RNAi-mediated A disintegrin and metalloproteinase 9 gene silencing inhibits the tumor growth of non-small lung cancer in vitro and in vivo

Structure, regulatory factors and cancer-related physiological effects of ADAM9

The ADAMs family belongs to the transmembrane protein superfamily of zinc-dependent metalloproteases, which consists of multiple domains. These domains have independent but complementary functions that enable them to participate in multiple biological processes. Among them, ADAM9 can not only participate in the degradation of extracellular matrix as a metalloprotease, but also mediate tumor cell adhesion through its deintegrin domain, which is closely related to tumor invasion and metastasis. It is widely expressed in a variety of tumor cells and can affect the proliferation, invasion and metastasis of related cancer cells. We provide our views on current progress, its increasing importance as a strategic treatment goal, and our vision for the future of ADAM9.

Silencing ICAM-1 reduces the adhesion of vascular endothelial cells in mice with immunologic contact urticaria

OBJECTIVE

Immunologic contact urticaria (ICU) is an immediate response of wheal caused by various contactants in vulnerable individuals, with undefined pathogenesis.

METHODS

In the present study, we aim to explore the effects of intercellular cell adhesion molecule-1 (ICAM-1) gene silencing by RNA inference (RNAi) on vascular endothelial cells (VECs) adhesion molecule expression and cell-cell adhesion in ICU mice. Sixty BALB/c mice were selected, among which 48 mice were used for establishment of ICU models. VECs from normal and ICU mice were grouped into different groups. Expressions of ICAM-1, eosinophilic cationic protein (ECP), total immunologlobulin E (tIgE), L-selectin (CD62L), integrin, alpha L (CD11a) in tissues and cells were evaluate by RT-qPCR and western blotting. Cell proliferation was evaluated by MTT assay and EdU staining and cell adhesive function by cell-cell adhesion assay.

RESULTS

Compared with normal mice, ICU mice had increased expressions of ICAM-1, ECP, tIgE, CD62L, and CD11a.ICAM-1 gene silencing decreased expressions of ECP, tIgE, CD62L, and CD11a, enhanced cell proliferation, and more activity in cell adhesion.

CONCLUSION

These findings indicate that RNAi-mediated gene silencing of ICAM-1 may decrease VECs adhesion expression and reduce cell-cell adhesion in mice with ICU.

Effects of RNA interference-mediated E-selectin gene silencing on cell adhesion molecule expression and cell-cell adhesion in vascular endothelial cells in mice with immunologic contact urticaria

Contact urticaria is recognized as the wheal and flare reaction at a site from direct contact with a chemical or protein agent. Ongoing studies have proposed that gene silencing may have a promising future in finding optimal treatment of a variety of disease; hence, the aim of the study was to investigate the effect of RNA interference-mediated E-selectin ( SELE) gene silencing on cell adhesion molecule expression and on cell-cell adhesion in vascular endothelial cells (VECs) in a mouse model of immunologic contact urticaria (ICU). Following the successful establishment of mouse models of ICU induced by antidinitrophenol immunoglobulin E (IgE) combining 2,4-dinitrofluorobenzene challenge, enzyme-linked immunosorbent assay and immunohistochemistry were used to measure the levels of IgE, interleukin 4 (IL-4), interferon-γ (IFN-γ), and histamine as well as the positive expression rate of SELE, respectively. The siRNA- SELE vector was constructed and transfection efficiency was estimated prior to performing quantitative reverse-transcription polymerase chain reaction and Western blot assay to determine the relative expression of SELE, eosinophil cationic protein (ECP), intercellular adhesion molecule 1 (ICAM-1), L-selectin (CD62L), and the alpha chain of leukocyte function-associated antigen-1 (CD11a). Adhesion assay was then performed to assess the cell adhesion ability in VECs. Elevated levels of IgE, IL-4, IFN-γ, and histamine and increased positive expression rate of SELE were indicative of successful establishment of mouse models of ICU. Furthermore, the relative expression levels of SELE, ECP, ICAM-1, CD62L, and CD11a were highest in the OE- SELE group. Besides, cell adhesion ability of VECs was notably promoted. Collectively, the current study define the potential role of SELE silencing as an inhibitor to ICU development by inhibiting cell adhesion ability of VECs.

The pleiotropic roles of ADAM9 in the biology of solid tumors

A disintegrin and a metalloprotease (ADAM) 9 is a metzincin cell-surface protease involved in several biological processes such as myogenesis, fertilization, cell migration, inflammatory response, proliferation, and cell-cell interactions. ADAM9 has been found over-expressed in several solid tumors entities such as glioma, melanoma, prostate cancer, pancreatic ductal adenocarcinoma, gastric, breast, lung, and liver cancers. Immunohistochemical analyses highlight ADAM9 expression by actual cancer cells and associate its abundant presence with clinicopathological features such as shortened overall survival, poor tumor grade, de-differentiation, therapy resistance, and metastasis formation. In each of these tumors, ADAM9 may contribute to tumor biology via proteolytic or non-proteolytic mechanisms. For example, in liver cancer, ADAM9 has been found to shed MHC class I polypeptide-related sequence A, contributing towards the evasion of tumor immunity. ADAM9 may also contribute to tumor biology in non-proteolytic ways probably through interaction with different integrins. For example, in melanoma, the interaction between ADAM9 and β1 integrins facilitates tumor stroma cross talks, which then promotes invasion and metastasis via the activation of MMP1 and MMP2. In breast cancer, the interaction between β1 integrins on endothelial cells and ADAM9 on tumor cells facilitate tumor cell extravasation and invasion to distant sites. This review summarizes the present knowledge on ADAM9 in solid cancers, and the different mechanisms which it employ to drive tumor progression.

MicroRNA‑302a suppresses cell proliferation, migration and invasion in osteosarcoma by targeting ADAM9

Osteosarcoma (OS) is the most frequent malignant primary bone tumor arising from primitive bone‑forming mesenchymal cells in children and adolescents. The dysregulation of microRNAs (miRNAs) has been reported in OS, and these aberrantly expressed miRNAs are involved in the initiation and progression of OS. The aim of the present study was to investigate the expression and functions of miRNA‑302a (miR‑302a) in OS and its underlying mechanism. It was found that the expression of miR‑302a was reduced in OS tissues and cell lines. The low expression of miR‑302a was significantly correlated with tumor‑node‑metastasis stage and metastasis. The ectopic overexpression of miR‑302a inhibited the proliferation, migration and invasion of OS cells. Bioinformatics analysis showed that a disintegrin and metalloproteinase 9 (ADAM9) was a potential target gene of miR‑302a. Subsequently, reverse transcription‑quantitative polymerase chain reaction and western blot analyses revealed that miR‑302a regulated the expression of ADAM9 at the post‑transcriptional level in OS cells. In addition, a luciferase reporter assay demonstrated that miR‑302a directly targeted the 3'untranslated region of ADAM9. In clinical OS tissues, the mRNA expression of ADAM9 was upregulated and inversely correlated with the expression of miR‑302a. In addition, the effects of ADAM9 knockdown on cell proliferation, migration and invasion were similar to those induced by the overexpression of miR‑302a in OS cells. These findings suggested that miR‑302a inhibited OS cell growth and metastasis by targeting ADAM9. miR‑302a may serve as a potential therapeutic target for patients with OS.

microRNA-590 suppresses the tumorigenesis and invasiveness of non-small cell lung cancer cells by targeting ADAM9

microRNAs (miRNAs), a family of small non-coding RNA molecules, are implicated in cancer growth and progression. In the present study, we examined the expression and biological roles of miR-590 in non-small cell lung cancer (NSCLC). Compared to normal lung tissues, miR-590 expression was downregulated in primary NSCLCs and, to a greater extent, in corresponding brain metastases. NSCLC cell lines with high metastatic potential had significantly (P < 0.05) lower levels of miR-590 than those with low metastatic potential. Re-expression of miR-590 suppressed NSCLC cell proliferation, colony formation, migration, and invasion in vitro and tumorigenesis in vivo. In contrast, inhibition of miR-590 enhanced the migration and invasion of NSCLC cells. Mechanistic studies revealed that a disintegrin and metalloproteinase 9 (ADAM9) was a direct target of miR-590. Delivery of miR-590 mimic was found to decrease endogenous ADAM9 expression in NSCLC cells. Enforced expression of a miRNA-resistant form of ADAM9 significantly restored the aggressive behaviors in miR-590-overexpressing NSCLC cells. Taken together, our data reveal miR-590 as a tumor suppressor in NSCLC, which is at least partially mediated through targeting of ADAM9. Restoration of miR-590 may provide a promising therapeutic strategy for NSCLC.

The Angiogenic Effect of microRNA-21 Targeting TIMP3 through the Regulation of MMP2 and MMP9

microRNAs are a novel set of small, non-protein-coding nucleotide RNAs that negatively regulate the expression of target mRNAs. miRNA-21 is a microRNA that is highly enriched in endothelial cells. miRNA-21 has been shown to be a potential pro-angiogenic factor in some biological systems. Our previous study showed that the expression of miRNA-21 was up-regulated after spinal cord injury. However, the effect of miRNA-21 on angiogenesis in the spinal cord was unclear. In this study, to understand the role of miRNA-21 on injured endothelial cells exclusively, an oxygen and glucose deprivation model of endothelial cells was constructed, and the up-regulation of miRNA-21 was discovered in this model. An increased level of miRNA-21 by mimics promoted the survival, migration and tube formation of endothelial cells, which simultaneously inhibited tissue inhibitor of metalloproteinase-3 (TIMP3) expression and promoted matrix metalloproteinase-2 (MMP2) and matrix metalloproteinase-9 (MMP9) expression and secretion. A decreased level of miRNA-21 by antagomir exerted an opposite effect. As is well known, survival, migration and tube formation of endothelial cells are necessary prerequisites for angiogenesis after injury. TIMP3 was validated as a direct target of miRNA-21 by dual-luciferase reporter assay. Silencing with small interfering RNA against TIMP3 promoted tube formation and increased MMP2 and MMP9 expression at the protein level. In vivo, we found that decreased levels of miRNA-21 inhibited angiogenesis after spinal cord injury in rats using synchrotron radiation micro-computed tomography. In summary, these findings suggest that miRNA-21 has a protective effect on angiogenesis by reducing cell death and promoting cell survival, migration and tube formation via partially targeting the TIMP3 by potentially regulating MMP2 and MMP9. TIMP3 is a functional target gene. Identifying the role of miRNA-21 in the protection of angiogenesis might offer a novel therapeutic target for secondary spinal cord injury, in which angiogenesis is indispensable.

Combined RNAi targeting human Stat3 and ADAM9 as gene therapy for non-small cell lung cancer

Previous studies have demonstrated that human signal transducer and activator of transcription 3 (Stat3) and disintegrin and metalloproteinase 9 (ADAM9) are promising targets for RNA interference (RNAi)-based gene therapy for human non-small cell lung cancer (NSCLC). Thus, in the present study, the recombinant lentiviral (Lv) small hairpin (sh)RNA expression plasmids Lv/sh-Stat3 and Lv/sh-ADAM9, which targeted Stat3 and ADAM9, respectively, were constructed and subsequently infected into the A549 human NSCLC cell line. Cell proliferation, migration, invasion and apoptosis were determined in vitro in A549 cells following treatment with Lv/sh-Stat3 or Lv/sh-ADAM9 alone or in combination. In addition, the combined effect of Lv/sh-Stat3 and Lv/sh-ADAM9 gene therapy was evaluated in vivo using A549 xenograft models in nude mice. The in vitro experiments demonstrated that A549 cells treated with a combination of Lv/sh-Stat3 and Lv/sh-ADAM9 exhibited a significant additive effect in their cell proliferation, migration, invasion and apoptosis abilities, compared with A549 cells treated with Lv/sh-Stat3 or Lv/sh-ADAM9 alone. The in vivo experiments conducted in A549 xenograft tumor mouse models revealed that the combined treatment with Lv/sh-Stat3 and Lv/sh-ADAM9 exerted an additive effect on tumor growth inhibition, compared with the treatment with Lv/sh-Stat3 or Lv/sh-ADAM9 alone. These results suggested that combined RNAi gene therapy targeting human Stat3 and ADAM9 may be a novel and promising strategy for the treatment of NSCLC.