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Alternative splicing (AS) is prevalent in cancer, generating an extensive but largely unexplored repertoire of novel immunotherapy targets. We describe I soform peptides from R NA splicing for I mmunotherapy target S creening (IRIS), a computational platform capable of discovering AS-derived tumor antigens (TAs) for T cell receptor (TCR) and chimeric antigen receptor T cell (CAR-T) therapies. IRIS leverages large-scale tumor and normal transcriptome data and incorporates multiple screening approaches to discover AS-derived TAs with tumor-associated or tumor-specific expression. In a proof-of-concept analysis integrating transcriptomics and immunopeptidomics data, we showed that hundreds of IRIS-predicted TCR targets are presented by human leukocyte antigen (HLA) molecules. We applied IRIS to RNA-seq data of neuroendocrine prostate cancer (NEPC). From 2,939 NEPC-associated AS events, IRIS predicted 1,651 epitopes from 808 events as potential TCR targets for two common HLA types (A*02:01 and A*03:01). A more stringent screening test prioritized 48 epitopes from 20 events with “neoantigen-like” NEPC-specific expression. Predicted epitopes are often encoded by microexons of ≤30 nucleotides. To validate the immunogenicity and T cell recognition of IRIS-predicted TCR epitopes, we performed in vitro T cell priming in combination with single-cell TCR sequencing. Seven TCRs transduced into human peripheral blood mononuclear cells (PBMCs) showed high activity against individual IRIS-predicted epitopes, providing strong evidence of isolated TCRs reactive to AS-derived peptides. One selected TCR showed efficient cytotoxicity against target cells expressing the target peptide. Our study illustrates the contribution of AS to the TA repertoire of cancer cells and demonstrates the utility of IRIS for discovering AS-derived TAs and expanding cancer immunotherapies.

The ability to selectively bind to antigenic peptides and secrete cytokines can define populations of cells with therapeutic potential in emerging T cell receptor (TCR) immunotherapies. We leverage cavity-containing hydrogel microparticles, called nanovials, each coated with millions of peptide-major histocompatibility complex (pMHC) monomers to isolate antigen-reactive T cells. T cells are captured and activated by pMHCs and secrete cytokines on nanovials, allowing sorting based on both affinity and function. The TCRs of sorted cells on nanovials are sequenced, recovering paired αβ-chains using microfluidic emulsion-based single-cell sequencing. By labeling nanovials having different pMHCs with unique oligonucleotide-barcodes we could link TCR sequence to targets with 100% accuracy. We identified with high specificity an expanded repertoire of functional TCRs targeting viral antigens compared to standard techniques.One-sentence SummaryAffinity and secretion-based screening of antigen-specific T cells using nanovials defines a functional TCR repertoire

Herein, we report the design and synthesis of inhibitors of Mycobacterium tuberculosis (Mtb) phospho-MurNAc-pentapeptide translocase I (MurX), the first membrane-associated step of peptidoglycan synthesis, leveraging the privileged structure of the sansanmycin family of uridylpeptide natural products. A number of analogues bearing hydrophobic amide modifications to the pseudo-peptidic end of the natural product scaffold were generated that exhibited nanomolar inhibitory activity against Mtb MurX and potent activity against Mtb in vitro. We show that a lead analogue bearing an appended neopentylamide moiety possesses rapid antimycobacterial effects with a profile similar to the frontline tuberculosis drug isoniazid. This molecule was also capable of inhibiting Mtb growth in macrophages where mycobacteria reside in vivo and reduced mycobacterial burden in an in vivo zebrafish model of tuberculosis.

Tissue-specific antigens can serve as targets for adoptive T cell transfer-based cancer immunotherapy. Recognition of tumor by T cells is mediated by interaction between peptide–major histocompatibility complexes (pMHCs) and T cell receptors (TCRs). Revealing the identity of peptides bound to MHC is critical in discovering cognate TCRs and predicting potential toxicity. We performed multimodal immunopeptidomic analyses for human prostatic acid phosphatase (PAP), a well-recognized tissue antigen. Three physical methods, including mild acid elution, coimmunoprecipitation, and secreted MHC precipitation, were used to capture a thorough signature of PAP on HLA-A*02:01. Eleven PAP peptides that are potentially A*02:01-restricted were identified, including five predicted strong binders by NetMHCpan 4.0. Peripheral blood mononuclear cells (PBMCs) from more than 20 healthy donors were screened with the PAP peptides. Seven cognate TCRs were isolated which can recognize three distinct epitopes when expressed in PBMCs. One TCR shows reactivity toward cell lines expressing both full-length PAP and HLA-A*02:01. Our results show that a combined multimodal immunopeptidomic approach is productive in revealing target peptides and defining the cloned TCR sequences reactive with prostatic acid phosphatase epitopes.

Herein, we report the design and synthesis of inhibitors of

Small cell carcinomas of the lung, bladder, and prostate share similar transcription patterns and drug sensitivities. Due to their high cellular plasticity, these cancers often escape treatment through a trans-differentiation from adenocarcinoma to the neuroendocrine state. We previously developed a pan small cell cancer in vitro/in vivo model named PARCB that can recapitulate this transition from primary patient tissues. To understand which transcription factors may be important in this transition, we conducted bulk and single cell RNA sequencing over time. We identified a developmental trajectory that is shared among all samples and is defined by stage-specific transcription factors. We plan to interrogate the role that these transcription factors play in the PARCB transformation assay. We performed ATAC sequencing to investigate how these transcription factors regulate these transitional states. Our study will provide a basic understanding of the transcriptional changes that occur during neuroendocrine differentiation and provide new potential therapeutic targets for small cell cancers. Citation Format: Chia-Chun Chen, Kai Song, Wendy Tran, Matthew Obusan, Tyler Sugimoto, Katherine Sheu, Donghui Cheng, Grigor Varuzhanyan, Liang Wang, Lisa Ta, Zhiyuan Mao, Nathanael Bangayan, Jung-Wook Park, Thomas Graerber, Owen Witte. Elucidating transcriptional dynamics in neuroendocrine differentiation of advanced prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 789.

Many aggressive epithelial cancers do not carry targetable driver mutations (Mendiratta et al. 2021, NCI-MATCH Clinical trial NCT02465060). Commonly altered signaling pathways highlight the propensity for tumors to depend on such pathways for growth and survival where genomic alterations may not be required for pathway activation. The Raf family kinases are crucial mediators of the Ras/Raf/MEK/ERK (MAPK) cascade, which has been shown to be upregulated in a subset of metastatic cancers and are mutated in many epithelial cancers. A recent study suggests non-mutated C-Raf can drive metastasis to the lungs, bone, and various other tissues (Faltermeir et al. 2016). Though the mechanism of C-Raf driven metastasis is likely through MAPK activation, C-Raf has been demonstrated to possess MAPK independent roles that may also contribute to this phenotype. In this study, we explored various C-Raf functions as drivers of metastasis in an intracardiac mouse model system. Using a series of Raf knock-out cell lines and mutants targeting functional residues in C-Raf, we demonstrated that C-Raf dimerization is necessary to drive metastasis. We further showed that the metastasis-promoting activity of C-Raf is dependent on co-expression of its family member, B-Raf, for an accelerated metastatic phenotype. However, overexpression of a kinase-dead C-Raf mutant was still able to produce metastases albeit with lower efficiency, suggesting C-Raf possesses non-kinase dependent functions that also contributed to metastasis. Together, these results point to the importance of Raf non-canonical roles in oncogenic processes that may be unappreciated in metastatic disease. Citation Format: Lisa H. Ta, Janai R. Carr-Ascher, Weixian Deng, Brandon L. Tsai, Wendy Tran, Donny Gun, Donghui Cheng, Jihui Sha, Yeonjoo Hwang, John W. Phillips, Matthew B. Obusan, Nathanael J. Bangayan, Miyako Noguchi, Zhiyuan Mao, Chia-Chun Chen, Liang Wang, Grigor Varuzhanyan, John D. Gordon, James W. Wohlschlegel, Owen N. Witte. Determining the role of non-mutated C-Raf kinase in metastatic disease [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2438.

The ohmyungsamycin and ecumicin natural product families are structurally related cyclic depsipeptides that display potent antimycobacterial activity. Herein the total syntheses of ohmyungsamycin A, deoxyecumicin, and ecumicin are reported, together with the direct biological comparison of members of these natural product families against Mycobacterium tuberculosis (Mtb), the etiological agent of tuberculosis (TB). The synthesis of each of the natural products employed a solid-phase strategy to assemble the linear peptide precursor, involving a key on-resin esterification and an optional on-resin dimethylation step, before a final solution-phase macrolactamization between the non-proteinogenic N-methyl-4-methoxy-l-tryptophan amino acid and a bulky N-methyl-l-valine residue. The synthetic natural products possessed potent antimycobacterial activity against Mtb with MIC90 's ranging from 110-360 nm and retained activity against Mtb in Mtb-infected macrophages. Deoxyecumicin also exhibited rapid bactericidal killing against Mtb, sterilizing cultures after 21 days.

Zinc–air batteries (ZABs), which employ oxygen from air for the reduction reaction or discharging, have several benefits, such as high energy density, operational safety, environmental compatibility and low cost. Primary ZABs are a mature technology; however, rechargeable battery design and structure need to be optimized to achieve better cycle life. Two different configurations for a tri-electrode, rechargeable battery with poly(acrylic acid) (PAA) have been developed in this work; i.e., a planar cell and a sandwich cell. Charge-discharge cycling tests at 5 mA-cm–2 show that the sandwich cell is more suitable for ZABs than the planar cell. Various additives for the PAA, such as cross linking agents and ZnO, have also been evaluated using the tri-electrode design. The addition of ZnO to the oxygen reduction reaction side of the battery enhances the cycling performance of ZABs, i.e., the battery can withstand at least 100 cycles at 5 mA cm–2 with initial efficiency of 62%.

Solid state potassium ion selective electrode (K+ ISE) has been the epitome of the most studied chemical sensors in recent years due to its practical importance in biomedical applications. In fact, potassium monitoring in food and serum, urine, and potentially in brain has been carried out in the clinical and medical fields to reveal physical conditions of the patients such as renal diseases, hypopotassemia, alkalosis, cirrhosis of liver, etc. In this report, we developed an electrochemical sensing unit which working, counter and reference electrodes are integrated in a single plane as all-solid-state form. Here, a polyaniline intermediate layer and salt-saturated polyvinylebutyral top coating are introduced in the working and reference electrodes, respectively, in order to mitigate the output potential drift problem that prevented widespread use of solid-state K+ ISE. Morphological and electrochemical properties of K+ ISE are studied by using a scanning electron microscope (SEM) and a potentiostat, respectively. Various measurement modes of electrochemical measurements, including cyclic voltammetry (CV), chronopotentiometry (CP), and electrochemical impedance spectroscopy (EIS), are implemented. The K+ ISE show desirable properties including high sensitivity (60.5 mV/decade), low concentration for the limit of detection (10-5.8 M), and large range of linear detection (10-5 – 1 M). Selectivity of our of K+ ISE against NH4 + , Na+ , Mg2+ , Ca2+ , and Fe3+ was studied. With its high potential to be miniaturized, we foresee that our solid-state K+ ISE will find future applications in microdevices for clinical analysis, agricultural and, environmental applications.