Immunofluorescence can assess the efficacy of mTOR pathway therapeutic agent Everolimus in breast cancer models

Abstract

When breast cancer patients start to exhibit resistance to hormonal therapy or chemotherapy, the mTOR inhibitor everolimus can be considered as an alternative therapeutic agent. Everolimus can deregulate the PI3K/AKT/mTOR pathway and affect a range of cellular functions. In some patients, the agent does not exhibit the desired efficacy and, even worse, not without the associated side effects. This study assessed the use of immunofluorescence (IF) as a modality to fill this unmet need of predicting the efficacy of everolimus prior to administration. Cell viability and MTT assays based on IF intensities of pho-4EBP1 Thr37/46 and pho-S6K1 Ser424 on breast cancer cells (Hs578T, MCF7, BT474, MDA-MB-231) and patient-derived cell culture from metastatic sites (ABC-82T and ABC-16TX1) were interrogated. Results show that independent pho-4EBP1 Thr37/46 and pho-S6K1 Ser424 IF expressions can classify data into different groups: everolimus sensitive and resistant. The combined IF baseline intensity of these proteins is predictive of the efficacy of everolimus, and their intensities change dynamically when cells are resistant to everolimus. Furthermore, mTOR resistance is not only consequence of the AKT/mTOR pathway but also through the LKB1 or MAPK/ERK pathway. The LKB1 and pho-GSK3β may also be potential predictive markers for everolimus.

Protective Effect of Tangeretin and 5-Hydroxy-6,7,8,3′,4′-Pentamethoxyflavone on Collagen-Induced Arthritis by Inhibiting Autophagy via Activation of the ROS-AKT/mTOR Signaling Pathway

“…TAN also attenuated myocardial dysfunction acting on the AKT/mTOR pathway . In this study, in the BIIC group, both the decreased level of soluble p62 and the increased ratio of LC3 II to LC3 I indicated the activation and increment of autophagy degree. , Comparing with the BIIC stimulated group, the phosphorylation level of Akt and mTOR was significantly increased with the treatment of TAN or 5-HPMF, demonstrating that TAN and 5-HPMF alleviated the autophagy level through the Akt signaling pathway, which is consistent with the results from TEM examination. Results from this study suggested that TAN or 5-HPMF down-regulated the autophagy level of articular chondrocytes and maintained the normal state of chondrocytes by increasing the phosphorylation of AKT/mTOR.…”

Improved Treatment Outcomes by Using Patient Specific Drug Combinations in Mammalian Target of Rapamycin Activated Advanced Metastatic Cancers

“…Prior attempts to identify potentially synergistic and safe anticancer drug combinations (Wang and Sorger, 2017;Sidorov et al, 2019;Zagidullin et al, 2019) as well as to predict drug efficacy via in vitro CRP of cell lines or primary tumor cellsy (Hurvitz et al, 2015;Mercatali et al, 2016;Kuo et al, 2019) reflect a consensus in favor of personalized combination regimens based on molecular and functional evidence. However, these prior reports do not have any correlation with clinical outcome data.…”

Still Living Better through Chemistry: An Update on Caloric Restriction and Caloric Restriction Mimetics as Tools to Promote Health and Lifespan

“…Everolimus binds to FKBP12, inhibiting mTORC1, and results in the downregulation of the PI3K/AKT/mTOR pathway (Figure 2A). In some human cancers, this exerts an antiproliferative effect, inhibiting migration and angiogenesis [230], parallel to CR, AAR, and rapamycin [230]. Everolimus alone, or combined with other anticancer agents, has been shown to attenuate cancer cell growth, promote increased cell death, and increase patient survival [221,224,225,231,232].…”