Features Of Cancer-associated Fibroblasts Research Articles

Development of a Cancer-associated Fibroblast Signature for Evaluating Immunotherapy Response and Prognosis of Hepatocellular Carcinoma.

Alcohol abuse, non-alcoholic fatty liver disease (NAFLD), and hepatitis B and C are the main pathogenic factors of hepatocellular carcinoma (HCC). Though the current understanding of risk factors for HCC has been improved, patients with this type of cancer are normally diagnosed at advanced stages, posing significant challenges to effective treatment. This study analyzed the HCC datasets from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) database (GSE14520 and GSE116174). Stromal and immune cell infiltration in the tumor microenvironment (TME) was quantified by the ESTIMATE algorithm. To identify gene modules associated with cancer-associated fibroblasts (CAFs), weighted gene co-expression network analysis (WGCNA) was performed to develop gene co-expression networks. A CAF prognosis score (CAFPS) model was established based on the prognostic CAF genes screened by univariate and multivariate Cox regression analyses. To determine the role of the genes in the vital module in HCC, we conducted Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. Finally, the relationship between CAFPS and drug sensitivity was analyzed using Genomic Data for Cancer Drug Sensitivity (GDSC). In this study, we found significant differences in immune scores, stromal scores, CAFs scores, and CD4/8 T-cell scores between normal samples and samples with different TNM staging. In particular, the proportion of CAFs was higher than all other cells in normal samples. Gene modules related to CAFs were identified by developing a gene co-expression network using WGCNA analysis. The lightyellow and greenyellow modules showed the highest correlation with CAF scores. Univariate COX analysis identified 12 genes related to HCC prognosis from a total of 191 genes in the two modules. The Kaplan-Meier (KM) survival analysis revealed that a high expression of these genes was associated with a lower survival chance. Based on the 12 genes obtained by univariate COX analysis, multivariate COX analysis was performed to construct a risk score model for the characteristics of CAFs (CAFPS). The KM survival curves of patients in the high CAFPS and low CAFPS groups showed that patients in the low CAFPS group had better survival. CAFs played a crucial role in the pathogenesis and treatment response of HCC. Targeting the CAFs milieu may provide therapeutic benefits, highlighting the importance of CAFS in developing a personalized treatment for HCC patients. Further studies are required to verify the current findings and explore their implications in clinical settings.

Characterisation of colorectal cancer by hierarchical clustering analyses for five stroma-related markers.

Evidence for the tumour-supporting capacities of the tumour stroma has accumulated rapidly in colorectal cancer (CRC). Tumour stroma is composed of heterogeneous cells and components including cancer-associated fibroblasts (CAFs), small vessels, immune cells, and extracellular matrix proteins. The present study examined the characteristics of CAFs and collagen, major components of cancer stroma, by immunohistochemistry and Sirius red staining. The expression status of five independent CAF-related or stromal markers, decorin (DCN), fibroblast activation protein (FAP), podoplanin (PDPN), alpha-smooth muscle actin (ACTA2), and collagen, and their association with clinicopathological features and clinical outcomes were analysed. Patients with DCN-high tumours had a significantly worse 5-year survival rate (57.3% versus 79.0%; p = 0.044). Furthermore, hierarchical clustering analyses for these five markers identified three groups that showed specific characteristics: a solid group (cancer cell-rich, DCNLowPDPNLow); a PDPN-dominant group (DCNMidPDPNHigh); and a DCN-dominant group (DCNHighPDPNLow), with a significant association with patient survival (p = 0.0085). Cox proportional hazards model identified the PDPN-dominant group (hazard ratio = 0.50, 95% CI = 0.26-0.96, p = 0.037) as a potential favourable factor compared with the DCN-dominant group. Of note, DCN-dominant tumours showed the most advanced pT stage and contained the lowest number of CD8+ and FOXP3+ immune cells. This study has revealed that immunohistochemistry and special staining of five stromal factors with hierarchical clustering analyses could be used for the prognostication of patients with CRC. Cancer stroma-targeting therapies may be candidate treatments for patients with CRC.

Stable and oscillatory hypoxia differentially regulate invasibility of breast cancer associated fibroblasts

As local regions in the tumor outstrip their oxygen supply, hypoxia can develop, affecting not only the cancer cells, but also other cells in the microenvironment, including cancer associated fibroblasts (CAFs). Hypoxia is also not necessarily stable over time, and can fluctuate or oscillate. Hypoxia Inducible Factor-1 is the master regulator of cellular response to hypoxia, and can also exhibit oscillations in its activity. To understand how stable, and fluctuating hypoxia influence breast CAFs, we measured changes in gene expression in CAFs in normoxia, hypoxia, and oscillatory hypoxia, as well as measured change in their capacity to resist, or assist breast cancer invasion. We show that hypoxia has a profound effect on breast CAFs causing activation of key pathways associated with fibroblast activation, but reduce myofibroblast activation and traction force generation. We also found that oscillatory hypoxia, while expectedly resulted in a “sub-hypoxic” response in gene expression, it resulted in specific activation of pathways associated with actin polymerization and actomyosin maturation. Using traction force microscopy, and a nanopatterned stromal invasion assay, we show that oscillatory hypoxia increases contractile force generation vs stable hypoxia, and increases heterogeneity in force generation response, while also additively enhancing invasibility of CAFs to MDA-MB-231 invasion. Our data show that stable and unstable hypoxia can regulate many mechnobiological characteristics of CAFs, and can contribute to transformation of CAFs to assist cancer dissemination and onset of metastasis.

Abstract 5397: Characteristics of cancer associated fibroblasts isolated from refractory colorectal cancer using RNA sequence

Abstract Primary tumor location of colorectal cancers (CRCs) is emerging as an important prognostic factor owing to distinct biological features. In fact, the patients with right-side CRCs (R-CRCs), in which primary tumors were resected in our department and followed by systemic chemotherapy, have a poorer prognosis in 2-year overall survival and progression-free survival than those with left-side CRCs (L-CRCs). Furthermore, cancer-associated fibroblasts (CAFs) promote tumor malignancy, but the precise transcriptional mechanisms regulating the acquisition of the CAF phenotype are not well understood. Here, we isolated the CAFs and normal counterparts from 10 CRCs which were performed radical resection, including 5 L-CRCs and 5 R-CRCs, and analyzed transcriptomic profile of CAFs by RNA-sequencing. Gene Set Enrichment Analysis (GSEA) was performed and inflammatory signatures, such as "HALLMARK IL2 STAT5 SIGNALING"(NOM p-value<0.001, FDR q-value=0.146), "HALLMARK IL6 JAK STAT3 SIGNALING"(NOM p-value=0.014, FDR q-value=0.162), "HALLMARK INTERFERON GAMMA RESPONSE"(NOM p-value=0.032, FDR q-value=0.1726), were enriched in the CAFs isolated from R-CRCs (R-CAFs). In addition to sidedness of CRCs, based on gene expression profiles from bulk tumors, CRCs were classified into four consensus molecular subtypes (CMS1-4). Among them, The fibrotic CMS4 subtype portends poor relapse-free survival. We identified 4 CMS4-CRCs, which have the characteristics of stromal activation and the worst prognosis among other CRCs. GSEA showed that the signature of "HALLMARK TNFA_SIGNALING_VIA_NFKB" (NOM p-value=0.023 FDR q-value=0.207), "HALLMARK GLYCOLYSIS" (NOM p-value=0.036 FDR q-value=0.239) were upregulated in the CAFs isolated from CMS4-CRCs. These results indicated that CAFs isolated from refractory CRCs have unique phenotypes and the elucidation of these mechanisms might lead to a promising treatment for refractory CRCs. Citation Format: Hiroaki Kasashima, Yasuhiro Fukui, Ken Yonemitsu, Kisyu Kitayama, Yuichiro Miki, Mami Yoshii, Tatsunari Fukuoka, Tatsuro Tamura, Masatsune Shibutani, Takahiro Toyokawa, Shigeru Ree, Masakazu Yashiro, Kiyoshi Maeda. Characteristics of cancer associated fibroblasts isolated from refractory colorectal cancer using RNA sequence [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 5397.

BRCA1 mutation promotes sprouting angiogenesis in inflammatory cancer-associated fibroblast of triple-negative breast cancer

Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype with inferior outcomes owing to its low treatment response and high invasiveness. Based on abundant cancer-associated fibroblasts (CAFs) and frequent mutation of breast cancer-associated 1 (BRCA1) in TNBC, the characteristics of CAFs in TNBC patients with BRCA1 mutation compared to wild-type were investigated using single-cell analysis. Intriguingly, we observed that characteristics of inflammatory CAFs (iCAFs) were enriched in patients with BRCA1 mutation compared to the wild-type. iCAFs in patients with BRCA1 mutation exhibited outgoing signals to endothelial cells (ECs) clusters, including chemokine (C-X-C motif) ligand (CXCL) and vascular endothelial growth factor (VEGF). During CXCL signaling, the atypical chemokine receptor 1 (ACKR1) mainly interacts with CXCL family members in tumor endothelial cells (TECs). ACKR1-high TECs also showed high expression levels of angiogenesis-related genes, such as ANGPT2, MMP1, and SELE, which might lead to EC migration. Furthermore, iCAFs showed VEGF signals for FLT1 and KDR in TECs, which showed high co-expression with tip cell marker genes, including ZEB1 and MAFF, involved in sprouting angiogenesis. Moreover, BRCA1 mutation patients with relatively abundant iCAFs and tip cell gene expression exhibited a limited response to neoadjuvant chemotherapy, including cisplatin and bevacizumab. Importantly, our study observed the intricate link between iCAFs-mediated angiogenesis and chemoresistance in TNBC with BRCA1 mutation.

Characterization of cancer-associated fibroblasts (CAFs) and development of a CAF-based risk model for triple-negative breast cancer

Triple-negative breast Cancer (TNBC) is a highly malignant cancer with unclear pathogenesis. Within the tumor microenvironment (TME), cancer-associated fibroblasts (CAFs) vitally influence tumor onset and progression. Thus, this research aimed to identify distinct subgroups of CAF using single-cell and TNBC-related information from the GEO and TCGA databases, respectively. The primary aim was to establish a novel predictive model based on the CAF features and their clinical relevance. Moreover, the CAFs were analyzed for their immune characteristics, response to immunotherapy, and sensitivity to different drugs. The developed predictive model demonstrated significant effectiveness in determining the prognosis of patients with TNBC, TME, and the immune landscape of the tumor. Of note, the expression of GPR34 was significantly higher in TNBC tissues compared to that in other breast cancer (non-TNBC) tissues, indicating that GPR34 plays a crucial role in the onset and progression of TNBC. In summary, this research has yielded a novel predictive model for TNBC that holds promise for the accurate prediction of prognosis and response to immunotherapy in patients with TNBC.

Integrating single-cell and bulk RNA sequencing to predict prognosis and immunotherapy response in prostate cancer

Prostate cancer (PCa) stands as a prominent contributor to morbidity and mortality among males on a global scale. Cancer-associated fibroblasts (CAFs) are considered to be closely connected to tumour growth, invasion, and metastasis. We explored the role and characteristics of CAFs in PCa through bioinformatics analysis and built a CAFs-based risk model to predict prognostic treatment and treatment response in PCa patients. First, we downloaded the scRNA-seq data for PCa from the GEO. We extracted bulk RNA-seq data for PCa from the TCGA and GEO and adopted “ComBat” to remove batch effects. Then, we created a Seurat object for the scRNA-seq data using the package “Seurat” in R and identified CAF clusters based on the CAF-related genes (CAFRGs). Based on CAFRGs, a prognostic model was constructed by univariate Cox, LASSO, and multivariate Cox analyses. And the model was validated internally and externally by Kaplan–Meier analysis, respectively. We further performed GO and KEGG analyses of DEGs between risk groups. Besides, we investigated differences in somatic mutations between different risk groups. We explored differences in the immune microenvironment landscape and ICG expression levels in the different groups. Finally, we predicted the response to immunotherapy and the sensitivity of antitumour drugs between the different groups. We screened 4 CAF clusters and identified 463 CAFRGs in PCa scRNA-seq. We constructed a model containing 10 prognostic CAFRGs by univariate Cox, LASSO, and multivariate Cox analysis. Somatic mutation analysis revealed that TTN and TP53 were significantly more mutated in the high-risk group. Finally, we screened 31 chemotherapeutic drugs and targeted therapeutic drugs for PCa. In conclusion, we identified four clusters based on CAFs and constructed a new CAFs-based prognostic signature that could predict PCa patient prognosis and response to immunotherapy and might suggest meaningful clinical options for the treatment of PCa.

Increased RUNX3 expression mediates tumor-promoting ability of human breast cancer-associated fibroblasts.

Cancer-associated fibroblasts (CAFs) are a major stromal component of human breast cancers and often promote tumor proliferation, progression and malignancy. We previously established an experimental CAF (exp-CAF) cell line equipped with a potent tumor-promoting ability. It was generated through prolonged incubation of immortalized human mammary fibroblasts with human breast cancer cells in a tumor xenograft mouse model. Herein, we found that the exp-CAFs highly express Runt-related transcription factor 3 (RUNX3), while counterpart fibroblasts do not. In breast cancer patients, the proportion of RUNX3-positive stromal fibroblast-like cells tends to be higher in cancerous regions than in non-cancerous regions. These findings suggest an association of RUNX3 with CAF characteristics in human breast cancers. To investigate the functional role of RUNX3 in CAFs, the exp-CAFs with or without shRNA-directed knockdown of RUNX3 were implanted with breast cancer cells subcutaneously in immunodeficient mice. Comparison of the resulting xenograft tumors revealed that tumor growth was significantly attenuated when RUNX3 expression was suppressed in the fibroblasts. Consistently, Ki-67 and CD31 immunohistochemical staining of the tumor sections indicated reduction of cancer cell proliferation and microvessel formation in the tumors formed with the RUNX3-suppressed exp-CAFs. These results suggest that increased RUNX3 expression could contribute to the tumor-promoting ability of CAFs through mediating cancer cell growth and neoangiogenesis in human breast tumors.

Single-cell and bulk RNA sequencing reveal cancer-associated fibroblast heterogeneity and a prognostic signature in prostate cancer.

Cancer-associated fibroblasts (CAFs), the central players in the tumor microenvironment (TME), can promote tumor progression and metastasis via various functions. However, the properties of CAFs in prostate cancer (PCa) have not been fully assessed. Therefore, we aimed to examine the CAF characteristics in PCa and construct a CAF-derived signature to predict PCa prognosis. CAFs were identified using single-cell RNA sequencing (scRNA-seq) data from 3 studies. We performed the FindAllMarkers function to extract CAF marker genes and constructed a signature to predict the biochemical relapse-free survival (bRFS) of PCa in the Cancer Genome Atlas (TCGA) cohort. Subsequently, different algorithms were applied to reveal the differences of the TME, immune infiltration, treatment responses in the high- and low-risk groups. Additionally, the CAF heterogeneity was assessed in PCa, which were confirmed by the functional enrichment analysis, gene set enrichment analysis (GSEA), and AUCell method. The scRNA-seq analysis identified a CAF cluster with 783 cells and determined 183 CAF marker genes. Cell-cell communication revealed extensive interactions between fibroblasts and immune cells. A CAF-related prognostic model, containing 7 genes (ASPN, AEBP1, ALDH1A1, BGN, COL1A1, PAGE4 and RASD1), was developed to predict bRFS and validated by 4 independent bulk RNA-seq cohorts. Moreover, the high-risk group of the signature score connected with an immunosuppressive TME, such as a higher level of M2 macrophages and lower levels of plasma cells and CD8+ T cells, and a reduced reaction rate for immunotherapy compared with low-risk group. After re-clustering CAFs via unsupervised clustering, we revealed 3 biologically distinct CAF subsets, namely myofibroblast-like CAFs (myCAFs), immune and inflammatory CAFs (iCAFs) and antigen-presenting CAFs (apCAFs). In conclusion, the CAF-derived signature, the first of its kind, can effectively predict PCa prognosis and serve as an indicator for immunotherapy. Furthermore, our study identified 3 CAF subpopulations with distinct functions in PCa.

Identification and validation of cancer-associated fibroblast-related subtypes and the prognosis model of biochemical recurrence in prostate cancer based on single-cell and bulk RNA sequencing.

Cancer-associated fibroblasts (CAFs) are an essential component of the tumor immune microenvironment that are involved in extracellular matrix (ECM) remodeling. We aim to investigate the characteristics of CAFs in prostate cancer and develop a biochemical recurrence (BCR)-related CAF signature for predicting the prognosis of PCa patients. The bulk RNA-seq and relevant clinical information were obtained from the TCGA and GEO databases, respectively. The infiltration scores of CAFs in prostate cancer patients were calculated using the MCP counter and EPIC algorithms. The single-cell RNA sequencing (scRNA-seq) was downloaded from the GEO database. Subsequently, univariate Cox regression analysis was employed to identify prognostic genes associated with CAFs. We identified two subtypes (C1 and C2) of prostate cancer that were associated with CAFs via non-negative matrix factorization (NMF) clustering. In addition, the BCR-related CAF signatures were constructed using Lasso regression analysis. Finally, a nomogram model was established based on the risk score and clinical characteristics of the patients. Initially, we found that patients with high CAF infiltration scores had shorter biochemical recurrence-free survival (BCRFS) times. Subsequently, CAFs in four pairs of tumors and paracancerous tissues were identified. We discovered 253 significantly differentially expressed genes, of which 13 had prognostic significance. Using NMF clustering, we divided PCa patients into C1 and C2 subgroups, with the C1 subgroup having a worse prognosis and substantially enriched cell cycle, homologous recombination, and mismatch repair pathways. Furthermore, a BCR-related CAFs signature was established. Multivariate COX regression analysis confirmed that the BCR-related CAFs signature was an independent prognostic factor for BCR in PCa. In addition, the nomogram was based on the clinical characteristics and risk scores of the patient and demonstrated high accuracy and reliability for predicting BCR. Lastly, our findings indicate that the risk score may be a useful tool for predicting PCa patients' sensitivity to immunotherapy and drug treatment. NMF clustering based on CAF-related genes revealed distinct TME immune characteristics between groups. The BCR-related CAF signature accurately predicted prognosis and immunotherapy response in prostate cancer patients, offering a promising new approach to cancer treatment.

Isolation and characterization of cancer-associated fibroblasts in the tumor microenvironment of hepatocellular carcinoma.

Cancer-associated fibroblasts (CAFs) play an immunosuppressive role in the tumor microenvironment (TME) of human cancers; however, their characteristics and role in hepatocellular carcinoma (HCC) remain to be elucidated. Nine tumor and surrounding liver tissue samples from patients with HCC who underwent surgery were used to isolate patient-derived CAFs. Cell morphology was observed using an optical microscope after culture, and cell phenotypes were evaluated using flow cytometry and immunoblotting. Cytokines secreted by CAFs into culture medium were quantified using a multiplex cytokine assay. CAFs were abundant in the TME of HCC and were adjacent to immune cells. After culture, the CAFs and non-tumor fibroblasts exhibited spindle shapes. We observed a robust expression of alpha-smooth muscle actin and fibroblast activation protein in CAFs, whereas alpha-fetoprotein, epithelial cell adhesion molecule, platelet/endothelial cell adhesion molecule-1, and E-cadherin were not expressed in CAFs. Furthermore, CAFs showed high secretion of various cytokines, namely C-X-C motif chemokine ligand 12, interleukin (IL)-6, IL-8, and C-C motif chemokine ligand 2. CAFs are abundant in the TME of HCC and play a crucial role in tumor progression. These fibroblasts secrete cytokines that promote tumor growth and metastasis.

Isolation and characterization of cancer-associated fibroblasts in the tumor microenvironment of hepatocellular carcinoma

Isolation and characterization of cancer-associated fibroblasts in the tumor microenvironment of hepatocellular carcinoma

A novel signature predicts prognosis and immunotherapy in lung adenocarcinoma based on cancer-associated fibroblasts.

Extensive research has established the significant correlations between cancer-associated fibroblasts (CAFs) and various stages of cancer development, including initiation, angiogenesis, progression, and resistance to therapy. In this study, we aimed to investigate the characteristics of CAFs in lung adenocarcinoma (LUAD) and develop a risk signature to predict the prognosis of patients with LUAD. We obtained single-cell RNA sequencing (scRNA-seq) and bulk RNA-seq data from the public database. The Seurat R package was used to process the scRNA-seq data and identify CAF clusters based on several biomarkers. CAF-related prognostic genes were further identified using univariate Cox regression analysis. To reduce the number of genes, Lasso regression was performed, and a risk signature was established. A novel nomogram that incorporated the risk signature and clinicopathological features was developed to predict the clinical applicability of the model. Additionally, we conducted immune landscape and immunotherapy responsiveness analyses. Finally, we performed in vitro experiments to verify the functions of EXO1 in LUAD. We identified 5 CAF clusters in LUAD using scRNA-seq data, of which 3 clusters were significantly associated with prognosis in LUAD. A total of 492 genes were found to be significantly linked to CAF clusters from 1731 DEGs and were used to construct a risk signature. Moreover, our immune landscape exploration revealed that the risk signature was significantly related to immune scores, and its ability to predict responsiveness to immunotherapy was confirmed. Furthermore, a novel nomogram incorporating the risk signature and clinicopathological features showed excellent clinical applicability. Finally, we verified the functions of EXP1 in LUAD through in vitro experiments. The risk signature has proven to be an excellent predictor of LUAD prognosis, stratifying patients more appropriately and precisely predicting immunotherapy responsiveness. The comprehensive characterization of LUAD based on the CAF signature can predict the response of LUAD to immunotherapy, thus offering fresh perspectives into the management of LUAD patients. Our study ultimately confirms the role of EXP1 in facilitating the invasion and growth of tumor cells in LUAD. Nevertheless, further validation can be achieved by conducting in vivo experiments.

Integrating single-cell and bulk RNA sequencing to develop a cancer-associated fibroblast-related signature for immune infiltration prediction and prognosis in lung adenocarcinoma.

An accumulating amount of studies are highlighting the impacts of cancer-associated fibroblasts (CAFs) on the initiation, metastasis, invasion, and immune evasion of lung cancer. However, it is still unclear how to tailor treatment regimens based on the transcriptomic characteristics of CAFs in the tumor microenvironment of patients with lung cancer. Our study examined single-cell RNA-sequencing data from the Gene Expression Omnibus (GEO) database to identify expression profiles for CAF marker genes and constructed a prognostic signature of lung adenocarcinoma using these genes in The Cancer Genome Atlas (TCGA) database. The signature was validated in 3 independent GEO cohorts. Univariate and multivariate analyses were used to confirm the clinical significance of the signature. Next, multiple differential gene enrichment analysis methods were used to explore the biological pathways related to the signature. Six algorithms were used to assess the relative proportion of infiltrating immune cells, and the relationship between the signature and immunotherapy response of lung adenocarcinoma (LUAD) was explored based on the tumor immune dysfunction and exclusion (TIDE) algorithm. The signature related to CAFs in this study showed good accuracy and predictive capacity. In all clinical subgroups, the high-risk patients had a poor prognosis. The univariate and multivariate analyses confirmed that the signature was an independent prognostic marker. Moreover, the signature was closely associated with particular biological pathways related to cell cycle, DNA replication, carcinogenesis, and immune response. The 6 algorithms used to assess the relative proportion of infiltrating immune cells indicated that a lower infiltration of immune cells in the tumor microenvironment was associated with high-risk scores. Importantly, we found a negative correlation between TIDE, exclusion score, and risk score. Our study constructed a prognostic signature based on CAF marker genes useful for prognosis and immune infiltration estimation of lung adenocarcinoma. This tool could enhance therapy efficacy and allow individualized treatments.

Morphodynamic and motility feature-based deep learning classification for subtypes of cancer-associated fibroblasts.

The cancer-associated fibroblasts (CAFs) have risen to prominence as key players in cancer progression. It is now widely appreciated that CAFs are composed of heterogeneous populations, either pro-tumorigenic or anti-tumorigenic. In addition, a growing body of evidence supports the multifaceted nature of CAFs. Therefore, researchers in the field have been trying to identify subtypes of CAFs with molecular markers. However, those markers cannot accurately classify the subpopulations and can be co-expressed in different subtypes. In order to utilize CAFs as a target for cancer treatment, issues with subtypes of CAFs must be resolved such that specific pro-tumorigenic subtypes can be suppressed or reprogrammed to anti-tumorigenic ones. The morphology and the motile characteristics of CAFs result from gene expression combinations. Thus, those characteristics can be holistic readouts of CAFs. Unlike biomolecular analysis, a fixed cell-based end-point assay, morphology or motility features of cells can be traced with live-cell imaging. Those features can provide information on the dynamic changes of CAFs. Here, in order to comprehensively identify subtypes CAFs, we adopt a deep learning-based cell classification strategy. Using multiple unsupervised and supervised machine learning algorithms, we extract the morphodynamic and motility features of cells from label-free live-cell imaging data of CAFs. To this end, we established in vitro breast CAFs, which were fibroblasts cocultured with two different breast cancer cell lines with different aggressiveness. As a result, we show that the morphodynamic and motility features can successfully classify heterogeneous subpopulations of cells.

The Role of Mitochondrial RNA from B-Precursor Acute Lymphoblastic Leukaemia Cells in Generating a Chemoprotective Bone Marrow Niche

Treatment resistant cells in precursor B-cell Acute Lymphoblastic Leukaemia (B-ALL) likely reside in a protective bone marrow niche with nestin-expressing mesenchymal stromal cells (MSC) (Duan et al Cancer Cell 2014). Previous work from our laboratory demonstrated that an 'activated MSC' niche, in which MSC have acquired features of cancer associated fibroblasts (CAF), develops in response to reactive oxygen species (ROS)-inducing chemotherapy. Mitochondria are actively transferred along tunneling nanotubes from activated MSC to B-ALL cells and can 'rescue' the cells from chemotherapy (Burt, et al Blood 2019). However, work from other groups suggests that chemoresistant ALL sub-clones exist prior to chemotherapy exposure, carrying a gene expression signature enriched for stemness, mitochondrial metabolism, stress responses and chromatin remodelling (Dobson et al Cancer Discovery 2020). We hypothesised that B-ALL cells may themselves directly activate bone marrow stromal cells and induce niche-formation prior to treatment, leading to ab-inito chemoresistance. To test this hypothesis, we first used our previously-described, in vitro niche model wherein either the HS27a MSC cell line or healthy donor MSCs were co-cultured with either B-ALL cell lines or primary patient B-ALL cells. Three of the five B-ALL cell lines and three of the four primary B-ALL samples that were tested induced activation of the MSCs, as characterised by cytomorphological changes identified by confocal microscopy, up-regulation of CAF-relevant gene expression and increased IL6, IL8 and CCL2 protein secretion. The ability of the B-ALL cell lines to activate MSC correlated directly with the intrinsic ROS level of the cell as determined by CellROX assay. Mitochondrial transfer from the cell-activated MSC to B-ALL cells, as measured by mitotracker dye transfer, occurred exactly as we had seen when we had used chemotherapy to activate the stroma. In vivo, the MSC-activating ALL cell lines also activated murine MSCs when established as xenografts in NOD-SCID gamma (NSG) mice. Immunohistochemistry of NSG murine femora revealed a very significant expansion in nestin+ cells after exposure to niche-induing ALL cells compared to non-niche-inducing controls. We aimed to determine the mechanism behind the B-ALL induced MSC activation. We determined that it was contact-independent, arising from exposure of MSC to ALL cells in transwell but also from exposure to B-ALL cell conditioned media alone. RNA sequencing of MSC after treatment with conditioned medium from activating B-ALL cells compared with non-activating controls unexpectedly showed that most highly upregulated pathways in the MSC-activating scenario were those involved in RNA sensing. Thus, we sought evidence for the role of mitochondrial dsRNA, as it had been recently shown to activate the anti-viral signalling pathway (Dhir et al, Nature 2018). Using the J2 anti-double stranded (ds) RNA monoclonal antibody in both confocal and flow cytometric assays, we observed very significantly higher levels of dsRNA in MSC which had been exposed to stromal-activating B-ALL cell conditioned medium than in non-activating B-ALL or MSC alone controls (see panel for image). We used the small molecule VBIT4, a voltage-dependent anion channel oligomerization inhibitor that decreases mitochondrial nucleic acid release to block this phenomenon in B-ALL cells. We quantified expression of a selection of stromal cell activation marker genes as well as genes in the RNA sensing pathway after treatment with VBIT4-exposed B-ALL cell CM or non-treated control. We observed a 2 to 4-fold reduction in expression of IL6 and CCL2 after VBIT4 exposure, compared to control. In the stromal cell RNA sensing pathway, there was a 15-fold reduction in expression of RIG-I and a 2 to 4-fold reduction in the interferon pathway genes MX2, IFIH1, MAVS and OAS1. Experiments to determine whether knock down of components of the antiviral sensing pathway also abrogates stromal activation and further murine experiments are ongoing. We propose a model in which ROS-induced mitochondrial dysfunction leads to release of dsRNA which in turn activates bone marrow stromal cells leading to protective niche formation and chemoprotection of acute lymphoblastic leukaemia cells despite lack of prior exposure to cytotoxic agents. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

T026: Characterization of cancer-associated fibroblasts in classical Hodgkin lymphoma

Background: Cancer-associated fibroblasts (CAFs) are a heterogeneous cell population with diverse functions. They constitute an important stromal component of the tumor microenvironment (TME), regulate immune responses and promote tumor growth. We have earlier characterized the immunoprofile of cHL and concluded that high proportions of checkpoint protein positive immune cells associated with unfavorable overall survival (OS). Here, we have characterized distinct CAF subsets and their clinical impact in cHL. Methods: CAFs, tumor associated macrophages (TAMs), T cells and checkpoint molecules were phenotyped from the diagnostic cHL samples (n=131) using multiplex immunohistochemistry with digital image analysis. Platelet-derived growth factor receptor (PDGFR) α and β, fibroblast-activation protein (FAP) and α-smooth muscle actin (α-SMA) were utilized as CAF markers. Nanostring-based data from a 770-gene immune panel was used to correlate CAF proportions with gene expression. Results: Median age of the patients was 30 years, 78% had nodular sclerosis subtype and 56% advanced stage. Primary treatment (85%) was mostly doxorubicin, bleomycin, vinblastine, dacarbazine, and in limited stage, in combination with radiotherapy. At the median follow-up time of 55 months, 22% of the patients relapsed and 8% died. Five-year freedom from treatment failure (FFTF) was 79% and OS 91%. From all cells in the TME, 20% were PDGFRβ (range 0.2–92%), 19% FAP (range 0–88%), 16% α-SMA (range 2–56%), and 1% PDGFRα (range 0.1–58%) positive. High proportion of FAP+ cells associated with inferior FFTF (HR 1.25, 95%CI 1.0–1.5, P=0.020). In a small subgroup of patients, PDGFRα and FAP were expressed on the same cells defining an PDGFRα+FAP+ double positive cHL phenotype, which translated to better outcome (5-y FFTF 100 % vs. 76%, P=0.035; 5-y OS 100% vs. 90%, P=0.270). Clinical characteristics were equally distributed between these subgroups. PDGFRα+FAP+ phenotype associated positively with high proportion of TAMs (P=0.026), but negatively with T cells (P=0.006) and checkpoint molecule indoleamine 2,3 dioxygenase 1 (IDO-1)+ cells (P=0.002). In addition, focal adhesion and extracellular matrix pathway genes were enriched in PDGFRα+FAP+ cHLs. Conclusion: Our data identifies distinct CAF subsets in cHL and suggests that the newly characterized subset of PDGFRα+FAP+ CAFs has prognostic impact in cHL patients. Validation of the results is ongoing.

Wentilactone A Reverses the NF-κB/ECM1 Signaling-Induced Cisplatin Resistance through Inhibition of IKK/IκB in Ovarian Cancer Cells.

Wentilactone A (WA) is a tetranorditerpenoid isolated from marine algae. We previously found that WA inhibited cancer cell proliferation with little toxicity. In this study, we show that high expression of extracellular matrix protein-1 (ECM1) promotes cancer cell cisplatin resistance, and the secreted ECM1 activates normal fibroblasts (NFs) to transform cells with characteristics of cancer-associated fibroblasts (CAFs). Transcription of the ECM1 gene is regulated largely by NF-κB through EP881C/T-EP266C binding sites. WA supresses the phosphorylation of NF-κB through inhibition of the upstream IKK/IκB phoshorylation to block the expression of ECM1, which reverses the cisplatin-induced activation of NF-κB/ECM1. On the contrary, cisplatin facilitates phosphorylation of NF-κB to enhance the expression of ECM1. These results highlight ECM1 as a potential target for treatment of cisplatin-resistant cancers associated with the ECM1 activated signaling. In addition, WA reverses cisplatin resistance by targeting both tumor cells and the tumor microenvironment through IKK/IκB/NF-κB signaling to reduce the expression of the ECM1 protein.

CGAS-STING signaling encourages immune cell overcoming of fibroblast barricades in pancreatic cancer

Immune checkpoint blockade (ICB) treatment improves the prognosis of several types of solid tumors, however, responsiveness to ICB therapy remains low in pancreatic ductal adenocarcinoma (PDACs), which has a rich tumor microenvironment (TME). The TME is composed of various stromal cells, including cancer-associated fibroblasts (CAFs), which contribute to the establishment of an immunosuppressive microenvironment. The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway is an innate immune pathway that results in the upregulation of immune cell recruiting-cytokines and anti-tumor efficacy. In this study, we aimed to investigate the impact of cGAS-STING expression and the presence of CAFs upon immune cell infiltration in PDACs. cGAS and STING co-expressing PDAC cases showed favorable survival, with many cytotoxic CD8 + T cell infiltrations from the stromal component adjacent to the cancer cells toward cancer cells, but not in cGAS-STING signaling defected PDAC cases. The signatures of tumor-restrain CAFs were expressed in tumors with cGAS-STING signaling. Finally, transwell co-culture experiments demonstrated that immune cell infiltration was impeded by the presence of CAFs, but not by activation of cGAS-STING signaling. In conclusion, pro-infiltration signals, such as cGAS-STING, and characterization of CAFs are crucial in defeating CAF barricades and encouraging immune cell infiltration in PDACs.

Molecular Characterization of Cancer Associated Fibroblasts in Prostate Cancer.

Simple SummaryPrimary, organ-confined prostate cancer is treatable with surgery, chemotherapy, radiation, and active surveillance; however, a subset of patients will develop metastatic disease. The main issue in prostate cancer is the need of prognostic tools for identifying patients at risk for lethal metastatic tumor, as well as a lack of curative therapies for such patients. The tissues surrounding the prostate cancer cells consist of a mixture of stromal cells that are structurally and functionally different from stromal cells in normal prostate. The stromal component, as a source of prognostic information for metastatic disease progression, has received little attention. In the present study, we characterized stromal cells from cancer tissues as compared to stromal cells from normal adjacent tumor tissue or human benign prostate. The stroma’s specific profile will allow to predict the presence of aggressive tumors, therapy resistance, and metastasis development. Background: Stromal components surrounding epithelial cancer cells seem to play a pivotal role during epithelial-to-mesenchymal transition (EMT), tumor invasion, and metastases. To identify the molecular mechanisms underlying tumor–stroma interactions may yield novel therapeutic targets for prostate cancer. Methods: Gene expression profile of prostate-cancer associated fibroblast (PCAF) and prostate non-cancer associated fibroblast (PNAF) cells isolated from radical prostatectomy was performed by Illumina, analyzed, and further processed by Ingenuity®: IPA® software. qRT-PCR was performed on an independent set of 17 PCAF, 12 PNAF, and 12 fibroblast cell lines derived from patients with benign prostatic hyperplasia (BPHF). Results: Using microarray analysis, we found six upregulated genes and two downregulated genes in PCAFs compared to PNAFs. To validate microarray results, we performed qRT-PCR for the most significantly regulated genes involved in the modulation of proliferation and androgen resistance on an independent set of PNAF, PCAF, and BHPF samples. We confirmed the increased expression of SCARB1, MAPK3K1, and TGF-β as well as the decreased expression of S100A10 in PCAFs compared to PNAFs and BPHFs. Conclusions: These results provide strong evidence that the observed changes in the gene expression profile of PCAFs can contribute to functional alteration of adjacent prostate cancer cells.