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Tyrosine kinase inhibitors (TKIs) that target the ROS proto-oncogene 1, receptor tyrosine kinase (ROS1) gene have shown dramatic therapeutic effects in patients with ROS1-rearranged non-small-cell lung cancer (NSCLC). Nevertheless, advanced ROS1-rearranged NSCLC is rarely cured as a portion of the tumor cells can survive the initial stages of ROS1-TKI treatment, even after maximum tumor shrinkage. Therefore, understanding the mechanisms underlying initial cell survival during ROS1-TKI treatment is necessary to prevent cell survival and achieve a cure for ROS1-rearranged NSCLC. In this study, we clarified the initial survival mechanisms during treatment with lorlatinib, a ROS1 TKI. First, we established a patient-derived ezrin gene-ROS1-rearranged NSCLC cell line (KTOR71). Then, following proteomic analysis, we focused on yes-associated protein 1 (YAP1), which is a major mediator of the Hippo pathway, as a candidate factor involved in cell survival during early lorlatinib treatment. Yes-associated protein 1 was activated by short-term lorlatinib treatment both in vitro and in vivo. Genetic inhibition of YAP1 using siRNA, or pharmacological inhibition of YAP1 function by the YAP1-inhibitor verteporfin, enhanced the sensitivity of KTOR71 cells to lorlatinib. In addition, the prosurvival effect of YAP1 was exerted through the reactivation of AKT. Finally, combined therapy with verteporfin and lorlatinib was found to achieve significantly sustained tumor remission compared with lorlatinib monotherapy in vivo. These results suggest that YAP1 could mediate initial cell resistance to lorlatinib in KTOR71 cells. Thus, combined therapy targeting both YAP1 and ROS1 could potentially improve the outcome of ROS1-rearranged NSCLC.

Background We previously reported that PD-L1 polymorphisms are associated with the efficacy and immune-related adverse events of PD-1 blockade with nivolumab. However, the association between PD-L1 polymorphisms and survival outcomes under PD-1/PD-L1 blockade is still uncertain. Here, we aimed to investigate whether PD-L1 polymorphisms are associated with survival outcomes in advanced non-small-cell lung cancer (NSCLC) patients treated with nivolumab. Methods PD-1/PD-L1 polymorphisms and survival outcomes were retrospectively analysed in two independent cohorts (133 patients treated with nivolumab and 96 patients with no treatment history of an immune checkpoint inhibitor (ICI) (the non-ICI cohort)) with advanced NSCLC. Results Among the 7 studied single-nucleotide polymorphisms, PD-L1 rs822339 and rs1411262 were associated with overall survival (OS) in patients treated with nivolumab. Patients with the A/A genotype of rs822339 had a significantly longer OS than those with A/G or G/G genotypes (not reached versus 12.0 months; hazard ratio (HR), 0.35; 95% confidence interval (CI), 0.18–0.64; p = 0.0008). A similar survival benefit with the A/A genotype was observed regardless of driver mutation status. In multivariate analysis, performance status (PS) and PD-L1 rs822339 genotype were independent prognostic factors for OS. In the non-ICI cohort, the PD-L1 rs822339 genotype did not correlate with OS (HR, 0.77; 95% CI, 0.31–1.70; p = 0.55). The T/T genotype of rs1411262 also showed a significant prolongation of OS compared to that with the C/T or C/C genotypes in patients treated with nivolumab. Conclusions PD-L1 polymorphisms are associated with favourable OS in nivolumab-treated NSCLC patients and may be useful predictive biomarkers, regardless of driver mutation status.

Immune checkpoint therapy (ICT) with nivolumab has been widely used to treat malignant pleural mesothelioma (MPM) since clinical trials confirmed its efficacy. However, only a few clinical trials have been conducted for the treatment of sarcomatoid MPM, which is a rare histological type of MPM. Additionally, clinical reports of sarcomatoid MPM are scarce. Therefore, the benefits and risks of nivolumab treatment for sarcomatoid MPM remain unclear. The present report describes the treatment of 3 cases of sarcomatoid MPM (all 3 were men) with nivolumab monotherapy. In all three cases, nivolumab was effective despite variations in the duration of treatment, although side effects were observed in 2 patients. Programmed death ligand 1 (PD-L1) expression was positive in all 3 cases. In particular, the patient with the highest PD-L1 expression had the most rapid response of the 3 patients, and the effect lasted as long as those of the other 2, despite receiving the smallest number of doses of nivolumab. It has been reported that sarcomatoid MPM tends to respond poorly to chemotherapy and express higher levels of PD-L1 than epithelial MPM; thus, ICT may be necessary in these cases. This case series suggests that ICT with nivolumab is a promising treatment option for sarcomatoid MPM.

Nivolumab, a programmed death 1 blockade drug, is used in various types of cancers and can cause a unique immune-related adverse event (irAE). Relapsing polychondritis (RP) is a rare autoimmune disease that mainly involves inflammation of the auricle, nose and airway cartilage. A 72-year-old man with mandibular cancer received nivolumab after surgery for the primary lesion and radiation therapy for lung metastases. He then developed radiation pneumonitis, and prednisolone (PSL) was started. During the tapering of PSL, he developed exertional dyspnea and cough. The condition of mandibular cancer and radiation pneumonitis had not deteriorated. Fluorodeoxyglucose (FDG)-PET/CT showed a thickening of and abnormal FDG uptake in the tracheobronchial and nasal septum cartilage. These characteristic findings were not observed before nivolumab was initiated; thus, we clinically diagnosed the patient as having RP induced by nivolumab. Since the symptoms were mild, the patient's condition was carefully managed with inhaled corticosteroids, and the RP has not progressed thus far. Physicians should be aware that RP can occur as an irAE because RP may progress to serious respiratory symptoms.

Background Detailed differences in clinical information between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pneumonia (CP), which is the main phenotype of SARS-CoV-2 disease, and influenza pneumonia (IP) are still unclear. Methods A prospective, multicenter cohort study was conducted by including patients with CP who were hospitalized between January and June 2020 and a retrospective cohort of patients with IP hospitalized from 2009 to 2020. We compared the clinical presentations and studied the prognostic factors of CP and IP. Results Compared with the IP group (n = 66), in the multivariate analysis, the CP group (n = 362) had a lower percentage of patients with underlying asthma or chronic obstructive pulmonary disease (P < .01), lower neutrophil-to-lymphocyte ratio (P < .01), lower systolic blood pressure (P < .01), higher diastolic blood pressure (P < .01), lower aspartate aminotransferase level (P < .05), higher serum sodium level (P < .05), and more frequent multilobar infiltrates (P < .05). The diagnostic scoring system based on these findings showed excellent differentiation between CP and IP (area under the receiver operating characteristic curve, 0.889). Moreover, the prognostic predictors were different between CP and IP. Conclusions Comprehensive differences between CP and IP were revealed, highlighting the need for early differentiation between these 2 pneumonias in clinical settings.

Overcoming the treatment resistance of cancer is a problem to be solved in improving the prognosis of cancer patients. Recently, genome analysis has revealed that multiple clusters exist in one tumor, and it has been reported that intratumor heterogeneity causes treatment resistance even in lung cancer. However, the mechanism of intratumor heterogeneity has not yet been clarified. Previous studies of intratumor heterogeneity have mainly focused on analyzing cancer cells from patients, classifying clusters of different properties, and identifying factors that define their characteristics. Multiple clusters are present in the tumor tissue of a single patient, and analysis of multiple patients classifies them into even more clusters, but it is difficult to research all of them. To solve this problem, an early model of intratumor heterogeneity in which homogeneous cells become heterogeneous is needed.We hypothesized that intratumor heterogeneity cell model could be found in resistant strains.Alectinib was exposed in vitro to an ALK-positive lung cancer cell line (H2228) to create an alectinib-resistant cell line (H2228-AR1S). H2228-AR1S has two subpopulations that look different. Of the two subpopulations, the smaller cells have high CD47 expression (CD47 high subpopulation), and the scattered spindle-shaped cells have low CD47 expression (CD47 low subpopulation). Using flow cytometry, each subpopulation was isolated, and its properties were investigated. There was no difference in sensitivity to alectinib between the CD47 high subpopulation and the CD47 low subpopulation. In the low subpopulation of CD47, epithelial markers were decreased, and mesenchymal markers were increased using immunoblotting. It suggests that CD47 low subpopulation has undergone epithelial-mesenchymal transition (EMT). The CD47 high subpopulation had high sphere formation ability in vitro, and high tumorigenicity using Xenograft model. CD47 gene inhibition using siRNA reduced the sphere formation ability of the CD47 high subpopulation. This suggests that CD47 is involved in sphere formation.There have been no reports of CD47 being involved in the characteristics of intratumor heterogeneity. Furthermore, using intratumor heterogeneity cell model, we are exploring the mechanism that regulate division into two subpopulations. Citation Format: Tomoko Y. Funazo, Hiroaki Ozasa, Kentaro Hashimoto, Hiroshi Yoshida, Tatsuya Ogimoto, Kazutaka Hosoya, Hitomi Ajimizu, Takahiro Tsuji, Hironori Yoshida, Ryo Itotani, Yuichi Sakamori, Toyohiro Hirai. CD47 related to intratumor heterogeneity in alectinib-resistant ALK-rearranged lung cancer cell lines [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 1601.

Background: EGFR mutation-positive lung cancer has high response rates to EGFR-tyrosine kinase inhibitors (TKIs), but eventually acquires resistance to EGFR-TKIs. Acquired resistance mechanisms are diverse because of tumor heterogeneity, which makes it difficult to overcome acquired resistance. Initial resistance is the resistance mechanism of tumor cells that survive the initial treatment. If we could overcome the initial resistance, we could prevent cancer cells from developing various types of acquired resistance. We are now focusing on YAP1 and cancer stem cells, which have been also reported as acquired resistance mechanisms in various types of cancers. Methods: PC-9 cells and HCC827 cells which were EGFR mutation-positive lung cancer cell lines were mainly utilized in our experiments; they were purchased from ECACC and ATCC, respectively. We mainly utilized osimertinib as an EGFR-TKI and verteporfin as a YAP1 inhibitor. The nuclear translocation of YAP1 was confirmed by fluorescence immunostaining. siRNA was utilized to knock down YAP1. Cell viability assays were performed using CellTiter-Glo reagent. qRT-PCR was performed to confirm the gene expression of cancer stem cells. Results: YAP1 is activated by nuclear translocation. In PC-9 cells, YAP1 was localized in the nucleus after osimertinib exposure. In contrast, YAP1 was localized in the nucleus of HCC827 cells before osimertinib exposure and remained in the nucleus even after osimertinib exposure. These data suggest that YAP1 activation is correlated with initial resistance. Cell viability assay showed that both PC-9 cells and HCC827 cells became more sensitive to osimertinib with the knocking down of YAP1. In addition, cell viability assays using PC-9 cells with verteporfin and osimertinib showed increased sensitivity to osimertinib. The gene expression of ALDH1A1 and SOX2 which are involved in cancer stem cells were increased in PC-9 cells after osimertinib exposure. On the other hand, the gene expression of ALDH1A1 was up-regulated but SOX2 was down-regulated in HCC827 cells after osimertinib exposure. We hypothesized that increased gene expression of cancer stem cells occurred downstream of YAP1 followed by initial resistance, thus we are currently confirming the gene alteration of cancer stem cells associated with osimertinib exposure with the knocking down YAP1. We are also considering the investigation of combination therapy of EGFR-TKIs and YAP1 inhibitors in vivo studies. Conclusions: YAP1 and cancer stem cells may be involved in initial resistance mechanisms to EGFR-TKIs in EGFR mutation-positive lung cancer. Our results suggest that especially YAP1 can be a potential therapeutic target, thus we will continue additional studies of combination therapy of EGFR-TKIs and YAP1 inhibitors. In addition, we will continue to investigate whether the gene for cancer stem cells acts downstream of YAP1. Citation Format: Tatsuya Ogimoto, Hiroaki Ozasa, Kentaro Hashimoto, Hiroshi Yoshida, Kazutaka Hosoya, Masatoshi Yamazoe, Hitomi Ajimizu, Tomoko Funazo, Takahiro Tsuji, Hironori Yoshida, Ryo Itotani, Yuichi Sakamori, Toyohiro Hirai. Elucidation of initial resistance mechanisms in EGFR mutation-positive lung cancer focusing on YAP1 and cancer stem cells [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 5335.

Regarding bowing in Japan, the bowing technique of students was compared with the bowing of adults. The bowing data of the students was analyzed. The subjects were junior high school first year and second years students (N = 12). For the measurement, three infrared cameras and TEMA, a high-performance moving image analysis software, was used. In the experiment, motion capture observation points were attached to the head, neck, waist and ankle of the subject. The recorded data was analyzed with TEMA, and the numerical values for six points of body movement were calculated. Moreover a questionnaire was conducted to survey students about their impressions of bowing. By comparing the bowing of adults and students, the following points were identified. First, it was observed that the variance in bowing between students differs greatly. The second observation is the difference in angle of the neck. The third observation is the difference in angle of the waist. The fourth observation is the difference in awareness of bowing. Through this study, it is demonstrated that there are many differences between the bowing of students and adults. Also, it was found that there are many differences between subjects.