mTOR – ключевой сигнальный белок сигнального пути PI3K/Akt, блокада которого приводит к подавлению пролиферации клеток и повышает чувствительность опухолевой клетки к лекарственному и лучевому воздействию. Доля активирующих мутаций PI3K при раке молочной железы (РМЖ) достигает 40%, что свидетельствует о ее важности в канцерогенезе при данной патологии. Активация mTOR сигнального пути – ключевой адаптивный механизм развития резистентности к эндокринной терапии при РМЖ, а использование ингибиторов mTOR может восстанавливать чувствительность опухоли к эндокринной терапии. Эверолимус – избирательный ингибитор mTOR, нарушающий трансляцию кодируемых мРНК основных протеинов, участвующих в регуляции клеточного цикла, гликолиза и адаптации клеток к гипоксии. Эффективность и безопасность эверолимуса в лечении гормонопозитивного РМЖ изучена в крупных рандомизированных исследованиях. В исследовании TAMRAD показана высокая эффективность и хорошая переносимость комбинации тамоксифена с эверолимусом у пациенток с ER(+)HER2(-) РМЖ, резистентным к терапии ингибиторами ароматазы: клиническая эффективность комбинации значительно превысила таковую при монотерапии тамоксифеном (61% vs 42%), особенно у пациенток с вторичной гормонорезистентностью (74% vs 48%). Использование эверолимуса существенно увеличило время до прогрессирования болезни – 8,6 мес vs 4,5 мес и снизило риск дальнейшего прогрессирования на 46% для всех больных и на 54% – для пациенток с вторичной резистентностью к ингибиторам ароматазы. Исследование BOLERO-2 показало высокую эффективность использования комбинации эверолимуса и экземестана при ER(+)HER2(-) распространенном РМЖ, у пациенток в постменопаузе, предлеченных ингибиторами ароматазы. Показано убедительное увеличение медианы безрецидивной выживаемости (БРВ) при использовании эверолимуса. Важным является факт снижения риска дальнейшего прогрессирования распространенного процесса у пациенток, принимающих эверолимус: с висцеральными метастазами на 53%, без висцеральных метастазов на 59%. Исследование J.Baselga и соавт. показало еще одно перспективное направление использования эверолимуса – неоадъювантную терапию гормонопозитивного РМЖ. Препарат показал высокую клиническую эффективность, подтвержденную данными морфологического исследования опухоли.
Ключевые слова: сигнальный путь PI3K/Akt, резистентность к эндокринной терапии при РМЖ, ингибиторы mTOR, эверолимус, распространенный гормонопозитивный РМЖ.
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mTOR is a key signaling protein in the PI3K/Akt signaling pathway whose blockage results in inhibition of cell proliferation and enhances the susceptibility of a tumor cell to drugs and radiation. The proportion of P13K mutations in breast cancer (BC) amounts up to 40%, which is suggestive of its importance in carcinogenesis in this pathology. Activation of the mTOR signaling pathway is a key adaptive mechanism for the development of resistance to endocrine therapy in BC and the use of mTOR inhibitors may restore tumor susceptibility to endocrine therapy. Everolimus is a selective mTOR inhibitor that impairs translation of the mRNAs coding for the major proteins involved in the regulation of a cellular cycle, glycolysis, and hypoxic adaptation. The efficacy and safety of everolimus in the treatment of hormone-positive BC have been investigated in large-scale randomized trials. The TAMRAD trial has shown that a combination of tamoxifen and everolimus is highly effective and well tolerated in patients with ER(+)HER2(-) BC-resistant to therapy with aromatase inhibitors: the clinical efficacy of the combination far exceeds that of tamoxifen monotherapy (61% vs 42%) particularly in patients with secondary hormone resistance (74% vs 48%). The use of everolimus considerably increased time to disease progression (8,6 months vs 4,5 months) and reduced the risk of further progression by 46% for all the patients and by 54% for patients with secondary resistance to aromatase inhibitors. The BOLERO-2 trial has indicated that a combination of everolimus and exemestane is highly effective in disseminated ER(+)HER2(-) BC, in postmenopausal patients pretreated with aromatase inhibitors. The use of everolimus showed a convincing increase in median relapse-free survival. The fact that the risk of further progression of the disseminated process reduces in everolimus-treated patients with and without visceral metastases by 53 and 59%, respectively, is of importance. The investigation conducted by J.Baselga et al demonstrated another promising area for the use of everolimus – neoadjuvant therapy for hormone-positive BC. The drug displayed a high clinical efficacy as evidenced by a tumor morphological study.
Key words: PI3K/Akt signaling pathway, resistance to endocrine therapy in breast cancer, mTOR inhibitors, everolimus, disseminated hormone-positive breast cancer.
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Авторы
И.В.Колядина, Н.П.Макаренко, И.В.Поддубная
Кафедра онкологии ГБОУ ДПО РМАПО Минздрава РФ, Москва