title: Differential effects of organic versus inorganic selenium species on BRCA1-mutated and non-mutated breast cancer cell lines

authors: Ko, Yi-An (Annie)

subjects: Selenium

abstract: Selenium (Se) is an important trace element required for maintaining human health. Small amounts of Se has a chemoprotective effect to protect cells from oxidative damage, but higher dosages can introduce damage to DNA, and trigger apoptosis. The effect of Se is dependent on the dosage and chemical form of Se. Previous studies suggest inorganic Se in the form of selenite is more potent than the organic Se form, methylseleninic acid (MSA). The damaging effect of Se has been utilised to combine with chemotherapy drugs to synergistically kill cancer cells. Interestingly, more recent studies suggest that supranutritional dosage of Se can kill tumorous cells while leaving the normal healthy cells unharmed. BRCA1 is a tumour-suppressor gene which functions in sensing and repairing DNA damage. Mutations in BRCA1 are highly associated with breast cancer. Previous epidemiological studies suggest that a patient with BRCA1 mutations appears to be more sensitive to Se supplements.

The first objective of this research is to evaluate the interaction of Se dose and chemical form in BRCA1-mutated and non-mutated breast cancer cells in vitro. We applied Se (MSA and selenite) to two commercially-available BRCA1 and two non-BRCA1 mutated breast cancer cell lines. We hypothesised that breast cancer cells with a BRCA1 mutation are more sensitive to DNA damage and death from Se treatment, especially with the inorganic form. Se sensitivity was measured by examining DNA damage and cell viability with the comet assay and the colorimetric MTT assay, respectively. Based on the results from the first objective, the second aim was to examine the combined effect of Se with the chemotherapy drug, cisplatin, and evaluate the synergistic anti-tumour effect on the breast cancer cell lines. The viability after drug exposure was measured with MTT assay. Lastly, we also validated a new technique called Long run real-time PCR (Lord-qPCR) for quantifying DNA damage based on the amplification efficiency in real-time PCR. Se genotoxicity was again tested with this method and the results were compared to the conventional comet assay. 

Comparison of the comet assays between two BRCA1-mutated breast cell lines (MDA-MB-231 and Sum149pt) and two non-BRCA1-mutated breast cancer cell lines (MCF-7 and MDA-MB-231) showed significantly (p=0.01) greater DNA damage in the cells with BRCA1 mutation for each Se compound. The IC50 values for selenite and MSA, obtained with the MTT assay, were lower in BRCA1-mutated cells than the non-BRCA1-mutated cells. The outcome of the combined treatment with a physiological level of cisplatin and selenite/MSA did not show any synergistic cell inhibition on either BRCA1-mutated or non-mutated breast cancer cell lines. Interestingly, cisplatin at the physiological level, appeared to be less potent than 2 μM of Se treatment. Lastly, Lord-qPCR in comparison to the comet assay is indeed much less labour-intensive. The Se genotoxicity results from Lord-PCR followed the overall trend demonstrated in the comet assay. Surprisingly, DNA lesions predicted from mitochondrial DNA appear to be insignificantly greater than nuclear DNA. However, one drawback of the Lord-qPCR is that the reproducibility is much lower than comet assay, and may therefore require further optimisation.

text: Differential effects of organic versus inorganic selenium species on BRCA1-mutated and non-mutated breast cancer cell lines Selenium (Se) is an important trace element required for maintaining human health. Small amounts of Se has a chemoprotective effect to protect cells from oxidative damage, but higher dosages can introduce damage to DNA, and trigger apoptosis. The effect of Se is dependent on the dosage and chemical form of Se. Previous studies suggest inorganic Se in the form of selenite is more potent than the organic Se form, methylseleninic acid (MSA). The damaging effect of Se has been utilised to combine with chemotherapy drugs to synergistically kill cancer cells. Interestingly, more recent studies suggest that supranutritional dosage of Se can kill tumorous cells while leaving the normal healthy cells unharmed. BRCA1 is a tumour-suppressor gene which functions in sensing and repairing DNA damage. Mutations in BRCA1 are highly associated with breast cancer. Previous epidemiological studies suggest that a patient with BRCA1 mutations appears to be more sensitive to Se supplements.

The first objective of this research is to evaluate the interaction of Se dose and chemical form in BRCA1-mutated and non-mutated breast cancer cells in vitro. We applied Se (MSA and selenite) to two commercially-available BRCA1 and two non-BRCA1 mutated breast cancer cell lines. We hypothesised that breast cancer cells with a BRCA1 mutation are more sensitive to DNA damage and death from Se treatment, especially with the inorganic form. Se sensitivity was measured by examining DNA damage and cell viability with the comet assay and the colorimetric MTT assay, respectively. Based on the results from the first objective, the second aim was to examine the combined effect of Se with the chemotherapy drug, cisplatin, and evaluate the synergistic anti-tumour effect on the breast cancer cell lines. The viability after drug exposure was measured with MTT assay. Lastly, we also validated a new technique called Long run real-time PCR (Lord-qPCR) for quantifying DNA damage based on the amplification efficiency in real-time PCR. Se genotoxicity was again tested with this method and the results were compared to the conventional comet assay. 

Comparison of the comet assays between two BRCA1-mutated breast cell lines (MDA-MB-231 and Sum149pt) and two non-BRCA1-mutated breast cancer cell lines (MCF-7 and MDA-MB-231) showed significantly (p=0.01) greater DNA damage in the cells with BRCA1 mutation for each Se compound. The IC50 values for selenite and MSA, obtained with the MTT assay, were lower in BRCA1-mutated cells than the non-BRCA1-mutated cells. The outcome of the combined treatment with a physiological level of cisplatin and selenite/MSA did not show any synergistic cell inhibition on either BRCA1-mutated or non-mutated breast cancer cell lines. Interestingly, cisplatin at the physiological level, appeared to be less potent than 2 μM of Se treatment. Lastly, Lord-qPCR in comparison to the comet assay is indeed much less labour-intensive. The Se genotoxicity results from Lord-PCR followed the overall trend demonstrated in the comet assay. Surprisingly, DNA lesions predicted from mitochondrial DNA appear to be insignificantly greater than nuclear DNA. However, one drawback of the Lord-qPCR is that the reproducibility is much lower than comet assay, and may therefore require further optimisation.

year: 2016

title: Examining work-family practice use and employee attitudes in a New Zealand local government organisation

authors: Haar, Jarrod M.

abstract: Work-family practices have proliferated in response to major changes in the workplace, including the increased participation rates of women and mothers, the rise in dual-career families and single parent families, and growth in the elderly population. These changes are seen as providing employees help in balancing work and family commitments. Work-family policies are purported to offer benefits to both employers and employees, for example reduced turnover, increased organisational commitment and greater job satisfaction.

The major focus of the present study was employee use of multiple work-family policies, as the majority of the work-family literature focuses upon single practices. The present study sought to examine the relationship between work-family practice use and work-family conflict, to determine whether work-family practices link with conflict. Also, in response to a failure of the literature in explaining the link between work-family policy use and employee attitudes, the present study used social exchange theory and the norm of reciprocity to better explain the relationship. The present study also use a set of organisational justice theories to examine perceptions of the fairness of work-family policies, and the link these perceptions may have with general employee attitudes. Also, for exploring work-family backlash, where the distribution of rewards suggests work-family non-users may hold negative attitudes compared to users.

A single local government organisation, with 203 employees, was the focus of this study. Surveys were distributed at two distinct time periods to reduce common method variance. A total of 100 paired survey responses were received. Findings supported a positive relationship between work-family practices and conflict between work and home, in both directions. Additionally, work → family conflict was associated with decreased job satisfaction and increased work strain. Findings also indicated that work-family practice use predicted work-family specific attitudes but not attitudes towards the job and organisation. Work-family practice use and perceived benefits of work-family programmes predicted fairness perceptions, however, fairness perceptions failed to predict attitudes towards the organisation and job. Lastly, there was no evidence of a work-family backlash, with users and non-users holding similar attitudes towards the work-family programmes, organisation and job.

Implications include the need for examining the causal nature of the work-family practice and conflict relationship, caution regarding the assumption that work-family policies are automatically beneficial, and encouragement for organisations to proactively test their work-family programmes. Lastly, the lack of a work-family backlash suggests media sensationalism, and, therefore, as non-users are not likely to hold negative attitudes towards the organisation, work-family backlash should not be seen as discouraging organisational adoption of work-family programmes.

Contributions of this research include the examination of multiple work-family practices, which is rare, and the elucidation of the work-family conflict – work-family practice use relationship, which is poorly understood. Theorising the influence that work-family practices have upon employee attitudes is another contribution. While the findings indicated no significant link between general attitudes and practice use, this might highlight a methodological limitation in examining practice use, rather than practice value or frequency of use. Lastly, this thesis indicates that work-family practices do link in multiple ways with employee attitudes under multiple theoretical approaches.

text: Examining work-family practice use and employee attitudes in a New Zealand local government organisation Work-family practices have proliferated in response to major changes in the workplace, including the increased participation rates of women and mothers, the rise in dual-career families and single parent families, and growth in the elderly population. These changes are seen as providing employees help in balancing work and family commitments. Work-family policies are purported to offer benefits to both employers and employees, for example reduced turnover, increased organisational commitment and greater job satisfaction.

The major focus of the present study was employee use of multiple work-family policies, as the majority of the work-family literature focuses upon single practices. The present study sought to examine the relationship between work-family practice use and work-family conflict, to determine whether work-family practices link with conflict. Also, in response to a failure of the literature in explaining the link between work-family policy use and employee attitudes, the present study used social exchange theory and the norm of reciprocity to better explain the relationship. The present study also use a set of organisational justice theories to examine perceptions of the fairness of work-family policies, and the link these perceptions may have with general employee attitudes. Also, for exploring work-family backlash, where the distribution of rewards suggests work-family non-users may hold negative attitudes compared to users.

A single local government organisation, with 203 employees, was the focus of this study. Surveys were distributed at two distinct time periods to reduce common method variance. A total of 100 paired survey responses were received. Findings supported a positive relationship between work-family practices and conflict between work and home, in both directions. Additionally, work → family conflict was associated with decreased job satisfaction and increased work strain. Findings also indicated that work-family practice use predicted work-family specific attitudes but not attitudes towards the job and organisation. Work-family practice use and perceived benefits of work-family programmes predicted fairness perceptions, however, fairness perceptions failed to predict attitudes towards the organisation and job. Lastly, there was no evidence of a work-family backlash, with users and non-users holding similar attitudes towards the work-family programmes, organisation and job.

Implications include the need for examining the causal nature of the work-family practice and conflict relationship, caution regarding the assumption that work-family policies are automatically beneficial, and encouragement for organisations to proactively test their work-family programmes. Lastly, the lack of a work-family backlash suggests media sensationalism, and, therefore, as non-users are not likely to hold negative attitudes towards the organisation, work-family backlash should not be seen as discouraging organisational adoption of work-family programmes.

Contributions of this research include the examination of multiple work-family practices, which is rare, and the elucidation of the work-family conflict – work-family practice use relationship, which is poorly understood. Theorising the influence that work-family practices have upon employee attitudes is another contribution. While the findings indicated no significant link between general attitudes and practice use, this might highlight a methodological limitation in examining practice use, rather than practice value or frequency of use. Lastly, this thesis indicates that work-family practices do link in multiple ways with employee attitudes under multiple theoretical approaches.

year: 2002

title: Mana Wahine Geographies: Spiritual, Spatial and Embodied Understandings of Papatūānuku

authors: Simmonds, Naomi Beth

subjects: Mana wahine

abstract: This thesis is a theoretical and empirical exploration of Māori women's knowledges and understandings of Papatūānuku in contemporary Aotearoa. The primary focus of this research is on the complexities, connections, and contradictions of Māori women's embodied relationships with the spaces of Papatūānuku - spaces that are simultaneously material, discursive, symbolic, and spiritual. In doing so, I displace the boundaries between coloniser/colonised, self/other, rational/irrational and scientific/spiritual. I demonstrate that Māori women's colonised realities produce multiple, complex and hybrid understandings of Papatūānuku. 

This thesis has three main strands. The first is theoretical. I offer mana wahine (Māori feminist discourses) as another perspective for geography that engages with the complex intersections of colonisation, race and gender. A mana wahine geography framework is a useful lens through which to explore the complexities of Māori women's relationships to space and place. This framework contributes to, and draws together, feminist geographies and Māori and indigenous academic scholarship.

Autobiographical material is woven with joint and individual semi-structured in-depth interviews conducted with nine Māori women in the Waikato region. The second strand, woven into this thesis, is a critical examination of the colonisation of Māori women's spiritual and embodied relationships to Papatūānuku. The invisibility of Māori women's knowledges in dominant conceptualisations of mythology, tikanga and wairua discourses is not a harmless omission rather it contains a political imperative that maintains the hegemony of colonialism and patriarchy. I argue that to understand further Māori women's relationships to space and place an examination of wairua discourses is necessary.

The third strand reconfigures embodied and spatial conceptualisations of Papatūānuku. Māori women's maternal bodies are intimately tied to Papatūānuku in a way that challenges the oppositional distinctions between mind/body and biology/social inscription. Māori women's maternal bodies (and the representation of them in te reo Māori) are constructed by, and in turn, construct Papatūānuku. Furthermore, women's spatial relationship to tūrangawaewae, home space and wider environmental concerns demonstrates the co-constitution of subjectivities, bodies and space/place. 

My hope is that this thesis will add to geographical literature by addressing previously ignored knowledges and that it will contribute to indigenous scholarship by providing a spatial perspective.

text: Mana Wahine Geographies: Spiritual, Spatial and Embodied Understandings of Papatūānuku This thesis is a theoretical and empirical exploration of Māori women's knowledges and understandings of Papatūānuku in contemporary Aotearoa. The primary focus of this research is on the complexities, connections, and contradictions of Māori women's embodied relationships with the spaces of Papatūānuku - spaces that are simultaneously material, discursive, symbolic, and spiritual. In doing so, I displace the boundaries between coloniser/colonised, self/other, rational/irrational and scientific/spiritual. I demonstrate that Māori women's colonised realities produce multiple, complex and hybrid understandings of Papatūānuku. 

This thesis has three main strands. The first is theoretical. I offer mana wahine (Māori feminist discourses) as another perspective for geography that engages with the complex intersections of colonisation, race and gender. A mana wahine geography framework is a useful lens through which to explore the complexities of Māori women's relationships to space and place. This framework contributes to, and draws together, feminist geographies and Māori and indigenous academic scholarship.

Autobiographical material is woven with joint and individual semi-structured in-depth interviews conducted with nine Māori women in the Waikato region. The second strand, woven into this thesis, is a critical examination of the colonisation of Māori women's spiritual and embodied relationships to Papatūānuku. The invisibility of Māori women's knowledges in dominant conceptualisations of mythology, tikanga and wairua discourses is not a harmless omission rather it contains a political imperative that maintains the hegemony of colonialism and patriarchy. I argue that to understand further Māori women's relationships to space and place an examination of wairua discourses is necessary.

The third strand reconfigures embodied and spatial conceptualisations of Papatūānuku. Māori women's maternal bodies are intimately tied to Papatūānuku in a way that challenges the oppositional distinctions between mind/body and biology/social inscription. Māori women's maternal bodies (and the representation of them in te reo Māori) are constructed by, and in turn, construct Papatūānuku. Furthermore, women's spatial relationship to tūrangawaewae, home space and wider environmental concerns demonstrates the co-constitution of subjectivities, bodies and space/place. 

My hope is that this thesis will add to geographical literature by addressing previously ignored knowledges and that it will contribute to indigenous scholarship by providing a spatial perspective.

year: 2009