Higher Tumor Infiltration Research Articles

Abstract 1871: Discovery and characterization of NXV01c, an EGFR × cMET bispecific nanobody drug conjugate with potent anti-tumor activity

Abstract EGFR and cMET are proven cancer targets co-expressed in diverse tumor types. EGFR × cMET bispecific antibody has been approved for the treatment of NSCLC, supporting a simultaneous targeting strategy. In addition to this dual targeting benefit, bispecific antibody drug conjugates (ADCs) targeting EGFR and cMET have also been developed to further improve anti-tumor activity and tissue selectivity. Sufficient target affinity, good cellular internalization and high tumor infiltration are critical for an ADC to mediate therapeutic activity. To this end, we developed the first EGFR × cMET bispecific nanobody conjugated with monomethyl auristatin E (MMAE) as payload (NXV01c). Lead nanobodies against EGFR and cMET were respectively selected from immune libraries by phage display, followed by highly efficient humanization and optimization by neoX’s computation platform. The bispecific nanobody with Fc (NXV01) was constructed by “knobs-into-holes” heterodimerization and then homogeneously conjugated with MMAE via a lysosomal cleavable valine-citrulline dipeptide linker. The resulting bispecific nanobody drug conjugate (NDC), NXV01c, was evaluated in multiple tumor cell lines and tumor xenograft models. NXV01, the pre-conjugate bispecific nanobody, bound EGFR and cMET with nanomolar potency (BLI) and inhibited the phosphorylation of cellular EGFR and cMET with nanomolar IC50 (ELISA). Moreover, it did not activate cellular cMET. Importantly, the NDC NXV01c is highly homogeneous: it has an average DAR of 3.87 and >95% of NXV01c has a DAR of 4. To examine stability of conjugation, NXV01C was incubated in human plasma (37°C) for 14 days, the maximum free drug release rate (by LC/MS/MS) is 0.68%, which is much lower than that of DS8201. In vitro, NXV01c was rapidly internalized into H1975 cells which co-expressed EGFR and cMET. It inhibited the growth of H1975 (lung) and SNU5 (gastric) cancer cells with picomolar activity but spared normal keratinocytes. NXV01c also inhibited the proliferation of additional cell lines derived from lung, gastric, esophageal, and liver cancer, and the level of inhibition positively associated with the expression density of both targets. In an H1975 cell line-derived xenograft model, NXV01C exhibited potent and dose-dependent anti-tumor activity. Treatments at 3 and 10 mg/kg once per week for 2 weeks led to shrinkage and complete regression of tumor, respectively. In patient-derived xenograft models of NSCLC and esophageal cancer, NXV01C led to tumor regression and elimination without noticeable toxic effects. EGFR × cMET bispecific nanobody drug conjugate NXV01c has favorable drug-like properties and demonstrated superior anti-tumor effect in vitro and in vivo. The results suggest NXV01C can be an effective solution for EGFR/cMET bearing tumors commonly found in diverse malignancies. Citation Format: Ran Wu, Puwei Yuan, Yang Xie, Jianxiu Guo, Fei Zhang, Fan Liu, Taylor B. Guo. Discovery and characterization of NXV01c, an EGFR × cMET bispecific nanobody drug conjugate with potent anti-tumor activity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1871.

Single-cell combined bioinformatics analysis: construction of immune cluster and risk prognostic model in kidney renal clear cells based on CD8+ T cell-associated genes

BackgroundKidney cancer is an immunogenic solid tumor, characterized by high tumor burden and infiltration of CD8+ T cells. Although immunotherapy targeting the PD1/CTLA-4 axis has demonstrated excellent clinical efficacy, clinical outcomes in most patients are poor.MethodsWe used the RNA sequencing data from the GEO database for KIRC GSE121636 and normal kidney tissue GSE131685, and performed single-cell analysis for cluster identification, pathway enrichment, and CD8+ T cell-associated gene identification. Subsequently, the significance of different CD8+ T-cell associated gene subtypes was elucidated by consensus clustering, pathway analysis, mutated gene analysis, and KIRC immune microenvironment analysis in the TCGA–KIRC disease cohort. Single gene analysis identified LAG3 as the most critical CD8+ T-cell-associated gene and its function was verified by cell phenotype and immunohistochemistry in KIRC.ResultsIn the present study, CD8+ T-cell associated genes in KIRC were screened, including GZMK, CD27, CCL4L2, FXYD2, LAG3, RGS1, CST7, DUSP4, CD8A, and TRBV20-1 and an immunological risk prognostic model was constructed (risk score = − 0.291858656434841*GZMK − 0.192758342489394*FXYD2 + 0.625023643446193*LAG3 + 0.161324477181591*RGS1 − 0.380169045328895*DUSP4 − 0.107221347575037*TRBV20-1). LAG3 was identified and proved as the most critical CD8+ T cell-associated gene in KIRC.ConclusionWe proposed and constructed an immunological risk prognostic model for CD8+ T cell-associated genes and identified LAG3 as a pivotal gene for KIRC progression and CD8+ T-cell infiltration. The model comprehensively explained the immune microenvironment and provided novel immune-related therapeutic targets and biomarkers in KIRC.

Prognostic Impact of CD38- and IgκC-Positive Tumor-Infiltrating Plasma Cells in Triple-Negative Breast Cancer.

Due to a higher mutational load, triple-negative breast cancer (TNBC) is characterized by a higher immunogenicity compared to other subtypes. In this context, we analyzed the prognostic significance of tumor-infiltrating plasma cells in a cohort of 107 triple-negative breast cancer patients. Tumor-infiltrating plasma cells were analyzed via immunohistochemistry using the plasma cell markers CD38 and IgκC. The prognostic impact of the CD38 and IgκC expression was evaluated using the Kaplan-Meier plots and Cox regression analyses. A Spearman-Rho correlation coefficient was used to evaluate a possible association between plasma cell infiltration and the BRCA mutation status. The study cohort consisted of 107 patients with early-stage TNBC, who were treated between 2009 and 2016 at the Department of Gynecology and Obstetrics, University Medical Center Mainz, Germany. The median follow-up was five years. The Kaplan-Meier survival analysis showed that higher tumor infiltration with CD38-positive plasma cells was associated with significantly longer metastasis-free survival (MFS) (p = 0.039 Log Rank). In the multivariate Cox regression analysis for metastasis-free survival, in which additional clinicopathological factors (age, tumor size, nodal status, and grading) were considered, CD38 was identified as an independent prognostic factor within the analyzed cohort (HR 0.438, 95% CI 0.195-0.983; p = 0.045). In addition to the CD38 expression, the nodal status was also identified as an independent prognostic factor in multivariate Cox regression. Regarding the IgκC expression, a higher IgκC expression was shown to be associated with a better outcome, although this effect was not statistically significant. Furthermore, we were able to show a significant correlation between plasma cell infiltration and the BRCA mutation status. A favorable prognostic significance of tumor-infiltrating plasma cells could be demonstrated in triple-negative breast cancer immunohistochemically analyzed for the CD38 and IgκC expression. CD38 was identified as an independent prognostic factor via multivariate Cox regression.

DNA mismatch repair in cancer immunotherapy.

Tumors defective in DNA mismatch repair (dMMR) exhibit microsatellite instability (MSI). Currently, patients with dMMR tumors are benefitted from anti-PD-1/PDL1-based immune checkpoint inhibitor (ICI) therapy. Over the past several years, great progress has been made in understanding the mechanisms by which dMMR tumors respond to ICI, including the identification of mutator phenotype-generated neoantigens, cytosolic DNA-mediated activation of the cGAS-STING pathway, type-I interferon signaling and high tumor-infiltration of lymphocytes in dMMR tumors. Although ICI therapy shows great clinical benefits, ∼50% of dMMR tumors are eventually not responsive. Here we review the discovery, development and molecular basis of dMMR-mediated immunotherapy, as well as tumor resistant problems and potential therapeutic interventions to overcome the resistance.

Abstract 4707: LED photobleaching-based multiplex 3D microscopy of the tumor microenvironment

Abstract Multiplexing in immunofluorescence imaging is important for the spatial profiling of cells and molecules in tumor tissue samples. Cyclic immunofluorescence (IF) methods using oxidants (e.g. hydrogen peroxide) and enzymes (e.g. DNase) localize a great number of cellular makers and proteins in a tissue section while repeating a process of IF staining, imaging, and fluorescence deactivation. However, the repeated use of chemicals and enzymes might cause artifacts in tissue and cell morphologies. Furthermore, these methods are restricted to thin tissue sections (~5 μm thick) which are inappropriate to provide comprehensive structural information on tissue samples. Although reconstruction of two-dimensional (2D) images from serial tissue sections can provide a certain volumetric tissue image, it takes a huge amount of time and effort. Here we introduce a three-dimensional (3D) multiplex IF imaging method using LED photobleaching. We built high-power LED illuminators with 100W warm (emission wavelength: 480-700 nm), green (430-520 nm), and red (600- 680 nm) LED chips, which can efficiently bleach a broad or selected wavelength of fluorescence signals in tissue samples. We integrated this LED photobleaching with the Transparent Tissue Tomography (T3) protocol and created a 3D cyclic IF method involving tissue macrosectioning (400 μm), three-color IF staining, D-fructose-based tissue clearing, 3D confocal fluorescence microscopy, LED photobleaching, tissue washing, and three-color IF staining for other biomarkers, and repeating the process. By applying this method to mouse mammary tumor tissues, we could perform 8-plex fluorescence microscopy for visualizing cell nuclei (DAPI), vascular (CD31, SMA) and structural (ER-TR7) cells, immune cells (CD3, CD8, CD45), and cancer cells (CK8) in the tumor macrosections in 3D at tissue and cellular resolution. To validate the method as an evaluation tool for immunotherapy, we treated the mouse mammary tumor with a STING agonist (DMAXX) intratumorally and collected the tumor tissue 1 day after the treatment, and processed it for the 3D cyclic IF protocol. The quantitative multiplex image data showed immune-driven-cancer eradication and high tumor infiltration of a large number of CD3+CD8+CD45+ cytotoxic T cells. We also examined that Red and Green LED illumination can selectively bleach fluorophores in tissues, which would be useful for patterning fluorescence in tissue as well as studying fluorescent drug-cell interaction in a tissue. In summary, this chemical and enzyme-free 3D cyclic IF imaging method will be a powerful tissue assay tool to provide comprehensive spatial information of tissue (tumor) samples including cell types, cellular and molecular location, and their 3D organization in a tissue sample. Citation Format: Jingtian Zheng, Evan Phillips, Yi-Chien Wu, Steve Seung-Young Lee, Vytautas Bindokas. LED photobleaching-based multiplex 3D microscopy of the tumor microenvironment. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4707.

Spatial genomics reveals a high number and specific location of B cells in the pancreatic ductal adenocarcinoma microenvironment of long-term survivors.

Only 10% of pancreatic ductal adenocarcinoma (PDAC) patients survive longer than five years. Factors underlining long-term survivorship in PDAC are not well understood. Therefore, we aimed to identify the key players in the tumor immune microenvironment (TIME) associated with long-term survivorship in PDAC patients. The immune-related gene expression profiles of resected PDAC tumors of patients who survived and remained recurrence-free of disease for ≥36 months (long-term survivors, n=10) were compared to patients who had survived ≤6 months (short-term survivors, n=10) due to tumor recurrence. Validation was performed by the spatial protein expression profile of immune cells using the GeoMx™ Digital Spatial Profiler. An independent cohort of samples consisting of 12 long-term survivors and 10 short-term survivors, was used for additional validation. The independent validation was performed by combining qualitative immunohistochemistry and quantitative protein expression profiling. B cells were found to be significantly increased in the TIME of long-term survivors by gene expression profiling (p=0.018). The high tumor infiltration of B cells was confirmed by spatial protein profiling in the discovery and the validation cohorts (p=0.002 and p=0.01, respectively). The higher number of infiltrated B cells was found mainly in the stromal compartments of PDAC samples and was exclusively found within tumor cells in long-term survivors. This is the first comprehensive study that connects the immune landscape of gene expression profiles and protein spatial infiltration with the survivorship of PDAC patients. We found a higher number and a specific location of B cells in TIME of long-term survivors which emphasizes the importance of B cells and B cell-based therapy for future personalized immunotherapy in PDAC patients.

Immune Profiling of MM Microenvironment at Single-Cell Resolution

Background: The survival of multiple myeloma (MM) is highly dependent on the support of immune microenvironment. However, it is still a challenge to enhance the efficacy of immunotherapy and the underlying mechanism remains obscure. Thus, the aim of our study is to investigate into the dysfunction of immune cells associated with myelomagenesis and figure out the novel immunotherapeutic targets. Method: Single-cell RNA sequencing was utilized for bone marrow mononuclear cells of 7 healthy donors and 12 newly diagnosed MM patients. We analyze the various immune cell populations and their interaction network with tumor cells of NDMM patients by single-cell RNA sequencing data. Results: Firstly, we found a significant negative correlation between the proportion of T/NK cells and tumor burden. Especially, we observed a decrease of CD8+ effector T cells and skewed accumulation of CD8+ memory T cells in patients with high tumor burden. Further, via calculating the cytotoxicity and exhaustion score of T cells, we demonstrated that the dysfunction of CD8+ effector T cells is mostly related with the impaired cytotoxicity, but not the expression of classical exhausted genes, such as CTLA4, VSIR, LAG3, etc. PIM kinases PIM2/3 and KLRB1 seemed to play critical roles in the dysfunction of CD8+ effector T cells. Referring to NK cells, NK cells displayed similar pattern with effector T cells. NK cells also presented decreased cytotoxicity score in patients with high tumor burden and increased expression of PIM1 and KLRC1, which contributed to immunosuppression. Next, we investigated into myeloid compartment of MM patients. Conventional DC (cDC) cells expressed low level of genes including HLA-B, HLA-C, HLA-DRB1, and HLA-DQA1, etc., indicating the impaired antigen presentation by DCs in high-tumor-burden condition. By cell contact analysis, we evaluated the immune crosstalk among immune cells and tumor cells. We indicated the core role of myeloid cells in MM microenvironment. Consistently, the cellular interaction was active in low-tumor-burden condition, whereas suppressed in high-tumor-burden condition. Finally, we examined the metabolic status of immune cell of MM patients to elucidate the underlying mechanisms of dysfunction of immune cells. Our analysis suggested that aberrant metabolism including amino acid metabolism, lipid metabolism, oxidative phosphorylation caused by MM cells were involved in the defective immune response in MM. Conclusion: Our study delineated the immune profile of bone marrow in MM. We suggested an immunosuppressive microenvironment impacted by high tumor infiltration. The serine/threonine kinase PIM family were involved in the dysfunction of both innate and adaptive immune response. Reprogramming immune metabolism proved to be a hopeful immunotherapeutic strategy.

WIN Symposium 2022 - Abstract Poster Presentations.

WIN Symposium 2022 - Abstract Poster Presentations.

Tumor HPV Status, Level of Regulatory T Cells and Macrophage Infiltration Predict up to 20-Year Non-Disease-Specific Survival in Oropharynx Squamous Cell Carcinoma Patients.

Oropharynx squamous cell carcinoma (OPSCC) is of special interest because human papilloma virus (HPV) and/or smoking cause this disease. Influxes of inflammatory cells into such tumors are known to vary with prognoses. Aims: To study whether the density of tumor-infiltrating T lymphocytes and tumor-infiltrating macrophages predicted general 20-year overall survival (OS), as well as OS with only disease-specific survival (DSS) patients included. Methods: Biopsies from patients treated for OPSCC (n = 180) were stained by immunohistochemistry and the tumor cell macrophage (CD68), pan T lymphocytes (CD3), and regulatory T lymphocytes (Foxp3) densities were determined. The HE-determined percentage of matured tumor cells and the rate of invasion were calculated, and stromal desmoplasia were performed. Tumor HPV presence was studied by PCR. Twenty-year OS and five-year DSS patients were determined. Results: Tumor HPV status strongly predicted survival. High tumor infiltration of CD3, Foxp3 and CD68-positive cells predicted better twenty-year OS, with and without HPV stratification. Foxp3 and CD68 levels predicted OS, and 20-year among DSS patients, primarily among HPV(+) patients. Tumor HE-derived variables did not predict such survival. Conclusions: Tumor HPV status, level of Foxp3 tumor-infiltrating lymphocytes and CD68 tumor-infiltrating macrophages predicted up to 20-year OS of both all patients and disease-specific survived patients.

FGF/FGFR-related lncRNAs based classification predicts prognosis and guides therapy in gastric cancer.

Fibroblast growth factor (FGF) and its receptor (FGFR) play crucial roles in gastric cancer (GC). Long non-coding RNAs (lncRNAs) are defined as RNA molecules of around 200 nucleotides or more, which are not translated into proteins. As well-known regulatory factors, lncRNAs are considered as biomarkers for prognosis and treatment response in GC. It is of importance to identify FGF/FGFR-related lncRNAs in GC. Here, some FGF/FGFR-related lncRNAs were identified in GC based on the data from public databases, the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO). Then a four-lncRNAs (FGF10-AS1, MIR2052HG, POU6F2-AS2, and DIRC1) risk score (RS) model was established for predicting GC’s prognosis by using Cox analysis. According to the median value of RS, GC patients were divided into low and high RS group. Low RS group displayed high tumor mutation burden and infiltration of immune cells, as well as more sensitivity to immunotherapy or chemotherapy. High RS group showed high infiltration of stromal cells and more oncogenic signatures. In addition, a comprehensive analysis was carried out and found that high RS group may exhibit specific sensitivity to Panobinostat (histone deacetylases inhibitor) and Tivantinib (MET inhibitor). In summary, our study not only offers a novel personalized prognostication classification model according to FGF/FGFR-related lncRNAs, but also provides a new strategy for subclass-specific precision treatment in GC.

Factors affecting prognosis in signet ring cell gastric cancers with expanded lymph node dissection; high volume centre experience

Background: Signet ring cell gastric cancer differs from gastric adenocarcinoma in terms of demographic and clinical features, age, gender, tumour grade and stage. In this study, we aimed to evaluate the clinical features and overall survival of gastric signet ring cell carcinoma and the prognostic factors affecting survival.Methods: We analysed 138 patients who were operated on with the diagnosis of signet ring cell gastric cancer. The univariant and multivariate hazard ratios of these parameters were analysed and the factors affecting the long-term average survival outcomes were investigated.Results: We performed Cox regression univariate analysis to investigate the effects of clinicopathological factors on mean survival follow-up in signet ring cell gastric cancer. As age increases, the mean survival follow-up period decreases. This relationship is also statistically significant. Mean survival follow-up for the open technique was lower than for laparoscopic procedures. The mean survival follow-up time of patients with positive perineural invasion (PNI) and lymphovascular invasion (LVI) is lower than patients with negative LVI and PNI. We did not find a significant relationship between the hazard ratios (HRs) of tumour markers and systemic inflammatory response parameters. However, we found a significant relationship between the increase in fibrinogen value and HR.Conclusions: We investigated the clinicopathological features of nonmetastatic signet ring cell gastric carcinomas and identified predictors of long survival. Age, lymphovascular and perineural invasion, open surgery, higher tumor infiltration, and lymph node involvement were independent predictors of shorter survival times in nonmetastatic signet ring cell gastric cancers.

Abstract 622: Development and characterization of a novel anti-PD1 resistant sarcoma mouse model

Abstract Background: Soft Tissue Sarcoma (STS) is known to be resistant to cancer immunotherapy including the prototypical immune checkpoint inhibitor (ICI) anti-PD1 (1). It’s therefore crucial to develop innovative strategies aiming at improving current clinical benefit. To this end, a well-characterized sarcoma preclinical model that mimics resistance to immunotherapy is needed. Starting from the anti-PD(L)1-sensitive MCA205 sarcoma mouse model, we therefore aimed at developing and characterizing a novel model resistant to anti-PD1. Methods: Anti-PDL1 antibody was first administered to the ICI-sensitive MCA205 mouse sarcoma model (MCA205-S) and tumor growth was followed overtime. Tumor from a “non-responder” animal - tumor growth profile being similar as in the vehicle group - was then retrieved and processed for tissue dissociation and cell culture. Tumor cells were then amplified and inoculated into immunocompetent C57BL/6 mice that were exposed or not to anti-PD1 antibody, and tumor growth was monitored for a 8-week period. In addition, tumor samples from satellite animals were collected and processed for intratumoral immune landscape characterization by multiparametric flow cytometry as well as for gene expression analysis by RNA sequencing. Results: While anti-PD1 antibody demonstrated a strong anti-tumor effect in MCA205-S tumor-bearing mice, administration of anti-PD1 to the mice inoculated with the non-responder mouse-originating MCA205 cells did not yield to a significant anti-tumor effect thereby validating the resistant profile of this new MCA205-R cell line. Flow cytometry analysis of tumor-infiltrated immune cells revealed a higher abundance of macrophages (defined as CD11b+/F4:80+) in MCA205-R when compared to the MCA205-S model, which more likely harbor a M2 phenotype. Also, anti-PD1 treatment favored an important MCA205-R tumor infiltration by gMDSC which was more limited in the MCA205-S model. Gene expression profile of tumor samples is currently under investigation. Conclusions: We developed and validated a novel preclinical mouse model of sarcoma (MCA205-R) characterized by its resistance to anti-PD1 and a high tumor infiltration by macrophages. This model - more reflecting the clinic in terms of immunotherapy sensitivity - can thus serve to evaluate novel immunotherapeutic regimens either alone or in combination with reference ICI, to ultimately translate into clinical benefit for STS patients treated with immunotherapy. Citation Format: Imane Nafia, Jean-Philippe Guegan, Assia Chaibi, Noëlie Bos, Doriane Bortolotto, Christophe Rey, Loïc Cerf, Florent Peyraud, Antoine Italiano, Alban Bessede. Development and characterization of a novel anti-PD1 resistant sarcoma mouse model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 622.

Role of CTLA4 immunohistochemistry in the diagnosis of colon cancers.

There are a wide range of diagnostic markers for colorectal cancers like detection of mutated KRAS, TP53, and APC genes. However, genetic and immunological factors have also been attributed to the cancer prognosis. The present study was carried out to evaluate the expression of CTLA-4 in colorectal cancers. This cross-sectional study was carried out among 30 resected specimens of colorectal cancer. Paraffin blocks were made on samples from tumor areas along with adjacent normal areas. Immunohistochemistry for CTLA-4 was done on the sections along with controls. Gross findings were recorded from the blocks. Blocks with section containing normal epithelium and tumor were chosen for immunohistochemistry. Overexpression of CTLA-4 was observed in 43.3% of the tumors. There was a significantly high tumor infiltration among those specimens showing overexpression of CTLA-4. The observed difference was statistically significant (P < 0.05). On comparing the grade of the tumor with intensity of CTLA4 uptake, it was observed that majority of the well-differentiated tumors (66.7%) had an intensity of 1+ whereas majority of the poorly differentiated tumors had an intensity of 3+ (66.7%). The present study has demonstrated overexpression of CTLA-4 in colorectal cancer specimens, and also highlighted the potential scope for anti-CTLA-4 agents like Ipilimumab in cancer therapy. The need for further evaluation to examine five-year survival with such immunotherapies is essential to document candid therapeutic recommendations for colorectal cancers.

Low Tumor Infiltrating Mast Cell Density Reveals Prognostic Benefit in Cervical Carcinoma.

Objectives: Research on the role of mast cells (MCs) in cervical tumor immunity is more limited. Therefore, our study aimed to evaluate the prognostic value of MCs and their correlation with the immune microenvironment of cervical carcinoma (CC). Methods: The Cancer Genome Atlas (TCGA) data was utilized to obtain the degree of immune infiltration of MCs in CC. Meanwhile, this study retrospectively collected patient clinical characteristic data and tissue specimens to further verify the relevant conclusions. Mast cell density (MCD) was measured by the CIBERSORT algorithm in TCGA data and immunohistochemical staining of tryptase in CC tissues. Finally, differentially expressed genes (DEGs) of TCGA data were performed using “limma” packages and key gene modules were identified using the MCODE application in Cytoscape. Results: The results showed MCs were diffusely distributed in CC tissues. Moreover, we found that low tumor-infiltrating MCD was beneficial for overall survival (OS) in the TCGA cohort. Consistent conclusions were also obtained in a clinical cohort. In addition, a total of 305 DEGs were analyzed between the high tumor-infiltrating MCD and low tumor-infiltrating MCD group. Seven key modules, a total of 34 genes, were screened through the MCODE plug-in, which was mainly related to inflammatory response and immune response and closely correlated with cytokines including CSF2, CCL20, IL1A, IL1B, and CXCL8. Conclusion: In short, high tumor-infiltration MCs in CC tissue was associated with worse OS in patients. Furthermore, MCs were closely related to cytokines in the tumor microenvironment, suggesting that they collectively played a role in the immune response of the tumor. Therefore, MCD may be a potential prognostic indicator and immunotherapy target of CC.

Abstract PO-118: The tumor immune microenvironment is decisive in the survival of pancreatic ductal adenocarcinoma

Abstract Background: Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy associated with a poor prognosis. Only 10% of the patients survive longer than five years. So far, factors underlining long-term survivorship in PDAC are not well understood. Therefore, we aimed to identify the key players in the tumor immune microenvironment (TIME) associated with long-term survivorship in PDAC patients. Methods: The immune-related gene expression profiles of surgically resected PDAC tumors of patients who survived and remained recurrence-free of disease for &amp;gt; 3 years (long-term survivors, n=10) were compared to PDAC tumors of patients who had survived ≤ 6 months (short-term survivors, n=10) due to tumor recurrence. Samples were profiled using the nCounter® PanCancer Immune Profiling Panel of NanoString Technology. Validation was performed by spatial analysis of immune cells using the GeoMx™ Digital Spatial Profiler. Results: Tumor-infiltrating B cells were found to be significantly increased in the TIME of long-term survivors by gene expression profiling (p=0.018). The high tumor infiltration of B cells was confirmed by spatial protein profiling (p=0.049). This increase was accompanied by more T cells and antigen-presenting cell infiltration. Moreover, the activated immune cells were found to infiltrate in between tumor cells as well as in stromal areas in long-term survivors. In contrast, the TIME of short-term survivors was characterized by a high density of immunosuppressive cells like CD25 and regulatory T cells infiltrating in a highly fibrotic vicinity. Conclusion: This is the first comprehensive study that connects the immune landscape of gene expression profiles and protein spatial infiltration with the survivorship of PDAC patients. We found higher infiltration of B cells in TIME of long-term survivors which highlights the importance of targeting B cells and B cell-based therapy for future personalized immunotherapy in PDAC patients. Citation Format: Hosein M. Aziz, Lawlaw Saida, Willem de Koning, Andrew Stubbs, Yunlei Li, Casper H. J. van Eijck, Dana A. M. Mustafa. The tumor immune microenvironment is decisive in the survival of pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2021 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2021;81(22 Suppl):Abstract nr PO-118.

Kinase Inhibitors' Effects on Innate Immunity in Solid Cancers.

Simple SummaryIn this review, we evaluate the updated data of the immunological effects of kinase inhibitors on the innate immune system and provide an in-depth analysis of the underlying mechanisms. We also discuss how this immunological effect can be harnessed to improve cancer treatment and highlight recent successes, such as the combination with anti-tumor immunotherapy. Last, we explore novel kinase targets and the incorporation of them with targeted drug delivery techniques as promising research areas.Innate immune cells constitute a plastic and heterogeneous cell population of the tumor microenvironment. Because of their high tumor infiltration and close interaction with resident tumor cells, they are compelling targets for anti-cancer therapy through either ablation or functionally reprogramming. Kinase inhibitors (KIs) that target aberrant signaling pathways in tumor proliferation and angiogenesis have been shown to have additional immunological effects on myeloid cells that may contribute to a protective antitumor immune response. However, in patients with malignancies, these effects are poorly described, warranting meticulous research to identify KIs’ optimal immunomodulatory effect to support developing targeted and more effective immunotherapy. As many of these KIs are currently in clinical trials awaiting approval for the treatment of several types of solid cancer, we evaluate here the information on this drug class’s immunological effects and how such mechanisms can be harnessed to improve combined treatment regimens in cancer.

Dysregulation of Epigenetic Landscape Uncovered the Mechanisms Underlying the Relapse of Pediatric Acute Lymphoblastic Leukemia with NSD2 Mutation

Background: Relapse from acute lymphoblastic leukemia (ALL) is one of the most common causes of pediatric cancer-related death. Early relapse of ALL is associated with recurrent mutations of histone methyltransferase NSD2 (nuclear receptor binding SET domain protein 2), which is specific for H3K36me2, suggesting a link to therapy resistance or other mechanisms underlying relapse such as central neural system (CNS) infiltration. NSD2 p.E1099K affects gene expression through disturbing the balance of H3K36me2/H3K27me3. Using CRISPR/Cas9-edited isogenic ALL cell lines and PDX cells, we found that NSD2 p.E1099K drives oncogenic programming, CNS infiltration and glucocorticoid (GC) resistance. However, the molecular mechanisms underlying the relapse of this subtype of ALL are still under investigation.Aim: To elucidate the epigenetic landscape underlying the mechanism of the relapse of pediatric ALL with NSD2 mutation.Methods: We performed in vivo experiments to observe tumor burden, leukemia cell infiltration and survival of the NOD/SCID mice injected with a NSD2 p.E1099K mutation knock-out SEM cell line and knock-in CEM cell line. We determined transcriptome (RNA-Seq), chromatin accessibility (ATAC-Seq) in isogenic RCH-ACV, SEM, RPMI-8402 and CEM cell lines, transcription factor binding and histone modification (ChIP-Seq) and 3D organization (Hi-C) in RCH-ACV cells. Finally, we integrated analysis of RNA-Seq, ATAC-Seq, ChIP-Seq and Hi-C to comprehensively disclose the epigenetic landscape in ALL with NSD2 mutation.Results: NOD/SCID mice xenografted with NSD2 mutant cells developed high tumor burden and infiltration to spleen, liver and brain while the mice injected with WT cells accumulated significant less tumor cells and had extended survival. RNA-Seq analysis showed that reversion of NSD2 mutation to WT caused more genes downregulated while insertion of NSD2 mutation to WT cells led to more genes upregulated (Mutant vs WT: RCH-ACV 838 vs 494, SEM 1567 vs 1158, RPMI-8402 1922 vs 1745, CEM 1809 vs 1031). 50 upregulated genes and 3 downregulated genes were in common in B-ALL and T-ALL with NSD2 mutation. Most of the upregulated genes correlated with neural development and adhesion which might contribute to CNS infiltration (e.g., NCAM1 and NEO1). A few genes were associated with GC resistance such as decreased NR3C1 and increased NR3C2. Accordingly, ATAC-Seq showed that NSD2 mutant cells had more open chromatin peaks than those of WT (RCH-ACV 4853 vs 3212, SEM 10052 vs 7595, RPMI-8402 20392 vs 12133, CEM 10155 vs 6437). ChIP-Seq revealed general large gains of H3K36me2 in intergenic regions in NSD2 mutant cells. Importantly, genes upregulated with NSD2 mutation (e.g., NCAM1 and NEO1) lost H3K27me3 at promoters but gained H3K36me2 at promoters and whole gene bodies, accompanied with increased H3K27ac at enhancers. Conversely, a small subset of genes gained H3K27me3 and lost H3K36me2 in their promoters. Concentrated H3K36me2 in gene bodies diffused and broadened was less prominent and H3K27me3 accumulation became dominant. This for example was associated with repression of NR3C1 to drive GC resistance of NSD2 mutant cells. Genes upregulated in NSD2 mutant cells were enriched for binding sites for lymphoid transcriptional activators such as EBF1 and IRF2. The promoters of the downregulated genes had motifs for transcription factors poorly expressed in lymphoid cells and were enriched for binding sites for the BCL6 transcriptional repressor. Hi-C analysis revealed 430 topologically associated domains (TADs) with increased loop interactions while 136 TADs with decreased interactions were in NSD2 mutant cells compared to WT cells. Overall, 491 regions switched from compartment A to B and 444 regions switched from B to A in NSD2 mutant cells compared to WT cells. Compartment switching from inactive B to active A correlated with upregulated gene expression levels while the reverse was true for switching from A to B. Increased intra-TAD interactions were linked to upregulated genes while decreased intra-TAD interactions were linked to downregulated genes.Conclusions: The NSD2 mutation led to increased tumor burden, CNS infiltration and glucocorticoid resistance due to dysregulation of epigenetic patterns and 3D chromatin architecture, indicating mechanisms underlying the relapse of pediatric ALL and potential therapeutic targets in ALL with NSD2 mutation. DisclosuresLicht: Epizyme: Research Funding.

Predictive Biomarkers of Pathological Response to Neoadjuvant Radiochemotherapy for Locally Advanced Soft Tissue Sarcomas

<h3>Purpose/Objective(s)</h3> Soft tissue sarcomas (STS) is a large group of rare cancers which present high intratumoral heterogeneity. Thus, the assessment of response to the neoadjuvant treatment applied for locally advanced STS remains a challenge. We hypothesized that the pathological response (PR) could be predicted using biomarkers of the tumor microenvironment, hypoxia, and DNA damage. <h3>Materials/Methods</h3> We analyzed prospectively collected core biopsy tissue samples from patients who received preoperative 5 × 5 Gy with doxorubicin-ifosfamide for marginally resectable high-grade STS in a phase II clinical trial. We have chosen tumor-infiltrating macrophages (TAMs) and intratumoral microvascular density (IMVD) as biomarkers for the tumor microenvironment. Hypoxia-inducible factor 1-alpha (HIF1A) expression was selected as a biomarker of intratumoral hypoxia. Double-strand DNA breaks were evaluated by expression of the phosphorylated form of H2A histone family member X (gH2AFX). Immunohistochemical analysis (CD163, CD68, CD105, CD34, HIF1A, gH2AFX) was evaluated by experienced sarcoma pathologists blinded to sample identification with a semi-quantitative method. We scored TAMs by counting the number of positive-staining macrophages per mm2: 0-none, 1-low, and 2-high. IMVD were counted in five randomly selected fields at 200x magnification (∼6.9 mm2), and a total number of microvessels included scoring scale: 1 (1-25), 2 (26-50), 3 (51-100), and 5 (> 500). HIF1A and gH2AFX were assessed in H-score scale, including intensity: 0-none, 1-weak, 2-moderate, 3-strong, and percentage of stained cells in each category (range: 0-300). All markers were studied preoperatively, while HIF1A was additionally assessed in postoperative tissues to define hypoxic microenvironment shift after therapy. PR to the treatment was classified using the European Organization for Research and Treatment of Cancer-Soft Tissue and Bone Sarcoma Group recommendations; grades A, B, C indicated good PR, whereas D and E suggested poor PR. Spearman rank correlation was used to measure the degree of association between biomarkers and PR. <h3>Results</h3> Nineteen patients were eligible for the analysis. We identified a good treatment PR in four cases (grades A = 1, B = 2, C = 1, D = 11, E = 4). High tumor infiltration with TAMs and high IMVD did not correlate with PR. High initial expression of HIF1A correlated with poor PR, whereas high expression of gH2AFX correlated with better PR (Tab. 1). We also confirmed decreased HIF1A expression after therapy between biomarkers and PR. <h3>Conclusion</h3> HIF1A (hypoxia degree) and gH2AFX (DNA damage extent) are candidate biomarkers for PR's prediction after neoadjuvant treatment in STS. Further evaluation in prospective studies is warranted.

Myeloid Cell Infiltration Correlates With Prognosis in Cholangiocarcinoma and Varies Based on Tumor Location.

Cholangiocarcinoma (CC) is an uncommon malignancy with increasing incidence and dismal prognosis. We conducted a comprehensive analysis of the CC tumor immune microenvironment (TIME) based on tumor location to identify therapeutic targets. We hypothesized that the TIME of CC would vary by primary tumor location and that high tumor infiltration by CD8+ T cells and low infiltration by M2 macrophages would be associated with improved survival. A retrospective analysis was conducted of 99 CC tumor samples surgically resected between 2000 and 2014. Tissue microarrays were constructed from each tumor and stained by immunohistochemistry for 24 markers of immune cells, immune activation or inhibition, programmed cell death-ligand 1, and mesothelin. Most tumors were amply infiltrated with by CD4+, CD8+, and FoxP3+ T cells, as well as by myeloid cells. Mesothelin expression ≥1+ by immunohistochemistry was found in 68% of tumors. We identified higher densities of M1 macrophages in primary distal extrahepatic CC, as well as metastatic lesions. Mesothelin expression was also significantly higher in distal extrahepatic CC. There was no association with survival of infiltration by CD4+, CD8+, or FoxP3+ T cells, mesothelin expression, or programmed cell death-ligand 1 percentage expression, however, high CD14+ myeloid cells and high CD163+ M2 macrophages were associated with worse survival. In conclusion, the CC TIME is a heterogenous milieu highly infiltrated by innate and adaptive immune cells, which differs based on primary tumor location and between primary tumors and metastatic lesions. The correlation of intratumoral M2 macrophages and myeloid cells with a worse prognosis may suggest promising immunotherapeutic targets in CC.

Development and Validation of a Metabolic Gene-Based Prognostic Signature for Hepatocellular Carcinoma

BackgroundHepatocellular carcinoma (HCC) is a malignant tumor with great variation in prognosis among individuals. Changes in metabolism influence disease progression and clinical outcomes. The objective of this study was to determine the overall survival (OS) risk of HCC patients from a metabolic perspective.Patients and MethodsThe model was constructed using the least absolute shrinkage and selection operator (LASSO) COX regression based on The Cancer Genome Atlas (TCGA, n=342) dataset. The International Cancer Genome Consortium (ICGC, n=232), GSE14520 (n=242) datasets, and a clinical cohort (n=64) were then used to assess the prognostic value of the signature.ResultsA 10 metabolic gene-based signature was constructed and verified as a robust and independent prognostic classifier in public and real-world validation cohorts. Meanwhile, the signature enabled the identification of HCC molecular subtypes, yielding an AUC value of 0.678 [95% CI: 0.592–0.763]. Besides, the signature was associated with metabolic processes like glycolysis, supported by a clear correlation between the risk score and expression of rate-limiting enzymes. Furthermore, high-risk tumor was likely to have a high tumor infiltration status of immunosuppressive cells, as well as elevated expression of some immune checkpoint molecules. For final clinical translation, a nomogram integrating the signature and tumor stage was established, and showed improved predictive accuracy of 3- and 5-year OS and brought more net benefit to patients.ConclusionWe developed a prognostic signature based on 10 metabolic genes, which has proven to be an independent and reliable prognostic predictor for HCC and reflects the metabolic and immune characteristics of tumors.