Evolution of Metastases in Space and Time under Immune Selection.

We examined how the immune microenvironment molds tumor evolution at different metastatic organs in a longitudinal dataset of colorectal cancer. Through multiplexed analyses, we showed that clonal evolution patterns during metastatic progression depend on the immune contexture at the metastatic site. Genetic evidence of neoantigen depletion was observed in the sites with high Immunoscore and spatial proximity between Ki67+ tumor cells and CD3+ cells. The immunoedited tumor clones were eliminated and did not recur, while progressing clones were immune privileged, despite the presence of tumor-infiltrating lymphocytes. Characterization of immune-privileged metastases revealed tumor-intrinsic and tumor-extrinsic mechanisms of escape. The lowest recurrence risk was associated with high Immunoscore, occurrence of immunoediting, and low tumor burden. We propose a parallel selection model of metastatic progression, where branched evolution could be traced back to immune-escaping clones. The findings could inform the understanding of cancer dissemination and the development of immunotherapeutics.

Immune evasion before tumour invasion in early lung squamous carcinogenesis.

Early detection and treatment are critical for improving the outcome of patients with cancer1. Understanding the largely uncharted biology of carcinogenesis requires deciphering molecular processes in premalignant lesions, and revealing the determinants of the intralesional immune reaction during cancer development. The adaptive immune response within tumours has previously been shown to be strongest at the earliest stage of carcinoma2,3. Here we show that immune activation and immune escape occur before tumour invasion, and reveal the relevant immune biomarkers of the pre-invasive stages of carcinogenesis in the lung. We used gene-expression profiling and multispectral imaging to analyse a dataset of 9 morphological stages of the development of lung squamous cell carcinoma, which includes 122 well-annotated biopsies from 77 patients. We identified evolutionary trajectories of cancer and immune pathways that comprise (1) a linear increase in proliferation and DNA repair from normal to cancerous tissue; (2) a transitory increase of metabolism and early immune sensing, through the activation of resident immune cells, in low-grade pre-invasive lesions; (3) the activation of immune responses and immune escape through immune checkpoints and suppressive interleukins from high-grade pre-invasive lesions; and, ultimately, (4) the activation of the epithelial-mesenchymal transition in the invasive stage of cancer. We propose that carcinogenesis in the lung involves a dynamic co-evolution of pre-invasive bronchial cells and the immune response. These findings highlight the need to develop immune biomarkers for early detection as well as immunotherapy-based chemopreventive approaches for individuals who are at high risk of developing lung cancer.

Prognostic value of intra-tumoral CD8+ /FoxP3+ lymphocyte ratio in patients with resected colorectal cancer liver metastasis.

BACKGROUND AND OBJECTIVES: Patients with isolated colorectal-cancer-liver-metastases (CRCLM) frequently undergo metastatectomy. Tumor-infiltrating-lymphocytes (TILs) have prognostic potential in the setting of primary colorectal cancer, however, their role in CRCLM is less studied. We aimed to study the spatial distribution and prognostic role of tumor-infiltrating CD8+ cytotoxic T-cells and FoxP3+ regulatory T-cells at the metastatic site of CRCLM patients. METHODS: TILs were isolated from fresh metastatic tissues of 47 patients with CRCLM. Archived paraffin-embedded tissue, from the same patients, was retrieved. CD8+ and FoxP3+ cells, both in the intra-tumoral and the peri-tumoral compartments, were measured by immunohistochemistry on full tissue sections. Proportions of cytotoxic T-cells (CD8+ ) and regulatory T-cells (CD4+ CD25+ FoxP3+ ), within CD45+ TILs, were measured by flow-cytometry. RESULTS: By immunohistochemistry, individual densities of intra-tumoral or peri-tumoral CD8+ and FoxP3+ cells were not prognostic of survival. However, the intra-tumoral, but not the peri-tumoral, CD8+ /FoxP3+ ratio was an independent predictor of survival (HR 0.43, 95%CI 0.19-0.95, P = 0.032). By flow cytometry, the intra-tumoral CD8+ /regulatory T-cell ratio was also an independent predictor of survival (HR 0.45, 95%CI 0.20-0.99, P = 0.044). CONCLUSIONS: The ratio of cytotoxic (CD8+ ) to regulatory (FoxP3+ ) T-cells, in the intra-tumoral compartment, but not in the peri-tumoral compartment, can predict survival after resection of CRCLM.

Semaphorin 7A Promotes Chemokine-Driven Dendritic Cell Migration.

Dendritic cell (DC) migration is essential for efficient host defense against pathogens and cancer, as well as for the efficacy of DC-based immunotherapies. However, the molecules that induce the migratory phenotype of DCs are poorly defined. Based on a large-scale proteome analysis of maturing DCs, we identified the GPI-anchored protein semaphorin 7A (Sema7A) as being highly expressed on activated primary myeloid and plasmacytoid DCs in human and mouse. We demonstrate that Sema7A deficiency results in impaired chemokine CCL21-driven DC migration in vivo. Impaired formation of actin-based protrusions, resulting in slower three-dimensional migration, was identified as the mechanism underlying the DC migration defect. Furthermore, we show, by atomic force microscopy, that Sema7A decreases adhesion strength to extracellular matrix while increasing the connectivity of adhesion receptors to the actin cytoskeleton. This study demonstrates that Sema7A controls the assembly of actin-based protrusions that drive DC migration in response to CCL21.

Multispectral imaging for highly accurate analysis of tumour-infiltrating lymphocytes in primary melanoma.

AIMS: The quality and quantity of the infiltration of immune cells into tumour tissues have substantial impacts on patients' clinical outcomes, and are associated with response to immunotherapy. Therefore, the precise analysis of tumour-infiltrating lymphocytes (TILs) is becoming an important additional pathological biomarker. Analysis of TILs is usually performed semiquantitatively by pathologists on haematoxylin and eosin-stained or immunostained tissue sections. However, automated quantification outperforms semiquantitative approaches, and is becoming the standard. Owing to the presence of melanin pigment, this approach is seriously hampered in melanoma, because the spectrum of melanin lies close to that of commonly used immunohistochemical stains. Aim of this study is to overcome the technical issues due to the presence of melanin for an automated and accurate quantification of TILs in melanoma. METHODS AND RESULTS: Here, we successfully applied a novel multispectral imaging (MSI) technique to enumerate T cells in human primary melanomas. This microscopy technique combines imaging with spectroscopy to obtain both quantitative expression data and the tissue distributions of different cellular markers. We demonstrate that MSI allows complete and accurate analysis of TILs, successfully avoiding the blurring of images by melanin pigments, in whole tissue slide primary melanoma lesions, which could otherwise not be accurately detected by conventional digital image methodologies. CONCLUSIONS: Our study highlights the potential of MSI for accurate assessment of immune cell infiltrates, including those in notoriously difficult tissues, such as pigmented melanomas. Quantification of tumour infiltration by different immune cell types is crucial in the search for new biomarkers to predict patient responses to immunotherapies. Our findings show that this innovative microscopy technique is an important extension of the armamentarium of pathologists.

Comparison between fibroblast wound healing and cell random migration assays in vitro.

Cell migration plays a key role in many biological processes, including cancer growth and invasion, embryogenesis, angiogenesis, inflammatory response, and tissue repair. In this work, we compare two well-established experimental approaches for the investigation of cell motility in vitro: the cell random migration (CRM) and the wound healing (WH) assay. In the former, extensive tracking of individual live cells trajectories by time-lapse microscopy and elaborate data processing are used to calculate two intrinsic motility parameters of the cell population under investigation, i.e. the diffusion coefficient and the persistence time. In the WH assay, a scratch is made in a confluent cell monolayer and the closure time of the exposed area is taken as an easy-to-measure, empirical estimate of cell migration. To compare WH and CRM we applied the two assays to investigate the motility of skin fibroblasts isolated from wild type and transgenic mice (TgPED) overexpressing the protein PED/PEA-15, which is highly expressed in patients with type 2 diabetes. Our main result is that the cell motility parameters derived from CRM can be also estimated from a time-resolved analysis of the WH assay, thus showing that the latter is also amenable to a quantitative analysis for the characterization of cell migration. To our knowledge this is the first quantitative comparison of these two widely used techniques.

Multispectral imaging reveals the tissue distribution of tetraspanins in human lymphoid organs.

Multispectral imaging is a novel microscopy technique that combines imaging with spectroscopy to obtain both quantitative expression data and tissue distribution of different cellular markers. Tetraspanins CD37 and CD53 are four-transmembrane proteins involved in cellular and humoral immune responses. However, comprehensive immunohistochemical analyses of CD37 and CD53 in human lymphoid organs have not been performed so far. We investigated CD37 and CD53 protein expression on primary human immune cell subsets in blood and in primary and secondary lymphoid organs. Both tetraspanins were prominently expressed on antigen-presenting cells, with highest expression of CD37 on B lymphocytes. Analysis of subcellular distribution showed presence of both tetraspanins on the plasma membrane and on endosomes. In addition, CD53 was also present on lysosomes. Quantitative analysis of expression and localization of CD37 and CD53 on lymphocytes within lymphoid tissues by multispectral imaging revealed high expression of both tetraspanins on CD20(+) cells in B cell follicles in human spleen and appendix. CD3(+) T cells within splenic T cell zones expressed lower levels of CD37 and CD53 compared to T cells in the red pulp of human spleen. B cells in human bone marrow highly expressed CD37, whereas the expression of CD53 was low. In conclusion, we demonstrate differential expression of CD37 and CD53 on primary human immune cells, their subcellular localization and their quantitative distribution in human lymphoid organs. This study provides a solid basis for better insight into the function of tetraspanins in the human immune response.

Multi-Institutional Evaluation of Pathologists' Assessment Compared to Immunoscore.

BACKGROUND: The Immunoscore (IS) is a quantitative digital pathology assay that evaluates the immune response in cancer patients. This study reports on the reproducibility of pathologists' visual assessment of CD3+- and CD8+-stained colon tumors, compared to IS quantification. METHODS: An international group of expert pathologists evaluated 540 images from 270 randomly selected colon cancer (CC) cases. Concordance between pathologists' T-score, corresponding hematoxylin-eosin (H&E) slides, and the digital IS was evaluated for two- and three-category IS. RESULTS: Non-concordant T-scores were reported in more than 92% of cases. Disagreement between semi-quantitative visual assessment of T-score and the reference IS was observed in 91% and 96% of cases before and after training, respectively. Statistical analyses showed that the concordance index between pathologists and the digital IS was weak in two- and three-category IS, respectively. After training, 42% of cases had a change in T-score, but no improvement was observed with a Kappa of 0.465 and 0.374. For the 20% of patients around the cut points, no concordance was observed between pathologists and digital pathology analysis in both two- and three-category IS, before or after training (all Kappa < 0.12). CONCLUSIONS: The standardized IS assay outperformed expert pathologists' T-score evaluation in the clinical setting. This study demonstrates that digital pathology, in particular digital IS, represents a novel generation of immune pathology tools for reproducible and quantitative assessment of tumor-infiltrated immune cell subtypes.

PED/PEA-15 controls fibroblast motility and wound closure by ERK1/2-dependent mechanisms.

Cell migration is dependent on the control of signaling events that play significant roles in creating contractile force and in contributing to wound closure. We evaluated wound closure in fibroblasts from mice overexpressing (TgPED) or lacking ped/pea-15 (KO), a gene overexpressed in patients with type 2 diabetes. Cultured skin fibroblasts isolated from TgPED mice showed a significant reduction in the ability to recolonize wounded area during scratch assay, compared to control fibroblasts. This difference was observed both in the absence and in the presence of mytomicin C, an inhibitor of mitosis. In time-lapse experiments, TgPED fibroblasts displayed about twofold lower velocity and diffusion coefficient, as compared to controls. These changes were accompanied by reduced spreading and decreased formation of stress fibers and focal adhesion plaques. At the molecular level, TgPED fibroblasts displayed decreased RhoA activation and increased abundance of phosphorylated extracellular signal-regulated kinase 1/2 (ERK1/2). Inhibition of ERK1/2 activity by PD98059 restored RhoA activation, cytoskeleton organization and cell motility, and almost completely rescued wound closure of TgPED fibroblasts. Interestingly, skin fibroblasts isolated from KO mice displayed an increased wound closure ability. In vivo, healing of dorsal wounds was delayed in TgPED and accelerated in KO mice. Thus, PED/PEA-15 may affect fibroblast motility by a mechanism, at least in part, mediated by ERK1/2.

Intratumoral administration of CD1c (BDCA-1)+ and CD141 (BDCA-3)+ myeloid dendritic cells in combination with talimogene laherparepvec in immune checkpoint blockade refractory advanced melanoma patients: a phase I clinical trial.

BACKGROUND: Intratumoral (IT) myeloid dendritic cells (myDCs) play a pivotal role in initiating antitumor immune responses and relicensing of anti-tumor cytotoxic T lymphocytes within the tumor microenvironment. Talimogene laherparepvec (T-VEC) induces immunogenic cell death, thereby providing maturation signals and enhancing the release of tumor antigens that can be captured and processed by CD1c (BDCA-1)+ / CD141 (BDCA-3)+ myDCs, in order to reinvigorate the cancer-immunity cycle. METHODS: In this phase I trial, patients with advanced melanoma who failed standard therapy were eligible for IT injections of ≥1 non-visceral metastases with T-VEC on day 1 followed by IT injection of CD1c (BDCA-1)+ myDCs +/- CD141 (BDCA-3)+ myDCs on day 2. T-VEC injections were repeated on day 21 and every 14 days thereafter. The number of IT administered CD1c (BDCA-1)+ myDCs was escalated from 0.5×106, to 1×106, to a maximum of 10×106 cells in three sequential cohorts. In cohort 4, all isolated CD1c (BDCA-1)+ / CD141 (BDCA-3)+ myDCs were used for IT injection. Primary objectives were safety and feasibility. Repetitive biopsies of treated lesions were performed. RESULTS: In total, 13 patients were enrolled (cohort 1 n=2; cohort 2 n=2; cohort 3 n=3; cohort 4 n=6). Patients received a median of 6 (range 3-8) T-VEC injections. The treatment was safe with most frequent adverse events being fatigue (n=11 (85%)), fever (n=8 (62%)), and chills/influenza-like symptoms (n=6 (46%)). Nine (69%) and four patients (31%), respectively, experienced pain or redness at the injection-site. Clinical responses were documented in injected and non-injected lesions. Two patients (cohort 3) who previously progressed on anti-PD-1 therapy (and one patient also on anti-CTLA-4 therapy) developed a durable, pathologically confirmed complete response that is ongoing at 33 and 35 months following initiation of study treatment. One additional patient treated (cohort 4) had an unconfirmed partial response as best response; two additional patients had a mixed response (with durable complete responses of some injected and non-injected lesions). On-treatment biopsies revealed a strong infiltration by inflammatory cells in regressing lesions. CONCLUSIONS: IT coinjection of autologous CD1c (BDCA-1)+ +/- CD141 (BDCA-3)+ myDCs with T-VEC is feasible, tolerable and resulted in encouraging early signs of antitumor activity in immune checkpoint inhibitor-refractory melanoma patients. TRIAL REGISTRATION NUMBER: NCT03747744.

Two-photon laser-generated microtracks in 3D collagen lattices: principles of MMP-dependent and -independent collective cancer cell invasion.

Cancer invasion into an extracellular matrix (ECM) results from a biophysical reciprocal interplay between the expanding cancer lesion and tissue barriers imposed by the adjacent microenvironment. In vivo, connective tissue provides both densely packed ECM barriers adjacent to channel/track-like spaces and loosely organized zones, both of which may impact cancer invasion mode and efficiency; however little is known about how three-dimensional (3D) spaces and aligned tracks present in interstitial tissue guide cell invasion. We here describe a two-photon laser ablation procedure to generate 3D microtracks in dense 3D collagen matrices that support and guide collective cancer cell invasion. Whereas collective invasion of mammary tumor (MMT) breast cancer cells into randomly organized collagen networks required matrix metalloproteinase (MMP) activity for cell-derived collagen breakdown, re-alignment and track generation, preformed tracks supported MMP-independent collective invasion down to a track caliber of 3 µm. Besides contact guidance along the track of least resistance and initial cell deformation (squeezing), MMP-independent collective cell strands led to secondary track expansion by a pushing mechanism. Thus, two-photon laser ablation is useful to generate barrier-free microtracks in a 3D ECM which guide collective invasion independently of pericellular proteolysis.

SUMOylation of tissue transglutaminase as link between oxidative stress and inflammation.

Cystic fibrosis (CF) is a monogenic disease caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. CF is characterized by chronic bacterial lung infections and inflammation, and we have previously reported that tissue transglutaminase (TG2), a multifunctional enzyme critical to several diseases, is constitutively up-regulated in CF airways and drives chronic inflammation. Here, we demonstrate that the generation of an oxidative stress induced by CFTR-defective function leads to protein inhibitor of activated STAT (PIAS)y-mediated TG2 SUMOylation and inhibits TG2 ubiquitination and proteasome degradation, leading to sustained TG2 activation. This prevents peroxisome proliferator-activated receptor (PPAR)gamma and IkBalpha SUMOylation, leading to NF-kappaB activation and to an uncontrolled inflammatory response. Cellular homeostasis can be restored by small ubiquitin-like modifier (SUMO)-1 or PIASy gene silencing, which induce TG2 ubiquitination and proteasome degradation, restore PPARgamma SUMOylation, and prevent IkBalpha cross-linking and degradation, thus switching off inflammation. Manganese superoxide dismutase overexpression as well as the treatment with the synthetic superoxide dismutase mimetic EUK-134 control PIASy-TG2 interaction and TG2 SUMOylation. TG2 inhibition switches off inflammation in vitro as well as in vivo in a homozygous F508del-CFTR mouse model. Thus, TG2 may function as a link between oxidative stress and inflammation by driving the decision as to whether a protein should undergo SUMO-mediated regulation or degradation. Targeting TG2-SUMO interactions might represent a new option to control disease evolution in CF patients as well as in other chronic inflammatory diseases, neurodegenerative pathologies, and cancer.

Lysosomal accumulation of gliadin p31-43 peptide induces oxidative stress and tissue transglutaminase-mediated PPARgamma downregulation in intestinal epithelial cells and coeliac mucosa.

BACKGROUND: An unresolved question in coeliac disease is to understand how some toxic gliadin peptides, in particular p31-43, can initiate an innate response and lead to tissue transglutaminase (TG2) upregulation in coeliac intestine and gliadin sensitive epithelial cell lines. Aim We addressed whether the epithelial uptake of p31-43 induces an intracellular pro-oxidative envoronment favouring TG2 activation and leading to the innate immune response. METHODS: The time course of intracellular delivery to lysosomes of p31-43, palpha-2 or palpha-9 gliadin peptides was analysed in T84 and Caco-2 epithelial cells. The effects of peptide challenge on oxidative stress, TG2 and peroxisome proliferator-activated receptor (PPAR)gamma ubiquitination and p42/44-mitogen activated protein (MAP) kinase or tyrosine phosphorylation were investigated in cell lines and cultured coeliac disease biopsies with/without anti-oxidant treatment or TG2 gene silencing by immunoprecipitation, western blot, confocal microscopy and Fluorenscence Transfer Resonance Energy (FRET) analysis. RESULTS: After 24 h of challenge p31-43, but not palpha-2 or palpha-9, is still retained within LAMP1-positive perinuclear vesicles and leads to increased levels of reactive oxygen species (ROS) that inhibit TG2 ubiquitination and lead to increases of TG2 protein levels and activation. TG2 induces cross-linking, ubiquitination and proteasome degradation of PPARgamma. Treatment with the antioxidant EUK-134 as well as TG2 gene silencing restored PPARgamma levels and reversed all monitored signs of innate activation, as indicated by the dramatic reduction of tyrosine and p42/p44 phosphorylation. CONCLUSION: p31-43 accumulation in lysosomes leads to epithelial activation via the ROS-TG2 axis. TG2 works as a rheostat of ubiquitination and proteasome degradation and drives inflammation via PPARgamma downregulation.

Multiplexed immunohistochemistry for immune cell phenotyping, quantification and spatial distribution in situ.

It is increasingly recognized that a deep characterization of the immune microenvironment is required for the identification of prognostic and predictive immune biomarkers. Recent advances in the field of tissue imaging resulted in the development of fluorescence multiplex IHC technologies enabling quantitative assessment of immune phenotypes and functional orientation of immune cells in a way similar to flow cytometry, while simultaneously providing tissue context and spatial distribution. Multiplex immunofluorescent technology to FFPE tumor tissue is applied to characterize immune infiltration and PD-L1 expression. A panel consists of five protein markers: CD8, CD68, PD-L1, CK, and SOX10. The assay workflow is fast, optimized and compatible with existing instrumentation. The resulting images can be analyzed with routinely used software for digital pathology enabling the quantification of dynamic range of expression, co-localization and co-expression of markers in the whole tissue. In this chapter, we provide the protocol for the use of the UltiMapper™ I/O PD-L1 multiplex assay, from the bench to the image analysis, as well as an overview of the current multiplex image analysis solutions. Such deep profiling could guide the development of strategies to better select immune checkpoint molecules and a better stratification of patients who will potentially benefit from immunotherapies.

Collective invasion induced by an autocrine purinergic loop through connexin-43 hemichannels.

Progression of epithelial cancers predominantly proceeds by collective invasion of cell groups with coordinated cell-cell junctions and multicellular cytoskeletal activity. Collectively invading breast cancer cells express the gap junction protein connexin-43 (Cx43), yet whether Cx43 regulates collective invasion remains unclear. We here show that Cx43 mediates gap-junctional coupling between collectively invading breast cancer cells and, via hemichannels, adenosine nucleotide/nucleoside release into the extracellular space. Using molecular interference and rescue strategies, we identify that Cx43 hemichannel function, but not intercellular communication, induces leader cell activity and collective migration through the engagement of the adenosine receptor 1 (ADORA1) and AKT signaling. Accordingly, pharmacological inhibition of ADORA1 or AKT signaling caused leader cell collapse and halted collective invasion. ADORA1 inhibition further reduced local invasion of orthotopic mammary tumors in vivo, and joint up-regulation of Cx43 and ADORA1 in breast cancer patients correlated with decreased relapse-free survival. This identifies autocrine purinergic signaling, through Cx43 hemichannels, as a critical pathway in leader cell function and collective invasion.

Comprehensive Intrametastatic Immune Quantification and Major Impact of Immunoscore on Survival.

Background: This study assesses how the metastatic immune landscape is impacting the response to treatment and the outcome of colorectal cancer (CRC) patients. Methods: Complete curative resection of metastases (n = 441) was performed for two patient cohorts (n = 153). Immune densities were quantified in the center and invasive margin of all metastases. Immunoscore and T and B cell (TB) score were analyzed in relation to radiological and pathological responses and patient's disease-free (DFS) and overall survival (OS) using multivariable Cox proportional hazards models. All statistical tests were two-sided. Results: The spatial distribution of immune cells within metastases was nonuniform. Patients, as well as metastases of the same patient, had variable immune infiltrates and response to therapy. A beneficial response was statistically significantly associated with increased immune densities. Among all metastases, Immunoscore (I) and TB score evaluated in the least immune-infiltrated metastases were the strongest predictors for DFS and OS (five-year follow-up, Immunoscore: I 3-4: DFS rate = 27.9%, 95% CI = 15.2 to 51.3; vs I 0-1-2: DFS rate = 12.3%, 95% CI = 4.9 to 30.6; HR = 0.45, 95% CI = 0.28 to 0.70, P = .02; I 3-4: OS rate = 64.6%, 95% CI = 46.6 to 89.6; vs I 0-1-2: OS rate = 32.5%, 95% CI = 17.2 to 61.4; HR = 0.32, 95% CI = 0.15 to 0.66, P = .001, C-index = 65.9%; five-year follow-up, TB score: TB 3-4: DFS rate = 25.7%, 95% CI = 14.2 to 46.6; vs TB 0-1-2: DFS rate = 5.0%, 95% CI = 0.8 to 32.4; HR = 0.36, 95% CI = 0.22 to 0.57, P < .001; TB 3-4: OS rate = 63.7%, 95% CI = 46.4 to 87.5; vs TB 0-1-2: OS rate: 21.4%, 95% CI = 9.2 to 49.8; HR = 0.25, 95% CI = 0.12 to 0.51, P < .001, C-index = 67.8%). High TB score and Immunoscore patients had a median survival of 70.5 months, while low patients survived only 25.1 to 38.3 months. Nonresponding patients with high-immune infiltrates had prolonged DFS (HR = 0.28, 95% CI = 0.15 to 0.52, P = .001) and OS (HR = 0.25, 95% CI = 0.1 to 0.62, P = .001). The immune parameters remained the only statistically significant prognostic factor associated with DFS and OS in multivariable analysis (P < .001), while response to treatment was not. Conclusions: Response to treatment and prolonged survival of metastatic CRC patients were statistically significantly associated with high-immune densities quantified into the least immune-infiltrated metastasis.

The Link between the Multiverse of Immune Microenvironments in Metastases and the Survival of Colorectal Cancer Patients.

Treatment of metastatic colorectal cancer is based upon the assumption that metastases are homogeneous within a patient. We quantified immune cell types of 603 whole-slide metastases and primary colorectal tumors from 222 patients. Primary lesions, and synchronous and metachronous metastases, had a heterogeneous immune infiltrate and mutational diversity. Small metastases had frequently a low Immunoscore and T and B cell score, while a high Immunoscore was associated with a lower number of metastases. Anti-epidermal growth factor receptor treatment modified immune gene expression and significantly increased T cell densities in the metastasis core. The predictive accuracy of the Immunoscore from a single biopsy was superior to the one of programmed cell death ligand 1 (PD-L1). The immune phenotype of the least-infiltrated metastasis had a stronger association with patient outcome than other metastases.

Direct inhibition of STAT signaling by platinum drugs contributes to their anti-cancer activity.

Platinum-based chemotherapeutics are amongst the most powerful anti-cancer drugs. Although their exact mechanism of action is not well understood, it is thought to be mediated through covalent DNA binding. We investigated the effect of platinum-based chemotherapeutics on signaling through signal transducer and activator of transcription (STAT) proteins, which are involved in many oncogenic signaling pathways. We performed in vitro experiments in various cancer cell lines, investigating the effects of platinum chemotherapeutics on STAT phosphorylation and nuclear translocation, the expression of STAT-modulating proteins and downstream signaling pathways. Direct binding of platinum to STAT proteins was assessed using an AlphaScreen assay. Nuclear STAT3 expression was determined by immunohistochemistry and correlated with disease-free survival in retrospective cohorts of head and neck squamous cell carcinoma (HNSCC) patients treated with cisplatin-based chemoradiotherapy (n= 65) or with radiotherapy alone (n = 32). At clinically relevant concentrations, platinum compounds inhibited STAT phosphorylation, resulting in loss of constitutively activated STAT proteins in multiple distinct cancer cell lines. Platinum drugs specifically inhibited phospho-tyrosine binding to SH2 domains, thereby blocking STAT activation, and subsequently downregulating pro-survival- and anti-apoptotic- target genes. Importantly, we found that active STAT3 in tumors directly correlated with response to cisplatin-based chemoradiotherapy in HNSCC patients (p = 0.006). These findings provide insight into a novel, non-DNA-targeted mechanism of action of platinum drugs, and could be leveraged into the use of STAT expression as predictive biomarker for cisplatin chemotherapy and to potentiate other therapeutic strategies such as immunotherapy.

Co-delivery of PLGA encapsulated invariant NKT cell agonist with antigenic protein induce strong T cell-mediated antitumor immune responses.

Antitumor immunity can be enhanced by the coordinated release and delivery of antigens and immune-stimulating agents to antigen-presenting cells via biodegradable vaccine carriers. So far, encapsulation of TLR ligands and tumor-associated antigens augmented cytotoxic T cell (CTLs) responses. Here, we compared the efficacy of the invariant NKT (iNKT) cell agonist α-galactosylceramide (α-GalCer) and TLR ligands (R848 and poly I:C) as an adjuvant for the full length ovalbumin (OVA) in PLGA nanoparticles. We observed that OVA+α-GalCer nanoparticles (NP) are superior over OVA+TLR-L NP in generating and stimulating antigen-specific cytotoxic T lymphocytes without the need for CD4+ T cell help. Not only a 4-fold higher induction of antigen-specific T cells was observed, but also a more profound IFN-γ secretion was obtained by the addition α-GalCer. Surprisingly, we observed that mixtures of OVA containing NP with α-GalCer were ineffective, demonstrating that co-encapsulation of both α-GalCer and antigen within the same nanoparticle is essential for the observed T cell responses. Moreover, a single immunization with OVA+α-GalCer NP provided substantial protection from tumor formation and even delayed the growth of already established tumors, which coincided with a prominent and enhanced antigen-specific CD8+ T cell infiltration. The provided evidence on the advantage of antigen and α-GalCer coencapsulation should be considered in the design of future nanoparticle vaccines for therapeutic purposes.

The tumor microenvironment and Immunoscore are critical determinants of dissemination to distant metastasis.

Although distant metastases account for most of the deaths in cancer patients, fundamental questions regarding mechanisms that promote or inhibit metastasis remain unanswered. We show the impact of mutations, genomic instability, lymphatic and blood vascularization, and the immune contexture of the tumor microenvironment on synchronous metastases in large cohorts of colorectal cancer patients. We observed large genetic heterogeneity among primary tumors, but no major differences in chromosomal instability or key cancer-associated mutations. Similar patterns of cancer-related gene expression levels were observed between patients. No cancer-associated genes or pathways were associated with M stage. Instead, mutations of FBXW7 were associated with the absence of metastasis and correlated with increased expression of T cell proliferation and antigen presentation functions. Analyzing the tumor microenvironment, we observed two hallmarks of the metastatic process: decreased presence of lymphatic vessels and reduced immune cytotoxicity. These events could be the initiating factors driving both synchronous and metachronous metastases. Our data demonstrate the protective impact of the Immunoscore, a cytotoxic immune signature, and increased marginal lymphatic vessels, against the generation of distant metastases, regardless of genomic instability.