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Updated: Mar 25, 2026
Isolating Intestinal Stem Cells from Adult Drosophila Midguts by FACS to Study Stem Cell Behavior During Aging
Published on: December 16, 2014
Stem-cell-specific endocytic degradation defects lead to intestinal dysplasia in Drosophila
Péter Nagy1, Laura Kovács1, Gyöngyvér O Sándor1
1Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Pázmány s. 1/C, Budapest H-1117, Hungary.
Abstract:
UV radiation resistance-associated gene (UVRAG) is a tumor suppressor involved in autophagy, endocytosis and DNA damage repair, but how its loss contributes to colorectal cancer is poorly understood. Here, we show that UVRAG deficiency in Drosophila intestinal stem cells leads to uncontrolled proliferation and impaired differentiation without preventing autophagy. As a result, affected animals suffer from gut dysfunction and short lifespan. Dysplasia upon loss of UVRAG is characterized by the accumulation of endocytosed ligands and sustained activation of STAT and JNK signaling, and attenuation of these pathways suppresses stem cell hyperproliferation. Importantly, the inhibition of early (dynamin-dependent) or late (Rab7-dependent) steps of endocytosis in intestinal stem cells also induces hyperproliferation and dysplasia. Our data raise the possibility that endocytic, but not autophagic, defects contribute to UVRAG-deficient colorectal cancer development in humans.
Insights
Loss of UV radiation resistance-associated gene (UVRAG) in fruit fly stem cells caused uncontrolled proliferation and gut dysfunction. Endocytic defects, not impaired autophagy, appear to drive colorectal cancer development in UVRAG deficiency.
Area of Science:
- Molecular Biology
- Genetics
- Cancer Research
Background:
- UV radiation resistance-associated gene (UVRAG) is a known tumor suppressor.
- UVRAG's roles in autophagy, endocytosis, and DNA repair are established.
- Its specific contribution to colorectal cancer development remains unclear.
Purpose of the Study:
- To investigate the role of UVRAG deficiency in colorectal cancer development.
- To elucidate the cellular mechanisms underlying UVRAG loss-induced dysplasia.
- To determine whether endocytic or autophagic defects are primarily responsible.
Main Methods:
- Utilized Drosophila melanogaster as a model organism.
- Examined the effects of UVRAG deficiency in Drosophila intestinal stem cells.
- Analyzed STAT and JNK signaling pathways and endocytosis inhibition.
Main Results:
- UVRAG deficiency in Drosophila intestinal stem cells led to uncontrolled proliferation and impaired differentiation.
- Dysplasia was characterized by accumulated endocytosed ligands and sustained STAT/JNK signaling.
- Inhibition of endocytosis, at both early and late stages, mimicked UVRAG loss phenotypes.
Conclusions:
- Endocytic defects, rather than impaired autophagy, are likely drivers of colorectal cancer in UVRAG-deficient settings.
- Sustained STAT and JNK signaling pathways contribute to stem cell hyperproliferation.
- These findings suggest potential therapeutic targets for UVRAG-deficient colorectal cancers.
