Functional variants of the pentraxin 3 gene are associated with the metastasis and progression of prostate cancer.

Age, ethnic background and genetic components have been identified as the established risks for prostate cancer (PCa). Pentraxin 3 (PTX3), originally identified as a pattern-recognition molecule for defence against infectious agents, has multiple functions in tissue repair and in the regulation of cancer-associated inflammation. In this study, we sought to investigate the impact of PTX3 gene variants on the development of PCa. Genotypes of four common single-nucleotide polymorphisms (SNPs) of PTX3 gene, including rs1840680, rs2305619, rs3816527 and rs2120243, were profiled among 705 PCa patients and 705 ethnicity-matched controls. In this study, we found that patients who carry at least one minor allele (C) of rs3816527 (AC and CC) tended to develop advanced forms of diseases (clinical large T stage, OR, 1.593, p = 0.032; pathologically-confirmed nodal spread, OR, 1.987, p = 0.011; metastatic tumour, OR, 3.896, p = 0.032) as compared with those homologous for the major allele (AA). Further stratification analysis showed that such association of rs3816527 with lymphatic and distal metastasis of PCa was accentuated in the younger age group (≤65 at diagnosis) but not seen in the older age group (>65 at diagnosis), suggesting an age-specific effect of PTX3 variants. Prediction of PTX3 protein structure implied that polymorphism may alter the quaternary organization and oligomerization of PTX3 protein. Moreover, our gene silencing experiments and survey of public datasets revealed that elevation of PTX3 levels in PCa was required for cell migration and associated with tumour metastasis. Our results highlight an association of PTX3 rs3816527 with the progression of PCa.

MAOB expression correlates with a favourable prognosis in prostate cancer, and its genetic variants are associated with the metastasis of the disease.

Monoamine oxidase B (MAOB), a neurotransmitter-degrading enzyme, was reported to reveal conflicting roles in various cancers. However, the functional role of MAOB and impacts of its genetic variants on prostate cancer (PCa) is unknown. Herein, we genotyped four loci of MAOB single-nucleotide polymorphisms (SNPs), including rs1799836 (A/G), rs3027452 (G/A), rs6651806 (A/C) and rs6324 (G/A) in 702 PCa Taiwanese patients. We discovered that PCa patients carrying the MAOB rs6324 A-allele exhibited an increased risk of having a high initial prostate-specific antigen (iPSA) level (>10 ng/mL). Additionally, patients with the rs3027452 A-allele had a higher risk of developing distal metastasis, particularly in the subpopulation with high iPSA levels. In a subpopulation without postoperative biochemical recurrence, patients carrying the rs1799836 G-allele had a higher risk of developing lymph node metastasis and recurrence compared to those carrying the A-allele. Furthermore, genotype screening in PCa cell lines revealed that cells carrying the rs1799836 G-allele expressed lower MAOB levels than those carrying the A-allele. Functionally, overexpression and knockdown of MAOB in PCa cells respectively suppressed and enhanced cell motility and proliferation. In clinical observations, correlations of lower MAOB expression levels with higher Gleason scores, advanced clinical T stages, tumour metastasis, and poorer prognosis in PCa patients were noted. Our findings suggest that MAOB may act as a suppressor of PCa progression, and the rs3027452 and rs1799836 genetic variants of MAOB are linked to PCa metastasis within the Taiwanese population.

Corosolic acid inhibits metastatic response of human renal cell carcinoma cells by modulating ERK/MMP2 signaling.

Corosolic acid (CA), a plant-derived pentacyclic triterpenoid, has potent anti-inflammatory, anti-metabolic, and anti-neoplastic actions against a variety of human cancers. However, the specific mechanism by which CA inhibits the progression of renal cell carcinoma (RCC) is yet unclear. We found that CA (≤8 µM) had no influence on either the growth or viability of RCC cell lines (786-O, ACHN, and Caki-1) or normal HK2 cells. However, in a dose-dependent manner, CA prevented the invasion and migration of RCC cells. Human protease array analysis showed that CA reduced MMP2 expression. At increasing concentrations of CA, the expression of MMP2 was dose-dependently reduced, as shown by western blot and RT-PCR analyses as well as immunofluorescence staining. CA also stimulated ERK1/2 phosphorylation in 786-O and Caki-1 cells. Transfection of CA-treated RCC cells with siRNA-ERK restored MMP2 protein expression and the motility and invasion capabilities of RCC cells. Molecular docking study results showed that CA and MMP2 interact strongly. These findings elucidate the mechanism by which CA prevents RCC cells from migrating and invading, and these findings indicate that CA may be a potential anti-metastatic therapy for RCC.

HO-3867, a curcumin analog, elicits cell apoptosis and p38-mediated caspase activation in hepatocellular carcinoma.

HO-3867, a synthetic curcumin analog, has displayed various tumor-suppressive characteristics and improved bioabsorption over its parent compound. However, its influences on the development of hepatocellular carcinoma (HCC) are poorly defined. To address this, we tested the anticarcinogenic impact of HO-3867 and investigated the underlying mechanisms in fighting liver cancer. Our result demonstrated that HO-3867 reduced the viability of HCC cells, accompanied by promotion of cell cycle arrest at the sub-G1 stage and apoptotic responses. Furthermore, a distinctive profile of apoptosis associated proteins, encompassing elevated heme oxygenase-1 (HO-1) level and caspase activation, was detected in HO-3867-stimulated HCC cells. In addition, such HO-3867-mediated elevation in caspase activation was dampened by pharmacological suppression of p38 activities. Taken together, our findings unveiled that HO-3867 triggered cell cycle arrest and apoptotic events in liver cancer, involving a p38-mediated activation of caspase cascades. These data highlighted a usefulness of curcumin or its analogs on the management of hepatocarcinogenesis.

Loss of MTA2-mediated downregulation of PTK7 inhibits hepatocellular carcinoma metastasis progression by modulating the FAK-MMP7 axis.

The expression of metastasis tumor-associated protein 2 (MTA2) and protein tyrosine kinase 7 (PTK7) is associated with hepatocellular carcinoma (HCC) progression. However, the functional effect and mechanism through which MTA2 regulates PTK7-mediated HCC progression remains unclear. Here, we found that MTA2 knockdown significantly down-regulated PTK7 expression in HCC cells (SK-Hep-1 and PLC/PRF/5). Data from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases show that the PTK7 expression level was higher in HCC tissues than in normal liver tissues. In HCC patients, the PTK7 expression level clearly correlated with tumor stage and grade, lower overall survival (OS) correlated positively with MTA2 level, and PTK7 expression acted as a downstream factor for MTA2 expression. In addition, matrix metalloproteinase 7 (MMP7) expression was closely regulated by PTK7, and the mRNA and protein expression levels of MTA2 and PTK7 correlated positively with lower OS. MMP7 downregulation by PTK7 knockdown clearly decreased the migration and invasion abilities of HCC cells. In HCC cells, recombinant human MMP7 reversed the PTK7 knockdown-induced suppression of migration and invasion. Furthermore, deactivation of FAK using siFAK or FAK inhibitor (PF-573228, PF) synergistically contributed to PTK7 knockdown-inhibited FAK activity, MMP7 expression, and the migration and invasion abilities of HCC cells. Collectively, our findings show that PTK7 mediates HCC progression by regulating the MTA2-FAK-MMP7 axis and may be a diagnostic value for HCC patients.

Sorafenib, a Tyrosine Kinase Inhibitor, Synergistically Enhances the Ferroptosis Effects of Asiatic Acid in Hepatocellular Carcinoma Cells.

Hepatocellular carcinoma (HCC) remains one of the most common cancers worldwide. Asiatic acid (AA) is a natural triterpene, which is recognized as effect of antioxidant and antitumor. Sorafenib (Sor), an orally target drug, has been applicate for the HCC therapy. However, the synergistic effect of AA and Sor on human HCC is still unclear. Here, we explore the effect of combined treatment with AA and Sor in the HCC cell line SK-HEP-1 and HepG2. Compared with treating alone, our results demonstrated that AA combined with Sor synergistically inhibited proliferative rates in MTT assay and colony formation assay. We also found that AA combined with Sor in HCC cells strongly caused cell cycle arrest in G0/G1 phase and affected the protein level of cyclin D1 and SKP2. Furthermore, combination treatment strongly enhanced ferroptosis through cellular accumulation of iron ions, lipid peroxidation, and ferroptosis-related proteins (GPX4 and FTH1) in HCC cells. In addition, the combined treatment resulted in higher phosphorylation of JNK1/2 in the promotion of ferroptosis than drug treatment alone. These results indicate that AA combined with Sor synergistically improved ferroptosis in HCC cells through the regulation of JNK1/2 signaling. Taken together, the combinatorial strategy may serve as the potential treatment in HCC.

Tricetin suppresses the cell migration and BMP-6 expression through p38 signaling pathways in human retinal pigment epithelium cells.

Proliferative vitreoretinopathy (PVR) is a visual-threatening disease, which cause from the migration of retinal pigment epithelium (RPE). Tricetin, a family of flavonoids, can inhibit the metastasis of several cancers. Herein, we aim to evaluate the possible effect of tricetin on inhibiting ARPE-19 cells migration. The Boyden chamber assay, wound healing assay, RNA sequencing, and Western blot analysis were applied in our experiment. The results revealed that tricetin inhibited the cell migration abilities of ARPE-19 cells. Moreover, using RNA sequencing technology, we revealed that tricetin repressed bone morphogenetic protein-6 (BMP-6) gene expressions in ARPE-19 cells. Overexpression of BMP-6 resulted in significant restoration of cell migration capabilities of tricetin-treated ARPE-19 cells. Furthermore, tricetin suppressed the phosphorylation of the p38 signaling pathway. Moreover, blocking the p38 pathway also inhibits BMP-6 expression and migration in the ARPE-19 cells. In conclusion, this study revealed that tricetin inhibits the ARPE-19 cell migration mainly via the suppression of BMP-6 expression and p38 signaling pathway.

Morin inhibits osteosarcoma migration and invasion by suppressing urokinase plasminogen activator through a signal transducer and an activator of transcription 3.

Osteosarcoma, the most common primary bone cancer that affects adolescents worldwide, has the early metastatic potential to be responsible for high mortality rates. Morin has a multipurpose role in numerous cancers, whereas little is known about its role in osteosarcoma migration and invasion. Therefore, we hypothesized that morin suppresses the invasive activities and the migratory potential of human osteosarcoma cells. Our results showed that morin reduced migration and invasion capabilities in human osteosarcoma U2OS and HOS cells. Moreover, morin inhibited the urokinase plasminogen activator (uPA) expression through a signal transducer and an activator of transcription-3 (STAT3) phosphorylation. After STAT3 overexpression, the decrease of the migratory potential and uPA expression caused by 100 µM of morin in U2OS cells was countered, indicating that STAT3 contributes to the antimetastatic property of morin in human osteosarcoma cells by reducing uPA. In conclusion, morin may be a potential candidate for the antimetastatic treatment of human osteosarcoma.

Asiatic acid inhibits osteosarcoma cell migration and invasion via the AKT/Sp1/MMP1 axis.

Osteosarcoma is a malignant bone tumor affecting adolescents and children. No effective treatment is currently available. Asiatic acid (AA), a triterpenoid compound found in Centella asiatica, possesses anti-tumor, anti-inflammatory, and anti-oxidant properties in various types of tumor cells. This study aims to determine whether AA exerts antitumor effects in human osteosarcoma cells. Our results indicate that AA does not influence the viability, proliferative rate, or cell cycle phase of human osteosarcoma cells under non-toxic conditions. AA suppressed osteosarcoma cell migration and invasion by down-regulating matrix metalloproteinase 1 (MMP1) expression. Data in the TNMplot database suggested MMP1 expression was higher in osteosarcoma than in normal tissues, with associated clinical significance observed in osteosarcoma patients. Overexpression of MMP1 in osteosarcoma cells reversed the AA-induced suppression of cell migration and invasion. AA treatment decreased the expression of specificity protein 1 (Sp1), while Sp1 overexpression abolished the effect of AA on MMP1 expression and cell migration and invasion. AA inhibited AKT phosphorylation, and treatment with a PI3K inhibitor (wortmannin) increased the anti-invasive effect of AA on osteosarcoma cells via the p-AKT/Sp1/MMP1 axis. Thus, AA exhibits the potential for use as an anticancer drug against human osteosarcoma.

The Anti-Metastatic Action of Oxyresveratrol via Suppression of Phosphoryl-ERK/-PKCα-Mediated Sp1/MMP1 Signaling in Human Renal Carcinoma Cells.

Oxyresveratrol (OxyR) exerts biological and pharmacological effects in a variety of tumor cells, including antioxidant action, antitumor activity, and proapoptotic effects. However, the regulation of targeted signaling pathways by OxyR and the mechanism underlying these effects in human renal cell carcinoma (RCC) have been less studied. We observed that OxyR at noncytotoxic doses did not affect the growth of human RCC cells or normal kidney HK2 cells. OxyR inhibited ACHN and Caki-1 cell migration and invasion through targeting matrix metalloproteinase 1 (MMP1) expression. Analysis of clinical databases showed that high MMP1 expression is associated with lower overall survival (OS) in these cancers (p < 0.01). OxyR significantly inhibited the mRNA and protein expression of Sp1. Furthermore, luciferase assay results showed that OxyR inhibited Sp1 transcriptional activity. Additionally, OxyR preferentially suppressed the activation of ERK and PKCα. Treatment with U0126 (MEK inhibitor) or G06976 (PKCα inhibitor) clearly decreased Sp1 and MMP1 expression and inhibited RCC cell migration and invasion. In conclusion, OxyR may be a potential antitumor therapy for the inhibition of migration and invasion by controlling p-ERK/Sp1 and p-PKCα/Sp1-mediated MMP1 expression in RCC.

Licochalcone A induces endoplasmic reticulum stress-mediated apoptosis of endometrial cancer cells via upregulation of GRP78 expression.

Licochalcone A (LicA), a natural compound extracted from licorice root, has been shown to exert a variety of anticancer activities. Whether LicA has such effects on endometrial cancer (EMC) is unclear. This study aims to investigate the antitumor effects of LicA on EMC. Our results show that LicA significantly reduced the viability and induced apoptosis of EMC cells and EMC-7 cells from EMC patients. LicA was also found to induce endoplasmic reticulum (ER) stress, leading to increased expression of ER-related proteins (GRP78/PERK/IRE1α/CHOP) in EMC cell lines. Suppression of GRP78 expression in human EMC cells treated with LicA significantly attenuated the effects of LicA, resulting in reduced ER-stress mediated cell apoptosis and decreased expression of ER- and apoptosis-related proteins. Our findings demonstrate that LicA induces apoptosis in EMC cells through the GRP78-mediated ER-stress pathway, emphasizing the potential of LicA as an anticancer therapy for EMC.

Apoptotic effect and cell arrest of deoxyshikonin in human osteosarcoma cells through the p38 pathway.

Osteosarcoma is the most common primary bone cancer that affects adolescents with early metastatic potential and drastically reduces their long-term survival rate if pulmonary metastases are detected at diagnosis. The natural naphthoquinol compound deoxyshikonin exhibits anticancer properties, so we hypothesized that it has an apoptotic effect on osteosarcoma U2OS and HOS cells and studied its mechanisms. After deoxyshikonin treatment, dose-dependent decreases in cell viability, induction of cell apoptosis and arrest in the sub-G1 phase of U2OS and HOS cells were observed. The increases in cleaved caspase 3 expression and the decreases in X-chromosome-linked IAP (XIAP) and cellular inhibitors of apoptosis 1 (cIAP-1) expressions after deoxyshikonin treatment in the human apoptosis array were identified in HOS cells, and dose-dependent expression changes of IAPs and cleaved caspase 3, 8 and 9 were verified by Western blotting in U2OS and HOS cells. Phosphorylation of extracellular signal-regulated protein kinases (ERK)1/2, c-Jun N-terminal kinases (JNK)1/2 and p38 expressions in U2OS and HOS cells was also increased by deoxyshikonin in a dose-dependent manner. Subsequently, cotreatment with inhibitors of ERK (U0126), JNK (JNK-IN-8) and p38 (SB203580) was performed to show that p38 signalling is responsible for deoxyshikonin-induced apoptosis in U2OS and HOS cells, but not via the ERK and JNK pathways. These discoveries demonstrate that deoxyshikonin may be a possible chemotherapeutic candidate to induce cell arrest and apoptosis by activating extrinsic and intrinsic pathways through p38 for human osteosarcoma.

Induction of immunogenic cell death effect of licoricidin in cervical cancer cells by enhancing endoplasmic reticulum stress-mediated high mobility group box 1 expression.

Licoricidin (LCD) is an activity compound of the roots of Glycyrrhiza uralensis, which has therapeutic efficacy, including anti-virus, anti-cancer, and enhanced immunity in Traditional Chinese Medicine. Herein, this study aimed to clarify the effect of LCD on cervical cancer cells. In the present study, we found that LCD significantly inhibited cell viability via inducing cell apoptosis and companies with cleaved-PARP protein expression and caspase-3/-9 activity. Cell viability was markedly reversed these effects by pan-caspase inhibitor Z-VAD-FMK treatment. Furthermore, we showed that LCD-induced ER (endoplasmic reticulum) stress triggers upregulating the protein level of GRP78 (Bip), CHOP, and IRE1α, and subsequently confirmed the mRNA level by quantitative real-time polymerase chain reaction. In addition, LCD exhibited the release of danger-associated molecular patterns from cervical cancer cells, such as the release of high-mobility group box 1 (HMGB1), secretion of ATP, and exposure of calreticulin (CRT) on the cell surface, which led to immunogenic cell death (ICD). These results provide a novel foundation that LCD induces ICD via triggering ER stress in human cervical cancer cells. LCD might be an ICD inducer of immunotherapy in progressive cervical cancer.

Involvement of matrix metalloproteinase 1 and urokinase-type plasminogen activator in the PKCα-p38 MAPK pathway-mediated progression of human liver cancer cells.

Our previous studies have shown that the plasminogen activator (PA) and matrix metalloproteinases (MMPs) proteinase systems were highly expressed in highly malignant liver cancer cells and regulated by PKCα. This study investigates whether the PKCα regulation of PA and MMPs systems is conducted through p38 mitogen-activated protein kinase (MAPK) signaling and the pathway is responsible for promoting cell progression. We found that the expressions of p38 MAPK in both highly malignant HA22T/VGH and SK-Hep-1 liver cancer cells were higher than that in other lower malignancy liver cancer cells. Since PKCα activates p38 MAPK in progression of liver cancer, we suspected the PKCα/p38 MAPK signaling pathway to be involved in the regulation of MMPs and PA systems. When SK-Hep-1 cells were treated with SB203580 or DN-p38, only MMP-1 and u-PA mRNA expressions decreased. The p38 MAPK inhibition also decreased the cell migration and invasion. In addition, the mRNA decay assays showed that the higher expressions of MMP-1 and u-PA mRNA in SK-Hep-1 cells were due to the alteration of mRNA stability by p38 MAPK inhibition. Zymography of SK-Hep-1 cells treated with siPKCα vector also showed the decrease of the activity of MMP-1 and u-PA and confirmed changes in mRNA level. Furthermore, only the transfection of MKK6 to the siPKCα-treated SK-Hep-1 stable clone cell restored the attenuation of MMP-1 and u-PA expressions. The treatment of SK-Hep-1 cells with either inhibitor of MMP-1 or u-PA reduced migration, and the reduction was enhanced with both inhibitors. In addition, tumorigenesis was also reduced with both inhibitors. These data suggest a novel finding that MMP-1 and u-PA are critical components in PKCα/MKK6/p38 MAPK signaling pathway which mediates liver cancer cell progression, and that the targeting of both genes may be a viable approach in liver cancer treatment.

Curcumin analog HO-3867 triggers apoptotic pathways through activating JNK1/2 signalling in human oral squamous cell carcinoma cells.

Human oral squamous cell carcinoma (OSCC) is the common head and neck malignancy in the world. While surgery, radiotherapy and chemotherapy are emerging as the standard treatment for OSCC patients, the outcome is limited to the recurrence and side effects. Therefore, patients with OSCC require alternative strategies for treatment. In this study, we aimed to explore the therapeutic effect and the mode of action of the novel curcumin analog, HO-3867, against human OSCC cells. We analysed the cytotoxicity of HO-3867 using MTT assay. In vitro mechanic studies were performed to determine whether MAPK pathway is involved in HO-3867 induced cell apoptosis. As the results, we found HO-3867 suppressed OSCC cells growth effectively. The flow cytometry data indicate that HO-3867 induce the sub-G1 phase. Moreover, we found that HO-3867 induced cell apoptosis by triggering formation of activated caspase 3, caspase 8, caspase 9 and PARP. After dissecting MAPK pathway, we found HO-3867 induced cell apoptosis via the c-Jun N-terminal kinase (JNK)1/2 pathway. Our results suggest that HO-3867 is an effective anticancer agent as its induction of cell apoptosis through JNK1/2 pathway in human oral cancer cells.

Targeting of Mcl-1 Expression by MiRNA-3614-5p Promotes Cell Apoptosis of Human Prostate Cancer Cells.

MicroRNA (miRNA) acts as a critical regulator of growth in various human malignancies. However, the role of miRNA-3614 in the progression of human prostate cancer remains unknown. In this study, our results demonstrated that miRNA-3614-5p exerts a significant inhibitory effect on cell viability and colony formation and induces sub-G1 cell cycle arrest and apoptosis in human prostate cancer cells. Myeloid cell leukemia-1 (Mcl-1) acts as a master regulator of cell survival. Using the miRNA databases, miRNA-3614-5p was found to regulate Mcl-1 expression by targeting positions of the Mcl-1-3' UTR. The reduction of Mcl-1 expression by miRNA-3614-5p was further confirmed using an immunoblotting assay. Pro-apoptotic caspase-3 and poly (ADP-ribose) polymerase (PARP) were significantly activated by miRNA-3614-5p to generate cleaved caspase-3 (active caspase-3) and cleaved PARP (active PARP), accompanied by the inhibited Mcl-1 expression. These findings were the first to demonstrate the anti-growth effects of miRNA-3614-5p through downregulating Mcl-1 expression in human prostate cancer cells.

Niclosamide Suppresses Migration and Invasion of Human Osteosarcoma Cells by Repressing TGFBI Expression via the ERK Signaling Pathway.

Osteosarcoma is a highly common malignant bone tumor. Its highly metastatic properties are the leading cause of mortality for cancer. Niclosamide, a salicylanilide derivative, is an oral antihelminthic drug of known anticancer potential. However, the effect of niclosamide on osteosarcoma cell migration, invasion and the mechanisms underlying have not been fully clarified. Therefore, this study investigated niclosamide's underlying pathways and antimetastatic effects on osteosarcoma. In this study, U2OS and HOS osteosarcoma cell lines were treated with niclosamide and then subjected to assays for determining cell migration ability. The results indicated that niclosamide, at concentrations of up to 200 nM, inhibited the migration and invasion of human osteosarcoma U2OS and HOS cells and repressed the transforming growth factor beta-induced protein (TGFBI) expression of U2OS cells, without cytotoxicity. After TGFBI knockdown occurred, cellular migration and invasion behaviors of U2OS cells were significantly reduced. Moreover, niclosamide significantly decreased the phosphorylation of ERK1/2 in U2OS cells and the combination treatment of the MEK inhibitor (U0126) and niclosamide resulted in the intensive inhibition of the TGFBI expression and the migratory ability in U2OS cells. Therefore, TGFBI derived from osteosarcoma cells via the ERK pathway contributed to cellular migration and invasion and niclosamide inhibited these processes. These findings indicate that niclosamide may be a powerful preventive agent against the development and metastasis of osteosarcoma.

New insights into antimetastatic signaling pathways of melatonin in skeletomuscular sarcoma of childhood and adolescence.

Melatonin is an indole produced by the pineal gland at night under normal light or dark conditions, and its levels, which are higher in children than in adults, begin to decrease prior to the onset of puberty and continue to decline thereafter. Apart from circadian regulatory actions, melatonin has significant apoptotic, angiogenic, oncostatic, and antiproliferative effects on various cancer cells. Particularly, the ability of melatonin to inhibit skeletomuscular sarcoma, which most commonly affects children, teenagers, and young adults, is substantial. In the past few decades, the vast majority of references have focused on the concept of epithelial-mesenchymal transition involvement in invasion and migration to allow carcinoma cells to dissociate from each other and to degrade the extracellular matrix. Recently, researchers have applied this idea to sarcoma cells of mesenchymal origin, e.g., osteosarcoma and Ewing sarcoma, with their ability to initiate the invasion-metastasis cascade. Similarly, interest of the effects of melatonin has shifted from carcinomas to sarcomas. Herein, in this state-of-the-art review, we compiled the knowledge related to the molecular mechanism of antimetastatic actions of melatonin on skeletomuscular sarcoma as in childhood and during adolescence. Utilization of melatonin as an adjuvant with chemotherapeutic drugs for synergy and fortification of the antimetastatic effects for the reinforcement of therapeutic actions are considered.

Demethoxycurcumin inhibits the cell migration and MMP-2 expression in human retinal pigment epithelial cells by targeting the STAT-3 pathway.

Proliferative vitreoretinopathy (PVR) involves retinal pigment epithelium (RPE) cell proliferation and migration and leads to tractional retinal detachment. Demethoxycurcumin (DMC), a curcuminoid, has anti-inflammatory and anti-tumour properties. However, whether DMC affects the migration of RPE cells and the molecular mechanism of human PVR remains unclear. The aim of the current study was to investigate the effects of DMC on the inhibition of migration and proteinase expression of human ARPE-19 cells. Herein, we provided molecular evidence associated with PVR prevention through DMC by inhibiting ARPE-19 cell migration. We performed gelatin zymography, Western blot and RT-PCR and respectively found that DMC is sufficient to reduce matrix metalloproteinase-2 (MMP-2) activity, protein level and mRNA expression. DMC suppressed the nuclear levels of transcriptional factors specificity protein 1 and c-Fos, which are involved in the modulation of the transcriptional activation of the MMP-2 gene. DMC also inhibited STAT-3 phosphorylation in ARPE-19 cells. Selective STAT-3 induction by a STAT-3 activator, colivelin, reverted MMP activity and protein expression and cell migration, which were reduced in response to DMC. The results proved the inhibitory effect of DMC on RPE cell migration and MMP-2 expression by the down-regulation of the STAT-3 signalling pathway.

A novel melatonin-regulated lncRNA suppresses TPA-induced oral cancer cell motility through replenishing PRUNE2 expression.

The inhibitory effect of melatonin on cancer cell dissemination is well established, yet the functional involvement of lncRNAs in melatonin signaling remains poorly understood. In this study, we identified a melatonin-attenuated lncRNA acting as a potential melatonin-regulated oral cancer stimulator (MROS-1). Downregulation of MROS-1 by melatonin suppressed TPA-induced oral cancer migration through replenishing the protein expression of prune homolog 2 (PRUNE2), which functioned as a tumor suppressor in oral cancer. Melatonin-mediated MROS-1/PRUNE2 expression and cell motility in oral cancer were regulated largely through the activation of JAK-STAT pathway. In addition, MROS-1, preferentially localized in the nuclei, promoted oral cancer migration in an epigenetic mechanism in which it modulates PRUNE2 expression by interacting with a member of the DNA methylation machinery, DNA methyltransferase 3A (DNMT3A). Higher methylation levels of PRUNE2 promoter were associated with nodal metastases and inversely correlated with PRUNE2 expression in head and neck cancer. Collectively, these findings suggest that MROS-1, serving as a functional mediator of melatonin signaling, could predispose patients with oral cancer to metastasize and may be implicated as a potential target for antimetastatic therapies.