CCL28 promotes progression of hepatocellular carcinoma through PDGFD-regulated MMP9 and VEGFA pathways.

Hepatocellular carcinoma (HCC) remains a major global health concern with limited therapeutic options and poor prognosis. Chemokines have emerged as critical regulators in the progression and metastasis of HCC. This study aims to investigate the mechanisms involved in CCL28-promoted progression of HCC and provide novel therapeutic targets for HCC treatment. Relationship between CCL28 expression and HCC progression were investigated by bioinformatic analysis and immunohistochemical staining assays. CCK-8, Transwell, and colony formation assay were conducted to explore the impact of CCL28 on the growth, migration and invasion of HCC cells. Quantitative real-time PCR and western blotting assays were performed to learn potential molecular mechanisms underlying the transformation of HCC driven by CCL28. The results showed that there was a direct link between increased CCL28 levels and the advancement of HCC, leading to a worse outcome. CCL28 significantly augmented malignant transformation of HCC cells, containing proliferation, migration, invasion, and clonogenicity, via activation of PDGFD-regulated MMP9 and VEGFA pathways. CCL28 emerges as a pivotal contributor to HCC tumorigenesis, propelling HCC development through the PDGFD signaling pathway. Our findings unveil potential therapeutic targets for HCC treatment.

The role of THBS1 and PDGFD in the immune microenvironment of Helicobacter pylori-associated gastric cancer.

BACKGROUND AND STUDY AIMS: Immunotherapy has emerged as a hot topic in cancer treatment in recent years and has also shown potential in the treatment of Helicobacter pylori-associated gastric cancer. However, there is still a need to identify potential immunotherapy targets. MATERIAL AND METHODS: We used the GSE116312 dataset of Helicobacter pylori-associated gastric cancer to identify differentially expressed genes, which were then overlapped with immune genes from the ImmPort database. The identified immune genes were used to classify gastric cancer samples and evaluate the relationship between classification and tumor mutations, as well as immune infiltration. An immune gene-based prognostic model was constructed, and the expression levels of the genes involved in constructing the model were explored in the tumor immune microenvironment. RESULTS: We successfully identified 60 immune genes and classified gastric cancer samples into two subtypes, which showed differences in prognosis, tumor mutations, immune checkpoint expression, and immune cell infiltration. Subsequently, we constructed an immune prognostic model consisting of THBS1 and PDGFD, which showed significant associations with macrophages and fibroblasts. CONCLUSION: We identified abnormal expression of THBS1 and PDGFD in cancer-associated fibroblasts (CAFs) within the tumor immune microenvironment, suggesting their potential as therapeutic targets.

Endothelial PDGF-D contributes to neurovascular protection after ischemic stroke by rescuing pericyte functions.

Ischemic stroke induces neovascularization of the injured tissue as an attempt to promote structural repair and neurological recovery. Angiogenesis is regulated by pericytes that potently react to ischemic stroke stressors, ranging from death to dysfunction. Platelet-derived growth factor (PDGF) receptor (PDGFR)ß controls pericyte survival, migration, and interaction with brain endothelial cells. PDGF-D a specific ligand of PDGFRß is expressed in the brain, yet its regulation and role in ischemic stroke pathobiology remains unexplored. Using experimental ischemic stroke mouse model, we found that PDGF-D is transiently induced in brain endothelial cells at the injury site in the subacute phase. To investigate the biological significance of PDGF-D post-ischemic stroke regulation, its subacute expression was either downregulated using siRNA or upregulated using an active recombinant form. Attenuation of PDGF-D subacute induction exacerbates neuronal loss, impairs microvascular density, alters vascular permeability, and increases microvascular stalling. Increasing PDGF-D subacute bioavailability rescues neuronal survival and improves neurological recovery. PDGF-D subacute enhanced bioavailability promotes stable neovascularization of the injured tissue and improves brain perfusion. Notably, PDGF-D enhanced bioavailability improves pericyte association with brain endothelial cells. Cell-based assays using human brain pericyte and brain endothelial cells exposed to ischemia-like conditions were applied to investigate the underlying mechanisms. PDGF-D stimulation attenuates pericyte loss and fibrotic transition, while increasing the secretion of pro-angiogenic and vascular protective factors. Moreover, PDGF-D stimulates pericyte migration required for optimal endothelial coverage and promotes angiogenesis. Our study unravels new insights into PDGF-D contribution to neurovascular protection after ischemic stroke by rescuing the functions of pericytes.

Exploring the impact of PDGFD in osteosarcoma metastasis through single-cell sequencing analysis.

PURPOSE: The overall survival rate for metastatic osteosarcoma hovers around 20%. Responses to second-line chemotherapy, targeted therapies, and immunotherapies have demonstrated limited efficacy in metastatic osteosarcoma. Our objective is to validate differentially expressed genes and signaling pathways between non-metastatic and metastatic osteosarcoma, employing single-cell RNA sequencing (scRNA-seq) and additional functional investigations. We aim to enhance comprehension of metastatic mechanisms and potentially unveil a therapeutic target. METHODS: scRNA-seq was performed on two primary osteosarcoma lesions (1 non-metastatic and 1 metastatic). Seurat package facilitated dimensionality reduction and cluster identification. Copy number variation (CNV) was predicted using InferCNV. CellChat characterized ligand-receptor-based intercellular communication networks. Differentially expressed genes underwent GO function enrichment analysis and GSEA. Validation was achieved through the GSE152048 dataset, which identified PDGFD-PDGFRB as a common ligand-receptor pair with significant contribution. Immunohistochemistry assessed PDGFD and PDGFRB expression, while multicolor immunofluorescence and flow cytometry provided insight into spatial relationships and the tumor immune microenvironment. Kaplan-Meier survival analysis compared metastasis-free survival and overall survival between high and low levels of PDGFD and PDGFRB. Manipulation of PDGFD expression in primary osteosarcoma cells examined invasion abilities and related markers. RESULTS: Ten clusters encompassing osteoblasts, osteoclasts, osteocytes, fibroblasts, pericytes, endothelial cells, myeloid cells, T cells, B cells, and proliferating cells were identified. Osteoblasts, osteoclasts, and osteocytes exhibited heightened CNV levels. Ligand-receptor-based communication networks exposed significant fibroblast crosstalk with other cell types, and the PDGF signaling pathway was activated in non-metastatic osteosarcoma primary lesion. These results were corroborated by the GSE152048 dataset, confirming the prominence of PDGFD-PDGFRB as a common ligand-receptor pair. Immunohistochemistry demonstrated considerably greater PDGFD expression in non-metastatic osteosarcoma tissues and organoids, correlating with extended metastasis-free and overall survival. PDGFRB expression showed no significant variation between non-metastatic and metastatic osteosarcoma, nor strong correlations with survival times. Multicolor immunofluorescence suggested co-localization of PDGFD with PDGFRB. Flow cytometry unveiled a highly immunosuppressive microenvironment in metastatic osteosarcoma. Manipulating PDGFD expression demonstrated altered invasive abilities and marker expressions in primary osteosarcoma cells from both non-metastatic and metastatic lesions. CONCLUSIONS: scRNA-seq illuminated the activation of the PDGF signaling pathway in primary lesion of non-metastatic osteosarcoma. PDGFD displayed an inhibitory effect on osteosarcoma metastasis, likely through the suppression of the EMT signaling pathway.

MicroRNA miR-145-5p Inhibits Cutaneous Wound Healing by Targeting PDGFD in Diabetic Foot Ulcer.

Diabetic foot ulcer (DFU) is one major, common and serious chronic complication of diabetes mellitus, which is characterized by high incidence, high risk, high burden, and high treatment difficulty and is a leading cause of disability and death in patients with diabetes. Long-term hyperglycemia can result in cellular dysfunction of fibroblasts, which play pivotal roles in wound healing. MicroRNAs (miRNAs) were reported to mediate the pathological processes of multiple diseases, including diabetic wound healing. This research aimed to investigate the functional role of miR-145-5p in high-glucose (HG)-exposed fibroblasts and in DFU mouse models. Human foreskin fibroblast cells (HFF-1) were stimulated by HG to induce cell injury. MiR-145-5p level in HG-stimulated HFF-1 cells was detected via RT-qPCR. The binding between miR-145-5p and PDGFD was validated by Luciferase reporter assay. The effects of the miR-145-5p/PDGFD axis on the viability, migration, and apoptosis of HG-exposed HFF-1 cells were determined by CCK-8, wound healing, and flow cytometry assays. DFU mouse models were subcutaneously injected at the wound edges with miR-145-5p inhibitor/mimics. Images of the wounds were captured on day 0 and 8 post-injection, and wound samples were collected after mice were sacrificed for histological analysis by H&E staining. HG decreased cell viability and increased miR-145-5p expression in HFF-1 cells in a dose- and time-dependent manner. MiR-145-5p downregulation promoted cell viability and migration and inhibited cell apoptosis of HG-stimulated HFF-1 cells, while miR-145-5p overexpression exerted an opposite effect on cell viability, migration, and apoptosis. PDGFD was a direct target gene of miR-145-5p, whose silencing reversed the influence of miR-145-5p downregulation on HG-induced cellular dysfunction of HFF-1 cells. Additionally, downregulating miR-145-5p facilitated while overexpressing miR-145-5p inhibited wound healing in DFU mouse models. MiR-145-5p level was negatively associated with PDGFD level in wound tissue samples of DFU mouse models. MiR-145-5p inhibition improves wound healing in DFU through upregulating PDGFD expression.

Positive regulatory loop of platelet-derived growth factor DD-induced STAT3 activation is associated with poor prognosis in advanced urothelial carcinoma.

Immune checkpoint inhibitor (ICI) therapy has been established for patients with advanced urothelial cancer (UC). The necessity of overcoming resistance to ICIs and identifying a predictive factor for the same has been highlighted, such as the assessment of combination therapy with other targeted drugs and the characterization of molecular signatures in the tumor microenvironment. Recently, we reported that low hemoglobin (Hb) levels and a high platelet-to-lymphocyte ratio (PLR) were significantly associated with overall survival in patients with UC who did not benefit from pembrolizumab treatment. In the present study, we identified a possible link between these unfavorable prognostic indicators and PDGF-DD-induced STAT3 activation in UC. Overlapping patients between the high STAT3- or phosphorylated STAT3-positive score group (as assessed by immunohistochemistry) and low Hb levels or high PLR group (as assessed by blood tests) showed significantly worse outcomes after pembrolizumab treatment. Additionally, using the bladder cancer JMSU1 cell line, we demonstrated a possible positive regulatory loop between autocrine/paracrine PDGF-DD and STAT3 signaling. Therefore, we suggest that STAT3 inhibition and PDGF-DD detection in the tumor microenvironment might represent a potential therapeutic strategy to overcome resistance to pembrolizumab. Moreover, this can help identify patients with UC who could benefit from combination treatment.

lncRNA PITPNA-AS1 promotes cell proliferation and metastasis in hepatocellular carcinoma by upregulating PDGFD.

Hepatocellular carcinoma (HCC) ranks high in morbidity and mortality among notorious malignancies because of the lack of effective biomarkers and treatments. LncRNA PITPNA antisense RNA 1 (PITPNA-AS1) plays an oncogenic role in HCC, yet the mechanistic basis remains unprobed. Here using Bioinformatics and PCR analyses, we validated that PITPNA-AS1 expression was significantly increased in HCC. The levels of PITPNA-AS1 in tumors were reversely correlated with the prognosis in HCC patients. Downregulation of PITPNA-AS1 inhibited malignant activities of HCC cells. Next, we elucidated that PITPNA-AS1 acts as a competing endogenous RNA (ceRNA) to sponge miR-363-5p, thereby regulating the expression of platelet-derived growth factor-D (PDGFD). Moreover, the suppression of HCC cell activities by PITPNA-AS1 downregulation can be removed by PDGFD overexpression or miR-363-5p inhibition. Collectively, our work reveals the involvement of the PITPNA-AS1/miR-363-5p/PDGFD regulatory axis in HCC progression.

Insertion/Deletion (InDel) Variants within the Sheep Fat-Deposition-Related PDGFD Gene Strongly Affect Morphological Traits.

Platelet-derived growth factor D (PDGFD) is a member of the PDGF gene family, and it plays an important role in the regulation of adipocyte development in mammals. Furthermore, genome-wide association studies (GWAS) have previously identified it as a candidate gene associated with fleece fiber variation, body size, and the fat-tail phenotype in domestic Chinese sheep. In this study, a total of 1919 indigenous Chinese sheep were genotyped to examine the association between nucleotide sequence variations in PDGFD and body morphology. Our results detected both a 14 bp insertion in intron 2 and a 13 bp deletion in intron 4 of PDGFD. Moreover, these two InDel loci had low to moderate polymorphism. Notably, the 13 bp deletion mutation of PDGFD was found to significantly affect sheep body size. Yearling rams in the Luxi black-headed sheep (LXBH) containing a heterozygous genotype (insertion/deletion, ID) were found to have larger body length, chest depth, and body weight than those with wild genotypes. Furthermore, adult ewes in the Guiqian semi-fine wool sheep (GSFW) containing a homozygous mutation (deletion/deletion, DD) were found to have smaller chest width than their peers. Moreover, yearling ewes in this group with the same homozygous mutation were found to have lower body weight, chest width, and cannon circumference compared to those of other individuals. This study demonstrates that PDGFD InDel polymorphisms have the potential to be effective molecular markers to improve morphological traits in domestic Chinese sheep.

Gene fusions in superficial mesenchymal neoplasms: Emerging entities and useful diagnostic adjuncts.

Cutaneous mesenchymal neoplasms are diagnostically challenging because of their overlapping morphology, and, often, the limited tissue in skin biopsy specimens. Molecular and cytogenetic techniques have identified characteristic gene fusions in many of these tumor types, findings that have expanded our understanding of disease pathogenesis and motivated development of useful ancillary diagnostic tools. Here, we provide an update of new findings in tumor types that can occur in the skin and superficial subcutis, including dermatofibrosarcoma protuberans, benign fibrous histiocytoma, epithelioid fibrous histiocytoma, angiomatoid fibrous histiocytoma, glomus tumor, myopericytoma/myofibroma, non-neural granular cell tumor, CIC-rearranged sarcoma, hybrid schwannoma/perineurioma, and clear cell sarcoma. We also discuss recently described and emerging tumor types that can occur in superficial locations and that harbor gene fusions, including nested glomoid neoplasm with GLI1 alterations, clear cell tumor with melanocytic differentiation and ACTIN::MITF translocation, melanocytic tumor with CRTC1::TRIM11 fusion, EWSR1::SMAD3-rearranged fibroblastic tumor, PLAG1-rearranged fibroblastic tumor, and superficial ALK-rearranged myxoid spindle cell neoplasm. When possible, we discuss how fusion events mediate the pathogenesis of these tumor types, and we also discuss the related diagnostic and therapeutic implications of these events.

PDGF-D-induced immunoproteasome activation and cell-cell interactions.

Platelet-derived growth factor-D (PDGF-D) is abundantly expressed in ocular diseases. Yet, it remains unknown whether and how PDGF-D affects ocular cells or cell-cell interactions in the eye. In this study, using single-cell RNA sequencing (scRNA-seq) and a mouse model of PDGF-D overexpression in retinal pigment epithelial (RPE) cells, we found that PDGF-D overexpression markedly upregulated the key immunoproteasome genes, leading to increased antigen processing/presentation capacity of RPE cells. Also, more than 6.5-fold ligand-receptor pairs were found in the PDGF-D overexpressing RPE-choroid tissues, suggesting markedly increased cell-cell interactions. Moreover, in the PDGF-D-overexpressing tissues, a unique cell population with a transcriptomic profile of both stromal cells and antigen-presenting RPE cells was detected, suggesting PDGF-D-induced epithelial-mesenchymal transition of RPE cells. Importantly, administration of ONX-0914, an immunoproteasome inhibitor, suppressed choroidal neovascularization (CNV) in a mouse CNV model in vivo. Together, we show that overexpression of PDGF-D increased pro-angiogenic immunoproteasome activities, and inhibiting immunoproteasome pathway may have therapeutic value for the treatment of neovascular diseases.

Combination therapy with chitosan/siRNA nanoplexes targeting PDGF-D and PDGFR-ß reveals anticancer effect in breast cancer.

BACKGROUND: Platelet derived growth factors (PDGF)-D and the expression of its receptor increase in neoplastic progression of cancer. Co-silencing of growth factor and receptor can be suggested as an important strategy for effective cancer therapy. In the present study, we hypothesized that suppression of PDGF-D signaling pathway with small interfering RNAs (siRNAs) targeting both PDGF-D and PDGF receptor (PDGFR)-ß is a promising strategy for anticancer therapy. METHODS: Chitosan nanoplexes containing dual and single siRNA were prepared at different weight ratios and controlled by gel retardation assay. Characterization, cellular uptake, gene silencing and invasion studies were performed. The effect of nanoplexes on breast tumor growth, PDGF expression and apoptosis was investigated. RESULTS: We have shown that downregulation of PDGF-D and PDGFR-ß with chitosan/siRNA nanoplex formulations reduced proliferation and invasion in breast cancer cells. In the in vivo breast tumor model, it was determined that the intratumoral administration of chitosan/siPDGF-D/siPDGFR-ß nanoplexes markedly decreased the tumor volume and PDGF-D and PDGFR-ß mRNA and protein expression levels and increased apoptosis. CONCLUSIONS: According to the results obtained, we evaluated the effect of PDGF-D and PDGFR-ß on breast tumor development and showed that RNAi-mediated inhibition of this pathway formulated with chitosan nanoplexes can be considered as a new breast cancer therapy strategy.

Chitosan Modification-Enhanced Silencing Effect of Ad5-shPDGF-D Vector in Breast Cancer Cell Line MDA-MB-231.

BACKGROUND: Gene therapeutics are being developed to treat metastatic breast tumors, which are mostly resistant to conventional therapies. Targeting platelet-derived growth factor-D (PDGF-D) is a viable approach because it is known to play roles in angiogenesis and tumor growth. The success of gene therapy is largely dependent on delivery vectors, but both viral and nonviral delivery vectors have their disadvantages. Evolving hybrid vectors are being used to overcome those disadvantages. OBJECTIVES: In this study, we aimed to prepare a recombinant adenovirus type-5 (Ad5)/chitosan hybrid vector to deliver shPDGF-D in a breast cancer cell line by the noncovalent coating of the Ad5 surface with chitosan, a natural polymer. METHODS: The Ad5/chitosan hybrid vector was prepared by the noncovalent coating of the Ad5 surface with different molecular weights (low and high) and different amounts of chitosan (12.5, 25, and 50 µg), and the effect of silencing PDGF-D was investigated in the MDA-MB-231 cell line. RESULTS: In vitro characterization studies showed that the noncovalent chitosan coating increased the size of the Ad5 particle and changed the surface charge from -16.53 mV to slightly neutral. In vitro cell culture studies also showed that the addition of chitosan with both low (73.61%) and high (65.86%) molecular weight increased the PDGF-D silencing efficiency of the Ad5 vector (42.44%) at 48 hours. While low-molecular-weight chitosan had faster effects, high-molecular-weight chitosan provided a more sustained effect in PDGF-D silencing. CONCLUSION: The results indicate that noncovalent chitosan modification may improve the therapeutic effects of the Ad5 vector, offering the potential for further in vitro and in vivo experiments.

Short variation of the sheep PDGFD gene is correlated with litter size.

Platelet-derived growth factor (PDGF) family, exert plays a key role in embryonic development, cell proliferation, cell migration, angiogenesis and reproduction. Related studies about GWAS analyses have found that PDGFD significantly affected deposition of tail fat in sheep, but there are no studies on reproduction in animals. In this study, three breed of sheep were used to find insertion/deletion (indel) fragment polymorphism of PDGFD which including Australian white (AUW) sheep (Meat type, n = 932), Guiqian semi-fine wool (GSFW) sheep (wool type, n = 60) and East Friensian milk (EFM) sheep (dairy type, n = 60). Only a 18-bp variation was polymorphic in the study AUW sheep population and the genotypes of different sheep breed are also specific. Moreover, the association analysis indicated that this variant was associated with litter size of AUW sheep in the first parity (p < 0.05). The litter size of II genotype was significantly lower than other genotypes in the first parity (p < 0.05). We also revealed that the PDGFD gene was relatively conservative in eight species, PDGFD mRNA expression in 832 sheep samples implying this gene was related to reproduction traits. Hence, these finding demonstrated the one-cause multipotency of PDGFD gene. Collectively, these results suggest that this indel can be used as an effective marker for sheep breeding.

PDGFD switches on stem cell endothelial commitment.

The critical factors regulating stem cell endothelial commitment and renewal remain not well understood. Here, using loss- and gain-of-function assays together with bioinformatic analysis and multiple model systems, we show that PDGFD is an essential factor that switches on endothelial commitment of embryonic stem cells (ESCs). PDGFD genetic deletion or knockdown inhibits ESC differentiation into EC lineage and increases ESC self-renewal, and PDGFD overexpression activates ESC differentiation towards ECs. RNA sequencing reveals a critical requirement of PDGFD for the expression of vascular-differentiation related genes in ESCs. Importantly, PDGFD genetic deletion or knockdown increases ESC self-renewal and decreases blood vessel densities in both embryonic and neonatal mice and in teratomas. Mechanistically, we reveal that PDGFD fulfills this function via the MAPK/ERK pathway. Our findings provide new insight of PDGFD as a novel regulator of ESC fate determination, and suggest therapeutic implications of modulating PDGFD activity in stem cell therapy.

Corrigendum: Platelet-Derived Growth Factor-D Activates Complement System to Propagate Macrophage Polarization and Neovascularization.

[This corrects the article DOI: 10.3389/fcell.2021.686886.].

PDGF-D-PDGFRß signaling enhances IL-15-mediated human natural killer cell survival.

The axis of platelet-derived growth factor (PDGF) and PDGF receptor-beta (PDGFRß) plays prominent roles in cell growth and motility. In addition, PDGF-D enhances human natural killer (NK) cell effector functions when binding to the NKp44 receptor. Here, we report an additional but previously unknown role of PDGF-D, whereby it mediates interleukin-15 (IL-15)-induced human NK cell survival but not effector functions via its binding to PDGFRß but independent of its binding to NKp44. Resting NK cells express no PDGFRß and only a low level of PDGF-D, but both are significantly up-regulated by IL-15, via the nuclear factor κB signaling pathway, to promote cell survival in an autocrine manner. Both ectopic and IL-15-induced expression of PDGFRß improves NK cell survival in response to treatment with PDGF-D. Our results suggest that the PDGF-D-PDGFRß signaling pathway is a mechanism by which IL-15 selectively regulates the survival of human NK cells without modulating their effector functions.

Dermatofibrosarcoma protuberans with platelet-derived growth factor-D rearrangement; two cases with morphologically distinct presentations.

Dermatofibrosarcoma protuberans (DFSP) is a mesenchymal neoplasm that is usually located in the dermis or subcutis and is locally aggressive. Rarely, these lesions may undergo fibrosarcomatous transformation, which is thought to increase their metastatic potential. DFSP is classically associated with a 17;22 translocation (or ring chromosome thereof) resulting in fusion of the COL1A1 and PDGFB genes. However, variant fusions involving PDGFD have been recently reported. Herein, we present two morphologically diverse cases of DFSP with PDGFD rearrangement. Case 1 is a 68-year-old female with a left dorsal foot lesion. Morphologically, the lesion is unusual as it is a well-circumscribed, hypercellular, subcutaneous nodule with uniform CD34-positive spindle cells arranged in a herringbone pattern without storiform arrangement or "honeycombing" fat entrapment. It was diagnosed as pure fibrosarcomatous DFSP. Case 2 is a 37-year-old male with a right supra-auricular lesion. Morphologically, the lesion displays classic DFSP features including bland CD34-positive spindle cells with storiform growth, fat entrapment, and infiltrative borders. Both lesions were negative for COL1A1-PDGFB fusion but positive for PDGFD rearrangement by fluorescence in situ hybridization (FISH) analysis. FISH testing for PDGFD rearrangement should be performed in cases where there is a high suspicion for DFSP but initial studies for COL1A1-PDGFB are negative.

Downregulation of PDGF-D Inhibits Proliferation and Invasion in Breast Cancer MDA-MB-231 Cells.

BACKGROUND: The platelet derived growth factor-D (PDGF-D) plays an important role in breast tumor aggressiveness. However, limited study has investigated the effect of silencing PDGF-D on the biological function of breast cancer. The purpose of this study is to clarify the potential value of PDGF-D as a target for breast cancer treatment. METHODS: Reverse transcription-polymerase chain reaction and western blot were used to detect PDGF-D expression in 5 different breast cancer cells. The lentiviral vector was usd to silence PDGF-D in MDA-MB-231 cells. Then, Methyl Thiazolyl Tetrazolium was used to detect cell viability, 5-Ethynyl-2'- deoxyuridine and a soft agar assay were used to detect cell proliferation and clonality. Additionally, cell apoptosis after PDGF-D knockdown was measured by Annexin V/ Prodium Iodide staining, and cell migration was detected by trans-well assay. Survival rate and tumor size were measured by nude mice transplantation. RESULTS: The MDA-MB-231 and SK-BR-3 cell lines showed higher PDGF-D expression than the MCF7 cell lines (P<.05). After the PDGF-D gene was silenced, the growth and colony forming abilitys ignificantly decreased (P<.05) together with the induction of apoptosis in MDA-MB-231 cells (P<.05). Moreover, MDA-MB-231 cells with PDGF-D silencing showed significantly diminished aggressive migration and invasion potential compared to other cells (P<.05). In vivo experiments also indicated that PDGF-D silencing inhibited tumor growth and improved the survival rate of tumor-bearing mice. CONCLUSION: Downregulation of PDGF-D had dramatic effects on breast cancer cell proliferation, apoptosis and migration, which indicates that it plays an important role in breast cancer development and progression.

The HIF1α-PDGFD-PDGFRα axis controls glioblastoma growth at normoxia/mild-hypoxia and confers sensitivity to targeted therapy by echinomycin.

BACKGROUND: Glioblastoma multiforme (GBM), a lethal brain tumor, remains the most daunting challenge in cancer therapy. Overexpression and constitutive activation of PDGFs and PDGFRα are observed in most GBM; however, available inhibitors targeting isolated signaling pathways are minimally effective. Therefore, better understanding of crucial mechanisms underlying GBM is needed for developing more effective targeted therapies. METHODS: Target genes controlled by HIF1α in GBM were identified by analysis of TCGA database and by RNA-sequencing of GBM cells with HIF1α knockout by sgRNA-Cas9 method. Functional roles of HIF1α, PDGFs and PDGFRs were elucidated by loss- or gain-of-function assays or chemical inhibitors, and compared in response to oxygen tension. Pharmacological efficacy and gene expression in mice with intracranial xenografts of primary GBM were analyzed by bioluminescence imaging and immunofluorescence. RESULTS: HIF1α binds the PDGFD proximal promoter and PDGFRA intron enhancers in GBM cells under normoxia or mild-hypoxia to induce their expression and maintain constitutive activation of AKT signaling, which in turn increases HIF1α protein level and activity. Paradoxically, severe hypoxia abrogates PDGFRα expression despite enhancing HIF1α accumulation and corresponding PDGF-D expression. Knockout of HIF1A, PDGFD or PDGFRA in U251 cells inhibits cell growth and invasion in vitro and eradicates tumor growth in vivo. HIF1A knockdown in primary GBM extends survival of xenograft mice, whereas PDGFD overexpression in GL261 shortens survival. HIF1α inhibitor Echinomycin induces GBM cell apoptosis and effectively inhibits growth of GBM in vivo by simultaneously targeting HIF1α-PDGFD/PDGFRα-AKT feedforward pathway. CONCLUSIONS: HIF1α orchestrates expression of PDGF-D and PDGFRα for constitutive activation of AKT pathway and is crucial for GBM malignancy. Therefore, therapies targeting HIF1α should provide an effective treatment for GBM.

Novel TNC-PDGFD fusion in fibrosarcomatous dermatofibrosarcoma protuberans: a case report.

BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is a superficial fibroblastic tumor characterized by high rate of local recurrence and low metastatic potential. Fibrosarcomatous transformation can rarely arise in DFSP either de novo or as recurrent, which represents a form of tumor progression and carries an increased risk of metastasis over classic DFSP. Cytogenetically, DFSP is characterized by a recurrent unbalanced chromosome translocation t (17;22)(q22;q13), leading to the formation of COL1A1-PDGFB fusion transcript that is present in more than 90% of cases. Alternative fusions involving the PDGFD with partners of COL6A3 or EMILIN2 have recently been documented in less than 2% of cases. Herein, we report a DFSP with fibrosarcomtous morphology harboring a novel TNC-PDGFD fusion. CASE PRESENTATION: A 54-year-old female presented with a slowly growing mass in the right thigh. Excision demonstrated a 2-cm ovoid, well-circumscribed, gray-white, mass. Microscopic examination revealed a partially encapsulated subcutaneous nodule without dermal connection. The neoplasm was composed of cellular and fairly uniform spindle cells with brisk mitoses, arranged in elongated fascicles and herringbone patterns, with focal collagenized stroma. The neoplastic cells were positive for CD34 and smooth muscle actin. Fluorescence in-situ hybridization analyses showed negative for COL1A1-PDGFB fusion as well as NTRK1/2/3 rearrangements. A subsequent RNA sequencing detected an in-frame fusion between exon 15 of TNC and exon 6 of PDGFD. This fusion was further confirmed by nested reverse transcription polymerase chain reaction amplification followed by Sanger sequencing. A diagnosis of fibrosarcomatous DFSP was rendered and the patient was in good status at a follow-up of 12 months after the operation. CONCLUSIONS: We report a fibrosarcomatous DFSP with novel TNC-PDGFD fusion, which adds to the pathologic and genetic spectrum of PDGFD-rearranged DFSP.