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Objective To investigate the role and mechanism of the DNA helicase PIF1 in the proliferation of ovarian cancer cells and its response to DNA damage. Methods The relative expression of the PIF1 gene in normal ovarian tissue compared to ovarian cancer tissue, as well as the relationship between PIF1 expression and overall survival in ovarian cancer patients, was analyzed using the Gene Expression Profiling Interactive Analysis (GEPIA) and Kaplan-Meier Plotter public databases.PIF1 knockout ovarian cancer cells were established using CRISPR/Cas9 gene-editing technology.A retroviral vector overexpressing Rad51 recombinase was constructed, and then transfected into PIF1 knockout ES-2 ovarian cancer cells.Western blot analysis was used to determine the effects of PIF1 knockout and Rad51 overexpression in the transfected cells.Cell proliferation was assessed with cell counting, colony formation assay and CCK-8 assay.A total of 32 female BALB/c nude mice (6~8 weeks old, weighing 20~25 g) were randomly divided into ES-2 control group, ES-2 knockout group, OVCAR-3 control group, and OVCAR-3 knockout group, with 8 mice in each group.A mouse xenograft model was established to assess the in vivo proliferative capacity of ovarian cancer cells.Apoptotic rate and cell cycle were assessed using flow cytometry.The senescence of ovarian cancer cells was evaluated through a β-galactosidase activity assay.Western blotting and immunofluorescence assay were applied to determine the changes in phosphorylated histone H2AX (γ-H2AX) protein were measured with to evaluate the effects of PIF1 knockout and Rad51 overexpression on DNA damage and to observe the localization of PIF1 and Rad51 in ovarian cancer cells. Results The analysis of public databases revealed that PIF1 overexpression was negatively correlated with the overall survival of patients (P < 0.001), and PIF1 was found to be overexpressed in the ovarian cancer tissues than the normal ovarian tissues (P < 0.05).CRISPR/Cas9-mediated knockout of PIF1 significantly inhibited the proliferation (P < 0.01) and clonogenic ability (P < 0.001) of ovarian cancer cells, which was also validated in mouse model (P < 0.05).Flow cytometry indicated that PIF1 knockout promoted apoptosis (P < 0.01) and induced cell cycle arrest (P < 0.01) in ovarian cancer cells.In addition, β-galactosidase activity assay demonstrated that PIF1 knockout enhanced cellular senescence (P < 0.001).Western blot and CCK-8 assays further revealed that PIF1 knockout increased the expression of γ-H2AX protein (P < 0.05) and suppressed the proliferative capacity of ovarian cancer cells following cisplatin treatment (P < 0.05).In PIF1 knockout ovarian cancer cells, Rad51 expression was diminished.However, overexpression of Rad51 in PIF1-deficient cells restored PIF1 expression, decreased γ-H2AX protein level (P < 0.05), and rescued cell proliferation (P < 0.01).Immunofluorescence assay demonstrated that EGFP-PIF1 and Rad51 were co-localized in the nucleus. Conclusion PIF1 and Rad51 collaboratively regulate DNA damage and cell proliferation in ovarian cancer cells.

Black phosphorus (BP) shows great potential in electronic and optoelectronic applications; however, maintaining the stable performance of BP devices over temperature is still challenging. Here, a novel BP field-effect transistor (FET) fabricated on the atomic layer deposited AlN/SiO2/Si substrate is demonstrated. Electrical measurement results show that BP FETs on the AlN substrate possess superior electrical performance compared with those fabricated on the conventional SiO2/Si substrate. It exhibits a large on-off current ratio of 5 × 108, a low subthreshold swing of

The synapse is one of the fundamental elements in human brain performing functions such as learning, memorizing, and visual processing. The implementation of synaptic devices to realize neuromorphic computing and sensing tasks is a key step to artificial intelligence, which, however, has been bottlenecked by the complex circuitry and device integration. We report a high-performance charge-trapping memory synaptic device based on two-dimensional (2D) MoS2 and high-k Ta2O5–TiO2 (TTO) composite to build efficient and reliable neuromorphic system, which can be modulated by both electrical and optical stimuli. Significant and essential synaptic behaviors including short-term plasticity, long-term potentiation, and long-term depression have been emulated. Such excellent synaptic behaviors originated from the good nonvolatile memory performance due to the high density of defect states in the engineered TTO composite. The 2D synaptic device also exhibits effective switching by incident light tuning, which further enables pattern recognition with accuracy rate reaching 100%. Such experimental demonstration paves a robust way toward a multitask neuromorphic system and opens up potential applications in future artificial intelligence and sensing technology.

The fast-developing information technology has imposed an urgent need for effective solutions to overcome the limitations of integration density in chips with smaller size but higher performance. van der Waals heterojunctions built with two-dimensional (2D) semiconductors have been widely studied due to their 2D nature, and their unique electrical and photoelectronic properties are quite attractive in realizing multifunctional devices toward multitask applications. In this work, black phosphorus (BP)/MoS2 heterojunctions have been used to build electronic devices with various functionalities. A p-n diode is achieved based on the vertically stacked BP/MoS2 heterojunction exhibiting an ideal factor of 1.59, whereas a laterally stacked BP/MoS2 heterojunction is implemented to fabricate a photodetector that shows a photodetection responsivity of 2000 mA/W at a wavelength of 1300 nm. Furthermore, a ternary inverter has been realized using a BP field-effect transistor in-series with a lateral BP/MoS2 heterojunction. Such results have unambiguously demonstrated the superiority of BP/MoS2 heterojunction in realizing multiple functionalities and have offered a new pathway for the design and engineering of future circuitry and device integration based on novel 2D semiconductors.