Human Cancer Microenvironment Research Articles

Pan-Cancer Analysis of GALNT6 with Potential Implications for Prognosis and Tumor Microenvironment in Human Cancer Based on Bioinformatics and qPCR Verification.

We explored the expression and prognostic value of GALNT6 and the tumor microenvironment of pan-cancer in humans. In this study, we explored the expression pattern of GALNT6 pan-cancer across multiple databases. The prognostic value of GALNT6 was evaluated using the Kaplan-Meier method. The types and numbers of GALNT6 gene alterations were exhibited using the cBio Cancer Genomics Portal. The correlations between GALNT6 expression and immune infiltration in cancers were analyzed using the database Tumor Immune Estimation Resource 2. We also used the Kyoto Encyclopedia of Genes and Genomes pathway and Gene Ontology analysis to investigate the molecular mechanisms of the GALNT6 gene in tumorigenesis. The expression of GALNT6 was also further verified by qPCR in lung adenocarcinoma tissues. In general, compared with normal tissue, tumor tissue had a higher expression level of GALNT6. GALNT6 showed a protective effect in colon carcinoma and other cancers; however, a high expression level of GALNT6 was detrimental to survival in bladder cancer and in pheochromocytoma and paraganglioma. Mutation, amplification, and deep deletion were the three main types of GALNT6 mutations in tumors. There was a significant positive correlation between GALNT6 expression and immune infiltration of CD8+ T-cells in skin cutaneous melanoma metastasis, based on most of the algorithms used. Moreover, protein processing- and glycoprotein metabolic-associated functions were involved in the functional mechanisms of GALNT6. This first pan-cancer study offers a relatively comprehensive understanding of the oncogenic roles of GALNT6 across different cancer types.

Comprehensive analysis of the effects of the cuprotosis-associated gene SLC31A1 on patient prognosis and tumor microenvironment in human cancer.

Solute carrier family 31 (copper transporter), member 1 (SLC31A1) is a key factor in maintaining intracellular copper concentration and an important factor affecting cancer energy metabolism. Therefore, exploring the potential biological function and value of SLC31A1 could provide a new direction for the targeted therapy of tumors. This study assessed gene expression levels, survival, clinicopathology, gene mutations, methylation levels, the tumor mutational burden (TMB), microsatellite instability (MSI), and the immune cell infiltration of SLC31A1 in pan-cancer using the Tumor Immune Estimation Resource 2.0 (TIMER2.0), Gene Expression Profiling Interactive Analysis (GEPIA), University of Alabama at Birmingham CANcer (UALCAN) data analysis portal, and cBioPortal databases. To further understand the potential biological mechanisms of SLC31A1 in different cancers, single-cell level sequencing and a Gene Ontology/Kyoto Encyclopedia of Genes and Genomes (GO/KEGG) enrichment analysis of SLC31A1 were also performed. Finally, real-time quantitative polymerase chain reaction (RT-qPCR) and western blotting (WB) were used to validate the expression of SLC31A1 in cancers, such as gastric cancer. SLC31A1 was expressed in most cancer tissues. In kidney renal clear cell carcinoma (KIRC), the high expression of SLC31A1 was associated with good overall survival (OS), while in adrenocortical carcinoma (ACC), breast invasive carcinoma (BRCA), lower grade glioma (LGG), mesothelioma (MESO), and skin cutaneous melanoma (SKCM), the low expression of SLC31A1 was associated with good OS. The highest frequency of SLC31A1 amplification was observed in ACC. In addition, missense mutations accounted for a major portion of the mutation types. The truncation mutation S105Y may be a putative cancer driver. SLC31A1 affected methylation levels in cancer and was associated with the TMB, MSI, and the level of infiltration of various immune cells. Additionally, the single-cell sequencing results showed that SLC31A1 was associated with multiple biological functions in cancer. Finally, the SLC31A1 enrichment analysis revealed that the SLC31A1-related genes were mainly enriched in the mitochondrial matrix and envelope vesicles. The RT-qPCR and WB results were consistent with the predicted results. SLC31A1 may be a potential target related to cancer energy metabolism and may have prognostic value.

Abstract B030: Spatial coupling of microbes and immune cells shapes the tumor microenvironment in human cancers

Abstract Microbes play a crucial role in the tumor microenvironment, yet the factors governing their presence within tumors remain poorly understood. In this study, we employed advanced in situ spatial-profiling technologies to investigate the relationship between microbial and immune cell heterogeneity in human lung and pancreas cancers. We observed a spatial coupling between microbes and immune cells, which was also replicated in mouse models of pancreatic cancer. Within the tumor, distinct niches characterized by T cell abundance or scarcity exhibited varied microbial diversity and compositions associated with immunologically active and quiescent phenotypes. Interestingly, gut microbiome are similar between mice bearing T cell- enriched or T cell-poor pancreas tumors. Depletion of intra-tumoral bacteria resulted in reduced tumor growth specifically in T cell-poor tumors and altered the phenotype and presence of myeloid and B cells in T cell-enriched tumors, without affecting T cell infiltration. Conversely, depletion of T cells disrupted the immunological state of tumors and led to a decrease in intra-tumoral bacteria. Our findings highlight a tight interplay between microbes and T cells in the tumor microenvironment, where spatially defined immune-microbial communities differentially influence tumor biology. Citation Format: Yan Li, Renee B. Chang, Meredith L. Stone, Yuqing Xue, Heather Coho, Kelly Markowitz, Dhruv Patel, Veronica M. Herrera, Joey H. Li, Devora Delman, Liti Zhang, Shaanti Choi-Bose, Michael Giannone, Jae W. Lee, Gregory Beatty. Spatial coupling of microbes and immune cells shapes the tumor microenvironment in human cancers [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr B030.

Patient-derived scaffolds representing breast cancer microenvironments influence chemotherapy responses in adapted cancer cells consistent with clinical features

BackgroundThe tumor microenvironment clearly influences cancer progressing properties but less is known about how individual cancer microenvironments potentially moderate cancer treatment effects. By cultivating and treating cancer cell lines in patient-derived scaffolds (PDS), the impact of specific characteristics of individual cancer microenvironments can be incorporated in human-like growth modelling and cancer drug treatment testing.MethodsPDSs from 78 biobanked primary breast cancer samples with known patient outcomes, were prepared and repopulated with donor breast cancer cell lines, followed by treatment with 5-fluorouracil or doxorubicin after cellular adaption to the various microenvironments. Cancer cell responses to the treatments were monitored by RNA-analyses, highlighting changes in gene sets representative for crucial tumor biological processes such as proliferation, cancer stem cell features, differentiation and epithelial-to-mesenchymal transition.ResultsThe chemotherapy treatments induced distinct gene expression patterns in adapted cancer cells with clusters of similar treatment responses depending on the patient-derived cancer microenvironment used as growth substrate. The doxorubicin treatment displayed a favorable gene signature among surviving cancer cells with low proliferation (MKI67) and pluripotency features (NANOG, POU5F1), in comparison to 5-fluorouracil showing low proliferation but increased pluripotency. Specific gene changes monitored post-treatment were also significantly correlated with clinical data, including histological grade (NANOG), lymph node metastasis (SLUG) and disease-free patient survival (CD44).ConclusionsThis laboratory-based treatment study using patient-derived scaffolds repopulated with cancer cell lines, clearly illustrates that the human cancer microenvironment influences chemotherapy responses. The differences in treatment responses defined by scaffold-cultures have potential prognostic and treatment predictive values.

CYFIP2 serves as a prognostic biomarker and correlates with tumor immune microenvironment in human cancers

BackgroundThe mechanisms whereby CYFIP2 acts in tumor development and drives immune infiltration have been poorly explored. Thus, this study aimed to identifying the role of CYFIP2 in tumors and immune response.MethodsIn this study, we first explored expression patterns, diagnostic role and prognostic value of CYFIP2 in cancers, particularly in lung adenocarcinoma (LUAD). Then, we performed functional enrichment, genetic alterations, DNA methylation analysis, and immune cell infiltration analysis of CYFIP2 to uncover its potential mechanisms involved in immune microenvironment.ResultsWe found that CYFIP2 significantly differentially expressed in different tumors including LUAD compared with normal tissues. Furthermore, CYFIP2 was found to be significantly correlated with clinical parameters in LUAD. According to the diagnostic and survival analysis, CYFIP2 may be employed as a potential diagnostic and prognostic biomarker. Moreover, genetic alterations revealed that mutation of CYFIP2 was the main types of alterations in different cancers. DNA methylation analysis indicated that CYFIP2 mRNA expression correlated with hypomethylation. Afterwards, functional enrichment analysis uncovered that CYFIP2 was involved in tumor-associated and immune-related pathways. Immune infiltration analysis indicated that CYFIP2 was significantly correlated with immune cells infiltration. In particular, CYFIP2 was strongly linked with immune microenvironment scores. Additionally, CYFIP2 exhibited a significant relationship with immune regulators and immune-related genes including chemokines, chemokines receptors, and MHC genes.ConclusionOur results suggested that CYFIP2 may serve as a prognostic cancer biomarker for determining prognosis and might be a promising therapeutic strategy for tumor immunotherapy.

Abstract 1408: Increased infiltrating class-switched memory B cell in breast cancer tumors were associated with favorable prognostic outcome

Abstract Introduction: Tumor infiltrating lymphocytes are well known as an important component in the microenvironment in human cancers, including breast cancer tumors. Not only tumor infiltrating T cells, but B cells have been recognized as a new hallmark of cancer immunity. However, the roles of each B cell subset remain unclear. We investigated the breast cancer biology from the point of view of tumor infiltrating B cells. Methods: Genomic for primary breast tumors and clinical data were obtained from The Cancer Genome Atlas in Pan-Cancer Atlas publications. Fraction for 64 immune and stroma cell subsets, such as memory- and class-switched memory B cells and CD4+ memory T cell were quantified by xCell method, a performs cell type enrichment analysis from bulk tumor gene expression data. Individual tumors were dichotomized according to each cell fraction levels by median cut-off value. B receptor repertoire (BCR) recognizing specific receptor molecules on several cancer cells, were quantified from complementarity determining region (CDR) 3 sequences in the variable chains in immunoglobulins by TRUST method. Gene set enrichment analysis were demonstrated using Hallmark gene-sets. Results: CD4+ memory T cell was the dominant lymphocyte subsets (40.7%) followed by Th1 cells (22.8%) and class-switched memory B cell (3.4%). Patients with higher B cell infiltrating tumor were associated with improved disease-free survival (HR = 0.56, p = 0.01). Moreover, class-switched memory B cell was found to be the most significant prognostic factor (disease-free survival; HR = 0.23, p = 0.095, overall survival; HR = 0.33, p = 0.046). On the other hand, pro-, memory-B cells were not significant for disease outcome. Gene sets related to cell proliferation like mitotic spindle and G2M checkpoint were rather down regulated in tumors with high class-switched memory B cell infiltration compared to those with low (enrichment score = -1.63 and -1.71, p = 0.04 and 0.03, respectively). The number of unique CDR3 in breast cancer tumor has positive correlation with BCR index (Spearman r = 0.63, P <0.01), and higher class-switched memory B cell infiltrated tumors were associated with more unique CDR3s, also BCR index (P <0.01 and P <0.01, respectively). Conclusion: We found that increased infiltrating class-switched memory B cell in breast cancer associates with down-regulated cancer cell proliferation with favorable outcome. The heightened diversity of the B cell receptor caused by genome rearrangement in complementarity determining region also associated with class-switched memory B cell infiltration into breast cancer tumors. Citation Format: Mariko Asaoka, Rongrong Wu, Takashi Ishikawa. Increased infiltrating class-switched memory B cell in breast cancer tumors were associated with favorable prognostic outcome [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 1408.

Pan-cancer analysis of trophinin-associated protein with potential implications in clinical significance, prognosis, and tumor microenvironment in human cancers

Trophinin-associated protein (TROAP), a cytoplasmic protein, is essential for microtubule cytoskeleton assembly. Mounting evidence demonstrates the vital role of TROAP in regulating the proliferation and migration of cells, but it is unclear how it contributes to cancer progression. The online portals of GEPIA2, Cancer Cell Line Encyclopedia, UALCAN, Human Protein Atlas, and PrognoScan were used to analyze TROAP expression in various tumors and further evaluate its correlation with prognosis. With Western blot and quantitative real-time PCR analysis, we validated TROAP expression levels in hepatocellular carcinoma (HCC) and colorectal cancer (CRC). Ten pairs of HCC and CRC tissues were selected for immunohistochemistry to determine TROAP expression levels in tumors and adjacent tissues, respectively. TROAP knockdown in CRC and HCC cells to verify its role in malignant phenotypes. The genomic and post-transcriptional alterations of TROAP in tumors were determined using the cBioPortal and SangerBox databases. Also, TISIDB was used to investigate the relationship between TROAP expression and tumor microenvironment(TME) among different cancer types. Moreover, a correlation was found between the expression of TROAP and drug sensitivity using GSCALite and CellMiner databases. TROAP expression was significantly upregulated in most cancer types, which is consistent with our validated experimental results in HCC and CRC cells, and immunohistochemistry results. And a poor prognosis was linked to TROAP aberrant expression. Our findings indicated that malignant phenotypes and tumorigenesis induced by TROAP could be due to an activation of the PI3K/Akt/GSK-3β signaling pathway. Furthermore, we found a correlation between TROAP expression and genomic and post-transcriptional alterations in various tumors, including tumor mutation burden, and microsatellite instability. Next, we demonstrated that TROAP expression was associated with the infiltration of immune cells, such as neutrophils and macrophages, and correlated with immunomodulation-related genes in the TME. Additionally, the potential role of TROAP expression in predicting the sensitivity of drugs, including melphalan and chlorambucil, was demonstrated. Collectively, these findings indicated a significant correlation between TROAP expression and malignant phenotype, functional mechanism, survival possibility, TME, therapeutic potential, and prediction of drug sensitivity in various cancers. Hence, TROAP is a promising biomarker and therapeutic target for predicting cancer outcomes.

High tumor hexokinase-2 expression promotes a pro-tumorigenic immune microenvironment by modulating CD8+/regulatory T-cell infiltration

BackgroundRelationship between cancer cell glycolysis and the landscape of tumor immune microenvironment in human cancers was investigated.MethodsForty-one fresh lung adenocarcinoma (ADC) tissues were analyzed using flow cytometry for comprehensive immunoprofiling. Formalin-fixed tissues were immunostained for hexokinase-2 (HK2) to assess cancer cell glycolysis. For validation, formalin-fixed tissues from 375 lung ADC, 118 lung squamous cell carcinoma (SqCC), 338 colon ADC, and 78 lung cancer patients treated with anti-PD-1/PD-L1 immunotherapy were immunostained for HK2, CD8, and FOXP3.ResultsBased on immunoprofiling of lung ADC, HK2 tumor expression was associated with the composition of lymphoid cells rather than myeloid cells. High HK2 tumor expression was associated with immunosuppressive/pro-tumorigenic features, especially decreased ratio of CD8 + T-cells to Tregs (rho = −0.415, P = 0.012). This correlation was also confirmed in four different cohorts including lung ADC and SqCC, colon ADC, and the immunotherapy cohort (rho = −0.175~-0.335, all P < 0.05). A low CD8 + T-cell to Treg ratio was associated with poor progression-free survival and overall survival in lung SqCC patients, and a shorter overall survival in the immunotherapy cohort (all, P < 0.05).ConclusionAn increase in HK2 expression may contribute to shaping the immunosuppressive/pro-tumorigenic tumor microenvironment by modulating the CD8 + T-cell to Treg ratio. Targeting tumor HK2 expression might be a potential strategy for enhancing anti-tumor immunity.

Integrative pan-cancer landscape of MMS22L and its potential role in hepatocellular carcinoma.

Methyl methanesulfonate-sensitivity protein 22-like (MMS22L) is crucial in protecting genome integrity during DNA replication by preventing DNA damage and maintaining efficient homologous recombination. However, the role of MMS22L in human cancers remains unclear. Here, we reported the landscape of MMS22L using multi-omics data and identified the relationship between the MMS22L status and pan-cancer prognosis. In addition, the correlation of MMS22L mRNA expression levels with tumor mutational burden, microsatellite instability, homologous recombination deficiency, and loss of heterozygosity in pan-cancer was also described in this study. Furthermore, this study was the first to characterize the relationship between mRNA expression of MMS22L and immune cell infiltration in the tumor microenvironment in human cancer. Concurrently, this study explored the crucial role of MMS22L in different immunotherapy cohorts through current immunotherapy experiments. Eventually, we investigated the role of MMS22L in hepatocellular carcinoma (HCC). The results demonstrated that MMS22L is widely expressed in multiple HCC cell lines, and our results emphasized that MMS22L was involved in HCC progression and affects the prognosis of patients with HCC through multiple independent validation cohorts. Collectively, our findings reveal the essential role of MMS22L as a tumor-regulating gene in human cancers while further emphasizing its feasibility as a novel molecular marker in HCC. These findings provide an essential reference for the study of MMS22L in tumors.

Visualizing the Interactions Shaping the Imaging of the Microenvironment in Human Cancers.

The Visium Spatial Gene Expression Solution (Visium 10×) allows for the mRNA analysis using high throughput sequencing and maps a transcriptional expression pattern in tissue sections using high-resolution microscope imaging in ex-vivo human and mice samples. The workflow surveys spatial global gene expression in tissue sections, exploiting the whole transcriptome profiling and defining the set of transcripts via targeted gene panels. An automated cell type annotation allows a comparison with control tissue samples. This technique delineates cancerous or diseased tissue boundaries and details gene expression gradients in the tissue surrounding the tumor or pathologic nests. Remarkably, the Visium 10× allows for whole transcriptome and targeted analysis without the loss of spatial information. This approach provides gene expression data within the context of tissue architecture, tissue microenvironments, and cell groups. It can be used in association with therapy, anti-angiogenic therapy, and immunotherapy to improve treatment response.

Cancer-Associated Fibroblasts: Tumorigenicity and Targeting for Cancer Therapy.

Simple SummaryCancer-associated fibroblasts (CAFs) are found in the tumor microenvironment and exhibit several protumorigenic functions. Preclinical studies suggest that CAFs can be reduced, eliminated, or reprogrammed; however, clinical translation has not yet occurred. A better understanding of these cells and their functions will undoubtedly improve cancer treatments. In this review, we summarize current research, highlight major challenges, and discuss future opportunities for improving our knowledge of CAF biology and targeting.Cancer-associated fibroblasts (CAFs) are a heterogenous group of activated fibroblasts and a major component of the tumor stroma. CAFs may be derived from fibroblasts, epithelial cells, endothelial cells, cancer stem cells, adipocytes, pericytes, or stellate cells. These complex origins may underlie their functional diversity, which includes pro-tumorigenic roles in extracellular matrix remodeling, the suppression of anti-tumor immunity, and resistance to cancer therapy. Several methods for targeting CAFs to inhibit tumor progression and enhance anti-tumor immunity have recently been reported. While preclinical studies have shown promise, to date they have been unsuccessful in human clinical trials against melanoma, breast cancer, pancreas cancer, and colorectal cancers. This review summarizes recent and major advances in CAF-targeting therapies, including DNA-based vaccines, anti-CAF CAR-T cells, and modifying and reprogramming CAF functions. The challenges in developing effective anti-CAF treatment are highlighted, which include CAF heterogeneity and plasticity, the lack of specific target markers for CAFs, the limitations in animal models recapitulating the human cancer microenvironment, and the undesirable off-target and systemic side effects. Overcoming these challenges and expanding our understanding of the basic biology of CAFs is necessary for making progress towards safe and effective therapeutic strategies against cancers in human patients.

A novel 3D co-culture platform for integrating tissue interfaces for tumor growth, migration and therapeutic sensitivity: “PP-3D-S”

Metastatic cancers can be highly heterogeneous, show large patient variability and are typically hard to treat due to chemoresistance. Personalized therapies are therefore needed to suppress tumor growth and enhance patient's quality of life. Identifying appropriate patient-specific therapies remains a challenge though, due mainly to non-physiological in vitro culture systems. Therefore, more complex and physiological in vitro human cancer microenvironment tools could drastically aid in development of new therapies. We developed a plasma-modified, electro-spun 3D scaffold (PP-3D-S) that can mimic the human cancer microenvironment for customized-cancer therapeutic screening. The PP-3D-S was characterized for optimal plasma-modifying treatment and scaffolds morphology including fiber diameter and pore size. PP-3D-S was then seeded with human fibroblasts to mimic a stromal tissue layer; cell adhesion on plasma-modified poly (lactic acid), PLA, electrospun mats vastly exceeded that on untreated controls. The cell-seeded scaffolds were then overlaid with alginate/gelatin-based hydrogel embedded with MDA-MB231 human breast cancer cells, representing a tumor-tissue interface. Among three different plasma treatments, we found that NH3 plasma promoted the most tumor cell migration to the scaffold surfaces after 7 days of culture. For all treated and non-treated mats, we observed a significant difference in tumor cell migration between small-sized and either medium- or large-sized scaffolds. In addition, we found that the PP-3D-S was highly comparable to the standard Matrigel® migration assays in two different sets of doxorubicin screening experiments, where 75% reduction in migration was achieved with 0.5 μM doxorubicin for both systems. Taken together, our data indicate that PP-3D-S is an effective, low-cost, and easy-to-use alternate 3D tumor migration model which may be suitable as a physiological drug screening tool for personalized medicine against metastatic cancers.

Conceptual Analogies Between Multi-Scale Feeding and Feedback Cycles in Supermassive Black Hole and Cancer Environments.

Adopting three physically-motivated scales (“micro” – “meso” – “macro”, which refer to mpc – kpc – Mpc, respectively) is paramount for achieving a unified theory of multiphase active galactic nuclei feeding and feedback, and it represents a keystone for astrophysical simulations and observations in the upcoming years. In order to promote this multi-scale idea, we have decided to adopt an interdisciplinary approach, exploring the possible conceptual similarities between supermassive black hole feeding and feedback cycles and the dynamics occurring in human cancer microenvironment.

Tertiary Lymphoid Structures in Colorectal Cancer Liver Metastases: Association With Immunological and Clinical Parameters and Chemotherapy Response.

The presence of TLS (tertiary lymphoid structures) is detectable in the microenvironment of human cancers and linked to better patient outcomes. The role of TLS in colorectal cancer liver metastases (CRCLM) is unclear. Medical records of patients with CRCLM were reviewed (n=33) and corresponding tissue samples (n=21) were obtained. Whole slide imaging analyses on immunohistochemical staining of immune cell infiltrates and TLS were correlated to clinical outcomes (including chemotherapy response) and other parameters. Neither the size (p=0.6) nor the quantity (p=0.47) of TLS was associated with the clinical course. When considering spatial differences, TLS in the invasive margin (IM) were associated with progression-free survival (p=0.03), while TLS in the LM (liver metastasis) were not. Also, TLS in the IM were associated with the presence of CD3+ T cells, which itself was prognostically favorable (p<0.001). TLS in the IM are associated with good prognosis in CRCLM, but not chemotherapy response.

Microsatellite instability status differentially associates with intratumoral immune microenvironment in human cancers.

Based on clinical outcomes in colorectal cancer, high microsatellite instability (MSI-H) has recently been approved by the Food and Drug Administration (FDA) as a genetic test to select patients for immunotherapy targeting PD-1 and/or CTLA-4 without limitation to cancer type. However, it is unclear whether the MSI-H would broadly alter the tumor microenvironment to confer the therapeutic response of different cancer types to immunotherapy. To fill in this gap, we performed an in silico analysis of tumor immunity among different MSI statuses in five cancer types. We found that consistent with clinical responses to immunotherapy, MSI-H and non-MSI-H samples from colorectal cancer (COAD-READ) exhibited distinct infiltration levels and immune phenotypes. Surprisingly, the immunological difference between MSI-H and non-MSI-H samples was diminished in stomach adenocarcinoma and esophageal carcinoma (STAD-ESCA) and completely disappeared in uterine corpus endometrial carcinoma (UCEC). Regardless of cancer types, the abundance of tumor-infiltrating immune cells, rather than MSI status, strongly associated with the clinical outcome. Since preexisting antitumor immune response in the tumor (hot cancer) is accepted as a prerequisite to the therapeutic response to anti-PD-1/CTLA-4 immunotherapy, our data demonstrate that the impact of MSI varied on immune contexture will lead to the further evaluation of predictive immunotherapy responsiveness based on the universal biomarker of MSI status.

Galectin-9 promotes a suppressive microenvironment in human cancer by enhancing STING degradation

Galectin-9 (Gal-9) is known to enhance the expansion of myeloid-derived suppressor cells (MDSCs) in murine models. Its contribution to the expansion of MDSCs in human malignancies remain to be investigated. We here report that Gal-9 expression in nasopharyngeal carcinoma (NPC) cells enhances the generation of MDSCs (CD33+CD11b+HLA-DR−) from CD33+ bystander cells. The underlying mechanisms involve both the intracellular and secreted Gal-9. Inside carcinoma cells, Gal-9 up-regulates the expression of a variety of pro-inflammatory cytokines which are critical for MDSC differentiation, including IL-1β and IL-6. This effect is mediated by accelerated STING protein degradation resulting from direct interaction of the Gal-9 carbohydrate recognition domain 1 with the STING C-terminus and subsequent enhancement of the E3 ubiquitin ligase TRIM29-mediated K48-linked ubiquitination of STING. Moreover, we showed that extracellular Gal-9 secreted by carcinoma cells can enter the myeloid cells and trigger the same signaling cascade. Consistently, high concentrations of tumor and plasma Gal-9 are associated with shortened survival of NPC patients. Our findings unearth that Gal-9 induces myeloid lineage-mediated immunosuppression in tumor microenvironments by suppressing STING signaling.

Abstract IA18: Metabolic impact on cancer immunity

Abstract We have studied the crosstalk among immune cell subsets, including myeloid cells, and tumor (stem) cells in the tumor microenvironment, and its impact on tumor progression, tumor immunity, and therapy. Our research efforts demonstrate that the tumor microenvironment comprises immune cells that have been reprogrammed by active tumor-mediated processes to defeat tumor immunity and promote tumor progression in a highly effective manner. These studies, including the first demonstration of PD-L1 expression, regulation, and blockade in the human cancer microenvironment, have helped define the nature of immune responses in the cancer microenvironment, form the concept of immunosuppressive networks in the cancer microenvironment, and provide significant insights into designing current immune therapies to treat cancer patients. In this talk, I focus on cancer metabolic impact on regulatory T cells and effector T cells. (a) Regulatory T cells and oxidative stress in the cancer microenvironment: Using ovarian cancer as an example, we found that tumor Treg cells undergo apoptosis and such apoptotic Treg cells abolish spontaneous and PD-L1 blockade-mediated antitumor T-cell immunity. Biochemical and functional analyses identify that adenosine, but not typical suppressive factors such as PD-L1, CTLA4, TGF-β, IL-35, and IL-10, contributes to apoptotic Treg cell-mediated immunosuppression. Mechanistically, apoptotic Treg cells release and convert a large amount of ATP to adenosine via CD39 and CD73, and mediate immunosuppression via the adenosine and A2A pathway. Treg cell apoptosis is attributed to their weak NRF2-associated antioxidant system and high vulnerability to free oxygen species in the tumor microenvironment. Thus, the data support a model wherein tumor Treg cells sustain and amplify their suppressor capacity by inadvertent death via oxidative stress. The work highlights the oxidative pathway as a metabolic checkpoint controlling Treg cell behavior and affecting cancer checkpoint therapeutic efficacy. (b) Effector T cells and glutamate-cystine metabolism in the cancer microenvironment: In patients with ovarian cancer and melanoma, and in multiple tumor-bearing mouse models, we find that immunotherapy-activated CD8+ T cells sensitize tumor cell ferroptosis. Mechanistically, IFNg released from CD8+ T cells downregulates expression of SLC3A2 and SLC7A11, two subunits of glutamate-cystine antiporter system xc-, restrains tumor cell cystine uptake, and as a consequence, promotes tumor cell lipid peroxidation and ferroptosis. In preclinical models, depletion of cyst(e)ine by cyst(e)inase in combination with checkpoint blockade synergistically enhances T cell-mediated antitumor immunity and induces tumor cell ferroptosis. Expression of glutamate-cystine antiporter system xc- is negatively associated with CD8+ T-cell signature, IFNg expression, and cancer patient outcome. Transcriptome analyses before and during nivolumab therapy reveal that clinical benefits correlate with reduced expression of SLC3A2 and increased IFNg and CD8. Thus, T cell-promoted tumor ferroptosis is a novel antitumor mechanism. Targeting tumor ferroptosis pathway constitutes a therapeutic approach in combination with checkpoint blockade. Citation Format: Weiping Zou. Metabolic impact on cancer immunity [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr IA18.

Targeting DNA Repair to Drive Immune Responses: It's Time to Reconsider the Strategy for Clinical Translation.

PARP inhibition induces robust local and systemic antitumor immune responses and curative responses when combined with immune checkpoint blockade in many preclinical studies. However, the combination has not markedly improved antitumor effect compared with individual agents in clinical trials to date. We propose that the data from these trials indicate a lack of synergistic interaction of PARP inhibition and immune checkpoint blockade, with implications for reexamining our current strategies for clinical translation. As current mouse models do not recapitulate the genomic heterogeneity or tumor microenvironment of human cancers, better models are urgently needed. Tumor-extrinsic factors modulate immune checkpoint blockade response and they may be better assessed in early-phase clinical trials with frequent tissue and blood sampling. Further work is also needed to uncover the dose and schedule dependency of DNA repair modulation on the immune system. In homologous recombination repair-deficient tumors, randomized trials should be prioritized to address whether the benefit is superior to that of PARP inhibitor monotherapy. In tumors that are not homologous recombination repair deficient, research biopsies should be integrated to early-phase clinical trials to discover biomarkers that can predict clinical benefit. These considerations are relevant to the variety of adjunctive therapeutics being combined with immune checkpoint blockade to improve probability, duration, and potency of antitumor activity.

Faithful preclinical mouse models for better translation to bedside in the field of immuno-oncology.

The success of immunotherapy using immune checkpoint inhibitors has changed the practice of cancer treatment tremendously. However, there are still many clinical challenges, such as drug resistance, predictive biomarker development, exploration of combination therapies, and prediction of immune-related adverse events in preclinical settings. To overcome these problems, it is essential to establish faithful preclinical mouse models that recapitulate the clinical features, molecular genetics, biological heterogeneity, and immune microenvironment of human cancers. Here we review the advantages and disadvantages of current preclinical mouse models, including syngeneic murine tumor cell lines, autochthonous tumor models, cancer cell line-derived xenografts, patient-derived-xenografts, and various kinds of immunologically humanized mice. We discuss how these models should be characterized and applied in preclinical settings, and how we should prepare preclinical studies for successful translation from bench to bedside.

Establishment and Analysis of a 3D Co-Culture Spheroid Model of Pancreatic Adenocarcinoma for Application in Drug Discovery.

The high attrition rate of oncology drug candidates can be in part explained by the disconnect between the standard preclinical models (e.g., 2D culture, xenograft tumors) commonly employed for drug discovery and the complex multicellular microenvironment of human cancers. As such, significant focus has recently shifted to the establishment of preclinical models that more closely recapitulate human tumors, such as patient-derived xenografts, 3D spheroids, humanized mice, and mixed-culture models. For these models to be suited to drug discovery, they should optimally exhibit reproducibility, high-throughput, and robust and simple assay readouts. In this article, we describe a protocol for the generation of an in vitro 3D co-culture spheroid model that recapitulates the interaction of tumor cells with stromal fibroblasts in pancreatic adenocarcinoma. We additionally describe protocols relevant to the analysis of these spheroids in high-throughput drug discovery campaigns such as the assessment of spheroid proliferation, immunofluorescence and immunohistochemistry staining of spheroids, live-cell and confocal imaging and analysis of cell surface markers.