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Abstract Background Aside from the canonical role of PDL1 as a tumour surface-expressed immune checkpoint molecule, tumour-intrinsic PDL1 signals regulate non-canonical immunopathological pathways mediating treatment resistance whose significance, mechanisms, and therapeutic targeting remain incompletely understood. Recent reports implicate tumour-intrinsic PDL1 signals in the DNA damage response (DDR), including promoting homologous recombination DNA damage repair and mRNA stability of DDR proteins, but many mechanistic details remain undefined. Methods We genetically depleted PDL1 from transplantable mouse and human cancer cell lines to understand consequences of tumour-intrinsic PDL1 signals in the DNA damage response. We complemented this work with studies of primary human tumours and inducible mouse tumours. We developed novel approaches to show tumour-intrinsic PDL1 signals in specific subcellular locations. We pharmacologically depleted tumour PDL1 in vivo in mouse models with repurposed FDA-approved drugs for proof-of-concept clinical translation studies. Results We show that tumour-intrinsic PDL1 promotes the checkpoint kinase-2 (Chk2)-mediated DNA damage response. Intracellular but not surface-expressed PDL1 controlled Chk2 protein content post-translationally and independently of PD1 by antagonising PIRH2 E3 ligase-mediated Chk2 polyubiquitination and protein degradation. Genetic tumour PDL1 depletion specifically reduced tumour Chk2 content but not ATM, ATR, or Chk1 DDR proteins, enhanced Chk1 inhibitor (Chk1i) synthetic lethality in vitro in diverse human and murine tumour models, and improved Chk1i efficacy in vivo. Pharmacologic tumour PDL1 depletion with cefepime or ceftazidime replicated genetic tumour PDL1 depletion by reducing tumour Chk2, inducing Chk1i synthetic lethality in a tumour PDL1-dependent manner, and reducing in vivo tumour growth when combined with Chk1i. Conclusions Our data challenge the prevailing surface PDL1 paradigm, elucidate important and previously unappreciated roles for tumour-intrinsic PDL1 in regulating the ATM/Chk2 DNA damage response axis and E3 ligase-mediated protein degradation, suggest tumour PDL1 as a biomarker for Chk1i efficacy, and support the rapid clinical potential of pharmacologic tumour PDL1 depletion to treat selected cancers.

Abstract Metabolic imbalance leading to inflammatory hypoxia and stabilization of hypoxia-inducible transcription factors (HIFs) is a hallmark of inflammatory bowel diseases. We hypothesize that HIF could be stabilized in CD4+ T cells during intestinal inflammation and alter the functional responses of T cells via regulation of microRNAs. Our assays reveal markedly increased T cell-intrinsic hypoxia and stabilization of HIF protein during experimental colitis. microRNA screen in primary CD4+ T cells points us towards miR-29a and our subsequent studies identify a selective role for HIF-2α in CD4-cell-intrinsic induction of miR-29a during hypoxia. Mice with T cell-intrinsic HIF-2α deletion display elevated T-bet (target of miR-29a) levels and exacerbated intestinal inflammation. Mice with miR-29a deficiency in T cells show enhanced intestinal inflammation. T cell-intrinsic overexpression of HIF-2α or delivery of miR-29a mimetic dampen TH1-driven colitis. In this work, we show a previously unrecognized function for hypoxia-dependent induction of miR-29a in attenuating TH1-mediated inflammation.

Abstract Background GP‐2250, a novel analog of taurultam (TRLT), has emerged as a potent anti‐neoplastic drug; however, the mechanisms underlying its effects are not well understood. Here, we investigated the mechanism of action and the biological effects of GP‐2250 using in vitro and in vivo models. Methods We carried out a series of in vitro (MTT assay, Annexin V/PI assay, colony formation assay, reverse‐phase protein array [RPPA], and HRLC/IC analysis) to determine the biological activity of GP‐2250 and investigate the mechanism of action. In vivo experiments were carried out to determine the therapeutic efficacy of GP‐2250 alone and in combination with standard‐of‐care drugs (e.g., paclitaxel, cisplatin, topotecan, and poly ADP‐ribose polymerase [PARP] inhibitors). Results We investigated the cytotoxic effect of GP‐2250 in 10 ovarian cancer cell lines and found GP‐2250 combined with a PARP inhibitor had the greatest synergy. RPPA revealed that GP‐2250 inhibited hypoxia‐inducible factor‐1α, AKT, and mammalian target of rapamycin (mTOR) activation and expression. High‐resolution mass spectrometry revealed that hexokinase2 activity and protein expression were significantly reduced by GP‐2250 exposure. Furthermore, GP‐2250 reduced glycolysis and ATP synthesis in cancer cells. An in vivo pharmacodynamic experiment using the OVCAR8 mouse model demonstrated that 500 mg/kg GP‐2250 was effective in downregulating AKT and mTOR activation and expression. In the in vivo therapy experiment using an orthotopic mouse model, a combination of GP‐2250 with either PARP inhibitors or bevacizumab showed a significant reduction of tumor weights and nodules compared to those treated with a vehicle, control IgG groups, or monotherapy groups. Conclusions Taken together, our data indicate that GP‐2250 exerts profound effects on tumor metabolism and, in combination with PARP inhibitors or bevacizumab, showed promising anti‐tumor efficacy. These findings could have implications for the clinical development of GP‐2250.

Abstract Small RNAs (microRNAs [miRNAs] or small interfering RNAs [siRNAs]) are effective tools for cancer therapy, but many of the existing carriers for their delivery are limited by low bioavailability, insufficient loading, impaired transport across biological barriers, and low delivery into the tumor microenvironment. Extracellular vesicle (EV)–based communication in mammalian and plant systems is important for many physiological and pathological processes, and EVs show promise as carriers for RNA interference molecules. However, some fundamental issues limit their use, such as insufficient cargo loading and low potential for scaling production. Plant-derived vesicles (PDVs) are membrane-coated vesicles released in the apoplastic fluid of plants that contain biomolecules that play a role in several biological mechanisms. Here, we developed an alternative approach to deliver miRNA for cancer therapy using PDVs. We isolated vesicles from watermelon and formulated a hybrid, exosomal, polymeric system in which PDVs were combined with a dendrimer bound to miRNA146 mimic. Third generation PAMAM was chosen due to its high branching structure and versatility for loading molecules of interest. We performed several in vivo experiments to demonstrate the therapeutic efficacy of our compound and explored in vitro biological mechanisms underlying the anti-tumor effects of miRNA146, which are mostly related to its anti-angiogenic activity.

Abstract In this study, we investigated the metabolic alterations associated with clinical response to chemotherapy in patients with ovarian cancer. Pre- and post-neoadjuvant chemotherapy (NACT) tissues from patients with high-grade serous ovarian cancer (HGSC) who had poor response (PR) or excellent response (ER) to NACT were examined. Desorption electrospray ionization mass spectrometry (DESI-MS) was performed on sections of HGSC tissues collected according to a rigorous laparoscopic triage algorithm. Quantitative MS-based proteomics and phosphoproteomics were performed on a subgroup of pre-NACT samples. Highly abundant metabolites in the pre-NACT PR tumors were related to pyrimidine metabolism in the epithelial regions and oxygen-dependent proline hydroxylation of hypoxia-inducible factor alpha in the stromal regions. Metabolites more abundant in the epithelial regions of post-NACT PR tumors were involved in the metabolism of nucleotides, and metabolites more abundant in the stromal regions of post-NACT PR tumors were related to aspartate and asparagine metabolism, phenylalanine and tyrosine metabolism, nucleotide biosynthesis, and the urea cycle. A predictive model built on ions with differential abundances allowed the classification of patients’ tumor responses as ER or PR with 75% accuracy (10-fold cross-validation ridge regression model). These findings offer new insights related to differential responses to chemotherapy and could lead to novel actionable targets.

Abstract Antiangiogenic treatment targeting the vascular endothelial growth factor (VEGF) pathway is a powerful tool to combat tumor growth and progression; however, drug resistance frequently emerges. We identify CD5L (CD5 antigen-like precursor) as an important gene upregulated in response to antiangiogenic therapy leading to the emergence of adaptive resistance. By using both an RNA-aptamer and a monoclonal antibody targeting CD5L, we are able to abate the pro-angiogenic effects of CD5L overexpression in both in vitro and in vivo settings. In addition, we find that increased expression of vascular CD5L in cancer patients is associated with bevacizumab resistance and worse overall survival. These findings implicate CD5L as an important factor in adaptive resistance to antiangiogenic therapy and suggest that modalities to target CD5L have potentially important clinical utility.

Abstract Background Low-grade serous ovarian cancer (LGSOC) is a rare disease that occurs more frequently in younger women than those with high-grade disease. The current treatment is suboptimal and a better understanding of the molecular pathogenesis of this disease is required. In this study, we compared the proteogenomic analyses of LGSOCs from short- and long-term survivors (defined as 60 months, respectively). Our goal was to identify novel mutations, proteins, and mRNA transcripts that are dysregulated in LGSOC, particularly in short-term survivors. Methods Initially, targeted sequencing of 409 cancer-related genes was performed on 22 LGSOC and 6 serous borderline ovarian tumor samples. Subsequently, whole-genome sequencing analysis was performed on 14 LGSOC samples (7 long-term survivors and 7 short-term survivors) with matched normal tissue samples. RNA sequencing (RNA-seq), quantitative proteomics, and phosphoproteomic analyses were also performed. Results We identified single-nucleotide variants (SNVs) (range: 5688–14,833 per sample), insertion and deletion variants (indels) (range: 880–1065), and regions with copy number variants (CNVs) (range: 62–335) among the 14 LGSOC samples. Among all SNVs and indels, 2637 mutation sites were found in the exonic regions. The allele frequencies of the detected variants were low (median12%). The identified recurrent nonsynonymous missense mutations included KRAS, NRAS, EIF1AX, UBR5, and DNM3 mutations. Mutations in DNM3 and UBR5 have not previously been reported in LGSOC. For the two samples, somatic DNM3 nonsynonymous missense mutations in the exonic region were validated using Sanger sequencing. The third sample contained two missense mutations in the intronic region of DNM3, leading to a frameshift mutation detected in RNA transcripts in the RNA-seq data. Among the 14 LGSOC samples, 7754 proteins and 9733 phosphosites were detected by global proteomic analysis. Some of these proteins and signaling pathways, such as BST1, TBXAS1, MPEG1, HBA1, and phosphorylated ASAP1, are potential therapeutic targets. Conclusions This is the first study to use whole-genome sequencing to detect somatic mutations in LGSOCs with matched normal tissues. We detected and validated novel mutations in DNM3, which were present in 3 of the 14 samples analyzed. Additionally, we identified novel indels, regions with CNVs, dysregulated mRNA, dysregulated proteins, and phosphosites that are more prevalent in short-term survivors. This integrated proteogenomic analysis can guide research into the pathogenesis and treatment of LGSOC.

Summary: Despite modest clinical improvement with anti-vascular endothelial growth factor antibody (AVA) therapy in ovarian cancer, adaptive resistance is ubiquitous and additional options are limited. A dependence on glutamine metabolism, via the enzyme glutaminase (GLS), is a known mechanism of adaptive resistance and we aimed to investigate the utility of a GLS inhibitor (GLSi). Our in vitro findings demonstrated increased glutamine abundance and a significant cytotoxic effect in AVA-resistant tumors when GLSi was administered in combination with bevacizumab. In vivo, GLSi led to a reduction in tumor growth as monotherapy and when combined with AVA. Furthermore, GLSi initiated after the emergence of resistance to AVA therapy resulted in a decreased metabolic conversion of pyruvate to lactate as assessed by hyperpolarized magnetic resonance spectroscopy and demonstrated robust antitumor effects with a survival advantage. Given the increasing population of patients receiving AVA therapy, these findings justify further development of GLSi in AVA resistance.

Abstract Background Only 8–23% of advanced epithelial ovarian cancer patients survive for 10 years or longer. Given the need for targeted interventions to improve survival, we interviewed this relatively rare survivor population to gain personalized insights into the reasons for their survival. The aim of this study was to characterize subjective attributions of survival and specific coping mechanisms long-term survivors of ovarian cancer. Methods Twenty-two semi-structured, qualitative interviews assessing survival attributions and coping strategies were conducted from April to November 2014. Data were analyzed in a multistep process using ATLAS.ti.8: codes were identified during review of the transcripts and refined with literature review; the frequency of codes and code co-occurrence was calculated, and codes were grouped into themes. Resulting themes were checked by a national leader of an ovarian cancer advocacy organization and compared against available literature. Results Thematic analysis found that participants credited their long-term survival to a variety of factors including medical, social, religious/spiritual, and lifestyle/personal characteristics. Some participants rejected these same attributions, concluding that the reason for survival was due to luck or unknowable. Several of Carver et al.’s theoretical dimensions of coping were evident in our sample: planning, positive reinterpretation, social support, religion and acceptance whereas three relatively new strategies were uncovered: conserving emotional energy, value-based activity coping, and self-care. Conclusions Long-term survivors’ perspectives were largely consistent with those of newly diagnosed ovarian cancer patients and ovarian cancer survivors of shorter duration. However, the long-term survivors were also willing to reject conventional attributions for survival and recognized the importance of disciplined self-preservational coping strategies.

Abstract To understand the role of polyploid giant cancer cells (PGCCs) in drug resistance and disease relapse, we examined the mRNA expression profile of PGCCs following treatment with paclitaxel in ovarian cancer cells. An acute activation of IL-6 dominated senescence-associated secretory phenotype lasted 2–3 weeks and declined during the termination phase of polyploidy. IL-6 activates embryonic stemness during the initiation of PGCCs and can reprogram normal fibroblasts into cancer-associated fibroblasts (CAFs) via increased collagen synthesis, activation of VEGF expression, and enrichment of CAFs and the GPR77 + /CD10 + fibroblast subpopulation. Blocking the IL-6 feedback loop with tocilizumab or apigenin prevented PGCC formation, attenuated embryonic stemness and the CAF phenotype, and inhibited tumor growth in a patient-derived xenograft high-grade serous ovarian carcinoma model. Thus, IL-6 derived by PGCCs is capable of reprogramming both cancer and stromal cells and contributes to the evolution and remodeling of cancer. Targeting IL-6 in PGCCs may represent a novel approach to combating drug resistance.

Photoacoustic imaging is limited by a lack of contrast agents which can enable combined molecular and physiological imaging at depth. Here the authors address these limitations by developing and validating a contrast agent based on targeted liposomes loaded with J-aggregated indocyanine green dye.

Summary: The extracellular RNA communication consortium (ERCC) is an NIH-funded program aiming to promote the development of new technologies, resources, and knowledge about exRNAs and their carriers. After Phase 1 (2013–2018), Phase 2 of the program (ERCC2, 2019–2023) aims to fill critical gaps in knowledge and technology to enable rigorous and reproducible methods for separation and characterization of both bulk populations of exRNA carriers and single EVs. ERCC2 investigators are also developing new bioinformatic pipelines to promote data integration through the exRNA atlas database. ERCC2 has established several Working Groups (Resource Sharing, Reagent Development, Data Analysis and Coordination, Technology Development, nomenclature, and Scientific Outreach) to promote collaboration between ERCC2 members and the broader scientific community. We expect that ERCC2’s current and future achievements will significantly improve our understanding of exRNA biology and the development of accurate and efficient exRNA-based diagnostic, prognostic, and theranostic biomarker assays.

Abstract Malignant tumor cells exhibit mitochondrial alterations and are also influenced by biobehavioral processes, but the intersection of biobehavioral factors and mitochondria in malignant tumors remains unexplored. Here we examined multiple biochemical and molecular markers of mitochondrial content and function in benign tissue and in high-grade epithelial ovarian carcinoma (EOC) in parallel with exploratory analyses of biobehavioral factors. First, analysis of a publicly-available database (n = 1435) showed that gene expression of specific mitochondrial proteins in EOC is associated with survival. Quantifying multiple biochemical and molecular markers of mitochondrial content and function in tissue from 51 patients with benign ovarian masses and 128 patients with high-grade EOC revealed that compared to benign tissue, EOCs exhibit 3.3–8.4-fold higher mitochondrial content and respiratory chain enzymatic activities (P

Abstract Angiosarcoma is an aggressive malignancy of endothelial cells that carries a high mortality rate. Cytotoxic chemotherapy can elicit clinical responses, but the duration of response is limited. Sequencing reveals multiple mutations in angiogenesis pathways in angiosarcomas, particularly in vascular endothelial growth factor (VEGFR) and mitogen-activated protein kinase (MAPK) signaling. We aimed to determine the biological relevance of these pathways in angiosarcoma. Tissue microarray consisting of clinical formalin-fixed paraffin embedded tissue archival samples were stained for phospho- extracellular signal-regulated kinase (p-ERK) with immunohistochemistry. Angiosarcoma cell lines were treated with the mitogen-activated protein kinase kinase (MEK) inhibitor trametinib, pan-VEGFR inhibitor cediranib, or combined trametinib and cediranib and viability was assessed. Reverse phase protein array (RPPA) was performed to assess multiple oncogenic protein pathways. SVR angiosarcoma cells were grown in vivo and gene expression effects of treatment were assessed with whole exome RNA sequencing. MAPK signaling was found active in over half of clinical angiosarcoma samples. Inhibition of MAPK signaling with the MEK inhibitor trametinib decreased the viability of angiosarcoma cells. Combined inhibition of the VEGF and MAPK pathways with cediranib and trametinib had an additive effect in in vitro models, and a combinatorial effect in an in vivo model. Combined treatment led to smaller tumors than treatment with either agent alone. RNA-seq demonstrated distinct expression signatures between the trametinib treated tumors and those treated with both trametinib and cediranib. These results indicate a clinical study of combined VEGFR and MEK inhibition in angiosarcoma is warranted.

Summary: Bulk and single-cell RNA sequencing do not provide full characterization of tissue spatial diversity in cancer samples, and currently available in situ techniques (multiplex immunohistochemistry and imaging mass cytometry) allow for only limited analysis of a small number of targets. The current study represents the first comprehensive approach to spatial transcriptomics of high-grade serous ovarian carcinoma using intact tumor tissue. We selected a small cohort of patients with highly annotated high-grade serous ovarian carcinoma, categorized them by response to neoadjuvant chemotherapy (poor or excellent), and analyzed pre-treatment tumor tissue specimens. Our study uncovered extensive differences in tumor composition between the poor responders and excellent responders to chemotherapy, related to cell cluster organization and localization. This in-depth characterization of high-grade serous ovarian carcinoma tumor tissue from poor and excellent responders showed that spatial interactions between cell clusters may influence chemo-responsiveness more than cluster composition alone.

Summary: Anti-angiogenic therapies, such as anti-VEGF antibodies (AVAs), have shown promise in clinical settings. However, adaptive resistance to such therapies occurs frequently. We use orthotopic ovarian cancer models with AVA-adaptive resistance to investigate the underlying mechanisms. Genomic profiling of AVA-resistant tumors guides us to endothelial p130cas. We find that bevacizumab induces cleavage of VEGFR2 in endothelial cells by caspase-10 and that VEGFR2 fragments internalize into the nucleus and autophagosomes. Nuclear VEGFR2 and p130cas fragments, together with TNKS1BP1 (tankyrase-1-binding protein), initiate endothelial cell death. Blockade of autophagy in AVA-resistant endothelial cells retains VEGFR2 at the membrane with bevacizumab treatment. Targeting host p130cas with RGD (Arg-Gly-Asp)-tagged nanoparticles or genomic ablation of vascular p130cas in p130casflox/floxTie2Cre mice significantly extends the survival of mice with AVA-resistant ovarian tumors. Higher vascular p130cas is associated with shorter survival of individuals with ovarian cancer. Our findings identify opportunities for new strategies to overcome adaptive resistance to AVA therapy.

Summary: Fragile X-related protein-1 (FXR1) gene is highly amplified in patients with ovarian cancer, and this amplification is associated with increased expression of both FXR1 mRNA and protein. FXR1 expression directly associates with the survival and proliferation of cancer cells. Surface sensing of translation (SUnSET) assay demonstrates that FXR1 enhances the overall translation in cancer cells. Reverse-phase protein array (RPPA) reveals that cMYC is the key target of FXR1. Mechanistically, FXR1 binds to the AU-rich elements (ARE) present within the 3′ untranslated region (3′UTR) of cMYC and stabilizes its expression. In addition, the RGG domain in FXR1 interacts with eIF4A1 and eIF4E proteins. These two interactions of FXR1 result in the circularization of cMYC mRNA and facilitate the recruitment of eukaryotic translation initiation factors to the translation start site. In brief, we uncover a mechanism by which FXR1 promotes cMYC levels in cancer cells.

Abstract Background Gynecologic malignancy is one of the leading causes of mortality in female adults worldwide. Comprehensive genomic analysis has revealed a list of molecular aberrations that are essential to tumorigenesis, progression, and metastasis of gynecologic tumors. However, targeting such alterations has frequently led to treatment failures due to underlying genomic complexity and simultaneous activation of various tumor cell survival pathway molecules. A compilation of molecular characterization of tumors with pharmacological drug response is the next step toward clinical application of patient-tailored treatment regimens. Results Toward this goal, we establish a library of 139 gynecologic tumors including epithelial ovarian cancers (EOCs), cervical, endometrial tumors, and uterine sarcomas that are genomically and/or pharmacologically annotated and explore dynamic pharmacogenomic associations against 37 molecularly targeted drugs. We discover lineage-specific drug sensitivities based on subcategorization of gynecologic tumors and identify TP53 mutation as a molecular determinant that elicits therapeutic response to poly (ADP-Ribose) polymerase (PARP) inhibitor. We further identify transcriptome expression of inhibitor of DNA biding 2 (ID2) as a potential predictive biomarker for treatment response to olaparib. Conclusions Together, our results demonstrate the potential utility of rapid drug screening combined with genomic profiling for precision treatment of gynecologic cancers.

Circular RNAs (circRNAs) are a class of single-stranded closed RNA molecules that are formed by precursor mRNA back-splicing or skipping events of thousands of genes in eukaryotes as covalently closed continuous loops. High-throughput sequencing and bioinformatics approaches have uncovered the broad expression of circRNAs across species. Their high stability, abundance, and evolutionary conservation among species points to their distinct properties and diverse cellular functions as efficient microRNAs and protein sponges; they also play important roles in modulating transcription and splicing. Additionally, most circRNAs are aberrantly expressed in pathological conditions and in a tissue-specific manner such as development and progression of cancer. Herein, we highlight the characteristics, functions, and mechanisms of action of circRNAs in cancer; we also provide an overview of recent progress in the circRNA field and future application of circRNAs as cancer biomarkers and novel therapeutic targets. Keywords: circular RNAs, cancer biomarkers, hallmarks of cancer, exosomes, oncogenic function, platelets, malignant tumors, hematological malignancies, biogenesis, biological functions

Background: Investigations into the function of non-promoter DNA methylation have yielded new insights into the epigenetic regulation of gene expression. However, integrated genome-wide non-promoter DNA methylation and gene expression analyses across a wide number of tumour types and corresponding normal tissues have not been performed. Methods: To investigate the impact of non-promoter DNA methylation on cancer pathogenesis, we performed a large-scale analysis of gene expression and DNA methylation profiles, finding enrichment in the 3’UTR DNA methylation positively correlated with gene expression. Filtering for genes in which 3’UTR DNA methylation strongly correlated with gene expression yielded a list of genes enriched for functions involving T cell activation. Findings: The important immune checkpoint gene Havcr2 showed a substantial increase in 3’UTR DNA methylation upon T cell activation and subsequent upregulation of gene expression in mice. Furthermore, this increase in Havcr2 gene expression was abrogated by treatment with decitabine. Interpretation: These findings indicate that the 3’UTR is a functionally relevant DNA methylation site. Additionally, we show a potential novel mechanism of HAVCR2 regulation in T cells, providing new insights for modulating immune checkpoint blockade. Keywords: 3’UTR, Epigenetics, Immune checkpoint, Methylation

Background: Inflammatory mediator prostaglandin E2–prostaglandin E2 receptor EP3 (PTGER3) signaling is critical for tumor-associated angiogenesis, tumor growth, and chemoresistance. However, the mechanism underlying these effects in ovarian cancer is not known. Methods: An association between higher tumoral expression of PTGER3 and shorter patient survival in the ovarian cancer dataset of The Cancer Genome Atlas prompted investigation of the antitumor effects of PTGER3 downmodulation. PTGER3 mRNA and protein levels were higher in cisplatin-resistant ovarian cancer cells than in their cisplatin-sensitive counterparts. Findings: Silencing of PTGER3 via siRNA in cancer cells was associated with decreased cell growth and less invasiveness, as well as cell-cycle arrest and increased apoptosis, mediated through the Ras-MAPK/Erk-ETS1-ELK1/CFTR1 axis. Furthermore, sustained PTGER3 silencing with multistage vector and liposomal 2’-F-phosphorodithioate-siRNA–mediated silencing of PTGER3 combined with cisplatin resulted in robust antitumor effects in cisplatin-resistant ovarian cancer models. Interpretation: These findings identify PTGER3 as a potential therapeutic target in chemoresistant ovarian cancers expressing high levels of this oncogenic protein. Fund: National Institutes of Health/National Cancer Institute, USA. Keywords: PTGER3, Ovarian cancer, RNA interference, Chemically modified siRNA, Cisplatin resistance, ETS1, ELK1, CFTR

Both platelets and the liver play important roles in the processes of coagulation and innate immunity. Platelet responses at the site of an injury are rapid; their immediate activation and structural changes minimize the loss of blood. The majority of coagulation proteins are produced by the liver—a multifunctional organ that also plays a critical role in many processes: removal of toxins and metabolism of fats, proteins, carbohydrates, and drugs. Chronic inflammation, trauma, or other causes of irreversible damage to the liver can dysregulate these pathways leading to organ and systemic abnormalities. In some cases, platelet-to-lymphocyte ratios can also be a predictor of disease outcome. An example is cirrhosis, which increases the risk of bleeding and prothrombotic events followed by activation of platelets. Along with a triggered coagulation cascade, the platelets increase the risk of pro-thrombotic events and contribute to cancer progression and metastasis. This progression and the resulting tissue destruction is physiologically comparable to a persistent, chronic wound. Various cancers, including colorectal cancer, have been associated with increased thrombocytosis, platelet activation, platelet-storage granule release, and thrombosis; anti-platelet agents can reduce cancer risk and progression. However, in cancer patients with pre-existing liver disease who are undergoing chemotherapy, the risk of thrombotic events becomes challenging to manage due to their inherent risk for bleeding. Chemotherapy, also known to induce damage to the liver, further increases the frequency of thrombotic events. Depending on individual patient risks, these factors acting together can disrupt the fragile balance between pro- and anti-coagulant processes, heightening liver thrombogenesis, and possibly providing a niche for circulating tumor cells to adhere to—thus promoting both liver metastasis and cancer-cell survival following treatment (that is, with minimal residual disease in the liver).

Summary: Enriched tumor epithelium, tumor-associated stroma, and whole tissue were collected by laser microdissection from thin sections across spatially separated levels of ten high-grade serous ovarian carcinomas (HGSOCs) and analyzed by mass spectrometry, reverse phase protein arrays, and RNA sequencing. Unsupervised analyses of protein abundance data revealed independent clustering of an enriched stroma and enriched tumor epithelium, with whole tumor tissue clustering driven by overall tumor “purity.” Comparing these data to previously defined prognostic HGSOC molecular subtypes revealed protein and transcript expression from tumor epithelium correlated with the differentiated subtype, whereas stromal proteins (and transcripts) correlated with the mesenchymal subtype. Protein and transcript abundance in the tumor epithelium and stroma exhibited decreased correlation in samples collected just hundreds of microns apart. These data reveal substantial tumor microenvironment protein heterogeneity that directly bears on prognostic signatures, biomarker discovery, and cancer pathophysiology and underscore the need to enrich cellular subpopulations for expression profiling.

Summary: In patients with high-grade serous ovarian cancer (HGSC), it is unclear which genomic features are related to complete gross resection (R0), which is typically associated with better clinical outcomes, or response to neoadjuvant chemotherapy (NACT). In this study, we evaluated T cell receptor (TCR) repertoire diversity in primary and metastatic tumor samples (n = 90) from clinically well-annotated patients with HGSC who achieved R0 or received NACT with excellent or poor response based on a laparoscopic triage algorithm. TCR sequencing followed by an integrative analysis with comprehensive multi-omics data identified higher TCR diversity (e.g., higher number of unique productive sequences and less clonal relatedness) in the R0 than NACT groups. We found enrichment of specific TCRβ genes usage, distinct mutual exclusiveness and co-occurrence pattern of TCRβ genes among the groups. We also found significantly positive correlations between clonal relatedness and neoantigens, copy number variations, and mutation load in the groups.

Summary: Tumor and stromal interactions consist of reciprocal signaling through cytokines, growth factors, direct cell-cell interactions, and extracellular vesicles (EVs). Small EVs (≤200 nm) have been considered critical messengers of cellular communication during tumor development. Here, we demonstrate that gain-of-function (GOF) p53 protein can be packaged into small EVs and transferred to fibroblasts. GOF p53 protein is selectively bound by heat shock protein 90 (HSP90), a chaperone protein, and packaged into small EVs. Inhibition of HSP90 activity blocks packaging of GOF, but not wild-type, p53 in small EVs. GOF p53-containing small EVs result in their conversion to cancer-associated fibroblasts. In vivo studies reveal that GOF p53-containing small EVs can enhance tumor growth and promote fibroblast transformation into a cancer-associated phenotype. These findings provide a better understanding of the complex interactions between cancer and stromal cells and may have therapeutic implications.

Objective: Venous thromboembolism (VTE) contributes to morbidity and mortality in women with ovarian cancer. Underlying mechanisms of venous thrombosis in ovarian cancer are not well-understood. The aim of this study was to identify the potential role of tissue factor (TF)-bearing extracellular vesicles (EVs) originated from cancer cells in venous thrombosis in ovarian cancer models. Methods: We examined the expression of TF on EVs generated by ovarian cancer cells and the effect of TF-positive EVs on platelet aggregation. Furthermore, we performed TF-knockdown or induced TF-overexpression in ovarian cancer cell lines and examined the effects of EVs obtained from these cells on platelet aggregation. We examined the effect of TF-bearing EVs originated from ovarian cancer cells on venous thrombosis in a mouse model of inferior vena cava (IVC) stenosis. Results: TF was expressed in several ovarian cancer cell lines. EVs derived from ovarian cancer cell lines expressing TF promoted platelet aggregation. TF-knockdown in TF-high CAOV3 and OVCAR8 ovarian cancer cells delayed platelet aggregation induced by their EVs in vitro. Conversely, TF overexpression in TF-low A2780 and HeyA8 cells shortened platelet aggregation time induced by their EVs. EVs from TF-overexpressing A2780 ​cells enhanced thrombosis formation in the IVC stenosis model and resulted in a larger clot burden as compared to EVs from A2780 control cells. Conclusions: TF expression in ovarian cancer cell-derived EVs promoted platelet aggregation and thrombosis in preclinical models. These findings may have implications for reducing VTE rates in women with ovarian cancer.

Summary: Chronic stress-related hormones modulate tumor pathogenesis at multiple levels; however, the molecular pathways involved in stress and cervical cancer progression are not well understood. We established a preclinical orthotopic mouse model of cervical cancer and used the model to show that daily restraint stress increased tumor growth and metastatic tumor burden. Exposure to norepinephrine significantly protected cervical cancer cells from anoikis. We demonstrated that YAP1 was dephosphorylated and translocated from the cytoplasm to the nucleus by norepinephrine, a process initiated by ADRB2/cAMP/protein kinase A activation. Furthermore, anoikis resistance and YAP1 activation induced by norepinephrine could be rescued by a broad β-adrenergic receptor antagonist, propranolol. Collectively, our results provide a pivotal molecular pathway for disrupting pro-tumor neuroendocrine signaling in cervical cancer.

Preeclampsia is a pregnancy-induced condition that impairs the mother’s health and results in pregnancy termination or premature delivery. Elevated levels of placenta-derived extracellular vesicles (pcEV) in the circulation have been consistently associated with preeclampsia, but whether these vesicles induce preeclampsia or are the product of preeclampsia is not known. Guided by a small cohort study of preeclamptic patients, we examined the impact of pcEV on the pathogenesis of preeclampsia in mouse models. We detected pcEV in pregnant C56BL/6J mice with a peak level of 3.8±0.9×107/mL at 17-18 days post-coitum. However, these pregnant mice developed hypertension and proteinuria only after being infused with vesicles purified from injured placenta. These extracellular vesicles released from injured placenta disrupted endothelial integrity and induced vasoconstriction. Enhancing the clearance of extracellular vesicles prevented the development of the extracellular vesicle-induced preeclampsia in mice. Our results demonstrate a causal role of pcEV in preeclampsia and identify microvesicle clearance as a new therapeutic strategy for the treatment of this pregnancy-associated complication.

Background: Circulating miRNAs are known to play important roles in intercellular communication. However, the effects of exosomal miRNAs on cells are not fully understood. Methods: To investigate the role of exosomal miR-1246 in ovarian cancer (OC) microenvironment, we performed RPPA as well as many other in vitro functional assays in ovarian cancer cells (sensitive; HeyA8, Skov3ip1, A2780 and chemoresistant; HeyA8-MDR, Skov3-TR, A2780-CP20). Therapeutic effect of miR-1246 inhibitor treatment was tested in OC animal model. We showed the effect of OC exosomal miR-1246 uptake on macrophages by co-culture experiments. Findings: Substantial expression of oncogenic miR-1246 OC exosomes was found. We showed that Cav1 gene, which is the direct target of miR-1246, is involved in the process of exosomal transfer. A significantly worse overall prognosis were found for OC patients with high miR-1246 and low Cav1 expression based on TCGA data. miR-1246 expression were significantly higher in paclitaxel-resistant OC exosomes than in their sensitive counterparts. Overexpression of Cav1 and anti-miR-1246 treatment significantly sensitized OC cells to paclitaxel. We showed that Cav1 and multi drug resistance (MDR) gene is involved in the process of exosomal transfer. Our proteomic approach also revealed that miR-1246 inhibits Cav1 and acts through PDGFβ receptor at the recipient cells to inhibit cell proliferation. miR-1246 inhibitor treatment in combination with chemotherapy led to reduced tumor burden in vivo. Finally, we demonstrated that when OC cells are co-cultured with macrophages, they are capable of transferring their oncogenic miR-1246 to M2-type macrophages, but not M0-type macrophages. Interpretation: Our results suggest that cancer exosomes may contribute to oncogenesis by manipulating neighboring infiltrating immune cells. This study provide a new mechanistic therapeutic approach to overcome chemoresistance and tumor progression through exosomal miR-1246 in OC patients. Keywords: Exosome, oncomiR, miR-1246, Ovarian cancer, Cav1, P-gp

Osteoclasts mediate bone disruption in a number of degenerative bone diseases. Here, the authors show that miR-182 regulates osteoclastogenesis via PKR and IFN-beta signaling, is correlated with rheumatoid arthritis, and that its ablation or inhibition is protective against bone erosion in mouse models of osteoporosis or inflammatory arthritis.

In ovarian cancer, metastatic phenotype may impact surgical outcomes. Here, the authors show miR-409-3p regulates FABP4 which can increase metastatic potential of ovarian cancer, and treatment with DOPC nanoliposomes containing either miR-409--3p mimic or FABP4 siRNA inhibits tumor progression in mice.

Summary: Although EZH2 enzymatic inhibitors have shown antitumor effects in EZH2-mutated lymphoma and ARID1A-mutated ovarian cancer, many cancers do not respond because EZH2 can promote cancer independently of its histone methyltransferase activity. Here we identify ZRANB1 as the EZH2 deubiquitinase. ZRANB1 binds, deubiquitinates, and stabilizes EZH2. Depletion of ZRANB1 in breast cancer cells results in EZH2 destabilization and growth inhibition. Systemic delivery of ZRANB1 small interfering RNA (siRNA) leads to marked antitumor and antimetastatic effects in preclinical models of triple-negative breast cancer (TNBC). Intriguingly, a small-molecule inhibitor of ZRANB1 destabilizes EZH2 and inhibits the viability of TNBC cells. In patients with breast cancer, ZRANB1 levels correlate with EZH2 levels and poor survival. These findings suggest the therapeutic potential for targeting the EZH2 deubiquitinase ZRANB1. : Many cancer cells are sensitive to depletion of EZH2 but resistant to EZH2 inhibitors, due to EZH2’s enzyme-independent cancer-promoting function. Zhang et al. identify ZRANB1 as an EZH2 deubiquitinase and a potential anticancer target. Keywords: ZRANB1, EZH2, deubiquitinase, breast cancer

Some anticancer drugs target cell microtubules inhibiting mitosis and cell division. Here, the authors show that CRMP2 induces microtubule bundling and that this activity is regulated by the FER kinase, thus providing a rationale for targeting FER in combination with microtubule-targeting drugs.

Summary: Here, we show that HEMATOLOGICAL AND NEUROLOGICAL EXPRESSED 1-LIKE (HN1L) is a targetable breast cancer stem cell (BCSC) gene that is altered in 25% of whole breast cancer and significantly correlated with shorter overall or relapse-free survival in triple-negative breast cancer (TNBC) patients. HN1L silencing reduced the population of BCSCs, inhibited tumor initiation, resensitized chemoresistant tumors to docetaxel, and hindered cancer progression in multiple TNBC cell line-derived xenografts. Additionally, gene signatures associated with HN1L correlated with shorter disease-free survival of TNBC patients. We defined HN1L as a BCSC transcription regulator for genes involved in the LEPR-STAT3 signaling axis as HN1L binds to a putative consensus upstream sequence of STAT3, LEPTIN RECEPTOR, and MIR-150. Our data reveal that BCSCs in TNBC depend on the transcription regulator HN1L for the sustained activation of the LEPR-STAT3 pathway, which makes it a potentially important target for both prognosis and BCSC therapy.

Angiogenesis plays an essential role in the growth and metastasis of tumor cells, and the modulation of angiogenesis can be an effective approach for cancer therapy. We focused on silencing the angiogenic gene PLXDC1 as an important factor for anti-angiogenesis tumor therapy. Herein, we developed PLXDC1 small interfering siRNA (siRNA)-incorporated chitosan nanoparticle (CH-NP/siRNA) coated with hyaluronic acid (HA) to target the CD44 receptor on tumor endothelial cells. This study aimed to improve targeted delivery and enhance therapeutic efficacy for tumor anti-angiogenesis. The HA-CH-NP/siRNA was 200 ± 10 nm in size with a zeta potential of 26.4 mV. The loading efficiency of siRNA to the HA-CH-NP/siRNA was up to 60%. The selective binding of HA-CH-NP/siRNA to CD44-positive tumor endothelial cells increased by 2.1-fold compared with that of the CD44 nontargeted CH-NP/siRNA. PLXDC1 silencing by the HA-CH-NP/siRNA significantly inhibited tumor growth in A2780 tumor-bearing mice compared with that in the control group (p