SKP2 knockout in Rb1/p53 deficient transgenic mouse models of osteosarcoma induces macrophage infiltration and drives transcription of genes with favorable prognosis in patients
Ontology highlight
ABSTRACT: To study SKP2 in osteosarcoma, we generated a Skp2 KO line and a Skp2 intact line of transgenic OS mouse models: germline Skp2 knockout (“TKO”: Osx1-Cre;Rb1lox/lox;p53lox/lox;SKP2) versus Skp2 intact (“DKO”: Osx1-Cre;Rb1lox/lox;p53lox/lox). We then performed bulk RNAseq of the SKP2 KO vs SKP2 intact OS.
Project description:Osteosarcoma (OS) is the most common primary pediatric bone malignancy. One promising new therapeutic target is SKP2, encoding a substrate recognition factor of the SCF E3 ubiquitin ligase responsible for ubiquitination and proteasome degradation of substrate p27, thus driving cellular proliferation. We have shown previously that knockout of Skp2 in an immunocompetent transgenic mouse model of OS improved survival, drove apoptosis, and induced tumor inflammation. Here, we applied single-cell RNA-sequencing (scRNA-seq) to study primary OS tumors derived from Osx-Cre driven conditional knockout of Rb1 and Trp53. We showed that murine OS models recapitulate the tumor heterogeneity and microenvironment complexity observed in patient tumors. We further compared this model with OS models with functional disruption of Skp2: one with Skp2 knockout and the other with the Skp2-p27 interaction disrupted (resulting in p27 overexpression). We found reduction of T cell exhaustion and upregulation of interferon activation, along with evidence of replicative and endoplasmic reticulum-related stress in the Skp2 disruption models, and showed that interferon induction was correlated with improved survival in OS patients. Additionally, our scRNA-seq analysis uncovered decreased activities of metastasis-related gene signatures in the Skp2-modulated OS, which we validated by observation of a strong reduction in lung metastasis in the Skp2 knockout mice. Finally, we report several potential mechanisms of escape from targeting Skp2 in OS, including upregulation of Myc targets, DNA copy number amplification and overexpression of alternative E3 ligase genes, and potential alternative lineage activation. These mechanistic insights into OS tumor biology and Skp2 function suggest novel targets for new, synergistic therapies, while the data and our comprehensive analysis may serve as a public resource for further big data-driven OS research.
Project description:Purpose: To detect the global effects of Class1A PI3K TKO deletion on the HSC transcriptome. Method: Whole BM cells from donor mice TKO: Pik3calox-lox; Pik3cblox-lox; Pik3cd-/-;Mx1-Cre, δ KO: Pik3calox-lox; Pik3cblox-lox;Pik3cd-/- (littermate control) and WT: WT, Mx1-Cre (control) were transplanted into lethally irradiated 6-8 week old B6.SJL mice (N=7 per group). Recipient mice were injected 4 weeks post transplant interperitoneally with pIpC 250μg x2, 48 hours apart to ensure Pik3ca and Pik3cb excision. At 4 weeks post PIPC, BM cells were harvested from femurs, tibiae, ilia and vertebrae by gentle crushing. Donor-derived HSCs (Lin-cKit+Sca1+Flk2-CD48-CD150+) cell populations were sorted into RNA extraction buffer (ARCTURUS PicoPure). cDNA was amplified from total RNA using the Ovation® RNA‑Seq System V2. Sequencing was performed using the NGS platform llumina-HiSeq2500/4000.
Project description:Expression analysis from two genetically engineered mouse models of osteosarcoma determine the expression profile of mouse osteosarcoma Human osteosarcoma (OS) is comprised of three different subtypes: fibroblastic, chondroblastic and osteoblastic. We previously generated a mouse model of fibroblastic OS by conditional deletion of p53 and Rb in osteoblasts. Here we report an accurate mouse model of the osteoblastic subtype using shRNA-based suppression of p53. Like human OS, tumors frequently present in the long bones and preferentially disseminate to the lungs; features less consistently modeled using Cre:lox approaches. Our approach allowed direct comparison of the in vivo consequences of targeting the same genetic drivers using different technology. This demonstrated that the effects of Cre:lox and shRNA mediated knock-down are qualitatively different, at least in the context of osteosarcoma. Through the use of complementary genetic modification strategies we have established a model of a distinct clinical subtype of OS that was not previously represented and more fully recapitulated the clinical spectrum of this human tumor. 4 primary tumors from Cre:lox OS model; 4 primary tumors from shRNA OS model.
Project description:rs04-04_skp2_cul4 - comparison_col0vsskp2 - Antisense and mutants of the SKP2 and CUL4 genes are compared to the Wt in order to identify the genes controlled by those SCF proteins. - Comparison Col0 versus skp2
Project description:Expression analysis from two genetically engineered mouse models of osteosarcoma determine the expression profile of mouse osteosarcoma Human osteosarcoma (OS) is comprised of three different subtypes: fibroblastic, chondroblastic and osteoblastic. We previously generated a mouse model of fibroblastic OS by conditional deletion of p53 and Rb in osteoblasts. Here we report an accurate mouse model of the osteoblastic subtype using shRNA-based suppression of p53. Like human OS, tumors frequently present in the long bones and preferentially disseminate to the lungs; features less consistently modeled using Cre:lox approaches. Our approach allowed direct comparison of the in vivo consequences of targeting the same genetic drivers using different technology. This demonstrated that the effects of Cre:lox and shRNA mediated knock-down are qualitatively different, at least in the context of osteosarcoma. Through the use of complementary genetic modification strategies we have established a model of a distinct clinical subtype of OS that was not previously represented and more fully recapitulated the clinical spectrum of this human tumor.
Project description:rs04-04_skp2_cul4 - comparison_col0vsskp2 - Antisense and mutants of the SKP2 and CUL4 genes are compared to the Wt in order to identify the genes controlled by those SCF proteins. - Comparison Col0 versus skp2 2 dye-swap - wt vs mutant comparison
Project description:Transcriptional profiling of mouse HSC comparing wild type (WT) and Skp2 knockout Collected bone marrow (BM) cells from WT and Skp2 knockout mice, stained with HSC surface markers for FACS. Collected HSC and extracted total RNA then sent out for microarray analysis.