Takayuki Takimoto

Polymorphisms of CYP2D6 gene and gefitinib-induced hepatotoxicity.

INTRODUCTION Gefitinib induces severe hepatotoxicity in approximately a quarter of Japanese patients with epidermal growth factor receptor (EGFR) mutation-positive non-small-cell lung cancer (NSCLC). Gefitinib is metabolized by cytochrome P450 (CYP) enzymes--including CYP3A4/5, CYP1A1, and CYP2D6--in the liver. We hypothesized that polymorphisms of the CYP2D6 gene may account for gefitinib-induced hepatotoxicity. PATIENTS AND METHODS Polymorphisms of the CYP2D6 gene were analyzed in 55 patients with NSCLC who experienced grade ≥ 2 transaminase elevation from gefitinib. The distribution of the CYP2D6 genotype was compared with that of the healthy Japanese population. The correlations between the nonfunctional allele *5 or the reduced-function allele *10 and hepatotoxicity-related clinical factors were also examined. RESULTS The distribution of the CYP2D6 genotype in the study participants was not different from that of the general Japanese population, reported previously. Existence of allele *5 or *10 did not correlate with clinical factors such as onset of hepatotoxicity within 2 months, grade ≥ 3 serum transaminase elevation, and tolerability to dose reduction or rechallenge of gefitinib. However, in 7 patients taking CYP3A4-inhibitory drugs, rechallenge of gefitinib again caused hepatotoxicity in 4 patients with allele *5 or *10 but not in 3 patients with normal alleles (P = .029). Moreover, switching to erlotinib did not cause hepatotoxicity in any of 17 patients with allele *5 or *10 but did in 3 of 8 patients without these alleles (P = .024). CONCLUSION Reduced function of CYP2D6 may partly account for gefitinib-induced hepatotoxicity when CYP3A4 is inhibited. Erlotinib could be safely used in patients with decreased CYP2D6 activity even after they experienced gefitinib-induced hepatotoxicity.

Lethal Adenovirus Infection in a Patient Who Had Undergone Nonmyeloablative Stem Cell Transplantation

We present a case of adenovirus (ADV) infection in a patient who had undergone nonmyeloablative stem cell transplantation (NST). A 50-year-old man with chronic myelogenous leukemia in the second chronic phase underwent NST from an HLA 2-loci-mismatched sibling.ADV hemorrhagic cystitis developed and progressed to lethal pneumonia.ADV was isolated from urine, bronchoalveolar lavage fluid, and postmortem specimens of kidney and liver. Because there are few reports of lethal pneumonia associated with ADV in Japan, we present the case and discuss the cause of and therapy for the infection.

Tubular nephrotoxicity induced by docetaxel in non-small-cell lung cancer patients

Renal dysfunction is a characteristic of many patients with cancer; however, a standard therapy has not been established for stage III or IV non-small-cell lung cancer (NSCLC) complicated with chronic renal failure. Docetaxel has a proven significant activity against NSCLC. This agent is predominantly eliminated by hepatobiliary extraction and is safe in patients with renal failure, including dialysis patients. Docetaxel is, thus, a therapeutic option in that patient population. Here, we report acute tubular nephrotoxicity secondary to docetaxel in NSCLC patients, even in patients with normal renal function. Little is known about tubular nephrotoxicity induced by docetaxel; however, oncologists should be aware of its possibility.

Primary Pulmonary T-Cell Lymphoma in a Human T-Lymphotropic Virus Type-1 Carrier Showing Atypical Shadow

A 68-year-old man was admitted to our hospital for cough and dyspnea. Laboratory data showed positive human T-lymphotropic virus type 1 (HTLV-1) antibody and elevated level of soluble interleukin-2 receptor (4225 U/ml). Thoracic computed tomography showed emphysema, reticular shadow, ground-glass attenuation, and subpleural consolidation (Figure 1). Bronchofiberscopy was carried out and cytologic examination of bronchoalveolar lavage fluid revealed atypical lymphocytes. These cells showed positive reaction for CD2, CD3, CD4, CD5, and CD25 and negative for CD8 in flow cytometry. Specimens of transbronchial lung biopsy showed massive infiltration of malignant lymphocytes, which were

4-Hydroxy-2-nonenal induces chronic obstructive pulmonary disease-like histopathologic changes in mice

The α,β-unsaturated aldehyde 4-hydroxy-2-nonenal (4-HNE) is an endogenous product of oxidative stress that is found at increased levels in the lungs of patients with chronic obstructive pulmonary disease (COPD) and animal models of this lung disorder. In the present study, levels of 4-HNE adducts were increased in two different mouse models of COPD. Challenging lungs with 4-HNE enlarged the airspace and induced goblet cell metaplasia of the airways in mice, two characteristics of COPD. 4-HNE induced the accumulation of inflammatory cells expressing high levels of MMP-2 and MMP-9. Our results indicate that 4-HNE production during oxidative stress is a key pathway in the pathogenesis of COPD.

Rapid intracranial response to osimertinib, without radiotherapy, in nonsmall cell lung cancer patients harboring the EGFR T790M mutation: Two Case Reports

Rationale: Most of nonsmall cell lung cancer (NSCLC) patients harboring epidermal growth factor receptor (EGFR) activating mutations eventually acquire resistance to the first EGFR-tyrosine kinase inhibitors (TKIs) therapy after varying periods of treatment. Of note, approximately one-third of those patients develop brain metastases, which deteriorate their quality of life and survival. The effect of systemic chemotherapy on brain metastases after acquisition of EGFR-TKI resistance is limited, and thus far, whole-brain radiation therapy, which may cause the harmful effect on neurocognitive functions, has been the only established therapeutic option for especially symptomatic brain metastases. Osimertinib is a third-generation oral, potent, and irreversible EGFR-TKI. It can bind to EGFRs with high affinity even when the EGFR T790M mutation exists in addition to the sensitizing mutations. Its clinical efficacy for NSCLC patients harboring the T790M mutation has already been shown; however, the evidence of osimertinib on brain metastases has not been documented well, especially in terms of the appropriate timing for treatment and its response evaluation. Patient concerns, Diagnoses, and Interventions: We experienced 2 NSCLC patients with the EGFR T790M mutation; a 67-year-old woman with symptomatic multiple brain metastases administered osimertinib as seventh-line chemotherapy, and a 76-year old man with an asymptomatic single brain metastasis administered osimertinib as fifth-line chemotherapy. Outcomes: These patients showed great response to osimertinib within 2 weeks without radiation therapy. Lessons: These are the first reports to reveal the rapid response of the brain metastases to osimertinib within 2 weeks. These cases suggest the possibility that preemptive administration of osimertinib may help patients to postpone or avoid radiation exposures. In addition, rapid reassessment of the effect of osimertinib on brain metastases could prevent patients from being too late to receive essential radiotherapy.

Preliminary experience with a modified premedication protocol that included intravenous diphenhydramine and calcium bromide for the prophylaxis of paclitaxel-related hypersensitivity reactions.

BackgroundPaclitaxel often causes severe hypersensitivity reactions (HSRs) rapidly after infusion, even in patients given prophylactic therapy. The purpose of this study was to analyze the incidence of paclitaxel-related HSRs in patients with non-small cell lung cancer (NSCLC) retrospectively, and to assess the feasibility of a modified premedication protocol.MethodsOne hundred and seven patients who were pretreated with either a conventional premedication regimen (two doses of dexamethasone) or a short premedication regimen (single dose of dexamethasone with oral diphenhydramine and intravenous ranitidine), prior to paclitaxel infusion were retrospectively analyzed. A modified premedication regimen, consisting of 12.5 ml of Rescalmin (intravenous diphenhydramine 50 mg and calcium bromide 437.5 mg), intravenous ranitidine 100 mg, and intravenous dexamethasone 20 mg, was given 30 min prior to paclitaxel, with oral dexamethasone 8 mg given on the night before the paclitaxel. Patients received paclitaxel intravenously at 175 mg/m2 over 3 h, followed by carboplatin, AUC 5, over 1 h on day 1 every 3 weeks.ResultsIn the conventional premedication group, 21 patients had HSRs (32.3%); in 1 of these patients the HSR was considered to be severe (1.5%). In the short premedication group, 19 patients had HSRs (45.2%); in 6 of these patients the HSRs were considered to be severe (14.3%). The incidence of severe HSRs was significantly higher in the short premedication group than in the conventional premedication group (P = 0.027). In the modified premedication protocol study, HSR events were recorded in 14 patients (63.6%); 14 showed flushing, 2 had skin rash, and 1 had tachycardia. No severe HSRs were seen.ConclusionsThe incidence of HSRs in the short premedication group tended to be higher than that in the conventional premedication group. The modified premedication protocol was found to be feasible for preventing paclitaxel-related HSR, but case accumulation is needed.

4-Hydroxy-2-nonenal induces endothelial cell injury via PKCdelta and biphasic JNK activation

Hydroxy-2-nonenal (4-HNE), a major product generated during oxidative stress, exhibits cytotoxic effects; however, the mechanisms of 4-HNE-induced endothelial cell injury are not well defined. To explore this issue, we examined how 4-HNE damages human umbilical vein endothelial cells (HUVECs) and found that 4-HNE induced biphasic activation of c-Jun N-terminal kinase (JNK). Both pre- and post-treatment of HUVECs with SP600125, a spe- cific JNK inhibitor, significantly suppressed the cytotoxic effects of 4-HNE. Inhibition of protein kinase Cδ (PKCδ), which was also phosphorylated by 4-HNE, reduced endothelial cell injury as well as late-phase JNK phosphorylation elicited by 4-HNE. Inversely, pre-treatment of HUVECs with SP600125 suppressed PKCδ activation. Taken together, these results support the concept that 4-HNE induces vascular endothelial cell injury by the interac- tion between biphasic JNK activation and the PKCδ pathway.

Clarifying the biological significance of the CHK2 K373E somatic mutation discovered in The Cancer Genome Atlas database

We identified CHK2 K373E as a recurrent mutation in The Cancer Genome Atlas (TCGA) database. In this study, we demonstrate that the K373E mutation disrupts CHK2 autophosphorylation as well as kinase activity, thus leading to impairment of CHK2 functions in suppressing cell proliferation and promoting cell survival after ionizing radiation. We propose that K373E impairs p53‐independent induction of p21WAF1/CIP1 by CHK2. Our data implicate the K373E mutation of CHK2 in tumorigenesis.

Double deletion of tetraspanins CD9 and CD81 in mice leads to a syndrome resembling accelerated aging

Chronic obstructive pulmonary disease (COPD) has been recently characterized as a disease of accelerated lung aging, but the mechanism remains unclear. Tetraspanins have emerged as key players in malignancy and inflammatory diseases. Here, we found that CD9/CD81 double knockout (DKO) mice with a COPD-like phenotype progressively developed a syndrome resembling human aging, including cataracts, hair loss, and atrophy of various organs, including thymus, muscle, and testis, resulting in shorter survival than wild-type (WT) mice. Consistent with this, DNA microarray analysis of DKO mouse lungs revealed differential expression of genes involved in cell death, inflammation, and the sirtuin-1 (SIRT1) pathway. Accordingly, expression of SIRT1 was reduced in DKO mouse lungs. Importantly, siRNA knockdown of CD9 and CD81 in lung epithelial cells additively decreased SIRT1 and Foxo3a expression, but reciprocally upregulated the expression of p21 and p53, leading to reduced cell proliferation and elevated apoptosis. Furthermore, deletion of these tetraspanins increased the expression of pro-inflammatory genes and IL-8. Hence, CD9 and CD81 might coordinately prevent senescence and inflammation, partly by maintaining SIRT1 expression. Altogether, CD9/CD81 DKO mice represent a novel model for both COPD and accelerated senescence.