Metadata supporting data files on the impact of a hypericin PDT–tamoxifen hybrid therapy on MCF7 and MDA-MB-231 resistances

This metadata record describes the files supporting the related publication: Simultaneous defeat of MCF7 and MDA-MB-231 resistances by a hypericin PDT–tamoxifen hybrid therapy.

The related study reports the development of a synergistic combinatorial cancer treatment HYPERTAM, which uses tamoxifen (TAM) chemotherapy and hypericin photodynamic therapy (HYP-PDT). The study addresses the challenge of the lack of homogeneity in lesions where different cell components respond differently to treatments, a limiting factor for monotherapies.

Study design and methods

The study involved a proof of principle investigation of the efficacy of HYPERTAM in human cell culture and an in vivo animal study using NOD SCID-γ (NSG) mice.

The efficacy of HYPERTAM on cell lines was investigated using clonogenic assay and flow cytometric assay to elucidate the prevalent death mechanisms in the treatment groups (4-OHT, HYP-PDT and 4-OHT+HYP-PDT). The extent of lipid peroxidation in the various treatment groups in the two cell lines was then investigated, followed by metabolic analyses after HYPERTAM treatment with oxygen consumption rate (OCR) reflecting the respiratory activity of the cells, and extracellular (media) acidification rate reflecting the cell glycolytic activity.

Following the proof of principle investigation in cell cultures, the hypothesis that HYP-PDT exacerbates the cytotoxic action of tamoxifen by irreversibly inhibiting mitochondrial complex III²⁵ was investigated in an in-vivo pilot study. This used immunocompromised NSG mice bearing MCF7 and MDA-MB-231 xenografted tumors. Survival rates were based on the endpoints of tumor volume being ≤1000 mm³.

Sample size

Each mouse group contained at least 5 mice while the groups of particular interest contained either 6 or 7 mice. See related article for detailed group breakdown.