mason, Karen Berman De Ruiz, Alexey Mikhailovich Tyryshkin, Jenny Deng, Jin Na Shin, Warren Fiskus, Jianrong Dong, Shixia Huang, Nora M Navone, Christel M Davis, Erik A Ehli, Cristian Coarfa, and Nicholas Mitsiades

Castration-resistant prostate cancer (CRPC) remains highly lethal and in need of novel, actionable therapeutic targets. The pioneer factor GATA2 is a significant prostate cancer (PC) driver and is linked to poor prognosis. GATA2 directly promotes androgen receptor (AR) gene expression (both full-length and splice-variant) and facilitates AR binding to chromatin, recruitment of coregulators, and target gene transcription. Unfortunately, there is no clinically applicable GATA2 inhibitor available at the moment. Using a bioinformatics algorithm, we screened in silico 2650 clinically relevant drugs for a potential GATA2 inhibitor. Validation studies used cytotoxicity and proliferation assays, global gene expression analysis, RT-qPCR, reporter assay, reverse phase protein array analysis (RPPA), and immunoblotting. We examined target engagement via cellular thermal shift assay (CETSA), ChIP-qPCR, and GATA2 DNA-binding assay. We identified the vasodilator dilazep as a potential GATA2 inhibitor and confirmed on-target activity via CETSA. Dilazep exerted anticancer activity across a broad panel of GATA2-dependent PC cell lines in vitro and in a PDX model in vivo. Dilazep inhibited GATA2 recruitment to chromatin and suppressed the cell-cycle program, transcriptional programs driven by GATA2, AR, and c-MYC, and the expression of several oncogenic drivers, including AR, c-MYC, FOXM1, CENPF, EZH2, UBE2C, and RRM2, as well as of several mediators of metastasis, DNA damage repair, and stemness. In conclusion, we provide, via an extensive compendium of methodologies, proof-of-principle that a small molecule can inhibit GATA2 function and suppress its downstream AR, c-MYC, and other PC-driving effectors. We propose GATA2 as a therapeutic target in CRPC.

Open access

Andreas Venizelos, Hege Elvebakken, Aurel Perren, Oleksii Nikolaienko, Wei Deng, Inger Marie B Lothe, Anne Couvelard, Geir Olav Hjortland, Anna Sundlöv, Johanna Svensson, Harrish Garresori, Christian Kersten, Eva Hofsli, Sönke Detlefsen, Merete Krogh, Halfdan Sorbye, and Stian Knappskog

High-grade (HG) gastroenteropancreatic (GEP) neuroendocrine neoplasms (NEN) are rare but have a very poor prognosis and represent a severely understudied class of tumours. Molecular data for HG GEP-NEN are limited, and treatment strategies for the carcinoma subgroup (HG GEP-NEC) are extrapolated from small-cell lung cancer (SCLC). After pathological re-evaluation, we analysed DNA from tumours and matched blood samples from 181 HG GEP-NEN patients; 152 neuroendocrine carcinomas (NEC) and 29 neuroendocrine tumours (NET G3). Based on the sequencing of 360 cancer-related genes, we assessed mutations and copy number alterations (CNA). For NEC, frequently mutated genes were TP53 (64%), APC (28%), KRAS (22%) and BRAF (20%). RB1 was only mutated in 14%, but CNAs affecting RB1 were seen in 34%. Other frequent copy number losses were ARID1A (35%), ESR1 (25%) and ATM (31%). Frequent amplifications/gains were found in MYC (51%) and KDM5A (45%). While these molecular features had limited similarities with SCLC, we found potentially targetable alterations in 66% of the NEC samples. Mutations and CNA varied according to primary tumour site with BRAF mutations mainly seen in colon (49%), and FBXW7 mutations mainly seen in rectal cancers (25%). Eight out of 152 (5.3%) NEC were microsatellite instable (MSI). NET G3 had frequent mutations in MEN1 (21%), ATRX (17%), DAXX, SETD2 and TP53 (each 14%). We show molecular differences in HG GEP-NEN, related to morphological differentiation and site of origin. Limited similarities to SCLC and a high fraction of targetable alterations indicate a high potential for better-personalized treatments.

Free access

Tania Moujaber, Rosemary L Balleine, Bo Gao, Ida Madsen, Paul R Harnett, and Anna DeFazio

Low-grade serous ovarian cancer (LGSC) is a morphologically and molecularly distinct subtype of ovarian cancer, accounting for ~10% of serous carcinomas. Women typically present at a younger age and have a protracted clinical course compared with the more common, high-grade serous ovarian cancer. Currently, the primary treatment of LGSC is the same as other epithelial ovarian cancer subtypes, with treatment for most patients comprised of debulking surgery and platinum/taxane chemotherapy. Primary surgical cytoreduction to no visible residual disease remains a key prognostic factor; however, the use of platinum-based chemotherapy in both upfront and relapsed setting is being questioned due to low response rates in LGSC. Most LGSC expresses steroid hormone receptors, and selected patients may benefit from endocrine maintenance therapy following chemotherapy, in particular, those with evidence of residual disease at completion of surgery. In the recurrent setting, while hormonal therapies may offer disease stabilisation with relatively low toxicity, objective response rates remain low. Strategies to increase response rates, including combining with CDK4/6 inhibitors, are being investigated. LGSC has a high prevalence of activating somatic mutations in mitogen-activated protein kinase pathway genes, most commonly in KRAS, BRAF and NRAS. Trametinib, a MEK inhibitor, has shown efficacy over chemotherapy and endocrine therapy. The use of combination targeted therapies, immunotherapy and anti-angiogenic agents, remain active areas of investigation for the treatment of LGSC.

Free access

Courtney A Dreyer, Kacey VanderVorst, Savannah Free, Ashley Rowson-Hodel, and Kermit L Carraway III

A major barrier to the emergence of distant metastases is the survival of circulating tumor cells (CTCs) within the vasculature. Lethal stressors, including shear forces from blood flow, anoikis arising from cellular detachment, and exposure to natural killer cells, combine to subvert the ability of primary tumor cells to survive and ultimately seed distant lesions. Further attenuation of this rate-limiting process via therapeutic intervention offers a very attractive opportunity for improving cancer patient outcomes, in turn prompting the need for a deeper understanding of the molecular and cellular mechanisms underlying CTC viability. MUC4 is a very large and heavily glycosylated protein expressed at the apical surfaces of the epithelia of a variety of tissues, is involved in cellular growth signaling and adhesiveness, and contributes to the protection and lubrication of cellular linings. Analysis of patient-matched breast tumor specimens has demonstrated that MUC4 protein levels are upregulated in metastatic lesions relative to primary tumor among all breast tumor subtypes, pointing to a possible selective advantage for MUC4 overexpression in metastasis. Analysis of a genetically engineered mouse model of HER2-positive breast cancer has demonstrated that metastatic efficiency is markedly suppressed with Muc4 deletion and Muc4-knockout tumor cells are poorly associated with platelets and white blood cells known to support CTC viability. In this review, we discuss the diverse roles of MUC4 in tumor progression and metastasis and propose that intervening in MUC4 intercellular interactions with binding partners on blood-borne aggregating cells could potentially thwart breast cancer metastatic efficiency.

Restricted access

Mojun Zhu, Karl R Sorenson, Rebecca Liu, Bonnie E Gould Rothberg, and Thorvardur R Halfdanarson

Pancreatic neuroendocrine tumors (PNETs) encompass a diverse group of malignancies marked by histological heterogeneity and highly variable clinical outcomes. We performed a systematic review on potential prognostic biomarkers in PNETs by searching the PubMed database. A total of 472 manuscripts were reviewed in detail, of which 52 multivariate studies met the inclusion criteria proposed by the Reporting Recommendations for Tumor Marker Prognostic Studies. These altogether analyzed 53 unique targets, and 36 of them were statistically associated with survival.

Open access

Luise Eckardt, Maria Prange-Barczynska, Emma J Hodson, James W Fielding, Xiaotong Cheng, Joanna D C C Lima, Samvid Kurlekar, Gillian Douglas, Peter J Ratcliffe, and Tammie Bishop

Despite a general role for the HIF hydroxylase system in cellular oxygen sensing and tumour hypoxia, cancer-associated mutations of genes in this pathway, including PHD2, PHD1, EPAS1 (encoding HIF-2α) are highly tissue-restricted, being observed in pseudohypoxic pheochromocytoma and paraganglioma (PPGL) but rarely, if ever, in other tumours. In an effort to understand that paradox and gain insights into the pathogenesis of pseudohypoxic PPGL, we constructed mice in which the principal HIF prolyl hydroxylase, Phd2, is inactivated in the adrenal medulla using TH-restricted Cre recombinase. Investigation of these animals revealed a gene expression pattern closely mimicking that of pseudohypoxic PPGL. Spatially resolved analyses demonstrated a binary distribution of two contrasting patterns of gene expression among adrenal medullary cells. Phd2 inactivation resulted in a marked shift in this distribution towards a Pnmt /Hif-2α +/Rgs5 + population. This was associated with morphological abnormalities of adrenal development, including ectopic TH+ cells within the adrenal cortex and external to the adrenal gland. These changes were ablated by combined inactivation of Phd2 with Hif-2α, but not Hif-1α. However, they could not be reproduced by inactivation of Phd2 in adult life, suggesting that they arise from dysregulation of this pathway during adrenal development. Together with the clinical observation that pseudohypoxic PPGL manifests remarkably high heritability, our findings suggest that this type of tumour likely arises from dysregulation of a tissue-restricted action of the PHD2/HIF-2α pathway affecting adrenal development in early life and provides a model for the study of the relevant processes.

Restricted access

Pedro Iglesias, Inmaculada Peiró, Betina Biagetti, Miguel Paja-Fano, Diana Ariadel Cobo, Carlos García Gómez, Manuel Mateu-Salat, Idoia Genua, Margarita Majem, Mariona Riudavets, Javier Gavira, Cristina Lamas, Antía Fernández Pombo, Fernando Guerrero-Pérez, Carles Villabona, José Manuel Cabezas Agrícola, Susan M Webb, and Juan J Díez

Central adrenal insufficiency (AI) due to isolated adrenocorticotropic hormone (ACTH) deficiency (IAD) has been recently associated with immune checkpoint inhibitor (ICI) therapy. Our aim was to analyze the prevalence, clinical characteristics, and therapeutic outcomes in cancer patients with IAD induced by ICI therapy. A retrospective and multicenter study was performed. From a total of 4447 cancer patients treated with ICI antibodies, 37 (0.8%) (23 men (62.2%), mean age 64.7 ± 8.3 years (range 46–79 years)) were diagnosed with IAD. The tumor most frequently related to IAD was lung cancer (n = 20, 54.1%), followed by melanoma (n = 8, 21.6%). The most common ICI antibody inhibitors reported were nivolumab (n = 18, 48.6%), pembrolizumab (n = 16, 43.2%), and ipilimumab (n = 8, 21.6%). About half of the patients (n = 19, 51.4%) had other immune-related adverse events, mainly endocrine adverse effects (n = 10, 27.0%). IAD was diagnosed at a median time of 7.0 months (IQR, 5–12) after starting immunotherapy. The main reported symptom at presentation was fatigue (97.3%), followed by anorexia (81.8%) and general malaise (81.1%). Mean follow-up time since IAD diagnosis was 15.2 ± 12.5 months (range 0.3–55 months). At last visit, all patients continued with hormonal deficiency of ACTH. Median overall survival since IAD diagnosis was 6.0 months. In conclusion, IAD is a rare but a well-established complication associated with ICI therapy in cancer patients. It develops around 7 months after starting the treatment, mainly anti-PD1 antibodies. Recovery of the corticotropic axis function should not be expected.

Free access

James F H Pittaway, Constantinos Lipsos, Katia Mariniello, and Leonardo Guasti

Delta-like non-canonical Notch ligand 1 (DLK1) is a cleavable single-pass transmembrane protein and a member of the Notch/Delta/Serrate family. It is paternally expressed and belongs to a group of imprinted genes located on chromosome band 14q32 in humans and 12qF1 in mice. DLK1 is expressed in many human tissues during embryonic development but in adults expression is low and is mostly restricted to (neuro)endocrine tissues and other immature stem/progenitor cells (notably hepatoblasts). However, DLK1 is expressed at a high frequency in many common malignancies (liver, breast, brain, pancreas, colon and lung). More recently, high levels of expression have been identified in endocrine-related cancers such as ovarian and adrenocortical carcinoma. There is growing evidence that DLK1 expression in cancer is associated with worse prognosis and that DLK1 may be a marker of cancer stem cells. Although the exact mechanism through which DLK1 functions is not fully understood, it is known to maintain cells in an undifferentiated phenotype and has oncogenic properties. These effects are partly exacted through interaction with the Notch signalling pathway. In this review, we have detailed the functional role of DLK1 within physiology and malignancy and posited a mechanism for how it exacts its oncogenic effects. In describing the expression of DLK1 in cancer and in healthy tissue, we have highlighted the potential for its use both as a biomarker and as a potential therapeutic target.

Restricted access

Arianna Ventura-Bahena, Jesús Gibran Hernández-Pérez, Luisa Torres-Sánchez, Adolfo Sierra-Santoyo, Derly Constanza Escobar-Wilches, Consuelo Escamilla-Núñez, Rocio Gómez, Francisco Rodríguez-Covarrubias, Ma. de Lourdes López-González, and Mario Figueroa

Epidemiological studies related to androgens and prostate cancer (PC) have focused on serum determination of testosterone, androstenedione (A4), and DHEA, with inconsistent results. Herein, we hypothesized that differences in androgen biosynthetic and metabolic pathways, rather than differences in specific androgen concentrations, are associated with prostatic carcinogenesis. Therefore, spot urine samples from 111 incident PC cases with Gleason score at diagnosis and 227 healthy population controls, were analyzed. Urinary androgen concentrations (nanograms/milligrams of creatinine) were determined by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS). Using a factor analysis, we identified three androgen urinary excretion patterns. In a subsample, we evaluated a modification effect of the androgen receptor (AR) CAG polymorphism. Pattern I, characterized by A4 and testosterone hydroxylated metabolites (11β-OHT; 2β-OHT; 15β-OHT; 2α-OHT; 6β-OHT), was associated with high PC odds among carriers of AR gene (CAG)>19 repeats (OR: 3.67 95% CI: 1.23–11.0; P for interaction= 0.009). Conversely, higher testosterone excretion (pattern III), was marginally associated with lower (OR: 0.35 95% CI: 0.12–1.00, P for trend= 0.08) poorly differentiated PC (Gleason ≥8). No clear association was observed with pattern II (DHEA; 16α and 16β-OHT). Our results were consistent with the previous evidence which suggests that the C11-oxy backdoor pathway is important for prostatic carcinogenesis. Androgen urine excretion analysis could be useful for PC diagnosis, treatment, and prognosis; however, further studies with a larger number of samples and the urinary determination of 11-ketoandrogens are necessary.