The Extracellular Matrix in Soft Tissue Sarcomas: Pathobiology and Cellular Signalling

Clinical Implications and Molecular Features of Extracellular Matrix Networks in Soft Tissue Sarcomas

PURPOSE

The landscape of extracellular matrix (ECM) alterations in soft tissue sarcomas (STS) remains poorly characterized. We aimed to investigate the tumor ECM and adhesion signaling networks present in STS and their clinical implications.

EXPERIMENTAL DESIGN

Proteomic and clinical data from 321 patients across 11 histological subtypes were analyzed to define ECM and integrin adhesion networks. Subgroup analysis was performed in leiomyosarcomas (LMS), dedifferentiated liposarcomas (DDLPS), and undifferentiated pleomorphic sarcomas (UPS).

RESULTS

This analysis defined subtype-specific ECM profiles including enrichment of basement membrane proteins in LMS and ECM proteases in UPS. Across the cohort, we identified three distinct coregulated ECM networks which are associated with tumor malignancy grade and histological subtype. Comparative analysis of LMS cell line and patient proteomic data identified the lymphocyte cytosolic protein 1 cytoskeletal protein as a prognostic factor in LMS. Characterization of ECM network events in DDLPS revealed three subtypes with distinct oncogenic signaling pathways and survival outcomes. Evaluation of the DDLPS subtype with the poorest prognosis nominates ECM remodeling proteins as candidate antistromal therapeutic targets. Finally, we define a proteoglycan signature that is an independent prognostic factor for overall survival in DDLPS and UPS.

CONCLUSIONS

STS comprise heterogeneous ECM signaling networks and matrix-specific features that have utility for risk stratification and therapy selection, which could in future guide precision medicine in these rare cancers.

Oncogene-induced matrix reorganization controls CD8+ T cell function in the soft-tissue sarcoma microenvironment

CD8+ T cell dysfunction impedes antitumor immunity in solid cancers, but the underlying mechanisms are diverse and poorly understood. Extracellular matrix (ECM) composition has been linked to impaired T cell migration and enhanced tumor progression; however, impacts of individual ECM molecules on T cell function in the tumor microenvironment (TME) are only beginning to be elucidated. Upstream regulators of aberrant ECM deposition and organization in solid tumors are equally ill-defined. Therefore, we investigated how ECM composition modulates CD8+ T cell function in undifferentiated pleomorphic sarcoma (UPS), an immunologically active desmoplastic tumor. Using an autochthonous murine model of UPS and data from multiple human patient cohorts, we discovered a multifaceted mechanism wherein the transcriptional coactivator YAP1 promotes collagen VI (COLVI) deposition in the UPS TME. In turn, COLVI induces CD8+ T cell dysfunction and immune evasion by remodeling fibrillar collagen and inhibiting T cell autophagic flux. Unexpectedly, collagen I (COLI) opposed COLVI in this setting, promoting CD8+ T cell function and acting as a tumor suppressor. Thus, CD8+ T cell responses in sarcoma depend on oncogene-mediated ECM composition and remodeling.

Translational Aspects of Epithelioid Sarcoma: Current Consensus

Epithelioid sarcoma (EpS) is an ultra-rare malignant soft-tissue cancer mostly affecting adolescents and young adults. EpS often exhibits an unfavorable clinical course with fatal outcome in ∼50% of cases despite aggressive multimodal therapies combining surgery, chemotherapy, and irradiation. EpS is traditionally classified in a more common, less aggressive distal (classic) type and a rarer aggressive proximal type. Both subtypes are characterized by a loss of nuclear INI1 expression, most often following homozygous deletion of its encoding gene, SMARCB1-a core subunit of the SWI/SNF chromatin remodeling complex. In 2020, the EZH2 inhibitor tazemetostat was the first targeted therapy approved for EpS, raising new hopes. Still, the vast majority of patients did not benefit from this drug or relapsed rapidly. Further, other recent therapeutic modalities, including immunotherapy, are only effective in a fraction of patients. Thus, novel strategies, specifically targeted to EpS, are urgently needed. To accelerate translational research on EpS and eventually boost the discovery and development of new diagnostic tools and therapeutic options, a vibrant translational research community has formed in past years and held two international EpS digital expert meetings in 2021 and 2023. This review summarizes our current understanding of EpS from the translational research perspective and points to innovative research directions to address the most pressing questions in the field, as defined by expert consensus and patient advocacy groups.

GALNT12 promotes fibrosarcoma growth by accelerating YAP1 nuclear localization

Fibrosarcoma is a highly malignant type of soft tissue sarcoma that currently lacks effective treatment options. Polypeptide N-acetylgalactosaminyltransferase 12 (GALNT12) belongs to the uridine diphosphate N-acetylgalactosamine gene family, which is involved in numerous biological processes of diseases, such as tumor progression. Its upregulated expression is closely associated with the development of colorectal cancer. However, research on the role of GALNT12 in fibrosarcoma is currently limited. The present study aimed to assess the expression and biological function of GALNT12 in fibrosarcoma. Patient data and tissue samples were collected and public datasets were obtained from the Gene Expression Omnibus (GSE24369 and GSE21124). Immunofluorescence assays were performed to observe the cellular localization of GALNT12. GALNT12 expression was measured using reverse transcription-quantitative PCR, western blotting and immunohistochemistry. Small interfering RNAs were constructed to knock down GALNT12 expression in HT-1080 cells. Cell Counting Kit-8 and EdU assays were used to assess fibrosarcoma cell proliferation. Wound healing and Transwell assays were used to detect migration. Gene set enrichment analysis was performed to identify key pathways. Paired and unpaired Student's t-test, Fisher's exact test and one-way ANOVA (followed by Tukey's Honest Significant Difference test) were used to analyze the data. It was demonstrated that GALNT12 expression was upregulated in both fibrosarcoma cell lines and tissue samples and predicted poor patient prognosis. In vitro experiments demonstrated that high GALNT12 expression levels significantly increased HT-1080 cell proliferation and migration. Furthermore, it was demonstrated that high GALNT12 expression levels were closely associated with the yes1 associated transcriptional regulator (YAP1) signaling pathway. Knockdown of GALNT12 inhibited YAP1 nuclear translocation, which affected activation of key downstream genes including AMOTL2, BIRC5 and CYR61. Therefore, the present study demonstrated that GALNT12 promoted fibrosarcoma progression. GALNT12 could be a potential biomarker for this disease and may potentially provide new ideas for targeted therapy of fibrosarcoma in the future.

Patient-Derived Organoids as a Promising Tool for Multimodal Management of Sarcomas

The management of sarcomas, a diverse group of cancers arising from connective tissues, presents significant challenges due to their heterogeneity and limited treatment options. Patient-derived sarcoma organoids (PDSOs) have emerged as a promising tool in the multimodal management of sarcomas, offering unprecedented opportunities for personalized medicine and improved treatment strategies. This review aims to explore the potential of PDSOs as a promising tool for multimodal management of sarcomas. We discuss the establishment and characterization of PDSOs, which realistically recapitulate the complexity and heterogeneity of the original tumor, providing a platform for genetic and molecular fidelity, histological resemblance, and functional characterization. Additionally, we discuss the applications of PDSOs in pathological and genetic evaluation, treatment screening and development, and personalized multimodal management. One significant advancement of PDSOs lies in their ability to guide personalized treatment decisions, enabling clinicians to assess the response and efficacy of different therapies in a patient-specific manner. Through continued research and development, PDSOs hold the potential to revolutionize sarcoma management and drive advancements in personalized medicine, biomarker discovery, preclinical modeling, and therapy optimization. The integration of PDSOs into clinical practice can ultimately improve patient outcomes and significantly impact the field of sarcoma treatment.

The In Vitro Effects of Romina Strawberry Extract on 3D Uterine Leiomyosarcoma Cells

Leiomyosarcoma is an aggressive soft tissue sarcoma derived from the smooth muscle cells of the uterus. We tested the effect of Romina strawberry extract treatment on three-dimensional cultured uterine leiomyosarcoma cells. We established 3D cultures in agarose gel, where the cells seeded were able to form spheroids. We performed the observation and counting of the spheroids with a phase-contrast optical microscope, finding a decrease in the number of spheroids formed in the plates after 24 and 48 h treatment with 250 µg/mL of cultivar Romina strawberry extract. We also characterized the spheroids morphology by DNA binding fluorescent-stain observation, hematoxylin and eosin stain, and Masson's trichrome stain. Finally, the real-time PCR showed a reduced expression of extracellular matrix genes after strawberry treatment. Overall, our data suggest that the fruit extract of this strawberry cultivar may be a useful therapeutic adjuvant for the management of uterine leiomyosarcoma.

Fibroblast Activation Protein Inhibitor (FAPI)-PET Imaging in Sarcoma

Advances in histopathologic and molecular genetic subtyping of sarcoma will potentially allow identification of novel diagnostic and therapeutic targets for specific subtypes, but a "pan-sarcoma" target is needed. This article provides an overview on expression of one potential candidate, fibroblast activation protein alpha in soft tissue and bone sarcoma, and the resulting application of 68Ga-FAPI as novel imaging probes in these rare tumor entities. Current preclinical and clinical data on 68Ga-FAPI-PET/CT in sarcomas are summarized. 68Ga-FAPI-PET-CT potentially offers important complementary information to be used in diagnostic work-up, assessment of therapy response, and prognostication of soft tissue and bone sarcomas.

Clinical Prognostic Factors and Integrated Multi-Omics Studies Identify Potential Novel Therapeutic Targets for Pediatric Desmoid Tumor

BACKGROUND

Desmoid tumor (DT), also known as desmoid-type fibromatosis (DTF) or aggressive fibromatosis (AF) is a rare mesenchymal tumor affecting both children and adults. It is non-metastasis but infiltrative, growing with a high recurrence rate to even cause serious health problems. This study investigates the biology of desmoid tumors through integrated multi-omics studies.

METHODS

We systematically investigated the clinical data of 98 extra-abdominal cases in our pediatric institute and identified some critical clinical prognostic factors. Moreover, our integrated multi-omics studies (Whole Exome Sequencing, RNA sequencing, and untargeted metabolomics profiling) in the paired PDT tumor/matched normal tissues identified more novel mutations, and potential prognostic markers and therapeutic targets for PDTs.

RESULTS

The top mutation genes, such as CTNNB1 (p.T41A and p.S45F) and MUC4 (p.T3775T, p.S3450S, etc.), were observed with a mutation in more than 40% of PDT patients. We also identified a panel of genes that are classed as the FDA-approved drug targets or Wnt/β-catenin signaling pathway-related genes. The integrated analysis identified pathways and key genes/metabolites that may be important for developing potential treatment of PDTs. We also successfully established six primary PDT cell lines for future studies.

CONCLUSIONS

These studies may promote the development of novel drugs and therapeutic strategies for PDTs.