Inhibition of bone morphogenetic protein signaling reduces viability, growth and migratory potential of non-small cell lung carcinoma cells

RGMb impacts partial epithelial-mesenchymal transition and BMP2-Induced ID mRNA expression independent of PD-L2 in nonsmall cell lung cancer cells

PD-1/PD-ligand-axis immunotherapy-mediated activation of T-cells for cancer cell elimination is a promising treatment of nonsmall cell lung cancer (NSCLC). However, the effect of immunotherapy on intracellular signaling pathways in cancer cells still needs further delineation. Repulsive Guidance Molecule b (RGMb), a regulator of Bone Morphogenetic Proteins (BMPs) signaling, interacts with the PD-ligand, PD-L2, at cancer cell membranes. Accordingly, a clarification of the functions of RGMb and its relation to PD-L2 might provide insight into NSCLC cell signaling responses to PD-1/PD-ligand-axis immunotherapy. In this study, the functions of RGMb and PD-L2 were examined using the two NSCLC cell lines HCC827 and A549. CRISPR/Cas9 was used to decrease the expression of RGMb and PD-L2, while lentiviral vectors were used to increase their expression. Downstream effects were examined by RT-qPCR and immunoassays. Ectopic expression of RGMb impacted BMP2-induced expression of ID1 and ID2 messenger RNA (mRNA) independently of PD-L2, while RGMb depletion by CRISPR/Cas9 did not affect the BMP2-mediated induction of ID1, ID2, and ID3 mRNA. However, depletion of RGMb resulted in a partial epithelial-mesenchymal transition (EMT) gene expression profile in HCC827 cells, which was not mimicked by PD-L2 depletion. The results show that RGMb is a coregulator of BMP signaling and hence, ID mRNA expression and that RGMb can control the EMT balance in NSCLC cells. However, RGMb appears to exert these functions independently of PD-L2, and accordingly, the PD-1/PD-ligand axis for immune surveillance in NSCLC cells.

BMP4 Regulates EMT to be Involved in non-Syndromic Cleft lip With or Without Palate

OBJECTIVE

In the previous study, we identified bone morphogenetic protein 4 (BMP4) responsible for non-syndromic cleft lip with or without cleft palate (NSCL/P). We aimed to elucidate the effects and mechanisms of BMP4 on epithelial-mesenchymal transition (EMT) through Smad1 signaling pathway to be involved in NSCL/P.

METHODS

The human oral epidermoid carcinoma cells (KBs) were transfected with plasmids or small interfering RNA (siRNA) to build the models. The migration of the cells was evaluated by transwell assay. Western blotting and quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) were used to detect the expressions of BMP4, E-cadherin, N-cadherin, EMT-related transcription factors snal1 and snal2, matrix metalloproteinase 2 (MMP2), MMP9, Smad1, and phosphorylated Smad1.

RESULTS

In the overexpression group, the migration number of cells was increased significantly. The protein expression of E-cadherin was decreased significantly, while the protein expression level of the N-cadherin was increased significantly. The protein and mRNA expressions of MMP2, MMP9, snal1, and snal2 were significantly higher. The expression level of Smad1 was not significantly changed, while the phosphorylation of Smad1 was significantly increased. In the BMP4-siRNA group, the migrating number cells was significantly decreased. The protein expression of E-cadherin was increased significantly, while the expression of N-cadherin was significantly decreased. The protein and mRNA expressions of MMP2, MMP9, snal1, and snal2 were significantly lower than that of the control group. The expressions of Smad1 and phosphorylation of Smad1 were not significantly changed.

CONCLUSIONS

BMP4 enhances cell migration and promotes cell EMT through Smad1 signaling pathway. Abnormal BMP4 mediates migration and EMT through other relevant signaling pathways resulting in NSCL/P. The study provides new insight into the mechanisms of NSCL/P associated with BMP4.n.

Identification of an ALK-2 inhibitor as an agonist for intercellular exchange and tumor delivery of nanomaterial

Inefficient extravasation and penetration in solid tissues hinder the clinical outcome of nanoparticles (NPs). Recent studies have shown that the extravasation and penetration of NPs in solid tumor was mostly achieved via an active transcellular route. For this transport process, numerous efforts have been devoted to elucidate the endocytosis and subcellular trafficking of NPs. However, how they exit from one cell and re-enter into neighboring ones (termed intercellular exchange) remains poorly understood. We previously developed cellular assays that exclusively quantify the intercellular exchange of NPs in vitro. Our study showed that a significant portion of NPs are transferred inside extracellular vesicles (EVs). Pharmacological inhibition of EV biogenesis significantly reduced the tumor accumulation and vascular penetration of both inorganic and organic NPs in vivo. Intrigued by this result, we performed here a manual chemical screen with our assay, which identified that LDN-214117 (an inhibitor for activin receptor-like kinase-2, ALK-2) is an agonist of NP intercellular exchange. We further showed that LDN-214117 regulates the intercellular exchange by increasing the EV biogenesis. Mechanistic investigation showed that LDN-214117 functions via BMP (bone morphogenetic protein)-MAPK (mitogen-activated protein kinase) signaling pathway to increase EV biogenesis. We further demonstrated that LDN-214117 treatment in vivo enhanced the tumor accumulation and vascular penetration of a variety of NPs in multiple tumor models, which improves their antitumor efficacy. Overall, we showcase here the identification of a novel chemical compound with our intercellular exchange assays to modulate EV biogenesis and EV-mediated transport, thus boosting up the delivery and therapeutic efficacy of nanomaterial.

The Role of Bone Morphogenetic Protein 4 in Lung Diseases

Bone morphogenetic protein 4 (BMP4) is a multifunctional secretory protein that belongs to the transforming growth factor β superfamily. BMPs transduce their signaling to the cytoplasm by binding to membrane receptors of the serine/threonine kinase family, including BMP type I and type II receptors. BMP4 participates in various biological processes, such as embryonic development, epithelial-mesenchymal transition, and maintenance of tissue homeostasis. The interaction between BMP4 and the corresponding endogenous antagonists plays a key role in the precise regulation of BMP4 signaling. In this paper, we review the pathogenesis of BMP4-related lung diseases and the foundation on which BMP4 endogenous antagonists have been developed as potential targets.

Bone Morphogenetic Protein Signaling in Cancer; Some Topics in the Recent 10 Years

Bone morphogenetic proteins (BMPs), members of the transforming growth factor-β (TGF-β) family, are multifunctional cytokines. BMPs have a broad range of functions, and abnormalities in BMP signaling pathways are involved in cancer progression. BMPs activate the proliferation of certain cancer cells. Malignant phenotypes of cancer cells, such as increased motility, invasiveness, and stemness, are enhanced by BMPs. Simultaneously, BMPs act on various cellular components and regulate angiogenesis in the tumor microenvironment. Thus, BMPs function as pro-tumorigenic factors in various types of cancer. However, similar to TGF-β, which shows both positive and negative effects on tumorigenesis, BMPs also act as tumor suppressors in other types of cancers. In this article, we review important findings published in the recent decade and summarize the pro-oncogenic functions of BMPs and their underlying mechanisms. The current status of BMP-targeted therapies for cancers is also discussed.

Shear Stress Alterations Activate BMP4/pSMAD5 Signaling and Induce Endothelial Mesenchymal Transition in Varicose Veins

Chronic venous diseases, including varicose veins, are characterized by hemodynamic disturbances due to valve defects, venous insufficiency, and orthostatism. Veins are physiologically low shear stress systems, and how altered hemodynamics drives focal endothelial dysfunction and causes venous remodeling is unknown. Here we demonstrate the occurrence of endothelial to mesenchymal transition (EndMT) in human varicose veins. Moreover, the BMP4-pSMAD5 pathway was robustly upregulated in varicose veins. In vitro flow-based assays using human vein, endothelial cells cultured in microfluidic chambers show that even minimal disturbances in shear stress as may occur in early stages of venous insufficiency induce BMP4-pSMAD5-based phenotype switching. Furthermore, low shear stress at uniform laminar pattern does not induce EndMT in venous endothelial cells. Targeting the BMP4-pSMAD5 pathway with small molecule inhibitor LDN193189 reduced SNAI1/2 expression in venous endothelial cells exposed to disturbed flow. TGFβ inhibitor SB505124 was less efficient in inhibiting EndMT in venous endothelial cells exposed to disturbed flow. We conclude that disturbed shear stress, even in the absence of any oscillatory flow, induces EndMT in varicose veins via activation of BMP4/pSMAD5-SNAI1/2 signaling. The present findings serve as a rationale for the possible use of small molecular mechanotherapeutics in the management of varicose veins.

DDX39 Overexpression Predicts a Poor Prognosis and Promotes Aggressiveness of Melanoma by Cooperating With SNAIL

This study aimed to investigate the prognostic value and molecular mechanism of DDX39 and its effector SNAIL in melanoma. First, overexpression of DDX39 in melanoma, which was identified by database analysis, was further validated in patient tissues. Cell growth, cell cycle, cell migration, and cell invasion assays were then performed to evaluate the effects of downregulated DDX39 on the melanoma cell proliferation and aggressiveness. The same approaches were also used to reveal the cooperation of the transcription factor SNAIL with DDX39 to promote the aggressiveness of melanoma cells. We found that the expression of DDX39 was significantly upregulated in melanoma tissue compared to pigmented nevus tissue, and it was positively correlated with the clinical stage defined by the American Joint Committee on Cancer (AJCC) and the prognosis. Downregulation of DDX39 in melanoma cells was found to significantly inhibit cell proliferation, increase G2/M cell cycle arrest, enhance caspase-mediated cell apoptosis, and suppress cell invasion and migration. In addition, we demonstrated that the overexpression of SNAIL could restore the cell growth and aggressiveness impaired by DDX39 RNA interference. Immunohistochemical staining also showed a positive correlation between DDX39 overexpression and SNAIL overexpression in melanoma tissues, suggesting that SNAIL is one of the effectors activated by DDX39. In summary, the overexpression of DDX39 and SNAIL was positively related to the poor prognosis of melanoma patients and the increased aggressiveness of melanoma cells. Our study provides valuable evidence regarding the prognostic value of DDX39 and SNAIL as well as their potential as novel therapeutic targets for treating melanoma patients.