Combination of Type I and Type II MET Tyrosine Kinase Inhibitors as Therapeutic Approach to Prevent Resistance.

MET-targeted therapies are clinically effective in -amplified and exon 14 deletion mutant (ex14) non-small cell lung cancers (NSCLCs), but their efficacy is limited by the development of drug resistance. Structurally distinct MET tyrosine kinase inhibitors (TKIs) (type I/II) have been developed or are under clinical evaluation, which may overcome MET-mediated drug resistance mechanisms. In this study, we assess secondary MET mutations likely to emerge in response to treatment with single-agent or combinations of type I/type II MET TKIs using TPR-MET transformed Ba/F3 cell mutagenesis assays.

EGFR Inhibition Enhances the Cellular Uptake and Antitumor-Activity of the HER3 Antibody-Drug Conjugate HER3-DXd.

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) are the standard-of-care treatment for -mutant non-small cell lung cancers (NSCLC). However, most patients develop acquired drug resistance to EGFR TKIs. HER3 is a unique pseudokinase member of the ERBB family that functions by dimerizing with other ERBB family members (EGFR and HER2) and is frequently overexpressed in -mutant NSCLC.

Concurrent Dexamethasone Limits the Clinical Benefit of Immune Checkpoint Blockade in Glioblastoma.

Purpose: Dexamethasone, a uniquely potent corticosteroid, is frequently administered to patients with brain tumors to decrease tumor-associated edema, but limited data exist describing how dexamethasone affects the immune system systemically and intratumorally in patients with glioblastoma (GBM), particularly in the context of immunotherapy.

Experimental Design: We evaluated the dose-dependent effects of dexamethasone when administered with programmed cell death 1 (PD-1) blockade and/or radiotherapy in immunocompetent C57BL/6 mice with syngeneic GL261 and CT-2A GBM tumors. Clinically, the effect of dexamethasone on survival was evaluated in 181 patients with isocitrate dehydrogenase (IDH) wild-type GBM treated with PD-(L)1 blockade, with adjustment for relevant prognostic factors.

Dynamic single-cell RNA sequencing identifies immunotherapy persister cells following PD-1 blockade.

Resistance to oncogene-targeted therapies involves discrete drug-tolerant persister cells, originally discovered through in vitro assays. Whether a similar phenomenon limits efficacy of programmed cell death 1 (PD-1) blockade is poorly understood. Here, we performed dynamic single-cell RNA-Seq of murine organotypic tumor spheroids undergoing PD-1 blockade, identifying a discrete subpopulation of immunotherapy persister cells (IPCs) that resisted CD8+ T cell-mediated killing.

Treatment-Induced Tumor Dormancy through YAP-Mediated Transcriptional Reprogramming of the Apoptotic Pathway.

Eradicating tumor dormancy that develops following epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) treatment of EGFR-mutant non-small cell lung cancer, is an attractive therapeutic strategy but the mechanisms governing this process are poorly understood. Blockade of ERK1/2 reactivation following EGFR TKI treatment by combined EGFR/MEK inhibition uncovers cells that survive by entering a senescence-like dormant state characterized by high YAP/TEAD activity. YAP/TEAD engage the epithelial-to-mesenchymal transition transcription factor SLUG to directly repress pro-apoptotic BMF, limiting drug-induced apoptosis.

The CHK1 Inhibitor Prexasertib Exhibits Monotherapy Activity in High-Grade Serous Ovarian Cancer Models and Sensitizes to PARP Inhibition.

Purpose: PARP inhibitors are approved for the treatment of high-grade serous ovarian cancers (HGSOC). Therapeutic resistance, resulting from restoration of homologous recombination (HR) repair or replication fork stabilization, is a pressing clinical problem. We assessed the activity of prexasertib, a checkpoint kinase 1 (CHK1) inhibitor known to cause replication catastrophe, as monotherapy and in combination with the PARP inhibitor olaparib in preclinical models of HGSOC, including those with acquired PARP inhibitor resistance.

The Combined Effect of FGFR Inhibition and PD-1 Blockade Promotes Tumor-Intrinsic Induction of Antitumor Immunity.

The success of targeted or immune therapies is often hampered by the emergence of resistance and/or clinical benefit in only a subset of patients. We hypothesized that combining targeted therapy with immune modulation would show enhanced antitumor responses. Here, we explored the combination potential of erdafitinib, a fibroblast growth factor receptor (FGFR) inhibitor under clinical development, with PD-1 blockade in an autochthonous FGFR2/p53 lung cancer mouse model.

Targeting MYC dependency in ovarian cancer through inhibition of CDK7 and CDK12/13.

High-grade serous ovarian cancer is characterized by extensive copy number alterations, among which the amplification of oncogene occurs in nearly half of tumors. We demonstrate that ovarian cancer cells highly depend on MYC for maintaining their oncogenic growth, indicating MYC as a therapeutic target for this difficult-to-treat malignancy. However, targeting MYC directly has proven difficult.

Suppression of STING Associated with LKB1 Loss in KRAS-Driven Lung Cancer.

-driven lung cancers frequently inactivate and/or , defining tumor subclasses with emerging clinical relevance. Specifically, - (KL)-mutant lung cancers are particularly aggressive, lack PD-L1, and respond poorly to immune checkpoint blockade (ICB). The mechanistic basis for this impaired immunogenicity, despite the overall high mutational load of -mutant lung cancers, remains obscure.

A High-Throughput Immune-Oncology Screen Identifies EGFR Inhibitors as Potent Enhancers of Antigen-Specific Cytotoxic T-lymphocyte Tumor Cell Killing.

We developed a screening assay in which luciferized ID8 expressing OVA was cocultured with transgenic CD8 T cells specifically recognizing the model antigen in an H-2b-restricted manner. The assay was screened with a small-molecule library to identify compounds that inhibit or enhance T cell-mediated killing of tumor cells. Erlotinib, an EGFR inhibitor, was the top compound that enhanced T-cell killing of tumor cells.

Overcoming Resistance to Dual Innate Immune and MEK Inhibition Downstream of KRAS.

Despite extensive efforts, oncogenic KRAS remains resistant to targeted therapy. Combined downstream RAL-TBK1 and MEK inhibition induces only transient lung tumor shrinkage in KRAS-driven genetically engineered mouse models (GEMMs). Using the sensitive KRAS;LKB1 (KL) mutant background, we identify YAP1 upregulation and a therapy-induced secretome as mediators of acquired resistance.

Amplification of Wild-type Imparts Resistance to Crizotinib in Exon 14 Mutant Non-Small Cell Lung Cancer.

Purpose: MET inhibitors can be effective therapies in patients with exon 14 (ex14) mutant non-small cell lung cancer (NSCLC). However, long-term efficacy is limited by the development of drug resistance. In this study, we characterize acquired amplification of wild-type (WT) as a molecular mechanism behind crizotinib resistance in three cases of ex14-mutant NSCLC and propose a combination therapy to target it.

Recurrent ubiquitin B silencing in gynecological cancers establishes dependence on ubiquitin C.

Transcriptional repression of ubiquitin B (UBB) is a cancer-subtype-specific alteration that occurs in a substantial population of patients with cancers of the female reproductive tract. UBB is 1 of 2 genes encoding for ubiquitin as a polyprotein consisting of multiple copies of ubiquitin monomers. Silencing of UBB reduces cellular UBB levels and results in an exquisite dependence on ubiquitin C (UBC), the second polyubiquitin gene.

Profiling of PD-1 Blockade Using Organotypic Tumor Spheroids.

systems that incorporate features of the tumor microenvironment and model the dynamic response to immune checkpoint blockade (ICB) may facilitate efforts in precision immuno-oncology and the development of effective combination therapies. Here, we demonstrate the ability to interrogate response to ICB using murine- and patient-derived organotypic tumor spheroids (MDOTS/PDOTS). MDOTS/PDOTS isolated from mouse and human tumors retain autologous lymphoid and myeloid cell populations and respond to ICB in short-term three-dimensional microfluidic culture.

Establishment of Patient-Derived Tumor Xenograft Models of Epithelial Ovarian Cancer for Preclinical Evaluation of Novel Therapeutics.

Ovarian cancer is the leading cause of death from gynecologic malignancy in the United States, with high rates of recurrence and eventual resistance to cytotoxic chemotherapy. Model systems that allow for accurate and reproducible target discovery and validation are needed to support further drug development in this disease. Clinically annotated patient-derived xenograft (PDX) models were generated from tumor cells isolated from the ascites or pleural fluid of patients undergoing clinical procedures.

Pathological glycogenesis through glycogen synthase 1 and suppression of excessive AMP kinase activity in myeloid leukemia cells.

The rapid proliferation of myeloid leukemia cells is highly dependent on increased glucose metabolism. Through an unbiased metabolomics analysis of leukemia cells, we found that the glycogenic precursor UDP-D-glucose is pervasively upregulated, despite low glycogen levels. Targeting the rate-limiting glycogen synthase 1 (GYS1) not only decreased glycolytic flux but also increased activation of the glycogen-responsive AMP kinase (AMPK), leading to significant growth suppression.

Evaluating TBK1 as a therapeutic target in cancers with activated IRF3.

Unlabelled: TBK1 (TANK-binding kinase 1) is a noncanonical IκB protein kinase that phosphorylates and activates downstream targets such as IRF3 and c-Rel and, mediates NF-κB activation in cancer. Previous reports demonstrated synthetic lethality of TBK1 with mutant KRAS in non-small cell lung cancer (NSCLC); thus, TBK1 could be a novel target for treatment of KRAS-mutant NSCLC. Here, the effect of TBK1 on proliferation in a panel of cancer cells by both genetic and pharmacologic approaches was evaluated.