Biology subjects

Bangi, E.

Publications and source records attributed to Bangi, E..

3 recordsLinked to original sources

bioRxiv2023

Senescent cells and macrophages cooperate through a multikinase signaling network to promote intestinal transformation in Drosophila.

Cellular senescence is a conserved biological process essential for embryonic development, tissue remodeling, repair, and a key regulator of aging. Senescence also plays a crucial role in cancer, though this role can be tumor-suppressive or tumor-promoting, depending on the genetic context and the microenvironment. The highly heterogeneous, dynamic, and context-dependent nature of senescence-associated features and the relatively small numbers of senescent cells in tissues makes in vivo mechanistic studies of senescence challenging. As a result, which senescence-associated features are observed in which disease contexts and how they contribute to disease phenotypes remain largely unknown. Similarly, the specific mechanisms by which various senescence-inducing signals are integrated in vivo to induce senescence and why some cells become senescent while their immediate neighbors do not are unclear. Here, we identify a small number of cells that exhibit multiple features of senescence in a genetically complex model of intestinal transformation we recently established in the developing Drosophila larval hindgut epithelium. We demonstrate that these cells emerge in response to concurrent activation of AKT, JNK, and DNA damage response pathways within transformed tissue. Eliminating senescent cells, genetically or by treatment with senolytic compounds, reduces overgrowth and improves survival. We find that this tumor-promoting role is mediated by Drosophila macrophages recruited to the transformed tissue by senescent cells, which results in non-autonomous activation of JNK signaling within the transformed epithelium. These findings emphasize complex cell-cell interactions underlying epithelial transformation and identify senescent cell-macrophage interactions as a potential druggable node in cancer. One sentence summary: Interactions between transformed senescent cells and macrophages drive tumorigenesis.

cancer biology↗

bioRxiv2022

Disruptions in cell fate decisions and transformed enteroendocrine cells drive intestinal tumorigenesis in Drosophila.

Most epithelial tissues are maintained by stem cells that produce the different cell lineages required for proper tissue function. Constant communication between different cell types that make up a tissue is essential to ensure that all cell lineages are produced at appropriate numbers and to mount regenerative responses to injury, infection, and other environmental stresses. Cancer-driving alterations change the intrinsic properties of transformed cells and disrupt stem cell regulation, cell fate decisions, and cell-cell communication within transformed tissue. However, mechanisms by which these processes are disrupted and co-opted to support tumorigenesis are not well understood. Here, we report a novel genetic platform, PromoterSwitch, that allows targeting of genetic manipulations to a small subset of cells of any tissue or cell type of interest and all their subsequent progeny. We use this technology to generate large, transformed clones derived from individual stem/progenitor cells in the adult Drosophila intestine. We show that cancer-driving genetic alterations representing common colon tumor genome landscapes drive disruptions in cell fate decisions within transformed clones and changes in the relative abundance of different intestinal cell lineages. We also uncover a critical, context-dependent role for the differentiated, hormone-producing enteroendocrine (EE) cells in the growth and maintenance of transformed clones. Our analysis in different genetic contexts provides insights into how the intrinsic properties of transformed cells --dictated by the genetic alterations they carry-- determine their response to their environment and dependence on niche signals. A better mechanistic understanding of disruptions of cell-cell communication, stem cell regulation, and cell fate decisions within tumors could reveal novel vulnerabilities and druggable regulatory nodes that can be exploited for therapy. Understanding how tissues respond to the emergence of cells with cancer-driving genetic alterations also provides insights into stem cell biology and epithelial homeostasis.

cancer biology↗

bioRxiv2022

A targeted genetic modifier screen in Drosophila uncovers vulnerabilities in a genetically complex model of colon cancer

Kinases are key regulators of cellular signal transduction pathways. Many diseases including cancer are associated with global alterations in protein phosphorylation networks, as a result, kinases are frequent targets of drug discovery efforts. However, target identification and assessment, a critical step in targeted drug discovery which involves identifying essential genetic mediators of disease phenotypes, can be challenging in complex, heterogeneous diseases like cancer where multiple concurrent genomic alterations are common. Drosophila is a particularly useful genetic model system to identify novel regulators of biological processes through unbiased genetic screens. Here, we report two classic genetic modifier screens focusing on the Drosophila kinome to identify kinase regulators in two different backgrounds: KRAS TP53 PTEN APC, a multigenic cancer model that targets four genes recurrently mutated in human colon tumors and KRAS alone, a simpler model that targets one of the most frequently altered pathways in cancer. These screens identified hits that are shared by both models as well as those unique to each one, emphasizing the importance of capturing the genetic complexity of human tumor genome landscapes in experimental models. Our follow-up analysis of two hits from the KRAS only screen suggest that classical genetic modifier screens in heterozygous mutant backgrounds that result in a modest, non-lethal reduction in candidate gene activity in the context of a whole animal --a key goal of systemic drug treatment-- may be a particularly useful approach to identify most rate limiting genetic vulnerabilities in disease models as ideal candidate drug targets.

genetics↗