bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from ID1 Promotes Breast Cancer Metastasis by S100A9 Regulation
Authors: Gumireddy Kiranmai , Li Anping , Kossenkov Andrew V. , Cai Kathy Q. , Liu Qin , Yan Jinchun , Xu Hua , Showe Louise , Zhang Lin , Huang Qihong
Published: April 2023

Abstract
Metastasis is a major factor responsible for mortality in patients with breast cancer. Inhibitor of DNA binding 1 (Id1) has been shown to play an important role in cell differentiation, tumor angiogenesis, cell invasion, and metastasis. Despite the data establishing Id1 as a critical factor for lung metastasis in breast cancer, the pathways and molecular mechanisms of Id1 functions in metastasis remain to be defined. Here, we show that Id1 interacts with TFAP2A to suppress S100A9 expression. We show that expression of Id1 and S100A9 is inversely correlated in both breast cancer cell lines and clinical samples. We also show that the migratory and invasive phenotypes in vitro and metastasis in vivo induced by Id1 expression are rescued by reestablishment of S100A9 expression. S100A9 also suppresses the expression of known metastasis-promoting factor RhoC activated by Id1 expression. Our results suggest that Id1 promotes breast cancer metastasis by the suppression of S100A9 expression.

Implications: Novel pathways by Id1 regulation in metastasis. Mol Cancer Res; 12(9); 1334–43. ©2014 AACR.
Data from RAD51 and BRCA2 Enhance Oncolytic Adenovirus Type 5 Activity in Ovarian Cancer
Authors: Tookman Laura A. , Browne Ashley K. , Connell Claire M. , Bridge Gemma , Ingemarsdotter Carin K. , Dowson Suzanne , Shibata Atsushi , Lockley Michelle , Martin Sarah A. , McNeish Iain A.
Published: April 2023

Abstract
Homologous recombination (HR) function is critically important in high-grade serous ovarian cancer (HGSOC). HGSOC with intact HR has a worse prognosis and is less likely to respond to platinum chemotherapy and PARP inhibitors. Oncolytic adenovirus, a novel therapy for human malignancies, stimulates a potent DNA damage response that influences overall antitumor activity. Here, the importance of HR was investigated by determining the efficacy of adenovirus type 5 (Ad5) vectors in ovarian cancer. Using matched BRCA2-mutant and wild-type HGSOC cells, it was demonstrated that intact HR function promotes viral DNA replication and augments overall efficacy, without influencing viral DNA processing. These data were confirmed in a wider panel of HR competent and defective ovarian cancer lines. Mechanistically, both BRCA2 and RAD51 localize to viral replication centers within the infected cell nucleus and that RAD51 localization occurs independently of BRCA2. In addition, a direct interaction was identified between RAD51 and adenovirus E2 DNA binding protein. Finally, using functional assays of HR competence, despite inducing degradation of MRE11, Ad5 infection does not alter cellular ability to repair DNA double-strand break damage via HR. These data reveal that Ad5 redistributes critical HR components to viral replication centers and enhances cytotoxicity.

Implications: Oncolytic adenoviral therapy may be most clinically relevant in tumors with intact HR function. Mol Cancer Res; 14(1); 44–55. ©2015 AACR.
Data from Triapine Disrupts CtIP-Mediated Homologous Recombination Repair and Sensitizes Ovarian Cancer Cells to PARP and Topoisomerase Inhibitors
Authors: Lin Z. Ping , Ratner Elena S. , Whicker Margaret E. , Lee Yashang , Sartorelli Alan C.
Published: April 2023

Abstract
PARP inhibitors exploit synthetic lethality to target epithelial ovarian cancer (EOC) with hereditary BRCA mutations and defects in homologous recombination repair (HRR). However, such an approach is limited to a small subset of EOC patients and compromised by restored HRR due to secondary mutations in BRCA genes. Here, it was demonstrated that triapine, a small-molecule inhibitor of ribonucleotide reductase, enhances the sensitivity of BRCA wild-type EOC cells to the PARP inhibitor olaparib and the topoisomerase II inhibitor etoposide. Triapine abolishes olaparib-induced BRCA1 and Rad51 foci, and disrupts the BRCA1 interaction with the Mre11–Rad50–Nbs1 (MRN) complex in BRCA1 wild-type EOC cells. It has been shown that phosphorylation of CtIP (RBBP8) is required for the interaction with BRCA1 and with MRN to promote DNA double-strand break (DSB) resection during S and G2 phases of the cell cycle. Mechanistic studies within reveal that triapine inhibits cyclin-dependent kinase (CDK) activity and blocks olaparib-induced CtIP phosphorylation through Chk1 activation. Furthermore, triapine abrogates etoposide-induced CtIP phosphorylation and DSB resection as evidenced by marked attenuation of RPA32 phosphorylation. Concurrently, triapine obliterates etoposide-induced BRCA1 foci and sensitizes BRCA1 wild-type EOC cells to etoposide. Using a GFP-based HRR assay, it was determined that triapine suppresses HRR activity induced by an I-SceI–generated DSB. These results suggest that triapine augments the sensitivity of BRCA wild-type EOC cells to drug-induced DSBs by disrupting CtIP-mediated HRR.

Implications: These findings provide a strong rationale for combining triapine with PARP or topoisomerase inhibitors to target HRR-proficient EOC cells. Mol Cancer Res; 12(3); 381–93. ©2014 AACR.
Data from MUC1-C Represses the Crumbs Complex Polarity Factor CRB3 and Downregulates the Hippo Pathway
Authors: Alam Maroof , Bouillez Audrey , Tagde Ashujit , Ahmad Rehan , Rajabi Hasan , Maeda Takahiro , Hiraki Masayuki , Suzuki Yozo , Kufe Donald
Published: April 2023

Abstract
Apical–basal polarity and epithelial integrity are maintained in part by the Crumbs (CRB) complex. The C-‐terminal subunit of MUC1 (MUC1-C) is a transmembrane protein that is expressed at the apical border of normal epithelial cells and aberrantly at high levels over the entire surface of their transformed counterparts. However, it is not known whether MUC1-C contributes to this loss of polarity that is characteristic of carcinoma cells. Here it is demonstrated that MUC1-C downregulates expression of the Crumbs complex CRB3 protein in triple-negative breast cancer (TNBC) cells. MUC1-C associates with ZEB1 on the CRB3 promoter and represses CRB3 transcription. Notably, CRB3 activates the core kinase cassette of the Hippo pathway, which includes LATS1 and LATS2. In this context, targeting MUC1-C was associated with increased phosphorylation of LATS1, consistent with activation of the Hippo pathway, which is critical for regulating cell contact, tissue repair, proliferation, and apoptosis. Also shown is that MUC1-C‐-mediated suppression of CRB3 and the Hippo pathway is associated with dephosphorylation and activation of the oncogenic YAP protein. In turn, MUC1-C interacts with YAP, promotes formation of YAP/β-catenin complexes, and induces the WNT target gene MYC. These data support a previously unrecognized pathway in which targeting MUC1-C in TNBC cells (i) induces CRB3 expression, (ii) activates the CRB3-driven Hippo pathway, (iii) inactivates YAP, and thereby (iv) suppresses YAP/β-catenin–mediated induction of MYC expression.

Implications: These findings demonstrate a previously unrecognized role for the MUC1-C oncoprotein in the regulation of polarity and the Hippo pathway in breast cancer. Mol Cancer Res; 14(12); 1266–76. ©2016 AACR.
Data from Oncogenic KRAS Targets MUC16/CA125 in Pancreatic Ductal Adenocarcinoma
Authors: Liang Chen , Qin Yi , Zhang Bo , Ji Shunrong , Shi Si , Xu Wenyan , Liu Jiang , Xiang Jinfeng , Liang Dingkong , Hu Qiangsheng , Ni Quanxing , Xu Jin , Yu Xianjun
Published: April 2023

Abstract
Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with the 5-year survival rate less than 6%. Previous results indicated that serum levels of CA125 (encoded by MUC16) could be used to predict which groups of pancreatic cancer patients may benefit from surgery. However, the underlying mechanism remains elusive. Herein, using the Cancer Genome Atlas and clinicopathologic data obtained from our center, we demonstrate that high CA125 serum levels and expression levels of MUC16 are predictive of poor prognosis. MUC16 is also validated as a downstream target of KRAS, and their expression strongly correlated with each other in vitro and in vivo. Mechanistically, the KRAS/ERK axis induced upregulation of MUC16 and shedding of CA125 via its effector c-Myc in SW1990 and PANC-1 pancreatic cancer cells. Notably, proto-oncogene c-Myc could bind to the promoter of MUC16 and transcriptionally activate its expression. Taken together, these data establish CA125 as a prognostic marker for pancreatic cancer, and mechanistic studies uncovered the KRAS/c-Myc axis as a driving factor for upregulation of MUC16.

Implications: The current study uncovers the contribution of oncogenic KRAS to serum marker CA125 production through a mechanism that involves the ERK/c-Myc axis. Mol Cancer Res; 15(2); 201–12. ©2016 AACR.
Data from Constitutive Activation of DNA Damage Checkpoint Signaling Contributes to Mutant p53 Accumulation via Modulation of p53 Ubiquitination
Authors: Frum Rebecca A. , Love Ian M. , Damle Priyadarshan K. , Mukhopadhyay Nitai D. , Palit Deb Swati , Deb Sumitra , Grossman Steven R.
Published: April 2023

Abstract
Many mutant p53 proteins exhibit an abnormally long half-life and overall increased abundance compared with wild-type p53 in tumors, contributing to mutant p53's gain-of-function oncogenic properties. Here, a novel mechanism is revealed for the maintenance of mutant p53 abundance in cancer that is dependent on DNA damage checkpoint activation. High-level mutant p53 expression in lung cancer cells was associated with preferential p53 monoubiquitination versus polyubiquitination, suggesting a role for the ubiquitin/proteasome system in regulation of mutant p53 abundance in cancer cells. Interestingly, mutant p53 ubiquitination status was regulated by ataxia–telangectasia mutated (ATM) activation and downstream phosphorylation of mutant p53 (serine 15), both in resting and in genotoxin-treated lung cancer cells. Specifically, either inhibition of ATM with caffeine or mutation of p53 (serine 15 to alanine) restored MDM2-dependent polyubiquitination of otherwise monoubiquitinated mutant p53. Caffeine treatment rescued MDM2-dependent proteasome degradation of mutant p53 in cells exhibiting active DNA damage signaling, and ATM knockdown phenocopied the caffeine effect. Importantly, in cells analyzed individually by flow cytometry, p53 levels were highest in cells exhibiting the greatest levels of DNA damage response, and interference with DNA damage signaling preferentially decreased the relative percentage of cells in a population with the highest levels of mutant p53. These data demonstrate that active DNA damage signaling contributes to high levels of mutant p53 via modulation of ubiquitin/proteasome activity toward p53.

Implication: The ability of DNA damage checkpoint signaling to mediate accumulation of mutant p53 suggests that targeting this signaling pathway may provide therapeutic gain. Mol Cancer Res; 14(5); 423–36. ©2016 AACR.
Data from Extracellular Fatty Acids Are the Major Contributor to Lipid Synthesis in Prostate Cancer
Authors: Balaban Seher , Nassar Zeyad D. , Zhang Alison Y. , Hosseini-Beheshti Elham , Centenera Margaret M. , Schreuder Mark , Lin Hui-Ming , Aishah Atqiya , Varney Bianca , Liu-Fu Frank , Lee Lisa S. , Nagarajan Shilpa R. , Shearer Robert F. , Hardie Rae-Anne , Raftopulos Nikki L. , Kakani Meghna S. , Saunders Darren N. , Holst Jeff , Horvath Lisa G. , Butler Lisa M. , Hoy Andrew J.
Published: April 2023

Abstract
Prostate cancer cells exhibit altered cellular metabolism but, notably, not the hallmarks of Warburg metabolism. Prostate cancer cells exhibit increased de novo synthesis of fatty acids (FA); however, little is known about how extracellular FAs, such as those in the circulation, may support prostate cancer progression. Here, we show that increasing FA availability increased intracellular triacylglycerol content in cultured patient-derived tumor explants, LNCaP and C4-2B spheroids, a range of prostate cancer cells (LNCaP, C4-2B, 22Rv1, PC-3), and prostate epithelial cells (PNT1). Extracellular FAs are the major source (∼83%) of carbons to the total lipid pool in all cell lines, compared with glucose (∼13%) and glutamine (∼4%), and FA oxidation rates are greater in prostate cancer cells compared with PNT1 cells, which preferentially partitioned extracellular FAs into triacylglycerols. Because of the higher rates of FA oxidation in C4-2B cells, cells remained viable when challenged by the addition of palmitate to culture media and inhibition of mitochondrial FA oxidation sensitized C4-2B cells to palmitate-induced apoptosis. Whereas in PC-3 cells, palmitate induced apoptosis, which was prevented by pretreatment of PC-3 cells with FAs, and this protective effect required DGAT-1–mediated triacylglycerol synthesis. These outcomes highlight for the first-time heterogeneity of lipid metabolism in prostate cancer cells and the potential influence that obesity-associated dyslipidemia or host circulating has on prostate cancer progression.
Implications:
Extracellular-derived FAs are primary building blocks for complex lipids and heterogeneity in FA metabolism exists in prostate cancer that can influence tumor cell behavior.
Data from Novel YAP1 Activator, Identified by Transcription-Based Functional Screen, Limits Multiple Myeloma Growth
Authors: Maruyama Junichi , Inami Kazutoshi , Michishita Fumiyoshi , Jiang Xinliang , Iwasa Hiroaki , Nakagawa Kentaro , Ishigami-Yuasa Mari , Kagechika Hiroyuki , Miyamura Norio , Hirayama Jun , Nishina Hiroshi , Nogawa Daichi , Yamamoto Kouhei , Hata Yutaka
Published: April 2023

Abstract
Yes-associated protein 1 (YAP1) interacts with numerous transcription factors, including TEA-domain family proteins (TEAD) and p73. YAP1 is negatively regulated by the tumor suppressor Hippo pathway. In human cancers, the deregulation of the Hippo pathway and YAP1 gene amplification lead to the activation of YAP1, which induces epithelial–mesenchymal transition (EMT) and drug resistance. YAP1 inhibitors are expected to be useful in cancer therapy. On the other hand, in certain cancers, YAP1 upregulates p73-dependent gene transcription and behaves as a tumor suppressor. Moreover, as YAP1 regulates self-renewal and differentiation of tissue stem cells and plays an important role in tissue homeostasis, YAP1 activators may contribute to the regenerative medicine. With this in our mind, we screened for YAP1 activators by using human retinal pigment epithelial ARPE-19 cells expressing the TEAD-responsive fluorescence reporter under the coexpression of YAP1. From an extensive chemical compound library (n = 18,606) 47 candidate YAP1 activators were identified. These compounds were characterized to determine whether this assay provides bona fide YAP1 activators. Importantly, one YAP1 activator was effective against the human multiple myeloma IM-9 cells and chronic myeloid leukemia K562 cells.

Implications: YAP1 activation limits growth, induces apoptosis, and may be useful at suppressing hematological cancers. Mol Cancer Res; 16(2); 197–211. ©2017 AACR.
Data from ELF4 Is a Target of miR-124 and Promotes Neuroblastoma Proliferation and Undifferentiated State
Authors: Kosti Adam , Du Liqin , Shivram Haridha , Qiao Mei , Burns Suzanne , Garcia Juan Gabriel , Pertsemlidis Alexander , Iyer Vishwanath R. , Kokovay Erzsebet , Penalva Luiz O.F.
Published: April 2023

Abstract
13-Cis-retinoic acid (RA) is typically used in postremission maintenance therapy in patients with neuroblastoma. However, side effects and recurrence are often observed. We investigated the use of miRNAs as a strategy to replace RA as promoters of differentiation. miR-124 was identified as the top candidate in a functional screen. Genomic target analysis indicated that repression of a network of transcription factors (TF) could be mediating most of miR-124's effect in driving differentiation. To advance miR-124 mimic use in therapy and better define its mechanism of action, a high-throughput siRNA morphologic screen focusing on its TF targets was conducted and ELF4 was identified as a leading candidate for miR-124 repression. By altering its expression levels, we showed that ELF4 maintains neuroblastoma in an undifferentiated state and promotes proliferation. Moreover, ELF4 transgenic expression was able to counteract the neurogenic effect of miR-124 in neuroblastoma cells. With RNA sequencing, we established the main role of ELF4 to be regulation of cell-cycle progression, specifically through the DREAM complex. Interestingly, several cell-cycle genes activated by ELF4 are repressed by miR-124, suggesting that they might form a TF–miRNA regulatory loop. Finally, we showed that high ELF4 expression is often observed in neuroblastomas and is associated with poor survival.
Implications:
miR-124 induces neuroblastoma differentiation partially through the downregulation of TF ELF4, which drives neuroblastoma proliferation and its undifferentiated phenotype.
Data from Functional Loss of ATRX and TERC Activates Alternative Lengthening of Telomeres (ALT) in LAPC4 Prostate Cancer Cells
Authors: Graham Mindy K. , Kim Jiyoung , Da Joseph , Brosnan-Cashman Jacqueline A. , Rizzo Anthony , Baena Del Valle Javier A. , Chia Lionel , Rubenstein Michael , Davis Christine , Zheng Qizhi , Cope Leslie , Considine Michael , Haffner Michael C. , De Marzo Angelo M. , Meeker Alan K. , Heaphy Christopher M.
Published: April 2023

Abstract
A key hallmark of cancer, unlimited replication, requires cancer cells to evade both replicative senescence and potentially lethal chromosomal instability induced by telomere dysfunction. The majority of cancers overcome these critical barriers by upregulating telomerase, a telomere-specific reverse transcriptase. However, a subset of cancers maintains telomere lengths by the telomerase-independent Alternative Lengthening of Telomeres (ALT) pathway. The presence of ALT is strongly associated with recurrent cancer-specific somatic inactivating mutations in the ATRX-DAXX chromatin-remodeling complex. Here, we generate an ALT-positive adenocarcinoma cell line following functional inactivation of ATRX and telomerase in a telomerase-positive adenocarcinoma cell line. Inactivating mutations in ATRX were introduced using CRISPR-cas9 nickase into two prostate cancer cell lines, LAPC-4 (derived from a lymph node metastasis) and CWR22Rv1 (sourced from a xenograft established from a primary prostate cancer). In LAPC-4, but not CWR22Rv1, abolishing ATRX was sufficient to induce multiple ALT-associated hallmarks, including the presence of ALT-associated promyelocytic leukemia bodies (APB), extrachromosomal telomere C-circles, and dramatic telomere length heterogeneity. However, telomerase activity was still present in these ATRXKO cells. Telomerase activity was subsequently crippled in these LAPC-4 ATRXKO cells by introducing mutations in the TERC locus, the essential RNA component of telomerase. These LAPC-4 ATRXKO TERCmut cells continued to proliferate long-term and retained ALT-associated hallmarks, thereby demonstrating their reliance on the ALT mechanism for telomere maintenance.
Implications:
These prostate cancer cell line models provide a unique system to explore the distinct molecular alterations that occur upon induction of ALT, and may be useful tools to screen for ALT-specific therapies.
Data from ZEB1 Collaborates with ELK3 to Repress E-Cadherin Expression in Triple-Negative Breast Cancer Cells
Authors: Cho Hyeon-Ju , Oh Nuri , Park Ji-Hoon , Kim Kwang-Soo , Kim Hyung-Keun , Lee Eunbyeol , Hwang Sohyun , Kim Seong-Jin , Park Kyung-Soon
Published: April 2023

Abstract
ZEB1 has intrinsic oncogenic functions that control the epithelial-to-mesenchymal transition (EMT) of cancer cells, impacting tumorigenesis from its earliest stages. By integrating microenvironment signals and being implicated in feedback regulatory loops, ZEB1 appears to be a central switch that determines EMT and metastasis of cancer cells. Here, we found that ZEB1 collaborates with ELK3, a ternary complex factor belonging to the ETS family, to repress E-cadherin expression. ZEB1 functions as a transcriptional activator of ELK3. We first identified that ELK3 and ZEB1 have a positively correlated expression in breast cancer cells by using multiple databases for correlation analysis. Molecular analysis revealed that ZEB1 functions as a transcriptional activator of ELK3 expression. GST pull-down assay and coimmunoprecipitation analysis of wild-type or domain deletion mutants of ZEB1 and ELK3 showed that these 2 proteins directly bound each other. Furthermore, we demonstrated that ZEB1 and ELK3 collaborate to repress the expression of E-cadherin, a representative protein that initiates EMT. Our finding suggested that ELK3 is a novel factor of the ZEB1/E-cadherin axis in triple-negative breast cancer cells.
Implications:
ELK3 is a novel factor in the ZEB1/E-cadherin axis and ZEB1 has a dual role in ELK3 as a transcriptional activator and as a collaborator to repress E-cadherin expression in triple-negative breast cancer cells.
Data from Recurrent Patterns of Protein Expression Signatures in Pediatric Acute Lymphoblastic Leukemia: Recognition and Therapeutic Guidance
Authors: Hoff Fieke W. , Hu Chenyue W. , Qiu Yihua , Ligeralde Andrew , Yoo Suk-Young , Scheurer Michael E. , de Bont Eveline S.J.M. , Qutub Amina A. , Kornblau Steven M. , Horton Terzah M.
Published: April 2023

Abstract
Pediatric acute lymphoblastic leukemia (ALL) is the most common pediatric malignancy, and the second leading cause of pediatric cancer–related death in developed countries. While the cure rate for newly diagnosed ALL is excellent, the genetic heterogeneity and chemoresistance of leukemia cells at relapse makes individualized curative treatment plans difficult. We hypothesize that genetic events would coalesce into a finite number of protein signatures that could guide the design of individualized therapy. Custom reverse-phase protein arrays were produced from pediatric ALL (n = 73) and normal CD34+ (n = 10) samples with 194 validated antibodies. Proteins were allocated into 31 protein functional groups (PFG) to analyze them in the context of other proteins, based on known associations from the literature. The optimal number of protein clusters was determined for each PFG. Protein networks showed distinct transition states, revealing “normal-like” and “leukemia-specific” protein patterns. Block clustering identified strong correlation between various protein clusters that formed 10 protein constellations. Patients that expressed similar recurrent combinations of constellations comprised 7 distinct signatures, correlating with risk stratification, cytogenetics, and laboratory features. Most constellations and signatures were specific for T-cell ALL or pre-B-cell ALL; however, some constellations showed significant overlap. Several signatures were associated with Hispanic ethnicity, suggesting that ethnic pathophysiologic differences likely exist. In addition, some constellations were enriched for “normal-like” protein clusters, whereas others had exclusively “leukemia-specific” patterns.

Implications: Recognition of proteins that have universally altered expression, together with proteins that are specific for a given signature, suggests targets for directed combinatorial inhibition or replacement to enable personalized therapy. Mol Cancer Res; 16(8); 1263–74. ©2018 AACR.

See related article by Hoff et al., p. 1275
Data from MCL1 and DEDD Promote Urothelial Carcinoma Progression
Authors: Hong Andrew L. , Guerriero Jennifer L. , Doshi Mihir B. , Kynnap Bryan D. , Kim Won Jun , Schinzel Anna C. , Modiste Rebecca , Schlauch Amy J. , Adam Rosalyn M. , Kwiatkowski David J. , Beroukhim Rameen , Letai Anthony , Rosenberg Jonathan E. , Hahn William C.
Published: April 2023

Abstract
Focal amplification of chromosome 1q23.3 in patients with advanced primary or relapsed urothelial carcinomas is associated with poor survival. We interrogated chromosome 1q23.3 and the nearby focal amplicon 1q21.3, as both are associated with increased lymph node disease in patients with urothelial carcinoma. Specifically, we assessed whether the oncogene MCL1 that resides in 1q21.3 and the genes that reside in the 1q23.3 amplicon were required for the proliferation or survival of urothelial carcinoma. We observed that suppressing MCL1 or the death effector domain–containing protein (DEDD) in the cells that harbor amplifications of 1q21.3 or 1q23.3, respectively, inhibited cell proliferation. We also found that overexpression of MCL1 or DEDD increased anchorage independence growth in vitro and increased experimental metastasis in vivo in the nonamplified urothelial carcinoma cell line, RT112. The expression of MCL1 confers resistance to a range of apoptosis inducers, while the expression of DEDD led to resistance to TNFα-induced apoptosis. These observations identify MCL1 and DEDD as genes that contribute to aggressive urothelial carcinoma.
Implications:
These studies identify MCL1 and DEDD as genes that contribute to aggressive urothelial carcinomas.
Data from Potent Antineoplastic Effects of Combined PI3Kα–MNK Inhibition in Medulloblastoma
Authors: Eckerdt Frank , Bell Jonathan B. , Beauchamp Elspeth M. , Clymer Jessica , Blyth Gavin T. , Kosciuczuk Ewa M. , Ma Quanhong , Chen David Z. , Horbinski Craig , Goldman Stewart , Munshi Hidayatullah G. , Hashizume Rintaro , Platanias Leonidas C.
Published: April 2023

Abstract
Medulloblastoma is a highly malignant pediatric brain tumor associated with poor outcome. Developing treatments that target the cancer stem cell (CSC) population in medulloblastoma are important to prevent tumor relapse and induce long-lasting clinical responses. We utilized medulloblastoma neurospheres that display CSC characteristics and found activation of the PI3K/AKT pathway in sphere-forming cells. Of all class IA PI3Ks, only the PI3Kα isoform was required for sphere formation by medulloblastoma cells. Knockdown of p110α, but not p110β or p110δ, significantly disrupted cancer stem cell frequencies as determined by extreme limiting dilution analysis (ELDA), indicating an essential role for the PI3Kα catalytic isoform in medulloblastoma CSCs. Importantly, pharmacologic inhibition of the MAPK-interacting kinase (MNK) enhanced the antineoplastic effects of targeted PI3Kα inhibition in medulloblastoma. This indicates that MNK signaling promotes survival in medulloblastoma, suggesting dual PI3Kα and MNK inhibition may provide a novel approach to target and eliminate medulloblastoma CSCs. We also observed a significant reduction in tumor formation in subcutaneous and intracranial mouse xenograft models, which further suggests that this combinatorial approach may represent an efficient therapeutic strategy for medulloblastoma.
Implications:
These findings raise the possibility of a unique therapeutic approach for medulloblastoma, involving MNK targeting to sensitize medulloblastoma CSCs to PI3Kα inhibition.
Data from A Human Genome-Wide RNAi Screen Reveals Diverse Modulators that Mediate IRE1α–XBP1 Activation
Authors: Yang Zhifen , Zhang Jing , Jiang Dadi , Khatri Purvesh , Solow-Cordero David E. , Toesca Diego A.S. , Koumenis Constantinos , Denko Nicholas C. , Giaccia Amato J. , Le Quynh-Thu , Koong Albert C.
Published: April 2023

Abstract
Activation of the unfolded protein response (UPR) signaling pathways is linked to multiple human diseases, including cancer. The inositol-requiring kinase 1α (IRE1α)–X-box binding protein 1 (XBP1) pathway is the most evolutionarily conserved of the three major signaling branches of the UPR. Here, we performed a genome-wide siRNA screen to obtain a systematic assessment of genes integrated in the IRE1α–XBP1 axis. We monitored the expression of an XBP1-luciferase chimeric protein in which luciferase was fused in-frame with the spliced (active) form of XBP1. Using cells expressing this reporter construct, we identified 162 genes for which siRNA inhibition resulted in alteration in XBP1 splicing. These genes express diverse types of proteins modulating a wide range of cellular processes. Pathway analysis identified a set of genes implicated in the pathogenesis of breast cancer. Several genes, including BCL10, GCLM, and IGF1R, correlated with worse relapse-free survival (RFS) in an analysis of patients with triple-negative breast cancer (TNBC). However, in this cohort of 1,908 patients, only high GCLM expression correlated with worse RFS in both TNBC and non-TNBC patients. Altogether, our study revealed unidentified roles of novel pathways regulating the UPR, and these findings may serve as a paradigm for exploring novel therapeutic opportunities based on modulating the UPR.

Implications: Genome-wide RNAi screen identifies novel genes/pathways that modulate IRE1α–XBP1 signaling in human tumor cells and leads to the development of improved therapeutic approaches targeting the UPR.

Visual Overview: http://mcr.aacrjournals.org/content/molcanres/16/5/745/F1.large.jpg. Mol Cancer Res; 16(5); 745–53. ©2018 AACR.
Data from Identification of Genes Regulating Breast Cancer Dormancy in 3D Bone Endosteal Niche Cultures
Authors: McGrath Julie , Panzica Louis , Ransom Ryan , Withers Henry G. , Gelman Irwin H.
Published: April 2023

Abstract
Tumor cell dormancy is a significant clinical problem in breast cancer. We used a three-dimensional (3D) in vitro model of the endosteal bone niche (EN), consisting of endothelial, bone marrow stromal cells, and fetal osteoblasts in a 3D collagen matrix (GELFOAM), to identify genes required for dormancy. Human triple-negative MDA-MB-231 breast cancer cells, but not the bone-tropic metastatic variant, BoM1833, established dormancy in 3D-EN cultures in a p38-MAPK–dependent manner, whereas both cell types proliferated on two-dimensional (2D) plastic or in 3D collagen alone. “Dormancy-reactivation suppressor genes” (DRSG) were identified using a genomic short hairpin RNA (shRNA) screen in MDA-MB-231 cells for gene knockdowns that induced proliferation in the 3D-EN. DRSG candidates enriched for genes controlling stem cell biology, neurogenesis, MYC targets, ribosomal structure, and translational control. Several potential DRSG were confirmed using independent shRNAs, including BHLHE41, HBP1, and WNT3. Overexpression of the WNT3/a antagonists secreted frizzled-related protein 2 or 4 (SFRP2/4) and induced MDA-MB-231 proliferation in the EN. In contrast, overexpression of SFRP3, known not to antagonize WNT3/a, did not induce proliferation. Decreased WNT3 or BHLHE41 expression was found in clinical breast cancer metastases compared with primary-site lesions, and the loss of WNT3 or BHLHE41 or gain of SFRP1, 2, and 4 in the context of TP53 loss/mutation correlated with decreased progression-free and overall survival.
Implications:
These data describe several novel, potentially targetable pathways controlling breast cancer dormancy in the EN.
Data from Establishment and Characterization of Four Novel Thyroid Cancer Cell Lines and PDX Models Expressing the RET/PTC1 Rearrangement, BRAFV600E, or RASQ61R as Drivers
Authors: Schweppe Rebecca E. , Pozdeyev Nikita , Pike Laura A. , Korch Christopher , Zhou Qiong , Sams Sharon B. , Sharma Vibha , Pugazhenthi Umarani , Raeburn Christopher , Albuja-Cruz Maria B. , Reigan Philip , LaBarbera Daniel V. , Landa Iñigo , Knauf Jeffrey A. , Fagin James A. , Haugen Bryan R.
Published: April 2023

Abstract
Cancer cell lines are critical models to study tumor progression and response to therapy. In 2008, we showed that approximately 50% of thyroid cancer cell lines were redundant or not of thyroid cancer origin. We therefore generated new authenticated thyroid cancer cell lines and patient-derived xenograft (PDX) models using in vitro and feeder cell approaches, and characterized these models in vitro and in vivo. We developed four thyroid cancer cell lines, two derived from 2 different patients with papillary thyroid cancer (PTC) pleural effusions, CUTC5, and CUTC48; one derived from a patient with anaplastic thyroid cancer (ATC), CUTC60; and one derived from a patient with follicular thyroid cancer (FTC), CUTC61. One PDX model (CUTC60-PDX) was also developed. Short tandem repeat (STR) genotyping showed that each cell line and PDX is unique and match the original patient tissue. The CUTC5 and CUTC60 cells harbor the BRAF (V600E) mutation, the CUTC48 cell line expresses the RET/PTC1 rearrangement, and the CUTC61 cells have the HRAS (Q61R) mutation. Moderate to high levels of PAX8 and variable levels of NKX2-1 were detected in each cell line and PDX. The CUTC5 and CUTC60 cell lines form tumors in orthotopic and flank xenograft mouse models.
Implications:
 We have developed the second RET/PTC1-expressing PTC-derived cell line in existence, which is a major advance in studying RET signaling. We have further linked all cell lines to the originating patients, providing a set of novel, authenticated thyroid cancer cell lines and PDX models to study advanced thyroid cancer.
Data from ONC201 Targets AR and AR-V7 Signaling, Reduces PSA, and Synergizes with Everolimus in Prostate Cancer
Authors: Lev Avital , Lulla Amriti R. , Ross Brian C. , Ralff Marie D. , Makhov Petr B. , Dicker David T. , El-Deiry Wafik S.
Published: April 2023

Abstract
Androgen receptor (AR) signaling plays a key role in prostate cancer progression, and androgen deprivation therapy (ADT) is a mainstay clinical treatment regimen for patients with advanced disease. Unfortunately, most prostate cancers eventually become androgen-independent and resistant to ADT with patients progressing to metastatic castration-resistant prostate cancer (mCRPC). Constitutively activated AR variants (AR-V) have emerged as mediators of resistance to AR-targeted therapy and the progression of mCRPC, and they represent an important therapeutic target. Out of at least 15 AR-Vs described thus far, AR-V7 is the most abundant, and its expression correlates with ADT resistance. ONC201/TIC10 is the founding member of the imipridone class of small molecules and has shown anticancer activity in a broad range of tumor types. ONC201 is currently being tested in phase I/II clinical trials for advanced solid tumors, including mCRPC, and hematologic malignancies. There has been promising activity observed in patients in early clinical testing. This study demonstrates preclinical single-agent efficacy of ONC201 using in vitro and in vivo models of prostate cancer. ONC201 has potent antiproliferative and proapoptotic effects in both castration-resistant and -sensitive prostate cancer cells. Furthermore, the data demonstrate that ONC201 downregulates the expression of key drivers of prostate cancer such as AR-V7 and downstream target genes including the clinically used biomarker PSA (KLK3). Finally, the data also provide a preclinical rationale for combination of ONC201 with approved therapeutics for prostate cancer such as enzalutamide, everolimus (mTOR inhibitor), or docetaxel.

Implications: The preclinical efficacy of ONC201 as a single agent or in combination, in hormone-sensitive or castration-resistant prostate cancer, suggests the potential for immediate clinical translation. Mol Cancer Res; 16(5); 754–66. ©2018 AACR.
Data from Foxo-dependent Par-4 Upregulation Prevents Long-term Survival of Residual Cells Following PI3K–Akt Inhibition
Authors: Damrauer Jeffrey S. , Phelps Stephanie N. , Amuchastegui Katie , Lupo Ryan , Mabe Nathaniel W. , Walens Andrea , Kroger Benjamin R. , Alvarez James V.
Published: April 2023

Abstract
Tumor recurrence is a leading cause of death and is thought to arise from a population of residual cells that survive treatment. These residual cancer cells can persist, locally or at distant sites, for years or decades. Therefore, understanding the pathways that regulate residual cancer cell survival may suggest opportunities for targeting these cells to prevent recurrence. Previously, it was observed that the proapoptotic protein (PAWR/Par-4) negatively regulates residual cell survival and recurrence in mice and humans. However, the mechanistic underpinnings on how Par-4 expression is regulated are unclear. Here, it is demonstrated that Par-4 is transcriptionally upregulated following treatment with multiple drugs targeting the PI3K–Akt–mTOR signaling pathway, and identify the Forkhead family of transcription factors as mediators of this upregulation. Mechanistically, Foxo3a directly binds to the Par-4 promoter and activates its transcription following inhibition of the PI3K–Akt pathway. This Foxo-dependent Par-4 upregulation limits the long-term survival of residual cells following treatment with therapeutics that target the PI3K–Akt pathway. Taken together, these results indicate that residual breast cancer tumor cell survival and recurrence requires circumventing Foxo-driven Par-4 upregulation and suggest that approaches to enforce Par-4 expression may prevent residual cell survival and recurrence. Mol Cancer Res; 16(4); 599–609. ©2018 AACR.
Data from Targeted AKT Inhibition in Prostate Cancer Cells and Spheroids Reduces Aerobic Glycolysis and Generation of Hyperpolarized [1-13C] Lactate
Authors: Tee Sui Seng , Suster Izabela , Truong Steven , Jeong Sangmoo , Eskandari Roozbeh , DiGialleonardo Valentina , Alvarez Julio A. , Aldeborgh Hannah N. , Keshari Kayvan R.
Published: April 2023

Abstract
The PI3K/AKT/mTOR (PAM) signaling pathway is frequently mutated in prostate cancer. Specific AKT inhibitors are now in advanced clinical trials, and this study investigates the effect of MK2206, a non–ATP-competitive inhibitor, on the cellular metabolism of prostate cancer cells. We observed a reduction in cell motility and aerobic glycolysis in prostate cancer cells with treatment. These changes were not accompanied by a reduction in the ratio of high-energy phosphates or a change in total protein levels of enzymes and transporters involved in glycolysis. However, a decreased ratio of NAD+/NADH was observed, motivating the use of hyperpolarized magnetic resonance spectroscopy (HP-MRS) to detect treatment response. Spectroscopic experiments were performed on tumor spheroids, 3D structures that self-organize in the presence of an extracellular matrix. Treated spheroids showed decreased lactate production with on-target inhibition confirmed using IHC, demonstrating that HP-MRS can be used to probe treatment response in prostate cancer spheroids and can provide a biomarker for treatment response. Mol Cancer Res; 16(3); 453–60. ©2018 AACR.
Data from Genome Sequencing and RNA-Motif Analysis Reveal Novel Damaging Noncoding Mutations in Human Tumors
Authors: Singh Babita , Trincado Juan L. , Tatlow PJ , Piccolo Stephen R. , Eyras Eduardo
Published: April 2023

Abstract
A major challenge in cancer research is to determine the biological and clinical significance of somatic mutations in noncoding regions. This has been studied in terms of recurrence, functional impact, and association to individual regulatory sites, but the combinatorial contribution of mutations to common RNA regulatory motifs has not been explored. Therefore, we developed a new method, MIRA (mutation identification for RNA alterations), to perform an unbiased and comprehensive study of significantly mutated regions (SMR) affecting binding sites for RNA-binding proteins (RBP) in cancer. Extracting signals related to RNA-related selection processes and using RNA sequencing (RNA-seq) data from the same specimens, we identified alterations in RNA expression and splicing linked to mutations on RBP binding sites. We found SRSF10 and MBNL1 motifs in introns, HNRPLL motifs at 5′ UTRs, as well as 5′ and 3′ splice-site motifs, among others, with specific mutational patterns that disrupt the motif and impact RNA processing. MIRA facilitates the integrative analysis of multiple genome sites that operate collectively through common RBPs and aids in the interpretation of noncoding variants in cancer. MIRA is available at https://github.com/comprna/mira.

Implications: The study of recurrent cancer mutations on potential RBP binding sites reveals new alterations in introns, untranslated regions, and long noncoding RNAs that impact RNA processing and provide a new layer of insight that can aid in the interpretation of noncoding variants in cancer genomes. Mol Cancer Res; 16(7); 1112–24. ©2018 AACR.
Data from SREBF1 Activity Is Regulated by an AR/mTOR Nuclear Axis in Prostate Cancer
Authors: Audet-Walsh Étienne , Vernier Mathieu , Yee Tracey , Laflamme Chloé , Li Susan , Chen Yonghong , Giguère Vincent
Published: April 2023

Abstract
Reprogramming of cellular metabolism is an important feature of prostate cancer, including altered lipid metabolism. Recently, it was observed that the nuclear fraction of mTOR is essential for the androgen-mediated metabolic reprogramming of prostate cancer cells. Herein, it is demonstrated that the androgen receptor (AR) and mTOR bind to regulatory regions of sterol regulatory element-binding transcription factor 1 (SREBF1) to control its expression, whereas dual activation of these signaling pathways also promotes SREBF1 cleavage and its translocation to the nucleus. Consequently, SREBF1 recruitment to regulatory regions of its target genes is induced upon treatment with the synthetic androgen R1881, an effect abrogated upon inhibition of the mTOR signaling pathway. In turn, pharmacologic and genetic inhibition of SREBF1 activity impairs the androgen-mediated induction of the key lipogenic genes fatty acid synthase (FASN) and stearoyl-CoA desaturase (SCD1). Consistent with these observations, the expression of the SREBF1, FASN, and SCD1 genes is significantly correlated in human prostate cancer tumor clinical specimens. Functionally, blockade of SREBF1 activity reduces the androgen-driven lipid accumulation. Interestingly, decreased triglyceride accumulation observed upon SREBF1 inhibition is paralleled by an increase in mitochondrial respiration, indicating a potential rewiring of citrate metabolism in prostate cancer cells. Altogether, these data define an AR/mTOR nuclear axis, in the context of prostate cancer, as a novel pathway regulating SREBF1 activity and citrate metabolism.

Implications: The finding that an AR/mTOR complex promotes SREBF1 expression and activity enhances our understanding of the metabolic adaptation necessary for prostate cancer cell growth and suggests novel therapeutic approaches to target metabolic vulnerabilities in tumors. Mol Cancer Res; 16(9); 1396–405. ©2018 AACR.
Data from Antisecretory Factor–Mediated Inhibition of Cell Volume Dynamics Produces Antitumor Activity in Glioblastoma
Authors: Ilkhanizadeh Shirin , Sabelström Hanna , Miroshnikova Yekaterina A. , Frantz Aaron , Zhu Wen , Idilli Aurora , Lakins Jon N. , Schmidt Christin , Quigley David A. , Fenster Trenten , Yuan Edith , Trzeciak Jacqueline R. , Saxena Supna , Lindberg Olle R. , Mouw Janna K. , Burdick Jason A. , Magnitsky Sergey , Berger Mitchel S. , Phillips Joanna J. , Arosio Daniele , Sun Dandan , Weaver Valerie M. , Weiss William A. , Persson Anders I.
Published: April 2023

Abstract
Interstitial fluid pressure (IFP) presents a barrier to drug uptake in solid tumors, including the aggressive primary brain tumor glioblastoma (GBM). It remains unclear how fluid dynamics impacts tumor progression and can be targeted therapeutically. To address this issue, a novel telemetry-based approach was developed to measure changes in IFP during progression of GBM xenografts. Antisecretory factor (AF) is an endogenous protein that displays antisecretory effects in animals and patients. Here, endogenous induction of AF protein or exogenous administration of AF peptide reduced IFP and increased drug uptake in GBM xenografts. AF inhibited cell volume regulation of GBM cells, an effect that was phenocopied in vitro by the sodium-potassium-chloride cotransporter 1 (SLC12A2/NKCC1) inhibitor bumetanide. As a result, AF induced apoptosis and increased survival in GBM models. In vitro, the ability of AF to reduce GBM cell proliferation was phenocopied by bumetanide and NKCC1 knockdown. Next, AF's ability to sensitize GBM cells to the alkylating agent temozolomide, standard of care in GBM patients, was evaluated. Importantly, combination of AF induction and temozolomide treatment blocked regrowth in GBM xenografts. Thus, AF-mediated inhibition of cell volume regulation represents a novel strategy to increase drug uptake and improve outcome in GBM. Mol Cancer Res; 16(5); 777–90. ©2018 AACR.
Data from Olaparib-induced Adaptive Response Is Disrupted by FOXM1 Targeting that Enhances Sensitivity to PARP Inhibition
Authors: Fang Pingping , Madden Jill A. , Neums Lisa , Moulder Ryan K. , Forrest M. Laird , Chien Jeremy
Published: April 2023

Abstract
FOXM1 transcription factor network is activated in over 84% of cases in high-grade serous ovarian cancer (HGSOC), and FOXM1 upregulates the expression of genes involved in the homologous recombination (HR) DNA damage and repair (DDR) pathway. However, the role of FOXM1 in PARP inhibitor response has not yet been studied. This study demonstrates that PARP inhibitor (PARPi), olaparib, induces the expression and nuclear localization of FOXM1. On the basis of ChIP-qPCR, olaparib enhances the binding of FOXM1 to genes involved in HR repair. FOXM1 knockdown by RNAi or inhibition by thiostrepton decreases FOXM1 expression, decreases the expression of HR repair genes, such as BRCA1 and RAD51, and enhances sensitivity to olaparib. Comet and PARP trapping assays revealed increases in DNA damage and PARP trapping in FOXM1-inhibited cells treated with olaparib. Finally, thiostrepton decreases the expression of BRCA1 in rucaparib-resistant cells and enhances sensitivity to rucaparib. Collectively, these results identify that FOXM1 plays an important role in the adaptive response induced by olaparib and FOXM1 inhibition by thiostrepton induces “BRCAness” and enhances sensitivity to PARP inhibitors.

Implications: FOXM1 inhibition represents an effective strategy to overcome resistance to PARPi, and targeting FOXM1-mediated adaptive pathways may produce better therapeutic effects for PARP inhibitors. Mol Cancer Res; 16(6); 961–73. ©2018 AACR.
Data from ERβ Sensitizes NSCLC to Chemotherapy by Regulating DNA Damage Response
Authors: Nikolos Fotis , Thomas Christoforos , Bado Igor , Gustafsson Jan-Åke
Published: April 2023

Abstract
The expression of wild-type estrogen receptor β (ESR2/ERβ1) correlates with clinical outcome in patients with non–small cell lung cancer (NSCLC). However, the molecular mechanism that accounts for this association is currently poorly understood. ERβ1 was previously linked to chemotherapy response in patients with breast cancer and in breast cancer cells. The effect of the receptor in NSCLC cells after chemotherapy treatment, a common remedy for advanced NSCLC, has not been studied. Here, upregulation of ERβ1 increases the sensitivity of NSCLC cells to treatment with doxorubicin and etoposide. This effect was primarily observed in p53-defecient NSCLC cells. In these cells, ERβ1 either enhanced G2–M cell-cycle arrest by activating the checkpoint kinase 1 (Chk1) and altering downstream signaling or induced apoptosis. The expression of p63 target genes that control G2–M checkpoint activation was altered by ERβ1 suggesting an ERβ1–p63 transcriptional cooperation in lung cancer cells that affects DNA damage response (DDR). These results suggest involvement of ERβ1 in the mechanism that regulates DNA damage response in NSCLC cells and support the potential predictive and therapeutic value of the receptor in clinical management of the disease.

Implications: This study demonstrating the impact of ERβ1 on chemosensitivity of NSCLC cells suggests the predictive value of the receptor for successful response of tumors to chemotherapy and the potential benefit of chemotherapy-treated patients from the use of ER ligands. Mol Cancer Res; 16(2); 233–42. ©2017 AACR.