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The relationship between obesity and breast cancer (BC) has focused on serum factors. However, the mammary gland contains adipose tissue (AT) which may enable the crosstalk between adipocytes and tumor cells contributing to tumor macrophage recruitment. We hypothesize that the breast AT (bAT) is inflamed in obese females and plays a major role in breast cancer development. The effects of this interplay on macrophage chemotaxis were examined in vitro, using co-cultures of mouse macrophages, mammary tumor cells and adipocytes. Macrophages were exposed to the adipocyte and tumor paracrine factors leptin, CCL2 and lauric acid (alone or in combinations). In cell supernatants Luminex identified additional molecules with chemotactic and other pro-tumor functions. Focus on the adipokine leptin, which has been shown to have a central role in breast cancer pathogenesis, indicated it modulates macrophage phenotypes and functions. In vivo experiments demonstrate that mammary tumors from obese mice are larger and that bAT from obese tumor-bearers contains higher numbers of macrophages/CLS and hypertrophic adipocytes than bAT from lean tumor-bearers, thus confirming it is more inflamed. Also, bAT distal from the tumor is more inflamed in obese than in lean mice. Our results reveal that bAT plays a role in breast cancer development in obesity.

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A gradual decline in insulin response is known to precede the onset of type 1 diabetes (T1D). To track age-related changes in the β-cell function of non-obese diabetic (NOD) mice, the most commonly used animal model for T1D, and to establish differences between those who do and do not become hyperglycemic, we performed a long-term longitudinal oral glucose tolerance test (OGTT) study (10–42 weeks) in combination with immunofluorescence imaging of islet morphology and cell proliferation. We observed a clear biphasic decline in insulin secretion (AUC0–30min) even in euglycemic animals. A first phase (10–28 weeks) consisted of a relatively rapid decline and paralleled diabetes development in the same cohort of animals. This was followed by a second phase (29–42 weeks) during which insulin secretion declined much slower while no additional animals became diabetic. Blood glucose profiles showed a corresponding, but less pronounced change: the area under the concentration curve (AUC0–150min) increased with age, and fit with a bilinear model indicated a rate-change in the trendline around 28 weeks. In control NOD scids, no such changes were observed. Islet morphology also changed with age as islets become surrounded by mononuclear infiltrates, and, in all mice, islets with immune cell infiltration around them showed increased β-cell proliferation. In conclusion, insulin secretion declines in a biphasic manner in all NOD mice. This trend, as well as increased β-cell proliferation, is present even in the NODs that never become diabetic, whereas, it is absent in control NOD scid mice.

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We have reported that interferon-alpha inhibits HPV-18 mRNA in HeLa cells. Here we examine mechanisms by which IFN could modulate HPV expression. In northern blot experiments, we observed that interferon-alpha 2b treatment reduced HPV-18 mRNA levels in a time- and dose-dependent manner, with a maximal effect achieved at 48 h. Simultaneously, induction of 2-5A synthetase mRNA was verified as indicative of IFN action. The IFN regulatory effect on HPV-18 mRNA at 48 h required de novo protein synthesis. We performed run-on experiments to determine whether the IFN regulatory effect was at the transcriptional level. HPV-18 endogenous transcription was repressed using 200 and 1000 IU/ml. Interferon treatment did not affect HPV-18 mRNA stability, at least under our experimental conditions. To verify whether HPV-18 enhancer sequences were involved in the interferon effect, we transfected a construct containing the chloramphenicol acetyltransferase driven by the HPV-18 upstream regulatory region. The enzyme activity was unmodified on human keratinocytes and HeLa cells by interferon exposition. Our data demonstrate that interferon-alpha downregulates HPV-18 mRNA levels on HeLa cells by repressing nascent viral transcripts, possibly through regulatory cellular flanking regions.

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