bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Poziotinib Inhibits HER2-Mutant–Driven Therapeutic Resistance and Multiorgan Metastasis in Breast Cancer
Authors: Kalra Rashi , Chen Ching Hui , Wang Junkai , Salam Ahmad Bin , Dobrolecki Lacey E. , Lewis Alaina , Sallas Christina , Yates Clayton C. , Gutierrez Carolina , Karanam Balasubramanyam , Anurag Meenakshi , Lim Bora , Ellis Matthew J. , Kavuri Shyam M.
Published: March 2024

Abstract
The pan-HER tyrosine kinase inhibitor (TKI) neratinib is therapeutically active against metastatic breast cancers harboring activating HER2 mutations, but responses are variable and often not durable. Here we demonstrate that recurrent HER2 mutations have differential effects on endocrine therapy responsiveness, metastasis, and pan-HER TKI therapeutic sensitivity. The prevalence and prognostic significance may also depend on whether the HER2 mutant has arisen in the context of lobular versus ductal histology. The most highly recurrent HER2 mutant, L755S, was particularly resistant to neratinib but sensitive to the pan-HER TKI poziotinib, alone or in combination with fulvestrant. Poziotinib reduced tumor growth, diminished multiorgan metastasis, and inhibited mTOR activation more effectively than neratinib. Similar therapeutic effects of poziotinib were observed in both an engineered HER2L755S MCF7 model and a patient-derived xenograft harboring a HER2G778_P780dup mutation. Overall, these findings support the need for clinical evaluation of poziotinib for the treatment of HER2-mutant metastatic breast cancer.
Significance:
Evaluation of the functional impact of HER2 mutations on therapy-induced resistance and metastasis identifies robust antitumor activity of poziotinib and supports the clinical evaluation of poziotinib in ER+ HER2 mutant breast cancer.
Data from Targeting Plk1 Sensitizes Pancreatic Cancer to Immune Checkpoint Therapy
Authors: Zhang Zhuangzhuang , Cheng Lijun , Li Jie , Qiao Qi , Karki Anju , Allison Derek B. , Shaker Nuha , Li Kunyu , Utturkar Sagar M. , Atallah Lanman Nadia M. , Rao Xiongjian , Rychahou Piotr , He Daheng , Konieczny Stephen F. , Wang Chi , Shao Qing , Evers B. Mark , Liu Xiaoqi
Published: March 2024

Abstract
Polo-like kinase 1 (Plk1) plays an important role in cell-cycle regulation. Recent work has suggested that Plk1 could be a biomarker of gemcitabine response in pancreatic ductal adenocarcinoma (PDAC). Although targeting Plk1 to treat PDAC has been attempted in clinical trials, the results were not promising, and the mechanisms of resistance to Plk1 inhibition is poorly understood. In addition, the role of Plk1 in PDAC progression requires further elucidation. Here, we showed that Plk1 was associated with poor outcomes in patients with PDAC. In an inducible transgenic mouse line with specific expression of Plk1 in the pancreas, Plk1 overexpression significantly inhibited caerulein-induced acute pancreatitis and delayed development of acinar-to-ductal metaplasia and pancreatic intraepithelial neoplasia. Bioinformatics analyses identified the regulatory networks in which Plk1 is involved in PDAC disease progression, including multiple inflammation-related pathways. Unexpectedly, inhibition or depletion of Plk1 resulted in upregulation of PD-L1 via activation of the NF-κB pathway. Mechanistically, Plk1-mediated phosphorylation of RB at S758 inhibited the translocation of NF-κB to nucleus, inactivating the pathway. Inhibition of Plk1 sensitized PDAC to immune checkpoint blockade therapy through activation of an antitumor immune response. Together, Plk1 suppresses PDAC progression and inhibits NF-κB activity, and targeting Plk1 can potentiate the efficacy of immunotherapy in PDAC.
Significance:
Inhibition of Plk1 induces upregulation of PD-L1 expression in pancreatic ductal adenocarcinoma, stimulating antitumor immunity and sensitizing tumors to immunotherapy.
Data from A Protumorigenic mDia2–MIRO1 Axis Controls Mitochondrial Positioning and Function in Cancer-Associated Fibroblasts
Authors: Cangkrama Michael , Liu Huan , Whipman James , Zubair Maria , Matsushita Mai , Di Filippo Michela , Kopf Manfred , Innocenti Metello , Werner Sabine
Published: March 2024

Abstract
Cancer-associated fibroblasts (CAF) are key regulators of tumorigenesis. Further insights into the tumor-promoting mechanisms of action of CAFs could help improve cancer diagnosis and treatment. Here we show that the formin mDia2 regulates the positioning and function of mitochondria in dermal fibroblasts, thereby promoting a protumorigenic CAF phenotype. Mechanistically, mDia2 stabilized the mitochondrial trafficking protein MIRO1. Loss of mDia2 or MIRO1 in fibroblasts or CAFs reduced the presence of mitochondria and ATP levels near the plasma membrane and at CAF-tumor cell contact sites, caused metabolic alterations characteristic of mitochondrial dysfunction, and suppressed the secretion of protumorigenic proteins. In mouse models of squamous carcinogenesis, genetic or pharmacologic inhibition of mDia2, MIRO1, or their common upstream regulator activin A inhibited tumor formation. Consistently, co-upregulation of mDia2 and MIRO1 in the stroma of various human cancers negatively correlated with survival. This work unveils a key role of mitochondria in the protumorigenic CAF phenotype and identifies an activin A–mDia2–MIRO1 signaling axis in CAFs with diagnostic and therapeutic potential.
Significance:
Inhibition of mDia2/MIRO1-mediated mitochondrial positioning in CAFs induces mitochondrial dysfunction and suppresses tumor growth, revealing a promising therapeutic strategy to target tumor–stroma cross-talk.
Data from An Immunogenic Model of KRAS-Mutant Lung Cancer Enables Evaluation of Targeted Therapy and Immunotherapy Combinations
Authors: Boumelha Jesse , de Carné Trécesson Sophie , Law Emily K. , Romero-Clavijo Pablo , Coelho Matthew A. , Ng Kevin W. , Mugarza Edurne , Moore Christopher , Rana Sareena , Caswell Deborah R. , Murillo Miguel , Hancock David C. , Argyris Prokopios P. , Brown William L. , Durfee Cameron , Larson Lindsay K. , Vogel Rachel I. , Suárez-Bonnet Alejandro , Priestnall Simon L. , East Philip , Ross Sarah J. , Kassiotis George , Molina-Arcas Miriam , Swanton Charles , Harris Reuben , Downward Julian
Published: March 2024

Abstract
Mutations in oncogenes such as KRAS and EGFR cause a high proportion of lung cancers. Drugs targeting these proteins cause tumor regression but ultimately fail to elicit cures. As a result, there is an intense interest in how to best combine targeted therapies with other treatments, such as immunotherapies. However, preclinical systems for studying the interaction of lung tumors with the host immune system are inadequate, in part due to the low tumor mutational burden in genetically engineered mouse models. Here we set out to develop mouse models of mutant KRAS–driven lung cancer with an elevated tumor mutational burden by expressing the human DNA cytosine deaminase, APOBEC3B, to mimic the mutational signature seen in human lung cancer. This failed to substantially increase clonal tumor mutational burden and autochthonous tumors remained refractory to immunotherapy. However, establishing clonal cell lines from these tumors enabled the generation of an immunogenic syngeneic transplantation model of KRAS-mutant lung adenocarcinoma that was sensitive to immunotherapy. Unexpectedly, antitumor immune responses were not directed against neoantigens but instead targeted derepressed endogenous retroviral antigens. The ability of KRASG12C inhibitors to cause regression of KRASG12C -expressing tumors was markedly potentiated by the adaptive immune system, highlighting the importance of using immunocompetent models for evaluating targeted therapies. Overall, this model provides a unique opportunity for the study of combinations of targeted and immunotherapies in immune-hot lung cancer.
Significance:
This study develops a mouse model of immunogenic KRAS-mutant lung cancer to facilitate the investigation of optimal combinations of targeted therapies with immunotherapies.
Data from Aberrant L-Fucose Accumulation and Increased Core Fucosylation Are Metabolic Liabilities in Mesenchymal Glioblastoma
Authors: Pieri Valentina , Gallotti Alberto L. , Drago Denise , Cominelli Manuela , Pagano Ilaria , Conti Valentina , Valtorta Silvia , Coliva Angela , Lago Sara , Michelatti Daniela , Massimino Luca , Ungaro Federica , Perani Laura , Spinelli Antonello , Castellano Antonella , Falini Andrea , Zippo Alessio , Poliani Pietro L. , Moresco Rosa Maria , Andolfo Annapaola , Galli Rossella
Published: March 2024

Abstract
Glioblastoma (GBM) is a common and deadly form of brain tumor in adults. Dysregulated metabolism in GBM offers an opportunity to deploy metabolic interventions as precise therapeutic strategies. To identify the molecular drivers and the modalities by which different molecular subgroups of GBM exploit metabolic rewiring to sustain tumor progression, we interrogated the transcriptome, the metabolome, and the glycoproteome of human subgroup-specific GBM sphere-forming cells (GSC). L-fucose abundance and core fucosylation activation were elevated in mesenchymal (MES) compared with proneural GSCs; this pattern was retained in subgroup-specific xenografts and in subgroup-affiliated human patient samples. Genetic and pharmacological inhibition of core fucosylation significantly reduced tumor growth in MES GBM preclinical models. Liquid chromatography-mass spectrometry (LC-MS)–based glycoproteomic screening indicated that most MES-restricted core-fucosylated proteins are involved in therapeutically relevant GBM pathological processes, such as extracellular matrix interaction, cell adhesion, and integrin-mediated signaling. Selective L-fucose accumulation in MES GBMs was observed using preclinical minimally invasive PET, implicating this metabolite as a potential subgroup-restricted biomarker.

Overall, these findings indicate that L-fucose pathway activation in MES GBM is a subgroup-specific dependency that could provide diagnostic markers and actionable therapeutic targets.
Significance:
Metabolic characterization of subgroup-specific glioblastoma (GBM) sphere-forming cells identifies the L-fucose pathway as a vulnerability restricted to mesenchymal GBM, disclosing a potential precision medicine strategy for targeting cancer metabolism.
Data from MYC Overexpression Drives Immune Evasion in Hepatocellular Carcinoma That Is Reversible through Restoration of Proinflammatory Macrophages
Authors: Dhanasekaran Renumathy , Hansen Aida S. , Park Jangho , Lemaitre Lea , Lai Ian , Adeniji Nia , Kuruvilla Sibu , Suresh Akanksha , Zhang Josephine , Swamy Varsha , Felsher Dean W.
Published: March 2024

Abstract
Cancers evade immune surveillance, which can be reversed through immune-checkpoint therapy in a small subset of cases. Here, we report that the MYC oncogene suppresses innate immune surveillance and drives resistance to immunotherapy. In 33 different human cancers, MYC genomic amplification and overexpression increased immune-checkpoint expression, predicted nonresponsiveness to immune-checkpoint blockade, and was associated with both Th2-like immune profile and reduced CD8 T-cell infiltration. MYC transcriptionally suppressed innate immunity and MHCI-mediated antigen presentation, which in turn impeded T-cell response. Combined, but not individual, blockade of PDL1 and CTLA4 could reverse MYC-driven immune suppression by leading to the recruitment of proinflammatory antigen-presenting macrophages with increased CD40 and MHCII expression. Depletion of macrophages abrogated the antineoplastic effects of PDL1 and CTLA4 blockade in MYC-driven hepatocellular carcinoma (HCC). Hence, MYC is a predictor of immune-checkpoint responsiveness and a key driver of immune evasion through the suppression of proinflammatory macrophages. The immune evasion induced by MYC in HCC can be overcome by combined PDL1 and CTLA4 blockade.
Significance:
Macrophage-mediated immune evasion is a therapeutic vulnerability of MYC-driven cancers, which has implications for prioritizing MYC-driven hepatocellular carcinoma for combination immunotherapy.
Data from Inhibition of Focal Adhesion Kinase by PF-562,271 Inhibits the Growth and Metastasis of Pancreatic Cancer Concomitant with Altering the Tumor Microenvironment
Authors: Stokes Jayme B. , Adair Sara J. , Slack-Davis Jill K. , Walters Dustin M. , Tilghman Robert W. , Hershey E. Dan , Lowrey Bryce , Thomas Keena S. , Bouton Amy H. , Hwang Rosa F. , Stelow Edward B. , Parsons J. Thomas , Bauer Todd W.
Published: March 2024

Abstract
Current therapies for pancreatic ductal adenocarcinoma (PDA) target individual tumor cells. Focal adhesion kinase (FAK) is activated in PDA, and levels are inversely associated with survival. We investigated the effects of PF-562,271 (a small-molecule inhibitor of FAK/PYK2) on (i) in vitro migration, invasion, and proliferation; (ii) tumor proliferation, invasion, and metastasis in a murine model; and (iii) stromal cell composition in the PDA microenvironment. Migration assays were conducted to assess tumor and stromal cell migration in response to cellular factors, collagen, and the effects of PF-562,271. An orthotopic murine model was used to assess the effects of PF-562,271 on tumor growth, invasion, and metastasis. Proliferation assays measured PF-562,271 effects on in vitro growth. Immunohistochemistry was used to examine the effects of FAK inhibition on the cellular composition of the tumor microenvironment. FAK and PYK2 were activated and expressed in patient-derived PDA tumors, stromal components, and human PDA cell lines. PF-562,271 blocked phosphorylation of FAK (phospho-FAK or Y397) in a dose-dependent manner. PF-562,271 inhibited migration of tumor cells, cancer-associated fibroblasts, and macrophages. Treatment of mice with PF-562,271 resulted in reduced tumor growth, invasion, and metastases. PF-562,271 had no effect on tumor necrosis, angiogenesis, or apoptosis, but it did decrease tumor cell proliferation and resulted in fewer tumor-associated macrophages and fibroblasts than control or gemcitabine. These data support a role for FAK in PDA and suggest that inhibitors of FAK may contribute to efficacious treatment of patients with PDA. Mol Cancer Ther; 10(11); 2135–45. ©2011 AACR.
Data from Combination Radioimmunotherapy and Chemoimmunotherapy Involving Different or the Same Targets Improves Therapy of Human Pancreatic Carcinoma Xenograft Models
Authors: Sharkey Robert M. , Karacay Habibe , Govindan Serengulam V. , Goldenberg David M.
Published: March 2024

Abstract
Chemoimmunotherapy with antibody–drug conjugates (ADC) is emerging as a promising therapy for solid tumors, whereas radioimmunotherapy (RAIT) of solid tumors has been relatively ineffective because of their resistance to radiation. We developed antibody–SN-38 conjugates that have significant antitumor activity in xenograft models at nontoxic doses. The goal of this study was to determine if an ADC could be combined with RAIT to enhance efficacy without a commensurate increase in host toxicity. Nude mice bearing human pancreatic cancer xenografts (Capan-1 and BxPC-3) were treated with a single dose of 90Y-labeled antimucin antibody (hPAM4; clivatuzumab tetraxetan) alone or in combination with an anti-Trop-2–SN-38 conjugate, typically administered twice weekly over 4 weeks. The combination, even at RAIT's maximum tolerated dose, controlled tumor progression and cured established xenografts significantly better than the individual treatments without appreciable toxicity. The ADC could be started 1 week after or up to 2 weeks before RAIT with similar enhanced responses, but delaying RAIT for 2 weeks after the ADC was less effective. A nonspecific ADC provided additional benefit over using free drug (irinotecan), but the response was enhanced with the specific ADC. When targeting Capan-1 with ample mucin, hPAM4 could be used as the RAIT and the ADC agent without losing effectiveness, but in BxPC-3 with less mucin, targeting of different antigens was preferred. These studies show the feasibility of combining ADC and RAIT for improved efficacy without increased toxicity. Mol Cancer Ther; 10(6); 1072–81. ©2011 AACR.
Data from 3,5-Bis(2,4-Difluorobenzylidene)-4-piperidone, a Novel Compound That Affects Pancreatic Cancer Growth and Angiogenesis
Authors: Subramaniam Dharmalingam , Nicholes Nathan D. , Dhar Animesh , Umar Shahid , Awasthi Vibhudutta , Welch Danny R. , Jensen Roy A. , Anant Shrikant
Published: March 2024

Abstract
Dysregulated Notch signaling plays an important role in the progression of cancer. Notch signaling affects tumor growth and angiogenesis through the actions of its ligand Jagged-1. In this study, we developed a novel compound 3,5-bis(2,4-difluorobenzylidene)-4-piperidone (DiFiD) and determined that it inhibits cancer cell growth and its effects on Notch signaling. Intraperitoneal administration of DiFiD significantly suppressed growth of pancreatic cancer tumor xenografts. There was a reduction in CD31-positive blood vessels, suggesting that there was an effect on angiogenesis. In vitro, DiFiD inhibited the proliferation of various human and mouse pancreatic cancer cells while increasing activated caspase-3. Cell-cycle analyses showed that DiFiD induced G2–M arrest and decreased the expression of cell-cycle–related proteins cyclin A1 and D1 while upregulating cyclin-dependent kinase inhibitor p21WAF1. We next determined the mechanism of action. DiFiD reduced Notch-1 activation, resulting in reduced expression of its downstream target protein Hes-1. We further determined that the reduced Notch-1 activation was due to reduction in the ligand Jagged-1 and two critical components of the γ-secretase enzyme complex presenilin-1 and nicastrin. Ectopic expression of the Notch intracellular domain rescued the cells from DiFiD-mediated growth suppression. DiFiD-treated tumor xenografts also showed reduced levels of Jagged-1 and the γ-secretase complex proteins presenilin-1 and nicastrin. Taken together, these data suggest that DiFiD is a novel potent therapeutic agent that can target different aspects of the Notch signaling pathway to inhibit both tumor growth and angiogenesis. Mol Cancer Ther; 10(11); 2146–56. ©2011 AACR.
Data from Honokiol in Combination with Radiation Targets Notch Signaling to Inhibit Colon Cancer Stem Cells
Authors: Ponnurangam Sivapriya , Mammen Joshua M.V. , Ramalingam Satish , He Zhiyun , Zhang Youcheng , Umar Shahid , Subramaniam Dharmalingam , Anant Shrikant
Published: March 2024

Abstract
Cancer stem cells are implicated in resistance to ionizing radiation (IR) and chemotherapy. Honokiol, a biphenolic compound has been used in traditional Chinese medicine for treating various ailments. In this study, we determined the ability of honokiol to enhance the sensitivity of colon cancer stem cells to IR. The combination of honokiol and IR suppressed proliferation and colony formation while inducing apoptosis of colon cancer cells in culture. There were also reduced numbers and size of spheroids, which was coupled with reduced expression of cancer stem cell marker protein DCLK1. Flow cytometry studies confirmed that the honokiol–IR combination reduced the number of DCLK1+ cells. In addition, there were reduced levels of activated Notch-1, its ligand Jagged-1, and the downstream target gene Hes-1. Furthermore, expression of components of the Notch-1 activating γ-secretase complex, presenilin 1, nicastrin, Pen2, and APH-1 was also suppressed. On the other hand, the honokiol effects were mitigated when the Notch intracellular domain was expressed. To determine the effect of honokiol–IR combination on tumor growth in vivo, nude mice tumor xenografts were administered honokiol intraperitoneally and exposed to IR. The honokiol–IR combination significantly inhibited tumor xenograft growth. In addition, there were reduced levels of DCLK1 and the Notch signaling–related proteins in the xenograft tissues. Together, these data suggest that honokiol is a potent inhibitor of colon cancer growth that targets the stem cells by inhibiting the γ-secretase complex and the Notch signaling pathway. These studies warrant further clinical evaluation for the combination of honokiol and IR for treating colon cancers. Mol Cancer Ther; 11(4); 963–72. ©2012 AACR.
Data from Engineering and Therapeutic Application of Single-Chain Bivalent TGF-β Family Traps
Authors: Zwaagstra John C. , Sulea Traian , Baardsnes Jason , Lenferink Anne E.G. , Collins Cathy , Cantin Christiane , Paul-Roc Béatrice , Grothe Suzanne , Hossain Sazzad , Richer Louis-Philippe , L'Abbé Denis , Tom Roseanne , Cass Brian , Durocher Yves , O'Connor-McCourt Maureen D.
Published: March 2024

Abstract
Deregulation of TGF-β superfamily signaling is a causative factor in many diseases. Here we describe a protein engineering strategy for the generation of single-chain bivalent receptor traps for TGF-β superfamily ligands. Traps were assembled using the intrinsically disordered regions flanking the structured binding domain of each receptor as "native linkers" between two binding domains. This yields traps that are approximately threefold smaller than antibodies and consists entirely of native receptor sequences. Two TGF-β type II receptor-based, single-chain traps were designed, termed (TβRII)2 and (TβRIIb)2, that have native linker lengths of 35 and 60 amino acids, respectively. Both single-chain traps exhibit a 100 to 1,000 fold higher in vitro ligand binding and neutralization activity compared with the monovalent ectodomain (TβRII-ED), and a similar or slightly better potency than pan–TGF-β–neutralizing antibody 1D11 or an Fc-fused receptor trap (TβRII-Fc). Despite its short in vivo half-life (<1 hour), which is primarily due to kidney clearance, daily injections of the (TβRII)2 trap reduced the growth of 4T1 tumors in BALB/c mice by 50%, an efficacy that is comparable with 1D11 (dosed thrice weekly). In addition, (TβRII)2 treatment of mice with established 4T1 tumors (100 mm3) significantly inhibited further tumor growth, whereas the 1D11 antibody did not. Overall, our results indicate that our rationally designed bivalent, single-chain traps have promising therapeutic potential. Mol Cancer Ther; 11(7); 1477–87. ©2012 AACR.
Data from A Novel Antiandrogen, Compound 30, Suppresses Castration-Resistant and MDV3100-Resistant Prostate Cancer Growth In Vitro and In Vivo
Authors: Kuruma Hidetoshi , Matsumoto Hiroaki , Shiota Masaki , Bishop Jennifer , Lamoureux Francois , Thomas Christian , Briere David , Los Gerrit , Gleave Martin , Fanjul Andrea , Zoubeidi Amina
Published: March 2024

Abstract
Resistance to antiandrogen drugs, like MDV3100, occurs in patients with castration-resistant prostate cancer (CRPC). Thus, preventing or treating antiandrogen resistance is a major clinical challenge. We identified a novel antiandrogen, Compound 30, and compared its efficacy with MDV3100. We found that Compound 30 inhibits androgen receptor (AR) activity in LNCaP cells, C4-2 cells, as well as MDV3100-resistant cell lines. Compared with MDV3100, Compound 30 treatment induces greater reduction in AR, prostate-specific antigen (PSA), and AR transcriptional activity, and prevents AR nuclear translocation in AR-sensitive LNCaP cells. Compound 30 has antiproliferative effects in LNCaP cells, in castrate-resistant C4-2 cells, and those resistant to MDV3100. Compound 30 was equally as effective as MDV3100 in reducing tumor volume and PSA in vivo. More importantly, Compound 30 is effective at inhibiting AR activity in MDV3100-resistant cell lines and significantly prevented tumor growth and PSA increases in mice bearing MDV3100-resistant xenografts. Together, our data show that Compound 30 strongly inhibited AR activity and suppressed castration-resistant LNCaP growth as well as MDV3100-resistant cell growth in vitro and in vivo. These data provide a preclinical proof-of-principle that Compound 30 could be a promising next generation anti-AR agent, especially in the context of antiandrogen-resistant tumors. Mol Cancer Ther; 12(5); 567–76. ©2013 AACR.
Data from CTLA-4 Blockade Expands Infiltrating T Cells and Inhibits Cancer Cell Repopulation during the Intervals of Chemotherapy in Murine Mesothelioma
Authors: Wu Licun , Yun Zhihong , Tagawa Tetsuzo , Rey-McIntyre Katrina , de Perrot Marc
Published: March 2024

Abstract
Cancer immunotherapy has shown promising results when combined with chemotherapy. Blocking CTLA-4 signaling by monoclonal antibody between cycles of chemotherapy may inhibit cancer cell repopulation and enhance the antitumoral immune reaction, thus improve the efficacy of chemotherapy in mesothelioma. The impact of CTLA-4 blockade on the early stage of tumor development was evaluated in a subcutaneous murine mesothelioma model. CTLA-4 blocking antibody was administered following each cycle of chemotherapy, and monotherapy was included as controls. Antitumor effect was evaluated by tumor growth delay and survival of the animals. Tumor cell repopulation was quantified by bromodeoxyuridine incorporation and Ki67 by immunohistochemistry and/or flow cytometry. In vitro cell killing was determined by classic chromium-released assay, and reverse transcription PCR (RT-PCR) was carried out to determine the gene expression of associated cytokines. Anti-CTLA-4 monoclonal antibody was able to inhibit tumor growth at early stage of tumor development. Antitumor effect was achieved by administration of CTLA-4 blockade between cycles of chemotherapy. Tumor cell repopulation during the intervals of cisplatin was inhibited by CTLA-4 blockade. Anti-CTLA-4 therapy gave rise to an increased number of CD4 and CD8 T cells infiltrating the tumor. RT-PCR showed that the gene expression of interleukin IL-2, IFN-γ, granzyme B, and perforin increased in the tumor milieu. Blockade of CTLA-4 signaling showed effective anticancer effect, correlating with inhibiting cancer cell repopulation between cycles of chemotherapy and upregulating tumor-infiltrating T lymphocytes, cytokines, and cytolytic enzymes in a murine mesothelioma model. Mol Cancer Ther; 11(8); 1809–19. ©2012 AACR.
Data from Receptor-Directed Chimeric Toxins Created by Sortase-Mediated Protein Fusion
Authors: McCluskey Andrew J. , Collier R. John
Published: March 2024

Abstract
Chimeric protein toxins that act selectively on cells expressing a designated receptor may serve as investigational probes and/or antitumor agents. Here, we report use of the enzyme sortase A (SrtA) to create four chimeric toxins designed to selectively kill cells bearing the tumor marker HER2. We first expressed and purified: (i) a receptor recognition-deficient form of diphtheria toxin that lacks its receptor-binding domain and (ii) a mutated, receptor-binding–deficient form of anthrax-protective antigen. Both proteins carried at the C terminus the sortase recognition sequence LPETGG and a H6 affinity tag. Each toxin protein was mixed with SrtA plus either of two HER2-recognition proteins—a single-chain antibody fragment or an Affibody—both carrying an N-terminal G5 tag. With wild-type SrtA, the fusion reaction between the toxin and receptor-recognition proteins approached completion only after several hours, whereas with an evolved form of the enzyme, SrtA*, the reaction was virtually complete within 5 minutes. The four fusion toxins were purified and shown to kill HER2-positive cells in culture with high specificity. Sortase-mediated ligation of binary combinations of diverse natively folded proteins offers a facile way to produce large sets of chimeric proteins for research and medicine. Mol Cancer Ther; 12(10); 2273–81. ©2013 AACR.
Data from Identification and Characterization of MEL-3, a Novel AR Antagonist That Suppresses Prostate Cancer Cell Growth
Authors: Helsen Christine , Marchand Arnaud , Chaltin Patrick , Munck Sebastian , Voet Arnout , Verstuyf Annemieke , Claessens Frank
Published: March 2024

Abstract
Antiandrogens are an important component of prostate cancer therapy as the androgen receptor (AR) is the key regulator of prostate cancer growth and survival. Current AR antagonists, such as bicalutamide and hydroxyflutamide, have a low affinity for the AR and as a result block AR signaling insufficiently. Moreover, many patients develop a resistance for bicalutamide or hydroxyflutamide during therapy or show a clinical improvement after withdrawal of the antiandrogen. New and more effective AR antagonists are needed to ensure follow-up of these patients. We therefore developed a screening system to identify novel AR antagonists from a collection of compounds. MEL-3 [8-(propan-2-yl)-5,6-dihydro-4H-pyrazino[3,2,1-jk]carbazole] was selected as potent inhibitor of the AR and was further characterized in vitro. On different prostate cancer cell lines MEL-3 displayed an improved therapeutic profile compared with bicalutamide. Not only cell growth was inhibited but also the expression of androgen-regulated genes: PSA and FKBP5. Prostate cancer is often associated with mutated ARs that respond to a broadened spectrum of ligands including the current antiandrogens used in the clinic, hydroxyflutamide and bicalutamide. The activity of two mutant receptors (AR T877A and AR W741C) was shown to be reduced in presence of MEL-3, providing evidence that MEL-3 can potentially be a follow-up treatment for bicalutamide- and hydroxyflutamide-resistant patients. The mechanism of action of MEL-3 on the molecular level was further explored by comparing the structure–activity relationship of different chemical derivatives of MEL-3 with the in silico docking of MEL-3 derivatives in the binding pocket of the AR. Mol Cancer Ther; 11(6); 1257–68. ©2012 AACR.
Data from Thermal Targeting of an Acid-Sensitive Doxorubicin Conjugate of Elastin-like Polypeptide Enhances the Therapeutic Efficacy Compared with the Parent Compound In Vivo
Authors: Moktan Shama , Perkins Eddie , Kratz Felix , Raucher Drazen
Published: March 2024

Abstract
Elastin-like polypeptides (ELP) aggregate in response to mild hyperthermia, but remain soluble under normal physiologic conditions. ELP macromolecules can accumulate in solid tumors because of the enhanced permeability and retention effect. Tumor retention of ELPs can be further enhanced through hyperthermia-induced aggregation of ELPs by local heating of the tumor. We evaluated the therapeutic potential of ELPs in delivering doxorubicin in the E0771 syngeneic mouse breast cancer model. The ELP-Dox conjugate consisted of a cell-penetrating peptide at the N-terminus and the 6-maleimidocaproyl hydrazone derivative of doxorubicin at the C-terminus of ELP. The acid-sensitive hydrazone linker ensured release of doxorubicin in the lysosomes/endosomes after cellular uptake of the drug conjugate. ELP-Dox dosed at 5 mg doxorubicin equivalent/kg, extended the plasma half-life of doxorubicin to 5.5 hours. In addition, tumor uptake of ELP-Dox increased 2-fold when hyperthermia was applied, and was also enhanced compared to free doxorubicin. Although high levels of doxorubicin were found in the heart of animals treated with free doxorubicin, no detectable levels of doxorubicin were found in ELP-Dox–treated animals, indicating a correlation between tumor targeting and reduction of potential cardiac toxicity by ELP-Dox. At an optimal dose of 12 mg doxorubicin equivalent/kg, ELP-Dox in combination with hyperthermia induced a complete tumor growth inhibition, which was distinctly superior to free drug that only moderately inhibited tumor growth. In summary, our findings show that thermal targeting of ELP increases the potency of doxorubicin underlying the potential of exploiting ELPs to enhance the therapeutic efficacy of conventional anticancer drugs. Mol Cancer Ther; 11(7); 1547–56. ©2012 AACR.
Data from Restoration of miR-200c to Ovarian Cancer Reduces Tumor Burden and Increases Sensitivity to Paclitaxel
Authors: Cittelly Diana M. , Dimitrova Irina , Howe Erin N. , Cochrane Dawn R. , Jean Annie , Spoelstra Nicole S. , Post Miriam D. , Lu Xian , Broaddus Russell R. , Spillman Monique A. , Richer Jennifer K.
Published: March 2024

Abstract
A therapeutic intervention that could decrease tumor burden and increase sensitivity to chemotherapy would have a significant impact on the high morbidity rate associated with ovarian cancer. miRNAs have emerged as potential therapeutic candidates due to their ability to downregulate multiple targets involved in tumor progression and chemoresistance. miRNA-200c (miR-200c) is downregulated in ovarian cancer cell lines and stage III ovarian tumors, and low miR-200c correlates with poor prognosis. miR-200c increases sensitivity to taxanes in vitro by targeting class III β-tubulin gene (TUBB3), a tubulin known to mediate chemoresistance. Indeed, we find that patients with tumors having low TUBB3 had significantly prolonged survival (average survival 52.73 ± 4.08 months) as compared with those having high TUBB3 (average survival 42.56 ± 3.19 months). miR-200c also targets TrkB, a mediator of resistance to anoikis. We show that restoration of miR-200c to ovarian cancer cells results in increased anoikis sensitivity and reduced adherence to biologic substrates in vitro. Because both chemo- and anoikis-resistance are critical steps in the progression of ovarian cancer, we sought to determine how restoration of miR-200c affects tumor burden and chemosensitivity in an in vivo preclinical model of ovarian cancer. Restoration of miR-200c in an intraperitoneal xenograft model of human ovarian cancer results in decreased tumor formation and tumor burden. Furthermore, even in established tumors, restoration of miR-200c, alone or in combination with paclitaxel, results in significantly decreased tumor burden. Our study suggests that restoration of miR-200c immediately before cytotoxic chemotherapy may allow for a better response or lower effective dose. Mol Cancer Ther; 11(12); 2556–65. ©2012 AACR.
Data from HGF as a Circulating Biomarker of Onartuzumab Treatment in Patients with Advanced Solid Tumors
Authors: Penuel Elicia , Li Congfen , Parab Vaishali , Burton Luciana , Cowan Kyra J. , Merchant Mark , Yauch Robert L. , Patel Premal , Peterson Amy , Hampton Garret M. , Lackner Mark R. , Hegde Priti S.
Published: March 2024

Abstract
The objective of this study was to evaluate circulating hepatocyte growth factor (cHGF) as a pharmacodynamic biomarker of Met inhibition for onartuzumab (MetMAb, OA5D5v2) in a phase I trial in patients with advanced cancers and a phase II trial in non–small cell lung cancer (NSCLC). The phase I study was a dose escalation trial with onartuzumab administered i.v. once every three weeks. The phase II study was a randomized two-arm trial in which onartuzumab or placebo was administered in combination with erlotinib in 137 patients with second and third line (2/3L) NSCLC. cHGF levels were evaluated by ELISA at multiple time points over the treatment period. Onartuzumab administration resulted in an acute and sustained rise in cHGF in both the phase I and phase II studies. Elevation in cHGF was independent of dose or drug exposure and was restricted to onartuzumab treatment. Neither higher baseline nor elevated change in cHGF levels upon treatment could simply be attributed to tumor burden or number of liver metastasis. We have shown that elevated cHGF can consistently and reproducibly be measured as a pharmacodynamic biomarker of onartuzumab activity. The elevation in cHGF is independent of tumor type, dose administered, or dose duration. Although these studies were not powered to directly address the contribution of cHGF as a predictive, on-treatment, circulating biomarker, these data suggest that measurement of cHGF in future expanded studies is warranted. Mol Cancer Ther; 12(6); 1122–30. ©2013 AACR.
Data from A Pragmatic Definition of Therapeutic Synergy Suitable for Clinically Relevant In Vitro Multicompound Analyses
Authors: Kashif Muhammad , Andersson Claes , Åberg Magnus , Nygren Peter , Sjöblom Tobias , Hammerling Ulf , Larsson Rolf , Gustafsson Mats G.
Published: March 2024

Abstract
For decades, the standard procedure when screening for candidate anticancer drug combinations has been to search for synergy, defined as any positive deviation from trivial cases like when the drugs are regarded as diluted versions of each other (Loewe additivity), independent actions (Bliss independence), or no interaction terms in a response surface model (no interaction). Here, we show that this kind of conventional synergy analysis may be completely misleading when the goal is to detect if there is a promising in vitro therapeutic window. Motivated by this result, and the fact that a drug combination offering a promising therapeutic window seldom is interesting if one of its constituent drugs can provide the same window alone, the largely overlooked concept of therapeutic synergy (TS) is reintroduced. In vitro TS is said to occur when the largest therapeutic window obtained by the best drug combination cannot be achieved by any single drug within the concentration range studied. Using this definition of TS, we introduce a procedure that enables its use in modern massively parallel experiments supported by a statistical omnibus test for TS designed to avoid the multiple testing problem. Finally, we suggest how one may perform TS analysis, via computational predictions of the reference cell responses, when only the target cell responses are available. In conclusion, the conventional error-prone search for promising drug combinations may be improved by replacing conventional (toxicology-rooted) synergy analysis with an analysis focused on (clinically motivated) TS. Mol Cancer Ther; 13(7); 1964–76. ©2014 AACR.
Data from Small Molecule Inhibition of PAX3-FOXO1 through AKT Activation Suppresses Malignant Phenotypes of Alveolar Rhabdomyosarcoma
Authors: Jothi Mathivanan , Mal Munmun , Keller Charles , Mal Asoke K.
Published: March 2024

Abstract
Alveolar rhabdomyosarcoma comprises a rare highly malignant tumor presumed to be associated with skeletal muscle lineage in children. The hallmark of the majority of alveolar rhabdomyosarcoma is a chromosomal translocation that generates the PAX3-FOXO1 fusion protein, which is an oncogenic transcription factor responsible for the development of the malignant phenotype of this tumor. Alveolar rhabdomyosarcoma cells are dependent on the oncogenic activity of PAX3-FOXO1, and its expression status in alveolar rhabdomyosarcoma tumors correlates with worst patient outcome, suggesting that blocking this activity of PAX3-FOXO1 may be an attractive therapeutic strategy against this fusion-positive disease. In this study, we screened small molecule chemical libraries for inhibitors of PAX3-FOXO1 transcriptional activity using a cell-based readout system. We identified the Sarco/endoplasmic reticulum Ca2+-ATPases (SERCA) inhibitor thapsigargin as an effective inhibitor of PAX3-FOXO1. Subsequent experiments in alveolar rhabdomyosarcoma cells showed that activation of AKT by thapsigargin inhibited PAX3-FOXO1 activity via phosphorylation. Moreover, this AKT activation appears to be associated with the effects of thapsigargin on intracellular calcium levels. Furthermore, thapsigargin inhibited the binding of PAX3-FOXO1 to target genes and subsequently promoted its proteasomal degradation. In addition, thapsigargin treatment decreases the growth and invasive capacity of alveolar rhabdomyosarcoma cells while inducing apoptosis in vitro. Finally, thapsigargin can suppress the growth of an alveolar rhabdomyosarcoma xenograft tumor in vivo. These data reveal that thapsigargin-induced activation of AKT is an effective mechanism to inhibit PAX3-FOXO1 and a potential agent for targeted therapy against alveolar rhabdomyosarcoma. Mol Cancer Ther; 12(12); 2663–74. ©2013 AACR.
Data from Selective Inhibition of EZH2 by EPZ-6438 Leads to Potent Antitumor Activity in EZH2-Mutant Non-Hodgkin Lymphoma
Authors: Knutson Sarah K. , Kawano Satoshi , Minoshima Yukinori , Warholic Natalie M. , Huang Kuan-Chun , Xiao Yonghong , Kadowaki Tadashi , Uesugi Mai , Kuznetsov Galina , Kumar Namita , Wigle Tim J. , Klaus Christine R. , Allain Christina J. , Raimondi Alejandra , Waters Nigel J. , Smith Jesse J. , Porter-Scott Margaret , Chesworth Richard , Moyer Mikel P. , Copeland Robert A. , Richon Victoria M. , Uenaka Toshimitsu , Pollock Roy M. , Kuntz Kevin W. , Yokoi Akira , Keilhack Heike
Published: March 2024

Abstract
Mutations within the catalytic domain of the histone methyltransferase EZH2 have been identified in subsets of patients with non-Hodgkin lymphoma (NHL). These genetic alterations are hypothesized to confer an oncogenic dependency on EZH2 enzymatic activity in these cancers. We have previously reported the discovery of EPZ005678 and EPZ-6438, potent and selective S-adenosyl-methionine-competitive small molecule inhibitors of EZH2. Although both compounds are similar with respect to their mechanism of action and selectivity, EPZ-6438 possesses superior potency and drug-like properties, including good oral bioavailability in animals. Here, we characterize the activity of EPZ-6438 in preclinical models of NHL. EPZ-6438 selectively inhibits intracellular lysine 27 of histone H3 (H3K27) methylation in a concentration- and time-dependent manner in both EZH2 wild-type and mutant lymphoma cells. Inhibition of H3K27 trimethylation (H3K27Me3) leads to selective cell killing of human lymphoma cell lines bearing EZH2 catalytic domain point mutations. Treatment of EZH2-mutant NHL xenograft-bearing mice with EPZ-6438 causes dose-dependent tumor growth inhibition, including complete and sustained tumor regressions with correlative diminution of H3K27Me3 levels in tumors and selected normal tissues. Mice dosed orally with EPZ-6438 for 28 days remained tumor free for up to 63 days after stopping compound treatment in two EZH2-mutant xenograft models. These data confirm the dependency of EZH2-mutant NHL on EZH2 activity and portend the utility of EPZ-6438 as a potential treatment for these genetically defined cancers. Mol Cancer Ther; 13(4); 842–54. ©2014 AACR.
Data from Metronomic Docetaxel in PRINT Nanoparticles and EZH2 Silencing Have Synergistic Antitumor Effect in Ovarian Cancer
Authors: Gharpure Kshipra M. , Chu Kevin S. , Bowerman Charles J. , Miyake Takahito , Pradeep Sunila , Mangala Selanere L. , Han Hee-Dong , Rupaimoole Rajesha , Armaiz-Pena Guillermo N. , Rahhal Tojan B. , Wu Sherry Y. , Luft J. Christopher , Napier Mary E. , Lopez-Berestein Gabriel , DeSimone Joseph M. , Sood Anil K.
Published: March 2024

Abstract
The purpose of this study was to investigate the antitumor effects of a combination of metronomic doses of a novel delivery vehicle, PLGA-PRINT nanoparticles containing docetaxel, and antiangiogenic mEZH2 siRNA incorporated into chitosan nanoparticles. In vivo dose-finding studies and therapeutic experiments were conducted in well-established orthotopic mouse models of epithelial ovarian cancer. Antitumor effects were determined on the basis of reduction in mean tumor weight and number of metastatic tumor nodules in the animals. The tumor tissues from these in vivo studies were stained to evaluate the proliferation index (Ki67), apoptosis index (cleaved caspase 3), and microvessel density (CD31). The lowest dose of metronomic regimen (0.5 mg/kg) resulted in significant reduction in tumor growth. The combination of PLGA-PRINT-docetaxel and CH-mEZH2 siRNA showed significant antitumor effects in the HeyA8 and SKOV3ip1 tumor models (P < 0.05). Individual as well as combination therapies showed significant antiangiogenic, antiproliferative, and proapoptotic effects, and combination therapy had additive effects. Metronomic delivery of PLGA-PRINT-docetaxel combined with CH-mEZH2 siRNA has significant antitumor activity in preclinical models of ovarian cancer. Mol Cancer Ther; 13(7); 1750–7. ©2014 AACR.
Data from Blockade of mTOR Signaling via Rapamycin Combined with Immunotherapy Augments Antiglioma Cytotoxic and Memory T-Cell Functions
Authors: Mineharu Yohei , Kamran Neha , Lowenstein Pedro R. , Castro Maria G.
Published: March 2024

Abstract
The success of immunotherapeutic approaches targeting glioblastoma multiforme (GBM) demands a robust antiglioma T-cell cytotoxic and memory response. Recent evidence suggests that rapamycin regulates T-cell differentiation. Herein, we tested whether administration of rapamycin could enhance the efficacy of immunotherapy utilizing Fms-like tyrosine kinase 3 ligand (Ad-Flt3L) and thymidine kinase/ganciclovir (Ad-TK/GCV). Using the refractory rat RG2 glioma model, we demonstrate that administration of rapamycin with Ad-Flt3L + Ad-TK/GCV immunotherapy enhanced the cytotoxic activity of antitumor CD8+ T cells. Rats treated with rapamycin + Ad-Flt3L + Ad-TK/GCV exhibited massive reduction in the tumor volume and extended survival. Rapamycin administration also prolonged the survival of Ad-Flt3L + Ad-TK/GCV–treated GL26 tumor–bearing mice, associated with an increase in the frequency of tumor-specific and IFNγ+ CD8+ T cells. More importantly, rapamycin administration, even for a short interval, elicited a potent long-lasting central memory CD8+ T-cell response. The enhanced memory response translated to an increased frequency of tumor-specific CD8+ T cells within the tumor and IFNγ release, providing the mice with long-term survival advantage in response to tumor rechallenge. Our data, therefore, point to rapamycin as an attractive adjuvant to be used in combination with immunotherapy in a phase I clinical trial for GBM. Mol Cancer Ther; 13(12); 3024–36. ©2014 AACR.
Data from Targeting Multiple Key Signaling Pathways in Melanoma Using Leelamine
Authors: Gowda Raghavendra , Madhunapantula SubbaRao V. , Kuzu Omer F. , Sharma Arati , Robertson Gavin P.
Published: March 2024

Abstract
Melanoma is a highly drug-resistant cancer with resistance developing to agents targeting single proteins. To circumvent this problem, a new class of agent inhibiting multiple key pathways important in this disease is being developed to reduce the likelihood of developing resistant disease. The phosphoinositide 3-kinase (PI3K), mitogen-activated protein kinase (MAPK), and STAT3 pathways are constitutively activated in 50% to 70% of melanomas, promoting disease development. To identify a drug simultaneously targeting the PI3K, MAPK, and STAT3 cascades, a natural product library was screened to identify leelamine as a potential inhibitor. Leelamine was 4.5-fold more effective at inhibiting cultured melanoma cell survival than normal cells, with average IC50 values of 2 and 9.3 μmol/L, respectively. It inhibited cellular proliferation at a concentration of 2.5 μmol/L by 40% to 80% and longer exposure increased apoptosis 600%. Leelamine inhibited the growth of preexisting xenografted melanoma tumors by an average of 60% by targeting the PI3K, MAPK, and STAT3 pathways without affecting animal body weight or blood markers of major organ function. The mechanism of action of leelamine is mediated by disruption of cholesterol transport, causing decreased cellular proliferation and consequently leading to increased tumor cell apoptosis as well as decreased tumor vascularization. Thus, a unique agent and novel mechanism of action has been identified for the treatment of melanoma that acts by inhibiting the activity of three major signaling pathways regulating the development of this disease. Mol Cancer Ther; 13(7); 1679–89. ©2014 AACR.