DPPA3-HIF1a axis controls colorectal cancer chemoresistance by imposing a slow cell-cycle phenotype (DNA methylation arrays)
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ABSTRACT: Tumor relapse is linked to rapid chemoresistance and represents a bottleneck for cancer therapy success. Engagement of a reduced proliferation state is a non-mutational mechanism exploited by cancer cells to bypass therapy-induced cell death. Through combining pulse-chase experiments in engineered CRC cells and transcriptomic analyses, we identified DPPA3 as a master regulator of slow-cycling phenotype in CRC. We find that DPPA3 stabilizes HIF1a even in normoxia thus limiting nuclear CCNB1 levels and represses DNA replication and cell cycle programs resulting in a slow cell-cycle phenotype. Down-regulation of HIF1a partially restores a chemosensitive proliferative phenotype in DPPA3-overexpressing cancer cells. In cohorts of patient samples, we find that DPPA3 is a predictive biomarker of CRC chemotherapeutic resistance and tumor relapse. Our work demonstrates that slow-cycling cancer cells exploit a DPPA3/HIF1a axis to support tumor persistence under therapeutic stress and provides key insights on the molecular regulation of tumor cell slow-cycliness and chemoresistance. This dataset comprises DNA methylation data of SW1222 CRC cells subjected to DPPA3 overexpression for 5 days.
Project description:Comparative transcriptome of SW1222 colorectal cancer (CRC) cells that overexpress or are depleted of DPPA3 to identify genes involved in regulating of the slow-cycling cancer cell properties to uncover the molecular mechanism of the non-mutational chemoresistant phenotype.
Project description:Genome-wide DNA demethylation is a unique feature of mammalian development and naïve pluripotent stem cells. So far, it was unclear how mammals specifically achieve global DNA hypomethylation, given the high conservation of the DNA (de-)methylation machinery among vertebrates. We found that DNA demethylation requires TET activity but mostly occurs at sites where TET proteins are not bound suggesting a rather indirect mechanism. Among the few specific genes bound and activated by TET proteins was the naïve pluripotency and germline marker Dppa3 (Pgc7, Stella), which undergoes TDG dependent demethylation. The requirement of TET proteins for genome-wide DNA demethylation could be bypassed by ectopic expression of Dppa3. We show that DPPA3 binds and displaces UHRF1 from chromatin and thereby prevents the recruitment and activation of the maintenance DNA methyltransferase DNMT1. We demonstrate that DPPA3 alone can drive global DNA demethylation when transferred to amphibians (Xenopus) and fish (medaka), both species that naturally do not have a Dppa3 gene and exhibit no post-fertilization DNA demethylation. Our results show that TET proteins are responsible for active and - indirectly also for - passive DNA demethylation; while TET proteins initiate local and gene-specific demethylation in vertebrates, the recent emergence of DPPA3 introduced a unique means of genome-wide passive demethylation in mammals and contributed to the evolution of epigenetic regulation during early mammalian development.
Project description:Colorectal cancer is a common cancer and causes high mortality worldwide. It is urgent to explore its pathogenesis and seek effective therapeutic strategies. Here, the author showed that EEF1D expression in colorectal cancer cells is required to promote tumor growth and metastasis. Moreover, we further performed the proteomic analysis to gain a deeper mechanistic understanding of EEF1D in CRC. We found that EEF1D interacted with various cancer-related proteins. These interactions further support the importance of EEF1D in colorectal cancer.
Project description:DPPA3 mutants were overexpressed using a doxycycline system to identify regions in DPPA3 necessary for DNA methylation maintenance suppression
Project description:Prostate cancer (PCa) is a leading cause of cancer-related deaths. The slow evolution of prostatic precancerous lesions to malignant tumors provides a broad time-frame for strategies targeting disease emergence. To characterize prostatic intraepithelial neoplasia (PIN) progression, we conducted longitudinal studies on prostates of genetically-engineered Pten(i)pe- /- mice. We discovered that early PINs are hypoxic and that hypoxia-inducible factor 1 alpha (HIF1A) signaling is activated in luminal cells during disease progression. Luminal HIF1A enhances glucose metabolism and promotes a PIN-derived secretome that increases the recruitment of myeloid-derived suppressor cells, thus dampening immune surveillance. Moreover, pharmacological inhibition of HIF1A induces apoptosis in early PIN lesions, and slows the proliferation of late ones. Therefore, our study identifies HIF1A as a target for PCa prevention. Importantly, we also demonstrate that HIF1A signaling correlates with the emergence of prostatic luminal cells expressing TGM2, the expression of which predicts early relapse after primary intervention in PCa patients.
Project description:Tet1, Tet2 and Tet1/Tet2 catalytic mutants as well as DPPA3 KO ESCs harboring a doxycyclin inducible Dppa3 transgene were induced for several days to monitor LINE-1 methylation levels.
Project description:Prostate cancer (PCa) is a leading cause of cancer-related deaths. The slow evolution of precancerous lesions to malignant tumors provides a broad time-frame for preventing PCa. To characterize prostatic intraepithelial neoplasia (PIN) progression, we conducted longitudinal studies on Pten(i)pe-/- mice which recapitulate prostate carcinogenesis in humans. We discovered that early PINs are hypoxic and that hypoxia-inducible factor 1 alpha (HIF1A) signaling is activated in luminal cells, which enhances malignant progression. Luminal HIF1A dampens immune surveillance and drives luminal plasticity leading to the emergence of cells with selective Transglutaminase 2 (TGM2) expression and impaired androgen signaling. Importantly, elevated TGM2 levels in PCa patients are associated with shortened progression-free survival after prostatectomy. Finally, we show that pharmacologically inhibiting HIF1A impairs cell proliferation and induces apoptosis in PINs. Therefore, our study demonstrates that HIF1A is a target for PCa prevention, and that TGM2 is a promising prognostic biomarker of early relapse after prostatectomy.
Project description:Here we performed a ChIP-seq experiment on a sample of adherent cultures of mouse neural stem cells (NS5 cell line) expressing an inducible HA-tagged version of the proneural factor MyT1 (MyT1-HA, under TetON control) after activation by doxycycline hyclate (DOX). This resulted in the generation of a genome-wide map of MyT1-HA binding to chromatin.
Project description:Colorectal cancer (CRC) is characterized by extensive intra-tumor heterogeneity. The cancer stem cell (CSC) theory may explain the mechanisms underlying the non-genetic heterogeneity and their characteristics of prominent plasticity are emerging to be elucidated. By tracking the spheroid formation and growth capacity of CRC CSCs with a single-cell resolution using an organoid culture, we revealed CSCs consisted of subpopulations with a dual (fast and slow)-growing pattern. When isolated, the slow-growing CSCs remained slow-growing and converted into dual-growing CSCs under certain conditions. The slow-growing cells showed low levels of MAP kinase activity and were resistant to a MEK1/2 inhibitor as well as chemo-drugs. The MSI1 gene was down-regulated in the slow-growing CSCs and played a key role in the transition between slow- and dual-growing CSCs. Isolation of slow-growing CSCs will provide a platform to elucidate the role of the plasticity of CSCs in drug resistance and tumor recurrence. To disclose the molecular characteristics of the CSC subclones with the distinct growth features, we analyzed the differentially expressed genes between the subgroups.