ABSTRACT
Doping is a recognized method for enhancing catalytic performance. The introduction of strains is a common consequence of doping, although it is often overlooked. Differentiating the impact of doping and strain on catalytic performance poses a significant challenge. In this study, Cu-doped Bi catalysts with substantial tensile strain are synthesized. The synergistic effects of doping and strain in bismuth result in a remarkable CO2RR performance. Under optimized conditions, Cu1/6-Bi demonstrates exceptional formate Faradaic efficiency (>95%) and maintains over 90% across a wide potential window of 900 mV. Furthermore, it delivers an industrial-relevant partial current density of -317 mA cm-2 at -1.2 VRHE in a flow cell, while maintaining its selectivity. Additionally, it exhibits exceptional long-term stability, surpassing 120 h at -200 mA cm-2. Through experimental and theoretical mechanistic investigations, it has been determined that the introduction of tensile strain facilitates the adsorption of *CO2, thereby enhancing the reaction kinetics. Moreover, the presence of Cu dopants and tensile strain further diminishes the energy barrier for the formation of *OCHO intermediate. This study not only offers valuable insights for the development of effective catalysts for CO2RR through doping, but also establishes correlations between doping, lattice strains, and catalytic properties of bismuth catalysts.
ABSTRACT
Secreted protein acidic and rich in cysteine (SPARC) is associated with the progression of numerous types of cancer. However, the role of SPARC in the progression of cervical cancer has not yet been adequately elucidated. In the current study, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry were employed to evaluate the mRNA and protein expression of SPARC in normal cervical tissue, cervical intraepithelial neoplasia (CIN) and cervical cancer. In addition, three epithelial-mesenchymal transition (EMT) markers (E-cadherin, N-cadherin and vimentin) were detected by immunohistochemistry in the same specimens, and an enzyme-linked immunosorbent assay was conducted to detect the serum levels of SPARC in patients with cervical neoplasia. In highly invasive subclones of human cervical carcinoma cells, HeLa-1 and SiHa-1, lentiviral transfections were performed and RT-qPCR and western blot were used to investigate the effects of downregulated EGF-containing fibulin-like extracellular matrix protein 1 on the expression of E-cadherin, N-cadherin and vimentin. The results revealed that, in cervical carcinoma tissue, SPARC expression was significantly upregulated in a manner that positively correlated with N-cadherin and vimentin expression, and negatively correlated with E-cadherin expression. SPARC overexpression and high serum levels were significantly associated with the progression of cervical cancer and adverse prognosis of cervical cancer patients. Downregulation of SPARC can markedly reduce the expression of N-cadherin and vimentin and increase the expression of E-cadherin. Thus, overexpression of SPARC is significantly associated with poor prognostic clinicopathological characteristics in cervical carcinoma, and may be important in EMT. The results of the current study suggest that SPARC may be a potential therapeutic option for individuals diagnosed with cervical carcinoma.
ABSTRACT
BACKGROUND: Secreted protein acidic and rich in cysteine (SPARC), a calcium-binding matricellular glycoprotein, is implicated in the progressions of some cancers. However, no information has been available to date regarding the function of SPARC in cervical cancer cell growth and metastasis. METHODS: In this study, we isolated and established high invasive subclones and low invasive subclones from human cervical cancer cell lines HeLa and SiHa by the limited dilution method. Real-time q-RT-PCR, Western Blot and ICC were performed to investigate SPARC mRNA and protein expressions in high invasive subclones and low invasive subclones. Then lentivirus vector with SPARC shRNA was constructed and infected the highly invasive subclones. Real-time q-RT-PCR, Western Blot and ICC were also performed to investigate the changes of SPARC expression after viral infection. In functional assays, effects of SPARC knockdown on the biological behaviors of cervical cancer cells were investigated. The mechanisms of SPARC in cervical cancer proliferation, apoptosis and invasion were also researched. RESULTS: SPARC was over-expressed in the highly invasive subclones compared with the low invasive subclones. Knockdown of SPARC significantly suppressed cervical cancer cell proliferation, and induced cell cycle arrest at the G1/G0 phase through the p53/p21 pathway, also caused cell apoptosis accompanied by the decreased ratio of Bcl-2/Bax, and inhibited cell invasion and metastasis accompanied by down-regulated MMP2 and MMP9 expressions and up-regulated E-cadherin expression. CONCLUSION: SPARC is related to the invasive phenotype of cervical cancer cells. Knockdown of SPARC significantly suppresses cervical cancer cell proliferation, induces cell apoptosis and inhibits cell invasion and metastasis. SPARC as a promoter improves cervical cancer cell growth and metastasis.
