Toshiro Miwa

SRT1720, a SIRT1 activator, promotes tumor cell migration, and lung metastasis of breast cancer in mice

Silent information regulator 2 (SIR2) is a highly conserved protein, the mammalian orthologue of which, SIRT1, exhibits histone deacetylase activity. SIRT1 is involved not in only longevity due to caloric restriction but in a variety of diseases such as diabetes, cardiovascular dysfunction and neurodegeneration. However, accumulating evidence shows that SIRT1 is overexpressed in various types of malignant cells, and its inhibitors suppress the growth of tumor cells. The relationship between SIRT1 and metastasis remains to be clarified. Here, we examined the effect of SRT1720, a SIRT1 activator, on lung metastasis of breast cancer cells. 4T1 breast cancer cells were subcutaneously implanted into syngeneic BALB/c mice and SRT1720 was administered alone or with an antitumor agent, cisplatin. As expected, cisplatin decreased the lung metastasis score, whereas SRT1720 increased metastasis irrespective of cisplatin. In the primary tumors, cisplatin suppressed the mRNA level of angiopoietin-like protein 4 (angptl4), a lung metastasis-promoting gene product of breast cancer, but SRT1720 reduced the effectiveness of cisplatin. The results obtained with animal experiments were in accordance with those in human cancer cells; SRT1720 significantly increased the amount of VEGF secreted from MDA-MB-231 cells. Moreover, a transendothelial cell migration assay showed that SRT1720 promotes the migration of MDA-MB-231 cells across an endothelial cell layer despite the presence of cisplatin. These findings imply that SRT1720 promotes the pulmonary metastasis of breast cancer cells and SIRT1 may be an important target for suppressing metastasis to the lung.

Sirtuin 1 activator SRT1720 suppresses inflammation in an ovalbumin-induced mouse model of asthma.

Background and objective:  In asthma, reduced histone deacetylase activity and enhanced histone acetyltransferase activity in the lungs have been reported. However, the precise function of Sirtuin 1 (Sirt1), a class III histone deacetylase, and the effect of the Sirt1 activator SRT1720 on allergic inflammation have not been fully elucidated.

Outcome and prognostic factors in patients with small cell lung cancer who receive third-line chemotherapy.

Aims and Background It is reported that about 20% of patients with small cell lung cancer (SCLC) receive third-line chemotherapy. We conducted a retrospective study to investigate the outcome and prognostic factors of patients with SCLC who receive third-line chemotherapy. Methods and Study Design The medical records of patients with SCLC who received third-line chemotherapy at our institution were reviewed. Overall survival (OS) from the initiation of third-line chemotherapy was evaluated, and the association between OS and patient characteristics was assessed by the log-rank test. Results A total of 73 patients with SCLC were treated with cytotoxic drugs between 2004 and 2012, and 19 patients received third-line chemotherapy. Median OS from initiation of third-line chemotherapy was 8.5 months. Patients with higher body mass index (BMI) (P = 0.0071), lower levels of lactate dehydrogenase (LDH) (P = 0.0036), higher levels of hemoglobin (P = 0.048), longer time to progression (TTP) from the initiation of second-line treatment (P = 0.0036), and better response to second-line treatment (P = 0.029) had longer duration of OS. Conclusions It is suggested that TTP and tumor response in second-line chemotherapy, serum levels of LDH and hemoglobin, and BMI at initiation of third-line chemotherapy could be possible prognostic factors.

Cloning, bacterial expression, and unique structure of adenosylhomocysteine hydrolase-like protein 1, or inositol 1,4,5-triphosphate receptor-binding protein from mouse kidney.

Adenosylhomocysteine hydrolase (SAHase)-like protein 1 (SAH-L), also called inositol 1,4,5-triphosphate receptor-binding protein (IRBIT) is a novel protein involved in fish embryo development and calcium release in mammalian cells through protein-protein interactions. To better understand its reaction mechanism, purified protein is indispensable. Here we describe a simple purification procedure and the unique properties of SAH-L. The cDNA was isolated from mouse kidney by RT-PCR and inserted into various pETtrade mark vectors. Escherichia coli harboring a plasmid coding for SAH-L with a C-terminal His-tag could solely produce a soluble protein. SAH-L purified through a Ni(2+) column gave M(r)s of 59,000 and 190,000 by SDS-PAGE and gel filtration, respectively, which is suggestive of a trimer, but chemical cross-linking experiments demonstrated a dimer. The incompatible M(r) values implicate an irregular structure of SAH-L. In fact, SAH-L was partially purified in a form lacking the 31 N-terminal residues, and was found to be extremely susceptible to proteases in the region around residue 70. The N-terminal polypeptide (residues 1-98) was also expressed as a soluble form and was trypsin-sensitive. Circular dichroism revealed a low alpha-helix content but not a randomly extended structure. Interestingly, SAH-L contained tightly bound NAD(+) despite showing no SAHase activity. The characterized properties of SAH-L and its N-terminal fragment present the notion that the structure of the protease-sensitive N-terminal region is relatively loose and flexible rather than compact, and which protrudes from the major SAHase-like domain. This structure is supposed to be favorable to interact with the IP(3) receptor.

Utility of creatinine/cystatin C ratio as a predictive marker for adverse effects of chemotherapy in lung cancer: A retrospective study.

Objective To determine whether the creatinine/cystatin C (Cr/CysC) ratio, which is influenced by muscle mass, can be used as a predictive marker of the adverse effects of chemotherapy. Methods This single-centre, retrospective, observational study assessed patients with lung cancer. Serum Cr and CysC levels were measured once within 1 month prior the commencement of chemotherapy. Results A total of 25 patients with lung cancer were enrolled in the study: 22 received first-line therapy; three received second-line therapy. A significant difference was noted regarding the Cr/CysC ratios between patients with nonsmall-cell lung cancer (NSCLC) and those with small-cell lung cancer (0.78 versus 0.92, respectively). A significant difference was also noted in the Cr/CysC ratios of patients with NSCLC with toxicity grades <3 and ≥3 (0.84 versus 0.70, respectively). Similar findings were observed in patients with NSCLC who received platinum-based combination therapy (toxicity grade < 3, 0.85; toxicity grade ≥3, 0.69). Conclusion The Cr/CysC ratio could serve as a useful predictive marker for chemotherapy-related adverse effects in patients with NSCLC.

Ionizing radiation suppresses FAP-1 mRNA level in A549 cells via p53 activation

Ionizing radiation (IR) is known to upregulate cell surface Fas through p53 activation in various cells. However, the signaling pathway intermediating between p53 activation and cell surface Fas upregulation remains to be elucidated. Recently, Fas‐associated phosphatase‐1 (FAP‐1) has been reported to associate with Fas and inhibit cell surface Fas expression. We evaluated the expression of FAP‐1 mRNA following IR in A549 cells. Ionizing radiation inhibited the expression of FAP‐1 mRNA. Pretreatment with p53 inhibitor pifithrin α cancelled the IR‐induced downregulation of FAP‐1 mRNA. These results suggest that IR‐induced p53 activation may upregulate cell surface Fas via the down‐modulation of FAP‐1.

Miliary brain metastasis presenting with calcification in a patient with lung cancer: a case report

IntroductionMiliary brain metastasis is an extremely rare form of brain metastasis which can present with atypical imaging findings. We report the case of a patient with miliary brain metastasis of lung cancer showing calcification in metastatic lesions.Case presentationA 68-year-old Japanese woman was diagnosed with lung adenocarcinoma. Brain computed tomography revealed multiple small calcified lesions in both cerebral hemispheres. Mutation of the epidermal growth factor receptor gene (exon 21, L858R) in lung cancer cells was detected, and treatment with gefitinib was initiated. A partial response was observed; however, the patient was readmitted to our hospital because of regrowth of the primary lesion and complaints of nausea, headache, and difficulty walking. Brain magnetic resonance imaging revealed scattered tiny nodules enhanced by gadolinium. A diagnosis of leptomeningeal carcinomatosis was made on the basis of cerebrospinal fluid cytology. The patient’s general status worsened, and she died 356 days after the day of first medical examination. Upon autopsy, the brain was found to be edematous and swollen. Lung carcinoma cells were diffusely disseminated on the meningeal surface. Metastatic foci of small nodular form, accompanied by calcifications, were also found in the brain parenchyma. We diagnosed miliary metastasis of lung carcinoma.ConclusionsTo the best of our knowledge, this is the third report of calcified miliary brain metastasis confirmed by autopsy. We describe calcified lesions that increased in size during the clinical course of nine months. Brain computed tomography findings that reveal multiple small calcified lesions in patients with malignancy should raise suspicion of miliary brain metastasis.

Lactate Dehydrogenase and Body Mass Index are Prognostic Factors in Patients with Recurrent Small Cell Lung Cancer Receiving Amrubicin

Aims and Background Amrubicin monotherapy can be an effective treatment option for patients with recurrent small cell lung cancer (SCLC). We conducted this retrospective study to investigate the prognostic factors in patients with recurrent SCLC receiving amrubicin monotherapy. Methods The associations between survival and clinical data, including the performance status, body mass index (BMI), plasma lactate dehydrogenase (LDH) level, and plasma neuron-specific enolase level, were evaluated in patients with recurrent SCLC, and a subset analysis of patients with platinum-resistant disease was conducted. Results In all, 37 patients were evaluated. The median survival from the date of initiation of amrubicin monotherapy was 9.1 months (95% confidence interval 4.7–12.0 months). Multivariate analysis using a Cox proportional hazard model identified the plasma LDH level (p = 0.049), BMI (p = 0.031), and platinum resistance (p = 0.032) as independent factors associated with survival. The same associations were also observed in the subset of patients with platinum-resistant disease. Conclusions Our findings suggest that the plasma LDH level and BMI may be useful prognostic factors in patients with SCLC receiving amrubicin monotherapy, including patients with platinum-resistant disease.

Systemic dissemination of chronic necrotizing pulmonary aspergillosis in an elderly woman without comorbidity: a case report

IntroductionChronic necrotizing pulmonary aspergillosis usually occurs in mildly immune-compromised hosts or those with underlying pulmonary disease. The radiographic pattern of chronic necrotizing pulmonary aspergillosis is typically a progressive upper lobe cavitary infiltrate with pleural thickening. We report here an atypical case of chronic necrotizing pulmonary aspergillosis mimicking lung cancer, which developed into a disseminated fatal disease in an older woman with no comorbidity.Case presentationAn 80-year-old Japanese woman was referred to our hospital for a chest roentgenogram abnormality. Repeated fiber-optic bronchoscopy could not confirm any definite diagnosis, and she refused further examinations. Considering the roentgenogram findings and her age, she was followed-up as a suspected case of lung cancer without any treatment. Then, 10 months later, she complained of visual disturbance and was admitted to our department of ophthalmology. She was diagnosed as having endophthalmitis. After treatment with corticosteroids for 20 days, she developed acute encephalitis and died four weeks later. Autopsy revealed dissemination of Aspergillus hyphae throughout her body, including her brain.ConclusionsIn older patients, even if they do not have any comorbidity, chronic necrotizing pulmonary aspergillosis should be added to the differential diagnosis of solitary pulmonary lesions in a chest roentgenogram.

Relationship between Carnitine Pharmacokinetics and Fatigue in Patients Treated with Cisplatin-Containing Chemotherapy

Background: Approximately 70% of the patients who receive chemotherapy suffer from fatigue, which lowers their quality of life and also has a negative influence on therapeutic efficacy. Previous studies have suggested a relationship between blood carnitine levels and fatigue. We conducted a prospective observational study to examine the relationship between carnitine pharmacokinetics and chemotherapy-induced fatigue in patients receiving cancer chemotherapy regimens that include cisplatin. Patients and Methods: 11 patients receiving chemotherapy including cisplatin (60-80 mg/m2) were included in the study. We performed 24-h urine collections and took blood samples on day 1 (before the initiation of chemotherapy) and days 2, 3, 4, and 8 in order to measure the carnitine concentrations in the serum and urine. These were compared with measures of self-reported fatigue. The primary endpoint was the change in self-reported fatigue subscales from baseline to day 8. Results: Urinary carnitine concentrations differed significantly on days 2 and 3 (p = 0.003). The Functional Assessment of Chronic Illness Therapy-Fatigue scale version 4A score on day 8 indicated significantly higher levels of fatigue as compared to day 1 (p = 0.013). Conclusion: This study suggests that there is an association between urinary carnitine levels and self-reported fatigue.