The normal breast microenvironment of premenopausal women differentially influences the behavior of breast cancer cells in vitro and in vivo

<p>Abstract</p> <p>Background</p> <p>Breast cancer studies frequently focus on the role of the tumor microenvironment in the promotion of cancer; however, the influence of the normal breast microenvironment on cancer cells remains relatively unknown. To investigate the role of the normal breast microenvironment on breast cancer cell tumorigenicity, we examined whether extracellular matrix molecules (ECM) derived from premenopausal African-American (AA) or Caucasian-American (CAU) breast tissue would affect the tumorigenicity of cancer cells <it>in vitro </it>and <it>in vivo</it>. We chose these two populations because of the well documented predisposition of AA women to develop aggressive, highly metastatic breast cancer compared to CAU women.</p> <p>Methods</p> <p>The effects of primary breast fibroblasts on tumorigenicity were analyzed via real-time PCR arrays and mouse xenograft models. Whole breast ECM was isolated, analyzed via zymography, and its effects on breast cancer cell aggressiveness were tested <it>in vitro </it>via soft agar and invasion assays, and <it>in vivo </it>via xenograft models. Breast ECM and hormone metabolites were analyzed via mass spectrometry.</p> <p>Results</p> <p>Mouse mammary glands humanized with premenopausal CAU fibroblasts and injected with primary breast cancer cells developed significantly larger tumors compared to AA humanized glands. Examination of 164 ECM molecules and cytokines from CAU-derived fibroblasts demonstrated a differentially regulated set of ECM proteins and increased cytokine expression. Whole breast ECM was isolated; invasion and soft agar assays demonstrated that estrogen receptor (ER)^-, progesterone receptor (PR)/PR^-cells were significantly more aggressive when in contact with AA ECM, as were ER⁺/PR⁺cells with CAU ECM. Using zymography, protease activity was comparatively upregulated in CAU ECM. In xenograft models, CAU ECM significantly increased the tumorigenicity of ER⁺/PR⁺cells and enhanced metastases. Mass spectrometry analysis of ECM proteins showed that only 1,759 of approximately 8,000 identified were in common. In the AA dataset, proteins associated with breast cancer were primarily related to tumorigenesis/neoplasia, while CAU unique proteins were involved with growth/metastasis. Using a novel mass spectrometry method, 17 biologically active hormones were measured; estradiol, estriol and 2-methoxyestrone were significantly higher in CAU breast tissue.</p> <p>Conclusions</p> <p>This study details normal premenopausal breast tissue composition, delineates potential mechanisms for breast cancer development, and provides data for further investigation into the role of the microenvironment in cancer disparities.</p

Systematic review and meta-analysis of clinical trials examining the effect of hyperbaric oxygen therapy in people with diabetes-related lower limb ulcers

Aim: To examine the efficacy of hyperbaric oxygen therapy in healing diabetes-related lower limb ulcers through a meta-analysis of randomized clinical trials. Methods: A literature search was conducted to identify appropriate clinical trials. Inclusion required randomized study design and reporting of the proportion of diabetes-related lower limb ulcers that healed. A meta-analysis was performed to examine the effect of hyperbaric oxygen therapy on ulcer healing. The secondary outcomes were minor and major amputations. Results: Nine randomized trials involving 585 participants were included. People allocated to hyperbaric oxygen therapy were more likely to have complete ulcer healing (relative risk 1.95, 95% CI 1.51–2.52; P<0.001), and less likely to require major (relative risk 0.54, 95% CI 0.36–0.81; P=0.003) or minor (relative risk 0.68, 95% CI 0.48–0.98; P=0.040) amputations than control groups. Sensitivity analyses suggested the findings were dependent on the inclusion of one trial. Adverse events included ear barotrauma and a seizure. Many of the trials were noted to have methodological weaknesses including absence of blinding of outcome assessors, lack of a justifiable sample size calculation and limited follow-up. Conclusions: This meta-analysis suggests hyperbaric oxygen therapy improves the healing of diabetes-related lower limb ulcers and reduces the requirement for amputation. Confidence in these results is limited by significant design weaknesses of previous trials and inconsistent findings. A more rigorous assessment of the efficacy of hyperbaric the efficacy of hyperbaric oxygen therapy is needed