bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from A Simple Three-dimensional Hydrogel Platform Enables Ex Vivo Cell Culture of Patient and PDX Tumors for Assaying Their Response to Clinically Relevant Therapies
Authors: Hribar Kolin C. , Wheeler Christopher J. , Bazarov Alexey , Varshneya Kunal , Yamada Ryosuke , Buckley Padraig , Patil Chirag G.
Published: March 2024

Abstract
A cell culture platform that enables ex vivo tissue growth from patients or patient-derived xenograft (PDX) models and assesses sensitivity to approved therapies (e.g., temozolomide) in a clinically relevant time frame would be very useful in translational research and personalized medicine. Here, we present a novel three-dimensional (3D) ECM hydrogel system, VersaGel, for assaying ex vivo growth and therapeutic response with standard image microscopy. Specifically, multicellular spheroids deriving from either 5 patients with glioblastoma (GBM) or a renal cell carcinoma (RCC) PDX model were incorporated into VersaGel and treated with temozolomide and several other therapies, guided by the most recent advances in GBM treatment. RCC ex vivo tissue displayed invasive phenotypes in conditioned media. For the GBM patient tumor testing, all five clinical responses were predicted by the results of our 3D-temozolomide assay. In contrast, the MTT assay found no response to temozolomide regardless of the clinical outcome, and moreover, basement membrane extract failed to predict the 2 patient responders. Finally, 1 patient was tested with repurposed drugs currently being administered in GBM clinical trials. Interestingly, IC50s were lower than Cmax for crizotinib and chloroquine, but higher for sorafenib. In conclusion, a novel hydrogel platform, VersaGel, enables ex vivo tumor growth of patient and PDX tissue and offers insight into patient response to clinically relevant therapies. We propose a novel 3D hydrogel platform, VersaGel, to grow ex vivo tissue (patient and PDX) and assay therapeutic response using time-course image analysis.
Data from Small Molecule–Mediated Activation of RAS Elicits Biphasic Modulation of Phospho-ERK Levels that Are Regulated through Negative Feedback on SOS1
Authors: Howes Jennifer E. , Akan Denis T. , Burns Michael C. , Rossanese Olivia W. , Waterson Alex G. , Fesik Stephen W.
Published: March 2024

Abstract
Oncogenic mutation of RAS results in aberrant cellular signaling and is responsible for more than 30% of all human tumors. Therefore, pharmacologic modulation of RAS has attracted great interest as a therapeutic strategy. Our laboratory has recently discovered small molecules that activate Son of Sevenless (SOS)–catalyzed nucleotide exchange on RAS and inhibit downstream signaling. Here, we describe how pharmacologically targeting SOS1 induced biphasic modulation of RAS-GTP and ERK phosphorylation levels, which we observed in a variety of cell lines expressing different RAS-mutant isoforms. We show that compound treatment caused an increase in phosphorylation at ERK consensus motifs on SOS1 that was not observed with the expression of a non-phosphorylatable S1178A SOS1 mutant or after pretreatment with an ERK inhibitor. Phosphorylation at S1178 on SOS1 is known to inhibit the association between SOS1 and GRB2 and disrupt SOS1 membrane localization. Consistent with this, we show that wild-type SOS1 and GRB2 dissociated in a time-dependent fashion in response to compound treatment, and conversely, this interaction was enhanced with the expression of an S1178A SOS1 mutant. Furthermore, in cells expressing either S1178A SOS1 or a constitutively membrane-bound CAAX box tagged SOS1 mutant, we observed elevated RAS-GTP levels over time in response to compound, as compared with the biphasic changes in RAS-GTP exhibited in cells expressing wild-type SOS1. These results suggest that small molecule targeting of SOS1 can elicit a biphasic modulation of RAS-GTP and phospho-ERK levels through negative feedback on SOS1 that regulates the interaction between SOS1 and GRB2. Mol Cancer Ther; 17(5); 1051–60. ©2018 AACR.
Data from JQ1 Induces DNA Damage and Apoptosis, and Inhibits Tumor Growth in a Patient-Derived Xenograft Model of Cholangiocarcinoma
Authors: Garcia Patrick L. , Miller Aubrey L. , Gamblin Tracy L. , Council Leona N. , Christein John D. , Arnoletti J. Pablo , Heslin Marty J. , Reddy Sushanth , Richardson Joseph H. , Cui Xiangqin , van Waardenburg Robert C.A.M. , Bradner James E. , Yang Eddy S. , Yoon Karina J.
Published: March 2024

Abstract
Cholangiocarcinoma (CCA) is a fatal disease with a 5-year survival of <30%. For a majority of patients, chemotherapy is the only therapeutic option, and virtually all patients relapse. Gemcitabine is the first-line agent for treatment of CCA. Patients treated with gemcitabine monotherapy survive ∼8 months. Combining this agent with cisplatin increases survival by ∼3 months, but neither regimen produces durable remissions. The molecular etiology of this disease is poorly understood. To facilitate molecular characterization and development of effective therapies for CCA, we established a panel of patient-derived xenograft (PDX) models of CCA. We used two of these models to investigate the antitumor efficacy and mechanism of action of the bromodomain inhibitor JQ1, an agent that has not been evaluated for the treatment of CCA. The data show that JQ1 suppressed the growth of the CCA PDX model CCA2 and demonstrate that growth suppression was concomitant with inhibition of c-Myc protein expression. A second model (CCA1) was JQ1-insensitive, with tumor progression and c-Myc expression unaffected by exposure to this agent. Also selective to CCA2 tumors, JQ1 induced DNA damage and apoptosis and downregulated multiple c-Myc transcriptional targets that regulate cell-cycle progression and DNA repair. These findings suggest that c-Myc inhibition and several of its transcriptional targets may contribute to the mechanism of action of JQ1 in this tumor type. We conclude that BET inhibitors such as JQ1 warrant further investigation for the treatment of CCA. Mol Cancer Ther; 17(1); 107–18. ©2017 AACR.
Data from Scavenger Receptor Type B1 and Lipoprotein Nanoparticle Inhibit Myeloid-Derived Suppressor Cells
Authors: Plebanek Michael P. , Bhaumik Debayan , Bryce Paul J. , Thaxton C. Shad
Published: March 2024

Abstract
Myeloid-derived suppressor cells (MDSC) are innate immune cells that potently inhibit T cells. In cancer, novel therapies aimed to activate T cells can be rendered ineffective due to the activity of MDSCs. Thus, targeted inhibition of MDSCs may greatly enhance T-cell–mediated antitumor immunity, but mechanisms remain obscure. Here we show, for the first time, that scavenger receptor type B-1 (SCARB1), a high-affinity receptor for spherical high-density lipoprotein (HDL), is expressed by MDSCs. Furthermore, we demonstrate that SCARB1 is specifically targeted by synthetic high-density lipoprotein-like nanoparticles (HDL NP), which reduce MDSC activity. Using in vitro T-cell proliferation assays, data show that HDL NPs specifically bind SCARB1 to inhibit MDSC activity. In murine cancer models, HDL NP treatment significantly reduces tumor growth, metastatic tumor burden, and increases survival due to enhanced adaptive immunity. Flow cytometry and IHC demonstrate that HDL NP–mediated suppression of MDSCs increased CD8+ T cells and reduced Treg cells in the metastatic tumor microenvironment. Using transgenic mice lacking SCARB1, in vivo data clearly show that the HDL NPs specifically target this receptor for suppressing MDSCs. Ultimately, our data provide a new mechanism and targeted therapy, HDL NPs, to modulate a critical innate immune cell checkpoint to enhance the immune response to cancer. Mol Cancer Ther; 17(3); 686–97. ©2017 AACR.
Data from ST8SIA1 Regulates Tumor Growth and Metastasis in TNBC by Activating the FAK–AKT–mTOR Signaling Pathway
Authors: Nguyen Khoa , Yan Yuanqing , Yuan Bin , Dasgupta Abhishek , Sun Jeffrey , Mu Hong , Do Kim-Anh , Ueno Naoto T. , Andreeff Michael , Battula V. Lokesh
Published: March 2024

Abstract
Breast cancer stem-like cells (BCSC) are implicated in cancer recurrence and metastasis of triple-negative breast cancer (TNBC). We have recently discovered that ganglioside GD2 expression defines BCSCs and that ST8SIA1 regulates GD2 expression and BCSC function. In this report, we show that ST8SIA1 is highly expressed in primary TNBC; its expression is positively correlated with the expression of several BCSC-associated genes such as BCL11A, FOXC1, CXCR4, PDGFRβ, SOX2, and mutations in p53. CRISPR knockout of ST8SIA1 completely inhibited BCSC functions, including in vitro tumorigenesis and mammosphere formation. Mechanistic studies discovered activation of the FAK–AKT–mTOR signaling pathway in GD2+ BCSCs, and its tight regulation by ST8SIA1. Finally, knockout of ST8SIA1 completely blocked in vivo tumor growth and metastasis by TNBC cells. In summary, these data demonstrate the mechanism by which ST8SIA1 regulates tumor growth and metastasis in TNBC and identifies it as a novel therapeutic target.
Data from EGF Receptor and mTORC1 Are Novel Therapeutic Targets in Nonseminomatous Germ Cell Tumors
Authors: Chen Kenneth S. , Fustino Nicholas J. , Shukla Abhay A. , Stroup Emily K. , Budhipramono Albert , Ateek Christina , Stuart Sarai H. , Yamaguchi Kiyoshi , Kapur Payal , Frazier A. Lindsay , Lum Lawrence , Looijenga Leendert H.J. , Laetsch Theodore W. , Rakheja Dinesh , Amatruda James F.
Published: March 2024

Abstract
Germ cell tumors (GCT) are malignant tumors that arise from pluripotent embryonic germ cells and occur in children and young adults. GCTs are treated with cisplatin-based regimens which, while overall effective, fail to cure all patients and cause significant adverse late effects. The seminoma and nonseminoma forms of GCT exhibit distinct differentiation states, clinical behavior, and response to treatment; however, the molecular mechanisms of GCT differentiation are not fully understood. We tested whether the activity of the mTORC1 and MAPK pathways were differentially active in the two classes of GCT. Here we show that nonseminomatous germ cell tumors (NSGCT, including embryonal carcinoma, yolk sac tumor, and choriocarcinoma) from both children and adults display activation of the mTORC1 pathway, while seminomas do not. In seminomas, high levels of REDD1 may negatively regulate mTORC1 activity. In NSGCTs, on the other hand, EGF and FGF2 ligands can stimulate mTORC1 and MAPK signaling, and members of the EGF and FGF receptor families are more highly expressed. Finally, proliferation of NSGCT cells in vitro and in vivo is significantly inhibited by combined treatment with the clinically available agents erlotinib and rapamycin, which target EGFR and mTORC1 signaling, respectively. These results provide an understanding of the signaling network that drives GCT growth and a rationale for therapeutic targeting of GCTs with agents that antagonize the EGFR and mTORC1 pathways. Mol Cancer Ther; 17(5); 1079–89. ©2018 AACR.
Data from The Unfolded Protein Response: A Novel Therapeutic Target for Poor Prognostic BRAF Mutant Colorectal Cancer
Authors: Forsythe Nicholas , Refaat Alaa , Javadi Arman , Khawaja Hajrah , Weir Jessica-Anne , Emam Heba , Allen Wendy L. , Burkamp Frank , Popovici Vlad , Jithesh Puthen V. , Isella Claudio , Labonte Melissa J. , Mills Ian G. , Johnston Patrick G. , Van Schaeybroeck Sandra
Published: March 2024

Abstract
BRAFV600E mutations occur in ∼10% of colorectal cancer cases, are associated with poor survival, and have limited responses to BRAF/MEK inhibition with or without EGFR inhibition. There is an unmet need to understand the biology of poor prognostic BRAFMT colorectal cancer. We have used differential gene expression and pathway analyses of untreated stage II and stage III BRAFMT (discovery set: n = 31; validation set: n = 26) colorectal cancer, and an siRNA screen to characterize the biology underpinning the BRAFMT subgroup with poorest outcome. These analyses identified the unfolded protein response (UPR) as a novel and druggable pathway associated with the BRAFMT colorectal cancer subgroup with poorest outcome. We also found that oncogenic BRAF drives endoplasmic reticulum (ER) stress and UPR pathway activation through MEK/ERK. Furthermore, inhibition of GRP78, the master regulator of the UPR, using siRNA or small molecule inhibition, resulted in acute ER stress and apoptosis, in particular in BRAFMT colorectal cancer cells. In addition, dual targeting of protein degradation using combined Carfilzomib (proteasome inhibitor) and ACY-1215 (HDAC6-selective inhibitor) treatment resulted in marked accumulation of protein aggregates, acute ER stress, apoptosis, and therapeutic efficacy in BRAFMT in vitro and xenograft models. Mechanistically, we found that the apoptosis following combined Carfilzomib/ACY-1215 treatment is mediated through increased CHOP expression. Taken together, our findings indicate that oncogenic BRAF induces chronic ER stress and that inducers of acute ER stress could be a novel treatment strategy for poor prognostic BRAFMT colorectal cancer. Mol Cancer Ther; 17(6); 1280–90. ©2018 AACR.
Data from Ceritinib Enhances the Efficacy of Trametinib in BRAF/NRAS-Wild-Type Melanoma Cell Lines
Authors: Verduzco Daniel , Kuenzi Brent M. , Kinose Fumi , Sondak Vernon K. , Eroglu Zeynep , Rix Uwe , Smalley Keiran S.M.
Published: March 2024

Abstract
Targeted therapy options are currently lacking for the heterogeneous population of patients whose melanomas lack BRAF or NRAS mutations (∼35% of cases). We undertook a chemical biology screen to identify potential novel drug targets for this understudied group of tumors. Screening a panel of 8 BRAF/NRAS-WT melanoma cell lines against 240 targeted drugs identified ceritinib and trametinib as potential hits with single-agent activity. Ceritinib enhanced the efficacy of trametinib across the majority of the BRAF/NRAS-WT cell lines, and the combination showed increased cytotoxicity in both three-dimensional spheroid culture and long-term colony formation experiments. Coadministration of ceritinib and trametinib led to robust inhibition of tumor growth in an in vivo xenograft BRAF/NRAS-WT melanoma model; this was not due to ALK inhibition by ceritinib. Mechanistic studies showed the ceritinib–trametinib combination to increase suppression of MAPK and TORC1 signaling. Similar results were seen when BRAF/NRAS-WT melanoma cells were treated with a combination of trametinib and the TORC1/2 inhibitor INK128. We next used mass spectrometry–based chemical proteomics and identified known and new ceritinib targets, such as IGF1R and ACK1, respectively. Validation studies suggested that ceritinib could suppress mTORC1 signaling in the presence of trametinib through inhibition of IGF1R and/or ACK1 in a cell line–dependent manner. Together, our studies demonstrated that combining a specific inhibitor (trametinib) with a more broadly targeted agent (ceritinib) has efficacy against tumors with heterogeneous mutational profiles. Mol Cancer Ther; 17(1); 73–83. ©2017 AACR.
Data from Next-Generation Sequencing of Tissue and Circulating Tumor DNA: The UC San Diego Moores Center for Personalized Cancer Therapy Experience with Breast Malignancies
Authors: Shatsky Rebecca , Parker Barbara A. , Bui Nam Q. , Helsten Teresa , Schwab Richard B. , Boles Sarah G , Kurzrock Razelle
Published: March 2024

Abstract
Clinical-grade next-generation sequencing (NGS) of tissue- and blood-derived circulating tumor DNA (ctDNA) allows assessment of multiple genomic alterations in patients with cancer. We analyzed ctDNA (54–70 genes) in 62 patients with advanced breast cancer (median = five prior therapies); 38 also had tissue NGS (236–315 genes). Overall, 42 of 62 patients (68%) had detectable (characterized) ctDNA alterations (variants of unknown significance excluded), and 37 of 38 (97%) had tissue alterations. The median (range) number of characterized alterations in ctDNA was 1 (0–7), and in tissue, 4 (0–17). The most common alterations in ctDNA were in TP53 (37% of patients) and PIK3CA (23%), and for tissue, TP53 (37%) and PIK3CA (24%); EGFR amplification was seen in ctDNA (11%), but not in tissue. Concordance between ctDNA and tissue appeared higher if <6 months separated the sample acquisition, although small sample size precluded statistical validation. Overall, 32 of 67 tissue alterations (48%) were also detected in ctDNA; 35 of 72 ctDNA alterations (48%) were also in tissue. Excluding estrogen receptor and ERBB2, 41 of 62 patients (66%) had potentially actionable alterations in ctDNA, and 36 of 38 (95%), in tissue (with potential actionability based on either preclinical or clinical evidence). If ≥1 genomic alteration had ctDNA ≥5%, survival was shorter than if ctDNA was <5% (median, 6.7 vs. 17.9 months; P = 0.01). In conclusion, tissue and ctDNA NGS reveal potentially actionable alterations in most patients. The genomic results of ctDNA and tissue NGS overlap, but there are differences, perhaps reflecting temporal spacing and tumor heterogeneity. ctDNA quantification also provides prognostic information.
Data from MicroRNA-203 Inhibits Long Noncoding RNA HOTAIR and Regulates Tumorigenesis through Epithelial-to-mesenchymal Transition Pathway in Renal Cell Carcinoma
Authors: Dasgupta Pritha , Kulkarni Priyanka , Majid Shahana , Shahryari Varahram , Hashimoto Yutaka , Bhat Nadeem S. , Shiina Marisa , Deng Guoren , Saini Sharanjot , Tabatabai Z. Laura , Yamamura Soichiro , Tanaka Yuichiro , Dahiya Rajvir
Published: March 2024

Abstract
This study aims to investigate the role of miR-203–HOTAIR interaction in the suppression of renal cell carcinoma (RCC). We employed series of in vitro assays such as proliferation, invasion, migration, and colony formation along with in vivo tumor xenograft model. Profiling of miR-203 and HOTAIR expression revealed that miR-203 was significantly underexpressed, whereas HOTAIR was overexpressed in RCC cell lines and clinical specimens compared with normal cell line and tissue. Both miR-203 and HOTAIR expression significantly distinguished malignant from normal tissues and significantly correlated with clinicopathologic characteristics of patients. Overexpression of miR-203 significantly inhibited proliferation, migration, and invasion with an induction of apoptosis and cell-cycle arrest. However, HOTAIR suppression resulted in the similar functional effects in the same RCC cell lines. In silico, RNA-22 algorithm showed a binding site for miR-203 in HOTAIR. We observed a direct interaction between miR-203 and HOTAIR by RNA-immunoprecipitation (RIP) and luciferase reporter assays. We show that miR-203–HOTAIR interaction resulted in the inhibition of epithelial-to-mesenchymal transition (EMT) and metastatic genes as indicated by induction of key metastasis-suppressing proteins E-cadherin, claudin (epithelial markers), and PTEN along with induction of tumor suppressor genes p21 and p27. A significant decrease in vimentin (mesenchymal marker), KLF4, and Nanog (stemness markers) was also observed. This is the first report demonstrating miR-203–mediated regulation of HOTAIR induces tumor suppressor effects in RCC by regulating EMT and metastatic pathway genes. Thus, the study suggests that therapeutic regulation of HOTAIR by miR-203 overexpression may provide an opportunity to regulate RCC growth and metastasis. Mol Cancer Ther; 17(5); 1061–9. ©2018 AACR.
Data from Evaluating the Mechanism and Therapeutic Potential of PTC-028, a Novel Inhibitor of BMI-1 Function in Ovarian Cancer
Authors: Dey Anindya , Xiong Xunhao , Crim Aleia , Dwivedi Shailendra Kumar Dhar , Mustafi Soumyajit Banerjee , Mukherjee Priyabrata , Cao Liangxian , Sydorenko Nadiya , Baiazitov Ramil , Moon Young-Choon , Dumble Melissa , Davis Thomas , Bhattacharya Resham
Published: March 2024

Abstract
BMI-1, also known as a stem cell factor, is frequently upregulated in several malignancies. Elevated expression of BMI-1 correlates with poor prognosis and is therefore considered a viable therapeutic target in a number of malignancies including ovarian cancer. Realizing the immense pathologic significance of BMI-1, small-molecule inhibitors against BMI-1 are recently being developed. In this study, we functionally characterize PTC-028, an orally bioavailable compound that decreases BMI-1 levels by posttranslational modification. We report that PTC-028 treatment selectively inhibits cancer cells in clonal growth and viability assays, whereas normal cells remain unaffected. Mechanistically, hyperphosphorylation-mediated depletion of cellular BMI-1 by PTC-028 coupled with a concurrent temporal decrease in ATP and a compromised mitochondrial redox balance potentiates caspase-dependent apoptosis. In vivo, orally administered PTC-028, as a single agent, exhibits significant antitumor activity comparable with the standard cisplatin/paclitaxel therapy in an orthotopic mouse model of ovarian cancer. Thus, PTC-028 has the potential to be used as an effective therapeutic agent in patients with epithelial ovarian cancer, where treatment options are limited. Mol Cancer Ther; 17(1); 39–49. ©2017 AACR.
Data from Analysis of Tissue and Circulating Tumor DNA by Next-Generation Sequencing of Hepatocellular Carcinoma: Implications for Targeted Therapeutics
Authors: Ikeda Sadakatsu , Lim Jordan S. , Kurzrock Razelle
Published: March 2024

Abstract
Hepatocellular carcinoma (HCC) has limited treatment options. Molecular analysis of its mutational landscape may enable the identification of novel therapies. However, biopsy is not routinely performed in HCC. The utility of analyzing cell-free circulating tumor DNA (ctDNA) by next-generation sequencing (NGS) is not established. We performed 32 ctDNA NGS analyses on 26 patients; 10 of these patients had tissue NGS (236 to 626 genes). ctDNA was evaluated using an assay that detects single nucleotide variants, amplifications, fusions, and specific insertion/deletion alterations in 54 to 70 genes. The ctDNA demonstrated that 23 of 26 patients (88.5%) had ≥1 characterized alteration, and all these individuals had ≥1 potentially actionable alteration. The most frequently mutated gene was TP53 (16 of 26 patients, 61.5%). There were 47 unique characterized molecular alterations among 18 total gene alterations [variants of unknown significance (VUS) excluded)]. ctDNA and tissue NGS frequently showed different profiles, perhaps due to length of time between tissue and blood samples [median = 370 days (range, 29 to 876 days)]. Serial ctDNA evaluation in an illustrative patient treated with capecitabine demonstrated emergence of a new TP53 alteration after progression. In conclusion, ctDNA profiling is feasible in advanced HCC, and serial assessment using ctDNA NGS can reveal genomic changes with time. NGS of ctDNA provides a minimally invasive alternative for identifying potentially actionable gene alterations and potential molecular targeted therapies. Dynamic changes in molecular portfolio associated with therapeutic pressure in difficult-to-biopsy patients can be observed. Mol Cancer Ther; 17(5); 1114–22. ©2018 AACR.
Data from Combined MEK and BCL-2/XL Inhibition Is Effective in High-Grade Serous Ovarian Cancer Patient–Derived Xenograft Models and BIM Levels Are Predictive of Responsiveness
Authors: Iavarone Claudia , Zervantonakis Ioannis K. , Selfors Laura M. , Palakurthi Sangeetha , Liu Joyce F. , Drapkin Ronny , Matulonis Ursula A. , Hallberg Dorothy , Velculescu Victor E. , Leverson Joel D. , Sampath Deepak , Mills Gordon B. , Brugge Joan S.
Published: March 2024

Abstract
Most patients with late-stage high-grade serous ovarian cancer (HGSOC) initially respond to chemotherapy but inevitably relapse and develop resistance, highlighting the need for novel therapies to improve patient outcomes. The MEK/ERK pathway is activated in a large subset of HGSOC, making it an attractive therapeutic target. Here, we systematically evaluated the extent of MEK/ERK pathway activation and efficacy of pathway inhibition in a large panel of well-annotated HGSOC patient–derived xenograft models. The vast majority of models were nonresponsive to the MEK inhibitor cobimetinib (GDC-0973) despite effective pathway inhibition. Proteomic analyses of adaptive responses to GDC-0973 revealed that GDC-0973 upregulated the proapoptotic protein BIM, thus priming the cells for apoptosis regulated by BCL2-family proteins. Indeed, combination of both MEK inhibitor and dual BCL-2/XL inhibitor (ABT-263) significantly reduced cell number, increased cell death, and displayed synergy in vitro in most models. In vivo, GDC-0973 and ABT-263 combination was well tolerated and resulted in greater tumor growth inhibition than single agents. Detailed proteomic and correlation analyses identified two subsets of responsive models—those with high BIM at baseline that was increased with MEK inhibition and those with low basal BIM and high pERK levels. Models with low BIM and low pERK were nonresponsive. Our findings demonstrate that combined MEK and BCL-2/XL inhibition has therapeutic activity in HGSOC models and provide a mechanistic rationale for the clinical evaluation of this drug combination as well as the assessment of the extent to which BIM and/or pERK levels predict drug combination effectiveness in chemoresistant HGSOC.
Data from Targeting MEK in a Translational Model of Histiocytic Sarcoma
Authors: Takada Marilia , Hix Jeremy M.L. , Corner Sarah , Schall Peter Z. , Kiupel Matti , Yuzbasiyan-Gurkan Vilma
Published: March 2024

Abstract
Histiocytic sarcoma in humans is an aggressive orphan disease with a poor prognosis as treatment options are limited. Dogs are the only species that spontaneously develops histiocytic sarcoma with an appreciable frequency, and may have value as a translational model system. In the current study, high-throughput drug screening utilizing histiocytic sarcoma cells isolated from canine neoplasms identified these cells as particularly sensitive to a MEK inhibitor, trametinib. One of the canine cell lines carries a mutation in PTPN11 (E76K), and another one in KRAS (Q61H), which are associated with the activation of oncogenic MAPK signaling. Both mutations were previously reported in human histiocytic sarcoma. Trametinib inhibited sensitive cell lines by promoting cell apoptosis, indicated by a significant increase in caspase 3/7. Furthermore, in vitro findings were successfully recapitulated in an intrasplenic orthotopic xenograft mouse model, which represents a disseminated aggressive form of histiocytic sarcoma. Mice with histiocytic sarcoma xenograft neoplasms that were treated with trametinib had significantly longer survival times. Target engagement was validated as activity of ERK, downstream of MEK, was significantly downregulated in neoplasms of treated mice. Additionally, trametinib was found in plasma and neoplastic tissues within projected therapeutic levels. These findings demonstrate that in dogs, histiocytic sarcoma may be associated with a dysfunctional MAPK pathway, at least in some cases, and may be effectively targeted through MEK inhibition. Clinical trials to test safety and efficacy of trametinib in dogs with histiocytic sarcoma are warranted, and may provide valuable translational information to similar diseases in humans. Mol Cancer Ther; 17(11); 2439–50. ©2018 AACR.
Data from High Proliferation Rate and a Compromised Spindle Assembly Checkpoint Confers Sensitivity to the MPS1 Inhibitor BOS172722 in Triple-Negative Breast Cancers
Authors: Anderhub Simon J. , Mak Grace Wing-Yan , Gurden Mark D. , Faisal Amir , Drosopoulos Konstantinos , Walsh Katie , Woodward Hannah L. , Innocenti Paolo , Westwood Isaac M. , Naud Sébastien , Hayes Angela , Theofani Efthymia , Filosto Simone , Saville Harry , Burke Rosemary , van Montfort Rob L.M. , Raynaud Florence I. , Blagg Julian , Hoelder Swen , Eccles Suzanne A. , Linardopoulos Spiros
Published: March 2024

Abstract
BOS172722 (CCT289346) is a highly potent, selective, and orally bioavailable inhibitor of spindle assembly checkpoint kinase MPS1. BOS172722 treatment alone induces significant sensitization to death, particularly in highly proliferative triple-negative breast cancer (TNBC) cell lines with compromised spindle assembly checkpoint activity. BOS172722 synergizes with paclitaxel to induce gross chromosomal segregation defects caused by MPS1 inhibitor–mediated abrogation of the mitotic delay induced by paclitaxel treatment. In in vivo pharmacodynamic experiments, BOS172722 potently inhibits the spindle assembly checkpoint induced by paclitaxel in human tumor xenograft models of TNBC, as measured by inhibition of the phosphorylation of histone H3 and the phosphorylation of the MPS1 substrate, KNL1. This mechanistic synergy results in significant in vivo efficacy, with robust tumor regressions observed for the combination of BOS172722 and paclitaxel versus either agent alone in long-term efficacy studies in multiple human tumor xenograft TNBC models, including a patient-derived xenograft and a systemic metastasis model. The current target indication for BOS172722 is TNBC, based on their high sensitivity to MPS1 inhibition, the well-defined clinical patient population with high unmet need, and the synergy observed with paclitaxel.
Data from ABT-165, a Dual Variable Domain Immunoglobulin (DVD-Ig) Targeting DLL4 and VEGF, Demonstrates Superior Efficacy and Favorable Safety Profiles in Preclinical Models
Authors: Li Yingchun , Hickson Jonathan A. , Ambrosi Dominic J. , Haasch Deanna L. , Foster-Duke Kelly D. , Eaton Lucia J. , DiGiammarino Enrico L. , Panchal Sanjay C. , Jiang Fang , Mudd Sarah R. , Zhang Catherine , Akella Surekha S. , Gao Wenqing , Ralston Sherry L. , Naumovski Louie , Gu Jijie , Morgan-Lappe Susan E.
Published: March 2024

Abstract
Antiangiogenic therapy is a clinically validated modality in cancer treatment. To date, all approved antiangiogenic drugs primarily inhibit the VEGF pathway. Delta-like ligand 4 (DLL4) has been identified as a potential drug target in VEGF-independent angiogenesis and tumor-initiating cell (TIC) survival. A dual-specific biologic targeting both VEGF and DLL4 could be an attractive strategy to improve the effectiveness of anti-VEGF therapy. ABT-165 was uniquely engineered using a proprietary dual-variable domain immunoglobulin (DVD-Ig) technology based on its ability to bind and inhibit both DLL4 and VEGF. In vivo, ABT-165 induced significant tumor growth inhibition compared with either parental antibody treatment alone, due, in part, to the disruption of functional tumor vasculature. In combination with chemotherapy agents, ABT-165 also induced greater antitumor response and outperformed anti-VEGF treatment. ABT-165 displayed nonlinear pharmacokinetic profiles in cynomolgus monkeys, with an apparent terminal half-life > 5 days at a target saturation dose. In a GLP monkey toxicity study, ABT-165 was well-tolerated at doses up to 200 mg/kg with non-adverse treatment–related histopathology findings limited to the liver and thymus. In summary, ABT-165 represents a novel antiangiogenic strategy that potently inhibits both DLL4 and VEGF, demonstrating favorable in vivo efficacy, pharmacokinetic, and safety profiles in preclinical models. Given these preclinical attributes, ABT-165 has progressed to a phase I study. Mol Cancer Ther; 17(5); 1039–50. ©2018 AACR.
Data from Acquired Resistance to FGFR Inhibitor in Diffuse-Type Gastric Cancer through an AKT-Independent PKC-Mediated Phosphorylation of GSK3β
Authors: Lau Wen Min , Teng Eileen , Huang Kie Kyon , Tan Jin Wei , Das Kakoli , Zang Zhijiang , Chia Tania , Teh Ming , Kono Koji , Yong Wei Peng , Shabbir Asim , Tay Amy , Phua Niam Sin , Tan Patrick , Chan Shing Leng , So Jimmy Bok Yan
Published: March 2024

Abstract
Preclinical models of diffuse-type gastric cancer (DGC) that reliably predict clinical activity of novel compounds are lacking. To overcome the problem of poor tumor cellularity in DGC, we used cells from malignant ascites to establish DGC patient-derived xenograft (PDX) models that recapitulate the primary cancer. Cells in PDX model GAGA6 with FGFR2 amplification were sensitive to AZD4547, a potent FGFR inhibitor that is being clinically evaluated for FGFR-aberrant cancer types. Intermittent in vivo treatment of GAGA6 tumors with AZD4547 gave rise to PDX tumors with acquired resistance to AZD4547, GAGA6-R. Surprisingly, there were no mutations in the FGFR2 gene in GAGA6-R, negating gatekeeper mutations as a mechanism of drug resistance. Phosphorylation of FGFR2 and downstream signaling molecules AKT/PKB and MAPK/ERK remained inhibited by AZD4547. Further analysis of signaling pathways identified AKT-independent phosphorylation and inhibition of GSK3β as a mechanism of drug resistance in GAGA6-R cells. Treatment of GAGA6-R cells with protein kinase C (PKC) inhibitor H7 in combination with AZD4547 led to dephosphorylation and activation of GSK3β with concomitant downregulation of MCL-1 and BCL-XL. Combined treatment with AZD4547 and H7 in vitro synergistically enhanced cell death in GAGA6-R but not GAGA6 cells. Furthermore, midostaurin, a multikinase inhibitor with PKC-inhibiting activity, in part reversed resistance of GAGA6-R tumor to AZD4547 in vivo. Our results suggest that upon challenge with FGFR inhibitors, FGFR2-amplified tumors that are highly dependent on FGFR2 signaling for survival rapidly develop resistance by switching to a PKC-mediated inhibition of GSK3β to gain a survival advantage. Mol Cancer Ther; 17(1); 232–42. ©2017 AACR.
Data from Nanobody Targeting of Epidermal Growth Factor Receptor (EGFR) Ectodomain Variants Overcomes Resistance to Therapeutic EGFR Antibodies
Authors: Tintelnot Joseph , Baum Natalie , Schultheiß Christoph , Braig Friederike , Trentmann Marie , Finter Johannes , Fumey William , Bannas Peter , Fehse Boris , Riecken Kristoffer , Schuetze Kerstin , Bokemeyer Carsten , Rösner Thies , Valerius Thomas , Peipp Matthias , Koch-Nolte Friedrich , Binder Mascha
Published: March 2024

Abstract
Epidermal growth factor receptor (EGFR) ectodomain variants mediating primary resistance or secondary treatment failure in cancer patients treated with cetuximab or panitumumab support the need for more resistance-preventive or personalized ways of targeting this essential pathway. Here, we tested the hypothesis that the EGFR nanobody 7D12 fused to an IgG1 Fc portion (7D12-hcAb) would overcome EGFR ectodomain–mediated resistance because it targets a very small binding epitope within domain III of EGFR. Indeed, we found that 7D12-hcAb bound and inhibited all tested cell lines expressing common resistance-mediating EGFR ectodomain variants. Moreover, we assessed receptor functionality and binding properties in synthetic mutants of the 7D12-hcAb epitope to model resistance to 7D12-hcAb. Because the 7D12-hcAb epitope almost completely overlaps with the EGF-binding site, only position R377 could be mutated without simultaneous loss of receptor functionality, suggesting a low risk of developing secondary resistance toward 7D12-hcAb. Our binding data indicated that if 7D12-hcAb resistance mutations occurred in position R377, which is located within the cetuximab and panitumumab epitope, cells expressing these receptor variants would retain sensitivity to these antibodies. However, 7D12-hcAb was equally ineffective as cetuximab in killing cells expressing the cetuximab/panitumumab-resistant aberrantly N-glycosylated EGFR R521K variant. Yet, this resistance could be overcome by introducing mutations into the Fc portion of 7D12-hcAb, which enhanced immune effector functions and thereby allowed killing of cells expressing this variant. Taken together, our data demonstrate a broad range of activity of 7D12-hcAb across cells expressing different EGFR variants involved in primary and secondary EGFR antibody resistance.
Data from LCL161, a SMAC-mimetic, Preferentially Radiosensitizes Human Papillomavirus–negative Head and Neck Squamous Cell Carcinoma
Authors: Yang Linlin , Kumar Bhavna , Shen Changxian , Zhao Songzhu , Blakaj Dukagjin , Li Tianyun , Romito Mitchell , Teknos Theodoros N. , Williams Terence M.
Published: March 2024

Abstract
Targeting inhibitor of apoptosis proteins (IAP) with second mitochondria-derived activator of caspase (SMAC) mimetics may promote cancer cell death. We tested whether cIAP1 predicts poor prognosis in head and neck squamous cell carcinoma (HNSCC) and whether a novel Smac-mimetic, LCL161, could radiosensitize human papillomavirus–positive (HPV+) and -negative (HPV−) HNSCC. The association of BIRC2 (encoding cIAP1) mRNA level with HPV status in HNSCC was analyzed using The Cancer Genome Atlas (TCGA) database. cIAP1 was assessed by IHC on an HNSCC tissue microarray (TMA, n = 84) followed by correlation analysis with HPV status and patient outcomes. Human cell culture and animal models of HNSCC were used to analyze the outcome and molecular characteristics following radiotherapy in combination with LCL161. cIAP1 expression is increased in HPV− compared with HPV+HNSCC tumors in the TCGA database. In our TMA, cIAP1 was overexpressed in HNSCC compared with normal tissues (P = 0.0003) and associated with a poor overall survival (P = 0.0402). cIAP1 levels were higher in HPV− than that in HPV+HNSCC tumors (P = 0.004) and patients with cIAP1+/HPV− HNSCC had the worst survival. LCL161 effectively radiosensitized HPV− HNSCC cells, which was accompanied with enhanced apoptosis, but not HPV+ HNSCC cells. Importantly, LCL161 in combination with radiotherapy led to dramatic tumor regression of HPV− HNSCC tumor xenografts, accompanied by cIAP1 degradation and apoptosis activation. These results reveal that cIAP1 is a prognostic and a potential therapeutic biomarker for HNSCC, and targeting cIAP1 with LCL161 preferentially radiosensitizes HPV− HNSCC, providing justification for clinical testing of LCL161 in combination with radiation for patients with HPV− HNSCC.
Data from Wedelolactone, an Anti-inflammatory Botanical, Interrupts c-Myc Oncogenic Signaling and Synergizes with Enzalutamide to Induce Apoptosis in Prostate Cancer Cells
Authors: Sarveswaran Sivalokanathan , Ghosh Ritisha , Parikh Rujul , Ghosh Jagadananda
Published: March 2024

Abstract
The c-Myc gene encodes an oncoprotein transcription factor that is frequently upregulated in almost all cancer types and is the subject of intense investigation for management of cancer because of its pleiotropic effects controlling a spectrum of cellular functions. However, due of its nonenzymatic nature, development of suitable strategies to block its protein–protein or protein–DNA interaction is challenging. Thus, c-Myc has been recognized as an elusive molecular target for cancer control, and various approaches are in development to inhibit c-Myc transcriptional activity. We observed that wedelolactone (WDL), an anti-inflammatory botanical compound, severely downregulates the expression of c-Myc mRNA in prostate cancer cells. Moreover, WDL dramatically decreases the protein level, nuclear accumulation, DNA-binding, and transcriptional activities of c-Myc. c-Myc is a transforming oncogene widely expressed in prostate cancer cells and is critical for maintaining their transformed phenotype. Interestingly, WDL was found to strongly affect the viability of Myc-activated prostate cancer cells and completely block their invasion as well as soft agar colony formation in vitro. WDL was also found to downregulate c-Myc in vivo in nude mice xenografts. Moreover, WDL synergizes with enzalutamide to decrease the viability of androgen-sensitive prostate cancer cells via induction of apoptosis. These findings reveal a novel anticancer mechanism of the natural compound WDL, and suggest that the oncogenic function of c-Myc in prostate cancer cells can be effectively downregulated by WDL for the development of a new therapeutic strategy against Myc-driven prostate cancer. Mol Cancer Ther; 15(11); 2791–801. ©2016 AACR.
Data from Targeting PARP-1 with Alpha-Particles Is Potently Cytotoxic to Human Neuroblastoma in Preclinical Models
Authors: Makvandi Mehran , Lee Hwan , Puentes Laura N. , Reilly Sean W. , Rathi Komal S. , Weng Chi-Chang , Chan Ho Sze , Hou Catherine , Raman Pichai , Martinez Daniel , Xu Kuiying , Carlin Sean D. , Greenberg Roger A. , Pawel Bruce R. , Mach Robert H. , Maris John M. , Pryma Daniel A.
Published: March 2024

Abstract
Alpha-emitters can be pharmacologically delivered for irradiation of single cancer cells, but cellular lethality could be further enhanced by targeting alpha-emitters directly to the nucleus. PARP-1 is a druggable protein in the nucleus that is overexpressed in neuroblastoma compared with normal tissues and is associated with decreased survival in high-risk patients. To exploit this, we have functionalized a PARP inhibitor (PARPi) with an alpha-emitter astatine-211. This approach offers enhanced cytotoxicity from conventional PARPis by not requiring enzymatic inhibition of PARP-1 to elicit DNA damage; instead, the alpha-particle directly induces multiple double-strand DNA breaks across the particle track. Here, we explored the efficacy of [211At]MM4 in multiple cancers and found neuroblastoma to be highly sensitive in vitro and in vivo. Furthermore, alpha-particles delivered to neuroblastoma show antitumor effects and durable responses in a neuroblastoma xenograft model, especially when administered in a fractionated regimen. This work provides the preclinical proof of concept for an alpha-emitting drug conjugate that directly targets cancer chromatin as a therapeutic approach for neuroblastoma and perhaps other cancers.
Data from Short- and Long-Term Effects of CDK4/6 Inhibition on Early-Stage Breast Cancer
Authors: Kietzman William B. , Graham Garrett T. , Ory Virginie , Sharif Ghada M. , Kushner Max H. , Gallanis Gregory T. , Kallakury Bhaskar , Wellstein Anton , Riegel Anna T.
Published: March 2024

Abstract
CDK4/6 inhibitors are used in the treatment of advanced estrogen receptor (ER)(+) breast cancer. Their efficacy in ER(−) and early-stage breast cancer is currently under investigation. Here, we show that palbociclib, a CDK4/6 inhibitor, can inhibit both progression of ductal carcinoma in situ (DCIS) and growth of invasive disease in both an ER(−) basal breast cancer model (MCFDCIS) and an ER(+) luminal model (MCF7 intraductal injection). In MCFDCIS cells, palbociclib repressed cell-cycle gene expression, inhibited proliferation, induced senescence, and normalized tumorspheres formed in Matrigel while the formation of acini by normal mammary epithelial cells (MCF10A) was not affected. Palbociclib treatment of mice with MCFDCIS tumors inhibited their malignant progression and reduced proliferation of invasive lesions. Transcriptomic analysis of the tumor and stromal cell compartments showed that cell cycle and senescence genes, and MUC16, an ovarian cancer biomarker gene, were repressed during treatment. Knockdown of MUC16 in MCFDCIS cells inhibited proliferation of invasive lesions but not progression of DCIS. After cessation of palbociclib treatment genes associated with differentiation, for example, P63, inflammation, IFNγ response, and antigen processing and presentation remained suppressed in the tumor and surrounding stroma. We conclude that palbociclib can prevent progression of DCIS and is antiproliferative in ER(−) invasive disease mediated in part via MUC16. Lasting effects of CDK4/6 inhibition after drug withdrawal on differentiation and the immune response could impact the approach to treatment of early-stage ER(−) breast cancer.
Data from SF2523: Dual PI3K/BRD4 Inhibitor Blocks Tumor Immunosuppression and Promotes Adaptive Immune Responses in Cancer
Authors: Joshi Shweta , Singh Alok R. , Liu Kevin X. , Pham Timothy V. , Zulcic Muamera , Skola Dylan , Chun Hyun Bae , Glass Christopher K. , Morales Guillermo A. , Garlich Joseph R. , Durden Donald L.
Published: March 2024

Abstract
Macrophages (MΘs) are key immune infiltrates in solid tumors and serve as major drivers behind tumor growth, immune suppression, and inhibition of adaptive immune responses in the tumor microenvironment (TME). Bromodomain and extraterminal (BET) protein, BRD4, which binds to acetylated lysine on histone tails, has recently been reported to promote gene transcription of proinflammatory cytokines but has rarely been explored for its role in IL4-driven MΘ transcriptional programming and MΘ-mediated immunosuppression in the TME. Herein, we report that BET bromodomain inhibitor, JQ1, blocks association of BRD4 with promoters of arginase and other IL4-driven MΘ genes, which promote immunosuppression in TME. Pharmacologic inhibition of BRD4 using JQ1 and/or PI3K using dual PI3K/BRD4 inhibitor SF2523 (previously reported by our group as a potent inhibitor to block tumor growth and metastasis in various cancer models) suppresses tumor growth in syngeneic and spontaneous murine cancer models; reduces infiltration of myeloid-derived suppressor cells; blocks polarization of immunosuppressive MΘs; restores CD8+ T-cell activity; and stimulates antitumor immune responses. Finally, our results suggest that BRD4 regulates the immunosuppressive myeloid TME, and BET inhibitors and dual PI3K/BRD4 inhibitors are therapeutic strategies for cancers driven by the MΘ-dependent immunosuppressive TME.
Data from Macrophage-Mediated Trogocytosis Leads to Death of Antibody-Opsonized Tumor Cells
Authors: Velmurugan Ramraj , Challa Dilip K. , Ram Sripad , Ober Raimund J. , Ward E. Sally
Published: March 2024

Abstract
Understanding the complex behavior of effector cells such as monocytes or macrophages in regulating cancerous growth is of central importance for cancer immunotherapy. Earlier studies using CD20-specific antibodies have demonstrated that the Fcγ receptor (FcγR)–mediated transfer of the targeted receptors from tumor cells to these effector cells through trogocytosis can enable escape from antibody therapy, leading to the viewpoint that this process is protumorigenic. In the current study, we demonstrate that persistent trogocytic attack results in the killing of HER2-overexpressing breast cancer cells. Further, antibody engineering to increase FcγR interactions enhances this tumoricidal activity. These studies extend the complex repertoire of activities of macrophages to trogocytic-mediated cell death of HER2-overexpressing target cells and have implications for the development of effective antibody-based therapies. Mol Cancer Ther; 15(8); 1879–89. ©2016 AACR.
Data from Antileukemia Effects of Notch-Mediated Inhibition of Oncogenic PLK1 in B-Cell Acute Lymphoblastic Leukemia
Authors: Kannan Sankaranarayanan , Aitken Marisa J.L. , Herbrich Shelley M. , Golfman Leonard S. , Hall Mandy G. , Mak Duncan H. , Burks Jared K. , Song Guangchun , Konopleva Marina , Mullighan Charles G. , Chandra Joya , Zweidler-McKay Patrick A.
Published: March 2024

Abstract
In B-cell acute lymphoblastic leukemia (B-ALL), activation of Notch signaling leads to cell-cycle arrest and apoptosis. We aimed to harness knowledge acquired by understanding a mechanism of Notch-induced cell death to elucidate a therapeutically viable target in B-ALL. To this end, we identified that Notch activation suppresses Polo-like kinase 1 (PLK1) in a B-ALL–specific manner. We identified that PLK1 is expressed in all subsets of B-ALL and is highest in Philadelphia-like (Ph-like) ALL, a high-risk subtype of disease. We biochemically delineated a mechanism of Notch-induced PLK1 downregulation that elucidated stark regulation of p53 in this setting. Our findings identified a novel posttranslational cascade initiated by Notch in which CHFR was activated via PARP1-mediated PARylation, resulting in ubiquitination and degradation of PLK1. This led to hypophosphorylation of MDM2Ser260, culminating in p53 stabilization and upregulation of BAX. shRNA knockdown or pharmacologic inhibition of PLK1 using BI2536 or BI6727 (volasertib) in B-ALL cell lines and patient samples led to p53 stabilization and cell death. These effects were seen in primary human B-ALL samples in vitro and in patient-derived xenograft models in vivo. These results highlight PLK1 as a viable therapeutic target in B-ALL. Efficacy of clinically relevant PLK1 inhibitors in B-ALL patient-derived xenograft mouse models suggests that use of these agents may be tailored as an additional therapeutic strategy in future clinical studies.