Thrombopoietin receptor-based protein-protein interaction screening (THROPPIS).

As protein-protein interactions (PPIs) are involved in many cellular events, development of mammalian cytosolic PPI detection systems is important for drug discovery as well as understanding biological phenomena. We have previously reported a c-kit-based PPI screening (KIPPIS) system, in which proteins of interest were fused with a receptor tyrosine kinase c-kit, leading to intracellular PPI-dependent cell growth. However, it has not been investigated whether PPI can be detected using other receptors. In this study, we employed a thrombopoietin receptor, which belongs to the Type I cytokine receptor family, to develop a thrombopoietin receptor-based PPI screening (THROPPIS) system. To improve the sensitivity of THROPPIS, we examined two strategies of (i) localization of the chimeric receptors on the cell membrane, and (ii) addition of a helper module to the chimeric receptors. Intriguingly, the nonlocalized chimeric receptor showed the best performance of THROPPIS. Furthermore, the addition of the helper module dramatically improved the detection sensitivity. In total, 5 peptide-domain interactions were detected successfully, demonstrating the versatility of THROPPIS. In addition, a peptide-domain interaction was detected even when insulin receptor or epidermal growth factor receptor was used as a signaling domain, demonstrating that this PPI detection system can be extended to other receptors.

Clinical outcomes and predictive value of programmed cell death-ligand 1 expression in response to anti-programmed cell death 1/ligand 1 antibodies in non-small cell lung cancer patients with performance status 2 or greater.

BACKGROUND: Anti-programmed cell death protein-1/ligand-1 (anti-PD-1/PD-L1) therapy is promising for patients with non-small-cell lung cancer (NSCLC); however, clinical trials have focused on patients with a performance status (PS) 0 or 1. This study aimed to evaluate the clinical outcomes and correlation between PD-L1 expression status and tumor response to anti-PD-1/PD-L1 therapy among NSCLC patients with poor PS (i.e., PS ≥ 2). METHODS: In total, 130 patients with NSCLC and PS ≥ 2 treated with anti-PD-1/PD-L1 monotherapy at 12 institutions between January 2016 and August 2019 were retrospectively reviewed. PD-L1 expression status was divided into four groups: < 1%, 1-49%, ≥ 50%, and unknown. RESULTS: The objective response rate and PS improvement rate were 23 and 21% and were higher in the PD-L1 ≥ 50% group than in other groups (P < 0.01). Median progression-free survival (PFS) was 62 days and was longer in the PD-L1 ≥ 50% group than in other groups (P = 0.03). Multivariate analyses revealed that PD-L1 expression is significantly associated with prolonged PFS (PD-L1 < 1%; reference; 1-49%, hazard ratio [HR] 0.19, 95% confidence interval [CI] 0.04-0.99, P = 0.05; ≥ 50%, HR 0.12, 95% CI 0.02-0.71, P = 0.02; unknown, HR 0.30, 95% CI 0.08-1.22, P = 0.09). CONCLUSIONS: NSCLC patients with poor PS and PD-L1 ≥ 50% are expected to benefit from anti-PD-1/PD-L1 therapy, despite a modest overall response among NSCLC patients with poor PS. Accordingly, PD-L1 expression provides useful information regarding decision-making for anti-PD-1/PD-L1 therapy even in these populations.

Acute Exacerbation of Idiopathic Interstitial Pneumonia in a Patient with Hepatocellular Carcinoma after Transcatheter Arterial Therapy Using Miriplatin.

A 76-year-old Japanese woman with recurrent hepatocellular carcinoma presented with acute exacerbation of idiopathic interstitial pneumonia (AE-IIP) after transcatheter arterial therapy using miriplatin. She had a history of preexisting IIP five years before presenting at our hospital. On day 4 after transcatheter arterial therapy, she complained of shortness of breath. Subsequently, she developed acute respiratory failure on day 11 after transcatheter arterial therapy. Chest computed tomography revealed extensive ground-glass opacity and traction bronchiectasis in bilateral lung fields; subsequently, she was diagnosed with AE-IIP triggered by transcatheter arterial therapy using miriplatin. Despite systemic administration of high-dose corticosteroid and cyclophosphamide, she died of respiratory failure on day 36.

A potential mechanism of the onset of acute eosinophilic pneumonia triggered by an anti-PD-1 immune checkpoint antibody in a lung cancer patient.

INTRODUCTION: The impact of immune checkpoint blockade on immunity in cancer patients is not completely elucidated due to the complexity of the immune network. Recent studies have revealed a significant role of programed cell death-ligand 2 (PD-L2) in negatively controlling the production of CD4+ T helper type 2 (Th2) cytokines and airway hypersensitiveness, suggesting hypo-responsive Th2 cells via the PD-1/PD-L2 inhibitory pathway in lung could be reawaken by PD-1 blockade therapy. METHODS: We describe the first report of acute eosinophilic pneumonia (AEP), which is known as Th2-associated pulmonary disease, triggered by nivolumab, an anti-PD-1 antibody, in an advanced non-small cell lung cancer patient. Based on the current case report and literature, the present study proposes a potential mechanism of the onset of AEP as an immune-related adverse event (irAE). RESULTS: A 62-year-old man was diagnosed with lung adenocarcinoma and nivolumab was selected as the third-line regimen. After three cycles of nivolumab treatment, chest computed tomography revealed pulmonary infiltrates in both lungs. The patient was diagnosed with AEP based on the diagnostic criteria for AEP. Nivolumab was suspended and the patient was started on oral prednisolone. His symptoms and radiological findings had rapidly improved. CONCLUSIONS: Given the increasing frequency of the use of anti-PD-1 antibodies, clinicians should be aware of the risk of AEP as a potential irAE. This study may improve our understanding of the pathophysiology underlying Th2-associated irAEs and AEP.

Severe interstitial pneumonia associated with anti-PD-1 immune checkpoint antibody after talc slurry pleurodesis.

A 70-year-old Japanese man with recurrent squamous cell carcinoma of the head and neck presented with severe interstitial pneumonia associated with nivolumab, after talc slurry pleurodesis. Following the development of malignant pleural effusion, he underwent chest drainage and was administered intrathoracic talc as a pleurodesis. Two weeks later, we administered nivolumab (3mg/kg) to be repeated every 2 weeks. However, on day 12, chest computed tomography scan demonstrated diffuse non-segmental ground-glass opacity and mild bronchiectasis. We diagnosed interstitial pneumonia associated with nivolumab. Although corticosteroid pulse therapy was initiated, the patient died of respiratory failure on day 14.

Structural basis for recognition of a kink-turn motif by an archaeal homologue of human RNase P protein Rpp38.

PhoRpp38 in the hyperthermophilic archaeon Pyrococcus horikoshii, a homologue of human ribonuclease P (RNase P) protein Rpp38, belongs to the ribosomal protein L7Ae family that specifically recognizes a kink-turn (K-turn) motif. A previous biochemical study showed that PhoRpp38 specifically binds to two stem-loops, SL12 and SL16, containing helices P12.1/12.2 and P15/16 respectively, in P. horikoshii RNase P RNA (PhopRNA). In order to gain insight into the PhoRpp38 binding mode to PhopRNA, we determined the crystal structure of PhoRpp38 in complex with the SL12 mutant (SL12M) at a resolution of 3.4 Å. The structure revealed that Lys35 on the ß-strand (ß1) and Asn38, Glu39, and Lys42 on the α-helix (α2) in PhoRpp38 interact with characteristic G•A and A•G pairs in SL12M, where Ile93, Glu94, and Val95, on a loop between α4 and ß4 in PhoRpp38, interact with the 3-nucleotide bulge (G-G-U) in the SL12M. The structure demonstrates the previously proposed secondary structure of SL12, including helix P12.2. Structure-based mutational analysis indicated that amino acid residues involved in the binding to SL12 are also responsible for the binding to SL16. This result suggested that each PhoRpp38 binds to the K-turns in SL12 and SL16 in PhopRNA. A pull-down assay further suggested the presence of a second K-turn in SL12. Based on the present results, together with available data, we discuss a structural basis for recognition of K-turn motifs in PhopRNA by PhoRpp38.