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The cell of origin of colon cancer is typically thought to be the resident somatic stem cells, which are immortal and escape the continual cellular turnover characteristic of the intestinal epithelium. However, recent studies have identified certain conditions in which differentiated cells can acquire stem-like properties and give rise to tumors. Defining the origins of tumors will inform cancer prevention efforts as well as cancer therapies, as cancers with distinct origins often respond differently to treatments. We report here a new condition in which tumors arise from the differentiated intestinal epithelium. Inactivation of the differentiation-promoting transcription factor SMAD4 in the intestinal epithelium was surprisingly well tolerated in the short term. However, after several months, adenomas developed with characteristics of activated WNT signaling. Simultaneous loss of SMAD4 and activation of the WNT pathway led to dedifferentiation and rapid adenoma formation in differentiated tissue. Transcriptional profiling revealed acquisition of stem cell characteristics, and colabeling indicated that cells expressing differentiated enterocyte markers entered the cell cycle and reexpressed stem cell genes upon simultaneous loss of SMAD4 and activation of the WNT pathway. These results indicate that SMAD4 functions to maintain differentiated enterocytes in the presence of oncogenic WNT signaling, thus preventing dedifferentiation and tumor formation in the differentiated intestinal epithelium. This work identifies a mechanism through which differentiated cells prevent tumor formation by suppressing oncogenic plasticity. .

Psychological well-being is an important indicator of well-being and has been found to be associated with a multitude of positive life outcomes. Using data collected from 1,871 Chinese college students from September 23 to October 5, 2020, this study examined students' psychological well-being during the COVID-19 pandemic and investigated how resilience and pandemic-related environmental stress may affect psychological well-being. Results showed that resilience had strong positive effects on psychological well-being during the pandemic. Meanwhile, environmental stress had a moderate effect and marginally reduced psychological well-being. The magnitudes of the estimates suggested that increasing resilience can effectively buffer the negative effect of environmental stress on psychological well-being.

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Internationally, human service professionals, including social workers, experience high burnout and turnover rates. Despite the recent and rapid development of contemporary social work in China, Chinese social workers similarly experience significant rates of burnout. Therefore, there is a need to investigate the factors that contribute to social work burnout. This study applied the job demands and resources (JD-R) model to examine the effects of JD-R on burnout in social workers (n = 897) from Chengdu, China, and whether these relations are mediated by state mindfulness. Structural equation modeling results supported the previously hypothesized dual process by which JD-R affect burnout, specifically in a sample of social workers in China. Job demands (JD) were positively associated with burnout, while job resources (JR) were negatively associated with burnout. These relations were partially mediated by state mindfulness. JR had a strong, positive direct effect on mindfulness (β = 0.38), and its total effect on burnout was high (β = −0.56). Meanwhile, JD had a slight negative direct effect on mindfulness (β = −0.09), and its total effect on burnout was 0.42. The results suggest that the implementation of mindfulness-based interventions for social workers can potentially mitigate the effect of JD on burnout, as well as increase the effect of JR on burnout.