Investigation of Hypersensitivity Reactions in Carboplatin Desensitization Therapy.

BACKGROUND/AIM: Carboplatin is a key drug in the treatment of ovarian cancer, but hypersensitivity reactions (HSRs) may occur with repeated use. PATIENTS AND METHODS: Thirty-seven ovarian cancer patients treated with carboplatin desensitization therapy were reviewed retrospectively. The treatment completion rate and toxicity were examined. RESULTS: The carboplatin desensitization completion rate was 86.5%. Toxicity was Grade 0, 1, 2, and 3 in 17, 5, 10, and 5 patients, respectively. Erythema was the most frequent toxicity (36.8%), most commonly affecting the arm (23.5%). Furthermore, all HSRs were classified into: skin, respiratory, digestive, circulatory, and neurological. The completion rate of desensitization was significantly lower in patients with two or more target organs affected (p<0.001). CONCLUSION: The main symptoms of HSRs, the most common sites of HSRs, and the criteria for discontinuing desensitization therapy identified in this study are useful information for the safe implementation of carboplatin desensitization therapy.

Gene Deletion of Microsomal Prostaglandin E Synthase-1 Suppresses Chemically Induced Skin Carcinogenesis.

BACKGROUND/AIM: Microsomal prostaglandin (PG) E synthase-1 (mPGES-1) is a terminal enzyme in PGE2 synthesis and highly expressed in several cancers. In this study, to reveal the involvement of mPGES-1 in skin carcinogenesis, the effect of mPGES-1 deficiency on two-stage skin carcinogenesis in mice was investigated. MATERIALS AND METHODS: A two-stage skin carcinogenesis model using 7,12-dimethylbenz[a]anthracene (DMBA) as an initiator and 12-O-tetradecanoylphorbol-13-acetate (TPA) as a promoter was applied on mPGES-1 knockout (KO) mice and littermate wild-type mice of a Balb/c genetic background. RESULTS: DMBA/TPA-induced skin carcinogenesis was suppressed in mPGES-1 KO mice. The induction of IL-17 and other inflammatory cytokines by TPA was also suppressed by mPGES-1 deficiency, although DMBA-induced apoptosis was not affected. CONCLUSION: mPGES-1 promotes chemically induced skin carcinogenesis and might play an important role in the TPA-induced promotion phase of the two-stage skin carcinogenesis model. mPGES-1 inhibition may be a therapeutic target for skin cancer.

Oxaliplatin induces prostaglandin E2 release in vascular endothelial cells.

PURPOSE: Oxaliplatin (L-OHP) is known to induce adverse reactions at the injection site, including vascular pain, but the underlying mechanisms have not been clarified. Vascular pain during intravenous L-OHP administration can be inhibited by taking non-steroidal anti-inflammatory drugs (NSAIDs). In this study, we investigated the involvement of the arachidonic acid cascade and prostaglandin (PG) E2 and 15d-PGJ2 in vascular pain sensation during intravenous delivery of L-OHP. METHODS: Cultured normal human umbilical cord vein endothelial cells (HUVECs) were treated with L-OHP or L-OHP + NSAID flurbiprofen for 2 h and analyzed for the release of PGE2 and 15d-PGJ2 into culture supernatant by ELISA. RESULTS: The results showed that L-OHP significantly and dose-dependently increased PGE2 secretion by HUVECs; however, flurbiprofen effectively prevented PGE2 increase. On the other hand, cisplatin, another platinum anticancer drug, did not stimulate PGE2 production. Other PGs, including 15d-PGJ2, 6-keto PGF1α, PGF2α, and PGD2 were not increased by L-OHP or cisplatin. Protein expression analysis revealed that cyclooxygenase 1 and cytoplasmic PGE synthase involved in constitutive PG metabolism were expressed in HUVECs but not affected by L-OHP exposure. CONCLUSIONS: This study indicates that L-OHP treatment specifically upregulated PGE2 secretion by vascular endothelial cells, which may contribute to vascular pain, and that NSAIDs can be used to inhibit PGE2 release and attenuate L-OHP-induced hyperalgesia.

KRAS and EGFR Amplifications Mediate Resistance to Rociletinib and Osimertinib in Acquired Afatinib-Resistant NSCLC Harboring Exon 19 Deletion/T790M in EGFR.

The critical T790M mutation in EGFR, which mediates resistance to first- and second-generation EGFR tyrosine kinase inhibitors (TKI; gefitinib, erlotinib, and afatinib), has facilitated the development of third-generation mutation-selective EGFR TKIs (rociletinib and osimertinib). We previously reported heterogeneous afatinib-resistant mechanisms, including emergence of T790M-EGFR, and responses to third-generation EGFR TKIs. Here, we used afatinib-resistant lung adenocarcinoma cells [AfaR (formerly AFR3) cells], carrying exon 19 deletion/T790M in EGFR To identify the novel resistance mechanisms in post-afatinib treatment, RocR1/RocR2 and OsiR1/OsiR2 cells were established using increasing concentrations of rociletinib and osimertinib, respectively. Attenuation of exon 19 deletion and T790M was confirmed in both rociletinib-resistant cells; in addition, EGFR and KRAS amplification was observed in RocR1 and RocR2, respectively. Significant KRAS amplification was observed in the osimertinib-resistant cell lines, indicating a linear and reversible increase with increased osimertinib concentrations in OsiR1 and OsiR2 cells. OsiR1 cells maintained osimertinib resistance with KRAS amplification after osimertinib withdrawal for 2 months. OsiR2 cells exhibited KRAS attenuation, and osimertinib sensitivity was entirely recovered. Phospho-EGFR (Y1068) and growth factor receptor-bound protein 2 (GRB2)/son of sevenless homolog 1 (SOS1) complex was found to mediate osimertinib resistance in OsiR1 cells with sustained KRAS activation. After 2 months of osimertinib withdrawal, this complex was dissociated, and the EGFR signal, but not the GRB2/SOS1 signal, was activated. Concomitant inhibition of MAPK kinase and EGFR could overcome osimertinib resistance. Thus, we identified a heterogeneous acquired resistance mechanism for third-generation EGFR TKIs, providing insights into the development of novel treatment strategies.

Coadministration of cytotoxic chemotherapeutic agents with irinotecan is a risk factor for irinotecan-induced cholinergic syndrome in Japanese patients with cancer.

BACKGROUND: Cholinergic syndrome is an acute adverse event frequently observed in patients administered irinotecan, and can sometimes negatively affect their quality of life. In some manifestations of the syndrome such as bradycardia, careful monitoring of patients is advised. In this study, we retrospectively investigated the risk factors associated with irinotecan-induced cholinergic syndrome in Japanese patients with cancer. METHODS: Patients who received irinotecan-based chemotherapy between April 2014 and June 2018 were examined. Patient backgrounds and clinical data during the first cycle of an irinotecan-containing regimen, including cholinergic syndrome manifestation within 24 h after the start of treatment, were collected from medical records. Univariate and multivariate analyses were performed to assess the risk of irinotecan-induced cholinergic syndrome. RESULTS: Among 179 patients administered an irinotecan-containing regimen, 51 experienced cholinergic syndrome after the initiation of treatment. The most common symptom was sweating followed by diarrhea, abdominal pain, lacrimation, and nasal discharge. 42 patients developed symptoms of cholinergic syndrome during their first treatment with irinotecan. Multivariate analyses revealed that the incidences of cholinergic syndrome in patients administered 2 or 3 chemotherapeutic agents; i.e., irinotecan plus 1 or 2 other cytotoxic anticancer drug(s), were significantly higher than that in patients administered irinotecan alone [odds ratio (OR) 4.35, 95% confidence interval (CI) 1.5-12, p = 0.0053 and OR 4.50, 95% CI 1.5-14, p = 0.0093, respectively]. The addition of a molecularly targeted drug did not affect the incidence of cholinergic syndrome. CONCLUSION: The incidence rate of irinotecan-induced cholinergic syndrome increased concomitantly with the addition of cytotoxic chemotherapeutic agents administered.

Anti-inflammatory effects of new catechin derivatives in a hapten-induced mouse contact dermatitis model.

Contact dermatitis is a common skin disease, with various treatments available to dermatologists. According to general guidelines, the first line of treatment involves topical steroids; however, this treatment has application-site restrictions in order to avoid adverse cutaneous events. Accordingly, increased demand exists for the development of new treatments. In Japan, the recent use of catechin-containing health foods and their beneficial effects has attracted attention. Indeed, several studies have examined the anticancer, anti-obesity, anti-inflammatory, and antioxidant effects of catechins. In this study, we synthesized planar catechin (PC) from natural (+)-catechin, and further chemically modified it with the intent to clarify the anti-inflammatory and antioxidant effects of new catechin derivatives. Methylate-PC (methyl PC) and acetylate-PC (acetyl PC) were modified to increase lipid solubility. Their antioxidant effects were examined with electron spin resonance by evaluating the ability to remove hydroxyl radicals. In vitro, the antioxidant effects were in the order of PC > (+)-catechin > acetyl PC > methyl PC. In addition, we used a 1-fluoro-2,4-dinitrobenzene (DNFB)-induced allergic contact dermatitis model in BALB/c mice. Our results demonstrated that catechin derivatives inhibited ear swelling induced by DNFB, with acetyl PC demonstrating a greater inhibitory effect than PC and methyl PC. Moreover, acetyl PC downregulated the mRNA levels of inflammatory cytokines, including tumor necrosis factor-alpha, interleukin (IL)-1ß, and IL-4, as well as myeloperoxidase activity, in the ear tissue of DNFB-treated mice. Collectively, our novel findings suggest that catechin derivatives may be a promising new choice for the treatment of contact dermatitis.

Cost-minimization analysis of adjuvant chemotherapy regimens given to patients with colorectal cancer in Japan.

BACKGROUND: Consideration of medical costs as well as effectiveness and adverse events is rapidly been becoming an important factor in the selection of chemotherapy regimens. However, practical data on the costs of chemotherapy are scarce. We clinically estimated the medical costs of 6 adjuvant chemotherapy regimens for colorectal cancer on the basis of clinical and cost-related data and compared their cost-effectiveness by cost-minimization analyses. METHODS: All patients who received adjuvant chemotherapy for colorectal cancer between April 2012 and May 2015 at four hospitals affiliated with Showa University were studied retrospectively. Clinical and cost data related to adjuvant chemotherapy were collected from medical records and medical fee receipt data, respectively. Six adjuvant chemotherapy regimens were studied: capecitabine and oxaliplatin (CapeOX); 5-fluorouracil (5-FU), ℓ-leucovorin (LV), and oxaliplatin (modified FOLFOX6 [mFOLFOX6]); 5-FU and LV (5-FU/LV); tegafur and uracil (UFT), and LV (UFT/LV); capecitabine; and tegafur, gimeracil and oteracil (S-1). The regimens were divided into 2 groups according to whether or not they contained oxaliplatin because of the difference in effectiveness. Cost-minimization analyses, where relative costs of regimens showing equivalent effectiveness were simply compared, were performed to evaluate the cost-effectiveness of the regimens in each group. RESULTS: A total of 154 patients with colorectal cancer received adjuvant chemotherapy during the study period. Fifty-seven patients were treated with CapeOX, 10 with mFOLFOX6, 38 with UFT/LV, 20 with capecitabine, and 29 with S-1. No patient received 5-FU/LV. The total costs of oxaliplatin-containing regimens were significantly higher than those of oxaliplatin non-containing regimens. The high cost of oxaliplatin, but not the costs of drugs or various tests for the treatment of adverse events, was the primary reason for the higher costs of the oxaliplatin-containing regimens. The cost-effectiveness of the oxaliplatin-containing regimens CapeOX and mFOLFOX6 were comparable. Among the oxaliplatin non-containing regimens, the cost-effectiveness of S-1 and capecitabine was superior to that of UFT/LV. CONCLUSION: Thus, we provided the cost-effectiveness data of 5 adjuvant chemotherapy regimens for colorectal cancer based on practical clinical and cost data from Japanese patients. The results can be included as a factor in regimen selection because these results would represent the real world. TRIAL REGISTRATION: This study is a retrospective observational study and does not include any health care interventions. Therefore, we did not register the protocol of this study.

Assessment of Injection Site Reactions for Peripheral Intravenous Oxaliplatin Infusion and Potential Remedies.

We investigated the medical and nursing records of 19 patients with unresectable advanced recurrent colorectal cancers treated using oxaliplatin and capecitabine(CapeOX)with or without bevacizumab at the outpatient tumor center of Showa UniversityHospital between November 1, 2009 and November 30, 2011, to clarifydifferences in the incidence of injection site reactions according to the use or non-use of an intravenous infusion solution warming device. Vascular pain and other injection site reactions occurred in 13 patients(68.4%). Injection site reactions occurred in 33 of the total of 77 chemotherapytreatments (42.9%). No difference in incidence of injection site reactions was seen according to whether the intravenous infusion solution warmer was used. The most common time to onset of injection site reactions after commencing oxaliplatin administration was 60-90 min, and symptoms were seen to decrease when non-steroidal anti-inflammatorydrugs were coadministered. We intend to leverage these studyfindings to demonstrate the mechanism of onset for injection site reactions and to propose measures for handling adverse drug reactions.

Microsomal prostaglandin E synthase-1 is induced in alzheimer's disease and its deletion mitigates alzheimer's disease-like pathology in a mouse model.

Epidemiological studies have suggested that long-term use of nonsteroidal anti-inflammatory drugs that inhibit cyclooxygenase (COX) activity can moderate the onset or progression of Alzheimer's disease (AD). Thus it has been suggested that prostaglandin E2 (PGE2 ), a major end-product of COX, may play a pathogenic role in AD, but the involvement of PGE synthase (PGES), a terminal enzyme downstream from COX, has not been fully elucidated. Here we found that, among three PGES enzymes, only microsomal PGES-1 (mPGES-1) is induced, and its expression is associated with ß-amyloid (Aß) plaques in the cerebral cortex in human AD patients and in Tg2576 mice, a transgenic AD mouse model. Furthermore, to investigate whether mPGES-1 contributes to AD-like pathology, we bred mPGES-1-deficient mice with Tg2576 mice. We found that mPGES-1 deletion reduced the accumulation of microglia around senile plaques and attenuated learning impairments in Tg2576 mice. These results indicated that mPGES-1 is induced in the AD brain and thus plays a role in AD pathology. Blockage of mPGES-1 could form the basis for a novel therapeutic strategy for patients with AD.

[Advanced curriculum for clinical assessment and skill in new age pharmacist education].

In Showa University School of pharmacy, 7 competencies for outcome-based education were set up in 2011. We are now creating sequential curriculum in order to achieve these competencies. As a member of team medical treatment, pharmacist must share a patient's information with other members, assess each patient's condition, propose the best medication with evidence, and also check the effect of medication. Therefore, many active practices in a hospital and community and problem-based learning (PBL) tutorials are carried out in curriculum in School of Pharmacy. As a training for the future pharmacists who positively perform primary care with responsibility in community pharmacy, students study the method of clinical assessment (assessment of condition of disease from the patient's complain, and choice of appropriate proposal). Furthermore, the exercise and training of parenteral medication, physical assessment, and first aid, etc. are also taken in the curriculums as new clinical skill. The systematic and gradual interprofessional education curriculum for the team medical education has been carried out aiming at training of active members in medical team in a hospital and community. At this symposium, I will introduce these systematic advanced curriculums for the pharmacist of a new age, and to show the usefulness and learning effect.

Deletion of microsomal prostaglandin E synthase-1 protects neuronal cells from cytotoxic effects of ß-amyloid peptide fragment 31-35.

Epidemiological studies have suggested that the long-term use of nonsteroidal anti-inflammatory drugs that inhibit cyclooxygenase (COX) activity moderates the onset or progression of Alzheimer's disease (AD). Thus it has been suggested that prostaglandin E(2) (PGE(2)), a major end-product of COX, may play a pathogenic role in AD, but the involvement of PGE synthase (PGES), a terminal enzyme downstream from COX, has not been fully elucidated. To examine the involvement in AD pathology of microsomal PGES-1 (mPGES-1), a PGES enzyme, we here prepared primary cerebral neuronal cells from the cerebri of wild-type and mPGES-1-deficient mice and then treated them with ß-amyloid (Aß) fragment 31-35 (Aß(31-35)), which represents the shortest sequence of native Aß peptide required for neurotoxicity. Treatment of wild-type neuronal cells with Aß(31-35) induced mPGES-1 gene expression and PGE(2) production, followed by significant apoptotic cell death, but apoptosis was not induced in mPGES-1-deficient cells. Furthermore, the combined treatment of Aß(31-35) and PGE(2) induced apoptosis in mPGES-1-deficient neuronal cells. These results indicated that mPGES-1 is induced during Aß-mediated neuronal cell death and is involved in Aß-induced neurotoxicity associated with AD pathology.

A novel Pim-1 kinase inhibitor targeting residues that bind the substrate peptide.

A new screening method using fluorescent correlation spectroscopy was developed to select kinase inhibitors that competitively inhibit the binding of a fluorescently labeled substrate peptide. Using the method, among approximately 700 candidate compounds selected by virtual screening, we identified a novel Pim-1 kinase inhibitor targeting its peptide binding residues. X-ray crystal analysis of the complex structure of Pim-1 with the inhibitor indicated that the inhibitor actually binds to the ATP-binding site and also forms direct interactions with residues (Asp128 and Glu171) that bind the substrate peptide. These interactions, which cause small side-chain movements, seem to affect the binding ability of the fluorescently labeled substrate. The compound inhibited Pim-1 kinase in vitro, with an IC(50) value of 150 nM. Treatment of cultured leukemia cells with the compound reduced the amount of p21 and increased the amount of p27, due to Pim-1 inhibition, and then triggered apoptosis after cell-cycle arrest at the G(1)/S phase. This screening method may be widely applicable for the identification of various new Pim-1 kinase inhibitors targeting the residues that bind the substrate peptide.

The development of N-α-(2-carboxyl)benzoyl-N(5)-(2-fluoro-1-iminoethyl)-l-ornithine amide (o-F-amidine) and N-α-(2-carboxyl)benzoyl-N(5)-(2-chloro-1-iminoethyl)-l-ornithine amide (o-Cl-amidine) as second generation protein arginine deiminase (PAD) inhibitors.

Protein arginine deiminase (PAD) activity is upregulated in a number of human diseases, including rheumatoid arthritis, ulcerative colitis, and cancer. These enzymes, there are five in humans (PADs 1-4 and 6), regulate gene transcription, cellular differentiation, and the innate immune response. Building on our successful generation of F- and Cl-amidine, which irreversibly inhibit all of the PADs, a structure-activity relationship was performed to develop second generation compounds with improved potency and selectivity. Incorporation of a carboxylate ortho to the backbone amide resulted in the identification of N-α-(2-carboxyl)benzoyl-N(5)-(2-fluoro-1-iminoethyl)-l-ornithine amide (o-F-amidine) and N-α-(2-carboxyl)benzoyl-N(5)-(2-chloro-1-iminoethyl)-l-ornithine amide (o-Cl-amidine), as PAD inactivators with improved potency (up to 65-fold) and selectivity (up to 25-fold). Relative to F- and Cl-amidine, the compounds also show enhanced potency in cellulo. As such, these compounds will be versatile chemical probes of PAD function.

Analysis of two major intracellular phospholipases A(2) (PLA(2)) in mast cells reveals crucial contribution of cytosolic PLA(2)α, not Ca(2+)-independent PLA(2)ß, to lipid mobilization in proximal mast cells and distal fibroblasts.

Mast cells release a variety of mediators, including arachidonic acid (AA) metabolites, to regulate allergy, inflammation, and host defense, and their differentiation and maturation within extravascular microenvironments depend on the stromal cytokine stem cell factor. Mouse mast cells express two major intracellular phospholipases A(2) (PLA(2)s), namely group IVA cytosolic PLA(2) (cPLA(2)α) and group VIA Ca(2+)-independent PLA(2) (iPLA(2)ß), and the role of cPLA(2)α in eicosanoid synthesis by mast cells has been well documented. Lipidomic analyses of mouse bone marrow-derived mast cells (BMMCs) lacking cPLA(2)α (Pla2g4a(-/-)) or iPLA(2)ß (Pla2g6(-/-)) revealed that phospholipids with AA were selectively hydrolyzed by cPLA(2)α, not by iPLA(2)ß, during FcεRI-mediated activation and even during fibroblast-dependent maturation. Neither FcεRI-dependent effector functions nor maturation-driven phospholipid remodeling was impaired in Pla2g6(-/-) BMMCs. Although BMMCs did not produce prostaglandin E(2) (PGE(2)), the AA released by cPLA(2)α from BMMCs during maturation was converted to PGE(2) by microsomal PGE synthase-1 (mPGES-1) in cocultured fibroblasts, and accordingly, Pla2g4a(-/-) BMMCs promoted microenvironmental PGE(2) synthesis less efficiently than wild-type BMMCs both in vitro and in vivo. Mice deficient in mPGES-1 (Ptges(-/-)) had an augmented local anaphylactic response. These results suggest that cPLA(2)α in mast cells is functionally coupled, through the AA transfer mechanism, with stromal mPGES-1 to provide anti-anaphylactic PGE(2). Although iPLA(2)ß is partially responsible for PGE(2) production by macrophages and dendritic cells, it is dispensable for mast cell maturation and function.

Fusion of porous isotactic poly(methyl methacrylate) thin films fabricated on silica nanoparticles with stepwise stereocomplex assembly.

Structures of silica nanoparticles coated with stereocomplex thin films composed of isotactic (it) poly(methyl methacrylate) (PMMA) and syndiotactic (st) poly(methacrylic acid) (PMAA) and with porous it-PMMA thin films under gentle stirring or static conditions were analyzed by dynamic light scattering (DLS) and scanning electron microscopy (SEM), respectively. The porous it-PMMA films were fabricated by stepwise stereocomplex assembling of it-PMMA and st-PMAA, and subsequent extraction of the st-PMAA from the films. From DLS results, an evident difference was not observed between the it-PMMA films and the stereocomplex films, whereas the it-PMMA films after 10 h of stirring in acetonitrile/water (4/6, v/v) and drying on a SEM stage fused to form nanostructured networks. The fusion of the it-PMMA films on the silica nanoparticles occurred not by the dissolution of it-PMMA in the mixed solvent, but rather by an interaction of the it-PMMA chains driven by the slight solvation of acetonitrile without dissolution. Thus, leaving the solution at rest would be important for film fusion on the particles, and multiple spherical substrates could promote the crosslinking of the it-PMMA chains on the particles.

Physiological roles of group X-secreted phospholipase A2 in reproduction, gastrointestinal phospholipid digestion, and neuronal function.

Although the secreted phospholipase A(2) (sPLA(2)) family has been generally thought to participate in pathologic events such as inflammation and atherosclerosis, relatively high and constitutive expression of group X sPLA(2) (sPLA(2)-X) in restricted sites such as reproductive organs, the gastrointestinal tract, and peripheral neurons raises a question as to the roles played by this enzyme in the physiology of reproduction, digestion, and the nervous system. Herein we used mice with gene disruption or transgenic overexpression of sPLA(2)-X to clarify the homeostatic functions of this enzyme at these locations. Our results suggest that sPLA(2)-X regulates 1) the fertility of spermatozoa, not oocytes, beyond the step of flagellar motility, 2) gastrointestinal phospholipid digestion, perturbation of which is eventually linked to delayed onset of a lean phenotype with reduced adiposity, decreased plasma leptin, and improved muscle insulin tolerance, and 3) neuritogenesis of dorsal root ganglia and the duration of peripheral pain nociception. Thus, besides its inflammatory action proposed previously, sPLA(2)-X participates in physiologic processes including male fertility, gastrointestinal phospholipid digestion linked to adiposity, and neuronal outgrowth and sensing.

Prostaglandin E synthases: Understanding their pathophysiological roles through mouse genetic models.

Prostaglandin E synthase (PGES), which converts cyclooxygenase (COX)-derived prostaglandin H(2) (PGH(2)) to PGE(2), is known to comprise a group of at least three structurally and biologically distinct enzymes. Two of them are membrane-bound and have been designated as mPGES-1 and mPGES-2. mPGES-1 is a perinuclear protein that is markedly induced by proinflammatory stimuli and downregulated by anti-inflammatory glucocorticoids as in the case of COX-2. It is functionally coupled with COX-2 in marked preference to COX-1. mPGES-2 is synthesized as a Golgi membrane-associated protein, and the proteolytic removal of the N-terminal hydrophobic domain leads to the formation of a mature cytosolic enzyme. This enzyme is rather constitutively expressed in various cells and tissues and is functionally coupled with both COX-1 and COX-2. Cytosolic PGES (cPGES) is constitutively expressed in a wide variety of cells and is functionally linked to COX-1 to promote immediate PGE(2) production. Recently, mice have been engineered with specific deletions in each of these three PGES enzymes. In this review, we summarize the current understanding of the in vivo roles of PGES enzymes by knockout mouse studies and provide an overview of their biochemical properties.

Microsomal prostaglandin E synthase-1 in both cancer cells and hosts contributes to tumour growth, invasion and metastasis.

mPGES-1 (microsomal prostaglandin E synthase-1) is a stimulus-inducible enzyme that functions downstream of COX (cyclo-oxygenase)-2 in the PGE2 (prostaglandin E2)-biosynthesis pathway. Although COX-2-derived PGE2 is known to play a role in the development of various tumours, the involvement of mPGES-1 in carcinogenesis has not yet been fully understood. In the present study, we used LLC (Lewis lung carcinoma) cells with mPGES-1 knockdown or overexpression, as well as mPGES-1-deficient mice to examine the roles of cancer cell- and host-associated mPGES-1 in the processes of tumorigenesis in vitro and in vivo. We found that siRNA (small interfering RNA) silencing of mPGES-1 in LLC cells decreased PGE2 synthesis markedly, accompanied by reduced cell proliferation, attenuated Matrigel invasiveness and increased extracellular matrix adhesion. Conversely, mPGES-1-overexpressing LLC cells showed increased proliferating and invasive capacities. When implanted subcutaneously into wild-type mice, mPGES-1-silenced cells formed smaller xenograft tumours than did control cells. Furthermore, LLC tumours grafted subcutaneously into mPGES-1-knockout mice grew more slowly than did those grafted into littermate wild-type mice, with concomitant decreases in the density of microvascular networks, the expression of pro-angiogenic vascular endothelial growth factor, and the activity of matrix metalloproteinase-2. Lung metastasis of intravenously injected LLC cells was also significantly less obvious in mPGES-1-null mice than in wild-type mice. Thus our present approaches provide unequivocal evidence for critical roles of the mPGES-1-dependent PGE2 biosynthetic pathway in both cancer cells and host microenvironments in tumour growth and metastasis.

Mice lacking ganglioside GM3 synthase exhibit complete hearing loss due to selective degeneration of the organ of Corti.

The ganglioside GM3 synthase (SAT-I), encoded by a single-copy gene, is a primary glycosyltransferase for the synthesis of complex gangliosides. In SAT-I null mice, hearing ability, assessed by brainstem auditory-evoked potentials (BAEP), was impaired at the onset of hearing and had been completely lost by 17 days after birth (P17), showing a deformity in hair cells in the organ of Corti. By 2 months of age, the organ of Corti had selectively and completely disappeared without effect on balance or motor function or in the histology of vestibule. Interestingly, spatiotemporal changes in localization of individual gangliosides, including GM3 and GT1b, were observed during the postnatal development and maturation of the normal inner ear. GM3 expressed in almost all regions of cochlea at P3, but at the onset of hearing it distinctly localized in stria vascularis, spiral ganglion, and the organ of Corti. In addition, SAT-I null mice maintain the function of stria vascularis, because normal potassium concentration and endocochlear potential of endolymph were observed even when they lost the BAEP completely. Thus, the defect of hearing ability of SAT-I null mice could be attributed to the functional disorganization of the organ of Corti, and the expression of gangliosides, especially GM3, during the early part of the functional maturation of the cochlea could be essential for the acquisition and maintenance of hearing function.

Solvent effects on isotactic poly(methyl methacrylate) crystallization and syndiotactic poly(methacrylic acid) incorporation in porous thin films prepared by stepwise stereocomplex assembly.

The solvent effects on the crystallization of porous isotactic (it) poly(methyl methacrylate) (PMMA) thin films as well as the incorporation behavior of syndiotactic (st) poly(methacrylic acid) (PMAA) into the porous films were investigated. The porous it-PMMA thin films were prepared by the extraction of st-PMAA from a stepwise layer-by-layer (LbL) assembly composed of it-PMMA and st-PMAA. The X-ray diffraction pattern of the it-PMMA thin films after immersion in acetonitrile/water (4/6, v/v) showed two characteristic peaks of a crystalline it-PMMA double-stranded helix (2theta = 9 degrees and 14 degrees , d = 0.96 and 0.62 nm). This suggested that acetonitrile promoted the crystallization of the thin films, because water is a nonsolvent for PMMA. The surface structural change of the it-PMMA films was also analyzed by atomic force microscopy. The it-PMMA conformation was maintained after crystallization as observed by infrared spectroscopy. The incorporation percentages of st-PMAA into the porous it-PMMA thin films under various solvent conditions were estimated using a quartz crystal microbalance. The incorporation of st-PMAA decreased as the it-PMMA films crystallized or with growing thickness of the porous it-PMMA films. This suggested that the polymer-polymer interactions and the entanglement of the it-PMMA chains played an important role. The incorporation was promoted as the acetonitrile content in the st-PMAA solution increased, indicating that it was necessary for st-PMAA incorporation to solvate it-PMMA.