Neuro-regenerative behavior of adipose-derived stem cells in aligned collagen I hydrogels.

Peripheral nerve injuries persist as a major clinical issue facing the US population and can be caused by stretch, laceration, or crush injuries. Small nerve gaps are simple to treat, and the nerve stumps can be reattached with sutures. In longer nerve gaps, traditional treatment options consist of autografts, hollow nerve guidance conduits, and, more recently, manufactured fibrous scaffolds. These manufactured scaffolds often incorporate stem cells, growth factors, and/or extracellular matrix (ECM) proteins to better mimic the native environment but can have issues with homogenous cell distribution or uniformly oriented neurite outgrowth in scaffolds without fibrous alignment. Here, we utilize a custom device to fabricate collagen I hydrogels with aligned fibers and encapsulated adipose-derived mesenchymal stem cells (ASCs) for potential use as a peripheral nerve repair graft. Initial results of our scaffold system revealed significantly less cell viability in higher collagen gel concentrations; 3 mg/mL gels showed 84.8 ± 7.3% viable cells, compared to 6 mg/mL gels viability of 76.7 ± 9.5%. Mechanical testing of the 3 mg/mL gels showed a Young's modulus of 6.5 ± 0.8 kPa nearly matching 7.45 kPa known to support Schwann cell migration. Further analysis of scaffolds coupled with stretching in vitro revealed heightened angiogenic and factor secretion, ECM deposition, fiber alignment, and dorsal root ganglia (DRG) neurite outgrowth along the axis of fiber alignment. Our platform serves as an in vitro testbed to assess neuro-regenerative potential of ASCs in aligned collagen fiber scaffolds and may provide guidance on next-generation nerve repair scaffold design.

Preclinical Profile of BYON3521 Predicts an Effective and Safe MET Antibody-Drug Conjugate.

MET, the cell-surface receptor for the hepatocyte growth factor/scatter factor, which is widely overexpressed in various solid cancer types, is an attractive target for the development of antibody-based therapeutics. BYON3521 is a novel site-specifically conjugated duocarmycin-based antibody-drug conjugate (ADC), comprising a humanized cysteine-engineered IgG1 monoclonal antibody with low pmol/L binding affinity towards both human and cynomolgus MET. In vitro studies showed that BYON3521 internalizes efficiently upon MET binding and induces both target- and bystander-mediated cell killing. BYON3521 showed good potency and full efficacy in MET-amplified and high MET-expressing cancer cell lines; in moderate and low MET-expressing cancer cell lines good potencies and partial efficacy were observed. In mouse xenograft models, BYON3521 showed significant antitumor activity upon single-dose administration in multiple non-MET-amplified tumor types with low, moderate, and high MET expression, including complete tumor remissions in models with moderate MET expression. In the repeat-dose Good Laboratory Practice (GLP) safety assessment in cynomolgus monkeys, BYON3521 was well tolerated and based on the observed toxicities and their reversibility, the highest non-severely toxic dose was set at 15 mg/kg. A human pharmacokinetics (PK) model was derived from the PK data from the cynomolgus safety assessments, and the minimal efficacious dose in humans is estimated to be in the range of 3 to 4 mg/kg. In all, our nonclinical data suggests that BYON3521 is a safe ADC with potential for clinical benefit in patients. A first-in-human dose-escalation study is currently ongoing to determine the maximum tolerated dose and recommended dose for expansion (NCT05323045).

The Preclinical Profile of the Duocarmycin-Based HER2-Targeting ADC SYD985 Predicts for Clinical Benefit in Low HER2-Expressing Breast Cancers.

SYD985 is a HER2-targeting antibody-drug conjugate (ADC) based on trastuzumab and vc-seco-DUBA, a cleavable linker-duocarmycin payload. To evaluate the therapeutic potential of this new ADC, mechanistic in vitro studies and in vivo patient-derived xenograft (PDX) studies were conducted to compare SYD985 head-to-head with T-DM1 (Kadcyla), another trastuzumab-based ADC. SYD985 and T-DM1 had similar binding affinities to HER2 and showed similar internalization. In vitro cytotoxicity assays showed similar potencies and efficacies in HER2 3+ cell lines, but in cell lines with low HER2 expression, SYD985 was 3- to 50-fold more potent than T-DM1. In contrast with T-DM1, SYD985 efficiently induced bystander killing in vitro in HER2-negative (HER2 0) cells mixed with HER2 3+, 2+, or 1+ cell lines. At pH conditions relevant for tumors, cathepsin-B cleavage studies showed efficient release of the active toxin by SYD985 but not by T-DM1. These in vitro data suggest that SYD985 might be a more potent ADC in HER2-expressing tumors in vivo, especially in low HER2-expressing and/or in heterogeneous tumors. In line with this, in vivo antitumor studies in breast cancer PDX models showed that SYD985 is very active in HER2 3+, 2+, and 1+ models, whereas T-DM1 only showed significant antitumor activity in HER2 3+ breast cancer PDX models. These properties of SYD985 may enable expansion of the target population to patients who have low HER2-expressing breast cancer, a patient population with still unmet high medical need.

Preclinical profile of the HER2-targeting ADC SYD983/SYD985: introduction of a new duocarmycin-based linker-drug platform.

A linker-drug platform was built on the basis of a cleavable linker-duocarmycin payload for the development of new-generation antibody-drug conjugates (ADC). A leading ADC originating from that platform is SYD983, a HER2-targeting ADC based on trastuzumab. HER2-binding, antibody-dependent cell-mediated cytotoxicity and HER2-mediated internalization are similar for SYD983 as compared with trastuzumab. HER2-expressing cells in vitro are very potently killed by SYD983, but SYD983 is inactive in cells that do not express HER2. SYD983 dose dependently reduces tumor growth in a BT-474 mouse xenograft in vivo. The ADC is stable in human and cynomolgus monkey plasma in vitro but shows relatively poor stability in mouse plasma due to mouse-specific carboxylesterase. SYD983 could be dosed up to 30 mg/kg in cynomolgus monkeys with high exposure, excellent stability in blood, and without severe toxic effects. The monkey safety study showed no SYD983-induced thrombocytopenia and no induction of peripheral sensory neuropathy, both commonly observed in trials and studies with ADCs based on tubulin inhibitors. Finally, to improve homogeneity, SYD983 was further purified by hydrophobic interaction chromatography resulting in an ADC (designated SYD985) predominantly containing DAR2 and DAR4 species. SYD985 showed high antitumor activity in two patient-derived xenograft models of HER2-positive metastatic breast cancers. In conclusion, the data obtained indicate great potential for this new HER2-targeting ADC to become an effective drug for patients with HER2-positive cancers with a favorable safety profile. More generally, this new-generation duocarmycin-based linker-drug technology could be used with other mAbs to serve more indications in oncology.

N-[2-(Pyridin-2-yl)ethyl]-derivatives of methane-, benzene- and toluenesulfonamide: prospective ligands for metal coordination.

The molecular and supramolecular structures are reported of N-[2-(pyridin-2-yl)ethyl]methanesulfonamide, C8H12N2O2S, (I), N-[2-(pyridin-2-yl)ethyl]benzenesulfonamide, C13H14N2O2S, (II), and N-[2-(pyridin-2-yl)ethyl]toluenesulfonamide, C14H16N2O2S, (III). Although (II) and (III) are almost structurally identical, the N(amide)-C(ethyl)-C(ethyl)-C(pyridinyl) torsion angles for (I) and (II) are more closely comparable, with magnitudes of 175.37 (15)° for (I) and 169.04 (19)° for (II). This angle decreases dramatically with an additional methyl group in the para position of the sulfonamide substituent, resulting in a value of 62.9 (2)° for (III). In each of the three compounds there is an N-H...N hydrogen bond between the sulfonamide of one molecule and the pyridine N atom of a neighbor. Compound (I) forms hydrogen-bonded dimers, (II) uses its hydrogen bonding to connect supramolecular layers, and the hydrogen bonding of (III) connects linear chains to form layers. For arene-substituted (II) and (III), the different conformations afforded by the variable dihedral angles promote intermolecular π-π stacking in the benzene-substituted structure (II), but distorted intramolecular T-shaped π-stacking in the toluene-substituted structure (III), with a centroid-to-centroid distance of 4.9296 (10) Å.

Daratumumab, a novel therapeutic human CD38 monoclonal antibody, induces killing of multiple myeloma and other hematological tumors.

CD38, a type II transmembrane glycoprotein highly expressed in hematological malignancies including multiple myeloma (MM), represents a promising target for mAb-based immunotherapy. In this study, we describe the cytotoxic mechanisms of action of daratumumab, a novel, high-affinity, therapeutic human mAb against a unique CD38 epitope. Daratumumab induced potent Ab-dependent cellular cytotoxicity in CD38-expressing lymphoma- and MM-derived cell lines as well as in patient MM cells, both with autologous and allogeneic effector cells. Daratumumab stood out from other CD38 mAbs in its strong ability to induce complement-dependent cytotoxicity in patient MM cells. Importantly, daratumumab-induced Ab-dependent cellular cytotoxicity and complement-dependent cytotoxicity were not affected by the presence of bone marrow stromal cells, indicating that daratumumab can effectively kill MM tumor cells in a tumor-preserving bone marrow microenvironment. In vivo, daratumumab was highly active and interrupted xenograft tumor growth at low dosing. Collectively, our results show the versatility of daratumumab to effectively kill CD38-expressing tumor cells, including patient MM cells, via diverse cytotoxic mechanisms. These findings support clinical development of daratumumab for the treatment of CD38-positive MM tumors.

Asymmetric total synthesis of pyranicin.

The asymmetric total synthesis of pyranicin (1) is reported. The butenolide ring was constructed via an asymmetric alkylation/ring-closing metathesis strategy. The three stereocenters in the left-hand tetrahydropyran ring were installed by sequential chiral auxiliary-mediated aldol reactions. Closure of the tetrahydropyran and fusion of the alkyl backbone were affected via a sequential ring-closing metathesis-cross-metathesis strategy.

Hypertension during pregnancy in South Australia, part 1: pregnancy outcomes.

BACKGROUND: There have been conflicting reports about pregnancy outcome in the hypertensive disorders of pregnancy. The present study was undertaken to examine outcomes using a population database. AIMS: To examine for differences in a range of pregnancy outcomes between three different groups of hypertensive women and normotensive women in South Australia. METHODS: Nine pregnancy outcomes were compared for 70,386 singleton pregnancies in the South Australian perinatal data collection in 1998-2001, consisting of 639 women with pre-existing hypertension, 5356 women with pregnancy hypertension, 448 women with superimposed pre-eclampsia and 63 943 normotensive women. Means for the four groups were calculated for birthweight, gestational age, the baby's and mother's length of stay. The groups were also compared for perinatal deaths with an earlier period, 1991-1997. RESULTS: While all three hypertensive groups had high incidences of induction of labour and emergency Caesarean, only pre-existing hypertension and superimposed pre-eclampsia were significantly associated with elective Caesarean section. All hypertensive groups had increased risks for low birthweight and preterm birth and special and neonatal intensive care. Uncomplicated pre-existing hypertension was not associated with small for gestational age infants, but with preterm delivery between 32 and 36 weeks' gestation. Superimposed pre-eclampsia had the worst prognosis for perinatal and maternal morbidity. While pregnancy hypertension held the intermediate position, it was not associated with an increase in perinatal mortality. The perinatal mortality rate for women with hypertensive disorders in 1998-2001 was significantly lower than that of an earlier period and equivalent to that for normotensive women. CONCLUSIONS: Superimposed pre-eclampsia occurs in approximately 40% of pregnancies of women with pre-existing hypertension and has the most severe outcomes. The hypertensive disorders are associated with high levels of morbidity and intervention, but the high perinatal mortality associated with these disorders has fallen significantly.

Hypertension during pregnancy in South Australia, part 2: risk factors for adverse maternal and/or perinatal outcome - results of multivariable analysis.

OBJECTIVE: To identify factors associated with adverse pregnancy outcomes among women with hypertension during pregnancy. DESIGN: A population-based retrospective multivariable analysis using the South Australian perinatal data collection. METHODS: Perinatal data on 70,386 singleton births in 1998-2001 were used in multivariable analyses on three groups: all women combined, all hypertensive women and women with pregnancy hypertension only, in order to identify independent risk factors for requirement for level II/III care, preterm birth, small for gestational age (SGA) birth and maternal length of stay greater than 7 days. RESULTS: The risks for the four morbidities were all increased among women with hypertension compared with normotensive women. Those with pre-existing hypertension had the lowest risk (with odds ratios (OR) 1.26-2.90). Pregnancy hypertension held the intermediate position (OR 1.52-5.70), while superimposed pre-eclampsia was associated with the highest risk (OR 2.00-8.75). Among women with hypertension, Aboriginality, older maternal age, nulliparity and pre-existing or gestational diabetes increased the risk for level II/III nursery care, preterm birth and prolonged hospital stay. Smokers had shorter stays, which may be related to their decreased risk of having a Caesarean section or operative vaginal delivery. Asian women, Aboriginal women, smokers and unemployed women had an increased risk for having an SGA baby, while women with pre-existing or gestational diabetes had a reduced risk. CONCLUSIONS: Among hypertensive pregnant women, nulliparity, older maternal age, Aboriginality, unemployment and diabetes are independent risk factors for one or more major adverse pregnancy outcomes. Smoking does not always worsen the outcome for hypertensive women except for SGA births.

Vdelta2-Jalpha rearrangements are frequent in precursor-B-acute lymphoblastic leukemia but rare in normal lymphoid cells.

The frequently occurring T-cell receptor delta (TCRD) deletions in precursor-B-acute lymphoblastic leukemia (precursor-B-ALL) are assumed to be mainly caused by Vdelta2-Jalpha rearrangements. We designed a multiplex polymerase chain reaction tified clonal Vdelta2-Jalpha rearrangements in 141 of 339 (41%) childhood and 8 of 22 (36%) adult precursor-B-ALL. A significant proportion (44%) of Vdelta2-Jalpha rearrangements in childhood precursor-B-ALL were oligoclonal. Sequence analysis showed preferential usage of the Jalpha29 gene segment in 54% of rearrangements. The remaining Vdelta2-Jalpha rearrangements used 26 other Jalpha segments, which included 2 additional clusters, one involving the most upstream Jalpha segments (ie, Jalpha48 to Jalpha61; 23%) and the second cluster located around the Jalpha9 gene segment (7%). Real-time quantitative PCR studies of normal lymphoid cells showed that Vdelta2 rearrangements to upstream Jalpha segments occurred at low levels in the thymus (10(-2) to 10(-3)) and were rare (generally below 10(-3)) in B-cell precursors and mature T cells. Vdelta2-Jalpha29 rearrangements were virtually absent in normal lymphoid cells. The monoclonal Vdelta2-Jalpha rearrangements in precursor-B-ALL may serve as patient-specific targets for detection of minimal residual disease, because they show high sensitivity (10(-4) or less in most cases) and good stability (88% of rearrangements preserved at relapse).

Risk factors for hypertension during pregnancy in South Australia.

OBJECTIVE: To identify risk factors for hypertension in pregnancy among South Australian women. DESIGN: A population-based retrospective analysis using the South Australian perinatal data collection for 1998-2001. METHODS: Three groups of women with hypertension (pre-existing hypertension, pregnancy hypertension, and superimposed pre-eclampsia) were compared with normotensive women using unconditional logistic regression analysis on 70,386 singleton births to identify sociodemographic and clinical risk factors for hypertension in pregnancy. RESULTS: Nulliparity, Aboriginal race and Caucasian race (compared with Asian) and pre-existing and gestational diabetes were demonstrated to be risk factors for all hypertensive disorders, as was increasing maternal age for pre-existing hypertension and superimposed pre-eclampsia. Risk was increased for pregnancy hypertension and superimposed pre-eclampsia among women who gave their occupation as 'home duties' and also for superimposed pre-eclampsia among unemployed women. Women with hypertension were more likely to give birth in teaching hospitals. Urinary tract infections were not found to be a risk factor for any type of hypertension. Smoking during pregnancy was protective for all types of hypertension. CONCLUSIONS: The present study used a statewide population perinatal database and has confirmed that Aboriginal race, Caucasians, nulliparity, and pre-existing and gestational diabetes are independent risk factors for all types of hypertension in pregnancy. Increasing maternal age increased the risk for pre-existing hypertension and superimposed pre-eclampsia. There appeared to be appropriate referral of women with hypertensive disorders to teaching hospitals. A new finding is the increased risk among unemployed women and women engaged in home duties.