N. Margarese

Analysis of molecular mechanisms and anti-tumoural effects of zoledronic acid in breast cancer cells

Zoledronic acid (ZOL) is the most potent nitrogen‐containing bisphosphonate (N‐BPs) that strongly binds to bone mineral and acts as a powerful inhibitor of bone resorption, already clinically available for the treatment of patients with osteolytic metastases. Recent data also suggest that ZOL, used in breast cancer, may provide more than just supportive care modifying the course of the disease, though the possible molecular mechanism of action is still unclear.As breast cancer is one of the primary tumours with high propensity to metastasize to the bone, we investigated, for the first time, differential gene expression profile on Michigan Cancer Foundation‐7 (MCF‐7) breast cancer cells treated with low doses of ZOL (10 μM). Microarrays analysis was used to identify, describe and summarize evidence regarding the molecular basis of actions of ZOL and of their possible direct anti‐tumour effects. We validated gene expression results of specific transcripts involved in major cellular process by Real Time and Western Blot analysis and we observed inhibition of proliferation and migration through 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) and Matrigel assay. We then focused on changes in the cytoskeletal components as fibronectin 1 (FN1), actin, and anti angiogenic compounds as transforming growth factor‐β1 (TGF‐β1) and thrombospondin 1 (THBS1). The up‐regulation of these products may have an important role in inhibiting proliferation, invasion and angiogenesis mediated by ZOL.

The Clinical Significance of Unknown Sequence Variants in BRCA Genes

Germline mutations in BRCA1/2 genes are responsible for a large proportion of hereditary breast and/or ovarian cancers. Many highly penetrant predisposition alleles have been identified and include frameshift or nonsense mutations that lead to the translation of a truncated protein. Other alleles contain missense mutations, which result in amino acid substitution and intronic variants with splicing effect. The discovery of variants of uncertain/unclassified significance (VUS) is a result that can complicate rather than improve the risk assessment process. VUSs are mainly missense mutations, but also include a number of intronic variants and in-frame deletions and insertions. Over 2,000 unique BRCA1 and BRCA2 missense variants have been identified, located throughout the whole gene (Breast Cancer Information Core Database (BIC database)). Up to 10–20% of the BRCA tests report the identification of a variant of uncertain significance. There are many methods to discriminate deleterious/high-risk from neutral/low-risk unclassified variants (i.e., analysis of the cosegregation in families of the VUS, measure of the influence of the VUSs on the wild-type protein activity, comparison of sequence conservation across multiple species), but only an integrated analysis of these methods can contribute to a real interpretation of the functional and clinical role of the discussed variants. The aim of our manuscript is to review the studies on BRCA VUS in order to clarify their clinical relevance.