We tested the effect of substituents at the (1) C3´, C3´N, (2) C10, and (3) C2-meta-benzoate positions of taxane derivatives on their activity against sensitive versus counterpart paclitaxel-resistant breast (MCF-7) and ovarian (SK-OV-3) cancer cells. We found that (1) non-aromatic groups at both C3´ and C3´N positions, when compared with phenyl groups at the same positions of a taxane derivative, significantly reduced the resistance of ABCB1 expressing MCF-7/PacR and SK-OV-3/PacR cancer cells. This is, at least in the case of the SB-T-1216 series, accompanied by an ineffective decrease of intracellular levels in MCF-7/PacR cells. The low binding affinity of SB-T-1216 in the ABCB1 binding cavity can elucidate these effects. (2) Cyclopropanecarbonyl group at the C10 position, when compared with the H atom, seems to increase the potency and capability of the derivative in overcoming paclitaxel resistance in both models. (3) Derivatives with fluorine and methyl substituents at the C2-meta-benzoate position were variously potent against sensitive and resistant cancer cells. All C2 derivatives were less capable of overcoming acquired resistance to paclitaxel in vitro than non-substituted analogs. Notably, fluorine derivatives SB-T-121205 and 121,206 were more potent against sensitive and resistant SK-OV-3 cells, and derivatives SB-T-121405 and 121,406 were more potent against sensitive and resistant MCF-7 cells. (4) The various structure-activity relationships of SB-T derivatives observed in two cell line models known to express ABCB1 favor their complex interaction not based solely on ABCB1.

• Klíčová slova
• C10 taxane derivatives, C2 taxane derivatives, C3´ and C3´N taxane derivatives, Resistant breast cancer cells, Resistant ovarian cancer cells,
• MeSH
• benzoáty farmakologie   chemie   MeSH
• chemorezistence * účinky léků   MeSH
• lidé MeSH
• MFC-7 buňky MeSH
• nádorové buněčné linie MeSH
• nádory prsu farmakoterapie   patologie   MeSH
• nádory vaječníků farmakoterapie   patologie   MeSH
• P-glykoproteiny * metabolismus   genetika   MeSH
• paclitaxel farmakologie   MeSH
• protinádorové látky farmakologie   chemie   MeSH
• taxoidy farmakologie   chemie   MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• ABCB1 protein, human MeSH Prohlížeč
• benzoáty MeSH
• P-glykoproteiny * MeSH
• paclitaxel MeSH
• protinádorové látky MeSH
• taxoidy MeSH

Identification of novel proteins with changed expression in resistant cancer cells could be helpful in elucidation mechanisms involved in the development of acquired resistance to paclitaxel. In this study, we carried out a 2D-PAGE using the mitochondrial-enriched fraction from paclitaxel-resistant MCF7/PacR cells compared to original paclitaxel-sensitive MCF7 breast cancer cells. Differentially expressed proteins were identified employing mass spectrometry. We found that lysosomal cathepsin D and mitochondrial abhydrolase-domain containing protein 11 (ABHD11) had decreased expression in MCF7/PacR cells. On the other hand, mitochondrial carbamoyl-phosphate synthetase 1 (CPS1) and ATPase family AAA-domain containing protein 3A and 3B (ATAD3A, ATAD3B) were overexpressed in MCF7/PacR cells. Further, we showed that there was no difference in localization of CPS1 in MCF7 and MCF7/PacR cells. We demonstrated a significant increase in the number of CPS1 positive MCF7/PacR cells, using FACS analysis, compared to the number of CPS1 positive MCF7 cells. Silencing of CPS1 expression by specific siRNA had no significant effect on the resistance of MCF7/PacR cells to paclitaxel. To summarize, we identified several novel proteins of a mitochondrial fraction whose role in acquired resistance to paclitaxel in breast cancer cells should be further assessed.

• Klíčová slova
• ATPase family AAA-domain containing protein 3A and 3B (ATAD3A, 3B), abhydrolase-domain containing protein 11 (ABHD11), breast cancer cells, carbamoyl-phosphate synthetase 1 (CPS1), cathepsin D, mitochondria, paclitaxel resistance, two-dimensional electrophoresis,
• MeSH
• chemorezistence * účinky léků   MeSH
• frakcionace buněk MeSH
• karbamoylfosfátsynthasa (amoniak) genetika   metabolismus   MeSH
• lidé MeSH
• MFC-7 buňky MeSH
• mitochondriální proteiny genetika   metabolismus   MeSH
• mitochondrie genetika   metabolismus   MeSH
• nádory prsu farmakoterapie   genetika   metabolismus   MeSH
• paclitaxel farmakologie   MeSH
• proteom MeSH
• proteomika metody   MeSH
• regulace genové exprese u nádorů MeSH
• spektrometrie hmotnostní - ionizace laserem za účasti matrice MeSH
• tandemová hmotnostní spektrometrie MeSH
• umlčování genů MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• CPS1 protein, human MeSH Prohlížeč
• karbamoylfosfátsynthasa (amoniak) MeSH
• mitochondriální proteiny MeSH
• paclitaxel MeSH
• proteom MeSH

We tested the role of substituents at the C3' and C3'N positions of the taxane molecule to identify taxane derivatives capable of overcoming acquired resistance to paclitaxel. Paclitaxel-resistant sublines SK-BR-3/PacR and MCF-7/PacR as well as the original paclitaxel-sensitive breast cancer cell lines SK-BR-3 and MCF-7 were used for testing. Increased expression of the ABCB1 transporter was found to be involved in the acquired resistance. We tested three groups of taxane derivatives: (1) phenyl group at both C3' and C3'N positions, (2) one phenyl at one of the C3' and C3'N positions and a non-aromatic group at the second position, (3) a non-aromatic group at both C3' and C3'N positions. We found that the presence of phenyl groups at both C3' and C3'N positions is associated with low capability of overcoming acquired paclitaxel resistance compared to taxanes containing at least one non-aromatic substituent at the C3' and C3'N positions. The increase in the ATPase activity of ABCB1 transporter after the application of taxanes from the first group was found to be somewhat higher than after the application of taxanes from the third group. Molecular docking studies demonstrated that the docking score was the lowest, i.e. the highest binding affinity, for taxanes from the first group. It was intermediate for taxanes from the second group, and the highest for taxanes from the third group. We conclude that at least one non-aromatic group at the C3' and C3'N positions of the taxane structure, resulting in reduced affinity to the ABCB1 transporter, brings about high capability of taxane to overcome acquired resistance of breast cancer cells to paclitaxel, due to less efficient transport of the taxane compound out of the cancer cells.

• Klíčová slova
• ABCB1 transporter, Acquired resistance to paclitaxel, Breast cancer cells, Molecular docking, Taxane derivates,
• MeSH
• biologický transport MeSH
• chemorezistence * genetika   MeSH
• fytogenní protinádorové látky chemie   metabolismus   farmakologie   MeSH
• lidé MeSH
• MFC-7 buňky MeSH
• molekulární struktura MeSH
• nádory prsu farmakoterapie   genetika   metabolismus   patologie   MeSH
• P-glykoproteiny genetika   metabolismus   MeSH
• paclitaxel chemie   metabolismus   farmakologie   MeSH
• proliferace buněk účinky léků   MeSH
• simulace molekulového dockingu MeSH
• vazba proteinů MeSH
• viabilita buněk účinky léků   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• srovnávací studie MeSH
• Názvy látek
• ABCB1 protein, human MeSH Prohlížeč
• fytogenní protinádorové látky MeSH
• P-glykoproteiny MeSH
• paclitaxel MeSH