Effect of Tamoxifen and Estrogen Treatment on the Radiosensitivity of MCF-7 Breast Cancer Cells

Böhning, K.; Busch, M.; Rave-Fränk, M.; Dühmke, Eckhart

doi:10.1159/000218846

Cited by 8 publications

(12 citation statements)

References 12 publications

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“…These experimental observations have been confirmed by Villalobos et al (1996) and by Böhning et al (1996), using similar experimental conditions (Table 3). Böhning et al (1996) showed that the duration of tamoxifen incubation prior to irradiation (24-96 h) influenced the experimental results: the longer the incubation period, the lower the radiation sensitivity of the cells.…”

Section: In Vitro Experiments On the Interaction Of Estrogens Anti-esupporting

confidence: 75%

“…Böhning et al (1996) showed that the duration of tamoxifen incubation prior to irradiation (24-96 h) influenced the experimental results: the longer the incubation period, the lower the radiation sensitivity of the cells. Villalobos et al (1996) showed that estrogen withdrawal decreased radiosensitivity in ERpositive MCF-7 BUS cells that had intact p53.…”

Section: In Vitro Experiments On the Interaction Of Estrogens Anti-ementioning

confidence: 99%

“…It should be kept in mind that in vitro conditions such as the presence of phenol red or fetal bovine serum might mimic estrogenic activity on the cells. Some studies have been performed in the presence of one or both of these factors (Wazer et al 1989, Böhning et al 1996, Paulsen et al 1996, Newton et al 1998, others have used charcoal-stripped calf serum and phenol-free media (Sarkaria et al 1994, Villalobos et al 1995. The in vitro action of tamoxifen is dependent on the presence of estradiol in the medium.…”

mentioning

confidence: 99%

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Interactions between radiation and endocrine therapy in breast cancer.

Schmidberger¹,

Hermann²,

Hess³

et al. 2003

Endocrine-Related Cancer

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Adjuvant radiotherapy and adjuvant endocrine therapy are commonly given to patients with invasive breast cancer or with ductal carcinoma in situ (DCIS). Although both therapies have been well established through a number of randomized studies, little is known about a possible interaction of both treatment modalities if they are given simultaneously. A number of in vitro studies have indicated that tamoxifen treatment might reduce the intrinsic radiosensitivity of MCF-7 breast cancer cells. Conversely, estradiol treatment increases the intrinsic radiosensitivity of MCF-7 cells. In one available animal study, an antagonistic effect of tamoxifen and ionizing radiation (XRT) could not be observed. Retrospective analyses of randomized clinical studies have not indicated an antagonistic effect of tamoxifen on the effectiveness of XRT, since local control has been consistently higher when XRT was combined with tamoxifen, compared with treatment with XRT alone, regardless of whether tamoxifen was started simultaneously with radiotherapy or after completion of radiotherapy. Currently there are no clinical data available that would suggest an adverse effect of adjuvant tamoxifen treatment started prior to or simultaneously with radiotherapy in breast cancer or DCIS. However, since an antagonistic effect of tamoxifen and simultaneous chemotherapy has been reported recently, the issue of simultaneous versus sequential radiation and tamoxifen treatment in breast cancer should be addressed in further studies.

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Section: In Vitro Experiments On the Interaction Of Estrogens Anti-esupporting

confidence: 75%

Section: In Vitro Experiments On the Interaction Of Estrogens Anti-ementioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Interactions between radiation and endocrine therapy in breast cancer.

Schmidberger¹,

Hermann²,

Hess³

et al. 2003

Endocrine-Related Cancer

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show abstract

“…In contrast, incubation of the MCF-7 cells with 17β-estradiol (E2) increased the radiosensitivity of the cells. Similar results have been reported by others [3][4][5], using similar experimental conditions (table 1). Tamoxifen treatment altered the survival of the irradiated MCF-7 cells by widening the shoulder portion of the survival curve, pointing towards an increased repair of radiation-induced potentially lethal DNA damage.…”

Section: In Vitro Experiments On the Interaction Of Estrogens Antiessupporting

confidence: 92%

Combination of Anti-Estrogenic Therapy with Radiation in Breast Cancer: Simultaneous or Sequential Treatment?

Schmidberger

Hermann²,

Hess³

et al. 2005

Oncol Res Treat

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Adjuvant radiotherapy and adjuvant endocrine therapy are commonly given to patients with invasive breast cancer or with ductal carcinoma in situ (DCIS). Although both therapies have been well established through a number of randomized studies, little is known about a possible interaction of both treatment modalities if they are given simultaneously. A number of in vitro studies indicated that tamoxifen treatment might reduce the intrinsic radiosensitivity of MCF-7 breast cancer cells. Conversely, estradiol treatment increased the intrinsic radiosensitivity of MCF-7 cells. This phenomenon has not been found in clinical studies. Retrospective analyses of prospectively randomized clinical studies did not indicate an antagonistic effect of tamoxifen on the effectiveness of ionizing radiation (XRT), since local control has been consistently higher when XRT was combined with tamoxifen, compared to treatment with XRT alone, regardless of whether tamoxifen was started simultaneously with radiotherapy or after completion of radiotherapy. Currently there are no clinical data available that would suggest an adverse effect of adjuvant tamoxifen treatment started prior to or simultaneously with radiotherapy in breast cancer or DCIS. However, since an antagonistic effect of tamoxifen and simulteneous chemotherapy has been reported recently, the issue of simultaneous

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“…Diese erhöhte Resistenz gegenüber Bestrahlung wurde auf eine erhöhte Blockade der Zellen in der G1-Phase zurückgeführt [76]. Dies wird durch weitere Untersuchungen unterstützt, die eine Zunahme der Strahlenresistenz mit dem Zeitraum (24-96 h) der TAM-Vorbehandlung beschrieben [11,72,73].…”

Section: Wirkung Am Tumor Experimentelle Untersuchungenunclassified