title: Trastuzumab and docetaxel in a preclinical organotypic breast cancer model using tissue slices from mammary fat pad: Translational relevance.
abstract: With the ever-increasing number of drugs approved to treat cancers, selection of the optimal treatment regimen for an individual patient is challenging. Breast cancer complexity requires novel predictive methods and tools. In the present study, we set up experimental conditions to obtain an 'ex vivo' organotypic culture from xenotransplanted mice aiming at recapitulating the human clinical condition. The effect of trastuzumab (large biological molecule) and docetaxel (small chemical entity) was subsequently investigated on this organotypic model and compared with in vivo and in vitro activity on tumor cells. Tissue slices of 200 µm were obtained from mammary fat pad of SCID mice xenotransplanted with human MCF-7 breast cancer cells. Viability and proliferation were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) colorimetric assay and Ki-67 immunohistochemistry,and apoptosis by cleaved caspase-3 immunohistochemistry. In vivo antitumor activity of trastuzumab and docetaxel was determined by caliper measurement of tumor volume and Ki-67 expression on explanted masses by immunohistochemistry. A Teflon support and normoxia were necessary experimental conditions to obtain high viability of excised breast cancer infiltrated mammary fat pad slices upon 48 h cultivation, as shown by MTT proliferation assay, and Ki-67 expression. Breast cancer tissue slices treated for 48 h with trastuzumab or docetaxel showed a significant dose‑dependent reduction of viability by MTT assay. Consistently, both drugs down-modulated Ki-67 and increased cleaved caspase-3. Tumor masses collected from docetaxel- or trastuzumab‑treated mice showed a similar reduction of proliferation markers. By contrast, MCF-7 cell cultures were significantly inhibited by docetaxel but not by trastuzumab. Tumor tissue slices represent a more predictive experimental cancer model compared to cell cultures for both small and large molecule antitumor efficacy. This observation supports the relevance of microenvironment in the overall tumor biology and response to therapeutics.
authors.affiliation: Biotechnology, Research and Development, Sigma-Tau Industrie Farmaceutiche Riunite S.p.A., I-00040 Pomezia, Italy.
authors.forename: Loredana
authors.initials: L
authors.lastname: Vesci
authors.affiliation: Tissue Macro Array Lab, University of Tor Vergata, I-00133 Rome, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Carollo
authors.affiliation: Takis Biotechnology, Castel Romano, I-00128 Rome, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Roscilli
authors.affiliation: Takis Biotechnology, Castel Romano, I-00128 Rome, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Aurisicchio
authors.affiliation: Takis Biotechnology, Castel Romano, I-00128 Rome, Italy.
authors.forename: Fabiana Fosca
authors.initials: FF
authors.lastname: Ferrara
authors.affiliation: Tissue Macro Array Lab, University of Tor Vergata, I-00133 Rome, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Spagnoli
authors.affiliation: Biotechnology, Research and Development, Sigma-Tau Industrie Farmaceutiche Riunite S.p.A., I-00040 Pomezia, Italy.
authors.forename: Rita
authors.initials: R
authors.lastname: De Santis
mesh_terms: D000273:Adipose Tissue; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D000077143:Docetaxel; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D061986:MCF-7 Cells; D008325:Mammary Neoplasms, Experimental / Q000188:drug therapy*; D051379:Mice; D016513:Mice, SCID; D009924:Organ Culture Techniques / Q000379:methods*; D043823:Taxoids / Q000494:pharmacology*; D000068878:Trastuzumab / Q000494:pharmacology*; D023041:Xenograft Model Antitumor Assays / Q000379:methods*
chemical_list: D000970:Antineoplastic Agents; D043823:Taxoids; D000077143:Docetaxel; D000068878:Trastuzumab