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

Targeting vascular disrupting agent-treated tumor microenvironment with tissue-penetrating nanotherapy

Cancer treatment with vascular disrupting agents (VDAs) causes rapid and extensive necrosis in solid tumors. However, these agents fall short in eliminating all malignant cells, ultimately leading to tumor regrowth. Here, we investigated whether the molecular changes in the tumor microenvironment induced by VDA treatment sensitize the tumors for secondary nanotherapy enhanced by clinical-stage tumor penetrating peptide iRGD. Treatment of peritoneal carcinomatosis (PC) and breast cancer mice with VDA combretastatin A-4 phosphate (CA4P) resulted in upregulation of the iRGD receptors αv-integrins and NRP-1, particularly in the peripheral tumor tissue. In PC mice treated with CA4P, coadministration of iRGD resulted in an approximately threefold increase in tumor accumulation and a more homogenous distribution of intraperitoneally administered nanoparticles. Notably, treatment with a combination of CA4P, iRGD, and polymersomes loaded with a novel anthracycline Utorubicin (UTO-PS) resulted in a significant decrease in the overall tumor burden in PC-bearing mice, while avoiding overt toxicities. Our results indicate that VDA-treated tumors can be targeted therapeutically using iRGD-potentiated nanotherapy and warrant further studies on the sequential targeting of VDA-induced molecular signatures.

Cancer invasion and metastasis: Insights from murine pubertal mammary gland morphogenesis

Cancer invasion and metastasis accounts for the majority of cancer related mortality. A better understanding of the players that drive the aberrant invasion and migration of tumors cells will provide critical targets to inhibit metastasis. Postnatal pubertal mammary gland morphogenesis is characterized by highly proliferative, invasive, and migratory normal epithelial cells. Identifying the molecular regulators of pubertal gland development is a promising strategy since tumorigenesis and metastasis is postulated to be a consequence of aberrant reactivation of developmental stages. In this review, we summarize the pubertal morphogenesis regulators that are involved in cancer metastasis and revisit pubertal mammary gland transcriptome profiling to uncover both known and unknown metastasis genes. Our updated list of pubertal morphogenesis regulators shows that most are implicated in invasion and metastasis. This review highlights molecular linkages between development and metastasis and provides a guide for exploring novel metastatic drivers.

IL35 predicts prognosis in gastric cancer and is associated with angiogenesis by altering TIMP1, PAI1 and IGFBP1

Tumor angiogenesis is required for tumor growth and metastasis. Interleukin‐35 (IL35), a member of the IL12 family, is a dimer composed of IL12A and EBV‐induced gene 3（EBI3）. Elevated plasma IL35 levels have been reported to be associated with the occurrence and development of tumors. However, the role of IL35 in the angiogenesis of gastric cancer (GC) is still unclear. Here, we report that expression of IL35 is correlated with higher microvessel density, distant metastasis and poor prognosis in GC. Moreover, in vitro tube formation assays were performed to show that IL35 may contribute to the tube formation abilities of human umbilical vein endothelial cells. IL12A was observed to be the dominant subunit in promotion of tube formation. IL12A also inhibited expression of tissue inhibitor of metalloproteinase 1 and enhanced expression of plasminogen activator inhibitor 1 and insulin‐like growth factor‐binding protein 1 in a GC cell line. In conclusion, our data suggest that IL35 is involved in angiogenesis and is associated with poor prognosis for GC.

The biological properties of different Epstein-Barr virus strains explain their association with various types of cancers

The Epstein-Barr virus (EBV) is etiologically associated with the development of multiple types of tumors, but it is unclear whether this diversity is due to infection with different EBV strains. We report a comparative characterization of SNU719, GP202, and YCCEL1, three EBV strains that were isolated from gastric carcinomas, M81, a virus isolated in a nasopharyngeal carcinoma and several well-characterized laboratory type A strains. We found that B95-8, Akata and GP202 induced cell growth more efficiently than YCCEL1, SNU719 and M81 and this correlated positively with the expression levels of the viral BHRF1 miRNAs. In infected B cells, all strains except Akata and B95-8 induced lytic replication, a risk factor for carcinoma development, although less efficiently than M81. The panel of viruses induced tumors in immunocompromised mice with variable speed and efficacy that did not strictly mirror their in vitro characteristics, suggesting that additional parameters play an important role. We found that YCCEL1 and M81 infected primary epithelial cells, gastric carcinoma cells and gastric spheroids more efficiently than Akata or B95-8. Reciprocally, Akata and B95-8 had a stronger tropism for B cells than YCCEL1 or M81. These data suggest that different EBV strains will induce the development of lymphoid tumors with variable efficacy in immunocompromised patients and that there is a parallel between the cell tropism of the viral strains and the lineage of the tumors they induce. Thus, EBV strains can be endowed with properties that will influence their transforming abilities and the type of tumor they induce.

Mechanisms of peritoneal dissemination in gastric cancer

Peritoneal dissemination is the most frequent metastatic pattern of gastric cancer, but the mechanisms underlying peritoneal dissemination are yet to be elucidated. Paget's 'seed and soil' hypothesis is recognized as the fundamental theory of metastasis. The 'seeding' theory proposes that the formation of peritoneal dissemination is a multistep process, including detachment from the primary tumour, transmigration and attachment to the distant peritoneum, invasion into subperitoneal tissue and proliferation with blood vascular neogenesis. In the present review, the progress of each step is discussed. Milky spots, as a lymphatic apparatus, are indicative of lymphatic orifices on the surface of the peritoneum. These stomata are open gates for peritoneal-free cancer cells to migrate into the submesothelial space. Therefore, milky spots provide suitable 'soil' for cancer cells to implant. Other theories have also been proposed to clarify the peritoneal dissemination process, including the transvessel metastasis theory, which suggests that the peritoneal metastasis of gastric cancer develops via a vascular network mediated by hypoxia inducible factor-1α.

Broad targeting of angiogenesis for cancer prevention and therapy

Deregulation of angiogenesis--the growth of new blood vessels from an existing vasculature--is a main driving force in many severe human diseases including cancer. As such, tumor angiogenesis is important for delivering oxygen and nutrients to growing tumors, and therefore considered an essential pathologic feature of cancer, while also playing a key role in enabling other aspects of tumor pathology such as metabolic deregulation and tumor dissemination/metastasis. Recently, inhibition of tumor angiogenesis has become a clinical anti-cancer strategy in line with chemotherapy, radiotherapy and surgery, which underscore the critical importance of the angiogenic switch during early tumor development. Unfortunately the clinically approved anti-angiogenic drugs in use today are only effective in a subset of the patients, and many who initially respond develop resistance over time. Also, some of the anti-angiogenic drugs are toxic and it would be of great importance to identify alternative compounds, which could overcome these drawbacks and limitations of the currently available therapy. Finding "the most important target" may, however, prove a very challenging approach as the tumor environment is highly diverse, consisting of many different cell types, all of which may contribute to tumor angiogenesis. Furthermore, the tumor cells themselves are genetically unstable, leading to a progressive increase in the number of different angiogenic factors produced as the cancer progresses to advanced stages. As an alternative approach to targeted therapy, options to broadly interfere with angiogenic signals by a mixture of non-toxic natural compound with pleiotropic actions were viewed by this team as an opportunity to develop a complementary anti-angiogenesis treatment option. As a part of the "Halifax Project" within the "Getting to know cancer" framework, we have here, based on a thorough review of the literature, identified 10 important aspects of tumor angiogenesis and the pathological tumor vasculature which would be well suited as targets for anti-angiogenic therapy: (1) endothelial cell migration/tip cell formation, (2) structural abnormalities of tumor vessels, (3) hypoxia, (4) lymphangiogenesis, (5) elevated interstitial fluid pressure, (6) poor perfusion, (7) disrupted circadian rhythms, (8) tumor promoting inflammation, (9) tumor promoting fibroblasts and (10) tumor cell metabolism/acidosis. Following this analysis, we scrutinized the available literature on broadly acting anti-angiogenic natural products, with a focus on finding qualitative information on phytochemicals which could inhibit these targets and came up with 10 prototypical phytochemical compounds: (1) oleanolic acid, (2) tripterine, (3) silibinin, (4) curcumin, (5) epigallocatechin-gallate, (6) kaempferol, (7) melatonin, (8) enterolactone, (9) withaferin A and (10) resveratrol. We suggest that these plant-derived compounds could be combined to constitute a broader acting and more effective inhibitory cocktail at doses that would not be likely to cause excessive toxicity. All the targets and phytochemical approaches were further cross-validated against their effects on other essential tumorigenic pathways (based on the "hallmarks" of cancer) in order to discover possible synergies or potentially harmful interactions, and were found to generally also have positive involvement in/effects on these other aspects of tumor biology. The aim is that this discussion could lead to the selection of combinations of such anti-angiogenic compounds which could be used in potent anti-tumor cocktails, for enhanced therapeutic efficacy, reduced toxicity and circumvention of single-agent anti-angiogenic resistance, as well as for possible use in primary or secondary cancer prevention strategies.

A tumor-penetrating peptide enhances circulation-independent targeting of peritoneal carcinomatosis

Peritoneal carcinomatosis is a major source of morbidity and mortality in patients with advanced abdominal neoplasms. Intraperitoneal chemotherapy (IPC) is an area of intense interest given its efficacy in ovarian cancer. However, IPC suffers from poor drug penetration into peritoneal tumors. As such, extensive cytoreductive surgery is required prior to IPC. Here, we explore the utility of iRGD, a tumor-penetrating peptide, for improved tumor-specific penetration of intraperitoneal compounds and enhanced IPC in mice. Intraperitoneally administered iRGD significantly enhanced penetration of an attached fluorescein into disseminated peritoneal tumor nodules. The penetration was tumor-specific, circulation-independent, and mediated by the neuropilin-binding RXXK tissue-penetration peptide motif of iRGD. Q-iRGD, which fluoresces upon cleavage, including the one that leads to RXXK activation, specifically labeled peritoneal metastases displaying different growth patterns in mice. Importantly, iRGD enhanced intratumoral entry of intraperitoneally co-injected dextran to approximately 300% and doxorubicin to 250%. Intraperitoneal iRGD/doxorubicin combination therapy inhibited the growth of bulky peritoneal tumors and reduced systemic drug toxicity. iRGD delivered attached fluorescein and co-applied nanoparticles deep into fresh human peritoneal metastasis explants. These results indicate that intraperitoneal iRGD co-administration serves as a simple and effective strategy to facilitate tumor detection and improve the therapeutic index of IPC for peritoneal carcinomatosis.

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.

Research and clinical applications of molecular biomarkers in gastrointestinal carcinoma (Review)

Gastrointestinal (GI) carcinoma is a common malignant disease worldwide. Its development and progression is a multistage process involving a multifactorial etiology. Although the detailed mechanisms of the development of GI carcinoma remain controversial, the elucidation of its molecular biology over the last few years has resulted in a better perspective on its epidemiology, carcinogenesis and pathogenesis. More significantly, it is currently possible to use biological indicators or biomarkers in differential diagnosis, prognostic evaluation and specific clinical interventions. In this review, we aimed to describe the biomarkers of pathogenesis, invasion, metastasis and prognosis of GI carcinoma and discuss their potential clinical applications. The majority of these biomarkers, such as tumor-associated antigens, oncogenes and tumor suppressor genes, metastasis-associated genes, cell adhesion molecules, cytokines, growth factors and microRNAs, are currently broadly applicable.

Inflammation induced by MMP-9 enhances tumor regression of experimental breast cancer

Matrix metalloproteinases (MMPs) have been suggested as therapeutic targets in cancer treatment, but broad-spectrum MMP inhibitors have failed in clinical trials. Recent data suggest that several MMPs including MMP-9 exert both pro- and antitumorigenic properties. This is also the case of the natural inhibitors of MMPs, tissue inhibitor of metalloproteinases (TIMPs). The inhibitor of MMP-9 is TIMP-1, and high levels of this enzyme have been associated with decreased survival in breast cancer. Inflammation is one hallmark of cancer progression, and MMPs/TIMPs may be involved in the local immune regulation. We investigated the role of MMP-9/TIMP-1 in regulating innate antitumor immunity in breast cancer. Breast cancers were established in nude mice and treated with intratumoral injections of adenoviruses carrying the human TIMP-1 or MMP-9 gene (AdMMP-9). In vivo microdialysis for sampling of cancer cell-derived (human) and stroma-derived (murine) proteins, immunostainings, as well as cell cultures were performed. We report a dose-dependent decrease of tumor growth and angiogenesis after AdMMP-9 treatment. In addition to increased generation of endostatin, AdMMP-9 promoted an antitumor immune response by inducing massive neutrophil infiltration. Neutrophil depletion prior to gene transfer abolished the therapeutic effects of AdMMP-9. Additionally, AdMMP-9 activated tumor-infiltrating macrophages into a tumor-inhibiting phenotype both in vivo and in vitro. AdMMP-9 also inhibited tumor growth in immune-competent mice bearing breast cancers. Adenoviruses carrying the human TIMP-1 gene had no effect on tumor growth or the immune response. Our novel data identify MMP-9 as a potent player in modulating the innate immune response into antitumor activities.

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.

Suppressive effect of bevacizumab on peritoneal dissemination from gastric cancer in a peritoneal metastasis model

PURPOSE

Vascular endothelial growth factor (VEGF) has been reported to enhance vascular permeability and angiogenesis in the abdominal wall, thereby contributing to peritoneal dissemination with malignant ascites. We conducted this experimental study to find out if bevacizumab, a humanized monoclonal antibody against VEGF, had a suppressive effect on peritoneal dissemination from gastric cancer, in an experimental nude mouse model of peritoneal metastasis.

METHODS

Each mouse was treated with a single intraperitoneal (i.p.) injection of bevacizumab. Five mice were killed, and we measured their body weight, the mean number of tumor nodules, and the volume of ascites. We also extracted retroperitoneal tissues for histological examination, to count the frequency of mitosis, and to calculate the mitotic index. Another five mice were monitored until death, and their mean survival duration was calculated.

RESULTS

The volume of ascites and the mitotic index were significantly lower in the therapy group than in the nontherapy group (P = 0.042 and P < 0.01, respectively). The survival curve of the therapy group was significantly higher than that of the nontherapy group (P = 0.005).

CONCLUSION

Bevacizumab may suppress peritoneal dissemination from gastric cancer.

Tumor angiogenesis: insights and innovations

Angiogenesis is a vital process resulting in the formation of new blood vessels. It is normally a highly regulated process that occurs during human development, reproduction, and wound repair. However, angiogenesis can also become a fundamental pathogenic process found in cancer and several other diseases. To date, the inhibition of angiogenesis has been researched at both the bench and the bedside. While several studies have found moderate improvements when treating with angiogenesis inhibitors, greater success is being seen when the inhibition of angiogenesis is combined with other traditional forms of available therapy. This review summarizes several important angiogenic factors, examines new research and ongoing clinical trials for such factors, and attempts to explain how this new knowledge may be applied in the fight against cancer and other angiogenic-related diseases.

Adenoviral oncolytic suicide gene therapy for a peritoneal dissemination model of gastric cancer in mice

BACKGROUND

Peritoneal dissemination of gastric cancer is often refractory to systemic therapies. Although adenoviral gene therapy has been reported to be a potentially useful therapeutic modality, the adenovirus itself has a dose-limiting toxicity. A novel system was constructed using adenoviral oncolytic suicide gene therapy targeting carcinoembryonic antigen (CEA), and its therapeutic effect and the possibility to reduce the total viral dose while still preserving the antitumor effect were assessed.

METHODS

Three types of adenoviruses were prepared for this novel system: (A) Ad/CEA-Cre, (B) Ad/lox-CD::UPRT for a Cre/loxP system, and (C) Ad/CEA-E1 for conditionally replicating adenovirus. The antitumor effect of the oncolytic suicide gene therapy (A + B + C) was then evaluated in vitro. Mice bearing peritoneal dissemination of human gastric cancer were treated with either this system (A + B + C) or with a tenfold viral dose of suicide gene therapy (A + B). The adverse effects in terms of hepatotoxicity were then evaluated between the two groups.

RESULTS

The current system (A + B + C) demonstrated significantly better cytotoxic effect for CEA-producing cell lines than did suicide gene therapy (A + B) at the same viral dose in vitro. The effect of oncolytic suicide gene therapy was almost equal to that of the tenfold viral dose of suicide gene therapy in vivo. The hepatotoxicity of the two treated groups was also found to be equivalent.

CONCLUSION

It was possible to reduce the total adenoviral dose of oncolytic suicide gene therapy while still preserving the antitumor effect.

Advances in gastroma angiogenesis and antiangiogenesis treatment for gastric carcinoma

As a component of tumor stroma, tumor angiogenesis is not only essential to primary tumor growth but also one of the requisites to disseminate. Ultrastructural organization and immunohistochemisty have shown that density and quantity of blood vessels has a close association with the potentiality of tumor invasion and metastasis. Some recent studies confirm correlation between angiogenesis and invasion of gastric tumor, and some other studies prove that antiangiogenesis can significantly inhibit tumor growth and metastasis, which has demonstrated a promising application perspective for gastric carcinoma treatment.

Gene transfer of matrix metalloproteinase-9 induces tumor regression of breast cancer in vivo

Matrix metalloproteinases (MMP) are important regulators of angiogenesis and tumor progression by degradation of extracellular matrix. Clinical trials using MMP inhibitors have failed and recent studies suggest that MMPs may in contrast suppress tumor growth. It is not known, however, if MMPs or their inhibitors, tissue inhibitor of metalloproteinases (TIMP), can be used as therapy of established cancer. Here, adenovirus vectors carrying the human genes for MMP-9, TIMP-1, or empty controls were injected intratumorally in breast cancers established in mice supplemented with estradiol and treated with tamoxifen. Microdialysis was used to quantify MMP activity and sampling of endostatin and vascular endothelial growth factor (VEGF) in situ. We show that AdMMP-9 increased MMP activity in vivo, decreased tumor growth rate, and decreased microvessel area significantly. AdMMP-9 therapy resulted in significantly increased levels of endostatin in vivo, whereas VEGF levels were unaffected. As previously shown, tamoxifen exposure by itself increased MMP activity in all treatment groups. Moreover, the combined therapy with AdMMP-9 and tamoxifen further reduced tumor growth and increased the endostatin levels compared with either treatment alone. Gene transfer of TIMP-1 had no effects on tumor progression and counteracted the therapeutic effect of tamoxifen in our breast cancer model. This is the first report showing that overexpression of MMP-9 results in increased generation of antiangiogenic fragments, decreased angiogenesis, and therapeutic effects of established breast cancer.