bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from GX15-070 (Obatoclax) Induces Apoptosis and Inhibits Cathepsin D- and L–Mediated Autophagosomal Lysis in Antiestrogen-Resistant Breast Cancer Cells
Authors: Schwartz-Roberts Jessica L. , Shajahan Ayesha N. , Cook Katherine L. , Wärri Anni , Abu-Asab Mones , Clarke Robert
Published: March 2024

Abstract
In estrogen receptor–positive (ER+) breast cancer cells, BCL2 overexpression contributes to antiestrogen resistance. Direct targeting of the antiapoptotic BCL2 members with GX15-070 (obatoclax), a BH3-mimetic currently in clinical development, is an attractive strategy to overcome antiestrogen resistance in some breast cancers. Recently, GX15-070 has been shown to induce both apoptosis and autophagy, yet the underlying cell death mechanisms have yet to be elucidated. Here, we show that GX15-070 is more effective in reducing the cell density of antiestrogen-resistant breast cancer cells versus sensitive cells and that this increased sensitivity of resistant cells to GX15-070 correlates with an accumulation of autophagic vacuoles. Formation of autophagosomes in GX15-070-treated cells was verified by changes in expression of the lipidation of microtubule-associated protein-1 light chain-3 and both confocal and transmission electron microscopy. While GX15-070 treatment promotes autophagic vacuole and autolysosome formation, p62/SQSTM1, a marker for autophagic degradation, levels accumulate. Moreover, GX15-070 exposure leads to a reduction in cathepsin D (CTSD) and L (CTSL1) protein expression that would otherwise digest autolysosome cargo. Thus, GX15-070 has dual roles in promoting cell death: (i) directly inhibiting antiapoptotic BCL2 family members, thereby inducing apoptosis; and (ii) inhibiting downstream CTSD and CTSL1 protein expression to limit the ability of cells to use degraded material to fuel cellular metabolism and restore homeostasis. Our data highlight a new mechanism of GX15-070-induced cell death that could be used to design novel therapeutic interventions for antiestrogen resistant breast cancer. Mol Cancer Ther; 12(4); 448–59. ©2013 AACR.
Data from Crizotinib, a c-Met Inhibitor, Prevents Metastasis in a Metastatic Uveal Melanoma Model
Authors: Surriga Oliver , Rajasekhar Vinagolu K. , Ambrosini Grazia , Dogan Yildrim , Huang Ruimin , Schwartz Gary K.
Published: March 2024

Abstract
Uveal melanoma is the most common primary intraocular malignant tumor in adults and half of the primary tumors will develop fatal metastatic disease to the liver and the lung. Crizotinib, an inhibitor of c-Met, anaplastic lymphoma kinase (ALK), and ROS1, inhibited the phosphorylation of the c-Met receptor but not of ALK or ROS1 in uveal melanoma cells and tumor tissue. Consequently, migration of uveal melanoma cells was suppressed in vitro at a concentration associated with the specific inhibition of c-Met phosphorylation. This effect on cell migration could be recapitulated with siRNA specific to c-Met but not to ALK or ROS1. Therefore, we developed a uveal melanoma metastatic mouse model with EGFP–luciferase-labeled uveal melanoma cells transplanted by retro-orbital injections to test the effect of crizotinib on metastasis. In this model, there was development of melanoma within the eye and also metastases to the liver and lung at 7 weeks after the initial transplantation. When mice were treated with crizotinib starting 1 week after the transplantation, we observed a significant reduction in the development of metastases as compared with untreated control sets. These results indicate that the inhibition of c-Met activity alone may be sufficient to strongly inhibit metastasis of uveal melanoma from forming, suggesting crizotinib as a potential adjuvant therapy for patients with primary uveal melanoma who are at high risk for the development of metastatic disease. Mol Cancer Ther; 12(12); 2817–26. ©2013 AACR.
Data from Targeting Olfactomedin-like 3 Inhibits Tumor Growth by Impairing Angiogenesis and Pericyte Coverage
Authors: Miljkovic-Licina Marijana , Hammel Philippe , Garrido-Urbani Sarah , Lee Boris P.-L. , Meguenani Mehdi , Chaabane Chiraz , Bochaton-Piallat Marie-Luce , Imhof Beat A.
Published: March 2024

Abstract
Antiangiogenic drugs have been used as anticancer agents to target tumor endothelial cells or pericytes. Because of limited efficacy of the current monotherapies, there is a strong demand for the dual targeting of endothelial cells and pericytes. Here, we identify Olfactomedin-like 3 (Olfml3) as a novel proangiogenic cue within the tumor microenvironment. Tumor-derived Olfml3 is produced by both tumor endothelial cells and accompanying pericytes and deposited in the perivascular compartment. Blockade of Olfml3 by anti-Olfml3 antibodies is highly effective in reducing tumor vascularization, pericyte coverage, and tumor growth. In vitro, Olfml3 targeting is sufficient to inhibit endothelioma cell migration and sprouting. Olfml3 alone or through binding to BMP4 enhances the canonical SMAD1/5/8 signaling pathway required for BMP4-induced angiogenesis. Therefore, Olfml3 blockade provides a novel strategy to control tumor growth by targeting two distinct cell types within the tumor microenvironment using a single molecule. Mol Cancer Ther; 11(12); 2588–99. ©2012 AACR.
Data from Prognostic Role of Lemur Tyrosine Kinase-3 Germline Polymorphisms in Adjuvant Gastric Cancer in Japan and the United States
Authors: Wakatsuki Takeru , LaBonte Melissa J. , Bohanes Pierre O. , Zhang Wu , Yang Dongyun , Azuma Mizutomo , Barzi Afsaneh , Ning Yan , Loupakis Fotios , Saadat Siamak , Volz Nico , Stintzing Sebastian , El-Khoueiry Rita , Koizumi Wasaburo , Watanabe Masahiko , Shah Manish , Stebbing Justin , Giamas Georgios , Lenz Heinz-Josef
Published: March 2024

Abstract
Lemur tyrosine kinase-3 (LMTK3) was recently identified as an estrogen receptor (ER)-α modulator related to endocrine therapy resistance, and its polymorphisms rs9989661 (T>C) T/T genotype and rs8108419 (G>A) G/G or A/G genotype predicted improved outcomes in breast cancer. Because different predominant ER distributions link to breast and gastric cancer and little is known of the prognostic role of LMTK3 in gastric cancer, this study was carried out to clarify the prognostic role of these polymorphisms in gastric cancer. One-hundred and sixty-nine Japanese and 137 U.S. patients with localized gastric adenocarcinoma were enrolled. Genomic DNA was extracted from blood or tissue, and all samples were analyzed by PCR-based direct DNA sequencing. Overall, these polymorphisms were not associated with survival in both cohorts. When gender was considered, in multivariate analysis, harboring rs9989661 T/T genotype was associated with disease-free survival [HR, 4.37; 95% confidence interval (CI), 2.08–9.18; P < 0.0001] and overall survival (OS; HR, 3.69; 95% CI, 1.65–8.24; P = 0.0014) in the Japanese males and time to recurrence (HR, 7.29; 95% CI, 1.07–49.80; P = 0.043) in the U.S. females. Meanwhile, harboring rs8108419 G/G genotype was associated with OS in the Japanese females (HR, 3.04; 95% CI, 1.08–8.56; P = 0.035) and the U.S. males (HR, 3.39; 95% CI, 1.31–8.80; P = 0.012). The prognostic role of these polymorphisms may be negative in gastric cancer. These findings suggest that the estrogen pathway may play a prognostic role in patients with gastric cancer but this may be dependent on the regional differences both in physiology and genetic alterations of gastric cancer. Mol Cancer Ther; 12(10); 2261–72. ©2013 AACR.
Data from The Tyrosine Kinase Inhibitor E-3810 Combined with Paclitaxel Inhibits the Growth of Advanced-Stage Triple-Negative Breast Cancer Xenografts
Authors: Bello Ezia , Taraboletti Giulia , Colella Gennaro , Zucchetti Massimo , Forestieri Daniele , Licandro Simonetta A. , Berndt Alexander , Richter Petra , D'Incalci Maurizio , Cavalletti Ennio , Giavazzi Raffaella , Camboni Gabriella , Damia Giovanna
Published: March 2024

Abstract
E-3810 is a novel small molecule that inhibits VEGF receptor-1, -2, and -3 and fibroblast growth factor receptor-1 tyrosine kinases at nmol/L concentrations currently in phase clinical II. In preclinical studies, it had a broad spectrum of antitumor activity when used as monotherapy in a variety of human xenografts. We here investigated the activity of E-3810 combined with different cytotoxic agents in a MDA-MB-231 triple-negative breast cancer xenograft model. The molecule could be safely administered with 5-fluorouracil, cisplatin, and paclitaxel. The E-3810–paclitaxel combination showed a striking activity with complete, lasting tumor regressions; the antitumor activity of the combination was also confirmed in another triple-negative breast xenograft, MX-1. The activity was superior to that of the combinations paclitaxel+brivanib and paclitaxel+sunitinib. Pharmacokinetics studies suggest that the extra antitumor activity of the combination is not due to higher paclitaxel tumor levels, which in fact were lower in mice pretreated with all three kinase inhibitors, and the paclitaxel plasma levels excluded reduced drug availability. Pharmacodynamic studies showed that E-3810, brivanib, and sunitinib given as single agents or in combination with paclitaxel reduced the number of vessels, but did not modify vessel maturation. Reduced tumor collagen IV and increased plasma collagen IV, associated with increased matrix metalloproteinases (MMP), particularly host MMP-9, indicate a proteolytic remodeling of the extracellular matrix caused by E-3810 that in conjunction with the cytotoxic effect of paclitaxel on the tumor cells (caspase-3/7 activity) may contribute to the striking activity of their combination. These data support the therapeutic potential of combining E-3810 with conventional chemotherapy. Mol Cancer Ther; 12(2); 131–40. ©2012 AACR.
Data from Genome and Transcriptome Sequencing in Prospective Metastatic Triple-Negative Breast Cancer Uncovers Therapeutic Vulnerabilities
Authors: Craig David W. , O'Shaughnessy Joyce A. , Kiefer Jeffrey A. , Aldrich Jessica , Sinari Shripad , Moses Tracy M. , Wong Shukmei , Dinh Jennifer , Christoforides Alexis , Blum Joanne L. , Aitelli Cristi L. , Osborne Cynthia R. , Izatt Tyler , Kurdoglu Ahmet , Baker Angela , Koeman Julie , Barbacioru Catalin , Sakarya Onur , De La Vega Francisco M. , Siddiqui Asim , Hoang Linh , Billings Paul R. , Salhia Bodour , Tolcher Anthony W. , Trent Jeffrey M. , Mousses Spyro , Von Hoff Daniel , Carpten John D.
Published: March 2024

Abstract
Triple-negative breast cancer (TNBC) is characterized by the absence of expression of estrogen receptor, progesterone receptor, and HER-2. Thirty percent of patients recur after first-line treatment, and metastatic TNBC (mTNBC) has a poor prognosis with median survival of one year. Here, we present initial analyses of whole genome and transcriptome sequencing data from 14 prospective mTNBC. We have cataloged the collection of somatic genomic alterations in these advanced tumors, particularly those that may inform targeted therapies. Genes mutated in multiple tumors included TP53, LRP1B, HERC1, CDH5, RB1, and NF1. Notable genes involved in focal structural events were CTNNA1, PTEN, FBXW7, BRCA2, WT1, FGFR1, KRAS, HRAS, ARAF, BRAF, and PGCP. Homozygous deletion of CTNNA1 was detected in 2 of 6 African Americans. RNA sequencing revealed consistent overexpression of the FOXM1 gene when tumor gene expression was compared with nonmalignant breast samples. Using an outlier analysis of gene expression comparing one cancer with all the others, we detected expression patterns unique to each patient's tumor. Integrative DNA/RNA analysis provided evidence for deregulation of mutated genes, including the monoallelic expression of TP53 mutations. Finally, molecular alterations in several cancers supported targeted therapeutic intervention on clinical trials with known inhibitors, particularly for alterations in the RAS/RAF/MEK/ERK and PI3K/AKT/mTOR pathways. In conclusion, whole genome and transcriptome profiling of mTNBC have provided insights into somatic events occurring in this difficult to treat cancer. These genomic data have guided patients to investigational treatment trials and provide hypotheses for future trials in this irremediable cancer. Mol Cancer Ther; 12(1); 104–16. ©2012 AACR.
Data from Evaluating the Therapeutic Potential of a Non-Natural Nucleotide That Inhibits Human Ribonucleotide Reductase
Authors: Ahmad Md. Faiz , Wan Qun , Jha Shalini , Motea Edward , Berdis Anthony , Dealwis Chris
Published: March 2024

Abstract
Human ribonucleotide reductase (hRR) is the key enzyme involved in de novo dNTP synthesis and thus represents an important therapeutic target against hyperproliferative diseases, most notably cancer. The purpose of this study was to evaluate the ability of non-natural indolyl-2′-deoxynucleoside triphosphates to inhibit the activity of hRR. The structural similarities of these analogues with dATP predicted that they would inhibit hRR activity by binding to its allosteric sites. In silico analysis and in vitro characterization identified one particular analogue designated as 5-nitro-indolyl-2′-deoxyribose triphosphate (5-NITP) that inhibits hRR. 5-NITP binding to hRR was determined by isothermal titration calorimetry. X-ray crystal structure of 5-NITP bound to RR1 was determined. Cell-based studies showed the anti-cancer effects of the corresponding non-natural nucleoside against leukemia cells. 5-NITP binds to hRR with micromolar affinity. Binding does not induce hexamerization of hRR1 like dATP, the native allosteric inhibitor of hRR that binds with high affinity to the A-site. The X-ray crystal structure of Saccharomyces cerevisiae RR1-5-NITP (ScRR1-5-NITP) complex determined to 2.3 Å resolution shows that 5-NITP does not bind to the A-site but rather at the S-site. Regardless, 5-nitro-indolyl-2′-deoxynucleoside (5-NIdR) produces cytostatic and cytotoxic effects against human leukemia cells by altering cell-cycle progression. Our studies provide useful insights toward developing new inhibitors with improved potency and efficacy against hRR. Mol Cancer Ther; 11(10); 2077–86. ©2012 AACR.
Data from Catalase Abrogates β-Lapachone–Induced PARP1 Hyperactivation–Directed Programmed Necrosis in NQO1-Positive Breast Cancers
Authors: Bey Erik A. , Reinicke Kathryn E. , Srougi Melissa C. , Varnes Marie , Anderson Vernon E. , Pink John J. , Li Long Shan , Patel Malina , Cao Lifen , Moore Zachary , Rommel Amy , Boatman Michael , Lewis Cheryl , Euhus David M. , Bornmann William G. , Buchsbaum Donald J. , Spitz Douglas R. , Gao Jinming , Boothman David A.
Published: March 2024

Abstract
Improving patient outcome by personalized therapy involves a thorough understanding of an agent's mechanism of action. β-Lapachone (clinical forms, Arq501/Arq761) has been developed to exploit dramatic cancer-specific elevations in the phase II detoxifying enzyme NAD(P)H:quinone oxidoreductase (NQO1). NQO1 is dramatically elevated in solid cancers, including primary and metastatic [e.g., triple-negative (ER−, PR−, Her2/Neu−)] breast cancers. To define cellular factors that influence the efficacy of β-lapachone using knowledge of its mechanism of action, we confirmed that NQO1 was required for lethality and mediated a futile redox cycle where ∼120 moles of superoxide were formed per mole of β-lapachone in 2 minutes. β-Lapachone induced reactive oxygen species (ROS), stimulated DNA single-strand break-dependent poly(ADP-ribose) polymerase-1 (PARP1) hyperactivation, caused dramatic loss of essential nucleotides (NAD+/ATP), and elicited programmed necrosis in breast cancer cells. Although PARP1 hyperactivation and NQO1 expression were major determinants of β-lapachone–induced lethality, alterations in catalase expression, including treatment with exogenous enzyme, caused marked cytoprotection. Thus, catalase is an important resistance factor and highlights H2O2 as an obligate ROS for cell death from this agent. Exogenous superoxide dismutase enhanced catalase-induced cytoprotection. β-Lapachone–induced cell death included apoptosis-inducing factor (AIF) translocation from mitochondria to nuclei, TUNEL+ staining, atypical PARP1 cleavage, and glyceraldehyde 3-phosphate dehydrogenase S-nitrosylation, which were abrogated by catalase. We predict that the ratio of NQO1:catalase activities in breast cancer versus associated normal tissue are likely to be the major determinants affecting the therapeutic window of β-lapachone and other NQO1 bioactivatable drugs. Mol Cancer Ther; 12(10); 2110–20. ©2013 AACR.
Data from Inhibition of STAT3 Signaling Pathway by Nitidine Chloride Suppressed the Angiogenesis and Growth of Human Gastric Cancer
Authors: Chen Jing , Wang Jieqiong , Lin Lei , He Lijun , Wu Yuanyuan , Zhang Li , Yi Zhengfang , Chen Yihua , Pang Xiufeng , Liu Mingyao
Published: March 2024

Abstract
STAT3 has been strongly implicated in human malignancies, and constitutive activation of STAT3 serves a crucial role in cell survival, angiogenesis, immune evasion, and inflammation. In this study, we showed that nitidine chloride, a natural phytochemical alkaloid derived from Zanthoxylum nitidum (Roxb) DC, exerts potent anticancer activity through STAT3 signaling cascade. Nitidine chloride dose dependently suppressed VEGF-induced endothelial cell proliferation, migration, and tubular structure formation in vitro and dramatically reduced VEGF-triggered neovascularization in mouse cornea and Matrigel plugs in vivo. This angiogenesis inhibition mediated by nitidine chloride was well interpreted by the suppression of Janus kinase 2/STAT3 signaling and STAT3 DNA-binding activity in endothelial cells. Furthermore, nitidine chloride suppressed the constitutively activated STAT3 protein, its DNA-binding activity, and the expression of STAT3-dependent target genes, including cyclin D1, Bcl-xL, and VEGF in human gastric cancer cells. Consistent with the earlier findings, nitidine chloride inhibited gastric tumor cell growth and induced tumor cell apoptosis in vitro and effectively suppressed the volume, weight, and microvessel density of human SGC-7901 gastric solid tumors (n = 8) at a dosage of 7 mg/kg/d (intraperitoneal injection). Immunohistochemistry and Western blot analysis further revealed that the expression of STAT3, CD31, and VEGF protein in xenografts was remarkably decreased by the alkaloid. Taken together, we propose that nitidine chloride is a promising anticancer drug candidate as a potent STAT3 signaling inhibitor. Mol Cancer Ther; 11(2); 277–87. ©2011 AACR.
Data from Long-term Tumor Regression Induced by an Antibody–Drug Conjugate That Targets 5T4, an Oncofetal Antigen Expressed on Tumor-Initiating Cells
Authors: Sapra Puja , Damelin Marc , DiJoseph John , Marquette Kimberly , Geles Kenneth G. , Golas Jonathon , Dougher Maureen , Narayanan Bitha , Giannakou Andreas , Khandke Kiran , Dushin Russell , Ernstoff Elana , Lucas Judy , Leal Mauricio , Hu George , O'Donnell Christopher J. , Tchistiakova Lioudmila , Abraham Robert T. , Gerber Hans-Peter
Published: March 2024

Abstract
Antibody–drug conjugates (ADC) represent a promising therapeutic modality for the clinical management of cancer. We sought to develop a novel ADC that targets 5T4, an oncofetal antigen expressed on tumor-initiating cells (TIC), which comprise the most aggressive cell population in the tumor. We optimized an anti-5T4 ADC (A1mcMMAF) by sulfydryl-based conjugation of the humanized A1 antibody to the tubulin inhibitor monomethylauristatin F (MMAF) via a maleimidocaproyl linker. A1mcMMAF exhibited potent in vivo antitumor activity in a variety of tumor models and induced long-term regressions for up to 100 days after the last dose. Strikingly, animals showed pathologic complete response in each model with doses as low as 3 mg antibody/kg dosed every 4 days. In a non–small cell lung cancer patient-derived xenograft model, in which 5T4 is preferentially expressed on the less differentiated tumor cells, A1mcMMAF treatment resulted in sustained tumor regressions and reduced TIC frequency. These results highlight the potential of ADCs that target the most aggressive cell populations within tumors, such as TICs. In exploratory safety studies, A1mcMMAF exhibited no overt toxicities when administered to cynomolgus monkeys at doses up to 10 mg antibody/kg/cycle × 2 and displayed a half-life of 5 days. The preclinical efficacy and safety data established a promising therapeutic index that supports clinical testing of A1mcMMAF. Mol Cancer Ther; 12(1); 38–47. ©2012 AACR.
Data from The Cannabinoid WIN 55,212-2 Decreases Specificity Protein Transcription Factors and the Oncogenic Cap Protein eIF4E in Colon Cancer Cells
Authors: Sreevalsan Sandeep , Safe Stephen
Published: March 2024

Abstract
2,3-Dihydro-5-methyl-3-([morpholinyl]methyl)pyrollo(1,2,3-de)-1,4-benzoxazinyl]-[1-naphthaleny]methanone [WIN 55,212-2, (WIN)] is a synthetic cannabinoid that inhibits RKO, HT-29, and SW480 cell growth, induced apoptosis, and downregulated expression of survivin, cyclin D1, EGF receptor (EGFR), VEGF, and its receptor (VEGFR1). WIN also decreased expression of specificity protein (Sp) transcription factors Sp1, Sp3, and Sp4, and this is consistent with the observed downregulation of the aforementioned Sp-regulated genes. In addition, we also observed by RNA interference (RNAi) that the oncogenic cap protein eIF4E was an Sp-regulated gene also downregulated by WIN in colon cancer cells. WIN-mediated repression of Sp proteins was not affected by cannabinoid receptor antagonists or by knockdown of the receptor but was attenuated by the phosphatase inhibitor sodium orthovanadate or by knockdown of protein phosphatase 2A (PP2A). WIN-mediated repression of Sp1, Sp3, and Sp4 was due to PP2A-dependent downregulation of microRNA-27a (miR-27a) and induction of miR-27a–regulated ZBTB10, which has previously been characterized as an “Sp repressor.” The results show that the anticancer activity of WIN is due, in part, to PP2A-dependent disruption of miR-27a:ZBTB10 and ZBTB10-mediated repression of Sp transcription factors and Sp-regulated genes, including eIF4E. Mol Cancer Ther; 12(11); 2483–93. ©2013 AACR.
Data from Hsp90 Inhibitors Promote p53-Dependent Apoptosis through PUMA and Bax
Authors: He Kan , Zheng Xingnan , Zhang Lin , Yu Jian
Published: March 2024

Abstract
Hsp90 is widely overexpressed in cancer cells and believed to be essential for the maintenance of malignant phenotypes. Targeting Hsp90 by small molecules has shown promise in solid and hematologic malignancies, which likely involves degradation of client oncoproteins in a cell-type–specific manner. In this study, we found that structurally unrelated Hsp90 inhibitors induce DNA damage and apoptosis via p53-dependent induction of PUMA, which indirectly triggers Bax activation and mitochondrial dysfunction in colon cancer cells. Deficiency in PUMA, BAX, or p53, at lesser extent, abrogated 17-allylamino-17-demethoxygeldanamycin (17-AAG)-induced apoptosis and mitochondrial dysfunction, and enhanced clonogenic cell survival. Furthermore, suppression of p53-dependent p21 induction or enhanced p53 activation synergized with 17-AAG to induce PUMA-dependent apoptosis. Finally, PUMA was found to mediate apoptotic and therapeutic responses to the 17-AAG analog 17-DMAG in xenografts. These results show an important role of the p53/PUMA/Bax axis in Hsp90 inhibitor–induced killing of p53 wild-type cells, and have important implications for their clinical applications. Mol Cancer Ther; 12(11); 2559–68. ©2013 AACR.
Data from Effective Targeting of Hedgehog Signaling in a Medulloblastoma Model with PF-5274857, a Potent and Selective Smoothened Antagonist That Penetrates the Blood–Brain Barrier
Authors: Rohner Allison , Spilker Mary E. , Lam Justine L. , Pascual Bernadette , Bartkowski Darian , Li Qing John , Yang Amy H. , Stevens Greg , Xu Meirong , Wells Peter A. , Planken Simon , Nair Sajiv , Sun Shaoxian
Published: March 2024

Abstract
Inhibition of the Smoothened (Smo) represents a promising therapeutic strategy for treating malignant tumors that are dependent on the Hedgehog (Hh) signaling pathway. PF-5274857 is a novel Smo antagonist that specifically binds to Smo with a Ki of 4.6 ± 1.1 nmol/L and completely blocks the transcriptional activity of the downstream gene Gli1 with an IC50 of 2.7 ± 1.4 nmol/L in cells. This Smo antagonist showed robust antitumor activity in a mouse model of medulloblastoma with an in vivo IC50 of 8.9 ± 2.6 nmol/L. The downregulation of Gli1 is closely linked to the tumor growth inhibition in patched+/− medulloblastoma mice. Mathematical analysis of the relationship between the drug's pharmacokinetics and Gli1 pharmacodynamics in patched+/− medulloblastoma tumor models yielded similar tumor and skin Gli1 IC50 values, suggesting that skin can be used as a surrogate tissue for the measurement of tumor Gli1 levels. In addition, PF-5274857 was found to effectively penetrate the blood–brain barrier and inhibit Smo activity in the brain of primary medulloblastoma mice, resulting in improved animal survival rates. The brain permeability of PF-5274857 was also confirmed and quantified in nontumor-bearing preclinical species with an intact blood–brain barrier. PF-5274857 was orally available and metabolically stable in vivo. These findings suggest that PF-5274857 is a potentially attractive clinical candidate for the treatment of tumor types including brain tumors and brain metastasis driven by an activated Hh pathway. Mol Cancer Ther; 11(1); 57–65. ©2011 AACR.
Data from Biological Characterization of TAK-901, an Investigational, Novel, Multitargeted Aurora B Kinase Inhibitor
Authors: Farrell Pamela , Shi Lihong , Matuszkiewicz Jennifer , Balakrishna Deepika , Hoshino Takashi , Zhang Lilly , Elliott Sarah , Fabrey Robyn , Lee Bumsup , Halkowycz Petro , Sang BiChing , Ishino Seigo , Nomura Toshiyuki , Teratani Mika , Ohta Yoshikazu , Grimshaw Charles , Paraselli Bheema , Satou Takashi , de Jong Ron
Published: March 2024

Abstract
Protein kinases Aurora A, B, and C play essential roles during mitosis and cell division, are frequently elevated in cancer, and represent attractive targets for therapeutic intervention. TAK-901 is an investigational, multitargeted Aurora B kinase inhibitor derived from a novel azacarboline kinase hinge-binder chemotype. TAK-901 exhibited time-dependent, tight-binding inhibition of Aurora B, but not Aurora A. Consistent with Aurora B inhibition, TAK-901 suppressed cellular histone H3 phosphorylation and induced polyploidy. In various human cancer cell lines, TAK-901 inhibited cell proliferation with effective concentration values from 40 to 500 nmol/L. Examination of a broad panel of kinases in biochemical assays revealed inhibition of multiple kinases. However, TAK-901 potently inhibited only a few kinases other than Aurora B in intact cells, including FLT3 and FGFR2. In rodent xenografts, TAK-901 exhibited potent activity against multiple human solid tumor types, and complete regression was observed in the ovarian cancer A2780 model. TAK-901 also displayed potent activity against several leukemia models. In vivo biomarker studies showed that TAK-901 induced pharmacodynamic responses consistent with Aurora B inhibition and correlating with retention of TAK-901 in tumor tissue. These preclinical data highlight the therapeutic potential of TAK-901, which has entered phase I clinical trials in patients within a diverse range of cancers. Mol Cancer Ther; 12(4); 460–70. ©2013 AACR.
Data from Retinoid-Regulated FGF8f Secretion by Osteoblasts Bypasses Retinoid Stimuli to Mediate Granulocytic Differentiation of Myeloid Leukemia Cells
Authors: Chaudhry Parvesh , Yang Xiaochun , Wagner Michael , Jong Ambrose , Wu Lingtao
Published: March 2024

Abstract
Signaling from the human hematopoietic stem cell (HSC) niche formed by osteoblastic cells regulates hematopoiesis. We previously found that retinoic acid receptor alpha (RARα), a transcription factor activated by retinoic acid (RA), mediates both granulocytic and osteoblastic differentiation. This effect depends on decreased phosphorylation of serine 77 of RARα (RARαS77) by the cyclin-dependent kinase-activating kinase (CAK) complex, a key cell-cycle regulator. In this article, we report that, by suppressing CAK phosphorylation of RARα, RA induces FGF8f to mediate osteosarcoma U2OS cell differentiation in an autocrine manner. By contrast, paracrine FGF8f secreted into osteoblast-conditioned medium by U2OS cells transduced with FGF8f or a phosphorylation-defective RARαS77 mutant, RARαS77A, bypasses RA stimuli to cross-mediate granulocytic differentiation of different types of human leukemic myeloblasts and normal primitive hematopoietic CD34+ cells, possibly through modulating mitogen-activated protein kinase (MAPK) pathways. Further experiments using recombinant human FGF8f (rFGF8f) stimuli, antibody neutralization, and peptide blocking showed that paracrine FGF8f is required for mediating terminal leukemic myeloblast differentiation. These studies indicate a novel regulatory mechanism of granulocytic differentiation instigated by RA from the HSC niche, which links loss of CAK phosphorylation of RARα with paracrine FGF8f-mediated MAPK signaling to mediate leukemic myeloblast differentiation in the absence of RA. Therefore, these findings provide a compelling molecular rationale for further investigation of paracrine FGF8f regulation, with the intent of devising HSC niche-based FGF8f therapeutics for myeloid leukemia, with or without RA-resistance. Mol Cancer Ther; 11(2); 267–76. ©2011 AACR.
Data from Impact of Intrinsic Affinity on Functional Binding and Biological Activity of EGFR Antibodies
Authors: Zhou Yu , Goenaga Anne-Laure , Harms Brian D. , Zou Hao , Lou Jianlong , Conrad Fraser , Adams Gregory P. , Schoeberl Birgit , Nielsen Ulrik B. , Marks James D.
Published: March 2024

Abstract
Aberrant expression and activation of EGF receptor (EGFR) has been implicated in the development and progression of many human cancers. As such, targeted therapeutic inhibition of EGFR, for example by antibodies, is a promising anticancer strategy. The overall efficacy of antibody therapies results from the complex interplay between affinity, valence, tumor penetration and retention, and signaling inhibition. To gain better insight into this relationship, we studied a panel of EGFR single-chain Fv (scFv) antibodies that recognize an identical epitope on EGFR but bind with intrinsic monovalent affinities varying by 280-fold. The scFv were converted to Fab and IgG formats, and investigated for their ability to bind EGFR, compete with EGF binding, and inhibit EGF-mediated downstream signaling and proliferation. We observed that the apparent EGFR-binding affinity for bivalent IgG plateaus at intermediate values of intrinsic affinity of the cognate Fab, leading to a biphasic curve describing the ratio of IgG to Fab affinity. Mathematical modeling of antibody–receptor binding indicated that the biphasic effect results from nonequilibrium assay limitations. This was confirmed by further observation that the potency of EGF competition for antibody binding to EGFR improved with both intrinsic affinity and antibody valence. Similarly, both higher intrinsic affinity and bivalent binding improved the potency of antibodies in blocking cellular signaling and proliferation. Overall, our work indicates that higher intrinsic affinity combined with bivalent binding can achieve avidity that leads to greater in vitro potency of antibodies, which may translate into greater therapeutic efficacy. Mol Cancer Ther; 11(7); 1467–76. ©2012 AACR.
Data from BAY 80-6946 Is a Highly Selective Intravenous PI3K Inhibitor with Potent p110α and p110δ Activities in Tumor Cell Lines and Xenograft Models
Authors: Liu Ningshu , Rowley Bruce R. , Bull Cathy O. , Schneider Claudia , Haegebarth Andrea , Schatz Christoph A. , Fracasso Paul R. , Wilkie Dean P. , Hentemann Martin , Wilhelm Scott M. , Scott William J. , Mumberg Dominik , Ziegelbauer Karl
Published: March 2024

Abstract
Because of the complexity derived from the existence of various phosphoinositide 3-kinase (PI3K) isoforms and their differential roles in cancers, development of PI3K inhibitors with differential pharmacologic and pharmacokinetic profiles would allow best exploration in different indications, combinations, and dosing regimens. Here, we report BAY 80-6946, a highly selective and potent pan-class I PI3K inhibitor with sub-nanomolar IC50s against PI3Kα and PI3Kδ. BAY 80-6946 exhibited preferential inhibition (about 10-fold) of AKT phosphorylation by PI3Kα compared with PI3Kβ in cells. BAY 80-6946 showed superior antitumor activity (>40-fold) in PIK3CA mutant and/or HER2 overexpression as compared with HER2-negative and wild-type PIK3CA breast cancer cell lines. In addition, BAY 80-6946 revealed potent activity to induce apoptosis in a subset of tumor cells with aberrant activation of PI3K as a single agent. In vivo, single intravenous administration of BAY 80-6946 exhibited higher exposure and prolonged inhibition of pAKT levels in tumors versus plasma. BAY 80-6946 is efficacious in tumors with activated PI3K when dosed either continuously or intermittently. Thus, BAY 80-6946 induced 100% complete tumor regression when dosed as a single agent every second day in rats bearing HER2-amplified and PIK3CA-mutated KPL4 breast tumors. In combination with paclitaxel, weekly dosing of BAY 80-6946 is sufficient to reach sustained response in all animals bearing patient-derived non–small cell lung cancer xenografts, despite a short plasma elimination half-life (1 hour) in mice. Thus, BAY 80-6946 is a promising agent with differential pharmacologic and pharmacokinetic properties for the treatment of PI3K-dependent human tumors. Mol Cancer Ther; 12(11); 2319–30. ©2013 AACR.
Data from Afatinib Prolongs Survival Compared with Gefitinib in an Epidermal Growth Factor Receptor-Driven Lung Cancer Model
Authors: Ninomiya Takashi , Takigawa Nagio , Ichihara Eiki , Ochi Nobuaki , Murakami Toshi , Honda Yoshihiro , Kubo Toshio , Minami Daisuke , Kudo Kenichiro , Tanimoto Mitsune , Kiura Katsuyuki
Published: March 2024

Abstract
An irreversible ErbB family blocker is expected to inhibit tumors with activating epidermal growth factor receptor (EGFR) mutations more strongly than reversible EGFR tyrosine kinase inhibitors and to overcome acquired resistance to the T790M secondary mutation. Eleven-week-old transgenic mice with Egfr exon 19 deletion mutation were treated with afatinib, gefitinib, or vehicle for 4 weeks. All mice were sacrificed at 15 weeks of age, and the number of superficial left lung tumors with a long axis exceeding 1 mm was counted. The afatinib-treated group had significantly fewer tumors than the vehicle group (P < 0.01) and tended to have fewer tumors than the gefitinib-treated group (P = 0.06). Pathologically, gefitinib-treated mice had clearer, more nodular tumors than afatinib-treated mice. Immunoblotting showed that afatinib suppressed not only pEGFR but also pHER2, and induced apoptosis for longer periods than gefitinib. Subsequently, when each drug was administered 5 days per week until death, afatinib significantly enhanced mouse survival compared with gefitinib (median survival time: 456 days vs. 376.5 days; log-rank test, P < 0.01). Finally, the combination of afatinib with bevacizumab was found to be superior to either drug alone in exon 19 deletion/T790M and L858R/T790M xenograft tumors. Overall, afatinib was more potent than gefitinib in tumors harboring an exon 19 deletion mutation, and the combination of afatinib with bevacizumab efficiently suppressed tumors harboring the T790M secondary mutation. Mol Cancer Ther; 12(5); 589–97. ©2013 AACR.
Data from Sym004, a Novel Anti-EGFR Antibody Mixture, Augments Radiation Response in Human Lung and Head and Neck Cancers
Authors: Huang Shyhmin , Peet Chimera R. , Saker Jarob , Li Chunrong , Armstrong Eric A. , Kragh Michael , Pedersen Mikkel W. , Harari Paul M.
Published: March 2024

Abstract
Sym004 represents a novel EGF receptor (EGFR)-targeting approach comprising a mixture of two anti-EGFR antibodies directed against distinct epitopes of EGFR. In contrast with single anti-EGFR antibodies, Sym004 induces rapid and highly efficient degradation of EGFR. In the current study, we examine the capacity of Sym004 to augment radiation response in lung cancer and head and neck cancer model systems. We first examined the antiproliferative effect of Sym004 and confirmed 40% to 60% growth inhibition by Sym004. Using clonogenic survival analysis, we identified that Sym004 potently increased cell kill by up to 10-fold following radiation exposure. A significant increase of γH2AX foci resulting from DNA double-strand breaks was observed in Sym004-treated cells following exposure to radiation. Mechanistic studies further showed that Sym004 enhanced radiation response via induction of cell-cycle arrest followed by induction of apoptosis and cell death, reflecting inhibitory effects on DNA damage repair. The expression of several critical molecules involved in radiation-induced DNA damage repair was significantly inhibited by Sym004, including DNAPK, NBS1, RAD50, and BRCA1. Using single and fractionated radiation in human tumor xenograft models, we confirmed that the combination of Sym004 and radiation resulted in significant tumor regrowth delay and superior antitumor effects compared with treatment with Sym004 or radiation alone. Taken together, these data reveal the strong capacity of Sym004 to augment radiation response in lung and head and neck cancers. The unique action mechanism of Sym004 warrants further investigation as a promising EGFR targeting agent combined with radiotherapy in cancer therapy. Mol Cancer Ther; 12(12); 2772–81. ©2013 AACR.
Data from Molecular Radiotherapy Using Cleavable Radioimmunoconjugates That Target EGFR and γH2AX
Authors: Cornelissen Bart , Waller Andrew , Able Sarah , Vallis Katherine A.
Published: March 2024

Abstract
Many anticancer therapies, including ionizing radiation (IR), cause cytotoxicity through generation of DNA double-strand breaks (DSB). Delivery of therapeutic radionuclides to DNA DSB sites can amplify this DNA damage, for additional therapeutic gain. Herein, we report on two radiopharmaceuticals, radiolabeled with the Auger electron emitter 111In, with dual specificity for both the intranuclear, DNA damage repair signaling protein γH2AX and the EGF receptor (EGFR). The EGFR ligand EGF was conjugated to a fluorophore- or 111In-labeled anti-γH2AX antibody, linked via a nuclear localization sequence (NLS) to ensure nuclear translocation. EGF conjugation was achieved either through a noncleavable PEG linker (PEO6) or a cleavable disulfide bond. Both conjugates selectively bound EGFR on fixed cells and γH2AX in cell extracts. Both compounds enter EGFR-expressing cells in an EGF/EGFR-dependent manner. However, only the cleavable compound was seen to associate with γH2AX foci in the nuclei of irradiated cells. Intracellular retention of the cleavable compound was prolonged in γH2AX-expressing cells. Clonogenic survival was significantly reduced when cells were exposed to IR (to induce γH2AX) plus 111In-labeled cleavable compound compared to either alone and compared to nonspecific controls. In vivo, uptake of 111In-labeled cleavable compound in MDA-MB-468 xenografts in athymic mice was 2.57 ± 0.47 percent injected dose/g (%ID/g) but increased significantly to 6.30 ± 1.47%ID/g in xenografts where γH2AX was induced by IR (P < 0.01). This uptake was dependent on EGF/EGFR and anti-γH2AX/γH2AX interactions. We conclude that tumor-specific delivery of radiolabeled antibodies directed against intranuclear epitopes is possible using cleavable antibody–peptide conjugates. Mol Cancer Ther; 12(11); 2472–82. ©2013 AACR.
Data from Transient Exposure to Quizartinib Mediates Sustained Inhibition of FLT3 Signaling while Specifically Inducing Apoptosis in FLT3-Activated Leukemia Cells
Authors: Gunawardane Ruwanthi N. , Nepomuceno Ronald R. , Rooks Allison M. , Hunt Jeremy P. , Ricono Jill M. , Belli Barbara , Armstrong Robert C.
Published: March 2024

Abstract
Fms-like tyrosine kinase 3 (FLT3) is implicated in the pathogenesis of acute myeloid leukemia (AML). FLT3-activating internal tandem duplication (ITD) mutations are found in approximately 30% of patients with AML and are associated with poor outcome in this patient population. Quizartinib (AC220) has previously been shown to be a potent and selective FLT3 inhibitor. In the current study, we expand on previous observations by showing that quizartinib potently inhibits the phosphorylation of FLT3 and downstream signaling molecules independent of FLT3 genotype, yet induces loss of viability only in cells expressing constitutively activated FLT3. We further show that transient exposure to quizartinib, whether in vitro or in vivo, leads to prolonged inhibition of FLT3 signaling, induction of apoptosis, and drastic reductions in tumor volume and pharmacodynamic endpoints. In vitro experiments suggest that these prolonged effects are mediated by slow binding kinetics that provide for durable inhibition of the kinase following drug removal/clearance. Together these data suggest quizartinib, with its unique combination of selectivity and potent/sustained inhibition of FLT3, may provide a safe and effective treatment against FLT3-driven leukemia. Mol Cancer Ther; 12(4); 438–47. ©2013 AACR.
Data from The CXCR2 Antagonist, SCH-527123, Shows Antitumor Activity and Sensitizes Cells to Oxaliplatin in Preclinical Colon Cancer Models
Authors: Ning Yan , Labonte Melissa J. , Zhang Wu , Bohanes Pierre O. , Gerger Armin , Yang Dongyun , Benhaim Leonor , Paez David , Rosenberg David O. , Nagulapalli Venkata Kalyan C. , Louie Stan G. , Petasis Nicos A. , Ladner Robert D. , Lenz Heinz-Josef
Published: March 2024

Abstract
Colorectal cancer is the second most common cause of cancer-related death in the United States. Recent studies showed that interleukin-8 (IL-8) and its receptors (CXCR1 and CXCR2) are significantly upregulated in both the tumor and its microenvironment, and act as key regulators of proliferation, angiogenesis, and metastasis. Our previous study showed that IL-8 overexpression in colorectal cancer cells triggers the upregulation of the CXCR2-mediated proliferative pathway. The aim of this study was to investigate whether the CXCR2 antagonist, SCH-527123, inhibits colorectal cancer proliferation and if it can sensitize colorectal cancer cells to oxaliplatin both in vitro and in vivo. SCH-527123 showed concentration-dependent antiproliferative effects in HCT116, Caco2, and their respective IL-8–overexpressing variants colorectal cancer cell lines. Moreover, SCH-527123 was able to suppress CXCR2-mediated signal transduction as shown through decreased phosphorylation of the NF-κB/mitogen-activated protein kinase (MAPK)/AKT pathway. These findings corresponded with decreased cell migration and invasion, while increased apoptosis in colorectal cancer cell lines. In vivo results verified that SCH-527123 treatment decreased tumor growth and microvessel density when compared with vehicle-treated tumors. Importantly, these preclinical studies showed that the combination of SCH-527123 and oxaliplatin resulted in a greater decrease in cell proliferation, tumor growth, apoptosis, and angiogenesis that was superior to single-agent treatment. Taken together, these findings suggest that targeting CXCR2 may block tumor proliferation, migration, invasion, and angiogenesis. In addition, CXCR2 blockade may further sensitize colorectal cancer to oxaliplatin treatment. Mol Cancer Ther; 11(6); 1353–64. ©2012 AACR.
Data from HDAC Inhibitor Entinostat Restores Responsiveness of Letrozole-Resistant MCF-7Ca Xenografts to Aromatase Inhibitors through Modulation of Her-2
Authors: Sabnis Gauri J. , Goloubeva Olga G. , Kazi Armina A. , Shah Preeti , Brodie Angela H.
Published: March 2024

Abstract
We previously showed that in innately resistant tumors, silencing of the estrogen receptor (ER) could be reversed by treatment with a histone deacetylase (HDAC) inhibitor, entinostat. Tumors were then responsive to aromatase inhibitor (AI) letrozole. Here, we investigated whether ER in the acquired letrozole-resistant tumors could be restored with entinostat. Ovariectomized athymic mice were inoculated with MCF-7Ca cells, supplemented with androstenedione (Δ4A), the aromatizable substrate. When the tumors reached about 300 mm3, the mice were treated with letrozole. After initial response to letrozole, the tumors eventually became resistant (doubled their initial volume). The mice then were grouped to receive letrozole, exemestane (250 μg/d), entinostat (50 μg/d), or the combination of entinostat with letrozole or exemestane for 26 weeks. The growth rates of tumors of mice treated with the combination of entinostat with letrozole or exemestane were significantly slower than with the single agent (P < 0.05). Analysis of the letrozole-resistant tumors showed entinostat increased ERα expression and aromatase activity but downregulated Her-2, p-Her-2, p-MAPK, and p-Akt. However, the mechanism of action of entinostat in reversing acquired resistance did not involve epigenetic silencing but rather included posttranslational as well as transcriptional modulation of Her-2. Entinostat treatment reduced the association of the Her-2 protein with HSP-90, possibly by reducing the stability of Her-2 protein. In addition, entinostat also reduced Her-2 mRNA levels and its stability. Our results suggest that the HDAC inhibitor may reverse letrozole resistance in cells and tumors by modulating Her-2 expression and activity. Mol Cancer Ther; 12(12); 2804–16. ©2013 AACR.
Data from A Polymeric Nanoparticle Encapsulated Small-Molecule Inhibitor of Hedgehog Signaling (NanoHHI) Bypasses Secondary Mutational Resistance to Smoothened Antagonists
Authors: Chenna Venugopal , Hu Chaoxin , Pramanik Dipankar , Aftab Blake T. , Karikari Collins , Campbell Nathaniel R. , Hong Seung-Mo , Zhao Ming , Rudek Michelle A. , Khan Saeed R. , Rudin Charles M. , Maitra Anirban
Published: March 2024

Abstract
Aberrant activation of the hedgehog (Hh) signaling pathway is one of the most prevalent abnormalities in human cancer. Tumors with cell autonomous Hh activation (e.g., medulloblastomas) can acquire secondary mutations at the Smoothened (Smo) antagonist binding pocket, which render them refractory to conventional Hh inhibitors. A class of Hh pathway inhibitors (HPI) has been identified that block signaling downstream of Smo; one of these compounds, HPI-1, is a potent antagonist of the Hh transcription factor Gli1 and functions independent of upstream components in the pathway. Systemic administration of HPI-1 is challenging due to its minimal aqueous solubility and poor bioavailability. We engineered a polymeric nanoparticle from [poly(lactic-co-glycolic acid); (PLGA)] conjugated with polyethylene glycol (PEG), encapsulating HPI-1 (NanoHHI). NanoHHI particles have an average diameter of approximately 60 nm, forms uniform aqueous suspension, and improved systemic bioavailability compared with the parent compound. In contrast to the prototype targeted Smo antagonist, HhAntag (Genentech), NanoHHI markedly inhibits the growth of allografts derived from Ptch−/+; Trp53−/− mouse medulloblastomas that harbor a SmoD477G binding site mutation (P < 0.001), which is accompanied by significant downregulation of mGli1 as well as bona fide Hh target genes (Akna, Cltb, and Olig2). Notably, NanoHHI combined with gemcitabine also significantly impedes the growth of orthotopic Pa03C pancreatic cancer xenografts that have a ligand-dependent, paracrine mechanism of Hh activation when compared with gemcitabine alone. No demonstrable hematologic or biochemical abnormalities were observed with NanoHHI administration. NanoHHI should be amenable to clinical translation in settings where tumors acquire mutational resistance to current Smo antagonists. Mol Cancer Ther; 11(1); 165–73. ©2011 AACR.