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Background: Although radiotherapy has improved local control in esophageal squamous cell carcinoma (ESCC), a considerable number of patients still experience relapse due to resistance. In this study, we aimed to evaluate the effects of cetuximab on radiosensitivity in two ESCC cell lines (ECA109 and TE‐13) and to investigate their underlying mechanisms. Methods: Cells were pretreated with or without cetuximab before irradiation. The MTT assay and clonogenic survival assay were performed to evaluate cell viability and radiosensitivity. Flow cytometry was performed to analyze cell cycle distribution and apoptosis. The γH2AX foci were counted to determine cellular DNA‐repairing capacity via immunofluorescence assay. The phosphorylation of key molecules involved in the epidermal growth factor receptor (EGFR) signaling pathway and DNA double‐strand break (DSB) repair were measured by western blot. Results: Cetuximab alone was not sufficient to suppress cell viability, but significantly enhanced radiation‐induced inhibition of clonogenic survival in ECA109 and TE‐13. The radiation sensitivity enhancement ratio (SER) was 1.341 and 1.237 for ECA109 and TE‐13, respectively. ESCC cells treated with cetuximab were arrested at the G2/M phase in response to radiation. No significant increase in apoptotic rate was observed in irradiated cells that were treated with cetuximab. The average number of γH2AX foci increased in the combination group (cetuximab and radiation). Cetuximab suppressed phosphorylation of EGFR and downstream ERK, but had no significant effect on AKT. Conclusions: These results indicate the potential for use of cetuximab as an effective radiosensitizer in ESCC. Cetuximab promotes G2/M cycle arrest and reduces DSB repair, as well as inhibiting EGFR and downstream ERK pathways in ESCC. [ABSTRACT FROM AUTHOR]

Speciation is often accompanied by frequent gene exchanges, which have been gradually recognized as a common phenomenon in nature. Although gene flow may influence different reproductive isolations, the specific mechanism of the process still requires more experimental evidence, especially in hybrid populations that have no significant differentiation and isolation. To address this challenge, this study aims to elucidate the underlying mechanisms of sympatry and parapatry in related species. Three sclerophyllous oaks (Quercus spinosa, Quercus aquifolioides and Quercus rehderiana), which are mainly distributed in the sympatry/parapatry of the East Himalaya–Hengduan Mountains and adjacent regions, were used to explore the population dynamics and evolutionary history. Based on 12,420 genome‐wide single nucleotide polymorphism datasets, gene flow detection showed that the three species did not present any obvious genetic barriers. Evolutionary analysis indicated that the three species diverged during the Tertiary Period, and no migration events occurred in the early stages of species divergence. Combined with the data of 19 ecological factors, geological movements and climatic turbulence caused the rapid radiated differentiation of the three species during the Neocene, and similar selective pressures resulted in the same evolutionary pattern based on demographic history analysis. In addition, the predicted niche occupancy profiles and Generalized Dissimilarity Modelling revealed that the three species occupied distinct niches and had significant differences in ecological adaptation, which may explain the specific morphological characteristics of the different species. Therefore, we believe that the populations of the three related species underwent adaptive evolution in different habitats during the early stages of divergence. This study provides new experimental evidence of the formation patterns of parallel speciation. [ABSTRACT FROM AUTHOR]

Gynostemma pentaphyllum (Thunb.) Makino is a perennial creeping herbaceous plant in the family Cucurbitaceae, which has great medicinal value and commercial potential, but urgent conservation efforts are needed due to the gradual decreases and fragmented distribution of its wild populations. Here, we report the high-quality diploid chromosome-level genome of G. pentaphyllum obtained using a combination of next-generation sequencing short reads, Nanopore long reads, and Hi-C sequencing technologies. The genome is anchored to 11 pseudo-chromosomes with a total size of 608.95 Mb and 26 588 predicted genes. Comparative genomic analyses indicate that G. pentaphyllum is estimated to have diverged from Momordica charantia 60.7 million years ago, with no recent whole-genome duplication event. Genomic population analyses based on genotyping-by-sequencing and ecological niche analyses indicated low genetic diversity but a strong population structure within the species, which could classify 32 G. pentaphyllum populations into three geographical groups shaped jointly by geographic and climate factors. Furthermore, comparative transcriptome analyses showed that the genes encoding enzyme involved in gypenoside biosynthesis had higher expression levels in the leaves and tendrils. Overall, the findings obtained in this study provide an effective molecular basis for further studies of demographic genetics, ecological adaption, and systematic evolution in Cucurbitaceae species, as well as contributing to molecular breeding, and the biosynthesis and biotransformation of gypenoside. [ABSTRACT FROM AUTHOR]

Gynostemma microspermum C. Y. Wu et S. K. Chen is an endemic creeping herbaceous species mainly distributed in dense forests on limestone in northwestern China. Here, the complete chloroplast genome sequence of G. microspermum was obtained by Illumina pair-end sequencing. The circular complete chloroplast genome of G. microspermum is 158,692 bp in length and contains a large single copy region (87,452 bp), a small single copy region (19,068 bp) and two short inverted repeat regions (26,086 bp). The genome sequence encodes 133 genes including 87 protein-coding genes, 37 transfer RNA genes, 8 ribosomal RNA genes and 1 pseudogene. The maximum likelihood (ML) phylogeny estimation shows that G. microspermum is sister to all other analyzed species of the genus Gynostemma with high bootstrap support. [ABSTRACT FROM AUTHOR]

Mesenchymal stem cells (MSCs) primarily secrete physiologically functional exosomes via paracrine effects that act on various adjacent and distant cells, thus exerting their therapeutic effects. In recent years, hypoxic preconditioning, as a novel MSC culture mode, has emerged as a research hotspot. Many previous studies have shown the role and underlying regulatory mechanisms of hypoxic preconditioning in various diseases, which has provided sufficient reference materials for the MSC research field. Therefore, this review summarizes the progress in application of hypoxia-preconditioned MSC-derived exosomes that substantially increases and improves the biological activity of specific molecules, such as microRNA., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Zhuo, Chen and Zhao.)