bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from DLK1 as a Potential Target against Cancer Stem/Progenitor Cells of Hepatocellular Carcinoma
Authors: Xu Xiao , Liu Rui-Fang , Zhang Xin , Huang Li-Yu , Chen Fei , Fei Qian-Lan , Han Ze-Guang
Published: April 2023

Abstract
Delta-like 1 homolog (DLK1; Drosophila) is a hepatic stem/progenitor cell marker in fetal livers that plays a vital role in oncogenesis of hepatocellular carcinoma (HCC). The aim of this study is to investigate whether DLK1 could serve as a potential therapeutic target against cancer stem/progenitor cells of HCC. DLK1+ and DLK1− cells were sorted by fluorescence-activated cell sorting and magnetic-activated cell sorting, respectively, and then were evaluated by flow cytometry. The biological behaviors of these isolated cells and those with DLK1 knockdown were assessed by growth curve, colony formation assay, spheroid colony formation, chemoresistance, and in vivo tumorigenicity. Adenovirus-mediated RNA interference was used to knockdown the endogenous DLK1. We found that DLK1+ population was less than 10% in almost all 17 HCC cell lines examined. DLK1+ HCC cells showed stronger ability of chemoresistance, colony formation, spheroid colony formation, and in vivo tumorigenicity compared with DLK1− cells. The DLK1+ HCC cells could generate the progeny without DLK1 expression. Furthermore, DLK1 knockdown could suppress the ability of proliferation, colony formation, spheroid colony formation, and in vivo tumorigenicity of Hep3B and Huh-7 HCC cells. Our data suggested that DLK1+ HCC cells have characteristics similar to those of cancer stem/progenitor cells. RNA interference against DLK1 can suppress the malignant behaviors of HCC cells, possibly through directly disrupting cancer stem/progenitor cells, which suggested that DLK1 could be a potential therapeutic target against the HCC stem/progenitor cells. Mol Cancer Ther; 11(3); 629–38. ©2012 AACR.
Data from PIK3CA Mutations in Patients with Advanced Cancers Treated with PI3K/AKT/mTOR Axis Inhibitors
Authors: Janku Filip , Tsimberidou Apostolia M. , Garrido-Laguna Ignacio , Wang Xuemei , Luthra Rajyalakshmi , Hong David S. , Naing Aung , Falchook Gerald S. , Moroney John W. , Piha-Paul Sarina A. , Wheler Jennifer J. , Moulder Stacy L. , Fu Siqing , Kurzrock Razelle
Published: April 2023

Abstract
Preclinical data suggest that PIK3CA mutations predict response to PI3K/AKT/mTOR inhibitors. Concomitant KRAS or BRAF mutations may mediate resistance. Therefore, tumors from patients referred to the phase I program for targeted therapy starting in October 2008 were analyzed for PIK3CA mutations using PCR-based DNA sequencing of exons 9 and 20. Consecutive patients with diverse tumor types and PIK3CA mutation were treated whenever possible with agents targeting the PI3K/AKT/mTOR pathway. Overall, PIK3CA mutations were detected in 25 of 217 patients (11.5%; exon 9, n = 11; exon 20, n = 14). In tumor types with more than 10 patients tested, PIK3CA mutations were most frequent in endometrial (3 of 14, 21%), ovarian (5 of 30, 17%), colorectal (9 of 54, 17%), breast (2 of 14, 14%), cervical (2 of 15, 13%), and squamous cell cancer of the head and neck (1 of 11, 9%). Of the 25 patients with PIK3CA mutations, 17 (68%) were treated on a protocol that included a PI3K/AKT/mTOR pathway inhibitor, and 6 (35%) achieved a partial response. In contrast, only 15 of 241 patients (6%) without documented PIK3CA mutations treated on the same protocols responded (P = 0.001). Of the 17 patients with PIK3CA mutations, 6 (35%) had simultaneous KRAS or BRAF mutations (colorectal, n = 4; ovarian, n = 2). Colorectal cancer patients with PIK3CA and KRAS mutations did not respond to therapy, whereas both ovarian cancer patients with PIK3CA and KRAS or BRAF mutations did. In conclusion, PIK3CA mutations were detected in 11.5% of patients with diverse solid tumors. The response rate was significantly higher for patients with PIK3CA mutations treated with PI3K/AKT/mTOR pathway inhibitors than for those without documented mutations. Mol Cancer Ther; 10(3); 558–65. ©2011 AACR.
Data from p53R2 Inhibits the Proliferation of Human Cancer Cells in Association with Cell-Cycle Arrest
Authors: Zhang Keqiang , Wu Jun , Wu Xiwei , Wang Xiaochen , Wang Yan , Zhou Ning , Kuo Mei-ling , Liu Xiyong , Zhou Bingsen , Chang Lufen , Ann David , Yen Yun
Published: April 2023

Abstract
Deregulation of the expression of p53R2, a p53-inducible homologue of the R2 subunit of ribonucleotide reductase, has been found in various human cancer tissues; however, the roles p53R2 plays in cancer progression and malignancy remain controversial. In the present study, we examined changes in gene expression profiles associated with p53R2 in cancer cells, using the analysis of cDNA microarray. Gene set enrichment analysis identified that the gene set regulating cell-cycle progression was significantly enriched in p53R2-silencing human oropharyngeal carcinoma KB cells. Attenuation of p53R2 expression significantly reduced p21 expression and moderately increased cyclin D1 expression in both wild-type p53 cancer cells (KB and MCF-7) and mutant p53 cancer cells (PC3 and MDA-MB-231). Conversely, overexpression of p53R2-GFP resulted in an increase in the expression of p21 and decrease in the expression of cyclin D1, which correlated with reduced cell population in S-phase in vitro and suppressed growth in vivo. Furthermore, the MAP/ERK kinase inhibitor PD98059 partially abolished modulation of p21 and cyclin D1 expression by p53R2. Moreover, under the conditions of nonstress and adriamycin-induced genotoxic stress, attenuation of p53R2 in KB cells significantly increased phosphorylated H2AX, which indicates that attenuation of p53R2 may enhance DNA damage induced by adriamycin. Overall, our study shows that p53R2 may suppress cancer cell proliferation partially by upregulation of p21 and downregulation of cyclin D1; p53R2 plays critical roles not only in DNA damage repair but also in proliferation of cancer cells. Mol Cancer Ther; 10(2); 269–78. ©2011 AACR.
Data from In Vitro and In Vivo Responses of Advanced Prostate Tumors to PSMA ADC, an Auristatin-Conjugated Antibody to Prostate-Specific Membrane Antigen
Authors: Wang Xinning , Ma Dangshe , Olson William C. , Heston Warren D.W.
Published: April 2023

Abstract
Prostate-specific membrane antigen (PSMA) is a membrane protein that is overexpressed manifold in prostate cancer and provides an attractive target for therapy. PSMA ADC is an antibody-drug conjugate (ADC) that consists of a fully human anti-PSMA monoclonal antibody conjugated to monomethylauristatin E through a valine-citrulline linker. In this study, the antitumor activity of PSMA ADC was evaluated against a panel of prostate cancer cell lines in vitro and in a novel in vivo model of taxane-refractory human prostate cancer. In vitro cell killing was efficient for cells with abundant PSMA expression (>105 molecules/cell; IC50 ≤ 0.022 nmol/L) and 1,000-fold less efficient for cells with undetectable PSMA (IC50 > 30 nmol/L). Intermediate potency (IC50 = 0.80 nmol/L) was observed for cells with approximately 104 molecules of PSMA per cell, indicating a threshold PSMA level for selective cell killing. Similar in vitro activity was observed against androgen-dependent and -independent cells that had abundant PSMA expression. In vitro activity of PSMA ADC was also dependent on internalization and proper N-glycosylation/folding of PSMA. In contrast, less potent and nonselective cytotoxic activity was observed for a control ADC, free monomethylauristatin E, and other microtubule inhibitors. PSMA ADC showed high in vivo activity in treating xenograft tumors that had progressed following an initial course of docetaxel therapy, including tumors that were large (>700 mm3) before treatment with PSMA ADC. This study defines determinants of antitumor activity of a novel ADC. The findings here support the clinical evaluation of this agent in advanced prostate cancer. Mol Cancer Ther; 10(9); 1728–39. ©2011 AACR.
Data from Inactivation of Mirk/Dyrk1b Kinase Targets Quiescent Pancreatic Cancer Cells
Authors: Ewton Daina Z. , Hu Jing , Vilenchik Maria , Deng Xiaobing , Luk Kin-chun , Polonskaia Ann , Hoffman Ann F. , Zipf Karen , Boylan John F. , Friedman Eileen A.
Published: April 2023

Abstract
A major problem in the treatment of cancer arises from quiescent cancer cells that are relatively insensitive to most chemotherapeutic drugs and radiation. Such residual cancer cells can cause tumor regrowth or recurrence when they reenter the cell cycle. Earlier studies showed that levels of the serine/theronine kinase Mirk/dyrk1B are elevated up to 10-fold in quiescent G0 tumor cells. Mirk uses several mechanisms to block cell cycling, and Mirk increases expression of antioxidant genes that decrease reactive oxygen species (ROS) levels and increase quiescent cell viability. We now show that a novel small molecule Mirk kinase inhibitor blocked tumor cells from undergoing reversible arrest in a quiescent G0 state and enabled some cells to exit quiescence. The inhibitor increased cycling in Panc1, AsPc1, and SW620 cells that expressed Mirk, but not in HCT116 cells that did not. Mirk kinase inhibition elevated ROS levels and DNA damage detected by increased phosphorylation of the histone protein H2AX and by S-phase checkpoints. The Mirk kinase inhibitor increased cleavage of the apoptotic proteins PARP and caspase 3, and increased tumor cell kill several-fold by gemcitabine and cisplatin. A phenocopy of these effects occurred following Mirk depletion, showing drug specificity. In previous studies Mirk knockout or depletion had no detectable effect on normal tissue, suggesting that the Mirk kinase inhibitor could have a selective effect on cancer cells expressing elevated levels of Mirk kinase. Mol Cancer Ther; 10(11); 2104–14. ©2011 AACR.
Data from Dual Targeting of Tumor Angiogenesis and Chemotherapy by Endostatin–Cytosine Deaminase–Uracil Phosphoribosyltransferase
Authors: Chen Chun-Te , Yamaguchi Hirohito , Lee Hong-Jen , Du Yi , Lee Heng-Huan , Xia Weiya , Yu Wen-Hsuan , Hsu Jennifer L. , Yen Chia-Jui , Sun Hui-Lung , Wang Yan , Yeh Edward T.H. , Hortobagyi Gabriel N. , Hung Mien-Chie
Published: April 2023

Abstract
Several antiangiogenic drugs targeting VEGF/VEGF receptor (VEGFR) that were approved by the Food and Drug Administration for many cancer types, including colorectal and lung cancer, can effectively reduce tumor growth. However, targeting the VEGF signaling pathway will probably influence the normal function of endothelial cells in maintaining homeostasis and can cause unwanted adverse effects. Indeed, emerging experimental evidence suggests that VEGF-targeting therapy induced less tumor cell–specific cytotoxicity, allowing residual cells to become more resistant and eventually develop a more malignant phenotype. We report an antitumor therapeutic EndoCD fusion protein developed by linking endostatin (Endo) to cytosine deaminase and uracil phosphoribosyltransferase (CD). Specifically, Endo possesses tumor antiangiogenesis activity that targets tumor endothelial cells, followed by CD, which converts the nontoxic prodrug 5-fluorocytosine (5-FC) to the cytotoxic antitumor drug 5-fluorouracil (5-FU) in the local tumor area. Moreover, selective targeting of tumor sites allows an increasing local intratumoral concentration of 5-FU, thus providing high levels of cytotoxic activity. We showed that treatment with EndoCD plus 5-FC, compared with bevacizumab plus 5-FU treatment, significantly increased the 5-FU concentration around tumor sites and suppressed tumor growth and metastasis in human breast and colorectal orthotropic animal models. In addition, in contrast to treatment with bevacizumab/5-FU, EndoCD/5-FC did not induce cardiotoxicity leading to heart failure in mice after long-term treatment. Our results showed that, compared with currently used antiangiogenic drugs, EndoCD possesses potent anticancer activity with virtually no toxic effects and does not increase tumor invasion or metastasis. Together, these findings suggest that EndoCD/5-FC could become an alternative option for future antiangiogenesis therapy. Mol Cancer Ther; 10(8); 1327–36. ©2011 AACR.
Data from Synergistic Effects of Foretinib with HER-Targeted Agents in MET and HER1- or HER2-Coactivated Tumor Cells
Authors: Liu Li , Shi Hong , Liu Yuan , Anderson Amber , Peterson John , Greger James , Martin Anne-Marie , Gilmer Tona M.
Published: April 2023

Abstract
The HER and MET receptor tyrosine kinases (RTK) are coactivated in a subset of human tumors. This study characterizes MET and HER expression and signaling in a panel of human tumor cell lines and the differential susceptibility of these cell lines to single agents or combinations of foretinib, a multikinase MET inhibitor, with HER-targeted agents, erlotinib or lapatinib. Most MET-amplified tumor lines without HER1 or HER2 amplification are sensitive to foretinib, whereas MET-amplified lines with HER1 or HER2 amplification are more sensitive to the combination of foretinib with lapatinib or erlotinib. Interestingly, MET-overexpressing tumor cell lines with HER1 or HER2 amplification also exhibited reduced sensitivity to lapatinib or erlotinib in the presence of hepatocyte growth factor (HGF), indicating MET activation can decrease the effectiveness of HER1/2 inhibitors in some cell lines. Consistent with this observation, the effect of HGF on lapatinib or erlotinib sensitivity in these cells was reversed by foretinib, other MET inhibitors, or siRNA to MET. Western blot analyses showed that combining foretinib with erlotinib or lapatinib effectively decreased the phosphorylation of MET, HER1, HER2, HER3, AKT, and ERK in these cells. Furthermore, HER2-positive advanced or metastatic breast cancer patients treated with lapatinib who had higher tumor MET expression showed shorter progression-free survival (19.29 weeks in MET-high patients vs. 28.14 weeks in MET-low patients, P < 0.0225). These data suggest that combination therapy with foretinib and HER-targeted agents should be tested as a treatment option for HER1- or HER2-positive patients with MET-amplified or -overexpressing tumors. Mol Cancer Ther; 10(3); 518–30. ©2011 AACR.
Data from PKCδ Regulates Death Receptor 5 Expression Induced by PS-341 through ATF4–ATF3/CHOP Axis in Human Lung Cancer Cells
Authors: Xu Linyan , Su Ling , Liu Xiangguo
Published: April 2023

Abstract
PS-341 (bortezomib), a proteasome inhibitor, has been approved for the treatment of multiple myeloma. Our previous work has shown that PS-341 induces death receptor 5 (DR5)–dependent apoptosis and enhances the TNF-related apoptosis-inducing ligand–induced apoptosis in human non–small cell lung cancer cells. However, the definite mechanism remains undefined. In the present study, we reveal that PKCδ and RSK2 mediate PS-341–induced DR5 upregulation, involving coactivation of endoplasmic reticulum (ER) stress. We discovered that PS-341 activated ER stress through elevating the expression of BiP, p-eIF2α, IRE1α, ATF4, ATF3, and CCAAT/enhancer-binding protein homologous protein (CHOP). Further study showed that DR5 upregulation was dependent on ATF4, ATF3, and CHOP expression. Silencing either one of the ATF4, ATF3, and CHOP expression decreased DR5 upregulation and subsequent apoptosis. We determined that ATF4 regulated ATF3 and CHOP expression. Thereafter, ATF3 and CHOP formed a complex and regulated DR5 expression. In addition, we discovered that the phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 and RSK2 were elevated after PS-341 treatment and inhibition of their phosphorylation using MAP-ERK kinase 1/2 inhibitor decreased the DR5 level, indicating that ERK/RSK2 signaling is involved in DR5 upregulation. Furthermore, we detected the cleavage of PKCδ, and the blockage of PKCδ expression cut down DR5 upregulation and apoptosis. Importantly, knockdown of PKCδ expression decreased the induction of ER stress and the phosphorylation of ERK1/2 and RSK2, suggesting that PKCδ regulates DR5 expression through ERK/RSK2 signaling and ATF4–CHOP/ATF3 axis. Collectively, we show that PS-341 induces PKCδ-dependent DR5 expression through activation of ERK/RSK2 and ER stress signaling pathway. Mol Cancer Ther; 11(10); 2174–82. ©2012 AACR.
Data from Micelle-Encapsulated Thiostrepton as an Effective Nanomedicine for Inhibiting Tumor Growth and for Suppressing FOXM1 in Human Xenografts
Authors: Wang Ming , Gartel Andrei L.
Published: April 2023

Abstract
The thiazole antiobiotic, thiostrepton, has been found to induce cell death in cancer cells through proteasome inhibition. As a proteasome inhibitor, thiostrepton has also been shown to suppress the expression of FOXM1, the oncogenic forkhead transcription factor overexpressed in cancer cells. In this study, we explored the potential in vivo anticancer properties of thiostrepton, delivered through nanoparticle encapsulation to xenograft models of breast and liver cancer. We encapsulated thiostrepton into micelles assembled from amphiphilic lipid-PEG (polyethylene glycol) molecules, where thiostrepton is solubilized within the inner lipid compartment of the micelle. Upon assembly, hydrophobic thiostrepton molecules are solubilized into the lipid component of the micelle shell, formed through the self-assembly of amphipilic lipid-PEG molecules. Maximum accumulation of micelle-thiostrepton nanoparticles (100 nm in diameter, −16 mV in zeta potential) into tumors was found at 4 hours postadministration and was retained for at least 24 hours. Upon continuous treatment, we found that nanoparticle-encapsulated thiostrepton reduced tumor growth rates of MDA-MB-231 and HepG2 cancer xenografts. Furthermore, we show for the first time the in vivo suppression of the oncogenic FOXM1 after treatment with proteasome inhibitors. Immunoblotting and immunohistochemical staining also showed increased apoptosis in the treated tumors, as indicated by cleaved caspase-3 expression. Our data suggest that the thiazole antibiotic/proteasome inhibitor thiostrepton, when formulated into nanoparticles, may be highly suited as a nanomedicine for treating human cancer. Mol Cancer Ther; 10(12); 2287–97. ©2011 AACR.
Data from A YKL-40–Neutralizing Antibody Blocks Tumor Angiogenesis and Progression: A Potential Therapeutic Agent in Cancers
Authors: Faibish Michael , Francescone Ralph , Bentley Brooke , Yan Wei , Shao Rong
Published: April 2023

Abstract
Accumulating evidence has indicated that expression levels of YKL-40, a secreted glycoprotein, were elevated in multiple advanced human cancers. Recently, we have identified an angiogenic role of YKL-40 in cancer development. However, blockade of the function of YKL-40, which implicates therapeutic value, has not been explored yet. Our current study sought to establish a monoclonal anti–YKL-40 antibody as a neutralizing antibody for the purpose of blocking tumor angiogenesis and metastasis. A mouse monoclonal anti–YKL-40 antibody (mAY) exhibited specific binding with recombinant YKL-40 and with YKL-40 secreted from osteoblastoma cells MG-63 and brain tumor cells U87. In the functional analysis, we found that mAY inhibited tube formation of microvascular endothelial cells in Matrigel induced by conditioned medium of MG-63 and U87 cells, as well as recombinant YKL-40. mAY also abolished YKL-40–induced activation of the membrane receptor VEGF receptor 2 (Flk-1/KDR) and intracellular signaling mitogen-activated protein (MAP) kinase extracellular signal–regulated kinase (Erk) 1 and Erk 2. In addition, mAY enhanced cell death response of U87 line to γ-irradiation through decreased expression of pAKT and AKT and accordingly, abrogated angiogenesis induced by the conditioned medium of U87 cells in which YKL-40 levels were elevated by treatment with γ-irradiation. Furthermore, treatment of xenografted tumor mice with mAY restrained tumor growth, angiogenesis, and progression. Taken together, this study has shown the therapeutic use for the mAY in treatment of tumor angiogenesis and metastasis. Mol Cancer Ther; 10(5); 742–51. ©2011 AACR.
Data from A Simplified Synthesis of Novel Dictyostatin Analogues with In Vitro Activity against Epothilone B–Resistant Cells and Antiangiogenic Activity in Zebrafish Embryos
Authors: Vollmer Laura L. , Jiménez Maria , Camarco Daniel P. , Zhu Wei , Daghestani Hikmat N. , Balachandran Raghavan , Reese Celeste E. , Lazo John S. , Hukriede Neil A. , Curran Dennis P. , Day Billy W. , Vogt Andreas
Published: April 2023

Abstract
The natural product (−)-dictyostatin is a microtubule-stabilizing agent that potently inhibits the growth of human cancer cells, including paclitaxel-resistant clones. Extensive structure–activity relationship studies have revealed several regions of the molecule that can be altered without loss of activity. The most potent synthetic dictyostatin analogue described to date, 6-epi-dictyostatin, has superior in vivo antitumor activity against human breast cancer xenografts compared with paclitaxel. In spite of their encouraging activities in preclinical studies, the complex chemical structure of the dictyostatins presents a major obstacle for their development into novel antineoplastic therapies. We recently reported a streamlined synthesis of 16-desmethyl-25,26-dihydrodictyostatins and found several agents that, when compared with 6-epi-dictyostatin, retained nanomolar activity in cellular microtubule-bundling assays but had lost activity against paclitaxel-resistant cells with mutations in β-tubulin. Extending these studies, we applied the new, highly convergent synthesis to generate 25,26-dihydrodictyostatin and 6-epi-25,26-dihydrodictyostatin. Both compounds were potent microtubule-perturbing agents that induced mitotic arrest and microtubule assembly in vitro and in intact cells. In vitro radioligand binding studies showed that 25,26-dihydrodictyostatin and its C6-epimer were capable of displacing [3H]paclitaxel and [14C]epothilone B from microtubules with potencies comparable to (−)-dictyostatin and discodermolide. Both compounds inhibited the growth of paclitaxel- and epothilone B–resistant cell lines at low nanomolar concentrations, synergized with paclitaxel in MDA-MB-231 human breast cancer cells, and had antiangiogenic activity in transgenic zebrafish larvae. These data identify 25,26-dihydrodictyostatin and 6-epi-25,26-dihydrodictyostatin as candidates for scale-up synthesis and further preclinical development. Mol Cancer Ther; 10(6); 994–1006. ©2011 AACR.
Data from Breakdown of the FLT3-ITD/STAT5 Axis and Synergistic Apoptosis Induction by the Histone Deacetylase Inhibitor Panobinostat and FLT3-Specific Inhibitors
Authors: Pietschmann Kristin , Bolck Hella Anna , Buchwald Marc , Spielberg Steffi , Polzer Harald , Spiekermann Karsten , Bug Gesine , Heinzel Thorsten , Böhmer Frank-Dietmar , Krämer Oliver H.
Published: April 2023

Abstract
Activating mutations of the class III receptor tyrosine kinase FLT3 are the most frequent molecular aberration in acute myeloid leukemia (AML). Mutant FLT3 accelerates proliferation, suppresses apoptosis, and correlates with poor prognosis. Therefore, it is a promising therapeutic target. Here, we show that RNA interference against FLT3 with an internal tandem duplication (FLT3-ITD) potentiates the efficacy of the histone deacetylase inhibitor (HDACi) panobinostat (LBH589) against AML cells expressing FLT3-ITD. Similar to RNA interference, tyrosine kinase inhibitors (TKI; AC220/cpd.102/PKC412) in combination with LBH589 exhibit superior activity against AML cells. Median dose–effect analyses of drug-induced apoptosis rates of AML cells (MV4-11 and MOLM-13) revealed combination index (CI) values indicating strong synergism. AC220, the most potent and FLT3-specific TKI, shows highest synergism with LBH589 in the low nanomolar range. A 4-hour exposure to LBH589 + AC220 already generates more than 50% apoptosis after 24 hours. Different cell lines lacking FLT3-ITD as well as normal peripheral blood mononuclear cells are not significantly affected by LBH589 + TKI, showing the specificity of this treatment regimen. Immunoblot analyses show that LBH589 + TKI induce apoptosis via degradation of FLT3-ITD and its prosurvival target STAT5. Previously, we showed the LBH589-induced proteasomal degradation of FLT3-ITD. Here, we show that activated caspase-3 also contributes to the degradation of FLT3-ITD and that STAT5 is a direct target of this protease. Our data strongly emphasize HDACi/TKI drug combinations as promising modality for the treatment of FLT3-ITD–positive AMLs. Mol Cancer Ther; 11(11); 2373–83. ©2012 AACR.
Data from Targeting the Insulin Growth Factor and the Vascular Endothelial Growth Factor Pathways in Ovarian Cancer
Authors: Shao Minghai , Hollar Stacy , Chambliss Daphne , Schmitt Jordan , Emerson Robert , Chelladurai Bhadrani , Perkins Susan , Ivan Mircea , Matei Daniela
Published: April 2023

Abstract
Antiangiogenic therapy is emerging as a highly promising strategy for the treatment of ovarian cancer, but the clinical benefits are usually transitory. The purpose of this study was to identify and target alternative angiogenic pathways that are upregulated in ovarian xenografts during treatment with bevacizumab. For this, angiogenesis-focused gene expression arrays were used to measure gene expression levels in SKOV3 and A2780 serous ovarian xenografts treated with bevacizumab or control. Reverse transcription-PCR was used for results validation. The insulin growth factor 1 (IGF-1) was found upregulated in tumor and stromal cells in the two ovarian xenograft models treated with bevacizumab. Cixutumumab was used to block IGF-1 signaling in vivo. Dual anti-VEGF and IGF blockade with bevacizumab and cixutumumab resulted in increased inhibition of tumor growth. Immunohistochemistry measured multivessel density, Akt activation, and cell proliferation, whereas terminal deoxynucleotidyl transferase–mediated dUTP nick end labeling (TUNEL) assay measured apoptosis in ovarian cancer xenografts. Bevacizumab and cixutumumab combination increased tumor cell apoptosis in vivo compared with therapy targeting either individual pathway. The combination blocked angiogenesis and cell proliferation but not more significantly than each antibody alone. In summary, IGF-1 activation represents an important mechanism of adaptive escape during anti-VEGF therapy in ovarian cancer. This study provides the rationale for designing bevacizumab-based combination regimens to enhance antitumor activity. Mol Cancer Ther; 11(7); 1576–86. ©2012 AACR.
Data from Cooperation between c-Met and Focal Adhesion Kinase Family Members in Medulloblastoma and Implications for Therapy
Authors: Guessous Fadila , Yang Yanzhi , Johnson Elizabeth , Marcinkiewicz Lukasz , Smith Matthew , Zhang Ying , Kofman Alexander , Schiff David , Christensen James , Abounader Roger
Published: April 2023

Abstract
We previously showed the involvement of the tyrosine kinase receptor c-Met in medulloblastoma malignancy. The nonreceptor tyrosine kinases focal adhesion kinase (FAK) and Pyk2 are key players in the progression of different cancers. However, their role in medulloblastoma malignancy is not well understood. In this study, using a protein array approach, we found that c-Met induces FAK and Pyk2 phosphorylation in medulloblastoma cells. We therefore studied the interactions between c-Met and FAK/Pyk2 and their implications for medulloblastoma therapy. We found that c-Met activates FAK and Pyk2 in several medulloblastoma cell lines. We also found that FAK and Pyk2 mediate the malignant effects of c-Met on medulloblastoma cell proliferation, migration, and invasion. On the basis of these findings, we hypothesized that combined c-Met and FAK inhibitions would have additive effects on the inhibition of medulloblastoma malignancy. To test this hypothesis, we assessed the effects on medulloblastoma malignancy parameters of single or combined treatments of medulloblastoma cells with c-Met and FAK small-molecule kinase inhibitors. We found a significant increase in the inhibitory effect of both inhibitors on medulloblastoma cell migration and cell invasion as compared with single inhibitions (P < 0.05). In addition, oral gavage treatment with c-Met inhibitor of mice bearing medulloblastoma xenografts significantly reduced in vivo tumor growth. Therefore, combining c-Met inhibitors with FAK inhibitors constitutes a new potential strategy for medulloblastoma therapy. Altogether, our study describes a role for FAK and Pyk2 in medulloblastoma malignancy, uncovers new interactions between c-Met and FAK/Pyk2, and proposes for the first time combining anti-c-Met and anti-FAK inhibitors as a new strategy for medulloblastoma therapy. Mol Cancer Ther; 11(2); 288–97. ©2011 AACR.
Data from YM-155 Potentiates the Effect of ABT-737 in Malignant Human Glioma Cells via Survivin and Mcl-1 Downregulation in an EGFR-Dependent Context
Authors: Jane Esther P. , Premkumar Daniel R. , DiDomenico Joseph D. , Hu Bo , Cheng Shi-Yuan , Pollack Ian F.
Published: April 2023

Abstract
Antiapoptotic proteins are commonly overexpressed in gliomas, contributing to therapeutic resistance. We recently reported that clinically achievable concentrations of the Bcl-2/Bcl-xL inhibitor ABT-737 failed to induce apoptosis in glioma cells, with persistent expression of survivin and Mcl-1. To address the role of these mediators in glioma apoptosis resistance, we analyzed the effects of YM-155, a survivin suppressant, on survival on a panel of glioma cell lines. YM-155 inhibited cell growth and downregulated survivin and Mcl-1 in a dose- and cell line–dependent manner. While U373, LN18, LNZ428, T98G, LN229, and LNZ308 cells exhibited an IC50 of 10 to 75 nmol/L, A172 cells were resistant (IC50 ∼ 250 nmol/L). No correlation was found between sensitivity to YM-155 and baseline expression of survivin or cIAP-1/cIAP-2/XIAP. However, strong correlation was observed between EGF receptor (EGFR) activation levels and YM-155 response, which was confirmed using EGFR-transduced versus wild-type cells. Because we postulated that decreasing Mcl-1 expression may enhance glioma sensitivity to ABT-737, we examined whether cotreatment with YM-155 promoted ABT-737 efficacy. YM-155 synergistically enhanced ABT-737–induced cytotoxicity and caspase-dependent apoptosis. Downregulation of Mcl-1 using short hairpin RNA also enhanced ABT-737–inducing killing, confirming an important role for Mcl-1 in mediating synergism between ABT-737 and YM-155. As with YM-155 alone, sensitivity to YM-155 and ABT-737 inversely correlated with EGFR activation status. However, sensitivity could be restored in highly resistant U87-EGFRvIII cells by inhibition of EGFR or its downstream pathways, highlighting the impact of EGFR signaling on Mcl-1 expression and the relevance of combined targeted therapies to overcome the multiple resistance mechanisms of these aggressive tumors. Mol Cancer Ther; 12(3); 326–38. ©2013 AACR.
Data from Berbamine Inhibits the Growth of Liver Cancer Cells and Cancer-Initiating Cells by Targeting Ca2+/Calmodulin-Dependent Protein Kinase II
Authors: Meng Zhipeng , Li Tao , Ma Xiaoxiao , Wang Xiaoqiong , Van Ness Carl , Gan Yichao , Zhou Hong , Tang Jinfen , Lou Guiyu , Wang Yafan , Wu Jun , Yen Yun , Xu Rongzhen , Huang Wendong
Published: April 2023

Abstract
Liver cancer is the third leading cause of cancer deaths worldwide but no effective treatment toward liver cancer is available so far. Therefore, there is an unmet medical need to identify novel therapies to efficiently treat liver cancer and improve the prognosis of this disease. Here, we report that berbamine and one of its derivatives, bbd24, potently suppressed liver cancer cell proliferation and induced cancer cell death by targeting Ca2+/calmodulin-dependent protein kinase II (CAMKII). Furthermore, berbamine inhibited the in vivo tumorigenicity of liver cancer cells in NOD/SCID mice and downregulated the self-renewal abilities of liver cancer–initiating cells. Chemical inhibition or short hairpin RNA–mediated knockdown of CAMKII recapitulated the effects of berbamine, whereas overexpression of CAMKII promoted cancer cell proliferation and increased the resistance of liver cancer cells to berbamine treatments. Western blot analyses of human liver cancer specimens showed that CAMKII was hyperphosphorylated in liver tumors compared with the paired peritumor tissues, which supports a role of CAMKII in promoting human liver cancer progression and the potential clinical use of berbamine for liver cancer therapies. Our data suggest that berbamine and its derivatives are promising agents to suppress liver cancer growth by targeting CAMKII. Mol Cancer Ther; 12(10); 2067–77. ©2013 AACR.
Data from MLN0905, a Small-Molecule PLK1 Inhibitor, Induces Antitumor Responses in Human Models of Diffuse Large B-cell Lymphoma
Authors: Shi Judy Quiju , Lasky Kerri , Shinde Vaishali , Stringer Bradley , Qian Mark G. , Liao Debra , Liu Ray , Driscoll Denise , Nestor Michelle Tighe , Amidon Benjamin S. , Rao Youlan , Duffey Matt O. , Manfredi Mark G. , Vos Tricia J. , Amore Natalie D' , Hyer Marc L.
Published: April 2023

Abstract
Diffuse large B-cell lymphoma (DLBCL) is the most common of the non–Hodgkin lymphomas, accounting for up to 30% of all newly diagnosed lymphoma cases. Current treatment options for this disease are effective, but not always curative; therefore, experimental therapies continue to be investigated. We have discovered an experimental, potent, and selective small-molecule inhibitor of PLK1, MLN0905, which inhibits cell proliferation in a broad range of human tumor cells including DLBCL cell lines. In our report, we explored the pharmacokinetic, pharmacodynamic, and antitumor properties of MLN0905 in DLBCL xenograft models grown in mice. These studies indicate that MLN0905 modulates the pharmacodynamic biomarker phosphorylated histone H3 (pHisH3) in tumor tissue. The antitumor activity of MLN0905 was evaluated in three human subcutaneous DLBCL xenograft models, OCI LY-10, OCI LY-19, and PHTX-22L (primary lymphoma). In each model, MLN0905 yielded significant antitumor activity on both a continuous (daily) and intermittent dosing schedule, underscoring dosing flexibility. The antitumor activity of MLN0905 was also evaluated in a disseminated xenograft (OCI LY-19) model to better mimic human DLBCL disease. In the disseminated model, MLN0905 induced a highly significant survival advantage. Finally, MLN0905 was combined with a standard-of-care agent, rituximab, in the disseminated OCI LY-19 xenograft model. Combining rituximab and MLN0905 provided both a synergistic antitumor effect and a synergistic survival advantage. Our findings indicate that PLK1 inhibition leads to pharmacodynamic pHisH3 modulation and significant antitumor activity in multiple DLBCL models. These data strongly suggest evaluating PLK1 inhibitors as DLBCL anticancer agents in the clinic. Mol Cancer Ther; 11(9); 2045–53. ©2012 AACR.
Data from Targeting FoxM1 Effectively Retards p53-Null Lymphoma and Sarcoma
Authors: Wang Zebin , Zheng Yu , Park Hyun Jung , Li Jing , Carr Janai R. , Chen Yi-ju , Kiefer Megan M. , Kopanja Dragana , Bagchi Srilata , Tyner Angela L. , Raychaudhuri Pradip
Published: April 2023

Abstract
The forkhead box transcription factor FOXM1 is considered to be a promising target for cancer therapy. However, the significance of FOXM1 in tumors harboring mutation in p53, which is very common, is unclear. In this study, we investigated the efficacy of FoxM1 targeting in spontaneous p53-null tumors using genetic ablation as well as using a peptide inhibitor of FOXM1. We show that conditional deletion of FoxM1 inhibits growth of the p53-null thymic lymphoma and sarcoma cells. In addition, deletion of FoxM1 induces apoptotic cell death of the p53-null tumors, accompanied by reduced expression of the FOXM1 target genes survivin and Bmi1. An ARF-derived peptide that inhibits the activity of FOXM1, by targeting it to the nucleolus, also induces apoptosis in the p53-null sarcoma and lymphoma, leading to a strong inhibition of their metastatic colonization. Together, our observations suggest that FOXM1 is critical for survival and growth of the p53-null lymphoma and sarcoma and provide proof-of-principle that FOXM1 is an effective therapeutic target for sarcoma and lymphoma carrying loss of function mutation in p53. Mol Cancer Ther; 12(5); 759–67. ©2013 AACR.
Data from Protein Kinase C Inhibitor AEB071 Targets Ocular Melanoma Harboring GNAQ Mutations via Effects on the PKC/Erk1/2 and PKC/NF-κB Pathways
Authors: Wu Xinqi , Li Jingjing , Zhu Meijun , Fletcher Jonathan A. , Hodi F. Stephen
Published: April 2023

Abstract
Somatic GNAQ mutations at codon 209 have been identified in approximately 50% of uveal melanomas and have been reported to be oncogenic through activating PLCβ/PKC/Erk1/2 pathways. We hypothesized that protein kinase C (PKC) may provide new opportunities for therapeutic targeting of uveal melanoma carrying GNAQ mutations. To test this hypothesis, uveal melanoma cells harboring wild-type or mutant GNAQ were treated with the PKC inhibitor AEB071 (sotrastaurin) or infected with lentivirus-expressing short hairpin RNAs (shRNA) targeting PKC isoforms. Notably, AEB071 at low micromolar concentrations significantly inhibited the growth of uveal melanoma cells harboring GNAQ mutations through induction of G1 arrest and apoptosis. However, AEB071 had little effect on uveal melanoma cells carrying wild-type GNAQ. AEB071-mediated cell inhibition in the GNAQ-mutated uveal melanoma was accompanied by inhibition of extracellular signal–regulated kinase (Erk)1/2 phosphorylation, NF-κB, decreased expression of cyclin D1, survivin, Bcl-xL, and XIAP, and increased expression of cyclin-dependent kinase inhibitor p27Kip1. AEB071 suppressed the expression of PKC α, β, δ, ϵ, and θ in GNAQ-mutated uveal melanoma cells. Our findings from shRNA-mediated knockdown studies revealed that these PKC isoforms are functionally important for uveal melanoma cells harboring GNAQ mutations. Furthermore, inhibitors of Erk1/2 and NF-κB pathways reduced viability of uveal melanoma cells. Together, our findings show that AEB071 exerts antitumor action on uveal melanoma cells carrying GNAQ mutations via targeting PKC/Erk1/2 and PKC/NF-κB pathways. Targeted PKC inhibition with drugs such as AEB071 offers novel therapeutic potential for uveal melanoma harboring GNAQ mutations. Mol Cancer Ther; 11(9); 1905–14. ©2012 AACR.
Data from Preclinical Pharmacology of AZD5363, an Inhibitor of AKT: Pharmacodynamics, Antitumor Activity, and Correlation of Monotherapy Activity with Genetic Background
Authors: Davies Barry R. , Greenwood Hannah , Dudley Phillippa , Crafter Claire , Yu De-Hua , Zhang Jingchuan , Li Jing , Gao Beirong , Ji Qunsheng , Maynard Juliana , Ricketts Sally-Ann , Cross Darren , Cosulich Sabina , Chresta Christine C. , Page Ken , Yates James , Lane Clare , Watson Rebecca , Luke Richard , Ogilvie Donald , Pass Martin
Published: April 2023

Abstract
AKT is a key node in the most frequently deregulated signaling network in human cancer. AZD5363, a novel pyrrolopyrimidine-derived compound, inhibited all AKT isoforms with a potency of 10 nmol/L or less and inhibited phosphorylation of AKT substrates in cells with a potency of approximately 0.3 to 0.8 μmol/L. AZD5363 monotherapy inhibited the proliferation of 41 of 182 solid and hematologic tumor cell lines with a potency of 3 μmol/L or less. Cell lines derived from breast cancers showed the highest frequency of sensitivity. There was a significant relationship between the presence of PIK3CA and/or PTEN mutations and sensitivity to AZD5363 and between RAS mutations and resistance. Oral dosing of AZD5363 to nude mice caused dose- and time-dependent reduction of PRAS40, GSK3β, and S6 phosphorylation in BT474c xenografts (PRAS40 phosphorylation EC50 ∼ 0.1 μmol/L total plasma exposure), reversible increases in blood glucose concentrations, and dose-dependent decreases in 2[18F]fluoro-2-deoxy-d-glucose (18F-FDG) uptake in U87-MG xenografts. Chronic oral dosing of AZD5363 caused dose-dependent growth inhibition of xenografts derived from various tumor types, including HER2+ breast cancer models that are resistant to trastuzumab. AZD5363 also significantly enhanced the antitumor activity of docetaxel, lapatinib, and trastuzumab in breast cancer xenografts. It is concluded that AZD5363 is a potent inhibitor of AKT with pharmacodynamic activity in vivo, has potential to treat a range of solid and hematologic tumors as monotherapy or a combinatorial agent, and has potential for personalized medicine based on the genetic status of PIK3CA, PTEN, and RAS. AZD5363 is currently in phase I clinical trials. Mol Cancer Ther; 11(4); 873–87. ©2012 AACR.
Data from Single-Chain Antibody-Based Immunotoxins Targeting Her2/neu: Design Optimization and Impact of Affinity on Antitumor Efficacy and Off-Target Toxicity
Authors: Cao Yu , Marks James D. , Huang Qian , Rudnick Stephen I. , Xiong Chiyi , Hittelman Walter N. , Wen Xiaoxia , Marks John W. , Cheung Lawrence H. , Boland Kim , Li Chun , Adams Gregory P. , Rosenblum Michael G.
Published: April 2023

Abstract
Recombinant immunotoxins, consisting of single-chain variable fragments (scFv) genetically fused to polypeptide toxins, represent potentially effective candidates for cancer therapeutics. We evaluated the affinity of various anti-Her2/neu scFv fused to recombinant gelonin (rGel) and its effect on antitumor efficacy and off-target toxicity. A series of rGel-based immunotoxins were created from the human anti-Her2/neu scFv C6.5 and various affinity mutants (designated ML3-9, MH3-B1, and B1D3) with affinities ranging from 10−8 to 10−11 mol/L. Against Her2/neu-overexpressing tumor cells, immunotoxins with increasing affinity displayed improved internalization and enhanced autophagic cytotoxicity. Targeting indices were highest for the highest affinity B1D3/rGel construct. However, the addition of free Her2/neu extracellular domain (ECD) significantly reduced the cytotoxicity of B1D3/rGel because of immune complex formation. In contrast, ECD addition had little impact on the lower affinity constructs in vitro. In vivo studies against established BT474 M1 xenografts showed growth suppression by all immunotoxins. Surprisingly, therapy with the B1D3-rGel induced significant liver toxicity because of immune complex formation with shed Her2/neu antigen in circulation. The MH3-B1/rGel construct with intermediate affinity showed effective tumor growth inhibition without inducing hepatotoxicity or complex formation. These findings show that while high-affinity constructs can be potent antitumor agents, they may also be associated with mistargeting through the facile formation of complexes with soluble antigen leading to significant off-target toxicity. Constructs composed of intermediate-affinity antibodies are also potent agents that are more resistant to immune complex formation. Therefore, affinity is an exceptionally important consideration when evaluating the design and efficacy of targeted therapeutics. Mol Cancer Ther; 11(1); 143–53. ©2011 AACR.
Data from Differential Induction of Apoptosis and Senescence by the DNA Methyltransferase Inhibitors 5-Azacytidine and 5-Aza-2′-Deoxycytidine in Solid Tumor Cells
Authors: Venturelli Sascha , Berger Alexander , Weiland Timo , Essmann Frank , Waibel Michaela , Nuebling Tina , Häcker Sabine , Schenk Martin , Schulze-Osthoff Klaus , Salih Helmut R. , Fulda Simone , Sipos Bence , Johnstone Ricky W. , Lauer Ulrich M. , Bitzer Michael
Published: April 2023

Abstract
Epigenetic alterations are a hallmark of cancer that govern the silencing of genes. Up to now, 5-azacytidine (5-aza-CR, Vidaza) and 5-aza-2′-deoxycytidine (5-aza-dC, Dacogen) are the only clinically approved DNA methyltransferase inhibitors (DNMTi). Current effort tries to exploit DNMTi application beyond acute leukemia or myelodysplastic syndrome, especially to solid tumors. Although both drugs only differ by a minimal structural difference, they trigger distinct molecular mechanisms that are highly relevant for a rational choice of new combination therapies. Therefore, we investigated cell death pathways in vitro in human hepatoma, colon, renal, and lung cancer cells and in vivo in chorioallantoic membrane and xenograft models. Real-time cancer cell monitoring and cytokine profiling revealed a profoundly distinct response pattern to both drugs. 5-aza-dC induced p53-dependent tumor cell senescence and a high number of DNA double-strand breaks. In contrast, 5-aza-CR downregulated p53, induced caspase activation and apoptosis. These individual response patterns of tumor cells could be verified in vivo in chorioallantoic membrane assays and in a hepatoma xenograft model. Although 5-aza-CR and 5-aza-dC are viewed as drugs with similar therapeutic activity, they induce a diverse molecular response in tumor cells. These findings together with other reported differences enable and facilitate a rational design of new combination strategies to further exploit the epigenetic mode of action of these two drugs in different areas of clinical oncology. Mol Cancer Ther; 12(10); 2226–36. ©2013 AACR.
Data from PRIMA-1Met/APR-246 Displays High Antitumor Activity in Multiple Myeloma By Induction of p73 and Noxa
Authors: Saha Manujendra N. , Jiang Hua , Yang Yijun , Reece Donna , Chang Hong
Published: April 2023

Abstract
Targeting p53 by the small-molecule PRIMA-1Met/APR-246 has shown promising preclinical activity in various cancer types. However, the mechanism of PRIMA-1Met–induced apoptosis is not completely understood and its effect on multiple myeloma cells is unknown. In this study, we evaluated antitumor effect of PRIMA-1Met alone or its combination with current antimyeloma agents in multiple myeloma cell lines, patient samples, and a mouse xenograft model. Results of our study showed that PRIMA-1Met decreased the viability of multiple myeloma cells irrespective of p53 status, with limited cytotoxicity toward normal hematopoietic cells. Treatment of multiple myeloma cells with PRIMA-1Met resulted in induction of apoptosis, inhibition of colony formation, and migration. PRIMA-1Met restored wild-type conformation of mutant p53 and induced activation of p73 upregulating Noxa and downregulating Mcl-1 without significant modulation of p53 level. siRNA-mediated silencing of p53 showed a little effect on apoptotic response of PRIMA-1Met, whereas knockdown of p73 led to substantial attenuation of apoptotic activity in multiple myeloma cells, indicating that PRIMA-1Met–induced apoptosis is, at least in part, p73–dependent. Importantly, PRIMA-1Met delayed tumor growth and prolonged survival of mice bearing multiple myeloma tumor. Furthermore, combined treatment of PRIMA-1Met with dexamethasone or doxorubicin displayed synergistic effects in both multiple myeloma cell lines and primary multiple myeloma samples. Consistent with our in vitro observations, cotreatment with PRIMA-1Met and dexamethasone resulted in enhanced antitumor activity in vivo. Our study for the first time shows antimyeloma activity of PRIMA-1Met and provides the rationale for its clinical evaluation in patients with multiple myeloma, including the high-risk group with p53 mutation/deletion. Mol Cancer Ther; 12(11); 2331–41. ©2013 AACR.