The significance of MMP-1 and MMP-2 in peritoneal disseminated metastasis of gastric cancer

Role of NOX1 and NOX5 in protein kinase C/reactive oxygen species‑mediated MMP‑9 activation and invasion in MCF‑7 breast cancer cells

NADPH oxidases (NOXs) are a family of membrane proteins responsible for intracellular reactive oxygen species (ROS) generation by facilitating electron transfer across biological membranes. Despite the established activation of NOXs by protein kinase C (PKC), the precise mechanism through which PKC triggers NOX activation during breast cancer invasion remains unclear. The present study aimed to investigate the role of NOX1 and NOX5 in the invasion of MCF‑7 human breast cancer cells. The expression and activity of NOXs and matrix metalloprotease (MMP)‑9 were assessed by reverse transcription‑quantitative PCR and western blotting, and the activity of MMP‑9 was monitored using zymography. Cellular invasion was assessed using the Matrigel invasion assay, whereas ROS levels were quantified using a FACSCalibur flow cytometer. The findings suggested that NOX1 and NOX5 serve crucial roles in 12‑O‑tetradecanoylphorbol‑13‑acetate (TPA)‑induced MMP‑9 expression and invasion of MCF‑7 cells. Furthermore, a connection was established between PKC and the NOX1 and 5/ROS signaling pathways in mediating TPA‑induced MMP‑9 expression and cellular invasion. Notably, NOX inhibitors (diphenyleneiodonium chloride and apocynin) significantly attenuated TPA‑induced MMP‑9 expression and invasion in MCF‑7 cells. NOX1‑ and NOX5‑specific small interfering RNAs attenuated TPA‑induced MMP‑9 expression and cellular invasion. In addition, knockdown of NOX1 and NOX5 suppressed TPA‑induced ROS levels. Furthermore, a PKC inhibitor (GF109203X) suppressed TPA‑induced intracellular ROS levels, MMP‑9 expression and NOX activity in MCF‑7 cells. Therefore, NOX1 and NOX5 may serve crucial roles in TPA‑induced MMP‑9 expression and invasion of MCF‑7 breast cancer cells. Furthermore, the present study indicated that TPA‑induced MMP‑9 expression and cellular invasion were mediated through PKC, thus linking the NOX1 and 5/ROS signaling pathways. These findings offer novel insights into the potential mechanisms underlying their anti‑invasive effects in breast cancer.

The mechanism of L1 cell adhesion molecule interacting with protein tyrosine kinase 2 to regulate the focal adhesion kinase-growth factor receptor-bound protein 2-son of sevenless-rat sarcoma pathway in the identification and treatment of type I high-risk endometrial cancer

Objective

The objective of this study was to investigate how L1 cell adhesion molecule (L1CAM) interacting with protein tyrosine kinase 2 (PTK2) affects endometrial cancer (EC) progression and determine its association with the focal adhesion kinase (FAK)-growth factor receptor-bound protein 2 (GRB2)-son of sevenless (SOS)-rat sarcoma (RAS) pathway. EC is a female cancer of major concern in the world, and its incidence has increased rapidly in recent years. L1CAM is considered a reliable marker of poor prognosis in patients with EC.

Material and Methods

A single-center and prospective study was conducted using data from the Cancer Genome Atlas and samples from normal and EC tissues to explore the differential expression of L1CAM. Additional experimental models included human immortalized endometrial epithelium cells (hEECs) and EC cell lines such as KLE, RL95-2, and Ishikawa. L1CAM expression was regulated using lentiviruses designed for either overexpression or interference, and PTK2/focal adhesion kinase (FAK) signaling was inhibited with PF431396. Transfected KLE cells were injected into mice, and tumor growth was monitored over 14 days. Cellular proliferation and survival were assessed using cell counting kit, colony formation, and terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate (dUTP) nick-end labeling assays. Metastatic behavior was evaluated through Transwell assays for cell migration and invasion. The expression levels of matrix metallopeptidase (MMP) 2 and MMP9 were determined by Western blot. In addition, the activation of the FAK-GRB2-SOS-RAS pathway was examined by assessing the protein levels of FAK, GRB2, SOS, and RAS.

Results

There was a significant difference in L1CAM expression between EC tumor tissues and normal tissues, and L1CAM messenger RNA (1.85-fold) and L1CAM protein (2.59-fold) were significantly more expressed in EC tissues (P < 0.01) than in normal tissues. The tumor growth of L1CAM overexpressing EC cells was faster than that of negative control EC cells (6.43 fold; P < 0.001). L1CAM promoted the expression of FAK (1.43-2.72-fold; P < 0.001); enhanced EC cell proliferation (P < 0.01), survival and motility (P < 0.001), migration (P < 0.001), and invasion (P < 0.001); and activated the FAK-GRB2-SOS-RAS pathway, all of which were reversed when FAK expression was not upregulated (P < 0.001).

Conclusion

By upregulating PTK2 and its encoded protein FAK, L1CAM was found to promote tumor progression and increase the activation of the FAK-GRB2-SOS-RAS pathway. These findings establish L1CAM and PTK2 as reference genes for poor prognostic prediction in EC and as targets for EC therapy, providing a valuable basis for distinguishing between benign and malignant endometrial conditions and justifying the necessity of targeted therapeutic approaches.

Quantitative Expression of Key Cancer Markers in the AS-30D Hepatocarcinoma Model

Hepatocellular carcinoma is one of the cancers with the highest mortality rate worldwide. HCC is often diagnosed when the disease is already in an advanced stage, making the discovery and implementation of biomarkers for the disease a critical aim in cancer research. In this study, we aim to quantify the transcript levels of key signaling molecules relevant to different pathways known to participate in tumorigenesis, with special emphasis on those related to cancer hallmarks and epithelial-mesenchymal transition, using as a model the murine transplantable hepatocarcinoma AS-30D. Using qPCR to quantify the mRNA levels of genes involved in tumorigenesis, we found elevated levels for Tgfb1 and Spp1, two master regulators of EMT. A mesenchymal signature profile for AS-30D cells is also supported by the overexpression of genes encoding for molecules known to be associated to aggressiveness and metastatic phenotypes such as Foxm1, C-met, and Inppl1. This study supports the use of the AS-30D cells as an efficient and cost-effective model to study gene expression changes in HCC, especially those associated with the EMT process.

Extracellular matrix mediates moruloid-blastuloid morphodynamics in malignant ovarian spheroids

Ovarian cancer metastasizes into peritoneum through dissemination of transformed epithelia as multicellular spheroids. Harvested from the malignant ascites of patients, spheroids exhibit startling features of organization typical to homeostatic glandular tissues: lumen surrounded by smoothly contoured and adhered epithelia. Herein, we demonstrate that cells of specific ovarian cancer lines in suspension, aggregate into dysmorphic solid "moruloid" clusters that permit intercellular movement, cell penetration, and interspheroidal coalescence. Moruloid clusters subsequently mature into "blastuloid" spheroids with smooth contours, a temporally dynamic lumen and immotile cells. Blastuloid spheroids neither coalesce nor allow cell penetration. Ultrastructural examination reveals a basement membrane-like extracellular matrix coat on the surface of blastuloid, but not moruloid, spheroids. Quantitative proteomics reveals down-regulation in ECM protein Fibronectin-1 associated with the moruloid-blastuloid transition; immunocytochemistry also confirms the relocalization of basement membrane ECM proteins: collagen IV and laminin to the surface of blastuloid spheroids. Fibronectin depletion accelerates, and enzymatic basement membrane debridement impairs, lumen formation, respectively. The regulation by ECM dynamics of the morphogenesis of cancer spheroids potentially influences the progression of the disease.

A Network Pharmacological Approach to Reveal the Pharmacological Targets and Its Associated Biological Mechanisms of Prunetin-5-O-Glucoside against Gastric Cancer

Simple Summary

Identification of pharmacological targets in cancer provides a major walkthrough toward treatment strategies. The present research adopted a network pharmacology approach utilizing a flavonoid glucoside prunetin-5-O-glucoside (PG) compound against gastric cancer. The correlative targets were analyzed using Swiss target prediction and DiGeNET databases. Functional enrichment and significant pathways enriched were predicted for the targets to associate its biological mechanisms with cancer. Protein interaction network and cluster analysis was performed using Search Tool for the Retrieval of Interacting Genes/Proteins (STRING). Our analysis revealed three core targets among the clustered modules that plays a crucial role in relation with cancer. With this information, the core targets were examined for the binding affinity with PG using molecular docking analysis and validations on the protein targets was performed using western blot analysis and Human Protein Atlas. Our analysis through comprehensive network pharmacology resulted in the prediction of three core targets of PG that can be significant biomarkers against gastric cancer.

Abstract

Gastric cancer (GC) is an aggressive malignancy with increased mortality rate and low treatment options. Increasing evidence suggests that network pharmacology will be a novel method for identifying the systemic mechanism of therapeutic compounds in diseases like cancer. The current study aimed to use a network pharmacology approach to establish the predictive targets of prunetin-5-O-glucoside (PG) against gastric cancer and elucidate its biological mechanisms. Primarily, genes associated with the pathogenesis of GC was identified from the DiGeNET database and targets of PG was obtained from the Swiss target prediction database. In total, 65 correlative hits were identified as anti-gastric cancer targets of PG. Functional enrichment and pathway analysis revealed significant biological mechanisms of the targets. Interaction of protein network and cluster analysis using STRING resulted in three crucial interacting hub targets namely, HSP90AA1, CDK2, and MMP1. Additionally, the in vitro cytotoxic potential of PG was assessed on three gastric cancer cells (AGS, MKN-28, and SNU-484). Furthermore, the crucial targets were validated using molecular docking, followed by their expressions being evaluated by western blot and Human Protein Atlas. The findings indicate that the pharmacological action of PG against GC might be associated with the regulation of three core targets: HSP90AA1, CDK2, and MMP1. Thus, the network pharmacology undertaken in the current study established the core active targets of PG, which may be extensively applied with further validations for treatment in GC.

Novel therapeutic compounds for prostate adenocarcinoma treatment: An analysis using bioinformatic approaches and the CMap database

INTRODUCTION

Prostate adenocarcinoma is the most frequently diagnosed malignancy, particularly for people >70 years old. The main challenge in the treatment of advanced neoplasm is bone metastasis and therapeutic resistance for known oncology drugs. Novel treatment methods to prolong the survival time and improve the life quality of these specific patients are required. The present study attempted to screen potential therapeutic compounds for the tumor through bioinformatics approaches, in order to provide conceptual treatment for this malignant disease.

METHODS

Differentially expressed genes were obtained from the Gene Expression Omnibus database and submitted into the Connectivity Map database for the detection of potentially associated compounds. Target genes were extracted from the search results. Functional annotation and pathway enrichment were performed for the confirmation. Survival analysis was used to measure potential therapeutic effects.

RESULTS

It was revealed that 3 compounds (vanoxerine, tolnaftate, and gabexate) may help to prolong the disease-free survival time from tumor metastasis of patients with the tumor. A total of 6 genes [also-keto reductase family 1 member C3 (AKR1C3), collagen type III α 1 chain (COL3A1), lipoprotein lipase (LPL), glucuronidase, β pseudogene 11 (GUSBP11), apolipoprotein E (APOE), and collagen type I α 1 chain (COL1A1)] were identified to be the potential therapeutic targets for the aforementioned compounds.

CONCLUSION

In the present study, it was speculated that 3 compounds may function as the potential therapeutic drugs of bone metastatic prostate adenocarcinoma; however, further studies verifying vitro and in vivo are necessary.

Molecular mediators of peritoneal metastasis in pancreatic cancer

Pancreatic cancer is the third leading cause of cancer death in the USA, and pancreatic ductal adenocarcinoma (PDA) constitutes 85% of pancreatic cancer diagnoses. PDA frequently metastasizes to the peritoneum, but effective treatment of peritoneal metastasis remains a clinical challenge. Despite this unmet need, understanding of the biological mechanisms that contribute to development and progression of PDA peritoneal metastasis is sparse. By contrast, a vast number of studies have investigated mechanisms of peritoneal metastasis in ovarian and gastric cancers. Here, we contrast similarities and differences between peritoneal metastasis in PDA as compared with those in gastric and ovarian cancer by outlining molecular mediators involved in each step of the peritoneal metastasis cascade. This review aims to provide mechanistic insights that could be translated into effective targeted therapies for patients with peritoneal metastasis from PDA.

Golgi Membrane Protein 1 (GOLM1) Promotes Growth and Metastasis of Breast Cancer Cells via Regulating Matrix Metalloproteinase-13 (MMP13)

Background

Breast cancer (BC) is the leading cause of death in women worldwide. Golgi membrane protein 1 (GOLM1) has been identified as novel regulator in carcinogenesis, but its function in BC is unclear.

Material/Methods

The expression of GOLM1 in BC tissues and cell lines was detected by using qRT-PCR assay. CCK-8 and colony-formation assays were used to evaluate BC cell growth in vivo. Wound-healing and Transwell assays were used to detect cell migration and invasion. To investigate GOLM1 functions in vivo, we established a xenograft mice model and a lung metastasis model. The level of epithelial-to-mesenchymal transition (EMT)-related markers was analyzed by immunofluorescent staining.

Result

GOLM1 was overexpressed in BC cell lines and tissues. Overexpression of GOLM1 induced EMT and promoted proliferation, migration, and invasion of BC cells. Furthermore, overexpressing of GOLM1 markedly promoted the tumorigenicity and metastasis of BC cells in vivo, whereas knock-down of GOLM1 caused the opposite outcomes. Furthermore, we proved that GOLM1 promoted BC cell aggressiveness by regulating matrix metalloproteinase-13 (MMP13).

Conclusions

Our results prove that GOLM1 facilitates the growth and metastasis of breast cancer cells.

Geraniin inhibits migration and invasion of human osteosarcoma cancer cells through regulation of PI3K/Akt and ERK1/2 signaling pathways

Geraniin, an active compound isolated from Geranium sibiricum, was found to inhibit proliferation and induce apoptosis of tumor cells. However, the antimetastatic effects of geraniin remain elusive. Our study found the potential antitumor mechanisms of geraniin through inhibiting the migration and invasion of human osteosarcoma U2OS cells. The western blot, gelatin zymography, and reversed transcription-PCR analysis showed that geraniin suppressed matrix metalloproteinase-9 (MMP-9) expression in a concentration-dependent manner. Geraniin potently suppressed the phosphorylation of extracellular signal regulating kinase (ERK)1/2, phosphatidylinositide-3-kinase (PI3K), and Akt, but did not affect phosphorylation of p38 mitogen-activated protein kinase and c-Jun N-terminal kinase. Furthermore, when transforming growth factor-β1 (TGF-β1) was used as an agonist, geraniin inhibited TGF-β1-mediated cell invasion and upregulation of MMP-9. These results suggested that geraniin inhibited U2OS cell migration and invasion by reducing the expression of MMP-9 through the PI3K/Akt and ERK1/2 signaling pathways.

Antimetastatic effects of Rheum palmatum L. extract on oral cancer cells

Rheum palmatum L., a traditional Chinese medication, has been used for the treatment of various disorders. However, the detailed impacts and underlying mechanisms of R. palmatum L. extracts (RLEs) on human oral cancer cell metastasis are still unclear. Here, we tested the hypothesis that an RLE has antimetastatic effects on SCC-9 and SAS human oral cancer cells. Gelatin zymography, Western blot, real-time polymerase chain reaction, and luciferase assay were used to explore the underlying mechanisms involved in the antimetastatic effects on oral cancer cells. Our results revealed that the RLE (up to 20 μg/mL, without cytotoxicity) attenuated SCC-9 and SAS cell motility, invasiveness, and migration by reducing matrix metalloproteinase (MMP)-2 enzyme activities. Western blot analysis of the MAPK signaling pathway indicated that the RLE significantly decreased phosphorylated ERK1/2 levels but not p38 and JNK levels. In conclusion, RLEs exhibit antimetastatic activity against oral cancer cells through the transcriptional repression of MMP-2 via the Erk1/2 signaling pathways. Thus, RLEs may be potentially useful as antimetastatic agents for oral cancer chemotherapy.

Cucurbitacin B inhibits cell proliferation and induces apoptosis in human osteosarcoma cells via modulation of the JAK2/STAT3 and MAPK pathways

Osteosarcoma (OS) is the most commonly diagnosed tumor of the bones in children and young adults. Even with conventional therapies the 5-year survival rate is ~65% in patients with OS. Considering the side effects and aggressiveness of malignant bone tumors, research is focussing on multi-targeted strategies in treatment. Cucurbitacin B, a triterpenoid compound has been demonstrated to induce apoptosis in various cancer cell types. The Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signalling cascades and mitogen activated protein kinases (MAPK) signalling cascades are critical regulators of tumorigenesis. The present study assessed the influence of cucurbitacin B on the viability and expression of MAPKs and proteins of the JAK2/STAT3 cascades in human OS cells (U-2 OS). Cucurbitacin B (20-100 µM) significantly reduced cell viability (P<0.05) and induced apoptosis, as assessed by MTT and Annexin V/propidium iodide staining, along with inhibiting cell migration. Gelatin zymography revealed supressed activities of matrix metalloproteinase (MMP-)2 and 9. Furthermore, cucurbitacin B effectively upregulated the apoptotic pathway and caused the effective inhibition of MAPK signalling and JAK2/STAT3 cascades. Multifold suppression of vascular endothelial growth factor by cucurbitacin B was also observed, indicating inhibition of angiogenesis. Thus, by downregulating major pathways-MAPK and JAK2/STAT3 and MMPs, cucurbitacin B has potent anti-proliferative and anti-metastatic effects that require further investigation with regards to cancer treatment.

The Mesothelial Origin of Carcinoma Associated-Fibroblasts in Peritoneal Metastasis

Solid tumors are complex and unstructured organs that, in addition to cancer cells, also contain other cell types. Carcinoma-associated fibroblasts (CAFs) represent an important population in the tumor microenviroment and participate in several stages of tumor progression, including cancer cell migration/invasion and metastasis. During peritoneal metastasis, cancer cells detach from the primary tumor, such as ovarian or gastrointestinal, disseminate through the peritoneal fluid and colonize the peritoneum. Tumor cells metastasize by attaching to and invading through the mesothelial cell (MC) monolayer that lines the peritoneal cavity, then colonizing the submesothelial compact zone where CAFs accumulate. CAFs may derive from different sources depending on the surrounding metastatic niche. In peritoneal metastasis, a sizeable subpopulation of CAFs originates from MCs through a mesothelial-to-mesenchymal transition (MMT), which promotes adhesion, invasion, vascularization and subsequent tumor growth. The bidirectional communication between cancer cells and MC-derived CAFs via secretion of a wide range of cytokines, growth factors and extracellular matrix components seems to be crucial for the establishment and progression of the metastasis in the peritoneum. This manuscript provides a comprehensive review of novel advances in understanding how peritoneal CAFs provide cancer cells with a supportive microenvironment, as well as the development of future therapeutic approaches by interfering with the MMT in the peritoneum.

The anthelmintic drug mebendazole inhibits growth, migration and invasion in gastric cancer cell model

The present study aimed to investigate the effects of MBZ on a human malignant ascites cell line derived from a primary gastric cancer tumor. Our data reveal that MBZ showed high cytotoxicity in vitro, displaying an IC50 of 0.39 μM and 1.25 μM in ACP-02 and ACP-03, respectively. The association between MBZ and 5-FU increased slightly the cytotoxicity when compared to MBZ and 5-FU alone. Furthermore, MBZ disrupted the microtubule structure of AGP-01 cells and inhibited significantly the invasion and migration of these cells. Activity of active MMP-2 significantly decreased at all tested concentration of MBZ compared to negative control. These results support the indication of MBZ in combination with chemotherapeutic agents as a possible adjuvant therapy for the management/treatment of patients with advanced gastric cancer since MBZ is a drug of low cost with acceptable safety profile and reduced toxicity to normal cells. However, clinical trials must be performed in o to evaluate its efficacy in gastric cancer patients.

Possible contribution of aminopeptidase N (APN/CD13) to migration and invasion of human osteosarcoma cell lines

Osteosarcoma is the most common primary malignancy of the bone. Aminopeptidase N (APN/CD13), a Zn+2-dependent ectopeptidase localized on the cell surface, is widely considered to influence the invasion mechanism. This study explores the potential involvement of APN in migration and invasion of human osteosarcoma cells in vitro using inhi-bitors and activators of APN. Cells treated with APN inhibitor bestatin displayed decreased migration and invasion in a Boyden chamber Transwell assay. Western blotting revealed reduced levels of mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K) pathway proteins, reduced phosphorylation of p38, ERK1/2 and JNK and decreased levels of NF-κB. Bestatin treatment also lowered APN, matrix metalloproteinase (MMP)-2 and -9 enzymatic activity and their mRNA expression. Reduced MMP-2 and -9 protein levels were also observed. By comparison, cells treated with cytokine interleukin-6 (IL-6), a stimulator of APN, displayed increased migration and invasion. Western blotting revealed increased levels of MAPK and PI3K pathway proteins, phosphorylated p38, ERK1/2 and JNK, and NF-κB. IL-6 treatment also increased APN and MMP-2 and -9 enzymatic activity. An increase of APN, MMP-2 and -9 mRNA levels, and MMP-2 and -9 protein levels was also observed. Together these experiments reveal potential enzymatic and signalling roles for APN in osteosarcoma and establish a starting point for an in-depth analysis of the role of APN in regulating invasiveness. A deeper knowledge about the regulatory mechanisms of APN may contribute to the development of anti-metastatic therapies.

Bufalin-inhibited migration and invasion in human osteosarcoma U-2 OS cells is carried out by suppression of the matrix metalloproteinase-2, ERK, and JNK signaling pathways

Bufalin has been shown to exhibit multiple pharmacological activities, including induction of apoptosis in many types of cancer cell lines. Osteosarcoma is a type of cancer which is difficult to treat and the purpose of this study was to investigate the effects of bufalin on the migration and invasion of human osteosarcoma U-2 OS cells. The wound healing assay and Boyden chamber transwell assay were used for examining the migration of U-2 OS cells. Western blotting and gelatin zymography assays were used for theexpression and activities of metalloproteinase (MMP)-2, MMP-7 or MMP-9 levels. Western blotting analysis also was used for measuring the levels of growth factor receptor-bound protein 2 (GRB2), son of sevenless homolog 1 (SOS1), c-Jun N-terminal kinases 1/2 (JNK1/2), extracellular signal-regulated kinase 1/2 (ERK1/2), and p38 in bufalin-treated U-2 OS cells. Bufalin inhibited the cell migration and invasion of U-2 OS cells in vitro. Moreover, bufalin reduced MMP-2 and MMP-9 enzyme activities of U-2 OS cells. Bufalin also suppressed the protein level of MMP-2 and reduced the levels of mitogen-activated protein kinases (MAPKs) such as JNK1/2 and ERK1/2 signals in U-2 OS cells. Our results suggest that signaling pathways for bufalin-inhibited migration and invasion of U-2 OS cells might be mediated through blocking MAPK signaling and resulting in the inhibition of MMP-2. Bufalin could be a useful agent to develop as a novel antitumor agent by virtue of its ability to inhibit tumor cell migration and invasion.

Molecular targeting therapy using bevacizumab for peritoneal metastasis from gastric cancer

AIM: To clarify the significance of vascular endothelial growth factor (VEGF) in peritoneal metastasis from gastric cancer, using the gastric cancer cell line MKN-45 compared with the high potential peritoneal dissemination gastric cancer cell line MKN-45P.

METHODS: The supernatant of culture medium of MKN-45 cells or MKN-45P cells was collected and the concentrations were measured of various cytokines, matrix metalloproteinases, growth factor and angiogenic factors, including VEGF. We performed an initial pilot study to explore whether bevacizumab, a humanized monoclonal antibody against VEGF, had any suppressive effect on the peritoneal dissemination from gastric cancer in an experimental nude mouse model of peritoneal metastasis.

RESULTS: The concentrations of interleukin-6 (IL-6), IL-8, VEGF and matrix metalloproteinase-2 protein in the culture supernatant were each significantly higher than each of those for MKN-45. In the in vivo study, the volume of ascites and the mitotic index were significantly lower in the therapy group than in the non-therapy group. The survival curve of the therapy group was significantly higher than that of the non-therapy group. These results suggested that VEGF was correlated with peritoneal metastasis from gastric cancer.

CONCLUSION: Findings suggested that bevacizumab for inhibiting VEGF could suppress peritoneal dissemination from gastric cancer.

Reoxygenation using a novel CO2 therapy decreases the metastatic potential of osteosarcoma cells

Osteosarcoma is the most common primary solid malignant bone tumor. Despite substantial improvements in surgery and chemotherapy, metastasis remains a major cause of fatal outcomes, and the molecular mechanisms of metastasis are still poorly understood. Hypoxia, which is common in malignant tumors including osteosarcoma, increases expressions of hypoxia inducible factor (HIF)-1α, matrix metalloproteinase (MMP)-2 and MMP-9, and can induce invasiveness. As we previously showed a novel transcutaneous CO2 application to decrease HIF-1α expression and induce apoptosis in malignant fibrous histiocytoma, we hypothesize that transcutaneous CO2 application could suppress metastatic potential of osteosarcoma by improving hypoxic conditions. Here, we examined the effects of transcutaneous CO2 application on apoptosis, and development of pulmonary metastasis using a highly metastatic osteosarcoma cell line, LM8. Transcutaneous CO2 application significantly decreased tumor growth and pulmonary metastasis in LM8 cells. Apoptotic activity increased, and intratumoral hypoxia was improved with decreased expressions of HIF-1α, MMP-2 and MMP-9, significantly, in the CO2-treated tumors. In conclusion, we found that transcutaneous CO2 application can induce tumor cell apoptosis and might suppress pulmonary metastasis by improvement of hypoxic conditions with decreased expressions of HIF-1α and MMPs in highly metastatic osteosarcoma cell. These findings strongly indicate that this novel transcutaneous CO2 therapy could be a therapeutic breakthrough for osteosarcoma patients.

Knockdown of hypoxia-inducible factor-1α accelerates peritoneal dissemination via the upregulation of MMP-1 expression in gastric cancer cell lines

This study was performed to clarify the role of hypoxia-inducible factor-1 α (HIF-1α) in the development of peritoneal dissemination in a xenograft mouse model of gastric cancer. HIF-1α knockdown (KD) and control (SC) gastric cancer cells, which were established using the MKN45 and MKN74 cell lines, were studied. The two paired cell lines were directly inoculated into the peritoneal cavity of nude mice. The number and the weight of disseminated nodules were compared between tumors generated from the KD and SC cells. In addition, the molecular mechanism was addressed through analysis of the expression levels of metastasis-related genes. The MKN45-KD cell line demonstrated significantly greater numbers of disseminated nodules and formed a larger tumor mass than the MKN45-SC cell line (p<0.05). MKN74-KD cells also tended to induce a greater number of nodules and to produce those with a heavier weight than the SC cells. An in vitro adhesion assay revealed differing results regarding the adhesion activity to extracellular matrix and monolayer mesothelium cells of the gastric cancer cells derived from the various parental cells. However, the expression of MMP-1 mRNA in the disseminated nodules was significantly increased in the KD cells compared to the SC cells derived from the two parental cell lines (p<0.01). An immunohisto-chemical study further demonstrated that there was stronger staining for MMP-1 in the MKN74-KD in comparison to MKN74-SC cells. Loss of HIF-1α may contribute to the development of aggressive peritoneal dissemination via the upregulation of MMP-1 in gastric cancer cells.

Comparison between the gastric cancer cell line MKN-45 and the high-potential peritoneal dissemination gastric cancer cell line MKN-45P

Peritoneal metastasis is the most common form of recurrence in gastric cancer, and is associated with a poor prognosis. It is clear that many agents are involved at the various stages of this process, however, many aspects of the progression remain unclear. In the present study we compared the gastric cancer cell line MKN-45 with the high-potential peritoneal dissemination gastric cancer cell line MKN-45P, established from MKN-45. The supernatant of culture medium of MKN-45 cells or MKN-45P cells was collected, and the concentrations of interleukin-1β (IL-1β), IL-6, IL-8, hepatocyte growth factor (HGF), Transforming growth factor beta-β1 (TGF-β1), vascular endothelial growth factor (VEGF), matrix metalloproteinase-2 (MMP-2), MMP-9, and tissue inhibitor of metalloproteinase-1 (TIMP-1) proteins were measured using an enzyme-linked immuno sorbent assay (ELISA) method. Invasion, wound healing and adhesion assays were performed in vitro to examine interstitial invasion, migration and adhesion in the gastric cancer cell lines. Moreover, Western blotting was performed to determine the expression of cyclooxygenase-1 (COX-1) and COX-2 proteins in the culture media of the cell lines. The concentrations of IL-6, IL-8, VEGF and MMP-2 protein in the culture supernatant of MKN-45P were significantly higher than those of MKN-45. Percent adhesion of MKN-45P was significantly higher than that of MKN-45 in the fibronectin-coated group. There was no significant difference in invasion or migration between MKN-45 and MKN-45P. COX-1 and COX-2 proteins were observed in both cell lines. These results suggested that secretion of IL-6, IL-8, VEGF and MMP-2 from cancer cells, and adhesion of cancer cells to fibronectin, were related to the establishment of peritoneal dissemination.

Gallic acid inhibits migration and invasion in human osteosarcoma U-2 OS cells through suppressing the matrix metalloproteinase-2/-9, protein kinase B (PKB) and PKC signaling pathways

Advanced cancer is a multifactorial disease which complicates treatment if the cancer cells have metastasized calling for the targeting of multiple cellular pathways. Gallic acid (GA) is known to possess multiple pharmacological activity including antitumor effects. This study investigated the mechanisms for the anticancer properties of GA on migration and invasion of human osteosarcoma U-2 OS cells. The migration and invasion in U-2 OS cells were determined by a Boyden chamber transwell assay. The expression levels and activities of MMP-2 and MMP-9 were measured by Western blotting, real-time PCR and gelatin zymography assays. All examined proteins levels from Western blotting indicated that GA decreased the protein levels of GRB2, PI3K, AKT/PKB, PKC, p38, ERK1/2, JNK, NF-κB p65 in U-2 OS cells. GA also inhibited the activities of AKT, IKK and PKC by in vitro kinase assay. GA suppressed the migration and invasive ability of U-2 OS cells, and it decreased MMP-2 and MMP-9 protein and mRNA levels and secreted enzyme activities in vitro. These results suggest that potential signaling pathways of GA-inhibited migration and invasion in U-2 OS cells may be due to down-regulation of PKC, inhibition of mitogen-activated protein kinase (MAPK) and PI3K/AKT, resulting in inhibition of MMP-2 and MMP-9 expressions.

Phenethyl isothiocyanate inhibited tumor migration and invasion via suppressing multiple signal transduction pathways in human colon cancer HT29 cells

Phenethyl isothiocyanate (PEITC), one of the major compounds from dietary cruciferous vegetables, has been found to have antitumor properties and therefore could generate special interest for the development of chemopreventive and/or chemotherapeutic agent for human cancers. In the primary studies, we found that PEITC induced cytotoxic effect (decreased the percentage of viable cells) in human colon cancer HT29 cells. Here, in this study, we are the first to report the antimetastatic effect of PEITC in HT29 human colon cancer cells. The results show that PEITC exhibited an inhibitory effect on the abilities of adhesion, migration, and invasion by Boyden chamber assay. Western blotting examination indicated that PEITC exerted an inhibitory effect on the SOS-1, PKC, ERK1/2 and Rho A for causing the inhibitions of MMP-2 and -9 then followed by the inhibition of invasion and migration of HT29 cells in vitro. PEITC also affected Ras, FAK, PI3K or inhibited GRB2, NF-κB, iNOS and COX-2 for causing the inhibition of cell proliferation in HT29 cells. Real-time PCR also showed that PEITC inhibited the gene expressions of MMP-2, -7, -9, FAK and Rho A after PEITC treatment for 48 h in HT29 cells. PEITC also inhibited the activities of AKT, ERK, JNK and PKC. Our results provide a new insight into the mechanisms and functions of PEITC which inhibit migration and invasion of HT29 human colon cancer cells. These results suggest that molecular targeting of NF-κB led to the inhibition of MMP-2, -7, and -9 and it might be a useful strategy for the inhibition of migration and invasion on human colon cancer.

Benzyl isothiocyanate (BITC) inhibits migration and invasion of human gastric cancer AGS cells via suppressing ERK signal pathways

Metastasis suppressors and associated other regulators of cell motility play a critical initial role in tumor invasion and metastases. Benzyl isothiocyanate (BITC) is a hydrolysis compound of glucotropaeolin in dietary cruciferous vegetables. BITC has been found to exhibit prevention of cancers in laboratory animals and might also be chemoprotective in humans. Here, the purpose of this study was to investigate the effects of BITC on cell proliferation, migration, invasion and mitogen-activated protein kinase (MAPK) pathways of AGS human gastric cancer cells. Wound healing and Boyden chamber (migration and invasion) assays demonstrated that BITC exhibited an inhibitory effect on the abilities of migration and invasion in AGS cancer cells. BITC suppressed cell migration and invasion of AGS cells in a dose-dependent manner. Results from Western blotting indicated that BITC exerted an inhibitory effect on the ERK1/2, Ras, GRB2, Rho A, iNOS, COX-2 for causing the inhibitions of MMP-2, -7 and -9 then followed by the inhibitions of invasion and migration of AGS cells in vitro. BITC also promoted MKK7, MEKK3, c-jun, JNK1/2, VEGF, Sos1, phosphoinositide 3-kinase (PI3K), PKC, nuclear factor-kappaB (NF-κB) p65 in AGS cells. Results from real-time polymerized chain reaction (PCR) showed that BITC inhibited the gene expressions of MMP-2,-7 -9, FAK, ROCK1 and RhoA after BITC treatment for 24 and 48 hours in AGS cells. Taken together, the finding may provide new mechanisms and functions of BITC, which inhibit migration and invasion of human gastric cancer AGS cells.

Pterostilbene inhibited tumor invasion via suppressing multiple signal transduction pathways in human hepatocellular carcinoma cells

Pterostilbene, a natural dimethylated analog of resveratrol, is known to have diverse pharmacologic activities including anticancer, anti-inflammation, antioxidant, apoptosis, anti-proliferation and analgesic potential. However, the effects of pterostilbene in preventing invasion of cancer cells have not been studied. Here, we report our finding that pterostilbene significantly suppressed 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced invasion, migration and metastasis of human hepatoma cells (HepG(2) cells). Increase in the enzyme activity, protein and messenger RNA levels of matrix metalloproteinase (MMP)-9 were observed in TPA-treated HepG(2) cells, and these were blocked by pterostilbene. In addition, pterostilbene can inhibit TPA-induced expression of vascular endothelial growth factor, epidermal growth factor and epidermal growth factor receptor. Transient transfection experiments also showed that pterostilbene strongly inhibited TPA-stimulated nuclear factor kappa B (NF-kappaB) and activator protein-1 (AP-1)-dependent transcriptional activity in HepG(2) cells. Moreover, pterostilbene can suppress TPA-induced activation of extracellular signal-regulated kinase 1/2, p38 mitogen-activated protein kinase, c-Jun N-terminal kinases 1/2 and phosphatidylinositol 3-kinase/Akt and protein kinase C that are upstream of NF-kappaB and AP-1. Significant therapeutic effects were further demonstrated in vivo by treating nude mice with pterostilbene (50 and 250 mg/kg intraperitoneally) after inoculation with HepG(2) cells into the tail vein. Presented data reveal that pterostilbene is a novel, effective, anti-metastatic agent that functions by downregulating MMP-9 gene expression.

The TIMP-1 gene transferred through adenovirus mediation shows a suppressive effect on peritoneal metastases from gastric cancer

BACKGROUND

It has become clear in recent years that peritoneal metastasis takes place as the result of a multistep process involving attachment, invasion, proliferation, and angiogenesis. The aim of the present study was to evaluate the suppressive effect of tissue inhibitor of metalloproteinase-1 (TIMP-1) gene transfer on peritoneal dissemination.

METHODS

We established a high-potential peritoneal metastasis cell line (MKN-45P), using the gastric cancer cell line MKN-45, and developed a peritoneal metastasis model in nude mice. The TIMP-1 gene was transferred to MKN-45 or MKN-45P by adenoviral transfection, and we performed an in vitro invasion assay and an in vivo study, using the peritoneal metastasis model. The TIMP-1 transfected group was compared with a non-virus group and a Lac-Z transfected group.

RESULTS

The in vitro invasion assay showed that the number of invasive cells was significantly reduced in the TIMP-1 transfected group compared with that in the non-virus group and the Lac-Z transfected group, Moreover, the in vivo studies showed that the number and the weight of the peritoneal nodes in the TIMP-1 transfected group were significantly less than those in the Lac-Z transfected group, and less than those in the non-viral group. No bloody ascites was recognized in the TIMP-1 transfected group. The mean number of tumor vessels in the non-virus group and the Lac-Z group was significantly higher than that in the TIMP-1 group.

CONCLUSION

TIMP-1 demonstrated an inhibitory effect on angiogenesis, and may be worthwhile investigating for use as a future therapy for peritoneal dissemination.

Optimal method for isolation of human peritoneal mesothelial cells from clinical samples of omentum

INTRODUCTION

Human peritoneal mesothelial cells (HPMC) are a valuable research tool for understanding the molecular biology of several pathologies, in both monolayer and three dimensional models. We compared different methods of HPMC isolation and assessed their outcome as well as fibroblast contamination, a common problem encountered during isolation.

METHODS

1-3cm(3) samples of omentum were collected from 40 consenting patients undergoing elective gastrointestinal surgery. A total of 11 samples were incubated in 0.05% trypsin solution for 20 minutes at 37 degrees C (group A) and 29 in 0.25% trypsin (15 samples for 10 minutes (group B) and 14 for 20 minutes (group C)). Following digestion cells were re-suspended and cultured in supplemented Ham's F-12 medium containing 10% foetal calf serum (FCS), penicillin-streptomycin, glutamine, insulin, transferrin and hydrocortisone. Positive outcomes were absence of fibroblast contamination and satisfactory HPMC growth to confluence in a characteristic cobblestone pattern. Cytokeratins 5, 8, 18, Vimentin, Ber-Ep4 and Factor VIII were used to characterise HPMC and fibroblasts by immunohistochemistry.

RESULTS

None of the 11 samples in group A yielded HPMC. 14 of 29 samples digested with 0.25% trypsin yielded HPMC: 10 of 14 yielded HPMC in group C versus four of 15 samples in group B (p = 0.02). Fibroblast contamination occurred in eight samples in group B versus three in group C.

CONCLUSION

Optimal results are achieved with a 20 minute digestion in 0.25% trypsin. Fibroblast contamination could not be avoided completely. Other factors may minimise fibroblast contamination such as minimal tissue manipulation and early collection during surgery.

Arsenic trioxide (As(2)O(3)) inhibits peritoneal invasion of ovarian carcinoma cells in vitro and in vivo

OBJECTIVES

To study the role of arsenic trioxide (As(2)O(3)) in regulating peritoneal invasive activity of ovarian carcinoma cells in vitro and in vivo.

METHODS

The effects of As(2)O(3) on human ovarian cancer cell lines (3AO, SW626 and HO-8910PM) migration, invasion and adhesion with tumor cells and human peritoneal mesothelial cells (HPMC) were observed by means of cell migration test, cell invasion test and cell adhesion test. The effects of As(2)O(3) on MMP-2, MMP-9, TIMP-1 and TIMP-2 gene expressions and protein expressions of tumor cells were determined by RT-PCR and ELISA, respectively. In animal experiments, ovarian tumor cells were implanted into abdominal cavity of nude mice and then the nude mice were treated by intraperitoneal injection of different doses As(2)O(3). The foci on the surface of peritoneum were counted.

RESULTS

As(2)O(3) inhibited tumor cells migration, invasion and adhesion with HPMC in a dose-dependent manner, while the same treatment enhanced tumor cell-tumor cell interactions. As(2)O(3) inhibited mRNA and protein expressions of MMP-2, MMP-9 and TIMP-2 of tumor cells. In contrast, As(2)O(3) increased mRNA and protein expressions of TIMP-1. As(2)O(3) could reduce tumor cells peritoneal metastasis in nude mice.

CONCLUSION

As(2)O(3) inhibits in vitro and in vivo peritoneal invasive activity of ovarian carcinoma cells in a dose-dependent manner. Its anti-invasive activity may be the results of reduced cell motility, inhibited attachment of tumor cells to HPMC and enhanced tumor cell-tumor cell interaction, as well as down-regulation of MMP-2 and MMP-9 levels and up-regulation of TIMP-1 level.

Relationship between matrix metalloproteinase-2 mRNA expression and clinicopathological and urokinase-type plasminogen activator system parameters and prognosis in human gastric cancer

AIM: To investigate the relationship between matrix metalloproteinase-2 (MMP-2) mRNA expression and clinicopathologic and urokinase-type plasminogen activator (uPA) system parameter and prognosis in human gastric cancer.

METHODS: Expression of MMP-2 mRNA, uPA, and uPA-R mRNA in tumor tissues and ≥5 cm adjacent normal tissues from 67 cases of gastric cancer was studied using RT-PCR and Northern blot respectively. Survival analyses were done using the Kaplan-Meier method.

RESULTS: The expression rates of MMP-2 mRNA, uPA and uPA-R mRNA in tumor tissues (31%, 41%, and 51%, respectively) were significantly higher than those in ≥5 cm adjacent tissues (19%, 11%, and 9%; χ² = 4.59, 43.58, and 53.24 respectively, P<0.05, 0.0001, and 0.0001, respectively). Expression of MMP-2 mRNA was significantly correlated with lymph node metastasis (metastasis: 61.9%, no metastasis: 39.1%, χ² = 7.61, P<0.05), Lauren’s classification of diffuse/mixed types: 54.2%, intestinal type: 26.3%, χ² = 4.25, P<0.05, expression of uPA and uPA-R mRNA (uPA+: 55.1%, uPA-: 22.2% and uPA-R+: 54.9%, uPA-R-: 18.8%, χ² = 5.72 and 6.40 respectively, P<0.05). Kaplan-Meier survival analysis of MMP-2 mRNA expression did not show significant difference in all 67 cases, but revealed an association of the expression of MMP-2 mRNA, uPA, and uPA-R mRNA with worse prognosis (P = 0.0083, 0.0160, and 0.0094, respectively).

CONCLUSION: MMP-2 may play an important role in the development of invasion and metastasis of gastric cancer.

Mitochondrial redox control of matrix metalloproteinases

Reactive oxygen species (ROS) are constantly generated in aerobic organisms during normal metabolism and in response to both internal and external stimuli. Imbalances in the production and removal of ROS have been hypothesized to play a causative role in numerous disease pathologies such as cancer, ischemia/reperfusion injury, and degenerative diseases such as photoaging, atherosclerosis, arthritis, and neurodegeneration. A feature often associated with these diseases is a malfunctioning of the connective tissue remodeling process due to increased activity of extracellular matrix-degrading metalloproteinases (MMPs). This review summarizes the evidence that implicates ROS as key regulators of MMP production and the importance of these interactions in disease pathologies.

Relation between CD44v9, MMP-2 and tumor invasion and metastasis in gastric cancer

AIM

To study the expression of matrix metalloproteinase CD₄₄v9, matrix metalloproteinase-2 (MMP-2) in gastric cancer and the corresponding adjacent normal tissues, to investigate the possible mechanism of tumor invasion and metastasis in gastric cancer.

METHODS

Tumor tissues and adjacent normal tissues in 40 cases of gastric cancer were detected by using reverse transcriptase-polymerase chain reaction (RT-PCR) for the expression of CD₄₄v9, MMP-2.

RESULTS

The expression of CD₄₄v9, MMP-2 in tumor tissues were higher than that in adjacent normal tissues, respectively(x² = 12.929, x² = 10.769, P≤0.001).The expression was related to tumor size, degree of differentiation, clinical staging.The expression of CD₄₄v9, MMP-2 mRNA in 17 gastric cancers with lymph node metastasis were higher than that in gastric cancer without lymph node metastasis (P<0.05). The expression of CD₄₄v9, MMP-2 correlated highly with gastric cancer (r = 0.6, P<0.001).

CONCLUSION

CD₄₄v9, MMP-2 were related to tumor invasion and metastasis in gastric cancer, and could be used as important indexes to predict invasion and metastasis of gastric cancer.

Transforming growth factor-beta1 produced by ovarian cancer cell line HRA stimulates attachment and invasion through an up-regulation of plasminogen activator inhibitor type-1 in human peritoneal mesothelial cells

The processes of ovarian cancer dissemination are characterized by altered local proteolysis, cellular proliferation, cell attachment, and invasion, suggesting that the urokinase-type plasminogen activator (uPA) and its specific inhibitor (plasminogen activator inhibitor type-1 (PAI-1)) could be involved in the pathogenesis of peritoneal dissemination. We showed previously that expression of uPA and PAI-1 in the human ovarian cancer cell line HRA can be down-regulated by exogenous bikunin (bik), a Kunitz-type protease inhibitor, via suppression of transforming growth factor-beta1 (TGF-beta1) up-regulation and that overexpression of the bik gene can specifically suppress the in vivo growth and peritoneal dissemination of HRA cells in an animal model. We hypothesize that the plasminogen activator system in mesothelial cells can be modulated by HRA cells. To test this hypothesis, we used complementary techniques in mesothelial cells to determine whether uPA and PAI-1 expression are altered by exposure to culture media conditioned by HRA cells. Here we show the following: 1) that expression of PAI-1, but not uPA, was markedly induced by culture media conditioned by wild-type HRA cells but not by bik transfected clones; 2) that by antibody neutralization the effect appeared to be mediated by HRA cell-derived TGF-beta1; 3) that exogenous TGF-beta1 specifically enhanced PAI-1 up-regulation at the mRNA and protein level in mesothelial cells in a time- and concentration-dependent manner, mainly through MAPK-dependent activation mechanism; and 4) that mesothelial cell-derived PAI-1 may promote tumor invasion possibly by enhancing cell-cell interaction. This represents a novel pathway by which tumor cells can regulate the plasminogen activator system-dependent cellular responses in mesothelial cells that may contribute to formation of peritoneal dissemination of ovarian cancer.