BACKGROUND: Resistance to chemotherapy is a major problem in the treatment of patients with triple-negative breast cancer (TNBC). Preclinical data suggest that TNBC is dependent on proteasomes; however, clinical observations indicate that the efficacy of proteasome inhibitors in TNBC may be limited, suggesting the need for combination therapies. METHODS: We compared bortezomib and carfilzomib and their combinations with nelfinavir and lopinavir in TNBC cell lines and primary cells with regard to their cytotoxic activity, functional proteasome inhibition, and induction of the unfolded protein response (UPR). Furthermore, we evaluated the involvement of sXBP1, ABCB1, and ABCG2 in the cytotoxic activity of drug combinations. RESULTS: Carfilzomib, via proteasome β5 + β2 inhibition, is more cytotoxic in TNBC than bortezomib, which inhibits β5 + β1 proteasome subunits. The cytotoxicity of carfilzomib was significantly potentiated by nelfinavir or lopinavir. Carfilzomib with lopinavir induced endoplasmic reticulum stress and pro-apoptotic UPR through the accumulation of excess proteasomal substrate protein in TNBC in vitro. Moreover, lopinavir increased the intracellular availability of carfilzomib by inhibiting carfilzomib export from cells that express high levels and activity of ABCB1, but not ABCG2. CONCLUSION: Proteasome inhibition by carfilzomib combined with nelfinavir/lopinavir represents a potential treatment option for TNBC, warranting further investigation.
- MeSH
- ABC transportér z rodiny G, člen 2 * metabolismus antagonisté a inhibitory MeSH
- apoptóza účinky léků MeSH
- bortezomib * farmakologie MeSH
- inhibitory HIV-proteasy * farmakologie MeSH
- inhibitory proteasomu farmakologie MeSH
- lidé MeSH
- Lopinavir * farmakologie MeSH
- nádorové buněčné linie MeSH
- nádorové proteiny antagonisté a inhibitory metabolismus MeSH
- nelfinavir * farmakologie MeSH
- oligopeptidy * farmakologie MeSH
- P-glykoproteiny metabolismus MeSH
- protokoly protinádorové kombinované chemoterapie farmakologie MeSH
- signální dráha UPR * účinky léků MeSH
- stres endoplazmatického retikula účinky léků MeSH
- synergismus léků * MeSH
- triple-negativní karcinom prsu * farmakoterapie patologie MeSH
- XBP1 metabolismus genetika MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUND/AIMS: Melatonin is a hormone transferring information about duration of darkness to the organism and is known to modulate several signaling pathways in the cells, e.g. generation of endoplasmic reticulum stress, oxidative status of the cells, etc. Melatonin has been shown to exert antiproliferative and cytotoxic effects on various human cancers. We proposed that this hormone can differently affect tumour cells and healthy cells. METHODS: We compared the effect of 24 h melatonin treatment on calcium transport (by fluorescent probes FLUO-3AM and Rhod-5N), ER stress (determined as changes in the expression of CHOP, XBP1 and fluorescently, using Thioflavin T), ROS formation (by CellROX® Green/Orange Reagent) and apoptosis induction (by Annexin-V-FLUOS/propidiumiodide) in two tumour cell lines - ovarian cancer cell line A2780 and stable cell line DLD1 derived from colorectal carcinoma, with non-tumour endothelial cell line EA.hy926. RESULTS: Melatonin increased apoptosis in both tumour cell lines more than twice, while in EA.hy926 cells the apoptosis was increased only by 30%. As determined by silencing with appropriate siRNAs, both, type 1 sodium/calcium exchanger and type 1 IP3 receptor are involved in the apoptosis induction. Antioxidant properties of melatonin were significantly increased in EA.hy926 cells, while in tumour cell lines this effect was much weaker. CONCLUSION: Taken together, melatonin has different antioxidative effects on tumour cells compared to non-tumour ones; it also differs in the ability to induce apoptosis through the type 1 sodium/calcium exchanger, and type 1 IP3 receptor. Different targeting of calcium transport systems in tumour and normal, non-tumour cells is suggested as a key mechanism how melatonin can exert its anticancer effects. Therefore, it might have a potential as a novel therapeutic implication in cancer treatment.
- MeSH
- apoptóza účinky léků MeSH
- cytosol metabolismus MeSH
- fluorescenční mikroskopie MeSH
- inositol-1,4,5-trisfosfát - receptory antagonisté a inhibitory genetika MeSH
- lidé MeSH
- malá interferující RNA metabolismus MeSH
- melatonin toxicita MeSH
- nádorové buněčné linie MeSH
- pumpa pro výměnu sodíku a vápníku antagonisté a inhibitory genetika metabolismus MeSH
- reaktivní formy kyslíku metabolismus MeSH
- RNA interference MeSH
- stres endoplazmatického retikula účinky léků MeSH
- transkripční faktor CHOP genetika metabolismus MeSH
- vápník metabolismus MeSH
- XBP1 genetika metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
