ABSTRACT
Cancer cells are highly heterogeneous at the transcriptional level and epigenetic state. Methods to study epigenetic heterogeneity are limited in throughput and information obtained per cell. Here, we adapted cytometry by time-of-flight (CyTOF) to analyze a wide panel of histone modifications in primary tumor-derived lines of diffused intrinsic pontine glioma (DIPG). DIPG is a lethal glioma, driven by a histone H3 lysine 27 mutation (H3-K27M). We identified two epigenetically distinct subpopulations in DIPG, reflecting inherent heterogeneity in expression of the mutant histone. These two subpopulations are robust across tumor lines derived from different patients and show differential proliferation capacity and expression of stem cell and differentiation markers. Moreover, we demonstrate the use of these high-dimensional data to elucidate potential interactions between histone modifications and epigenetic alterations during the cell cycle. Our work establishes new concepts for the analysis of epigenetic heterogeneity in cancer that could be applied to diverse biological systems.
Subject(s)
Brain Stem Neoplasms , Glioma , Brain Stem Neoplasms/genetics , Brain Stem Neoplasms/metabolism , Brain Stem Neoplasms/pathology , Chromatin/genetics , Epigenesis, Genetic , Glioma/metabolism , Histones/genetics , Histones/metabolism , Humans , MutationABSTRACT
Almost all attempts to date at gene therapy approaches for monogenetic disease have used the amino acid sequences of the natural protein. In the current study, we use a designed, thermostable form of glucocerebrosidase (GCase), the enzyme defective in Gaucher disease (GD), to attempt to alleviate neurological symptoms in a GD mouse that models type 3 disease, i.e. the chronic neuronopathic juvenile subtype. Upon injection of an AAVrh10 (adeno-associated virus, serotype rh10) vector containing the designed GCase (dGCase) into the left lateral ventricle of Gba-/-;Gbatg mice, a significant improvement in body weight and life-span was observed, compared to injection of the same mouse with the wild type enzyme (wtGCase). Moreover, a reduction in levels of glucosylceramide (GlcCer), and an increase in levels of GCase activity were seen in the right hemisphere of Gba-/-;Gbatg mice, concomitantly with a significant improvement in motor function, reduction of neuroinflammation and a reduction in mRNA levels of various genes shown previously to be elevated in the brain of mouse models of neurological forms of GD. Together, these data pave the way for the possible use of modified proteins in gene therapy for lysosomal storage diseases and other monogenetic disorders.
ABSTRACT
Electrophiles for covalent inhibitors that are suitable for in vivo administration are rare. While acrylamides are prevalent in FDA-approved covalent drugs, chloroacetamides are considered too reactive for such purposes. We report sulfamate-based electrophiles that maintain chloroacetamide-like geometry with tunable reactivity. In the context of the BTK inhibitor ibrutinib, sulfamate analogues showed low reactivity with comparable potency in protein labeling, in vitro, and cellular kinase activity assays and were effective in a mouse model of CLL. In a second example, we converted a chloroacetamide Pin1 inhibitor to a potent and selective sulfamate acetamide with improved buffer stability. Finally, we show that sulfamate acetamides can be used for covalent ligand-directed release (CoLDR) chemistry, both for the generation of "turn-on" probes as well as for traceless ligand-directed site-specific labeling of proteins. Taken together, this chemistry represents a promising addition to the list of electrophiles suitable for in vivo covalent targeting.
Subject(s)
Acetamides , Protein Kinase Inhibitors , Mice , Animals , Ligands , Protein Kinase Inhibitors/pharmacologyABSTRACT
The peptidyl-prolyl isomerase, Pin1, is exploited in cancer to activate oncogenes and inactivate tumor suppressors. However, despite considerable efforts, Pin1 has remained an elusive drug target. Here, we screened an electrophilic fragment library to identify covalent inhibitors targeting Pin1's active site Cys113, leading to the development of Sulfopin, a nanomolar Pin1 inhibitor. Sulfopin is highly selective, as validated by two independent chemoproteomics methods, achieves potent cellular and in vivo target engagement and phenocopies Pin1 genetic knockout. Pin1 inhibition had only a modest effect on cancer cell line viability. Nevertheless, Sulfopin induced downregulation of c-Myc target genes, reduced tumor progression and conferred survival benefit in murine and zebrafish models of MYCN-driven neuroblastoma, and in a murine model of pancreatic cancer. Our results demonstrate that Sulfopin is a chemical probe suitable for assessment of Pin1-dependent pharmacology in cells and in vivo, and that Pin1 warrants further investigation as a potential cancer drug target.
Subject(s)
Antineoplastic Agents/pharmacology , Enzyme Inhibitors/pharmacology , NIMA-Interacting Peptidylprolyl Isomerase/antagonists & inhibitors , Proto-Oncogene Proteins c-myc/antagonists & inhibitors , Animals , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/chemistry , Apoptosis/drug effects , Cell Proliferation/drug effects , Cell Survival/drug effects , Dose-Response Relationship, Drug , Drug Screening Assays, Antitumor , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Humans , Mice , Mice, Inbred C57BL , Molecular Structure , NIMA-Interacting Peptidylprolyl Isomerase/metabolism , Neoplasms, Experimental/drug therapy , Neoplasms, Experimental/metabolism , Neoplasms, Experimental/pathology , Proto-Oncogene Proteins c-myc/metabolism , Structure-Activity Relationship , Tumor Cells, CulturedABSTRACT
Metastatic ovarian cancer, the most lethal of gynecologic malignancies, is typically managed by debulking surgery, followed by chemotherapy. However, despite significant efforts, survival rate remains low. We have previously demonstrated, in mouse models, a specific systemic homing of labeled fibroblasts to solid ovarian tumors. Here, we demonstrate the feasibility of utilizing this specific homing of genetically modified fibroblasts for detection and targeted therapy of orthotopic metastatic ovarian carcinoma model in immune-deficient mice. Using an in vivo metastatic mouse model for ovarian cancer, we demonstrated that fibroblasts expressing fluorescent reporters injected intra-peritoneally, were specifically recruited to peritoneal tumor nodules (resulting in 93-100% co-localization). We further used fibroblasts over expressing the soluble receptor variant of VEGFR1 (s-Flt1). Mice bearing tumors were injected weekly with either control or s-Flt1 expressing fibroblasts. Injection of s-Flt1 expressing fibroblasts resulted in a significant reduction in the ascites volume, reduced vascularization of adherent metastases, and improved overall survival. Using fluorescently labeled fibroblasts for tumor detection with readily available intra-operative fluorescence imaging tools may be useful for tumor staging and directing biopsies or surgical efforts during exploratory or debulking surgery. Fibroblasts may serve as a beacon pointing to the otherwise invisible metastases in the peritoneal cavity of ovarian cancer patients. Utilizing the recruited fibroblasts also for targeted delivery of anti angiogenic or antitumor molecules may aid in controlling tumor progression. Thus, these results suggest a novel approach for targeting ovarian tumor metastases for both tumor detection and therapy.
Subject(s)
Fibroblasts/pathology , Neoplasms, Glandular and Epithelial/pathology , Ovarian Neoplasms/pathology , Animals , Carcinoma, Ovarian Epithelial , Cell Line, Transformed , Cell Line, Tumor , Female , Fibroblasts/metabolism , Fibroblasts/transplantation , Fluorescent Dyes/administration & dosage , Fluorescent Dyes/chemistry , Haplorhini , Heterografts , Humans , Mice , Mice, Nude , Neoplasms, Glandular and Epithelial/blood supply , Neoplasms, Glandular and Epithelial/diagnostic imaging , Neoplasms, Glandular and Epithelial/therapy , Ovarian Neoplasms/blood supply , Ovarian Neoplasms/diagnostic imaging , Ovarian Neoplasms/therapy , Vascular Endothelial Growth Factor Receptor-1/biosynthesisABSTRACT
MicroRNAs (miRNAs) were shown to be important for pancreas development, yet their roles in differentiated ß-cells remain unclear. Here, we show that miRNA inactivation in ß-cells of adult mice results in a striking diabetic phenotype. While islet architecture is intact and differentiation markers are maintained, Dicer1-deficient ß-cells show a dramatic decrease in insulin content and insulin mRNA. As a consequence of the change in insulin content, the animals become diabetic. We provide evidence for involvement of a set of miRNAs in regulating insulin synthesis. The specific knockdown of miR-24, miR-26, miR-182 or miR-148 in cultured ß-cells or in isolated primary islets downregulates insulin promoter activity and insulin mRNA levels. Further, miRNA-dependent regulation of insulin expression is associated with upregulation of transcriptional repressors, including Bhlhe22 and Sox6. Thus, miRNAs in the adult pancreas act in a new network that reinforces insulin expression by reducing the expression of insulin transcriptional repressors.
Subject(s)
DEAD-box RNA Helicases/physiology , Endoribonucleases/physiology , Insulin-Secreting Cells/metabolism , Insulin/genetics , Insulin/metabolism , MicroRNAs/physiology , Repressor Proteins/metabolism , Transcription, Genetic , Animals , Blotting, Western , Cell Differentiation , Cells, Cultured , Down-Regulation , Glucose Intolerance , Humans , Immunoenzyme Techniques , Insulin-Secreting Cells/cytology , Integrases/metabolism , Luciferases/metabolism , Mice , Mice, Knockout , MicroRNAs/antagonists & inhibitors , RNA, Messenger/genetics , Repressor Proteins/genetics , Reverse Transcriptase Polymerase Chain Reaction , Ribonuclease IIIABSTRACT
Diffuse midline gliomas (DMGs) are aggressive and fatal pediatric tumors of the central nervous system that are highly resistant to treatments. Lysine to methionine substitution of residue 27 on histone H3 (H3-K27M) is a driver mutation in DMGs, reshaping the epigenetic landscape of these cells to promote tumorigenesis. H3-K27M gliomas are characterized by deregulation of histone acetylation and methylation pathways, as well as the oncogenic MYC pathway. In search of effective treatment, we examined the therapeutic potential of dual targeting of histone deacetylases (HDACs) and MYC in these tumors. Treatment of H3-K27M patient-derived cells with Sulfopin, an inhibitor shown to block MYC-driven tumors in vivo, in combination with the HDAC inhibitor Vorinostat, resulted in substantial decrease in cell viability. Moreover, transcriptome and epigenome profiling revealed synergistic effect of this drug combination in downregulation of prominent oncogenic pathways such as mTOR. Finally, in vivo studies of patient-derived orthotopic xenograft models showed significant tumor growth reduction in mice treated with the drug combination. These results highlight the combined treatment with PIN1 and HDAC inhibitors as a promising therapeutic approach for these aggressive tumors.
Diffuse midline gliomas (DMGs) are among the most aggressive and fatal brain cancers in children. They are often associated with changes in histones, the proteins that control gene activity and give chromosomes their structure. Most children with DMGs, for example, share the same anomaly in their histone H3 protein (referred to as the H3-K27M mutation). This change affects how small chemical tags called methyl and acetyl groups can be added onto histone 3, which in turn alters the way the protein can switch genes on and off. As a result, tumours start to develop. One potential therapeutic strategy against DMGs is to use histone deacetylase inhibitors (HDACi), a promising type of drugs which inhibits the enzymes that remove acetyl groups from histones. Patients can develop resistance to HDACi, however, highlighting the need to explore other approaches. One possibility is to treat patients with several types of drugs, each usually targeting a distinct biological process that contributes to the emergence of cancer. This combined approach can have multiple benefits; the drugs potentially amplify each other's effect, for example, and it is also less likely for cells to become resistant to more than one compound at the time. In addition, each drug in the combination can be used in a lower dose to reduce side effects and benefit patients. DMG tumour cells often feature higher activity levels of a protein known as MYC, which can contribute to the growth of the tumour. Algranati, Oren et al. therefore set out to test whether combining an HDACi known as Vorinostat with a drug that blocks MYC activity (Sulfopin) can act as an effective treatment for this cancer. Tumour samples from eight DMG patients were treated with either Sulfopin alone, or Sulfopin in association with Vorinostat. Cells exposed to both drugs were less likely to survive, and additional genetic experiments showed that the combined treatment had resulted in pathways that promote tumour development being blocked. When both Sulfopin and Vorinostat were administered to mice made to grow human DMG tumors, the animals showed a greater reduction in tumor growth. Treatment options for DMG are usually limited, with chemotherapy often being ineffective and surgery impossible. The work by Algranati, Oren et al. suggests that combining HDACi and drugs targeting the MYC pathway is a strategy that should be examined further to determine whether clinical applications are possible.
Subject(s)
Glioma , Histone Deacetylase Inhibitors , Histone Deacetylases , Histones , Glioma/drug therapy , Glioma/genetics , Glioma/pathology , Humans , Animals , Histone Deacetylases/metabolism , Histone Deacetylases/genetics , Histones/metabolism , Histones/genetics , Histone Deacetylase Inhibitors/pharmacology , Mice , Proto-Oncogene Proteins c-myc/metabolism , Proto-Oncogene Proteins c-myc/genetics , Vorinostat/pharmacology , Antineoplastic Agents/pharmacology , Cell Survival/drug effects , Cell Line, Tumor , Child , Disease Models, Animal , Xenograft Model Antitumor AssaysABSTRACT
An in-house genotyping facility should aim to be more cost-effective than outsourced service and more reliable than genotyping performed by short-term employees or students of individual research groups. Reliable genotyping allows efficient and economical management of mice colonies and promotes accurate and reproducible research results. Here we provide a detailed description of our approach to establishing a genotyping core facility, relying on automated PCR assembly and high-resolution melting (HRM) analysis (first derivative). The workflow we devised was tightly managed by purpose-designed applications developed using MATLAB App Designer that allowed straightforward work planning, ensured sample tracking throughout the process, and provided a platform for reliable data analysis and generation of genotyping reports. We successfully transitioned PCR product analysis of more than 250 different target genes from standard gel electrophoresis to the more advanced HRM analysis. About 23% of the target genes required a redesign of primers to adapt to our protocol. The process was highly universal, and only 2% of the target genes required deviation from the standard PCR method to a more restricted protocol that reduces the amplification of nonspecific products. We currently run more than 1,000 PCR reactions weekly, of samples taken at weaning or experimental endpoint, and assemble a large variety of target genes in every PCR plate. We also showed that genotyping of blastocytes instead of embryos can serve as quality control of cryopreservation. Thus, our genotyping protocol promotes the 3Rs (Replacement, Reduction, and Refinement) principles. Our refined genotyping process facilitates cost-effective colony management, replaces tissue types as well as traditional methods with advanced ones, and provides reliable results in a timely manner. MATLAB codes and related data are available in supplementary materials and online.
ABSTRACT
BACKGROUND: Proteasome inhibitors are in use in treating certain types of cancers. These drugs inhibit the catalytic activity of the 20S proteasome, shared by all the different proteasome complexes. Inhibitors of the 26S-associated deubiquitinating activity explicitly inhibit the 26S proteasomal degradation of ubiquitinylated substrates. We have previously reported an alternative strategy that is based on reducing the 26S/20S ratio by depleting PSMD1, 6, and 11, the subunits of the 19S proteasome regulatory complex. Given the addiction of the many cancer types to a high 26S/20S ratio, the depletion strategy is highly effective in killing many aggressive cancer cell lines but not mouse and human immortalized and normal cells. METHODS: We used two aggressive cell lines, MDA-MB-231, a triple-negative breast tumor cell line, and OVCAR8, a high-grade ovary adenocarcinoma. Cell culture, mouse MDA-MB-231, OVCAR8 xenografts, and patient-derived ovarian cancer xenograft (PDX) models were transduced with lentivectors expressing PSMD1 shRNA. Tumor size was measured to follow treatment efficacy. RESULTS: Using different experimental strategies of expressing shRNA, we found that PSMD1 depletion, either by expressing PSMD1 shRNA in an inducible manner or in a constitutive manner, robustly inhibited MDA-MB-231, and OVCAR8 xenograft tumor growth. Furthermore, the PSMD1 depletion strategy compromised the growth of the PDX of primary ovarian cancer. CONCLUSION: Our results suggest that reducing the 26S/20S ratio might be a valuable strategy for treating drug-resistant aggressive types of cancers.
Subject(s)
Ovarian Neoplasms , Proteasome Endopeptidase Complex , Female , Humans , Cell Line , Cytoplasm/metabolism , Proteasome Endopeptidase Complex/genetics , Animals , Mice , Cell Line, TumorABSTRACT
Common methods to label cell surface proteins (CSPs) involve the use of fluorescently modified antibodies (Abs) or small-molecule-based ligands. However, optimizing the labeling efficiency of such systems, for example, by modifying them with additional fluorophores or recognition elements, is challenging. Herein we show that effective labeling of CSPs overexpressed in cancer cells and tissues can be obtained with fluorescent probes based on chemically modified bacteria. The bacterial probes (B-probes) are generated by non-covalently linking a bacterial membrane protein to DNA duplexes appended with fluorophores and small-molecule binders of CSPs overexpressed in cancer cells. We show that B-probes are exceptionally simple to prepare and modify because they are generated from self-assembled and easily synthesized components, such as self-replicating bacterial scaffolds and DNA constructs that can be readily appended, at well-defined positions, with various types of dyes and CSP binders. This structural programmability enabled us to create B-probes that can label different types of cancer cells with distinct colors, as well as generate very bright B-probes in which the multiple dyes are spatially separated along the DNA scaffold to avoid self-quenching. This enhancement in the emission signal enabled us to label the cancer cells with greater sensitivity and follow the internalization of the B-probes into these cells. The potential to apply the design principles underlying B-probes in therapy or inhibitor screening is also discussed here.
ABSTRACT
EGFR-specific tyrosine kinase inhibitors (TKIs), especially osimertinib, have changed lung cancer therapy, but secondary mutations confer drug resistance. Because other EGFR mutations promote dimerization-independent active conformations but L858R strictly depends on receptor dimerization, we herein evaluate the therapeutic potential of dimerization-inhibitory monoclonal antibodies (mAbs), including cetuximab. This mAb reduces viability of cells expressing L858R-EGFR and blocks the FOXM1-aurora survival pathway, but other mutants show no responses. Unlike TKI-treated patient-derived xenografts, which relapse post osimertinib treatment, cetuximab completely prevents relapses of L858R+ tumors. We report that osimertinib's inferiority associates with induction of mutagenic reactive oxygen species, whereas cetuximab's superiority is due to downregulation of adaptive survival pathways (e.g., HER2) and avoidance of mutation-prone mechanisms that engage AXL, RAD18, and the proliferating cell nuclear antigen. These results identify L858R as a predictive biomarker, which may pave the way for relapse-free mAb monotherapy relevant to a large fraction of patients with lung cancer.
Subject(s)
ErbB Receptors , Lung Neoplasms , Humans , Cetuximab/pharmacology , Cetuximab/therapeutic use , ErbB Receptors/genetics , Protein Kinase Inhibitors/pharmacology , Neoplasm Recurrence, Local/drug therapy , Lung Neoplasms/drug therapy , Lung Neoplasms/genetics , Lung Neoplasms/pathology , Antibodies, Monoclonal/therapeutic use , Biomarkers , DNA-Binding Proteins , Ubiquitin-Protein LigasesABSTRACT
Multiple studies have identified metabolic changes within the tumor and its microenvironment during carcinogenesis. Yet, the mechanisms by which tumors affect the host metabolism are unclear. We find that systemic inflammation induced by cancer leads to liver infiltration of myeloid cells at early extrahepatic carcinogenesis. The infiltrating immune cells via IL6-pSTAT3 immune-hepatocyte cross-talk cause the depletion of a master metabolic regulator, HNF4α, consequently leading to systemic metabolic changes that promote breast and pancreatic cancer proliferation and a worse outcome. Preserving HNF4α levels maintains liver metabolism and restricts carcinogenesis. Standard liver biochemical tests can identify early metabolic changes and predict patients' outcomes and weight loss. Thus, the tumor induces early metabolic changes in its macroenvironment with diagnostic and potentially therapeutic implications for the host. SIGNIFICANCE: Cancer growth requires a permanent nutrient supply starting from early disease stages. We find that the tumor extends its effect to the host's liver to obtain nutrients and rewires the systemic and tissue-specific metabolism early during carcinogenesis. Preserving liver metabolism restricts tumor growth and improves cancer outcomes. This article is highlighted in the In This Issue feature, p. 1501.
Subject(s)
Liver , Pancreatic Neoplasms , Humans , Liver/metabolism , Carcinogenesis/pathology , Hepatocytes , Pancreatic Neoplasms/pathology , Immunity, Innate , Tumor MicroenvironmentABSTRACT
Decreased intra-tumor heterogeneity (ITH) correlates with increased patient survival and immunotherapy response. However, even highly homogenous tumors may display variability in their aggressiveness, and how immunologic-factors impinge on their aggressiveness remains understudied. Here we studied the mechanisms responsible for the immune-escape of murine tumors with low ITH. We compared the temporal growth of homogeneous, genetically-similar single-cell clones that are rejected vs. those that are not-rejected after transplantation in-vivo using single-cell RNA sequencing and immunophenotyping. Non-rejected clones showed high infiltration of tumor-associated-macrophages (TAMs), lower T-cell infiltration, and increased T-cell exhaustion compared to rejected clones. Comparative analysis of rejection-associated gene expression programs, combined with in-vivo CRISPR knockout screens of candidate mediators, identified Mif (macrophage migration inhibitory factor) as a regulator of immune rejection. Mif knockout led to smaller tumors and reversed non-rejection-associated immune composition, particularly, leading to the reduction of immunosuppressive macrophage infiltration. Finally, we validated these results in melanoma patient data.
ABSTRACT
We found that pediatric glioblastoma (PED-GBM) cell lines from diffuse intrinsic pontine glioma (DIPG) carrying the H3K27M mutation or from diffuse hemispheric glioma expressing the H3G34R mutation are sensitive to the combination of vorinostat (a histone deacetylase inhibitor) and PARP-1 inhibitors. The combined treatment increased the phosphorylation of eIF2α (P-eIF2α) relative to each drug alone and enhanced the decrease in cell survival. To explore the role played by increased P-eIF2α in modulating PED-GBM survival and response to treatments, we employed brain-penetrating inhibitors of P-eIF2α dephosphorylation: salubrinal and raphin-1. These drugs increased P-eIF2α, DNA damage, and cell death, similarly affecting the sensitivity of DIPG cells and derived neurospheres to PARP-1 inhibitors. Interestingly, these drugs also decreased the level of eIF2Bϵ (the catalytic subunit of eIF2B) and increased its phosphorylation, thereby enhancing the effect of increased P-eIF2α. Transient transfection with the S51D phosphomimetic eIF2α variant recapitulated the effect of salubrinal and raphin-1 on PED-GBM survival and sensitivity to PARP-1 inhibitors. Importantly, either salubrinal or raphin-1 dramatically increased the sensitivity of DIPG cells to radiation, the main treatment modality of PED-GBM. Finally, PED-GBM was more sensitive than normal human astrocytes to salubrinal, raphin-1, and the treatment combinations described herein. Our results indicate that combinations of histone deacetylase inhibitors and PARP-1 inhibitors should be evaluated for their toxicity and efficacy in PED-GBM patients and point to drugs that increase P-eIF2α or modulate its downstream effectors as a novel means of treating PED-GBM.
ABSTRACT
Some antibacterial therapies entail sequential treatments with different antibiotics, but whether this approach is optimal for anti-cancer tyrosine kinase inhibitors (TKIs) remains open. EGFR mutations identify lung cancer patients who can derive benefit from TKIs, but most patients develop resistance to the first-, second-, and third-generation drugs. To explore alternatives to such whack-a-mole strategies, we simulated in patient-derived xenograft models the situation of patients receiving first-line TKIs. Monotherapies comprising approved first-line TKIs were compared to combinations with antibodies specific to EGFR and HER2. We observed uniform and strong superiority of all drug combinations over the respective monotherapies. Prolonged treatments, high TKI dose, and specificity were essential for drug-drug cooperation. Blocking pathways essential for mitosis (e.g., FOXM1), along with downregulation of resistance-conferring receptors (e.g., AXL), might underlie drug cooperation. Thus, upfront treatments using combinations of TKIs and antibodies can prevent emergence of resistance and hence might replace the widely applied sequential treatments utilizing next-generation TKIs.
Subject(s)
Carcinoma, Non-Small-Cell Lung , Lung Neoplasms , Carcinoma, Non-Small-Cell Lung/drug therapy , Drug Resistance, Neoplasm , ErbB Receptors/genetics , Humans , Lung Neoplasms/drug therapy , Mutation , Organic Chemicals , Protein Kinase Inhibitors/pharmacology , Protein Kinase Inhibitors/therapeutic useABSTRACT
Angiogenesis and lymphangiogenesis are key processes during embryogenesis as well as under physiological and pathological conditions. Vascular endothelial growth factor C (VEGFC), the ligand for both VEGFR2 and VEGFR3, is a central lymphangiogenic regulator that also drives angiogenesis. Here, we report that members of the highly conserved BACH (BTB and CNC homology) family of transcription factors regulate VEGFC expression, through direct binding to its promoter. Accordingly, down-regulation of bach2a hinders blood vessel formation and impairs lymphatic sprouting in a Vegfc-dependent manner during zebrafish embryonic development. In contrast, BACH1 overexpression enhances intratumoral blood vessel density and peritumoral lymphatic vessel diameter in ovarian and lung mouse tumor models. The effects on the vascular compartment correlate spatially and temporally with BACH1 transcriptional regulation of VEGFC expression. Altogether, our results uncover a novel role for the BACH/VEGFC signaling axis in lymphatic formation during embryogenesis and cancer, providing a novel potential target for therapeutic interventions.
Subject(s)
Basic-Leucine Zipper Transcription Factors/genetics , Fanconi Anemia Complementation Group Proteins/genetics , Neovascularization, Physiologic/physiology , Vascular Endothelial Growth Factor C/genetics , Zebrafish Proteins/genetics , Angiogenesis Modulating Agents/metabolism , Animals , Basic-Leucine Zipper Transcription Factors/metabolism , Cell Line, Tumor , Fanconi Anemia Complementation Group Proteins/metabolism , Female , Gene Expression Regulation, Developmental/genetics , Humans , Lymphangiogenesis/physiology , Lymphatic Vessels/metabolism , Mice , Mice, Inbred C57BL , Mice, Nude , Morphogenesis , Signal Transduction , Vascular Endothelial Growth Factor C/metabolism , Vascular Endothelial Growth Factor Receptor-2/genetics , Vascular Endothelial Growth Factor Receptor-3/genetics , Zebrafish/embryology , Zebrafish Proteins/metabolismABSTRACT
Identifying robust, patient-specific, and predictive biomarkers presents a major obstacle in precision oncology. To optimize patient-specific therapeutic strategies, here we couple pathway knowledge with large-scale drug sensitivity, RNAi, and CRISPR-Cas9 screening data from 460 cell lines. Pathway activity levels are found to be strong predictive biomarkers for the essentiality of 15 proteins, including the essentiality of MAD2L1 in breast cancer patients with high BRCA-pathway activity. We also find strong predictive biomarkers for the sensitivity to 31 compounds, including BCL2 and microtubule inhibitors (MTIs). Lastly, we show that Bcl-xL inhibition can modulate the activity of a predictive biomarker pathway and re-sensitize lung cancer cells and tumors to MTI therapy. Overall, our results support the use of pathways in helping to achieve the goal of precision medicine by uncovering dozens of predictive biomarkers.
Subject(s)
Biomarkers, Tumor/genetics , Gene Expression Profiling , Gene Expression Regulation, Neoplastic , Neoplasms/genetics , Signal Transduction/genetics , Animals , Antineoplastic Agents/pharmacology , BRCA1 Protein/genetics , BRCA1 Protein/metabolism , BRCA2 Protein/genetics , BRCA2 Protein/metabolism , Biomarkers, Tumor/metabolism , Breast Neoplasms/drug therapy , Breast Neoplasms/genetics , Breast Neoplasms/metabolism , Cell Line, Tumor , Female , Gene Regulatory Networks , Humans , Lung Neoplasms/drug therapy , Lung Neoplasms/genetics , Lung Neoplasms/metabolism , Mice , Neoplasms/drug therapy , Neoplasms/metabolism , Precision Medicine/methods , RNA Interference , Signal Transduction/drug effects , Xenograft Model Antitumor Assays/methodsABSTRACT
Although two growth factor receptors, EGFR and HER2, are amongst the best targets for cancer treatment, no agents targeting HER3, their kinase-defective family member, have so far been approved. Because emergence of resistance of lung tumors to EGFR kinase inhibitors (EGFRi) associates with compensatory up-regulation of HER3 and several secreted forms, we anticipated that blocking HER3 would prevent resistance. As demonstrated herein, a neutralizing anti-HER3 antibody we generated can clear HER3 from the cell surface, as well as reduce HER3 cleavage by ADAM10, a surface metalloproteinase. When combined with a kinase inhibitor and an anti-EGFR antibody, the antibody completely blocked patient-derived xenograft models that acquired resistance to EGFRi. We found that the underlying mechanism involves posttranslational downregulation of HER3, suppression of MET and AXL upregulation, as well as concomitant inhibition of AKT signaling and upregulation of BIM, which mediates apoptosis. Thus, although HER3 is nearly devoid of kinase activity, it can still serve as an effective drug target in the context of acquired resistance. Because this study simulated in animals the situation of patients who develop resistance to EGFRi and remain with no obvious treatment options, the observations presented herein may warrant clinical testing.
ABSTRACT
Predicting the outcome of immunotherapy treatment in melanoma patients is challenging. Alterations in genes involved in antigen presentation and the interferon gamma (IFNγ) pathway play an important role in the immune response to tumors. We describe here that the overexpression of PSMB8 and PSMB9, two major components of the immunoproteasome, is predictive of better survival and improved response to immune-checkpoint inhibitors of melanoma patients. We study the mechanism underlying this connection by analyzing the antigenic peptide repertoire of cells that overexpress these subunits using HLA peptidomics. We find a higher response of patient-matched tumor infiltrating lymphocytes against antigens diferentially presented after immunoproteasome overexpression. Importantly, we find that PSMB8 and PSMB9 expression levels are much stronger predictors of melanoma patients' immune response to checkpoint inhibitors than the tumors' mutational burden. These results suggest that PSMB8 and PSMB9 expression levels can serve as important biomarkers for stratifying melanoma patients for immune-checkpoint treatment.
Subject(s)
Melanoma/immunology , Melanoma/therapy , Proteasome Endopeptidase Complex/genetics , Antigen Presentation , Cysteine Endopeptidases/genetics , Cysteine Endopeptidases/immunology , Humans , Immunotherapy , Interferon-gamma/genetics , Interferon-gamma/immunology , Melanoma/diagnosis , Melanoma/genetics , Prognosis , Proteasome Endopeptidase Complex/immunologyABSTRACT
Argininosuccinate synthase (ASS1) downregulation in different tumors has been shown to support cell proliferation and yet, in several common cancer subsets ASS1 expression associates with poor patient prognosis. Here we demonstrate that ASS1 expression under glucose deprivation is induced by c-MYC, providing survival benefit by increasing nitric oxide synthesis and activating the gluconeogenic enzymes pyruvate carboxylase and phosphoenolpyruvate carboxykinase by S-nitrosylation. The resulting increased flux through gluconeogenesis enhances serine, glycine and subsequently purine synthesis. Notably, high ASS1-expressing breast cancer mice do not respond to immune checkpoint inhibitors and patients with breast cancer with high ASS1 have more metastases. We further find that inhibiting purine synthesis increases pyrimidine to purine ratio, elevates expression of the immunoproteasome and significantly enhances the response of autologous primary CD8+ T cells to anti-PD-1. These results suggest that treating patients with high-ASS1 cancers with purine synthesis inhibition is beneficial and may also sensitize them to immune checkpoint inhibition therapy.