[Expression of Has-miR-93-5p in laryngeal squamous cell carcinoma and its clinical significance]

Objective:To investigate the expression of has-miR-93-5p on human laryngeal squamous cell carcinoma and the influence on malignant phenotype of Hep-2 cell.Method:The expression of has-miR-93-5p of paraffin samples in LSCC was determined by looped-primer Real-time PCR, and the relationship between the expression and the clinical pathological parameters was analysed. The has-miR-93-5p Inhibitor sequence was transfected into Hep-2 cells as the Inhibitor group. Using the MTS assay, Edu and colony formation assay to investigate the change of cell viability,proliferation and clone formation ability after transfection. Transwell invasion assay was used to detect the changes of cell migration and invasion ability. Flow cytometry was used to detect the changes of cell cycle and apoptosis.Result:The relative expression of has-miR-93-5p in LSCC was 11.148±1.141,which was higher than in normal tissues of adjacent to carcinoma1(985±4.547)（P <0.01）.The constituent ratio of has-miR-93-5p high expression in the group of low differentiation, T3+T4 and lymphatic metastasis was 69.8%、76.5%and 89.5%,which was higher than the group of high differentiation,T1+T2 and nonlymphatic metastasis respectively（P <0.05）, Inhibition the expression of has-miR-93-5p in vitro in Hep-2 cells could obviously inhibit the cell vitality, proliferation, clone, migration, and invasion ability, also could retardant the cells in G2/M phase, and promote its apoptosis.Conclusion: has-miR-93-5p might be an important molecule in pathogenesis of laryngeal squamous cell carcinoma. It could inhibit malignant phenotype of laryngeal squamous cancer cells when has-miR-93-5p expressionwas suppressed in vitro.

The Wnt Target Gene L1 in Colon Cancer Invasion and Metastasis

The Wnt-β-catenin signaling pathway is highly conserved during evolution and determines normal tissue homeostasis. Hyperactivation of Wnt-β-catenin signaling is a characteristic feature of colorectal cancer (CRC) development. β-catenin is a major transducer of the Wnt signal from the cytoplasm into the nucleus where it acts as a co-transcriptional activator of β-catenin-TCF target genes. β-catenin is also required for linking cadherin type cell-cell adhesion receptors to the cytoskeleton, and consequently Wnt-β-catenin signaling is an attractive system for investigating the role of adhesion-mediated signaling in both normal intestinal tissue homeostasis and CRC development. In this review, we summarize our studies on one Wnt-β-catenin target gene, L1, a member of the immunoglobulin-like cell adhesion transmembrane receptor family. We describe the mechanisms of L1-mediated signaling in CRC cells, its exclusive localization in invasive areas of CRC tissue, and its ability to increase cell motility and confer metastasis to the liver. We discuss the activation (by L1) of genes via an ezrin-NF-κB pathway and the induction of genes also found in the intestinal stem cell signature. By studying L1 (adhesion)-mediated signaling, we expect to learn about mechanisms regulating both normal intestinal homeostasis and CRC development.

Selective activator protein-1 inhibitor T-5224 prevents lymph node metastasis in an oral cancer model

Activator protein-1 (AP-1) is a transcriptional factor that regulates the expression of various genes associated with tumor invasion and migration. The purpose of our study was to assess the therapeutic effects of a novel selective AP-1 inhibitor, T-5224, in preventing lymph node metastasis in head and neck squamous cell carcinoma (HNSCC) in an orthotopic mouse model. We assessed the effect of T-5224 on HNSCC cell invasion, migration, proliferation, and MMP activity by carrying out an in vitro study using an invasion assay, scratch assay, WST-8 assay, and gelatin zymography. We also observed morphological changes in HNSCC cells by time-lapse microscopy. Furthermore, cervical lymph node metastasis was assessed using an orthotopic tumor model of human oral squamous cell carcinoma cells (HSC-3-M3) injected in the tongue of a BALB/c nude mouse. T-5224 (150 mg/kg) or vehicle was given orally every day for 4 weeks. Animals were killed and assessed for lymph node metastasis by H&E staining of resected lymph nodes. T-5224 significantly inhibited the invasion, migration, and MMP activity of HNSCC cells in a dose-dependent manner; there was no significant influence on cell proliferation. The antimetastatic effect of T-5224 was also confirmed in our animal study. The rate of cervical lymph node metastasis in the model was 40.0% in the T-5224-treated group (n = 30) versus 74.1% in the vehicle-treated group (n = 27; P < 0.05). In conclusion, T-5224 inhibited the invasion and migration of HNSCC cells in vitro, and prevented lymph node metastasis in head and neck cancer in an animal model.

Ubiquitin ligase UBE3C promotes melanoma progression by increasing epithelial-mesenchymal transition in melanoma cells

Melanoma is the most aggressive type of skin cancer, exhibiting extensive local invasion and early distant metastasis. Aberrant expression of ubiquitin-protein ligase E3C (UBE3C) plays a key role in tumor development and progression. In the present study, we analyzed UBE3C expression in samples of cancerous and normal skin tissue. Levels of UBE3C expression were much higher in primary and metastatic melanoma tissues than in normal skin, cutaneous squamous cell carcinoma or basal cell carcinoma. Melanoma cells overexpressing UBE3C frequently exhibited a mesenchymal phenotype, including reduced expression of the epithelial marker E-cadherin and expression of the mesenchymal marker vimentin. Knockdown of UBE3C expression in melanoma cells significantly suppressed melanoma growth and progression. Furthermore, silencing UBE3C led to increased E-cadherin expression and decreased vimentin and Snail1 expression. Thus UBE3C promotes melanoma progression, possibly by inducing epithelial-mesenchymal transition in melanoma cells. Inhibiting UBE3C activity may suppress melanoma invasion and metastasis and may represent a targeted therapeutic approach.

[The relationship between hypermethylation of Syk gene promoter and medulloblastoma cell invasion and metastasis]

OBJECTIVE

To investigate the effect of demethylation of Syk gene promoter by the methylation transferase inhibitor 5-aza-CdR on the invasion and metastasis of medulloblastoma cell line Daoy.

METHODS

Medulloblastoma cell line Daoy was treated with 5-aza-CdR in vitro. Methylation-specific PCR, real time-PCR and Western blot were used to detect Syk gene promoter methylation status, Syk mRNA and protein expression respectively. Transwell was employed to study the invasion and metastasis of medulloblastoma cell line Daoyby counting the cells that had invaded through Matrigel and migrated to the undersurface of the membrane before and after treatment of 5-aza-CdR.

RESULTS

In comparison to control group, Syk gene promoter of 5-aza-CdR-treated groups was demethylated and expression of Syk mRNA and protein was significantly up-regulated by 3.40±0.24 folds (P<0.01) and 3.23±0.19 folds (P<0.01) respectively. The invasiveness and metastasis of medulloblastoma cell line Daoy was decreased(P<0.05).

CONCLUSIONS

Hypermethylation of Syk gene promoter is responsible for the down-regulation of Syk gene expression in medulloblastoma cell line Daoy, which may be one of the mechanisms that enhanced cell invasion and metastasis. While 5-aza-CdR can reverse the hypermethylation of Syk gene promoter and restore Syk gene expression and thus suppresses invasiveness and metastasis of tumor cells.

miR-101 Inhibiting Cell Proliferation, Migration and Invasion in Hepatocellular Carcinoma through Downregulating Girdin

miR-101 is considered to play an important role in hepato-cellular carcinoma (HCC), but the underlying molecular mechanism remains to be elucidated. Here, we aimed to confirm whether Girdin is a target gene of miR-101 and determine the tumor suppressor of miR-101 through Girdin pathway. In our previous studies, we firstly found Girdin protein was overexpressed in HCC tissues, and it closely correlated to tumor size, T stage, TNM stage and Edmondson-Steiner stage of HCC patients. After specific small interfering RNA of Girdin was transfected into HepG2 and Huh7.5.1 cells, the proliferation and invasion ability of tumor cells were significantly inhibited. In this study, we further explored the detailed molecular mechanism of Girdin in HCC. Interestingly, we found that miR-101 significantly low-expressed in HCC tissues compared with that in matched normal tissues while Girdin had a relative higher expression, and miR-101 was inversely correlated with Girdin expression. In addition, after miR-101 transfection, the proliferation, migration and invasion abilities of HepG2 cells were weakened. Furthermore, we confirmed that Girdin is a direct target gene of miR-101. Finally we confirmed Talen-mediated Girdin knockout markedly suppressed cell proliferation, migration and invasion in HCC while down-regulation of miR-101 significantly restored the inhibitory effect. Our findings suggested that miR-101/Girdin axis could be a potential application of HCC treatment.

Intravital FRAP Imaging using an E-cadherin-GFP Mouse Reveals Disease- and Drug-Dependent Dynamic Regulation of Cell-Cell Junctions in Live Tissue

E-cadherin-mediated cell-cell junctions play a prominent role in maintaining the epithelial architecture. The disruption or deregulation of these adhesions in cancer can lead to the collapse of tumor epithelia that precedes invasion and subsequent metastasis. Here we generated an E-cadherin-GFP mouse that enables intravital photobleaching and quantification of E-cadherin mobility in live tissue without affecting normal biology. We demonstrate the broad applications of this mouse by examining E-cadherin regulation in multiple tissues, including mammary, brain, liver, and kidney tissue, while specifically monitoring E-cadherin mobility during disease progression in the pancreas. We assess E-cadherin stability in native pancreatic tissue upon genetic manipulation involving Kras and p53 or in response to anti-invasive drug treatment and gain insights into the dynamic remodeling of E-cadherin during in situ cancer progression. FRAP in the E-cadherin-GFP mouse, therefore, promises to be a valuable tool to fundamentally expand our understanding of E-cadherin-mediated events in native microenvironments.

MiR181c inhibits ovarian cancer metastasis and progression by targeting PRKCD expression

MicroRNAs (miRNAs) regulate many important cancer related gene expression in the posttranscriptional process. Dysregulated expression of miRNAs has been observed in numerous human cancers including ovarian cancer. In this study, we found that the expression of the miR-181c was significantly decreased in ovarian cancer tissue and in tissues with lymph node metastasis when compared with their control samples, respectively. Moreover, among pathological stages, the expression of miR-181c was significantly decreased in the tissues with IV stage compared with other stages. In vitro, miR-181c significantly inhibited the proliferation, metastasis of A2780 cell line, and induced G1 phase arrest. Through bioinformatics prediction, protein kinase C delta (PRKCD) was identified as a target gene of miR-181c. Western blot results showed that PRKCD was increased in ovarian cancer tissue, in tissues with lymph node metastasis and IV stage of ovarian cancer pathological samples. After knocking down PRKCD, the cell cycle of A2780 cells was also arrested in G1 phase. The proliferation and the metastasis of A2780 cells were reduced. The dual luciferase reporter experiments showed that miR-181c regulated the expression of PRKCD by combining with its 3'UTR. These results indicate that miR-181c inhibits ovarian cancer metastasis and progression by targeting PRKCD expression.

Functions of Shp2 in cancer

Diagnostics and therapies have shown evident advances. Tumour surgery, chemotherapy and radiotherapy are the main techniques in treat cancers. Targeted therapy and drug resistance are the main focus in cancer research, but many molecular intracellular mechanisms remain unknown. Src homology region 2-containing protein tyrosine phosphatase 2 (Shp2) is associated with breast cancer, leukaemia, lung cancer, liver cancer, gastric cancer, laryngeal cancer, oral cancer and other cancer types. Signalling pathways involving Shp2 have also been discovered. Shp2 is related to many diseases. Mutations in the ptpn11 gene cause Noonan syndrome, LEOPARD syndrome and childhood leukaemia. Shp2 is also involved in several cancer-related processes, including cancer cell invasion and metastasis, apoptosis, DNA damage, cell proliferation, cell cycle and drug resistance. Based on the structure and function of Shp2, scientists have investigated specific mechanisms involved in cancer. Shp2 may be a potential therapeutic target because this phosphatase is implicated in many aspects. Furthermore, Shp2 inhibitors have been used in experiments to develop treatment strategies. However, conflicting results related to Shp2 functions have been presented in the literature, and such results should be resolved in future studies.

The role of tumor-associated macrophages in breast carcinoma invasion and metastasis

The main purpose of this study was to investigate the infiltration of tumor-associated macrophages (TAMs) in normal and malignant breast tissue and the draining lymph nodes, and to explore its effect on breast cancer invasion and metastasis. The infiltration densities of TAMs was observed using immunohistochemical staining of CD68 in 100 cases of breast cancer specimens and its paired adjacent non-cancer breast tissues and draining lymph modes, and then to evaluate the relation of TAMs to various clinicopathological features including patients prognosis in breast carcinoma. We observed the infiltration densities of TAMs were significantly higher in breast carcinoma tissue than in adjacent normal tissue and significantly higher in much larger size and higher stage cases. Furthermore, infiltration densities of TAMs have negative correlation with the 5-year survival rates of breast cancer patients. But in matched lymph-nodes, the infiltration densities of TAMs were significantly lower in cancerous metastatic lymph-node samples than in non-metastatic one. Therefore, our data suggests that TAMs infiltration in primary tumor promote invasion and lymphatic metastasis of breast cancer and have negative correlation with patients prognosis in breast cancer, but in lymph-node TAMs may play another role and need further study in the future.

MicroRNA-365 inhibits growth, invasion and metastasis of malignant melanoma by targeting NRP1 expression

OBJECTIVE

The role of miR-365 in cancer cells seemed controversial in previous studies. We thereby in this article aimed to define the role of miR-365 in malignant melanoma (MM) pathogenesis.

METHODS

We detected miR-365 expression in malignant melanoma cell lines and then investigated the effects of miR-365 on the metastasis and malignancy of melanoma cells. The correlation between miR-365 level and NRP1 (neuropilin1) was further investigated in clinical malignant melanoma specimens.

RESULTS

MiR-365 was strongly down-regulated in malignant melanoma (MM) tissues and cell lines, and its expression levels were associated with lymph node metastasis and clinical stage, as well as overall survival and replase-free survival of MM. We also found that ectopic expression of miR-365 inhibited MM cell proliferation and MM metastasis in vitro and in vivo. We further identified a novel mechanism of miR-365 to suppress MM growth and metastasis. NRP1 was proved to be a direct target of miR-365, using luciferase assay and western blot. NRP1 over-expression in miR-365 expressing cells could rescue invasion and growth defects of miR-365. In addition, miR-365 expression inversely correlated with NRP1 protein levels in MM.

CONCLUSION

Our data suggest that miR-365 functions as a tumor suppressor in MM development and progression, and holds promise as a prognostic biomarker and potential therapeutic target for MM.

Attenuation of EGFL7 inhibits human laryngocarcinoma cells growth and invasion

AIM

To investigate its effect on the proliferation and invasion of laryngeal carcinoma and understand the potential underlying mechanisms to provide new targets for the diagnosis and treatment of recurrent laryngeal cancer metastasis.

METHODS

We constructed a lentiviral vector expressing EGFL7 specific shRNA, and introduced it in EGFL7 functions were attenuated by a lentiviral vector harboring shRNA targeting at EGFL7 in laryngeal carcinoma cell line Hep-2. Prolifereation and invasion assays were carried out in vitro. And in vivo tumor burden assay was done in nude mice.

RESULTS

The expression of EGFL7 was knocked-down by 80% in hep-2 cells transfected by the lentiviral EGFL7 shRNA vector and EGFL7 gene expression was detected by realtime PCR and Western blotting analysis respectively. The flow cytometric analysis showed that arrested the cell cycle in G1 phase, In tumor burden assay, to parental And vector control cells, the survival rates Of nude mice in EGFL7 shRNA group dropped down from the first day after implantation as indicated by MTT assay (P < 0.05). The formation and growth rate of xenograft tumor in mice transfected with siRNA against Bmi-1 slowed down significantly.

CONCLUSION

Attenuation of EGFL7 function significantly suppresses tumor growth and induces apoptosis, both in vitro and in vivo. EGFL7 may be play a key role in invasion and metastasis of Laryngeal squamous cell carcinoma (LSCC), thus would to be a new target for gene therapy in LSCC.

Targeting the hallmarks of cancer with therapy-induced endoplasmic reticulum (ER) stress

The endoplasmic reticulum (ER) is at the center of a number of vital cellular processes such as cell growth, death, and differentiation, crosstalk with immune or stromal cells, and maintenance of proteostasis or homeostasis, and ER functions have implications for various pathologies including cancer. Recently, a number of major hallmarks of cancer have been delineated that are expected to facilitate the development of anticancer therapies. However, therapeutic induction of ER stress as a strategy to broadly target multiple hallmarks of cancer has been seldom discussed despite the fact that several primary or secondary ER stress-inducing therapies have been found to exhibit positive clinical activity in cancer patients. In the present review we provide a brief historical overview of the major discoveries and milestones in the field of ER stress biology with important implications for anticancer therapy. Furthermore, we comprehensively discuss possible strategies enabling the targeting of multiple hallmarks of cancer with therapy-induced ER stress.

Metastatic cancer stem cells: from the concept to therapeutics

Metastatic cancer stem cells (MCSCs) refer to a subpopulation of cancer cells with both stem cell properties and invasion capabilities that contribute to cancer metastasis. MCSCs have capability of self-renewal, potentials of multiple differentiation and development and/or reconstruction of cancer tissues. As compared with stationary cancer stem cells, MCSCs are capable of invasion to normal tissues such as vasculatures, resistance to chemo- and/or radio-therapies, escape from immune surveillance, survival in circulation and formation of metastasis. MCSCs are derived from invasive cancer stem cells (iCSCs) due to the plasticity of cancer stem cells, which is one of the characteristics of cancer cell heterogeneity. Both stages of iCSCs and MSCSs are the potential therapeutic targets for cancer metastasis in the future strategies of personalized cancer therapy.

Monitoring the dynamics of Src activity in response to anti-invasive dasatinib treatment at a subcellular level using dual intravital imaging

Optimising response to tyrosine kinase inhibitors in cancer remains an extensive field of research. Intravital imaging is an emerging tool, which can be used in drug discovery to facilitate and fine-tune maximum drug response in live tumors. A greater understanding of intratumoural delivery and pharmacodynamics of a drug can be obtained by imaging drug target-specific fluorescence resonance energy transfer (FRET) biosensors in real time. Here, we outline our recent work using a Src-FRET biosensor as a readout of Src activity to gauge optimal tyrosine kinase inhibition in response to dasatinib treatment regimens in vivo. By simultaneously monitoring both the inhibition of Src using FRET imaging, and the modulation of the surrounding extracellular matrix using second harmonic generation (SHG) imaging, we were able to show enhanced drug penetrance and delivery to live pancreatic tumors. We discuss the implications of this dual intravital imaging approach in the context of altered tumor-stromal interactions, while summarising how this approach could be applied to assess other combination strategies or tyrosine kinase inhibitors in a preclinical setting.

Increased expression of macrophage migration inhibitory factor and DJ-1 contribute to cell invasion and metastasis of nasopharyngeal carcinoma

BACKGROUND AND AIM

Both macrophage migration inhibitory factor (MIF) and DJ-1 protein have been shown to relate with cell invasion and metastasis in tumors. However, the role of DJ-1 in invasion and metastasis of nasopharyngeal carcinoma (NPC) and its relation to MIF expression in NPC are not fully understood. The aim of present study is to determine whether or not MIF and DJ-1 are correlated with tumor invasion and influence a worse outcome in NPC, as well as its related mechanism.

METHODS

125 cases of NPC and 45 normal tissues of nasopharynx were collected. The expression of MIF and DJ-1 in tissue microarray was evaluated by immunohistochemical staining. Correlation between immunostainings and clinicopathological parameters, as well as the follow-up data of patients, was analyzed statistically. The association of MIF and DJ-1 with cell invasion and migration in NPC cell line were evaluated by small interfering RNA (siRNA) transfection, invasion assay and Western blotting.

RESULTS

MIF and DJ-1 staining was diffused and strong in tumor cells, whereas they were generally weaker and less common in normal lining epithelia of nasopharynx. High MIF expression in tumor cells (71.2%, 89/125 cases) were significantly associated with advanced clinical stage, lymph node metastasis, and worse prognosis of NPC patients. High expression of DJ-1 (75.2%, 94/125 cases) were closely correlated to lymph node metastasis and MIF high-expression. Only MIF high expression (P = 0.010) and lymph node metastasis (P = 0.004) emerged as strong independent prognostic factors for overall survival of NPC patients. In vitro, down-regulated expression of DJ-1 in NPC cell lines by siRNA was observed to reduce cell migration and invasion potential, however, exogenous MIF promoted cells invasion.

CONCLUSIONS

The data provided evidence that increased expression of MIF and DJ-1 induced cell invasion and metastasis of NPC, supporting the idea that MIF and DJ-1 may play important roles as regulators in the progression of NPC.

A mechanistic study on the metastasis inducing function of FUS-CHOP fusion protein in liposarcoma

The FUS-CHOP fusion protein has been found to be instrumental for specific oncogenic processes in liposarcoma, but its ability to induce metastasis and the underlying mechanisms by which this can be achieved remain unknown. To dissect its functional role in this context, we stably overexpressed this protein in SW872 liposarcoma and HT1080 fibrosarcoma cell lines, and were able to demonstrate that forced expression of FUS-CHOP significantly increases migration and invasion, as well as enhances lung and liver metastasis in the in vivo chicken chorioallantoic membrane (CAM) model, that is proliferation independent. Additionally, FUS-CHOP enhances the expression of matrix-metalloproteinases -2 and -9, and transactivates their promoters in vitro. Mutational analysis showed that C/EBP-β- (-769/-755), NF-κB (-525/-516) and CREB/AP-1 (-218/-207) sites were important for MMP-2 and NF-κB (-604/-598), AP-1 (-539/-532) and AP-1 (-81/-72) for MMP-9 transactivation. Moreover, a direct in vivo interaction of FUS-CHOP was observed in case of the MMP-2 promoter within region (-769/-207). siRNA data revealed that MMP-2 expression is essential in the FUS-CHOP induced metastatic phenotype. MMP-2-mRNA and protein expression correlated significantly with FUS-CHOP positivity in 46 resected patient liposarcoma tissues. We have for the first time provided substantial evidence for the FUS-CHOP oncoprotein as an inducer of metastasis that is due to the transcriptional induction of specific tumor-associated proteases. Insights gained from this study not only support a deeper understanding of the mechanistic properties of FUS-CHOP, but also open up new avenues for targeted therapy.

NF-κBP65 promotes invasion and metastasis of oesophageal squamous cell cancer by regulating matrix metalloproteinase-9 and epithelial-to-mesenchymal transition

NF-κB has been recognized as one of the factors responsible for the development of cancer; however, the mechanism by which high expression of NF-κB contributes to the progression of human oesophageal squamous cell cancer (ESCC) is not fully understood. In our investigations, NF-κBP65 was overexpressed in human ESCC tissues, especially in ESCC tissues with deep invasion and lymph node metastasis. Suppression of NF-κBP65 by siRNA decreased the invasion and proliferation ability of EC9706 cells in vitro. Furthermore, siRNA-mediated NF-κBP65 knock-down could lead to the downregulation of MMP-9, a metastasis-related gene. Reduced E-cadherin is a hallmark of invasive carcinomas that have acquired epithelial-mesenchymal transition (EMT) phenotypes and Vimentin is another molecule that is used widely as a marker of the EMT. We found upregulation of E-cadherin expression and downregulation of Vimentin was induced by NF-κBP65 siRNA, which suggests that NF-κBP65 siRNA could inhibit the invasion and proliferation ability of ECSS through attenuating the expression of MMP-9 and EMT. Thus, ESCC NF-κBP65 could be a useful target for cancer prevention and therapy.

SRC-3 has a role in cancer other than as a nuclear receptor coactivator

Steroid receptor coactivator-3 (SRC-3), also known as AIB1, is a member of the p160 steroid receptor coactivator family. Since SRC-3 was found to be amplified in breast cancer in 1997, the role of SRC-3 in cancer has been broadly investigated. SRC-3 initially was identified as a transcriptional coactivator for nuclear receptors such as the estrogen receptor (ER), involved in the proliferation of hormone-dependent cancers. However, increasing clinical evidence shows that dysregulation of SRC-3 expression in several human hormone-independent cancers is correlated with pathological factors and clinical prognosis. Recently, both in vivo and in vitro studies demonstrate that SRC-3 may influence a number of cancer cellular processes in several ways independent of nuclear receptor signaling. In addition, an SRC-3 transgenic mice model shows that SRC-3 induces tumors in several mouse tissues. These results indicate that the role of SRC-3 in cancer is not just as a nuclear receptor coactivator. The focus of this review is to examine possible SRC-3 roles in cancer, other than as a nuclear receptor coactivator.

Protein Signatures in Human MDA-MB-231 Breast Cancer Cells Indicating a More Invasive Phenotype Following Knockdown of Human Endometase/Matrilysin-2 by siRNA

Human matrix metalloproteinase-26 (MMP-26/endometase/matrilysin-2) is a putative biomarker for carcinomas of breast, prostate, and other cancers of epithelial origin. MMP-26 expression was silenced using small interfering RNA (siRNA) in the human breast cancer cell line MDA-MB-231. Immunological and proteomics approaches, including two-dimensional gel electrophoresis and matrix assisted laser desorption/ionization time-of-flight mass spectrometry, were employed to identify differential protein expression in MMP-26 knockdown cells. A comparison of the protein expression profiles of control and MMP-26 knockdown cells revealed nine differentially regulated proteins. Five of the proteins (heat shock protein 90, glucose-regulated protein 78 (GRP78), annexin V, tropomyosin, and peroxiredoxin II) were up-regulated, while alpha-tubulin, cystatin SA-III, breast cancer metastasis suppressor 1 (BRMS1) and beta-actin were down-regulated. This decrease of BRMS1 expression is concomitant with an increase of invasion through matrix-coated membranes. These results suggest an important role for MMP-26 in the regulation of proteins involved in invasive and metastatic breast cancers.

Enzastaurin inhibits invasion and metastasis in lung cancer by diverse molecules

BACKGROUND

Enzastaurin (Enz) is a serine/threonine kinase inhibitor blocking protein kinase C (PKC)beta/AKT pathway. However, an ability of this compound to inhibit cancer invasion and metastasis is not yet clearly elucidated.

METHODS

The ability of Enz to inhibit invasion and metastasis, and to target molecules was investigated in non-small cell lung cancer (NSCLC) by RT-PCR validated microarray, Matrigel, and in vivo chorionallantoic membrane (CAM) assays.

RESULTS

Enzastaurin significantly reduced migration, invasion, and in vivo metastasis to lungs and liver (CAM assay) of diverse NSCLC cell lines. Genes promoting cancer progression (u-PAR, VEGFC, and HIF1alpha) and tumour suppression (VHL, RASSF1, and FHIT) of NSCLC were significantly (P<0.05) down- or upregulated after Enz treatment in H460, A549, and H1299 cells, respectively. Luciferase/chromatin immunoprecipitation analysis showed that Enz transcriptionally controls urokinase-type plasminogen activator receptor (u-PAR) expression by promoter inhibition through Sp1, Sp3, and c-Jun(AP-1). Moreover, siRNA knockdown of u-PAR re-sensitised Enz-resistant cells and induced apoptosis, suggesting u-PAR as a marker of Enz resistance.

CONCLUSION

This study shows that Enz inhibits migration, invasion, and in vivo metastasis by targeting u-PAR, besides further targeting progression-related and tumour-suppressor genes in NSCLC. Together with u-PAR being a novel putative marker of Enz response, these data encourage molecularly tailored clinical studies on Enz in NSCLC therapy.

Expression of MTA1 promotes motility and invasiveness of PANC-1 pancreatic carcinoma cells

The human metastasis-associated protein 1 (MTA1) is a constituent of the nucleosome-remodelling and -deacetylation complex. Its expression has been correlated with the invasion and metastasis of epithelial neoplasms. To address the functional consequences of MTA1 expression in pancreatic carcinoma cells, we have established PANC-1 pancreatic carcinoma cells that stably express MTA1 as an enhanced green fluorescent fusion protein (EGFP-MTA1). Here, we demonstrate that heterologous expression of EGFP-MTA1 markedly enhanced the cellular motility and the invasive penetration of epithelial barriers by the cells. Expression of EGFP-MTA1 had no effect on substrate-independent growth, but reduced substrate-dependent cell proliferation. In addition, the organisation of the cytokeratin filament system and the localisation of the actin cytoskeleton-associated protein IQGAP1 were distinctly altered in EGFP-MTA1-expressing cells. These results indicate that enhanced expression of MTA1 promotes the acquisition of an invasive, metastatic phenotype, and thus enhances the malignancy of pancreatic adenocarcinoma cells by modulation of the cytoskeleton.

Membrane-type 1 matrix metalloproteinase cleaves CD44 and promotes cell migration

Migratory cells including invasive tumor cells frequently express CD44, a major receptor for hyaluronan and membrane-type 1 matrix metalloproteinase (MT1-MMP) that degrades extracellular matrix at the pericellular region. In this study, we demonstrate that MT1-MMP acts as a processing enzyme for CD44H, releasing it into the medium as a soluble 70-kD fragment. Furthermore, this processing event stimulates cell motility; however, expression of either CD44H or MT1-MMP alone did not stimulate cell motility. Coexpression of MT1-MMP and mutant CD44H lacking the MT1-MMP-processing site did not result in shedding and did not promote cell migration, suggesting that the processing of CD44H by MT1-MMP is critical in the migratory stimulation. Moreover, expression of the mutant CD44H inhibited the cell migration promoted by CD44H and MT1-MMP in a dominant-negative manner. The pancreatic tumor cell line, MIA PaCa-2, was found to shed the 70-kD CD44H fragment in a MT1-MMP-dependent manner. Expression of the mutant CD44H in the cells as well as MMP inhibitor treatment effectively inhibited the migration, suggesting that MIA PaCa-2 cells indeed use the CD44H and MT1-MMP as migratory devices. These findings revealed a novel interaction of the two molecules that have each been implicated in tumor cell migration and invasion.

Shedding of membrane type 1 matrix metalloproteinase in a human breast carcinoma cell line

Membrane type 1 matrix metalloproteinase (MT1-MMP) with a transmembrane domain is a new member of the MMP gene family and is expressed on the cell surfaces of many carcinoma cells to activate the zymogen of MMP-2 (gelatinase A). We have previously reported that MT1-MMP is released into culture media in a complex form with tissue inhibitor of metalloproteinases 2 (TIMP-2) from a human breast carcinoma cell line, MDA-MB-231, treated with concanavalin A (Con A). In the present study, we further studied the release mechanism of MT1-MMP. Immunoblot analysis indicated that the amounts of MT1-MMP in culture media increase with the time of exposure and the concentration of Con A, and those in cell lysates conversely decrease in a similar way. Time- and dose-dependent release of MT1-MMP into the media was confirmed by a sandwich enzyme immunoassay specific to MT1-MMP. The molecular weight of the immunoreactive MTI-MMP in the media was Mr 56,000, which was 4,000-Mr smaller than that in the cell lysates. Northern blot analysis demonstrated that the mRNA expression level of MT1-MMP is about 3-fold enhanced after a 24 h-exposure to Con A and this is maintained up to 72-h exposure. The release of MT1-MMP from the Con A-treated cells was inhibited by metalloproteinase inhibitors such as EDTA and o-phenanthroline, but not by MMP inhibitors including TIMP-1, TIMP-2 and BB94 or other proteinase inhibitors of serine, cysteine and aspartic proteinases. During the Con A treatment of the cells, cell viability decreased time- and dose-dependently and dead cells reacted positively in the TdT-mediated dUTP Nick-End Labeling (TUNEL) method. Con A-treated MDA cells showed apoptotic morphology when stained with Hoechst dye and hematoxylin and eosin. DNA ladder formation was detected by electrophoresis of the DNA from Con A-treated MDA cells. These results suggest that MT1-MMP release from Con A-treated cells is due to shedding mediated by metalloproteinase(s) other than MMPs, and is associated with apoptosis.

Enhancement of tumorigenicity and invasion capacity of rat mammary adenocarcinoma cells by epidermal growth factor and transforming growth factor-beta

We have studied the effects of growth factors and cytokines on the tumorigenicity and invasion capacity of tumor cells by using regressor and progressor tumor cell lines (ER-1 and ERpP, respectively) derived from an SHR rat mammary adenocarcinoma. ER-1 cells regress spontaneously whereas ERpP cells show invasive growth and high metastasis to lung and other organs in syngeneic SHR rats. When ER-1 cells were pretreated with either epidermal growth factor (EGF) or transforming growth factor-beta (TGF-beta) for 24 h in vitro, and intraperitoneally transplanted into SHR rats, they grew and killed the host, whereas ER-1 cells pretreated with tumor necrosis factor-alpha did not. Tumorigenicity and invasion capacity of ERpP cells were also enhanced by treatment with EGF and TGF-beta. The ER-1 cells pretreated with EGF, once grown in vivo, had acquired irreversible tumorigenicity and invasion capacity without requiring further EGF treatment, and the enhanced malignancy was irreversible. These findings suggest that growth factors play an important role in acquisition of malignancy of tumor cells.