Diverse roles of tumor-stromal PDGFB-to-PDGFRβ signaling in breast cancer growth and metastasis

Targeting S100A8/A9-NCF1 axis in tumor microenvironment to prevent tumor metastasis by self-assembled peptide nanofibers

The immunosuppressive microenvironment plays a crucial role in driving and accelerating tumor metastasis. S100A8/A9, produced by myeloid-derived suppressor cells, is a potential therapeutic target for metastatic cancer due to its role in promoting premetastatic niche formation. Previous studies have revealed that the S100A9-targeted peptide (H6, MEWSLEKGYTIK) fused to the Fc region of mouse IgG2b antibodies exhibits antitumor effects; however, the mechanism remains unclear. Here, dual-function peptide nanofibers (H6-Q11) were constructed, consisting of peptide H6 and self-assembly peptide (Q11, QQKFQFQFEQQ), which achieved high avidity for S100A9. In vivo studies showed that H6-Q11 nanofibers significantly prolonged lung retention and inhibited pulmonary metastasis from melanoma and breast cancer without obvious toxicity. Immunological analyses indicated that treatment with H6-Q11 nanofibers decreased the infiltration of immunosuppressive cells while promoting the recruitment of immune effector cells to the lungs, potentially correlated with disturbances of S100A8/A9-NCF1 signaling in the tumor microenvironment. Our findings support a potential clinical application of S100A9-targeted peptide nanofibers as candidate nanomedicine for inhibiting tumor metastasis.

Platelet-derived growth factor subunit B overexpression promotes lung cancer tumor growth and metastasis: The role of glucose metabolism

Objective

Lung cancer represents a formidable global health challenge due to its substantial prevalence and mortality rates. Metabolic reprogramming, especially the transition to aerobic glycolysis, plays a pivotal role in the progression of lung cancer by sustaining the energy demands for rapid tumor proliferation. The prominent involvement of platelet-derived growth factor subunit B (PDGFB) in promoting the growth and metastasis of lung cancer through specific signaling cascades is well established in. Nonetheless, further research is imperative to elucidate the intricate regulatory mechanisms of PDGFB in glucose metabolism and its implications for the advancement of lung cancer. Our study is dedicated to exploring the effect of PDGFB on lung cancer by modulating glucose metabolism.

Material and Methods

First, we determined the expression patterns of PDGFB in various lung cancer cell lines (A549, H460, HCC827, and H1975) using quantitative real-time polymerase chain reaction and Western blot analyses. We measured the expression levels of PDGFB and Ki-67 in tumor tissues from lung cancer patients through immunohistochemistry. We then transfected lung cancer cells with a PDGFB overexpression (PDGFB OE) plasmid. The effects of PDGFB OE and galactose + PDGFB OE co-treatment on cell migration and invasion characteristics were assessed using wound healing and Transwell assays. The impact of PDGFB OE and galactose + PDGFB OE co-treatment on the proliferation capacity of lung cancer cells was evaluated through colony formation and 5-ethynyl-2'-deoxyuridine staining assays. We also measured the effects of PDGFB OE on mitochondrial function and glycolytic capacity in lung cancer cells using extracellular acidification rate assay (ECAR) measurement methods.

Results

Elevated levels of PDGFB expression were markedly detected in various lung cancer cell lines, notably A549 and H460 (P < 0.001). This observation was validated by the analysis of tumor samples from patients with lung cancer who exhibited heightened PDGFB expression in tumor tissues (P < 0.001). Moreover, an association was found between increased levels of Ki67 expression and elevated PDGFB expression (P < 0.001). The upregulation of PDGFB was linked to heightened migratory (P < 0.001), invasive (P < 0.001), and proliferative (P < 0.001) capacities of the cells. Furthermore, an elevation in lactate levels and ECAR (P < 0.001) was noted in the PDGFB OE group, along with increased levels of glycolysis-related regulatory proteins. The inhibition of aerobic glycolysis with galactose effectively mitigated the PDGFB-induced enhancement of lung cancer cell proliferation and migration.

Conclusion

By affecting glucose metabolism, PDGFB drives the growth and metastasis of lung cancer, underscoring its potential as a promising therapeutic target for the management of this complex disease.

Pan-Cancer Analysis of the Prognostic and Immunotherapeutic Value of PDGFB

Introduction

Cancer is a widespread epidemic that affects millions of individuals across the world. Identifying novel cancer targets is crucial to developing more effective cancer treatments. Platelet-derived growth factor-B (PDGFB) plays a critical role in various tumor processes, including angiogenesis and lymphatic metastasis. However, there is a lack of research on the role of PDGFB in these processes.

Methods

To address this issue, we conducted a comprehensive analysis utilizing multiple online databases to investigate the expression, prognostic, tumor stemness, and immunological effect of PDGFB. In addition, clinical samples were validated using immunohistochemistry.

Results

Our findings revealed that PDGFB was highly expressed in a diverse range of cancer types, and its expression and genetic modifications were significantly associated with clinical outcomes in certain tumors. In general, high expression of PDGFB in tumors is associated with poor prognosis. Surprisingly, PDGFB was found to be highly expressed in renal clear cell carcinoma but was associated with good prognosis. In contrast, PDGFB was low expressed in lung carcinoma, but its expression was found to improve patient survival. These findings demonstrate the complex role of PDGFB in different cancer types. The study also demonstrated that PDGFB was linked to RNA and DNA stemness in 15 and 36 tumor types, respectively, and had a positive association with tumor lymphocyte infiltration. Notably, PDGFB was found to be associated with immune modulators. PDGFB, which is involved in various immune responses, influences the malignant characteristics of various cancer types and controls immune cell infiltration. We confirmed that PDGFB positively correlated with CD8 and PDL1 expression in lower grade glioma.

Conclusion

This study concludes that PDGFB may serve as a potential prognostic marker and a potential targetable pathway in cancer immunotherapy. Overall, the study sheds new light on the role of PDGFB in cancer and highlights its potential clinical significance.

Activation of platelet-derived growth factor receptors regulate connective tissue growth factor protein levels via the AKT pathway in malignant mesothelioma cells

The incidence of malignant mesothelioma (MM), a disease linked to refractory asbestos exposure, continues to increase globally and remains largely resistant to various treatments. Our previous studies have identified a strong correlation between connective tissue growth factor (CTGF) protein expression and MM malignancy, underscoring the importance of understanding CTGF regulation in MM cells. In this study, we demonstrate for the first time that stimulation with platelet-derived growth factor receptor (PDGFR) ligand, PDGF-BB, increases CTGF protein expression levels without affecting CTGF mRNA levels. Inhibition of PDGFR resulted in a reduction of CTGF protein expression, indicating that PDGFR activation is essential in regulating CTGF protein expression in MM cells. PDGF-BB also activated the protein kinase B (AKT) pathway, and inhibition of AKT phosphorylation abolished the PDGFR-induced CTGF protein expression, suggesting that PDGFR acts upstream of CTGF via the AKT pathway. This reinforces the role of CTGF protein as a key regulator of MM malignancy. Additionally, PDGFR activation led to the phosphorylation of mTOR and 4E-BP1, critical regulators of protein synthesis downstream of AKT, suggesting that PDGFR controls CTGF protein expression through the regulation of CTGF mRNA translation.

Targeting Fibroblast-Endothelial Interactions in LAM Pathogenesis: 3D Spheroid and Spatial Transcriptomic Insights for Therapeutic Innovation

Lymphangioleiomyomatosis (LAM) is a progressive lung disease with limited treatments, largely due to an incomplete understanding of its pathogenesis. Lymphatic endothelial cells (LECs) invade LAM cell clusters, which include HMB-45-positive epithelioid cells and smooth muscle α-actin-expressing LAM-associated fibroblasts (LAMFs). Recent evidence shows that LAMFs resemble cancer-associated fibroblasts, with LAMF-LEC interactions contributing to disease progression. To explore these mechanisms, we used spatial transcriptomics on LAM lung tissues and identified a gene cluster enriched in kinase signaling pathways linked to myofibroblasts and co-expressed with LEC markers. Kinase arrays revealed elevated PDGFR and FGFR in LAMFs. Using a 3D co-culture spheroid model of primary LAMFs and LECs, we observed increased invasion in LAMF-LEC spheroids compared to non-LAM fibroblasts. Treatment with sorafenib, a multikinase inhibitor, significantly reduced invasion, outperforming Rapamycin. We also confirmed TSC2-null AML cells as key VEGF-A secretors, which was suppressed by sorafenib in both AML cells and LAMFs. These findings highlight VEGF-A and bFGF as potential therapeutic targets and suggest multikinase inhibition as a promising strategy for LAM.

Integrated meta-analyses of genome-wide effects of PM2.5 in human cells identifies widespread dysregulation of genes and pathways associated with cancer progression and patient survival

Epidemiological studies have consistently shown a positive association between exposure to ambient PM2.5, a major component of air pollution, and various types of cancer. Previous biological research has primarily focused on the association between PM2.5 and lung cancer, with limited investigation into other cancer types. In this study, we conducted a meta-analysis on multiple PM2.5-treated normal human cell lines to identify potential molecular targets and pathways of PM2.5. Our analysis revealed 310 common differentially expressed genes (DEGs) that exhibited significant dysregulation upon exposure to PM2.5. These dysregulated genes covered a diverse range of functional categories, including oncogenes, tumor suppressor genes, and immune-related genes, which collectively contribute to PM2.5-induced carcinogenesis. Pathway enrichment analysis revealed the up-regulation of pathways associated with HIF-1, VEGF, and MAPK signalling, all of which have been implicated in various cancers. Induction in the levels of HIF pathway genes (HIF1⍺, HIF2⍺, VEGFA, BNIP3, EPO and PGK1) upon PM2.5 treatment was also confirmed by qRT-PCR. Furthermore, the construction of a protein-protein interaction (PPI) network unveiled hub genes, such as NQO1 and PDGFRB, that are known to be dysregulated and significantly correlated with overall survival in lung and breast cancer patients, suggesting their potential clinical significance. This study provides a deep insight into how PM2.5-mediated dysregulation of oncogenes or tumor suppressor genes across various human tissues may play an important role in PM2.5-induced carcinogenesis. Further exploration of these dysregulated molecular targets may enhance our understanding of the biological effects of PM2.5 and facilitate the development of preventive strategies and targeted therapies for PM2.5-associated cancers.

Identification of New Chemoresistance-Associated Genes in Triple-Negative Breast Cancer by Single-Cell Transcriptomic Analysis

Triple-negative breast cancer (TNBC) is a particularly aggressive mammary neoplasia with a high fatality rate, mainly because of the development of resistance to administered chemotherapy, the standard treatment for this disease. In this study, we employ both bulk RNA-sequencing and single-cell RNA-sequencing (scRNA-seq) to investigate the transcriptional landscape of TNBC cells cultured in two-dimensional monolayers or three-dimensional spheroids, before and after developing resistance to the chemotherapeutic agents paclitaxel and doxorubicin. Our findings reveal significant transcriptional heterogeneity within the TNBC cell populations, with the scRNA-seq identifying rare subsets of cells that express resistance-associated genes not detected by the bulk RNA-seq. Furthermore, we observe a partial shift towards a highly mesenchymal phenotype in chemoresistant cells, suggesting the epithelial-to-mesenchymal transition (EMT) as a prevalent mechanism of resistance in subgroups of these cells. These insights highlight potential therapeutic targets, such as the PDGF signaling pathway mediating EMT, which could be exploited in this setting. Our study underscores the importance of single-cell approaches in understanding tumor heterogeneity and developing more effective, personalized treatment strategies to overcome chemoresistance in TNBC.

Cancer-Associated Fibroblasts Promote Lymphatic Metastasis in Cholangiocarcinoma via the PDGF-BB/PDGFR-β Mediated Paracrine Signaling Network

Patients with cholangiocarcinoma (CCA) with lymph node metastasis (LNM) have the worst prognosis, even after complete resection; however, the underlying mechanism remains unclear. Here, we established CAF-derived PDGF-BB as a regulator of LMN in CCA. Proteomics analysis revealed upregulation of PDGF-BB in CAFs derived from patients with CCA with LMN (LN+CAFs). Clinically, the expression of CAF-PDGF-BB correlated with poor prognosis and increased LMN in patients with CCA, while CAF-secreted PDGF-BB enhanced lymphatic endothelial cell (LEC)-mediated lymphangiogenesis and promoted the trans-LEC migration ability of tumor cells. Co-injection of LN+CAFs and cancer cells increased tumor growth and LMN in vivo. Mechanistically, CAF-derived PDGF-BB activated its receptor PDGFR-β and its downstream ERK1/2-JNK signaling pathways in LECs to promote lymphoangiogenesis, while it also upregulated the PDGFR-β-GSK-P65-mediated tumor cell migration. Finally, targeting PDGF-BB/PDGFR-β or the GSK-P65 signaling axis prohibited CAF-mediated popliteal lymphatic metastasis (PLM) in vivo. Overall, our findings revealed that CAFs promote tumor growth and LMN via a paracrine network, identifying a promising therapeutic target for patients with advanced CCA.

Integrated analysis of canine soft tissue sarcomas identifies recurrent mutations in TP53, KMT genes and PDGFB fusions

Soft tissue sarcomas (STS) are a heterogenous group of mesenchymal tumors representing over 50 distinct types with overlapping histological features and non-specific anatomical locations. Currently, localized sarcomas are treated with surgery + / -  radiation in both humans and dogs with few molecularly targeted therapeutic options. However, to improve precision-based cancer therapy through trials in pet dogs with naturally occurring STS tumors, knowledge of genomic profiling and molecular drivers in both species is essential. To this purpose, we sought to characterize the transcriptomic and genomic mutation profiles of canine STS subtypes (fibrosarcoma, undifferentiated pleomorphic sarcoma, and peripheral nerve sheath tumors), by leveraging RNAseq, whole exome sequencing, immunohistochemistry, and drug assays. The most common driver mutations were in cell cycle/DNA repair (31%, TP53-21%) and chromatin organization/binding (41%, KMT2D-21%) genes. Similar to a subset of human sarcomas, we identified fusion transcripts of platelet derived growth factor B and collagen genes that predict sensitivity to PDGFR inhibitors. Transcriptomic profiling grouped these canine STS tumors into 4 clusters, one PNST group (H1), and 3 FSA groups selectively enriched for extracellular matrix interactions and PDFGB fusions (H2), homeobox transcription factors (H3), and elevated T-cell infiltration (H4). This multi-omics approach provides insights into canine STS sub-types at a molecular level for comparison to their human counterparts, to improve diagnosis, and may provide additional targets for chemo- and immuno-therapy.

Gallium-68-Labeled ZPDGFRβ Affibody: A Potential PET Probe for Platelet-Derived Growth Factor Receptor β-Expressing Carcinomas

Platelet-derived growth factor receptor β (PDGFRβ) has been demonstrated to be an effective biomarker for a variety of malignant cancers, and affibody-based PDGFRβ molecules have potential as positron emission tomography (PET) tracers for the diagnosis of cancers. Based on previous pharmacokinetics studies, short-lived positron emission radionuclides, such as fluorine-18 and gallium-68, would be more suitable for affibody-based PET imaging. Thus, in the present study, we prepared a gallium-68-labeled PDGFRβ-targeting dimeric affibody conjugate and evaluated its capability for visualizing malignant tumors by micro-PET/computed tomography (CT) imaging. The PDGFRβ-targeting Z_PDGFRβ affibody was conjugated with the p-NCS-Bn-DOTA macrocyclic ligand and radiolabeled with gallium-68 to generate the ⁶⁸Ga-DOTA-Z_PDGFRβ PET probe . Then, several types of malignant carcinoma cells (U-87 MG, LS 174T, A549, H1688, and H446) were used to evaluate the targeted cellular binding capability of the PET probe through in vitro/in vivo cellular assays and whole-body imaging by micro-PET/CT. The ⁶⁸Ga-DOTA-Z_PDGFRβ was successfully prepared with a radiochemical yield of 93% and exhibited ideal stability for up to 4 h at room temperature in vitro. This radioactive conjugate demonstrated specific binding ability with PDGFRβ-expressing U-87 MG cells, which was suppressed by PDGFRβ ligands. The biodistribution of ⁶⁸Ga-DOTA-Z_PDGFRβ indicated fast liver clearance and a kidney-bladder excretion route. The U-87 MG xenografted tumor was clearly visualized with ⁶⁸Ga-DOTA-Z_PDGFRβ at 1 h postinjection using micro-PET/CT imaging. ⁶⁸Ga-DOTA-Z_PDGFRβ is a potential radiopharmaceutical for the diagnosis of PDGFRβ-expressing tumors.

Integrated analysis of canine soft tissue sarcomas identifies recurrent mutations in TP53, KMT genes and PDGFB fusions

Canine soft tissue sarcomas (STS) are a heterogenous group of malignant tumors arising from mesenchymal cells of soft tissues. This simplified collective of tumors most commonly arise from subcutaneous tissues, are treated similar clinically, and conventionally exclude other sarcomas with more definitive anatomical, histological, or biological features. Histologically, canine STS sub-types are difficult to discern at the light microscopic level due to their overlapping features. Thus, genomic, and transcriptomic profiling of canine STS may prove valuable in differentiating the diverse sub-types of mesenchymal neoplasms within this group. To this purpose we sought to characterize the transcript expression and genomic mutation profiles of canine STS. To delineate transcriptomic sub-types, hierarchical clustering was used to identify 4 groups with district expression profiles. Using the RNAseq data, we identified three samples carrying driver fusions of platelet derived growth factor B ( PDGFB ) and collagen genes. Sensitivity to imatinib was evaluated in a canine STS cell line also bearing a PDGFB fusion. Using whole exome sequencing, recurrent driver variants were identified in the cancer genes KMT2D (21% of the samples) and TP53 (21%) along with copy number losses of RB1 and CDKN2A. Gene amplifications and resulting transcript increases were identified in genes on chromosomes 13, 14, and 36. A subset of STS was identified with high T-cell infiltration. This multi-omics approach has defined canine STS sub-types at a molecular level for comparison to their human counterparts, to improve diagnosis, and may provide additional targets for therapy.