Engineering CD3/CD137 Dual Specificity into a DLL3-Targeted T-Cell Engager Enhances T-Cell Infiltration and Efficacy against Small-Cell Lung Cancer.

Small-cell lung cancer (SCLC) is an aggressive cancer for which immune checkpoint inhibitors (ICI) have had only limited success. Bispecific T-cell engagers are promising therapeutic alternatives for ICI-resistant tumors, but not all patients with SCLC are responsive. Herein, to integrate CD137 costimulatory function into a T-cell engager format and thereby augment therapeutic efficacy, we generated a CD3/CD137 dual-specific Fab and engineered a DLL3-targeted trispecific antibody (DLL3 trispecific). The CD3/CD137 dual-specific Fab was generated to competitively bind to CD3 and CD137 to prevent DLL3-independent cross-linking of CD3 and CD137, which could lead to systemic T-cell activation. We demonstrated that DLL3 trispecific induced better tumor growth control and a marked increase in the number of intratumoral T cells compared with a conventional DLL3-targeted bispecific T-cell engager. These findings suggest that DLL3 trispecific can exert potent efficacy by inducing concurrent CD137 costimulation and provide a promising therapeutic option for SCLC.

Pachychoroid-phenotype effects on 5-year visual outcomes of anti-VEGF monotherapy in polypoidal choroidal vasculopathy.

PURPOSE: To investigate whether the efficacy of anti-vascular endothelial growth factor (VEGF) monotherapy for polypoidal choroidal vasculopathy (PCV) differs between pachychoroid and non-pachychoroid phenotypes in the long term. METHODS: This retrospective longitudinal study included 115 treatment-naïve eyes in 115 consecutive patients with symptomatic PCV who were treated with anti-VEGF monotherapy and were followed up for 5 years. Eligible eyes were assigned to either a pachy-PCV group, with a pachychoroid phenotype, or a non-pachy-PCV group, without a pachychoroid phenotype. Best-corrected visual acuity (BCVA) and other parameters over a 5-year period were compared between the groups. RESULTS: Forty-eight eyes and 67 eyes were classified into the pachy-PCV and non-pachy-PCV groups respectively. Baseline and 5-year BCVA (logarithm of the minimum angle of resolution) were 0.19 ± 0.20 and 0.16 ± 0.28 in the pachy-PCV group, respectively, and 0.25 ± 0.26 and 0.26 ± 0.36 in the non-pachy-PCV group respectively. BCVA did not change significantly in either group (p = 0.18 and 0.08 respectively). BCVA did not differ between the groups at any observation time-point. Subfoveal choroidal thickness (SFCT) at baseline and at 5 years was significantly higher in the pachy-PCV group than in the non-pachy-PCV group (both p < 0.001); however, the mean rate of decrease in SFCT did not differ in either group over the 5-year period (22% vs. 23%, p = 0.81). CONCLUSION: Our findings suggest that anti-VEGF monotherapy was similarly effective for pachychoroid- and non-pachychoroid-phenotype eyes with PCV, for at least 5 years, although further studies are required.

GH-induced LH hyporesponsiveness as a potential mechanism for hypogonadism in male patients with acromegaly.

Male patients with acromegaly frequently have hypogonadism. However, whether excess GH affects gonadal function remains unclear. We retrospectively compared clinical features affecting total testosterone (TT) and free testosterone (FT) levels between 112 male patients with acromegaly and 100 male patients with non-functioning pituitary adenoma (NFPA) without hyperprolactinemia. Median maximum tumor diameter (14.4 vs. 26.5 mm) and suprasellar extension rate (33 vs. 100%) were lower in acromegaly, but LH, FSH, TT, and FT were not significantly different. In acromegaly, TT was less than 300 ng/dL in 57%, and FT was below the age-specific reference range in 77%. TT and FT were negatively correlated with GH, IGF-1, and the tumor size, and positively correlated with LH. In NFPA, they were positively correlated with IGF-1, LH, FSH, ACTH, cortisol, and free T4, reflecting hypopituitarism. Multiple regression analysis showed that TT and FT had the strongest correlation with GH in acromegaly, and with LH in NFPA. Surgical remission was achieved in 87.5% of 56 follow-up patients with acromegaly. TT and FT increased in 80.4 and 87.5%, respectively, with a significant increase in LH. In acromegaly, the degree of postoperative increase in TT(FT) correlated with the fold increase of TT(FT)/LH ratio, a potential parameter of LH responsiveness, but not with fold increase of LH, whereas in NFPA it correlated with both. These results suggest that excessive GH is the most relevant factor for hypogonadism in male acromegaly, and may cause impaired LH responsiveness as well as the suppression of LH secretion.

Expansion of mouse primitive hematopoietic cells in three-dimensional cultures on chemically fixed stromal cell layers.

To establish a practical and convenient method to expand hematopoietic cells (HCs), we applied chemically-fixed stromal cell layers formed within three-dimensional (3D) scaffolds to feeder of HC cultures. The HCs were expanded using two successive cultures. First, stromal cells were cultured within porous polymer scaffolds and formed tissue-engineered constructs (TECs); the scaffolds containing stromal cells, were fixed using aldehyde (formaldehyde or glutaraldehyde) or organic solvents (acetone, methanol or ethanol). Second, mouse fetal liver cells (FLCs), as a source of HCs, were cultured on the TECs for 2 weeks, and the effects of fixative solutions on expansion of primitive HCs (c-kit+ and CD34+ cells) were examined. In the cultures on aldehyde-fixed TECs, primitive HCs were expanded 2.5- to 5.1-fold in the cultures on TECs fixed with glutaraldehyde, whereas no expansions were detected in those fixed with formaldehyde. However, we achieved expansion of primitive HCs > fivefold in the cultures using TECs fixed with organic solvents. Among these solvents, the highest expansions-of roughly tenfold-were obtained using acetone fixation. Ethanol-fixed TECs also supported the expansion of the primitive HCs well (6.6- to 8.0-fold). In addition to these sufficient expansions, the procedure and storage of fixed TECs is fairly easy. Thus, HC expansion on chemically-fixed TECs may be a practical method for expanding primitive HCs.

Landiolol hydrochloride for prevention of atrial fibrillation during esophagectomy: a randomized controlled trial.

INTRODUCTION: Landiolol hydrochloride reduces the incidence of perioperative atrial fibrillation (AF) in cardiac surgery; however, little evidence is available regarding its effects in other types of surgery, including esophagectomy. We assessed the hypothesis that landiolol reduces perioperative AF and other complications associated with esophagectomy. METHODS: This single-center, randomized, double-blind, parallel-group study enrolled patients scheduled for esophagectomy. Patients were divided into those given landiolol at 3 µg/kg/min or placebo for 24 h. The primary outcome was the proportion of patients who developed AF within 96 h starting at 9:00 AM on the day of surgery. The secondary outcomes were the proportion of patients whose AF appeared within 24 h, other complications based on the Clavien-Dindo classification, and the intensive care unit and hospital stays. RESULTS: Despite early study termination, 80 patients were screened, and 56 were enrolled (28/group) from September 2016 to June 2018. AF occurred within 96 h of surgery in six (21.4%) patients in the landiolol group and five (17.9%) patients in the placebo group (odds ratio, 1.26; 95% confidence interval, 0.33-4.7) and within 24 h of surgery in three (10.7%) patients in the landiolol group and two (7.1%) patients in the placebo group. There were no significant differences in the incidence of complications or in the number of intensive care unit or hospital stays between the groups. CONCLUSION: Although our small sample size prevents definitive conclusions, landiolol might not reduce the occurrence of AF or other complications. TRIAL REGISTRATION: UMIN, UMIN000024040. Registered 13 September 2016, http://www.umin.ac.jp/ctr/index/htm.

Controlled conductivity at low pH in Protein L chromatography enables separation of bispecific and other antibody formats by their binding valency.

The complex molecular formats of recent therapeutic antibodies, including bispecific antibodies, antibody fragments, and other fusion proteins, makes the task of purifying the desired molecules in a limited number of purification steps more and more challenging. Manufacturing these complicated biologics can be substantially improved in the affinity capture stage if the simple bind-and-elute mode is accompanied by targeted removal of the impurities, such as mis-paired antibodies and oligomers or aggregates. Here, we report a method, based on the binding valency to Protein L resin, of separating proteins during the elution step by simply controlling the conductivity at low pH. We show that the method efficiently separated targeted antibodies from mis-paired and aggregated species. Notably, the number of Protein L binding sites can be built into the molecule by design to facilitate the purification. This method may be useful for purifying various antibody formats at laboratory and manufacturing scales.

Expansion of mouse hematopoietic stem/progenitor cells in three-dimensional cocultures on growth-suppressed stromal cell layer.

With the aim of establishing an effective method to expand hematopoietic stem/progenitor cells for application in hematopoietic stem cell transplantation, we performed ex vivo expansion of hematopoietic stem/progenitor cells derived from mouse fetal liver cells in three-dimensional cocultures with stromal cells. In these cocultures, stromal cells were first cultured within three-dimensional scaffolds to form stromal layers and then fetal liver cells containing hematopoietic cells were seeded on these scaffolds to expand the hematopoietic cells over the 2 weeks of coculture in a serum-containing medium without the addition of cytokines. Prior to coculture, stromal cell growth was suppressed by treatment with the DNA synthesis inhibitor mitomycin C, and its effect on hematopoietic stem/progenitor cell expansion was compared with that in control cocultures in which fetal liver cells were cocultured with three-dimensional freeze-thawed stromal cells. After coculture with mitomycin C-treated stromal cells, we achieved a several-fold expansion of the primitive hematopoietic cells (c-kit+ hematopoietic progenitor cells >7.8-fold, and CD34+ hematopoietic stem/progenitor cells >3.5-fold). Compared with control cocultures, expansion of hematopoietic stem/progenitor cells tended to be lower, although that of hematopoietic progenitor cells was comparable. Thus, our results suggest that three-dimensional freeze-thawed stromal cells have higher potential to expand hematopoietic stem/progenitor cells compared with mitomycin C-treated stromal cells.

Mutational analysis of patients with FGF23-related hypophosphatemic rickets.

OBJECTIVE: X-linked hypophosphatemic rickets (XLHR) caused by mutations in the PHEX gene is considered to be the most frequent cause of fibroblast growth factor 23 (FGF23)-related congenital hypophosphatemic rickets. In previous studies, mutations in the PHEX gene were detected in 60-70% of patients with clinical diagnoses of XLHR. This leads to the question whether current screening methods for mutations in the PHEX gene are inadequate or whether there is a substantial number of patients with other genetic causes of hypophosphatemic rickets. We conducted a genetic analysis of patients with FGF23-related hypophosphatemic rickets to clarify their etiology and evaluate the prevalence of XLHR among this group. DESIGN AND METHODS: We studied 27 patients with familial and sporadic congenital hypophosphatemic rickets in whom serum FGF23 was above 30 pg/ml using an assay for the full-length protein. Exons and exon-intron junctions of genomic DNA of causative genes for FGF23-related hypophosphatemic rickets were sequenced. PHEX mRNA from peripheral blood was analyzed in some patients. RESULTS: Direct sequencing of genomic DNA identified 11 novel and four known mutations in the PHEX gene. Additionally, there was a large PHEX gene deletion in one case and abnormal PHEX mRNA splicing in another. In summary, 26 patients (96%) had XLHR and one patient had autosomal recessive hypophosphatemic rickets 2. CONCLUSIONS: XLHR is by far the most prevalent cause of FGF23-related hypophosphatemic rickets. We propose that analysis of PHEX mRNA from peripheral blood would be appropriate for the first screening step in determining the etiology of FGF23-related hypophosphatemic rickets.

C-terminal mutations destabilize SIL1/BAP and can cause Marinesco-Sjögren syndrome.

Marinesco-Sjögren syndrome (MSS) is an autosomal recessive, neurodegenerative, multisystem disorder characterized by severe phenotypes developing in infancy. Recently, mutations in the endoplasmic reticulum (ER)-associated co-chaperone SIL1/BAP were identified to be the major cause of MSS. SIL1 acts as a nucleotide exchange factor for BiP, the ER Hsp70 orthologue, which plays an essential role in the folding and assembly of nascent polypeptide chains in the ER. SIL1 facilitates the release of BiP from unfolded protein substrates, enabling the subsequent folding and transport of the protein. Although most mutations leading to MSS result in deletion of the majority of the protein, three separate mutations have been identified that disrupt only the last five or six amino acids of the protein, which were assumed to encode a divergent ER retention motif. This study presents an in depth analysis of two of these mutants and reveals that the phenotype in the affected individuals is not likely to be due to depletion of SIL1 from the ER via secretion. Instead, our analyses show that the mutant proteins are particularly unstable and either form large aggregates in the ER or are rapidly degraded via the proteasome. In agreement with our findings, homology modeling suggests that the very C-terminal residues of SIL1 play a role in its structural integrity rather than its localization. These new insights might be a first step toward a possible pharmacological treatment of certain types of MSS by specifically stabilizing the mutant SIL1 protein.

Fibroblast growth factor 23 as a phosphotropic hormone and beyond.

Fibroblast growth factor 23 (FGF23) is produced by bone and reduces serum phosphate by inhibiting proximal tubular phosphate reabsorption and intestinal phosphate absorption. Excess actions of FGF23 cause several kinds of hypophosphatemic rickets/osteomalacia while deficient actions of FGF23 result in hyperphosphatemic tumoral calcinosis. In addition, FGF23 has been shown to prevent the development of hyperphosphatemia during the progression of chronic kidney disease-mineral and bone disorder. Epidemiological studies have indicated that high FGF23 levels are associated with unfavorable events including higher mortality, cardiovascular events, progression of CKD and fracture; however, these associations are not observed unequivocally and it is not evident why they are present. While FGF23 has been shown to be a hormone that regulates phosphate metabolism, it remains to be established whether FGF23 has roles other than regulating mineral homeostasis.

A patient with hypophosphatemic rickets and ossification of posterior longitudinal ligament caused by a novel homozygous mutation in ENPP1 gene.

X-linked hypophosphatemic rickets/osteomalacia (XLH), autosomal dominant hypophosphatemic rickets/osteomalacia (ADHR) and autosomal recessive hypophosphatemic rickets/osteomalacia (ARHR1 or ARHR2) are hereditary fibroblast growth factor 23 (FGF23)-related hypophosphatemic rickets showing similar clinical features. We here show a patient with hypophosphatemic rickets and widespread ossification of posterior longitudinal ligament (OPLL). The proband is a 62-year-old female. Her parents are first cousins and showed no signs of rickets or osteomalacia. She showed hypophosphatemic rickets with elevated FGF23 level and had been clinically considered to be suffering from XLH. However, direct sequencing of all coding exons and exon-intron junctions of phosphate regulating gene with homologies to endopeptidases on the X chromosome (PHEX), FGF23 and dentin matrix protein 1 (DMP1) genes, responsible genes for XLH, ADHR and ARHR1, respectively, showed no mutation. A novel homozygous splice donor site mutation was found at the exon-intron junction of exon 21 of ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) gene responsible for ARHR2 (IVS21+1_3(GTA>CACC)). Subsequent analysis of mRNA revealed that this mutation caused skipping of exon 21 which created a premature stop codon in exon 22. These results indicate that genetic analysis is mandatory for the correct diagnosis of hereditary FGF23-related hypophosphatemic rickets. Because Enpp1 knockout mouse is a model of OPLL, this case also suggests that OPLL is associated with ARHR2.

Ubiquitylation of an ERAD substrate occurs on multiple types of amino acids.

Any protein synthesized in the secretory pathway has the potential to misfold and would need to be recognized and ubiquitylated for degradation. This is astounding, since only a few ERAD-specific E3 ligases have been identified. To begin to understand substrate recognition, we wished to map the ubiquitylation sites on the NS-1 nonsecreted immunoglobulin light chain, which is an ERAD substrate. Ubiquitin is usually attached to lysine residues and less frequently to the N terminus of proteins. In addition, several viral E3s have been identified that attach ubiquitin to cysteine or serine/threonine residues. Mutation of lysines, serines, and threonines in the NS-1 variable region was necessary to significantly reduce ubiquitylation and stabilize the protein. The Hrd1 E3 ligase was required to modify all three amino acids. Our studies argue that ubiquitylation of ER proteins relies on very different mechanisms of recognition and modification than those used to regulate biological processes.

Stimulation of DNA Glycosylase Activities by XPC Protein Complex: Roles of Protein-Protein Interactions.

We showed that XPC complex, which is a DNA damage detector for nucleotide excision repair, stimulates activity of thymine DNA glycosylase (TDG) that initiates base excision repair. XPC appeared to facilitate the enzymatic turnover of TDG by promoting displacement from its own product abasic site, although the precise mechanism underlying this stimulation has not been clarified. Here we show that XPC has only marginal effects on the activity of E. coli TDG homolog (EcMUG), which remains bound to the abasic site like human TDG but does not significantly interacts with XPC. On the contrary, XPC significantly stimulates the activities of sumoylated TDG and SMUG1, both of which exhibit quite different enzymatic kinetics from unmodified TDG but interact with XPC. These results point to importance of physical interactions for stimulation of DNA glycosylases by XPC and have implications in the molecular mechanisms underlying mutagenesis and carcinogenesis in XP-C patients.

Tumor-induced osteomalacia associated with a maxillofacial tumor producing fibroblast growth factor 23: report of a case and review of the literature.

Tumor-induced osteomalacia (TIO) is a rare acquired paraneoplastic disease characterized by renal phosphate wasting and hypophosphatemia. Recently, it was reported that tumors associated with TIO produce fibroblast growth factor (FGF) 23, identified as the last member of the FGF family and of which excessive action causes several hypophosphatemic diseases whereas deficient FGF23 activity results in hyperphosphatemic tumoral calcinosis. In this case, although it was difficult to locate the associated tumor, an abnormal mass in the left maxilla was detected by imaging. The tumor was removed by partial resection of the left maxillary alveolar region. Thereafter, serum level of FGF23 rapidly decreased, hypophosphatemia improved, and the clinical symptoms greatly improved. Histopathologic diagnosis of the tumor was phosphaturic mesenchymal tumor, mixed connective tissue variant. Immunohistochemical findings confirmed that the removed tumor produced FGF23. These results indicate that development of osteomalacia in this patient was related to the maxillary tumor, which overexpressed FGF23.

pERp1 is significantly up-regulated during plasma cell differentiation and contributes to the oxidative folding of immunoglobulin.

Plasma cells can synthesize and secrete thousands of Ig molecules per second, which are folded and assembled in the endoplasmic reticulum (ER) and are likely to place unusually high demands on the resident chaperones and folding enzymes. We have discovered a new resident ER protein (pERp1) that is a component of the BiP chaperone complex. PERp1 is substantially up-regulated during B to plasma cell differentiation and can be induced in B cell lines by some UPR activators, arguing that it represents a potentially new class of conditional UPR targets. In LPS-stimulated murine splenocytes, pERp1 interacted covalently via a disulfide bond with IgM monomers and noncovalently with other Ig assembly intermediates. Knockdown and overexpression experiments revealed that pERp1 promoted correct oxidative folding of Ig heavy chains and prevented off-pathway assembly intermediates. Although pERp1 has no homology with known chaperones or folding enzymes, it possesses a thioredoxin-like active site motif (CXXC), which is the signature of oxidoreductases. Mutation of this sequence did not affect its in vivo activity, suggesting that pERp1 is either a unique type of oxidoreductase or a previously unidentified class of molecular chaperone that is dedicated to enhancing the oxidative folding of Ig precursors.

[Clinical aspect of recent progress in phosphate metabolism. The pathophysiology of diseases caused by aberrant actions of FGF23].

FGF23 is a humoral factor that is produced by osteocytes and reduces serum phosphate and 1,25-dihydroxyvitamin D levels by binding to a complex comprised of Klotho and some FGF receptor in kidney. After the identification of FGF23, it has been shown that aberrant actions of FGF23 underlie several diseases. While several kinds of hypophosphatemic rickets/osteomalacia are caused by excess actions of FGF23, deficient actions of FGF23 result in hyperphosphatemic tumoral calcinosis.

Hypophosphatemia induced by intravenous administration of saccharated ferric oxide: another form of FGF23-related hypophosphatemia.

Fibroblast growth factor 23 (FGF23) is a humoral factor that is produced by osteocytes and regulates phosphate and vitamin D metabolism. Several hypophosphatemic diseases including X-linked, autosomal dominant and autosomal recessive hypophosphatemic rickets/osteomalacia and tumor-induced rickets/osteomalacia are caused by excess actions of FGF23. These diseases are characterized by hypophosphatemia associated with impaired proximal tubular phosphate reabsorption and inappropriately low serum 1,25-dihydroxyvitamin D [1,25(OH)(2)D] levels for hypophosphatemia. Saccharated ferric oxide is widely used in Japan for iron-deficiency anemia. While it has been shown that saccharated ferric oxide induces hypophosphatemic osteomalacia, the mechanism of this hypophosphatemia remains to be clarified. We here describe three hypophosphatemic patients caused by intravenous administration of saccharated ferric oxide. Hypophosphatemia in these patients were associated with impaired renal tubular phosphate reabsorption, rather low serum 1,25(OH)(2)D and high FGF23 levels. All these biochemical features improved by the cessation of saccharated ferric oxide. These results indicate that hypophosphatemia caused by saccharated ferric oxide is another form of FGF23-related hypophosphatemia.

Organization of the functions and components of the endoplasmic reticulum.

The endoplasmic reticulum is the site of entry into the secretory pathway and represents a major and particularly crowded site of protein biosynthesis. In addition to the complexity of protein folding in any organelle, the ER environment poses further dangers and constraints to the process. A quality control apparatus exists to monitor the maturation of proteins in the ER. Nascent polypeptide chains are specifically prevented from traveling further along the secretory pathway until they have completed their folding or assembly. Proteins that cannot achieve a proper conformation are recognized and removed from the ER for degradation by the 26S proteasome. Finally, the homeostasis of the ER is vigilantly monitored and changes that impinge upon the proper maturation of proteins in this organelle lead to the activation of a signal transduction cascade that serves to restore balance to the ER. Recent studies suggest that some of these diverse functions may be achieved due to the organization of the ER into functional and perhaps even physical sub-domains.

Nucleotide excision repair of 5-formyluracil in vitro is enhanced by the presence of mismatched bases.

5-Formyluracil (fU) is a major thymine lesion produced by reactive oxygen radicals and photosensitized oxidation. Although this residue is a potentially mutagenic lesion and is removed by several base excision repair enzymes, it is unknown whether fU is the substrate of nucleotide excision repair (NER). Here, we analyzed the binding specificity of XPC-HR23B, which initiates NER, and cell-free NER activity on fU opposite four different bases. The result of the gel mobility shift assay showed that XPC-HR23B binds the fU-containing substrates in the following order: fU:C >> fU:T > fU:G > fU:A. Furthermore, in the presence of XPC-HR23B, the dual incision activity was the same as the order of the binding affinity of XPC-HR23B to fU. Therefore, it is concluded that even fU, regarded as a shape mimic of thymine, can be recognized as a substrate of NER incision, and the efficiency depends on instability of the base pair.

Xeroderma pigmentosum group C protein interacts physically and functionally with thymine DNA glycosylase.

The XPC-HR23B complex recognizes various helix-distorting lesions in DNA and initiates global genome nucleotide excision repair. Here we describe a novel functional interaction between XPC-HR23B and thymine DNA glycosylase (TDG), which initiates base excision repair (BER) of G/T mismatches generated by spontaneous deamination of 5-methylcytosine. XPC-HR23B stimulated TDG activity by promoting the release of TDG from abasic sites that result from the excision of mismatched T bases. In the presence of AP endonuclease (APE), XPC-HR23B had an additive effect on the enzymatic turnover of TDG without significantly inhibiting the subsequent action of APE. Our observations suggest that XPC-HR23B may participate in BER of G/T mismatches, thereby contributing to the suppression of spontaneous mutations that may be one of the contributory factors for the promotion of carcinogenesis in xeroderma pigmentosum genetic complementation group C patients.