Browsing by Author "Katon, Jesse M"

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    An aberrant SREBP-dependent lipogenic program promotes metastatic prostate cancer.
    (Nature genetics, 2018-02) Chen, Ming; Zhang, Jiangwen; Sampieri, Katia; Clohessy, John G; Mendez, Lourdes; Gonzalez-Billalabeitia, Enrique; Liu, Xue-Song; Lee, Yu-Ru; Fung, Jacqueline; Katon, Jesse M; Menon, Archita Venugopal; Webster, Kaitlyn A; Ng, Christopher; Palumbieri, Maria Dilia; Diolombi, Moussa S; Breitkopf, Susanne B; Teruya-Feldstein, Julie; Signoretti, Sabina; Bronson, Roderick T; Asara, John M; Castillo-Martin, Mireia; Cordon-Cardo, Carlos; Pandolfi, Pier Paolo
    Lipids, either endogenously synthesized or exogenous, have been linked to human cancer. Here we found that PML is frequently co-deleted with PTEN in metastatic human prostate cancer (CaP). We demonstrated that conditional inactivation of Pml in the mouse prostate morphs indolent Pten-null tumors into lethal metastatic disease. We identified MAPK reactivation, subsequent hyperactivation of an aberrant SREBP prometastatic lipogenic program, and a distinctive lipidomic profile as key characteristic features of metastatic Pml and Pten double-null CaP. Furthermore, targeting SREBP in vivo by fatostatin blocked both tumor growth and distant metastasis. Importantly, a high-fat diet (HFD) induced lipid accumulation in prostate tumors and was sufficient to drive metastasis in a nonmetastatic Pten-null mouse model of CaP, and an SREBP signature was highly enriched in metastatic human CaP. Thus, our findings uncover a prometastatic lipogenic program and lend direct genetic and experimental support to the notion that a Western HFD can promote metastasis.
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    The APC/C E3 Ligase Complex Activator FZR1 Restricts BRAF Oncogenic Function.
    (Cancer discovery, 2017-04) Wan, Lixin; Chen, Ming; Cao, Juxiang; Dai, Xiangpeng; Yin, Qing; Zhang, Jinfang; Song, Su-Jung; Lu, Ying; Liu, Jing; Inuzuka, Hiroyuki; Katon, Jesse M; Berry, Kelsey; Fung, Jacqueline; Ng, Christopher; Liu, Pengda; Song, Min Sup; Xue, Lian; Bronson, Roderick T; Kirschner, Marc W; Cui, Rutao; Pandolfi, Pier Paolo; Wei, Wenyi
    BRAF drives tumorigenesis by coordinating the activation of the RAS/RAF/MEK/ERK oncogenic signaling cascade. However, upstream pathways governing BRAF kinase activity and protein stability remain undefined. Here, we report that in primary cells with active APCFZR1, APCFZR1 earmarks BRAF for ubiquitination-mediated proteolysis, whereas in cancer cells with APC-free FZR1, FZR1 suppresses BRAF through disrupting BRAF dimerization. Moreover, we identified FZR1 as a direct target of ERK and CYCLIN D1/CDK4 kinases. Phosphorylation of FZR1 inhibits APCFZR1, leading to elevation of a cohort of oncogenic APCFZR1 substrates to facilitate melanomagenesis. Importantly, CDK4 and/or BRAF/MEK inhibitors restore APCFZR1 E3 ligase activity, which might be critical for their clinical effects. Furthermore, FZR1 depletion cooperates with AKT hyperactivation to transform primary melanocytes, whereas genetic ablation of Fzr1 synergizes with Pten loss, leading to aberrant coactivation of BRAF/ERK and AKT signaling in mice. Our findings therefore reveal a reciprocal suppression mechanism between FZR1 and BRAF in controlling tumorigenesis.Significance: FZR1 inhibits BRAF oncogenic functions via both APC-dependent proteolysis and APC-independent disruption of BRAF dimers, whereas hyperactivated ERK and CDK4 reciprocally suppress APCFZR1 E3 ligase activity. Aberrancies in this newly defined signaling network might account for BRAF hyperactivation in human cancers, suggesting that targeting CYCLIN D1/CDK4, alone or in combination with BRAF/MEK inhibition, can be an effective anti-melanoma therapy. Cancer Discov; 7(4); 424-41. ©2017 AACR.See related commentary by Zhang and Bollag, p. 356This article is highlighted in the In This Issue feature, p. 339.