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Journal Article

*Breast Cancer; *Chemotherapy; *Genes; *Luciferase; Anatomy and Physiology; Biochemistry; Bioware; Cells(Biology); Diseases; Drugs; Efficacy; Gel Polymers; Gels; Growth(Physiology); Humans; Image Processing; In Vitro Analysis.; In Vivo Analysis; Luciferase Genes; Medicine and Medical Research; Metastasis; Mouse Models; Paclitaxel Sensitivity; Poloxamer Polymers; Polymers; Preclinical Evaluations; surgery; Synergism; Toxicity; Tumor Cell Lines

This project evaluated paclitaxel chemotherapy delivery from a gel polymer system placed into a wound bed following conservative (marginal) surgical removal of human breast cancers grown in nude mice. This delivery method was shown to control local tumor disease as well as assist in control of systemic metastasis. We established 5 human breast cancer cell lines within our laboratory. We elected purchase and implement a unique (luciferase) imaging system which allows in vivo imaging of tumor growth and metastasis (and subsequently decrease animal use). Tumor cell lines were transfected with the luciferase gene. In vitro testing of cell lines established paclitaxel sensitivity and showed a synergistic effect of delivering paclitaxel by the poloxamer polymer, especially for the chemotherapy resistant cell line, MCF-7-ADR. We completed the simultaneous evaluation of local and systemic toxicity, local, regional and systemic distribution and local and systemic efficacy of locally delivered paclitaxel chemotherapy following tumor removal using the MCF-7-ADR cell line in nude mice. Intracavitary administration of taxol in poloxamer was well tolerated (locally and systemically) afld resulted in significantly improved control of local tumor regrowth and comparable control of metastasis following marginal tumor removal as compared to intravenous paclitaxel (parent drug) . Sustained drug levels (from polymer delivery) were seen in plasma and liver tissue at 60 days.

Journal Article

Animals; Bioware; Breast Neoplasms; Disease Models, Animal; Female; Humans; Luciferases; Mammary Neoplasms, Animal; MDA-MB-231-D3H1 cells; Mice; Mice, Nude; Neoplasm Metastasis; Plasmids; Transplantation, Heterologous; Tumor Cells, Cultured

INTRODUCTION Our goal was to generate xenograft mouse models of human breast cancer based on luciferase-expressing MDA-MB-231 tumor cells that would provide rapid mammary tumor growth; produce metastasis to clinically relevant tissues such as lymph nodes, lung, and bone; and permit sensitive in vivo detection of both primary and secondary tumor sites by bioluminescent imaging. METHOD Two clonal cell sublines of human MDA-MB-231 cells that stably expressed firefly luciferase were isolated following transfection of the parental cells with luciferase cDNA. Each subline was passaged once or twice in vivo to enhance primary tumor growth and to increase metastasis. The resulting luciferase-expressing D3H1 and D3H2LN cells were analyzed for long-term bioluminescent stability, primary tumor growth, and distal metastasis to lymph nodes, lungs, bone and soft tissues by bioluminescent imaging. Cells were injected into the mammary fat pad of nude and nude-beige mice or were delivered systemically via intracardiac injection. Metastasis was also evaluated by ex vivo imaging and histologic analysis postmortem. RESULTS The D3H1 and D3H2LN cell lines exhibited long-term stable luciferase expression for up to 4-6 months of accumulative tumor growth time in vivo. Bioluminescent imaging quantified primary mammary fat pad tumor development and detected early spontaneous lymph node metastasis in vivo. Increased frequency of spontaneous lymph node metastasis was observed with D3H2LN tumors as compared with D3H1 tumors. With postmortem ex vivo imaging, we detected additional lung micrometastasis in mice with D3H2LN mammary tumors. Subsequent histologic evaluation of tissue sections from lymph nodes and lung lobes confirmed spontaneous tumor metastasis at these sites. Following intracardiac injection of the MDA-MB-231-luc tumor cells, early metastasis to skeletal tissues, lymph nodes, brain and various visceral organs was detected. Weekly in vivo imaging data permitted longitudinal analysis of metastasis at multiple sites simultaneously. Ex vivo imaging data from sampled tissues verified both skeletal and multiple soft tissue tumor metastasis. CONCLUSION This study characterized two new bioluminescent MDA-MB-231-luc human breast carcinoma cell lines with enhanced tumor growth and widespread metastasis in mice. Their application to current xenograft models of breast cancer offers rapid and highly sensitive detection options for preclinical assessment of anticancer therapies in vivo.

Journal Article

Animals; Bioware; Chromatography, Liquid; Cyclin-Dependent Kinase 4; Drug Stability; Female; Humans; MDA-MB-231-D3H1 cells; Mice; Mice, SCID; Neoplasm Transplantation; Neoplasms, Experimental; Piperazines; Protein kinase inhibitors; Pyridines; Sensitivity and Specificity; Tandem Mass Spectrometry; Transplantation, Heterologous

Phase II attrition of clinical candidates in the drug development cycle is currently a major issue facing the pharmaceutical industry. To decrease phase II attrition, there is an increased emphasis on validation of mechanism of action, development of efficacy models and measurement of drug levels at the site of action. PD 0332991, a highly specific inhibitor of cyclin-dependent kinase 4 (CDK-4) is currently in clinical development for the treatment of solid tumor. A clinical presurgical study will be required to better understand how PD 0332991 affects signaling pathways and how the intratumoral concentration of PD 0332991 correlates with plasma PK parameters and molecular alterations in breast cancer tissues after PD 0332991 treatment. Before conducting such a clinical study, it is important to evaluate PD 0332991 levels in tumor tissue samples from a xenograft mouse model for the determination of drug exposure at the site of action. Therefore, the objectives of this study were (1) to develop and validate a sensitive LC-MS/MS method to quantify PD 0332991 in mouse tumor tissues from MDA-MB-231-Luc human breast tumor xenografts in SCID-beige mice; (2) to quantify PD 0332991 levels in mouse tumor tissues after oral administration of PD 0332991 at 10 and 100mg/kg using the validated LC-MS/MS method. Both liquid-liquid extraction (LLE) and supported liquid extraction (SLE) in a 96-well format were developed and evaluated to achieve optimal extraction recovery with minimal matrix effects. The newly developed SLE method is more efficient (speed and ease) and demonstrates comparable recovery (93.1-100% at three different concentrations) compared to the traditional LLE method. The validated LC-MS/MS for PD 032291 in mouse tumor tissue homogenate method exhibited a linear dynamic range of 0.1-100 ng/mL with inter-day accuracy and precision within 15%. The validated method was successfully applied to measure PD 0332991 levels in tumor tissues in MDA-MB-231-Luc human breast tumor xenografts in SCID beige mice. The mean tumor concentrations at 6h post-oral PD 0332991 administration at 10 and 100mg/kg were 1793 (+/-1008) and 25,163 (+/-3959) ng/g, respectively.

Journal Article

Animals; Bioware; Breast Neoplasms; Cell Line, Tumor; Fluorescence; Fluorescent Dyes; Humans; Liposomes; Magnetic Resonance Imaging; Magnetics; MDA-MB-231-D3H1 cells; Mice; Mice, Inbred Strains; Microscopy, Confocal; Molecular Probes; Optics and Photonics; Transferrin; Xenograft Model Antitumor Assays

A dual probe with fluorescent and magnetic reporter groups was constructed by linkage of the near-infrared (NIR) fluorescent transferrin conjugate (Tf(NIR)) on the surface of contrast agent-encapsulated cationic liposome (Lip-CA). This probe was used for magnetic resonance imaging (MRI) and optical imaging of MDA-MB-231-luc breast cancer cells grown as a monolayer in vitro and as solid tumor xenografts in nude mice. Confocal microscopy, optical imaging, and MRI showed a dramatic increase of in vitro cellular uptake of the fluorescent and magnetic reporter groups from the probe compared with the uptake of contrast agent or Lip-CA alone. Pretreatment with transferrin (Tf) blocked uptake of the probe reporters, indicating the importance and specificity of the Tf moiety for targeting. Intravenous administration of the dual probe to nude mice significantly enhanced the tumor contrast in MRI, and preferential accumulation of the fluorescent signal was clearly seen in NIR-based optical images. More interestingly, the contrast enhancement in MRI showed a heterogeneous pattern within tumors, which reflected the tumor's morphologic heterogeneity. These results indicate that the newly developed dual probe enhances the tumor image contrast and is superior to contrast agent alone for identifying the tumor pathologic features on the basis of MRI but also is suitable for NIR-based optical imaging.

Journal Article

Animals; Bioware; Cell Line, Tumor; Cell Proliferation; Female; Humans; Insulin; Lung Neoplasms; Lymphangiogenesis; MDA-MB-231-D3H1 cells; Mice; Neoplasm Metastasis; Neoplasms, Experimental; Neovascularization, Pathologic; Phosphorylation; Proto-Oncogene Proteins c-akt; Receptor, Insulin; RNA, Small Interfering; Vascular Endothelial Growth Factor A

Insulin receptor (IR) and the type I IGF receptor (IGF1R) are structurally and functionally related. The function of IGF1R in cancer has been well documented and anti-IGF1R strategies to treat cancer have shown initial positive results. However, the role of IR in tumor biology, independent of IGF1R, is less clear. To address this issue, short hairpin RNA (shRNA) was used to specifically downregulate IR in two cancer cell lines, LCC6 and T47D. Cells with reduced IR showed reduced insulin-stimulated Akt activation, without affecting IGF1R activation. Cells with reduced IR formed fewer colonies in anchorage-independent conditions. LCC6 IR shRNA xenograft tumors in mice had reduced growth, angiogenesis and lymphangiogensis when compared with LCC6 wild-type cells. Accordingly, LCC6 IR shRNA clones produced less hypoxia-inducible factor-1alpha, vascular endothelial growth factor (VEGF)-A and VEGF-D. Furthermore, LCC6 IR shRNA cells formed fewer pulmonary metastases when compared with LCC6 wild-type cells. Using in vivo luciferase imaging, we have shown that LCC6 IR shRNA cells have less seeding and colonization potential in the lung and liver of mice than LCC6 cells. In conclusion, downregulation of IR inhibited cancer cell proliferation, angiogenesis, lymphangiogenesis and metastasis. Our data argue that IR should also be targeted in cancer therapy.