Inhibits Tumor Invasion Research Articles

Epigallocatechin‑3‑gallate inhibits the invasion of salivary adenoid cystic carcinoma cells by reversing the hypermethylation status of the RECK gene.

Epigallocatechin‑3‑gallate (EGCG) is an active and major constituent of green tea. As a non‑nucleoside inhibitor of DNA methylation, EGCG is able to inhibit the hypermethylation of newly synthesised DNA, resulting in the reversal of hypermethylation and recovery in expression of the silenced genes. Reversion‑inducing cysteine‑rich protein with Kazal motifs (RECK) is a novel tumour suppressor gene, which negatively regulates matrix metalloproteinases, and inhibits tumour invasion, angiogenesis and metastasis. The present study aimed to examine the effects of EGCG on the methylation status of the RECK gene and tumour invasion in a salivary adenoid cystic carcinoma (SACC) cell line in vitro. Marked levels of methylated and weak levels of unmethylated RECK promoter were detected in the SACC83 cells, which was determined using methylation‑specific polymerase chain reaction (PCR). In addition, the treatment of SACC83 cells with EGCG partially reversed the hypermethylation status of the RECK gene. Western blot analysis and reverse transcription‑PCR demonstrated that EGCG significantly enhanced the protein and mRNA expression levels of RECK, and significantly reduced the invasive ability of the SACC83 cells, as determined using a Transwell assay. These results suggested that EGCG possesses novel anti‑metastatic therapeutic potential for the treatment of SACC.

Biodegradable interstitial release polymer loading a novel small molecule targeting Axl receptor tyrosine kinase and reducing brain tumour migration and invasion.

Glioblastoma multiforme (GBM) is the most common and aggressive brain tumour. The neoplasms are difficult to resect entirely because of their highly infiltration property and leading to the tumour edge is unclear. Gliadel wafer has been used as an intracerebral drug delivery system to eliminate the residual tumour. However, because of its local low concentration and short diffusion distance, patient survival improves non-significantly. Axl is an essential regulator in cancer metastasis and patient survival. In this study, we developed a controlled-release polyanhydride polymer loading a novel small molecule, n-butylidenephthalide (BP), which is not only increasing local drug concentration and extending its diffusion distance but also reducing tumour invasion, mediated by reducing Axl expression. First, we determined that BP inhibited the expression of Axl in a dose- and time-dependent manner and reduced the migratory and invasive capabilities of GBM cells. In addition, BP downregulated matrix metalloproteinase activity, which is involved in cancer cell invasion. Furthermore, we demonstrated that BP regulated Axl via the extracellular signal-regulated kinases pathway. Epithelial-to-mesenchymal transition (EMT) is related to epithelial cells in the invasive migratory mesenchymal cells that underlie cancer progression; we demonstrated that BP reduced the expression of EMT-related genes. Furthermore, we used the overexpression of Axl in GBM cells to prove that Axl is a crucial target in the inhibition of GBM EMT, migration and invasion. In an in vivo study, we demonstrated that BP inhibited tumour growth and suppressed Axl expression in a dose-dependent manner according to a subcutaneous tumour model. Most importantly, in an intracranial tumour model with BP wafer in situ treatment, we demonstrated that the BP wafer not only significantly increased the survival rate but also decreased Axl expression, and inhibited tumour invasion. These results contribute to the development of a BP wafer for a novel therapeutic strategy for treating GBM invasion and increasing survival in clinical subjects.

Expression and role of NGX6 in tumor

NGX6 is a recently discovered tumor-suppressor gene, which can inhibit tumor invasion and metastasis via suppressing tumor angiogenesis and lymphangiogenesis. The expression of NGX6 gene has negative correlation with many tumors, such as nasopharyngeal carcinoma, lung cancer, colon cancer and so on. Therefore, the measurement of NGX6′s level has a great influence on the prognosis of patients with tumor. Key words: Neoplasms; Neoplasm metastasis; Nasopharyngeal carcinoma-associated gene 6

Abstract 4653: Modulation of mTOR and p53 signaling using rapamycin plus CP-31398 inhibits growth and progression of urothelial carcinoma in-vivo

Abstract Bladder cancer is the second most common genitourinary cancer worldwide. Despite multidisciplinary treatment advances, muscle-invasive bladder cancer continues to have high mortality. Since dysregulation of p53 and mTOR signaling in urothelium is associated with tumor initiation, growth and invasiveness, we investigated whether up-regulation of TP53 plus inhibition of mTOR additively or synergistically inhibits tumor growth and progression in vivo. Transgenic UPII-SV40T male mice (n = 15/group) were generated, genotyped and fed control or experimental diets containing the mTOR inhibitor rapamycin (8 or 16 ppm) and/or the p53 stabilizing agent CP31398 (150 ppm) starting at 6 weeks of age. After 34 weeks, control diet fed transgenic mice developed urothelium-specific high-grade, invasive transitional cell carcinoma (TCC) with significant increase in bladder weights (140.2 ± 9.8 mg; p<0.0001) compared with wild type (27.3 ± 0.8 mg). Rapamycin (8 or 16 ppm) reduced tumor weight by ∼ 67% or 77% and CP31398 decreased it by >70%. The combination of CP31398 with 8 ppm rapamycin decreased tumor weight by ∼83% (16.47 ± 5.4 mg; p<0.0001). Rapamycin (8 or 16 ppm) suppressed tumor invasion by 53% (p<0.005) or 66% (p<0.0005). CP-31398 alone failed to inhibit tumor invasion; however its combination with low-dose rapamycin inhibited tumor invasion >71% (p<0.0001). Molecular analysis of tumors via real-time PCR, IHC and western blotting showed synergistic inhibition by the drug combination of tumor growth and invasion with suppression of mTOR signaling (mTOR, pmTOR, raptor, rictor, Akt, pAkt); induction of p53 expression; and decreased expression of proliferation (PCNA), cell cycle regulators (cyclin D1, cyclin A), pro-survival molecules (Hif1a, Vegf) and androgen receptor. The combination of CP-31398 and rapamycin appears to be a promising approach for preventing urothelial TCC invasion. (Supported in part by NCI-CN53300) Note: This abstract was not presented at the meeting. Citation Format: Venkateshwar Madka, Altaf Mohammed, Qian Li, Yuting Zhang, Laura Biddick, Jagan M.R. Patlolla, Stanley Lightfoot, Xue-Ru Wu, Vernon Steele, Levy Kopelovich, Chinthalapally V. Rao. Modulation of mTOR and p53 signaling using rapamycin plus CP-31398 inhibits growth and progression of urothelial carcinoma in-vivo. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4653. doi:10.1158/1538-7445.AM2015-4653

Abstract 1447: Functional genomics identifying a TIS1-HIF-NOTCH signaling orchestrating epithelial-mesenchymal transition for tumor invasion

Abstract Human hepatocellular carcinoma (HCC) is characterized by frequent local invasion and recurrence, which are strongly associated with poor overall survival of HCC patients. Epithelial-mesenchymal transition (EMT) is an initiating event driving tumour invasion and metastasis. However, the molecular mechanisms of EMT in HCC remains largely unknown. We have performed a human kinome/phosphatome RNAi screen to identify novel genes that are involved in invasion and metastasis of HCC cells using Hep3B, a low motile HCC cell line, and identified TIS1 (Tumor Invasion Suppressor 1) as a potential cell motility suppressor. Mechanistic studies revealed that TIS1 was a novel actin binding protein that sequestrated globular actins and prevented actin filament (F-actin) formation, thereby suppressing the formation of filopodia, lamillepodia and invadopodia. Silencing of TIS1 enhanced EMT and tumor cell migration and invasion. Notably, F-actin polymerization induced by TIS1 silencing led to activation of the NOTCH signalling via induction of HIF1A, which in turn further supports EMT for sustaining tumor invasion and metastasis. Clinically, TIS1 was frequently downregulated in many human cancers including HCC and strongly associated with tumor recurrence, local invasion, and poor prognosis. In conclusion, a novel TIS1-HIF/NOTCH signaling forms a positive feedback loop sustainingly driving mesenchymal transition of cancer cells for invasion and metastasis. This TIS1-mediated tumor invasion and metastasis signaling may serve as therapeutic targets for prevention and treatment of HCC invasion and metastasis. Citation Format: Sen-Yung Hsieh. Functional genomics identifying a TIS1-HIF-NOTCH signaling orchestrating epithelial-mesenchymal transition for tumor invasion. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1447. doi:10.1158/1538-7445.AM2015-1447

Abstract 4108: NKX6.1 suppresses cancer invasion and epithelial-mesenchymal transition in cervical cancer

Abstract Cervical cancer is a common women malignancy worldwide. Recent reports emphasize inactivation of tumor suppressor genes are due to promoter hypermethylation in cervical cancer. Our previous study from methylation array has shown NK6 homeobox 1 (NKX6.1) is hypermethylated and downregulated in cervical cancer cell lines and clinical samples. Nkx6.1 contains a homeobox domain and functions as a transcription factor that regulates insulin-secreting β cell differentiation and neuronal fate determination. However, the biological function of NKX6.1 in cervical cancer remains elusive. Overexpression of NKX6.1 suppressed the transformation and invasive ability of HeLa and CaSki cells in vitro as well as decreased tumor formation and metastatic property in vivo. Conversely, knockdown of NKX6.1 strongly enhanced the transformation and invasiveness of SiHa cells. Epithelial-mesenchymal transition (EMT) has been shown to play a key role in the progression of uterine cervix carcinoma in situ (CIS) to invasive squamous cell carcinoma (SCC). NKX6.1 suppresses cancer invasiveness through coordinately increasing E-cadherin and decreasing Vimentin. Moreover, we demonstrated E-cadherin and vimentin were direct targets of NKX6.1 by luciferase reporter assay, electrophoretic mobility shift assay and chromatin immunoprecipitation quantitative polymerase chain reaction (Chip-qPCR) assay. Collectively, our data demonstrate NKX6.1 acts a tumor suppressor, and inhibits tumor invasion and metastasis by suppressing Epithelial-mesenchymal transition (EMT) in cervical cancer. These data imply that modulation of NKX6.1 expression may be a novel therapeutic option for treatment of cervical cancer. Citation Format: Hsin-Jung Li, Pei-Ning Yu, Yu-Lueng Shih, Ya-Wen Lin. NKX6.1 suppresses cancer invasion and epithelial-mesenchymal transition in cervical cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4108. doi:10.1158/1538-7445.AM2015-4108

Effects of miR-339-5p on invasion and prognosis of hepatocellular carcinoma

microRNAs (miRNAs) are short single-strand non-coding RNAs that regulate various cell processes at the post-transcriptional levels. Mounting evidences suggested that dysregulation of miRNA is associated with cancer progression and development. The aberrant expression of miR-339-5p has been found in some types of cancers, however, the association of miR-339-5p expression and hepatocellular carcinoma (HCC) is still unclear. Here, we measured the expression of miR-339-5p in HCC tissues and explored its clinicopathological and prognostic significance. The result showed that miR-339-5p expression level was significantly lower in HCC tissues compared with non-cancerous liver tissues. Moreover, patients with lower miR-339-5p expression level are associated with a poorer overall survival. Multivariate Cox regression analysis showed that the expression of miR-339-5p was an independent prognostic factor for HCC patients. In addition, we found that over-expression of miR-339-5p can inhibit HCC cell invasion. In conclusion, our results indicated that miR-339-5p may serve as a tumor suppressor and play important role in inhibiting tumor invasion. Our work implicates that miR-339-5p may serve as a prognostic marker and molecular therapeutic target in HCC.

Heat-shock factor 2 is a suppressor of prostate cancer invasion.

Heat-shock factors (HSFs) are key transcriptional regulators in cell survival. Although HSF1 has been identified as a driver of carcinogenesis, HSF2 has not been explored in malignancies. Here, we report that HSF2 suppresses tumor invasion of prostate cancer (PrCa). In three-dimensional organotypic cultures and the in vivo xenograft chorioallantoic membrane model HSF2 knockdown perturbs organoid differentiation and promotes invasiveness. Gene expression profiling together with functional studies demonstrated that the molecular mechanism underlying the effect on tumor progression originates from HSF2 steering the switch between acinar morphogenesis and invasion. This is achieved by the regulation of genes connected to, for example, GTPase activity, cell adhesion, extracellular matrix and actin cytoskeleton dynamics. Importantly, low HSF2 expression correlates with high Gleason score, metastasis and poor survival of PrCa patients, highlighting the clinical relevance of our findings. Finally, the study was expanded beyond PrCa, revealing that the expression of HSF2 is decreased in a wide range of cancer types. This study provides the first evidence for HSF2 acting as a suppressor of invasion in human malignancies.

MiR-206 is an independent prognostic factor and inhibits tumor invasion and migration in colorectal cancer.

microRNAs (miRNAs) are small non-coding RNAs that play important role in a variety of biological processes, and aberrant expression of miRNA is always associated with tumor progression and invasion. However, the role of miR-206 in colorectal cancer (CRC) is still unclear. In this study, the expression of miR-206 in CRC tissue was compared to paired normal adjacent tissue, and results indicate that miRNA-206 levels are significantly lower in CRC tissue compared to control tissue. Kaplan-Meier analysis showed that patients with low miR-206 expression had significantly poorer overall survival. In addition, we found that over-expression of miR-206 can inhibit CRC cell migration and invasion. In conclusion, our results suggest that miR-206 functions as a tumor suppressor by inhibiting CRC migration and invasion. These findings suggest that miR-206 may be useful as a new potential therapeutic target for CRC.

MicroRNA-708 is downregulated in hepatocellular carcinoma and suppresses tumor invasion and migration.

MicroRNA-708 (miR-708) has been identified as one of down-regulated miRNAs in hepatocellular carcinoma (HCC) tissues by Taqman miRNAs array and confirmed quantitatively by reverse transcription polymerase chain reaction (qRT-PCR). However, its involvement in HCC remains unclear. The aim of this study was to investigate the roles of miR-708 in carcinogenesis and cancer progression of HCC. QRT-PCR was performed to detect the expression of miR-708 in 100pairs of HCC and adjacent non cancerous tissues. Then, its associations with various clinicopathological features of HCC patients were statistically evaluated. After that, we also observed the effects of enforced miR-708 expression on migration and invasion of HCC cells in vitro. Our data confirmed that the expression level of miR-708 in HCC tissues was significantly lower than those in adjacent non-cancerous tissues (P=0.001). In addition, low miR-708 expression was found to be closely correlated with high Edmondson-Steiner grading (P=0.02) and advanced Tumor Node Metastasis (TNM) stage (P=0.01). Furthermore, the enforced expression of miR-708 could suppress the migration and invasion of HCC cell lines in vitro. Our findings support that miR-708, which is frequently down-regulated in HCC, may contribute to the aggressive progression of HCC and inhibit HCC cell mobility. Further studies on the identification of its target genes are required to be performed.

MUC2 Expression Is Correlated with Tumor Differentiation and Inhibits Tumor Invasion in Gastric Carcinomas: A Systematic Review and Meta-analysis.

Background:While MUC2 is expressed in intestinal metaplasia and malignant lesions, the clinicopathological significance of MUC2 expression is not fully elucidated in gastric carcinoma (GC).Methods:The present study investigated the correlation between MUC2 expression and clinicopathological parameters in 167 human GCs. In addition, to confirm the clinicopathological significance of MUC2 expression, we performed a systematic review and meta-analysis in 1,832 GCs.Results:MUC2 expression was found in 58 of 167 GCs (34.7%). MUC2-expressing GC showed lower primary tumor (T), regional lymph node (N), and tumor node metastasis (TNM) stages compared with GCs without MUC2 expression (p=.001, p=.001, and p=.011, respectively). However, MUC2 expression was not correlated with Lauren’s classification and tumor differentiation. In meta-analysis, MUC2 expression was significantly correlated with differentiation and lower tumor stage (odds ratio [OR], 1.303; 95% confidence interval [CI], 1.020 to 1.664; p = .034 and OR, 1.352; 95% CI, 1.055 to 1.734; p = .017, respectively) but not with Lauren’s classification, pN stage, or pTNM stage.Conclusions:MUC2 expression was correlated with a lower tumor depth and lower lymph node metastasis in our study; the meta-analysis showed a correlation of MUC2 expression with tumor differentiation and lower tumor depth.

Mo1493 EUS-Guided Intratumoral Injection of CHST15 Dsrna for Unresectable Pancreatic Cancer: an Investigator-Initiated Trial

Mo1493 EUS-Guided Intratumoral Injection of CHST15 Dsrna for Unresectable Pancreatic Cancer: an Investigator-Initiated Trial

Distinctive role of SIRT1 expression on tumor invasion and metastasis in breast cancer by molecular subtype.

The aim of this study was to evaluate silent mating type information regulation 2 homolog 1 (SIRT1) expression levels by subtype and evaluate its predictive power of axillary lymph node metastasis (LNM) and its association with clinical outcome. A total of 427 patients diagnosed with invasive ductal carcinoma were chosen, immunohistochemical staining for SIRT1 expression was performed on tissue microarrays, and in vitro experiments with each intrinsic subtype of human breast cancer cell line were carried out. Increased expression of SIRT1 in hormone receptor-positive breast cancer and HER2 breast cancer subtype significantly correlated with lower risks of LNM. On the contrary, in triple-negative breast cancer, increased SIRT1 expression was more frequently observed in LNM-positive subgroup than LNM-negative subgroup. Combination of statistically significant, independent parameters including SIRT1 revealed predictive performance for LNM with area under the curve of 0.602, 0.587, and 0.726 for hormone receptor-positive breast cancer, HER2 breast cancer, and triple-negative breast cancer subtype, respectively. Inhibition of SIRT1 expression with small interfering RNA suppressed tumor invasion in MDA-MB-231, specifically. This is the first study to examine SIRT1 expression in breast cancer by subtype, and we have observed the potentially different role of SIRT1 gene having tumor-suppressive or tumor-promoting influence depending on the subtype; thus, different associations between SIRT1 expression and prognosis by subtype should be considered in its target therapy.

Host protein C inhibitor inhibits tumor growth, but promotes tumor metastasis, which is closely correlated with hypercoagulability

IntroductionProtein C inhibitor (PCI), a member of the serine protease inhibitor family, is expressed in various human tissues, including liver and kidneys. In the plasma, PCI physiologically inhibits an anticoagulant serine protease, activated protein C (APC). PCI expressed by cancer cells suppresses tumor invasion by inhibiting urokinase-type plasminogen activator, and inhibits tumor growth and metastasis, which are independent of its protease-inhibitory activity. In the present study, we clarified the effects of host PCI on growth and metastasis of B16 melanoma (B16) cells by comparing between wild-type mice and mice transgenic for human PCI gene (hPCI-TG), which have a tissue distribution of PCI similar to that observed in humans. Materials and MethodsGrowth of intracutaneously-injected B16 cells was evaluated by measuring the tumor volume, and metastatic behavior of intravenously-injected B16 cells by counting the number of metastatic lung nodules. ResultsGrowth of intracutaneously injected B16 cells was significantly faster in wild-type mice than in hPCI-TG mice; however, hPCI-TG mice developed more metastatic nodules of B16 cells in the lungs. Immunohistochemical analysis using anti-mouse fibrinogen antibody revealed more fibrin deposition in the lung in hPCI-TG mice than in wild-type mice. Furthermore, the more invasive behavior observed in hPCI-TG mice was reduced by rabbit anti-human PCI IgG, APC, or soluble TM administration for 3 consecutive days including the day that B16 cells were injected. ConclusionsOur results suggest that like PCI expressed in tumor cells, host PCI also inhibits tumor growth, but host PCI promotes tumor metastasis via its procoagulant properties.

Study on the inhibitory effect of miR-199b on colorectal cancer metastasis

Objective To investigate the expression of miR-199b in colorectal cancer and the effect of miR-199b on metastasis of colorectal cancer. Methods The expression of miR-199b in colorectal cancer was assessed by quantitative reverse transcription polymerase chain reaction (qRT-PCR). The miR-199b-overexpressed human colon tumor-116 (HCT-116) stable cell lines was constructed by lentivirus assay. The effects of miR-199b on the migration and invasion of colorectal cancer were confirmed by Transwell assay. Bioinformatics, luciferase reporter assay, and enzyme linked immunosorbent assay (ELISA) were performed to verify the potential target genes of miR-199b. Results miR-199b was at lower level in cancerous tissues comparing to the corresponding noncancerous tissues. Up-regulation of miR-199b significantly blocked the migration and invasion of colorectal cancer cells. Co-transfection of miR-199b and VEGFA wild type (WT) 3'untranslated region (3'UTR) could inhibit the luciferase activity, while there was no significant difference when co-transfection with mutant (MT) 3'UTR. The protein level of vascular endothelial growth factor A (VEGFA) after overexpression of miR-199b was repressed, which was validated by ELISA. Conclusions miR-199b was a new colorectal cancer suppressor miRNA, which inhibited tumor migration and invasion by negatively regulating VEGF. Key words: MicroRNAs/BI/GE; Colorectal neoplasms/PA/ME/GE; Neoplasm invasiveness; Neoplasm metastasis

Thermo-chemotherapy Induced miR-218 upregulation inhibits the invasion of gastric cancer via targeting Gli2 and E-cadherin.

Thermo-chemotherapy has been proven to reduce the invasion capability of cancer cells. However, the molecular mechanism underlying this anti-invasion effect is still unclear. In this study, the role of thermo-chemotherapy in the inhibition of tumor invasion was studied. The results demonstrated that expression of miR-218 was downregulated in gastric cancer tissues, which had a positive correlation with tumor invasion and metastasis. In vitro thermo-chemotherapy increased miR-218 expression in SGC7901 cells and inhibited both proliferation and invasion of cancer cells. Gli2 was identified as a downstream target of miR-218, and its expression was negatively regulated by miR-218. The thermo-chemotherapy induced miR-218 upregulation was also accompanied by increasing of E-cadherin expression. In conclusion, the present study indicates that thermo-chemotherapy can effectively decrease the invasion capability of cancer cells and increase cell-cell adhesion. miR-218 and its downstream target Gli2, as well as E-cadherin, participate in the anti-invasion process.

Corrigendum] MicroRNA-320a inhibits tumor invasion by targeting neuropilin 1 and is associated with liver metastasis in colorectal cancer.

After carefully checking the original data of migration and invasion experiment, we find we had selected the wrong picture to show the effect of microRNA320a on the migration of LoVo cells. The corrected version of Fig. 6A shown below contains appropriate representative images. We apologize for the error and appreciate the opportunity to correct the scientific record. All authors agree with this correction. [the original article was published in the Oncology Reports 27: 685-694, 2012 DOI: 10.3892/or.2011.1561]

Hepatocellular Carcinoma Growth Is Inhibited by Euphorbia helioscopia L. Extract in Nude Mice Xenografts.

Euphorbia helioscopia L. is a traditional Chinese medicine; recently research found that its ethyl acetate extract (EAE) plays an important role on tumor cell proliferation, apoptosis, invasion, and metastasis in vitro. But the effect of EAE for tumor cells in vivo has not been reported. To explore the inhibitory effect of EAE and molecular mechanism on hepatocellular carcinoma (HCC) SMMC-7721 cells in vivo, we utilized the nude mouse xenograft model of HCC. Treated with EAE (50, 100, and 200 μg/mL), the volume of xenograft was measured during the entire process of EAE treatment. In EAE treatment group, the volume of xenograft was significantly reduced compared with the control group (P < 0.05) and the protein expressions of CyclinD1, bcl-2, and MMP-9 were reduced, while those of bax, caspase-3, and nm23-H1 were increased. A significant change trend with increasing EAE concentrations has presented, compared with controls. Moreover, the ultrastructural morphology of xenografts showed significant changes, including nuclear pyknosis and chromatin condensation, We found that EAE could effectively inhibit tumor growth, induce apoptosis, and inhibit tumor invasion and metastasis in vivo; it is suggested that EAE is a potential candidate for as a new anticancer agent.

LASS2/TMSG1 inhibits growth and invasion of breast cancer cell in vitro through regulation of vacuolar ATPase activity.

Homo sapiens longevity assurance homologue 2 of yeast LAG1 (LASS2)/tumor metastasis suppressor gene 1 (TMSG1) was a novel tumor metastasis-related gene identified using messenger RNA differential display from non-metastatic human prostate cancer cell variants. The mechanism of LASS2/TMSG1 inhibiting tumor invasion metastasis in breast cancer cells had not been well investigated. In the present study, a full length of 1.2kb LASS2/TMSG1 complementary DNA (cDNA) coding for a protein of 380 amino acids was cloned. PcDNA3 eukaryotic expression plasmids of LASS2/TMSG1 were constructed and transfected into human breast cancer cell line MCF-7 by lipofectin transfection method. And, the biological effects were observed comparing with control groups. As the result, LASS2/TMSG1 inhibited cell growth in vitro by increasing apoptosis and changing cell cycle distribution. Furthermore, the vacuolar ATPase (V-ATPase) activity and extracellular hydrogen ion concentration were significantly decreased and the activity of secreted matrix metalloproteinase-2 (MMP-2) was downregulated in MCF-7 cells overexpressing LASS2/TMSG1 compared with the controls. Therefore, LASS2/TMSG1 may inhibit growth and invasion of breast cancer cell in vitro through decreasing V-ATPase activity and extracellular hydrogen ion concentration and inactivating secreted MMP-2. The findings provided the evidence that the LASS2/TMSG1 gene had tumor growth and invasion suppressor function in human breast cancer cell and may provide a promising target for cancer metastasis diagnosis and therapy.

MiR-335 inhibits migration of breast cancer cells through targeting oncoprotein c-Met

Metastasis is the leading cause of death in patients with breast cancer and aberrantly expressed microRNAs (miRNAs) are highly associated with this process. A previous study has shown that miR-335 is downregulated in breast cancer and can suppress tumor invasion and metastasis. Emerging evidences indicate that c-Met is implicated in cell scattering, migration, and invasion. However, little is known about the relationship between miR-335 expression and c-Met alteration in breast cancer. In the present study, we found that miR-335 expression was downregulated and c-Met protein expression was upregulated in two human breast cell lines. MiR-335 was found to negatively regulate c-Met protein level by directly targeting its 3' untranslated region (UTR). Forced expression of miR-335 decreased c-Met expression at protein levels and consequently diminished hepatocyte growth factor (HGF)-induced phosphorylation of c-Met and subsequently inhibited HGF promotion of breast cancer cell migration in a c-Met-dependent manner. MiR-335 expression was increased after 5-aza-2'-deoxycytidine (5-AZA-CdR) treatment, and 5-AZA-CdR treatment resulted in the same phenotype as the effect of miR-335 overexpression. Taken together, these results demonstrate that miR-335 suppresses breast cancer cell migration by negatively regulating the HGF/c-Met pathway.