Action of tamoxifen on the reproductive organs of guinea pigs

Murav'eva, N I; Kuz'mina, Z V; Smirnova, K D; Es, Gershteĭn; Ird, E. A.; Fuks, M A

doi:10.1007/bf00838918

Cited by 2 publications

(2 citation statements)

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“…The oestrogen receptor α status of breast cancer is a predictive parameter of the response to hormone therapy [18,19]. Developed in the 60s, tamoxifen (2-[4-[(Z)-1,2-diphenylbut-1-enyl]phenoxy]-N,N-dimethylethanamine), an antihormonal agent belonging to SERMs, has become widespread [20][21][22][23]. These days, tamoxifen remains the "gold standard" for hormonal therapy.…”

Section: Introductionmentioning

confidence: 99%

Towards Unravelling the Role of ERα-Targeting miRNAs in the Exosome-Mediated Transferring of the Hormone Resistance

et al. 2021

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Hormone therapy is one of the most effective breast cancer treatments, however, its application is limited by the progression of hormonal resistance, both primary or acquired. The development of hormonal resistance is caused either by an irreversible block of hormonal signalling (suppression of the activity or synthesis of hormone receptors), or by activation of oestrogen-independent signalling pathways. Recently the effect of exosome-mediated intercellular transfer of hormonal resistance was revealed, however, the molecular mechanism of this effect is still unknown. Here, the role of exosomal miRNAs (microRNAs) in the transferring of hormonal resistance in breast cancer cells has been studied. The methods used in the work include extraction, purification and RNAseq of miRNAs, transfection of miRNA mimetics, immunoblotting, reporter analysis and the MTT test. Using MCF7 breast cancer cells and MCF7/T tamoxifen-resistant sub-line, we have found that some miRNAs, suppressors of oestrogen receptor signalling, are overexpressed in the exosomes of the resistant breast cancer cells. The multiple (but not single) transfection of one of the identified miRNA, miR-181a-2, into oestrogen-dependent MCF7 cells induced the irreversible tamoxifen resistance associated with the continuous block of the oestrogen receptor signalling and the activation of PI3K/Akt pathway. We suppose that the miRNAs-ERα suppressors may act as trigger agents inducing the block of oestrogen receptor signalling and breast cancer cell transition to an aggressive oestrogen-independent state.

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Section: Introductionmentioning

confidence: 99%

Towards Unravelling the Role of ERα-Targeting miRNAs in the Exosome-Mediated Transferring of the Hormone Resistance

et al. 2021

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“…He was able to induce serious aggressive cancers in about 12% of rats (Clorfene-Casten, 1996). Murav'eva et al, (1982) studied the activity of tamoxifen on the sex organs of guinea pigs for long-term administration of tamoxifen (3-5 months) in a dose of 0.4 mg/kg to guinea-pigs with estrogen-induced benign uterine tumors and found out that the drug had no toxic effects on the animals. According to their report, tamoxifen caused no definite differences in the ovarian mass: however, 40% of the guinea-pigs showed ovulation inhibition.…”

Section: Introductionmentioning

confidence: 99%

Effect of Tamoxifen on the histomorphological and biochemical components of the liver of Guinea Pigs

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et al. 2014

Afr. J. Cell. Path

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Aim: Tamoxifen, once praised for its importance in preventing breast cancer recurrence, is now implicated in dangerous side-effects. The authors are not aware of studies on the effect of tamoxifen on the histomorphological and biochemical components of the liver of guinea pig, hence the present one. Methods: Thirty guinea pigs weighing between 650g and 700g were assigned randomly into 6 groups of five and were separately given 0.70 and 7.0mg/kg body weight (b.w) tamoxifen for 2 and 4 weeks. Liver function tests and conventional tissue processing haematoxylin and eosin staining method were used in the study. Results: The results showed a significant loss in body weight (p<0.05) of the guinea pigs administered with low and high doses of the tamoxifen for 4 weeks when compared with the controls. The mean serum levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total bilirubin and conjugated bilirubin increased significantly than the controls in high dose groups exposed for 2 weeks and 4 weeks respectively (p<0.05). Similarly, histomorphological changes such as enlargement and sclerotic condition of central vein, enlargement and non-hexagonal radiating arrangement of sinusoids were observed in the liver of guinea pigs in the high dose tamoxifen

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Action of tamoxifen on the reproductive organs of guinea pigs

Cited by 2 publications

References 6 publications

Towards Unravelling the Role of ERα-Targeting miRNAs in the Exosome-Mediated Transferring of the Hormone Resistance

Towards Unravelling the Role of ERα-Targeting miRNAs in the Exosome-Mediated Transferring of the Hormone Resistance

Effect of Tamoxifen on the histomorphological and biochemical components of the liver of Guinea Pigs

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