Open Access
ONECUT2 is a druggable driver of luminal to basal breast cancer plasticity
(Sringer, 2024-05-31) Zamora Álvarez, Irene; Gutiérrez Núñez, Miriam; Pascual, Alex; Pajares Villandiego, María Josefa; Barajas Vélez, Miguel Ángel; Perez, Lillian M.; You, Sungyong; Knudsen, Beatrice S.; Freeman, Michael R.; Encío Martínez, Ignacio; Rotinen Díaz, Mirja Sofia; Ciencias de la Salud; Osasun Zientziak; Institute for Multidisciplinary Research in Applied Biology - IMAB; Gobierno de Navarra / Nafarroako Gobernua
Purpose: tumor heterogeneity complicates patient treatment and can be due to transitioning of cancer cells across phenotypic cell states. This process is associated with the acquisition of independence from an oncogenic driver, such as the estrogen receptor (ER) in breast cancer (BC), resulting in tumor progression, therapeutic failure and metastatic spread. The transcription factor ONECUT2 (OC2) has been shown to be a master regulator protein of metastatic castration-resistant prostate cancer (mCRPC) tumors that promotes lineage plasticity to a drug-resistant neuroendocrine (NEPC) phenotype. Here, we investigate the role of OC2 in the dynamic conversion between different molecular subtypes in BC. Methods: we analyze OC2 expression and clinical significance in BC using public databases and immunohistochemical staining. In vitro, we perform RNA-Seq, RT-qPCR and western-blot after OC2 enforced expression. We also assess cellular effects of OC2 silencing and inhibition with a drug-like small molecule in vitro and in vivo. Results: OC2 is highly expressed in a substantial subset of hormone receptor negative human BC tumors and tamoxifen-resistant models, and is associated with poor clinical outcome, lymph node metastasis and heightened clinical stage. OC2 inhibits ER expression and activity, suppresses a gene expression program associated with luminal differentiation and activates a basal-like state at the gene expression level. We also show that OC2 is required for cell growth and survival in metastatic BC models and that it can be targeted with a small molecule inhibitor providing a novel therapeutic strategy for patients with OC2 active tumors. Conclusions: the transcription factor OC2 is a driver of BC heterogeneity and a potential drug target in distinct cell states within the breast tumors.
Open Access
Transcriptional regulation of type 11 17β-hydroxysteroid dehydrogenase expression in prostate cancer cells
(Elsevier, 2011) Rotinen Díaz, Mirja Sofia; Villar Bécares, Joaquín; Celay Leoz, Ion; Serrano Mendioroz, Irantzu; Notario, Vicente; Encío Martínez, Ignacio; Ciencias de la Salud; Osasun Zientziak; Gobierno de Navarra / Nafarroako Gobernua
Type 11 Hydroxysteroid (17-beta) dehydrogenase (HSD17B11) catalyzes the conversion of 5α-androstan-3α,17β-diol into androsterone suggesting that it may play an important role in androgen metabolism. We previously described that overexpression of C/EBPα or C/EBPβ induced HSD17B11 expression in HepG2 cells but this process was not mediated by the CCAAT boxes located within its proximal promoter region. Here, we study HSD17B11 transcriptional regulation in prostate cancer (PC) cells. Transfection experiments showed that the region −107/+18 is sufficient for promoter activity in PC cells. Mutagenesis analysis indicated that Sp1 and C/EBP binding sites found in this region are essential for promoter activity. Additional experiments demonstrated that ectopic expression of Sp1 and C/EBPα upregulated HSD17B11 expression only in PC cell lines. Through DAPA and ChIP assays, specific recruitment of Sp1 and C/EBPα to the HSD17B11 promoter was detected. These results show that HSD17B11 transcription in PC cells is regulated by Sp1 and C/EBPα.
Open Access
ONECUT2 reprograms neuroendocrine fate and is an actionable therapeutic target in small cell lung cancer
(BioMed Central, 2025-06-11) Gutiérrez Núñez, Miriam; Zamora Álvarez, Irene; Iriarte, Raquel; Pajares Villandiego, María Josefa; Yang, Qian; Qian, Chen; Otegui, Nerea; Fernández Irigoyen, Joaquín; Santamaría Martínez, Enrique; Alcala, Nicolas; Sexton-Oates, Alexandra; Fernández-Cuesta, Lynnette; Barajas Vélez, Miguel Ángel; Calvo, Alfonso; Montuenga, Luis M.; Knudsen, Beatrice S.; You, Sungyong; Freeman, Michael R.; Encío Martínez, Ignacio; Rotinen Díaz, Mirja Sofia; Ciencias de la Salud; Osasun Zientziak; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Small cell lung cancer (SCLC) is a highly aggressive malignancy with extremely poor prognosis. SCLC cells exhibit high plasticity and can progress from neuroendocrine (NE) to non-NE phenotypes. This dynamic evolution promotes treatment resistance and relapses, representing a challenge for targeted therapies in this elusive disease. Here we identify the transcription factor ONECUT2 (OC2) as a driver of plasticity in SCLC, leading to non-NE transcriptional states. OC2 is highly expressed in SCLC tumors compared to normal lung tissue and its expression is associated with heightened clinical stage and lymph node metastasis. We show that OC2 is a repressor of ASCL1, the NE master regulator transcription factor. In addition, OC2 upregulates non-NE programs through activation of c-MYC and Notch signaling. We also demonstrate that OC2 is required for growth and survival of SCLC cells and that it can be targeted with a small molecule inhibitor that acts synergistically with the standard combination of cisplatin and etoposide, providing a novel therapeutic strategy for OC2 active SCLC tumors.
Open Access
Changes in gene expression profiling of apoptotic genes in neuroblastoma cell lines upon retinoic acid treatment
(Public Library of Science, 2013) Celay Leoz, Ion; Blanco Luquin, Idoia; Lázcoz Ripoll, Paula; Rotinen Díaz, Mirja Sofia; Castresana, Javier S.; Encío Martínez, Ignacio; Ciencias de la Salud; Osasun Zientziak; Gobierno de Navarra / Nafarroako Gobernua
To determine the effect of retinoic acid (RA) in neuroblastoma we treated RA sensitive neuroblastoma cell lines with 9-cis RA or ATRA for 9 days, or for 5 days followed by absence of RA for another 4 days. Both isomers induced apoptosis and reduced cell density as a result of cell differentiation and/or apoptosis. Flow cytometry revealed that 9-cis RA induced apoptosis more effectively than ATRA. The expression profile of apoptosis and survival pathways was cell line specific and depended on the isomer used.
Open Access
ONECUT2 acts as a lineage plasticity driver in adenocarcinoma as well as neuroendocrine variants of prostate cancer
(Oxford University Press, 2024-06-27) Qian, Chen; Yang, Qian; Rotinen Díaz, Mirja Sofia; Huang, Rongrong; Kim, Hyoyoung; Gallent, Brad; Yan, Yiwu; Cadaneanu, Radu M.; Zhang, Baohui; Kaochar, Salma; Freedland, Stephen J.; Posadas, Edwin M.; Ellis, Leigh; Di Vizio, Dolores; Morrissey, Colm; Nelson, Peter S.; Brady, Lauren; Murali, Ramachandran; Campbell, Moray J.; Yang, Wei; Knudsen, Beatrice S.; Mostaghel, Elahe A.; Ye, Huihui; Garraway, Isla P.; You, Sungyong; Freeman, Michael R.; Ciencias de la Salud; Osasun Zientziak; Institute for Multidisciplinary Research in Applied Biology - IMAB
Androgen receptor- (AR-) indifference is a mechanism of resistance to hormonal therapy in prostate cancer (PC). Here we demonstrate that ONECUT2 (OC2) activates resistance through multiple drivers associated with adenocarcinoma, stem-like and neuroendocrine (NE) variants. Direct OC2 gene targets include the glucocorticoid receptor (GR; NR3C1) and the NE splicing factor SRRM4, which are key drivers of lineage plasticity. Thus, OC2, despite its previously described NEPC driver function, can indirectly activate a portion of the AR cistrome through epigenetic activation of GR. Mechanisms by which OC2 regulates gene expression include promoter binding, enhancement of genome-wide chromatin accessibility, and super-enhancer reprogramming. Pharmacologic inhibition of OC2 suppresses lineage plasticity reprogramming induced by the AR signaling inhibitor enzalutamide. These results demonstrate that OC2 activation promotes a range of drug resistance mechanisms associated with treatment-emergent lineage variation in PC and support enhanced efforts to therapeutically target OC2 as a means of suppressing treatment-resistant disease.
Open Access
Transcriptional regulation of the human type 8 17β-hydroxysteroid dehydrogenase gene by C/EBPβ
(Elsevier, 2007-05-16) Villar Bécares, Joaquín; Celay Leoz, Ion; Alonso Roldán, Marta; Rotinen Díaz, Mirja Sofia; Miguel Vázquez, Carlos de; Migliaccio Vázquez, Marco; Encío Martínez, Ignacio; Ciencias de la Salud; Osasun Zientziak; Gobierno de Navarra / Nafarroako Gobernua
17β-Hydroxysteroid dehydrogenases (17β-HSD) regulate the intracellular concentration of active sex steroid hormones in target tissues. To date, at least 14 different isozymes have been identified. The type 8 17β-hydroxysteroid dehydrogenase (17β-HSD8) selectively catalyzes the conversion of estradiol (E2) to estrone (E1). To map the promoter region and to investigate its regulation, we cloned and fused a 1600 bp DNA fragment upstream of the 17β-HSD8 transcriptional start site to a luciferase reporter gene. After transient transfection in HepG2 cells, this fragment was shown to possess promoter activity. Deletion constructs of the 5′ flanking region of the 17β-HSD8 gene led to the identification of the minimal promoter region within the first 75 bp upstream of the transcriptional start site. This region included two CCAAT boxes and sequences closely resembling the consensus Sp1 and NF-κB motifs. Site directed mutagenesis revealed that the CCAAT boxes were essential for transcription in HepG2. EMSA, supershift and chromatin immunoprecipitation reflected that these sequences were binding sites for C/EBPβ. Furthermore, promoter activity was increased by the co-transfection of a C/EBPβ expression vector, and this transactivation was through both CCAAT boxes. Our studies indicate that C/EBPβ is essential for the transcription of the 17β-HSD8 gene in the liver.
Open Access
Cutting down on lung cancer: Ecliptasaponin A is a novel therapeutic agent
(AME Publishing Company, 2020) Rotinen Díaz, Mirja Sofia; Encío Martínez, Ignacio; Ciencias de la Salud; Osasun Zientziak
This article is a comment of 'Han J, Lv W, Sheng H, et al. Ecliptasaponin A induces apoptosis through the activation of ASK1/JNK pathway and autophagy in human lung cancer cells. Ann Transl Med 2019;7:539'.
Open Access
Actionable driver events in small cell lung cancer
(MDPI, 2024) Gutiérrez Núñez, Miriam; Zamora Álvarez, Irene; Freeman, Michael R.; Encío Martínez, Ignacio; Rotinen Díaz, Mirja Sofia; Ciencias de la Salud; Osasun Zientziak
Small cell lung cancer (SCLC) stands out as the most aggressive form of lung cancer, characterized by an extremely high proliferation rate and a very poor prognosis, with a 5-year survival rate that falls below 7%. Approximately two-thirds of patients receive their diagnosis when the disease has already reached a metastatic or extensive stage, leaving chemotherapy as the remaining first-line treatment option. Other than the recent advances in immunotherapy, which have shown moderate results, SCLC patients cannot yet benefit from any approved targeted therapy, meaning that this cancer remains treated as a uniform entity, disregarding intra- or inter-tumoral heterogeneity. Continuous efforts and technological improvements have enabled the identification of new potential targets that could be used to implement novel therapeutic strategies. In this review, we provide an overview of the most recent approaches for SCLC treatment, providing an extensive compilation of the targeted therapies that are currently under clinical evaluation and inhibitor molecules with promising results in vitro and in vivo.
Open Access
27-hydroxycholesterol impairs plasma membrane lipid raft signaling as evidenced by inhibition of IL6-JAK-STAT3 signaling in prostate cancer cells
(American Association for Cancer Research, 2020-05-01) Dambal, Shweta; Alfaqih, Mahmoud; Sanders, Sergio; Maravilla, Erick; Ramírez-Torres, Adela; Galván, Gloria C.; Reis-Sobreiro, Mariana; Rotinen Díaz, Mirja Sofia; Driver, Lucy M.; Behrove, Matthew. S.; Talisman, Tijana Jovanovic; Yoon, Junhee; You, Sungyong; Turkson, James; Chi, Jen-Tsan; Freeman, Michael R.; Macías, Everardo; Freedland, Stephen J.; Ciencias de la Salud; Osasun Zientziak
We recently reported that restoring the CYP27A1-27hydroxycholesterol axis had antitumor properties. Thus, we sought to determine the mechanism by which 27HC exerts its anti-prostate cancer effects. As cholesterol is a major component of membrane microdomains known as lipid rafts, which localize receptors and facilitate cellular signaling, we hypothesized 27HC would impair lipid rafts, using the IL6-JAK-STAT3 axis as a model given its prominent role in prostate cancer. As revealed by single molecule imaging of DU145 prostate cancer cells, 27HC treatment significantly reduced detected cholesterol density on the plasma membranes. Further, 27HC treatment of constitutively active STAT3 DU145 prostate cancer cells reduced STAT3 activation and slowed tumor growth in vitro and in vivo. 27HC also blocked IL6-mediated STAT3 phosphorylation in nonconstitutively active STAT3 cells. Mechanistically, 27HC reduced STAT3 homodimerization, nuclear translocation, and decreased STAT3 DNA occupancy at target gene promoters. Combined treatment with 27HC and STAT3 targeting molecules had additive and synergistic effects on proliferation and migration, respectively. Hallmark IL6-JAK-STAT gene signatures positively correlated with CYP27A1 gene expression in a large set of human metastatic castrate-resistant prostate cancers and in an aggressive prostate cancer subtype. This suggests STAT3 activation may be a resistance mechanism for aggressive prostate cancers that retain CYP27A1 expression. In summary, our study establishes a key mechanism by which 27HC inhibits prostate cancer by disrupting lipid rafts and blocking STAT3 activation. IMPLICATIONS: Collectively, these data show that modulation of intracellular cholesterol by 27HC can inhibit IL6-JAK-STAT signaling and may synergize with STAT3-targeted compounds.
Open Access
Scaffold attachment factor B1 regulates androgen degradation pathways in prostate cancer
(E-Century Publishing, 2021) Yang, Julie Suan-Wei; Qian, Chen; You, Sungyong; Rotinen Díaz, Mirja Sofia; Posadas, Edwin M.; Freedland, Stephen J.; Di Vizio, Dolores; Kim, Jayoung; Freeman, Michael R.; Ciencias de la Salud; Osasun Zientziak
The nuclear matrix protein Scaffold Attachment Factor B1 (SAFB1, SAFB) can act in prostate cancer (PCa) as an androgen receptor (AR) co-repressor that functions through epigenetic silencing of AR targets, such as prostate specific antigen (PSA, KLK3). Genomic profiling of SAFB1-silenced PCa cells indicated that SAFB1 may play a role in modulating intracrine androgen levels through the regulation of UDP-glucuronosyltransferase (UGT) genes, which inactivate steroid hormones. Gene silencing of SAFB1 resulted in increased levels of free dihydrotesterosterone (DHT), and increased resistance to the AR inhibitor enzalutamide. SAFB1 silencing suppressed expression of the UDP-glucuronosyltransferase family 2 member B15 gene (UGT2B15) and the closely related UGT2B17 gene, which encode proteins that irreversibly inactivate testosterone (T) and DHT. Analysis of human data indicated that genomic loss at the SAFB locus, or down-regulation of expression of the SAFB gene, is associated with aggressive PCa. These findings identify SAFB1 as an important regulator of androgen catabolism in PCa and suggest that loss or inactivation of this protein may promote AR activity by retention of active androgen in tumor cells.