为了筛选靶向DNA连接酶Ⅳ的抑制剂以实现更有效的基因定点插入,采用分子对接技术筛选出与前期研究中靶向DNA连接酶Ⅳ的抑制剂SCR7作用类似的小分子化合物。筛选到与化合物库一致的nocodazole、Fisetin和Methylene blue 3个小分子化合物...为了筛选靶向DNA连接酶Ⅳ的抑制剂以实现更有效的基因定点插入,采用分子对接技术筛选出与前期研究中靶向DNA连接酶Ⅳ的抑制剂SCR7作用类似的小分子化合物。筛选到与化合物库一致的nocodazole、Fisetin和Methylene blue 3个小分子化合物,通过用MSTN基因T11位点序列截断的Firefly Luciferase荧光素酶报告载体结合CRISPR/Cas9-gRNA-T11载体共转细胞,并结合不同的小分子化合物处理。结果表明,没有用小分子化合物处理时,萤火虫荧光素酶被截断的位置发生NHEJ修复,不能得到大量有活性的萤火虫荧光素酶;经过小分子化合物处理,抑制了细胞内的NHEJ,提高了HDR效率,能得到大量有活性的萤火虫荧光素酶。使用nocodazole、Methylene blue和Fisetin处理后的萤火虫荧光素酶检测结果65256.3、53713和77058.3分别是SCR7处理后的萤火虫荧光素酶检测结果41905.3的1.6、1.3和1.8倍,是没有SCR7处理后的萤火虫荧光素酶检测结果10120的6.4、5.3和7.6倍。证明所用的筛选策略正确,所筛选出的小分子化合物是具有DNA ligaseⅣ抑制活性的抑制剂,为后续研究奠定了基础。展开更多
Nonhomologous DNA end joining （NHEJ） is the primary pathway for repair of double-strand DNA breaks in human cells and in multicellular eukaryotes. The causes of double-strand breaks often fragment the DNA at the sit...Nonhomologous DNA end joining （NHEJ） is the primary pathway for repair of double-strand DNA breaks in human cells and in multicellular eukaryotes. The causes of double-strand breaks often fragment the DNA at the site of damage, resulting in the loss of information there. NHEJ does not restore the lost information and may resect additional nucleotides during the repair process. The ability to repair a wide range of overhang and damage configurations reflects the flexibility of the nuclease, polymerases, and ligase of NHEJ. The flexibility of the individual components also explains the large number of ways in which NHEJ can repair any given pair of DNA ends. The loss of information locally at sites of NHEJ repair may contribute to cancer and aging, but the action by NHEJ ensures that entire segments of chromosomes are not lost.展开更多
Ovarian cancer(OC)is the sixth most common cancer and the seventh cause of death from cancer in women.The etiology and the ovarian carcinogenesis still need clarification although ovulation may be determinant due to i...Ovarian cancer(OC)is the sixth most common cancer and the seventh cause of death from cancer in women.The etiology and the ovarian carcinogenesis still need clarification although ovulation may be determinant due to its carcinogenic role in ovarian surface epithelium.The link between ovarian carcinogenesis and DNA repair is well established and it became clear that alterations in DNA damage response may affect the risk to develop OC.Polymorphisms are variations in the DNA sequence that exist in normal individuals of a population and are capable to change,among other mechanisms,the balance between DNA damage and cellular response.Consequently,genetic variability of the host has a great role in the development,progression and consequent prognosis of the oncologic patient as well as in treatment response.Standard treatment for OC patients is based on cytoreductive surgery,followed by chemotherapy with a platinum agent and a taxane.Although 80%of the patients respond to the first-line therapy,the development of resistance is common although the mechanisms underlying therapy failure remain mostly unknown.Because of their role in oncology,enzymes involved in the DNA repair pathways,like DNA Ligase IV(LIG4),became attractive study targets.It has been reported that variations in LIG4 activity can lead to a hyper-sensitivity to DNA damage,deregulation of repair and apoptosis mechanisms,affecting the susceptibility to cancer development and therapy response.To overcome resistance mechanisms,several investigations have been made and the strategy to target crucial molecular pathways,such as DNA repair,became one of the important areas in clinical oncology.This review aims to elucidate the link between DNA repair and OC,namely which concerns the role of LIG4 enzyme,and how genetic polymorphisms in LIG4 gene can modulate the activity of the enzyme and affect the ovarian carcinogenesis and treatment response.Moreover,we try to understand how LIG4 inhibition can be a potential contributor for the development of new cancer treatment strategies.展开更多
Cancer therapy with heavy ion bearns has now been progressed by America,Japan,Germany and some other countries.It becomes the most advanced and efficacious new cancer radiotherapy owing its high LET and RBE,low OER,es...Cancer therapy with heavy ion bearns has now been progressed by America,Japan,Germany and some other countries.It becomes the most advanced and efficacious new cancer radiotherapy owing its high LET and RBE,low OER,especialy forming Bragg peak at the end of the tracks of the charged particles.DNA展开更多
E3 ubiquitin ligases are a large family of proteins that catalyze the ubiquitination of many protein substrates for targeted degradation by the 26S proteasome.Therefore,E3 ubiquitin ligases play an essential role in a...E3 ubiquitin ligases are a large family of proteins that catalyze the ubiquitination of many protein substrates for targeted degradation by the 26S proteasome.Therefore,E3 ubiquitin ligases play an essential role in a variety of biological processes including cell cycle regulation,proliferation and apoptosis.E3 ubiquitin ligases are often found overexpressed in human cancers,including lung cancer,and their deregulation has been shown to contribute to cancer development.However,the lack of specific inhibitors in clinical trials is a major issue in targeting E3 ubiquitin ligases with currently only one E3 ubiquitin ligase inhibitor being tested in the clinical setting.In this review,we focus on E3 ubiquitin ligases that have been found deregulated in lung cancer.Furthermore,we discuss the processes in which they are involved and evaluate them as potential anti-cancer targets.By better understanding the mechanisms by which E3 ubiquitin ligases regulate biological processes and their exact role in carcinogenesis,we can improve the development of specific E3 ubiquitin ligase inhibitors and pave the way for novel treatment strategies for cancer patients.展开更多
文摘Nonhomologous DNA end joining （NHEJ） is the primary pathway for repair of double-strand DNA breaks in human cells and in multicellular eukaryotes. The causes of double-strand breaks often fragment the DNA at the site of damage, resulting in the loss of information there. NHEJ does not restore the lost information and may resect additional nucleotides during the repair process. The ability to repair a wide range of overhang and damage configurations reflects the flexibility of the nuclease, polymerases, and ligase of NHEJ. The flexibility of the individual components also explains the large number of ways in which NHEJ can repair any given pair of DNA ends. The loss of information locally at sites of NHEJ repair may contribute to cancer and aging, but the action by NHEJ ensures that entire segments of chromosomes are not lost.
基金Supported by Research Department of Portuguese League against Cancer(NRNorte)and Minister of Health of Portugal(CFICS-45/2007)
文摘Ovarian cancer(OC)is the sixth most common cancer and the seventh cause of death from cancer in women.The etiology and the ovarian carcinogenesis still need clarification although ovulation may be determinant due to its carcinogenic role in ovarian surface epithelium.The link between ovarian carcinogenesis and DNA repair is well established and it became clear that alterations in DNA damage response may affect the risk to develop OC.Polymorphisms are variations in the DNA sequence that exist in normal individuals of a population and are capable to change,among other mechanisms,the balance between DNA damage and cellular response.Consequently,genetic variability of the host has a great role in the development,progression and consequent prognosis of the oncologic patient as well as in treatment response.Standard treatment for OC patients is based on cytoreductive surgery,followed by chemotherapy with a platinum agent and a taxane.Although 80%of the patients respond to the first-line therapy,the development of resistance is common although the mechanisms underlying therapy failure remain mostly unknown.Because of their role in oncology,enzymes involved in the DNA repair pathways,like DNA Ligase IV(LIG4),became attractive study targets.It has been reported that variations in LIG4 activity can lead to a hyper-sensitivity to DNA damage,deregulation of repair and apoptosis mechanisms,affecting the susceptibility to cancer development and therapy response.To overcome resistance mechanisms,several investigations have been made and the strategy to target crucial molecular pathways,such as DNA repair,became one of the important areas in clinical oncology.This review aims to elucidate the link between DNA repair and OC,namely which concerns the role of LIG4 enzyme,and how genetic polymorphisms in LIG4 gene can modulate the activity of the enzyme and affect the ovarian carcinogenesis and treatment response.Moreover,we try to understand how LIG4 inhibition can be a potential contributor for the development of new cancer treatment strategies.
文摘Cancer therapy with heavy ion bearns has now been progressed by America,Japan,Germany and some other countries.It becomes the most advanced and efficacious new cancer radiotherapy owing its high LET and RBE,low OER,especialy forming Bragg peak at the end of the tracks of the charged particles.DNA
文摘E3 ubiquitin ligases are a large family of proteins that catalyze the ubiquitination of many protein substrates for targeted degradation by the 26S proteasome.Therefore,E3 ubiquitin ligases play an essential role in a variety of biological processes including cell cycle regulation,proliferation and apoptosis.E3 ubiquitin ligases are often found overexpressed in human cancers,including lung cancer,and their deregulation has been shown to contribute to cancer development.However,the lack of specific inhibitors in clinical trials is a major issue in targeting E3 ubiquitin ligases with currently only one E3 ubiquitin ligase inhibitor being tested in the clinical setting.In this review,we focus on E3 ubiquitin ligases that have been found deregulated in lung cancer.Furthermore,we discuss the processes in which they are involved and evaluate them as potential anti-cancer targets.By better understanding the mechanisms by which E3 ubiquitin ligases regulate biological processes and their exact role in carcinogenesis,we can improve the development of specific E3 ubiquitin ligase inhibitors and pave the way for novel treatment strategies for cancer patients.
