MicroRNA 520d-3p inhibits gastric cancer cell proliferation,migration, and invasion by downregulating EphA2 expression

Aberrant expression of microRNAs (miRNAs) has been shown to play important roles in cancer progression as a result of changes in expression of their target genes. In this study, we investigated the roles of miR-520d-3p on gastric cancer (GC) cell proliferation, migration, and invasion, and confirmed that this miRNA regulates EphA2 expression. The mRNA expression levels of miR-520d-3p and EphA2 in GC tissues and cell lines were evaluated. The clinical and prognostic significance of miR-520d-3p was assessed. The biological function of miR-520d-3p in GC cells was investigated using a methylthiazolyldiphenyl-tetrazolium bromide assay, cell cycle assay, transwell invasion assay, and wound-healing assay. miR-520d-3p expression was down-regulated and inversely correlated with the expression of EphA2 in GC tissues and cell lines. Lower expression of miR-520d-3p was associated with tumor invasion (P = 0.0357), lymph nodes metastasis (P = 0.0272), a higher clinical stage (P = 0.0041), and poorer overall survival (P = 0.0105). Luciferase assays revealed that miR-520d-3p inhibited EphA2 expression by targeting the 3′-untranslated region of EphA2 mRNA. Overexpression of miR-520d-3p dramatically inhibited the proliferation, cell cycle progression, invasion, and migration of GC cells, while down-regulation substantially promoted these properties. Moreover, c-Myc, CyclinD1, and matrix metalloproteinase-9 expression levels were down-regulated in miR-520d-3p mimic-transfected cells and up-regulated in miR-520d-3p inhibitor-transfected cells. Taken together, our data showed that miR-520d-3p appears to contribute to GC progression via the regulation of EphA2 and could serve as a novel prognostic and potential therapeutic marker.     

Harmine induces apoptosis and inhibits tumor cell proliferation,migration and invasion through down-regulation of cyclooxygenase-2 expression in gastric cancer

Cyclooxygenase-2 (COX-2) plays an important role in the carcinogenesis and progression of gastric cancer. Harmine is reported as a promising drug candidate for cancer therapy; however, effects and action mechanism of harmine on the human gastric cancer cells remain unclear. This study evaluated the anti-tumor effects of harmine on human gastric cancer both in vitro and in vivo. The cell proliferation was determined using MTT colorimetric assay. Apoptosis was measured by DAPI staining and flow cytometry analysis. The wound healing and transwell invasion assays were performed to evaluate the effects of harmine on the migration and invasion of gastric cancer cells. The expression of COX-2, proliferating cell nuclear antigen (PCNA), Bcl-2, Bax and matrix metalloproteinase-2 (MMP-2) was detected by Western blot analysis. Our results showed that harmine significantly inhibited cellular proliferation, migration, invasion and induced apoptosis in vitro, as well as inhibited tumor growth in vivo. In addition, harmine significantly inhibited the expression of COX-2, PCNA, Bcl-2 and MMP-2 as well as increased Bax expression in gastric cancer cells. These results collectively indicate that harmine induces apoptosis and inhibits proliferation, migration and invasion of human gastric cancer cells, which may be mediated by down-regulation of COX-2 expression.     

Spondin 2 promotes the proliferation,migration and invasion of gastric cancer cells

Spondin 2 (SPON2), a member of the Mindin F‐Spondin family, identifies pathogens, activates congenital immunity and promotes the growth and adhesion of neurons as well as binding to their receptors, but its role in promoting or inhibiting tumour metastasis is controversial. Here, we investigated its expression levels and mechanism of action in gastric cancer (GC). Western blotting and GC tissue arrays were used to determine the expression levels of SPON2. ELISAs were performed to measure the serum levels of SPON2 in patients with GC. Two GC cell lines expressing low levels of SPON2 were used to analyse the effects of regulating SPON2 expression on proliferation, migration, invasion, the cell cycle and apoptosis. The results revealed that SPON2 was highly expressed in GC tissues from patients with relapse or metastasis. The levels of SPON2 in sera of patients with GC were significantly higher compared with those of healthy individuals and patients with atrophic gastritis. Knockdown of SPON2 expression significantly inhibited the proliferation, migration and invasion of GC cells in vitro and in vivo. Down‐regulation of SPON2 arrested the cell cycle in G1/S, accelerated apoptosis through the mitochondrial pathway and inhibited the epithelial‐mesenchymal transition by blocking activation of the ERK1/2 pathway. In summary, this study suggests that SPON2 acts as an oncogene in the development of GC and may serve as a marker for the diagnosing GC as well as a new therapeutic target for GC.     

p75 neurotrophin receptor inhibits invasion and metastasis of gastric cancer

The p75 neurotrophin receptor (p75NTR) is a focus for study at present. However, its function in gastric cancer was not elucidated. Here, we investigated its relation with metastasis of gastric cancer. By immunohistochemistry, we found that the positive rate of p75NTR expression in metastatic gastric cancer was 15.09% (16 of 106), which was lower compared with nonmetastatic gastric cancer (64.15%; 68 of 106). The average staining score in nonmetastatic gastric cancer was significantly higher than in metastatic gastric cancer (1.21 +/- 0.35 versus 0.23 +/- 0.18; P<0.01). p75NTR protein level was also lowly expressed in the highly liver-metastatic gastric cancer cell line XGC9811-L compared with other gastric cancer cell lines by Western blotting. It could also significantly inhibit the in vitro adhesive, invasive, and migratory and in vivo metastatic abilities of gastric cancer cell lines SGC7901 and MKN45 by reducing urokinase-type plasminogen activator (uPA) and matrix metalloproteinase (MMP)-9 proteins and by increasing tissue inhibitor of matrix metalloproteinase (TIMP)-1 protein. Further studies showed that p75NTR could suppress the nuclear factor-kappaB (NF-kappaB) signal. SN50, a specific inhibitor of NF-kappaB, which could inhibit in vitro invasive and migratory abilities of gastric cancer cells, reduced expression of uPA and MMP9 proteins and increased expression of TIMP1 protein. Taken together, p75NTR had the function of inhibiting the invasive and metastatic abilities of gastric cancer cells, which was mediated, at least partially, by down-regulation of uPA and MMP9 proteins and up-regulation of TIMP1 protein via the NF-kappaB signal transduction pathway. Our studies suggested that p75NTR may be used as a new potential therapeutic target in metastatic gastric cancer.     

Overexpression of long non-coding RNA RP11-363E7.4 inhibits proliferation and invasion in gastric cancer

LncRNA RP11-363E7.4 has been shown to be downregulated in gastric cancer (GC), while the effect of lncRNA RP11-363E7.4 on GC and its potential molecular mechanisms is unclear. The purpose of this study was to explore the functional role and underlying molecular mechanisms of lncRNA RP11-363E7.4 involved in GC progress.To address the question, quantitative real-time PCR assay was performed to confirm lncRNA RP11-363E7.4 expression levels in GC tissues and cell lines. Cell proliferation, apoptosis, migration and invasion were estimated using Cell Counting Kit-8, colony formation, scratch wound healing and Transwell assays. Potential molecular mechanisms were evaluated using western blot assay. The results showed that lncRNA RP11-363E7.4 was significantly downregulated in GC cell lines and 82 paired tissues. The correlation between expression and clinicopathological features indicated that low expression of lncRNA RP11-363E7.4 was associated with T stage (P = .010). Functional experiments showed that overexpression of lncRNA RP11-363E7.4 prevented proliferation, migration, and invasion and induced apoptosis of GC cells. Western blot assay revealed that lncRNA RP11-363E7.4 functioned via the p53, Bax/Bcl-2, β-catenin pathway. In summary, this study revealed that lncRNA RP11-363E7.4 functioned as a tumour suppressor by inhibiting proliferation, migration, and invasion and inducing apoptosis of GC cells. Significance of the study :LncRNA RP11-363E7.4 has been shown to be downregulated in GC, while the effect of lncRNA RP11-363E7.4 on GC and its potential molecular mechanism is unclear. We revealed that lncRNA RP11-363E7.4 functioned as a tumour suppressor by inhibiting proliferation, migration, and invasion and inducing apoptosis of GC cells. LncRNA RP11-363E7.4 might become an attractive diagnostic and prognostic biomarker of GC and a promising target for GC treatment.     

MicroRNA-185 suppresses proliferation, invasion, migration, and tumorigenicity of human prostate cancer cells through targeting androgen receptor

Previous studies have shown that androgen receptor (AR) is involved in the progression of prostate cancer (CaP) by several mechanisms. However, how AR is regulated has not been fully understood. In this study, miR-185 was found to be down-regulated in clinical CaP samples. Targets prediction revealed that AR had putative complementary sequences to miR-185, which was confirmed by the following dual luciferase reporter assay. Overexpression of miR-185 could reduce the expression of AR protein but not mRNA in LNCaP cells. The proliferation of LNCaP cells was inhibited by overexpression of miR-185. Cell cycle analysis revealed cell cycle arrest at G0/G1 phase. The invasive and migration abilities of cells could also be suppressed by miR-185. Furthermore, miR-185 inhibited tumorigenicity in a CaP xenografts model. CDC6, one target of AR and an important regulatory molecule for cell cycle, was found to be down-regulated by overexpression of miR-185. Our findings suggest that miR-185 could function as a tumor-suppressor gene in CaP by directly targeting AR, and act as a potential therapeutic target for CaP.     

Knockdown of LASP2 inhibits the proliferation,migration, and invasion of cervical cancer cells

LIM and SH3 protein 2 (LASP2) belongs to nebulin family. It has been proven that LASP2 is involved in several cancers; however, its role in cervical cancer is unclear. Herein, we showed that LASP2 was highly expressed in cervical cancer tissues and cell lines. To knockdown LASP2 in cervical cancer cells, small interfering RNAs (siRNAs) targeting LASP2 (si-LASP2) were used. We found that cell proliferation, migration/invasion were markedly reduced after si-LASP2 transfection. A significant increase in E-cadherin expression, and decrease in N-cadherin and vimentin expressions were observed in si-LASP2 transfected cervical cancer cells. Knockdown of LASP2 caused significant inhibitory effect on the PI3K/Akt pathway. Treatment with the activator of the PI3K/Akt pathway, 740Y-P, abolished the effects of si-LASP2 transfection on cervical cancer cells. These findings suggested that LASP2 may be an oncogene through regulating the PI3K/Akt pathway in cervical cancer.     

Silencing of FOXO6 inhibits the proliferation,invasion, and glycolysis in colorectal cancer cells

Forkhead box class O6 (FOXO6) is an important member of FOXO family, which has been demonstrated to be implicated in tumor development. However, the role of FOXO6 in colorectal cancer (CRC) is still unclear. The study aimed to investigate the potential roles of FOXO6 in the development of CRC. Our results showed that FOXO6 was overexpressed in CRC tissues and cell lines. FOXO6 knockdown inhibited cell proliferation, as well as repressed the migration and invasion of CRC cells. Additionally, we found that FOXO6 knockdown altered cellular metabolism by inhibiting glycolysis and promoting mitochondrial respiration. Furthermore, FOXO6 knockdown inhibited the activation of PI3K/Akt/mTOR pathway in CRC cells. The results herein indicated that FOXO6 knockdown inhibited cell proliferation, migration, invasion, and glycolysis in CRC cells. PI3K/Akt/mTOR pathway was involved in the effects of FOXO6 on CRC cells. These findings suggested that FOXO6 might be a potential target for the CRC therapy.     

Retracted: Curcumin derivative L6H4 inhibits proliferation and invasion of gastric cancer cell line BGC-823

Curcumin and its chalcone derivatives have well-known, explicit biological antitumor properties, such as instance antiproliferative and apoptotic effects via multiple molecular targets. In this study, we investigated the anticancer activity of curcumin derivative L6H4 (curcumin L6H4) on gastric cancer cells. Inhibitory effects of curcumin L6H4 on gastric cancer cells (BGC-823) were studied by the diphenyltetrazolium (MTT) assay, and cell apoptosis was detected by Annexin-V/propidium iodide (PI) staining and then analyzed by flow cytometry. A mouse xenotransplant gastric tumor model was established to detect the role of curcumin L6H4 in vivo. The apoptosis-related proteins p53, p21, Bax, and Bcl-2 in BGC-823 cells and mouse xenotransplant models treated with curcumin L6H4 were determined by Western blot analysis. Curcumin L6H4 can significantly inhibit the proliferation and induce the apoptosis of BGC-823 cells, thus enhancing the expression levels of p53, p21, Bax, and Bcl-2 noticeably in vivo and in vitro. Meanwhile, curcumin L6H4 can remarkably suppress the growth of tumor cells in animal models. These results suggest that curcumin derivative L6H4 has potent of antitumor properties in vitro or in vivo.     

STAM2 knockdown inhibits proliferation,migration,and invasion by affecting the JAK2/STAT3 signaling pathway in gastric cancer

Signal transducing adaptor molecule 2(STAM2)is a phosphotyrosine protein,which regulates receptor signaling and trafficking of mammalian cells.However,its role ...     

A novel metformin derivative,HL010183, inhibits proliferation and invasion of triple-negative breast cancer cells

Mounting evidence suggests that metformin (N,N-dimethylbiguanide), a widely prescribed drug for the treatment of type II diabetes, exerts an anti-tumor effect on several cancers including breast cancer. Breast cancer has been estimated as one of the most commonly diagnosed types of cancer among women. In particular, triple-negative breast cancers are associated with poor prognosis and metastatic growth. In the present study, we synthesized a novel metformin derivative 5 (HL010183) and metformin salts, 9a, 9b, and 9c (metformin gamma-aminobutyric acid (GABA) salt, metformin pregabalin salt and metformin gabapentin salt), which exerted more potent inhibitory effects on the proliferation and invasiveness of Hs578T triple-negative breast carcinoma cells than metformin. Importantly, 5 showed approximately 100-fold more potent effects compared to metformin. In a triple-negative breast cancer xenograft model, 5 showed a comparable degree of inhibitory effect on in vivo tumor growth at the 100 mg/kg dose to that of metformin at 500 mg/kg. Our results clearly demonstrate that 5 exerts a potent anti-tumor effect both in vitro and in vivo, paving the way for a strategy for treatment of triple-negative breast cancer.     

miR-206 inhibits thyroid cancer proliferation and invasion by targeting RAP1B

Thyroid cancer (TC) is one of the primary tumors arisen from endocrine system. The purpose of this study was to investigate the underlying mechanism by which RAP1B (Ras-related protein Rap-1b) modulates microRNA (miR)-206 related effects on TC cells. Expression of miR-206 and RAP1B was analyzed in cells and tissues. miR-206 mimics or inhibitors and RAP1B vector were used in functional experiments to investigate the effects of miR-206 and RAP1B on cell activities including proliferation, migration, and invasion. Luciferase assay was performed to explore the association between miR-206 and RAP1B. The influence of miR-206 on tumorigenesis of TC cells was investigated using an ex vivo model. Our results demonstrated the reduce of miR-206 in TC tissues and cell lines in which RAP1B was increased. Overexpression of miR-206 significantly inhibited the functional capacities of TPC-1 cells including proliferation, invasion, and migration, most likely, through reducing the expression of RAP1B. Xenograft experiment showed that increased miR-206 could effectively inhibit the tumorigenesis of TC cells. Our study showed that miR-206 negatively regulated cell activities of proliferation, invasion, and migration in TC via suppressing RAP1B expression, suggesting that miR-206 exerts a vital role in TC.     

Silencing ARHGAP9 correlates with the risk of breast cancer and inhibits the proliferation,migration, and invasion of breast cancer

Breast cancer (BC) is one of the most common malignant tumors in women, and screening relevant genes and markers that are involved in BC tumor genesis and progression is of great value. We previously found that messenger RNA expression of ARHGAP9 was high in BC tissue, but it is unclear whether ARHGAP9 participates in the progression of human BC. In this study, we found that ARHGAP9 expression was correlated with poor patient survival, American Joint Committee on Cancer clinical staging, tumor size, and tumor differentiation. MCF‐7 and MDA‐MB‐231 cells exhibited higher expression of ARHGAP9 than other human BC cell lines (HCC1937, MDA‐MB‐453, ZR‐75‐1, and Hs 578T). Knockdown of ARHGAP9 in human BC cells markedly reduced the cell proliferation, migration, and invasive ability of MCF‐7 and MDA‐MB‐231 cells. Furthermore, small interfering RNA (siRNA) of ARHGAP9 also induced G0‐G1 cell cycle arrest and apoptosis in MCF‐7 and MDA‐MB‐231 cells. Expressions of cell cycle markers (CDK2 and CCNB1) and invasion‐related protein (RhoC and MTA1) were downregulated in siRNA‐ARHGAP9‐transfected cells. siRNA of ARHGAP9 also inhibited the phosphorylation of mitogen‐activated protein kinases in BC cells. In conclusion, the abnormal expression of ARHGAP9 may correlate with the genesis, development, and diagnosis of BC.     

PTEN inhibits the invasion and metastasis of gastric cancer via downregulation of FAK expression

The tumor suppressor gene phosphatase and tensin homolog (PTEN) is essential in inhibiting tumor growth and metastasis. However, the mechanism by which PTEN restricts gastric cancer progression and metastasis remains largely elusive. Here we demonstrated that PTEN overexpression or knockdown in gastric cancer cells led to the downregulation or upregulation of focal adhesion kinase (FAK), and decreased or increased cell invasion, respectively. Moreover, FAK overexpression could rescue the inhibition of cell invasion by PTEN. These results were further confirmed in orthotropic gastric cancer nude mice model. In addition, in human gastric cancer tissues, PTEN protein level was conversely correlated with FAK protein level. Mechanistically, we found that PTEN inhibited PI3K/NF-κB pathway and inhibited the DNA binding of NF-κB on FAK promoter. Taken together, our data reveal a novel mechanism that PTEN inhibits the growth and invasion of gastric cancer via the downregulation of FAK expression and suggest that exploiting PTEN/PI3K/NF-κB/FAK axis is a promising approach to treat gastric cancer metastasis.