Bivalent chromatin: a developmental balancing act tipped in cancer.

Bivalent chromatin is defined by the co-occurrence of otherwise opposing H3K4me3 and H3K27me3 modifications and is typically located at unmethylated promoters of lowly transcribed genes. In embryonic stem cells, bivalent chromatin has been proposed to poise developmental genes for future activation, silencing or stable repression upon lineage commitment. Normally, bivalent chromatin is kept in tight balance in cells, in part through the activity of the MLL/COMPASS-like and Polycomb repressive complexes that deposit the H3K4me3 and H3K27me3 modifications, respectively, but also emerging novel regulators including DPPA2/4, QSER1, BEND3, TET1 and METTL14. In cancers, both the deregulation of existing domains and the creation of de novo bivalent states is associated with either the activation or silencing of transcriptional programmes. This may facilitate diverse aspects of cancer pathology including epithelial-to-mesenchymal plasticity, chemoresistance and immune evasion. Here, we review current methods for detecting bivalent chromatin and discuss the factors involved in the formation and fine-tuning of bivalent domains. Finally, we examine how the deregulation of chromatin bivalency in the context of cancer could facilitate and/or reflect cancer cell adaptation. We propose a model in which bivalent chromatin represents a dynamic balance between otherwise opposing states, where the underlying DNA sequence is primed for the future activation or repression. Shifting this balance in any direction disrupts the tight equilibrium and tips cells into an altered epigenetic and phenotypic space, facilitating both developmental and cancer processes.

Insights into Chinese Canadian culture: enablers and barriers for fruit and vegetable intake.

Background: Fruits and vegetables (F&V) play a vital role in promoting health and preventing diseases. Numerous studies have demonstrated the association between F&V consumption and reduced risks of cardiovascular disease, cancer, and mortality. Despite the high priority of public health in promoting F&V intake, Chinese immigrants in Canada often fall below national guidelines in their consumption. Understanding the factors influencing F&V intake in this community is crucial for developing effective interventions. Methods: This study used an applied ethnographic research approach to gain insight into the enablers and barriers that influence F&V intake among Chinese-Canadian adults in Richmond, BC. Semi-structured interviews and 'photovoice' group sessions were conducted to gather qualitative data from community participants and health care providers (HCPs). Results: The research identified four key themes: (1) Cultural differences around how vegetables are perceived, consumed and prepared; (2) Motivators and strategies for increasing vegetable and fruit intake; (3) Lack of culturally relevant dietary education and resources; and (4) Importance of value in vegetable/fruit-related decisions. Participants showed a strong preference for the traditional Eastern diet, with cost of food and lack of knowledge about Western vegetables acting as barriers to dietary diversity. The study also highlighted the need for culturally tailored educational resources to effectively promote F&V consumption. Conclusion: By adopting a multi-modal approach, incorporating both interviews and 'photovoice' sessions, this research provided comprehensive insights into the participants' perspectives and experiences related to F&V intake. Understanding these factors can guide the development of culturally appropriate interventions to increase F&V consumption among Chinese-Canadian adults in Richmond, BC, and potentially improve their overall health and well-being. Future studies should consider the heterogeneity within the Chinese immigrant population and target a more balanced representation of age groups to further enhance our understanding of F&V intake patterns in this community.