Microenvironment Of Carcinoma Research Articles

Apparent diffusion coefficient and tissue stiffness are associated with different tumor microenvironment features of hepatocellular carcinoma.

To investigate associations between tissue diffusion, stiffness, and different tumor microenvironment features in resected hepatocellular carcinoma (HCC). Seventy-two patients were prospectively included for preoperative magnetic resonance (MR) diffusion-weighted imaging and MR elastography examination. The mean apparent diffusion coefficient (ADC) and stiffness value were measured on the central three slices of the tumor and peri-tumor area. Cell density, tumor-stroma ratio (TSR), lymphocyte-rich HCC (LR-HCC), and CD8 + T cell infiltration were estimated in resected tumors. The interobserver agreement of MRI measurements and subjective pathological evaluation was assessed. Variables influencing ADC and stiffness were screened with univariate analyses, and then identified with multivariable linear regression. The potential relationship between explored imaging biomarkers and histopathological features was assessed with linear regression after adjustment for other influencing factors. Seventy-two patients (male/female: 59/13, mean age: 56 ± 10.2 years) were included for analysis. Inter-reader agreement was good or excellent regarding MRI measurements and histopathological evaluation. No correlation between tumor ADC and tumor stiffness was found. Multivariable linear regression confirmed that cell density was the only factor associated with tumor ADC (Estimate = -0.03, p = 0.006), and tumor-stroma ratio was the only factor associated with tumor stiffness (Estimate = -0.18, p = 0.03). After adjustment for fibrosis stage (Estimate = 0.43, p < 0.001) and age (Estimate = 0.04, p < 0.001) in the multivariate linear regression, intra-tumoral CD8 + T cell infiltration remained a significant factor associated with peri-tumor stiffness (Estimate = 0.63, p = 0.02). Tumor ADC surpasses tumor stiffness as a biomarker of cellularity. Tumor stiffness is associated with tumor-stroma ratio and peri-tumor stiffness might be an imaging biomarker of intra-tumoral immune microenvironment. Tissue stiffness could potentially serve as an imaging biomarker of the intra-tumoral immune microenvironment of hepatocellular carcinoma and aid in patient selection for immunotherapy. Apparent diffusion coefficient reflects cellularity of hepatocellular carcinoma. Tumor stiffness reflects tumor-stroma ratio of hepatocellular carcinoma and is associated with tumor-infiltrating lymphocytes. Tumor and peri-tumor stiffness might serve as imaging biomarkers of intra-tumoral immune microenvironment.

Regulatory effect of Yinchenhao decoction on bile acid metabolism to improve the inflammatory microenvironment of hepatocellular carcinoma in mice.

Hepatocellular carcinoma (HCC) is a malignant tumor with extremely high mortality. The tumor microenvironment is the "soil" of its occurrence and development, and the inflammatory microenvironment is an important part of the "soil". Bile acid is closely related to the occurrence of HCC. Bile acid metabolism disorder is not only directly involved in the occurrence and development of HCC but also affects the inflammatory microenvironment of HCC. Yinchenhao decoction, a traditional Chinese medicine formula, can regulate bile acid metabolism and may affect the inflammatory microenvironment of HCC. To determine the effect of Yinchenhao decoction on bile acid metabolism in mice with HCC and to explore the possible mechanism by which Yinchenhao decoction improves the inflammatory microenvironment of HCC by regulating bile acid metabolism, we established mice model of orthotopic transplantation of hepatocellular carcinoma. These mice were treated with three doses of Yinchenhao decoction, then liver samples were collected and tested. Yinchenhao decoction can regulate the disorder of bile acid metabolism in liver cancer mice. Besides, it can improve inflammatory reactions, reduce hepatocyte degeneration and necrosis, and even reduce liver weight and the liver index. Taurochenodeoxycholic acid, hyodeoxycholic acid, and taurohyodeoxycholic acid are important molecules in the regulation of the liver inflammatory microenvironment, laying a foundation for the regulation of the liver tumor inflammatory microenvironment based on bile acids. Yinchenhao decoction may improve the inflammatory microenvironment of mice with HCC by ameliorating hepatic bile acid metabolism.

Abstract PO2-25-06: A hybrid breast cancer/mesenchymal stem cell population increases distant metastasis and chemoresistance of metaplastic breast carcinomas

Abstract Background: Metaplastic breast carcinoma is a heterogenous, highly aggressive and chemoresistant subtype of triple negative breast cancer (TNBC) with histological evidence of deregulated differentiation towards non-glandular components including spindle, squamous, and sarcomatoid. The role of the tumor microenvironment in the metastatic behavior and chemotherapy response of metaplastic carcinomas needs investigation to improve patient outcomes. Our lab has generated a model of spindle metaplastic breast carcinomas based on mammary epithelial cell-specific CCN6 knockout (MMTV-Cre;Ccn6fl/fl or CCN6KO). We have recently shown that a subset of TNBC cells engulf mesenchymal stem/stromal cells (MSC) generating a hybrid cell population with metastatic ability, which is detected in breast cancer tissue samples. In this study, we tested the hypothesis that hybrid cells may promote chemoresistant distant metastasis in spindle metaplastic breast carcinomas and that the tumor immune microenvironment may play a role in this function. Methods: Luc-GFP-CCN6KO cells were cultured with DsRED-MSCs for 7 days, yielding &amp;gt;90% of hybrid cells detected by flow cytometry. Hybrids or CCN6KO single cultures (1x10(5) cells) were injected intracardially in FVB/NJ syngeneic immune competent mice (n=20 mice per group). Four days after injection, each group was treated with Paclitaxel (PTX, 10 mg/kg twice a week, i.p.) or PBS control. The metastatic burden was evaluated by bioluminescence imaging twice a week. Mice were euthanized 23 days after heart injections, followed by necropsy and histopathological evaluation of the harvested organs. Results: All mice injected with single cultures of CCN6KO cells or hybrid cells formed distant metastasis. CCN6KO cells were highly invasive and spread to the lungs and lymph nodes in the chest,. We noted that 5 of 20 (25%) mice injected with hybrid cells showed metastasis in the liver (n=3 mice), pancreas (n=1), and abdominal lymph nodes (n=1). PTX treatment significantly reduced metastatic burden in mice injected with CCN6KO single cultures compared to vehicle (p=0.035) but had no effect on the metastatic burden of hybrid cells. Histologically, while the metastasis from CCN6KO cells and hybrids showed similar pathological features, consisting of spindle cancer cells with high grade nuclei and &amp;gt;10 mitoses/10 high power fields, hybrid-derived tumors had abundant infiltration by immune cells, mainly neutrophils, compared to single culture tumors. Conclusion: Our data show that hybrid cancer cell/MSC derived from CCN6KO spindle metaplastic carcinomas have higher ability to disseminate to distant organs, especially in the abdomen, compared to cancer cells. Our data show that hybrid cell-derived metastases have increased immune cell infiltration. We provide evidence that hybrid cells enhance Paclitaxel resistance in a mouse model of metaplastic breast carcinoma. Ongoing studies are aimed at elucidating the role of hybrids in the immune microenvironment of metaplastic breast carcinoma and clinical significance. Citation Format: Ahmad Eido, Maria Gonzalez, Celina Kleer. A hybrid breast cancer/mesenchymal stem cell population increases distant metastasis and chemoresistance of metaplastic breast carcinomas [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-25-06.

Multifaceted roles of lymphatic and blood endothelial cells in the tumor microenvironment of hepatocellular carcinoma: A comprehensive review.

The tumor microenvironment is a complex network of cells, extracellular matrix, and signaling molecules that plays a critical role in tumor progression and metastasis. Lymphatic and blood vessels are major routes for solid tumor metastasis and essential parts of tumor drainage conduits. However, recent studies have shown that lymphatic endothelial cells (LECs) and blood endothelial cells (BECs) also play multifaceted roles in the tumor microenvironment beyond their structural functions, particularly in hepatocellular carcinoma (HCC). This comprehensive review summarizes the diverse roles played by LECs and BECs in HCC, including their involvement in angiogenesis, immune modulation, lymphangiogenesis, and metastasis. By providing a detailed account of the complex interplay between LECs, BECs, and tumor cells, this review aims to shed light on future research directions regarding the immune regulatory function of LECs and potential therapeutic targets for HCC.

Spatial profiling of ovarian carcinoma and tumor microenvironment evolution under neoadjuvant chemotherapy.

Immune tumor microenvironment (iTME) determines ovarian cancer development. This study investigates changes in HLA-I expression, CD8+/Foxp3 ratio, CD8+ cells and coregulators density at diagnosis and upon neoadjuvant chemotherapy (NACT), correlating changes with clinical outcomes. Multiplexed immune profiling and cell clustering analysis was performed on paired matched OC samples to characterize the iTME at diagnosis and under NACT from patients enrolled in the CHIVA trial (NCT01583322). Several immune cells (IC) subsets and immune coregulators were quantified pre-/post-NACT. At diagnosis, patients with higher CD8+ T cells and HLA-1+ enriched tumors were associated with -better outcome. The CD8+/Foxp3+ ratio increased significantly post-NACT in favor of increased immune surveillance and the influx of CD8+ T cells predicted better outcomes. Clustering analysis stratified pre-NACT tumors into 4 subsets: high Binf, enriched in B clusters; high Tinf, low Tinf, according to their CD8+ density; and desert clusters. At baseline, these clusters were not correlated with patient outcomes. Under NACT, tumors segregated into 3 clusters: high BinfTinf, low Tinf and desert. The high BinfTinf, more diverse in IC composition encompassing T, B and NK cell, correlated with improved survival. PD-L1 was rarely expressed, while TIM-3, LAG- and IDO-1 were more prevalent. Several iTMEs exist during tumor evolution and NACT impact on iTME is heterogeneous. Clustering analysis of patients, unravels several IC subsets within OC and can guide future personalized approaches. Targeting different checkpoints such as TIM-3, LAG-3 and IDO-1, more prevalent than PD-L1, could more effectively harness anti-tumor immunity in this anti-PD-L1 resistant malignancy.

The role of alpha-fetoprotein in the tumor microenvironment of hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a prevalent malignant cancer worldwide, characterized by high morbidity and mortality rates. Alpha-fetoprotein (AFP) is a glycoprotein synthesized by the liver and yolk sac during fetal development. However, the serum levels of AFP exhibit a significant correlation with the onset and progression of HCC in adults. Extensive research has demonstrated that the tumor microenvironment (TME) plays a crucial role in the malignant transformation of HCC, and AFP is a key factor in the TME, promoting HCC development. The objective of this review was to analyze the existing knowledge regarding the role of AFP in the TME. Specifically, this review focused on the effect of AFP on various cells in the TME, tumor immune evasion, and clinical application of AFP in the diagnosis and treatment of HCC. These findings offer valuable insights into the clinical treatment of HCC.

Role of innate lymphoid cells in oral squamous cell carcinoma microenvironment

Oral squamous cell carcinoma (OSCC) is the most common oral malignancy. It has a high incidence, strong invasion ability, easy metastasis, poor curative effect, and poor prognosis. Innate lymphoid cells (ILCs) are an important part of immune cells located in the mucosal barrier, which play an important role in the occurrence, development and outcome of tumors. ILCs are the key cells for decoding the regulatory mechanism of tumor microenvironment and the signatures for tumor progression. This paper reviewed the latest progress on ILCs, summarized the possible characteristics and functions of ILCs in the microenvironment of OSCC, and explored the relationship between ILCs and the occurrence, development and immunotherapy of OSCC.

Clinicopathological characteristics and immune microenvironment of breast squamous cell carcinoma

Objective: To investigate the clinicopathological characteristics of breast squamous cell carcinoma and to analyze the relationship between its immune microenvironment tumor infiltrating lymphocytes (TILs) and prognosis. Methods: Forty-four cases of primary squamous cell carcinoma of the breast diagnosed and treated in the First Affiliated Hospital of Air Force Medical University, Xi'an, China from January 2006 to July 2022 were selected. Their clinicopathological characteristics were analyzed. The cell composition of TILs was evaluated using immunohistochemistry (Mainly markers of B lymphocytes, T lymphocytes and plasma cells). The relationship between TILs and prognosis was also analyzed. Results: The 44 patients of breast squamous cell carcinoma were all female and all were invasive carcinoma. Eight cases (8/44, 18.2%) were squamous cell carcinoma, while 36 cases (36/44, 81.8%) were mixed squamous cell carcinoma. The mixed components included non-specific carcinoma and spindle cell metaplastic carcinoma (17 cases each). One case contained ductal carcinoma in situ of the breast and 1 case contained tubular carcinoma. The proportion of squamous cell carcinoma was 10% to 90%. The cases with pure squamous cell carcinoma often had a large cystic cavity, which was lined by atypical squamous epithelium, while infiltrating squamous cell carcinoma nests were seen in the breast tissue around the cystic cavity. Immunohistochemical staining showed that p63 and CK5/6 were expressed in the squamous cell carcinoma component, but ER, PR and HER2 were not, except for one case of HER2 1+. The positive rates of TRPS1 and PDL-1 were 76% and less than 1%, respectively. Fifteen cases were in the high TILs group (TILs≥30%) and 29 cases were in the low TILs group (TILs<30%). Twenty-three patients were followed up for 5 to 118 months. Among them, 12 died within 3 years and 9 were alive at the end of the follow up. There was no significant difference in TNM stage, TILs and prognosis between simple squamous cell carcinoma and mixed squamous cell carcinoma. Conclusions: Breast squamous cell carcinoma can be divided into simple squamous cell carcinoma and mixed squamous cell carcinoma. There are differences in gross findings and histology between the simple and mixed squamous cell carcinoma of the breast. Sufficient samples should be taken to avoid missing the diagnosis of a minor squamous component. The prognosis of patients with high TILs is significantly better than that of patients with low TILs. The expression rate of TRPS1 in primary squamous cell carcinoma of breast is high and helpful to the differential diagnosis from metastatic squamous cell carcinoma.

Metabolome Profiling of Malignant Ascites Identifies Candidate Metabolic Biomarkers of Hepatocellular Carcinoma.

Malignant ascites is one of the severe complications of hepatocellular carcinoma, which can be regarded as a unique tumor microenvironment of hepatocellular carcinoma. The identification of novel biomarkers in malignant ascites could be crucial to differentiate patients with hepatocellular carcinoma and cirrhotic ascites. The study aimed to distinguish the metabolomics of malignant ascites in patients with hepatocellular carcinoma from that of non-malignant ascites (cirrhotic ascites). Liquid chromatography-mass spectrometry was performed to analyze the differentially distributed biomarkers in patients with malignant ascites and hepatocellular carcinoma (n = 39), as well as in patients with cirrhotic ascites, which were taken as controls (n = 36). A total of 20 differential metabolites associated with malignant ascites were identified, of which 8 metabolites were upregulated and 12 metabolites were downregulated (ratio < 0.5 or > 1.5, respectively). Moreover, pathway and enrichment analyses revealed nitrogen metabolism, urea cycle, phenylalanine, and tyrosine metabolism to be implicated in the formation of malignant ascites in patients with hepatocellular carcinoma. Our results suggest that the key factors associated with pathways, such as arachidonic acid, phenylalanine, and glutamic acid pathways, are potential ascitic fluidbased biomarkers for differentiating hepatocellular carcinoma with cirrhosis ascites; the results also provide a clinical pathophysiological interpretation of biomarkers and metabolic pathways relevant to disease status.

Difference between Keratinized- and Non-Keratinized-Originating Epithelium in the Process of Immune Escape of Oral Squamous Cell Carcinoma.

Immune checkpoint inhibitors (ICIs), including anti-programmed cell death 1 ligand 1 (PD-L1) antibodies, are significantly changing treatment strategies for human malignant diseases, including oral cancer. Cancer cells usually escape from the immune system and acquire proliferative capacity and invasive/metastatic potential. We have focused on the two immune checkpoints, PD-1/PD-L1 and CD47/SIRPα, in the tumor microenvironment of oral squamous cell carcinoma (OSCC), performed a retrospective analysis of the expression of seven immune-related factors (PD-L1, PD-1, CD4, CD8, CD47, CD56 and CD11c), and examined their correlation with clinicopathological status. As a result, there were no significant findings relating to seven immune-related factors and several clinicopathological statuses. However, the immune checkpoint-related factors (PD-1, PD-L1, CD47) were highly expressed in non-keratinized epithelium-originated tumors when compared to those in keratinized epithelium-originated tumors. It is of interest that immunoediting via immune checkpoint-related factors was facilitated in non-keratinized sites. Several researchers reported that the keratinization of oral mucosal epithelia affected the immune response, but our present finding is the first study to show a difference in tumor immunity in the originating epithelium of OSCC, keratinized or non-keratinized. Tumor immunity, an immune escape status of OSCC, might be different in the originating epithelium, keratinized or non-keratinized.

The Immune Microenvironment and Immune Therapy Response Mechanism of Renal Clear Cell Carcinoma

The purpose of this article is to study the immune microenvironment characteristics of renal clear cell tumor and the application effect of immunotherapy in this tumor. In order to achieve this goal, this article adopts systematic experimental methods and analytical means. Firstly, the distribution of tumor infiltrating immune cells and the expression of key immune molecules were described in detail by collecting renal clear cell tumor samples and using flow cytometry, immunohistochemistry and other technical means. Subsequently, in vitro and in vivo experiments of immunotherapy were designed and implemented to evaluate the anti-tumor effects of different immunotherapy strategies. The experimental results show that the immune microenvironment of renal clear cell tumor presents unique characteristics, including the infiltration mode of immune cells and the expression profile of immune molecules. Both in vitro and in vivo immunotherapy experiments show that some immunotherapy strategies can effectively inhibit the growth of renal clear cell tumor and prolong the survival time of animal models. Based on the above findings, it can be concluded that the immune microenvironment of renal clear cell tumor plays a key role in tumor progression and immunotherapy response. A deep understanding of the characteristics and regulation mechanism of immune microenvironment is helpful to develop more effective immunotherapy strategies.

The Role of Natural Killer Cells in the Tumor Immune Microenvironment of EBV-Associated Nasopharyngeal Carcinoma.

Endemic nasopharyngeal carcinoma (NPC) is closely associated with the Epstein-Barr virus (EBV), which contributes to tumor development and influences the tumor immune microenvironment (TIME) in NPC. Natural killer (NK) cells, as part of the innate immune system, play a crucial role in responding to viral infections and malignant cell transformations. Notably, NK cells possess a unique ability to target tumor cells independent of major histocompatibility complex class I (MHC I) expression. This means that MHC I-deficient tumor cells, which can escape from effective T cell attack, are susceptible to NK-cell-mediated killing. The activation of NK cells is determined by the signals generated through inhibitory and activating receptors expressed on their surface. Understanding the role of NK cells in the complex TIME of EBV+ NPC is of utmost importance. In this review, we provide a comprehensive summary of the current understanding of NK cells in NPC, focusing on their subpopulations, interactions, and cytotoxicity within the TIME. Moreover, we discuss the potential translational therapeutic applications of NK cells in NPC. This review aims to enhance our knowledge of the role of NK cells in NPC and provide valuable insights for future investigations.

Analysis of the effect of CCR7 on the microenvironment of mouse oral squamous cell carcinoma by single-cell RNA sequencing technology

BackgroundStudies have shown that CCR7, an important inflammatory factor, can promote the proliferation and metastasis of oral squamous cell carcinoma (OSCC), but its role in the tumor microenvironment (TME) remains unclear. This paper explores the role of CCR7 in the TME of OSCC.MethodsIn this work, we constructed CCR7 gene knockout mice and OSCC mouse models. Single-cell RNA sequencing (scRNA-seq) and bioinformatics were used to analyze the differences in the OSCC microenvironment between three CCR7 gene knockout mice (KO) and three wild-type mice (WT). Immunohistochemistry, immunofluorescence staining, and flow cytometry were used to analyze the expression of key genes in significantly different cell types between the KO and WT groups. An in vitro experiment was used to verify the effect of CCR7 on M2 macrophage polarization.ResultsIn the mouse OSCC models, the tumor growth rate in the KO group was significantly lower than that in the WT group. Eight main cell types (including tumor cells, fibroblasts, macrophages, granulocytes, T cells, endothelial cells, monocytes, and B cells) were identified by Seurat analysis. The scRNA-seq results showed that the proportion of tumor cells was lower, but the proportion of inflammatory cells was significantly higher in the KO group than in the WT group. CellPhoneDB analysis results indicated a strong interaction relationship between tumor cells and macrophages, T cells, fibroblasts, and endothelial cells. Functional enrichment results indicated that the expression level of the Dusp1 gene in the KO group was generally higher than that in the WT group in various cell types. Macrophage subclustering results indicated that the proportion of M2 macrophages in the KO group was lower than that in the WT group. In vitro experimental results showed that CCR7 can promote M2 macrophage polarization, thus promoting the proliferation, invasion and migration of OSCC cells.ConclusionsCCR7 gene knockout can significantly inhibit the growth of mouse oral squamous cell carcinoma by promoting the polarization of M2 macrophages.

Abstract 1526: The distinct tumor microenvironment of advanced hepatocellular carcinoma with high PVR or high PD-L1 expression

Abstract Background: The combination of anti-PD-L1 and anti-VEGF has been the standard-of-care for advanced hepatocellular carcinoma (HCC), while additionally targeting TIGIT is under active investigation. We aimed to explore the expression and clinical significance of PVR (CD155), the ligand of TIGIT, within the tumor microenvironment (TME) of advanced HCC. Methods: All HCC tumor specimens were obtained at the advanced stage of HCC. Immunohistochemistry (IHC) was employed to evaluate membranous staining of PVR and PD-L1 of tumor specimens, and semiquantitative scores with IHC 0, 1, 2, or 3 were given if &amp;lt; 1%, ≥1% but &amp;lt; 5%, ≥5% but &amp;lt; 10%, or ≥10% of tumor cells (TCs) and tumor-infiltrating immune cells (ICs) were PVR or PD-L1 positive. Selected tumor specimens underwent immune gene expression profiling using the nCounter Analysis System (NanoString Technologies, Inc.) with the PanCancer Immune Profiling Panel. Results: The study enrolled 67 advanced HCC patients, with median age of 59.2 years (male:female = 57:10). Forty-eight (71.6%) of the patients were hepatitis B virus (HBV) surface antigen positive, and 23 (34.3%) had received sorafenib before the study. Thirteen (19.4%) and 18 (26.9%) tumor tissues showed positive PVR expressions (IHC scores ≥1) in TCs and ICs, respectively; Seventeen (25.4%) and 36 (53.7%) tumor tissues showed positive PD-L1 expressions in TCs and ICs, respectively. The expressions of PVR in TCs or ICs showed no association with clinical factors, such as sex, age, HBV infection, sorafenib treatment, or overall survival. Interestingly, in both TCs and ICs, the intensities of PVR and PD-L1 expression were inversely correlated for those with at least IHC scores ≥1 in either PVR or PD-L1 (TCs, n = 26, r = -0.6966, p &amp;lt; 0.0001; ICs, n = 46, r = -0.4548, p = 0.0015). Immune profiling of the selected tumor specimens showed that those with high PVR but low PD-L1 expressions had significantly lower CD8 T cells scores, lower cytotoxic cells scores, and lower CD8/Treg ratio than those with high PD-L1 but low PVR expressions. Conclusions: There was an inverse correlation observed between expressions of PVR and PD-L1 in the advanced HCC tissues. The TME of those with high PVR expression was distinct from those with high PD-L1 expression. These findings may have important clinical implications for developing combination immunotherapy in advanced HCC. (This work is supported by grants from the Ministry of Science and Technology, Taiwan, MOST 110-2314-B-002-204-MY3). Citation Format: Li-Chun Lu, Yi-Hsuan Lee, Tsung-hao Liu, Yu-Yun Shao, Ann-Lii Cheng, Chih-Hung Hsu. The distinct tumor microenvironment of advanced hepatocellular carcinoma with high PVR or high PD-L1 expression [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 1526.

Abstract 5490: Spatial profiling of inflamed tumor microenvironment of clear cell renal cell carcinoma

Abstract Clear cell renal cell carcinoma (ccRCC) presents a distinctive tumor microenvironment (TME) characterized by extensive vascularization and immune infiltration. This unique TME makes ccRCC an attractive target for anti-angiogenesis and immune checkpoint blockade (ICB). To better understand the complexity of ccRCC and the associated cell types and states involved in disease progression, we conducted high-throughput single-cell immunofluorescence imaging on tissue sections from 437 localized tumors that were surgically resected. These samples included regions from the tumor center, tumor edge, and adjacent benign areas (TMA cores, n=1859). Our primary focus was on tumors with elevated immune cell enrichment (CD45high), as these tumors are known to be aggressive and may respond well to immunotherapy. Our study reveals the intricate interactions between tumor, vascular, stromal, and immune cells within ccRCC. We find that CD45high tumors, upon losing epithelial marker expression, acquire tumor cell PD-L1 and mesenchymal markers such as Fibroblast activation protein (FAP). This shift is indicative of the epithelial-mesenchymal transition (EMT) process. These CD45high and EMThigh tumors are enriched with changes in TME, including elevated FAP+ cancer-associated fibroblasts (CAFs) and subsets of immune suppressive T cells and macrophages. We report that ccRCC patients with high tumor PD-L1 expression or abundant FAP+ CAFs are associated with earlier metastasis and, in sunitinib-treated patients, shorter progression-free survival. This study illuminates the intricate connection between immune cell infiltration, stromal biology, and EMT in ccRCC, offering a deeper understanding of the disease's complex biology and potentially guiding future therapeutic approaches and strategies. Citation Format: Teijo Pellinen, Lassi Luomala, Kalle Mattila, Jenni Säilä, Annabrita Hemmes, Katja Valimaki, Oscar Bruck, Lassi Paavolainen, Harry Nisen, Petrus Järvinen, Olli Kallioniemi, Paula Vainio, Panu Jaakkola, Tuomas Mirtti. Spatial profiling of inflamed tumor microenvironment of clear cell renal cell carcinoma [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 5490.

Abstract 7398: Unveiling the tumor microenvironment of hepatocellular carcinoma using AI trained by spatial transcriptomics: A preliminary study to predict response to immunotherapy

Abstract Background. Immune checkpoint inhibitors (ICIs), particularly targeting the PD-1 pathway, are promising in treating hepatocellular carcinoma (HCC). However, their variable effectiveness among individuals calls for a better understanding of the tumor microenvironment (TME) and reliable predictive biomarkers. Here, we employ spatial transcriptomics (ST) to develop a deep-learning model that aims to investigate the TME in HCC using Hematoxylin and eosin (H&amp;E) staining images. Our focus is on identifying cell types within the TME that are linked to the response to ICI in a cohort of patients treated with nivolumab. Methods. Our study leveraged 21 Visium ST datasets from HCC to develop a model aimed at inferring the cellular composition of TME from H&amp;E images that matched with ST data. The comprehensive TME cell types enrichment score, encompassing Tumor Endothelial Cells (TECs), Tumor-Associated Macrophages (TAMs), B cells, T cells, and Cancer-Associated Fibroblasts (CAFs) in each spot, was calculated by the CellDART algorithm, a method that maps cell type by integrating with a reference scRNA-seq data. The model was trained in a patch-wise manner, utilizing a pre-trained ResNetRS50 as the backbone model. For the internal validation, Spearman correlation coefficients were evaluated for predicted cell types using H&amp;E, and the trained model was correlated with cell type enrichment scores estimated by ST datasets of 4 samples independent of the training set. The model was applied to H&amp;E images of 16 patients with HCC who underwent nivolumab treatment. The model predicted the 5 cell types enrichment score in the tumor and tumor-adjacent normal liver tissues. Results. The internal validation set results demonstrate robust Spearman correlations between our model predictions and actual cellular compositions in the TME. Specifically, we observe strong correlations for T cells (rho = 0.66), TAMs (rho=0.46), CAFs (rho=0.32), B cells (rho=0.30), and TECs (rho=0.24). When we applied the model to the H&amp;E images of the cohort of patients who underwent nivolumab, immunotherapy non-responders showed a significantly higher predicted enrichment score of CAFs in tumor-adjacent regions (Mann-Whitney test, p&amp;lt;.01). Upon stratifying patients based on stromal CAF prediction, those with low stromal CAF levels exhibited better overall survival (Log-rank test, p&amp;lt;.05). Conclusions. We present a deep learning model to analyze TME in HCC solely on H&amp;E images trained by ST data. Our findings showed a potential relationship between CAFs in tumor-adjacent regions and non-responders to nivolumab treatment in HCC. These insights underscore the potential to predict nivolumab treatment responders using H&amp;E images combined with the deep learning model. This approach could provide a significant advancement in personalized treatment strategies for HCC patients. Citation Format: Dongjoo Lee, Haenara Shin, Seungho Cook, Daeseung Lee, Hongyoon Choi, Won-Mook Choi, Changhoon Yoo, Kwon Joong Na. Unveiling the tumor microenvironment of hepatocellular carcinoma using AI trained by spatial transcriptomics: A preliminary study to predict response to immunotherapy [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 7398.

High expression of UBE2S promotes progression of hepatocellular carcinoma by increasing cancer cell stemness

To investigate the expression of the ubiquitination enzyme UBE2S in different cell types in hepatocellular carcinoma (HCC) microenvironment and its impact on proliferation and stemness of HCC cells. TCGA and CPTAC database were used to analyze the transcriptional and promoter methylation levels and protein expressions of UBE2S in HCC. Specific expression patterns of UBE2S, intercellular communication and key transcription factors in different cell types were analyzed based on single-cell sequencing data from TISCH website. We further examined UBE2S expressions in clinical samples of HCC tissues, HCC cells and T cells using immunohistochemistry and immunofluorescence staining. We also tested the effects of UBE2S knockdown on stemness of HCC-LM3 and HepG2 cells using clone formation experiments and sphere formation assay. Analysis based on TCGA database suggested significant overexpression of UBE2S in both paired and non-paired tumor tissues (P < 0.001), and its transcriptional level increased with tumor grades. The methylation level of UBE2S promoter was significantly decreased in HCC (P < 0.001), and its transcription level increased obviously in HCC with TP53 mutation (P < 0.001). Analysis of CPTAC database also demonstrated overexpression of UBE2S protein in HCC tissues (P < 0.001). Three prognostic models suggested that HCC patients with high UBE2S expression had poorer prognosis (P < 0.001). Single-cell sequencing data analysis revealed high expressions of UBE2S in T cells and high intensities of interaction between endothelial cells, epithelial cells and fibroblasts in HCC microenvironment. Immunohistochemistry and immunofluorescence staining demonstrated high UBE2S expressions in clinical samples of HCC tissues, HCC cells and T cells. In HCC-LM3 and HepG2 cells, UBE2S knockdown significantly inhibited cell clone formation and tumor sphere formation (P < 0.05). UBE2S is highly expressed in T cells in HCC microenvironment in close correlation with a poor prognosis. High UBE2S expression promotes the stemness of HCC cells.

HOXD3 promotes the migration and angiogenesis of hepatocellular carcinoma via modifying hepatocellular carcinoma cells exosome-delivered CCR6 and regulating chromatin conformation of CCL20

Angiogenesis plays an essential role in the microenvironment of hepatocellular carcinoma (HCC). HOXD3 is involved in the metastasis and invasion of HCC cells; Whereas the underlying molecular mechanisms in the microenvironment of HCC remain unknown. Wound healing, transwell invasion, tube formation and spheroid sprouting assays were carried out to identify the effects of HCC-HOXD3-exosomes and genes on the migration of HCC cells. ChIP–PCR was applied to test the binding region of HOXD3 on CCR6, Med15, and CREBBP promoter. Exosome isolation and mRNA-seq were applied to examine the morphological characteristics of exosomes and the contained mRNA in exosomes. Co-IP and Immunofluorescence assays were used to demonstrate the role of CREBBP in the chromatin conformation of CCL20. The nude mice were used to identify the function of genes in regulating migration of HCC in vivo. In this study, integrated cellular and bioinformatic analyses revealed that HOXD3 targeted the promoter region of CCR6 and induced its transcription. CCR6 was delivered by exosomes to endothelial cells and promoted tumour migration. Overexpression of CCR6 promoted metastasis, invasion in HCCs and angiogenesis in endothelial cells (ECs), whereas its downregulation suppressed these functions. The role of HOXD3 in the metastasis and invasion of HCC cells was reversed after the suppression of CCR6. Furthermore, CCL20 was demonstrated as the ligand of CCR6, and its high expression was found in HCC tissues and cells, which was clinically associated with the poor prognosis of HCC. Mechanistically, HOXD3 targets the promoter regions of CREBBP and Med15, which affect CCL20 chromatin conformation by regulating histone acetylation and expression of Pol II to enhance the migration of HCCs. This study demonstrated the function of the HOXD3–CREBBP/Med15–CCL20–CCR6 axis in regulating invasion and migration in HCC, thus providing new therapeutic targets for HCC.

Arenobufagin modulation of PCSK9-mediated cholesterol metabolism induces tumor-associated macrophages polarisation to inhibit hepatocellular carcinoma progression

BackgroundThe tumor microenvironment (TME) of hepatocellular carcinoma is heterogeneous enough to be prone to drug resistance and multidrug resistance during treatment, and reprogramming of cholesterol metabolism in TME mediates tumor-associated macrophages (TAMs) polarization, which has an impact on the regulation of malignant tumor progression. Arenobufagin (ARBU) was extracted and isolated from toad venom (purity ≥98 %), which is the main active ingredient of the traditional Chinese medicine Chan'su with good anti-tumor effects. PurposeTo investigate the regulatory effect of ARBU on lipid metabolism in tumor microenvironment, interfere with macrophage polarization, and determine its mechanism of action on liver cancer progression. MethodsIn this study, the inhibitory effect of ARBU on the proliferation of Hepa1–6 in C57 mice and the safety of administration were evaluated by establishing a transplanted tumor model of Hepa1–6 hepatocellular carcinoma mice and using 5-FU as a positive control drug. In addition, we constructed a co-culture system of Hepa1–6 cells and primary mouse macrophages to study the effects of ARBU on the polarization phenotypic transformation of macrophages and the proliferation and migration of hepatoma cells. The influence of ARBU on the metabolism of lipids in the hepatocellular carcinoma mouse model was investigated by combining it with lipidomics technology. The influence of ARBU on the PCSK9/LDL-R signaling pathway and macrophage polarization, which regulate cholesterol metabolism, was tested by using qRT-PCR, gene editing, IF, and WB. ConclusionARBU significantly inhibited the proliferation of Hepa1–6 in vivo and in vitro, regulated cholesterol metabolism, and promoted the M1-type polarization of macrophages in the tumor microenvironment. ARBU inhibits cholesterol synthesis in the TME through the PCSK9/LDL-R signaling pathway, thereby blocking macrophage M2 polarization, promoting apoptosis of the tumor cells, and inhibiting their proliferation and migration.

Characterization of the distinct immune microenvironments between hepatocellular carcinoma and intrahepatic cholangiocarcinoma

As two major types of primary liver cancers, the tumor immune microenvironment (TIME) of hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC) have been well studied separately. However, a systemic assessment of the similarities and differences between the TIME of HCC and ICC is still lacking. In this study, we pictured a landscape of combined TIME of HCC and ICC by sequencing and integrating 41 single-cell RNA-seq samples from four different tissue types of both malignancies. We found that T cells in HCC tumors generally exhibit higher levels of immunosuppression and exhaustion than those in ICC tumors. Myeloid cells in HCC and ICC tumors also exhibit distinct phenotypes and may serve as a key factor driving the differences between their TIMEs. Besides, we identified a cluster of EGR1+ macrophages specifically enriched in HCC tumors. Together, our study provides new insights into cellular composition, states and interactions in the TIMEs of HCC and ICC, which could pave the way for the development of future therapeutic targets for liver cancers.