Oxygen-evolving photosystem II structures during S1-S2-S3 transitions.

Photosystem II (PSII) catalyses the oxidation of water through a four-step cycle of Si states (i = 0-4) at the Mn4CaO5 cluster1-3, during which an extra oxygen (O6) is incorporated at the S3 state to form a possible dioxygen4-7. Structural changes of the metal cluster and its environment during the S-state transitions have been studied on the microsecond timescale. Here we use pump-probe serial femtosecond crystallography to reveal the structural dynamics of PSII from nanoseconds to milliseconds after illumination with one flash (1F) or two flashes (2F). YZ, a tyrosine residue that connects the reaction centre P680 and the Mn4CaO5 cluster, showed structural changes on a nanosecond timescale, as did its surrounding amino acid residues and water molecules, reflecting the fast transfer of electrons and protons after flash illumination. Notably, one water molecule emerged in the vicinity of Glu189 of the D1 subunit of PSII (D1-E189), and was bound to the Ca2+ ion on a sub-microsecond timescale after 2F illumination. This water molecule disappeared later with the concomitant increase of O6, suggesting that it is the origin of O6. We also observed concerted movements of water molecules in the O1, O4 and Cl-1 channels and their surrounding amino acid residues to complete the sequence of electron transfer, proton release and substrate water delivery. These results provide crucial insights into the structural dynamics of PSII during S-state transitions as well as O-O bond formation.

Theoretical elucidation of the structure, bonding, and reactivity of the CaMn4Ox clusters in the whole Kok cycle for water oxidation embedded in the oxygen evolving center of photosystem II. New molecular and quantum insights into the mechanism of the O-O bond formation.

This paper reviews our historical developments of broken-symmetry (BS) and beyond BS methods that are applicable for theoretical investigations of metalloenzymes such as OEC in PSII. The BS hybrid DFT (HDFT) calculations starting from high-resolution (HR) XRD structure in the most stable S1 state have been performed to elucidate structure and bonding of whole possible intermediates of the CaMn4Ox cluster (1) in the Si (i = 0 ~ 4) states of the Kok cycle. The large-scale HDFT/MM computations starting from HR XRD have been performed to elucidate biomolecular system structures which are crucial for examination of possible water inlet and proton release pathways for water oxidation in OEC of PSII. DLPNO CCSD(T0) computations have been performed for elucidation of scope and reliability of relative energies among the intermediates by HDFT. These computations combined with EXAFS, XRD, XFEL, and EPR experimental results have elucidated the structure, bonding, and reactivity of the key intermediates, which are indispensable for understanding and explanation of the mechanism of water oxidation in OEC of PSII. Interplay between theory and experiments have elucidated important roles of four degrees of freedom, spin, charge, orbital, and nuclear motion for understanding and explanation of the chemical reactivity of 1 embedded in protein matrix, indicating the participations of the Ca(H2O)n ion and tyrosine(Yz)-O radical as a one-electron acceptor for the O-O bond formation. The Ca-assisted Yz-coupled O-O bond formation mechanisms for water oxidation are consistent with recent XES and very recent time-resolved SFX XFEL and FTIR results.

The Nature of the Chemical Bonds of High-Valent Transition-Metal Oxo (M=O) and Peroxo (MOO) Compounds: A Historical Perspective of the Metal Oxyl-Radical Character by the Classical to Quantum Computations.

This review article describes a historical perspective of elucidation of the nature of the chemical bonds of the high-valent transition metal oxo (M=O) and peroxo (M-O-O) compounds in chemistry and biology. The basic concepts and theoretical backgrounds of the broken-symmetry (BS) method are revisited to explain orbital symmetry conservation and orbital symmetry breaking for the theoretical characterization of four different mechanisms of chemical reactions. Beyond BS methods using the natural orbitals (UNO) of the BS solutions, such as UNO CI (CC), are also revisited for the elucidation of the scope and applicability of the BS methods. Several chemical indices have been derived as the conceptual bridges between the BS and beyond BS methods. The BS molecular orbital models have been employed to explain the metal oxyl-radical character of the M=O and M-O-O bonds, which respond to their radical reactivity. The isolobal and isospin analogy between carbonyl oxide R2C-O-O and metal peroxide LFe-O-O has been applied to understand and explain the chameleonic chemical reactivity of these compounds. The isolobal and isospin analogy among Fe=O, O=O, and O have also provided the triplet atomic oxygen (3O) model for non-heme Fe(IV)=O species with strong radical reactivity. The chameleonic reactivity of the compounds I (Cpd I) and II (Cpd II) is also explained by this analogy. The early proposals obtained by these theoretical models have been examined based on recent computational results by hybrid DFT (UHDFT), DLPNO CCSD(T0), CASPT2, and UNO CI (CC) methods and quantum computing (QC).

Five-year follow-up results from phase II studies of nivolumab in Japanese patients with previously treated advanced non-small cell lung cancer: pooled analysis of the ONO-4538-05 and ONO-4538-06 studies.

BACKGROUND: Two phase II studies in Japan examined the efficacy and safety of nivolumab, a programmed cell death 1 receptor inhibitor, in patients with advanced squamous and non-squamous non-small cell lung cancer (ONO-4538-05 and ONO-4538-06). We examined the long-term efficacy and safety of nivolumab in these patients treated for up to 5 years. METHODS: Patients with squamous (N = 35) or non-squamous (N = 76) non-small cell lung cancer received nivolumab (3 mg/kg every 2 weeks) until disease progression/death. Overall survival and progression-free survival were assessed at 5 years after starting treatment in separate and pooled analyses. Safety was evaluated in terms of treatment-related adverse events. RESULTS: A total of 17 patients were alive at the database lock (26 July 2019). The median overall survival (95% confidence interval) and 5-year survival rate were 16.3 (12.4-25.2) months and 14.3% in squamous patients, 17.1 (13.3-23.0) months and 19.4% in non-squamous patients and 17.1 (14.2-20.6) months and 17.8% in the pooled analysis, respectively. Programmed death ligand-1 expression tended to be greater among 5-year survivors than in non-survivors (P = 0.0703). Overall survival prolonged with increasing programmed death ligand-1 expression, with 5-year survival rates of 11.8, 21.8 and 41.7% in patients with programmed death ligand-1 expression of <1, ≥1-<50 and ≥50%, respectively. Treatment-related adverse events in ≥10% of patients (pooled analysis) included rash (15.3%), malaise (14.4%), decreased appetite (14.4%), pyrexia (14.4%) and nausea (10.8%). CONCLUSIONS: Long-term survival with nivolumab was observed in patients with squamous or non-squamous non-small cell lung cancer. No new safety signals were reported after ≥5 years of follow-up.

Analysis of DLL3 and ASCL1 in Surgically Resected Small Cell Lung Cancer (HOT1702).

BACKGROUND: Delta-like protein 3 (DLL3) is a Notch ligand that has an important role in the tumorigenesis of small cell lung cancer (SCLC). Recently, rovalpituzumab tesirine (Rova-T), a DLL3-targeted antibody-drug conjugate, has been developed for treating SCLC. DLL3 is a transcriptional target of the achaete-scute homolog-1 (ASCL1) transcription factor, which is involved in pulmonary neuroendocrine cell development. However, the relationship between DLL3 and/or ASCL1 expression and the clinical features of SCLC remains unknown, especially for early-stage resected SCLC. This study aimed to investigate the expression of DLL3 and ASCL1 in resected SCLC samples using immunohistochemical analysis. MATERIALS AND METHODS: We collected 95 surgically resected SCLC samples, which were formalin fixed and paraffin embedded. Immunohistochemistry staining was performed to investigate the correlation between the expression of either DLL3 or ASCL1 and clinicopathological features of study patients. RESULTS: Seventy-seven (83%) of 93 immunohistochemically evaluable samples were positive for DLL3 (expression in ≥1% of tumor cells), and DLL3-high expression (≥75%) was observed in 44 samples (47%). Sixty-one (64%) of 95 samples were positive for ASCL1 (expression in ≥5% of tumor cells). A positive correlation was observed between DLL3 and ASCL1 expression. DLL3 and ASCL1 expression were not associated with survival in SCLC patients. DLL3 was more prevalent in patients with advanced clinical disease. CONCLUSION: DLL3 and ASCL1 were highly expressed in patients with surgically resected SCLC. DLL3 and ASCL1 may be targets for the treatment of SCLC. IMPLICATIONS FOR PRACTICE: This article examines the relationship between delta-like protein 3 (DLL3) and achaete-scute homolog-1 (ASCL1) protein expression with the clinical features of 95 surgically resected small cell lung cancer (SCLC). DLL3 is attracting attention because rovalpituzumab tesirine (Rova-T), a DLL3-targeted antibody-drug conjugate, was developed recently. DLL3 and ASCL1 were highly expressed in patients with surgically resected SCLC. DLL3 and ASCL1 may be targets for the treatment of early-stage SCLC, including with Rova-T.

Theoretical and computational investigations of geometrical, electronic and spin structures of the CaMn4 OX (X = 5, 6) cluster in the Kok cycle Si (i = 0-3) of oxygen evolving complex of photosystem II.

The optimized geometries of the CaMn4 OX (X = 5, 6) cluster in the oxygen evolving complex (OEC) of photosystem II (PSII) by large-scale quantum mechanics (QM) and molecular mechanics (MM) calculations are compared with recent serial femtosecond crystallography (SFX) results for the Si (i = 0-3) states. The valence states of four Mn ions by the QM/MM calculations are also examined in relation to the experimental results by the X-ray emission spectroscopy (XES) for the Si intermediates. Geometrical and valence structures of right-opened Mn-hydroxide, Mn-oxo and Mn-peroxide intermediates in the S3 state are investigated in detail in relation to recent SFX and XES experiments for the S3 state. Interplay between theory and experiment indicates that the Mn-oxo intermediate is a new possible candidate for the S3 state. Implications of the computational results are discussed in relation to possible mechanisms of the oxygenoxygen bond formation for water oxidation in OEC of PSII.

Phase II trial of S-1 plus cisplatin combined with bevacizumab for advanced non-squamous non-small cell lung cancer (TCOG LC-1202).

BACKGROUND: S-1 plus cisplatin is a standard chemotherapy regimen for advanced non-small cell lung cancer (NSCLC). The addition of bevacizumab has been shown to significantly improve overall survival (OS) in patients with advanced non-squamous (NSq) NSCLC who received carboplatin plus paclitaxel, however, failed to show an OS advantage in patients who received cisplatin plus gemcitabine. METHODS: Chemotherapy-naive patients with Stage IIIB, IV or recurrent non-SQ NSCLC were treated with a 3-week cycle of S-1 80 mg/m2 on days 1-14, cisplatin 60 mg/m2 on day 8 and bevacizumab 15 mg/kg on day 8 for 4-6 cycles. Patients without progressive disease (PD) received maintenance bevacizumab 15 mg/kg on day 1 with a 3-week cycle and S-1 80 mg/m2 every other day. The primary endpoint was progression-free survival (PFS). Secondary endpoints were objective response rate (ORR), OS, toxicity profile and Quality of life (QOL). RESULTS: From June 2013 to January 2015, 39 eligible patients were enrolled from eight institutions. Thirty-one patients (79%) completed four cycles of induction chemotherapy, and maintenance chemotherapy was initiated in 23 patients (59%). Median PFS, OS and ORR were 7.3 months (95% CI: 5.9-8.7), 21.4 months (95% CI: 14.7-not reached) and 64%, respectively. The most common grade 3/4 toxicities were leukopenia (12.8%), neutropenia (23.0%) and hypertension (28.2%). QOL analyses showed detrimental effects after initiation of the regimen. CONCLUSIONS: S-1 plus cisplatin in combination with bevacizumab met the primary endpoint in patients with advanced NSq-NSCLC. RR was anticipated to be high with acceptable toxicities.

A phase II study of carboplatin, pemetrexed, and bevacizumab followed by erlotinib and bevacizumab maintenance for non-squamous non-small cell lung cancer with wild-type EGFR (HOT1101).

BACKGROUND: This study evaluated the efficacy and safety of switch maintenance erlotinib and bevacizumab after induction therapy with carboplatin/pemetrexed/bevacizumab for non-squamous non-small cell lung cancer (NSCLC) with wild-type EGFR. METHODS: Enrolled patients had treatment-naïve, advanced non-squamous NSCLC with wild-type EGFR. Carboplatin [area under the curve (AUC) 5.0], pemetrexed (500 mg/m2) and bevacizumab (15 mg/kg) were administered on day 1 every 3 weeks for 4-6 cycles. Maintenance therapy with erlotinib (150 mg/body) on day 1 through 21 plus bevacizumab on day 1 every 3 weeks was continued until disease progression or unacceptable toxicity. The primary endpoint was 6-month progression-free survival (PFS); secondary endpoints included overall survival (OS), overall response rate (ORR), toxicity, and quality of life (QOL). RESULTS: Fifty-one patients were enrolled between September 2011 and June 2014. The median number of cycles for induction and maintenance therapy was 4 (range 1-6) and 4 (range 1-20). Twenty-nine patients (58%) received maintenance therapy. The 6-month PFS rate was 59.5% [95% confidence interval (CI) 45.0-72.6%]. The ORR was 48.0% (95% CI 34.8-61.5%), and disease control rate was 86.0% (95% CI 73.8-93.0%). The median PFS and OS were 6.5 months (95% CI 5.8-7.2 months) and 21.4 months (95% CI 15.9-26.9 months), respectively. Although grades ≥ 3 adverse events were observed in 33 patients (66.0%), most were hematologic; there was no febrile neutropenia. QOL was maintained throughout treatment. CONCLUSIONS: Carboplatin/pemetrexed/bevacizumab followed by erlotinib and bevacizumab maintenance showed modest efficacy and was well tolerated in non-squamous NSCLC patients with wild-type EGFR. TRIAL REGISTRATION: UMIN000005872.

Health care resource use among patients with advanced non-small cell lung cancer: the PIvOTAL retrospective observational study.

BACKGROUND: Data are scarce regarding real-world health care resource use (HCRU) for non-small cell lung cancer (NSCLC). An understanding of current clinical practices and HCRU is needed to provide a benchmark for rapidly evolving NSCLC management recommendations and therapeutic options. The objective of this study was to describe real-world HCRU for patients with advanced NSCLC. METHODS: This multinational, retrospective chart review study was conducted at academic and community oncology sites in Italy, Spain, Germany, Australia, Japan, South Korea, Taiwan, and Brazil. Deidentified data were drawn from medical records of 1440 adults (≥18 years old) who initiated systemic therapy (2011 to mid-2013) for a new, confirmed diagnosis of advanced or metastatic (stage IIIB or IV) NSCLC. We summarized HCRU associated with first and subsequent lines of systemic therapy for advanced/metastatic NSCLC. RESULTS: The proportion of patients who were hospitalized at least once varied by country from 24% in Italy to 81% in Japan during first-line therapy and from 22% in Italy to 84% in Japan during second-line therapy; overall hospitalization frequency was 2.5-11.1 per 100 patient-weeks, depending on country. Emergency visit frequency also varied among countries (overall from 0.3-5.9 per 100 patient-weeks), increasing consistently from first- through third-line therapy in each country. The outpatient setting was the most common setting of resource use. Most patients in the study had multiple outpatient visits in association with each line of therapy (overall from 21.1 to 59.0 outpatient visits per 100 patient-weeks, depending on country). The use of health care resources showed no regular pattern associated with results of tests for activating mutations of the epidermal growth factor receptor (EGFR) gene or anaplastic lymphoma kinase (ALK) gene rearrangements. CONCLUSIONS: HCRU varied across countries. These findings suggest differing approaches to the clinical management of advanced NSCLC among the eight countries. Comparative findings and an understanding of country-specific clinical practices can help to identify areas of need and guide future resource allocation for patients with advanced NSCLC. Further studies evaluating the costs associated with resource use are warranted.

Efficacy and safety of nivolumab in Japanese patients with advanced or recurrent squamous non-small cell lung cancer.

Limited treatment options are available for stage IIIB/IV non-small cell lung cancer (NSCLC). Nivolumab, a programmed cell death-1 immune checkpoint inhibitor antibody, has been shown to be effective for the treatment of NSCLC. The present study investigated the effectiveness and safety of nivolumab in Japanese patients with advanced or recurrent squamous NSCLC that progressed after platinum-containing chemotherapy. In this multicenter phase II study, patients were treated with nivolumab (3 mg/kg, i.v.) every 2 weeks until progressive disease or unacceptable toxicity was seen. Primary endpoint was overall response rate (ORR) assessed by independent radiology review committee (IRC) and secondary endpoints included a study site-assessed ORR, overall survival (OS), progression-free survival (PFS), duration of response, time to response, best overall response (BOR), and safety. The study included 35 patients from 17 sites in Japan. Patients had IRC-assessed ORR of 25.7% (95% CI 14.2, 42.1) and the study site-assessed ORR was 20.0% (95% CI 10.0, 35.9). Median OS, median time to response and median PFS were 16.3 (95% CI 12.4-25.4), 2.7 (range 1.2-5.5) and 4.2 (95% CI 1.4-7.1) months, respectively. The IRC-assessed BOR was partial response, stable disease, and progressive disease for 25.7%, 28.6%, and 45.7% of patients, respectively. Treatment-related adverse events were reported in 24 patients (68.6%), most of which resolved with appropriate treatment including steroid therapy or discontinuation of nivolumab. Nivolumab was effective and well tolerated in Japanese patients with advanced or recurrent squamous NSCLC that progressed after platinum-containing chemotherapy. CLINICAL TRIAL REGISTRATION NUMBER: JapicCTI-132072.

Large-scale QM/MM calculations of the CaMn4O5 cluster in the S3 state of the oxygen evolving complex of photosystem II. Comparison between water-inserted and no water-inserted structures.

Large-scale QM/MM calculations were performed to elucidate an optimized geometrical structure of a CaMn4O5 cluster with and without water insertion in the S3 state of the oxygen evolving complex (OEC) of photosystem II (PSII). The left (L)-opened structure was found to be stable under the assumption of no hydroxide anion insertion in the S3 state, whereas the right (R)-opened structure became more stable if one water molecule is inserted to the Mn4Ca cluster. The optimized Mna(4)-Mnd(1) distance determined by QM/MM was about 5.0 Å for the S3 structure without an inserted hydroxide anion, but this is elongated by 0.2-0.3 Å after insertion. These computational results are discussed in relation to the possible mechanisms of O-O bond formation in water oxidation by the OEC of PSII.

Chemical Equilibrium Models for the S3 State of the Oxygen-Evolving Complex of Photosystem II.

We have performed hybrid density functional theory (DFT) calculations to investigate how chemical equilibria can be described in the S3 state of the oxygen-evolving complex in photosystem II. For a chosen 340-atom model, 1 stable and 11 metastable intermediates have been identified within the range of 13 kcal mol(-1) that differ in protonation, charge, spin, and conformational states. The results imply that reversible interconversion of these intermediates gives rise to dynamic equilibria that involve processes with relocations of protons and electrons residing in the Mn4CaO5 cluster, as well as bound water ligands, with concomitant large changes in the cluster geometry. Such proton tautomerism and redox isomerism are responsible for reversible activation/deactivation processes of substrate oxygen species, through which Mn-O and O-O bonds are transiently ruptured and formed. These results may allow for a tentative interpretation of kinetic data on substrate water exchange on the order of seconds at room temperature, as measured by time-resolved mass spectrometry. The reliability of the hybrid DFT method for the multielectron redox reaction in such an intricate system is also addressed.

Geometric and electronic structures of the synthetic Mn4CaO4 model compound mimicking the photosynthetic oxygen-evolving complex.

Water oxidation by photosystem II (PSII) converts light energy into chemical energy with the concomitant production of molecular oxygen, both of which are indispensable for sustaining life on Earth. This reaction is catalyzed by an oxygen-evolving complex (OEC) embedded in the huge PSII complex, and its mechanism remains elusive in spite of the extensive studies of the geometric and electronic structures. In order to elucidate the water-splitting mechanism, synthetic approaches have been extensively employed to mimic the native OEC. Very recently, a synthetic complex [Mn4CaO4(Bu(t)COO)8(py)(Bu(t)COOH)2] (1) closely mimicking the structure of the native OEC was obtained. In this study, we extensively examined the geometric, electronic and spin structures of 1 using the density functional theory method. Our results showed that the geometric structure of 1 can be accurately reproduced by theoretical calculations, and revealed many similarities in the ground valence and spin states between 1 and the native OEC. We also revealed two different valence states in the one-electron oxidized state of 1 (corresponding to the S2 state), which lie in the lower and higher ground spin states (S = 1/2 and S = 5/2), respectively. One remarkable difference between 1 and the native OEC is the presence of a non-negligible antiferromagnetic interaction between the Mn1 and Mn4 sites, which slightly influenced their ground spin structures (spin alignments). The major reason causing the difference can be attributed to the short Mn1-O5 and Mn1-Mn4 distances in 1. The introduction of the missing O4 atom and the reorientation of the Ca coordinating ligands improved the Mn1-O5 and Mn1-Mn4 distances comparable to the native OEC. These modifications will therefore be important for the synthesis of further advanced model complexes more closely mimicking the native OEC beyond 1.

Open-label, randomized, comparative, phase III study on effects of reducing steroid use in combination with Palonosetron.

The purpose of this study is to compare the efficacy of a single administration of dexamethasone (DEX) on day 1 against DEX administration on days 1-3 in combination with palonosetron (PALO), a second-generation 5-HT3 receptor antagonist, for chemotherapy-induced nausea and vomiting (CINV) in non-anthracycline and cyclophosphamide (AC) moderately-emetogenic chemotherapy (MEC). This phase III trial was conducted with a multi-center, randomized, open-label, non-inferiority design. Patients who received non-AC MEC as an initial chemotherapy were randomly assigned to either a group administered PALO (0.75 mg, i.v.) and DEX (9.9 mg, i.v.) prior to chemotherapy (study treatment group), or a group administered additional DEX (8 mg, i.v. or p.o.) on days 2-3 (control group). The primary endpoint was complete response (CR) rate. The CR rate difference was estimated by logistic regression with allocation factors as covariates. The non-inferiority margin was set at -15% (study treatment group - control group). From April 2011 to March 2013, 305 patients who received non-AC MEC were randomly allocated to one of two study groups. Overall, the CR rate was 66.2% in the study treatment group (N = 151) and 63.6% in the control group (N = 154). PALO plus DEX day 1 was non-inferior to PALO plus DEX days 1-3 (difference, 2.5%; 95% confidence interval [CI]: -7.8%-12.8%; P-value for non-inferiority test = 0.0004). There were no differences between the two groups in terms of complete control rate (64.9 vs 61.7%) and total control rate (49.7% vs 47.4%). Anti-emetic DEX administration on days 2-3 may be eliminated when used in combination with PALO in patients receiving non-AC MEC.

Aqueous nanosilica dispersants for carbon nanotube.

Nanosilicas can disperse single-wall carbon nanotube (SWCNT) in aqueous solution efficiently; SWCNTs are stably dispersed in aqueous media for more than 6 months. The SWCNT dispersing solution with nanosilica can produce highly conductive transparent films which satisfy the requirements for application to touch panels. Even multiwall carbon nanotube can be dispersed easily in aqueous solution. The highly stable dispersion of SWCNTs in the presence of nanosilica is associated with charge transfer interaction which generates effective charges on the SWCNT particles, giving rise to electrostatic repulsion between the SWCNTs in the aqueous solution. Adhesion of charged nanosilicas on SWCNTs in the aqueous solution and a marked depression of the S11 peak of optical absorption spectrum of the SWCNT with nanosilicas suggest charge transfer interaction of nanosilicas with SWCNT. Thus-formed isolated SWCNTs are fixed on the flexible three-dimensional silica jelly structure in the aqueous solution, leading to the uniform and stable dispersion of SWCNTs.

Efficacy of chemotherapy after first-line gefitinib therapy in EGFR mutation-positive advanced non-small cell lung cancer-data from a randomized Phase III study comparing gefitinib with carboplatin plus paclitaxel (NEJ002).

OBJECTIVE: Epidermal growth factor receptor tyrosine kinase inhibitors are effective as first-line therapy for advanced non-small cell lung cancer patients harboring epidermal growth factor receptor mutations. However, it is unknown whether second-line platinum-based chemotherapy after epidermal growth factor receptor tyrosine kinase inhibitor therapy could lead to better outcomes. We evaluated the efficacy of second-line platinum-based chemotherapy after gefitinib for advanced non-small cell lung cancers harboring epidermal growth factor receptor mutations (the NEJ002 study). METHODS: Seventy-one non-small cell lung cancers, treated with gefitinib as first-line therapy and then receiving platinum-based chemotherapy as second-line therapy were evaluated in NEJ002. Patients were evaluated for antitumor response to second-line chemotherapy by computed tomography according to the criteria of the Response Evaluation Criteria in Solid Tumors group (version 1.0). RESULTS: Of the 71 patients receiving platinum-based chemotherapy after first-line gefitinib, a partial response was documented in 25.4% (18/71), stable disease in 43.7% (31/71) and progression of disease in 21.1% (15/71). The objective response and disease control rates were 25.4% (18/71) and 69% (49/71), respectively. There was no significant difference between first- and second-line chemotherapy in objective response and disease control rates for advanced non-small cell lung cancer harboring activating epidermal growth factor receptor mutations. In the analysis of epidermal growth factor receptor mutation types, the objective responses of deletions in exon 19 and a point mutation in exon 21 (L858R) were 27.3% (9/33) and 28.1% (9/32), respectively, but these differences between objective response rates were not significant. CONCLUSIONS: The efficacy of second-line platinum-based chemotherapy followed at progression by gefitinib was similar to first-line platinum-based chemotherapy, and epidermal growth factor receptor mutation types did not influence the efficacy of second-line platinum-based chemotherapy.

Similarities of artificial photosystems by ruthenium oxo complexes and native water splitting systems.

The nature of chemical bonds of ruthenium(Ru)-quinine(Q) complexes, mononuclear [Ru(trpy)(3,5-t-Bu(2)Q)(OH(2))](ClO(4))(2) (trpy = 2,2':6',2''-terpyridine, 3,5-di-tert-butyl-1,2-benzoquinone) (1), and binuclear [Ru(2)(btpyan)(3,6-di-Bu(2)Q)(2)(OH(2))](2+) (btpyan = 1,8-bis(2,2':6',2''-terpyrid-4'-yl)anthracene, 3,6-t-Bu(2)Q = 3,6-di-tert-butyl-1,2-benzoquinone) (2), has been investigated by broken-symmetry (BS) hybrid density functional (DFT) methods. BS DFT computations for the Ru complexes have elucidated that the closed-shell structure (2b) Ru(II)-Q complex is less stable than the open-shell structure (2bb) consisting of Ru(III) and semiquinone (SQ) radical fragments. These computations have also elucidated eight different electronic and spin structures of tetraradical intermediates that may be generated in the course of water splitting reaction. The Heisenberg spin Hamiltonian model for these species has been derived to elucidate six different effective exchange interactions (J) for four spin systems. Six J values have been determined using total energies of the eight (or seven) BS solutions for different spin configurations. The natural orbital analyses of these BS DFT solutions have also been performed in order to obtain natural orbitals and their occupation numbers, which are useful for the lucid understanding of the nature of chemical bonds of the Ru complexes. Implications of the computational results are discussed in relation to the proposed reaction mechanisms of water splitting reaction in artificial photosynthesis systems and the similarity between artificial and native water splitting systems.

[Feasibility of short volume hydration in patients with lung cancer treated with Cisplatin-containing chemotherapy].

The aim of this study was to examine the feasibility of short volume hydration (SH) with magnesium and mannitol versus normal high volume hydration (NH) for targeting nephrotoxicity in lung cancer patients treated with cisplatin (CDDP)- containing chemotherapy. Between January 2012 and February 2013, 28 patients with lung cancer at a single institute received CDDP-containing chemotherapy. We retrospectively evaluated the incidence of nephrotoxicity during the first cycle of chemotherapy. Nephrotoxicity was compared between the SH and NH regimens according to the Common Terminology Criteria for Adverse Events(CTCAE) version 4.0. Laboratory data were collected from the 2 regimen groups at pre-treatment, during the first cycle, and post-treatment and were compared by univariate analysis. Twelve patients received the SH regimen with magnesium and mannitol, and 16 patients received the NH regimen. Only 1 patient in the NH regimen group had Grade 2 increases in serum creatinine. On the other hand, no patient in the SH regimen group had increased serum creatinine. There was no significant difference in the incidence of nephrotoxicity between the 2 regimen groups during the first cycle of CDDP induction(p=0.38). The SH regimen with magnesium and mannitol is feasible in lung cancer patients treated with CDDP-containing chemotherapy.

Water oxidation chemistry of a synthetic dinuclear ruthenium complex containing redox-active quinone ligands.

We investigated theoretically the catalytic mechanism of electrochemical water oxidation in aqueous solution by a dinuclear ruthenium complex containing redox-active quinone ligands, [Ru2(X)(Y)(3,6-tBu2Q)2(btpyan)](m+) [X, Y = H2O, OH, O, O2; 3,6-tBu2Q = 3,6-di-tert-butyl-1,2-benzoquinone; btpyan =1,8-bis(2,2':6',2″-terpyrid-4'-yl)anthracene] (m = 2, 3, 4) (1). The reaction involves a series of electron and proton transfers to achieve redox leveling, with intervening chemical transformations in a mesh scheme, and the entire molecular structure and motion of the catalyst 1 work together to drive the catalytic cycle for water oxidation. Two substrate water molecules can bind to 1 with simultaneous loss of one or two proton(s), which allows pH-dependent variability in the proportion of substrate-bound structures and following pathways for oxidative activation of the aqua/hydroxo ligands at low thermodynamic and kinetic costs. The resulting bis-oxo intermediates then undergo endothermic O-O radical coupling between two Ru(III)-O(•) units in an anti-coplanar conformation leading to bridged µ-peroxo or µ-superoxo intermediates. The µ-superoxo species can liberate oxygen with the necessity for the preceding binding of a water molecule, which is possible only after four-electron oxidation is completed. The magnitude of catalytic current would be limited by the inherent sluggishness of the hinge-like bending motion of the bridged µ-superoxo complex that opens up the compact, hydrophobic active site of the catalyst and thereby allows water entry under dynamic conditions. On the basis of a newly proposed mechanism, we rationalize the experimentally observed behavior of electrode kinetics with respect to potential and discuss what causes a high overpotential for water oxidation by 1.

A phase II study of amrubicin as a third-line or fourth-line chemotherapy for patients with non-small cell lung cancer: Hokkaido Lung Cancer Clinical Study Group Trial (HOT) 0901.

Amrubicin, a third-generation synthetic anthracycline agent, has favorable clinical activity and acceptable toxicity for the treatment of patients with non-small cell lung cancer (NSCLC) and small cell lung cancer. We conducted this study to evaluate the efficacy and safety of amrubicin for advanced NSCLC patients as a third- or fourth-line therapy. Eligible patients had recurrent or refractory advanced NSCLC after second- or third-line therapy. Patients received amrubicin, 35 mg/m(2) i.v. on days 1-3 every 3 weeks. The primary endpoint was the disease control rate (DCR). Secondary endpoints were the overall survival (OS) time, progression-free survival (PFS) time, response rate, and toxicity profile. Of the 41 patients enrolled, 26 received amrubicin as a third-line and 15 received it as a fourth-line therapy. The median number of treatment cycles was two (range, 1-9). Objective responses were complete response (n = 0), partial response (n = 4), stable disease (n = 21), progressive disease (n = 15), and not evaluable (n = 1), resulting in a DCR of 61.0% (95% confidence interval, 46.0%-75.9%). The overall response rate was 9.8% (95% confidence interval, 0.6%-18.8%). The median PFS interval was 3.0 months, median OS time was 12.6 months, and 1-year survival rate was 53.7%. Grade 3 or 4 hematological toxicities were neutropenia (68%), anemia (12%), thrombocytopenia (12%), and febrile neutropenia (17%). Nonhematological toxicities were mild and reversible. No treatment-related deaths were observed. Amrubicin showed significant clinical activity with manageable toxicities as a third- or fourth-line therapy for patients with advanced NSCLC. This study provides relevant data for routine practice and future prospective trials evaluating third- or fourth-line treatment strategies for patients with advanced NSCLC.