Mammary carcinoma cells produce pro-angiogenic factors to stimulate angiogenesis and tumor growth. Trefoil factor-3 (TFF3) is an oncogene secreted from mammary carcinoma cells and associated with poor prognosis. Herein, we demonstrate that TFF3 produced in mammary carcinoma cells functions as a promoter of tumor angiogenesis. Forced expression of TFF3 in mammary carcinoma cells promoted proliferation, survival, invasion and in vitro tubule formation of human umbilical vein endothelial cells (HUVEC). MCF7-TFF3 cells with forced expression of TFF3 generated tumors with enhanced microvessel density as compared to tumors formed by vector control cells. Depletion of TFF3 in mammary carcinoma cells by siRNA concordantly decreased the angiogenic behavior of HUVEC. Forced expression of TFF3 in mammary carcinoma cells stimulated IL-8 transcription and subsequently enhanced IL-8 expression in both mammary carcinoma cells and HUVEC. Depletion of IL-8 in mammary carcinoma cells with forced expression of TFF3, or antibody inhibition of IL-8, partially abrogated mammary carcinoma cell TFF3-stimulated HUVEC angiogenic behavior in vitro, as did inhibition of the IL-8 receptor, CXCR2. Depletion of STAT3 by siRNA in MCF-7 cells with forced expression of TFF3 partially diminished the angiogenic capability of TFF3 on stimulation of cellular processes of HUVEC. Exogenous recombinant hTFF3 also directly promoted the angiogenic behavior of HUVEC. Hence, TFF3 is a potent angiogenic factor and functions as a promoter of de novo angiogenesis in mammary carcinoma, which may co-coordinate with the growth promoting and metastatic actions of TFF3 in mammary carcinoma to enhance tumor progression.

The waveform-detection technique detects rotor position in variable-reluctance motors indirectly by monitoring rise or fall times of the chopped phase current waveform. The chop rise and fall times can be either of an active or inactive phase. The drawbacks of monitoring chop current rise and fall times of an active phase have already been analyzed and presented in [2], [3], [4].In this paper an investigation is made for using chop phase current rise time of an inactive phase for rotor position detection. A digital controller based on the waveform-detection technique which uses the inactive phase chop current rise time is implemented. The analysis together with experimental results obtained by applying the controller to drive a 3-phase VR step motor suggest that: the use of chop current rise-time leads to instability in the drive system and hence is not recommended. On the other hand, chop fall-time provides stable operation and therefore, is recommended. An algorithm implemented to start and run the VR step motor from stand-still position maintaining correct direction of rotation is also presented.

Mammary carcinoma cells produce various growth factors that stimulate endothelial cells to promote angiogenesis in mammary carcinoma. Trefoil Factor 3 (TFF3) is a small secreted protein which is involved in protection of the gastrointestinal tract against mucosal damage. Our laboratory has also previously identified TFF3 as an orthotopically expressed oncogene in mammary carcinoma and observed that TFF3 stimulated oncogenicity and invasiveness of mammary carcinoma cells. Several studies have reported a significant positive association between TFF3 protein expression and microvessel density. However, the potential functional role of TFF3 in mammary carcinoma angiogenesis has not been determined. Herein, we defined the functional effect of TFF3 secreted by mammary carcinoma cells on the behavior of endothelial cells in de novo tumor angiogenesis. We utilized MCF-7 and T47D cells as our in vitro models by stable forced expression of TFF3 or siRNA mediated depletion of TFF3 in these cell lines. The effect of TFF3 secreted from mammary carcinoma cells on human umbilical vein endothelial cells (HUVEC) was determined by using a co-culture transwell system, whereby HUVEC cells were co-cultured with mammary carcinoma cells. We demonstrated that TFF3 secreted from mammary carcinoma cells promoted HUVEC cells monolayer cell cycle progression and proliferation, survival, migration, invasion, and in vitro tubule formation. In a xenograft model, mammary carcinoma cells with forced expression of TFF3 produced tumors with increased microvessel density (CD31 and CD34) compared to tumors formed by control cells. Depletion of TFF3 in mammary carcinoma cells by siRNA or inhibition with anti-TFF3 polyclonal antibody significantly decreased HUVEC cells monolayer cell cycle progression and proliferation, migration, invasion, and in vitro tubule formation. Mechanistically, we observed that TFF3 increased IL-8 expression in mammary carcinoma cells with forced expression of TFF3. Depletion of IL-8 in mammary carcinoma cells by siRNA or inhibition with anti-IL8 monoclonal antibody significantly decreased migration, invasion, and in vitro tubule formation of HUVEC cells promoted by TFF3. Hence, TFF3 is a promoter of tumor angiogenesis, which may co-coordinate with the growth promoting and metastatic actions of TFF3 in mammary carcinoma to enhance tumor progression. Citation Format: Wai-Hoe Lau, Vijay Pandey, Xiangjun Kong, Arindam Banerjee, Tao Zhu, Peter E. Lobie. Trefoil factor 3 promotes angiogenesis in mammary carcinoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1020. doi:10.1158/1538-7445.AM2014-1020