Host Antitumor Response Research Articles

Tumor-Associated Monocytes Reprogram CD8+ T Cells into Central Memory-Like Cells with Potent Antitumor Effects.

CD8+ T cells are critical for host antitumor responses, whereas persistent antigenic stimulation and excessive inflammatory signals lead to T cell dysfunction or exhaustion. Increasing early memory T cells can improve T cell persistence and empower T cell-mediated tumor eradication, especially for adoptive cancer immunotherapy. Here, it is reported that tumor-associated monocytes (TAMos) are highly correlated with the accumulation of CD8+ memory T cells in human cancers. Further analysis identifies that TAMos selectively reprogram CD8+ T cells into T central memory-like (TCM-like) cells with enhanced recall responses. L-NMMA, a pan nitric oxide synthase inhibitor, can mitigate TAMo-mediated inhibition of T cell proliferation without affecting TCM-like cell generation. Moreover, the modified T cells by TAMo exposure and L-NMMA treatment exhibit long-term persistence and elicit superior antitumor effects in vivo. Mechanistically, the transmembrane protein CD300LG is involved in TAMo-mediated TCM-like cell polarization in a cell-cell contact-dependent manner. Thus, the terminally differentiated TAMo subset (CD300LGhighACElow) mainly contributes to TCM-like cell development. Taken together, these findings establish the significance of TAMos in boosting T-cell antitumor immunity.

The Role of Nonmetastatic Lymph Nodes in the Survival of Colorectal Cancer: A Systematic Review.

In this review, we aim to provide an overview of literature on lymph node (LN) histomorphological features and their relationship with the prognosis in colorectal cancer (CRC). Lymph nodes play a crucial role in the treatment and prognosis of CRC. The presence of LN metastases considerably worsens the prognosis in CRC patients. Literature has shown that the total number of LNs and the number negative LNs (LNnegs) has prognostic value in CRC patients. In esophageal carcinoma, LN size seems to be surrogate of the host antitumor response and a potentially clinically useful new prognostic biomarker for (y)pN0 esophageal carcinoma. A comprehensive search was performed in Pubmed, Embase, Medline, CINAHL, and the Cochrane library in March 2021. The PRISMA guidelines were followed. Only studies focusing on histomorphological features and LN size and their relation to overall survival were selected. A total of 9 unique articles met all inclusion criteria and were therefore included in this systematic review. Six of these studies investigated HMF (eg, paracortical hyperplasia, germinal center predominance, and sinus histiocytosis) and 4 studies LNneg size and their relationship with overall survival. The presence of paracortical hyperplasia and an increased number of large LNnegs is related to a more favorable prognosis in CRC. The results of this systematic review seem to support the hypothesis that there is a relationship between the host antitumor response reflected in different histomorphological reaction patterns visible in LNnegs and LNneg size related to survival in CRC patients.

On the Individualized Cancer Management

Individualized cancer management is the opposite of the standardized care adapted for current clinical practice by the mainstream medicine. It is not a fancy concept but a logic and inevitable reality derived from the intrinsic characteristics of cancer and host antitumor response. The question is not whether it should be done but how it is done. Previous efforts have identified various cancer driver gene mutations in individual cancer patient, which have provided basis for treating different patients with different drugs that target various mutated kinases that drive tumor replication. This progress has made one step towards individualized cancer management with limited success in the past two decades in certain type of cancer. A much larger step awaits to be made towards true individualized management of cancer. This step is based on the individual differences in antitumor immunity in different cancer patients. Because antitumor immunity is the most impacting factor for cancer survival once the malignancy of a tumor is established, to fully recognize and utilize this force in the battle against cancer maximize patient survival to the theoretical limit. A true individualized cancer therapy is not only based on personal situation for each patient, but must also satisfy the criterion that the outcome of selected therapy is predictable for that patient, a feature that current standardized care does not have. Thus, treating each patient according to the status of his antitumor immunity should be the most critical skills a physician needs to master when facing each individual cancer patient. In the past nine years, we have been exploring individualized management of cancer through recognizing and manipulating antitumor immunity in each patient. Our combined experiences indicate a significant benefit to patient survival with reduced costs even when such effort was not perfect in the past. With time and more learning, we see this practice becoming more and more practical in a clinical setting. When this individualized approach becomes guideline for cancer management, we will see a significant leap of clinical improvement on both patient survival and cancer cure rate.

CD-NTase family member MB21D2 promotes cGAS-mediated antiviral and antitumor immunity.

cGAS/DncV-like nucleotidyltransferase (CD-NTase) family members are immune sensors that synthesize diverse nucleotide signals to initiate antiviral response in bacteria and animals. As a founding member of CD-NTase enzyme, cGAS has been identified as a key sensor for cytoplasmic DNA and type I interferons (IFNs) signaling in metazoan. However, the functions of other metazoan CD-NTases remain enigmatic. Here, we showed that Mab-21 domain-containing protein 2 (MB21D2), another member of the CD-NTase family, plays a positive role in modulating the cGAS-STING signaling in myeloid cells. Deficiency of MB21D2 in THP-1 cells or mice macrophages led to impaired production of type I interferon upon DNA stimulation. Consistently, Mb21d2-/- mice showed more susceptible to infection with DNA virus and faster growth of melanoma, compared to its counterparts. Mechanistically, MB21D2 specially bound with the N-terminal of cGAS, facilitated its liquid phase condensation and DNA-binding activity, leading to the enhanced production of cGAMP and subsequent IFN-β production. Thus, our findings unveiled that the CD-NTase family member MB21D2 contributes to host antiviral and antitumor responses by enhancing cGAS activation.

Immunoediting instructs tumor metabolic reprogramming to support immune evasion

Immunoediting sculpts immunogenicity and thwarts host anti-tumor responses in tumor cells during tumorigenesis; however, it remains unknown whether metabolic programming of tumor cells can be guided by immunosurveillance. Here, we report that Tcell-mediated immunosurveillance in early-stage tumorigenesis instructs c-Myc upregulation and metabolic reprogramming in tumor cells. This previously unexplored tumor-immune interaction is controlled by non-canonical interferon gamma (IFNγ)-STAT3 signaling and supports tumor immune evasion. Our findings uncover that immunoediting instructs deregulated bioenergetic programs in tumor cells to empower them to disarm the Tcell-mediated immunosurveillance by imposing metabolic tug-of-war between tumor and infiltrating Tcells and forming the suppressive tumor microenvironment.

T-Cell Mediated Immunity in Merkel Cell Carcinoma.

Merkel cell carcinoma (MCC) is a rare and frequently lethal skin cancer with neuroendocrine characteristics. MCC can originate from either the presence of MCC polyomavirus (MCPyV) DNA or chronic ultraviolet (UV) exposure that can cause DNA mutations. MCC is predominant in sun-exposed regions of the body and can metastasize to regional lymph nodes, liver, lungs, bone, and brain. Older, light-skinned individuals with a history of significant sun exposure are at the highest risk. Previous studies have shown that tumors containing a high number of tumor-infiltrating T-cells have favorable survival, even in the absence of MCPyV DNA, suggesting that MCPyV infection enhances T-cell infiltration. However, other factors may also play a role in the host antitumor response. Herein, we review the impact of tumor infiltrating lymphocytes (TILs), mainly the CD4+, CD8+, and regulatory T-cell (Tregs) responses on the course of MCC, including their role in initiating MCPyV-specific immune responses. Furthermore, potential research avenues related to T-cell biology in MCC, as well as relevant immunotherapies are discussed.

Stk10 Deficiency in Mice Promotes Tumor Growth by Dysregulating the Tumor Microenvironment

Serine-threonine kinase 10 (STK10) is a member of the STE20/p21-activated kinase (PAK) family and is predominantly expressed in immune organs. Our previous reports suggested that STK10 participates in the growth and metastasis of prostate cancer via in vitro and in vivo data. However, the correlation between STK10 and the tumor microenvironment (TME) remains unclear. In this study, we assessed the relationship between STK10 and the immune cells in the tumor microenvironment of prostate cancer through bioinformatic analysis, and investigated the role of Stk10 in tumor growth using an Stk10 knockout mouse model. The results showed that STK10 is significantly associated with the tumor-infiltrating immune cells including lymphocytes, neutrophils, macrophages and dendritic cells. The target deletion of host Stk10 results in increased tumor growth, due to decreased activated/effector cytotoxic T lymphocytes (CTLs) and increased vessel density in the TME. In conclusion, we demonstrate that host Stk10 is involved in the host anti-tumor response by modulating the activated tumor-infiltrated CTLs and angiogenesis.

ITK Inhibitor Induces Dose-Dependent Th1 Skewing in Normal T Cells and Is Active in Refractory T Cell Lymphomas

Introduction Interleukin 2 inducible T cell kinase (ITK) is a TEC family tyrosine kinase expressed in T cells with an important role both in T cell receptor (TCR) signaling and T helper cell differentiation. Resting lymphocyte kinase (RLK), a closely related kinase, is redundant to ITK and is involved in the differentiation of naïve T cells into Th1 T cells. ITK-/- mice exhibit defects in Th2 differentiation while retaining the ability to differentiate into Th1 cells that secrete IFNγ; whereas, double ITK/RLK knockout mice exhibit profound defects in T cell function. Th1 cells are needed for various cytotoxic T cell functions such as destruction of tumor cells. CPI-818 is a covalent inhibitor of ITK (KD 2.5nM) with > 100 fold selectivity over RLK and other TEC family kinases. CPI-818 is being evaluated in an ongoing phase 1 trial in patients (pts) with refractory T cell lymphomas (TCL). We now report that selective ITK blockade with CPI-818 induces Th1 skewing of normal T cells and demonstrates anti-tumor activity. Methods Normal human peripheral blood mononuclear cells (PBMC) were stimulated in vitro for 6 days with anti-CD3/CD28 in the presence of CPI-818. Th1 cells were measured by flow cytometry based on ratio of IFNγ:IL4 staining cells. Sezary cells were similarly stimulated in the presence of CPI-818. Peripheral blood and tumor samples were stained with antibodies to CD3, 4, 8, 183, 196, 197 and 45RA to enumerate Th1 and other T cell subsets using multicolor flow cytometry. Successive cohorts of TCL pts were treated in a phase 1 trial until disease progression with continuous oral dosing of CPI-818 100mg, 200mg, 400mg or 600mg given BID. Results T cell receptor stimulated PBMC from 12 healthy donors incubated in vitro with CPI-818 demonstrated Th1 skewing at concentrations of 0.1 to < 10uM (Figure 1). Maximal skewing was seen at 1uM; cell viability was unaffected but, proliferation was inhibited at 10uM. Similar studies using Th2 Sezary cells showed inhibition of proliferation with CPI-818 (0.5-2.5uM). Thirty-three pts with TCL with a median age of 62 yrs and median of 4 prior therapies were enrolled. Histologies included: PTCL-NOS (17), AITL (4), and CTCL (12). The most common (≥ 10%) AEs were nausea, chills, vomiting, fatigue, pyrexia, decreased appetite, pruritus, and rash. Treatment-related Grade 3+ AEs were: anemia (1), lymphocytosis (1), WBC decreased (1) and neutropenia (1). The swimmer plot (Figure 2) shows a dose-dependent relationship with an optimum dose of 200mg (N=10) producing 1 CR 25 mo; 1 PR 2+ mo; 1 nodal CR 16 mo (CTCL); 2 SD; 1 PD; 4 not yet evaluated; 6 pts remain on treatment. Pharmacokinetic and target occupancy studies for the 200mg dose showed mean plasma Cmax of 2.3uM (SD 1.9uM) and ITK target occupancy of >75%. Analysis of blood in 4 of 4 pts treated in this cohort showed increases in Th1 cells (CD3+/CD4+/CD8-/CD183+/CD196-) compared to baseline and increases in terminally differentiated T effector memory cells (TEMRA CD3+/CD4-/CD8+/CD197-/CD45RA+). Tumor biopsy from 1 patient taken during response demonstrated an increase in Th1 (0 to 40%) and TEMRA CD8+ T cells (2.83% to 18.6%). CPI-818 reduced blood eosinophils (Eos) in 3 of 3 pts in this cohort with elevated Eos count, consistent with inhibition of Th2 function. Conclusions This study demonstrates that selective inhibition of ITK, while sparing RLK, induces Th1 skewing. As expected, the effects on T cell differentiation and proliferation are dose dependent: lower doses induce Th1 skewing and higher concentrations in vitro and in vivo lead to inhibition of TCR signaling and proliferation. Tumor responses were observed in several patients receiving 200mg BID, which achieves drug plasma levels consistent with Th1 skewing observed in vitro. The increases in Th1 cells and TEMRA CD8+ cells suggest that anti-tumor activity is due to induction of a host anti-tumor response. This raises the possibility that immunomodulation with ITK blockade could be used for immunotherapy of other cancers. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Complex interaction and heterogeneity among cancer stem cells in head and neck squamous cell carcinoma revealed by single-cell sequencing.

Cancer stem cells (CSCs) have been characterized to be responsible for multidrug resistance, metastasis, recurrence, and immunosuppressive in head and neck squamous cell carcinoma (HNSCC). However, the diversity of CSCs remains to be investigated. In this study, we aimed to determine the heterogeneity of CSCs and its effect on the formation of tumor microenvironment (TME). We depicted the landscape of HNSCC transcriptome profile by single-cell RNA-sequencing analysis of 20 HNSCC tissues from public databases, to reveal the Cell components, trajectory changes, signaling network, malignancy status and functional enrichment of CSCs within tumors. Immune checkpoint molecules CD276, LILRB2, CD47 were significantly upregulated in CSCs, enabling host antitumor response to be weakened or damaged. Notably, naive CSCs were divided to 2 different types of cells with different functions, exhibiting functional diversity. In addition, CSCs underwent self-renewal and tumor metastasis activity through WNT and ncWNT signaling. Among them, Regulon regulators (IRF1_394g, IRF7_160g, NFKB1_12g, NFKB2_33g and STAT1_356g) were activated in subgroups 2 and 3, suggesting their pivotal roles in the inflammatory response process in tumors. Among all CSCs, naive CSCs appear to be the most malignant resulting in a worse prognosis. Our study reveals the major signal transduction and biological function of CSCs during HNSCC progression, highlighting the heterogeneity of CSCs and their underlying mechanisms in the formation of an immunosuppressive TME. Therefore, our study about heterogeneity of CSCs in HNSCC can bring new insights for the treatment of HNSCC.

DCLK1 Suppresses Tumor-Specific Cytotoxic T Lymphocyte Function Through Recruitment of MDSCs via the CXCL1-CXCR2 Axis

Gastrointestinal cancer stem cell marker doublecortin-like kinase (DCLK1) is strongly associated with poor outcomes in colorectal cancer (CRC). Although DCLK1's regulatory effect on the tumor immune microenvironment has been hypothesized, its mode of action has not been shown previously invivo, which hampers the potential intervention based on this molecule for clinical practice. To define the immunomodulatory mechanisms of DCLK1 invivo, we generated DCLK1-/- tumor cells by Clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9 (Cas9) and developed subcutaneous and intestinal orthotopic transplantation tumor models. Tumor tissues were harvested and subjected to immunofluorescence staining, flow cytometry analysis of tumor-infiltrating immune cell populations, tumor myeloid-derived suppressor cell (MDSC) sorting by isolation kit and then co-culture with spleen T cells, and RNA sequencing for transcriptomic analysis. We found that DCLK1-/- tumor cells lose their tumorigenicity under immune surveillance. Failed tumor establishment of DCLK1-/- was associated with an increase in infiltration of CD8+ T cells and effector CD4+ T cells, and reduced numbers of MDSCs in the tumor tissue. Furthermore, DCLK1 promoted the up-regulation of C-X-C motif ligand 1, which recruits MDSCs in CRC through chemokine C-X-C motif receptor 2. The ability of invivo tumor growth of DCLK1-/- tumor cells was rescued by C-X-C motif ligand 1 overexpression. Collectively, we validated that DCLK1 promotes tumor growth in CRC through recruitment of T-cell-suppressive MDSCs. DCLK1-mediated immune suppression in tumor models allows escaping from the host's antitumor response. Because DCLK1 is one of the most common markers in gastrointestinal tumors, these results identify a precise therapeutic target for related clinical interventions.

Analysis of gene expression levels and their impact on survival in 31 cancer-types patients identifies novel prognostic markers and suggests unexplored immunotherapy treatment options in a wide range of malignancies

BackgroundImmunotherapy has dramatically improved cancer treatment by inhibiting or activating specific cell receptors, thus unleashing the host anti-tumor response. However, the engagement of the three main immune checkpoints so far identified, CTLA4, PD-1 and PD-L1, is effective in a fraction of patients, therefore novel targets must be identified and tested.MethodsWe focused our attention on the following nine highly relevant immune checkpoint (ICR) receptors: CTLA4, PD1, PD-L1, LAG3, TIM3, OX40, GITR, 4-1BB and TIGIT. All of them are targets of existing drugs currently under clinical scrutiny in several malignancies. Their expression levels were evaluated in patient tissues of 31 different cancer types vs. proper controls, in a total of 15,038 individuals. This analysis was carried out by interrogating public databases available on GEPIA2 portal and UALCAN portal. By the Principal Component Analysis (PCA) their ability to effectively discriminate patients form controls was then investigated. Expression of the nine ICRs was also related to overall survival in 31 cancer types and expressed as Hazard Ratio, on the GEPIA2 portal and validated, for melanoma patients, in patients-datasets available on PROGgene V2 portal.ResultsSignificant differential expression was observed for each ICR molecule in many cancer types. A 7-molecules profile was found to specifically discriminate melanoma patients from controls, while two different 6-molecules profiles discriminate pancreatic cancer patients and Testicular Germ Cell Tumors from matched controls. Highly significant survival improvement was found to be related to the expression levels of all nine ICRs in a wide spectrum of malignancies. For melanoma analysis, the relation with survival observed in TCGA datasets was validated in independent GSE melanoma datasets.ConclusionAnalysis the nine ICR molecules demonstrates that their expression patterns may be considered as markers of disease and strong survival predictors in a variety of malignancies frequently associated to poor prognosis. Thus, the present findings are strongly advocating that exploratory clinical trials are worth to be performed, using available drugs, targeting these molecules.

Bacterial Extracellular Vesicles in Gastrointestinal Tract Cancer: An Unexplored Territory.

Simple SummaryMicrobial dysbiosis has been credited as one of the contributing factors to the development and progression of gastrointestinal tract cancer. The altered microbiota influences carcinogenesis through the induction of instability and damage to genetic material, modulation of host metabolic and inflammatory pathways, production of carcinogenic metabolites, and suppression of host antitumor response. These microbes secrete extracellular vesicles that are possibly carrying carcinogenic bioactive metabolites within their cargo. Studies have illustrated the ability of bacterial extracellular vesicles to cross the intestinal epithelial barrier and selectively accumulate near intestinal tumor cells. The purpose of this systemic review was to highlight the possible role of gut bacterial vesicles in the development, progression, and pathogenesis of gastrointestinal tract cancer and their possible involvement in the modulation of the tumor microenvironment. An infinitesimal amount of research has been carried out on the impact of bacterial extracellular vesicles on oncogenesis and tumor progression. This review aimed to encourage more investigations on this subject.Bacterial extracellular vesicles are membrane-enclosed, lipid bi-layer nanostructures that carry different classes of biomolecules, such as nucleic acids, lipids, proteins, and diverse types of small molecular metabolites, as their cargo. Almost all of the bacteria in the gut secrete extracellular vesicles to assist them in competition, survival, material exchange, host immune modulation, infection, and invasion. The role of gut microbiota in the development, progression, and pathogenesis of gastrointestinal tract (GIT) cancer has been well documented. However, the possible involvement of bacterial extracellular vesicles (bEVs) in GIT cancer pathophysiology has not been given due attention. Studies have illustrated the ability of bEVs to cross physiological barriers, selectively accumulate near tumor cells, and possibly alter the tumor microenvironment (TME). A systematic search of original published works related to bacterial extracellular vesicles on gastrointestinal cancer was performed for this review. The current systemic review outlines the possible impact of gut microbiota derived bEVs in GIT cancer in light of present-day understanding. The necessity of using advanced sequencing technologies, such as genetic, proteomic, and metabolomic investigation methodologies, to facilitate an understanding of the interrelationship between cancer-associated bacterial vesicles and gastrointestinal cancer is also emphasized. We further discuss the clinical and pharmaceutical potential of bEVs, along with future efforts needed to understand the mechanism of interaction of bEVs in GIT cancer pathogenesis.

Cancer-cell-biomimetic nanoparticles systemically eliminate hypoxia tumors by synergistic chemotherapy and checkpoint blockade immunotherapy

Checkpoint blockade-based immunotherapy has shown unprecedented effect in cancer treatments, but its clinical implementation has been restricted by the low host antitumor response rate. Recently, chemotherapy is well recognized to activate the immune system during some chemotherapeutics-mediated tumor eradication. The enhancement of immune response during chemotherapy might further improve the therapeutic efficiency through the synergetic mechanism. Herein, a synergistic antitumor platform (designated as BMS/RA@CC-Liposome) was constructed by utilizing CT26 cancer-cell-biomimetic nanoparticles that combined chemotherapeutic drug (RA-V) and PD-1/PD-L1 blockade inhibitor (BMS-202) to remarkably enhance antitumor immunity. In this study, the cyclopeptide RA-V as chemotherapeutic drugs directly killing tumor cells and BMS-202 as anti-PD agents eliciting antitumor immune responses were co-encapsulated in a pH-sensitive nanosystem. To achieve the cell-specific targeting drug delivery, the combination therapy nanosystem was functionalized with cancer cell membrane camouflage. The biomimetic drug delivery system perfectly disguised as endogenous substances, and realized elongated blood circulation due to anti-phagocytosis capability. Moreover, the BMS/RA@CC-Liposome also achieved the selective targeting of CT26 cells by taking advantage of the inherent homologous adhesion property of tumor cells. The in vitro and in vivo experiments revealed that the BMS/RA@CC-Liposome realized PD-1/PD-L1 blockade-induced immune response, RA-V-induced PD-L1 down-regulation and apoptosis in cancer cells. Such a system combining the advantages of chemotherapy and checkpoint blockade-based immunotherapy to create an immunogenic tumor microenvironment systemically, demonstrated improved therapeutic efficacy against hypoxic tumor cells and offers an alternative strategy based on the immunology of the PD-1/PD-L1 pathway.

Prognostic impact of tumor-infiltrating lymphocytes in non-small cell lung carcinomas.

Tumor-infiltrating lymphocytes represent a pivotal component of the host anti-tumor response. Thus, they considerably influence the evolution of cancers including non-small cell lung carcinomas. Even if, this important role is consensual, many discordant results are published in the literature about the prognostic role of the different populations of tumor-infiltrating lymphocytes. The aim of our work was to evaluate the prognostic impact of CD8+, CD4+, and forkhead box protein P3+ lymphocytes in the tumor microenvironment of non-small cell lung carcinomas. We conducted a retrospective descriptive study, which included non-small cell lung carcinomas diagnosed in the department of pathology and followed in the medical oncology department of the same hospital between 2011 and 2015. Tumor-infiltrating lymphocytes were analyzed by the immunohistochemical method for forkhead box protein P3, CD4, and CD8. Intratumoral and stromal-labeled lymphocytes were quantified by manual counting at high magnification (×400). Forkhead box protein P3+/CD8+, forkhead box protein P3+/CD4+, and CD8+/CD4+ ratios were subsequently calculated. The prognostic value of tumor-infiltrating lymphocytes was assessed in respect of overall survival, recurrence-free survival, and relapse-free survival. Thirty-nine patients were included. The mean age of patients was 59.6 years. A complete surgical resection (p = 0.009), and a CD8/CD4 ratio (p = 0.008) were prognostic factors for overall survival. Complete surgical resection (p = 0.003), the forkhead box protein P3/CD8 (p = 0.005), and forkhead box protein P3/CD4 (p = 0.037) ratios were prognostic factors for recurrence-free survival. The CD8+ tumor-infiltrating lymphocytes rate (p = 0.037) was a prognostic factor for relapse-free survival with a threshold of 67.8/high power field. Microscopic subtype (p = 0.037) was a prognostic factor for relapse-free survival when only adenocarcinoma and squamous cell carcinoma were considered. In multivariate analysis, age (p = 0.004) and a CD8/CD4 ratio (p = 0.016) were independent predictors of overall survival. Despite the limitations of our study, our results confirm the prognostic value of tumor-infiltrating lymphocytes in non-small cell lung carcinomas and the importance of the combined quantification of their different subpopulations.

Modulating tumor infiltrating myeloid cells to enhance bispecific antibody-driven T cell infiltration and anti-tumor response

BackgroundTumor microenvironment (TME) is a dynamic cellular milieu to promote tumor angiogenesis, growth, proliferation, and metastasis, while derailing the host anti-tumor response. TME impedes bispecific antibody (BsAb) or chimeric antigen receptor (CAR)-driven T cells infiltration, survival, and cytotoxic efficacy. Modulating tumor infiltrating myeloid cells (TIMs) could potentially improve the efficacy of BsAb.MethodsWe evaluated the effects of TIM modulation on BsAb-driven T cell infiltration into tumors, their persistence, and in vivo anti-tumor response. Anti-GD2 BsAb and anti-HER2 BsAb built on IgG-[L]-scFv platform were tested against human cancer xenografts in BALB-Rag2−/−IL-2R-γc-KO (BRG) mice. Depleting antibodies specific for polymorphonuclear myeloid-derived suppressor cell (PMN-MDSC), monocytic MDSC (M-MDSC), and tumor associated macrophage (TAM) were used to study the role of each TIM component. Dexamethasone, an established anti-inflammatory agent, was tested for its effect on TIMs.ResultsBsAb-driven T cells recruited myeloid cells into human tumor xenografts. Each TIM targeting therapy depleted cells of interest in blood and in tumors. Depletion of PMN-MDSCs, M-MDSCs, and particularly TAMs was associated with enhanced T cell infiltration into tumors, significantly improving tumor control and survival in multiple cancer xenograft models. Dexamethasone premedication depleted monocytes in circulation and TAMs in tumors, enhanced BsAb-driven T cell infiltration, and anti-tumor response with survival benefit.ConclusionReducing TIMs markedly enhanced anti-tumor effects of BsAb-based T cell immunotherapy by improving intratumoral T cell infiltration and persistence. TAM depletion was more effective than PMN- or M-MDSCs depletion at boosting the anti-tumor response of T cell engaging BsAb.

PD09-03 EXTRACELLULAR VESICLES: A MECHANISM OF ACTION OF BACILLUS CALMETTE-GUERIN AND A POTENTIAL BIOMARKER

You have accessJournal of UrologyBladder Cancer: Non-invasive I (PD09)1 Sep 2021PD09-03 EXTRACELLULAR VESICLES: A MECHANISM OF ACTION OF BACILLUS CALMETTE-GUERIN AND A POTENTIAL BIOMARKER Carlos Ortiz-Bonilla, Scott Gerber, Hiroshi Miyamoto, Edith Lord, Edward Messing, and Yi-Fen Lee Carlos Ortiz-BonillaCarlos Ortiz-Bonilla More articles by this author , Scott GerberScott Gerber More articles by this author , Hiroshi MiyamotoHiroshi Miyamoto More articles by this author , Edith LordEdith Lord More articles by this author , Edward MessingEdward Messing More articles by this author , and Yi-Fen LeeYi-Fen Lee More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000001977.03AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Extracellular vesicles (EVs), small double-membrane vesicles, have recently gained attention because of their potential roles in mediating immune responses and cancer treatments. Intravesical Bacillus Calmette-Guérin (BCG) immunotherapy is arguably one of the most successful immunotherapies for cancer, yet a significant number of patients fail response to BCG, and its underlying mechanisms remain largely unknown. In this study, we aim to test a new mode of BCG action mediated by BCG immune-active EVs (EVsBCG) released by BC cells. METHODS: Two immuno-responsive BC cell lines, human T24 and murine MB49 were used. CFU of cultured Live TICE® BCG was determined and applied on in vitro and in vivo experiments. BCG-induced immuno-molecular alteration in BC cells and EVsBCG was determined by quantitative PCR, Western blotting and Nanoparticle Tracking Analysis. EVsBCG-activated immune responses in dendritic cells were assessed by flow cytometry analyses. Moreover, we examined whether priming mice with EVsBCG can enhance BCG efficacy using the MB49 syngeneic model. The profiles of urinary EVs from BCG patients were evaluated for their predictive value. RESULTS: In response to BCG treatment, T24 and MB49 BC cells showed a significant increase in EVs secretion. EVsBCG contain elevated levels of key proteins in modulating immune responses, including MHC-I, MHC-II and CD80, CD86 co-stimulatory molecules. EVsBCG activated dendritic cells in vitro. Most importantly, priming mice with EVsBCG enhances BCG immunotherapy efficacy as compared to naïve EVs-primed mice. Interestingly, patients who respond to BCG showed significantly increased urinary EV numbers after the third BCG instillation, compared to non-responders in a pilot project. CONCLUSIONS: A novel mode of BCG action was presented. We showed that BCG promotes the release of immuno-active EVs by BC cells. Those EVsBCG can directly activate dendritic cells to modulate BCG-induced anti-tumor host response that warrants the therapeutic benefit of EVsBCG as an adjuvant therapy. Together, these data suggest that BCEVs play an important role in the mechanism of action of BCG immunotherapy. More importantly, patient-derived EVs during BCG immunotherapy may serve as predictive biomarkers. Source of Funding: HOPE Foundation, GR500600 © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e120-e120 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Carlos Ortiz-Bonilla More articles by this author Scott Gerber More articles by this author Hiroshi Miyamoto More articles by this author Edith Lord More articles by this author Edward Messing More articles by this author Yi-Fen Lee More articles by this author Expand All Advertisement Loading ...

MP66-20 BLADDER CANCER EXTRACELLULAR VESICLES: A NOVEL ANTI-TUMOR VACCINE

You have accessJournal of UrologyBladder Cancer: Basic Research & Pathophysiology III (MP66)1 Sep 2021MP66-20 BLADDER CANCER EXTRACELLULAR VESICLES: A NOVEL ANTI-TUMOR VACCINE Carlos Ortiz-Bonilla, Taylor Ucello, Scott Gerber, Hiroshi Miyamoto, Edith Lord, Edward Messing, and Yi-Fen Lee Carlos Ortiz-BonillaCarlos Ortiz-Bonilla More articles by this author , Taylor UcelloTaylor Ucello More articles by this author , Scott GerberScott Gerber More articles by this author , Hiroshi MiyamotoHiroshi Miyamoto More articles by this author , Edith LordEdith Lord More articles by this author , Edward MessingEdward Messing More articles by this author , and Yi-Fen LeeYi-Fen Lee More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002106.20AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Extracellular vesicles (EV) comprise a diverse group of small vesicles secreted by almost all types of cells into the extracellular space. EV have been shown to play crucial roles in carrying and presenting functional MHC-peptide complexes to modulate antigen-specific CD8 T cell responses. However, the therapeutic potential and immunogenicity of EV-based vaccines has not yet tested. In this project, we aim to investigate the potential of using bladder cancer (BC) EV as a cancer vaccine in a pre-clinical model. METHODS: EV derived from murine MB49 BC cells were characterized by Nanoparticle Tracking Analysis, and EV cargo proteins and encapsulated cytokines were analyzed by Mass Spectrometry and pro-inflammatory cytokine array. The anti-tumor immunity of BCEV was evaluated in the MB49 syngeneic mouse model where mice were primed with MB49 EV prior MB49 tumors inoculation. Tumor growth was monitored and tumor-infiltrated immune cell populations were determined by flow cytometry. Anti-CD8 neutralizing antibody as well as IgG isotype control antibody were administrated to mice to test whether BCEV-mediated anti-tumor immunity is dependent on CD8 T cells. Moreover, we determined whether priming mice with MB49EV can prevent colonization of un-related colon MC-38 tumors in vivo. RESULTS: Proteomic and cytokine array analysis have revealed that MB49 EV encapsulated enriched immuno-active cargo proteins and cytokines with function linked to both innate and adaptive immune responses. To our surprise, priming mice with MB49 EV completely prevented MB49 tumor growth in vivo and neutralizing CD8 T cells abolished the MB49 EV-mediated anti-tumor effect. Interestingly, MB49 EV priming was unable to prevent MC-38 tumor growth but hindered significantly their growth in vivo. Flow cytometry analyses revealed increased levels of tumor-infiltrated granulocytes, inflammatory monocytes, and natural killer cells in EV-primed MC-38 tumors. In addition, those tumors also showed increased numbers of infiltrated antigen-presenting dendritic cells and antigen-specific CD4 and CD8 T cells. CONCLUSIONS: For the first time, we provided direct in vivo evidence that BCEV can prevent isogenic tumor growth, and such action is mainly mediated by CD8 T cells. They encapsulated enriched immunogenic cargo proteins and cytokines that could even promote anti-tumor host response against unrelated tumor growth. In summary, our study support the potential application of tumor-derived EV in personalized medicine, and open new avenue for developing therapeutic cancer vaccine based on patient-derived EV to prevent BC recurrence. Source of Funding: NCI RO1 CA173986 © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e1137-e1137 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Carlos Ortiz-Bonilla More articles by this author Taylor Ucello More articles by this author Scott Gerber More articles by this author Hiroshi Miyamoto More articles by this author Edith Lord More articles by this author Edward Messing More articles by this author Yi-Fen Lee More articles by this author Expand All Advertisement Loading ...

Abstract 828: Common genetic variants influence the composition of the tumor immune microenvironment and host anti-tumor responses

Abstract Developing effective therapies to intervene in the tumor immune evasion process is a challenge further complicated by interindividual variability in tumor-host immunological interactions. Germline variation is a major component of interindividual variability usually studied by large-scale genome-wide association studies (GWAS) in the context of disease risk; yet, there is still a gap in our understanding of germline variation specifically in the tumor immune microenvironment. To address this, we systematically characterized the immune effects of germline genetic polymorphisms across 33 human cancer types in the TCGA. Immune microenvironment phenotypes include immune infiltration levels as calculated by CIBERSORTx and expression of immunomodulator genes obtained through literature curation. PCA analysis reduced dimensionality of immune phenotypes, with macrophage regulation and EP300/Proteosome expression mediating most variability amongst individuals. We identified 482 SNP-immune gene associations, where a subset of SNPs affected multiple immune phenotypes. Using cell-type and epigenetic analyses, we further characterized immune microenvironment variants to act through macrophage and dendritic cell-specific manners and alter immune-cell specific epigenetic regions. Through burden analysis, we found several of these variants interact to have stronger immune microenvironment effects. Lastly, using ICB-trial cohorts, we found several variants affecting LILRB2, LILRB4, LAIR1, CCBL2, and CTSW modulate response to immune checkpoint blockade. Our results provide better understanding of how germline variation modifies tumor immune microenvironment dynamics and will set up further studies to identify predictive biomarkers of the tumor immune microenvironment. Citation Format: Meghana Pagadala, Hyo Kim, Andrea Castro, Cristian Gonzalez-Colin, Victoria Wu, Steven Cao, Benjamin Schmiedel, Rany Salem, Silvio Gutkind, Wes Thompson, Vijayanand Pandurangan, Hannah Carter. Common genetic variants influence the composition of the tumor immune microenvironment and host anti-tumor responses [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 828.

Axl and Mertk Receptors Cooperate to Promote Breast Cancer Progression by Combined Oncogenic Signaling and Evasion of Host Antitumor Immunity.

Despite the promising clinical benefit of targeted and immune checkpoint blocking therapeutics, current strategies have limited success in breast cancer, indicating that additional inhibitory pathways are required to complement existing therapeutics. TAM receptors (Tyro-3, Axl, and Mertk) are often correlated with poor prognosis because of their capacities to sustain an immunosuppressive environment. Here, we ablate Axl on tumor cells using CRISPR/Cas9 gene editing, and by targeting Mertk in the tumor microenvironment (TME), we observed distinct functions of TAM as oncogenic kinases, as well as inhibitory immune receptors. Depletion of Axl suppressed cell intrinsic oncogenic properties, decreased tumor growth, reduced the incidence of lung metastasis and increased overall survival of mice when injected into mammary fat pad of syngeneic mice, and demonstrated synergy when combined with anti-PD-1 therapy. Blockade of Mertk function on macrophages decreased efferocytosis, altered the cytokine milieu, and resulted in suppressed macrophage gene expression patterns. Mertk-knockout mice or treatment with anti-Mertk-neutralizing mAb also altered the cellular immune profile, resulting in a more inflamed tumor environment with enhanced T-cell infiltration into tumors and T-cell-mediated cytotoxicity. The antitumor activity from Mertk inhibition was abrogated by depletion of cytotoxic CD8α T cells by using anti-CD8α mAb or by transplantation of tumor cells into B6.CB17-Prkdc SCID mice. Our data indicate that targeting Axl expressed on tumor cells and Mertk in the TME is predicted to have a combinatorial benefit to enhance current immunotherapies and that Axl and Mertk have distinct functional activities that impair host antitumor response. SIGNIFICANCE: This study demonstrates how TAM receptors act both as oncogenic tyrosine kinases and as receptors that mediate immune evasion in cancer progression.

Programmed death 1 ligand (PD-L1) in solid cancers after allogeneic hematopoietic stem cell transplantation: a retrospective analysis by the Nagasaki Transplant Group.

Programmed death 1 ligand (PD-L1) is an immunomodulatory molecule expressed by cancer cells, and it has been widely demonstrated to inhibit host antitumor responses. The aim of the present study was to identify clinicopathological features associated with PD-L1 expression in the secondary solid cancers of patients after allogeneic hematopoietic stem cell transplantation. In this database of 530 patients who received allo-HSCT between 1990 and 2017, 15 developed solid cancers with a median interval of 3487days after transplantation. Three patients had 2 different solid cancers. Eighteen solid cancer cases were identified. A multivariate analysis showed that chronic graft-versus-host disease (GVHD) was associated with an increased risk of solid cancer. The presence of chronic GVHD was observed in 8 out of 18 cases at the diagnosis of secondary malignancies. PD-L1 expression levels in cancers were significantly higher in patients with active chronic GVHD than in those without chronic GVHD (P = 0.020). Five cases of cancer that developed in the involved organs of chronic GVHD showed 30% or higher PD-L1 positivity. The present results revealed distinct PD-L1 expression in the secondary solid cancers of post-transplant patients with chronic GVHD.