TGFß-Responsive Stromal Activation Occurs Early in Serrated Colorectal Carcinogenesis.

Activated TGFß signaling in the tumor microenvironment, which occurs independently of epithelial cancer cells, has emerged as a key driver of tumor progression in late-stage colorectal cancer (CRC). This study aimed to elucidate the contribution of TGFß-activated stroma to serrated carcinogenesis, representing approximately 25% of CRCs and often characterized by oncogenic BRAF mutations. We used a transcriptional signature developed based on TGFß-responsive, stroma-specific genes to infer TGFß-dependent stromal activation and conducted in silico analyses in 3 single-cell RNA-seq datasets from a total of 39 CRC samples and 12 bulk transcriptomic datasets consisting of 2014 CRC and 416 precursor samples, of which 33 were serrated lesions. Single-cell analyses validated that the signature was expressed specifically by stromal cells, effectively excluding transcriptional signals derived from epithelial cells. We found that the signature was upregulated during malignant transformation and cancer progression, and it was particularly enriched in CRCs with mutant BRAF compared to wild-type counterparts. Furthermore, across four independent precursor datasets, serrated lesions exhibited significantly higher levels of TGFß-responsive stromal activation compared to conventional adenomas. This large-scale analysis suggests that TGFß-dependent stromal activation occurs early in serrated carcinogenesis. Our study provides novel insights into the molecular mechanisms underlying CRC development via the serrated pathway.

Epithelial cells derived exosomal miR-203a-3p facilitates stromal inflammation of type IIIA chronic prostatitis/chronic pelvic pain syndrome by targeting DUSP5 and increasing MCP-1 generation.

Increased proinflammatory cytokines and infiltration of inflammatory cells in the stroma are important pathological features of type IIIA chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS-A), and the interaction between stromal cells and other cells in the inflammatory microenvironment is closely related to the inflammatory process of CP/CPPS-A. However, the interaction between stromal and epithelial cells remains unclear. In this study, inflammatory prostate epithelial cells (PECs) released miR-203a-3p-rich exosomes and facilitated prostate stromal cells (PSCs) inflammation by upregulating MCP-1 expression. Mechanistically, DUSP5 was identified as a novel target gene of miR-203a-3p and regulated PSCs inflammation through the ERK1/2/MCP-1 signaling pathway. Meanwhile, the effect of exosomes derived from prostatic fluids of CP/CPPS-A patients was consistent with that of exosomes derived from inflammatory PECs. Importantly, we demonstrated that miR-203a-3p antagomirs-loaded exosomes derived from PECs targeted the prostate and alleviated prostatitis by inhibiting the DUSP5-ERK1/2 pathway. Collectively, our findings provide new insights into underlying the interaction between PECs and PSCs in CP/CPPS-A, providing a promising therapeutic strategy for CP/CPPS-A.

Cancer-stromal cell interactions in breast cancer brain metastases induce glycocalyx-mediated resistance to HER2-targeting therapies.

Brain metastatic breast cancer is particularly lethal largely due to therapeutic resistance. Almost half of the patients with metastatic HER2-positive breast cancer develop brain metastases, representing a major clinical challenge. We previously described that cancer-associated fibroblasts are an important source of resistance in primary tumors. Here, we report that breast cancer brain metastasis stromal cell interactions in 3D cocultures induce therapeutic resistance to HER2-targeting agents, particularly to the small molecule inhibitor of HER2/EGFR neratinib. We investigated the underlying mechanisms using a synthetic Notch reporter system enabling the sorting of cancer cells that directly interact with stromal cells. We identified mucins and bulky glycoprotein synthesis as top-up-regulated genes and pathways by comparing the gene expression and chromatin profiles of stroma-contact and no-contact cancer cells before and after neratinib treatment. Glycoprotein gene signatures were also enriched in human brain metastases compared to primary tumors. We confirmed increased glycocalyx surrounding cocultures by immunofluorescence and showed that mucinase treatment increased sensitivity to neratinib by enabling a more efficient inhibition of EGFR/HER2 signaling in cancer cells. Overexpression of truncated MUC1 lacking the intracellular domain as a model of increased glycocalyx-induced resistance to neratinib both in cell culture and in experimental brain metastases in immunodeficient mice. Our results highlight the importance of glycoproteins as a resistance mechanism to HER2-targeting therapies in breast cancer brain metastases.

Aberrant activation of TGF-ß/ROCK1 enhances stemness during prostatic stromal hyperplasia.

Benign prostatic hyperplasia (BPH) is a multifactorial disease in which abnormal growth factor activation and embryonic reawakening are considered important factors. Here we demonstrated that the aberrant activation of transforming growth factor ß (TGF-ß)/Rho kinase 1 (ROCK1) increased the stemness of BPH tissue by recruiting mesenchymal stem cells (MSCs), indicating the important role of embryonic reawakening in BPH. When TGF-ß/ROCK1 is abnormally activated, MSCs are recruited and differentiate into fibroblasts/myofibroblasts, leading to prostate stromal hyperplasia. Further research showed that inhibition of ROCK1 activation suppressed MSC migration and their potential for stromal differentiation. Collectively, our findings suggest that abnormal activation of TGF-ß/ROCK1 regulates stem cell lineage specificity, and the small molecule inhibitor GSK269962A could target ROCK1 and may be a potential treatment for BPH.

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Metabolic reprogramming plays a critical role in tumorigenesis and tumor progression. The metabolism and the proliferation of tumors are regulated by both intrinsic factors within the tumor and the availability of metabolites in the tumor microenvironment (TME). The metabolic niche within the TME is primarily orchestrated at 3 levels: 1) the regulation of tumor metabolism by factors intrinsic to the tumors, 2) the interaction between tumor cells and T cells, macrophages, and stromal cells, and 3) the metabolic heterogeneity of tumor cells within the tissue space. Herein, we provided a concise overview of the various metabolic regulatory modes observed in tumor cells. Additionally, we extensively analyzed the interaction between tumor cells and other cells within the TME, as well as the metabolic characteristics and functions of different types of cells. Ultimately, this review provides a theoretical basis and novel insights for the precision treatment of tumors.

The Expression of Serglycin Is Required for Active Transforming Growth Factor ß Receptor I Tumorigenic Signaling in Glioblastoma Cells and Paracrine Activation of Stromal Fibroblasts via CXCR-2.

Serglycin (SRGN) is a pro-tumorigenic proteoglycan expressed and secreted by various aggressive tumors including glioblastoma (GBM). In our study, we investigated the interplay and biological outcomes of SRGN with TGFßRI, CXCR-2 and inflammatory mediators in GBM cells and fibroblasts. SRGN overexpression is associated with poor survival in GBM patients. High SRGN levels also exhibit a positive correlation with increased levels of various inflammatory mediators including members of TGFß signaling pathway, cytokines and receptors including CXCR-2 and proteolytic enzymes in GBM patients. SRGN-suppressed GBM cells show decreased expressions of TGFßRI associated with lower responsiveness to the manipulation of TGFß/TGFßRI pathway and the regulation of pro-tumorigenic properties. Active TGFßRI signaling in control GBM cells promotes their proliferation, invasion, proteolytic and inflammatory potential. Fibroblasts cultured with culture media derived by control SRGN-expressing GBM cells exhibit increased proliferation, migration and overexpression of cytokines and proteolytic enzymes including CXCL-1, IL-8, IL-6, IL-1ß, CCL-20, CCL-2, and MMP-9. Culture media derived by SRGN-suppressed GBM cells fail to induce the above properties to fibroblasts. Importantly, the activation of fibroblasts by GBM cells not only relies on the expression of SRGN in GBM cells but also on active CXCR-2 signaling both in GBM cells and fibroblasts.

Results from the UNITED study: a multicenter study validating the prognostic effect of the tumor-stroma ratio in colon cancer.

BACKGROUND: The TNM (tumor-node-metastasis) Evaluation Committee of Union for International Cancer Control (UICC) and College of American Pathologists (CAP) recommended to prospectively validate the cost-effective and robust tumor-stroma ratio (TSR) as an independent prognostic parameter, since high intratumor stromal percentages have previously predicted poor patient-related outcomes. PATIENTS AND METHODS: The 'Uniform Noting for International application of Tumor-stroma ratio as Easy Diagnostic tool' (UNITED) study enrolled patients in 27 participating centers in 12 countries worldwide. The TSR, categorized as stroma-high (>50%) or stroma-low (≤50%), was scored through standardized microscopic assessment by certified pathologists, and effect on disease-free survival (DFS) was evaluated with 3-year median follow-up. Secondary endpoints were benefit assessment of adjuvant chemotherapy (ACT) and overall survival (OS). RESULTS: A total of 1537 patients were included, with 1388 eligible stage II/III patients curatively operated between 2015 and 2021. DFS was significantly shorter in stroma-high (n = 428) than in stroma-low patients (n = 960) (3-year rates 70% versus 83%; P < 0.001). In multivariate analysis, TSR remained an independent prognosticator for DFS (P < 0.001, hazard ratio 1.49, 95% confidence interval 1.17-1.90). As secondary outcome, DFS was also worse in stage II and III stroma-high patients despite adjuvant treatment (3-year rates stage II 73% versus 92% and stage III 66% versus 80%; P = 0.008 and P = 0.011, respectively). In stage II patients not receiving ACT (n = 322), the TSR outperformed the American Society of Clinical Oncology (ASCO) criteria in identifying patients at risk of events (event rate 21% versus 9%), with a higher discriminatory 3-year DFS rate (stroma-high 80% versus ASCO high risk 91%). A trend toward worse 5-year OS in stroma-high was noticeable (74% versus 83% stroma-low; P = 0.102). CONCLUSION: The multicenter UNITED study unequivocally validates the TSR as an independent prognosticator, confirming worse outcomes in stroma-high patients. The TSR improved current selection criteria for patients at risk of events, and stroma-high patients potentially experienced chemotherapy resistance. TSR implementation in pathology diagnostics and international guidelines is highly recommended as aid in personalized treatment.

Osteosarcoma cells exhibit functional interactions with stromal cells, fostering a lung microenvironment conducive to the establishment of metastatic tumor cells.

BACKGROUND: Osteosarcoma (OS) stands out as the most common bone tumor, with approximately 20% of the patients receiving a diagnosis of metastatic OS at their initial assessment. A significant challenge lies in the frequent existence of undetected metastases during the initial diagnosis. Mesenchymal stem cells (MSCs) possess unique abilities that facilitate tumor growth, and their interaction with OS cells is crucial for metastatic spread. METHODS AND RESULTS: We demonstrated that, in vitro, MSCs exhibited a heightened migration response toward the secretome of non-metastatic OS cells. When challenged to a secretome derived from lungs preloaded with OS cells, MSCs exhibited greater migration toward lungs colonized with metastatic OS cells. Moreover, in vivo, MSCs displayed preferential migratory and homing behavior toward lungs colonized by metastatic OS cells. Metastatic OS cells, in turn, demonstrated an increased migratory response to the MSCs' secretome. This behavior was associated with heightened cathepsin D (CTSD) expression and the release of active metalloproteinase 2 (MMP2) by metastatic OS cells. CONCLUSIONS: Our assessment focused on two complementary tumor capabilities crucial to metastatic spread, emphasizing the significance of inherent cell features. The findings underscore the pivotal role of signaling integration within the niche, with a complex interplay of migratory responses among established OS cells in the lungs, prometastatic OS cells in the primary tumor, and circulating MSCs. Pulmonary metastases continue to be a significant factor contributing to OS mortality. Understanding these mechanisms and identifying differentially expressed genes is essential for pinpointing markers and targets to manage metastatic spread and improve outcomes for patients with OS.

Adipose Tissue in Breast Cancer Microphysiological Models to Capture Human Diversity in Preclinical Models.

Female breast cancer accounts for 15.2% of all new cancer cases in the United States, with a continuing increase in incidence despite efforts to discover new targeted therapies. With an approximate failure rate of 85% for therapies in the early phases of clinical trials, there is a need for more translatable, new preclinical in vitro models that include cellular heterogeneity, extracellular matrix, and human-derived biomaterials. Specifically, adipose tissue and its resident cell populations have been identified as necessary attributes for current preclinical models. Adipose-derived stromal/stem cells (ASCs) and mature adipocytes are a normal part of the breast tissue composition and not only contribute to normal breast physiology but also play a significant role in breast cancer pathophysiology. Given the recognized pro-tumorigenic role of adipocytes in tumor progression, there remains a need to enhance the complexity of current models and account for the contribution of the components that exist within the adipose stromal environment to breast tumorigenesis. This review article captures the current landscape of preclinical breast cancer models with a focus on breast cancer microphysiological system (MPS) models and their counterpart patient-derived xenograft (PDX) models to capture patient diversity as they relate to adipose tissue.

STIM1/SOX2 proteins are co-expressed in the tumor and microenvironmental stromal cells of pancreatic ductal adenocarcinoma and ampullary carcinoma.

Pancreatic ductal adenocarcinoma (PDAC) and ampullary carcinoma (AAC) are lethal malignancies with modest benefits from surgery. SOX2 and STIM1 have been linked to anticancer activity in several human malignancies. This study included 94 tumor cases: 48 primary PDAC, 25 metastatic PDAC, and 21 primary AAC with corresponding non-tumor tissue. All cases were immunohistochemically stained for STIM1 and SOX2 and results were correlated with clinicopathologic data, patient survival, and BCL2 immunostaining results. Results revealed that STIM1 and SOX2 epithelial/stromal expressions were significantly higher in PDAC and AAC in comparison to the control groups. STIM1 and SOX2 expressions were positively correlated in the primary and metastatic PDAC (P = 0.016 and, P = 0.001, respectively). However, their expressions were not significantly associated with BCL2 expression. SOX2 epithelial/stromal expressions were positively correlated with the large tumor size in the primary AAC group (P = 0.052, P = 0.044, respectively). STIM1 stromal and SOX2 epithelial over-expressions had a bad prognostic impact on the overall survival of AAC (P = 0.002 and P = 0.001, respectively). Therefore, STIM1 and SOX2 co-expression in tumor cells and intra-tumoral stroma could contribute to the development of PDAC and AAC. STIM1/SOX2 expression is linked to a bad prognosis in AAC.

The critical role of the bone marrow stromal microenvironment for the development of drug screening platforms in leukemia.

Extensive research over the past 50 years has resulted in significant improvements in survival for patients diagnosed with leukemia. Despite this, a subgroup of patients harboring high-risk genetic alterations still suffer from poor outcomes. There is a desperate need for new treatments to improve survival, yet consistent failure exists in the translation of in vitro drug development to clinical application. Preclinical screening conventionally utilizes tumor cell monocultures to assess drug activity; however, emerging research has acknowledged the vital role of the tumor microenvironment in treatment resistance and disease relapse. Current co-culture drug screening methods frequently employ fibroblasts as the designated stromal cell component. Alternative stromal cell types that are known to contribute to chemoresistance are often absent in preclinical evaluations of drug efficacy. This review highlights mechanisms of chemoresistance by a range of different stromal constituents present in the bone marrow microenvironment. Utilizing an array of stromal cell types at the early stages of drug screening may enhance the translation of in vitro drug development to clinical use. Ultimately, we highlight the need to consider the bone marrow microenvironment in drug screening platforms for leukemia to develop superior therapies for the treatment of high-risk patients with poor prognostic outcomes.

Rebuilding the microenvironment of primary tumors in humans: a focus on stroma.

Conventional tumor models have critical shortcomings in that they lack the complexity of the human stroma. The heterogeneous stroma is a central compartment of the tumor microenvironment (TME) that must be addressed in cancer research and precision medicine. To fully model the human tumor stroma, the deconstruction and reconstruction of tumor tissues have been suggested as new approaches for in vitro tumor modeling. In this review, we summarize the heterogeneity of tumor-associated stromal cells and general deconstruction approaches used to isolate patient-specific stromal cells from tumor tissue; we also address the effect of the deconstruction procedure on the characteristics of primary cells. Finally, perspectives on the future of reconstructed tumor models are discussed, with an emphasis on the essential prerequisites for developing authentic humanized tumor models.

Transcription factor EB-mediated autophagy affects cell migration and inhibits apoptosis to promote endometriosis.

Autophagy has emerged as an important process of cell metabolism. With continuous in-depth research on autophagy, TFEB has been a key transcription factor regulating autophagy levels in recent years. Studies have established that TFEB regulates autophagy and apoptosis in various diseases. However, the relationship between TFEB and the pathogenesis of endometriosis remains unclear. This study aimed to investigate the effect of TFEB on the mechanism of endometriosis progression. The results showed that TFEB and autophagy-related protein LC3 are highly expressed in ectopic endometrium of patients with endometriosis, overexpression of TFEB in cultured human endometrial stromal cells (HESCs) by lentivirus not only promoted autophagy but also inhibited apoptosis. In addition, the migration and invasion ability of HESCs were enhanced by TFEB overexpression. Furthermore, inhibiting autophagy with specific inhibitors can attenuate migration and invasion of HESCs induced by TFEB. The rat models of endometriosis show that TFEB knockdown can suppress lesion growth in vivo. Our results suggest that autophagy may be involved in the progression mechanism of endometriosis, and the mechanism of autophagy disorder in endometriosis is probably related to TFEB. TFEB may be a key molecule in promoting endometriosis.

Stromal Signals Dominate Gene Expression Signature Scores That Aim to Describe Cancer Cell-intrinsic Stemness or Mesenchymality Characteristics.

Epithelial-to-mesenchymal transition (EMT) in cancer cells confers migratory abilities, a crucial aspect in the metastasis of tumors that frequently leads to death. In multiple studies, authors proposed gene expression signatures for EMT, stemness, or mesenchymality of tumors based on bulk tumor expression profiling. However, recent studies suggested that noncancerous cells from the microenvironment or macroenvironment heavily influence such signature profiles. Here, we strengthen these findings by investigating 11 published and frequently referenced gene expression signatures that were proposed to describe EMT-related (EMT, mesenchymal, or stemness) characteristics in various cancer types. By analyses of bulk, single-cell, and pseudobulk expression data, we show that the cell type composition of a tumor sample frequently dominates scores of these EMT-related signatures. A comprehensive, integrated analysis of bulk RNA sequencing (RNA-seq) and single-cell RNA-seq data shows that stromal cells, most often fibroblasts, are the main drivers of EMT-related signature scores. We call attention to the risk of false conclusions about tumor properties when interpreting EMT-related signatures, especially in a clinical setting: high patient scores of EMT-related signatures or calls of "stemness subtypes" often result from low cancer cell content in tumor biopsies rather than cancer cell-specific stemness or mesenchymal/EMT characteristics. SIGNIFICANCE: Cancer self-renewal and migratory abilities are often characterized via gene module expression profiles, also called EMT or stemness gene expression signatures. Using published clinical tumor samples, cancer cell lines, and single cancer cells, we highlight the dominating influence of noncancer cells in low cancer cell content biopsies on their scores. We caution on their application for low cancer cell content clinical cancer samples with the intent to assign such characteristics or subtypes.

Single-Cell Analysis Identifies NOTCH3-Mediated Interactions between Stromal Cells That Promote Microenvironment Remodeling and Invasion in Lung Adenocarcinoma.

Cancer immunotherapy has revolutionized the treatment of lung adenocarcinoma (LUAD); however, a significant proportion of patients do not respond. Recent transcriptomic studies to understand determinants of immunotherapy response have pinpointed stromal-mediated resistance mechanisms. To gain a better understanding of stromal biology at the cellular and molecular level in LUAD, we performed single-cell RNA sequencing of 256,379 cells, including 13,857 mesenchymal cells, from 9 treatment-naïve patients. Among the mesenchymal cell subsets, FAP+PDPN+ cancer-associated fibroblasts (CAF) and ACTA2+MCAM+ pericytes were enriched in tumors and differentiated from lung-resident fibroblasts. Imaging mass cytometry revealed that both subsets were topographically adjacent to the perivascular niche and had close spatial interactions with endothelial cells (EC). Modeling of ligand and receptor interactomes between mesenchymal and ECs identified that NOTCH signaling drives these cell-to-cell interactions in tumors, with pericytes and CAFs as the signal receivers and arterial and PLVAPhigh immature neovascular ECs as the signal senders. Either pharmacologically blocking NOTCH signaling or genetically depleting NOTCH3 levels in mesenchymal cells significantly reduced collagen production and suppressed cell invasion. Bulk RNA sequencing data demonstrated that NOTCH3 expression correlated with poor survival in stroma-rich patients and that a T cell-inflamed gene signature only predicted survival in patients with low NOTCH3. Collectively, this study provides valuable insights into the role of NOTCH3 in regulating tumor stroma biology, warranting further studies to elucidate the clinical implications of targeting NOTCH3 signaling. SIGNIFICANCE: NOTCH3 signaling activates tumor-associated mesenchymal cells, increases collagen production, and augments cell invasion in lung adenocarcinoma, suggesting its critical role in remodeling tumor stroma.

Juan-tong-yin potentially impacts endometriosis pathophysiology by enhancing autophagy of endometrial stromal cells via unfolded protein reaction-triggered endoplasmic reticulum stress.

ETHNOPHARMACOLOGICAL RELEVANCE: Endometriosis (EMs) is characterized by inflammatory lesions, dysmenorrhea, infertility, and chronic pelvic pain. Single-target medications often fail to provide systemic therapeutic results owing to the complex mechanism underlying endometriosis. Although traditional Chinese medicines-such as Juan-Tong-Yin (JTY)-have shown promising results, their mechanisms of action remain largely unknown. AIM OF THE STUDY: To elucidate the therapeutic mechanism of JTY in EMs, focusing on endoplasmic reticulum (ER) stress-induced autophagy. MATERIALS AND METHODS: The major components of JTY were detected using high-performance liquid chromatography-mass spectrometry (HPLC-MS). The potential mechanism of JTY in EMs treatment was predicted using network pharmacological analysis. Finally, the pathogenesis of EMs was validated in a clinical case-control study and the molecular mechanism of JTY was validated in vitro using endometrial stromal cells (ESCs). RESULTS: In total, 241 compounds were analyzed and identified from JTY using UPLC-MS. Network pharmacology revealed 288 targets between the JTY components and EMs. Results of the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analyses indicated that regulating autophagy, migration, apoptosis, and inflammation were the key mechanisms of JTY in treating EMs. Meanwhile, we found that protein kinase R-like endoplasmic reticulum kinase (PERK), Beclin-1, and microtubule-associated protein light chain 3 B (LC3B) expressions were lower in endometria of patients with EMs than in those with normal eutopic endometria (p < 0.05). Additionally, during in vitro experiments, treatment with 20% JTY-containing serum significantly suppressed ESC proliferation, achieving optimal effects after 48 h. Electron microscopy revealed significantly increased autophagy flux in the JTY group compared with the control group. Moreover, JTY treatment significantly reduced the migratory and invasive abilities of ESCs and upregulated protein expression of PERK, eukaryotic initiation factor 2α (eIF2α)/phospho-eukaryotic initiation factor 2α (p-eIF2α), activating Transcription Factor-4 (ATF4), Beclin-1, and LC3BII/I, while subsequently downregulating NOD-like receptor thermal protein domain associated protein 3 (NLRP3) and interleukin 18 (IL-18) expression. However, administration of GSK2656157-a highly selective PERK inhibitor-reversed these changes. CONCLUSION: JTY ameliorates EMs by activating PERK associated with unfolded protein reaction, enhancing cell ER stress and autophagy, improving the inflammatory microenvironment, and decreasing the migration and invasion of ESCs.

Improved Efficacy of Delayed Treatment with Human Bone Marrow-Derived Stromal Cells Evaluated in Rats with Spinal Cord Injury.

The treatment of spinal cord injury (SCI) with uncultivated human bone marrow-derived stromal cells (bmSCs) prepared by negative selection has been proposed to be therapeutically superior to treatment with stem cells that were expanded in vitro. To explore their use in clinical trials, we studied the functional effects of delayed application at 7 days after SCI by testing different doses of bmSCs. Spinal cord contusion injury was induced in adult male Wistar rats at the thoracic level T9. Human bmSCs were prepared by negative selection without expansion in vitro (NeuroCellsTM). Treatment consisted of one 150 µL injection into the cisterna magna containing 0.5 or 2.5 million fresh bmSCs or 2.5 million bmSCs. The recovery of motor functions was evaluated during a surveillance period of six weeks (6 W), during which spinal cords were assessed histologically. Treatment resulted in a significant, dose-dependent therapeutic effect on the recovery of motor performance. The histological analysis revealed a lower degree of axonal degeneration and better survival of neurons and oligodendrocytes in bmSCs treated rats. Our results support delayed intrathecal application of bmSCs prepared by negative selection without expansion in vitro as a treatment of SCI.

SAA1-dependent reprogramming of adipocytes by tumor cells is associated with triple negative breast cancer aggressiveness.

Triple negative breast cancers (TNBC) are characterized by a poor prognosis and a lack of targeted treatments. Their progression depends on tumor cell intrinsic factors, the tumor microenvironment and host characteristics. Although adipocytes, the primary stromal cells of the breast, have been determined to be plastic in physiology and cancer, the tumor-derived molecular mediators of tumor-adipocyte crosstalk have not been identified yet. In this study, we report that the crosstalk between TNBC cells and adipocytes in vitro beyond adipocyte dedifferentiation, induces a unique transcriptional profile that is characterized by inflammation and pathways that are related to interaction with the tumor microenvironment. Accordingly, increased cancer stem-like features and recruitment of pro-tumorigenic immune cells are induced by this crosstalk through CXCL5 and IL-8 production. We identified serum amyloid A1 (SAA1) as a regulator of the adipocyte reprogramming through CD36 and P2XR7 signaling. In human TNBC, SAA1 expression was associated with cancer-associated adipocyte infiltration, inflammation, stimulated lipolysis, stem-like properties, and a distinct tumor immune microenvironment. Our findings constitute evidence that the interaction between tumor cells and adipocytes through the release of SAA1 is relevant to the aggressiveness of TNBC.

Mesenteric fibrosis in patients with small intestinal neuroendocrine tumors is associated with enrichment of alpha-smooth muscle actin-positive fibrosis and COMP-expressing stromal cells.

Neuroendocrine tumors of the small intestine (SI-NETs) often develop lymph node metastasis (LNM)-induced mesenteric fibrosis (MF). MF can cause intestinal obstruction as well as ischemia and render surgical resection technically challenging. The underlying pathomechanisms of MF are still not well understood. We examined mesenteric LNM and the surrounding stroma compartment from 24 SI-NET patients, including 11 with in situ presentation of strong MF (MF+) and 13 without MF (MF-). Differential gene expression was assessed with the HTG EdgeSeq Oncology Biomarker Panel comparing MF+ with MF- within LNM and paired stromal samples, respectively. Most interesting differentially expressed genes were validated by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) in combination with validation of associated protein levels utilizing immunohistochemistry (IHC) staining of MF+ and MF- formalin-fixed, paraffin-embedded (FFPE) patient samples. Overall, 14 genes measured with a 2549-gene expression panel were differentially expressed in MF+ patients compared to MF-. Of those, nine were differentially expressed genes in LNM and five genes in the stromal tissue (>2-fold change, p < .05). The top hits included increased COMP and COL11A1 expression in the stroma of MF+ patients compared to MF-, as well as decreased HMGA2, COL6A6, and SLC22A3 expression in LNM of MF+ patients compared to LNM of MF- patients. RT-qPCR confirmed high levels of COMP and COL11A1 in stroma samples of MF+ compared to MF- patients. IHC staining confirmed the enrichment of α-smooth muscle actin-positive fibrosis in MF+ compared to MF- patients with corresponding increase of COMP-expressing stromal cells in MF+. Since COMP is associated with the known driver for fibrosis development transforming growth factor beta and with a cancer-associated fibroblasts enriched environment, it seems to be a promising new target for MF research.

Harnessing the therapeutic potential of mesenchymal stem/stromal cell-derived extracellular vesicles as a novel cell-free therapy for animal models of multiple sclerosis.

Multiple sclerosis (MS) is a chronic, neuroinflammatory, and demyelinating disease of the central nervous system (CNS). Current treatments offer only limited relief from symptoms, and there is no cure. Mesenchymal stem/stromal cells (MSCs) have demonstrated therapeutic potential for MS. However, their clinical application faces challenges, including immune rejection and the potential for tumor formation. Recent studies suggest that MSCs exert their effects through extracellular vesicles (EVs) released from the cells, rather than direct cellular engraftment or differentiation. This discovery has sparked interest in the potential of MSC-derived EVs as a cell-free therapy for MS. This review explores the existing literature on the effects of MSC-EVs in animal models of MS. Administration of MSC-EVs from various tissue sources, such as bone marrow, adipose tissue, and umbilical cord, was found to reduce clinical scores and slow down disease progression in experimental autoimmune encephalomyelitis (EAE), the primary mouse model of MS. The mechanisms involved immunomodulation through effects on T cells, cytokines, CNS inflammation, and demyelination. Although the impact on CNS repair markers remained unclear, MSC-EVs exhibited the potential to modulate neuroinflammation and suppress harmful immune responses in EAE. Further studies are still required, but MSC-EVs demonstrate promising therapeutic effects for MS and warrant further exploration as a novel treatment approach.