Tumor Niche Research Articles

Transcriptome Analysis of Lymphoma Edited Monocyte Phenotype

Background: Immune editing is a major mechanism used by tumors to promote its survival. Checkpoint inhibitors demonstrated clinical utilities of targeting tumor-mediated immune suppression. We aim to identify additional immunotherapy targets for myeloid cells and previously reported the presence of a novel phenotype of immunosuppressive monocytes (CD14+HLA-DRlow/neg) in a number of cancers. Increased presence of these cells was associated with decreased treatment response and OS. We have demonstrated that certain tumor cells can convert normal CD14+HLA-DR+ monocytes to CD14+HLA-DRlow/neg phenotype in an IL10 independent and a tumor specific way. These CD14+HLA-DRlow/neg monocytes, in turn, protect tumors from chemotherapy. Here we examine transcriptome changes from lymphoma editing of monocyte as a more comprehensive examination of these cells to inform development of therapeutic strategies.Method: Monocytes from healthy donors were co-cultured alone or with lymphoma cell lines (OCI-Ly3, n=3; Jeko-1, n=3; Granta-519, n=6; monocytes from healthy donors n=8 and lymphoma patients n=2). Cultured cells were isolated with immunomagnetic beads, assessed for phenotype by flow cytometry before RNAseq. Change in log expression level was analyzed using a linear mixed model with donor as the random effect to account for correlations between expression levels of different samples from the same donor.Results: RNA reads from both normal monocytes and lymphoma-converted CD14+HLA-DRlow/neg cells revealed that nearly half of the genes (n=11,611, 51.5%) are expressed at levels > 0.3 RPKM (kilo-base pair per 106 mapped reads). About 20.4% of these genes changed by more than 2-fold when after monocytes were co-culture with lymphoma cells (n=1184 up-regulated, n=1186 down-regulated). Gene ontology (GO) enrichment analysis by FunRich showed that top biological processes in the up-regulated genes are in plasma membranes (37.6%, p=1.3E-19) and integrin family cell surface interactions (33.1%, p=3.9E-7), and that the down-regulated genes are lysosome (22.0%, p=4.0E-23) and exosomes activities (23.4%, p=4.0E-16). For the top 100 up regulated genes with the highest RNA expressions in the lymphoma converted monocytes, protein interaction network analysis by STRING showed highly interactive nodes around IL8, CCR2, ALDOA, and VEGFA. For the top 100 genes with high monocyte expressions that were down regulated in co-culture, highest nodal interactions were seen with HLA-DP and HSP8. Interestingly, 25.3% of genes up-regulated and 26% of genes down regulated were shared among co-culture with at least two of the three cell lines. Among the shared genes, 32.1% of the up-regulated genes were involved in integrin family cell interactions; and 16.4% of the down-regulated genes were involved in STAT4-mediated IL12 signaling, immune regulation between lymphoid and non-lymphoid cell, and adaptive immune response. Monocytes from two lymphoma patients showed that up to 17.1% (84/490) of the up-regulated and close to 4.6% (34/741) of the down-regulated genes in primary lymphoma patients' monocytes were the same as those found from the in vitro generated CD14+HLA-DRlow/neg cells.Conclusions: We have shown that RNAseq is informative to understand the biological roles of immunosuppressive monocytes on lymphoma cells in a co-culture model. Preliminary analysis confirmed known phenotype changes in these cells and identified additional novel affected pathways by which monocytes support the oncogenic fitness of lymphoma cells in the tumor niche. Mechanistic studies of the newly identified pathways and functional analyses of affected pathways in primary monocytes from additional lymphoma patients are in progress. DisclosuresNo relevant conflicts of interest to declare.

Simultaneous blockage of contextual TGF-β by cyto-pharmaceuticals to suppress breast cancer metastasis

It remains challenging to treat tumor metastasis currently in the light of multiple cascade processes of tumor metastasis. Additionally, multiple clinical drugs for metastasis have quite limited therapeutic potential and even facilitate metastasis in preclinical models. Thus, potential metastasis targets and novel metastasis-directed drugs are urgently needed to be further developed. Herein, transforming growth factor-β (TGF-β) is verified to contribute to lung metastasis in a context-dependent manner in the 4T1 orthotopic tumor-bearing mice model, which induces epithelial-mesenchymal-transition (EMT) to promote tumor dissemination from the primary site and dampens the anti-tumor response of neutrophils to support tumor colonization at the metastatic niche. In view of neutrophils' superior tropism towards both inflammatory primary tumor and metastatic niche, SB525334, a TGF-β receptor inhibitor, is loaded into cationic liposome (SBLP) which is subsequently incorporated into neutrophils to yield the cyto-pharmaceuticals (SBLP/NE). The systemically infused SBLP/NE can simultaneously migrate into both primary and metastatic sites, then release SB525334 in response to tumor stimuli, and contextually inhibit TGF-β-mediated-EMT and phenotype reversal of infiltrated neutrophils, showing substantial metastasis suppression efficacy without causing any detectable toxicities. This project shifts the paradigm for metastasis suppression therapy by simultaneous blockage of contextual TGF-β using metastatic-cascades-targeting neutrophil cyto-pharmaceuticals.

Visceral Obesity Promotes Lung Cancer Progression—Toward Resolution of the Obesity Paradox in Lung Cancer

IntroductionAlthough obesity is associated with adverse cancer outcomes in general, most retrospective clinical studies suggest a beneficial effect of obesity in NSCLC. MethodsHypothesizing that this “obesity paradox” arises partly from the limitations of using body mass index (BMI) to measure obesity, we quantified adiposity using preoperative computed tomography images. This allowed the specific determination of central obesity as abdominal visceral fat area normalized to total fat area (visceral fat index [VFI]). In addition, owing to the previously reported salutary effect of metformin on high-BMI patients with lung cancer, metformin users were excluded. We then explored associations between visceral obesity and outcomes after surgical resection of stage I and II NSCLC. We also explored potential immunologic underpinnings of such association using complimentary analyses of tumor gene expression data from NSCLC tumors and the tumor transcriptome and immune microenvironment in an immunocompetent model of lung cancer with diet-induced obesity. ResultsWe found that in 513 patients with stage I and II NSCLC undergoing lobectomy, a high VFI is associated with decreased recurrence-free and overall survival. VFI was also inversely related to an inflammatory transcriptomic signature in NSCLC tumors, consistent with observations made in immunocompetent murine models wherein diet-induced obesity promoted cancer progression while exacerbating elements of immune suppression in the tumor niche. ConclusionsIn all, this study uses multiple lines of evidence to reveal the adverse effects of visceral obesity in patients with NSCLC, which align with those found in animal models. Thus, the obesity paradox may, at least in part, be secondary to the use of BMI as a measure of obesity and the confounding effects of metformin use.

In Vitro Glioblastoma Models: A Journey into the Third Dimension.

Simple SummaryIn this review, the thorny issue of glioblastoma models is addressed, with a focus on 3D in vitro models. In the first part of the manuscript, glioblastoma features and classification are recapitulated, in order to highlight the major critical aspects that should be taken into account when choosing a glioblastoma 3D model. In the second part of the review, the 3D models described in the literature are critically discussed, considering the advantages, disadvantages, and feasibility for each experimental model, in the light of the potential issues that researchers want to address.Glioblastoma multiforme (GBM) is the most lethal primary brain tumor in adults, with an average survival time of about one year from initial diagnosis. In the attempt to overcome the complexity and drawbacks associated with in vivo GBM models, together with the need of developing systems dedicated to screen new potential drugs, considerable efforts have been devoted to the implementation of reliable and affordable in vitro GBM models. Recent findings on GBM molecular features, revealing a high heterogeneity between GBM cells and also between other non-tumor cells belonging to the tumoral niche, have stressed the limitations of the classical 2D cell culture systems. Recently, several novel and innovative 3D cell cultures models for GBM have been proposed and implemented. In this review, we first describe the different populations and their functional role of GBM and niche non-tumor cells that could be used in 3D models. An overview of the current available 3D in vitro systems for modeling GBM, together with their major weaknesses and strengths, is presented. Lastly, we discuss the impact of groundbreaking technologies, such as bioprinting and multi-omics single cell analysis, on the future implementation of 3D in vitro GBM models.

Expansion of Rare Cancer Cells into Tumoroids for Therapeutic Regimen and Cancer Therapy

AbstractRare cancer cells, such as circulating tumor cells (CTCs) and cancer stem cells (CSCs), are small cell population found in cancer patients. CTCs have been recognized as tumor avatars for real‐time cancer monitoring, while CSCs are the most malignant tumor cells that play a dominant role in drug resistance and metastasis. Interestingly, these two types of cells share the same surface markers, such as EpCAM, CD44, and CD133. While capturing these rare cells is available, the expansion of these cells is still challenging due to the limited cell number. These cells are susceptible to the microenvironment and lose the capability to grow in vitro, especially after an intense capturing process. A technology called patient‐derived tumor organoids (PDOs) or tumoroids is a rising start in cancer modeling but the applicability is still questionable. Recently, assembloids containing multiple tumor‐related cells have been developed which is one step closer to the real tumor. In this review, strategies for in vitro expansion of tumoroids are summarized implying that artificial tumor niche composed of optimized biophysical and biological cues is vital in the tumoroid generation. Tumoroids containing rare cancer cells is believed to be beneficial in the diagnosis, therapeutic regimen, and drug discovery for personalized therapy.

A Heterotypic Tridimensional Model to Study the Interaction of Macrophages and Glioblastoma In Vitro.

Background: Glioblastoma multiforme (GBM) is the most frequent and aggressive primary brain tumor, and macrophages account for 30–40% of its composition. Most of these macrophages derive from bone marrow monocytes playing a crucial role in tumor progression. Unraveling the mechanisms of macrophages-GBM crosstalk in an appropriate model will contribute to the development of specific and more successful therapies. We investigated the interaction of U87MG human GBM cells with primary human CD14+ monocytes or the THP-1 cell line with the aim of establishing a physiologically relevant heterotypic culture model. Methods: primary monocytes and THP-1 cells were cultured in the presence of U87MG conditioned media or co-cultured together with previously formed GBM spheroids. Monocyte differentiation was determined by flow cytometry. Results: primary monocytes differentiate to M2 macrophages when incubated with U87MG conditioned media in 2-dimensional culture, as determined by the increased percentage of CD14+CD206+ and CD64+CD206+ populations in CD11b+ cells. Moreover, the mitochondrial protein p32/gC1qR is expressed in monocytes exposed to U87MG conditioned media. When primary CD14+ monocytes or THP-1 cells are added to previously formed GBM spheroids, both invade and establish within them. However, only primary monocytes differentiate and acquire a clear M2 phenotype characterized by the upregulation of CD206, CD163, and MERTK surface markers on the CD11b+CD14+ population and induce alterations in the sphericity of the cell cultures. Conclusion: our results present a new physiologically relevant model to study GBM/macrophage interactions in a human setting and suggest that both soluble GBM factors, as well as cell-contact dependent signals, are strong inducers of anti-inflammatory macrophages within the tumor niche.

Sleep disorders and prostate cancer prognosis: biology, epidemiology, and association with cancer development risk.

Sleep is crucial for the maintenance of health and well-being. Sleep disorders can result in physiological consequences and are associated with several health issues, including cancer. Cancer is one of the most significant health problems in the world. In Western countries, prostate cancer is the most prevalent noncutaneous cancer among men. Epidemiological studies showed that one in nine men will have this disease during their life. Many factors influence prostate cancer and the tumor niche, including endogenous hormones, family history, diet, and gene mutations. Disruption of the circadian cycle by sleep disorders or other factors has been suggested as a novel and important risk factor for prostate cancer and its tumorigenesis. This review presents information regarding the epidemiological and biological aspects of prostate cancer, and discusses the impact of sleep physiology and sleep disorders on this type of cancer, highlighting possible associations with risk of cancer development.

532 Keratinocyte desmoglein 1 as a target and mediator of paracrine signaling in the melanoma niche

The melanoma microenvironment is important for tumor progression, but the role of neighboring keratinocytes (KC) in the tumor niche remains poorly understood. We previously showed that loss of the KC-specific desmosomal cadherin, desmoglein 1 (Dsg1), results in release of KC cytokines to alter melanocyte pigmentation and dendricity. This led us to address whether KC Dsg1 plays a role in the melanoma microenvironment. Here, we show that Dsg1 is reduced in regions surrounding melanoma lesions but is unchanged in KCs adjacent to benign nevi. To address whether melanoma cells contribute to Dsg1 loss, we cultured KCs in melanoma cell conditioned media and measured Dsg1 protein and mRNA levels. Melanoma cell, but not melanocyte, conditioned media reduced KC Dsg1 expression downstream of decreased Grhl1, a transcriptional activator of Dsg1. As we showed that Dsg1 loss stimulates expression of pro-migratory cytokines, we carried out transwell assays to compare behavior of melanoma cells treated with conditioned media from control, Dsg1-deficient and Dsg1-deficient KCs rescued with exogenous Dsg1. Media from Dsg1-deficient KCs increased melanoma cell migration compared to media from control KCs or KCs with Dsg1 rescue. Consistent with these data, staining of melanoma tumors revealed a negative correlation between KC Dsg1 expression and melanoma cell movement in the tumor niche. ERK1/2-dependent expression of CXCL1 increased in KCs exposed to melanoma cell conditioned media downstream of Dsg1 loss, and inhibition of the CXCL1 receptor CXCR2 abrogated Dsg1 loss driven melanoma cell migration, confirming the contribution of KC CXCL1 to the observed cell migration. Taken together, these data point to Dsg1 loss as a key regulator KC-melanoma cell cross talk in the tumor niche and a possible contributor to melanoma progression.

Combined Effects of Myeloid Cells in the Neuroblastoma Tumor Microenvironment.

Simple SummaryNeuroblastoma is a type of childhood solid cancer often characterized by resistance to treatment and with poor prognosis. The tumors contain a mixture of cell types as well as cancer cells, and one of the most common is a type of blood cells called myeloid cells. In this review article we present a summary of what is known about the function of myeloid cells within neuroblastoma tumors.Despite multimodal treatment, survival chances for high-risk neuroblastoma patients remain poor. Immunotherapeutic approaches focusing on the activation and/or modification of host immunity for eliminating tumor cells, such as chimeric antigen receptor (CAR) T cells, are currently in development, however clinical trials have failed to reproduce the preclinical results. The tumor microenvironment is emerging as a major contributor to immune suppression and tumor evasion in solid cancers and thus has to be overcome for therapies relying on a functional immune response. Among the cellular components of the neuroblastoma tumor microenvironment, suppressive myeloid cells have been described as key players in inhibition of antitumor immune responses and have been shown to positively correlate with more aggressive disease, resistance to treatments, and overall poor prognosis. This review article summarizes how neuroblastoma-driven inflammation induces suppressive myeloid cells in the tumor microenvironment and how they in turn sustain the tumor niche through suppressor functions, such as nutrient depletion and generation of oxidative stress. Numerous preclinical studies have suggested a range of drug and cellular therapy approaches to overcome myeloid-derived suppression in neuroblastoma that warrant evaluation in future clinical studies.

Role of Osteocytes in Cancer Progression in the Bone and the Associated Skeletal Disease.

The goal of this manuscript is to review the current knowledge on the role of osteocytes in cancer in the bone, discuss the potential of osteocytes as a therapeutic target, and propose future research needed to understand the crosstalk between cancer cells and osteocytes in the tumor niche. Numerous studies have established that cancer cells manipulate osteocytes to facilitate invasion and tumor progression in bone. Moreover, cancer cells dysregulate osteocyte function to disrupt physiological bone remodeling, leading to the development of bone disease. Targeting osteocytes and their derived factors has proven to effectively interfere with the progression of cancer in the bone and the associated bone disease. Osteocytes communicate with cancer cells and are also part of the vicious cycle of cancer in the bone. Additional studies investigating the role of osteocytes on metastases to the bone and the development of drug resistance are needed.

FSMP-14. METABOLIC SYMBIOSIS IN GLIOBLASTOMA: LACTATE DEHYDROGENASES TAKE THE LEAD

Glioblastoma (GBM) is a common and devastating brain tumor, associated with a low median survival, despite standard therapeutic management. Among its major features, GBMs are highly angiogenic, infiltrative, and exhibit paradoxically an elevated glycolysis. Most of differentiated cells convert glucose into pyruvate that enters into the Krebs cycle to maximize energy production in the presence of oxygen. For cancer cells, glucose uptake and catabolism are increased regardless of oxygen level. However, tumor cell energy needs are important, mainly for rapid growth, which require a much faster production flow. Lactate dehydrogenase (LDH) are involved at this step. LDHA converts pyruvate into lactate, and generates NAD+ to maintain glycolysis. Thus, lactate is exported into the extracellular compartment inducing an acidification of the microenvironment. Moreover, LDHB, another LDH isoform, metabolizes lactate into pyruvate for generating energy in mitochondria. LDHB is generally expressed in oligodendrocytes or neurons, but also in GBM cells. Though LDHA has already been studied in many cancers including GBM, the simultaneous role of LDH enzymes have not yet been investigated in GBM development. Our results showed that hypoxia significantly increased LDHA expression and lactate production, but no changes were observed for LDHB. In presence of lactate, cell invasion was significantly increased. In vitro results showed that, under hypoxic condition, double sgLDHA/B cell growth and invasion was dramatically decreased in comparison to control cells, mainly caused by an increase in apoptosis. In vivo experiments showed that double impairment of LDHA and B significantly reduced tumor growth and cell invasion, and induces a massive increase in mouse survival. Considered for a long time as a metabolic waste, lactate is shown here to play a critical role in the tumor niche. This study highlighted GBM adaptability through the LDH isoforms and their involvement in GBM development.

The Multifaceted Role of Th1, Th9, and Th17 Cells in Immune Checkpoint Inhibition Therapy.

During the last decade, immune checkpoint inhibition (ICI) has become a pillar of cancer therapy. Antibodies targeting CTLA-4 or PD-1/PD-L1 have been approved in several malignancies, with thousands of clinical trials currently underway. While the majority of cancer immunotherapies have traditionally focused on enhancing cytotoxic responses by CD8+ or NK cells, there are clear evidences that CD4+ T cell responses can modulate the immune response against tumors and influence the efficacy of ICI therapy. CD4+ T cells can differentiate into several subsets of helper T cells (Th) or regulatory T cells (Treg), with a wide range of effector and/or regulatory functions. Importantly, different Th subsets may have different and sometimes contrasting roles in the clinical response to ICI therapy, which in addition may vary depending on the organ and tumor niche. In this review, we discuss recent evidence that highlights how ICI therapy impacts Th1, Th9, and Th17 cells and vice versa. These data might be important designing better interventions that unleash the full potential of immune response against cancer.

Targeting KRAS: The Elephant in the Room of Epithelial Cancers.

Mutations of the proto-oncogene KRAS are the most frequent gain-of-function alterations found in cancer. KRAS is mutated in about 30% of all human tumors, but it could reach more than 90% in certain cancer types such as pancreatic adenocarcinoma. Although historically considered to be undruggable, a particular KRAS mutation, the G12C variant, has recently emerged as an actionable alteration especially in non-small cell lung cancer (NSCLC). KRASG12C and pan-KRAS inhibitors are being tested in clinical trials and have recently shown promising activity. Due to the difficulties in direct targeting of KRAS, other approaches are being explored. The inhibition of target upstream activators or downstream effectors of KRAS pathway has shown to be moderately effective given the evidence of emerging mechanisms of resistance. Various synthetic lethal partners of KRAS have recently being identified and the inhibition of some of those might prove to be successful in the future. The study of escape mechanisms to KRAS inhibition could support the utility of combination strategies in overcoming intrinsic and adaptive resistance and enhancing clinical benefit of KRASG12C inhibitors. Considering the role of the microenvironment in influencing tumor initiation and promotion, the immune tumor niche of KRAS mutant tumors has been deeply explored and characterized for its unique immunosuppressive skewing. However, a number of aspects remains to be fully understood, and modulating this tumor niche might revert the immunoresistance of KRAS mutant tumors. Synergistic associations of KRASG12C and immune checkpoint inhibitors are being tested.

Cancer Stem Cells: Significance in Origin, Pathogenesis and Treatment of Glioblastoma.

Cancer stem cells (CSCs), known also as tumor-initiating cells, are quiescent, pluripotent, self-renewing neoplastic cells that were first identified in hematologic tumors and soon after in solid malignancies. CSCs have attracted remarkable research interest due to their role in tumor resistance to chemotherapy and radiation treatment as well as recurrence. Extensive research has been devoted to the role of CSCs in glioblastoma multiforme (GBM), the most common primary brain tumor in adults, which is characterized by a dismal prognosis because of its aggressive course and poor response to treatment. The aim of the current paper is to provide an overview of current knowledge on the role of cancer stem cells in the pathogenesis and treatment resistance of glioblastoma. The six regulatory mechanisms of glioma stem cells (GSCs)—tumor microenvironment, niche concept, metabolism, immunity, genetics, and epigenetics—are reviewed. The molecular markers used to identify GSCs are described. The role of GSCs in the treatment resistance of glioblastoma is reviewed, along with future treatment options targeting GSCs. Stem cells of glioblastoma thus represent both a driving mechanism of major treatment difficulties and a possible target for more effective future approaches.

Thymoquinone inhibited vasculogenic capacity and promoted mesenchymal-epithelial transition of human breast cancer stem cells

BackgroundVasculogenic mimicry (VM) is characterized by the formation of tubular structure inside the tumor stroma. It has been shown that a small fraction of cancer cells, namely cancer stem cells (CSCs), could stimulate the development of vascular units in the tumor niche, leading to enhanced metastasis to the remote sites. This study aimed to study the inhibitory effect of phytocompound, Thymoquinone (TQ), on human breast MDA-MB-231 cell line via monitoring Wnt/PI3K signaling pathway.MethodsMDA-MB-231 CSCs were incubated with different concentrations of TQ for 48 h. The viability of CSCs was determined using the MTT assay. The combination of TQ and PI3K and Wnt3a inhibitors was examined in CSCs. By using the Matrigel assay, we measured the tubulogenesis capacity. The percent of CD24− CSCs and Rhodamine 123 efflux capacity was studied using flow cytometry analysis. Protein levels of Akt, p-Akt, Wnt3a, vascular endothelial-cadherin (VE-cadherin), and matrix metalloproteinases-2 and -9 (MMP-2 and -9) were detected by western blotting.ResultsTQ decreased the viability of CSCs in a dose-dependent manner. The combination of TQ with PI3K and Wnt3a inhibitors reduced significantly the survival rate compared to the control group (p < 0.05). TQ could blunt the stimulatory effect of vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), fibroblast growth factor (FGF) on CSCs (p < 0.05). The vasculogenic capacity of CSCs was reduced after being-exposed to TQ (p < 0.05). Western blotting revealed the decrease of CSCs metastasis by suppressing MMP-2 and -9. The protein level of VE-cadherin was also diminished in TQ-treated CSCs as compared to the control cell (p < 0.05), indicating inhibition of mesenchymal-endothelial transition (MendT). TQ could suppress Wnt3a and PI3K, which coincided with the reduction of the p-Akt/Akt ratio. TQ had the potential to decrease the number of CD24− CSCs and Rhodamine 123 efflux capacity after 48 h.ConclusionTQ could alter the vasculogenic capacity and mesenchymal-epithelial transition of human breast CSCs in vitro. Thus TQ together with anti-angiogenic therapies may be a novel therapeutic agent in the suppression of VM in breast cancer.

The prospects of nanotherapeutic approaches for targeting tumor-associated macrophages in oral cancer

OSCC (oral squamous cell carcinoma) is currently one of the most formidable cancers plagued by challenges like low overall survivability, lymph node associated metastasis, drug resistance, and poor diagnostics. The tumor microenvironment (TME) and its constituent stromal elements are crucial modulators of tumor growth and treatment response, more specifically so with regards to resident tumor associated macrophages (TAMs) and their liaison with the different stromal elements in the tumor niche (Figure 1). Interestingly, there isn’t much information on TAM-targeted nanotherapy in OSCC where the first line of therapeutics for oral cancer is surgery with other therapeutics such as chemo- and radiotherapy acting only as adjuvant therapy for oral cancer. In the face of this real time situation, there have been some successful attempts at targeted therapy for OSCC cells and we believe they might elicit favorable responses against TAMs as well. Demanding our immediate attention, this review intends to provide a glimpse of the prevailing anti-TAM treatment strategies, which present great prospect for an uncharted territory like OSCC.

Abstract PO007: Role of PI3K pathway in reprogramming the tumor niche of angiosarcoma

Abstract Angiosarcoma (AS) is a highly aggressive, rare soft-tissue sarcoma that forms malignant blood vessels. Approximately half of patients have metastatic or unresectable disease with a median overall survival of less than 6 months, and tumor-related mortality is high. Inflamed tissue is frequently seen in angiosarcomas, and immune cells are key components that contribute to the landscape of the tumor microenvironment. Hemangiosarcoma (HSA) occurs commonly in companion dogs, and it shares clinical and morphological features with human AS. Recurrent mutations in TP53 and genes involved in PI3K pathway such as PIK3CA, and PIK3R1 were observed in both human AS and canine HSA, and the mutational landscape was associated with distinct molecular tumor subtypes; in particular, differing immunophenotypes. Recently, we have shown that human AS and canine HSA establish convergent transcriptional programs driven by angiogenic fusion genes and TP53 mutation. However, these vascular tumors are genomically complex, and molecular mechanisms that establish the tumor microenvironment are incompletely known. In this study, we analyzed RNA-seq transcriptomic data generated from human AS tissues (n=13) and canine HSA tissues (n=76) and HSA cell lines (n=11). The data showed that the tumors of both species enriched gene signatures associated with maintenance of hematopoietic stem cells. Then, we found that canine HSA cells supported expansion and differentiation of human CD34+ umbilical cord blood cells using long-term culture-initiating cell and colony-forming unit assays. We also developed xenograft models of canine HSA that facilitate myelopoiesis and macrophage infiltration in the tumor tissue. Our data showed that gene signatures of monocytes and naïve macrophages were detectable in canine HSA cells. In human ASs, macrophage-associated genes, in particular M2 macrophage signatures were significantly enriched, compared to normal tissues. Collectively, our data suggest that human AS and canine HSA have cell-autonomous capacity to govern hematopoietic progenitors and immune cells, potentially establishing the tumor immune niche. We engineered HSA cells to induce homozygous H1047R mutations in PIK3CA gene using CRISPR-Cas9 system. Our ongoing work is to determine if regulating PI3K pathway in the tumor cells contributes to the molecular programs that create the tumor niche of the vascular malignancy. Citation Format: Sophia Wenthe, Ashley J. Schulte, Mathew G. Angelos, Dan S. Kaufman, Jaime F. Modiano, Jong Hyuk Kim. Role of PI3K pathway in reprogramming the tumor niche of angiosarcoma [abstract]. In: Proceedings of the AACR Virtual Special Conference on the Evolving Tumor Microenvironment in Cancer Progression: Mechanisms and Emerging Therapeutic Opportunities; in association with the Tumor Microenvironment (TME) Working Group; 2021 Jan 11-12. Philadelphia (PA): AACR; Cancer Res 2021;81(5 Suppl):Abstract nr PO007.

Abstract LT017: ECM mechanical and metabolic architecture during early ductal invasions: integrating in silico modeling, histology-based machine learning and mechanobiology

Abstract Progression from a ductal carcinoma in situ (DCIS) to an invasive tumor is a major step initiating a devastating and often lethal metastatic cascade. One sentinel event that initiate this process is the development of ductal microinvasions, i.e., small cohorts of tumor cells that breach the basement membrane surrounding the duct and migrate through the extracellular matrix (ECM) leading to irreversible changes in tumor and stromal architecture. We used a combination of advanced image analysis techniques applied to patients’ histology data to extract features which identify specific properties of individual tumor cells inside the duct and on the invasive front. By integrating these histology-based data with a hybrid agent-based mathematical model, we investigated the biomechanical interactions between the cells and the ECM fiber architecture, and microenvironmental physical and metabolic features that define tumor niche prone to microinvasions. The identified physical properties of the matrix elucidate conditions that can facilitate or prevent the progression of such microinvasions. The presented method provides also a tool for quantifying morphological and immunohistochemical properties of individual cells within the mammary ducts and ductal microinvasion, as well as for testing biomechanical hypotheses of tumor cell-tumor matrix interactions. These findings can be compared to the patient histology samples and help define criteria for identification of changes in tumor architecture and future development of new diagnostic methods. Citation Format: Katarzyna A. Rejniak, Sharan Poonja, Shreya Mathur, Jessica Kingsley, Marilyn Bui. ECM mechanical and metabolic architecture during early ductal invasions: integrating in silico modeling, histology-based machine learning and mechanobiology [abstract]. In: Proceedings of the AACR Virtual Special Conference on the Evolving Tumor Microenvironment in Cancer Progression: Mechanisms and Emerging Therapeutic Opportunities; in association with the Tumor Microenvironment (TME) Working Group; 2021 Jan 11-12. Philadelphia (PA): AACR; Cancer Res 2021;81(5 Suppl):Abstract nr LT017.

The Microbiome and Cancer: Creating Friendly Neighborhoods and Removing the Foes Within.

The human body is colonized by the microbial cells that are estimated to be as abundant as human cells, yet their genome is roughly 100 times the human genome, providing significantly more genetic diversity. The past decade has observed an explosion of interest in examining the existence of microbiota in the human body and understanding its role in various diseases including inflammatory bowel disease, neurologic diseases, cardiovascular disorders, and cancer. Many studies have demonstrated differential community composition between normal tissue and cancerous tissue, paving the way for investigations focused on deciphering the cause-and-effect relationships between specific microbes and initiation and progression of various cancers. Also, evolving are the strategies to alter tumor-associated dysbiosis and move it toward eubiosis with holistic approaches to change the entire neighborhood or to neutralize pathogenic strains. In this review, we discuss important pathogenic bacteria and the underlying mechanisms by which they affect cancer progression. We summarize key microbiota alterations observed in multiple tumor niches, their association with clinical stages, and their potential use in cancer diagnosis and management. Finally, we discuss microbiota-based therapeutic approaches.

Noncoding RNAs in the Interplay between Tumor Cells and Cancer-Associated Fibroblasts: Signals to Catch and Targets to Hit

Simple SummaryCancer aggressiveness is the result of a proficient bidirectional interaction between tumor and stromal cells within the tumor microenvironment, among which a major role is played by the so-called cancer-associated fibroblasts. Upon such interplay, both cancer cells and fibroblasts are reprogrammed to sustain malignancy, with changes in the repertoire of noncoding RNAs, mainly microRNAs and long noncoding RNAs. Such molecules are also exchanged between the two cell types through extracellular vesicles. In this review, we summarize the current knowledge of microRNAs and long noncoding RNAs that act intracellularly or extracellularly to sustain tumor-stroma interplay. We also provide our view regarding the possible clinical utility of such noncoding RNAs as therapeutic target/tools or biomarkers to predict patient outcome or response to specific treatments.Cancer development and progression are not solely cell-autonomous and genetically driven processes. Dynamic interaction of cancer cells with the surrounding microenvironment, intended as the chemical/physical conditions as well as the mixture of non-neoplastic cells of the tumor niche, drive epigenetic changes that are pivotal for the acquisition of malignant traits. Cancer-associated fibroblasts (CAF), namely fibroblasts that, corrupted by cancer cells, acquire a myofibroblast-like reactive phenotype, are able to sustain tumor features by the secretion of soluble paracrine signals and the delivery extracellular vesicles. In such diabolic liaison, a major role has been ascribed to noncoding RNAs. Defined as RNAs that are functional though not being translated into proteins, noncoding RNAs predominantly act as regulators of gene expression at both the transcriptional and post-transcriptional levels. In this review, we summarize the current knowledge of microRNAs and long noncoding RNAs that act intracellularly in either CAFs or cancer cells to sustain tumor-stroma interplay. We also report on the major role of extracellular noncoding RNAs that are bidirectionally transferred between either cell type. Upon presenting a comprehensive view of the existing literature, we provide our critical opinion regarding the possible clinical utility of tumor-stroma related noncoding RNAs as therapeutic target/tools or prognostic/predictive biomarkers.