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: A review on current trends and future prospectives of electrospun biopolymeric nanofibers for biomedical applications

authors: Syed, Murtaza Haider

abstract: Electrospinning (ES) is considered the most advanced and robust method to make nanoscale materials named nanofibers (NFs) using various polymers. However, due to the hazardous and toxic nature of petroleum based polymers, the trend has shifted toward biopolymers. Conventional techniques to fabricate NFs are nonreproducible, require tedious procedures, and most incorporate toxicity to the final product. ES gained tremendous momentum as it is a crucial solution to the drawbacks of conventional methods. In recent years much prepondering research and review work has been done on ES applications. However, the present paper does not cliche the routine reporting format by review papers in recent years. Instead, it highlights the ignored significant parameters especially solvent related in current research responsible for underutilizing ES and new innovative ES methods. The current review signifies ES's crucial necessity for biomedical applications compared to conventional methods with similar biocomposites. A systematic review of the literature was done to correlate those parameters with the present work to find the gap in the existing literature. The present review is significant in providing a helpful tool to improve further the properties of the NFs biocomposites by ES methods. Significant missing correlations were identified, which, if considered in the future, can drastically improve the future of ES applications.

text: A review on current trends and future prospectives of electrospun biopolymeric nanofibers for biomedical applications Electrospinning (ES) is considered the most advanced and robust method to make nanoscale materials named nanofibers (NFs) using various polymers. However, due to the hazardous and toxic nature of petroleum based polymers, the trend has shifted toward biopolymers. Conventional techniques to fabricate NFs are nonreproducible, require tedious procedures, and most incorporate toxicity to the final product. ES gained tremendous momentum as it is a crucial solution to the drawbacks of conventional methods. In recent years much prepondering research and review work has been done on ES applications. However, the present paper does not cliche the routine reporting format by review papers in recent years. Instead, it highlights the ignored significant parameters especially solvent related in current research responsible for underutilizing ES and new innovative ES methods. The current review signifies ES's crucial necessity for biomedical applications compared to conventional methods with similar biocomposites. A systematic review of the literature was done to correlate those parameters with the present work to find the gap in the existing literature. The present review is significant in providing a helpful tool to improve further the properties of the NFs biocomposites by ES methods. Significant missing correlations were identified, which, if considered in the future, can drastically improve the future of ES applications.

year: 2023-10-10

title: Mahi Toi Skills in Contemporary Education, Training and Maori Development

authors: Joseph, Makarita Ngapine Tangitu

subjects: Kia mau ki nga taonga tuku iho o nga tupuna

abstract: Since the 1980’s, national investment in human capital and skill formation policy in education has been promoted as key to economic success and social inclusion. Social inclusion, however, is often expressed as helping citizens to become employable. Although employability is a key focus of skills formation and education policy, the context of the western ideologies that it derives from and caters to perpetuates the exclusion of mahi toi (arts and crafts) skills in education. Using a kaupapa Māori approach, two key informants who specialise and teach mahi toi skills, either rāranga (weaving) or pounamu (jade/greenstone), were interviewed. The aim was to get a better understanding of how these skills can contribute to personal, professional and Māori development in the 21st century, and to provide information indicating where and how these skills can be learnt, either through private training enterprises (PTE) or public tertiary educational institutions (TEI), thereby highlighting the value of teaching and learning rāranga and pounamu skills. Findings from analysing their pūrākau indicate that learning rāranga or pounamu skills can provide a foundation for believing in your potential, contribute to cultural identity, improve confidence and communication skills, help an individual be bestowed or acquire mana, offer a type of therapy, enhance career progression and professional identity, provide financial rewards and stability, and help with the revitalisation and transfer of cultural knowledge. Ultimately, it is concluded that mahi toi skills such as rāranga and pounamu can contribute to the development of an individual’s personal and professional lives, but also has benefits for the organisation where they become employed as well as extended whānau, hapū and iwi.

text: Mahi Toi Skills in Contemporary Education, Training and Maori Development Since the 1980’s, national investment in human capital and skill formation policy in education has been promoted as key to economic success and social inclusion. Social inclusion, however, is often expressed as helping citizens to become employable. Although employability is a key focus of skills formation and education policy, the context of the western ideologies that it derives from and caters to perpetuates the exclusion of mahi toi (arts and crafts) skills in education. Using a kaupapa Māori approach, two key informants who specialise and teach mahi toi skills, either rāranga (weaving) or pounamu (jade/greenstone), were interviewed. The aim was to get a better understanding of how these skills can contribute to personal, professional and Māori development in the 21st century, and to provide information indicating where and how these skills can be learnt, either through private training enterprises (PTE) or public tertiary educational institutions (TEI), thereby highlighting the value of teaching and learning rāranga and pounamu skills. Findings from analysing their pūrākau indicate that learning rāranga or pounamu skills can provide a foundation for believing in your potential, contribute to cultural identity, improve confidence and communication skills, help an individual be bestowed or acquire mana, offer a type of therapy, enhance career progression and professional identity, provide financial rewards and stability, and help with the revitalisation and transfer of cultural knowledge. Ultimately, it is concluded that mahi toi skills such as rāranga and pounamu can contribute to the development of an individual’s personal and professional lives, but also has benefits for the organisation where they become employed as well as extended whānau, hapū and iwi.

year: 2018