Variations in photodynamic diagnosis for bladder cancer due to the quality of endoscopic equipment.

BACKGROUND: Photodynamic diagnosis (PDD)-assisted transurethral resection of bladder tumor (TURBT) has different treatment outcomes across institutions, as seen in conventional TURBT. We retrospectively compared the difference in quality between the two types of endoscopic equipment used for PDD-assisted TURBT in our institution. METHODS: This study enrolled 205 consecutive patients who underwent PDD-assisted TURBT. Patients were divided into two groups according to the endoscopic equipment used for PDD-assisted TURBT: Group A using the conventionally used endoscopic system and Aladuck LS-DLED and Group S using the Storz PDD system. Cystoscopy findings of white light (WL), fluorescence light (FL), and combination (positive if either WL or FL was positive) were recorded, and diagnostic quality of PDD was compared between both groups. RESULTS: Group A had 105 cases and 336 specimens, while Group S had 100 cases and 361 specimens, with no significant differences between patient characteristics. The tumor sensitivities of WL, FL, and combination in Group A was 71.9%, 77.1%, 90.5%, respectively, while in Group S, these were 71.5%, 92.2%, 96.1%, respectively. Group S had significantly higher sensitivity of FL and combination than Group A, as well as higher detection of carcinoma in situ lesions. CONCLUSION: Both endoscopic systems had improved sensitivity with PDD-assistance versus WL only, with Group S having higher sensitivity. Differences in the quality of endoscopic equipment may influence the differences in treatment results with PDD-assisted TURBT across institutions.

Favorable Response of Pembrolizumab as Second-Line Therapy for Advanced Urothelial Carcinoma with Only Small Lesions to not be Considered Measurable by RECIST.

PURPOSE: Pembrolizumab is currently considered the standard second-line treatment for advanced urothelial carcinoma (UC). This study aimed to investigate the efficacy and safety of pembrolizumab in patients with advanced UC in real-world data, which is not well-reported. MATERIALS AND METHODS: The study included 97 patients with advanced UC whose lesions were classified according to the Response Evaluation Criteria in Solid Tumors (RECIST). The median age was 73 years. Nineteen patients (20%) with performance status (PS) 2-4 were included. The percentages of liver, lung, bone, and lymph node metastasis were 18%, 27%, 19%, and 76%, respectively. The efficacy, safety, and risk factors for prognosis were evaluated for patients with and without measurable lesions. RESULTS: The best response was complete response in nine patients (9%) and partial response in 16 patients (17%). The median progression-free survival and overall survival were 3.7 months (95% confidence interval [CI]: 2.8-4.7) and 11.8 months (95% CI: 6.7-17.0), respectively. Twenty-one (22%) patients had no measurable lesions per RECIST. In univariate and multivariate analysis, PS 2-4 and lesions by RECIST were identified as factors associated with short overall survival (OS). The median OS of 18.3 months in patients without lesions by RECIST was significantly longer than the median OS of 6.7 months in patients with lesions by RECIST (p = .012). CONCLUSION: We demonstrated that good PS 0-1 and no measurable lesions, especially small lesions, by RECIST were favorable prognostic factors in patients with advanced UC treated by pembrolizumab.

Blood Cell Count Biomarkers Predicting Efficacy of Pembrolizumab as Second-line Therapy for Advanced Urothelial Carcinoma.

BACKGROUND/AIM: To investigate the blood markers for predicting pembrolizumab efficacy in advanced urothelial carcinoma (UC). PATIENTS AND METHODS: This study included 91 advanced UC patients. The relationship between prognosis and markers from peripheral blood cell counts, including the neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), monocyte-lymphocyte ratio (MLR), and systemic inflammation response index (SIRI=monocytes × neutrophils/lymphocytes), was evaluated. RESULTS: Multivariate analysis indicated that pretreatment NLR and the 1-month-change NLR were both significantly associated with overall survival (OS) after pembrolizumab initiation. When the patients were divided into four groups according to calculated cutoffs using Cox proportional hazard model, the pretreatment NLR <2.9 and 1-month change NLR <+43% groups had a significantly better OS than the pretreatment NLR ≥2.9 and 1-month-change NLR ≥+43% groups. CONCLUSION: NLR, MLR, PLR and SIRI before pembrolizumab and 1-month-change NLR in advanced UC correlated with OS after pembrolizumab treatment.

Kinetic exclusion assay of monoclonal antibody affinity to the membrane protein Roundabout 1 displayed on baculovirus.

The reliable assessment of monoclonal antibody (mAb) affinity against membrane proteins in vivo is a major issue in the development of cancer therapeutics. We describe here a simple and highly sensitive method for the evaluation of mAbs against membrane proteins by means of a kinetic exclusion assay (KinExA) in combination with our previously developed membrane protein display system using budded baculovirus (BV). In our BV display system, the membrane proteins are displayed on the viral surface in their native form. The BVs on which the liver cancer antigen Roundabout 1 (Robo1) was displayed were adsorbed onto magnetic beads without fixative (BV beads). The dissociation constant (Kd, ∼10(-11) M) that was measured on the Robo1 expressed BV beads correlated well with the value from a whole cell assay (the coefficient of determination, R(2) = 0.998) but not with the value for the soluble extracellular domains of Robo1 (R(2) = 0.834). These results suggest that the BV-KinExA method described here provides a suitably accurate Kd evaluation of mAbs against proteins on the cell surface.

Protective effect of the long pentraxin PTX3 against histone-mediated endothelial cell cytotoxicity in sepsis.

Pentraxin 3 (PTX3), a member of the long pentraxin subfamily within the family of pentraxins, is a soluble pattern recognition molecule that functions in the innate immune system. Innate immunity affords the infected host protection against sepsis, a potentially life-threatening inflammatory response to infection. Extracellular histones are considered to be the main cause of septic death because of their cytotoxic effect on endothelial cells, which makes them a potential therapeutic target. We found that PTX3 interacted with histones to form coaggregates, which depended on polyvalent interactions and disorder in the secondary structure of PTX3. PTX3 exerted a protective effect, both in vitro and in vivo, against histone-mediated cytotoxicity toward endothelial cells. Additionally, the intraperitoneal administration of PTX3 reduced mortality in mouse models of sepsis. The amino-terminal domain of PTX3, which was required for coaggregation with histones, was sufficient to protect against cytotoxicity. Our results suggest that the host-protective effects of PTX3 in sepsis are a result of its coaggregation with histones rather than its ability to mediate pattern recognition. This long pentraxin-specific effect provides a potential basis for the treatment of sepsis directed at protecting cells from the toxic effects of extracellular histones.

Functional reconstitution of olfactory receptor complex on baculovirus.

Despite that recent progress in genomics has elucidated the genomic structure of the olfactory receptors (ORs), most of them are still orphan receptors. The low expression level of ORs in heterologous cells has hampered many attempts to establish cell biological OR assay systems. Recently, we demonstrated that certain G protein-coupled receptors, such as the leukotriene B4 receptor or the dopamine D1 receptor, were efficiently reconstituted on baculovirus budding from infected Sf9 cells. The budded virus (BV) was shown to be mostly free of exogenous proteins other than those related to viral infection, resulting in low-noise assay conditions. Taking advantage of these conditions, we attempted to reconstitute OR complexes on BV. Sf9 cells were coinfected with recombinant baculoviruses harboring the cDNAs encoding adenylyl cyclase, trimeric G-protein, and the receptor: mOR-EG or S6. The coexpression of these proteins was detected by western blot, and the agonist- or antagonist-dependent receptor response was confirmed using ligand-dependent cyclic AMP production. These results demonstrated the successful reconstitution of functional OR complex on BV. Additionally, the expression of OR8B3 on BV, one of human orphan ORs, was also confirmed. This BV expression system is expected to be a highly effective tool for screening unknown ligands for ORs.

Viral envelope protein gp64 transgenic mouse facilitates the generation of monoclonal antibodies against exogenous membrane proteins displayed on baculovirus.

We have been investigating the functional display of multipass membrane protein such as transporter or G-protein coupled receptor on the budded baculovirus (BV). We tested the use of a viral envelope protein gp64 transgenic mouse for the direct immunization of these membrane proteins displayed on BVs. The gp64 transgenic mice showed only a weak response to virus compared to wild type BALB/c mice. Immunizing gp64 transgenic mice with the BV expressing peptide transporter PepT1, we obtained 47 monoclonal antibodies (mAbs). These mAbs were specific to the PepT1 on the pancreatic cancer cells AsPC-1 by fluorocytometric analysis and exhibited antibody-dependent cellular cytotoxicity or complement-dependent cytotoxicity to AsPC-1. We also generated 7 mAbs by immunizing gp64 transgenic mice on a CCR2-deficient background with the BV expressing chemokine receptor CCR2 together with partially purified CCR2. These mAbs possessed specific binding to CCR2 in CHO cells on fluorocytometric analysis, and exhibited neutralizing activities for ligand-dependent inhibition of cyclic AMP production. This method provides a powerful tool for the generation of therapeutic/diagnostic mAbs against membrane proteins.

Three-dimensional structure of the gamma-secretase complex.

Gamma-secretase belongs to an atypical class of aspartic proteases that hydrolyzes peptide bonds within the transmembrane domain of substrates, including amyloid-beta precursor protein and Notch. gamma-Secretase is comprised of presenilin, nicastrin, APH-1, and PEN-2 which form a large multimeric membrane protein complex, the three-dimensional structure of which is unknown. To gain insight into the structure of this complex enzyme, we purified functional gamma-secretase complex reconstituted in Sf9 cells and analyzed it using negative stain electron microscopy and 3D reconstruction techniques. Analysis of 2341 negatively stained particle images resulted in the three-dimensional representation of gamma-secretase at a resolution of 48 angstroms. The structure occupies a volume of 560 x 320 x 240 angstroms and resembles a flat heart comprised of two oppositely faced, dimpled domains. A low density space containing multiple pores resides between the domains. Some of the dimples in the putative transmembrane region may house the catalytic site. The large dimensions are consistent with the observation that gamma-secretase activity resides within a high molecular weight complex.

Selective reconstitution and recovery of functional gamma-secretase complex on budded baculovirus particles.

In vitro reconstitution of functions of membrane proteins is often hampered by aggregation, misfolding, or lack of post-translational modifications of the proteins attributable to overexpression. To overcome this technical obstacle, we have developed a method to express multimeric integral membrane proteins in extracellular (budded) baculovirus particles that are released from Sf9 cells co-infected with multiple transmembrane proteins. We applied this method to the reconstitution of gamma-secretase, a membrane protease complex that catalyzes the intramembrane cleavage of beta-amyloid precursor protein to release Abeta peptides, the major component of amyloid deposits in Alzheimer brains as well as of Notch. When we co-infected Sf9 cells with human presenilin 1 (PS1), nicastrin, APH-1a, and PEN-2, a high-molecular-weight membrane protein complex that contained PS1 exclusively in its fragment form associated with three other cofactor proteins was reconstituted and recovered in a highly gamma-secretase-active state in budded virus particles, whereas nonfunctional PS1 holoproteins massively contaminated the parental Sf9 cell membranes. The relative gamma-secretase activity (per molar PS1 fragments) was concentrated by approximately 2.5 fold in budded virus particles compared with that in Sf9 membranes. The budded baculovirus system will facilitate structural and functional analyses of gamma-secretase, as well as screening of its binding molecules or inhibitors, and will also provide a versatile methodology for the characterization of a variety of membrane protein complexes.

A novel method for viral display of ER membrane proteins on budded baculovirus.

The baculovirus expression system has been used to express large quantities of various proteins, including membrane receptors. Here, we reveal a novel property of this expression system to be that certain membrane proteins can be displayed on the budded virus itself. We introduced the genes encoding sterol regulatory element-binding protein-2 (SREBP-2) or SREBP cleavage-activating protein (SCAP), important integral membrane proteins of the endoplasmic reticulum (ER) and/or the Golgi apparatus related to cellular cholesterol regulation, into a baculovirus vector. When insect cells were infected with SREBP-2 or SCAP recombinant viruses, it was found that these ER membrane proteins appeared on the budded baculovirus in addition to the host cell membrane fraction. Compared to proteins expressed on the cell membrane, membrane proteins displayed on virus exhibited both less aggregation and less degradation upon immunoblotting. Using this viral displayed SCAP as the screening antigen, we then generated a new monoclonal antibody specific against SCAP, which was useful for immunological localization studies. This system, which takes advantage of the viral display of membrane proteins, should prove to be a powerful additional tool for postgenomic protein analysis.

A combinatorial G protein-coupled receptor reconstitution system on budded baculovirus. Evidence for Galpha and Galphao coupling to a human leukotriene B4 receptor.

To investigate the coupling selectivity of G proteins and G protein-coupled receptors (GPCRs), we developed a reconstitution system made up of GPCR and heterotrimeric G proteins on extracellular baculovirus particles (budded virus (BV)). BV released from Sf9 cells infected with a recombinant baculovirus coding for human leukotriene B4 receptor (BLT1) cDNA exhibited a high level of BLT1 expression (27.3 pmol/mg of protein) and specific [3H]leukotriene B4 binding activity (Kd = 3.67 nm). The apparent low affinity of the expressed BLT1 is thought to be due to relative non-availability of the Galphai isoform, which couples to BLT1, in BV. Co-infection of heterotrimeric G protein recombinant viruses led to co-expression of BLT1 and G protein subunits on BV. A guanosine-5'-(beta,gamma-imido)triphosphate-sensitive, high affinity ligand binding was observed in the BLT1 BV co-expressing Galphai1beta1gamma2 (Kd = 0.17 nm). A relatively large amount of high affinity receptor protein was recovered in the co-expressing BV fraction (6.81 pmol/mg of protein). A combination of BLT1 and Galphai1 without Gbeta1gamma2 did not exhibit high affinity ligand binding on BV, indicating the low background environment for the GPCR-G protein coupling in this BV reconstitution system. To test other G proteins for coupling, various Galpha subunits were combinatorially expressed in BV with BLT1 and Gbeta1gamma2. The BLT1 BV co-expressing GalphaoAbeta1gamma2 exhibited a comparably high affinity ligand binding as well as ligand-stimulated guanosine 5'-3-O-(thio)triphosphate binding to Galphai1beta1gamma2. Co-expression of other Galpha isoforms such as Galphas, Galpha11, Galpha14, Galpha16, Galpha12, or Galpha13 did not exhibit any significant effects on ligand binding affinity in this system. These results reveal that BLT1 and coupled trimeric G proteins were functionally reconstituted on BV and that Galphao as well as Galphai couples to BLT1. This expression system should prove highly useful for pharmacological characterization, biosensor chip applications, and also drug discovery directed at highly important targets of the membrane receptor proteins.