Bruton tyrosine kinase (BTK) inhibitor therapy induces peripheral blood lymphocytosis in chronic lymphocytic leukemia (CLL), which lasts for several months. It remains unclear whether nongenetic adaptation mechanisms exist, allowing CLL cells' survival during BTK inhibitor-induced lymphocytosis and/or playing a role in therapy resistance. We show that in approximately 70% of CLL cases, ibrutinib treatment in vivo increases Akt activity above pretherapy levels within several weeks, leading to compensatory CLL cell survival and a more prominent lymphocytosis on therapy. Ibrutinib-induced Akt phosphorylation (pAktS473) is caused by the upregulation of Forkhead box protein O1 (FoxO1) transcription factor, which induces expression of Rictor, an assembly protein for the mTORC2 protein complex that directly phosphorylates Akt at serine 473 (S473). Knockout or inhibition of FoxO1 or Rictor led to a dramatic decrease in Akt phosphorylation and growth disadvantage for malignant B cells in the presence of ibrutinib (or PI3K inhibitor idelalisib) in vitro and in vivo. The FoxO1/Rictor/pAktS473 axis represents an early nongenetic adaptation to B cell receptor (BCR) inhibitor therapy not requiring PI3Kδ or BTK kinase activity. We further demonstrate that FoxO1 can be targeted therapeutically and its inhibition induces CLL cells' apoptosis alone or in combination with BTK inhibitors (ibrutinib, acalabrutinib, pirtobrutinib) and blocks their proliferation triggered by T cell factors (CD40L, IL-4, and IL-21).

• Klíčová slova
• Drug therapy, Hematology, Leukemias, Oncology, Signal transduction,
• MeSH
• adenin * analogy a deriváty   farmakologie   MeSH
• chronická lymfatická leukemie * farmakoterapie   metabolismus   genetika   patologie   MeSH
• forkhead box protein O1 * metabolismus   genetika   MeSH
• fosforylace MeSH
• lidé MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• nádorové proteiny metabolismus   genetika   MeSH
• piperidiny * farmakologie   MeSH
• protein RICTOR * genetika   metabolismus   MeSH
• proteinkinasa BTK metabolismus   genetika   antagonisté a inhibitory   MeSH
• protoonkogenní proteiny c-akt * metabolismus   genetika   MeSH
• pyrazoly * farmakologie   MeSH
• pyrimidiny * farmakologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• adenin * MeSH
• BTK protein, human MeSH Prohlížeč
• forkhead box protein O1 * MeSH
• FOXO1 protein, human MeSH Prohlížeč
• ibrutinib MeSH Prohlížeč
• nádorové proteiny MeSH
• piperidiny * MeSH
• protein RICTOR * MeSH
• proteinkinasa BTK MeSH
• protoonkogenní proteiny c-akt * MeSH
• pyrazoly * MeSH
• pyrimidiny * MeSH

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
• Názvy látek
• ABC transportér z rodiny G, člen 2 * MeSH
• ABCB1 protein, human MeSH Prohlížeč
• ABCG2 protein, human MeSH Prohlížeč
• bortezomib * MeSH
• carfilzomib MeSH Prohlížeč
• inhibitory HIV-proteasy * MeSH
• inhibitory proteasomu MeSH
• Lopinavir * MeSH
• nádorové proteiny MeSH
• nelfinavir * MeSH
• oligopeptidy * MeSH
• P-glykoproteiny MeSH
• XBP1 protein, human MeSH Prohlížeč
• XBP1 MeSH

• MeSH
• ABC transportér z rodiny G, člen 2 genetika   MeSH
• antigeny krevních skupin * MeSH
• buněčná membrána metabolismus   MeSH
• lidé MeSH
• nádorové proteiny genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• dopisy MeSH
• Názvy látek
• ABC transportér z rodiny G, člen 2 MeSH
• ABCG2 protein, human MeSH Prohlížeč
• antigeny krevních skupin * MeSH
• nádorové proteiny MeSH

The presence of key hypoxia regulators, namely, hypoxia-inducible factor (HIF)-1α or HIF-2α, in tumors is associated with poor patient prognosis. Hypoxia massively activates several genes, including the one encoding the BCRP transporter that proffers multidrug resistance to cancer cells through the xenobiotic efflux and is a determinant of the side population (SP) associated with cancer stem-like phenotypes. As natural medicine comes to the fore, it is instinctive to look for natural agents possessing powerful features against cancer resistance. Hypericin, a pleiotropic agent found in Hypericum plants, is a good example as it is a BCRP substrate and potential inhibitor, and an SP and HIF modulator. Here, we showed that hypericin efficiently accumulated in hypoxic cancer cells, degraded HIF-1/2α, and decreased BCRP efflux together with hypoxia, thus diminishing the SP population. On the contrary, this seemingly favorable result was accompanied by the stimulated migration of this minor population that preserved the SP phenotype. Because hypoxia unexpectedly decreased the BCRP level and SP fraction, we compared the SP and non-SP proteomes and their changes under hypoxia in the A549 cell line. We identified differences among protein groups connected to the epithelial-mesenchymal transition, although major changes were related to hypoxia, as the upregulation of many proteins, including serpin E1, PLOD2 and LOXL2, that ultimately contribute to the initiation of the metastatic cascade was detected. Altogether, this study helps in clarifying the innate and hypoxia-triggered resistance of cancer cells and highlights the ambivalent role of natural agents in the biology of these cells.

• Klíčová slova
• Breast cancer resistance protein, ECM reorganization, Hypericin, Hypoxia, Proteomics, Side population,
• MeSH
• ABC transportér z rodiny G, člen 2 genetika   metabolismus   MeSH
• faktor 1 indukovatelný hypoxií - podjednotka alfa metabolismus   MeSH
• hypoxie buňky MeSH
• hypoxie MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• nádorové proteiny genetika   metabolismus   MeSH
• nádory * metabolismus   MeSH
• regulace genové exprese u nádorů MeSH
• transkripční faktory bHLH genetika   metabolismus   MeSH
• vedlejší populace buněk * patologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• ABC transportér z rodiny G, člen 2 MeSH
• faktor 1 indukovatelný hypoxií - podjednotka alfa MeSH
• hypericin MeSH Prohlížeč
• nádorové proteiny MeSH
• transkripční faktory bHLH MeSH

The nucleoside analog entecavir (ETV) is a first-line pharmacotherapy for chronic hepatitis B in adult and pediatric patients. However, due to insufficient data on placental transfer and its effects on pregnancy, ETV administration is not recommended for women after conception. To expand knowledge of safety, we focused on evaluating the contribution of nucleoside transporters (NBMPR sensitive ENTs and Na+ dependent CNTs) and efflux transporters, P-glycoprotein (ABCB1), breast cancer resistance protein (ABCG2), and multidrug resistance-associated transporter 2 (ABCC2), to the placental kinetics of ETV. We observed that NBMPR and nucleosides (adenosine and/or uridine) inhibited [3H]ETV uptake into BeWo cells, microvillous membrane vesicles, and fresh villous fragments prepared from the human term placenta, while Na+ depletion had no effect. Using a dual perfusion study in an open-circuit setup, we showed that maternal-to-fetal and fetal-to-maternal clearances of [3H]ETV in the rat term placenta were decreased by NBMPR and uridine. Net efflux ratios calculated for bidirectional transport studies performed in MDCKII cells expressing human ABCB1, ABCG2, or ABCC2 were close to the value of one. Consistently, no significant decrease in fetal perfusate was observed in the closed-circuit setup of dual perfusion studies, suggesting that active efflux does not significantly reduce maternal-to-fetal transport. In conclusion, ENTs (most likely ENT1), but not CNTs, ABCB1, ABCG2, and ABCC2, contribute significantly to the placental kinetics of ETV. Future studies should investigate the placental/fetal toxicity of ETV, the impact of drug-drug interactions on ENT1, and interindividual variability in ENT1 expression on the placental uptake and fetal exposure to ETV.

• Klíčová slova
• ATP-binding cassette transporters, Concentrative nucleoside transporters, Entecavir, Equilibrative nucleoside transporters, Placental transfer,
• MeSH
• ABC transportér z rodiny G, člen 2 metabolismus   MeSH
• dítě MeSH
• krysa rodu Rattus MeSH
• lidé MeSH
• membránové transportní proteiny metabolismus   MeSH
• nádorové proteiny metabolismus   MeSH
• nádory prsu * metabolismus   MeSH
• nukleosidy metabolismus   farmakologie   MeSH
• P-glykoprotein metabolismus   MeSH
• P-glykoproteiny metabolismus   MeSH
• placenta * metabolismus   MeSH
• potkani Wistar MeSH
• protein spojený s mnohočetnou rezistencí k lékům 2 MeSH
• proteiny přenášející nukleosidy metabolismus   farmakologie   MeSH
• proteiny spojené s mnohočetnou rezistencí k lékům metabolismus   MeSH
• těhotenství MeSH
• uridin MeSH
• zvířata MeSH
• Check Tag
• dítě MeSH
• krysa rodu Rattus MeSH
• lidé MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 4-nitrobenzylthioinosine MeSH Prohlížeč
• ABC transportér z rodiny G, člen 2 MeSH
• ABCB1 protein, human MeSH Prohlížeč
• ABCC2 protein, human MeSH Prohlížeč
• ABCG2 protein, human MeSH Prohlížeč
• entecavir MeSH Prohlížeč
• membránové transportní proteiny MeSH
• nádorové proteiny MeSH
• nukleosidy MeSH
• P-glykoprotein MeSH
• P-glykoproteiny MeSH
• protein spojený s mnohočetnou rezistencí k lékům 2 MeSH
• proteiny přenášející nukleosidy MeSH
• proteiny spojené s mnohočetnou rezistencí k lékům MeSH
• uridin MeSH

Talazoparib (Talzenna) is a novel poly (adenosine diphosphate-ribose) polymerase (PARP) inhibitor that is clinically used for the therapy of breast cancer. Furthermore, the drug has shown antitumor activity against different cancer types, including non-small cell lung cancer (NSCLC). In this work, we investigated the possible inhibitory interactions of talazoparib toward selected ATP-binding cassette (ABC) drug efflux transporters and cytochrome P450 biotransformation enzymes (CYPs) and evaluated its position in multidrug resistance (MDR). In accumulation studies, talazoparib interacted with the ABCC1 and ABCG2 transporters, but there were no significant effects on ABCB1. Furthermore, incubation assays revealed a negligible capacity of the tested drug to inhibit clinically relevant CYPs. In in vitro drug combination experiments, talazoparib synergistically reversed daunorubicin and mitoxantrone resistance in cells with ABCC1 and ABCG2 expression, respectively. Importantly, the position of an effective MDR modulator was further confirmed in drug combinations performed in ex vivo NSCLC patients-derived explants, whereas the possible victim role was refuted in comparative proliferation experiments. In addition, talazoparib had no significant effects on the mRNA-level expressions of MDR-related ABC transporters in the MCF-7 cellular model. In summary, our study presents a comprehensive overview on the pharmacokinetic drug-drug interactions (DDI) profile of talazoparib. Moreover, we introduced talazoparib as an efficient MDR antagonist.

• Klíčová slova
• ABC transporter, cytochrome P450, multidrug resistance, pharmacokinetic drug–drug interaction, small cell lung cancer, talazoparib,
• MeSH
• ABC transportér z rodiny G, člen 2 genetika   MeSH
• ABC transportéry genetika   metabolismus   MeSH
• lidé MeSH
• mnohočetná léková rezistence MeSH
• nádorové proteiny metabolismus   MeSH
• nádory plic * MeSH
• nemalobuněčný karcinom plic * farmakoterapie   genetika   MeSH
• P-glykoproteiny genetika   MeSH
• systém (enzymů) cytochromů P-450 metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• ABC transportér z rodiny G, člen 2 MeSH
• ABC transportéry MeSH
• ABCB1 protein, human MeSH Prohlížeč
• ABCG2 protein, human MeSH Prohlížeč
• nádorové proteiny MeSH
• P-glykoproteiny MeSH
• systém (enzymů) cytochromů P-450 MeSH
• talazoparib MeSH Prohlížeč

Sonidegib (LDE-225) is a Hedgehog pathway inhibitor used for the therapy of basal cell carcinoma. In addition, the drug is a subject of clinical trials for the treatment of other solid tumors including non-small cell lung cancer (NSCLC). In this study, we explored the potential of sonidegib to act as a perpetrator of drug-drug interactions (DDIs) and modulator of transporter- and enzyme-mediated multidrug resistance (MDR). First, we found that transport functions of ABCB1 and ABCG2 were effectively inhibited by sonidegib in accumulation studies. In contrast, the drug did not cause fluctuations in mRNA levels of tested efflux transporters. In drug combination assays, sonidegib synergistically enhanced the cytotoxicity of daunorubicin and mitoxantrone in ABCB1- and ABCG2-overexpressing cells, respectively. Notably, similar phenomena were also observed in explant tumor cultures derived from NSCLC-suffering patients. In addition, the anticancer effects of sonidegib were not hampered by the expression of the ABC transporters associated with MDR. Last, sonidegib had no significant influence on the activity of CYP3A4 isoform in vitro. In summary, our work suggests that sonidegib can be considered a potential perpetrator of clinical DDIs on ABCB1 and ABCG2. After in vivo evaluation, its chemosensitizing properties might be projected into efficient and safe treatment regimen for the clinical management of NSCLC patients with high ABCB1/ABCG2 expression.

• Klíčová slova
• ABC transporter, Cytochrome P450, Non-small cell lung cancer, Pharmacokinetic resistance, Sonidegib,
• MeSH
• ABC transportér z rodiny G, člen 2 metabolismus   MeSH
• bifenylové sloučeniny MeSH
• chemorezistence MeSH
• cytostatické látky * farmakologie   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• nádorové proteiny metabolismus   MeSH
• nádory plic * farmakoterapie   MeSH
• nemalobuněčný karcinom plic * farmakoterapie   MeSH
• P-glykoproteiny genetika   MeSH
• proteiny hedgehog metabolismus   MeSH
• protinádorové látky * farmakologie   MeSH
• pyridiny MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• ABC transportér z rodiny G, člen 2 MeSH
• ABCB1 protein, human MeSH Prohlížeč
• ABCG2 protein, human MeSH Prohlížeč
• bifenylové sloučeniny MeSH
• cytostatické látky * MeSH
• nádorové proteiny MeSH
• P-glykoproteiny MeSH
• proteiny hedgehog MeSH
• protinádorové látky * MeSH
• pyridiny MeSH
• sonidegib MeSH Prohlížeč

P21-activated kinases (PAKs) regulate processes associated with cytoskeletal rearrangements, such as cell division, adhesion, and migration. The possible regulatory role of PAKs in cell metabolism has not been well explored, but increasing evidence suggests that a cell metabolic phenotype is related to cell interactions with the microenvironment. We analyzed the impact of PAK inhibition by small molecule inhibitors, small interfering RNA, or gene knockout on the rates of mitochondrial respiration and aerobic glycolysis. Pharmacological inhibition of PAK group I by IPA-3 induced a strong decrease in metabolic rates in human adherent cancer cell lines, leukemia/lymphoma cell lines, and primary leukemia cells. The immediate effect of FRAX597, which inhibits PAK kinase activity, was moderate, indicating that PAK nonkinase functions are essential for cell metabolism. Selective downregulation or deletion of PAK2 was associated with a shift toward oxidative phosphorylation. In contrast, PAK1 knockout resulted in increased glycolysis. However, the overall metabolic capacity was not substantially reduced by PAK1 or PAK2 deletion, possibly due to partial redundancy in PAK1/PAK2 regulatory roles or to activation of other compensatory mechanisms.

• Klíčová slova
• cell metabolism, glycolysis, oxidative phosphorylation, p21-activated kinase 1, p21-activated kinase 2,
• MeSH
• HEK293 buňky MeSH
• HeLa buňky MeSH
• lidé MeSH
• mitochondrie enzymologie   genetika   MeSH
• nádorové mikroprostředí * MeSH
• nádorové proteiny genetika   metabolismus   MeSH
• nádory enzymologie   genetika   MeSH
• p21 aktivované kinasy genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• nádorové proteiny MeSH
• p21 aktivované kinasy MeSH
• PAK1 protein, human MeSH Prohlížeč
• PAK2 protein, human MeSH Prohlížeč

The initial activation step in the gating of ubiquitously expressed Orai1 calcium (Ca2+) ion channels represents the activation of the Ca2+-sensor protein STIM1 upon Ca2+ store depletion of the endoplasmic reticulum. Previous studies using constitutively active Orai1 mutants gave rise to, but did not directly test, the hypothesis that STIM1-mediated Orai1 pore opening is accompanied by a global conformational change of all Orai transmembrane domain (TM) helices within the channel complex. We prove that a local conformational change spreads omnidirectionally within the Orai1 complex. Our results demonstrate that these locally induced global, opening-permissive TM motions are indispensable for pore opening and require clearance of a series of Orai1 gating checkpoints. We discovered these gating checkpoints in the middle and cytosolic extended TM domain regions. Our findings are based on a library of double point mutants that contain each one loss-of-function with one gain-of-function point mutation in a series of possible combinations. We demonstrated that an array of loss-of-function mutations are dominant over most gain-of-function mutations within the same as well as of an adjacent Orai subunit. We further identified inter- and intramolecular salt-bridge interactions of Orai subunits as a core element of an opening-permissive Orai channel architecture. Collectively, clearance and synergistic action of all these gating checkpoints are required to allow STIM1 coupling and Orai1 pore opening. Our results unravel novel insights in the preconditions of the unique fingerprint of CRAC channel activation, provide a valuable source for future structural resolutions, and help to understand the molecular basis of disease-causing mutations.

• Klíčová slova
• AND-gate, CRAC channel, Electrophysiology, Gating, Gating checkpoints, Opening-permissive conformation, Orai1, STIM1, Signal propagation,
• MeSH
• bakteriální proteiny genetika   metabolismus   MeSH
• fosfatidylcholiny chemie   metabolismus   MeSH
• gating iontového kanálu genetika   MeSH
• genetické vektory chemie   metabolismus   MeSH
• HEK293 buňky MeSH
• interakční proteinové domény a motivy MeSH
• konformace proteinů, alfa-helix MeSH
• konformace proteinů, beta-řetězec MeSH
• lidé MeSH
• liposomy chemie   metabolismus   MeSH
• luminescentní proteiny genetika   metabolismus   MeSH
• metoda terčíkového zámku MeSH
• mutace MeSH
• nádorové proteiny chemie   genetika   metabolismus   MeSH
• protein ORAI1 chemie   genetika   metabolismus   MeSH
• protein STIM1 chemie   genetika   metabolismus   MeSH
• regulace genové exprese MeSH
• rekombinantní proteiny chemie   genetika   metabolismus   MeSH
• reportérové geny MeSH
• simulace molekulární dynamiky MeSH
• substituce aminokyselin MeSH
• vápník metabolismus   MeSH
• vápníková signalizace * MeSH
• vazba proteinů MeSH
• vazebná místa MeSH
• zelené fluorescenční proteiny genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 1-palmitoyl-2-oleoylphosphatidylcholine MeSH Prohlížeč
• bakteriální proteiny MeSH
• enhanced cyan fluorescent protein MeSH Prohlížeč
• fosfatidylcholiny MeSH
• liposomy MeSH
• luminescentní proteiny MeSH
• nádorové proteiny MeSH
• ORAI1 protein, human MeSH Prohlížeč
• protein ORAI1 MeSH
• protein STIM1 MeSH
• rekombinantní proteiny MeSH
• STIM1 protein, human MeSH Prohlížeč
• vápník MeSH
• yellow fluorescent protein, Bacteria MeSH Prohlížeč
• zelené fluorescenční proteiny MeSH

The knowledge of the structure, function, and abundance of specific proteins related to the EMT process is essential for developing effective diagnostic approaches to cancer with the perspective of diagnosis and therapy of malignancies. The success of all-trans retinoic acid (ATRA) differentiation therapy in acute promyelocytic leukemia has stimulated studies in the treatment of other tumors with ATRA. This review will discuss the impact of ATRA use, emphasizing epithelial-mesenchymal transition (EMT) proteins in breast cancer, of which metastasis and recurrence are major causes of death.

• Klíčová slova
• ATRA, EMT, breast cancer, protein,
• MeSH
• epitelo-mezenchymální tranzice * MeSH
• lidé MeSH
• metastázy nádorů MeSH
• nádorové proteiny agonisté   metabolismus   MeSH
• nádory prsu metabolismus   mortalita   patologie   MeSH
• receptory kyseliny retinové agonisté   metabolismus   MeSH
• tretinoin metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• nádorové proteiny MeSH
• receptory kyseliny retinové MeSH
• tretinoin MeSH