Downregulation of metastasis suppressor 1(MTSS1) is associated with nodal metastasis and poor outcome in Chinese patients with gastric cancer

A potential new biomarker in HNSCC: metastasis suppressor protein 1 (MTSS1)

OBJECTIVE

Metastasis suppressor protein 1 (MTSS1) is a prognostic tumour marker in different malignant epithelial tumour entities and previously mainly the MTSS1 expression was analysed. This study evaluated the best analysis method as a prognosis and aggressiveness tumour marker in head and neck squamous cell carcinoma (HNSCC).

STUDY DESIGN

MTSS1 expression, MTSS1 intensity, interpretation MTSS1 score and MTSS1 edging score were analysed in formalin-fixed paraffin-embedded tissue slices of 60 patients with proven HNSCC and correlated with clinical and pathological outcome parameters.

RESULTS

A lack of MTSS1 expression showed tumour aggressiveness, but surprisingly, mainly MTSS1 intensity was correlated with a worse patient outcome. There was a significant correlation between higher MTSS1 intensity and an increased risk for lymph node metastasis (P = .027) and a significant increased risk for extracapsular growth (P = .016). Furthermore, disease-specific survival was worse in cases with higher MTSS1 intensity (P = .001).

CONCLUSION

MTSS1 intensity has a high scientific potential for further studies and could potentially be used as a prognostic marker in diagnostic and therapeutic decision-making.

Metastasis suppressor genes in clinical practice: are they druggable?

Since the identification of NM23 (now called NME1) as the first metastasis suppressor gene (MSG), a small number of other gene products and non-coding RNAs have been identified that suppress specific parameters of the metastatic cascade, yet which have little or no ability to regulate primary tumor initiation or maintenance. MSG can regulate various pathways or cell biological functions such as those controlling mitogen-activated protein kinase pathway mediators, cell-cell and cell-extracellular matrix protein adhesion, cytoskeletal architecture, G-protein-coupled receptors, apoptosis, and transcriptional complexes. One defining facet of this gene class is that their expression is typically downregulated, not mutated, in metastasis, such that any effective therapeutic intervention would involve their re-expression. This review will address the therapeutic targeting of MSG, once thought to be a daunting task only facilitated by ectopically re-expressing MSG in metastatic cells in vivo. Examples will be cited of attempts to identify actionable oncogenic pathways that might suppress the formation or progression of metastases through the re-expression of specific metastasis suppressors.

MTSS1 curtails lung adenocarcinoma immune evasion by promoting AIP4-mediated PD-L1 monoubiquitination and lysosomal degradation

Immune checkpoint blockade (ICB) therapy targeting PD-1/PD-L1 has shown durable clinical benefits in lung cancer. However, many patients respond poorly to ICB treatment, underscoring an incomplete understanding of PD-L1 regulation and therapy resistance. Here, we find that MTSS1 is downregulated in lung adenocarcinoma, leading to PD-L1 upregulation, impairment of CD8⁺ lymphocyte function, and enhanced tumor progression. MTSS1 downregulation correlates with improved ICB efficacy in patients. Mechanistically, MTSS1 interacts with the E3 ligase AIP4 for PD-L1 monoubiquitination at Lysine 263, leading to PD-L1 endocytic sorting and lysosomal degradation. In addition, EGFR-KRAS signaling in lung adenocarcinoma suppresses MTSS1 and upregulates PD-L1. More importantly, combining AIP4-targeting via the clinical antidepressant drug clomipramine and ICB treatment improves therapy response and effectively suppresses the growth of ICB-resistant tumors in immunocompetent mice and humanized mice. Overall, our study discovers an MTSS1-AIP4 axis for PD-L1 monoubiquitination and reveals a potential combinatory therapy with antidepressants and ICB.

Knockdown of lncRNA ZEB2NAT suppresses epithelial mesenchymal transition, metastasis and proliferation in breast cancer cells

Breast cancer is the second most common cause of cancer-related mortality in women. Breast cancer metastasis which usually is observed at the last stage is the major cause of breast cancer-related death. Long non-coding RNAs (lncRNAs) are member of the non-coding RNA family. It is known that lncRNAs have important functions in the genes regulation of different processes and pathways such as EMT (Epithelial mesenchymal transition), metastasis and apoptosis. Therefore, it is inevitable that lncRNAs have potential contribution for the understanding of cancer pathogenesis. lncRNA-ZEB2NAT is the natural antisense transcript of ZEB2. Herein, we investigated the effects of lncRNA-ZEB2NAT on process of EMT, metastasis and apoptosis in MCF7 and MDA-MB-231 breast cancer cells. The effect of ZEB2NAT on the expression of important genes in EMT, metastasis and apoptosis, and some protein levels was determined by qRT-PCR and western blot analysis, respectively. The effects of ZEB2NAT on cell proliferation, apoptosis, invasion and colony formation were evaluated using XTT, annexin V, invasion and colony assays, respectively. The ZEB2NAT knockdown caused anti-metastatic and apoptotic effects. The ZEB2NAT knockdown resulted in a decrease in ZEB2 and N-cadherin but an increase in E-cadherin protein levels. In addition, it was determined that ZEB2NAT knockdown significantly decreased cell proliferation and stimulated apoptosis in both cells. It was found that ZEB2NAT knockdown significantly decreased invasion and colony formation in both cells. ZEB2NAT knockdown showed anti-metastatic and apoptotic effect by affecting the important genes in both cells. These results have suggested that ZEB2NAT has an important role in EMT, metastasis and apoptosis in breast cancer and ZEB2NAT knockdown caused significant anti-cancer activities.

Metformin suppresses breast cancer growth via inhibition of cyclooxygenase-2

Pre-clinical and on-going trials have indicated the advantage of using metformin as an anticancer drug alone or in combination with other chemotherapeutics for the treatment of patients with breast cancer. However, the mechanisms by which metformin attenuates tumorigenesis remain to be further elucidated. The present study investigated the anticancer effects of metformin in breast cancer and identified potential molecular targets of metformin using western blotting and immunohistochemical analysis. Metformin significantly decreased tumor cell proliferation in vitro and suppressed tumor growth in vivo. Moreover, it induced the activation of AMP-induced protein kinase and suppression of phosphorylated-eukaryotic translation initiation factor 4E-binding protein 1 (p-4E-BP1), a downstream effector of the mTOR signaling pathway, and decreased cyclin D1 levels in in vitro and in vivo experimental models. Additionally, metformin inhibited cyclooxygenase (COX)-2 expression. Clinically, high expression levels of COX-2 and p-4E-BP1 in tissues of patients with breast cancer were significantly associated with enhanced lymphatic metastasis and distant metastasis. Thus, the current data suggested that metformin may have potential value as a synergistic therapy targeting both the COX-2 and mTOR signaling pathways.

Circ_002059 suppresses cell proliferation and migration of gastric cancer via miR-182/MTSS1 axis

Circular RNAs (circRNAs) play either oncogenic or tumor suppressive roles in gastric cancer (GC). A previous study demonstrated that circ_002059, a typical circRNA, was downregulated in GC tissues. However, the role and mechanism of circ_002059 in GC development are still unknown. In this study, the levels of circ_002059, miR-182, and metastasis suppressor-1 (MTSS1) were examined by real-time quantitative polymerase chain reaction and western blot analysis. Cell proliferation and migration were evaluated by MTT assay and Transwell migration assay, respectively. The interactions between miR-182 and circ_002059 or MTSS1 were analyzed by dual-luciferase reporter assay. A GC xenograft model was established to validate the role of circ_002059 in GC progression in vivo. Overexpression of circ_002059 significantly inhibited, whereas knockdown of circ_002059 notably facilitated, cell proliferation and migration in GC cells. MTSS1 was found to be a direct target of miR-182 and circ_002059 upregulated MTSS1 expression by competitively sponging miR-182. Transfection with miR-182 mimic and MTSS1 silencing abated the inhibitory effect of circ_002059 on GC progression. Circ_002059 inhibited GC cell xenograft tumor growth by regulating miR-182 and MTSS1 expression. Collectively, Circ_002059 inhibited GC cell proliferation and migration in vitro and xenograft tumor growth in mice, by regulating the miR-182/MTSS1 axis.

A reciprocal feedback of Myc and lncRNA MTSS1-AS contributes to extracellular acidity-promoted metastasis of pancreatic cancer

Rationale: Previous studies have reported on the role of extracellular acidity in the metastasis of numerous cancers. However, the involvement of long noncoding RNA (lncRNA) in the extracellular acidity-induced cancer metastasis of pancreatic cancer (PC) remains unclear.

Methods: Different expression levels of lncRNAs in PC cells under normal and acidic conditions were compared by RNA sequencing (RNA-seq). The effects of antisense lncRNA of metastasis suppressor 1 (MTSS1-AS) on acidic PC cells were assessed by gain- and loss-of-function experiments. Fluorescence in situ hybridization, RNA immunoprecipitation, RNA pull-down, Western blot, luciferase reporter, and Chromatin immunoprecipitation assays were employed to determine the regulatory mechanisms of MTSS1-AS in the acidity-induced metastasis of PC cells. The expression of MTSS1-AS and associated pathways were compared in PC samples and peritumoral normal tissues.

Results: RNA-seq demonstrated that MTSS1-AS was significantly downregulated in pancreatic cells cultured with the acidic medium. The overexpression of MTSS1-AS remarkably inhibited the acidity-promoted metastasis of PC cells by upregulating the expression of its sense gene metastasis suppressor 1 (MTSS1). Mechanistically, MTSS1-AS scaffolded the interaction between E3 ubiquitin-protein ligase STIP1 homology and U-box containing protein 1 (STUB1) and transcription regulator myeloid zinc finger 1 (MZF1), leading to ubiquitination-mediated degradation of MZF1. Further, MZF1 inhibited the expression of MTSS1 by binding to the MTSS1 promoter. Thus, the acidity-reduced MTSS1-AS facilitated the stability of MZF1 and its inhibitory effect on MTSS1 transcription, thereby promoting the metastasis of PC cells under acidic conditions. Moreover, MTSS1-AS was transcriptionally repressed by the binding of MYC proto-oncogene (Myc) with initiator (Inr) elements of the MTSS1-AS promoter. Meanwhile, MTSS1-AS mutually repressed the expression of Myc by impairing the MZF1-mediated transcription activation of Myc, thereby forming a negative feedback loop between MTSS1-AS and Myc in acidic PC cells. In accordance with the experimental results, MTSS1-AS and MTSS1 were downregulated in PC and correlated with poor overall survival.

Conclusions: The results implicated that a reciprocal feedback loop between Myc and MTSS1-AS contributed to the extracellular acidity-promoted metastasis of PC, and indicated that MTSS1-AS was a valuable biomarker and therapeutic target for PC.

Metastasis suppressor 1 acts as a tumor suppressor by inhibiting epithelial-to-mesenchymal transition in triple-negative breast cancer

OBJECTIVE

This study aimed to analyze the function of metastasis suppressor 1 (MTSS1) in triple negative breast cancer (TNBC).

METHODS

MTSS1 expression in 30 TNBC and paracancerous tissues was measured by quantitative reverse transcriptase polymerase chain reaction. The prognostic value of MTSS1 was assessed by Kaplan-Meier analysis followed by the log-rank test. MCF7 cells were transfected with si-MTSS1, while MDA-MB-231 cells were transfected with pcDNA3.1-MTSS1. Cell proliferation assay and transwell assay were performed to investigate the effects of MTSS1 on the biological behavior of breast cancer cells. Immunofluorescence and western blot were used to detect the influence of MTSS1 on epithelial-mesenchymal transition (EMT) markers.

RESULTS

MTSS1 expression was significantly lower in TNBC tissues compared with that in paracancerous tissues (0.012 vs. 0.370; P = 0.006). A lower MTSS1 expression level was also found in tumor tissues of patients with lymph node metastasis (P = 0.002) or tumor node metastasis stage (P = 0.010). Patients with low expression of MTSS1 (⩽ 0.009) had shorter disease-free survival (47.4 vs. 56.0 months; P = 0.012). The knockdown of MTSS1 in MCF7 cells inhibited cell proliferation, enhanced cell migration and invasion capacities, decreased the E-cadherin level, and increased the vimentin level, whereas overexpression of MTSS1 in MDA-MB-231 cells had the opposite effects (P < 0.05).

CONCLUSIONS

Our findings demonstrated that MTSS1 regulates proliferation, invasion, migration, and EMT in TNBC, and that decreased MTSS1 is associated with shorter disease-free survival.

MTSS1 suppresses mammary tumor-initiating cells by enhancing RBCK1-mediated p65 ubiquitination

Tumor-initiating cells (TICs) are considered the culprits of cancer development and progression. Dysregulation of metastasis suppressor protein 1 (MTSS1) has been widely observed in tumor metastasis, but its functional contribution and mechanism in cancer is poorly understood. Here we report a role of MTSS1 in suppressing TICs in breast cancer. Mtss1 knockout (KO) enhances the mammary epithelial TIC subpopulation in both luminal and basal-like breast cancer mouse models. MTSS1 also suppresses tumorsphere formation in breast cancer cells. Mechanistically, MTSS1 interacts with the E3 ligase RanBP2-type and C3HC4-type zinc finger containing 1 (RBCK1) to facilitate RBCK1-mediated p65 ubiquitination and degradation, thus suppressing the NF-κB signaling pathway and tumorigenesis. In addition, actin beta-like 2 (ACTBL2) competes with RBCK1 for MTSS1 binding, leading to p65 stabilization. Importantly, MTSS1 silencing promotes patient-derived organoid formation and xenograft growth. MTSS1 downregulation in clinical tumors is also linked to worse prognosis. Overall our data reveal a new paradigm of NF-κB regulation and may have important implications in therapeutics targeting TICs.

Circular RNA SFMBT2 Inhibits the Proliferation and Metastasis of Glioma Cells Through Mir-182-5p/Mtss1 Pathway

Glioma is a common type of tumor in human central nervous system, and it is characterized with high mobility and mortality. The prognosis of patients with advanced glioma remains poor. Thus, it is necessary to develop novel therapeutic approaches for the treatment of this disease. Circular RNAs are a group of noncoding RNAs which have been detected in eukaryotic cells. They are tissue-specific and characterized with a more stable structure compared with linear RNAs. Recently, studies have revealed that certain circular RNAs are involved in biological processes such as gene regulation; however, the functions of most circular RNAs remain unknown and require further investigation. Furthermore, circular RNAs can act as "sponges" of its target microRNA, consequently suppressing their activity. Additionally, impaired expression of circular RNAs is reported in different diseases including cancer. In our study, low expression of circular RNA Scm like with 4 Mbt domains 2 was detected in glioma samples. Furthermore, reduced circRNA Scm like with 4 Mbt domains 2 expression was observed in human glioma cell lines compared to normal astrocyte cells. Additionally, overexpression of circRNA Scm like with 4 Mbt domains 2 suppressed the growth and metastasis of glioma cells in vitro. Moreover, microRNA-182-5p could be a downstream molecule of circRNA Scm like with 4 Mbt domains 2. The influenced of microRNA-182-5p-induced proliferation, migration, and invasion of glioma cells could be abrogated by overexpressed circRNA Scm like with 4 Mbt domains 2. In addition, metastasis suppressor 1 was predicted as a novel target of microRNA-182-5p, and its expression was restored by circRNA Scm like with 4 Mbt domains 2. In summary, our findings provided novel insight into the roles of circRNA Scm like with 4 Mbt domains 2 in glioma. More importantly, circRNA Scm like with 4 Mbt domains 2/microRNA-182-5p/metastasis suppressor 1 axis could be a putative therapeutic target for the treatment of patients with glioma.

Long non‑coding RNA MEG3 suppresses the growth of glioma cells by regulating the miR‑96‑5p/MTSS1 signaling pathway

Glioma is one of the most common types of tumor of the central nervous system with high mobility and mortality. The prognosis of patients with high-grade glioma is poor. Therefore, it is urgent to develop the therapeutic strategies for the treatment of glioma. Long non-coding RNAs (lncRNAs) have been reported as potential inducers or suppressors of numerous types of tumors including glioma. Previous studies have revealed that lncRNA maternally expressed gene 3 (MEG3) is involved in the initiation and progression of cancer; however, the underlying mechanisms remain unclear. In the present study, MEG3 was downregulated in glioma tissue. In addition, downregulation of MEG3 was observed in human glioma cell lines compared with normal astrocyte cells. Furthermore, overexpressed MEG3 inhibited the proliferation, migration and invasion of glioma cells. Additionally, microRNA-96-5p (miR-96-5p) was a promising target of MEG3, and the promoting effects of miR-96-5p on cell growth and metastasis could be reversed by upregulated MEG3. Metastasis suppressor 1 (MTSS1) was predicted as the putative target of miR-96-5p, and its expression was restored by MEG3. In summary, the present data provided novel insight into the roles of MEG3 in glioma, and MEG3/miR-96-5p/MTSS1 signaling could be a promising therapeutic target for the treatment of patients with glioma.

MTSS1 inhibits metastatic potential and induces G2/M phase cell cycle arrest in gastric cancer

Background: Metastasis suppressor 1 (MTSS1), a potential metastasis suppressor gene associated with tumor progression, may play an important role in cancer development. Our previous study demonstrated that MTSS1 was downregulated significantly when gastric cancer (GC) progressed and metastasized, suggesting that MTSS1 may be involved in the physiopathologic mechanism of GC.

Purpose: The objective of this study was to evaluate the effect of MTSS1 expression on the biological behavior of gastric cancer cell both in vitro and in vivo.

Materials and methods: The gain-and-loss function of MTSS1 in GC cells were analyzed after transfection with pEGFP-N1-MTSS1 and ShRNA431. Proliferation and invasion abilities were measured by means of plate clone formation assay and transwell assay. To further explore the underlying mechanism of MTSS1-induced tumor restrain, cell cycle distribution was analyzed using flow cytometry.

Results: The results revealed that overexpression of MTSS1 significantly reduced proliferation, migration and invasion of GC cells in vivo and in vitro, while downregulation of MTSS1 had the opposite biological manifestations. Moreover, overexpression of MTSS1 induced accumulation of GC cells in G2/M phase, increased phosphorylated Cdc2 expression and decreased Cdc25C and cyclinB1 levels, suggesting MTSS1 could cause G2/M cell cycle arrest.

Conclusion: Our data provided insight into an important role for MTSS1 in suppressing tumor cell proliferation, invasion and migration, indicating that MTSS, as a functional tumor suppressor in GC, could be a potential therapeutic target to prevent GC metastasis.

Advances in Targeting the Epidermal Growth Factor Receptor Pathway by Synthetic Products and Its Regulation by Epigenetic Modulators As a Therapy for Glioblastoma

Glioma is the most common primary tumor of the nervous system, and approximately 50% of patients exhibit the most aggressive form of the cancer, glioblastoma. The biological function of epidermal growth factor receptor (EGFR) in tumorigenesis and progression has been established in various types of cancers, since it is overexpressed, mutated, or dysregulated. Its overexpression has been shown to be associated with enhanced metastatic potential in glioblastoma, with EGFR at the top of a downstream signaling cascade that controls basic functional properties of glioblastoma cells such as survival, cell proliferation, and migration. Thus, EGFR is considered as an important therapeutic target in glioblastoma. Many anti-EGFR therapies have been investigated both in vivo and in vitro, making their way to clinical studies. However, in clinical trials, the potential efficacy of anti-EGFR therapies is low, primarily because of chemoresistance. Currently, a range of epigenetic drugs including histone deacetylase (HDAC) inhibitors, DNA methylation and histone inhibitors, microRNA, and different types of EGFR inhibitor molecules are being actively investigated in glioblastoma patients as therapeutic strategies. Here, we describe recent knowledge on the signaling pathways mediated by EGFR/EGFR variant III (EGFRvIII) with regard to current therapeutic strategies to target EGFR/EGFRvIII amplified glioblastoma.

Computational analysis of the evolutionarily conserved Missing In Metastasis/Metastasis Suppressor 1 gene predicts novel interactions, regulatory regions and transcriptional control

Missing in Metastasis (MIM), or Metastasis Suppressor 1 (MTSS1), is a highly conserved protein, which links the plasma membrane to the actin cytoskeleton. MIM has been implicated in various cancers, however, its modes of action remain largely enigmatic. Here, we performed an extensive in silico characterisation of MIM to gain better understanding of its function. We detected previously unappreciated functional motifs including adaptor protein (AP) complex interaction site and a C-helix, pointing to a role in endocytosis and regulation of actin dynamics, respectively. We also identified new functional regions, characterised with phosphorylation sites or distinct hydrophilic properties. Strong negative selection during evolution, yielding high conservation of MIM, has been combined with positive selection at key sites. Interestingly, our analysis of intra-molecular co-evolution revealed potential regulatory hotspots that coincided with reduced potentially pathogenic polymorphisms. We explored databases for the mutations and expression levels of MIM in cancer. Experimentally, we focused on chronic lymphocytic leukaemia (CLL), where MIM showed high overall expression, however, downregulation on poor prognosis samples. Finally, we propose strong conservation of MTSS1 also on the transcriptional level and predict novel transcriptional regulators. Our data highlight important targets for future studies on the role of MIM in different tissues and cancers.

MicroRNA-146b-3p Promotes Cell Metastasis by Directly Targeting NF2 in Human Papillary Thyroid Cancer

Background: MiR-146b has been reported to be overexpressed in papillary thyroid cancer (PTC) tissues and associated with aggressive PTC. MiR-146b is regarded as a relevant diagnostic marker for this type of cancer. MiR-146b-5p has been confirmed to increase cell proliferation by repressing SMAD4. However, detailed functional analysis of another mature form of miR-146b, miR-146b-3p, has not been carried out. This study aimed to identify the differential expression of miR-146b-5p and miR-146b-3p in more aggressive PTC associated with lymph node metastasis, and further elucidate the contribution and mechanism of miR-146b-3p in the process of PTC metastasis. Methods: Expression of miR-146b-5p and miR-146b-3p was assessed in formalin-fixed paraffin-embedded tissue samples from PTC patients, and the relationship with lymph node metastasis was analyzed. A variety of PTC cells, including BHP10-3, BHP10-3SC_mice, and K1 cells, were cultured and treated with miR-146b-5p or miR-146b-3p mimics/inhibitors. The cell migration and invasion abilities were characterized by the real-time cell analyzer assay and Transwell™ assay. PTC xenograft models were used to examine the effect of miR-146b-3p on PTC metastatic ability in vivo. Direct downstream targets of miR-146b-3p were analyzed by luciferase reporter assay and Western blotting. The mechanism by which miR-146b-3p affects cell metastasis was further characterized by co-transfection with merlin, the protein product of the NF2 gene. Results: MiR-146b-5p and miR-146b-3p expression was significantly higher in thyroid cancer tissues and cell lines than in normal thyroid tissue and cells. Moreover, expression of miR-146b-5p and miR-146b-3p was further increased in thyroid metastatic nodes than in thyroid cancer. After overexpression of miR-146b-5p or miR-146b-3p in BHP10-3 or K1 cells, PTC migration and invasion were increased. Notably, miR-146b-3p increased cell migration and invasion more obviously than did miR-146b-5p. Overexpression of miR-146b-3p also significantly promoted PTC tumor metastasis in vivo. Luciferase reporter assay results revealed that NF2 is a downstream target of miR-146b-3p in PTC cells, as miR-146b-3p bound directly to the 3' untranslated region of NF2, thus reducing protein levels of NF2. Overexpression of merlin reversed the enhanced aggressive effects of miR-146b-3p. Conclusions: Overexpression of miR-146b-5p and miR-146b-3p is associated with PTC metastasis. MiR-146b-3p enhances cell invasion and metastasis more obviously than miR-146b-5p through the suppression of the NF2 gene. These findings suggest a potential diagnostic and therapeutic value of these miRNAs in PTC metastasis.

Metastasis suppressor protein 1 regulated by PTEN suppresses invasion, migration, and EMT of gastric carcinoma by inactivating PI3K/AKT signaling

Epithelial-mesenchymal transition (EMT) is a crucial event for cancer progression and metastasis. Metastasis suppressor protein 1 (MTSS1) is a metastasis suppressor in several cancers. In this study, we elucidated the potential physiological function of MTSS1 in the invasion and migration of gastric cancer (GC), and its distinct role in EMT and subsequently determined the potential molecular mechanism. We observed that MTSS1 expression was downregulated in GC tissues and several GC cell lines (SGC-7901, MGC-803, MKN-28, MKN-45, and BGC-823). Importantly, forced expression of MTSS1 drastically diminished the cell viability in both SGC-7901 and MKN-45 cells. Moreover, overexpression of MTSS1 attenuated the invasion ability of these two cell lines. In addition to the invasive capability, introduction of MTSS1 led to a loss of migratory potential. Furthermore, augmentation of MTSS1 exhibited the typical EMT phenotype switch, accompanied by enhanced the expression of vimentin and N-cadherin and reduced E-cadherin expression. Interestingly, MTSS1 also repressed transforming growth factor beta 1 (TGF-β1)-induced EMT. Our mechanistic investigations revealed that MTSS1 was positively regulated by the phosphatase and tensin homolog (PTEN), and it functioned as a tumor suppressor, possibly by inactivating the phosphoinositide 3-kinase (PI3K)/v-akt murine thymoma viral oncogene (AKT) pathway in GC cells. Collectively, our data provide insight into an important role for MTSS1 in suppressing tumor cell invasion, migration and EMT, which indicates that MTSS1 may act as a prospective prognostic biological marker and a promising therapeutic target for GC.

MiR-423-5p in brain metastasis: potential role in diagnostics and molecular biology

During the last several years, a growing number of studies have shown that microRNAs (miRNAs) participate in cancer metastasis. Brain metastasis (BM) is a frequent complication of lung adenocarcinoma (LAD), and the incidence of locally advanced LAD with BM can be as high as 30-50%. This study was performed to identify the miRNA expression patterns of LAD with BM and to determine the biological role that miRNAs play in tumorigenesis. To this end, we conducted microarray and quantitative PCR analyses to evaluate BM-related miRNAs independently validated from a total of 155 patients with LAD. A series of in vivo and in vitro assays were also conducted to verify the impact of miRNAs on BM. We found significantly increased expression of miR-423-5p, and BM was predicted in non-small cell lung cancer when compared to LAD without BM. We next examined the function of miR-423-5p and discovered that it significantly promoted colony formation, cell motility, migration, and invasion in vitro. We computationally and experimentally confirmed that metastasis suppressor 1 (MTSS1) was a direct miR-423-5p target. Through a combination of image, histological, and molecular analyses, we found that miR-423-5p overexpression significantly increased tumor burden, local invasion, and distant BM. The level of MTSS1 expression was inversely correlated with miR-423-5p upregulation in the LAD specimens and was associated with survival of patients with BM. MiR-423-5p promoted BM in LAD and inhibited MTSS1 expression. Together, these results show that MiR-423-5p has the potential to be a marker of BM and/or a therapeutic target in LAD.

ADAM-17 is a poor prognostic indicator for patients with hilar cholangiocarcinoma and is regulated by FoxM1

Background

A-disintegrin and metalloproteinases (ADAMs) are members of a family of multidomain transmembrane and secreted proteins. Specific ADAMs are upregulated in human cancers and correlated with tumor progression and poor outcome, but rarely studied in human hilar cholangiocarcinoma (HC). This study aimed to explore the expression profiles of ADAMs and their potential underlying mechanisms promoting cancer progression.

Methods

mRNA expression of ADAM-9, − 10, − 11, − 12, − 15, − 17, − 28, and − 33 was analyzed in human hilar cholangiocarcinoma (HC) samples. Immunohistochemical (IHC) analysis was used to detect the expression of ADAM-10, − 17, − 28, and FoxM1 in HC. The regulation of ADAM-17 by FoxM1 and their functional study was investigated in vivo and in vitro.

Results

ADAM-10, − 17, and − 28 were upregulated in tumors compared with matched non-cancerous tissues. IHC analysis revealed increased expression of ADAM-10, − 17, and − 28 in HC cells, and ADAM17 seems to be an independent prognostic factor. ADAM-17 is regulated by FoxM1. A decrease in the expression of ADAM-17 by silencing FoxM1 led to an inhibition of cell proliferation, tumor growth, and the production of tumor necrosis factor α. IHC analysis showed co-expression of FoxM1 and ADAM-17 in HC specimens.

Conclusions

The findings of the present study show an important role of the cross-talk among FoxM1, ADAM-17, and TNFa in HC development and progression.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4294-9) contains supplementary material, which is available to authorized users.

MicroRNA profiling in MDA-MB-231 human breast cancer cell exposed to the Phaleria macrocarpa (Boerl.) fruit ethyl acetate fraction (PMEAF) through IIlumina Hi-Seq technologies and various in silico bioinformatics tools

ETHNOPHARMACOLOGICAL RELEVANCE

Phaleria macrocarpa (Scheff) Boerl, is a famous traditional medicinal plant which exhibited cytotoxicity against various cancerous cells. Traditionally, P. macrocarpa has been used to control cancer, impotency, hemorrhoids, diabetes mellitus, allergies, liver and heart disease, kidney disorders, blood diseases, acne, stroke, migraine, and various skin diseases.

AIM OF THE STUDY

Recent studies have demonstrated a potent anticancer potential of P. macrocarpa, especially against HeLa cell. The objective of this study was to investigate the regulation of miRNAs on MDA-MB-231 treated with P. macrocarpa ethyl acetate fraction (PMEAF).

MATERIALS AND METHODS

The regulation of miRNAs on MDA-MB-231 cells treated with PMEAF was studied through IIlumina, Hi-Seq. 2000 platform of Next Generation Sequencing (NGS) and various in silico bioinformatics tools.

RESULTS

The PMEAF treatment against MDA-MB-231 cells identified 10 upregulated and 10 downregulated miRNAs. A set of 606 target genes of 10 upregulated miRNAs and 517 target genes of 10 downregulated miRNAs were predicted based on computational and validated databases by using miRGate DB Query. Meanwhile, results from DAVID Bioinformatics Resources 6.8 specified the functional annotation of the upregulated miRNAs involvement in cancer pathway by suppressing the oncogenes and downregulating miRNAs by expressing the tumour suppressor genes in the regulation of apoptosis pathway.

CONCLUSION

In conclusion, the results of this study proved that PMEAF is a promising anticancer agent with high cytotoxicity against MDA-MB-231 breast cancer cells and it induced apoptotic cell death mechanism through the regulation of miRNAs. PMEAF might be the best candidate for developing more potent anticancer drugs or chemo preventive supplements.

Reprogramming human A375 amelanotic melanoma cells by catalase overexpression: Upregulation of antioxidant genes correlates with regression of melanoma malignancy and with malignant progression when downregulated

Reactive oxygen species (ROS) are implicated in tumor transformation. The antioxidant system (AOS) protects cells from ROS damage. However, it is also hijacked by cancers cells to proliferate within the tumor. Thus, identifying proteins altered by redox imbalance in cancer cells is an attractive prognostic and therapeutic tool. Gene expression microarrays in A375 melanoma cells with different ROS levels after overexpressing catalase were performed. Dissimilar phenotypes by differential compensation to hydrogen peroxide scavenging were generated. The melanotic A375-A7 (A7) upregulated TYRP1, CNTN1 and UCHL1 promoting melanogenesis. The metastatic A375-G10 (G10) downregulated MTSS1 and TIAM1, proteins absent in metastasis. Moreover, differential coexpression of AOS genes (EPHX2, GSTM3, MGST1, MSRA, TXNRD3, MGST3 and GSR) was found in A7 and G10. Their increase in A7 improved its AOS ability and therefore, oxidative stress response, resembling less aggressive tumor cells. Meanwhile, their decrease in G10 revealed a disruption in the AOS and therefore, enhanced its metastatic capacity.

These gene signatures, not only bring new insights into the physiopathology of melanoma, but also could be relevant in clinical prognostic to classify between non aggressive and metastatic melanomas.

PTEN-Dependent Stabilization of MTSS1 Inhibits Metastatic Phenotype in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) presents at metastatic stage in over 50% of patients. With a survival rate of just 2.7% for patients presenting with distant disease, it is imperative to uncover novel mechanisms capable of suppressing metastasis in PDAC. Previously, we reported that the loss of metastasis suppressor protein 1 (MTSS1) in PDAC cells results in significant increase in cellular migration and invasion. Conversely, we also found that overexpressing MTSS1 in metastatic PDAC cell lines corresponds with not only decreased metastatic phenotype, but also greater overall survival. While it is known that MTSS1 is downregulated in late-stage PDAC, the mechanism behind that loss has not yet been elucidated. Here, we build off our previous findings to present a novel regulatory mechanism for the stabilization of MTSS1 via the tumor suppressor protein phosphatase and tensin homolog (PTEN). We show that PTEN loss in PDAC cells results in a decrease in MTSS1 expression and increased metastatic potential. Additionally, we demonstrate that PTEN forms a complex with MTSS1 in order to stabilize and protect it from proteasomal degradation. Finally, we show that the inflammatory tumor microenvironment, which makes up over 90% of PDAC tumor bulk, is capable of downregulating PTEN expression through secretion of miRNA-23b, potentially uncovering a novel extrinsic mechanism of MTSS1 regulation. Collectively, these data offer new insight into the role and regulation of MTSS1in suppressing tumor cell invasion and migration and help shed light as to what molecular mechanisms could be leading to early cell dissemination in PDAC.

Missing-in-metastasis B (MIM-B) combined with caveolin-1 promotes metastasis of hepatocellular carcinoma

BACKGROUND

Increasing amounts of evidence indicate that Missing in metastasis B (MIM-B) promotes cancer metastasis. Here, we sought to better understand the mechanism through which MIM-B promotes tumor metastasis in hepatocellular carcinoma (HCC).

METHODS

We performed confocal microscopy analysis to determine the distributions of MIM-B and caveolin-1 and conducted co-immunoprecipitation assays to detect the interactions between MIM-B and caveolin-1 in vitro. We performed transwell assays to analyze the invasive ability of HCC cells. Changes in the expression levels of key genes and some molecular makers were detected by immunohistochemistry and western blotting in HCC tissue samples.

RESULTS

We found that MIM-B co-localizes with caveolin-1 and demonstrated that MIM-B and caveolin-1 interact in vitro. Repressing MIM-B and caveolin-1 expression inhibited the epidermal growth factor receptor signaling pathway. We overexpressed MIM-B and caveolin-1 in Hep3B cells, which enhanced Hep3B cell invasiveness. Furthermore, MHCC97H cell invasiveness was significantly decreased in cells in which MIM-B and caveolin-1 expression was inhibited. Additionally, we found that MIM-B and caveolin-1 were expressed at higher levels in HCC tissues than in paired normal tissues. Moreover, HCC patients with MIM-B and caveolin-1 up-regulation experienced significantly worse outcomes than controls (P < 0.001), and HCC patients with high MIM-B and caveolin-1 expression levels often developed pulmonary metastasis (P < 0.001).

CONCLUSIONS

MIM-B combined with caveolin-1 promotes metastasis of HCC, and elevated MIM-B and caveolin-1 expression levels are associated with a poor prognosis in HCC patients; therefore, MIM-B and caveolin-1 may represent novel targets for the diagnosis and treatment of HCC.

Loss of MTSS1 results in increased metastatic potential in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) has a 5-year survival rate of 7%. This dismal prognosis is largely due to the inability to diagnose the disease before metastasis occurs. Tumor cell dissemination occurs early in PDAC. While it is known that inflammation facilitates this process, the underlying mechanisms responsible for this progression have not been fully characterized. Here, we functionally test the role of metastasis suppressor 1 (MTSS1) in PDAC. Despite evidence showing that MTSS1 could be important for regulating metastasis in many different cancers, its function in PDAC has not been studied. Here, we show that loss of MTSS1 leads to increased invasion and migration in PDAC cell lines. Moreover, PDAC cells treated with cancer-associated fibroblast-conditioned media also have increased metastatic potential, which is augmented by loss of MTSS1. Finally, overexpression of MTSS1 in PDAC cell lines leads to a loss of migratory potential in vitro and an increase in overall survival in vivo. Collectively, our data provide insight into an important role for MTSS1 in suppressing tumor cell invasion and migration driven by the tumor microenvironment and suggest that therapeutic strategies aimed at increasing MTSS1 levels may effectively slow the development of metastatic lesions, increasing survival of patients with PDAC.

MicroRNAs as regulators and mediators of forkhead box transcription factors function in human cancers

Evidence has shown that microRNAs are widely implicated as indispensable components of tumor suppressive and oncogenic pathways in human cancers. Thus, identification of microRNA targets and their relevant pathways will contribute to the development of microRNA-based therapeutics. The forkhead box transcription factors regulate numerous processes including cell cycle progression, metabolism, metastasis and angiogenesis, thereby facilitating tumor initiation and progression. A complex network of protein and non-coding RNAs mediates the expression and activity of forkhead box transcription factors. In this review, we summarize the current knowledge and concepts concerning the involvement of microRNAs and forkhead box transcription factors and describe the roles of microRNAs-forkhead box axis in various disease states including tumor initiation and progression. Additionally, we describe some of the technical challenges in the use of the microRNA-forkhead box signaling pathway in cancer treatment.

Next generation sequencing of progressive colorectal liver metastases after portal vein embolization

Portal vein embolization (PVE) can be required to stimulate liver regeneration before hepatectomy for colorectal liver metastasis (CRCLM), however PVE may also trigger CRCLM progression in patients initially exhibiting chemotherapy response. Using RNA-seq, we aimed to determine the molecular networks involved in metastatic progression in this context. A prospective study including all CRCLM patients undergoing PVE prior to hepatectomy was conducted. Paired biopsies of metastatic lesions were obtained prior to and after PVE and total RNA was isolated and used to prepare Illumina rRNA-depleted TruSeq stranded cDNA libraries for HiSeq 100 bp paired-end sequencing. Patients were classified with progression of disease (PD_PVE) or stable disease (SD_PVE) post-PVE using 3D-CT tumor volumetric analysis.

RESULTS

Twenty patients were included, 13 (65.0%) in the PD_PVE group (median 58.0% (18.6-234.3) increase in tumor volume) and 7 (35.0%) in the SD_PVE group exhibiting continuous chemotherapy response (median -14.3% (-40.8 to -2.8) decrease in tumor volume) (p < 0.0001). Our results showed that progressive CRCLM after PVE undergo gene expression changes that indicate activation of core cancer pathways (IL-17 (p = 5.94 × 10^-03), PI3K (p = 8.71 × 10^-03), IL6 and IGF-1 signaling pathways), consistent with changes driven by cytokines and growth factors. Differential expression analysis in a paired model of progression (EdgeR, DeSeq) identified significantly dysregulated genes in the PD_PVE group (FOS, FOSB, RAB20, IRS2).

CONCLUSION

Differentially expressed genes and pathways with known links to cancer and metastasis were identified post-PVE in patients with disease progression. Highlighting these molecular changes is a crucial first step towards development of targeted therapeutic strategies that may mitigate the effects of PVE on tumor growth.

Missing-in-metastasis protein downregulates CXCR4 by promoting ubiquitylation and interaction with small Rab GTPases

Surface expression of chemokine receptor CXCR4 is downregulated by missing-in-metastasis protein (MIM; also known as MTSS1), a member of the inverse BAR (I-BAR)-domain protein family that recognizes and generates membranes with negative curvature. Yet, the mechanism for the regulation is unknown. Here, we show that MIM forms a complex with CXCR4 by binding to E3 ubiquitin ligase AIP4 (also known as ITCH) in response to stromal cell-derived factor 1 (SDF-1; also known as CXCL12). Overexpression of MIM promoted CXCR4 ubiquitylation, inhibited cellular response to SDF-1, caused accumulation and aggregation of multivesicular bodies (MVBs) in the cytoplasm, and promoted CXCR4 sorting into MVBs in a manner depending on binding to AIP4. In response to SDF-1, MIM also bound transiently to the small GTPase Rab5 at 5 min and to Rab7 at 30 min. Binding to Rab7 requires an N-terminal coiled-coil motif, deletion of which abolished MIM-mediated MVB formation and CXCR4 internalization. Our results unveil a previously unknown property of MIM that establishes the linkage of protein ubiquitylation with Rab-guided trafficking of CXCR4 in endocytic vesicles.

Missing in metastasis B, regulated by DNMT1, functions as a putative cancer suppressor in human lung giant-cell carcinoma

Missing in metastasis B (MIM-B) has been widely reported to inhibit cancer cell invasion and proliferation in a variety of human cancers. However, the functions of MIM-B in lung cancers are still controversial. In addition, the mechanisms and regulation of MIM-B are poorly understood. In the present study, we found that the invasion level of 95C human lung giant-cell carcinoma cells was elevated when MIM-B was knocked down, while the invasion of 95D was suppressed when MIM-B was overexpressed, proving that MIM-B suppresses human lung giant-cell carcinoma cell invasion, which is similar to its function in most cancers. Furthermore, we reported that an increase in DNA methylation density in the promoter of MIM-B by DNA methyltransferase 1 (DNMT1) is correlated with the silencing of MIM-B expression and the high metastasis of 95D human lung giant-cell carcinoma cell line. Taken together, MIM-B, which is regulated by DNMT1 through DNA methylation, is a putative cancer suppressor in human lung giant-cell carcinoma.

MTSS1 is epigenetically regulated in glioma cells and inhibits glioma cell motility

Epigenetic silencing by DNA methylation in brain tumors has been reported for many genes, however, their function on pathogenesis needs to be evaluated. We investigated the MTSS1 gene, identified as hypermethylated by differential methylation hybridization (DMH). Fifty-nine glioma tissue samples and seven glioma cell lines were examined for hypermethylation of the MTSS1 promotor, MTSS1 expression levels and gene dosage. GBM cell lines were treated with demethylating agents and interrogated for functional consequences of MTSS1 expression after transient transfection. Hypermethylation was significantly associated with IDH1/2 mutation. Comparative SNP analysis indicates higher incidence of loss of heterozygosity of MTSS1 in anaplastic astrocytomas and secondary glioblastomas as well as hypermethylation of the remaining allele. Reversal of promoter hypermethylation results in an increased MTSS1 expression. Cell motility was significantly inhibited by MTSS1 overexpression without influencing cell growth or apoptosis. Immunofluorescence analysis of MTSS1 in human astrocytes indicates co-localization with actin filaments. MTSS1 is down-regulated by DNA methylation in glioblastoma cell lines and is part of the G-CIMP phenotype in primary glioma tissues. Our data on normal astrocytes suggest a function of MTSS1 at focal contact structures with an impact on migratory capacity but no influence on apoptosis or cellular proliferation.

Overexpression of maelstrom promotes bladder urothelial carcinoma cell aggressiveness by epigenetically downregulating MTSS1 through DNMT3B

We have recently identified and characterized a novel oncogene, maelstrom (MAEL) from 1q24, in the pathogenesis of hepatocellular carcinoma. In this study, MAEL was investigated for its oncogenic role in urothelial carcinoma of the bladder (UCB) tumorigenesis/aggressiveness and underlying molecular mechanisms. Here, we report that overexpression of MAEL in UCB is important in the acquisition of an aggressive and/or poor prognostic phenotype. In UCB cell lines, knockdown of MAEL by short hairpin RNA is sufficient to inhibit cell growth, invasiveness/metastasis and suppressed epithelial-mesenchymal transition (EMT), whereas ectopic overexpression of MAEL promoted cell growth, invasive and/or metastatic capacity and enhanced EMT both in vitro and in vivo. We further demonstrate that MAEL could induce UCB cell EMT by downregulating a critical downstream target, the metastasis suppressor 1 (MTSS1) gene, ultimately leading to an increased invasiveness of cancer cells. Notably, overexpression of MAEL in UCB cells substantially enhanced the enrichment of DNA methyltrans-ferase (DNMT)3B and histone deacetylase (HDAC)1/2 on the promoter of the MTSS1, and thereby epigenetically suppressing the MTSS1 transcription. Downregulation of MTSS1 by MAEL in UCB cells is partially dependent on DNMT3B. Furthermore, we identify that beside the gene amplification of MAEL, miR-186 is a key negative regulator of MAEL and downregulation of miR-186 is another important mechanism for MAEL overexpression in UCBs. These data suggest that overexpression of MAEL, caused by gene amplification and/or decreased miR-186, has a critical oncogenic role in UCB pathogenesis by downregulation of MTSS1, and MAEL could be used as a novel prognostic marker and/or effective therapeutic target for human UCB.

Quantitative detection of TUSC3 promoter methylation -a potential biomarker for prognosis in lung cancer

Aberrant promoter methylation of tumor relevant genes frequently occurs in early steps of carcinogenesis and during tumor progression. Epigenetic alterations could be used as potential biomarkers for early detection and for prediction of prognosis and therapy response in lung cancer. The present study quantitatively analyzed the methylation status of known and potential gatekeeper and tumor suppressor genes [O-6-methylguanine-DNA methyltransferase (MGMT), Ras association domain family member 1A (RASSF1A), Ras protein activator like 1 (RASAL1), programmed cell death 4 (PDCD4), metastasis suppressor 1 (MTSS1) and tumor suppressor candidate 3 (TUSC3)] in 42 lung cancers and in corresponding non-malignant bronchus and lung tissue using bisulfite-conversion independent methylation-quantification of endonuclease-resistant DNA (MethyQESD). Methylation status was associated with clinical and pathological parameters. No methylation was found in the promoter regions of PDCD4 and MTSS1 of either compartment. MGMT, RASSF1A and RASAL1 showed sporadic (up to 26.2%) promoter methylation. The promoter of TUSC3, however, was frequently methylated in the tumor (59.5%), benign bronchus (67.9%) and alveolar lung (31.0%) tissues from each tumor patient. The methylation status of TUSC3 was significantly associated with smaller tumor size (P=0.008) and a longer overall survival (P=0.013). Pooled blood DNA of healthy individuals did not show any methylation of either gene. Therefore, methylation of TUSC3 shows prognostic and pathobiological relevance in lung cancer. Furthermore, quantitative detection of TUSC3 promoter methylation appears to be a promising tool for early detection and prediction of prognosis in lung cancer. However, additional studies are required to confirm this finding.

Effect of metastasis suppressor 1 on H1299 cells and its clinical significance in non-small cell lung cancer

The present study aimed to investigate the effect of metastasis suppressor 1 (MTSS1) on the proliferation, migration and invasion of human H1299 non-small cell lung cancer cells and its clinical significance in non‑small cell lung cancer. The target gene MTSS1-overexpressing lentivirus (LV-MTSS1) was transfected into H1299 cells and expression of MTSS1 was detected at the mRNA and protein levels. Cell Counting Kit-8, wound healing and Transwell assays revealed that the migration and invasion activities were significantly suppressed by MTSS1, but that it had no effect on cell proliferation. In addition, MTSS1 expression in tissue microarrays including samples from 223 cases of non-small cell lung cancer was tested by immunohistochemistry to explore the correlation between MTSS1 and clinicopathological characteristics and prognosis. MTSS1 suppressed H1299 cell migration and invasion, and its expression level can be used as a new independent factor for determining the prognosis of non-small cell lung cancer.

β-ionone modulates the expression of miRNAs and genes involved in the metastatic phenotype of microdissected persistent preneoplastic lesions in rats submitted to hepatocarcinogenesis

MicroRNAs (miRNAs) are post-transcriptional gene expression regulators which expression is frequently altered in hepatocellular carcinoma (HCC). β-ionone (βI) is noted for its ability to inhibit persistent preneoplastic lesions (pPNLs) in liver rats. We evaluated the expression of miRNAs involved in carcinogenesis and possible targets modulated by βI, in pPNLs and surrounding of microdissected tissues. Rats subjected to resistant hepatocyte model were treated during promotion stage with βI (16 mg/100 g body weight) or corn oil (CO; 0.25 mL/100 g body weight; controls). Five animals receive no treatment (NT). In CO group, 38 and 29 miRNAs showed reduced expression relative to NT (P < 0.05) in pPNLs and surrounding, respectively. No miRNAs showed increased expression in surrounding of the CO compared to NT group; however, 30 miRNAs showed increased expression (P ≤ 0.05) in pPNLs of the CO group. There was no difference between βI and CO groups (P > 0.05) in the expression of miRNAs in surrounding. In pPNLs βI increased expression of miR-122 and miR-34a (P ≤ 0.05) and reduced of Igf2 (P ≤ 0.05), target of the latter, compared to CO. Additionally, βI decreased the expression of miR-181c and its target Gdf2 (P ≤ 0.05). βI reduced the expression of miR-181b and miR-708 (P ≤ 0.05) and increased the expression of their respective target mRNAs Timp3 and Mtss1 (P ≤ 0.05), relative to CO group. Modulation of miRNAs target genes by βI was confirmed in vitro. βI is a promising chemopreventive agent in the initial stages of hepatocarcinogenesis, as it modulates the expression of the miRNAs and target genes that can alter the metastatic phenotype of HCC. © 2016 Wiley Periodicals, Inc.

Expression and Significances of MTSS1 in Pancreatic Cancer

Thus far, expression of metastasis suppressor 1 (MTSS1), its clinicopathologic and prognostic significances in pancreatic cancer (PC) remain unknown. Expression of MTSS1 was detected by Western blotting in PC cell lines, and by tissue microarray-based immunohistochemical staining in paired tumor and non-tumor samples from 242 patients with PC. Furthermore, the correlations between MTSS1 expression and clinicopathologic variables as well as overall survival were evaluated. In PC cell lines, MTSS1 was differentially expressed. In addition, MTSS1 expression was significantly lower in tumor than in non-tumor tissues (P < 0.001 in both McNemar and Mann-Whitney U tests). High tumoral expression of MTSS1 was closely associated with absence of lymph node metastasis (P = 0.023). Univariate analysis found that high MTSS1 expression in tumor tissues was a strong predictor of favorable overall survival in the whole cohort (P < 0.001). Besides, its impacts on prognosis were also observed in nine out of fourteen subgroups. Finally, MTSS1 expression was identified as an independent prognostic marker in the whole cohort (P = 0.031) as well as in six subgroups (P < 0.05), as shown by multivariate Cox regression test. Down-regulation of MTSS1 expression is evident in PC, and is associated with lymph node metastasis and poor prognosis.

Chromophobe renal cell carcinoma with and without sarcomatoid change: a clinicopathological, comparative genomic hybridization, and whole-exome sequencing study

Chromophobe renal cell carcinomas (CRCC) with and without sarcomatoid change have different outcomes; however, fewstudies have compared their genetic profiles. Therefore, we identified the genomic alterationsin CRCC common type (CRCC C) (n=8) and CRCC with sarcomatoid change (CRCC S) (n=4) using comparative genomic hybridization (CGH) and whole-exome sequencing. The CGH profiles showed that the CRCC C group had more chromosomal losses (72 vs. 18) but fewer chromosomal gains (23 vs. 57) than the CRCC S group. Losses of chromosomes 1p, 8p21-23, 10p16-20, 10p12-ter, 13p20-30, and 17p13 and gains of chromosomes 1q11, 1q21-23, 1p13-15, 2p23-24, and 3p21-ter differed between the groups. Whole-exome sequencing showed that the mutational status of 270 genes differed between CRCC (n=12) and normal renal tissues (n=18). In the functional enrichment analysis, the missense-mutated genes were classified into 6 biological processes (38 functions) and 5 pathways. The biological processes included cell adhesion, cell motility, ATP metabolism, sensory perception, carbohydrate and lipid metabolism and transport. The pathways included ATP-binding cassette transporter, extracellular matrix-receptor interaction, olfactory transduction, chondroitin sulfate biosynthesis, and hypertrophic cardiomyopathy. Whole-exome sequencing analysis revealed that the missense mutation statuses of 49 genes differed between the CRCC C and CRCC S groups. Furthermore, genetic alterations in metastasis suppressor 1, serine peptidase inhibitor Kazal type 8, transient receptor potential cation channel super family M member 6, Rh family B glycoprotein, and mannose receptor C type 1 were located in different chromosomal regions. These alterations may provide clues regarding CRCC tumorigenesis and provide a basis for future targeted therapies.

Reciprocal expression of p-AMPKa and p-S6 is strongly associated with the prognosis of gastric cancer

Activation of AMP-activated protein kinase (AMPK) suppressed mammalian target of rapamycin (mTOR) pathway, resulting in impaired cancer cell proliferation. Two cohorts (50 and 1072 cases) of patients with resected gastric adenocarcinoma were enrolled in the study. Immunohistochemical staining for p-AMPKa, p-ACC, p-mTOR, p-S6, and p-4EBP1 was performed on the 50-patient cohort. Tissue microarray blocks containing samples from 1072 patients of Chinese ethnicity were used for the immunohistochemical detection of p-AMPKa and p-S6 levels. p-AMPK and p-ACC were frequently inactivated in both cohorts of gastric cancer samples, while p-mTOR, p-S6, and p-4EBP1 were frequently activated in the small cohort of gastric cancer. However, only levels of p-AMPKa and p-S6 were associated with the overall survival of gastric cancer patients. In the larger 1072-patient cohort, downregulation of p-AMPKa and upregulation of p-S6 were associated with tumor progression and were independent predictors of survival after resection of primary gastric cancer. Therefore, reciprocal expression of p-AMPKa and p-S6 may be promising prognostic biomarkers in patients with gastric cancer.

MTSS1 is an independent prognostic biomarker for survival in intrahepatic cholangiocarcinoma patients

MTSS1 is a possible metastasis suppressor which has been proved to play a key role in metastasis of various tumors, yet its role in intrahepatic cholangiocarcinoma (ICC) remains unclear. In present study, we reported detection of MTSS1 expression in ICC and explored its clinical significances. Tissue microarrays containing 93 cases with ICC were constructed and immunohistochemistry was performed to detect MTSS1 expression on these arrays. PcDNA3.1-MTSS1 was transfected into QBC939 cell lines and cell function was measured by transwell assay. Data showed that MTSS1 expression was barely detectable in 56 cases (60.0%) of the 93 primary tumors and that lacking MTSS1 expression was significantly associated with tumor size, nodal metastases and advanced disease stage. In addition, survival analysis demonstrated that lacking MTSS1 expression also correlated significantly with tumor recurrence and poor outcome of patients with ICC. Meanwhile, enhanced expression of MTSS1 leaded to inhibition of the migration of QBC939 cell lines in vitro. These findings together support that MTSS1 may serve as a useful biomarker in predicting tumor recurrence and prognosis of ICC.

Identification of the Adapter Molecule MTSS1 as a Potential Oncogene-Specific Tumor Suppressor in Acute Myeloid Leukemia

The adapter protein metastasis suppressor 1 (MTSS1) is implicated as a tumor suppressor or tumor promoter, depending on the type of solid cancer. Here, we identified Mtss1 expression to be increased in AML subsets with favorable outcome, while suppressed in high risk AML patients. High expression of MTSS1 predicted better clinical outcome of patients with normal-karyotype AML. Mechanistically, MTSS1 expression was negatively regulated by FLT3-ITD signaling but enhanced by the AML1-ETO fusion protein. DNMT3B, a negative regulator of MTSS1, showed strong binding to the MTSS1 promoter in PML-RARA positive but not AML1-ETO positive cells, suggesting that AML1-ETO leads to derepression of MTSS1. Pharmacological treatment of AML cell lines carrying the FLT3-ITD mutation with the specific FLT3 inhibitor PKC-412 caused upregulation of MTSS1. Moreover, treatment of acute promyelocytic cells (APL) with all-trans retinoic acid (ATRA) increased MTSS1 mRNA levels. Taken together, our findings suggest that MTSS1 might have a context-dependent function and could act as a tumor suppressor, which is pharmacologically targetable in AML patients.

Whole genome expression profiling of blood cells in ovarian cancer patients -prognostic impact of the CYP1B1, MTSS1, NCALD, and NOP14

Ovarian cancer patients with different tumor stages and cell differentiation might be distinguished from each other by gene expression profiles in whole blood cell mRNA by the Affymetrix Human Gene 1.0 ST Array. We also examined if there is any association with other clinical variables, response to therapy, and residual tumor burden after surgery. Patients were divided into two groups, one with poor prognosis, advanced stage and poorly differentiated tumors (n = 22), and one group with good prognosis, early stage and well- to medium differentiated tumors (n = 11). Six genes were found to be differentially expressed: the PDIA3, LYAR, NOP14, NCALD and MTSS1 genes were down-regulated and the CYP1B1 gene expression was up-regulated in the poor prognosis group, all with p value <0.05, adjusted for mass comparison. In survival analyses, CYP1B1, MTSS1, NCALD and NOP14 remained significantly different (p<0.05). Patient groups did not differ in any transcript related to acute phase or immune responses. This minimal gene expression signature of prognostic ovarian cancer-related genes opens up an avenue for more practicable monitoring of ovarian cancer patients by simple peripheral blood tests, which may evolve into a tool to guide selection of curative and postoperative supportive therapies.

EGF induces microRNAs that target suppressors of cell migration: miR-15b targets MTSS1 in breast cancer

Growth factors promote tumor growth and metastasis. We found that epidermal growth factor (EGF) induced a set of 22 microRNAs (miRNAs) before promoting the migration of mammary cells. These miRNAs were more abundant in human breast tumors relative to the surrounding tissue, and their abundance varied among breast cancer subtypes. One of these miRNAs, miR-15b, targeted the 3' untranslated region of MTSS1 (metastasis suppressor protein 1). Although xenografts in which MTSS1 was knocked down grew more slowly in mice initially, longer-term growth was unaffected. Knocking down MTSS1 increased migration and Matrigel invasion of nontransformed mammary epithelial cells. Overexpressing MTSS1 in an invasive cell line decreased cell migration and invasiveness, decreased the formation of invadopodia and actin stress fibers, and increased the formation of cellular junctions. In tissues from breast cancer patients with the aggressive basal subtype, an inverse correlation occurred with the high expression of miRNA-15b and the low expression of MTSS1. Furthermore, low abundance of MTSS1 correlated with poor patient prognosis. Thus, growth factor-inducible miRNAs mediate mechanisms underlying the progression of cancer.

Silencing profilin-1 inhibits gastric cancer progression via integrin β1/focal adhesion kinase pathway modulation

AIM: To investigate the role of profilin-1 (PFN1) in gastric cancer and the underlying mechanisms.

METHODS: Immunohistochemical analysis, quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were performed to detect PFN1 expression in clinical gastric carcinoma and adjacent tissues, and the association of PFN1 expression with patient clinicopathological characteristics was analyzed. PFN1 was knocked down to investigate the role of this protein in cell proliferation and metastasis in the SGC-7901 cell line. To explore the underlying mechanisms, the expression of integrin β1 and the activity of focal adhesion kinase (FAK) and the downstream proteins extracellular-regulated kinase (ERK)1/2, P38 mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K), AKT and mammalian target of rapamycin (mTOR) were measured through Western blot or qRT-PCR analysis. Fibronectin (FN), a ligand of integrin β1, was used to verify the correlation between alterations in the integrin β1/FAK pathway and changes in tumor cell aggressiveness upon PFN1 perturbation.

RESULTS: Immunohistochemical, Western blot and qRT-PCR analyses revealed that PFN1 expression was higher at both the protein and mRNA levels in gastric carcinoma tissues compared with the adjacent tissues. In addition, high PFN1 expression (53/75, 70.4%) was correlated with tumor infiltration, lymph node metastasis and TNM stage in gastric cancer, but not with gender, age, location, tumor size, or histological differentiation. In vitro experiments showed that PFN1 knockdown inhibited the proliferation of SGC-7901 cells through the induction G₀/G₁ arrest. Silencing PFN1 inhibited cell migration and invasion and down-regulated the expression of matrix metalloproteinase (MMP)-2 and MMP9. Moreover, silencing PFN1 reduced the expression of integrin β1 at the protein level and inhibited the activity of FAK, and the downstream effectors ERK1/2, P38MAPK, PI3K, AKT and mTOR. FN-promoted cell proliferation and metastasis via the integrin β1/FAK pathway was ameliorated by PFN1 silencing.

CONCLUSION: These findings suggest that PFN1 plays a critical role in gastric carcinoma progression, and these effects are likely mediated through the integrin β1/FAK pathway.

Downregulation of MTSS1 expression is an independent prognosticator in squamous cell carcinoma of the lung

Background:

The metastasis suppressor 1 (MTSS1) is a newly discovered protein putatively involved in tumour progression and metastasis.

Material and Methods:

Immunohistochemical expression of MTSS1 was analysed in 264 non-small-cell lung carcinomas (NSCLCs).

Results:

The metastasis suppressor 1 was significantly overexpressed in NSCLC compared with normal lung (P=0.01). Within NSCLC, MTSS1 expression was inversely correlated with pT-stage (P=0.019) and histological grading (P<0.001). NSCLC with MTSS1 downregulation (<20%) showed a significantly worse outcome (P=0.007). This proved to be an independent prognostic factor in squamous cell carcinomas (SCCs; P=0.041), especially in early cancer stages (P=0.006).

Conclusion:

The metastasis suppressor 1 downregulation could thus serve as a stratifying marker for adjuvant therapy in early-stage SCC of the lung.

SCF β-TRCP targets MTSS1 for ubiquitination-mediated destruction to regulate cancer cell proliferation and migration

Metastasis suppressor 1 (MTSS1) is an important tumor suppressor protein, and loss of MTSS1 expression has been observed in several types of human cancers. Importantly, decreased MTSS1 expression is associated with more aggressive forms of breast and prostate cancers, and with poor survival rate. Currently, it remains unclear how MTSS1 is regulated in cancer cells, and whether reduced MTSS1 expression contributes to elevated cancer cell proliferation and migration. Here we report that the SCF^β-TRCP regulates MTSS1 protein stability by targeting it for ubiquitination and subsequent destruction via the 26S proteasome. Notably, depletion of either Cullin 1 or β-TRCP1 led to increased levels of MTSS1. We further demonstrated a crucial role for Ser322 in the DSGXXS degron of MTSS1 in governing SCF^β-TRCP-mediated MTSS1 degradation. Mechanistically, we defined that Casein Kinase Iδ (CKIδ) phosphorylates Ser322 to trigger MTSS1's interaction with β-TRCP for subsequent ubiquitination and degradation. Importantly, introducing wild-type MTSS1 or a non-degradable MTSS1 (S322A) into breast or prostate cancer cells with low MTSS1 expression significantly inhibited cellular proliferation and migration. Moreover, S322A-MTSS1 exhibited stronger effects in inhibiting cell proliferation and migration when compared to ectopic expression of wild-type MTSS1. Therefore, our study provides a novel molecular mechanism for the negative regulation of MTSS1 by β-TRCP in cancer cells. It further suggests that preventing MTSS1 degradation could be a possible novel strategy for clinical treatment of more aggressive breast and prostate cancers.

Expression of metastasis suppressor 1 in cervical carcinoma and the clinical significance

This study aimed to investigate the expression of metastasis suppressor 1 (MTSS1) in cervical intraepithelial neoplasia (CIN) and malignant cervical tissues, and the role of MTSS1 in carcinogenesis. MTSS1 expression was detected by immunohistochemistry in 147 cervical tissue specimens collected from 30 healthy individuals, 30 patients with cervical CIN I, 30 patients with CIN II–III and 57 patients with cervical cancer. The association between MTSS1 expression and clinicopathological factors was also examined. MTSS1 was found to be positively expressed in 43.33% CIN I cervical tissues, 100% CIN II–III cervical tissues and 100% malignant cervical tissues, but was weakly or negatively expressed in benign cervical tissues. The positive expression rates of MTSS1 were significantly higher in CIN II–III and malignant cervical tissues than in CIN I or normal cervical tissues (P<0.05). When examining MTSS1 expression and clinicopathological factors, the strong positive MTSS1 expression rates in early-stage versus middle- and advanced-stage cervical cancer tissues were 39.13% and 82.35%, respectively. Furthermore, the positive expression rates of MTSS1 were significantly higher in cervical tissues at an advanced clinical stage than those at an early clinical stage (P<0.05). The results suggest that the dysregulation of MTSS1 may be involved in cervical carcinogenesis, and thus MTSS1 may be a novel diagnostic biomarker or therapeutic target in cervical cancer patients.

MicroRNA-182 drives metastasis of primary sarcomas by targeting multiple genes

Metastasis causes most cancer deaths, but is incompletely understood. MicroRNAs can regulate metastasis, but it is not known whether a single miRNA can regulate metastasis in primary cancer models in vivo. We compared the expression of miRNAs in metastatic and nonmetastatic primary mouse sarcomas and found that microRNA-182 (miR-182) was markedly overexpressed in some tumors that metastasized to the lungs. By utilizing genetically engineered mice with either deletion of or overexpression of miR-182 in primary sarcomas, we discovered that deletion of miR-182 substantially decreased, while overexpression of miR-182 considerably increased, the rate of lung metastasis after amputation of the tumor-bearing limb. Additionally, deletion of miR-182 decreased circulating tumor cells (CTCs), while overexpression of miR-182 increased CTCs, suggesting that miR-182 regulates intravasation of cancer cells into the circulation. We identified 4 miR-182 targets that inhibit either the migration of tumor cells or the degradation of the extracellular matrix. Notably, restoration of any of these targets in isolation did not alter the metastatic potential of sarcoma cells injected orthotopically, but the simultaneous restoration of all 4 targets together substantially decreased the number of metastases. These results demonstrate that a single miRNA can regulate metastasis of primary tumors in vivo by coordinated regulation of multiple genes.

MicroRNA-135a inhibits cell proliferation by targeting Bmi1 in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal solid tumor due to the lack of reliable early detection markers and effective therapies. MicroRNAs (miRNAs), noncoding RNAs that regulate gene expression, are involved in tumorigenesis and have a remarkable potential for the diagnosis and treatment of malignancy. In this study, we investigated aberrantly expressed miRNAs involved in PDAC by comparing miRNA expression profiles in PDAC cell lines with a normal pancreas cell line and found that miR-135a was significantly down-regulated in the PDAC cell lines. The microarray results were validated by qRT-PCR in PDAC tissues, paired adjacent normal pancreatic tissues, PDAC cell lines, and a normal pancreas cell line. We then defined the tumor-suppressing significance and function of miR-135a by constructing a lentiviral vector to express miR-135a. The overexpression of miR-135a in PDAC cells decreased cell proliferation and clonogenicity and also induced G1 arrest and apoptosis. We predicted Bmi1 may be a target of miR-135a using bioinformatics tools and found that Bmi1 expression was markedly up-regulated in PDAC. Its expression was inversely correlated with miR-135a expression in PDAC. Furthermore, a luciferase activity assay revealed that miR-135a could directly target the 3'-untranslated region (3'-UTR) of Bmi1. Taken together, these results demonstrate that miR-135a targets Bmi1 in PDAC and functions as a tumor suppressor. miR-135a may offer a new perspective for the development of effective miRNA-based therapy for PDAC.

Anti-proliferation effects of interferon-gamma on gastric cancer cells

IFN-γ plays an indirect anti-cancer role through the immune system but may have direct negative effects on cancer cells. It regulates the viability of gastric cancer cells, so we examined whether it affects their proliferation and how that might be brought about. We exposed AGS, HGC-27 and GES-1 gastric cancer cell lines to IFN-γ and found significantly reduced colony formation ability. Flow cytometry revealed no effect of IFN-γ on apoptosis of cell lines and no effect on cell aging as assessed by β-gal staining. Microarray assay revealed that IFN-γ changed the mRNA expression of genes related to the cell cycle and cell proliferation and migration, as well as chemokines and chemokine receptors, and immunity-related genes. Finally, flow cytometry revealed that IFN-γ arrested the cells in the G1/S phase. IFN-γ may slow proliferation of some gastric cancer cells by affecting the cell cycle to play a negative role in the development of gastric cancer.

Increased expression of phospho-acetyl-CoA carboxylase protein is an independent prognostic factor for human gastric cancer without lymph node metastasis

Upregulation of acetyl-CoA carboxylase (ACC), as a rate-limiting enzyme of fatty acid synthesis,has been recognized in multiple human cancers, implicating a critical role in cancer development and progression; yet, its role in gastric cancer still remains unclear. In the present study, we detected ACC and phosphorylated form of ACC (pACC) expression in gastric cancers and explored its clinical significance. Tissue microarray blocks containing primary gastric cancer and adjacent normal mucosa specimens obtained from 1,072 Chinese patients were used for the detection of ACC and pACC expression by immunohistochemistry. Gastric cancer cell lines were treated by metformin, and pACC was measured by Western blotting. ACC overexpression was observed in all the tumor specimens. High expression of pACC was found in 630 (58.8 %) of the 1,072 primary tumors and in 237 (66.6 %) of the 356 primary tumors without lymph node metastasis. Absent/low expression of pACC significantly correlated with advanced T stage (P < 0.001), tumor size (P = 0.010), lymph node metastasis (P < 0.001), advanced disease stage (P < 0.001), and poor histological differentiation (P = 0.014) in 1,072 primary tumors, and with advanced T stage (P = 0.015), tumor size (P = 0.017), and poor histological differentiation (P = 0.001) in 356 tumors without lymph node metastasis. Kaplan-Meier analysis showed that high expression of pACC is strongly related to better survival rates in all gastric cancer patients (P = 0.006). Cox regression analysis revealed that pACC is an independent prognostic factor only in patients without lymph node metastasis (P = 0.016). Metformin treatment leaded to increased expression of pACC, which, in turn, resulted in the reduction of cell proliferation and colony formation of gastric cancer cells (P < 0.05). Increased activation of ACC is frequent in human gastric cancer, and downregulation of pACC is an important prognostic factor, suggesting that ACC/pACC might be a potential target for cancer intervention.