Ruthenium complexes with mono-or bis-heterocyclic chelates: DNA/BSA binding, Antioxidant and Anticancer studies
- Maikoo, Sanam, Chakraborty, Abir, Vukea, Nyeleti, Dingle, Laura M K, Samson, William J, de la Mare, Jo-Anne, Edkins, Adrienne L, Booysen, Irvin N
- Authors: Maikoo, Sanam , Chakraborty, Abir , Vukea, Nyeleti , Dingle, Laura M K , Samson, William J , de la Mare, Jo-Anne , Edkins, Adrienne L , Booysen, Irvin N
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165463 , vital:41246 , DOI: 10.1080/07391102.2020.1775126
- Description: Deoxyribonucleic acid (DNA) and bovine serum albumin (BSA) binding interactions for a series of ruthenium heterocyclic complexes were monitored using ultraviolet-visible (UV-Vis) spectrophotometry, fluorescence emission spectroscopy and agarose gel electrophoresis. Investigations of the DNA interactions for the metal complexes revealed that they are groove-binders with intrinsic binding constants in the order of 104 – 107 M−1.
- Full Text:
- Date Issued: 2020
- Authors: Maikoo, Sanam , Chakraborty, Abir , Vukea, Nyeleti , Dingle, Laura M K , Samson, William J , de la Mare, Jo-Anne , Edkins, Adrienne L , Booysen, Irvin N
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165463 , vital:41246 , DOI: 10.1080/07391102.2020.1775126
- Description: Deoxyribonucleic acid (DNA) and bovine serum albumin (BSA) binding interactions for a series of ruthenium heterocyclic complexes were monitored using ultraviolet-visible (UV-Vis) spectrophotometry, fluorescence emission spectroscopy and agarose gel electrophoresis. Investigations of the DNA interactions for the metal complexes revealed that they are groove-binders with intrinsic binding constants in the order of 104 – 107 M−1.
- Full Text:
- Date Issued: 2020
Hsp90α/β associates with the GSK3β/axin1/phospho-β-catenin complex in the human MCF-7 epithelial breast cancer model:
- Cooper, Leanne C, Prinsloo, Earl, Edkins, Adrienne L, Blatch, Gregory L
- Authors: Cooper, Leanne C , Prinsloo, Earl , Edkins, Adrienne L , Blatch, Gregory L
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165096 , vital:41208 , DOI: 10.1016/j.bbrc.2011.08.136
- Description: Hsp90α/β, the signal transduction chaperone, maintains intracellular communication in normal, stem, and cancer cells. The well characterised association of Hsp90α/β with its client kinases form the framework of multiple signalling networks. GSK3β, a known Hsp90α/β client, mediates β-catenin phosphorylation as part of a cytoplasmic destruction complex which targets phospho-β-catenin to the 26S proteasome. The canonical Wnt/β-catenin pathway promotes stem cell self-renewal as well as oncogenesis. The degree of Hsp90α/β involvement in Wnt/β-catenin signalling needs clarification. Here, we describe the association of Hsp90α/β with GSK3β, β-catenin, phospho-β-catenin and the molecular scaffold, axin1, in the human MCF-7 epithelial breast cancer cell model using selective inhibition of Hsp90α/β, confocal laser scanning microscopy and immunoprecipitation. Our findings suggest that Hsp90α/β modulates the phosphorylation of β-catenin by interaction in common complex with GSK3β/axin1/β-catenin.
- Full Text:
- Date Issued: 2011
- Authors: Cooper, Leanne C , Prinsloo, Earl , Edkins, Adrienne L , Blatch, Gregory L
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165096 , vital:41208 , DOI: 10.1016/j.bbrc.2011.08.136
- Description: Hsp90α/β, the signal transduction chaperone, maintains intracellular communication in normal, stem, and cancer cells. The well characterised association of Hsp90α/β with its client kinases form the framework of multiple signalling networks. GSK3β, a known Hsp90α/β client, mediates β-catenin phosphorylation as part of a cytoplasmic destruction complex which targets phospho-β-catenin to the 26S proteasome. The canonical Wnt/β-catenin pathway promotes stem cell self-renewal as well as oncogenesis. The degree of Hsp90α/β involvement in Wnt/β-catenin signalling needs clarification. Here, we describe the association of Hsp90α/β with GSK3β, β-catenin, phospho-β-catenin and the molecular scaffold, axin1, in the human MCF-7 epithelial breast cancer cell model using selective inhibition of Hsp90α/β, confocal laser scanning microscopy and immunoprecipitation. Our findings suggest that Hsp90α/β modulates the phosphorylation of β-catenin by interaction in common complex with GSK3β/axin1/β-catenin.
- Full Text:
- Date Issued: 2011
CHIP: a co-chaperone for degradation by the proteasome
- Authors: Edkins, Adrienne L
- Date: 2015
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/164863 , vital:41179 , ISBN 978-3-319-11730-0 , DOI: 10.1007/978-3-319-11731-7_11
- Description: Protein homeostasis relies on a balance between protein folding and protein degradation. Molecular chaperones like Hsp70 and Hsp90 fulfil well-defined roles in protein folding and conformational stability via ATP dependent reaction cycles. These folding cycles are controlled by associations with a cohort of non-client protein co-chaperones, such as Hop, p23 and Aha1. Pro-folding co-chaperones facilitate the transit of the client protein through the chaperone mediated folding process. However, chaperones are also involved in ubiquitin-mediated proteasomal degradation of client proteins. Similar to folding complexes, the ability of chaperones to mediate protein degradation is regulated by co-chaperones, such as the C terminal Hsp70 binding protein (CHIP).
- Full Text:
- Date Issued: 2015
- Authors: Edkins, Adrienne L
- Date: 2015
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/164863 , vital:41179 , ISBN 978-3-319-11730-0 , DOI: 10.1007/978-3-319-11731-7_11
- Description: Protein homeostasis relies on a balance between protein folding and protein degradation. Molecular chaperones like Hsp70 and Hsp90 fulfil well-defined roles in protein folding and conformational stability via ATP dependent reaction cycles. These folding cycles are controlled by associations with a cohort of non-client protein co-chaperones, such as Hop, p23 and Aha1. Pro-folding co-chaperones facilitate the transit of the client protein through the chaperone mediated folding process. However, chaperones are also involved in ubiquitin-mediated proteasomal degradation of client proteins. Similar to folding complexes, the ability of chaperones to mediate protein degradation is regulated by co-chaperones, such as the C terminal Hsp70 binding protein (CHIP).
- Full Text:
- Date Issued: 2015
STIP1/HOP regulates the actin cytoskeleton through interactions with actin and changes in actin-binding proteins cofilin and profilin:
- Beckley, Samantha Joy, Hunter, Morgan C, Kituyi, Sarah N, Wingate, Ianthe, Chakraborty, Abantika, Schwarz, Kelly, Makhubu, Matodzi P, Rousseau, Robert P, Ruck, Duncan K, de la Mare, Jo-Anne, Blatch, Gregory L, Edkins, Adrienne L
- Authors: Beckley, Samantha Joy , Hunter, Morgan C , Kituyi, Sarah N , Wingate, Ianthe , Chakraborty, Abantika , Schwarz, Kelly , Makhubu, Matodzi P , Rousseau, Robert P , Ruck, Duncan K , de la Mare, Jo-Anne , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165373 , vital:41238 , https://doi.org/10.3390/ijms21093152
- Description: Cell migration plays a vital role in both health and disease. It is driven by reorganization of the actin cytoskeleton, which is regulated by actin-binding proteins cofilin and profilin. Stress-inducible phosphoprotein 1 (STIP1) is a well-described co-chaperone of the Hsp90 chaperone system, and our findings identify a potential regulatory role of STIP1 in actin dynamics. We show that STIP1 can be isolated in complex with actin and Hsp90 from HEK293T cells and directly interacts with actin in vitro via the C-terminal TPR2AB-DP2 domain of STIP1, potentially due to a region spanning two putative actin-binding motifs. We found that STIP1 could stimulate the in vitro ATPase activity of actin, suggesting a potential role in the modulation of F-actin formation. Interestingly, while STIP1 depletion in HEK293T cells had no major effect on total actin levels, it led to increased nuclear accumulation of actin, disorganization of F-actin structures, and an increase and decrease in cofilin and profilin levels, respectively. This study suggests that STIP1 regulates the cytoskeleton by interacting with actin, or via regulating the ratio of proteins known to affect actin dynamics.
- Full Text:
- Date Issued: 2020
- Authors: Beckley, Samantha Joy , Hunter, Morgan C , Kituyi, Sarah N , Wingate, Ianthe , Chakraborty, Abantika , Schwarz, Kelly , Makhubu, Matodzi P , Rousseau, Robert P , Ruck, Duncan K , de la Mare, Jo-Anne , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165373 , vital:41238 , https://doi.org/10.3390/ijms21093152
- Description: Cell migration plays a vital role in both health and disease. It is driven by reorganization of the actin cytoskeleton, which is regulated by actin-binding proteins cofilin and profilin. Stress-inducible phosphoprotein 1 (STIP1) is a well-described co-chaperone of the Hsp90 chaperone system, and our findings identify a potential regulatory role of STIP1 in actin dynamics. We show that STIP1 can be isolated in complex with actin and Hsp90 from HEK293T cells and directly interacts with actin in vitro via the C-terminal TPR2AB-DP2 domain of STIP1, potentially due to a region spanning two putative actin-binding motifs. We found that STIP1 could stimulate the in vitro ATPase activity of actin, suggesting a potential role in the modulation of F-actin formation. Interestingly, while STIP1 depletion in HEK293T cells had no major effect on total actin levels, it led to increased nuclear accumulation of actin, disorganization of F-actin structures, and an increase and decrease in cofilin and profilin levels, respectively. This study suggests that STIP1 regulates the cytoskeleton by interacting with actin, or via regulating the ratio of proteins known to affect actin dynamics.
- Full Text:
- Date Issued: 2020
NMR structural elucidation of channaine, an unusual alkaloid from Sceletium tortuosum:
- Veale, Clinton G L, Chen, Weiyang, Chaudhary, Sushil, Kituyi, Sarah N, Isaacs, Michelle, Hoppe, Heinrich C, Edkins, Adrienne L, Combrinck, Sandra, Mehari, Bewketu, Viljoen, Alvaro
- Authors: Veale, Clinton G L , Chen, Weiyang , Chaudhary, Sushil , Kituyi, Sarah N , Isaacs, Michelle , Hoppe, Heinrich C , Edkins, Adrienne L , Combrinck, Sandra , Mehari, Bewketu , Viljoen, Alvaro
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164345 , vital:41110 , DOI: 10.1016/j.phytol.2017.11.018
- Description: Chemical interrogation of the Sceletium genus and Amaryllidaceae family of plants has yielded a diverse array of aryl-hydroindole containing alkaloids. Included in this class is channaine, which was tentatively identified, without comprehensive structural elucidation from Sceletium tortuosum in 1957. Following its isolation from S. strictum, the structure of channaine was eventually resolved by X-ray crystallographic analysis, which revealed an unusual cage-like ring structure at the interface of two aryl-hydroindole subunits. However, since this report in 1978, channaine has not re-appeared in the literature. In this letter, the full NMR characterisation of channaine, isolated from S. tortuosum collected from St Helena in the Western Cape Province of South Africa, is reported for the first time.
- Full Text:
- Date Issued: 2018
- Authors: Veale, Clinton G L , Chen, Weiyang , Chaudhary, Sushil , Kituyi, Sarah N , Isaacs, Michelle , Hoppe, Heinrich C , Edkins, Adrienne L , Combrinck, Sandra , Mehari, Bewketu , Viljoen, Alvaro
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164345 , vital:41110 , DOI: 10.1016/j.phytol.2017.11.018
- Description: Chemical interrogation of the Sceletium genus and Amaryllidaceae family of plants has yielded a diverse array of aryl-hydroindole containing alkaloids. Included in this class is channaine, which was tentatively identified, without comprehensive structural elucidation from Sceletium tortuosum in 1957. Following its isolation from S. strictum, the structure of channaine was eventually resolved by X-ray crystallographic analysis, which revealed an unusual cage-like ring structure at the interface of two aryl-hydroindole subunits. However, since this report in 1978, channaine has not re-appeared in the literature. In this letter, the full NMR characterisation of channaine, isolated from S. tortuosum collected from St Helena in the Western Cape Province of South Africa, is reported for the first time.
- Full Text:
- Date Issued: 2018
Knockdown of Hop downregulates RhoC expression, and decreases pseudopodia formation and migration in cancer cell lines:
- Willmer, Tarryn, Contu, Lara, Blatch, Gregory L, Edkins, Adrienne L
- Authors: Willmer, Tarryn , Contu, Lara , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165196 , vital:41217 , DOI: 10.1016/j.canlet.2012.09.021
- Description: The Hsp90/Hsp70 organising protein (Hop) is a co-chaperone that mediates the interaction of Hsp90 and Hsp70 molecular chaperones during assembly of Hsp90 complexes in cells. Formation of Hsp90 complexes is a key intermediate step in the maturation and homeostasis of oncoproteins and several hormone receptors. In this paper, we demonstrate that knockdown of Hop decreased migration of Hs578T and MDA-MB-231 breast cancer cells. Hop was identified in isolated pseudopodia fractions; it colocalised with actin in lamellipodia, and co-sedimented with purified actin in vitro. Knockdown of Hop caused a decrease in the level of RhoC GTPase, and significantly inhibited pseudopodia formation in Hs578T cells. Our data suggest that Hop regulates directional cell migration by multiple unknown mechanisms.
- Full Text:
- Date Issued: 2013
- Authors: Willmer, Tarryn , Contu, Lara , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165196 , vital:41217 , DOI: 10.1016/j.canlet.2012.09.021
- Description: The Hsp90/Hsp70 organising protein (Hop) is a co-chaperone that mediates the interaction of Hsp90 and Hsp70 molecular chaperones during assembly of Hsp90 complexes in cells. Formation of Hsp90 complexes is a key intermediate step in the maturation and homeostasis of oncoproteins and several hormone receptors. In this paper, we demonstrate that knockdown of Hop decreased migration of Hs578T and MDA-MB-231 breast cancer cells. Hop was identified in isolated pseudopodia fractions; it colocalised with actin in lamellipodia, and co-sedimented with purified actin in vitro. Knockdown of Hop caused a decrease in the level of RhoC GTPase, and significantly inhibited pseudopodia formation in Hs578T cells. Our data suggest that Hop regulates directional cell migration by multiple unknown mechanisms.
- Full Text:
- Date Issued: 2013
Halogenated oxindole and indoles from the South African marine ascidian Distaplia skoogi:
- Bromley, Candice L, Parker-Nance, Shirley, de la Mare, Jo-Anne, Edkins, Adrienne L, Beukes, Denzil R, Davies-Coleman, Michael T
- Authors: Bromley, Candice L , Parker-Nance, Shirley , de la Mare, Jo-Anne , Edkins, Adrienne L , Beukes, Denzil R , Davies-Coleman, Michael T
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164918 , vital:41184
- Description: The known 3,6-dibromoindole (1), 6-bromo-3-chloroindole (2) and 6-bromo-2-oxindole (3) were isolated from the marine ascidian (sea squirt) Distapia skoogi collected from Algoa Bay, South Africa. Standard spectroscopic techniques were used to elucidate the structures of 1-3. All three compounds were found to be moderately cytotoxic to metastatic MDA-MB-231 breast cancer cells.
- Full Text:
- Date Issued: 2013
- Authors: Bromley, Candice L , Parker-Nance, Shirley , de la Mare, Jo-Anne , Edkins, Adrienne L , Beukes, Denzil R , Davies-Coleman, Michael T
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164918 , vital:41184
- Description: The known 3,6-dibromoindole (1), 6-bromo-3-chloroindole (2) and 6-bromo-2-oxindole (3) were isolated from the marine ascidian (sea squirt) Distapia skoogi collected from Algoa Bay, South Africa. Standard spectroscopic techniques were used to elucidate the structures of 1-3. All three compounds were found to be moderately cytotoxic to metastatic MDA-MB-231 breast cancer cells.
- Full Text:
- Date Issued: 2013
The networking of chaperones by co-chaperones: control of cellular protein homeostasis
- Edkins, Adrienne L, Blatch, Gregory L
- Authors: Edkins, Adrienne L , Blatch, Gregory L
- Date: 2014
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/165107 , vital:41209 , ISBN 978-3-319-11731-7
- Description: Co-chaperones are important mediators of the outcome of chaperone assisted protein homeostasis, which is a dynamic balance between the integrated processes of protein folding, degradation and translocation. The Networking of Chaperones by Co-chaperones describes how the function of the major molecular chaperones is regulated by a cohort of diverse non-client proteins, known as co-chaperones. The second edition includes the current status of the field and descriptions of a number of novel co-chaperones that have been recently identified. This new edition has a strong focus on the role of co-chaperones in human disease and as putative drug targets. The book will be a resource for both newcomers and established researchers in the field of cell stress and chaperones, as well as those interested in cross-cutting disciplines such as cellular networks and systems biology.
- Full Text:
- Date Issued: 2014
- Authors: Edkins, Adrienne L , Blatch, Gregory L
- Date: 2014
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/165107 , vital:41209 , ISBN 978-3-319-11731-7
- Description: Co-chaperones are important mediators of the outcome of chaperone assisted protein homeostasis, which is a dynamic balance between the integrated processes of protein folding, degradation and translocation. The Networking of Chaperones by Co-chaperones describes how the function of the major molecular chaperones is regulated by a cohort of diverse non-client proteins, known as co-chaperones. The second edition includes the current status of the field and descriptions of a number of novel co-chaperones that have been recently identified. This new edition has a strong focus on the role of co-chaperones in human disease and as putative drug targets. The book will be a resource for both newcomers and established researchers in the field of cell stress and chaperones, as well as those interested in cross-cutting disciplines such as cellular networks and systems biology.
- Full Text:
- Date Issued: 2014
Hop/STIP1 depletion alters nuclear structure via depletion of nuclear structural protein emerin:
- Kituyi, Sarah N, Edkins, Adrienne L
- Authors: Kituyi, Sarah N , Edkins, Adrienne L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164435 , vital:41118 , https://doi.org/10.1016/j.bbrc.2018.11.073
- Description: Hop/STIP1 is a co-chaperone of Hsp70 and Hsp90 that regulates a number of cell biology processes via interactions with cellular proteins. Here we report a new relationship between Hop and the nuclear structural protein emerin in maintenance of nuclear morphology. Depletion or overexpression of Hop resulted in the reduction of emerin protein levels via proteasomal and lysosomal pathways.
- Full Text:
- Date Issued: 2018
- Authors: Kituyi, Sarah N , Edkins, Adrienne L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164435 , vital:41118 , https://doi.org/10.1016/j.bbrc.2018.11.073
- Description: Hop/STIP1 is a co-chaperone of Hsp70 and Hsp90 that regulates a number of cell biology processes via interactions with cellular proteins. Here we report a new relationship between Hop and the nuclear structural protein emerin in maintenance of nuclear morphology. Depletion or overexpression of Hop resulted in the reduction of emerin protein levels via proteasomal and lysosomal pathways.
- Full Text:
- Date Issued: 2018
Sarqaquinoic acid and related synthetic naphthoquinones inhibit the function of Hsp90
- Chiwakata, M, de la Mare, Jo-Anne, Edkins, Adrienne L, Beukes, Denzil R
- Authors: Chiwakata, M , de la Mare, Jo-Anne , Edkins, Adrienne L , Beukes, Denzil R
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66324 , vital:28933 , https://doi.org/10.1055/s-0036-1596751
- Description: publisher version , Heat shock protein 90 (Hsp90) is of critical importance in the proper folding of numerous proteins, including those involved in cancer. Consequently, there is significant interest in the discovery and development of Hsp90 inhibitors as anticancer drugs. In this study, we investigated the ability of sargaquinoic acid (SQA) and selected naphthoquinone derivatives to inhibit Hsp90 function. SQA was isolated and purified from Sargassum incisifolium while the naphthoquinones were synthesised via a straightforward sequence incorporating a Diels-Alder reaction between benzoquinone derivatives and myrcene followed by coupling with substituted alkyl or arylamines. Hsp90 inhibition was assessed by a client protein degradation assay. At a concentration of 1µM, SQA showed almost complete inhibition of Hsp90 but only moderate antiproliferative effects (IC50 658µM) against a Hs578T breast cancer carcinoma cell line. Interestingly, the most potent synthetic aminonaphthoquinone inhibited Hsp90 function by 50% at a concentration of 1µM but showed much improved activity against the Hs578T cell line (IC50 0.32µM). Furthermore, unlike geldanamycin, none of the compounds tested upregulates Hsp70 suggesting that these compounds may bind to the C-terminal end of Hsp90.
- Full Text: false
- Date Issued: 2016
- Authors: Chiwakata, M , de la Mare, Jo-Anne , Edkins, Adrienne L , Beukes, Denzil R
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66324 , vital:28933 , https://doi.org/10.1055/s-0036-1596751
- Description: publisher version , Heat shock protein 90 (Hsp90) is of critical importance in the proper folding of numerous proteins, including those involved in cancer. Consequently, there is significant interest in the discovery and development of Hsp90 inhibitors as anticancer drugs. In this study, we investigated the ability of sargaquinoic acid (SQA) and selected naphthoquinone derivatives to inhibit Hsp90 function. SQA was isolated and purified from Sargassum incisifolium while the naphthoquinones were synthesised via a straightforward sequence incorporating a Diels-Alder reaction between benzoquinone derivatives and myrcene followed by coupling with substituted alkyl or arylamines. Hsp90 inhibition was assessed by a client protein degradation assay. At a concentration of 1µM, SQA showed almost complete inhibition of Hsp90 but only moderate antiproliferative effects (IC50 658µM) against a Hs578T breast cancer carcinoma cell line. Interestingly, the most potent synthetic aminonaphthoquinone inhibited Hsp90 function by 50% at a concentration of 1µM but showed much improved activity against the Hs578T cell line (IC50 0.32µM). Furthermore, unlike geldanamycin, none of the compounds tested upregulates Hsp70 suggesting that these compounds may bind to the C-terminal end of Hsp90.
- Full Text: false
- Date Issued: 2016
In vitro analysis of putative cancer stem cell populations and chemosensitivity in the SW480 and SW620 colon cancer metastasis model:
- Slater, Cindy, de la Mare, Jo-Anne, Edkins, Adrienne L
- Authors: Slater, Cindy , de la Mare, Jo-Anne , Edkins, Adrienne L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164401 , vital:41115 , DOI: 10.3892/ol.2018.8431
- Description: The cancer stem cell (CSC) theory implicates a small subpopulation of cells with stem like properties, which is responsible for tumour initiation, development and metastasis. The unique biological and functional characteristics of CSCs, widely associated with treatment resistance, indicate an association between metastasis and stemness. It was hypothesised that metastatic cell lines may be enriched in CSCs and that this would correlate with a more resistant tumour. In the present study, the SW480 and SW620 paired cell lines derived from a colon adenocarcinoma and its lymph node metastasis, respectively were compared as an in vitro model of cancer progression. Their chemosensitivity and CSC properties were investigated. A range of in vitro assays were performed, including the side population assay, ALDEFLUOR assay, tumoursphere assay and assessment of CSC associated surface phenotypes.
- Full Text:
- Date Issued: 2018
- Authors: Slater, Cindy , de la Mare, Jo-Anne , Edkins, Adrienne L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164401 , vital:41115 , DOI: 10.3892/ol.2018.8431
- Description: The cancer stem cell (CSC) theory implicates a small subpopulation of cells with stem like properties, which is responsible for tumour initiation, development and metastasis. The unique biological and functional characteristics of CSCs, widely associated with treatment resistance, indicate an association between metastasis and stemness. It was hypothesised that metastatic cell lines may be enriched in CSCs and that this would correlate with a more resistant tumour. In the present study, the SW480 and SW620 paired cell lines derived from a colon adenocarcinoma and its lymph node metastasis, respectively were compared as an in vitro model of cancer progression. Their chemosensitivity and CSC properties were investigated. A range of in vitro assays were performed, including the side population assay, ALDEFLUOR assay, tumoursphere assay and assessment of CSC associated surface phenotypes.
- Full Text:
- Date Issued: 2018
Cytotoxicity of lapachol, β-lapachone and related synthetic 1, 4-naphthoquinones against oesophageal cancer cells:
- Sunassee, Suthananda N, Veale, Clinton G L, Shunmoogam-Gounden, Nelusha, Osoniyi, Omalaja, Hendricks, Denver T, Caira, Mino R, de la Mare, Jo-Anne, Edkins, Adrienne L, Pinto, Antônio V, da Silva Junior, Eufrânio N, Davies-Coleman, Michael T
- Authors: Sunassee, Suthananda N , Veale, Clinton G L , Shunmoogam-Gounden, Nelusha , Osoniyi, Omalaja , Hendricks, Denver T , Caira, Mino R , de la Mare, Jo-Anne , Edkins, Adrienne L , Pinto, Antônio V , da Silva Junior, Eufrânio N , Davies-Coleman, Michael T
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165207 , vital:41218 , DOI: 10.1016/j.ejmech.2012.12.048
- Description: Naphthoquinones have been found to have a wide range of biological activities, including cytotoxicity to cancer cells. The secondary metabolites lapachol, α- and β-lapachone and a series of 25 related synthetic 1,4-naphthoquinones were screened against the oesophageal cancer cell line (WHCO1). Most of the compounds exhibited enhanced cytotoxicity (IC50 1.6–11.7 μM) compared to the current drug of choice cisplatin (IC50 = 16.5 μM).
- Full Text:
- Date Issued: 2013
- Authors: Sunassee, Suthananda N , Veale, Clinton G L , Shunmoogam-Gounden, Nelusha , Osoniyi, Omalaja , Hendricks, Denver T , Caira, Mino R , de la Mare, Jo-Anne , Edkins, Adrienne L , Pinto, Antônio V , da Silva Junior, Eufrânio N , Davies-Coleman, Michael T
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165207 , vital:41218 , DOI: 10.1016/j.ejmech.2012.12.048
- Description: Naphthoquinones have been found to have a wide range of biological activities, including cytotoxicity to cancer cells. The secondary metabolites lapachol, α- and β-lapachone and a series of 25 related synthetic 1,4-naphthoquinones were screened against the oesophageal cancer cell line (WHCO1). Most of the compounds exhibited enhanced cytotoxicity (IC50 1.6–11.7 μM) compared to the current drug of choice cisplatin (IC50 = 16.5 μM).
- Full Text:
- Date Issued: 2013
Human DNAJ in cancer and stem cells:
- Sterrenberg, Jason N, Edkins, Adrienne L, Blatch, Gregory L
- Authors: Sterrenberg, Jason N , Edkins, Adrienne L , Blatch, Gregory L
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165118 , vital:41210 , DOI: 10.1016/j.canlet.2011.08.019
- Description: The heat shock protein 40 kDa (HSP40/DNAJ) co-chaperones constitute the largest and most diverse sub-group of the heat shock protein (HSP) family. DNAJ are widely accepted as regulators of HSP70 function, but also have roles as co-chaperones for the HSP90 chaperone machine, and a growing number of biological functions that may be independent of either of these chaperones. The DNAJ proteins are differentially expressed in human tissues and demonstrate the capacity to function to both promote and suppress cancer development by acting as chaperones for tumour suppressors or oncoproteins. We review the current literature on the function and expression of DNAJ in cancer, stem cells and cancer stem cells. Combining data from gene expression, proteomics and studies in other systems, we propose that DNAJ will be key regulators of cancer, stem cell and possibly cancer stem cell function. The diversity of DNAJ and their assorted roles in a range of biological functions means that selected DNAJ, provided there is limited redundancy and that a specific link to malignancy can be established, may yet provide an attractive target for specific and selective drug design for the development of anti-cancer treatments.
- Full Text:
- Date Issued: 2011
- Authors: Sterrenberg, Jason N , Edkins, Adrienne L , Blatch, Gregory L
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165118 , vital:41210 , DOI: 10.1016/j.canlet.2011.08.019
- Description: The heat shock protein 40 kDa (HSP40/DNAJ) co-chaperones constitute the largest and most diverse sub-group of the heat shock protein (HSP) family. DNAJ are widely accepted as regulators of HSP70 function, but also have roles as co-chaperones for the HSP90 chaperone machine, and a growing number of biological functions that may be independent of either of these chaperones. The DNAJ proteins are differentially expressed in human tissues and demonstrate the capacity to function to both promote and suppress cancer development by acting as chaperones for tumour suppressors or oncoproteins. We review the current literature on the function and expression of DNAJ in cancer, stem cells and cancer stem cells. Combining data from gene expression, proteomics and studies in other systems, we propose that DNAJ will be key regulators of cancer, stem cell and possibly cancer stem cell function. The diversity of DNAJ and their assorted roles in a range of biological functions means that selected DNAJ, provided there is limited redundancy and that a specific link to malignancy can be established, may yet provide an attractive target for specific and selective drug design for the development of anti-cancer treatments.
- Full Text:
- Date Issued: 2011
Detection of the in vitro modulation of Plasmodium falciparum Arf1 by Sec7 and ArfGAP domains using a colorimetric plate-based assay:
- Swart, Tarryn, Khan, Farrah D, Ntlantsana, Apelele, Laming, Dustin, Veale, Clinton G L, Przyborski, Jude M, Edkins, Adrienne L, Hoppe, Heinrich C
- Authors: Swart, Tarryn , Khan, Farrah D , Ntlantsana, Apelele , Laming, Dustin , Veale, Clinton G L , Przyborski, Jude M , Edkins, Adrienne L , Hoppe, Heinrich C
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165418 , vital:41242 , https://0-doi.org.wam.seals.ac.za/10.1038/s41598-020-61101-3
- Description: The regulation of human Arf1 GTPase activity by ArfGEFs that stimulate GDP/GTP exchange and ArfGAPs that mediate GTP hydrolysis has attracted attention for the discovery of Arf1 inhibitors as potential anti-cancer agents. The malaria parasite Plasmodium falciparum encodes a Sec7 domain-containing protein - presumably an ArfGEF - and two putative ArfGAPs, as well as an Arf1 homologue (PfArf1) that is essential for blood-stage parasite viability. However, ArfGEF and ArfGAP-mediated activation/deactivation of PfArf1 has not been demonstrated.
- Full Text:
- Date Issued: 2020
- Authors: Swart, Tarryn , Khan, Farrah D , Ntlantsana, Apelele , Laming, Dustin , Veale, Clinton G L , Przyborski, Jude M , Edkins, Adrienne L , Hoppe, Heinrich C
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165418 , vital:41242 , https://0-doi.org.wam.seals.ac.za/10.1038/s41598-020-61101-3
- Description: The regulation of human Arf1 GTPase activity by ArfGEFs that stimulate GDP/GTP exchange and ArfGAPs that mediate GTP hydrolysis has attracted attention for the discovery of Arf1 inhibitors as potential anti-cancer agents. The malaria parasite Plasmodium falciparum encodes a Sec7 domain-containing protein - presumably an ArfGEF - and two putative ArfGAPs, as well as an Arf1 homologue (PfArf1) that is essential for blood-stage parasite viability. However, ArfGEF and ArfGAP-mediated activation/deactivation of PfArf1 has not been demonstrated.
- Full Text:
- Date Issued: 2020
Hop depletion reduces HSF1 levels and activity and coincides with reduced stress resilience:
- Chakraborty, Abantika, Edkins, Adrienne L
- Authors: Chakraborty, Abantika , Edkins, Adrienne L
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165440 , vital:41244 , https://doi.org/10.1016/j.bbrc.2020.04.072
- Description: Heat-shock factor 1 (HSF1) regulates the transcriptional response to stress and controls expression of molecular chaperones required for cell survival. Here we report that HSF1 is regulated by the abundance of the Hsp70-Hsp90 organizing protein (Hop/STIP1).
- Full Text:
- Date Issued: 2020
- Authors: Chakraborty, Abantika , Edkins, Adrienne L
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165440 , vital:41244 , https://doi.org/10.1016/j.bbrc.2020.04.072
- Description: Heat-shock factor 1 (HSF1) regulates the transcriptional response to stress and controls expression of molecular chaperones required for cell survival. Here we report that HSF1 is regulated by the abundance of the Hsp70-Hsp90 organizing protein (Hop/STIP1).
- Full Text:
- Date Issued: 2020
General structural and functional features of molecular chaperones:
- Edkins, Adrienne L, Boshoff, Aileen
- Authors: Edkins, Adrienne L , Boshoff, Aileen
- Date: 2014
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/164808 , vital:41174 , ISBN 978-94-007-7437-7 , DOI: 10.1007/978-94-007-7438-4_2
- Description: Molecular chaperones are a group of structurally diverse and highly conserved ubiquitous proteins. They play crucial roles in facilitating the correct folding of proteins in vivo by preventing protein aggregation or facilitating the appropriate folding and assembly of proteins. Heat shock proteins form the major class of molecular chaperones that are responsible for protein folding events in the cell. This is achieved by ATP-dependent (folding machines) or ATP-independent mechanisms (holders). Heat shock proteins are induced by a variety of stresses, besides heat shock. The large and varied heat shock protein class is categorised into several subfamilies based on their sizes in kDa namely, small Hsps (HSPB), Hsp40 (DNAJ), Hsp60 (HSPD/E; Chaperonins), Hsp70 (HSPA), Hsp90 (HSPC), and Hsp100.
- Full Text:
- Date Issued: 2014
- Authors: Edkins, Adrienne L , Boshoff, Aileen
- Date: 2014
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/164808 , vital:41174 , ISBN 978-94-007-7437-7 , DOI: 10.1007/978-94-007-7438-4_2
- Description: Molecular chaperones are a group of structurally diverse and highly conserved ubiquitous proteins. They play crucial roles in facilitating the correct folding of proteins in vivo by preventing protein aggregation or facilitating the appropriate folding and assembly of proteins. Heat shock proteins form the major class of molecular chaperones that are responsible for protein folding events in the cell. This is achieved by ATP-dependent (folding machines) or ATP-independent mechanisms (holders). Heat shock proteins are induced by a variety of stresses, besides heat shock. The large and varied heat shock protein class is categorised into several subfamilies based on their sizes in kDa namely, small Hsps (HSPB), Hsp40 (DNAJ), Hsp60 (HSPD/E; Chaperonins), Hsp70 (HSPA), Hsp90 (HSPC), and Hsp100.
- Full Text:
- Date Issued: 2014
Sequence and domain conservation of the coelacanth Hsp40 and Hsp90 chaperones suggests conservation of function
- Tastan Bishop, Özlem, Edkins, Adrienne L, Blatch, Gregory L
- Authors: Tastan Bishop, Özlem , Edkins, Adrienne L , Blatch, Gregory L
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126932 , vital:35936 , https://doi.10.1002/jez.b.22541
- Description: Molecular chaperones and their associated co‐chaperones play an important role in preserving and regulating the active conformational state of cellular proteins. The chaperone complement of the Indonesian Coelacanth, Latimeria menadoensis, was elucidated using transcriptomic sequences. Heat shock protein 90 (Hsp90) and heat shock protein 40 (Hsp40) chaperones, and associated cochaperones were focused on, and homologous human sequences were used to search the sequence databases. Coelacanth homologs of the cytosolic, mitochondrial and endoplasmic reticulum (ER) homologs of human Hsp90 were identified, as well as all of the major co‐chaperones of the cytosolic isoform. Most of the human Hsp40s were found to have coelacanth homologs, and the data suggested that all of the chaperone machinery for protein folding at the ribosome, protein translocation to cellular compartments such as the ER and protein degradation were conserved. Some interesting similarities and differences were identified when interrogating human, mouse, and zebrafish homologs. For example, DnaJB13 is predicted to be a non‐functional Hsp40 in humans, mouse, and zebrafish due to a corrupted histidine‐proline‐aspartic acid (HPD) motif, while the coelacanth homolog has an intact HPD. These and other comparisons enabled important functional and evolutionary questions to be posed for future experimental studies.
- Full Text:
- Date Issued: 2014
- Authors: Tastan Bishop, Özlem , Edkins, Adrienne L , Blatch, Gregory L
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126932 , vital:35936 , https://doi.10.1002/jez.b.22541
- Description: Molecular chaperones and their associated co‐chaperones play an important role in preserving and regulating the active conformational state of cellular proteins. The chaperone complement of the Indonesian Coelacanth, Latimeria menadoensis, was elucidated using transcriptomic sequences. Heat shock protein 90 (Hsp90) and heat shock protein 40 (Hsp40) chaperones, and associated cochaperones were focused on, and homologous human sequences were used to search the sequence databases. Coelacanth homologs of the cytosolic, mitochondrial and endoplasmic reticulum (ER) homologs of human Hsp90 were identified, as well as all of the major co‐chaperones of the cytosolic isoform. Most of the human Hsp40s were found to have coelacanth homologs, and the data suggested that all of the chaperone machinery for protein folding at the ribosome, protein translocation to cellular compartments such as the ER and protein degradation were conserved. Some interesting similarities and differences were identified when interrogating human, mouse, and zebrafish homologs. For example, DnaJB13 is predicted to be a non‐functional Hsp40 in humans, mouse, and zebrafish due to a corrupted histidine‐proline‐aspartic acid (HPD) motif, while the coelacanth homolog has an intact HPD. These and other comparisons enabled important functional and evolutionary questions to be posed for future experimental studies.
- Full Text:
- Date Issued: 2014
Use of a non-hepatic cell line highlights limitations associated with cell-based assessment of metabolically induced toxicity:
- Weyers, Carli, Dingle, Laura M K, Wilhelmi, Brendan S, Edkins, Adrienne L, Veale, Clinton G
- Authors: Weyers, Carli , Dingle, Laura M K , Wilhelmi, Brendan S , Edkins, Adrienne L , Veale, Clinton G
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/160290 , vital:40431 , DOI: 10.1080/01480545.2019.1585869
- Description: Metabolically induced drug-toxicity is a major cause of drug failure late in drug optimization phases. Accordingly, in vitro metabolic profiling of compounds is being introduced at earlier stages of the drug discovery pipeline. An increasingly common method to obtain these profiles is through overexpression of key CYP450 metabolic enzymes in immortalized liver cells, to generate competent hepatocyte surrogates. Enhanced cytotoxicity is presumed to be due to toxic metabolite production via the overexpressed enzyme. However, metabolically induced toxicity is a complex multi-parameter phenomenon and the potential background contribution to metabolism arising from the use of liver cells which endogenously express CYP450 isoforms is consistently overlooked. In this study, we sought to reduce the potential background interference by applying this methodology in kidney-derived HEK293 cells which lack endogenous CYP450 expression.
- Full Text:
- Date Issued: 2020
- Authors: Weyers, Carli , Dingle, Laura M K , Wilhelmi, Brendan S , Edkins, Adrienne L , Veale, Clinton G
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/160290 , vital:40431 , DOI: 10.1080/01480545.2019.1585869
- Description: Metabolically induced drug-toxicity is a major cause of drug failure late in drug optimization phases. Accordingly, in vitro metabolic profiling of compounds is being introduced at earlier stages of the drug discovery pipeline. An increasingly common method to obtain these profiles is through overexpression of key CYP450 metabolic enzymes in immortalized liver cells, to generate competent hepatocyte surrogates. Enhanced cytotoxicity is presumed to be due to toxic metabolite production via the overexpressed enzyme. However, metabolically induced toxicity is a complex multi-parameter phenomenon and the potential background contribution to metabolism arising from the use of liver cells which endogenously express CYP450 isoforms is consistently overlooked. In this study, we sought to reduce the potential background interference by applying this methodology in kidney-derived HEK293 cells which lack endogenous CYP450 expression.
- Full Text:
- Date Issued: 2020
Repurposing a polymer precursor: Synthesis and in vitro medicinal potential of ferrocenyl 1, 3-benzoxazine derivatives
- Mbaba, Mziyanda, Dingle, Laura M K, Cash, Devon, de la Mare, Jo-Anne, Laming, Dustin, Taylor, Dale, Hoppe, Heinrich C, Edkins, Adrienne L, Khanye, Setshaba D
- Authors: Mbaba, Mziyanda , Dingle, Laura M K , Cash, Devon , de la Mare, Jo-Anne , Laming, Dustin , Taylor, Dale , Hoppe, Heinrich C , Edkins, Adrienne L , Khanye, Setshaba D
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165395 , vital:41240 , https://doi.org/10.1016/j.ejmech.2019.111924
- Description: Cancer and malaria remain relevant pathologies in modern medicinal chemistry endeavours. This is compounded by the threat of development of resistance to existing clinical drugs in use as first-line option for treatment of these diseases. To counter this threat, strategies such as drug repurposing and hybridization are constantly adapted in contemporary drug discovery for the expansion of the drug arsenal and generation of novel chemotypes with potential to avert or delay resistance. In the present study, a polymer precursor scaffold, 1,3-benzoxazine, has been repurposed by incorporation of an organometallic ferrocene unit to produce a novel class of compounds showing in vitro biological activity against breast cancer, malaria and trypanosomiasis.
- Full Text:
- Date Issued: 2020
- Authors: Mbaba, Mziyanda , Dingle, Laura M K , Cash, Devon , de la Mare, Jo-Anne , Laming, Dustin , Taylor, Dale , Hoppe, Heinrich C , Edkins, Adrienne L , Khanye, Setshaba D
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165395 , vital:41240 , https://doi.org/10.1016/j.ejmech.2019.111924
- Description: Cancer and malaria remain relevant pathologies in modern medicinal chemistry endeavours. This is compounded by the threat of development of resistance to existing clinical drugs in use as first-line option for treatment of these diseases. To counter this threat, strategies such as drug repurposing and hybridization are constantly adapted in contemporary drug discovery for the expansion of the drug arsenal and generation of novel chemotypes with potential to avert or delay resistance. In the present study, a polymer precursor scaffold, 1,3-benzoxazine, has been repurposed by incorporation of an organometallic ferrocene unit to produce a novel class of compounds showing in vitro biological activity against breast cancer, malaria and trypanosomiasis.
- Full Text:
- Date Issued: 2020
Cancer stem cells in breast cancer and metastasis:
- Lawson, Jessica C, Blatch, Gregory L, Edkins, Adrienne L
- Authors: Lawson, Jessica C , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165057 , vital:41205 , DOI: 10.1007/s10549-009-0524-9
- Description: The cancer stem cell theory poses that cancers develop from a subset of malignant cells that possess stem cell characteristics and has been proposed to account for the development of a variety of malignancies, including breast cancer. These cancer stem cells (CSC) possess characteristics of both stem cells and cancer cells, in that they have the properties of self-renewal, asymmetric cell division, resistance to apoptosis, independent growth, tumourigenicity and metastatic potential. A CSC origin for breast cancer can neatly explain both the heterogeneity of breast cancers and the relapse of the tumours after treatment. However, many reports on CSC in the breast are contradictory. There is variation with respect to how breast cancer stem cells should be identified, their characteristics and a possible lack of correlation between clinical outcome and breast cancer stem cell status of a tumour. These combined factors have made breast cancer stem cells a highly contentious issue. In this review, we highlight the progress in the analysis of cancer stem cells, with an emphasis on breast cancer.
- Full Text:
- Date Issued: 2009
- Authors: Lawson, Jessica C , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165057 , vital:41205 , DOI: 10.1007/s10549-009-0524-9
- Description: The cancer stem cell theory poses that cancers develop from a subset of malignant cells that possess stem cell characteristics and has been proposed to account for the development of a variety of malignancies, including breast cancer. These cancer stem cells (CSC) possess characteristics of both stem cells and cancer cells, in that they have the properties of self-renewal, asymmetric cell division, resistance to apoptosis, independent growth, tumourigenicity and metastatic potential. A CSC origin for breast cancer can neatly explain both the heterogeneity of breast cancers and the relapse of the tumours after treatment. However, many reports on CSC in the breast are contradictory. There is variation with respect to how breast cancer stem cells should be identified, their characteristics and a possible lack of correlation between clinical outcome and breast cancer stem cell status of a tumour. These combined factors have made breast cancer stem cells a highly contentious issue. In this review, we highlight the progress in the analysis of cancer stem cells, with an emphasis on breast cancer.
- Full Text:
- Date Issued: 2009