Syndecan Binding Protein Research Articles

Knockdown of SDCBP induces autophagy to promote cardiomyocyte growth and angiogenesis in hypoxia/reoxygenation model

ObjectiveAngina, myocardial infarction, and even mortality can result from myocardial ischemia (MI). Angiogenesis facilitates tissue repair, lessens cell damage, and ensures that ischemic tissues receive blood and oxygen. This study investigated the possible mechanism of syndecan-binding protein (SDCBP) on autophagy and assessed its impact on myocardial ischemia. MethodA cardiac hypoxia-reoxygenation (H/R) cell model was created for this investigation. Flow cytometry, the cell counting kit-8, and Western blotting were used to measure the damage to cardiomyocytes. Western blotting and immunofluorescence were used to quantify autophagy. Furthermore, assays for tube formation, migration, and Western blotting were used to assess angiogenic capacity. Additionally, the EGFR-PI3K-Akt signaling pathway's activation was found using Western blotting. ResultIn the H/R-induced cardiomyocyte model, there is a rise in the expression of SDCBP. Treatment with H/R markedly boosted apoptosis and considerably decreased cell survival. H/R induction strongly inhibits autophagy, increases P62 expression, and decreases LC3II/I expression. Moreover, H/R induction dramatically reduced the ability to form tubes, migrate, and express VEGF, all of which prevented cell angiogenesis. Furthermore, EGFR-PI3K-Akt signaling pathway expression is strongly inhibited by H/R induction. considerable reduction of H/R-induced cell damage, considerable inhibition of apoptosis, promotion autophagy and angiogenesis, and activation of the EGFR-PI3K-Akt signaling pathway are all possible with SDCBP knockdown. ConclusionTo summarize, this study demonstrates that via stimulating the EGFR-PI3K-Akt signaling pathway, SDCBP knockdown may mitigate the effects of H/R-induced cardiomyocyte death and encourage autophagy and blood vessel formation. A theoretical foundation for possible myocardial infarction treatment is thus provided.

Dexrazoxane inhibits the growth of esophageal squamous cell carcinoma by attenuating SDCBP/MDA-9/syntenin-mediated EGFR-PI3K-Akt pathway activation

Syndecan-binding protein (SDCBP) was reported to stimulate the advancement of esophageal squamous cell carcinoma (ESCC) and could potentially be a target for ESCC treatment. There is a growing corpus of research on the anti-tumor effects of iron chelators; however, very few studies have addressed the involvement of dexrazoxane in cancer. In this study, structure-based virtual screening was employed to select drugs targeting SDCBP from the Food and Drug Administration (FDA)-approved drug databases. The sepharose 4B beads pull-down assay revealed that dexrazoxane targeted SDCBP by interacting with its PDZ1 domain. Additionally, dexrazoxane inhibited ESCC cell proliferation and anchorage-independent colony formation via SDCBP. ESCC cell apoptosis and G2 phase arrest were induced as measured by the flow cytometry assay. Subsequent research revealed that dexrazoxane attenuated the binding ability between SDCBP and EGFR in an immunoprecipitation assay. Furthermore, dexrazoxane impaired EGFR membrane localization and inactivated the EGFR/PI3K/Akt pathway. In vivo, xenograft mouse experiments indicated that dexrazoxane suppressed ESCC tumor growth. These data indicate that dexrazoxane might be established as a potential anti-cancer agent in ESCC by targeting SDCBP.

SDCBP modulates tumor microenvironment, tumor progression and anti-PD1 efficacy in colorectal cancer.

Anti-programmed cell death 1 (aPD1) therapy has yielded limited success in patients with colorectal cancer (CRC). Syndecan binding protein (SDCBP), encodes a PDZ domain-containing protein that is essential for cellular processes, including cell adhesion, migration, and signal transduction. Here, we investigated the effect of SDCBP on tumor progression, immunotherapy, and the tumor microenvironment (TME) in CRC. High expression of SDCBP is associated with non-response to immunotherapy and correlated with poorer disease-free survival (DFS) in CRC patients. Inhibiting SDCBP by transfecting shRNA or using its inhibitor zinc pyrithione (ZnPT) hindered proliferation and metastasis while enhancing the efficacy of aPD1 treatment in a mouse xenograft model and liver metastasis model. The TME of CRC was significantly altered following ZnPT treatment characterized by a reduced amount of M2 macrophages and a heightened percentage of M1 macrophages. The co-culture system of CRC cells and macrophages provided evidence that SDCBP silencing promoted the repolarisation of M2 macrophages into M1. SDCBP promotes the proliferation, metastasis, and immunotherapy resistance of CRC. Thus, ZnPT represents an effective SDCBP inhibitor and exhibits considerable potential for combination with aPD1 to enhance immunotherapy efficacy.

Melanoma differentiation associated gene-9/syndecan binding protein promotes hepatocellular carcinoma.

The oncogene Melanoma differentiation associated gene-9/syndecan binding protein (MDA-9/SDCBP) is overexpressed in many cancers, promoting aggressive, metastatic disease. However, the role of MDA-9 in regulating hepatocellular carcinoma (HCC) has not been well studied. To unravel the function of MDA-9 in HCC, we generated and characterized a transgenic mouse with hepatocyte-specific overexpression of MDA-9 (Alb/MDA-9). Compared with wild-type (WT) littermates, Alb/MDA-9 mice demonstrated significantly higher incidence of N-nitrosodiethylamine/phenobarbital-induced HCC, with marked activation and infiltration of macrophages. RNA sequencing (RNA-seq) in naive WT and Alb/MDA-9 hepatocytes identified activation of signaling pathways associated with invasion, angiogenesis, and inflammation, especially NF-κB and integrin-linked kinase signaling pathways. In nonparenchymal cells purified from naive livers, single-cell RNA-seq showed activation of Kupffer cells and macrophages in Alb/MDA-9 mice versus WT mice. A robust increase in the expression of Secreted phosphoprotein 1 (Spp1/osteopontin) was observed upon overexpression of MDA-9. Inhibition of NF-κB pathway blocked MDA-9-induced Spp1 induction, and knock down of Spp1 resulted in inhibition of MDA-9-induced macrophage migration, as well as angiogenesis. Alb/MDA-9 is a mouse model with MDA-9 overexpression in any tissue type. Our findings unravel an HCC-promoting role of MDA-9 mediated by NF-κB and Spp1 and support the rationale of using MDA-9 inhibitors as a potential treatment for aggressive HCC.

Heparanase promotes malignant phenotypes of human oral squamous carcinoma cells by regulating the epithelial-mesenchymal transition-related molecules and infiltrated levels of natural killer cells

ObjectivesThe aim of the present study was to explore the functional role of heparanase (HPSE) and investigate the effect of HPSE on epithelial-mesenchymal transition (EMT) and Tumor-infiltrating activated natural killer cells in oral squamous cell carcinoma (OSCC). Materials and methodshuman oral squamous carcinoma (SCC-25) cells were transfected with HPSE-specific small interfering RNA. Cell Counting Kit-8 assay was performed to examine cell proliferation, while flow cytometry was performed to analyze the cell cycle. Scratch assay was conducted to analyze cell migration, followed by Transwell assay to determine cell invasion. Real-Time Polymerase Chain Reaction and Western-blot assays were performed to measure epithelial-mesenchymal transition protein expression. RNA Sequencing analysis and tumor-infiltrating immune cells estimation were performed to elucidate the effect of HPSE on OSCC. ResultsKnockdown of HPSE expression decreased the proliferation rate of SCC-25 cells resulting in a significant elevation in cell percentage at the Gap phase 0/Gap phase 1 phase by suppressed cell migration and invasion. The E-cadherin messenger RNA and protein expression increased while Snail and Vimentin expression decreased. RNA Sequencing analysis performed between small interfering RNA and negative control groups identified 42 differentially expressed genes, such as syndecan binding protein, RAB11A, member RAS oncogene family, and DDB1 and CUL4 associated factor 15. ConclusionsThese results indicated that knockdown of HPSE suppressed SCC-25 cell proliferation, invasion, migration, and epithelial-mesenchymal transition, possibly via syndecan binding protein and RAB11A, member RAS oncogene family. Moreover, HPSE regulates the infiltrated levels of natural killer cells activated, possibly via DDB1 and CUL4 associated factor 15.

Dual Targeting of the PDZ1 and PDZ2 Domains of MDA-9/Syntenin Inhibits Melanoma Metastasis.

Genome-wide gene expression analysis and animal modeling indicate that melanoma differentiation associated gene-9 (mda-9, Syntenin, Syndecan binding protein, referred to as MDA-9/Syntenin) positively regulates melanoma metastasis. The MDA-9/Syntenin protein contains two tandem PDZ domains serving as a nexus for interactions with multiple proteins that initiate transcription of metastasis-associated genes. Although targeting either PDZ domain abrogates signaling and prometastatic phenotypes, the integrity of both domains is critical for full biological function. Fragment-based drug discovery and NMR identified PDZ1i, an inhibitor of the PDZ1 domain that effectively blocks cancer invasion in vitro and in vivo in multiple experimental animal models. To maximize disruption of MDA-9/Syntenin signaling, an inhibitor has now been developed that simultaneously binds and blocks activity of both PDZ domains. PDZ1i was joined to the second PDZ binding peptide (TNYYFV) with a PEG linker, resulting in PDZ1i/2i (IVMT-Rx-3) that engages both PDZ domains of MDA-9/Syntenin. IVMT-Rx-3 blocks MDA-9/Syntenin interaction with Src, reduces NF-κB activation, and inhibits MMP-2/MMP-9 expression, culminating in repression of melanoma metastasis. The in vivo antimetastatic properties of IVMT-Rx-3 are enhanced when combined with an immune-checkpoint inhibitor. Collectively, our results support the feasibility of engineering MDA-9 dual-PDZ inhibitors with enhanced antimetastatic activities and applications of IVMT-Rx-3 for developing novel therapeutic strategies effectively targeting melanoma and in principle, a broad spectrum of human cancers that also overexpress MDA-9/Syntenin.

Actionable spontaneous antibody responses antagonize malignant progression in ovarian carcinoma

ObjectiveTo demonstrate that shared antibody responses in endometriosis and endometriosis-associated ovarian cancer spontaneously antagonize malignant progression and can be leveraged to develop future immunotherapies. MethodsB cells from cyopreserved clear cell ovarian carcinoma (CCC, n = 2), endometrioid ovarian carcinoma (EC, n = 2), and endometriomas (n = 2) were isolated, activated, and EBV-immortalized. Antibodies were purified from B cell supernatants and used for screening arrays containing most of the human proteome. Targets were prioritized based on accessibility (transmembrane or secreted proteins), expression in endometriosis and cancer, and concurrent IgA and IgG responses. We focused on antibodies targeting tumor-promoting syndecan binding protein (SDCBP) to demonstrate anti-tumor activity. Immunoblots and qPCR were performed to assess SDCBP expression in ovarian cancer and endometriosis cell lines and tumor samples. Recombinant IgG4 was generated using the variable heavy and light chains of dominant B cell receptors (BCRs) reacting against the extracellular domain of SDCBP, and used in in vivo studies in human CCC- and high-grade serous ovarian carcinoma (HGSOC)-bearing immunodeficient mice. ResultsNine accessible proteins detected by both IgA and IgG were identified in all samples - including SDCBP, which is expressed in ovarian carcinomas of multiple histologies. Administration of α-SDCBP IgG4 in OVCAR3 (HGSOC), TOV21G and RMG-I (CCC) tumor-bearing mice significantly decreased tumor volume compared to control irrelevant IgG4. ConclusionsSpontaneous antibody responses exert suboptimal but measurable immune pressure against malignant progression in ovarian carcinomas. Using tumor-derived antibodies for developing novel immunotherapeutics warrants further investigation.

Abstract 3394: Simultaneous targeting of the PDZ1 and PDZ2 domains of MDA-9 inhibits melanoma metastasis

Abstract Metastasis poses significant obstacles to effective therapy and drug development. Melanoma differentiation-associated gene-9/Syntenin-1/Syndecan Binding Protein (MDA-9) is a pro-metastatic gene robustly and differentially expressed in cancer cells in comparison with corresponding adjacent normal/primary cells and represents an attractive therapeutic target to inhibit cancer cell dissemination and tumor growth. MDA-9 contains two tandem PDZ domains that provide a nexus for interactions with multiple proteins that can initiate the transcription of metastasis-associated genes. The goal of this project was to evaluate the efficiency of a unique first-in-class, second-generation MDA-9 dual-PDZ targeted pharmacological inhibitor generated using a combination of a PDZ1 small molecule and a PDZ2 selective peptide. Fragment-based drug discovery and NMR identified PDZ1i, an inhibitor of the PDZ1 domain, that effectively blocks cancer invasion in vitro and in vivo in multiple experimental animal models. To maximize the disruption of MDA-9 signaling an inhibitor has now been developed that simultaneously binds and blocks the activity of both PDZ domains. PDZ1i was joined to the second PDZ binding peptide (TNYYFV) with a PEG linker, resulting in IVMT-Rx-3 that simultaneously engages both PDZ domains of MDA-9. Mechanistic studies involved a combination of molecular and cell biology approaches and included both established and early passaged patient-derived melanoma cell lines. To test the efficacy of potential combinatorial effects in vivo we used a murine syngeneic model and B16F10, an immunotherapy-resistant murine cell line. After confirming synthesis using multiple analytical methods, e.g., HPLC, LC/MS, and NMR, the dissociation constant (determined by microscale thermophoresis (MST) analysis, of the IVMT-Rx-3 recombinant MDA-9 complex was 63 +/- 11 μM. This compound is not toxic to normal melanocytes or melanoma cells, but significantly inhibits invasion in vitro in a wide range of melanomas. IVMT-Rx-3 interrupts c-Src binding to MDA-9 and downregulates NF-kB activation. Inactivation of this transcription factor causes suppression of MMP2/MMP9 and inhibits the secretion of cytokines/growth factors. These molecular changes block cellular invasiveness and facilitate immune cytotoxicity by converting an unfavorable into a favorable tumor microenvironment culminating in the repression of melanoma metastasis. In addition, the in vivo anti-metastatic properties of IVMT-Rx-3 are enhanced when combined with an immune-checkpoint inhibitor. IVMT-Rx-3 is a unique MDA-9 antagonist in terms of composition that effectively inhibits melanoma metastasis as does our small molecule PDZ1i and holds potential for developing novel therapeutic strategies effectively targeting melanoma and in principle, a broad spectrum of human cancers that also overexpress MDA-9. Citation Format: Anjan K. Pradhan, Jinkal Modi, Santanu Maji, Amit Kumar, Praveen Bhoopathi, Padmanabhan Mannangatti, Chunqing Guo, Daniel K. Afosah, Mark Mochel, Nitai D. Mukhopadhyay, John M. Kirkwood, Xiang-Yang Wang, Umesh R. Desai, Devanand Sarkar, Luni Emdad, Swadesh K. Das, Paul B. Fisher. Simultaneous targeting of the PDZ1 and PDZ2 domains of MDA-9 inhibits melanoma metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3394.

Recurrent 8q11-13 Aberrations Leading to PLAG1 Rearrangements, Including Novel Chimeras HNRNPA2B1::PLAG1 and SDCBP::PLAG1, in Lipomatous Tumors.

Structural abnormalities of chromosome bands 8q11-13, resulting in rearrangement of the pleomorphic adenoma gene 1 (PLAG1), are known to characterize lipoblastoma, a benign fat cell tumor, found mainly in children. Here, we describe 8q11-13 rearrangements and their molecular consequences on PLAG1 in 7 lipomatous tumors in adults. The patients were 5 males and 2 females between 23 and 62 years old. The tumors, namely five lipomas, one fibrolipoma and one spindle cell lipoma, were examined using G-banding with karyotyping, fluorescence in situ hybridization (FISH; three tumors), RNA sequencing, reverse transcription (RT) PCR, and Sanger sequencing analyses (two tumors). All 7 tumors had karyotypic aberrations which included rearrangements of chromosome bands 8q11-13 (the criterion for selection into this study). FISH analyses with a PLAG1 break apart probe showed abnormal hybridization signals in both interphase nuclei and on metaphase spreads indicating PLAG1 rearrangement. RNA sequencing detected fusion between exon 1 of heterogeneous nuclear ribonucleoprotein A2/B1 (HNRNPA2B1) and exon 2 or 3 of PLAG1 in a lipoma and fusion between exon 2 of syndecan binding protein (SDCBP) and exon 2 or 3 of PLAG1 in a spindle cell lipoma. The HNRNPA2B1::PLAG1 and SDCBP::PLAG1 fusion transcripts were confirmed using RT-PCR/Sanger sequencing analyses. As 8q11-13 aberrations/PLAG1-rearrangements/PLAG1-chimeras may evidently be a defining pathogenetic feature of lipogenic neoplasms of several histological types and not just lipoblastomas, we suggest that the term "8q11-13/PLAG1-rearranged lipomatous tumors" be generally adopted for this tumor subset.

SDCBP promotes pancreatic cancer progression by preventing YAP1 from β-TrCP-mediated proteasomal degradation

ObjectivePancreatic ductal adenocarcinoma (PDAC) is a highly lethal tumour with limited treatment options. Here, we identified syndecan binding protein (SDCBP), also known as syntenin1, as a novel targetable factor in...

SDCBP-AS1 destabilizes β-catenin by regulating ubiquitination and SUMOylation of hnRNP K to suppress gastric tumorigenicity and metastasis.

Gastric cancer (GC) is among the most malignant tumors, yet the pathogenesis is not fully understood, especially the lack of detailed information about the mechanisms underlying long non-coding RNA (lncRNA)-mediated post-translational modifications. Here, the molecular mechanisms and clinical significance of the novel lncRNA syndecan-binding protein 2-antisense RNA 1 (SDCBP2-AS1) in the tumorigenesis and progression of GC were investigated. The expression levels of SDCBP2-AS1 in 132 pairs of GC and adjacent normal tissues were compared, and the biological functions were assessed in vitro and in vivo. RNA pull-down and immunoprecipitation assays were conducted to clarify the interactions of SDCBP2-AS1 and heterogeneous nuclear ribonucleoprotein (hnRNP) K. RNA-sequencing, immunoprecipitation, immunofluorescence, and luciferase analyses were performed to investigate the functions of SDCBP2-AS1. SDCBP2-AS1 was significantly downregulated in GC tissues and predictive of poor patient prognosis. Silencing of SDCBP2-AS1 promoted the proliferation and migration of GC cells both in vitro and in vivo. Mechanically, SDCBP2-AS1 physically bound to hnRNP K to repress SUMOylation of hnRNP K and facilitated ubiquitination of hnRNP K and β-catenin, thereby promoting the degradation of β-catenin in the cytoplasm. Silencing of SDCBP2-AS1 caused SUMOylation of hnRNP K and stabilized β-catenin activity, which altered transcription of downstream genes, resulting in tumorigenesis and metastasis of GC. Moreover, the knockdown of hnRNP K partially abrogated the effects of SDCBP2-AS1. SDCBP2-AS1 interacts with hnRNP K to suppress tumorigenesis and metastasis of GC and regulates post-transcriptional modifications of hnRNP K to destabilize β-catenin. These findings suggest SDCBP2-AS1 as a potential target for the treatment of GC.

Abstract 920: Melanoma differentiation associated gene-9/syndecan binding protein (mda-9/sdcbp): A positive regulator of hepatocellular carcinoma

Abstract Background: Hepatocellular carcinoma (HCC) is a major clinical challenge because of increasing rates of incidence and mortality, and high resistance to standard radio- and chemotherapy. Identification of novel molecules regulating HCC facilitates development of targeted therapies having a lasting impact on HCC patient survival. The oncogene MDA-9/SDCBP promotes tumorigenesis and metastasis in many cancers. In The Cancer Genome Atlas (TCGA), 8% of HCC patients show amplification of MDA-9 gene. However, the role of MDA-9 in regulating HCC has not been well-studied. Objective: To unravel the function of MDA-9 in HCC using a transgenic mouse model with hepatocyte-specific overexpression of MDA-9 (Alb/MDA-9). Study design: Alb/MDA-9 mice were generated in B6/CBA background by using the mouse albumin promoter/enhancer element to drive human MDA-9 expression. N-nitrosodiethylamine (DEN)/phenobarbital (PB) was used for induction of HCC. Tumor immune profile was analyzed by Opal multiplex staining and flow cytometry. RNA-sequencing (RNA-seq) was performed to analyze MDA-9-mediated gene regulation. Results: At 18 months of age, none of the WT mice developed liver tumor, while one male and one female Alb/MDA-9 mice (n = 11) developed one isolated tumor each, suggesting that MDA-9 may not be a strong driver oncogene, rather it might promote HCC progression once tumor is initiated. Indeed, at 32 weeks after induction of HCC using DEN/PB, tumor burden in the livers of Alb/MDA-9 mice was significantly higher compared to WT. These tumors showed loss of hepatic architecture and hepatocyte ballooning, features of HCC. Increased staining for the proliferation marker PCNA, HCC markers AFP and cytokeratin, and angiogenesis marker CD31 in tumor sections, and significantly increased levels of serum liver enzymes, AST and ALT, were observed in Alb/MDA-9 mice vs WT. Macrophage-mediated inflammation plays a central role in HCC. Compared to WT, Alb/MDA-9 tumors showed marked infiltration of CD11b+ myeloid cells, FoxP3+ T regulatory cells and F4/80+ macrophages. RNA-seq in naïve WT and Alb/MDA-9 hepatocytes identified activation of signaling pathways associated with invasion, angiogenesis and inflammation. Conclusions: MDA-9 overexpression in hepatocytes promotes HCC by stimulating inflammation, angiogenesis and immune modulation. Studies are ongoing to obtain in-depth understanding of the molecular mechanisms by which MDA-9 exerts these pleiotropic effects. This study was supported by NIH/NCI Grant 1R01CA244993-01 (DS and PBF). Citation Format: Debashri Manna, Saranya Chidambaranathan Reghupaty, Rachel Gredler Mendoza, Maria Del Camarena, Mark A. Subler, Jennifer Koblinski, Rebecca Martin, Mikhail G. Dozmorov, Swadesh K. Das, Jolene J. Windle, Paul B. Fisher, Devanand Sarkar. Melanoma differentiation associated gene-9/syndecan binding protein (mda-9/sdcbp): A positive regulator of hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 920.

Utilization of immortalized B cells to identify SDCBP as a novel therapeutic target in ovarian carcinoma.

e14507 Background: We hypothesized that tumor-infiltrating B cells in endometriosis and endometriosis-associated ovarian cancer can be used to identify novel, targetable antigen domains to inhibit the progression of ovarian carcinomas. We aimed to identify targets that are spontaneously recognized by B-cell-derived antibodies within ovarian clear cell carcinoma (CCC), endometrioid carcinoma (EC), and endometriosis and to determine the preclinical anti-cancer efficacy of a candidate antibody that recognizes the extracellular domain of an identified target. Methods: B cells from freshly dissociated CCC (n = 2), EC (n = 2), and endometriomas (n = 2) were isolated, activated, and EBV-immortalized. Antibodies were purified from B cell supernatants and used for screening in a proteome array. Targets were prioritized based on accessibility (transmembrane or secreted proteins), expression in endometriosis and cancer, and concurrent IgA and IgG responses. Tumor-promoting syndecan binding protein (SDCBP) was identified and SDCBP-reactive B cells were FACS-sorted and subjected to single cell B cell receptor sequencing to determine the variable heavy and light chain sequences of enriched clonotypes. We then generated a recombinant IgG4 antibody targeting SDCBP with the dominant VH/VL matching sequences. Immunoblots and qPCR were performed to assess SDCBP expression in ovarian cancer cell lines and tumor samples. In vivo studies compared anti-tumor potential of the α-SDCBP IgG4 with controls using immunodeficient mouse models of human CCC and high-grade serous ovarian carcinoma (HGSOC). Results: Nine accessible proteins were detected by both IgA and IgG in all samples, including SDCBP. SDCBP is expressed in ovarian cancer cell lines and tumor samples of multiple histologies, including CCC, EC, and HGSOC. Administration of α-SDCBP IgG4 in TOV21G (CCC) tumor-bearing mice significantly decreased tumor volume compared to non-antigen-specific irrelevant IgG4 (iIgG4, p = 0.002) and vehicle (0.001), and correspondingly trended toward decreased tumor weight compared to vehicle (p = 0.06). Likewise, administration of α-SDCBP IgG4 in OVCAR3 (HGSOC) tumor-bearing mice significantly decreased tumor volume compared to iIgG4 (p = 0.03) and trended toward decreased tumor weight (p = 0.06). Conclusions: An α-SDCBP IgG4 has demonstrated anti-tumor efficacy in SDCBP+ CCC and HGSOC, and SDCBP-targeted therapy for endometriosis and associated malignant conditions, as well as HGSOC, warrants further investigation.

Expression of Exosome Biogenesis Genes Is Differentially Altered by Aging in the Mouse and in the Human Brain During Alzheimer's Disease.

Extracellular vesicles like exosomes are secreted by numerous cell types in a variety of tissues. Exosomes have been implicated in both aging and age-related disorders like Alzheimer's disease (AD). However, how aging and AD affect exosome biogenesis within and across cell types is poorly understood. Moreover, cells acquire characteristics based on tissue niche, but the impact of tissue residence on cell type exosome biogenesis is unknown. We explored the Tabula Muris Senis, Mayo RNA-seq and Rush Religious Order Study/Memory and Aging Project data sets to characterize the cell and tissue-specific effects of aging and AD on genes involved in exosome biogenesis. Specifically, we examined the age-dependent expression (age coefficient) of genes involved in exosome biogenesis (22 genes), exosome cargo (3 genes), and senescence (5 genes). Of the 131 cell populations (cell type × tissue) studied, 95 had at least 1 exosome biogenesis gene affected by age. The most common gene/transcript increased by age was charged multivesicular body protein 2A (CHMP2A) (54 cell populations). The most common gene/transcript decreased by age was syndecan-binding protein (SDCBP) (58 cell populations). The senescence-associated genes cyclin-dependent kinase 1A (CDKN1A) and CDKN2A were not related to changes in CHMP2A and SDCBP and were altered by age in fewer cell populations. Finally, individuals with AD had decreased CHMP2A and increased SDCBP expression, opposite of what is observed during mouse aging in the absence of disease. These findings indicate that exosome biogenesis gene expression is modified by age in many cell populations mostly independent of senescence, and may be further altered in AD.

Pharmacological inhibition of MDA-9/Syntenin blocks breast cancer metastasis through suppression of IL-1β

Melanoma differentiation associated gene-9 (MDA-9), Syntenin-1, or syndecan binding protein is a differentially regulated prometastatic gene with elevated expression in advanced stages of melanoma. MDA-9/Syntenin expression positively associates with advanced disease stage in multiple histologically distinct cancers and negatively correlates with patient survival and response to chemotherapy. MDA-9/Syntenin is a highly conserved PDZ-domain scaffold protein, robustly expressed in a spectrum of diverse cancer cell lines and clinical samples. PDZ domains interact with a number of proteins, many of which are critical regulators of signaling cascades in cancer. Knockdown of MDA-9/Syntenin decreases cancer cell metastasis, sensitizing these cells to radiation. Genetic silencing of MDA-9/Syntenin or treatment with a pharmacological inhibitor of the PDZ1 domain, PDZ1i, also activates the immune system to kill cancer cells. Additionally, suppression of MDA-9/Syntenin deregulates myeloid-derived suppressor cell differentiation via the STAT3/interleukin (IL)-1β pathway, which concomitantly promotes activation of cytotoxic T lymphocytes. Biologically, PDZ1i treatment decreases metastatic nodule formation in the lungs, resulting in significantly fewer invasive cancer cells. In summary, our observations indicate that MDA-9/Syntenin provides a direct therapeutic target for mitigating aggressive breast cancer and a small-molecule inhibitor, PDZ1i, provides a promising reagent for inhibiting advanced breast cancer pathogenesis.

Hepatic Autophagy Deficiency Leads to Increased Production of Extracellular Vesicles

As an evolutionarily conserved metabolic process autophagy functions in transporting intracellular components by the autophagosome to the lysosome for degradation. Extracellular vehicles (EVs) are defined as membrane-surrounded, nanometer-sized vesicles released by cells into the extracellular space in a highly regulated manner. Exosomes (40 to 160 nm in diameter) are a widely studied subclass of EVs, which are generated inside multivesicular bodies (MVBs) and released into the extracellular space when MVBs are fused with the plasma membrane. Both autophagy and EVs are related to vesicular trafficking process, and they share some common pathways. However, the relationship of EVs production and autophagy function is largely unknown. In the present study, we found an increased production of exosomes under the condition of hepatic autophagy deficiency. Transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA) showed that the average size of exosomes isolated from the serum of hepatic Atg7-deficient was around 100 nm, which was about the same size as the exosome from the Atg7-floxed mice. In addition to the commonly defined markers in hepatocyte-derived exosome, such as TSG101 and CYP2E1, exosomes produced by autophagy deficient hepatocytes also carry unique protein markers, such as Syntenin-2, which is a Syndecan-binding protein and is closely related to the formation of MVBs. Compared to those in Atg7-floxed livers, both the mRNA and protein levels of Syntenin-2 were increased in Atg7 -/- livers. Interestingly, increased expression of Syntenin-2 and increased production of exosomesin Atg7 -/- deficient mice were reversed by co-deletion of an anti-oxidative gene, Nrf2. In summary, liver-specific autophagy deficiency enhances the Nrf2-dependent expression of Syntenin-2, thereby promoting the production of exosomes, perhaps via increased activity of MVB.

Seven Novel Genes Related to Cell Proliferation and Migration of VHL-Mutated Pheochromocytoma.

Pheochromocytoma, as a neuroendocrine tumor with the highest genetic correlation in all types of tumors, has attracted extensive attention. Von Hipper Lindau (VHL) has the highest mutation frequency among the genes associated with pheochromocytoma. However, the effect of VHL on the proteome of pheochromocytoma remains to be explored. In this study, the VHL knockdown (VHL-KD) PC12 cell model was established by RNA interference (shRNA). We compared the proteomics of VHL-KD and VHL-WT PC12 cell lines. The results showed that the expression of 434 proteins (VHL shRNA/WT > 1.3) changed significantly in VHL-KD-PC12 cells. Among the 434 kinds of proteins, 83 were involved in cell proliferation, cell cycle and cell migration, and so on. More importantly, among these proteins, we found seven novel key genes, including Connective Tissue Growth Factor (CTGF), Syndecan Binding Protein (SDCBP), Cysteine Rich Protein 61 (CYR61/CCN1), Collagen Type III Alpha 1 Chain (COL3A1), Collagen Type I Alpha 1 Chain (COL1A1), Collagen Type V Alpha 2 Chain (COL5A2), and Serpin Family E Member 1 (SERPINE1), were overexpressed and simultaneously regulated cell proliferation and migration in VHL-KD PC12 cells. Furthermore, the abnormal accumulation of HIF2α caused by VHL-KD significantly increased the expression of these seven genes during hypoxia. Moreover, cell-counting, scratch, and transwell assays demonstrated that VHL-KD could promote cell proliferation and migration, and changed cell morphology. These findings indicated that inhibition of VHL expression could promote the development of pheochromocytoma by activating the expression of cell proliferation and migration associated genes.

Downregulation of SDCBP inhibits cell proliferation and induces apoptosis by regulating PI3K/AKT/mTOR pathway in gastric carcinoma.

Syndecan-binding protein (SDCBP) has been reported to critically process a core role in tumorigenesis. This study was conducted to characterize a novel regulatory network of SDCBP in gastric carcinoma (GC) cells. Our findings indicated that overexpression of SDCBP promoted the proliferation of GC cell and increased proliferating cell nuclear antigen (PCNA) expression. Moreover, the overexpression of SDCBP suppressed the apoptosis of GC cell along with a decrease of Bax/Bcl-2 ratio and induction of PI3K/AKT/mTOR activation. However, knockdown of SDCBP exhibited opposed effects on GC cells. Furthermore, silencing SDCBP significantly inhibited GC cell viability and PCNA expression accompanied with the upregulated cell apoptosis and Bax/Bcl-2 ratio, which was regulated by PI3K/AKT/mTOR signaling pathway. And it was further determined that PI3K inhibitor LY294002, AKT inhibitor Torin1, and mTOR inhibitor MK-2206 suppressed the apoptosis. In conclusion, SDCBP promotes the growth ability of GC by inducing the PCNA expression and inhibiting GC cell apoptosis via inactivation of the PI3K/AKT/mTOR pathway.

Prune-1 drives polarization of tumor-associated macrophages (TAMs) within the lung metastatic niche in triple-negative breast cancer

SummaryM2-tumor-associated macrophages (M2-TAMs) in the tumor microenvironment represent a prognostic indicator for poor outcome in triple-negative breast cancer (TNBC).Here we show that Prune-1 overexpression in human TNBC patients has positive correlation to lung metastasis and infiltrating M2-TAMs. Thus, we demonstrate that Prune-1 promotes lung metastasis in a genetically engineered mouse model of metastatic TNBC augmenting M2-polarization of TAMs within the tumor microenvironment. Thus, this occurs through TGF-β enhancement, IL-17F secretion, and extracellular vesicle protein content modulation.We also find murine inactivating gene variants in human TNBC patient cohorts that are involved in activation of the innate immune response, cell adhesion, apoptotic pathways, and DNA repair. Altogether, we indicate that the overexpression of Prune-1, IL-10, COL4A1, ILR1, and PDGFB, together with inactivating mutations of PDE9A, CD244, Sirpb1b, SV140, Iqca1, and PIP5K1B genes, might represent a route of metastatic lung dissemination that need future prognostic validations.

Downregulation of exosomal miR‑1273a increases cisplatin resistance of non‑small cell lung cancer by upregulating the expression of syndecan binding protein

Resistance to platinum-based drugs, such as cisplatin (CDDP), has been one of the major factors adversely affecting the clinical prognosis of patients with advanced non-small cell lung cancer (NSCLC). While it has been demonstrated that dysregulation of microRNAs (miRNAs) may contribute to cisplatin resistance in NSCLC, the underlying mechanisms remain largely unclear. In the present study, the effect of exosomal miR-1273a on cisplatin sensitivity of NSCLC was investigated. Microarray analysis was conducted to analyze the miRNA expression profiles in exosomes isolated from A549 cells treated with or without CDDP, and miR-1273a was found to be the most prominently downregulated miRNA in CDDP-treated exosomes. Overexpression of miR-1273a significantly increased the cytotoxicity of CDDP and induced apoptosis in A549 cells. Syndecan binding protein (SDCBP) was predicted to be a direct target of miR-1273a by bioinformatics and was found to be downregulated by miR-1273a in A549 cells. Furthermore, decreased plasma exosomal miR-1273a and increased plasma SDCBP levels were found to be associated with worse therapeutic outcomes of patients with advanced NSCLC receiving platinum-based chemotherapy. These findings suggest that miR-1273a is closely associated with the development of cisplatin resistance and may serve as a potential prognostic biomarker and therapeutic target for NSCLC.