Browsing by Author "Wang, Jin"

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    Heterozygous deletion of chromosome 17p renders prostate cancer vulnerable to inhibition of RNA polymerase II
    (Springer Nature, 2018-10-22) Li, Yujing; Liu, Yunhua; Xu, Hanchen; Jiang, Guanglong; Van der Jeught, Kevin; Fang, Yuanzhang; Zhou, Zhuolong; Zhang, Lu; Frieden, Michael; Wang, Lifei; Luo, Zhenhua; Radovich, Milan; Schneider, Bryan P.; Deng, Yibin; Liu, Yunlong; Huang, Kun; He, Bin; Wang, Jin; He, Xiaoming; Zhang, Xinna; Ji, Guang; Lu, Xiongbin; Medical and Molecular Genetics, School of Medicine
    Heterozygous deletion of chromosome 17p (17p) is one of the most frequent genomic events in human cancers. Beyond the tumor suppressor TP53, the POLR2A gene encoding the catalytic subunit of RNA polymerase II (RNAP2) is also included in a ~20-megabase deletion region of 17p in 63% of metastatic castration-resistant prostate cancer (CRPC). Using a focused CRISPR-Cas9 screen, we discovered that heterozygous loss of 17p confers a selective dependence of CRPC cells on the ubiquitin E3 ligase Ring-Box 1 (RBX1). RBX1 activates POLR2A by the K63-linked ubiquitination and thus elevates the RNAP2-mediated mRNA synthesis. Combined inhibition of RNAP2 and RBX1 profoundly suppress the growth of CRPC in a synergistic manner, which potentiates the therapeutic effectivity of the RNAP2 inhibitor, α-amanitin-based antibody drug conjugate (ADC). Given the limited therapeutic options for CRPC, our findings identify RBX1 as a potentially therapeutic target for treating human CRPC harboring heterozygous deletion of 17p.
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    MAL2 drives immune evasion in breast cancer by suppressing tumor antigen presentation
    (The American Society for Clinical Investigation, 2021-01-07) Fang, Yuanzhang; Wang, Lifei; Wan, Changlin; Sun, Yifan; Van der Jeught, Kevin; Zhou, Zhuolong; Dong, Tianhan; So, Ka Man; Yu, Tao; Li, Yujing; Eyvani, Haniyeh; Colter, Austyn B.; Dong, Edward; Cao, Sha; Wang, Jin; Schneider, Bryan P.; Sandusky, George E.; Liu, Yunlong; Zhang, Chi; Lu, Xiongbin; Zhang, Xinna; Medical and Molecular Genetics, School of Medicine
    Immune evasion is a pivotal event in tumor progression. To eliminate human cancer cells, current immune checkpoint therapy is set to boost CD8+ T cell-mediated cytotoxicity. However, this action is eventually dependent on the efficient recognition of tumor-specific antigens via T cell receptors. One primary mechanism by which tumor cells evade immune surveillance is to downregulate their antigen presentation. Little progress has been made toward harnessing potential therapeutic targets for enhancing antigen presentation on the tumor cell. Here, we identified MAL2 as a key player that determines the turnover of the antigen-loaded MHC-I complex and reduces the antigen presentation on tumor cells. MAL2 promotes the endocytosis of tumor antigens via direct interaction with the MHC-I complex and endosome-associated RAB proteins. In preclinical models, depletion of MAL2 in breast tumor cells profoundly enhanced the cytotoxicity of tumor-infiltrating CD8+ T cells and suppressed breast tumor growth, suggesting that MAL2 is a potential therapeutic target for breast cancer immunotherapy.