Matrix metalloproteinases (MMPs) have been suggested as therapeutic targets in cancer treatment, but broad-spectrum MMP inhibitors have failed in clinical trials. Recent data suggest that several MMPs including MMP-9 exert both pro- and antitumorigenic properties. This is also the case of the natural inhibitors of MMPs, tissue inhibitor of metalloproteinases (TIMPs). The inhibitor of MMP-9 is TIMP-1, and high levels of this enzyme have been associated with decreased survival in breast cancer. Inflammation is one hallmark of cancer progression, and MMPs/TIMPs may be involved in the local immune regulation. We investigated the role of MMP-9/TIMP-1 in regulating innate antitumor immunity in breast cancer. Breast cancers were established in nude mice and treated with intratumoral injections of adenoviruses carrying the human TIMP-1 or MMP-9 gene (AdMMP-9). In vivo microdialysis for sampling of cancer cell–derived (human) and stroma-derived (murine) proteins, immunostainings, as well as cell cultures were performed. We report a dose-dependent decrease of tumor growth and angiogenesis after AdMMP-9 treatment. In addition to increased generation of endostatin, AdMMP-9 promoted an antitumor immune response by inducing massive neutrophil infiltration. Neutrophil depletion prior to gene transfer abolished the therapeutic effects of AdMMP-9. Additionally, AdMMP-9 activated tumor-infiltrating macrophages into a tumor-inhibiting phenotype both in vivo and in vitro. AdMMP-9 also inhibited tumor growth in immune-competent mice bearing breast cancers. Adenoviruses carrying the human TIMP-1 gene had no effect on tumor growth or the immune response. Our novel data identify MMP-9 as a potent player in modulating the innate immune response into antitumor activities.

The results suggest that the RAD51 135G>C polymorphism predicts CMF chemotherapy effect in early breast cancer.

Abstract. The purpose was to study the prognostic and predictive roles of DNA protein kinase catalytic subunit (DNA-PKcs), Ku70/80 and p53 for the effect of radiotherapy in breast cancer patients. Protein expressions of Ku70/80, DNA-PKcs and p53 were examined using immunohistochemistry in tumours from 224 breast cancer patients, who were randomised to receive post-operative radiotherapy or adjuvant chemotherapy (cyclophosphamide, methotrexate, 5-fluorouracil). One hundred and twenty-nine (60%) of the tumours had low expression of Ku70/80, 122 (57%) had low expression of DNA-PKcs and 65 (30%) had altered p53 expression. None of the proteins were indicative to the prognosis of local recurrence-free survival. Even though the expression of Ku70/80 and DNA-PKcs correlated well, they were not associated with treatment outcome in the same way. Low expression of Ku70/80 predicted good effect of radiotherapy (RR=0.31, 95% CI 0.13-0.76, p=0.01). In contrast, the greatest benefit of radiotherapy over chemotherapy was seen in patients with high DNA-PKcs expression (RR=0.25, 95% CI 0.07-0.84, p=0.02). Altered p53 expression predicted poor response to radiotherapy. We believe that the results reflect the different roles of DNA-PKcs and Ku70/80 in repair and cell death regulation after DNA damage. These differences could be of importance when developing drugs that target DNA repair.