Urethane-induced Mammary Carcinogenesis Susceptibility in Transgenic Mice Expressing a Dominant-negative TGF-β Type II Receptor.

Background/aim: Transforming growth factor-β (TGF-β) plays dual suppressive and oncogenic roles in mammary carcinogenesis.

Materials And Methods: To analyze whether TGF-β exerts suppressive or oncogenic actions on mammary carcinogenesis, transgenic mice overexpressing a dominant-negative mutant type II TGF-β receptor (TβRII-DNR) driven by the mouse mammary tumor virus (MMTV) promoter were treated with a low dose of urethane, a carcinogen present in fermented food products and alcoholic beverages.

Results: Lobular proliferative lesions, showing high β-casein expression, developed in the mammary glands of TβRII-DNR mice aged >61 weeks.

Synthetic α-mangostin dilaurate strongly suppresses wide-spectrum organ metastasis in a mouse model of mammary cancer.

We previously reported that, in a mouse model of mammary cancer, α-mangostin alone exhibits anti-metastatic properties. To enhance this anti-metastatic effect, we examined the efficacy of synthetic α-mangostin dilaurate (MGD), prepared by adding lauric acid to α-mangostin, in the same experimental system wherein mice bearing mammary tumors are exposed to dietary MGD at 0, 2000 and 4000 ppm. Lauric acid has a high propensity for lymphatic absorption, which is the most common pathway of initial dissemination of many solid malignancies.

Therapy with siRNA for Vegf-c but not for Vegf-d suppresses wide-spectrum organ metastasis in an immunocompetent xenograft model of metastatic mammary cancer.

Cancer metastasis contributes significantly to cancer mortality and is facilitated by lymphangiogenesis and angiogenesis. Vascular endothelial growth factors-C and D (VEGF-C and VEGF-D) are heavily involved in lymphangiogenesis. Using small interfering RNA (siRNA) against mouse Vegf-c, and Vegf-d, we sought to inhibit metastasis in a model of metastatic murine mammary cancer.

Lymphangiogenesis and Axillary Lymph Node Metastases Correlated with VEGF-C Expression in Two Immunocompetent Mouse Mammary Carcinoma Models.

Lymphangiogenesis and the expression of vascular endothelial cell growth factor C (VEGF-C) in tumors have been considered to be causally promoting lymphatic metastasis. There are only a few studies on lymphatic metastasis in immunocompetent allograft mouse models. To study the relationship between VEGF-C-mediated lymphangiogenesis and axillary lymph node metastasis, we used two mouse mammary carcinoma cell lines; the BJMC338 has a low metastatic propensity, whereas the BJMC3879 has a high metastatic propensity although it originated from the former cell line.

α-Mangostin extracted from the pericarp of the mangosteen (Garcinia mangostana Linn) reduces tumor growth and lymph node metastasis in an immunocompetent xenograft model of metastatic mammary cancer carrying a p53 mutation.

Background: The mangosteen fruit has a long history of medicinal use in Chinese and Ayurvedic medicine. Recently, the compound α-mangostin, which is isolated from the pericarp of the fruit, was shown to induce cell death in various types of cancer cells in in vitro studies. This led us to investigate the antitumor growth and antimetastatic activities of α-mangostin in an immunocompetent xenograft model of mouse metastatic mammary cancer having a p53 mutation that induces a metastatic spectrum similar to that seen in human breast cancers.

Sunitinib suppresses tumor growth and metastases in a highly metastatic mouse mammary cancer model.

Background: Sunitinib is an inhibitor that blocks tyrosine phosphorylation (p-Tyr) of receptors including vascular endothelial growth factor receptor (VEGFR) and platelet-derived growth factor receptor. Sunitinib suppresses angiogenesis and cell proliferation and is an effective treatment for renal cell carcinoma and gastrointestinal stromal tumors. In the present study, we examined the antitumor and antimetastatic activities of sunitinib in mouse metastatic mammary cancer.

The endogenous soluble VEGF receptor-2 isoform suppresses lymph node metastasis in a mouse immunocompetent mammary cancer model.

Background: Cancer metastasis contributes significantly to cancer mortality and is facilitated by lymphangiogenesis and angiogenesis. A new splicing variant, endogenous soluble vascular endothelial growth factor receptor-2 (esVEGFR-2) that we recently identified is an endogenous selective inhibitor of lymphangiogenesis. To evaluate the antimetastatic potential of esVEGFR-2, gene therapy with vector expressing esVEGFR-2 (pesVEGFR-2) or endostatin (pEndo) as a positive control was conducted on murine metastatic mammary cancer.

Raloxifene inhibits tumor growth and lymph node metastasis in a xenograft model of metastatic mammary cancer.

Background: The effects of raloxifene, a novel selective estrogen receptor modulator, were studied in a mouse metastatic mammary cancer model expressing cytoplasmic ERα.

Methods: Mammary tumors, induced by inoculation of syngeneic BALB/c mice with BJMC3879luc2 cells, were subsequently treated with raloxifene at 0, 18 and 27 mg/kg/day using mini-osmotic pumps.

Results: In vitro study demonstrated that the ERα in BJMC3879luc2 cells was smaller (between 50 and 64 kDa) than the normal-sized ERα (66 kDa) and showed cytoplasmic localization.

An immunocompetent murine model of metastatic mammary cancer accessible to bioluminescence imaging.

Background: Many areas of research, including gene and pharmacological therapeutics, would benefit from longitudinal in vivo monitoring methodologies. To investigate the feasibility of one such methodology, we developed a murine mammary cancer model amenable to sequential bioluminescent imaging of tumor growth and metastasis in living animals.

Materials And Methods: Metastatic mouse mammary carcinoma BJMC3879 cells were transfected to stably express firefly luciferase and inoculated into immunocompetent female BALB/c mice.

Panaxanthone isolated from pericarp of Garcinia mangostana L. suppresses tumor growth and metastasis of a mouse model of mammary cancer.

Background: The antitumor growth and antimetastatic activity of panaxanthone (approximately 80% alpha-mangostin and 20% gamma-mangostin) were studied in a mouse metastatic mammary cancer model that produces a metastatic spectrum similar to that seen in human breast cancer.

Materials And Methods: Mammary tumors, induced by inoculation of syngeneic BALB/c mice with BJMC3879 cells, were subsequently treated with panaxanthone at 0, 2,500, or 5,000 ppm in their diet. In vitro studies were also conducted to evaluate the effects of alpha-mangostin, the main component of panaxanthone, on BJMC3879 cells.

Easy stable transfection of a human cancer cell line by electrogene transfer with an Epstein-Barr virus-based plasmid vector.

We report an easy and stable transfection technique using electrogene transfer with a nonviral Epstein-Barr (EB) virus-based vector. To achieve stable transfection of human breast cancer cells, we conducted electrogene transfer of an EB virus-based plasmid vector (reduced size of oriP) containing the enhanced green fluorescence protein (eGFP) gene. Because the EB virus-based vector exhibits high transfer efficiency and strong persistent transgene expression as a result of autonomous replication in human cells, and as Nucleofector electrogene transfer can achieve highly efficient gene transfection, this method is particularly suitable for generation of stably transfected cell lines.

Vaticanol C, a novel resveratrol tetramer, reduces lymph node and lung metastases of mouse mammary carcinoma carrying p53 mutation.

Purpose: The effects of vaticanol C (Vat-C), a novel resveratrol tetramer, were studied in a mouse metastatic mammary cancer model carrying mutations in p53 that produce a metastatic spectrum similar to that seen in human breast cancers.

Methods: Mammary tumors, induced by inoculation of syngeneic BALB/c mice with BJMC3879 cells, were subsequently treated with Vat-C at 0, 100 and 200 ppm in their diet.

Results: The in vitro study demonstrated that Vat-C induced apoptosis, as inferred by morphological changes, nucleosomal DNA fragmentation and elevated activities of caspases.

COX-2 inhibitor celecoxib suppresses tumor growth and lung metastasis of a murine mammary cancer.

Background: The antitumor growth and antimetastatic actions of celecoxib [a selective cyclooxygenase-2 (COX-2) inhibitor] were investigated in a metastatic murine mammary cancer model.

Materials And Methods: Mice bearing mammary tumors, developed after inoculation of syngeneic BALBIc mice with a mammary carcinoma cell line carrying a p53 mutation, were treated with celecoxib at 0, 7.5 and 15 mg/kg five times a week for seven weeks.

Expression of Vicia villosa agglutinin (VVA)-binding glycoprotein in primary breast cancer cells in relation to lymphatic metastasis: is atypical MUC1 bearing Tn antigen a receptor of VVA?

Aberrant carbohydrate expression frequently occurs in breast cancer and may endow cells with metastatic potential. Here we first studied the relationship between expression of Vicia villosa agglutinin (lectin) (VVA)-binding carbohydrates and aggressive breast cancer. We then investigated the molecular characteristics of these glycoproteins and compared them with those of glycoproteins recognized by the mouse anti-Tn monoclonal antibody (MAb) HB-Tn1.

In vivo electrogene transfer of interleukin-12 inhibits tumor growth and lymph node and lung metastases in mouse mammary carcinomas.

Background: Human breast cancer metastasizes mainly to lymph nodes, lungs, liver, and bone; in the majority of cases, it is the development of metastases which leads to death. In order to suppress mammary cancer metastasis, we applied in vivo electrogene transfer (non-viral method) as a means of interleukin-12 (IL-12) gene therapy on highly metastatic murine mammary cancer model.

Methods: Metastatic mammary tumors induced by inoculation in BALB/c female mice were treated by intratumoral injections of either a plasmid vector containing IL-12 or empty vector and then subjected to in vivo electrogene transfer once a week for 8 weeks.

Lack of polymorphism in MUC1 tandem repeats in cancer cells is related to breast cancer progression in Japanese women.

MUC1 is a transmembrane molecule characterized by a repeated sequence of 20 amino acid (TAP PAHGVTSAPDTRPAPGS). Abnormal overexpression of MUC1 in cancer cells is thought to contribute to their aggressive growth, but molecular mechanisms associated with this effect are still unclear. Our current study aimed to clarify whether MUC1 expression as recognized by VU-3C6 anti-MUC1 mouse IgG monoclonal antibody (MAb) with a dominant epitope of 12 amino acids: GVTSAPDTRPAP, correlated with aggressive properties of human breast cancer.

Electrogene transfer of an Epstein-Barr virus-based plasmid replicon vector containing the diphtheria toxin A gene suppresses mammary carcinoma growth in SCID mice.

Experimental mammary cancer therapy in mice was conducted using electrogene transfer of a non-viral EBV-based plasmid vector (reduced size of the oriP gene), containing the DT-A gene. Because the EBV-based plasmid vector exhibits high transfer efficiency and strong persistent transgene expression due to autonomous replication in human cells, it is particularly suitable as a tool for cancer gene therapy. In vitro, 79% of MDA-MB231 human mammary carcinoma cells died as a result of the EBV-based vector containing DT-A (pEB-DTA) by 48 h after transfection.

Roles of CXC chemokines and macrophages in the recruitment of inflammatory cells and tumor rejection induced by Fas/Apo-1 (CD95) ligand-expressing tumor.

The role of CD95 ligand (FasL/Apo-1L)-expressing tumors in immunosuppression or immunopotentiation is controversial. CD95L-transfected tumors induce immunopotentiation after vigorous neutrophil infiltration. Thus, the induction of neutrophil infiltration by CD95L seems to play an important role in tumor rejection.

Experimental gene therapy in mammary and urinary bladder cancer using electrogene transfer.

We investigated the effectiveness of in vivo electrogene transfer as a means of therapy in rat urinary bladder carcinoma and in mammary carcinoma models in both athymic and syngeneic mice using the herpes simplex virus 1 thymidine kinase (HSVtk) or IL-12 genes in combination with ganciclovir (GCV). A significant increase in the levels of tissue apoptosis and necrosis was induced with a single injection of HSVtk vector directly into bladder and mammary tumors followed by in vivo transfection and a regimen of intraperitoneal GCV injection. This procedure induced significant selective tumor cell death, characterized by marked inflammation and peripheral macrophage influx.

Lovastatin inhibits tumor growth and lung metastasis in mouse mammary carcinoma model: a p53-independent mitochondrial-mediated apoptotic mechanism.

The effects of lovastatin, a potent inhibitor of hydroxymethylglutaryl-coenzyme A reductase, were studied in a mouse model of metastatic mammary cancer carrying a p53 mutation. Mice bearing mammary tumors, induced by inoculation of syngeneic BALB/c mice with BJMC3879 cells, were treated with lovastatin at 0, 25 and 50 mg/kg three times a week. Tumor volumes were significantly reduced in a dose-dependent manner throughout the 6 week study and were associated with both a decrease in DNA synthesis and an increase in apoptosis.

Selective cancer cell apoptosis induced by FTY720; evidence for a Bcl-dependent pathway and impairment in ERK activity.

Background: FTY720 is a unique immunosuppressant that induces apoptosis in activated lymphocytes, but not in other hematopoietic cells. We conducted the present study to investigate its anticancer effect and molecular pathway in inducing apoptosis using murine breast cancer models.

Materials And Methods: The difference in drug susceptibility to FTY720 between cancer cells and non-cancer cells was examined by MTT assay and cell growth assay.

Massive apoptotic cell death in chemically induced rat urinary bladder carcinomas following in situ HSVtk electrogene transfer.

Background: Gene delivery in current gene therapy studies relies largely on recombinant viral vectors. However, the safety of this method is still under investigation. The effectiveness of in vivo electrogene transfer as a means of gene therapy for rat bladder cancers using the herpes simplex virus 1 thymidine kinase (HSVtk) gene in combination with ganciclovir (GCV) was therefore investigated.

Suppression of murine mammary carcinoma growth and metastasis by HSVtk/GCV gene therapy using in vivo electroporation.

The effectiveness of electroporation as a means of gene transfection, both in vitro and in vivo, was tested using the herpes simplex virus 1 thymidine kinase (HSVtk) gene in combination with ganciclovir (GCV) administration as therapy against murine mammary cancer. Approximately 80% of BJMC3879 metastatic mammary carcinoma cells, derived from MMTV-infected BALB/c mice, died as a result of HSVtk/GCV treatment 72 hours after the transfection; decreased DNA synthesis was also seen. Mammary tumors induced by inoculation of syngeneic mice with BJMC3879 cells were subsequently treated by direct injection of vector containing HSVtk (pHSVtk) alone, empty vector or saline alone twice a week.

Marked prevention of tumor growth and metastasis by a novel immunosuppressive agent, FTY720, in mouse breast cancer models.

FTY720 is a unique immunosuppressive agent that exerts its activity by inducing apoptosis in lymphocytes. We conducted the present study to investigate the effects of FTY720 on cancer growth and metastasis, as well as its mechanism of action. In vitro treatment with FTY720 induced dramatic cancer cell apoptosis in a mouse breast cancer cell line, JygMC(A).