Project description:CARM1 inhibits ferroptosis through promoting the transcription of GPX4. HepG2 cells expressing control shRNAs or CARM1 shRNAs were treated with Sorafenib for 24 hours, and then the mRNAs were extracted and subjected to RNA-seq.
Project description:To find epigenetic factors potentially involved in Sorafenib resistance in hepatocellular carcinoma cells, an epigenetic factors-targeted CRISPR/Cas9 library was applied to perform the screening.
Project description:A CRISPR/Cas9 library screening identified CARM1 as a critical inhibitor for Sorafenib-induced ferroptosis in hepatocellular carcinoma cells
Project description:A CRISPR/Cas9 library screening identified CARM1 as a critical inhibitor for Sorafenib-induced ferroptosis in hepatocellular carcinoma cells [CRISPR screen]
Project description:BackgroundThe development of lethal cancer metastasis depends on the dynamic interactions between cancer cells and the tumor microenvironment, both of which are embedded in the extracellular matrix (ECM). The acquisition of resistance to detachment-induced apoptosis, also known as anoikis, is a critical step in the metastatic cascade. Thus, a more in-depth and systematic analysis is needed to identify the key drivers of anoikis resistance.MethodsGenome-wide CRISPR/Cas9 knockout screen was used to identify critical drivers of anoikis resistance using SKOV3 cell line and found protein-L-isoaspartate (D-aspartate) O-methyltransferase (PCMT1) as a candidate. Quantitative real-time PCR (qRT-PCR) and immune-histochemistry (IHC) were used to measure differentially expressed PCMT1 in primary tissues and metastatic cancer tissues. PCMT1 knockdown/knockout and overexpression were performed to investigate the functional role of PCMT1 in vitro and in vivo. The expression and regulation of PCMT1 and integrin-FAK-Src pathway were evaluated using immunoprecipitation followed by mass spectrometry (IP-MS), western blot analysis and live cell imaging.ResultsWe found that PCMT1 enhanced cell migration, adhesion, and spheroid formation in vitro. Interestingly, PCMT1 was released from ovarian cancer cells, and interacted with the ECM protein LAMB3, which binds to integrin and activates FAK-Src signaling to promote cancer progression. Strikingly, treatment with an antibody against extracellular PCMT1 effectively reduced ovarian cancer cell invasion and adhesion. Our in vivo results indicated that overexpression of PCMT1 led to increased ascites formation and distant metastasis, whereas knockout of PCMT1 had the opposite effect. Importantly, PCMT1 was highly expressed in late-stage metastatic tumors compared to early-stage primary tumors.ConclusionsThrough systematically identifying the drivers of anoikis resistance, we uncovered the contribution of PCMT1 to focal adhesion (FA) dynamics as well as cancer metastasis. Our study suggested that PCMT1 has the potential to be a therapeutic target in metastatic ovarian cancer.
Project description:In acute lymphoblastic leukemia (ALL), chromosomal translocations involving the KMT2A gene represent highly unfavorable prognostic factors and most commonly occur in patients less than 1 year of age. Rearrangements of the KMT2A gene drive epigenetic changes that lead to aberrant gene expression profiles that strongly favor leukemia development. Apart from this genetic lesion, the mutational landscape of KMT2A-rearranged ALL is remarkably silent, providing limited insights for the development of targeted therapy. Consequently, identifying potential therapeutic targets often relies on differential gene expression, yet the inhibition of these genes has rarely translated into successful therapeutic strategies. Therefore, we performed CRISPR-Cas9 knock-out screens to search for genetic dependencies in KMT2A-rearranged ALL. We utilized small-guide RNA libraries directed against the entire human epigenome and kinome in various KMT2A-rearranged ALL, as well as wild-type KMT2A ALL cell line models. This screening approach led to the discovery of the epigenetic regulators ARID4B and MBD3, as well as the receptor kinase BMPR2 as novel molecular vulnerabilities and attractive therapeutic targets in KMT2A-rearranged ALL.
Project description:Background: Lenvatinib is in a first-line therapy for advanced hepatocellular carcinoma (HCC). However, drug resistance is one of the principal obstacles for treatment failure. The molecular mechanism of Lenvatinib resistance has not been well investigated. Materials and methods: A genome-wide CRISPR/Cas9 knockout screening system was established and bioinformatic analysis was used to identify critical genes associated with Lenvatinib resistance. Cell proliferation assays, colony formation assays and cell migration assays were performed to investigate the effect of drug resistance associated genes, particularly DUSP4, on cancer cell malignant behavior during Lenvatinib treatment. In vivo experiments were conducted by using a xenograft mouse model. Results: We identified six genes that were associated with Lenvatinib resistance in HCC, including DUSP4, CCBL1, DHDH, CNTN2, NOS3 and TNF. DUSP4 was found to be significantly decreased at the mRNA and protein levels in Lenvatinib resistant HCC cells. DUSP4 knockout enhanced HCC cell survival, cell proliferation and migration during Lenvatinib treatment in vitro and in vivo, accompanied by regulation of p-ERK and p-MEK levels. This finding implied that DUSP4 deficiency induced Lenvatinib resistance. Interestingly, DUSP4 deficiency induced Lenvatinib resistance was abrogated by the MEK inhibitor Selumetinib, implying that MEK phosphorylation and DUSP4-inhibition dependent ERK activation were required for drug resistance. Finally, we found that DUSP4 deficiency was associated with HCC prognosis and response to Lenvatinib based on clinical data. Conclusions: DUSP4 deficiency mediates Lenvatinib resistance by activating MAPK/ERK signaling and combination therapy using Lenvatinib and MEK inhibitors may be a promising therapeutic strategy for overcoming Lenvatinib resistance.
Project description:Sorafenib is the standard treatment for advanced hepatocellular carcinoma (HCC). However, the development of drug resistance is common. By using genome-wide CRISPR/Cas9 library screening, we identify phosphoglycerate dehydrogenase (PHGDH), the first committed enzyme in the serine synthesis pathway (SSP), as a critical driver for Sorafenib resistance. Sorafenib treatment activates SSP by inducing PHGDH expression. With RNAi knockdown and CRISPR/Cas9 knockout models, we show that inactivation of PHGDH paralyzes the SSP and reduce the production of αKG, serine, and NADPH. Concomitantly, inactivation of PHGDH elevates ROS level and induces HCC apoptosis upon Sorafenib treatment. More strikingly, treatment of PHGDH inhibitor NCT-503 works synergistically with Sorafenib to abolish HCC growth in vivo. Similar findings are also obtained in other FDA-approved tyrosine kinase inhibitors (TKIs), including Regorafenib or Lenvatinib. In summary, our results demonstrate that targeting PHGDH is an effective approach to overcome TKI drug resistance in HCC.
Project description:Innate immunity is a non-specific host immune response against pathogen invasion. It exists widely in most of cells and is considered as the first line of defense against pathogen infection. Upon virus infection, the natural immune system is activated to generate immune response, thereby exerting the antiviral effect and effectively inhibiting the spread of virus in the body. With recent decades of research, people have found and identified the key regulatory factors of the natural immune response and the signal transduction. However the regulatory mechanisms of the factors are still unclear and need to be further explored. Our work used the CRISPR/Cas9 library to perform large-scale genome-wide, unbiased screening in immune cells, and discovered some novel genes involved in the regulation of type I IFN responses.