bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Genetic and Epigenetic Characterization of Growth Hormone–Secreting Pituitary Tumors
Authors: Välimäki Niko , Schalin-Jäntti Camilla , Karppinen Atte , Paetau Anders , Kivipelto Leena , Aaltonen Lauri A. , Karhu Auli
Published: March 2024

Abstract
Somatic driver mechanisms of pituitary adenoma pathogenesis have remained incompletely characterized; apart from mutations in the stimulatory Gα protein (Gαs encoded by GNAS) causing activated cAMP synthesis, pathogenic variants are rarely found in growth hormone–secreting pituitary tumors (somatotropinomas). The purpose of the current work was to clarify how genetic and epigenetic alterations contribute to the development of somatotropinomas by conducting an integrated copy number alteration, whole-genome and bisulfite sequencing, and transcriptome analysis of 21 tumors. Somatic mutation burden was low, but somatotropinomas formed two subtypes associated with distinct aneuploidy rates and unique transcription profiles. Tumors with recurrent chromosome aneuploidy (CA) were GNAS mutation negative (Gsp−). The chromosome stable (CS) –group contained Gsp+ somatotropinomas and two totally aneuploidy-free Gsp− tumors. Genes related to the mitotic G1–S-checkpoint transition were differentially expressed in CA- and CS-tumors, indicating difference in mitotic progression. Also, pituitary tumor transforming gene 1 (PTTG1), a regulator of sister chromatid segregation, showed abundant expression in CA-tumors. Moreover, somatotropinomas displayed distinct Gsp genotype–specific methylation profiles and expression quantitative methylation (eQTM) analysis revealed that inhibitory Gα (Gαi) signaling is activated in Gsp+ tumors. These findings suggest that aneuploidy through modulated driver pathways may be a causative mechanism for tumorigenesis in Gsp− somatotropinomas, whereas Gsp+ tumors with constitutively activated cAMP synthesis seem to be characterized by DNA methylation activated Gαi signaling.
Implications:
These findings provide valuable new information about subtype-specific pituitary tumorigenesis and may help to elucidate the mechanisms of aneuploidy also in other tumor types.
Data from Reprogramming of Isocitrate Dehydrogenases Expression and Activity by the Androgen Receptor in Prostate Cancer
Authors: Gonthier Kevin , Poluri Raghavendra Tejo Karthik , Weidmann Cindy , Tadros Maude , Audet-Walsh Étienne
Published: March 2024

Abstract
Mutations of the isocitrate dehydrogenase genes IDH1 and IDH2, key enzymes involved in citrate metabolism, are important oncogenic events in several cancer types, including in 1%–3% of all prostate cancer cases. However, if IDH1 and other IDH isoforms are associated with prostate cancer progression, as well as the regulatory factors controlling their expression and activity, remain mostly unknown. Using publicly available datasets, we showed that prostate cancer harbors the highest IDH1 expression across the human cancer spectrum and that IDH1 expression is altered during prostate cancer progression. We showed that the androgen receptor (AR), a key oncogene in prostate cancer, controls multiple IDH isoforms in both in vitro and in vivo models, predominantly positively regulating IDH1. Chromatin immunoprecipitation experiments confirmed the recruitment of AR at several regulatory regions of IDH1 and enzymatic assays demonstrated that AR significantly induces IDH activity. Genetic blockade of IDH1 significantly impaired prostate cancer cell proliferation, consistent with IDH1 having a key function in these cancer cells. Importantly, knockdown of IDH1 blocked the AR-mediated induction in IDH activity, indicating that AR promotes a mitochondrial to cytoplasmic reprogramming of IDH activity. Overall, our study demonstrates that IDH1 expression is associated with prostate cancer progression, that AR signaling integrates one of the first transcriptional mechanisms shown to regulate IDH1, and that AR reprograms prostate cancer cell metabolism by selectively inducing extra-mitochondrial IDH activity.
Implications:
The discovery that AR reprograms IDH activity highlights a novel metabolic reprogramming necessary for prostate cancer growth and suggests targeting IDH activity as a new therapeutic approach for prostate cancer treatment.
Data from Identification of TP53RK-Binding Protein (TPRKB) Dependency in TP53-Deficient Cancers
Authors: Goswami Moloy T. , VanDenBerg Kelly R. , Han Sumin , Wang Lei Lucy , Singh Bhavneet , Weiss Travis , Barlow Myles , Kamberov Steven , Wilder-Romans Kari , Rhodes Daniel R. , Feng Felix Y. , Tomlins Scott A.
Published: March 2024

Abstract
Tumor protein 53 (TP53; p53) is the most frequently altered gene in human cancer. Identification of vulnerabilities imposed by TP53 alterations may enable effective therapeutic approaches. Through analyzing short hairpin RNA (shRNA) screening data, we identified TP53RK-Binding Protein (TPRKB), a poorly characterized member of the tRNA-modifying EKC/KEOPS complex, as the most significant vulnerability in TP53-mutated cancer cell lines. In vitro and in vivo, across multiple benign-immortalized and cancer cell lines, we confirmed that TPRKB knockdown in TP53-deficient cells significantly inhibited proliferation, with minimal effect in TP53 wild-type cells. TP53 reintroduction into TP53-null cells resulted in loss of TPRKB sensitivity, confirming the importance of TP53 status in this context. In addition, cell lines with mutant TP53 or amplified MDM2 (E3-ubiquitin ligase for TP53) also showed high sensitivity to TPRKB knockdown, consistent with TPRKB dependence in a wide array of TP53-altered cancers. Depletion of other EKC/KEOPS complex members exhibited TP53-independent effects, supporting complex-independent functions of TPRKB. Finally, we found that TP53 indirectly mediates TPRKB degradation, which was rescued by coexpression of PRPK, an interacting member of the EKC/KEOPS complex, or proteasome inhibition. Together, these results identify a unique and specific requirement of TPRKB in a variety of TP53-deficient cancers.
Implications:
Cancer cells with genomic alterations in TP53 are dependent on TPRKB.
Data from Epigenetic Suppression of SERPINB1 Promotes Inflammation-Mediated Prostate Cancer Progression
Authors: Lerman Irina , Ma Xiaoting , Seger Christina , Maolake Aerken , Garcia-Hernandez Maria de la Luz , Rangel-Moreno Javier , Ackerman Jessica , Nastiuk Kent L. , Susiarjo Martha , Hammes Stephen R.
Published: March 2024

Abstract
Granulocytic myeloid infiltration and resultant enhanced neutrophil elastase (NE) activity is associated with poor outcomes in numerous malignancies. We recently showed that NE expression and activity from infiltrating myeloid cells was high in human prostate cancer xenografts and mouse Pten-null prostate tumors. We further demonstrated that NE directly stimulated human prostate cancer cells to proliferate, migrate, and invade, and inhibition of NE in vivo attenuated xenograft growth. Interestingly, reduced expression of SERPINB1, an endogenous NE inhibitor, also correlates with diminished survival in some cancers. Therefore, we sought to characterize the role of SERPINB1 in prostate cancer. We find that SERPINB1 expression is reduced in human metastatic and locally advanced disease and predicts poor outcome. SERPINB1 is also reduced in Pten-null mouse prostate tumors compared with wild-type prostates, and treatment with sivelestat (SERPINB1 pharmacomimetic) attenuates tumor growth. Knockdown of highly expressed SERPINB1 in nonmalignant prostatic epithelial cells (RWPE-1) increases proliferation, decreases apoptosis, and stimulates expression of epithelial-to-mesenchymal transition markers. In contrast, stable SERPINB1 expression in normally low-expressing prostate cancer cells (C4-2) reduces xenograft growth in vivo. Finally, EZH2-mediated histone (H3K27me3) methylation and DNA methyltransferase–mediated DNA methylation suppress SERPINB1 expression in prostate cancer cells. Analysis of The Cancer Genome Atlas and pyrosequencing demonstrate hypermethylation of the SERPINB1 promoter in prostate cancer compared with normal tissue, and the extent of promoter methylation negatively correlates with SERPINB1 mRNA expression.
Implications:
Our findings suggest that the balance between SERPINB1 and NE is physiologically important within the prostate and may serve as a biomarker and therapeutic target in prostate cancer.
Data from A Transcriptional Program for Detecting TGFβ-Induced EMT in Cancer
Authors: Foroutan Momeneh , Cursons Joseph , Hediyeh-Zadeh Soroor , Thompson Erik W. , Davis Melissa J.
Published: March 2024

Abstract
Most cancer deaths are due to metastasis, and epithelial-to-mesenchymal transition (EMT) plays a central role in driving cancer cell metastasis. EMT is induced by different stimuli, leading to different signaling patterns and therapeutic responses. TGFβ is one of the best-studied drivers of EMT, and many drugs are available to target this signaling pathway. A comprehensive bioinformatics approach was employed to derive a signature for TGFβ-induced EMT which can be used to score TGFβ-driven EMT in cells and clinical specimens. Considering this signature in pan-cancer cell and tumor datasets, a number of cell lines (including basal B breast cancer and cancers of the central nervous system) show evidence for TGFβ-driven EMT and carry a low mutational burden across the TGFβ signaling pathway. Furthermore, significant variation is observed in the response of high scoring cell lines to some common cancer drugs. Finally, this signature was applied to pan-cancer data from The Cancer Genome Atlas to identify tumor types with evidence of TGFβ-induced EMT. Tumor types with high scores showed significantly lower survival rates than those with low scores and also carry a lower mutational burden in the TGFβ pathway. The current transcriptomic signature demonstrates reproducible results across independent cell line and cancer datasets and identifies samples with strong mesenchymal phenotypes likely to be driven by TGFβ.

Implications: The TGFβ-induced EMT signature may be useful to identify patients with mesenchymal-like tumors who could benefit from targeted therapeutics to inhibit promesenchymal TGFβ signaling and disrupt the metastatic cascade. Mol Cancer Res; 15(5); 619–31. ©2017 AACR.
Data from Next-Generation Sequencing Analysis and Algorithms for PDX and CDX Models
Authors: Khandelwal Garima , Girotti María Romina , Smowton Christopher , Taylor Sam , Wirth Christopher , Dynowski Marek , Frese Kristopher K. , Brady Ged , Dive Caroline , Marais Richard , Miller Crispin
Published: March 2024

Abstract
Patient-derived xenograft (PDX) and circulating tumor cell–derived explant (CDX) models are powerful methods for the study of human disease. In cancer research, these methods have been applied to multiple questions, including the study of metastatic progression, genetic evolution, and therapeutic drug responses. As PDX and CDX models can recapitulate the highly heterogeneous characteristics of a patient tumor, as well as their response to chemotherapy, there is considerable interest in combining them with next-generation sequencing to monitor the genomic, transcriptional, and epigenetic changes that accompany oncogenesis. When used for this purpose, their reliability is highly dependent on being able to accurately distinguish between sequencing reads that originate from the host, and those that arise from the xenograft itself. Here, we demonstrate that failure to correctly identify contaminating host reads when analyzing DNA- and RNA-sequencing (DNA-Seq and RNA-Seq) data from PDX and CDX models is a major confounding factor that can lead to incorrect mutation calls and a failure to identify canonical mutation signatures associated with tumorigenicity. In addition, a highly sensitive algorithm and open source software tool for identifying and removing contaminating host sequences is described. Importantly, when applied to PDX and CDX models of melanoma, these data demonstrate its utility as a sensitive and selective tool for the correction of PDX- and CDX-derived whole-exome and RNA-Seq data.

Implications: This study describes a sensitive method to identify contaminating host reads in xenograft and explant DNA- and RNA-Seq data and is applicable to other forms of deep sequencing. Mol Cancer Res; 15(8); 1012–6. ©2017 AACR.
Data from A Role for Tryptophan-2,3-dioxygenase in CD8 T-cell Suppression and Evidence of Tryptophan Catabolism in Breast Cancer Patient Plasma
Authors: Greene Lisa I. , Bruno Tullia C. , Christenson Jessica L. , D'Alessandro Angelo , Culp-Hill Rachel , Torkko Kathleen , Borges Virginia F. , Slansky Jill E. , Richer Jennifer K.
Published: March 2024

Abstract
Tryptophan catabolism is an attractive target for reducing tumor progression and improving antitumor immunity in multiple cancers. Tumor infiltration by CD8 T cells correlates with improved prognosis in triple-negative breast cancer (TNBC) and a significant effort is underway to improve CD8 T-cell antitumor activity. In this study, primary human immune cells were isolated from the peripheral blood of patients and used to demonstrate that the tryptophan catabolite kynurenine induces CD8 T-cell death. Furthermore, it is demonstrated that anchorage-independent TNBC utilizes the tryptophan-catabolizing enzyme tryptophan 2,3-dioxygenase (TDO) to inhibit CD8 T-cell viability. Publicly available data revealed that high TDO2, the gene encoding TDO, correlates with poor breast cancer clinical outcomes, including overall survival and distant metastasis-free survival, while expression of the gene encoding the more commonly studied tryptophan-catabolizing enzyme, IDO1 did not. Metabolomic analysis, using quantitative mass spectrometry, of tryptophan and its catabolites, including kynurenine, in the plasma from presurgical breast cancer patients (n = 77) and 40 cancer-free donors (n = 40) indicated a strong correlation between substrate and catabolite in both groups. Interestingly, both tryptophan and kynurenine were lower in the plasma from patients with breast cancer compared with controls, particularly in women with estrogen receptor (ER)-negative and stage III and IV breast cancer.
Implications:
This study underscores the importance of tryptophan catabolism, particularly in aggressive disease, and suggests that future pharmacologic efforts should focus on developing drugs that target both TDO and IDO1.
Data from Genetic and Epigenetic Determinants of Aggressiveness in Cribriform Carcinoma of the Prostate
Authors: Elfandy Habiba , Armenia Joshua , Pederzoli Filippo , Pullman Eli , Pertega-Gomes Nelma , Schultz Nikolaus , Viswanathan Kartik , Vosoughi Aram , Blattner Mirjam , Stopsack Konrad H. , Zadra Giorgia , Penney Kathryn L. , Mosquera Juan Miguel , Tyekucheva Svitlana , Mucci Lorelei A. , Barbieri Christopher , Loda Massimo
Published: March 2024

Abstract
Among prostate cancers containing Gleason pattern 4, cribriform morphology is associated with unfavorable clinicopathologic factors, but its genetic features and association with long-term outcomes are incompletely understood. In this study, genetic, transcriptional, and epigenetic features of invasive cribriform carcinoma (ICC) tumors were compared with non-cribriform Gleason 4 (NC4) in The Cancer Genome Atlas (TCGA) cohort. ICC (n = 164) had distinctive molecular features when compared with NC4 (n = 102). These include: (i) increased somatic copy number variations (SCNV), specifically deletions at 6q, 8p and 10q, which encompassed PTEN and MAP3K7 losses and gains at 3q; (ii) increased SPOPmut and ATMmut; (iii) enrichment for mTORC1 and MYC pathways by gene expression; and (iv) increased methylation of selected genes. In addition, when compared with the metastatic prostate cancer, ICC clustered more closely to metastatic prostate cancer than NC4. Validation in clinical cohorts and genomically annotated murine models confirmed the association with SPOPmut (n = 38) and PTENloss (n = 818). The association of ICC with lethal disease was evaluated in the Health Professionals Follow-up Study (HPFS) and Physicians' Health Study (PHS) prospective prostate cancer cohorts (median follow-up, 13.4 years; n = 818). Patients with ICC were more likely to develop lethal cancer [HR, 1.62; 95% confidence interval (CI), 1.05–2.49], independent from Gleason score (GS).
Implications:
ICC has a distinct molecular phenotype that resembles metastatic prostate cancer and is associated with progression to lethal disease.
Data from Distinct Afatinib Resistance Mechanisms Identified in Lung Adenocarcinoma Harboring an EGFR Mutation
Authors: Yamaoka Toshimitsu , Ohmori Tohru , Ohba Motoi , Arata Satoru , Murata Yasunori , Kusumoto Sojiro , Ando Koichi , Ishida Hiroo , Ohnishi Tsukasa , Sasaki Yasutsuna
Published: March 2024

Abstract
EGFR tyrosine kinase inhibitors (TKI) are associated with significant responses in non–small cell lung cancer (NSCLC) patients harboring EGFR-activating mutations. However, acquired resistance to reversible EGFR-TKIs remains a major obstacle. In particular, although the second-generation irreversible EGFR-TKI afatinib is currently used for treating NSCLC patients, the mechanisms underlying acquired afatinib resistance remain poorly understood. Here, heterogeneous mechanisms of acquired resistance were identified following long-term exposure to increasing doses of afatinib in EGFR-mutant lung adenocarcinoma PC-9 cells. Notably, three resistant cell lines, PC-9AFR1, PC-9AFR2, and PC-9AFR3 (AFR1, AFR2, and AFR3, respectively) employed distinct mechanisms for avoiding EGFR inhibition, with increased EGFR expression being detected in all resistant cell lines. Moreover, an activating EGFR mutation was partially lost in AFR1 and AFR2 cells. AFR1 cells exhibited afatinib resistance as a result of wild-type KRAS amplification and overexpression; however, these cells showed a progressive decrease and eventual loss of the acquired KRAS dependence, as well as resensitization to afatinib, following a drug holiday. Meanwhile, AFR2 cells exhibited increased expression of insulin-like growth factor-binding protein 3 (IGFBP3), which promoted insulin-like growth factor 1 receptor (IGF1R) activity and subsequent AKT phosphorylation, thereby indicating a potential bypass signaling pathway associated with IGFR1. Finally, AFR3 cells harbored the secondary EGFR mutation T790M. Our findings constitute the first report showing acquired wild-type KRAS overexpression and attenuation of afatinib resistance following a drug holiday.

Implications: The heterogeneous mechanisms of afatinib resistance should facilitate the development of more effective therapeutic strategies for NSCLC patients. Mol Cancer Res; 15(7); 915–28. ©2017 AACR.
Data from Senescent Carcinoma-Associated Fibroblasts Upregulate IL8 to Enhance Prometastatic Phenotypes
Authors: Wang Tao , Notta Faiyaz , Navab Roya , Joseph Joella , Ibrahimov Emin , Xu Jing , Zhu Chang-Qi , Borgida Ayelet , Gallinger Steven , Tsao Ming-Sound
Published: March 2024

Abstract
Carcinoma-associated fibroblasts (CAF) represent a significant component of pancreatic cancer stroma and are biologically implicated in tumor progression. However, evidence of both cancer-promoting and -restraining properties amongst CAFs suggests the possibility of multiple phenotypic subtypes. Here, it is demonstrated that senescent CAFs promote pancreatic cancer invasion and metastasis compared with nonsenescent control CAFs using in vitro Transwell invasion models and in vivo xenograft mouse models. Screening by gene expression microarray and cytokine ELISA assays revealed IL8 to be upregulated in senescent CAFs. Experimental modulation through IL8 overexpression or receptor inhibition implicates the IL8 pathway as a mediator of the proinvasive effects of senescent CAFs. In a cohort of human pancreatic cancer cases, more abundant stromal senescence as indicated by p16 immunohistochemistry correlated with decreased survival in patients with early-stage disease. These data support senescent fibroblasts as a pathologically and clinically relevant feature of pancreatic cancer. The inhibition of senescent stroma–cancer signaling pathways has the potential to restrain pancreatic cancer progression.

Implications: Findings show that senescent cancer-associated fibroblasts secret excess IL8 to promote pancreatic cancer invasion and metastasis; thus, senescent CAFs represent a phenotypic subtype, challenging conventional assumptions that CAFs are a homogeneous population. Mol Cancer Res; 15(1); 3–14. ©2016 AACR.
Data from Genome-Wide Analysis in a Murine Dnmt1 Knockdown Model Identifies Epigenetically Silenced Genes in Primary Human Pituitary Tumors
Authors: Dudley Kevin J. , Revill Kate , Whitby Philip , Clayton Richard N. , Farrell William E.
Published: March 2024

Abstract
DNA methylation at promoter CpG islands (CGI) is an epigenetic modification associated with inappropriate gene silencing in multiple tumor types. In the absence of a human pituitary tumor cell line, small interfering RNA–mediated knockdown of the maintenance methyltransferase DNA methyltransferase (cytosine 5)-1 (Dnmt1) was used in the murine pituitary adenoma cell line AtT-20. Sustained knockdown induced reexpression of the fully methylated and normally imprinted gene neuronatin (Nnat) in a time-dependent manner. Combined bisulfite restriction analysis (COBRA) revealed that reexpression of Nnat was associated with partial CGI demethylation, which was also observed at the H19 differentially methylated region. Subsequent genome-wide microarray analysis identified 91 genes that were significantly differentially expressed in Dnmt1 knockdown cells (10% false discovery rate). The analysis showed that genes associated with the induction of apoptosis, signal transduction, and developmental processes were significantly overrepresented in this list (P < 0.05). Following validation by reverse transcription-PCR and detection of inappropriate CGI methylation by COBRA, four genes (ICAM1, NNAT, RUNX1, and S100A10) were analyzed in primary human pituitary tumors, each displaying significantly reduced mRNA levels relative to normal pituitary (P < 0.05). For two of these genes, NNAT and S100A10, decreased expression was associated with increased promoter CGI methylation. Induced expression of Nnat in stable transfected AtT-20 cells inhibited cell proliferation. To our knowledge, this is the first report of array-based “epigenetic unmasking” in combination with Dnmt1 knockdown and reveals the potential of this strategy toward identifying genes silenced by epigenetic mechanisms across species boundaries. (Mol Cancer Res 2008;6(10):1567–74)
Data from CDK4/6 Therapeutic Intervention and Viable Alternative to Taxanes in CRPC
Authors: Stice James P. , Wardell Suzanne E. , Norris John D. , Yllanes Alexander P. , Alley Holly M. , Haney Victoria O. , White Hannah S. , Safi Rachid , Winter Peter S. , Cocce Kimberly J. , Kishton Rigel J. , Lawrence Scott A. , Strum Jay C. , McDonnell Donald P.
Published: March 2024

Abstract
Resistance to second-generation androgen receptor (AR) antagonists and CYP17 inhibitors in patients with castration-resistant prostate cancer (CRPC) develops rapidly through reactivation of the androgen signaling axis and has been attributed to AR overexpression, production of constitutively active AR splice variants, or the selection for AR mutants with altered ligand-binding specificity. It has been established that androgens induce cell-cycle progression, in part, through upregulation of cyclin D1 (CCND1) expression and subsequent activation of cyclin-dependent kinases 4 and 6 (CDK4/6). Thus, the efficacy of the newly described CDK4/6 inhibitors (G1T28 and G1T38), docetaxel and enzalutamide, was evaluated as single agents in clinically relevant in vitro and in vivo models of hormone-sensitive and treatment-resistant prostate cancer. CDK4/6 inhibition (CDK4/6i) was as effective as docetaxel in animal models of treatment-resistant CRPC but exhibited significantly less toxicity. The in vivo effects were durable and importantly were observed in prostate cancer cells expressing wild-type AR, AR mutants, and those that have lost AR expression. CDK4/6i was also effective in prostate tumor models expressing the AR-V7 variant or the AR F876L mutation, both of which are associated with treatment resistance. Furthermore, CDK4/6i was effective in prostate cancer models where AR expression was lost. It is concluded that CDK4/6 inhibitors are a viable alternative to taxanes as therapeutic interventions in endocrine therapy–refractory CRPC.

Implications: The preclinical efficacy of CDK4/6 monotherapy observed here suggests the need for near-term clinical studies of these agents in advanced prostate cancer. Mol Cancer Res; 15(6); 660–9. ©2017 AACR.
Data from FES Kinase Promotes Mast Cell Recruitment to Mammary Tumors via the Stem Cell Factor/KIT Receptor Signaling Axis
Authors: Kwok Ester , Everingham Stephanie , Zhang Shengnan , Greer Peter A. , Allingham John S. , Craig Andrew W.B.
Published: March 2024

Abstract
KIT receptor is required for mast cell development, survival, and migration toward its ligand stem cell factor (SCF). Many solid tumors express SCF and this leads to mast cell recruitment to tumors and release of mediators linked to tumor angiogenesis, growth, and metastasis. Here, we investigate whether FES protein-tyrosine kinase, a downstream effector of KIT signaling in mast cells, is required for migration of mast cells toward SCF-expressing mammary tumors. Using a novel agarose drop assay for chemotaxis of bone marrow–derived mast cells (BMMC) toward SCF, we found that defects in chemotaxis of fes-null BMMCs correlated with disorganized microtubule networks in polarized cells. FES displayed partial colocalization with microtubules in polarized BMMCs and has at least two direct microtubule binding sites within its N-terminal F-BAR and SH2 domains. An oligomerization-disrupting mutation within the Fer/CIP4 homology-Bin/Amphiphysin/Rvs (F-BAR) domain had no effect on microtubule binding, whereas microtubule binding to the SH2 domain was dependent on the phosphotyrosine-binding pocket. FES involvement in mast cell recruitment to tumors was tested using the AC2M2 mouse mammary carcinoma model. These tumor cells expressed SCF and promoted BMMC recruitment in a KIT- and FES-dependent manner. Engraftment of AC2M2 orthotopic and subcutaneous tumors in control or fes-null mice, revealed a key role for FES in recruitment of mast cells to the tumor periphery. This may contribute to the reduced tumor growth and metastases observed in fes-null mice compared with control mice. Taken together, FES is a potential therapeutic target to limit the progression of tumors with stromal mast cell involvement. Mol Cancer Res; 10(7); 881–91. ©2012 AACR.
Data from Complex Rab4-Mediated Regulation of Endosomal Size and EGFR Activation
Authors: Tubbesing Kate , Ward Jamie , Abini-Agbomson Raymond , Malhotra Aditi , Rudkouskaya Alena , Warren Janine , Lamar John , Martino Nina , Adam Alejandro P. , Barroso Margarida
Published: March 2024

Abstract
Early sorting endosomes are responsible for the trafficking and function of transferrin receptor (TfR) and EGFR. These receptors play important roles in iron uptake and signaling and are critical for breast cancer development. However, the role of morphology, receptor composition, and signaling of early endosomes in breast cancer remains poorly understood. A novel population of enlarged early endosomes was identified in breast cancer cells and tumor xenografts but not in noncancerous MCF10A cells. Quantitative analysis of endosomal morphology, cargo sorting, EGFR activation, and Rab GTPase regulation was performed using super-resolution and confocal microscopy followed by 3D rendering. MDA-MB-231 breast cancer cells have fewer, but larger EEA1-positive early endosomes compared with MCF10A cells. Live-cell imaging indicated dysregulated cargo sorting, because EGF and Tf traffic together via enlarged endosomes in MDA-MB-231, but not in MCF10A. Large EEA1-positive MDA-MB-231 endosomes exhibited prolonged and increased EGF-induced activation of EGFR upon phosphorylation at tyrosine-1068 (EGFR-p1068). Rab4A overexpression in MCF10A cells produced EEA1-positive enlarged endosomes that displayed prolonged and amplified EGF-induced EGFR-p1068 activation. Knockdown of Rab4A lead to increased endosomal size in MCF10A, but not in MDA-MB-231 cells. Nevertheless, Rab4A knockdown resulted in enhanced EGF-induced activation of EGFR-p1068 in MDA-MB-231 as well as downstream signaling in MCF10A cells. Altogether, this extensive characterization of early endosomes in breast cancer cells has identified a Rab4-modulated enlarged early endosomal compartment as the site of prolonged and increased EGFR activation.
Implications:
Enlarged early endosomes play a Rab4-modulated role in regulation of EGFR activation in breast cancer cells.
Data from TNF-α Induces Epithelial–Mesenchymal Transition of Renal Cell Carcinoma Cells via a GSK3β-Dependent Mechanism
Authors: Ho Ming-Yi , Tang Shye-Jye , Chuang Mei-Jen , Cha Tai-Lung , Li Jing-Yao , Sun Guang-Huan , Sun Kuang-Hui
Published: March 2024

Abstract
TNF-α is a cytokine with antitumorigenic property. In contrast, low dose, chronic TNF-α production by tumor cells or stromal cells may promote tumor growth and metastasis. Serum levels of TNF-α are significantly elevated in renal cell carcinoma (RCC) patients. Here, we showed that TNF-α induced epithelial–mesenchymal transition (EMT) and promoted tumorigenicity of RCC by repressing E-cadherin, upregulating vimentin, activating MMP9, and invasion activities. In addition, TNF-α treatment inhibited glycogen synthase kinase 3β (GSK-3β) activity through serine-9 phosphorylation mediated by the phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) pathway in RCC cells. Inhibition of PI3K/AKT by LY294002 reactivated GSK-3β and suppressed the TNF-α–induced EMT of RCC cells. Inactivation of GSK-3β by LiCl significantly increased MMP9 activity and EMT of RCC cells. Activation of GSK-3β by transduction of constitutively active GSK-3β into RCC cells suppressed TNF-α–mediated anchorage-independent growth in soft agar and tumorigenicity in nude mice. Overexpression of a kinase-deficient GSK-3β, in contrast, potentiated EMT, anchorage-independent growth and drastically enhanced tumorigenicity in vivo. Most importantly, a 15-fold inactivation of GSK-3β activity, 3-fold decrease of E-cadherin, and 2-fold increase of vimentin were observed in human RCC tumor tissues. These results indicated that inactivation of GSK-3β plays a pivotal role in the TNF-α–mediated tumorigenesis of RCC. Mol Cancer Res; 10(8); 1109–19. ©2012 AACR.
Data from Expression of Wnt3 Activates Wnt/β-Catenin Pathway and Promotes EMT-like Phenotype in Trastuzumab-Resistant HER2-Overexpressing Breast Cancer Cells
Authors: Wu Yanyuan , Ginther Charles , Kim Juri , Mosher Nicole , Chung Seyung , Slamon Dennis , Vadgama Jaydutt V.
Published: March 2024

Abstract
To understand the mechanisms leading to trastuzumab resistance in HER2-overexpressing breast tumors, we created trastuzumab-insensitive cell lines (SKBR3/100-8 and BT474/100-2). The cell lines maintain HER2 receptor overexpression and show increase in EGF receptor (EGFR). Upon trastuzumab treatment, SKBR3/100-8 and BT474/100-2 cell lines displayed increased growth rate and invasiveness. The trastuzumab resistance in SKBR3/100-8 and BT474/100-2 was accompanied with activation of the Wnt/β-catenin signaling pathway. Further investigation found that Wnt3 overexpression played a key role toward the development of trastuzumab resistance. The expression of Wnt3 in trastuzumab-resistant cells increased nuclear expression of β-catenin and transactivated expression of EGFR. The increased Wnt3 in the trastuzumab-resistant cells also promoted a partial EMT-like transition (epithelial-to-mesenchymal transition); increased N-cadherin, Twist, Slug; and decreased E-cadherin. Knockdown of Wnt3 by siRNA restored cytoplasmic expression of β-catenin and decreased EGFR expression in trastuzumab-resistant cells. Furthermore, the EMT markers were decreased, E-cadherin was increased, and the cell invasiveness was inhibited in response to the Wnt3 downregulation. Conversely, SKBR3 cells which had been stably transfected with full-length Wnt3 exhibited EMT-like transition. The Wnt3 transfectants, SKBR3/Wnt3-7 and SKBR3/Wnt3-9, showed a significant decrease in E-cadherin and increase in N-cadherin, Twist, and Slug. The cells were less sensitive to trastuzumab than parental SKBR3 and vector-transfected cells. In summary, our data suggest that Wnt3 overexpression activates Wnt/β-catenin signaling pathway that leads to transactivation of EGFR and promotes EMT-like transition. This could be an important mechanism leading to trastuzumab resistance in HER2-overexpressing breast cancer cells. Mol Cancer Res; 10(12); 1597–606. ©2012 AACR.
Data from Significance of PELP1 in ER-Negative Breast Cancer Metastasis
Authors: Roy Sudipa , Chakravarty Dimple , Cortez Valerie , De Mukhopadhyay Keya , Bandyopadhyay Abhik , Ahn Jung-Mo , Raj Ganesh V. , Tekmal Rajeshwar R. , Sun LuZhe , Vadlamudi Ratna K.
Published: March 2024

Abstract
Breast cancer metastasis is a major clinical problem. The molecular basis of breast cancer progression to metastasis remains poorly understood. PELP1 is an estrogen receptor (ER) coregulator that has been implicated as a proto-oncogene whose expression is deregulated in metastatic breast tumors and whose expression is retained in ER-negative tumors. We examined the mechanism and significance of PELP1-mediated signaling in ER-negative breast cancer progression using two ER-negative model cells (MDA-MB-231 and 4T1 cells) that stably express PELP1-shRNA. These model cells had reduced PELP1 expression (75% of endogenous levels) and exhibited less propensity to proliferate in growth assays in vitro. PELP1 downregulation substantially affected migration of ER-negative cells in Boyden chamber and invasion assays. Using mechanistic studies, we found that PELP1 modulated expression of several genes involved in the epithelial mesenchymal transition (EMT), including MMPs, SNAIL, TWIST, and ZEB. In addition, PELP1 knockdown reduced the in vivo metastatic potential of ER-negative breast cancer cells and significantly reduced lung metastatic nodules in a xenograft assay. These results implicate PELP1 as having a role in ER-negative breast cancer metastasis, reveal novel mechanism of coregulator regulation of metastasis via promoting cell motility/EMT by modulating expression of genes, and suggest PELP1 may be a potential therapeutic target for metastatic ER-negative breast cancer. Mol Cancer Res; 10(1); 25–33. ©2011 AACR.
Data from Targeting Fatty Acid Oxidation to Promote Anoikis and Inhibit Ovarian Cancer Progression
Authors: Sawyer Brandon T. , Qamar Lubna , Yamamoto Tomomi M. , McMellen Alexandra , Watson Zachary L. , Richer Jennifer K. , Behbakht Kian , Schlaepfer Isabel R. , Bitler Benjamin G.
Published: March 2024

Abstract
Epithelial-derived high-grade serous ovarian cancer (HGSOC) is the deadliest gynecologic malignancy. Roughly 80% of patients are diagnosed with late-stage disease, which is defined by wide-spread cancer dissemination throughout the pelvic and peritoneal cavities. HGSOC dissemination is dependent on tumor cells acquiring the ability to resist anoikis (apoptosis triggered by cell detachment). Epithelial cell detachment from the underlying basement membrane or extracellular matrix leads to cellular stress, including nutrient deprivation. In this report, we examined the contribution of fatty acid oxidation (FAO) in supporting anoikis resistance. We examined expression Carnitine Palmitoyltransferase 1A (CPT1A) in a panel of HGSOC cell lines cultured in adherent and suspension conditions. With CPT1A knockdown cells, we evaluated anoikis by caspase 3/7 activity, cleaved caspase 3 immunofluorescence, flow cytometry, and colony formation. We assessed CPT1A-dependent mitochondrial activity and tested the effect of exogenous oleic acid on anoikis and mitochondrial activity. In a patient-derived xenograft model, we administered etomoxir, an FAO inhibitor, and/or platinum-based chemotherapy. CPT1A is overexpressed in HGSOC, correlates with poor overall survival, and is upregulated in HGSOC cells cultured in suspension. CPT1A knockdown promoted anoikis and reduced viability of cells cultured in suspension. HGSOC cells in suspension culture are dependent on CPT1A for mitochondrial activity. In a patient-derived xenograft model of HGSOC, etomoxir significantly inhibited tumor progression.
Implications:
Targeting FAO in HGSOC to promote anoikis and attenuate dissemination is a potential approach to promote a more durable antitumor response and improve patient outcomes.
Data from New Insight into the SDF-1/CXCR4 Axis in a Breast Carcinoma Model: Hypoxia-Induced Endothelial SDF-1 and Tumor Cell CXCR4 Are Required for Tumor Cell Intravasation
Authors: Jin Fengyan , Brockmeier Ulf , Otterbach Friedrich , Metzen Eric
Published: March 2024

Abstract
The SDF-1/CXCR4 axis has been implicated in breast cancer metastasis. In contrast to its well-established role in organ-specific homing and colonization of tumor cells, the involvement in intravasation, especially in a hypoxic environment, is still poorly understood. Initially, we detected both, the chemokine SDF-1 and its receptor CXCR4 in microvessels in invasive ductal cancer samples. To elucidate the role of the SDF-1/CXCR4 axis in vascular endothelium for tumor intravasation, we evaluated the effects of CXCR4 activation in human umbilical vein and dermal microvascular endothelial cells (HUVEC and HDMEC) and in cultured mammary carcinoma cells (MDA MB231, and MCF7). We observed an upregulation of SDF-1 and CXCR4 in HUVECs in hypoxia, which led to proliferation, migration, and tube formation. Hypoxia induced adhesion of tumor cells to endothelial cells and stimulated transendothelial migration. The effects of hypoxia were dependent on the activity of the transcription factor hypoxia-inducible factor. Adhesion to and migration through a HUVEC monolayer were significantly reduced by lentiviral inhibition of CXCR4 in breast carcinoma cells or treatment of endothelial cells with an anti-SDF-1 neutralizing antibody. These data show that the interaction of SDF-1 secreted by ECs with tumor cell CXCR4 is sufficient to stimulate transendothelial migration of the tumor cells. Our results suggest that the SDF-1/CXCR4 axis is important in angiogenesis and tumor cell intravasation. Because both proteins were readily identifiable in a significant fraction of human breast cancer samples by immunohistochemistry, CXCR4 may constitute a molecular target for therapy when both, SDF-1, and CXCR4 are expressed. Mol Cancer Res; 10(8); 1021–31. ©2012 AACR.
Data from Group I p21-Activated Kinases (PAKs) Promote Tumor Cell Proliferation and Survival through the AKT1 and Raf–MAPK Pathways
Authors: Menges Craig W. , Sementino Eleonora , Talarchek Jacqueline , Xu Jinfei , Chernoff Jonathan , Peterson Jeffrey R. , Testa Joseph R.
Published: March 2024

Abstract
Group I p21–activated kinases (PAK) are important effectors of the small GTPases Rac and Cdc42, which regulate cell motility/migration, survival, proliferation, and gene transcription. Hyperactivation of these kinases have been reported in many tumor types, making PAKs attractive targets for therapeutic intervention. PAKs are activated by growth factor–mediated signaling and are negatively regulated by the tumor suppressor neurofibromatosis type 2 (NF2)/Merlin. Thus, tumors characterized by NF2 inactivation would be expected to show hyperactivated PAK signaling. On the basis of this rationale, we evaluated the status of PAK signaling in malignant mesothelioma, an aggressive neoplasm that is resistant to current therapies and shows frequent inactivation of NF2. We show that group I PAKs are activated in most mesotheliomas and mesothelioma cell lines and that genetic or pharmacologic inhibition of PAKs is sufficient to inhibit mesothelioma cell proliferation and survival. We also identify downstream effectors and signaling pathways that may contribute mechanistically to PAK-related tumorigenesis. Specifically, we show that inhibition of PAK results in attenuation of AKT and Raf–MAPK signaling and decreased tumor cell viability. Collectively, these data suggest that pharmacologic inhibition of group I PAKs may have therapeutic efficacy in tumors characterized by PAK activation. Mol Cancer Res; 10(9); 1178–88. ©2012 AACR.
Data from Menin Promotes the Wnt Signaling Pathway in Pancreatic Endocrine Cells
Authors: Chen Gao , A Jingbo , Wang Min , Farley Steven , Lee Lung-Yi , Lee Lung-Ching , Sawicki Mark P.
Published: March 2024

Abstract
Menin is a tumor suppressor protein mutated in patients with multiple endocrine neoplasia type 1. We show that menin is essential for canonical Wnt/β-catenin signaling in cultured rodent islet tumor cells. In these cells, overexpression of menin significantly enhances TCF gene assay reporter activity in response to β-catenin activation. Contrastingly, inhibition of menin expression with Men1 siRNA decreases TCF reporter gene activity. Likewise, multiple endocrine neoplasia type 1 disease associated missense mutations of menin abrogate the ability to increase TCF reporter gene activity. We show that menin physically interacts with proteins involved in the canonical Wnt signaling pathway, including β-catenin, TCF3 (TCFL1), and weakly with TCF4 (TCFL2). Menin overexpression increases expression of the Wnt/β-catenin downstream target gene Axin2, which is associated with increased H3K4 trimethylation of the Axin2 gene promoter. Moreover, inhibition of menin expression by siRNA abrogates H3K4 trimethylation and Axin2 gene expression. Based on these studies, we hypothesized that Wnt signaling could inhibit islet cell proliferation because loss of menin function is thought to increase endocrine tumor cell proliferation. TGP61 rodent islet tumor cells treated with a glycogen synthase kinase 3β inhibitor that increases Wnt pathway signaling had decreased cell proliferation compared with vehicle-treated cells. Collectively, these data suggest that menin has an essential role in Wnt/β-catenin signaling through a mechanism that eventually affects histone trimethylation of the downstream target gene Axin2, and activation of Wnt/β-catenin signaling inhibits islet tumor cell proliferation. (Mol Cancer Res 2008;6(12):1894–907)
Data from Tumor Endothelial Cell–Mediated Antigen-Specific T-cell Suppression via the PD-1/PD-L1 Pathway
Authors: Taguchi Kazuhiro , Onoe Takashi , Yoshida Tomoaki , Yamashita Yoshinori , Tanaka Yuka , Ohdan Hideki
Published: March 2024

Abstract
Tumor endothelial cells (TEC) play multiple roles in the regional specialization of vascular structure and physiology. Because TECs in the tumor microenvironment come in contact with circulating immune cells, they might influence not only trafficking but also the antitumor cellular immune response. In a mouse tumor implantation model with B16 melanoma cells, TECs expressed MHC class II, costimulating molecules, and programmed death-ligand 1 (PD-L1), suggesting that they are antigen (Ag)-presenting cells with suppressive activity. Furthermore, TECs were able to take up and present tumor-derived ovalbumin (OVA) peptide on MHC class I molecules. In functional assays, B16-OVA tumor–derived TECs significantly suppressed the proliferation and Ag-specific cytotoxicity of OVA-specific CD8+ T cells relative to those of B16 tumor–derived TECs. This suppressive activity required cell–cell contact and was abrogated by PD-L1 blockade. TECs impaired proinflammatory cytokine production of CD8+ T cells, including IL2, TNFα, and IFNγ. B16-OVA tumor–derived TECs induced immunosuppressive CD4+ T cells that suppressed OVA-specific CD8+ T-cell proliferation via inhibitory cytokines, including IL10 and TGFβ. Deficiency of PD-L1 in TECs, but not in hematopoietic cells, impaired suppression and apoptosis of tumor-infiltrating CD8+ T cells, resulting in inhibition of tumor development in vivo model. These data suggest that TECs might regulate the immune response of tumor Ag–specific CD8+ T cells via the PD-1/PD-L1 pathway and induce immune suppressive CD4+ T cells in an Ag-specific manner, contributing to tumor immune evasion.
Implications:
The findings of this study might encourage the further development of novel anticancer therapies and strategies.
Data from Bacterial SOS Genes mucAB/umuDC Promote Mouse Tumors by Activating Oncogenes Nedd9/Aurkb via a miR-145 Sponge
Authors: Tanooka Hiroshi , Inoue Ayako , Takahashi Ryou-u , Tatsumi Kouichi , Fujikawa Kazuo , Nagao Tetsuji , Ishiai Masamichi , Chiwaki Fumiko , Aoyagi Kazuhiko , Sasaki Hiroki , Ochiya Takahiro
Published: March 2024

Abstract
The mechanism of cancer induction involves an aberrant expression of oncogenes whose functions can be controlled by RNAi with miRNA. Even foreign bacterial RNA may interfere with the expression of oncogenes. Here we show that bacterial plasmid mucAB and its Escherichia coli genomic homolog umuDC, carrying homologies that match the mouse anti-miR-145, sequestered the miR-145 function in mouse BALB 3T3 cells in a tetracycline (Tet)-inducible manner, activated oncogene Nedd9 and its downstream Aurkb, and further enhanced microcolony formation and cellular transformation as well as the short fragments of the bacterial gene containing the anti-miR-145 sequence. Furthermore, mucAB transgenic mice showed a 1.7-fold elevated tumor incidence compared with wild-type mice after treatments with 3-methylcolanthrene. However, the mutation frequency in intestinal stem cells of the mucAB transgenic mice was unchanged after treatment with X-rays or ethyl-nitrosourea, indicating that the target of mucAB/umuDC is the promotion stage in carcinogenesis.
Implications:
Foreign bacterial genes can exert oncogenic activity via RNAi, if endogenously expressed.
Visual Overview:
http://mcr.aacrjournals.org/content/molcanres/18/9/1271/F1.large.jpg.
Data from Luteinizing Hormone–Induced Up-Regulation of ErbB-2 Is Insufficient Stimulant of Growth and Invasion in Ovarian Cancer Cells
Authors: Warrenfeltz Susanne W. , Lott Stephen A. , Palmer Travis M. , Gray Judy C. , Puett David
Published: March 2024

Abstract
The effects of luteinizing hormone (LH), a gonadotropic hormone implicated in the development of ovarian cancer, are mediated by specific binding to its G protein–coupled receptor, the LH receptor (LHR). Activated LHR initiates second messenger responses, including cyclic AMP (cAMP) and inositol phosphate. Because cAMP increases expression of ErbB-2, a receptor tyrosine kinase whose overexpression in cancers correlates with poor survival, we hypothesized that LH may regulate ErbB-2 expression. Cell surface LHR expression in stable transformants of the ErbB-2–overexpressing ovarian cancer cell line SKOV3 was confirmed by PCR and whole-cell ligand binding studies. Second messenger accumulation in the LHR-expressing cells confirmed signaling through Gs and Gq. Western blots of total protein revealed that LHR introduction up-regulated ErbB-2 protein expression 2-fold and this was further up-regulated in a time- and dose-dependent manner in response to LH. Forskolin and 8Br-cAMP also up-regulated ErbB-2 in both LHR-expressing and mock-transfected cells, indicating that regulation of ErbB-2 is a cAMP-mediated event. Kinase inhibitor studies indicated the involvement of protein kinase A–mediated, protein kinase C–mediated, epidermal growth factor receptor–mediated, and ErbB-2–mediated mechanisms. The LH-induced up-regulation of ErbB-2 was insufficient to overcome the negative effects of LH on proliferation, invasion, and migration. A molecular signature for this nonaggressive phenotype was determined by Taqman array to include increased and decreased expression of genes encoding adhesion proteins and metalloproteinases, respectively. These data establish a role for LH and LHR in the regulation of ErbB-2 expression and suggest that, in some systems, ErbB-2 up-regulation alone is insufficient in producing a more aggressive phenotype. (Mol Cancer Res 2008;6(11):1775–85)