Neurofibromatosis type 1 (NF1) is a common tumor predisposition syndrome, caused by NF1 gene mutation, in which affected patients develop Schwann cell lineage peripheral nerve sheath tumors (neurofibromas). To investigate human neurofibroma pathogenesis, we differentiated a series of isogenic patient-specific NF1-mutant human induced-pluripotent stem cells (hiPSCs) into Schwannian lineage cells (SLCs). We found that while wild-type and heterozygous NF1-mutant hiPSC-SLCs did not form tumors following mouse sciatic nerve implantation, NF1-null SLCs formed bona fide neurofibromas with high levels of SOX10 expression. To confirm that SOX10+ SLCs contain the cells of origin for neurofibromas, both Nf1 alleles were inactivated in mouse Sox10+ cells, leading to classic nodular cutaneous and plexiform neurofibroma formation that completely recapitulate their human counterparts. Moreover, we discovered that NF1 loss impaired Schwann cell differentiation by inducing a persistent stem-like state to expand the pool of progenitors required to initiate tumor formation, indicating that in addition to regulating MAPK-mediated cell growth, NF1 loss also alters Schwann cell differentiation to promote neurofibroma development. Taken together, we established complementary humanized neurofibroma explant and first-in-kind mouse genetically engineered nodular cutaneous neurofibroma models that delineate neurofibroma pathogenesis amenable to future therapeutic target discovery and evaluation.
Juan Mo, Corina Anastasaki, Zhiguo Chen, Tracey Shipman, Jason B. Papke, Kevin Y. Yin, David H. Gutmann, Lu Q. Le
MYC stimulates both metabolism and protein synthesis, but it is unknown how cells coordinate these complementary programs. Previous work reported that in a subset of small cell lung cancer (SCLC) cell lines, MYC activates guanosine triphosphate (GTP) synthesis and results in sensitivity to inhibitors of the GTP synthesis enzyme inosine monophosphate dehydrogenase (IMPDH). Here we demonstrated that primary MYCHigh human SCLC tumors also contain abundant guanosine nucleotides. We also found that elevated MYC in SCLCs with acquired chemoresistance rendered these otherwise recalcitrant tumors dependent on IMPDH. Unexpectedly, our data indicated that IMPDH links the metabolic and protein synthesis outputs of oncogenic MYC. Co-expression analysis placed IMPDH within the MYC-driven ribosome program, and GTP depletion prevented RNA Polymerase I (Pol I) from localizing to ribosomal DNA. Furthermore, the GTPases GPN1 and GPN3 were upregulated by MYC and directed Pol I to ribosomal DNA. Constitutively GTP-bound GPN1/3 mutants mitigated the effect of GTP depletion on Pol I, protecting chemoresistant SCLC cells from IMPDH inhibition. GTP therefore functions as a metabolic gate tethering MYC-dependent ribosome biogenesis to nucleotide sufficiency through GPN1 and GPN3. IMPDH dependence is a targetable vulnerability in chemoresistant, MYCHigh SCLC.
Fang Huang, Kenneth Huffman, Zixi Wang, Xun Wang, Kailong Li, Feng Cai, Chendong Yang, Ling Cai, Terry S. Shih, Lauren G. Zacharias, Andrew S. Chung, Qian Yang, Milind D. Chalishazar, Abbie S. Ireland, C. Allison Stewart, Kasey R. Cargill, Luc Girard, Yi Liu, Min Ni, Jian Xu, Xudong Wu, Hao Zhu, Benjamin J. Drapkin, Lauren A. Byers, Trudy G. Oliver, Adi Gazdar, John Minna, Ralph DeBerardinis
Mutations in the core RNA splicing factor SF3B1 are prevalent in leukemias and uveal melanoma but hotspot SF3B1 mutations are also seen in epithelial malignancies such as breast cancer. Although hotspot mutations in SF3B1 alter hematopoietic differentiation, whether SF3B1 mutations contribute to epithelial cancer development and progression is unknown. Here, we identify that SF3B1 mutations in mammary epithelial and breast cancer cells induce a recurrent pattern of aberrant splicing leading to activation of AKT and NF-kB, enhanced cell migration, and accelerated tumorigenesis. Transcriptomic analysis of human cancer specimens, MMTV-cre Sf3b1K700E/WT mice, and isogenic mutant cell lines identified hundreds of aberrant 3’ splice sites (3’ss) induced by mutant SF3B1. Consistently between mouse and human tumors, mutant SF3B1 promoted aberrant splicing (dependent on aberrant branchpoints as well as pyrimidines downstream of the cryptic 3’ss) and consequent suppression of PPP2R5A and MAP3K7, critical negative regulators of AKT and NF-kB. Coordinate activation of NF-kB and AKT signaling was observed in the knock-in models, leading to accelerated cell migration and tumor development in combination with mutant PIK3CA but also hypersensitizing cells to AKT kinase inhibitors. These data identify hotspot mutations in SF3B1 as an important contributor to breast tumorigenesis and reveal unique vulnerabilities in cancers harboring them.
Bo Liu, Zhaoqi Liu, Sisi Chen, Michelle Ki, Caroline Erickson, Jorge S. Reis-Filho, Benjamin H. Durham, Qing Chang, Elisa de Stanchina, Yiwei Sun, Raul Rabadan, Omar Abdel-Wahab, Sarat Chandarlapaty
BACKGROUND Therapeutic vaccinations against cancer have mainly targeted differentiation antigens, cancer-testis antigens, and overexpressed antigens and have thus far resulted in little clinical benefit. Studies conducted by multiple groups have demonstrated that T cells recognizing neoantigens are present in most cancers and offer a specific and highly immunogenic target for personalized vaccination.METHODS We recently developed a process using tumor-infiltrating lymphocytes to identify the specific immunogenic mutations expressed in patients’ tumors. Here, validated, defined neoantigens, predicted neoepitopes, and mutations of driver genes were concatenated into a single mRNA construct to vaccinate patients with metastatic gastrointestinal cancer.RESULTS The vaccine was safe and elicited mutation-specific T cell responses against predicted neoepitopes not detected before vaccination. Furthermore, we were able to isolate and verify T cell receptors targeting KRASG12D mutation. We observed no objective clinical responses in the 4 patients treated in this trial.CONCLUSION This vaccine was safe, and potential future combination of such vaccines with checkpoint inhibitors or adoptive T cell therapy should be evaluated for possible clinical benefit in patients with common epithelial cancers.TRIAL REGISTRATION Phase I/II protocol (NCT03480152) was approved by the IRB committee of the NIH and the FDA.FUNDING Center for Clinical Research, NCI, NIH.
Gal Cafri, Jared J. Gartner, Tal Zaks, Kristen Hopson, Noam Levin, Biman C. Paria, Maria R. Parkhurst, Rami Yossef, Frank J. Lowery, Mohammad S. Jafferji, Todd D. Prickett, Stephanie L. Goff, Christine T. McGowan, Samantha Seitter, Mackenzie L. Shindorf, Anup Parikh, Praveen D. Chatani, Paul F. Robbins, Steven A. Rosenberg
Glioblastoma multiforme (GBM) heterogeneity causes a greater number of deaths than any other brain tumor, despite the availability of alkylating chemotherapy. GBM stem-like cells (GSCs) contribute to GBM complexity and chemoresistance, but it remains challenging to identify and target GSCs or factors that control their activity. Here, we identified a specific GSC subset and show that activity of these cells is positively regulated by stabilization of methyl CpG binding domain 3 (MBD3) protein. MBD3 binds to CK1A and to BTRCP E3 ubiquitin ligase, triggering MBD3 degradation, suggesting that modulating this circuit could antagonize GBM recurrence. Accordingly, xenograft mice treated with the CK1A activator pyrvinium pamoate (Pyr-Pam) showed enhanced MBD3 degradation in cells expressing high levels of O6-methylguanine-DNA methyltransferase (MGMT) and in GSCs, overcoming temozolomide chemoresistance. Pyr-Pam blocked recruitment of MBD3 and the repressive nucleosome remodeling and deacetylase (NuRD) complex to neurogenesis-associated gene loci and increased acetyl–histone H3 activity and GSC differentiation. We conclude that CK1A/BTRCP/MBD3/NuRD signaling modulates GSC activation and malignancy, and that targeting this signaling could suppress GSC proliferation and GBM recurrence.
Byoung-San Moon, Mingyang Cai, Grace Lee, Tong Zhao, Xiaofeng Song, Steven L. Giannotta, Frank J. Attenello, Min Yu, Wange Lu
Angiosarcomas are rare, clinically aggressive tumors with limited treatment options and a dismal prognosis. We analyzed angiosarcomas from 68 patients, integrating information from multiomic sequencing, NanoString immuno-oncology profiling, and multiplex immunohistochemistry and immunofluorescence for tumor-infiltrating immune cells. Through whole-genome sequencing (n = 18), 50% of the cutaneous head and neck angiosarcomas exhibited higher tumor mutation burden (TMB) and UV mutational signatures; others were mutationally quiet and non–UV driven. NanoString profiling revealed 3 distinct patient clusters represented by lack (clusters 1 and 2) or enrichment (cluster 3) of immune-related signaling and immune cells. Neutrophils (CD15+), macrophages (CD68+), cytotoxic T cells (CD8+), Tregs (FOXP3+), and PD-L1+ cells were enriched in cluster 3 relative to clusters 2 and 1. Likewise, tumor inflammation signature (TIS) scores were highest in cluster 3 (7.54 vs. 6.71 vs. 5.75, respectively; P < 0.0001). Head and neck angiosarcomas were predominant in clusters 1 and 3, providing the rationale for checkpoint immunotherapy, especially in the latter subgroup with both high TMB and TIS scores. Cluster 2 was enriched for secondary angiosarcomas and exhibited higher expression of DNMT1, BRD3/4, MYC, HRAS, and PDGFRB, in keeping with the upregulation of epigenetic and oncogenic signaling pathways amenable to targeted therapies. Molecular and immunological dissection of angiosarcomas may provide insights into opportunities for precision medicine.
Jason Yongsheng Chan, Jing Quan Lim, Joe Yeong, Vinod Ravi, Peiyong Guan, Arnoud Boot, Timothy Kwang Yong Tay, Sathiyamoorthy Selvarajan, Nur Diyana Md Nasir, Jie Hua Loh, Choon Kiat Ong, Dachuan Huang, Jing Tan, Zhimei Li, Cedric Chuan-Young Ng, Thuan Tong Tan, Mikio Masuzawa, Ken Wing-Kin Sung, Mohamad Farid, Richard Hong Hui Quek, Ngian Chye Tan, Melissa Ching Ching Teo, Steven George Rozen, Patrick Tan, Andrew Futreal, Bin Tean Teh, Khee Chee Soo
The undruggable nature of oncogenic Myc transcription factors poses a therapeutic challenge in neuroblastoma, a pediatric cancer in which MYCN amplification is strongly associated with unfavorable outcome. Here, we show that CYC065 (fadraciclib), a clinical inhibitor of CDK9 and CDK2, selectively targeted MYCN-amplified neuroblastoma via multiple mechanisms. CDK9 — a component of the transcription elongation complex P-TEFb — bound to the MYCN-amplicon superenhancer, and its inhibition resulted in selective loss of nascent MYCN transcription. MYCN loss led to growth arrest, sensitizing cells for apoptosis following CDK2 inhibition. In MYCN-amplified neuroblastoma, MYCN invaded active enhancers, driving a transcriptionally encoded adrenergic gene expression program that was selectively reversed by CYC065. MYCN overexpression in mesenchymal neuroblastoma was sufficient to induce adrenergic identity and sensitize cells to CYC065. CYC065, used together with temozolomide, a reference therapy for relapsed neuroblastoma, caused long-term suppression of neuroblastoma growth in vivo, highlighting the clinical potential of CDK9/2 inhibition in the treatment of MYCN-amplified neuroblastoma.
Evon Poon, Tong Liang, Yann Jamin, Susanne Walz, Colin Kwok, Anne Hakkert, Karen Barker, Zuzanna Urban, Khin Thway, Rhamy Zeid, Albert Hallsworth, Gary Box, Marli E. Ebus, Marco P. Licciardello, Yordan Sbirkov, Glori Lazaro, Elizabeth Calton, Barbara M. Costa, Melanie Valenti, Alexis De Haven Brandon, Hannah Webber, Nicolas Tardif, Gilberto S. Almeida, Rossitza Christova, Gunther Boysen, Mark W. Richards, Giuseppe Barone, Anthony Ford, Richard Bayliss, Paul A. Clarke, Johann De Bono, Nathanael S. Gray, Julian Blagg, Simon P. Robinson, Suzanne A. Eccles, Daniella Zheleva, James E. Bradner, Jan Molenaar, Igor Vivanco, Martin Eilers, Paul Workman, Charles Y. Lin, Louis Chesler
Protein tyrosine phosphatase non-receptor type 2 (PTPN2) recently emerged as a promising cancer immunotherapy target. We set to investigate the functional role of PTPN2 in the pathogenesis of human colorectal carcinoma (CRC) as its role in immune-silent solid tumors is poorly understood. We demonstrate that in human CRC, increased PTPN2 expression and activity correlated with disease progression and decreased immune responses in tumor tissues. Particularly, stage II and III tumors displayed enhanced PTPN2 protein expression in tumor-infiltrating T-cells and increased PTPN2 levels negatively correlated with PD1, CTLA4, STAT1 and granzyme A. In vivo, T-cell and dendritic cell-specific PTPN2 deletion reduced tumor burden in several CRC models by promoting CD44+ effector/memory T-cells, as well as CD8+ T-cell infiltration and cytotoxicity into the tumor. In direct relevance to CRC treatment, T-cell-specific PTPN2 deletion potentiated anti-PD-1 efficacy and induced anti-tumor memory formation upon tumor re-challenge in vivo. Our data suggest a role for PTPN2 in suppressing anti-tumor immunity and promoting tumor development in CRC patients. Our in vivo results uncover PTPN2 as a key player in controlling immunogenicity of CRC, with the strong potential to be exploited to promote cancer immunotherapy.
Egle Katkeviciute, Larissa Hering, Ana Montalban-Arques, Philipp Busenhart, Marlene Schwarzfischer, Roberto Manzini, Javier Conde, Kirstin Atrott, Silvia Lang, Gerhard Rogler, Elisabeth Naschberger, Vera S. Schellerer, Michael Stürzl, Andreas Rickenbacher, Matthias Turina, Achim Weber, Sebastian Leibl, Gabriel E. Leventhal, Mitchell Levesque, Onur Boyman, Michael Scharl, Marianne R. Spalinger
Immune evasion is a pivotal event in tumor progression. To eliminate human cancer cells, current immune checkpoint therapy is set to boost the 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 towards 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.
Yuanzhang Fang, Lifei Wang, Changlin Wan, Yifan Sun, Kevin Van der Jeught, Zhuolong Zhou, Tianhan Dong, Ka Man So, Tao Yu, Yujing Li, Haniyeh Eyvani, Austyn Colter, Edward Dong, Sha Cao, Jin Wang, Bryan P. Schneider, George Sandusky, Yunlong Liu, Chi Zhang, Xiongbin Lu, Xinna Zhang
Diffuse intrinsic pontine glioma (DIPG) kills more children than any other type of brain tumor. Despite clinical trials testing many chemotherapeutic agents, palliative radiotherapy remains the standard treatment. Here, we utilized Cre/loxP technology to show that deleting Ataxia telangiectasia mutated (Atm) in primary mouse models of DIPG can enhance tumor radiosensitivity. Genetic deletion of Atm improved survival of mice with p53 deficient but not p53 wild-type gliomas following radiotherapy. Similar to patients with DIPG, mice with p53 wild-type tumors had improved survival after radiotherapy independent of Atm deletion. Primary p53 wild-type tumor cell lines induced proapoptotic genes after radiation and repressed the NRF2 target, NAD(P)H quinone dehydrogenase 1 (Nqo1). Tumors lacking p53 and Ink4a/Arf expressed the highest level of Nqo1 and were most resistant to radiation, but deletion of Atm enhanced the radiation response. These results suggest that tumor genotype may determine whether inhibition of ATM during radiotherapy will be an effective clinical approach to treat DIPGs.
Katherine Deland, Bryce F. Starr, Joshua S. Mercer, Jovita Byemerwa, Donna M. Crabtree, Nerissa T. Williams, Lixia Luo, Yan Ma, Mark Chen, Oren J. Becher, David G Kirsch