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.

• Keywords
• C10 taxane derivatives, C2 taxane derivatives, C3´ and C3´N taxane derivatives, Resistant breast cancer cells, Resistant ovarian cancer cells,
• MeSH
• Benzoates pharmacology   chemistry   MeSH
• Drug Resistance, Neoplasm * drug effects   MeSH
• Humans MeSH
• MCF-7 Cells MeSH
• Cell Line, Tumor MeSH
• Breast Neoplasms drug therapy   pathology   MeSH
• Ovarian Neoplasms drug therapy   pathology   MeSH
• ATP Binding Cassette Transporter, Subfamily B * metabolism   genetics   MeSH
• Paclitaxel pharmacology   MeSH
• Antineoplastic Agents pharmacology   chemistry   MeSH
• Taxoids pharmacology   chemistry   MeSH
• Structure-Activity Relationship MeSH
• Check Tag
• Humans MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH
• Names of Substances
• ABCB1 protein, human MeSH Browser
• Benzoates MeSH
• ATP Binding Cassette Transporter, Subfamily B * MeSH
• Paclitaxel MeSH
• Antineoplastic Agents MeSH
• Taxoids MeSH

A limited number of studies are devoted to regulating TRIP6 expression in cancer. Hence, we aimed to unveil the regulation of TRIP6 expression in MCF-7 breast cancer cells (with high TRIP6 expression) and taxane-resistant MCF-7 sublines (manifesting even higher TRIP6 expression). We found that TRIP6 transcription is regulated primarily by the cyclic AMP response element (CRE) in hypomethylated proximal promoters in both taxane-sensitive and taxane-resistant MCF-7 cells. Furthermore, in taxane-resistant MCF-7 sublines, TRIP6 co-amplification with the neighboring ABCB1 gene, as witnessed by fluorescence in situ hybridization (FISH), led to TRIP6 overexpression. Ultimately, we found high TRIP6 mRNA levels in progesterone receptor-positive breast cancer and samples resected from premenopausal women.

• Keywords
• ABCB1, CpG methylation, MCF-7, TRIP6, breast cancer, cAMP response element, gene amplification,
• MeSH
• Adaptor Proteins, Signal Transducing genetics   MeSH
• Cyclic AMP MeSH
• Drug Resistance, Neoplasm * genetics   MeSH
• In Situ Hybridization, Fluorescence MeSH
• Humans MeSH
• MCF-7 Cells MeSH
• Neoplasms * genetics   MeSH
• ATP Binding Cassette Transporter, Subfamily B * genetics   MeSH
• LIM Domain Proteins * genetics   MeSH
• Response Elements MeSH
• Taxoids MeSH
• Transcription Factors genetics   MeSH
• Check Tag
• Humans MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH
• Names of Substances
• ABCB1 protein, human MeSH Browser
• Adaptor Proteins, Signal Transducing MeSH
• Cyclic AMP MeSH
• ATP Binding Cassette Transporter, Subfamily B * MeSH
• LIM Domain Proteins * MeSH
• taxane MeSH Browser
• Taxoids MeSH
• Transcription Factors MeSH
• TRIP6 protein, human MeSH Browser

Long-term treatment of cancer with chemotherapeutics leads to the development of resistant forms that reduce treatment options. The main associated mechanism is the overexpression of transport proteins, particularly P-glycoprotein (P-gp, ABCB1). In this study, we have tested the anticancer and multidrug resistance (MDR) modulation activity of 15 selenocompounds. Out of the tested compounds, K3, K4, and K7 achieved the highest sensitization rate in ovarian carcinoma cells (HOC/ADR) that are resistant to the action of the Adriamycin. These compounds induced oxidation stress, inhibited P-gp transport activity and altered ABC gene expression. To verify the effect of compounds, 3D cell models were used to better mimic in vivo conditions. K4 and K7 triggered the most significant ROS release. All selected selenoesters inhibited P-gp efflux in a dose-dependent manner while simultaneously altering the expression of the ABC genes, especially P-gp in paclitaxel-resistant breast carcinoma cells (MCF-7/PAX). K4, and K7 demonstrated sensitization potential in resistant ovarian spheroids. Additionally, all selected selenoesters achieved a high cytotoxic effect in 3D breast and ovarian models, which was comparable to that in 2D cultures. K7 was the only non-competitive P-gp inhibitor, and therefore appears to have considerable potential for the treatment of drug-resistant cancer.

• MeSH
• Drug Resistance, Neoplasm MeSH
• Doxorubicin pharmacology   MeSH
• Ketones pharmacology   MeSH
• Humans MeSH
• Drug Resistance, Multiple MeSH
• Cell Line, Tumor MeSH
• Breast Neoplasms * drug therapy   MeSH
• Antineoplastic Agents * pharmacology   therapeutic use   MeSH
• Check Tag
• Humans MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Doxorubicin MeSH
• Ketones MeSH
• Antineoplastic Agents * MeSH

The main problem precluding successful therapy with conventional taxanes is de novo or acquired resistance to taxanes. Therefore, novel experimental taxane derivatives (Stony Brook taxanes; SB-Ts) are synthesized and tested as potential drugs against resistant solid tumors. Recently, we reported alterations in ABCC3, CPS1, and TRIP6 gene expression in a breast cancer cell line resistant to paclitaxel. The present study aimed to investigate gene expression changes of these three candidate molecules in the highly resistant ovarian carcinoma cells in vitro and corresponding in vivo models treated with paclitaxel and new experimental Stony Brook taxanes of the third generation (SB-T-121605 and SB-T-121606). We also addressed their prognostic meaning in ovarian carcinoma patients treated with taxanes. We estimated and observed changes in mRNA and protein profiles of ABCC3, CPS1, and TRIP6 in resistant and sensitive ovarian cancer cells and after the treatment of resistant ovarian cancer models with paclitaxel and Stony Brook taxanes in vitro and in vivo. Combining Stony Brook taxanes with paclitaxel caused downregulation of CPS1 in the paclitaxel-resistant mouse xenograft tumor model in vivo. Moreover, CPS1 overexpression seems to play a role of a prognostic biomarker of epithelial ovarian carcinoma patients' poor survival. ABCC3 was overexpressed in EOC tumors, but after the treatment with taxanes, its up-regulation disappeared. Based on our results, we can suggest ABCC3 and CPS1 for further investigations as potential therapeutic targets in human cancers.

• Keywords
• ABCC3, CPS1, Stony Brook taxanes, TRIP6, multidrug resistance, ovarian carcinoma, taxanes,
• MeSH
• Adaptor Proteins, Signal Transducing genetics   MeSH
• Drug Resistance, Neoplasm genetics   MeSH
• Down-Regulation drug effects   genetics   MeSH
• Carcinoma, Ovarian Epithelial drug therapy   genetics   MeSH
• Carbamoyl-Phosphate Synthase (Ammonia) genetics   MeSH
• Middle Aged MeSH
• Humans MeSH
• Mice, Nude MeSH
• Mice MeSH
• Biomarkers, Tumor genetics   MeSH
• Cell Line, Tumor MeSH
• Ovarian Neoplasms drug therapy   genetics   MeSH
• Paclitaxel therapeutic use   MeSH
• LIM Domain Proteins genetics   MeSH
• Multidrug Resistance-Associated Proteins genetics   MeSH
• Taxoids therapeutic use   MeSH
• Transcription Factors genetics   MeSH
• Cell Survival drug effects   genetics   MeSH
• Animals MeSH
• Check Tag
• Middle Aged MeSH
• Humans MeSH
• Mice MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Adaptor Proteins, Signal Transducing MeSH
• CPS1 protein, human MeSH Browser
• Carbamoyl-Phosphate Synthase (Ammonia) MeSH
• multidrug resistance-associated protein 3 MeSH Browser
• Biomarkers, Tumor MeSH
• Paclitaxel MeSH
• LIM Domain Proteins MeSH
• Multidrug Resistance-Associated Proteins MeSH
• Taxoids MeSH
• Transcription Factors MeSH
• TRIP6 protein, human MeSH Browser

Fighting resistance to antibiotics and chemotherapeutics has brought bioactive peptides to the fore. Peptaibols are short α-aminoisobutyric acid-containing peptides produced by Trichoderma species. Here, we studied the production of peptaibols by Trichoderma atroviride O1 and evaluated their antibacterial and anticancer activity against drug-sensitive and multidrug-resistant bacterium and cancer cell lines. This was substantiated by an analysis of the activity of the peptaibol synthetase-encoding gene. Atroviridins, 20-residue peptaibols were detected using MALDI-TOF mass spectrometry. Gram-positive bacteria were susceptible to peptaibol-containing extracts of T. atroviride O1. A synergic effect of extract constituents was possible, and the biolo-gical activity of extracts was pronounced in/after the peak of peptaibol synthetase activity. The growth of methicillin-resistant Staphylococcus aureus was reduced to just under 10% compared to the control. The effect of peptaibol-containing extracts was strongly modulated by the lipoteichoic acid and only slightly by the horse blood serum present in the cultivation medium. Peptaibol-containing extracts affected the proliferation of human breast cancer and human ovarian cancer cell lines in a 2D model, including the multidrug-resistant sublines. The peptaibols influenced the size and compactness of the cell lines in a 3D model. Our findings indicate the molecular basis of peptaibol production in T. atroviride O1 and the potential of its peptaibol-containing extracts as antimicrobial/anticancer agents.

• Keywords
• Trichoderma spp., anticancer peptides, antimicrobial peptides, peptaibols,
• MeSH
• Anti-Bacterial Agents pharmacology   MeSH
• Drug Resistance, Bacterial * MeSH
• Fungal Proteins metabolism   MeSH
• Hypocreales enzymology   metabolism   MeSH
• Horses MeSH
• Humans MeSH
• Ligases metabolism   MeSH
• Methicillin-Resistant Staphylococcus aureus drug effects   MeSH
• MCF-7 Cells MeSH
• Cell Line, Tumor MeSH
• Neoplasms drug therapy   MeSH
• Peptaibols analysis   metabolism   pharmacology   MeSH
• Antineoplastic Agents pharmacology   MeSH
• Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Anti-Bacterial Agents MeSH
• Fungal Proteins MeSH
• Ligases MeSH
• Peptaibols MeSH
• Antineoplastic Agents 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.

• Keywords
• 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
• Drug Resistance, Neoplasm * drug effects   MeSH
• Cell Fractionation MeSH
• Carbamoyl-Phosphate Synthase (Ammonia) genetics   metabolism   MeSH
• Humans MeSH
• MCF-7 Cells MeSH
• Mitochondrial Proteins genetics   metabolism   MeSH
• Mitochondria genetics   metabolism   MeSH
• Breast Neoplasms drug therapy   genetics   metabolism   MeSH
• Paclitaxel pharmacology   MeSH
• Proteome MeSH
• Proteomics methods   MeSH
• Gene Expression Regulation, Neoplastic MeSH
• Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization MeSH
• Tandem Mass Spectrometry MeSH
• Gene Silencing MeSH
• Check Tag
• Humans MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• CPS1 protein, human MeSH Browser
• Carbamoyl-Phosphate Synthase (Ammonia) MeSH
• Mitochondrial Proteins MeSH
• Paclitaxel MeSH
• Proteome 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.

• Keywords
• ABCB1 transporter, Acquired resistance to paclitaxel, Breast cancer cells, Molecular docking, Taxane derivates,
• MeSH
• Biological Transport MeSH
• Drug Resistance, Neoplasm * genetics   MeSH
• Antineoplastic Agents, Phytogenic chemistry   metabolism   pharmacology   MeSH
• Humans MeSH
• MCF-7 Cells MeSH
• Molecular Structure MeSH
• Breast Neoplasms drug therapy   genetics   metabolism   pathology   MeSH
• ATP Binding Cassette Transporter, Subfamily B genetics   metabolism   MeSH
• Paclitaxel chemistry   metabolism   pharmacology   MeSH
• Cell Proliferation drug effects   MeSH
• Molecular Docking Simulation MeSH
• Protein Binding MeSH
• Cell Survival drug effects   MeSH
• Dose-Response Relationship, Drug MeSH
• Structure-Activity Relationship MeSH
• Check Tag
• Humans MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH
• Comparative Study MeSH
• Names of Substances
• ABCB1 protein, human MeSH Browser
• Antineoplastic Agents, Phytogenic MeSH
• ATP Binding Cassette Transporter, Subfamily B MeSH
• Paclitaxel MeSH

The development of drug resistance is a major problem which often occurs during anticancer chemotherapies. Photodynamic therapy (PDT) has been studied as an alternative treatment modality for drug-resistant tumors, however the question of resistance to PDT and potential cross-resistance with chemotherapy has yet to be fully answered. To investigate the mechanism of resistance to PDT, we developed an in vitro experimental model system in a mouse mammary carcinoma cell line 4T1. We used two ethylene glycol derivatives of tetraphenylporphyrin, and tetraphenylchlorin derivative, temoporfin, as photosensitizers (PS). PDT-resistant clones were obtained by exposure to a set concentration of PS followed by irradiation with increasing light doses. PDT resistance to soluble glycol porphyrins was mediated mainly by increased drug efflux through ABCB1 (P-glycoprotein) as we demonstrated by specific ABCB1 knockdown experiments, which in turn rescued the sensitivity of resistant cells to PDT. In contrast, resistance raised to temoporfin, which is generally more lipophilic than glycol porphyrins, elicited mechanism based on sequestration of the drug to lysosomes. The resistance that is acquired from a particular PS could be overcome by using a different PS, which is not susceptible to the same mechanism(s) of resistance. Elucidation of the underlying mechanisms in various types of resistance might facilitate improvements in PDT treatment design.

• MeSH
• Drug Resistance, Neoplasm genetics   MeSH
• Ethylene Glycols administration & dosage   chemistry   MeSH
• Photochemotherapy MeSH
• Photosensitizing Agents administration & dosage   chemistry   MeSH
• Gene Knockdown Techniques MeSH
• Glycols chemistry   MeSH
• Humans MeSH
• Mesoporphyrins administration & dosage   chemistry   MeSH
• MCF-7 Cells MeSH
• Mice MeSH
• Mammary Neoplasms, Animal drug therapy   genetics   pathology   MeSH
• ATP Binding Cassette Transporter, Subfamily B, Member 1 genetics   MeSH
• Paclitaxel adverse effects   MeSH
• Porphyrins administration & dosage   chemistry   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Mice MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Ethylene Glycols MeSH
• Photosensitizing Agents MeSH
• Glycols MeSH
• Mesoporphyrins MeSH
• ATP Binding Cassette Transporter, Subfamily B, Member 1 MeSH
• Paclitaxel MeSH
• Porphyrins MeSH
• temoporfin MeSH Browser