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Growing genetic and epidemiological evidence suggests a direct connection between the disruption of circadian rhythm and breast cancer. Moreover, the expression of several molecular components constituting the circadian clock machinery has been found to be modulated by estrogen-estrogen receptor α (E2-ERα) signaling in ERα-positive breast cancer cells. In this study, we investigated the regulation of CLOCK expression by ERα and its roles in cell proliferation. Immunohistochemical analysis of human breast tumor samples revealed high expression of CLOCK in ERα-positive breast tumor samples. Subsequent experiments using ERα-positive human breast cancer cell lines showed that both protein and mRNA levels of CLOCK were up-regulated by E2 and ERα. In these cells, E2 promoted the binding of ERα to the EREs (estrogen-response elements) of CLOCK promoter, thereby up-regulating the transcription of CLOCK. Knockdown of CLOCK attenuated cell proliferation in ERα-positive breast cancer cells. Taken together, these results demonstrated that CLOCK could be an important gene that mediates cell proliferation in breast cancer cells. [ABSTRACT FROM AUTHOR]

Abstract: SnO2, as an undercoat, has been recently applied on Ti substrate to prepare PbO2 anodes to improve the stability and electro-catalytic activity. In this work, we explored the electro-deposition of PbO2 on the Ti substrate with a Sb-doped SnO2 undercoat, from a traditional acidic nitrate solution. The morphology and microstructure of the PbO2 coatings were investigated by varying electro-deposition temperature and time. It is found that the Sb-doped SnO2 undercoat significantly promotes the electro-deposition process of PbO2. At a low electro-deposition temperature, a preferential crystallographic orientation is usually observed in the coatings, which exhibit a caterpillar-like morphology. At a higher deposition temperature, the PbO2 coatings display a more tightly packed pyramid-like morphology. The crystallite size increases with deposition temperature. Electrochemical performance of the deposited PbO2 largely depends on their morphologies and microstructures. It is suggested that deep reaction path, high porosity and good connectivity between crystallites play a synergic role in determining the electrochemical performance of the PbO2 coatings. [Copyright &y& Elsevier]