Koichi Saruwatari

Signaling through the Phosphatidylinositol 3-Kinase (PI3K)/Mammalian Target of Rapamycin (mTOR) Axis Is Responsible for Aerobic Glycolysis mediated by Glucose Transporter in Epidermal Growth Factor Receptor (EGFR)-mutated Lung Adenocarcinoma

Background: EGFR signaling maintains aerobic glycolysis, but the molecular mechanism is still undefined. Results: Drug inhibition studies reveal that downstream signaling via the PI3K pathway is critical for glucose transport and metabolism. Conclusion: The PI3K signaling regulates key metabolic activities in EGFR-mutant lung adenocarcinoma. Significance: These data may guide the development of chemotherapeutic options, including targeting of the PI3K pathway and glucose transporter machinery. Oncogenic epidermal growth factor receptor (EGFR) signaling plays an important role in regulating global metabolic pathways, including aerobic glycolysis, the pentose phosphate pathway (PPP), and pyrimidine biosynthesis. However, the molecular mechanism by which EGFR signaling regulates cancer cell metabolism is still unclear. To elucidate how EGFR signaling is linked to metabolic activity, we investigated the involvement of the RAS/MEK/ERK and PI3K/AKT/mammalian target of rapamycin (mTOR) pathways on metabolic alteration in lung adenocarcinoma (LAD) cell lines with activating EGFR mutations. Although MEK inhibition did not alter lactate production and the extracellular acidification rate, PI3K/mTOR inhibitors significantly suppressed glycolysis in EGFR-mutant LAD cells. Moreover, a comprehensive metabolomics analysis revealed that the levels of glucose 6-phosphate and 6-phosphogluconate as early metabolites in glycolysis and PPP were decreased after inhibition of the PI3K/AKT/mTOR pathway, suggesting a link between PI3K signaling and the proper function of glucose transporters or hexokinases in glycolysis. Indeed, PI3K/mTOR inhibition effectively suppressed membrane localization of facilitative glucose transporter 1 (GLUT1), which, instead, accumulated in the cytoplasm. Finally, aerobic glycolysis and cell proliferation were down-regulated when GLUT1 gene expression was suppressed by RNAi. Taken together, these results suggest that PI3K/AKT/mTOR signaling is indispensable for the regulation of aerobic glycolysis in EGFR-mutated LAD cells.

Aggressive tumor microenvironment of solid predominant lung adenocarcinoma subtype harboring with epidermal growth factor receptor mutations

INTRODUCTION Tumor microenvironment critically affects cancer progression. This study aimed to identify differences in microenvironments of lung adenocarcinomas with epidermal growth factor receptor (EGFR) mutations by histological subtypes. METHODS The study cohort included 214 lung adenocarcinomas harboring EGFR mutations. We analyzed clinicopathological characteristics of lepidic (LPA), papillary (PPA), acinar (APA), and solid-predominant adenocarcinoma (SPA) subtypes, and examined expression levels of EGFR, E-cadherin, ezrin, laminin-5, ALDH1, and PD-L1 in cancer cells, and of CD34, CD204, podoplanin (PDPN), and FoxP3 in stromal cells in 4 subtypes (n=20 each). RESULTS SPA displayed significantly more frequent lymph node metastasis, lymphovascular invasion, and worse prognosis than the other subtypes. Ezrin expression levels in SPA were also significantly higher than in LPA, PPA, or APA (P<0.05, all). Laminin-5 and PD-L1 expression levels in SPA were significantly higher than in LPA (P<0.01 for both) and PPA (P<0.01 for both) and tended to be higher than in APA (laminin-5: P=0.096, PD-L1: P=0.081). Furthermore, SPA displayed higher levels of PDPN (+) cancer-associated fibroblasts (P<0.01) and CD204 (+) tumor-associated macrophages (P<0.05) than the other subtypes. CONCLUSION Compared with other predominant subtypes with EGFR mutations, the microenvironment of SPA with EGFR mutations is characterized by cancer cells with higher invasive and immune evasion potential and more abundant stromal cells with tumor-promoting functions, which would contribute to the more aggressive behavior of SPA.

Dose escalation and pharmacokinetic study of carboplatin plus pemetrexed for elderly patients with advanced nonsquamous non-small-cell lung cancer: Kumamoto thoracic oncology study group trial 1002

Objectives: This study was designed to determine the recommended dose of carboplatin and pemetrexed for elderly (≥70-year-old) chemotherapy-naïve patients with advanced nonsquamous non-small-cell lung cancer (NSCLC) and to investigate the pharmacokinetics of pemetrexed. Methods: The patients were treated with 4-6 cycles of carboplatin plus a fixed dose of pemetrexed (500 mg/m2) every 3 weeks; the dose of carboplatin was escalated [from area under the curve (AUC) 4 to AUC 6]. To examine the pharmacokinetics of pemetrexed, blood samples were collected before and after pemetrexed infusion, and the blood levels of pemetrexed were measured by liquid chromatography-mass spectrometry. Results: Grade 3 infection as a dose-limiting toxicity was observed at a carboplatin dose of AUC 6. We therefore determined a carboplatin dose of AUC 5 and a pemetrexed dose of 500 mg/m2 as the recommended doses from this study. The pharmacokinetic study showed a significant inverse correlation between the AUC of pemetrexed and the creatinine clearance. Conclusions: For elderly chemotherapy-naïve patients with advanced nonsquamous NSCLC, the combination of carboplatin AUC 5 plus pemetrexed 500 mg/m2 is recommended as a promising regimen; however, a reduction of the pemetrexed dose may be required for patients with renal dysfunction because of the high risk of hematotoxicities.

Immunohistochemical and genetic characteristics of lung cancer mimicking organizing pneumonia

INTRODUCTION Lung cancer mimicking organizing pneumonia (LCOP) is a novel radiological entity of lung adenocarcinoma that could be misdiagnosed as inflammatory lesions. However, the characteristic biological and genetic features of LCOP are not fully clarified. MATERIALS AND METHODS We used thin-section CT images to select cases of (LCOP) among surgically resected lung adenocarcinoma patients. We compared the clinicopathological characteristics and the immunophenotypes of LCOP (n=44) and other lepidic-predominant adenocarcinomas (non-LCOP, n=56). We also analyzed the genomic mutation features of LCOP (n=4) by whole-exome sequencing (WES). RESULTS All LCOP lesions were lepidic-predominant invasive adenocarcinoma. Patients with LCOP had significantly superior recurrence-free survival, compared to non-LCOP patients (95.5% and 74.4%; P=0.006, respectively). Vascular invasion and lymph node metastasis were less frequent in LCOP than in non-LCOP patients (P=0.001 and P=0.03, respectively). The cancer cell expression levels of aggressiveness-related molecules, including ezrin, ALDH-1, laminin-5 were similar between LCOP and non-LCOP. On the contrary, the number of tumor promoting stromal cells, i.e., podoplanin-positive cancer-associated fibroblasts and CD204-positive tumor associated macrophages, was significantly lower in LOCP (P=0.021 and P=0.037, respectively). WES revealed that ABCB1, DNAH3, MSI2, and SLITRK2 were specifically mutated in LCOP. CONCLUSIONS Our results indicate that LCOP is characterized by fewer tumor-promoting stromal cells, which may contribute to the better prognosis of LCOP patients. Moreover, recognition of specific somatic mutations of LCOP patients may provide information regarding the development and progression of this type of lung cancer.

Trousseau's syndrome triggered by an immune checkpoint blockade in a non-small cell lung cancer patient

PD-1 blockade therapy activates T cells by blocking the interaction between PD-1 and PD-L1 and promotes IFN-γ and Th1 cytokine production. In turn, IFN-γ and Th1 cytokines produced by activated T cells promote TF synthesis in monocytes/macrophages, which results in hypercoagulability leading to thrombosis.

O1-4-4Association of the bevacizumab pharmacokinetics with efficacy and toxicity in advanced non-small cell lung cancer

lung, and it was significantly associated with shorter survival rate after curative surgery. In addition, URST1 was expressed in 64 of 96 (66.7%) oral cancers, but not in oral mucosa, and it was significantly correlated with poor prognosis after surgery. Multivariate analysis confirmed that URST1 expression was an independent prognostic factor for oral cancer. Suppression of URST1 expression by siRNA or treatment with synthesized inhibitor specific for URST1 activity inhibited mitosis and growth of lung or oral cancer cell lines. Our results suggest that URST1 could be a prognostic biomarker and therapeutic target for aerodigestive cancers such as lung or oral cancers.