Search

The tumor microenvironment (TME) is known to direct cancer cell growth, migration, invasion into the matrix and distant tissues, and to confer drug resistance in cancer cells. While multiple aspects of TME have been studied using in vitro , ex vivo , and in vivo tumor models and engineering tools, the influence of matrix viscoelasticity on pancreatic cancer cells and its associated TME remained largely unexplored. In this contribution, we synthesized a new biomimetic hydrogel with tunable matrix stiffness and stress-relaxation for evaluating the effect of matrix viscoelasticity on pancreatic cancer cell (PCC) behaviors in vitro . Using three simple monomers and Reverse-Addition Fragmentation Chain-Transfer (RAFT) polymerization, we synthesized a new class of phenylboronic acid containing polymers (e.g., poly (OEGA- s -HEAA- s -APBA) or PEHA). Norbornene group was conjugated to HEAA on PEHA via carbic anhydride, affording a new NB and BA dually modified polymer - PEH NB A amenable for orthogonal thiol-norbornene photopolymerization and boronate ester diol complexation. The former provided tunable matrix elasticity, while the latter gave rise to matrix stress-relaxation (or viscoelasticity). The new PEH NB A polymers were shown to be highly cytocompatible for in situ encapsulation of PCCs and cancer-associated fibroblasts (CAFs). Furthermore, we demonstrated that hydrogels with high stress-relaxation promoted spreading of CAFs, which in turns promoted PCC proliferation and spreading in the viscoelastic matrix. Compared with elastic matrix, viscoelastic gels upregulated the secretion of soluble proteins known to promote epithelial-mesenchymal transition (EMT). This study demonstrated the crucial influence of matrix viscoelasticity on pancreatic cancer cell fate and provided an engineered viscoelastic matrix for future studies and applications related to TME., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Chien-Chi Lin reports financial support was provided by 10.13039/100000002National Institutes of Health. Melissa Fishel reports financial support was provided by 10.13039/100000002National Institutes of Health. Chien-Chi Lin has patent pending to Indiana University., (© 2023 The Authors.)

A fundamental step of tumor metastasis is tumor cell migration away from the primary tumor site. One mode of migration that is essential but still understudied is collective invasion, the process by which clusters of cells move in a coordinated fashion. In recent years, there has been growing interest to understand factors regulating collective invasion, with increasing number of studies investigating the biomechanical regulation of collective invasion. In this review we discuss the dynamic relationship between tumor microenvironment cues and cell response by first covering mechanical factors in the microenvironment and second, discussing the mechanosensing pathways utilized by cells in collective clusters to dynamically respond to mechanical matrix cues. Finally, we discuss model systems that have been developed which have increased our understanding of the mechanical factors contributing to tumor progression., (Copyright © 2023. Published by Elsevier Inc.)

Pancreatic ductal adenocarcinoma (PDAC) is one of the foremost causes of cancer-related morbidities worldwide. Novel nanotechnology-backed drug delivery stratagems, including molecular targeting of the chemotherapeutic payload, have been considered. However, no quantum leap in the gross survival rate of patients with PDAC has been realized. One of the predominant causes behind this is tumor desmoplasia, a dense and heterogenous stromal extracellular matrix of the tumor, aptly termed tumor microenvironment (TME). It plays a pivotal role in the tumor pathogenesis of PDAC as it occupies most of the tumor mass, making PDAC one of the most stromal-rich cancers. The complex crosstalk between the tumor and dynamic components of the TME impacts tumor progression and poses a potential barrier to drug delivery. Understanding and deciphering the complex cascade of tumorstromal interactions are the need of the hour so that we can develop neoteric nano-carriers to disrupt the stroma and target the tumor. Nanodiamonds (NDs), due to their unique surface characteristics, have emerged as a promising nano delivery system in various pre-clinical cancer models and have the potential to deliver the chemotherapeutic payload by moving beyond the dynamic tumor-stromal barrier. It can be the next revolution in nanoparticle-mediated pancreatic cancer targeting., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Fibroblast activation protein alpha (FAPα) is a cell surface protease expressed by cancer-associated fibroblasts in the microenvironment of most solid tumors. As there is increasing evidence for proteases having non-catalytic functions, we determined the FAPα interactome in cancer-associated fibroblasts using the quantitative immunoprecipitation combined with knockdown (QUICK) method. Complex formation with adenosin deaminase, erlin-2, stomatin, prohibitin, Thy-1 membrane glycoprotein, and caveolin-1 was further validated by immunoblotting. Co-immunoprecipitation (co-IP) of the known stoichiometric FAPα binding partner dipeptidyl-peptidase IV (DPPIV) corroborated the proteomic strategy. Reverse co-IPs validated the FAPα interaction with caveolin-1, erlin-2, and stomatin while co-IP upon RNA-interference mediated knock-down of DPPIV excluded adenosin deaminase as a direct FAPα interaction partner. Many newly identified FAPα interaction partners localize to lipid rafts, including caveolin-1, a widely-used marker for lipid raft localization. We hypothesized that this indicates a recruitment of FAPα to lipid raft structures. In density gradient centrifugation, FAPα co-fractionates with caveolin-1. Immunofluorescence optical sectioning microscopy of FAPα and lipid raft markers further corroborates recruitment of FAPα to lipid rafts and invadopodia. FAPα is therefore an integral component of stromal lipid rafts in solid tumors. In essence, we provide one of the first interactome analyses of a cell surface protease and translate these results into novel biological aspects of a marker protein for cancer-associated fibroblasts. [ABSTRACT FROM AUTHOR]

Purpose Solid tumors modulate their environment to keep non-malignant stromal cells in a tumor-promoting state. The main cells in the stroma of epithelial derived tumors are cancer associated fibroblasts (CAF) that are critical to tumorigenesis and angiogenesis. CAFs also supply the tumor cells with growth factors and extracellular matrix (ECM) degrading enzymes. They are thus essential for tumor initiation as well as tumor progression and metastasis, suggesting that they represent an ideal cellular target of an integrative tumor therapy. Fibroblast activation protein (FAP) is a well-defined marker, expressed at high levels on the cell surface of CAFs. FAP, a constitutively active serine peptidase with both dipeptidyl peptidase IV (DPP IV) and collagenase/gelatinase activity, promotes malignant and invasive behavior of epithelial cancers. High stromal expression levels of FAP correlate with poor prognosis. FAP is difficult to detect in non-diseased adult tissue, but it is generally expressed at sites of tissue remodeling. Materials and methods In our experiments, we aimed for a reduction of the pro-tumorigenic activities of CAFs by depleting FAP from fibroblasts growing in a composite environment with epithelial tumor cells. Results FAP depletion was achieved by two therapeutically relevant approaches: a novel internalizing anti-FAP IgG1 antibody and FAP gene knock-down by siRNA delivery. The antibody effectively removed FAP from the cell surface and was capable of reversing the FAP mediated migratory and invasive capacity. FAP RNA interference was equally effective when compared to the antibody. Conclusions Thus, targeting FAP on CAF suppresses pro-tumorigenic activities and may result in a clinically effective reduction of tumor progression and dissemination. [ABSTRACT FROM AUTHOR]

Background: Cancer-associated fibroblasts (CAFs) in the stroma are considered to play important roles for gastric cancer proliferation, invasion, and fibrosis, but the source of CAFs and their interaction with cancer cells in the microenvironment have not been fully determined. Here we elucidated the role of bone marrow-derived cells, fibrocytes, in development of gastric cancers, as represented by scirrhous gastric cancer. Materials and methods: In co-culturing MKN45 gastric cancer cells and purified fibrocytes from healthy volunteers, migration and endothelial mesenchymal transition associated gene expression were evaluated using western blot analysis. Also, mouse xenograft models of MKN45 with or without fibrocytes were conducted to investigate their tumorigenicity and immunohistological differences of tumors. Results: Co-culture of fibrocytes with MKN45 resulted in morphological changes from cobblestone-shape to spindle-shape and enhanced expression of α-SMA and collagen type I in fibrocytes, suggesting that co-culture with gastric cancer cells may have induced the differentiation of fibrocytes to myofibroblasts. Furthermore, enhanced expression of SDF-1 in MKN45 and CXCR4 in fibrocytes were also determined. Mouse xenograft models inoculated with MKN45 and fibrocytes revealed significantly larger tumors than those inoculated with MKN45 cells alone, and the stroma in co-inoculated tumors consisted of myofibroblasts and fibrosis. Mouse-derived cells expressing both CD45 and type I collagen were also observed in co-inoculated tumors. Conclusion: Fibrocytes derived from bone marrow may migrate into the microenvironment of gastric cancer by SDF-1/CXCR4 system, and enhance the tumor proliferation and fibrosis as CAFs. [ABSTRACT FROM AUTHOR]

Background: Comparison of tissue microarray results of 29 cervical cancer and 27 normal cervix tissue samples using immunohistochemistry revealed considerable reorganization of the fibrillar stroma of these tumors. Preliminary densitometry analysis of laminin-1, α-smooth muscle actin (SMA) and fibronectin immunostaining demonstrated 3.8-fold upregulation of laminin-1 and 5.2-fold increase of SMA in the interstitial stroma, indicating that these proteins and the activated fibroblasts play important role in the pathogenesis of cervical cancer. In the present work we investigated the role of normal and tumor-associated fibroblasts. Methods: In vitro models were used to throw light on the multifactorial process of tumor-stroma interaction, by means of studying the cooperation between tumor cells and fibroblasts. Fibroblasts from normal cervix and cervical cancers were grown either separately or in co-culture with CSCC7 cervical cancer cell line. Changes manifest in secreted glycoproteins, integrins and matrix metallo-proteases (MMPs) were explored. Results: While normal fibroblasts produced components of interstitial matrix and TGF-β1 that promoted cell proliferation, cancer-associated fibroblasts (CAFs) synthesized ample amounts of laminin-1. The following results support the significance of laminin-1 in the invasion of CSCC7 cells: 1.) Tumor-associated fibroblasts produced more laminin-1 and less components of fibrillar ECM than normal cells; 2.) The production of laminin chains was further increased when CSCC7 cells were grown in co-culture with fibroblasts; 3.) CSCC7 cells were capable of increasing their laminin production; 4.) Tumor cells predominantly expressed integrin α6β4 laminin receptors and migrated towards laminin. The integrin profile of both normal and tumor-associated fibroblasts was similar, expressing receptors for fibronectin, vitronectin and osteopontin. MMP-7 secreted by CSCC7 cells was upregulated by the presence of normal fibroblasts, whereas MMP-2 produced mainly by fibroblasts was activated in the presence of CSCC7 cells. Conclusions: Our results indicate that in addition to degradation of the basement membrane, invasion of cervical cancer is accomplished by the remodeling of the interstitial stroma, which process includes decrease and partial replacement of fibronectin and collagens by a laminin-rich matrix. [ABSTRACT FROM AUTHOR]

Objective Local invasion is a common pattern of spread in uterine cervical squamous cell carcinoma (CSCC). Although transforming growth factor-beta (TGF-β) facilitates invasion of various types of cancer cells, the role of the TGF-β pathway in CSCC is unclear. In this study, we analyzed the role of TGF-β signaling in the progression of CSCC. Methods Immunohistochemistry was used to examine the expression of TGF-β pathway molecules in 67 CSCC samples with clinicopathological data. Activation of the TGF-β pathway was investigated following co-culture of CSCC cells and cervical cancer-associated fibroblasts (CCAFs). Results Clinicopathological analysis of CSCC samples revealed that prominent expression of TGF-β receptor-2 was more frequent in CSCC with lymphovascular space invasion (LVSI) than without LVSI (p < 0.01). Lymph node metastasis was more frequent in cases in which phosphorylated SMAD3 (pSMAD3) was localized exclusively at the boundary of tumor clusters (n = 9, p < 0.05). Recombinant TGF-β1 increased pSMAD3 expression and enhanced cellular invasion (p < 0.005) in CSCC cells, which was attenuated by an inhibitor of the TGF-β receptor (p < 0.005). Enhanced pSMAD3 expression and invasion was also observed when conditioned media from CSCC cells co-cultured with CCAFs were administered. Luciferase assays showed that this medium contained a large amount of active TGF-β. Along with TGF-β activation, thrombospondin-1 was upregulated in both CSCC cells and CCAFs, while thrombospondin-1 silencing in either CSCC cells or CCAFs repressed the activity of TGF-β. Thrombospondin-1 was prominently expressed in cases with pSMAD3 boundary staining (p < 0.05). Conclusions These results suggest that interaction between CSCC cells and surrounding CCAFs activates TGF-β via thrombospondin-1 secretion to facilitate CSCC invasion. [ABSTRACT FROM AUTHOR]

Although the prognosis for acute leukemia has greatly improved, treatment of relapsed/refractory acute leukemia (R/R AL) remains challenging. Recently, increasing evidence indicates that the bone marrow microenvironment (BMM) plays a crucial role in leukemogenesis and therapeutic resistance; therefore, BMM-targeted strategies should be a potent protocol for treating R/R AL. The targeting of cancer-associated fibroblasts (CAFs) in solid tumors has received much attention and has achieved some progress, as CAFs might act as an organizer in the tumor microenvironment. Additionally, over the last 10 years, attention has been drawn to the role of CAFs in the BMM. In spite of certain successes in preclinical and clinical studies, the heterogeneity and plasticity of CAFs mean targeting them is a big challenge. Herein, we review the heterogeneity and roles of CAFs in the BMM and highlight the challenges and opportunities associated with acute leukemia therapies that involve the targeting of CAFs., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Gu, Liao and Liu.)

Introduction: Pancreatic ductal adenocarcinoma (PDAC) is characterized by abundant stroma and cancer-associated fibroblasts (CAFs) provide a favorable tumor microenvironment. Smad4 is known as tumor suppressor in several types of cancers including PDAC, and loss of Smad4 triggers accelerated cell invasiveness and metastatic potential. The thrombospondin-1 (TSP-1) can act as a major activator of latent transforming growth factor-β (TGF-β) in vivo. However, the roles of TSP-1 and the mediator of Smad4 loss and TGF-β signal activation during PDAC progression have not yet been addressed. The aim is to elucidate the biological role of TSP-1 in PDAC progression., Methods and Results: High substrate stiffness stimulated TSP-1 expression in CAFs, and TSP-1 knockdown inhibited cell proliferation with suppressed profibrogenic and activated stroma-related gene expressions in CAFs. Paracrine TSP-1 treatment for PDAC cells promoted cell proliferation and epithelial mesenchymal transition (EMT) with activated TGF-β signals such as phosphorylated Akt and Smad2/3 expressions. Surprisingly, knockdown of DPC4 (Smad4 gene) induced TSP-1 overexpression with TGF-β signal activation in PDAC cells. Interestingly, TSP-1 overexpression also induced downregulation of Smad4 expression and enhanced cell proliferation in vitro and in vivo. Treatment with LSKL peptide, which antagonizes TSP-1-mediated latent TGF-β activation, attenuated cell proliferation, migration and chemoresistance with enhanced apoptosis in PDAC cells., Conclusions: TSP-1 derived from CAFs stimulates loss of Smad4 expression in cancer cells and accelerates malignant behavior by TGF-β signal activation in PDAC. TSP-1 could be a novel therapeutic target, not only for CAFs in stiff stroma, but also for cancer cells in the PDAC microenvironment., Competing Interests: Declaration of Competing Interest No conflicts of interest, financial or otherwise, have been declared by the authors., (Copyright © 2022. Published by Elsevier Inc.)

Background The "seed and soil" hypothesis emphasizes the importance of interactions between tumor cells and their microenvironment. CAFs (Cancer associated fibroblasts) are important components of the tumor microenvironment. They were widely involved in cancer cells growth and metastasis. Fibroblasts may also play a role in inflammatory disease. The phenotype conversion of fibroblasts in lung diseases has not been investigated previously. We hypothesized that fibroblasts phenotypes may vary among different types of lung disease. Methods The study included six types of lung tissues, ranging from normal lung to lung adenocarcinoma with lymphatic metastasis. Para-carcinoma tissues which were 2-cm-away from the tumor focus were also included in the analysis. The expression of target proteins including alpha-SMA (smooth muscle actin), FAP (fibroblast activation protein), vimentin, E-cadherin, and CK-19 (cytokeratin-19) were examined by immunohistochemistry. TGFbeta( transforming growth factor) and Twist were detected simultaneously in all samples. Results A progressive increase in the levels of alpha-SMA, vimentin and CK-19 was observed in correlation to the degree of malignancy from normal lung tissue to lung adenocarcinoma with lymphatic metastasis, whereas E-cadherin expression showed the opposite trend. TGF-beta and Twist were detected in cancer tissues and inflammatory pseudotumors. None of the proteins were detected in para-carcinoma tissues. Conclusions Fibroblast phenotypes varied according to the type and degree of lung malignancy and fibroblasts phenotypic conversion occurs as a gradual process with specific spatiotemporal characteristics. Similar fibroblast phenotypes in inflammatory diseases and cancer tissues suggested a correlation between inflammation and cancer and implied a common mechanism underlying the formation of fibroblasts in inflammatory diseases and lung cancer. [ABSTRACT FROM AUTHOR]

Cancer associated fibroblasts (CAFs) comprise a heterogeneous population that resides within the tumor microenvironment. They actively participate in tumor growth and metastasis by production of cytokines and chemokines, and the release of pro-inflammatory and pro-angiogenic factors, creating a more supportive microenvironment. The aim of the current review is to summarize the origin and characteristics of CAFs, and to describe the role of CAFs in tumor progression and metastasis. Furthermore, we focus on the presence of CAFs in hypoxic conditions in relation to multiple myeloma disease. [ABSTRACT FROM AUTHOR]

Highlights: [•] MiR-106b is up-regulated in CAFs compared to NFs in gastric cancer. [•] Down-regulation of miR-106b in CAFs inhibits cancer cell motility by targeting PTEN. [•] MiR-106b might be a potential therapeutic target for gastric cancer. [Copyright &y& Elsevier]

Background In a malignant tumour, cancer cells are embedded in stromal cells, namely cancer-associated fibroblasts (CAFs). These CAFs are now accepted as important players in cancer dynamics, being involved in tumour growth and progression. Although there are various reports on the interaction between tumour and stromal cells, the clinico-pathological significance of this cross-talk is still largely unknown. In this study, we aimed to characterise the expression of key metabolic proteins involved in glucose transport, pyruvate/lactate shuttle system, glycolytic metabolism and fatty acid oxidation in CAFs and tumour cells in different stages of malignant transformation. We further aimed to contextualise the clinico-pathological significance of these protein expression profiles with reference to known prognostic indicators, including biochemical recurrence in pT stage. Methods Prostate tissues were obtained from 480 patients with a median age of 64 years following radical prostatectomy with no previous hormonal therapy. Tissues were analysed for the expression of several key metabolism-related proteins in glands and surrounding fibroblasts by immunohistochemistry. Reliable markers of prognosis such as pT stage and biochemical recurrence were assessed for each case. Results We observed that prostate cancer cells did not rely mainly on glycolytic metabolism, while there was a high expression of MCT4 and CAIX - in CAFs. This corroborates the hypothesis of the "Reverse Warburg effect" in prostate cancer, in which fibroblasts are under oxidative stress and express CAIX, an established hypoxia marker. We found that alterations in the expression of metabolism-related proteins were already evident in the early stages of malignant transformation, suggesting the continuing alteration of CAFs from an early stage. Additionally, and for the first time, we show that cases showing high MCT4 expression in CAFs with concomitant strong MCT1 expression in prostate cancer (PCa) cells are associated with poor clinical outcome, namely pT3 stage of the tumour. Conclusions In summary, this work demonstrates for the first time the clinico-pathological significance of the lactate shuttle in prostate cancer. It also suggests that other alterations in CAFs may be useful prognostic factors, and further supports the use of MCT1/MCT4 as targets for PCa therapy. [ABSTRACT FROM AUTHOR]

Tumors are not merely masses of neoplastic cells but complex tissues composed of cellular and noncellular elements. This review provides recent data on the main components of a dynamic system, such as carcinoma associated fibroblasts that change the extracellular matrix (ECM) topology, induce stemness and promote metastasis-initiating cells. Altered production and characteristics of collagen, hyaluronan and other ECM proteins induce increased matrix stiffness. Stiffness along with tumor growth-induced solid stress and increased interstitial fluid pressure contribute to tumor progression and therapy resistance. Second, the role of immune cells, cytokines and chemokines is outlined. We discuss other noncellular characteristics of the tumor microenvironment such as hypoxia and extracellular pH in relation to neoangiogenesis. Overall, full understanding of the events driving the interactions between tumor cells and their environment is of crucial importance in overcoming treatment resistance and improving patient outcome. [ABSTRACT FROM AUTHOR]

Abstract: The microenvironment of established tumours is often immunosuppressed, and this allows tumours to grow and disseminate without being eliminated by the patient's immune system. The recent FDA approval of immunotherapies such as ipilimumab and sipuleucel-T that directly activate the adaptive and innate immune responses has triggered interest in developing other novel anti-cancer approaches that modulate the immune system. Understanding how the different constituents of the tumour microenvironment influence the immune system is thus crucial and is expected to generate a plethora of factors that can be targeted to boost immunity and trigger long lasting anti-tumour efficacy. Cancer associated fibroblasts (CAFs) are a crucial component of the tumour microenvironment. Through secretion of multiple growth factors, cytokines and proteases, CAFs are known to be key effectors for tumour progression and can promote cancer cell growth, invasiveness and angiogenesis. However, recent publications have also linked CAF biology to innate and adaptive immune cell recruitment and regulation. Here, we review recent findings on how CAFs can influence the immune status of tumours through direct and indirect interaction with immune cells and other key components of the tumour microenvironment. [Copyright &y& Elsevier]

Background: Cancer cell adopts peculiar metabolic strategies aimed to sustain the continuous proliferation in an environment characterized by relevant fluctuations in oxygen and nutrient levels. Monocarboxylate transporters MCT1 and MCT4 can drive such adaptation permitting the transport across plasma membrane of different monocarboxylic acids involved in energy metabolism. Methods: Role of MCTs in tumor-stroma metabolic relationship was investigated in vitro and in vivo using transformed prostate epithelial cells, carcinoma cell lines and normal fibroblasts. Moreover prostate tissues from carcinoma and benign hypertrophy cases were analyzed for individuating clinical-pathological implications of MCT1 and MCT4 expression. Results: Transformed prostate epithelial (TPE) and prostate cancer (PCa) cells express both MCT1 and MCT4 and demonstrated variable dependence on aerobic glycolysis for maintaining their proliferative rate. In glucose-restriction the presence of L-lactate determined, after 24 h of treatment, in PCa cells the up-regulation of MCT1 and of cytochrome c oxidase subunit I (COX1), and reduced the activation of AMP-activated protein kinase respect to untreated cells. The blockade of MCT1 function, performed by si RNA silencing, determined an appreciable antiproliferative effect when L-lactate was utilized as energetic fuel. Accordingly L-lactate released by high glycolytic human diploid fibroblasts WI-38 sustained survival and growth of TPE and PCa cells in low glucose culture medium. In parallel, the treatment with conditioned medium from PCa cells was sufficient to induce glycolytic metabolism in WI-38 cells, with upregulation of HIF-1a and MCT4. Co-injection of PCa cells with high glycolytic WI-38 fibroblasts determined an impressive increase in tumor growth rate in a xenograft model that was abrogated by MCT1 silencing in PCa cells. The possible interplay based on L-lactate shuttle between tumor and stroma was confirmed also in human PCa tissue where we observed a positive correlation between stromal MCT4 and tumor MCT1 expression. Conclusions: Our data demonstrated that PCa progression may benefit of MCT1 expression in tumor cells and of MCT4 in tumor-associated stromal cells. Therefore, MCTs may result promising therapeutic targets in different phases of neoplastic transformation according to a strategy aimed to contrast the energy metabolic adaptation of PCa cells to stressful environments. [ABSTRACT FROM AUTHOR]

Abstract: Cancer cells rely on extensive support from the stroma in order to survive, proliferate and invade. The tumor stroma is thus an important potential target for anti-cancer therapy. Typical changes in the stroma include a shift from the quiescence promoting-antiangiogenic extracellular matrix to a provisional matrix that promotes invasion and angiogenesis. These changes in the extracellular matrix are induced by changes in the secretion of extracellular matrix proteins and glucose amino glycans, extravasation of plasma proteins from hyperpermeable vessels and release of matrix modifying enzymes resulting in cleavage and cross-linking of matrix macromolecules. These in turn alter the rigidity of the matrix and the exposure and release of cytokines. Changes in matrix rigidity and vessel permeability affect drug delivery and mediate resistance to cytotoxic therapy. These stroma changes are brought about not only by the cancer cells, but also through the action of many cell types that are recruited by tumors including immune cells, fibroblasts and endothelial cells. Within the tumor, these normal host cells are activated resulting in loss of inhibitory and induction of cancer promoting activities. Key to the development of stroma-targeted therapies, selective biomarkers were developed for specific imaging of key aspects of the tumor stroma. [Copyright &y& Elsevier]

Bortezomib is a proteasome inhibitor active in classical Hodgkin lymphoma (cHL) cell lines, but poorly active in the clinic when used as a single agent, suggesting that the microenvironment could protect from drug efficacy. Therefore, we investigated the effects of bortezomib activity in the presence of HL-associated fibroblasts (HL-AFs) and sCD40L. We found that co-cultivation with human HL-AFs or the addition of sCD40L during bortezomib treatment protected cHL cells from apoptosis and cytotoxicity and rescued the down-regulation of the survival factor interferon regulatory factor 4 (IRF4). In contrast, bortezomib treatment before co-cultivation with HL-AFs inhibited in a dose-dependent manner cHL cell adhesion to HL-AFs and completely overcame HL-AF protection against drug activity. Consistently, we found that bortezomib treatment down-regulated the surface expression of CD49d and CD44, which mediate the adhesion of cHL cells to HL-AFs, and of CD54 and CD40, which mediate the adhesion to CD40L+ rosetting T-cells. These preclinical findings suggest that the low in vivo activity of bortezomib as a single agent may be due to a protective influence of the microenvironment. However, inclusion of bortezomib in the cHL drug regimen, by reducing IRF4 expression and interactions with the microenvironment, could increase the efficacy of current chemotherapeutic treatment of relapsed/refractory cHL. [ABSTRACT FROM AUTHOR]

A bstract Cells constituting the tumor microenvironment are attractive targets for developing new cancer therapies. Here we show that cancer-associated fibroblasts (CAFs) support tumor growth in vivo and maintain the stemness of cancer stem/initiating cells in an in vitro model using an established CAF cell line. We found that CD44 is abundantly expressed on CAFs. This molecule is a cancer stem cell marker in several tumors, but its role in tumorigenesis when expressed by CAFs has not been investigated. It is generally accepted that hypoxic and hyponutritional conditions are triggers of cancer malignancy. We found that CAFs strongly express CD44 in hypoxic and avascular areas in the tumor and that its expression on established CAFs is upregulated under hypoxic and hyponutritional conditions in vitro. In addition, CAF CD44-positivity in tumor tissues was increased after treatment with inhibitors of angiogenesis. Using cocultures and tumor sphere formation assays, CAFs from wild-type mice were found to sustain the stemness of cancer stem/initiating cells, while CD44-deficient CAFs did not. Furthermore, CD44 was involved in malignant cancer cell drug resistance mechanisms. In conclusion, our study suggests that CD44 on CAFs is a functional molecule contributing to the maintenance of cancer stem cell populations in the tumor microenvironment. S tem C ells 2014;32:145-156 [ABSTRACT FROM AUTHOR]

Pancreatic ductal adenocarcinoma (PDAC) is a highly fatal malignancy with extremely poor prognosis. Gemcitabine resistance is a major challenge in the treatment of PDAC. Here, we showed that LINC00460 was associated with the response to gemcitabine both in PDAC patients and PDAC-PDX. After knocking down LINC00460 in PDAC tumor cells, results of RNA sequencing followed by gene ontology analysis indicated that LINC00460 influenced the activity of growth factors and modified the extracellular matrix. FISH showed that LINC00460 is mostly located in the cytoplasm. Results of RNA pull-down, LC-MS/MS, RIP, and immunoblotting confirmed that LINC00460 could directly bind to PDAP1. Furthermore, we demonstrated that LINC00460 mediated the cellular communication of PDAC tumor cells and CAFs by PDAP1/PDGFA/PDGFR signaling pathway and regulated the gemcitabine-resistance function of CAFs, which could be reversed by treatment with a PDGFR inhibitor (crenolanib). PDAC-PDX tumors with lower expression of LINC00460 showed a better response to gemcitabine plus crenolanib treatment. Our finding supported the application of LINC00460 in precision medicine that uses gemcitabine plus crenolanib to treat PDAC with low expression of LINC00460., (© 2022 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)

Systemic treatments (e.g., chemotherapy and targeted therapies) have limited efficacy for patients with locally advanced - unresectable - and metastatic cholangiocarcinoma (CCA), with an overall survival of less than a year. Tumor microenvironment (TME) represents the ecosystem surrounding the tumor which comprises immune cells, fibroblasts, endothelial cells, and a wide range of soluble factors. CCA TME is characterized by an abundant desmoplastic stroma, exhibits a high heterogeneity and it plays a central role in cancer onset and progression. There is growing evidence suggesting that it is possible to target TME in association with other treatment modalities, such as cytotoxic chemotherapy or targeted therapies, paving the way to possible combination strategies with a synergistic effect. Herein, we describe the components of CCA TME - such as cancer-associated fibroblasts and other cells of pivotal importance - with their most relevant interactions, focusing on the preclinical rationale for the development of effective anticancer treatments., Competing Interests: Declaration of Competing Interest All authors declared that there are no conflicts of interest., (Copyright © 2022. Published by Elsevier Inc.)

Clear cell renal cell carcinoma (ccRCC) is globally the most prevalent renal cancer. The cells of origin in ccRCC have been identified as proximal tubular epithelial cells (PTEC); however, the transcriptomic pathways resulting in the transition from normal to malignant PTEC state have remained unclear. Immunotherapy targeting checkpoints have revolutionized the management of ccRCC, but a sustained clinical response is achieved in only a minority of ccRCC patients. This indicates that our understanding of the mechanisms involved in the malignant transition and resistance to immune checkpoint therapy in ccRCC is unclear. This review examines recent single-cell transcriptomics studies of ccRCC to clarify the transition of PTEC in ccRCC development, and the immune cell types, states, and interactions that may limit the response to targeted immune therapy, and finally suggests stromal cells as key drivers in recurrent and locally invasive ccRCC. These and future single-cell transcriptomics studies will continue to clarify the cellular milieu in the ccRCC microenvironment, thus defining actional clinical, therapeutic, and prognostic characteristics of ccRCC., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Raghubar, Roberts, Wood, Healy, Kassianos and Mallett.)

Extracellular matrix (ECM) critically regulates cancer cell behavior by governing cell signaling and properties. Hyaluronan (HA) acts as a structural and functional ECM component that mediates critical properties of cancer cells in a molecular size-dependent manner. HA fragments secreted by cancer-associated fibroblasts (CAFs) reveal the correlation of HA to CAF-mediated matrix remodeling, a key step for the initiation of metastasis. The main goal of this article is to highlight the vital functions of HA in cancer cell initiation and progression as well as HA-mediated paracrine interactions among cancer and stromal cells. Furthermore, the HA implication in mediating immune responses to cancer progression is also discussed. Novel data on the role of HA in the formation of pre-metastatic niche may contribute towards the improvement of current theranostic approaches that benefit cancer management., (© 2022 International Union of Biochemistry and Molecular Biology.)

Background: Increasing evidence has revealed an important role of versican (VCAN) on various aspects of cancer progression. Here, we assessed the impact of VCAN expression on prognosis and the response to adjuvant therapy and immunotherapy in patients with gastric cancer (GC)., Methods: Four independent cohorts containing 1353 patients with GC, were utilized to investigate the effect of VCAN expression on prognosis and response to adjuvant therapy in GC. Two cohorts treated with immune checkpoint blockades were included to assess the predict value of VCAN expression on response to immunotherapy. Moreover, the bulk RNA-seq and single-cell RNA-seq data were analyzed to illustrate the role of VCAN in tumor microenvironment. Clinical outcomes of patient subgroups were compared by Kaplan-Meier curves with the log-rank test., Result: High VCAN expression was associated with poor prognosis for patients with GC. Compared with patients with high VCAN expression, patients with low VCAN expression benefited more from adjuvant chemotherapy and adjuvant chemoradiotherapy. Moreover, patients with high VCAN expression tended to be resistant to immunotherapy, and VCAN could serve as a promising indicator for predicting the response to immunotherapy. VCAN high tumors showed a specific microenvironment with more cancer associated fibroblasts infiltration and significant enrichment of stromal relevant signaling pathways., Conclusion: VCAN could predict the response to adjuvant chemotherapy, adjuvant chemoradiotherapy and immunotherapy in GC, and designing new medicine target to VCAN might be an effective way to improve the efficacy of several treatment options for GC., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Song, Wei, Huo, Liu and Liu.)

Background: Partial/complete pathologic response following neoadjuvant chemotherapy (NAC) in pancreatic cancer (PDAC) patients undergoing pancreatectomy is associated with improved survival. We sought to determine whether neutrophil-to-lymphocyte ratio (NLR) dynamics predict pathologic response following chemotherapy in PDAC, and if manipulating NLR impacts chemosensitivity in preclinical models and uncovers potential mechanistic underpinnings underlying these effects., Methods: Pathologic response in PDAC patients (n=94) undergoing NAC and pancreatectomy (7/2015-12/2019) was dichotomized as partial/complete or poor/absent. Bootstrap-validated multivariable models assessed associations between pre-chemotherapy NLR (%neutrophils÷%lymphocytes) or NLR dynamics during chemotherapy (ΔNLR = pre-surgery-pre-chemotherapy NLR) and pathologic response, disease-free survival (DFS), and overall survival (OS). To preclinically model effects of NLR attenuation on chemosensitivity, Ptf1a Cre/+ ; Kras LSL-G12D/+ ;Tgfbr2 flox/flox (PKT) mice and C57BL/6 mice orthotopically injected with Kras LSL-G12D/+ ;Trp53 LSL-R172H/+ ;Pdx1 Cre (KPC) cells were randomized to vehicle, gemcitabine/paclitaxel alone, and NLR-attenuating anti-Ly6G with/without gemcitabine/paclitaxel treatment., Results: In 94 PDAC patients undergoing NAC (median:4 months), pre-chemotherapy NLR (p<0.001) and ΔNLR attenuation during NAC (p=0.002) were independently associated with partial/complete pathologic response. An NLR score = pre-chemotherapy NLR+ΔNLR correlated with DFS (p=0.006) and OS (p=0.002). Upon preclinical modeling, combining NLR-attenuating anti-Ly6G treatment with gemcitabine/paclitaxel-compared with gemcitabine/paclitaxel or anti-Ly6G alone-not only significantly reduced tumor burden and metastatic outgrowth, but also augmented tumor-infiltrating CD107a + -degranulating CD8 + T-cells (p<0.01) while dampening inflammatory cancer-associated fibroblast (CAF) polarization (p=0.006) and chemoresistant IL-6/STAT-3 signaling in vivo. Neutrophil-derived IL-1β emerged as a novel mediator of stromal inflammation, inducing inflammatory CAF polarization and CAF-tumor cell IL-6/STAT-3 signaling in ex vivo co-cultures., Conclusions: Therapeutic strategies to mitigate neutrophil-CAF-tumor cell IL-1β/IL-6/STAT-3 signaling during NAC may improve pathologic responses and/or survival in PDAC., Funding: Supported by KL2 career development grant by Miami CTSI under NIH Award UL1TR002736, Stanley Glaser Foundation, American College of Surgeons Franklin Martin Career Development Award, and Association for Academic Surgery Joel J. Roslyn Faculty Award (to J. Datta); NIH R01 CA161976 (to N.B. Merchant); and NCI/NIH Award P30CA240139 (to J. Datta and N.B. Merchant)., Competing Interests: Id, AB, ND, PS, SM, VG, SS, JE, PH, DK, NM, JD No competing interests declared, (© 2022, de Castro Silva et al.)

Cancer-associated fibroblasts are a highly heterogeneous group of cells whose phenotypes and gene alterations are still under deep investigation. As a part of tumor microenvironment, they are the focus of a growing number of studies. Cancer-associated fibroblasts might become a new target of breast cancer therapy, but still more tests and analyses are needed to understand mechanisms and interactions between them and breast cancer cells. The study aimed to isolate cancer associated fibroblasts from breast cancer tissue and to phenotype the isolated cell lines. We focused on various cancer-associated fibroblast characteristic biomarkers and those that might differentiate various cancer-associated fibroblasts' subtypes. Patients with a histological diagnosis of invasive breast cancer (diameter ≤15 mm) and qualified for primary surgical treatment were enrolled in the study. Cell lines were isolated from breast cancer biopsy. For the phenotyping, we used flow cytometry, immunofluorescence and RT-qPCR analysis. Based on our study, there was no indication of a clear pattern in the cancer-associated fibroblasts' classification. Results of cancer-associated fibroblasts expression were highly heterogeneous, and specific subtypes were not defined. Moreover, comparing cancer-associated fibroblasts divided into groups based on BC subtypes from which they were isolated also did not allow to notice of any clear pattern of expressions. In the future, a higher number of analyzed cancer-associated fibroblast cell lines should be investigated to find expression schemes., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (AJCR Copyright © 2022.)

Solid tumors are composed of both cancer cells and various types of accessory cells, mainly fibroblasts, that collectively compose the so called tumor-microenvironment. Cancerassociated fibroblasts have been described to actively participate in cancer progression by establishing a cytokine-mediated as well as metabolic crosstalk with cancer cells. In the present paper we show that activated human fibroblasts are able to boost tumor cells proliferation and that this effect is greatly dependent on stromal carbonic anhydrase IX (CA IX) activity. In fact fibroblasts show a strong upregulation of CA IX expression upon activation by cancer cells, while CA IX products, protons and bicarbonate, exert differential effects on cancer cells proliferation. While acidification of extracellular pH, a typical condition of rapidly growing solid tumors, is detrimental for tumor cells proliferation, bicarbonate, through its organication, supplies cancer cells with intermediates useful to sustain their high proliferation rate. Here we propose a new kind of fibroblasts/tumor cells crosstalk within tumor microenvironment, mediated by stromal CA IX products, aimed to favor cancer cells growth, opening new perspectives on CA IX role in tumor microenvironment. [ABSTRACT FROM AUTHOR]

Increasing evidence indicates the importance of the tumor microenvironment, in particular cancer-associated fibroblasts, in cancer development and progression. In our study, we developed a novel, visually based method to identify new immunohistochemical signatures of these fibroblasts. The method employed a protein list based on 759 protein products of genes identified by RNA profiling from our previous study, comparing fibroblasts with differential growth-modulating effect on human cancers cells, and their first neighbors in the human protein interactome. These 2,654 proteins were analyzed in the Human Protein Atlas online database by comparing their immunohistochemical expression patterns in normal versus tumor-associated fibroblasts. Twelve new proteins differentially expressed in cancer-associated fibroblasts were identified (DLG1, BHLHE40, ROCK2, RAB31, AZI2, PKM2, ARHGAP31, ARHGAP26, ITCH, EGLN1, RNF19A and PLOD2), four of them can be connected to the Rho kinase signaling pathway. They were further analyzed in several additional tumor stromata and revealed that the majority showed congruence among the different tumors. Many of them were also positive in normal myofibroblast-like cells. The new signatures can be useful in immunohistochemical analysis of different tumor stromata and may also give us an insight into the pathways activated in them in their true in vivo context. The method itself could be used for other similar analysis to identify proteins expressed in other cell types in tumors and their surrounding microenvironment. [ABSTRACT FROM AUTHOR]

Overexpression of the mucin-type sialoglycoprotein podoplanin in cancer associated fibroblasts (CAFs) was recently shown to be associated with tumor progression, metastasis and poor prognosis in lung and breast cancer. Here we investigate the role of podoplanin expressing CAFs in esophagal adenocarcinoma (AC), its precursor lesions and metastases. Podoplanin expression was investigated immunohistochemically in 200 formalin-fixed, paraffin embedded specimens of invasive esophagal ACs, their corresponding metastases and 35 precursor lesions. Podoplanin expressing CAFs (CAF+) were observed in 22 % of patients with invasive AC, but not in precursor lesions. CAF+ correlated with tumor stage ( p = 0.004), lymphovascular tumor invasion ( p = 0.018) and lymph node metastasis ( p = 0.0016). Patients with CAF+ had a significant shorter disease free and overall survival ( p < 0.05, Cox regression). Podoplanin expressing CAFs were only rarely observed in lymph node and distant metastases, as well as in local recurrences of ACs. Podoplanin expression in AC tumor cells was seen in only four cases. In around 20 % of patients with esophagal AC, podoplanin expressing CAFs are evident, defining a high risk subgroup. In these patients, podoplanin expressing CAFs might represent new therapeutical targets. [ABSTRACT FROM AUTHOR]

Rationale: Osteosarcoma (OS) is the most common primary bone tumor with a poor prognosis, but the detailed mechanism is still unclear. A comprehensive investigation of tumor microenvironment (TME) of OS might help find effective anti-tumor strategies. Single-cell transcriptomics is a powerful new tool to explore TME. Therefore, this study is designed to investigate the TME and gene expression pattern of primary and recurrent OS at the single-cell level. Methods: The single-cell RNA sequencing and bioinformatic analysis were conducted to investigate the cellular constitution of primary, recurrent, and lung metastatic OS lesions according to the datasets of GSE152048 and GSE162454. TIMER database was used to investigate the role of LOX in the prognosis of sarcoma. The functions of related cells and markers were further confirmed by in vitro and in vivo experiments. Results: Cancer associated fibroblasts (CAFs) were found with a higher infiltrating level in recurrent OS, and were enriched in the epithelial-mesenchymal transition (EMT) pathway. CAFs showed remarkably increased expression of LOX, which might lead to EMT and poor prognosis of OS. Mechanically, LOX regulated the function of CAFs and macrophage polarization to remodel the tumor immune microenvironment. Moreover, LOX inhibitor could inhibit migration and promote apoptosis of OS both in vitro and in vivo . Conclusions: This study revealed the heterogeneity of recurrent OS and highlighted an innovative mechanism that CAFs regulate EMT of OS via LOX. Targeting LOX of CAFs showed promising efficacy in remodeling TME and treating recurrent OS., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)