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ABSTRACT: American women have a nearly 25% lifetime risk of developing breast cancer, with 20% to 40% of these patients developing life-threatening metastases. More than 70% of patients presenting with metastases have skeletal involvement, which signals progression to an incurable stage. Tumor-stroma cell interactions are only superficially understood, specifically regarding the ability of stromal cells to affect metastasis. In vivo models show that exogenously supplied human bone marrow-derived stem cells (hBMSC) migrate to breast cancer tumors, but no reports have shown endogenous hBMSC migration from the bone to primary tumors. Here, we present a model of in vivo hBMSC migration from a physiologic human bone environment to human breast tumors. Furthermore, hBMSCs alter tumor growth and bone metastasis frequency. These may home to certain breast tumors based on tumor-derived TGF-β1. Moreover, at the primary tumor level, interleukin 17B (IL-17B)/IL-17BR signaling may mediate interactions between hBMSCs and breast cancer cells.
Cancer Research 12/2010; 70(24):10044-50. · 7.86 Impact Factor
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ABSTRACT: The establishment of metastasis depends on the ability of cancer cells to acquire a migratory phenotype combined with their capacity to recreate a secondary tumor in a distant tissue. In epithelial cancers, such as those of the breast, the epithelial-mesenchymal transition (EMT) is associated with basal-like breast cancers, generates cells with stem-like properties, and enables cancer cell dissemination and metastasis. However, the molecular mechanism(s) that connects stem cell-like characteristics with EMT has yet to be defined. Using an orthotopic model of human breast cancer metastasis to lung, we identified a poor prognosis gene signature, in which several components of the wnt signaling pathway were overexpressed in early lung metastases. The wnt genes identified in this signature were strongly associated with human basal-like breast cancers. We found that inhibiting wnt signaling through LRP6 reduced the capacity of cancer cells to self-renew and seed tumors in vivo. Furthermore, inhibition of wnt signaling resulted in the reexpression of breast epithelial differentiation markers and repression of EMT transcription factors SLUG and TWIST. Collectively, these results provide a molecular link between self-renewal, EMT, and metastasis in basal-like breast cancers.
Cancer Research 07/2009; 69(13):5364-73. · 7.86 Impact Factor
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ABSTRACT: The high frequency and mortality associated with breast cancer metastasis to bone has motivated efforts to elucidate tumor-stroma interactions in the bone microenvironment contributing to invasion and proliferation of metastatic cells. The development of engineered tissues has prompted the integration of engineered bone scaffolds into animal models as potential targets for metastatic spread. Silk scaffolds were coupled with bone morphogenetic protein-2 (BMP-2), seeded with bone marrow stromal cells (BMSC), and maintained in culture for 7 weeks, 4 weeks, and 1 day before s.c. implant in a mouse model of human breast cancer metastasis from the orthotopic site. Following injection of SUM1315 cells into mouse mammary fat pads, tumor burden of implanted tissues was observed only in 1-day scaffolds. Scaffold development and implantation was then reinitiated to identify the elements of the engineered bone that contribute to metastatic spread. Untreated scaffolds were compared with BMP-2-coupled, BMSC-seeded, or BMP-2/BMSC-combined treatment. Migration of SUM1315 cells was detected in four of four mice bearing scaffolds with BMP-2 treatment and with BMSC treatment, respectively, whereas only one of six mice of the BMP-2/BMSC combination showed evidence of metastatic spread. Histology confirmed active matrix modeling and stromal cell/fibroblast infiltration in scaffolds positive for the presence of metastasis. These results show the first successful integration of engineered tissues in a model system of human breast cancer metastasis. This novel platform now can be used in continued investigation of the bone environment and stem cell contributions to the process of breast cancer metastasis.
Cancer Research 12/2007; 67(21):10304-8. · 7.86 Impact Factor
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ABSTRACT: RRR-alpha-tocopherol ether linked acetic acid analog (alpha-TEA), is a potential chemotherapeutic agent for ovarian cancer. Pro-death and pro-life signaling pathways were studied to understand the anti-cancer actions of alpha-TEA on cisplatin-sensitive (A2780S) and -resistant (A2780/cp70R) human ovarian cancer cells. Both cell lines were refractory to Fas; whereas, alpha-TEA sensitized them to Fas signaling. alpha-TEA increased levels of Fas message, protein and membrane-associated Fas. Neutralizing antibodies to Fas or Fas L partially blocked alpha-TEA-induced apoptosis. alpha-TEA induced prolonged activation of c-Jun N-terminal kinase (JNK) and its substrate c-Jun; Bax conformational change; and cleavage of Bid and caspases-8, -9 and -3. Chemical inhibitors of JNK, and caspases blocked alpha-TEA-induced apoptosis. alpha-TEA decreased phosphorylation of protein kinase B (Akt/PKB) and extracellular signal-regulated kinase (ERK1/2), as well as cellular FLICE-like inhibitory protein (c-FLIP) and Survivin protein levels. Knockdown of Akt and ERK activity using phosphoinositide- 3-kinase (PI3K) and mitogen-activated protein kinase kinase (MKK1) inhibitors enhanced alpha-TEA-induced apoptosis. Over-expression of constitutively active Akt2 and MKK1 blocked alpha-TEA-induced apoptosis. Collectively, data show alpha-TEA to be a potent apoptotic inducer of both cisplatin-sensitive and -resistant human ovarian cancer cells via activating death receptor Fas signaling and suppressing anti-apoptotic AKT and ERK targets.
APOPTOSIS 11/2006; 11(10):1813-23. · 4.79 Impact Factor
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ABSTRACT: A novel nonhydrolyzable ether-linked acetic acid analog of vitamin E, 2,5,7,8-tetramethyl-2R-(4R,8R,12-trimethyltridecyl)-chroman-6-yloxyacetic acid (alpha-TEA) in combination with cisplatin, reduces tumor burden of A2780/cp70 (cp70) cisplatin-resistant human ovarian cancer cells xenografted into immune compromised nude mice. Two xenograft studies were conducted using cp70 cells stably expressing green fluorescent protein (cp70-GFP) subcutaneously transplanted into NU/NU mice. For studies 1 and 2, alpha-TEA was formulated in liposomes and delivered by aerosol such that approximately 36 microg and 72 microg of alpha-TEA were deposited in the respiratory tract of each mouse each day, respectively. Cisplatin at 5 mg/kg was administered by intraperitoneal injections once weekly for the first 3 weeks in Study 1 and on the third and 10th days following treatment initiation in Study 2. The combination alpha-TEA + cisplatin treatment reduced tumor burden and metastasis of cp70-GFP cells in comparison to control mice or mice treated with alpha-TEA or cisplatin singly. A significant reduction (P < 0.001) in growth of subcutaneous transplanted tumors was obtained with alpha-TEA + cisplatin for both studies. Visible metastases were observed in the lungs of animals from control and cisplatin-treated groups but not in animals from the alpha-TEA- or alpha-TEA + cisplatin-treated groups. The alpha-TEA + cisplatin significantly reduced the total number of lung and axillary lymph node micrometastasis (P < 0.03 and P < 0.0001, respectively). Analyses of tumor sections showed the alpha-TEA + cisplatin treatment group, in comparison to control, to have a significantly lower level of cell proliferation (Ki-67 staining; P < 0.0001) and a significantly higher level of apoptosis (terminal deoxynucleotidyl transferase-mediated nick end labeling [TUNEL]; P < 0.0001). In summary, combinations of alpha-TEA + cisplatin significantly reduced tumor burden and metastases in a xenograft model of cisplatin-resistant human ovarian cancer cells. These data show promise for combination alpha-TEA + cisplatin chemotherapy for ovarian cancer.
Experimental Biology and Medicine 12/2004; 229(11):1169-76. · 2.64 Impact Factor
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ABSTRACT: A novel nonhydrolyzable ether derivative of RRR-alpha-tocopherol, RRR-alpha-tocopherol ether acetic acid analog [2,5,7,8-tetramethyl-2R-(4R,8R,12-trimethyltridecyl)chroman-6-yloxyacetic acid (alpha-TEA)], and a hydrolyzable ester derivative RRR-alpha-tocopheryl succinate (vitamin E succinate; VES) inhibited BALB/c mouse 66cl-4-GFP mammary tumor cell growth in vitro and in vivo. Treatment of 66cl-4-GFP cells in culture with alpha-TEA or VES induced dose-dependent DNA synthesis arrest and apoptosis and inhibited colony formation. Liposomal formulations of alpha-TEA delivered orally or by aerosol significantly reduced subcutaneous 66cl-4-GFP tumor burden and metastasis to lung and lymph nodes. Liposomal formulations of VES delivered by aerosol significantly reduced tumor burden and lung metastasis, but not lymph node metastasis. Unlike alpha-TEA, VES was ineffective in reducing tumor burden and metastasis to lungs and lymph nodes when administered orally. Analyses of tumor sections showed that alpha-TEA delivered by either method significantly reduced tumor cell proliferation as measured by Ki67, and increased apoptosis as measured by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL), whereas VES delivered by aerosol reduced tumor cell proliferation and increased apoptosis, but not significantly. In summary, the nonhydrolyzable ether vitamin E derivative alpha-TEA was effective in reducing tumor burden and metastasis when delivered either by aerosol or orally, whereas the hydrolyzable ester vitamin E derivative VES was effective only when delivered by aerosol.
Experimental Biology and Medicine 11/2004; 229(9):954-63. · 2.64 Impact Factor
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Karla A Lawson, Kristen Anderson,
Rachel M Snyder,
Marla Simmons-Menchaca,
Jeffrey Atkinson,
Lu-Zhe Sun,
Abhik Bandyopadhyay,
Vernon Knight,
Brian E Gilbert,
Bob G Sanders,
Kimberly Kline
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ABSTRACT: To test the anticancer properties of a nonhydrolyzable ether-linked acetic acid analogue of vitamin E, 2,5,7,8-tetramethyl-2R-(4R,8R, 12-trimethyltridecyl)chroman-6-yloxyacetic acid (alpha-TEA), and a derivative of camptothecin, 9-nitrocamptothecin (9-NC)singly and in combination against mouse mammary tumor cells (line 66 clone 4 stably transfected with green fluorescent protein; 66cl-4-GFP) cultured in vitro or transplanted subcutaneously into the inguinal region of female BALB/c mice to form established tumors.
Following in vitro treatment of 66cl-4-GFP cells with alpha-TEA and suboptimal concentrations of 9-NC, singly or in combination, apoptosis was measured by morphological evaluation of nuclei stained with 4',6-diamidino-2-phenylindole (DAPI), and DNA synthesis arrest was measured by tritiated thymidine uptake. For in vivo analyses alpha-TEA and 9-NC, both water-insoluble compounds, were formulated into liposomes using dil-auroylphosphatidylcholine and administered by aerosol to deliver doses calculated to be 36 and 0.4 microg/mouse per day, respectively, (singly or each separately for combined treatments) 7 days per week.
Treatment of 66cl-4-GFP cells in culture for 3 days with a combination of alpha-TEA (10 microg/ml; singly produces 38% apoptosis), and suboptimal concentrations of 9-NC(15.6, 31.3, 62.5, or 125 ng/ml; singly produce 2-7% apoptosis), produced 47%, 58%, 64%, and 69% apoptosis. Likewise, combinations of alpha-TEA 9-NC inhibited DNA synthesis more than either agent administered singly. A significant reduction (P< 0.001)in growth of subcutaneous transplanted tumors was observed with liposome-formulated and aerosolized delivery of alpha-TEA + 9-NC to BALB/c mice. The incidence of macroscopic lung metastasis was 83% in control vs 8 % in alpha-TEA-, 9-NC-, or combination-treated mice. Fluorescence microscopic examination of lungs and axillary and brachial lymph nodes showed a statistically significant decrease in metastasis observed in alpha-TEA-,9-NC-, and combination- vs control-treated animals. Analyses of primary tumor tissue for proliferation and apoptosis showed treatment groups to have lower Ki-67 and higher terminal deoxynucleotidyl transferase-mediated nick end labeling, respectively. Treatments showed no measurable effects on two angiogenesis parameters,namely intratumoral blood volume as assessed by hemoglobin content and intratumoral blood vessel density as assessed with CD31 staining.
Combination treatments enhanced antiproliferative and proapoptotic activities in cell culture, and when formulated in liposomes and delivered via aerosolization to treat an aggressive and metastatic syngeneic murine mammary tumor, the combination treatment showed a significant reduction in tumor volume in comparison to either treatment alone. Mechanistically, it appears that neither enhanced apoptosis, reduced cell proliferation,nor reduced blood vessel density can fully account for the enhanced effects of the combination treatment.
Cancer Chemotherapy and Pharmacology 11/2004; 54(5):421-31. · 2.83 Impact Factor
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ABSTRACT: A vitamin E derivative, vitamin E succinate (VES; RRR-alpha-tocopheryl succinate), and a vitamin E analogue, 2,5,7,8-tetramethyl-2R-(4R,8R,12-trimethyltridecyl)chroman-6-yloxy acetic acid (alpha-TEA), induce human breast, prostate, colon, lung, cervical, and endometrial tumor cells in culture to undergo apoptosis but not normal human mammary epithelial cells, immortalized, nontumorigenic breast cells, or normal human prostate epithelial cells. Human ovarian and cervical cancer cell lines are exceptions, with alpha-TEA exhibiting greater proapoptotic effects. Although both VES and alpha-TEA can induce A2780 and subline A2780/cp70 ovarian cancer cells to undergo DNA synthesis arrest within 24 h of treatment, only alpha-TEA is an effective inducer of apoptosis. VES or alpha-TEA treatment of cp70 cells with 5, 10, or 20 microg/ml for 3 days induced 5, 6, and 19% versus 9, 36, and 71% apoptosis, respectively. Colony formation data provide additional evidence that cp70 cells are more sensitive to growth inhibition by alpha-TEA than VES. Differences in stability of the ester-linked succinate moiety of VES versus the ether-linked acetic acid moiety of alpha-TEA were demonstrated by high-performance liquid chromatography analyses that showed alpha-TEA to remain intact, whereas VES was hydrolyzed to the free phenol, RRR-alpha-tocopherol. Pretreatment of cp70 cells with bis-(p-nitrophenyl) phosphate, an esterase inhibitor, before VES treatment, resulted in increased levels of intact VES and apoptosis. Taken together, these data show alpha-TEA to be a potent and stable proapoptotic agent for human ovarian tumor cells and suggest that endogenous ovarian esterases can hydrolyze the succinate moiety of VES, yielding RRR-alpha-tocopherol, an ineffective apoptotic-inducing agent.
Cancer Research 07/2004; 64(12):4263-9. · 7.86 Impact Factor
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ABSTRACT: A nonhydrolyzable ether analogue of RRR-alpha-tocopherol, 2,5,7,8-tetramethyl-2R-(4R, 8R, 12-trimethyltridecyl)chroman-6-yloxyacetic acid, called RRR-alpha-tocopheryloxyacetic acid or RRR-alpha-tocopherol ether-linked acetic acid analogue (alpha-TEA), exhibits antitumor activity in vitro and in vivo using a syngeneic BALB/c mouse mammary tumor model (line 66 clone 4 stably transfected with green fluorescent protein). Treatment of cells with 5, 10, and 20 micro g/ml alpha-TEA for 3 days produced 6, 34, and 50% apoptosis, respectively, and treatment of cells with 10 micro g/ml for 2, 3, 4, and 5 days produced 20, 35, 47, and 58% apoptosis, respectively. A liposomal formulation of alpha-TEA administered by aerosol reduced s.c. tumor growth and lung metastasis. Alpha-TEA-treated animals showed a significant decrease in tumor volumes over 17 days of aerosol treatment (P < 0.001). Forty percent of aerosol as well as untreated control mice had visible, macroscopic lung metastases versus none (0%) of the alpha-TEA-treated mice. On the basis of fluorescence microscopic examination of the surface (top and bottom) of flattened whole left lung lobes, an average of 60 +/- 15 and 102 +/- 17 versus 11 +/- 4 fluorescent microscopic metastases was observed in aerosol control and untreated control versus alpha-TEA-treated animals, respectively. Alpha-TEA formulated in ethanol + peanut oil (5 mg/mouse/day) delivered by gavage did not reduce s.c. primary tumor burden; however, fluorescent microscopic lung metastases were significantly reduced (P < 0.0021). In summary, alpha-TEA formulated in liposomes and delivered by aerosol is a potent antitumor agent and reduces lung metastasis.
Molecular Cancer Therapeutics 05/2003; 2(5):437-44. · 5.23 Impact Factor
