Tspan9 Induces EMT and Promotes Osteosarcoma Metastasis via Activating FAK-Ras-ERK1/2 Pathway

Promoting mitocytosis via gene-engineered aligned fibers for fascia regeneration

The abnormal accumulation of damaged mitochondria severely impedes tissue repair, and conventional therapeutic approaches, such as drug treatments, are often ineffective to remove damaged mitochondria. In this study, we developed gene-engineered aligned electrospun fibers by integrating microfluidic chip technology with a micro-sol oriented electrospinning technique. This study is the first to demonstrate the repair of damaged fascia by promoting mitocytosis through upregulating tetraspanin-9 (TSPAN9). The key gene for mitochondrial exocytosis, TSPAN9, was initially encapsulated into liposomes using microfluidic chip technology. Subsequently, core-shell structured aligned electrospun fibers were fabricated via oriented micro-sol electrospinning, where TSPAN9-loaded liposomes were protected by hyaluronic acid (HA) in the core layer, while aligned polylactic acid (PLA) fibers formed the outer shell layer. In vitro studies revealed that the aligned fibers closely mimicked the oriented structure of fascia tissue and significantly enhanced cell migration by providing directional physical cues. By sustained release of gene-loaded liposomes into cells, mitochondrial homeostasis was effectively restored, mitochondrial respiration was recovered, reactive oxygen species levels were reduced, and mitochondrial membrane potential was maintained. In vivo studies confirmed that these gene-engineered fibers effectively suppressed inflammatory responses and promoted fascia regeneration by facilitating the removal of damaged mitochondria through mitocytosis. In conclusion, gene-engineered fibers developed in this study, which enhance mitocytosis, offer a novel and promising therapeutic strategy for fascia tissue repair.

Identification of potential causal genes and drug targets in pulmonary hypertension based on transcriptomic analysis and Mendelian randomization

PURPOSE

Currently, there is no definitive treatment for pulmonary hypertension (PH). This study aims to utilize the GEO database and conduct Mendelian randomization (MR) analysis to identify new genetic targets for PH and investigate their potential pathogenic pathways and therapeutic drugs.

METHODS

We identified key genes by combining the findings from MR and bioinformatics analyses of GEO datasets. We performed enrichment analysis to explore the functional roles of these key genes. Then, we constructed protein-protein interaction (PPI) and miRNA-mRNA networks to identify interacting proteins and miRNAs. Drug prediction analysis was conducted to propose potential therapeutic drugs. Finally, we validated the results through the GEO dataset, RT-PCR, and western blot experiments.

RESULTS

The joint analysis utilizing GEO databases and MR analysis identified two key genes, ITGA2B and TSPAN9 that exhibited significance across both analytical methods. The enrichment analysis indicated that the key genes were involved in critical biological functions and pathways, including cell adhesion, platelet activation, and the PI3K-Akt signaling pathway. The PPI and miRNA-mRNA networks further highlighted the significance of the key genes in PH. Drug prediction analysis revealed the potential of the key genes as therapeutic targets. The RT-PCR and western blot experiments validated the above findings.

CONCLUSION

By integrating bioinformatics and MR analysis, we found that ITGA2B and TSPAN9 have a causal relationship with PH. Our findings offer new insights into the molecular mechanism and potential treatment targets of PH, establishing a basis for future research and clinical applications.

Soybean Agglutinin Induced Apoptotic Effects by Down-Regulating ANXA2 Through FAK Pathway in IPEC-J2 Cells

Soybean agglutinin (SBA) is an anti-nutritional factor in soybean, possesses toxic effects by binding to intestinal epithelial cells, and finally interferes the digestion and absorption of nutrients in humans and animals. Annexin A2 (ANXA2) is one of the SBA-specific binding proteins in intestinal epithelial cells and participates in multiple cellular biological processes. However, whether SBA affects apoptosis through ANXA2 and its apoptosis-related pathway remains unclear. IPEC-J2 is an ideal model to study human intestinal health. Therefore, this study aims to investigate the effects of ANXA2 on SBA-induced intestinal epithelial cell apoptosis and the related pathway mechanism using IPEC-J2 as a cell model. The results showed that SBA induced the apoptosis through FAK signal pathway and decreased the gene and protein expressions of ANXA2 in IPEC-J2. The expression of ANXA2 protein had a negative correlation with the apoptosis rates, and a positive correlation with the expression of FAK protein and FAK pathway downstream proteins. In conclusion, SBA induced apoptosis of IPEC-J2 cells by downregulating the expression of ANXA2, which activated the FAK pathway. These findings highlight the toxic mechanism of SBA, which will provide basis for studying the toxicity mechanisms of other food-derived anti-nutrients and provide a new perspective for human gastrointestinal health and related cancer treatment.

Spatial Profiling Reveals Equivalence-Derived Molecular Signatures of Brain Mimicry and Adaptation in Breast Cancer Brain Metastases

Brain metastases (BrMets), common for advanced-stage breast cancer patients, are associated with poor median survival and accompanied by severe neurologic decline. Halting the progression of breast cancer brain metastases (BCBMs) may require modulation of the tumor microenvironment (TME), yet little is known about the impact of the primary breast TME on brain tropism, or how, once there, metastatic breast cancer cells coexist with brain-resident cells (e.g., neurons and glia). Traditionally, studies in this space have focused on differential expression analysis, overlooking potential insights gained from investigating genes with equivalent expression between groups. This is particularly crucial in distant metastasis, where tumor cells may co-opt the transcriptional programs of the host organ (e.g., brain) to facilitate successful seeding and outgrowth. Prior to our work, no computational framework existed to determine biologically-relevant equivalent gene expression. To resolve molecular mechanisms of BCBM enabled by metastatic cancer cells and/or resident brain cells, we leveraged Nanostring GeoMx to perform spatially-resolved transcriptomic profiling on 235 patient-derived tissue cores from BCBM (including adjacent normal brain), primary invasive breast cancers, and normal (non-cancer) brain; analyzing 18,677 RNAs in 450 areas of interest (AOIs). We introduce the "Equivalent Expression Index" a highly specific and accurate algorithm that identifies statistically significant "Equivalently-Expressed Genes". This method facilitated the identification of molecular remodeling and mimicry genes within tissue-specific TMEs. By integrating differential expression analysis with the Equivalent Expression Index, we discovered multiple novel gene signatures associated with BCBM and primary tumor brain-metastatic potential. We demonstrate that the Equivalent Expression Index is a powerful tool to uncover shared gene expression programs representing the adaptation of metastatic cells and brain-resident cells to the BCBM microenvironment.

Integrated single-cell analysis reveals heterogeneity and therapeutic insights in osteosarcoma

Osteosarcoma (OSA) is a primary bone malignancy characterized by its aggressive nature and high propensity for metastasis. Despite advancements in multimodal therapies, the clinical outcomes for OSA patients remain suboptimal, necessitating deeper molecular insights for improved therapeutic strategies. Here, we employed single-cell RNA sequencing (scRNA-seq) to elucidate the cellular heterogeneity and transcriptional dynamics of OSA tumors. Our study identified eleven distinct tumor cell subpopulations, including osteoblastic, chondroblastic, and myeloid lineages, each exhibiting unique transcriptional profiles associated with disease progression and metastasis. Epithelial-mesenchymal transition (EMT) emerged as a critical process driving aggressive phenotypes, supported by gene set enrichment analyses (GSVA) and transcription factor regulatory network analyses. Integration of copy number variation (CNV) data highlighted genomic alterations in osteoblastic and chondroblastic cells, implicating potential therapeutic targets. Furthermore, immune cell infiltration analyses revealed distinct immune profiles across OSA subtypes, correlating with tumor mutational burden (TMB) and clinical outcomes. Our findings underscore the complexity of OSA biology and provide a foundation for developing personalized treatment strategies targeting tumor heterogeneity and immune interactions.

MFAP2 induces epithelial-mesenchymal transformation of osteosarcoma cells by activating the Notch1 pathway

Background

Osteosarcoma (OS) is a malignancy originating from mesenchymal tissue. Microfibril-associated protein 2 (MFAP2) plays a crucial role in cancer, notably promoting epithelial-mesenchymal transition (EMT). However, its involvement in OS remains unexplored.

Methods

MFAP2 was silenced in U2OS cells using shRNA targeting MFAP2 (sh-MFAP2) and validated by quantitative real-time polymerase chain reaction (qRT-PCR). We extracted gene chip data of MFAP2 from multiple databases (GSE28424, GSE42572, and GSE126209). Correlation analyses between MFAP2 and the Notch1 pathway identified through the gene set variation analysis (GSVA) enrichment analysis were conducted using the Pearson correlation method. Cellular behaviors (viability, migration, and invasion) were assessed via the Cell Counting Kit-8 (CCK-8), wound healing, and Transwell assays. EMT markers (N-cadherin, vimentin, and β-catenin) and Notch1 levels were examined by western blotting and qRT-PCR. Cell morphology was observed microscopically to evaluate EMT. Finally, the role of MFAP2 in OS was validated through a xenograft tumor model.

Results

OS cell lines exhibited higher MFAP2 mRNA expression than normal osteoblasts. MFAP2 knockdown in U2OS cells significantly reduced viability, migration, and invasion, along with downregulation of N-cadherin and vimentin, as well as upregulation of β-catenin. MFAP2 significantly correlated with the Notch1 pathway in OS and its knockdown inhibited Notch1 protein expression. Furthermore, Notch1 activation reversed the inhibitory effects of MFAP2 knockdown on the malignant characteristic of U2OS cells. Additionally, MFAP2 knockdown inhibited tumor growth, expression levels of EMT markers, and Notch1 expression in OS tumor tissues.

Conclusions

Our study revealed that MFAP2 was an upstream regulator of the Notch1 signaling pathway to promote EMT in OS. These findings suggested MFAP2 as a potential OS therapy target.

Roles and inhibitors of FAK in cancer: current advances and future directions

Focal adhesion kinase (FAK) is a non-receptor tyrosine kinase that exhibits high expression in various tumors and is associated with a poor prognosis. FAK activation promotes tumor growth, invasion, metastasis, and angiogenesis via both kinase-dependent and kinase-independent pathways. Moreover, FAK is crucial for sustaining the tumor microenvironment. The inhibition of FAK impedes tumorigenesis, metastasis, and drug resistance in cancer. Therefore, developing targeted inhibitors against FAK presents a promising therapeutic strategy. To date, numerous FAK inhibitors, including IN10018, defactinib, GSK2256098, conteltinib, and APG-2449, have been developed, which have demonstrated positive anti-tumor effects in preclinical studies and are undergoing clinical trials for several types of tumors. Moreover, many novel FAK inhibitors are currently in preclinical studies to advance targeted therapy for tumors with aberrantly activated FAK. The benefits of FAK degraders, especially in terms of their scaffold function, are increasingly evident, holding promising potential for future clinical exploration and breakthroughs. This review aims to clarify FAK's role in cancer, offering a comprehensive overview of the current status and future prospects of FAK-targeted therapy and combination approaches. The goal is to provide valuable insights for advancing anti-cancer treatment strategies.

The role of Tetraspanins in digestive system tumor development: update and emerging evidence

Digestive system malignancies, including cancers of the esophagus, pancreas, stomach, liver, and colorectum, are the leading causes of cancer-related deaths worldwide due to their high morbidity and poor prognosis. The lack of effective early diagnosis methods is a significant factor contributing to the poor prognosis for these malignancies. Tetraspanins (Tspans) are a superfamily of 4-transmembrane proteins (TM4SF), classified as low-molecular-weight glycoproteins, with 33 Tspan family members identified in humans to date. They interact with other membrane proteins or TM4SF members to form a functional platform on the cytoplasmic membrane called Tspan-enriched microdomain and serve multiple functions including cell adhesion, migration, propagation and signal transduction. In this review, we summarize the various roles of Tspans in the progression of digestive system tumors and the underlying molecular mechanisms in recent years. Generally, the expression of CD9, CD151, Tspan1, Tspan5, Tspan8, Tspan12, Tspan15, and Tspan31 are upregulated, facilitating the migration and invasion of digestive system cancer cells. Conversely, Tspan7, CD82, CD63, Tspan7, and Tspan9 are downregulated, suppressing digestive system tumor cell metastasis. Furthermore, the connection between Tspans and the metastasis of malignant bone tumors is reviewed. We also summarize the potential role of Tspans as novel immunotherapy targets and as an approach to overcome drug resistance. Finally, we discuss the potential clinical value and therapeutic targets of Tspans in the treatments of digestive system malignancies and provide some guidance for future research.

Spatial Transcriptomic Profiling of Tetraspanins in Stage 4 Colon Cancer from Primary Tumor and Liver Metastasis

Stage 4 colon cancer (CC) presents a significant global health challenge due to its poor prognosis and limited treatment options. Tetraspanins, the transmembrane proteins involved in crucial cancer processes, have recently gained attention as diagnostic markers and therapeutic targets. However, their spatial expression and potential roles in stage 4 CC tissues remain unknown. Using the GeoMx digital spatial profiler, we profiled all 33 human tetraspanin genes in 48 areas within stage 4 CC tissues, segmented into immune, fibroblast, and tumor compartments. Our results unveiled diverse gene expression patterns across different primary tumor sub-regions. CD53 exhibited distinct overexpression in the immune compartment, hinting at a potential role in immune modulation. TSPAN9 was specifically overexpressed in the fibroblast compartment, suggesting involvement in tumor invasion and metastasis. CD9, CD151, TSPAN1, TSPAN3, TSPAN8, and TSPAN13 displayed specific overexpression in the tumor compartment, indicating potential roles in tumor growth. Furthermore, our differential analysis revealed significant spatial changes in tetraspanin expression between patient-matched stage 4 primary CC and metastatic liver tissues. These findings provide spatially resolved insights into the expression and potential roles of tetraspanins in stage 4 CC progression, proposing their utility as diagnostic markers and therapeutic targets. Understanding this landscape is beneficial for tailoring therapeutic strategies to specific sub-tumor regions in the context of stage 4 CC and liver metastasis.

Focal adhesion kinase (FAK): its structure, characteristics, and signaling in skeletal system

Focal adhesion kinase (FAK) is a non-receptor tyrosine kinase and distributes important regulatory functions in skeletal system. Mesenchymal stem cell (MSC) possesses significant migration and differentiation capacity, is an important source of distinctive bone cells production and a prominent bone development pathway. MSC has a wide range of applications in tissue bioengineering and regenerative medicine, and is frequently employed for hematopoietic support, immunological regulation, and defect repair, although current research is insufficient. FAK has been identified to cross-link with many other keys signaling pathways in bone biology and is considered as a fundamental "crossroad" on the signal transduction pathway and a "node" in the signal network to mediate MSC lineage development in skeletal system. In this review, we summarized the structure, characteristics, cellular signaling, and the interactions of FAK with other signaling pathways in the skeletal system. The discovery of FAK and its mediated molecules will lead to a new knowledge of bone development and bone construction as well as considerable potential for therapeutic use in the treatment of bone-related disorders such as osteoporosis, osteoarthritis, and osteosarcoma.

Identification of an EMT-related gene-based prognostic signature in osteosarcoma

BACKGROUND

The correlation between epithelial-mesenchymal transition (EMT) and osteosarcoma (OS) has been widely reported. Integration of the EMT-related genes to predict the prognosis is significant for investigating the mechanism of EMT in OS. Here, we aimed to construct a prognostic EMT-related gene signature for OS.

METHODS

Transcriptomic and survival data of OS patients were downloaded from Therapeutically Applicable Research to Generate Effective Treatments (TARGET) and Gene Expression Omnibus (GEO). We performed univariate Cox regression, least absolute shrinkage and selection operator (LASSO) regression, and stepwise multivariate Cox regression analysis to construct EMT-related gene signatures. Kaplan-Meier analysis and time-dependent receiver operating characteristic (ROC) were applied to evaluate its predictive performance. GSVA, ssGSEA, ESTIMATE, and scRNA-seq were performed to investigate the tumor microenvironment, and the correlation between IC50 of drugs and ERG score was investigated. Furthermore, Edu and transwell experiments were conducted to assess the malignancy of OS cells.

RESULTS

We constructed a novel EMT-related gene signature (including CDK3, MYC, UHRF2, STC2, COL5A2, MMD, and EHMT2) for outcome prediction of OS. According to the signature, patients stratified into high- and low-ERG-score groups exhibited significantly different prognoses. ROC curves and Kaplan-Meier analysis revealed a promising performance of the signature with external validation. GSVA, ssGSEA, ESTIMATE algorithm, and scRNA-seq excavated EMT-related pathways and suggested the correlation between ERG score and immune activation. Notably, the pivotal gene CDK3 was upregulated in OS tissue and positively related to OS cell proliferation and migration.

CONCLUSION

Our EMT-related gene signature might reference OS risk stratification and guide clinical strategies as an independent prognostic factor in OS.

LncRNA KIAA0087 suppresses the progression of osteosarcoma by mediating the SOCS1/JAK2/STAT3 signaling pathway

Long noncoding RNAs (lncRNAs), widely expressed in mammalian cells, play pivotal roles in osteosarcoma (OS) progression. Nevertheless, the detailed molecular mechanisms of lncRNA KIAA0087 in OS remain obscure. Here, the roles of KIAA0087 in OS tumorigenesis were investigated. KIAA0087 and miR-411-3p levels were detected by RT-qPCR. Malignant properties were assessed by CCK-8, colony formation, flow cytometry, wound healing, and transwell assays. SOCS1, EMT, and JAK2/STAT3 pathway-related protein levels were measured by western blotting. Direct binding between miR-411-3p and KIAA0087/SOCS1 was validated by a dual-luciferase reporter, RIP, and FISH assays. In vivo growth and lung metastasis were evaluated in nude mice. The expression levels of SOCS1, Ki-67, E-cadherin, and N-cadherin in tumor tissues were measured by immunohistochemical staining. Downregulation of KIAA0087 and SOCS1 and upregulation of miR-411-3p were found in OS tissues and cells. Low expression of KIAA0087 was associated with a poor survival rate. Forced expression of KIAA0087 or miR-411-3p inhibition repressed the growth, migration, invasion, EMT, and activation of the JAK2/STAT3 pathway and triggered apoptosis of OS cells. However, the opposite results were found with KIAA0087 knockdown or miR-411-3p overexpression. Mechanistic experiments indicated that KIAA0087 enhanced SOCS1 expression to inactivate the JAK2/STAT3 pathway by sponging miR-411-3p. Rescue experiments revealed that the antitumor effects of KIAA0087 overexpression or miR-411-3p suppression were counteracted by miR-411-3p mimics or SOCS1 inhibition, respectively. Finally, in vivo tumor growth and lung metastasis were inhibited in KIAA0087-overexpressing or miR-411-3p-inhibited OS cells. In summary, the downregulation of KIAA0087 promotes the growth, metastasis, and EMT of OS by targeting the miR-411-3p-mediated SOCS1/JAK2/STAT3 pathway.

Identifying diagnostic markers and constructing a prognostic model for small-cell lung cancer based on blood exosome-related genes and machine-learning methods

Background

Small-cell lung cancer (SCLC) usually presents as an extensive disease with a poor prognosis at the time of diagnosis. Exosomes are rich in biological information and have a powerful impact on tumor progression and metastasis. Therefore, this study aimed to screen for diagnostic markers of blood exosomes in SCLC patients and to build a prognostic model.

Methods

We identified blood exosome differentially expressed (DE) RNAs in the exoRBase cohort and identified feature RNAs by the LASSO, Random Forest, and SVM-REF three algorithms. Then, we identified DE genes (DEGs) between SCLC tissues and normal lung tissues in the GEO cohort and obtained exosome-associated DEGs (EDEGs) by intersection with exosomal DEmRNAs. Finally, we performed univariate Cox, LASSO, and multivariate Cox regression analyses on EDEGs to construct the model. We then compared the patients' overall survival (OS) between the two risk groups and assessed the independent prognostic value of the model using receiver operating characteristic (ROC) curve analysis.

Results

We identified 952 DEmRNAs, 210 DElncRNAs, and 190 DEcircRNAs in exosomes and identified 13 feature RNAs with good diagnostic value. Then, we obtained 274 EDEGs and constructed a risk model containing 7 genes (TBX21, ZFHX2, HIST2H2BE, LTBP1, SIAE, HIST1H2AL, and TSPAN9). Low-risk patients had a longer OS time than high-risk patients. The risk model can independently predict the prognosis of SCLC patients with the areas under the ROC curve (AUCs) of 0.820 at 1 year, 0.952 at 3 years, and 0.989 at 5 years.

Conclusions

We identified 13 valuable diagnostic markers in the exosomes of SCLC patients and constructed a new promising prognostic model for SCLC.

Convallatoxin suppresses osteosarcoma cell proliferation, migration, invasion, and enhances osteogenic differentiation by downregulating parathyroid hormone receptor 1 (PTHR1) expression and inactivating Wnt/β-catenin pathway

Osteosarcoma (OS) is the most common primary malignant bone tumor in children and adolescents. Convallatoxin, a natural cardiac glycoside, exhibits potent anti-tumor activities. Literature has confirmed that PTHR1 is highly expressed in OS tissues and cells and downregulation of PTHR1 could decrease the invasion and growth of OS cells and increase tumor differentiation. In addition, PTHR1 could activate Wnt signaling pathway to promote the malignant functions of OS. In the present study, MG63 and U2OS cells were treated with 0, 12.5, 25, and 50 nM convallatoxin in order to elucidate the precise function of convallatox on the malignant behaviors of OS cells. Moreover, MG63 and U2OS cells treated with convallatoxin were transfected with Ov-PTHR1 or sh-DKK1, aiming to explore whether convallatoxin impeded the malignant progression of OS by modulating PTHR1 and Wnt/β-catenin pathway. CCK-8, wound healing and transwell assays were employed to assess the proliferation, migration, and invasion of OS cells. Differentiation markers (collagen 1, osteopontin, RANKL, Runx2, osteocalcin) were measured to evaluate OS cell differentiation. Results illuminated that convallatoxin suppressed proliferation, migration, and invasion as well as promoted osteogenic differentiation of OS cells. Besides, convallatoxin inhibited PTHR1 expression and inactivated Wnt/β-catenin pathway and PTHR1 overexpression activated Wnt/β-catenin pathway. Furthermore, PTHR1 overexpression or DKK1 knockdown reversed the suppressing effects of convallatoxin on OS cell proliferation, migration, and invasion, as well as the enhancing effect of convallatoxin on OS cell osteogenic differentiation. Collectively, convallatoxin may repress the malignant progression of OS by blocking PTHR1 and Wnt/β-catenin pathway.