Matrix metalloproteinases: molecular aspects of their roles in tumour invasion and metastasis

Clinicopathological and biological significance of cripto overexpression in human colon cancer

AIM: To assess the clinicopathological and biological significance of cripto in human colorectal cancer.

METHODS: Real-time reverse-transcription polymerase chain reaction (PCR) was used to examine cripto mRNA levels in primary colon cancer and normal colon tissues as well as normal and metastatic lymph nodes from colon cancers. Human colon cancer LS-174T cells were transfected with cripto small interfering RNA (siRNA), and mRNA and protein levels were evaluated using real-time PCR and western blot analysis, respectively. The growth of cancer cells was evaluated using the MTT assay and colony formation in soft agar. Invasion was examined using a Transwell assay, and the expressions of matrix metalloproteinase (MMP)-7 and MMP-9 were determined using western blot assay.

RESULTS: Cripto was significantly overexpressed in primary colon cancer and metastatic lymph nodes. Silencing cripto gene expression with cripto siRNA resulted in a significant decrease in colony formation in soft agar in the colon cancer cell line LS-174T. Cripto siRNA treatment decreased the migration and invasion capabilities of the colon cancer cell line LS-174T in vitro. Furthermore, cripto siRNA treatment inhibited the expression of matrix MMP-7 and MMP-9.

CONCLUSION: The results provide evidence that cripto siRNA could be an effective approach for the inhibition of cancer cell invasion and migration and thus has potential for use in devising novel preventive and therapeutic strategies for colon cancer metastasis.

Invasion and metastasis of renal cell carcinoma

Renal cell carcinoma (RCC) represents over 80% of kidney cancer, and about 30% of the patients with RCC develop metastasis after the surgery. Invasion of basement membrane (BM) and extracellular matrix (ECM) is an essential event in tumor invasion and metastasis. Matrix metalloproteinases (MMPs), which digest the main components of BM and ECM, are expressed in RCC. Heparanase, which degrades heparan sulfate proteoglycans, is predominantly expressed in high-grade RCCs with a positive correlation with pathological tumor stage and poor prognosis. Bone metastasis is common among the patients with RCC, and increased osteoclastic activity was observed at metastatic sites. Receptor activator of nuclear factor κB ligand (RANKL), which plays an important role in osteoclastogenesis, is predominantly expressed in high-grade RCC and its expression level is associated with bone metastasis and prognosis. Epithelial-mesenchymal transition (EMT), a switch of epithelial cells to sarcomatoid phenotype, is considered to be critical step during metastasis, and Snail, a major regulator of EMT, is predominantly expressed in high-grade RCC, and high Snail expression is a worse prognostic factor. Accordingly, heparanase, RANKL and Snail may be targets for the development of anti-tumor therapies for RCCs.

Correlation between B7-H3 expression and matrix metalloproteinases 2 expression in pancreatic cancer

BACKGROUND

B7-H3 and matrix metalloproteinases 2 (MMP-2) are reported highly expressed in malignant tumor, we investigate the relationship between B7-H3 expression and MMP-2 on malignant behavior and prognosis predictable value in pancreatic cancer.

METHODS

We tested the expressions of B7-H3 and MMP-2 protein in 45 pancreatic surgical resected cancer samples; meanwhile, the clinicopathological data of enrolled patients were obtained for correlation analysis to obtain their relationship with pancreatic cancer progress.

RESULTS

The expression of B7-H3 was up-regulated with infiltrating depth, lymph node metastasis and TNM stage (P < 0.01). Positive expression rate of MMP-2 in pancreatic cancer tissues was 44.35%, whereas negative in normal pancreatic tissues. Multivariate analysis of Logistic regression showed B7-H3 and MMP-2 expressions were hazardous makers correlated with infiltrating depth (P < 0.05).

CONCLUSION

Our study showed combined detections of B7-H3 and MMP2 protein expression could identify patients at high risk in disease recurrence and prognosis more efficiently.

Role of microRNA-mediated MMP regulation in the treatment and diagnosis of malignant tumors

Matrix metalloproteinases (MMPs) play important roles in tumor cell proliferation and apoptosis and contribute to tumor growth, angiogenesis, migration, and invasion primarily via extracellular matrix (ECM) degradation and/or the activation of pre-pro-growth factors. Recently, there has been considerable interest in the posttranscriptional regulation of MMPs via microRNAs (miRs). In this review, we highlight the complicated interactive network comprised of different MMPs and their regulating microRNAs, as well as the ways in which these interactions influence cancer development, including tumor angiogenesis, growth, invasion, and metastasis. Based on the conclusive roles that microRNAs play in the regulation of MMPs during cancer progression, we discuss the potential use of microRNA-mediated MMP regulation in the diagnosis and treatment of tumors from the clinical perspective. In particular, microRNA-mediated MMP regulation may lead to the development of promising new MMP inhibitors that target MMPs more selectively, and this approach may also target multiple molecules in a network, leading to the efficient regulation of distinct biological processes relevant to malignant tumors. A thorough understanding of the mechanisms underlying microRNA-mediated MMP regulation during tumor progression will help to provide new insights into the diagnosis and treatment of malignant tumors.

β,β-carotene 15,15'-monooxygenase and its substrate β-carotene modulate migration and invasion in colorectal carcinoma cells

BACKGROUND

β,β-Carotene 15,15'-monooxygenase (BCMO1) converts β-carotene to retinaldehyde. Increased β-carotene consumption is linked to antitumor effects. Retinoic acid reduces the invasiveness in cancer, through inhibition of matrix metalloproteinases (MMPs). In our studies of a mouse model that develops intestinal tumors after low dietary folate, we found reduced BCMO1 expression in normal preneoplastic intestine of folate-deficient tumor-prone mice.

OBJECTIVE

Our goal was to determine whether BCMO1 expression could influence transformation potential in human colorectal carcinoma cells, by examining the effect of BCMO1 modulation on cellular migration and invasion, and on expression of MMPs.

DESIGN

LoVo colon carcinoma cells were transfected with BCMO1 small interfering RNA (siRNA) or scrambled siRNA. Migration and invasion were measured, and the expression of BCMO1, MMP7, and MMP28 was assessed by quantitative reverse-transcriptase polymerase chain reaction. These variables were also measured after treatment of cells with retinoic acid, 5-aza-2'-deoxycytidine, folate-depleted/high-methionine medium, and β-carotene.

RESULTS

Retinoic acid decreased the migration, invasion, and expression of MMP28 mRNA. Transfection of cells with BCMO1 siRNA inhibited BCMO1 expression, enhanced migration and invasion, and increased expression of MMP7 and MMP28. 5-Aza-2'-deoxycytidine decreased, whereas folate-depleted/high-methionine medium increased invasiveness. β-Carotene increased BCMO1 expression and reduced invasiveness with a decrease in expression of MMP7 and MMP28.

CONCLUSIONS

Inhibition of BCMO1 expression is associated with increased invasiveness of colon cancer cells and increased expression of MMP7 and MMP28. β-Carotene can upregulate BCMO1 and reverse these effects. These novel associations suggest a critical role for BCMO1 in cancer and provide a mechanism for the proposed antitumor effects of β-carotene.

Establishment of experimental glioma models at the intrinsic brainstem region of the rats

OBJECTIVES

As the treatment of human intrinsic brainstem gliomas remains challenging, experimental glioma models are needed.

METHODS

We developed a rat model of intrinsic brain stem glioma that uses a stereotactic frame to fix the head for the delivery of C6 glioma cells to target sites via a permanently implanted cannula. We inoculated the rat midbrain, pons or cerebral cortex with 5 x 10(4) cells suspended in 1 microl culture medium over the course of 2 minutes.

RESULTS

Three days post-implantation, tumor formation was visible in the periaqueductal gray matter in the midbrain and the tegmentum of the pons. On the tenth day, the tumor diameter exceeded over 2 mm; there was no tumor cell seeding into the cerebrospinal fluid space. The tumor manifested the histological features typical of glioblastoma; Ki-67 labeling index was 32%.

DISCUSSION

Because in our model the cannula is permanently implanted, additional inocula can be delivered. Here we detail our rat brainstem glioma model and discuss its usefulness for the investigation of these tumor in humans.

Effect of cyclopamine on expression of VEGF, MMP-2 and MMP-9 in gastric cancer cell line MKN45

AIM: To investigate the effect of cyclopamine on cell apoptosis and expression of vascular endothelial growth factor (VEGF), matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) in gastric cancer cell line MKN45.

METHODS: After MKN45 cells were treated with different concentrations of cyclopamine (7.5, 15, 30, 60, 90, 120 μmol/L) for different durations, cell proliferation was assessed by MTT assay, cell apoptosis and cell cycle progression were determined by flow cytometry, and expression of VEGF, MMP-2 and MMP-9 mRNAs was detected by RT-PCR.

RESULTS: Cyclopamine inhibited the growth of MKN45 cells in a time- and dose-dependent manner. The apoptosis rates of MKN45 cells treated with 30, 60, 90 μmol/L of cyclopamine for 24 h were significantly higher than that of non-treated cells (18.45% ± 0.57%, 39.77% ± 0.61%, 68.52% ± 0.89% vs 2.08% ± 0.49%, all P < 0.05). The percentage of cells in G₀/G₁ phase was increased while that in S phase was decreased in cyclopamine-treated cells, and cell cycle was arrested in G₀/G₁ phase. Treatment with cyclopamine for 24 h decreased the expression levels of VEGF, MMP-2 and MMP-9 mRNA in a dose-dependent manner (all P < 0.05).

CONCLUSION: Cyclopamine inhibits cell proliferation and induces apoptosis in gastric cancer cell line MKN45 via mechanisms possibly associated with down-regulating the expression of tumor invasion-related genes VEGF, MMP-2 and MMP-9.

Differential mechanisms of tumor progression in clones from a single heterogeneous human melanoma

We used vertical growth phase (VGP) human VMM5 melanoma cells to ask whether the tumor microenvironment could induce matrix metalloproteinase-1 (MMP-1) in vivo, and whether this induction correlated with metastasis. We isolated two clones from parental VMM5 cells: a low MMP-1 producing clone (C4) and high producing clone (C9). When these clones were injected orthotopically (intradermally) into nude mice, both were equally tumorigenic and produced equivalent and abundant amounts of MMP-1. However, the tumors from the C4 clones displayed different growth kinetics and distinct profiles of gene expression from the C9 population. The C4 tumors, which had low MMP-1 levels in vitro, appeared to rely on growth factors and cytokines in the microenvironment to increase MMP-1 expression in vivo, while MMP-1 levels remained constant in the C9 tumors. C9 cells, but not C4 cells, grew as spheres in culture and expressed higher levels of JARID 1B, a marker associated with melanoma initiating cells. We conclude that VMM5 melanoma cells exhibit striking intra-tumor heterogeneity, and that the tumorigenicity of these clones is driven by different molecular pathways. Our data suggest that there are multiple mechanisms for melanoma progression within a tumor, which may require different therapeutic strategies.

Effects of simvastatin and rosuvastatin on RAS protein, matrix metalloproteinases and NF-κB in lung cancer and in normal pulmonary tissues

OBJECTIVES

In this study, we have evaluated effects of 24-hour treatments with simvastatin or rosuvastatin on RAS protein, NF-κB and MMP expression in LC tissues obtained from 12 patients undergoing thoracic surgery.

MATERIALS AND METHODS

Normal and lung tumour tissues obtained from each sample were exposed to simvastatin (2.5-30 μm) or rosuvastatin (1.25-30 μm) and western blot analysis was then performed.

RESULTS

We documented increased expression of proteins, MMP-2, MMP-9 and NF-κB-p65 in LC tissues, with respect to normal tissues (P < 0.01). In the malignant tissues, simvastatin and rosuvastatin significantly (P < 0.01) and dose-dependently reduced RAS protein, MMP-2/9 and NF-κB-p65 expression.

CONCLUSIONS

In conclusion, our results suggest that simvastatin and rosuvastatin could play a role in LC treatment by modulation of RAS protein, MMP-2/9 and NF-κB-p65.

Matrix metalloproteinase-14 is a negative prognostic marker for patients with gastric cancer

BACKGROUND

Matrix metalloproteinase-14 (MMP-14) has been considered to play an important role in invasion and metastasis of human solid tumor.

AIM

The present study aimed to investigate the association of MMP-14 with overall survival in human gastric cancer.

METHODS

Gastric cancer and adjacent normal specimens were collected from 205 patients who had not received neoadjuvant chemotherapy. MMP-14 expression was investigated by immunohistochemistry assay and staining evaluation results were analyzed statistically in relation to overall survival of patients.

RESULTS

MMP-14 expression proved to be increased in gastric cancer compared with that in normal tissues. It was also proved that MMP-14 expression was associated with tumor invasion, metastasis, and TNM stage while no correlations were detected between MMP-14 expression and age, sex, differentiation status, or Lauren's classification. Moreover, patients with gastric cancer of MMP-14-positive expression tend to have worse overall survival compared with those with MMP-14 negative expression.

CONCLUSIONS

The present study confirmed the over-expression of MMP-14 in human gastric cancer and its association with tumor progression. It also provided the first evidence that MMP-14 expression in gastric cancer was an independent negative prognostic factor of patients.

S100A7 enhances invasion of human breast cancer MDA-MB-468 cells through activation of nuclear factor-κB signaling

Background

S100A7 signaling plays a critical role in the pathogenesis and progression of human breast cancers but the precise role and mechanism of S100A7 for tumor invasion remains unclear. in the present study, we investigated whether S100A7 overexpression could be mechanistically associated with the up-regulation of NF-κB, VEGF and MMP-9, resulting in the promotion of breast cancer cell invasion and growth, and vice versa.

Methods

pcDNA3.1-S100A7 cDNA plasmid was constructed and transfected into the MDA-MB-468 cells. 4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used to detect cell proliferation, Matrigel was used to detect cell mobility and invasion in vitro.The MMP-9 and VEGF expression and levels was detected by western blot and ELISA assay. NF-κB DNA binding activity was detected by Electrophoretic mobility shift assay.

Results

Up-regulation of S100A7 by stable S100A7 cDNA transfection increased cell invasion and proliferation, whereas downregulation of S100A7 by small interfering RNA in S100A7 cDNA-transfected MDA-MB-468 cells decreased cell invasion and proliferation. Consistent with these results, we found that the up-regulation of S100A7 increased NF-κB DNA-binding activity and MMP-9 and VEGF expression. Down-regulation of S100A7 in S100A7 cDNA -transfected decreased NF-κB DNA-binding activity and MMP-9 and VEGF expression.

Conclusions

Our data demonstrate that the S100A7 gene controls the proliferation and invasive potential of human MDA-MB-468 cells through regulation of NF-κB activity and its target genes, such as MMP-9 and VEGF expression. Down-regulation of S100A7 could be an effective approach for the down-regulation and inactivation of NF-κB and its target genes, such as MMP-9 and VEGF expression, resulting in the inhibition of invasion and growth.

The importance of the PI3K/AKT/MTOR pathway in the progression of ovarian cancer

Ovarian cancer is the fifth most common cause of death due to cancer in women despite being the tenth in incidence. Unfortunately, the five-year survival rate is only 45%, which has not improved much in the past 30 years. Even though the majority of women have successful initial therapy, the low rate of survival is due to the eventual recurrence and succumbing to their disease. With the recent release of the Cancer Genome Atlas for ovarian cancer, it was shown that the PI3K/AKT/mTOR pathway was one of the most frequently mutated or altered pathways in patients’ tumors. Researching how the PI3K/AKT/mTOR pathway affects the progression and tumorigensis of ovarian cancer will hopefully lead to new therapies that will increase survival for women. This review focuses on recent research on the PI3K/AKT/mTOR pathway and its role in the progression and tumorigensis of ovarian cancer.

Matrix metalloproteinase activity in early-stage lung cancer

BACKGROUND

The matrix metalloproteinases (MMPs)-2, -9 and -7 are thought to be associated with tumor invasion, metastasis, and angiogenesis. However, their possible roles in early-stage lung cancer are not clear. We measured the activity of MMP-2, -7 and -9 in early-stage lung cancer tissues.

MATERIAL AND METHODS

Normal lung tissues and cancer tissues were collected from 60 consecutive stage-I non-small cell lung cancer (NSCLC) patients. The activities of MMP-2 and MMP-9 were determined by gelatin zymography, and the activity of MMP-7 was determined by casein zymography. Furthermore, the ratio of the active form of MMP-2 in tumor tissue (T) compared with normal tissue (N) was determined, and the survival in the groups with different MMP-2 T:N ratio was compared.

RESULTS

The activity of both MMP-2 and MMP-9 was detected in all cancer and normal tissues. Interestingly, MMP-9 activity was significantly reduced, whereas MMP-2 activity was significantly increased, in cancer tissues compared to normal tissues. The survival rate of the MMP-2 T:N ratio > 2.5 group was 57.45%, which was significantly reduced compared with that of the T:N ratio ≤ 2.5 group (86.78%).

CONCLUSION

Our findings suggest that MMP-2, but not MMP-9 and MMP-7, may be implicated in early-stage tumor invasion, metastasis, and angiogenesis in NSCLC.

EMMPRIN is an independent negative prognostic factor for patients with astrocytic glioma

Extracellular matrix metalloproteinase inducer (EMMPRIN), also known as CD147, is a member of the immunoglobulin superfamily that is present on the surface of tumor cells and stimulates adjacent fibroblasts to produce matrix metalloproteinases (MMPs). It has been proved to be associated with tumor invasion and metastasis in various human malignancies. In our study, the protein expression level of EMMPRIN in 306 cases of astrocytic glioma is investigated by immunohistochemistry assay. Statistical analysis was utilized to evaluate the association of EMMPRIN with clinicopathological characteristics and prognosis of patients. It was proved that EMMPRIN protein expression was increased in glioma compared with that in normal brain tissue. Moreover, EMMPRIN immunohistochemical staining was correlated with WHO grade and Karnofsky performance score for strong positive EMMPRIN staining is more frequently detected in glioma of advanced grade or low KPS score. It is also demonstrated that EMMPRIN could be an independent negative prognostic factor in glioma for patients with glioma of strong EMMPRIN staining tend to have high risk of death. These results proved that EMMPRIN is associated with prognosis of glioma, which may also suggest the potential role of EMMPRIN in glioma management.

Diallyl trisulfide inhibits proliferation, invasion and angiogenesis of osteosarcoma cells by switching on suppressor microRNAs and inactivating of Notch-1 signaling

Notch signaling pathway plays critical roles in human cancers, including osteosarcoma, suggesting that the discovery of specific agents targeting Notch would be extremely valuable for osteosarcoma. Our previous studies have shown that diallyl trisulfide (DATS) inhibits proliferation of osteosarcoma cells by triggering cell cycle arrest and apoptosis in vitro. However, the underlying mechanism is still unclear. In this study, we found that DATS suppressed cell survival, wound-healing capacity, invasion and angiogenesis in osteosarcoma cells. These effects were associated with decreased expression of Notch-1 and its downstream genes, such as vascular endothelial growth factor and matrix metalloproteinases, as well as increased expression of a panel of tumor-suppressive microRNAs (miRNAs), including miR-34a, miR-143, miR-145 and miR-200b/c that are typically lost in osteosarcoma. We also found that reexpression of miR-34a and miR-200b by transfection led to reduced expression of Notch-1, resulting in the inhibition of osteosarcoma cell proliferation, invasion and angiogenesis. These results clearly suggest that DATS inhibited osteosarcoma growth and aggressiveness via a novel mechanism targeting a Notch-miRNA regulatory circuit. Our data provide the first evidence that the downregulation of Notch-1 and reexpression of miRNAs by DATS may be an effective approach for the treatment of osteosarcoma.

EMMPRIN/CD147 expression is associated with disease-free survival of patients with colorectal cancer

EMMPRIN/CD147 has been proved to be associated with tumor invasion and metastasis in various human malignancies. In the present study, we investigated the expression of CD147 and its association with disease-free survival of colorectal cancer patients. CD147 expression was investigated in 328 cases of colorectal cancer by immunohistochemistry assay. Statistical analysis was utilized to evaluate the association of CD147 expression with disease-free survival of colorectal cancer patients. CD147 expression was proved to be increased in colorectal cancer (P < 0.001) and related to tumor invasion (P < 0.001), metastasis (P < 0.001), and TNM stage (P < 0.001). Kaplan-Meier showed CD147 was associated with disease-free survival of patients with colorectal cancer for patients with higher CD147 expression tend to have shorter disease-free survival (P < 0.001). Multivariate analysis also proved CD147 to be an independent prognostic factor for disease-free survival of colorectal cancer patients (P < 0.05). These results suggested the potential role of CD147 in relapse of human colorectal cancer. It might be a novel molecular marker to predict relapse of patients with colorectal cancer.

Rapid and non-enzymatic in vitro retrieval of tumour cells from surgical specimens

The study of tumourigenesis commonly involves the use of established cell lines or single cell suspensions of primary tumours. Standard methods for the generation of short-term tumour cell cultures include the disintegration of tissue based on enzymatic and mechanical stress. Here, we describe a simple and rapid method for the preparation of single cells from primary carcinomas, which is independent of enzymatic treatment and feeder cells. Tumour biopsies are processed to 1 mm(3) cubes termed explants, which are cultured 1-3 days on agarose-coated well plates in specified medium. Through incisions generated in the explants, single cells are retrieved and collected from the culture supernatant and can be used for further analysis including in vitro and in vivo studies. Collected cells retain tumour-forming capacity in xenotransplantation assays, mimic the phenotype of the primary tumour, and facilitate the generation of cell lines.

The tumor suppressor gene ARHI (DIRAS3) inhibits ovarian cancer cell migration through multiple mechanisms

ARHI is an imprinted tumor suppressor gene that is downregulated in > 60% of ovarian cancers, associated with decreased progression-free survival. ARHI encodes a 26 kDa GTPase with homology to Ras. Re-expression of ARHI inhibits ovarian cancer growth, initiates autophagy and induces tumor dormancy. Recent studies have demonstrated that ARHI also plays a particularly important role in ovarian cancer cell migration. Re-expression of ARHI decreases motility of IL-6- and EGF-stimulated SKOv3 and Hey ovarian cancer cells, inhibiting both chemotaxis and haptotaxis. ARHI inhibits cell migration by binding and sequestering STAT3 in the cytoplasm, and preventing STAT3 translocation to the nucleus and localization in focal adhesion complexes. Re-expression of ARHI inhibits FAK (Y397) phosphorylation, disrupts focal adhesions and blocks FAK-mediated RhoA signaling, resulting in decreased levels of GTP-RhoA. Re-expression of ARHI disrupts formation of actin stress fibers in a FAK- and RhoA-dependent manner. Recent studies indicate that re-expression of ARHI inhibits expression of β-1 integrin which may also contribute to inhibition of migration, adhesion and invasion.

Increased co-expression of macrophage migration inhibitory factor and matrix metalloproteinase 9 is associated with tumor recurrence of meningioma

BACKGROUND AND OBJECTIVE

We detected the expression of MIF and matrix metalloproteinase 9 (MMP9) in meningiomas to determine whether they are valuable recurrence predictor for meningioma.

METHODS

67 cases of meningiomas, including 57 benign tumors (WHO grade I) and 10 non-benign tumors (WHO grade II and III), were collected, and expression of MIF and MMP9 in tissue microarray was evaluated immunohistochemically. The correlations between immunostainings and clinicopathological parameters, as well as the follow-up data of patients, were analyzed statistically.

RESULTS

Increased expressions of both MIF (58.2%, 39/67) and MMP9 (55.2%, 37/67) were significantly associated with microvessel density (MVD) of tumor, but only dual high-expression of MIF and MMP9 was in relation to tumor invasion (P=0.016) and tumor recurrence (P=0.001). Based on univariate analysis, histological grade, tumor invasion and co-expression of MIF and MMP9 were significant predictors for recurrence. However, only histological grade and co-expression of MIF and MMP9 in tumor were independent recurrence factors with a hazard ratio of 49.033 (P=0.002) and 37.766 (P=0.002) in multivariate analysis.

CONCLUSIONS

Together with histological grade, increased co-expression of MIF and MMP9 in tumor might be a valuable predictor for recurrence, especially for benign meningiomas.

Increased MMP-21 expression is associated with poor overall survival of patients with gastric cancer

Matrix metalloproteinase-21 (MMP-21) has been shown to enhance tumor invasion and metastasis ability in some solid tumors. In the present study, we investigated the expression of MMP-21 as well as its association with overall survival of gastric cancer patients. MMP-21 expression was investigated in 296 cases of gastric cancer by immunohistochemistry assay. Statistical analysis was utilized to evaluate the association of MMP-21 expression with overall survival of patients. MMP-21 expression was proved to be increased in gastric cancer compared with that in normal tissues (P < 0.05). It was also proved MMP-21 expression was associated with tumor invasion, metastasis and TNM stage (P < 0.001). MMP-21 expression was showed to be associated with overall survival of gastric cancer patients for patients with tumor of higher MMP-21 expression tend to have worse overall survival (P < 0.001). Multivariate analysis proved MMP-21 to be an independent prognostic factor for overall survival of gastric cancer patients (P < 0.001). These results suggested the potential role of MMP-21 in progression of human gastric cancer. It might also be a novel molecular marker to predict overall survival of patients with gastric cancer.

Matrix metalloproteinase-12 is associated with overall survival in Chinese patients with gastric cancer

BACKGROUND AND OBJECTIVES

Matrix metalloproteinase-12 (MMP-12) plays an important role in invasion and metastasis of human solid tumor cells. This study aimed to investigate the association of MMP-12 with overall survival in human gastric cancer.

METHODS

Gastric cancer and adjacent normal tissue specimens were collected from 165 patients who had not received neoadjuvant chemotherapy. MMP-12 expression was determined by immunohistochemical staining, and the results were analyzed statistically in relation to the overall survival of the patients.

RESULTS

MMP-12 expression was increased in gastric cancer compared with that observed in normal tissues. Increased MMP-12 expression was associated with tumor invasion, lymph node metastasis, distant metastasis, and TNM stage. No correlations were detected between MMP-12 expression and age, sex, differentiation status, tumor site, or Lauren classification. Moreover, patients with MMP-12 positive gastric cancer tended to have worse overall survival compared with those patients without MMP-12 expression.

CONCLUSIONS

The study results showed that increased expression of MMP-12 was associated with tumor progression in gastric cancer. It also provided the first evidence for MMP-12 expression in gastric cancer as an independent prognostic factor.

Olfactomedin 4 suppresses tumor growth and metastasis of mouse melanoma cells through downregulation of integrin and MMP genes

Olfactomedin 4 (OLFM4) is highly expressed in gastrointestinal cancers and has an anti-apoptotic function. The roles of OLFM4 in tumor growth and metastasis and how it functions in these processes remain elusive. We investigated the function of OLFM4 in tumor growth and metastasis using B16F10 mouse melanoma cells as an experimental system. Our results showed that OLFM4 had no positive effect on cell viability or cell cycle progression in B16F10 cells. However, it significantly suppressed the tumorigenicity of B16F10 cells, i.e., intradermal primary tumor growth and lung metastasis. OLFM4 also suppressed the migration and invasion of B16F10 cells in vitro. For further insight into the mechanisms underlying OLFM4-mediated suppression of tumor progression, we examined the effect of OLFM4 on the expression of integrin and matrix metalloproteinase (MMP), both of which are involved in tumor progression. Overexpression of OLFM4 clearly reduced the expression levels of integrin α1, integrin α4, integrin α5, integrin α6, and MMP9. Moreover, forced expression of MMP9 attenuated the inhibitory activity of OLFM4 on migration and invasiveness. Our findings provide the experimental evidence that OLFM4 may function as a tumor suppressor and an anti-metastatic gene during tumor progression.

Immunohistochemical expression of MMP-9 and VEGF in squamous cell carcinoma of the tongue

Squamous cell carcinomas (SCCs) account for approximately 95% of all oral malignant neoplasms and for about 38% of all malignant head and neck tumors, especially affecting the tongue and lips. The aim of this study was to evaluate the immunohistochemical expression of MMP-9 and VEGF in oral SCC according to the occurrence of metastasis. Eighteen cases of tongue SCC without metastases and 17 cases of tongue SCC with metastases were subjected to immunohistochemical methods. High immunohistochemical expression of MMP-9 and VEGF by neoplastic cells and stroma was observed in tongue SCCs at the invasion front. Metastatic tumors tended to express higher levels of MMP-9 and VEGF than non-metastatic tumors, but the difference was not significant (P > 0.05). Spearman's correlation test showed no significant correlation between VEGF-immunopositive vessels and metastasis (P > 0.05). The present results demonstrate the importance of the expression of MMP-9 and VEGF for the development of SCC of the tongue. However, no significant association was observed between the overexpression of MMP-9 or VEGF and the presence of metastases.

Knockdown of MMP-7 inhibits cell proliferation and enhances sensitivity to 5-Fluorouracil and X-ray irradiation in colon cancer cells

The role of matrix metalloproteinase-7 (MMP-7) in the pathogenesis of colon cancer is not understood thoroughly. Previous studies from our group have shown that the expression levels of MMP-7 were highly elevated in colorectal cancer patient specimens and were correlated with Dukes Staging, histological differentiation grade and CEA level. The goal of this study was to investigate the cellular impact of MMP-7 in colon cancer. In this study, we used the SW480 colon cancer cell lines of MMP-7 knockdown by lentivirus-mediated RNA interference as a model system to investigate the impact of MMP-7 on cell proliferation and sensitivity to 5-Fluorouracil (5-FU) and X-ray irradiation (IR). Cell proliferation and sensitivity to 5-FU and IR were measured by MTT assay and colony formation assay. Cell cycle was evaluated by flow cytometry. We showed that the down regulation of MMP-7 inhibits colon cancer cell proliferation and sensitizes tumour cells to 5-FU and IR (P < 0.05). Decreased MMP-7 expression in SW480 cells by RNA interference triggered cell cycle arrest at G1 phase (P < 0.05). Down regulation of MMP-7 may inhibit the cell proliferation of colon cancer cells and increase tumour cells sensitivity to radiotherapy and chemotherapy. RNAi-mediated silencing of MMP-7 may represent a powerful therapeutic approach for controlling human colorectal cancer growth.

Piceatannol inhibits MMP-9-dependent invasion of tumor necrosis factor-α-stimulated DU145 cells by suppressing the Akt-mediated nuclear factor-κB pathway

Piceatannol has potent anti-inflammatory, immunomodulatory, anticancer and antiproliferative effects. However, little is known about the mechanism by which piceatannol inhibits invasion and metastasis. The aim of the current study was to investigate the effects of piceatannol on the expression of matrix metalloproteinase-9 (MMP-9) in DU145 human prostate cancer cells. The results revealed that MMP-9 activity was significantly increased in response to tumor necrosis factor-α (TNF-α). However, treatment with piceatannol reversed TNF-α- and MMP-9-induced gelatin zymography and its gene expression. In addition, a Matrigel invasion assay determined that piceatannol reduces the TNF-α-induced invasion of DU145 cells. Nuclear factor-κ B (NF-κB) is a significant transcription factor that regulates numerous genes involved in tumor cell invasion and metastasis. Therefore, whether piceatannol acts on NF-κB to regulate MMP-9 gene expression was analyzed. The results revealed that piceatannol attenuates MMP-9 gene expression via the suppression of NF-κB activity. Using a specific NF-κB inhibitor, pyrrolidine dithiocarbamate, it was confirmed that TNF-α-induced MMP-9 gene expression is primarily regulated by NF-κB activation. Piceatannol inhibited NF-κB activity by suppressing nuclear translocation of the NF-κB p65 and p50 subunits. Furthermore, TNF-α-induced Akt phosphorylation was significantly downregulated in the presence of piceatannol. The Akt inhibitor LY294002 caused a significant decrease in TNF-α-induced NF-κB activity and MMP-9 gene expression. Overall, these data suggest that piceatannol inhibits TNF-α-induced invasion by suppression of MMP-9 activation via the Akt-mediated NF-κB pathway in DU145 prostate cancer cells.

Thymic alterations induced by Plasmodium berghei: expression of matrix metalloproteinases and their tissue inhibitors

The thymus plays a crucial role in the generation of T-cells, and so our laboratory has been interested in the study of the intrathymic events that occur during infection diseases and may cause disruption in its functions. Previously, we showed that thymus from experimentally Plasmodium berghei-infected mice present histological alterations with high levels of apoptosis, changes in cell migration-related molecules, and premature egress of immature thymocytes to periphery. In addition, parasites were found inside the thymus. In this work we investigated alterations in the expression pattern and activity of matrix metalloproteinases MMP-2 and -9, and their tissue inhibitors, TIMP-1 and TIMP-2. Our results show enhanced expression and widespread distribution of these molecules in thymus from infected animals. Also, the presence of active MMP-2 was detected. These data are suggestive of MMPs and TIMPs importance in the earlier observed changes in the extracellular matrix during thymic alterations after plasmodium infection.

Overexpression of FoxM1 is associated with tumor progression in patients with clear cell renal cell carcinoma

Background

Fork head box M1 (FoxM1) is a proliferation-associated transcription factor essential for cell cycle progression. Numerous studies have documented that FoxM1 has multiple functions in tumorigenesis and its elevated levels are frequently associated with cancer progression. The present study was conducted to investigate the expression of FoxM1 and its prognostic significance in clear cell renal cell carcinoma (ccRCC). Meanwhile, the function of FoxM1 in human ccRCC was further investigated in cell culture models.

Methods

Real-time quantitative PCR, western blot and immunohistochemistry were used to explore FoxM1 expression in ccRCC cell lines and primary ccRCC clinical specimens. FoxM1 expression was knocked down by small interfering RNA (siRNA) in Caki-1 and 786-O cells; proliferation, colony formation, cell cycle, migration, invasion, and angiogenesis were assayed.

Results

FoxM1 expression was up-regulated in the majority of the ccRCC clinical tissue specimens at both mRNA and protein levels. Clinic pathological analysis showed that FoxM1 expression was significantly correlated with primary tumor stage (P <0.001), lymph node metastasis (P = 0.01), distant metastasis (P = 0.01), TNM stage (P < 0.001) and histological grade (P = 0.003). The Kaplan–Meier survival curves revealed that high FoxM1 expression was associated with poor prognosis in ccRCC patients (P < 0.001). FoxM1 expression was an independent prognostic marker of overall ccRCC patient survival in a multivariate analysis (P = 0.008). Experimentally, we found that down-regulation of FoxM1 inhibited cell proliferation and induced cell cycle arrest with reduced expression of cyclin B1, cyclin D1, and Cdk2, and increased expression of p21 and p27. Also, down-regulation of FoxM1 reduced expression and activity of matrix metalloproteinase-2 (MMP-2), MMP-9 and vascular endothelial growth factor (VEGF), resulting in the inhibition of migration, invasion, and angiogenesis.

Conclusions

These results suggest that FoxM1 expression is likely to play important roles in ccRCC development and progression, and that FoxM1 is a prognostic biomarker and a promising therapeutic target for ccRCC.

MicroRNAs and metastasis-related gene expression in Egyptian breast cancer patients

AIM AND BACKGROUND

MicroRNAs (miRNAs) are a class of naturally occurring small noncoding RNAs that regulate gene expression, cell growth, differentiation and apoptosis by targeting mRNAs for translational repression or cleavage. The present study was conducted to study miRNAs in Egyptian breast cancer (BC) and their relation to metastasis, tumor invasion and apoptosis in addition to their association with the ER and PR statuses.

METHODS

Real Time RT-PCR was performed to identify the miRNA expression level of eight miRNAs and eight metastatic-related genes in 40 breast cancer samples and their adjacent non-neoplastic tissues. The expression levels of each miRNA relative to U6 RNA were determined. Also, miRNA expression profiles of the BC and their corresponding ANT were evaluated.

RESULTS

The BC patients showed an up-regulation in miRNAs (mir-155, mir-10, mir-21 and mir-373) with an upregulation in MMP2, MMp9 and VEGF genes. We found down regulation in mir-17p, mir-126, mir-335, mir-30b and also TIMP3, TMP1 and PDCD4 genes in the cancer tissue compared to the adjacent non-neoplastic tissues. Mir -10b, mir -21, mir-155 and mir373 and the metastatic genes MMP2, MMP9 and VEGF were significantly associated with an increase in tumor size (P<0.05). No significant difference was observed between any of the studied miRNAs regarding lymph node metastasis. Mir-21 was significantly over-expressed in ER-/PR- cases.

CONCLUSION

Specific miRNAs (mir-10, mir-21, mir-155, mir-373, mir-30b, mir-126, mir-17p, mir-335) are associated with tumor metastasis and other clinical characteristics for BC, facilitating identification of individuals who are at risk.

Matrix metalloproteinase-9 expression is increased in astrocytic glioma and associated with prognosis of patients

OBJECTIVE

Glioma is the most common type of primary central nervous system tumor. This study was aimed at investigating the expression of matrix metalloproteinase-9 in astrocytic glioma samples and its association with clinicopathological characteristics as well as survival of patients.

METHODS

Astrocytic glioma samples from 272 patients who had not received chemotherapy or radiotherapy were collected, in which matrix metalloproteinase-9 expression was assessed by immunochemistry assays. The association of staining evaluation results with clinicopathological characteristics was analyzed by appropriate statistical analysis. Kaplan-Meier analysis and Cox proportional hazards regression models were used to investigate the association between matrix metalloproteinase-9 expression and survival of patients.

RESULTS

Results showed that matrix metalloproteinase-9 expression is increased in astrocytic glioma and associated with tumor progression as its expression increased from Grade II to Grade IV glioma (P<0.001). Kaplan-Meier analysis showed that patients with glioma with higher matrix metalloproteinase-9 expression tend to have shorter overall survival time (P<0.001). In multivariate analysis, matrix metalloproteinase-9 expression was proved to be an independent prognostic factor for patients with astrocytic glioma (P<0.001).

CONCLUSIONS

This study confirmed the overexpression of matrix metalloproteinase-9 and its association with tumor progression in astrocytic glioma. It also provided the first evidence that matrix metalloproteinase-9 expression in glioma was an independent prognostic factor of patients, which might be a potential diagnostic and therapeutic target of astrocytic glioma.

Applications of cell-penetrating peptides for tumor targeting and future cancer therapies

Cell-penetrating peptides provide a highly promising strategy for intracellular drug delivery. One relevant clinical application of cell-penetrating peptides is cancer therapeutics. Peptide based delivery could increase the uptake of drugs in tumor cells and thereby increase the efficacy of the treatment, either of conventional small molecular drugs or oligonucleotide based therapeutics. This review is focused on the cancer applications of cell penetrating peptides as delivery systems; different aspects of drug loading, cargoes and delivery are discussed together with methods for targeted delivery, activatable cell-penetrating peptides and transducible agents coupled to cell-penetrating peptides.

Clinicopathological significance and prognostic value of MMP-13 expression in colorectal cancer

The purpose of this study was to evaluate the association of matrix metalloproteinase-13 (MMP-13) expression with clinicopathological features and prognosis in colorectal cancer (CRC) patients. CRC tissues and distal normal mucosa tissues of 158 CRC patients were detected by immunohistochemistry. The correlations between MMP-13 expression, the patients' clinicopathological features, and overall survival rate were analyzed. It was found that positive expression rate of MMP-13 in distal normal mucosa tissues was significantly lower than that in CRC tissues (36.7% vs 60.8%, p < 0.001). Poor histological differentiation, advanced clinical stage and lymph node metastasis were significantly correlated with the MMP-13 expression in CRC. The overall survival rate of the MMP-13-negative group was significantly higher than the positive group (Log-rank test = 12.452, p < 0.001). Collectively, we found that MMP-13 was correlated with progression and metastasis of CRC and could be used as a prognostic marker in CRC.

Cellular apoptosis susceptibility (chromosome segregation 1-like, CSE1L) gene is a key regulator of apoptosis, migration and invasion in colorectal cancer

Cellular apoptosis susceptibility (chromosome segregation 1-like, CSE1L) gene maps to chromosomal region 20q13.13, a region frequently amplified in solid tumours. In this study, we investigated the roles played by CSE1L in colorectal cancer by examining CSE1L expression and clinico-pathological parameters in colorectal cancer and investigating the effect of CSE1L on the viability, adhesion and migration of colorectal cancer cells. RT-PCR showed that CSE1L mRNA was over-expressed in colorectal cancer. CSE1L depletion by knock-down with CSE1L-specific siRNA significantly reduced viability in HCT116 cells (p = 0.004) and SW480 cells (p = 0.003) whilst significantly increasing the proportion of apoptotic HCT116 cells (p < 0.001) and SW480 cells (p < 0.001). Furthermore, CSE1L depletion significantly reduced the adhesive capacity of HCT116 (p = 0.003) and SW480 cells (p = 0.004). Analysis by qRT-PCR following CSE1L siRNA treatment of HCT116 and SW480 cells showed significant modulation of key apoptotic (p53, p73 and BAK) and adhesive (E-cadherin, Ep-CAM and ICAM-1) molecules. Immunohistochemistry of a colorectal cancer tissue microarray showed that CSE1L had a significantly increased level in colorectal cancer compared to normal colorectal epithelium (p < 0.001). There were significant decreases in both nuclear (p = 0.006) and cytoplasmic (p = 0.003) staining of CSE1L in tumours with lymph node metastasis (stage 3 tumours) compared with lymph node-negative tumours (stage 1 and 2 tumours). In lymph node-negative patients, poor survival was associated with increased CSE1L cytoplasmic expression (p = 0.042). These results indicate that CSE1L is associated with viability and apoptosis, cellular adhesion and invasion, thus implicating CSE1L in the progression of colorectal cancer.

Gelatinases A and B expression in human colorectal cancer in upper Egypt: a clinicopathological study

AIM

Prognosis of colorectal carcinoma depends on many factors, such as age and sex of patient; location; multiplicity; local extent and size of tumor, bowel obstruction, or perforation; as well as tumor microscopic type and grade; vascular and perineural invasion; and nodal and distant metastasis. The matrix metalloproteinases (MMPs) are a family of proteolytic enzymes strongly implicated in tumor invasion and metastasis, hence in tumor prognosis. The purpose of this study was to assess the role of MMP-2 and MMP-9 expression in colorectal tumorigenesis, invasion, and metastasis, hence their prognostic values.

METHOD

Immunohistochemical analysis of MMP-2 and MMP-9 in colorectal cancer cells, an immunohistochemical score based on the intensity of immunoreactivity and proportion of immunoreactive cells that established for each MMP, and correlation of this expression with the established prognostic factors.

RESULTS

MMP-2 was expressed in 81.8% (strong expression in 40%) of cases, and MMP-9 was expressed in 72% (strong expression in 35%) of cases.

CONCLUSIONS

MMP-2 and MMP-9 are widely expressed in colorectal carcinoma, suggesting significant diagnostic and prognostic values in these tumors. Increased levels of MMP-2 and MMP-9 protein expression in colorectal carcinoma tissues as compared to normal tissues suggest their association with colorectal tumor invasion and metastasis and that they could be targets for intervention and therapy in colorectal carcinoma.

Matrix metalloproteinase-2 promotes αvβ3 integrin-mediated adhesion and migration of human melanoma cells by cleaving fibronectin

BACKGROUND

Matrix metalloproteinase-2 (MMP-2) is a key regulator in the migration of tumor cells. αvβ3 integrin has been reported to play a critical role in cell adhesion and regulate the migration of tumor cells by promoting MMP-2 activation. However, little is known about the effects of MMP-2 on αvβ3 integrin activity and αvβ3 integrin-mediated adhesion and migration of tumor cells.

METHODOLOGY/PRINCIPAL FINDINGS

Human melanoma cells were seeded using an agarose drop model and/or subjected to in vitro analysis using immunofluorescence, adhesion, migration and invasion assays to investigate the relationship between active MMP-2 and αvβ3 integrin during the adhesion and migration of the tumor cells. We found that MMP-2 was localized at the leading edge of spreading cells before αvβ3 integrin. αvβ3 integrin-mediated adhesion and migration of the tumor cells were inhibited by a MMP-2 inhibitor. MMP-2 cleaved fibronectin into small fragments, which promoted the adhesion and migration of the tumor cells.

CONCLUSION/SIGNIFICANCE

MMP-2 cleaves fibronectin into small fragments to enhance the adhesion and migration of human melanoma cells mediated by αvβ3 integrin. These results indicate that MMP-2 may guide the direction of the tumor cell migration.

Serum MMPs 7-9 and their inhibitors during glucocorticoid and anti-TNF-α therapy in pediatric inflammatory bowel disease

OBJECTIVES

In inflammatory bowel diseases (IBD), matrix metalloproteinases (MMPs) participate in intestinal tissue damage and regenerative processes. MMP activity is inhibited by tissue inhibitors of MMPs (TIMPs) and plasma inhibitor, α₂-macroglobulin (α2M). We evaluated serum MMPs, their inhibitors and markers of neutrophil activity, myeloperoxidase (MPO) and human neutrophil elastase (HNE), during glucocorticoid (GC) and anti-TNF-α therapies in pediatric IBD, in aim to find new tools for assessment of therapeutic response.

METHODS

Serum samples were collected before and within a month after the start of therapy with oral GC (n = 19) or anti-TNF-α agent (n = 16), and from 32 pediatric control patients. Serum levels of MMP-7, MMP-9, TIMP-1, TIMP-2, α2M, MPO, and HNE were analyzed with enzyme-linked immunoabsorbent assays (ELISA) and MMP-8 by immunofluorometric assay (IFMA). Disease activity was monitored with erythrocyte sedimentation rate (ESR), CRP, fecal calprotectin (FC), and physician's global assessment of clinical disease activity (PGA).

RESULTS

In IBD, pretreatment serum MMP-7, MMP-8, MMP-9, α2M, MPO, and HNE were elevated compared with controls. During GC therapy, MMP-7, TIMP-1, and MMP-7/TIMP-2 decreased (all p < 0.05). During anti-TNF-α therapy, MMP-7 decreased (p = 0.063), but remained higher than that after GC therapy (p < 0.05). α2M (p < 0.05) and HNE (p < 0.05) increased, the former higher than that in GC-treated patients. The levels of MMPs and their inhibitors did not markedly associate with inflammatory markers in blood or feces.

CONCLUSIONS

In pediatric IBD, serum MMP-7 mirrors disease activity, and together with TIMP-1, reflects GC therapy response. α₂-Macroglobulin expression parallels the anti-TNF-α response.

High-density lipoprotein of patients with type 2 diabetes mellitus elevates the capability of promoting migration and invasion of breast cancer cells

Epidemiological studies suggested complicated associations between type 2 diabetes mellitus and breast cancer. There is a significant inverse association between high-density lipoprotein (HDL) and the risk and mortality of breast cancer. However, HDL could be modified in various ways in diabetes patients, and this may lead to the altered effects on many different types of cells. In our study, we found that glycation and oxidation levels are significantly higher in HDL from type 2 diabetes mellitus patients compared to that from healthy subjects. Diabetic HDL dramatically had a stronger capability to promote cell proliferation, migration and invasion of breast cancer (as examined both on hormone-independent cells and on hormone-dependent cells). In addition, glycated and oxidized HDL, which were produced in vitro, acted in similar way as diabetic HDL. Diabetic HDL, glycated HDL and oxidized HDL also induced higher synthesis and secretion of VEGF-C, MMP-2 and MMP-9 from malondialdehyde (MDA)-MB-231 cells. It was indicated that diabetic, glycated and oxidized HDL promote MDA-MB-231 cell migration and invasion through ERK and p38 MAPK pathways, and Akt pathway plays an important role as well in MDA-MB-231 cell invasion. The Akt, ERK and p38 MAPK pathways are also involved in VEGF-C and MMP-9 secretion induced by diabetic, glycated and oxidized HDL. Our study demonstrated that glycation and oxidation of HDL in diabetic patients could lead to abnormal actions on MDA-MB-231 cell proliferation, migration and invasion, thereby promoting the progression of breast cancer. This will largely draw the attention of HDL-based treatments in diabetic patients especially those with breast cancer.

Paracrine interactions between primary human macrophages and human fibroblasts enhance murine mammary gland humanization in vivo

INTRODUCTION

Macrophages comprise an essential component of the mammary microenvironment necessary for normal gland development. However, there is no viable in vivo model to study their role in normal human breast function. We hypothesized that adding primary human macrophages to the murine mammary gland would enhance and provide a novel approach to examine immune-stromal cell interactions during the humanization process.

METHODS

Primary human macrophages, in the presence or absence of ectopic estrogen stimulation, were used to humanize mouse mammary glands. Mechanisms of enhanced humanization were identified by cytokine/chemokine ELISAs, zymography, western analysis, invasion and proliferation assays; results were confirmed with immunohistological analysis.

RESULTS

The combined treatment of macrophages and estrogen stimulation significantly enhanced the percentage of the total gland humanized and the engraftment/outgrowth success rate. Timecourse analysis revealed the disappearance of the human macrophages by two weeks post-injection, suggesting that the improved overall growth and invasiveness of the fibroblasts provided a larger stromal bed for epithelial cell proliferation and structure formation. Confirming their promotion of fibroblasts humanization, estrogen-stimulated macrophages significantly enhanced fibroblast proliferation and invasion in vitro, as well as significantly increased proliferating cell nuclear antigen (PCNA) positive cells in humanized glands. Cytokine/chemokine ELISAs, zymography and western analyses identified TNFα and MMP9 as potential mechanisms by which estrogen-stimulated macrophages enhanced humanization. Specific inhibitors to TNFα and MMP9 validated the effects of these molecules on fibroblast behavior in vitro, as well as by immunohistochemical analysis of humanized glands for human-specific MMP9 expression. Lastly, glands humanized with macrophages had enhanced engraftment and tumor growth compared to glands humanized with fibroblasts alone.

CONCLUSIONS

Herein, we demonstrate intricate immune and stromal cell paracrine interactions in a humanized in vivo model system. We confirmed our in vivo results with in vitro analyses, highlighting the value of this model to interchangeably substantiate in vitro and in vivo results. It is critical to understand the signaling networks that drive paracrine cell interactions, for tumor cells exploit these signaling mechanisms to support their growth and invasive properties. This report presents a dynamic in vivo model to study primary human immune/fibroblast/epithelial interactions and to advance our knowledge of the stromal-derived signals that promote tumorigenesis.

Downregulation of the Notch signaling pathway inhibits hepatocellular carcinoma cell invasion by inactivation of matrix metalloproteinase-2 and -9 and vascular endothelial growth factor

Hepatocellular carcinoma (HCC) is one of the most common malignancies. The main cause of death in HCC patients is tumor progression with invasion and metastasis. However, the underlying mechanisms of HCC invasion and metastasis are still not fully understood. Some studies show that the Notch signaling pathway may participate in tumor invasion and metastasis. However, the mechanisms by which the Notch signaling pathway mediates tumor cell invasion, especially in hepatocellular carcinoma, are not yet known. In the current study, we investigated the anti-invasion effect of the downregulation of the Notch signaling pathway by DAPT in HCC cells. The Notch signaling pathway inhibitor could suppress invasion of HCC cells via the extracellular signal-regulated kinases 1 and 2 (ERK1/2) signaling pathways, resulting in the downregulation of matrix metalloproteinase-2 and -9 (MMP-2 and -9) and vascular endothelial growth factor (VEGF). These observations suggested that inhibition of the Notch signaling pathway by DAPT would be useful for devising novel preventive and therapeutic strategies targeting invasion of HCC.