Acyl-CoA synthetase-4 mediates radioresistance of breast cancer cells by regulating FOXM1.

The development of radioresistance during radiotherapy is a major cause of tumor recurrence and metastasis. To provide new insights of the mechanisms underlying radioresistance, we established radioresistant cell lines derived from two different subtypes of breast cancer cells, HER2-positive SK-BR-3 and ER-positive MCF-7 breast cancer cells, by exposing cells to 48 ~ 70 Gy of radiation delivered at 4-5 Gy twice weekly over 9 ~ 10 months. The established radioresistant SK-BR-3 (SR) and MCF-7 (MR) cells were resistant not only to a single dose of radiation (2 Gy or 4 Gy) but also to fractionated radiation delivered at 2 Gy/day for 5 days.

Evaluation of Radiotherapy-Induced Systemic Antitumor Effects in Mice Bearing 4T1 Mouse Breast Cancer Cells.

Recently, several clinical studies have reported that combination treatments of radiation therapy (RT) and immunotherapy in patients with multiple lesions can improve tumor regression at a distance from the irradiated site, known as the abscopal effect. However, when RT and immunotherapy are concurrently applied, it is hard to distinguish the pure systemic effects of RT from those of the immunotherapy drug. In this preclinical study, the authors investigated the systemic antitumor effects of RT alone according to fraction dose size and splitting schedules.

Inhibition of TPA‑induced metastatic potential by morin hydrate in MCF‑7 human breast cancer cells via the Akt/GSK‑3β/c‑Fos signaling pathway.

Plant flavonoid 2',3,4',5,7‑pentahydroxyflavone (morin hydrate), isolated from the family Moraceae (Morus alba L.), is known to have anti‑inflammatory and anticancer effects. However, its pharmaceutical effects on metastasis have not been fully elucidated to date.

Determination of the optimal time for tamoxifen treatment in combination with radiotherapy.

Although radiotherapy and tamoxifen have been extensively used to treat estrogen receptor α (ERα)-positive breast cancers, it is still questionable when tamoxifen should be started to maximize clinical benefits in combination with radiotherapy. Generally, clinician's opinion and experience are major determinants in scheduling concurrent or sequential tamoxifen and radiotherapy. Thus, we attempted to determine an optimal time to start tamoxifen treatment by analyzing tamoxifen responses at different times after irradiating MCF-7 cells to cumulative doses of 10 or 20-30 Gy.