Cancer-associated Fibroblasts Formation Research Articles

Huaier-induced suppression of cancer-associated fibroblasts confers immunotherapeutic sensitivity in triple-negative breast cancer

BackgroundTriple-negative breast cancer (TNBC) is the most intractable subgroup of breast neoplasms due to its aggressive nature. In recent years, immune checkpoint inhibitors (ICIs) have exhibited potential efficacy in TNBC treatment. However, only a limited fraction of patients benefit from ICI therapy, primarily because of the suppressive tumor immune microenvironment (TIME). Trametes robiniophila Murr (Huaier) is a traditional Chinese medicine (TCM) with potential immunoregulatory functions. However, the underlying mechanism remains unclear. PurposeThe present study aimed to investigate the therapeutic role of Huaier in the TIME of TNBC patients. MethodsSingle-cell RNA sequencing (scRNA-seq) was used to systematically analyze the influence of Huaier on the TNBC microenvironment for the first time. The mechanisms of the Huaier-induced suppression of cancer-associated fibroblasts (CAFs) were assessed via real-time quantitative polymerase chain reaction (qRT‒PCR) and western blotting. A tumor-bearing mouse model was established to verify the effects of the oral administration of Huaier on immune infiltration. ResultsUnsupervised clustering of the transcriptional profiles suggested an increase in the number of apoptotic cancer cells in the Huaier group. Treatment with Huaier induced immunological alterations from a "cold" to a "hot" state, which was accompanied by phenotypic changes in CAFs. Mechanistic analysis revealed that Huaier considerably attenuated the formation of myofibroblastic CAFs (myoCAFs) by impairing transforming growth factor-beta (TGF-β)/SMAD signaling. In mouse xenograft models, Huaier dramatically modulated CAF differentiation, thus synergizing with the programmed cell death 1 (PD1) blockade to impede tumor progression. ConclusionsOur findings demonstrate that Huaier regulates cancer immunity in TNBC by suppressing the transition of CAFs to myoCAFs and emphasize the crucial role of Huaier as an effective adjuvant agent in immunotherapy.

Targeting MCM2 activates cancer-associated fibroblasts-like phenotype and affects chemo-resistance of liposarcoma cells against doxorubicin.

Liposarcoma is one of the most common soft tissue malignancies. We previously discovered upregulation of minichromosome maintenance 2 (MCM2) expression in liposarcoma tissues. Hereon, we attempt to clarify the biological influence and mechanisms of MCM2 in liposarcoma. The mRNA level of MCM2 expression was detected through the use of quantitative real-time PCR. Immunohistochemistry staining and western blot were employed to detect protein expression of MCM2. The protein expression of fibroblast-activation protein and α-smooth muscle actin was examined by immunofluorescence. Protein concentrations of interleukin (IL)-6, transforming growth factor β, and IL-8 were measured via ELISA. Furthermore, liposarcoma cell viability was assessed through cell counting kit-8 assay, and liposarcoma cell invasiveness and migration were evaluated through transwell assay. For assessing proliferation and apoptosis of liposarcoma cells, colony formation assay and flow cytometry were used. For constructing a mouse tumor model, SW872 cells were introduced into mouse flank via subcutaneous injection. MCM2 expression was boosted in liposarcoma tissues and cells when compared with the controls. MCM2-activated cancer-associated fibroblasts (CAFs)-like phenotype, presenting as increased fibroblast-activation protein expression, α-smooth muscle actin expression, cell migration, IL-6 concentration, IL-8 concentration, and transforming growth factor β concentration. Functional experiments indicated that MCM2-activated-CAFs facilitated proliferation, migration, and invasion of liposarcoma cells. Additionally, 1 μM doxorubicin treatment could not affect proliferation and apoptosis of liposarcoma cells, whereas combined use of MCM2 knockdown and 1 μM doxorubicin evidently repressed cell proliferation and promoted apoptosis. In vivo, silencing of MCM2 impaired tumor growth in mice. MCM2 overexpression promoted CAFs formation and tumor progression, showing potential value in treatment of liposarcoma.

Molecular and epigenetic ex vivo profiling of testis cancer-associated fibroblasts and their interaction with germ cell tumor cells and macrophages

Germ cell tumors (GCT) are the most common solid tumors in young men of age 15 - 40. In previous studies, we profiled the interaction of GCT cells with cells of the tumor microenvironment (TM), which showed that especially the 3D interaction of fibroblasts (FB) or macrophages with GCT cells influenced the growth behavior and cisplatin response as well as the transcriptome and secretome of the tumor cells, suggesting that the crosstalk of these cells with GCT cells is crucial for tumor progression and therapy outcome.In this study, we shed light on the mechanisms of activation of cancer-associated fibroblasts (CAF) in the GCT setting and their effects on GCT cells lines and the monocyte cell line THP-1. Ex vivo cultures of GCT-derived CAF were established and characterized molecularly and epigenetically by performing DNA methylation arrays, RNA sequencing, and mass spectrometry-based secretome analysis.We demonstrated that the activation state of CAF is influenced by their former prevailing tumor environment in which they have resided. Hereby, we postulate that seminoma (SE) and embryonal carcinoma (EC) activate CAF, while teratoma (TER) play only a minor role in CAF formation. In turn, CAF influence proliferation and the expression of cisplatin sensitivity-related factors in GCT cells lines as well as polarization of in vitro-induced macrophages by the identified effector molecules IGFBP1, LGALS3BP, LYVE1, and PTX3.Our data suggests that the vital interaction of CAF with GCT cells and with macrophages has a huge influence on shaping the extracellular matrix as well as on recruitment of immune cells to the TM. In conclusion, therapeutically interfering with CAF and / or macrophages in addition to the standard therapy might slow-down progression of GCT and re-shaping of the TM to a tumor-promoting environment.Significance: The interaction of CAF with GCT and macrophages considerably influences the microenvironment. Thus, therapeutically interfering with CAF might slow-down progression of GCT and re-shaping of the microenvironment to a tumor-promoting environment.

Tumor cell-intrinsic epigenetic SETpoint of cancer-associated fibroblasts

Cancer-associated fibroblasts (CAFs) exhibit spatial and functional diversity. Here, Niu etal. unveil SETD2's function in lipid metabolism and CAF heterogeneity in pancreatic ductal adenocarcinoma. SETD2 deficiency boosts oxidative phosphorylation activity, prompting lipid-laden CAF formation through BMP2 signaling, offering promising therapeutic avenues in personalized cancer treatment.

Differences Between Edges and Centers of Melanomas Using Vibrational Optical Coherence Tomography: The Effects of Critical Lesion Size

Vibrational Optical Coherence Tomography (VOCT) is a new technique to noninvasively characterize skin cancers. We have previously shown that skin cancers exhibit new mechanovibrational peaks at 80, 130, and 250-260 Hz. The 80 Hz peak appears to represent new cells including Cancer Associated Fibroblasts (CAFs) while the new 130 and 250-260 Hz peaks reflect thin blood vessels and fibrotic tissue, respectively. Epithelial cell derived cancers are characterized by the formation of CAFs that are stiffer than normal fibroblasts, induce deposition of new thin vasomimictry vessels, and influence fibrotic tissue formation by expression of lysyl oxidases. The results of this study suggest that small lesions less than 0.13 mm in diameter are found in clear margins of skin cancers while lesions greater than 0.21 mm in diameter are characteristic of cancerous tissue based on histopathology. The results of this study suggest that early detection of MEL lesions as small as 0.06 mm can be achieved noninvasively using VOCT. VOCT may provide a method of screening patients for skin cancer in remote areas where Dermatologists are unavailable through use of telemedicine.

Role of autophagy in cancer-associated fibroblast activation, signaling and metabolic reprograming.

Tumors not only consist of cancerous cells, but they also harbor several normal-like cell types and non-cellular components. cancer-associated fibroblasts (CAFs) are one of these cellular components that are found predominantly in the tumor stroma. Autophagy is an intracellular degradation and quality control mechanism, and recent studies provided evidence that autophagy played a critical role in CAF formation, metabolic reprograming and tumor-stroma crosstalk. Therefore, shedding light on the autophagy and its role in CAF biology might help us better understand the roles of CAFs and the TME in cancer progression and may facilitate the exploitation of more efficient cancer diagnosis and treatment. Here, we provide an overview about the involvement of autophagy in CAF-related pathways, including transdifferentiation and activation of CAFs, and further discuss the implications of targeting tumor stroma as a treatment option.

PDGF-BB accelerates TSCC via fibroblast lactates limiting miR-26a-5p and boosting mitophagy

The tumor microenvironment and cancer-associated fibroblasts (CAFs) play crucial roles in tumor development, and their metabolic coupling remains unclear. Clinical data showed a positive correlation between PDGF-BB, CAFs, and glycolysis in the tumor microenvironment of oral tongue squamous cell carcinoma patients. In vitro, CAFs are derived from hOMF cells treated with PDGF-BB, which induces their formation and promotes aerobic glycolysis. Mitophagy increased the PDGF-BB-induced formation of CAF phenotypes and aerobic glycolysis, while autophagy inhibition blocked PDGF-BB-induced effects. Downregulation of miR-26a-5p was observed in CAFs; upregulation of miR-26a-5p inhibited the expression of mitophagy-related proteins ULKI, Parkin, PINK1, and LC3 and aerobic glycolysis in PDGF-BB-induced CAFs. PDGF-BB-induced CAFs promoted tumor cell proliferation, invasion, metastasis, NF-κB signaling pathway activation, and PDGF-BB secretion. Thus, PDGF-BB is associated with lactate-induced CAF formation and glucose metabolism reprogramming. These findings indicate potential therapeutic targets in oral tongue squamous cell carcinoma.

Exosomes-mediated transfer of LINC00691 regulates the formation of CAFs and promotes the progression of gastric cancer

ObjectiveGastric cancer (GC) is one of the malignant tumors with the highest mortality worldwide. Our previous studies have revealed that LINC00691 is up-regulated in serum of GC patients as a novel potential biomarker for GC diagnosis and prognosis. However, the roles of serum exosomal LINC00691 in GC has not been clarified. This study aimed to find the expression pattern of serum exosomal LINC00691 in GC patients and the correlation between the level of serum exosomal LINC00691 and the pathology of gastric cancer patients.MethodsWe collected the serum of 94 GC patients before surgery and extracted exosomes to detect the expression level of exosomal LINC00691, with 21 healthy volunteers and 17 patients with benign gastric diseases as controls. Surgical GC tissues and paired healthy tissues were collected to culture primary cancer-associated fibroblasts (CAFs) and normal fibroblasts (NFs). We then treated NFs with LINC00691-rich GC cell culture supernatant or exosomes and detected the activation markers and biological functions of the fibroblasts.ResultsThe results of real-time qPCR indicated that the serum exosomal LINC00691 of GC patients was significantly higher than that of healthy subjects and patients with benign gastric diseases, and was associated with the clinicopathology of GC patients. More interestingly, when the NFs were treated with GC exosomes, the level of LINC00691 was significantly increased, the cell proliferation and migration were noticeably enhanced, and the ability to accelerate GC cell proliferation and invasion was promoted, which means that the induced fibroblasts gained the properties of CAFs. In addition, we found that knockdown of LINC00691 and the use of the JAK2/STAT3 signaling pathway inhibitor ruxolitinib effectively deprived exosome-containing GC cell supernatants of the effects on NFs.ConclusionOur study suggested that exosomal LINC00691 promoted NFs to gained the properties of CAFs depending on JAK2/STAT3 signaling pathway as a potential diagnostic biomarker for GC.

Hepatocellular carcinoma cells remodel the pro-metastatic tumour microenvironment through recruitment and activation of fibroblasts via paracrine Egfl7 signaling

BackgroundThe tumour microenvironment consists of a complex and dynamic milieu of cancer cells, including tumour-associated stromal cells (leukocytes, fibroblasts, vascular cells, etc.) and their extracellular products. During invasion and metastasis, cancer cells actively remodel the tumour microenvironment and alterations of microenvironment, particularly cancer-associated fibroblasts (CAFs), can promote tumour progression. However, the underlying mechanisms of the CAF formation and their metastasis-promoting functions remain unclear.MethodsPrimary liver fibroblasts and CAFs were isolated and characterized. CAFs in clinical samples were identified by immunohistochemical staining and the clinical significance of CAFs was also analysed in two independent cohorts. A transwell coculture system was used to confirm the role of HCC cells in CAF recruitment and activation. qRT-PCR, western blotting and ELISA were used to screen paracrine cytokines. The role and mechanism of Egfl7 in CAFs were explored via an in vitro coculture system and an in vivo mouse orthotopic transplantation model.ResultsWe showed that CAFs in hepatocellular carcinoma (HCC) are characterized by the expression of α-SMA and that HCC cells can recruit liver fibroblasts (LFs) and activate them to promote their transformation into CAFs. High α-SMA expression, indicating high CAF infiltration, was correlated with malignant characteristics. It was also an independent risk factor for HCC survival and could predict a poor prognosis in HCC patients. Then, we demonstrated that EGF-like domain multiple 7 (Egfl7) was preferentially secreted by HCC cells, and exhibited high potential to recruit and activate LFs into the CAF phenotype. The ability of Egfl7 to modulate LFs relies upon increased phosphorylation of FAK and AKT via the receptor ανβ3 integrin. Strikingly, CAFs activated by paracrine Egfl7 could further remodel the tumour microenvironment by depositing fibrils and collagen and in turn facilitate HCC cell proliferation, invasion and metastasis.ConclusionOur data highlighted a novel role of Egfl7 in remodelling the tumour microenvironment: it recruits LFs and activates them to promote their transformation into CAFs via the ανβ3 integrin signaling pathway, which further promotes HCC progression and contributes to poor clinical outcomes in HCC patients.3o7rdHzTehVwN25qa8k-ATVideo

Colorectal cancer cells induce the formation of cancer-associated fibroblasts by activating the ERK signaling pathway in fibroblasts

To investigate the mechanism by which conditioned medium of colorectal cancer cells promotes the formation of cancer-associated fibroblasts (CAFs). Normal human colorectal fibroblasts (CCD-18Co cells) in logarithmic growth phase were treated with the conditioned media of colorectal cancer HCT116 cells (HCT116-CM) or Caco-2 cells (Caco-2-CM) alone or in combination with 300 nmol/L ERK inhibitor SCH772984. The expression levels of CAFs-related molecular markers were detected in the treated cells with real-time quantitative PCR (RT- qPCR) and immunofluorescence assay, and the changes in cell proliferation, colony formation and migration were assessed with RTCA, colony formation and wound healing assays; Western blotting was performed to detect the activated signaling pathways in the fibroblasts and the changes in CAFs formation after blocking of the signaling pathway. HCT116-CM and Caco-2-CM significantly upregulated mRNA expression levels of CAFs markers (including α-SMA, FAP, FN and TGF-β) in CCD-18Co cells, and strongly promoted fibroblast transformation into CAFs (P < 0.05). The two conditioned media also promoted the proliferation, colony formation and migration of CCD-18Co cells (P < 0.05) and significantly increased the levels of α-SMA protein and ERK phosphorylation in the cells (P < 0.05). The ERK inhibitor SCH772984 obviously inhibited the expression of α-SMA and the transformation of CCD-18Co cells into CAFs induced by the conditioned medium of colorectal cancer cells (P < 0.05). Colorectal cancer cells may induce the formation of colorectal CAFs by activating the ERK pathway in the fibroblasts.

Transformable prodrug nanoplatform via tumor microenvironment modulation and immune checkpoint blockade potentiates immunogenic cell death mediated cancer immunotherapy.

Rationale: Chemoimmunotherapy is a promising approach in cancer immunotherapy. However, its therapeutic efficacy is restricted by high reactive oxygen species (ROS) levels, an abundance of cancer-associated fibroblasts (CAFs) in tumor microenvironment (TME) as well as immune checkpoints for escaping immunosurveillance. Methods: Herein, a new type of TME and reduction dual-responsive polymersomal prodrug (TRPP) nanoplatform was constructed when the D-peptide antagonist (DPPA-1) of programmed death ligand-1 was conjugated onto the surface, and talabostat mesylate (Tab, a fibroblast activation protein inhibitor) was encapsulated in the watery core (DPPA-TRPP/Tab). Doxorubicin (DOX) conjugation in the chain served as an immunogenic cell death (ICD) inducer and hydrophobic part. Results: DPPA-TRPP/Tab reassembled into a micellar structure in vivo with TME modulation by Tab, ROS consumption by 2, 2'-diselanediylbis(ethan-1-ol), immune checkpoint blockade by DPPA-1 and ICD generation by DOX. This resolved the dilemma between a hydrophilic Tab release in the TME for CAF inhibition and intracellular hydrophobic DOX release for ICD via re-assembly in weakly acidic TME with polymersome-micelle transformation. In vivo results indicated that DPPA-TRPP/Tab could improve tumor accumulation, suppress CAF formation, downregulate regulatory T cells and promote T lymphocyte infiltration. In mice, it gave a 60% complete tumor regression ratio and a long-term immune memory response. Conclusion: The study offers potential in tumor eradication via exploiting an "all-in-one" smart polymeric nanoplatform.

Interferon-dependent SLC14A1+ cancer-associated fibroblasts promote cancer stemness via WNT5A in bladder cancer.

Cancer-associated fibroblasts (CAFs) play a role in response to cancer treatment and patient prognosis. CAFs show phenotypic and functional heterogeneity and differ widely in tumors of different tissue origin. Here, we use single-cell RNA sequencing of bladder cancer (BC) patient samples and report a CAF subpopulation characterized by overexpression of the urea transporter SLC14A1. This population is induced by interferon signaling and confers stemness to BC cells via the WNT5A paracrine pathway. Activation of cGAS-STING signaling in tumor cells drives interferon production, thereby revealing a link between cGAS-STING signaling and SLC14A1+ CAF differentiation. Furthermore, the inhibition of SLC14A1+ CAF formation via targeting of STAT1 or STING sensitizes tumor cells to chemotherapy. More important, BC patients with high proportions of intratumoral SLC14A1+ CAFs show cancer stage-independent poor outcome and a worse response rate to neoadjuvant chemotherapy or immunotherapy.

Comprehensive analysis of the expression profile and clinical implications of regulator of chromosome condensation 2 in pan-cancers.

The Regulator of Chromosome Condensation 2 (RCC2) is an important gene that regulates mitosis and cytoplasmic division in the cell cycle. Although there have been reported in several individual tumors, an integrative analysis of RCC2 and its clinical significance across diverse cancer types is poorly elucidated. In this study, we performed integrative bioinformatics analyses to profile the expression landscape and assess the prognostic value of RCC2 in pan-cancers. Correlations between RCC2 expression and tumor-infiltrating immune cells, tumor mutation burden (TMB), microsatellite instability (MSI), chemokine and their receptors were analyzed using TCGA, ESTIMATE algorithm, and TISIDB database. We also explored the potential molecular functions of RCC2 through functional enrichment analysis and protein interaction networks. We discovered that RCC2 was highly expressed in various tumor tissues and was closely associated with cancer prognosis. Different RCC2-associated immune infiltration patterns were exhibited in different tumor-infiltrating immune cells. In addition, the RCC2 had a potential role in regulating the tumor immune microenvironment and the formation of cancer-associated fibroblasts (CAFs). Meanwhile, RCC2 showed a significant correlation with TMB, MSI, chemokines and their receptors in different tumor types. The role of RCC2 as a clinical therapeutic target was further revealed from the perspective of the immune microenvironment. In conclusion, RCC2 is closely associated with tumorigenesis and cancer-immune infiltration, and could be a promising prognostic and therapeutic biomarker in diverse cancers.

Signaling pathways in cancer-associated fibroblasts: recent advances and future perspectives.

As a critical component of the tumor microenvironment (TME), cancer-associated fibroblasts (CAFs) play important roles in cancer initiation and progression. Well-known signaling pathways, including the transforming growth factor-β (TGF-β), Hedgehog (Hh), Notch, Wnt, Hippo, nuclear factor kappa-B (NF-κB), Janus kinase (JAK)/signal transducer and activator of transcription (STAT), mitogen-activated protein kinase (MAPK), and phosphoinositide 3-kinase (PI3K)/AKT pathways, as well as transcription factors, including hypoxia-inducible factor (HIF), heat shock transcription factor 1 (HSF1), P53, Snail, and Twist, constitute complex regulatory networks in the TME to modulate the formation, activation, heterogeneity, metabolic characteristics and malignant phenotype of CAFs. Activated CAFs remodel the TME and influence the malignant biological processes of cancer cells by altering the transcriptional and secretory characteristics, and this modulation partially depends on the regulation of signaling cascades. The results of preclinical and clinical trials indicated that therapies targeting signaling pathways in CAFs demonstrated promising efficacy but were also accompanied by some failures (e.g., NCT01130142 and NCT01064622). Hence, a comprehensive understanding of the signaling cascades in CAFs might help us better understand the roles of CAFs and the TME in cancer progression and may facilitate the development of more efficient and safer stroma-targeted cancer therapies. Here, we review recent advances in studies of signaling pathways in CAFs and briefly discuss some future perspectives on CAF research.

Abstract C039: An EGFR-activated subset of myofibroblastic cancer-associated fibroblasts supports local metastatic dissemination in pancreatic ductal adenocarcinoma

Abstract Pancreatic ductal adenocarcinoma (PDA) has a dismal prognosis and new therapies are needed. Cancer-associated fibroblasts (CAFs) can promote PDA progression and are recognized promising therapeutic targets. However, the ongoing characterization of PDA CAF heterogeneity and plasticity and the identification of potential tumor-restraining CAF populations have highlighted the need to further dissect the diverse biology of PDA CAFs to develop effective combination therapies. Using pancreatic organoid/fibroblast co-cultures and organoid-derived transplantation mouse models of PDA, we mechanistically investigated the signaling cascade downstream TGF-beta activation, which is a main driver of myofibroblastic CAF (myCAF) formation. We find that the EGFR/ERBB2 pathway is activated by TGF-beta in a subset of myCAFs, in both murine and human PDA, via amphiregulin induction and autocrine signaling. ERBB activation is important for the maintenance of this myCAF subset, with genetic and pharmacological inhibition of this pathway differentially affecting PDA CAF composition both in culture and mouse models. Importantly, analysis of lung cancer and breast cancer patient samples suggests that our observations in PDA are also relevant to these malignancies. Finally, we reveal a role of this EGFR-activated myCAF subset in promoting local metastatic dissemination in PDA and indicate new potential combination strategies. Our study highlights the need to better dissect PDA CAF heterogeneity also in populations typically considered to be tumor-restraining, in order to develop effective combination strategies for future clinical intervention. Our work also reveals how cancer-targeting therapies can directly affect the surrounding microenvironment with potential clinical implications for various malignancies. Citation Format: Gianluca Mucciolo, Joaquín Araos Henríquez, Sara Pinto Teles, Judhell Manansala, Wenlong Li, Eloise G. Lloyd, Priscilla Cheng, Giulia Biffi. An EGFR-activated subset of myofibroblastic cancer-associated fibroblasts supports local metastatic dissemination in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr C039.

Exosomal telomerase transcripts reprogram the microRNA transcriptome profile of fibroblasts and partially contribute to CAF formation

It is now well accepted that cancer cells change their microenvironment from normal to tumor-supportive state to provide sustained tumor growth, metastasis and drug resistance. These processes are partially carried out by exosomes, nano-sized vesicles secreted from cells, shuttled from donor to recipient cells containing a cargo of nucleic acids, proteins and lipids. By transferring biologically active molecules, cancer-derived exosomes may transform microenvironmental cells to become tumor supportive. Telomerase activity is regarded as a hallmark of cancer. We have recently shown that the transcript of human telomerase reverse transcriptase (hTERT), is packaged in cancer cells derived- exosomes. Following the engulfment of the hTERT transcript into fibroblasts, it is translated into a fully active enzyme [after assembly with its RNA component (hTERC) subunit]. Telomerase activity in the recipient, otherwise telomerase negative cells, provides them with a survival advantage. Here we show that exosomal telomerase might play a role in modifying normal fibroblasts into cancer associated fibroblasts (CAFs) by upregulating mathrm{alpha }SMA and Vimentin, two CAF markers. We also show that telomerase activity changes the transcriptome of microRNA in these fibroblasts. By ectopically expressing microRNA 342, one of the top identified microRNAs, we show that it may mediate the proliferative phenotype that these cells acquire upon taking-up exosomal hTERT, providing them with a survival advantage.

Hypoxia promotes an inflammatory phenotype of fibroblasts in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is characterized by an extensive fibroinflammatory stroma and often experiences conditions of insufficient oxygen availability or hypoxia. Cancer-associated fibroblasts (CAF) are a predominant and heterogeneous population of stromal cells within the pancreatic tumor microenvironment. Here, we uncover a previously unrecognized role for hypoxia in driving an inflammatory phenotype in PDAC CAFs. We identify hypoxia as a strong inducer of tumor IL1ɑ expression, which is required for inflammatory CAF (iCAF) formation. Notably, iCAFs preferentially reside in hypoxic regions of PDAC. Our data implicate hypoxia as a critical regulator of CAF heterogeneity in PDAC.

WDR5 drives the development of cervical squamous cell carcinoma by inducing epithelial-mesenchymal transition and cancer-associated fibroblasts formation

BackgroundWD repeat domain 5 (WDR5) has been indicated to be involved in tumor progression, however, its role in cervical cancer (CC) has not been investigated yet. MethodsA total of 350 pairs of CC tissues and para-carcinoma tissues (PCT) were collected. Primary human cervical epithelial cells (hCECs) and cancer-associated fibroblasts (CAFs) were isolated from cervical cancer tissues. MM102 was used to block the interaction between WDR5 and mixed lineage leukemia protein-1 (MLL1), and it was used in vivo to investigate its therapeutic value. ResultsWDR5 was up-regulated in cervical squamous cell carcinoma (CSCC) tissues compared to that in PCT. C-X-C motif chemokine ligand 8 (CXCL8) was indicated to be the target gene of WDR5. Highly expressed CXCL8 promoted epithelial-mesenchymal transition (EMT) to form CAFs, and enhanced the cytokine secretions in CAFs to promote CSCC progression. CXCL8 expression was regulated by the interaction between WDR5 and MLL1, and blocking the interaction between these two proteins using MM102 significantly suppressed tumor growth in mice models. ConclusionsWDR5 plays a key role in CSCC progression by inducing CXCL8 expression and promoting the transformation of CAFs from epithelial cells.

Abstract 3192: EBV-products containing exosomes remodel NPC tumor microenvironment by activating fibroblasts

Abstract Epstein-Barr virus (EBV) infection is intimately associated with type III nasopharyngeal carcinoma (NPC). Most NPCs respond well to chemoradiation. Nevertheless, approximately 20% of patients experience recurrence and distant metastasis. Tumor desmoplastic responses and high densities of cancer-associated fibroblasts (CAFs) within tumors have been correlated with poorer prognosis. In this study, we demonstrate that EBV activates fibroblasts via exosomes to remodel a pro-tumoral microenvironment. Exosomes derived from NPC cells contained a high level of fibroblast activation protein alpha (FAPα) and EBV-encoded latent membrane protein 1 (LMP1). Treating primary fibroblasts with these exosomes induced functional changes resembling CAFs. Transcriptomic analysis on exosome-treated fibroblasts revealed genes involved in fibrosis-associated pathways were enriched. Noticeably, treating with EBV products-containing exosomes in fibroblasts enhanced the production of several immune-suppressive cytokines, including IL6, IL8, and MCP-1. Moreover, stimulation with these exosomes enhanced activation of YAP1 signaling, a key pathway linking to fibrosis. The in vivo mouse xenografted NPC studies showed that EBV products-containing exosomes markedly enhanced the severity of tissue fibrosis and tumor growth. IHC analysis on mouse NPC xenografts and human NPC biopsies showed a positive correlation between levels of nuclear YAP1 and FAPα, which were further correlated with an enhanced fibrotic response within tumors. Pharmaceutical intervention with YAP1 inhibitors blocked the exosome-mediated effects on fibroblasts. Collectively, our data suggest that EBV products-containing exosome is a causal factor in CAF formation, which constitutes a pro-tumoral microenvironment to benefit the survival of both tumor and virus itself. Citation Format: Po-Ju Lee, Yun-Hua Sui, Chen-Han Huang, Tzu-Tung Liu, Ngan-Ming Tsang, Shu-Chen Liu. EBV-products containing exosomes remodel NPC tumor microenvironment by activating fibroblasts [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3192.

Influence of Wound Fluid on the Transdifferentiation of Human Mesenchymal Bone Marrow Stem Cells into Cancer-Associated Fibroblasts

Cancer-associated fibroblasts (CAF) in the tumor microenvironment have a decisive influence on tumor growth and metastatic behavior. The cellular origins as well as the stimuli leading to CAF formation are heterogenous, impeding a precise characterization. Aim of this study was to analyze the influence of cytokines secreted in the process of wound healing, tumor cell-associated paracrine-secreted factors, and direct cell-cell contact on the expression of the CAF-associated markers fibroblast activation protein (FAP), α-smooth muscle actin (α-SMA), thrombospondin-1 (THBS1), and tenascin-c (TNC) by RT-PCR in mesenchymal stem cells (MSC). Cells developed different morphological characteristics after incubation with wound fluid (WF). Moreover, expression of FAP and α-SMA in MSC was significantly reduced after WF compared to tumor-conditioned medium and in co-culture with tumor cells; THBS1 and TNC were not significantly altered after any of the different incubation methods. There were no alterations of expression patterns of FAP and α-SMA in the immunohistochemical analysis. Differ­ences in the cytokine composition of the media were found in the dot blot. The heterogeneity of the results emphasizes the complexity of the interactions of tumor cells and cells of the microenvironment, particularly through the addition of human-derived WF.