Potential of fluoropyrimidine to be an immunologically optimal partner of immune checkpoint inhibitors through inducing immunogenic cell death for thoracic malignancies.

BACKGROUND: Immune checkpoint inhibitors (ICIs) are a revolutionary paradigm in the treatment of thoracic malignancies and chemoimmunotherapy is a current standard care in this field. Chemotherapeutic agents are known to induce not only direct cytotoxic effects on tumor cells but also immune modulating effects, such as stimulating immunogenic cell death (ICD). Currently, either pemetrexed (PEM) or taxane plus platinum are combined with ICIs for patients with non-small cell lung cancer (NSCLC); however, it is still unknown whether these agents are immunologically optimal partners for ICIs. METHODS: To determine the immunologically optimal chemotherapeutic agent, we first evaluated the ability of several chemotherapeutic agents, including platinum, PEM, taxane, and 5-fluorouracil (5-FU) to induce ICD using several thoracic tumor cell lines in vitro. ICD was evaluated by the cell surface expression of calreticulin (CRT) and adenosine-triphosphate (ATP) secretion. We further performed an antitumor vaccination assay in vivo. RESULTS: 5-FU induced cell surface expression of CRT and ATP secretion most efficiently among the several chemotherapeutic agents. This effect was enhanced when it was combined with platinum. In the antitumor vaccination assay in vivo, we found that vaccination with dying-AB1-HA (a murine malignant mesothelioma cell line) cells treated with 5-FU, but neither PEM nor PTX, reduced the tumor growth of living-AB1-HA cells inoculated 1 week after vaccination by recruiting CD3+ CD8+ T cells into the tumor microenvironment. CONCLUSION: Our findings indicate that fluoropyrimidine can be an immunologically optimal partner of ICIs through the induction of ICD for thoracic malignancies.

Risk Factors Related to Severity in COVID-19 Patients: A Real-world Retrospective Cohort Study.

Objective Understanding the clinical factors associated with the severity of coronavirus disease 2019 (COVID-19) is very important for the effective use of limited medical resources, including the appropriate evaluation of the need for hospitalization and discharge. Methods Patients hospitalized with a diagnosis of COVID-19 from March 2021 to October 2022 were included in the study. Patients admitted to our facility were classified into four waves: 4th (April to June 2021), 5th (July to October 2021), 6th (January to June 2022), and 7th waves (July to October 2022). We analyzed the severity, patients' background characteristics, presence of pneumonia on chest computed tomography (CT), and blood test results in each wave. Patients were further classified into respiratory failure and nonrespiratory failure groups and statistically compared. Results Of the 565 patients diagnosed with COVID-19, 546 were included in this study. The percentage of patients classified as mild was approximately 10% in the 4th and 5th waves, but the rate increased after the 6th wave, with rates of 55.7% and 54.8% in each wave. Although more than 80% of patients in the 4th and 5th waves showed pneumonia on chest CT, the percentage decreased to approximately 40% after the 6th wave. Further comparisons between the respiratory failure group (n=75) and the nonrespiratory failure group (n=471) revealed significant differences in the age, sex, vaccination history, and biomarker values between the two groups. Conclusion In this study, elderly men were found to be more likely to develop severe disease than others, and biomarkers of COVID-19, such as C-reactive protein and lactate dehydrogenase, were useful for predicting severity. This study also suggested that vaccination may have contributed to a reduced disease severity.

S-1 eliminates MDSCs and enhances the efficacy of PD-1 blockade via regulation of tumor-derived Bv8 and S100A8 in thoracic tumor.

Myeloid-derived suppressor cells (MDSCs) have been known to play a pivotal role in the induction of immune tolerance, which limits the benefits of immune checkpoint inhibitors (ICIs). Recent studies revealed that several chemotherapeutic agents decreased tumor-infiltrating MDSCs. Therefore, combination therapy with cytotoxic chemotherapeutic agents and ICIs was approved for first-line treatment for lung cancer. However, the impact of chemotherapeutic agents on MDSCs and an optimal partner of ICIs has not been fully investigated in thoracic tumors, including lung cancer and malignant pleural mesothelioma. In the present study, we found that treatment with 5-FU and its oral formulation, S-1, suppressed tumor progression and inhibited the accumulation of MDSCs in thoracic tumor-bearing mice. Tumor-infiltrating T cells and dendritic cells were significantly expanded in S-1-treated mice. 5-FU suppressed the ability of tumor cells to recruit MDSCs, while it did not suppress the survival and differentiation of mouse MDSCs in vitro. We also revealed that 5-FU or S-1 significantly downregulated the expression of tumor-derived Bv8 and S100A8. The knockdown of Bv8 or S100A8 in tumor cells suppressed tumor growth and MDSC recruitment in vivo. Furthermore, in comparison with pemetrexed, administration of S-1 improved the synergistic therapeutic efficacy of anti-PD-1 antibodies with or without carboplatin. Our findings revealed a novel mechanism wherein S-1 primed a favorable tumor microenvironment to provide the rationale for combination therapy with S-1 and ICIs as the optimal therapy for thoracic cancer.

Anti-PD-1 antibody combined with chemotherapy suppresses the growth of mesothelioma by reducing myeloid-derived suppressor cells.

BACKGROUND: The combination of anti-PD-1/PD-L1 antibody with chemotherapy has been approved for the first-line therapy of lung cancer. However, the effects against malignant mesothelioma (MPM) and the immunological mechanisms by which chemotherapy enhances the effect of targeting PD-1/PD-L1 in MPM are poorly understood. MATERIALS AND METHODS: We utilized syngeneic mouse models of MPM and lung cancer and assessed the therapeutic effects of anti-PD-1 antibody and its combination with cisplatin (CDDP) and pemetrexed (PEM). An immunological analysis of tumor-infiltrating cells was performed with immunohistochemistry. RESULTS: We observed significant therapeutic effects of anti-PD-1 antibody against MPM. Although the effect was associated with CD8+ and CD4+ T cells in tumors, the number of Foxp3+ cells was not reduced but rather increased. Consequently, combination with CDDP/PEM significantly enhanced the antitumor effects of anti-PD-1 antibody by decreasing numbers of intratumoral myeloid-derived suppressor cells (MDSCs) and vessels probably through suppression of VEGF expression by CDDP + PEM. CONCLUSIONS: The combination of anti-PD-1 antibody with CDDP + PEM may be a promising therapy for MPM via inhibiting the accumulation of MDSCs and vessels in tumors.

Development, validation, and comparison of gene analysis methods for detecting EGFR mutation from non-small cell lung cancer patients-derived circulating free DNA.

The feasibility and required sensitivity of circulating free DNA (cfDNA)-based detection methods in second-line epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) treatment are not well elucidated. We examined T790M and other activating mutations of EGFR by cfDNA to assess the clinical usability. In 45 non-small cell lung cancer (NSCLC) patients harboring activating EGFR mutations, cfDNAs were prepared from the plasma samples. EGFR mutations in cfDNA were detected using highly sensitive methods and originally developed assays and these results were compared to tissue-based definitive diagnoses. The specificity of each cfDNA-based method ranged 96-100% whereas the sensitivity ranged 56-67%, indicating its low pseudo-positive rate. In EGFR-TKI failure cohort, 41-46% samples were positive for T790M by each cfDNA-based method, which was comparable to re-biopsy tissue-based T790M positive rates in literature. The concordance of the results for each EGFR mutation ranged from 83-95%. In eight patients, the results of the cfDNA-based assays and re-biopsy-derived tissue-based test were compared. The observed overall agreement ranged in 50-63% in T790M, and in 63-100% in activating EGFR mutations. In this study, we have newly developed three types of assay which have enough sensitivity to detect cfDNA. We also detected T790M in 44% of patients who failed prior EGFR-TKI treatment, indicating that cfDNA-based assay has clinical relevance for detecting acquired mutations of EGFR.

A case of interstitial pneumonia associated with anti-PL-7 antibody in a patient with rheumatoid arthritis.

A 65-year-old female had been treated rheumatoid arthritis (RA), interstitial pneumonia (IP) and nephrotic syndrome with prednisolone and cyclosporine. She was emergently admitted to our hospital due to the worsening exertional dyspnea and severe hypoxemia. Chest computed tomography (CT) showed new diffuse ground-glass opacities (GGOs) with slight consolidations along with bronchovascular bundle were observed in addition to pre-existing reticular shadows in both lungs with lower lobe-predominance. An acute exacerbation (AE) of pre-existing IP triggered by an infection was suspected, and the treatment with antibiotics and corticosteroid pulse therapy improved her general condition and chest radiological findings. Because some auto-antibodies associated with acute/subacute onset IP have recently become available in clinic, we examined those including anti-aminoacyl tRNA synthetase (ARS) antibodies, and found that she was positive for anti-PL-7 antibody. We diagnosed her anti-synthetase syndrome (ASS) without symptom of myositis, and her IP was considered to be ASS-related. The careful consideration is necessary to precisely diagnose and treat the patients with RA-associated interstitial lung diseases as the several etiologies may be overlapped in the same patient. J. Med. Invest. 65:147-150, February, 2018.