Protein&Cell

2018 Vol. 9, No. 10

Base editors which enable highly efficient nucleotide substitutions without inducing DNA double-strand breaks have promising potential applications in various fields. In this issue of Protein & Cell, two independent  groups  demonstra-
ted highly efficient “A” to “G” conversions in mouse and rat embryos using the adenine base editor (ABE) technology. With the help of this  powerful  tool,  Liang
et  al.  successfully  generated  a
new mouse Dunchenne muscular dystrophy (DMD) model by mutating the base pairs involved in DMD gene mRNA splicing. In addition to making mouse and rat models using the ABE technology, Yang et al. reported expansion of the ABE targeting scope by fusion of the edTadA with different Cas9 variants. Moreover, they also demonstrated their method of increasing the ABE efficiency via using the chemically modified guide RNAs.

Recollection

A tribute to my supervisor Professor Zhengyi Wu

Zhekun Zhou

2018, 9(10): 827-831. doi: 10.1007/s13238-018-0565-0

[Abstract](460) [PDF 4012KB](384)

Abstract:

Commentary

IFN-λ: A new spotlight in innate immunity against influenza virus infection

Yeping Sun, Jingwen Jiang, Po Tien, Wenjun Liu, Jing Li

2018, 9(10): 832-837. doi: 10.1007/s13238-017-0503-6

[Abstract](484) [PDF 3056KB](1414)

Abstract:

Research articles

Phase I study of chimeric antigen receptor modified T cells in treating HER2-positive advanced biliary tract cancers and pancreatic cancers

Kaichao Feng, Yang Liu, Yelei Guo, Jingdan Qiu, Zhiqiang Wu, Hanren Dai, Qingming Yang, Yao Wang, Weidong Han

2018, 9(10): 838-847. doi: 10.1007/s13238-017-0440-4

[Abstract](522) [PDF 1819KB](2007)

Abstract:
This phase I clinical trial (NCT01935843) is to evaluate the safety, feasibility, and activity of chimeric antigen receptor-engineered T cell (CART) immunotherapy targeting human epidermal growth factor receptor 2 (HER2) in patients with advanced biliary tract cancers (BTCs) and pancreatic cancers (PCs). Eligible patients with HER2-positive (>50%) BTCs and PCs were enrolled in the trial. Well cultured CART-HER2 cells were infused following the conditioning treatment composed of nabpaclitaxel (100-200 mg/m²) and cyclophosphamide (15-35 mg/kg). CAR transgene copy number in the peripheral blood was serially measured to monitor the expansion and persistence of CART-HER2 cells in vivo. Eleven enrolled patients received 1 to 2-cycle CARTHER2 cell infusion (median CAR⁺ T cell 2.1×10⁶/kg). The conditioning treatment resulted in mild-to-moderate fatigue, nausea/vomiting, myalgia/arthralgia, and lymphopenia. Except one grade-3 acute febrile syndrome and one abnormal elevation of transaminase (>9 ULN), adverse events related to the infusion of CART-HER2 cells were mild-to-moderate. Post-infusion toxicities included one case of reversible severe upper gastrointestinal hemorrhage which occurred in a patient with gastric antrum invaded by metastasis 11 days after the CART-HER2 cell infusion, and 2 cases of grade 1-2 delayed fever, accompanied by the release of C-reactive protein and interleukin-6. All patients were evaluable for assessment of clinical response, among which 1 obtained a 4.5-months partial response and 5 achieved stable disease. The median progression free survival was 4.8 months (range, 1.5-8.3 months). Finally, data from this study demonstrated the safety and feasibility of CART-HER2 immunotherapy, and showed encouraging signals of clinical activity.

TDP-43 regulates cancer-associated microRNAs

Xiaowei Chen, Zhen Fan, Warren McGee, Mengmeng Chen, Ruirui Kong, Pushuai Wen, Tengfei Xiao, Xiaomin Chen, Jianghong Liu, Li Zhu, Runsheng Chen, Jane Y. Wu

2018, 9(10): 848-866. doi: 10.1007/s13238-017-0480-9

[Abstract](552) [PDF 3496KB](1516)

Abstract:
Aberrant regulation of miRNA genes contributes to pathogenesis of a wide range of human diseases, including cancer. The TAR DNA binding protein 43 (TDP-43), a RNA/DNA binding protein associated with neurodegeneration, is involved in miRNA biogenesis. Here, we systematically examined miRNAs regulated by TDP-43 using RNA-Seq coupled with an siRNA-mediated knockdown approach. TDP-43 knockdown affected the expression of a number of miRNAs. In addition, TDP-43 down-regulation led to alterations in the patterns of different isoforms of miRNAs (isomiRs) and miRNA arm selection, suggesting a previously unknown role of TDP-43 in miRNA processing. A number of TDP-43 associated miRNAs, and their candidate target genes, are associated with human cancers. Our data reveal highly complex roles of TDP-43 in regulating different miRNAs and their target genes. Our results suggest that TDP-43 may promote migration of lung cancer cells by regulating miR-423-3p. In contrast, TDP-43 increases miR-500a-3p expression and binds to the mature miR-500a-3p sequence. Reduced expression of miR-500a-3p is associated with poor survival of lung cancer patients, suggesting that TDP-43 may have a suppressive role in cancer by regulating miR-500a-3p. Cancer-associated genes LIF and PAPPA are possible targets of miR-500a-3p. Our work suggests that TDP-43-regulated miRNAs may play multifaceted roles in the pathogenesis of cancer.

Effective and persistent antitumor activity of HER2-directed CAR-T cells against gastric cancer cells in vitro and xenotransplanted tumors in vivo

Yanjing Song, Chuan Tong, Yao Wang, Yunhe Gao, Hanren Dai, Yelei Guo, Xudong Zhao, Yi Wang, Zizheng Wang, Weidong Han, Lin Chen

2018, 9(10): 867-878. doi: 10.1007/s13238-017-0384-8

[Abstract](472) [PDF 3966KB](2527)

Abstract:
Human epidermal growth factor receptor 2 (HER2) proteins are overexpressed in a high proportion of gastric cancer (GC) cases and affect the maintenance of cancer stem cell (CSC) subpopulations, which are used as targets for the clinical treatment of patients with HER2-positive GC. Despite improvements in survival, numerous HER2-positive patients fail treatment with trastuzumab, highlighting the need for more effective therapies. In this study, we generated a novel type of genetically modified human T cells, expressing a chimeric antigen receptor (CAR), and targeting the GC cell antigen HER2, which harbors the CD137 and CD3ζ moieties. Our findings show that the expanded CAR-T cells, expressing an increased central memory phenotype, were activated by the specific recognition of HER2 antigens in an MHC-independent manner, and effectively killed patient-derived HER2-positive GC cells. In HER2-positive xenograft tumors, CAR-T cells exhibited considerably enhanced tumor inhibition ability, long-term survival, and homing to targets, compared with those of non-transduced T cells. The sphere-forming ability and in vivo tumorigenicity of patient-derived gastric cancer stem-like cells, expressing HER2 and the CD44 protein, were also inhibited. Our results support the future development and clinical application of this adoptive immunotherapy in patients with HER2-positive advanced GC.

SCF^β-TRCP E3 ubiquitin ligase targets the tumor suppressor ZNRF3 for ubiquitination and degradation

Yanpeng Ci, Xiaoning Li, Maorong Chen, Jiateng Zhong, Brian J. North, Hiroyuki Inuzuka, Xi He, Yu Li, Jianping Guo, Xiangpeng Dai

2018, 9(10): 879-889. doi: 10.1007/s13238-018-0510-2

[Abstract](656) [PDF 3008KB](870)

Abstract:
Wnt signaling has emerged as a major regulator of tissue development by governing the self-renewal and maintenance of stem cells in most tissue types. As a key upstream regulator of the Wnt pathway, the transmembrane E3 ligase ZNRF3 has recently been established to play a role in negative regulation of Wnt signaling by targeting Frizzled (FZD) receptor for ubiquitination and degradation. However, the upstream regulation of ZNRF3, in particular the turnover of ZNRF3, is still unclear. Here we report that ZNRF3 is accumulated in the presence of proteasome inhibitor treatment independent of its E3-ubiquitin ligase activity. Furthermore, the Cullin 1-specific SCF complex containing β-TRCP has been identified to directly interact with and ubiquitinate ZNRF3 thereby regulating its protein stability. Similar with the degradation of β-catenin by β-TRCP, ZNRF3 is ubiquitinated by β-TRCP in both CKI-phosphorylation-and degron-dependent manners. Thus, our findings not only identify a novel substrate for β-TRCP oncogenic regulation, but also highlight the dual regulation of Wnt signaling by β-TRCP in a contextdependent manner where β-TRCP negatively regulates Wnt signaling by targeting β-catenin, and positively regulates Wnt signaling by targeting ZNRF3.

Letters

Mechanism of actions of Oncocin, a prolinerich antimicrobial peptide, in early elongation revealed by single-molecule FRET