Project description:Rhabdomyosarcoma (RMS) is a pediatric soft tissue sarcoma that causes significant devastation, with no effective therapy for relapsed disease. The mechanisms behind treatment failures are poorly understood. Our study showed that treatment of RMS cells with vincristine led to an increase in CD133-positive stem-like resistant cells. Single cell RNAseq analysis revealed that MYC and YBX1 were among the top-scoring transcription factors in CD133-high expressing cells. Targeting MYC and YBX1 using CRISPR/Cas9 reduced stem-like characteristics and viability of the vincristine-resistant cells. MYC and YBX1 showed mutual regulation, with MYC binding to the YBX1 promoter and YBX1 binding to MYC mRNA. The MYC inhibitor MYC361i synergized with vincristine to reduce tumor growth and stem-like cells in a zebrafish model of RMS. MYC and YBX expression showed a positive correlation in RMS patients, and high MYC expression correlated with poor survival. Targeting the MYC-YBX1 axis holds promise for improving survival in RMS patients.
Project description:we show that YBX1 is specifically required for maintaining myeloid leukemia cell survival but is dispensable for normal hematopoiesis. We found that expression of YBX1 is significantly upregulated in myeloid leukemia cells, and deletion of YBX1 significantly induces apoptosis, coupled with reduced proliferation and impaired leukemic capacity of primary human and mouse acute myeloid leukemia (AML) cells in vitro and in vivo. Loss of YBX1 does not obviously affect normal hematopoiesis. Mechanistically, YBX1 interacts with IGF2BPs and stabilizes m6A-tagged RNA. Moreover, YBX1 deficiency promotes mRNA decay in an m6A-dependent manner, which contributes to the defective survival due to YBX1 deletion. Thus, our findings uncover a selective and critical role of YBX1 in maintaining myeloid leukemia survival that might provide a rationale for the therapeutic targeting of YBX1 in myeloid leukemia.
Project description:we show that YBX1 is specifically required for maintaining myeloid leukemia cell survival but is dispensable for normal hematopoiesis. We found that expression of YBX1 is significantly upregulated in myeloid leukemia cells, and deletion of YBX1 significantly induces apoptosis, coupled with reduced proliferation and impaired leukemic capacity of primary human and mouse acute myeloid leukemia (AML) cells in vitro and in vivo. Loss of YBX1 does not obviously affect normal hematopoiesis. Mechanistically, YBX1 interacts with IGF2BPs and stabilizes m6A-tagged RNA. Moreover, YBX1 deficiency promotes mRNA decay in an m6A-dependent manner, which contributes to the defective survival due to YBX1 deletion. Thus, our findings uncover a selective and critical role of YBX1 in maintaining myeloid leukemia survival that might provide a rationale for the therapeutic targeting of YBX1 in myeloid leukemia.
Project description:we show that YBX1 is specifically required for maintaining myeloid leukemia cell survival but is dispensable for normal hematopoiesis. We found that expression of YBX1 is significantly upregulated in myeloid leukemia cells, and deletion of YBX1 significantly induces apoptosis, coupled with reduced proliferation and impaired leukemic capacity of primary human and mouse acute myeloid leukemia (AML) cells in vitro and in vivo. Loss of YBX1 does not obviously affect normal hematopoiesis. Mechanistically, YBX1 interacts with IGF2BPs and stabilizes m6A-tagged RNA. Moreover, YBX1 deficiency promotes mRNA decay of MYC and BCL2 in an m6A-dependent manner, which contributes to the defective survival due to YBX1 deletion. Thus, our findings uncover a selective and critical role of YBX1 in maintaining myeloid leukemia survival that might provide a rationale for the therapeutic targeting of YBX1 in myeloid leukemia.
Project description:Rhabdomyosarcoma (RMS) is a highly metastatic soft-tissue sarcoma that often develops resistance to current therapies, including vincristine. Since the existing treatments have not significantly improved survival, there is a critical need for new therapeutic approaches for RMS patients. FOXM1, a known oncogene, is highly expressed in RMS, and is associated with the worst prognosis in RMS patients. In the present study, we found that the combination treatment with specific FOXM1 inhibitor RCM1 and low doses of vincristine is more effective in increasing apoptosis and decreasing RMS cell proliferation in vitro compared to single drugs alone. Since RCM1 is highly hydrophobic, we developed innovative nanoparticle delivery system containing poly-beta-amino-esters and folic acid (NPFA), which efficiently delivers RCM1 to mouse RMS tumors in vivo. The combination of low doses of vincristine together with intravenous administration of NPFA nanoparticles containing RCM1 effectively reduced RMS tumor volumes, increased tumor cell death and decreased tumor cell proliferation in RMS tumors compared to RCM1 or vincristine alone. The combination therapy was non-toxic as demonstrated by liver metabolic panels using peripheral blood serum. Using RNA-seq of dissected RMS tumors, we identified Chac1 as a uniquely downregulated gene after the combination treatment. Knockdown of Chac1 in RMS cells in vitro recapitulated the effects of the combination therapy. Altogether, combination treatment with low doses of vincristine and nanoparticle delivery of FOXM1 inhibitor RCM1 in a pre-clinical model of RMS has superior anti-tumor effects and decreases CHAC1 while reducing vincristine toxicity
Project description:In order to identify YBX1 binding sites on endogenous RNA, we performed HITS-CLIP on endogenous YBX1 We used a previously published method to perform HITS-CLIP on endogenous YBX1 (Licatalosi D, et al. 2008, Nature 456:464-U22)
Project description:In order to identify YBX1 binding sites on tRNA fragments, we performed small-RNA HITS-CLIP on endogenous YBX1 We used a previously published method to perform HITS-CLIP on endogenous YBX1 (Chi SW, et al. 2009, Nature 460:479)
Project description:YBX1 is a multifunctional protein involved in the control of transcription and translation. We identified YBX1 as an target of MEK/ERK signaling in colorectal cancer cell lines. We performed a ChIP-chip analysis of HCT116 cells to identify new potential target genes of YBX1. Comparison of input DNA fragments with fragments coprecipitated with YBX1 in HCT116 cells.
Project description:In order to identify YBX1-dependent targets that are modulated under hypoxic conditions, we used control and YBX1 knockdown cells grown under normoxia and hypoxia to profile gene expression levels. Control and YBX1-knockdown cells were grown and profiled under hypoxia and normoxia to identify YBX1-dependent hypoxia-induced target transcripts.
Project description:In order to identify YBX1-dependent targets that are modulated upon changing the levels of endogenous tRFs, we used transient transfection of antisense locked-nucleic acids (LNAs) against tRFAsp, tRFGly, tRFGlu, and tRFTyr followed by microarray profiling. Synthetic antisense locked-nucleic acids (LNAs) targeting the YBX1 binding site on tRFAsp, tRFGly, tRFGlu, and tRFTyr were transfected into control and YBX1-knockdown cells to identify YBX1-dependent targets that are modulated due to tRF loss-of-function.