bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Characterization of the Mechanism of Action of the Pan Class I PI3K Inhibitor NVP-BKM120 across a Broad Range of Concentrations
Authors: Brachmann Saskia M. , Kleylein-Sohn Julia , Gaulis Swann , Kauffmann Audrey , Blommers Marcel J.J. , Kazic-Legueux Malika , Laborde Laurent , Hattenberger Marc , Stauffer Fabian , Vaxelaire Juliane , Romanet Vincent , Henry Chrystèle , Murakami Masato , Guthy Daniel Alexander , Sterker Dario , Bergling Sebastian , Wilson Christopher , Brümmendorf Thomas , Fritsch Christine , Garcia-Echeverria Carlos , Sellers William R. , Hofmann Francesco , Maira Sauveur-Michel
Published: April 2023

Abstract
The pan-phosphoinositide 3-kinase (PI3K) inhibitor BKM120 was found, at high concentrations, to cause cell death in various cellular systems, irrespective of their level of PI3K addiction. Transcriptional and biochemical profiling studies were used to identify the origin of these unexpected and apparently PI3K-independent effects. At 5- to 10-fold, the concentration needed to half-maximally inhibit PI3K signaling. BKM120 treatment caused changes in expression of mitotic genes and the induction of a robust G2–M arrest. Tubulin polymerization assays and nuclear magnetic resonance-binding studies revealed that BKM120 inhibited microtubule dynamics upon direct binding to tubulin. To assess the contribution of this off-target activity vis-à-vis the antitumor activity of BKM120 in PI3K-dependent tumors, we used a mechanistic PI3K-α–dependent model. We observed that, in vivo, daily treatment of mice with doses of BKM120 up to 40 mg/kg led to tumor regressions with no increase in the mitotic index. Thus, strong antitumor activity can be achieved in PI3K-dependent models at exposures that are below those necessary to engage the off-target activity. In comparison, the clinical data indicate that it is unlikely that BKM120 will achieve exposures sufficient to significantly engage the off-target activity at tolerated doses and schedules. However, in preclinical settings, the consequences of the off-target activity start to manifest themselves at concentrations above 1 μmol/L in vitro and doses above 50 mg/kg in efficacy studies using subcutaneous tumor–bearing mice. Hence, careful concentration and dose range selection is required to ensure that any observation can be correctly attributed to BKM120 inhibition of PI3K. Mol Cancer Ther; 11(8); 1747–57. ©2012 AACR.
Data from Dual Programmed Cell Death Pathways Induced by p53 Transactivation Overcome Resistance to Oncolytic Adenovirus in Human Osteosarcoma Cells
Authors: Hasei Joe , Sasaki Tsuyoshi , Tazawa Hiroshi , Osaki Shuhei , Yamakawa Yasuaki , Kunisada Toshiyuki , Yoshida Aki , Hashimoto Yuuri , Onishi Teppei , Uno Futoshi , Kagawa Shunsuke , Urata Yasuo , Ozaki Toshifumi , Fujiwara Toshiyoshi
Published: April 2023

Abstract
Tumor suppressor p53 is a multifunctional transcription factor that regulates diverse cell fates, including apoptosis and autophagy in tumor biology. p53 overexpression enhances the antitumor activity of oncolytic adenoviruses; however, the molecular mechanism of this occurrence remains unclear. We previously developed a tumor-specific replication-competent oncolytic adenovirus, OBP-301, that kills human osteosarcoma cells, but some human osteosarcoma cells were OBP-301–resistant. In this study, we investigated the antitumor activity of a p53-expressing oncolytic adenovirus, OBP-702, and the molecular mechanism of the p53-mediated cell death pathway in OBP-301–resistant human osteosarcoma cells. The cytopathic activity of OBP-702 was examined in OBP-301–sensitive (U2OS and HOS) and OBP-301–resistant (SaOS-2 and MNNG/HOS) human osteosarcoma cells. The molecular mechanism in the OBP-702–mediated induction of two cell death pathways, apoptosis and autophagy, was investigated in OBP-301–resistant osteosarcoma cells. The antitumor effect of OBP-702 was further assessed using an orthotopic OBP-301–resistant MNNG/HOS osteosarcoma xenograft tumor model. OBP-702 suppressed the viability of OBP-301–sensitive and -resistant osteosarcoma cells more efficiently than OBP-301 or a replication-deficient p53-expressing adenovirus (Ad-p53). OBP-702 induced more profound apoptosis and autophagy when compared with OBP-301 or Ad-p53. E1A-mediated miR-93/106b upregulation induced p21 suppression, leading to p53-mediated apoptosis and autophagy in OBP-702–infected cells. p53 overexpression enhanced adenovirus-mediated autophagy through activation of damage-regulated autophagy modulator (DRAM). Moreover, OBP-702 suppressed tumor growth in an orthotopic OBP-301–resistant MNNG/HOS xenograft tumor model. These results suggest that OBP-702–mediated p53 transactivation is a promising antitumor strategy to induce dual apoptotic and autophagic cell death pathways via regulation of miRNA and DRAM in human osteosarcoma cells. Mol Cancer Ther; 12(3); 314–25. ©2012 AACR.
Data from An Anti-Wnt5a Antibody Suppresses Metastasis of Gastric Cancer Cells In Vivo by Inhibiting Receptor-Mediated Endocytosis
Authors: Hanaki Hideaki , Yamamoto Hideki , Sakane Hiroshi , Matsumoto Shinji , Ohdan Hideki , Sato Akira , Kikuchi Akira
Published: April 2023

Abstract
Wnt5a is a representative ligand that activates the β-catenin–independent pathway in Wnt signaling. It was reported that the expression of Wnt5a in human gastric cancer is associated with aggressiveness and poor prognosis and that knockdown of Wnt5a reduces the ability of gastric cancer cells to metastasize in nude mice. Therefore, Wnt5a and its signaling pathway might be important targets for the therapy of gastric cancer. The aim of this study was to examine whether an anti-Wnt5a antibody affects metastasis of gastric cancer cells. One anti-Wnt5a polyclonal antibody (pAb5a-5) inhibited migration and invasion activities in vitro of gastric cancer cells with a high expression level of Wnt5a. Previously, it was shown that Wnt5a induces the internalization of receptors, which is required for Wnt5a-dependent activation of Rac1. pAb5a-5 inhibited Wnt5a-dependent internalization of receptors, thereby suppressed Wnt5a-dependent activation of Rac1. Laminin γ2 is one of target genes of Wnt5a signaling and Rac1 was involved in its expression. pAb5a-5 also inhibited Wnt5a-dependent expression of laminin γ2. In an experimental liver metastasis assay, gastric cancer cells were introduced into the spleens of nude mice. Laminin γ2 was required for liver metastatic ability of gastric cancer cells in vivo. Furthermore, intraperitoneal injection of pAb5a-5 inhibited the metastatic ability of gastric cancer cells. These results suggest that an anti-Wnt5a antibody was capable of suppressing Wnt5a-dependent internalization of receptors, resulting in the prevention of metastasis of gastric cancer cells by inhibiting the activation of Rac1 and the expression of laminin γ2. Mol Cancer Ther; 11(2); 298–307. ©2011 AACR.
Data from Antitumor Effect of SIRT1 Inhibition in Human HCC Tumor Models In Vitro and In Vivo
Authors: Portmann Simone , Fahrner René , Lechleiter Antje , Keogh Adrian , Overney Sarah , Laemmle Alexander , Mikami Kei , Montani Matteo , Tschan Mario P. , Candinas Daniel , Stroka Deborah
Published: April 2023

Abstract
Sirtuins (SIRT1-7) are a highly conserved family of NAD+-dependent enzymes that control the activity of histone and nonhistone regulatory proteins. SIRT1 is purposed to promote longevity and to suppress the initiation of some cancers. Nevertheless, SIRT1 is reported to function as a tumor suppressor as well as an oncogenic protein. Our data show that compared with normal liver or surrounding tumor tissue, SIRT1 is strongly overexpressed in human hepatocellular carcinoma (HCC). In addition, human HCC cell lines (Hep3B, HepG2, HuH7, HLE, HLF, HepKK1, skHep1) were screened for the expression of the sirtuin family members and only SIRT1 was consistently overexpressed compared with normal hepatocytes. To determine its effect on HCC growth, SIRT1 activity was inhibited either with lentiviruses expressing short hairpin RNAs or with the small molecule inhibitor, cambinol. Knockdown or inhibition of SIRT1 activity had a cytostatic effect, characterized by an altered morphology, impaired proliferation, an increased expression of differentiation markers, and cellular senescence. In an orthotopic xenograft model, knockdown of SIRT1 resulted in 50% fewer animals developing tumors and cambinol treatment resulted in an overall lower tumor burden. Taken together, our data show that inhibition of SIRT1 in HCC cells impairs their proliferation in vitro and tumor formation in vivo. These data suggest that SIRT1 expression positively influences the growth of HCC and support further studies aimed to block its activity alone or in combination as a novel treatment strategy. Mol Cancer Ther; 12(4); 499–508. ©2013 AACR.
Data from In Silico Screening Reveals Structurally Diverse, Nanomolar Inhibitors of NQO2 That Are Functionally Active in Cells and Can Modulate NF-κB Signaling
Authors: Nolan Karen A. , Dunstan Mark S. , Caraher Mary C. , Scott Katherine A. , Leys David , Stratford Ian J.
Published: April 2023

Abstract
The National Cancer Institute chemical database has been screened using in silico docking to identify novel nanomolar inhibitors of NRH:quinone oxidoreductase 2 (NQO2). The inhibitors identified from the screen exhibit a diverse range of scaffolds and the structure of one of the inhibitors, NSC13000 cocrystalized with NQO2, has been solved. This has been used to aid the generation of a structure–activity relationship between the computationally derived binding affinity and experimentally measured enzyme inhibitory potency. Many of the compounds are functionally active as inhibitors of NQO2 in cells at nontoxic concentrations. To show this, advantage was taken of the NQO2-mediated toxicity of the chemotherapeutic drug CB1954. The toxicity of this drug is substantially reduced when the function of NQO2 is inhibited, and many of the compounds achieve this in cells at nanomolar concentrations. The NQO2 inhibitors also attenuated TNFα-mediated, NF-кB–driven transcriptional activity. The link between NQO2 and the regulation of NF-кB was confirmed by using short interfering RNA to NQO2 and by the observation that NRH, the cofactor for NQO2 enzyme activity, could regulate NF-кB activity in an NQO2-dependent manner. NF-кB is a potential therapeutic target and this study reveals an underlying mechanism that may be usable for developing new anticancer drugs. Mol Cancer Ther; 11(1); 194–203. ©2011 AACR.
Data from Bortezomib and SAHA Synergistically Induce ROS-Driven Caspase-Dependent Apoptosis of Nasopharyngeal Carcinoma and Block Replication of Epstein–Barr Virus
Authors: Hui Kwai Fung , Lam Benjamin H.W. , Ho Dona N. , Tsao Sai Wah , Chiang Alan K.S.
Published: April 2023

Abstract
A novel drug combination of a proteasome inhibitor, bortezomib, and a histone deacetylase inhibitor, suberoylanilide hydroxamic acid (SAHA), was tested in nasopharyngeal carcinoma (NPC), both in vitro and in vivo. Dose-response of different concentrations of bortezomib and SAHA on inhibition of cell proliferation of NPC was determined. Mechanisms of apoptosis and effects on lytic cycle activation of Epstein–Barr virus (EBV) were investigated. Combination of bortezomib and SAHA (bortezomib/SAHA) synergistically induced killing of a panel of NPC cell lines. Pronounced increase in sub-G1, Annexin V–positive, and terminal deoxynucleotidyl transferase–mediated dUTP nick end labeling (TUNEL)–positive cell populations were detected after treatment with bortezomib/SAHA when compared with either drug alone. Concomitantly, markedly augmented proteolytic cleavage of PARP, caspase-3, -7, -8, and -9, reactive oxygen species (ROS) generation, and caspase-8–dependent histone acetylation were observed. ROS scavenger, N-acetyl cysteine, diminished the apoptotic effects of bortezomib/SAHA, whereas caspase inhibitor Z-VAD-FMK significantly suppressed the apoptosis without decreasing the generation of ROS. Bortezomib inhibited SAHA's induction of EBV replication and abrogated production of infectious viral particles in NPC cells. Furthermore, bortezomib/SAHA potently induced apoptosis and suppressed the growth of NPC xenografts in nude mice. In conclusion, the novel drug combination of bortezomib and SAHA is highly synergistic in the killing of NPC cells in vitro and in vivo. The major mechanism of cell death is ROS-driven caspase-dependent apoptosis. Bortezomib antagonizes SAHA's activation of EBV lytic cycle in NPC cells. This study provides a strong basis for clinical testing of the combination drug regimen in patients with NPC. Mol Cancer Ther; 12(5); 747–58. ©2013 AACR.
Data from Preclinical Activity of the Type II CD20 Antibody GA101 (Obinutuzumab) Compared with Rituximab and Ofatumumab In Vitro and in Xenograft Models
Authors: Herter Sylvia , Herting Frank , Mundigl Olaf , Waldhauer Inja , Weinzierl Tina , Fauti Tanja , Muth Gunter , Ziegler-Landesberger Doris , Van Puijenbroek Erwin , Lang Sabine , Duong Minh Ngoc , Reslan Lina , Gerdes Christian A. , Friess Thomas , Baer Ute , Burtscher Helmut , Weidner Michael , Dumontet Charles , Umana Pablo , Niederfellner Gerhard , Bacac Marina , Klein Christian
Published: April 2023

Abstract
We report the first preclinical in vitro and in vivo comparison of GA101 (obinutuzumab), a novel glycoengineered type II CD20 monoclonal antibody, with rituximab and ofatumumab, the two currently approved type I CD20 antibodies. The three antibodies were compared in assays measuring direct cell death (AnnexinV/PI staining and time-lapse microscopy), complement-dependent cytotoxicity (CDC), antibody-dependent cell-mediated cytotoxicity (ADCC), antibody-dependent cell-mediated phagocytosis (ADCP), and internalization. The models used for the comparison of their activity in vivo were SU-DHL4 and RL xenografts. GA101 was found to be superior to rituximab and ofatumumab in the induction of direct cell death (independent of mechanical manipulation required for cell aggregate disruption formed by antibody treatment), whereas it was 10 to 1,000 times less potent in mediating CDC. GA101 showed superior activity to rituximab and ofatumumab in ADCC and whole-blood B-cell depletion assays, and was comparable with these two in ADCP. GA101 also showed slower internalization rate upon binding to CD20 than rituximab and ofatumumab. In vivo, GA101 induced a strong antitumor effect, including complete tumor remission in the SU-DHL4 model and overall superior efficacy compared with both rituximab and ofatumumab. When rituximab-pretreated animals were used, second-line treatment with GA101 was still able to control tumor progression, whereas tumors escaped rituximab treatment. Taken together, the preclinical data show that the glyoengineered type II CD20 antibody GA101 is differentiated from the two approved type I CD20 antibodies rituximab and ofatumumab by its overall preclinical activity, further supporting its clinical investigation. Mol Cancer Ther; 12(10); 2031–42. ©2013 AACR.
Data from MTI-101 (Cyclized HYD1) Binds a CD44 Containing Complex and Induces Necrotic Cell Death in Multiple Myeloma
Authors: Gebhard Anthony W. , Jain Priyesh , Nair Rajesh R. , Emmons Michael F. , Argilagos Raul F. , Koomen John M. , McLaughlin Mark L. , Hazlehurst Lori A.
Published: April 2023

Abstract
Our laboratory recently reported that treatment with the d-amino acid containing peptide HYD1 induces necrotic cell death in multiple myeloma cell lines. Because of the intriguing biological activity and promising in vivo activity of HYD1, we pursued strategies for increasing the therapeutic efficacy of the linear peptide. These efforts led to a cyclized peptidomimetic, MTI-101, with increased in vitro activity and robust in vivo activity as a single agent using two myeloma models that consider the bone marrow microenvironment. MTI-101 treatment similar to HYD1 induced reactive oxygen species, depleted ATP levels, and failed to activate caspase-3. Moreover, MTI-101 is cross-resistant in H929 cells selected for acquired resistance to HYD1. Here, we pursued an unbiased chemical biology approach using biotinylated peptide affinity purification and liquid chromatography/tandem mass spectrometry analysis to identify binding partners of MTI-101. Using this approach, CD44 was identified as a predominant binding partner. Reducing the expression of CD44 was sufficient to induce cell death in multiple myeloma cell lines, indicating that multiple myeloma cells require CD44 expression for survival. Ectopic expression of CD44s correlated with increased binding of the FAM-conjugated peptide. However, ectopic expression of CD44s was not sufficient to increase the sensitivity to MTI-101–induced cell death. Mechanistically, we show that MTI-101–induced cell death occurs via a Rip1-, Rip3-, or Drp1-dependent and -independent pathway. Finally, we show that MTI-101 has robust activity as a single agent in the SCID-Hu bone implant and 5TGM1 in vivo model of multiple myeloma. Mol Cancer Ther; 12(11); 2446–58. ©2013 AACR.
Data from Novel Inhibitors of Rad6 Ubiquitin Conjugating Enzyme: Design, Synthesis, Identification, and Functional Characterization
Authors: Sanders Matthew A. , Brahemi Ghali , Nangia-Makker Pratima , Balan Vitaly , Morelli Matteo , Kothayer Hend , Westwell Andrew D. , Shekhar Malathy P.V.
Published: April 2023

Abstract
Protein ubiquitination is important for cell signaling, DNA repair, and proteasomal degradation, and it is not surprising that alterations in ubiquitination occur frequently in cancer. Ubiquitin-conjugating enzymes (E2) mediate ubiquitination by selective interactions with ubiquitin-activating (E1) and ubiquitin ligase (E3) enzymes, and thus selective E2 small molecule inhibitor (SMI) will provide specificity unattainable with proteasome inhibitors. Here we describe synthesis and functional characterization of the first SMIs of human E2 Rad6B, a fundamental component of translesion synthesis DNA repair. A pharmacophore model for consensus E2 ubiquitin-binding sites was generated for virtual screening to identify E2 inhibitor candidates. Twelve triazine (TZ) analogs screened in silico by molecular docking to the Rad6B X-ray structure were verified by their effect on Rad6B ubiquitination of histone H2A. TZs #8 and 9 docked to the Rad6B catalytic site with highest complementarity. TZs #1, 2, 8, and 9 inhibited Rad6B-ubiquitin thioester formation and subsequent ubiquitin transfer to histone H2A. SMI #9 inhibition of Rad6 was selective as BCA2 ubiquitination by E2 UbcH5 was unaffected by SMI #9. SMI #9 more potently inhibited proliferation, colony formation, and migration than SMI #8, and induced MDA-MB-231 breast cancer cell G2–M arrest and apoptosis. Ubiquitination assays using Rad6 immunoprecipitated from SMI #8- or 9-treated cells confirmed inhibition of endogenous Rad6 activity. Consistent with our previous data showing Rad6B-mediated polyubiquitination stabilizes β-catenin, MDA-MB-231 treatment with SMIs #8 or 9 decreased β-catenin protein levels. Together these results describe identification of the first Rad6 SMIs. Mol Cancer Ther; 12(4); 373–83. ©2013 AACR.
Data from Overcoming Erlotinib Resistance in EGFR Mutation–Positive Non–Small Cell Lung Cancer Cells by Targeting Survivin
Authors: Okamoto Kunio , Okamoto Isamu , Hatashita Erina , Kuwata Kiyoko , Yamaguchi Haruka , Kita Aya , Yamanaka Kentaro , Ono Mayumi , Nakagawa Kazuhiko
Published: April 2023

Abstract
Loss of PTEN was recently shown to contribute to resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) in EGFR mutation–positive non–small cell lung cancer (NSCLC) through activation of the protein kinase AKT. We previously showed that downregulation of the expression of the antiapoptotic protein survivin by EGFR–TKIs contributes to EGFR–TKI-induced apoptosis in EGFR mutation–positive NSCLC cells. We have now investigated the role of survivin expression in EGFR–TKI resistance induced by PTEN loss. The EGFR–TKI erlotinib did not affect survivin expression or induce apoptosis in EGFR mutation–positive NSCLC cells with PTEN loss. Downregulation of survivin either by transfection with a specific short interfering RNA or by exposure to the small-molecule survivin suppressor YM155 reversed erlotinib resistance in such cells in vitro. Furthermore, combination therapy with YM155 and erlotinib inhibited the growth of tumors formed by EGFR mutation–positive, PTEN-deficient NSCLC cells in nude mice to a greater extent than did treatment with either drug alone. These results thus indicate that persistent activation of signaling by the AKT–survivin pathway induced by PTEN loss underlies a mechanism of resistance to erlotinib-induced apoptosis in EGFR mutation–positive NSCLC. They further suggest that the targeting of survivin has the potential to overcome EGFR–TKI resistance in EGFR mutation–positive NSCLC. Mol Cancer Ther; 11(1); 204–13. ©2011 AACR.
Data from Sensitization of TRAIL-Induced Cell Death by 20(S)-Ginsenoside Rg3 via CHOP-Mediated DR5 Upregulation in Human Hepatocellular Carcinoma Cells
Authors: Lee Ju-Yeon , Jung Kyung Hee , Morgan Michael J. , Kang Yi-Rae , Lee Hee-Seung , Koo Gi-Bang , Hong Soon-Sun , Kwon Sung Won , Kim You-Sun
Published: April 2023

Abstract
The TRAIL pathway is a potential therapeutic target for anticancer drugs due to selective cytotoxicity in cancer cells. Despite considerable promise, TRAIL or TRAIL receptor agonists have been used thus far with limited success in multiple clinical trials, in part due to acquired TRAIL resistance during chemotherapeutic treatment. Hepatocellular carcinoma (HCC) is a common solid tumor and the third leading cause of cancer-related death worldwide. Classical chemotherapy is not effective for HCC treatment and targeted therapy is limited to sorafenib. Isolated from Panax ginseng CA Meyer, 20(S)-ginsenoside Rg3 is a steroidal saponin with high pharmacologic activity that has been shown to sensitize cells to some chemotherapeutic agents. We investigated the sensitizing effect of Rg3 on TRAIL-induced cell death in HCC cells. We show Rg3 is capable of promoting TRAIL-induced apoptosis in a number of HCC cell lines, including HepG2, SK-Hep1, Huh-7, and Hep3B, but not in normal HL-7702 hepatocytes, indicating that Rg3 sensitization to TRAIL may be specific to cancer cells. Mechanistically, we found that Rg3 upregulates DR5 expression at the transcriptional level. DR5 upregulation in this case is mediated by C/EBP homology protein (CHOP), an important endoplasmic reticulum stress responsive protein. Furthermore, Rg3 is well tolerated and enhances the therapeutic efficacy of TRAIL in mouse xenograft models, suggesting that chemosensitization also occurs in vivo. Taken together, our study identifies Rg3 as a novel anticancer therapeutic agent and supports the further development of Rg3 as a chemosensitizer in combined therapy with TRAIL. Mol Cancer Ther; 12(3); 274–85. ©2012 AACR.
Data from Breast Cancer–Derived Bone Metastasis Can Be Effectively Reduced through Specific c-MET Inhibitor Tivantinib (ARQ 197) and shRNA c-MET Knockdown
Authors: Previdi Sara , Abbadessa Giovanni , Dalò Francesca , France Dennis S. , Broggini Massimo
Published: April 2023

Abstract
Breast cancer exhibits a propensity to metastasize to bone, resulting in debilitating skeletal complications associated with significant morbidity and poor prognosis. The cross-talk between metastatic cancer cells and bone is critical to the development and progression of bone metastases. We have shown the involvement of the HGF/c-MET system in tumor–bone interaction contributing to human breast cancer metastasis. Therefore, disruption of HGF/c-MET signaling is a potential targeted approach to treating metastatic bone disease. In this study, we evaluated the effects of c-MET inhibition by both an oral, selective, small-molecule c-MET inhibitor, tivantinib, and a specific short hairpin RNA (shRNA) against c-MET in a mouse model of human breast cancer. Tivantinib exhibited dose-dependent antimetastatic activity in vivo, and the 120 mg/kg dose, proven to be suboptimal in reducing subcutaneous tumor growth, induced significant inhibition of metastatic growth of breast cancer cells in bone and a noteworthy reduction of tumor-induced osteolysis. shRNA-mediated c-MET silencing did not affect in vitro proliferation of bone metastatic cells, but significantly reduced their migration, and this effect was further enhanced by tivantinib. Both observations were confirmed in vivo. Indeed, more pronounced tumor growth suppression with concomitant marked decreases of lytic lesions and prolongation of survival were achieved by dual c-MET inhibition using both tivantinib and RNA interference strategies. Overall, our findings highlighted the effectiveness of c-MET inhibition in delaying the onset and progression of bone metastases and strongly suggest that targeting c-MET may have promising therapeutic value in the treatment of bone metastases from breast cancer. Mol Cancer Ther; 11(1); 214–23. ©2011 AACR.
Data from Evading Pgp Activity in Drug-Resistant Cancer Cells: A Structural and Functional Study of Antitubulin Furan Metotica Compounds
Authors: Nguyen Tam Luong , Cera Maria Rosaria , Pinto Andrea , Lo Presti Leonardo , Hamel Ernest , Conti Paola , Gussio Rick , De Wulf Peter
Published: April 2023

Abstract
Tumor resistance to antitubulin drugs resulting from P-glycoprotein (Pgp) drug-efflux activity, increased expression of the βIII tubulin isotype, and alterations in the drug-binding sites are major obstacles in cancer therapy. Consequently, novel antitubulin drugs that overcome these challenges are of substantial interest. Here, we study a novel chemotype named furan metotica that localizes to the colchicine-binding site in β-tubulin, inhibits tubulin polymerization, and is not antagonized by Pgp. To elucidate the structure–activity properties of this chiral chemotype, the enantiomers of its most potent member were separated and their absolute configurations determined by X-ray crystallography. Both isomers were active and inhibited all 60 primary cancer cell lines tested at the U.S. National Cancer Institute. They also efficiently killed drug-resistant cancer cells that overexpressed the Pgp drug-efflux pump 106-fold. In vitro, the R-isomer inhibited tubulin polymerization at least 4-fold more potently than the S-isomer, whereas in human cells the difference was 30-fold. Molecular modeling showed that the two isomers bind to β-tubulin in distinct manners: the R-isomer binds in a colchicine-like mode and the S-isomer in a podophyllotoxin-like fashion. In addition, the dynamic binding trajectory and occupancy state of the R-isomer were energetically more favorable then those of the S-isomer, explaining the observed differences in biologic activities. The ability of a racemic drug to assume the binding modes of two prototypical colchicine-site binders represents a novel mechanistic basis for antitubulin activity and paves the way toward a comprehensive design of novel anticancer agents. Mol Cancer Ther; 11(5); 1103–11. ©2012 AACR.
Data from The Checkpoint Kinase Inhibitor AZD7762 Potentiates Chemotherapy-Induced Apoptosis of p53-Mutated Multiple Myeloma Cells
Authors: Landau Heather J. , McNeely Samuel C. , Nair Jayasree S. , Comenzo Raymond L. , Asai Takashi , Friedman Hillel , Jhanwar Suresh C. , Nimer Stephen D. , Schwartz Gary K.
Published: April 2023

Abstract
DNA cross-linking agents are frequently used in the treatment of multiple myeloma–generating lesions, which activate checkpoint kinase 1 (Chk1), a critical transducer of the DNA damage response. Chk1 activation promotes cell survival by regulating cell-cycle arrest and DNA repair following genotoxic stress. The ability of AZD7762, an ATP-competitive Chk1/2 inhibitor to increase the efficacy of the DNA-damaging agents bendamustine, melphalan, and doxorubicin was examined using four human myeloma cell lines, KMS-12-BM, KMS-12-PE, RPMI-8226, and U266B1. The in vitro activity of AZD7762 as monotherapy and combined with alkylating agents and the “novel” drug bortezomib was evaluated by studying its effects on cytotoxicity, signaling, and apoptotic pathways. The Chk1/2 inhibitor AZD7762 potentiated the antiproliferative effects of bendamustine, melphalan, and doxorubicin but not bortezomib in multiple myeloma cell lines that were p53-deficient. Increased γH2AX staining in cells treated with bendamustine or melphalan plus AZD7762 indicates a greater degree of DNA damage with combined therapy. Abrogation of the G2–M checkpoint by AZD7762 resulted in mitotic catastrophe with ensuing apoptosis evidenced by PARP and caspase-3 cleavage. In summary, the cytotoxic effects of bendamustine, melphalan and doxorubicin on p53-deficient multiple myeloma cell lines were enhanced by the coadministration of AZD7762. These data provide a rationale for testing these combinations in patients with relapsed and/or refractory multiple myeloma. Mol Cancer Ther; 11(8); 1781–8. ©2012 AACR.
Data from Targeting KRAS-Mutant Non–Small Cell Lung Cancer with the Hsp90 Inhibitor Ganetespib
Authors: Acquaviva Jaime , Smith Donald L. , Sang Jim , Friedland Julie C. , He Suqin , Sequeira Manuel , Zhang Chaohua , Wada Yumiko , Proia David A.
Published: April 2023

Abstract
Mutant KRAS is a feature of more than 25% of non–small cell lung cancers (NSCLC) and represents one of the most prevalent oncogenic drivers in this disease. NSCLC tumors with oncogenic KRAS respond poorly to current therapies, necessitating the pursuit of new treatment strategies. Targeted inhibition of the molecular chaperone Hsp90 results in the coordinated blockade of multiple oncogenic signaling pathways in tumor cells and has thus emerged as an attractive avenue for therapeutic intervention in human malignancies. Here, we examined the activity of ganetespib, a small-molecule inhibitor of Hsp90 currently in clinical trials for NSCLCs in a panel of lung cancer cell lines harboring a diverse spectrum of KRAS mutations. In vitro, ganetespib was potently cytotoxic in all lines, with concomitant destabilization of KRAS signaling effectors. Combinations of low-dose ganetespib with MEK or PI3K/mTOR inhibitors resulted in superior cytotoxic activity than single agents alone in a subset of mutant KRAS cells, and the antitumor efficacy of ganetespib was potentiated by cotreatment with the PI3K/mTOR inhibitor BEZ235 in A549 xenografts in vivo. At the molecular level, ganetespib suppressed activating feedback signaling loops that occurred in response to MEK and PI3K/mTOR inhibition, although this activity was not the sole determinant of combinatorial benefit. In addition, ganetespib sensitized mutant KRAS NSCLC cells to standard-of-care chemotherapeutics of the antimitotic, topoisomerase inhibitor, and alkylating agent classes. Taken together, these data underscore the promise of ganetespib as a single-agent or combination treatment in KRAS-driven lung tumors. Mol Cancer Ther; 11(12); 2633–43. ©2012 AACR.
Data from Molecular and Biologic Analysis of Histone Deacetylase Inhibitors with Diverse Specificities
Authors: Newbold Andrea , Matthews Geoffrey M. , Bots Michael , Cluse Leonie A. , Clarke Christopher J.P. , Banks Kellie-Marie , Cullinane Carleen , Bolden Jessica E. , Christiansen Ailsa J. , Dickins Ross A. , Miccolo Claudia , Chiocca Susanna , Kral Astrid M. , Ozerova Nicole D. , Miller Thomas A. , Methot Joey L. , Richon Victoria M. , Secrist J. Paul , Minucci Saverio , Johnstone Ricky W.
Published: April 2023

Abstract
Histone deacetylase inhibitors (HDACi) are anticancer agents that induce hyperacetylation of histones, resulting in chromatin remodeling and transcriptional changes. In addition, nonhistone proteins, such as the chaperone protein Hsp90, are functionally regulated through hyperacetylation mediated by HDACis. Histone acetylation is thought to be primarily regulated by HDACs 1, 2, and 3, whereas the acetylation of Hsp90 has been proposed to be specifically regulated through HDAC6. We compared the molecular and biologic effects induced by an HDACi with broad HDAC specificity (vorinostat) with agents that predominantly inhibited selected class I HDACs (MRLB-223 and romidepsin). MRLB-223, a potent inhibitor of HDACs 1 and 2, killed tumor cells using the same apoptotic pathways as the HDAC 1, 2, 3, 6, and 8 inhibitor vorinostat. However, vorinostat induced histone hyperacetylation and killed tumor cells more rapidly than MRLB-223 and had greater therapeutic efficacy in vivo. FDCP-1 cells dependent on the Hsp90 client protein Bcr-Abl for survival, were killed by all HDACis tested, concomitant with caspase-dependent degradation of Bcr-Abl. These studies provide evidence that inhibition of HDAC6 and degradation of Bcr-Abl following hyperacetylation of Hsp90 is likely not a major mechanism of action of HDACis as had been previously posited. Mol Cancer Ther; 12(12); 2709–21. ©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: April 2023

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 SOD Mimetics: A Novel Class of Androgen Receptor Inhibitors That Suppresses Castration-Resistant Growth of Prostate Cancer
Authors: Thomas Rusha , Sharifi Nima
Published: April 2023

Abstract
Advanced prostate cancer is the second leading cause of cancer-related deaths among American men. The androgen receptor (AR) is vital for prostate cancer progression, even in the face of castrate levels of serum testosterone following androgen ablation therapy, a mainstay therapy for advanced prostate cancer. Downregulation of superoxide dismutase 2 (SOD2), a major intracellular antioxidant enzyme, occurs progressively during prostate cancer progression to advanced states and is known to promote AR activity in prostate cancer. Therefore, this study investigated the effects of SOD mimetics on AR expression and function in AR-dependent LNCaP, CWR22Rv1, and LAPC-4AD prostate cancer cells. Treatment with Tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl), a SOD mimetic, not only lowered cellular superoxide levels but also concomitantly attenuated AR transcriptional activity and AR target gene expression in a dose- and time-dependent manner, in the presence and absence of dihydrotestosterone, the major endogenous AR agonist. Inhibition of AR by Tempol was mediated, in large part, by its ability to decrease AR protein via increased degradation, in the absence of any inhibitory effects on other nuclear receptors. Inhibitory effects of Tempol on AR were also reproducible with other SOD mimetics, MnTBAP and MnTMPyP. Importantly, effects of Tempol on AR function were accompanied by significant in vitro and in vivo reduction in castration-resistant prostate cancer (CRPC) survival and growth. Collectively, this study has shown for the first time that SOD mimetics, by virtue of their ability to suppress AR function, may be beneficial in treating the currently incurable CRPC, in which SOD2 expression is highly suppressed. Mol Cancer Ther; 11(1); 87–97. ©2011 AACR.
Data from A Urokinase Receptor–Derived Peptide Inhibiting VEGF-Dependent Directional Migration and Vascular Sprouting
Authors: Bifulco Katia , Longanesi-Cattani Immacolata , Liguori Eleonora , Arra Claudio , Rea Domenica , Masucci Maria Teresa , De Rosa Mario , Pavone Vincenzo , Stoppelli Maria Patrizia , Carriero Maria Vincenza
Published: April 2023

Abstract
The receptor for the urokinase-type plasminogen activator (uPAR) is a widely recognized master regulator of cell migration, and uPAR88–92 is the minimal sequence required to induce cell motility. We previously showed that soluble forms of uPAR elicit angiogenic responses through their uPAR88–92 chemotactic sequence and that the synthetic peptide SRSRY exerts similar effects. By a drug design approach, based on the conformational analysis of the uPAR88–92 sequence, we developed peptides (pERERY, RERY, and RERF) that potently inhibit signaling triggered by uPAR88–92. In this study, we present evidence that these peptides are endowed also with a clear-cut antiangiogenic activity, although to different extents. The most active, RERF, prevents tube formation by human endothelial cells exposed to SRSRY. RERF also inhibits VEGF-triggered endothelial cell migration and cord-like formation in a dose-dependent manner, starting in the femtomolar range. RERF prevents F-actin polymerization, recruitment of αvβ3 integrin at focal adhesions, and αvβ3/VEGFR2 complex formation in endothelial cells exposed to VEGF. At molecular level, the inhibitory effect of RERF on VEGF signaling is shown by the decreased amount of phospho-FAK and phospho-Akt in VEGF-treated cells. In vivo, RERF prevents VEGF-dependent capillary sprouts originating from the host vessels that invaded angioreactors implanted in mice and neovascularization induced by subcorneal implantation of pellets containing VEGF in rabbits. Consistently, RERF reduced the growth and vascularization rate of tumors formed by HT1080 cells injected subcutaneously in the flanks of nude mice, indicating that RERF is a promising therapeutic agent for the control of diseases fuelled by excessive angiogenesis such as cancer. Mol Cancer Ther; 12(10); 1981–93. ©2013 AACR.
Data from Induction of the Transcriptional Repressor ZBTB4 in Prostate Cancer Cells by Drug-Induced Targeting of MicroRNA-17-92/106b-25 Clusters
Authors: Kim KyoungHyun , Chadalapaka Gayathri , Pathi Satya S. , Jin Un-Ho , Lee Ju-Seog , Park Yun-Yong , Cho Sung-Gook , Chintharlapalli Sudhakar , Safe Stephen
Published: April 2023

Abstract
Androgen-insensitive DU145 and PC3 human prostate cancer cells express high levels of specificity protein (Sp) transcription factors Sp1, Sp3, and Sp4, and treatment of cells with methyl 2-cyano-3,11-dioxo-18β-olean-1,12-dien-30-oate (CDODA-Me) inhibited cell growth and downregulated Sp1, Sp3, and Sp4 expression. CDODA-Me (15 mg/kg/d) was a potent inhibitor of tumor growth in a mouse xenograft model (PC3 cells) and also decreased expression of Sp transcription factors in tumors. CDODA-Me–mediated downregulation of Sp1, Sp3, and Sp4 was due to induction of the transcriptional repressor ZBTB4, which competitively binds and displaces Sp transcription factors from GC-rich sites in Sp1-, Sp3-, Sp4-, and Sp-regulated gene promoters. ZBTB4 levels are relatively low in DU145 and PC3 cells due to suppression by miR paralogs that are members of the miR-17-92 (miR-20a/17-5p) and miR-106b-25 (miR-106b/93) clusters. Examination of publically available prostate cancer patient array data showed an inverse relationship between ZBTB4 and miRs-20a/17-5p/106b/93 expression, and increased ZBTB4 in patients with prostate cancer was a prognostic factor for increased survival. CDODA-Me induces ZBTB4 in prostate cancer cells through disruption of miR–ZBTB4 interactions, and this results in downregulation of pro-oncogenic Sp transcription factors and Sp-regulated genes. Mol Cancer Ther; 11(9); 1852–62. ©2012 AACR.
Data from Neutralization of Prolactin Receptor Function by Monoclonal Antibody LFA102, a Novel Potential Therapeutic for the Treatment of Breast Cancer
Authors: Damiano Jason S. , Rendahl Katherine G. , Karim Christopher , Embry Millicent G. , Ghoddusi Majid , Holash Jocelyn , Fanidi Abdallah , Abrams Tinya J. , Abraham Judith A.
Published: April 2023

Abstract
Numerous lines of evidence suggest that the polypeptide hormone prolactin (PRL) may contribute to breast and prostate tumorigenesis through its interactions with the prolactin receptor (PRLR). Here, we describe the biologic properties of LFA102, a humanized neutralizing monoclonal antibody directed against the extracellular domain of PRLR. This antibody was found to effectively antagonize PRL-induced signaling in breast cancer cells in vitro and in vivo and to block PRL-induced proliferation in numerous cell line models, including examples of autocrine/paracrine PRL activity. A single administration of LFA102 resulted in regression of PRL-dependent Nb2-11 tumor xenografts and significantly prolonged time to progression. Finally, LFA102 treatment significantly inhibited PRLR signaling as well as tumor growth in a carcinogen-induced, estrogen receptor-positive rat mammary cancer model as a monotherapy and enhanced the efficacy of the aromatase inhibitor letrozole when administered in combination. The biologic properties of LFA102, elucidated by the preclinical studies presented here, suggest that this antibody has the potential to be a first-in-class, effective therapeutic for the treatment of PRL-dependent cancers. Mol Cancer Ther; 12(3); 295–305. ©2012 AACR.
Data from Tumor-Initiating Cells and FZD8 Play a Major Role in Drug Resistance in Triple-Negative Breast Cancer
Authors: Yin Shuping , Xu Liping , Bonfil R. Daniel , Banerjee Sanjeev , Sarkar Fazlul H. , Sethi Seema , Reddy Kaladhar B.
Published: April 2023

Abstract
Triple-negative breast cancer (TNBC) studies have shown that neoadjuvant chemotherapy before surgery was effective in the minority of women, whereas the majority who had residual tumor had a relatively poor outcome. To identify the mechanism by which residual cancer cells survive chemotherapy, we initially conducted gene expression profiling using the CRL2335 TNBC cell line derived from a squamous breast carcinoma before and after treatment with cisplatin plus TRAIL. We found a significant increase in the expression of FZD8, one of Wnt receptors, and its downstream targets LEF1 and TCF in residual CRL2335 tumor cells after treatment with cisplatin plus TRAIL. Increased FZD8 levels were further confirmed in other TNBC cell lines. Inhibition of FZD8 by siRNA in CRL2335 cells in the presence of cisplatin plus TRAIL reduced β-catenin and survivin levels and increased apoptosis compared with scrambled siRNA–treated cells. In vivo data show that cisplatin plus TRAIL treatment significantly reduces tumor volume in NOD/SCID mice. However, we found that cisplatin plus TRAIL treatment predominantly eliminated non–tumor-initiating cells, as shown by whole-body fluorescent imaging of mice injected with mammosphere-forming CRL2335 cells stably transfected with DsRed. This led to TIC enrichment in residual tumors, as confirmed by immunostaining for TIC markers. Moreover, an increase in FZD8 expression was observed in residual tumors treated with cisplatin and TRAIL. Taken together, our findings suggest that FZD8-mediated Wnt signaling may play a major role in mediating resistance to chemotherapy, making it a potential target to enhance chemotherapeutic efficacy in patients with TNBCs. Mol Cancer Ther; 12(4); 491–8. ©2013 AACR.
Data from Preclinical Development of the Novel Chk1 Inhibitor SCH900776 in Combination with DNA-Damaging Agents and Antimetabolites
Authors: Montano Ryan , Chung Injae , Garner Kristen M. , Parry David , Eastman Alan
Published: April 2023

Abstract
Many anticancer agents damage DNA and arrest cell-cycle progression primarily in S or G2 phase of the cell cycle. Previous studies with the topoisomerase I inhibitor SN38 have shown the efficacy of the Chk1 inhibitor UCN-01 to overcome this arrest and induce mitotic catastrophe. UCN-01 was limited in clinical trials by unfavorable pharmacokinetics. SCH900776 is a novel and more selective Chk1 inhibitor that potently inhibits Chk1 and abrogates cell-cycle arrest induced by SN38. Like UCN-01, abrogation of SN38-induced arrest enhances the rate of cell death but does not increase overall cell death. In contrast, SCH900776 reduced the growth-inhibitory concentration of hydroxyurea by 20- to 70-fold. A similar magnitude of sensitization was observed with cytarabine. A 5- to 10-fold sensitization occurred with gemcitabine, but no sensitization occurred with cisplatin, 5-fluorouracil, or 6-thioguanine. Sensitization occurred at hydroxyurea concentrations that marginally slowed DNA replication without apparent activation of Chk1, but this led to dependence on Chk1 that increased with time. For example, when added 18 hours after hydroxyurea, SCH900776 induced DNA double-strand breaks consistent with rapid collapse of replication forks. In addition, some cell lines were highly sensitive to SCH900776 alone, and these cells required lower concentrations of SCH900776 to sensitize them to hydroxyurea. We conclude that some tumors may be very sensitive to the combination of SCH900776 and hydroxyurea. Delayed administration of SCH900776 may be more effective than concurrent treatment. SCH900776 is currently in phase I clinical trials, and these results provide the rationale and schedule for future clinical trials. Mol Cancer Ther; 11(2); 427–38. ©2011 AACR.
Data from Sorafenib-Induced Hepatocellular Carcinoma Cell Death Depends on Reactive Oxygen Species Production In Vitro and In Vivo
Authors: Coriat Romain , Nicco Carole , Chéreau Christiane , Mir Olivier , Alexandre Jérôme , Ropert Stanislas , Weill Bernard , Chaussade Stanislas , Goldwasser François , Batteux Frédéric
Published: April 2023

Abstract
Sorafenib is presently the only effective therapy in advanced hepatocellular carcinoma (HCC). Because most anticancer drugs act, at least in part, through the generation of reactive oxygen species, we investigated whether sorafenib can induce an oxidative stress. The effects of sorafenib on intracellular ROS production and cell death were assessed in vitro in human (HepG2) and murine (Hepa 1.6) HCC cell lines and human endothelial cells (HUVEC) as controls. In addition, 26 sera from HCC patients treated by sorafenib were analyzed for serum levels of advanced oxidation protein products (AOPP). Sorafenib significantly and dose-dependently enhanced in vitro ROS production by HCC cells. The SOD mimic MnTBAP decreased sorafenib-induced lysis of HepG2 cells by 20% and of Hepa 1.6 cells by 75% compared with HCC cells treated with 5 mg/L sorafenib alone. MnTBAP significantly enhanced by 25% tumor growth in mice treated by sorafenib. On the other hand, serum levels of AOPP were higher in HCC patients treated by sorafenib than in sera collected before treatment (P < 0.001). An increase in serum AOPP concentration ≥0.2 μmol/L chloramine T equivalent after 15 days of treatment is a predictive factor for sorafenib response with higher progression free survival (P < 0.05) and overall survival rates (P < 0.05). As a conclusion, sorafenib dose-dependently induces the generation of ROS in tumor cells in vitro and in vivo. The sera of Sorafenib-treated HCC patients contain increased AOPP levels that are correlated with the clinical effectiveness of sorafenib and can be used as a marker of effectiveness of the drug. Mol Cancer Ther; 11(10); 2284–93. ©2012 AACR.