Project description:Despite the clinical benefit of androgen-deprivation therapy (ADT), the majority of patients with advanced prostate cancer (PCa) ultimately develop lethal castration-resistant prostate cancer (CRPC). In this study, we identified thioesterase superfamily member 6 (THEM6) as a marker of ADT resistance in PCa. In patients, THEM6 expression correlates with progressive disease and is associated with poor survival. THEM6 deletion reduces in vivo tumour growth and restores castration sensitivity in orthograft models of CRPC. Mechanistically, THEM6 is located at the endoplasmic reticulum (ER) membrane and controls lipid homeostasis by regulating intracellular levels of ether lipids. As a consequence, THEM6 loss in CRPC cells significantly alters ER function, preventing lipid-mediated induction of ATF4 and reducing de novo sterol biosynthesis. Finally, we show that THEM6 is required for the establishment of the MYC-induced stress response. Thus, similar to PCa, THEM6 loss significantly impairs tumorigenesis in the MYC-dependent subtype of triple negative breast cancer. Altogether our results highlight THEM6 as a novel component of the treatment-induced stress response and a promising target for the treatment of CRPC and MYC-driven cancer.
Project description:Despite the clinical benefit of androgen-deprivation therapy (ADT), the majority of patients with advanced prostate cancer (PCa) ultimately develop lethal castration-resistant prostate cancer (CRPC). In this study, we identified thioesterase superfamily member 6 (THEM6) as a marker of ADT resistance in PCa. In patients, THEM6 expression correlates with progressive disease and is associated with poor survival. THEM6 deletion reduces in vivo tumour growth and restores castration sensitivity in orthograft models of CRPC. Mechanistically, THEM6 is located at the endoplasmic reticulum (ER) membrane and controls lipid homeostasis by regulating intracellular levels of ether lipids. As a consequence, THEM6 loss in CRPC cells significantly alters ER function, preventing lipid-mediated induction of ATF4 and reducing de novo sterol biosynthesis. Finally, we show that THEM6 is required for the establishment of the MYC-induced stress response. Thus, similar to PCa, THEM6 loss significantly impairs tumorigenesis in the MYC-dependent subtype of triple negative breast cancer. Altogether our results highlight THEM6 as a novel component of the treatment-induced stress response and a promising target for the treatment of CRPC and MYC-driven cancer.
Project description:Despite the clinical benefit of androgen-deprivation therapy (ADT), the majority of patients with advanced prostate cancer (PCa) ultimately develop lethal castration-resistant prostate cancer (CRPC). In this study, we identified thioesterase superfamily member 6 (THEM6) as a marker of ADT resistance in PCa. In patients, THEM6 expression correlates with progressive disease and is associated with poor survival. THEM6 deletion reduces in vivo tumour growth and restores castration sensitivity in orthograft models of CRPC. Mechanistically, THEM6 is located at the endoplasmic reticulum (ER) membrane and controls lipid homeostasis by regulating intracellular levels of ether lipids. As a consequence, THEM6 loss in CRPC cells significantly alters ER function, preventing lipid-mediated induction of ATF4 and reducing de novo sterol biosynthesis. Finally, we show that THEM6 is required for the establishment of the MYC-induced stress response. Thus, similar to PCa, THEM6 loss significantly impairs tumorigenesis in the MYC-dependent subtype of triple negative breast cancer. Altogether our results highlight THEM6 as a novel component of the treatment-induced stress response and a promising target for the treatment of CRPC and MYC-driven cancer.
Project description:Despite the clinical benefit of androgen-deprivation therapy (ADT), the majority of patients with advanced prostate cancer (PCa) ultimately develop lethal castration-resistant prostate cancer (CRPC). In this study, we identified thioesterase superfamily member 6 (THEM6) as a marker of ADT resistance in PCa. THEM6 deletion reduces in vivo tumour growth and restores castration sensitivity in orthograft models of CRPC. Mechanistically, we show that the ER membrane-associated protein THEM6 regulates intracellular levels of ether lipids and is essential to trigger the induction of the ER stress response (UPR). Consequently, THEM6 loss in CRPC cells significantly alters ER function, reducing de novo sterol biosynthesis and preventing lipid-mediated activation of ATF4. Finally, we demonstrate that high THEM6 expression is associated with poor survival and correlates with high levels of UPR activation in PCa patients. Altogether, our results highlight THEM6 as a novel driver of therapy resistance in PCa as well as a promising target for the treatment of CRPC.
Project description:Despite the clinical benefit of androgen-deprivation therapy (ADT), the majority of patients with advanced prostate cancer (PCa) ultimately develop lethal castration-resistant prostate cancer (CRPC). In this study, we identified thioesterase superfamily member 6 (THEM6) as a marker of ADT resistance in PCa. THEM6 deletion reduces in vivo tumour growth and restores castration sensitivity in orthograft models of CRPC. Mechanistically, we show that the ER membrane-associated protein THEM6 regulates intracellular levels of ether lipids and is essential to trigger the induction of the ER stress response (UPR). Consequently, THEM6 loss in CRPC cells significantly alters ER function, reducing de novo sterol biosynthesis and preventing lipid-mediated activation of ATF4. Finally, we demonstrate that high THEM6 expression is associated with poor survival and correlates with high levels of UPR activation in PCa patients. Altogether, our results highlight THEM6 as a novel driver of therapy resistance in PCa as well as a promising target for the treatment of CRPC.
Project description:Photodynamic therapy (PDT) involves light activation of the photosensitizer to generate reactive molecular species that induce cell modulation or death. Based on earlier findings showing that the photosensitizer benzoporphyrin derivative (BPD) is a breast cancer resistance protein (ABCG2) substrate, we investigated the ability of the P-glycoprotein (P-gp) and multidrug resistance-associated protein 1 (MRP1) to transport BPD. In a panel of breast cancer cell lines overexpressing P-gp, MRP1, or ABCG2, BPD transport occurs only in cells overexpressing P-gp and ABCG2. Intracellular BPD fluorescence is not affected by MRP1, as determined by flow cytometry. To bypass P-gp- and ABCG2-mediated efflux of BPD, we introduce a lipidation strategy to create BPD derivatives that are no longer P-gp and ABCG2 substrates. The phospholipid-conjugated BPD and its nanoliposomal formulation evade both P-gp- and ABCG2-mediated transport. In cytotoxicity assays, lipidated BPD and its nanoliposomal formulation abrogate P-gp- and ABCG2-mediated PDT resistance. We verify that P-gp, like ABCG2, plays a role in BPD transport and BPD-PDT resistance. Furthermore, we introduce porphyrin-lipid nanovesicles as a new strategy to escape P-gp and ABCG2-mediated efflux of BPD for improved PDT outcomes in two breast cancer cell lines.
Project description:The goal of this study was to compare the transcriptome between wild type strain of Listeria monocytogenes and delete nmlR mutant strain of L. monocytogenes using NGS. Method: Duplicate samples of rRNA depleted RNA from wild type and mutants were used to study transcriptomes by ion torrent platform. Transcriptomes of wild type and nmlR mutant were compared by EDGE-pro program. Result: Differential expression by EDGE-pro showed 74 genes with differential expressions between wild type and nmlR null mutant (46 genes were negatively regluated and 28 genes were positively regulated by NmlR). rRNA-depleted RNA samples from stationary phase wilde type and nmlR null mutant cultures were used to compare transcriptomes. Some affected genes from RNAseq result were selected for confirmation by quantitative reverse transcriptase PCR.