Blocking the angiopoietin-2-dependent integrin ß-1 signaling axis abrogates small cell lung cancer invasion and metastasis.

Small cell lung cancer (SCLC) is the most aggressive lung cancer entity with an extremely limited therapeutic outcome. Most patients are diagnosed at an extensive stage. However, the molecular mechanisms driving SCLC invasion and metastasis remain largely elusive. We used an autochthonous SCLC mouse model and matched samples from patients with primary and metastatic SCLC to investigate the molecular characteristics of tumor metastasis. We demonstrate that tumor cell invasion and liver metastasis in SCLC are triggered by an Angiopoietin-2 (ANG-2)/Integrin ß-1-dependent pathway in tumor cells, mediated by focal adhesion kinase/Src kinase signaling. Strikingly, CRISPR-Cas9 KO of Integrin ß-1 or blocking Integrin ß-1 signaling by an anti-ANG-2 treatment abrogates liver metastasis formation in vivo. Interestingly, analysis of a unique collection of matched samples from patients with primary and metastatic SCLC confirmed a strong increase of Integrin ß-1 in liver metastasis in comparison with the primary tumor. We further show that ANG-2 blockade combined with PD-1-targeted by anti-PD-1 treatment displays synergistic treatment effects in SCLC. Together, our data demonstrate a fundamental role of ANG-2/Integrin ß-1 signaling in SCLC cells for tumor cell invasion and liver metastasis and provide a potentially new effective treatment strategy for patients with SCLC.

Clinicopathologic and molecular characteristics of small-scale ROS1-mutant non-small cell lung cancer (NSCLC) patients.

BACKGROUND: ROS1 fusions are well treatable aberrations in NSCLC. Besides solvent-front mutations (SFM) in resistance to targeted therapy, small-scale ROS1 mutations are largely unknown. We exploratively analyzed the clinical and molecular characteristics of small-scale ROS1 mutations in NSCLC patients without activating ROS1 fusions or SFMs. METHODS: Next-generation sequencing was performed on tissue samples from NSCLC patients within the Network Genomic Medicine. Patients with ROS1 fusions and SFMs were excluded. We analyzed clinical characteristics of patients harboring small-scale ROS1-mutations, ROS1- and co-occurring mutations, and their response to systemic therapy. RESULTS: Of 10,396 patients analyzed, 101 (1.0%) patients harbored small-scale ROS1 mutations. Most patients were male (73.3%) and smokers (96.6%). Nearly half of the patients presented with squamous-cell carcinoma (SqCC, 40.4%). Most mutations were transversions (50.5%), and 66% were in the kinase domain. Besides TP53 mutations (65.3%), KRAS (22.8%), EGFR (5.9%), PIK3CA (9.9%) and FGFR1-4 mutations (8.9%) co-occurred. In 10 (9.9%) patients, ROS1 mutation was the only aberration detected. Median overall survival (mOS) differed significantly in patients with or without KRAS co-mutations (9.7 vs 21.5 months, p = 0.02) and in patients treated with or without immune-checkpoint blockade (ICB) during treatment (21.5 vs 4.4 months, p = 0.003). CONCLUSION: The cohort's clinical characteristics contrasted ROS1-fused cohorts. Co-occurrence of KRAS mutations led to shortened survival and patients benefited from ICB. Our data does not support the idea of ROS1 small-scale mutations as strong oncogenic drivers in NSCLC, but rather as relevant bystanders altering the efficacy of treatment approaches.

Somatic rearrangements causing oncogenic ectodomain deletions of FGFR1 in squamous cell lung cancer.

The discovery of frequent 8p11-p12 amplifications in squamous cell lung cancer (SQLC) has fueled hopes that FGFR1, located inside this amplicon, might be a therapeutic target. In a clinical trial, only 11% of patients with 8p11 amplification (detected by FISH) responded to FGFR kinase inhibitor treatment. To understand the mechanism of FGFR1 dependency, we performed deep genomic characterization of 52 SQLCs with 8p11-p12 amplification, including 10 tumors obtained from patients who had been treated with FGFR inhibitors. We discovered somatically altered variants of FGFR1 with deletion of exons 1-8 that resulted from intragenic tail-to-tail rearrangements. These ectodomain-deficient FGFR1 variants (ΔEC-FGFR1) were expressed in the affected tumors and were tumorigenic in both in vitro and in vivo models of lung cancer. Mechanistically, breakage-fusion-bridges were the source of 8p11-p12 amplification, resulting from frequent head-to-head and tail-to-tail rearrangements. Generally, tail-to-tail rearrangements within or in close proximity upstream of FGFR1 were associated with FGFR1 dependency. Thus, the genomic events shaping the architecture of the 8p11-p12 amplicon provide a mechanistic explanation for the emergence of FGFR1-driven SQLC. Specifically, we believe that FGFR1 ectodomain-deficient and FGFR1-centered amplifications caused by tail-to-tail rearrangements are a novel somatic genomic event that might be predictive of therapeutically relevant FGFR1 dependency.

KEAP1/NFE2L2 Pathway Signature Outperforms KEAP1/NFE2L2 Mutation Status and Reveals Alternative Pathway-Activating Mutations in NSCLC.

INTRODUCTION: Activation of the antioxidant KEAP1/NFE2L2 (NRF2) pathway leads to increased glutamine dependence and an aggressive phenotype in NSCLC. Because this pathway has been explored as a clinical target, we developed a transcriptomic signature for identifying KEAP1/NFE2L2-activated tumors. METHODS: A total of 971 NSCLC samples were used to train an expression signature (K1N2-score) to predict KEAP1/NFE2L2 mutations. There were 348 in-house NSCLCs that were analyzed using a NanoString expression panel for validation. RESULTS: The 46-gene K1N2 score robustly predicted KEAP1/NFE2L2 mutations in the validation set irrespective of histology and mutation (area under the curve: 89.5, sensitivity: 90.2%), suggesting that approximately 90% of KEAP1/NFE2L2 mutations are pathway-activating. The K1N2-score outperformed KEAP1/NFE2L2 mutational status when predicting patient survival (score p = 0.047; mutation p = 0.215). In K1N2 score-positive but KEAP1/NFE2L2 wild-type samples, enrichment testing identified SMARCA4/BRG1 and CUL3 mutations as mimics of KEAP1/NFE2L2 mutations. CONCLUSIONS: The K1N2-score identified KEAP1/NFE2L2-activated NSCLC by robustly detecting KEAP1/NFE2L2mut cases and discovering alternative genomic activators. It is a potential means for selecting patients with a constitutively active KEAP1/NFE2L2 pathway.

Characterizing Evolutionary Dynamics Reveals Strategies to Exhaust the Spectrum of Subclonal Resistance in EGFR-Mutant Lung Cancer.

The emergence of resistance to targeted therapies restrains their efficacy. The development of rationally guided drug combinations could overcome this currently insurmountable clinical challenge. However, our limited understanding of the trajectories that drive the outgrowth of resistant clones in cancer cell populations precludes design of drug combinations to forestall resistance. Here, we propose an iterative treatment strategy coupled with genomic profiling and genome-wide CRISPR activation screening to systematically extract and define preexisting resistant subpopulations in an EGFR-driven lung cancer cell line. Integrating these modalities identifies several resistance mechanisms, including activation of YAP/TAZ signaling by WWTR1 amplification, and estimates the associated cellular fitness for mathematical population modeling. These observations led to the development of a combination therapy that eradicated resistant clones in large cancer cell line populations by exhausting the spectrum of genomic resistance mechanisms. However, a small fraction of cancer cells was able to enter a reversible nonproliferative state of drug tolerance. This subpopulation exhibited mesenchymal properties, NRF2 target gene expression, and sensitivity to ferroptotic cell death. Exploiting this induced collateral sensitivity by GPX4 inhibition clears drug-tolerant populations and leads to tumor cell eradication. Overall, this experimental in vitro data and theoretical modeling demonstrate why targeted mono- and dual therapies will likely fail in sufficiently large cancer cell populations to limit long-term efficacy. Our approach is not tied to a particular driver mechanism and can be used to systematically assess and ideally exhaust the resistance landscape for different cancer types to rationally design combination therapies. SIGNIFICANCE: Unraveling the trajectories of preexisting resistant and drug-tolerant persister cells facilitates the rational design of multidrug combination or sequential therapies, presenting an approach to explore for treating EGFR-mutant lung cancer.

Elevated FSP1 protects KRAS-mutated cells from ferroptosis during tumor initiation.

Oncogenic KRAS is the key driver oncogene for several of the most aggressive human cancers. One key feature of oncogenic KRAS expression is an early increase in cellular reactive oxygen species (ROS) which promotes cellular transformation if cells manage to escape cell death, mechanisms of which remain incompletely understood. Here, we identify that expression of oncogenic as compared to WT KRAS in isogenic cellular systems renders cells more resistant to ferroptosis, a recently described type of regulated necrosis. Mechanistically, we find that cells with mutant KRAS show a specific lack of ferroptosis-induced lipid peroxidation. Interestingly, KRAS-mutant cells upregulate expression of ferroptosis suppressor protein 1 (FSP1). Indeed, elevated levels of FSP1 in KRAS-mutant cells are responsible for mediating ferroptosis resistance and FSP1 is upregulated as a consequence of MAPK and NRF2 pathway activation downstream of KRAS. Strikingly, FSP1 activity promotes cellular transformation in soft agar and its overexpression is sufficient to promote spheroid growth in 3D in KRAS WT cells. Moreover, FSP1 expression and its activity in ferroptosis inhibition accelerates tumor onset of KRAS WT cells in the absence of oncogenic KRAS in vivo. Consequently, we find that pharmacological induction of ferroptosis in pancreatic organoids derived from the LsL-KRASG12D expressing mouse model is only effective in combination with FSP1 inhibition. Lastly, FSP1 is upregulated in non-small cell lung cancer (NSCLC), colorectal cancer (CRC) and pancreatic ductal adenocarcinoma (PDAC) as compared to the respective normal tissue of origin and correlates with NRF2 expression in PDAC patient datasets. Based on these data, we propose that KRAS-mutant cells must navigate a ferroptosis checkpoint by upregulating FSP1 during tumor establishment. Consequently, ferroptosis-inducing therapy should be combined with FSP1 inhibitors for efficient therapy of KRAS-mutant cancers.

Tripartite antigen-agnostic combination immunotherapy cures established poorly immunogenic tumors.

BACKGROUND: Single-agent immunotherapy has shown remarkable efficacy in selected cancer entities and individual patients. However, most patients fail to respond. This is likely due to diverse immunosuppressive mechanisms acting in a concerted way to suppress the host anti-tumor immune response. Combination immunotherapy approaches that are effective in such poorly immunogenic tumors mostly rely on precise knowledge of antigenic determinants on tumor cells. Creating an antigen-agnostic combination immunotherapy that is effective in poorly immunogenic tumors for which an antigenic determinant is not known is a major challenge. METHODS: We use multiple cell line and poorly immunogenic syngeneic, autochthonous, and autologous mouse models to evaluate the efficacy of a novel combination immunotherapy named tripartite immunotherapy (TRI-IT). To elucidate TRI-ITs mechanism of action we use immune cell depletions and comprehensive tumor and immune infiltrate characterization by flow cytometry, RNA sequencing and diverse functional assays. RESULTS: We show that combined adoptive cellular therapy (ACT) with lymphokine-activated killer cells, cytokine-induced killer cells, Vγ9Vδ2-T-cells (γδ-T-cells) and T-cells enriched for tumor recognition (CTLs) display synergistic antitumor effects, which are further enhanced by cotreatment with anti-PD1 antibodies. Most strikingly, the full TRI-IT protocol, a combination of this ACT with anti-PD1 antibodies, local immunotherapy of agonists against toll-like receptor 3, 7 and 9 and pre-ACT lymphodepletion, eradicates and induces durable anti-tumor immunity in a variety of poorly immunogenic syngeneic, autochthonous, as well as autologous humanized patient-derived models. Mechanistically, we show that TRI-IT coactivates adaptive cellular and humoral, as well as innate antitumor immune responses to mediate its antitumor effect without inducing off-target toxicity. CONCLUSIONS: Overall, TRI-IT is a novel, highly effective, antigen-agnostic, non-toxic combination immunotherapy. In this study, comprehensive insights into its preclinical efficacy, even in poorly immunogenic tumors, and mode of action are given, so that translation into clinical trials is the next step.

EGFR Inhibition Strongly Modulates the Tumour Immune Microenvironment in EGFR-Driven Non-Small-Cell Lung Cancer.

EGFR-driven non-small-cell lung cancer (NSCLC) patients are currently treated with TKIs targeting EGFR, such as erlotinib or osimertinib. Despite a promising initial response to TKI treatment, most patients gain resistance to oncogene-targeted therapy, and tumours progress. With the development of inhibitors against immune checkpoints, such as PD-1, that mediate an immunosuppressive microenvironment, immunotherapy approaches attempt to restore a proinflammatory immune response in tumours. However, this strategy has shown only limited benefits in EGFR-driven NSCLC. Approaches combining EGFR inhibition with immunotherapy to stimulate the immune response and overcome resistance to therapy have been limited due to insufficient understanding about the effect of EGFR-targeting treatment on the immune cells in the TME. Here, we investigate the impact of EGFR inhibition by erlotinib on the TME and its effect on the antitumour response of the immune cell infiltrate. For this purpose, we used a transgenic conditional mouse model to study the immunological profile in EGFR-driven NSCLC tumours. We found that EGFR inhibition mediated a higher infiltration of immune cells and increased local proliferation of T-cells in the tumours. Moreover, inhibiting EGFR signalling led to increased activation of immune cells in the TME. Most strikingly, combined simultaneous blockade of EGFR and anti-PD-1 (aPD-1) enhanced tumour treatment response in a transgenic mouse model of EGFR-driven NSCLC. Thus, our findings show that EGFR inhibition promotes an active and proinflammatory immune cell infiltrate in the TME while improving response to immune checkpoint inhibitors in EGFR-driven NSCLC.

Normics: Proteomic Normalization by Variance and Data-Inherent Correlation Structure.

Several algorithms for the normalization of proteomic data are currently available, each based on a priori assumptions. Among these is the extent to which differential expression (DE) can be present in the dataset. This factor is usually unknown in explorative biomarker screens. Simultaneously, the increasing depth of proteomic analyses often requires the selection of subsets with a high probability of being DE to obtain meaningful results in downstream bioinformatical analyses. Based on the relationship of technical variation and (true) biological DE of an unknown share of proteins, we propose the "Normics" algorithm: Proteins are ranked based on their expression level-corrected variance and the mean correlation with all other proteins. The latter serves as a novel indicator of the non-DE likelihood of a protein in a given dataset. Subsequent normalization is based on a subset of non-DE proteins only. No a priori information such as batch, clinical, or replicate group is necessary. Simulation data demonstrated robust and superior performance across a wide range of stochastically chosen parameters. Five publicly available spike-in and biologically variant datasets were reliably and quantitively accurately normalized by Normics with improved performance compared to standard variance stabilization as well as median, quantile, and LOESS normalizations. In complex biological datasets Normics correctly determined proteins as being DE that had been cross-validated by an independent transcriptome analysis of the same samples. In both complex datasets Normics identified the most DE proteins. We demonstrate that combining variance analysis and data-inherent correlation structure to identify non-DE proteins improves data normalization. Standard normalization algorithms can be consolidated against high shares of (one-sided) biological regulation. The statistical power of downstream analyses can be increased by focusing on Normics-selected subsets of high DE likelihood.

Insight into Targeting Exon20 Insertion Mutations of the Epidermal Growth Factor Receptor with Wild Type-Sparing Inhibitors.

Despite the clinical efficacy of epidermal growth factor receptor (EGFR) inhibitors, a subset of patients with non-small cell lung cancer displays insertion mutations in exon20 in EGFR and Her2 with limited treatment options. Here, we present the development and characterization of the novel covalent inhibitors LDC8201 and LDC0496 based on a 1H-pyrrolo[2,3-b]pyridine scaffold. They exhibited intense inhibitory potency toward EGFR and Her2 exon20 insertion mutations as well as selectivity over wild type EGFR and within the kinome. Complex crystal structures with the inhibitors and biochemical and cellular on-target activity document their favorable binding characteristics. Ultimately, we observed tumor shrinkage in mice engrafted with patient-derived EGFR-H773_V774insNPH mutant cells during treatment with LDC8201. Together, these results highlight the potential of covalent pyrrolopyridines as inhibitors to target exon20 insertion mutations.

Histone Demethylase KDM5C Drives Prostate Cancer Progression by Promoting EMT.

Prostate cancer (PCa) poses a major public health problem in men. Metastatic PCa is incurable, and ultimately threatens the life of many patients. Mutations in tumor suppressor genes and oncogenes are important for PCa progression, whereas the role of epigenetic factors in prostate carcinogenesis is insufficiently examined. The histone demethylase KDM5C exerts important roles in tumorigenesis. KDM5C has been reported to be highly expressed in various cancer cell types, particularly in primary PCa. Here, we could show that KDM5C is highly upregulated in metastatic PCa. Functionally, in KDM5C knockdown cells migratory and invasion capacity was reduced. Interestingly, modulation of KDM5C expression influences several EMT signaling pathways (e.g., Akt/mTOR), expression of EMT transcription factors, epigenetic modifiers, and miR-205, resulting in increased expression of E-cadherin and reduced expression of N-cadherin. Mouse xenografts of KDM5C knockdown cells showed reduced tumor growth. In addition, the Akt/mTOR pathway is one of the classic signaling pathways to mediate tumor metabolic homeostasis, which is beneficial for tumor growth and metastasis. Taken together, our findings indicate that a combination of a selective KDM5C- and Akt/mTOR-inhibitor might be a new promising therapeutic strategy to reduce metastatic burden in PCa.

CD74-NRG1 Fusions Are Oncogenic In Vivo and Induce Therapeutically Tractable ERBB2:ERBB3 Heterodimerization.

NRG1 fusions are recurrent somatic genome alterations occurring across several tumor types, including invasive mucinous lung adenocarcinomas and pancreatic ductal adenocarcinomas and are potentially actionable genetic alterations in these cancers. We initially discovered CD74-NRG1 as the first NRG1 fusion in lung adenocarcinomas, and many additional fusion partners have since been identified. Here, we present the first CD74-NRG1 transgenic mouse model and provide evidence that ubiquitous expression of the CD74-NRG1 fusion protein in vivo leads to tumor development at high frequency. Furthermore, we show that ERBB2:ERBB3 heterodimerization is a mechanistic event in transformation by CD74-NRG1 binding physically to ERBB3 and that CD74-NRG1-expressing cells proliferate independent of supplemented NRG1 ligand. Thus, NRG1 gene fusions are recurrent driver oncogenes that cause oncogene dependency. Consistent with these findings, patients with NRG1 fusion-positive cancers respond to therapy targeting the ERBB2:ERBB3 receptors.

Inhibition of Cyclin-Dependent Kinase 8/Cyclin-Dependent Kinase 19 Suppresses Its Pro-Oncogenic Effects in Prostate Cancer.

Progression of prostate cancer (PCa) is characterized by metastasis and castration resistance after response to androgen deprivation. Therapeutic options are limited, causing high morbidity and lethality. Recent work reported pro-oncogenic implications of the Mediator subunits cyclin-dependent kinase (CDK) 8 and 19 for the progression of PCa. The current study explored the underlying molecular mechanisms of CDK8/CDK19 and tested effects of novel CDK8/CDK19 inhibitors. PC3, DU145, LNCaP, and androgen-independent LNCaP Abl were used for in vitro experiments. Two inhibitors and CDK19 overexpression were used to modify CDK8/CDK19 activity. MTT assay, propidium iodide staining, wound healing assay, Boyden chamber assay, and adhesion assay were used to investigate cell viability, cell cycle, migration, and adhesion, respectively. Peptide-kinase screen using the PamGene platform was conducted to identify phosphorylated targets. Combining CDK8/CDK19 inhibitors with anti-androgens led to synergistic antiproliferative effects and sensitized androgen-independent cells to bicalutamide. CDK8/CDK19 inhibition resulted in reduced migration and increased collagen I-dependent adhesion. Phosphorylation of multiple peptides linked to cancer progression was identified to be dependent on CDK8/CDK19. In summary, this study substantially supports recent findings on CDK8/CDK19 in PCa progression. These findings contribute to a better understanding of underlying pro-oncogenic effects, which is needed to develop CDK8/CDK19 as a therapeutic target in PCa.

Clonal dynamics of BRAF-driven drug resistance in EGFR-mutant lung cancer.

Activation of MAPK signaling via BRAF mutations may limit the activity of EGFR inhibitors in EGFR-mutant lung cancer patients. However, the impact of BRAF mutations on the selection and fitness of emerging resistant clones during anti-EGFR therapy remains elusive. We tracked the evolution of subclonal mutations by whole-exome sequencing and performed clonal analyses of individual metastases during therapy. Complementary functional analyses of polyclonal EGFR-mutant cell pools showed a dose-dependent enrichment of BRAFV600E and a loss of EGFR inhibitor susceptibility. The clones remain stable and become vulnerable to combined EGFR, RAF, and MEK inhibition. Moreover, only osimertinib/trametinib combination treatment, but not monotherapy with either of these drugs, leads to robust tumor shrinkage in EGFR-driven xenograft models harboring BRAFV600E mutations. These data provide insights into the dynamics of clonal evolution of EGFR-mutant tumors and the therapeutic implications of BRAF co-mutations that may facilitate the development of treatment strategies to improve the prognosis of these patients.

MAPK-pathway inhibition mediates inflammatory reprogramming and sensitizes tumors to targeted activation of innate immunity sensor RIG-I.

Kinase inhibitors suppress the growth of oncogene driven cancer but also enforce the selection of treatment resistant cells that are thought to promote tumor relapse in patients. Here, we report transcriptomic and functional genomics analyses of cells and tumors within their microenvironment across different genotypes that persist during kinase inhibitor treatment. We uncover a conserved, MAPK/IRF1-mediated inflammatory response in tumors that undergo stemness- and senescence-associated reprogramming. In these tumor cells, activation of the innate immunity sensor RIG-I via its agonist IVT4, triggers an interferon and a pro-apoptotic response that synergize with concomitant kinase inhibition. In humanized lung cancer xenografts and a syngeneic Egfr-driven lung cancer model these effects translate into reduction of exhausted CD8+ T cells and robust tumor shrinkage. Overall, the mechanistic understanding of MAPK/IRF1-mediated intratumoral reprogramming may ultimately prolong the efficacy of targeted drugs in genetically defined cancer patients.

CDK19 as a diagnostic marker for high-grade prostatic intraepithelial neoplasia.

High-grade prostatic intraepithelial neoplasia (HGPIN) is a facultative precursor lesion of prostate cancer (PCa). Multifocal HGPIN in needle biopsies in the absence of PCa indicates a higher risk of cancer detection in subsequent biopsies. Therefore, a reliable diagnosis of HGPIN is of high clinical relevance guiding the management of patients with cancer-negative biopsies. Detection of HGPIN is merely based on morphological features while biomarkers aiding in the diagnosis of HGPIN and its differentiation from benign glands and other glandular lesions are lacking yet. Here, we investigated the expression of cyclin-dependent kinase 19 (CDK19) by immunohistochemistry on prostate needle biopsies of 140 patients who were all diagnosed with PCa using whole-tissue sections and compared CDK19 levels between HGPIN, PCa, and adjacent benign glands. In addition, CDK19 was compared with AMACR expression in a subset of intraductal carcinomas (IDCs) on radical prostatectomy (RP) specimens. HGPIN was present in 65.7% of biopsies and in 88% associated to adjacent PCa. CDK19 overexpression defined as moderate to high CDK19 expression visible at low magnification was found in 82.6% of HGPIN. In contrast, 89.3% of benign glands were CDK19-negative or demonstrated only low CDK19 expression highlighting a high sensitivity and specificity to accurately detect HGPIN based on CDK19 expression levels. CDK19 was overexpressed in 59% of PCa but did not correlate significantly with the expression of intermingled HGPIN. On RP, CDK19 and AMACR showed no significant difference in the detection rate of IDC. In summary, assessment of CDK19 facilitates accurate and simplified diagnosis of HGPIN with high sensitivity and specificity and aides the differentiation to non-neoplastic glandular alterations. Considering the high clinical significance of diagnosis HGPIN that still has a limited reproducibility among pathologists, we suggest CDK19 as diagnostic biomarker for HGPIN.

Epigenome-Wide Analysis of Methylation Changes in the Sequence of Gallstone Disease, Dysplasia, and Gallbladder Cancer.

BACKGROUND AND AIMS: Gallbladder cancer (GBC) is a highly aggressive malignancy of the biliary tract. Most cases of GBC are diagnosed in low-income and middle-income countries, and research into this disease has long been limited. In this study we therefore investigate the epigenetic changes along the model of GBC carcinogenesis represented by the sequence gallstone disease → dysplasia → GBC in Chile, the country with the highest incidence of GBC worldwide. APPROACH AND RESULTS: To perform epigenome-wide methylation profiling, genomic DNA extracted from sections of formalin-fixed, paraffin-embedded gallbladder tissue was analyzed using Illumina Infinium MethylationEPIC BeadChips. Preprocessed, quality-controlled data from 82 samples (gallstones n = 32, low-grade dysplasia n = 13, high-grade dysplasia n = 9, GBC n = 28) were available to identify differentially methylated markers, regions, and pathways as well as changes in copy number variations (CNVs). The number and magnitude of epigenetic changes increased with disease development and predominantly involved the hypermethylation of cytosine-guanine dinucleotide islands and gene promoter regions. The methylation of genes implicated in Wnt signaling, Hedgehog signaling, and tumor suppression increased with tumor grade. CNVs also increased with GBC development and affected cyclin-dependent kinase inhibitor 2A, MDM2 proto-oncogene, tumor protein P53, and cyclin D1 genes. Gains in the targetable Erb-B2 receptor tyrosine kinase 2 gene were detected in 14% of GBC samples. CONCLUSIONS: Our results indicate that GBC carcinogenesis comprises three main methylation stages: early (gallstone disease and low-grade dysplasia), intermediate (high-grade dysplasia), and late (GBC). The identified gradual changes in methylation and CNVs may help to enhance our understanding of the mechanisms underlying this aggressive disease and eventually lead to improved treatment and early diagnosis of GBC.

Recurrent HNSCC Harbor an Immunosuppressive Tumor Immune Microenvironment Suggesting Successful Tumor Immune Evasion.

PURPOSE: Recurrent tumors (RT) of head and neck squamous cell carcinoma (HNSCC) occur in up to 60%, with poor therapeutic response and detrimental prognosis. We hypothesized that HNSCC RTs successfully evade antitumor immune response and aimed to reveal tumor immune microenvironment (TIME) changes of primary tumors (PT) and corresponding RTs. EXPERIMENTAL DESIGN: Tumor-infiltrating leukocytes (TIL) of 300 PTs and 108 RTs from two large independent and clinically well-characterized HNSCC cohorts [discovery cohort (DC), validation cohort (VD)] were compared by IHC. mRNA expression analysis of 730 immune-related genes was performed for 18 PTs and RTs after adjuvant chemoradiotherapy (CRT). The effect of chemotherapy and radiation resistance was assessed with an in vitro spheroid/immunocyte coculture model. RESULTS: TIME analysis revealed overall decrease of TILs with significant loss of CD8+ T cells (DC P = 0.045/VC P < 0.0001) and B lymphocytes (DC P = 0.036/VC P < 0.0001) in RTs compared with PTs in both cohorts. Decrease predominantly occurred in RTs after CRT. Gene expression analysis confirmed loss of TILs (P = 0.0004) and B lymphocytes (P < 0.0001) and showed relative increase of neutrophils (P = 0.018), macrophages (P < 0.0001), dendritic cells (P = 0.0002), and mast cells (P = 0.0057) as well as lower overall expression of immune-related genes (P = 0.018) in RTs after CRT. Genes involved in B-lymphocyte functions and number of tertiary lymphoid structures showed the strongest decrease. SPP1 and MAPK1 were upregulated in vivo and in vitro, indicating their potential suitability as therapeutic targets in CRT resistance. CONCLUSIONS: HNSCC RTs have an immunosuppressive TIME, which is particularly apparent after adjuvant CRT and might substantially contribute to poor therapeutic response and prognosis.

CDK19 as a Potential HPV-Independent Biomarker for Recurrent Disease in HNSCC.

The Mediator complex is a central integrator of transcription and a hub for the regulation of gene expression. Cyclin dependent kinase (CDK) 19 and its paralog CDK8 are part of its kinase domain and contribute to cancer progression in different cancer entities. STAT1 is an important immune modulator and a downstream substrate of CDK8/CDK19 mediated phosphorylation. So far, little is known about CDK19's role in head and neck squamous cell carcinoma (HNSCC) progression, its link to STAT1 activity, and related immune modulation. Immunohistochemistry for CDK19, activated pSTAT1, and PD-L1, known to be affected by STAT1, was conducted on samples of 130 primary tumors, 71 local recurrences, 32 lymph node metastases, and 25 distant metastases of HNSCC. Compared to primary tumors, CDK19 is overexpressed in local recurrences and distant metastases as well as in primary tumors that developed local recurrence after initial therapy. Patients with high-CDK19-expressing primary tumors have a significantly shorter disease-free survival. CDK19 expression correlates with pSTAT1 expression in primary tumors associated with recurrent disease, local recurrent tumors, lymph node metastases, and distant metastases. pSTAT1 expression correlates with PD-L1 expression in recurrent tumors. Our findings identify CDK19 as a potential biomarker in HNSCC to predict recurrent disease and support recent developments to target CDK19 and its paralog CDK8 in advanced cancer.