Extracellular Collagen Mediates Osteosarcoma Progression Through an Integrin α2β1/JAK/STAT3 Signaling Pathway

Repurposing the diuretic benzamil as an anti-osteosarcoma agent that acts by suppressing integrin/FAK/STAT3 signalling and compromising mitochondrial function

Aims

Osteosarcoma is the most common primary bone malignancy among children and adolescents. We investigated whether benzamil, an amiloride analogue and sodium-calcium exchange blocker, may exhibit therapeutic potential for osteosarcoma in vitro.

Methods

MG63 and U2OS cells were treated with benzamil for 24 hours. Cell viability was evaluated with the MTS/PMS assay, colony formation assay, and flow cytometry (forward/side scatter). Chromosome condensation, the terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) assay, cleavage of poly-ADP ribose polymerase (PARP) and caspase-7, and FITC annexin V/PI double staining were monitored as indicators of apoptosis. Intracellular calcium was detected by flow cytometry with Fluo-4 AM. The phosphorylation and activation of focal adhesion kinase (FAK) and signal transducer and activator of transcription 3 (STAT3) were measured by western blot. The expression levels of X-linked inhibitor of apoptosis protein (XIAP), B-cell lymphoma 2 (Bcl-2), B-cell lymphoma-extra large (Bcl-xL), SOD1, and SOD2 were also assessed by western blot. Mitochondrial status was assessed with tetramethylrhodamine, ethyl ester (TMRE), and intracellular adenosine triphosphate (ATP) was measured with BioTracker ATP-Red Live Cell Dye. Total cellular integrin levels were evaluated by western blot, and the expression of cell surface integrins was assessed using fluorescent-labelled antibodies and flow cytometry.

Results

Benzamil suppressed growth of osteosarcoma cells by inducing apoptosis. Benzamil reduced the expression of cell surface integrins α5, αV, and β1 in MG63 cells, while it only reduced the expression of αV in U2OS cells. Benzamil suppressed the phosphorylation and activation of FAK and STAT3. In addition, mitochondrial function and ATP production were compromised by benzamil. The levels of anti-apoptotic proteins XIAP, Bcl-2, and Bcl-xL were reduced by benzamil. Correspondingly, benzamil potentiated cisplatin- and methotrexate-induced apoptosis in osteosarcoma cells.

Conclusion

Benzamil exerts anti-osteosarcoma activity by inducing apoptosis. In terms of mechanism, benzamil appears to inhibit integrin/FAK/STAT3 signalling, which triggers mitochondrial dysfunction and ATP depletion.

Effect of traditional Chinese medicine in osteosarcoma: Cross-interference of signaling pathways and potential therapeutic targets

Osteosarcoma (OS) has a high recurrence rate, disability rate, mortality and metastasis, it brings great economic burden and psychological pressure to patients, and then seriously affects the quality of life of patients. At present, the treatment methods of OS mainly include radiotherapy, chemotherapy, surgical therapy and neoadjuvant chemotherapy combined with limb salvage surgery. These treatment methods can relieve the clinical symptoms of patients to a certain extent, and also effectively reduce the disability rate, mortality and recurrence rate of OS patients. However, because metastasis of tumor cells leads to new complications, and OS cells become resistant with prolonged drug intervention, which reduces the sensitivity of OS cells to drugs, these treatments still have some limitations. More and more studies have shown that traditional Chinese medicine (TCM) has the characteristics of "multiple targets and multiple pathways," and can play an important role in the development of OS through several key signaling pathways, including PI3K/AKT, Wnt/β-catenin, tyrosine kinase/transcription factor 3 (JAK/STAT3), Notch, transforming growth factor-β (TGF-β)/Smad, nuclear transcription factor-κB (NF-κB), mitogen-activated protein kinase (MAPK), nuclear factor E2-related factor 2 (Nrf2), Hippo/YAP, OPG/RANK/RANKL, Hedgehog and so on. In this paper, the signaling pathways of cross-interference between active ingredients of TCM and OS were reviewed, and the development status of novel OS treatment was analyzed. The active ingredients in TCM can provide therapeutic benefits to patients by targeting the activity of signaling pathways. In addition, potential strategies for targeted therapy of OS by using ferroptosis were discussed. We hope to provide a unique insight for the in-depth research and clinical application of TCM in the fields of OS growth, metastasis and chemotherapy resistance by understanding the signaling crosstalk between active ingredients in TCM and OS.

The characteristics and the multiple functions of integrin β1 in human cancers

Integrins, which consist of two non-covalently linked α and β subunits, play a crucial role in cell-cell adhesion and cell-extracellular matrix (ECM) interactions. Among them, integrin β1 is the most common subunit and has emerged as a key mediator in cancer, influencing various aspects of cancer progression, including cell motility, adhesion, migration, proliferation, differentiation and chemotherapy resistance. However, given the complexity and sometimes contradictory characteristics, targeting integrin β1 for therapeutics has been a challenge. The emerging understanding of the mechanisms regulating by integrin β1 may guide the development of new strategies for anti-cancer therapy. In this review, we summarize the multiple functions of integrin β1 and signaling pathways which underlie the involvement of integrin β1 in several malignant cancers. Our review suggests the possibility of using integrin β1 as a therapeutic target and highlights the need for patient stratification based on expression of different integrin receptors in future clinical studies.

Analysis of intercellular communication in the osteosarcoma microenvironment based on single cell sequencing data

Osteosarcoma (OS) is the most common primary bone cancer in children and young adults, patient survival rates have not improved in recent decades. To further understand the interrelationship between different cell types in the tumor microenvironment of osteosarcoma, we comprehensively analyzed single-cell sequencing data from six patients with untreated osteosarcoma. Nine major cell types were identified from a total of 46,046 cells based on unbiased clustering of gene expression profiles and canonical markers. Osteosarcoma from different patients display heterogeneity in cellular composition. Myeloid cells were the most commonly represented cell type, followed by osteoblastic and TILs. Copy number variation (CNV) results identified amplifications and deletions in malignant osteoblastic cells and fibroblasts. Trajectory analysis based on RNA velocity showed that osteoclasts in the OS microenvironment could be differentiated from myeloid cells. Furthermore, we explored the intercellular communications in OS microenvironment and identified multiple ligand-receptor pairs between myeloid cells, osteoblastic cells and their cells, including 21 ligand-receptor pair genes that significantly associated with survival outcomes. Importantly, we found chemotherapy may have an effect on cellular communication in the OS microenvironment by analyzing single-cell sequencing data from seven primary osteosarcoma patients who received chemotherapy. We believe these observations will improve our understanding of potential mechanisms of microenvironment contributions to OS progression and help identify potential targets for new treatment development in the future.

Targeting signaling pathways in osteosarcoma: Mechanisms and clinical studies

Osteosarcoma (OS) is a highly prevalent bone malignancy among adolescents, accounting for 40% of all primary malignant bone tumors. Neoadjuvant chemotherapy combined with limb-preserving surgery has effectively reduced patient disability and mortality, but pulmonary metastases and OS cells' resistance to chemotherapeutic agents are pressing challenges in the clinical management of OS. There has been an urgent need to identify new biomarkers for OS to develop specific targeted therapies. Recently, the continued advancements in genomic analysis have contributed to the identification of clinically significant molecular biomarkers for diagnosing OS, acting as therapeutic targets, and predicting prognosis. Additionally, the contemporary molecular classifications have revealed that the signaling pathways, including Wnt/β-catenin, PI3K/AKT/mTOR, JAK/STAT3, Hippo, Notch, PD-1/PD-L1, MAPK, and NF-κB, have an integral role in OS onset, progression, metastasis, and treatment response. These molecular classifications and biological markers have created new avenues for more accurate OS diagnosis and relevant treatment. We herein present a review of the recent findings for the modulatory role of signaling pathways as possible biological markers and treatment targets for OS. This review also discusses current OS therapeutic approaches, including signaling pathway-based therapies developed over the past decade. Additionally, the review covers the signaling targets involved in the curative effects of traditional Chinese medicines in the context of expression regulation of relevant genes and proteins through the signaling pathways to inhibit OS cell growth. These findings are expected to provide directions for integrating genomic, molecular, and clinical profiles to enhance OS diagnosis and treatment.

The role of integrin family in bone metabolism and tumor bone metastasis

Integrins have been the research focus of cell-extracellular matrix adhesion (ECM) and cytokine receptor signal transduction. They are involved in the regulation of bone metabolism of bone precursor cells, mesenchymal stem cells (MSCs), osteoblasts (OBs), osteoclasts (OCs), and osteocytes. Recent studies expanded and updated the role of integrin in bone metabolism, and a large number of novel cytokines were found to activate bone metabolism pathways through interaction with integrin receptors. Integrins act as transducers that mediate the regulation of bone-related cells by mechanical stress, fluid shear stress (FSS), microgravity, hypergravity, extracellular pressure, and a variety of physical factors. Integrins mediate bone metastasis of breast, prostate, and lung cancer by promoting cancer cell adhesion, migration, and survival. Integrin-mediated targeted therapy showed promising prospects in bone metabolic diseases. This review emphasizes the latest research results of integrins in bone metabolism and bone metastasis and provides a vision for treatment strategies.

Association of chondroadherin with leiomyosarcoma

The leiomyosarcoma (LMS) subtype of uterine sarcoma accounts for 1-2 % of uterine neoplasia cases. The present study aimed to demonstrate that the gene and protein chondroadherin (CHAD) levels may serve as novel biomarkers for predicting prognosis and devising novel treatment models for LMS. A total of 12 patients diagnosed with LMS and 13 patients diagnosed with myomas were included in the study. The extent of tumour cell necrosis, cellularity and atypia and the mitotic index of each patient with LMS were determined. CHAD gene expression was significantly increased in cancerous tissues compared with that in fibroid tissues (2.17 ± 0.88 vs 3.19 ± 1.61; P = 0.047). The mean CHAD protein expression in tissues was higher in LMS cases but this was not statistically significant (217.38 ± 93.9 vs 177.13 ± 66.67;P = 0.226). Positive significant correlations were obtained between CHAD gene expression and mitotic index (r = 0.476; P = 0.008), tumour size (r = 0.385; P = 0.029) and necrosis (r = 0.455; P = 0.011). Furthermore, there were significant positive correlations between CHAD protein expression levels and tumour size (r = 0.360; P = 0.039) and necrosis (r = 0.377; P = 0.032). The present study was the first to demonstrate the significance of CHAD in LMS. The results suggested that, due to its association with LMS, CHAD has predictive value in determining the prognosis of patients with LMS.

From the Matrix to the Nucleus and Back: Mechanobiology in the Light of Health, Pathologies, and Regeneration of Oral Periodontal Tissues

Among oral tissues, the periodontium is permanently subjected to mechanical forces resulting from chewing, mastication, or orthodontic appliances. Molecularly, these movements induce a series of subsequent signaling processes, which are embedded in the biological concept of cellular mechanotransduction (MT). Cell and tissue structures, ranging from the extracellular matrix (ECM) to the plasma membrane, the cytosol and the nucleus, are involved in MT. Dysregulation of the diverse, fine-tuned interaction of molecular players responsible for transmitting biophysical environmental information into the cell's inner milieu can lead to and promote serious diseases, such as periodontitis or oral squamous cell carcinoma (OSCC). Therefore, periodontal integrity and regeneration is highly dependent on the proper integration and regulation of mechanobiological signals in the context of cell behavior. Recent experimental findings have increased the understanding of classical cellular mechanosensing mechanisms by both integrating exogenic factors such as bacterial gingipain proteases and newly discovered cell-inherent functions of mechanoresponsive co-transcriptional regulators such as the Yes-associated protein 1 (YAP1) or the nuclear cytoskeleton. Regarding periodontal MT research, this review offers insights into the current trends and open aspects. Concerning oral regenerative medicine or weakening of periodontal tissue diseases, perspectives on future applications of mechanobiological principles are discussed.