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Browsing by Author "Van der Jeught, Kevin"
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Item A T Cell‐Engaging Tumor Organoid Platform for Pancreatic Cancer Immunotherapy(Wiley, 2023) Zhou, Zhuolong; Van der Jeught, Kevin; Li, Yujing; Sharma, Samantha; Yu, Tao; Moulana, Ishara; Liu, Sheng; Wan, Jun; Territo, Paul R.; Opyrchal, Mateusz; Zhang, Xinna; Wan, Guohui; Lu, Xiongbin; Medical and Molecular Genetics, School of MedicinePancreatic ductal adenocarcinoma (PDA) is a clinically challenging disease with limited treatment options. Despite a small percentage of cases with defective mismatch DNA repair (dMMR), PDA is included in the most immune‐resistant cancer types that are poorly responsive to immune checkpoint blockade (ICB) therapy. To facilitate drug discovery combating this immunosuppressive tumor type, a high‐throughput drug screen platform is established with the newly developed T cell‐incorporated pancreatic tumor organoid model. Tumor‐specific T cells are included in the pancreatic tumor organoids by two‐step cell packaging, fully recapitulating immune infiltration in the immunosuppressive tumor microenvironment (TME). The organoids are generated with key components in the original tumor, including epithelial, vascular endothelial, fibroblast and macrophage cells, and then packaged with T cells into their outside layer mimicking a physical barrier and enabling T cell infiltration and cytotoxicity studies. In the PDA organoid‐based screen, epigenetic inhibitors ITF2357 and I‐BET151 are identified, which in combination with anti‐PD‐1 based therapy show considerably greater anti‐tumor effect. The combinatorial treatment turns the TME from immunosuppressive to immunoactive, up‐regulates the MHC‐I antigen processing and presentation, and enhances the effector T cell activity. The standardized PDA organoid model has shown great promise to accelerate drug discovery for the immunosuppressive cancer.Item Atractylenolide I enhances responsiveness to immune checkpoint blockade therapy by activating tumor antigen presentation(The American Society for Clinical Investigation, 2021-05-17) Xu, Hanchen; Van der Jeught, Kevin; Zhou, Zhuolong; Zhang, Lu; Yu, Tao; Sun, Yifan; Li, Yujing; Wan, Changlin; So, Ka Man; Liu, Degang; Frieden, Michael; Fang, Yuanzhang; Mosley, Amber L.; He, Xiaoming; Zhang, Xinna; Sandusky, George E.; Liu, Yunlong; Meroueh, Samy O.; Zhang, Chi; Wijeratne, Aruna B.; Huang, Cheng; Ji, Guang; Lu, Xiongbin; Medical and Molecular Genetics, School of MedicineOne of the primary mechanisms of tumor cell immune evasion is the loss of antigenicity, which arises due to lack of immunogenic tumor antigens as well as dysregulation of the antigen processing machinery. In a screen for small-molecule compounds from herbal medicine that potentiate T cell–mediated cytotoxicity, we identified atractylenolide I (ATT-I), which substantially promotes tumor antigen presentation of both human and mouse colorectal cancer (CRC) cells and thereby enhances the cytotoxic response of CD8+ T cells. Cellular thermal shift assay (CETSA) with multiplexed quantitative mass spectrometry identified the proteasome 26S subunit non–ATPase 4 (PSMD4), an essential component of the immunoproteasome complex, as a primary target protein of ATT-I. Binding of ATT-I with PSMD4 augments the antigen-processing activity of immunoproteasome, leading to enhanced MHC-I–mediated antigen presentation on cancer cells. In syngeneic mouse CRC models and human patient–derived CRC organoid models, ATT-I treatment promotes the cytotoxicity of CD8+ T cells and thus profoundly enhances the efficacy of immune checkpoint blockade therapy. Collectively, we show here that targeting the function of immunoproteasome with ATT-I promotes tumor antigen presentation and empowers T cell cytotoxicity, thus elevating the tumor response to immunotherapy.Item Drug resistance and new therapies in colorectal cancer(Baishideng, 2018-09-14) Van der Jeught, Kevin; Xu, Han-Chen; Li, Yu-Jing; Lu, Xiong-Bin; Ji, Guang; Medical and Molecular Genetics, School of MedicineColorectal cancer (CRC) is often diagnosed at an advanced stage when tumor cell dissemination has taken place. Chemo- and targeted therapies provide only a limited increase of overall survival for these patients. The major reason for clinical outcome finds its origin in therapy resistance. Escape mechanisms to both chemo- and targeted therapy remain the main culprits. Here, we evaluate major resistant mechanisms and elaborate on potential new therapies. Amongst promising therapies is α-amanitin antibody-drug conjugate targeting hemizygous p53 loss. It becomes clear that a dynamic interaction with the tumor microenvironment exists and that this dictates therapeutic outcome. In addition, CRC displays a limited response to checkpoint inhibitors, as only a minority of patients with microsatellite instable high tumors is susceptible. In this review, we highlight new developments with clinical potentials to augment responses to checkpoint inhibitors.Item 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 MedicineHeterozygous 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.Item 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 MedicineImmune 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.Item An organoid-based screen for epigenetic inhibitors that stimulate antigen presentation and potentiate T-cell-mediated cytotoxicity(Springer Nature, 2021) Zhou, Zhuolong; Van der Jeught, Kevin; Fang, Yuanzhang; Yu, Tao; Li, Yujing; Ao, Zheng; Liu, Sheng; Zhang, Lu; Yang, Yang; Eyvani, Haniyeh; Cox, Mary L.; Wang, Xiyu; He, Xiaoming; Ji, Guang; Schneider, Bryan P.; Guo, Feng; Wan, Jun; Zhang, Xinna; Lu, Xiongbin; Medical and Molecular Genetics, School of MedicineIn breast cancer, genetic heterogeneity, the lack of actionable targets and immune evasion all contribute to the limited clinical response rates to immune checkpoint blockade therapy. Here, we report a high-throughput screen based on the functional interaction of mouse- or patient-derived breast tumour organoids and tumour-specific cytotoxic T cells for the identification of epigenetic inhibitors that promote antigen presentation and potentiate T-cell-mediated cytotoxicity. We show that the epigenetic inhibitors GSK-LSD1, CUDC-101 and BML-210, identified by the screen, display antitumour activities in orthotopic mammary tumours in mice, that they upregulate antigen presentation mediated by the major histocompatibility complex class I on breast tumour cells and that treatment with BML-210 substantially sensitized breast tumours to the inhibitor of the checkpoint programmed death-1. Standardized measurements of tumour-cell killing activity facilitated by tumour-organoid-T-cell screens may help with the identification of candidate immunotherapeutics for a range of cancers.Item Precise targeting of POLR2A as a therapeutic strategy for human triple negative breast cancer(Springer Nature, 2019-04) Xu, Jiangsheng; Liu, Yunhua; Li, Yujing; Wang, Hai; Stewart, Samantha; Van der Jeught, Kevin; Agarwal, Pranay; Zhang, Yuntian; Liu, Sheng; Zhao, Gang; Wan, Jun; Lu, Xiongbin; He, Xiaoming; Medical and Molecular Genetics, School of MedicineTP53 is the most frequently mutated or deleted gene in triple negative breast cancer (TNBC). Both the loss of TP53 and the lack of targeted therapy are significantly correlated with poor clinical outcomes, making TNBC the only type of breast cancer that has no approved targeted therapies. Through in silico analysis, we identified POLR2A in the TP53-neighbouring region as a collateral vulnerability target in TNBC tumours, suggesting that its inhibition via small interfering RNA (siRNA) may be an amenable approach for TNBC targeted treatment. To enhance bioavailability and improve endo/lysosomal escape of siRNA, we designed pH-activated nanoparticles for augmented cytosolic delivery of POLR2A siRNA (siPol2). Suppression of POLR2A expression with the siPol2-laden nanoparticles leads to enhanced growth reduction of tumours characterized by hemizygous POLR2A loss. These results demonstrate the potential of the pH-responsive nanoparticle and the precise POLR2A targeted therapy in TNBC harbouring the common TP53 genomic alteration.Item Somatic mutation of the cohesin complex subunit confers therapeutic vulnerabilities in cancer(American Society for Clinical Investigation, 2018-07-02) Liu, Yunhua; Xu, Hanchen; Van der Jeught, Kevin; Li, Yujing; Liu, Sheng; Zhang, Lu; Fang, Yuanzhang; Zhang, Xinna; Radovich, Milan; Schneider, Bryan P.; He, Xiaoming; Huang, Cheng; Zhang, Chi; Wan, Jun; Ji, Guang; Lu, Xiongbin; Surgery, School of MedicineA synthetic lethality-based strategy has been developed to identify therapeutic targets in cancer harboring tumor-suppressor gene mutations, as exemplified by the effectiveness of poly ADP-ribose polymerase (PARP) inhibitors in BRCA1/2-mutated tumors. However, many synthetic lethal interactors are less reliable due to the fact that such genes usually do not perform fundamental or indispensable functions in the cell. Here, we developed an approach to identifying the "essential lethality" arising from these mutated/deleted essential genes, which are largely tolerated in cancer cells due to genetic redundancy. We uncovered the cohesion subunit SA1 as a putative synthetic-essential target in cancers carrying inactivating mutations of its paralog, SA2. In SA2-deficient Ewing sarcoma and bladder cancer, further depletion of SA1 profoundly and specifically suppressed cancer cell proliferation, survival, and tumorigenic potential. Mechanistically, inhibition of SA1 in the SA2-mutated cells led to premature chromatid separation, dramatic extension of mitotic duration, and consequently, lethal failure of cell division. More importantly, depletion of SA1 rendered those SA2-mutated cells more susceptible to DNA damage, especially double-strand breaks (DSBs), due to reduced functionality of DNA repair. Furthermore, inhibition of SA1 sensitized the SA2-deficient cancer cells to PARP inhibitors in vitro and in vivo, providing a potential therapeutic strategy for patients with SA2-deficient tumors.Item Targeted immunotherapy for HER2-low breast cancer with 17p loss(American Association for the Advancement of Science, 2021-02-10) Li, Yujing; Sun, Yifan; Kulke, Michael; Hechler, Torsten; Van der Jeught, Kevin; Dong, Tianhan; He, Bin; Miller, Kathy D.; Radovich, Milan; Schneider, Bryan P.; Pahl, Andreas; Zhang, Xinna; Lu, Xiongbin; Medical and Molecular Genetics, School of MedicineThe clinical challenge for treating HER2 (human epidermal growth factor receptor 2)-low breast cancer is the paucity of actionable drug targets. HER2-targeted therapy often has poor clinical efficacy for this disease due to the low level of HER2 protein on the cancer cell surface. We analyzed breast cancer genomics in the search for potential drug targets. Heterozygous loss of chromosome 17p is one of the most frequent genomic events in breast cancer, and 17p loss involves a massive deletion of genes including the tumor suppressor TP53 Our analyses revealed that 17p loss leads to global gene expression changes and reduced tumor infiltration and cytotoxicity of T cells, resulting in immune evasion during breast tumor progression. The 17p deletion region also includes POLR2A, a gene encoding the catalytic subunit of RNA polymerase II that is essential for cell survival. Therefore, breast cancer cells with heterozygous loss of 17p are extremely sensitive to the inhibition of POLR2A via a specific small-molecule inhibitor, α-amanitin. Here, we demonstrate that α-amanitin-conjugated trastuzumab (T-Ama) potentiated the HER2-targeted therapy and exhibited superior efficacy in treating HER2-low breast cancer with 17p loss. Moreover, treatment with T-Ama induced immunogenic cell death in breast cancer cells and, thereby, delivered greater efficacy in combination with immune checkpoint blockade therapy in preclinical HER2-low breast cancer models. Collectively, 17p loss not only drives breast tumorigenesis but also confers therapeutic vulnerabilities that may be used to develop targeted precision immunotherapy.Item Targeting 17q23 amplicon to overcome the resistance to anti-HER2 therapy in HER2+ breast cancer(Nature Research, 2018-11-09) Liu, Yunhua; Xu, Jiangsheng; Choi, Hyun Ho; Han, Cecil; Fang, Yuanzhang; Li, Yujing; Van der Jeught, Kevin; Xu, Hanchen; Zhang, Lu; Frieden, Michael; Wang, Lifei; Eyvani, Haniyeh; Sun, Yifan; Zhao, Gang; Zhang, Yuntian; Liu, Sheng; Wan, Jun; Huang, Cheng; Ji, Guang; Lu, Xiongbin; He, Xiaoming; Zhang, Xinna; Medical and Molecular Genetics, School of MedicineChromosome 17q23 amplification occurs in ~11% of human breast cancers. Enriched in HER2+ breast cancers, the 17q23 amplification is significantly correlated with poor clinical outcomes. In addition to the previously identified oncogene WIP1, we uncover an oncogenic microRNA gene, MIR21, in a majority of the WIP1-containing 17q23 amplicons. The 17q23 amplification results in aberrant expression of WIP1 and miR-21, which not only promotes breast tumorigenesis, but also leads to resistance to anti-HER2 therapies. Inhibiting WIP1 and miR-21 selectively inhibits the proliferation, survival and tumorigenic potential of the HER2+ breast cancer cells harboring 17q23 amplification. To overcome the resistance of trastuzumab-based therapies in vivo, we develop pH-sensitive nanoparticles for specific co-delivery of the WIP1 and miR-21 inhibitors into HER2+ breast tumors, leading to a profound reduction of tumor growth. These results demonstrate the great potential of the combined treatment of WIP1 and miR-21 inhibitors for the trastuzumab-resistant HER2+ breast cancers.