Circular RNA Circ_0122396 Regulates Human Lens Epithelial Cell Progression by Regulating miR-23a-3p and MMP16 in Age-Related Cataract.

BACKGROUND: CircRNA plays a regulatory role in multiple life processes. Circ_0122396 could participate in the regulation of age-related cataract (ARC) progression. However, the precise molecular mechanisms of circ_0122396 In ARC remain enigmatic. METHODS: Circ_0122396, microRNA (miR)-23a-3p, and matrix metalloprotease (MMP)-16 (MMP16) expression levels were detected via quantitative real-time polymerase chain reaction. Western blot was used to detect the levels of MMP16 and apoptosis-related proteins. Cell counting kit-8 analysis and 5-ethynyl-2'-deoxyuridine assay were used to assess human lens epithelial cells (HLECs) proliferation. Flow cytometry was performed to determine cell apoptosis. Levels of malondialdehyde (MDA) and glutathione peroxidase (GSH-PX) were measured using commercial kits. Luciferase reporter assay, RNA immunoprecipitation (RIP) assay, and RNA pull-down assay were used to examine the interaction among circ_0122396, miR-23a-3p, and MMP16. RESULTS: Circ_0122396 and MMP16 were down-regulated while miR-23a-3p was up-regulated in ARC. H2O2 constrained proliferation and GSH-PX level, promotes apoptosis and MDA level in HLECs, and overexpression of circ_0122396 attenuated these effects. miR-23a-3p was a direct target of circ_0122396, and MMP16 was a direct target of miR-23a-3p. The effect of circ_0122396 overexpression on H2O2-induced HLECs was reversed by miR-23a-3p, and MMP16 elevation overturned the impacts of miR-23a-3p in H2O2-induced HLECs. CONCLUSIONS: Circ_0122396 may regulate the progression of ARC via the miR-23a-3p/MMP16 pathway in H2O2-stimulated HLECs, which may serve as a potentially valuable biomarker and novel therapeutic target for ARC.

M1 macrophage-derived exosomes containing miR-150 inhibit glioma progression by targeting MMP16.

A large amount of clinical and experimental evidence indicates that M1 macrophages can inhibit tumor progression and expansion; however, the molecular mechanism by which macrophage-derived exosomes inhibit the proliferation of glioblastoma cells has not yet been elucidated. Here, we used M1 macrophage exosomes encapsulating microRNAs to inhibit the proliferation of glioma cells. Exosomes derived from M1 macrophages exhibited high expression levels of miR-150, and the inhibition of glioma cell proliferation mediated by exosomes derived from M1 macrophages was dependent on this microRNA. Mechanistically, miR-150 is transferred to glioblastoma cells through M1 macrophages and binds to MMP16, downregulating its expression and inhibiting glioma progression. Overall, these findings indicate that M1 macrophage-derived exosomes carrying miR-150 inhibit the proliferation of glioblastoma cells through targeted binding to MMP16. This dynamic mutual influence between glioblastoma cells and M1 macrophages provides new opportunities for the treatment of glioma.

MMP-16 as a New Biomarker for Predicting Prognosis and Chemosensitivity of Serous Ovarian Cancer: A Study Based on Bioinformatics Analysis.

OBJECTIVE: To explore the prognostic value of MMP-16 expression in patients with serous ovarian cancer and the usefulness of MMP-16 expression to predict sensitivity to chemoradiotherapy. METHODS: The relationship between MMP-16 expression and clinicopathological parameters of serous ovarian cancer was evaluated in The Cancer Genome Atlas (TCGA) database. Cox proportional hazard regression analysis was performed to measure the prognostic significance of MMP-16 in serous ovarian cancer. Dataset GSE51373 was applied to estimate the difference of MMP-16 expression between chemotherapy-sensitive group and resistant group of serous ovarian cancer. Receiver operating characteristic (ROC) curve was also drawn. In addition, the online tool Kaplan-Meier Plotter was used to assess the prognostic value of MMP-16 in patients with serous ovarian cancer. RESULTS: A total of 235 patients with serous ovarian cancer were included in the TCGA database. Cox regression univariate analysis showed that high expression of MMP-16 was not conducive to the overall survival of patients with serous ovarian cancer (hazard ratio [HR] = 1.47, 95% CI: 1.03~2.08; P < 0.05). The results of Cox regression multivariate analysis also demonstrated that there was a statistically significant difference. The results of the online database Kaplan-Meier Plotter analysis showed that the high expression of MMP-16 was not conducive to the progression-free survival (PFS) of patients with serous ovarian cancer (HR = 1.26, 95% CI: 1.06~1.29; P < 0.05). The expression of MMP-16 in the chemotherapy-sensitive group was notably lower than that in the chemotherapy-resistant group, which had a moderate predictive value in predicting the chemosensitivity of serous ovarian cancer (AUC = 0.7187). CONCLUSION: High expression of MMP-16 is not conducive to chemotherapy sensitivity and survival of patients with serous ovarian cancer, and has predictive value for chemotherapy resistance and prognosis.

microRNA-4429-5p suppresses the malignant development of colon cancer by targeting matrix metalloproteinase 16.

Colon cancer has been recognized as the major reason for global cancer-associated mortality. microRNA (miRNA, miR)-4429-5p has been documented to act as a tumor-suppressive miRNA in some cancers, but its effect on colon cancer remains elusive. In this study, the biological effects of miR-4429-5p were investigated both in vitro by MTT, 5-ethynyl-2'-deoxyuridine (EdU), wound healing, and transwell assays and in vivo by a xenograft mice model. Western blot, quantitative reverse transcription-polymerase chain reaction (qRT-PCR), and dual-luciferase assay were used to identify the binding of miR-4429-5p on matrix metalloproteinase 16 (MMP16) 3'-UTR. Our results suggested that overexpression of miR-4429-5p hindered colon cancer cell proliferation, migration, and invasion, whereas knockdown of miR-4429-5p exhibited the opposite effect in colon cancer cells. Mechanistically, miR-4429-5p directly bound to the 3'-UTR of MMP16 and led to inhibition of MMP16 protein. Overexpression of miR-4429-5p inhibited colon tumor growth by targeting MMP16. Taken together, our study revealed that miR-4429-5p prevented colon cancer progression through targeting MMP16, indicating miR-4429-5p as a promising target for treatment improvement for colon cancer.

LncRNA NEAT1 regulates MMP-16 by targeting miR-200a/b to aggravate inflammation in asthma.

Asthma is a common respiratory disease which is characterized by persistent airway inflammation. Abnormal expression of long non-coding RNAs (lncRNAs) is observed in asthma. However, whether lncRNA nuclear-enriched abundant transcript 1 (NEAT1) regulates asthmatic inflammation and its mechanism still needs to be further investigated. The expression levels of inflammatory factors (tumour necrosis factor (TNF)-α, interleukin (IL)-4, IL-13, and IL-10) were detected using reverse transcription quantitative real-time PCR (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA). MTT and flow cytometry assays were employed to determine cell proliferation and apoptosis, respectively. Dual luciferase reporter assay was performed to verify the relationship between miR-200a/b and MMP-16 or NEAT1. NEAT1 silencing markedly reduced TNF-α, IL-4, and IL-13 levels, while elevated IL-10 expression, suppressed cell proliferation, and promoted cell apoptosis. However, NEAT1 overexpression elicited the opposite effects on cell proliferation and inflammation cytokines secretion. What is more, NEAT1 negatively regulated miR-200a/b expression, and MMP16 was a target gene of miR-200a/b. miR-200a/b overexpression suppressed inflammation, cell proliferation, and enhanced cell apoptosis through regulation of MMP16. Moreover, MMP-16 overexpression or miR-200a/b inhibition abolished the regulatory effect of sh-NEAT1 on cell inflammation and apoptosis in BEAS-2B cells. NEAT1 acted as the role of sponge for miR-200a/b to regulate MMP-16 expression, thereby promoting asthma progression, suggesting that NEAT1 might have great potential as therapeutic target for asthma.

miRNA 146b-5p protects against atherosclerosis by inhibiting vascular smooth muscle cell proliferation and migration.

Aim: To explore the potentially important role of miRNA 146b-5p (miR-146b) during the development of atherosclerosis. Materials & methods: Proliferation, migration and luciferase assays and mouse models were used to determine the functions of miR-146b. Results: miR-146b was identified as substantially upregulated in the aortic plaques of ApoE-/- mice as well as in response to inflammatory cytokines. Overexpression of miR-146b repressed proliferation and migration of vascular smooth muscle cells by downregulating Bag1 and Mmp16, respectively. Adeno-associated virus-mediated miR-146b overexpression inhibited neointima formation after carotid injury and suppressed atherosclerotic plaque formation in Western diet-induced ApoE-/- mice. Conclusion: miR-146b is a novel regulator of vascular smooth muscle cell function induced by inflammatory response, specifically in neointima formation, and offers a novel therapeutic strategy for treating atherosclerosis.

Role of lncRNA NEAT1 mediated by YY1 in the development of diabetic cataract via targeting the microRNA-205-3p/MMP16 axis.

OBJECTIVE: We aimed at investigating the possible role and mechanism of NEAT1 in the pathogenesis of diabetic cataract. PATIENTS AND METHODS: YY1 and NEAT1 expressions in anterior lens capsule collected from diabetic cataract (DC) patients and normal controls were examined by quantitative real-time polymerase chain reaction (qRT-PCR) analysis, and their correlation was analyzed. The binding site between YY1 and NEAT1 sequences was predicted by JASPAR and detected by Dual-Luciferase reporter assay and chromatin immunoprecipitation (ChIP) assay. The proliferation and apoptosis of high-glucose-induced cells with NEAT1 knockdown were detected. Potential downstream targets of NEAT1 were predicted by bioinformatics and detected by Dual-Luciferase reporter assay. RESULTS: YY1 and NEAT1 expressions in the anterior capsule tissue of DC lens were remarkably reduced and positively correlated. Dual-Luciferase reporter assay and ChIP confirmed that YY1 could bind to locus 2 of NEAT1. Knockdown of NEAT1 inhibited proliferation while promoted apoptosis under high glucose conditions. Further mechanism studies revealed that knockdown of NEAT1 could upregulate microRNA-205-3p, and MMP16 was a potential target of miR-205. CONCLUSIONS: The low expression of YY1 induces NEAT1 downregulation, which regulates microRNA-205-3p/MMP16 axis and thus participates in the development of DC.

miR-325-3p Overexpression Inhibits Proliferation and Metastasis of Bladder Cancer Cells by Regulating MT3.

BACKGROUND miRNAs have been widely used in cancer treatment. Our study was designed to explore the effects of miR-325-3p in bladder cancer cells. MATERIAL AND METHODS Levels ofd miR-325-3p and MT3 in bladder cancer tissues and cells were assessed by quantitative real-time polymerase chain reaction (qRT-PCR). miR-325-3p mimics were transfected into bladder cancer T24 cells, and cell migration and invasion rates and cell proliferation were assessed by transwell assay and Cell Counting Kit-8 (CCK-8). The target mRNA for miR-325-3p was predicted by Targetscan7.2 and confirmed by dual-luciferase reporter assay. More experiments were performed to confirm the effects of miR-325-3p and MT3 in T24 cells. Additionally, the levels of TIMP-2, MMP9, and E-cadherin were assessed by Western blotting to identify the effects of miR-325-3p and MT3 on epithelial-mesenchymal transition (EMT). RESULTS miR-325-3p expression was reduced and MT3 was increased in bladder cancer tissues and bladder cancer cells. miR-325-3p mimics suppressed cell proliferation ability and invasion and migration rates of T24 cells. Moreover, miR-325-3p was confirmed to target MT3. Further experiments showed that the effects of increased cell proliferation, invasion, migration, and EMT promoted by MT3 overexpression were abolished by miR-325-3p mimics, proving that miR-325-3p is a tumor suppressor through targeting MT3 in bladder cancer cells. CONCLUSIONS Downregulation of miR-325-3p in bladder cancer regulates cell proliferation, migration, invasion, and EMT by targeting MT3. Furthermore, miR-325-3p is a potential therapeutic target in treating bladder cancer.

Sevoflurane suppresses migration and invasion of glioma cells by regulating miR-146b-5p and MMP16.

Background: Glioma is the most common brain tumor with poor prognosis all over the world. Anesthetics have been demonstrated to have important impacts on cell migration and invasion in different cancers. However, the underlying mechanism that allows anesthetics-mediated progression of glioma cells remains elusive. Methods: Sevoflurane (Sev), a class of common anesthetics, was used to expose to U87-MG and U251 cells. The expressions of microRNA-146b-5p (miR-146b-5p) and matrix metallopeptidase 16 (MMP16)were measured by quantitative real-time polymerase chain reaction or western blot. Transfection was performed in glioma cells with miR-146b-5p inhibitor, inhibitor negative control, MMP16 overexpression vector, empty vector, small interfering RNA against MMP16 or scramble. Cell migration and invasion were analyzed by the trans-well assay. The interaction between miR-146b-5p and MMP16 was explored by luciferase activity and RNA immunoprecipitation assays. Results: Sev treatment inhibited migration and invasion of glioma cells. The expression of miR-146b-5p was enhanced and MMP16 protein was decreased in glioma cells after exposure of Sev. Knockdown of miR-146b-5p or overexpression of MMP16 reversed Sev-induced inhibition of migration and invasion of glioma cells. Moreover, MMP16 was indicated as a target of miR-146b-5p and its silencing attenuated the regulatory role of miR-146b-5p abrogationin Sev-treated glioma cells. Conclusion: Sev impeded cell migration and invasion through regulating miR-146b-5p and MMP16 in glioma, indicating a novel theories foundation for the application of anesthetics like Sev in glioma.

Rosmarinic inhibits cell proliferation, invasion and migration via up-regulating miR-506 and suppressing MMP2/16 expression in pancreatic cancer.

Pancreatic cancer is the fourth leading cause of cancer-related deaths worldwide. However, therapeutic strategies for the treatment of pancreatic cancer are still limited. Therefore, it is urgent for us to develop novel effective therapies for pancreatic cancer. In this study, we explored the effects of rosmarinic acid on pancreatic progression and explored the underlying molecular mechanisms. Rosmarinic acid significantly suppressed cell viability, cell growth, cell invasion and migration as well as epithelial mesenchymal transition (EMT) of pancreatic cancer cells, and induced cell apoptosis in pancreatic cells. In addition, rosmarinic acid significantly up-regulated the expression of miR-506 in pancreatic cancer cells, and knockdown of miR-506 attenuated the suppressive effects of rosmarinic acid on cell growth, cell invasion and migration and EMT, and prevented the enhanced effects of rosmarinic acid on cell apoptosis in pancreatic cancer cells. Mechanistically, the luciferase reporter assay showed that miR-506 targeted the 3' untranslated region of matrix metalloproteinase (MMP)-2/16, and miR-506 overexpression and rosmarinic acid treatment suppressed the expression of MMP2/16 in pancreatic cancer cells. Overexpression of MMP2/16 attenuated the inhibitory effects of rosmarinic acid on pancreatic cell invasion and migration. In vivo studies showed that rosmarinic acid dose-dependently suppressed tumor growth of pancreatic cancer cells, and increased the expression of miR-506, while suppressed the expression of MMP2/16 and Ki-67 in dissected tumor tissues from xenograft nude mice. Collectively, our results for the first time revealed the anti-tumor effects of rosmarinic acid in pancreatic cancer, and the anti-tumor effects of rosmarinic acid were via regulating the miR-506/MMP2/16 axis in pancreatic cancer.

Overexpression of Aiolos promotes epithelial-mesenchymal transition and cancer stem cell-like properties in lung cancer cells.

Aiolos/Ikaros family zinc finger 3 (IKZF3), a member of the Ikaros family of lymphocyte maturation-driving transcription factors, is highly expressed in hematopoietic malignancies. However, its role in epithelial-mesenchymal transition (EMT) and cancer stem cell (CSC)-like properties in lung cancer remains unknown. Human lung cancer cell lines H1299 with overexpressing Aiolos (H1299-Aiolos) and A549 with overexpressing Aiolos (A549-Aiolos) were generated by stable transfection. Cell migration and invasion assays were done to demonstrate their invasion and migration ability. Sphere formation assay was used to determine their tumor-initiating capability. Aiolos overexpression induced EMT and increased migration/invasiveness in H1299 and A549 cells. Aiolos overexpression also increased metastatic ability in vivo. Aiolos overexpression upregulated the expression of Twist and matrix metalloproteinase 16 (MMP16). By using knockdown of Twist or an inhibitor of phosphatidylinositol (PI) 3-kinase, EMT, migration/invasiveness ability, and MMP16 expression were reversed in H1299-Aiolos and A549-Aiolos cells. Overexpression of Aiolos upregulated the CSC-like properties in lung cancer cells, and were also reversed by an inhibitor of PI 3-kinase. For lung cancer cells, Aiolos overexpression promotes EMT and CSC-like properties through upregulating the PI 3-kinase/Akt pathway. The information is helpful for developing therapeutic strategies targeting Aiolos expression for lung cancer treatment.

MiR-155 promotes the proliferation and migration of breast cancer cells via targeting SOCS1 and MMP16.

OBJECTIVE: The aim of this study was to investigate the effect of miR-155 on the proliferation and migration of breast cancer cells, and to explore the underlying mechanism. MATERIALS AND METHODS: The breast cancer cell line MDA-MB-231 was transfected with miR-155 mimics, inhibitor or negative control, respectively. The expression level of miR-155 was detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Subsequently, the proliferation of MDA-MB-231 cells was detected by multi-cellular tumor spheroid (MTS) and colony formation assay. Cell migration was examined by transwell assay and scratch test. In addition, qRT-PCR was performed to analyze the expression of matrix metallopeptidase 16 (MMP16) after miR-155 mimics or inhibitor transfection in MDA-MB-231 cells. Meanwhile, Western blot was used to evaluate the protein expression levels of suppressor of cytokine signaling 1 (SOCS1) and MMP16 after miR-155 mimics or inhibitor transfection. RESULTS: QRT-PCR results showed that miR-155 mimics significantly increased the expression of miR-155 in MDA-MB-231 cells, whereas miR-155 inhibitor markedly decreased miR-155 expression (p < 0.05). Meanwhile, MTS and colony formation assay indicated that the proliferation of MDA-MB-231 cells was remarkably increased after miR-155 mimics transfection. However, miR-155 inhibitor transfection exhibited the opposite result in cell proliferation (p < 0.05). Moreover, miR-155 overexpression significantly increased the migration of MDA-MB-231 cells (p < 0.05). Western blot further confirmed that miR-155 overexpression down-regulated the expression level of target protein SOCS1 and upregulated the expression level of MMP16. CONCLUSIONS: We found that miR-155 significantly enhanced the proliferation and migration of MDA-MB-231 cells, which might serve as an oncogene in breast cancer. Therefore, it is preliminarily believed that miR-155 plays an important role in the proliferation and migration of breast cancer cells via down-regulating the expression of SOCS1 and up-regulating the expression of MMP16.

HOXA11-AS promotes the growth and invasion of renal cancer by sponging miR-146b-5p to upregulate MMP16 expression.

Recently, increasing studies showed that long noncoding RNAs (lncRNAs) play critical roles in tumor progression. However, the function and underlying mechanism of HOMEOBOX A11 antisense RNA (HOXA11-AS) on renal cancer remain unclear. In the current study, our data showed that the expression of HOXA11-AS was significantly upregulated in clear cell renal cell carcinoma (ccRCC) tissues and cell lines. High HOXA11-AS expression was associated with the advanced clinical stage, tumor stage, and lymph node metastasis. Function assays showed that HOXA11-AS inhibition significantly suppressed renal cancer cells growth, invasion, and ETM phenotype. In addition, underlying mechanism revealed that HOXA11-AS could act as a competing endogenous RNA (ceRNA) that repressed miR-146b-5p expression, which regulated its downstream target MMP16 in renal cancer. Taken together, our findings suggested that HOXA11-AS could promote renal cancer cells growth and invasion by modulating miR-146b-5p-MMP16 axis. Thus, our findings suggested that HOXA11-AS could serve as potential therapeutic target for the treatment of renal cancer.

[Expression of miR-146b in peripheral blood serum and aortic tissues in patients with acute type Stanford A aortic dissection and its clinical significance].

OBJECTIVE: To explore expression of miR-146b in peripheral blood serum and aortic wall tissues in patients with acute Stanford type A aortic dissection (TAAD), and to discuss the significance and underlying mechanisms.
 Methods: The subjects were divided into a control group (excluded relative aortic diseases) (n=23) and a TAAD group (n=27). The miR-146b levels of serum and aortic wall tissues were detected by quantitative real-time PCR (qRT-PCR). Serum miR-146b and aortic wall tissues miR-146b were compared among different risk TAAD groups. The correlations between miR-146b and severity of aortic dissection were analyzed. MiR-146b related target genes were predicted by the DIANA LAB-TarBase 6.0 and TargetScan.
 Results: The expression levels of miR-146b in the serum and aortic wall tissues in the TAAD group were significantly elevated compared with those in the control group (P<0.001). Compared with the mild risk group, the miR-146b levels of serum and aortic wall tissues were significantly higher in the moderate risk and severe risk groups (P<0.05). The expression of miR-146b was positively correlated with the risk severity of TAAD patients (r=0.862, 0.872; P<0.05). Nuclear factor kappa B1 (NF-κB1), tumor necrosis factor receptor-associated factor 6 (TRAF6), matrix metalloproteinase 16 (MMP16) and actin alpha 2 (ACTA2) were miR-146b related target genes.
 Conclusion: The upregulation of miR-146b in peripheral blood serum and aortic wall tissues may contribute to the pathogenesis of TAAD and the severity of this disease.

Post-transcriptional Regulation of MMP16 and TIMP2 Expression via miR-382, miR-410 and miR-200b in Endometrial Cancer.

BACKGROUND/AIM: The post-transcriptional regulation of matrix metalloproteinases (MMPs) via microRNAs (miRNAs) has been recently described in numerous human malignancies. However, the exact mechanisms of miRNA-mediated MMPs deregulation in endometrial cancer (EC) remain unclear. Herein, we aimed to analyze the expression of MMP2, MMP16 and TIMP2 and identify miRNAs that modulate their expression. MATERIALS AND METHODS: Protein expression was assessed by immunohistochemistry in formalin-fixed paraffin-embedded EC samples. Target prediction algorithms were applied to select miRNAs binding the 3'UTRs of MMP16 (miR-377, miR-382, miR-410, miR-200b) or TIMP2 (miR-200b), and their levels were measured by qPCR in laser capture-microdissected tissue fragments. Luciferase assays and western blotting were used to indicate individual miRNA- mRNA interactions. RESULTS: Overexpression of MMP2 and MMP16 in cancerous tissues corresponded to down-regulation of miR-377, miR-382 and miR-410, while decreased expression of TIMP2 was associated with miR-200b up-regulation. In vitro experiments confirmed direct regulation of MMP16 by miR-382 and miR-410, and TIMP2 by miR-200b in EC Ishikawa cells. CONCLUSION: We demonstrated novel mechanisms of miRNA-mediated regulation of MMPs activity in EC.

A new role of the membrane-type matrix metalloproteinase 16 (MMP16/MT3-MMP) in neural crest cell migration.

Neural crest cells (NCCs) are a transient population of neuroectodermal-originated cells that populate the dorsal neural tube (dNT), before migrating and giving rise to multiple cell lineages in the developing embryo. Prior to their migration, NCCs undergo epithelial-to-mesenchymal-transition (EMT) through which they lose cell contacts and detach from the dNT to invade their surrounding environment. Multiple signals and transcription factors have been identified to regulate these events. Yet, less is known regarding effectors that act downstream to execute the actual NCC separation and migration. Matrix metalloproteinases (MMPs) are a family of proteases that degrade the extracellular matrix as well as other pericellular proteins during processes of tissue remodeling, angiogenesis and metastasis. Previously, we and others have demonstrated the role of the gelatinases MMP2 and MMP9 during the onset of NCC migration. Several evidences link the cleavage and activation of these secreted gelatinases to the activity of membrane-type MMPs (MT-MMP), such as MMP14 and MMP16, which are tethered to plasma membrane and affect various cellular behaviors. The aim of this study was to investigate whether MMP16 acts in NCCs. Here we demonstrate the expression of MMP16 mRNA and protein in cranial NCCs in avian embryos. Knockdown of MMP16 inhibited NCC migration. This inhibition was rescued by the addition of recombinant MMP16, which was also sufficient to increase proper NCC migration. Furthermore, excess MMP16 caused enhanced NCC EMT, concomitant with degradation of dNT-related proteins, laminin and N-cadherin. Altogether, these results uncover MMP16 as a new effector participating in EMT and in the migration of NCCs.

Engineered domain swapping indicates context dependent functional role of RNA G-quadruplexes.

RNA domain swapping typically demonstrates conservation of the native function of the domain in a non-native context. In contrast, we employed RNA engineering to demonstrate deviation of G-quadruplex (GQ) function that is contingent upon its context dependent location, which is opposite to their native functional role. Known translation repressing RNA GQs were engineered into human VEGF IRES A replacing the endogenous GQ domain essential for translation. Alternatively, the translation inhibitory GQ motif within the 5'-UTR of MT3-MMP mRNA was replaced with two known GQ motifs that are essential for translation. The results indicate that the engineered GQ domains can adopt GQ structures in a foreign environment with a functional role reversal to accommodate the need of the endogenous swapped motifs. The observations establish the functionality and context dependent modularity of RNA GQ structures.

MT3-MMP down-regulation promotes tumorigenesis and correlates to poor prognosis in esophageal squamous cell carcinoma.

The membrane-type matrix metalloproteinases (MT-MMPs) play an important role in degrading the extracellular matrix (ECM) and facilitating protease-dependent tumor progression and invasion. Here, we report that unlike MT1-MMP, MT3-MMP was down-regulated in esophageal squamous cell carcinoma (ESCC) as detected by real-time PCR (qPCR), Western blot analysis, and immunohistochemistry (IHC). Down-regulation of MT3-MMP was observed at protein level in 66.3% of ESCC specimens (by IHC, n = 86) for routine pathologic diagnosis, as well as at mRNA level in 63.3% of surgically resected ESCC tumors paired with surrounding nontumor tissues (by qPCR, n = 30). Notably, MT3-MMP down-regulation significantly correlated with lymph node metastasis and poor overall survival of patients with ESCC (median 5-year survival = 50.69 vs. 30.77 months for patients with MT3-MMP-negative and -positive ESCC, respectively). Mechanistically, MT3-MMP negatively regulated proliferation, colony formation, and migration of ESCC cells, in association with cell cycle arrest at G1, due to up-regulation of p21(Cip1) and p27(Kip1) . Together, as a tumor suppressor in ESCC, MT3-MMP down-regulation represents an unfavorable factor for prognosis of patients with ESCC.

Biochemical and spectroscopic characterization of the catalytic domain of MMP16 (cdMMP16).

Membrane-bound matrix metalloproteinase 16 (MMP16/MT3-MMP) is considered a drug target due to its role(s) in disease processes such as cancer and inflammation. Biochemical characterization of MMP16 is critical for developing new generation MMP inhibitors (MMPi), which exhibit high efficacies and selectivities. Herein, a modified over-expression and purification protocol was used to prepare the catalytic domain of MMP16 (cdMMP16). The resulting recombinant enzyme exhibited steady-state kinetic constants of K m = 10.6 ± 0.7 µM and k cat = 1.14 ± 0.02 s(-1), when using FS-6 as substrate, and the enzyme bound 1.8 ± 0.1 eq of Zn(II). The enzymatic activity of cdMMP16 is salt concentration-dependent, and cdMMP16 exhibits autoproteolytic activity under certain conditions, which may be related to an in vivo regulatory mechanism of MMP16 and of other membrane-type MMPs (MT-MMPs). Co(II)-substituted analogs (Co2- and ZnCo) of cdMMP16 were prepared and characterized using several spectroscopic techniques, such as UV-Vis, (1)H NMR, and EXAFS spectroscopies. A well-characterized cdMMP16 is now available for future inhibitor screening efforts.