Bromodomain inhibition overcomes treatment resistance in distinct molecular subtypes of melanoma.

Therapy of BRAF-mutant melanoma with selective inhibitors of BRAF (BRAFi) and MEK (MEKi) represents a major clinical advance but acquired resistance to therapy has emerged as a key obstacle. To date, no clinical approaches successfully resensitize to BRAF/MEK inhibition. Here, we develop a therapeutic strategy for melanoma using bromosporine, a bromodomain inhibitor. Bromosporine (bromo) monotherapy produced significant anti-tumor effects against established melanoma cell lines and patient-derived xenografts (PDXs). Combinatorial therapy involving bromosporine and cobimetinib (bromo/cobi) showed synergistic anti-tumor effects in multiple BRAFi-resistant PDX models. The bromo/cobi combination was superior in vivo to standard BRAFi/MEKi therapy in the treatment-naive BRAF-mutant setting and to MEKi alone in the setting of immunotherapy-resistant NRAS- and NF1-mutant melanoma. RNA sequencing of xenografts treated with bromo/cobi revealed profound down-regulation of genes critical to cell division and mitotic progression. Bromo/cobi treatment resulted in marked DNA damage and cell-cycle arrest, resulting in induction of apoptosis. These studies introduce bromodomain inhibition, alone or combined with agents targeting the mitogen activated protein kinase pathway, as a rational therapeutic approach for melanoma refractory to standard targeted or immunotherapeutic approaches.

PHIP drives glioblastoma motility and invasion by regulating the focal adhesion complex.

The invasive behavior of glioblastoma is essential to its aggressive potential. Here, we show that pleckstrin homology domain interacting protein (PHIP), acting through effects on the force transduction layer of the focal adhesion complex, drives glioblastoma motility and invasion. Immunofluorescence analysis localized PHIP to the leading edge of glioblastoma cells, together with several focal adhesion proteins: vinculin (VCL), talin 1 (TLN1), integrin beta 1 (ITGB1), as well as phosphorylated forms of paxillin (pPXN) and focal adhesion kinase (pFAK). Confocal microscopy specifically localized PHIP to the force transduction layer, together with TLN1 and VCL. Immunoprecipitation revealed a physical interaction between PHIP and VCL. Targeted suppression of PHIP resulted in significant down-regulation of these focal adhesion proteins, along with zyxin (ZYX), and produced profoundly disorganized stress fibers. Live-cell imaging of glioblastoma cells overexpressing a ZYX-GFP construct demonstrated a role for PHIP in regulating focal adhesion dynamics. PHIP silencing significantly suppressed the migratory and invasive capacity of glioblastoma cells, partially restored following TLN1 or ZYX cDNA overexpression. PHIP knockdown produced substantial suppression of tumor growth upon intracranial implantation, as well as significantly reduced microvessel density and secreted VEGF levels. PHIP copy number was elevated in the classical glioblastoma subtype and correlated with elevated EGFR levels. These results demonstrate PHIP's role in regulating the actin cytoskeleton, focal adhesion dynamics, and tumor cell motility, and identify PHIP as a key driver of glioblastoma migration and invasion.

PHIP as a therapeutic target for driver-negative subtypes of melanoma, breast, and lung cancer.

The identification and targeting of key molecular drivers of melanoma and breast and lung cancer have substantially improved their therapy. However, subtypes of each of these three common, lethal solid tumors lack identified molecular drivers, and are thus not amenable to targeted therapies. Here we show that pleckstrin homology domain-interacting protein (PHIP) promotes the progression of these "driver-negative" tumors. Suppression of PHIP expression significantly inhibited both tumor cell proliferation and invasion, coordinately suppressing phosphorylated AKT, cyclin D1, and talin1 expression in all three tumor types. Furthermore, PHIP's targetable bromodomain is functional, as it specifically binds the histone modification H4K91ac. Analysis of TCGA profiling efforts revealed PHIP overexpression in triple-negative and basal-like breast cancer, as well as in the bronchioid subtype of nonsmall cell lung cancer. These results identify a role for PHIP in the progression of melanoma and breast and lung cancer subtypes lacking identified targeted therapies. The use of selective, anti-PHIP bromodomain inhibitors may thus yield a broad-based, molecularly targeted therapy against currently nontargetable tumors.

Drug responses are conserved across patient-derived xenograft models of melanoma leading to identification of novel drug combination therapies.

BACKGROUND: Patient-derived xenograft (PDX) mouse tumour models can predict response to therapy in patients. Predictions made from PDX cultures (PDXC) would allow for more rapid and comprehensive evaluation of potential treatment options for patients, including drug combinations. METHODS: We developed a PDX library of BRAF-mutant metastatic melanoma, and a high-throughput drug-screening (HTDS) platform utilising clinically relevant drug exposures. We then evaluated 34 antitumor agents across eight melanoma PDXCs, compared drug response to BRAF and MEK inhibitors alone or in combination with PDXC and the corresponding PDX, and investigated novel drug combinations targeting BRAF inhibitor-resistant melanoma. RESULTS: The concordance of cancer-driving mutations across patient, matched PDX and subsequent PDX generations increases as variant allele frequency (VAF) increases. There was a high correlation in the magnitude of response to BRAF and MEK inhibitors between PDXCs and corresponding PDXs. PDXCs and corresponding PDXs from metastatic melanoma patients that progressed on standard-of-care therapy demonstrated similar resistance patterns to BRAF and MEK inhibitor therapy. Importantly, HTDS identified novel drug combinations to target BRAF-resistant melanoma. CONCLUSIONS: The biological consistency observed between PDXCs and PDXs suggests that PDXCs may allow for a rapid and comprehensive identification of treatments for aggressive cancers, including combination therapies.

Molecular subclasses of high-grade glioma predict prognosis, delineate a pattern of disease progression, and resemble stages in neurogenesis.

Previously undescribed prognostic subclasses of high-grade astrocytoma are identified and discovered to resemble stages in neurogenesis. One tumor class displaying neuronal lineage markers shows longer survival, while two tumor classes enriched for neural stem cell markers display equally short survival. Poor prognosis subclasses exhibit markers either of proliferation or of angiogenesis and mesenchyme. Upon recurrence, tumors frequently shift toward the mesenchymal subclass. Chromosomal locations of genes distinguishing tumor subclass parallel DNA copy number differences between subclasses. Functional relevance of tumor subtype molecular signatures is suggested by the ability of cell line signatures to predict neurosphere growth. A robust two-gene prognostic model utilizing PTEN and DLL3 expression suggests that Akt and Notch signaling are hallmarks of poor prognosis versus better prognosis gliomas, respectively.

Platelet-derived growth factor-alpha receptor activation is required for human cytomegalovirus infection.

Human cytomegalovirus (HCMV) is a ubiquitous human herpesvirus that can cause life-threatening disease in the fetus and the immunocompromised host. Upon attachment to the cell, the virus induces robust inflammatory, interferon- and growth-factor-like signalling. The mechanisms facilitating viral entry and gene expression are not clearly understood. Here we show that platelet-derived growth factor-alpha receptor (PDGFR-alpha) is specifically phosphorylated by both laboratory and clinical isolates of HCMV in various human cell types, resulting in activation of the phosphoinositide-3-kinase (PI(3)K) signalling pathway. Upon stimulation by HCMV, tyrosine-phosphorylated PDGFR-alpha associated with the p85 regulatory subunit of PI(3)K and induced protein kinase B (also known as Akt) phosphorylation, similar to the genuine ligand, PDGF-AA. Cells in which PDGFR-alpha was genetically deleted or functionally blocked were non-permissive to HCMV entry, viral gene expression or infectious virus production. Re-introducing human PDGFRA gene into knockout cells restored susceptibility to viral entry and essential viral gene expression. Blockade of receptor function with a humanized PDGFR-alpha blocking antibody (IMC-3G3) or targeted inhibition of its kinase activity with a small molecule (Gleevec) completely inhibited HCMV viral internalization and gene expression in human epithelial, endothelial and fibroblast cells. Viral entry in cells harbouring endogenous PDGFR-alpha was competitively inhibited by pretreatment with PDGF-AA. We further demonstrate that HCMV glycoprotein B directly interacts with PDGFR-alpha, resulting in receptor tyrosine phosphorylation, and that glycoprotein B neutralizing antibodies inhibit HCMV-induced PDGFR-alpha phosphorylation. Taken together, these data indicate that PDGFR-alpha is a critical receptor required for HCMV infection, and thus a target for novel anti-viral therapies.

The Irreversible FGFR Inhibitor KIN-3248 Overcomes FGFR2 Kinase Domain Mutations.

PURPOSE: FGFR2 and FGFR3 show oncogenic activation in many cancer types, often through chromosomal fusion or extracellular domain mutation. FGFR2 and FGFR3 alterations are most prevalent in intrahepatic cholangiocarcinoma (ICC) and bladder cancers, respectively, and multiple selective reversible and covalent pan-FGFR tyrosine kinase inhibitors (TKI) have been approved in these contexts. However, resistance, often due to acquired secondary mutations in the FGFR2/3 kinase domain, limits efficacy. Resistance is typically polyclonal, involving a spectrum of different mutations that most frequently affect the molecular brake and gatekeeper residues (N550 and V565 in FGFR2). EXPERIMENTAL DESIGN: Here, we characterize the activity of the next-generation covalent FGFR inhibitor, KIN-3248, in preclinical models of FGFR2 fusion+ ICC harboring a series of secondary kinase domain mutations, in vitro and in vivo. We also test select FGFR3 alleles in bladder cancer models. RESULTS: KIN-3248 exhibits potent selectivity for FGFR1-3 and retains activity against various FGFR2 kinase domain mutations, in addition to being effective against FGFR3 V555M and N540K mutations. Notably, KIN-3248 activity extends to the FGFR2 V565F gatekeeper mutation, which causes profound resistance to currently approved FGFR inhibitors. Combination treatment with EGFR or MEK inhibitors potentiates KIN-3248 efficacy in vivo, including in models harboring FGFR2 kinase domain mutations. CONCLUSIONS: Thus, KIN-3248 is a novel FGFR1-4 inhibitor whose distinct activity profile against FGFR kinase domain mutations highlights its potential for the treatment of ICC and other FGFR-driven cancers.

Discovery of KIN-3248, An Irreversible, Next Generation FGFR Inhibitor for the Treatment of Advanced Tumors Harboring FGFR2 and/or FGFR3 Gene Alterations.

Fibroblast growth factor receptor (FGFR) alterations are present as oncogenic drivers and bypass mechanisms in many forms of cancer. These alterations can include fusions, amplifications, rearrangements, and mutations. Acquired drug resistance to current FGFR inhibitors often results in disease progression and unfavorable outcomes for patients. Genomic profiling of tumors refractory to current FGFR inhibitors in the clinic has revealed several acquired driver alterations that could be the target of next generation therapeutics. Herein, we describe how structure-based drug design (SBDD) was used to enable the discovery of the potent and kinome selective pan-FGFR inhibitor KIN-3248, which is active against many acquired resistance mutations. KIN-3248 is currently in phase I clinical development for the treatment of advanced tumors harboring FGFR2 and/or FGFR3 gene alterations.

Dual Targeting of EGFR and MTOR Pathways Inhibits Glioblastoma Growth by Modulating the Tumor Microenvironment.

Glioblastoma's (GBM) aggressive growth is driven by redundant activation of a myriad of signaling pathways and genomic alterations in tyrosine kinase receptors, such as epidermal growth factor receptor (EGFR), which is altered in over 50% of cases. Single agents targeting EGFR have not proven effective against GBM. In this study, we aimed to identify an effective anti-tumor regimen using pharmacogenomic testing of patient-derived GBM samples, in culture and in vivo. High-throughput pharmacological screens of ten EGFR-driven GBM samples identified the combination of erlotinib (EGFRi) and MLN0128 (a mammalian target of rapamycin inhibitor, or MTORi) as the most effective at inhibiting tumor cell viability. The anti-tumor activity of erlonitib+MLN0128 was synergistic and produced inhibition of the p-EGFR, mitogen-activated protein kinase (MAPK), and Phosphoinositide 3-kinase (PI3K) pathways in culture. Using an orthotopic murine model of GBM, we show that erlotinib+MLN0128 inhibited tumor growth in vivo and significantly prolonged the survival of tumor-bearing mice. Expression profiling of tumor tissues from treated mice revealed a unique gene signature induced by erlotinib+MLN0128, consisting of downregulation of immunosuppressive chemokines in the tumor microenvironment, including C-C motif chemokine ligand 2 (CCL2) and periostin. Lower periostin levels resulted in the inhibition of Iba1+ (tumor-promoting) macrophage infiltration of GBM xenografts. Taken together, our results demonstrate that pharmacological co-targeting of EGFR and MTOR using clinically available drugs represents an effective treatment paradigm for EGFR-driven GBMs, acting both by inhibiting tumor cell growth and modulating the immune tumor microenvironment.

Functional genomic analysis of adult and pediatric brain tumor isolates.

Background: Adult and pediatric tumors display stark differences in their mutation spectra and chromosome alterations. Here, we attempted to identify common and unique gene dependencies and their associated biomarkers among adult and pediatric tumor isolates using functional genetic lethal screens and computational modeling. Methods: We performed CRISRP-Cas9 lethality screens in two adult glioblastoma (GBM) tumor isolates and five pediatric brain tumor isolates representing atypical teratoid rhabdoid tumors (ATRT), diffuse intrinsic pontine glioma, GBM, and medulloblastoma. We then integrated the screen results with machine learning-based gene-dependency models generated from data from >900 cancer cell lines. Results: We found that >50% of candidate dependencies of 280 identified were shared between adult GBM tumors and individual pediatric tumor isolates. 68% of screen hits were found as nodes in our network models, along with shared and tumor-specific predictors of gene dependencies. We investigated network predictors associated with ADAR, EFR3A, FGFR1 (pediatric-specific), and SMARCC2 (ATRT-specific) gene dependency among our tumor isolates. Conclusions: The results suggest that, despite harboring disparate genomic signatures, adult and pediatric tumor isolates share a preponderance of genetic dependences. Further, combining data from primary brain tumor lethality screens with large cancer cell line datasets produced valuable insights into biomarkers of gene dependency, even for rare cancers. Importance of the Study: Our results demonstrate that large cancer cell lines data sets can be computationally mined to identify known and novel gene dependency relationships in adult and pediatric human brain tumor isolates. Gene dependency networks and lethality screen results represent a key resource for neuro-oncology and cancer research communities. We also highlight some of the challenges and limitations of this approach.

Pan-Cancer Pharmacogenomic Analysis of Patient-Derived Tumor Cells Using Clinically Relevant Drug Exposures.

As a result of tumor heterogeneity and solid cancers harboring multiple molecular defects, precision medicine platforms in oncology are most effective when both genetic and pharmacologic determinants of a tumor are evaluated. Expandable patient-derived xenograft (PDX) mouse tumor and corresponding PDX culture (PDXC) models recapitulate many of the biological and genetic characteristics of the original patient tumor, allowing for a comprehensive pharmacogenomic analysis. Here, the somatic mutations of 23 matched patient tumor and PDX samples encompassing four cancers were first evaluated using next-generation sequencing (NGS). 19 antitumor agents were evaluated across 78 patient-derived tumor cultures using clinically relevant drug exposures. A binarization threshold sensitivity classification determined in culture (PDXC) was used to identify tumors that best respond to drug in vivo (PDX). Using this sensitivity classification, logic models of DNA mutations were developed for 19 antitumor agents to predict drug response. We determined that the concordance of somatic mutations across patient and corresponding PDX samples increased as variant allele frequency increased. Notable individual PDXC responses to specific drugs, as well as lineage-specific drug responses were identified. Robust responses identified in PDXC were recapitulated in vivo in PDX-bearing mice and logic modeling determined somatic gene mutation(s) defining response to specific antitumor agents. In conclusion, combining NGS of primary patient tumors, high-throughput drug screen using clinically relevant doses, and logic modeling, can provide a platform for understanding response to therapeutic drugs targeting cancer.

Cannabidiol inhibits RAD51 and sensitizes glioblastoma to temozolomide in multiple orthotopic tumor models.

Background: Cannabidiol (CBD), a nonpsychoactive cannabinoid with a low toxicity profile, has been shown to produce antitumor activity across cancers in part through selective production of reactive oxygen species (ROS) in tumor cells. The alkylating agent, temozolomide (TMZ), is standard of care for treatment of glioblastoma (GBM). It can trigger increased ROS to induce DNA damage. It has also been reported that downregulating the expression of RAD51, an important DNA damage repair protein, leads to sensitization of GBM to TMZ. Methods: We determined the extent to which CBD enhanced the antitumor activity of TMZ in multiple orthotopic models of GBM. In addition, we investigated the potential for CBD to enhance the antitumor activity of TMZ through production of ROS and modulation of DNA repair pathways. Results: CBD enhanced the activity of TMZ in U87 MG and U251 GBM cell lines and in patient-derived primary GBM163 cells leading to stimulation of ROS, activation of the ROS sensor AMP-activated protein kinase (AMPK), and upregulation of the autophagy marker LC3A. CBD produced a sensitization of U87 and GBM163-derived intracranial (i.c.) tumors to TMZ and significantly increased survival of tumor-bearing mice. However, these effects were not observed in orthotopic models derived from GBM with intact methylguanine methyltransferase (MGMT) expression. We further demonstrate that CBD inhibited RAD51 expression in MGMT-methylated models of GBM, providing a potential mechanism for tumor sensitization to TMZ by CBD. Conclusion: These data support the potential therapeutic benefits of using CBD to enhance the antitumor activity of TMZ in GBM patients.

Pitfalls and Rewards of Setting Up a Liquid Biopsy Approach for the Detection of Driver Mutations in Circulating Tumor DNAs: Our Institutional Experience.

We describe our institutional experience of developing a liquid biopsy approach using circulating tumor DNA (ctDNA) analysis for personalized medicine in cancer patients, focusing on the hurdles encountered during the multistep process in order to benefit other investigators wishing to set up this type of study in their institution. Blood samples were collected at the time of cancer surgery from 209 patients with one of nine different cancer types. Extracted tumor DNA and circulating cell-free DNA were sequenced using cancer-specific panels and the Illumina MiSeq machine. Almost half of the pairs investigated were uninformative, mostly because there was no trackable pathogenic mutation detected in the original tumor. The pairs with interpretable data corresponded to 107 patients. Analysis of 48 gene sequences common to both panels was performed and revealed that about 40% of these pairs contained at least one driver mutation detected in the DNA extracted from plasma. Here, we describe the choice of our overall approach, the selection of the cancer panels, and the difficulties encountered during the multistep process, including the use of several tumor types and in the data analysis. We also describe some case reports using longitudinal samples, illustrating the potential advantages and rewards in performing ctDNA sequencing to monitor tumor burden or guide treatment for cancer patients.

Cannabidiol Treatment Results in a Common Gene Expression Response Across Aggressive Cancer Cells from Various Origins.

Background: We previously reported that cannabidiol (CBD), a cannabinoid with a low toxicity profile, downregulated the expression of the prometastatic gene inhibitor of DNA binding 1 (ID1) in cancer cells, leading to inhibition of tumor progression in vivo. While CBD is broadly used, including in the self-medication of cancer patients, and CBD-based therapies are undergoing clinical evaluation for cancer treatment, its mechanisms of action are still poorly understood. Methods: In this study, using microarray analysis and Western blot analysis for validation, we attempted to identify the full spectrum of genes regulated by CBD across various aggressive cancer cell lines, including the breast, brain, head and neck, and prostate. Results: We confirmed that ID1 was a major target downregulated by CBD and also discovered that CBD inhibited FOXM1 (Forkhead box M1), a transcriptional activator involved in cell proliferation, while simultaneously upregulating GDF15 (growth differentiation factor 15), a cytokine associated with tissue differentiation. Conclusion: Our results suggest that, by modulating expression of shared key cancer-driving genes, CBD could represent a promising nontoxic therapeutic for treating tumors of various origins.

Niraparib Suppresses Cholangiocarcinoma Tumor Growth by Inducing Oxidative and Replication Stress.

Cholangiocarcinoma (CCA) is the second most common hepatobiliary cancer, an aggressive malignancy with limited therapeutic options. PARP (poly (ADP-ribose) polymerase) 1 and 2 are important for deoxyribonucleotide acid (DNA) repair and maintenance of genomic stability. PARP inhibitors (PARPi) such as niraparib have been approved for different malignancies with genomic alteration in germline BRCA and DNA damage response (DDR) pathway genes. Genomic alterations were analyzed in DDR genes in CCA samples employing The Cancer Genome Atlas (TCGA) database. Mutations were observed in various DDR genes, and 35.8% cases had alterations in at least one of three genes (ARID1A, BAP1 and ATM), suggesting their susceptibility to PARPi. Niraparib treatment suppressed cancer cell viability and survival, and also caused G2/M cell cycle arrest in patient-derived xenograft cells lines (PDXC) and established CCA cells harboring DDR gene mutations. PARPi treatment also induced apoptosis and caspase3/7 activity in PDXC and CCA cell lines, and substantially reduced expression of BCL2, BCL-XL and MCL1 proteins. Niraparib caused a significant increase in oxidative stress, and induced activation of DNA damage markers, phosphorylation of CHK2 and replication fork stalling. Importantly, niraparib, in combination with gemcitabine, produced sustained and robust inhibition of tumor growth in vivo in a patient-derived xenograft (PDX) model more effectively than either treatment alone. Furthermore, tissue samples from mice treated with niraparib and gemcitabine display significantly lower expression levels of pHH3 and Ki-67, which are a mitotic and proliferative marker, respectively. Taken together, our results indicate niraparib as a novel therapeutic agent alone or in combination with gemcitabine for CCA.

Nuclear Receptor Coactivator NCOA3 Regulates UV Radiation-Induced DNA Damage and Melanoma Susceptibility.

Melanoma occurs as a consequence of inherited susceptibility to the disease and exposure to UV radiation (UVR) and is characterized by uncontrolled cellular proliferation and a high mutational load. The precise mechanisms by which UVR contributes to the development of melanoma remain poorly understood. Here we show that activation of nuclear receptor coactivator 3 (NCOA3) promotes melanomagenesis through regulation of UVR sensitivity, cell-cycle progression, and circumvention of the DNA damage response (DDR). Downregulation of NCOA3 expression, either by genetic silencing or small-molecule inhibition, significantly suppressed melanoma proliferation in melanoma cell lines and patient-derived xenografts. NCOA3 silencing suppressed expression of xeroderma pigmentosum C and increased melanoma cell sensitivity to UVR. Suppression of NCOA3 expression led to activation of DDR effectors and reduced expression of cyclin B1, resulting in G2-M arrest and mitotic catastrophe. A SNP in NCOA3 (T960T) reduced NCOA3 protein expression and was associated with decreased melanoma risk, given a significantly lower prevalence in a familial melanoma cohort than in a control cohort without cancer. Overexpression of wild-type NCOA3 promoted melanocyte survival following UVR and was accompanied by increased levels of UVR-induced DNA damage, both of which were attenuated by overexpression of NCOA3 (T960T). These results describe NCOA3-regulated pathways by which melanoma can develop, with germline NCOA3 polymorphisms enabling enhanced melanocyte survival in the setting of UVR exposure, despite an increased mutational burden. They also identify NCOA3 as a novel therapeutic target for melanoma. SIGNIFICANCE: This study explores NCOA3 as a regulator of the DDR and a therapeutic target in melanoma, where activation of NCOA3 contributes to melanoma development following exposure to ultraviolet light.

Prevalence of Homologous Recombination Pathway Gene Mutations in Melanoma: Rationale for a New Targeted Therapeutic Approach.

Homologous recombination DNA damage repair (HR-DDR) deficient patients with various solid tumors have been treated with PARP inhibitors. However, the clinical characteristics of patients with melanoma who have HR-DDR gene mutations and the consequences of PARP inhibition are poorly understood. We compared the commercially available next-generation sequencing data from 84 patients with melanomas from our institution with a dataset of 1,986 patients as well as 1,088 patients profiled in cBioportal. In total, 21.4% of patients had ≥1 functional HR-DDR mutation, most commonly involving BRCA1, ARID1A, ATM, ATR, and FANCA. Concurrent NF1, BRAF, and NRAS mutations were found in 39%, 39%, and 22% of cases, respectively. HR-DDR gene mutation was associated with high tumor mutational burden and clinical response to checkpoint blockade. A higher prevalence of HR-DDR mutations was observed in the datasets from Foundation Medicine (Cambridge, CA) and those from the Cancer Genome Atlas. Treatment of HR-DDR‒mutated patient-derived xenograft models of melanoma with PARP inhibitor produced significant antitumor activity in vivo and was associated with increased apoptotic activity. RNA sequencing analysis of PARP inhibitor-treated tumors indicated alterations in the pathways involving extracellular matrix remodeling, cell adhesion, and cell-cycle progression. Melanomas with HR-DDR mutations represent a unique subset, which is more likely to benefit from checkpoint blockade and may be targeted with PARP inhibitor.

Dinaciclib, a cyclin-dependent kinase inhibitor, suppresses cholangiocarcinoma growth by targeting CDK2/5/9.

Cholangiocarcinoma (CCA) is a highly invasive cancer, diagnosed at an advanced stage, and refractory to surgical intervention and chemotherapy. Cyclin-dependent kinases (CDKs) regulate cell cycle progression and transcriptional processes, and are considered potential therapeutic targets for cancer. Dinaciclib is a small molecule multi-CDK inhibitor targeting CDK 2/5/9. In this study, the therapeutic efficacy of dinaciclib was assessed using patient-derived xenograft cells (PDXC) and CCA cell lines. Treatment with dinaciclib significantly suppressed cell proliferation, induced caspase 3/7 levels and apoptotic activity in PDXC and CCA cell lines. Dinaciclib suppressed expression of its molecular targets CDK2/5/9, and anti-apoptotic BCL-XL and BCL2 proteins. Despite the presence of cyclin D1 amplification in the PDXC line, palbociclib treatment had no effect on cell proliferation, cell cycle or apoptosis in the PDXC as well as other CCA cell lines. Importantly, dinaciclib, in combination with gemcitabine, produced a robust and sustained inhibition of tumor progression in vivo in a PDX mouse model, greater than either of the treatments alone. Expression levels of two proliferative markers, phospho-histone H3 and Ki-67, were substantially suppressed in samples treated with the combination regimen. Our results identify dinaciclib as a novel and potent therapeutic agent alone or in combination with gemcitabine for the treatment of CCA.

Tissues Harvested Using an Automated Surgical Approach Confirm Molecular Heterogeneity of Glioblastoma and Enhance Specimen's Translational Research Value.

Glioblastoma (GBM) is the most aggressive primary brain tumor in adults. Designing effective individualized therapies for GBM requires quality fresh tissue specimens, and a comprehensive molecular profile of this highly heterogenous neoplasm. Novel neuro-surgical approaches, such as the automated resection NICO Myriad™ system, are increasingly used by neurosurgeons to better reach the invasive front of tumors. However, no information exists on how harvesting GBM tissue using this approach may impact the translational research value of the sample. Here, we set out to characterize matched specimens from 15 patients, where one tissue sample was obtained using traditional tumor de-bulking (herein referred to as "en bloc" sample), and the other sample was obtained using the MyriadTM System (herein referred to as "Myriad" sample). We investigated the fidelity of patient derived xenografts (PDXs) for each sample type to the corresponding human tissues and evaluated the added value of sequencing both samples for each patient. Matched en bloc and Myriad samples processed in parallel, were subjected to the following assays: cell viability, self-renewal, in vivo tumorigenicity using an orthotopic model of glioma, genomic sequencing, and pharmacological testing using PI3K-MTOR pathway inhibitors. Our results demonstrate that primary GBM cultures derived from matched specimens grew at similar rates (correlation coefficient R = 0.72), generated equivalent number of neurospheres, and had equivalent tumorigenic potential in vivo (mouse survival correlation coefficient R = 0.93). DNA Sequencing using the Illumina tumor panel amplicons revealed over 70% concordance in non-synonymous mutations between matched human GBM specimens. PDX genomic profiles were also highly concordant with the corresponding patient tissues (>70%). RNA sequencing of paired GBM samples revealed unique genomic variants and differential gene expression between the en bloc and Myriad specimens, with the former molecularly resembling the "tumor core" and the latter resembling the "invasive tumor front" signature. Functionally, we show that primary-derived GBM cells-obtained after fresh specimen's dissociation-are more effectively growth-inhibited by co-targeting non-overlapping mutations enriched in each sample type, suggesting that profiling both specimens more adequately capture the molecular heterogeneity of GBM and may enhance the design accuracy and efficacy of individualized therapies.

Durable multitransgene expression in vivo using systemic, nonviral DNA delivery.

Recombinant adeno-associated virus (AAV) vectors are transforming therapies for rare human monogenic deficiency diseases. However, adaptive immune responses to AAV and its limited DNA insert capacity, restrict their therapeutic potential. HEDGES (high-level extended duration gene expression system), a nonviral DNA- and liposome-based gene delivery platform, overcomes these limitations in immunocompetent mice. Specifically, one systemic HEDGES injection durably produces therapeutic levels of transgene-encoded human proteins, including FDA-approved cytokines and monoclonal antibodies, without detectable integration into genomic DNA. HEDGES also controls protein production duration from <3 weeks to >1.5 years, does not induce anti-vector immune responses, is reexpressed for prolonged periods following reinjection, and produces only transient minimal toxicity. HEDGES can produce extended therapeutic levels of multiple transgene-encoded therapeutic human proteins from DNA inserts >1.5-fold larger than AAV-based therapeutics, thus creating combinatorial interventions to effectively treat common polygenic diseases driven by multigenic abnormalities.