Yohei Korogi

Generation of Alveolar Epithelial Spheroids via Isolated Progenitor Cells from Human Pluripotent Stem Cells

Summary No methods for isolating induced alveolar epithelial progenitor cells (AEPCs) from human embryonic stem cells (hESCs) and induced pluripotent stem cells (hiPSCs) have been reported. Based on a study of the stepwise induction of alveolar epithelial cells (AECs), we identified carboxypeptidase M (CPM) as a surface marker of NKX2-1+ “ventralized” anterior foregut endoderm cells (VAFECs) in vitro and in fetal human and murine lungs. Using SFTPC-GFP reporter hPSCs and a 3D coculture system with fetal human lung fibroblasts, we showed that CPM+ cells isolated from VAFECs differentiate into AECs, demonstrating that CPM is a marker of AEPCs. Moreover, 3D coculture differentiation of CPM+ cells formed spheroids with lamellar-body-like structures and an increased expression of surfactant proteins compared with 2D differentiation. Methods to induce and isolate AEPCs using CPM and consequently generate alveolar epithelial spheroids would aid human pulmonary disease modeling and regenerative medicine.

Directed Induction of Functional Multi-ciliated Cells in Proximal Airway Epithelial Spheroids from Human Pluripotent Stem Cells

Summary Multi-ciliated airway cells (MCACs) play a role in mucociliary clearance of the lung. However, the efficient induction of functional MCACs from human pluripotent stem cells has not yet been reported. Using carboxypeptidase M (CPM) as a surface marker of NKX2-1+-ventralized anterior foregut endoderm cells (VAFECs), we report a three-dimensional differentiation protocol for generating proximal airway epithelial progenitor cell spheroids from CPM+ VAFECs. These spheroids could be induced to generate MCACs and other airway lineage cells without alveolar epithelial cells. Furthermore, the directed induction of MCACs and of pulmonary neuroendocrine lineage cells was promoted by adding DAPT, a Notch pathway inhibitor. The induced MCACs demonstrated motile cilia with a “9 + 2” microtubule arrangement and dynein arms capable of beating and generating flow for mucociliary transport. This method is expected to be useful for future studies on human airway disease modeling and regenerative medicine.

How Sensitive Are Epidermal Growth Factor Receptor–Tyrosine Kinase Inhibitors for Squamous Cell Carcinoma of the Lung Harboring EGFR Gene–Sensitive Mutations?

Introduction: Epidermal growth factor receptor (EGFR) mutations are found mostly in adenocarcinoma, and rarely in squamous cell carcinoma (SQC). Little is known about SQC harboring EGFR mutations. Methods: Between April 2006 and October 2010, we investigated the incidence of EGFR activating mutations in SQC of the lung using the peptide nucleic acid-locked nucleic acid polymerase chain reaction clamp method. The efficacy of EGFR-tyrosine kinase inhibitors (TKIs) was retrospectively evaluated in patients with EGFR-mutated SQC. Further pathologic analyses were performed using immunohistochemistry. Results: Thirty-three of 249 patients with SQC (13.3%) had EGFR mutations, including exon 19 deletion (19 of 33 patients, 58%), L858R point mutation in exon 21 (12 of 33, 36%), and G719S point mutation in exon 18 (2 of 33, 6%). Twenty of these 33 patients received EGFR-TKI therapy, and five of these 20 responded to EGFR-TKIs with a response rate of 25.0% (95% confidence interval [CI], 8.7%–49.1%). The patients’ median progression-free survival and median overall survival were 1.4 months (95% CI, 0.7–5.8 months) and 14.6 months (95% CI, 2.9–undeterminable months), respectively. Approximately one third of the EGFR-mutated SQC patients achieved progression-free survival for longer than 6 months. Some of these patients had high carcinoembryonic antigen levels or a history of never smoking, or were positive for thyroid transcription factor-1. Conclusions: Although EGFR-TKIs seem to be generally less effective in EGFR-mutated SQC than in EGFR-mutated adenocarcinoma, some EGFR-mutated SQC patients can obtain clinical benefit from EGFR-TKIs. To better identify these patients, not only EGFR mutation status, but also clinical factors and pathologic findings should be taken into consideration.

Long-term expansion of alveolar stem cells derived from human iPS cells in organoids

The stable expansion of tissue-specific stem cells in vitro has contributed to research on several organs. Alveolar epithelial type II (AT2) cells function as tissue stem cells in the lung, but robust models for studying human AT2 cells are lacking. Here we report a method for the efficient generation and long-term expansion of alveolar organoids (AOs) harboring SFTPC+ alveolar stem cells derived from human induced pluripotent stem cells (hiPSCs). hiPSC-derived SFTPC+ cells self-renewed, with transcriptomes and morphology consistent with those of AT2 cells, and were able to differentiate into alveolar epithelial type I (AT1)-like cells. Single-cell RNA-seq of SFTPC+ cells and their progenitors demonstrated that their differentiation process and cellular heterogeneity resembled those of developing AT2 cells in vivo. AOs were applicable to drug toxicology studies recapitulating AT2-cell-specific phenotypes. Our methods can help scientists overcome the limitations of current approaches to the modeling of human alveoli and should be useful for disease modeling and regenerative medicine.

A Phase II Study of Pemetrexed in Chemotherapy-naïve Elderly Patients Aged ≥75 years with Advanced Non-squamous Non-small-cell Lung Cancer (HANSHIN Oncology Group 003)

OBJECTIVE Pemetrexed has relatively mild toxicity and possibly can be administered long term to patients with non-small-cell lung cancer. We conducted a Phase II trial to evaluate the efficacy and safety of pemetrexed in chemotherapy-naïve elderly patients with advanced non-squamous non-small-cell lung cancer. METHODS In this multicenter Phase II trial, we recruited elderly patients with non-squamous non-small-cell lung cancer. Patients with previously untreated Stage IIIB or IV non-squamous non-small-cell lung cancer, ≥75 years, Eastern Cooperative Oncology Group performance status 0-1 and adequate organ functions were eligible. Patients received pemetrexed (500 mg/m(2)) intravenously on Day 1 every 3 weeks until disease progression. The primary endpoint was objective response rate. RESULTS Forty-seven patients were enrolled from August 2009 to July 2011, and 46 patients were eligible. The median age was 79 years (range 75-91 years), 57% were males, 37% had never smoked, 87% had adenocarcinoma, 74% had Stage IV and 33% had epidermal growth factor receptor tyrosine kinase-activating mutation. The median number of cycles was 4 (1-20). The objective response rate was 13.3% (95% confidence interval; 5.1-26.8%), the disease control rate was 66.7% (95% confidence interval 51.0-80.0%), the median progression-free survival was 4.9 months (95% confidence interval 3.0-6.1 months) and the median overall survival was 18.2 months (95% confidence interval 13.2-23.5 months). One Grade 5 infection (pneumonia) was observed. CONCLUSIONS This study did not meet the primary endpoint. Pemetrexed monotherapy is not recommended in chemotherapy-naïve elderly patients aged ≥75 years with advanced non-squamous non-small-cell lung cancer.

Pneumatosis Cystoides Intestinalis After Gefitinib Therapy for Pulmonary Adenocarcinoma

An 82-year-old female with right chest pain was referred to our hospital. She was diagnosed with adenocarcinoma of the lung with pleural dissemination and bone metastases. She was treated with oral gefitinib (250 mg once daily). At first, there was no apparent adverse event except for mild diarrhea. Two months after the first administration of gefitinib, she presented with mild abdominal pain, with the computed tomography revealing extensive intramural air within the intestinal wall, extending from the duodenum to the ascending colon, without portal venous air (Figure 1). A physical examination indicated no sign of toxicity, with the condition being presumed as pneumatosis cystoides intestinalis (PCI). Gefitinib was stopped and careful monitoring with dietary restriction was done. The symptoms gradually improved by conservative therapy and a follow-up computed tomography showed no sign of intramural air. Although gefitinib was readministered, the same episode repeated three times during gefitinib therapy. PCI is a rare condition that is characterized by intramural gas in the gastrointestinal tract, and its patho-

Retrospective efficacy and safety analyses of erlotinib, pemetrexed, and docetaxel in EGFR-mutation-negative patients with previously treated advanced non-squamous non-small-cell lung cancer

OBJECTIVE Several guidelines recommend erlotinib, pemetrexed, or docetaxel for second-line chemotherapy in patients with advanced non-squamous non-small-cell lung cancer (NSCLC). The aim of this study was to retrospectively evaluate the efficacy of erlotinib, pemetrexed, and docetaxel in epidermal growth factor receptor (EGFR) mutation-negative patients with previously treated advanced non-squamous NSCLC. MATERIALS AND METHODS We analyzed the efficacy of these agents in patients with previously treated advanced non-squamous NSCLC who had EGFR wild-type tumors, performance status (PS) of 0, 1, or 2 and received erlotinib, pemetrexed, or docetaxel between December 2007 and September 2011. Variability among patient backgrounds was evaluated using propensity scores to assess comparability. The efficacy of these agents was evaluated in patient subgroups with low variability. RESULTS The propensity scores showed that the backgrounds of the groups that received second-line therapy with each agent had low variability and were adequate for comparison. Patients were divided into the PS0/1 and PS2 groups for analysis. The median progression-free survival (PFS) in patients treated with erlotinib was 2.8 months in the PS0/1 group, as compared with 1.0 month in the PS0/1/2 group and 0.90 months in the PS2 group. PFS in PS0/1 patients who received erlotinib was comparable to that in PS0/1 patients who received pemetrexed (2.5 months) or docetaxel (1.9 months). Overall survival (OS) in erlotinib-, pemetrexed-, and docetaxel-treated PS0/1 patients was 16.1, 7.4 and 10.0 months, respectively. The study had limited power to detect differences in PFS and OS because of the small sample size. CONCLUSIONS Erlotinib appears to be a useful second-line option in PS0/1 patients with EGFR mutation-negative advanced non-squamous NSCLC given its mild adverse effects. The results should be carefully interpreted because of the small sample size, limited power, and retrospective nature of the study.